[The effectiveness of pes anserinus transfer for old anteromedial knee instability (author's transl)].

Old anteromedial instability of the knee joint causes an increased external rotation of the tibia against the femur. To actively control this tendenoy to increased external rotation, Slocum and Larson advocated the pes anserinus transfer (1968). An increase of rotatory muscle function of 39% after this transfer could be demonstrated experimentally (Noyes and Sonstegard 1973). Contrary to these reports, an increase of rotatory muscle power was rather the exception than the rule in our dynamometric examinations of 49 patients after transfer of the pes anserinus for old anteromedial instability. The reasons for the lack of clinically effective increase in muscle power are discussed. The advancement of the tendon of the semimenbranaceus muscle seems more advantageous as an alternative measure.