WHICH TOTAL HIP MODEL

&

Which surgeon

The art to choose the right total hip model

and

the right surgeon

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A study found that English surgeons currently are using  sixty-two different models of  total hip implants,  produced by twelve manufacturers. For the majority of these models there has been no evidence about their efficacy. The prices ranged between 250  to 2 500 £ (160 to 1600  $), some of the cheapest models had the best results. In several other countries the number of total hip models is even greater. (Murray 1995)

So how you should proceed before you decide which type of a THR you should have?  Be informed before you make a decision. There are several facts you ought to know.

• Not all total hip prostheses are created equal. There is a great difference in their design, individual surgeons or "schools of surgeons" have their special philosophy about  the construction of a successful total hip prosthesis

• Different manufacturers use their special materials  which the company developed and patented for manufacture of their models of total hip prostheses. Although all these materials conform to international standards, there are small, but sometimes   important differences among them.

• Not all models of total hip prostheses perform alike. Many models once introduced onto the market were not successful.  Some of them caused catastrophic rates of failures. For example,  60 % of the  total hip operations done with a once highly acclaimed  hip prosthesis failed, causing severe problems to the patients. (Swedish hip registry)

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WHICH SURGEON IS THE BEST ?

Actually, although this is one of the most often asked questions, it has no clear answer. There are, however, some facts that may help you.

• You should be informed about

• the performance of the total hip prosthesis which is recommended to you;
• about the performance of the surgeon who will carry out the operation; 
• about the performance of the hospital where the operation will be performed.

There is no universal agreement as to which design of a total hip prosthesis is best. Each surgeon selects what he believes is the best model, the model he was trained to use.

The most important consideration is that your surgeon should be totally comfortable and familiar with the surgical technique for implantation of the total hip prosthesis he / she selected for you. Each model of the total hip prosthesis needs unique operation technique and experience with unique instruments  used with the operation. This technique can only be learned by experience with operations on many patients.

Studies demonstrated that surgeons who perform low numbers of total hip operations have had more postoperative complications in their patients. (Editorial 2001)

Hospitals  with low numbers of total hip operations have had higher mortality rate after these operations.

WHICH  MODEL IS THE BEST?

The results of total hip replacement depend on many factors, but only one of these factors is the model of the total hip joint. There has never been any understanding among the surgeons which total hip model is best.

Many health authorities, however, use a "benchmark" for evaluation of the models of total hip joints.

One such benchmark is the rate of failure ten years after the surgery:

less than 10 % of total hips failed during a ten years period.

Nobody, neither the manufacturer, the surgeon, or the patient, not to speak about the FDA, is willing, however,  to wait ten years before the new total hip model will be released for general use.

So another benchmark is  less than  3,3 % of failed total hips during a  three years period.

For more information, visit also the chapters

Conventional total hip

Ceramic total hip

Metal on metal total hip

Cemented and cementless THR

Questions to ask your surgeon:

• What are the clinical results of this total hip implant you have chosen for my hip replacement operation?
• How can I be sure that I’m getting the best available total hip implant?
• Were the results of this total hip implant published? May I read  about the results?
• What are your personal clinical results with this  total hip implant?  Do you have a personal register about the results? How long back does this register reach?
• What, in your opinion, makes this implant the very best implant available for use in just my case?
• May I discuss the results with other patients, operated on by you? 

Remember that

• Results achieved with total hip prostheses in laboratory experiments are no substitute for results achieved on the  living patients.
• Total hip models constructed according to the armchair philosophy failed in the past.

  For more information about these questions  www.biomet.com/patients/bestimplant.html

See also the chapter  Asking your surgeon

      TYPES  OF  TOTAL  HIP PROSTHESES

For better orientation I divided the currently used total hip prostheses according to the materials used for their joint surfaces into

• conventional  (metal ball on polyethylene cup)
• metal-on-metal, (metal ball on metal cup)
• ceramic (ceramic ball on ceramic or polyethylene cup) .

   Every total hip prosthesis must be fixed to the  skeleton by one of the following methods:

•   cemented total hip = the prosthesis is secured to the skeleton by a substance called  bone cement
•    cementless total hip - the prosthesis is directly impacted into the skeleton and secured by a (successive) ingrowth of the bone into the surface of the prosthesis.

For more information select please from the chapters below