How to ensure you get the hip replacement that best suits you
Replacement Hip replacement - arthroplasty - may be a routine operation, but it should not be a one-size-fits all procedure. We examine today's choices in hip replacement technology.
Hip replacements have come a long way since they were first developed and remain one of the most successful medical procedures. Today joints come in a range of materials, but the newest or most expensive are not always the best choice.
"Patients often ask for the newest technology but hips have to last 20 to 30 years, so the best choices balance the latest technology with a proven track record and take into account the individual patient," says consultant arthroplasty surgeon Professor Edward T Davis, Director of Research and Development at The Royal Orthopaedic Hospital NHS Foundation Trust.
Hips are ball and socket joints so replacement joints consist of a cup to replace the natural socket and a ball replacing the natural ball of the femur. The most commonly used in the UK today are those with a metal ball and a polyethylene ('poly') lined cup. Second come all-ceramic joints, and third those with a ceramic ball and poly cup.
Data from the Australian Joint Registry show that after ten years ceramicised metal on poly joints require revision (replacement) in 3.3 per cent of cases; for metal on poly the figure is 4.3 per cent; ceramic on poly is 4.6 per cent and ceramic on ceramic 5.1 per cent.
"The latter is the most expensive so spending more does not guarantee the best outcome," says Davis.
Davis' research of data from the National Joint Registry of England, Wales and Northern Ireland shows the same trends.
The poly also makes a difference, he says. "Cross-linked poly, where the material has been modified, appears to be more wear-resistant, so a ceramicised ball with a cross-linked poly-lined cup looks a good option."
The use of cement is also an issue. A majority of hip replacements in the UK are uncemented - the pin is hit into a cavity in the femur and secured by bone growth. Where cement is used it releases chemicals into the bloodstream, in rare cases causing deaths.
"Cement may be a good choice where the bone is thin as hitting the joint into the cavity risks femur fracture," says Davis. He is unimpressed by recent Department of Health advice suggesting that cement should be used as often as possible, to save money.
Davis also advocates the use of computer technology to ensure accurate placing of the joint and to get leg lengths right, which tends to make for better outcomes.
Overall, he insists: "No one material or procedure suits everyone. The choice should be based on the individual patient."