Supramalleolar osteotomy: techniques, indications and outcomes in a series of 83 cases

Introduction: Supramalleolar osteotomy is an alternative surgical procedure for the management of asymmetric early arthritis of the ankle. The main goal of this retrospective study was to evaluate the clinical and radiological benefits of supramalleolar osteotomy. The secondary goal was to identify prognostic factors to help decide upon this therapeutic indication.

Materials and methods: Eighty-three patients, mean age 45 years old (17-79), presenting with post-traumatic asymmetric early arthritis of the ankle were followed up for a mean 3.5 years (1-14 years). Sixty-two patients presented with a varus deformity (mean: 13°), and 21 with a valgus deformity (mean: 17.5°). The presence of a preoperative clinical 'sidewalk sign' was looked for and it was considered positive if pain improved when the patient walked on a surface slope that was tilted in the opposite direction of their deformity. A functional preoperative evaluation and at the final follow-up were performed using the American Orthopedic Foot and Ankle Society (AOFAS) ankle-hind foot scale. The frontal deformity was measured by the Meary angle on a weight-bearing X-ray. Varus deformities were treated by a lateral closing wedge supramalleolar osteotomy or a medial opening wedge supramalleolar osteotomy. Valgus deformities were treated by a lateral opening wedge or a medial closing wedge supramalleolar osteotomy.

Results: At last follow-up, the mechanical axis in the varus group was 1.3° and 7.5° in the valgus group. The AOFAS score significantly improved (P<0.001) by 15 points in patients with a varus deformity and 13 points in patients with a valgus deformity. A positive sidewalk sign (disappearance of pain) was correlated with a good outcome and had a positive predictive value of 0.88 (CI: 0.77-0.95) (P<0.001).

Discussion: The supramalleolar osteotomy is a conservative therapeutic surgical option for the management of arthritis of the ankle associated with varus or valgus deformities. The results are satisfactory for indications of arthritis with varus and valgus deformities and a positive 'sidewalk' sign (pain relief on a slope surface tilted in the opposite direction of the deformity).

Level of evidence: Level IV: retrospective case series.