Mylène Jansen

60 Chapter 4 Abstract Background: Both, knee joint distraction (KJD) and high tibial osteotomy (HTO) are joint- preserving surgeries that postpone total knee arthroplasty (TKA) in younger osteoarthritis (OA) patients. Here we evaluate the 2-year follow-up of KJD versus TKA and KJD versus HTO in 2 non-inferiority studies. Methods: Knee OA patients indicated for TKA were randomized to KJD (n=20; KJD TKA ) or TKA (n=40). Medial compartmental knee OA patients considered for HTO were randomized to KJD (n=23; KJD HTO ) or HTO (n=46). Patient-reported outcome measures were assessed over 2 years of follow-up. The radiographic joint space width (JSW) was measured yearly. In the KJD groups, serum-PIIANP and urinary-CTXII levels were measured as collagen type II synthesis and breakdown markers. It was hypothesized that there was no clinically important difference in the primary outcome, the total WOMAC, when comparing KJD with HTO and with TKA. Results: Both trials were completed, with 114 patients (19 KJD TKA ; 34 TKA; 20 KJD HTO ; 41 HTO) available for 2-year analyses. The total WOMAC score and radiographic minimum JSW at 2 years were still increased for all groups (KJD TKA 38.9 points (95%CI 28.8–48.9); TKA 42.1 (34.5–49.7); KJD HTO 26.8 (17.1–36.6); HTO 34.4 (28.0–40.7); all p< 0.05) and (KJD TKA 0.9 mm (0.2–1.6); KJD HTO 0.9 (0.5–1.4); HTO 0.6 (0.3–0.9); all p< 0.05). The net collagen type II synthesis 2 years after KJD was increased ( p< 0.05). Half of KJD patients experienced pin tract infections, successfully treated with oral antibiotics. Conclusion: Sustained improvement of clinical benefit and (hyaline) cartilage thickness increase after KJD is demonstrated. KJD was clinically non-inferior to HTO and TKA in the primary outcome.