Development of a New Activity Score for the Evaluation of Ankle Instability

BACKGROUND: Tegner and Lysholm described their generally acknowledged activity score in 1985. It was originally tested for knee ligament injuries, but for the past 17 years it has been used for other joint evaluations as well. The development of already existing and new kinds of sports, differences between knee and ankle loading, and different injury rates provided reasons for developing an ankle-specific activity score. HYPOTHESIS: The new score should have a higher reliability, validity, and sensitivity than the Tegner score when evaluating ankle-related activity changes. STUDY DESIGN: Methodological study. METHODS: Fifty-three sports, 3 working activities, and 4 general activities were inserted into a 0-to-10 category system based on the rankings of a 7 x 2-point pre-evaluation system, followed by a direct comparison with the Tegner score and reliability, validity, and sensitivity testing on 2 different patient populations. RESULTS: In direct comparison, there is a strong overall correlation of the 2 activity-scoring systems (r = 0.7565), but the ankle activity score proved to be different from the Tegner score in the higher categories, especially in the top 4 ankle score categories (r = 0.1450). Further tests demonstrated the high reliability (1.00) of the new score. Analysis of variance proved that activity changes measured by the ankle score correspond well to the difference between the patients' subjective results and their Karlsson functional scores (P =.0119). This is not the case when we measure ankle activity changes using the knee-specific Tegner score (P =.0987). Furthermore, ankle score differences spread over a wider range (-1.18 +/- 2.12) than did Tegner score differences (-0.68 +/- 1.29), which demonstrates the higher sensitivity of the new score. CONCLUSIONS: Based on these results, the new ankle activity score could be a better complement in the complex evaluation of ankle instability.