Knee joint distraction results in MRI cartilage thickness increase up to ten years after treatment.

Objectives Knee joint distraction (KJD) has shown long-term clinical improvement and short-term cartilage restoration in young osteoarthritis (OA) patients. The current objective was to evaluate MRI cartilage thickness up to ten years after KJD treatment, using a three-dimensional surface-based approach. Methods Twenty end-stage knee OA patients were treated with KJD. 1.5 T MRI scans were performed before and at one, two, five, seven, and ten years after treatment. Tibia and femur cartilage segmentation and registration to a canonical surface were performed semi-automatically. Statistical parametric mapping (SPM) with linear mixed models was used to analyse whole-joint changes. The influence of baseline patient characteristics was analysed with SPM using linear regression. Relevant weight-bearing parts of the femur were selected to obtain the average cartilage thickness in the femur and tibia of the most (MAC) and least affected compartment (LAC). These compartmental changes over time were analysed using repeated measures ANOVA; missing data was imputed. In all cases, p Results One- and two-years post-treatment, cartilage in the MAC weight-bearing region was significantly thicker than pre-treatment, gradually thinning after five years, but still increased at ten years post-treatment. Long-term results showed areas in the LAC were significantly thicker than pre-treatment. Male sex and more severe OA at baseline somewhat predicted short-term benefit (p> 0.05). Compartmental analyses showed significant short- and long-term thickness increase in the tibia and femur MAC (all p Conclusions KJD results in significant short- and long-term cartilage regeneration, up to ten years post-treatment.