Mylène Jansen

304 Chapter 15 Methods Patients Patients were included from 2 randomized controlled trials (RCTs). In 1 RCT, patients below the age of 65 years with indication total knee arthroplasty (TKA) were randomized to KJD (n=20) or TKA (n=40) treatment. In a separate RCT, patients with medial compartmental knee OA who in regular care were considered for HTO for medial compartmental knee OA were randomized to KJD (n=23) or HTO (n=46) treatment. Inclusion and exclusion criteria for both trials were primarily based on the indication TKA or HTO have been described previously; they included age <65 years old, Kellgren-Lawrence grade (KLG) >2 (judged by orthopedic surgeon), no history of inflammatory disease, no surgical treatment of the involved knee <6 months ago, and no primary patellofemoral OA. 17,25 After inclusion in 1 of the 2 RCTs, patients randomized to treatment with KJD or HTO were asked to participate in an extended imaging protocol, extending the standard MRI scans performed in all patients with additional modalities, including T2-mapping. The first 20 HTO patients and the first 20 KJD patients (irrespective of the trial from which they originated) who gave written informed consent for the extended imaging protocol were included. From the KJD versus TKA trial, 10 KJD patients were included (KJD TKA ); from the KJD versus HTO trial 10 KJD patients (KJD HTO ) and 20 HTO patients were included. It was previously shown that patient demographics of these subgroups of KJD and HTO patients participating in the extended imaging protocol did not significantly differ from the original KJD and HTO groups, except for the proportion of male patients that was significantly higher in the whole HTO group, which was considered coincidental. 24 The original RCTs and the extended imaging protocol were granted ethical approval by the medical ethical review committee of the University Medical Center Utrecht (protocol numbers 10/359/E, 11/072 and 11/482/E). All patients gave written informed consent. Treatment The KJD treatment protocol has been extensively described previously. 15,25 In short, at surgery an external fixation device consisting of 2 dynamic monotubes was fixed medially and laterally of the knee joint, using bone pins. Over 3 days, the joint was gradually distracted to a total of 5 mm, confirmed radiographically, after which patients were discharged and allowed full weight- bearing, supported by crutches if needed. After 6 weeks of distraction, the frame was removed at day treatment, without further imposed rehabilitation protocol. For HTO treatment, biplane medial-based opening-wedge osteotomy was performed. Patients were discharged after 3 days, followed by 6 weeks of limited weight-bearing. At 18 months, the plate was removed to allow imaging at 2 years.