Rehab after a Revision ACL Reconstruction
Reconstruction of the anterior cruciate ligament (ACL) is widely accepted as the treatment of choice for individuals with functional instability due to an ACL-deficient knee. It is estimated that anywhere between 60,000 and 75,000 ACL reconstructions are performed annually in the United States, although this number may be as high as 350,000. Despite the fact that nearly 90% of index ACL reconstructions are performed by surgeons who do fewer than 10 reconstructions per year, the overall success rate of the operation is high, ranging from 75% to 95%. Nevertheless, between 3,000 and 10,000 revision ACL surgeries are performed each year, underlying the significant potential for failed ACL reconstruction (ACLR). As adolescents maintain their participation in sports and older athletes extend their playing days, the number of index ACL injuries continue to escalate each year.6 Accordingly, as patient expectations and functional demands increase, the number of ACLR failures, with subsequent revision ACL surgery, will likely show a similar trend.
When evaluating a patient with persistent complaints following an index ACL surgery, the first and most important step is to define what constitutes a failure of the ACLR. Currently, there is a lack of general consensus on what criteria define a failed ACLR. A low correlation exists between the patient’s perception and the surgeon’s evaluation of knee stability following reconstruction. Safran and Harner proposed a definition of ACLR failure with the attempt to combine both subjective data gathered from the patient and objective data gathered by the clinician. They defined failure as “functional instability with activities of daily living or sports and the knee shows increased laxity on physical examination and instrumented testing.” Based on this definition, it is estimated that approximately 8% of patients undergoing primary ACLR will develop recurrent instability and proceed to graft failure.
The evaluation, diagnosis, treatment and rehabilitation of failed ACLR is complex. Successful revision ACLR requires an accurate diagnosis as to the cause of failure, appropriate pre-operative work-up, careful patient selection, a well-executed surgical plan, and individualized rehabilitation protocols. Patient counseling and management of pre-operative expectations are critically important. In general, it has been widely reported that the outcomes after revision ACLR are inferior to those following primary ACLR. Even in the presence of objective evidence of knee stability, subjective outcomes may remain poor, possibly due to the declining status of the meniscus and articular surfaces. Return to pre-injury level of play is also less predictable after revision ACLR. Despite these challenges, the outcome of revision ACLR can be quite successful if the treating team is attentive to detail, meticulous in preoperative evaluation, and adherent to sound operative and rehabilitative principles.