Gamekeeper's Thumb in a Competitive Bowler: A Case Report

Case Diagnosis: Hyperextension of the first metacarpophalangeal joint (MCPJ) in the radial plane with injury to the ulnar collateral ligament (UCL) (Gamekeeper’s Thumb).

Case Description or Program Description: Patient is a 37 year-old female bowler presenting right thumb pain and numbness. Pain began gradually after repeated bowling competitions over approximately 4 months. She has associated intermittent paresthesia accompanying her pain in the ulnar aspect of her first MCPJ. Physical examination revealed intact bilateral motor strength and sensation to light touch and tenderness to palpation over the right first MCPJ. Hand x-ray taken was negative for avulsion fracture. Electromyography testing was negative for any injury to the radial/median/ulnar nerves.

Setting: Single center outpatient physiatry office.

Assessment/Results: Patient was treated with a thumb spica splint. At 2 months follow up, her pain had resolved and she was back to bowling.

Discussion (relevance): Gamekeeper’s thumb was named after small game hunters that would forcibly twist the neck of injured game, eventually causing a chronic injury. Today, partial UCL tears are most commonly caused by skiing accidents, while complete UCL ruptures often result from non-sports related falls. In about 50% of complete ruptures of the UCL, the adductor pollicis aponeurosis will interpose between the UCL and MCPJ; the result of this process is termed a Stener lesion, a complication that requires surgery to allow for proper healing. Gamekeeper’s thumb typically presents with pain at the ulnar aspect of the first MCPJ and laxity with valgus stress. Plain x-ray can be helpful to identify avulsion fracture or bony abnormality. Electrodiagnostic testing can be used to rule out any neuropathic etiologies. Ultrasound and magnetic resonance imaging are both sensitive imaging studies to assess the degree of injury to the UCL.

Conclusions: Gamekeeper's thumb is an often overlooked diagnosis that can occur in any activity that results in hyperextension in the radial plane of the first UCL, including bowling.