How long does it take the bone to grow into my hip implant?

Most modern hip replacements are put in a "press-fit" fashion with a special roughened coating that is designed for you bone to grow into and essentially become part of your body.  However it takes about 6-8 weeks for this to happen.  The early hip replacements used bone cement to hold the implant into the bone.  Today, we use cement in cases where the bone quality is not sufficient enough to hold a press-fit implant, such as older patients who suffer a hip fracture and need a partial hip replacement.  Knee replacements also use cement to hold the implant in the bone.