TOTAL ANKLE REPLACEMENT IN PATIENTS WITH POST-TRAUMATIC, IDIOPATHIC AND RHEUMATOID DESTRUCTIONS (STAR)

Abstract

To evaluate whether endoprosthetic ankle replacement is an adequate treatment option. the following studies involving total ankle replacement (TAR).

From June 1997 to December 2004 a total of 68 TARs were performed in 66 patients, of whom 22 received cemented implants, 40 cement-free implants, and 4 hybrid implants. The indications for TAR included post-traumatic joint destruction in 54 patients, rheumatoid arthritis in 6 patients, and idiopathic osteoarthritis in 8 patients. Bilateral TAR was performed in two patients with rheumatoid arthritis, one of whom developed surgical site infection six months after the first implantation, thus requiring arthrodesis through external fixation; follow-up of this patient revealed no abnormality, and extension/flexion was 15-0-25°. Upon follow-up visits conducted 10 to 72 months following TAR patients were grouped according to ankle score, visual analog scale, subjective symptoms, and walking distance. The average preoperative ankle score did not exceed 70 points (17–67). Thirty-nine out of 66 patients displayed a balanced gait with only minor walk abnormality as well as ranges of movement between 30° and 55° including extension above neutral (excellent and positve outcome). Fifteen out of 66 patients complained of persisting discomfort located in the medial, lateral and anterior sides of the upper ankle joint and showed extension deficits of 5 to 15° (adequate outcome). Twelve patients had a poor outcome.

A total of 34 wound revisions were required in 25 patients, including: osteosynthetic treatment of malleolar fractures in 7 patients, wound revision in 4 patients, exostosis removal in 4 patients, and extension of the Achilles tendon in 3 patients. Three arthroscopies were performed due to persisting discomfort.

Implant loosening occurred in 13 cases and was treated as follows: tibial plateau replacement (6 cases), inlay replacement (4 cases), total implant replacement (2 cases), and arthrodesis (5 cases).

Out of 66 patients, the treatment outcome was excellent in 8 patients, positive in 31 patients, and adequate in 15 patients; in 12 patients no significant therapeutic benefit in terms of upper ankle joint function and symptoms was obtained. In view of the short observation time no long-term results are available so far. In the short and medium term TAR appears to improve the range of movement of the ankle joint in two-thirds of patients who fulfil the indications for TAR, which include a satisfactory range of movement (minimum 40°) and lateral ligament stability.