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Highly porous metal acetabular augments may provide structural support in complex revision THA
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ORLANDO, Fla. — While highly porous metal acetabular augments are not used frequently, the use of this fixation method with uncemented acetabular components during complex revision total hip arthroplasty can provide structural support against the host bone, according to a speaker here.
“With failures that can tend to occur when you have irregular defects that you cannot fill with a hemisphere or an associated pelvic dissociation, these augments were designed as a prosthetic structural allograft,” David G. Lewallen, MD, said at the Current Concepts in Joint Replacement Winter Meeting.
Lewallen and his colleagues selectively used porous tantalum acetabular augments in 85 patients who underwent revision total hip arthroplasty (THA) out of 1,789 revision hip patients between 2000 and 2007. Of these patients, 58 patients were followed up for at least 5 years.
“We looked carefully to see if we were able to restore the mechanics of the hip. It was not perfect, but it was much better than we have achieved with other techniques at restoring the hip to its anatomic location” Lewallen said.
Cases that had failed or were at risk for failure were patients with pelvic dissociation. A better solution or adjunctive fixation was needed for these patients, he noted.
The use of porous metal acetabular augments provided a stable interface and secure fixation with overall survivorship of 91% at 10 years.
“This technique can allow for the avoidance of structural bone grafting for even the most massive of bone defect problems, but additional follow-up is needed to see how durable these encouraging results are over the longer term,” Lewallen said.
Overall, Lewallen said he believes this technique has been helpful to have highly porous metals for enhanced ingrowth, but it is more important how these materials are used rather than the specific characteristics of these materials.
“Being able to get lots of screws and then cementing liners to lock those screws in place has been a useful tool for us to maximize [results], but you have to get lots of screws in these cases,” he said. – by Nhu Te
Reference:
Lewallen D. Paper #57. Presented at: Current Concepts in Joint Replacement Winter Meeting; Dec. 14-17; Orlando, Fla.
Disclosure: Lewallen reports he is a stockholder for Acuitive; receives stock for consulting from Ketoi Medical Devices; receives royalties for implant design and has intellectual property with Stryker and Zimmer; and receives a consulting fee from Waldemar Link GmbH & Co., KG and Zimmer.