The radius is the forearm bone that connects to the thumb-side of the wrist. If you break this bone where it joins the wrist, there are a few ways to treat your injury. External fixation is one of them. Surgeons use an external fixator to hold the bones in place from the outside using special pins. One type of fixator keeps the wrist from moving. Another, called a dynamic fixator, allows you to move your wrist right after surgery. Once the bones have healed, the pins and device are removed.
These authors prefer a dynamic fixator, so their patients can begin working on wrist mobility soon after surgery. However, this treatment may not stabilize the wrist enough for it to heal properly. A bone graft may have to be implanted to join the broken bones together. Rather than using bone from the patients’ own body, which can lead to other complications, these authors experimented with a bone substitute called hydroxyapatite (HA).
Twenty-five patients participated in the study. Fifteen were women; 10 were men. Their ages ranged from 19 to 75, with an average of 49. Most of the patients had injured their wrists in a fall.
During surgery, patients were placed in the external fixator; they also had a block of HA implanted at the fracture site. Small pieces of HA were used to fill the space between the block and surrounding bone. Wrist and hand movement was encouraged soon after surgery. At six weeks, the pins were removed. Patients were followed up two to four years after surgery (average = 2.5 years).
At follow-up, patients’ wrists showed good range of motion in all directions. For patients who injured their dominant hand, grip strength recovered to 89 percent of that of the other hand. For patients whose nondominant hand was involved, grip strength recovered to 73 percent. All but one of the wrists were classified as “excellent.” The remaining wrist was “good.”
X-rays showed that the block of HA healed to the surrounding bone within two to three months of surgery. In general, the alignment of bones after surgery was good. There were no complications from surgery, and no patients showed signs of arthritis.
The authors suggest that HA has several advantages over bone from the patient’s body. To use patients’ own bone, a second part of the body has to be operated on. This brings the risk of infection, pain fracture, or nerve injury. HA works well as a substitute. It is better able to bond with bone than bone cement. Even older patients with osteoporosis had good results from the HA block plus external fixation.
Inserting small pieces of HA around the block made healing happen three months faster than using the HA block alone. Getting the bones and joints to line up also made a big difference in helping people get back to their normal activities.