Clinical evaluation vs magnetic resonance imaging of the skier's thumb: A prospective cohort of 30 patients.

INTRODUCTION: A skiers thumb, or a partial or complete rupture of the ulnar collateral ligament (UCL) is a clinical diagnosis. Swelling, pain, natural left-right difference and inexperience of a young physician can cause difficulty to correctly diagnose this injury. However, our theory is that any physician, given the correct instructions, should be able to diagnose this injury solely on clinical findings, without the necessity of additional imaging.

MATERIAL AND METHODS: In a large Dutch teaching hospital, physicians (residents with working experience of 6months-3years) working at the ER received instructions for physical examination. Patients >18 years, with an injury <1 week old, suspected of a true skier's thumb had an MRI reported by two independent radiologists to confirm the diagnosis.

RESULTS: Thirty patients were included. Seven patients had no fixed endpoint (23%), all had a complete ligamentous rupture of the UCL on MRI, of which three patients had a Stener lesion. Fifteen patients (50%) met with the criteria  >35° laxity in extension of MCP/ >20° laxity in 30° flexion of the MCP. Of these, thirteen patients (81%) had a complete rupture (nine Stener lesions (56%)). One patient had a partial injury and one patient had no UCL-injury. Eight patients (27%) had inconclusive results during physical examination. Of these, two had a complete rupture (40%, 1 Stener). Three patients had a partial rupture and three patients had an intact UCL.

CONCLUSION: A skier's thumb can be diagnosed by any resident when correctly instructed. Additional imaging when diagnosing a skier's thumb should be reserved in cases when physical examination remains inconclusive.