NEW YORK (Reuters Health) - Patches that deliver nitroglycerin through the skin do nothing to help speed healing from a common type of injury to the Achilles tendon, UK researchers have found.
Noninsertional Achilles tendinopathy is a tear in the tendon above the point where it inserts into the heel bone. The cause of the condition hasn't been established, although overuse may be a factor in some cases, Dr. Timothy P.C. Kane, of North Hampshire Hospital in Basingstoke, and colleagues write in the American Journal of Sports Medicine.
There is little scientific evidence to support the many different approaches to treating the condition, the researchers add, although a previous study found that topical glyceryl trinitrate (GTN), in the form of the Nitroderm patch made by Schering-Plough, improved outcomes.
The authors of that study suggested that the patches -- which are normally used to treat chest pain called angina -- may have aided Achilles tendon injuries by increasing the formation of collagen and stimulating the activity of fibroblasts, the cells responsible for making connective tissue.
To investigate further, Kane and his team randomly assigned 40 patients with noninsertional Achilles tendinopathy to receive either standard physical therapy or standard physical therapy plus a daily GTN patch for six months. Patients who didn't improve underwent surgery, at which time the researchers sampled tissue from the tendon.
There was no difference in pain or disability scores between the two groups after six months, the researchers found. And examination of tissue in those who underwent surgery found no difference in new blood vessel growth, collagen synthesis or fibroblast activity.
The findings, according to Kane's team, suggest that the nitroglycerin patch will not help people with noninsertional Achilles tendinopathy heal any faster.
SOURCE: American Journal of Sports Medicine, June 2008.
