What type of brace is used for a Ulnar Collateral Ligament (UCL) injury of the thumb while waiting for a Magnetic Resonance Imaging (MRI)?

Thumb Spica Brace for UCL Injury While Awaiting MRI

For thumb ulnar collateral ligament (UCL) injuries awaiting MRI, a hand-based thumb spica brace or cast is the recommended immobilization method to protect the injured ligament and prevent further damage.1, 2

Brace Selection and Application

• A hand-based thumb spica brace is preferred over a forearm-based design as it allows continued wrist motion while immobilizing the thumb metacarpophalangeal (MCP) and interphalangeal (IP) joints1
• The brace should immobilize the thumb in a functional position while leaving the wrist free to move2
• The thumb spica should be properly fitted to prevent displacement of the torn UCL ends and potential development of a Stener lesion (where the adductor aponeurosis becomes interposed between the ruptured UCL and its insertion site)3

Diagnostic Considerations

• MRI is the imaging modality of choice for definitive diagnosis of thumb UCL injuries, with reported sensitivity of 100% and specificity of 94% for detection of displaced UCL tears4
• While awaiting MRI, clinical examination remains crucial for initial assessment of UCL stability3
• Ultrasound can also be used to identify Stener lesions, characterized by absence of the UCL and presence of a hypoechoic mass proximal to the metacarpal tubercle4

Duration of Immobilization

• The thumb should remain immobilized in the spica brace until MRI results are available and definitive treatment is determined1
• For non-surgical cases of incomplete tears, immobilization typically continues for 4-6 weeks2
• For cases requiring surgical repair, the thumb spica brace is often continued postoperatively for protection5

Functional Considerations

• The hand-based thumb spica design allows the patient to maintain grip function and wrist mobility while protecting the injured UCL1
• This design permits continued participation in many activities of daily living with less functional limitation than a full forearm-based cast1, 2
• For athletes or workers with high demands, custom-made removable splints may be considered after initial immobilization period6

Potential Complications

• Inadequate immobilization may lead to chronic instability or development of a Stener lesion requiring surgical intervention3
• Overly rigid or prolonged immobilization can lead to stiffness and delayed functional recovery2
• Adjacent joint dislocations have been reported in athletes returning to play with thumb spica casts, suggesting the need for careful activity modification while braced5

Modified Approaches

• For certain patients, a modified functional hand-based splint that allows some controlled early motion of the MCP joint may be considered after surgical repair to prevent stiffness2
• However, standard rigid immobilization remains the safest approach while awaiting definitive diagnosis via MRI1