Hip replacement is one of the regularly performed orthopedic procedures. It involves substitution of an artificial ball-and-socket joint for the hip joint. It is carried out to address a persistently painful and stiff hip, a fracture that did not heal or joint degeneration. A portion of the shaft together with the femoral head and neck are removed and replaced with a prosthetic implant during the procedure.There are different implants available in the market, each are manufactured using different materials. An example of this is the metal-on-metal implant which utilizes cobalt-chromium alloy from the head down to the shaft. The reports on DePuy hip recall symptoms made DePuy Orthopedics issue a voluntary recall on their metal-on-metal implant a few years after it was released in the market.

What then is a metal-on-metal hip implant?

Metal-on-metal (MoM) hip implants consist of a ball, a stem and a shell, all made of metal. It is more suitable for younger and physically active individuals because the durability of the metal implant can last for years. With MoM implants, greater range-of-motion is possible and a decrease chances of dislocation because of its larger femoral heads. Based on the record of Nationwide Implant Sample database, there are about 39,200 MoM hip replacements performed in the year 2005-2006. Evaluation and test for compatibility of metal-on-metal implants are done by FDA through their 510(k) program.

One concern on this implant is the long-term frictional release of cobalt or chromium ions from the joint despite its low wear rates.The concentration of this ions in the body increases overtime which may eventually end up in metallosis. A case report of the Journal of Bone and Joint Surgery showed 2 patients complaining of adverse reactions after receiving MoM total hip replacements. Cobalt toxicity manifestations following the procedure were observed on these patients.

There is no universal agreement as to what is the perfect hip implant. It is therefore important to undergo a thorough assessment and evaluation with a health care provider and discuss the pros and cons of each hip device. A metal-on-metal hip implant has both advantages and disadvantages. Therefore, it is important that you consult your health care provider for inquiries about hip devices and you both agree on a certain a implant that will benefit you most.This will minimize, if not prevent, untoward effects like a DePuy hip recall.