A scapholunate ligament tear is an injury to an important ligament in the wrist. The ligament connects two small wrist bones—the scaphoid and lunate—and helps them move together in a coordinated way.
When the scapholunate ligament is stretched or torn, the scaphoid and lunate may no longer remain properly aligned during wrist movement. This can cause pain, weakness, clicking, and instability. More advanced injuries can alter the mechanics of the wrist and, over time, contribute to arthritis.
Scapholunate ligament injuries can be difficult to diagnose. A partial or early-stage tear may not appear on an ordinary X-ray, and symptoms can resemble those of a wrist sprain. Persistent pain after a fall or other wrist injury should therefore be evaluated by a qualified medical professional.
What Is the Scapholunate Ligament?
The wrist contains eight small bones known as the carpal bones. Two of these bones—the scaphoid and lunate—sit near the center of the wrist and play an important role in wrist motion and stability.
The scapholunate ligament, also called the scapholunate interosseous ligament, connects these two bones. It has three main portions:
- The dorsal portion, located on the back of the wrist, provides much of the ligament’s mechanical strength.
- The proximal portion is composed largely of fibrocartilage.
- The volar portion, located toward the palm, helps guide rotational movement.
The ligament works with other surrounding ligaments and joint structures to keep the scaphoid and lunate aligned as the wrist bends, rotates, grips, and bears weight.
A scapholunate ligament injury can range from stretching or a partial tear to complete rupture with substantial instability between the two bones.
What Causes a Scapholunate Ligament Tear?
The most common cause is a forceful load through an extended wrist. This frequently happens when a person falls onto an outstretched hand with the palm facing the ground.
Traumatic causes can include:
- Bicycle accidents
- Motorcycle or motor vehicle accidents
- Slip-and-fall incidents
- Contact sports
- Gymnastics or weight-bearing athletic activities
- A direct blow to the wrist
- Forceful twisting or bending of the wrist
The same event may also cause a broken wrist, particularly a distal radius or scaphoid fracture. A fracture can sometimes draw attention away from an accompanying ligament injury.
Not every scapholunate tear results from one identifiable accident. Repetitive loading, chronic ligament degeneration, inflammatory arthritis, or conditions that weaken connective tissue may also damage the ligament over time.
What Are the Symptoms of a Scapholunate Ligament Tear?
Symptoms vary according to the extent of the tear and whether the injury has caused wrist instability.
Common symptoms include:
- Pain on the back or thumb side of the wrist
- Swelling and tenderness
- Pain when gripping, pushing, pulling, or bearing weight through the hand
- Reduced grip strength
- Wrist stiffness or limited motion
- Clicking, popping, or clunking during movement
- A feeling that the wrist is weak or unstable
- Pain when rising from a chair by pushing down on the armrests
- Difficulty performing activities such as opening jars, lifting objects, or doing push-ups
Pain may initially improve with rest even though the ligament remains injured. Some partial tears cause only mild or intermittent symptoms, while complete tears can produce significant pain and mechanical instability.
Because these symptoms can resemble a routine wrist sprain, a scapholunate injury may go unrecognized—especially when initial X-rays appear normal.
Where Is Scapholunate Ligament Pain Felt?
Pain is usually felt near the center of the back of the wrist, often slightly toward the thumb side. The area may be tender when pressed.
Symptoms are commonly aggravated by gripping, extending the wrist, loading the wrist, or moving it toward the thumb. However, the location of pain alone cannot confirm the diagnosis because several fractures, tendon injuries, and other ligament conditions can cause similar symptoms.
Degrees and Stages of Scapholunate Injury
Scapholunate injuries may be described according to whether the tear is partial or complete and whether abnormal movement or alignment can be detected.
Predynamic or occult injury
A predynamic injury generally involves a partial tear or stretching of the ligament without measurable separation between the scaphoid and lunate. Standard and stress X-rays may appear normal.
“Occult” means the injury is hidden on routine imaging—not that the patient has no symptoms.
Dynamic instability
With dynamic instability, the ligament injury allows the scaphoid and lunate to separate under load. Standard X-rays taken while the wrist is at rest may appear normal, but stress or clenched-fist views may reveal abnormal widening.
Static instability
Static instability is present when abnormal spacing or alignment can be seen on ordinary X-rays without placing the wrist under stress. It generally indicates a more advanced injury involving the scapholunate ligament and potentially other stabilizing structures.
Scapholunate advanced collapse
Scapholunate advanced collapse, commonly called SLAC wrist, is a pattern of progressive wrist arthritis that can develop after longstanding scapholunate instability.
SLAC wrist is not simply another type of acute tear. It is a possible late consequence of chronic instability and abnormal joint loading. Not every scapholunate injury progresses to SLAC wrist.
How Is a Scapholunate Ligament Tear Diagnosed?
Diagnosis usually involves a medical history, physical examination, and one or more imaging studies. No single test identifies every scapholunate injury.
Medical history
A clinician will ask how the injury occurred, where the pain is located, how long symptoms have been present, and which movements make them worse.
Details about a fall, sudden impact, previous fracture, repetitive wrist loading, or prior wrist injury can help guide the evaluation.
Physical examination
The clinician may examine the wrist for swelling, tenderness, loss of motion, weakness, or mechanical clicking.
One examination method is the scaphoid shift test, also known as the Watson test. During this test, the examiner applies pressure over the scaphoid while moving the wrist. Pain or a noticeable clunk may suggest scapholunate instability, although the test cannot confirm a tear by itself.
The opposite wrist may also be examined for comparison because wrist flexibility and ligament laxity vary among individuals.
X-rays
X-rays do not show the ligament directly. They can, however, reveal changes in the spacing or alignment of the scaphoid and lunate. They are also useful for identifying fractures and arthritis.
Early or partial tears may not cause abnormalities on standard X-rays. When instability is suspected, a clinician may order specialized images, including:
- Clenched-fist views
- Grip views
- Radial or ulnar deviation views
- Comparison views of the opposite wrist
These stress views can reveal abnormal separation that appears only when the ligament is placed under load.
MRI
Magnetic resonance imaging can visualize ligaments and other soft tissues. It may identify a tear and associated injuries, but a normal MRI does not always exclude a partial or small scapholunate tear.
Results depend on factors such as the MRI technique, magnet strength, tear location, injury severity, and the experience of the interpreting radiologist.
MR arthrogram
An MR arthrogram is performed after contrast material is injected into the wrist joint. The contrast may make certain ligament defects easier to identify than they would be on a conventional MRI.
This test can provide useful information, but it is not perfectly accurate and must be interpreted together with the symptoms and examination findings.
CT and CT arthrography
A CT scan provides detailed images of the bones and may help assess abnormal alignment, fractures, or arthritic changes. CT arthrography combines CT imaging with contrast injected into the joint and may help identify ligament defects in selected cases.
Diagnostic wrist arthroscopy
During wrist arthroscopy, a surgeon inserts a small camera into the joint through a tiny incision. This allows the ligament, cartilage, and surrounding structures to be examined directly.
Arthroscopy is generally regarded as the most definitive method of evaluating a suspected scapholunate ligament injury. It can establish the location and severity of the tear and may allow treatment to be performed during the same procedure.
Because it is invasive, arthroscopy is not necessarily the first test used in every case.
Why Can a Scapholunate Tear Be Missed?
Several factors can make the injury difficult to recognize:
- Initial X-rays may be normal.
- Swelling and pain may be attributed to a wrist sprain.
- A fracture may occur at the same time and receive most of the attention.
- Partial tears may produce inconsistent symptoms.
- MRI does not identify every tear.
- Abnormal spacing may appear only when the wrist is under load.
- Symptoms may temporarily improve with rest or immobilization.
A person whose wrist pain, weakness, or clicking persists after an injury should consider further medical evaluation even if the initial X-rays did not reveal a fracture.
What Conditions Can Cause Similar Symptoms?
A clinician may need to distinguish a scapholunate ligament tear from other causes of wrist pain, including:
- Scaphoid fracture
- Distal radius fracture
- Triangular fibrocartilage complex injury
- Other carpal ligament injuries
- De Quervain’s tenosynovitis
- Ganglion cyst
- Tendon injury
- Wrist arthritis
- Avascular necrosis of a wrist bone
- Nerve compression
This is one reason imaging findings should be considered together with the patient’s history and physical examination.
How Is a Scapholunate Ligament Tear Treated?
Treatment depends on the age and severity of the injury, whether the tear is partial or complete, whether the bones remain properly aligned, and whether arthritis is already present.
Nonsurgical treatment may be appropriate for a sprain, partial tear, or stable injury. It can include:
- Activity modification
- A wrist splint or cast
- Ice during the initial stage of injury
- Medication when medically appropriate
- Hand therapy or physical therapy
- Gradual strengthening after immobilization
A complete tear, persistent instability, or injury that does not improve with conservative care may require surgery. Procedures vary and may include arthroscopic treatment, ligament repair, reconstruction, temporary pinning, or another operation intended to stabilize the wrist.
When advanced arthritis is present, treatment may focus on relieving pain rather than reconstructing the original ligament. Options can include partial wrist fusion, removal of certain wrist bones, or other salvage procedures. Total wrist fusion is generally reserved for severe cases.
Can a Scapholunate Ligament Tear Heal on Its Own?
A mild sprain or stable partial injury may improve with protection and immobilization. A complete tear is less likely to restore normal ligament anatomy and stability without treatment, particularly once the injury becomes chronic.
Improvement in pain does not necessarily mean that a complete tear has healed. The appropriate follow-up depends on the extent of the injury and whether the wrist remains stable.
Recovery and Prognosis
Recovery varies substantially. Important factors include:
- Whether the tear is partial or complete
- The degree of wrist instability
- How long the injury was present before treatment
- Whether associated fractures or cartilage injuries occurred
- The presence of arthritis
- The treatment performed
- The patient’s age, health, occupation, and activity demands
Some stable injuries respond well to nonsurgical treatment. After surgery, immobilization is often followed by hand therapy, and recovery may take several months. The precise timeline depends on the procedure and the surgeon’s rehabilitation protocol.
Some patients experience lasting stiffness, reduced grip strength, or limits in wrist motion. Others regain useful function and return to work, exercise, and daily activities. It is therefore not accurate to assume that everyone with this injury will have lifelong pain or require permanent treatment.
Earlier assessment can be important because a recent, repairable tear may have different treatment options than a chronic injury with fixed instability or arthritis.
When Should You Seek Medical Attention?
Prompt evaluation is appropriate after a significant wrist injury, especially when there is severe pain, deformity, extensive swelling, numbness, discoloration, or an inability to move the wrist or fingers.
A medical evaluation is also advisable when:
- Wrist pain continues after an apparent sprain
- Pain improves but returns with gripping or weight-bearing
- The wrist clicks, clunks, or feels unstable
- Grip strength remains reduced
- Swelling or tenderness does not resolve
- Symptoms interfere with work, sports, or daily activities
This article provides general educational information and is not a substitute for diagnosis or treatment by a qualified healthcare professional.
If your scapholunate ligament injury resulted from an accident and you have questions about your legal options, visit our separate scapholunate ligament injury claim page.
