Design of an electrospun wrap for improved durability and infection control in Masquelet’s induced membrane technique

Masquelet’s Induced Membrane Technique is a promising treatment method for large and infected bone defects. However, the procedure is plagued by an 18% revision surgery rate due to inadequate membrane formation, limited membrane durability, or persistent infection that impact bone formation and consolidation. Herein, we designed an electrospun wrap to be placed around the cement spacer during the procedure to augment membrane durability and provide sustained infection control. A range of electrospun polycaprolactone wraps were examined to identify the fiber diameter with the desired balance of cell infiltration and mechanical properties. A 5 μm fiber diameter was shown to maintain the International Organization for Standardization (ISO) suture retention standards (>2.0 N) and facilitate full thickness cell infiltration within 4 weeks. Gentamicin was loaded into the fibers and maintained a released dose above the minimum bactericidal concentration for 8 weeks with a zone of inhibition study demonstrating no loss of antimicrobial activity from electrospinning. Lastly, a subcutaneous rat study was performed to evaluate the effect of the antibiotic-loaded fiber wrap on induced membrane formation. After 6 weeks, the induced membrane was integrated throughout the full thickness of the wrap with no observed effect of the antibiotic release on membrane formation. The suture retention strength of the wrap-membrane composite was substantially improved (2.42 ± 0.45 N) over the induced membrane control (0.46 ± 0.06 N). Collectively, these findings demonstrate the efficacy of an electrospun wrap to structurally-reinforce the induced membrane while providing sustained antibiotic release.