Joint RePlacements

The majority of joint replacements performed are hip and knee replacements. Less commonly required joint replacements include shoulder and elbow replacements.

The specific prosthesis/implanted joint used in a replacement depends on a variety of factors, such as the underlying disease process (for example osteoarthritis, rheumatoid arthritis, post-traumatic arthrosis, avascular necrosis etc), the age of the patient, the body weight, the radiological assessment, the clinical assessment, the expected wear-and-tear on the prosthesis and the expected longevity of the prosthesis.

Prostheses vary widely in design as well as pricing. The most expensive system on the market costs approximately four times the amount of the least expensive. Therefore, to a certain extent we can utilize the best prosthesis that the patient can afford. We only use prostheses that have a well established track record and which have been well documented in orthopaedic literature.

As mentioned, the prosthesis is selected for each patient depending on their individual requirements. However, the system that we use most commonly for hip replacements is a combination of a Synergy uncemented stem and a Reflection uncemented acetabular cup, both produced and marketed by Smith and Nephew. When using cemented prostheses we use either a Spectron stem (Smith and Nephew) or a Charnley C-Stem (De Puy), which we all hope represents the next step forwards in stem design. It has been touted as the "30 year stem" by Professor Wrobleski, who is the designer and successor to Professor Charnley at Wrightington Hospital. By this he expects the stem to last 30 years after being successfully implanted.  

Another system that we use, for the appropriate patients, is the Birmingham Hip Resurfacing (BHR) / McMinn prosthesis, marketed in this country by Smith and Nephew. This is a resurfacing rather than a total hip replacement, and despite the fact that the long-term (10-20 years) results have yet to be

published, it is showing immense promise for becoming the gold-standard in hip replacement surgery in young patients.

The system I use most commonly for knee replacements is called a Genesis 2, manufactured and marketed by Smith and Nephew (Memphis, USA). This includes the new Oxinium components, which show an 85% reduction in wear when compared with standard Chrome-Cobalt components. Recently we started using the Journey prosthesis for younger active, more sporting patients. Golfers particularly do very well with this knee.

Both De Puy and Smith and Nephew have long track records, with many published articles in the orthopaedic literature supporting their claims as the 2 top manufacturers of orthopaedic implants worldwide.

Anaesthetics

The most common anaesthetic provided for either a knee or hip replacement is a combination of the following: For the procedure a general anaesthetic or a spinal anaesthetic is performed, depending on the specific patient and their medical condition. For post-operative pain relief an indwelling epidural catheter is placed prior to the operation. This allows the patient to be completely free of pain for the vitally important first two to three days following the operation. It also means that the need for heavily sedating analgesic medications is almost entirely avoided. Although pain free, the patient is still able to move their legs and even walk – the so-called "walking epidural".

The policy in prevention of deep vein thrombosis is to utilize 4 modalities: physiotherapy, thrombo-elastic (TED) stockings, enoxaprin/delteparin daily and intermittent calf pump treatment.