The humerus head is the ball at the top of the upper arm bone that fits into the shoulder socket. Severe fractures or degradation of the ball head due to chronic conditions may require replacement of the head. In those cases, a surgical procedure called hemiarthroplasty is used. 

Treatment and Recovery

The humeral head may need replacement in cases of severe fracture or damage from avascular necrosis, which is when the humeral head is compromised by poor circulation. Treatments such as injections and physical therapy are often used to relieve avascular necrosis, but if they fail, hemiarthroplasty can be used to repair the joint.

In this surgery, the humeral head is replaced with a prosthesis, leaving the glenoid (shoulder socket) intact. The surgery usually takes 1-2 hours and will require an overnight hospital stay. 

Patients will need to wear a sling for 3-5 weeks while the joint heals. Physical therapy will be necessary to return a proper range of motion to the shoulder. Patients can expect range-of-motion and strength recovery to take several months. 

Most patients report pain and stiffness relieved by this surgery. Complications are rare but can include shoulder stiffness, instability, infection, and nerve damage.