Ulnar stress reaction in an axillary crutch user

Ulnar stress fractures have been reported in athletes performing repetitive, high-impact activities, such as baseball pitchers and gymnasts. Crutch-assisted walking also results in cyclical forearm loading. We report the first case of ulnar stress reaction due to axillary crutch use. A 23-year-old right-handed woman experienced right forearm pain and imaging confirmed a right ulnar stress injury. The patient was also found to have mild hypercortisolism, low bone mass and vitamin D deficiency. Crutches were discontinued and physical therapy to normalise weight bearing through the left leg was prescribed. The patient's right forearm symptoms resolved and she was started on oral vitamin D supplementation. Axillary crutch use may result in ulnar stress injury, particularly in vulnerable populations. The addition of an upper extremity injury to someone with impaired mobility may compound disability. As such, clinicians should be aware of the clinical presentation of ulnar stress fractures in the long-term axillary crutch user.