A New Look at Why Shoulder Replacement Doesn’t Work Well in Younger Adults

Orthopedic surgeons are likely to suggest patients delay total shoulder replacement (TSR) based on age. Studies show that patients who are 50 and younger just don’t have as good of results as patients over 50 with this procedure. But this study brings new data that suggests maybe we are barking up the wrong tree. It’s not age that’s the determining factor but rather, the cause of the problem!

It turns out that younger patients with shoulder pain and loss of function severe enough to warrant replacing the joint is more often due to capsulorrhaphy arthropathy than degenerative joint disease. Capsulorraphy arthropathy refers to arthritis that occurs after a previous surgery on the shoulder. That surgery might have been to repair a torn rotator cuff or relocate a dislocated shoulder. Degenerative joint disease is age-related osteoarthritis more common in older adults.

In order to come to this conclusion, surgeons from the Department of Orthopedics and Sports Medicine at the University of Washington in Seattle took a look at the results of over 1000 patients treated with shoulder replacements. The procedures were all done by one surgeon over a period of 10 years. It’s common knowledge from many other studies that outcomes are different based on age. The researchers involved in this study knew from other studies that there have been numerous reasons proposed for these differences.

For example, maybe the younger patients went into the surgery with worse shoulder function compared with older adults and that made a difference in their final results. Some studies showed that women tend to report worse outcomes than men. Perhaps women just have a different idea of what is a successful surgery compared with men. Younger patients seem to have more complex pathologies (e.g., loss of blood to the joint, post-traumatic arthritis) compared with older adults. The vast majority of older adults who need a shoulder replacement suffer from osteoarthritis. These three potential causes for poor performance after total shoulder replacement (gender, level of perceived disability, and diagnosis) were the focus of this study.

So, which is it? Well, we spilled the beans right away by telling you it was the cause of the problem that was statistically linked to outcomes. There wasn’t a significant difference in results based on sex (male versus female) in either age group or comparing one age group to the other. The idea that maybe how the patient views his or her level of disability was a contributing factor didn’t pan out either. Patients on either side of the age of 50 (younger or older) tested out the same when given tests to self-assess disability.

The more complex pathologic problems suffered by younger patients appear to be the missing link. Levels of pain, discomfort, and function leading to patient dissatisfaction were more commonly reported in the younger folks. And that makes sense when taking into account the greater involvement of the surrounding soft tissues with capsulorraphy arthropathy that complicate the surgery and follow-up rehab program.

The authors do say that this was just one study looking at the patients of one surgeon. They didn’t look at all possible variables and factors. They focused on just the three mentioned. There are lots of ways adults with severe shoulder disability who are under 50 differ from adults with similar problems who are over 50. Even the surgical procedures could make a difference. Not everyone has the same operation or gets the same implant — even if the same surgeon does all the operations.

And let’s not forget the fact that younger patients are often much more active than older adults. The activity level alone could increase the risk of problems like implant loosening or debris collecting inside the implant from wear and tear. The authors also suggested it’s possible that younger adults have higher expectations so they rate their results lower than older adults would with the same results. And finally, younger adults have a longer period of time during which the implant can malfunction, deform, or create problems.

All in all, we really don’t have all the answers as to why younger adults don’t do as well as older adults after shoulder replacement surgery. But this study at least raises a few more questions and offers some evidence that the age factor may not be the real reason for differences in perceived outcomes. Further study and analysis like this one will help clear up this issue in time. Until then, each surgeon must make the best decision possible based on current evidence and individual patient differences and expectations. This should include age as well as other factors. Younger patients must be counseled as to the potential problems they may face postoperatively based on current research findings.