Mylène Jansen

240 Chapter 12 for 2D measurements. By including CT in the comparison with radiographic JSW and MRI cartilage thickness, the impact of weight-bearing versus non-weight-bearing and of measuring bone-to-bone JSW versus cartilage thickness measurements can be elucidated. Methods Patients Patients treated with a joint-preserving surgical technique demonstrating cartilaginous tissue repair, knee joint distraction 21,22 , who had radiographs (x-rays), MRI scans, and CT scans before and 2 years after treatment were included for this study. Knee joint distraction has previously been reported to result in cartilaginous tissue repair by radiographic and MRI evaluation, making it a population explicitly suitable for the present evaluation. 23 Patients were included from 2 independent randomized controlled trials (RCTs). 24,25 In both trials, a subgroup of patients (both n=10) was asked to participate in an extended imaging protocol that included additional MRI and CT scans, in addition to the radiographs all patients received in these trials. Only patients who had complete imaging datasets at baseline and 2-year follow-up were included in the current study. 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) and registered in the Netherlands Trial Register (trial numbers NL2761 and NL2680). All patients gave written informed consent. Knee joint distraction is a surgical treatment for end stage knee OA below 65 years of age to postpone the need for a knee prosthesis. 26 In- and exclusion criteria of the RCTs and treatment details have been described previously. 27,28 Before treatment, the most affected knee joint compartment (MAC) medial or lateral was determined for all patients. Imaging and measurement methods An overview of the different imaging techniques and key differences between them is shown in Figure 1.