FRIDAY, June 25 (HealthDayNews) -- Widely used pain-relief drugs may actually interfere with healing in a common shoulder-repair surgery, researchers report.
Nonsteroidal anti-inflammatory drugs (NSAIDs) -- which include aspirin, ibuprofen, and arthritis drugs such as Celebrex and Vioxx -- are often the medication of choice to relieve post-operative pain following rotator-cuff surgery.
But according to a new study, these drugs may also have adverse effects on bone healing, which is a necessary part of rotator-cuff recovery.
The findings, which are being presented Friday at the meeting of the American Orthopaedic Society for Sports Medicine in Quebec City, Canada, have been verified only in rats, and are therefore extremely preliminary.
Almost 2 million people in the U.S. seek care for rotator cuff problems each year. The rotator cuff consists of muscles and tendons surrounding the top of the upper arm bone that work together to hold it within the shoulder joint. Rotator cuff injuries are especially common in people over the age of 40.
Most rotator cuff repair involves reattaching the tendon back to the bone and then letting the bone grow back into the tissue. However, "our failure rates are quite high, up to 50 percent," said Dr. Scott A. Rodeo, one of the authors of the study and an associate professor of orthopedic surgery at the Hospital for Special Surgery in New York City.
Although NSAIDs have not been studied yet in tendons-to-bone healing, they have been shown to negatively affect healing of fractures, spinal fusions, and ligament healing.
"The interaction between NSAIDs and the process of healing has been suspected for a long time and is the source of an ongoing argument," said Dr. Michel Dubois, director of the New York University Pain Management Center and professor of anesthesiology at New York University School of Medicine, both in New York City.
"NSAIDs may interfere with the process of healing by their very nature," he said. "They are supposed to fight inflammation, but inflammation is part of the healing process."
"Healing really invokes bone formation, so based on that and the fact that NSAIDs can impair bone healing, we thought these medications may impair healing," Rodeo said. "Are they having a detrimental effect on basic biology and basic healing?" Rodeo asked.
For this study, the researchers performed rotator-cuff surgery on 180 laboratory rats. One-third of the animals were treated with the NSAID Indocin. Another third were treated with Celebrex, one of a newer class of NSAIDs called cox-2 inhibitors, and the final third were given standard rat food with no medication.
The tendon-to-bone healing in the rats treated with either of the two medications was "distinctly less robust" than in the control group. Five tendons (four in the celecoxib group and one in the Indocin group) did not heal at all after eight weeks. All the tendons in the control group healed.
Although the rat model is standard for this type of study, "there are limits to how much we can extrapolate," Rodeo conceded. The results need to be validated in larger animal models, possibly sheep, he added.
If in fact it does turn out that NSAIDs were inhibiting healing in humans, there are several alternative medications for pain relief, including acetaminophen medications such as Tylenol, or various opiates.
But Dubois noted that the "the advantage of NSAIDs is the fact that they are supposed to have less side effects."
For more on rotator cuff problems, visit the American Academy of Orthopaedic Surgeons.