The rate of reverse shoulder arthroplasties (RSA) is increasing as its indications are expanding, but various reports suggest that these procedures are associated with a high complication rate. “Research has shown that several comorbidities can increase the risk of infection in orthopedic surgeries, including diabetes, smoking, morbid obesity, and rheumatoid arthritis,” explains Brent J. Morris, MD. Although several small studies have been conducted, few analyses have examined a large series of patients and controlled for confounding factors to confirm which variables are risk factors for infection after RSA. To address this research gap, Dr. Morris and colleagues had a study published in the Journal of Should & Elbow Surgery to explore risk factors for periprosthetic infection after RSA.
Identifying Risk Factors
For the study, the investigators reviewed 301 primary RSAs with a minimum of 1-year follow-up in a prospectively collected shoulder arthroplasty registry. Overall, about 5% of the study group experienced periprosthetic infections after RSA, a finding that was similar to what has been seen in previous studies. “A failed prior arthroplasty was identified as an independent risk factor for infection after RSA,” says Dr. Morris. “We also found that age appeared to be an important consideration. Patients younger than 65 were at greater risk for infection after RSA. It’s possible that prior shoulder surgery increases risks for infection because of unrecognized indolent infections.” Prior surgery can also create a large amount of dead space that may predispose these patients to infections.
The analysis also examined the effect of patient comorbidities on risk of infection after RSA. According to the findings, a history of smoking, diabetes, rheumatoid arthritis, or obesity did not appear to contribute to a higher risk of infection after these procedures, but a larger series of patients may be needed to confirm this data. Notably, the analysis included 42 patients who had rheumatoid arthritis, but these patients were not at greater risk for infection when controlling for other variables. Similar findings were observed among diabetics, smokers, and those who were severely obese.
Dr. Morris says his study team’s analysis is among the first to report on risk factors for infection after RSA while controlling for confounding variables. “The procedure has only been available for a little over a decade in the United States, so it’s still relatively new,” he says. “Our study findings may enable clinicians to better counsel patients about risk factors for infection before their operation.” He adds that in light of the challenges associated with treating periprosthetic infection after RSA, more research is needed to better stratify patients who are at a higher risk for development of infection after RSA.
Morris BJ, O’Connor DP, Torres D, Elkousy HA, Gartsman GM, Edwards TB. Risk factors for periprosthetic infection after reverse shoulder arthroplasty. J Shoulder Elbow Surg. 2015;24:161-168. Available at: http://www.jshoulderelbow.org/article/S1058-2746(14)00281-X/abstract.
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