Mylène Jansen

Two-year results of KJD compared with HTO and TKA 61 4 Introduction In patients with severe knee osteoarthritis (OA), total knee arthroplasty (TKA) is generally performed effectively to reduce pain and function impairment. However, younger patients have a higher risk of failure and future revision surgery later in life. 1 With up to 40% of TKAs performed under the age of 65, joint-preserving surgery is of major importance to postpone a first prosthesis, decreasing the risk for revision surgery. 1,2 High tibial osteotomy (HTO) is a well-established surgical treatment for patients with medial unicompartmental OA in varus malalignment and shows good long-term survival with significant improvement of patient-reported outcome measures. 3,4 Also, cartilage tissue repair activity has been suggested following HTO. 5–7 Knee joint distraction (KJD) is a more recently introduced joint-preserving surgery used for bi- compartmental tibiofemoral knee osteoarthritis or unilateral OA with limited malalignment. Long-term significant clinical benefit as well as profound cartilage tissue repair have been reported in an open prospective long-term follow-up study. 8–10 In 2 independent randomized controlled trials (RCTs), KJD has been compared with TKA and KJD has been compared with HTO. 11 At 1-year follow-up KJD was non-inferior to both other treatments with respect to patient-reported outcome measures. 12,13 Cartilage repair activity appeared more pronounced in case of KJD as compared to HTO and was present in case of KJD when compared to TKA, being obviously absent in case of TKA. 12,13 The present study presents the 2-year follow-up results of these 2 independent trials at the level of patient- reported outcomes, radiographic (joint space width), and systemic biochemical (collagen type II) marker changes. It was hypothesized that there is no clinically important difference in efficacy when comparing KJD with HTO and KJD with TKA, 2 years post treatment. The primary outcome was the total Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) score. Methods Patients Knee OA patients were included in a randomized controlled trial comparing TKA with KJD, conducted in 2 centers (Maartenskliniek Woerden and Maastricht University Medical Center) between 2011 and 2014. Patients considered for TKA were randomized (2:1) to either TKA (n=40) or to KJD (n=20; KJD TKA ) treatment in blocks of 6 at each institute, using standard randomization software. The 2:1 randomization ratio was an obligation of the medical ethics committee. The sample size was on a non-inferiority hypothesis in the primary outcome measure, the WOMAC score, for which a difference of more than 15 points (standard deviation