Genes play role in success of hip replacement surgery

The success of hip replacement surgery could depend partly on your genes, a new study suggests.

People with mutations in genes that helpbreak down collagen and generate vitamin D were more likely to have complications after surgery, British researchers found.

Dr. Hammad Malik of the University of Manchester and his team analyzed genetic variations in 312 people, including 162 patients who had problems in the 10 years after their surgery.

Ninety-one of the complications were loosening of the joint, known as asceptic loosening. Another 71 were infections, the researchers said in Thursday's online issue of the journal Annals of Rheumatic Diseases.

People showing a variation in the MMP1 gene, which breaks down collagen, were three times as likely to show asceptic loosening. Collagen is the main protein in bone and cartilage.

Those with infections caused by bacteria in the implant were almost twice as likely to have mutations in a gene that aids the synthesis of vitamin D. The vitamin is important for strong, healthy bones.

Variations in a third gene, interleukin 6, which is involved in bone metabolism and immune response, did not appear to have any effect.

If the results are confirmed by further research, the findings could be used to predict the long-term success of hip replacements and help develop genetic treatments to prevent loosening of implants, the researchers concluded.

In 2004-2005, 58,714 patients received hip or knee replacements in Canada, compared with 53,517 procedures the previous year, according to the Canadian Institute for Health Information.