scholarly journals Wear performance of retrieved metal-on-metal Pinnacle hip arthroplasties implanted before and after 2007

2018 ◽  
Vol 7 (11) ◽  
pp. 595-600 ◽  
Author(s):  
S. Bergiers ◽  
H. S. Hothi ◽  
J. Henckel ◽  
A. Eskelinen ◽  
J. Skinner ◽  
...  
Keyword(s):  
Linear Regression Models ◽  
Wear Performance ◽  
Wear Rates ◽  
Female Patients ◽  
High Profile ◽  
Metal On Metal ◽  
Significant Difference ◽  
Before And After ◽  
Hip Arthroplasties ◽  
Mean Time

ObjectivesPrevious studies have suggested that metal-on-metal (MoM) Pinnacle (DePuy Synthes, Warsaw, Indiana) hip arthroplasties implanted after 2006 exhibit higher failure rates. This was attributed to the production of implants with reduced diametrical clearances between their bearing surfaces, which, it was speculated, were outside manufacturing tolerances. This study aimed to better understand the performance of Pinnacle Systems manufactured before and after this event.MethodsA total of 92 retrieved MoM Pinnacle hips were analyzed, of which 45 were implanted before 2007, and 47 from 2007 onwards. The ‘pre-2007’ group contained 45 implants retrieved from 21 male and 24 female patients, with a median age of 61.3 years (interquartile range (IQR) 57.1 to 65.5); the ‘2007 onwards’ group contained 47 implants retrieved from 19 male and 28 female patients, with a median age of 61.8 years (IQR 58.5 to 67.8). The volume of material lost from their bearing and taper surfaces was measured using coordinate and roundness measuring machines. These outcomes were then compared statistically using linear regression models, adjusting for potentially confounding factors.ResultsThere was no significant difference between the taper and bearing wear rates of the ‘pre-2007’ and ‘2007 onwards’ groups (p = 0.67 and p = 0.39, respectively). Pinnacles implanted from 2007 onwards were revised after a mean time of 50 months, which was significantly earlier than the ‘pre-2007’ hips (96 months) (p < 0.001). A reduction in the time to revision was present year on year from 2003 to 2011.ConclusionWe found no difference in the wear rate of these implants based on the year of implantation. The ‘pre-2007’ hips had a two-fold greater time to revision than those implanted after 2007; this may be due to the increased surveillance of MoM hips following UK regulatory advice and several high-profile failures. Interestingly, we observed a decreasing trend in the mean time to revision every year from 2003 onwards. Cite this article: S. Bergiers, H. S. Hothi, J. Henckel, A. Eskelinen, J. Skinner, A. Hart. Wear performance of retrieved metal-on-metal Pinnacle hip arthroplasties implanted before and after 2007. Bone Joint Res 2018;7:595–600. DOI: 10.1302/2046-3758.711.BJR-2018-0143.R1.

scholarly journals Does diametrical clearance influence the wear of Pinnacle hip implants?

2020 ◽  
Vol 9 (8) ◽  
pp. 515-523 ◽  
Author(s):  
Sean Bergiers ◽  
Harry Hothi ◽  
Johann Henckel ◽  
Antti Eskelinen ◽  
John Skinner ◽  
...  
Keyword(s):  
Volumetric Wear ◽  
Wear Performance ◽  
Wear Rates ◽  
Manufacturing Tolerance ◽  
Metal On Metal ◽  
Hip Arthroplasties ◽  
The Relationship ◽  
Spearman’S Correlation ◽  
Film Lubrication ◽  
Fluid Film Lubrication

Aims The optimum clearance between the bearing surfaces of hip arthroplasties is unknown. Theoretically, to minimize wear, it is understood that clearances must be low enough to maintain optimal contact pressure and fluid film lubrication, while being large enough to allow lubricant recovery and reduce contact patch size. This study aimed to identify the relationship between diametrical clearance and volumetric wear, through the analysis of retrieved components. Methods A total of 81 metal-on-metal Pinnacle hips paired with 12/14 stems were included in this study. Geometrical analysis was performed on each component, using coordinate and roundness measuring machines. The relationship between their as-manufactured diametrical clearance and volumetric wear was investigated. The Mann-Whitney U test and unpaired t-test were used, in addition to calculating the non-parametric Spearman's correlation coefficient, to statistically evaluate the acquired data. Results The hips in this study were found to have had a median unworn diametrical clearance of 90.31 μm (interquartile range (IQR) 77.59 to 97.40); 32% (n = 26) were found to have been below the manufacturing tolerance. There was no correlation found between clearance and bearing (rs = -0.0004, p = 0.997) or taper (rs = 0.0048, p = 0.966) wear rates. The wear performance of hips manufactured within and below these specifications was not significantly different (bearing: p = 0.395; taper: p = 0.653). Pinnacles manufactured from 2007 onwards had a greater prevalence of bearing clearance below tolerance (p = 0.004). Conclusion The diametrical clearance of Pinnacle hips did not influence their wear performance, even when below the manufacturing tolerance. The optimum clearance for minimizing hip implant wear remains unclear. Cite this article: Bone Joint Res 2020;9(8):515–523.

Clinical Wear Performance of Metal-on-Metal Hip Arthroplasties

2009 ◽  
pp. 144-144-13 ◽  
Author(s):  
CB Rieker ◽  
P Köttig ◽  
R Schön ◽  
M Windler ◽  
UP Wyss
Keyword(s):  
Wear Performance ◽  
Metal On Metal ◽  
Hip Arthroplasties

The wear of metal-on-metal total hip prostheses measured in a hip simulator

2001 ◽  
Vol 215 (6) ◽  
pp. 523-530 ◽  
Author(s):  
S C Scholes ◽  
S M Green ◽  
A Unsworth
Keyword(s):  
Steady State ◽  
Wear Test ◽  
Wear Testing ◽  
Radial Clearance ◽  
Hip Prostheses ◽  
Wear Rates ◽  
Joint Friction ◽  
Metal On Metal ◽  
Before And After ◽  
Friction Measurements

New generation metal-on-metal prostheses have been introduced to try and overcome the problem of osteolysis often attributed to the wear particles of the polyethylene component of conventional metal-on-ultra-high molecular weight polyethylene (UHMWPE) joints. The wear rates of four metal-on-metal joints (two different clearances) were assessed along with that of a conventional metal-on-UHMWPE joint. Friction measurements of the metal-on-metal joints were taken before and after the wear test and compared. Two distinct wear phases were discernible for all the metal-on-metal joints: an initial wear phase up to 0.5 × 106 cycles and then a lower steady state wear phase. The steady state wear rate of the 22 μUm radial clearance metal-on-metal joint was lower than that for the 40 μUm radial clearance joint, although this difference was not found to be significant ( p > 0.15). The wear rates for all the joints tested were consistent with other simulator studies. The friction factors produced by each joint were found to decrease significantly after wear testing ( p < 0.05).

scholarly journals Enlargement rate of geographic atrophy before and after secondary CNV conversion with associated anti-VEGF treatment

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Jakob Siedlecki ◽  
Caroline Koch ◽  
Benedikt Schworm ◽  
Raffael Liegl ◽  
Thomas Kreutzer ◽  
...  
Keyword(s):  
Growth Rate ◽  
Geographic Atrophy ◽  
Vascular Endothelial ◽  
Anti Vegf ◽  
Significant Difference ◽  
Before And After ◽  
Endothelial Growth Factor ◽  
Mean Time ◽  
Larger Sample

Abstract Background To study the enlargement rate of primary geographic atrophy (GA) before and after diagnosis of a secondary choroidal neovascularization (CNV) treated with anti-vascular endothelial growth factor (VEGF) therapy. Methods Five hundred twenty-two consecutive eyes with primary GA were screened for the development of a complicating secondary CNV. Geographic atrophy was measured on blue autofluorescence (BAF) by two readers and calculated into mean growth rate before and after CNV diagnosis. Results Ten eyes of six patients were included in the study (six study eyes with GA complicated by CNV, four GA only partner eyes). Follow-up was 1.42 ± 0.48 years before and 3.64 ± 2.73 years after CNV. There was no significant difference between mean growth rate before and after CNV (1.58 ± 0.99 vs. 1.39 ± 0.65 mm2/year; p = 0.44) or between study and partner eyes (p = 0.86). Over a mean time of 3.64 ± 2.73 years, a mean of 8.3 ± 2.8 anti-VEGF injections were given. No correlation between the amount of anti-VEGF injections and change in growth rate could be observed (r = 0.58; p = 0.23). Conclusion In this pilot study, primary GA enlargement did not seem to be influenced by a secondary CNV. No association between the intensity of anti-VEGF treatment and changes in atrophy enlargement rates were found. Further studies with larger sample sizes are warranted.

Abstract W P299: Impact of an Institutional Guideline on Implementing Early Decompressive Hemicraniectomy (DHC) for Large Middle Cerebral Artery Stroke

Stroke ◽  
2015 ◽  
Vol 46 (suppl_1) ◽  
Author(s):  
Casey Olm-Shipman ◽  
Victoria Marquevich ◽  
Jonathan Rosand ◽  
Aman Patel ◽  
Emad Eskandar ◽  
...  
Keyword(s):  
Clinical Trials ◽  
Guideline Implementation ◽  
Rapid Identification ◽  
Decompressive Hemicraniectomy ◽  
Significant Difference ◽  
Class 1 ◽  
Before And After ◽  
The Impact ◽  
Mean Time

Background: Recent AHA Acute Stroke Guidelines endorse DHC (Class 1, Level B) based on clinical trials showing benefit of early DHC on outcome and mortality. In 2011, our multidisciplinary quality improvement team developed a process to translate DHC guideline recommendations into clinical practice. Methods: Our consensus guideline includes a tool (STATE Criteria, based on inclusion/exclusion criteria of DHC clinical trials) to rapidly identify and triage potential DHC candidates, and provide specific guidelines for pre- and post-surgical management, adjunctive therapy, and DHC after IV/IA thrombolysis. Patients meeting all STATE Criteria including age ≤ 60 years are sent for urgent DHC. Patients meeting all criteria except age ≤ 60 years receive DHC only if age < 75 years and Neurology and Neurosurgery teams reach consensus about benefit. Patients not meeting criteria are observed and referred for DHC if criteria are met within 48 hours of onset. The guideline was disseminated to all stakeholders via email, conferences, and intranet. In this study, we retrospectively analyzed process and outcome measures for DHC before and after guideline implementation in February 2011. Results: Of 1518 stroke patients age ≤ 60 years admitted between January 2007 and April 2014, 47 (3%) received DHC (22 pre- and 25 post-guideline implementation; 28% female, 13% Hispanic). Mean admission NIHSS was similar (17±7 vs 18±5; p=.82). Mean time from admission to DHC improved significantly from 45±30 hours to 29±18 hours (p=0.04). The percentage of patients undergoing DHC beyond 48 hours decreased from 27% to 16% (p=0 .35). The degree of midline shift evident on CT or MRI prior to DHC significantly decreased from 9±4 mm to 5±4 mm (p=.01). There was no significant difference in length of stay, frequency of tracheostomy, gastrostomy, pneumonia, or urinary tract infection, or percentage of patients who died within 30 days of DHC. Conclusion: Our institutional guideline has facilitated the rapid identification and triage of patients with large MCA stroke to DHC. Follow-up is ongoing to determine the impact of our guideline on functional outcome after stroke.

Compliance in doing Senam Kesegaran Jasmani 1988 exercise improves cardiorespiratory endurance of attention deficit/hyperactivity disorder children

2018 ◽  
Vol 27 (1) ◽  
pp. 44-53
Author(s):  
Listya T. Mirtha ◽  
Rini Sekartini
Keyword(s):  
Attention Deficit Hyperactivity Disorder ◽  
Physical Exercise ◽  
Attention Deficit ◽  
Supportive Therapy ◽  
Endurance Test ◽  
Hyperactivity Disorder ◽  
Significant Difference ◽  
Before And After ◽  
Cardiorespiratory Endurance ◽  
Mean Time

Background: Physical exercise was hypothesized to be able to improve the behavior of children with attention deficit/hyperactivity disorder (ADHD) by improving attention and concentration. Several studies mentioned that physical exercise could make ADHD children calmer, not only as a supportive therapy, but also as a therapeutic therapy. The aim of this study was to evaluate the effects of physical exercise to the behavior of ADHD patients and to analyze the effects of Senam Kesegaran Jasmani 1988 (SKJ 88) exercise compliance to the cardiorespiratory endurance in ADHD children.Methods: This study was an experimental study with 40 subjects from a special needs school in Tangerang, Indonesia. Subjects were given SKJ 88 exercise for 8 weeks, and the level of cardiorespiratory endurance was assessed with 600 m run before and after intervention.Results: 21 subjects (52.5%) were compliant, and the rest were very compliant. Although statistical analysis showed that there was no significant difference in cardiorespiratory endurance before and after intervention, the mean results of cardiorespiratory endurance test before intervention was higher than after. Mean time spent in the 600-m run before intervention was 497.9 seconds (SD 73.53), and after intervention was 313.7 seconds (SD 43.28).Conclusion: Based on the statistical test, we concluded that there was significant decrease of time spent for cardiorespiratory endurance test (p<0.001). The reduction of time taken to run 600 m by 184.3 seconds (SD 73.33) showed the improvement of cardiorespiratory endurance after the treatment.

scholarly journals Aseptic lymphocyte-dominated vasculitis-associated lesions are related to changes in metal ion handling in the joint capsules of metal-on-metal hip arthroplasties

2018 ◽  
Vol 7 (6) ◽  
pp. 388-396 ◽  
Author(s):  
D. J. Langton ◽  
R. P. Sidaginamale ◽  
T. J. Joyce ◽  
J. G. Bowsher ◽  
J. P. Holland ◽  
...  
Keyword(s):  
Metal Ion ◽  
Fluid Collection ◽  
Joint Fluid ◽  
Volumetric Wear ◽  
Wear Rates ◽  
Ion Concentrations ◽  
Associated Lesions ◽  
Metal On Metal ◽  
Hip Arthroplasties ◽  
Co Concentrations

Objectives We have encountered patients who developed large joint fluid collections with massive elevations in chromium (Cr) and cobalt (Co) concentrations following metal-on-metal (MoM) hip arthroplasties. In some cases, retrieval analysis determined that these ion concentrations could not be explained simply by the wear rates of the components. We hypothesized that these effects may be associated with aseptic lymphocyte-dominated vasculitis-associated lesion (ALVAL). Patients and Methods We examined the influence of the ALVAL grade on synovial fluid Co and Cr concentrations following adjustment for patient and device variables, including volumetric wear rates. Initially restricting the analysis to include only patients with one MoM hip resurfacing device, we performed multiple regression analyses of prospectively collected data. We then repeated the same statistical approach using results from a larger cohort with different MoM designs, including total hip arthroplasties. Results In the resurfacing cohort (n = 76), the statistical modelling indicated that the presence of severe ALVAL and a large fluid collection were associated with greater joint fluid Co concentrations after adjustment for volumetric wear rates (p = 0.005). These findings were replicated in the mixed implant group (n = 178), where the presence of severe ALVAL and a large fluid collection were significantly associated with greater fluid Co concentrations (p < 0.001). Conclusion The development of severe ALVAL is associated with elevations in metal ion concentrations far beyond those expected from the volumetric loss from the prosthetic surfaces. This finding may aid the understanding of the sequence of events leading to soft-tissue reactions following MoM hip arthroplasties. Cite this article: D. J. Langton, R. P. Sidaginamale, T. J. Joyce, J. G. Bowsher, J. P. Holland, D. Deehan, A. V. F. Nargol, S. Natu. Aseptic lymphocyte-dominated vasculitis-associated lesions are related to changes in metal ion handling in the joint capsules of metal-on-metal hip arthroplasties. Bone Joint Res 2018;7:388–396. DOI: 10.1302/2046-3758.76.BJR-2018-0037.

scholarly journals The effect of hysteroscopic polypectomy on the concentrations of tumour necrosis factor-α in uterine flushings and serum in infertile women

2020 ◽  
Vol 148 (5-6) ◽  
pp. 315-321
Author(s):  
Ana Devic ◽  
Mladenko Vasiljevic ◽  
Marija Sorak ◽  
Aleksandar Devic ◽  
Ivana Rudic-Biljic-Erski ◽  
...  
Keyword(s):  
Venous Blood ◽  
Control Group ◽  
Endometrial Polyps ◽  
Infertile Women ◽  
Female Patients ◽  
Significant Difference ◽  
Before And After ◽  
Factor Α ◽  
Experimental Group ◽  
Necrosis Factor

Introduction/Objective. The aim of this paper is to present changes of tumor necrosis factor-? (TNF-?) levels in uterine flushings and serum of infertile female patients before and after hysteroscopic polypectomy. Methods. A total of 82 infertile female patients were included in the study. The patients were divided into two groups. The first group was the experimental group and comprised 56 infertile women with endometrial polyps, whereas the second group was the control group of 26 infertile women who were not diagnosed with endometrial polyps. Results. The results of this research primarily suggest that TNF-? concentrations obtained from uterine flushings and serum of infertile patients diagnosed with endometrial polyps differed before and after a surgical procedure. In the control group of patients, there was no significant difference observed regarding TNF-? concentrations in serum and uterine flushings of women without endometrial polyps. A comparison between these two groups revealed differences in TNF-? concentrations in both venous blood and uterine flushings. These differences were considered statistically significant. Conclusion. Endometrial polyps are one of the causes of higher TNF-? levels in both uterine flushings and serum.

A Step-System Treatment Milieu and Discharges from a Chronic Schizophrenic Ward

1976 ◽  
Vol 38 (1) ◽  
pp. 309-310
Author(s):  
Ronald L. Bergman
Keyword(s):  
Chronic Schizophrenic ◽  
Chronic Schizophrenics ◽  
Significant Difference ◽  
Before And After ◽  
Number Of Discharges ◽  
Mean Time ◽  
Higher Functioning

Discharges from a chronic schizophrenic ward were compared before and after the implementation of a step-system treatment format. The subjects were 80 chronic schizophrenics equally divided by sex with a mean age of 47.1 yr. and a mean time in hospital of 19.8 yr. While the step-system format yielded no significant difference in the total number of discharges, a significantly ( p < .05) greater number of higher functioning patients were discharged while it was in effect

scholarly journals Lip Morphological Changes and Differences before and after Orthodontic Treatment

2013 ◽  
Vol 1 (1) ◽  
pp. 5-12
Author(s):  
MR Islam ◽  
T Kitahara ◽  
L Naher ◽  
A Nakasima ◽  
I Takahashi
Keyword(s):  
Adult Female ◽  
Orthodontic Treatment ◽  
Morphological Changes ◽  
Class Ii ◽  
Class Iii ◽  
Class Iii Malocclusion ◽  
Skeletal Class ◽  
Female Patients ◽  
Significant Difference ◽  
Before And After

Objectives: The objective of this study is to test the hypothesis that there is a difference in the morphology of the lips of Class II div 1 and Class III malocclusion, before and after orthodontic treatment. Methods: The sample subjects included 20 adult female patients with Angle Class II div 1 malocclusion and 30 adult female patients with dento-skeletal Class III malocclusion. Frontal photographs were taken both before and after orthodontic and/or orthognathic treatment. Thirty-five landmarks were placed on each tracing made from the photograph. Thereafter, landmarks were digitized into an x and y coordinates system with the subnasal point as the origin. The Class II pretreatment and posttreatment groups of rest and smile conditions were compared with the Class III group respectively, using t-tests. Results: In the Class II pretreatment group, upper and lower lips positioned downward than that in the Class III group. When smiling, there was no statistically significant difference between the two groups before treatment, whereas after orthodontic treatment both Class II and Class III groups showed the significant difference at rest and on smiling conditions. On smiling condition Class III group showed more upwards and lateral movement of the mouth corners than Class II group. Conclusion: Orthodontic treatment induced larger amount in movement of lips at smiling in both Class II and III patients, which may reflect the emotional changes in the patients after treatment. DOI: http://dx.doi.org/10.3329/bjodfo.v1i1.15971 Ban J Orthod & Dentofac Orthop, October 2010; Vol-1, No.1, 5-12

Sign in / Sign up

Export Citation Format

Share Document