Arthroscopic biological internal bracing with remnant repair for subacute ACL femoral avulsions.

Abstract

Arthroscopic anterior cruciate ligament (ACL) reconstruction predictably restores sagittal plane knee stability, however its inability to replicate a complex fan-shaped ligament of multiple fascicles, along with deficient restoration of normal rotational knee kinematics, results in failure to reverse a high risk for premature post-traumatic osteoarthritis. Although arthroscopic repair for acute ACL femoral avulsions is proposed to counter these deficiencies, the risk of early failure following non-healing, along with lack of convincing evidence of efficacy has impeded its universal acceptance. Moreover, since ACL repair needs to be performed in the acute phase following injury, it has an increased risk of developing arthrofibrosis, besides precluding any possibility to achieve natural healing of an ACL avulsion with non-operative treatment. The technique of biological internal bracing with remnant repair incorporates the advantages of both reconstruction and repair, and is indicated for patients with persistent ACL deficiency in the subacute phase (6-12 weeks) following an ACL femoral avulsion. This operation essentially involves two steps. The step of biological internal bracing is similar to a conventional ACL reconstruction using a small diameter hamstring graft that is targeted to the centre of the anteromedial ACL bundle on the femur, whereas the tibial socket is located posteriorly within the ACL tibial footprint so as to preserve the anterior fan-shaped morphology of the ACL tibial insertion. The second step involves repairing the remnant ACL tibial stump using one of three techniques. Although technically more complex than an ACL reconstruction, this novel technique provides native anatomy restoration with potential biomechanical and functional advantages, and should be considered for unhealed subacute ACL avulsion injuries.