Which Preoperative Factors, Including Bone Bruise, Are Associated With Knee Pain/Symptoms at Index Anterior Cruciate Ligament Reconstruction (ACLR)? A Multicenter Orthopaedic Outcomes Network (MOON) ACLR Cohort Study

Background: Increased knee pain at the time of anterior cruciate ligament reconstruction may potentially predict more difficult rehabilitation, prolonged recovery, and/or be predictive of increased knee pain at 2 years. Hypothesis: A bone bruise and/or other preoperative factors are associated with more knee pain/symptoms at the time of index anterior cruciate ligament reconstruction, and the presence of a bone bruise would be associated with specific demographic and injury-related factors. Study Design: Cohort study (prevalence); Level of evidence, 2. Methods: In 2007, the Multicenter Orthopaedic Outcomes Network (MOON) database began to prospectively collect surgeon-reported magnetic resonance imaging bone bruise status. A multivariable analysis was performed to (1) determine if a bone bruise, among other preoperative factors, is associated with more knee symptoms/pain and (2) examine the association of factors related to bone bruise. To evaluate the association of a bone bruise with knee pain/symptoms, linear multiple regression models were fit using the continuous scores of the Knee injury and Osteoarthritis Outcome Score (KOOS) symptoms and pain subscales and the Short Form 36 (SF-36) bodily pain subscale as dependent variables. To examine the association between a bone bruise and risk factors, a logistic regression model was used, in which the dependent variable was the presence or absence of a bone bruise. Results: Baseline data for 525 patients were used for analysis, and a bone bruise was present in 419 (80%). The cohort comprises 58% male patients, with a median age of 23 years. The median Marx activity level was 13. Factors associated with more pain were higher body mass index (P<.0001), female sex (P=.001), lateral collateral ligament injury (P=.012), and older age (P=.038). Factors associated with more symptoms were a concomitant lateral collateral ligament injury (P=.014), higher body mass index (P<.0001), and female sex (P<.0001). Bone bruise is not associated with symptoms/pain at the time of index anterior cruciate ligament reconstruction. None of the factors included in the SF-36 bodily pain model were found to be significant. After controlling for other baseline factors, the following factors were associated with a bone bruise: younger age (P=.034) and not jumping at the time of injury (P=.006). Conclusion: After anterior cruciate ligament injury, risk factors associated with a bone bruise are younger age and not jumping at the time of injury. Bone bruise is not associated with symptoms/pain at the time of index anterior cruciate ligament reconstruction.