Tag Archives: first metatarsophalangeal joint

Unilateral Versus Bilateral Same-Day Surgery Outcomes for Hallux Valgus: An Eight Year Prospective Cohort Study

by Jill Dawson, DPhil1emailsm, Michele Peters, PhD2emailsm, Crispin Jenkinson, DPhil3emailsm, Helen Doll, DPhil4emailsm, Grahame Lavis, BSc (Hons)5emailsm, Robert Sharp, MA FRCS (Ortho)6emailsm, Mark Rogers, FRCS (Ortho)7emailsm, Paul Cooke, ChM FRCS8emailsm

The Foot and Ankle Online Journal 5 (11): 2

Objective: To evaluate patient-reported outcomes and satisfaction 8 years following hallux valgus (HV) surgery and compare unilateral and bilateral cases.
Methods: Prospective Cohort with postal follow-up patient survey. Consecutively-recruited patients self-completed the Manchester-Oxford Foot Questionnaire (MOxFQ) ≤ 4 weeks before surgery. Of 91 patients proceeding to one-stage HV surgery (on 124 feet, 23 (18.5%) receiving further surgery), 69 (78%) of 88 eligible patients (representing 95/124, 77% feet: 43/95, 45.3% unilateral, 52/95, 54.7% bilateral) returned a follow-up questionnaire including the MOxFQ and standard satisfaction rating for surgical outcome around 8 years (range 7.4 to 8.9) later.
Results: Of 69 respondents, mean pre-operative age 49.8 (SD 12.5) years, 66 (95.7%) were female. Reporting on 95 feet, 78 (82.1%) patients were either ‘Very pleased’ (All 53/95, 55.8%; unilateral: 22/43, 51.2; bilateral 31/52, 59.6%) or ‘Fairly pleased’ (All 25/95, 26.3%; unilateral 13/43, 30.2; bilateral 12/52 23.1) with the outcome; with 17/95 (17.9%) ‘Not very pleased/very disappointed’. Change in all 3 MOxFQ scales showed a significant linear relationship with satisfaction ratings (ANOVA p<0.001). The MOxFQ pain scale showed greatest change (decrease in score) associated with being ‘Very pleased’ (mean (95% CI) reduction in score: Pain -48.0 (-42.8 to -53.2); Walking/Standing -38.4 (-32.0 to -44.8); Social-Interaction -43.1 (-36.9 to -49.4)
Conclusions: At 8 years following HV surgery, the majority of patients were pleased with the outcome. Simultaneous bilateral HV correction produced results that were no worse than unilateral correction. Change in the MOXFQ pain scale is particularly important in interpreting patients’ satisfaction with surgery.

Key Words: Foot pain, hallux valgus, bunionectomy, first metatarsophalangeal joint

Accepted: October, 2012

Published: November, 2012

ISSN 1941-6806
doi: 10.3827/faoj.2012.0511.0002


Hallux valgus (HV) is a common condition, particularly in women.[1,2] HV can present unilaterally or bilaterally and is characterized by lateral deviation of the big toe and medial deviation of the first metatarsal with progressive subluxation of the first MTP joint.[1] The condition can be painful and disabling and has been shown to have a detrimental effect on quality of life.[3]

It is one of the most common indications for foot surgery, where between a quarter and a third of patients are dissatisfied with the outcome[4]; although many factors can affect outcomes and satisfaction.[5]

The evaluation of outcomes following HV correction tend to represent a relatively short period (i.e. 12 months or less) following surgery with few studies involving validated patient-reported outcome measures.[4] Standardized patient-reported methods of assessing outcomes, (particularly those devised with patients’ input), reflect the patients’ rather than the clinicians’ perspective[6,4,7] and are independent of the surgical team.

Where HV is bilateral, the question of whether patients do better to have both feet treated at the same time, or not, has received some attention, although again, outcomes evaluation has tended to be relatively short-term and not patient focused.[8]

This paper presents patient-reported outcomes data based on a service evaluation survey conducted of consecutive patients who had received surgery for HV at one center, between 7 and 9 years previously, and who had provided baseline data prior to their surgery. Results are also broken down to compare patients who had unilateral versus bilateral HV surgery.

Methods

Local ethics committee approval was obtained (Applied and Qualitative Research Ethics Committee reference A02.009) for the original study;[9] postal service evaluation survey approved by the institution’s Integrated Governance Committee (August 2011).

At baseline 100 out of 111 consecutive patients were approached and consented to take part, 38 of whom were booked for bilateral HV correction. Of these, 91 (/100) patients proceeded to surgery, of whom, 33 (/91, 36%) had bilateral surgery (total=124 operations/feet). All surgery was completed on the one day (i.e. no 2-stage operations).

Prior to conducting the postal survey, patients’ current address details were checked through the hospital information system. Questionnaires were mailed together with cover letters and a stamped addressed envelope. Where any questionnaires were returned as ‘unknown’ the patient’s last known GP practice was contacted by a member of the foot and ankle surgical team. In all other cases of non-response after 4 weeks, a reminder letter was sent out with a second copy of the survey questionnaire.

Overall, 2 patients were known to have died and one had emigrated. Of the remaining 88 eligible patients, 69 (/88, 78%) returned a completed follow-up survey questionnaire, with no response obtained from a further 19 (/88, 22%) patients. Of the 69 respondents, 26 (38%) were bilateral cases who contributed outcome data regarding two foot (HV) operations. Thus 69 patients completed questionnaires regarding ~8 year outcomes for 95 operations/feet. Their mean pre-operative age was 49.8 (SD 12.5) years; 66 (66/69, 95.7%) were female. The mean period of follow-up (original operation date until date of survey completion) was 8.03 (SD 0.37, range 7.41 to 8.87) years.

Assessments

Patients completed the Manchester-Oxford Foot Questionnaire (MOxFQ) for each foot having surgery as well as the SF-36 general health survey (completed once per patient), at a pre-admission clinic, within 4 weeks prior to surgery. These measures were completed again as part of the 2011 postal survey.

The MOxFQ has previously been validated with patients undergoing HV surgery.[9,10] It was subsequently revalidated in a separate study involving all patients undergoing foot or ankle surgery in a 12 month period, at one regional center.[11,12] It contains 16 items, each with 5 response options, comprising 3 separate underlying dimensions: foot pain (5 items), walking/standing problems (7 items) and issues related to social interaction (4 items), including feelings of self-consciousness about foot/footwear appearance (‘cosmesis’).

Item responses are each scored from 0 to 4, with 4 representing the most severe state. The scale score representing each dimension is produced by summing the responses to each item within that dimension. Raw scale scores are then converted to a 0 to 100 point scale (100=most severe).

The SF-3613 contains 36 items and is a widely used generic health status instrument. It provides scores on 8 dimensions of health: physical functioning, social functioning, role limitations due to physical problems, role limitations due to emotional problems, mental health, energy/vitality, bodily pain and general health perceptions over the last 4 weeks. Scores for each dimension are produced by summing the responses to each item within that dimension and then converting the raw scores to a 0 to 100 point scale, (100= good health) general population norm set at 50, SD 10.

The postal survey also included a transition item, (‘How are the problems related to your foot now, compared to before your surgery?’, response options: no problems now, much better, slightly better, no change, slightly worse, much worse), and 3 questions regarding patients’ satisfaction with the outcome (‘Overall, how pleased have you been with the result of the surgery on your foot?’; ‘How pleased are you with the appearance of your foot?’; ‘How pleased are you with the range of shoes that you can wear?’); each with response options: ‘Very pleased’, ‘Fairly pleased’, ‘Not very pleased, ‘Very disappointed’.

The transition and satisfaction items were asked in relation to each foot that had received surgery approximately 8 years previously. Additional questions asked whether the patient had received further surgery on the same foot since the original operation, and whether or not the patient currently had a problem with their other (contralateral) foot. A surgeon also checked for details of any subsequent foot surgery via the hospital patient information system.

Statistical analysis

Power calculations had determined that a sample size of 100 would give 80% power to detect, at p<0.05, a difference in proportions of 25%-30% and a medium effect size of around 0.55 between two groups of equal size. Data analysis was undertaken within SPSS release 17.0.14 Data are presented as mean (SD) at each assessment and mean change (SD) from pre-surgery to 8 years post surgery (post-surgical score minus pre-surgical score), with paired t-tests used to assess the statistical significance of any observed change. Statistical significance was taken at the 5% level throughout.

Some analyses (e.g. patient characteristics and SF-36 outcomes) have been conducted at the level of the patient (n=91 who had surgery, n=69 questionnaire respondents), while analyses of foot-specific outcomes and satisfaction with surgery have been conducted at the level of the foot (n=124 foot operations, involving n=95 completed questionnaires). Since 26 patients had bilateral operations, (which threatened the independence of patients’ observations on their two individual feet), baseline analyses were repeated three times: on the data for left feet only (n=61/124, 49.2%), right feet only (n=63/124, 50.8%), and for both feet (n=124; with 52 patients contributing data for both left and right feet). The results were, in fact, very similar for all analyses, and thus only the analyses that combined data for left and right feet are presented here.

The effect size (ES) statistic has been used to demonstrate the magnitude of change detected by the different outcome measures. This is calculated by dividing the mean change in scores (post-surgical score minus pre-surgical score) by the pre-surgical SD, this standardization by the SD allowing direct comparison to be made between instruments with different scales.[15]

An ES of 1.0 (or -1.0 for scales in which improvement is associated with a decrease in score) is equivalent to a change of one SD in the sample. Values of 0.2, 0.5 and 0.8 are typically regarded as indicating small, medium and large degrees of change, respectively.[15,16]

The relationship between MOxFQ change scores and four levels of response on the satisfaction with surgery rating have been explored using analysis of variance (ANOVA) test for linearity and Tukey post-hoc tests.

Results
Survey respondents versus non-respondents

Survey non-respondents were somewhat more likely to be male, younger, and employed, than respondents (no differences were statistically significant), but were no more likely to have received bilateral surgery on the original operation date. Respondents and non-respondents did not differ significantly with regard to the type of surgery that they received (Foot level analysis/ Respondents: Scarf procedure, with or without Akin 57/68, 83.8%; chevron 8/68, 11.8%; ’another form of surgery’ 3/68, 4.4% versus Non-respondents: Scarf procedure, with or without Akin 17/21, 81.0%; chevron 4/21, 19.0%; ’another form of surgery’ 0/21, 0%); or with regard to the need to have subsequent surgery (including revision) to the same foot (Foot level analysis/ Respondents 17/95, 17.9% versus non-respondents 6/29, 20.7%). Respondents’ pre-operative MOxFQ scores were all somewhat higher (worse) than those of non-respondents, particularly for the Walking/standing scale, although they did not differ significantly [MOxFQ Walking/standing (W/S), Pain and Social-Interaction (SI) scores: Respondents’ mean (SD) scores: W/S 47.3 (25.5); Pain 55.3 (17.8); SI 47.7 (22.5) versus Non-respondents’ mean (SD) scores: W/S 38.5 (21.2); Pain 49.8 (22.6); SI 43.8 (22.2).]

Unilateral versus Bilateral patient characteristics

There were no significant differences in the characteristics of patients who received unilateral versus bilateral surgery in relation to age, sex, qualifications or work status. Unsurprisingly, while 15 of the 43 patients having unilateral surgery reported having a problem affecting the contralateral foot (at baseline), all patients having bilateral surgery reported this (15/43, 34.9% versus 26/26, 100.0%; p<0.001).

Outcomes
Person-level analyses

Table 1 shows pre-, post-operative and change scores, plus effect sizes (ESs), for the generic SF-36, for all patients, and separately for patients having unilateral and bilateral surgery.

Overall, with the exception of the Pain domain (ES 0.7), most of the SF-36 domains showed small to moderate (in terms of ES) increases in score (i.e., improvement) compared with patients’ pre-operative baseline measures ~8 years previously. The largest improvements in health status (i.e. ES ≥ 0.4) were all highly significant (P ≥ 0.001).

SF-36 pre-operative scores were mostly slightly higher (better) in patients having unilateral, compared with those having bilateral surgery, although none of these differences were statistically significant (p value range 0.21 to 0.79). SF-36 scores were even more similar for unilateral and bilateral surgical groups when analyses were repeated after excluding patients who only had a unilateral foot problem at baseline (results not shown). Conversely, SF-36 post-operative scores were mostly lower (worse) in patients having unilateral, rather than bilateral surgery, although again, none of these differences were statistically significant (p value range 0.10 to 0.70).

8yrHAVTable1

Table 1 Mean pre-operative, 8 year post-operative and change values, plus effect sizes for SF-36 patient-reported sub-scales in all patients, and comparing those who received unilateral versus bilateral surgery to correct hallux valgus [Patient-level analysis].

8yrHAVTable2

Table 2 Mean pre-operative, 8 year post-operative and change values, plus effect sizes for MOxFQ patient-reported domains/sub-scales, representing all feet that received bunion surgery and comparing outcomes of operations that represented a unilateral versus bilateral procedures [Foot-level analysis].

8yrHAVTable3

Table 3 Aspects of patient-rated satisfaction 8 years following surgery to correct hallux valgus deformity [Foot-level analysis N=95].

The magnitude of the differences between the pre- and post-operative SF-36 scores, within the unilateral and bilateral groups, are shown most clearly by the ESs. (Table 1) Amongst those who had unilateral surgery, ESs for the SF-36 domains were all small (≤ 0.3) with the exception of the Pain domain, which was moderate (ES 0.6); while amongst those who had bilateral surgery, most of the SF-36 domains achieved moderate ESs (ES 0.5 to <0.8); although the ES for the Pain domain was large (ES 0.8).

A comparison of the SF-36 change score differences between the unilateral and bilateral surgical groups revealed differences to be statistically significant in 3 domains: Role Physical (Uni/Bi mean change, SD: 1.4, 30.5/ 20.7.30.7; p=0.02), Social Functioning (Uni/Bi mean change, SD: 3.6, 28.6/15.6, 21.6; p=0.03) and Mental Health (Uni/Bi mean change, SD: 3.6, 15.3/ 10.0, 12.4 p=0.004), with bilateral cases registering greater change on these scales than unilateral cases.

Foot level analyses

Within the period (~8 years) following the original operation, further surgery had been conducted on the same foot in 23 cases (23/124, 18.5%). Overall, each MOxFQ scale/domain registered a very large ES (WS -1.1, Pain -1.8, SI -1.3), representing decreases (i.e., improvement) from the pre-surgery baseline scores 8 years previously, with all related change scores highly significant (p<0.001). (Table 2) The magnitude of the differences/ changes between the pre- and 8 year post-operative MOxFQ scores within the unilateral and bilateral subgroups, are shown by the ESs. Amongst those who had unilateral surgery, ESs for all 3 MOxFQ scale domains were large (≥ -0.8); while ESs amongst those who had bilateral surgery, were slightly larger (ES ≥ -1.1). These changes over time were all highly significant.

A comparison of the change score differences between the unilateral and bilateral groups revealed very similar (and statistically insignificant) mean change scores for the differences in W/S and Pain scales, but the change scores did differ significantly for the SI domain, (which assesses aspects of work and social participation, footwear and ‘cosmesis’), with bilateral cases registering greater change on this scale than unilateral cases (Uni/Bilateral mean change, SD: -19.8, 29.4 versus -36.9, 25.5; p<0.01). The difference between these change scores (of 17.1 score points) was greater than the Standard Error of Measurement (SEM) (11.92 score points) that has previously been estimated for this scale.[10]

Patient satisfaction [per foot]

Table 3 reports patients’ responses to the transition and satisfaction items asked in relation to each foot that received surgery. Comparisons are made between responses that relate to a unilateral operation versus those relating to each foot comprising a bilateral (same day) procedure. Overall, more than half of the foot operations (53, 55.8%) were associated with patients being ‘Very pleased’ with the outcome of their surgery and a high proportion (78, 82.1%) were rated as either ‘Very pleased’ or ‘Fairly pleased’.

Three-quarters (72, 75.8%) of pre-operative foot problems were now reported as non-existent (‘No problems now’) or ‘Much better’. Poorer satisfaction ratings were given specifically in relation to the range of shoes patients could now wear (35, 36.8% ‘Very pleased’) and with the appearance of the foot (45, 47.4% ‘Very pleased’). Bilateral operations attracted the highest proportion of extremely positive satisfaction ratings across all 4 items, compared with unilateral operations, although none of these differences were statistically significant.

Relationship between patient satisfaction and foot outcome measures (MOxFQ)
[foot-level analysis]

Figures 1A and 1B show the mean 8 year post-operative MOxFQ W/S, Pain and SI scale scores and change scores respectively, together with 95% confidence intervals (CIs), broken down according to patients’ responses [‘Very pleased’, ‘Fairly pleased’, ‘Not very pleased’, Very disappointed’] to the satisfaction item: ‘How pleased are you now with the result of your foot surgery?’

Regarding post-operative MOxFQ scale scores (figure 1a), mean scores for all 3 MOxFQ scales that were associated with the most positive (‘Very pleased’) satisfaction rating (Mean, 95% CIs: W/S 8.8, 4.4 to -13.1; Pain 8.9, 5.1 to -12.8; SI 4.6, 1.9 to -7.3) were distinctly lower/better than scores associated with other responses to the satisfaction item with all patients who were ‘Very pleased’ with the outcome scoring <14 on each MOxFQ scale. Thus, there was also no overlap between 95% CIs for mean scores related to this response and those related to any other response. However, most of the 95% CIs associated with all other (less positive) ratings on the transition item overlapped.

Further analyses (ANOVA with testing for linear trend and Tukey post-hoc comparisons) confirmed significant linear trends in MOxFQ domain score across categories of response (p<0.001).

8yrHAVFig1a 8yrHAVFig1b

Figure 1A and 1B MOxFQ 8 year post-operative scores related to different levels of response concerning patient satisfaction.

In particular, however, post-operative MOxFQ scores associated with the ‘Very pleased’ response were significantly different (p<0.001) from scores associated with other ‘less pleased’ responses, while scores associated with these less pleased responses were generally not significantly different from each other.
Regarding MOxFQ scale change scores (figure 1b), mean change in the MOxFQ scales associated with the most positive rating (‘Very pleased’) to the satisfaction item was greatest in the Pain domain (Mean, 95% CIs: Pain -48.0, -42.8 to -53.2; W/S -38.4, -32.0 to -44.8; SI -43.1; -36.9 to-49.4). This change in the Pain domain was considerably greater than pain change scores associated with all other responses to the satisfaction item, with the 95% CIs not overlapping with those of any other category of response. This was not the case in relation to MOxFQ W/S and SI scales, where overlap of mean change score 95% CIs occurred across most levels of response to the satisfaction item. The response options ‘not very pleased’ or ‘Very disappointed’ represented small numbers of operations/feet and therefore associated mean MOxFQ change scores generally had wide 95% CIs which tended to overlap with 95% CIs for most of the MOxFQ change scores associated with other patient responses.

Further analyses (ANOVA, with Tukey post-hoc comparisons) confirmed that the change in the MOxFQ pain scale that was associated with the ‘Very pleased’ response was significantly different from pain changes associated with other ‘less pleased’ responses; while change scores associated with the less pleased responses were generally not significantly different from each other. Associations between changes in the MOxFQ W/S and SI scales and responses to the satisfaction item were found to be not so clear-cut, with change scores associated with the ‘very pleased’ response not significantly different from other responses, although change on the MOxFQ SI scale that was associated with the ‘very disappointed’ response was significantly different from changes associated with any other responses (p<0.001)

Discussion

This paper has presented standard patient-reported outcomes at around eight years following one-stage surgery for HV, based on a response rate of 78% to a postal survey and compared with patients’ pre-operative data. This is the first time that a validated foot-specific measure (the MOxFQ) has been used to evaluate and benchmark long-term outcomes following surgery for HV.

Just over a third of patients who received unilateral foot surgery reported having a problem (unspecified) with the contralateral foot at baseline, but otherwise the characteristics of these patients, which included their pre-operative general health status (SF-36) scores, did not differ significantly from those of patients having bilateral surgery. This suggested that ill health was not a likely explanation for patients with bilateral foot problems having unilateral, rather than bilateral, surgery.

An examination of pre-operative versus 8 year post-operative changes in patients’ health status showed that the 3 foot-specific domains of the MOxFQ detected changes that were much greater and more consistent than was the case for those detected by the generic SF-36 domains. This was unsurprising, as generic measures detect perturbations in health-related quality of life that can be due to any condition affecting any part of the body. Over time, the likelihood increases that symptoms related to a different condition (‘noise’) will arise that ‘drown out’ changes that are specific to the condition of interest. Nonetheless, in the current study, when comparisons were made between bilateral and unilateral cases, significant differences in changes between the two groups were detected by the SF-36, albeit by the Social Functioning, Role Physical and (in particular) Mental Health domains, and not by the more obviously relevant domains (i.e. Physical function or Pain).

Interestingly, when changes in MOxFQ scores were compared for bilateral and unilateral operations, it was the Social-Interaction scale, rather than the Pain or Walking-Standing scales that detected a large and significant difference between the two groups. The Social-Interaction scale addresses work/everyday and social/recreational activities, patients’ attitude to their foot appearance (‘cosmesis’) and wearable range of shoes, which overall construct chimes with aspects of the more Social-Psychological oriented SF-36 scales. The magnitude of the difference (in the S-I scale) observed between the two groups was greater than the SEM previously estimated for this scale. Changes greater than the SEM of a PROM are considered to be a real (ie. beyond the measurement error of the scale) and likely clinically relevant magnitude of change/difference when comparing outcomes between patient groups.[17]

A high proportion of the foot operations (over 80%) were associated with respondents being at least ‘Fairly pleased’ with the outcome of surgery. Bilateral operations attracted the highest proportion of extremely positive satisfaction ratings. Limitations in the range of shoes respondents could now wear (which could, of course, be influenced by either or both feet) and with their attitude to the appearance of their foot, since surgery, appeared important influences on patients’ satisfaction with the outcome of their surgery.

Few studies have investigated the medium to long-term outcomes of surgery for HV and those that have mostly used a retrospective design. Findings are also commonly restricted to reporting radiographic changes and a clinical assessment (e.g. the AOFAS hallux metatarsophalangeal (MTP)-interphalangeal (IP) rating,[18,19] although some have included a patient satisfaction rating (e.g. a visual analogue scale; or a question with ordinal response options).[20] One larger study, included 200 patient interviews to gain insights into patient satisfaction with the surgical outcome and with their pre-operative expectations.[6]

Findings here highlighted the importance of footwear problems, the alleviation of pain and restoration of adequate walking function as being the most important influences in the outcome of surgery for HV.[6]

Other studies have compared the results of unilateral versus simultaneous bilateral correction for HV. One, based on AOFAS scores, patient satisfaction rating and radiographic outcomes (follow-up period ‘at least 12 months’) concluded that simultaneous bilateral HV correction produced results that were no worse than unilateral correction.[21] Our own analysis of longer-term patient-reported data certainly supports this position.

References

1. Coughlin MJ. Hallux valgus. JBJS 1996 78A: 932-966 .  [PubMed]
2. Dawson J, Thorogood M, Marks SA, Juszczak E, Dodd C, Lavis G, Fitzpatrick R. The prevalence of foot problems in older women: a cause for concern. J Public Health Med 2002 24: 77-84. [PubMed]
3. Gilheany MF, Landorf KB, Robinson P. Hallux valgus and hallux rigidus: a comparison of impact on health-related quality of life in patients presenting to foot surgeons in Australia .  Foot Ankle Res 2008 1: doi:10.11186/1757-1146-1-14.[PubMed]
4. Ferrari J, Higgins JPT, Prior TD. Interventions for treating hallux valgus (abductovalgus) and bunions. DOI: 10.1002/14651858.CD000964.pub3. Cochrane Database Syst Rev 2009;(2):CD000964.5.
5. Dawson J, Coffey J, Doll H, Lavis G, Sharp RJ, Cooke P, Jenkinson C.  Factors associated with satisfaction with bunion surgery in women: a prospective study. The Foot 2007; 17:119-125. [Website]
6. Schneider W, Knahr K. Surgery for hallux valgus. The expectations of patients and surgeons. Int Orthop 2001; 25:382-385. [PubMed]
7. Parker J, Nester CJ, Long AF, Barrie J.  The problem with measuring patient perceptions of outcome with existing outcome measures in foot and ankle surgery. Foot Ankle Int 2003 24: 56-60. [PubMed]
8. Murray O, Holt G, McGrory R, Kay M, Crombie A, Kumar CS. Efficacy of outpatient bilateral simultaneous hallux valgus surgery. Orthopedics 2010; 33(6):394. [PubMed]
9. Dawson J, Coffey J, Doll H, Lavis G, Cooke P, Herron M, Jenkinson C.  A patient-based questionnaire to assess outcomes of foot surgery: validation in the context of surgery for hallux valgus.  Qual Life Res 2006 15:1211-1222. [PubMed]
10. Dawson J, Doll H, Coffey J, Jenkinson C; Oxford and Birmingham Foot and Ankle Clinical Research Group. Responsiveness and minimally important change for the Manchester-Oxford foot questionnaire (MOxFQ) compared with AOFAS and SF-36 assessments following surgery for hallux valgus. Osteoarthritis Cartilage 2007 15: 918-931.[PubMed]
11. Dawson J, Boller I, Doll H, Lavis G, Sharp R, Cooke P, Jenkinson C. The MOxFQ patient-reported questionnaire: assessment of data quality, reliability and validity in relation to foot and ankle surgery. doi:10.1016/j.foot.2011.02.002. Foot 2011 21:92-102. [PubMed]
12. Dawson J, Boller I, Doll H, Lavis G, Sharp R, Cooke P, Jenkinson C. Responsiveness of the Manchester-Oxford Foot Questionnaire (MOxFQ) compared with AOFAS, SF-36 and EQ5D assessments following foot or ankle surgery. JBJS 2012 94B: 215-221. [PubMed]
13. Ware-JE J, Sherbourne CD. The MOS 36-item short-form health survey (SF-36). I. Conceptual framework and item selection. Med Care 1992; 30(6):473-483. [PubMed]
14. SPSS Inc. SPSS (IBM) statistical software. Release 17.0. Headquarters, 233 S. Wacker Drive, 11th floor Chicago, Illinois 60606, USA.: SPSS Inc.; 2008.
15. Kazis LE, Anderson JJ, Meenan RF. Effect sizes for interpreting changes in health status. Med Care 1989; 27(3 Suppl):S178-S189.[PubMed]
16. Cohen J. Statistical power analysis for the behaviora] sciences. New York: Academic Press; 1997.
17. Wyrwich KW, Tierney WM, Wolinsky FD. Using the standard error of measurement to identify important changes on the Asthma Quality of Life Questionnaire. Qual Life Res 2002; 11:1-7. [PubMed]
18. Kitaoka H, Alexander I, Adelaar R, Nunley JA, Myerson MS, Sanders M. Clinical rating systems for ankle-hindfoot, midfoot, hallux and lesser toes. Foot Ankle Int 1994 15:349-353. [PubMed]
19. Fuhrmann RA, Zollinger-Kies H, Kundert HP. Mid-term results of scarf osteotomy in hallux valgus. Int Orthop 2010 34: 981-989. [PubMed]
20. Bhavikatti M, Sewell MD, Al-Hadithy N, Awan S, Bawarish MA.. Joint preserving surgery for rheumatoid forefoot deformities improves pain and corrects deformity at midterm follow-up. Epub ahead of print. Foot 2012. [PubMed]
21. Lee KB, Hur CL, Chung JY, Jung ST. Outcomes of unilateral versus simultaneous correction for hallux valgus. Foot Ankle Int 2009 30:120-123. [PubMed]


Address Correspondence to: Jill Dawson DPhil, Senior Research Scientist & University Research Lecturer, Department of Public Health, University of Oxford, Old Road Campus, Oxford OX37LF & Visiting Professor, Oxford Brookes University, Oxford. Email: jill.dawson@dph.ox.ac.uk

1,2Senior Research Scientist & University Research Lecturer1, Department of Public Health, University of Oxford, Old Road Campus, Oxford OX37LF & Visiting Professor1, Oxford Brookes University, Oxford
3Professor of Health Services Research, Department of Public Health, University of Oxford, Old Road Campus, Headington, Oxford OX37LF.
4Senior Medical Statistician, Department of Public Health, University of Oxford, Old Road, Oxford OX37LF.
5,6,7,8Consultant of Podiatric5 and Orthopaedic6,7,8 Surgery, Nuffield Orthopaedic Centre, Windmill Road, Oxford OX37LD.

Prolidase Deficiency: A child with persistent lower extremity ulcerations

by Morris Tyrone Haywood, DPM

The Foot and Ankle Online Journal 4 (4): 4

This case report describes a pediatric patient with prolidase deficiency, a rare, autosomal recessive metabolic disorder with severe dermatological manifestations, particularly ulcers of the lower extremities. While this condition has seldom been reported, it may be more common than previously acknowledged. An eight year-old Amish girl with prolidase deficiency presents with ulcerations on the feet and lower legs. Clinical presentation and the pathogenesis of prolidase deficiency are discussed. During the past five years various treatment options have been attempted. These have included ointments containing growth hormones, amino acids, antibiotics and numerous over the counter products. Skin grafts were also attempted for this patient. To date, no treatment has proved significantly successful. Currently there is no cure for this condition.

Key words: Energy consumption, First metatarsophalangeal joint, First metatarsal, Insolia Flex, Comfort.

Accepted: February, 2011
Published: April, 2011

ISSN 1941-6806
doi: 10.3827/faoj.2011.0404.0004


Prolidase deficiency (PD) is a rare, inherited, autosomal recessive, inborn error of amino acid metabolism that affects collagen maturation. Eighty-five percent of the patients present with dermatological symptoms, including lower extremity ulcers, with pedal ulcers as the common clinical finding at diagnosis in 50% of the patients. [1] These chronic leg ulcers are usually irregularly shaped with prominent granulation tissue. They are often resistant to various topical, systemic, and surgical treatments making them slow to heal. [2]

In 1968, Goodman, et al., were the first to describe prolidase deficiency. [3] Powell, et al., in 1974 further defined the clinical characteristics by documenting the absence of prolidase enzyme in association with the characteristic clinical features of prolidase deficiency. [4] Prolidase enzyme cleaves iminodipeptides with C-terminal proline or hydroxyproline. The gene encoding this enzyme is located at chromosome 19. Prolidase deficiency has an incidence of 1-2 per 1,000,000 persons with an estimated 60 cases described in the literature. [5]

The clinical features observed with prolidase deficiency vary from asymptomatic to a range of symptoms, including chronic leg ulcers, recurrent infections, characteristic facies, mental retardation, and splenomegaly. [4] These symptoms normally occur in the first year of life but can remain dormant in an affected individual until the second decade of life. [6,7]

In acute ulcerations, vascular changes including occlusion of medium-sized vessels with amyloid deposits and perivascular infiltration of neutrophils have been observed. [9] Additionally, Pierand, et al., cited vascular wall thickening and infiltration of mononuclear cells and neutrophils in pre-ulcerative indurated lesions. [10] Yasuda, et al., believed the difference in the severity of skin lesions and the mental retardation between two patients may have been related to the relative superoxide-generating activity of polymorphonuclear cells (PMN). [11] These vascular and tissue changes result in chronic lower extremity ulcerations and other dermatological conditions, including scarring, scaly abnormally thick skin, photosensitivity telangiectasia, poliosis, and lymphedema. [12] Researchers have yet to determine why these chronic ulcers occur mainly in the lower extremities. [13]

Case Report

An 8 year-old Amish girl (patient x) presented with a six year history of lower extremity ulcerations, primarily on her feet. Recently, the number of ulcerations has increased, causing her more pain and discomfort. The patient’s past medical history is significant for chronic lower extremity ulcers associated with prolidase deficiency.

A physical examination of the lower extremity revealed multiple lesions in various stages of healing on her feet and legs. (Figs.1, 2A AND 2B and 3) The ulcerations on the right foot also had diffuse dyspigmentation, erythema and scaly skin. (Fig. 3) However, digital clubbing was more visible on her hands compared to her feet. She was in significant pain with ambulation and compensated by toe walking. Her parents confirmed that their child is still primarily a toe walker to avoid plantar foot pressure. Both of the patient’s feet rest in a pronounced equinus type position non- weightbearing. The patient uses bactroban and topical zinc daily on the ulcers and takes Tylenol #3 for the foot pain. Although flexible, the patient has dorsiflexion at the ankle that can reach only 90° with effort and some discomfort.

Figure 1   Irregularly shaped, intact skin with subcutaneous micro-vascular bleeding lesions.

 

Figures 2A and 2B  Dorsal left foot with erythema, edema at digits and scar tissue from healed ulcerations. (A)  Plantar right foot with scaly erythematous skin. (B)

Figure 3   Close-up of plantar right foot with scaly erythematous skin.

The patient has tight Achilles tendons bilaterally. Additionally, the patient exhibits pronounced ligamentous laxity in many upper and lower body joints. For shoe gear, she wears a child’s size 13 extra depth sneaker with velcro straps. The shoe also has an inner sole, comprised of a 1/16-inch pink plastazote cover on top of a 1/16-inch layer of white poron. At the heel plantarly, a small portion of Neo-Sponge covers the white poron.

In the first sixth months of her life, the patient was healthy and normal. However, at seven months, she developed petechia associated with anemia and thrombocytopenia. Then at age two, the patient was diagnosed with prolidase deficiency (PD) and underwent an allogenic umbilical cord blood transplant from her HLA identical sister to treat the disease. This initial treatment modality failed to resolve the patient’s condition.

The patient’s first lower extremity lesion was prior to the transplant. A superficial puncture wound resulted in a small, but difficult-to-heal lesion. Multiple lesions appeared on her feet and legs approximately 3 months after her transplant. These lesions became a chronic condition with the foot ulcers being most resistant to treatment and somewhat compromised by socks and shoe gear.

These foot ulcers, which have been positive for fungus in the past, have resolved with using clotrimazole.

In regards to the patient’s development, the mother had a full term delivery with no complications. The patient met all her milestones without much delay, except she began walking at around 18 months. Although she is within the appropriate percentile on the chart, she is short in stature which her primary care physician attributes to the prolonged use of steroids. However, the patient is not deficient in growth hormone as cited in the literature of other prolidase deficiency patients. She is very limber; in her mother’s words the patient is very double-jointed.

Currently, the patient is seen approximately monthly in the Pediatric Hematology/ Oncology Clinic to receive intravenous immunoglobulin G therapy to treat hypogammaglobulinemia. The patient also suffers with other immune-deficiency-related illnesses, including recurrent pulmonary and eye infections for which she often takes prophylactic medications. Additionally, she has reactive airway disease requiring the periodic use of rescue and preventive inhalers as well as a cystic fibrosis vest and oxygen. She also has a history of adrenal and thyroid deficiency involving periodic replacement. Finally, she has some developmental delay but has a 90 to 100 percent psychosocial performance score. Although none of the patient’s siblings experienced similar medical problems, two paternal 1st male cousins died from complications of PD at 13 months and 7 years of age.

Diagnosing Prolidase Deficiency

Diagnosis is based on decreased prolidase activity in erythrocytes, leukocytes and skin fibroblasts as well as urinary excretion of C-terminal proline and hydroxyproline iminodipeptides with glycylproline dominating.10 Like most genetic disorders, PD can also be diagnosed in utero using amniocentesis or chorionic villus sampling.

Often laboratory abnormalities associated with prolidase deficiency include iron-deficiency anemia, thrombocytopenia, elevated liver enzymes, decreased growth hormone, and elevated serum immunoglobulins. [10,14] However, the patient in this study has hypoimmuglobulin, requiring monthly replacement.

The low incidence and prevalence of PD and its range of phenotypes makes the diagnosis of PD a challenge. Signs and symptoms normally occur in the first year of life, but can remain latent until the second decade.15 This possible delay results in early symptoms of PD being linked to many medical conditions and diagnoses. Often patients with PD may struggle for many years to obtain the correct diagnosis. In most cases, PD patients receive multiple medical treatments for the chronic symptoms with providers having no real understanding of the disease process or the incurable prognosis. To date, therapeutic intervention of PD focuses on healing the chronic lower extremity ulcers with minimal attention given to the underlying etiology of PD. This lack of an accurate diagnosis lends patients to often feel disenfranchised in hoping for a cure for their disease.

Difficulty in Treatment

A characteristic feature of the lower extremity ulcers in this disorder is resistance to most forms of treatment, including rejection of skin grafts. The difficulty in treating PD lower extremity ulcers is probably related to the abnormal collagen degradation and synthesis cycle, which cause urinary excretion of proline and glycine as well as the vascular changes in ulcerated tissue. The collagen comprising the dermal layer is frail in PD, causing skin to break down from normal physiological stress. Furthermore, the wound healing process is altered, because of the tissue lacking normal tension, thus causing the patient to be prone to dehiscence. Additionally, occluded vessels and abnormal infiltration of neutrophils contribute to an altered immune response comprised wound healing. These tissue and vascular changes predispose patients with PD to numerous recalcitrant wounds.

Discussion

During the past five years, the patient’s parents in this study have tried numerous products for treatment of their daughter’s lower extremity lesions. Some of these topical creams and ointments have been more beneficial than others. For instance, lidocaine ointment has been mixed with various other products to relieve pain. However, with each new product, some successes were gained for several months, then, as if her body had become accustomed to the medication, the lesions returned significantly worse or at least to the degree at the time treatment was initiated. For other ointments, a negative effect was sometimes immediately experienced by the patient or later developed.

Regranex, a growth hormone ointment FDA approved for diabetic ulcerations was used for one week before being discontinued because the patient experienced burning sensations. Several over the counter (OTC) ointments for treating burns and wounds were also tried, including B & W Ointment, an organic Amish product comprised of lanolin and honey; Wound-Be-Gone, a hydrophilic gel; and Merpelex, an emulsifying wax and paraffin. Unfortunately, all of these OTC products made the lesions dry and caused painful fissures. Another local product Wood’s Poultice made of bentonite clay and pine tar oils caused dry painful fissures on the feet but not the legs. Currently, the patient’s parents are applying an inexpensive triple antibiotic with zinc oxide on the feet and Wood’s Poultic to the legs. They have used this combination with daily dressing for over 12 months. Although this treatment regimen is not a cure, it keeps the lesions moist while slowly healing.

The literature has reported minimal results with other topical agents, vitamins, and antibiotics including dapsone, bactroban, ascorbic acid, and manganese. [14] The use of systemic and topical growth hormones, oral vitamins, and other supplements has provided minimal relief for a brief time. Lastly, surgical intervention using skin grafts has also been performed with limited success.

Some therapies target the pathophysiology of the disease by replacing the PD enzyme in the blood and providing collagen products to the wound. Enzyme replacement has been tried through blood transfusions, containing manganese activated prolidase enzyme, yet this costly treatment resulted in only a brief elevation in prolidase activity level. [16] There are some reports on the use of collagen dressings; however, most show no true benefits even though collagen products are thought to stimulate fibroblast activity and to improve the healing cascade. Finally, pulsed corticosteroid treatment has shown good results by inhibiting abnormal infiltration of neutrophils. [11]

While the patient’s current treatment is helpful, a different regiment will be attempted when this particular approach is no longer satisfactory. A combination ointment of proline and glycine has been described several times in the literature as beneficial. [17,18] The parent’s of this patient made several attempts of applying a compounded topical combination ointment of 5% proline and 5% glycine. After ointment application, an Adaptic wound dressing and dry gauze was then applied. Surprisingly, this treatment also was unsuccessful for this patient. She complained the ointment either burned when applied or made her itch. The ointment was temporarily discontinued for further evaluation. In the near future this combination may be manufactured with smaller percentages and/or other products. Tendon contractures resulting in foot deformity has been cited in this patient population, usually as a consequence of chronic ulcerations and scare tissue. [2] Additionally, the patient will possibly undergo an Achilles tendon lengthening procedure.

The main problem posed in the treatment of PD is that it is a rare disease, and therefore, attracts little interest from the pharmaceutical industry. [16] However, ulcerations in many disease processes are still a challenge to treat in a reasonable time frame. As the technology in wound care advances for treating our most common lesions, hopefully the treatment of chronic ulcers in PD will also improve.

References

1. Der Kaloustian VM, Freij BJ, Kurban AK. Prolidase deficiency: An inborn error of metabolism with major dermatological manifestations. Dermatology 164: 293-304, 1982.
2. Leoni A, Cetta G, Tenni R, Pasquali-Ronchetti I, Bertolini F, Guerra D, Dyne K, Castellani A. Prolidase deficiency in two siblings with chronic leg ulcerations: Clinical, biochemical, and morphologic aspects. Arch Dermatol 123: 493-499, 1987.
3. Goodman SI, Solomons CC, Muschenheim F, Mclntyre CA, Miles B, O’Brien D. A syndrome resembling lathyrism associated with iminodipeptiduria. Am J Med 45:152-159, 1968.
4. Powell GF, Rasco MA, Maniscalco RM. A prolidase deficiency in man with iminopeptiduria. Metabolism: Clinical Experimental 23: 505-513, 1974.
5. Kelly JJ, Freeman AF, Wang H, Cowen EW, Kong HH. An Amish boy with recurrent ulcerations of the lower extremities, telangiectases of the hands, and chronic lung disease. J Am Academy Dermatol 62: 1031-1034, 2010.
6. Lopes I, Marques L, Neves E, Silva A, Taveira M, Pena R, Vilarinho L, Martins E. Prolidase deficiency with hyperimmunoglobulin E: A case report. Pediatric Allergy Immunology 13: 140-142, 2002.
7. Shrinath M, Walter JH, Haeney M, Couriel, J M; Lewis, M A; Herrick, A L. Prolidase deficiency and systemic lupus erythematosus. Archives Disease in Childhood 76: 441-444, 1997.
8. Sekiya M, Ohnishi Y, Kimura K. An autopsy case of prolidase deficiency. Virchows Archiv Pathological Anatomy Histopathology 406:1 25-131, 1985.
9. Ogata A, Tanaka S, Tomoda T, Murayama E, Endo F, Kikuchi I. Autosomal recessive prolidase deficiency: Three patients with recalcitrant leg ulcers. Arch Dermatol 117: 689-694, 1981.
10. Milligan A, Graham-Brown RAC, Burns DA, Anderson I. Prolidase deficiency: a case report and literature review. Brit J Dermatol 121: 405-409, 1989.
11. Yasuda K, Ogata K, Kariya K, Kodama H, Zhang J, Sugahara K, Sagara Y, Kodama H. Corticosteroid treatment of prolidase deficiency skin lesions by inhibiting iminodipeptide-primed neutrophil superoxide generation. Brit J Dermatol 141: 846-851, 1999.
12. Arata J, Umemura S, Yamamoto Y, Hagiyama M, Nohara N. Prolidase deficiency: Its dermatological manifestations and some additional biochemical studies. Arch Dermatol 115: 62-67, 1979. 13. Jackson SH, Dennis AW, Greenberg M. Iminodipeptiduria: a genetic defect in recycling collagen; a method for determining prolidase in erythrocytes. Canadian Med Assoc J 113: 762-763, 1975.
14. Bissonnette R, Friedmann D, Giroux JM, Dolenga M; Hechtman P; Der Kaloustian V M; Dubuc R. Prolidase deficiency: a multisystemic hereditary disorder. J Am Academy Dermatol 29(5 Pt 2): 818-821, 1993.
15. Klar A, Navon-Elkan P, Rubinow A, Branski D, Hurvitz H, Christensen E, Khayat M, Falik-Zaccai TC. Prolidase deficiency: it looks like systemic lupus erythematosus but it is not. European J Pediatrics 169(6):727-732, 2010.
16. Viglio S, Annovazzi L, Conti B, Genta I, Perugini P, Zanone C, Casado B, Cetta G, Iadarola P. The role of emerging techniques in the investigation of prolidase deficiency: from diagnosis to the development of a possible therapeutical approach. J Chromatography B, Analytical technologies Biomedical Life Sciences 832: 1-8, 2006.
17. Arata J, Hatakenaka K, Oono T. Effect of topical application of glycine and proline on recalcitrant leg ulcers of prolidase deficiency. Arch Dermatol 122: 626-627, 1986.


Address Correspondence to: Morris T. Haywood, DPM. Ohio College of Podiatric Medicine, 16000 Rockside Woods Blvd N.,Independence, Ohio 44131-2330

1  Ohio College of Podiatric Medicine, 16000 Rockside Woods Blvd N.,Independence, Ohio 44131-2330

© The Foot and Ankle Online Journal, 2011

Gait Efficiency and the Use of Insolia® Flex to Promote First Metatarsophalangeal Joint Dorsiflexion

by Sarah A. Curran, PhD, BSc(Hons), FCPodMed, FHEA , Janette Davis 1, Joanna L. Tozer 1, Laura Watkeys 2

The Foot and Ankle Online Journal 4 (4): 2

Background: Dorsiflexion of the first metatarsophalangeal (MTP) joint during walking is an important characteristic that assists efficient forward progression. In spite of a range of foot orthoses used to encourage motion at this joint, little is known how they influence energy efficiency during walking. The aim of this study was to determine if a mass market, insole modification (Insolia® Flex) influenced energy consumption and improved forefoot comfort.
Materials and Method: Fifteen healthy male volunteers (mean age 29 years) were randomly assigned 2 pairs of identical and commercially available footwear, one of which contained the Insolia® Flex. Heart rate (HR), volume of oxygen consumed in liters per kilogram (VO2/kg), respiration exchange ratio (RER), physiological cost index (PCI) and the number of steps (NoS) were monitored whilst walking on a treadmill at a speed of 4.2km/hour and 0% incline for 20 minutes. The Footwear Comfort Scale was also completed following each condition.
Results: Paired t tests showed that HR, VO2/kg and the PCI were significantly reduced for the Insolia® Flex condition (p<0.001). No significant differences (p>0.05) were noted for the RER (p<0.05), but significantly less NoS were taken during the Insolia® Flex condition (p<0.001). A significantly improved overall and forefoot comfort rating (p<0.001) was noted for the Footwear Comfort Scale.
Conclusions: The findings of this study show that energy consumption measures (i.e. HR and VO2/kg) and the PCI (a proxy measure) are influenced by first MTP joint function and suggests that efficiency is improved with the use of a modified insole that promotes function at this joint. Further research is required to clarify these findings.

Key words: Energy consumption, First metatarsophalangeal joint, First metatarsal, Insolia® Flex, Comfort.

Accepted: March 2011
Published:: April 2011

ISSN 1941-6806
doi: 10.3827/faoj.2011.0404.0002


During human bipedal walking, the storage and exchange of potential and kinetic energy in compliant structures is considered an important energy saving mechanism. [1-3] Approximately 10,000 steps is the target value that should be taken each day by the average person, and is achieved by a style of gait that progresses the body forward in a safe and efficient manner. [4] Whilst numerous and complex mechanisms are involved, the energy provided during subsequent steps is a result of momentum and pulling action of the swinging limb and stability of the stance limb. Critical to achieving this, is hip extension of the swinging limb and adequate dorsiflexion at the first metatarsophalangeal (MTP) joint of the stance limb.

This latter view is based on the reliance of the first MTP joint to engage in a series of autosupport mechanisms (i.e. Hicks windlass, [5,6] high [transverse] propulsion [7,8]) which act in a timely manner during terminal stance to provide stability of the foot for efficient forward advancement of the body. [9-14]

Whilst normal walking requires 65º – 75º of dorsiflexion for efficient forward momentum of the body, the key to understanding the importance of first MTP joint motion is the recognition of first metatarsal function and stability. [15,16] Although the initial 20º of hallux dorsiflexion is achieved without motion of the first metatarsal during stance, to obtain further motion, the hallux relies upon first metatarsal plantarflexion, which couples approximately 1º of plantarflexion for every 3º of hallux dorsiflexion. [17] A dorsiflexed first metatarsal is frequently implicated as a contributing factor to limited mobility of the first MTP joint and include conditions such as functional hallux limitus, hallux limitus and hallux rigidus. This is supported by various forms of foot orthoses that attempt to reposition the first metatarsal (i.e. encourage plantarflexion). [18-21]

Although several studies have shown the kinematic and kinetic improvements of these devices, the effects of these orthoses on energy efficiency are unknown. This is an important omission since normal function at the 1st MTP joint is considered essential for an efficient and fluent gait pattern. Previous studies have shown that methods used to record energy consumption such as volume of oxygen consumed in liters per kilogram (VO2/kg), heart rate (HR), the Physiological Cost Index (PCI) and the frequency of steps taken are responsive allowing differences between various conditions to be determined. [4,22-31] These observations include alterations in high heeled footwear alone; [31-33] high heeled footwear and pre-fabricated foot orthoses, [34] as well as patients with post cerebral vascular accident and rheumatoid arthritis. [35]

The following study attempts to address this imbalance and at the same time explores the influence of a mass market, insole modification – Insolia® Flex. This new product is designed to permit both plantarflexion and eversion of the first metatarsal head during the latter part of the stance phase of walking. The combination of plantarflexion and eversion facilitates improved first metatarsal function and the prevention and development of conditions such as functional hallux limitus and hallux limitus. The aim of this present study therefore was to examine if Insolia® Flex changed energy consumption and improved perceived comfort at the forefoot.

Methods

Participants and materials

A total of 15 male university staff and students volunteered to take part in the study. The mean age was 28.9 years (standard deviation [SD] 7.7, range 19 – 48 years), mean weight of 81.2 kilogram (kg) (SD 14.6, range 57.2 – 105.5 kg), mean height of 171.3 centimeters (cm) (SD 8.2, 158.5 – 190.5cm), and mean shoe size of 7.8 (SD 2.1; range 4.5 – 11.5). Ethical approval was sought from the School of Health Sciences Ethics Committee, University of Wales Institute, Cardiff before the study began. The study’s purpose and procedures was fully explained to each participant. Informed consent was obtained from all participants before taking part.

All participants were screened to ensure they had adequate range of dorsiflexion (extension) at the first MTP joint. Participants with <15º (i.e. hallux rigidus) did not take part in the study. The following inclusion criteria was met for all participants: no reported history of injury to the lower extremity within the last 12 months; no reported history of cardiovascular or neurological problems (i.e. angina, high blood pressure, dizziness); experience of walking on a treadmill; must be able to wear the allocated standardized footwear (female UK sizes 4.5, 5.5, 6.5 or 7.5, and male UK sizes 8.5, 9.5, 10.5 or 11.5). Finally, all participants had to tolerate wearing a mask which covers the mouth and nose (oxygen consumption measurement).

The footwear used in this study was commercially available (Bostonian, USA). (Fig. 1) Two pairs of each available size were provided, and one pair had the Insolia® Flex (Insolia®/HBN Shoe, LLC, Salem, New Hampshire, USA) built within the main insole. (Fig. 2) Insolia® Flex is manufactured as a gel component to approximate the same softness of the plantar fat pad of the foot. Specifically, under the 1st metatarsal head, there is a subtle depression within the device. This is, however, not round, but rather a skewed ovoid, in which the plantar surface is tapered to evert the 1st metatarsal head. The combination of plantarflexion and eversion facilitates improved 1st metatarsal function. In order to blind the process, participants were not informed as to whether they were wearing footwear with or without Insolia® Flex. The order of assessment for each experimental condition was randomly assigned for each participant.

Figure 1 Standardized footwear used in the study.

Figure 2 Example of male insole removed from two identical pairs of footwear. Photo A shows the underside of the insole with the gel component (InsoliaÒ Flex) in situ and photo B illustrates the top surface. Photos A and B provide a visual representation of the underside (C) and topside (D) of the non-modified insole.

Equipment

A Woodway (Desmo, Germany) treadmill was used. The VO2/kg and RER were collected and calculated at one minute intervals using a Metalyzer 3B-R2 (Cortex, Germany). (Fig. 3) The RER is the carbon dioxide (CO2) divided with O2 consumption. HR was monitored using a VFIT monitor (Polarexpress Ltd, London), which was attached to the participant’s chest by a strap. This telemetry system records the electrical signals generated from the heart by the transmitter worn on the chest and displayed on a wristwatch receiver.

Figure 3 Experimental set up showing the treadmill and Metalyzer 3B-R2 used to record HR, VO2/kg and the RER.

A pedometer was used to record the NoS taken (WSG™ Digital Pedometer). The sensitivity of the pedometer was determined using the ‘shake test’ as described by Vincent and Sidman [24] before data collection began. The pedometer was found to be within 3% of the actual number of shakes. The pedometer was positioned according to manufacturer’s instructions, and before data began the step number was cleared.

Footwear Comfort Scale

Following each walking trial the Footwear Comfort Scale [36] was used to determine the perceived comfort for the 2 conditions. This scale has been used by various authors [37,38] and is based on a series of 8 questions that focus on specific areas of the footwear. Perceived comfort is rated using a 15mm visual analogue scale (VAS), with 0 (= 0 comfort point) labeled as ‘not comfortable at all’ and 15 as the ‘most comfortable condition imaginable’ (= 15 comfort points).

Since this current project focused on first metatarsal/ray function, only questions 1 (overall comfort) and 3 (forefoot cushioning) were analyzed. For consistency, each participant was advised not to take into account the style and cosmetics of the footwear during comfort rating. In addition, on completion of both sets of experiments, each participant was asked the following question: Which footwear would you choose if you had to walk all day? (i.e. condition 1 or condition 2).

Procedures

Data was collected in a quiet physiology laboratory set at an ambient temperature in 1 session and lasted approximately 80 minutes. Prior to testing, the order for each experimental condition was randomly assigned to the participant to eliminate order effects. Each participant was given a 5 minute acclimatization period on the treadmill for each of the 2 experimental conditions before data collection began. The speed of walking was standardized to 4.2km/hour with a 0% incline. This speed was chosen since it falls within the mean comfortable speed for females and males. [28,38-40]

Following acclimatization, data were collected over a further 20 minutes at the same standardized speed. To minimize fatigue, each participant was allowed a 10 minute rest between each experimental condition and/or until their HR returned to its resting value. Each participant was instructed to look straight ahead whilst walking on the treadmill. The procedure was terminated if data failed to be recorded or the participant felt uncomfortable, showed an unsteady gait, signaled to stop or when the walking period was completed.

Data and statistical analysis

The mean, SD and range were calculated for all of the measures investigated. The PCI was calculated using the following equation: Walking heart rate – resting heart rate divided by speed (m/min).29 A series of Kolmogorov-Smirnov tests were performed and showed all data to have a normal distribution (p<0.001). All variables were analyzed using paired t test and 95% confidence intervals (CI) to establish differences between each of the two conditions. The software package SPSS® (version 17.0, London, UK) was used to analyze the data and the significance level was set at p<0.05.

Results

Differences: Metabolic variables and efficiency
The mean, SD and range values produced from the male group for HR, VO2/kg, RER, NoS and PCI for each of the experimental condition are summarized in table 1. Significant differences were observed between the two experimental conditions for HR (95% CI -6.26707 to -3.53293; t=-8.000; df 14, p<0.001); VO2/kg (95% CI -1.95845 to -.82155; t=-3.452; df 14; p=0.004), and the PCI (95% CI -.15187 to -.02546; t=-3.009, df 14; p=0.009). It was noted that HR, VO2/kg, and the PCI was reduced by 6.1% (5.3), 9.7% (1.3) and 25.8% (0.08) respectively. A reduction of 6% (4.5 beats/min) for heart rate, 10.6% (1.4 ml/min/kg) for VO2/kg and 20% (0.07) for PCI was noted for the Insolia® Flex condition. Whilst no significant differences were noted for the RER (95% CI -.02964 to .00897; t=.797; df 14; p=0.1219), the NoS taken by males were significantly differently with 7.4% (143 steps) (95% CI 37.11719 to 248.11719; t=2.898; df 14; p=0.012) increase noted for the Insolia® Flex condition.

Table 1 Mean, SD and range of each condition and variable measured for the male group (*significant differences p<0.05, paired t test).

Footwear Comfort Scale

Significantly higher rating values were noted for the male group for ‘overall comfort’ (95% CI .50693 to 4.29307; t=2.719, df 14, p=0.017) and forefoot cushioning (95% CI 1.31402 to 7.61931; t=3.0339; df 14; p=0.009) for the Insolia Flex® condition. Overall comfort increased by 29.6% (2.4), whilst forefoot comfort showed a higher increase of 49.5% (4.5) Figure 4 illustrates the comparison of perceived comfort ratings for each of the two conditions for the female and male groups. Eleven males chose the Insolia® Flex condition to walk all day (no Insolia Flex®: n = 4). (Fig. 4)

Figure 4 Comparisons for ratings of overall comfort and forefoot rating (Insolia Flex®  ; no Insolia Flex ® ). Indicates significant differences at p<0.05* and p<0.01**).

Discussion

The aim of this study was to investigate if Insolia® Flex changed energy consumption and improved perceived comfort at the forefoot. The findings of this study suggest that traditional measures of energy consumption (i.e. HR and VO2/kg) and a proxy measure (i.e. PCI) are influenced by 1st metatarsal function suggesting that efficiency is improved.

Energy efficiency measures and the number of steps

For this study, a range of energy efficiency variables namely HR, VO2/kg, RER and PCI were analyzed during treadmill walking for a period of 20 minutes. This is a popular method employed by many [34,43,44] and provides a controlled experiment condition (i.e. speed of walking). Whilst treadmill walking could be criticized for being ‘unnatural’, previous evidence does suggest is that walking on a treadmill identical to routine walking. [45] The only difference however comes from air resistance which can be considered as insignificant during normal speed walking. HR, VO2/kg and PCI were all significantly reduced for the Insolia® Flex condition. Whilst direct comparisons cannot be made with other studies due to the nature of the product investigated (Insolia® Flex), the findings of the present study does share similarities with a previous study that showed that insoles can improve energy efficiency. [34]

During level walking at a constant speed, the mechanical work undertaken at the beginning of stride acts to lift the centre of mass (CoM). When the CoM is lowered (referred to as negative work), the potential energy attributable to the rise in the CoM is turned into kinetic energy. [10,13,14,46] Contact of the foot with the supporting surface uses some of this energy to raise the CoM, and can be illustrated as two curves which are symmetrical and out-of-phase. [47] Studies of ‘normal’ weight individuals have shown that walking is less efficient when mass is placed on the lower legs or thighs compared with waist loads. [48] This increase could be due to the mechanical work required to swing the limb forwards which essentially have an increased mass and moment of inertia. [49] In this study, it was found that the Insolia® Flex significantly reduced the NoS. This perhaps was a surprise finding, since a significant reduction in HR, VO2/kg and PCI was observed it was thought that there would be a change in the NoS taken. There could however be a number of reasons for this. For example, the speed of the treadmill for the males which was set at 4.2 km/hour may have been too slow. Nevertheless, the Insolia® Flex condition may have allowed for a longer stride and more efficient (negative energy) phase as more motion was afforded at the 1st MTP joint. This is may have corresponded with enhanced hip extension and initiated an improvement in the foot’s autosupport mechanisms (i.e. Hicks windlass, calcancaneocuboid joint locking).

Perceived comfort and standardized footwear

Perceived overall comfort and forefoot comfort for the Insolia® Flex showed a significant difference. It was noted that the mean comfort value improved from 2.1 to 8.1 for overall comfort, and 4.6 to 9.1 for forefoot comfort. The increase for the latter rating could be due to an increased in space within the forefoot as well as the cushioning effect from the product. Seventy three percent of the males preferred the Insolia® Flex condition.

Limitations of the study and future work

The equipment used in this study was simple and the method employed was clear, however, it is acknowledged that there were inherent limitations. For example, whilst a relatively long period of walking was undertaken to obtain the energy measures (i.e. 20 minutes), the time can be considered as a snapshot, which may not represent an overall picture of efficiency. In acknowledging the limitations previously discussed, future work should be undertaken to clarify the findings presented in this study. For example, it would particularly useful to examine kinematic changes at the hip, knee and ankle with the Insolia® Flex as well as the pressure distribution using an in-shoe plantar pressure measurement system (i.e. Pedar®, Novel, Munich, Germany, GmbH). Moreover, providing a strict inclusion criteria is devised, further inquiry could be undertaken using participant’s own footwear. This should provide a more global understanding of Insolia® Flex, particularly as it will be promoted as a mass market, insole modification. Further work could also explore the use of this new product on individuals who have limited 1st MTP joint mobility (i.e. functional hallux limitus). This could be coupled with walking on a 5% incline on a treadmill to determine the efficiency and influence of Insolia® Flex on high (transverse) gear propulsion, a component of the foot’s autosupport mechanism.

Conclusion

This study set out to explore the differences in energy efficiency and comfort of a mass market, insole modification that improves plantarflexion/eversion of the 1st metatarsal and 1st MTP joint function. The findings revealed that the Insolia® Flex improved efficiency during a period of 20 minutes (HR, VO2/kg, PCI). Although the NoS were only significantly reduced with Insolia® Flex, there are some logical reasons why this may have happened and include the role of stride length and the standardized speed used to collect the data. future work should explore the role of this new modified insole in participants with limited 1st MTP joint dorsiflexion whilst wearing their own footwear.

Acknowledgments

SAC received funding from Insolia (Insolia®/HBN Shoe, LLC, Salem, New Hampshire, USA) to undertake this project.

Competing interests

SAC is the Chief Editor of the Foot and Ankle Online Journal and was removed from the peer review process and editorial decision for this manuscript.

References

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3. Cavagna GA, Thys H, Zamboni A: The sources of external work in level walking and running. Journal of Physiology 1976; 262: 639 – 657.
4. Waters RL, Mulroy S: The energy expenditure of normal and pathological gait. Gait Posture 1999; 9: 207 – 231.
5. Hicks JH: The foot as a support. Acta Anatomy 1955; 25: 34 – 45.
6. Hicks JH: The mechanics of the foot part II: the plantar aponeurosis and the arch. J Anatomy 1954; 88: 25.
7. Bojsen-Moller F: Anatomy of the forefoot, normal and pathologic. Clinical Orthopaedics 1979; 142(July – August): 10 – 18.
8. Bojsen-Moller F: Calcaneocuboid joint stability of the longitudinal arch of the foot at high and low gear push off. J Anatomy 1979; 129(1): 165 – 176.
9. Dananberg HJ: Sagittal plane biomechanics. American Diabetes Association. Journal of Podiatric Medical Association 2000; 90(1): 47-106.
10. Dananberg HJ: Gait style as an etiology to chronic postural pain. Part I. Functional hallux limitus. Journal of Podiatric Medical Association 1993; 83(8): 433- 441.
11. Dananberg HJ: Gait style as an etiology to chronic postural pain. Part II. Postural compensatory process. Journal of Podiatric Medical Association 1993; 83(11): 615- 624.
12. Dananberg HJ: Mechanisms of foot function. Current Podiatric Medicine 1990; 39: 23 – 26.
13. Dananberg HJ: The power of motion. Current Podiatric Medicine 1989; 38(6 – 7): 26 – 27.
14. Dananberg HJ: The action of elastic response. Current Podiatric Medicine 1989; 38(10): 22 – 24.
15. Lichniak J. E.: Hallux limitus in the athlete. Clin Podiatr Med Surg 1997; 14(3): 407-26.
16. Root M, Orien W, Weed J: Normal and abnormal function of the foot, Vol. Vol 2. Los Angeles, 1977 Clinical Biomechanics).
17. Phillips RD, Lidtke RH: Clinical determination of the linear equation of the linear equation of the subtalar joint axis. Journal of the American Podiatric Medical Association 1992; 82: 1 – 20.
18. Scherer PR, Sanders J, Elderidge DE, Duffy SJ, Lee RY: Effect of functional foot orthoses on first metatarsophalangeal joint dorsiflexion in stance and gait. Journal of American Podiatric Medical Association 2006; 96(6): 474 – 481.
19. Roukis TS, Scherer PR, Anderson CF: Position of the first ray and motion of the first metatarsophalangeal joint. J Am Podiatr Med Assoc 1996; 86(11): 538 – 546.
20. Dananberg HJ: Gait, postural pain, and the Kinetic Wedge. Foot and Ankle Quarterly 1994; 7: 1 – 8.
21. Dananberg HJ: The Kinetic Wedge. J Am Podiatr Med Assoc 1988; 78(2): 98a-106.
22. Sienko Thomas S, Buckon CE, Schwartz MH, Sussman MD, Aiona MD: Walking energy expenditure in able-bodied individuals: a comparison of common measures in energy efficiency. Gait Posture 2009; 29(4): 592 – 596.
23. Graham RC, Smith NM, White CM: The reliability and validity of the physiological cost index in healthy subjects while walking on 2 different tracks. Archives of Physical Medicine Rehabilitation 2005; 86(October): 2041 – 2046.
24. Vincent S, Sidman C: Determing measurement error in digital pedometers. Measurement in Physical Education and Exercise 2003; 7: 19 – 24.
25. Hood VL, Granat MH, Maxwell DJ, Hasler JP: A new method of using heart rate to represent energy expenditure: the total Heart Beat Index. Archives of Physical Medicine Rehabilitation 2002; 83: 1266 – 1273.
26. Sawamura TCS, Nakajima FS, Ojima I, et al.: The efficacy of physiological cost index (PCI) measurement of a subject walking with an intelligent prosthesis. Prosthetics and Orthotics International 1999; 23: 45 – 49.
27. Tippett SR, Voight MJ: Functional Progression for Sport Rehabilitation. Champaigne, IL: Human Kinetics, 1995.
28. Snow RE, Williams KR: Effects of gait, posture, and center of mass position in women walking in high heeled shoes. Medical Science Sports and Exercise 1990; 22: S23.
29. Macgregor J: Rehabilitation ambulatory monitoring. In: Kendi R, Paul J, Hughes J, eds. Disability. London: Macmillan, 1979; 159 – 172.
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31. Murray MP, Kory RC, Sepic SB: Walking patterns of normal women. Archives of Physical Medicine Rehabilitation 1970; 51: 637 – 650.
32. Ebbeling CJ, Hamill J, Crussemeyer JA: Lower extremity mechanics and energy cost of walking in high-heeled shoes. Journal of Orthopaedic and Sports Physical Therapy 1994; 19(4): 190 – 196.
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34. Curran SA, Holliday JL, Watkeys L: Influence of high heeled footwear and pre-fabricated foot orthoses on energy efficiency in ambulation. The Foot and Ankle Online Journal 2010; 3(3 (March)): 1 – 11.
35. Steven MM, Capell HA, Sturock RD, Macgregor J: The physiological cost of gait (PCG): a new technique for evaluating non-steroidal anti-inflammatory drugs in rheumatoid arthritis. British Journal of Rheumatology 1983; 22: 141 – 145.
36. Mundermann B, Nigg BM, Stefanyshyn D, Humble R: Development of a reliable method to assess footwear comfort during running. Gait Posture 2002; 16: 38 – 45.
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Address correspondence to: Sarah A. Curran PhD, BSc(Hons), FCPodMed, FHEA. Senior Lecturer, Wales Centre for Podiatric Studies, University of Wales Institute, Cardiff, Western Avenue, Cardiff, CF5 2YB, UK. Email: scurran@uwic.ac.uk; Phone +44 (0) 29 2041 7221.

1 Wales Centre for Podiatric Studies, University of Wales Institute, Cardiff, Western Avenue, Cardiff, CF5 2YB, UK..
2 Centre for Biomedical Sciences, University of Wales Institute, Cardiff, Western Avenue, Cardiff, CF5 2YB, UK.

© The Foot and Ankle Online Journal, 2011

Immediate Ambulation after a First Metatarsophalangeal Joint Fusion using a Locking Plate: Technique and case reports

by Robert M Greenhagen, DPM1 , Shelly A Wipf, DPM1, Adam R Johnson, DPM2,
Patrick J Nelson, DPM3, Nicholas J Bevilacqua, DPM4

The Foot and Ankle Online Journal 3 (4): 2

Purpose: Arthrodesis of the first metatarsophalangeal joint (MTPJ) is a predictable procedure to relieve pain and dysfunction of the first MTPJ. Many fixation techniques have been described. The authors present two cases in which a locking plate was successfully used for first MTPJ fusion. The patients began immediate weight-bearing post-operatively without a delay in union, hardware failure, or malalignment.
Methods: A retrospective chart and radiographic review of a 53 year-old male and a 59 year-old female was performed. Serial radiograph was taken to assess fusion at the arthrodesis site.
Procedures: Cartilage was resected from the head of the first metatarsal and base of the proximal phalanx preserving the curvature of the joint. The joint was placed in the desired position and interfragmental compression was obtained using a cannulated 4.0-millimeter partially threaded screw from proximal medial to distal lateral with all threads crossed the fusion site. A locking plate was then placed on the dorsal aspect of the joint and secured with locking screws proximal and distal.
Results: The patients began ambulating immediately post-operatively with a post-operative shoe. Both patients had successful fusion by 8 weeks with good alignment and intact fixation. Patients returned to regular shoe gear once trabeculation was noted.
Conclusion: These 2 case reports suggest excellent results and immediate ambulation with compression screws and locking plates. This clinical report shows promise in regards to early ambulation using locking plate fixation technique and further studies are encouraged.

Key words: Arthrodesis, first metatarsophalangeal joint, MTPJ fusion, locking plate.

Accepted: March, 2010
Published: April, 2010

ISSN 1941-6806
doi: 10.3827/faoj.2010.0304.0002


Arthrodesis of the first metatarsophalangeal joint (MTPJ) is a predictable procedure to relieve pain and dysfunction of the first MTPJ. The indications for this common procedure include hallux rigidus, rheumatoid arthritis, revision of failed bunion surgery, implant arthroplasty, and Keller procedures, and deformities secondary to neuromuscular disease such as cerebral palsy and poliomyelitis. [1] Fixation techniques vary from crossed Kirschner wires [1], intramedullary Steinman pins [2], intramedullary screws [3-5], crossed lag screws [6], external fixation [7], and plate fixation with interfragmentary screw. [2-8]

Protocols for post-operative ambulation have varied throughout the literature, and there have been numerous reports of early weight-bearing with favorable union rates, albeit most of these studies reported patients ambulating in a rigid post-op shoe or short leg walking cast that eliminated the propulsive phase of gait.2,9-12 To our knowledge, there are currently no reported cases evaluating the use of locking plates for first MTPJ fusion. The purpose of this report is to examine results with immediate ambulation after first MTPJ with compression screws and locking plates.

Case Report 1

A 59 year-old female presented to the foot and ankle clinic with severe pain to the right first MTPJ. She had undergone an Austin bunionectomy previously, and now presented with severely limited and painful joint range of motion. Radiographs were consistent with asymmetric joint space narrowing and degenerative joint disease. (Fig. 1) The patient was informed of the risk, benefits and complications of both the procedure and the new post-operative protocol.

 

Figure 1  Pre-operative radiographs show severe joint space narrowing and sclerotic subchondral changes. (A)  Radiographs at seven weeks show full trabeculation and intact hardware. (B)

Figure 4  The cup portion of the reamer is used first to remove all cartilage from the metatarsal head. (A)

The phalanx is reamed with the cone reamer. By performing the metatarsal head first, more room is made for cumbersome cone reamer. (B) (Illustration by Patrick Nelson, DPM©) 

Informed consent was obtained and the patient underwent a first MTPJ arthrodesis with a compression screw and a four-hole locking plate. Seven weeks after surgery, the patient presented for follow-up in normal footwear with pain free ambulation. Radiographs revealed trabeculation across the fusion site, with good alignment and intact fixation. (Fig. 2)

Case Report 2

A 53 year-old male presented with localized severe pain to his right first MTPJ. The patient had minimal range of motion and radiographs showed significant degeneration and non-uniform narrowing of the joint space. (Fig 2A) The patient exhausted conservative care and desired surgical management. The patient was informed of the risk, benefits and complications of both the procedure and the new post-operative protocol. Informed consent was obtained and the patient underwent a first MTPJ arthrodesis with a compression screw and a four-hole locking plate. (Fig. 2B)

 

Figure 2  Pre-operative radiographs show severe hallux rigidus with diffuse joint space narrowing and flattening of the metatarsal head. (A) Postoperative week eight, osseous union is noted with no signs of hardware failure. (B)

Post-operatively, the patient was placed in a surgical shoe and instructed to ambulate as tolerated. Eight weeks after surgery, the patient presented in normal shoe gear and pain free ambulation. Radiographs showed trabeculation, excellent alignment and intact fixation.

Technique

A dorsal medial incision was made and layered dissection was continued down to the level of the joint. (Fig. 3) Cartilage was resected from the head of the first metatarsal and base of the proximal phalanx preserving the curvature of the joint using a cup and cone reamer. (Fig. 4) The joint was placed in the desired position (slight dorsiflexion and abduction) and interfragmental compression was obtained using a 4.0-millimeter partially threaded cannulated screw. The screw was placed from proximal medial to distal lateral being sure that all threads crossed the joint. (Fig. 5) The alignment of the joint and position of the screw was directly visualized using intra-operative fluoroscopy. The locking plate was placed on the dorsal aspect of the joint and secured with locking screws proximal and distal. (Fig. 6) The wound is closed in layers and a dressing is applied.

Figure 3 A dorsal medial approach is made which allows reaming of the proximal phalanx and first metatarsal head.

 

Figure 4  The cup portion of the reamer is used first to remove all cartilage from the metatarsal head. (A) The phalanx is reamed with the cone reamer. By performing the metatarsal head first, more room is made for cumbersome cone reamer. (B) (Illustration by Patrick Nelson, DPM©)

Figure 5 An interfragmentary screw can be placed from proximal medial to distal lateral. This provides both compression and fixation that does not interfere with the dorsal plate.  We recommend the use of a cannulated screw for simplicity. (Illustration by Patrick Nelson, DPM©)

Figure 6 Dorsal plating of the joint provides rigid fixation of the fusion site.

Patients are placed in a post-operative shoe and instructed to ambulate as tolerated. Patients are transitioned to normal footwear once clinical and radiographic signs of healing are appreciated.

Discussion

Many fixation techniques have been described for first MTPJ arthrodesis. [2-4,6-8,13] The ideal fixation technique for MTPJ arthrodesis should maintain stability and position of the fusion site while osseous union occurs.

A review of the literature favors interfragmentary screw fixation as the strongest construct. Neufeld and colleagues compared memory compression staples, cannulated screws, and a five-hole, one-third tubular plate contoured to fit the arthrodesis site in 21 matched fresh-frozen cadaver specimens. [14]

Each specimen was loaded to failure in a cantilever fashion and an extensometer was used to measure gapping across the arthrodesis site, with failure defined as a 2-mm gap. They found that the crossed cannulated screws and the dorsal plate constructs failed at significantly higher loads than the two compression staples (p<0.029 and p<0.002, respectively). [14] The dorsal plate failed due to bending of the plate in 79% of specimens. While the crossed cannulated screws provided the greatest amount of rigidity, failure occurred when the screw fractured the metatarsal head at the screw-bone interface in all but one specimen.

Curtis and colleagues found interfragmentary screws to be superior to plate fixation due to bending of the plate. [15] They suggested that adding a screw or K wire placed obliquely to the axis of the MTPJ might improve stability. Politi, et al., used synthetic bone models to demonstrate that the most stable technique was an oblique interfragmentary lag screw with a dorsal plate. [16]

There are several problems with conventional plate application. The stability of a plate relies on compression between the plate and the cortical bone, potentially disrupting the periosteal blood supply and inducing porosity of the bone. [17] To apply a screw to a conventional plate, it must be tightened with an axial traction of 1000-2000 Newtons (N), which produces up to 2400 N of friction in a 4-hole plate (co-efficient of friction between metal and bone = 0.4). [18] In addition, plate application to the first MTPJ is fraught with biomechanical disadvantages. The AO (Arbeitsgemeinschaft für Osteosynthesefragen) group recommends that a plate be positioned on the tension side of a bone to create dynamic compression in accordance with the tension band principle.1 In a loaded first MTPJ, the tension side is the convex plantar surface of the joint. Due to the position of the sesamoids, soft tissue structures, and potential complications of plantar incisions, the ideal placement of the plate on the tension side of the joint is not feasible, and the plate must be placed on the concave dorsal or compression side of the joint. Since the plate thus applied cannot supply tension band fixation, it will instead serve a neutralization function to protect the lag screw from shearing, bending, and torsional forces.

The locking plate design overcomes several of the disadvantages of conventional plate fixation and when combined with the use of an interfragmentary lag screw for compression, may provide a construct sufficiently stable to allow early weight-bearing and successful arthrodesis. The screw holes of the locking plate have threads that match the conically threaded undersurface of the screw heads, locking the screw head to the plate and negating the need for the plate to be compressed against the bone, thus minimizing the potential for disruption of the periosteal blood supply. [18,20] The locking mechanism between the screw and the plate prevents toggle and screw back out which may result from micromotion of up to 90% body weight that could be transferred onto the first MTPJ during gait. [21] In addition, the locking properties of the plate and screws render failure impossible unless there is simultaneous pullout of all the screws. [22] Gallentine and colleagues reported the use of locking plate fixation of proximal metatarsal chevron osteotomies, finding that the locking plate was successful in maintaining alignment and position of the first ray in patients who were allowed to bear weight on their heel immediately postoperatively. [23] In a study of synthetic calcaneal fracture models, the stability of plates with locking screws and conventional plates without locking screws was compared. [24] It was shown that the locking plates provided greater stability than the conventional plates with high cyclic loading simulating full weight-bearing.

In an in-vitro study of first metatarsocuneiform arthrodesis, Cohen, et al., argued that one of the shortcomings of the locking plate is that while it is rigid at the screw to plate to bone interface, it provides no compression at the arthrodesis site. [25] The authors of the current case report assert that the addition of the interfragmentary screw at the fusion site allows for compression, obviating the need for compression by the biomechanically disadvantaged plate. In this way, the plate functions to neutralize weight-bearing forces, while avoiding the aforementioned failure at the screw-bone interface by the intrinsic properties of the locking mechanism.

Allowing immediate ambulation after first MTPJ arthrodesis decreases the morbidity of the procedure by reducing disuse atrophy and osteopenia, the risk of deep thrombosis/pulmonary embolism, and inconvenience to the patient. When fixated with adequate internal fixation, the first MTPJ arthrodesis is a stable construct which allows the patient to ambulate immediately postoperatively. This notion has received support throughout the literature. In his early description of first MTPJ fusion in 1952, McKeever recommended weight-bearing in a cut-out shoe at the third or fourth post-operative day, though he noted that he cautioned the patient “very strongly” against placing full weight on the toe for six weeks. [5] Immediate ambulation in a wooden-soled postoperative shoe or short walking boot is the standard of care reported in a major orthopaedic text. [26]

In a retrospective review of 47 first MTPJ arthrodeses, Dayton reported a 100% fusion rate when allowing immediate post-operative ambulation with a standard surgical shoe, restricting weight to the heel or lateral aspect of the foot. [9] A randomized, prospective study of 61 cases found a 97% fusion rate for the early weightbearing group and a 93% fusion rate for the delayed weightbearing group, suggesting no difference in radiographic union or clinical outcome between patients who began ambulating two to four days post-operatively and those who remained non-weightbearing for four weeks. [12] Most authors recommend the use of a post-operative shoe or a CAM boot to eliminate the propulsive phase of gait, thus decreasing the chance for fixation failure. Young and colleagues compared three types of post-operative boots with a fiberglass cast in a cadaver model using strain gauges in the first MTPJ joint and simulated weightbearing. [27] They found that the removable cast boots provided the same, and in one type, even more reduction of force across the arthrodesis site than a traditional fiberglass cast.

The exact amount of force that a first MTPJ arthrodesis site can tolerate before failing is still unknown. The authors recognize that in certain situations, the force to failure may be reduced, such as revision arthrodeses utilizing bone grafts, cases in which less than optimal fixation is achieved, or large patient habitus. In such cases, an early weightbearing protocol may not be appropriate.

Further limitations of this case report include the small number of cases, selection and evaluation bias. The small number is due to the fact that all patients were directly seen by the junior authors. The senior author may have had other patient’s that would have satisfied the selection criteria, but were not included. This may have lead to an unintended selection bias. All patients and radiographs were evaluated by the senior author. Evaluation bias may have also occurred. The patients’ digital radiographs are included to address this concern. While the authors recognize these limitations, we do not advocate a change in the standard of care based solely on limited case studies alone and further studies are needed.

Conclusion

The authors have presented 2 cases of early ambulation following first MTPJ arthrodesis with a successful result using a locking plate with an interfragmentary screw. This clinical report shows promise for first MTPJ with regard to early and immediate ambulation following first MTPJ fusions.

References

1. Yu GV, Shook, JE. Arthrodesis of the first metatarsophalangeal joint. Current recommendations. JAPMA 1994 84(6): 66-80.
2. Smith RW, Joanis TL, Maxwell PD. Great toe metatarsophalangeal joint arthrodesis: a user-friendly technique. Foot Ankle 1992 13(7): 367-77.
3. Hansen ST. Functional reconstruction of the foot and ankle. 2000, Philadelphia: Lippincott Williams & Wilkins. xviii, 525
4. Castro MD, Klaue K. Technique tip: Revisiting an alternative
method of fixation for first MTP joint arthrodesis. Foot Ankle Int 2001 22(8): 687-688.
5. McKeever DC. Arthrodesis of the first metatarsophalangeal joint for hallux valgus, hallux rigidus, and metatarsus primus varus. JBJS 1952 34A(1): 129-134.
6. Turan I, Lindgren U. Compression-screw arthrodesis of the first metatarsophalangeal joint of the foot. Clin Orthop Rel Res 987 (221): 292-295.
7. Harrison MHM, Harvey FJ. Arthrodesis of the first metatarsophalangeal joint for hallux valgus and ridigus. JBJS 1963 45A (3): 471-480.
8. Goucher NR, Coughlin MJ. Hallux metatarsophalangeal joint arthrodesis using dome-shaped reamers and dorsal plate fixation: A prospective study. Foot Ankle Int 2006 27(11): 869-876.
9. Dayton P, McCall A. Early weightbearing after first
Metatarsophalangeal joint arthrodesis: a retrospective observational case analysis. J Foot Ankle Surg 2004 43(3): 156-159.
10. Sage RA, Lam AT, Taylor DT. Retrospective analysis of
first metatarsal phalangeal arthrodesis. J Foot Ankle Surg 1997 36(6): 425-429 (discussion 467).
11. Flavin R, Stephens MM. Arthrodesis of the first
metatarsophalangeal joint using a dorsal titanium contoured plate. Foot Ankle Int 2004 25(11): 783-787.
12. Lampe HIH, Fontijne P, van Linge B. Weight bearing
after arthrodesis of the first metatarsophalangeal joint. A randomized study of 61 cases. Acta Orthop Scand, 1991 62(6): 544-555.
13. Coughlin MJ, Mann RA. Arthrodesis of the first
metatarsophalangeal joint as salvage for the failed Keller procedure. JBJS 1987 69A(1): 68-75.
14. Neufeld SK, Parks BG, Naseef GS, Melamed EA, Schon LC. Arthrodesis of the first metatarsophalangeal joint: a biomechanical study comparing memory compression staples, cannulated screws, and a dorsal plate. Foot Ankle Int 2002 23(2): 97-101.
15. Curtis MJ, Myerson M, Jinnah RH, Cox QG, Alexander I. Arthrodesis of the first metatarsophalangeal joint: a biomechanical study of internal fixation techniques. Foot Ankle, 1993 14(7): 395-399.
16. Politi J, John H, Njus G, Bennett GL, Kay DB. First metatarsal-phalangeal joint arthrodesis: A biomechanical assessment of stability. Foot Ankle Int 2003 24(4): 332-337.
17. Perren SM, Cordey J, Rahn BA, Goutier E, Schneider E. Early temporary porosis of bone induced by internal fixation implants. A reaction to necrosis, not to stress protection? Clin Orthop Rel Res 1988 (232): 139-151.
18. Perren SM. Evolution of the internal fixation of long bone
fractures. The scientific basis of biological internal fixation: choosing a new balance between stability and biology. JBJS 2002 84B (8): 1093-1110.
19. Müller ME, Allgoewer M, Schneider R, Willenegger H. Manual of internal fixation : techniques recommended by the AO-ASIF Group. 3rd Ed. 1991, Berlin ; New York: Springer-Verlag. xxviii, 750.
20. Rüedi TP, Murphy WM. AO principles of fracture management. 2000, Stuttgart ; New York; Davos Platz, [Switzerland]: Thieme; AO Pub. 864.
21. Wyss UP, McBride I, Murphy L, Cooke TD, Olney SJ. Joint reaction forces at the first MTP joint in a normal elderly population. J Biomech 1990 23(10): 977-984.
22. Kim T, Ayturk UM, Haskell A, Miclau T, Puttlitz CM. Fixation of osteoporotic distal fibula fractures: A biomechanical comparison of locking versus conventional plates. J Foot Ankle Surg 2007 46(1): 2-6.
23. Gallentine JW, Deorio JK, Deorio MJ. Bunion surgery using locking-plate fixation of proximal metatarsal chevron osteotomies. Foot Ankle Int 2007 28(3): 361-368.
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Address correspondence to: Robert M. Greenhagen, DPM, UPMC Podiatric Residency Program, Pittsburgh, PA.

Podiatric Residents, UPMC Podiatric Residency Program, Pittsburgh, PA
Podiatric Resident, Hennepin County Medical Center, Minneapolis, MN
Podiatric Resident, Saint Vincent Charity Hospital, Cleveland, OH
Associate Medical Director, Amputation Prevention Center, Valley Presbyterian Hospital, Los Angeles, CA

© The Foot and Ankle Online Journal, 2010

The Vilex® Hemi-Implant: A Retrospective Analysis of 30 Patients in the Treatment of Hallux Rigidus

by David M. Davidson, DPM 1 , Kenneth T. Goldstein, DPM 2, James D. Yakel, DPM 3

The Foot and Ankle Online Journal 2 (10): 3

Background: Multiple surgical procedures have been described for the correction of hallux limitus deformity. A review of the Vilex® hemi-implant procedure for the surgical treatment of hallux limitus is presented. Clinical outcome and patient satisfaction in 30 patients is reviewed. In addition, a review of the patho-physiology and clinical evaluation of hallux limitus is also discussed.
Methods: The authors reviewed, retrospectively, 30 random cases of patients who failed conservative treatment and underwent a 1st metatarsophalangeal joint implant/arthroplasty using the Vilex® hemi-implant. This implant appears to limit some of the more common complications of implant arthroplasty including, but not limited to subluxation, pain and recurrence of deformity. Patients were chosen randomly after at least 12 months elapsed after surgery. Each patient was provided a questionnaire that asked why they chose to have the procedure and also if their symptoms were improved or eliminated after the procedure.
Results: The vast majority of patients were satisfied with the surgical results. Most were able to return to normal shoes and were able to return to activities with significantly less pain.
Discussion: This study represents a one-year clinical evaluation of patients who underwent surgery for symptomatic hallux rigidus using the Vilex® hemi implant technique. In this group of individuals, the outcome measures were good. The majority of patients reported they would undergo the procedure again.

Key Words: Hallux rigidus, hemi-implant, first metatarsophalangeal joint mobility, satisfaction.

This is an Open Access article distributed under the terms of the Creative Commons Attribution License.  It permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. ©The Foot and Ankle Online Journal (www.faoj.org)

Accepted: August, 2009
Published: October, 2009

ISSN 1941-6806
doi: 10.3827/faoj.2009.0210.0003


In 1887, Davis-Colley [1] termed the phrase hallux limitus. Soon after, Cotterill [2] coined the term hallux rigidus.

Hallux rigidus, or degenerative joint disease of the first metatarsophalangeal joint (1st MPJ), is a deterioration of the joint [3] and subsequent ankylosis. This may cause absence of joint motion, resulting in pain and deformity. Numerous etiologies have been attributed to the degenerative process of hallux rigidus, which include elongated first metatarsal [3,4] first ray hypermobility [5,6] metatarsus primus elevatus [7], osteochondritis dissecans [8], and trauma. [9] Conservative techniques such as orthotics, shoe modifications, and steroid injections can be successful in eliminating some pain. If conservative treatment modalities fail, surgical intervention may be necessary.

Multiple orthopedic and podiatric surgical procedures have been described in the literature to address hallux rigidus including joint preservation techniques [10-14], and joint destructive procedures. [15,16,17] The choice of a procedure should be based on the degree of pain, range of motion, activity level of the patient, and surgeon’s preference. Implant arthroplasty is one of many joint destructive techniques to address hallux rigidus. There are certainly many choices available to the surgeon when considering joint replacement. These include the total, hinged silastic implant with grommets, a hemi-silastic implant, a total, two-piece, cobalt chrome implant as well as many variations of a hemi-cobalt chrome implant.

Generally, FDA implanting protocol calls for “cementing” an implant into the phalanx. In over five years of experience and over 200 surgeries performed with the Vilex® CHI, the authors have not found a need for cementing nor have they encountered a dislocated or a loosening of the CHI implant.

Materials and Methods

The authors reviewed, retrospectively, 30 random cases of patients who failed conservative treatment and underwent a 1st MPJ implant/arthroplasty using the Vilex® hemi-implant. Patients were chosen randomly after at least 12 months elapsed after surgery. Each patient was provided a questionnaire that asked why they chose to have the procedure and also if their symptoms were improved or eliminated after the procedure.

Clinical Findings of Hallux Limitus

The most common finding is the gradual onset of pain and limitation of motion in the 1st MPJ. Clinical examination reveals an enlargement of the 1st MPJ dorsally and/or dorsomedially. Palpation of the joint may elicit pain. Early in the process, there may be muscle spasm of the extensor hallucis longus (EHL) tendon. [18] There is typically very limited range of motion (ROM), which may be painful, with or without crepitus.

Plantar flexion range of motion is usually normal. The hallux may be in a fixed plantarflexed position with the interphalangeal joint (IPJ) in a hyper-extended position with keratoses. Soft tissue swelling may be present. If arthritic changes extend into the sesamoid apparatus, the sesamoids may also be tender.

Radiographic Findings

Radiographic changes include first metatarsal head flattening, non-uniform joint space narrowing, osteophytic changes about the first metatarsal head and base of the proximal phalanx, subchondral cysts, and subchondral sclerosis. Metatarsus primus elevatus may be visualized and the proximal phalanx can be positioned plantar to the head of the 1st metatarsal. Regnauld [19] proposed a classification system from developing ankylosis to end stage joint disease:

Grade I:
Functional limitation of first metatarsophalangeal joint dorsiflexion, hallux equinus/flexus, plantar subluxation of the proximal phalanx on the first metatarsal head, metatarsus primus elevatus, functional dorsiflexion of the first metatarsal with weight bearing, no radiographic degenerative changes, hyperextension of the hallux IPJ, or pronatory architecture.

Grade II:
Flattening of the first metatarsal head, osteochondral defect of first metatarsal head, cartilage fibrillation and erosion, pain on end ROM, passive ROM may be limited, mild dorsal prominence, subchondral eburnation, peri-articular lipping of the proximal phalanx, first metatarsal head, and sesamoids.

Grade III:
Severe flattening of first metatarsal head, osteophyte formation, especially dorsally; asymmetric narrowing of joint space, articular degeneration, erosions, crepitus, subchondral cyst formation, pain on full ROM, associated inflammatory flares.

Grade IV:
Obliteration of the joint space, exuberant osteophytosis with loose bodies, less than 10 degrees of ROM, deformity and/or mal-alignment; possible anklylosis and inflammatory flares, local pain as a result of skin irritation or bursitis secondary to underlying osteophytes.Coughlin and Shurnas [20] described a more complete classification system using the amount of dorsiflexion, radiographic changes, and clinical findings:

Grade 0:
Forty to 60 degrees of dorsiflexion and/or 10-20% loss compared to the normal side. No radiographic changes; no pain with only stiffness and loss of motion.

Grade I:
Thirty to 40 degrees of dorsiflexion and/or 20-50% loss compared to the normal side; dorsal osteophyte formation is the main finding with minimal joint space narrowing, peri-articular sclerosis, and minimal plantarflexion.

Grade 2:
Ten to 30 degrees of dorsiflexion and/or 50-75% loss compared to the normal side; diffuse osteophyte formation radiographically, with some flattening of the metatarsal head; with more narrowing and more than ¼ of the dorsal joint space involved and with the sesamoids typically not involved. Clinically, moderate to severe pain and stiffness, and pain occurs just prior to maximum dorsiflexion and plantarflexion.

Grade 3:
Less than 10 degrees of dorsiflexion and/or 75-100% loss compared with the normal side, notable loss of metatarso-phalangeal plantarflexion; radiographic changes are the same as Grade 2 with more narrowing and more than ¼ of the dorsal joint space involved. The sesamoids are either enlarged, cystic, irregular or a combination of all three. Clinically, the pain is more constant and there is significant stiffness at the extremes of range of motion.

Grade 4:
This is the same as Grade 3, from a dorsiflexion and radiographic standpoint. Clinically, there is definite pain at mid-range during passive motion.

Surgical Procedure

A curvo-linear incision is placed on the dorso-medial aspect of the 1st MPJ. Through the same incision, a linear, longitudinal capsulotomy is performed. The capsule is dissected from the head of the metatarsal and base of the proximal phalanx allowing adequate visualization of the MTP. The medial eminence, along with any hypertrophic bone growth and osteophytes, are resected. The base of the proximal phalanx is carefully freed of soft tissue attachments in order to protect the insertion of all intrinsic musculature. Approximately 4-5 mm of bone is then resected from the base, with an osteotomy performed perpendicular to the longitudinal axis of the shaft. The amount of bone removed is twice the thickness of the Vilex® implant to allow adequate decompression of the MPJ joint.

After placing an appropriate sizer over the new end of the proximal phalanx, a guide wire is inserted in the center hole and driven into the bone, making sure the wire is parallel to the long axis of the phalanx and centered therein. The desired implant size is determined by sliding a cannulated sizer over the guide wire. The sizer should sit flush with the resected surface, on the perimeter and not within it. The sizer is removed and the appropriate implant is screwed into the proximal phalanx and the guide wire is removed. (Fig. 1) The implant should be examined in order to ensure that it is flush with the bone. (Fig. 2)

The Vilex® hemi implant procedure allows the surgeon to assess the eventual position the implant before inserting the implant itself. In addition, the implant is screwed into the phalanx without drilling or broaching.

Figure 1  Implant inserted into proximal phalanx over K-wire.

Figure 2  Implant correctly positioned into proximal phalanx.

After a flush with a combination antibiotic/saline solution, the capsule is approximated with 3-0 Monocryl; the subcutaneous tissue is approximated with 4-0 Monocryl and the skin is closed to surgeon’s preference. The surgical site is dressed with sterile compressive dressings.

Postoperatively, the patient is allowed to weight-bear immediately, in a typical, postoperative shoe. Sutures are removed in 10-14 days and most patients are referred to physical therapy for early, range of motion exercises. We have found that when patients ambulate to tolerance and motion exercises are instituted early in the postoperative period, patients respond more favorably.

Results

The patients ranged in age between 40 – 78 years of age and all patients in this study were classified, based on their clinical history, having no major, systemic, medical problems (Table 1) Pre-operatively, 60% were performing moderate to significant exercise programs, 88% related moderate to severe pain that limited their activities, 80% were restricted in the types of shoes they could wear and only 39% did not like the way their foot looked. (Table 2)

Table 1  Hallux rigidus implant pre-operative evaluation.

Table 2  Implant results before and after surgery for patient group.

Post-operatively, 80% related no or slight discomfort, 92% could participate in almost all activities without problems, 100% stated they could wear orthopedic, casual and/or any type of shoe, the majority of the time, only 22% did not like how their foot looked post-operatively, 80% felt they had more motion than pre-operatively and 77% of the patients were pleased with the outcome of the procedure. (Table 3) Of those not pleased, some were still having joint discomfort and some thought it took longer than they expected to recover.

Table 3  Hallux rigidus implant postoperative evaluation.

Discussion

This study represents a one year, clinical evaluation of patients who underwent surgery for symptomatic hallux rigidus using the Vilex® hemi implant technique. In this group of individuals, the outcome measures were good. The majority of patients reported they would undergo the procedure again.

There should be no question that with all patients who present with symptoms due to hallux limitus or hallux rigidus, all methods of conservative care should be exhausted before entertaining thoughts of surgical intervention. A joint destructive technique of any kind should never be presented to the patient as “restoration of the original” or “as good as new”.

The goal should be limited to pain reduction and joint flexibility as opposed to arthrodesis. Steroid injection, anti-inflammatories, physical therapy and/or biomechanical (functional or accommodative) therapy are all possible choices of care. Once it is determined that a joint destructive technique would be beneficial, we have found that the Vilex® hemi-implant is a very useful procedure. The Vilex® Cannulated Hemi Implant (CHI) offers numerous advantages, some but not all are shared by others:

Material – With Vilex®, the surgeon has the option to use either titanium or cobalt-chrome with titanium backing. The titanium is lighter in weight than cobalt-
chrome implants. In addition, titanium does not contain nickel, thereby avoiding the potential of allergic reaction to nickel present in cobalt-chrome. Also, the titanium is less likely to distort magnetic resonance imaging (MRI) should the patient need MRI scanning in the future.

Low Profile – The articular surface is elliptical in shape and its thickness ranges from 1.5 to 2.0 mm. In resecting the base of the proximal phalanx, the surgeon needs to remove between 3-4 mm of bone to provide room for the implant and to decompress the 1st MPJ. This is a major advantage to the patient because the minimal resection preserves the intrinsic structure of the joint and preserves the toe both functionally and cosmetically. In addition, it retains the option for the surgeon to perform arthrodesis or a Keller arthroplasty should the implant fail.

Cannulation – The fact that the implant is cannulated enables the implant to be placed optimally. After inserting a 1.6 mm guide wire, the surgeon can assess the position, orientation of the implant, and the accuracy of the cut. The surgeon can correct any error by simply relocating the guide wire. Once the wire is placed, the surgeon can visualize the final position of the implant through a simple test.

Screw Shaft – The implant shaft is essentially a cannulated screw with tight thread pitch and very generous major to minor diameter ratio. The three screw tips are hand-sharpened so that implanting the implant does not require drilling or tapping. The CHI is the only hemi-implant on the market with this type of shaft.

The majority of patients in this study did have significant improvement in symptoms. We have noted excellent results with substantial reduction in pain and an increase in the range of motion of the 1st MPJ.

References

1. Davies-Colley, MR: Contraction of the great toe in adolescents. Br Med J 1: 728 – 732, 1887.
2. Cotterill JM: Stiffness of the great toe in adolescents. Br Med J 1: 1158 – 1162, 1888.
3. Bingold A, Collins D: Hallux rigidus. J Bone Joint Surg 32B: 214 – 222, 1950.
4. Nilsonne H: Hallux rigidus and its treatment. Acta Orthop Scand. 1: 295 – 303, 1930.
5. Jack EA: The etiology of hallux rigidus. Br J Surg 27: 492 – 497, 1940.
6. Kessel L, Bonney G: Hallux rigidus in the adolescent. J Bone Joint Surg 40B: 668 – 673, 1958.
7. Lambrinudi C: Metatarsus primus elevates. Proc R Soc Med 31: 1273, 1938.
8. Goodfellow J: The etiology of hallux rigidus. Proc R Soc Med 59: 821 – 824, 1966.
9. McMaster MJ: The pathogenesis of hallux rigidus. J Bone Joint Surg 60B: 82 – 87, 1978.
10. Geldwert JJ, McGrath MP, Mancuso JE: Cheilectomy: still a useful technique for grade I and grade II hallux limitus/rigidus. J Foot Surg 31: 154 – 159, 1992.
11. DeLauro TM, Positano RG: Surgical management of hallux limitus and rigidus in the young patient. Clin Podiatr Med Surg 6: 83 – 92, 1989.
12. Feldman RS, Hutter J, Lapow L, Pour B: Cheilectomy and hallux rigidus. J Foot Surg 22: 170 – 174, 1983.
13. Kissel CG, Mistretta RP, Unroe BJ: Cheilectomy, chondroplasty, and sagittal “Z” osteotomy: a preliminary report on an alternative joint preservation approach to hallux limitus. J Foot Ankle Surg 34: 312 – 318, 1995.
14. Selner AJ, Bigdan R, Selner MD, Bunch EK, RL Mathews RL, Riley J: Tricorrectional osteotomy for the correction of late-stage hallux limitus/rigidus. J Med Am Podiatr Assoc 87: 414 – 424, 1997.
15. Laird L: Silastic joint arthroplasty of the great toe: a review of 228 implants using the double-stemmed implant. Clin Orthop 225: 268 – 272, 1990.
16. Wulker N: Arthrodesis of the metatarsophalangeal joint of the large toe. Orthopade 25: 187 – 193, 1996
17. O’Doherty DP, Lowrie IG, Magnussen PA, Gregg PJ: The management of the painful first metatarsophalangeal joint in the older patient. Arthrodesis or Keller’s arthroplasty? J Bone Joint Surg 72B: 839 – 842, 1990.
18. McMaster M: The pathogenesis of hallux rigidus. J Bone Joint Surg 60B: 82 – 87, 1978.
19. Regnauld B: Hallux rigidus. In The Foot pp 345 – 359. Springer-Verlag, 1986
Coughlin MJ, Shurnas PS: Hallux rigidus. Grading and long-term results of operative treatment. J Bone Joint Surg Am 11A: 2072 – 2088, 2003.


Address correspondence to: David M. Davidson, DPM
Email: ddavidsonaapsm.org
3980 Sheridan Drive, Amherst, NY 14226
Phone (716) 839-3930, Fax: (716) 839-2667

1 3980 Sheridan Drive, Amherst, NY 14226
2 3980 Sheridan Drive, Amherst, NY 14226
Phone: (716) 839-3930, Fax: (716) 839-2667
3 36 S. 18th Ave., Ste. H, Brighton, CO 80601
Phone: (303) 659-5950, Fax: (303) 654-0948

Interest Disclosure: The authors have no financial relationship or conflicts of interest with Vilex®, Inc. other than occasional speaking engagements.

© The Foot and Ankle Online Journal, 2009

Hallux Limitus and Dynamic Splinting: A Retrospective Series

by Stanley R. Kalish, DPM, FACFAS1 , F. Buck Willis, PhD2

The Foot and Ankle Online Journal 2 (4): 1

Hallux limitus (HL) is commonly seen following contusions or surgical procedures at the metatarsal joint of the great toe. The purpose of this retrospective study was to examine dynamic splinting for treating HL. Sixty-one cases were examined to measure difference between HL from contusion, bunionectomy, or cheilectomy. After a mean duration of 4.2 weeks in treatment with the metatarsal dynasplint (MDS), there was a significant change for all patients (P<0.0001) with a mean 73% gain in dorsiflexion at the metatarsal joint. The lack of difference between groups (P>0.005) shows the consistent benefit of MDS for HL contracture reduction.

Key words: Hallux limitus, dynamic splinting, first metatarsophalangeal joint

This is an Open Access article distributed under the terms of the Creative Commons Attribution License.  It permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. ©The Foot and Ankle Online Journal (www.faoj.org)

Accepted: March, 2009
Published: April, 2009

ISSN 1941-6806
doi: 10.3827/faoj.2009.0204.0001


 
Onset of Hallux Limitus (HL) commonly affects patients after contusion injuries and after one of the two most common surgical procedures for foot pathologies, a bunionectomy or a cheilectomy. [1-3] HL is a pathology of degenerative arthritis in the first metatarsophalangeal joint (MTJ) of the first toe, or a consequence of a runner’s injury this pathology affects both adolescents and adults. [2-8] The literature consensus has long assumed that pain reduction is a predictable result of properly selected surgical patients, but that improvement in the arc of functional motion about the great toe should not be expected.

Before HL repair with cheilectomy, radiographs typically reveal osteophyte formation in addition to dorsal exostosis, narrowing of the joint space, subchondral sclerosis, and flattening of the metatarsal head. Osteophyte formation is common on the first metatarsal head (both plantar and dorsal sides) causing inflammation, edema, pain, and reduced range of motion (ROM). Action of the hallux requires plantarflexion of the first metatarsal bone, which allows the proximal phalanx to dorsiflexion. This bidirectional hinge action must occur with each step. [8,9] The normal smooth motion of the proximal phalanx over the head of the metatarsal is disrupted leading to painful compression of the phalanx against the head of the metatarsal as the joint is dorsiflexed.

Standard of care for HL includes orthoses, NSAIDs and home stretching exercises, but these protocols have had limited success in regaining range of motion because the stretching was not biomechanically correct and did not have measurable, dynamic tension.

The procedure of utilizing low-load, prolonged-duration stretch has been effective in reducing contracture in similar conditions of reduced ROM [3,12,13]  because it does have biomechanically appropriate alignment with measurable tension. Dynamic splinting used the protocol of low-load, prolonged-duration stretch to achieve significant time at their end range of motion. As the range of motion progresses, the calibrated tension of the dynamic splint is increased to continue stretching at the end range. The purpose of this retrospective cohort study was to examine the efficacy of dynamic splinting for treating HL.

Methods

Patients

Case histories were retrospectively acquired for 61 patients who had been diagnosed with HL which continued following contusion or surgery. These patients were treated for one or more months with dynamic splinting.

Intervention

Patients’ initial introduction to the Metatarsophalangeal Dynasplint System (MDS) [Dynasplint Systems, Inc., Maryland, USA], included customized fitting (patient’s foot size and varying degrees of hallux edema) and training on donning and doffing of the devices. (Fig. 1) Verbal and written instructions were provided throughout the duration of treatment for safety, general wear and care, and tension setting goals based on patient tolerance.

Figure 1   Metatarsophalangeal Dynasplint Extension System.

Each patient was instructed to start wearing the MDS initially for 30 minutes, three times a day while seated at a tension setting of #1 (0.10 foot pound of torque). This frequency, intensity, and duration were for acclimatization to the system. The patients were then instructed to increase each wear by ten minutes each day (i.e. 30 min tid (three times a day, latin for ter in die), 40 min tid, 50 min, tid, 60 min tid), until he/she was comfortable wearing the unit for a total of 3 hours each day.

After each patient was comfortable wearing the unit for a total of 3 hours per day, for three days, the patient was instructed to increase the tension one increment every week until reaching setting #4 (0.7 foot pounds of torque). If excess fatigue followed a session (soreness for more than 15 minutes) the patient was instructed to decrease the tension one half a setting for two days until comfortable wearing for 60 minutes per session and then recalibrate at the higher setting. Tracking of patient compliance was accomplished with a dairy, which was submitted to the attending clinicians monthly.

Statistics

The dependent variable in this study was the change in dorsiflexion at the metatarsal joint of the great toe, and the independent variables were the patient categories of bunionectomy vs. cheilectomy vs. contusion. Statistical data analysis was accomplished using a one-way analysis of variance (ANOVA) on data collected after one month’s use of the MDS.

Results

After a mean duration of 4.2 weeks, the ANOVA showed a significant change for all groups (N=61, P<0.001, T=30.079, DF=60). However, there was not a significant difference between groups (P>0.05). (Fig. 2)

Figure 2  Changes in MTJ Extension.

Discussion

The cause for postoperative contracture is hypothesized to be due to excess arthrofibrosis and position due to pain. [10] Secondary treatment procedures include surgical realignment as done with the Kalish Osteotomy. If mobility is not regained and pain is not reduced, then arthrodesis is considered as a final salvage procedure. [11] However, a non-invasive procedure for contracture reduction is usually more desirable. A pilot study recently showed the efficacy of dynamic splinting for regaining flexion in the great toe [3], but this is the first study to examine changes in hallux extension, dorsiflexion at the metatarsal joint, following dynamic splinting.

The purpose of this retrospective cohort study was to examine the efficacy of dynamic splinting for treating hallux limitus. Dynamic splinting used as a home therapy, provided an additional 90 hours per month of stretching at end range for each patient. This was accomplished with controlled, calibrated, changeable tension which adapted to gains in ROM, keeping the joint at end range.

Conclusion

This retrospective cohort study showed a statistically significant difference in ROM following use of the MDS (P < 0.0001), with patients gaining a mean 73% increase in dorsiflexion at the metatarsal joint of the great toe in just one month. MDS utilizes a biomechanical adaptation to achieve a physiological change in contracture reduction of the connective tissue. Patients in this study received a mean 90 hours of end range stretching in home therapy resulting in regained ROM, eliminating the need for secondary surgical procedures to reduce the contracture. [11]

References

1. Goucher NR, Coughlin MJ. Hallux metatarsophalangeal joint arthrodesis using dome-shaped reamers and dorsal plate fixation: a prospective study. Foot Ankle Int 27(11):869 – 76, 2006.
2. Hockenbury RT. Forefoot problems in athletes. Med Sci Sports Exerc 31: S448 – 58, 1999.
3. Willis B, John M. Dynamic Splinting Increases Flexion for Hallux Rigidus (Pilot Study). Biomechanics 14(9), pg49 – 53, 2007.
4. Brodsky JW, Baum BS, Pollo FE, Mehta H. Prospective gait analysis in patients with first metatarsophalangeal joint arthrodesis for hallux rigidus. Foot Ankle Int. 28(2):162 – 5, 2007.
5. Talarico LM, Vito GR, Goldstein L, Perler AD. Management of hallux limitus with distraction of the first metatarsophalangeal joint. J Am Podiatr Med Assoc 95(2):121 – 9, 2005.
6. Payne C, Chuter V, Miller K. Sensitivity and Specificity of the Functional Hallux Limitus Test to Predict Foot Function. J Am Podiatr Med Assoc 92: 269 – 271, 2002.
7. Kennedy JG, Chow FY, Dines J, Gardner M, Bohne WH. Outcomes after interposition arthroplasty for treatment of hallux rigidus. Clin Orthop Relat Res 445:210 – 5, 2006.
8. DeFrino PF, Brodsky JW, Pollo FE, Crenshaw SJ, et al: First metatarsophalangeal arthrodesis: a clinical, pedobarographic and gait analysis study. Foot Ankle Int 23(6): 496 – 502, 2002.
9. Canseco K, Long J, Marks R, Khazzam M, Harris G. Quantitative characterization of gait kinematics in patients with hallux rigidus using the Milwaukee foot model. J Orthop Res 30, 1 – 9, 2007
10. Becher C, Kilger R, Thermann H. Results of cheilectomy and additional microfracture techniques for the treatment of hallux rigidus. Foot Ankle Surg (10): 155-160, 2005.
11. Lau JT, Daniels TR: Outcomes following cheilectomy and interpositional arthroplasty in hallux rigidus. Foot Ankle Int 2001 22 (6): 462 – 70, 2001.
12. Hepburn, G. Contracture and Stiff Joint Management with Dynasplint. J Ortho Sports Phys Ther 8 (10): 498 – 504, 1987.
13. Willis B. Dancers restore knee flexion through dynamic splinting. Biomechanics 15 (1), 49 – 54, 2008.

Acknowledgements

The authors thank Dr. Ram Shanmugam, biostatistics professor at Texas State University, San Marcos, TX for performing statistical analysis.

Conflict of Interest

Regarding conflict of interest, no extramural funding was used in this study. Dr. Kalish is an educator for the parent company of Dynasplint Systems and he did not receive any funding for this study. Dr. Willis is employed by Dynasplint Systems, Inc. and has no ownership or stock in this company.

Equipment

Dynasplint® Systems, Inc.
770 Ritchie Highway, Suite W21
Severna Park, MD 21146

SPSS Inc. (Base Statistical System)
233 S. Wacker Drive, 11th floor
Chicago, IL 60606-6307


 
Address correspondence to: F. Buck Willis, PhD
Email: BuckPhD@yahoo.com

1  Atlanta Foot and Leg Clinic, P.A.
2  Texas State University (at the time of this study) and corresponding author. Dynasplint Systems Clinical Research.

© The Foot and Ankle Online Journal, 2009