Scapholunate Ligament Injury

Scapholunate ligament between scaphoid and lunate bones
Figure 1. The scapholunate ligament is between the scaphoid and lunate bones.

A ligament is a thick band of tissue that connects two bones. A common ligament injured in a sprained wrist is the scapholunate ligament, located between the scaphoid and lunate bones. This ligament is important for painless and full wrist motion.

Scapholunate ligament injuries can range from stretching to a complete tear. Any injury can make the wrist unstable and painful.

Causes

The scapholunate ligament usually tears when a large amount of stress is placed on the wrist, often after a fall onto the hand. It is typically injured when the wrist bends backward or into an unusual position. The ligament may also stretch out over time due to repeated strains, aging, longstanding inflammation, or chronic gout.

Signs and Symptoms

An injured scapholunate ligament often causes wrist swelling and pain, especially with certain motions.

  • Pain when bending the wrist backward
  • Limited range of motion
  • Bruising
  • Pain and swelling that develop over several days, usually on the back side of the wrist
  • Popping or grinding
  • Weakness in the wrist

Symptoms may happen immediately after injury, persist, or worsen over time. Some people notice problems years after the initial injury.

X-ray showing scapholunate gap
Figure 2. X-ray showing a gap between the scaphoid and lunate compared with a normal x-ray.

Diagnosis

Diagnosis can be difficult. A doctor will examine the wrist, check where it hurts, evaluate motion, and compare the injured wrist with the uninjured wrist. X-rays can show changes in wrist bone spacing and alignment. When the ligament is injured, the scaphoid and lunate may move apart, creating a visible gap.

MRI may be needed to confirm the diagnosis and show the degree of ligament injury. Sometimes dye is injected into the joint before MRI, called an MR arthrogram. Wrist arthroscopy may also be used so the surgeon can directly evaluate the wrist ligaments.

Treatment

A torn scapholunate ligament does not heal on its own. If left untreated, it can lead to arthritis over time because the wrist bones are no longer held in normal alignment. Treatment goals are to reduce pain and help prevent arthritis.

For a recent injury, early treatment may include pain control, a wrist splint or cast, activity reduction, and rest. Hand therapy may help if the wrist is stiff after immobilization. Cortisone injections and anti-inflammatory medications may reduce pain but do not correct wrist bone alignment.

If non-operative treatment does not work, surgery may be considered to repair or reconstruct the ligament and improve wrist alignment. Chronic injuries may require other options focused on pain control and function, such as wrist denervation, removal of some bones, or partial wrist fusion.

This mobile-friendly version is adapted from patient education content originally provided by the American Society for Surgery of the Hand.