The Mayo Clinic did a study recently that confirms what you've found out. They reviewed over 27,000 cases of total hip replacement (THR). >From that study it looks like the number of nerve palsies after THR has gone up since 1989.

The increase is enough to notice but it's not dramatic. The overall incidence is still very low making this a rare complication.

Surgeons think the reason for the increase in number may be related to two things. First more patients are having hip replacement who wouldn't have qualified years ago. Today's newer methods make it possible to do a THR on someone with hip dysplasia or arthritis after a hip injury.

Second the newer cementless implants often require more pounding and hammering to get them in place. This may be too much stress and strain for the nearby nerves.

Complications are always likely when more complex patients with more challenging surgeries are being done. As surgeons become aware of the risk factors, efforts will be made to reduce problems even when they occur only rarely.