The Hip Operation - Total Hip Replacement

Total Hip Replacement

There are two types of total hip replacement surgery: cemented and cementless.

Cemented:

The surgeon will start by making an incision through the skin and then through the muscle layers. There are many different types of approach to this and is down to surgeon preference. The surgeon will prepare the soft tissues before operating on the bony areas. Your hip will then be dislocated in order to gain access to the bony parts that need to be replaced.

Then, the acetabular (socket) will be reamed using a sharp hemispherical cheese grater like instrument, here all of the hard bone is removed until there is a good bed of spongy bone (cancellous bone). The surgeon will then measure what size of cup is most appropriate and using bone cement will fix a polyethylene cup in place. Cemented acetabular cups are only made from polyethylene and can be either standard of crosslinked that can affect the rate in which they will wear out.

Then the femur (thigh bone) is prepared and shaped to fit the hip stem prosthesis. This is also fixed in place using bone cement. Your surgeon will then choose a head to fix onto the hip stem, which will articulate (move within) the cup. This head comes in a variety of sizes and will be made of either metal or ceramic.

Your hip is then reduced (put back together) and your surgeon will check your leg length to ensure that both sides are similar, they may not always be exactly the same length as naturally we can have around 1cm leg length discrepancy.

Cementless:

The surgeon will start by making an incision through the skin and then through the muscle layers. There are many different types of approach to this and is down to surgeon preference. The surgeon will prepare the soft tissues before operating on the bony areas. Your hip will then be dislocated in order to gain access to the bony parts that need to be replaced.

Then, the acetabulm (hip socket) will be shaved using a sharp hemispherical cheese grater like instrument, here all of the hard bone is removed until there is a good bed of spongy bone (cancellous bone).

The surgeon will then measure what size of cup is most appropriate and implant an uncemented cup. This is secured in place by a press fit, which basically means making a hemispherical shape within your pelvis into which a similar sized hemispherical piece of metal will be placed. Additional fixation is ensured by the coating on the metal, this is usually rough metal beads, which dig into the bone or hydroxyappetite (HA) which is a synthetic bone substitute.

Your surgeon will then choose an appropriate lining to the metal shell he has implanted. The liner options are varied in size and material. The material options are polyethylene, metal and ceramic and can affect the rate in which they will wear out.

Then the femur (thigh bone) is prepared and shaped to fit the hip stem prosthesis. This is also fixed in place without using bone cement.

Your surgeon will then choose a head to fix onto the hip stem, which will articulate (move within) the cup. This head comes in a variety of sizes and will be made of either metal or ceramic.

Your hip is then reduced (put back together) and your surgeon will check your leg length to ensure that both sides are similar, they may not always be exactly the same length as naturally we can have around 1cm leg length discrepancy.