[Baker's cyst--a pre-arthrotic factor?].

Between July 1989 and 1994 127 Baker-cysts have been operated and histologically examined with synovial biopsies out of the same knee. All Baker-cysts and synovial biopsies - including out of synovial membranes without macroscopically pathological findings and without other pathological intraarticular causal lesions - revealed a chronic synovitis. The Baker-cyst has to be regarded as a primary or secondary causative factor of chronic effusions and involves the development of a chronic synovitis by the disorder of the synovial and hydraulic system of the knee-joint. The exstirpation of the Baker-cyst as a prearthrotic factor is advised therefore.