Synovial membrane changes after experimental transection of the cranial cruciate ligament in dogs

Degenerative joint disease and inflammation of the synovial membrane were produced in the left stifle of 16 dogs by severing the cranial cruciate ligament. Arthrotomy only was performed on the right stifle. Synovial membrane from these joints was histologically examined at 1, 2, 8, and 13 weeks after surgical operation. Similar tissue was obtained from 4 healthy dogs for comparison. Inflammatory changes in the synovium of the left stifle progressed with time and were prominent at 8 weeks postoperatively; subsynovial fibrosis was greatest at 13 weeks. Inflammation of the synovial membrane and subsynovial tissue was characterized by synovial cell hypertrophy and hyperplasia, plasma cell and lymphocyte infiltration, and increased vascularization of the subsynovial region.