Mylène Jansen

User-friendliness of a dedicated KJD device 131 7 Introduction Knee joint distraction (KJD) is a joint-preserving surgical technique for treatment of severe tibiofemoral osteoarthritis (OA) in younger patients who are indicated for total knee arthroplasty (TKA). 1 Performing a TKA in this relatively young population (<65 years) brings an increased risk of a complex and costly revision surgery later in life. 2–4 This is specifically the case for male patients, who encounter an almost doubled risk for revision compared to female patients. 2 Joint-preserving therapies, such as KJD, aim to delay TKA in this population and possibly prevent a revision surgery. 5,6 Data from multiple clinical trials showed clinical improvement and cartilage regeneration of the affected joint in patients treated with KJD. 7–11 Also, it was shown that a primary TKA could be postponed for a clinically relevant period of 5 years in over 70% of the patients up to even 9 years in around half of the patients. 12,13 The best results have been described in males (72% survival after 9 years), who also show the highest risk for revision of a primary TKA, making KJD worth considering in treatment of severe knee OA. 2,13 During KJD, the affected joint is temporarily and fully mechanically unloaded by increasing the joint space with a distraction device, which is rigidly connected with half pins to the femur and tibia. The most common fixation and distraction technique is performed bilaterally with 8 extra-articular half pins and 5 millimeters distraction for a period of 6 to 7 weeks. 14,16 In the absence of a dedicated device intended for KJD, this procedure has been performed in clinical trials with external fixation devices that are applied for various indications including stabilization of fractures and limb lengthening. 1 This broad range of applications comes with unrequired features when these devices are used for KJD, and limitations in terms of complexity of surgery, procedure time, alignment of the device and ease of use for all users including surgeons and patients. The treatment burden might be reduced when a dedicated device for KJD with optimized specifications for its intended use, e.g. the size, weight, and application method, is used. The continued use of existing external devices in daily care outside intended use, is not allowed under EU Medical Device Regulations (MDR), motivating the development of a specific device for KJD. This KJD device might also reduce the risk of misuse, ultimately leading to a safer and more efficient procedure. 17 The clinical demand for a dedicated KJD device originated from the clinical benefits that were achieved with KJD treatment in clinical trials. 10,12 In a multi-disciplinary setting with clinicians, patients, and medical device experts, a device intended for KJD was developed and made available for clinical application. Device characteristics that were defined and incorporated in the dedicated device are given in Table 1. In this study, user-friendliness is compared between the newly developed dedicated distraction (DD) device and the previously used device that served as a proof-of-concept distraction (CD) device for KJD (Figure 1); clinical efficacy and tissue structure repair are beyond the scope of this study.