Flipped patellar tendon autograft anterior cruciate ligament reconstruction

Abstract

To determine the efficacy of an anterior cruciate ligament (ACL) graft that customizes length and facilitates anatomic outlet fixation, a prospective study of the "flipped" patellar tendon autograft ACL reconstruction began in 1995. This technique shortens the tendon portion to match the intra-articular length by rotating 1 bone plug 180 degrees proximally onto the tendon, thus flipping the bone plug over its ligamentous insertion. Bioscrews (poly L-lactic acid; Linvatec, Largo, FL) secured the grafts. All patients undergoing this procedure with a minimum 21 months follow-up were reviewed. Preoperative and postoperative Tegner, Lysholm, and IKDC activity scores, and Lachman and pivot shift tests were obtained. Postoperative KT testing and radiographs were obtained. Fifty patients were followed-up for an average of 28 months (range, 21 to 39 months). Average patient age was 34 years (range, 16 to 52 years). Tegner scores increased from 2.0 preoperatively to 6.0 postoperatively. Lysholm scores increased from 46 preoperatively to 93 at follow-up, with 86% excellent (66%) or good (20%). IKDC activity scores increased from 3.1 preoperatively to 1.7 postoperatively. KT manual-maximum difference at follow-up averaged 0.7 mm, with 74% less than 3-mm, 18% 3- to 5-mm, and 8% greater than 5-mm difference. Postoperative Lachman results were 0 in 45 patients and 1+ in 5 patients. Postoperative pivot shift was absent in all but 1 patient. Full extension was achieved in all cases and flexion averaged 136 degrees with no patient having less than 120 degrees flexion. No lytic bone changes or tunnel widening were seen. The flipped patellar tendon autograft reduces graft length to its intra-articular portion, increasing graft stability, isometry, and stiffness, and avoiding tunnel graft mismatch with clinically excellent results.