A Biomechanical Comparison of Alternative Graft Preparations for All-Inside Anterior Cruciate Ligament Reconstruction
PURPOSE:To biomechanically compare alternative graft constructs for all-inside anterior cruciate ligament (ACL) reconstruction in the event that the semitendinosus harvested is too narrow or too short to make a graft larger than 8Â mm. METHODS:Bovine extensor tendons were used to make 6 different 9-mm-diameter grafts: traditional 4-strand, anastomosis 4-strand, 6-strand, 3-strand, button-fixation 4-strand, and loop-and-tack 4-strand grafts. The grafts were then subjected to cyclic biomechanical testing followed by failure loading. Force at 3 and 5Â mm of displacement and ultimate force were recorded for all grafts. RESULTS:Compared with the traditional 4-strand graft, the only graft that showed significant biomechanical differences during the cyclic phase of testing was the button-fixation 4-strand graft, which was characterized by lower force at 3Â mm of displacement (74 Â± 34Â N vs 122 Â± 13Â N, PÂ = .004) and 5Â mm of displacement (122Â Â± 35Â N vs 172 Â± 3Â N, PÂ = .006). During failure loading, ultimate force was significantly lower for both the 6-strand graft (491 Â± 186Â N, PÂ = .041) and button-fixation 4-strand graft (326 Â± 27Â N, P < .001) than for the traditional 4-strand graft (778 Â± 176Â N). All other grafts were equivalent for the parameters tested. CONCLUSIONS:The anastomosis 4-strand, 3-strand, and loop-and-tack 4-strand grafts do not biomechanically differ in cyclic loading and ultimate force from traditional 4-strand grafts. This study supports the use of anastomosis 4-strand, 3-strand, or loop-and-tack 4-strand grafts in the event that a traditional all-inside 4-strand graft cannot be prepared from a harvested semitendinosus tendon in ACL reconstruction. CLINICAL RELEVANCE:This study tests and describes alternatives to the traditional 4-strand semitendinosus autograft for all-inside ACL reconstruction in the event that the harvested tendon is not adequate.