Amin Mohamadi

ENDOTOXEMIA IS ASSOCIATED WITH PARTIAL UNCOUPLING OF CARDIAC PACEMAKER FROM CHOLINERGIC NEURAL CONTROL IN RATS

ABSTRACT Cardiac cycle is regulated by a complex interplay between autonomic nervous system and cardiac pacemaker cells. Decreased heart rate variability (HRV) and increased cardiac rhythm regularity are associated with poor prognosis in patients with systemic inflammation (e.g., sepsis). However, the underlying mechanism of decreased HRV in systemic inflammation is not understood. It is known that greater regularity in a complex system could indicate uncoupling of the system’s components. The present study aimed to test the hypothesis that impaired responsiveness of cardiac pacemaker to autonomic nervous system may lead to uncoupling of the cardiovascular regulatory mechanisms during systemic inflammation. Systemic inflammation was induced by intraperitoneal injection of endotoxin (lipopolysaccharide, 1 mg/kg) in rats. Cardiovascular signals were recorded in conscious animals using a telemetric system. Heart rate dynamics was analyzed using Poincaré plot, and cardiac cycle regularity was assessed by sample entropy analysis. Spontaneously beating atria were isolated, and chronotropic responsiveness to adrenergic and cholinergic stimulation was assessed using standard organ bath. Sample entropy decreased significantly 4 h after endotoxin injection in conscious rats. Vagal modulation of cardiac cycle (as assessed by Poincaré plot) also exhibited a significant reduction in endotoxemic rats. Acute endotoxin challenge was associated with a significant hyporesponsiveness of isolated spontaneously beating atria to cholinergic stimulation. The chronotropic responsiveness to adrenergic stimulation was identical in controls and endotoxin-treated rats. These data propose that systemic inflammation is linked to reduced cardiac responsiveness to cholinergic stimulation. This may lead to partial uncoupling of cardiac pacemaker cells from autonomic neural control and can explain decreased HRV during systemic inflammation.

Personality characteristics in MS patients: The role of avoidant personality

OBJECTIVES Quality of life (QOL) is markedly affected by multiple sclerosis (MS). Particular personality characteristics (PC) of MS patients can affect their QOL. We designed the present study to determine the role of various PCs on QOL in MS patients accounting for other clinical factors. METHODS QOL, PC, physical disability, and mental status were recorded in 83 MS patients referred to two academic hospitals of Tehran University of Medical Sciences in 2011-2012. RESULTS The mean age of enrolled patients was 31.54±7.38 (range: 14-50) years and 74 (89.2%) were female. Mean disease duration was 4.55±4.70 years. Seventy-seven patients (92.8%) had relapsing-remitting disease, five (6%) had primary progressive, and one showed a secondary progressive course. Correlation between total QOL scores in MS patients and disease duration, cognitive impairment, and physical disability was significant (all p<0.001). Obsessive-compulsive personality was the most frequent PC (43.4%) in our patients. Only avoidant personality had a significant negative correlation with all components of QOL (Beta: 0.33, p<0.00). In addition, avoidant personality, physical disability, and mental status were found to be three predictors of QOL with all its components. CONCLUSION Avoidant personality appears to be an important predictor of poor QOL in MS patients. In addition, avoidant coping strategies appear to be associated with adverse response to stressful events in these patients. These findings suggest the need for psychological intervention for improving the coping strategies and QOL in MS patients.

Comparison of adverse events and postoperative mobilization following knee extensor mechanism rupture repair: A systematic review and network meta-analysis

BACKGROUND Extensor mechanism rupture (EMR) of the knee is a rare but potentially debilitating injury that often occurs due to trauma. While a wide variety of surgical treatments have been reported, there is currently no consensus on the most successful treatment method. The timing of post-operative joint mobilization is also critical for successful recovery after EMR repair. Despite the traditional method of complete immobilization for 6 weeks, there is an increasing trend towards early post-operative knee mobilization. The purpose of this network meta-analysis was to compare adverse event rates and function outcomes between repair methods and between post-operative mobilization protocols. METHODS MEDLINE, EMBASE, Web of Science, and Cochrane Central electronic databases were searched in August 2016 for observational studies involving repair of acute, traumatic EMRs. Data extraction included functional outcomes, adverse events, and additional surgeries. Cohort studies that were used in functional outcome analysis were assessed for risk of bias by the Newcastle-Ottawa Quality Assessment Scale (NOS). RESULTS Twenty-three studies (709 patients) were included for adverse event analysis. There were no significant differences in adverse event or additional surgery rates between EMR repair methods However, early mobilization produced significantly higher adverse event rates (p=0.02) and total event rates (p<0.001) than late mobilization, but the difference in additional surgery rates was not significant (p=0.06). Six studies (85 patients) were included for functional outcome analysis. There were no significant differences in thigh girth atrophy or muscle strength compared to the contralateral leg between patients treated with transosseous drill holes and simple end-to-end sutures. CONCLUSIONS We performed the first network meta-analysis to date comparing treatment of EMRs. Our results support the current body of knowledge that there is no single superior repair method. Although there is an increasing trend towards early or immediate post-operative knee mobilization, we found that early mobilization is associated with significantly higher adverse event and total event rates compared to fixed immobilization for a minimum of 6 weeks, implicating an increased financial burden and decreased quality of life associated with early post-operative mobilization.

Diagnostic Wrist Arthroscopy for Nonspecific Wrist Pain

Background: This study addresses the prevalence of discrete pathophysiology accounting for patients’ symptoms during diagnostic wrist arthroscopy in individuals with wrist pain without a specific preoperative diagnosis. Secondarily, we determined the number and type of surgeries subsequent to diagnostic wrist arthroscopy. Methods: Between January 2000 and January 2015, 135 diagnostic wrist arthroscopies were performed by 12 surgeons in 3 urban academic hospitals. We recorded the diagnostic findings of diagnostic wrist arthroscopy and any subsequent surgeries. Results: One hundred and five patients had synovitis or a normal wrist (78%), 17 had likely age-appropriate changes (eg, central triangular fibrocartilage complex defects scapholunate changes) (13%), 8 (6%) were given uncommon diagnoses, and 5 (4%) had osteochondral defects. Sixteen patients (12%) had subsequent wrist surgery: 2 were for adverse events, 2 were carpal tunnel releases, and 12 were other surgeries. Conclusion: Diagnostic arthroscopy performed in the setting of an unclear preoperative diagnosis yielded limited diagnostic benefit.

Completely displaced S-1/S-2 growth plate fracture in an adolescent: case report and review of literature.

In children, pelvic fractures are not common, and therefore, sacral fractures are a rare occurrence. Sacral fractures are often associated with neurologic deficit. Using radiographs alone may not be adequate to diagnose sacral fractures, and computed tomography scanning and/or magnetic resonance imaging may be needed. Treatment of the sacral fracture is often controversial and can range from nonoperative management to surgical intervention. This article presents a case report of completely displaced S-1/S-2 growth plate fracture. It also describes our diagnostic and treatment approach based on similar previously reported cases.

Different References for Valgus Cut Angle in Total Knee Arthroplasty

Background The valgus cut angle (VCA) of the distal femur in Total Knee Arthroplasty (TKA) is measured preoperatively on three-joint alignment radiographs. The anatomical axis of the femur can be described as the anatomical axis of the full length of the femur or as the anatomical axis of the distal half of the femur, which may result in different angles in some cases. During TKA, the anatomical axis of the femur is determined by intramedullary femoral guides, which may follow the distal half or near full anatomical axis, based on the length of the femoral guide. The aim of this study was to compare using the anatomical axis of the full length of the femur versus the anatomical axis of the distal half of the femur for measuring VCA, in normal and varus aligned femurs. We hypothesized that the VCA would be different based upon these two definitions of the anatomical axis of the femur. Methods Full-length weight bearing radiographs were used to determine three-joint alignment in normal aligned (Lateral Distal Femoral Angle; LDFA = 87º ± 2º) and varus aligned (LDFA >89º) femurs. Full-length anatomical axis-mechanical axis angle (angle 1) and distal half anatomical axis-mechanical axis angle (angle 2) were measured in all subjects by two independent orthopedic surgeons using a DICOM viewer software (PACS). Angles 1 and 2 were compared in normal and varus aligned subjects to determine whether there was a significant difference. Results Ninety-seven consecutive subjects with normally aligned femurs and 97 consecutive subjects with varus aligned femurs were included in this study. In normally aligned femurs, the mean value of angle 1 was 5.05° ± 0.76° and for angle 2 was 3.62° ± 1.19°, which were statistically different (P= 0.0001). In varus aligned femurs, the mean value of angle 1 was 5.42° ± 0.85° and for angle 2 was 4.23° ± 1.27°, which were also statistically different (P= 0.0047). Conclusion The two different methods of outlining the anatomical axis of the femur lead to different results in both normal and varus-aligned femurs. This should be considered in determination of the valgus cut angle on pre-operative radiographs and be adjusted according to the length of the intramedullary guide.

A systematic review and meta-analysis of arthroscopic assisted techniques for thumb carpometacarpal joint osteoarthritis

Arthroscopic management of thumb carpometacarpal (CMC) osteoarthrosis (OA) is an approach that has unclear results. We performed a systematic review encompassing three electronic databases up to May 2016 for studies describing arthroscopic-assisted techniques for thumb CMC OA. Meta-analyses of visual analogue scores (VAS) for pain, Disabilities of the Arm, Shoulder and Hand (DASH) scores, grip strength and pinch strength before and after arthroscopy were performed for ten included non-randomized cohort studies comprising 294 patients. Based on Hedges’ g measure, we found a large effect on VAS and DASH scores, a small effect on grip strength and no effect on pinch strength. On average, VAS improved by 4.1 cm, DASH by 22 points and grip strength by 2.8 kg. Complications were reported in 4% of patients. The use of arthroscopic-assisted techniques for thumb CMC OA is still limited; however, it may be a reasonable option for patients with thumb CMC OA who do not respond to non-operative treatment.

Chronic Scapholunate Interosseous Ligament Disruption: A Systematic Review and Meta-Analysis of Surgical Treatments

Background: Although many techniques have been described, there is no clear optimal surgical treatment for chronic scapholunate interosseous ligament (SLIL) disruption. Methods: We identified 255 articles reporting outcomes of SLIL reconstruction. Of these, 40 studies (978 wrists) met eligibility requirements and reported sufficient data on radiographic outcomes to be included in the study. The mean and standard deviation of preoperative and follow-up assessments including scapholunate gap (SLG) and scapholunate angle (SLA) were used to calculate pooled standardized mean differences (SMD) with 95% confidence intervals (CIs). For other radiographic or clinical outcomes, there were not enough reported data to calculate a pooled effect size, and pooled nonstandardized comparisons were made. Results: The SMD between preoperative and postoperative SLA in tenodesis reconstruction was 0.7 (CI, 0.29 to 1.11, P = .001) and 0.04 (CI, –0.27 to 0.38, P = .8) for capsulodesis reconstruction. For SLG, tenodesis demonstrated an SMD of 1.1 (CI, 0.6 to 1.55, P < .001) compared with 0.1 (CI, –0.36 to 0.59, P = .6) for capsulodesis reconstruction. Tenodesis had a significant improvement compared with capsulodesis in SLA (P = .01) and SLG (P = .005). Tenodesis also showed improvement in grip strength and Disabilities of the Arm, Shoulder and Hand scores. Conclusions: Comparing preoperative and postoperative radiographic measurements, tenodesis reconstruction demonstrated significantly improved SLG and SLA relative to capsulodesis. Interpreted in the context of the limitations, existing data demonstrates some benefit of tenodesis reconstruction.

Factors Influencing Treatment Recommendations For Base of 5th Metatarsal Fractures In Orthopaedic Residency Programs

Introduction/Purpose: Management of basilar 5th metatarsal fractures remains a controversial topic in orthopaedic surgery. Both operative and non-operative approaches have been described as potentially effective treatment strategies in the clinical setting. Non-operative approach is associated with higher non-union rates and longer times to union; however, operative intervention exposes patients to surgical risks. This confusion has led to non-standardized treatment recommendations for basilar 5th metatarsal fractures. This study was therefore designed to analyze whether or not orthopaedic trainees recommend treatment that differs from the treatments proposed by orthopaedic foot and ankle experts. Our hypothesis is that PGY-level does not improve concordance of treatment recommendation compared with orthopaedic foot and ankle specialists as a reflection of the varied treatment algorithms trainees are exposed to during residency training.

Rehabilitation following meniscal repair: a systematic review

Objective To review existing biomechanical and clinical evidence regarding postoperative weight-bearing and range of motion restrictions for patients following meniscal repair surgery. Methods and data sources Following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guideline, we searched MEDLINE using following search strategy: ((((“Weight-Bearing/physiology”[Mesh]) OR “Range of Motion, Articular”[Mesh]) OR “Rehabilitation”[Mesh])) AND (“Menisci, Tibial”[Mesh]). Additional articles were derived from previous reviews. Eligible studies were published in English and reported a rehabilitation protocol following meniscal repair on human. We summarised rehabilitation protocols and patients’ outcome among original studies. Results Seventeen clinical studies were included in this systematic review. There was wide variation in rehabilitation protocols among clinical studies. Biomechanical evidence from small cadaveric studies suggests that higher degrees of knee flexion and weight-bearing may be safe following meniscal repair and may not compromise the repair. An accelerated protocol with immediate weight-bearing at tolerance and early motion to non-weight-bearing with immobilising up to 6 weeks postoperatively is reported. Accelerated rehabilitation protocols are not associated with higher failure rates following meniscal repair. Conclusions There is a lack of consensus regarding the optimal postoperative protocol following meniscal repair. Small clinical studies support rehabilitation protocols that allow early motion. Additional studies are needed to better clarify the interplay between tear type, repair method and optimal rehabilitation protocol.