There have been a bevy of studies this past year on how patients who get steroid injections for tennis elbow and plantar fasciitis are worse in the long-term. While these steroid shots are a mainstay of treatment, they are also very hard on tissue. It’s therefore no surprise that a new study just published continues this trend by showing that shoulder steroid injections are bad for the tendon.
The new study looked at patients who had a shoulder rotator cuff tendon surgery versus those who had shoulder steroid injection. The researchers were interested in a number of properties of the rotator cuff tendon after the procedures. They used rotator cuff surgery as a control because they wanted a bench mark of a healing shoulder tendon when examined using multiple cellular probes.
After taking small tendon biopsies, they looked at the health of the tenocytes (the cells that make up a tendon). First, the healing rotator cuff tendon samples showed what you would expect to see with healing – more cells and blood vessels. However, the shoulder steroid injection group had neither. Other indicators of healing (cell proliferation and HIF-1A) were present in the shoulder surgery group and not the shoulder steroid injection patients. In addition, an important cell receptor linked to cell death and poor cell health (NMDAR1) was more prevalent in the shoulder steroid injection group. This same receptor is also found to be increased in severe alcoholics whose cells are being poisoned by the alcohol. Finally, while evidence of painful inflammation was present in both patient groups (increase in the neuro excitation agent glutamate), the steroid injection patients weren’t expressing the off switch for that pain while the healing rotator cuff group was expressing this receptor (metabotropic glutamate receptor 7). This may help explain why tennis elbow patients who are injected with steroids have more pain in a few months – the switch for normal healing pain is left stuck in the “On” position by the steroids!
The upshot? Based on this and many other studies, steroids are bad news for tendons. Despite this, they are still widely used. Please get the word out that in 2014, injecting a 1950’s solution into your tendons is no longer acceptable!