Effective screening methods to prevent surgical site infections in orthopedic surgery: an observational study.

BACKGROUND: The bacterial source of surgical-site infections (SSIs) can have either endogenous and/or exogenous origins, and some studies have revealed that endogenous transmission is an important pathway for SSIs in orthopedic surgery. However, since the frequency of SSIs is low (0.5-4.7%), screening all surgery patients is labor-intensive and cost-prohibitive. The goal of this study was to better understand how to improve the efficacy of nasal culture screening in preventing SSIs. METHODS: Nasal cultures for 1616 operative patients over a 3-year period were evaluated for the presence of nasal bacterial microbiota and the species identity. We also investigated the medical factors that influence colonization and evaluated the ratio of agreement between nasal cultures and SSI-causing bacteria. RESULTS: In a survey of 1616 surgical cases, 1395 (86%) were normal microbiota (NM), 190 (12%) were MSSA carriers, and 31 (2%) were MRSA carriers. The risk factors for MRSA carriers were significantly higher than the NM group in patients with a history of hospitalization (13 [41.9%], p = 0.015), patients who had been admitted to a nursing facility (4 [12.9%], p = 0.005), and patients who were > 75 years of age (19 [61.3%], p = 0.021). The incidence of SSIs was significantly higher in the MSSA group (17/190 [8.4%]) than the NM group (10/1395 [0.7%], p = 0.00). The incidence of SSIs in the MRSA group (1/31 [3.2%]) tended to be higher than that in the NM group, but there was no statistically significant difference (p = 0.114). The concordance rate between causative bacteria of SSI and species present in nasal cultures was 53% (13/25 cases). CONCLUSIONS: The results of our study suggest screening patients with a history of past hospitalization, a history of admission in a long-term care facility, and older than 75 to reduce SSIs. TRIAL REGISTRATION: This study was approved by the institutional review board of the authors' affiliated institutions (the ethics committee of Sanmu Medical Center, 2016-02).

Lateral Bowing of Femur Associated With Older Age, Shorter Stature, and Lower Bone Mineral Density.

We often encounter elderly patients with femur bowing. According to literature, femoral bowing is correlated with patient characteristics such as aging, race, atypical femoral fracture (AFF), and osteoporosis. However, the clear relationships between these factors and femoral bowing are still unknown. In addition, most previous reports have been based only on X-rays and may not provide accurate information due to femur rotation and inter-operator reliability when compared to the information obtained using computed tomography (CT) scans. The purpose of this study was to examine the factors associated with anterior and lateral bowing in detail, by using three-dimensional preoperative measurement software Zed Hip®ï¸Ž (LEXI Co. Ltd., Tokyo, Japan). A total of 364 patients with trochanteric hip or femoral neck fractures, or osteoarthritis, treated in our hospital were included in this study. Of these, 61 patients older than 50 years, who had complete CT volume data for the entire length of the femur on the healthy side and bone mineral density (BMD) measured by trunk dual-energy X-ray absorptiometry (DXA), were investigated. There were 13 males and 48 females, aged 53-97 years (mean 78.7±10.8 years). We defined the starting and ending points of the femoral diaphysis to measure anterior bowing (AB) and lateral bowing (LB) of the femoral diaphysis. The correlation between AB or LB with each patient's characteristics (age, height, weight, lumbar BMD, and femoral BMD) was examined retrospectively. AB did not correlate with any of the patient parameters. LB weakly positively correlated with age and was negatively correlated with height and femoral (greater trochanter) bone density. Weight was in no correlation with either AB or LB. A novel three-dimensional approach was used for measurements that may be more accurate than plain two-dimensional radiographs.

Cytokine/chemokine elevation during the transition phase from HSV encephalitis to autoimmune anti-NMDA receptor encephalitis.

A 3-year-old girl suffered from anti-N-methyl-d-aspartate (anti-NMDA) receptor encephalitis after resolution of herpes simplex virus encephalitis (HSE). Methylprednisolone pulse and immunoglobulin therapies showed little effect, but the patient completely recovered after six courses of monthly cyclophosphamide pulse therapy and successive maintenance on mycophenolate mofetil for one year. Anti-NMDA receptor antibody in the cerebrospinal fluid (CSF) was minimally detected during the prodromal febrile period and then was seen to be markedly elevated at the onset of second encephalopathy phase. CSF interleukin (IL)-6, and 10, tumor necrosis factor-α, interferon gamma, C-X-C motif ligands (CXCL)10 and 13, chemokine ligand 2, and migration inhibitory factor showed a second peak during the prodromal period and were reduced at the onset of anti-NMDA receptor encephalitis. These suggest the presence of cytokine/chemokine phase between the initial HSE and the secondary autoimmune encephalitis phases. Treatment strategy during the early stage of this entity should be further explored.

Pain-related behavior and the characteristics of dorsal-root ganglia in a rat model of hip osteoarthritis induced by mono-iodoacetate.

The principal aim of this study was to clarify the time course of pain-related behavior and pain-related sensory innervation in a rat model of hip osteoarthritis (OA) induced by intra-articular injection of mono-iodoacetate (MIA). Using 6-week-old male Sprague Dawley rats, 25 µl of sterile saline of 1% Fluoro-Gold solution (FG) (control group; n = 30) and 25 µl of sterile saline of 1% FG with 2 mg of MIA (MIA group; n = 30) was injected into the right hip joints. Gait function was evaluated using a CatWalk system after 7, 14, 28, 42, and 56 days (n = 5, respectively). Neurons in the dorsal root ganglion (DRG) between L1 and L5 were immunostained for calcitonin gene-related peptide (CGRP) and activating transcription factor-3 (ATF3). Gait analysis revealed the mean six parameters of hind paws at all time points were significantly lower in the MIA group (p = 0.05). The number of CGRP-immunoreactive (-IR) DRG neurons was significantly increased on days 7, 14, 28, and 42 peaking at 14 days in the MIA group. By contrast, expression of ATF3-IR in FG-labeled DRG neurons was significantly increased on days 42 and 57. The FG-labeled DRG neurons were distributed between L1 and L5, mainly at the L4 level. Pain-related behavior indicated by gait disturbance was observed in a MIA model of hip OA in rat. Early elevation of CGRP expression and late expression of ATF-3 were demonstrated in DRG neurons, possibly reflecting inflammatory pain and neuropathic pain in hip OA. © 2017 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 35:1424-1430, 2017.

Bilateral Necrotizing Fasciitis of the Foot Associated with Group B Streptococcus.

Necrotizing fasciitis (NF) is a severe bacterial infection involving fascia and subcutaneous tissue. It generally affects upper or lower extremities unilaterally, and there are few reports of bilateral-extremity NF. Here, we report a case of a 43-year-old male with type 1 diabetes who had NF on the left foot and subsequently developed NF on the other foot 1 week later. The patient survived with antimicrobial therapy and bilateral below-knee amputation. As group B streptococcus (GBS) was isolated by blood culture and culture of excised tissues of both feet, bilateral GBS NF of the foot was diagnosed. GBS is a rare causative pathogen in NF; however, there have been two case reports of bilateral GBS NF of an extremity in which NF appeared on the opposite extremity 1 week after the primary site infection, as in our case. GBS was isolated from cultures of blood and excised tissues of both extremities in both cases. Together, these observations suggest that GBS has a potential to cause secondary NF at remote sites by hematogenous dissemination with approximately 1 week delay and thereby lead to bilateral NF.

Intra-articular injection of mono-iodoacetate induces osteoarthritis of the hip in rats.

BACKGROUND: The mechanism for hip pain has been unclear because of a lack of experimental animal models. We aimed to establish an intra-articular injection technique to the rat hip and to document the effect of intra-articular mono-iodoacetate (MIA) injection to the rat hip with radiography and histology. METHODS: Using 60 6-week-old male Sprague Dawley rats, 25 µl of sterile saline (control group; n = 30) and 25 µl of sterile saline with 2 mg of MIA (MIA group; n = 30) was injected into the right hip joints via posterior approach using a 27G needle. The animals were examined with X-ray and histology 7, 14, 28, 42, and 56 days later (MIA group [n = 6] and control group [n = 6], respectively). RESULTS: The MIA group showed progressive radiographic changes to the hip joint during the experimental period, whereas the control group maintained a normal appearance. The microanatomic appearance was consistent with X-ray images of progressive destruction in the MIA group and normal tissue in the control group. Osteoarthritic (OA) changes became apparent at 42 and 56 days in the MIA group. CONCLUSIONS: We established an intra-articular injection technique to the rat hip, creating a hip OA model in the rat by intra-articular injection of MIA.

Corticosteroids and low bone mineral density affect hip cartilage in systemic lupus erythematosus patients: Quantitative T2 mapping.

BACKGROUND: The purpose of this diagnostic study was to quantify the effect of high-dose corticosteroid treatment on hip joint cartilage degeneration in patients with systemic lupus erythematosus (SLE), with and without osteonecrosis, using magnetic resonance imaging (MRI). METHODS: T2 mapping, with a 3.0 Tesla Discovery MR750 (GE Healthcare) MRI scanner, was performed in 12 volunteers without hip pathology (control group, 12 hips), in 11 patients with SLE without osteonecrosis, who were receiving corticosteroid therapy (corticosteroid-ON group, 17 hips), and in 15 patients with SLE receiving corticosteroids, who had noncollapsed and asymptomatic osteonecrosis (corticosteroid+ON group, 26 hips). The distribution of T2 values in the femoral head and acetabular cartilage were compared among the three groups. Step-wise multiple regression analysis was performed to determine the prognostic factors for T2 values indicative of femoral head cartilage degeneration. RESULTS: Mean T2 values of femoral head cartilage were significantly higher in the corticosteroid-ON (40.3 ms) and corticosteroid+ON (35.2 ms) groups than in the control group (30.1 ms, P = 0.001). T2 values of acetabular cartilage were significantly higher in the corticosteroid-ON group (41.8 ms) versus the control (33.4 ms) and the corticosteroid+ON groups (37.0 ms; P = 0.001). Low bone mineral density was a significant prognostic factor for high T2 values of cartilage at the femoral head in patients treated with corticosteroids, regardless of whether they had osteonecrosis. CONCLUSION: T2 mapping suggests that corticosteroid therapy and osteoporosis are independent risk factors for cartilage degeneration at the femoral head in patients with SLE.

A novel rat model of hip pain by intra-articular injection of nerve growth factor-characteristics of sensory innervation and inflammatory arthritis.

OBJECTIVES: To determine the direct effects of intra-articular injection of nerve growth factor (NGF) into normal rat hips and the time course of pain-related mediator appearance. METHODS: Using 36 numbers of 8-week-old male Sprague-Dawley rats, 30 µl of 1% Fluoro-Gold solution (FG) (Sham-operated group; n = 12), 30 µl of 1% FG with 50 µg/ml NGF (NGF50 group; n = 12), and 30 µl of 1% FG with 100 µg/ml NGF (NGF100 group; n = 12) were injected into the left hip joints. Neurons in the dorsal root ganglion (DRG) labeled with FG, and FG and calcitonin gene-related peptide-immunoreactivity (CGRP-IR) were counted. The synovia in the left hip joint was examined histologically. RESULTS: The NGF50 and NGF100 groups showed evidence of synovitis without cartilage degeneration compared with the Sham-operated group. At 7 days, the proportions of CGRP-IR FG-labeled to total FG-labeled neurons were 12%, 18%, and 36% in the Sham-operated, NGF50, and NGF100 groups, respectively. At 14 days, the proportions were 13%, 22%, and 35% in the Sham-operated, NGF50, and NGF100 groups, respectively. At 7 and 14 days, the NGF50 and NGF100 groups showed a significantly higher proportion of CGRP-IR FG-labeled neurons than the Sham-operated group. CONCLUSIONS: Intra-articular administration of NGF into the hip joint produces a novel rat model for hip pain.

Transient up-regulation of P-glycoprotein reduces tacrolimus absorption after ischemia-reperfusion injury in rat ileum.

Ischemia-reperfusion injury is an unavoidable problem for organ transplantation including small bowel transplantation, and causes a large intra-individual variation of tacrolimus (FK506) pharmacokinetics. Little information is available about the regulation of the intestinal P-glycoprotein expression during tissue regeneration. In the present study, we have examined the molecular and functional variations of ileum P-glycoprotein using rats after ischemia-reperfusion treatment. Morphological study revealed a rapid regeneration of the intestinal wall during 24 h after reperfusion. A reverse transcription-coupled competitive PCR and Western blot analysis revealed that the intestinal expression of P-glycoprotein recovered with time after reperfusion. At 24 h after reperfusion, the ileum P-glycoprotein level was transiently increased to two-fold, and the absorption rate of dihydro-[(3)H]FK506 from in situ ileum loop into portal vein was markedly low in comparison with the control. P-glycoprotein was detected in the crypt area as well as in villous cells at 6 h after reperfusion, and then localized to the apical surface at 24 h consistent with the cell proliferation and differentiation. However, the P-glycoprotein level returned to normal at 48 h. The intra-individual variation in the absorptive rate of tacrolimus was suggested to be regulated by the morphological status of the intestinal epithelium and enterocyte expression level of P-glycoprotein. Therefore, the monitoring of the enterocyte P-glycoprotein level would provide useful information for determining the dosage of tacrolimus immediately after small bowl transplantation.