Multiligament Knee Injuries in Adolescents: Distinct Patterns Based on Energy Mechanisms and Polytrauma Status

Author(s): Allan K Metz, Collin DR Hunter, Joseph Featherall, Natalya McNamara, Cody T McGrale, Pat Greis, Travis G Maak, Stephen K Aoki, Antonio Klasan, Justin J Ernat

Purpose: Characterize differences in ligamentous injury patterns in adolescents with MLKIs by different mechanisms and polytrauma status, with the hypothesis that high-energy (HE) and polytrauma (PT) patients would have more severe injuries.

Materials and Methods: Demographics, clinical characteristics, radiographic findings, and intraoperative variables were obtained on surgical MLKIs in the adolescent population from a single tertiary-care institution between June 2008 through October 2022. HE versus lowenergy (LE) and PT versus non-polytrauma (NPT) mechanisms were stratified. Subgroup comparisons were made based on body mass index, age, sex, number/type of ligaments injured, and surgeries performed. Statistical analysis included t-test and Chi-square analyses.

Results: A total of 38 adolescent MLKI patients were included (mean age 16.0 ± 1.6 years, body mass index 24.6 ± 4.3 points, 65.8% male). There was an increased rate of posterior cruciate ligament (PCL; 77.8% vs 24.1%; P = 0.004), lateral collateral ligament (LCL; 77.8% vs 34.5%; P = 0.022), and medial patellofemoral ligament (MPFL) (44.4% vs 10.3%; P = 0.021) injuries in HE vs. LE, respectively. PT compared to NPT cases also had higher rates of LCL (83.3% vs 37.5%; P = 0.038) and MPFL (50.0% vs 12.5%; P = 0.030) injuries. Mean number of ligaments injured (excluding MPFL) were increased in HE vs. LE (3.2 ± 0.7 vs 2.2 ± 0.7; P < 0.001) and PT vs. NPT (3.2 ± 0.8 vs 2.3 ± 0.8; P = 0.014) cases, respectively.

Conclusion: MLKIs resulting from HE mechanisms were associated with increased rates of PCL, LCL, and MPFL injuries, with PT patients having increased rates of LCL and MPFL injuries. HE and PT patients experienced a greater number of injured ligaments than LE and NPT patients. LCL injuries were associated with increased rates of injury in both groups and should be scrutinized in these patients during workup.

Level of Evidence: Level IV: Retrospective Case Series