What is Scapholunate Advanced Collapse (SLAC) of the Wrist?
Scapholunate advanced collapse of the wrist or SLAC is the most common pattern of degenerative osteoarthritis of the wrist.
Causes SLAC of the Wrist
The most common cause of SLAC of the wrist is a traumatic disruption of the scapholunate ligament. Other causes include:
- Avascular necrosis [AVN] of the scaphoid
- Midcarpal instability
- Intra-articular fractures
- Kienböck disease
- Inflammatory arthritis, as observed in the calcium pyrophosphate dihydrate deposition disease (CPPD) and crystalline deposition disorders of gout
Symptoms of SLAC of the Wrist
Symptoms include:
- Pain and weakness in the affected hand
- Stiffness of the wrist with dorsal radial swelling
- Difficulty holding a weight with the affected wrist
Treatment for SLAC of the Wrist
Treatment for SLAC of the wrist is based on your symptoms. Your doctor recommends non-surgical treatment for mild symptomatic SLAC which involves NSAIDs, wrist splinting and possibly steroid injections.
Surgical procedures used in treating SLAC of the wrist include:
- SLAC reconstruction (limited wrist fusion): Surgical treatment in the form of wrist ligament reconstruction may be indicated in cases where the wrist ligament is completely torn. The ligament usually will need to be reconstructed when ligament damage is noted after a period of 6 months or more following the initial injury. Ligament reconstruction procedure can be performed as day surgery under local or general anesthesia. During the procedure, your surgeon first makes an incision over your wrist joint to locate the torn ligament. Once located, a tendon graft (tissue obtained from a donor part, usually the palmaris longus tendon of the same wrist) is used to replace the torn ligament. The tendon is harvested through the bottom of your wrist via one or two minor incisions. Your surgeon may then place metal pins to support the repair while healing occurs. The surgical incisions are closed and dressing is applied.
- Arthroplasty of the wrist: In this procedure, your surgeon removes the affected joint and replaces it with an artificial implant. In patients with post-traumatic arthritis and osteoarthritis where the bone is hard and demand on the hand is moderate, new ceramic implants are used. These are not desirable to use for a severely damaged or unstable joint. In patients with inflammatory arthritis where the bone is not strong enough and the demand on the hand is low, older silicone rubber joints are generally used. These can be used for cases with more severe joint damage and an unstable joint.
- Total wrist arthrodesis: A fusion, also called an arthrodesis, involves removal of the joints and fusing the bones of the joint together using metal wires or screws. Even though this surgery eliminates all motion at the base of the thumb, the resulting fusion is very hard. This surgery is usually indicated when the joints are severely damaged, when there is limited mobility, damage to the surrounding ligaments and tendons, failed previous arthroplasty, and when heavy manual use is expected. Your surgeon will discuss the options and help you decide which type of surgery is the most appropriate for you.