Hip replacement is commonly performed under a general anaesthetic combined with injecting local anaesthetic around the joint. A skin incision is made over the side of the hip. The upper part of the thigh bone (head of femur) is cut and the natural socket (acetabulum) is hollowed (reamed) out. A cup is fitted into the hollow in the acetabulum. A short, angled metal shaft (the stem) with a smooth ball on its upper end is placed into your femur. The cup and the stem may be pressed into place (un-cemented THR) or fixed with bone cement (cemented THR) .
Cemented Hip replacement
Cemented Total Hip: When the stem and cup are attached to the bone & socket with acrylic (a special form of plastic) cement. Cement functions as a grout, producing an interlocking fit between the bone and prosthesis.
Un-cemented Hip Replacement
Uncemented Total Hip: Rather than using cement, these are fixed into the bone using very accurate reaming of the bones, and a special coating on the prostheses into which the bone will grow. This is a material called hydroxyapatite which is a porous coating, sometimes made of very tiny beads formed in the manufacture of the implants. The intention is that new bone will grow into this coating thus making a strong bond between the implant and the bone. In order to facilitate this growth, it is necessary for the preparation of the bone be done with care and accuracy, ensuring a close, tight fit (press fit) .
Hybrid Hip Replacement
Hybrid Total Hip: When only one part of the new joint is fixed using cement. The femoral component is cemented into place while the cup is fixed without cement.
Resurfaced Hip Replacement
Resurfaced Hip: here instead of removing the top section of the thighbone surgeons fit a hollow metal cap over the head of the thighbone. They also resurface the socket part of the joint with metal. This type of implant is known as metal-on-metal (MoM).