Joint distraction in the treatment of knee osteoarthritis: efficacy and underlying mechanisms.

Introduction:

Joint distraction is a relatively new approach in the treatment of severe osteoarthritis (OA). Clinical efficacy has been proven for hip and ankle OA.



Methods:

Patients with severe posttraumatic OA of the tibio-femoral joint, who were considered for an endoprosthesis were treated with joint distraction. Two external fixation tubes, bridging the knee joint, were placed on pins that were drilled through soft tissue and bone. Joint distraction was performed gradually until 5mm was reached (radiographically controlled). To avoid contractures of the knee joint, each two weeks the distraction tubes were removed from the pins to exercise the joint without loading. After exercising, the distraction of the joint was replaced and controlled radiographically. Absence of mechanical load on the cartilage, preventing further wear and tear, was controlled on standardized radiographs. Pain, functional disability, clinical condition, and flexion of the joint were evaluated using a box-scale, a questionnaire (slightly modified WOMAC) and by physical examination.

A two month distraction period results in similar clinical beneficial effects as a three month distraction period.

N/A

Joint distraction applies temporary (2 months) relief of mechanical wear and tear of the articular cartilage surfaces forming a joint. Nutrition of the cartilage is maintained due to intra-articular fluid pressure changes during treatment. Additionally subchondral sclerosis is diminished, diminishing mechanical stresses on the cartilage after treatment.