Research Suggests Women Overly Delay Knee Replacement

Study by University of Delaware Professor of Physical Therapy Proves Putting Surgery on Hold Affects Quality of Life

ALEXANDRIA, VA, February 4, 2008 — A new study out of the University of Delaware (UD) indicates that women may wait too long to pursue knee-replacement surgery. "By postponing surgery until they can no longer stand the pain, these women also may risk putting their mobility-and their quality of life-on hold indefinitely," says Lynn Snyder-Mackler, PT, ScD, SCS, ATC, FAPTA, distinguished alumni professor in UD's Department of Physical Therapy and a certified sports physical therapist and athletic trainer.

"Physicians typically tell patients to wait to have knee replacements until they just can't stand the pain any longer," Snyder-Mackler said. "Our research shows that may be bad advice-and worse for women than it is for men-because your level of function going into surgery generally dictates your level of function after surgery," she noted.

Snyder-Mackler led the research team for the study, which was funded by a $1,125,000 million grant from the National Institutes of Health (NIH). At the University's Physical Therapy Clinic, 229 candidates for total knee replacements, including 95 men and 126 women with osteoarthritis, were evaluated and compared with 44 healthy men and women who matched them in gender, age, and body-mass index. Each subject took part in a series of standard physical tests such as stair climbing and the distance covered in a 6-minute walk.

The strength of the participants' quadriceps-the major thigh muscle that extends and straightens the knee-and range of motion of the knee also were assessed at the clinic. While the men generally were stronger and had more knee function than the women, the test results showed a much greater degree of physical disability in the female knee-replacement candidates compared with the male knee replacement candidates.

"Both the men and women had osteoarthritis, but the women were at much more advanced stage than the men with the disease," Snyder-Mackler said. "Despite both groups having painful, end-stage osteoarthritis, where the cushion of cartilage padding the knee bones has completely deteriorated and you basically have bone hitting against bone, the women demonstrated a marked decrease in function compared with the men."

Snyder-Mackler observes that there may be a number of reasons why women may wait so long before pursuing surgery. She suggests that perhaps women can bear pain better than men, or a woman's world increasingly revolves around the home as she ages, or it could be that women are just trying to follow doctor's orders. "Osteoarthritis of the knee is the most common cause of disability among Americans. It's a disease of age that affects more women than men on a 60-40 basis," Snyder-Mackler said. "Physicians generally have advised patients to wait as long as they can before pursuing knee replacements, with the thinking that it is a once-in-a-lifetime surgery that should last an average of 20 years."

Snyder-Mackler concludes that women need to become more educated about the risks and benefits of knee-replacement surgery, and heed the warning signs of serious problems. "When you feel profound buckling and weakness in your knee when climbing stairs, that is a tell-tale sign of a major problem," she notes. "You end up compensating, say, by avoiding the stairs. As a result, you become sedentary, and that's not good for your health. Earlier intervention can help preserve your mobility and quality of life."

Snyder-Mackler notes that, if possible, once patients have been diagnosed with osteoarthritis, they should try to remain fit and keep muscles strong through exercise, which will help post-surgery. "The candidates for knee-replacement surgery are not going to get their new knees and start running marathons," she notes. "Their goal-as well as the goal of their physical therapist-is simply to resume normal, daily functions without any pain or discomfort."

Physical therapists are health care professionals who diagnose and manage individuals of all ages who have medical problems or other health-related conditions that limit their abilities to move and perform functional activities in their daily lives. Physical therapists examine each individual and develop a plan of care using treatment techniques to promote the ability to move, reduce pain, restore function, and prevent disability. Physical therapists also work with individuals to prevent the loss of mobility by developing fitness- and wellness-oriented programs for healthier and more active lifestyles.

The American Physical Therapy Association ( is a national organization representing physical therapists, physical therapist assistants, and students nationwide. Its goal is to foster advancements in physical therapist education, practice, and research. Consumers can access "Find a PT" to find a physical therapist in their area, as well as physical therapy news and information at