Thursday, July 5, 2012

An Expert Explains the Failure of Metal-on-Metal Hip Implants

I recommend watching this British Medical Journal video interview of Dr. David Langton, a Researcher Fellow and orthopedic surgeon from Newcastle University. Dr. Langton has won numerous awards and accolades related to his engineering research on failed metal-on-metal hip joints, including the Smith & Nephew Birmingham hip, the DePuy ASR and the DePuy Pinnacle hip implant systems.
In this video, Dr. Langton discusses the safety of metal-on-metal hips (specifically the DePuy ASR) and his findings after studying all metal hip replacements, for the past three years under Dr. Antoni Nargol, in pursuit of his Ph.D.
He states the long-term systemic effect of cobalt metal toxicity is unknown; however some studies show cognitive related issues. The main concern is the localized effects of the metal ions in the hip cavity; cobalt and chromium metal ions concentrate in hip fluid and can cause soft tissue and bone damage around the hip joint. Additionally, the metal particles get in the blood stream, and medical studies conclude it can cause rashes and headaches. Most patients with a metal-on-metal device have hip and groin pain while some suffered femoral fractures. Even though women typically have a quicker response to cobalt, it is necessary for all recipients of an all-metal hip to obtain a cobalt and chromium blood test.








Dr. Antoni  Nargol, a consultant orthopaedic surgeon at the University Hospital of North Tees, worked on the study that DePuy submitted to the F.D.A. and later became a critic of the DePuy ASR. Dr. Nargol told the New York Times in February 2012 “that [DePuy] had never informed him that its application for approval [of the recalled DePuy ASR XL] in the United States had been rejected.” 
Langston says that revision surgery shows a puss like fluid in the joint and some [doctors] say it’s an infection opposed to an adverse local tissue reaction to cobalt.

“I would definitely advise against anyone, at the moment, having a large diameter total hip replacement.”  - Dr. David Langton