Failure of osteointegration of hamstring tendon autograft after anterior cruciate ligament reconstruction

Anterior cruciate ligament (ACL) reconstruction is completed after implantation, when the graft material used undergoes extensive biologic remodelling and osteointegration. Failure of the osteointegration between the graft tendon and bone decreases the graft strength and induces anterior instability. We experienced 2 cases of failed osteointegration between tendon and bone after ACL reconstruction using 4 strands of the hamstring tendon. Surprisingly, osteointegration between the bone and tendon junction was not shown by intraoperative findings. The histologic findings also presented no evidence of osteointegration or biologic remodeling of the tendon. Two cases of failure of osteointegration are reported, with a review of the literature.