Orthopedic Surgery for Gamekeeper's Thumb 

Updated: Oct 08, 2020
Author: Matthew Hannibal, MD; Chief Editor: Harris Gellman, MD 

Overview

Practice Essentials

Gamekeeper's thumb is a clinical instability of the first metacarpophalangeal (MCP) joint caused by an insufficiency of the ulnar collateral ligament (UCL) in the MCP joint of the thumb.[1]  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.[2, 3, 4, 5, 6]

The common name for this condition, originally coined in 1955,[7]  derived from the observation that this injury was most often associated with Scottish gamekeepers, especially rabbit keepers. In these individuals, the injury was work-related, occurring as game animals (eg, rabbits) were sacrificed. The animals' necks were broken between the ground and the gamekeeper's thumb and index fingers; this placed a valgus force onto the abducted MCP joint, leading to UCL injury and to instability accompanied by pain and weakness of the pinch grasp.

Currently, 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.[8]  The alternative term skier's thumb reflects the acute nature of the injury.[9, 10, 11, 12, 13, 14]  The injury has also been found to occur in ice hockey players.[15]

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. Complete UCL tears necessitate surgical intervention. It is important to determine whether the UCL tear is chronic or acute; the procedure may be different if the tear is chronic. Nonsurgical treatment can also be considered in patients who either refuse surgery or are too infirm to tolerate a surgical procedure. 

Anatomy

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 × 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.

Pathophysiology

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 fracture[9] ; this injury can be subtle or obvious, 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.

Etiology

Gamekeeper's thumb is caused by a valgus force that is directed on the MCP joint of the thumb 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. (For a discussion of the anatomy of the MCP joint and the UCL, see Anatomy.)

Chuter et al, over a 10-year period, studied 127 patients who underwent surgical repair of an acute thumb UCL rupture for clinically unstable injuries or displaced avulsion fractures.[5] Most of the injuries (≥66%) were hyperextension or abduction injuries. The most common cause was a fall (49%), followed by sports injuries (skiing injuries accounted for only 2.4% of injuries). More than 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%).

Epidemiology

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.

Prognosis

Failure of the physician to diagnose this injury and failure of the patient to seek medical treatment are the most common reasons for a poor outcome.

Early diagnosis is the most important determinant of functional outcome in cases of gamekeeper's thumb. 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. The prognosis for all repairs and reconstructions that are undertaken longer than 6 weeks after a complete UCL rupture is poor.

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 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.

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%.

 

Presentation

Physical Examination

The injured thumb should be evaluated for swelling and pain at the ulnar aspect of the metacarpophalangeal (MCP) joint. Ecchymosis is frequently seen. A palpable mass on the ulnar aspect of the MCP joint may represent the retracted ulnar collateral ligament (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 for 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).[16, 10]  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 collateral ligament and the accessory collateral ligament 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.[16, 10]  If valgus laxity of the MCP joint is present in both the flexed and extended positions, complete UCL rupture should be suspected.

 

Workup

Laboratory Studies

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

Imaging Studies

Standard radiography

Before any manipulation of the thumb, obtain standard anteroposterior (AP), lateral, and oblique radiographs to exclude metacarpal fractures and gamekeeper's fractures (see the images below).

Anteroposterior radiograph displaying gamekeeper's Anteroposterior radiograph displaying gamekeeper's fracture.
Lateral radiograph displaying gamekeeper's fractur Lateral radiograph displaying gamekeeper's fracture.

Nondisplaced avulsion fractures that are associated with rupture of the insertion point of the ulnar collateral ligament (UCL) are not contraindications for 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 radiography

Radiographs obtained with the thumb in the flexed and extended positions and with valgus stress at the MCP joint (see the image below) can help the physician to determine the degree of instability of partial tears of the UCL.[17]

Radiograph displaying stress test of torn ulnar co Radiograph displaying stress test of torn ulnar collateral ligament.

Ultrasonography

Ultrasonography has been found to be effective for evaluating the collateral ligaments of the MCP and IP joints and identifying injuries such as gamekeeper's thumb.[18]

In a French study, Gherissi et al evaluated echography (ultrasonography [US]) to diagnose Stener lesions in 25 gamekeeper's thumbs from March 2005 to March 2007.[2] They found that US is useful in identifying Stener lesion in the emergency department (ED) because it is available, cheap, noninvasive, and dynamic. US was ultrasonographer-dependent and ultrasonogram-dependent. The author's study revealed the advantage of using US with tissue harmonic imaging.

Magnetic resonance imaging

In a 2015 study of 43 UCL injuries, Milner et al described the use of magnetic resonance imaging (MRI) to assess the degree of UCL displacement and thereby help create a four-type classification to facilitate determination of which UCL injuries require surgical treatment.[19] They found that type 1 (partial or minimally displaced) and type 2 (< 3 mm displaced) tears typically healed by immobilization alone, whereas 90% of type 3 (>3 mm displaced) tears failed immobilization and required surgery, as did 100% of type 4 (Stener) tears.

Procedures

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 ED or in the office setting (see the images below). Often, 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.

Stress testing of metacarpophalangeal joint of thu Stress testing of metacarpophalangeal joint of thumb in flexion.
Stress testing of metacarpophalangeal joint of thu Stress testing of metacarpophalangeal joint of thumb in extension.

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

Approach Considerations

Nonsurgical treatment can be considered for partial tears of the ulnar collateral ligament (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.[11]  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.

In gamekeeper's thumb, no absolute contraindications for surgery exist. Relative surgical contraindications include the following:

  • A patient who is too infirm to tolerate surgery, regardless of whether a complete UCL tear is present
  • In a child, gamekeeper's thumb 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 metacarpophalangeal (MCP) joint has had limited success. Even surgical repair that is performed 6 weeks after the complete UCL rupture has had limited success. Essentially, the longer a complete rupture of the UCL exists, the smaller the possibility of stability restoration with anatomic repair (see Complications).

Some surgeons have reported success with dynamic transfer of a tendon (eg, 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.

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. Although multiple procedures have been attempted in efforts to improve the outcome for chronic UCL ruptures, no procedure has yet been proved to be 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.

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 the images below). 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.[20]

Anterior view of hand in thumb spica splint. Anterior view of hand in thumb spica splint.
Lateral view of hand in thumb spica splint. Lateral view of hand in thumb spica splint.

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 range-of-motion (ROM) exercises in these patients, as well as in those with Stener lesions or complete tears.[21, 20] 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.[16, 20]

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 necessitate 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.[20] However, confirmations of these suggestions are limited.

Christensen et al evaluated long-term outcomes of ligamentous repair rather than reconstruction in 12 patients with chronic thumb UCL injuries who were followed for longer than 15 years (average, 24.5 years; range, 16.9-35.6).[22] They found that repair of such injuries with available local tissue appeared to be a reasonable alternative to ligament reconstruction that yielded durable long-term outcomes despite the majority of patients (88%) progressing to osteoarthritis.

In a single-center retrospective study of 55 patients with chronic posttraumatic thumb MCP joint instability who were managed surgically and followed for a mean of 84 months, Agout et al compared three techniques—primary repair, ligament reconstruction, and arthrodesis—with respect to subjective and objective outcomes and complication rates at last follow-up.[23] They concluded that primary repair deserves preference whenever possible, and they found that outcomes after ligament reconstruction were not superior to those after arthrodesis.

Preparation for surgery

Before embarking on surgical repair, determine whether the UCL tear is partial or complete. In addition, 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 or displaced or if it represents more than 10% of the articular surface, fixation is required. Small displaced avulsion fractures may be excised.

Operative details

Make an incision over the ulnar border of the MCP joint of the thumb. Incise the adductor aponeurosis longitudinally, and retract it distally. Next, 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 (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 arthrodesis of the MCP joint. This does not lead to significant impairment if the motion of the IP and carpometacarpal (CMC) joints is maintained.

Postoperative Care

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 may 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. 

Complications

Chronic instability is a complication of UCL rupture. The common cause is 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 repair. Success in repairing the tissues after 6 weeks has been limited. The dorsal capsule, the extensor pollicis brevis, and the extensor pollicis longus become 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.

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

Prevention

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 proved to be beneficial.

Long-Term Monitoring

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, including the resumption of full ADLs, is begun at 3 months.