Cementing new liner into well-fixed acetabular component may yield durable fixation
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Cementation of a nonconstrained highly crosslinked polyethylene liner into a well-fixed acetabular component in revision total hip arthroplasty provided long-term survivorship with limited failures at the cement interface, results showed.
“We know the benefits of highly cross-linked polyethylene (HXPLE) in terms of wear and osteolysis,” Nicholas A. Bedard, MD, at University of Iowa, told Orthopedics Today. “But there is relatively limited long-term follow-up data evaluating this technique. We know [cementing a liner into an acetabular component] works in the short term. We also have biomechanical data demonstrating liner fixation with cement has similar mechanical stability to a standard locking mechanism, and so we wanted to see how well this technique worked 9 to 10 years after surgery.”
Bedard and colleagues at Mayo Clinic – Rochester analyzed 323 revision THAs in 320 patients (mean age of 63 years) from 2000 to 2008. All patients received a new HXPLE liner cemented into a previously implanted well-xed acetabular component. The most common indications for index revision THA were polyethylene (PE) liner wear and osteolysis (49%) and aseptic femoral component loosening (35%).
Long-term survivorship
At 10 years, survivorship free from re-revision was 80%, with survivorship free from reoperation of 77%. Overall, re-revision due to aseptic PE liner failure occurred in 11 hips (3%). Bedard and colleagues noted that in all 11 cases, the PE liner dissociated from the acetabular component and presented as a dislocation. They also noted 17% of cases had a dislocation, and instability was the most common reason for re-revision (45% of reoperations).
Upon univariate analysis, researchers found no significant association between patient and clinical variables and risk of re-revision or reoperation. However, hips undergoing revision for instability were “significantly more likely” to subsequently dislocate compared with hips undergoing revision for liner wear, they noted.
Expected risks
“We had a 17% dislocation rate, and so it is a concern, but it is also a known risk after revision surgery, and it is definitely multifactorial. A portion of the cohort was revised specifically for instability and, as such, their risk is going to be substantially higher for another dislocation,” Bedard said.
“An interesting finding to point out is that when non-neutral liners (elevated-rim or face-changing) were utilized, the risk of liner failure at the cement interface was significantly higher than when a neutral liner was used. Although it was only an association, I would be cautious cementing in non-neutral liners and potentially consider either revising the acetabular component or cementing in a different construct for those patients who are higher risk for dislocation,” Bedard said.
“If you encounter a well-fixed and well-positioned acetabular component, you can feel comfortable cementing in a HXPLE liner if the liner cannot be secured with the in situ locking mechanism,” he said. “In the long term, liner dissociation is not going to be a common failure mode for this technique. In our series, we had 3% in 10 years.”
- Reference:
- Bedard NA, et al. J Bone Joint Surg. 2020;doi:10.2106/JBJS.19.01441.
- For more information:
- Nicholas A. Bedard, MD, can be reached at 200 Hawkins Drive Iowa City, IA 52242; email: nicholas-bedard@uiowa.edu.
Perspective
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This study adds to the literature by demonstrating only a 3% polyethylene liner failure rate and a survivorship free from any revision of 80% at 10 years while including all indications for revision. Given these findings, surgeons can consider cementing noncompatible liners into well-fixed acetabular components when necessary, but must be mindful of the surgical indication, especially when addressing instability.
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