Screw arthrodesis of the ankle joint. Technique and results

In ankle arthrodeses several clinical and biomechanical studies have shown the superiority of the screw technique over external fixation. As a maximum of stability is a major goal, especially for functional after-treatment or in patients with poor bone stock, the arthrodeses technique at Hannover Medical School is performed with four screws. Two parallel anterior/posterior screws are placed from the tibia to the talus, providing anterior stabilization. One screw posterio-medial has a posterior tension-wiring effect and one screw placed through the fibula to the talus acts against rotational and sagittal translation. From May 1975 to May 1995, 225 ankle arthrodeses with internal or external fixation technique were performed. Complications were found in 47% in the external fixation treatment group (n = 44) and in 10% the patients stabilized with the screw technique (n = 181). Fifty of these 225 patients had a follow-up evaluation after an average of 7.4 years (external fixation, n = 22; screw fixation, n = 28). All patients were examined and scored with three different scoring systems: (1) MHH Score, (2) Clinical Rating System according to Kitaoka et al. (1994) and (3) Outcome Questionnaire for evaluating the overall outcome. The results from the questionnaire were compared to the clinical scores. Retrospective analysis revealed a higher rate of complications for arthrodeses performed by external fixation. The overall results of all three different scoring systems showed a trend in favor of the screw-fixation technique without reaching statistical significance (P > 0.05). The results of the Outcome Questionnaire are statistically as valid as the two clinical scoring systems.