The rate of subsequent surgery and predictors after anterior cruciate ligament reconstruction: two- and 6-year follow-up results from a multicenter cohort.

BACKGROUND Subsequent surgeries have a profound effect on patient satisfaction and outcome after primary anterior cruciate ligament reconstruction (ACLR). There have been no prospective studies to date describing the rate and predictors (surgical and patient variables) of all subsequent knee surgeries at short-term and midterm follow-up along with analyses of surgical and patient variables that are associated with subsequent surgeries. PURPOSE To report the rate and predictors of all subsequent surgeries at short-term and midterm follow-up along with associated patient variables. STUDY DESIGN Case-control study; Level of evidence, 3. METHODS A total of 980 patients (540 male) were prospectively enrolled in a Multicenter Orthopaedic Outcomes Network (MOON) cohort from January 2002 to December 2003. The 2- and 6-year follow-up information for subsequent procedures was obtained. Operative reports were obtained, and all procedures were categorized. RESULTS One hundred eighty-five patients underwent a subsequent surgery on the ipsilateral leg (18.9%) and 100 on the contralateral knee (10.2%) at 6-year follow-up. On the ipsilateral knee, there was a 7.7% rate of ACL revisions, a 13.3% rate of cartilage procedures, a 5.4% rate of arthrofibrosis procedures, and a 2.4% rate of procedures related to hardware. For the contralateral knee, there was a 6.4% rate of primary ACL ruptures. Younger age at the index surgery and the use of allografts were predictors (risk factors) for subsequent surgery. Revision ACLR, female sex, body mass index, and surgical exposure were not significant predictors. CONCLUSION At 6-year follow-up, 18.9% of patients who had undergone ACLR underwent subsequent surgeries on the ipsilateral knee. The rates between an ipsilateral ACLR graft versus a contralateral normal ACL tear were similar (7.7% vs 6.4%, respectively). Younger age and the use of allografts were risk factors for subsequent surgery.