A comparison of dislocation risk between dual mobility and traditional constructs used in proximal femoral replacement.

Background: Proximal femoral replacement (PFR) is a reconstruction technique after tumor resection or for revision of failed total hip arthroplasty (THA). However, despite acceptable long-term oncologic and functional outcomes, extensive soft tissue or bone loss increases the risk for prosthetic instability. Instability may depend on the construct chosen for reconstruction, with current options including bipolar, constrained, or dual mobility implants. Clinical studies comparing patient outcomes after PFR with these three different constructs are limited. Methods: This study retrospectively examined a single tertiary academic institution's experience with PFR over a fifteen-year period. The medical records of patients who underwent PFR for indications such as tumor and failed THA with bone loss were reviewed. Patients were stratified into cohorts based on use of bipolar, constrained, or dual mobility implants. Patient demographics, disease characteristics, perioperative data, and data on prosthetic dislocations were recorded. ANOVA and chi-square testing was performed for continuous and categorical variables, respectively. The threshold for statistical significance was set to p < 0.05. Results: 106 patients were identified who underwent PFR. 46 underwent PFR with bipolar prosthesis (follow-up: 20 ± 24.57 months), 42 with constrained liner (follow-up: 30.45 ± 35.32 months), and 18 with dual mobility (follow-up: 15.38 ± 15.67 months). Only BMI (p = 0.036) and smoking history ( Conclusion: While study numbers are low, mean time to dislocation was significantly longer with dual mobility. Additional large-scale longitudinal studies are needed to fully elucidate the differences in outcomes amongst these three treatments.