The surgeon begins by making an incision to allow access to the hip joint. Several different approaches, known as anterior, lateral or postero-lateral approachs are used to make the incision based on the surgeon’s training and preferences. Once the hip joint is entered, the surgeon dislocates the femoral head from the acetabulum. The femoral head is then removed by cutting through the femoral neck with a power saw. The surgeon then uses a power drill and a special reamer, a cutting tool used to enlarge or shape a hole, to remove the remaining of cartilage from inside the acetabulum. The surgeon shapes the socket into the form of a half-sphere to allow the metal cup of the acetabular component to fit perfectly inside. After shaping the acetabulum, the surgeon tests the new component to make sure it fits just right.
In the uncemented variety of artificial hip replacement, the metal cup is held in place by the tightness of the fit and in-growth of tissue; screws may be used for additional fixation if necessary. In the cemented variet, a special epoxy-type cement, known as bone cement, is used to anchor the acetabular component to the bone.
To begin replacing the femur, special rasps (filing tools) are used to shape and hollow out the inside of the femur to the exact shape of the metal stem of the femoral component that will be used.
Once the size and shape are satisfactory, the stem is inserted into the femoral canal. Again, in the uncemented variety of femoral component, the stem is held in place by the tightness of the fit into the bone (similar to the friction that holds a nail driven into a hole that is slightly smaller than the diameter of the nail) and if the component has a porous structure by in-growth of tissue. In the cemented variety, the femoral canal is enlarged to a size slightly larger than the femoral stem and the epoxy-type cement is used to bond the metal stem to the bone. The metal ball that makes up the femoral head is then attached to the stem. Once the surgeon is satisfied that everything fits properly, the incision is closed with stitches.
Several layers of stitches are used under the skin, and either stitches or metal staples are then used to close the skin. A bandage is applied to the incision, and you are returned to the recovery room.