|Metal-on-metal implants are getting quite the bad reputation. Could a platform of easily cross-linkable diene-copolymers by DSM Biomedical offer an alternative?|
Let the litigation begin: This week, plaintiff litigation law firm Burg Simpson Eldredge Hersh & Jardine filed a class-action lawsuit in Ohio against DePuy Orthopaedics (Warsaw, IN) on behalf of all U.S. citizens implanted with the ASR XL acetabular head system. The lawsuit follows last month's voluntary recall of DePuy's metal-on-metal acetabular head system attributed to a high failure rate associated with the hip implant. In the wake of the recall and as the suits likely continue to roll in, what can medical device manufacturers learn from the DePuy debacle? Materials matter!
Metal-on-metal hip implants have drawn fire for years owing to their tendency to produce metallic ion debris generated by the friction of the two metal bearing surfaces. This metal debris has been blamed for inflammation of the tissue surrounding the implant, which can result in early implant failure, discomfort, and the subsequent need for risky revision surgery.
The DePuy recall, however, appears to be the culmination of frustration and outcry against metal-on-metal implant designs, which has been especially prevalent in recent months. Back in March, for example, Medtech Pulse highlighted how the New York Times addressed the complications associated with metal-on-metal designs in an article that brought the issue to the attention of the masses. Then in May, reports circulated that all-metal hip implants might also be linked to tumor formation.
Simply put: Evidence is mounting against metal-on-metal implants. Sure, they boast mechanical strength and biocompatibility, but faith in their design is floundering. And that doesn't bode well for other manufacturers of metal-on-metal hip implants.
Luckily, there are other proven options. As noted in MPMN's April cover story, "What's Hip in Orthopedic Implant Design," ceramic-on-ceramic and even an emergence of ceramic-on-metal systems seem promising. Tried-and-true metal-on-polyethylene bearing surfaces are among the most popular combination. Plus, materials specialist DSM Biomedical, for instance, is researching how to optimize materials for these applications. The company offers a platform of easily cross-linkable diene-copolymers, and claims to be the first one to apply the technique to UHMWPE. The platform minimizes the loss of critical properties that can occur during conventional cross-linking processes and uses significantly lower doses of radiation, according to the company.