Because of the large role the wrist plays in daily activities, it is often prone to stress and injury that results in pain and instability.
The proximal bones of the wrist – the scaphoid, lunate, and triquetrum – have no muscular attachment. With the help of many strong ligaments, their main purpose is to stabilize the wrist joint. Damage to any of these ligaments that bind the proximal bones together can result in a malalignment of the carpal bones, which, if left untreated, could cause abnormal wear and tear and eventually lead to osteoarthritis.
The most common ligamentous injury of the wrist is Scapholunate Instability. It is diagnosed when two of the three main ligaments that bind the Lunate and Scaphoid bones are significantly damaged. These ligaments include the Volar radioscapholunate ligament, the scapholunate interosseous ligament, and the dorsal scapholunate ligament.
Initially the symptoms of a ligament injury may result in pain, weakness and a sense of “giving way.” Often times the pain will subside after a few days even though carpal instability exists – unfortunately leading patients to believe a physical examination and subsequent treatment unnecessary.
Those at Risk
Ligament injuries and carpal instability most often occur in the young and middle aged, because they are more active and have stronger bones. Injury to the increasingly fragile bones of older patients most often results in a fracture rather than soft tissue damage.
With the right imaging and careful assessment, modifications in carpal bone contours or positions following an injury will confirm carpal instability. Early treatment is essential in preventing the development of osteoarthritis.
If diagnosed early enough a minor injury can be addressed with conservative treatment. This consists of splinting and the use of NSAIDs (non steroidal anti inflammatory drugs). But if the injury is determined to be severe, surgery is necessary to correct the alignment.
If carpal insufficiencies are left untreated, further shifts of the carpal bones may occur. In the case of scapholunate instability, the continuation of shifting can eventually lead to a condition known as scapholunate advanced collapse, or SLAC – and wrist fusion may be required.