You are probably referring to the minimally invasive method of hip joint replacement. The doctor uses special tools and updated X-ray technology to guide the operation with just a small opening.
Surgery of any kind always runs a broad range of risks from minor infection to death. Infection can be a minor skin problem or a deep infection of the joint. This could lead to a failed operation or a second operation. With a joint replacement, fracture,
dislocation, and nerve injury are also possible.
Don't be afraid to ask your doctor to go over the list of possible problems. Find out if you have any risk factors to be concerned about.