Embargoed: 12:01 a.m. PT
March 24, 2015

Men have a higher level of function before and after total knee replacement surgery

Men, women have comparable implant survival rates, range of motion and level of improvement

—While men and women have similar levels of improvement following total knee replacement (TKR) surgery, men have higher levels of function before and after TKR, according to new research presented today at the 2015 Annual Meeting of the American Academy of Orthopaedic Surgeons (AAOS).


According to the Agency for Healthcare Research and Quality, more than 600,000 knee replacements are performed in the U.S. each year. In 2012, 393,345 women and 237,896 men underwent TKR, most often to alleviate the pain and immobility associated with late-stage arthritis. While research has looked at the anatomic differences between the knees of men and women, the higher levels of arthritis in women versus men, and the utilization of TKR among men and women, there has been little study on how gender influences the level of function before and after surgery.
In this study, researchers identified and studied 287 TKR patients at seven different institutions between 2005 and 2007. All of the patients were between the ages of 21 and 80 at the time of surgery and a body mass index <40 g/m². All of the patients except two had a diagnosis of end-stage arthritis. The patient group included 108 men (112 knees) with a mean age of 67, and 170 women with a mean age of 66.  All of the patients were evaluated preoperatively and at the following six points following surgery: six weeks, three months, one year, two years, five years and seven years. A Kaplan-Meier assessment gauged implant survival, and quality of life measurements were taken at three and four years post-surgery. During each evaluation, researchers measured knee function, range of motion, extremity activity and overall health.


At five years post-surgery, implant survival was 100 percent for men and 99.1 percent for women. Range of motion also was nearly identical between genders. Functional scores were consistently higher for the men versus women: preoperatively, 57.1 versus 51; postoperatively at six weeks, 63.7 versus 51.5; at three months, 83.1 versus 74.3; at two years, 90 vs. 81.6; at five years, 90.1 vs. 82.9; and at seven years, 96 vs. 79.5. Men also recovered faster within the six week recovery time after surgery; however, both genders had almost identical improvement in mean knee score function (improvement from presurgical levels) at five years. 


“Our data supports that while both genders benefit from TKR, men have higher levels of function and activity both prior to and after TKR compared to women,” said lead study authors Jeffrey J. Cherian, DO and  Michael A. Mont, MD. “These functional outcome differences are most likely due to many factors (including biologic/genetic) and highlight the need for further research related to the role of gender of both the patient and the surgeon in the decision making process of TKR, sex-based biological differences in functional recovery capacity, and whether sex/gender based pre- and postoperative rehabilitation protocols are warranted.”


# # #


Study abstract


View 2015 AAOS Annual Meeting disclosure statements


About AAOS


Follow us on Facebook.com/AAOS1 and Twitter.com/AAOS1


Orthopaedic surgeons restore mobility, reduce pain and provide value; they help people get back to work and to independent, productive lives. Visit ANationInMotion.org to read successful orthopaedic stories.

For more information on bone and joint health, visit Orthoinfo.org.



Print   Download Print-friendly PDF

Multimedia Gallery

Click here to view and download images and videos
from our multimedia gallery.
  Ortho Stats

Ortho Stats & Facts

Click here to find data
to supplement your news.

Join Us
Facebook Twitter YouTube Google+


Facebook Twitter Share Email

For inquiries on this release, contact :

Kristina Goel
P: 847-384-4034 • M: 312-388-5241 • goel@aaos.org

Lauren Pearson Riley
P: 847-384-4031 • M: 708-227-1773 • pearson@aaos.org

Click here to view Award Winner releases.

Click here to view Announcements.


Child pedestrians more likely to be struck by motor vehicles in the spring months, while unsupervised, near schools and bus stops

Spinal surgery diminishes low back pain, improves sexual function

Hip replacement patients may be able to safely drive as early as two weeks following surgery

Running barefoot may increase injury risk in older, more experienced athletes

The price of delirium: New study finds nearly half of patients have delirium before and after hip fracture surgery, diminishing outcomes and increasing care costs

Routine bisphosphonate treatment for women over age 65 who sustain a wrist fracture could prevent nearly 95,000 hip fractures, but at a significant cost

Men have a higher level of function before and after total knee replacement surgery

Diabetes, previous joint pain and overall physical health predicts arthritis pain


Majority of parents, caregivers of youth baseball pitchers unaware of safe pitching practices designed to prevent overuse injuries

Study identifies smoking, obesity, alcohol abuse and depressive disorders as low back pain risk factors


Middle-age hip replacements nearly double from 2002-2011, outpacing growth in elderly population

Stem cells may significantly improve tendon healing, reduce retear risk in rotator cuff surgery

Black, Hispanic patients more likely to be readmitted to the hospital for a complication within 30 days following hip or knee replacement surgery

Women fare better than men following total knee, hip replacement


More than one-third of Division I college athletes may have low vitamin D levels