Classic history and presentation: Humeral shaft fractures are classically seen in patients with a history of direct or indirect trauma to the humeral shaft. Patients most commonly present in the context of a fall, motor vehicle accident, or injury sustained while playing sports. Patients often present with pain in the proximal arm with overlying soft tissue swelling and/or ecchymosis. The arm may have visible deformities, such as shortening, abnormal curvature, and soft tissue breakdown.
Prevalence: Humeral shaft fractures constitute 3%-5% of all fractures. Peak incidence is bimodal, seen in young male patients aged 20-30 years in the context of trauma and in female patients older than 50 with osteoporosis.
Risk factors: Conditions that increase risk for pathologic factors such as osteoporosis.
Pathophysiology: Humeral shaft fractures are caused by high-impact trauma either directly or indirectly applied to the humeral shaft. Radiographs show that 34% of fractures occur in the proximal third, 46% occur in the middle third, and 20% occur in the distal third.
Grade / classification system: Fractures are commonly categorized using the OTA/AO classification. In this system, the bone, bone segment, and type of fracture are organized alphanumerically.
- The humerus is identified by the number 1.
- The fracture along the humerus is localized to the diaphyseal segment with the number 2.
- The type of fracture is classified as type A for simple fractures, type B for wedge fractures, and type C for complex fractures.
