Medical research continues to show that injecting steroids into shoulder tendons is a bad idea. The most common shoulder injection is a combination of a steroid and an anesthetic. The type of steroid is called corticosteroid because of its anti-inflammatory effects. Not much has really changed in the world of steroid injections since the 1950s when the Upjohn drug Cortisone first was sold. Being offered a steroid injection for shoulder pain should give a patient pause. The therapy has been around more than 60 years and dates to the time when lobotomy was all the rage in treating mental illness.

It’s long been known that steroids harm tissue. There are more than 62,000 research papers on corticosteroid side effects. The first paper about the side effects of steroids used to treat arthritis was published in 1951. The first inkling that steroids could harm soft tissues was in the 1960s.

Why are steroids so bad for tissue? First, the dose of steroids never was determined by studying the effects of the substance on human cartilage, tendon, or muscle. Instead, steroid dose was calculated by observing how much of the drug needed to be given intravenously in order help diseases such as asthma. If the amount of steroids that a normal tendon would be exposed to when produced by the body to control swelling were represented by the height of a matchbook, the amount that doctors inject into shoulder tendons would be the height of the Empire State Building. The second issue is the direct effects of steroids on tissue. All bones, tendons, muscles, and cartilage have reserve cells inside them, called stem or progenitor cells. These are there to help maintain cells that die off due to normal wear and tear. A number of studies have shown that steroids at high doses hurt these cells, leaving the tissue without any ability to repair or maintain itself for many months.

Research reported in the February 2015 issue of International Orthopaedics focused on the effects of steroids on the tendons of patients undergoing rotator cuff surgery. The original goal of the study was to map the amount and density of blood vessels in different parts of the shoulder rotator cuff tendons. This is important because recent studies have shown that rotator cuff tears don’t heal well when the tendon has developed fewer blood vessels and has poor blood supply. While the study in International Orthopaedics showed a pattern of blood vessels that might be helpful to surgeons, the most startling finding was that patients who had shoulder steroid shots before the surgery had one-third fewer blood vessels than the patients who didn’t receive the shots.

Steroid injections are bad news. Study after study continues to show that they damage tissue at a cellular level, with this most recent research showing steroids decrease the blood supply critical for healthy tissue. Because steroid shots are covered by insurance, they’re the most common injection for orthopedic pain.

“More Bad News About Shoulder Steroid Shots” first appeared as a post on the Regenexx blog.