Teflon/polyurethane arthroplasty of the knee: the first 2 years preliminary clinical experience in a new concept of artificial resurfacing of full thickness cartilage lesions of the knee.

Thirty-seven full-thickness knee cartilage lesions were treated with a Teflon/polyurethane composite implant in 23 patients. The preoperative diagnoses were osteoarthritis, osteonecrosis and a traumatic osteochondral lesion. The implant was fixed to the subchondral bone with Tissucol (Immuno, Vienna), a human fibrin glue. The leg was immobilized for 6 weeks followed by 8 days of continuous passive motion in parallel with full weight-bearing. High tibial osteotomy to correct a varus or valgus deformity was performed on 16 patients approximately 6 weeks after implantation of the composite implant. Fourteen patients were arthroscoped after 1 year, which demonstrated good fixation and congruity of the implant with the adjacent cartilage. All 23 patients were available for clinical and radiographic follow-up at a minimum period of 2 years after implantation. Seventy-eight percent of the patients reported complete pain relief. Eleven patients were rated as good, 3 as fair, 4 as poor, while 4 were loosenings. All loosenings were from knees with unicompartmental bipolar implantations and required only arthroscopic removal. Moreover, 21% of the patients had reduced range of motion post-operatively. No clinical synovitis was seen. This high incidence of stiff knees may be reduced by shortening or altogether eliminating the post-operative immobilization period in conjunction with early application of CPM. We conclude that a Teflon/polyurethane composite implant has been successful as a prosthetic knee resurface implant and demonstrates good biocompatibility. However, the use of unicompartmental bipolar implants should be avoided.