The underlying theme throughout this series of studies authored by the Multicenter anterior cruciate ligament (ACL) Revision Study consortium has been to determine the modifiable predictors or risk factors of long-term outcomes of revision ACL reconstruction. The observational studies described and summarized in the manuscript are both clinically relevant and of great interest in finding out the long-term consequences of the intervention and its relationship to the original injury. The successful completion of these studies has important implications for both therapy and future clinical trials. The identification of modifiable risk factors will play an important role in secondary prevention, while the identification of nonmodifiable risk factors will aid us in counseling our patients and making surgical decisions. Thus, we expect a profound clinical impact on patients' care. More importantly, this project represents an important step forward in bringing evidence to bear in clinical decision making in orthopedic surgery.

Background

The factors that lead to patients failing multiple anterior cruciate ligament (ACL) reconstructions are not well understood.

Hypothesis

Multiple-revision ACL reconstruction will have different characteristics than first-time revision in terms of previous and current graft selection, mode of failure, chondral/meniscal injuries, and surgical charactieristics.

Study design

Case-control study; Level of evidence, 3.

Methods

A prospective multicenter ACL revision database was utilized for the time period from March 2006 to June 2011. Patients were divided into those who underwent a single-revision ACL reconstruction and those who underwent multiple-revision ACL reconstructions. The primary outcome variable was Marx activity level. Primary data analyses between the groups included a comparison of graft type, perceived mechanism of failure, associated injury (meniscus, ligament, and cartilage), reconstruction type, and tunnel position. Data were compared by analysis of variance with a post hoc Tukey test.

Results

A total of 1200 patients (58% men; median age, 26 years) were enrolled, with 1049 (87%) patients having a primary revision and 151 (13%) patients having a second or subsequent revision. Marx activity levels were significantly higher (9.77) in the primary-revision group than in those patients with multiple revisions (6.74). The most common cause of reruptures was a traumatic, noncontact ACL graft injury in 55% of primary-revision patients; 25% of patients had a nontraumatic, gradual-onset recurrent injury, and 11% had a traumatic, contact injury. In the multiple-revision group, a nontraumatic, gradual-onset injury was the most common cause of recurrence (47%), followed by traumatic noncontact (35%) and nontraumatic sudden onset (11%) (P < .01 between groups). Chondral injuries in the medial compartment were significantly more common in the multiple-revision group than in the single-revision group, as were chondral injuries in the patellofemoral compartment.

Conclusion

Patients with multiple-revision ACL reconstructions had lower activity levels, were more likely to have chondral injuries in the medial and patellofemoral compartments, and had a high rate of a nontraumatic, recurrent injury of their graft.