Associated capitellar and elbow ligamentous injuries in isolated type 1 radial head fractures based on MRI

Background: In our experience, there is a clinical subset of patients with type 1 radial head fracture who continue to have chronic elbow ache and pain with lifting. As advanced imaging has become more common in orthopaedic practices, there is a heightened awareness of associated injuries and the need to define such relationships. Using MRI, we sought to further describe the incidence of and characterize associated elbow injuries with a focus on insult to the capitellum and elbow collateral ligaments. Methods: Seventeen patients with 17 Mason type 1 radial head fractures underwent MRI of the affected elbow after being diagnosed by physical examination and orthogonal plain radiographs. Results: The incidence of associated elbow injuries was 100%. Capitellar injuries occurred in 82% of patients. Chondral injury occurred in 36%, and subchondral fracture in 6%. Medial collateral ligament (MCL) injury occurred in 88% of patients and in 86% of patients with capitellar injuries. All (100%) elbows had lateral ulnar collateral ligament (LUCL) injury with four complete tears. Conclusions: The incidence of capitellar and MCL injury is higher than previously reported in patients with isolated Mason type 1 radial head fractures. Patients diagnosed with such injuries should be followed closely and evaluated with advanced imaging if there is a failure of motion progression or persistent pain. Long-term clinical outcome of such patients with osteochondral damage of the capitellum should be investigated. Level of Evidence: IV, Case Series, Diagnostic Study.