Elongation of simulated whipstitch post anterior cruciate ligament reconstruction tibial fixation after cyclic loading

Whipstitch-post (WSP) tibial fixation is one of the most widely used and clinically successful methods of soft tissue graft fixation for anterior cruciate ligament reconstruction (ACLR). However, some consider the method prone to laxity. We hypothesized that WSP would have low elongation rates after experimental cyclic loading. Eight cadaveric human semitendinosus and gracilis (ST/Gr) tendons had whipstitches woven into their overlapped ends. The grafts were looped around a metal bar, pneumatically clamped, and cyclically loaded. The adjusted mean experimental graft elongation for the WSP was 1.13 mm with a maximum elongation of 1.64 mm and a standard deviation of 0.32. These values are equivalent to the lowest published cyclic loading tibial fixation elongation data. Whipstitch-post tibial ACLR fixation is biomechanically sound with among the lowest rates of elongation after laboratory cyclic loading.