Gamekeeper's Thumb (UCL Injury)
Summary
Gamekeeper's thumb refers to injury of the ulnar collateral ligament (UCL) of the thumb metacarpophalangeal joint (MCPJ). The acute form ("Skier's thumb") occurs from a sudden valgus force to the thumb — commonly from a fall while holding a ski pole. The chronic form ("Gamekeeper's thumb") results from repetitive stress (historically from gamekeepers wringing the necks of game birds). A critical complication is the Stener lesion, where the torn ligament is displaced superficial to the adductor aponeurosis, blocking healing and necessitating surgical repair. Partial tears are managed conservatively with immobilisation; Complete tears or Stener lesions require surgery.
Key Facts
- Mechanism: Forced abduction (valgus force) on thumb MCPJ
- Acute (Skier's): Fall with thumb abducted (ski pole)
- Chronic (Gamekeeper's): Repetitive stress
- Stener Lesion: UCL trapped above adductor aponeurosis — Will NOT heal without surgery
- Examination: Laxity >30° on valgus stress (or >15° vs other side)
- Treatment: Splint (partial); Surgery (complete/Stener)
Clinical Pearls
"Stener = Surgery": If the UCL is displaced superficial to the adductor aponeurosis, it cannot heal without surgical repair.
"Compare Both Thumbs": Stress testing both sides is essential — >15° difference indicates significant injury.
"MRI/USS for Stener": Imaging can identify a Stener lesion and guide management.
"Common Ski Injury": Always examine UCL in a patient with thumb pain after skiing.
Incidence
- Second most common skiing injury
- Common in ball sports
Demographics
- M = F
- Peak: Young adults (sports-related)
Mechanism
| Setting | Cause |
|---|---|
| Skiing | Fall while holding pole |
| Ball sports | Catching ball with thumb abducted |
| Falls | FOOSH with thumb forced outward |
Anatomy
- UCL stabilises MCPJ against valgus stress
- Proper collateral ligament is taut in flexion
- Accessory collateral merges with volar plate
Injury Mechanism
- Forced abduction of thumb at MCPJ
- UCL tears (usually at distal insertion on proximal phalanx)
Stener Lesion
- Torn UCL retracts proximally
- Displaced superficial to adductor aponeurosis
- Aponeurosis now lies between ligament and bone
- Prevents healing without surgery
- Present in 14-83% of complete ruptures
Symptoms
| Feature | Description |
|---|---|
| Pain | Ulnar side of thumb MCPJ |
| Swelling | Ulnar aspect of thumb base |
| Weakness | Pinch grip weakness |
| Instability | Thumb "gives way" |
History
Inspection
- Swelling (ulnar side of MCPJ)
- Bruising
Palpation
- Tender over UCL (ulnar aspect of MCPJ)
- May palpate a mass (displaced UCL/Stener)
Special Tests
| Test | Technique | Positive |
|---|---|---|
| Valgus Stress (0°) | Apply radial force with MCPJ extended | >30° laxity or >5° vs other side |
| Valgus Stress (30° flexion) | Same with MCPJ flexed | Tests proper collateral |
| No endpoint | Soggy feel | Complete rupture |
Imaging
| Modality | Findings |
|---|---|
| X-ray | Avulsion fracture at proximal phalanx base |
| Ultrasound | Can identify retracted UCL and Stener lesion |
| MRI | Gold standard for diagnosing Stener lesion |
Treatment Approach
┌──────────────────────────────────────────────────────────┐
│ GAMEKEEPER'S THUMB MANAGEMENT │
├──────────────────────────────────────────────────────────┤
│ │
│ PARTIAL TEAR (STABLE): │
│ • Thumb spica cast or splint (6 weeks) │
│ • Hand therapy │
│ │
│ COMPLETE TEAR WITHOUT STENER: │
│ • Can consider conservative (splint 6 weeks) │
│ • OR Surgical repair │
│ │
│ COMPLETE TEAR WITH STENER: │
│ • SURGICAL REPAIR (essential) │
│ • Direct repair with suture anchors │
│ • Post-op: Thumb spica 4-6 weeks then therapy │
│ │
│ AVULSION FRACTURE: │
│ • Small/non-displaced: Cast │
│ • Displaced >2mm: ORIF │
│ │
│ CHRONIC INSTABILITY: │
│ • UCL reconstruction (tendon graft) │
│ │
└──────────────────────────────────────────────────────────┘
Of Injury
- Chronic instability (if untreated)
- Weak pinch grip
- Osteoarthritis of MCPJ
Of Surgery
- Stiffness
- Numbness (dorsal digital nerve)
- Persistent instability
- Infection
Partial Tears
- Excellent outcomes with splinting
Stener Lesion
- Will NOT heal without surgery
- Good outcomes with timely repair
Chronic Instability
- Requires reconstruction; More variable outcomes
Key Resources
- BSSH: British Society for Surgery of the Hand
Key Evidence
Stener Lesion
- MRI or USS recommended when complete tear suspected
What is Gamekeeper's Thumb?
Gamekeeper's thumb is an injury to the ligament on the inner side of your thumb. It often happens when your thumb is forced outward suddenly — commonly from a skiing fall or catching a ball.
What Are the Symptoms?
- Pain and swelling at the base of the thumb
- Weakness when pinching
- Feeling of instability
What is a Stener Lesion?
This is when the torn ligament gets caught on the wrong side of nearby tissue. This stops it healing on its own, so surgery is needed.
How is It Treated?
- Mild tears: Splint for 6 weeks
- Complete or Stener lesion: Surgery to repair the ligament
What's the Outlook?
With proper treatment, most people make a full recovery.
Primary Resources
- British Society for Surgery of the Hand. UCL Injury.
Key Studies
- Stener B. Displacement of ruptured UCL of the thumb MCPJ. J Bone Joint Surg Br. 1962;44-B:869-879. PMID: 14042224