(Kiosk 2) Throwing Your Arm Out: An Oblique Distal Humerus Fracture Following a Baseball Throw

Case Diagnosis: An oblique distal humerus fracture following a baseball throw

Case Description or Program Description: A 27-year-old male without medical history presented to the emergency room with right elbow pain after throwing a baseball. He immediately heard a pop and endorsed pain proximal to his elbow. He experienced clicking with elbow range of motion. Physical exam exhibited tenderness proximal to his elbow, localized swelling, and muscle strength limited by pain.

Setting: Tertiary-care teaching hospital

Assessment/Results: Imaging demonstrated an acute oblique posterolaterally displaced fracture of the right distal humeral diaphysis with mild surrounding soft tissue swelling. Orthopedics performed closed fracture reduction and placed a coaptation splint. He was managed non-operatively, with non-weight bearing of his right upper extremity. He was transitioned to a Sarmiento brace after one week. Orthopedics recommended home exercises, including elbow, wrist, and finger range of motion at three weeks post-fracture. He began weight bearing after three weeks, discontinued the Sarmiento brace, and started physical therapy. He was evaluated by physiatry, with decreased active range of motion and triceps strength. He participated in six weeks of physical therapy with improved elbow range of motion and triceps strength.

Discussion (relevance): Although most humeral shaft fractures are traumatic, less commonly non-traumatic fractures occur with throwing motions. Throwing is a complex motion, involving shoulder and elbow movements simultaneously. Multiple muscle groups act synergistically and antagonistically, inflicting torsional forces on the humerus throughout the throwing motion. These fractures typically occur during the cocking or acceleration phase of throwing. A thrower’s fracture presents as an external rotation spiral fracture of the humerus, with symptoms including localized pain, swelling, and bruising. Patients often experience a pop or snap and have a visible deformity at the site.

Conclusions: Thrower’s fractures are a unique cause of non-traumatic humeral shaft fractures in athletes. Early rehabilitation is crucial to maintain range of motion and strength in the affected extremity.