Easy does it after shoulder steroid shot

NEW YORK (Reuters Health) - New research hints that people with rotator cuff injury who enjoy rapid pain relief following a steroid injection should not immediately return to vigorous activity or start physical therapy right away, even if they feel remarkably better.

According to a study reported this week at the Orthopedic Research Society meeting in San Diego, steroid shots temporarily produce changes in the tendon that mimic that of a tendon injury, possibly making the tendon more vulnerable to damage during this time. [inter/pr]

"Our results suggest that perhaps strenuous activity or strenuous physical therapy immediately following a steroid injection might not be a good idea," Dr. John Callaci from Loyola University Chicago Stritch School of Medicine, Maywood, Illinois, told Reuters Health. [inter]

"A patient may get a steroid injection and feel great, but maybe they should be careful for a period after that injection." [inter]

In an earlier study, Callaci and colleagues found that when steroid is injected into an uninjured rat rotator cuff tendon, there is a marked change in collagen gene expression, which mimics what happens after a tendon is injured. [inter]

Based on this observation, the team used gene array technology, which looks not just at a couple of genes but at thousands of genes simultaneously, to study the tissue response of rat rotator cuff tendon to induced injury and steroid injection. [inter]

They found that 2,000 genes were changed by tendon injury and 1,000 genes were changed by steroid injection. [inter]

What's interesting, Callaci said, was that there was some significant overlap in the genes that are modulated by injury and the genes that are modulated by steroids. [inter]

"This suggests," he explained, "that there may be some things going on, at least temporarily, in the tendon after a steroid injection that looks like what is going on after a tendon is injured." Thus, there may be a temporary period of vulnerability or weakness in a tendon after a shot of steroid. [inter]

"If a patient returns to rigorous activities right after a steroid injection, the weakened tissue may not be able to sustain itself," he said. [inter]

The Loyola team is currently conducting a biomechanical study to test whether these tendons are in fact weaker after steroid injection than control tendons. "This is really important to find out," Callaci said, adding that he hopes to have an answer in 3 to 4 months. [inter]