Ulnar Collatreal Ligament Injuries: “Skier’s Thumb”

51 Ulnar Collateral Ligament Injuries: “Skier’s Thumb”

Kevin D. Plancher

History and Clinical Presentation

A 24-year-old left hand dominant woman presents with a swollen and painful left thumb. While skiing the patient felt a sharp pain in her thumb at the metacarpophalangeal (MP) joint when she put her hand out to stop her fall. She recalls her thumb landed in an outstretched fashion in the snow and was pulled backward and out of the palm. She is unable to use her thumb secondary to pain. She denies any previous history of trauma to her hand or thumb.

Physical Examination

The patient demonstrated tenderness along the ulnar collateral ligament (UCL) of the MP joint of the thumb. She has localized swelling and ecchymosis. Stress testing without lidocaine of the UCL at both full extension and flexion resulted in 35-degree laxity without an end point, and greater than 15 degree difference from the noninjured contralateral side (Fig. 51–1A,B). No crepitus with joint motion can be detected on physical examination.

Figure 51–1. (A) Torn ulnar collateral ligament (UCL) of the thumb. (B) Physical exam of incompetent UCL. (C) Corresponding x-ray of incompetent UCL.

Figure 51–2. (A) Normal lateral radiograph in an uninjured person. (B) Radiograph demonstrating volar subluxation.

PEARLS

Delay in treatment beyond 3 to 5 weeks promotes instability even with secondary procedures.
Volar subluxation on the lateral x-ray may be the only clue to this injury.
Physical exam may show a supinated digit as the only clue to this injury.
Chronic reconstructions with palmaris longus has conflicting reports in the literature, while an MP fusion for a laborer may be a better alternative.

Diagnostic Studies

Radiographs, Robert’s view, anteroposterior (AP), and lateral, were obtained, and no fracture was seen in the thumb column. Lateral x-ray revealed volar subluxation of the MP joint (Fig. 51–2), and the stress testing under fluoroscopic guidance reveals abduction of the MP joint without an end point (Fig. 51–3). Local anesthetic may be necessary for accurate stress radiographs if pain is intolerable. An injured thumb that demonstrates more than 30 degrees of instability compared with the contralateral and uninjured side indicates a complete UCL rupture.