['The aim of the study was to determine whether medial meniscal substitution with a polyurethane scaffold (Actifit(®)) improves the outcome of medial meniscal-deficient varus knees undergoing open-wedge high tibial osteotomy.', 'Sixty patients with symptomatic varus knees those who underwent open-wedge high tibial osteotomies were prospectively studied. In 30 patients, the medial meniscus was left with a defect larger than 25 mm (Group M). An Actifit(®) device was implanted (Group A) in the remaining 30 patients. Patients were functionally evaluated with WOMET, IKDC and VAS. Patient satisfaction was graded from 0 (not satisfied) to 4 (very satisfied).', 'Both groups were comparable preoperatively. They had similar follow-up periods (31.2 months; range 24-47.5; n.s.). WOMET improved a mean of 53.4 ± 8.4 and 42.4 ± 17.2 points in Groups M and A, respectively (p = 0.002). IKDC improved a mean of 56.7 ± 12 and 50.3 ± 15.6 points in Groups M and A, respectively (n.s.). VAS dropped 5.9 ± 2.1 and 4.7 ± 2.8 points in Groups M and A, respectively (p = 0.006). Patient satisfaction averaged 3.3 ± 0.8 and 3.3 ± 1 in Groups M and A, respectively (n.s.).'] Does partial meniscus substitution with a polyurethane scaffold improve outcome after an open-wedge high tibial osteotomy?