Purpose: Concomitant unloading procedures, such as high tibial osteotomy (HTO), are increasingly recognized as an important part of cartilage repair. This study presents survival rate, functional outcome, complication rate, and return to work following combined single-stage autologous chondrocyte implantation (ACI) and HTO.
Methods: Forty patients with a mean follow-up of 60 months with isolated full thickness cartilage defects of the medial femoral condyle (MFC) and concomitant varus deformity were included in this retrospective case series. All patients were treated with a single-stage combined ACI and HTO between January 2004 and December 2010. Functional outcome was evaluated prior to surgery and at follow-up using standard scores (Lysholm, VAS, KOOS). Treatment failure was defined as the need for re-operation. Return to work was evaluated using the REFA score.
Results: With all patients (mean age 36.8 SD ± 8.1 years; varus deformity 4.9 ± 1.8 °; mean defect size 4.6 ± 2.1 cm²) a clinical investigation was performed a mean of 60.5 months (SD ± 2.5) postoperatively. Four patients required reintervention (failure rate 10 %). VAS decreased significantly from 6.7 ± 1.9 points preoperatively to 2.2 ± 1.3 points postoperatively. The mean Lysholm score at follow-up was 76.2 ± 19.8 points. The mean KOOS subscales were 81.4 ± 18.0 for pain, 81.3 ± 14.0 for symptoms, 87.6 ± 16.2 for activity in daily living, 66.7 ± 22.8 for function in sport and recreation, and 55.5 ± 22.0 for knee-related quality of living. Mean duration of incapacity from work was 94.5 ± 77 days. Absenteeism from work depended on work load (return to work REFA 0: 68.9 ± 61.4 days vs. REFA 4: 155.0 ± 111.0 days).
Conclusion: Single-stage autologous chondrocyte implantation and concomitant high tibial osteotomy is a reliable and safe treatment with satisfying clinical outcome and improved functional outcome. However, we found a remarkable stay at work rate, which depended on the work load.