UCSF

Purpose

To describe differences in radiographic and magnetic resonance imaging (MRI) findings between adult and pediatric patients with known primary anterior cruciate ligament (ACL) injuries.

Methods

We performed a retrospective analysis of surgical patients with a history of ACL tears treated at our institution over a 7-year period. Patients were divided into 2 cohorts based on age (≤15 years and ≥21 years). Patients' radiographs and MRI studies were used to compare features including fracture incidence, bone bruise pattern, associated ligamentous injuries, and meniscal injuries between the 2 groups. Proportions of associated findings were analyzed using the 2-proportion z test.

Results

Within our cohorts of 52 sex-matched pediatric and adult patients, we found that pediatric patients were more likely to have radiographic evidence of fracture (P = .001) and MRI evidence of lateral femoral condylar bone bruising (P = .012). Adult patients had higher rates of medial femoral condylar bruising (P = .016) and medial proximal tibial bruising (P = .005), as well as popliteal fibular ligament injuries (P = .037), identified on MRI.

Conclusions

In this study, we identified differences in bone bruise patterns between pediatric and adult patients with primary ACL tears. Pediatric patients were more likely to have radiographic evidence of fracture and MRI evidence of lateral femoral condylar bone bruising. Adult patients were more likely to show medial femoral condylar and medial proximal tibial bone bruising, as well as popliteal fibular ligament injuries.

Level of evidence

Level IV, prognostic case series.