A new design of knee replacement implant could bring about better results for women requiring the procedure.
The Zimmer knee implant is designed to fit women knees more effectively, taking account of the fact that they tend to be deeper and narrower than men's knees.
Nick London, a knee surgeon, told the BBC: "Knee replacements have become a phenomenal success, but surgeons have noticed in the last few years that men and women are behaving differently after operations.
"For a lot of women, the replacement doesn't quite match the end of the femur and in the last few years that has made a difference to their pain."
The new design aims to deal with this problem by fitting more effectively around the femurs of women.
The design has been used on more than 32,000 patients in the US. The first British patient was 76-year old Eileen Taylor.
She told the Argus: "The improvement since my operation has been excellent. I am getting better daily and can bend my knee much better.
"It is still early days but I'm walking so much better than I did before my operation and the pain has reduced significantly."