Mylène Jansen

Summary and general discussion 399 19 significant benefit, comparable between KJD and HTO both clinically, as evaluated with questionnaires, and structurally, as measured with radiographic JSW change. TKA generally showed somewhat better clinical results than KJD, but at expense of the patients’ native knee. Also, systemic (serum/urine) biomarkers in KJD patients showed a net increase of collagen type II synthesis over breakdown in the second year after treatment. Interestingly, shortly after treatment this was the opposite, as an initial negative net collagen type II synthesis was observed. As an extension on the RCT comparing KJD and HTO, return to sport and work after the 2 treatments were described in chapter 5 . The number of patients returning to sport and work was comparable between the treatments. After 6 months, 7 in 10 patients returned to sports and 9 in 10 patients returned to work. After 1 year, these rates were 16 and 19 in 20 patients for sports and work, respectively. While patients shifted towards less high-impact sports compared to pre-treatment, sports participation levels at 5 years were comparable to those at 1 year, indicating a sustained treatment effect, especially important in these younger, active OA patients independent of treatment HTO or KJD. The positive results from the clinical trials resulted in implementation of KJD in regular care in a limited number of Dutch hospitals. Clinical data from registries of these patients were compared with clinical trial data in chapter 6 . Patient characteristics were not different between regular care and trial patients, indicating application of similar selection criteria. Treatment complications, with pin tract infections occurring most often in both groups (2 in 3 patients), did not differ between regular care and trial patients either. Questionnaires showed significant clinical improvement in pain, stiffness, and function 1 year after treatment in regular care, similar to that in clinical trials, indicating that also in regular care KJD can be a viable treatment option. Since patients thus far were being treated with a device not specifically designed for KJD, a dedicated KJD device was developed in collaboration with patients, clinicians, and engineers. The aim was to develop a more user-friendly device. Its user-friendliness was assessed and compared with the previously used concept device in chapter 7 . The intervention duration when placing the dedicated device was significantly (~20%) shorter, and pin tract infections occurred less often than with the concept device (in 2 versus 3 out of 4 patients). Patient questionnaires showed the dedicated device was more user-friendly in several categories, including pin care. With that, the dedicated device contributes to further implementation of KJD treatment. In addition to the steps already made to improve user-friendliness and patient experience of KJD treatment, chapter 8 analyzes the use of cadexomer iodine ointment during KJD treatment to potentially reduce pin tract infections. Patients treated with KJD received a wound care