Carpal Avascular Necrosis
Carpal Avascular Necrosis is the loss of necessary blood supply to a bone and most often results from the improper healing of a damaged carpal bone known as the scaphoid - following
a trauma and subsequent fracture. This is most commonly associated with damage to the scaphoid bone, because this particular carpal bone has only one small blood-supplying artery located near the
base of the thumb. A fracture that tears the artery severs the blood supply. This loss in blood supply will cause the bone to die and make union and bone healing unlikely, if undiagnosed.
Risk Factors
Patients sustaining a severe distal radius or wrist fracture affecting the scaphoid bone are at risk for carpal avascular necrosis. Though one of the
strongest carpal bones and most difficult to break, scaphoid fractures account for nearly 60 percent of all wrist fractures. Because it is so strong, the type of force required to damage the
scaphoid bone is that which is generally found in sports or severe accidents. An injury to the scaphoid occurs when the wrist joint of an outstretched hand hyperextends.
Men are much more likely to fracture this bone than women, because of the types of sports and activities in which they are involved - as well as the increased weight sustained
by the wrist joint during a push or fall.
Diagnosis and Treatment
The presence of avascular necrosis may not be initially evident upon early X-ray, though the severity of the fracture and progressive pain and tenderness
as bone density and shape begin to change will prompt further testing.
In advanced stages, fragmentation and collapse occur and degenerative arthritis is the end result.
Treatment of these Navicular Avascular Necrosis conditions depends on the condition of the bone, though early diagnosis increases the success of the
treatments. In the early stages, intermittent immobilization may be recommended in order to allow reconstitution of normal bony structure. A removable cast may also be used in conjunction with
range of motion exercises and targeted rehabilitation.
In advanced stages of these conditions, surgery is necessary. |
