Scapholunate Ligament Injury

Ligaments are the strong connective tissue that help stabilize bones to one another. A “sprain” is an injury to the ligaments and can range from a mild injury in which the ligament is stretched to a more severe injury in which the ligament is torn.

A commonly injured ligament in the wrist is the scapholunate (or “SL”) ligament. This is an important ligament in the middle of the wrist that connects the scaphoid and lunate bones to one another. Its integrity is critical for support and proper function of the wrist and hand.

Injury to the ligament often occurs from a sudden injury in which stress is applied to the ligament from a fall. However, the scapholunate ligament may also be injured from repeated low energy strain or overuse injuries.

Milder injuries may result in pain with use of the hand and wrist, particularly with forceful gripping or pushing activities. More severe injuries may result in instability of the bones in the wrist. Because of this abnormal motion of the bones, this can lead to worsening arthritis over time. This particular pattern of arthritis is known as “scapholunate advanced collapse” (SLAC). For this reason, early recognition and treatment of scapholunate ligament injuries is important.

Initial evaluation includes a detailed examination of the hand and wrist. X-rays are used to look at the position of the bones in the wrist, including the scaphoid and lunate bones. This includes assessment for a “DISI deformity” in which the lunate bone is abnormally tilted and for widening or gapping at the “scapholunate interval”. Sometimes, a “pencil grip” x-ray is performed, which is a special x-ray view intended to evaluate the scapholunate ligament. Because ligaments cannot be seen on x-ray, an MRI sometimes is used to better evaluate the ligaments in the wrist, including the scapholunate ligament.

Depending on the severity of the injury, initial treatment may involve resting and minimizing use of the wrist by wearing a splint or cast. If this is not successful in healing the injury and resolving the associated pain or if there is a more severe injury, then surgery may be required.

Wrist arthroscopy is a surgical procedure in which a small camera is inserted into the wrist. This permits careful evaluation of the scapholunate ligament (and other structures in the wrist). Inflamed tissue, which can cause pain within the wrist, can be debrided (or removed) arthroscopically. If an injury to the scapholunate ligament is detected, then this can be treated arthroscopically or with an open surgery in which an incision is made on the wrist.

For lower grade injuries in which the ligament is not completely torn, then treatment may require only arthroscopic debridement followed by pinning to stabilize the scaphoid and lunate bones. These metal pins typically are left in place temporarily for 1-2 months before being removed.

If the ligament is completely torn and the injury happened relatively recently, which is known as an “acute” injury, then repair of the ligament may be possible. This usually is done with an open surgery in which an incision is made on the wrist. This permits identification of the torn scapholunate ligament, which can then be repaired back to the bone.

If the ligament is completely torn but the injury happened more than several months ago, which is known as a “chronic” injury, then reconstruction of the ligament may be necessary. This is the case when repair is not possible due to scarring and contraction of the ligament, which occurs over time following an injury. There are many methods to reconstruct the scapholunate ligament, but this typically involves using a small piece of donor tendon from another area on the wrist. It is then attached to the scaphoid and lunate bones to help pull them together and re-establish their natural relationship with one another.

If the scapholunate ligament injury has resulted in SLAC arthritis, then a salvage procedure may be necessary. These arthritic changes in the bone are due to degeneration of the cartilage, which would cause persistent pain, even if the scapholunate ligament were reconstructed. Treatment options depend on multiple factors including severity of the pain, goals of the patient, and associated medical problems. These treatments may include joint denervation, removal of the arthritic bones in a procedure known as a “proximal row carpectomy”, partial fusion of the bones in the wrist in a procedure known as a “four corner fusion” or “four bone fusion”, or total fusion of the bones in the wrist. Although a fusion will take away some or all of the motion in the wrist, these procedures stabilize the bones so that they do not grind on one another and cause pain resulting from arthritis.

Choosing between these many treatment options requires a careful evaluation by your surgeon and a detailed discussion between the patient and the surgeon.

Recovery is highly dependent on which procedure is performed. With many of the procedures, including repair, reconstruction, or fusion, a prolonged period of immobilization in a splint or cast may be necessary. Joint denervation procedures often have the quickest recovery. Hand therapy often is needed to help with recovery, including regaining strength and range of motion. After recovering from surgery, patients should have significant improvement in the pain in their wrist, but there may be a noticeable decrease in their wrist range of motion. However, most people can return to their normal daily activities and even high-impact sports.

Be sure to see an experienced surgeon to treat this condition. Our fellowship-trained specialists at The Buncke Clinic in San Francisco treat patients with scapholunate ligament injuries from across the Bay Area and Northern California. Contact us to schedule a consultation.

Below are links for third party resources

American Society for Surgery of the Hand

American Academy of Orthopaedic Surgeons