Male and Female Differences in Knee Injuries and Disease

Gender variances exist due to anatomic differences, hormones, and genetic factors.

ACL knee injuries occur at a higher frequency in female athletes – on the order of 3:1 vs age and sport matched males.

Osteoarthritis in the knee develops more frequently in women.  One explanation is that women lose healthy joint surface cells (articular cartilage) at 4 times the rate as men.  Obesity afflicts women more than men and this is one link to the greater incidence of knee OA.  Estrogen may play a role.

Replacing Knees Sooner in Women May Enhance Outcome

Conventional Orthopedic Surgical wisdom is to delay joint replacement until the patient is seriously impaired by their symptoms, even though on x-ray the patient’s knee joint is destroyed by arthritis. This means delaying surgery for serious knee arthritis until patients can not walk more than a block or two, can only ascend and descend stairs one at a time, patients are limping and patients have sleep disturbance from arthritis pain. Additionally, conventional wisdom recommends trials of NSAIDS (ibuprofen like meds), physical therapy, bracing, steroid injections or Hyaluronic Acid injections (synvisc and the like).

The lead article in the November, 2007 Journal of Bone and Joint surgery challenges this precept and presents strong scientific evidence to support the conclusion to operate sooner on women with serious knee arthritis that have measured functional deficits. The article is entitled Disease-Specific Gender Differences Among Total Knee Arthroplasty Candidates and was done at the University of Delaware.

Arthritis of the knee has a greater effect on knee function and strength in women, reflecting a gender difference in the disease impact. This larger impact on knee function in women is manifest by lower quadriceps muscle strength ( large muscle group in the front of the thigh), longer timed up and go standing test, longer timed stair climb, and shorter 6 minute walk distance compared to men with knee arthritis.

The logical and yet revolutionary conclusion is that strength and functional decline should be closely monitored (this functional testing could be documented by a Physical Therapist) in women with knee arthritis and when worsening is observed, joint replacement should be carried out. In some cases this may mean joint replacement is done sooner (compared to using traditional standards for deciding on the timing of surgery).

Closing the Gender Gap in Joint Replacement

It has been observed that there is an under use of Total Joint Replacement among willing and appropriate women who suffer from severe hip or knee arthritis. Even though women are as likely as men to seek treatment physicians are less likely to refer and recommend joint replacement surgery for women. Now that recognition of gender and cultural differences have been made, the focus is on more training for physicians in culturally competent patient care and shared decision making so that there will be a reduction in this disparity. Changes need to occur at the primary care level for referral to an orthopedic surgeon, better communication by all care providers so as to fully understand the severity of symptoms, the patient perceiving how severely debilitating their symptoms actually are, and dealing with issues related to surgery ( risks, interference with caregiver role, perceived burden on others during recovery process).