AUTHOR AND EDITOR INFORMATION

Section 1 of 12  

• Authors and Editors
• Introduction
• Indications
• Relevant Anatomy
• Contraindications
• Workup
• Treatment
• Complications
• Outcome and Prognosis
• Future and Controversies
• Multimedia
• References

INTRODUCTION

Section 2 of 12  

• Authors and Editors
• Introduction
• Indications
• Relevant Anatomy
• Contraindications
• Workup
• Treatment
• Complications
• Outcome and Prognosis
• Future and Controversies
• Multimedia
• References

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. (See also the eMedicine article Gamekeeper Thumb.)

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. (See also the eMedicine article Skier's Thumb.)

For excellent patient education resources, visit eMedicine's Hand, Wrist, Elbow, and Shoulder Center and Sports Injury Center. Also, see eMedicine's patient education article Skier's Thumb and Repetitive Motion Injuries.

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.

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 MCP joint and produces a failure of the UCL. 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 MCP joint and 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. Occasionally, failure of the UCL avulses a small portion of the proximal phalanx at its insertion, leading to a gamekeeper's fracture³; this injury can be subtle or obvious (see Images 1-2), and it can involve a substantial portion of the articular surface of the proximal phalanx. However, a lump or mass over the ulnar aspect of the MCP joint of the thumb does not necessarily imply a fracture; it may be the result of the Stener lesion. (See also the eMedicine article Stener Lesion.)

Clinical

The injured thumb should be evaluated for swelling and pain at the ulnar aspect of the MCP joint. Ecchymosis is frequently seen. A palpable mass on the ulnar aspect of the MCP joint may represent the retracted UCL 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).^{4, 5} 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.^{4, 5} If valgus laxity of the MCP joint is present in both the flexed and extended positions, complete UCL rupture should be suspected.

INDICATIONS

Section 3 of 12  

• Authors and Editors
• Introduction
• Indications
• Relevant Anatomy
• Contraindications
• Workup
• Treatment
• Complications
• Outcome and Prognosis
• Future and Controversies
• Multimedia
• References

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.⁶ 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

Section 4 of 12  

• Authors and Editors
• Introduction
• Indications
• Relevant Anatomy
• Contraindications
• Workup
• Treatment
• Complications
• Outcome and Prognosis
• Future and Controversies
• Multimedia
• References

The MCP joint is a diarthrodial joint that is primarily involved in flexion and extension. The static restraints and some dynamic stabilizers provide joint stability. The static restraints include the proper collateral ligament (mostly in flexion), the accessory collateral ligament (mostly in extension), the palmar plate (mostly in extension), and the dorsal capsule (limited, in flexion). The dynamic stabilizers include the thumb intrinsic and extrinsic muscles. The adductor mechanism is particularly important here, because it inserts onto the extensor expansion through its aponeurosis, which lies superficial to the UCL.

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

Section 5 of 12  

• Authors and Editors
• Introduction
• Indications
• Relevant Anatomy
• Contraindications
• Workup
• Treatment
• Complications
• Outcome and Prognosis
• Future and Controversies
• Multimedia
• References

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 UCL 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 MCP 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. (See also Medscape's CME article Management of Moderate Chronic Pain in Osteoarthritis, as well as the eMedicine articles Osteoarthritis [in the Orthopedic Surgery section] and Osteoarthritis [in the Rheumatology section].)

WORKUP

Section 6 of 12  

• Authors and Editors
• Introduction
• Indications
• Relevant Anatomy
• Contraindications
• Workup
• Treatment
• Complications
• Outcome and Prognosis
• Future and Controversies
• Multimedia
• References

Lab Studies

• No laboratory tests are necessary for the diagnosis of gamekeeper's thumb.
• In cases that require surgical intervention, routine preoperative laboratory workup is indicated.

Imaging Studies

• Standard radiographs
• • Before any manipulation of the thumb, obtain standard anteroposterior (see Image 1), lateral (see Image 2), and oblique radiographs to exclude metacarpal fractures and gamekeeper's fractures.
  • Nondisplaced avulsion fractures that are associated with rupture of the insertion point of the UCL are not contraindications to manipulation. If these fractures were not displaced at the time of injury and greatest stress, they are stable enough for the manipulation of stress testing.
  • Gamekeeper's fractures should not be manipulated, especially those that involve more than 30% of the joint surface and those that are malrotated and/or displaced. Such fractures are indications for surgical intervention.
  • The finding of 3 mm of volar subluxation of the phalanx on the metacarpal is suggestive of complete UCL rupture and instability.
  • Radial deviation of more than 40° in extension and more than 20° in flexion also indicates instability.
• Stress radiographs: Radiographs obtained with the thumb in the flexed and extended positions and with valgus stress at the MCP joint can help the physician to determine the degree of instability of partial tears of the UCL (see Image 3).

Diagnostic Procedures

• Stress testing under local anesthesia (see Images 4-5)
• • The patient often has considerable pain in the thumb, and stressing the MCP joint leads to guarding and misleading findings on examination.
  • The thumb is best examined under local anesthesia, which can be administered in the emergency department or office setting. Often, the administration of 2-3 mL of 1% lidocaine into the MCP joint of the thumb is sufficient to relieve the pain and relax the patient's guarding.
  • If more anesthesia is required, perform a metacarpal or digital block. Some authors recommend the use of an ulnar or median nerve block to negate the effects of the intrinsic muscles. If the injection into the joint relieves the pain, no further anesthesia is necessary.

TREATMENT

Section 7 of 12  

• Authors and Editors
• Introduction
• Indications
• Relevant Anatomy
• Contraindications
• Workup
• Treatment
• Complications
• Outcome and Prognosis
• Future and Controversies
• Multimedia
• References

Medical therapy

Nonsurgical treatment can be considered in partial tears of the UCL, which usually involve an isolated rupture of the proper collateral portion of the ligament. This injury may be treated by immobilizing the thumb in a spica-type cast for 4 weeks (see Images 6-7). The cast should be well molded around the MCP joint, and the interphalangeal (IP) joint can be left free. With appropriate closed treatment, good to excellent results can be expected in 90% of such injuries.⁸

Nonsurgical treatment can also be considered in patients who either refuse surgery or are too infirm to tolerate a surgical procedure. In these patients, a functional brace or well-molded spica splint can be applied, but full recovery and complete healing of the UCL cannot be expected if the tear is complete. Some reports in the literature support the use of functional bracing and early ROM exercises in these patients, as well as in those with Stener lesions or complete tears.^{7, 8} Such reports suggest that patients recover equally well with a functional brace and daily ROM therapy regardless of the completeness of the UCL tears. However, poor UCL healing in the presence of a Stener lesion is also repeatedly confirmed in the literature.^{4, 8}

Medications that decrease acute swelling and allow better follow-up examination should be administered in the acute phase. Nonsteroidal anti-inflammatory drugs (NSAIDs), which decrease pain and swelling, are the drugs of choice.

Surgical therapy

Complete UCL tears require surgical intervention. Some reports in the literature suggest that immobilization with a special brace designed to resist the ulnar and radial deviation of the thumb may be as beneficial as surgery in patients with these injuries.⁸ However, confirmations of these suggestions are limited.

Preoperative details

Determine whether the UCL tear is partial or complete before surgical repair. Also, determine whether the UCL tear is chronic or acute, because the procedure may be different if the UCL tear is chronic.

Radiographs should be available for assessing the presence of a fracture or subluxation of the MCP joint. If the fracture fragment is large and/or displaced or if it represents more than 10% of the articular surface, fixation is required. Small displaced avulsion fractures may be excised.

Intraoperative details

Make an incision over the ulnar border of the MCP joint of the thumb. Incise the adductor aponeurosis longitudinally, and retract it distally. Then expose the dorsal capsule, and assess the proper and accessory collateral ligaments. During the surgical dissection, take care to identify and protect the sensory branch of the radial nerve; it is commonly seen within the surgical field. Even with careful dissection and retraction, postoperative radial nerve neurapraxia can still occur.

If the joint is subluxed and if the soft-tissue repair seems insufficient to hold the reduced joint, a small-gauge Kirschner wire (ie, K-wire) can be inserted to maintain the MCP joint in position. The UCL can then be repaired. In a fresh injury, the torn ends of the UCL can be directly repaired. If this approach is not possible, other techniques include attachment of the ligament to the periosteum, its reattachment to the bone by using a pull-out wire, or its fixation via the periosteum and bone flap. After the UCL is repaired, reattach the adductor aponeurosis. If a small piece of avulsed bone is present, remove it; a large bone fragment should be reduced and preserved.

For chronic UCL tears older than 6 weeks, consider repairs using the capsuloligamentous structures on the ulnar border of the MCP joint. If no degenerative changes are present at the MCP joint, consider ligament reconstruction. A free tendon, usually the palmaris longus, can be woven through the metacarpal neck and the base of the proximal phalanx. If arthritis is present or if the patient is a manual laborer, consider an arthrodesis of the MCP joint. Arthrodesis does not lead to significant impairment if the motion of the IP and carpometacarpal (CMC) joints is maintained.

Postoperative details

Postoperatively, place the patient's thumb in a spica splint, and begin carefully monitored ROM exercises of the IP and MCP joints. Alternatively, total cast immobilization for 4 weeks can be used; at 4 weeks after surgery, a removable thumb spica cast can be fabricated, and light activities of daily living (ADLs) can be initiated. The brace should be removed only for performing exercises and for hygiene. At 3 months after surgery, the patient's full activities can be resumed.

Follow-up

After 4 weeks, the thumb spica splint and any pins that were placed may be removed. A hand-based splint that immobilizes the MCP joint is then applied for 2 weeks. The splint is removed for therapy during this 2-week period, and active motion of the MCP joint is begun. Unrestricted usage is begun at 3 months.

COMPLICATIONS

Section 8 of 12  

• Authors and Editors
• Introduction
• Indications
• Relevant Anatomy
• Contraindications
• Workup
• Treatment
• Complications
• Outcome and Prognosis
• Future and Controversies
• Multimedia
• References

Chronic instability is a complication of UCL rupture. The common cause is the patient's failure to seek medical attention for diagnosis and treatment in a timely fashion. The longer a complete UCL rupture exists, the more likely it is to progress to chronic instability, even after its repair. Success in repairing the tissues after 6 weeks has been limited. The dorsal capsule, as well as the extensor pollicis brevis and extensor pollicis longus muscles, becomes attenuated, adding to the dorsal instability of the MCP joint. The thumb then tends to become displaced volarly and to rotate into a supinated position.

Chronic instability of the MCP joint can occur despite a good repair, especially if motion and return to play are resumed prematurely. This instability is difficult to treat and can lead to arthritic changes in the MCP joint, as well as a weak pinch grasp in the long term.

Stiffness of the MCP and IP joints is a common complication. This stiffness is usually not a functional problem, and it tends to improve with time.

Neuropraxia of the radial sensory nerve may occur, even if care is taken to isolate and protect the nerve during surgical repair. The neuropraxia usually resolves spontaneously.

OUTCOME AND PROGNOSIS

Section 9 of 12  

• Authors and Editors
• Introduction
• Indications
• Relevant Anatomy
• Contraindications
• Workup
• Treatment
• Complications
• Outcome and Prognosis
• Future and Controversies
• Multimedia
• References

Early diagnosis is the most important factor that determines the functional outcome in cases of gamekeeper's thumb. In thumbs with partial ligament injuries, nonsurgical treatment by means of immobilization yields a stable, painless thumb with nearly normal motion in most cases. In more than 90% of complete ruptures that are surgically treated within 3 weeks of the injury, a good to excellent result can be expected. Repair within 1 week of the injury is optimal.

Pain and stiffness can be expected to be mild or absent, and pinch and grip strength will be nearly normal. The rate of return to former activities, including recreational sports, is reported to be as high as 96%.

The failure to diagnose this injury and the patient's failure to seek medical treatment are the most common reasons for a poor outcome.

In complete tears, the failure rate of treatment with bracing and early motion is 50%. If a patient is unable to tolerate or refuses surgery, the use of a brace or thumb spica splint is the treatment of choice. However, full stability of the thumb is unlikely.

The prognosis for all repairs and reconstructions that are undertaken longer than 6 weeks after a complete UCL rupture is poor.

FUTURE AND CONTROVERSIES

Section 10 of 12  

• Authors and Editors
• Introduction
• Indications
• Relevant Anatomy
• Contraindications
• Workup
• Treatment
• Complications
• Outcome and Prognosis
• Future and Controversies
• Multimedia
• References

The future management of gamekeeper's thumb injuries is targeted at preventing the injury and improving the outcome of reconstruction in chronic complete UCL ruptures.

Ski gloves are being designed to help prevent UCL tears that are caused by a fall onto a hand holding a ski pole. As yet, these gloves are not commercially available, and they have not been proven to be beneficial.

Multiple procedures have been attempted in efforts to improve the outcome for chronic UCL ruptures. As yet, no procedure has been as effective as direct repair of the acutely ruptured UCL. Arthrodesis of the MCP joint is still the standard salvage procedure in chronic gamekeeper's thumb injuries.

MULTIMEDIA

Section 11 of 12  

• Authors and Editors
• Introduction
• Indications
• Relevant Anatomy
• Contraindications
• Workup
• Treatment
• Complications
• Outcome and Prognosis
• Future and Controversies
• Multimedia
• References

Media file 1:  Anteroposterior radiograph displaying a gamekeeper's fracture.
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Media file 2:  Lateral radiograph displaying a gamekeeper's fracture.
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Media file 3:  Radiograph displaying a stress test of a torn ulnar collateral ligament.
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Media type:  X-RAY

Media file 4:  Stress testing of the metacarpophalangeal joint of the thumb in flexion.
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Media type:  Photo

Media file 5:  Stress testing of the metacarpophalangeal joint of the thumb in extension.
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Media type:  Photo

Media file 6:  Anterior view of a hand in a thumb spica splint.
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Media file 7:  Lateral view of a hand in a thumb spica splint.
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Media type:  Photo

REFERENCES

Section 12 of 12

• Authors and Editors
• Introduction
• Indications
• Relevant Anatomy
• Contraindications
• Workup
• Treatment
• Complications
• Outcome and Prognosis
• Future and Controversies
• Multimedia
• References

1. Campbell CS. Gamekeeper's thumb. J Bone Joint Surg Br. Feb 1955;37-B(1):148-9. [Medline]. [Full Text].
2. Newland CC. Gamekeeper's thumb. Orthop Clin North Am. Jan 1992;23(1):41-8. [Medline].
3. Bekler H, Gokce A, Beyzadeoglu T. Avulsion fractures from the base of phalanges of the fingers. Tech Hand Up Extrem Surg. Sep 2006;10(3):157-61. [Medline].
4. Heyman P. Injuries to the ulnar collateral ligament of the thumb metacarpophalangeal joint. J Am Acad Orthop Surg. Jul 1997;5(4):224-9. [Medline].
5. Baskies MA, Tuckman D, Paksima N, Posner MA. A new technique for reconstruction of the ulnar collateral ligament of the thumb. Am J Sports Med. Aug 2007;35(8):1321-5. [Medline].
6. Maheshwari R, Sharma H, Duncan RD. Metacarpophalangeal joint dislocation of the thumb in children. J Bone Joint Surg Br. Feb 2007;89(2):227-9. [Medline].
7. Sollerman C, Abrahamsson SO, Lundborg G, Adalbert K. Functional splinting versus plaster cast for ruptures of the ulnar collateral ligament of the thumb. A prospective randomized study of 63 cases. Acta Orthop Scand. Dec 1991;62(6):524-6. [Medline].
8. Pichora DR, McMurtry RY, Bell MJ. Gamekeepers thumb: a prospective study of functional bracing. J Hand Surg [Am]. May 1989;14(3):567-73. [Medline].
9. Abrahamsson SO, Sollerman C, Lundborg G, Larsson J, Egund N. Diagnosis of displaced ulnar collateral ligament of the metacarpophalangeal joint of the thumb. J Hand Surg [Am]. May 1990;15(3):457-60. [Medline].
10. Gerber C, Senn E, Matter P. Skier's thumb. Surgical treatment of recent injuries to the ulnar collateral ligament of the thumb's metacarpophalangeal joint. Am J Sports Med. May-Jun 1981;9(3):171-7. [Medline].
11. Peterson JJ, Bancroft LW. Injuries of the fingers and thumb in the athlete. Clin Sports Med. Jul 2006;25(3):527-42, vii-viii. [Medline].
12. Shinohara T, Horii E, Majima M, et al. Sonographic diagnosis of acute injuries of the ulnar collateral ligament of the metacarpophalangeal joint of the thumb. J Clin Ultrasound. Feb 2007;35(2):73-7. [Medline].
13. Stener B. Displacement of the ruptured ulnar collateral ligament of the metacarpo-phalangeal joint of the thumb. J Bone Joint Surg [Br]. July 1962;44:869-79. [Full Text].

Article Last Updated: Nov 2, 2007