The Benefit of Arthroscopic Partial Meniscectomy in Middle-Aged Patients - A Double-Blinded Randomized Placebo (Sham) Controlled Multi-Centre Trial

BACKGROUND Osteoarthritis (OA) is the most common form of arthritis and affects 4.5 % of the Danish population. The knee is one of the most affected joints and 45 % of all OA-related hospital contacts are related to the knee. OA has a long 'pre-clinical' phase with joint changes without symptoms. Then comes a symptomatic phase with pain and functional limitations. This is sometimes accompanied by structural changes visible on plain X-ray examination and other pathological changes like focal areas of damage to the articular cartilage, centered on load-bearing areas. After this, new bone formation at the joint margins (osteophytosis) develops along with changes in the subchondral bone, variable degrees of mild synovitis, and thickening of the joint capsule.

The meniscus plays an important role in the development of osteoarthritis. Meniscus tears can be both a risk factor for knee OA as well as a sign of disease . Both meniscus injury and a meniscectomy contribute to the development of knee OA. The surgical removal of the damaged parts of a meniscus tear puts the knee at high risk of later developing OA . Surgical resection also leads to increased joint cartilage contact stress through altered load transmission, decreased shock absorption, and decreased joint stability .

The current standard treatment for a degenerative meniscus tear is arthroscopic partial meniscectomy (APM). Arthroscopic surgery is one of the most frequent orthopaedic procedures with approximately 10,000 APM procedures being done per year in Denmark .

The benefit from an APM procedure is, however, uncertain and needs to be further investigated. As mentioned above, it significantly increases the risk of developing knee OA. The investigators also know that a significant placebo effect is present in arthroscopic knee surgery including the APM procedure . It has furthermore been shown that patients with a degenerative meniscus tear can recover without surgery and by exercise alone , . The recovery period after an APM procedure is also much longer than most surgeons realize, with disability still evident after 3 months.

The investigators need to investigate the placebo effect in younger patients with a degenerative meniscus tear but without knee OA by implementing additional well-designed, randomized, placebo controlled trials to reveal the true effects of the APM procedure on a short-and long-term basis.