- This study evaluated 228 patients who underwent revision THA for osteolysis without component loosening: 124 who underwent acetabular and/or femoral component revision and 104 who underwent isolated bearing exchange
- 12.1% of revisions failed in the component revision group versus 9.6% in the isolated bearing exchange group; the survival rates on Kaplan-Meier analysis were 85% and 82%, respectively
- In both groups the main reason for failure was aseptic loosening; rates of loosening did not differ significantly between the groups
- Renal disease was the only risk factor associated with failure of isolated bearing exchange
- At latest follow-up in the isolated bearing exchange group, there was no progression of osteolysis
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One of the common causes of failure in total hip arthroplasty (THA) is aseptic loosening secondary to periprosthetic osteolysis. In turn, the most common cause of osteolysis is acetabular polyethylene liner wear because microparticles induce a phagocytic immune response.
In cases where the femoral and acetabular components are well fixed, there is no consensus about how surgeons should proceed. Revising well-fixed components might result in significant blood and bone stock loss, but exchanging the polyethylene without acetabular cup revision might increase the risk of subsequent component loosening.
Wenhao Chen, MD, research fellow at the Bioengineering Laboratory in the Department of Orthopaedic Surgery at Massachusetts General Hospital, and Young-Min Kwon, MD, PhD, program director of the Adult Reconstructive Surgery Fellowship Program and director of the Bioengineering Laboratory, recently compared the two approaches. In The Journal of Arthroplasty, they report comparable re-revision rates and survivorship for component revision and isolated bearing exchange.
Using a prospectively maintained database, the team identified 228 consecutive patients who underwent revision THA for osteolysis without component loosening. 124 patients underwent acetabular and/or femoral component revision and 104 underwent isolated bearing exchange with allogenic bone grafting. All revision surgeries were performed between 1999 and 2016. The average follow-up time was five years (range, 4–10).
Failure of the revision surgery was defined as re-revision for any reason. 12.1% of revisions failed in the component revision group versus 9.6% in the isolated bearing exchange group (P = NS). There was no significant difference in failure rates between patients revised for acetabular versus femoral osteolysis.
Causes of Failure
In both groups, the main causes of failure were component loosening and dislocation. Less frequent causes were fracture or periprosthetic joint infection. There were no significant differences between the two groups with respect to any cause.
Risk Factors for Failure
Univariate analysis demonstrated that renal failure was associated with the failure of isolated bearing exchange. Revision type (component revision vs. isolated bearing exchange) was not a risk factor for failure.
After 10 years, the survival rate according to Kaplan-Meier analysis was 85% for component revision and 82% for isolated bearing exchange (P = NS).
Applying the Results to Practice
At the latest follow-up in the isolated bearing exchange group, there was no progression of osteolysis on radiographs. This suggests removal of the polyethylene is important in preventing treatment failure.
However, surgeons should exercise caution when managing osteolysis in THA patients with renal failure as renal failure was associated with the failure of isolated bearing exchange.
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