MR imaging of complications of anterior cruciate ligament graft reconstruction.

During the past 3 decades, graft reconstruction of the anterior cruciate ligament (ACL) has become an accepted treatment for symptomatic ACL deficiency. The goal of surgery is to prevent joint instability, which may further damage articular cartilage and menisci. Graft failure is defined as pathologic laxity of the reconstructed ACL. The prevalence of recurrent instability after primary ACL reconstruction ranges from 1% to 8%. Early failures, those that occur within the first 6 months, often are secondary to poor surgical technique, failure of graft incorporation, or errors in rehabilitation. Late failures, those that occur more than 1 year after surgery, likely are related to new trauma and graft tearing. Other complications of ACL reconstruction include roof impingement, postoperative stiffness, tunnel widening due to cyst formation, iliotibial band friction syndrome, hardware failure, and infection. Magnetic resonance imaging is the preferred advanced imaging modality for the evaluation of symptomatic ACL graft reconstructions.