Smith & Nephew PLC is a global medical technology manufacturer headquartered in the United Kingdom. The metal liner in its R3 Acetabular Hip System was recalled on June 1, 2012, because it was associated with dislocation, infection and bone fracture. Now, the company's Birmingham Hip and Emperion Hip System are under scrutiny because of fractures caused by crevice and device corrosion as well as metal debris.
UK-based medical technology company Smith & Nephew manufactures joint replacement systems for hips, knees and shoulders. While implants make up a substantial part of their business, the company also manufactures products used to treat severe wounds, broken bones and sports injuries. In 2014, its worldwide sales were over $4.6 billion. Over the years, the company made innovative contributions to hip implant design, but some of its implants like the R3 Acetabular System with metal liner, Birmingham Hip and Emperion Modular Hip System are under scrutiny for early failure rates and fractures.
Despite advances in the technology used in its product line, not all of Smith & Nephew’s hip products have demonstrated such a high level of safety or success. The metal liner in its R3 Acetabular System was recalled on June 1, 2012, because it was associated with implant dislocation, infection and bone fracture that required revision surgery. Another problematic Smith & Nephew hip product — the Birmingham Hip Modular Head implant —was marketed overseas. Smith & Nephew warned doctors of the possibility of implant failure for the metal-on-metal components when people began experiencing pain and poor mobility.
Smith & Nephew’s Hip Replacement Products
Smith & Nephew manufactures hip replacement parts for several types of hip replacement surgery, including partial or total hip replacement surgery, resurfacing and revision surgery. Unlike traditional hip replacement surgery, in which the head of the thighbone (femur) and hip socket are both removed and replaced with synthetic parts, hip resurfacing does not replace the femoral head. Instead, the femoral head is trimmed, preserving the patient’s bone, and capped with a metal implant. The damaged bone in the hip socket is removed and replaced with a synthetic shell. Revision surgery is required when a person suffers complications from worn-out or faulty implants. This surgery requires more specialized tools, implants and techniques than the original hip implant surgery (primary surgery).
Hip Systems and Products
|ANTHOLOGY Primary Hip System||R3 Acetabular System|
|SYNERGY||EMPERION Modular Hip System|
|SPECTRON Hip System||ECHELON Primary Hip System|
|CONQUEST FX Femoral Hip Implant||TANDEM Bipolar and Unipolar Hip System|
|REFLECTION Acetabular Cup System||POLARCUP|
|BIRMINGHAM Hip Resurfacing System||Short Modular Femoral Hip System|
|Short Modular Femoral Hip System||ECHELON Revision|
|SLR-PLUS Revision Stem||REDAPT Revision Femoral System|
Smith & Nephew’s OXINIUM Hip Replacement Products
Smith & Nephew introduced its exclusive alloy, OXINIUM (oxidized zirconium), in 2003. Using a patented heating process, the surface of this metal takes on the wear-resistant properties of ceramic while retaining the strength of the zirconium metal alloy beneath. The company uses OXINIUM parts with highly cross-linked polyethylene (XLPE) plastic components in its VERILAST line of products for both hips and knees. Studies have shown that oxidized zirconium improves the durability of joint implants and does not fracture like ceramic. The company claims that its VERILAST line also reduces metal sensitivity to nickel as well as the release of metal ions and debris into the body. These harmful conditions are commonly associated with metal-on-metal (MoM) implants.
Smith & Nephew’s R3 Acetabular System
The Smith & NephewR3 Acetabular System is a modular hip implant system. This means that the surgeon can choose the individual components based on the needs of the patient. These components come in plastic, metal and ceramic. Smith & Nephew began marketing this system in Europe and Australia in 2007, and it was made available in the United States and the rest of the world in 2009.
Most hip implant systems have several components: the acetabular cup (also called a shell), liner, femoral head and stem. The cup replaces the acetabulum, or hip socket. The liner fits in between the cup and the femoral head. The R3 Acetabular System includes an acetabular cup made of plastic, metal or ceramic; a femoral head made of OXINIUM, cobalt chrome or Biolox ceramic; and a liner made of OXINIUM, metal, ceramic or XLPE plastic. These pieces can be combined with several types of stems, allowing the surgeon to tailor the system to the patient. The metal liner featured in the system is made of high carbide cobalt chrome (CoCr), which the company claims is designed to reduce wear rates and provide optimal friction reduction. In addition to the CoCr liner, the R3 system comes with a polyethylene (plastic) liner. Smith & Nephew’s design allows the liners to fit better in the cup, which ideally should enhance range of motion while decreasing the risk of loosening, nerve impingement and dislocation.
The R3 Acetabular System can be used to relieve a number of degenerative and traumatic injury hip joint problems. These include osteoarthritis, avascular necrosis (bone death), traumatic arthritis and a fractured pelvis. This system is designed to withstand an active patient’s lifestyle, and its larger femoral head sizes provide better range of motion, greater hip flexibility and more stability. The cup features a porous coating that is intended to enhance fixation and promote bone growth into the implant. Despite claims of superior design by Smith & Nephew, patients still report complications with the implants.
Problems with the R3 Acetabular System and Metal Liner Recall
Many of the problems associated with the R3 Acetabular System are caused when the optional metal liner interacts with a metal femoral head component. When two metal surfaces are used together, this type of implant is called a metal-on-metal (MoM) hip implant. These hip replacements are associated with higher than normal revision surgery rates and may present additional complications like metallosis (metal poisoning) that stem from metal particles entering the body.
On June 1, 2012, just five years after its initial release, Smith & Nephew recalled the metal liner option of the device, citing higher than normal revision surgery rates and performance levels that were not acceptable. Smith & Nephew said the voluntary recall was a precautionary measure, but data had already documented problems with the R3 Acetabular System. Since it was released, 7,700 patients received the metal liner and a number of these patients have already required revision surgery.
Problems with the Emperion Hip System
Smith & Nephew’s Emperion Modular Hip System is also under scrutiny for premature failure and fractures that lead to revision surgery. The Emperion hip stem is a titanium modular implant with several interchangeable parts. The stem is the part that surgeons insert into the thigh bone. These modular stems are becoming more popular because they allow surgeons to mix and match components to fit a wide variety of patients. But, the small crevices between parts can also cause problems. A study written by Stronach et al. in the January 2016 Arthroplasty Journal detailed the case of a 67-year old man whose Emperion hip stem fractured six years after implantation.
“The benefits of modularity come with the potential drawback of a combination of fretting and crevice corrosion at the modular junction, which may accelerate fatigue, crack initiation and ultimately reduce the hip longevity,” researchers wrote.
Another study published in the February 2014 issue of The American Journal of Orthopedics written by Dr. Rachel M. Frank and colleagues also detailed potential issues with modular hip stems like the Emperion. When used with another metal component, such as the Birmingham hip, “crevice and fretting corrosion as well as the potential effect of metal debris generated by [metal-on-metal] MOM articulations” can cause premature fractures and failure, study authors wrote.
Smith & Nephew Hip Replacement Lawsuit
Approximately 3,000 to 4,000 R3 Acetabular Systems were distributed in the United States between 2009 and the June 1, 2012 recall. People who received this recalled device may have legal options against Smith & Nephew to recover compensation for any pain or revision surgery costs incurred. Those who received the metal liner option in this device are encouraged to evaluate their legal options even if they’re not experiencing complications from the device.
This is not the first time Smith & Nephew has come under scrutiny for its medical devices. In 2007, the company paid $28.9 million to the U.S. Department of Justice for illegally paying surgeons to use their implants on patients. Smith & Nephew was forced to undergo 18 months of federal monitoring as well.