Early results after four years experience with the S.T.A.R. uncemented total ankle prosthesis

Abstract

The first ankle prostheses appeared in 1973 as an alternative to ankle arthrodesis, which was until then the only valid solution for a painful degenerative, rheumatoid or posttraumatic ankle. Several designs followed, all with disappointing results. Low-constraint prostheses are now being used, with literature studies of 5 years follow-up. In this study, the authors have evaluated the results of 26 uncemented, hydroxyapatite-coated STAR prostheses, all implanted between January 1996 and December 1999, with an average follow-up of 15.8 months (range: 1.5 to 48 months). For evaluation, all patients filled out a questionnaire at three different moments in time, and all of them were clinically reviewed by one single observer. The Kofoed ankle score was used for clinical evaluation. All ankle prostheses were also radiographically reviewed, using a radiographic scoring system developed by the authors. Evaluation with the Kofoed ankle score showed 74% favourable results. When patients were asked to rate their satisfaction on a scale between 0 and 100, an average improvement of 50/100 was reached. Pain was the most important indication to surgery and is the only parameter that can be predictably influenced. The effects on motion and walking distance are less predictable. No major complications occurred and there were no revision operations. Should prosthetic failure occur, an arthrodesis can still be performed, as bone resection in the primary procedure has been minimal.