Energy absorbed by longitudinally splitting a tibialis anterior allograft: Implications for double-bundle anterior cruciate ligament reconstruction

Purpose: Split tibialis anterior (TA) allografts have been proposed as a source for double-bundle anterior cruciate ligament reconstruction. We sought to determine whether longitudinally splitting a TA tendon leads to a change in the mechanical properties of the tendon. Methods: Seven cadaveric matched pairs of TA tendons were procured. One member of each pair was longitudinally pierced in its midportion and then bluntly split, creating 2 longitudinally divided grafts. The other member of the pair remained intact. Each tendon was then frozen into thermoelectrically cooled clamps and loaded to failure on an MTS machine (MTS Systems, Eden Prairie, MN) at a displacement of 1 mm/s. The area under the force-versus-displacement curve was calculated as an indicator of energy absorbed by the tendon before failure. The energy absorbed by the intact tendon was then compared with the summed energy absorbed by the 2 specimens obtained by splitting the sibling specimen. Results: Energy absorbed by the intact tendon was 10,300 ± 3,433 Nmm, whereas total energy absorbed by the 2 longitudinally split tendons was 10,530 ± 2,095 Nmm (P = .78). Conclusions: Longitudinal splitting of a TA allograft by the technique described does not significantly affect the graft's ability to absorb energy. Clinical Relevance: The splitting technique described can safely be used to create 2 grafts if surgeons wish to use a TA graft for a double-bundle anterior cruciate ligament reconstruction or for reconstruction by use of fixation devices requiring 2 looped tendon grafts.