Jansen MP, et al. - Authors assessed the 9-year treatment outcome of knee joint distraction (KJD), a joint-preserving surgery for severe osteoarthritis (OA), as treatment for knee osteoarthritis and identified the characteristics predicting long-term treatment success. Long-lasting clinical and structural improvement was demonstrated by knee joint distraction (KJD). Along with a greater survival rate for males (>two out of three), they noted the importance of the initial cartilage repair activity for long-term clinical success.