Mylène Jansen

278 Chapter 14 Methods Patients Patients were included from 2 different RCTs, 1 comparing KJD with HTO, and 1 comparing KJD with TKA. In the KJD versus HTO trial, patients with medial compartmental knee OA considered for HTO according to regular clinical practice were included to be treated with either KJD (n=23; KJD HTO ) or HTO (n=46; HTO). 22 In the KJD versus TKA trial, knee OA patients considered for TKA according to regular clinical practice were included for treatment with KJD (n=20; KJD TKA ) or TKA (n=40; TKA). The TKA patients were not included in this study, because they no longer had their native knee after surgery and no structural parameters could be analyzed. 21 Inclusion and exclusion criteria for both trials have been previously published, including the following inclusion criteria: radiological joint damage (Kellgren-Lawrence grade >2 as judged by the orthopedic surgeon), age <65 years (a TKA placed <65 years brings an increased revision risk 6 ), ability to undergo MRI examination, <10° knee malalignment (is preferably treated by realignment surgery), BMI <35 (mechanical limitations of the distraction frame), and no joint prosthesis elsewhere in the body (because risk of infection in case of pin tract infection occurs). 25 As part of the inclusion process, in the KJD versus HTO trial standing whole-leg radiographs were performed to measure the preoperative leg axis, while in the KJD versus TKA trial these radiographs were performed only in around half of the patients. Both trials were granted ethical approval by the medical ethical review committee of the University Medical Center Utrecht (protocol numbers 10/359/E and 11/072), registered in the Netherlands Trial Register (trial numbers NL2761 and NL2680) and were performed in accordance with the ethical principles from the Declaration of Helsinki. All patients gave written informed consent. All actions described in this manuscript were part of the original research protocol and ethical approval as well as patient informed consent; no additional actions were performed in the included patients for these post-hoc analyses. Treatment Distraction surgery (KJD) was performed using an external fixation frame (Stryker) consisting of 2 dynamic monotubes, bridging the knee medially and laterally and fixated to the tibia and femur using 8 half-pins. 25 During surgery the knee was distracted 2 mm, extended for an additional 1 mm per day during a short hospitalization until 5 mm distraction was reached, confirmed radiographically. Subsequently, patients were discharged with prophylactic anticoagulant prescribed for use during treatment and were allowed full weight-bearing of the distracted knee, supported by crutches if needed. After 6 weeks, the frame and pins were surgically removed during day treatment.