Bone Contusions After Acute Noncontact Anterior Cruciate Ligament Injury Are Associated With Knee Joint Laxity, Concomitant Meniscal Lesions, and Anterolateral Ligament Abnormality

Purpose: To examine the associated findings with bone contusions in patients after acute noncontact anterior cruciate ligament (ACL) injuries.

Methods: From January 1, 2011, to December 31, 2013, patients who underwent ACL reconstructions performed by the senior author (H.F.) were retrospectively analyzed. Presence and severity of bone contusion were determined from preoperative magnetic resonance images (MRIs) for each anatomic site including the lateral femoral condyle (LFC), lateral tibial plateau (LTP), medial femoral condyle (MFC), and medial tibial plateau (MTP). Multivariable logistic regression was used to calculate adjusted odds ratios (ORs) and 95% confidence intervals (CIs) for the associated findings (demographic data, preoperative physical examinations, concomitant meniscal lesions, intra-articular cartilage damages, and anterolateral ligament [ALL] abnormality) with bone contusions. Outcomes included the presence of bone contusions at each anatomic site (LFC, LTP, MFC, and MTP) and severity of lateral bone contusions (moderate/severe vs none/minimal).

Results: Among the 697 consecutive cases, 193 were finally selected. Prevalence of bone contusions seen on MRI was as follows: 60.6% LFC, 73.1% LTP, 6.2% MFC, and 21.2% MTP. Presence of bone contusions at LFC and LTP were significantly associated with high-grade (grade II and III) pivot-shift (OR_LFC, 7.39; 95% CI, 1.99, 27.44; OR_LTP, 2.52; 95% CI, 1.02, 6.24), concomitant lateral meniscal lesions (OR_LFC, 3.23; 95% CI, 1.93, 11.31; OR_LTP, 10.17; 95% CI, 1.86, 55.47), and ALL abnormality (OR_LFC, 3.79; 95% CI, 1.46, 9.84; OR_LTP, 4.47; 95% CI, 1.28, 15.58). However, none of the above associated findings was correlated with the presence of bone contusions at MFC and MTP. Furthermore, moderate/severe lateral bone contusions were still found to be significantly associated with high-grade (grade II and III) pivot-shift (OR_LFC, 14.89; 95% CI, 2.71, 82.11; OR_LTP, 6.76; 95% CI, 1.27, 36.06), concomitant lateral meniscal lesions (OR_LFC, 17.34; 95% CI, 3.91, 76.87; OR_LTP, 22.01; 95% CI, 5.08, 95.42), and ALL abnormality (OR_LFC, 4.02; 95% CI, 1.33, 12.09; OR_LTP, 2.57; 95% CI, 1.09, 6.04).

Conclusions: For acute noncontact ACL injury, both the presence and the severity of lateral bone contusions are associated with high-grade (grade II and III) pivot-shift, concomitant lateral meniscal lesions, and ALL abnormality.

Level of evidence: Level III, retrospective comparative study.