Common Causes and Preventative Tips
What are the signs of hip failure? Is the there anything we can do to prevent it?
It's often said that if a hip replacement patient spent the rest of their life in bed the chances are that they would never need to get their implant replaced - it would last them the rest of their life.
The truth is that all replacement hip replacements will eventually fail and the questions are really about "how" and "when" .
Causes of Hip Failure
- Aseptic loosening - this is where the implant becomes loose within the bone and can occur whichever method of fixation is used.
- Infection - a hip replacement infection is very serious and can occur at any time - even years after surgery. An infection may damage the bone structure.
- Breaks - either breaking the prosthesis or the bone in which it's held.
Ceramic hip replacements are more slightly likely to break then metal ones but even so the rate of failure due to breakage is very low.
- Metallosis - this is associated with metal on metal hip replacements. When the two metal surfaces rub together they shed minute metal particles which can destroy bone and soft tissue leading to loosening of the implant and other undesirable problems.
Factors that Contribute
No two hips are the same - after all they belong to different people with different life styles and have been put in by different surgeons with different levels of expertise and experience.
The main factors that contribute to hip replacement failure are: -
- Activity levels - the more active you are the more likely you are to wear out your new hip. This is particularly true if the activity puts stress on the hip joint itself so walking is better than running, and swimming is better than weight lifting.
- How well was the implant put in? In an ideal world it wouldn't matter which surgeon you saw as they'd all be equally skilled. But real life is different. Some surgeons are better than other - which unfortunately means some aren't so good. If you're implant is put in at the wrong angle (and this need only be a tiny bit off true) then it increases wear as the two surfaces rub together harder.
- What the implant is made of? Different types of material are used to make hip implants namely metal, ceramic and polyethylene (used for the cup side only) and they have different rates of wear with polyethylene (poly) wearing fastest and ceramic being the longest lasting.
There are a variety of different combinations possible such as metal on poly or metal on metal. It is now known that one of these combination, metal on metal, is particularly prone to fail and has recently resulted in the recall of over 90,000 hips - see the Depuy recall for more information on that.
- Infections - Avoid Them! - check your wound site regularly during the first few months post-op and contact your surgeon or primary health carer if there is any sign of infection (e.g. discharge, heat, swelling). Some surgeons, particularly in the USA advice taking prophylactic antibiotics if you are undergoing certain treatments that might introduce infection into your body. The most common example is dental work - including a clean up.
Delaying/Preventing Hip Failure
Here are a few tips
- Make sure your hip is put in by an experienced surgeon at a hospital that specialises in hip replacements. It has recently been shown that hospitals with a lower volume of hip patients have a higher rate of DVT (deep vein thrombosis)
- Be very cautious about agreeing to a metal-on-metal implant.
- Be careful how you exercise. Avoid any significant impact on the hip joint during exercise. Minimise any weight bearing. Instead try walking, swimming, aqua aerobics and cycling.
- Try to find out how much your surgeon is paid by the company whose hip replacement products he is using. It doesn't necessarily mean that he is less than honourable but it might give you pause for thought. In 2007 41 doctors received a over $1 million each in payments from hip implant manufacturers.. In total a staggering $114 million was paid out that year alone.