Gender-Neutral Implants Should Suffice for Total Knee Replacement: Presented at AAOS

By Roberta Friedman, PhD

SAN FRANCISCO -- March 7, 2008 -- Joint registry data presented here at the American Academy of Orthopaedic Surgeons (AAOS) 75th Annual Meeting do not support the use of gender-specific joint implants.

The marketing of such sex-specific hip and knee devices is based on the assumption that surgical outcomes differ by gender, yet the large data set does not bear out this assumption for knee replacement, researchers said in a poster presentation.

Investigator William Timothy Brox, MD, Staff Orthopaedic Surgeon, Kaiser Permanente, Fresno, California, presented data from 20,718 primary total knee arthroplasty procedures showing that implant survival did not differ between the sexes at 2 years of follow-up.

Dr. Brox said on March 6 that he "cannot justify the increased cost of a thousand dollars" per joint for patients who might request a gender-specific device.

In the community-based registry funded by Kaiser, data were available on 7,468 men and 13,250 women. Mean age at implant did not differ between the 2 groups. After at least 9 months of follow-up, pain scores on a visual analog scale improved by 5.41 points for women and 5.05 points for men (P

Need for revision surgery did not differ significantly, nor did the range of motion between men and women.

"Outcome data should justify the need for new, gender-specific implants," Dr. Brox said, but this study does not lend support to this approach, at least with "this relatively short follow-up study," he said.

[Presentation title: Are Gender-Specific Implants Necessary for Total Knee Replacement? Abstract P172]

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