Cemented or uncemented: Total hip replacement prostheses

A total hip replacement is a surgical procedure that uses an artificial implant, including cemented and uncemented prostheses, to replace a damaged hip joint in order to relieve pain and improve movement.

Here to provide an expert insight into a total hip replacement, the differences between cemented and uncemented prostheses and the duration of a hip implant, is Mr Ashraf Awad, revered orthopaedic hip and knee surgeon.

What is total hip replacement?

Total hip replacement is the operation that we do to replace the native hip joint, with an artificial hip.

This procedure is mainly done on the elderly population. However very recently, we've started to do this operation in the younger population, for one reason or another. Sometimes they have a very shallow hip joint that gives a lot of pain during regular activities. Sometimes it's because of cessation of blood supply; a condition that we call avascular necrosis, that can happen to the head of the femur in the hip joint, and it will lead to severe arthritic changes and severe pain that happens, leading to limitation of activities. 

The operation itself involves a replacement of the head of the femur with an artificial one; most likely a ceramic head. Also, in the pelvic bone will have to be prepared in a way so that we can put a shell inside, and a liner which, in the younger age population, will most likely be a ceramic one. However, in the older population it will most likely be polyethylene.

What is the difference between cemented and uncemented?

There are two types of hip replacement prosthesis in the market. The one that is fixed to the bone with a biological cement, and this is the cemented type of hip replacement. 

The other one is naturally fixed to the bone through a process where the body heals by itself; where new bone is formed over hills and valleys in the microscopic picture of the stem, and that will make it very solid and stable. This type of hip replacement is called an uncemented hip replacement.

How long does it take to dry? Can bone cement be removed?

The cemented type of hip replacement, when we insert it using biological cement, usually solidifies in around 11-12 minutes and becomes very hard afterwards. It allows a certain creeping, which is relaxation and constant load to accommodate the new stem over the next few months. That process will allow this to be very well fixed to the bone. 

It's worth mentioning that the cement can be removed at any stage after surgery; we have special instruments to use; we have ultrasonic machines that transforms it from a liquid phase to a solid phase, and can be easily removed. 

How long do both types of hip implant last? Which hip implant is best, cemented or uncemented?

We've had a lot of date since 2005 about the longevity of both cemented and uncemented hip systems. There are excellent reports supporting both systems lasting for more than 20 years. 

There's no preference for which one to use; usually in a younger population, less than 50 years old, we usually use an uncemented hip replacement. In a population of 70 years and above, we use a cemented hip replacement. 

Between 50 and 70, it depends on the activity level, and there are comorbidities that the patient has which makes us choose one or another. For both, they have excellent results and there's no one better than the other. 

If you’re looking for gold-standard hip replacement surgery, arrange an appointment with Mr Awad via his Top Doctors profile