Which Preoperative Factors, Including Bone Bruise, Are Associated With Knee Pain/Symptoms at Index Anterior Cruciate Ligament Reconstruction (ACLR)?
Authors: Dunn Warren R. , Spindler Kurt P. , Amendola Annunziato , Andrish Jack T. , Kaeding Christopher C. , Marx Robert G. , McCarty Eric C. , Parker Richard D. , Harrell Frank E. , An Angel Q. , Wright Rick W. , Brophy Robert H. , Matava Matthew J. , Flanigan David C. , Huston Laura J. , Jones Morgan H. , Wolcott Michelle L. , Vidal Armando F. , Wolf Brian R. ,   The MOON ACL Investigation
Published: July 2010

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.