Many of the “key joints” in your body are designed to allow for smooth, consistent movements. Some of these joints, like ones in your knees, shoulders, and hips, also play an important role in mobility and the ability enjoy favorite activities. But when a joint is affected by problems such as arthritis or a fracture (broken bone), it may eventually need to be replaced.
While some situations do require replacement of the entire joint (total joint replacement), there are instances where it may be better to replace only half of the joint. This is referred to as a hemi joint replacement.
What Is a Hemiarthroplasty?
Arthroplasty is the term for joint replacement. Since “hemi” means half, a hemiarthroplasty is replacement of half of a joint. The half of the joint that’s replaced with artificial parts will depend on what part of the joint is damaged. With ball-and-socket joints in shoulders and hips, it’s often the “ball” part that’s replaced since it’s usually more susceptible to wear-and-tear and stress from movements. Other types of joints may also be “half replaced,” including ones in elbows and wrists. In feet, it’s often the big toe joint that’s replaced in this way.
Who Is a Good Candidate for a Hemi Joint Replacement?
Typically, hemi joint replacements are recommended for younger, healthy patients, including those who are routinely active and prefer to retain as much joint flexibility as possible. In some instances, older patients unable to go through a more extensive type of joint replacement surgery might benefit from a hemiarthroplasty. Hemi joint replacement may also be recommended if it’s likely that a total joint replacement would fail over time because of related soft tissue damage or other possible sources of instability.
How Is Surgery Performed?
As with a total joint replacement, parts used for a hemiarthroplasty come in various shapes and sizes. They are usually made of a combination of plastic materials and durable metal alloys. Prior to surgery, tests are performed to evaluate the joint in detail. This process may include a visual examination of the affected joint with an arthroscopy, a technique involving the insertion of a small, lighted tube into into the joint to determine the extent of the damage.
An arthroscopy can also identify any pieces of bone or cartilage that may need to be removed. During the operation, the damaged part of the joint is removed. The new components are then inserted. With ball-and-socket joints, the new part may be wedged tightly into place or cemented. In addition to cementing, surgical screws and other types of hardware may be used with other types of joints.
How Might Patients Benefit from a Hemiarthroplasty?
The advantages of a hemi joint replacement over other options include the use of less-invasive techniques and the fact that part of the original joint is preserved. Also, since the entire joint isn’t being removed, there’s often a reduced risk of damage to supporting tendons, ligaments, and muscles. Patients may also benefit from:
- A shorter recovery period
- Restoration of full joint flexibility and range of motion
- Less post-surgery discomfort
The main risk associated with a hemi joint replacement is the possibility that the other half of the joint may eventually need to be replaced. However, if steps are taken to help maintain optimal joint health, such as eating foods with nutrients good for bones, taking proper precautions when playing sports, and minimizing issues with underlying conditions that can affect joints like arthritis and diabetes, there may be less risk of experiencing further problems with a joint after a hemiarthroplasty.