Duration of extremity tourniquet application profoundly impacts soft-tissue antibiotic exposure in a rat model of ischemia-reperfusion injury

IntroductionExtremity tourniquet (TNK) application is an effective means of achieving compressible hemorrhage control in the emergency prehospital and clinical trauma setting. Modern United States military medical doctrine recommends TNK use to prevent lethal hemorrhage from extremity injury, followed by systemic prophylactic antibiotics to prevent wound infection. Because tissue pharmacokinetics of prophylactic antimicrobials during and after TNK-induced limb ischemia are largely unknown, this study was conducted to empirically determine the relationship between TNK application time and soft tissue antibiotic exposure in order to guide medical personnel in the management of extremity trauma.Materials and MethodsHind limbs of anesthetized male Sprague Dawley rats were exsanguinated, and ischemia maintained by a pneumatic cuff placed at the level of the mid femur on one limb; the non-ischemic contralateral limb served as comparison tissue. Systemic prophylactic antibiotics (cefazolin, moxifloxacin, or ertapenem) were administered intravenously before or after TNK release following 2 or 4 h of ischemia with subsequent re-dosing every 12 h for 3 days. Free antibiotic in the interstitial fluid (ISF) of the tibialis anterior muscle of both hind limbs was recovered via microdialysis during ischemia and over three periods during reperfusion: immediately following TNK release, at 24 h post TNK release, and at 72 h post TNK release. Plasma and ISF free drug concentrations were determined by high-performance liquid chromatography.ResultsTourniquet application prevented delivery of prophylactic antibiotics into distal soft tissue for the duration of ischemia, and caused a profound reduction in skeletal muscle drug exposure for up to 72 h following TNK release. A progressive decline in tissue antibiotic exposure during reperfusion was observed as TNK times increased from 2 h to 4 h. The timing and severity of reduced drug distribution in post-ischemic skeletal muscle varied substantially among the three antibiotic classes evaluated.ConclusionsProlonged tourniquet application can significantly reduce distribution of prophylactic antibiotics into soft tissue during and after ischemia, potentially impairing prophylaxis of extremity wound infection. Our findings support the examination of alternative approaches to wound infection prophylaxis under conditions of delayed casualty evacuation when occlusive hemorrhage control measures are utilized.     

Editorial Commentary: Arthroscopy of the Hip (Not the Abdomen!)

Hip arthroscopists and the surgical team should be aware of the potential complication of intra-abdominal fluid extravasation (IAFE). Fluid extravasation may be relatively common. Fortunately, symptomatic IAFE remains rare but can be serious. Increased peak inspiratory pressure (PIP) should be a parameter that we follow and discuss with our anesthesia colleagues. This would be an excellent point to bring up during the mandatory preoperative time out. Increased PIP or hemodynamic instability should warrant a consideration of IAFE.     

The Influence of Iodine-Impregnated Incision Drapes on the Bacterial Contamination of Scalpel Blades in Joint Arthroplasty

BackgroundProsthetic joint infections (PJI) are a disastrous and feared complication in arthroplasty. Over the past decades, surgeons have tried to lower infection rates through all sorts of improvements. At present, it is impossible to reduce the risk to zero. As the contamination of surgical instruments and the surgical field has been identified as a remaining gap prone for infection, scalpel blades among others have become a focal point of several studies. This study is the first to compare the effect of adhesive incision drapes on contamination rates of scalpel blades in primary arthroplasty of the hip and knee.MethodsA total of 344 microbiologic blade culture results from 2 study groups with and without drape usage and 1 group with known PJI were analyzed and compared to histopathologic and microbiologic tissue results.ResultsIn 78% of all positive cultures, the bacteria were part of the local skin flora. The contamination rate for the skin blades with a drape was 3.81% vs 12.19% without drape usage. A significant difference was determined between positive skin blade culture results incision drape usage (P = .031). The different pathogens likely responsible for the PJI correlated with the deep blade cultures (P ≤ .01). The overall contamination rate of surgical blades (1.37%) is comparatively low to the results obtained from other surgical equipment in literature. None of those blade-positive patients developed a surgical site infection during 12-month follow-up.ConclusionIodine-impregnated incision drapes are able to reduce surgical skin blade contamination. Further studies may be needed to assess the relationship between blade contamination and surgical site infections.     

Editorial Commentary: Meniscal Allografts Can Be for Grandparents Too

Meniscal allografts have come a long way since they were first thought to be a salvage procedure before a knee arthroplasty. The surgical procedure and indications have shown significant change, but the variable of patient age has not. Most clinical series report that patients should be <50-55 years of age to be considered as candidates. While outcomes are better for younger patients, good results can be obtained even when the upper age is extended beyond the current accepted limit.     

Risk analysis of tunnel collision in combined anterior cruciate ligament and anterolateral ligament reconstructions

BackgroundTo assess the risk of tunnel collision in combined anterior cruciate ligament (ACL) and anterolateral ligament (ALL) reconstructions.MethodsThree-dimensional (3D) CT reconstructions of 32 knees after transtibial (TT) (N = 16) or anteromedial portal (AMP) (N = 16) ACL reconstruction were used to simulate potential tunnel collision of the femoral ACL tunnel if combined with a virtual ALL reconstruction. The minimal distance between tunnels, the ALL tunnel length, and the lateral femoral condyle (LFC) width were measured. Moreover, the relationship between the ALL tunnel and the intercondylar notch, trochlear groove and posterior femoral cortex was determined.ResultsThe highest rate of tunnel collision (81%) was observed when the ALL tunnel was aimed at 20° in the coronal plane and 0° in the axial plane. However, by aiming the ALL tunnel at 0° coronal and 40° axial angulation, collision was avoided in all patients and no violation of the trochlea was observed. Tunnel collision rate was significantly higher (P = 0.002) when the ACL tunnel was drilled by the AMP technique.ConclusionsRisk of tunnel collision was significantly increased when the tunnel was drilled at 0° in the axial plane. Tunnel collision was avoided by aiming the ALL tunnel 40° anteriorly and perpendicular to the anatomical axis of the femur. A more horizontal orientation of the ACL with the AMP technique is a risk factor for tunnel conflicts.Clinical relevanceALL tunnel orientation needs to be adjusted to avoid tunnel conflicts in combined ACL–ALL reconstructions.