Mylène Jansen

One-year follow-up after KJD treatment with the KneeReviver 169 9 Introduction Knee joint distraction (KJD) is a relatively novel joint-preserving surgical technique indicated for end-stage osteoarthritis by which the 2 bony ends of the knee joint are placed at around 5 mm distance for at least 6 weeks using an external distraction device. 1 This treatment, as an alternative for placement of a total knee arthroplasty (TKA) at a young age (<65 years), has been evaluated in several small studies: a retrospective study 2 , a controlled trial 3 , a long-term follow-up cohort study 4–7 , and in 2 randomized controlled trials (RCTs) against TKA and high tibial osteotomy (HTO) 8–10 . In the retrospective study and controlled trial, customized frames or Ilizarov circular frames were used (Figure 1). In the cohort study and RCTs, Dynamic Monotubes (Stryker; Figure 1) were used. All studies demonstrated clear and prolonged clinical benefit and joint tissue repair. 2,3,7,10 Most importantly, the treatment was demonstrated to postpone the initially indicated TKA for over 5 years in 3 quarter of patients up to even 9 years in half of the patients. 6,7 With that, this joint-preserving treatment, delaying a first prosthesis, is considered to prevent the need for costly and less effective prosthesis revision surgery. 11 Recently, a new, dedicated KJDdevice was developed by the UMCUtrecht to facilitate surgeons and patients, the KneeReviver (ArthroSave; Figure 1). This device has comparable mechanical properties and makes use of the same pin fixation positions as the Dynamic Monotubes, but has specifications optimized for its intended use, such as a reduced size and weight, and easy pin placement and fixation. 12,13 To evaluate this device, a prospective, multicenter clinical trial with 5 years of follow-up was started. Inclusion and treatment of 65 patients was completed at the end of 2019. The treatment protocol in this prospective study was identical to that used in the RCTs performed with the Dynamic Monotubes. In both these studies, KJD patients showed clinical improvement and cartilaginous tissue repair (increased radiographic joint space width; JSW) at 1 year of follow-up. 8,9 Figure 1 : Different frames used for knee joint distraction. From left to right: custom articulated distraction device (Deie et al. 2007) 2 ; Ilizarov circular frame (Aly et al. 2011) 3 ; Dynamic Monotubes (Van der Woude et al. 2017) 6 ; KneeReviver (Jansen et al. 2020) 12,14 .