Issue: May 2015
Perspective from Laurent Sedel, MD
May 01, 2015
3 min read
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Ceramic-on-ceramic bilateral THA may result in fewer revisions than ceramic-on-poly hips

Issue: May 2015
Perspective from Laurent Sedel, MD
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There is a significant difference between the survivorship and number of revisions needed in bilateral total hip arthroplasty according to the type of material used when the procedure is performed with a different type of articulation in each hip, according to results of a study in which some patients were followed up for 30 years.

Philippe Hernigou, MD, professor of orthopaedic surgery at CHU Henri Mondor, in Créteil, France, is scheduled to present results of the study at the EFORT Congress in Prague this month.

He and colleagues compared the revision rates, survivorship, outcomes and complications for alumina ceramic-on-ceramic (AL) cups and polyethylene (PE) cups used on 32-mm ceramic femoral heads during total hip arthroplasty (THA) performed on both hips in the same patient. The anodized titanium alloy stem used in each case had a smooth surface and was cemented, and all implants were produced by the same manufacturer.

Philippe Hernigou, MD, PhD
Philippe Hernigou

The 60 patients studied were younger than 30 years old at the time they underwent bilateral THA and they all had a diagnosis of osteonecrosis.

Better ceramic-on-ceramic performance

Hernigou and colleagues found the AL cups implanted in procedures performed between 1978 and 1985 outperformed the PE cups in nearly every category.

“Considering the endpoint at 30 years, the survival of ceramic-on-ceramic hips was 75% without revision and 95% without two revisions. The survival with PE cups was 58% without revision and 70% without two revisions. Hips with PE bearing surfaces were approximately six times more likely to undergo two subsequent revisions before 30-years follow-up as compared with AL hips,” Hernigou told Orthopaedics Today Europe.

The study Hernigou and colleagues conducted is among the top papers scheduled to be presented at the EFORT Congress in Prague.

Revisions analyzed

At the 30-year follow up, 15 hips of the 60 AL hips required revision and three hips underwent a re-revision, according to Hernigou. For the PE cups implanted in the patients’ contralateral hips, 25 PE hips required one revision, 18 PE hips required one re-revision, and four PE hips underwent subsequent revision of a re-revision.

In addition, none of the AL hips developed osteolysis, but over the 30-year study period several PE hips developed osteolysis.

“With 30 years of follow-up, this series confirmed there is no osteolysis with AL/AL hips contrary to hips with PE friction where osteolysis increased with time. The poorer outcomes after revision surgery for patients with PE cups as compared with revision after ceramic hips revision could be explained by the more technically demanding procedure with osteolysis, the additional loss of bone stock and failures of allografts,” Hernigou said.

Complications with PE cups

The PE cups showed a higher dislocation rate than the AL cups, which was due to bone osteolysis and fatty muscle degeneration, according to Hernigou.

Hernigou and colleagues found CT scans could demonstrate reduced density in the muscles in the hip and this corresponded to fatty muscle degeneration, which in turn was associated with an increased incidence of osteolysis. The researchers could then use these factors to predict the patients’ risk of postoperative dislocation.

“Muscle fatty degeneration was more important on the PE side and associated with a higher rate of late dislocations on the PE side,” Hernigou said. – by Robert Linnehan

Disclosure: Hernigou reports no relevant financial disclosures.