The study was presented today at the American Academy of Orthopaedic Surgeons annual meeting in Chicago by Theodore Blaine, M.D., assistant professor of orthopaedic surgery at Columbia University Medical Center and an attending surgeon at NewYork-Presbyterian Hospital.
The study showed that in patients with osteoarthritis of the shoulder, sodium hyaluronate was effective in reducing chronic pain by nearly 50 percent. The results were comparable to the 1998 study that led the FDA to approve the drug's use in treating knee pain. The FDA is currently reviewing the results in shoulder pain.
"Chronic shoulder pain is a common problem that can not adequately be treated with existing FDA-approved therapies," said Dr. Blaine, who was the principal investigator of the study. "The results of the trial were very encouraging, and we hope will lead to this drug's approval as an effective therapy for thousands of suffering patients."
According to the National Institute of Musculoskeletal and Skin Diseases, shoulder problems account for about 1.5 million visits to orthopaedic surgeons annually. The pain can be caused by a variety of problems, including osteoarthritis or rotator cuff tears.
Sodium hyaluronate is a vital building block of normal cartilage. It is marketed under the name Hyalgan by Sanofi Aventis.
All of the patients in the study had previously tried nonsurgical clinical interventions - including physical therapy, at least one steroid injection, and various oral pain medications - but the pain persisted. At the beginning of the study patients received an x-ray of the shoulder to confirm the diagnosis of osteoarthritis and rule out fractures or other exclusionary criteria, as well as an MRI to diagnose soft tissue and bony pathology or a tear in the rotator cuff.
The 602 patients who comprised the study population were broken up into three groups. One group received five injections of the drug over six months. A second group received three injections, followed by two saline injections, and the third group received just a placebo of five saline injections.
Throughout the six month trial, the patients were asked to record their level of pain on a scale of one to 100 -- with 100 being the worst pain imaginable. All three groups began with an average baseline score of 65. Patients with osteoarthritis who received sodium hyaluronate saw the greatest decrease in their pain scores, which was reduced to a score of 35 in six months. The patients who received three injections ended up with a pain score of around 37.
The patients who received saline also saw a decrease, to around 43. The improvement in the saline group could be the result of the placebo effect, as well as the possible therapeutic benefit of irrigating the joint. Similar saline results were seen in the study that led to the drug's approval for knee pain.
No safety concerns arose during the study, which is particularly notable given that the patients were older and more likely to be on other medications and have additional diseases. Sixty percent of the patients were taking cardiac medications, approximately 55 percent took Cox-2 inhibitors prior to joining the study, and up to 14 percent were taking medication for diabetes.
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