Changes in Cartilage Thickness and Denuded Bone Area after Knee Joint Distraction and High Tibial Osteotomy-Post-Hoc...

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 two-year cartilage-thickness changes after treatment with KJD vs. 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 two years after treatment, using radiographic joint space width (JSW) as the 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 an increase in dABp, but an increase in JSW. KJD_TKA (n = 18) showed an increase in MAC cartilage thickness and JSW, and a 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.