Effects of synovial fluid on fibroblasts in tissue culture.

The ability of the torn anterior cruciate ligament of the knee to heal is unpredictable, despite early surgical repair. A popular explanation has been that synovial fluid inhibits ligament healing. Other variables of ligament healing could reside with the fibroblasts, themselves, from different ligaments. With the use of tissue culture techniques, populations of fibroblasts were cultured from human anterior cruciate ligaments, deep and superficial medial collateral ligaments of the knee. Growth of fibroblasts from the anterior cruciate ligament was always diminished when exposed to synovial fluid and, on the average, plating efficiency was reduced by 46% when the culture medium contained synovial fluid. Growth rates demonstrated that fibroblasts from the superficial medial collateral ligament grew an average of 35% more than the others. Information gained from this study provides some data to explain the clinical frustration of the torn anterior cruciate ligament. The combination of synovial fluid inhibition of cell proliferation and the variable growth rates of fibroblasts, may explain the unsatisfactory healing of cruciate ligaments.