"While TKR is an effective surgical treatment one of the complications is chronic pain, a debilitating condition that can lead to a substantial reduction in quality of life with few effective treatment options," said Dr. Asokumar Buvanendran, associate professor of anesthesiology and director of orthopedic anesthesia at Rush Medical College, Chicago, Illinois.
"Searching for ways to improve the patient surgical experience, we evaluated pregabalin for effectiveness not as a treatment for chronic pain, but as a preventative of chronic neuropathic pain after surgery," the researcher added.
For the trial, 240 patients having knee replacement were divided into two groups. Half of the patients received 300 milligrams of pregabalin two hours before surgery, and repeated doses of 150 milligrams twice a day for 14 days following surgery.
The remaining patients received a matching placebo at the same time intervals.
All the patients received pain medication through a catheter following surgery, using a patient controlled epidural device (PCEA).
The researchers observed a dramatic decrease in the incidence of chronic neuropathic pain in patients who received pregabalin.
Six months following surgery, none of the patients in the pregabalin group reported the incidence of chronic pain, compared to 5.3 percent of patients in the placebo group.
Patients who received pregabalin experienced a greater knee range of motion (ROM) following surgery with the ability to perform simple tasks when returning home, such as climbing stairs with a ROM of 85 degrees compared to a ROM of 79 degrees for the placebo group.
The researchers said that such patients could climb stairs at 83 degrees of knee flexion, descend stairs at 90 degrees, and rise from a chair at 90 degrees.
"This is the first large prospective clinical trial examining the incidence of chronic pain after TKR and defining strategy to prevent the development of this debilitating chronic pain syndrome. With the promising treatment of pregabalin, patients may no longer delay needed orthopedic surgery for fear of pain after surgery and delayed rehabilitation," said Buvanendran.
The findings of the trial were presented at the 2008 Annual Meeting of the American Society of Anesthesiologists.