Mylène Jansen

One-year follow-up after KJD treatment with the KneeReviver 171 9 0.86. This resulted in a required sample size of 30 patients per group. From the 4 sample size calculations, the highest required number of patients was 37 for the WOMAC and 30 for the minimum JSW. Since the number of available patients with complete datasets treated in the RCTs with the Monotubes was 39, it was decided to include the first 39 KneeReviver patients with complete datasets in this analysis. As such, the sample size was large enough for all primary analyses, and a 1:1 ratio could be used between the 2 groups. Patients Relatively young patients with end-stage knee osteoarthritis, defined by persisting, conventional treatment-resistant pain with cartilage tissue damage in general practice considered for total (or compartmental) knee arthroplasty or high tibial osteotomy (with limited axis deviation), were offered knee joint distraction by the orthopedic surgeon as alternative joint-preserving treatment. Patients in the KneeReviver study were included in 5 different hospitals: the Martini Hospital Groningen, University Medical Center Utrecht, Amphia Hospital Breda, Antwerp University Hospital, and Maastricht University Medical Center. The following criteria were applied for both the prospective KneeReviver study as well as the 2 RCTs. In order to be eligible to participate in this study, patients had to meet all inclusion criteria: adults ≤65 years of age; BMI <35 kg/m2 with max 110 kg body weight; normal-good physical condition (arbitrarily defined by orthopedic surgeons); sufficient knee joint stability (arbitrarily defined by orthopedic surgeons); sufficient range of motion (arbitrarily defined by orthopedic surgeons); radiographic signs of joint damage (Kellgren-Lawrence grade 2 – 4); Visual Analogue Scale (VAS) pain >40/100 (conservative treatment resistant). Patients that would not be considered for arthroplasty or osteotomy because of psychosocial condition were excluded, as were those meeting any of the exclusion criteria: comorbidities that would compromise the efficacy of knee joint distraction (arbitrarily defined by orthopedic surgeons); history of inflammatory or septic arthritis; knee malalignment of more than 10 degrees; previous surgical interventions of the index knee <6 months ago; absence of any radiographic joint space width on both sides (medial and lateral); presence of an endoprostheses elsewhere. The prospective KneeReviver trial and both RCTs were granted ethical approval by the medical ethical review committee of the University Medical Center Utrecht (protocol numbers 17-293, 10/359, and 11/072) and registered in the Netherlands Trial Register (trial numbers NL7986, NL2680, and NL2761). All patients in all trials gave written informed consent.