A reduced linezolid dosage maintains favorable efficacy with minimal hematologic toxicity in a methicillin-resistant Staphylococcus aureus-infected patient with renal insufficiency.

The optimal dosage of linezolid to avoid hematologic toxicity is unknown. We report the case of an 87-y-old woman with renal insufficiency who developed a surgical site infection with refractory methicillin-resistant Staphylococcus aureus. The standard dosage of linezolid (1200 mg daily) was not initially tolerated by the patient due to severe thrombocytopenia, but she was successfully treated when the dose was reduced by half (600 mg daily) based on a population pharmacokinetic-pharmacodynamic model. Appropriate dose adjustments can be made to optimize linezolid therapy especially in cases with preexisting renal dysfunction.

Clinical results of trochanteric fractures treated with the TARGON® proximal femur intramedullary nailing fixation system.

The aim of this study was to investigate the outcome of 352 (71 males) patients with trochanteric fractures that were treated with the TARGON® PF nail. The mean age was 83 years. According to the Jensen classification, there were 35 cases in type 1,94 cases in type 2,75 in type 3,63 in type 4 and 85 in type 5. Postoperative all patients were allowed to fully weight bear from the first postoperative day. Clinical and radiological data were collected at regular time intervals. The average waiting time to surgical reconstruction for the 352 cases was 3.5 days (1-7). The mean length of hospital stay was 14 days (5-22). The operative times ranged from 11 to 125 minutes with an average time of 32 minutes. Fifty percent of the patients regained their mobility to their pre-injury level at the final follow up. Out of 310 patients (88%) who were available for radiographie assessment, all fractures united except one case. 300 (85%) of the lag screws were placed in the inferior area in the anteroposterior view and in the central area in the lateral view (IM), which is regarded as the optimal position. The lag screws back-slided between 0 and 19 mms with an average of 6 mm. Sliding distance of the lag screw for over 10 mm was seen in 42 cases (13%). Varus collapse of the femoral head-and-neck greater than 10° was observed in 6 cases. Postoperative complications developed in 6 cases (1.7%), including wound infection in two cases, and secondary fracture at the subtrochanteric region, nonunion, back-out of the guiding sleeve and medial perforation of the lag screw, each in one case. The presented case series indicates that the TARGON® PF system is an effective and safe internal fixation device for trochanteric proximal femoral fractures. Further, prospective comparative evidence regarding the use of this system is needed to analyse and validate the presented clinical impression of our centre.

Prediction of postoperative ambulatory status 1 year after hip fracture surgery.

UNLABELLED: Hirose J, Ide J, Yakushiji T, Abe Y, Nishida K, Maeda S, Anraku Y, Usuku K, Mizuta H. Prediction of postoperative ambulatory status 1 year after hip fracture surgery. OBJECTIVES: To assess the validity of Estimation of Physiologic Ability and Surgical Stress (E-PASS) for predicting the postoperative risk and ambulatory status long-term follow-up after hip fracture surgery and to establish an algorithm for predicting their ambulatory status. DESIGN: Cohort study. SETTING: Twelve hospitals belonging to the regional network for hip fracture in Japan. PARTICIPANTS: The study population was composed of 421 patients; 268 underwent surgery between April 2004 and March 2006 (group A), and 153 were treated surgically between April 2006 and March 2007 (group B). All were operated at 3 surgical hospitals and, subsequently, transferred to 9 rehabilitation centers. INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: We evaluated various factors, including their E-PASS scores to determine whether there was a correlation with the patients' mortality rate and their ability to walk at discharge and 1 year after surgery (group A). Using multiple regression analysis, we then developed algorithms to predict the ability of elderly patients to walk after hip fracture surgery. We applied the algorithms to group B patients and compared their actual and predicted ambulatory status. RESULTS: In group A patients, the postoperative walking ability and mortality rate were highly correlated with their E-PASS scores and dementia status. In group B, our algorithms exhibited good correlations between the predicted and actual walking ability at both time points (rho=0.6, P<.001). CONCLUSIONS: In candidates for hip fracture surgery, the E-PASS scores exhibited a good correlation with the patients' functional and survival prognoses, and the algorithm including E-PASS scores and dementia status can accurately estimate the ambulatory status at discharge and 1 year after surgery.

Analyses of early events during chondrogenic repair in rat full-thickness articular cartilage defects.

In this study we investigated the cellular events that occur during the onset of chondrogenic differentiation during the repair of full-thickness defects of articular cartilage. The V-shaped full-thickness cartilage defects (width 0.7 or 1.5 mm; depth 0.8 mm; length 4 mm) were created in the femoral patellar groove of rats using a custom-built twin-blade device. The time course of the repair response in these cartilage defects was examined using a semi-quantitative histological grading scale. Cartilaginous repair responses failed to occur in the larger 1.5 mm defects, which was covered only by fibrous scar tissue. In contrast, hyaline-like articular cartilage was regenerated concomitantly with the repair of the subchondral bone by 4 weeks in smaller 0.7 mm width defects. Cells in the reparative regions were then characterized by immunohistochemistry and in situ hybridization. Undifferentiated mesenchymal cells migrate into the defects and fill the cavities within 4 days of their creation. The expression of PCNA, N-cadherin, and PTH/PTHrP receptors was induced in cells at the center of the defects, where type II collagen-positive polygonal-shaped cells also begin to appear at day 7. Marrow-derived mesenchymal cells acquire higher levels of proliferative activity in induced cartilage cavities after their initial migration and filling of the smaller 0.7 mm defects. During the regenerative repair of articular cartilage in the rat, there is a distinctive step that appears to be analogous to the precartilaginous condensation that is pivotal during chondrogenesis in development.