The more weight on this part, the quicker the liner will wear thin and require replacing
. This is why they won't do knee
or hip replacements
on the obese - it'll wear out in a year and the patient will be back to square one. This is major, major surgery and you don't want to repeat it if you don't have to.
There is a new class of implants out though, for which I don't qualify because i've had too much bone removed. I don't know if this would be an option for him or not.