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).

Quantitative Assessment of Tendon Healing by Using MR T2 Mapping in a Rabbit Achilles Tendon Transection Model Treated with Platelet-rich Plasma.

PURPOSE: To determine if magnetic resonance (MR) imaging T2 mapping can be used to quantify histologic tendon healing by using a rabbit Achilles tendon transection model treated with platelet-rich plasma (PRP). MATERIALS AND METHODS: Experiments were approved by the Institutional Animal Care and Use Committee. The Achilles tendons of 24 New Zealand white rabbits (48 limbs) were surgically transected, and PRP (in the test group) or saline (in the control group) was injected into the transection site. The rabbits were sacrificed 2, 4, 8, and 12 weeks after surgery. Thereafter, T2 mapping and histologic evaluations were performed by using the Bonar scale. A mixed-model multivariate analysis of variance was used to test the effects of time and PRP treatment on the T2 value and Bonar grade, respectively. The correlation between the T2 value and Bonar grade was also assessed by using the Spearman correlation coefficient. RESULTS: The Bonar scale values decreased in both groups during tendon healing. The T2 value also shortened over time (P < .001 for both groups). The T2 values were positively correlated with the Bonar grade (ρ = 0.78, P < .001). Both the T2 value and Bonar scale value were lower in the PRP group than in the control group at 4, 8, and 12 weeks; however, there was no significant effect of PRP treatment on the T2 value or Bonar grade. CONCLUSION: The T2 value changes reflected histologic tendon healing. While T2 and Bonar grade were lower at all time points in tendons treated with PRP, there was no significant difference between the treatment and control tendons.

Spontaneous repair of partial thickness linear cartilage injuries in immature rats.

Partial thickness articular cartilage injuries (PTCIs) were not previously thought to heal spontaneously. Immature rats have the capacity for spontaneous repair of PTCIs, although it is a long-term process. Our aim has been to examine the spontaneous repair response mechanism in immature rats. Single linear PTCIs were created in 3-week-old and 12-week-old rats in the direction of joint motion. On day 1 and at 1, 2, and 4 weeks after PTCI, evaluations of histological changes and immunohistology at the injury site and in the surrounding cartilage were performed. Anti-CD105 and anti-CD166 antibodies (as stem cell markers to identify mesenchymal stem cells in reparative cartilage tissue) were used for immunohistological evaluations. To determine whether endogenous repair ability existed in articular cartilage, an ex vivo experiment was also carried out. Femoral condyles with PTCIs were incubated in Dulbecco's modified Eagle's medium containing 10% fetal bovine serum for 1 day and for 1 and 2 weeks. Histological changes were subsequently examined. Immature cartilage showed a higher repair response than did mature cartilage, and the response occurred immediately after PTCI. In immature rats, CD105- and CD166-positive cells were found in the superficial and transitional zones of the articular cartilage. Few CD166-positive cells were identified in mature articular cartilage. No significant in vivo differences in the spontaneous repair responses to PTCIs were observed between mature and immature groups. Thus, the repair response to PTCIs seems to be associated not only with CD105- and CD166-positive cells, but also with other perichondral factors.

Radiation Exposure During Lumbar Interbody Fusion Surgery Can Be Reduced by Using a Three-Dimensional Patient-Specific Template Guide.

BACKGROUND: The use of posterior lumber interbody fusion (PLIF) using cortical bone trajectory (CBT) with a patient-specific 3D template guide is increasingly widespread. To our knowledge, no studies have extensively evaluated the reduction of radiation exposure when using patient-specific drill template guides. The purpose of this study is to compare the intra-operative radiation dose and surgeon's exposure to radiation in CBT-PLIF when using a patient-specific drill guide with that in traditional minimally invasive (MIS)-PLIF. METHODS: In this observational study, we retrospectively compared data from five patients who were treated with single-level CBT-PLIF using a patient-specific drill guide (G group) and five patients who were treated with single-level traditional MIS-PLIF (M group). We compared the surgical time, surgeon's exposure to radiation, and intra-operative radiation time and dose between the two groups of patients. RESULTS: The mean age of the patients was 67.0 years in the M group and 74.2 years in the G group. The average surgical time was 242.8 min in the M group and 189.6 min in the G group (p = 0.020). The surgeon's exposure to radiation was 373.7 µSv in the M group and 81.75 µSv in the G group at chest level outside the protector (p = 0.00092); 42.0 µSv (M group) and 3.6 µSv (G group) at chest level inside the protector (p = 0.0000062); and 4.33 µSv (M group) and 1.20 µSv (G group) at the buttocks of the surgeon (p = 0.0013). Radiation time was 269.8 s (M group) and 56.6 s (G group) (p = 0.0097), and radiation dose was 153.7 mGy (M group) and 30.42 mGy (G group) (p = 0.00057). CONCLUSION: The patient-specific drill template guide is an invaluable tool that facilitates the safe insertion of CBT screws with a low radiation dose from the outset.

Penetrating Endplate Screw Fixation for Thoracolumbar Pathological Fracture of Diffuse Idiopathic Skeletal Hyperostosis.

With the advancement of cancer treatment and minimally invasive surgery, the indications for surgery for metastatic spinal tumors are expanding. Diffuse idiopathic skeletal hyperostosis (DISH) is a noninflammatory skeletal disease characterized by calcification and ossification of ligaments and entheses. In Japan, the prevalence of DISH is increasing with its superaging society. The purpose of this article is to report a case of applying a novel screw technique for pathological fracture in a patient with DISH and spinal metastasis. An 80-year-old man with spinal metastasis presented with acute onset of severe back pain, and investigations revealed a fracture of a metastatic lesion in T10-T12 in the range of DISH. We performed posterior fixation with a percutaneous pedicle screw system using a penetrating endplate technique. The patient's back pain improved, and he was able to mobilize with minimal assistance and survived for 8 months with a good quality of life. Spinal fracture accompanied by DISH sometimes occurs with severe instability because of injury across 3-column injury and its long lever arm. Spinal instability neoplastic score indicates instability of pathological fractures of spinal metastases but needs to be evaluated carefully when DISH is present. The prevalence of DISH is increasing in the elderly, and penetrating endplate screws can be an effective option in posterior fusion surgery for patients with DISH and spinal metastases.

Novel within ring fixation using iliac screws and an iliosacral screw locking system technique for fragility fracture of the pelvis.

Background: Surgical indications for fragility fracture of the pelvis (FFP) have been reconsidered recently, and the indications to perform surgery have increased. However, the optimal surgical method to obtain sufficiently strong fixation in elderly patients with minimal invasiveness is not yet clear. In this report, we present the case of a patient with FFP who was treated with a novel posterior within ring fixation technique using a combination of iliac screws and an implant that locks the original iliosacral (IS) screw in the sacrum. Case Description: A 90-year-old man was diagnosed with FFP (Rommens classification: Type IIc) and hospitalized for conservative treatment. However, 6 weeks after the injury, pain reappeared in his right buttock and computed tomography showed additional fractures of the right subpubic branch and right sacrum (Rommens classification: Type IVb). The fracture was considered to have progressed from being stable to unstable, and surgical treatment was planned. To obtain strong fixation with minimal invasion, we performed posterior fixation using E.Spine Tanit (Euros, France) compact posterior thoracolumbar instrumentation, an implant that combines an IS screw with a sacral anchoring system. The patient started walking unaided 2 weeks after the surgery, suggesting a good outcome of this surgical approach to FFP. Conclusion: We performed posterior fixation surgery for a patient with an unstable FFP that recurred and progressed after conservative treatment. We have achieved good results using a minimally invasive, strong, and within ring fixation technique.

Open Reduction and Internal Fixation of Simultaneous, Bilateral, Atypical Femoral Shaft Fractures After Nine Years of Bisphosphonate Treatment.

Bisphosphonates are generally used to treat osteoporosis and decrease the risk of femoral neck and vertebral fractures in patients with osteoporosis. Recently, it has been suggested that long-term bisphosphonate use can lead to decreased bone remodeling and an increased risk of atypical fractures. Atypical fractures often occur in the femur. The purpose of the present report is to describe a rare case of simultaneous, bilateral, atypical femoral fractures. An 80-year-old female was walking when she sustained bilateral femoral fractures that were diagnosed as atypical. The patient had received bisphosphonate treatment over the prior nine years.

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.

Relationship between knee osteoarthritis and meniscal shape in observation of Japanese patients by using magnetic resonance imaging.

BACKGROUND: The aims of this study were to reveal the characteristics of the meniscal shape at each knee osteoarthritis (OA) severity level and to predict trends or patterns of the meniscal shape change as associated with knee OA progression. METHODS: Fifty-one patients diagnosed with knee OA based on X-ray and magnetic resonance (MR) images were evaluated. They were divided into three groups based on the Kellgren-Lawrence (KL) grade: normal group (KL grade of 0 or 1), mild group (KL grade of 2 or 3), and severe group (KL grade of 4). We measured the patients' meniscal size and meniscal extrusion using MR images. In addition, semiquantitative measurement was performed using MR images to determine the arthritic status of the corresponding compartment using a whole-organ magnetic resonance imaging score (WORMS). RESULTS: The longitudinal diameter and posterior wedge angle of the medial meniscus were significantly larger, and the posterior wedge width of the medial meniscus was significantly smaller in the severe group than in the normal group. The WORMS scores for cartilage and osteophytes in the medial region were significantly different among the groups. The WORMS score of each region was strongly correlated with the longitudinal diameter. The WORMS scores of the lateral region were lower than those of the medial region. CONCLUSION: Our observation of the shape change of the medial meniscus in the posterior region was roughly consistent with that in many previous studies of meniscal degeneration. On the other hand, we saw that the most relevant relation between the progression of the knee OA and the deformation of the meniscus was in the longitudinal direction.

Accuracy of high-resolution ultrasound in the detection of meniscal tears and determination of the visible area of menisci.

BACKGROUND: Imaging is of great importance in diagnosing meniscal tears. The aim of this study was to assess the accuracy of high-resolution ultrasound in the diagnosis of meniscal tears, with arthroscopic examination as the standard reference, after resolution was confirmed with a target-mounted reference phantom. An additional goal was to elucidate the area of the meniscus that could be visualized with the same ultrasound machine after placement of markers into the menisci of cadaveric knees. METHODS: Seventy patients were included for the assessment of the accuracy of a high-resolution ultrasound machine with a 14.0 to 6.0-MHz linear transducer. The preoperative ultrasound diagnosis, in terms of the presence and type of tear, was compared with that in the surgical reports. In the cadaveric studies, nine needles were placed in the peripheral zone of the menisci at regular intervals and the number of needles that could be observed with the system was recorded. RESULTS: The overall sensitivity, specificity, positive predictive value, and negative predictive value of ultrasound examination for meniscal tears were 88%, 85%, 85%, and 88%, respectively. These statistical parameters did not differ significantly between the medial and lateral menisci. The sensitivity for diagnosing horizontal, vertical, radial, flap, bucket-handle, and complex tears and for detecting discoid lateral menisci was 83%, 64%, 0%, 64%, 54%, 90%, and 80%, respectively. Ten percent of the lateral menisci could not be evaluated because of poor images. The cadaveric studies revealed that the ultrasound visualized the entire meniscus except for the anterior horn. CONCLUSIONS: The findings of this study suggest that ultrasound examination may be suitable for screening for meniscal tears. The fact that almost 10% of the lateral menisci could not be evaluated because of poor images appears to be a weakness of ultrasound.

Effective knock down of matrix metalloproteinase-13 by an intra-articular injection of small interfering RNA (siRNA) in a murine surgically-induced osteoarthritis model.

This study investigated the effect of MMP-13 gene knock down on cartilage degradation by injecting small interfering RNA (siRNA) into knee joints in a mouse model of osteoarthritis (OA). OA was induced in male C57BL/6 mice by destabilization of medial meniscus (DMM) surgery. Change of Mmp13 expression over time was determined by qPCR analysis from 3 days to 6 weeks after surgery. Mmp13 and control chemically modified siRNA were injected into the knee joint 1 week after surgery and expression levels were assessed in synovium by qPCR 48 h later. Cartilage degradation was histologically assessed 8 weeks after DMM surgery according to OARSI recommendations. Mmp13 expression levels were elevated 1 week after surgery and peaked at 77 fold at 2 weeks compared to expression at 3 days. A 55% decrease of Mmp13 levels in cartilage was observed 48 h after injection of Mmp13 siRNA (p = 0.05). Significant reduction in the histological score at 8 weeks after surgery was observed in the Mmp13 siRNA-treated group compared to the control siRNA group (p < 0.001). Intra-articular injection of Mmp13 siRNA at the early phase of OA development resulted in effective knock down of Mmp13 expression and delay in cartilage degradation in vivo.