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1.
Bone Joint J ; 103-B(9): 1552, 2021 Sep.
Article in English | MEDLINE | ID: mdl-34465161
2.
Bone Joint J ; 101-B(7_Supple_C): 48-54, 2019 07.
Article in English | MEDLINE | ID: mdl-31256639

ABSTRACT

AIMS: The outcomes of total knee arthroplasty (TKA) depend on many factors. The impact of implant design on patient-reported outcomes is unknown. Our goal was to evaluate the patient-reported outcomes and satisfaction after primary TKA in patients with osteoarthritis undergoing primary TKA using five different brands of posterior-stabilized implant. PATIENTS AND METHODS: Using our institutional registry, we identified 4135 patients who underwent TKA using one of the five most common brands of implant. These included Biomet Vanguard (Zimmer Biomet, Warsaw, Indiana) in 211 patients, DePuy/Johnson & Johnson Sigma (DePuy Synthes, Raynham, Massachusetts) in 222, Exactech Optetrak Logic (Exactech, Gainesville, Florida) in 1508, Smith & Nephew Genesis II (Smith & Nephew, London, United Kingdom) in 1415, and Zimmer NexGen (Zimmer Biomet) in 779 patients. Patients were evaluated preoperatively using the Knee Injury and Osteoarthritis Outcome Score (KOOS), Lower Extremity Activity Scale (LEAS), and 12-Item Short-Form Health Survey questionnaire (SF-12). Demographics including age, body mass index, Charlson Comorbidity Index, American Society of Anethesiologists status, sex, and smoking status were collected. Postoperatively, two-year KOOS, LEAS, SF-12, and satisfaction scores were compared between groups. RESULTS: Outcomes were available for 4069 patients (98%) at two years postoperatively. In multiple regression analysis, which separately compared each implant group with the aggregate of all others, there were no clinically significant differences in the change of KOOS score from baseline to two-year follow-up between any of the groups. More than 80% of patients in each group were satisfied at this time in all domains. In a multivariate regression model, patients in the NexGen group were the most likely to be satisfied (odds ratio (OR) 1.63; p = 0.006) and Optetrak Logic patients were the least likely to be satisfied (OR 0.60; p < 0.001). CONCLUSION: TKA provides improvement in function and satisfaction regardless of the type of implant. We could not demonstrate superiority of one design above others across these groups of implants, and any price premium for one above the other systems may not be justified. Healthcare administrators may find these similarities in outcomes helpful when negotiating purchasing contracts. Cite this article: Bone Joint J 2019;101-B(7 Supple C):48-54.


Subject(s)
Arthroplasty, Replacement, Knee/methods , Knee Joint/surgery , Knee Prosthesis , Osteoarthritis, Knee/surgery , Patient Reported Outcome Measures , Range of Motion, Articular/physiology , Recovery of Function/physiology , Aged , Female , Follow-Up Studies , Humans , Knee Joint/physiopathology , Male , Middle Aged , Osteoarthritis, Knee/diagnosis , Osteoarthritis, Knee/physiopathology , Prosthesis Design , Registries , Retrospective Studies , Surveys and Questionnaires , Time Factors , Treatment Outcome
3.
Bone Joint J ; 101-B(7_Supple_C): 10-16, 2019 07.
Article in English | MEDLINE | ID: mdl-31256650

ABSTRACT

AIMS: Tranexamic acid (TXA) is proven to reduce blood loss following total knee arthroplasty (TKA), but there are limited data on the impact of similar dosing regimens in revision TKA. The purpose of this multicentre randomized clinical trial was to determine the optimal regimen to maximize the blood-sparing properties of TXA in revision TKA. PATIENTS AND METHODS: From six-centres, 233 revision TKAs were randomized to one of four regimens: 1 g of intravenous (IV) TXA given prior to the skin incision, a double-dose regimen of 1 g IV TXA given both prior to skin incision and at time of wound closure, a combination of 1 g IV TXA given prior to skin incision and 1 g of intraoperative topical TXA, or three doses of 1950 mg oral TXA given two hours preoperatively, six hours postoperatively, and on the morning of postoperative day one. Randomization was performed based on the type of revision procedure to ensure equivalent distribution among groups. Power analysis determined that 40 patients per group were necessary to identify a 1 g/dl difference in the reduction of haemoglobin postoperatively between groups with an alpha of 0.05 and power of 0.80. Per-protocol analysis involved regression analysis and two one-sided t-tests for equivalence. RESULTS: In total, one patient withdrew, five did not undergo surgery, 16 were screening failures, and 25 did not receive the assigned treatment, leaving 186 patients for analysis. There was no significant difference in haemoglobin reduction among treatments (2.8 g/dl for single-dose IV TXA, 2.6 g/dl for double-dose IV TXA, 2.6 g/dl for combined IV/topical TXA, 2.9 g/dl for oral TXA; p = 0.38). Similarly, calculated blood loss (p = 0.65) and transfusion rates (p = 0.95) were not significantly different between groups. Equivalence testing assuming a 1 g/dl difference in haemoglobin change as clinically relevant showed that all possible pairings were statistically equivalent. CONCLUSION: Despite the higher risk of blood loss in revision TKA, all TXA regimens tested had equivalent blood-sparing properties. Surgeons should consider using the lowest effective dose and least costly TXA regimen in revision TKA. Cite this article: Bone Joint J 2019;101-B(Supple 7):10-16.


Subject(s)
Arthroplasty, Replacement, Knee/methods , Blood Loss, Surgical/prevention & control , Postoperative Hemorrhage/prevention & control , Tranexamic Acid/administration & dosage , Antifibrinolytic Agents/administration & dosage , Drug Administration Routes , Female , Follow-Up Studies , Hemoglobins/metabolism , Humans , Male , Middle Aged , Reoperation , Retrospective Studies , Treatment Outcome
4.
Bone Joint J ; 101-B(7): 808-816, 2019 07.
Article in English | MEDLINE | ID: mdl-31256658

ABSTRACT

There remains confusion in the literature with regard to the spinopelvic relationship, and its contribution to ideal acetabular component position. Critical assessment of the literature has been limited by use of conflicting terminology and definitions of new concepts that further confuse the topic. In 2017, the concept of a Hip-Spine Workgroup was created with the first meeting held at the American Academy of Orthopedic Surgeons Annual Meeting in 2018. The goal of this workgroup was to first help standardize terminology across the literature so that as a topic, multiple groups could produce literature that is immediately understandable and applicable. This consensus review from the Hip-Spine Workgroup aims to simplify the spinopelvic relationship, offer hip surgeons a concise summary of available literature, and select common terminology approved by both hip surgeons and spine surgeons for future research. Cite this article: Bone Joint J 2019;101-B:808-816.


Subject(s)
Arthroplasty, Replacement, Hip/methods , Pelvic Bones/physiology , Spine/physiology , Arthroplasty, Replacement, Hip/instrumentation , Humans , Patient Selection , Postoperative Complications/etiology , Postoperative Complications/prevention & control , Range of Motion, Articular , Risk Factors
5.
Int J Tuberc Lung Dis ; 23(3): 306-314, 2019 03 01.
Article in English | MEDLINE | ID: mdl-30871661

ABSTRACT

BACKGROUND: Tuberculosis (TB) diagnosis in human immunodeficiency virus (HIV) positive persons is difficult, particularly in resource-limited settings. The relationship between TB culture status and mortality in HIV-positive persons treated for TB is unclear. METHODS: We evaluated HIV-positive adults treated for TB at or after their first HIV clinic visit in Argentina, Brazil, Chile, Honduras, Mexico or Peru from 2000 to 2015. Anti-tuberculosis treatment included 2 months of isoniazid, rifampicin (RMP)/rifabutin (RBT), pyrazinamide ± ethambutol, followed by continuation phase treatment with isoniazid + RMP/RBT. RESULTS: Of 759 TB-HIV patients, 238 (31%) were culture-negative, 228 (30%) had unknown culture status or did not undergo culture and 293 (39%) were culture-positive. The median CD4 at TB diagnosis was 96 (interquartile range 40-228); 636 (84%) received concurrent antiretroviral therapy (ART) and anti-tuberculosis treatment. There were 123 (16%) deaths: 90/466 (19%) with TB culture-negative, unknown or not performed vs. 33/293 (11%) who were TB culture-positive (P = 0.005). In Kaplan-Meier analysis, mortality in TB patients without culture-confirmed disease was higher (P = 0.002). In a Cox model adjusted for age, sex, CD4, ART timing, disease site and stratified by study site, mortality in persons without culture-confirmed TB was not significantly increased compared to those with culture-positive TB (hazard ratio 1.39, 95%CI 0.89-2.16, P = 0.15). CONCLUSION: Most HIV-positive patients treated for TB did not have culture-confirmed TB, and mortality tended to be higher in patients without culture-confirmed disease, although the association was not statistically different after adjusting for other variables. Accurate TB diagnosis in HIV-positive persons is crucial.


Subject(s)
Anti-HIV Agents/administration & dosage , Antitubercular Agents/administration & dosage , HIV Infections/complications , Tuberculosis/diagnosis , Adult , CD4 Lymphocyte Count , Female , HIV Infections/drug therapy , HIV Infections/mortality , Humans , Latin America , Male , Tuberculosis/drug therapy
6.
Bone Joint J ; 100-B(10): 1330-1335, 2018 10.
Article in English | MEDLINE | ID: mdl-30295528

ABSTRACT

AIMS: The aim of this study was to evaluate the surface damage, the density of crosslinking, and oxidation in retrieved antioxidant-stabilized highly crosslinked polyethylene (A-XLPE) tibial inserts from total knee arthroplasty (TKA), and to compare the results with a matched cohort of standard remelted highly crosslinked polyethylene (XLPE) inserts. MATERIALS AND METHODS: A total of 19 A-XLPE tibial inserts were retrieved during revision TKA and matched to 18 retrieved XLPE inserts according to the demographics of the patients, with a mean length of implantation of 15 months (1 to 42). The percentage areas of PE damage on the articular surfaces and the modes of damage were measured. The density of crosslinking of the PE and oxidation were measured at loaded and unloaded regions on these surfaces. RESULTS: A-XLPE inserts had higher rates of burnishing and lower rates of pitting and scratching compared with XLPE. There were no differences in the density of crosslinking at loaded and unloaded regions. A-XLPE showed higher oxidation indices in the unloaded surface region compared with XLPE. There were no differences in the levels of oxidation in the loaded regions. CONCLUSION: Retrieval analysis of A-XLPE did not reflect a clinically relevant difference in surface damage, density of crosslinking, or oxidation compared with XLPE tibial inserts at short-term evaluation. Cite this article: Bone Joint J 2018;100-B:1330-5.


Subject(s)
Antioxidants , Arthroplasty, Replacement, Knee/instrumentation , Knee Prosthesis , Polyethylene , Prosthesis Failure , Adult , Aged , Aged, 80 and over , Device Removal , Female , Follow-Up Studies , Humans , Male , Middle Aged , Oxidation-Reduction , Prosthesis Design , Reoperation , Retrospective Studies
7.
Bone Joint J ; 100-B(10): 1289-1296, 2018 Oct.
Article in English | MEDLINE | ID: mdl-30295534

ABSTRACT

AIMS: The aims of this study were to measure sagittal standing and sitting lumbar-pelvic-femoral alignment in patients before and following total hip arthroplasty (THA), and to consider what preoperative factors may influence a change in postoperative pelvic position. PATIENTS AND METHODS: A total of 161 patients were considered for inclusion. Patients had a mean age of the remaining 61 years (sd 11) with a mean body mass index (BMI) of 28 kg/m2 (sd 6). Of the 161 patients, 82 were male (51%). We excluded 17 patients (11%) with spinal conditions known to affect lumbar mobility as well as the rotational axis of the spine. Standing and sitting spine-to-lower-limb radiographs were taken of the remaining 144 patients before and one year following THA. Spinopelvic alignment measurements, including sacral slope, lumbar lordosis, and pelvic incidence, were measured. These angles were used to calculate lumbar spine flexion and femoroacetabular hip flexion from a standing to sitting position. A radiographic scoring system was used to identify those patients in the series who had lumbar degenerative disc disease (DDD) and compare spinopelvic parameters between those patients with DDD (n = 38) and those who did not (n = 106). RESULTS: Following THA, patients sat with more anterior pelvic tilt (mean increased sacral slope 18° preoperatively versus 23° postoperatively; p = 0.001) and more lumbar lordosis (mean 28° preoperatively versus 35° postoperatively; p = 0.001). Preoperative change in sacral slope from standing to sitting (p = 0.03) and the absence of DDD (p = 0.001) correlated to an increased change in postoperative sitting pelvic alignment. CONCLUSION: Sitting lumbar-pelvic-femoral alignment following THA may be driven by hip arthritis and/or spinal deformity. Patients with DDD and fixed spinopelvic alignment have a predictable pelvic position one year following THA. Patients with normal spines have less predictable postoperative pelvic position, which is likely to be driven by hip stiffness. Cite this article: Bone Joint J 2018;100-B:1289-96.


Subject(s)
Arthroplasty, Replacement, Hip , Bone Malalignment/etiology , Femur , Lumbar Vertebrae , Pelvic Bones , Postoperative Complications/etiology , Posture , Adult , Aged , Bone Malalignment/diagnostic imaging , Bone Malalignment/physiopathology , Cross-Sectional Studies , Female , Femur/diagnostic imaging , Femur/physiopathology , Humans , Lumbar Vertebrae/diagnostic imaging , Lumbar Vertebrae/physiopathology , Male , Middle Aged , Pelvic Bones/diagnostic imaging , Pelvic Bones/physiopathology , Postoperative Complications/diagnostic imaging , Postoperative Complications/physiopathology , Preoperative Period , Range of Motion, Articular , Risk Factors
8.
Bone Joint J ; 100-B(10): 1303-1309, 2018 10.
Article in English | MEDLINE | ID: mdl-30295538

ABSTRACT

AIMS: The aim of this study was to evaluate the accuracy of implant placement when using robotic assistance during total hip arthroplasty (THA). PATIENTS AND METHODS: A total of 20 patients underwent a planned THA using preoperative CT scans and robotic-assisted software. There were nine men and 11 women (n = 20 hips) with a mean age of 60.8 years (sd 6.0). Pelvic and femoral bone models were constructed by segmenting both preoperative and postoperative CT scan images. The preoperative anatomical landmarks using the robotic-assisted system were matched to the postoperative 3D reconstructions of the pelvis. Acetabular and femoral component positions as measured intraoperatively and postoperatively were evaluated and compared. RESULTS: The system reported accurate values for reconstruction of the hip when compared to those measured postoperatively using CT. The mean deviation from the executed overall hip length and offset were 1.6 mm (sd 2.9) and 0.5 mm (sd 3.0), respectively. Mean combined anteversion was similar and correlated between intraoperative measurements and postoperative CT measurements (32.5°, sd 5.9° versus 32.2°, sd 6.4°; respectively; R2 = 0.65; p < 0.001). There was a significant correlation between mean intraoperative (40.4°, sd 2.1°) acetabular component inclination and mean measured postoperative inclination (40.12°, sd 3.0°, R2 = 0.62; p < 0.001). There was a significant correlation between mean intraoperative version (23.2°, sd 2.3°), and postoperatively measured version (23.0°, sd 2.4°; R2 = 0.76; p < 0.001). Preoperative and postoperative femoral component anteversion were significantly correlated with one another (R2 = 0.64; p < 0.001). Three patients had CT scan measurements that differed substantially from the intraoperative robotic measurements when evaluating stem anteversion. CONCLUSION: This is the first study to evaluate the success of hip reconstruction overall using robotic-assisted THA. The overall hip reconstruction obtained in the operating theatre using robotic assistance accurately correlated with the postoperative component position assessed independently using CT based 3D modelling. Clinical correlation during surgery should continue to be practiced and compared with observed intraoperative robotic values. Cite this article: Bone Joint J 2018;100-B:1303-9.


Subject(s)
Arthroplasty, Replacement, Hip/methods , Hip Prosthesis , Osteoarthritis, Hip/surgery , Robotic Surgical Procedures/methods , Surgery, Computer-Assisted/methods , Aged , Arthroplasty, Replacement, Hip/instrumentation , Female , Follow-Up Studies , Humans , Imaging, Three-Dimensional , Male , Middle Aged , Osteoarthritis, Hip/diagnostic imaging , Prospective Studies , Tomography, X-Ray Computed
9.
Epidemiol Infect ; 146(10): 1308-1311, 2018 07.
Article in English | MEDLINE | ID: mdl-29843838

ABSTRACT

We aimed to quantify the proportion of people receiving care for HIV-infection that are 50 years or older (older HIV patients) in Latin America and the Caribbean between 2000 and 2015 and to estimate the contribution to the growth of this population of people enrolled before (<50yo) and after 50 years old (yo) (⩾50yo). We used a series of repeated, cross-sectional measurements over time in the Caribbean, Central and South American network (CCASAnet) cohort. We estimated the percentage of patients retained in care each year that were older HIV patients. For every calendar year, we divided patients into two groups: those who enrolled before age 50 and after age 50. We used logistic regression models to estimate the change in the proportion of older HIV patients between 2000 and 2015. The percentage of CCASAnet HIV patients over 50 years had a threefold increase (8% to 24%) between 2000 and 2015. Most of the growth of this population can be explained by the increasing proportion of people that enrolled before 50 years and aged in care. These changes will impact needs of care for people living with HIV, due to multiple comorbidities and high risk of disability associated with aging.


Subject(s)
Anti-HIV Agents/therapeutic use , HIV Infections/drug therapy , Adult , Age Distribution , Caribbean Region , Demography/trends , Female , Humans , Latin America , Male , Middle Aged
10.
Int J Infect Dis ; 63: 57-63, 2017 Oct.
Article in English | MEDLINE | ID: mdl-28807740

ABSTRACT

BACKGROUND: Cryptococcal meningitis (CM) is associated with substantial mortality in HIV-infected patients. Optimal timing of antiretroviral therapy (ART) in persons with CM represents a clinical challenge, and the burden of CM in Latin America has not been well described. Studies suggest that early ART initiation is associated with higher mortality, but data from the Americas are scarce. METHODS: HIV-infected adults in care between 1985-2014 at participating sites in the Latin America (the Caribbean, Central and South America network (CCASAnet)) and the Vanderbilt Comprehensive Care Clinic (VCCC) and who had CM were included. Survival probabilities were estimated. Risk of death when initiating ART within the first 2 weeks after CM diagnosis versus initiating between 2-8 weeks was assessed using dynamic marginal structural models adjusting for site, age, sex, year of CM, CD4 count, and route of HIV transmission. FINDINGS: 340 patients were included (Argentina 58, Brazil 138, Chile 28, Honduras 27, Mexico 34, VCCC 55) and 142 (42%) died during the observation period. Among 151 patients with CM prior to ART 56 (37%) patients died compared to 86 (45%) of 189 with CM after ART initiation (p=0.14). Patients diagnosed with CM after ART had a higher risk of death (p=0.03, log-rank test). The probability of survival was not statistically different between patients who started ART within 2 weeks of CM (7/24, 29%) vs. those initiating between 2-8 weeks (14/53, 26%) (p=0.96), potentially due to lack of power. INTERPRETATION: In this large Latin-American cohort, patients with CM had very high mortality rates, especially those diagnosed after ART initiation. This study reflects the overwhelming burden of CM in HIV-infected patients in Latin America.


Subject(s)
HIV Infections/mortality , Meningitis, Cryptococcal/epidemiology , Adult , Americas/epidemiology , Anti-Retroviral Agents/therapeutic use , CD4 Lymphocyte Count , Female , Follow-Up Studies , HIV Infections/drug therapy , HIV Infections/transmission , Humans , Male , Meningitis, Cryptococcal/diagnosis , Meningitis, Cryptococcal/drug therapy , Middle Aged , Patient Compliance , Retrospective Studies , Treatment Outcome
11.
Bone Joint J ; 98-B(2): 179-86, 2016 Feb.
Article in English | MEDLINE | ID: mdl-26850422

ABSTRACT

AIMS: There are many guidelines that help direct the management of patients with metal-on-metal (MOM) hip arthroplasties. We have undertaken a study to compare the management of patients with MOM hip arthroplasties in different countries. METHODS: Six international tertiary referral orthopaedic centres were invited to participate by organising a multi-disciplinary team (MDT) meeting, consisting of two or more revision hip arthroplasty surgeons and a musculoskeletal radiologist. A full clinical dataset including history, blood tests and imaging for ten patients was sent to each unit, for discussion and treatment planning. Differences in the interpretation of findings, management decisions and rationale for decisions were compared using quantitative and qualitative methods. RESULTS: Overall agreement between the orthopaedic centres and the recommended treatment plans for the ten patients with MOM hip implants was moderate (kappa = 0.6). Full agreement was seen in a third of cases, however split decisions were also seen in a third of cases. Units differed in their interpretation of the significance of the investigation findings and put varying emphasis on serial changes, in the presence of symptoms. DISCUSSION: In conclusion, the management of raised or rising blood metal ions, cystic pseudotumours and peri-acetabular osteolysis led to inconsistency in the agreement between centres. Coordinated international guidance and MDT panel discussions are recommended to improve consensus in decision making. TAKE HOME MESSAGE: A lack of evidence and the subsequent variation in regulator guidance leads to differences in opinions, the clinical impact of which can be reduced through a multi-disciplinary team approach to managing patients with MOM hip implants. Cite this article: Bone Joint J 2016;98-B:179-86.


Subject(s)
Arthroplasty, Replacement, Hip/instrumentation , Hip Prosthesis , Metal-on-Metal Joint Prostheses , Academic Medical Centers , Aged , Arthroplasty, Replacement, Hip/methods , Biomarkers/metabolism , Female , Granuloma, Plasma Cell/therapy , Humans , Interprofessional Relations , Ions/metabolism , Male , Metals/metabolism , Middle Aged , Observer Variation , Osteolysis/therapy , Patient Care Team , Postoperative Complications/therapy , Range of Motion, Articular/physiology , Reoperation
12.
Br J Anaesth ; 115(2): 285-93, 2015 Aug.
Article in English | MEDLINE | ID: mdl-26170351

ABSTRACT

BACKGROUND: Pregabalin may reduce postoperative pain and opioid use. Higher doses may be more effective, but may cause sedation and confusion. This prospective, randomized, blinded, placebo-controlled study tested the hypothesis that pregabalin reduces pain at 2 weeks after total knee arthroplasty, but increases drowsiness and confusion. METHODS: Patients (30 per group) received capsules containing pregabalin (0, 50, 100, or 150 mg); two capsules before surgery, one capsule twice a day until postoperative day (POD) 14, one on POD15, and one on POD16. Multimodal analgesia included femoral nerve block, epidural analgesia, oxycodone-paracetamol, and meloxicam. The primary outcome was pain with flexion (POD14). RESULTS: Pregabalin did not reduce pain at rest, with ambulation, or with flexion at 2 weeks (P=0.69, 0.23, and 0.90, respectively). Pregabalin increased POD1 drowsiness (34.5, 37.9, 55.2, and 58.6% in the 0, 50, 100, and 150 mg arms, respectively; P=0.030), but did not increase confusion (0, 3.5, 0, and 3.5%, respectively; P=0.75). Pregabalin had no effect on acute or chronic pain, opioid consumption, or analgesic side-effects. Pregabalin reduced POD14 patient satisfaction [1-10 scale, median (first quartile, third quartile): 9 (8, 10), 8 (7, 10), 8 (5, 9), and 8 (6, 9.3), respectively; P=0.023). Protocol compliance was 63% by POD14 (50.0, 70.0, 76.7, and 56.7% compliance, respectively), with no effect of dose on compliance. Per-protocol analysis of compliant patients showed no effect of pregabalin on pain scores. CONCLUSIONS: Pregabalin had no beneficial effects, but increased sedation and decreased patient satisfaction. This study does not support routine perioperative pregabalin for total knee arthroplasty patients. CLINICAL TRIAL REGISTRATION: ClinicalTrials.gov: http://www.clinicaltrials.gov/ct2/show/study/NCT01333956.


Subject(s)
Analgesics/therapeutic use , Arthroplasty, Replacement, Knee , Pain, Postoperative/drug therapy , gamma-Aminobutyric Acid/analogs & derivatives , Adult , Aged , Dose-Response Relationship, Drug , Double-Blind Method , Female , Humans , Male , Middle Aged , Pregabalin , Prospective Studies , gamma-Aminobutyric Acid/adverse effects , gamma-Aminobutyric Acid/therapeutic use
13.
Article in English | MEDLINE | ID: mdl-26764684

ABSTRACT

We show the effects of simulated supersonic granular flow made up of smooth particles passing over two prototypical bodies: a wedge and a disk. We describe a way of computationally identifying shock wave locations in granular flows and tabulate the shock wave locations for flow over wedges and disks. We quantify the shock structure in terms of oblique shock angle for wedge impediments and shock standoff distance for disk impediments. We vary granular flow parameters including upstream volume fraction, average upstream velocity, granular temperature, and the collision coefficient of restitution. Both wedges and disks have been used in the aerospace community as prototypical impediments to flowing air in order to investigate the fundamentally different shock structures emanating from sharp and blunt bodies, and we present these results in order to increase the understanding of the fundamental behavior of supersonic granular flow.

14.
Bone Joint J ; 95-B(5): 629-35, 2013 May.
Article in English | MEDLINE | ID: mdl-23632672

ABSTRACT

In a randomised controlled pragmatic trial we investigated whether local infiltration analgesia would result in earlier readiness for discharge from hospital after total knee replacement (TKR) than patient-controlled epidural analgesia (PCEA) plus femoral nerve block. A total of 45 patients with a mean age of 65 years (49 to 81) received a local infiltration with a peri-articular injection of bupivacaine, morphine and methylprednisolone, as well as adjuvant analgesics. In 45 PCEA+femoral nerve blockade patients with a mean age of 67 years (50 to 84), analgesia included a bupivacaine nerve block, bupivacaine/hydromorphone PCEA, and adjuvant analgesics. The mean time until ready for discharge was 3.2 days (1 to 14) in the local infiltration group and 3.2 days (1.8 to 7.0) in the PCEA+femoral nerve blockade group. The mean pain scores for patients receiving local infiltration were higher when walking (p = 0.0084), but there were no statistically significant differences at rest. The mean opioid consumption was higher in those receiving local infiltration. The choice between these two analgesic pathways should not be made on the basis of time to discharge after surgery. Most secondary outcomes were similar, but PCEA+femoral nerve blockade patients had lower pain scores when walking and during continuous passive movement. If PCEA+femoral nerve blockade is not readily available, local infiltration provides similar length of stay and similar pain scores at rest following TKR.


Subject(s)
Analgesia, Epidural , Anesthetics, Local/therapeutic use , Arthroplasty, Replacement, Knee , Nerve Block , Pain, Postoperative/drug therapy , Aged , Aged, 80 and over , Female , Humans , Male , Middle Aged , Prospective Studies
15.
Orthop Traumatol Surg Res ; 98(3): 281-7, 2012 May.
Article in English | MEDLINE | ID: mdl-22459099

ABSTRACT

INTRODUCTION: Ceramic-on-ceramic total hip arthroplasty is routinely used for young and active patients with end stage of hip osteoarthritis. However, squeaking noise is a recently identified problem with such bearing surface. Many in vivo and in vitro studies have been conducted trying to find the potential causes of this phenomenon. However, we are not aware of any study analyzing retrieved ceramic implants for squeaking. HYPOTHESIS: Our primary hypothesis was that the surface analysis of retrieved ceramic implants with squeaking would present interesting deteriorations that could explain the squeaking noise. MATERIALS AND METHODS: Nine retrieved squeaking implants from ceramic-on-ceramic total hip arthroplasty that were retrieved for various reasons (two exclusively for squeaking, four for recurrent dislocation, one for aseptic loosening and two for instability) were analyzed. Implant positioning was calculated, macroscopic damages were noticed and microscopic roughness was analyzed. The retrieved implants were then tested on a hip simulator reproducing flexion/extension motions in several situations in lubricated and non-lubricated conditions in order to reproduce squeaking. RESULTS: Five cups were considered with borderline insufficient anteversion. Gross impingement damage was visible on seven implants. All the retrieved heads had visible metal transfer on their surface. Eight implants had visible stripe wear. Microscopic analysis showed roughness higher than six microns on the retrieved heads. Squeaking was reproduced in vitro in dry conditions. In lubricated conditions, squeaking did not occur for the retrieved hips. DISCUSSION: This retrieval analysis suggests that problems of cup orientation and design which can lead to impingement can generate lubrication problems because of metal transfer plus/minus stripe wear which is a common theme in ceramic-on-ceramic bearings that squeak.


Subject(s)
Aluminum Oxide/chemistry , Ceramics/chemistry , Hip Prosthesis , Materials Testing/methods , Stress, Mechanical , Adult , Aged , Arthroplasty, Replacement, Hip , Equipment Failure Analysis , Female , Humans , Lubricants/chemistry , Lubrication , Male , Middle Aged , Osteoarthritis, Hip/surgery , Prosthesis Design , Prosthesis Failure , Surface Properties
16.
Brain Behav Immun ; 24(2): 273-80, 2010 Feb.
Article in English | MEDLINE | ID: mdl-19822203

ABSTRACT

Three to 5 days after a primary HSV-1 infection, macrophages infiltrate into the trigeminal ganglia (TG) and produce anti-viral cytokines to reduce viral replication. Previous research demonstrated that social disruption stress (SDR) enhances the trafficking of monocytes/macrophages from the bone marrow to the spleen and increases pro-inflammatory cytokine production in vitro and in vivo. The impact of SDR on the trafficking of these cells to loci of herpes simplex virus type 1 (HSV-1) infection and subsequent function has not been examined. The following studies were designed to determine whether SDR would enhance the innate immune response during a primary HSV-1 infection by increasing the number of macrophages in the cornea and TG, thus increasing anti-viral cytokine production and reducing viral replication. BALB/c mice were exposed to six cycles of SDR prior to ocular infection with HSV-1 McKrae virus. Flow cytometric analysis of cells from the TG revealed an increase in the percentage of CD11b+ macrophages in SDR mice compared to controls. Immune cell infiltration into the cornea, however, could not be determined due to low cell numbers. Although gene expression of IFN-beta was decreased, SDR increased gene expression of IFN-alpha, and TNF-alpha, in the cornea and TG. Examination of viral proteins showed decreased expression of infected cell protein 0 (ICP0), glycoprotein B (gB), glycoprotein H (gH) and latency-associated transcript (LAT) in the TG, however, expression of ICP0 and gB were elevated in the cornea of SDR mice. These results indicate that the innate immune response to HSV-1 was altered and enhanced by the experience of repeated social defeat.


Subject(s)
Cornea/immunology , Cornea/virology , Herpes Simplex/immunology , Herpes Simplex/psychology , Herpesvirus 1, Human , Immunity, Innate/physiology , Social Environment , Stress, Psychological/immunology , Trigeminal Ganglion/immunology , Trigeminal Ganglion/virology , Animals , CD11b Antigen/metabolism , Cornea/metabolism , Cytokines/biosynthesis , Flow Cytometry , Gene Expression/physiology , Herpes Simplex/virology , Macrophages/metabolism , Macrophages/physiology , Male , Mice , Mice, Inbred BALB C , RNA/biosynthesis , RNA/isolation & purification , Reverse Transcriptase Polymerase Chain Reaction , Trigeminal Ganglion/metabolism , Viral Proteins/biosynthesis , Viral Proteins/genetics
17.
Brain Behav Immun ; 23(2): 225-31, 2009 Feb.
Article in English | MEDLINE | ID: mdl-18848983

ABSTRACT

Stress hormones significantly impact dendritic cell (DC) activation and function, typically in a suppressive fashion. However, a social stressor termed social disruption (SDR) has been shown to induce an increase in inflammatory responses and a state of glucocorticoid resistance in splenic CD11b+ monocytes. These experiments were designed to determine the effects of SDR on DC activation, Toll-like receptor-induced cytokine secretion, and glucocorticoid sensitivity. Compared to cells obtained from control animals, splenic DCs from SDR mice displayed increased levels of MHC I, CD80, and CD44, indicative of an activated phenotype. In addition, DCs from SDR mice produced comparatively higher TNF-alpha, IL-6, and IL-10 in response to in vitro stimulation with LPS and CpG DNA. Increased amounts of TNF-alpha and IL-6 were also evident in SDR DC cultures stimulated with poly(I:C). Furthermore, as shown previously in CD11b+ monocytes, the CD11c+ DCs obtained from SDR mice were glucocorticoid resistant. Taken together, the data suggest that social stress, in the absence of any immune challenge, activates DCs, increases DC cytokine secretion in response to Toll-specific stimuli and renders DCs glucocorticoid resistant.


Subject(s)
Dendritic Cells/immunology , Dominance-Subordination , Glucocorticoids/metabolism , Spleen/cytology , Stress, Psychological/immunology , Toll-Like Receptors/metabolism , Analysis of Variance , Animals , B7-1 Antigen/metabolism , CD11b Antigen/metabolism , CD11c Antigen/metabolism , Cells, Cultured , Cytokines/metabolism , Flow Cytometry , Genes, MHC Class I/physiology , Glucocorticoids/pharmacology , Hyaluronan Receptors/metabolism , Interleukin-10/metabolism , Interleukin-6/metabolism , Lipopolysaccharides/toxicity , Male , Mice , Mice, Inbred C57BL , Monocytes/immunology , Monocytes/metabolism , Spleen/immunology , Tumor Necrosis Factor-alpha/metabolism
18.
Gait Posture ; 26(4): 489-93, 2007 Oct.
Article in English | MEDLINE | ID: mdl-17869114

ABSTRACT

BACKGROUND: Microprocessor-controlled knee joints appeared on the market a decade ago. These joints are more sophisticated and more expensive than mechanical ones. The literature is contradictory regarding changes in gait and balance when using these sophisticated devices. METHODS: This study employed a crossover design to assess the comparative performance of a passive mechanical knee prosthesis compared to a microprocessor-controlled knee joint in 15 subjects with an above-knee amputation. Objective measurements of gait and balance were obtained. RESULTS: Subjects demonstrated significantly improved gait characteristics after receiving the microprocessor-controlled prosthetic knee joint (p<0.01). Improvements in gait were a transition from a hyperextended knee to a flexed knee during loading response which resulted in a change from an internal knee flexor moment to a knee extensor moment. The participants' balance also improved (p<0.01). All conditions of the Sensory Organization Test (SOT) demonstrated improvements in equilibrium score. The composite score also increased. CONCLUSIONS: Transfemoral amputees using a microprocessor-controlled knee have significant improvements in gait and balance.


Subject(s)
Amputees/rehabilitation , Artificial Limbs , Gait/physiology , Knee Prosthesis , Microcomputers , Postural Balance , Activities of Daily Living , Adult , Analysis of Variance , Biomechanical Phenomena , Cross-Over Studies , Humans , Middle Aged , Prosthesis Design
19.
Mycologia ; 96(2): 205-7, 2004.
Article in English | MEDLINE | ID: mdl-21148845

ABSTRACT

Inadequate attention to zoosporangial discharge has led to confusion in watermold taxonomic literature. This problem is discussed in light of a specimen of Protoachlya hypogyna that manifests discharge characteristic of three watermold genera, and recommendations are made to reduce future inaccuracies.

20.
Women Health ; 33(3-4): 1-14, 2001.
Article in English | MEDLINE | ID: mdl-11527098

ABSTRACT

High false positive rates associated with screening for breast cancer in the United States have an unintended psychological consequence for women (Lerman et al., 1991) that has raised concerns in recent years (Sox, 1998). This study uses inductive qualitative analysis of open-ended interviews with 45 African American women living in New York City who were part of a larger study of women and their experiences after receiving an abnormal mammogram. Themes resulting from the analyses included: inadequate provider-patient communication, anxieties exacerbated by waiting and wondering, and fears of iatrogenic effects of follow-up tests such as biopsies and repeat mammograms. While more research is needed on message-framing strategies for women entering mammographic testing and follow-up, modest changes in service delivery such as improved medical communication can help to alleviate fears and enhance trust.


Subject(s)
Black or African American/psychology , Breast Neoplasms/diagnostic imaging , False Positive Reactions , Mammography/psychology , Patient Acceptance of Health Care/psychology , Adult , Aged , Anxiety , Breast Neoplasms/psychology , Communication , Fear , Female , Humans , Interviews as Topic , Mammography/statistics & numerical data , Middle Aged , New York City , Patient Acceptance of Health Care/ethnology , Physician-Patient Relations , Truth Disclosure
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