eMedicine Specialties > Orthopedic Surgery > Hand & Upper Extremity

Gamekeeper's Thumb

Author: Matthew Hannibal, MD, Staff Physician, Department of Orthopedics, St Mary's Medical Center
Coauthor(s): Daniel Roger, MD, Assistant Professor, Department of Orthopedics, Catholic Medical Center of Brooklyn and Queens, New York Medical College
Contributor Information and Disclosures

Updated: Aug 6, 2009

Introduction

History of the Procedure

Campbell originally coined the term gamekeeper's thumb in 1955,¹ because this condition was most commonly associated with Scottish gamekeepers, especially rabbit keepers, in whom the injury was work related. The injury occurred as the men sacrificed game such as rabbits; the animals' necks were broken between the ground and the gamekeeper's thumb and index fingers. As a result, a valgus force was placed onto the abducted metacarpophalangeal (MCP) joint, leading to an ulnar collateral ligament (UCL) injury and resulting in instability that was accompanied by pain and weakness of the pinch grasp. 

In the present day, this type of injury is typically more acute. The most common mechanism is a skier landing on the ground with his or her hand braced on a ski pole, causing a valgus force on the thumb.² The term skier's thumb reflects the acute nature of the injury.^3,4,5,6,7

For excellent patient education resources, visit eMedicine's Hand, Wrist, Elbow, and Shoulder Center and Sports Injury Center.

Problem

Gamekeeper's thumb is a clinical instability of the first MCP joint caused by an insufficiency of the UCL in the MCP of the thumb. Because the stability of the thumb is important for prehension, treatment is directed toward optimizing the healing of the ligament to restore its full function.^8,9,10,11,12

Recent studies

In a French study, Gherissi et al evaluated echography (ultrasonography) to diagnose Stener lesions in 25 gamekeeper's thumbs from March 2005 to March 2007. They found that ultrasonography is useful in identifying Stener lesion in the emergency department because it is available, cheap, noninvasive, and dynamic. Ultrasonography was ultrasonographer-dependent and ultrasonogram-dependent. The author's study revealed the advantage of using ultrasound with tissue harmonic imaging.⁸

Chuter et al, over a 10-year period, studied 127 patients who underwent surgical repair of an acute thumb ulnar collateral ligament (UCL) rupture for clinically unstable injuries or displaced avulsion fractures. Ultrasound was used when clinical diagnosis was uncertain. The male-to-female ratio was 3:2, with a mean age of 40 years (range, 12-81 y). Most of the injuries (³ 66%) were hyperextension or abduction injuries. The most common cause of injury was a fall (49%), followed by sports injuries (skiing injuries accounted for only 2.4% of injuries). Ultrasound was 92% sensitive for UCL ruptures (positive predictive value, 99%). Over 99% of patients had a UCL rupture confirmed at surgery. Other findings included avulsion fractures (21%), dorsal capsular tears (57%), and dorsal capsule infolding (29%).¹¹

Frequency

Gamekeeper's thumb is a common injury. The incidence is increased in skiers, but it does not depend on the type of ski pole used. No sex-related proclivity exists.

Etiology

Gamekeeper's thumb is caused by a valgus force that is directed on the thumb metacarpophalangeal joint and produces a failure of the ulnar collateral ligament. Falls on an abducted thumb and the fall of a skier against a planted ski pole are common mechanisms.

Pathophysiology

For a discussion about the anatomy of the metacarpophalangeal (MCP) joint and ulnar collateral ligament (UCL), please see Relevant Anatomy, below.

A Stener lesion occurs when the adductor aponeurosis becomes interposed between the ruptured UCL and its site of insertion at the base of the proximal phalanx. Thus, the distal portion of the ligament retracts and points superficially and proximally. A rupture of the proper and accessory collateral ligaments must occur for this injury to happen. The UCL no longer contacts its area of insertion and cannot heal.

Presentation

The injured thumb should be evaluated for swelling and pain at the ulnar aspect of the metacarpophalangeal joint. Ecchymosis is frequently seen. A palpable mass on the ulnar aspect of the MCP joint may represent the retracted ulnar collateral ligament stump that is displaced proximally and dorsally relative to the adductor aponeurosis. The uninjured thumb should be evaluated first to assess its range of motion (ROM) and valgus stability in both extension and 30º flexion.

The range of flexion and extension of the thumb MCP joint varies considerably. The variation of normal joints can include ROMs of 5-115º of flexion and extension. In full extension, valgus laxity averages 6º and increases to an average of 12º in 15º of flexion.

The accessory collateral ligament may remain intact, and gross instability may be absent. The thumb should be placed in 30° flexion and tested for valgus instability in this position. However, this maneuver should be performed only after radiographic findings rule out a gamekeeper's fracture.

Although a gamekeeper's fracture is a contraindication to stress testing, a nondisplaced avulsion fracture is not. If the patient's pain is severe, the joint may be anesthetized with a lidocaine injection before the stress testing. A laxity of 30º or one that is 15º more than that on the uninjured side represents a ruptured proper collateral ligament in this position (the proper collateral ligament runs from the metacarpal head to the volar aspect of the proximal phalanx).^13,4 A supination deformity of the MCP joint, which may be visualized, can be associated with the volar subluxation of the MCP joint and suggests instability.

A Stener lesion can be present only when both the proper and accessory collateral ligaments are ruptured. In more than 80% of complete ruptures of the UCL, a Stener lesion is present, whether it is palpable or not. Stress testing with the thumb in the extended position is the best test for determining the competence of the accessory collateral portion of the UCL. Again, valgus laxity of more than 30º or a laxity that is 15º more than that on the uninjured side suggests rupture of this portion of the ligament.^13,4 If valgus laxity of the MCP joint is present in both the flexed and extended positions, complete UCL rupture should be suspected.

Indications

Nonsurgical treatment can be considered for partial tears of the UCL, that is, grade I or grade II tears. These tears usually involve an isolated rupture of the proper collateral ligament.

Complete ruptures of the UCL can be determined by means of physical examination, including stress testing. Radiographic stress testing can be performed, but the evaluating surgeon should perform these tests because radiographic stress test findings can be misleading.

In pediatric gamekeeper's thumb, the injury usually involves a Salter-Harris type III fracture of the thumb proximal phalanx.⁵ If the fragment is displaced by less than 2 mm, nonsurgical management is indicated. For greater displacement, the fracture should be opened and reduced.

Occasionally, significant ligamentous injury may occur without immediate gross instability, which can be masked by swelling and muscle spasm. At this point, a repeat examination can be performed after 1 week; if the swelling persists and motion has not been regained, surgical fixation may be considered.

Relevant Anatomy

The UCL is a 4- to 8-mm X 12- to 14-mm band that originates from the metacarpal head and inserts into the medial aspect and base of the proximal phalanx of the thumb. Occasionally, when the UCL is strained, it avulses the bone at its insertion and leads to a gamekeeper's fracture (see Images 1-2).

Contraindications

In gamekeeper's thumb, no absolute contraindications to surgery exist.

Relative surgical contraindications for gamekeeper's thumb include the following:

• The patient is too infirm to tolerate surgery, regardless of whether a complete UCL tear is present.
• Gamekeeper's thumb, if present in a child, with less than 2 mm of displacement of the Salter-Harris type III fracture
• Chronic instability of the thumb due to a chronic ulnar collateral ligament rupture

Chronic instability of the thumb due to a chronic UCL rupture is difficult to treat, and repair using the capsuloligamentous structures of the ulnar border of the metacarpophalangeal joint has had limited success. Even surgical repair that is performed 6 weeks after the complete UCL rupture has limited success. Essentially, the longer a complete rupture of the UCL exists, the smaller the possibility of stability restoration with anatomic repair (see Complications, below).

Some surgeons have reported success with the dynamic transfer of a tendon such as the adductor pollicis from its insertion on the ulnar sesamoid to the ulnar base of the proximal phalanx. Other surgeons have reported success with the use of static tendon transfers, which have the theoretical advantage of an inherent blood supply if some continuity of the tendon with its musculotendinous unit is preserved. MCP fusion has been recommended by some surgeons in cases of chronic gamekeeper's thumb; in some cases, this procedure is reserved for use in patients who have concomitant osteoarthritis.

• Search for CME/CE on This Topic »

• Gamekeeper's Thumb (Sports Medicine)
• Gamekeeper Thumb (Emergency Medicine)
• Hand, Thumb Fracture and Dislocations (Plastic Surgery)
• Hand, Rheumatoid Hand (Plastic Surgery)

• Repetitive Motion Injuries Overview
• Hand, Wrist, Elbow, and Shoulder Center
• Sports Injury Center