Purpose

Focal full-thickness chondral defects combined with angular deformities may progress to osteoarthritis if left untreated. High tibial osteotomy (HTO) is advocated to correct the mechanical malalignment and compartmental overload. However, with this approach, the articular cartilage defect is not addressed, cartilage degeneration continues and progression of varus malalignment and/or postoperative correction loss may occur. Moreover, patellofemoral arthrosis is a relative contraindication for HTO, and inlay arthroplasty (IA) may provide a treatment solution for patients who are not perfect candidates due to patellofemoral lesions but are otherwise eligible for HTO.
The aim of this study was to compare clinical and radiological results of combined HTO and IA to those of HTO and microfracture in active, middle-aged patients with a follow-up of at least 48 months.

Methods

A retrospective analysis was undertaken for consecutive patients, who underwent medial opening wedge high tibial osteotomy (MOWHTO) combined with IA (group 1) or MOWHTO and microfracture (group 2) between 2010 and 2016. Patients with a varus malalignment =7°, no history of previous knee surgery, no ligamentous instability, intact lateral compartment, and a minimum follow-up of 48 months were included. Patients with patellofemoral instability and/or malalignment/incongruency were excluded. WOMAC, KSS, and Kujala scores, plain x-rays, and orthoroentgenograms were evaluated preoperatively, at 6 months postoperatively, and yearly thereafter.

Results

Forty-one knees as group 1 and 62 knees as group 2 were enrolled. Mean follow-up was 92.3 months. All knees in both groups were realigned to a neutral mechanical axis of 0°. The mean WOMAC and KSS scores were improved for both groups. There was no significant difference between groups regarding both scores (p=0.12). Mean Kujala score improved significantly from 55 to 79 (p<0.001) for patients with trochlear IA in group 1 and from 58 to 72 (p=0.012) for patients with patellofemoral lesions in group 2 (p=0.035). There was no loss of correction in group 1 at final follow-up, but group 2 showed a correction loss of 0.65°±1.2°.

Conclusion

HTO with inlay resurfacing arthroplasty is an effective treatment method for active middle-aged patients with medial joint narrowing and focal cartilage defects of the medial femoral condyle and/or trochlea with the additional benefit of preventing postoperative correction loss. This combination also provides a treatment solution for patients with patellofemoral chondral lesions.