Gamekeeper's thumb
Encyclopedia
Gamekeeper's thumb is a type of injury to the ulnar collateral ligament
Ulnar collateral ligament (thumb)
The ulnar collateral ligament of the thumb runs along the ulnar side of the metacarpo-phalangeal joint of the thumb.It is on the radial side of the wrist, but on the ulnar side of the thumb. It should not be confused with the ulnar collateral ligament of wrist joint.-Clinical significance:Injuries...

 (UCL) of the thumb
Thumb
The thumb is the first digit of the hand. When a person is standing in the medical anatomical position , the thumb is the lateral-most digit...

. The UCL is torn at (or in some cases even avulsed from) its insertion site into the proximal phalanx
Phalanx bones
In anatomy, phalanx bones are those that form the fingers and toes. In primates such as humans and monkeys, the thumb and big toe have two phalanges, while the other fingers and toes consist of three. Phalanges are classified as long bones.The phalanges do not have individual names...

 of the thumb in the vast majority (approximately 90%) of cases. This condition is commonly observed among gamekeeper
Gamekeeper
A gamekeeper is a person who manages an area of countryside to make sure there is enough game for shooting, or fish for angling, and who actively manages areas of woodland, moorland, waterway or farmland for the benefit of game birds, deer, fish and wildlife in general.Typically, a gamekeeper is...

s and Scottish
Scottish people
The Scottish people , or Scots, are a nation and ethnic group native to Scotland. Historically they emerged from an amalgamation of the Picts and Gaels, incorporating neighbouring Britons to the south as well as invading Germanic peoples such as the Anglo-Saxons and the Norse.In modern use,...

 fowl
Fowl
Fowl is a word for birds in general but usually refers to birds belonging to one of two biological orders, namely the gamefowl or landfowl and the waterfowl...

 hunters, as well as athletes. It also occurs among ordinary people who sustain a fall onto an outstretched hand.

Symptoms and signs

Symptom
Symptom
A symptom is a departure from normal function or feeling which is noticed by a patient, indicating the presence of disease or abnormality...

s 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 are 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
Medical sign
A medical sign is an objective indication of some medical fact or characteristic that may be detected by a physician during a physical examination of a patient....

 include pain, swelling, and ecchymosis
Ecchymosis
An ecchymosis is the medical term for a subcutaneous purpura larger than 1 centimeter or a hematoma, commonly called a bruise. It can be located in the skin or in a mucous membrane.-Presentation:...

 around the thenar eminence
Thenar eminence
The thenar eminence refers to the group of muscles on the palm of the human hand at the base of the thumb...

, 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 ulnar collateral ligament
Ligament
In anatomy, the term ligament is used to denote any of three types of structures. Most commonly, it refers to fibrous tissue that connects bones to other bones and is also known as articular ligament, articular larua, fibrous ligament, or true ligament.Ligament can also refer to:* Peritoneal...

 (UCL) of the thumb. The chief difference between these two conditions is that Skier's thumb is generally considered to be an acute
Acute (medicine)
In medicine, an acute disease is a disease with either or both of:# a rapid onset, as in acute infection# a short course ....

 condition acquired after a fall or similar abduction injury to the metacarpophalangeal
Metacarpophalangeal joint
The metacarpophalangeal joints are of the condyloid kind, formed by the reception of the rounded heads of the metacarpal bones into shallow cavities on the proximal ends of the first phalanges, with the exception of that of the thumb, which presents more of the characters of a ginglymoid joint...

 (MCP) joint of the thumb, whereas gamekeeper's thumb typically refers to a chronic
Chronic (medicine)
A chronic disease is a disease or other human health condition that is persistent or long-lasting in nature. The term chronic is usually applied when the course of the disease lasts for more than three months. Common chronic diseases include asthma, cancer, diabetes and HIV/AIDS.In medicine, the...

 condition which has developed as a result of repeated episodes of lower-grade hyperabduction over a period of time. Gamekeeper's thumb is more difficult to treat because the UCL has lengthened and become thinner as a result of repeated injury.

In addition to skiing
Skiing
Skiing is a recreational activity using skis as equipment for traveling over snow. Skis are used in conjunction with boots that connect to the ski with use of a binding....

, this injury (resulting from forced abduction or hyperextension
Extension (kinesiology)
In kinesiology, extension is a movement of a joint that results in increased angle between two bones or body surfaces at a joint. Extension usually results in straightening of the bones or body surfaces involved. For example, extension is produced by extending the flexed elbow. Straightening of...

 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
Sprain
A sprain is an injury in a joint, caused by the ligament being stretched beyond its capacity. A muscular tear caused in the same manner is referred to as a strain. In cases where either ligament or muscle tissue is torn, immobilization and surgical repair may be necessary...

 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
Aponeurosis
Aponeuroses are layers of flat broad tendons. They have a shiny, whitish-silvery color, are histologically similar to tendons, and are very sparingly supplied with blood vessels and nerves. When dissected, aponeuroses are papery, and peel off by sections...

 of the adductor pollicis muscle
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....

 may be interposed between the bones of the MCP joint and the torn ligament. When this condition (referred to as a Stener lesion
Stener lesion
A Stener lesion is a type of traumatic injury to the thumb. It occurs when the aponeurosis of the adductor pollicis muscle becomes interposed between the ruptured ulnar collateral ligament of the thumb and its site of insertion at the base of the proximal phalanx...

) 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
Spica splint
A spica splint is a type of orthopedic splint used to immobilize the thumb and/or wrist while allowing other digits freedom to move. It is used to provide support for thumb injuries , gamekeeper's thumb, osteoarthritis, de Quervain's syndrome, scaphoid fracture, thumb sprains, post-operative use,...

 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
Abduction (kinesiology)
Abduction, in functional anatomy, is a movement which draws a limb away from the median plane of the body. It is thus opposed to adduction.-Upper limb:* of arm at shoulder ** Supraspinatus** Deltoid* of hand at wrist...

 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 pole
Ski poles are used by skiers to improve balance and timing. Early ski poles were simply sticks, then bamboo , then steel . In 1958, Ed Scott invented the aluminium ski pole...

, tearing the UCL by hyperabducting
Abduction (kinesiology)
Abduction, in functional anatomy, is a movement which draws a limb away from the median plane of the body. It is thus opposed to adduction.-Upper limb:* of arm at shoulder ** Supraspinatus** Deltoid* of hand at wrist...

it.

External links

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