What is the treatment for a thumb sprain?

Treatment of Thumb Sprain

For minor thumb sprains without laxity, immobilize with a thumb spica splint or cast for 4 weeks; for severe sprains with laxity or complete ulnar collateral ligament rupture, surgical repair is necessary to prevent chronic instability and achieve optimal functional outcomes. 1, 2

Initial Assessment and Classification

The critical first step is determining the severity of injury through bilateral comparative examination to detect laxity at the metacarpophalangeal (MCP) joint 3:

• Minor sprains (no laxity): Partial ligament injury without joint instability 3
• Severe sprains (with laxity): Complete ligament rupture, often involving the ulnar collateral ligament (86% of cases) 1
• Stener lesion: Displaced ligament that cannot heal without surgery 3

The mechanism is typically excessive extension or radial deviation of the thumb, commonly occurring during sports (50% of cases), particularly skiing, hockey, and boxing 4, 1

Treatment Algorithm

For Minor Sprains (No Laxity)

• Immobilize with thumb spica cast or rigid splint for 4 weeks 3
• Taping alone is acceptable for very minor injuries 4
• Begin rehabilitation at week 4 to reduce stiffness risk 3

For Severe Sprains (With Laxity)

Surgical repair is strongly recommended and produces 90% good to excellent results when followed by proper physical therapy 1:

• With Stener lesion: Surgery is mandatory to reattach the ulnar collateral ligament to the proximal phalanx base 4, 3
• Without confirmed Stener lesion: Consider ultrasound or MRI to rule out underlying Stener effect, as treatment choice remains contentious 3
• Surgical reattachment should be performed acutely for best outcomes 4, 1

Post-Treatment Rehabilitation

• Start physical therapy at week 4 regardless of treatment method to prevent stiffness 3
• Return to sports depends on injury severity and ability to wear protective rigid splint 3
• Supervised exercises focusing on strength and function are essential 1

Common Pitfalls

• Missing the diagnosis: Severe sprains are frequently overlooked, leading to chronic instability that requires more complex surgical intervention 2
• Delayed surgery: Chronic instability (missed acute injuries) has worse outcomes, with ligament reconstruction producing inferior results compared to acute repair 2
• Inadequate immobilization: Minor sprains require full 4 weeks of immobilization; premature mobilization risks chronic laxity 3
• Skipping rehabilitation: Early physical therapy at week 4 is critical to prevent permanent stiffness 3

Chronic Instability Management

If diagnosis is missed and chronic instability develops 2:

• Primary repair is preferred when feasible (87.3% patient satisfaction, mean Quick-DASH 17.4) 2
• Arthrodesis provides excellent pain relief and 94% pinch strength compared to normal side 2
• Ligament reconstruction has higher failure rates (60% residual instability) and is not recommended over arthrodesis 2