Gamekeeper’s Thumb: Test, Radiology (X-Ray & MRI), Treatment, Brace, Splint, Exercises, and Surgery

Gamekeeper’s Thumb:

• What is Gamekeeper’s Thumb?
• Test
• Radiology (X-Ray & MRI)
• Treatment
• Brace
• Splint
• Exercises
• Surgery

What is Gamekeeper’s Thumb?

Gamekeeper’s thumb, also called ulnar collateral ligament (UCL) injury of the thumb, is a common injury affecting the ligament on the inner side of the thumb at the metacarpophalangeal (MCP) joint. It often occurs due to forceful abduction or hyperextension of the thumb, such as during a fall or sports-related accident. The name “Gamekeeper’s thumb” originates from an old term used to describe injuries among Scottish gamekeepers who used repetitive thumb motions to kill small animals.

This injury can range from mild ligament sprain to complete ligament rupture, sometimes associated with avulsion fractures of the proximal phalanx. If left untreated, it can lead to chronic instability, pain, and reduced pinch strength. Early diagnosis and appropriate management are key to restoring function and preventing long-term complications.

Test

The primary clinical test for Gamekeeper’s thumb is the valgus stress test of the MCP joint. The clinician stabilizes the thumb metacarpal and applies outward pressure to the proximal phalanx to assess ligament laxity or instability. A positive test indicates a partial or complete UCL tear.

Other assessments may include comparing the injured thumb with the uninjured thumb to determine the degree of laxity and joint instability. Tenderness, swelling, and bruising along the ulnar side of the MCP joint are commonly observed. In some cases, a Stener lesion is suspected, where the torn ligament is displaced above the adductor aponeurosis, requiring surgical intervention.

Radiology (X-Ray & MRI)

X-rays are often performed first to rule out fractures or avulsion injuries. Standard anteroposterior and lateral views of the thumb can reveal small bone fragments or joint misalignment associated with ligament injury. Stress X-rays can sometimes be used to quantify instability.

MRI is the gold standard for soft tissue evaluation, providing detailed imaging of the UCL, adductor aponeurosis, and surrounding structures. MRI can confirm partial or complete tears, detect Stener lesions, and guide treatment planning. Accurate imaging helps differentiate between injuries that can heal conservatively versus those requiring surgical repair.

Treatment

Treatment of Gamekeeper’s thumb depends on the severity of the ligament injury. Mild sprains or partial tears are typically managed conservatively with immobilization using a brace or splint. Ice, elevation, and nonsteroidal anti-inflammatory drugs (NSAIDs) can help reduce pain and swelling.

Complete tears or Stener lesions usually require surgical repair to restore thumb stability. Early intervention prevents chronic instability and loss of grip strength. Rehabilitation after immobilization or surgery is critical for regaining motion, strength, and function of the thumb.

Brace

A thumb brace provides support to the MCP joint during healing. It restricts unwanted movement while allowing some functional activity. The brace is typically worn for 4–6 weeks for mild to moderate injuries. Modern braces are adjustable, lightweight, and designed to maintain proper thumb alignment while allowing limited hand function.

Braces can be used during daily activities to prevent reinjury and protect the healing ligament. They are often combined with buddy taping or finger immobilization to enhance stability in more severe injuries. Proper fit is essential to ensure effectiveness and comfort.

Splint

Splints are rigid devices used to immobilize the thumb MCP joint completely, particularly for complete UCL tears or post-surgical care. A typical splint keeps the thumb in slight flexion and prevents abduction, allowing optimal ligament healing.

Custom or prefabricated splints are used based on injury severity. Duration of splinting ranges from 4 to 6 weeks, after which gradual mobilization and strengthening exercises are started. Splints are essential for protecting surgical repairs and preventing chronic instability.

Exercises

After immobilization, rehabilitation exercises are essential to restore thumb strength, mobility, and function. These include gentle range of motion exercises, grip strengthening, pinch exercises, and functional hand activities. Occupational or physical therapists often guide patients through progressive exercises to ensure safe recovery.

Therapy also focuses on proprioception and dexterity, especially for athletes or individuals using their hands extensively for work. Gradual strengthening prevents reinjury and helps patients regain normal hand performance, including pinch and grip tasks.

Surgery

Surgery is indicated for complete UCL tears, Stener lesions, or chronic instability. The procedure involves reattaching or reconstructing the ligament, often using sutures, anchors, or tendon grafts depending on the injury. Postoperative immobilization is required, followed by a structured rehabilitation program.

Surgical outcomes are generally excellent, with most patients regaining full thumb function and stability. Early recognition of injuries requiring surgery is essential to prevent chronic pain, loss of grip strength, and long-term functional impairment.