FAQ

 Frequently Asked Questions:

There are now many different joint replacements on the market and your surgeon will be able to tell you exactly what your implant is made of. In terms of hips, often the part that goes into the femur is made out of metal. This may be a Cobal Chrome alloy or Titanium.

On top of the femoral implant will be the ball. This may be again made of metal or ceramic. On the acetabular, or socket side, the cup is made of a high density plastic sometimes in a metal socket. The bearing however may be made of metal or ceramic. Your surgeon will be able to tell you exactly which type of implant it is. For knees both the femoral and tibial side will be metal (normally Colbalt Chrome) and the insert which articulates between the two will be plastic.

The length of the incision depends on many things, including the severity of the arthritis, the size of the patient and the technique that the surgeon is using to do the surgery. The majority of hips will be done through an incision that ranges from 10 cms to 25 cms in length. The majority of knees will be done through an incision that ranges from 15 cms to 30 cms.

Yes, it is normal now at airports that the technology is so sensitive that it will pick up the metal within the hip or knee replacement and it is likely that the alarms will be triggered as you go through airport security.

Prior to the surgery and while rehabilitating after the surgery, you will be told of hip or knee precautions. These precautions are designed to help you get over the surgery safely without any complications occurring. The main complication shortly after a hip operation is dislocation and many of the precautions are a concern with this risk. Hip replacements can be done through different incisions and be of different types. Therefore each surgeon will develop a different set of hip precautions tailor made to his own surgery. Some surgeons using a particularly stable design of implant and approach to the hip may have very few precautions encouraging you to mobilise from crutches to sticks and a “normal lifestyle” as quickly as possible. Others may insist on a variety of precautions such as lying on your back in bed, not driving, not sitting on low chairs, not lying in the bath, not tying your shoes or putting your socks on, and using a raised toilet seat. It is therefore important to know your own tailor-made programme designed by your own surgeon.

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All hip and knee replacements aren’t the same and there are advantages and disadvantages for each of them. Your surgeon will be happy to discuss his choice of implant for you, explaining why he feels that this particular implant has benefits over others.

Similarly, all approaches to the hip and knee aren’t the same. Each of them have different advantages and disadvantages and each of them have different post-operative protocols to allow you to mobilise safely after the operation. Again your surgeon will describe the approach he uses and will be able to give reasons as to why that is the most appropriate for you.

There is a risk of developing deep vein thrombosis following joint replacement surgery, particularly if you have had problems with thrombosis in the past. The incidence of DVT is known to be high with joint replacement surgery and it is for this reason that all patients coming to joint replacement surgery will be considered for prophylaxis or prevention of deep vein thrombosis. There are many different ways that this can be achieved. Your surgeon may choose to use a mechanical method, a chemical method or a combination of both. The mechanical method involves compressing the legs intermittently to ensure circulation continues, possibly throughout the operation and certainly throughout the time that you are in bed afterwards. The chemical method usually involves injections just under the skin of a substance which will help thin the blood temporarily while you are at a high risk. You may also be asked to take Aspirin which also helps thin the blood and lastly, you may be asked to take Warfarin.  This is also a blood thinner and used particularly if you are at high risk. Your surgeon will have his own protocol for DVT prophylaxis and treatment and he will explain this to you.

You are usually in hospital for approximately five days. This may vary depending on local circumstances.

Most precautions are followed for a period of six weeks although your surgeon may want others to be followed for a period of three months. Doing your shoes up or getting out of the bath are particularly stressful for the hip and these may be activities that your surgeon would suggest not doing for three months.

In the past hip and knee replacement surgery was introduced and developed to get rid of the pain associated with arthritis. Advice after this would usually suggest a rather limited activity programme to protect the implant over the years. Many surgeons still follow this philosophy and although they will recommend you to be active, they will also recommend that you avoid high impact activities. With improvement in materials and modifications of technique, the expectation of surgeons and patients are now higher and many surgeons will encourage you back to all activities, including high impact exercise. This is something that you should discuss with your surgeon. If you think of the pre-operative work-up, the operation, and the early rehabilitation as being the first three stages, the long term maintenance and care of your joint replacement is important.

All surgeons have their own protocol for follow up but the maintenance of your hip or knee replacement should involve some long-term assessment with a clinical and radiological assessment. The frequency at which this occurs will be governed by several factors. Your surgeon will discuss this with you.

Failure of hip or knee replacement does occur and there are many possible reasons for it to fail. The aim of treating the failed joint replacement is to revise it to a fully functioning joint once more. This may involve using an implant which is different from the one originally used. In the majority of cases it is possible to achieve a successful second joint replacement. The way that this is achieved however depends on the cause of failure and prior to the hip revision you would be investigated to assess why the original replacement has failed and this may dictate how the revision is carried out.

During your pre-operative assessment and post-operative early rehabilitation, a lot of emphasis will be put on caring for your hip to prevent it dislocating. Dislocation occurs when the ball on top of the femur comes out of the socket within your pelvis. This is most likely to happen during the early post-operative phase when the soft tissues around the hip are not supportive. They are not supportive because any approach to the hip involves cutting the muscles or capsule into the hip joint. Some techniques of hip replacement surgery are more stable than others although there is a risk with every hip replacement. The advice that you are given in terms of mobilising after the operation will minimise the risk of it dislocating and as the soft tissues heal up, the risk becomes much less. If it does occur, and this is usually in the early post-operative phase, the usual course of events would be to have the hip reduced back into its proper position. This may require a general anaesthetic. It is followed by a period of immobilisation to allow the soft tissue to heal up around the joint replacement. Following this period of immobilisation you may be asked to wear a brace or corset of some sort to help maintain the hip in a good position. Usually however the dislocation will not occur and the hip will function well following the healing of the soft tissue.

If the dislocation becomes recurrent you may need to consider revision surgery but again this is something that your surgeon would discuss with you.