184 REVISION TOTAL HIP ARTHROPLASTIES FOR PELVIC DISCONTINUITY: ADVANCEMENTS WITH CUP-CAGE AND CUSTOM TRIFLANGE CONSTRUCTS

Introduction Historic series have demonstrated the importance of construct rigidity in the treatment of pelvic discontinuities, but there remains limited data comparing different constructs, especially contemporary cup-cages and custom triflange components. The aim of this study was to evaluate reconstructive constructs with emphasis on implant survivorship, radiographic results, complications, and clinical outcomes. Methods We reviewed 184 revision THAs with unilateral pelvic discontinuity at a single institution between 1998–2022. Mean age was 66 years, 83% were female, and mean BMI was 29 kg/m2. Constructs included uncemented cup and plating (n=66, 36%), cup-cages (n=59, 32%), jumbo uncemented acetabular components (n=30, 16%), conventional antiprotrusio cages (n=16, 9%), and custom triflanges (n=13, 7%). Since 2013, 73% of cases were treated with either a cup-cage or custom triflange. Acetabular distraction (n=36, 20%) and porous augments (n=33, 18%) were used as adjuncts. Mean follow-up was 8 years. Results The 5-year survivorships free of revision for aseptic loosening, any revision, and any reoperation were 92%, 79%, and 75%. Of 43 revisions, the most common indications were aseptic loosening (n=15) and dislocation (n=15). For each construct, the 5-year survivorships free of revision for aseptic loosening were 100% (triflange), 94% (cup-cage), 92% (uncemented jumbo acetabular component), 90% (plating), and 86% (conventional anti-protrusio cage). Radiographic analysis demonstrated discontinuity healing in 85% of unrevised patients. Of the 15 re-revisions for aseptic loosening, 92% involved loss of fixation from inferior hemipelvis. There were 63 complications with dislocation (n=32), nerve palsy (n=10), and wound problems (n=9) most common. Mean Harris hip scores improved from 51 to 70 at 5 years. Conclusion In this series, the 5-year survivorship free from aseptic loosening was very good (92%), especially with contemporary techniques like custom triflange (100%) and cup-cage constructs (94%). Survivorship free from any revision (79%) and reoperation (75%) remain lower due to dislocation and infection.