Full-Thickness Triceps Tears Misdiagnosed as Olecranon Bursitis: A Case Report

Full thickness distal triceps tendon ruptures are a rare injury, and one of the most uncommon of all tendinous ruptures. This injury occurs typically as an avulsion from the osseous tendon insertion, but may also occur at the myotendinous junction, or within the triceps muscle belly. Diagnosis of acute triceps tendon rupture can be challenging and is frequently misdiagnosed. Misdiagnosis prolongs disability and adds significant complexity to management, as the primary repair of the ruptured tendon is optimal when performed within three weeks of the injury. We present a case of a full-thickness triceps tendon rupture that was originally diagnosed and treated as an olecranon bursitis, which led to delayed surgical repair. Consequences of full-thickness triceps tendon rupture misdiagnosis include prolonged disability, increased complexity of management, and increased risk of suboptimal outcomes. Strongly consider full-thickness triceps tendon rupture when patients with swelling about the olecranon have concomitant weakness with extension against gravity or resistance relative to the contralateral, uninjured extremity. Focused history and comprehensive musculoskeletal examination are imperative. Advanced imaging may be warranted to aid diagnosis.