Time to Rethink Rehab Protocol after Anatomic ACL Reconstruction?
The rate of graft failure following anatomic ACL reconstruction has been reported to be as high as 13%, nearly double the reported failure rate of transtibial reconstructions. The majority of anatomic graft failures occur six to nine months after surgery, when patients commonly return to full sports activity. Findings from a cadaver study by Araujo et al. in the November 4, 2015 edition of The Journal of Bone & Joint Surgery may help explain these phenomena.
The authors used a robotic system to measure in situ forces on 12 native cadaver ACLs and on three different reconstructions, one representing the anatomic approach and two reconstructions approximating traditional transtibial approaches. They measured forces on the grafts during anterior tibial loading and simulated pivot-shift loading.
Araujo et al. hypothesized that an anatomically positioned graft would experience increased in situ forces relative to transtibial positioning, and that is what the study revealed during knee flexion angles of 0°, 15°, and 30°. At 45°, 60°, and 90° of flexion, the transtibially positioned grafts experienced higher in situ loading forces than the anatomic ones.
While this cadaveric study is not the definitive word on this matter, with the high graft forces on the anatomic reconstructions, the authors suggest that “rehabilitation and return to sports progression may need to be modified to protect an anatomically placed graft after ACL reconstruction.”