Early experience with lengthening osteotomy of the medial malleolus for ankle varus

Abstract

Osteoarthritis of the tibiotalar joint is a debilitating condition and often post-traumatic in nature and can contain deformity. Historically, significant coronal plane deformities were considered contraindications for total ankle arthroplasty. To preserve long term success and balance the loading of any ankle arthroplasty one must focus on correcting any aberrations in alignment of the foot, ankle, or leg. Varus deformity at the tibiotalar level is common but there is no standard treatment for its correction prior to prosthesis implantation. A retrospective review was undertaken to quantify deformity correction and viability of a medial malleolar lengthening technique with intercalary allograft. Ten patients met inclusion and exclusion criteria. Transverse opening osteotomy with bone allograft osteotomy was made just distal to the medial malleolar shoulder in a staged fashion or simultaneously with total ankle arthroplasty. A mean age of 60.3 years and mean body mass index of 26.3 (kg*m²) was observed. Seventy percent (7/10) of osteotomies progressed to union (7/10) at an average follow up of 24.7 months. All nonunions (3/3) were asymptomatic. Pre-operative average tibiotalar angle was 70.9 degrees, and post-operative was 87.9 (p < 0.001). All but 2 patients had ancillary procedures in addition to malleolar osteotomy and ankle arthroplasty. While promising, patients may need to be counseled that asymptomatic pseudoarthrosis is common (30 %). Further research is needed regarding management of coronal plane deformities of the ankle.