Dual Antibiotic Prophylaxis in Primary Total Knee Arthroplasty-No Benefit for Extremely Obese Patients.

We performed this study to assess the effectiveness of multimodal total knee arthroplasty prosthetic joint infection (TKA-PJI) prophylaxis including "on-time" dual-antibiotic prophylaxis, and the influence of body mass index (BMI) on prophylaxis effectiveness. After obtaining Institutional Review Board approval, we assessed 1,802 primary TKAs (1,496 patients) who received cefazolin alone or cefazolin combined with vancomycin for TKA-PJI prophylaxis. A detailed chart review was performed to determine patient demographic features (age, gender, BMI, American Society of Anesthesiologists Score), antibiotic selection, vancomycin administration timing, and 1-year PJI rates. Statistical assessment was accomplished using a two-sided Student's t-test or Fisher's exact test. Patients who received dual-antibiotic prophylaxis with "on time" vancomycin infusion (Group CVt) had significantly lower infection rates than other TKA patients (0.8 vs. 2.7%, p < 0.01). "On Time" vancomycin administration was associated with a lower TKA-PJI rate for patients with a BMI < 45 kg/m2 (0.5 vs. 2.6%, p < 0.01) with no infections in 120 TKA patients with a BMI between 40 and 44.9 kg/m2 (p < 0.01). No difference was noted for patients with a BMI ≥ 45 kg/m2 (3.3 vs. 2.6%, p = 0.71). There were no infections in 150 TKA patients with a normal BMI (18-25 kg/m2) in any PJI-prophylaxis treatment group. Adoption of a dual-antibiotic prophylaxis approach can successfully reduce TKA-PJI rates among overweight and moderately obese patients. The approach does not appear to influence outcomes for low risk patients with a normal BMI (18-25 kg/m2) or for higher risk patients with a BMI > 45 kg/m2.

Exercise-Induced Acute Bilateral Upper-Arm Compartment Syndrome.

We present a rare case of acute exercise-induced bilateral upper-arm compartment syndrome in a patient who, after a year-long hiatus from exercise, subjected his upper-extremities to the stress of over 100 pushups. The patient presented with severe pain of the bilateral biceps and triceps and complaints of dark urine. Decompressive fasciotomy was performed followed by an intensive care unit (ICU) stay for associated myoglobinuria secondary to rhabdomyolysis. The patient suffered no long-term sequelae as a result of his conditions and recovered full function of the bilateral upper-extremities. Albeit rare, acute exercise-induced compartment syndrome should be considered as a diagnosis following unaccustomed bouts of exercise.

Proximity of Lateral Critical Structures to the All-Epiphyseal Outside-In Femoral Tunnels in Pediatric Anterior Cruciate Ligament Reconstruction.

PURPOSE: To describe the proximity of the lateral critical structures (peroneal nerve [PN], popliteus tendon [PT], lateral collateral ligament [LCL], and articular cartilage [AC]) to the femoral tunnel for outside-in all-epiphyseal anterior cruciate ligament (ACL) reconstruction in reference to knee flexion angle. METHODS: All-epiphyseal ACL reconstructions were performed in 12 human cadaveric knees using arthroscopy and outside-in drilling for anatomic femoral tunnel placement that was ensured by identifying the center of the total ACL footprint. Fluoroscopy was used to confirm tunnel position and reconstructions were performed with quadrupled semitendinosus and gracilis autograft with Xtendobutton (Smith & Nephew, Andover, MA) fixation on the femoral side. After reconstruction, the lateral side of the knee was dissected and the LCL, PT, distal and posterior AC, and the PN were identified. The distances of these structures from the center of the exiting femoral tunnel were then measured using a digital caliper at 0°, 30°, 60°, 90°, and 120° of knee flexion. Any gross damage to these structures caused by the femoral drilling was also noted. Data were compiled and the mean and standard deviations (SD) of the distances from the pin to the structures of interest were calculated. The normality of the data at each flexion angle was assessed using Shapiro-Wilk tests (P > .05), and the relationship between flexion angle and average distance was evaluated using repeated measures analysis of variance (P < .05). Any significant relationships were then evaluated using paired t-tests (P < .05) with a Benjamini-Hochberg adjustment for each possible pair of flexion angles. Averages, SD, and P values are reported. A post hoc power analysis was performed. RESULTS: The violation of the LCL was noted in 3 specimens and that of the PT in 1 specimen as a result of femoral tunnel drilling at flexion angles ranging from 90° to 120°. The distance between the PT and the femoral tunnel also decreased significantly (P < .001) with knee flexion with average distances to the center of 8.07 mm at 0°, 7.75 mm at 30°, 6.33 mm at 60°, 4.12 mm at 90°, and 1.89 mm at 120°. The mean ± SD for distances from the femoral tunnel to the center of the PT at 0° was 8.07 ± 7.15, at 30° 7.75 ± 6.66, at 60° 6.33 ± 6.79, at 90° 4.12 ± 5.71, and at 120° 1.89 ± 5.56. As the knee was progressively flexed, the distance between the LCL and the femoral tunnel decreased significantly (P < .001) with an average distance of 6.52 mm at 0°, 6.26 mm at 30°, 4.23 mm at 60°, 2.38 mm at 90°, and 0.4 mm at 120°. The mean ± SD for distances from the femoral tunnel to the center of the LCL at 0° was 6.52 ± 5.93, at 30° 6.26 ± 7.32, at 60° 4.23 ± 7.82, 90° 2.38 ± 7.31, and at 120° 0.4 ± 7.01. The PN was remote from the femoral tunnel at all flexion angles with a mean distance of 42.83 to 59.22 mm. The PN to guide pin distance increased significantly with progressive knee flexion (P < .001). The AC was not damaged in all specimens. CONCLUSIONS: The LCL and PT are at significant risk during percutaneous femoral drilling for all-epiphyseal anatomic ACL reconstruction using an outside-in technique. This risk was maximized at 120° flexion and minimized in full extension. These findings suggest that the optimal position for femoral drilling in all-epiphyseal ACL reconstruction is full or near-full extension of the knee that can be accomplished by placing the knee in 30° of flexion (after using fluoroscopic guidance to pass the guide pin past the lateral critical structures) to visualize the footprint of the ACL. CLINICAL RELEVANCE: Information garnered from this study may help clinicians better understand the risk to the lateral critical structures when an outside-in femoral tunnel is not drilled in the appropriate degree of knee flexion.

Morbidity and Mortality of Bilateral Femur Fractures.

Bilateral femur fractures have been associated with frequent morbidity and mortality. Associated injuries and massive hemorrhage contributed to mortality rates that were as high as 27% in previous reports. The goals of this study were to determine the frequency of associated complications, including mortality, and to identify which patient and injury features are associated with increased morbidity and mortality. The authors proposed that some patients with bilateral femur fractures may undergo early definitive fixation with an acceptable rate of complications. Patients who had bilateral femur fractures during the same injury event were retrospectively reviewed. Demographic characteristics, associated injuries, and the type and timing of treatment were determined. Complications were identified. The authors identified 50 men and 22 women, with a mean age of 41.5 years, who had high-energy bilateral femur fractures. These patients accounted for 5.5% of all femur fractures treated at the authors' institution over a period of 11 years. Two patients died before fixation. In addition, 13 other patients (19%) had 21 complications, including pneumonia in 6 (8.6%) and deep venous thrombosis in 7 (10%). No patient had adult respiratory distress syndrome, but 2 died of multiple organ failure. All patients with pulmonary complications had an underlying chest injury (P=.004). The overall mortality rate was 6.9%, and mortality was associated with higher mean age and higher Injury Severity Score (ISS). Of the 60 patients who had definitive fixation within 24 hours of injury, 53 (88%) had no complications. Complication rates were similar to those reported in the literature, with a mortality rate of 6.9%, including 3 patients who died after femoral fixation. Mortality was associated with advanced age and higher ISS. Chest injuries were associated with pulmonary complications. Most patients had early definitive fixation without complications, but it is not possible to predict which patients may be safely treated on an early basis.