Acromial fractures following reverse shoulder arthroplasty: the role of the acromial morphology and a comparison of clinical outcomes.

BACKGROUND: The purpose was to evaluate the relationship between acromial morphology and the location of acromial fractures following reverse shoulder arthroplasty and determine whether fracture location and displacement impact clinical outcomes. METHODS: We performed a multicenter retrospective review of reverse shoulder arthroplasties complicated by acromial fractures. Radiographs were compared to determine the differences in acromial morphology, as well as fracture orientation and pattern, between patients with Levy type I (n = 17) and Levy type II (n = 25) fractures. Patients with a minimum of 2 years' follow-up were selected to examine the association between clinical outcomes and fracture location and displacement. Twenty-two patients were stratified based on whether they achieved the minimal clinically important difference (MCID) in the American Shoulder and Elbow Surgeons score (20 points). The groups were then compared regarding fracture location and displacement using measurements such as the acromiohumeral distance. RESULTS: The Levy type I group had a higher acromial slope than the Levy type II group (127° vs. 117°, P < .001). Levy type I fractures had a transverse pattern occurring in the coronal plane, whereas Levy type II fractures had an oblique pattern occurring in the sagittal plane (P < .001). At final follow-up, 12 of 22 patients (55%) achieved the MCID. Those who did not achieve the MCID had more displaced fractures including a lower acromiohumeral distance (8 mm vs. 20 mm, P = .007). There was no difference in the distribution of Levy type I and type II fractures based on the MCID cutoff (P = .093). CONCLUSION: An increased acromial slope is associated with transverse fractures in the Levy I region, whereas a lower acromial slope is associated with oblique fractures in the Levy II region. Overall, 55% of patients achieved the MCID at mid-term follow-up. The outcomes of those who did not achieve the MCID became worse postoperatively, and this was associated with increased fracture displacement.

A cohort comparison of humeral implant designs in reverse shoulder arthroplasty: does implant design lead to lower rates of complications and revision?

INTRODUCTION: The purpose of this study was to evaluate the outcomes, revisions, and complications between a first-generation cemented modular humeral implant and a second-generation monolithic, primarily uncemented humeral implant in reverse total shoulder arthroplasty with 135° neck-shaft angle and varying degrees of metallic glenosphere offsets. METHODS: We retrospectively evaluated patients undergoing reverse total shoulder arthroplasty from 2004 to 2014 with a first-generation cemented modular humeral implant (400 patients) or second-generation monolithic humeral stem (231 patients), who had at minimum 2-year clinical and radiographic follow-up. RESULTS: Both groups of patients had similar improvement of clinical outcomes (American Shoulder and Elbow Surgeons +30 points vs. +34 points, respectively) with improvements in all planes of motion (forward flexion +70° vs. +75°, abduction +61° vs. +71°, external rotation +23° vs. +22°, and internal rotation +1.6 vs. +1.5 level improvement, respectively). The incidence of humeral loosening for the cemented group was 3.6%, whereas in the uncemented group it was 0.4% (P = .01). A total of 28 shoulders treated with the cementing technique (4.0%) and 6 patients treated with the press-fit technique (1.5%) were revised (P = .028). The rate of postoperative acromial fractures within the first year was 3.4% in the cemented group and 1.8% in the uncemented group (P = .177). CONCLUSIONS: Both the first-generation cemented modular humeral stem implant and the second-generation monolithic humeral stem implant had equivalent clinical outcomes. In addition, with the monolithic stem primarily using press-fit fixation, there was a significant reduction in the incidence of radiographic loosening and the need for revision compared with a cemented stem.

In Vivo Image-Based 4D Modeling of Competent and Regurgitant Mitral Valve Dynamics.

BACKGROUND: In vivo characterization of mitral valve dynamics relies on image analysis algorithms that accurately reconstruct valve morphology and motion from clinical images. The goal of such algorithms is to provide patient-specific descriptions of both competent and regurgitant mitral valves, which can be used as input to biomechanical analyses and provide insights into the pathophysiology of diseases like ischemic mitral regurgitation (IMR). OBJECTIVE: The goal is to generate accurate image-based representations of valve dynamics that visually and quantitatively capture normal and pathological valve function. METHODS: We present a novel framework for 4D segmentation and geometric modeling of the mitral valve in real-time 3D echocardiography (rt-3DE), an imaging modality used for pre-operative surgical planning of mitral interventions. The framework integrates groupwise multi-atlas label fusion and template-based medial modeling with Kalman filtering to generate quantitatively descriptive and temporally consistent models of valve dynamics. RESULTS: The algorithm is evaluated on rt-3DE data series from 28 patients: 14 with normal mitral valve morphology and 14 with severe IMR. In these 28 data series that total 613 individual 3DE images, each 3D mitral valve segmentation is validated against manual tracing, and temporal consistency between segmentations is demonstrated. CONCLUSIONS: Automated 4D image analysis allows for reliable non-invasive modeling of the mitral valve over the cardiac cycle for comparison of annular and leaflet dynamics in pathological and normal mitral valves. Future studies can apply this algorithm to cardiovascular mechanics applications, including patient-specific strain estimation, fluid dynamics simulation, inverse finite element analysis, and risk stratification for surgical treatment.

Randomized prospective evaluation of the use of tranexamic acid and effects on blood loss for proximal humeral fracture surgery.

BACKGROUND: Tranexamic acid (TXA) is an antifibrinolytic agent that has been used to reduce blood loss in orthopedic surgery. It has been shown to decrease blood loss in upper- and lower-extremity arthroplasty, as well as lower-extremity fracture surgery. The use of TXA for proximal humeral fracture surgery has yet to be evaluated. The purpose of this study was to examine the effects of TXA on blood loss in patients undergoing open reduction-internal fixation (ORIF) or arthroplasty for the treatment of proximal humeral fractures. MATERIALS AND METHODS: A total of 101 patients were randomized to receive either a single preoperative dose of intravenous TXA (53 patients) or a control dose of saline solution (48 patients) at the time of proximal humeral fracture surgery. On the basis of patient age and fracture pattern, ORIF was performed in 57 patients (30 TXA and 27 control patients) and reverse shoulder arthroplasty (RSA) was performed in the other 44 patients (23 TXA and 21 control patients). Intraoperative blood loss plus 24-hour drain output was used to calculate total blood loss for each procedure. The preoperative-to-postoperative change in hemoglobin level was also evaluated for each patient. Further stratification of blood loss and change in hemoglobin level based on procedure (ORIF or RSA) was performed as well. RESULTS: Compared with the control group, the TXA group had less average intraoperative blood loss (178 mL vs. 129 mL, P < .0001), less postoperative drain output (103 mL vs. 62 mL, P < .0001), and less total blood loss (280 mL vs. 188 mL, P < .0001). Compared with the control group, the TXA group had a smaller average preoperative-to-postoperative change in hemoglobin level (-2.6 g/dL vs. -1.5 g/dL, P < .0001). Further stratification based on procedure showed that among patients undergoing ORIF and patients undergoing RSA, those receiving TXA had less average total blood loss and a smaller decrease in hemoglobin level than the control group. No identifiable intraoperative or postoperative complications associated with the use of TXA occurred in any patient. CONCLUSION: TXA was effective in reducing total blood loss and led to a smaller preoperative-to-postoperative decrease in hemoglobin level compared with control in patients undergoing surgery for proximal humeral fractures. This effect was consistent in patients treated with either ORIF or arthroplasty as the surgical procedure. TXA can be used to decrease blood loss in the surgical treatment of proximal humeral fractures.

The risk of postoperative scapular spine fracture following reverse shoulder arthroplasty is increased with an onlay humeral stem.

BACKGROUND: The purpose of this study was to assess the effects of lateralization and distalization on scapular spine fracture (SSF) after reverse shoulder arthroplasty (RSA). The hypothesis was that postoperative distalization would increase the risk of SSF, whereas lateralization would not. METHODS: A multicenter retrospective review was performed at a minimum of 1 year postoperatively on primary RSAs with 3 different implants, 2 with an inlay design (n = 342) and 1 with an onlay design (n = 84). Functional outcome, range of motion, stem design, and radiographic measurements, including acromiohumeral distance and lateralization, were compared between groups with and without fracture. RESULTS: The incidence of SSF in the onlay group (11.9%) was significantly higher compared with the inlay group (4.7%; P = .043). Postoperative acromiohumeral distance was approximately 4 mm higher in the SSF group (37.5 mm) compared with the control group (33.7 mm; P = .042), whereas lateralization was similar between the 2 groups (52.8 mm vs. 53.9 mm; P = .362). Higher return to activity (92.1% vs. 71.4%; P < .001) as well as postoperative forward flexion was observed in the group without fracture (135° vs. 120°; P = .009). CONCLUSION: Increased postoperative distalization is associated with an increased risk of SSF after RSA. An onlay stem resulted in a 10 mm increase in distalization compared with an inlay stem, and a 2.5 times increased risk of SSF. Lateralization, however, does not appear to increase the risk of SSF.

Defining the younger patient: age as a predictive factor for outcomes in shoulder arthroplasty.

BACKGROUND: The purpose of this study was to define an age cutoff at which clinical outcomes and revision rates differ for patients undergoing primary anatomic total shoulder arthroplasty (TSA) and patients undergoing primary reverse shoulder arthroplasty (RSA). METHODS: This retrospective cohort study included 1250 primary shoulder arthroplasties (1131 patients) with minimum 2-year clinical follow-up (mean, 50 months [range, 24-146 months]). TSA (n = 518; mean age, 68.1 years [range, 28-90 years]) was performed for osteoarthritis in most cases (99%), whereas the primary diagnoses for RSA (n = 732; mean age, 70.8 years [range, 22-91 years]) included rotator cuff arthropathy (35%), massive cuff tear without osteoarthritis (29.8%), and osteoarthritis (20.5%). Outcomes included range of motion, the American Shoulder and Elbow Surgeons (ASES) score, and the revision rate. The relationship between age at the time of surgery in 5-year increments (46-50 years, 51-55 years, and so on) and the revision rate was examined to identify the age cutoff; this was then used to assess clinical outcomes. RESULTS: In patients younger than 65 years, TSA was associated with a 3.4-fold increased risk of revision (P = .01). RSA performed in patients younger than 60 years was associated with a 4.8-fold increased risk of revision (P < .001). TSA patients aged 65 years or older and RSA patients aged 60 years or older had better total ASES scores (82 vs. 77 [P = .03] and 72 vs. 62 [P = .002], respectively) and better internal rotation (interquartile range, TSA 5-6 vs. 4-5 [P = .002] and RSA 4-5 vs 3-4 [P = .04])-where 6 represents T4 to T6 and 4 represents T11 to L1-than their younger counterparts. CONCLUSION: Age at index arthroplasty affects outcomes and the risk of revision. Primary TSA patients younger than 65 years and RSA patients younger than 60 years have a significantly increased revision risk. These age cutoffs are also correlated with differences in ASES scores and internal rotation.

Acute surgical management of proximal humerus fractures: ORIF vs. hemiarthroplasty vs. reverse shoulder arthroplasty.

BACKGROUND: Proximal humerus fracture treatment varies by surgeon preference and patient factors. This study compares patient and fracture characteristics, with outcomes between current surgical treatment options. METHODS: Between 1999 and 2018, 425 proximal humerus fractures underwent acute surgical management: open reduction internal fixation (ORIF, n = 211), hemiarthroplasty (HA, n = 108), or reverse shoulder arthroplasty (RSA, n = 106). Patient and fracture characteristics included age, American Society of Anesthesiologists physical status classification (ASA), and fracture classification. Postoperative motion at 3, 6, and minimum 12 months (avg 20 ± 21 months), radiographic outcomes, and postoperative falls were analyzed. RESULTS: Average age for treatment groups was 65 ± 13 years (range: 18-93 years). Fractures were classified as 2- (11%), 3- (41%), or 4-part (48%). Age, ASA, and fracture classification were associated with selected surgical management (P < .0001, =.001, <.0001, respectively). Outcomes showed a significant improvement in forward flexion from 3 months to 6 months in all groups (P < .0001). No difference in final motion was seen between groups. Radiographic union was higher in ORIF (89%), and similar between HA (79%) and RSA (77%, P = .005). Rate of reoperation was RSA 6.6%, ORIF 17.5%, and hemiarthroplasty 15.7% (P = .029). Postoperatively, 23% patients had at least 1 fall, of which 73% resulted in fractures. CONCLUSION: Older patients with high ASA were treated with arthroplasty, and younger patients with lower ASA were treated with ORIF. All groups showed improvements in motion. At minimum 1 year of follow-up, there was no difference in motion between groups. ORIF and HA showed significantly more reoperations compared with RSA. Patients should be counseled about reoperation, fall risk, and prevention.

Optimizing humeral stem fixation in revision reverse shoulder arthroplasty with the cement-within-cement technique.

BACKGROUND: The purpose of this study was to report on the clinical outcomes of patients undergoing revision reverse shoulder arthroplasty (RSA) by the cement-within-cement technique, as well as to identify whether surgical technique can affect subsequent humeral loosening. METHODS: In 98 patients, cemented humeral components that were revised to RSA using the cement-within-cement technique were identified and included in this study. We compared 8 patients in whom humeral stem loosening developed with 90 patients whose stem remained fixed. Preoperative and postoperative radiographs of each patient were downloaded in DICOM (Digital Imaging and Communications in Medicine) format and analyzed in Mimics. The total area of the cement mantle (in square millimeters) and of the stem (in square millimeters), as visualized on 2-dimensional plain films, was measured in each subject on both preoperative and postoperative radiographs. Outcomes at a minimum of 2 years of follow-up were analyzed. RESULTS: Clinical outcomes were available in 57 patients, with a mean follow-up period of 54 months (range, 21-156 months). Patients demonstrated significantly improved functional outcome scores and shoulder range of motion. In the group without loosening, the mean increase in the cement mantle area was 4380 ± 12701 mm2 (P < .0001). In the group with loosening, the mean increase in the cement mantle area was only 811 ± 4014 mm2 (P = .484). CONCLUSIONS: Use of the cement-within-cement technique for fixation of the humeral component in revision RSA is effective in improving functional outcome scores and shoulder range of motion. Furthermore, these findings suggest that efforts to maximize the cement volume during reimplantation may lessen the chance of humeral stem loosening requiring additional revision.

Use of a modified Outerbridge-Kashiwagi procedure for the treatment of posttraumatic elbow sequelae.

BACKGROUND: To review our 10-year experience treating posttraumatic sequelae of the elbow using a modified Outerbridge-Kashiwagi (O-K) procedure. METHODS: Twenty-one patients with posttraumatic sequelae of the elbow treated using the technique were evaluated clinically using the Mayo Elbow Performance Score, range of motion testing, and pain level. We noted the presence of preoperative and postoperative ulnar nerve symptoms, complications, and reoperations. Open contracture release was selected to address either removal of hardware or ulnar nerve pathology. RESULTS: At a mean of 39 months (range, 12-116 months), the Mayo Elbow Performance Score improved from 52 to 84 (P < .0001) and the mean arc of motion improved from 44° to 98° (P < .0001). At the final follow-up, 90% of patients reported no pain or mild pain, and 81% of patients had a satisfactory objective result. In 15 of 21 cases (71%), it was necessary to mobilize the ulnar nerve. After contracture release, 1 patient developed new onset ulnar nerve symptoms. Three patients underwent reoperation: 2 for recalcitrant contracture and 1 for new onset ulnar nerve symptoms. CONCLUSIONS: The mini-open O-K procedure is safe and effective in restoring function in patients with retained hardware and posttraumatic contracture. Posttraumatic arthritic patients often require both removal of hardware and neurolysis of the ulnar nerve. The mini-open O-K procedure allows complete access to the elbow joint, which facilitates release for both intrinsic and extrinsic contracture.

Patient-specific CFD simulation of intraventricular haemodynamics based on 3D ultrasound imaging.

BACKGROUND: The goal of this paper is to present a computational fluid dynamic (CFD) model with moving boundaries to study the intraventricular flows in a patient-specific framework. Starting from the segmentation of real-time transesophageal echocardiographic images, a CFD model including the complete left ventricle and the moving 3D mitral valve was realized. Their motion, known as a function of time from the segmented ultrasound images, was imposed as a boundary condition in an Arbitrary Lagrangian-Eulerian framework. RESULTS: The model allowed for a realistic description of the displacement of the structures of interest and for an effective analysis of the intraventricular flows throughout the cardiac cycle. The model provides detailed intraventricular flow features, and highlights the importance of the 3D valve apparatus for the vortex dynamics and apical flow. CONCLUSIONS: The proposed method could describe the haemodynamics of the left ventricle during the cardiac cycle. The methodology might therefore be of particular importance in patient treatment planning to assess the impact of mitral valve treatment on intraventricular flow dynamics.

Coupling between resting cerebral perfusion and EEG.

While several studies have investigated interactions between the electroencephalography (EEG) and functional magnetic resonance imaging BOLD signal fluctuations, less is known about the associations between EEG oscillations and baseline brain haemodynamics, and few studies have examined the link between EEG power outside the alpha band and baseline perfusion. Here we compare whole-brain arterial spin labelling perfusion MRI and EEG in a group of healthy adults (n = 16, ten females, median age: 27 years, range 21-48) during an eyes closed rest condition. Correlations emerged between perfusion and global average EEG power in low (delta: 2-4 Hz and theta: 4-7 Hz), middle (alpha: 8-13 Hz), and high (beta: 13-30 Hz and gamma: 30-45 Hz) frequency bands in both cortical and sub-cortical regions. The correlations were predominately positive in middle and high-frequency bands, and negative in delta. In addition, central alpha frequency positively correlated with perfusion in a network of brain regions associated with the modulation of attention and preparedness for external input, and central theta frequency correlated negatively with a widespread network of cortical regions. These results indicate that the coupling between average EEG power/frequency and local cerebral blood flow varies in a frequency specific manner. Our results are consistent with longstanding concepts that decreasing EEG frequencies which in general map onto decreasing levels of activation.

A Weaving Rip-Stop Technique Leads to a Significantly Increased Load to Failure and Reduction in Suture-Tendon Cut-Through in a Biomechanical Model of Rotator Cuff Repair.

PURPOSE: To present an alternative arthroscopic rip-stop technique with a single suture tape weaved through the tendon from anterior to posterior and to biomechanically test its strength against a control technique consisting of a single-row repair with simple sutures. METHODS: This was a controlled biomechanical study. Dissection and harvesting of the supraspinatus muscle-tendon unit were performed along the cable in 9 matched-pair cadaveric shoulders. Samples were divided into 2 groups: simple suture repair only (SSR) and simple suture repair with rip-stop (SSPR). Biomechanical testing was performed with an initial preload, followed by cyclic loading and then ramp to failure. Peak-to-peak displacement, stiffness (in newtons per millimeter), load at failure (in newtons), and failure mechanism were recorded. Data were compared using the paired-sample t test. RESULTS: The average peak-to-peak displacement for SSR samples was not significantly different from that of SSPR samples (P = .96). Similarly, elongation in the SSR and SSPR groups was not significantly different (P = .82). Stiffness was significantly different between the SSR and SSPR groups (P = .0054): SSR samples were less stiff than SSPR samples. Moreover, SSR samples failed at significantly lower forces than did SSPR samples (P = .028). A larger percentage of failures occurred due to tendon cut-through among SSR samples versus suture breakage among SSPR samples. CONCLUSIONS: An alternative rip-stop technique is presented in this biomechanical model that may assist surgeons to better deal with difficult rotator cuff repairs. Weaving a suture tape as a rip-stop can increase stiffness, achieve higher failure loads when compared with simple suture repair with no rip-stop, and reduce tendon cut-through. CLINICAL RELEVANCE: This study provides insight into a variation of rip-stop stitch techniques that may help solve the clinical problem of failure occurring at the suture-tendon interface, specifically tendon cut-through.

Alterations in Intracardiac Flow Patterns Affect Mitral Leaflets Dynamics in a Model of Ischemic Mitral Regurgitation.

PURPOSE: This study was to evaluate the effects of ischemic mitral regurgitation (IMR) on vortex formation and leaflet dynamics using an established porcine infarct model of IMR. METHODS: Using direct coronary ligation, five animals were subjected to a posterolateral myocardial infarction (MI) followed by an MRI at 12-weeks post MI. MR imaging consisted of 4D time-resolved left ventricular (LV) flow, full coverage 2D LV cine, and high resolution 2D cine of mitral valve dynamics. Five additional naïve animals underwent identical imaging protocols to serve as controls. Image analysis was performed to obtain mitral transvalvular flows as well as LV volumes throughout the cardiac cycle. In addition, anterior to posterior mid-leaflet tip distances were measured throughout the cardiac cycle for determination of temporal leaflet dynamics. RESULTS: It was found IMR caused asymmetric vortex ring formation with the anterior vortex having a lower vorticity relative to its posterior counterpart. In contrast, normal ventricles create symmetric and tightly curled vortices in the basal chamber just underneath the mitral leaflets which conserve kinetic energy and aid in effective ejection. IMR animals were also evaluated for leaflet separation and were found to have a greater leaflet opening and achieved peak vorticity and peak leaflet opening later than control animals. CONCLUSION: In conclusion, this study shows the effects that altered vortex formation, due to IMR, can have on ventricular filling and leaflet dynamics. These findings have important implications for understanding blood flow through the dilated heart and how ring annuloplasty and volume reduction interventions may influence mitral valve dynamics.

Rabies is still a fatal but neglected disease: a case report.

BACKGROUND: Rabies, caused by a lyssavirus, is a viral zoonosis that affects people in many parts of the world, especially those in low income countries. Contact with domestic animals, especially dogs, is the main source of human infections. Humans may present with the disease only after a long period of exposure. Nearly half of rabies cases occur in children <15 years old. We report on a fatal case of rabies in a Ghanaian school child 5 years after the exposure incident, and the vital role of molecular tools in the confirmation of the diagnosis. CASE PRESENTATION: The patient, an 11-year-old junior high school Ghanaian student from the Obuasi Municipality in Ghana, presented with aggressive behavior, which rapidly progressed to confusion and loss of consciousness within a day of onset. Her parents reported that the patient had experienced a bite from a stray dog on her right leg 5 years prior to presentation, for which no antirabies prophylaxis was given. The patient died within minutes of arrival in hospital (within 24 hours of symptom onset). Real-time polymerase chain reaction testing of cerebrospinal fluid obtained after her death confirmed the diagnosis of rabies. Subsequent phylogenetic analysis showed the virus to belong to the Africa 2 lineage of rabies viruses, which is one of the predominant circulating lineages in Ghana. CONCLUSION: The incubation period of rabies is highly variable so patients may only present with symptoms long after the exposure incident. Appropriate molecular testing tools, when available as part of rabies control programmes, are vital in confirming cases of rabies.

Creating value in depression management.

BACKGROUND: in the current healthcare system in the USA, common mental health conditions are frequently undertreated. As a result, unacceptable disability, morbidity and mortality rates occur. Various stakeholders define, provide, monitor and may reward providers of mental health care, but based on differing interests and agendas. Examples of the implementation of evidence-based practice in general care, accompanied by changes in fiscal incentives, are rare outside of research endeavours. METHODS: we review as a case study a Minnesota state-wide effort to introduce collaborative care into 80 primary care clinics in order to improve the outcomes of depressed patients. This effort has been named the DIAMOND project (Depression Initiative Across Minnesota, Offering a New Direction) and it may illustrate several key steps towards creating value at the interface between primary care and specialty mental health care. Outcomes were defined and will be examined for a three-year period from when the initiative began in March 2008. RESULTS: to date the results are encouraging. All 80 clinics have introduced a new measurement tool into their practices, trained and hired care managers, and have developed an ongoing relationship with a psychiatrist. Over 4800 patients have been screened for depression, have received treatment and have been followed to ensure compliance and better outcomes. Remission rates (averaging 27%) are at levels comparable to research studies which have more stringent inclusion and exclusion criteria. Challenges including the loss of eligible patients are described. CONCLUSION: to create value in depression management, not only was a viable model required, but also a process for implementation and a structure for ongoing support of the model. The case study presented offers lessons that might be applied elsewhere toward creating value at the mental health and primary care interface.

Cyclic adenosine monophosphate: function in photoreceptors.

Inactivation of adenylate cyclase in outer segments of retinal photoreceptor cells is proportional to the bleaching of rhodopsin. Membranes of the outer segments also contain a particulate, light-insensitive phosphodiesterase of high specific activity. In electrophysiological experiments, application of cyclic adenosine monophosphate along with a methylxanthine mimics the effects of illumination on the photoreceptor cell of the compound eye of Limulus.

Digitonin effects on photoreceptor adenylate cyclase.

Adenylate cyclase is described in a number of photoreceptor membranes. Vertebrate rod outer segments contain light-regulated cyclase, and light regulation is abolished by digitonin. Disruption of microvilli in cone and rhabdomphotoreceptors is also associated with loss of light regulation and retention of full enzymic activity. The data suggest that inhibitory constraint provides regulation in cyclase systems and that disruption of membrane structure uncouples catalytic and regulatory elements.

Osteomyelitis of the ulnar head in a presumed "pulled elbow".

The "pulled elbow" is a common emergency department diagnosis that presents with a classic history and examination. A differential diagnosis should be sought in all children with atypical clinical features or in those in whom manipulation is unsatisfactory. The importance of follow-up should also be highlighted in the atypical pulled elbow. An unusual presentation of osteomyelitis of the ulnar head initially diagnosed as a pulled elbow in a 9-month-old boy is discussed. This case was further complicated by the lack of inflammatory response to infection and the manifestation clinically of signs apparently within the elbow rather than the osteomyelitic inferior radioulnar joint.

Effect of Nail Size, Insertion, and Δ Canal-Nail on the Development of a Nonunion After Intramedullary Nailing of Femoral Shaft Fractures.

OBJECTIVE: To determine whether intramedullary nail (IMN) diameter, antegrade versus retrograde insertion, or the difference between the canal and IMN diameter affect femoral shaft fracture healing. DESIGN: Retrospective analysis of a prospective database. SETTING: Level One Regional Trauma Center. PATIENTS/PARTICIPANTS: Seven hundred thirty-three femoral shaft fractures (OTA/AO 32) treated with an IMN between 1999 and 2017. After exclusion criteria, 484 fractures remained in the final analysis. INTERVENTION: Closed section, cannulated, interlocked, titanium alloy IMN using a reamed insertion technique. MAIN OUTCOME MEASUREMENTS: Nonunion, IMN size (10, 11.5, and 13 mm), antegrade versus retrograde insertion, Δ canal-nail diameter (ΔD) after reaming (<1, 1-2, or >2 mm). RESULTS: IMN diameters used were as follows: 314/10 mm (64%), 137/11.5 mm (28%), and 33/13 mm (8%). Forty-five percent were placed in antegrade versus 55% retrograde. Four hundred fifty-six fractures (94.2%) healed uneventfully. There were no IMN failures. 10/484 IMNs (2%) had broken interlocking screws; only 4 were associated with a NU. Average time to union was 23 weeks (12-119). Twenty-eight (5.8%) developed NU. There was no statistical correlation between (1) the NU rate and IMN diameter: 10 mm, 6.3%; 11.5 mm, 5.1%; 13 mm, 3% (P = 0.8, power = 0.85), (2) the NU rate and ΔD: 7.1% <1 mm, 5.6% 1-2 mm, 20% >2 mm (P = 0.36), (3) the NU rate and fracture location: Prox = 11%, Mid = 5%, Dist = 3% (P = 0.13), or (4) the NU rate and antegrade (7.2%) versus retrograde (4.2%) insertion (P = 0.24). CONCLUSION: Similar healing rates occurred regardless of IMN diameter, Δ canal-nail diameter after reaming, or insertion site. This indicates that a closed section, cannulated, interlocked, titanium alloy IMN with a diameter of 10 mm can be considered the standard diameter for the treatment of acute femoral shaft fractures, regardless of entry point. This should be associated with less reaming and therefore shorter operative times, and possibly less hospital implant inventories as well. Larger diameter IMN should be reserved for revision surgery. LEVEL OF EVIDENCE: Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.

Choice of antenatal testing significantly effects a patient's work obligations.

OBJECTIVE: We sought to compare two approaches to antenatal testing for their impact on the workforce. STUDY DESIGN: This is a prospective observational study of women who presented for antenatal testing. All women were given a survey upon presentation. As per hospital protocol, nonstress testing (NST) was performed semiweekly and biophysical profile (BPP) was performed weekly. The choice of testing was determined by the attending physician. chi2- and Student's t-tests were performed where appropriate. A P-value of <0.05 was considered significant. RESULT: A total of 195 women were surveyed. Among them, 94 women had an NST and 101 had a BPP. Overall, 59.2% were multiparous, 33.1% had to arrange for child care and 97.2% felt reassured by the testing. There were no differences in demographic characteristics, education, type of insurance or employment status between the groups. Women who had NSTs were more likely to lose time from work than those who had BPPs (218.4 versus 68.9 min; P<0.001). Of the women who had semiweekly NSTs, 80.6% would have preferred weekly testing. If the 94 women who received semiweekly testing had weekly testing, a total of 534.4 h would have been available for the workforce. CONCLUSION: Twice-weekly NST results in a significant increase in time lost from the workforce compared with weekly BPP.