Metal-on-Metal Hip Replacements 02/17/2011
The 2011 Kappa Delta Young Investigator Award was presented to Young-Min Kwon, MD, PhD, FRCS, FRACS, an orthopaedic surgeon at Massachusetts General Hospital, Harvard Medical School for his research titled, "Evidence-Based Approach in Understanding ‘Pseudotumors’ in Metal-on-Metal Hip Replacements."
His paper found that the five-year survival rate for young and active patients who undergo a metal-on metal hip resurfacing arthroplasty (MoMHRA) procedure is at 95 percent or above. However, a great deal of attention has been given to the failure of such devices, specifically with instances of soft tissue pseudotumors. Such complications are relatively rare, yet when they do occur are serious, causing local tissue destruction and often requiring corrective surgery.
For Kwon and his team, the goal of the study was to examine the unusual complications involving pseudotumors in patients with metal-on-metal hip replacements. "As a surgeon-scientist, it is critically important to investigate and gain insights into any unexpected complication that adversely affects patients’ outcome," said Kwon. "The best way to study these complications is to use an evidence-based approach which forms the foundations to provide clinical recommendations."
In his research, Kwon discovered:
•Pseudotumors were more frequent in women, increasingly so with women who had bilateral MoMHRA.
•Patients with pseudotumors had significantly higher levels of cobalt and chromium in their blood and joint fluid
From this research Kwon conducted a series of studies and concluded:
•Pseudotumors develop as a reaction to the metal debris that is generated from the wear of MoMHRA implants.
•The wear of these implants derive from edge-loading of the device – which damages the soft tissues of patients susceptible to pseudotumors.