Gamekeeper's thumb (also known as skier's thumb or UCL tear) is a type of injury to the

ulnar collateral ligament Ulnar collateral ligament (or UCL), may refer to: * Ulnar carpal collateral ligament * Ulnar collateral ligament of elbow joint The ulnar collateral ligament (UCL) or internal lateral ligament is a thick triangular ligament at the medial aspec ...

(UCL) of the thumb. The UCL may be merely stretched, or it may be torn from its insertion site into the

proximal Standard anatomical terms of location are used to unambiguously describe the anatomy of animals, including humans. The terms, typically derived from Latin or Greek roots, describe something in its standard anatomical position. This position pro ...

phalanx The phalanx ( grc, φάλαγξ; plural phalanxes or phalanges, , ) was a rectangular mass military formation, usually composed entirely of heavy infantry armed with spears, pikes, sarissas, or similar pole weapons. The term is particularly ...

of the thumb; in approximately 90% of cases part of the bone is actually avulsed from (sheared away from) the joint. This condition is commonly observed among

gamekeeper A gamekeeper (often abbreviated to keeper), or in case of those dealing with deer (deer-)stalker, is a person who manages an area of countryside (e.g. areas of woodland, moorland, waterway or farmland) to make sure there is enough game for s ...

s and Scottish

fowl Fowl are birds belonging to one of two biological orders, namely the gamefowl or landfowl (Galliformes) and the waterfowl (Anseriformes). Anatomical and molecular similarities suggest these two groups are close evolutionary relatives; together ...

hunters, as well as athletes (such as volleyballers and soccer goalkeepers). It also occurs among people who sustain a fall onto an outstretched hand while holding a rod, frequently

skiers Skiing is the use of skis to glide on snow. Variations of purpose include basic transport, a recreational activity, or a competitive winter sport. Many types of competitive skiing events are recognized by the International Olympic Committee (IO ...

grasping ski poles.

Signs and symptoms

Symptoms of gamekeeper's thumb are instability of the MCP joint of the thumb, accompanied by pain and weakness of the pinch grasp. The severity of the symptoms is related to the extent of the initial tear of the UCL (in the case of skier's thumb), or how long the injury has been allowed to progress (in the case of gamekeeper's thumb). Characteristic signs include pain, swelling, and

ecchymosis A bruise, also known as a contusion, is a type of hematoma of tissue, the most common cause being capillaries damaged by trauma, causing localized bleeding that extravasates into the surrounding interstitial tissues. Most bruises occur close ...

around the

thenar eminence The thenar eminence is the mound formed at the base of the thumb on the palm of the hand by the intrinsic group of muscles of the thumb. The skin overlying this region is the area stimulated when trying to elicit a palmomental reflex. The word ...

, and especially over the MCP joint of the thumb. Physical examination demonstrates instability of the MCP joint of the thumb. The patient will often manifest a weakened ability to grasp objects or perform such tasks as tying shoes and tearing a piece of paper. Other complaints include intense pain experienced upon catching the thumb on an object, such as when reaching into a pants pocket.

Diagnosis

Gamekeeper's thumb and skier's thumb are two similar conditions, both of which involve insufficiency of the

ulna The ulna (''pl''. ulnae or ulnas) is a long bone found in the forearm that stretches from the elbow to the smallest finger, and when in anatomical position, is found on the medial side of the forearm. That is, the ulna is on the same side of t ...

r collateral ligament (UCL) of the thumb. The chief difference between these two conditions is that skier's thumb is generally considered to be an

acute Acute may refer to: Science and technology * Acute angle ** Acute triangle ** Acute, a leaf shape in the glossary of leaf morphology * Acute (medicine), a disease that it is of short duration and of recent onset. ** Acute toxicity, the adverse eff ...

condition acquired after a fall or similar abduction injury to the

metacarpophalangeal The metacarpophalangeal joints (MCP) are situated between the metacarpal bones and the proximal phalanges of the fingers. These joints are of the condyloid kind, formed by the reception of the rounded heads of the metacarpal bones into shallow cav ...

(MCP) joint of the thumb, whereas gamekeeper's thumb typically refers to a chronic condition which has developed as a result of repeated episodes of lower-grade hyperabduction over a period of time. There are four types of Skier's thumb injury: * Avulsion of distal UCL causing the pulling off of a bone chip off the proximal phalanx base. * Partial-thickness tear of the UCL * Full-thickness tear of the middle part of the UCL * Full-thickness tear of the middle part of the UCL with the proximal fragment displaced superficial to the aponeurosis of adductor pollicis, thus preventing the healing of proximal and distal segments of UCL. This condition is called Stener lesion. Gamekeeper's thumb is more difficult to treat because the UCL has lengthened and become thinner as a result of repeated injury. It is moderately painful compared to similar injuries. In addition to

skiing Skiing is the use of skis to glide on snow. Variations of purpose include basic transport, a recreational activity, or a competitive winter sport. Many types of competitive skiing events are recognized by the International Olympic Committee ( ...

, this injury (resulting from forced abduction or

hyperextension Motion, the process of movement, is described using specific anatomical terms. Motion includes movement of organs, joints, limbs, and specific sections of the body. The terminology used describes this motion according to its direction relativ ...

of the proximal phalanx of the thumb) is seen in a wide variety of other athletic endeavors. The most common mechanism of injury appears to be when a person extends the arm in an attempt to block a fall. The stress resulting from falling onto an abducted thumb produces a valgus force on the MCP joint of the thumb, resulting in a sprain or tear of the UCL. In a recent study, 49% of UCL disruptions of the thumb were caused by a fall onto an outstretched hand. Sports injuries accounted for most of the remaining injuries, with only 2.4% acquired as a result of skiing injuries.

Treatment

The ulnar collateral ligament is an important stabilizer of the thumb. Thumb instability resulting from disruption of the UCL profoundly impairs the overall function of the involved hand. Because of this, it is critical that these injuries receive appropriate attention and treatment. In most cases of a complete tear, the aponeurosis of the

adductor pollicis muscle In human anatomy, the adductor pollicis muscle is a muscle in the hand that functions to adduct the thumb. It has two heads: transverse and oblique. It is a fleshy, flat, triangular, and fan-shaped muscle deep in the thenar compartment beneath ...

may be interposed between the bones of the MCP joint and the torn ligament. When this condition (referred to as a Stener lesion) occurs, the adequate healing of the tear is prevented altogether. For a Stener lesion to occur, a complete tear of the ulnar collateral ligament must be present. However, the Stener lesion can occur even in the absence of a tear of the accessory collateral ligament or volar plate. The Stener lesion is present in more than 80% of complete ruptures of the UCL of the thumb. When approaching this type of injury, the physician must first determine whether there is an incomplete rupture (or sprain) of the UCL, or a complete rupture. If the UCL is completely disrupted, the physician must then determine whether there is interposition of the adductor aponeurosis (Stener lesion), or simply a complete rupture of the UCL with anatomic or near-anatomic position. Radiographs are helpful in determining the possible presence of an avulsion fracture of the proximal phalanx insertion site of the ulnar collateral ligament. Stress examination, or one done under fluoroscopic guidance, can help determine the integrity of the ligament. Most gamekeeper's thumb partial injuries are treated by simply immobilizing the joint in a thumb spica splint or a modified wrist splint and allowing the ligament to heal. However, near total or total tears of the UCL may require surgery to achieve a satisfactory repair, especially if accompanied by a Stener lesion.

History

CS Campbell, an orthopedic surgeon, originally coined the term gamekeeper's thumb in 1955, after he observed this condition in a series of 24 Scottish gamekeepers. The injury appeared to occur as a result of the particular manner in which they killed small animals such as rabbits; the animals were placed on the ground, and their necks were broken as the gamekeeper exerted downward pressure with the thumb and index finger. This maneuver would place a valgus force upon the abducted metacarpophalangeal (MCP) joint. Over time, this would lead to insufficiency of the ulnar collateral ligament (UCL) of the thumb. Others have noted that Scottish fowl or game hunters would develop this type of injury after carrying their game home in a leather thong, which they would attach to their thumb and drape over their shoulder. The term skier's thumb is derived from the fact that skiers often acquire this type of injury by falling against a planted

ski pole Ski poles, also referred to as poles (in North America), sticks (UK), or stocks (Australia), are used by skiers for balance and propulsion. Modern ski poles are most commonly made from aluminum and carbon fiber, though materials such as bamboo are ...

, tearing the UCL by hyperabducting it.

References

External links