# Preoperative activity, postoperative flexion contractures, and degree of medial cartilage damage affects achievement of high physical activity after open wedge high tibial osteotomy

## TL;DR

This study identifies factors that influence returning to high physical activity after a specific knee surgery called open wedge high tibial osteotomy.

## Contribution

The study identifies preoperative activity levels, postoperative flexion contractures, and cartilage damage as key predictors of physical activity outcomes after surgery.

## Key findings

- Higher preoperative weight-bearing leg radiograph percentage correlates with returning to high physical activity.
- Severe cartilage damage and postoperative flexion contractures reduce the likelihood of returning to high activity.
- Preoperative KOOS (Sports/Rec) scores above 35 predict better postoperative physical activity outcomes.

## Abstract

To investigate factors that affect return to physical activities after open wedge high tibial osteotomy (OWHTO), and to determine whether an optimal correction angle exists for return to physical activities.

Patients with medial osteoarthritis of the knee who underwent OWHTO at our institution were evaluated. Radiographic evaluations were performed using bilateral weight bearing long leg radiographs. The clinical evaluation consisted of the Tegner activity scale, the Knee Injury and Osteoarthritis Outcome Score (KOOS) Sports/Rec subscore, and the presence of residual flexion contracture of 10° or more in unstable hinge fractures. In addition, the degree of cartilage damage in the medial compartment was evaluated via arthroscopic surgical findings according to the ICRS classification.

Sixty patients (70 knees; 25 males and 45 females; mean age, 55.2 [32–75] years; mean follow‐up, 8.5 [3.8–12.4] years) were included in the study. The preoperative alignment defined by mean WBLR (%) was significantly higher in the Return to High Physical Activity Group (H Group: 31.0 ± 18.6) than the Return to Low Physical Activity Group (L Group: 15.9 ± 13.9). Logistic analysis showed that low preoperative WBLR and the absence of severe cartilage damage to the medial compartment, postoperative flexion contracture, and unstable hinge fracture were factors affecting return to sport. In addition, the cutoff values using the Youden Index based on ROC analysis were preoperative Tegner activity score of 4.0 and preoperative KOOS (Sports/Rec) of 35.0.

Preoperative KOOS (Sports/Rec) was a useful index for predicting postoperative return to high physical activities. Depending on the degree of arthroscopic cartilage damage, the under‐collection of cases with severe cartilage damage should be avoided.

Level IV, retrospective case series.