A non-randomized controlled clinical trial on autologous chondrocyte implantation (ACI) in cartilage defects of the medial femoral condyle with or without high tibial osteotomy in patients with varus deformity of less than 5°.

Purpose: High tibial osteotomy (HTO) is a recommended concomitant surgery when treating cartilage lesions of the medial femoral condyle (MFC). Varus deformities of 5° and more were considered an indication for HTO in patients with cartilage defects. This study compares clinical outcome in patients with ACI and concomitant varus deformity of <5° with or without additional HTO.

Methods: 43 patients with isolated cartilage defect of the MFC and varus deformity between 1° and 5° (mean age 39.14 ± 8.35 years; mean varus deformity 2.84 ± 1.19°) were included (follow-up 71.88 ± 23.99 months). Group A (n = 19) was treated with ACI and additional HTO; group B (n = 24) received ACI only. Survival rate in terms of absence of the need of reintervention was defined as main outcome parameter. In the subgroup without reintervention, functional outcome (KOOS and WOMAC) was evaluated.

Results: Overall rate of reintervention was 12 (27.9 %). Survival was significantly higher in group A (group A 89.5 %, group B 58.33 %; p = 0.023). Although a trend for better clinical outcome was observed for group A in the subgroup without reintervention, this observation lacked statistical significance (KOOS(symptoms) group A 73.23, group B 59.64; p = 0.274).

Conclusion: While there is general consensus for treating varus deformities of >5° in patients with cartilage lesions of the medial femoral condyle, HTO also leads to a reduced rate of reinterventions and longer survival rates in patients with varus deformities of <5°.