Study Design for A Prospective Comparative Analysis on the Outcomes and Complications of Ultrasound Guided Corticosteroid Injection on Tendinopathy in the Foot and Ankle

Christopher H. Merritt, MS; Benjamin D. Kennedy, J. Benjamin Jackson III, MD

Corticosteroid injections (CSI) are widely used with the average orthopedic physician performing 20.6 injections per month.  CSI are used to treat tendinopathy due to the anti-inflammatory properties that corticosteroids possess.  An ultrasound-guide is used to place the CSI into the tendon sheath and not the tendon itself.  The injection mixture typically contains a corticosteroid and an anesthetic.  The most common corticosteroids used are triamcinolone acetonide or methylprednisolone acetate, with the typical anesthetic being lidocaine.  Despite how common CSI are in the clinical environment, the clinical evidenced based data to support corticosteroid injections in tendinopathy is lacking. There is evidence showing corticosteroids increase tendon damage, therefore increasing risk of tendon rupture.  Corticosteroids decrease type I collagen and the proteoglycan decorin, both crucial for the structural integrity of the tendon.  Given the volume of these injections performed, even if tendon rupture is rare, it represents an important complication that needs to be studied further.  Not only is corticosteroid injections literature lacking regarding tendon rupture, but there is a lack of information concerning other complications as well.  The other complications included are nerve damage, cartilage damage, and thinning of skin around the injection site.  Occurrence of surgery on the effected tendon(s) will be measured along with patient reported complications related to the injection area.  Injections with or without an ultrasound guide will also be measured.  With current literature reporting corticosteroid injections decrease both collagen and decorin, we expect to see reported occurrences of tendon rupture along with reports of the other side effects.