Knee

Distraction in knee osteoarthritis

The treatment of patients with early onset osteoarthritis (OA) is difficult. With poor outcomes from arthroplasty (in terms of longevity and function), surgeons have reached for other options such as osteotomy, medical therapies and even joint distraction. Surgeons in Utrecht (the Netherlands) have presented a prospective series of patients treated with distraction for early onset osteoarthritis of the knee. The study team included 20 patients under the age of 60, with a VAS score of > 60 mm. Patients included in this study presented with end-stage knee OA and an indication for total knee replacement (TKR). They underwent two months of knee joint distraction (KJD) and their outcomes were assessed using serial VAS pain scores and the WOMAC questionnaire. This comprehensive study also included assessment of cartilage structure and function. KJD was applied for a mean of two months (54 to 64 days) and clinical parameters assessed using the WOMAC questionnaire and VAS pain score. Changes in cartilage structure were measured using quantitative MRI, radiography, and biochemical analyses of collagen type II turnover (ELISA). Follow-up was to just over two years on average and patients experienced a sustained clinical improvement, with improvements in WOMAC scores by 74% and VAS pain scores by 61%. Remarkably, the investigators also report increases in cartilage thickness (from 2.35 mm to 2.78 mm) and sustained decreases in the ratio of collagen breakdown to synthesis (as determined by ELIZA).² This is an interesting paper which is almost ‘too good to be true’. While not a definitive study in terms of numbers of patients, this study dangles the attractive carrot of a comprehensive assessment of the effects of distraction on both the symptoms and biology of early osteoarthritis of the knee.