The vast majority of shoulder replacement surgeries are successful. However, complications can occur even when surgeries are done properly and go smoothly.
Below is a list of potential complications. In rare instances, some complications are life-threatening. A small percentage of patients will require a second, or revision, surgery.
Complications Involving Anesthesia
Any major surgery involving general anesthesia has a low risk of strokes, heart attacks, pneumonia, and blood clots. Blood clots occurring in deep veins, called deep vein thrombosis (DVT), are of particular concern following joint replacement surgeries, but this complication is more common in lower extremity replacements than upper extremity replacements.
If left untreated, a blood clot can break free from the vein wall, resulting in a life-threatening condition known as pulmonary embolism. When caught in time, pulmonary embolism is treatable with anti-clotting medication.
Antibiotics are routinely given at the time of surgery to reduce the risk of infection. Despite this precaution and other measures, superficial and deep wound infections affect a small percentage of shoulder replacement patients. Most of these patients can be treated with antibiotics.
In rare cases, an infection may result in the removal of the artificial shoulder joint and can even be life-threatening. After the infection resolves, it may be possible to surgically implant a new prosthetic.
Aside from risks associated with anesthesia and infection, there are potential complications specific to traditional shoulder replacement surgery:
Rotator cuff damage
The rotator cuff muscles are more prone to injury following surgery. To decrease the risk to the rotator cuff problems:
- Prior to surgery, a surgeon will carefully evaluate the rotator cuff muscles for damage that might be made worse by a traditional shoulder replacement.
- During surgery, a surgeon will make all efforts to minimize soft tissue damage.
- After surgery, the patient must learn how and when to keep the shoulder immobilized and supported. The patient must also learn what movements are safe and what movements pose a risk to the healing shoulder.
Prosthetic misalignment or loosening
Total shoulder replacement surgery is a complicated manipulation of the patient's native bone, prosthetics, and soft tissue. If a prosthetic is not sufficiently secured into the native bone, or if it is not well-aligned with other parts of the shoulder, problems can occur.
Of particular concern are loosening and alignment problems with the socket, or glenoid component. Patients with prosthetic loosening do not always feel symptoms. Those who do feel symptoms may have shoulder pain and/or stiffness. Prosthetic loosening can result in other problems, such as joint instability, which can affect the shoulder's range of motion and function.
The patient's bone of the humerus or glenoid can break during or after surgery. A patient's risk of fracture can be affected by the patient's anatomy and bone density as well as the surgical placement of the prosthetics. A post-surgical fracture may require a second surgery.
Joint dislocation or partial dislocation (subluxation)
The new shoulder may dislocate from the new socket, or glenoid. This risk decreases as the muscles around the shoulder joint are strengthened through physical therapy.
Blood vessel or nerve injury
The surrounding nerves and blood vessels can be injured during surgery, though this risk is low. Experts estimate anywhere between 0.6 and 4.3% of patients experience some nerve injury following shoulder replacement surgery, though 80 to 85% of those cases resolve on their own.3-8
In rare cases, a patient has an allergic reaction to the bone cement or joint prostheses. In these cases the bone cement and prostheses must be removed.
Most complications can be successfully treated. A surgery followed by complications may still be considered successful if pain is alleviated and function improves over the long term.
A patient can reduce the risk of complications by working with an experienced surgeon. Some studies have shown that complication rates are lower for surgeons and hospitals that do a lot of shoulder replacements.9-11
Revision Surgery for Total Shoulder Replacement
If the artificial shoulder joint wears out or otherwise fails, a surgeon may recommend a revision surgery to remove and replace the joint prostheses. Revision surgeries are often elective, meaning the patient can take time to decide whether to undergo another surgery. Rare but notable exceptions are infection and dislocations.
Shoulder revision surgeries are more complex than initial replacement surgeries, and carry a higher rate of risks and side effects.
Revision surgery for total shoulder replacements is more common for patients under age 60 men, and patients who have rotator cuff disease.