No abstract

The increasing clinical incidence and host risk of open fracture-associated infections, as well as the reduced effectiveness of conventional antibiotics to treat such infections, have driven the development of new therapies for the prophylaxis of open fracture-associated infections. We investigated percutaneous supplementation of a natural cytokine (i.e. interleukin 12p70 or IL-12) at an open fracture site to reduce open fracture-associated infections. We also determined the efficacy of the combination therapy of IL-12 and conventional antibiotic therapy in the prophylaxis of open fracture-associated infections. An open femur fracture infection model was produced by direct inoculation of a clinical isolate of Staphylococcus aureus after creating a femur fracture using rats. The animals were assigned to one of four groups: no drug administration, percutaneous supplementation of IL-12, intraperitoneal administration of the antibiotic ampicillin, or percutaneous IL-12 in combination with intraperitoneal ampicillin. Animals were euthanized at post-operative days 6, 10, 14, and 21. Percutaneous IL-12 led to a reduction in infection at post-operative days 6 and 10. For the first time, exogenous IL-12 was found to have additive effects in the prevention of infection when combined with conventional treatment (i.e. antibiotic therapy). Combination therapy of ampicillin and IL-12 substantially reduced the infection rate at post-operative day 6 and also decreased the time needed for complete inhibition of infection. Therefore, exogenous IL-12, providing a mechanism of protection independent of antibiotic resistance, complements the routine use of antibiotics.

The goal of this study was to determine if the degree of lateral tibial plateau fracture depression on computed tomography (CT) images predicted the presence of lateral meniscus tears. The study group comprised 85 patients who sustained a lateral tibial plateau fracture and underwent open reduction and internal fixation by the same surgeon. Degree of plateau depression was measured in millimeters by CT. Operative reports were retrospectively reviewed to determine if the lateral meniscus tear was intact or torn at the time of surgery. Twenty-eight patients had a lateral meniscus tear noted at the time of surgery. No significant differences existed in gender, mechanism or energy level of injury, Schatzker classification, or type of fracture among patients with a lateral meniscal tear as compared to those without a tear. Patients with > or =10 mm of plateau depression had an eight-fold increase in risk of having a lateral meniscus tear compared to those with <10 mm of depression. Patients younger than 48 years had a four-fold increase in risk of having a lateral meniscus tear than older patients.This study demonstrated an association between the amount of tibial plateau depression and the likelihood of a lateral meniscus tear. These findings may be used to predict those who have sustained a tear of the lateral meniscus and to advise the surgeon to prepare for a repair. Further prospective studies using magnetic resonance imaging as a tool to evaluate the extent of soft tissue injuries in plateau fractures is needed.

Infection is an everyday problem in orthopaedics and is quite common in open fracture management. To study this process and provide a basis to prevent infection, we developed a model that includes trauma (blunt fracture in the fashion of Bonnarens and Einhorn), surgical stabilization (standardized intramedullary K-wire fixation), and infection (Staphylococcus aureus inoculum). In this two-part study, we found that 10 2 colony-forming units of inoculum produced an optimal infection rate of 90-100%, which substantially challenged the immune system without overwhelming sepsis. We hypothesized that, in traumatic fractures, there is a specific immunological response that may lead to an increased rate of infection. In Part 2, we demonstrated immunosuppression (decreased Interleukin-12 levels) at days 6, 10, and 12 after fracture fixation versus nonfractured control groups (p < 0.05). This study describes a rat model of femur factures with osteomyelitis that allows investigation of posttraumatic immunosuppression. ß

The purpose of this study was to evaluate the failure rate of proximal femoral locking plates after an initial 2 years of use at a Level I trauma center. This retrospective chart review included 13 patients with intertrochanteric or peritrochanteric femoral fractures who underwent open reduction and internal fixation. Average patient age was 47 years (range, 23-80 years); average follow-up was 12.7 months (range, 2 weeks to 23 months). Three (23%) patients experienced catastrophic failure of the implant. The overall revision rate was 46% (6 of 13). One patient experienced avascular necrosis and required a planned total hip arthroplasty. In the appropriate setting, the proximal femoral locking plate can offer stable fixation for fractures involving the proximal femur; however, this series highlights the difficulties associated with treating these injuries, especially in patients with multiple injuries. Care must be taken to avoid varus malalignment and to address metabolic bone dysfunction.