Tag Archives: foot pain

Pulsed Radiofrequency Combined with Continuous Radiofrequency Ablation for the Treatment of Morton’s Neuroma: A Case Report

Posted on March 1, 2013 | Comments Off on Pulsed Radiofrequency Combined with Continuous Radiofrequency Ablation for the Treatment of Morton’s Neuroma: A Case Report

by Jackson Cohen, MD1emailsm , Sergio Lenchig, MD2emailsmpdflrg

The Foot and Ankle Online Journal 6 (3): 1

Morton’s neuroma is a benign enlargement of the third common branch of the medial plantar nerve resulting in a compression neuropathy. First line treatments usually involve shoe modification, non-steroidal anti-inflammatory medications, stretching, and local corticosteroid injections. If these measures fail, many patients will undergo surgical excision for pain relief. Recently, continuous radiofrequency (CRF) ablation has been used as an alternative to surgery; however, this is the first documented case that describes the use of pulsed radiofrequency (PRF) ablation combined with CRF for the treatment of Morton’s neuroma. A patient with two Morton’s neuromas, located in the second and third webspace of the right foot, was selected. Conservative management was attempted with no improvement before radiofrequency ablation was performed. The second and third web spaces were treated with PRF at 42 degrees for 120 seconds followed by CRF at 90 degrees for 25 to 30 seconds. Following the procedure, the patient’s pain score decreased 100% and her quality of life improved significantly as she was able to enjoy dancing in high-heeled shoes once again. There were no complications after the procedure and the patient reported no pain at the six-month follow up visit. Although surgical excision has been the standard of care for treating Morton’s neuromas when conservative measures fail, PRF combined with CRF ablation may be an effective treatment for relieving pain secondary to this condition.

Key Words: Morton’s Neuroma, Radiofrequency Ablation, Pulsed Radiofrequency, Non-surgical treatment, Foot pain

Accepted: February, 2013
Published: March, 2013

ISSN 1941-6806
doi: 10.3827/faoj.2013.0603.001

Address correspondence to: Fort Lauderdale Pain Medicine, 1930 NE 47th Street Suite 300 Fort Lauderdale, FL 33308. sergiolenchig@yahoo.com

1Resident, Department of Rehabilitation Medicine at the University of Miami Miller School of Medicine, Miami, FL. jcohen2@med.miami.edu
2Voluntary Instructor, Department of Anesthesiology, Division of Pain Medicine at the University of Miami Miller School of Medicine, Miami, Florida. Private practice, Fort Lauderdale Pain Medicine, 1930 NE 47th Street Suite 300 Fort Lauderdale, FL 33308. sergiolenchig@yahoo.com

Morton’s neuroma is a common medical condition of the foot characterized by pain between the toes. It was first identified by Civinini in 1835[1] but later named after Morton who illustrated the pathology in greater detail in 1876.[2]

More recently, it has been described as a benign enlargement of the third common branch of the medial plantar nerve, frequently located between the third and fourth metatarsal heads.[3] This plantar digital nerve usually courses under the transverse intermetatarsal ligament so enlargement of the nerve results in a compression neuropathy.[4] 80% of Morton’s neuromas are seen in women and they are usually diagnosed between the fourth and fifth decades of life.[5,6]

Patients often experience burning pain and parasthesias of their forefoot which are aggravated by walking, especially in high-heeled shoes.[7] First line treatments usually involve shoe modification, non-steroidal anti-inflammatory medications, stretching, and injections with corticosteroids and local anesthetics.[8] Repeated corticosteroid injections into the tight webspaces of the foot should be performed cautiously since it may lead to plantar fat pad atrophy[9] and eventually avascular necrosis. Another non-operative treatment that has been shown to have a high success rate in patients with Morton’s neuromas is alcohol neurolysis under ultrasound guidance.[10] Even though these conservative measures are frequently effective; many patients who do not obtain significant pain relief will elect to undergo surgical excision.

Surgical neurectomy has been established as a viable treatment option with good outcomes for many patients with Morton’s neuromas.[7,11,12] In a long term follow up study performed by Coughlin et al., 85% of the patients who underwent surgical excision were satisfied with the results from the surgery and 65% were pain-free 6 years later.[13] Another study demonstrated that 82% of patients reported excellent or good postoperative results, but 71% still had restrictions with footwear.[14]

Recently, continuous radiofrequency (CRF) ablation has been used as a less invasive method for the treatment of Morton’s neuroma before considering surgical resection. CRF utilizes the electricity generated from a radiofrequency wave to disrupt soft tissue molecules, resulting in frictional heating. When the temperature rises to a certain point, normally higher than 70 degrees Celsius, instant tissue coagulation and cell death occur resulting in destruction of neural tissue.[15] In one retrospective study, 83% of patients with Morton’s neuromas who underwent CRF expressed complete relief of symptoms after one month.[3] Additionally, in a longer term study, 87% of patients who underwent CRF had good results with a 70% reduction in the number of patients progressing to surgery.[8]

Pulsed radiofrequency (PRF) ablation is another type of radiofrequency applied intermittently at lower temperatures as compared to the continuous high heat seen in CRF. A higher voltage is used in PRF that produces a brief rise in temperature followed by elimination of heat at timed intervals. The mean tip temperature remains below the neurodestructive range, which preserves the structural integrity of the nerve16; but it still has ablative effects due to the temperature spikes and/or electrical field.[17,18] PRF may minimize the risk of nerve damage while still providing good clinical outcomes; however, there is limited data supporting this.[19]

By combining PRF with CRF, a shorter duration of CRF can be utilized thus decreasing nerve and tissue damage, while still achieving pain relief through the combined ablative effects. Based on a pubmed/medline search, this is the first documented case that describes the use of pulsed radiofrequency ablation combined with continuous radiofrequency ablation for the treatment of Morton’s neuroma.

Case Report

A 53 year-old woman with a past medical history of asthma presented to an outpatient pain clinic complaining of right foot pain for the past 5 years. The pain was located on the plantar aspect of her forefoot between the third webspace and to a lesser degree between the second webspace. The patient described the pain as sharp, stabbing, throbbing, and tingling in nature. The pain was intermittent, exacerbated with walking and dancing, especially if wearing high-heeled shoes. On a numeric pain scale, her pain reached 10 out of 10 at its maximum and decreased to 0 out of 10 with rest; however, the pain was constant with ambulation. She wore supportive sandals in addition to taking ibuprofen and naproxen over the past few years, but these medications did not provide significant pain relief.

RADMNFig1

Figure 1 Magnetic resonance imaging of the right foot. Dashed arrow indicates Morton’s neuroma located in the third webspace.

The patient was sent for a magnetic resonance imaging (MRI) of her right foot which revealed a prominent third webspace neuroma and a smaller second webspace neuroma with the confirmed diagnosis of two Morton’s neuromas. (Fig. 1) Corticosteroid with local anesthetic was then injected into each neuroma with no improvement in pain. Subsequently, alcohol neurolysis was attempted with some symptomatic relief, but its effects only lasted for one month. The patient was then referred to our pain clinic after receiving each of these treatments.

On physical exam, her right foot did not have any scars, erythema or swelling. There was severe tenderness to palpation over the third webspace, tenderness over the second webspace, and diffuse tenderness when squeezing all of the toes together. No motor or sensory deficits of the right foot were noted and distal pulses were palpable.

As described above, conservative treatment with oral pain medications, shoe modification, local steroid injections, and alcohol neurolysis were all unsuccessful in relieving her pain. Thus, the decision was made to perform PRF combined with CRF ablation for the treatment of her condition as an alternative choice to performing an open neurectomy for removal of the neuroma.

Fig 2

Figure 2 Fluoroscopy of right foot. Needle placed in the third webspace.

Informed consent for radiofrequency ablation of the second and third medial digital branches of the plantar nerve was obtained and the patient was taken to the operating room. She was placed in the prone position and her right foot was prepped with ChloraPrep® and draped with sterile technique. No sedation was used for this procedure. The first needle entry point was identified with the use of a marker needle and fluoroscopy in the AP and lateral views. (Fig. 2) Then, 2ml of 1% lidocaine was infiltrated in the third webspace followed by insertion of a 20-gauge 3-inch radiofrequency ablation needle in the transverse direction.

Fig 3

Figure 3 Fluoroscopy of right foot. Needle placed in the second webspace.

The needle was inserted to the point of initiation of the metatarsophalangeal joint. Sensory stimulation was positive and motor stimulation was negative at this point. Next, 0.5ml of Marcaine® was injected then PRF ablation at 42 degrees Celsius for 120 seconds was performed followed by CRF ablation at 90 degrees for 30 more seconds. This was repeated two more times advancing the needle 1cm each time. For the second webspace, the needle was inserted in the same fashion to the point of initiation of the metatarsophalangeal joint with sensory stimulation positive and motor stimulation negative. Placement of the needle was confirmed with fluoroscopy in the anterior posterior and lateral views. (Fig. 3) Again, 0.5ml of Marcaine® was injected into the webspace then PRF ablation at 42 degrees Celsius for 120 seconds was performed followed by CRF ablation at 90 degrees for 25 more seconds. The patient felt pain at this point so the procedure was aborted and the needles were resected.

Otherwise, the patient tolerated the procedure well with no complications. When the patient returned to the clinic one month later, she reported 100% reduction in pain with no complaints related to the procedure. She was able wear regular shoes and enjoys dancing in high-heeled shoes once again. At the 6 month follow up visit, the patient still reported no pain and was very satisfied with the procedure.

Discussion

As described in this case, PRF combined with CRF for the treatment of Morton’s neuroma is able to provide excellent pain relief while minimizing the neurodestructive effects of CRF. The two prior studies involving CRF for the treatment of this condition utilized longer exposure times of 90 seconds during the procedure thus causing more tissue damage.[3,8] A higher degree of surrounding tissue damage has been shown to be directly related to the rise in temperature and duration of CRF.[20,21] By using PRF prior to CRF, we were able to decrease the exposure time to 30 seconds of CRF, which minimized the amount of destruction to the nervous tissue while still being effective in relieving the pain. In another study, Li et al. demonstrated that when PRF was combined with CRF compared to CRF alone for the treatment of trigeminal neuralgia, there was a decrease in side effects secondary to CRF while the efficacy was preserved.[22]

One of the main benefits of PRF over CRF is that it does not require high temperatures so thermal destruction of nervous tissue does not occur. It has been proposed that PRF produces a very weak magnetic field without any significant biologic effects; however, the active tip of the radiofrequency needle produces an electric field with a very high current density (2 x 104 A/m2).[23] This electric field can induce charges on tissue and distort charged molecular structures, thus disrupting cell function without substantial elevations in temperature.[24] PRF alone has been successful in treating a number of peripheral neuropathies including sural, ilioinguinal, genitofemoral, and suprascapular.[25-27]

Despite these encouraging results, we opted to use PRF combined with CRF for our case of Morton’s neuroma as opposed to only using PRF. By using both types of radiofrequency ablation, we were able to employ each of their different ablative mechanisms[15,17,18] to achieve significant pain relief while minimizing the thermodestructive effects of CRF. Also, as CRF has been documented to be an effective treatment for this condition[3,8], we thought it beneficial to utilize this type of ablation while at the same time using PRF to shorten the duration.

Definitive treatment for Morton’s neuroma has traditionally been a surgical resection via an open neurectomy once conservative measures fail. However, as with many other medical conditions, minimally invasive procedures are becoming more accepted as an alternative prior to surgery. Additionally, many patients are seeking non-surgical treatments in order to avoid the risks associated with open surgeries. Radiofrequency ablation does not require any anesthesia, has minimal recovery time, minute scarring, and less risk of bleeding and infection as compared to larger incisions needed for surgical resection of Morton’s neuromas. Regardless of which type of radiofrequency is performed, the risk of developing complications such as deep space abscesses, hematomas, or stump neuromas as observed by Coughlin, et al., is less than in open neurectomies.[13] Moreover, the potential benefits of complete pain relief after radiofrequency ablation, as seen in this case, make it a practical choice to attempt before considering surgical intervention.

Despite the advantages of using PRF combined with CRF ablation for the treatment of Morton’s neuroma, there are some risks and limitations to this minimally invasive procedure that should be recognized. Correct placement of the needle tip is not only essential to achieving maximal ablative effects on the nervous tissue, but it is also important to avoid injury to non-targeted surrounding tissue. Unintentional thermal destruction by way of CRF can lead to permanent tissue damage in unwanted areas. The use of fluoroscopy to confirm correct placement of the needle may help avoid such complications.

Also, some patients are either not able to remain still during the ablation or tolerate the procedure secondary to pain which may shorten the anticipated duration, thus limiting the efficacy of the treatment. However, our patient achieved 100% pain relief even though the CRF ablation of the second webspace was terminated five seconds early due to pain.

In this particular case, there were no complications during or after the procedure and the patient was extremely pleased with her complete reduction in pain at the 6 month follow up visit. We will continue to use PRF combined with CRF ablation for the treatment of Morton’s neuroma when conservative management fails; however, larger studies with long-term follow up are still needed to confirm the clinical feasibility of this procedure.

Conclusion

Radiofrequency ablation is a minimally invasive procedure that can be used to treat patients with Morton’s neuromas who have failed conservative management. The findings from this case report suggest that PRF combined with CRF is a viable treatment for this condition with certain advantages over CRF alone. This procedure should be considered prior to surgical intervention due to its low risk and potential for complete pain relief; nonetheless, more studies are needed to confirm this.

References

  1. Pisani, G. Sindrome di Givinini-Morton (IIInervodigitalecommune). Tattoo di Chirugia de Piede, ed 2, Edizioni Minnerva Medica, Turin, 1993 505–510.
  2. Morton TG.  The classic. A peculiar and painful affection of the fourth metatarso-phalangeal articulation. Clin Orthop Relat Res. 1979 142: 4-9. [Pubmed]
  3. Moore JL, Rosen R, Cohen J, Rosen B. Radiofrequency thermoneurolysis for the treatment of Morton’s neuroma. J Foot Ankle Surg 2012 51: 20-22. [Pubmed]
  4. Bourke G, Owen J, Machet D. Histological comparison of the third interdigital nerve in patients with Morton’s metatarsalgia and control patients. Aust N Z J Surg. 1994 64: 421-424. [Pubmed]
  5. Bartolomei FJ, Wertheimer SJ. Intermetatarsal neuromas: distribution and etiologic factors. J Foot Surg 1983 22: 279-282. [Pubmed]
  6. Bennett GL, Graham CE, Mauldin DM. Morton’s interdigital neuroma: a comprehensive treatment protocol. Foot Ankle Int 1995 16:760-763. [Pubmed]
  7. Mann RA, Reynolds JC. Interdigital neuroma–a critical clinical analysis. Foot Ankle 1983 3: 238-243. [Pubmed]
  8. Genon MP, Chin TY, Bedi HS, Blackney MC. Radio-frequency ablation for the treatment of Morton’s neuroma. ANZ J Surg 2010 80: 583-585. [Pubmed]
  9. Basadonna PT, Rucco V, Gasparini D, Onorato A. Plantar fat pad atrophy after corticosteroid injection for an interdigital neuroma: a case report. Am J Phys Med Rehabil. 1999 78: 283-285. [Pubmed]
  10. Hughes RJ, Ali K, Jones H, Kendall S, Connell DA. Treatment of Morton’s neuroma with alcohol injection under sonographic guidance: follow-up of 101 cases. AJR Am J Roentgenol 2007 188:1535-1539. [Pubmed]
  11. Valente M, Crucil M, Alecci V. Operative treatment of interdigital Morton’s neuroma. Chir Organi Mov 2008 92: 39-43. [Pubmed]
  12. Monacelli G, Cascioli I, Prezzemolo G, Spagnoli A, Irace S. Surgical treatment of Morton’s neuroma: our experience and literature review. Clin Ter 2008 159: 165-167. [Pubmed]
  13. Coughlin MJ, Pinsonneault T. Operative treatment of interdigital neuroma. A long-term follow-up study. JBJS 2001 83A(9):1321-1328. [Pubmed]
  14. Pace A, Scammell B, Dhar S. The outcome of Morton’s neurectomy in the treatment of metatarsalgia. Int Orthop 2010 34:511-515. [Pubmed]
  15. Ni Y, Mulier S, Miao Y, Michel L, Marchal G. A review of the general aspects of radiofrequency ablation. Abdom Imaging  2005 30: 381-400. [Pubmed]
  16. Podhajsky RJ, Sekiguchi Y, Kikuchi S, Myers RR. The histologic effects of pulsed and continuous radiofrequency lesions at 42 degrees C to rat dorsal root ganglion and sciatic nerve. Spine (Phila Pa 1976) 2005 30:1008-1013. [Pubmed]
  17. Cahana A, Vutskits L, Muller D. Acute differential modulation of synaptic transmission and cell survival during exposure to pulsed and continuous radiofrequency energy. J Pain 2003 4: 197-202. [Pubmed]
  18. Erdine S, Yucel A, Cimen A, Aydin S, Sav A, Bilir A. Effects of pulsed versus conventional radiofrequency current on rabbit dorsal root ganglion morphology. Eur J Pain 2005 9:251-256. [Pubmed]
  19. Lindner R, Sluijter ME, Schleinzer W. Pulsed radiofrequency treatment of the lumbar medial branch for facet pain: a retrospective analysis. Pain Med 2006 7:435-439. [Pubmed]
  20. Chang IA, Nguyen UD. Thermal modeling of lesion growth with radiofrequency ablation devices. Biomed Eng Online 2004 Aug 6: 27. [Pubmed]
  21. Chang IA. Considerations for thermal injury analysis for RF ablation devices. Open Biomed Eng J 2010 4: 3-12. [Pubmed]
  22. Li X, Ni J, Yang L, Wu B, He M, Zhang X, Ma L, Sun H. A prospective study of Gasserian ganglion pulsed radiofrequency combined with continuous radiofrequency for the treatment of trigeminal neuralgia. J Clin Neurosci 2012 19: 824-828. [Pubmed]
  23. Sluijter M, Cosman E, Rittman W. The effects of pulsed radiofrequency fields applied to the dorsal root ganglion – A preliminary report. The Pain Clinic 1998 11:109-117.
  24. Cosman ER Jr, Cosman ER Sr. Electric and thermal field effects in tissue around radiofrequency electrodes. Pain Med 2005 6:405-424. [Pubmed]
  25. Todorov L. Pulsed radiofrequency of the sural nerve for the treatment of chronic ankle pain. Pain Physician 2011 14: 301-304. [Pubmed]
  26. Cohen SP, Foster A. Pulsed radiofrequency as a treatment for groin pain and orchialgia. Urology 2003 61:645. [Pubmed]
  27. Luleci N, Ozdemir U, Dere K, Toman H, Luleci E, Irban A. Evaluation of patients’ response to pulsed radiofrequency treatment applied to the suprascapular nerve in patients with chronic shoulder pain. J Back Musc Rehabil 2011 24:189-194. [Pubmed]

Comments Off on Pulsed Radiofrequency Combined with Continuous Radiofrequency Ablation for the Treatment of Morton’s Neuroma: A Case Report

Posted in Uncategorized

Tagged , , , , ,

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

Posted on November 1, 2012 | Comments Off on 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.

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

Posted in Uncategorized

Tagged , , , , ,

A Rare Case of Os Supranaviculare or Pirie’s Bone in the Pediatric Patient: A Case Report

Posted on October 1, 2012 | Comments Off on A Rare Case of Os Supranaviculare or Pirie’s Bone in the Pediatric Patient: A Case Report

By Mustafa Uslu MD1 , Mehmet Arıcan, MD2 , Beşir Erdoğmuş MD3 

The Foot and Ankle Online Journal 5 (10): 1

Accessory bones of the foot are the variations of the skeletal system. The os supranaviculare (Pirie’s bone) is an accessory bone on the dorsal aspect of the navicular bone located at its midpoint. The patient in this case report has supranaviculare ossicles of the right and left foot. The right foot is symptomatic. This report will alert clinicians concerning atypical and rare dorsal foot pain.

Key Words: Foot pain, accessory bone, os supranaviculare, Pirie’s bone

Accepted: September, 2012
Published: October, 2012

ISSN 1941-6806
doi: 10.3827/faoj.2012.0510.0001

Accessory bones are developmental ossicles and appear as secondary ossification centers fused with the main bone or separated. [1] Most accessory bones do not cause any pain and remain asymptomatic. The incidence is very low. The prevalence of this rare skeletal variation is 1%. [2]

It could be rarely symptomatic and this condition should not be misdiagnosed as a cortical avulsion fracture of the navicular or talar head. [1] Tendinitis or tumors of soft and bone tissue and peripheral neuropathic pain can be considered as a differential diagnosis. Treatment includes both surgical and non-surgical options.

We present a very rare case of a symptomatic os supranaviculare pedis in an 8 year-old school football player. The clinical presentation is described. We declare that differential diagnosis of this condition needs radiographic evaluation as well as clinical history.

Case Report

An 8 year-old school football player presented with dorsal foot pain on the right. The pain had been present for approximately 6 months, but was increasing while he was playing football and was particularly painful when he kicked the ball. With the exception of playing football, there was no remarkable trauma to this region. Palpation of the talonavicular joint and supranavicular area was painful. Forced plantarflexion also caused pain on the dorsal region. There were no signs of inflammation on the dorsum of the foot. Radiologic studies revealed a symptomatic supranavicular accessory bone. The radiographs and the computed tomography (CT) demonstrated an accessory ossicle on the superior part of the navicular bone next to the talonavicular joint. Radiographs of the contralateral foot also revealed an asymptomatic accessory bone on the left. (Fig. 1A and 1B, Figs. 2A and 2B)

Figure 1A and 1B   Radiographic imaging of the right foot (A) and left foot (B).

Figure 2A and 2B  Computed tomography images of right foot. The supranaviculare ossicle is seen on the transverse plane (A) and on the sagittal plane (B).

Conservative treatment including immobilization of the foot by taping, physical therapy and anti-inflammatory medication and target point steroid injection were undertaken. We advised the patient to stop any football activities for a determined period. A significant relief of the pain was observed after conservative treatment. After 2 months follow-up, there were no clinical findings. The patient was offered custom made football shoes for the protection of repeated trauma during football matches.

Discussion

The most common accessory ossicles were accessory navicular (11.7%), os peroneum (4.7%), os trigonum (2.3%), os supranaviculare (1.6%), os vesalianum (0.4%), os supratalare (0.2%), and os intermetatarseum (0.2%). [3] The supranaviculare, called the os talonaviculare dorsale, talonavicular ossicle or Pirie’s bone, is located on the dorsal aspect of the talonavicular joint about the midpoint region of the bone. It has a prevalence of 1% and is a rare skeletal variant. [1] After a trauma of the foot, the normal anatomic variants of accessory bones are often confused with avulsion fractures as an incorrect diagnosis. [1]

In the clinical examination, localization of the pain along this region can indicate the presence of accessory bones. It’s important for the clinician to have knowledge of anatomy about the localization of accessory bones. [4] The important pitfalls in the differential diagnoses between accessory bones and avulsion fractures are the localizations, radiologic imaging of the contralateral foot, cortical continuity, callus formation and regular shapes of the lesion. [4] Kicking the ball with the dorsum of the right foot possibly would make the supranavicular accessory bone symptomatic and aggravated the pain in this case.

Although there was the same anatomic variant on the left side, the pain was absent on the left foot. There was no positive finding of peripheral nerve sensitization differentiated from peripheral neuropathic pain. Also the patient did not give a history of overuse syndromes.

Immobilization of the foot with bandage or tape, anti-inflammatory medication physical therapy should be the first step in treatment. If the pain persists, the second step is to gain more stable immobilization with a cast or splint. Steroid injection on the localized area could be alternative treatment option. Nuclear scintigraphy could help for the symptomatic normal variants. [5] Before radionuclide imaging, magnetic resonance imaging (MRI) or CT can be useful for the correct diagnosis. Surgical excision is a less preferable way of treatment after all other conservative treatments. Surgery may have the best outcome for young patients, although conservative management may be the best way for less active patients. [6] In our case, because of skeletal immature patient we preferred conservative treatment and not surgery.

Conclusion

Symptomatic os supranaviculare is a rare reason for dorsal foot pain in pediatric patient. Differential diagnose is needed. Radiologic imaging is helpful to correctly determine the diagnosis.

References

1. Mellado JM, Ramos A, Salvadó E, Camins A, Danús M, Saurí A. Accessory ossicles and sesamoid bones of the ankle and foot: imaging findings, clinical significance and differential diagnosis. Eur Radiol 2003 13: L164-L177. [PubMed]
2. Gottlieb C, Beranbaum SL. Pirie’s bone. Radiology 1950 55: 423-424. [PubMed]
3. Coskun N, Yuksel M, Cevener M, Arican RY, Ozdemir H, Bircan O, Sindel T, Ilgi S, Sindel M. Incidence of accessory ossicles and sesamoid bones in the feet: a radiographic study of the Turkish subjects. Surg Radiol Anat 2009 31:19-24. [PubMed]
4. Cıllı F, Akcaoglu M. The incidence of accessory bones of the foot and their clinical significance. Acta Orthop Traumatol Turc 2005 39(3): 243-246 . [PubMed]
5. Chiu NT, Jou IM, Lee B, Lee BFYao WJ, Tu DG, Wu PS. Symptomatic and asymptomatic accessory navicular bones: findings of Tc-99m MDP bone scintigraphy. Clin Radiol 2000 55: 353-355. [PubMed]
6. Omey ML, Micheli LJ. Foot and ankle problems in the young athlete. Foot Ankle 1999 31: 470-486. [PubMed]

Address correspondence to: Mustafa Uslu MD
School of Medicine, Düzce University; Department of Orthopedics and Traumatology, 81600, Konuralp/Düzce, Turkey.
Phone: +90 380 542 13 90 / 5778, +90 506 504 04 54 (mobile phone)

1  Department of Orthopaedics and Traumatology, Düzce University, Faculty of Medicine, Düzce, Turkey.
2  Department of Orthopaedics and Traumatology, Düzce University, Faculty of Medicine, Düzce, Turkey.
3  Department of Radiology, Düzce University, Faculty of Medicine, Düzce, Turkey.

© The Foot and Ankle Online Journal, 2012

Comments Off on A Rare Case of Os Supranaviculare or Pirie’s Bone in the Pediatric Patient: A Case Report

Posted in Uncategorized

Tagged , , ,