Metastatic disease around the acetabulum often leads to patients needing total hip arthroplasty (THA), plus supplementary acetabular reconstruction. Traditional methods such as the Harrington reconstruction technique have shown good short-term outcomes, but there are concerns that a cemented acetabular component in this setting is at risk for failure in the longer term. Newer approaches, such as using cementless tantalum acetabular components with augments, have also shown promise. Houdek et al. compared these 2 approaches and report the findings in the July 15, 2020 issue of The Journal.
The authors followed 115 patients who underwent THA for metastatic disease at 2 tertiary sarcoma centers, with a mean 4-year follow-up among surviving patients. They compared the outcomes of 78 Harrington reconstructions with those of 37 tantalum reconstructions, with surgeons at each center exclusively performing 1 of the 2 techniques. The cohorts were comparable at baseline regarding age, sex, severity of systemic disease and acetabular defects, and pelvic discontinuity. Functional outcomes improved in both groups, but there were no significant between-group differences. The main statistical finding of the study was that a higher percentage of patients in the Harrington reconstruction group (27%) needed a reoperation than those in the tantalum group (8%), with a hazard ratio of 4.59 (p=0.003).
Historically, there has been an understandable lack of long-term follow-up in this fragile patient population; 94 of the 115 patients in this study died of systemic disease progression at an average of 16 months after surgery. Overall patient survival was only 34% at 2 years and 15% at 10 years. Despite these grim mortality numbers, Houdek et al. claim that with advances in treatments for metastatic cancer, patients are living longer and therefore may benefit from more durable acetabular reconstructions.
This study leaves unanswered the question of whether the theoretic advantage of bony ingrowth with tantalum is what accounted for the decreased reoperation rates. As Albert Aboulafia, MD notes in his Commentary on this study, the authors did not review radiographs or postmortem histology to look for evidence of osseointegration. But Houdek et al. do present a potential avenue for further investigation. And what remains clear is that metastatic disease around the hip is a complex problem, and that we as surgeons should continue to investigate promising treatment strategies to improve patient outcomes (even if only palliative) and enhance biological fixation.
Click here for a 4-minute video in which co-author Matthew Houdek explains the rationale for this study.
Matthew R. Schmitz, MD
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