What is a hemiarthroplasty of the shoulder?
A hemiarthroplasty of the shoulder involves the replacement of the ball (humeral head) with the prosthesis, and the socket (glenoid) is left intact.
A hemiarthroplasty is a surgical procedure that replaces one half of the shoulder joint.
The shoulder is made up of three bones: the upper arm bone (humerus), shoulder blade (scapula), and the collarbone (clavicle). The shoulder joint is a ball-and-socket joint—the ball or head of the humerus fits into a shallow socket known as glenoid in the shoulder blade. Surrounding the joint is a layer of articular cartilage that acts as a lubricant reducing abrasion of the bones.
A hemiarthroplasty of the shoulder involves the replacement of the ball (humeral head) with the prosthesis, and the socket (glenoid) is left intact.
Why is a shoulder hemiarthroplasty done?
Shoulder pain and disability can be intimidating and may not be cured by medications or physical activities alone. In such cases, a shoulder hemiarthroplasty is preferred. Several conditions can cause joint pain and disability:
- Osteoarthritis of the shoulder (a degenerative joint disease)
- Rheumatoid arthritis of the shoulder (inflammation of the membrane surrounding the joints)
- Shoulder injury
- Avascular necrosis (disruption of the blood supply to the shoulder joints)
- Severe fractures
- Failed previous shoulder replacement surgery
- Loss of motion or weakness in the surgery
- Failure of other treatments such as anti-inflammatory medications, cortisone injections or physical therapy
- Rotator cuff tear arthropathy (wear and tear of the shoulder joints caused over time due to damage of the rotator cuff muscle)
- Tumors of the shoulder
When should a shoulder hemiarthroplasty be avoided?
A shoulder hemiarthroplasty should be avoided in the following conditions:
- Infections
- Neuropathic shoulder (nerve damage of the shoulder)
- Ankylosed shoulder (joint stiffness due to abnormal fusion of the joint bones)
- Previous glenohumeral arthrodesis (abnormal fusion of the glenoid and humeral head)
- Incompatible glenoid and humeral surfaces
- Fractures treatable with open reduction and internal fixation surgery
- Less severe fractures treatable nonoperatively
- Unenthusiastic patient
- Poor general health
- Deltoid paralysis (paralysis of the deltoid muscle in the shoulder)
- Unrealistic patient goals
How is a shoulder hemiarthroplasty performed?
A shoulder hemiarthroplasty should be performed under general anesthesia. The physician makes an incision in the area between the upper arm and shoulder. Next, the physician rotates or extends the arm to locate the humeral head. Before cutting out the humeral head, the surrounding muscles and tissues connecting the muscle and bone (tendons) are protected.
Once the surgeon locates the humeral head, an instrument called an osteotome is used to cut the humeral head. The surgeon then replaces it with a cap-like prosthesis. The incision is then closed with stitches.
What to expect after a shoulder hemiarthroplasty surgery?
You need to perform exercises to prevent joint stiffness. You can return to the normal routine after 24 weeks of strengthening exercises.
The healing takes place in phases:
- Phase I: You will remain in a shoulder immobilizer for four weeks. During this time, you need to perform pendulum motion.
- Phase II: After four weeks, the sling will be removed so that you can use the arm for daily activities.
- Phase III: At eight weeks, therapy consists of advanced strengthening exercises.
- Phase IV: At 16 weeks, you can practice skilled sports.