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A variant of screwless scarf osteotomy for hallux valgus: Clinical and radiographic outcomes

Posted on March 31, 2020 | Comments Off on A variant of screwless scarf osteotomy for hallux valgus: Clinical and radiographic outcomes

by Taoufik Cherrad1*, Hicham Bousbaä1, Mohammed Ouahidi2, Hassan Zejjari3, Jamal Louaste3, Larbi Amhajji4

The Foot and Ankle Online Journal 13 (1): 2

Scarf osteotomy is a versatile procedure for the correction of moderate and advanced hallux valgus. This technique has benefited from many improvements to allow translation and angulation correction of the deformity. We describe in our study a scarf variant without osteosynthesis material in which proximal fixation is made by interlocking and distal fixation with nonabsorbable suture. We retrospectively reviewed 33 feet in 30 patients with an average follow-up duration of 35 months (range: 4-60 months). On the latest follow up, 94 % of the patients were satisfied with the result. American Orthopaedic Foot and Ankle Society (AOFAS) score improved from 56/100 to 87/100. The average improvement of HV angle was from 35° to 12°. The intermetatarsal angle improved from 19° to 7°. The DMAA improved from 27° to 8°. Neither delayed union nor osteonecrosis were observed. This variant of screwless scarf technique gives very good results in severe Hallux valgus by safe and large translation authorizing rotation and supination with low iatrogenicity.

Keywords: hallux valgus, scarf osteotomy, screwless

ISSN 1941-6806
doi: 10.3827/faoj.2018.1301.0002

1 – Orthopaedic surgeon, Military Hospital Moulay Ismail Meknes (HMMIM). Morocco.
2 – Resident in Orthopedic Surgery and Traumatology, HMMIM. Morocco.
3 – Professor in Orthopedic Surgery and Traumatology, HMMIM. Morocco.
4 – Professor Head of the Department of Orthopedic Surgery and Traumatology, HMMIM. Morocco.
* – Corresponding author: taoufikcherrad@gmail.com

Hallux valgus (HV) is the main forefoot deformity. Non-operative treatment may relieve symptoms but the basis of management is surgery. The HV corrective surgery history is marked by various surgical techniques that currently enumerate over 150 procedures [1].

The scarf osteotomy is a powerful and mechanically stable procedure to correct moderate and severe forms of HV. This Z-shaped osteotomy of the first metatarsal was first proposed by Meyer [2]. Weil was the first to use the term ‘Scarf’ [3] and Barouk popularized it in Europe [4]. The scarf osteotomy is very versatile and stable, therefore it allows rotational and translation corrections. Originally this osteotomy was stabilized with two screws. Maestro proposed eliminating the proximal screw by locking the two fragments distally: a notch was created via a medial extension of the cephalic part of the osteotomy, the plantar fragment was displaced laterally, and the distal end of the proximal fragment was then fit into the notch (secondary cut and interlocking joint technique [5]. In 2012, Leemrijse et al optimized this technique to increase the potential range of translation. The procedure consists of distal locking and proximal stabilization without shortening. This was possible by impaction of a corticocancellous bone graft taken from the medial overhanging edge of the proximal fragment [6].

Our study presents the results of a retrospective series involving 33 feet (30 patients) operated for HV according to scarf technique without osteosynthesis material with proximal fixation by interlocking and distal fixation with nonabsorbable suture.

The aim of this study is to evaluate the safety, feasibility, and reproducibility of screwless scarf osteotomy by comparing our clinical and radiographic outcomes to the literature data.

Patients and methods

This is a retrospective study regarding 33 feet of HV from 30 patients treated with Scarf osteotomy without osteosynthesis material and followed in the orthopedic trauma surgery department of the military hospital Moulay Ismail Meknes between January 2014 and December 2018. The average follow-up duration was 35 months (range: 4-60 months). All subjects have given informed consent. Exclusion criteria were; HV treated with other operative techniques than scarf screwless, or a scarf procedure with internal fixation.

Twenty men and ten women had an average age of 37 years (range, 16-65 years) at the time of surgery. Six patients had bilateral HV and only 3 patients have been operated on the two sides by a screwless scarf.   

Pain with irritation at the bunion was present in 29 feet (88%). The unaesthetic deformity was a serious reason for consultation in 14 patients (47%). All of our patients had metatarsalgia and difficulty with shoes wear. Finally, 67% of our feet were Egyptian type (22 cases).

A standardised surgical technique was used in all cases. The foot was positioned on the operative table in spontaneous external rotation position, with a thigh tourniquet inflated to 300 mmHg.

The surgical procedure involves a standard medial incision over the first MTPJ and along the shaft of the first MT. Skin incision is done at the dorsal and plantar skin junction, avoiding to extend too far proximally and stopped distally at about 1 cm from the joint. The dorsal collateral sensitive nerve will be visible and protected. It is normally not necessary to visualise the collateral plantar nerve.

Figure 1 a: The medial capsulotomy with resection of the medial eminence. b: The sesamoid release by medial approach. c: The Z-shaped osteotomy.

After a medial capsulotomy, the medial eminence of the metatarsal head is removed (Figure 1a).

Then, by the same medial approach (Figure 1b). We release and reduce lateral sesamoid according to the Maestro approach; above and under the lateral collateral ligament (LCL) which is respected.

  • Above LCL: to free the extensor hallucis longus (EHL), the fibrous sling is cut.
  • Under LCL: the metatarso-sesamoïd ligament is cut principally with the lateral part of the conjoint ligament close to the base of the phalanx [7] 

The exposure of the plantar aspect of the metatarsal shaft by rugination must respect the soft tissue below the head for blood preservation.

Regarding the scarf osteotomy; the longitudinal section is made along the medial side of M1. The osteotomy begins proximally to 5 mm from the beginning of the proximal plantar exposure and on average at the junction of the dorsal two-thirds and plantar one-third of the shaft. It ends distally at the junction of the dorsal one-third and plantar two-thirds of the head just proximal to the cartilage of the joint (normally approximately 5mm from the joint surface). In the frontal plane, the osteotomy has an oblique direction downwards and outwards. The degree of dorsoplantar slope is chosen to obtain the desired amount of lowering. The saw is directed generally parallel to the metatarsal plantar surface of which has an average inclination from 40° relative to the horizontal; the focus is to respect the lateral beam from the dorsal fragment, which ensures the stability of the osteotomy. The longitudinal cut must be at least 2cm long to eliminate all risk of secondary displacement.

The distal transverse cut is done just behind the dorsal synovial recessus attachment which is respected. This cut is through the distal metaphysis (presence of spongiosa avoids the dorsal fragment to be fit into the distal fragment). The cephalic cut is dorsal and directed from within outward, proximally oblique and angled at 70°or 80° relative to longitudinal limb. If the distal transverse cut is perpendicular to the axis of the second metatarsal, pure translation is achieved and stabilization is required, either via a screw or via interlocking of the two fragments after a secondary cut, which shortens the first metatarsal bone. Finally the position and the obliquity of this distal cut give the osteotomy more stability (Figure 1c). 

The proximal transverse cut is performed, at an angle of 60° relative to the longitudinal limb and perpendicularly to the axis of the second metatarsal bone. A dovetail notch is then created at the proximal part of the plantar fragment to allow interlocking of the proximal plantar part of the osteotomy. This interlocking allows us not to use a proximal screw. This method is mainly used to acquire pure translation without correction of the distal metatarsal articular angle (DMAA). And, as Leemrijse et al recommended, when the DMAA must be corrected, a shorter osteotomy with a greater rotational effect is made and the proximal part of the cut is not impacted, to ensure marked proximal translation. 

After a complete Z cut, we translate easily the lower part of the plantar metatarsal associated with medial rotation which allows to correct the orientation of the metatarsophalangeal cartilage (DMAA).

Figure 2 a: Removal of medial overhanging bone. b: Reshaping and rotation of bony wedge. c: Superior view of screwless scarf osteotomy with a proximal fixation by impaction of bony wedge and distal fixation with nonabsorbable suture through a transosseous tunnel. 

Figure 3 Medial view of first metatarsal showing screwless scarf osteotomy with suture travelling through a transosseous tunnel in distal and proximal stabilisation by interlocking with impaction of the medial overhanging edge.

Once the desired displacement is obtained, the proximal fixation is done by interlocking from the proximal transverse cut, while the distal attachment is held temporarily by a modified Jospin forceps. The 10/10 Kirschner wire is then inserted from top to bottom which will lead the non-resorbable thread N°2 and allows the distal fixation by a transosseous suture under moderate tension avoiding shear of thread in the spongy bone. The medial overhanging wedge of bone is resected and impacted proximally, conferring perfect stability to the construct (Figure 2 and 3). The medial capsulorrhaphy is then performed to center the sesamoid bones which are released by the lateral side.

Figure 4 Postoperative strapping to be kept for 2 weeks.

Primary stability must be compatible with good mobility of the first metatarsophalangeal joint which enables it to maintain satisfying postoperative amplitude. Moreover one patient received an Akin osteotomy of P1 associated with Scarf osteotomy.

Postoperatively, strapping was kept for 2 weeks (Figure 4). Patients were allowed to walk with a Barouk boot for 6 weeks. At week 6, patients were able to walk and stand on the operated foot with full weight bearing.

Patients were assessed preoperatively and postoperatively for clinical and radiological parameters. The clinical evaluation included both subjective and objective assessment with American Orthopaedic Foot and Ankle Society (AOFAS) score. Radiological assessment included IMA (angle M1M2), HV angle (HVA: angle M1P1), DMAA (distal metaphyseal articular angle), angle M1M5 and situation of sesamoids. Measurements were taken with radiographs at weight-bearing dorsoplantar and lateral views.

Statistical analysis was performed using the paired z test to analyze the radiological parameters with the P value set at 0.05 to determine statistical differences.

For the situation of the sesamoids, we used the following classification [8]:

  • Grade 0: no dislocation;
  • Grade 1: lateral sesamoid beyond the lateral border of the first metatarsal;
  • Grade 2: the lateral sesamoid is fully apparent in 1st metatarsal space;
  • Grade 3: both sesamoid bones are located in the 1st metatarsal space.

Results

At the time of the latest follow up (mean: 35 months; range: 4-60 months), 94% of the cases were satisfied and very satisfied with the result (64% very satisfied and 30% satisfied), 6% were not satisfied. 

The average preoperative AOFAS score was 55 (range: 36-71), postoperative AOFAS score was 87 (range: 63-95), 

The average preoperative M1P1 angle of 35.06° (range: 24°-46°) improved to 12° (range: 2° to 22°) postoperatively (p < 0.001). The average reduction of M1P1 angle was 23.06 ° (66% from M1P1 angle

The average preoperative M1M2 angle of 19° (range: 12°- 28°) improved to 7.03° postoperatively (range: 4°-16°; p <0.001).The average reduction of the M1M2 angle was 11.96° (63% from M1M2 angle).

The average preoperative DMAA of 27.27 ° (range: 14 °- 32 °) improved to 8.3° postoperatively (range: 3°-16°; p <0.001).The average reduction of the DMAA was 18.96° (70% from DMAA angle).

Preoperatively the average value of the M1M5 angle was 32.51 ° (range: 20 ° to 42 °). While in postoperative, the average value of the angle M1M5 was 20.57 ° (12 ° to 32 °; p <0.001). The average reduction of the M1M5 angle was 11.93° (22% from DMAA angle).

In preoperatively, the grade 2 was predominant with 22 cases (66.67%) followed by grade 3 with 6 cases (18.18%) and finally the grade 1 with 5 cases (15.15%). 

Authors Procedures M1P1 Angle pre-operative M1P1 Angle post-operative M1M2 Angle

pre-operative

 M1M2 Angle

post-operative

 DMAA

pre-operative

 DMAA

post-operative
Jardé [12] (1996) Soft tissue +/- P1 33.3° 24.5° 14.2° 12°   – –
Coughlin & Carlson [13] (1999) Double osteotomy 34° 12° 15° 6° 23° 9°
Veri [14] (2001) Proximal osteotomy 37° 13° 16° 6° – –
Bauer [15] (2010) Reverdin-Isham Percutaneous Osteotomy 30° 15° 14° 11° 15° 7°
Mahadevan et al [16] (2016) Chevron 32.3° 14.3° 15.2 ° 5.8° 16.5° 8.5°
Our series  Screwless scarf osteotomy 35.06° 12° 19° 7° 27° 8°

Table 1 Anatomical results of several series using different techniques.

  Authors  Pre-operative

M1P1

 Post-operative

M1P1 

 Pre-operative

M1M2

 Post-operative

M1M2

 Pre-operative

DMAA

 Post-operative

DMAA 
Classical

Scarf 

 

 Gayet [17] 37° 21° 15° 10° – –
Crevoisier [18]   32° 17° 16° 10° 13° 10°
Freslon [8]  31.2° 17.5° 12.1° 7.5° 13.3° 11.1°
Lipscombe [19] 31.4° 11° 13° 6° – –
Law Kin-Wing [9] 37.9° 10° 16.1° 8.4° – –
Screwless

Scarf

 

 Leemrijse [6] 38.5° 10.6° 15.1° 8.7° 15.4° 5.4°
Dries Van Doninck [11] 27,9 ° 4,2° 13.5 ° 4.8° – –
Our series  35.06° 12° 19° 7° 27° 8°

Table 2 Radiographic outcomes in the Scarf osteotomy series of the literature.

Authors Year Technique Number of feet Follow-up  Satisfaction Preoperative AOFAS score Postoperative AOFAS score
Veri [14] 2001 Proximal metatarsal osteotomy 37 12.2 years 90% 37 92
Schneider[20] 2004 chevron 112 12.7 years – 46.5 88.8
Freslon [8] 2005 Scarf 123 4.8 years 84.6% – –
Bauer [15] 2009 Percutaneous Reverdin-Isham osteotomy 104 2 years 89% 49 87.5
Leemrijse [6] 2012 Screwless scarf 12 7.7 years 100% – 80
K.-W. Law [9] 2014 scarf 31 17 months 77% – 88
Raymond D. Pollock [21] 2016 Shortening scarf osteotomy 20 25 months 100% 29.2 82.2
Our series 2017 Screwless scarf  33 35.15 months 94% 55 87

Table 3 Comparison of the functional and objectives results of different series.

While in postoperative the grade 0 was found in 18 cases (54%), grade 1 in 13 cases (40%) and grade 2 in 2 patients (6%).

Complications were observed in three patients: Residual pain was reported in two patients (who have been disappointed), while the stiffness of the MP was objectified in one patient. No disorders of consolidation for osteotomy (delayed healing of bone, pseudarthrosis) were noted.

Discussion

Currently, foot surgery requires rapid functional recovery that cannot be conceived without a primary stability and solidity of an osteotomy. Scarf osteotomy is designed to be versatile, authorizing the restoration of multiplanar HV anomaly. It allows horizontal displacement, lengthening, rotation, elevation, and lowering of the MT head [9].

Various modifications of the traditional scarf osteotomy were proposed to improve the biomechanics and to reduce complications. This evolution is motivated by deficiencies and complications of chevron osteotomies, basal osteotomies and Lapidus arthrodesis and by the superiority of scarf osteotomy results compared to these techniques [10] (Table 1).

Many studies have focused on the surgical treatment of hallux valgus by Scarf osteotomy, with or without osteosynthesis material (Table 2). Maestro in 2007 [5] and Leemrijse in 2012 [6] were the first to use the Scarf osteotomy without internal fixation. Leemrijse et al. developed an original technique involving distal locking without shortening and proximal stabilisation by impaction of a cortical-cancellous bone graft [6], whereas in our technique the fixation was ensured  proximally by interlocking and distally by nonabsorbable suture. Compared to other series, our results lead to consider this procedure reliable for correction of the significant hallux valgus (Figure 5 and Tables 1-3).

The screwless scarf osteotomy is a diaphyseal-metaphyseal osteotomy which allows a very wide lateral translation; we don’t need more space for placing a screw which could limit our translation capacity. It also allows sufficient medial rotation to correct the DMAA [5, 6, and 11].

Figure 5 Example of correction of hallux valgus by screwless scarf osteotomy; a: preoperative. b: postoperative.

Figure 6 Scarf osteotomy without internal fixation with 45 days apart, a: preoperative anterior-posterior radiograph. b: Postoperative anterior-posterior radiograph. 

This surgical procedure has clear advantages [6, 11]: 

  • Fewer complications related to screw insertion mostly in porotic bones which can lead to  fragility fracture of  the 1st metatarsal
  • No loss of reduction due to the compressive effect of the screw 
  • Less risk for complications in case of  superficial infection 
  • Less cost because no screw is used

At last, the screwless technique provides high-quality remodeling at the osteotomy site, without stress shielding [6] (Figure 6). The mean follow-up of our series was 35.15 months which is a significant duration for a procedure whose practice is still recent. However, although this period is sufficient to consider the correction for granted, it would be interesting to pursue the follow up of these patients (as in the case of Leemrijse series [6]) to quantify the importance of late recurrence and whether corrections obtained with this procedure are superimposed in terms of efficiency in time to other techniques with an important follow up.

Conclusion

The screwless scarf osteotomy is the favored technique in moderate and severe hallux valgus, on the condition that technique fundamental principles are respected. The absence of screws allows a wide lateral translation and therefore reduces a considerable preoperative metatarsus varus.

Finally in our study, we confirm the efficiency of this recent technique in the treatment of HV with almost 94% excellent and good results in our series. The learning curve of this surgery remains long. Respect and application of various technical artifices is essential for the realization of this economic, reliable and biological procedure.

References

  1. Laffenêtre O, Solofomalala GD, De lavigne C, Bauer T. Hallux valgus : définition, physiopathologie, études clinique et radiographique, principes du traitement. Enc. Med. Chir, 2009 ; 14-1236-A10, 9p. 
  2. Meyer M. Eine neue modifikation der hallux-valgus-operation. Zen Fur Chir. 1926; 53:3265–8.
  3. Weil LS, Borelli AN. Modified Scarf bunionectomy, our experience in more than 1000 cases. J Foot Surg. 1991; 30:609–22.
  4. Barouk LS. Scarf osteotomy for hallux valgus correction: local anatomy, surgical technique, and combination with other forefoot procedures. Foot Ankle Clin. 2000 Sep;5(3):525–58.
  5. Besse JL, Maestro M. Ostéotomie de Scarf du 1er métatarsien. Rev Chir Orthop. 2007; 93:515-23
  6. Leemrijse T, Maestro M, Tribak K, Gombault V, Bevernage BD, Deleu PA. Scarf osteotomy without internal fixation to correct hallux valgus. Orthopaedics & Traumatology: Surgery & Research. 2012 Dec 31; 98(8):921-7.
  7. Maestro M. The ruled lateral release of the metatarsophalangeal and metatarso sesamoïd joint in hallux valgus by the medial approach. Poster EFAS Paris 23-25 octobre 1997.
  8. Freslon M, Gayet LE, Bouche G, Hamcha H, Nebout J. Ostéotomie Scarf  dans le traitement de l’hallux Valgus : à propos de 123 cas avec un recul moyen de 4,8 ans. Rev Chir Orthop. 2005 January; 91:257-266.
  9. Law Kin-Wing, Li Hok-Yin Alwin, Li Pang-Hei, Qunn Jid-Lee, Wai Yuk-Leung. Scarf Osteotomy in Treating Hallux Valgus: Clinical and Radiographical Outcome and Technical Notes. Journal of Orthopaedics, Trauma and Rehabilitation. 2014; 18 (1):22-26. 
  10. Trnka HJ, Mühlbauer M, Zembsch A, Hungerford M, Ritschl P, Salzer M. Basal closing wedge osteotomy for correction of hallux valgus and metatarsus primus varus: 10-to 22-year follow-up. Foot & ankle international. 1999 Mar 1; 20(3):171-7.
  11. Dries Van Doninck et al. Screwless Scarf osteotomy for hallux valgus: evaluation of radiologic correction. Foot and Ankle Surgery. 2017;23 (4): 255–260
  12. Jarde O, Trinquier-lautard JL, Meire P, Gabrion A, Vives P. Hallux valgus traité par ostéotomie de varisation de la première phalange associée à la plastie de l’adducteur. Rev Chir Orthop. 1996; 82:541-548. 
  13. Coughlin MJ, Carlson RE. Treatment of hallux valgus with an increased distal metatarsal articular angle: evaluation of double and triple first ray osteotomies. Foot Ankle Int. 1999 Dec; 20(12):762-70.
  14. Veri JP, Pirani SP, Claridge R. Crescentic. Proximal metatarsal osteotomy for moderate to severe hallux valgus: a mean 12.2 year follow-up study. Foot Ankle Int 2001; 22:817-22.
  15. Bauer T, Biau D, Lortat-Jacob A, Hardy P. Percutaneous hallux valgus correction using the Reverdin-Isham osteotomy. Orthopaedics & Traumatology: Surgery & Research. 2010; 96(4):407-416.
  16. Mahadevan D, Lines S, Hepple S, Winson I, Harries W. Extended plantar limb (modified) chevron osteotomy versus scarf osteotomy for hallux valgus correction: A randomised controlled trial. Foot and Ankle Surgery. 2016; 22:109–113.
  17. Gayet LE, Vaz S, Muller A, Avedikian J, Pries P, Clarac JP. L’ostéotomie Scarf dans le traitement de l’hallux valgus: à propos de 71 cas. Rev Chir Orthop. 1997; 83(suppl II):81.
  18. Crevoisier X, Mouhsine E, Ortolano V, Udin B, Dutoit M. The Scarf osteotomy for the treatment of hallux valgus deformity: a review of 84 cases. Foot Ankle Int. 2001; 22:970-976.
  19. Lipscombe S, Molloy A, Sirikonda S, Hennessy MS. Scarf osteotomy for the correction of hallux valgus: midterm clinical outcome. J Foot Ankle Surg. 2008; 47:273–277. 
  20. Schneider W, Aigner N, Pinggera O, Knahr K. Chevron osteotomy in hallux valgus. Ten-year results of 112 cases. J Bone Joint Surg Br. 2004; 86(7): 1016-20.
  21. Prasad Karpe, Marie C. Killen, Raymond D. Pollock, Rajiv Limaye. Shortening scarf osteotomy for correction of severe hallux valgus. Does shortening affect the outcome? . The Foot. 2016; 29:45-49.

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Post traumatic hallux valgus – a rupture of the medial collateral ligament

Posted on March 1, 2016 | Comments Off on Post traumatic hallux valgus – a rupture of the medial collateral ligament

by Christopher R. Hood JR, DPM, AACFAS1*, Jason R. Miller, DPM, FACFAS2pdflrg

The Foot and Ankle Online Journal 9 (1): 3

Although hallux valgus is often an etiology steeped in biomechanical abnormalities throughout the foot, in rare instances its presence can be due to trauma to the first ray. There are few reports of post-traumatic hallux valgus, none by way of motor vehicle accident. In this instance, a shoed, restrained passenger in a car accident soon thereafter developed this deformity. Suspicion of capsuloligamentous damage was confirmed through MRI. Here we discuss the evaluation and diagnostic tools that help confirm the diagnosis as well as discuss some treatment options.

Key words: capsule tear; hallux valgus; medial collateral ligament; motor vehicle accident; post traumatic

ISSN 1941-6806
doi: 10.3827/faoj.2016.0901.0003

1 – Fellow, Pennsylvania Intensive Lower Extremity Fellowship, Malvern, PA
2 – Fellowship Director, Premier Orthopaedics and Sports Medicine, Malvern, PA and Residency Director, Phoenixville Hospital PMSR/RRA, Phoenixville, PA
Correspondence: Christopher R. Hood JR, crhoodjr12@gmail.com

The deformity of hallux valgus, first described by Carl Hueter in 1871, is characterized by a lateral deviation of the hallux with or without subluxation of the first metatarsophalangeal joint (MTPJ) [1,2]. Etiologies have been documented from equinus of the Achilles, pes planus, neuromuscular disease (cerebral palsy, cerebral vascular accident), posterior tibial tendon dysfunction and rupture, inflammatory (rheumatoid arthritis) [1]. One less common or documented etiology is post traumatic hallux valgus. This has been attributed to medial collateral ligament (MCL) tear, LisFranc injury, turf toe injuries, and medial plantar nerve injury secondary to ankle (tibial) fracture [3-7]. Specifically, tears of the MCL account for only six documented cases in the literature [3,6-8]. Here we describe a post traumatic rupture of the MCL of the first MTPJ after motor vehicle accident (MVA) by a flip-flop wearing restrained passenger, review imaging modalities that can assisted in this diagnosis, and discuss treatment options.

Case Report

The patient, a 21 year old female, presented to our office 8 weeks after being a restrained passenger in a roll-over motor vehicle accident (MVA). There was no loss of consciousness or inability to weight-bear immediately after the accident by the patient. Triaged to a local emergency room, she was diagnosed with a shoulder contusion, facial abrasions, and negative pedal findings despite having some discomfort. Radiographs taken at this institution were negative for any acute trauma. (Figure 1) In the days following the accident, she was still having some discomfort to the left hallux and noticed upon standing that the toe was rotated into a slight valgus orientation (Figure 2). There was also bruising and swelling that persisted for weeks after the injury. Because of this deformity and continued pain and feeling of instability to the toe, greater on weightbearing, she presented to our office for evaluation two months after the date of injury.

Upon physical exam there was a mild amount of edema but no erythema or ecchymosis to the distal-medial foot. Tenderness was mild to the dorsal-medial aspect of the first MTPJ with increased pain on passive dorsiflexion at end range.

Fig1

Figure 1 Radiograph of the patient after initial injury taken in the emergency room. Although non-weightbearing, no valgus rotation is apparent to the hallux. Additionally, there is no evidence of osseous trauma (fracture, avulsions, loose bodies) about the 1st MTPJ.

Fig2

Figure 2 Initial presentation of injury. Notice slight valgus rotation and abduction to the right foot hallux (left) compared to the left foot (right) on weightbearing.

Fig3

Figure 3 Weight-bearing clinical photo transverse plane evaluation. There is no significant difference from right hallux (left) and left hallux (right) in the transverse plane abduction. One can appreciate the slight valgus rotation of the right hallux.

Fig4

Figure 4 Weight-bearing clinical photo for frontal plane evaluation. Note the right hallux (left) has a slight valgus rotation to it compared to the normal left hallux (right).

The patient related no history of bunion deformity or rotation to the toe prior to the injury and the contra-lateral limb demonstrated normal first ray alignment. Clinically, the hallux was noted to be in a slight valgus rotated position in the frontal plane, exaggerated upon weightbearing (Figures 3-4). A very mild abduction of the hallux was appreciated. Mild hypermobility of the first ray was noted bilaterally in equal amounts. Sensorimotor function of the foot was intact. Instability on stress was not noted. Muscle inventory to the joint was within normal limits in dorsiflexion, plantarflexion, abduction, and adduction. The extensor hallucis longus was palpable to its insertion. The radiographs taken immediately after the injury were negative for fracture to the metatarsal, phalanx, or sesamoids.

Fig5

Figure 5 MRI slice T1-Axial (left) and T2-Axial (right) that demonstrates the medial first MTPJ capsuloligamentous tear with discontinuity of the dark capsuloligamentous structures and edema noted on the T2 (right). The lateral capsuloligamentous structures are intact (dark band from lateral proximal phalanx base to metatarsal head) for side comparison on both images.

Fig6

Figure 6 MRI slice (T1, Sagittal) that demonstrates a second MTPJ plantar plate tear. Notice the discontinuity in the dark ligamentous structures along the plantar metatarsal head and base of proximal phalanx where the distal attachment lies.

No malalignment of valgus rotation to the metatarsal, hallux abductus interphalangeus, abduction of the hallux was apparent but these films were limited in being non-weightbearing (Figure 1). An MRI was ordered with suspicion of bone marrow edema or capsular tear and subsequently revealed capsuloligamentous tear to the medial first MTPJ (Figures 5-6). With the diagnosis of MCL/capsule tear made, the patient was sent to physical therapy for six weeks. The hope was to strengthen the ligaments and muscles around the first MTPJ to help correct the position. Over the course of therapy and splinting, little gains were made in correcting the position of the toe. Despite an improvement in pain as the ligaments healed, no improvement to position was noted as the hallux appeared virtually unchanged since the initial presentation

Discussion

The anatomy of the first MTPJ is more complex than the lesser toes, consisting of seven muscles, eight ligaments, and two sesamoids [4]. On either side of the metatarsal head lies the collateral (metatarso-phalangeal) and sesamoid (suspensory) ligaments (Figures 7-8). The collateral ligaments, originating from the medial and lateral metatarsal epicondyle, run distal-plantar towards the insertion at the base of the proximal phalanx while the sesamoid ligament with the same origin, runs more directly plantar to attach to the margin of the sesamoid and plantar plate beneath the metatarsal head [1,7]. Injury to these specific medial ligaments resulting in hallux valgus has only been described six times, first by Douglas et al in 1997, occurring in a professional soccer athlete. Of the remaining five etiologies, injuries were attributed to other soccer injuries, track sprinter injury, the foot being rolled over by truck, and a fall from height [3,6-8]. Each incident had a varying mechanism that caused the injury and therefore pinpointing a common source in order to help prevent recurrence is difficult. However, Coker et al has described three principle mechanisms in acute MTPJ injuries: hyperextension of the joint inducing a lesion of the joint capsule and plantar plate (most common), hyperflexion injury, and valgus force from sudden acceleration [16]. The last mechanism describes this case.

The physical exam should consist of a biomechanical exam of the first ray. Assess the range of motion of the joint, whether the deformity is reducible, position with or without weightbearing, and any laxity in the capsule on stress exam [9]. Perform a valgus stress test to the joint in attempt to reproduce the medial pain or demonstrate a joint laxity. This can also be done under fluoroscopy to assess lateral shift of the proximal phalanx versus the contralateral side [8]. Additionally, due to the patient presenting secondary to a trauma to the foot, assess for any acute edema, ecchymosis, or tender areas to palpation. It is important to evaluate the Lisfranc ligament in addition as injury to this area has been cited to cause a post traumatic hallux valgus [4].

Fig7

Figure 7 Sagittal anatomic visualization of the collateral (metatarsophalangeal) and sesamoid (suspensory) ligaments. Reproduced with permission from Northcoast Footcare [14].

Fig8

Figure 8 Axial anatomic visualization of the soft tissue anatomy of the first MTPJ. Reproduced with permission of Waldrop et al [15].

Further exam points should consist of questioning the patient of any feeling of instability on weightbearing, any previous treatments such as steroid injections, or any recollection of toe deviation (hallux valgus) to a lesser degree prior to the trauma [8].

Radiographs are often the first imaging modality used. As in any trauma situation, initial evaluation should consist of assessing the osseous structures for fracture and the alignment of joints/articulations, abnormalities suggesting ligametous injury. Arthrogram techniques can help further demonstrate any ligamentous tears [8]. High resolution musculoskeletal ultrasound (MSK US) has also been discussed as an initial imaging modality [6]. Magnetic resonance imaging (MRI) or computed tomogram (CT) can be added to assess soft tissue structures or any intra-articular pathology [3]. The collateral ligaments are typically a thin, linear, low-signal intensity structure. With injury one can see MCL thickening and increased signal intensity on MRI T2 or STIR images, best visualized on axial or coronal views, suggestive of sprain. Further, a discontinuity along the capsule or ligaments path suggested tear [3]. This injury has been stated to be best seen on fat-suppressed sequences [3]. For MSK US evaluation, ligaments normally appear hyperechoic (lighter) with uniform thickness and signal. When pathology exists, ligaments demonstrate a hypoechoic (darker) thickening if partially torn or have a hypoechoic gap with heterogenic pattern due to hemorrhage if acutely and completely torn. Chronically torn ligaments remain thickened and on dynamic US evaluation show a laxity in their structure [10,11]. Remember that this technique is highly operator dependent for accurate diagnosis.

In many of the reported cases like the one presented here, the diagnosis of post traumatic hallux valgus was not made at the initial presentation, regardless if the patient was seen immediately or several weeks after the injury. In each of the reported incidents of this injury, the presentation of an acute trauma, medial tenderness, swelling, and ecchymosis were consistent findings. It was not until months later in follow-up after the patient was first evaluated that the hallux valgus was diagnosed. Patients commonly subjectively stated they had noticed a lateral drifting or rotation of the toe and instability in gait after the injury [6,7]. This point is important to remember when evaluating first MTPJ pain that has a specific medial symptomatic component, especially in the immediate timeframe post injury. Index of suspicion should be high for medial capsuloligamentous injury. Treating a medial capsuloligamentous injury should consist of oral anti-inflammatory and immediate institution of short term (4-6 weeks) bracing to allow the medial soft tissue to heal in a rectus and not attenuated position. Bracing can consist of either a hallux valgus splint or hand-moldable silicone putty appliance for the first interspace. Taping techniques to prevent hallux valgus can also be implemented.  A walking fracture boot can also be implemented for additional stabilization or offloading while added institution of non-weight bearing (NWB) can further protect the joint and stresses that weight-bearing adds. Injection therapy should not be attempted as these could weaken then ligaments further [8]. Even if there is no true initial tear and the injury is a mild sprain, daily activities such as walking could secondarily result in further soft tissue deformity, stressing the importance of maintaining proper alignment and consideration for NWB in acute presentation [6].  Literature has not cited the need for immediate surgical intervention in this deformity even if diagnosed acutely [3,6].  It is important to follow a traumatic hallux valgus patient closely with serial physical exams and radiographs to assess progressive deformity [9].

The authors were not able to find a specific therapy regimen for capsuloligamentous tears to the first MTPJ. There is an abundant amount of literature regarding rehabilitation for first MTP joint injuries and plantar plate, turf toe related injuries that could be called upon in treating and rehabbing a lateral capsule tear. These injuries all share the common goal in initial edema control and decreasing pain to performing exercises to help strengthen the ligaments and muscles around the joint and use of modalities to break up scar tissue [12].

When indicated, surgical treatment should consist of addressing the primary etiology. This is often based on the mechanism of injury, whether strictly soft tissue or osseous trauma resulted in deformity. Medial collateral direct repair and reefing or plication of the medial joint capsule is often a main component of any repair [6,7,13]. Correction of an underlying hallux valgus may be beneficial to decrease potential post-operation stress and degeneration to the medial soft tissue repair [8]. Evaluation of the joint should also be performed for any intra-articular pathology, especially in the setting of significant pain with mild deformity. First MTPJ pain has been reported in 43.8% of patients with non-traumatic hallux valgus and this figure is assumed to be much higher in the traumatic setting [3]. To relieve joint pain, potential interventions can include arthroscopy, loose body removal, synovectomy, osteochondral lesion excision with microfracture, decompression osteotomies, or subchondroplasty [3]. Choice of surgery should be based on patient functional level with soft tissue procedures on athletes and add osseous procedures to the average functioning patient [8].

Here, the valgus rotation of the toe was not seen until 8 weeks after the injury, being missed on initial evaluation in the emergency room post-accident. At the first visit to our office, splinting was instituted to prevent further deformity. Although we could not prevent the hallux valgus (as it was an immediate consequence of the injury), little progression was noted across the months of follow-up. Physical therapy was attempted for six weeks, but ultimately no healing of the medial ligamentous in a more native position occurred and the patient desired surgical correction at a later point in time.

Conclusion

In reviewing these injuries, one should first off have an understanding of the anatomy about the first MTPJ to appreciate what capsuloligamentous or tendon structures might be damaged to create the presenting deformity. Secondary, the clinician should hone in on the suspected anatomic location of insufficiency in evaluating studies like radiographs, MSK US, or MRI. In radiographs, one should evaluate for any fractures or bony avulsions, insinuating potential ligamentous damage, while on MSK US or MRI looking for discontinuity of capsuloligamentous structures around the MTPJ. This disruption is akin to evaluating for a MTPJ plantar plate tear, attempting to identify a break in the low intensity (T1 and T2) capsule. On MSK US, hypoechoic signal with or without a discontinuation (representing a tear) along with heterogenous hemorrhage signal are common ligament or capsular tear findings.

With acute injuries to the first MTPJ that have negative osseous trauma, one should still perform a thorough soft tissue evaluation and assess the areas of maximal tenderness with any concomitant erythema, edema, or ecchymosis. If there are positive findings of medial joint pain, the clinician should suspect medial soft tissue damage and should be treated like any sprain with the appropriate bracing and subsequent physical therapy. Care should be taken to protect the medial structures during the healing process to prevent long term deformity. This can be accomplished by hallux valgus taping techniques or pre-made splints, spacer in the first interspace, or CAM boot. If deformity does occur with biomechanical insufficiencies and pain, surgery can be offered in an attempt to realign the first ray and decrease pain to the joint.

References

  1. Coughlin MJ, Anderson RB. Hallux valgus. In: Mann’s Surgery of the Foot and Ankle. Vol 9th ed. Philadelphia: Elsevie Saunders; 2014:155.
  2. Prasitdumrong I, Rungprai C, Reeboonlarb N, Poonpracha T, Phisitkul P. Severe degeneration of the medial collateral ligament in hallux valgus: a histopathologic study in 12 consecutive patients. Iowa Orthop J. 2013;33:54-57. http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=3748892&tool=pmcentrez&rendertype=abstract. (PubMed)
  3. Lui TH. First metatarsophalangeal arthroscopy in patients with post-traumatic hallux valgus. Foot. 2015:1-7. doi:10.1016/j.foot.2015.07.009. (PubMed)
  4. Bohay DR, Johnson KD. The traumatic bunion. Foot Ankle Int. 1996;17(7):383-387. (PubMed)
  5. Johal S, Sawalha S, Pasapula C. Post-traumatic acute hallux valgus: a case report. Foot. 2010;20(2-3):87-89. doi:10.1016/j.foot.2010.05.001. (PubMed)
  6. Fabeck LG, Zekhnini C, Farrokh D, Descamps P-Y, Delincé PE. Traumatic hallux valgus following rupture of the medial collateral ligament of the first metatarsophalangeal joint: a case report. J Foot Ankle Surg. 2002;41(2):125-128. doi:10.1016/S1067-2516(02)80037-0. (PubMed)
  7. Douglas DP, Davidson DM, Robinson JE, Bedi DG. Rupture of the medial collateral ligament of the first metatarsophalangeal joint in a professional soccer player. J Foot Ankle Surg. 1997;36(5):388-390. doi:10.1016/S1067-2516(97)80042-7. (PubMed)
  8. Lohrer H. MP I joint giving way – a case study. Foot Ankle Int. 2001;22(2):153-157. (PubMed)
  9. Kadakia AR, Molloy A. Current concepts review: traumatic disorders of the first metatarsophalangeal joint and sesamoid complex. Foot Ankle Int. 2011;32(08):834-839. doi:10.3113/FAI.2011.0834. (PubMed)
  10. Jacobson JA. Ankle, foot, and lower leg ultrasound. In: Fundamentals of Musculoskeletal Ultrasound. Vol 2nd ed. ; 2012:323.
  11. Rogers CJ, Cianca J. Musculoskeletal ultrasound of the ankle and foot. Phys Med Rehabil Clin N Am. 2010;21(3):549-557. doi:10.1016/j.pmr.2010.06.002. (PubMed)
  12. Faltus J, Mullenix K, Moorman CT, Beatty K, Easley ME. Case series of first metatarsophalangeal joint injuries in division 1 college athletes. Sport Heal A Multidiscip Approach. 2014;6(6):519-526. doi:10.1177/1941738114527546. (PubMed)
  13. Lui TH, Chan KB. Technical tip: reconstruction of medial collateral ligament in correction of hallux valgus deformity with primary medial collateral ligamentous insufficiency. Foot Ankle Surg. 2012;18(1):66-73. doi:10.1016/j.fas.2011.01.005. (PubMed)
  14. Dobrowolski C. Big toe joint anatomy. Northcoast Footcare. 2015. http://www.northcoastfootcare.com/pages/Anatomy-Great-Toe-Joint.html. Accessed September 26, 2015.
  15. Waldrop NE, Zirker C a., Wijdicks C a., LaPrade RF, Clanton TO. Radiographic evaluation of plantar plate injury: an in vitro biomechanical study. Foot Ankle Int. 2013;34(3):403-408. doi:10.1177/1071100712464953. (PubMed)
  16. Coker TP, Arnold JA, Weber DL. Traumatic lesions of the metatarsophalangeal joint of the great toe in athletes. Am J Sports Med. 1978;6(6):326-34. (PubMed)

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Can we recreate intraoperative weight bearing in hallux valgus surgery? A radiographic study using a reproducible technique of load bearing to simulate weight bearing

Posted on March 31, 2014 | Comments Off on Can we recreate intraoperative weight bearing in hallux valgus surgery? A radiographic study using a reproducible technique of load bearing to simulate weight bearing

by RS Ahluwalia1, C Elliott, MS Hennessy1, SR Platt1pdflrg

The Foot and Ankle Online Journal 7 (1): 2

Introduction: Correction of the hallux valgus angle, intermetatarsal angle and sesamoid subluxation in hallux valgus surgery is key to restoring normal joint biomechanics. This is difficult to judge accurately intraoperatively as the foot is not weight bearing. We examine the reproducibility of a simulated weight-bearing test on intraoperative images.
Methods: This is a prospective study of 20 patients undergoing a scarf osteotomy for hallux valgus. All patients were operated by one fellowship trained surgeon and were excluded if they had inflammatory arthropathy. At the time of surgery, two intraoperative images were taken after surgical correction. A standard positional anterior posterior (AP) image was taken followed by a reproducible simulated weight bearing view (i.e. load bearing view). A retrospective review of 6 week and 4-6 month weight bearing images was conducted to assess any measurable differences in a separate group of patients.
Results: The mean preoperative HVA was 30.7, IMA was 14.5, sesamoid position was 5.6. On completion of surgical correction the HVA was 6.6, IMA was 7.2 and sesamoid position was 1.8. On simulated weight bearing with an average of 131.2N (range 98.9-163.5N), the HVA was 8.9, IMA was 10.7 and sesamoid position was 2; this was a closer approximation to the 6-week weight bearing view in all indices recorded. No observed difference was noted between 6 week and 3-6 month weight bearing images.
Conclusions: We have found that our standardized simulated load bearing intraoperative view will yield reproducibility and is a good surrogate marker for the 6-week weight-bearing radiograph. We believe locking the ankle joint will avoid rotation of the foot and allow for an accurate evaluation of final correction (HVA, IMA, and sesamoid position) and aid meaningful evaluation of surgical technique. However, it does not represent a final united position therefore we could not recommend its use in isolation.

Keywords: hallux valgus, scarf osteotomy, basilar osteotomy, radiography, sesamoid

ISSN 1941-6806
doi: 10.3827/faoj.2014.0701.0002

Address correspondence to:1RS Ahluwalia
Email: Footsurgeon7@gmail.com

Hallux valgus is one of the most common chronic foot complaints [1]. Surgical correction involves a soft tissue release and reconstruction combined with an osteotomy.

The scarf osteotomy is a complex procedure and has many important steps with a learning curve. As a consequence the time taken to master the nuances of surgical technique may prove lengthy with the potential for difficulties and complications along the way [2]. Technical success is defined by correction of hallux valgus angle (HVA), intermetatarsal angle (IMA) and sesamoid position and patient satisfaction.

fig 1 Fig 2

Figure 1 and 2 This positional image taken with the foot pressed flat on the image intensifier housing of the C-arm for both positional (Figure 1 – top) and maximal ankle dorsiflexion views (Figure 2 – bottom).

Only one paper has evaluated the use of intraoperative radiography [3]; it highlighted the difficulty in obtaining standardized images. We have observed that non-weight bearing post-operative images show the position of implanted metal work and may provide a guide to correction but do not show absolute mechanical alignment.

figure 3

Figure 3 An illustration of how the load-bearing image was taken with the foot placed on the scale and then placed in to a talar neutral and ankle dorsiflexed. To assess actual force we placed a weight scale to record the crude reaction force produced on maximal dorsflexion of the foot pre- operatively.

We therefore hypothesize that a standardized intraoperative load bearing view could provide a better approximation to the final weight bearing correction. If this hypothesis were to be correct then one would expect this view to be an improvement on a non-weight bearing early intraoperative and postoperative image.

The purpose of this study was to compare the effects of an intraoperative simulated load bearing view to that of a simple foot positioning AP view to assess correction. Both images were then reviewed in comparison to the final weight-bearing image at 6 weeks. An assessment was made as to which of the two views better approximated the final weight-bearing image. A further assessment of adequacy of the 6-week view was made in comparison to 3 – 6 month weight bearing views.

fig 4 non loaded image faoj fig 4b loaded image FAOJ

Figure 4 example of positional (4a) vs. load bearing (4b) images taken in theatre where the soft tissue repair was revised to ensure adequate hallux valgus correction.

Materials and Methods

After internal ethical approval and appropriate consent; consecutive patients operated for hallux valgus were included, conducted by the fellowship-training surgeon (RSA). The operation performed in all cases was a scarf osteotomy plus or minus an Akin osteotomy. The patients were reviewed at 2 weeks postoperatively for a dressing change and wound check. They were seen again at 6 weeks for final weight bearing radiographs.

Intraoperative Radiographic Technique

Images were taken after fixation of the scarf osteotomy and medial capsular repair. All patients had a positional AP intraoperative image as per Elliot et al [3] standard technique. This positional image was taken with the foot placed flat on the image intensifier housing of the C-arm (Figure 1). To produce simulated weight bearing the foot was held in talar-neutral and the image intensifier was raised until maximal ankle dorsiflexion was achieved (Figure 2). In doing this, the simulated pressure was being maximally taken up by the forefoot.

To make an assessment of the force applied when the foot was in this position we placed a single weighing scale to record a maximal amount of reaction force produced on maximal dorsiflexion of the foot preoperatively (Figure 3). The force was calculated in Newtons. A surgeon not involved in the care of the patients made radiographic measurements of the radiographs (C.E.). The images were examined on our PACS system and the intermetatarsal angle (IMA), the hallux valgus angle (HVA), medial sesamoid position was recorded, using the 7 degrees of displacement described by Hardy and Clapham (positions 1–3 normal) [4].

A further retrospective analysis was undertaken by C.E. of 6-week weight bearing radiographs from our hallux valgus data base of patients whom had further radiographs taken at 12 – 24 weeks post-surgery. This additional analysis was done in order to assess the adequacy and validity of 6-week weight bearing radiographs as a surrogate marker for final radiographic outcome.

Statistical Analysis

To determine the accuracy of the fluoroscopy films we compared the two intraoperative images with each other and then finally with the 6-week postoperative radiographs. Further analysis of 6-week weight bearing radiographs and 12-24 week radiographs was undertaken separately. Statistical analysis was achieved with a paired t-test to evaluate the difference between measurement and a Shapiro-Wilk test to evaluate the distribution of measurements with p values less than 0.05 defined as significant.

Results

Twenty-two consecutive scarf osteotomies were undertaken for hallux valgus in 20 patients; 2 required an Akin osteotomy, all were included in final analysis. There were 18 females (2 bilateral cases) and 2 males with an average age of 56.2 years.

For the first 10 cases we measured the weight as surrogate for the reaction force produced on maximal dorsiflexion of the foot. We found that the mean pressure generated was 131.2N (range 98.9-163.5N; Table 1). Intraoperative images were taken on completion of surgical correction and on two separate occasions intraoperative images led the surgeon to make an alteration in the soft tissue tensioning to ensure sesamoid correction.

  HVA IMA Position Load
Preoperative 30.7°(26.2-33.7°) 14.5°(13.3-15.4°) 5.6(3-6) Body weight
Positional 6.6°(5.2-7.9°) 7.2°*(6.3-8.2°) 1.8*(1-2) 0N
Load Bearing 8.9°*(7.3-10.4°) 8.4°*(7.5-9.2°) 2°*(1-3) 131.2N(98.9-163.5)
Postoperative 10.9°*(10.1-11.6°) 8.8°*(7.9-9.7°) 2°*(1-3) Body weight

Table 1 Measurement of angles from images taken from time of surgery to follow up and the load applied at the time of imaging. Ranges are given as 95% confidence intervals around the mean for angles and force measurements, and for sesamoid position given as actual values. *Statistical analysis suggested no significant difference was found between these values at p<0.04, and p<0.03, respectively.

The preoperative radiographs showed the mean HVA was 30.7 (26.2-33.7), IMA was 14.5 (13.3-15.4) sesamoid position was 5.6 (mode 5; range 3-6). On completion of surgical correction the positional view showed the corrected HVA was 6.6 (5.2-7.9), IMA was 7.2 (6.3-8.2) and sesamoid position was 1.8 (mode 2; range 1-2). Our simulated load bearing with an average of 131.2N (98.9-163.5N) demonstrated an increase in the HVA to 8.9 (7.3-10.4), the IMA was 8.4 (7.5-9.2) and sesamoid position was 2 (mode 2; range 1-3) (see figure 4).

  HVA IMA Sesamoid Position
6-week weight bearing view 7.5°(6.2-9.9°) 9.6°(7.2-11.9°) 2(1-3)
3-6 month weight bearing view 7.9°(5.9-10.4°) 9.3°(7.1-12.6°) 2(1-3)

Table 2 Measurement of angles from 14 patients taken from 6-week and 12-24 week weight bearing radiographs after surgery.

Postoperative radiographs showed the mean HVA increased to 10.9 (10.1-11.6), IMA was 8.8 (7.9-9.7), and median sesamoid position 2 (mode 2; range 1-3) (Table 1). We observed that the simulated weight bearing views were a closer approximation to the 6-week weight bearing view in all indices recorded (p<0.05). They showed an improvement in the HVA angle and each individual angle measured. The sesamoid position was found to follow a normal distribution (p<0.05) for each image.

Our surgical database identified 14 patients whom underwent sequential bilateral foot surgery and consequently had 3 – 6 month post-operative weight bearing images of their original correction. The results showed an observed difference in HVA and IMA but no change in sesamoid position, from the 6- week weight-bearing image (Table 2). Ranges are given as 95% confidence intervals around the mean for angles.

We found that all populations fitted a normal distribution and there was no difference between HVA (p<0.03), IMA (p<0.05), and sesamoid position (p<0.02) in the radiographic views. Our results also bear out the fact that a positional view does not give a reliable measure of the final HVA as the null hypothesis could not be rejected. The observed difference in HVA and IMA were not significant.

Discussion

In the original paper by Elliot et al in 2011 [3] non-loading intraoperative radiographs were thought to be reliable and reproducible. However, there was a statistically significant increase in post-operative weight bearing HVA compared with the measurements made intraoperatively. This is important, as hallux valgus correction requires accurate assessment of the HVA angle. Whilst in their series the mean HVA was within normal limits the actual difference between intraoperative and post-operative image was 8.9 degrees and post-operative HVA measurements ranged from 4.5-13.6. This is of significance when it is taken into account that normal HVA is less than 15-20 degrees [1].

Our results show that simulated load bearing on the forefoot whilst the ankle is held in talar-neutral will give a closer approximation to the 6 week weight bearing view in all measurable indices – particularly the HVA than simple placement as suggested by Elliot et al [5].

Our standardized load bearing images require the patient to be able to flex the knee to 60 degrees, and require the hip to flex to 60 degrees and depend on the surgeons ability hold the foot at the ankle and the radiographer’s skill to simulate weight bearing. This achieved the constant end point of the patient’s maximal ankle dorsiflexion, which is a reliable and reproducible end point allowing the surgeon to lock the foot and preventing rotation leading to a semi oblique view. Our results suggest measurement pressures are highly variable (90-180N) unlike the constant end point of maximal ankle dorsiflexion that is dependent on patient ankle mobility. Loading of the forefoot soft tissues in this manor produced an average of 131.2N once the ankle is fully dorsiflexed. This is not anyway near the forces generated on weight bearing and would account for the measurable differences in angle measurements between the different image time points.

We infer that simulated weight bearing seems to allow loading of the medial capsular repair but not with the high pressures one would expect in a weight bearing view. However, our belief is that the range of motion in the ankle may well be the limiting factor in achieving more force but it may avoid rotation of the foot and getting a semi-oblique image during surgery when trying to simulate true weight bearing. Thus, leading to a more reproducible and accurate measure of HVA.

Further studies would be required to assess where the additional force generated on weight bearing may be taken up e.g. by the elastic nature of the tissues such as the intermetatarsal ligaments and dynamic forces acting on the first metatarsal conform to Hooke’s Law to prevent excessive separation of the first and second rays.

Our experience using intraoperative fluoroscopy revealed two separate occasions where the intraoperative images led the surgeon to make an alteration in the orientation or degree of sesamoid correction performed through improved soft tissue release and medial capsular reefing (sesamoid position 5 to 3). In the second case the osteotomy required a further lateral shift to correct the HVA (14.8 to 11.6).

The mean corrections in this study for HVA were within 1-3 degrees (HVA 9.7 vs. 9.9 and IMA 8.8 vs. 6.4) of previously published results from one senior author (M.S.H.) [6]. Thus, we would recommend intra-operative fluoroscopy as a useful aid in the early stages of learning the scarf osteotomy and the many steps to refine this technique [7]. Thus avoiding common procedural problems such as under correction, mal-rotation, metatarsal fracture, and troughing as well as a better appreciation of potential interphalangeus deformity [1,2,5].

Our unit has found that adequate surgical exposure leads to a satisfactory view of the sesamoids and the osteotomy site; providing adequate assessment of correction obtained from the osteotomy and soft tissue release and would not routinely use intraoperative imaging once the surgeon was appropriately skilled in the procedure.

We are aware that some surgeons do not request postoperative radiographs routinely after scarf osteotomy but instead rely on clinical indices [1,8,9]. Even though our results support the use of a reproducible simulated load bearing intraoperative image as a close approximation of actual hallux valgus correction, we could not recommend them as a surrogate for a final united position, and they should not be used in isolation.

References

1. Coetzee JC. Scarf osteotomy for hallux valgus repair: the dark side. Foot Ankle Int. 2003;24 (1): 29-33. –[Pubmed]
2. Smith AM, Alwan T, Davies MS. Perioperative complications of the Scarf osteotomy. Foot Ankle Int. 2003;24 (3): 222-7. – [Pubmed]
3. Elliot RR, Saxby TS, Whitehouse SL. Intraoperative imaging in hallux valgus surgery. Foot Ankle Surg. 2012;18 (1): 19-21. – [Pubmed]
4. Hardy RH, Clapham JC. Observations on hallux valgus; based on a controlled series. J Bone Joint Surg Br. 1951;33-B (3): 376-91. – [Pubmed]
5. Hammel E, Abi chala ML, Wagner T. [Complications of first ray osteotomies: a consecutive series of 475 feet with first metatarsal Scarf osteotomy and first phalanx osteotomy]. Rev Chir Orthop Reparatrice Appar Mot. 2007;93 (7): 710-9. – [Pubmed]
6. Prasad S, Lake A, Hannah H, Hennessy M. Scarf osteotomy for correction of hallux valgus: clinical and radiological evaluation. J Bone Joint Surg Br 2003;85-B no. SUPP III 248. Webpage
7. Weil LS. Scarf osteotomy for correction of hallux valgus. Historical perspective, surgical technique, and results. Foot Ankle Clin. 2000;5 (3): 559-80. – [Pubmed]
8. Dafydd M, Green N, Kadambande S. Are routine x-rays 6 weeks post scarf osteotomy for hallux valgus necessary? J Bone Joint Surg Br. 2012;94-B no. SUPP XLIII 9. – [Webpage]
9. Resch S, Ryd L, Stenström A et-al. Measuring hallux valgus: a comparison of conventional radiography and clinical parameters with regard to measurement accuracy. Foot Ankle Int. 1995;16 (5): 267-70. –[Pubmed]

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