Houston Methodist. Leading Medicine

Shoulder FAQ


I had a shoulder replacement done that came undone. The socket side just loosened and started shifting around. How often does this happen and why does it happen?


Total shoulder replacements are much newer compared with hip or knee replacements. Instead of the hundreds of thousands of these implants (like hips and knees) being done, there are only about 25,000 shoulder replacements done each year in the United States. Problems and the need for revision (a second) surgery are much more common with shoulder replacements. In fact, up to seven per cent of patients receiving their first shoulder replacement will end up with a second surgery for one reason or another. The most common reason for implant failure is malposition of the glenoid component. That's the socket or cup-side of the joint. Even a small amount of twist off-center can cause uneven load, force, and wear. Surgeons are often faced with complex challenges when the reason the patient developed severe shoulder osteoarthritis was because of a natural off-angle in the shoulder. That deformity must be corrected before inserting the new implant. And getting a perfectly shaped socket that matches the new implant can take extreme technical expertise on the part of the surgeon. Post-operative loosening, malunion, or failure for any other reason may be the result of the type of surgery used to reshape the socket first before putting the implant in place. Making the selection of the "best" procedure for each patient requires considerable preoperative planning. The surgeon evaluates the strength of your bone, studies any deformities that might be present, and calculates which technique (or combination of techniques) will be best for you. Three-dimensional (3-D) CT scans with software that helps the surgeon plan the reconstruction can help reduce the risk of failure. Sometimes there isn't a clear reason why an implant loosens or failures to take hold. Even minor defects in the joint shape and/or surface can make a difference. There are always limits to what can be done to create a perfect result. And even when everything looks perfect, implant failure can still occur. Benjamin W. Sears, MD, et al. Glenoid Bone Loss in Primary Total Shoulder Arthroplasty. In Journal of the American Academy of Orthopaedic Surgeons. September 2012. Vol. 20. No. 9. Pp. 604-613.

*Disclaimer:* The information contained herein is compiled from a variety of sources. It may not be complete or timely. It does not cover all diseases, physical conditions, ailments or treatments. The information should NOT be used in place of visit with your healthcare provider, nor should you disregard the advice of your health care provider because of any information you read in this topic.
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