Effect of steroid injections on the rotator cuff: an experimental study in rats

J Shoulder Elbow Surg. May-Jun 1999;8(3):271-4. doi: 10.1016/s1058-2746(99)90141-6.


The aim of this study was to evaluate the effects of repeated steroid injections into the subacromial space. Thirty rats were injected either 3 or 5 times with triamcinolone in a dosage equivalent to that given to human beings or 3 or 5 times with saline into the subacromial space. One rat received no injection. The supraspinatus and infraspinatus tendons were evaluated macroscopically and microscopically. Two different staining methods were used on each sample including hematoxylin eosin and Miller's elastin/van Gieson's solution. After 5 steroid injections, we found focal inflammation, necrosis, and fragmentation of collagen bundles in the tendon in 4 of 7 rats. The tendons of the controls showed a normal structure (P < .05). There were no pathologic changes among the rats that were injected with triamcinolone 3 times. These results show that repeated subacromial injections of triamcinolone may cause damage to the rotator cuff of the rat. This finding may indicate cautious use of subacromial steroid injections in human beings.

MeSH terms

  • Animals
  • Anti-Inflammatory Agents / administration & dosage
  • Anti-Inflammatory Agents / adverse effects*
  • Female
  • Joint Diseases / complications
  • Pain / drug therapy
  • Rats
  • Rats, Sprague-Dawley
  • Rotator Cuff / drug effects
  • Rotator Cuff / pathology*
  • Shoulder Joint / pathology
  • Tendons / drug effects
  • Tendons / pathology
  • Triamcinolone / administration & dosage
  • Triamcinolone / adverse effects*


  • Anti-Inflammatory Agents
  • Triamcinolone