Abdel, MP

Introduction Infection following extensor mechanism reconstruction with Marlex mesh is a devastating and limb threatening complication. The purpose of this study was to evaluate whether vancomycin-loaded mesh reduced staphylococcal infection in a murine extensor mechanism reconstruction model with Marlex mesh. Methods Mouse-sized, eight-layer Marlex mesh constructs were fabricated to simulate clinical reconstruction and soaked in a vancomycin solution (50 mg/mL) for in vitro and in vivo testing. Three methicillin-resistant clinical isolates from human periprosthetic knee infections were evaluated: Staphylococcus aureus, Staphylococcus epidermidis , and Staphylococcus lugdunensis. In vitro testing assessed vancomycin loading, mechanical properties, antibacterial activity, and early biofilm inhibition. For in vivo experiments, plain or vancomycin-loaded Marlex meshes were implanted into the murine extensor mechanism and inoculated intraoperatively (5 per group per isolate). Meshes and surrounding tissues were harvested on postoperative day 9 for quantitative culture. Results For all three isolates, vancomycin-loaded Marlex mesh exhibited sustained antibacterial activity for up to 3 days in vitro based on zone of inhibition testing (days 1–3, p < 0.0001 for each isolate). In vitro testing of biofilm inhibition demonstrated significant reduction in biofilm-associated colony-forming units at 6 hours after inoculation and remained low thereafter (p<0.05 for each isolate). In vivo , vancomycin-loaded Marlex mesh reduced bacterial burden on meshes and surrounding tissues by > 3 log₁₀ compared with plain mesh for all three isolates (p<0.01 for both mesh and tissue for all isolates). Conclusion Vancomycin-loaded Marlex mesh provided sustained local antibacterial activity and significantly reduced staphylococcal infection without compromising mechanical properties in a murine extensor mechanism reconstruction model. This approach may represent a promising adjunct to reduce infection risk in extensor mechanism reconstructions with Marlex mesh after total knee arthroplasty.

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.