Mylène Jansen

276 Chapter 14 Abstract High tibial osteotomy (HTO) and knee joint distraction (KJD) are joint-preserving treatments that unload the more affected compartment (MAC) in knee osteoarthritis. This post-hoc study compares 2-year cartilage thickness changes after treatment with KJD versus HTO and identifies factors predicting cartilage restoration. Patients indicated for HTO were randomized to KJD (KJD HTO ) or HTO treatment. Patients indicated for total knee arthroplasty received KJD (KJD TKA ). Outcomes were the MRI mean MAC cartilage thickness and percentage of denuded bone area (dABp) change 2 years after treatment, with radiographic joint space width (JSW) as reference. Cohen’s d was used for between-group effect sizes. Post-treatment, KJD HTO patients (n=18) did not show significant changes. HTO patients (n=33) displayed a decrease in MAC cartilage thickness and increase in dABp, but increase in JSW. KJD TKA (n=18) showed an increase in MAC cartilage thickness and JSW and decrease in dABp. Osteoarthritis severity was the strongest predictor of cartilage restoration. Kellgren-Lawrence grade ≥3 showed significant restoration ( p< 0.01) after KJD; grade ≤2 did not. Effect sizes between severe KJD and HTO patients were large for MAC MRI cartilage thickness ( d =1.09; p= 0.005) and dABp ( d =1.13; p= 0.003), but not radiographic JSW ( d =0.28; p= 0.521). This suggests that in knee osteoarthritis patients with high disease severity, KJD may be more efficient in restoring cartilage thickness.