My friends tell me not to be surprised when I see the orthopedic surgeon about a shoulder replacement because there are many and varied implants to choose from. I guess there isn't just one-size-fits-all or even one replacement type for everyone. What can you tell me ahead of time to help prepare me?
Back in the 1970s, there was only one prosthetic implant available for patient's needing a total shoulder replacement (TSR). Today, there are more than 70 different shoulder systems on the market.
Even though there are dozens and dozens to choose from, surgeons tend to pick between one of three main types of arthroplasty (another name for shoulder replacement). There's the hemiarthroplasty (only one side of the joint is replaced), the reverse total shoulder arthroplasty (RTSA), and the total shoulder replacement (TSR) already mentioned.
the hemiarthroplasty. This is just the replacement of the humeral head and upper neck of the humeral bone supporting the head. At first, these were designed for people with humeral neck fractures. But the use of the hemiarthroplasty has expanded over time as surgeons found other problems that were solved with this component. Now it is also used for arthritis, rotator cuff tears, and osteonecrosis (bone death caused by loss of blood supply) of the humeral head.
Studies show that the hemiarthroplasty is more likely to be successful when used in younger patients and early after the injury (in other words, without a long delay between injury and operation). Sometimes it's just difficult to decide between the hemiarthroplasty and a full shoulder replacement. Why do a full replacement when a partial replacement would work just as well? But there's no sense in doing a partial replacement if the patient is going to end up needing a full shoulder replacement eventually anyway.
The most reasonable use of the hemiarthroplasty is for the patient who has bone loss and soft tissue damage that makes surgical reconstruction a very complex project. Without adequate bone mass and sufficient muscle strength, the implant loosens, which can lead to implant failure. Hemiarthroplasty offers a way around those complications.
It's most effective when the shoulder socket is perfectly fine but the head of the humerus is arthritic, damaged from osteonecrosis or rotator cuff tears, or defective. Patients who receive a hemiarthroplasty report it is certainly better than doing nothing -- they get pain relief, increased motion, and improved function. The net result is an improved quality of life.
It's also possible to resurface the joint when arthritis has damaged the joint surface but there's no need to tear the whole thing out and replace it. This procedure is called a resurfacing hemiarthroplasty. The humeral head is smoothed but not removed. Sparing the humeral side also preserves the patient's natural joint angles. If there's a need for a total shoulder replacement later, then it can be done sometime down the road. Shoulder resurfacing is used most often in young (55 years old or younger), active/athletic adults.
A reverse shoulder arthroplasty is used in older adults who have a torn rotator cuff that can't be repaired. Instead of the round ball replacing the head of the humerus (upper arm bone), the socket is attached to the bone. The round replacement ball of the joint (called the glenosphere) is inserted into the place where the natural shoulder socket used to be.
This design helps maintain shoulder stability when the muscles are deficient and unable to function as they should. In fact, many patients who suffer pseudoparesis (inability to lift the arm) benefit from a reverse shoulder arthroplasty. The change in the fulcrum allows them to lever the arm up even when the muscles are weak from irreparable injury or damage.
When both sides of the joint are involved, it makes the most sense to perform a total shoulder replacement. Loss of joint cartilage from arthritis leading to pain and disability are the main reasons to do a full joint replacement. The rotator cuff must be in good condition to support the joint and restore full function of the shoulder and arm. And there has to be enough good bone stock to support and hold the implant in place.
Many, many studies have shown the benefit of the total shoulder replacement (TSR). Compared with the other options, the TSR gives patients more motion, less pain, and improved strength. Regardless of where the erosion occurs in the joint or what causes it (osteoarthritis versus inflammatory arthritis), the complete replacement of both sides solves the problem.
J. Michael Wiater, MD, and Meredith H. Fabing, DO. Shoulder Arthroplasty: Prosthetic Options and Indications. In Journal of the American Academy of Orthopaedic Surgeons. July 2009. Vol. 17. No. 7. Pp. 415-425.
*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.