Background: The incidence of anterior cruciate ligament (ACL) tears in skeletally immature patients with an ACL bone contusion pattern has been sparsely investigated. The purpose of this study is to investigate whether physeal status has an influence on the likelihood of sustaining an ACL tear when classic bipolar ACL bone bruising pattern is present.
Methods: Magnetic resonance imaging reports were queried for "contusion" on all patients between 6 and 22 years between 2015 and 2019. Images were reviewed to denote all intra-articular pathology and the physeal status of the femur and tibia. The primary outcome was the incidence of ACL tears in patients with the presence of bipolar bone contusions. Fischer exact testing was used to determine associations.
Results: Of 499 patients included, 269 of those had bipolar bone contusions. Patients with bipolar bone contusions and ACL tears had a shorter duration between injury and imaging date compared with patients with ACL tears without bipolar bone contusions (6.9 vs. 38.6 d, P =0.05). Patients with an open femoral physis had a higher likelihood of having an intact ACL despite the presence of bipolar bone contusions than patients with a closed femoral physis (10.8% vs. 1.0%, P <0.001). Of patients with bipolar bone contusions, those with an intact ACL were younger than patients with an ACL tear (14.6 vs. 16.4, P =0.017).
Conclusions: Although bipolar bone contusions of the central lateral femoral condyle and posterior lateral tibial plateau are typically found after ACL injury, these bipolar contusions can be found concomitantly with an intact ACL and were more often found in relatively younger patients. Patients who have an open femoral physis have a higher likelihood to have an intact ACL despite the presence of bipolar bone contusions compared with patients who have a closed femoral physis.
Level of evidence: Level IV-cross-sectional.
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