A recent study appearing in the online version of The Lancet warns of increased early failure rates for hip resurfacing implants. The study, conducted on behalf of the National Joint Registry for England and Wales, compared data from more 30,000 hip resurfacing procedures from April 2003 to September 2011.
Researchers analyzed the data to determine how many resurfacing implants failed within the first seven years and if femoral head size impacted failure rates. The data indicated that female patients who underwent resurfacing had an increased failure rate, up to five times higher than other bearing surfaces. Researchers also found that men of smaller stature had an elevated failure rate. Dr. Ashley W. Blom, Professor of Orthopaedic Surgery at The University of Bristol, headed the team of researchers and calls the failure rates “unacceptably high.” Blom explained, “Our findings show that resurfacings with smaller head sizes are prone to early failures, and in particular that resurfacing in women has much worse implant survival, irrespective of head size.” Dr. Blom recommended that resurfacing procedures are not undertaken in women.
Hip resurfacing, which is often used as an alternative to total hip replacement, allows for preservation of a patient’s thighbone. In a total hip replacement, a patient’s femoral head is removed and replaced, whereas in a hip resurfacing, the femoral head is covered with a cobalt-chrome metal cap. Total hip replacements have a variety of bearing options including metal-on-metal, metal-on-ceramic or metal-on-polyethylene, but hip resurfacings always contain metal-on-metal bearings. In recent years, metal-on-metal hip devices have come under increased scrutiny after studies have indicated the devices release metal particles into the bloodstream and can cause increased metal ion levels in the blood, metal sensitivity, bone deterioration, swelling, pain, and nerve and tissue damage.