ANATOMIC AND CLINICAL FACTORS AFFECTING OUTCOME OF SCARF OSTEOTOMY FOR HALLUX VALGUS

Abstract

Purpose of the study: Scarf osteotomy is currently the gold standard treatment for hallux valgus. The purpose of our work was to search for anatomic and clinical factors affecting the outcome.

Material and methods: This retrospective review concerned 125 osteotomies performed in 105 patients (101 women and 4 men, mean age 48 years, age range 16–75 years). For 55 cases, Scarf osteotomy was associated with osteotomy of the proximal phalanx. Osteotomies to reduce the lateral metatarsals were performed in 32 cases. Clinical outcome was assessed in terms of pain, hallux function and motion using the AOFAS and Groulier systems. AP and lateral weight-bearing views were used to assess the metatarsophalangeal, intermetatarsal, interphalangeal, PPAA, DMAA, and Djian angles and metatarsal slope.

Results: Mean follow-up was 45 months (range 24–95). The Kiaoka and Groulier score improved respectively from 50 to 84/100 points and 38 to 68/100 points (p< 0.0001). Pain relief was total or nearly total in 95% of patients. MPJ stiffness was related to gastrocnemius retraction, osteoarthritic degeneration, and residual deformation (p< 0.05). Subjectively, 72% of patients were satisfied or very satisfied, corresponding to 73% good or very good results. At last follow-up M1P1, M1M2 and DMAA had decreased significantly (p< 0.001) respectively improving from 33° to 18°, 14° to 9.5° and 13.2° to 9.4°. Conversely, mean P1P2 and PAA increased significantly (p< 0.05) because certain inter- and intraphalangeal deformations, radiographically masked by the preoperative hallux pronation, were not corrected. There were 29 recurrences (MP angle > 25°) statistically related to under correction of the intermetatarsal angles (p< 0.0001), M1M5, DMAA (p< 0.05), persistent hallomegaly (p=0.015), and presence of an oblique cuenometatarsal space (p=0.02). Recurrence was more frequent in patients with flat foot (p=0.04); greater calcanceal valgus was associated with wider MP angle (p=0.02).

Discussion and conclusion: Scarf osteotomy enabled complee correction of 80% of the deformations. To improve the final outcome, displacement of the first metatarsal should correct the metatarsus varus and the DMAA. Careful radioclinical analysis pre- and intra-operatively should held detect posterior (flat foot) and anterior (hallomegaly, inter- and intraphalangeal crossover) of the MPJ because they significantly influence persistence or recurrence of the deformation.