Wrist Rescue

None — Wrist Fractures

The wrist is made of 8 tiny bones plus 2 bones in the forearm (the ulna and radius). All the bones meet together in joints, which enable the wrist to move in many different ways: side to side, up and down and in rotation.

Wrist fractures account for up to one-sixth of all fractures seen in U.S. emergency rooms. One of the most commonly broken wrist bones is the scaphoid bone, the small bone located on the inner wrist (at the base of the thumb). The fracture is usually caused by a fall onto an outstretched hand, with the palm taking the brunt of the impact.

A scaphoid fracture causes swelling and pain around the base of the thumb. The pain may be significant when trying to make a grasping motion or other movement of the thumb or wrist. If the fracture isn't severe, patients may not have a significant amount of pain.

Healing Problems

The traditional treatment for a wrist fracture is immobilization. The bones are aligned in their proper position and then a cast is placed on the affected arm. In some cases, surgeons also place screws and wires into the bones to hold them in place until the fracture has healed.

James Higgins, M.D., Hand and Reconstructive Plastic Surgeon with Union Memorial Hospital in Baltimore, MD, says the majority of people with a wrist fracture recover without any complications. However, in a minority of patients, the fracture doesn't heal, meaning the bones don't come together and fuse. This is called a nonunion. The most common cause of nonunion in a wrist fracture is an insufficient supply of blood to the site, which limits the amount of oxygen and nutrients to the healing fracture. Over time, the poor healing can lead to the development of arthritis in the affected wrist and loss of wrist function.

Vascularized Bone Grafting

When a wrist fracture fails to heal, doctors may consider another treatment, called vascularized bone grafting. A piece of bone and connecting blood vessels are taken from femur (thigh bone), in the area where the bone makes up the knee joint. Higgins says the size and shape of the donor bone are molded to fit into the recipient site. It can be as thin as a wafer or a thicker wedge. Next, the donor bone and attached blood vessels are placed at the site of the fracture. Then, using microscopic surgery techniques, the donor blood vessels are connected to the blood vessels in the wrist area. The connected blood vessels supply oxygen and nutrients to the donor bone, hopefully helping the fracture heal.

Higgins says vascularized bone grafting requires a minimum of two attached blood vessels – an artery to bring blood in and a vein to take deoxygenated blood out. Sometimes more than two vessels are taken to maximize a healthy blood supply. It generally takes two to three days to determine if the blood vessel connections have been successful. Full healing typically takes 8 to 12 weeks.

The Next Step

Higgins says sometimes vascularized bone grafting doesn't go far enough to preserve function of the wrist. That's because the scaphoid bone is normally covered with cartilage, to protect the bone from friction during movement. Traditionally, vascularized bone grafting involves the transfer of only the bone and blood vessels. Without the protective cartilage, the bones can rub, causing inflammation and eventually, arthritis.

Higgins says one of the advantages of the femur as a donor bone is that it is near an area of cartilage. He recently started taking cartilage in addition to bone when performing a vascularized bone graft for the wrist. Higgins says the vascularized bone and cartilage graft appears to speed healing. However, patients are still required to use a cast or splint until doctors are sure the bones have fused.

The vascularized bone and cartilage graft doesn't seem to have any effect on the donor site (the knee). Patients are able to walk around without braces or crutches after surgery. However, researchers are following patients to determine if the procedure has any long-term adverse effects on knee function.

Research compiled and edited by Barbara J. Fister

AUDIENCE INQUIRY

For general information on wrist fractures:

American Academy of Orthopaedic Surgeons, orthoinfo.aaos.org

American Society for Surgery of the Hand, assh.org

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