Who experiences the most pain following a total knee replacement (TKR)? According to a study by researchers from Hospital for Special Surgery (HSS) in New York, it is middle-aged women with rheumatoid arthritis who experience the most pain. Almost all patients are concerned about the pain they may have following knee replacement surgery. While all patients experience some pain, for some patients persistent postoperative pain can present a major problem.
“There is no question that pain after total knee replacement is greater than that after total hip replacement, ” said senior study author Thomas P. Sculco, M.D., the hospital’s surgeon-in-chief. “Many factors play a role, and our studies found that younger female patients, particularly those with post-traumatic or rheumatoid arthritis, had the highest pain scores.”
Sculco and his colleagues also found that surgical factors like having general anesthesia or a longer tourniquet time during knee replacement also can contribute to pain following surgery.
For their studies, the researchers reviewed hospital records for 273 patients who underwent total knee replacement from October 2007 to March 2010. The investigators looked at demographic data such as gender, ethnicity, age, height, weight, type of knee arthritis and co-existing medical conditions. They also looked at the knee’s preoperative range of motion, how well the patients could walk and the amount of pain they had before surgery.
The strongest predictors for severe postoperative pain during rest included being female; being between the ages of 45 and 65; having post-traumatic arthritis spurred by an injury, rheumatoid arthritis, or osteoarthritis; being obese; and having a higher level of pain at the time of hospital admission.
During periods of activity, obesity, a higher pain level during hospital admission and being between the ages of 45 and 65 were the strongest predictors of postoperative pain. Patients who were Asian or Caucasian, and those with either underlying osteoarthritis or avascular necrosis, or both, had lower postoperative pain during periods of activity
Risk factors for severe postoperative pain at rest included having general anesthesia as opposed to an epidural or spinal block, longer tourniquet time, more blood loss, and having a large kneecap.
“Technical accuracy is important, particularly the alignment, patella sizing and joint line level, ” Sculco said. “Patients with more complex preoperative deformities often required increased operating time and surgical dissection, which in turn led to increased pain, especially in the younger female patients.”
