Opening wedge distal femoral varus osteotomy for lateral compartment osteoarthritis in the valgus knee.

INTRODUCTION: Osteotomy aims to reduce pain and the rate of progression of arthritis by correcting deformity and offloading the affected compartment. This study reports the results of a case series of opening wedge distal femoral varus osteotomies for valgus lateral osteoarthritis of the knee. PATIENTS AND METHODS: Eighteen patients underwent osteotomy surgery (21 knees) with the aim of correcting the mechanical axis to 48-50% from medial to lateral. RESULTS: The mean follow-up for the study population was 4.5 years (range 1.6 to 9.2 years). Four patients underwent conversion to arthroplasty at a mean time of 3.3 years postosteotomy. Kaplan-Meier analysis demonstrates a cumulative survival of 79% at 5 years. In the remaining 17 osteotomies, all patients reported that outcome measures improved from baseline. However, only the IKDC and pain subdomain of KOOS showed a statistically significant and clinically relevant difference. Re-operation for non-arthroplasty related surgery was common. In part this was due to symptoms related to prominence of metalwork (10). Other reasons included non-union (1), loss of correction (2), infection (1), and persistent symptoms (2). CONCLUSION: Cumulative survival of opening wedge DFVO is comparable with that reported in closing wedge series. Clinically relevant differences in the IKDC and KOOS pain scores suggest that opening wedge DFVO is a useful option in the management of valgus gonarthrosis. However, DFVO is a technically demanding procedure and re-operation, particularly for removal of metalwork, is common.