Objective 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 noninferiority studies. Design 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. At 2 years, the total WOMAC score (KJDTKA: +38.9 [95%CI 28.8-48.9] points; TKA: +42.1 [34.5-49.7]; KJDHTO: +26.8 [17.1-36.6]; HTO: +34.4 [28.0-40.7]; all: P < 0.05) and radiographic minimum JSW (KJDTKA: +0.9 [0.2-1.6] mm; KJDHTO: +0.9 [0.5-1.4]; HTO: +0.6 [0.3-0.9]; all: P < 0.05) were still increased for all groups. 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. Conclusions Sustained improvement of clinical benefit and (hyaline) cartilage thickness increase after KJD is demonstrated. KJD was clinically noninferior to HTO and TKA in the primary outcome.