Mylène Jansen

400 Chapter 19 protocol, which for part of the patients included cadexomer iodine ointment. Patients who did not use this ointment experienced twice as many pin tract infections and 5 times as many serious infections (requiring more antibiotics than a single oral course). Using cadexomer iodine ointment during KJD treatment significantly reduced pin tract related complaints, decreasing treatment burden and further improving patient-friendliness, and should be considered as part of the standard treatment protocol. A new multicenter prospective study was started to evaluate clinical outcomes after KJD treatment with the dedicated device, and chapter 9 showed an interim analysis of 1-year follow-up results from this trial. Patient-reported clinical outcomes and radiographic JSW improved significantly after treatment and were comparable and largely non-inferior to results obtained with the previous concept device. Patient selection seemed to have shifted somewhat, as patients treated with the dedicated device had more complaints but less joint damage than patients from previous studies. Still, also with the dedicated device, KJD treatment results in significant clinical efficacy. Part II: Joint processes and working mechanisms Clinical studies initially focus on improving clinical outcome and increasing radiographic JSW (as this usually indicates cartilage restoration) but over the past years more research has been performed on the joint processes andmechanisms behind KJD. In chapter 10 , an overall picture of KJD is given, providing an overview of the current clinical evidence underscoring part I of this thesis as well as discussing different concepts of potential underlying processes introducing part II of this thesis. Supported by recent literature, it is theorized that a combination of partial unloading, joint synovial fluid (SF) pressure oscillation, subchondral mechanical and biochemical bone changes, joint-derived stem cells, and a changed molecular joint milieu is causative to the observed tissue regeneration that occurs in KJD treatment. When evaluating structural changes or processes inside the joint during or after treatment, imaging techniques are often used, as they allow non-invasive monitoring of tissue changes. Radiographically, characteristics such as JSW, osteophyte size and subchondral bone density can be assessed, using a standardized analysis method such as knee image digital analyses (KIDA). In chapter 11 , the performance of this method was evaluated in patients with severe knee OA. Intra-observer parameters were good, especially when radiographs were reevaluated within 1 month (instead of years), and for most parameters the smallest detectable difference was comparable to that observed when analyzing radiographs of patients with mild OA. As such, the analysis method was proven useful for radiographic evaluation of severe OA as well. Importantly, radiographs should be analyzed in a limited time frame and ideally in randomized order.