Ligaments are tough pieces of connective tissue that join one bone to another. Ligaments are attached on either side of a joint, strengthening and stabilizing it by limiting excess motion of the bones. Injuries to ligaments are very common; in fact, what we call a sprain is actually an injury to the ligaments of the “sprained” joint. The hand and wrist are particularly susceptible to ligament injuries simply because it gets so much use and thus is exposed to many possibilities for injury. One common place for a hand ligament injury to occur is in the scapholunate ligament.
The reason that ligament injuries in the wrist are so complex is because the wrist joint is very complicated. There are eight smaller bones through the wrist, called the carpal bones. These act as a transition area between the larger arm bones (the radius and the ulna) and the smaller bones in the hand. Ligaments connect all the tiny bones inside the wrist to each other, and also connect the wrist bones to the ulna and radius as well as the bones in the hand (metacarpals).
The ligaments are important for maintaining balanced movement throughout the wrist. An injury to even one of these many ligaments affects the way the bones are able to move together. Instead of moving as a single unit, the motions become out of sync; the wrist joint become unstable. This causes pain and friction in the wrist joint that can promote the development of other joint problems like arthritis.
In case of trauma to the wrist, whether or not the ligament is damaged depends on a number of different factors, like the amount of force, bone strength and the angle of the wrist at the time of injury. Signs of a ligament injury include pain and swelling that’s similar to many other hand and wrist injuries. The wrist may also look bruised or discolored, and feel painful for several weeks.
In some cases, a ligament injury may go undiagnosed, causing the joint to heal improperly. Although the severity of the symptoms may ease up, ongoing pain and a feeling of clicking inside the wrist during gripping movement can continue over the long-term.
X-rays may be used to determine bone placement in order to see which ligaments may be affected. A special dye injection can also help map out the ligaments; this is called an arthrogram. An MRI can also help diagnose problems in the ligaments and other soft tissues. Sometimes proper diagnosis is one of the biggest challenges in treating any type of wrist injury.
The scapholunate ligament is responsible for ensuring that the two bones – scaphoid and lunate move in unison. This ensures smooth rotation of the wrist. When this hand ligament is torn, the scaphoid and lunate move in different directions, which results in pain and loss of strength when gripping.
While hand ligament injuries are often obvious due to the local pain and swelling that accompanies them, the severity of such injuries is easy to misjudge. Symptoms vary depending on the severity of the injury, but commonly include pain on the thumb side of the wrist, swelling and/or bruising, loss of grip strength, and sometimes a snapping or popping in the wrist.
Like tendons, ligaments are made up of many tough fibers, and the severity of the injury depends on how many fibers are involved and how completely they are involved. Any number of ligament fibers may be injured, from one or two to all of them. They may only be inflamed or bruised, or they may be completely torn. When all of the fibers are torn, this is described as a complete scapholunate ligament tear.
Treatment for ligament injury depends on how serious the trauma is. A minor wrist sprain can be treated with a specially fabricated splint that lets healing occur while the wrist is held in correct alignment. If the ligament is torn and joint misalignment is noted, there are a few surgical approaches that can help:
Pinning/Repair: Ligament damage that’s recognized fairly early (within a few weeks of injury) can be repaired by the insertion of metal pins to stabilize the bones, which allows the ligaments to heal. After healing, the pins are removed. This is less likely to be helpful if too much time has passed since the injury.
Arthroscopy: Arthroscopic surgery can be used to access and repair ligaments in the wrist. Wrist arthroscopy enables the surgeon to see the wrist anatomy and ligament movements without the need for large incisions into the muscle and tissue.
Reconstruction: For injuries that occurred six months or more before treatment, reconstruction of the ligament may be needed. A tendon graft is used to replace the torn ligament, and the wrist is temporarily held in place with metal pins throughout the initial healing process.
Fusion: If arthritis is already present, fusion of the joint may be needed to reduce joint pain during movement and stabilize the area.
In many cases, a combination of these techniques may be used. Treatment is customized to the specific ligament injury and the needs and preferences of each patient.
After surgery, patients wear a splint or cast at first. Once this is removed, some patients notice stiffness in their wrists, while others notice a limited range of motion. Hand therapy is often incorporated as part of the recovery process to ensure proper joint alignment and function recovery during healing.