Wrist sprain” is the label often given to persistent wrist pain after a fall. There are many possible causes, and a simple bruise or a ligament stretch is the most common. But in some cases, a scapholunate injury leads to chronic pain. So how do we diagnose a chronic scapholunate ligament tear — also called an SL ligament tear — and what do we do about it?
What is the scapholunate ligament?
The scapholunate ligament is a large, complex structure connecting two key wrist bones — the scaphoid and the lunate. It has three parts: ventral, dorsal, and interosseous. Together they support the bones and stabilise the joints between them.
Damage to this ligament allows the scaphoid and lunate to move apart and out of alignment. That instability is important, because — left untreated — it leads to a predictable pattern of early wrist arthritis. This is why an SL tear shouldn’t be dismissed as “just a sprain”.
How is the scapholunate ligament injured?
Most SL ligament tears follow a fall or direct trauma to the wrist — typically landing on an outstretched hand. But an injury can also occur without a fall: constant high loading of the wrist, as in weightlifting or gymnastics, can tear the ligament over time.
How is an SL ligament tear diagnosed?
People usually report pain and swelling after a fall or wrist injury. The pain tends to persist despite rest, and worsens with activities that load the wrist — weightlifting, tennis, or lifting heavy objects. Clicking and weakness are common too.
Examination often reveals tenderness over the SL ligament, on the back of the wrist. Your doctor may perform specific stability tests, such as Watson’s (scaphoid shift) test.
Imaging is essential — and this is where SL tears are commonly missed:
- X-ray — checks how the wrist bones sit together. A good-quality X-ray can show an SL tear, but most miss it. A dynamic clenched-fist X-ray loads the ligament and widens the gap between the scaphoid and lunate, making the tear easier to see.
- High-resolution MRI — shows the extent of the tear and rules out other causes, such as a scaphoid fracture.
- Ultrasound — useful for a dynamic assessment and for detecting an associated ganglion.
What about a scapholunate ganglion cyst?
A fall that sprains or partially tears the ligament can, over time, lead to a fluid-filled ganglion cyst forming over it — an SL ligament ganglion. As it grows, it can press on nearby structures and cause pain, especially on wrist movement. Ultrasound or MRI clearly shows the ganglion.
How do we treat a scapholunate ligament tear?
Treatment depends on the extent of the injury.
- Partial tears — a wrist splint for about four weeks, followed by hand therapy to rebuild wrist strength and function.
- Complete tears — surgery to repair or reconstruct the ligament is often needed, because a complete tear left alone leads to progressive instability and arthritis.
- An associated ganglion — aspirating the cyst with a needle under ultrasound is usually enough, and a small dose of cortisone can stop it refilling.
Frequently asked questions about a scapholunate ligament tear
Why was my scapholunate injury missed on X-ray?
Because a standard X-ray misses most SL tears, the bones can look normal at rest, and the gap only opens up under load. A dynamic clenched-fist X-ray — or an MRI — is far more reliable, which is why persistent wrist pain after a fall deserves proper assessment rather than being written off as a sprain.
What happens if a scapholunate tear is left untreated?
An untreated complete tear allows the scaphoid and lunate to drift apart and rotate, which over time leads to a specific pattern of wrist arthritis (sometimes called a SLAC wrist). This is the main reason early diagnosis matters — treating it early can prevent that long-term joint damage.
Can a scapholunate ligament tear heal without surgery?
Partial tears often do, with a period of splinting followed by hand therapy. Complete tears usually need surgical repair or reconstruction, because the instability won’t resolve on its own. The right approach depends on how much of the ligament is torn and how unstable the wrist is.
How do I know if it’s a scapholunate injury or a scaphoid fracture?
Both follow a fall on an outstretched hand and can feel similar. A scaphoid fracture causes tenderness in the “anatomical snuffbox” and is a bone injury; an SL tear causes tenderness a little further back over the ligament and is a soft-tissue injury. Imaging — X-ray and MRI — distinguishes them, and both are important not to miss.
How long does recovery take?
A partial tear treated with splinting and hand therapy typically settles over a couple of months. A surgically repaired complete tear takes longer, with a graded rehabilitation programme to restore strength and movement. Early, accurate diagnosis gives the best result in both cases.
Final word from Sport Doctor London about a scapholunate injury
Wrist sprains can be tricky to diagnose because of the wrist’s complex anatomy. It’s important to see a doctor to rule out serious causes — a fracture or a chronic scapholunate ligament tear — because a missed SL tear can lead to instability and early arthritis. Early detection and treatment are the key to preventing further damage.
If you have persistent wrist pain after a fall, Dr Masci can assess you in London, including in-clinic ultrasound. Contact the team here or call +44 (0) 203 488 0350.
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