Yes, psoas tendinitis is an important reason for groin pain in resurfacing surgery .
This is peculiar to resurfacing as the cup for resurfacing is a very large profile ie half a sphere. Nearly all THR cups are only portions ( arc) of a hemisphere.
Hence if the antero-posterior orientation i.e., version of the cup is marginally off the ideal, it would not be a problem with THR. However in resurfacing, due to the very large profile, if the version is less than ideal the ant edge of the cup will protrude out of the bony front wall of the acetabulum. The psoas tendon will rub on this and patients will typically complain of pain when attempting to lift their leg in a standing position.
For this reason we now take extra care to get the version right and most resurfacing surgeons leave a 3mm rim of osteophytes over the ant edge as a safety precaution to avoid this problem.
with best regards, vijay bose, chennai