There are numerous bones in the wrist, any one of which can be fractured. The most likely bone to be fractured is the scaphoid bone, which is involved in 68 percent of carpal fractures. Triquetrum fractures happen in 18 percent of cases, and the rest is rarely fractured. The most proximal row of bones in the wrist are most likely to become fractured. The proximal row consists of the scaphoid bone, the lunate bone, the triquetrum bone, and the pisiform bone. The distal row of bones in the wrist is relatively stable due to supporting ligaments that keep it relatively immobile. There are multiple ligaments inside the wrist joint area so that these bones are relatively spared from displacement, even when fractured.Mechanism of Injury
The most commonly fractured wrists occur after a fall to the outstretched hand with the wrist hyperextended. The ligaments on the palm side of the hand get stretched, and there are shear forces that are applied to the backside of the wrist, resulting in fracture. The wrist is essentially extended beyond its normal physical ability.
The patient with a wrist fracture presents with well-localized tenderness in the wrist. There may be deformity of the wrist so that some of the bones stick out from the other bones. X-rays can be taken of the AP and lateral view to see which bones are fractured if any. A scaphoid view is a special x-ray of the scaphoid bone that shows the fracture better than the regular x-ray views. Arthrography, MRI scans or CT scans may need to be done to show the exact alignment of the bones when compared to one another. There are other views that can be taken on x-ray to show if the ligaments are damaged even when the bones themselves are not fractured.Scaphoid Fractures
These account for up to 80 percent of all wrist fractures. The scaphoid bone is an oblong bone that can be fractured at any level. There are two areas of vascular supply to the scaphoid and union of the fracture depends on getting blood supply from both parts of the bone. With this type of fracture, the patient presents with wrist pain and swelling with tenderness directly over the scaphoid bone. Up to twenty-five percent of the time, x-rays in the usual AP and lateral views will not show a fracture even when there is one. Sometimes re-x-ray after 1-2 weeks will show widening of the fracture fragments, indicating a fracture. CT and MRI scans can be helpful in determining if the bone is broken, especially when a break is suspected but cannot be seen on x-ray.
These fractures can be treated without surgery when they are nondisplaced and occur at the distal third of the bone. The person is placed in a long arm thumb spica cast for six weeks with limited mobility of the forearm to rotate. It can take up to 24 weeks to heal a scaphoid fracture, especially if the proximal one third is fractured. Proximal pole fractures heal only about 60-70 percent of the time when not treated surgically. Proximal fractures are prone to nonunion and bony death of part of the fractured bone.
Surgery may be required if there is displacement or angulation of the fracture or if there is nonunion of the fracture. Most surgical techniques involve the use of screws to hold the bone together. Complications include nonunion or delayed union of the scaphoid bone. This usually happens when there is a delay in treatment of the fracture. Osteonecrosis is another type of complication that occurs when the blood supply to the fractured segment is cut off by the fracture.Wrist Dislocations
A wrist dislocation can happen anytime there is significant ligamentous disruption about the wrist joint. Direct force on the wrist or a fall on the outstretched hand are typical causes of a wrist dislocation. Dislocations can be identified by x-ray followed by CT scan or MRI scan of the affected area. Most dislocations can be treated with closed reduction and traction on the wrist. Complications include post-traumatic arthritis of the wrist and recurrent instability of the wrist joint if the ligaments didn’t adequately heal.Ligamentous Dissociations
There are several types of ligamentous dissociations that can occur as part of the injured wrist. These can be treated by using a cast or splint for six weeks or by doing surgery to fix the tear in the ligament. Ulnar neuropathy can complicate this type of injury as can recurrent instability of the joint.
In the following video, Dr. Sanj Kakar with Mayo Clinic explains what you can do to relief your injured and achy wrists.Sacramento Traumatic Injury Lawyer
I’m Ed Smith, a Traumatic Injury Lawyer in Sacramento. If you or a loved one has suffered injuries in an accident, call me today at (916) 921-6400 or (800) 404-5400 for free, friendly advice.
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Editor’s Note: This page has been updated for accuracy and relevancy [cha 5.9.19]