Indication for Proximal Femoral Replacement Is Associated With Risk of Failure.

<bold>Background: </bold>Proximal femoral replacement (PFR) is reserved as a salvage procedure after failed total hip arthroplasty (THA) or after wide margin resection of tumors involving the proximal femur. Although failure of the PFR construct remains a significant problem, indication has not previously been investigated as a risk factor for failure.<bold>Methods: </bold>This study retrospectively evaluated patients who underwent PFR over a consecutive 15-year period for primary sarcoma or metastatic disease of the proximal femur, compared with conversion to PFR after failed THA. PFR failure was defined as recurrent prosthetic dislocations, periprosthetic fracture, aseptic loosening, or infection that ultimately resulted in revision surgery.<bold>Results: </bold>Overall, 99 patients were evaluated, including 58 in the neoplasm and 41 in the failed THA cohorts. Failed THA patients were older (P < .001), with a greater proportion having comorbid hypertension (P = .008), cardiac disease (P = .014), and history of prior ipsilateral and intracapsular surgeries (P < .001). The failure rate was significantly higher in failed THA patients (39.0% vs 10.3%; P < .001) with significantly shorter implant survivorship on Kaplan-Meier analysis (P = .003). A multivariate Cox proportional hazards model showed that THA failure was the only independent predictor for PFR failure (hazard ratio: 4.26, 95% confidence interval: 1.66-10.94; P = .003).<bold>Conclusion: </bold>This study revealed significantly worse PFR implant survivorship in patients undergoing PFR for the indication of failed THA compared with neoplasm. Although the underlying etiology of this relationship remains to be explicitly outlined, poor bone quality and soft tissue integrity, multiple prior surgeries, and comorbid conditions are likely contributing factors. [ABSTRACT FROM AUTHOR]