New surgical technique for treatment of extraarticular knee ankylosis

Laboratory and clinical studies were conducted to evaluate a treatment regimen for extraarticular ankylosis of the knee. The study evaluated the use of a porcine biomembrane to prevent quadriceps adhesions. A canine model was studied to determine the cellular response to the membrane by evaluating biopsies at 3, 7, 14, and 21 days after surgery using light and scanning electron microscopy. The results showed that there was nonspecific inflammatory cell infiltration into the base (rough) layer of the biomembrane during the first few days, although fibroblasts were the dominant cellular response 7 days later. No significant tissue ingrowth was seen on the smooth (muscular interface) surface of the membrane. The clinical study applied the information gained from the canine model to a series of 23 patients who suffered from extraarticular knee ankylosis and who were treated with a surgical procedure in which the released interface between the femur and the muscle groups was protected with a piece of porcine biomembrane. Subjects were observed from 16 to 30 months (mean, 26 months) after surgery. An average increase in knee range of motion of 86 degrees was documented, and a 100% patient satisfaction rate was noted. The technique yields satisfactory results in terms of cost, range of motion, and postoperative pain.