Mylène Jansen

354 Chapter 17 Methods Knee joint distraction patients 63 Patients were included for KJD treatment in 3 different trials. Of these 63 patients, 20 patients with an indication for TKA and age <60 years old were included in the OPS. Secondly, 20 TKA-indicated patients <65 years old were treated with KJD in an RCT comparing KJD with TKA. The third and last group of 23 patients with medial compartmental knee OA, an indication for HTO and age <65 years were treated with KJD in an RCT comparing KJD with HTO. In- and exclusion criteria have been described before and included radiographic signs of tibiofemoral OA (Kellgren-Lawrence grade >2, judged by orthopedic surgeon), <10º knee malalignment, BMI <35, and no presence or history of inflammatory or septic arthritis. 33,34 All trials complied with the Declaration of Helsinki, were granted ethical approval by the medical ethical review committee of the University Medical Center Utrecht (protocol numbers 04/086, 10/359/E, and 11/072) and were registered in the Netherlands Trial Register (trial numbers NL419, NL2761 and NL2680). All patients gave written informed consent. Distraction surgery was performed using an external fixation frame. The knee was distracted 2 mm during surgery and 1 mm every day during a short hospitalization until 5 mm distraction was reached, confirmed on radiographs. Patients were discharged with prophylactic anticoagulant to use during treatment and were allowed full weight-bearing of the treated knee, supported by crutches if necessary. After 6 to 8 weeks the distraction frame and pins were surgically removed. Follow-up Patients visited the hospital multiple times, including at baseline and 1 and 2 years after treatment, during which standardized weight-bearing, semi-flexed posterior-anterior radiographs were performed according to the Buckland-Wright protocol, using an aluminum step wedge as a reference standard for image analysis using ‘knee images digital analysis’ (KIDA) software (described below). 35,36 Patients completed the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC, version 3.1) questionnaire as well. Only patients with standardized radiographs at both baseline and 2 years were included. High tibial osteotomy patients HTO patients from the KJD versus HTO trial were used to study generalizability of the concept of osteophyte formation during regenerative treatments demonstrating endogenous cartilage repair activity. The 46 HTO patients were included in the trial to be treated with biplane medial-based opening-wedge osteotomy and had the same follow-up as described above for KJD patients. Only patients with standardized baseline and 2-year radiographs were included in the analyses. The HTO patients were compared to the 23 KJD patients (KJD HTO ) from the RCT comparing KJD and HTO.