[The semitendinosus tendon as replacement for the anterior cruciate ligament]

This article describes the history, advantages, biomechanical properties, operative technique, and results of replacement of the anterior cruciate ligament using the semitendinosus tendon. After arthroscopic ACL replacement using the doubled semitendinosus tendon in combination with an extraarticular lateral repair in 65 consecutive patients (20 acute, 45 chronic instabilities) we found after 2 years in 51 patients (78%) an excellent or good result with less than 3 mm difference in the Lachman test measured with the KT-1000 arthrometer (MMD). After 6 years 40 out of the 45 patients with chronic instabilities could be examined again. Only 28 patients (70%) showed a difference in anterior translation of less than 3 mm. A positive pivot shift sign could be seen in 11% of the patients after 2 years and in 20% after 6 years. The Tegner score increased from 6.0 after 2 years to 6.2 after 6 years, the Lysholm score decreased from 93 to 91 in the same interval. 89% of the patients had a free range of knee motion after 2 years and 92.5% after 6 years. There were 10% normal, 50% nearly normal, 25% abnormal, and 15% severely abnormal knees in the IKDC evaluation after 6 years. In the last 4 years we are using the quadrupled semitendinosus tendon in an arthroscopic single incision technique for ACL replacement with femoral Endobutton fixation, because the doubled semitendinosus tendon seems to elongate over time. After 23 months on average (12-36 months) the preoperative anterior translation of 7.5 mm could be decreased to 1.9 mm in 35 patients.