MEDICA.de: Dr. Heisel, are male and female joints different?
Dr. Christian Heisel: There are of course some certain differences in the anatomy that can be measured such as gender-specific angles and dimensions in the knee, also female pelvises are broader and therefore the biomechanics of the hip joint differs between the sexes.
MEDICA.de: Which sex has rather been used as the standard for developing, for example, knee prostheses - men or women?
Heisel: The first knee prostheses have been developed more than 20 years ago and I think that mixed examinations have been the basis. The situation today is as follows: companies develop a certain design for a knee prosthesis and produce them in different sizes.
MEDICA.de: Certain differnces exist between male and female joints. Are these differences truly larger than the differences between individuals such as a small and a large woman, a woman with a small and a broad pelvis?
Heisel: In my opinion: No. The transitions are seamless between individuals. For example: it is not possible to take a look at an X-ray of a knee and then decide whether it belongs to a man or a woman.
MEDICA.de: How is it possible then that some companies develop knee prostheses that are developed specifically for female needs?
Heisel: I think that this is just a big marketing strategy. If you consider the results of knee replacements, it would basically mean that women should have worse outcomes. This is not the case.
MEDICA.de: Do we need artificial hip joints adjusted to female needs?
Heisel: No. Artificial hip joints already exist in many different types - there is absolutely no need for it.
MEDICA.de: Thinking about the issue theoretically, are there any other joints that would justify gender-specific prostheses?
Heisel: No, nobody is seriously thinking about such a development. Main targets in medicine conderned with endoprostheses should be to better anchor them in the bone, to reduce wearout, avoid breakage and to improve their lifespan.
MEDICA.de: Is it possible to comment on a trend where the development of endoprostheses goes to? Something such as the individual prsothesis for everybody regardless of age or gender?
Heisel: Such a scenario would be imaginable but I am not sure if it was necessary. The spendings would be too high and the benefits too low. Prostheses anyhow become more and more modular and are therefore prone to be put together in many different ways.