How Long Should a Sprained Thumb Hurt? Sprain Grades

Grading of a sprain is based on the extent of the ligament damage:

• First degree sprain: Minor injury in which the ligament is strained but not ripped. When the damaged joint is subjected to a ligament stability test, the joint stays stable and the ligament remains tight. However, stretching the thumb may cause pain, and there may be some swelling and tenderness around the affected area.
• Second degree sprain: Moderate injury where there is a partial tear to the ligament, which results in instability of the joint. The thumb may move sideways or slide back more than its normal extension. There may be pain and disability of the thumb immediately following the injury.
• Third degree sprain: Severe injury where there is a complete rupture of the ligament and in some cases a bone fracture. This injury causes deformity, discoloration, swelling, point sensitivity, and discomfort with movement. As a third degree ligament sprain is associated with a fracture, an athlete suspected of sustaining this sort of injury should be splinted and referred to medical care immediately.

A thumb sprain occurs when the ligament that joins the phalanx bones in the thumb is overstretched or torn. 

This type of injury can occur when the thumb is pushed backward with extreme force, such as with a fall with extended arms, which causes the ulnar collateral ligament of the thumb to stretch or tear. The ulnar collateral ligament is a strong band attached to the metacarpophalangeal joint that maintains thumb stability.

Thumb sprains are usually seen in:

• Skiing, as injuries are often caused by big ski poles
• Sports such as basketball and baseball
• Repetitive gripping or twisting activities may injure the ligament in the long run

Depending on the severity of the injury, symptoms of a sprained thumb may include:

• Pain
• Swelling
• Bruising
• Tenderness
• Weakness or loss of ability to grasp things between thumb and index finger
• Stiffness with little movement and difficulty performing regular movements

Physical examination

Your doctor will take your medical history and symptoms into consideration and check for signs to rule out a sprain. 

They may perform a ligament stress test to determine the extent of the tear. To examine the stability of the metacarpophalangeal joint, joints between the bone in the thumb and wrist are tested for movement. The doctor may move your thumb in various directions to determine whether the ligaments are torn partially or completely. Complete rupture of the ligament makes the joint loose and unstable.

Imaging studies

• X-ray: If your doctor confirms a complete ligament rupture, an X-ray may be done to check for possible fractures. Sometimes, both healthy and injured thumbs may be  X-rayed to note the difference between normal and injured ones. Stress X-rays may be done to assess the stability of the metacarpophalangeal joint. Pressure is applied on the thumb during the X-ray. This test may be painful, so a local anesthetic may be administered before performing the test.
• Magnetic resonance imaging (MRI): An MRI may be done to check for soft tissue damage.

Stabilizing the thumb with a splint, applying an ice pack within 20 minutes of the injury, and keeping the injured area elevated are the only treatment modalities for a sprain. You may also take over-the-counter painkillers to reduce pain and swelling.

A sprained thumb does not need any surgical intervention unless there is a complete tear or any associated fracture. If there is a fracture, a splint or a cast is applied for a period of at least 3-4 weeks.