Intra-articular hyaluronic acid after knee arthroscopy: a two-year study.

Arthroscopic knee joint lavage is used when conservative treatment of knee osteoarthritis is unsatisfactory and a joint prosthesis is not yet indicated. The potentially negative effect of irrigation fluids on cartilage metabolism and structure has led to the development of a temporary synovial fluid substitute containing hyaluronic acid. The short and long-term effects of this synovial fluid substitute were investigated in a total of 80 patients with persistent knee pain. Forty patients underwent arthroscopic knee joint lavage, in some cases combined with careful cartilage debridement (group A) while a further 40 patients underwent the same procedure which, after final joint lavage, was immediately followed by a single instillation of 10 ml of the synovial fluid substitute (0.5% sodium hyaluronate) into the joint (A + HA group). After the procedure, pain on walking and restricted ability to walk 100 m were markedly reduced to a comparable extent in both groups. Three months later, the effect of the treatment assessed using various parameters (CGI, restricted ability to walk 100 m, pain on walking, night pain) had decreased in group A, while it remained stable or even improved slightly in the A + HA group. The Mann-Whitney statistics revealed a descriptive superiority for the A + HA group at this time point. One year after treatment the superiority of the A + HA group was confirmed using the same assessment parameters. No side effects or adverse events were observed for either treatment procedure. This study shows that arthroscopic knee joint lavage leads to a lasting improvement in pain and functional impairment. The post-arthroscopic instillation of a HA-based synovial fluid substitute into the joint is a suitable way of achieving long-term stabilisation of the treatment outcome. This was supported by findings of a survey of 66 patients at 2 years after treatment in this study. Level I prospective, randomised controlled double-blind study.