Gamekeeper Thumb 

Updated: Apr 18, 2016
Author: Michael A Secko, IV, MD; Chief Editor: Trevor John Mills, MD, MPH 

Overview

Background

Gamekeeper's thumb was originally described by Campbell in 1955 when he reported chronic laxity of the ulnar collateral ligament (UCL) of the thumb in 24 Scottish gamekeepers. The injury occurred as gamekeepers sacrificed wounded rabbits and other small game by breaking their necks between the ground and their thumbs and index fingers.

Today, this injury is more a result of delayed treatment of an acute injury. The alternative term skier's thumb was popularized by Gerber et al and has become more synonymous with an acute injury. A significant proportion of these injuries are a result of fall or blows to the thumbs. One of the common mechanisms is a skier landing against the ski pole or ground while the thumb is abducted causing a valgus force on the thumb.

Gamekeeper’s thumb, or skier’s thumb, may constitute up to 50% of hand injuries in skiers. It may also be seen in patients with rheumatoid arthritis, those who have been in a motor vehicle accident, and athletes of other sports with injuries resulting from a fall onto an outstretched hand with an abducted thumb. MRI can establish the integrity of the ulnar collateral ligament. MRI can also distinguish between a Stener lesion and a nondisplaced or minimally retracted tear. Ultrasonography is also considered safe and accurate.[1]

Complete UCL tears require surgical intervention. Gamekeeper's fractures are usually treated conservatively, but those involving more than 30% of the joint surface and those that are malrotated or displaced should not be manipulated. Those fractures are indications for surgical intervention.[1]

Pathophysiology

The metacarpophalangeal (MCP) joint is a diarthrodial joint with the metacarpal head stabilized by ligamentous and musculotendinous attachments. The thumb MCP joint is capable of motion predominately in flexion and extension with a limited degree of rotation. The ulnar collateral ligament provides static stabilization of the thumb MCP joint. The UCL consists of both a proper ligament and an accessory ligament. The proper is taut in flexion, while the accessory is taut in extension.

The dynamic stabilizers are the intrinsic and extrinsic muscles of the thumb or most notably the adductor pollicis muscle. Dorsally, this muscle expands to form the adductor aponeurosis lying superficial to the UCL.

Chronic laxity of the UCL results from repetitive lateral stress applied to the abducted MCP joint, in particular, the stabilizing ligaments on the ulnar side of the thumb MCP joint. Subsequent instability of the first MCP joint can result from the chronic laxity of the UCL and moreover, lead to functional disability such as weakness of pincer grasp and arthritis.

An acute injury results from a sudden forced abduction stress at the MCP, particularly a fall against a ski pole or the ground. The distal attachment on the proximal phalanx is the most frequent site of rupture. The UCL may even avulse a small portion of the proximal phalanx at its insertion site. The rate of associated fractures in the skeletally mature varies from 23-50% of patients treated operatively.

A Stener lesion occurs when the ruptured end of the UCL retracts and becomes abnormally displaced proximal to the adductor aponeurosis and may be palpated clinically on the ulnar side of the MCP joint. Proper anatomical alignment and healing becomes impeded because the adductor aponeurosis becomes interposed between the sites of insertion on the proximal phalanx with the ruptured end. This lesion can also be associated with a fracture as well.

In the pediatric population, epiphyseal fusion of the proximal phalanx occurs in those aged 16-18 years. Ulnar collateral ligament ruptures of the thumb MCP joint in children are usually associated with epiphyseal fractures (Salter-Harris III) of the proximal phalanx.

Epidemiology

Frequency

United States

The incidence is increased in skiers. This common injury can also be sustained while playing football or rugby. Some instances of skier's thumb injuries are reported in sports with direct ball-to-thumb impact, such as volleyball. Gripped object sports cannot be implicated as the lone risk factor since thumb injuries are not common in sports such as lacrosse, hockey, or tennis. Ulnar collateral injuries have been reported in cases of people falling on outstretched hands with the thumb without reports of gripping any handle.

Skier's thumb is the most common upper extremity injury in skiing and is second only to medial collateral ligament (MCL) injury of the knee. Reported injury rates in downhill skiing vary between 2.3 and 4.4 per 1000 skiing days. Of these, between 7% and 9.5% are injuries to the UCL.

The incidence of Stener lesion–diagnosed definitively during surgery—was first noted in 64% of patients with clinical UCL injuries. Subsequent studies report between 14% and 87% of patients.

Mortality/Morbidity

Disruption of the UCL leads to instability of the first MCP joint. This results in poor pincer grasp and opposition and can ultimately lead to degenerative arthritic changes and difficulty carrying on the activities of daily living secondary to chronic pain.

If the diagnosis is missed or the injury is not treated properly, enduring pain, weak pincer grasp, or arthritis may result.

 

Presentation

History

Patients may complain of pain, swelling, and/or ecchymosis of the MCP joint after a fall or blow to the thumb, forcing it into a combination of hyperextension and radial (lateral) deviation. This commonly occurs while participating in sports but has been noted in patients who fall on outstretched hands and in motor vehicle accidents. The most common mechanism is a fall while holding onto a ski pole. This injury can also be seen in a football player forcibly abducting and hyperextending a thumb while holding back a rushing opponent.

Patients may also complain of weakness or worsening pain when pinching the thumb against the index finger when no acute injury is reported.

Physical

The injured thumb should be evaluated for pain, point tenderness, ecchymosis, and/or swelling, specifically on the ulnar aspect of the MCP joint.

A palpable mass on the ulnar aspect of the MCP joint may be obvious and may represent the ruptured UCL that is abnormally displaced proximally and dorsally relative to the adductor aponeurosis.

Standard radiographs should be obtained before lateral stress examination, because stress testing may cause further displacement of an avulsion fracture that was originally minimally displaced.

Valgus (lateral) stress testing can determine the integrity of the UCL. Stability of the opposite thumb should be tested as well for comparison.

Stress examination is performed while stabilizing the thumb metacarpal with one hand to prevent rotation. The thumb should be placed in 30° flexion, and a lateral (radial) stress should be applied on the joint.

A displaced avulsion fracture is a contraindication to stress testing but a nondisplaced fracture is not.

Administration of local anesthetic may be necessary to facilitate optimal examination. This can be accomplished by either a local injection of 1% lidocaine into the MCP joint or by blocking the sensory branches of the radial and median nerves at the wrist.

Laxity (angulation) of more than 35° or laxity 15° more than the uninjured side suggests a complete rupture of the proper collateral ligament. Laxity (angulation) less than 35° or comparative laxity less than 15° probably denotes an incomplete rupture.

The accessory collateral ligament may remain intact, and gross instability may not be present. Therefore, examination in extension should be performed. Reports have demonstrated that laxity of the MCP joint in extension when stressed, consistently indicates tears of the proper and accessory collateral ligaments and is more commonly associated with a Stener lesion. Laxity of more than 35° or laxity of 15° more than the uninjured side may suggest rupture of the accessory collateral ligament.

If lateral (valgus) laxity of the MCP joint exists for both the flexed and extended positions, then complete rupture of the UCL should be suspected, and greater possibility of a Stener lesion exists.

Causes

Fall onto outstretched hand causing a forced abduction and extension of the thumb

 

DDx

Differential Diagnoses

 

Workup

Laboratory Studies

No laboratory tests are necessary for making the diagnosis. Routine preoperative laboratory workup may be required for those cases requiring surgical intervention.

Imaging Studies

Standard radiographs

Posteroanterior (PA), lateral, and possibly oblique radiographs of the thumb are indicated in patients with a suspected gamekeeper's thumb to identify any avulsion fracture at the base of the proximal phalanx.

Findings on plain films are usually normal in the absence of an avulsion fracture. Degenerative joint changes may be seen years later after the initial insult or with chronic injury.

Displaced avulsion fractures or any fracture involving 25% or more of the MCP joint surface requires surgical treatment and should not be manipulated.

Anteroposterior (AP) view: The presence of an avulsion fracture at the base of the proximal phalanx, or less frequently, at the metacarpal head, is suggestive of ligamentous rupture. The persistence of a radially subluxed MCP joint suggests an interposed rupture of the UCL.

Lateral view (see image below): A volar subluxation of the MCP joint suggests a tear involving the dorsal capsule and the volar plate indicating probable UCL rupture and instability.

Lateral radiograph displaying a gamekeeper's fract Lateral radiograph displaying a gamekeeper's fracture.

Stress radiographs (+/- local anesthesia)

If the diagnosis of gamekeeper thumb is suspected and radiographs show no fracture, comparative radiographs should be obtained in forced valgus. Administration of local anesthesia may be required for proper manipulation. The forced valgus maneuver, which uses a stress test to cause joint tilt, is crucial in making an accurate diagnosis and deciding on the most appropriate therapeutic approach. Researchers report on a method that allows the patient’s thumbs to be compared, under the same force application conditions, on a single radiograph, thereby reducing the patient’s and the examiner’s exposure to x-rays. According to the authors, the technique is well tolerated by the patient and anesthesia for the thumb is usually not necessary.[2]

Radiographs of the MCP join in flexion; extension and lateral stress are useful in grading the severity of MCP joint instability, especially of partial tears of the UCL. As mentioned earlier, greater than 35° of angulation suggests a complete tear.

Other imaging modalities

Arthrography may visualize Stener lesions, but it is an invasive technique, and results are difficult to interpret.

MRI or MR arthrography may be helpful in cases of suspected gamekeeper's thumb by accurately depicting the osseous and soft tissue structures about the MCP joint, including the UCL and surrounding ligaments and tendons.[3] MRI may be impractical and cost prohibitive.

In patients treated surgically, MR imaging resulted in identifying UCL tears with 96% sensitivity and 95% specificity.[4]

Ultrasonography has been shown to be highly accurate in diagnosing Stener lesions.[5] In a study of patients treated surgically, ultrasonography had a sensitivity of 83%, specificity 75%, and a positive predictive value of 94%.[6]

For the emergency physician, carrying out these highly specific tests may not be practical. Standard radiographs and adequate physical examination should be enough to determine those cases that necessitate surgical repair.

 

Treatment

Prehospital Care

Ice should be applied acutely. Splinting may avoid painful motion associated with travel to the hospital.

Emergency Department Care

Gamekeeper's thumb injuries may or may not require surgical intervention. This decision is typically made by an appropriate specialist such as a hand/orthopedic surgeon. The emergency medicine physician should immobilize all suspected injuries in a thumb spica splint and have the patient follow up within 1 week.

Injuries that are not fixed surgically require application of a well-molded functional brace (short arm thumb spica or a smaller, glove-type thumb spica) for 4-6 weeks, with the MCP joint typically flexed to about 20-30°. These include the following:

  • Partial tears of the UCL

  • Nondisplaced avulsion fractures

Gamekeeper's thumb injuries that require surgical exploration to identify a Stener lesion and restore proper anatomical alignment include the following:

  • Complete tears

  • Displaced avulsion fractures

  • Large (>25%) articular surface fracture of the proximal phalanx

  • Volar subluxation of the proximal phalanx

Classification, examination, and treatment of skier's thumb (adapted from Hinterman et al[7] )

  • Type I: Nondisplaced fracture, stable in flexion (< 35° angulation); conservative management with 4-6 weeks in plaster cast (short arm thumb spica, or small glove-type thumb spica cast)

  • Type II: Displaced fracture; treat surgically

  • Type III: No fracture, stable in flexion (< 35° angulation); conservative management in cast for 4-6 weeks

  • Type IV: No fracture, unstable in flexion (>35° angulation); treat surgically

  • Type V: Avulsion fracture of volar plate, stable in flexion; conservative management in cast for 4-6 weeks

  • Type VI: Fragmentation of volar ulnar portion of proximal phalanx with associated injury of the UCL; treat surgically

In regards to all the different types of surgical repairs, success rates are comparable with all of the most commonly used operative techniques.

  • Pediatric gamekeeper's thumb: If fragment (Salter-Harris III) is displaced by less than 2 mm, nonsurgical management is indicated. For fragments displaced greater than 2 mm, surgery is the best option. Salter-Harris type I and II fractures associated with UCL instability may heal well with casting alone.

In an evaluation of 43 cases of UCL injury by MRI to measure the degree of ligament displacement, it was found that partial and minimally displaced UCL tears and tears displaced less than 3 mm typically healed by immobilization alone. For tears displaced more than 3 mm, immobilization failed in 90% of cases and required surgery, along with all cases with a Stener lesion.[3]

Consultations

An orthopedic or hand surgeon should be notified if the injury requires operative management to ensure timely repair.

 

Medication

Medication Summary

Nonsteroidal anti-inflammatory (NSAIDs) that reduce pain and swelling are the treatment of choice.

A brief course of narcotics may be warranted to alleviate the acute phase of pain and swelling.

Analgesics

Class Summary

Pain control is essential to quality patient care. Analgesics ensure patient comfort, promote pulmonary toilet, and have sedating properties, which are beneficial for patients who have sustained trauma or injuries.

Ibuprofen (Ibuprin, Advil, Motrin)

Usually DOC for treatment of mild to moderate pain, if no contraindications exist. Inhibits inflammatory reactions and pain probably by decreasing the activity of the enzyme cyclooxygenase, which results in prostaglandin synthesis.

Acetaminophen (Tylenol, Panadol, Aspirin-free Anacin)

DOC for treating mild pain in patients with documented hypersensitivity to aspirin or NSAIDs, those with upper GI disease, or who take oral anticoagulants.

Naproxen (Anaprox, Naprelan, Naprosyn)

Used for relief of mild to moderate pain. Inhibits inflammatory reactions and pain by decreasing activity of the enzyme cyclooxygenase, which results in prostaglandin synthesis.

Ketoprofen (Oruvail, Orudis, Actron)

Used to relieve mild to moderate pain and inflammation. Initially administer small dosages to patients with a small body size, elderly patients, and those with renal or liver disease. Doses higher than 75 mg do not increase therapeutic effects. Administer high doses with caution, and closely observe patients for response.

Acetaminophen and codeine (Tylenol #3)

Drug combination indicated for treatment of mild to moderate pain.

Oxycodone and acetaminophen (Percocet, Roxicet, Tylox)

Drug combination indicated to relieve moderate to severe pain; DOC for aspirin-hypersensitive patients.

Hydrocodone bitartrate and acetaminophen (Vicodin)

Drug combination indicated to relieve moderate to severe pain.

 

Follow-up

Further Outpatient Care

Conservative management with a functional brace

Once the cast or splint has been removed, a period of active MCP flexion exercises should be followed with gradual return to activities.

Patients should be advised to avoid heavy gripping or grasping until the grip strength has returned to normal.

Surgical management

Patients should be placed in a short arm thumb spica cast for 4 weeks.

The thumb spica cast and pins (if any were placed) are removed after 4 weeks.

For the ensuing 2 weeks, a splint that immobilizes the MCP is applied and removed for therapy of the MCP.

Next is active range of motion of the MCP joint and unrestricted usage is allowed at about 3 months postoperatively.

Follow-up care should be arranged with an orthopedic or a hand surgeon.

Surgery may be necessary in patients who do not respond to conservative therapy initially.

Inpatient & Outpatient Medications

A course of NSAIDs is recommended.

A brief course of narcotics may be needed to alleviate the acute phase of pain and swelling.

Complications

Chronic instability is a major complication of UCL rupture. An unstable MCP joint can lead to degenerative joint changes and cause weakness of power grasp as well as decreased dexterity of fine pincher-type movements.

The most common cause is failure to seek medical attention in a timely fashion or a missed diagnosis.

Risk factors for chronic instability include the following:

  • Larger tears

  • Those left untreated or have delayed treatment more than 6 weeks

  • Return to play/activities too prematurely

  • May even occur after adequate repair

Stiffness of the metacarpal and interphalangeal joint may be seen, especially following cast removal. Most improve with time and range of motion exercises.

Transient neurapraxia of the branch of the superficial radial nerve may be a complication after undergoing surgery.

Prognosis

Most authors agree that early diagnosis is the most important factor that determines the functional outcome.

Partial ligament tears

Nonsurgical conservative management usually yields thumbs with normal range of motion.

Complete ligament tears

Early referral/consultation is indicated, especially if some degree of uncertainty exists about whether a complete UCL tear is present.

The failure rate is about 50% using conservative treatment with functional bracing and early motion exercises.

Early surgical intervention—within 3 weeks of injury—has led to good results in the treatment of gamekeeper's/skier's thumb injury. The prognosis may be worse if surgical intervention has been delayed. The anatomy may be too distorted by 6 weeks to permit direct repair; however, studies have reported good results obtainable with late repair or reconstruction.

Patient Education

Changes in pole design, such as the strapless pole, have not been associated with a decrease in the incidence of gamekeeper's/skier's thumb injuries. If skiers are trained to discard their pole or poles during a fall, the risk might be reduced.