Women wait longer than men to undergo TKA for knee OA, study suggests

Women showed lower SF-36 physical component scores and lower Knee Outcome Survey scores, indicating greater disability.

Women may delay undergoing total knee arthroplasty to treat knee osteoarthritis longer than men, electing to receive surgery at a more advanced disease state, according to a study by researchers at the University of Delaware.

"Doctors typically tell patients to wait to have knee replacements until they just can't stand the pain any longer," Lynn Snyder-Mackler, PT, ScD, senior author of the study, said in a press release from the university.

"Our research shows that's 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 said.

Snyder-Mackler and colleagues at the university's Physical Therapy Clinic in McKinly Laboratory, Newark, Del., evaluated 229 patients with knee osteoarthritis (OA) who were candidates for total knee arthroplasty (TKA), including 95 men and 126 women. These patients were compared to a control group of 44 healthy men and women who were matched for gender, age and body mass index (BMI).

Each participant completed a series of standard physical tests such as stair climbing and the 6-minute walk.

Investigators found that men were generally stronger and had greater knee function compared to women. However, women in the study group showed a much higher level of physical disability compared to men.

"Women in the arthroplasty group had lower SF-36 (Short Form-36) physical component scores, SF-36 mental component scores and Knee Outcome Survey scores in comparison with men (P < .05), indicating greater reported disability," the study authors reported.

In addition, women in the study group had longer up-and-go test times, longer stair-climb test times and shorter 6-minute walk distances (P < .001). However, men and women arthroplasty candidates showed similar results for knee flexion and knee extension.

"[The] gender-by-limb interaction term ... for range of motion were not significant, with the numbers available," the authors wrote.

Also, "The women afflicted with osteoarthritis were at a much more advanced stage than the men with the disease," Snyder-Mackler said in the release.

"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. However, delaying surgery can limit the quality of life of patients, because how they function before surgery indicates their performance afterward," Snyder-Mackler said in the release.

For more information:
Petterson SC, Raisis L, Bodenstab A, Snyder-Mackler L. Disease-specific gender differences among total knee arthroplasty candidates. J Bone Joint Surg Am. 2007;89-A:2327-2333.