This study demonstrated acceptable psychometric performances for the Lysholm-G and the Tegner-G scales as outcome measures for patients with TKA. A short version of the Lysholm score without the "locking" and "instability" items might be more appropriate for TKA patients.

The psychometric properties of the Tegner-G are comparable to those of the English original version. The Tegner-G is thus valid and reliable for the German-speaking part of Switzerland. The application in other German-speaking countries probably requires adaptations for some of the sports included. The relation between activity and function changes depending on time since operation. This confirms that a comprehensive assessment of the outcome after an anterior cruciate ligament injury requires the separate assessment of both parameters.