Wrist replacement surgery may help retain or recover wrist movements. It may also improve the ability to perform daily living activities, especially if there is arthritis in the elbow and shoulder. During any total joint replacement, the worn-out ends of the bones are removed and replaced by an artificial joint (prosthesis).
In some cases, fusing the bones of the wrist together will reduce or eliminate pain and improve grip strength. However, if the bones are fused together, the wrist will not be able to bend .
There are several different types of implants. Most have two components, one for each side of the joint. These components are made of metal.
A high-quality plastic, called polyethylene, is used as a spacer between the two metal components. Newer implant designs try to replicate the anatomy of the wrist.
One component is inserted into the radius of the forearm. The portion of this component that faces into the wrist joint has a curve that fits a second component placed on the wrist side. The component that inserts into the hand bone (the carpal component) has a flat surface that faces the first component. It inserts into a carpal bone through one long stem and one or two shorter stems.
A plastic spacer fits between the components in the joint area.Spacers come in different sizes so they can match the hand. A spacer is normally flat on one side and rounded on the other. This design enables it to fit into the carpal component while it rocks on the radial component, creating a more natural wrist motion.
Wrist joint replacement can be done as an outpatient procedure, unlike a hip or knee replacement. Wrist replacement surgery is often combined with other procedures to correct deformities or disorders in the tendons, nerves, and small joints of the fingers, and thumb.
An incision is made on the back of the wrist. The damaged ends of the lower arm bones are removed and the first row of carpal bones may also be removed. The radial component of the prosthesis is inserted into the center of the radius bone on the outside of the lower arm. It is held in place with bone cement.
Depending on the component design, the carpal component is then inserted into the center hand bone (third metacarpal) or screwed into the remaining row of carpal bones. Bone cement may be used to hold the component in place. The carpal bones may be linked or fused together to better secure this component.
An appropriately sized spacer is used between the metal components to complete the procedure.