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Noted surgeon: Also follow patients with small diameter MoM heads for ARMD
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DALLAS — Although some surgeons have looked to the use of smaller heads to circumvent the potential for adverse reactions to metal debris in metal-on-metal total hip arthroplasties, a minimum 2-year follow-up on the use of 28- and 32-mm titanium modular acetabular components with chromium-cobalt tapered inserts cautions surgeons to closely follow metal-on-metal patients with small diameter heads as well.
“We should say that unlike the large diameter where we had aseptic loosening or failure of ingrowth as an early mode of failure, we did not see that with this titanium implant,” Adolph V. Lombardi Jr., MD, FACS, president of Joint Implant Surgeons Inc., said during his presentation at a recent meeting. “What we did see, however, is the development of adverse reaction to metal debris later on that represented 67% of revisions we did in this series and we have discontinued use of metal-on-metal bearings in our practice.”
Lombardi and his colleagues followed 258 patients (300 hips) with a mean follow-up of 10 years. The average patient age was 56 years. Head size was 28 mm in 71% of patients and 32 mm in 29% of patients.
Adolph V. Lombardi Jr.
Hip scores improved postoperatively and there were no dislocations. Of the 18 hips in 17 patients that were revised, two were for infection, four were for aseptic loosening or failure of ingrowth and 11 were for adverse reactions to metal debris (ARMD). “Component failure was more frequent in females and the activity level was not a risk factor for revision,” Lombardi said.
Adolph V. Lombardi Jr.ARMD had two general patterns with four hips presenting with pain, normal radiographs and elevated serum cobalt-chromium levels and six hips presenting with late, gradual onset of groin pain, weakness, subluxation and squeaking or grinding in the hips, while radiographs and infection serology appeared normal. Other ARMD revisions were one for femoral loosening associated with soft-tissue changes and one for acetabular fracture after falling with metallosis and bone loss. Researchers found an association between revisions in cases with mechanical symptoms with catastrophic pseudotumor and soft-tissue damage.
Lombardi told Orthopedics Today. “Our message is these patients need to be followed just like you are following your large head metal-on-metals.”
He and his colleagues plan to follow patients who underwent metal-on-metal (MoM) THA and counsel them on the possibility of having complications. Overall, Lombardi advocates stopping the use of MoM THAs in the future.
“Although [ARMD] has a low frequency, it can at times be a catastrophic complication. I think now that we have good 10-plus year data on highly crossed polyethylene and on ceramic and polyethylene, we know there are good alternatives,” Lombardi said. – by Casey Tingle
Reference:
Lombardi AV. Paper #49. Presented at: American Association of Hip and Knee Surgeons Annual Meeting. Nov. 6-9, 2014; Dallas.
For more information:
Adolph V. Lombardi Jr., MD, FACS, can be reached at Joint Implant Surgeons Inc., 7277 Smith’s Mill Rd., Suite 200, New Albany, OH 43054; email: lombardiav@joint-surgeons.com.
Disclosure: Lombardi receives royalties from, is a paid consultant to and serves on a speakers bureau for Biomet, the manufacturer of the device used in this study. His royalties from Biomet are for products other than the study device. His institution, Joint Implant Surgeons, receives research support from Biomet. In addition, Lombardi is a paid consultant and serves on a speakers bureau for Pacira and receives royalties from Innomed. Joint Implant Surgeons also receives research support from Pacira, Stryker and Kinamed.