Mylène Jansen

90 Chapter 5 Figure 2 : Examples of postoperative radiographs, (A) left knee treated with high tibial osteotomy, (B) right knee treated with knee joint distraction. Sport and work outcome measures Our primary outcome measures were the RTS and RTW rates after HTO and KJD at 6 and 12 months. Secondary outcome measures included time to RTS and RTW, the frequency, duration and type of performed sports, experienced difficulty performing work-related knee demanding activities and physical requirements of the jobs performed. Patients were asked to retrospectively report sports participation at 4 time points (presymptomatically, 1 year preoperatively, 1 year postoperatively and at final follow-up). RTS was defined as: a patient participating in 1 or more sports preoperatively (presymptomatically or 1 year preoperatively), who resumed participation in or more sports postoperatively (1 year postoperatively or final follow-up). Also, sports ability at follow-up, compared to the patient’s best sports ability in their lifetime, was asked (“much worse”, “worse”, “unchanged”, “improved”, “much improved”). To assess the level of impact, sports activities were rated as low-, intermediate- or high-impact according to the classification by Vail et al . 31 Finally, the validated Tegner activity scale (0–10; higher is more physically active) and Lysholm score (0–100; higher is better function) were collected. 32 To assess experienced difficulty with work-related knee demanding activities, the 13-items validated WORQ questionnaire was used. 33 Patients grade the difficulty they experience when performing different activities on a 5-point Likert scale, with 4 indicating ‘no difficulty’ and 0 indicating ‘extreme difficulty/unable to perform’. Patients were asked to retrospectively grade the difficulty at 3 time points: presymptomatically, 3 months preoperatively and 1