Complications in Anterior Cruciate Ligament Revision Reconstruction

Introduction

With approximately 200,000 anterior cruciate ligament (ACL) tears per year, primary anterior cruciate ligament reconstruction (ACLR) is one of the most common orthopedic procedures performed, and accounts for $1 billion to $2 billion dollars in healthcare per year. ACL tears frequently result from sports-related injuries, especially those activities with noncontact pivoting or cutting motions, and many of the patients are younger and expect a full return to their previous level of activity. Success with primary ACLR ranges from 75% to 97%, and although outcomes are generally satisfactory, failures do occur in sizeable numbers given the high volume of procedures performed. Unfortunately, revision ACLR (RACLR) is not associated with the same level of success as primary ACLR. The success rate for RACLR is reported to be only 65% to 75%, with return to previous levels of activities seen in a mere 54% of patients. Despite the humbling literature, there is some evidence to support similar results in RACLR when compared with primary ACLR. Failures may stem from a variety of sources throughout the preoperative, intraoperative, and postoperative periods causing graft rupture and persistent instability. Ultimately, surgery is considered a failure when the graft fails to effectively reestablish a restraint to anterior tibial translation and rotational stability. Rehabilitation becomes prolonged with RACLR, and patient expectations must be tempered. Given the inferior results with RACLR, it becomes crucial for the orthopedic surgeon to minimize the risks of perioperative complications. Successful navigation of RACLR requires scrutinizing the previous surgery and the reason for primary failure as to prevent repetition of previous results. Broadly speaking, reasons for failure of the primary reconstruction may include technical error in tunnel placement, inappropriate graft material, insufficient graft incorporation, the presence of coexisting cartilage or ligamentous injuries, recurrent trauma, limb malalignment, problems with rehabilitation, and limited patient compliance. Oftentimes the exact etiology of graft failure is difficult to determine or may be a combination of factors. However, failures may be characterized as early (occurring within 6 months of surgery) or late (occurring approximately 1 year after surgery). Early failures are thought to be associated with surgical errors, overaggressive rehabilitation, failure of the graft to incorporate, or return to sports too early after the reconstruction. Injuries later than 1 year may result from recurrent trauma to the knee.

As with any revision surgery, initial workup of the patient should include a thorough history and clinical examination. Ligamentous laxity should be compared with the contralateral knee. Anterior-posterior and lateral radiographs are helpful in determining the bony anatomy of the knee joint as well as tibial slope. Standing radiographs may reveal limb malalignment. If a corrective osteotomy is necessitated, one should consider factors that may impair bony healing, another source of complications in revision surgery. Advanced imaging such as computed tomography (CT) or magnetic resonance imaging (MRI) are invaluable in determining the position of previous hardware, tunnel position and size, evidence of osteolysis, and degenerative changes to the joint. MRI provides information about the overall quality of the graft and important information regarding concomitant injury to other soft tissue structures including the other ligaments, menisci, and cartilage. Whether or not to stage procedures in RACLR must be considered, and the decision is heavily based on graft availability and selection, position of bony tunnels, size of the bony tunnels with or without osteolysis, ability to fixate the graft, and the healing milieu. Surgeons may construct a timeline to stratify complications into those that occur preoperatively, intraoperatively, and postoperatively to be prepared to navigate these possible complications and maximize patient outcomes with RACLR.