No abstract

We sought to determine the impact of bacterial inoculation and length of exposure on the mechanical integrity of soft tissue tendon grafts. Cultures of Staphylococcus epidermidis were inoculated on human tibialis posterior cadaveric tendon to grow biofilms. A low inoculum in 10% growth medium was incubated for 30 min to replicate conditions of clinical infection. Growth conditions assessed included inoculum concentrations of 100, 1000, 10,000 colony-forming units (CFUs). Tests using the MTS Bionix system were performed to assess the influence of bacterial biofilms on tendon strength. Load-to-failure testing was performed on the tendons, and the ultimate tensile strength was obtained from the maximal force and the cross-sectional area. Displacements of tendon origin to maximal displacement were normalized to tendon length to obtain strain values. Tendon force-displacement and stress-strain relationships were calculated, and Young's modulus was determined. Elastic modulus and ultimate tensile strength decreased with increasing bioburden. Young's modulus was greater in uninoculated controls compared to tendons inoculated at 10,000 CFU (p = 0.0011) but unaffected by bacterial concentrations of 100 and 1000 CFU (p = 0.054, p = 0.078). Increasing bioburden was associated with decreased peak load to failure (p = 0.043) but was most significant compared to the control under the 10,000 and 1000 CFU growth conditions (p = 0.0005, p = 0.049). The presence of S. epidermidis increased elasticity and decreased ultimate tensile stress of human cadaveric tendons, with increasing effect noted with increasing bioburden.

Distal tibia fractures are complex injuries with a high complication rate and unclear guidelines regarding operative timing for reduction and fixation. A tibial plafond fracture, or pilon fracture, is a fracture of the distal end of the tibia, often associated with complex comminuted fragments and surrounding soft-tissue injury compromise. Appropriate management of distal tibial and pilon fractures remains a challenge and existing research proves current surgical approaches have poor clinical outcomes. We propose that primary hindfoot arthrodesis using a tibio-talar calcaneal nail may be used as a successful method for treating complex distal tibial and pilon fractures, notably in those with coexisting medical comorbidities (diabetes, neuropathy, dementia, and compromised soft-tissue). The overall perioperative complication rate in this high-risk cohort may be reduced given a lesser invasive method for fixation. We hypothesize that primary hindfoot arthrodesis using an arthroscopic preparation and tibio-talar calcaneal nail for periarticular ankle trauma is a safe and effective surgical approach with optimal fracture alignment and stability.