Gender Bender: Do Gender Knee Implants Provide Better Outcomes?

/PRNewswire/ -- A gender-specific total knee prosthesis was developed to more closely match the anatomy of the female knee, aiming to be a better fit resulting in better outcomes for women. However, a recent study in the Journal of Bone and Joint Surgery (JBJS) found that 85 women who received a gender-specific implant in one knee and a standard prosthesis in the other knee found no clinical benefits of the gender-specific knee.

"We conducted this study to investigate whether women derive less benefit, or perhaps less predictable benefit, from total knee replacement using a standard conventional total knee implant," said Young-Hoo Kim, M.D., orthopaedic surgeon and lead author of the study.

After receiving knee implants - one gender-specific and one standard prosthesis - the women were assessed for at least two years after surgery. The knees with the gender-specific implant and the knees with the standard implant had similar knee scores and similar range of motion while lying down (125 degrees for the knees with standard implants and 126 degrees for the knees with gender-specific implants). All patients except three were able to bend their knees at least 90 degrees.

Additionally, patient satisfaction with the implants was similar (8.3 points for the standard implants and 8.1 points for the gender-specific implants). A rating of 6 to 8 meant "satisfied," and a rating of 9 to 10 meant "fully satisfied."

Important findings included:
-- The majority of women in the study (71 females or 84 percent) had no
preference between the two implants,
-- eight women (9 percent) preferred the standard prosthesis, and
-- six (7 percent) preferred the gender-specific prosthesis.

Implantation prostheses of either design resulted in improved quality of life in terms of pain, walking distance, deformity, and function after surgery.

Although the gender-specific implants were specially designed to fit women, Dr. Kim's study showed that the standard prostheses fit women's knees better than the gender-specific implants. "Our data demonstrated that the standard prosthesis fit the distal part of the femur (where the thigh and knee connect) better than the gender-specific prosthesis did," said Dr. Kim, who is from The Joint Replacement Center of Korea, Ewha Women's University School of Medicine in South Korea. The gender-specific prosthesis was so small that it exposed more bone, which resulted in increased bleeding immediately after surgery.

Dr. Kim and his colleagues were surprised by the study results. "We indeed expected the gender-specific prostheses to outperform the standard prostheses," he said.

Because the women in the study did not have any clinical benefit from the gender-specific knee implants, Dr. Kim now recommends that women receive a properly sized standard total knee prosthesis. "We have learned that gender-specific total knee prostheses fail to show any clinical benefits. So, we feel that proper size standard total knee prostheses are needed for both men and women," he added.

Although patients were only followed for approximately two years, studies have shown that results after two years are similar to those seen five to ten years after total knee replacement. "Because the duration of follow-up was short, we can draw no conclusions about the advantage of the gender-specific prosthesis with regard to long-term function," Dr. Kim concluded.

Disclosure: The authors did not receive any outside funding or grants in support of their research for or preparation of this work. Neither they nor a member of their immediate families received payments or other benefits or a commitment or agreement to provide such benefits from a commercial entity.

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Custom-Fit OtisKnee™ May Impact Early Success of Total Knee Replacement Surgery, Study Finds

BUSINESS WIRE--A new study from the University of Alabama at Birmingham indicates that the OtisKnee Custom Fit Knee™ Replacement system may have a positive impact on length of hospital stay, range of motion, pain level and patient satisfaction immediately following total knee replacement surgery. The study abstract, titled “MRI-Guided Custom-Fit Total Knee Replacement: The First Six Weeks,” was presented at the joint Alabama Orthopedic Society and Mississippi Orthopedic Society annual meeting on May 3, 2008 in Sandestin, Fla. by Herrick Siegel, M.D., associate professor of surgery at the University of Alabama at Birmingham and lead investigator of the study.

Designed to evaluate the impact of OtisKnee on the early success of total knee replacement, the study involved 25 total knee replacements performed in 19 patients using the custom-fit OtisKnee technology. Each patient was followed for six weeks, a crucial period for predicting ultimate satisfaction with the procedure. Results showed that OtisKnee had a positive influence on length of hospital stay, range of motion, pain and patient satisfaction, as seen by the following data.

• Average length of hospital stay for single and bilateral (both knees) OtisKnee patients was 2.2 and 3.5 days, respectively.
• At two weeks, 17 of the 19 OtisKnee patients were walking with only a cane, and by 6 weeks all patients were walking without assistance.
• Sixteen of the 19 OtisKnee patients reported that they only needed prescription pain medication for 10 to 14 days post-op, and all patients were off prescription pain medication completely by four weeks post-op.

In addition, the study results indicated that OtisKnee is useful to the surgeon in pre-determining ideal implant size as well as defining proper rotation and positioning during the total knee replacement procedure.

“While total knee replacement has been a successful surgery historically, studies have shown that nearly 14 percent of patients have reported being dissatisfied or very dissatisfied with their surgery,” said Dr. Siegel. “Preliminary results with OtisKnee indicate that this unique, custom-fit approach may lead to a more predictable, reproducible and optimal result for patients.”

Since its limited U.S. launch in June of 2007, the OtisKnee technique has been performed by more than 400 surgeons on more than 7,000 patients. Initial clinical data demonstrating the value of OtisKnee in total knee replacement has been presented at the American Academy of Orthopaedic Surgeons annual meeting and has been accepted for publication in a peer-reviewed orthopedic trade journal.

Knee Specialist Dr. Patrick Barry Performing New Non-Surgical Procedure That Eliminates Knee Pain, Helps Patients Avoid Knee-Replacement Surgery

BUSINESS WIRE--Patrick Barry, MD, an orthopedic surgeon and knee specialist, today (May 7, 2008) announced he has developed an effective alternative to surgery that helps eliminate knee pain and helps patients avoid knee-replacement surgery, which is the traditional treatment for chronic knee pain. The new procedure helps patients enjoy increased mobility and return to normal activities.

The “manipulation-mobilization” procedure, which Dr. Barry pioneered and perfected during the past three years on hundreds of cases in the US and abroad, takes a few minutes to perform in the office. It enables many patients, some of whom entered the doctor’s office by limping or using crutches or walkers, to immediately stand, walk freely without assistance and climb stairs without pain. Some of these patients already had surgery at other facilities but still suffered from knee pain.

“This new procedure is an effective alternative for those who have been told surgery is their only option to relieve knee pain, and it also has value for those who have not had surgery and would like to avoid it, as well as those who have been undiagnosed and told there is nothing wrong,” says Dr. Barry, who has performed more than 10,000 knee surgeries during his extensive medical career. “Many patients find their knee pain persists even after surgery and they spend years on pain medications and in physical therapy, only to later be told by their doctors that they need additional surgeries. Since I began offering this treatment, I am performing far fewer surgeries. Patient satisfaction has risen dramatically, as this treatment helps restore patients’ quality of life and dignity.”

Dr. Barry says the procedure is beneficial for patients of all ages and body weights. Almost all patients show significant improvements and pain reduction within seconds after undergoing the procedure.