The Operation

Anaesthesia: A hip replacement operation is performed in a special orthopaedic operating room, where extra precautions are taken to minimise the risk of infection. While the type of anaesthetic must be selected by the specialist anaesthetist, according to individual patient requirements, a spinal anaesthetic is the most commonly preferred. This is supplemented by sedation or a light general anaesthetic, so the patient is comfortable and not awake or partly aware, during the operation.

Accessing the Joint: The steps involved in replacing the hip begin with making an incision on the side of the thigh and then carefully dissecting through the soft tissues; muscles,  ligaments and the joint capsule, to allow access to the hip joint. There are several different approaches used to make the incision, usually based on the surgeon's training and preferences.

Removing the Femoral Head: Once the hip joint is exposed, the femoral head is actually dislocated from the acetabulum (socket) and the femoral head is removed by cutting through the femoral neck.

Click here to view an animation - Removing the Femoral Head.
 

Reaming the Acetabulum: Attention is then turned toward the socket where, using a power drill and a special reamer, the worn cartilage is removed completely from the acetabulum and the bone is formed in a hemispherical shape to exactly fit the metal shell of the acetabular component.

Click here to view an animation - Reaming the Acetabulum.
 

Inserting the Acetabular Component: Once the right size and shape is determined for the acetabulum, the acetabular component is inserted into place. In the uncemented variety of artificial hip replacement, the metal shell is simply held in place by the tightness of the fit or by using screws to hold the metal shell in place. Over the next few weeks, tissue grows into the fine mesh of holes in the metal to attach the implant to the bone. With a cemented prosthesis, a special bone cement is used to anchor the acetabular component to the bone.

Click here to view an animation - Inserting the Acetabular Component.
 

Preparing the Femoral Canal: To begin replacing the femur, special rasps are used to shape the hollow femur to the exact shape of the metal stem of the femoral component.

Click here to view an animation - Preparing the Femoral Canal.
 

Inserting the Femoral Stem: Once the size and shape are satisfactory, the stem is inserted into the femoral canal. If the femoral component is uncemented, 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 drilled into wooden board, with a slightly smaller diameter than the nail). With a cemented component, the femoral canal is rasped to a size slightly larger than the femoral stem, and methacrylate cement is used to bond the metal stem to the bone.

Click here to view an animation - Inserting the Femoral Stem.
 

Attaching the Femoral Head: The last step in the procedure before closing the incision is attaching the metal ball that replaces the femoral head.

Click here to view an animation - Attaching the Femoral Head.
 

Closing the Incision: The deep tissues, hip joint ligaments and capsule are repaired first, to stabilize the joint. Then the muscle layers and sub-cutaneous tissues are sutured back in place.There are several ways that orthopaedic surgeons close the skin incision after performing an artificial joint replacement. Staples, nylon sutures, or sub-cutaneous self absorbing sutures can all be used, and depend on the surgeon's preference. 

Click here to view an animation - Implant Completed.