Anterior or posterior obliquity of the lag screw in the lateral view--does it affect the sliding characteristics on unstable trochanteric fractures?

We investigated the sliding pattern characteristics of proximal fragment in 16 proximal femur models of 31-A2.1 type trochanteric fractures fixed with dynamic hip screw system under load. In eight models, the lag screw was inserted with an anterior-to-posterior vector within the neck and the head of femur (group 1). The other eight had a posterior-to-anterior vector (group 2). A force of 500 N (30 cycles) was applied to the fracture fragment-plate complex using the Instron 6022. No significant difference was noted in the sliding distance between the two groups (p=0.17). However, the mean angle of rotation of the proximal fragment was twice as great in group 1 (16+/-3.7 degrees ) than that in group 2 (8.1+/-1.5 degrees ) (p<0.001). In group 1, early eccentric contact in the anterior aspect of the intertrochanteric area caused internal rotation of the proximal fragment. Breakage of the anterior cortex of the lateral wall was noted in five out of the eight cases in group 1 and no case in group 2 (p=0.026). Fracture of the anterior cortices significantly threatened the integrity of the lateral wall in group 1.     

A sliding hip screw augmented with 2 screws is biomechanically similar to an inverted triad of cannulated screws in repair of a Pauwels type-III fracture

ObjectivePauwels III femoral neck fractures are highly unstable. These fractures are commonly treated with three cannulated screws or sliding hip screw (SHS) implants, however high rates of non-union persist. A hybrid SHS construct has recently been proposed. The objective of the study was to compare this construct to the familiar inverted triad of cannulated screws and to a single SHS.MethodsFourth generation biomechanical femur analogs were used to create a highly repeatable injury model. The hybrid SHS construct contained a SHS with two superior cannulated screws in an inverted triangle configuration. Eight samples for each construct were biomechanically evaluated and the results compared using ANOVA (p < 0.05).ResultsThe cannulated triad and hybrid SHS provided similar stiffness and fracture gap motion. The single SHS exhibited significantly lower stiffness and larger fracture plane diastasis than either the inverted triangle of cannulated screws or hybrid SHS (p < 0.05). None of the constructs exhibited catastrophic failure during cyclic loading nor under loading up to 2.5 times body weight.ConclusionsThe single SHS provided the least stable fracture fixation, while the inverted triad and hybrid SHS constructs were mechanically similar. The fracture repair simulated here illustrates how these repairs have the potential to return near pre-fracture strength in ideal conditions with young, healthy bone. However; in clinical situations where comminution impairs load transfer through the cortices the hybrid SHS may be the most favorable option.     

Inguinal hernias containing the uterus: A case series of 7 female children

Background

Hernia uteri inguinale (HUI), or uterus-containing inguinal hernia, is an extremely rare condition in which the uterus and uterine adnexa are found in the inguinal hernial sac in female infants. The uterus may be free within the sac adherent to the wall by adhesions or a true sliding component. However, in true sliding-type HUI, one of the walls of the hernia sac is formed by the uterus itself.

Patients and Methods

The medical records for all female children with inguinal hernia who were operated from 1999 through 2010 were reviewed retrospectively (n = 3100).

Results

Among these patients, we identified seven cases of HUI in infants with a normal female karyotype. The incidence of HUI was 0.23%. Patients were discharged on the postoperative 1st day with no complications.

Conclusions

Surgeons should be aware of the possibility of presence of the uterus or another organ in the hernial sac in phenotypic female children, and sliding components should be replaced carefully into the abdomen to prevent any damage.     

滑行窗口技术在痛觉脑诱发电位分析中的应用

目的：评价滑行窗口技术分析脑电诱发电位的能力。方法：将具有一定宽度的时间窗口延时间轴滑行，计算该窗口内的脑电电位平均值，再与对照窗口进行统计比较，以检验诱发电位是否具有统计显著性。利用该方法分析随机产生的模拟数据，计算在指定单次检验阈值下，多次统计比较导致显著性差异点连续出现的几率，以确定可使整体α值小于0．05的cluster大小。为检验该方法的有效性，在14名健康右利手志愿者右手中指给予痛或非痛电刺激，记录EEG信号并采用上述技术加以分析。结果：在整体α值确定的前提下，作为显著性判据的cluster大小随单次检验阈值与窗宽的增加而增大。依据上述方法分析真实EEG数据，确定了体感与痛觉诱发电位波形中具有统计学意义的成分，以及两种波形之间的显著性差异。结论：滑行窗口技术可有效地用于分析脑电诱发电位。     

双层补片腹膜前修补治疗腹股沟滑疝的效果观察

目的：探讨采用善愈双层补片腹膜前修补治疗腹股沟滑疝的临床效果。方法回顾性分析2010年3月至2013年3月我院结直肠肛门外科收治的48例腹股沟滑疝患者的临床资料,根据手术方式分为传统组(22例,采用传统疝修补手术)、双层补片组(26例,采用善愈腹膜前双层补片腹膜前修补手术),比较两组患者的术中术后情况。结果双层补片组手术时间为（23.7±5.2）min、VAS评分为(0.86±32)分、术后使用镇痛剂率为11.54%、术后下床活动时间为(16.8±5.1) h、术后恢复工作时间为(35.5±8.3) d,均显著低于传统手术组(P<0.05);两组患者的住院时间、术后1年复发率比较差异均无统计学意义(P>0.05)。传统组术后共出现并发症9例(40.91%),显著高于双层补片组的2例(7.69%)(χ2=7.443,P=0.006)。结论善愈双层补片腹膜前修补治疗腹股沟滑疝较传统手术治疗具有手术时间短、恢复较快、术后并发症少等优点。     

Cellular basis for volume related wall thickness changes in the rat left ventricle

Nine arrested rat hearts fixed by glutaraldehyde perfusion of the coronary arteries were studied in vertical cross-sections of the left ventricle by phase contrast microscopy. The number of fibers per unit area in the wall and the number of fibers between the epicardium and endocardium were measured and correlated with ventricular volume and wall thickness. Average center to center fiber separation was derived from these measurements.Increasing ventricular volume is associated with a decrease in wall thickness and fiber diameter which follows theoretical predictions. The relationship between these measurements, however, presents a dimensional paradox in that the decreases in wall thickness are 3 to 4 times greater than the decrease observed in separation of fiber centers. Thus, an increase in fixation volume from 0.03 to 0.60 ml results in a 68% decrease in wall thickness, while center to center fiber separation decreases only 20%. Changes in wall thickness are therefore mainly accounted for by internal rearrangement of the disposition of fibers composing the ventricular wall. A mechanism for such rearrangements is illustrated by low magnification cross-sections of the ventricular wall which demonstrate open spaces or sliding planes between groups of muscle fibers. A volume related alteration in the orientation of these sliding planes is noted.     

Observation of retrieved ceramic-on-ceramic articular surface: a case of revised total hip arthroplasty due to failure of the support ring

We report the case of a 63-year-old woman who required revision surgery for ceramic-on-ceramic total hip arthroplasty (THA) due to failure of the support ring. We retrieved the ceramic cup and head, observed it macroscopically and measured it to determine its shape condition (sphere diameter, sphericity, and circularity) and surface condition (surface roughness by scanning electronic microscopy). Although abrasion was not found at the sliding surface of either the cup or head, it was observed at the edges of the cup and at one part of the head. We point out the risk of the edge contact and conclude the possibility of micro-motion between the cup and the head during walking or loading in vivo, and that contact had taken place at such parts.     

双槽沟托槽滑动阻力的实验研究

目的 评价模拟尖牙滑动时双槽沟托槽的滑动阻力,探讨临床应用双槽沟托槽的合适牵引力.方法 将粘有托槽的人工尖牙置于硅胶槽内,分别在10g、15g和20g力牵引下沿弓丝滑动.双槽沟托槽组中人工尖牙在双圆丝(直径0.016英寸和0.018英寸)支撑下移动.对照组为常规方丝托槽和方丝(0.016英寸×0.022英寸)组合.通过激光测距仪及相连计算机得到的牙齿移动速率,分析牙齿滑动时所受阻力的大小.结果 牵引力为10g力和15g力时,双槽沟托槽组平均移动速率较小.当牵引力增加到20g力,双槽沟托槽组平均速率大于常规托槽组.结论 在足够牵引力的作用下,双槽沟托槽配合双圆丝(直径0.016英寸和0.018英寸)组合的滑动阻力并不比常规托槽和0.016英寸×0.022英寸方丝组合大.     

Prospective randomised controlled trial of an intramedullary nail versus a sliding hip screw for intertrochanteric fractures of the femur

Purpose

The purpose of this prospective randomised trial was to assess whether an intramedullary nail is superior to a sliding hip screw in the treatment of multifragmentary intertrochanteric fractures

Methods

Eighty patients with a 31-A2.2 or A2.3 Arbeitsgemeinschaft für Osteosynthesefragen/Orthopaedic Trauma Association (AO/OTA) intertrochanteric fracture were randomly allocated to fixation with either the Gamma nail or the AMBI sliding hip screw device.

Results

All patients were followed up at one, three, six and 12 months postoperatively, except for nine who died. There was no statistical difference in Parker mobility score between groups. The Gamma nail group had significantly higher Barthel Index and EuroQol-5D (EQ-5D) scores than the AMBI group at 12 months. At the same time, the EQ-5D score had returned to its pre-operative values in the Gamma nail group but not in the AMBI group. There were no differences in mortality, radiation time and hospital stay. Duration of the operation, incision length and hip pain occurrence were significantly less in the Gamma nail group.

Conclusions

Few failures occur when unstable 31-A2.2 and A2.3 AO/OTA fractures are fixed with a sliding hip screw. Nevertheless, an intramedullary nail seems superior in reconstituting patients to their pre-operative state.     

Diagnostic ultrasound assessment of deep fascia sliding mobility in vivo: A scoping review – Part 2: Femoral and crural fasciae

BackgroundFailure of fascial sliding may occur in cases of excessive or inappropriate use, trauma, or surgery, resulting in local inflammation, pain, sensitization, and potential dysfunction. Therefore, the mechanical properties of fascial tissues, including their mobility, have been evaluated in vivo by ultrasound (US) imaging. However, this seems to be a method that is not yet properly standardized nor validated.ObjectivesTo identify, synthesize, and collate the critical methodological principles that have been described in the literature for US evaluation of deep fascia sliding mobility in vivo in humans.MethodsA systematic literature search was conducted on ScienceDirect, PubMed (Medline), Web of Science and B-On databases, according to the PRISMA Extension for Scoping Reviews (PRISMA-ScR) guidelines. The OCEBM LoE was used to evaluate the level of evidence of each study.ResultsFrom a total of 104 full-text articles retrieved and assessed for eligibility, 18 papers were included that evaluate the deep fasciae of the thoracolumbar (n = 4), abdominal (n = 7), femoral (n = 4) and crural (n = 3) regions. These studies addressed issues concerning either diagnosis (n = 11) or treatment benefits (n = 7) and presented levels of evidence ranging from II to IV. Various terms were used to describe the outcome measures representing fascial sliding. Also, different procedures to induce fascial sliding, positioning of the individuals being assessed, and features of US devices were used. The US analysis methods included the comparison of start and end frames and the use of cross-correlation software techniques through automated tracking algorithms. These methods had proven to be reliable to measure sliding between TLF, TrA muscle-fascia junctions, fascia lata, and crural fascia, and the adjacent epimysial fascia. However, the papers presented heterogeneous terminologies, research questions, populations, and methodologies.This two-part paper reviews the evidence obtained for the thoracolumbar and abdominal fasciae (Part 1) and for the femoral and crural fasciae (Part 2).ConclusionThe US methods used to evaluate deep fascia sliding mobility in vivo in humans include the comparison of start and end frames and the use of cross-correlation software techniques through automated tracking algorithms. These seem reliable methods to measure sliding of some fasciae, but more studies need to be systematized to confirm their reliability for others. Moreover, specific standardized protocols are needed to assess each anatomical region as well as study if age, sex-related characteristics, body composition, or specific clinical conditions influence US results.