New York—March 11, 2014
Their study found that middle-aged women with rheumatoid arthritis or arthritis resulting from an injury tend to experience more pain after the surgery, underscoring the importance of a good pain management program in hospitals where knee replacement is performed.
“There is no question that pain after total knee replacement is greater than that after total hip replacement,” says 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.”
In two companion studies presented at the annual meeting of the American Academy of Orthopaedic Surgeons in New Orleans on March 11, Dr. Sculco and colleagues also found that surgical factors like having general anesthesia as opposed to epidural anesthesia also can play a role in pain following surgery.
For the studies, the researchers reviewed hospital records for 273 patients who underwent total knee replacement from October 2007 to March 2010. For the first study, 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.
“Before patients come in to the hospital, surgeons should have a thorough discussion with them regarding postoperative pain, particularly in the groups that we found tended to have more pain,” Dr. Sculco says. “More aggressive pain management techniques may be necessary for these patients.”
For the second study, the researchers used the same medical records to gather information about surgical variables including the length of the incision, how long the procedure took, and radiographic assessment including the amount of knee deformity and implant positioning and alignment.
Risk factors for increased postoperative pain included having general anesthesia as opposed to an epidural and having a large kneecap. Surgical technique can play a role in reducing pain, Dr. Sculco says.
“The surgeon must be aware not to use an implant that is too large for the knee, or a kneecap component that is excessive in size. In addition, the location of the joint line must be accurately positioned after the knee replacement, for if it is too high it may lead to increased pain.” Patients with epidural anesthesia also tended to have less pain than those who had general anesthesia, he says.
“Technical accuracy is important, particularly the alignment, patella sizing and joint line level,” Dr. Sculco says. “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.”
About HSS | Hospital for Special Surgery
HSS is the world’s leading academic medical center focused on musculoskeletal health. At its core is Hospital for Special Surgery, nationally ranked No. 1 in orthopedics (for the ninth consecutive year) and No. 3 in rheumatology by U.S.News & World Report (2018-2019). Founded in 1863, the Hospital has one of the lowest infection rates in the country and was the first in New York State to receive Magnet Recognition for Excellence in Nursing Service from the American Nurses Credentialing Center four consecutive times. The global standard total knee replacement was developed at HSS in 1969. An affiliate of Weill Cornell Medical College, HSS has a main campus in New York City and facilities in New Jersey, Connecticut and in the Long Island and Westchester County regions of New York State. In 2017 HSS provided care to 135,000 patients and performed more than 32,000 surgical procedures. People from all 50 U.S. states and 80 countries travelled to receive care at HSS. In addition to patient care, HSS leads the field in research, innovation and education. The HSS Research Institute comprises 20 laboratories and 300 staff members focused on leading the advancement of musculoskeletal health through prevention of degeneration, tissue repair and tissue regeneration. The HSS Global Innovation Institute was formed in 2016 to realize the potential of new drugs, therapeutics and devices. The culture of innovation is accelerating at HSS as 130 new idea submissions were made to the Global Innovation Institute in 2017 (almost 3x the submissions in 2015). The HSS Education Institute is the world’s leading provider of education on the topic on musculoskeletal health, with its online learning platform offering more than 600 courses to more than 21,000 medical professional members worldwide. Through HSS Global Ventures, the institution is collaborating with medical centers and other organizations to advance the quality and value of musculoskeletal care and to make world-class HSS care more widely accessible nationally and internationally.