Two methods ease pain equally after knee surgery

NEW YORK (Reuters Health) - For controlling pain after a certain type of knee surgery, continuous nerve blocks offer no advantage over conventional painkilling injections, a new study has found.

Evidence for the benefits of nerve block for pain control after surgery to reconstruct the anterior cruciate ligament (ACL) has been mixed, Dr. G. William Woods of the University of Texas Medical School at Houston and colleagues note in the American Journal of Sports Medicine.

The researchers set out to compare two protocols for post-ACL reconstruction pain control that were currently in use at their hospital. One involved deadening the femoral nerve in the leg with an anesthetic delivered continuously via a catheter, and giving patients oral pain medication, with morphine injections prescribed for breakthrough pain.

In the other protocol, used at the hospital for more than 10 years, patients received an injection of pain-killing medication into the knee, oral pain medication and morphine injections as needed.

Woods and his team thought that patients given the nerve block would require less pain medication and experience less pain. To investigate, they randomly assigned 90 patients undergoing ACL reconstruction to one of the two protocols.

Pain scores between the two groups were not significantly different. Patients given the nerve block used significantly more oral pain medication, but those who received injections into the knee were more likely to require injections for breakthrough pain.

The researchers also found no difference between the two groups in their ability to move around after surgery and to perform rehabilitation exercises, and both groups were equally satisfied with their pain control.

"Both methods are effective for pain control after anterior cruciate ligament reconstruction," the researchers conclude.

SOURCE: The American Journal of Sports Medicine, August 2006.