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Sample records for large-head metal-on-metal total

  1. Early failures in large head metal-on-metal total hip arthroplasty.

    PubMed

    Althuizen, Martje N R; V Hooff, Miranda L; v d Berg-v Erp, Saskia H M; V Limbeek, Jacques; Nijhof, Marc W

    2012-01-01

    Concerns have recently been raised about large head metal-on-metal total hip arthroplasties (LDH THA). Metal ion release due to wear may cause osteolysis, pseudotumours and necrosis. In addition, fixation of certain acetabular components is thought to be suboptimal. We present the short term outcome of the Durom LDH THA. Retrospectively, a consecutive series of 64 implants in 60 patients was analysed with a mean follow-up of 37 months. Clinical and radiological evaluation was performed on a regular basis, followed by additional evaluations when indicated. The 10-year revision percentage was calculated and compared with National Institute for Health and Clinical Excellence (NICE) standards. Six patients (six hips) underwent cup revision (9%). Four of these cups showed no or minimal bone fixation. Three patients had a pseudotumour. In two revision cases, ALVAL (aseptic lymphocyte-dominated vasculitis-associated lesion) was present. Lack of bone ingrowth and the presence of ARMD (adverse reaction to metal debris) seem to contribute to a high failure rate of the Durom LDH THA. The predicted ten-year revision rate of 14.2% (95% CI 5.6-22.8) is, given the broad confidence interval, not significantly outside NICE recommended standards. However, it is not clear which factors, if any, predict implant failure. Therefore, we do not advocate the use of this implant. PMID:23233178

  2. Large-head metal-on-metal total hip arthroplasty using the Durom acetabular component at minimum 1-year interval.

    PubMed

    Illgen, Richard L; Heiner, John P; Squire, Matthew W; Conrad, David N

    2010-09-01

    Large-head metal-on-metal total hip arthroplasty represents novel technology, and outcome data are lacking. We prospectively compared the performance of a nonmodular metal-on-metal acetabular component (Durom; Zimmer, Warsaw, IN) with a modular titanium component (Trilogy, Zimmer). All Durom components placed at our institution with minimum 1-year follow up (n = 63) were compared with an age- and sex-matched Trilogy control group (n = 100). Failure defined as revision or persistent moderate/severe groin pain was significantly higher for the Durom (11.1%) compared with the Trilogy group (0%) (P = .002). Although all acetabular components in both groups appeared radiographically stable, no significant bone ingrowth was noted at the time of Durom revisions. We could not identify any patient/surgical-related factors predictive of failure. Further study is needed to determine the scientific basis for these observations. PMID:20570096

  3. No association between serum metal ions and implant fixation in large-head metal-on-metal total hip arthroplasty

    PubMed Central

    Søballe, Kjeld; Jakobsen, Stig Storgaard; Lorenzen, Nina Dyrberg; Mechlenburg, Inger; Stilling, Maiken

    2014-01-01

    Background The mechanism of failure of metal-on-metal (MoM) total hip arthroplasty (THA) has been related to a high rate of metal wear debris, which is partly generated from the head-trunnion interface. However, it is not known whether implant fixation is affected by metal wear debris. Patients and methods 49 cases of MoM THA in 41 patients (10 women) with a mean age of 52 (28–68) years were followed with stereoradiographs after surgery and at 1, 2, and 5 years to analyze implant migration by radiostereometric analysis (RSA). Patients also participated in a 5- to 7-year follow-up with measurement of serum metal ions, questionnaires (Oxford hip score (OHS) and Harris hip score (HHS)), and measurement of cup and stem positions and systemic bone mineral density. Results At 1–2 years, mean total translation (TT) was 0.04 mm (95% CI: –0.07 to 0.14; p = 0.5) for the stems; at 2–5 years, mean TT was 0.13 mm (95% CI: –0.25 to –0.01; p = 0.03), but within the precision limit of the method. For the cups, there was no statistically significant TT or total rotation (TR) at 1–2 and 2–5 years. At 2–5 years, we found 4 cups and 5 stems with TT migrations exceeding the precision limit of the method. There was an association between cup migration and total OHS < 40 (4 patients, 4 hips; p = 0.04), but there were no statistically significant associations between cup or stem migration and T-scores < –1 (n = 10), cup and stem positions, or elevated serum metal ion levels (> 7µg/L (4 patients, 6 hips)). Interpretation Most cups and stems were well-fixed at 1–5 years. However, at 2–5 years, 4 cups and 5 stems had TT migrations above the precision limits, but these patients had serum metal ion levels similar to those of patients without measurable migrations, and they were pain-free. Patients with serum metal ion levels > 7 µg/L had migrations similar to those in patients with serum metal ion levels < 7 µg/L. Metal wear debris does not appear to influence the fixation of hip components in large-head MoM articulations at medium-term follow-up. PMID:24847790

  4. Does bearing size influence metal ion levels in large-head metal-on-metal total hip arthroplasty? A comparison of three total hip systems

    PubMed Central

    2014-01-01

    Background The purpose of the study was twofold: first, to determine whether there is a statistically significant difference in the metal ion levels among three different large-head metal-on-metal (MOM) total hip systems. The second objective was to assess whether position of the implanted prostheses, patient demographics or factors such as activity levels influence overall blood metal ion levels and whether there is a difference in the functional outcomes between the systems. Methods In a cross-sectional cohort study, three different metal-on-metal total hip systems were assessed: two monoblock heads, the Durom socket (Zimmer, Warsaw, IN, USA) and the Birmingham socket (Smith and Nephew, Memphis, TN, USA), and one modular metal-on-metal total hip system (Pinnacle, Depuy Orthopedics, Warsaw, IN, USA). Fifty-four patients were recruited, with a mean age of 59.7years and a mean follow-up time of 41months (12 to 60). Patients were evaluated clinically, radiologically and biochemically. Statistical analysis was performed on all collected data to assess any differences between the three groups in terms of overall blood metal ion levels and also to identify whether there was any other factor within the group demographics and outcomes that could influence the mean levels of Co and Cr. Results Although the functional outcome scores were similar in all three groups, the blood metal ion levels in the larger monoblock large heads (Durom, Birmingham sockets) were significantly raised compared with those of the Pinnacle group. In addition, the metal ion levels were not found to have a statistically significant relationship to the anteversion or abduction angles as measured on the radiographs. Conclusions When considering a MOM THR, the use of a monoblock large-head system leads to higher elevations in whole blood metal ions and offers no advantage over a smaller head modular system. PMID:24472283

  5. Pseudotumour incidence, cobalt levels and clinical outcome after large head metal-on-metal and conventional metal-on-polyethylene total hip arthroplasty: mid-term results of a randomised controlled trial.

    PubMed

    van der Veen, H C; Reininga, I H F; Zijlstra, W P; Boomsma, M F; Bulstra, S K; van Raay, J J A M

    2015-11-01

    We compared the incidence of pseudotumours after large head metal-on-metal (MoM) total hip arthroplasty (THA) with that after conventional metal-on-polyethylene (MoP) THA and assessed the predisposing factors to pseudotumour formation. From a previous randomised controlled trial which compared large head (38 mm to 60 mm) cementless MoM THA with conventional head (28 mm) cementless MoP THA, 93 patients (96 THAs: 41 MoM (21 males, 20 females, mean age of 64 years, standard deviation (sd) 4) and 55 MoP (25 males, 30 females, mean age of 65 years, sd 5) were recruited after a mean follow-up of 50 months (36 to 64). The incidence of pseudotumours, measured using a standardised CT protocol was 22 (53.7%) after MoM THA and 12 (21.8%) after MoP THA. Women with a MoM THA were more likely to develop a pseudotumour than those with a MoP THA (15 vs 7, odds ratio (OR) = 13.4, p < 0.001). There was a similar incidence of pseudotumours in men with MoM THAs and those with MoP THAs (7 vs 5, OR = 2.1, p = 0.30). Elevated cobalt levels (? 5 microgram/L) were only associated with pseudotumours in women with a MoM THA. There was no difference in mean Oxford and Harris hip scores between patients with a pseudotumour and those without. Contrary to popular belief, pseudotumours occur frequently around MoP THAs. Women with a MoM THA and an elevated cobalt level are at greatest risk. In this study, pseudotumours had no effect on the functional outcome after either large head MoM or conventional MoP THA. PMID:26530649

  6. Shorter, rough trunnion surfaces are associated with higher taper wear rates than longer, smooth trunnion surfaces in a contemporary large head metal-on-metal total hip arthroplasty system.

    PubMed

    Brock, Timothy M; Sidaginamale, Raghavendra; Rushton, Steven; Nargol, Antoni V F; Bowsher, John G; Savisaar, Christina; Joyce, Tom J; Deehan, David J; Lord, James K; Langton, David J

    2015-12-01

    Taper wear at the head-neck junction is a possible cause of early failure in large head metal-on-metal (LH-MoM) hip replacements. We hypothesized that: (i) taper wear may be more pronounced in certain product designs; and (ii) an increased abductor moment arm may be protective. The tapers of 104 explanted LH-MoM hip replacements revised for adverse reaction to metal debris (ARMD) from a single manufacturer were analyzed for linear and volumetric wear using a co-ordinate measuring machine. The mated stem was a shorter 12/14, threaded trunnion (n=72) or a longer, smooth 11/13 trunnion (n=32). The abductor moment arm was calculated from pre-revision radiographs. Independent predictors of linear and volumetric wear included taper angle, stem type, and the horizontal moment arm. Tapers mated with the threaded 12/14 trunnion had significantly higher rates of volumetric wear (0.402?mm3/yr vs. 0.123?mm3/yr [t=-2.145, p=0.035]). There was a trend to larger abductor moment arms being protective (p=0.055). Design variation appears to play an important role in taper-trunnion junction failure. We recommend that surgeons bear these findings in mind when considering the use of a short, threaded trunnion with a cobalt-chromium head. PMID:26135357

  7. Functional outcome following a large head total hip arthroplasty: A retrospective analysis of mid term results

    PubMed Central

    Agarwala, Sanjay; Mohrir, Ganesh; Moonot, Pradeep

    2014-01-01

    Background: One of the reasons that hip resurfacing and large head metal on metal (MOM) total hip arthroplasty (THA) became popular in Asia was the possible increased range of movement and thereby improved function of the hip joint. Due to concerns of MOM articulation an alternative bearing was sought. Hence, a shift from large head MOM to large head ceramic on ceramic (COC) was made. The aim of this study was to compare the functional outcome including range of motion (ROM) and dislocation rates following large head MOM and large head COC THA. Materials and Methods: Retrospectively, 39 primary THA with large head MOM with a mean age of 56 years (range 36-72 years) and average followup of 54 months (range 38-70 months) were compared with 23 primary THA with large head COC bearing with a mean age of 48 years (range 36-68 years) and an average followup of 18 months (range 12-26 months). Functional outcome was assessed using the Modified Harris Hip Score. Dislocation rate and ROM were compared. Results: Global ROM averaged 248 degrees with MOM group and 252 degrees with the COC group. One patient with metal bearing had dislocation at an average 3 year followup which required revision THA while there were no complications in the COC group. MHHS averaged 89 points in MOM and 94 in COC THR. Conclusion: This study has shown that large head ceramic on ceramic THA is a good alternative to large head metal on metal THA with comparable dislocation rates and range of movements and without complications of metallosis in Asian patients. PMID:25143647

  8. Metal-on-metal total hip arthroplasty: is there still a role in 2016?

    PubMed

    Silverman, Edward J; Ashley, Blair; Sheth, Neil P

    2016-03-01

    The use of metal-on-metal (MoM) bearings in total hip arthroplasty (THA) was popularized due to its enhanced wear profile and the ability to use large femoral heads to reduce post-operative instability. However, enthusiasm for the bearing declined following serious complications encountered at the primary articulation. This review discusses the development of MoM and the subsequent unexpected downstream challenges, most notably elevated serum metal ion levels, aseptic lymphocyte-dominated vasculitis-associated lesions (ALVAL), pseudotumor formation, and subsequent soft tissue and bone destruction. Both patient centered risk factors as well as component design led to high early failure rates resulting in product recalls and an overall decline in the use of MoM. In 2016, there is not a role for large-head MoM bearing in THA. Alternatively, the bearing has shown promise in hip resurfacing procedures for carefully selected patients. PMID:26791173

  9. Metal-on-Metal Total Hip Resurfacing Arthroplasty

    PubMed Central

    2006-01-01

    Executive Summary Objective The objective of this review was to assess the safety and effectiveness of metal on metal (MOM) hip resurfacing arthroplasty for young patients compared with that of total hip replacement (THR) in the same population. Clinical Need Total hip replacement has proved to be very effective for late middle-aged and elderly patients with severe degenerative diseases of the hips. As indications for THR began to include younger patients and those with a more active life style, the longevity of the implant became a concern. Evidence suggests that these patients experience relatively higher rates of early implant failure and the need for revision. The Swedish hip registry, for example, has demonstrated a survival rate in excess of 80% at 20 years for those aged over 65 years, whereas this figure was 33% by 16 years in those aged under 55 years. Hip resurfacing arthroplasty is a bone-conserving alternative to THR that restores normal joint biomechanics and load transfer. The technique has been used around the world for more than 10 years, specifically in the United Kingdom and other European countries. The Technology Metal-on-metal hip resurfacing arthroplasty is an alternative procedure to conventional THR in younger patients. Hip resurfacing arthroplasty is less invasive than THR and addresses the problem of preserving femoral bone stock at the initial operation. This means that future hip revisions are possible with THR if the initial MOM arthroplasty becomes less effective with time in these younger patients. The procedure involves the removal and replacement of the surface of the femoral head with a hollow metal hemisphere, which fits into a metal acetabular cup. Hip resurfacing arthroplasty is a technically more demanding procedure than is conventional THR. In hip resurfacing, the femoral head is retained, which makes it much more difficult to access the acetabular cup. However, hip resurfacing arthroplasty has several advantages over a conventional THR with a small (28 mm) ball. First, the large femoral head reduces the chance of dislocation, so that rates of dislocation are less than those with conventional THR. Second, the range of motion with hip resurfacing arthroplasty is higher than that achieved with conventional THR. A variety of MOM hip resurfacing implants are used in clinical practice. Six MOM hip resurfacing implants have been issued licences in Canada. Review Strategy A search of electronic bibliographies (OVID Medline, Medline In-Process and Other Non-Indexed Citations, Embase, Cochrane CENTRAL and DSR, INAHTA) was undertaken to identify evidence published from Jan 1, 1997 to October 27, 2005. The search was limited to English-language articles and human studies. The literature search yielded 245 citations. Of these, 11 met inclusion criteria (9 for effectiveness, 2 for safety). The result of the only reported randomized controlled trial on MOM hip resurfacing arthroplasty could not be included in this assessment, because it used a cemented acetabular component, whereas in the new generation of implants, a cementless acetabular component is used. After omitting this publication, only case series remained. Summary of Findings Health Outcomes The Harris hip score and SF-12 are 2 measures commonly used to report health outcomes in MOM hip resurfacing arthroplasty studies. Other scales used are the Oxford hip score and the University of California Los Angeles hip score. The case series showed that the mean revision rate of MOM hip resurfacing arthroplasty is 1.5% and the incidence of femoral neck fracture is 0.67%. Across all studies, 2 cases of osteonecrosis were reported. Four studies reported improvement in Harris hip scores. However, only 1 study reported a statistically significant improvement. Three studies reported improvement in SF-12 scores, of which 2 reported a significant improvement. One study reported significant improvement in UCLA hip score. Two studies reported postoperative Oxford hip scores, but no preoperative values were reported. None of the reviewed studies r

  10. Complications Related to Metal-on-Metal Articulation in Trapeziometacarpal Joint Total Joint Arthroplasty

    PubMed Central

    Frlich, Christina; Hansen, Torben Bk

    2015-01-01

    Adverse reactions to metal-on-metal (MoM) prostheses are well known from total hip joint resurfacing arthroplasty with elevated serum chrome or cobalt, pain and pseudo tumor formation. It may, however, also be seen after total joint replacement of the trapeziometacarpal joint using MoM articulation, and we present two cases of failure of MoM prostheses due to elevated metal-serum levels in one case and pseudo tumor formation in another case. Furthermore, we suggest a diagnostic algorithm for joint pain after MoM trapeziometacarpal joint replacement based on published experiences from MoM hip prostheses and adverse reactions to metal. PMID:26020592

  11. Complications Related to Metal-on-Metal Articulation in Trapeziometacarpal Joint Total Joint Arthroplasty.

    PubMed

    Frlich, Christina; Hansen, Torben Bk

    2015-01-01

    Adverse reactions to metal-on-metal (MoM) prostheses are well known from total hip joint resurfacing arthroplasty with elevated serum chrome or cobalt, pain and pseudo tumor formation. It may, however, also be seen after total joint replacement of the trapeziometacarpal joint using MoM articulation, and we present two cases of failure of MoM prostheses due to elevated metal-serum levels in one case and pseudo tumor formation in another case. Furthermore, we suggest a diagnostic algorithm for joint pain after MoM trapeziometacarpal joint replacement based on published experiences from MoM hip prostheses and adverse reactions to metal. PMID:26020592

  12. Crowe Type I and II DDH managed by large diameter metal-on-metal total hip arthroplasty.

    PubMed

    Yalcin, Nadir; Kilicarslan, Kasim; Cicek, Hakan; Kayaalp, Cetin; Yildirim, Hasan

    2011-01-01

    Large bearing metal-on-metal (MOM) total hip arthroplasty (THA) may offer advantages relating to stability and range of motion in patients with Crowe Type I and II developmental dysplasia of the hip (DDH). The purpose of this study was to provide an analysis of the clinical and radiological results of MOM THA in this context and compare the results with a cohort of patients treated with metal-on-polyethylene (MOP) bearing surfaces. 75 hips in 65 patients were treated with cementless MOM THA using large femoral heads (36-56 mm). The mean age of the patients was 47.4 years (29 to 59) and 54 were female. A group of 47 hips (41 patients) treated with conventional THA (screwed cup-polyethylene insert-28 mm head) was used for comparison. The study group was followed up for a mean of 62.1 months (32 to 76). No difference was found between the two groups in relation to improvement in Harris hip score (HHS) (43.1 to 90.3 points in the study group, 42.6 to 89.5 points in the control group, p>0.05). Although the preoperative range of motion in all planes were similar in both groups, the large head group demonstrated greater motion in all planes postoperatively, which was significant (all p=0.001). Additionally, there was a significant difference between groups in relation to the necessity for acetabular structural graft (8% and 31.9%, respectively; p=0.001). No major complications or adverse reactions to metal debris (ARMD) were observed in the study group. The results of large head MOM THA in young and active patients with DDH are similar to conventional THA at early follow-up, but the former offers the advantages of secure acetabular fixation without screws, greater range of motion, and lower risk of dislocation. PMID:21484734

  13. Metal-on-Metal Total Hip Arthroplasty: Patient Evaluation and Treatment.

    PubMed

    Bolognesi, Michael P; Ledford, Cameron K

    2015-12-01

    Metal-on-metal (MoM) hip articulations were thought to represent a biologic and biomechanically favorable alternative to conventional metal-on-polyethylene total hip arthroplasty implants. However, concerns emerged when registry data reported significantly higher failure rates associated with MoM implants compared with other contemporary hip implants. These high implant failure rates have been attributed to the release of metal particles into the periprosthetic space, creating macroscopic necrosis; corrosive osteolysis; large, sterile hip effusions; and periprosthetic solid and cystic masses (ie, pseudotumors)-a spectrum of findings termed adverse reaction to metal debris. A thorough clinical history and physical examination, along with laboratory data and imaging surveillance of these patients, is critical for appropriate diagnosis and treatment. The decision to perform revision hip arthroplasty of a metal-on-metal implant is multifactorial and should be based on documented, objective clinical indications. A systematic and objective approach to this evaluation and treatment is essential to optimize the care of patients who undergo total hip arthroplasty with MoM implants. PMID:26493972

  14. A finite element method comparison of wear in two metal-on-metal total hip prostheses.

    PubMed

    Cosmi, F; Hoglievina, M; Fancellu, G; Martinelli, B

    2006-11-01

    The contact mechanics of two metal-on-metal (MOM) total hip prostheses was studied by means of the finite element method (FEM). The purpose of the work was to compare two total hip replacements (Durom and Metasul) with regard to the amount of wear debris released. Wear on the bearing surfaces was evaluated following Reye hypotheses from the pressure distribution, computed by means of three-dimensional FEM models; an approximate analytical model based on Hertz contact theory has also been developed and discussed. The results show that in the dry friction condition the Durom joint releases almost twice as much wear volume as produced by the Metasul joint. Therefore, while Durom implants can improve hip stability by increasing the prosthetic impingement-free range of motion (PIF-ROM), Metasul prostheses can be a valuable solution whenever wear represents a critical choice factor. PMID:17236520

  15. Large diameter metal on metal total hip replacement for femoral neck fractures with neurological conditions

    PubMed Central

    Li, Jia; Zheng, Wei; Zhao, Jinzhu; Liu, Denghui; Xu, Weidong

    2014-01-01

    Background: Patients with Parkinson's disease and poliomyelitis can have a femoral neck fracture; yet, the optimal methods of treatment for these hips remains controversial. Many constrained or semi-constrained prostheses, using constrained liners (CLs) with a locking mechanism to capture the femoral head, were used to treat femoral neck fractures in patients with neurological disorders. We retrospectively studied a group of patients with Parkinson's disease and poliomyelitis who sustained femoral neck fractures and were treated by total hip arthroplasty using an L-MoM prosthesis. Materials and Methods: We retrospectively reviewed 12 hips in 12 patients who underwent large-diameter metal-on-metal (L-MoM) total hip replacement between May 2007 and October 2009. Eight of the 12 patients (8 hips; 66.7%) had Parkinson's disease and 4 patients (4 hips; 33.3%) were affected with poliomyelitis. Results: The followup time was 5.2 years (range 3.6-6.0 years). At the latest followup, all the patients showed satisfactory clinical and radiographic results, with pain relief. No complications, such as dislocation or aseptic loosening occurred. Conclusion: We believe the use of L-MoM can diminish the rate of instability or dislocation, after operation. The L-MoM is an option for patients with Parkinson's disease and poliomyelitis with femoral neck fracture. PMID:25404774

  16. Metal on metal total hip arthroplasty and a large groin mass: Not always adverse reaction to metallic debris

    PubMed Central

    Krishnan, Harry; Magnussen, Alex; Sharma, Aadhar; Skinner, John

    2014-01-01

    Due to their improved wear rates, Metal-on-metal bearings have been increasingly used in the past decade by orthopaedic surgeons carrying out total hip arthroplasty. However there is increasing evidence that there are significant complications associated with such implants. One well documented complication is that of metallic debris leading to pseudotumour formation, however there is less known about associations with other tumours within the pelvis. We present two cases where an intra-pelvic mass in patients with metal-on-metal implants were diagnosed as being of a different aetiology. This highlights the need for careful assessment of such patients in order to guide appropriate management. PMID:25560054

  17. Metallic debris from metal-on-metal total hip arthroplasty regulates periprosthetic tissues

    PubMed Central

    Lohmann, Christoph H; Singh, Gurpal; Willert, Hans-Georg; Buchhorn, Gottfried H

    2014-01-01

    The era of metal-on-metal (MoM) total hip arthroplasty has left the orthopaedic community with valuable insights and lessons on periprosthetic tissue reactions to metallic debris. Various terms have been used to describe the tissue reactions. Sometimes the nomenclature can be confusing. We present a review of the concepts introduced by Willert and Semlitsch in 1977, along with further developments made in the understanding of periprosthetic tissue reactions to metallic debris. We propose that periprosthetic tissue reactions be thought of as (1) gross (metallosis, necrosis, cyst formation and pseudotumour); (2) histological (macrophage-dominated, lymphocyte-dominated or mixed); and (3) molecular (expression of inflammatory mediators and cytokines such as interleukin-6 and tumor necrosis factor-alpha). Taper corrosion and modularity are discussed, along with future research directions to elucidate the antigen-presenting pathways and material-specific biomarkers which may allow early detection and intervention in a patient with adverse periprosthetic tissue reactions to metal wear debris. PMID:25405095

  18. Distributed Analysis of Hip Implants Using Six National and Regional Registries: Comparing Metal-on-Metal with Metal-on-Highly Cross-Linked Polyethylene Bearings in Cementless Total Hip Arthroplasty in Young Patients

    PubMed Central

    Furnes, Ove; Paxton, Elizabeth; Cafri, Guy; Graves, Stephen; Bordini, Barbara; Comfort, Thomas; Rivas, Moises Coll; Banerjee, Samprit; Sedrakyan, Art

    2014-01-01

    Background: The regulation of medical devices has attracted controversy recently because of problems related to metal-on-metal hip implants. There is growing evidence that metal-on-metal implants fail early and cause local and systemic complications. However, the failure associated with metal-on-metal head size is not consistently documented and needs to be communicated to patients and surgeons. The purpose of this study is to compare implant survival of metal on metal with that of metal on highly cross-linked polyethylene. Methods: Using a distributed health data network, primary total hip arthroplasties were identified from six national and regional total joint arthroplasty registries (2001 to 2010). Inclusion criteria were patient age of forty-five to sixty-four years, cementless total hip arthroplasties, primary osteoarthritis diagnosis, and exclusion of the well-known outlier implant ASR (articular surface replacement). The primary outcome was revision for any reason. A meta-analysis of survival probabilities was performed with use of a fixed-effects model. Metal-on-metal implants with a large head size of >36 mm were compared with metal-on-highly cross-linked polyethylene implants. Results: Metal-on-metal implants with a large head size of >36 mm were used in 5172 hips and metal-on-highly cross-linked polyethylene implants were used in 14,372 hips. Metal-on-metal total hip replacements with a large head size of >36 mm had an increased risk of revision compared with metal-on-highly cross-linked polyethylene total hip replacements with more than two years of follow-up, with no difference during the first two years after implantation. The results of the hazard ratios (and 95% confidence intervals) from the multivariable model at various durations of follow-up were 0.95 (0.74 to 1.23) at zero to two years (p = 0.698), 1.42 (1.16 to 1.75) at more than two years to four years (p = 0.001), 1.78 (1.45 to 2.19) at more than four years to six years (p < 0.001), and 2.15 (1.63 to 2.83) at more than six years to seven years (p < 0.001). Conclusions: We conducted a comparison of large-head-size, metal-on-metal implants and metal-on-highly cross-linked polyethylene implants in younger patients with uncemented fixation. We found consistent and strong evidence worldwide that large-head-size, metal-on-metal implants were associated with increased risk of revision after two years compared with metal-on-highly cross-linked polyethylene implants, with the effect becoming more pronounced over time. PMID:25520416

  19. 2008 John Charnley Award: Metal Ion Levels After Metal-on-Metal Total Hip Arthroplasty: A Randomized Trial

    PubMed Central

    Engh, C. Anderson; MacDonald, Steven J.; Thompson, Abigail; Naudie, Douglas; Engh, Charles A.

    2008-01-01

    Metal-on-metal bearing total hip arthroplasty is performed more commonly than in the past. There may be manufacturing differences such as clearance, roughness, metallurgy, and head size that affect performance. In a prospective, randomized trial, we compared 2-year postoperative ion levels for a 28-mm metal-on-polyethylene bearing with 28-mm and 36-mm metal-on-metal bearings. We measured serum, erythrocyte, and urine ion levels. We observed no difference in the ion levels for the 28-mm and 36-mm metal-on-metal bearings. The ion levels in these patients were lower than reported for most other metal-on-metal bearings. Although both erythrocyte and serum cobalt increased, erythrocyte chromium and erythrocyte titanium did not increase despite a four- to sixfold serum chromium and a three- to fourfold serum titanium increase. This may represent a threshold level for serum chromium and serum titanium below which erythrocytes are not affected. Level of Evidence: Level I, therapeutic study. See the Guidelines for Authors for a complete description of levels of evidence. PMID:18855089

  20. Increased risk of revision of cementless stemmed total hip arthroplasty with metal-on-metal bearings

    PubMed Central

    Pedersen, Alma B; Mkel, Keijo; Eskelinen, Antti; Havelin, Leif Ivar; Furnes, Ove; Krrholm, Johan; Garellick, Gran; Overgaard, Sren

    2015-01-01

    Background and purpose Data from the national joint registries in Australia and England and Wales have revealed inferior medium-term survivorship for metal-on-metal (MoM) total hip arthroplasty (THA) than for metal-on-polyethylene (MoP) THA. Based on data from the Nordic Arthroplasty Register Association (NARA), we compared the revision risk of cementless stemmed THA with MoM and MoP bearings and we also compared MoM THA to each other. Patients and methods We identified 32,678 patients who were operated from 2002 through 2010 with cementless stemmed THA with either MoM bearings (11,567 patients, 35%) or MoP bearings (21,111 patients, 65%). The patients were followed until revision, death, emigration, or the end of the study period (December 31, 2011), and median follow-up was 3.6 (interquartile range (IQR): 2.44.8) years for MoM bearings and 3.4 (IQR: 2.05.8) years for MoP bearings. Multivariable regression in the presence of competing risk of death was used to assess the relative risk (RR) of revision for any reason (with 95% confidence interval (CI)). Results The cumulative incidence of revision at 8 years of follow-up was 7.0% (CI: 6.08.1) for MoM bearings and 5.1% (CI: 4.75.6) for MoP bearings. At 6 years of follow-up, the RR of revision for any reason was 1.5 (CI: 1.31.7) for MoM bearings compared to MoP bearings. The RR of revision for any reason was higher for the ASR (adjusted RR = 6.4, CI: 5.08.1), the Conserve Plus (adjusted RR = 1.7, CI: 1.12.5) and other acetabular components (adjusted RR = 2.4, CI: 1.53.9) than for MoP THA at 6 years of follow-up. Interpretation At medium-term follow-up, the survivorship for cementless stemmed MoM THA was inferior to that for MoP THA, and metal-related problems may cause higher revision rates for MoM bearings with longer follow-up. PMID:25715878

  1. Magnetic resonance imaging of painful metal-on-metal total hip replacement.

    PubMed

    Nikolaou, Vassilios S; Petit, Alain; Khoury, Viviane; Blain-Pare, Etienne; Zukor, David J; Huk, Olga L; Antoniou, John

    2015-02-01

    Consecutive patients that had primary metal-on-metal (MoM) or metal-on-polyethylene (MoP) hip arthroplasty were prospectively enrolled to this study. All operated hips were evaluated with MRI by one radiologist who was blinded to the radiographic findings and clinical symptoms. Three groups of patients were formed: (1) thirteen MoM THRs in 13 patients with groin pain (Group 1), (2) ten MoM THRs in 10 patients with no pain (Group 2), (3) five MoP THRs in 4 patients without pain (control group). Abnormal MRI findings were distributed in all groups in a balanced way, irrespective of the patients' symptoms, prostheses, or metal ion levels. Two patients from Group 1 and one patient of Group 3 (control group) were diagnosed with a large periprosthetic mass (pseudotumor). PMID:24906294

  2. Understanding the differences between the wear of metal-on-metal and ceramic-on-metal total hip replacements.

    PubMed

    Figueiredo-Pina, C G; Yan, Y; Neville, A; Fisher, J

    2008-04-01

    Hip simulator studies have been carried out extensively to understand and test artificial hip implants in vitro as an efficient alternative to obtaining long-term results in vivo. Recent studies have shown that a ceramic-on-metal material combination lowers the wear by up to 100 times in comparison with a typical metal-on-metal design. The reason for this reduction remains unclear and for this reason this study has undertaken simple tribometer tests to understand the fundamental material loss mechanisms in two material combinations: metal-on-metal and ceramic-on-ceramic. A simple-configuration reciprocating pin-on-plate wear study was performed under open-circuit potential (OCP) and with applied cathodic protection (CP) in a serum solution using two tribological couples: firstly, cobalt-chromium (Co-Cr) pins against Co-Cr plates; secondly, Co-Cr pins against alumina (Al2O3) plates. The pin and plate surfaces prior to and after testing were examined by profilometry and scanning electron microscopy. The results showed a marked reduction in wear when CP was applied, indicating that total material degradation under the OCP condition was attributed to corrosion processes. The substitution of the Co-Cr pin with an Al2O3 plate also resulted in a dramatic reduction in wear, probably due to the reduction in the corrosion-wear interactions between the tribological pair. PMID:18491698

  3. Cup-neck impingement due to the malposition of the implant as a possible mechanism for metallosis in metal-on-metal total hip arthroplasty.

    PubMed

    Onda, Kazunori; Nagoya, Satoshi; Kaya, Mitsunori; Yamashita, Toshihiko

    2008-04-01

    The metal-on-metal bearing total hip prosthesis is expected to reduce the risk of debris-related osteolysis. However, several reports demonstrated that the socket-stem impingement in the metal-on-metal prosthesis due to the implant malposition results in titanium wear debris and secondary metallosis. In this article, we presented a case of massive metallosis due to metal-on-metal impingement. A 60-year woman had severe hip pain due to fracture of the greater trochanter. We planned a revision of the metal-on-metal inlay. Intraoperatively, the trochanteric bursa and joint space were found to be stained black. Black stained granulation tissue was observed between the femoral stem and the great trochanter. Intraoperatively, notching was noticed on both the posteroinferior aspect of the neck of the femoral component and the anterior aspect of the metal liner and polyethylene core. The notch corresponded to the position of impingement between the socket and the femoral neck during the maximum extension of the hip. To clarify the mechanism of cup-neck impingement, the alignment of the prosthesis and pelvic tilt were evaluated. The cup was placed in too much anteverted position. In addition, increased posterior tilt of pelvis in the standing position made the anteversion of the acetabular cup more significant, which enhanced the cup-neck impingement during the gait. Careful attention is necessary for implant alignment and pelvic tilt especially in metal-on-metal-bearing total hip arthroplasty. PMID:19292272

  4. Mortality rates at 10 years after metal-on-metal hip resurfacing compared with total hip replacement in England: retrospective cohort analysis of hospital episode statistics

    PubMed Central

    2013-01-01

    Objectives To compare 10 year mortality rates among patients undergoing metal-on-metal hip resurfacing and total hip replacement in England. Design Retrospective cohort study. Setting English hospital episode statistics database linked to mortality records from the Office for National Statistics. Population All adults who underwent primary elective hip replacement for osteoarthritis from April 1999 to March 2012. The exposure of interest was prosthesis type: cemented total hip replacement, uncemented total hip replacement, and metal-on-metal hip resurfacing. Confounding variables included age, sex, Charlson comorbidity index, rurality, area deprivation, surgical volume, and year of operation. Main outcome measures All cause mortality. Propensity score matching was used to minimise confounding by indication. Kaplan-Meier plots estimated the probability of survival up to 10 years after surgery. Multilevel Cox regression modelling, stratified on matched sets, described the association between prosthesis type and time to death, accounting for variation across hospital trusts. Results 7437 patients undergoing metal-on-metal hip resurfacing were matched to 22 311 undergoing cemented total hip replacement; 8101 patients undergoing metal-on-metal hip resurfacing were matched to 24 303 undergoing uncemented total hip replacement. 10 year rates of cumulative mortality were 271 (3.6%) for metal-on-metal hip resurfacing versus 1363 (6.1%) for cemented total hip replacement, and 239 (3.0%) for metal-on-metal hip resurfacing versus 999 (4.1%) for uncemented total hip replacement. Patients undergoing metal-on-metal hip resurfacing had an increased survival probability (hazard ratio 0.51 (95% confidence interval 0.45 to 0.59) for cemented hip replacement; 0.55 (0.47 to 0.65) for uncemented hip replacement). There was no evidence for an interaction with age or sex. Conclusions Patients with hip osteoarthritis undergoing metal-on-metal hip resurfacing have reduced mortality in the long term compared with those undergoing cemented or uncemented total hip replacement. This difference persisted after extensive adjustment for confounding factors available in our data. The study results can be applied to matched populations, which exclude patients who are very old and have had complex total hip replacements. Although residual confounding is possible, the observed effect size is large. These findings require validation in external cohorts and randomised clinical trials. PMID:24284336

  5. Arthroprosthetic cobaltism and pseudotumour also occur in patients with small diameter femoral ball head metal-on-metal total hip arthroplasties

    PubMed Central

    Roessler, Philip P; Witt, Florian; Efe, Turgay; Schmitt, Jan

    2014-01-01

    Metal-on-metal implants have been widely discredited in public during the past few months. At the same time patients' awareness has risen leading to an increased number of consultations regarding the topic. As hip resurfacings and total hip arthroplasties with large diameter femoral ball heads are already known for excessive metal wear, even small diameter ball heads with low friction get into focus now. We report a case of a 75-year-old man with recurrent hip pain almost 14 years after low friction metal-on-metal total hip arthroplasty. In addition to elevated serum cobalt levels, a type IV sensitivity reaction to cobalt could be noted. Explantation of a highly worn small diameter femoral ball head as well as development of the so-called pseudotumour indicate that all patients should be screened for signs of metal wear regardless of their specific risk factors or the type of metal-on-metal implant. PMID:24682139

  6. Prediction of contact mechanics in metal-on-metal Total Hip Replacement for parametrically comprehensive designs and loads.

    PubMed

    Donaldson, Finn E; Nyman, Edward; Coburn, James C

    2015-07-16

    Manufacturers and investigators of Total Hip Replacement (THR) bearings require tools to predict the contact mechanics resulting from diverse design and loading parameters. This study provides contact mechanics solutions for metal-on-metal (MoM) bearings that encompass the current design space and could aid pre-clinical design optimization and evaluation. Stochastic finite element (FE) simulation was used to calculate the head-on-cup contact mechanics for five thousand combinations of design and loading parameters. FE results were used to train a Random Forest (RF) surrogate model to rapidly predict the contact patch dimensions, contact area, pressures and plastic deformations for arbitrary designs and loading. In addition to widely observed polar and edge contact, FE results included ring-polar, asymmetric-polar, and transitional categories which have previously received limited attention. Combinations of design and load parameters associated with each contact category were identified. Polar contact pressures were predicted in the range of 0-200 MPa with no permanent deformation. Edge loading (with subluxation) was associated with pressures greater than 500 MPa and induced permanent deformation in 83% of cases. Transitional-edge contact (with little subluxation) was associated with intermediate pressures and permanent deformation in most cases, indicating that, even with ideal anatomical alignment, bearings may face extreme wear challenges. Surrogate models were able to accurately predict contact mechanics 18,000 times faster than FE analyses. The developed surrogate models enable rapid prediction of MoM bearing contact mechanics across the most comprehensive range of loading and designs to date, and may be useful to those performing bearing design optimization or evaluation. PMID:25980556

  7. Evaluation of the wear properties of a metal-on-metal total joint replacement system and in vitro macrophage response to resultant wear particles

    NASA Astrophysics Data System (ADS)

    St. John, Kenneth Raymond

    The wear of the polyethylene in total joint prostheses has been a source of morbidity and early device failure which has been extensively reported in the last ten to twelve years. While research continues to attempt to reduce the wear of polyethylene joint bearing surfaces by modifications in polymer processing, there is a renewed interest in the use of metal-on-metal bearing couples for hip replacement devices. This study investigated the in vitro wear resistance of two cobalt/chromium/molybdenum alloys, which differed primarily in the carbon content, as potential alloys for use in such a metal-on-metal hip bearing couple. The results showed that the alloy with the higher (0.25%) carbon content was more wear resistant and this alloy was chosen for testing in a hip simulator system which modeled the loads and motions which might be exerted on a clinically implanted hip replacement. Comparison of the results of metal-on-polyethylene specimens to metal-on-metal specimens showed that the volumetric wear of the metal-on-polyethylene bearing couple over 5,000,000 cycles was 110--180 times as great as that for the metal bearing couple. Polyethylene and metal particles retrieved from either pin-on-disk testing lubricant or hip simulator testing lubricant were cleaned and examined for consistency with the particles reported by other laboratories for particles from periprosthetic tissues and found to be similar. The particles were then added to macrophage (J774a) cell cultures and the release of Prostaglandin E2, Interleukin-6, and Tumor Necrosis Factor alpha measured for each experiment in response to the particles. The cell mediators released by the cells was found to correlate with the dosage of particles and the chemical identity of the particles. Most of the cellular response to the polyethylene particles seemed to be as a result of phagocytosis of the particles while most of the response to metal particles seemed to be related to cytotoxicity of the particles. Based upon the results of this study, metal-on-metal hip prostheses prepared from the high carbon cobalt/chromium alloy (CCM+) that was investigated seem to hold sufficient promise to justify human clinical trials.

  8. Quantifying Gait Quality in Patients with Large-Head and Conventional Total Hip Arthroplasty-A Prospective Cohort Study.

    PubMed

    Jensen, Carsten; Penny, Jeannette ; Nielsen, Dennis B; Overgaard, Sren; Holsgaard-Larsen, Anders

    2015-12-01

    We used the Gait Deviation Index (GDI) as method to compare preoperative to postoperative gait changes after uncemented 50mm (median) large-head and 28/32mm total hip arthroplasty (THA). We also identified predictors of improvements in GDI. Gait analysis and patient-reported (WOMAC) data were recorded in 35 patients before, 2 and 6-months after treatment. Twenty age-matched adults provided normative gait data. Contrary to our hypothesis, patients who received large-head THA had less improvement in GDI compared with patients who received 28/32mm THA. The preoperative GDI score was identified as a predictor of postoperative GDI improvement, while WOMAC, age, gender and walking speed were not. This study provides useful information for clinicians and rehabilitation specialists about gait improvement that can be expected after THA. PMID:26278486

  9. A longitudinal study of MARS MRI scanning of soft-tissue lesions around metal-on-metal total hip arthroplasties and disease progression.

    PubMed

    Briant-Evans, T W; Lyle, N; Barbur, S; Hauptfleisch, J; Amess, R; Pearce, A R; Conn, K S; Stranks, G J; Britton, J M

    2015-10-01

    We investigated the changes seen on serial metal artefact reduction magnetic resonance imaging scans (MARS-MRI) of metal-on-metal total hip arthroplasties (MoM THAs). In total 155 THAs, in 35 male and 100 female patients (mean age 70.4 years, 42 to 91), underwent at least two MRI scans at a mean interval of 14.6 months (2.6 to 57.1), at a mean of 48.2 months (3.5 to 93.3) after primary hip surgery. Scans were graded using a modification of the Oxford classification. Progression of disease was defined as an increase in grade or a minimum 10% increase in fluid lesion volume at second scan. A total of 16 hips (30%) initially classified as 'normal' developed an abnormality on the second scan. Of those with 'isolated trochanteric fluid' 9 (47%) underwent disease progression, as did 7 (58%) of 'effusions'. A total of 54 (77%) of hips initially classified as showing adverse reactions to metal debris (ARMD) progressed, with higher rates of progression in higher grades. Disease progression was associated with high blood cobalt levels or an irregular pseudocapsule lining at the initial scan. There was no association with changes in functional scores. Adverse reactions to metal debris in MoM THAs may not be as benign as previous reports have suggested. Close radiological follow-up is recommended, particularly in high-risk groups. PMID:26430006

  10. Does Choice of Head Size and Neck Geometry Affect Stem Migration in Modular Large-Diameter Metal-on-Metal Total Hip Arthroplasty? A Preliminary Analysis

    PubMed Central

    Georgiou, CS; Evangelou, KG; Theodorou, EG; Provatidis, CG; Megas, PD

    2012-01-01

    Due to their theoretical advantages, hip systems combining modular necks and large diameter femoral heads have gradually gained popularity. However, among others, concerns regarding changes in the load transfer patterns were raised. Recent stress analyses have indeed shown that the use of modular necks and big femoral heads causes significant changes in the strain distribution along the femur. Our original hypothesis was that these changes may affect early distal migration of a modular stem. We examined the effect of head diameter and neck geometry on migration at two years of follow-up in a case series of 116 patients (125 hips), who have undergone primary Metal-on-Metal total hip arthroplasty with the modular grit-blasted ProfemurE stem combined with large-diameter heads (>36 mm). We found that choice of neck geometry and head diameter has no effect on stem migration. A multivariate regression analysis including the potential confounding variables of the body mass index, bone quality, canal fill and stem positioning revealed only a negative correlation between subsidence and canal fill in midstem area. Statistical analysis, despite its limitations, did not confirm our hypothesis that choice of neck geometry and/or head diameter affects early distal migration of a modular stem. However, the importance of correct stem sizing was revealed. PMID:23284597

  11. The Latest Lessons Learned from Retrieval Analyses of Ultra-High Molecular Weight Polyethylene, Metal-on-Metal, and Alternative Bearing Total Disc Replacements

    PubMed Central

    Kurtz, Steven M.; Toth, Jeffrey M.; Siskey, Ryan; Ciccarelli, Lauren; MacDonald, Dan; Isaza, Jorge; Lanman, Todd; Punt, Ilona; Steinbeck, Marla; Goffin, Jan; van Ooij, Andr

    2012-01-01

    Knowledge regarding the in vivo performance and periposthetic tissue response of cervical and lumbar total disc replacements (TDRs) continues to expand. This review addresses the following four main questions: 1) What are the latest lessons learned from polyethylene in large joints and how are they relevant to current TDRs? 2) What are the latest lessons learned regarding adverse local tissue reactions from metal-on-metal, CoCr bearings in large joints and how are they relevant to current TDRs? 3) What advancements have been made in understanding the in vivo performance of alternative biomaterials, such as stainless steel and polycarbonate urethane, for TDRs in the past five years? 4) How has retrieval analysis of all these various artificial disc bearing technologies advanced the state of the art in preclinical testing of TDRs? The study of explanted artificial discs and their associated tissues can help inform bearing selection as well as the design of future generations of disc arthroplasty. Analyzing retrieved artificial discs is also essential for validating preclinical test methods. PMID:22904606

  12. Adverse reaction to metal debris after ReCap-M2A-Magnum large-diameter-head metal-on-metal total hip arthroplasty

    PubMed Central

    2013-01-01

    Background and purpose The clinical findings of adverse reaction to metal debris (ARMD) following large-diameter-head metal-on-metal total hip arthroplasty (LDH MoM THA) may include periarticular fluid collections, soft tissue masses, and gluteal muscle necrosis. The ReCap-M2a-Magnum LDH MoM THA was the most commonly used hip device at our institution from 2005 to 2012. We assessed the prevalence of and risk factors for ARMD with this device. Methods 74 patients (80 hips) had a ReCap-M2a-Magnum LDH MoM THA during the period August 2005 to December 2006. These patients were studied with hip MRI, serum chromium and cobalt ion measurements, the Oxford hip score questionnaire, and by clinical examination. The prevalence of ARMD was recorded and risk factors for ARMD were assessed using logistic regression models. The mean follow-up time was 6.0 (5.56.7) years. Results A revision operation due to ARMD was needed by 3 of 74 patients (3 of 80 hips). 8 additional patients (8 hips) had definite ARMD, but revision was not performed. 29 patients (32 hips) were considered to have a probable or possible ARMD. Altogether, 43 of 80 hips had a definite, probable, or possible ARMD and 34 patients (37 hips) were considered not to have ARMD. In 46 of 78 hips, MRI revealed a soft tissue mass or a collection of fluid (of any size). The symptoms clicking in the hip, local hip swelling, and a feeling of subluxation were associated with ARMD. Interpretation ARMD is common after ReCap-M2a-Magnum total hip arthroplasty, and we discourage the use of this device. Asymptomatic patients with a small fluid collection on MRI may not need instant revision surgery but must be followed up closely. PMID:24171688

  13. Ion release in patients with metal-on-metal hip bearings in total joint replacement: a comparison with metal-on-polyethylene bearings.

    PubMed

    Savarino, L; Granchi, D; Ciapetti, G; Cenni, E; Nardi Pantoli, A; Rotini, R; Veronesi, C A; Baldini, N; Giunti, A

    2002-01-01

    Polyethylene (PE) wear has been shown to be a problem in long-term joint replacement using metal-on-PE bearing. The use of metallic heads articulating with metallic cups could solve this problem: success will be enhanced if wear and corrosion of the articulating surfaces are maintained at a low level. New models with metal-on-metal bearing have been proposed, to be used mainly for young subjects: such coupling seems to have a reduced release, but it is unclear yet if the medium-term corrosion rate is really negligible or, on the contrary, it is significantly higher than in the metal-on-PE bearing. Aim of our study was the comparison of ion release in the serum of two groups of patients who had the same type of stable cementless prosthesis, but different bearing: twenty-six patients with metal-on-metal (Group A) and fifteen patients with metal-on-PE bearing (Group B) were examined. The follow-up was 14-38 months for group A and 18-34 months for group B. The serum concentration of chromium (Cr), cobalt (Co) and molybdenum (Mo) was measured. Twenty-two patients before surgery were used for comparison (Group C). The reference values were obtained from a population of twenty-two healthy subjects (Group D). Our findings indicate that metal-on-metal bearings produce a significantly higher systemic release of cobalt and chromium (ng/ml) when compared with levels found in metal-on-PE, pre-surgery and reference groups. Such a high release should induce to improve the bearing materials or, at least, to study the biologic fate of metal ions and consequently their long-term effects. In such a way a risk-to-benefit ratio for the patient could be established. PMID:12209889

  14. Revision of a single type of large metal head metal-on-metal hip prosthesis.

    PubMed

    van Lingen, Christiaan P; Ettema, Harmen B; Bosker, Bart H; Verheyen, Cees C P M

    2015-01-01

    Large-head metal-on-metal (MoM) total hip arthroplasties were introduced because of their purported advantages. Inflammatory pseudotumours occasionally occur after MoM hip arthroplasty and often lead to revision. The purpose of this study was to assess the outcome of revision of large-head MoM total hip arthroplasties after an extensive screening protocol for all MoM articulations with a minimum 2 year follow-up. We identified 50 hips that had undergone large-head MoM total hip arthoplasty and required revision at a mean of 44 months after index operation. Of these, 38 were revised for pseudotumours, 7 for loosening, 2 for infection and 3 for instability. There was bone loss in 44 hips. The majority were revised to a 28 mm metal or ceramic head on a polyethylene-cemented cup. In 12 patients there was a complication. There was a decrease of whole blood cobalt from 20.8 g/L preoperatively to 1.8 g/L 1 year after revision. We found 6 residual masses on routine postoperative CT scans. The indication for revision of this cohort is inevitable but the clinical outcome 2 years after revision for pseudotumour is disappointing. Revising a MoM hip arthroplasty to a conventional cemented polyethylene or dual-mobility cup with bone impaction grafting and a 28 mm head can adequately treat the high ion levels and probably the disease of ARMD. PMID:25907389

  15. Changes in early serum metal ion levels and impact on liver, kidney, and immune markers following metal-on-metal total hip arthroplasty.

    PubMed

    Chen, Zhefeng; Wang, Zhen; Wang, Qing; Cui, Weiding; Liu, Feng; Fan, Weimin

    2014-03-01

    We retrospectively studied 32 consecutive patients (32 hips) who underwent THA with a Durom large-head, MOM articulation between January 2008 and December 2010. Of the patients who underwent THA using a Trilogy metal on polyethylene prosthesis during the same period, 32 were chosen to form the Trilogy group. 32 volunteers were chosen to form the control group. At the last follow-up, serum metal ion levels, liver and kidney function and host immunologic immune responses were evaluated. The mean Co and Cr levels in the Durom group were 4.33- and 1.95-fold higher than those in the Trilogy group. CD3+, CD4+ and CD8+ cell levels in the Durom group were significantly decreased. The INF-? level in the Durom group was significantly higher than that in the Trilogy and control groups. PMID:23993737

  16. Effect of femoral head size on the wear of metal on metal bearings in total hip replacements under adverse edge-loading conditions

    PubMed Central

    Al-Hajjar, Mazen; Fisher, John; Williams, Sophie; Tipper, Joanne L; Jennings, Louise M

    2013-01-01

    Abstract Metal-on-metal (MoM) bearings have shown low-wear rates under standard hip simulator conditions; however, retrieval studies have shown large variations in wear rates and mechanisms. High-wear in vivo has caused catastrophic complications and has been associated with steep cup-inclination angle (rotational malpositioning). However, increasing the cup-inclination angle in vitro has not replicated the increases in wear to the same extent as those observed in retrievals. Clinically relevant wear rates, patterns, and particles were observed in vitro for ceramic-on-ceramic bearings when microseparation (translational malpositioning) conditions were introduced into the gait cycle. In the present study, 28 and 36-mm MoM bearings were investigated under adverse conditions. Increasing the cup angle from 45 to 65 resulted in a significant increase in the wear rate of the 28 mm bearings. However, for the 36 mm bearings, head-rim contact did not occur under the steep cup-angle condition, and the wear rate did not increase. The introduction of microseparation to the gait cycle significantly increased the wear rate of the MoM bearings. Cup angle and head size did not influence the wear rate under microseparation conditions. This study indicated that high-in vivo wear rates were associated with edge loading due to rotational malpositioning such as high-cup-inclination angle and translational malpositioning that could occur due to several surgical factors. Translational malpositioning had a more dominant effect on the wear rate. Preclinical simulation testing should be undertaken with translational and rotational malpositioning conditions as well as standard walking cycle conditions defined by the ISO standard. 2012 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2013. PMID:23281164

  17. A retrospective comparative study of mortality and causes of death among patients with metal-on-metal and metal-on-polyethylene total hip prostheses in primary osteoarthritis after a long-term follow-up

    PubMed Central

    2010-01-01

    Background All patients with total hip arthroplasty (THA), especially those with metal-on-metal (MM) THA, are exposed to metallic particles and ions, which may cause total or site-specific mortality. We analyzed the causes of total and site-specific mortality among a cohort of patients with MM and with metal-on-polyethylene (MP) THA after a long follow-up time. Methods Standardized mortality ratios (SMR) of total and site-specific causes of death were calculated for 579 patients with MM (McKee-Farrar) and 1585 patients with MP (Brunswik, Lubinus) THA for primary osteoarthritis. Results Mean follow-up time was 17.9 years for patients with MM and 16.7 years for patients with MP. Overall SMR was 0.95 for the MM cohort and 0.90 for the MP cohort, as compared to the normal population. Both cohorts showed significantly decreased mortality for the first decade postoperatively, equal mortality over the next 10 years, and significantly increased mortality after 20 years. Patients with MM THA had higher cancer mortality (SMR 1.01) than those with MP THA (SMR 0.66) during the first 20 years postoperatively, but not thereafter. Conclusion Both MM and MP prostheses are safe based on total and site-specific mortality of recipients during the first 20 postoperative years in comparison with the general population. PMID:20416065

  18. Adverse local tissue reaction (ALTR) associated with corrosion products in metal-on-metal and dual modular neck total hip replacements is associated with upregulation of interferon gamma-mediated chemokine signaling.

    PubMed

    Kolatat, Kritti; Perino, Giorgio; Wilner, Gabrielle; Kaplowitz, Elianna; Ricciardi, Benjamin F; Boettner, Friedrich; Westrich, Geoffrey H; Jerabek, Seth A; Goldring, Steven R; Purdue, P Edward

    2015-10-01

    Adverse local tissue reactions (ALTR) associated with tribocorrosion following total hip arthroplasty (THA) have become a significant clinical concern in recent years. In particular, implants featuring metal-on-metal bearing surfaces and modular femoral stems have been reported to result in elevated rates of ALTR. These tribocorrosion-related tissue reactions are characterized by marked necrosis and lymphocytic infiltration, which contrasts sharply with the macrophagic and foreign body giant cell inflammation associated with polyethylene wear particle induced peri-implant osteolysis. In this study, we characterize tribocorrosion-associated ALTR at a molecular level. Gene expression profiling of peri-implant tissue around failing implants identifies upregulation of numerous inflammatory mediators in ALTR, including several interferon gamma inducible factors, most notably the chemokines MIG/CXCL9 and IP-10/CXCL10. This expression profile is distinct from that associated with polyethylene wear induced osteolysis, which is characterized by induction of markers of alternative macrophage activation, such as chitotriosidase (CHIT-1). Importantly, MIG/CXCL9 and IP-10/CXCL10 are also elevated at the protein level in the synovial fluid and, albeit more moderately, the serum, of ALTR patients, raising the possibility that these factors may serve as circulating biomarkers for the early detection of ALTR in at-risk patients. PMID:25940887

  19. Similar incidence of periprosthetic fluid collections after ceramic-on-polyethylene total hip arthroplasties and metal-on-metal resurfacing arthroplasties: results of a screening metal artefact reduction sequence-MRI study.

    PubMed

    Bisseling, P; de Wit, B W K; Hol, A M; van Gorp, M J; van Kampen, A; van Susante, J L C

    2015-09-01

    Patients from a randomised trial on resurfacing hip arthroplasty (RHA) (n = 36, 19 males; median age 57 years, 24 to 65) comparing a conventional 28 mm metal-on-metal total hip arthroplasty (MoM THA) (n = 28, 17 males; median age 59 years, 37 to 65) and a matched control group of asymptomatic patients with a 32 mm ceramic-on-polyethylene (CoP) THA (n = 33, 18 males; median age 63 years, 38 to 71) were cross-sectionally screened with metal artefact reducing sequence-MRI (MARS-MRI) for pseudotumour formation at a median of 55 months (23 to 72) post-operatively. MRIs were scored by consensus according to three different classification systems for pseudotumour formation. Clinical scores were available for all patients and metal ion levels for MoM bearing patients. Periprosthetic lesions with a median volume of 16 mL (1.5 to 35.9) were diagnosed in six patients in the RHA group (17%), one in the MoM THA group (4%) and six in the CoP group (18%). The classification systems revealed no clear differences between the groups. Solid lesions (n = 3) were exclusively encountered in the RHA group. Two patients in the RHA group and one in the MoM THA group underwent a revision for pseudotumour formation. There was no statistically significant relationship between clinical scoring, metal ion levels and periprosthetic lesions in any of the groups. Periprosthetic fluid collections are seen on MARS-MRI after conventional CoP THA and RHA and may reflect a soft-tissue collection or effusion. Currently available MRI classification systems seem to score these collections as pseudotumours, causing an-overestimatation of the incidence of pseudotumours. PMID:26330582

  20. High rate of revision and a high incidence of radiolucent lines around Metasul metal-on-metal total hip replacements: results from a randomised controlled trial of three bearings after seven years.

    PubMed

    Bjorgul, K; Novicoff, W N; Andersen, S T; Ahlund, O R; Bunes, A; Wiig, M; Brevig, K

    2013-07-01

    A total of 397 hips were randomised to receive Metasul metal-on-metal (MoM), metal-on-conventional polyethylene (MoP) or ceramic-on-polyethylene (CoP) bearings using a cemented triple-tapered polished femoral component (MS-30). There were 129 MoM hips in 123 patients (39 male and 84 female, mean age 63.3 years (40.7 to 72.9)), 137 MoP hips in 127 patients (39 male and 88 female, mean age 62.8 years (24.5 to 72.7)) and 131 CoP hips in 124 patients (51 male and 73 female, mean age 63.9 years (30.6 to 73.8)). All acetabular components were cemented Weber polyethylene components with the appropriate inlay for the MoM articulation. Clinical evaluation was undertaken using the Harris hip score (HHS) and radiological assessments were made at two, five and seven years. The HHS and radiological analysis were available for 341 hips after seven years. The MoM group had the lowest mean HHS (p = 0.124), a higher rate of revision (p < 0.001) and a higher incidence of radiolucent lines in unrevised hips (p < 0.001). In all, 12 revisions had been performed in 12 patients: eight in the MoM group (four for infection, four for aseptic loosening, three in the MoP group (one each of infection, dislocation and pain) and one in the CoP group (infection). Our findings reveal no advantage to the MoM bearing and identified a higher revision rate and a greater incidence of radiolucent lines than with the other articulations. We recommend that patients with a 28 mm Metasul MoM bearing be followed carefully. PMID:23814237

  1. Metal-on-polyethylene versus metal-on-metal bearing surfaces in total hip arthroplasty: a prospective randomised study investigating metal ion levels and chromosomal aberrations in peripheral lymphocytes.

    PubMed

    Briggs, T W R; Hanna, S A; Kayani, B; Tai, S; Pollock, R C; Cannon, S R; Blunn, G W; Carrington, R W J

    2015-09-01

    The long term biological effects of wear products following total hip arthroplasty (THA) are unclear. However, the indications for THA are expanding, with increasingly younger patients undergoing the procedure. This prospective, randomised study compared two groups of patients undergoing THA after being randomised to receive one of two different bearing surfaces: metal-on-polyethylene (MoP) n = 22 and metal-on-metal (MoM) n = 23. We investigated the relationship between three variables: bearing surface (MoP vs MoM), whole blood levels of chromium (Cr) and cobalt (Co) and chromosomal aberrations in peripheral lymphocyte pre-operatively and at one, two and five years post-surgery. Our results demonstrated significantly higher mean cobalt and chromium (Co and Cr) blood levels in the MoM group at all follow-up points following surgery (p < 0.01), but there were no significant differences in the chromosomal aberration indices between MoM and MoP at two or five years (two years: p = 0.56, p = 0.08, p = 0.91, p = 0.51 and five years: p = 0.086, p = 0.73, p = 0.06, p = 0.34) for translocations, breaks, loss and gain of chromosomes respectively. Regression analysis showed a strong linear relationship between Cr levels and the total chromosomal aberration indices in the MoM group (R(2) = 0.90016), but this was not as strong for Co (R(2) = 0.68991). In the MoP group, the analysis revealed a poor relationship between Cr levels and the total chromosomal aberration indices (R(2) = 0.23908) but a slightly stronger relationship for Co (R(2) = 0.64292). Across both groups, Spearman's correlation detected no overall association between Co and Cr levels and each of the studied chromosomal aberrations. There remains no clear indication which THA bearing couple is the most biocompatible, especially in young active patients. While THA continues to be very successful at alleviating pain and restoring function, the long-term biological implications of the procedure still require further scrutiny. PMID:26330583

  2. Metal-on-Metal Hip Resurfacing Arthroplasty

    PubMed Central

    Sehatzadeh, S; Kaulback, K; Levin, L

    2012-01-01

    Background Metal-on-metal (MOM) hip resurfacing arthroplasty (HRA) is in clinical use as an appropriate alternative to total hip arthroplasty in young patients. In this technique, a metal cap is placed on the femoral head to cover the damaged surface of the bone and a metal cup is placed in the acetabulum. Objectives The primary objective of this analysis was to compare the revision rates of MOM HRA using different implants with the benchmark set by the National Institute of Clinical Excellence (NICE). The secondary objective of this analysis was to review the literature regarding adverse biological effects associated with implant material. Review Methods A literature search was performed on February 13, 2012, to identify studies published from January 1, 2009, to February 13, 2012. Results The revision rates for MOM HRA using 6 different implants were reviewed. The revision rates for MOM HRA with 3 implants met the NICE criteria, i.e., a revision rate of 10% or less at 10 years. Two implants had short-term follow-ups and MOM HRA with one of the implants failed to meet the NICE criteria. Adverse tissue reactions resulting in failure of the implants have been reported by several studies. With a better understanding of the factors that influence the wear rate of the implants, adverse tissue reactions and subsequent implant failure can be minimized. Many authors have suggested that patient selection and surgical technique affect the wear rate and the risk of tissue reactions. The biological effects of high metal ion levels in the blood and urine of patients with MOM HRA implants are not known. Studies have shown an increase in chromosomal aberrations in patients with MOM articulations, but the clinical implications and long-term consequences of this increase are still unknown. Epidemiological studies have shown that patients with MOM HRA implants did not have an overall increase in mortality or risk of cancer. There is insufficient clinical data to confirm the teratogenicity of MOM implants in humans. Conclusions Metal-on-metal HRA can be beneficial for appropriately selected patients, provided the surgeon has the surgical skills required for performing this procedure. Plain Language Summary There are many young patients with hip diseases who need to have hip replacement surgery. Although a traditional hip replacement is an acceptable procedure for these patients, some surgeons prefer using a newer technique in young patients called hip resurfacing. In this technique, instead of removing the head of the femoral bone, a metal cap is placed on the femoral head to cover the damaged surface of the bone and a metal cup is placed in the hip socket, similar to the cups used in traditional hip replacement. The analysis of the revision rates (i.e., how soon and in how many patients the surgery needs to be redone) and safety of resurfacing implants showed that generally these implants can last 10 years or more for the majority of young people. Good outcomes can be expected when skilled surgeons perform the surgery in properly selected patients. However, since these implants are made of metal (cobalt and chromium alloy), there is concern about excess metal debris production due to friction between the 2 metal components leading to high levels of metal ions in the blood and urine of patients. The production of metal debris may result in inflammation in the joint or development of a benign soft tissue mass leading to implant failure. However, it has been shown that this risk can be reduced by proper positioning of the implant and the careful selection of patients for this procedure. Little is known about the long-term biological effects of high levels of metal ions in the blood and urine of patients who have received metal implants. There is concern about potential increases in the risk of cancer and the risk of fetal abnormalities, but these effects have not been established yet. However, since cobalt and chromium can pass the placental barrier, implants that are not metal-on-metal are recommended for women at childbearing ages if they need a hip replacement. PMID:23074429

  3. Edge loading in metal-on-metal hips: low clearance is a new risk factor

    PubMed Central

    Zografos, Angelos; Sayles, Ritchie S; Hart, Alister; Cann, Philippa

    2012-01-01

    The revision rate of large head metal-on-metal and resurfacing hips are significantly higher than conventional total hip replacements. The revision of these components has been linked to high wear caused by edge loading; which occurs when the headcup contact patch extends over the cup rim. There are two current explanations for this; first, there is loss of entrainment of synovial fluid resulting in breakdown of the lubricating film and second, edge loading results in a large local increase in contact pressure and consequent film thickness reduction at the cup rim, which causes an increase in wear. This paper develops a method to calculate the distance between the joint reaction force vector and the cup rim the contact patch centre to rim (CPCR) distance. However, the critical distance for the risk of edge loading is the distance from the contact patch edge to rim (CPER) distance. An analysis of explanted hip components, divided into edge worn and non-edge-worn components showed that there was no statistical difference in CPCR values, but the CPER value was significantly lower for edge worn hips. Low clearance hips, which have a more conformal contact, have a larger diameter contact patch and thus are more at risk of edge loading for similarly positioned hips. PMID:22558836

  4. Dislocation of large diameter metal-on-metal bearings an indicator of metal reaction?

    PubMed

    Theruvil, Bipin; Vasukutty, Nijil; Hancock, Nick; Higgs, David; Dunlop, Douglas G; Latham, Jeremy M

    2011-09-01

    We report 3 patients who underwent total hip arthroplasty (THA) using large diameter metal-on-metal bearing. These patients initially presented with pain but went on to develop dislocation of the THA while awaiting investigations. Any pain following metal-on-metal bearing THA should be taken seriously and should trigger investigations to identify a metal reaction. If left untreated, these reactions can cause progressive soft tissue necrosis leading to instability. These patients should be considered for early revision of the bearing surface to prevent further soft tissue damage. PMID:21036007

  5. Cancer incidence and cause-specific mortality in patients with metal-on-metal hip replacements in Finland

    PubMed Central

    2014-01-01

    Background and purpose Metal-on-metal hip implants have been widely used, especially in the USA, Australia, England and Wales, and Finland. We assessed risk of death and updated data on the risk of cancer related to metal-on-metal hip replacements. Patients and methods A cohort of 10,728 metal-on-metal hip replacement patients and a reference cohort of 18,235 conventional total hip replacement patients were extracted from the Finnish Arthroplasty Register for the years 20012010. Data on incident cancer cases and causes of death until 2011 were obtained from the Finnish Cancer Registry and Statistics Finland. The relative risk of cancer and death were expressed as standardized incidence ratio (SIR) and standardized mortality ratio (SMR). SIR/SIR ratios and SMR/SMR ratios, and Poisson regression were used to compare the cancer risk and the risk of death between cohorts. Results The overall risk of cancer in the metal-on-metal cohort was not higher than that in the non-metal-on-metal cohort (RR = 0.91, 95% CI: 0.821.02). The risk of soft-tissue sarcoma and basalioma in the metal-on-metal cohort was higher than in the non-metal-on-metal cohort (SIR/SIR ratio = 2.6, CI: 1.026.4 for soft-tissue sarcoma; SIR/SIR ratio = 1.3, CI: 1.11.5 for basalioma). The overall risk of death in the metal-on-metal cohort was less than that in the non-metal-on-metal cohort (RR = 0.78, CI: 0.690.88). Interpretation The overall risk of cancer or risk of death because of cancer is not increased after metal-on-metal hip replacement. The well-patient effect and selection bias contribute substantially to the findings concerning mortality. Arthrocobaltism does not increase mortality in patients with metal-on-metal hip implants in the short term. However, metal-on-metal hip implants should not be considered safe until data with longer follow-up time are available. PMID:24397743

  6. Metal-on-metal: history, state of the art (2010)

    PubMed Central

    2011-01-01

    The history of metal-on-metal bearing began with K. Mc Kee. Several "episodes" have marked the history of metal-on-metal articulations, and each has contributed to a better understanding of this type of tribology. But to date the indications for this bearing are debated and are subject to reservations because of the existence of permanently elevated levels of circulating metal ions. It therefore appears that the monitoring of our patients, the documentation of our revisions and the collaboration with our industry partners as well as communicating with our biology and pathology colleagues is necessary to help us solve these problems. PMID:21234564

  7. Taper junction failure in large-diameter metal-on-metal bearings

    PubMed Central

    Langton, D. J.; Sidaginamale, R.; Lord, J. K.; Nargol, A. V. F.; Joyce, T. J.

    2012-01-01

    Objectives An ongoing prospective study to investigate failing metal-on-metal hip prostheses was commenced at our centre in 2008. We report on the results of the analysis of the first consecutive 126 failed mated total hip prostheses from a single manufacturer. Methods Analysis was carried out using highly accurate coordinate measuring to calculate volumetric and linear rates of the articular bearing surfaces and also the surfaces of the taper junctions. The relationship between taper wear rates and a number of variables, including bearing diameter and orientation of the acetabular component, was investigated. Results The measured rates of wear and distribution of material loss from the taper surfaces appeared to show that the primary factor leading to taper failure is the increased lever arm acting on this junction in contemporary large-diameter metal-on-metal hip replacements. Conclusions Our analysis suggests that varus stems, laterally engaging taper systems and larger head diameters all contribute to taper failure. PMID:23610672

  8. Graphitic Tribological Layers in Metal-on-Metal Hip Replacements

    NASA Astrophysics Data System (ADS)

    Liao, Y.; Pourzal, R.; Wimmer, M. A.; Jacobs, J. J.; Fischer, A.; Marks, L. D.

    2011-12-01

    Arthritis is a leading cause of disability, and when nonoperative methods have failed, a prosthetic implant is a cost-effective and clinically successful treatment. Metal-on-metal replacements are an attractive implant technology, a lower-wear alternative to metal-on-polyethylene devices. Relatively little is known about how sliding occurs in these implants, except that proteins play a critical role and that there is a tribological layer on the metal surface. We report evidence for graphitic material in the tribological layer in metal-on-metal hip replacements retrieved from patients. As graphite is a solid lubricant, its presence helps to explain why these components exhibit low wear and suggests methods of improving their performance; simultaneously, this raises the issue of the physiological effects of graphitic wear debris.

  9. CoCrMo metal-on-metal hip replacements.

    PubMed

    Liao, Yifeng; Hoffman, Emily; Wimmer, Markus; Fischer, Alfons; Jacobs, Joshua; Marks, Laurence

    2013-01-21

    After the rapid growth in the use of CoCrMo metal-on-metal hip replacements since the second generation was introduced circa 1990, metal-on-metal hip replacements have experienced a sharp decline in the last two years due to biocompatibility issues related to wear and corrosion products. Despite some excellent clinical results, the release of wear and corrosion debris and the adverse response of local tissues have been of great concern. There are many unknowns regarding how CoCrMo metal bearings interact with the human body. This perspective article is intended to outline some recent progresses in understanding wear and corrosion of metal-on-metal hip replacement both in vivo and in vitro. The materials, mechanical deformation, corrosion, wear-assisted corrosion, and wear products will be discussed. Possible adverse health effects caused by wear products will be briefly addressed, as well as some of the many open questions such as the detailed chemistry of corrosion, tribochemical reactions and the formation of graphitic layers. Nowadays we design almost routinely for high performance materials and lubricants for automobiles; humans are at least as important. It is worth remembering that a hip implant is often the difference between walking and leading a relatively normal life, and a wheelchair. PMID:23196425

  10. CoCrMo Metal-on-Metal Hip Replacements

    PubMed Central

    Liao, Yifeng; Hoffman, Emily; Wimmer, Markus; Fischer, Alfons; Jacobs, Joshua; Marks, Laurence

    2012-01-01

    After the rapid growth in the use of CoCrMo metal-on-metal hip replacements since the second generation was introduced circa 1990, metal-on-metal hip replacements have experienced a sharp decline in the last two years due to biocompatibility issues related to wear and corrosion products. Despite some excellent clinical results, the release of wear and corrosion debris and the adverse response of local tissues have been of great concern. There are many unknowns regarding how CoCrMo metal bearings interact with the human body. This perspective article is intended to outline some recent progresses in understanding wear and corrosion of metal-on-metal hip replacement both in-vivo and in-vitro. The materials, mechanical deformation, corrosion, wear-assisted corrosion, and wear products will be discussed. Possible adverse health effects caused by wear products will be briefly addressed, as well as some of the many open questions such as the detailed chemistry of corrosion, tribochemical reactions and the formation of graphitic layers. Nowadays we design almost routinely for high performance materials and lubricants for automobiles; humans are at least as important. It is worth remembering that a hip implant is often the difference between walking and leading a relatively normal life, and a wheelchair. PMID:23196425

  11. Metal-on-metal joint bearings and hematopoetic malignancy

    PubMed Central

    2012-01-01

    Abstract This is a review of the hip arthroplasty era. We concentrate on new metal bearings, surface replacements, and the lessons not learned, and we highlight recent reports on malignancies and joint implants. A low incidence of blood malignancies has been found in bone marrow taken at prosthetic surgery. The incidence is increased after replacement with knee implants that release very low systemic levels of metal ions. A carcinogenic effect of the high levels of metal ions released by large metal-on-metal implants cannot be excluded. Ongoing Swedish implant registry studies going back to 1975 can serve as a basis for evaluation of this risk. PMID:23140092

  12. Independent predictors of revision following metal-on-metal hip resurfacing: a retrospective cohort study using National Joint Registry data.

    PubMed

    Jameson, S S; Baker, P N; Mason, J; Porter, M L; Deehan, D J; Reed, M R

    2012-06-01

    Modern metal-on-metal hip resurfacing has been widely performed in the United Kingdom for over a decade. However, the literature reports conflicting views of the benefits: excellent medium- to long-term results with some brands in specific subgroups, but high failure rates and local soft-tissue reactions in others. The National Joint Registry for England and Wales (NJR) has collected data on all hip resurfacings performed since 2003. This retrospective cohort study recorded survival time to revision from a resurfacing procedure, exploring risk factors independently associated with failure. All patients with a primary diagnosis of osteoarthritis who underwent resurfacing between 2003 and 2010 were included in the analyses. Cox's proportional hazard models were used to analyse the extent to which the risk of revision was related to patient, surgeon and implant covariates. A total of 27 971 hip resurfacings were performed during the study period, of which 1003 (3.59%) underwent revision surgery. In the final adjusted model, we found that women were at greater risk of revision than men (hazard ratio (HR) = 1.30, p = 0.007), but the risk of revision was independent of age. Of the implant-specific predictors, five brands had a significantly greater risk of revision than the Birmingham Hip Resurfacing (BHR) (ASR: HR = 2.82, p < 0.001, Conserve: HR = 2.03, p < 0.001, Cormet: HR = 1.43, p = 0.001, Durom: HR = 1.67, p < 0.001, Recap: HR = 1.58, p = 0.007). Smaller femoral head components were also significantly more likely to require revision (? 44 mm: HR = 2.14, p < 0.001, 45 to 47 mm: HR = 1.48, p = 0.001) than medium or large heads, as were operations performed by low-volume surgeons (HR = 1.36, p < 0.001). Once these influences had been removed, in 4873 male patients < 60 years old undergoing resurfacing with a BHR, the five-year estimated risk of revision was 1.59%. In summary, after adjustment for a range of covariates we found that there were significant differences in the rate of failure between brands and component sizes. Younger male patients had good five-year implant survival when the BHR was used. PMID:22628587

  13. Metal Ion Concentrations in Body Fluids after Implantation of Hip Replacements with Metal-on-Metal Bearing – Systematic Review of Clinical and Epidemiological Studies

    PubMed Central

    Hartmann, Albrecht; Hannemann, Franziska; Lützner, Jörg; Seidler, Andreas; Drexler, Hans; Günther, Klaus-Peter; Schmitt, Jochen

    2013-01-01

    Introduction The use of metal-on-metal (MoM) total hip arthroplasty (THA) increased in the last decades. A release of metal products (i.e. particles, ions, metallo-organic compounds) in these implants may cause local and/or systemic adverse reactions. Metal ion concentrations in body fluids are surrogate measures of metal exposure. Objective To systematically summarize and critically appraise published studies concerning metal ion concentrations after MoM THA. Methods Systematic review of clinical trials (RCTs) and epidemiological studies with assessment of metal ion levels (cobalt, chromium, titanium, nickel, molybdenum) in body fluids after implantation of metalliferous hip replacements. Systematic search in PubMed and Embase in January 2012 supplemented by hand search. Standardized abstraction of pre- and postoperative metal ion concentrations stratified by type of bearing (primary explanatory factor), patient characteristics as well as study quality characteristics (secondary explanatory factors). Results Overall, 104 studies (11 RCTs, 93 epidemiological studies) totaling 9.957 patients with measurement of metal ions in body fluids were identified and analyzed. Consistently, median metal ion concentrations were persistently elevated after implantation of MoM-bearings in all investigated mediums (whole blood, serum, plasma, erythrocytes, urine) irrespective of patient characteristics and study characteristics. In several studies very high serum cobalt concentrations above 50 µg/L were measured (detection limit typically 0.3 µg/L). Highest metal ion concentrations were observed after treatment with stemmed large-head MoM-implants and hip resurfacing arthroplasty. Discussion Due to the risk of local and systemic accumulation of metallic products after treatment with MoM-bearing, risk and benefits should be carefully balanced preoperatively. The authors support a proposed „time out“ for stemmed large-head MoM-THA and recommend a restricted indication for hip resurfacing arthroplasty. Patients with implanted MoM-bearing should receive regular and standardized monitoring of metal ion concentrations. Further research is indicated especially with regard to potential systemic reactions due to accumulation of metal products. PMID:23950923

  14. Wear of surface engineered metal-on-metal hip prostheses.

    PubMed

    Fisher, J; Hu, X Q; Stewart, T D; Williams, S; Tipper, J L; Ingham, E; Stone, M H; Davies, C; Hatto, P; Bolton, J; Riley, M; Hardaker, C; Isaac, G H; Berry, G

    2004-03-01

    The wear of existing metal-on-metal (MOM) hip prostheses (1 mm3/million cycles) is much lower than the more widely used polyethylene-on-metal bearings (30-100 mm3/million cycles). However, there remain some potential concerns about the toxicity of metal wear particles and elevated metal ion levels, both locally and systemically in the human body. The aim of this study was to investigate the wear, wear debris and ion release of fully coated surface engineered MOM bearings for hip prostheses. Using a physiological anatomical hip joint simulator, five different bearing systems involving three thick (8-12 microm) coatings, TiN, CrN and CrCN, and one thin (2 microm) coating diamond like carbon (DLC) were evaluated and compared to a clinically used MOM cobalt chrome alloy bearing couple. The overall wear rates of the surface engineered prostheses were at least 18-fold lower than the traditional MOM prostheses after 2 million cycles and 36-fold lower after 5 million cycles. Consequently, the volume of wear debris and the ion levels in the lubricants were substantially lower. These parameters were also much lower than in half coated (femoral heads only) systems that have been reported previously. The extremely low volume of wear debris and concentration of metal ions released by these surface engineered systems, especially with CrN and CrCN coatings, have considerable potential for the clinical application of this technology. PMID:15334994

  15. Muscle atrophy and metal-on-metal hip implants

    PubMed Central

    Berber, Reshid; Khoo, Michael; Cook, Erica; Guppy, Andrew; Hua, Jia; Miles, Jonathan; Carrington, Richard; Skinner, John; Hart, Alister

    2015-01-01

    Background and purpose Muscle atrophy is seen in patients with metal-on-metal (MOM) hip implants, probably because of inflammatory destruction of the musculo-tendon junction. However, like pseudotumors, it is unclear when atrophy occurs and whether it progresses with time. Our objective was to determine whether muscle atrophy associated with MOM hip implants progresses with time. Patients and methods We retrospectively reviewed 74 hips in 56 patients (32 of them women) using serial MRI. Median age was 59 (2383) years. The median time post-implantation was 83 (35142) months, and the median interval between scans was 11 months. Hip muscles were scored using the Pfirrmann system. The mean scores for muscle atrophy were compared between the first and second MRI scans. Blood cobalt and chromium concentrations were determined. Results The median blood cobalt was 6.84 (0.2490) ppb and median chromium level was 4.42 (0.2045) ppb. The median Oxford hip score was 34 (548). The change in the gluteus minimus mean atrophy score between first and second MRI was 0.12 (p = 0.002). Mean change in the gluteus medius posterior portion (unaffected by surgical approach) was 0.08 (p = 0.01) and mean change in the inferior portion was 0.10 (p = 0.05). Mean pseudotumor grade increased by 0.18 (p = 0.02). Interpretation Worsening muscle atrophy and worsening pseudotumor grade occur over a 1-year period in a substantial proportion of patients with MOM hip implants. Serial MRI helps to identify those patients who are at risk of developing worsening soft-tissue pathology. These patients should be considered for revision surgery before irreversible muscle destruction occurs. PMID:25588091

  16. On the inflammatory response in metal-on-metal implants

    PubMed Central

    2014-01-01

    Background Metal-on-metal implants are a special form of hip endoprostheses that despite many advantages can entail serious complications due to release of wear particles from the implanted material. Metal wear particles presumably activate local host defence mechanisms, which causes a persistent inflammatory response with destruction of bone followed by a loosening of the implant. To better characterize this inflammatory response and to link inflammation to bone degradation, the local generation of proinflammatory and osteoclast-inducing cytokines was analysed, as was systemic T cell activation. Methods By quantitative RT-PCR, gene expression of cytokines and markers for T lymphocytes, monocytes/macrophages and osteoclasts, respectively, was analysed in tissue samples obtained intraoperatively during exchange surgery of the loosened implant. Peripheral T cells were characterized by cytofluorometry before surgery and 7 to 10 days thereafter. Results At sites of osteolysis, gene expression of cathepsin K, CD14 and CD3 was seen, indicating the generation of osteoclasts, and the presence of monocytes and of T cells, respectively. Also cytokines were highly expressed, including CXCL8, IL-1ß, CXCL2, MRP-14 and CXCL-10. The latter suggest T cell activation, a notion that could be confirmed by detecting a small, though conspicuous population of activated CD4+ cells in the peripheral blood T cells prior to surgery. Conclusion Our data support the concept that metallosis is the result of a local inflammatory response, which according to histomorphology and the composition of the cellular infiltrate classifies as an acute phase of a chronic inflammatory disease. The proinflammatory environment, particularly the generation of the osteoclast-inducing cytokines CXCL8 and IL1-ß, promotes bone resorption. Loss of bone results in implant loosening, which then causes the major symptoms of metallosis, pain and reduced range of motion. PMID:24650243

  17. Assessing the material loss of the modular taper interface in retrieved metal-on-metal hip replacements

    NASA Astrophysics Data System (ADS)

    Bills, Paul J.; Racasan, R.; Tessier, P.; Blunt, L. A.

    2015-06-01

    Measuring the amount of material loss in the case of revised hip replacements is considered to be a prerequisite of understanding and assessing the true in vivo performance of the implant. This paper outlines a method developed by the authors for quantifying taper material loss as well as more general taper interface parameters. Previous studies have mostly relied on visual inspection to assess the material loss at the taper interface, whereas this method aims to characterize any surface and form changes through the use of an out-of-roundness measurement machine. Along with assessing the volumetric wear, maximum linear penetration and taper contact length can also be determined. The method was applied to retrieved large head metal-on-metal femoral heads in order to quantify the material loss at this junction. Material loss from the female femoral head taper can be characterized as a localized area that is in contact with the stem taper surface. The study showed that this method has good repeatability and a low level of interoperability variation between operators.

  18. Wear evaluation of cobalt-chromium alloy for use in a metal-on-metal hip prosthesis.

    PubMed

    St John, Kenneth R; Zardiackas, Lyle D; Poggie, Robert A

    2004-01-15

    Wear of the polyethylene in total joint prostheses has been a source of morbidity and early device failure, which has been extensively reported in the last 20 years. Although research continues to attempt to reduce the wear of polyethylene joint-bearing surfaces by modifications in polymer processing, there is a renewed interest in the use of metal-on-metal bearing couples for hip prostheses. Wear testing of total hip replacement systems involving the couple of metal or ceramic heads on polymeric acetabular components has been performed and reported, but, until recently, there has been little data published for pin-on-disk or hip-simulator wear studies involving the combination of a metallic femoral head component with an acetabular cup composed of the same or a dissimilar metal. This study investigated the in vitro wear resistance of two cobalt/chromium/molybdenum alloys, which differed primarily in the carbon content, as potential alloys for use in a metal-on-metal hip-bearing couple. The results of pin-on-disk testing showed that the alloy with the higher (0.25%) carbon content was more wear resistant, and this alloy was therefore chosen for testing in a hip-simulator system, which modeled the loads and motions that might be exerted clinically. Comparison of the results of metal-on-polyethylene samples to metal-on-metal samples showed that the volumetric wear of the metal-on-polyethylene bearing couple after 5,000,000 cycles was 110-180 times that for the metal-bearing couple. Polyethylene and metal particles retrieved from either the lubricant for pin-on-disk testing or hip simulator testing were characterized and compared with particles retrieved from periprosthetic tissues by other researchers, and found to be similar. Based upon the results of this study, metal-on-metal hip prostheses manufactured from the high carbon cobalt/chromium alloy that was investigated hold sufficient promise to justify human clinical trials. PMID:14689490

  19. Tribolayer Formation in a Metal-on-Metal (MoM) Hip Joint: An Electrochemical Investigation

    PubMed Central

    Mathew, MT; Nagelli, C; Pourzal, R; Fischer, A; Laurent, MP; Jacobs, JJ; Wimmer, MA

    2013-01-01

    The demand for total hip replacement (THR) surgery is increasing in the younger population due to faster rehabilitation and more complete restoration of function. Up to 2009, metal-on-metal (MoM) hip joint bearings were a popular choice due to their design flexibility, post-operative stability and relatively low wear rates. The main wear mechanisms that occur along the bearing surface of MoM joints are tribochemical reactions that deposit a mixture of wear debris, metal ions and organic matrix of decomposed proteins known as a tribolayer. No in-depth electrochemical studies have been reported on the structure and characteristics of this tribolayer or about the parameters involved in its formation. In this study, we conducted an electrochemical investigation of different surfaces (bulk-like: control, nano-crystalline: new implant and tribolayer surface: retrieved implant) made out of two commonly used hip CoCrMo alloys (high-carbon and low-carbon). As per ASTM standard, cyclic polarization tests and electrochemical impedance spectroscopy tests were conducted. The results obtained from electrochemical parameters for different surfaces clearly indicated a reduction in corrosion for the tribolayer surface (Icorr: 0.76 ?A/cm2). Further, polarization resistance (Rp:2.390.60M?/cm2) and capacitance (Cdl:15.200.75 ?F/cm2) indicated variation in corrosion kinetics for the tribolayer surface, that attributed to its structure and stability in a simulated body environment. PMID:24099949

  20. The Durom large diameter head acetabular component: early results with a large-diameter metal-on-metal bearing.

    PubMed

    Berton, C; Girard, J; Krantz, N; Migaud, H

    2010-02-01

    Implantation of a large-diameter femoral head prosthesis with a metal-on-metal bearing surface reduces the risk of dislocation, increases the range of movement, minimises the risk of impingement and, in theory, results in little wear. Between February 2004 and March 2007 we implanted 100 consecutive total hip replacements with a metal-on-metal bearing and a large femoral head into 92 patients. There were 51 men and 41 women with a mean age of 50 years (18 to 70) at the time of surgery. Outcome was assessed using the Western Ontario McMaster University osteoarthritis index and the Harris hip score as well as the Devane activity score. These all improved significantly (p < 0.0001). At the last follow-up there were no cases of dislocation, no impingement, a good range of movement and no osteolysis, but seven revisions, two for infection and five for aseptic loosening. The probability of groin pain increased if the other acetabular component inclination exceeded 50 degrees (p = 0.0007). At 4.8 years of follow-up, the projected survival of the Durom acetabular component, with revision for any reason, was 92.4% (sd 2.8) (95% confidence interval 89.6 to 95.2). The design of the component made it difficult both to orientate and seat, which when combined with a poor porous coating, produced unpredictable fixation and a low survival at five years. PMID:20130309

  1. Does Ion Release Differ Between Hip Resurfacing and Metal-on-metal THA?

    PubMed Central

    Moroni, Antonio; Cadossi, Matteo; Baldini, Nicola; Giannini, Sandro

    2008-01-01

    Modern metal-on-metal hip resurfacing was introduced as a bone-preserving method of joint reconstruction for young and active patients; however, the large diameter of the bearing surfaces is of concern for potential increased metal ion release. We hypothesized there were no differences in serum concentrations of chromium, cobalt, and molybdenum between patients who had metal-on-metal hip resurfacing (Group A; average head diameter, 48mm; median followup, 24months) and patients who had 28-mm metal-on-metal THA (Group B; median followup, 25months). Serum concentrations also were compared with concentrations in healthy subjects. We identified no differences in ion levels between Groups A and B. A distinction was made according to gender. Women showed a higher chromium release in Group A whereas men had a higher cobalt release in Group B. Values obtained from Group A were higher than those of the control subjects. Our data suggest metal-on-metal bearings for THA should not be rejected because of concern regarding potential increased metal ion release; however, patients with elevated ion levels, even without loosening or toxicity, could be at higher risk and should be followed up periodically. Level of Evidence: Level III, therapeutic study. See the Guidelines for Authors for a complete description of levels of evidence. PMID:18196364

  2. Progressive Cardiomyopathy in a Patient With Elevated Cobalt Ion Levels and Bilateral Metal-on-Metal Hip Arthroplasties.

    PubMed

    Mosier, Brian A; Maynard, Lance; Sotereanos, Nicholas G; Sewecke, Jeffrey J

    2016-01-01

    Systemic cobalt toxicity is a rare complication after metal-on-metal (MOM) total hip arthroplasty. Here we present a case of progressive cardiomyopathy, as evidenced by biopsy and cardiac magnetic resonance imaging (MRI), in a patient with bilateral MOM total hip arthroplasties. To our knowledge, it is one of the first cases in which cardiomyopathy resulting from systemic cobalt disease has been shown on MRI. While there is no guideline to unequivocally diagnose cobalt cardiomyopathy, the constellation of findings, including pathologic, biologic, blood levels, imaging, and surgical, all uniformly indicate a unifying diagnosis. The lack of improvement after removal of the prosthetic device supports a diagnosis of permanent myocardial damage, which is consistent with cardiomyopathy of advanced toxic etiology. PMID:26991580

  3. Asymptomatic pseudotumours after metal-on-metal hip resurfacing show little change within one year.

    PubMed

    van der Weegen, W; Brakel, K; Horn, R J; Hoekstra, H J; Sijbesma, T; Pilot, P; Nelissen, R G H H

    2013-12-01

    The aim of this study was to establish the natural course of unrevised asymptomatic pseudotumours after metal-on-metal (MoM) hip resurfacing during a six- to 12-month follow-up period. We used repeated metal artefact reduction sequence (MARS)-magnetic resonance imaging (MRI), serum metal ion analysis and clinical examination to study 14 unrevised hips (mean patient age 52.7 years, 46 to 68, 5 female, 7 male) with a pseudotumour and 23 hips (mean patient age 52.8 years, 38 to 69, 7 female, 16 male) without a pseudotumour. The mean post-operative time to the first MARS-MRI scan was 4.3 years (2.2 to 8.3), and mean time between the first and second MARS-MRI scan was eight months (6 to 12). At the second MRI scan, the grade of severity of the pseudotumour had not changed in 35 hips. One new pseudotumour (Anderson C2 score, moderate) was observed, and one pseudotumour was downgraded from C2 (moderate) to C1 (mild). In general, the characteristics of the pseudotumours hardly changed. Repeated MARS-MRI scans within one year in patients with asymptomatic pseudotumours after MoM hip resurfacing showed little or no variation. In 23 patients without pseudotumour, one new asymptomatic pseudotumour was detected. This is the first longitudinal study on the natural history of pseudotumours using MARS-MRI scans in hip resurfacing, and mirrors recent results for 28 mm diameter MoM total hip replacement. PMID:24293591

  4. New Insights into Wear and Biological Effects of Metal-on-Metal Bearings

    PubMed Central

    Catelas, Isabelle; Wimmer, Markus A.

    2011-01-01

    Background: Despite the renewed interest in metal-on-metal implants in the past two decades, the underlying wear mechanisms and biological effects are still not fully understood. Methods: This paper first reviews the tribology of metal-on-metal bearings, bringing new insights into the interaction of wear and corrosion, and putting the characteristics and the potential origin of wear particles in perspective with the proposed wear mechanisms. It then summarizes the current knowledge on the biological effects of particles and metal ions in relation to these wear mechanisms. Results: Tribochemical reactions play an important role in the wear of metal-on-metal joints. The generated tribomaterial, which progressively forms by mechanical mixing of the uppermost nanocrystalline zone of the metal surface with proteins from the synovial fluid, governs the wear rate and influences the corrosive behavior of the bearing. Nanometer-sized wear particles may initially originate from the passivation layer covering the implant surface and then detach from this tribolayer. The inflammatory response observed surrounding metal-on-metal implants appears to be lower than that around metal-on-polyethylene implants. However, metallic byproducts, which can complex with proteins, may lead to a T lymphocyte-mediated hypersensitivity response. Conclusions: The tribolayer appears to have beneficial effects on the wear rate. Much information has been gained on wear particle characteristics, but the exact mechanisms of particle detachment remain to be further elucidated. Excessive wear along with a hypersensitivity response may be at the origin of the early adverse tissue reactions that have been recently reported in some patients with metal-on-metal implants. Clinical Relevance: Future development of new methods to improve the tribolayer retention and optimize the tribocorrosive properties of the implant may minimize the clinical impact of implant wear and immune responses. PMID:21543694

  5. Influence of the clearance on in-vitro tribology of large diameter metal-on-metal articulations pertaining to resurfacing hip implants.

    PubMed

    Rieker, Claude B; Schön, Rolf; Konrad, Reto; Liebentritt, Gernot; Gnepf, Patric; Shen, Ming; Roberts, Paul; Grigoris, Peter

    2005-04-01

    Large-diameter metal-on-metal articulations may provide an opportunity for wear reduction in total hip implants because earlier studies have shown that the formation of a fluid film that completely separates the bearing surfaces is theoretically possible. In such a lubrication mode and under ideal conditions, there is theoretically no amount of wear. Studies have suggested that the two primary parameters controlling the lubrication mode are the diameter and the clearance of the articulation. The goal of the present study was to experimentally investigate the influence of these two parameters on the wear behavior of large-diameter metal-on-metal articulations pertaining to resurfacing hip implants. The results of this in vitro investigation showed that longer running-in periods and higher amounts of running-in wear were associated with larger clearances. PMID:15833451

  6. Effects of metal-on-metal wear on the host immune system and infection in hip arthroplasty

    PubMed Central

    2010-01-01

    Background and purpose Joint replacement with metal-on-metal (MOM) bearings have gained popularity in the last decades in young and active patients. However, the possible effects of MOM wear debris and its corrosion products are still the subject of debate. Alongside the potential disadvantages such as toxicity, the influences of metal particles and metal ions on infection risk are unclear. Methods We reviewed the available literature on the influence of degradation products of MOM bearings in total hip arthroplasties on infection risk. Results Wear products were found to influence the risk of infection by hampering the immune system, by inhibiting or accelerating bacterial growth, and by a possible antibiotic resistance and heavy metal co-selection mechanism. Interpretation Whether or not the combined effects of MOM wear products make MOM bearings less or more prone to infection requires investigation in the near future. PMID:20860450

  7. Metal-on-Metal Hip Prostheses and Systemic Health: A Cross-Sectional Association Study 8 Years after Implantation

    PubMed Central

    Prentice, Jennifer R.; Clark, Matthew J.; Hoggard, Nigel; Morton, Allison C.; Tooth, Claire; Paley, Martyn N.; Stockley, Ian; Hadjivassiliou, Marios; Wilkinson, J. Mark

    2013-01-01

    There is public concern over the long term systemic health effects of metal released from hip replacement prostheses that use large-diameter metal-on-metal bearings. However, to date there has been no systematic study to determine which organs may be at risk, or the magnitude of any effect. We undertook a detailed cross-sectional health screen at a mean of 8 years after surgery in 35 asymptomatic patients who had previously received a metal-on-metal hip resurfacing (MoMHR) versus 35 individually age and sex matched asymptomatic patients who had received a conventional hip replacement. Total body bone mineral density was 5% higher (mean difference 0.05 g/cm2, P = 0.02) and bone turnover was 14% lower (TRAP 5b, mean difference −0.56IU/L, P = 0.006; osteocalcin, mean difference −3.08 ng/mL, P = 0.03) in the hip resurfacing versus conventional hip replacement group. Cardiac ejection fraction was 7% lower (mean absolute difference −5%, P = 0.04) and left ventricular end-diastolic diameter was 6% larger (mean difference 2.7 mm, P = 0.007) in the hip resurfacing group versus those patients who received a conventional hip replacement. The urinary fractional excretion of metal was low (cobalt 5%, chromium 1.5%) in patients with MoMHR, but creatinine clearance was normal. Diuretic prescription was associated with a 40% increase in the fractional excretion of chromium (mean difference 0.5%, P = 0.03). There was no evidence of difference in neuropsychological, renal tubular, hepatic or endocrine function between groups (P>0.05). Our findings of differences in bone and cardiac function between patient groups suggest that chronic exposure to low elevated metal concentrations in patients with well-functioning MoMHR prostheses may have systemic effects. Long-term epidemiological studies in patients with well-functioning metal on metal hip prostheses should include musculoskeletal and cardiac endpoints to quantitate the risk of clinical disease. PMID:23762480

  8. A retrieval analysis of explanted Durom metal-on-metal hip arthroplasties.

    PubMed

    Matthies, Ashley K; Henckel, Johann; Skinner, John A; Hart, Alister J

    2011-01-01

    Given the recent reports of high failure rates, an improved understanding of the mechanism of failure of large diameter metal-on-metal hip arthroplasties is essential. We present clinical data and tribological analysis of a consecutive series of 74 failed large diameter metal-on-metal hips, comparing the Durom (Zimmer) with the Birmingham hip resurfacing (BHR) (Smith and Nephew). We retrospectively analysed pre-, intra-, and post-operative clinical data and measured the linear wear and component form of the explanted components using a roundness measuring machine. A significantly higher proportion of hips in the Durom group failed as a result of acetabular loosening (p=0.001) and this was supported by evidence of reduced bone in-growth on the backside of the cup. Comparison of roundness measurement revealed that the Durom hip was significantly lower wearing than the BHR (p<0.05) but the Durom femoral components were subject to significantly greater form errors (p<0.001), the pole of the head being flattened by up to 31 microns. Although the Durom hip is low wearing, reduced sphericity of the femoral component may have resulted in equatorial bearing, leading to an increased frictional torque at the cup-bone interface, preventing bone in-growth, and culminating in acetabular loosening. This supports recent clinical findings of high revision rates as a result of acetabular loosening for the Durom metal-on-metal hip system. PMID:22144337

  9. Revision of metal-on-metal hip arthroplasty in a tertiary center

    PubMed Central

    2013-01-01

    Background and purpose Operative findings during revision of metal-on-metal hip arthroplasty (MOMHA) vary widely and can involve massive soft tissue and bone disruption. As a result, planning of theater time and resources is difficult, surgery is challenging, and outcomes are often poor. We describe our experience with revision of MOMHA and provide recommendations for management. Patients and methods We present the findings and outcomes of 39 consecutive MOMHAs (in 35 patients) revised in a tertiary unit (median follow-up time 30 (1254) months). The patients underwent a preoperative work-up including CT, metal artifact reduction sequence (MARS) MRI, and blood metal ion levels. Results We determined 5 categories of failure. 8 of 39 hips had conventional failure mechanisms including infection and impingement. Of the other 31 hips, 14 showed synovitis without significant disruption of soft tissue; 6 had a cystic pseudotumor with significant soft tissue disruption; 7 had significant osteolysis; and 4 had a solid pseudotumor. Each category of failure had specific surgical hazards that could be addressed preoperatively. There were 2 reoperations and 1 patient (2 hips) died of an unrelated cause. Median Oxford hip score (OHS) was 37 (948); median change (?OHS) was 17 (10 to 41) points. ?OHS was similar in all groupsexcept those patients with solid pseudotumors and those revised to metal-on-metal bearings, who fared worse. Interpretation Planning in revision MOMHA is aided by knowledge of the different categories of failure to enable choice of appropriate personnel, theater time, and equipment. With this knowledge, satisfactory outcomes can be achieved in revision of metal-on-metal hip arthroplasty. PMID:23621810

  10. The Management of the Symptomatic Patient With a Metal-on-Metal Hip Prosthesis.

    PubMed

    Harrington, Kate; Phelan, Emma; Torreggiani, William C; Doody, Orla

    2016-02-01

    Metal-on-metal (MoM) hip implants have gained popularity due to their greater stability and reduction in implant failure compare to metal-on-polyethylene prostheses. However, as well as carrying general risks of hip implantation, risks specifically associated with MoM implants have been well documented in recent years. Conditions such as pseudotumours or aseptic lymphocyte-dominated vasculitis-associated lesions are specific to MoM hip implants. In this review we discuss the typical patient presentation, the investigations that should be performed, the typical findings on various imaging modalities, and the treatment options of symptomatic patients with MoM hip arthroplasties. PMID:26800622

  11. Diagnosis of adverse local tissue reactions following metal-on-metal hip arthroplasty.

    PubMed

    Chalmers, Brian P; Perry, Kevin I; Taunton, Michael J; Mabry, Tad M; Abdel, Matthew P

    2016-03-01

    Metal-on-metal (MOM) bearing surfaces in hip arthroplasty have distinct advantages that led to the increase in popularity in North America in the early 2000s. However, with their increased use, concerns such as local cytotoxicity and hypersensitivity reactions leading to soft tissue damage and cystic mass formation (known collectively as adverse local tissue reactions (ALTR)) became apparent. The clinical presentation of ALTR is highly variable. The diagnosis of ALTR in MOM articulations in hip arthroplasty can be challenging and a combination of clinical presentation, physical examination, implant track record, component positioning, serum metal ion levels, cross-sectional imaging, histopathologic analysis, and consideration of alternative diagnoses are essential. PMID:26816329

  12. Metal-on-Metal Hip Arthroplasty: A Review of Adverse Reactions and Patient Management

    PubMed Central

    Drummond, James; Tran, Phong; Fary, Camdon

    2015-01-01

    Recent alarming joint registry data highlighting increased revision rates has prompted further research into the area of metal-on-metal hip replacements and resurfacings. This review article examines the latest literature on the topic of adverse reactions to metal debris and summarises the most up-to-date guidelines on patient management. Adverse reactions to metal debris can cause significant damage to soft tissue and bone if not diagnosed early. Furthermore, not every patient with an adverse reaction to metal debris will be symptomatic. As such, clinicians must remain vigilant when assessing and investigating these patients in order to detect failing implants and initiate appropriate management. PMID:26132653

  13. Metal-on-metal local tissue reaction is associated with corrosion of the head taper junction.

    PubMed

    Fricka, Kevin B; Ho, Henry; Peace, William J; Engh, Charles A

    2012-09-01

    We evaluated taper corrosion in 36-mm diameter metal-on-metal (MOM) and metal-on-polyethylene (MOP) femoral heads from a single manufacturer retrieved for various reasons. Three reviewers visually graded taper corrosion with a 5-point scale on 19 MOM heads and 14 MOP heads. The MOM group had a higher corrosion score than the MOP group (mean, 3.5 vs 1.9; P < .001). There were 8 MOM heads (42%) and only 1 MOP head (7%) that demonstrated corrosion outside of the taper zone. Metal-on-metal patients revised secondary to adverse local tissue reactions (ALTRs) had greater scores than patients without ALTRs (mean, 4.36 vs 2.38; P < .01). Adverse local tissue reactions MOM patients were also likely to have corrosion outside of the taper junction. The corrosion score increased with implantation time, and at all time intervals, the corrosion score for the MOM group was greater. Because corrosion worsens with time, we are concerned that MOM ALTR failures will increase with longer follow-up. PMID:22554728

  14. Lubrication and friction prediction in metal-on-metal hip implants

    NASA Astrophysics Data System (ADS)

    Wang, F. C.; Brockett, C.; Williams, S.; Udofia, I.; Fisher, J.; Jin, Z. M.

    2008-03-01

    A general methodology of mixed lubrication analysis and friction prediction for a conforming spherical bearing in hip implants was developed, with particular reference to a typical metal-on-metal hip replacement. Experimental measurement of frictional torque for a similar implant was carried out to validate the theoretical prediction. A ball-in-socket configuration was adopted to represent the articulation between the femoral head and the acetabular cup under cyclic operating conditions of representative load and motion. The mixed lubrication model presented in this study was first applied to identify the contact characteristics on the bearing surfaces, consisting of both fluid-film and boundary lubricated regions. The boundary lubricated contact was assumed to occur when the predicted fluid film thickness was less than a typical boundary protein layer absorbed on the bearing surfaces. Subsequently, the friction was predicted from the fluid-film lubricated region with viscous shearing due to both Couette and Poiseuille flows and the boundary protein layer contact region with a constant coefficient of friction. The predicted frictional torque of the typical metal-on-metal hip joint implant was compared with the experimental measurement conducted in a functional hip simulator and a reasonably good agreement was found. The mixed lubrication regime was found to be dominant for the conditions considered. Although the percentage of the boundary lubricated region was quite small, the corresponding contribution to friction was quite large and the resultant friction factor was quite high.

  15. Surface engineering: a low wearing solution for metal-on-metal hip surface replacements.

    PubMed

    Leslie, Ian J; Williams, Sophie; Brown, Chris; Anderson, James; Isaac, Graham; Hatto, Peter; Ingham, Eileen; Fisher, John

    2009-08-01

    Increased patient blood and serum levels of Co and Cr and dissemination of metal wear particles throughout organs and tissues are the primary concerns with metal-on-metal surface replacements. Surface engineering, providing a ceramic bearing surface on a metal substrate, could provide a solution. This study investigated thick (>10 microm) arc evaporation plasma vapor deposition chromium nitride (CrN) coated surface replacements in terms of wear, ion levels, and wear particles in a 10 million cycle hip simulator study, compared to a contemporary metal-on-metal surface replacement. The ion levels were measured by inductively coupled plasma mass spectroscopy. The wear particles were imaged by field emission gun scanning electron microscopy. The CrN-coated bearings had 80% lower wear than the MoM controls. The Cr and Co ion levels in the lubricant of the CrN bearings were 73 and 98% lower than in the MoM controls. The wear particles produced were in the nanometer size range and round to oval in morphology. The CrN coating could provide a reduction in the wear and ion release of MoM surface replacements, thereby reducing the perceived risks to the patient associated with these prostheses. PMID:19195030

  16. Ion release in stable hip arthroplasties using metal-on-metal articulating surfaces: a comparison between short- and medium-term results.

    PubMed

    Savarino, L; Granchi, D; Ciapetti, G; Cenni, E; Greco, M; Rotini, R; Veronesi, C A; Baldini, N; Giunti, A

    2003-09-01

    The use of metallic heads articulating with metallic cups could solve the problem of polyethylene (PE) wear in total hip replacement (THR) with metal-on-PE bearings. A conspicuous release of metal ions from new models of metal-on-metal bearings has been found in the short-term, but it is yet unclear whether the medium-term corrosion rate is high or, on the contrary, it becomes negligible, because of the continuous surface finishing. Our purpose was to compare the serum ion values (nanograms per milliliter) in 15 patients with metal-on-metal stable prosthesis (Group A), in the short-term (subgroup A(1); mean follow-up: 24 mo) and medium-term (subgroup A(2); mean follow-up: 52 mo), in order to determine whether the ion release decreased with time of implant. Chromium (Cr), cobalt (Co), molybdenum (Mo) and aluminum (Al) were analyzed. Twenty-two presurgical patients were used for comparison (Group B). The reference range was obtained from a population of 27 healthy subjects (Group C). Co and Cr levels in the medium-term (subgroup A(2)) were not decreased in comparison with the short-term values (subgroup A(1)) and were significantly higher (p < 0.001) than presurgical and reference values. Otherwise, Mo and Al concentrations were not significantly increased in comparison with reference values. In conclusion, despite the apparent advantage of metal-on-metal coupling, especially in younger patient populations, there is a major concern about the extent and duration of the relevant "internal" exposure to Cr and Co ions. This exposure should be carefully monitored, in order to clarify the biologic effects of ion dissemination and, consequently, to identify risks concerning long-term toxicity of metals. PMID:12918026

  17. Are all metal-on-metal hip revision operations contributing to the National Joint Registry implant survival curves?

    PubMed Central

    Sabah, S. A.; Henckel, J.; Koutsouris, S.; Rajani, R.; Hothi, H.; Skinner, J. A.; Hart, A. J.

    2016-01-01

    Aims The National Joint Registry for England, Wales and Northern Ireland (NJR) has extended its scope to report on hospital, surgeon and implant performance. Data linkage of the NJR to the London Implant Retrieval Centre (LIRC) has previously evaluated data quality for hip primary procedures, but did not assess revision records. Methods We analysed metal-on-metal hip revision procedures performed between 2003 and 2013. A total of 69 929 revision procedures from the NJR and 929 revised pairs of components from the LIRC were included. Results We were able to link 716 (77.1%) revision procedures on the NJR to the LIRC. This meant that 213 (22.9%) revision procedures at the LIRC could not be identified on the NJR. We found that 349 (37.6%) explants at the LIRC completed the full linkage process to both NJR primary and revision databases. Data completion was excellent (> 99.9%) for revision procedures reported to the NJR. Discussion This study has shown that only approximately one third of retrieved components at the LIRC, contributed to survival curves on the NJR. We recommend prospective registry-retrieval linkage as a tool to feedback missing and erroneous data to the NJR and improve data quality. Take home message: Prospective Registry retrieval linkage is a simple tool to evaluate and improve data quality on the NJR. Cite this article: Bone Joint J 2016;98-B:339. PMID:26733513

  18. Formation of molten metal films during metal-on-metal slip under extreme interfacial conditions

    NASA Astrophysics Data System (ADS)

    Liou, Nai-Shang; Okada, Makoto; Prakash, Vikas

    2004-09-01

    The present paper describes results of plate-impact pressure-shear friction experiments conducted to study time-resolved growth of molten metal films during dry metal-on-metal slip under extreme interfacial conditions. By employing tribo-pairs comprising hard tool-steel against relatively low melt-point metals such as 7075-T6 aluminum alloys, interfacial friction stress ranging from 100 to 400 MPa and slip speeds of approximately 100 m/ s have been generated. These relatively high levels of friction stress combined with high slip-speeds generate conditions conducive for interfacial temperatures to approach the melting point of the lower melt point metal (Al alloy) comprising the tribo-pair. A Lagrangian finite element code is developed to understand the evolution of the thermo-mechanical fields and their relationship to the observed slip response. The code accounts for dynamic effects, heat conduction, contact with friction, and full thermo-mechanical coupling. At temperatures below the melting point the material is described as an isotropic thermally softening elastic-viscoplastic solid. For material elements with temperatures in excess of the melt point a purely Newtonian fluid constitutive model is employed. The results of the hybrid experimental-computational study provides new insights into the thermoelastic-plastic interactions during high speed metal-on-metal slip under extreme interfacial conditions. During the early part of frictional slip the coefficient of kinetic friction is observed to decrease with increasing slip velocity. During the later part transition in interfacial slip occurs from dry metal-on-metal sliding to the formation of molten Al films at the tribo-pair interface. Under these conditions the interfacial resistance approaches the shear strength of the molten aluminum alloy under normal pressures of approximately 1- 3 GPa and shear strain rates of 10 7 s-1. The results of the study indicate that under these extreme conditions molten aluminum films maintain a shearing resistance as high as 100 MPa. Scanning electron microscopy of the slip surfaces reveal molten aluminum to be smeared on the tribo-pair interface. Knoop hardness measurements in 7075-T6 Al alloy at various depths from the slip interface indicate that the hardness increases approximately linearly with depth and reaches a plateau at approximately 40 ?m from the surface.

  19. Perivascular Lymphocytic Infiltration Is Not Limited to Metal-on-Metal Bearings

    PubMed Central

    Ng, Vincent Y.; Berend, Keith R.; Skeels, Michael D.; Adams, Joanne B.

    2010-01-01

    Background Perivascular lymphocytic infiltration (PVLI) suggests an adaptive immune response. Metal hypersensitivity after THA is presumed associated with idiopathic pain and aseptic loosening, but its incidence and relationship to metallic wear leading to revision are unclear as are its presence and relevance in non-metal-on-metal arthroplasty. Questions/purposes We compared (1) incidence and severity of PVLI in failed hip metal-on-metal (MoM) to non-MoM implants and TKA; (2) PVLI in MoM and non-MoM hip arthroplasty based on reason for revision; and (3) PVLI grade to diffuse lymphocytic infiltration (DLI) and tissue reaction to metal particles. Patients and Methods We retrospectively examined incidence and severity of PVLI, DLI, and tissue reaction in periprosthetic tissue from 215 THA and 242 TKA revisions including 32 MoM hips. Results Perivascular lymphocytic infiltration was present in more TKAs (40%) than overall hip arthroplasties (24%) without difference in severity. Compared to non-MoM hips, MoM bearings were more commonly associated with PVLI (59% versus 18%) and demonstrated increased severity (41% versus 3% greater than mild). Histologically, PVLI correlated (r=0.51) with DLI, but not tissue reaction. In THA, PVLI was most commonly associated with idiopathic pain (70%) and aseptic loosening (54%) in MoM, and infection in all hip revisions (53%). Conclusions Perivascular lymphocytic infiltration is more extensive in revisions of MoM and in aseptic loosening, idiopathic pain, or infection but is also present in TKA, non-MoM, and different reasons for revision. It correlates with other signs of metal hypersensitivity, but not with histologic measures of metal particulate load. Level of Evidence Level III, diagnostic study. See the Guidelines for Authors for a complete description of levels of evidence. PMID:20878289

  20. Novel method for characterization and compensation for canopy distortion over a large head box

    NASA Astrophysics Data System (ADS)

    Atac, Robert; Fischler, Mark

    2013-05-01

    Thales Visionix, a wholly owned subsidiary of Thales Communications, Inc., has developed a novel method for characterization of canopy distortion for a large head box. Canopy distortion occurs when the user is looking through any curved transparency. Any helmet mounted display system must either compensate for this distortion, or add canopy distortion error to its total error budget. To date, canopies have been characterized for only a few discrete locations in the cockpit. This results in a dilution of canopy distortion compensation as the pilot will rarely sit in one of the few defined locations. The method described herein allows for canopy distortion characterization and compensation for the entire HMD head-box.

  1. Effects of CoCr metal wear debris generated from metal-on-metal hip implants and Co ions on human monocyte-like U937 cells.

    PubMed

    Posada, Olga M; Tate, Rothwelle J; Grant, M Helen

    2015-03-01

    Hip resurfacing with cobalt-chromium (CoCr) alloy was developed as a surgical alternative to total hip replacement. However, the biological effects of nanoparticles generated by wear at the metal-on-metal articulating surfaces has limited the success of such implants. The aim of this study was to investigate the effects of the combined exposure to CoCr nanoparticles and cobalt ions released from a resurfacing implant on monocytes (U937 cells) and whether these resulted in morphology changes, proliferation alterations, toxicity and cytokine release. The interaction between prior exposure to Co ions and the cellular response to nanoparticulate debris was determined to simulate the situation in patients with metal-on-metal implants receiving a second implant. Effects on U937 cells were mainly seen after 120h of treatment. Prior exposure to Co ions increased the toxic effects induced by the debris, and by Co ions themselves, suggesting the potential for interaction in vivo. Increased TNF-? secretion by resting cells exposed to nanoparticles could contribute to osteolysis processes in vivo, while increased IFN-? production by activated cells could represent cellular protection against tissue damage. Data suggest that interactions between Co ions and CoCr nanoparticles would occur in vivo, and could threaten the survival of a CoCr metal implant. PMID:25433333

  2. Fast growing pseudotumour in a hairdresser after metal-on-metal hip resurfacing: a case report.

    PubMed

    Cadossi, M; Chiarello, E; Savarino, L; Mazzotti, A; Tedesco, G; Greco, M; Giannini, S

    2014-01-01

    A 44-year-old female hairdresser who underwent metal-on-metal hip resurfacing (MOMHR) for hip osteoarthritis developed a benign pelvic pseudotumour. Elevated levels of chromium and cobalt ions were detected in the blood. Patch testing after pseudotumor formation, showed positive skin reactions to cobalt and nickel. Marked hypereosinophilia was noted, as well as the presence of eosinophils in the pseudotumor mass. A revision to a ceramic-on-ceramic implant was performed. Radiographs showed no implant loosening or bone resorption. We hypothesized that a steep cup positioning as well as hypersensitivity response to the metal nanoparticles and ion release may have induced pseudotumour development. Currently there is no evidence that negative patch testing reduces the probability to develop an adverse reaction to metal debris therefore we suggest to carefully investigate patient medical history regarding occupation exposure and daily contact with jewellery, beauty and cleaning products before implanting MOMHR. The main challenge is to identify a sensitive patient candidate to MOMHR never suspected to be. PMID:24825038

  3. The medical ecoculture at work: the case of the metal-on-metal hip.

    PubMed

    Gillick, Muriel R

    2013-01-01

    The United States has the most expensive, technologically intensive system of medical care in the world, but not the most effective. Reforming health care will require understanding the interactions among the many individuals and institutions that collectively constitute the health-care ecoculture, an ecosystem with a major human component. Because technology is a key driver of health-care costs and a critical component of the patient's experience of American medicine, it is fruitful to consider an example of a particular technology: why it was embraced, who benefited from its use, and the response of the ecoculture when a critical flaw in the technology emerged. The case of the introduction, diffusion, and withdrawal of metal-on-metal hip prostheses will be discussed from the perspective of patients, physicians, device manufacturers, regulators, and the legal system. Each of these groups responded to external stimuli by adaptation in an attempt to maximize its own interests. Interactions between the groups served as a further mechanism of maintaining the status quo within medicine. A single change, such as modification of the payment system or incentivizing patients, is thus unlikely to be effective in transforming health care; instead, a multi-pronged approach, along with reforms outside medicine, will likely be necessary. PMID:24769749

  4. A lexicon for wear of metal-on-metal hip prostheses.

    PubMed

    McKellop, Harry A; Hart, Alister; Park, Sang-Hyun; Hothi, Harry; Campbell, Pat; Skinner, John A

    2014-09-01

    Research on metal-on-metal (MoM) hip bearings has generated an extensive vocabulary to describe the wear processes and resultant surface damage. However, a lack of consistency and some redundancy exist in the current terminology. To facilitate the understanding of MoM tribology and to enhance communication of results among researchers and clinicians, we propose four categories of wear terminology: wear modes refer to the in vivo conditions under which the wear occurred; wear mechanisms refer to fundamental wear processes (adhesion, abrasion, fatigue, and tribochemical reactions); wear damage refers to the resultant changes in the morphology and/or composition of the surfaces; and wear features refer to the specific wear phenomena that are described in terms of the relevant modes, mechanisms, and damage. Clarifying examples are presented, but it is expected that terms will be added to the lexicon as new mechanisms and types of damage are identified. Corrosion refers to electrochemical processes that can remove or add material and thus also generate damage. Corrosion can act alone or may interact with mechanical wear. Examples of corrosion damage are also presented. However, an in-depth discussion of the many types of corrosion and their effects is beyond the scope of the present wear lexicon. PMID:24844814

  5. Prevalence of Pseudotumor in Patients After Metal-On-Metal Hip Arthroplasty Evaluated with Metal Ion Analysis and MARS-MRI.

    PubMed

    Sutphen, Sean A; MacLaughlin, Lewis H; Madsen, Adam A; Russell, Jackie H; McShane, Michael A

    2016-01-01

    The purpose of this study is to quantify the prevalence of pseudotumors in patients with well-functioning and painful metal-on-metal total hip arthroplasty, to characterize the pseudotumor with the use of MARS-MRI, and to assess the relationship between pseudotumors and metal ions. We retrospectively reviewed 102 single surgeon patients. The results showed that 68.6% developed pseudotumor with 60.9% of the asymptomatic group developing pseudotumor. The symptomatic group had a higher proportion of patients with elevated serum cobalt levels (P=0.035). There was no difference found with elevated metal ions and prevalence of pseudotumor, but elevated cobalt levels were associated with larger pseudotumor size (P=0.001). The available evidence indicated that most patients that develop pseudotumors are asymptomatic, and that elevated serum cobalt levels may be associated with symptoms and pseudotumor size. PMID:26253484

  6. Changes in blood ion levels after removal of metal-on-metal hip replacements

    PubMed Central

    Durrani, Salim K; Sampson, Barry; Panetta, Therese; Liddle, Alexander D; Sabah, Shiraz A; Chan, Newton K; Skinner, John A; Hart, Alister J

    2014-01-01

    Background and purpose In patients with metal-on-metal (MoM) hip prostheses, pain and joint effusions may be associated with elevated blood levels of cobalt and chromium ions. Since little is known about the kinetics of metal ion clearance from the body and the rate of resolution of elevated blood ion levels, we examined the time course of cobalt and chromium ion levels after revision of MoM hip replacements. Patients and methods We included 16 patients (13 female) who underwent revision of a painful MoM hip (large diameter, modern bearing) without fracture or infection, and who had a minimum of 4 blood metal ion measurements over an average period of 6.1 (012) months after revision. Results Average blood ion concentrations at the time of revision were 22 ppb for chromium and 43 ppb for cobalt. The change in ion levels after revision surgery varied extensively between patients. In many cases, over the second and third months after revision surgery ion levels decreased to 50% of the values measured at revision. Decay of chromium levels occurred more slowly than decay of cobalt levels, with a 9% lag in return to normal levels. The rate of decay of both metals followed second-order (exponential) kinetics more closely than first-order (linear) kinetics. Interpretation The elimination of cobalt and chromium from the blood of patients who have undergone revision of painful MoM hip arthroplasties follows an exponential decay curve with a half-life of approximately 50 days. Elevated blood levels of cobalt and chromium ions can persist for at least 1 year after revision, especially in patients with high levels of exposure. PMID:24758321

  7. Cross-sectional imaging of metal-on-metal hip arthroplasties

    PubMed Central

    Robinson, Elizabeth; Henckel, Johann; Sabah, Shiraz; Satchithananda, Keshthra; Skinner, John; Hart, Alister

    2014-01-01

    Background and purpose Metal artifact reduction sequence (MARS) MRI is widely advocated for surveillance of metal-on-metal hip arthroplasties (MOM-HAs). However, its use is limited by susceptibility artifact at the prosthesis-bone interface, local availability, patient compliance, and cost (Hayter et al. 2011a). We wanted to determine whether CT is a suitable substitute for MARS MRI in evaluation of the painful MOM-HA. Patients and methods 50 MOM-HA patients (30 female) with unexplained painful prostheses underwent MARS MRI and CT imaging. 2 observers who were blind regarding the clinical data objectively reported the following outcomes: soft tissue lesions (pseudotumors), muscle atrophy, and acetabular and femoral osteolysis. Diagnostic test characteristics were calculated. Results Pseudotumor was diagnosed in 25 of 50 hips by MARS MRI and in 11 of 50 by CT. Pseudotumors were classified as type 1 (n = 2), type 2A (n = 17), type 2B (n = 4), and type 3 (n = 2) by MARS MRI. CT did not permit pseudotumor classification. The sensitivity of CT for diagnosis of pseudotumor was 44% (95% CI: 2565). CT had slight agreement with MARS MRI for quantification of muscle atrophy (? = 0.23, CI: 0.160.29; p < 0.01). Osteolysis was identified in 15 of 50 patients by CT. 4 of these lesions were identified by MARS MRI. Interpretation CT was found to be superior to MRI for detection of osteolysis adjacent to MOM-HA, and should be incorporated into diagnostic algorithms. CT was unable to classify and failed to detect many pseudotumors, and it was unreliable for assessment of muscle atrophy. Where MARS MRI is contraindicated or unavailable, CT would be an unsuitable substitute and other modalities such as ultrasound should be considered PMID:25267500

  8. Microfocus study of metal distribution and speciation in tissue extracted from revised metal on metal hip implants

    NASA Astrophysics Data System (ADS)

    Hart, Alister J.; Sandison, Ann; Quinn, Paul; Sampson, Barry; Atkinson, Kirk D.; Skinner, John A.; Goode, Angela; Powell, Jonathan J.; Mosselmans, J. Frederick W.

    2009-11-01

    Unexplained tissue inflammation in metal-on-metal hip replacements is suspected to be caused by implant-derived nanoparticles. The aim of this study was to investigate the nature of the metal particles in tissue surrounding metal-on-metal (MOM) hips that has been extracted during revision. Mapping of tissue surrounding the failed MOM hips was performed using microfocus X-ray Fluorescence (XRF). This revealed mainly Cr which was localized to the cellular regions. There was co-localisation of Co, were present, to areas of high Cr abundance. XANES of the tissue and appropriate standards revealed that the most common species were Cr(III) and Co(II). EXAFS analysis of the tissue and various metal standards revealed that the most abundant implant-related species was Cr(III) phosphate. Different tissue preparation methods, including frozen sectioning, were examined but were found not to affect the distribution or speciation of the metals in the tissue.

  9. Validation of primary metal-on-metal hip arthroplasties on the National Joint Registry for England, Wales and Northern Ireland using data from the London Implant Retrieval Centre

    PubMed Central

    Sabah, S. A.; Henckel, J.; Cook, E.; Whittaker, R.; Hothi, H.; Pappas, Y.; Blunn, G.; Skinner, J. A.; Hart, A. J.

    2015-01-01

    Arthroplasty registries are important for the surveillance of joint replacements and the evaluation of outcome. Independent validation of registry data ensures high quality. The ability for orthopaedic implant retrieval centres to validate registry data is not known. We analysed data from the National Joint Registry for England, Wales and Northern Ireland (NJR) for primary metal-on-metal hip arthroplasties performed between 2003 and 2013. Records were linked to the London Implant Retrieval Centre (RC) for validation. A total of 67045 procedures on the NJR and 782 revised pairs of components from the RC were included. We were able to link 476 procedures (60.9%) recorded with the RC to the NJR successfully. However, 306 procedures (39.1%) could not be linked. The outcome recorded by the NJR (as either revised, unrevised or death) for a primary procedure was incorrect in 79 linked cases (16.6%). The rate of registry-retrieval linkage and correct assignment of outcome code improved over time. The rates of error for component reference numbers on the NJR were as follows: femoral head category number 14/229 (5.0%); femoral head batch number 13/232 (5.3%); acetabular component category number 2/293 (0.7%) and acetabular component batch number 24/347 (6.5%). Registry-retrieval linkage provided a novel means for the validation of data, particularly for component fields. This study suggests that NJR reports may underestimate rates of revision for many types of metal-on-metal hip replacement. This is topical given the increasing scope for NJR data. We recommend a system for continuous independent evaluation of the quality and validity of NJR data. Cite this article: Bone Joint J 2015;97-B:1018. PMID:25568407

  10. Longitudinal evaluation of time related femoral neck narrowing after metal-on-metal hip resurfacing

    PubMed Central

    Wang, Wenbao; Geller, Jeffrey A; Hasija, Rohit; Choi, Jung Keun; Patrick, David A Jr.; Macaulay, William

    2013-01-01

    AIM: To track the short-term neck narrowing changes in Birmingham metal-on-metal hip resurfacing (MOMHR) patients. METHODS: Since 2001, the Center for Hip and Knee Replacement started a registry to prospectively collect data on hip and knee replacement patients. From June 2006 to October 2008, 139 MOMHR were performed at our center by two participate surgeons using Birmingham MOMHR prosthesis (Smith Nephew, United States). It is standard of care for patients to obtain low, anteriorposterior (LAP) pelvis radiographs immediately after MOMHR procedure and then at 3 mo, 1 year and 2 year follow up office visits. Inclusion criteria for the present study included patients who came back for follow up office visit at above mentioned time points and got LAP radiographs. Exclusion criteria include patients who missed more than two follow up time points and those with poor-quality X-rays. Two orthopaedic residency trained research fellows reviewed the X-rays independently at 4 time points, i.e., immediate after surgery, 3 mo, 1 year and 2 year. Neck-to-prosthesis ratio (NPR) was used as main outcome measure. Twenty cases were used as subjects to identify the reliability between two observers. An intraclass correlation coefficient at 0.8 was considered as satisfied. A paired t-test was used to evaluate the significant difference between different time points with P < 0.05 considered to be statistically significant. RESULTS: The mean NPRs were 0.852 ± 0.056, 0.839 ± 0.052, 0.835 ± 0.051, 0.83 ± 0.04 immediately, 3 mo, 1 year and 2 years post-operatively respectively. At 3 mo, NPR was significantly different from immediate postoperative X-ray (P < 0.001). There was no difference between 3 mo and 1 year (P = 0.14) and 2 years (P = 0.53). Femoral neck narrowing (FNN) exceeding 10% of the diameter of the neck was observed in only 4 patients (5.6%) at two years follow up. None of these patients developed a femoral neck fracture (FNF). CONCLUSION: Femoral neck narrowing after MOMHR occurred as early as 3 mo postoperatively, and stabilized thereafter. Excessive FNN was not common in patients within the first two years of surgery and was not correlated with risk of FNF. PMID:23610755

  11. Blood metal ion testing is an effective screening tool to identify poorly performing metal-on-metal bearing surfaces

    PubMed Central

    Sidaginamale, R. P.; Joyce, T. J.; Lord, J. K.; Jefferson, R.; Blain, P. G.; Nargol, A. V. F.; Langton, D. J.

    2013-01-01

    Objectives The aims of this piece of work were to: 1) record the background concentrations of blood chromium (Cr) and cobalt (Co) concentrations in a large group of subjects; 2) to compare blood/serum Cr and Co concentrations with retrieved metal-on-metal (MoM) hip resurfacings; 3) to examine the distribution of Co and Cr in the serum and whole blood of patients with MoM hip arthroplasties; and 4) to further understand the partitioning of metal ions between the serum and whole blood fractions. Methods A total of 3042 blood samples donated to the local transfusion centre were analysed to record Co and Cr concentrations. Also, 91 hip resurfacing devices from patients who had given pre-revision blood/serum samples for metal ion analysis underwent volumetric wear assessment using a coordinate measuring machine. Linear regression analysis was carried out and receiver operating characteristic curves were constructed to assess the reliability of metal ions to identify abnormally wearing implants. The relationship between serum and whole blood concentrations of Cr and Co in 1048 patients was analysed using Bland-Altman charts. This relationship was further investigated in an in vitro study during which human blood was spiked with trivalent and hexavalent Cr, the serum then separated and the fractions analysed. Results Only one patient in the transfusion group was found to have a blood Co > 2 g/l. Blood/Serum Cr and Co concentrations were reliable indicators of abnormal wear. Blood Co appeared to be the most useful clinical test, with a concentration of 4.5 g/l showing sensitivity and specificity for the detection of abnormal wear of 94% and 95%, respectively. Generated metal ions tended to fill the serum compartment preferentially in vivo and this was replicated in the in vitro study when blood was spiked with trivalent Cr and bivalent Co. Conclusions Blood/serum metal ion concentrations are reliable indicators of abnormal wear processes. Important differences exist however between elements and the blood fraction under study. Future guidelines must take these differences into account. PMID:23836464

  12. Metal ion release from bearing wear and corrosion with 28 mm and large-diameter metal-on-metal bearing articulations: a follow-up study.

    PubMed

    Vendittoli, P-A; Roy, A; Mottard, S; Girard, J; Lusignan, D; Lavigne, M

    2010-01-01

    We have updated our previous randomised controlled trial comparing release of chromium (Cr) and cobalt (Co) ions and included levels of titanium (Ti) ions. We have compared the findings from 28 mm metal-on-metal total hip replacement, performed using titanium CLS/Spotorno femoral components and titanium AlloFit acetabular components with Metasul bearings, with Durom hip resurfacing using a Metasul articulation or bearing and a titanium plasma-sprayed coating for fixation of the acetabular component. Although significantly higher blood ion levels of Cr and Co were observed at three months in the resurfaced group than in total hip replacement, no significant difference was found at two years post-operatively for Cr, 1.58 microg/L and 1.62 microg/L respectively (p = 0.819) and for Co, 0.67 microg/L and 0.94 microg/L respectively (p = 0.207). A steady state was reached at one year in the resurfaced group and after three months in the total hip replacement group. Interestingly, Ti, which is not part of the bearing surfaces with its release resulting from metal corrosion, had significantly elevated ion levels after implantation in both groups. The hip resurfacing group had significantly higher Ti levels than the total hip replacement group for all periods of follow-up. At two years the mean blood levels of Ti ions were 1.87 microg/L in hip resurfacing and and 1.30 microg/L in total hip replacement (p = 0.001). The study confirms even with different bearing diameters and clearances, hip replacement and 28 mm metal-on-metal total hip replacement produced similar Cr and Co metal ion levels in this randomised controlled trial study design, but apart from wear on bearing surfaces, passive corrosion of exposed metallic surfaces is a factor which influences ion concentrations. Ti plasma spray coating the acetabular components for hip resurfacing produces significantly higher release of Ti than Ti grit-blasted surfaces in total hip replacement. PMID:20044673

  13. Meeting the demands of on-going metal-on-metal hip surveillance through nurse led services.

    PubMed

    Elliott, Sue; Langfield, Sarah

    2016-02-01

    This paper discusses the implications following a recall of all metal-on-metal hip replacements by the Medicines and Healthcare products regulatory Agency (MHRA). Issues identified were the release of metal ions from the metal implants. These ions were found to seep into local tissues and cause reactions that destroyed muscle and bone leaving some patients with long term disability. At the centre surveillance was monitored by an extension of the current Nurse Led services using existing staff and resources. There were a significant number of patients that required monitoring and there were difficulties contacting these patients and ensuring that they understood the importance of attending a clinic. PMID:26772766

  14. Clinical Usefulness of SPECT-CT in Patients with an Unexplained Pain in Metal on Metal (MOM) Total Hip Arthroplasty.

    PubMed

    Berber, Reshid; Henckel, Johann; Khoo, Michael; Wan, Simon; Hua, Jia; Skinner, John; Hart, Alister

    2015-04-01

    SPECT-CT is increasingly used to assess painful knee arthroplasties. The aim of this study was to evaluate the clinical usefulness of SPECT-CT in unexplained painful MOM hip arthroplasty. We compared the diagnosis and management plan for 19 prosthetic MOM hips in 15 subjects with unexplained pain before and after SPECT-CT. SPECT-CT changed the management decision in 13 (68%) subjects, Chi-Square=5.49, P=0.24. In 6 subjects (32%) pain remained unexplained however the result reassured the surgeon to continue with non-operative management. SPECT-CT should be reserved as a specialist test to help identify possible causes of pain where conventional investigations have failed. It can help reassure surgeons making management decisions for patients with unexplained pain following MOM hip arthroplasty. PMID:25583682

  15. Is Increased Modularity Associated With Increased Fretting and Corrosion Damage in Metal-On-Metal Total Hip Arthroplasty Devices?

    PubMed Central

    Higgs, Genymphas B.; Hanzlik, Josa A.; MacDonald, Daniel W.; Gilbert, Jeremy L.; Rimnac, Clare M.; Kurtz, Steven M.

    2014-01-01

    This retrieval study documents taper damage at modular interfaces in retrieved MOM THA systems and investigates if increased modularity is associated with increased fretting and corrosion. One hundred thirty-four (134) heads and 60 stems (41 modular necks) of 8 different bearing designs (5 manufacturers) were analyzed. Damage at the shellliner interface of 18 modular CoCr acetabular liners and the corresponding 11 acetabular shells was also evaluated. The results of this study support the hypothesis that fretting and corrosion damage occurs at a variety of modular component interfaces in contemporary MOM THAs. We also found that modularity of the femoral stem was associated with increased damage at the head. An analysis of component and patient variables revealed that dissimilar alloy pairing, larger head sizes, increased medio-lateral offsets and longer neck moment arms were all associated with increased taper damage at the modular interfaces. PMID:23910820

  16. Combined Vascular and Orthopaedic Approach for a Pseudotumor Causing Deep Vein Thrombosis after Metal-on-Metal Hip Resurfacing Arthroplasty

    PubMed Central

    Abdel-Hamid, Hossam; Miles, Jonathan; Carrington, Richard W. J.; Hart, Alister; Loh, Alex; Skinner, John A.

    2015-01-01

    Introduction. Metal-on-metal (MoM) hip resurfacings have been associated with a variety of complications resulting from adverse reaction to metal debris. Pseudotumors have rarely been reported to cause deep venous thrombosis (DVT). Study Design. A case report and a review of the literature. Case Presentation. A 75-year-old female who had left metal-on-metal hip resurfacing 6 years ago presented with left groin pain associated with unilateral lower limb edema and swelling. By duplex and MRI studies, our patient had an extensive soft tissue necrosis associated with a large pelvic mass causing extensive DVT of the lower limb secondary to mechanical compression of the left iliac vein. Results. Our case was initially treated for DVT followed by dual surgical approach. The pseudotumor was excised through a separate iliofemoral approach and revision of the hip implant was undertaken through a posterior approach in the same setting. An inferior vena cava (IVC) filter was inserted to minimise the perioperative risks of handling the iliac veins. Conclusion. A combined approach with vascular surgeons is required. Combined resection of the pseudotumor and revision of the metal bearing surfaces is essential, in order to achieve a good surgical outcome in this rare complication. PMID:26457216

  17. Lessons learnt from metal-on-metal hip arthroplasties will lead to safer innovation for all medical devices.

    PubMed

    Hart, Alister J; Sabah, Shiraz A; Henckel, Johann; Lloyd, Gwynneth; Skinner, John A

    2015-01-01

    Metal-on-metal bearings were re-popularised in the late 1990s with the introduction of modern hip resurfacing. Large diameter (LD) metal-on-metal (MoM) hips became more prevalent and have been the least successful group of hip implants ever used. They were rapidly adopted from 2004 until the British Hip Society stopped their use in 2012. Well functioning MoM hip results (including the BHR and Metasul) are hidden in the mire of poor results from the group of all MoM bearings.We have reviewed what happened and we make 3 observations. Firstly, collaboration between surgeons and then between surgeons and other disciplines, first identified and then solved the clinical management problems. Secondly, the problems with MoM hips occurred because hip simulation was inadequate at predicting performance in patients. They gave no indications of the biological effects of wear in the human environment. Lastly, retrieval of failed implants was essential to understanding why failure occurred.These lessons must never be forgotten and must form the basis by which new or altered implants are introduced and how they should be monitored. This will enable safer innovation for patients, surgeons and manufacturers. The problems with MoM hips will not have been in vain. PMID:26165359

  18. Chromium-induced diffuse dermatitis with lymph node involvement resulting from Langerhans cell histiocytosis after metal-on-metal hip resurfacing.

    PubMed

    Bizzotto, N; Sandri, A; Trivellin, G; Magnan, B; Micheloni, G M; Zam, A; Bernardi, P; Sbarbati, A; Regis, D

    2015-06-01

    Total hip arthroplasty (THA) is a highly effective surgical treatment for severe joint involvement. However, due to the release of metal ions in the blood, the patients who undergo hip replacement with metal-on-metal (MOM) bearings may develop signs of allergic skin disease. We report a case of a 60-year-old man who had received MOM hip resurfacing 5years earlier for osteoarthritis. He presented with a 3-year history of diffuse dermatitis that did not respond to antihistamines and corticosteroids and also had elevated serum levels of chromium and cobalt. A patch test revealed chromium-sulfate hypersensitivity. A skin biopsy showed nonspecific perivascular lymphocytic infiltrate associated with histiocytes. A biopsy of an inguinal lymph node demonstrated large aggregates of Langerhans cells, suggesting type IV delayed-type hypersensitivity. The prosthesis was replaced using ceramic-on-ceramic bearings and the dermatitis resolved after 3months. The lymph nodes decreased in volume and the serum chromium levels normalized within 24months of revision surgery. The high levels of serum ions associated with the metal debris from MOM-THAs may induce sensitization and type IV hypersensitivity reactions. Replacing the prosthesis using alternative coupling surfaces is the only approach that has the capacity to resolve these symptoms. Physicians who are not familiar with this issue may misdiagnose systemic symptoms and provide inadequate treatment. PMID:25385406

  19. Effect of head size on wear properties of metal-on-metal bearings of hip prostheses, and comparison with wear properties of metal-on-polyethylene bearings using hip simulator.

    PubMed

    Okazaki, Yoshimitsu

    2014-03-01

    The effects of articular head size on the wear losses of the metal insert and articular head for a metal-on-metal bearing were examined using a hip simulator manufactured to satisfy ISO 14242-1. The wear properties of metal-on-metal and metal-on-polyethylene bearings were also compared under the same conditions. The total wear losses of the metal insert and articular head decreased with increasing diameter of the metal insert in the range from 28 to 44mm. The total wear loss was greater for a diameter of 48mm than for a diameter of 44mm. When the articular metal insert diameter was smaller than 44mm, the wear loss was reduced because the contact surface pressure increased with increasing metal insert diameter. However, the increase in wear loss observed for the 48-mm-diameter insert might have been due to the considerable increase in the rotation moment with increasing insert diameter. The tendency of decreasing contact pressure calculated using the Hertzian contact stress equation nearly conformed to the change in wear loss. On the other hand, the wear loss of an artificial hip joint consisting of a cross-linked ultrahigh-molecular-weight polyethylene insert (UHMWPE) and a Co-Cr-Mo articular head was small. PMID:24290355

  20. How Should We Follow-Up Asymptomatic Metal-on-Metal Hip Resurfacing Patients? A Prospective Longitudinal Cohort Study.

    PubMed

    Low, Adrian K; Matharu, Gulraj S; Ostlere, Simon J; Murray, David W; Pandit, Hemant G

    2016-01-01

    Current surveillance for metal-on-metal hip resurfacing (MoMHR) patients is not evidence based. This study established changes that occurred in 152 asymptomatic MoMHRs using repeat ultrasound and patient-reported outcomes. Factors associated with (1) ultrasound progression and (2) developing new pseudotumors were analyzed. Patients underwent repeat assessments 4.3 years later. Ultrasound progression was observed in 19% (n = 29), with 10% (n = 15) developing new pseudotumors. Key predictors of ultrasound progression included high blood cobalt (P = .00013) and chromium (P = .00065), and high initial ultrasound grade (P = .003) and volume (P = .036). No asymptomatic MoMHRs with initially normal metal ions (<2 ?g/L) and normal ultrasounds (33% of cohort) developed new pseudotumors. This patient subgroup does not require repeat follow-up within 5 years. PMID:26439179

  1. MRI findings following metal on metal hip arthroplasty and their relationship with metal ion levels and acetabular inclination angles.

    PubMed

    Fox, Ciara M; Bergin, Karen M; Kelly, Gabrielle E; McCoy, Gerry F; Ryan, Anthony G; Quinlan, John F

    2014-08-01

    Following the global recall of all ASR metal on metal hip products, our aim was to correlate MRI findings with acetabular inclination angles and metal ion levels in patients with these implants. Both cobalt and chromium levels were significantly higher in the presence of a periprosthetic fluid collection. There was no association between the presence of a periprosthetic mass, bone marrow oedema, trochanteric bursitis or greater levels of abductor muscle destruction for cobalt or chromium. There was no association between the level of periprosthetic tissue reaction and the acetabular inclination angle with any of the pathologies identified on MRI. The relationship between MRI pathology, metal ion levels and acetabular inclination angles in patients with ASR implants remains unclear adding to the complexity of managing patients. PMID:24793890

  2. Wear of surface-engineered metal-on-metal bearings for hip prostheses under adverse conditions with the head loading on the rim of the cup.

    PubMed

    Leslie, Ian; Williams, Sophie; Isaac, Graham; Hatto, Peter; Ingham, Eileen; Fisher, John

    2013-04-01

    Clinical studies have found high wear rates, elevated ion levels and high revision rates of large-diameter metal-on-metal surface replacement bearings in some patients, which have been associated with edge loading of the head on the rim of the cup. We have simulated increased wear and ion levels in metal-on-metal bearings in vitro by introducing variations in translational and rotational positioning of the components, which reproduces stripe wear on the femoral head, cup rim wear and clinically relevant large as well as small wear particles. There is interest in technologies such as surface engineering, which might reduce metal wear and the release of wear particles and ions. Reduced wear with surface-engineered surface replacements compared to metal-on-metal controls has been reported under standard walking conditions with correctly aligned and concentric components. In this in vitro study, the wear of chromium nitride surface-engineered metal-on-metal bearings under conditions of microseparation associated with translational and rotational malpositioning of the components was investigated and the results were compared with a previously reported study of metal-on-metal bearings under the same conditions. Simulations were conducted using our unique hip simulation microseparation methodologies, which reproduce accelerated wear in metal-on-metal bearings and have previously been clinically validated with ceramic-on-ceramic bearings. Four of the six surface-engineered bearings had evidence of head contact on the rim of the cup, which produced stripe wear on the femoral head. Four of the six surface-engineered bearings (two without stripe and two with stripe wear) had lower wear than the previously reported high wearing metal-on-metal bearings. At 2 million cycles, two of the surface-engineered bearings had substantially increased wear rates, four times higher than the high wear rates previously reported for metal-on-metal bearings under the same conditions. There was wear through and cohesive failure of the thick atomic emission physical vapour deposition (AEPVD) chromium nitride (CrN) coating. At this point, the study was stopped to investigate the failure mode. This study highlights the need to pre-clinically investigate the tribology of new bearings under a wide set of clinical conditions as demonstrated by our stratified approach for enhanced reliability (SAFER) simulation methods. In adopting this SAFER approach to pre-clinical simulation testing of new bearings, it is important to communicate the failures as well as successes of technologies arising from the research, in order that the wider community can benefit from the analysis of the pre-clinical failure modes. PMID:23637209

  3. Early failure of the Durom prosthesis in metal-on-metal hip resurfacing in Chinese patients.

    PubMed

    Li, Jia; He, Chongru; Li, Dahe; Zheng, Wei; Liu, Denghui; Xu, Weidong

    2013-12-01

    Hip resurfacing (HR) is being used increasingly as an alterative to total hip arthroplasty in osteonecrosis (ON) and ankylosing spondylitis (AS) of the hip. We performed 141 consecutive HR arthroplasties in 111 patients comprising 3 etiology groups: ON, AS, and osteoarthritis (OA). After retrospective study of retrieved components, we hypothesized that the main reason for revision was femoral loosening in the ON group (4 of 46 hips; 8.7%) and femoral-neck fracture in the AS group (3 of 58 hips; 5.2%). Necrotic areas were seen on femoral heads retrieved from patients with femoral loosening, whereas femoral heads were fixed tightly to components in patients with femoral-neck fractures. Etiology may be an important risk factor for postoperative complications. PMID:23831082

  4. Comparison of in vivo and simulator-retrieved metal-on-metal cervical disc replacements

    PubMed Central

    Kurtz, Steven M.; Ciccarelli, Lauren; Harper, Megan L.; Siskey, Ryan; Shorez, Jacob; Chan, Frank W.

    2012-01-01

    Background Cervical disc arthroplasty is regarded as a promising treatment for myelopathy and radiculopathy as an alternative to cervical spine fusion. On the basis of 2-year clinical data for the PRESTIGE Cervical Disc (Medtronic, Memphis, Tennessee), the Food and Drug Administration recommended conditional approval in September 2006 and final approval in July 2007; however, relatively little is known about its wear and damage modes in vivo. The main objective was to analyze the tribological findings of the PRESTIGE Cervical Disc. This study characterized the in vivo wear patterns of retrieved cervical discs and tested the hypothesis that the total disc replacements exhibited similar surface morphology and wear patterns in vitro as in vivo. Methods Ten explanted total disc replacements (PRESTIGE, PRESTIGE I, and PRESTIGE II) from 10 patients retrieved after a mean of 1.8 years (range, 0.34.1 years) were analyzed. Wear testing included coupled lateral bending ( 4.7) and axial rotation ( 3.8) with a 49 N axial load for 5 million cycles followed by 10 million cycles of flexion-extension ( 9.7) with 148 N. Implant surfaces were characterized by the use of white-light interferometry, scanning electron microscopy, and energy dispersive spectroscopy. Results The explants generally exhibited a slightly discolored, elliptic wear region of varying dimension centered in the bearing center, with the long axis oriented in the medial-lateral direction. Abrasive wear was the dominant in vivo wear mechanism, with microscopic scratches generally oriented in the medial-lateral direction. Wear testing resulted in severe abrasive wear in a curvilinear fashion oriented primarily in the medial-lateral direction. All retrievals showed evidence of an abrasive wear mechanism. Conclusions This study documented important similarity between the wear mechanisms of components tested in vitro and explanted PRESTIGE Cervical Discs; however, the severity of wear was much greater during the in vitro test compared with the retrievals. PMID:25694884

  5. Gluteal muscle fatty atrophy is not associated with elevated blood metal ions or pseudotumors in patients with a unilateral metal-on-metal hip replacement.

    PubMed

    Reito, Aleksi; Elo, Petra; Nieminen, Jyrki; Puolakka, Timo; Eskelinen, Antti

    2016-02-01

    Background and purpose - There are no international guidelines to define adverse reaction to metal debris (ARMD). Muscle fatty atrophy has been reported to be common in patients with failing metal-on-metal (MoM) hip replacements. We assessed whether gluteal muscle fatty atrophy is associated with elevated blood metal ion levels and pseudotumors. Patients and methods - 263 consecutive patients with unilateral ASR XL total hip replacement using a posterior approach and with an unoperated contralateral hip were included in the study. All patients had undergone a standard screening program at our institution, including MRI and blood metal ion measurement. Muscle fatty atrophy was graded as being absent, mild, moderate, or severe in each of the gluteal muscles. Results - The prevalance of moderate-to-severe gluteal muscle atrophy was low (12% for gluteus minimus, 10% for gluteus medius, and 2% for gluteus maximus). Muscle atrophy was neither associated with elevated blood metal ion levels (>?5 ppb) nor with the presence of a clear (solid- or mixed-type) pseudotumor seen in MRI. A combination of moderate-to-severe atrophy in MRI, elevated blood metal ion levels, and MRI-confirmed mixed or solid pseudotumor was rare. Multivariable regression revealed that "preoperative diagnosis other than osteoarthrosis" was the strongest predictor of the presence of fatty atrophy. Interpretation - Gluteal muscle atrophy may be a clinically significant finding with influence on hip muscle strength in patients with MoM hip replacement. However, our results suggest that gluteal muscle atrophy seen in MRI is not associated with either the presence or severity of ARMD, at least not in patients who have been operated on using the posterior approach. PMID:26427902

  6. Auditory and Visual Health after Ten Years of Exposure to Metal-on-Metal Hip Prostheses: A Cross-Sectional Study Follow Up

    PubMed Central

    Prentice, Jennifer R.; Blackwell, Christopher S.; Raoof, Naz; Bacon, Paul; Ray, Jaydip; Hickman, Simon J.; Wilkinson, J. Mark

    2014-01-01

    Case reports of patients with mal-functioning metal-on-metal hip replacement (MoMHR) prostheses suggest an association of elevated circulating metal levels with visual and auditory dysfunction. However, it is unknown if this is a cumulative exposure effect and the impact of prolonged low level exposure, relevant to the majority of patients with a well-functioning prosthesis, has not been studied. Twenty four male patients with a well-functioning MoMHR and an age and time since surgery matched group of 24 male patients with conventional total hip arthroplasty (THA) underwent clinical and electrophysiological assessment of their visual and auditory health at a mean of ten years after surgery. Median circulating cobalt and chromium concentrations were higher in patients after MoMHR versus those with THA (P<0.0001), but were within the Medicines and Healthcare Products Regulatory Agency (UK) investigation threshold. Subjective auditory tests including pure tone audiometric and speech discrimination findings were similar between groups (P>0.05). Objective assessments, including amplitude and signal-to-noise ratio of transient evoked and distortion product oto-acoustic emissions (TEOAE and DPOAE, respectively), were similar for all the frequencies tested (P>0.05). Auditory brainstem responses (ABR) and cortical evoked response audiometry (ACR) were also similar between groups (P>0.05). Ophthalmological evaluations, including self-reported visual function by visual functioning questionnaire, as well as binocular low contrast visual acuity and colour vision were similar between groups (P>0.05). Retinal nerve fibre layer thickness and macular volume measured by optical coherence tomography were also similar between groups (P>0.05). In the presence of moderately elevated metal levels associated with well-functioning implants, MoMHR exposure does not associate with clinically demonstrable visual or auditory dysfunction. PMID:24621561

  7. Current expert views on metal-on-metal hip resurfacing arthroplasty. Consensus of the 6th advanced Hip resurfacing course, Ghent, Belgium, May 2014.

    PubMed

    Van Der Straeten, Catherine; De Smet, Koen A

    2016-02-01

    This paper reports the consensus of an international faculty of expert metal-on-metal (MoM) hip resurfacing surgeons, with a combined experience of over 40,000 cases, on the current status of hip resurfacing arthroplasty. Indications, design and metallurgy issues, release of metal ions and adverse soft tissue reactions to particles, management of problematic cases and revisions, as well as required experience and training are covered. The overall consensus is that MoM hip resurfacing should not be banned and should be viewed separately from MoM total hip arthroplasty (THA) with a large diameter head because of the different design and wear behaviour related to the taper/trunnion connection. The use of hip resurfacing has decreased worldwide but specialist centres continue to advocate hip resurfacing in young and active male patients. Regarding age the general recommendation is to avoid hip resurfacing in men older than 65 and in women older than 55, depending on the patient activity and bone quality. Female gender is considered a relative contraindication. Most surgeons would not implant a MoM hip in women who would still like a child. Regardless of gender, there is a consensus not to perform hip resurfacing in case of a femoral head size smaller than 46 mm and in patients with renal insufficiency or with a known metal allergy. Regarding follow-up of hip resurfacing and detection of adverse local tissue reactions, metal ion measurements, MRI and ultrasound are advocated depending on the local expertise. The consensus is that hip resurfacing should be limited to high volume hip surgeons, who are experienced in hip resurfacing or trained to perform hip resurfacing in a specialist centre. PMID:26449333

  8. The chemical form of metallic debris in tissues surrounding metal-on-metal hips with unexplained failure.

    PubMed

    Hart, Alister J; Quinn, Paul D; Sampson, Barry; Sandison, Ann; Atkinson, Kirk D; Skinner, John A; Powell, Jonathan J; Mosselmans, J Fred W

    2010-11-01

    Implant-derived material from metal-on-metal (MOM) hip arthroplasties may be responsible for an unexplained tissue inflammatory response. The chemical form of the metal species in the tissues is predominantly chromium (Cr), but the currently used techniques have not been able to determine whether this is Cr(III) phosphate or Cr(III) oxide. The analytical challenge must overcome the fact that the metal in the tissues is at a relatively low concentration and tissue preparation or the microscopy beam used can affect the results. Microfocus X-ray spectroscopy using a synchrotron beam is useful in addressing both these issues. Using this technique we compared tissue from failed MOM hips with: (1) tissue from metal-on-polyethylene (MOP) hips; (2) chemical standards; (3) metal discs cut from MOM hips. The most abundant implant-related species in all MOM hip tissues contained Cr. Comparison with standards revealed the chemical form was Cr(III) phosphate, which did not vary with manufacturer type (four types analysed) or level of blood metal ions. Cobalt (Co) and molybdenum (Mo) were occasionally present in areas of high Cr. Co was normally found in a metallic state in the tissue, while Mo was found in an oxidized state. The variety of metallic species may have arisen from corrosion, wear or a combination of both. No evidence of Cr(VI) was seen in the tissues examined. PMID:20541630

  9. Contact mechanics studies of an ellipsoidal contact bearing surface of metal-on-metal hip prostheses under micro-lateralization.

    PubMed

    Wang, Ling; Liu, Xiaohua; Li, Dichen; Liu, Feng; Jin, Zhongmin

    2014-04-01

    The morphology of the contact bearing surfaces plays an important role in the contact mechanics and potential wear of metal-on-metal (MOM) hip prostheses. An ellipsoidal bearing surface was proposed for MOM hip implants and the corresponding contact mechanics were studied by using the finite element method (FEM) under both standard and micro-lateralization conditions. When under micro-lateralization, the maximum contact pressure decreased from 927.3MPa to 203.0MPa, with increased ellipticity ratio medial-laterally. And the contact region was found to shift from the rim of the cup to the inner region compared to the spherical design. Under standard conditions, an increasing trend of the maximum contact pressure for the acetabular component was predicted as the major radius of the ellipsoidal bearing surface was increased. Nevertheless, the maximum contact pressure reached an asymptotic value when the ellipticity ratio was increased to 1.04. Therefore it is critical to optimize the ellipticity ratio in order to reduce the contact pressure under micro-lateralization condition and yet not to cause a markedly increased contact pressure under normal condition. Additionally, the maximum contact pressure in the ellipsoidal bearing surface remained relatively constant with the increased micro-lateralization. It is concluded that an ellipsoidal bearing surface morphology may be a promising alternative by offering better contact mechanisms when micro-lateralization should occur and attributing to minimized wear. PMID:24461516

  10. Good sensitivity and specificity of ultrasound for detecting pseudotumors in 83 failed metal-on-metal hip replacements

    PubMed Central

    Lainiala, Olli; Elo, Petra; Reito, Aleksi; Pajamki, Jorma; Puolakka, Timo; Eskelinen, Antti

    2015-01-01

    Background and purpose Ultrasound is used for imaging of pseudotumors associated with metal-on-metal (MoM) hips. Ultrasound has been compared with magnetic resonance imaging, but to date there have been no studies comparing ultrasound findings and revision findings. Methods We evaluated the sensitivity and specificity of preoperative ultrasound for detecting pseudotumors in 82 patients with MoM hip replacement (82 hips). Ultrasound examinations were performed by 1 of 3 musculoskeletal radiologists, and pseudotumors seen by ultrasound were retrospectively classified as fluid-filled, mixed-type, or solid. Findings at revision surgery were retrieved from surgical notes and graded according to the same system as used for ultrasound findings. Results Ultrasound had a sensitivity of 83% (95% CI: 6393) and a specificity of 92% (CI: 8296) for detecting trochanteric region pseudotumors, and a sensitivity of 79% (CI: 6289) and a specificity of 94% (CI: 8398) for detecting iliopsoas-region pseudotumors. Type misclassification of pseudotumors found at revision occurred in 8 of 23 hips in the trochanteric region and in 19 of 33 hips in the iliopsoas region. Interpretation Despite the discrepancy in type classification between ultrasound and revision findings, the presence of pseudotumors was predicted well with ultrasound in our cohort of failed MoM hip replacements. PMID:25582840

  11. Chromium and cobalt ion concentrations in blood and serum following various types of metal-on-metal hip arthroplasties

    PubMed Central

    2013-01-01

    Background and purpose Widely different metal ion concentrations in blood and serum have been reported with metal-on-metal (MoM) implants. We reviewed the literature on blood and serum ion concentrations of chromium (Cr) and cobalt (Co) following various MoM hip arthroplasties. Methods Studies were searched for in the Medline database, Embase, and the Cochrane Database of Systematic Reviews. Highest mean or median ion concentrations of Cr and Co after a minimum of 1 year of follow-up were extracted and grouped according to sample- and articulation type, and average values were calculated. Results 43 studies were included and 16 different MoM implants were identified. For the different types of bearings, average ion concentrations and range were calculated from the mean or median ion concentration. The average Cr concentration ranged between 0.5 and 2.5 ?g/L in blood and between 0.8 and 5.1 ?g/L in serum. For Co, the range was 0.73.4 ?g/L in blood and 0.37.5 ?g/L in serum. Interpretation When the average blood ion concentrations calculated for the different implants, together with the concentrations measured in the individual studies, were compared with the upper acceptable limit for Cr and Co in blood, no clear pattern was recognized. Furthermore, we were unable to detect any clear difference in ion concentrations between different types of implants (THA and resurfacing). PMID:23594249

  12. Clinical usefulness of blood metal measurements to assess the failure of metal-on-metal hip implants

    PubMed Central

    Sampson, Barry; Hart, Alister

    2012-01-01

    In April 2010, a Medicines and Healthcare Products Regulatory Agency safety alert concerning all metal-on-metal (MOM) hip replacements recommended measuring chromium and cobalt concentrations when managing patients with painful prostheses. The need for this review is illustrated by the recent surge in requests for these blood tests from orthopaedic surgeons following this alert. The aim is to provide guidance to laboratories in assessing these requests and advising clinicians on interpretation. First, we summarize the basic terminology regarding the types of hip replacements, with emphasis on the MOM type. Second, we describe the clinical concerns over implant-derived wear debris in the local tissues and distant sites. Analytical aspects of the measurement of the relevant metal ions and what factors affect the levels measured are discussed. The application of inductively coupled plasma mass spectrometry techniques to the measurement of these metals is considered in detail. The biological effects of metal wear products are summarized with local toxicity and systemic biological effects considered, including carcinogenicity, genotoxicity and systemic toxicity. Clinical cases are used to illustrate pertinent points. PMID:22155921

  13. Metal ion levels and revision rates in metal-on-metal hip resurfacing arthroplasty: a comparative study.

    PubMed

    Robinson, Patrick G; Wilkinson, Andrew J; Meek, Robert M D

    2014-01-01

    Metal-on-metal (MoM) bearings in hip surgery are related to increased blood levels of metal ions. The nature of the relationship between ion levels and failure is still not fully understood. This study compares three cohorts of patients, 120 patients in each cohort, treated with a hip resurfacing arthroplasty, grouped by brand and diameter of femoral component on average four years postoperatively: Birmingham Hip Resurfacing ?50 mm, Durom resurfacing ?50 mm and Durom resurfacing <50 mm. The median blood ion levels of cobalt and chromium were significantly lower in the cohort with the large Durom resurfacing than the other two cohorts (P<0.05). The large BHR and large Durom HRA had revision rates of 3.3%. The small Durom HRA had a revision rate of 8.3%. Elevated blood ion levels can indicate a failing MoM bearing. The large BHR and large Durom HRA have similar revision rates yet the large Durom HRA had significantly lower metal ion levels. When similar ion levels were reported for BHR and small Durom the latter had significantly higher revision rates. This suggests ion levels do not absolutely predict the rate of HRA failure. Since MoM generation of metal ions is not the sole reason of failure, regular clinical and radiographic follow-up should also be in place for patients with these joints. PMID:24500833

  14. In vivo evaluation of edge-loading in metal-on-metal hip resurfacing patients with pseudotumours

    PubMed Central

    Kwon, Y-M.; Mellon, S. J.; Monk, P.; Murray, D. W.; Gill, H. S.

    2012-01-01

    Objectives Pseudotumours (abnormal peri-prosthetic soft-tissue reactions) following metal-on-metal hip resurfacing arthroplasty (MoMHRA) have been associated with elevated metal ion levels, suggesting that excessive wear may occur due to edge-loading of these MoM implants. This study aimed to quantify in vivo edge-loading in MoMHRA patients with and without pseudotumours during functional activities. Methods The duration and magnitude of edge-loading in vivo was quantified during functional activities by combining the dynamic hip joint segment contact force calculated from the three-dimensional (3D) motion analysis system with the 3D reconstruction of orientation of the acetabular component and each patients specific hip joint centre, based on CT scans. Results Edge-loading in the hips with pseudotumours occurred with a four-fold increase in duration and magnitude of force compared with the hips without pseudotumours (p = 0.02). Conclusions The study provides the first in vivo evidence to support that edge-loading is an important mechanism that leads to localised excessive wear (edge-wear), with subsequent elevation of metal ion levels in MoMHRA patients with pseudotumours. PMID:23610670

  15. Genetic alterations in periprosthetic soft-tissue masses from patients with metal-on-metal hip replacement.

    PubMed

    Sarhadi, Virinder Kaur; Parkkinen, Jyrki; Reito, Aleksi; Nieminen, Jyrki; Porkka, Noora; Wirtanen, Tiina; Laitinen, Minna; Eskelinen, Antti; Knuutila, Sakari

    2015-11-01

    Adverse soft tissue reactions in patients with metal-on-metal (MoM) hip replacement are associated with cobalt (Co) and chromium (Cr) particles released from the implant. Exposing the patients to long periods of increased metal ions concentrations resulting from the wear of these implants poses an increased risk of genotoxicity/mutagenicity. A variable proportion of patients develop periprosthetic soft-tissue masses or pseudotumors at the site of the implant. There is a concern that exposure to increased metal ions could increase the risk of cancer. In order to investigate whether the periprosthetic soft-tissue mass harbours any cancer- related genetic alterations, we studied DNA isolated from periprosthetic tissues of 20 patients with MoM hip replacement, for copy number alterations and mutations in hotspot regions of 50 cancer genes using aCGH and amplicon-based next generation sequencing. Our results showed copy number gains at 12q14.3 and 21q21.1in tumour from patient diagnosed with liposarcoma. Copy number alterations in periprosthetic tissues were seen in three other patients, one had a region of gain at 9q24.1 affecting JAK2 and INSL6, and two patients had region of gain at 6p21.1, affecting RUNX2. Mutation analysis showed V1578del mutation in NOTCH1 in two patients. The copy number alterations and mutations seen in periprosthetic soft-tissue masses are earlier reported in either haematological malignancies or in osteoblast related bone dysplasia. The presence of genetic anomalies was associated with longer in-situ time of the implant. Our findings warrant the need of similar studies in larger patient cohorts to evaluate the risk of development of neoplastic alterations in periprosthetic tissues of patients with MoM hip replacement. PMID:26355908

  16. A simulator study of adverse wear with metal and cement debris contamination in metal-on-metal hip bearings

    PubMed Central

    Halim, T.; Clarke, I. C.; Burgett-Moreno, M. D.; Donaldson, T. K.; Savisaar, C.; Bowsher, J. G.

    2015-01-01

    Objectives Third-body wear is believed to be one trigger for adverse results with metal-on-metal (MOM) bearings. Impingement and subluxation may release metal particles from MOM replacements. We therefore challenged MOM bearings with relevant debris types of cobalt–chrome alloy (CoCr), titanium alloy (Ti6Al4V) and polymethylmethacrylate bone cement (PMMA). Methods Cement flakes (PMMA), CoCr and Ti6Al4V particles (size range 5 µm to 400 µm) were run in a MOM wear simulation. Debris allotments (5 mg) were inserted at ten intervals during the five million cycle (5 Mc) test. Results In a clean test phase (0 Mc to 0.8 Mc), lubricants retained their yellow colour. Addition of metal particles at 0.8 Mc turned lubricants black within the first hour of the test and remained so for the duration, while PMMA particles did not change the colour of the lubricant. Rates of wear with PMMA, CoCr and Ti6Al4V debris averaged 0.3 mm3/Mc, 4.1 mm3/Mc and 6.4 mm3/Mc, respectively. Conclusions Metal particles turned simulator lubricants black with rates of wear of MOM bearings an order of magnitude higher than with control PMMA particles. This appeared to model the findings of black, periarticular joint tissues and high CoCr wear in failed MOM replacements. The amount of wear debris produced during a 500 000-cycle interval of gait was 30 to 50 times greater than the weight of triggering particle allotment, indicating that MOM bearings were extremely sensitive to third-body wear. Cite this article: Bone Joint Res 2015;4:29–37. PMID:25736072

  17. Effect of microseparation on contact mechanics in metal-on-metal hip replacements-A finite element analysis.

    PubMed

    Liu, Feng; Williams, Sophie; Fisher, John

    2015-08-01

    Some early failures of metal-on-metal (MoM) hip replacements associated with elevated wear have caused concerns for the use of this bearing combination. Simulator studies have shown that microseparation and its associated rim contact and edge loading may produce the most severe wear in MoM bearings. It is generally recognized that this high wear can be attributed to the high contact stress of the head on the rim of the cup. In this study, an improved finite element contact model that incorporates an elastic-perfectly plastic material property for cobalt-chrome alloy of the metal bearing was developed in an attempt to provide an accurate prediction of the stress and strain for the rim contact. The effects of the microseparation displacement (0.1-2 mm), cup inclination angle (25-65) and cup rim radius (0.5-4 mm) on the contact stress/strain were investigated. The results show that a translational displacement >0.1 mm under a load >0.5 kN can produce a highly concentrated contact stress at the surface of the cup rim which can lead to plastic deformation. This study also suggests that the magnitude of translational displacement was the major factor that determined the severity of the contact conditions and level of stress and strain under microseparation conditions. Future studies will address the effect of surgical translational and rotational malposition and component design on the magnitude of microseparation, contact stress and strain and severity of wear. PMID:25370809

  18. Activation of noble metals on metal-carbide surfaces: novel catalysts for CO oxidation, desulfurization and hydrogenation reactions.

    PubMed

    Rodriguez, Jos A; Illas, Francesc

    2012-01-14

    This perspective article focuses on the physical and chemical properties of highly active catalysts for CO oxidation, desulfurization and hydrogenation reactions generated by depositing noble metals on metal-carbide surfaces. To rationalize structure-reactivity relationships for these novel catalysts, well-defined systems are required. High-resolution photoemission, scanning tunneling microscopy (STM) and first-principles periodic density-functional (DF) calculations have been used to study the interaction of metals of Groups 9, 10 and 11 with MC(001) (M = Ti, Zr, V, Mo) surfaces. DF calculations give adsorption energies that range from 2 eV (Cu, Ag, Au) to 6 eV (Co, Rh, Ir). STM images show that Au, Cu, Ni and Pt grow on the carbide substrates forming two-dimensional islands at very low coverage, and three-dimensional islands at medium and large coverages. In many systems, the results of DF calculations point to the preferential formation of admetal-C bonds with significant electronic perturbations in the admetal. TiC(001) and ZrC(001) transfer some electron density to the admetals facilitating bonding of the adatom with electron-acceptor molecules (CO, O(2), C(2)H(4), SO(2), thiophene, etc.). For example, the Cu/TiC(001) and Au/TiC(001) systems are able to cleave both S-O bonds of SO(2) at a temperature as low as 150 K, displaying a reactivity much larger than that of TiC(001) or extended surfaces of bulk copper and gold. At temperatures below 200 K, Au/TiC is able to dissociate O(2) and perform the 2CO + O(2)? 2CO(2) reaction. Furthermore, in spite of the very poor hydrodesulfurization performance of TiC(001) or Au(111), a Au/TiC(001) surface displays an activity for the hydrodesulfurization of thiophene higher than that of conventional Ni/MoS(x) catalysts. In general, the Au/TiC system is more chemically active than systems generated by depositing Au nanoparticles on oxide surfaces. Thus, metal carbides are excellent supports for enhancing the chemical reactivity of noble metals. PMID:22108864

  19. Activation of Noble Metals on Metal-Carbide Surfaces: Novel Catalysts for CO Oxidation, Desulfurization and Hydrogenation Reactions

    SciTech Connect

    Rodriguez J. A.; Illas, F.

    2012-01-01

    This perspective article focuses on the physical and chemical properties of highly active catalysts for CO oxidation, desulfurization and hydrogenation reactions generated by depositing noble metals on metal-carbide surfaces. To rationalize structure-reactivity relationships for these novel catalysts, well-defined systems are required. High-resolution photoemission, scanning tunneling microscopy (STM) and first-principles periodic density-functional (DF) calculations have been used to study the interaction of metals of Groups 9, 10 and 11 with MC(001) (M = Ti, Zr, V, Mo) surfaces. DF calculations give adsorption energies that range from 2 eV (Cu, Ag, Au) to 6 eV (Co, Rh, Ir). STM images show that Au, Cu, Ni and Pt grow on the carbide substrates forming two-dimensional islands at very low coverage, and three-dimensional islands at medium and large coverages. In many systems, the results of DF calculations point to the preferential formation of admetal-C bonds with significant electronic perturbations in the admetal. TiC(001) and ZrC(001) transfer some electron density to the admetals facilitating bonding of the adatom with electron-acceptor molecules (CO, O{sub 2}, C{sub 2}H{sub 4}, SO{sub 2}, thiophene, etc.). For example, the Cu/TiC(001) and Au/TiC(001) systems are able to cleave both S-O bonds of SO{sub 2} at a temperature as low as 150 K, displaying a reactivity much larger than that of TiC(001) or extended surfaces of bulk copper and gold. At temperatures below 200 K, Au/TiC is able to dissociate O{sub 2} and perform the 2CO + O{sub 2} {yields} 2CO{sub 2} reaction. Furthermore, in spite of the very poor hydrodesulfurization performance of TiC(001) or Au(111), a Au/TiC(001) surface displays an activity for the hydrodesulfurization of thiophene higher than that of conventional Ni/MoS{sub x} catalysts. In general, the Au/TiC system is more chemically active than systems generated by depositing Au nanoparticles on oxide surfaces. Thus, metal carbides are excellent supports for enhancing the chemical reactivity of noble metals.

  20. Which imaging modality is most effective for identifying pseudotumours in metal-on-metal hip resurfacings requiring revision

    PubMed Central

    Matharu, G. S.; Mansour, R.; Dada, O.; Ostlere, S.; Pandit, H. G.; Murray, D. W.

    2016-01-01

    Aims The aims of this study were to compare the diagnostic test characteristics of ultrasound alone, metal artefact reduction sequence MRI (MARS-MRI) alone, and ultrasound combined with MARS-MRI for identifying intra-operative pseudotumours in metal-on-metal hip resurfacing (MoMHR) patients undergoing revision surgery. Methods This retrospective diagnostic accuracy study involved 39 patients (40 MoMHRs). The time between imaging modalities was a mean of 14.6 days (0 to 90), with imaging performed at a mean of 5.3 months (0.06 to 12) before revision. The prevalence of intra-operative pseudotumours was 82.5% (n = 33). Results Agreement with the intra-operative findings was 82.5% (n = 33) for ultrasound alone, 87.5% (n = 35) for MARS-MRI alone, and 92.5% (n = 37) for ultrasound and MARS-MRI combined. The diagnostic characteristics for ultrasound alone and MARS-MRI alone reached similar sensitivities (90.9% vs 93.9%) and positive predictive values (PPVs; 88.2% vs 91.2%), but higher specificities (57.1% vs 42.9%) and negative predictive values (NPVs; 66.7% vs 50.0%) were achieved with MARS-MRI. Ultrasound and MARS-MRI combined produced 100% sensitivity and 100% NPV, whilst maintaining both specificity (57.1%) and PPV (91.7%). For the identification of a pseudotumour, which was confirmed at revision surgery, agreement was substantial for ultrasound and MARS-MRI combined (κ = 0.69), moderate for MARS-MRI alone (κ = 0.54), and fair for ultrasound alone (κ = 0.36). Discussion These findings suggest that ultrasound and/or MARS-MRI have a role when assessing patients with a MoMHR, with the choice dependent on local financial constraints and the availability of ultrasound expertise. However in patients with a MoMHR who require revision, combined imaging was most effective. Take home message: Combined imaging with ultrasound and MARS-MRI always identified intra-operative pseudotumours if present. Furthermore, if neither imaging modality showed a pseudotumour, one was not found intra-operatively. Cite this article: Bone Joint J 2016;98-B:40–8. PMID:26733514

  1. Effects of cobalt and chromium ions at clinically equivalent concentrations after metal-on-metal hip replacement on human osteoblasts and osteoclasts: implications for skeletal health.

    PubMed

    Andrews, Rebecca E; Shah, Karan M; Wilkinson, J Mark; Gartland, Alison

    2011-10-01

    Metal-on-metal hip replacement (MOMHR) using large diameter bearings has become a popular alternative to conventional total hip arthroplasty, but is associated with elevated local tissue and circulating levels of chromium (Cr) and cobalt (Co) ions that may affect bone health. We examined the effects of acute and chronic exposure to these metals on human osteoblast and osteoclast formation and function over a clinically relevant concentration range previously reported in serum and within hip synovial fluid in patients after MOMHR. SaOS-2 cells were cultured with Co(2+), Cr(3+) and Cr(6+) for 3 days after which an MTS assay was used to assess cell viability, for 13 days after which alkaline phosphatase and cell viability were assessed and for 21 days after which nodule formation was assessed. Monocytes were isolated from human peripheral blood and settled onto dentine disks then cultured with M-CSF and RANKL plus either Co(2+), Cr(3+) or Cr(6+) ions for 21 days from day 0 or between days 14 and 21. Cells were fixed and stained for TRAP and osteoclast number and amount of resorption per dentine disk determined. Co(2+) and Cr(3+) did not affect osteoblast survival or function over the clinically equivalent concentration range, whilst Cr(6+) reduced osteoblast survival and function at concentrations within the clinically equivalent serum range after MOMHR (IC(50) =2.2 ?M). In contrast, osteoclasts were more sensitive to metal ions exposure. At serum levels a mild stimulatory effect on resorption in forming osteoclasts was found for Co(2+) and Cr(3+), whilst at higher serum and synovial equivalent concentrations, and with Cr(6+), a reduction in cell number and resorption was observed. Co(2+) and Cr(6+) within the clinical range reduced cell number and resorption in mature osteoclasts. Our data suggest that metal ions at equivalent concentrations to those found in MOMHR affect bone cell health and may contribute to the observed bone-related complications of these prostheses. PMID:21689801

  2. The immunobiology of cobalt: demonstration of a potential aetiology for inflammatory pseudotumours after metal-on-metal replacement of the hip.

    PubMed

    Lawrence, H; Deehan, D; Holland, J; Kirby, J; Tyson-Capper, A

    2014-09-01

    Abnormal wear of cobalt-containing metal-on-metal joints is associated with inflammatory pseudotumours. Cobalt ions activate human toll-like receptor 4 (TLR4), which normally responds to bacterial lipopolysaccharide (LPS) in sepsis. Activation of TLR4 by LPS increases the expression of chemokines IL-8 and CXCL10, which recruit leukocytes and activated T-cells, respectively. This study was designed to determine whether cobalt induces a similar inflammatory response to LPS by promoting the expression of IL-8 and CXCL10. A human monocytic cell line, derived from acute monocytic leukaemia, was treated with cobalt ions and expression of IL-8 and CXCL10 measured at mRNA and protein levels. Cobalt-treated macrophages showed a 60-fold increase in IL-8 mRNA, and an eightfold increase in production of the mature chemokine (both p < 0.001); expression of the CXCL10 gene and protein was also significantly increased by cobalt (both p < 0.001). Experiments were also performed in the presence of CLI-095, a TLR4-specific antagonist which abrogated the cobalt-mediated increase in IL-8 and CXCL10 expression. These findings suggest that cobalt ions induce inflammation similar to that observed during sepsis by the simultaneous activation of two TLR4-mediated signalling pathways. These pathways result in increased production of IL-8 and CXCL10, and may be implicated in pseudotumour formation following metal-on-metal replacement. PMID:25183586

  3. A Two Centre Study to Assess the Long-term Performance of the Pinnacle™ Cup With a Metal-on-Metal Bearing in Primary Total Hip Replacement

    ClinicalTrials.gov

    2014-04-29

    Rheumatoid Arthritis; Osteoarthritis; Post-traumatic Arthritis; Collagen Disorders; Avascular Necrosis; Traumatic Femoral Fractures; Nonunion of Femoral Fractures; Congenital Hip Dysplasia; Slipped Capital Femoral Epiphysis

  4. Accuracy of methods for calculating volumetric wear from coordinate measuring machine data of retrieved metal-on-metal hip joint implants.

    PubMed

    Lu, Zhen; McKellop, Harry A

    2014-03-01

    This study compared the accuracy and sensitivity of several numerical methods employing spherical or plane triangles for calculating the volumetric wear of retrieved metal-on-metal hip joint implants from coordinate measuring machine measurements. Five methods, one using spherical triangles and four using plane triangles to represent the bearing and the best-fit surfaces, were assessed and compared on a perfect hemisphere model and a hemi-ellipsoid model (i.e. unworn models), computer-generated wear models and wear-tested femoral balls, with point spacings of 0.5, 1, 2 and 3?mm. The results showed that the algorithm (Method 1) employing spherical triangles to represent the bearing surface and to scale the mesh to the best-fit surfaces produced adequate accuracy for the wear volume with point spacings of 0.5, 1, 2 and 3?mm. The algorithms (Methods 2-4) using plane triangles to represent the bearing surface and to scale the mesh to the best-fit surface also produced accuracies that were comparable to that with spherical triangles. In contrast, if the bearing surface was represented with a mesh of plane triangles and the best-fit surface was taken as a smooth surface without discretization (Method 5), the algorithm produced much lower accuracy with a point spacing of 0.5?mm than Methods 1-4 with a point spacing of 3?mm. PMID:24531891

  5. Chromium and cobalt ion release following the Durom high carbon content, forged metal-on-metal surface replacement of the hip.

    PubMed

    Vendittoli, P-A; Mottard, S; Roy, A G; Dupont, C; Lavigne, M

    2007-04-01

    We evaluated the concentrations of chromium and cobalt ions in blood after metal-on-metal surface replacement arthroplasty using a wrought-forged, high carbon content chromium-cobalt alloy implant in 64 patients. At one year, mean whole blood ion levels were 1.61 microg/L (0.4 to 5.5) for chromium and 0.67 microg/L (0.23 to 2.09) for cobalt. The pre-operative ion levels, component size, female gender and the inclination of the acetabular component were inversely proportional to the values of chromium and/or cobalt ions at one year postoperatively. Other factors, such as age and level of activity, did not correlate with the levels of metal ions. We found that the levels of the ions in the serum were 1.39 and 1.37 times higher for chromium and cobalt respectively than those in the whole blood. The levels of metal ions obtained may be specific to the hip resurfacing implant and reflect its manufacturing process. PMID:17463109

  6. Influence of head size on the development of metallic wear and on the characteristics of carbon layers in metal-on-metal hip joints

    PubMed Central

    Sprecher, Christoph M; Wimmer, Markus A; Milz, Stefan; Taeger, Georg

    2009-01-01

    Background and purpose Particles originating from the articulating surfaces of hip endoprostheses often induce an inflammatory response, which can be related to implant failure. We therefore analyzed the metal content in capsular tissue from 44 McKee-Farrar metal-on-metal hip prostheses (with 3 different head sizes) and we also analyzed the morphological structure of layers located on articulating surfaces. Methods Atomic absorption spectrometry (AAS) was used to analyze the metal content in capsular tissue. Visually detectable carbon layers located on the articulating surfaces were evaluated using scanning electron microscopy (SEM), energy-dispersive Xray spectroscopy (EDX), and X-ray photoelectron spectroscopy (XPS). Results Metallic debris was detected in all capsular tissue samples but no statistically significant differences in metal content were found in relation to implant head size. The morphological characteristics of the different layer zones allowed an exact analysis of contact and non-contact areas. Furthermore, surface layers appear to have a protective function because they can prevent sharp-edged particles from damaging the prostheses surface. Interpretation The implant head size does not appear to influence the amount of metallic debris. The layers obviously act like a lubricating agent because the protection function does not occur in regions without layers where the metal surface often shows numerous scratches. As layers are not generated immediately after the implantation of hip prostheses, these findings may at least partially explain the high amount of wear early after implantation. PMID:19421914

  7. Cup inclination angle of greater than 50 degrees increases whole blood concentrations of cobalt and chromium ions after metal-on-metal hip resurfacing.

    PubMed

    Hart, A J; Buddhdev, P; Winship, P; Faria, N; Powell, J J; Skinner, J A

    2008-01-01

    A cup inclination angle greater than 45 degrees is associated with increased wear rates of metal on polyethylene (MOP) hip replacements. The same maybe true for metal on metal (MOM) hips yet this has not been clearly shown. We measured the acetabular inclination angle from plain radiographs, and whole blood metal ion levels using Inductively Coupled Plasma Mass Spectrometry of 26 patients (mean Harris Hip Score 94 and mean time post op of 22 months) with Birmingham Hip Resurfacings. We identified a threshold level of 50 degrees cup inclination. Below this threshold, the mean whole blood cobalt and chromium were 1.6 ppb and 1.88 ppb respectively; above this threshold, the mean blood cobalt and chromium were 4.45 ppb and 4.3 ppb respectively. These differences were significant cobalt (p<0.01) and chromium (p=0.01). All patients above the threshold had metal levels greater than any of the patients below the threshold. For 14 patients, who returned one year later for a repeat blood metal level measurement, cobalt and chromium levels were very similar. The effect of an acetabular inclination angle of greater than 50 degrees on wear rates of MOM hips, as measured through blood metal ion levels, appears to be similar to that seen with MOP hips. Additionally, our new analytical methods may allow blood metal levels to be used as a realistic biomarker of in vivo wear rate of MOM hips. The implication is that metal levels can be minimised with optimal orientation of the acetabular component. PMID:18924077

  8. Asymptomatic prospective and retrospective cohorts with metal-on-metal hip arthroplasty indicate acquired lymphocyte reactivity varies with metal ion levels on a group basis

    PubMed Central

    Hallab, NJ; Caicedo, M; McAllister, K; Skipor, A; Amstutz, H; Jacobs, JJ

    2012-01-01

    Some tissues from metal-on-metal (MoM) hip arthroplasty revisions have shown evidence of adaptive-immune reactivity (i.e., excessive peri-implant lymphocyte infiltration/activation). We hypothesized that, prior to symptoms, some people with MoM hip arthroplasty will develop quantifiable metal-induced lymphocyte reactivity responses related to peripheral metal ion levels. We tested 3 cohorts (Group-1: n=21 prospective longitudinal MoM hip arthroplasty; Group-2: n=17 retrospective MoM hip arthroplasty; and Group-3: n=20 controls without implants). We compared implant position, metal-ion release, and immuno-reactivity. MoM cohorts had elevated (p<0.01) amounts of serum Co and Cr compared to controls as early as 3 mos post-op (Group-1:1.2ppb-Co, 1.5ppb-Cr; Group-2: 3.4ppb-Co,, 5.4ppb-Cr; Group-3: 0.01ppb-Co, 0.1ppb-Cr). However, only after 1 to 4 yrs post-op did 56% of Group-1 develop metal-reactivity (vs. 5%pre-op, metal-LTT, SI>2), compared with 76% of Group-2 and 15% of Group-3 controls (patch testing was a poor diagnostic indicator with only 1/21 Group-1 positive). Higher cup-abduction angles (50 vs. 40) in Group-1 were associated with higher serum Cr (p<0.07). However, sub-optimal cup-anteversion angles (9 vs. 20) had higher serum Co (p<0.08). Serum Cr and Co were significantly elevated in reactive vs. non-reactive Group-1 participants (p<0.04). CD4+CD69+ T-helper lymphocytes (but not CD8+) and IL-1?, IL-12 and IL-6 cytokines were all significantly elevated in metal-reactive vs. non-reactive Group-1 participants. Our results showed that lymphocyte reactivity to metals can develop within the first 1 to 4 years after MoM arthroplasty in asymptomatic patients and lags increases in metal ion levels. This increased metal reactivity was more prevalent in those individuals with extreme cup angles and higher amounts of circulating metal. PMID:22941579

  9. Prevalence of Failure due to Adverse Reaction to Metal Debris in Modern, Medium and Large Diameter Metal-on-Metal Hip Replacements – The Effect of Novel Screening Methods: Systematic Review and Metaregression Analysis

    PubMed Central

    Reito, Aleksi; Lainiala, Olli; Elo, Petra; Eskelinen, Antti

    2016-01-01

    Metal-on-metal (MoM) hip replacements were used for almost a decade before adverse reactions to metal debris (ARMD) were found to be a true clinical problem. Currently, there is a paucity of evidence regarding the usefulness of systematic screening for ARMD. We implemented a systematic review and meta-analysis to establish the prevalence of revision confirmed ARMD stratified by the use of different screening protocols in patients with MoM hip replacements. Five levels of screening were identified: no screening (level 0), targeted blood metal ion measurement and/or cross-sectional imaging (level 1), metal ion measurement without imaging (level 2), metal ion measurement with targeted imaging (level 3) and comprehensive screening (both metal ions and imaging for all; level 4). 122 studies meeting our eligibility criteria were included in analysis. These studies included 144 study arms: 100 study arms with hip resurfacings, 33 study arms with large-diameter MoM total hip replacements (THR), and 11 study arms with medium-diameter MoM THRs. For hip resurfacing, the lowest prevalence of ARMD was seen with level 0 screening (pooled prevalence 0.13%) and the highest with level 4 screening (pooled prevalace 9.49%). Pooled prevalence of ARMD with level 0 screening was 0.29% and with level 4 screening 21.3% in the large-diameter MoM THR group. In metaregression analysis of hip resurfacings, level 4 screening was superior with regard to prevalence of ARMD when compared with other levels. In the large diameter THR group level 4 screening was superior to screening 0,2 and 3. These outcomes were irrespective of follow-up time or study publication year. With hip resurfacings, routine cross-sectional imaging regardless of clinical findings is advisable. It is clear, however, that targeted metal ion measurement and/or imaging is not sufficient in the screening for ARMD in any implant concepts. However, economic aspects should be weighed when choosing the preferred screening level. PMID:26930057

  10. Peri-acetabular bone mineral density in total hip replacement

    PubMed Central

    Gauthier, L.; Dinh, L.; Beaul, P. E.

    2013-01-01

    Objectives To quantify and compare peri-acetabular bone mineral density (BMD) between a monoblock acetabular component using a metal-on-metal (MoM) bearing and a modular titanium shell with a polyethylene (PE) insert. The secondary outcome was to measure patient-reported clinical function. Methods A total of 50 patients (25 per group) were randomised to MoM or metal-on-polyethlene (MoP). There were 27 women (11 MoM) and 23 men (14 MoM) with a mean age of 61.6years (47.7 to 73.2). Measurements of peri-prosthetic acetabular and contralateral hip (covariate) BMD were performed at baseline and at one and two years follow-up. The Western Ontario and McMaster Universities osteoarthritis index (WOMAC), University of California, Los Angeles (UCLA) activity score, Harris hip score, and RAND-36 were also completed at these intervals. Results At two years, only zone 1 showed a loss in BMD (-2.5%) in MoM group compared with a gain in the MoP group (+2.2%). Zone 2 showed loss in both groups (-2.2% for MoM; -3.9% for MoP) and zones 3 and 4 a gain in both groups (+0.1% for MoM; +3.3% for MoP). No other between-group differences were detected. When adjusting for BMD of the contralateral hip, no differences in BMD were observed. The only significant differences in functional scores at two years were higher UCLA activity (7.3 (sd 1.2) vs 6.1 (sd 1.5); p = 0.01) and RAND-36 physical function (82.1 (sd 13.0) vs 64.5 (sd 26.4); p = 0.02) for MoM bearings versus MoP. One revision was performed in the MoM group, for aseptic acetabular loosening at 11months. Conclusions When controlling for systemic BMD, there were no significant differences between MoM and MoP groups in peri-acetabular BMD. However, increasing reports of adverse tissue reactions with large head MoM THR have restricted the use of the monoblock acetabular component to resurfacing only. PMID:23913361

  11. Toxicology of wear particles of cobalt-chromium alloy metal-on-metal hip implants Part II: Importance of physicochemical properties and dose in animal and in vitro studies as a basis for risk assessment.

    PubMed

    Madl, Amy K; Kovochich, Michael; Liong, Monty; Finley, Brent L; Paustenbach, Dennis J; Oberdrster, Gnter

    2015-07-01

    The objective of the Part II analysis was to evaluate animal and in vitro toxicology studies of CoCr particles with respect to their physicochemistry and dose relevance to metal-on-metal (MoM) implant patients as derived from Part I. In the various toxicology studies, physicochemical characteristics were infrequently considered and administered doses were orders of magnitude higher than what occurs in patients. Co was consistently shown to rapidly release from CoCr particles for distribution and elimination from the body. CoCr micron sized particles appear more biopersistent in vivo resulting in inflammatory responses that are not seen with similar mass concentrations of nanoparticles. We conclude, that in an attempt to obtain data for a complete risk assessment, future studies need to focus on physicochemical characteristics of nano and micron sized particles and on doses and dose metrics relevant to those generated in patients or in properly conducted hip simulator studies. PMID:25735266

  12. Profiling the third-body wear damage produced in CoCr surfaces by bone cement, CoCr, and Ti6Al4V debris: a 10-cycle metal-on-metal simulator test.

    PubMed

    Halim, Thomas; Burgett, Michelle; Donaldson, Thomas K; Savisaar, Christina; Bowsher, John; Clarke, Ian C

    2014-07-01

    Particles of bone cement (polymethyl methacrylate), CoCr and Ti6Al4V were compared for their abrasion potential against CoCr substrates. This appears to be the first study utilizing CoCr and Ti6Al4V particulates to abrade CoCr bearings and the first study profiling the morphology of third-body abrasive wear scratches in a hip simulator. The 5 mg debris allotments (median size range 140-300 m) were added to cups mounted both inverted and anatomically with metal-on-metal (MOM) bearings in a 10-cycle, hip simulator test. Surface abrasion was characterized by roughness indices and scratch profiles. Compared to third-body abrasion with metal debris, polymethyl methacrylate debris had minimal effect on the CoCr surfaces. In all, 10 cycles of abrasion with metal debris demonstrated that roughness indices (Ra, PV) increased approximately 20-fold from the unworn condition. The scratch profiles ranged 20-108 m wide and 0.5-2.8 m deep. The scratch aspect ratio (W/PV) averaged 0.03, and this very low ratio indicated that the 140 m CoCr beads had plastically deformed to create wide but shallow scratches. There was no evidence of transfer of CoCr beads to CoCr bearings. The Ti64 particles produced similar scratch morphology with the same aspect ratio as the CoCr particulates. However, the titanium particulates also showed a unique ability to flatten and adhere to the CoCr, forming smears and islands of contaminating metal on the CoCr bearings. The morphology of scratches and metal transfer produced by these large metal particulates in the simulator appeared identical to those reported on retrieved metal-on-metal bearings. PMID:25062741

  13. Uneven damage on head and liner contact surfaces of a retrieved Co-Cr-based metal-on-metal hip joint bearing: An important reason for the high failure rate.

    PubMed

    Koizumi, Yuichiro; Chen, Yan; Li, Yunping; Yamanaka, Kenta; Chiba, Akihiko; Tanaka, Shun-Ichiro; Hagiwara, Yoshihiro

    2016-05-01

    Detailed metallurgical investigations have been performed on a used Co-Cr-based metal-on-metal (MoM) hip joint bearing containing a type of liner that is commonly used in such joints. The damage on the metal-liner sliding surface was considerably more severe than that on the metal head counterpart, in terms of wear-scar density and width and microcrack frequency. Cross-sectional transmission electron microscopy revealed that a thick (>3μm) nanocrystalline layer formed on the sliding surface of the head, whereas the liner had coarse carbides embedded in it and nanocrystals were formed in a very limited region no deeper than 1μm. Comparative investigation of an unused head and a liner of identical type showed that although the chemical compositions of the liner and head were nearly identical, their microstructures were significantly different. Specifically, the grain size in the liner was larger than that in the head on average, and the grain boundaries of the liner were decorated with coarse carbides. Moreover, X-ray diffraction analysis revealed a large tensile residual stress only in the liner. These differences are possibly responsible for the wear damage on the liner being more serious than that on the head. PMID:26952456

  14. Raised levels of metal ions in the blood in patients who have undergone uncemented metal-on-polyethylene Trident-Accolade total hip replacement.

    PubMed

    Craig, P; Bancroft, G; Burton, A; Collier, S; Shaylor, P; Sinha, A

    2014-01-01

    The issues surrounding raised levels of metal ions in the blood following large head metal-on-metal total hip replacement (THR), such as cobalt and chromium, have been well documented. Despite the national popularity of uncemented metal-on-polyethylene (MoP) THR using a large-diameter femoral head, few papers have reported the levels of metal ions in the blood following this combination. Following an isolated failure of a 44 mm Trident-Accolade uncemented THR associated with severe wear between the femoral head and the trunnion in the presence of markedly elevated levels of cobalt ions in the blood, we investigated the relationship between modular femoral head diameter and the levels of cobalt and chromium ions in the blood following this THR. A total of 69 patients received an uncemented Trident-Accolade MoP THR in 2009. Of these, 43 patients (23 men and 20 women, mean age 67.0 years) were recruited and had levels of cobalt and chromium ions in the blood measured between May and June 2012. The patients were then divided into three groups according to the diameter of the femoral head used: 12 patients in the 28 mm group (controls), 18 patients in the 36 mm group and 13 patients in the 40 mm group. A total of four patients had identical bilateral prostheses in situ at phlebotomy: one each in the 28 mm and 36 mm groups and two in the 40 mm group. There was a significant increase in the mean levels of cobalt ions in the blood in those with a 36 mm diameter femoral head compared with those with a 28 mm diameter head (p = 0.013). The levels of cobalt ions in the blood were raised in those with a 40 mm diameter head but there was no statistically significant difference between this group and the control group (p = 0.152). The levels of chromium ions in the blood were normal in all patients. The clinical significance of this finding is unclear, but we have stopped using femoral heads with a diameter of ? 36 mm, and await further larger studies to clarify whether, for instance, this issue particularly affects this combination of components. PMID:24395309

  15. False aneurysm of the profunda femoris artery after total hip arthroplasty.

    PubMed

    Nozawa, M; Irimoto, M; Maezawa, K; Hirose, T; Shitoto, K; Kurosawa, H

    2000-08-01

    A false aneurysm of the profunda femoris artery occurred after metal-on-metal total hip arthroplasty in 70-year-old woman. At 39 days after the operation, the wound suddenly opened, and a large hematoma was discharged. Eleven tornade coils were inserted into the base of the false aneurysm, and the bleeding was arrested. The prevention and management of this complication are discussed. PMID:10960008

  16. Prediction of Impact Shock Vibrations at Tennis Player's Wrist Joint: Comparison between Conventional Weight Racket and Light Weight Racket with Super Large Head Size

    NASA Astrophysics Data System (ADS)

    Kawazoe, Yoshihiko; Takeda, Yukihiro; Nakagawa, Masamichi; Casolo, Federico; Tomosue, Ryoso; Yoshinari, Keiko

    The lightweight racket with handle-light configuration and large head size is recent tendency of high-tech tennis rackets, increasing power or post-impact ball velocity with an increasing racket swing speed. This paper investigated the performance of lightweight tennis racket with super-large head size in terms of feel or comfort. It predicted the effect of the mass and mass distribution of super-large sized rackets on the impact shock vibrations of the racket handle and the player's wrist joint when a player hits a flat forehand drive. The prediction is based on the identification of the racket characteristics, the damping of the racket-arm system, equivalent mass of the player's arm system and the approximate nonlinear impact analysis in tennis. A super-light weight balanced racket (mass: 292 g, the center of gravity LG: 363 mm from the butt end) and a conventional weight and weight balanced racket (349 g, LG: 323 mm) are selected as representatives. They are the super-large sized rackets made of carbon graphite with a head size of 120 square inches and the same geometry. The result showed that the shock vibration of the super-light weight balanced racket with super-large sized head is much larger than that of the conventional weight balanced type racket. It also showed that the sweet area of the former in terms of the shock vibration shifts from the center to the topside on the racket face compared to the latter. This is because the location of the grip on the racket handle is further from the location of the node on the handle of the first mode of super-light racket than that of the conventional weight racket.

  17. Is There a Benefit to Head Size Greater Than 36 mm in Total Hip Arthroplasty?

    PubMed

    Haughom, Bryan D; Plummer, Darren R; Moric, Mario; Della Valle, Craig J

    2016-01-01

    This study compares the rate of dislocation and revision for instability between 36-mm and anatomic femoral heads (large diameter metal-on-metal THA, dual-mobility bearings, and hip resurfacing arthroplasty) in patients at high risk for dislocation. A total of 501 high-risk patients, over a 10-year period, were identified (282 36-mm THA, 24 dual-mobility bearings, 83 metal-on-metal arthroplasty, and 112 hip resurfacing arthroplasty). There were 13 dislocations in the 36-mm group compared to 1 in the anatomic group (4.6% vs 0.5%; P = .005). Four patients dislocated more than once in the 36-mm group (1.4% vs 0%; P = .04), and 2 patients in the 36-mm group required a revision for instability (0.7% vs 0%; P = .11). These results suggest that anatomic head sizes significantly lower the risk of dislocation in high-risk patients. PMID:26360768

  18. CoCr wear particles generated from CoCr alloy metal-on-metal hip replacements, and cobalt ions stimulate apoptosis and expression of general toxicology-related genes in monocyte-like U937 cells

    SciTech Connect

    Posada, Olga M.; Gilmour, Denise; Tate, Rothwelle J.; Grant, M. Helen

    2014-11-15

    Cobalt-chromium (CoCr) particles in the nanometre size range and their concomitant release of Co and Cr ions into the patients' circulation are produced by wear at the articulating surfaces of metal-on-metal (MoM) implants. This process is associated with inflammation, bone loss and implant loosening and led to the withdrawal from the market of the DePuy ASR™ MoM hip replacements in 2010. Ions released from CoCr particles derived from a resurfacing implant in vitro and their subsequent cellular up-take were measured by ICP-MS. Moreover, the ability of such metal debris and Co ions to induce both apoptosis was evaluated with both FACS and immunoblotting. qRT-PCR was used to assess the effects on the expression of lymphotoxin alpha (LTA), BCL2-associated athanogene (BAG1), nitric oxide synthase 2 inducible (NOS2), FBJ murine osteosarcoma viral oncogene homolog (FOS), growth arrest and DNA-damage-inducible alpha (GADD45A). ICP-MS showed that the wear debris released significant (p < 0.05) amounts of Co and Cr ions into the culture medium, and significant (p < 0.05) cellular uptake of both ions. There was also an increase (p < 0.05) in apoptosis after a 48 h exposure to wear debris. Analysis of qRT-PCR results found significant up-regulation (p < 0.05) particularly of NOS2 and BAG1 in Co pre-treated cells which were subsequently exposed to Co ions + debris. Metal debris was more effective as an inducer of apoptosis and gene expression when cells had been pre-treated with Co ions. This suggests that if a patient receives sequential bilateral CoCr implants, the second implant may be more likely to produce adverse effects than the first one. - Highlights: • Effects of CoCr nanoparticles and Co ions on U937 cells were investigated. • Ions released from wear debris play an important role in cellular response, • Toxicity of Co ions could be related to NO metabolic processes and apoptosis. • CoCr particles were a more effective inducer of apoptosis after cell priming. • CoCr particles were a more effective inducer of gene expression after cell priming.

  19. Effect of femoral head size on risk of revision for dislocation after total hip arthroplasty

    PubMed Central

    Kostensalo, Inari; Junnila, Mika; Virolainen, Petri; Remes, Ville; Matilainen, Markus; Vahlberg, Tero; Pulkkinen, Pekka; Eskelinen, Antti; Mkel, Keijo T

    2013-01-01

    Background and purpose Previous population-based registry studies have shown that larger femoral head size is associated with reduced risk of revision for dislocation. However, the previous data have not included large numbers of hip resurfacing arthroplasties or large metal-on-metal (> 36-mm) femoral head arthroplasties. We evaluated the association between femoral component head size and the risk of revision for dislocation after THA by using Finnish Arthroplasty Register data. Patients and methods 42,379 patients who were operated during 19962010 fulfilled our criteria. 18 different cup/stem combinations were included. The head-size groups studied (numbers of cases) were 28 mm (23,800), 32 mm (4,815), 36 mm (3,320), and > 36 mm (10,444). Other risk factors studied were sex, age group (1849 years, 5059 years, 6069 years, 7079 years, and > 80 years), and time period of operation (19962000, 20012005, 20062010). Results The adjusted risk ratio in the Cox model for a revision operation due to dislocation was 0.40 (95% CI: 0.260.62) for 32-mm head size, 0.41 (0.240.70) for 36-mm head size, and 0.09 (0.050.17) for > 36-mm head size compared to implants with a head size of 28 mm. Interpretation Larger femoral heads clearly reduce the risk of dislocation. The difference in using heads of > 36 mm as opposed to 28-mm heads for the overall revision rate at 10 years follow-up is about 2%. Thus, although attractive from a mechanical point of view, based on recent less favorable clinical outcome data on these large heads, consisting mainly of metal-on-metal prostheses, one should be cautious using these implants. PMID:23799348

  20. A Novel Bradykinin-Related Dodecapeptide (RVALPPGFTPLR) from the Skin Secretion of the Fujian Large-Headed Frog (Limnonectes fujianensis) Exhibiting Unusual Structural and Functional Features

    PubMed Central

    Shi, Daning; Luo, Yu; Du, Qiang; Wang, Lei; Zhou, Mei; Ma, Jie; Li, Renjie; Chen, Tianbao; Shaw, Chris

    2014-01-01

    Bradykinin-related peptides (BRPs) are significant components of the defensive skin secretions of many anuran amphibians, and these secretions represent the source of the most diverse spectrum of such peptides so far encountered in nature. Of the many families of bioactive peptides that have been identified from this source, the BRPs uniquely appear to represent homologues of counterparts that have specific distributions and receptor targets within discrete vertebrate taxa, ranging from fishes through mammals. Their broad spectra of actions, including pain and inflammation induction and smooth muscle effects, make these peptides ideal weapons in predator deterrence. Here, we describe a novel 12-mer BRP (RVALPPGFTPLR-RVAL-(L1, T6, L8)-bradykinin) from the skin secretion of the Fujian large-headed frog (Limnonectes fujianensis). The C-terminal 9 residues of this BRP (-LPPGFTPLR) exhibit three amino acid substitutions (L/R at Position 1, T/S at Position 6 and L/F at Position 8) when compared to canonical mammalian bradykinin (BK), but are identical to the kinin sequence present within the cloned kininogen-2 from the Chinese soft-shelled turtle (Pelodiscus sinensis) and differ from that encoded by kininogen-2 of the Tibetan ground tit (Pseudopodoces humilis) at just a single site (F/L at Position 8). These data would imply that the novel BRP is an amphibian defensive agent against predation by sympatric turtles and also that the primary structure of the avian BK, ornithokinin (RPPGFTPLR), is not invariant within this taxon. Synthetic RVAL-(L1, T6, L8)-bradykinin was found to be an antagonist of BK-induced rat tail artery smooth muscle relaxation acting via the B2-receptor. PMID:25268979

  1. A novel bradykinin-related dodecapeptide (RVALPPGFTPLR) from the skin secretion of the Fujian large-headed frog (Limnonectes fujianensis) exhibiting unusual structural and functional features.

    PubMed

    Shi, Daning; Luo, Yu; Du, Qiang; Wang, Lei; Zhou, Mei; Ma, Jie; Li, Renjie; Chen, Tianbao; Shaw, Chris

    2014-10-01

    Bradykinin-related peptides (BRPs) are significant components of the defensive skin secretions of many anuran amphibians, and these secretions represent the source of the most diverse spectrum of such peptides so far encountered in nature. Of the many families of bioactive peptides that have been identified from this source, the BRPs uniquely appear to represent homologues of counterparts that have specific distributions and receptor targets within discrete vertebrate taxa, ranging from fishes through mammals. Their broad spectra of actions, including pain and inflammation induction and smooth muscle effects, make these peptides ideal weapons in predator deterrence. Here, we describe a novel 12-mer BRP (RVALPPGFTPLR-RVAL-(L, T?, L?)-bradykinin) from the skin secretion of the Fujian large-headed frog (Limnonectes fujianensis). The C-terminal 9 residues of this BRP (-LPPGFTPLR) exhibit three amino acid substitutions (L/R at Position 1, T/S at Position 6 and L/F at Position 8) when compared to canonical mammalian bradykinin (BK), but are identical to the kinin sequence present within the cloned kininogen-2 from the Chinese soft-shelled turtle (Pelodiscus sinensis) and differ from that encoded by kininogen-2 of the Tibetan ground tit (Pseudopodoces humilis) at just a single site (F/L at Position 8). These data would imply that the novel BRP is an amphibian defensive agent against predation by sympatric turtles and also that the primary structure of the avian BK, ornithokinin (RPPGFTPLR), is not invariant within this taxon. Synthetic RVAL-(L, T?, L?)-bradykinin was found to be an antagonist of BK-induced rat tail artery smooth muscle relaxation acting via the B2-receptor. PMID:25268979

  2. Biomaterial Hypersensitivity: Is It Real? Supportive Evidence and Approach Considerations for Metal Allergic Patients following Total Knee Arthroplasty

    PubMed Central

    Mihalko, William M.; Grupp, Thomas M.; Manning, Blaine T.; Dennis, Douglas A.; Goodman, Stuart B.; Saleh, Khaled J.

    2015-01-01

    The prospect of biomaterial hypersensitivity developing in response to joint implant materials was first presented more than 30 years ago. Many studies have established probable causation between first-generation metal-on-metal hip implants and hypersensitivity reactions. In a limited patient population, implant failure may ultimately be related to metal hypersensitivity. The examination of hypersensitivity reactions in current-generation metal-on-metal knee implants is comparatively limited. The purpose of this study is to summarize all available literature regarding biomaterial hypersensitivity after total knee arthroplasty, elucidate overall trends about this topic in the current literature, and provide a foundation for clinical approach considerations when biomaterial hypersensitivity is suspected. PMID:25883940

  3. The effect of femoral head size on functional outcome in primary total hip arthroplasty: a single-blinded randomised controlled trial.

    PubMed

    Hanna, Sammy A; Sewell, Mathew D; Sri-Ram, Kesavan; Miles, Jonathan; Aston, William J S; Pollock, Robin C; Carrington, Richard W J; Briggs, Timothy W R

    2012-01-01

    We conducted a prospective single-blinded randomised controlled trial to compare the functional and quality of life outcomes in two groups of patients between 60 and 80 years of age undergoing THR; the first receiving a small head (28-32 mm) metal on polyethylene (MoP) articulation, and the second receiving a large head (44-54 mm) metal on metal (MoM) articulation. We recruited 49 patients and randomised them into one of the two groups (22 MoP and 27 MoM). The results demonstrated no statistical difference in any of the assessed functional outcomes at any follow-up point (p>0.05). There were no dislocations or revisions in either group. Although it has been suggested that large head MoM articulations in THA offer superior stability and function, our results suggest that small head MoP articulations can achieve comparable ROM, function and quality of life at short-term follow-up. PMID:23250715

  4. The current state of bearing surfaces in total hip replacement.

    PubMed

    Rajpura, A; Kendoff, D; Board, T N

    2014-02-01

    We reviewed the literature on the currently available choices of bearing surface in total hip replacement (THR). We present a detailed description of the properties of articulating surfaces review the understanding of the advantages and disadvantages of existing bearing couples. Recent technological developments in the field of polyethylene and ceramics have altered the risk of fracture and the rate of wear, although the use of metal-on-metal bearings has largely fallen out of favour, owing to concerns about reactions to metal debris. As expected, all bearing surface combinations have advantages and disadvantages. A patient-based approach is recommended, balancing the risks of different options against an individual's functional demands. PMID:24493177

  5. Serum metal ion exposure after total knee arthroplasty.

    PubMed

    Luetzner, Joerg; Krummenauer, Frank; Lengel, Attila Michael; Ziegler, Joerg; Witzleb, Wolf-Christoph

    2007-08-01

    All metal implants release metal ions because of corrosion. This has been studied and debated, especially in metal-on-metal total hip arthroplasties. Total knee arthroplasty implants have large metal surface areas and therefore substantial potential for corrosion. We determined changes in serum levels of metal ions in 41 patients after cemented unconstrained total knee arthroplasty without patellar resurfacing, 18 with unilateral total knee arthroplasty (median, 66 months after surgery) and 23 patients with bilateral total knee arthroplasties (75 and 50 months after first and second surgeries, respectively). Serum concentrations of chromium, cobalt, and molybdenum were analyzed and related to the number of total knee arthroplasties and compared with those of 130 control patients without implants. The median chromium, cobalt, and molybdenum concentrations were 0.92, 3.28, and 2.55 microg/L, respectively, in the unilateral total knee arthroplasty sample and 0.98, 4.28, and 2.40 microg/L, respectively, in the bilateral total knee arthroplasty sample. We observed no difference between the serum levels in patients with unilateral and bilateral arthroplasties, but the serum levels of chromium and cobalt of both study groups were greater than those of the control group (less than 0.25 microg/L). The patients who had total knee arthroplasty had molybdenum profiles that were similar to those of the control group (median, 2.11 microg/L). PMID:17438467

  6. Mid-term clinical results of total hip arthroplasty using a Wagner standard cup for dysplastic hip

    PubMed Central

    Maezawa, Katsuhiko; Nozawa, Masahiko; Yuasa, Takahito; Aritomi, Kentaro; Ogawa, Seiki; Maruyama, Yuichiro; Kaneko, Kazuo

    2014-01-01

    Background The outcome of cementless total hip arthroplasty depends on many factors. We must not forget fundamental things those are design of outer surface of the component, that leads bone ingrowth into the prosthesis, better initial stability, and better insertional techniques. The purpose of this study was to review our experience with metal-on-metal total hip arthroplasty with a Wagner standard cup for patients who had acetabular dysplasia. Patients and methods Fifty-four patients with 55 hips underwent primary metal-on-metal total hip arthroplasty (Metasul prosthesis) with a Wagner standard cup (4448mm in outer diameter) and were followed for a minimum of 10 years. All patients received the same type of cementless femoral component (Natural hip stem) and femoral head (28mm in diameter). Results Seventeen of the 55 Wagner standard cups (30.9%) showed aseptic loosening over a mean period of 3.6 years after surgery, and there were no bone anchors on the outer surface of the 16 retrieved cups. Conclusion From our experience, the small Wagner standard cup does not achieve sufficient osteointegration and we do not recommend the use of this cup, especially for patients with acetabular dysplasia and/or those with a small stature. PMID:25561751

  7. Total protein

    MedlinePLUS

    The total protein test measures the total amount of two classes of proteins found in the fluid portion of your blood. These are albumin and globulin. Proteins are important parts of all cells and tissues. ...

  8. Total Knee Arthroplasty Failure Induced by Metal Hypersensitivity

    PubMed Central

    Gupta, Ryan; Phan, Duy; Schwarzkopf, Ran

    2015-01-01

    Patient: Female, 70 Final Diagnosis: Metal hypersensitivity Symptoms: Joint pain • swelling • instability Medication: — Clinical Procedure: Revision total knee arthroplasty Specialty: Orthopedics and Traumatology Objective: Unusual clinical course Background: Metal hypersensitivity is an uncommon complication after total knee arthroplasty (TKA) that can lead to significant functional impairment and aseptic prosthesis failure. Case Report: We describe a 70-year-old patient who presented with persistent pain, swelling, and instability 2 years after a primary TKA. The patient had a history of metal hypersensitivity following bilateral metal-on-metal total hip arthroplasty (THA) that was revised to ceramic-on-polyethylene implants. Knee radiographs showed severe osteolysis with implant loosening. Serum cobalt was elevated and serum chromium was significantly elevated, while joint aspiration and inflammatory marker levels ruled out a periprosthetic infection. Revision TKA was performed, with intraoperative tissue pathology and postoperative leukocyte transformation testing confirming metal hypersensitivity as the cause for aseptic implant failure. Conclusions: This case report demonstrates the clinical and laboratory signs that suggest metal hypersensitivity in total knee arthroplasty and the potential for joint function restoration with revision surgery. PMID:26278890

  9. Serum Metal Ions with a Titanium Modular Neck Total Hip Replacement System.

    PubMed

    Gofton, Wade; Beaule, Paul E

    2015-10-01

    The goal of this study is to evaluate serum levels of chromium (Cr), cobalt (Co), and titanium (Ti) within the first two years following total hip arthroplasty using a Ti modular neck system. Twenty-five patients were randomized to a metal-on-metal (MoM) bearing with an all CoCr shell, and the remaining 25 received a metal-on-polyethylene (MoP) with a Ti shell. Serum levels demonstrated increases for Cr, Co, and Ti at 1 year (P < .001). MoM had similar Ti levels to MoP hips at 1 year (P=0.11) but lower at 2 years (P=0.03). Results suggest that the passive corrosion (i.e., chemical, pitting, and crevice corrosion) of exposed non-articular metal surfaces may be a greater source of ions than the neck-stem or head-neck interfaces. PMID:26027522

  10. Optimal bearing surfaces for total hip replacement in the young patient: a meta-analysis.

    PubMed

    Shetty, Vijay; Shitole, Bhushan; Shetty, Gautam; Thakur, Harshad; Bhandari, Mohit

    2011-09-01

    Although there is general consensus about the efficacy of total hip replacement (THR) in young patients, the most appropriate bearings in young patients remain highly debated. The three most popular bearings in use include metal-on-polyethylene (MOP), metal-on-metal (MOM) and ceramic-on-ceramic (COC). We conducted a systematic review and meta-analysis of literature to summarise the best available evidence on relative success of the three most popular bearings used in THR in young active patients. Our findings support the use of MOM bearings in the management of the young arthritic hip. These findings, largely based upon observational studies, should be taken in the context of the limitations of such non-randomised study designs. PMID:20686893

  11. Hard-on-Hard Total Hip Impingement Causes Extreme Contact Stress Concentrations

    PubMed Central

    Elkins, Jacob M.; O’Brien, Megan K.; Stroud, Nicholas J.; Pedersen, Douglas R.; Callaghan, John J.

    2010-01-01

    Background Impingement events, in addition to their role immediately proximate to frank dislocation, hold the potential to damage new-generation hard-on-hard bearings as a result of the relatively unforgiving nature of the materials and designs. Because of the higher stiffness and tighter design tolerances of metal-on-metal and ceramic implants, surgical positioning plausibly has become even more important. Questions/purposes We asked (1) whether, and under what cup orientation conditions, hard-on-hard impingements might challenge implant material failure strength; and (2) whether particle generation propensity at impingement and egress sites would show similar dependence on cup orientation. Methods Realistic computational simulations were enabled by multistage finite element analyses, addressing both global construct motion and loading, and focal stress concentrations at neck impingement and rim egress sites. The global model, validated by a cadaveric simulation in a servohydraulic hip simulator, included both hardware components and advanced anisotropic capsule characterization. Parametric computational runs explored the effect of cup orientation for both ceramic-on-ceramic and metal-on-metal bearing couples for two distinct motion sequences associated with dislocation. Results Stress concentrations from impingement increased nearly linearly with increased cup tilt and with cup anteversion. In some situations, peak values of stress approached or exceeded 1 GPa, levels challenging the yield strength of cobalt-chromium implants, and potentially the fracture strength of ceramics. The tendency for impingement events to generate debris, indexed in terms of a new scraping severity metric, showed orientation dependences similar to that for bulk material failure. Conclusions Damage propensity arising from impingement events in hard total hip bearings is highly orientation-dependent. PMID:20953853

  12. Pseudotumor associated with metal-on-polyethylene total hip arthroplasty.

    PubMed

    Scully, William F; Teeny, Steven M

    2013-05-01

    This case report details the presentation, imaging results, and operative findings of a pseudotumor associated with a press-fit metal-on-polyethylene total hip arthroplasty (THA). An 80-year-old man presented approximately 7 years after undergoing THA with worsening right groin and lateral hip pain with an associated proximal thigh mass. Physical examination demonstrated a tender, large anterolateral thigh mass that was also evident on metal artifact reduction sequence magnetic resonance imaging.An exploratory operative procedure revealed extensive tissue necrosis involving nearly the entire hip capsule, short external rotators, and tendinous portion of the gluteus medius muscle. In addition, marked surface corrosion was discovered about the taper at the head-neck junction of the prosthetic femoral component and the trunnion within the femoral head. The press-fit THA components were solidly fixed. The metallic head was replaced with a ceramic component, and the polyethylene liner was exchanged. The patient had complete resolution of his preoperative symptoms but had persistent problems with dislocations.Although reports of pseudotumor and local soft tissue reactions associated with metal-on-metal THAs have become increasingly ubiquitous in the literature, similar reports involving metal-on-polyethylene THA implants are less common. PMID:23672921

  13. Presence of corrosion products and hypersensitivity-associated reactions in periprosthetic tissue after aseptic loosening of total hip replacements with metal bearing surfaces.

    PubMed

    Huber, Monika; Reinisch, Georg; Trettenhahn, Günter; Zweymüller, Karl; Lintner, Felix

    2009-01-01

    Aseptic loosening of articular implants is frequently associated with tissue reactions to wear particles. Some patients, who had received metal-on-metal articulations, present early symptoms including persistent pain and implant failure. These symptoms raise the suspicion about the development of an immunological response. Furthermore, the generation of rare corrosion products in association with metallic implants has been observed. Corrosion products are known to enhance third-body wear and contribute to the loss of the implant. The purpose of this study was to investigate periprosthetic tissue containing solid corrosion products after aseptic loosening of second-generation metal-on-metal total hip replacements made of low-carbon cobalt-chromium-molybdenum alloy for the presence of immunologically determined tissue changes. Periprosthetic tissue of 11 cases containing uncommon solid deposits was investigated by light microscopy. In order to confirm the presence of corrosion products, additional methods including scanning electron microscopy (SEM) investigation, energy dispersive X-ray (EDX) and Fourier transform infrared microspectroscopy (FTIR) analysis were used. All investigated cases revealed solid chromium orthophosphate corrosion products as well as metallic wear particles to a various extent. Moreover, various intense tissue reactions characteristic of immune response were observed in all cases. The simultaneous presence of corrosion products and hypersensitivity-associated tissue reaction indicates that a relationship between corrosion development and implant-related hypersensitivity may exist. PMID:18725188

  14. Alternative bearing surface options for revision total hip arthroplasty.

    PubMed

    Patel, Deepan; Parvizi, Javad; Sharkey, Peter F

    2011-01-01

    Despite the overall success of total hip arthroplasty (THA), there has been an increase in the rate of revision hip surgeries performed each year in the United States. These revision surgeries result in several billion dollars in health care costs. Bearing surface wear can result in the need for revision surgery through a variety of mechanisms. Many implant failures necessitating the need for revision surgeries occur secondary to dislocations, which are often related to prothesis wear and eventual loosening of the components. Wear also can lead to osteolysis and may play a role in aseptic loosening. Specific concerns regarding the wear rates of metal-on-polyethylene (the most common bearing surface) have encouraged the manufacture of newer polyethylene implants with improved wear properties, as well as alternative bearing surfaces. The goal is to improve the durability of revision implants and/or reduce the incidence of revision THAs. Revision arthroplasty involves using alternative surfaces, such as replacing the metal femoral head with a ceramic component or changing the entire prosthesis to a metal-on-metal or ceramic-on-ceramic articulation. It is important to review the characteristics of these alternative bearing surface options and their contributions to improved THA tribology and prolonged prosthesis longevity. The choice of a bearing surface for a revision THA should consider factors such as the patient's age and activity level, the cost of the implant, and both the surgeons' and patients' preferences. Although laboratory studies and small clinical trials have generated optimistic results for these alternative implants in vitro and in vivo, much still needs to be learned about the long-term performance of these materials in patients after total hip revision surgery. PMID:21553778

  15. Early surveillance of ceramic-on-metal total hip arthroplasty.

    PubMed

    Hill, J C; Diamond, O J; O'Brien, S; Boldt, J G; Stevenson, M; Beverland, D E

    2015-03-01

    Ceramic-on-metal (CoM) is a relatively new bearing combination for total hip arthroplasty (THA) with few reported outcomes. A total of 287 CoM THAs were carried out in 271 patients (mean age 55.6 years (20 to 77), 150 THAs in female patients, 137 in male) under the care of a single surgeon between October 2007 and October 2009. With the issues surrounding metal-on-metal bearings the decision was taken to review these patients between March and November 2011, at a mean follow-up of 34 months (23 to 45) and to record pain, outcome scores, radiological analysis and blood ion levels. The mean Oxford Hip Score was 19.2 (12 to 53), 254 patients with 268 hips (95%) had mild/very mild/no pain, the mean angle of inclination of the acetabular component was 44.8(o) (28(o) to 63(o)), 82 stems (29%) had evidence of radiolucent lines of > 1 mm in at least one Gruen zone and the median levels of cobalt and chromium ions in the blood were 0.83 ?g/L (0.24 ?g/L to 27.56 ?g/L) and 0.78 ?g/L (0.21 ?g/L to 8.84 ?g/L), respectively. The five-year survival rate is 96.9% (95% confidence interval 94.7% to 99%). Due to the presence of radiolucent lines and the higher than expected levels of metal ions in the blood, we would not recommend the use of CoM THA without further long-term follow-up. We plan to monitor all these patients regularly. PMID:25737511

  16. Serum Metal Ion Concentrations in Paediatric Patients following Total Knee Arthroplasty Using Megaprostheses

    PubMed Central

    Friesenbichler, Jörg; Sadoghi, Patrick; Maurer-Ertl, Werner; Szkandera, Joanna; Glehr, Mathias; Ogris, Kathrin; Wolf, Matthias; Weger, Christian; Leithner, Andreas

    2014-01-01

    The purpose of this study was to determine the concentrations of cobalt, chromium, and molybdenum in the serum of paediatric tumour patients after fixed hinge total knee arthroplasty. Further, these metal ion levels were compared with serum metal ion levels of patients with other orthopaedic devices such as hip and knee prostheses with metal-on-metal or metal-on-polyethylene articulation to find differences between anatomical locations, abrasion characteristics, and bearing surfaces. After an average follow-up of 108 months (range: 67 to 163) of 11 paediatric patients with fixed hinge total knee arthroplasty, the mean concentrations for Co and Cr were significantly increased while Mo was within the limits compared to the upper values from the reference laboratory. Furthermore, these serum concentrations were significantly higher compared to patients with a standard rotating hinge device (P = 0.002 and P < 0.001) and preoperative controls (P < 0.001). On the other hand, the serum levels of patients following MoM THA or rotating hinge arthroplasty using megaprostheses were higher. Therefore, periodic long-term follow-ups are recommended due to the rising concerns about systemic metal ion exposure in the literature. Upon the occurrence of adverse reactions to metal debris the revision of the fixed hinge implant should be considered. PMID:25276819

  17. Late Nontraumatic Dissociation of the Femoral Head and Trunnion in a Total Hip Arthroplasty

    PubMed Central

    Parker, Simon J. M.; Khan, Wasim; Mellor, Simon

    2015-01-01

    Background. Modular total hip arthroplasties are increasingly popular because customisation allows optimal restoration of patient biomechanics. However, the introduction of component interfaces provides greater opportunities for failure. We present a case of late nontraumatic dissociation of the head-neck interface, more than 10 years after insertion. Case Description. A 58-year-old woman had a left metal-on-metal total hip arthroplasty in 2002 for hip dysplasia. Following an uneventful 10-year period, she presented to hospital in severe pain after standing from a seated position, and radiographs demonstrated complete dissociation of the modular femoral head from the stem, with the femoral head remaining in its cup. There was no prior trauma or infection. Mild wear and metallosis were present on the articulating surface between the femoral head and trunnion. Soft tissues were unaffected. Discussion and Conclusions. This is the latest occurrence reported to date for nontraumatic component failure in such an implant by more than 7 years. The majority of cases occur in the context of dislocation and attempted closed reduction. We analyse and discuss possible mechanisms for failure, aiming to raise awareness of this potential complication and encouraging utmost care in component handling and insertion, as well as the long term follow-up of such patients. PMID:26078899

  18. Local and systemic toxicity of nanoscale debris particles in total hip arthroplasty.

    PubMed

    Polyzois, Ioannis; Nikolopoulos, Dimitrios; Michos, Ioannis; Patsouris, Efstratios; Theocharis, Stamatios

    2012-04-01

    Over the past 30?years joint replacement prostheses have been developed and refined to enhance durability and reproducibility. Total hip joint arthroplasty is being performed in an increasing number of younger patients; therefore orthopaedic surgeons seek implants with a longer life span. With regards to the progress of mechanical behaviour of the biomaterials used in an arthroplasty, little is known about the long-term biological effects of wear debris. Owing to the composition of the prostheses currently in use, systemic exposure to chromium (Cr), cobalt (Co), nickel (Ni) and aluminium (Al) alloys occurs as a result of the formation of metal wear nano-particles that are released both from metal-on-metal and polyethylene-on-metal bearings, resulting in a postoperative increase in metal ion levels at different organ sites. These particles circulate both locally and systemically, penetrate cell plasma membranes, bind to cellular proteins and enzymes and modulate cytokine expression. Their physiologic effects are poorly understood and their potential toxicity, hypersensitivity and carcinogenicity remain a cause for concern. In this article we will address the issue of whether these nanoscale degradation products are associated with adverse, clinically significant local or systemic toxicologic sequelae. PMID:22328167

  19. Expression of CD11c in periprosthetic tissues from failed total hip arthroplasties.

    PubMed

    Chamaon, Kathrin; Barber, Henriette; Awiszus, Friedemann; Feuerstein, Bernd; Lohmann, Christoph H

    2016-01-01

    In this work, we characterize integrin CD11c (?X2) expression in periprosthetic tissues of 45 hip revisions. Tissues were retrieved from 23 ceramic-on-ultra-high molecular weight polyethylene (UHMWPE), 20 metal-on-UHMWPE, and 2 metal-on-metal total hip arthroplasties (THAs). Capsular tissue retrieved during primary THA from 19 patients served as controls. We identified a system to identify important immunohistochemical markers that are expressed in aseptic loosening. We focused on CD11c, CD68 and CD14. We observed that the CD11c molecule possesses four different cellular patterns in the periprosthetic tissues. Three of them are associated with the occurrence of UHMWPE abrasive material. Double staining with CD14 and CD68 was used for a more detailed analysis of the CD11c expressing cells. We observed that all forms of CD11c positive cells are CD68 positive however, only two forms of CD11c expressing cells are positive for CD14. Providing cellular diversity of CD11c expression in periprosthetic tissue, our results provide a contribution toward the further understanding of different cellular mechanisms to foreign body material. 2015 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 104A: 136-144, 2016. PMID:26255872

  20. Total Artificial Heart

    MedlinePLUS

    ... the NHLBI on Twitter. What Is a Total Artificial Heart? A total artificial heart (TAH) is a ... outside power source. Normal Heart and CardioWest Total Artificial Heart Figure A shows the normal structure and ...

  1. Origin of Compact Triangular Islands in Metal-on-Metal Growth

    SciTech Connect

    Bogicevic, Alexander; Lundqvist, Bengt I.; Ovesson, Staffan

    1999-07-12

    The microscopic origin of compact triangular islands on close-packed surfaces is identified using kinetic Monte Carlo simulations with energy barriers obtained from density-functional calculations. In contrast to earlier accounts, corner diffusion anisotropy is found to control the shape of compact islands at intermediate temperatures. We rationalize the correlation between the orientation of dendrites grown at low temperatures and triangular islands grown at higher temperatures, and explain why in some systems dendrites grow fat before turning compact.

  2. New Insights into Hard Phases of CoCrMo Metal-on-Metal Hip Replacements

    PubMed Central

    Liao, Y.; Pourzal, R.; Stemmer, P.; Wimmer, M.A.; Jacobs, J.J.; Fischer, A.; Marks, L. D.

    2012-01-01

    The microstructural and mechanical properties of the hard phases in CoCrMo prosthetic alloys in both cast and wrought conditions were examined using transmission electron microscopy and nanoindentation. Besides the known carbides of M23C6-type (M=Cr, Mo, Co) and M6C-type which are formed by either eutectic solidification or precipitation, a new mixed-phase hard constituent has been found in the cast alloys, which is composed of ~100 nm fine grains. The nanosized grains were identified to be mostly of M23C6 type using nano-beam precession electron diffraction, and the chemical composition varied from grain to grain being either Cr- or Co-rich. In contrast, the carbides within the wrought alloy having the same M23C6 structure were homogeneous, which can be attributed to the repeated heating and deformation steps. Nanoindentation measurements showed that the hardness of the hard phase mixture in the cast specimen was ~15.7 GPa, while the M23C6 carbides in the wrought alloy were twice as hard (~30.7 GPa). The origin of the nanostructured hard phase mixture was found to be related to slow cooling during casting. Mixed hard phases were produced at a cooling rate of 0.2 C/s, whereas single phase carbides were formed at a cooling rate of 50 C/s. This is consistent with sluggish kinetics and rationalizes different and partly conflicting microstructural results in the literature, and could be a source of variations in the performance of prosthetic devices in-vivo. PMID:22659365

  3. Metallosis: A diagnosis not only in patients with metal-on-metal prostheses

    PubMed Central

    Oliveira, Catarina A.; Candelria, Isabel S.; Oliveira, Pedro B.; Figueiredo, Antonio; Caseiro-Alves, Filipe

    2014-01-01

    Although the real actual incidence of metallosis is unknown, it is described as a rare diagnosis with a 5% estimated incidence in the hip prosthetic replacements. The adoption of non-metallic articular prosthetic devices, made of polyethylene and ceramic, is the main reason to the diminishing number of reported cases. We present a case of metallosis with a clinical systemic presentation in a patient with a non-metallic hip prosthesis, which occurred due to a fracture of the acetabular liner component, leading to abnormal metalmetal contact. The metallic debris leads to a massive local and systemic release of cytokines. Revision is necessary whenever osteolysis and loosening of the prosthesis occur. Imaging evaluation, especially CT, has a central role in diagnosis and planning the surgical treatment.

  4. Information for Patients Who Have Metal-on-Metal Hip Implants

    MedlinePLUS

    ... can often lead manufacturers to improve an implant’s design and update device labeling for future patients. In ... State & Local Officials Consumers Health Professionals Science & Research Industry Scroll back to top Popular Content Home Latest ...

  5. Total Hip Replacement

    MedlinePLUS

    ... total hip replacement. According to the Agency for Healthcare Research and Quality, more than 300,000 total hip replacements are performed each year in the United States. Anatomy The hip is one of the body’s ...

  6. Total Energy Systems.

    ERIC Educational Resources Information Center

    Hick, Basil L.

    A total energy system is a means for providing all of the varied energy requirements for a total plant from a single fuel source. This report evaluates some of the factors which are related to the development and use of total energy systems. The factors include--(1) initial and ultimate size of plant, (2) type and source of fuel, (3)

  7. The Epidemiology and National Trends of Bearing Surface Usage in Primary Total Hip Arthroplasty in Korea

    PubMed Central

    Yoon, Pil Whan; Kim, Yunjung; Yoo, Seungmi; Lee, Sahnghoon; Kim, Hee Joong

    2016-01-01

    Background We analyzed the data for primary total hip arthroplasty (THA) in the Korean nationwide database to assess (1) the epidemiology and national trends of bearing surface usage in THAs and (2) the prevalence of each type of bearing surface according to age, gender, hospital type, primary payer, and hospital procedure volume. Methods A total of 30,881 THAs were analyzed using the Korean Health Insurance Review and Assessment Service database for 2007 through 2011. Bearing surfaces were sub-grouped according to device code for national health insurance claims and consisted of ceramic-on-ceramic (CoC), metal-on-polyethylene (MoP), ceramic-on-polyethylene (CoP), and metal-on-metal (MoM). The prevalence of each type of bearing surface was calculated and stratified by age, gender, hospital type, primary payer, and procedure volume of each hospital. Results CoC was the most frequently used bearing surface (76.7%), followed by MoP (11.9%), CoP (7.3%), and MoM (4.1%). The proportion of THAs using a CoC bearing surface increased steadily from 71.6% in 2007 to 81.4% in 2011, whereas the proportions using CoP, MoP, and MoM bearing surfaces decreased. The order of prevalence was identical to that in the general population regardless of age, gender, hospital type, primary payer, and hospital procedure volume. Conclusions The trends and epidemiology of bearing surface usage in THAs in Korea are different from those in other countries, and the CoC bearing surface is the most prevalent articulation. In future, the results of a large-scale study using nationwide data of THAs involving a CoC bearing surface will be reported in Korea. PMID:26929796

  8. Metal release and metal allergy after total hip replacement with resurfacing versus conventional hybrid prosthesis

    PubMed Central

    Gustafson, Klas; Jakobsen, Stig S; Lorenzen, Nina D; Thyssen, Jacob P; Johansen, Jeanne D; Bonefeld, Charlotte M; Stilling, Maiken; Baad-Hansen, Thomas; Søballe, Kjeld

    2014-01-01

    Background Metal-on-metal (MOM) total hip arthroplasties were reintroduced because of the problems with osteolysis and aseptic loosening related to polyethylene wear of early metal-on-polyethylene (MOP) arthroplasties. The volumetric wear rate has been greatly reduced with MOM arthroplasties; however, because of nano-size wear particles, the absolute number has been greatly increased. Thus, a source of metal ion exposure with the potential to sensitize patients is present. We hypothesized that higher amounts of wear particles result in increased release of metal ions and ultimately lead to an increased incidence of metal allergy. Methods 52 hips in 52 patients (median age 60 (51–64) years, 30 women) were randomized to either a MOM hip resurfacing system (ReCap) or a standard MOP total hip arthoplasty (Mallory Head/Exeter). Spot urine samples were collected preoperatively, postoperatively, after 3 months, and after 1, 2, and 5 years and tested with inductively coupled plasma-sector field mass spectrometry. After 5 years, hypersensitivity to metals was evaluated by patch testing and lymphocyte transformation assay. In addition, the patients answered a questionnaire about hypersensitivity. Results A statistically significant 10- to 20-fold increase in urinary levels of cobalt and chromium was observed throughout the entire follow-up in the MOM group. The prevalence of metal allergy was similar between groups. Interpretation While we observed significantly increased levels of metal ions in the urine during the entire follow-up period, no difference in prevalence of metal allergy was observed in the MOM group. However, the effect of long-term metal exposure remains uncertain. PMID:24930546

  9. Total hip arthroplasty in the young: special emphasis on post-SCFE patients.

    PubMed

    Nelms, Nathaniel J; Lewallen, Laura W; McIntosh, Amy L; Sierra, Rafael J

    2013-01-01

    Slipped capital femoral epiphysis (SCFE) is a hip disorder of adolescence, which has the potential for profound implications into adulthood. SCFE patients are at risk of early joint degeneration and subsequent need for arthroplasty. The rate at which arthroplasty is required is not precisely known, but is estimated to be approximately 45% by 50 years after a slip. The femoral neck and shaft displace anteriorly and rotate externally relative to the femoral epiphysis, which remains fixed in the acetabulum. Stabilization of the physis is the goal of acute management. Despite such efforts, accelerated joint degeneration may occur over time. This progression is due to avascular necrosis, chondrolysis, or following years of femoroacetabular impingement. Total hip arthroplasty (THA) and total hip resurfacing (THR) are options for end-stage hip arthritis due to SCFE. THR is technically more challenging, with very limited ability to address deformity-related issues of impingement, decreased hip offset, and trochanteric malposition. THR, as in any metal on metal arthroplasty, may be associated with local metal sensitivity or systemic metal toxicity. Given the limited utility and potential risks, THR is currently not recommended in the majority of cases. THA, although historically demonstrating poor long-term implant performance in the young patient, has become a more reliable option recently. The potential benefits of THA are considerable, even for the young patient with end-stage hip degeneration. Certain cemented and many cementless stem designs show good long-term survival, as do current cementless cups. Advances in bearing surfaces promise to minimize wear and extend implant longevity. Ceramic on ceramic, metal on highly cross-linked polyethylene, and ceramic on highly cross-linked polyethylene bearing couples offer promise. PMID:23764787

  10. Enhanced wear and corrosion in modular tapers in total hip replacement is associated with the contact area and surface topography.

    PubMed

    Panagiotidou, Anna; Meswania, Jay; Hua, Jia; Muirhead-Allwood, Sarah; Hart, Alister; Blunn, Gordon

    2013-12-01

    Widespread concern exists about adverse tissue reactions after metal-on-metal (MoM) total hip replacement (THR). Concerns have also been expressed with wear and corrosion of taper junctions in THR. We report the effect of surface finish and contact area associated with a single combination of materials of modular tapers. In an in vitro test, we investigated the head/neck (CoCrMo/Ti) interface of modular THRs using commercially available heads. Wear and corrosion of taper surfaces was compared following a 10 million loading cycle. Surface parameters and profiles were measured before and after testing. Electrochemical static and dynamic corrosion tests were performed under loaded and non-loaded conditions. After the load test, the surface roughness parameters on the head taper were significantly increased where the head/neck contact area was reduced. Similarly, the surface roughness parameters on the head taper were significantly increased where rough neck tapers were used. Corrosion testing showed breaching of the passive film on the rough but not the smooth neck tapers. Thus, surface area and surface finish are important factors in wear and corrosion at modular interfaces. PMID:23966288

  11. National trends in primary total hip arthroplasty in extremely young patients: a focus on bearing surface usage.

    PubMed

    Rajaee, Sean S; Trofa, David; Matzkin, Elizabeth; Smith, Eric

    2012-12-01

    The purpose of this study was to present national trends in primary total hip arthroplasty (THA) and bearing surface usage for patients 30 years and younger. Using the Healthcare-Cost-and-Utilization-Project Nationwide Inpatient Sample for the years 2006 to 2009, 8919 primary THA discharges (4454 coded by bearing surface) were identified in patients 30 years and younger. The most commonly used bearing surface was metal-on-metal (MoM), representing 37.6% of cases, followed by ceramic-on-ceramic (CoC) (24.6%), metal-on-polyethylene (MoP) (22.1%) and ceramic-on-polyethylene (15.7%). From 2006 to 2009, the percentage of THAs that used hard-on-hard bearing surfaces decreased (MoM: 42.9%-29.4%; CoC: 34.0%-19.7%).This decrease in hard-on-hard bearing surface usage presents a challenge for surgeons treating young patients to find other acceptable durable bearings that do not have the potential problems associated with MoM or CoC. PMID:22658430

  12. Compatibility of the totally replaced hip. Reduction of wear by amorphous diamond coating.

    PubMed

    Santavirta, Seppo

    2003-12-01

    Particulate wear debris in totally replaced hips causes adverse local host reactions. The extreme form of such a reaction, aggressive granulomatosis, was found to be a distinct condition and different from simple aseptic loosening. Reactive and adaptive tissues around the totally replaced hip were made of proliferation of local fibroblast like cells and activated macrophages. Methylmethacrylate and high-molecular-weight polyethylene were shown to be essentially immunologically inert implant materials, but in small particulate form functioned as cellular irritants initiating local biological reactions leading to loosening of the implants. Chromium-cobalt-molybdenum is the most popular metallic implant material; it is hard and tough, and the bearings of this metal are partially self-polishing. In total hip implants, prerequisites for longevity of the replaced hip are good biocompatibility of the materials and sufficient tribological properties of the bearings. The third key issue is that the bearing must minimize frictional shear at the prosthetic bone-implant interface to be compatible with long-term survival. Some of the approaches to meet these demands are alumina-on-alumina and metal-on-metal designs, as well as the use of highly crosslinked polyethylene for the acetabular component. In order to avoid the wear-based deleterious properties of the conventional total hip prosthesis materials or coatings, the present work included biological and tribological testing of amorphous diamond. Previous experiments had demonstrated that a high adhesion of tetrahedral amorphous carbon coatings to a substrate can be achieved by using mixing layers or interlayers. Amorphous diamond was found to be biologically inert, and simulator testing indicated excellent wear properties for conventional total hip prostheses, in which either the ball or both bearing surfaces were coated with hydrogen-free tetrahedral amorphous diamond films. Simulator testing with such total hip prostheses showed no measurable wear or detectable delamination after 15,000,000 test cycles corresponding to 15 years of clinical use. The present work clearly shows that wear is one of the basic problems with totally replaced hips. Diamond coating of the bearing surfaces appears to be an attractive solution to improve longevity of the totally replaced hip. PMID:14768485

  13. Parallel Total Energy

    Energy Science and Technology Software Center (ESTSC)

    2004-10-21

    This is a total energy electronic structure code using Local Density Approximation (LDA) of the density funtional theory. It uses the plane wave as the wave function basis set. It can sue both the norm conserving pseudopotentials and the ultra soft pseudopotentials. It can relax the atomic positions according to the total energy. It is a parallel code using MP1.

  14. Total Quality Leadership

    NASA Technical Reports Server (NTRS)

    1991-01-01

    More than 750 NASA, government, contractor, and academic representatives attended the Seventh Annual NASA/Contractors Conference on Quality and Productivity. The panel presentations and Keynote speeches revolving around the theme of total quality leadership provided a solid base of understanding of the importance, benefits, and principles of total quality management (TQM). The presentations from the conference are summarized.

  15. Total financial management.

    PubMed

    Katz, R W

    1991-01-01

    Total financial management is a program designed by author Robert Katz, M.S., C.P.A., which says that by managing from the top down, the physician/administrator team can regain control of the practice and its major financial centers. His article describes the two-phased approach to total financial management. PMID:10114600

  16. Total hip arthroplasty.

    PubMed Central

    Siopack, J S; Jergesen, H E

    1995-01-01

    Total hip arthroplasty, or surgical replacement of the hip joint with an artificial prosthesis, is a reconstructive procedure that has improved the management of those diseases of the hip joint that have responded poorly to conventional medical therapy. In this review we briefly summarize the evolution of total hip arthroplasty, the design and development of prosthetic hip components, and the current clinical indications for this procedure. The possible complications of total hip arthroplasty, its clinical performance over time, and future directions in hip replacement surgery are also discussed. Images PMID:7725707

  17. Total Water Management - slides

    EPA Science Inventory

    Total Water Management (TWM) examines urban water systems in an interconnected manner. It encompasses reducing water demands, increasing water recycling and reuse, creating water supply assets from stormwater management, matching water quality to end-use needs, and achieving envi...

  18. Total proctocolectomy with ileostomy

    MedlinePLUS

    Total proctocolectomy with ileostomy is surgery to remove all of the colon (large intestine) and rectum. ... Mahmoud N, Maron DJ, Ross HM, Rombeau J. Colon and rectum. In: Townsend ... . 19th ed. Philadelphia, PA: Elsevier Saunders; 2007:chap ...

  19. Total parenteral nutrition - infants

    MedlinePLUS

    Total parenteral nutrition (TPN) is a method of feeding that bypasses the gastrointestinal tract. Fluids are given into a vein to ... babies. It can provide a better level of nutrition than regular intravenous (IV) feedings, which provide only ...

  20. Total lymphoid irradiation

    SciTech Connect

    Sutherland, D.E.; Ferguson, R.M.; Simmons, R.L.; Kim, T.H.; Slavin, S.; Najarian, J.S.

    1983-05-01

    Total lymphoid irradiation by itself can produce sufficient immunosuppression to prolong the survival of a variety of organ allografts in experimental animals. The degree of prolongation is dose-dependent and is limited by the toxicity that occurs with higher doses. Total lymphoid irradiation is more effective before transplantation than after, but when used after transplantation can be combined with pharmacologic immunosuppression to achieve a positive effect. In some animal models, total lymphoid irradiation induces an environment in which fully allogeneic bone marrow will engraft and induce permanent chimerism in the recipients who are then tolerant to organ allografts from the donor strain. If total lymphoid irradiation is ever to have clinical applicability on a large scale, it would seem that it would have to be under circumstances in which tolerance can be induced. However, in some animal models graft-versus-host disease occurs following bone marrow transplantation, and methods to obviate its occurrence probably will be needed if this approach is to be applied clinically. In recent years, patient and graft survival rates in renal allograft recipients treated with conventional immunosuppression have improved considerably, and thus the impetus to utilize total lymphoid irradiation for its immunosuppressive effect alone is less compelling. The future of total lymphoid irradiation probably lies in devising protocols in which maintenance immunosuppression can be eliminated, or nearly eliminated, altogether. Such protocols are effective in rodents. Whether they can be applied to clinical transplantation remains to be seen.

  1. Totally unimodular nets.

    PubMed

    Eon, Jean-Guillaume; Proserpio, Davide M; Blatov, Vladislav A

    2012-03-01

    p-Periodic nets can be derived from a voltage graph G with voltages in Z(p), the free abelian group of rank p, if the cyclomatic number ? of G is larger than p. Equivalently, one may describe a net by providing a set of (? - p) cycle vectors of G forming a basis of the subspace of the cycle space of G with zero net voltage. Let M be the matrix of this basis expressed in the edge basis of the 1-chain space of G. A net is called totally unimodular whenever every sub-determinant of M belongs to the set {-1, 0, 1}. Only a finite set of totally unimodular nets can be derived from some finite graph. It is shown that totally unimodular nets are stable under the operation of edge-lattice deletion in a sense that makes them comparable to minimal nets. An algorithm for the complete determination of totally unimodular nets derived from some finite graph is presented. As an application, the full list of totally unimodular nets derived from graphs of cyclomatic numbers 3 and 4, without bridges, is given. It is shown that many totally unimodular nets frequently occur in crystal structures. PMID:22338663

  2. Mixing of components from different manufacturers in total hip arthroplasty: prevalence and comparative outcomes

    PubMed Central

    Tucker, Keith; Pickford, Martin; Newell, Claire; Howard, Peter; Hunt, Linda P; Blom, Ashley W

    2015-01-01

    Background and purpose There have recently been highly publicized examples of suboptimal outcomes with some newer implant designs used for total hip replacement. This has led to calls for tighter regulation. However, surgeons do not always adhere to the regulations already in place and often use implants from different manufacturers together to replace a hip, which is against the recommendations of the Medicines and Healthcare Products Regulatory Agency (MHRA) and the directions of the manufacturers. Patients and methods We used data from the National Joint Registry of England and Wales (NJR) to investigate this practice. Results Mixing of components was common, and we identified over 90,000 cases recorded between 2003 and 2013. In the majority of these cases (48,156), stems and heads from one manufacturer were mixed with polyethylene cemented cups from another manufacturer. When using a cemented stem and a polyethylene cup, mixing of stems from one manufacturer with cups from another was associated with a lower revision rate. At 8 years, the cumulative percentage of revisions was 1.9% (95% CI: 1.72.1) in the mixed group as compared to 2.4% (2.32.5) in the matched group (p = 0.001). Mixing of heads from one manufacturer with stems from another was associated with a higher revision rate (p < 0.001). In hip replacements with ceramic-on-ceramic or metal-on-metal bearings, mixing of stems, heads, and cups from different manufacturers was associated with similar revision rates (p > 0.05). Interpretation Mixing of components from different manufacturers is a common practice, despite the fact that it goes against regulatory guidance. However, it is not associated with increased revision rates unless heads and stems from different manufacturers are used together. PMID:26201845

  3. Mixing of components from different manufacturers in total hip arthroplasty: prevalence and comparative outcomes.

    PubMed

    Tucker, Keith; Pickford, Martin; Newell, Claire; Howard, Peter; Hunt, Linda P; Blom, Ashley W

    2015-12-01

    Background and purpose - There have recently been highly publicized examples of suboptimal outcomes with some newer implant designs used for total hip replacement. This has led to calls for tighter regulation. However, surgeons do not always adhere to the regulations already in place and often use implants from different manufacturers together to replace a hip, which is against the recommendations of the Medicines and Healthcare Products Regulatory Agency (MHRA) and the directions of the manufacturers. Patients and methods - We used data from the National Joint Registry of England and Wales (NJR) to investigate this practice. Results - Mixing of components was common, and we identified over 90,000 cases recorded between 2003 and 2013. In the majority of these cases (48,156), stems and heads from one manufacturer were mixed with polyethylene cemented cups from another manufacturer. When using a cemented stem and a polyethylene cup, mixing of stems from one manufacturer with cups from another was associated with a lower revision rate. At 8 years, the cumulative percentage of revisions was 1.9% (95% CI: 1.7-2.1) in the mixed group as compared to 2.4% (2.3-2.5) in the matched group (p = 0.001). Mixing of heads from one manufacturer with stems from another was associated with a higher revision rate (p < 0.001). In hip replacements with ceramic-on-ceramic or metal-on-metal bearings, mixing of stems, heads, and cups from different manufacturers was associated with similar revision rates (p > 0.05). Interpretation - Mixing of components from different manufacturers is a common practice, despite the fact that it goes against regulatory guidance. However, it is not associated with increased revision rates unless heads and stems from different manufacturers are used together. PMID:26201845

  4. Ceramic-on-metal for total hip replacement: mixing and matching can lead to high wear.

    PubMed

    Affatato, Saverio; Spinelli, Michele; Zavalloni, Mara; Traina, Francesco; Carmignato, Simone; Toni, Aldo

    2010-04-01

    Ceramic-on-ceramic and metal-on-metal bearing surfaces are often employed for total hip replacement because of their resistance to wear. However, they have some limits: brittleness is a major concern for ceramic, and ion release is a drawback for metal. To reduce the effect of these limitations, a hybrid coupling of ceramic-on-metal has been proposed. The theoretical advantage of this new coupling might lead orthopedic surgeons to use it indiscriminately. We asked whether the wear rate of this innovative solution was comparable with that of ceramic-on-ceramic, which is considered to be the gold standard for wear resistance. In a hip simulator study, we tested the wear pattern of a hybrid ceramic-on-metal coupling supplied by the same distributor; in particular, three different configurations were tested for 5 million cycles: 36-mm ceramic-on-ceramic, 32-mm and 36-mm ceramic-on-metal. These combinations were gravimetrically and geometrically evaluated. After 5 million cycles, the volumetric loss for the metal acetabular cups (Phi 36-mm) was 20-fold greater than that of the ceramic cups of the same size (Phi 36-mm); a volumetric loss of 4.35 mm(3) and 0.26 mm(3) was observed, respectively, for ceramic-on-metal and ceramic-on-ceramic combinations. Significant statistical differences were observed between all 36-mm different combinations (P < 0.0001). The increased diameter of the 36-mm ceramic-on-metal configuration resulted in a lower volumetric loss compared with that of the 32-mm ceramic-on-metal configuration. Our findings showed an increase in wear for the proposed hybrid specimens with respect to that of the ceramic-on-ceramic ones. This confirms that even in the case of ceramic-on-metal bearings, mixing and matching could not prove effective wear behavior, not even comparable with that of the ceramic-on-ceramic gold standard. PMID:20420614

  5. Total Energy Monitor

    SciTech Connect

    Friedrich, S

    2008-08-11

    The total energy monitor (TE) is a thermal sensor that determines the total energy of each FEL pulse based on the temperature rise induced in a silicon wafer upon absorption of the FEL. The TE provides a destructive measurement of the FEL pulse energy in real-time on a pulse-by-pulse basis. As a thermal detector, the TE is expected to suffer least from ultra-fast non-linear effects and to be easy to calibrate. It will therefore primarily be used to cross-calibrate other detectors such as the Gas Detector or the Direct Imager during LCLS commissioning. This document describes the design of the TE and summarizes the considerations and calculations that have led to it. This document summarizes the physics behind the operation of the Total Energy Monitor at LCLS and derives associated engineering specifications.

  6. Total Immersion Camping.

    ERIC Educational Resources Information Center

    Conklin, Mildred; Murphy, Stephen

    A total immersion program at North Rose-Wolcott High School, Wolcott, New York, involves speaking in the target language over a period of hours or days, the assistance of at least one fluent speaker for each six students, and a planned schedule of activities. Programs have varied from activities at the home of a teacher, all-day interaction at

  7. "Total Deposition (TDEP) Maps"

    EPA Science Inventory

    The presentation provides an update on the use of a hybrid methodology that relies on measured values from national monitoring networks and modeled values from CMAQ to produce of maps of total deposition for use in critical loads and other ecological assessments. Additionally, c...

  8. CSF total protein

    MedlinePLUS

    CSF total protein is a test to determine the amount of protein in your spinal fluid, also called cerebrospinal fluid (CSF). ... The normal protein range varies from lab to lab, but is typically about 15 to 60 mg/dL. Note: mg/dL = ...

  9. Total Quality Management Seminar.

    ERIC Educational Resources Information Center

    Massachusetts Career Development Inst., Springfield.

    This booklet is one of six texts from a workplace literacy curriculum designed to assist learners in facing the increased demands of the workplace. The booklet contains seven sections that cover the following topics: (1) meaning of total quality management (TQM); (2) the customer; (3) the organization's culture; (4) comparison of management

  10. Total Water Management

    EPA Science Inventory

    This project will investigate total water management (TWM) as a way of improving water resource management and reducing waste streams. This project will also improve management of potable water, wastewater and wet-weather flow through combined management, reuse and recycling wil...

  11. Total Precipitable Water

    SciTech Connect

    2012-01-01

    The simulation was performed on 64K cores of Intrepid, running at 0.25 simulated-years-per-day and taking 25 million core-hours. This is the first simulation using both the CAM5 physics and the highly scalable spectral element dynamical core. The animation of Total Precipitable Water clearly shows hurricanes developing in the Atlantic and Pacific.

  12. Estuarine Total Ecosystem Metabolism

    EPA Science Inventory

    Total ecosystem metabolism (TEM), both as discrete measurements and as a theoretical concept, has an important history in ecosystem ecology, particularly in estuaries. Some of the earliest ecological studies were developed to determine how energy flowed through an ecosystem and w...

  13. TOTAL DIET STUDY

    EPA Science Inventory

    The Total Diet Study (TDS), sometimes called the Market Basket Study, is an ongoing FDA program that determines levels of various pesticide residues, contaminants, and nutrients in foods, for the purpose of estimating intakes of these substances in representative diets of specifi...

  14. Total Water Management - Report

    EPA Science Inventory

    There is a growing need for urban water managers to take a more holistic view of their water resource systems as population growth, urbanization, and current operations put different stresses on the environment and urban infrastructure. Total Water Management (TWM) is an approac...

  15. Head size and dislocation rate in primary total hip arthroplasty

    PubMed Central

    Singh, Somesh P; Bhalodiya, Haresh P

    2013-01-01

    Background: Dislocation after total hip arthroplasty (THA) has a multifactorial etiology with variables such as surgical approach, component orientation and position, type of cup, stem and head size. Review of the literature regarding the relationship of head size and dislocation rate in THA is suggestive that large femoral head size is associated with lower dislocation rate after THA. However, limited data is available as a proof of this hypothesis. The purpose of this study was to determine that the use of large head size would lead to a decreased incidence of dislocations following THA. Materials and Methods: 317 primary THAs were performed using the posterolateral approach with posterior soft-tissue repair between January 2006 and December 2009. Cases were divided into two groups (A and B). Femoral head diameter size 36 mm was used in 163 THA in group A and 28 mm in 154 THA in group B. Average period of followup being 2 years (6 month to 4 years). Patients were routinely followed at definite intervals and were specifically assessed for dislocation. Results: One or more dislocations occurred in 11 out of 317 hips with the overall rate of dislocation being 3.47%. Dislocation rate was 0.6% in 36 mm head size and 6.49% with 28 mm head size (P value is 0.0107). Keeping the stem design variable as a constant, the difference in the rate of dislocation between the two groups was again found to be statistically significant for both un-cemented and cemented stem. Conclusion: Dislocation rate decreased significantly as the size of the head increased in primary THA. However, longer followup is necessary as rate of dislocation or in vivo highly cross linked poly failure or fracture may increase in future affecting the rate of dislocations in primary THA. PMID:24133302

  16. Totally parallel multilevel algorithms

    NASA Technical Reports Server (NTRS)

    Frederickson, Paul O.

    1988-01-01

    Four totally parallel algorithms for the solution of a sparse linear system have common characteristics which become quite apparent when they are implemented on a highly parallel hypercube such as the CM2. These four algorithms are Parallel Superconvergent Multigrid (PSMG) of Frederickson and McBryan, Robust Multigrid (RMG) of Hackbusch, the FFT based Spectral Algorithm, and Parallel Cyclic Reduction. In fact, all four can be formulated as particular cases of the same totally parallel multilevel algorithm, which are referred to as TPMA. In certain cases the spectral radius of TPMA is zero, and it is recognized to be a direct algorithm. In many other cases the spectral radius, although not zero, is small enough that a single iteration per timestep keeps the local error within the required tolerance.

  17. Total synthesis of clostrubin

    PubMed Central

    Yang, Ming; Li, Jian; Li, Ang

    2015-01-01

    Clostrubin is a potent antibiotic against methicillin- and vancomycin-resistant bacteria that was isolated from a strictly anaerobic bacterium Clostridium beijerinckii in 2014. This polyphenol possesses a fully substituted arene moiety on its pentacyclic scaffold, which poses a considerable challenge for chemical synthesis. Here we report the first total synthesis of clostrubin in nine steps (the longest linear sequence). A desymmetrization strategy is exploited based on the inherent structural feature of the natural product. Barton–Kellogg olefination forges the two segments together to form a tetrasubstituted alkene. A photo-induced 6π electrocyclization followed by spontaneous aromatization constructs the hexasubstituted B ring at a late stage. In total, 200 mg of clostrubin are delivered through this approach. PMID:25759087

  18. The Total Library *

    PubMed Central

    Annan, Gertrude L.

    1968-01-01

    Changing functions and techniques of today's libraries have led to questioning the very substance of the library of the future. Ralph Shaw points out that the total library must be a living force for the enrichment of mankind. The Medical Research Library of Brooklyn at its very inauguration is uniquely prepared and equipped to work toward that goal. It imaginatively serves the needs of the immediate area by generous sharing of resources, use of its computerized program, and participation in a state-wide system. The large collection of the Academy of Medicine of Brooklyn offers thousands of volumes for the historian, both great works as highlights of medical achievements and more modest contributions of both early and recent date. The total library must serve as an intellectual resource, as well as a mechanism for the rapid transfer of current information. PMID:5644795

  19. Total synthesis of brazilin.

    PubMed

    Jung, Youngeun; Kim, Ikyon

    2015-02-01

    Described herein is a highly efficient total synthesis of brazilin from commercially available starting materials in 9 steps with 70% overall yield. Mitsunobu coupling followed by In(III)-catalyzed alkyne-aldehyde metathesis allowed for rapid construction of brazilin core skeleton in quantitative yield. Subsequent modulation of oxidation levels and acid-catalyzed cyclization led to the trimethyl ether of brazilin. Asymmetric dihydroxylation of the key intermediate was also demonstrated, which would permit asymmetric access to (+)-brazilin. PMID:25562504

  20. Physician Update: Total Health

    PubMed Central

    Tuso, Phillip

    2014-01-01

    As an integrated prepaid health care system, Kaiser Permanente (KP) is in a unique position to demonstrate that affordability in health care can be achieved by disease prevention. During the past decade, KP has significantly improved the quality care outcomes of its members with preventable diseases. However, because of an increase in the incidence of preventable disease, and the potential long-term and short-term costs associated with the treatment of preventable disease, KP has developed a new strategy called Total Health to meet the current and future needs of its patients. Total Health means healthy people in healthy communities. KPs strategic vision is to be a leader in Total Health by making lives better. KP hopes to make lives better by 1) measuring vital signs of health, 2) promoting healthy behaviors, 3) monitoring disease incidence, 4) spreading leading practices, and 5) creating healthy environments with our community partners. Best practices, spread to the communities we serve, will make health care more affordable, prevent preventable diseases, and save lives. PMID:24694316

  1. Total Synthesis of ()-Strictamine.

    PubMed

    Ren, Weiwu; Wang, Qian; Zhu, Jieping

    2016-03-01

    The total synthesis of strictamine has been achieved in nine steps from a known enol triflate. Characteristic features of our approach included: a)?creation of a C7 all-carbon quaternary stereocenter at an early synthetic stage; b)?use of an N,N-dimethyl tertiary amine as a surrogate of the primary amine for the rapid build-up of a functionalized 2-azabicyclo[3,3,1]nonan-9-one skeleton (achieved by using a reaction sequence of ?-bromination of the ketone, followed by a stereoconvergent intramolecular nucleophilic substitution reaction); and c)?a late-stage construction of the indolenine unit. PMID:26845231

  2. Total quality assurance

    NASA Astrophysics Data System (ADS)

    Louzon, E.

    1989-12-01

    Quality, cost, and schedule are three factors affecting the competitiveness of a company; they require balancing so that products of acceptable quality are delivered, on time and at a competitive cost. Quality costs comprise investment in quality maintenance and failure costs which arise from failure to maintain standards. The basic principle for achieving the required quality at minimum cost is that of prevention of failures, etc., through production control, attention to manufacturing practices, and appropriate management and training. Total quality control involves attention to the product throughout its life cycle, including in-service performance evaluation, servicing, and maintenance.

  3. Total Synthesis of (-)-Exiguolide.

    PubMed

    Zhang, Zhigao; Xie, Hengmu; Li, Hongze; Gao, Lu; Song, Zhenlei

    2015-10-01

    A concise total synthesis of (-)-exiguolide has been completed in an overall 2.8% yield over 20 steps in the longest linear path. The key strategies involve (1) Prins cyclization/homobromination of dienyl alcohol with the B ring-substituted aldehyde, prepared by Prins cyclization/bromination, to construct the A ring with excellent cis-Z stereochemical control and (2) an unusual side chain installation/macrocyclization strategy featuring Sonogashira cross-coupling followed by a ring-closing metathesis reaction to deliver the target. PMID:26371396

  4. Total photoabsorption in nuclei

    SciTech Connect

    Bianchi, N.

    1992-06-01

    The Frascati-Genova collaboration proposes to measure the total photonuclear cross section on a wide range of nuclei between 500 MeV and 2 GeV, to obtain informations on the interaction of baryon resonances with nucleons and on the onset of the shadowing effect. The experiment could be performed in the Hall B as soon as the tagging facility will be ready and before the end of the installation of the CLAS spectrometer. The requirements for the photon beam, like maximum energy, intensity and beam definition, are not so strong so that the experiment would also be a good first test of the tagged photon facility.

  5. Total synthesis of (+)-crotogoudin.

    PubMed

    Breitler, Simon; Carreira, Erick M

    2013-10-11

    Fellowship of the ring: The first total synthesis of (+)-crotogoudin, a 3,4-seco-atisane diterpenoid natural product, is reported. Asymmetric access to the bicyclo[2.2.2]octane core is achieved through a desymmetrization of a meso-diketone with baker's yeast (LG=leaving group, PG=protecting group). A SmI2 -induced radical cyclopropane-opening/annulation/elimination cascade affords the suitably decorated tetracyclic structure of (+)-crotogoudin. The synthesis led to revision of the reported optical rotation of the natural product and to assignment of its absolute configuration as an ent-atisane (5R,10R). PMID:24039092

  6. Total syntheses of tubulysins.

    PubMed

    Shibue, Taku; Hirai, Toshihiro; Okamoto, Iwao; Morita, Nobuyoshi; Masu, Hyuma; Azumaya, Isao; Tamura, Osamu

    2010-10-11

    The total syntheses of tetrapeptides tubulysins?D (1?b), U (1?c), and V (1?d), which are potent tubulin polymerization inhibitors, are described. The synthesis of Tuv (2), an unusual amino acid constituent of tubulysins, includes an 1,3-dipolar cycloaddition reaction of chiral nitrone D-6 derived from D-gulose with N-acryloyl camphor sultam (-)-9 employing the double asymmetric induction, whereas the synthesis of Tup (20), another unusual amino acid, involves a stereoselective Evans aldol reaction of (Z)-boron enolate generated from (S)-4-isopropyl-3-propionyl-2-oxazolidinone with N-protected phenylalaninal and a subsequent Barton deoxygenation protocol. We accomplished the total syntheses of tubulysins?U (1?c) and V (1?d) by using these methodologies, in which the isoxazolidine ring was used as the effective protective group for ?-amido alcohol functionality. Furthermore, to understand the structure-activity relationship of tubulysins, we synthesized tubulysin?D (1?b) and cyclo-tubulysin?D (1?e) from 2-Me and 20, and ent-tubulysin?D (ent-1?d) from ent-2-Me and ent-20, respectively. The preliminary results regarding their biological activities are also reported. PMID:20734394

  7. Total disk arthroplasty.

    PubMed

    Lin, Eric L; Wang, Jeffrey C

    2006-12-01

    Spinal fusion remains the gold standard for surgical management of instability and mechanical low back or neck pain. However, even in carefully selected patients, successful clinical results can be difficult to achieve. Reasons for failure include pseudarthrosis and adjacent spine segment disease. The theoretic advantages of removing the painful disk while preserving motion have led to increasing interest in total disk arthroplasty. Although disk replacements have been implanted in Europe for decades, the procedure is relatively new in the United States. Recently, two artificial disks for symptomatic lumbar degenerative disk disease have been approved by the US Food and Drug Administration; several others are undergoing clinical trials. Short-term studies demonstrate similar clinical improvements for both disk replacements and fusion procedures at up to 2-year follow-up. Issues requiring further research include optimal design specifications, potential complications, and appropriate patient selection. Consequently, the long-term benefit of total disk arthroplasty over fusion for the treatment of axial low back or neck pain remains to be determined. PMID:17148618

  8. Totally frictionless magnetic bearing

    NASA Astrophysics Data System (ADS)

    Dodakian, Wayne; Bulman, John

    2000-11-01

    A totally frictionless magnetic bearing has been developed which supports a rotor in a contactless manner. The rotor is held in a magnetic potential well via repulsive forces only. Vertical and lateral restoring forces are provided to the rotor passively via permanent magnets in such an arrangement so as to support the weight of the rotor and provide it with a high degree of lateral stability. Axial stability of the rotor is provided by the use of an electromagnet which is controlled by a PID control loop. Information on the axial position of the rotor is provided to the circuit by use of an infrared LED and IR phototransistor. To prevent unwanted oscillations of the rotors axial position from occurring, an oscillation sensor in the form of an inductive pick-up coil of high impedance provides signals to the oscillation sensing portion of the circuit, which in turn feeds the oscillation dampening circuit. The use of only repulsive forces in stabilizing the rotor means that there will be no eddy current losses or hysterisis losses. Such a frictionless magnetic bearing can, for example be used in rotational oscillation experiments and ultra low loss watt-hour meters, which are of great importance to utility companies. When properly tuned, the total power requirements of the circuit is a mere 40mW, which is less than the 80 mW used by present day watt-hour meters.

  9. TOTAL user manual

    NASA Technical Reports Server (NTRS)

    Johnson, Sally C.; Boerschlein, David P.

    1994-01-01

    Semi-Markov models can be used to analyze the reliability of virtually any fault-tolerant system. However, the process of delineating all of the states and transitions in the model of a complex system can be devastatingly tedious and error-prone. Even with tools such as the Abstract Semi-Markov Specification Interface to the SURE Tool (ASSIST), the user must describe a system by specifying the rules governing the behavior of the system in order to generate the model. With the Table Oriented Translator to the ASSIST Language (TOTAL), the user can specify the components of a typical system and their attributes in the form of a table. The conditions that lead to system failure are also listed in a tabular form. The user can also abstractly specify dependencies with causes and effects. The level of information required is appropriate for system designers with little or no background in the details of reliability calculations. A menu-driven interface guides the user through the system description process, and the program updates the tables as new information is entered. The TOTAL program automatically generates an ASSIST input description to match the system description.

  10. Anisotropic Total Variation Filtering

    SciTech Connect

    Grasmair, Markus; Lenzen, Frank

    2010-12-15

    Total variation regularization and anisotropic filtering have been established as standard methods for image denoising because of their ability to detect and keep prominent edges in the data. Both methods, however, introduce artifacts: In the case of anisotropic filtering, the preservation of edges comes at the cost of the creation of additional structures out of noise; total variation regularization, on the other hand, suffers from the stair-casing effect, which leads to gradual contrast changes in homogeneous objects, especially near curved edges and corners. In order to circumvent these drawbacks, we propose to combine the two regularization techniques. To that end we replace the isotropic TV semi-norm by an anisotropic term that mirrors the directional structure of either the noisy original data or the smoothed image. We provide a detailed existence theory for our regularization method by using the concept of relaxation. The numerical examples concluding the paper show that the proposed introduction of an anisotropy to TV regularization indeed leads to improved denoising: the stair-casing effect is reduced while at the same time the creation of artifacts is suppressed.

  11. Postoperative total parenteral nutrition.

    PubMed

    Waitzberg, D L; Plopper, C; Terra, R M

    1999-06-01

    Surgical trauma induces complex physiologic changes that lead to catabolism and loss of body cell mass. This reaction is usually mild but can be exacerbated by previous malnutrition and postoperative complications. To avoid severe metabolic distress, nutritional therapy may be prescribed, using the enteral route whenever possible. Postoperative total parenteral nutrition (TPN) is indicated for patients already receiving TPN preoperatively, those severely malnourished prior to major surgery, those unable to eat satisfactorily for 7 days, or patients presenting with severe complications. Postoperative TPN should last for at least 7 days. The total energy requirements are between 30 and 35 kcal/kg/day. About 50% to 70% should be provided in the form of carbohydrates, and 20% to 30% in the form of lipids. The optimal input rates for glucose and lipids are 4 to 5 g/kg/day and 80 mg/kg/hr, respectively. The ideal nitrogen administration is 250 to 300 mg/kg/day, and the optimal calorie/nitrogen ratio is 150 to 200. Some specific amino acids can be added as intravenous dipeptides. An adequate follow-up must include clinical and biochemical parameters. Several trials evaluated the impact of TPN in postoperative patients, but further well designed, controlled clinical trials are still necessary to address a great number of unanswered questions. PMID:10227924

  12. Total Synthesis of Crotophorbolone.

    PubMed

    Asaba, Taro; Katoh, Yuki; Urabe, Daisuke; Inoue, Masayuki

    2015-11-23

    The complex ABC-tricyclic structure of crotophorbolone, a derivative of the tigliane diterpenoids, was assembled by coupling of simple fragments. The six-membered C-ring fragment, having five contiguous stereocenters, was stereoselectively constructed from (R)-carvone. After attachment of the five-membered A-ring through the ?-allyl Stille coupling reaction, the ?-alkoxy bridgehead radical reaction effected the endo-cyclization of the seven-membered B-ring by forming the sterically congested bond at C9 and C10 stereospecifically and stereoselectively, respectively. Finally, the functional groups on the 5/7/6-membered ring system were manipulated by rhodium-catalyzed C2?olefin isomerization, C13?decarboxylative oxidation, and C4?hydroxylation, thus completing the first total synthesis of crotophorbolone. PMID:26493044

  13. Total ankle joint replacement.

    PubMed

    2016-02-01

    Ankle arthritis results in a stiff and painful ankle and can be a major cause of disability.(1) For people with end-stage ankle arthritis, arthrodesis (ankle fusion) is effective at reducing pain in the shorter term, but results in a fixed joint, and over time the loss of mobility places stress on other joints in the foot that may lead to arthritis, pain and dysfunction.(2) Another option is to perform a total ankle joint replacement, with the aim of giving the patient a mobile and pain-free ankle. In this article we review the efficacy of this procedure, including how it compares to ankle arthrodesis, and consider the indications and complications. PMID:26868932

  14. Cervical total disc arthroplasty.

    PubMed

    Basho, Rahul; Hood, Kenneth A

    2012-06-01

    Symptomatic adjacent segment degeneration of the cervical spine remains problematic for patients and surgeons alike. Despite advances in surgical techniques and instrumentation, the solution remains elusive. Spurred by the success of total joint arthroplasty in hips and knees, surgeons and industry have turned to motion preservation devices in the cervical spine. By preserving motion at the diseased level, the hope is that adjacent segment degeneration can be prevented. Multiple cervical disc arthroplasty devices have come onto the market and completed Food and Drug Administration Investigational Device Exemption trials. Though some of the early results demonstrate equivalency of arthroplasty to fusion, compelling evidence of benefits in terms of symptomatic adjacent segment degeneration are lacking. In addition, non-industry-sponsored studies indicate that these devices are equivalent to fusion in terms of adjacent segment degeneration. Longer-term studies will eventually provide the definitive answer. PMID:24353955

  15. Total organic carbon analyzer

    NASA Technical Reports Server (NTRS)

    Godec, Richard G.; Kosenka, Paul P.; Smith, Brian D.; Hutte, Richard S.; Webb, Johanna V.; Sauer, Richard L.

    1991-01-01

    The development and testing of a breadboard version of a highly sensitive total-organic-carbon (TOC) analyzer are reported. Attention is given to the system components including the CO2 sensor, oxidation reactor, acidification module, and the sample-inlet system. Research is reported for an experimental reagentless oxidation reactor, and good results are reported for linearity, sensitivity, and selectivity in the CO2 sensor. The TOC analyzer is developed with gravity-independent components and is designed for minimal additions of chemical reagents. The reagentless oxidation reactor is based on electrolysis and UV photolysis and is shown to be potentially useful. The stability of the breadboard instrument is shown to be good on a day-to-day basis, and the analyzer is capable of 5 sample analyses per day for a period of about 80 days. The instrument can provide accurate TOC and TIC measurements over a concentration range of 20 ppb to 50 ppm C.

  16. Primary total elbow arthroplasty

    PubMed Central

    Kumar, Suresh; Mahanta, Sunayan

    2013-01-01

    Background: Primary total elbow arthroplasty (TEA) is a challenging procedure for orthopedic surgeons. It is not performed as frequently as compared to hip or knee arthroplasty. The elbow is a nonweight-bearing joint; however, static loading can create forces up to three times the body weight and dynamic loading up to six times. For elderly patients with deformity and ankylosis of the elbow due to posttraumatic arthritis or rheumatoid arthritis or comminuted fracture distal humerus, arthroplasty is one of the option. The aim of this study is to analyze the role of primary total elbow arthroplasty in cases of crippling deformity of elbow. Materials and Methods: We analyzed 11 cases of TEA, between December 2002 and September 2012. There were 8 females and 3 males. The average age was 40 years (range 30-69 years). The indications for TEA were rheumatoid arthritis, comminuted fracture distal humerus with intraarticular extension, and posttraumatic bony ankylosis of elbow joint. The Baksi sloppy (semi constrained) hinge elbow prosthesis was used. Clinico-radiological followup was done at 1 month, 3 months, 6 months, 1 year, and then yearly basis. Results: In the present study, average supination was 70° (range 60-80°) and average pronation was 70° (range 60-80°). Average flexion was 135° (range 130-135°). However, in 5 cases, there was loss of 15 to 35° (average 25°) of extension (45°) out of 11 cases. The mean Mayo elbow performance score was 95.4 points (range 70-100). Arm length discrepancy was only in four patients which was 36% out of 11 cases. Clinico-radiologically all the elbows were stable except in one case and no immediate postoperative complication was noted. Radiolucency or loosening of ulnar stem was seen in 2 cases (18%) out of 11 cases, in 1 case it was noted after 5 years and in another after 10 years. In second case, revision arthroplasty was done, in which only ulnar hinge section, hinge screw and lock screw with hexagonal head were replaced. Conclusion: Elbow arthroplasty remains a valuable option for deformed and ankylosed elbows especially in the demanding patients with crippling deformity of the elbow. PMID:24379468

  17. The total artificial heart.

    PubMed

    Cook, Jason A; Shah, Keyur B; Quader, Mohammed A; Cooke, Richard H; Kasirajan, Vigneshwar; Rao, Kris K; Smallfield, Melissa C; Tchoukina, Inna; Tang, Daniel G

    2015-12-01

    The total artificial heart (TAH) is a form of mechanical circulatory support in which the patient's native ventricles and valves are explanted and replaced by a pneumatically powered artificial heart. Currently, the TAH is approved for use in end-stage biventricular heart failure as a bridge to heart transplantation. However, with an increasing global burden of cardiovascular disease and congestive heart failure, the number of patients with end-stage heart failure awaiting heart transplantation now far exceeds the number of available hearts. As a result, the use of mechanical circulatory support, including the TAH and left ventricular assist device (LVAD), is growing exponentially. The LVAD is already widely used as destination therapy, and destination therapy for the TAH is under investigation. While most patients requiring mechanical circulatory support are effectively treated with LVADs, there is a subset of patients with concurrent right ventricular failure or major structural barriers to LVAD placement in whom TAH may be more appropriate. The history, indications, surgical implantation, post device management, outcomes, complications, and future direction of the TAH are discussed in this review. PMID:26793338

  18. The total artificial heart

    PubMed Central

    Cook, Jason A.; Shah, Keyur B.; Quader, Mohammed A.; Cooke, Richard H.; Kasirajan, Vigneshwar; Rao, Kris K.; Smallfield, Melissa C.; Tchoukina, Inna

    2015-01-01

    The total artificial heart (TAH) is a form of mechanical circulatory support in which the patient’s native ventricles and valves are explanted and replaced by a pneumatically powered artificial heart. Currently, the TAH is approved for use in end-stage biventricular heart failure as a bridge to heart transplantation. However, with an increasing global burden of cardiovascular disease and congestive heart failure, the number of patients with end-stage heart failure awaiting heart transplantation now far exceeds the number of available hearts. As a result, the use of mechanical circulatory support, including the TAH and left ventricular assist device (LVAD), is growing exponentially. The LVAD is already widely used as destination therapy, and destination therapy for the TAH is under investigation. While most patients requiring mechanical circulatory support are effectively treated with LVADs, there is a subset of patients with concurrent right ventricular failure or major structural barriers to LVAD placement in whom TAH may be more appropriate. The history, indications, surgical implantation, post device management, outcomes, complications, and future direction of the TAH are discussed in this review. PMID:26793338

  19. Unlinked total elbow arthroplasty.

    PubMed

    Marsh, Jonathan P; King, Graham J W

    2015-01-01

    For more than 60 years, total elbow arthroplasty (TEA) has been successfully used to treat a variety of elbow conditions. Although first designed to treat older patients with rheumatoid arthritis, the indications have expanded to include younger, higher-demand patients with a broad range of elbow pathology. Two groups of TEA currently exist. The first group includes linked or semiconstrained elbows with a mechanical connection between the humeral and ulnar components that prevents disassociation. These implants do not rely on muscular or ligamentous tissues for stability. The second group includes unlinked implants that have no physical connection between the humeral and ulnar components. They rely on bearing surface architecture as well as soft-tissue integrity for elbow stability. Critical to the success of unlinked implants is a thorough preoperative evaluation of elbow stability, including bone stock, collateral ligament integrity, and periarticular muscle function. Unlinked implants should apply less strain to the bone-cement-implant interfaces, which may theoretically decrease rates of bearing wear and aseptic loosening. For this reason, some surgeons prefer unlinked implants for younger, higher-demand patients. To date, unlinked implants have not been clinically shown to improve survivorship compared with linked devices. No prospective randomized trials comparing linked and unlinked TEAs are currently available. Historically, unlinked implants have had higher revision rates, mostly caused by instability and early design flaws. More recent series have shown no significant differences in outcomes compared with linked devices. Unlinked TEA provides reliable pain relief and improved range of motion for patients with a variety of elbow disorders. Diligent patient selection and careful surgical technique are of utmost importance when considering an unlinked TEA as a treatment option. The recent development of convertible implants now allows surgeons to make intraoperative decisions regarding elbow stability and convert to a linked implant without revising the stems. PMID:25745909

  20. The clinical and radiological outcomes of hip resurfacing versus total hip arthroplasty: a meta-analysis and systematic review

    PubMed Central

    2010-01-01

    Background and purpose Hip resurfacing (HRS) procedures have gained increasing popularity for younger, higher-demand patients with degenerative hip pathologies. However, with concerns regarding revision rates and possible adverse metal hypersensitivity reactions with metal-on-metal articulations, some authors have questioned the hypothesized superiority of hip resurfacing over total hip arthroplasty (THA). In this meta-analysis, we compared the clinical and radiological outcomes and complication rates of these 2 procedures. Methods A systematic review was undertaken of all published (Medline, CINAHL, AMED, EMBASE) and unpublished or gray literature research databases up to January 2010. Clinical and radiological outcomes as well as complications of HRS were compared to those of THA using risk ratio, mean difference, and standardized mean difference statistics. Studies were critically appraised using the CASP appraisal tool. Results 46 studies were identified from 1,124 citations. These included 3,799 HRSs and 3,282 THAs. On meta-analysis, functional outcomes for subjects following HRS were better than or the same as for subjects with a THA, but there were statistically significantly greater incidences of heterotopic ossification, aseptic loosening, and revision surgery with HRS compared to THA. The evidence base showed a number of methodological inadequacies such as the limited use of power calculations and poor or absent blinding of both patients and assessors, possibly giving rise to assessor bias. Interpretation On the basis of the current evidence base, HRS may have better functional outcomes than THA, but the increased risks of heterotopic ossification, aseptic loosening, and revision surgery following HRS indicate that THA is superior in terms of implant survival. PMID:21067432

  1. Determination of Total Petroleum Hydrocarbons (TPH) Using Total Carbon Analysis

    SciTech Connect

    Ekechukwu, A.A.

    2002-05-10

    Several methods have been proposed to replace the Freon(TM)-extraction method to determine total petroleum hydrocarbon (TPH) content. For reasons of cost, sensitivity, precision, or simplicity, none of the replacement methods are feasible for analysis of radioactive samples at our facility. We have developed a method to measure total petroleum hydrocarbon content in aqueous sample matrixes using total organic carbon (total carbon) determination. The total carbon content (TC1) of the sample is measured using a total organic carbon analyzer. The sample is then contacted with a small volume of non-pokar solvent to extract the total petroleum hydrocarbons. The total carbon content of the resultant aqueous phase of the extracted sample (TC2) is measured. Total petroleum hydrocarbon content is calculated (TPH = TC1-TC2). The resultant data are consistent with results obtained using Freon(TM) extraction followed by infrared absorbance.

  2. Recommended Amounts of Total fruits

    Cancer.gov

    Recommended Amounts of Total fruits Table B1. Total fruits: Estimated percentage of persons below, at, or above recommendation1 Age (years) N Mean (SE) % with intake below recommendation (SE) % with intake meeting recommendation (SE) % with intake above

  3. Recommended Amounts of Total seafood

    Cancer.gov

    Recommended Amounts of Total seafood Table B12. Total seafood: Estimated percentage of persons below, at, or above recommendation1 Age (years) N Mean (SE) % with intake below recommendation (SE) % with intake meeting recommendation (SE) % with intake

  4. Recommended Amounts of Total grains

    Cancer.gov

    Recommended Amounts of Total grains Table B8. Total grains: Estimated percentage of persons below, at, or above recommendation1 Age (years) N Mean (SE) % with intake below recommendation (SE) % with intake meeting recommendation (SE) % with intake above

  5. The Interchangeability of Plasma and Whole Blood Metal Ion Measurement in the Monitoring of Metal on Metal Hips

    PubMed Central

    Malek, Ibrahim A.; Rogers, Joanne; King, Amanda Christina; Clutton, Juliet; Winson, Daniel; John, Alun

    2015-01-01

    One hundred and twenty six paired samples of plasma and whole blood were measured with inductively coupled plasma mass spectrometry technique for metal ions analysis to determine a relationship between them. There was a significant difference between the mean plasma and whole blood concentrations of both cobalt (Co) and chromium (Cr) (p < 0.0001 for both Co and Cr). The mean ratio between plasma and whole blood Cr and Co was 1.56 (range: 0.393.85) and 1.54 (range: 0.6418.26), respectively, but Bland and Altman analysis illustrated that this relationship was not universal throughout the range of concentrations. There was higher variability at high concentrations for both ions. We conclude that both these concentrations should not be used interchangeably and conversion factors are unreliable due to concentration dependent variability. PMID:26798516

  6. Total Quality and Organization Development. Total Quality Series.

    ERIC Educational Resources Information Center

    Lindsay, William M.; Petrick, Joseph A.

    As the global business environment becomes more turbulent, quality management seems more indispensable. This book offers strategies for integrating the theory and practice of Total Quality Management (TQM) with organizational-development (OD) theory at all organizational levels. Chapter 1 answers the question "Why Total Quality Management and

  7. Total Quality and Organization Development. Total Quality Series.

    ERIC Educational Resources Information Center

    Lindsay, William M.; Petrick, Joseph A.

    As the global business environment becomes more turbulent, quality management seems more indispensable. This book offers strategies for integrating the theory and practice of Total Quality Management (TQM) with organizational-development (OD) theory at all organizational levels. Chapter 1 answers the question "Why Total Quality Management and…

  8. Total synthesis of bryostatin 9.

    PubMed

    Wender, Paul A; Schrier, Adam J

    2011-06-22

    The total synthesis of bryostatin 9 was accomplished using a uniquely step-economical and convergent Prins-driven macrocyclization strategy. At 25 linear and 42 total steps, this is currently the most concise and convergent synthesis of a potent bryostatin. PMID:21618969

  9. Total Synthesis of Bryostatin 9

    PubMed Central

    Wender, Paul A.; Schrier, Adam J.

    2011-01-01

    The total synthesis of bryostatin 9 was accomplished using a uniquely step economical and convergent Prins-driven macrocyclization strategy. At 25 linear and 42 total steps, this is currently the most concise and convergent (5 steps post fragment coupling) synthesis of a potent bryostatin. PMID:21618969

  10. The total charm cross section

    SciTech Connect

    Vogt, R

    2007-09-14

    We assess the theoretical uncertainties on the total charm cross section. We discuss the importance of the quark mass, the scale choice and the parton densities on the estimate of the uncertainty. We conclude that the uncertainty on the total charm cross section is difficult to quantify.

  11. Infection prevention in total knee and total hip arthroplasties.

    PubMed

    Kuper, Mark; Rosenstein, Alexander

    2008-01-01

    Infection after primary joint arthroplasty is responsible for severe morbidity to the patients and staggering costs to society. Understanding the patient population undergoing these procedures and the use of appropriate prophylactic regiments and precautions in the perioperative and postoperative periods is crucial for the ultimate success of the procedures. In this article, we review the current related literature and our techniques for reducing the likelihood of infection after total knee and total hip arthroplasties. PMID:18309390

  12. Minimally invasive total hip arthroplasty.

    PubMed

    Hohler, Sharon E

    2004-06-01

    Total hip arthroplasty procedures relieve patients' arthritic hip pain. Since the first procedure was performed in the 1960s, surgeons and implant companies have worked to improve prosthesis design, composition of implants, and the mechanisms for holding the implants in place. Recently, surgeons have focused on minimizing the surgical incision. Smaller incisions have resulted in smaller scars and faster recoveries. This article presents a brief historical overview of, as well as current trends in, minimally invasive total hip arthroplasty. All aspects of care for a patient undergoing total hip arthroplasty are discussed. PMID:15239326

  13. A Choir for Total Communication.

    ERIC Educational Resources Information Center

    Knapp, Ruth Ann

    1980-01-01

    The Total Communication Choir of the Saginaw, Michigan, public schools integrates deaf and hearing elementary and junior high students in music performance. All students both sign and sing. Methods used to instruct the choir are described. (SJL)

  14. Pyodermatitis vegetans after total colectomy.

    PubMed

    Uzunçakmak, Tuğba Kevser; Akdeniz, Necmettin; Karadağ, Ayşe Serap; Çobanoğlu, Bengü

    2015-12-01

    Pyostomatitis-pyodermatitis vegetans (PPV) is a rare dermatological manifestation of inflammatory bowel disease, characterized by erythematous, vesiculopustular, exudative, annular, and/or vegetating plaques over the intertriginous regions that may precede or appear at the same time as the mucosal lesions. Systemic corticosteroids, dapsone, sulfasalazine, azathioprine, cyclosporine, and subtotal/total colectomy are the most common treatment options. A 16-year-old male patient presented to our outpatient clinic with a four months history of thickly crusted erosions on his trunk, back, and lower extremity. He had ulcerative colitis for four years and total colectomy was done seven months ago. Clinical and histopathological examination of his lesions were consistent with pyostomatitis vegetans. Although subtotal/total colectomy has been reported as a treatment option for PPV, lesions reappeared three months after total colectomy in our patient. PMID:26904460

  15. Pyodermatitis vegetans after total colectomy

    PubMed Central

    Uzunçakmak, Tuğba Kevser; Akdeniz, Necmettin; Karadağ, Ayşe Serap; Çobanoğlu, Bengü

    2015-01-01

    Pyostomatitis–pyodermatitis vegetans (PPV) is a rare dermatological manifestation of inflammatory bowel disease, characterized by erythematous, vesiculopustular, exudative, annular, and/or vegetating plaques over the intertriginous regions that may precede or appear at the same time as the mucosal lesions. Systemic corticosteroids, dapsone, sulfasalazine, azathioprine, cyclosporine, and subtotal/total colectomy are the most common treatment options. A 16-year-old male patient presented to our outpatient clinic with a four months history of thickly crusted erosions on his trunk, back, and lower extremity. He had ulcerative colitis for four years and total colectomy was done seven months ago. Clinical and histopathological examination of his lesions were consistent with pyostomatitis vegetans. Although subtotal/total colectomy has been reported as a treatment option for PPV, lesions reappeared three months after total colectomy in our patient. PMID:26904460

  16. Toward total quality in industry

    NASA Astrophysics Data System (ADS)

    Andre, Pierre

    A total quality management methodology is described, and then illustrated by examples from the aircraft industry. In particular, the application of this methodology to SNECMA engines has been shown to be effective.

  17. Total Synthesis of Epicoccin G

    PubMed Central

    Nicolaou, K. C.; Totokotsopoulos, Sotirios; Giguère, Denis; Sun, Ya-Ping; Sarlah, David

    2011-01-01

    An expedient enantioselective total synthesis of epicoccin G and related dithiodiketopiperazines through a strategy featuring direct two-directional sulfenylation, photooxygenation and Kornblum–DeLaMare rearrangement is described. PMID:21548595

  18. Total arsenic in rice milk.

    PubMed

    Shannon, Ron; Rodriguez, Jose M

    2014-01-01

    Rice milk and its by-products were tested for total arsenic concentration. Total arsenic concentration was determined using graphite-furnace atomic absorption spectrometry. The arsenic concentrations ranged from 2.7 0.3 to 17.9 0.5 g L(-1). Rice milk and its by-products are not clearly defined as food, water or milk substitute. The US Environmental Protection Agency (EPA), the European Union (EU) and the World Health Organization (WHO) have set a level of 10 g L(-1) for total arsenic concentrations in drinking water. The EU and the US regulatory agencies do not provide any guidelines on total arsenic concentrations in foods. This study provides us with a starting point to address this issue in the State of Mississippi, USA. PMID:24779982

  19. Stereoselective Total Synthesis of (-)-Depudecin.

    PubMed

    García-Ruiz, Cristina; Cheng-Sánchez, Iván; Sarabia, Francisco

    2015-11-20

    The total synthesis of the natural product depudecin, an antiangiogenic microbial polyketide with inhibitory activity against histone deacetylases, is reported. Characterized by a highly oxidized 11-carbon chain containing two epoxides conjugated through a trans-disubstituted olefin, its total synthesis was efficiently accomplished by a novel asymmetric methodology of epoxide formation based on a new class of chiral sulfonium salts, allowing for the construction of the oxirane rings in an efficient and stereoselective fashion. PMID:26517569

  20. Corrosion at the Head-Neck Taper as a Cause for Adverse Local Tissue Reactions After Total Hip Arthroplasty

    PubMed Central

    John Cooper, H.; Della Valle, Craig J.; Berger, Richard A.; Tetreault, Matthew; Paprosky, Wayne G.; Sporer, Scott M.; Jacobs, Joshua J.

    2012-01-01

    Background: Corrosion at the modular head-neck junction of the femoral component in total hip arthroplasty has been identified as a potential concern, although symptomatic adverse local tissue reactions secondary to corrosion have rarely been described. Methods: We retrospectively reviewed the records of ten patients with a metal-on-polyethylene total hip prosthesis, from three different manufacturers, who underwent revision surgery for corrosion at the modular head-neck junction. Results: All patients presented with pain or swelling around the hip, and two patients presented with recurrent instability. Serum cobalt levels were elevated prior to the revision arthroplasty and were typically more elevated than were serum chromium levels. Surgical findings included large soft-tissue masses and surrounding tissue damage with visible corrosion at the femoral head-neck junction; the two patients who presented with instability had severe damage to the hip abductor musculature. Pathology specimens consistently demonstrated areas of tissue necrosis. The patients were treated with debridement and a femoral head and liner exchange, with use of a ceramic femoral head with a titanium sleeve in eight cases. The mean Harris hip score improved from 58.1 points preoperatively to 89.7 points at a mean of 13.0 months after the revision surgery (p = 0.01). Repeat serum cobalt levels, measured in six patients at a mean of 8.0 months following revision, decreased to a mean of 1.61 ng/mL, and chromium levels were similar to prerevision levels. One patient with moderate hip abductor muscle necrosis developed recurrent instability after revision and required a second revision arthroplasty. Conclusions: Adverse local tissue reactions can occur in patients with a metal-on-polyethylene bearing secondary to corrosion at the modular femoral head-neck taper, and their presentation is similar to the adverse local tissue reactions seen in patients with a metal-on-metal bearing. Elevated serum metal levels, particularly a differential elevation of serum cobalt levels with respect to chromium levels, can be helpful in establishing this diagnosis. Level of Evidence: Diagnostic Level III. See Instructions for Authors for a complete description of levels of evidence. PMID:23289127

  1. Total Quality Management Is Total at Fox Valley Technical College.

    ERIC Educational Resources Information Center

    Tyler, Carol R.

    1993-01-01

    At Fox Valley Technical College (Wisconsin), application of Total Quality Management (TQM) brought positive outcomes and other effects. Areas in which TQM was used are considered, including admissions, employee safety, customer focus, policy formation, management performance appraisal, student services, creation of a self-managing class, TQM for

  2. Total body water and total body potassium in anorexia nervosa

    SciTech Connect

    Dempsey, D.T.; Crosby, L.O.; Lusk, E.; Oberlander, J.L.; Pertschuk, M.J.; Mullen, J.L.

    1984-08-01

    In the ill hospitalized patient with clinically relevant malnutrition, there is a measurable decrease in the ratio of the total body potassium to total body water (TBK/TBW) and a detectable increase in the ratio of total exchangeable sodium to total exchangeable potassium (Nae/Ke). To evaluate body composition analyses in anorexia nervosa patients with chronic uncomplicated semistarvation, TBK and TBW were measured by whole body K40 counting and deuterium oxide dilution in 10 females with stable anorexia nervosa and 10 age-matched female controls. The ratio of TBK/TBW was significantly (p less than 0.05) higher in anorexia nervosa patients than controls. The close inverse correlation found in published studies between TBK/TBW and Nae/Ke together with our results suggest that in anorexia nervosa, Nae/Ke may be low or normal. A decreased TBK/TBW is not a good indicator of malnutrition in the anorexia nervosa patient. The use of a decreased TBK/TBW ratio or an elevated Nae/Ke ratio as a definition of malnutrition may result in inappropriate nutritional management in the patient with severe nonstressed chronic semistarvation.

  3. Total Irradiance Monitor Observations of Total Solar Irradiance

    NASA Astrophysics Data System (ADS)

    Kopp, G.

    2007-12-01

    The Total Irradiance Monitor (TIM) is the most recent instrument launched to measure total solar irradiance (TSI) from space. This electrical substitution radiometer has on-orbit degradation tracking to provide very stable long- term measurements of the net solar radiation incident on the Earth, and the instrument continues the 29-year record of this natural driver of Earth climate. Currently flying on the SOlar Radiation and Climate Experiment (SORCE), the TIM has been providing stable, low-noise, and accurate measurements of TSI since early 2003. The TIM will next be flying on NASA's Glory climate mission and is one instrument of the Total Solar Irradiance Sensor (TSIS) selected to continue this important climate record well into the future. The SORCE/TIM has created renewed interest in the TSI absolute value and has acquired the first measurements of the total radiant energy released by large solar flares. Improvements in ground-based calibrations starting with the Glory/TIM will establish traceability linking current to upcoming measurements, solidifying the existing TSI climate data record in the undesirable event of a future data gap.

  4. Total internal inflection fluorescent microscopy.

    PubMed

    Axelrod, D; Thompson, N L; Burghardt, T P

    1983-01-01

    This review discusses applications of fluorescence microscopy using totally internally reflected excitation light. When totally internally reflected in a transparent solid at its interface liquid, the excitation light beam penetrates only a short distance into the liquid. This surface electromagnetic field, called the 'evanescent wave', can selectively excite fluorescent molecules in the liquid near the interface. Total internal reflection fluorescence (TIRF) has been used to examine the cell/substrate contact regions of primary cultured rat myotubes with acetylcholine receptors labelled by fluorescent alpha-bungarotoxin and human skin fibroblasts labelled with a membrane-incorporated fluorescent lipid. TIRF examination of cell/surface contacts dramatically reduces background from cell autofluorescence and debris. TIRF has also been combined with fluorescence photobleaching recovery and correlation spectroscopy to measure the chemical kinetic binding rates and surface diffusion constant of fluorescent labelled serum protein binding (at equilibrium) to a surface. PMID:6827590

  5. Totally Ossified Metaplastic Spinal Meningioma

    PubMed Central

    Hida, Kazutoshi; Yamauchi, Tomohiro; Houkin, Kiyohiro

    2013-01-01

    A 61-year-old woman with a very rare case of totally ossified large thoracic spinal metaplastic meningioma, showing progressing myelopathy is presented. Computed tomographic images showed a large totally ossfied intradural round mass occupying the spinal canal on T9-10 level. Magnetic resonance imaging revealed a large T9-10 intradural extramedullary mass that was hypointense to spinal cord on T1- and T2-weighted sequences, partial enhancement was apparent after Gadolinium administration. The spinal cord was severely compressed and displaced toward the right at the level of T9-10. Surgical removal of the tumor was successfully accomplished via the posterior midline approach and the histological diagnosis verified an ossified metaplastic meningioma. The clinical neurological symptoms of patient were improved postoperatively. In this article we discuss the surgical and pathological aspects of rare case of spinal totally ossified metaplastic meningioma. PMID:24278660

  6. Total eclipses of the sun.

    PubMed

    Zirker, J B

    1980-12-19

    Total eclipses of the sun offer research opportunities in a variety of sciences. Some of the advances in solar physics resulting from eclipse observations are discussed. Experiments at the total eclipse of 16 February 1980 in India are also described. These included a test of general relativity, studies in coronal physics, investigations of solar prominences, diameter measurements, a search for interplanetary dust, a study of the gravity waves in the earth's atmosphere, and experiments on the biological effects on animals and humans. PMID:17817829

  7. Advances in total scattering analysis

    SciTech Connect

    Proffen, Thomas E; Kim, Hyunjeong

    2008-01-01

    In recent years the analysis of the total scattering pattern has become an invaluable tool to study disordered crystalline and nanocrystalline materials. Traditional crystallographic structure determination is based on Bragg intensities and yields the long range average atomic structure. By including diffuse scattering into the analysis, the local and medium range atomic structure can be unravelled. Here we give an overview of recent experimental advances, using X-rays as well as neutron scattering as well as current trends in modelling of total scattering data.

  8. Total Quality Management for Schools.

    ERIC Educational Resources Information Center

    Greenwood, Malcolm S.; Gaunt, Helen J.

    Education in the United Kingdom has been shaped by the advent of local school management and the rapid growth of grant-maintained schools. Total Quality Management (TQM) offers a new way of looking at management principles and structures by identifying the needs of both internal and external customers. This book applies principles of TQM

  9. Total Quality Management for Schools.

    ERIC Educational Resources Information Center

    Greenwood, Malcolm S.; Gaunt, Helen J.

    Education in the United Kingdom has been shaped by the advent of local school management and the rapid growth of grant-maintained schools. Total Quality Management (TQM) offers a new way of looking at management principles and structures by identifying the needs of both internal and external customers. This book applies principles of TQM…

  10. Total Knee Replacement for Women

    MedlinePLUS

    Zimmer Combines Gender Solutions technology May 27, 2009 Good evening. Welcome to “OR-Live” at Tampa General Hospital. My name is ... Florida. Tonight I’ll be moderating a Zimmer Gender Solutions total knee, performed by my partner, Dr. ...

  11. Total Synthesis of Sporolide B**

    PubMed Central

    Nicolaou, K. C.; Tang, Yefeng; Wang, Jianhua

    2009-01-01

    The first total synthesis of the highly oxygenated, marine derived, natural product sporolide B was achieved through a convergent strategy involving a ruthenium-catalyzed [2+2+2] cycloaddition to assemble the indene structural motif and a thermally-induced Diels-Alder-type reaction to forge the macrocycle. PMID:19241430

  12. Infection Following Total Knee Arthroplasty

    PubMed Central

    Chun, Keun Churl; Kim, Kwang Mee

    2013-01-01

    For most orthopedists, total knee arthroplasty (TKA) has been regarded as the most effective surgery for patients with severe knee diseases. Though seldom occur, postoperative infection certainly remains one of the most devastating and dreaded complications of TKA. Thus, careful and early diagnosis is needed. After diagnosis, categorize the infection type and choose a rightful and sequential step of treatment are recommended. PMID:24032096

  13. Total synthesis of cribrostatin 6.

    PubMed

    Knueppel, Daniel; Martin, Stephen F

    2009-01-01

    Fast and furious: Cribrostatin 6, an antimicrobial and antineoplastic agent, was the target of a total synthesis where the longest linear sequence was only four steps. The key step involves a tandem 4pi electrocyclic ring opening, radical cyclization, and homolytic aromatic substitution sequence to afford the tricyclic core of the natural product. PMID:19235818

  14. Total synthesis of (-)-bitungolide F.

    PubMed

    Su, Yingpeng; Xu, Yanfen; Han, Junjie; Zheng, Jiyue; Qi, Jing; Jiang, Tuo; Pan, Xinfu; She, Xuegong

    2009-04-01

    An efficient total synthesis of (-)-bitungolide F (6) in 17 steps and 20.1% yield is described herein. Key steps involve a Myers asymmetric alkylation to introduce the C6 methyl with proper stereochemistry, a Claisen-like cyclization to construct the alpha,beta-unsaturated delta-lactone and a Julia-Kocienski olefination to assemble the conjugated diene moiety. PMID:19323573

  15. Total synthesis of spirobacillene A.

    PubMed

    Unsworth, William P; Cuthbertson, James D; Taylor, Richard J K

    2013-07-01

    The first total synthesis of spirobacillene A, an indole alkaloid isolated from Lysinibacillus fusiformis, is reported. A Lewis acid mediated spirocyclization of an anisole derivative onto a tethered ynone was used as a key step, drawing inspiration from a potential biosynthesis of the natural product. PMID:23786419

  16. The first Polish total laryngectomies.

    PubMed

    Kierzek, Andrzej; Paprocka-Borowicz, Ma?gorzata; Pozowski, Andrzej; Kuciel-Lewandowska, Jadwiga

    2013-01-01

    The total removal of the larynx (total laryngectomy), performed in 1872 by the well-known Viennese surgeon Christian A. Theodor Billroth (1829-1894), was an epoch-making event in the history of surgery and laryngology. This paper presents the first surgeons who performed this operation. The first Pole who performed a total laryngectomy (1877) was Julian Kosi?ski (1833-1914), head of the Surgical Clinic of Imperial University Warsaw. It was the 14(th) operation of this kind in the world. Several laryngectomies were carried out by Franciszek Ksawery Jawdy?ski (1851-1896), called the father of Polish head and neck surgery, who was the first Pole to excise a malignant neck cancer together with the lymph nodes. The next total laryngectomies were performed by the following Polish surgeons: Jan Mikulicz-Radecki (1850-1905), W?adys?aw H.S. Krajewski (1855-1907), Alfred Obali?ski (1843-1898). According to Jan S?dziak, by 1897 Poland with 16 laryngectomies (per 188 carried out) had occupied the fourth position in the world. The failures of the first laryngectomies were due to such factors as the ignorance of shock pathophysiology, the inability to ensure the patency of the airways during and after the operation, which would result in lung and mediastinum infections, massive haemorrhages and so on. But the primary cause was the lack of constructive collaboration between the laryngologists and the surgeons. PMID:24592132

  17. Total Synthesis of (-)-Enigmazole A.

    PubMed

    Ai, Yanran; Kozytska, Mariya V; Zou, Yike; Khartulyari, Anton S; Smith, Amos B

    2015-12-16

    A highly convergent, stereocontrolled total synthesis of the architecturally complex marine sponge metabolite (-)-enigmazole A has been achieved. Highlights include an unprecedented late-stage large-fragment Petasis-Ferrier union/rearrangement, a multicomponent Type I Anion Relay Chemistry (ARC) tactic, and a dithiane-epoxide union in conjunction with an oxazole-directed stereoselective reduction. PMID:26632969

  18. Total Synthesis of Propolisbenzofuran B†

    PubMed Central

    Jones, Brian T.; Avetta, Christopher T.; Thomson, Regan J.

    2014-01-01

    The first total synthesis of propolisbenzofuran B, a bioactive natural product isolated from honeybee propolis resin, is reported. The convergent synthesis makes use of a silicon-tether controlled oxidative ketone–ketone cross-coupling and a novel benzofuran-generating cascade reaction to deliver the core structure of the natural product from readily prepared precursors. PMID:24976944

  19. The first Polish total laryngectomies

    PubMed Central

    Paprocka-Borowicz, Ma?gorzata; Pozowski, Andrzej; Kuciel-Lewandowska, Jadwiga

    2013-01-01

    The total removal of the larynx (total laryngectomy), performed in 1872 by the well-known Viennese surgeon Christian A. Theodor Billroth (18291894), was an epoch-making event in the history of surgery and laryngology. This paper presents the first surgeons who performed this operation. The first Pole who performed a total laryngectomy (1877) was Julian Kosi?ski (18331914), head of the Surgical Clinic of Imperial University Warsaw. It was the 14th operation of this kind in the world. Several laryngectomies were carried out by Franciszek Ksawery Jawdy?ski (18511896), called the father of Polish head and neck surgery, who was the first Pole to excise a malignant neck cancer together with the lymph nodes. The next total laryngectomies were performed by the following Polish surgeons: Jan Mikulicz-Radecki (18501905), W?adys?aw H.S. Krajewski (18551907), Alfred Obali?ski (18431898). According to Jan S?dziak, by 1897 Poland with 16 laryngectomies (per 188 carried out) had occupied the fourth position in the world. The failures of the first laryngectomies were due to such factors as the ignorance of shock pathophysiology, the inability to ensure the patency of the airways during and after the operation, which would result in lung and mediastinum infections, massive haemorrhages and so on. But the primary cause was the lack of constructive collaboration between the laryngologists and the surgeons. PMID:24592132

  20. Enantioselective total synthesis of (+)-amabiline.

    PubMed

    Senter, Timothy J; Fadeyi, Olugbeminiyi O; Lindsley, Craig W

    2012-04-01

    The first total synthesis of (+)-amabiline, an unsaturated pyrrolizidine alkaloid from Cynoglossum amabile, is reported. This convergent, enantioselective synthesis proceeds in 15 steps (10-step longest linear sequence) in 6.2% overall yield and features novel methodology to construct the unsaturated pyrrolizidine or (-)-supinidine core. PMID:22432912

  1. Thyroidectomy in Graves' disease: subtotal, near total or total?

    PubMed

    Hoffmann, Rainer

    2009-01-01

    Thyroidectomy is one of the possible therapeutic options in Graves' disease as are antithyroid drugs and (131)radioiodine. Emerging data reveal an advantage of total thyroidal ablation as the method of choice in patients with impending or overt Graves' orbitopathy. Pros and cons are discussed as presented at the 1st Swiss Symposium on Thyroid Eye Disease in Pontresina, Switzerland in December 2007. PMID:19839882

  2. Implant based differences in adverse local tissue reaction in failed total hip arthroplasties: a morphological and immunohistochemical study

    PubMed Central

    2014-01-01

    Background Adverse local tissue reaction (ALTR) is characterized by periprosthetic soft tissue inflammation composed of a mixed inflammatory cell infiltrate, extensive soft tissue necrosis, and vascular changes. Multiple hip implant classes have been reported to result in ALTR, and clinical differences may represent variation in the soft tissue response at the cellular and tissue levels. The purpose of this study was to describe similarities and differences in periprosthetic tissue structure, organization, and cellular composition by conventional histology and immunohistochemistry in ALTR resulting from two common total hip arthroplasty (THA) implant classes. Methods Consecutive patients presenting with ALTR from two major hip implant classes (N = 54 patients with Dual-Modular Neck implant; N = 14 patients with Metal-on-Metal implant) were identified from our prospective Osteolysis Tissue Database and Repository. Clinical characteristics including age, sex, BMI, length of implantation, and serum metal ion levels were recorded. Retrieved synovial tissue morphology was graded using light microscopy and cellular composition was assessed using immunohistochemistry. Results Length of implantation was shorter in the DMN group versus MoM THA group (21.3 [8.4] months versus 43.6 [13.8] months respectively; p < 0.005) suggesting differences in implant performance. Morphologic examination revealed a common spectrum of neo-synovial proliferation and necrosis in both groups. Macrophages were more commonly present in diffuse sheets (Grade 3) in the MoM relative to DMN group (p = 0.016). Perivascular lymphocytes with germinal centers (Grade 4) were more common in the DMN group, which trended towards significance (p = 0.066). Qualitative differences in corrosion product morphology were seen between the two groups. Immunohistochemistry showed features of a CD4 and GATA-3 rich lymphocyte reaction in both implants, with increased ratios of perivascular T-cell relative to B-cell markers in the DMN relative to the MoM group (p = 0.032). Conclusion Our results demonstrate that both implant classes display common features of neo-synovial proliferation and necrosis with a CD4 and GATA-3 rich inflammatory infiltrate. Qualitative differences in corrosion product appearance, macrophage morphology, and lymphocyte distributions were seen between the two implant types. Our data suggests that ALTR represents a histological spectrum with implant-based features. PMID:25242891

  3. Solar total energy project Shenandoah

    NASA Astrophysics Data System (ADS)

    1980-01-01

    A description of the final design for the Solar Total Energy System to be installed at the Shenandoah, Georgia, site of utilization by the Bleyle knitwear plant, is presented. The system is a fully cascaded total energy system design featuring high temperature paraboloidal dish solar collectors with a 235 concentration ratio, a steam Rankine cycle power conversion system capable of supplying 100 to 400 kW(e) output with an intermediate process steam take-off point, and a back pressure condenser for heating and cooling. The design also includes an integrated control system employing the supervisory control concept to allow maximum experimental flexibility. The system design criteria and requirements are presented including the performance criteria and operating requirements, environmental conditions of operation; interface requirements with the Bleyle plant and the Georgia Power Company lines; maintenance, reliability, and testing requirements; health and safety requirements; and other applicable ordinances and codes.

  4. A simple total energy sensor

    NASA Technical Reports Server (NTRS)

    Nicks, O. W.

    1976-01-01

    This research concerns a simple technique for total energy compensation having the primary requirement of good compensation with a low cost, easy to make sensor. A comprehensive library search and a small wind tunnel were used to explore fundamentals and to develop a number of probes which were flight tested with satisfactory results. Simple probe configurations were tested using the characteristics of laminar flow separation around a small cylinder to produce a sensor pressure having the desired relationship between static and dynamic pressures. Wind tunnel and flight tests confirmed the concepts for a wide range of speeds, altitudes, and flow directions encountered in soaring. Data and findings are presented, along with a discussion of factors important to total energy compensation.

  5. Instability After Total Knee Arthroplasty.

    PubMed

    Cottino, Umberto; Sculco, Peter K; Sierra, Rafael J; Abdel, Matthew P

    2016-04-01

    Instability is one of the most common causes of failure after total knee arthroplasty. Although there are several contributing causes, surgical error and poor implant design selection contribute. For this reason, an accurate diagnosis is fundamental and is largely based on a thorough history and physical examination. In general, tibiofemoral instability can be classified into 3 different patterns: flexion instability, genu recurvatum, and extension instability. In this article, these 3 patterns are reviewed in greater depth. PMID:26772939

  6. Total Synthesis of (+)-Rubriflordilactone A

    PubMed Central

    Goh, Shermin S; Chaubet, Guilhem; Gockel, Birgit; Cordonnier, Marie-Caroline A; Baars, Hannah; Phillips, Andrew W; Anderson, Edward A

    2015-01-01

    Two enantioselective total syntheses of the nortriterpenoid natural product rubriflordilactone A are described, which use palladium- or cobalt-catalyzed cyclizations to form the CDE rings, and converge on a late-stage synthetic intermediate. These key processes are set up through the convergent coupling of a common diyne component with appropriate AB-ring aldehydes, a strategy that sets the stage for the synthetic exploration of other members of this family of natural products. PMID:26337920

  7. The infected total hip arthroplasty.

    PubMed

    Salvati, Eduardo A; Gonzlez Della Valle, Alejandro; Masri, Bassam A; Duncan, Clive P

    2003-01-01

    Deep infection following total hip arthroplasty remains one of the most serious local complications preventing a successful outcome. Correct diagnosis of infection is dependent on identification of the pathogen. Treatment consists of incision and debridement. Before surgery, the patient should be in good dental health, have good nutritional status, and should be free of infection in any organ system that can later seed the artificial joint. PMID:12690851

  8. Asymmetric total synthesis of rollicosin.

    PubMed

    Quinn, Kevin J; Isaacs, Andr K; DeChristopher, Brian A; Szklarz, Stephanie C; Arvary, Rebecca A

    2005-03-31

    [structure: see text] The first total synthesis of rollicosin, a member of a rare subgroup of Annonaceous acetogenins containing two terminal gamma-lactones, is reported. The approach features a highly regio- and stereoselective tandem ring-closing/cross-metathesis reaction for construction of the east-wing lactone and incorporation of the alkyl spacer. Establishment of the C4 stereocenter and addition of the west-wing lactone were achieved by Sharpless asymmetric dihydroxylation and enolate alkylation. PMID:15787477

  9. Asymmetric total synthesis of neoxaline.

    PubMed

    Ideguchi, Tetsuya; Yamada, Takeshi; Shirahata, Tatsuya; Hirose, Tomoyasu; Sugawara, Akihiro; Kobayashi, Yoshinori; ?mura, Satoshi; Sunazuka, Toshiaki

    2013-08-28

    A first asymmetric total synthesis and determination of the absolute configuration of neoxaline has been accomplished through the highly stereoselective introduction of a reverse prenyl group to create a quaternary carbon stereocenter using (-)-3a-hydroxyfuroindoline as a building block, construction of the indoline spiroaminal via cautious stepwise oxidations with cyclizations from the indoline, assembly of (Z)-dehydrohistidine, and photoisomerization of unnatural (Z)-neoxaline to the natural (E)-neoxaline as the key steps. PMID:23957424

  10. Total Synthesis of ()-Actinophyllic Acid

    PubMed Central

    2008-01-01

    The first total synthesis of ()-actinophyllic acid (1) is reported. Key steps of this synthesis include an intramolecular oxidative coupling of ketone and malonic ester enolates and an aza-Cope?Mannich rearrangement that assembled the core structure of the natural products unique ring system. The synthesis was accomplished from di-tert-butyl malonate in 8% overall yield by a concise sequence that proceeds by way of only seven isolated intermediates. PMID:18491907

  11. Total Synthesis of Aplyronine C

    PubMed Central

    2013-01-01

    A highly stereocontrolled total synthesis of the cytotoxic marine macrolide aplyronine C is described. The route exploits aldol methodology to install the requisite stereochemistry and features a crucial boron-mediated aldol coupling of an N-vinylformamide-bearing methyl ketone with a macrocyclic aldehyde to introduce the full side chain. The synthesis of two novel C21C34 side chain analogs is also reported. PMID:23730909

  12. Enantioselective Total Synthesis of Aplyviolene

    PubMed Central

    Overman, Larry E.; Schnermann, Martin J.

    2011-01-01

    The enantioselective total synthesis of the rearranged spongian diterpene aplyviolene has been completed in 14 steps from the known hydroazulenone 8. The key junction of the hydrocarbon and oxygenated fragments to form the critical C8 quaternary carbon stereocenter and set the stage for elaborating the delicate bicyclic lactone functionality was accomplished in high yield and exquisite stereoselectivity by Michael addition of an enantioenriched hydroazulenone enolate to an enantiopure α-bromocyclopentenone. PMID:21936525

  13. Advances in total knee arthroplasty.

    PubMed

    Aumiller, Wade D; Dollahite, Harry Anderson

    2016-03-01

    Total knee arthroplasty (TKA) is one of the success stories of modern surgery. Primary TKA is commonly used when nonsurgical treatments for osteoarthritis fail. The need for TKA is projected to increase by 673% between 2005 and 2030, creating a tremendous burden on the healthcare system. This article reviews selected perioperative management strategies, computer-aided navigation, patient-specific cutting blocks, and medial pivot knee implants as potential sources of improvements in clinical efficiency and patient outcomes. PMID:26840607

  14. Total Pancreatectomy With Islet Autotransplantation

    PubMed Central

    Bellin, Melena D.; Gelrud, Andres; Arreaza-Rubin, Guillermo; Dunn, Ty B.; Humar, Abhinav; Morgan, Katherine A.; Naziruddin, Bashoo; Rastellini, Cristiana; Rickels, Michael R.; Schwarzenberg, Sarah J.; Andersen, Dana K.

    2015-01-01

    A workshop sponsored by the National Institute of Diabetes and Digestive and Kidney Diseases focused on research gaps and opportunities in total pancreatectomy with islet autotransplantation (TPIAT) for the management of chronic pancreatitis. The session was held on July 23, 2014 and structured into 5 sessions: (1) patient selection, indications, and timing; (2) technical aspects of TPIAT; (3) improving success of islet autotransplantation; (4) improving outcomes after total pancreatectomy; and (5) registry considerations for TPIAT. The current state of knowledge was reviewed; knowledge gaps and research needs were specifically highlighted. Common themes included the need to identify which patients best benefit from and when to intervene with TPIAT, current limitations of the surgical procedure, diabetes remission and the potential for improvement, opportunities to better address pain remission, GI complications in this population, and unique features of children with chronic pancreatitis considered for TPIAT. The need for a multicenter patient registry that specifically addresses the complexities of chronic pancreatitis and total pancreatectomy outcomes and postsurgical diabetes outcomes was repeatedly emphasized. PMID:25599324

  15. CLINICAL OUTCOME AFTER INFECTED TOTAL KNEE AND TOTAL HIP ARTHROPLASTY

    PubMed Central

    Mittag, Falk; Leichtle, Carmen Ina; Schlumberger, Michael; Leichtle, Ulf Gunther; Wünschel, Markus

    2016-01-01

    ABSTRACT Objective: Infection after total hip (THA) and knee arthroplasty (TKA) is a serious complication which typically leads to a long lasting and intensive surgical and medicamentous treatment. The aim of this study was to identify factors that influence outcome after revision surgery caused by prosthetic infection. Methods: We retrospectively analyzed 64 patients who had revision surgery between 1989 and 2009 due to periprosthetic infection. We examined a total of 69 joints (TKA: 36%, THA: 64%), follow-up 5.1 years (0.5-21 years) after the initial surgical intervention. The mean patient age at time of surgery was 67 years old (43-79 years old). Clinical data and scores including the Western Ontario and McMaster Universities (WOMAC)-Index, the Harris Hip Score (HHS) and the Hospital for Special Surgery Score (HSS) were surveyed. Results: There was no difference in clinical scores regarding treatment between a single and a multiple stage treatment regime. Infections with multiple microorganisms and Enterococcus spp. lead to a significantly higher number of interventions. Using a modified Tsukayama system we classified 24% as type I, 34% type II and 42% type III- infections, with no differences in clinical outcome. Overweight patients had a significantly lower HHS and WOMAC-score. Immunosuppression leads to a worse WOMAC and HSS-Score. An increased number of procedures was associated to a limping gait. Conclusion: Thorough surgical technique leads to good clinical results independent of infection-type and treatment philosophy. Level of Evidence III, Case Control Study.

  16. Is there any difference in survivorship of total hip arthroplasty with different bearing surfaces? A systematic review and network meta-analysis

    PubMed Central

    Yin, Si; Zhang, Dangfeng; Du, Hui; Du, Heng; Yin, Zhanhai; Qiu, Yusheng

    2015-01-01

    Purpose: Although many total hip bearing implants are widely used all over the world, simultaneous comparisons across the numerous available bearing surfaces are rare. The purpose of this study was to compare the survivorship of total hip arthroplasty (THA) with six available bearing implants. Methods: We conducted a systematic review of randomized controlled trials (RCTs) reporting survivorship or revision of ceramic-on-ceramic (CoC), ceramic-on-conventional polyethylene (CoPc), ceramic-on-highly-crosslinked polyethylene (CoPxl), metal-on-conventional polyethylene (MoPc), metal-on-highly-crosslinked polyethylene (MoPxl), or metal-on-metal (MoM) bearing implants. The synthesis of present evidence was performed by both the traditional direct-comparison meta-analysis and network meta-analysis. Results: In total, 40 RCTs involving a total of 5321 THAs were identified. The pooled data of network meta-analysis showed no difference in relative risk (RR) of revision across CoC, CoPc, CoPxl and MoPxl bearings. However, the MoM bearing was demonstrated with a significant higher risk of revision compared with CoC (RR 5.10; 95% CI=1.62 to 16.81), CoPc (RR 4.80; 95% CI=1.29 to 17.09), or MoPxl (RR 3.85; 95% CI=1.16 to 14.29), and the MoPc bearing was indicated with a higher risk of revision compared with CoC (RR 2.83; 95% CI=1.20 to 6.63). The ranking probabilities of the effective interventions also revealed the inferiority of the MoM and MoPc implants in survivorship (both 0%, 95% CI=0% to 0%) compared with CoC (39%, 95% CI=0% to 100%), CoPc (33%, 95% CI=0% to 100%), CoPxl (7%, 95% CI=0% to 100%) or MoPxl (21%, 95% CI=0% to 100%). Conclusions: The present evidence indicated the similar performance in survivorship among CoC, CoPc, CoPxl and MoPxl bearing implants, and that all likely have superiority compared with the MoM and MoPc bearing implants in THA procedures. Long-term RCT data are required to confirm these conclusions and better inform clinical decisions. PMID:26885157

  17. The Painful Total Knee Arthroplasty.

    PubMed

    McDowell, Mitchell; Park, Andrew; Gerlinger, Tad L

    2016-04-01

    There are many causes of residual pain after total knee arthroplasty (TKA). Evaluation and management begins with a comprehensive history and physical examination, followed by radiographic evaluation of the replaced and adjacent joints, as well as previous films of the replaced joint. Further workup includes laboratory analysis, along with a synovial fluid aspirate to evaluate the white blood cell count with differential as well as culture. Advanced imaging modalities may be beneficial when the diagnosis remains unclear. Revision surgery is not advisable without a clear diagnosis, as it may be associated with poor results. PMID:26772940

  18. Total synthesis of (+)-sorangicin A.

    PubMed

    Smith, Amos B; Dong, Shuzhi; Brenneman, Jehrod B; Fox, Richard J

    2009-09-01

    The final synthetic challenges associated with (+)-sorangicin A have been overcome, thus leading to the first total synthesis of this complex macrolide antibiotic. Highlights of the highly convergent synthesis include two Julia-Kocinski olefinations to unite three advanced fragments with high E-stereoselectivity. Critical to the final-stage success was the use of a carefully defined Stille coupling and a Mukaiyama macrolactonization as well as Lewis and protic acid-promoted deprotections carefully designed to suppress E/Z isomerization and/or destruction of the delicate (Z,Z,E)-trienoate linkage. PMID:19663510

  19. Total synthesis of jerangolid A.

    PubMed

    Hanessian, Stephen; Focken, Thilo; Oza, Rupal

    2010-07-16

    The first total synthesis of the antifungal polyketide jerangolid A has been accomplished. Starting with the readily available (R)-Roche ester and (S)-glycidol as chirons, the synthesis involved a highly syn-selective Lewis acid catalyzed 6-endo-trig cyclization for the construction of the dihydropyran subunit. The lactone segment was built through a tandem NaOMe conjugate addition-lactonization reaction, and further functionalized through a sequence consisting of iodination, I-Mg exchange, and hydroxymethylation. Other key steps in the synthesis featured a novel application of a phosphonamide-anion based olefination and a Julia-Kocienski reaction. PMID:20565089

  20. The total synthesis of (+)-migrastatin.

    PubMed

    Gaul, Christoph; Njardarson, Jon T; Danishefsky, Samuel J

    2003-05-21

    The first total synthesis of (+)-migrastatin, a macrolide natural product with interesting antimetastatic properties, has been accomplished. Our concise and flexible approach utilizes a Lewis acid-catalyzed diene aldehyde condensation to install the three contiguous stereocenters and the trisubstituted (Z)-alkene of migrastatin. Construction of the two remaining stereocenters and incorporation of the glutarimide-containing side chain have been achieved via an anti-selective aldol reaction, followed by a Horner-Wadsworth-Emmons olefination. Finally, the assembly of the macrocycle has been realized by a highly (E)-selective ring-closing metathesis. PMID:12785819

  1. Total synthesis of heronapyrrole C.

    PubMed

    Ding, Xiao-Bo; Furkert, Daniel P; Capon, Robert J; Brimble, Margaret A

    2014-01-17

    A flexible total synthesis of the 2-nitropyrrole-derived marine natural product, (+)-heronapyrrole C, is reported. The approach is based on regioselective access to key building blocks containing the rare 4-substituted 2-nitropyrrole motif. Sharpless asymmetric epoxidation and dihydroxylation and a Shi epoxidation were used to introduce the five stereogenic centers of the bis-THF-diol side chain. The N-benzoyloxymethyl (Boz) protecting group was crucial for functionalization of the 2-nitropyrrole moiety and enabling final deprotection under mild conditions. PMID:24351092

  2. Antarctic total ozone in 1958

    SciTech Connect

    Newman, P.A. )

    1994-04-22

    The Antarctic ozone hole results from catalytic destruction of ozone by chlorine radicals. The hole develops in August, reaches its full depth in early October, and is gone by early December of each year. Extremely low total ozone measurements were made at the Antarctic Dumont d'Urville station in 1958. These measurements were derived from spectrographic plates of the blue sky, the moon, and two stars. These Dumont plate data are inconsistent with 1958 Dobson spectrophotometer ozone measurements, inconsistent with present-day Antarctic observations, and inconsistent with meteorological and theoretical information. There is no credible evidence for an ozone hole in 1958.

  3. Characterization of total flare energy

    NASA Technical Reports Server (NTRS)

    Hudson, H. S.

    1986-01-01

    It is concluded that the estimates of total energy in the prime flares lie well below the Active Cavity Radiometer Irradiance Monitor upper limits. This is consistent with our knowledge of the energy distribution in solar flares. Insufficient data exist for us to be very firm about this conclusion, however, and major energetic components could exist undetected, especially in the EUV-XUV and optical bands. In addition, the radiant energy cannot quantitatively be compared at this time with non-radiant terms because of even larger uncertainties in the latter.

  4. Formal total synthesis of (+)-neopeltolide.

    PubMed

    Athe, Sudhakar; Chandrasekhar, Balla; Roy, Saumya; Pradhan, Tapan Kumar; Ghosh, Subhash

    2012-11-01

    This paper describes the formal total synthesis of (+)-neopeltolide, a cytotoxic macrolide isolated from the marine sponge Neopeltidae. The key features of the synthesis include an asymmetric Evans alkylation to fix the C9-methyl center, Jacobsen hydrolytic kinetic resolution of terminal epoxides followed by their regioselective opening to fix the stereocenters at the C11 and C13 positions, respectively, a Pd-catalyzed oxa-Michael reaction to construct the tetrahydropyran ring, and Yamaguchi macrolactonization to form the macrocyclic core of the molecule. PMID:23039136

  5. Development of a totally implantable total artificial heart controller.

    PubMed

    Lee, S H; Choi, W W; Min, B G

    1991-01-01

    Using a one chip microcontroller, 87C196 (One chip EPROM), and an erasable and programmable logic device (EPLD), an implantable control system to drive a pendulum type electromechanical total artificial heart was developed. This control system consists of four parts: a main management system, a motor driver with power regulator, a state monitoring system, and a communication portion. The main system has a speed detector, proportional and integral (PI) control, pulse width modulation (PWM) generation, serial communication, and an analog data processor. Two kinds of power system are used, separated by eight photocoupler arrays to improve system stability. When the performance of each compartment was compared with that of the previously used Z80 microprocessor based control system, good correspondence was shown. Logic power consumption was reduced to one third that of the previous controller. Using mock circulation tests, the overall performance of the control system was evaluated. PMID:1751254

  6. Shenandoah Solar Total Energy Project

    SciTech Connect

    Leonard, J.A.; Hunke, R.W.

    1981-01-01

    The design of the world's first solar total energy plant in the private sector has been completed and construction is underway. The project, a major element of the Department of Energy's Solar Thermal Program, is the Solar Total Energy Project at Shenandoah, Georgia. When operational in early 1982, the solar plant will furnish electrical power, process steam, and other thermal energy to a nearby knitwear factory. The solar system consists of a collector field containing 114 parabolic dish collectors which supply thermal energy at 400/sup 0/C to drive a 400 kW multi-stage Rankine cycle turbine generator. Some steam is extracted from the turbine and supplied to the knitwear manufacturing processes. The system will be grid-connected, and the Georgia Power Company, through a cooperative agreement with DOE, is a participant in the project. Included are: (1) a description of the system and components being installed; (2) a summary of performance testing of the extraction turbine and of four prototype parabolic dish collectors; and (3) a discussion of design considerations and insights which have general applicability to solar thermal system designs.

  7. Total ozone trend over Cairo

    NASA Technical Reports Server (NTRS)

    Hassan, G. K. Y.

    1994-01-01

    A world wide interest in protecting ozone layer against manmade effects is now increasing. Assessment of the ozone depletion due to these activities depends on how successfully we can separate the natural variabilities from the data. The monthly mean values of total ozone over Cairo (30 05N) for the period 1968-1988, have been analyzed using the power spectral analysis technique. The technique used in this analysis does not depend on a pre-understanding of the natural fluctuations in the ozone data. The method depends on increasing the resolution of the spectral peaks in order to obtain the more accurate sinusoidal fluctuations with wavelength equal to or less than record length. Also it handles the possible sinusoidal fluctuations with wavelength equal to or less than record length. The results show that it is possible to detect some of the well known national fluctuations in the ozone record such as annual, semiannual, quasi-biennial and quasi-quadrennial oscillations. After separating the natural fluctuations from the ozone record, the trend analysis of total ozone over Cairo showed that a decrease of about -1.2% per decade has occurred since 1979.

  8. Solar total energy project Shenandoah

    SciTech Connect

    1980-01-10

    This document presents the description of the final design for the Solar Total Energy System (STES) to be installed at the Shenandoah, Georgia, site for utilization by the Bleyle knitwear plant. The system is a fully cascaded total energy system design featuring high temperature paraboloidal dish solar collectors with a 235 concentration ratio, a steam Rankine cycle power conversion system capable of supplying 100 to 400 kW(e) output with an intermediate process steam take-off point, and a back pressure condenser for heating and cooling. The design also includes an integrated control system employing the supervisory control concept to allow maximum experimental flexibility. The system design criteria and requirements are presented including the performance criteria and operating requirements, environmental conditions of operation; interface requirements with the Bleyle plant and the Georgia Power Company lines; maintenance, reliability, and testing requirements; health and safety requirements; and other applicable ordinances and codes. The major subsystems of the STES are described including the Solar Collection Subysystem (SCS), the Power Conversion Subsystem (PCS), the Thermal Utilization Subsystem (TUS), the Control and Instrumentation Subsystem (CAIS), and the Electrical Subsystem (ES). Each of these sections include design criteria and operational requirements specific to the subsystem, including interface requirements with the other subsystems, maintenance and reliability requirements, and testing and acceptance criteria. (WHK)

  9. NAVIGATION IN TOTAL KNEE ARTHROPLASTY

    PubMed Central

    da Mota e Albuquerque, Roberto Freire

    2015-01-01

    Navigation was the most significant advance in instrumentation for total knee arthroplasty over the last decade. It provides surgeons with a precision tool for carrying out surgery, with the possibility of intraoperative simulation and objective control over various anatomical and surgical parameters and references. Since the first systems, which were basically used to control the alignment of bone cutting referenced to the mechanical axis of the lower limb, many other surgical steps have been incorporated, such as component rotation, ligament balancing and arranging the symmetry of flexion and extension spaces, among others. Its efficacy as a precision tool with an effective capacity for promoting better alignment of the lower-limb axis has been widely proven in the literature, but the real value of optimized alignment and the impact of navigation on clinical results and the longevity of arthroplasty have yet to be established.

  10. Total synthesis of bryostatin 1.

    PubMed

    Keck, Gary E; Poudel, Yam B; Cummins, Thomas J; Rudra, Arnab; Covel, Jonathan A

    2011-02-01

    Bryostatin 1 is a marine natural product that is a very promising lead compound because of the potent biological activity it displays against a variety of human disease states. We describe herein the first total synthesis of this agent. The synthetic route adopted is a highly convergent one in which the preformed, heavily functionalized pyran rings A and C are united by "pyran annulation", the TMSOTf-promoted reaction between a hydroxyallylsilane appended to the A-ring fragment and an aldehyde contained in the C-ring fragment, with concomitant formation of the B ring. Further elaborations of the resulting very highly functionalized intermediate include macrolactonization and selective cleavage of just one of five ester linkages present. PMID:21175177

  11. Total synthesis of maoecrystal V.

    PubMed

    Zhang, Wei-Bin; Lin, Guang; Shao, Wen-Bin; Gong, Jian-Xian; Yang, Zhen

    2015-04-01

    Maoecrystal V (1) is a novel diterpenoid, which was originally isolated from the leaves of the Chinese medicinal herb Isodon eriocalyx in 2004 by Sun et al.1 It has been found to be selectively cytotoxic towards HeLa cells, with an IC50 value of 20 ng mL(-1) . Significant research efforts have been devoted to the synthesis of maoecrystal V because of its intriguing biological properties, rarity in nature, and complex structural features. Herein, we describe our recent investigations, which have culminated in the total synthesis of (±)-maoecrystal V. The current strategy involved three key steps for the successful construction of the key tetrahydrofuran oxa-bridge skeleton, including a Wessely oxidative dearomatization, a novel intramolecular Diels-Alder reaction, and a Rh(II) -catalyzed O - H insertion reaction. PMID:25504983

  12. Total Synthesis of Ningalin D

    PubMed Central

    Hamasaki, Akiyuki; Zimpleman, Jeffrey M.; Hwang, Inkyu; Boger, Dale L.

    2008-01-01

    A concise (9 step) and effective (19% overall yield) total synthesis of ningalin D (1a) is disclosed and is based on a key 1,2,4,5-tetrazine ? 1,2-diazine ? pyrrole DielsAlder strategy to assemble a fully substituted pyrrole core central to its structure. Additional highlights of the synthesis include a double Dieckmann condensation to introduce the C and D aryl rings enlisting substituents judiciously placed on the dienophile and intrinsic to the widely used tetrazine 2, a highly effective Suzuki coupling of the resulting C and D phenol triflates for introduction of the sterically demanding F and G aryl rings, and an unusually effective formal oxidative decarboxylation reaction cascade initiated by a Curtius rearrangement to directly provide the biphenylene quinone methide found imbedded in the structure of ningalin D. The cytotoxic and multidrug resistance (MDR) reversal activity of ningalin D, its derivatives, and the key synthetic intermediates are detailed. PMID:16045367

  13. TVD: Total Variation Diminishing code

    NASA Astrophysics Data System (ADS)

    Pen, Ue-Li; Arras, Phil; Wong, ShingKwong

    2013-04-01

    TVD solves the magnetohydrodynamic (MHD) equations by updating the fluid variables along each direction using the flux-conservative, second-order, total variation diminishing (TVD), upwind scheme of Jin & Xin. The magnetic field is updated separately in two-dimensional advection-constraint steps. The electromotive force (EMF) is computed in the advection step using the TVD scheme, and this same EMF is used immediately in the constraint step in order to preserve ??B=0 without the need to store intermediate fluxes. The code is extended to three dimensions using operator splitting, and Runge-Kutta is used to get second-order accuracy in time. TVD offers high-resolution per grid cell, second-order accuracy in space and time, and enforcement of the ??B=0 constraint to machine precision. Written in Fortran, It has no memory overhead and is fast. It is also available in a fully scalable message-passing parallel MPI implementation.

  14. Tribology of total artificial joints.

    PubMed

    Fisher, J; Dowson, D

    1991-01-01

    The tribology of total artificial replacement joints is reviewed. The majority of prosthesis currently implanted comprise a hard metallic component which articulates on ultra high molecular weight polyethylene surface. These relatively hard bearing surfaces operate with a mixed or boundary lubrication regime, which results in wear and wear debris from the ultra high molecular weight polyethylene surface. This debris can contribute to loosening and ultimate failure of the prostheses. The tribological performance of these joints has been considered and a number of factors which may contribute to increased wear rates have been identified. Cushion bearing surfaces consisting of low elastic modulus materials which can articulate with full fluid film lubrication are also described. These bearing surfaces have shown the potential for greatly reducing wear debris. PMID:1840723

  15. Formal total synthesis of aliskiren.

    PubMed

    Peters, Byron K; Liu, Jianguo; Margarita, Cristiana; Andersson, Pher G

    2015-05-01

    The efficient and selective formal total synthesis of aliskiren is described. Aliskiren, a renin inhibitor drug, has received considerable attention, primarily because it is the first of the renin inhibitor drugs to be approved by the FDA. Herein, the formal synthesis of aliskiren by iridium-catalyzed asymmetric hydrogenation of two allylic alcohol fragments is reported. Screening a number of N,P-ligated iridium catalysts yielded two catalysts that gave the highest enantioselectivity in the hydrogenation, which gave the saturated alcohols in 97 and 93?% ee. In only four steps after hydrogenation, the fragments were combined by using the Julia-Kocienski reaction to produce late-stage intermediate in an overall yield of 18?%. PMID:25783891

  16. Total quality management implementation guidelines

    SciTech Connect

    Not Available

    1993-12-01

    These Guidelines were designed by the Energy Quality Council to help managers and supervisors in the Department of Energy Complex bring Total Quality Management to their organizations. Because the Department is composed of a rich mixture of diverse organizations, each with its own distinctive culture and quality history, these Guidelines are intended to be adapted by users to meet the particular needs of their organizations. For example, for organizations that are well along on their quality journeys and may already have achieved quality results, these Guidelines will provide a consistent methodology and terminology reference to foster their alignment with the overall Energy quality initiative. For organizations that are just beginning their quality journeys, these Guidelines will serve as a startup manual on quality principles applied in the Energy context.

  17. Conversion total hip arthroplasty: Primary or revision total hip arthroplasty

    PubMed Central

    Schwarzkopf, Ran; Baghoolizadeh, Mahta

    2015-01-01

    Total hip arthroplasty (THA) is an increasingly common procedure among elderly individuals. Although conversion THA is currently bundled in a diagnosis related group (DRG) with primary THA, there is a lack of literature supporting this classification and it has yet to be identified whether conversion THA better resembles primary or revision THA. This editorial analyzed the intraoperative and postoperative factors and functional outcomes following conversion THA, primary THA, and revision THA to understand whether the characteristics of conversion THA resemble one procedure or the other, or are possibly somewhere in between. The analysis revealed that conversion THA requires more resources both intraoperatively and postoperatively than primary THA. Furthermore, patients undergoing conversion THA present with poorer functional outcomes in the long run. Patients undergoing conversion THA better resemble revision THA patients than primary THA patients. As such, patients undergoing conversion THA should not be likened to patients undergoing primary THA when determining risk stratification and reimbursement rates. Conversion THA procedures should be planned accordingly with proper anticipation of the greater needs both in the operating room, and for in-patient and follow-up care. We suggest that conversion THA be reclassified in the same DRG with revision THA as opposed to primary THA as a step towards better allocation of healthcare resources for conversion hip arthroplasties. PMID:26601055

  18. Conversion total hip arthroplasty: Primary or revision total hip arthroplasty.

    PubMed

    Schwarzkopf, Ran; Baghoolizadeh, Mahta

    2015-11-18

    Total hip arthroplasty (THA) is an increasingly common procedure among elderly individuals. Although conversion THA is currently bundled in a diagnosis related group (DRG) with primary THA, there is a lack of literature supporting this classification and it has yet to be identified whether conversion THA better resembles primary or revision THA. This editorial analyzed the intraoperative and postoperative factors and functional outcomes following conversion THA, primary THA, and revision THA to understand whether the characteristics of conversion THA resemble one procedure or the other, or are possibly somewhere in between. The analysis revealed that conversion THA requires more resources both intraoperatively and postoperatively than primary THA. Furthermore, patients undergoing conversion THA present with poorer functional outcomes in the long run. Patients undergoing conversion THA better resemble revision THA patients than primary THA patients. As such, patients undergoing conversion THA should not be likened to patients undergoing primary THA when determining risk stratification and reimbursement rates. Conversion THA procedures should be planned accordingly with proper anticipation of the greater needs both in the operating room, and for in-patient and follow-up care. We suggest that conversion THA be reclassified in the same DRG with revision THA as opposed to primary THA as a step towards better allocation of healthcare resources for conversion hip arthroplasties. PMID:26601055

  19. Instability following total knee arthroplasty.

    PubMed

    Rodriguez-Merchan, E Carlos

    2011-10-01

    Background Knee prosthesis instability (KPI) is a frequent cause of failure of total knee arthroplasty. Moreover, the degree of constraint required to achieve immediate and long-term stability in total knee arthroplasty (TKA) is frequently debated. Questions This review aims to define the problem, analyze risk factors, and review strategies for prevention and treatment of KPI. Methods A PubMed (MEDLINE) search of the years 2000 to 2010 was performed using two key words: TKA and instability. One hundred and sixty-five initial articles were identified. The most important (17) articles as judged by the author were selected for this review. The main criteria for selection were that the articles addressed and provided solutions to the diagnosis and treatment of KPI. Results Patient-related risk factors predisposing to post-operative instability include deformity requiring a large surgical correction and aggressive ligament release, general or regional neuromuscular pathology, and hip or foot deformities. KPI can be prevented in most cases with appropriate selection of implants and good surgical technique. When ligament instability is anticipated post-operatively, the need for implants with a greater degree of constraint should be anticipated. In patients without significant varus or valgus malalignment and without significant flexion contracture, the posterior cruciate ligament (PCL) can be retained. However, the PCL should be sacrificed when deformity exists particularly in patients with rheumatoid arthritis, previous patellectomy, previous high tibial osteotomy or distal femoral osteotomy, and posttraumatic osteoarthritis with disruption of the PCL. In most cases, KPI requires revision surgery. Successful outcomes can only be obtained if the cause of KPI is identified and addressed. Conclusions Instability following TKA is a common cause of the need for revision. Typically, knees with deformity, rheumatoid arthritis, previous patellectomy or high tibial osteotomy, and posttraumatic arthritis carry higher risks of post-operative instability and are indications for more constrained TKA designs. Instability following TKA usually requires revision surgery which must address the cause of the instability for success. PMID:23024625

  20. Total quality management program planning

    SciTech Connect

    Thornton, P.T.; Spence, K.

    1994-05-01

    As government funding grows scarce, competition between the national laboratories is increasing dramatically. In this era of tougher competition, there is no for resistance to change. There must instead be a uniform commitment to improving the overall quality of our products (research and technology) and an increased focus on our customers` needs. There has been an ongoing effort to bring the principles of total quality management (TQM) to all Energy Systems employees to help them better prepare for future changes while responding to the pressures on federal budgets. The need exists for instituting a vigorous program of education and training to an understanding of the techniques needed to improve and initiate a change in organizational culture. The TQM facilitator is responsible for educating the work force on the benefits of self-managed work teams, designing a program of instruction for implementation, and thus getting TQM off the ground at the worker and first-line supervisory levels so that the benefits can flow back up. This program plan presents a conceptual model for TQM in the form of a hot air balloon. In this model, there are numerous factors which can individually and collectively impede the progress of TQM within the division and the Laboratory. When these factors are addressed and corrected, the benefits of TQM become more visible. As this occurs, it is hoped that workers and management alike will grasp the ``total quality`` concept as an acceptable agent for change and continual improvement. TQM can then rise to the occasion and take its rightful place as an integral and valid step in the Laboratory`s formula for survival.

  1. Dynaflex prosthesis in total phalloplasty.

    PubMed

    Hage, J J

    1997-02-01

    Because of the high rate of complications and because voiding while standing is a priority for most female-to-male transsexuals, until recently, I have refrained from implantation of a rigidity prosthesis in total phalloplasty. However, promising results have been obtained with self-contained Dynaflex hydraulic penile implants. The results and complications observed in my first five cases are reported in order to help prevent failure in future cases. I advocate implantation as a secondary procedure after the neophallus has gained sensitivity. The penile prosthesis should be covered by a Dacron prosthesis to ensure optimal encapsulation and collagen ingrowth. Since the neophallus girth will not allow for two prostheses to be implanted, and because properly serviceable crus penis is lacking in female-to-male transsexuals, I further advocate fixation of the one cylinder to the pubic symphysis. For insertion, the neoscrotal approach is superior. I maintain that combination of a neourethra and a rigidity prosthesis in one neophallus remains a challenge, both to the patient and to the surgeon. PMID:9030158

  2. Pollution prevention through total quality

    SciTech Connect

    Stoltz, D.L.; Byrant, M.G.; Eggers, D.M.; Gough, R.W.; Schlosberg, W.H.

    1993-05-01

    Application of Total Quality to AlliedSignal Inc., Kansas City Division`s (KCD) Pollution Prevention Program has created a dynamic and focused effort to significantly reduce process inefficiencies and waste generation. KCD is demonstrating TQ`s usefulness by empowering associates and obtaining their buy-in and ownership of pollution prevention principles. Specific pollution prevention working groups include: establishing a comprehensive recycling process; (2) capitalizing on Environmentally Conscious Manufacturing (ECM) expertise; and (3) encouraging the internal implementation of ECM. TQ produces the performance results that promote and sustain plant-wide pollution prevention goals and activities. KCD uses AlliedSignall`s nine step ``Process Improvement Problem/Solving Model`` (Appendix A). Although this program only formally began within the past year, many of the tools have been used over the last eight years to achieve pollution prevention objectives. This paper focuses on the new attitude and gives examples of how each of the nine steps is being used in the KCD Pollution Prevention Program. This paper describe s each step of the process and provides specific pollution prevention examples.

  3. Pollution prevention through total quality

    SciTech Connect

    Stoltz, D.L.; Byrant, M.G.; Eggers, D.M.; Gough, R.W.; Schlosberg, W.H.

    1993-05-01

    Application of Total Quality to AlliedSignal Inc., Kansas City Division's (KCD) Pollution Prevention Program has created a dynamic and focused effort to significantly reduce process inefficiencies and waste generation. KCD is demonstrating TQ's usefulness by empowering associates and obtaining their buy-in and ownership of pollution prevention principles. Specific pollution prevention working groups include: establishing a comprehensive recycling process; (2) capitalizing on Environmentally Conscious Manufacturing (ECM) expertise; and (3) encouraging the internal implementation of ECM. TQ produces the performance results that promote and sustain plant-wide pollution prevention goals and activities. KCD uses AlliedSignall's nine step Process Improvement Problem/Solving Model'' (Appendix A). Although this program only formally began within the past year, many of the tools have been used over the last eight years to achieve pollution prevention objectives. This paper focuses on the new attitude and gives examples of how each of the nine steps is being used in the KCD Pollution Prevention Program. This paper describe s each step of the process and provides specific pollution prevention examples.

  4. Total hydrocarbon analyzer evaluation study

    SciTech Connect

    Shamat, N. ); Crumpler, E. ); Roddan, A. )

    1991-10-01

    Measuring and controlling organic emissions from incineration processes has become a major environmental concern in recent years. The US Environmental Protection Agency (EPA) recently proposed a regulation for sewage sludge incinerators under section 405(d) of the Clean Water Act that will require all sludge incinerators to monitor total hydrocarbon emissions (THCs) on a continuous basis. Such a requirement would be part of National Pollutant Discharge Elimination (NPDES) permits and site-specific THC limits would be established for facilities based on a risk assessment of organic emissions. Before EPA can finalize the proposed requirement, THC monitoring must be successfully conducted in a plant environment and the system required by any final regulation must be kept in operation so that facilities can comply with their permits. The Metropolitan Waste Control Commission (MWCC) in St. Paul, Minn., and Rosemount Analytical Division in La Habre, Calif., entered into a joint agreement with EPA to demonstrate a hot' THC monitoring system to detect THCs in stack gases. The objectives of the study are to determine the feasibility of THC monitoring of sludge incinerator emissions; evaluate the long term reliability, cost of operation, and consistency of a continuous THC monitoring system in an incinerator environment; and determine the correlation of THC stack concentration to incinerator and scrubber operating conditions, carbon monoxide concentration, and specific VOC emissions.

  5. Enantioselective total synthesis of (-)-acutumine.

    PubMed

    Li, Fang; Tartakoff, Samuel S; Castle, Steven L

    2009-12-01

    An account of the total synthesis of the tetracyclic alkaloid (-)-acutumine is presented. A first-generation approach to the spirocyclic subunit was unsuccessful as a result of incorrect regioselectivity in a radical cyclization. However, this work spawned a second-generation strategy in which the spirocycle was fashioned via a radical-polar crossover reaction. This process merged an intramolecular radical conjugate addition with an enolate hydroxylation and created two stereocenters with excellent diastereoselectivity. The reaction was promoted by irradiation with a sunlamp, and a ditin reagent was required for aryl radical formation. These facts suggest that the substrate may function as a sensitizer, thereby facilitating homolytic cleavage of the ditin reagent. The propellane motif of the target was then installed via annulation of a pyrrolidine ring onto the spirocycle. The sequence of reactions used included a phenolic oxidation, an asymmetric ketone allylation mediated by Nakamura's chiral allylzinc reagent, an anionic oxy-Cope rearrangement, a one-pot ozonolysis-reductive amination, and a Lewis acid promoted cyclization of an amine onto an alpha,beta-unsaturated dimethyl ketal. Further studies of the asymmetric ketone allylation demonstrated the ability of the Nakamura reagent to function well in a mismatched situation. A TiCl(4)-catalyzed regioselective methyl enol etherification of a 1,3-diketone completed the synthesis. PMID:19904909

  6. Total Petroleum Hydrocarbons (TPH): ToxFAQs

    MedlinePLUS

    ... a state: This map displays locations where Total Petroleum Hydrocarbons (TPH) is known to be present. On ... I get more information? ToxFAQs TM for Total Petroleum Hydrocarbons (TPH) ( Hidrocarburos Totales de Petróleo (TPH) ) August ...

  7. Total joint replacement preadmission programs.

    PubMed

    Messer, B

    1998-01-01

    Patients begin to formulate their expectations of the postoperative hospitalization during the preadmission program. The challenge is to better understand the factors patients consider when formulating judgments about the quality of preadmission education. For example, it may be that perceptions of the preadmission program are influenced by what patients believe about their postoperative pain and functional abilities. Specific attention needs to be given both preoperatively and postoperatively to instructing patients on realistic expectations for recovery. One other method of measuring patient outcomes is with the Health Status Profile (SF-36) (Response Healthcare Information Management, 1995). The SF-36 approach emphasizes the outcome of medical care as the patient sees it, in addition to a clinical evaluation of successful health care. This form is currently initiated in the physician's office and returned for scanning at the preadmission class. The patient then completes another SF-36 at 6 months and every year thereafter to compare measurable outcomes. Patients intending to have elective total joint replacements experience anxiety and require much support and education. An effective preadmission program is a major investment in a patient's recovery, as well as a unique marketing tool to customers. Preadmission programs can be viewed as an opportunity to enhance customer satisfaction. Preadmission clinics are an excellent means for nurses to improve the quality of patient care through patient education. the overall goal of preadmission testing programs is to ensure patient preparedness while increasing quality health care and overall customer satisfaction. To enhance program effectiveness, health care providers must lead collaborative efforts to improve the efficiency of systems. PMID:9601410

  8. CALIFORNIA CITIES WITH 1990 & 2000 POPULATION TOTALS

    EPA Science Inventory

    Point locations represent cities with Census 2000 population totals and 1990 Census population totals. Cities represent Census Designated Place (CDP) as classified by the US Bureau of the Census. CDP comprise densely settled concentrations of population that are identifiable by...

  9. ARIZONA CITIES WITH 1990 & 2000 POPULATION TOTALS

    EPA Science Inventory

    Point locations represent cities with Census 2000 population totals and 1990 Census population totals. Cities represent Census Designated Place (CDP) as classified by the US Bureau of the Census. CDP comprise densely settled concentrations of population that are identifiable by...

  10. NEVADA CITIES WITH 1990 & 2000 POPULATION TOTALS

    EPA Science Inventory

    Point locations represent cities with Census 2000 population totals and 1990 Census population totals. Cities represent Census Designated Place (CDP) as classified by the US Bureau of the Census. CDP comprise densely settled concentrations of population that are identifiable by...

  11. HAWAII CITIES WITH 1990 & 2000 POPULATION TOTALS

    EPA Science Inventory

    Point locations represent cities with Census 2000 population totals and 1990 Census population totals. Cities represent Census Designated Place (CDP) as classified by the US Bureau of the Census. CDP comprise densely settled concentrations of population that are identifiable by...

  12. Recommended Amounts of Total starchy vegetables

    Cancer.gov

    Recommended Amounts of Total starchy vegetables Table B6. Total starchy vegetables: Estimated percentage of persons below, at, or above recommendation1 Age (years) N Mean (SE) % with intake below recommendation (SE) % with intake meeting recommendation

  13. Deformation of the Durom Acetabular Component and Its Impact on Tribology in a Cadaveric Model—A Simulator Study

    PubMed Central

    Gu, Yanqing; Wang, Qing; Cui, Weiding; Fan, Weimin

    2012-01-01

    Background Recent studies have shown that the acetabular component frequently becomes deformed during press-fit insertion. The aim of this study was to explore the deformation of the Durom cup after implantation and to clarify the impact of deformation on wear and ion release of the Durom large head metal-on-metal (MOM) total hips in simulators. Methods Six Durom cups impacted into reamed acetabula of fresh cadavers were used as the experimental group and another 6 size-paired intact Durom cups constituted the control group. All 12 Durom MOM total hips were put through a 3 million cycle (MC) wear test in simulators. Results The 6 cups in the experimental group were all deformed, with a mean deformation of 41.78±8.86 µm. The average volumetric wear rate in the experimental group and in the control group in the first million cycle was 6.65±0.29 mm3/MC and 0.89±0.04 mm3/MC (t = 48.43, p = 0.000). The ion levels of Cr and Co in the experimental group were also higher than those in the control group before 2.0 MC. However there was no difference in the ion levels between 2.0 and 3.0 MC. Conclusions This finding implies that the non-modular acetabular component of Durom total hip prosthesis is likely to become deformed during press-fit insertion, and that the deformation will result in increased volumetric wear and increased ion release. Clinical Relevance This study was determined to explore the deformation of the Durom cup after implantation and to clarify the impact of deformation on wear and ion release of the prosthesis. Deformation of the cup after implantation increases the wear of MOM bearings and the resulting ion levels. The clinical use of the Durom large head prosthesis should be with great care. PMID:23144694

  14. Prosthetic Design in Total Wrist Arthroplasty.

    PubMed

    Kennedy, Colin D; Huang, Jerry I

    2016-01-01

    Total wrist arthroplasty (TWA) provides a motion-preserving alternative to total wrist arthrodesis for low-demand patients with debilitating pancarpal arthritis. The earlier generation total wrist implants had high complication and failure rates. Advances in prosthetic design have contributed to improved clinical outcomes and implant survivorship. The current fourth-generation implants allow for expansion of indications for TWA. Careful patient selection remains critical; patients with high-demand lifestyles and poor bone stock may not be candidates. Long-term studies on implant survival and patient outcomes are critical for the current generation total wrist implants in assessing their long-term value compared with total wrist arthrodesis. PMID:26614934

  15. Defense meteorological satellite measurements of total ozone

    NASA Technical Reports Server (NTRS)

    Lovill, J. E.; Ellis, J. S.; Luther, F. M.; Sullivan, T. J.; Weichel, R. L.

    1982-01-01

    A multichannel filter radiometer (MFR) on Defense Meteorological Satellites (DMS) that measured total ozone on a global-scale from March 1977 - February 1980 is described. The total ozone data measured by the MFR were compared with total ozone data taken by surfaced-based Dobson spectrophotometers. When comparisons were made for five months, the Dobson spectrophotometer measured 2-5% more total ozone than the MFR. Comparisons between the Dobson spectrophotometer and the MFR showed a reduced RMS difference as the comparisons were made at closer proximity. A Northern Hemisphere total ozone distribution obtained from MFR data is presented.

  16. Trends in total column ozone measurements

    NASA Technical Reports Server (NTRS)

    Rowland, F. S.; Angell, J.; Attmannspacher, W.; Bloomfield, P.; Bojkov, R. D.; Harris, N.; Komhyr, W.; Mcfarland, M.; Mcpeters, R.; Stolarski, R. S.

    1989-01-01

    It is important to ensure the best available data are used in any determination of possible trends in total ozone in order to have the most accurate estimates of any trends and the associated uncertainties. Accordingly, the existing total ozone records were examined in considerable detail. Once the best data set has been produced, the statistical analysis must examine the data for any effects that might indicate changes in the behavior of global total ozone. The changes at any individual measuring station could be local in nature, and herein, particular attention was paid to the seasonal and latitudinal variations of total ozone, because two dimensional photochemical models indicate that any changes in total ozone would be most pronounced at high latitudes during the winter months. The conclusions derived from this detailed examination of available total ozone can be split into two categories, one concerning the quality and the other the statistical analysis of the total ozone record.

  17. Free radical scavenging activity, total phenolic content, total antioxidant status, and total oxidant status of endemic Thermopsis turcica.

    PubMed

    Aksoy, Laine; Kolay, Erdi; A??ln, Yasin; Aslan, Zeyneb; Karg?o?lu, Mustafa

    2013-07-01

    Thermopsis turcica, endemic to Turkey, is in danger of extinction. Studies on this species are very few due to the fact that it was only discovered in 1983 and grows in a small circumscribed area in Turkey. In this study, free radical scavenging activity, total phenolic content, total oxidant status (TOS), and total antioxidant status (TAS) of methanol (TTM) and acetone (TTA) extracts of T. turcica were measured spectroscopically. Free radical scavenging activity was determined according to the elimination of DPPH radicals and total phenol content was determined by the Folin-Ciocalteu reaction. Total oxidant status (TOS) and total antioxidant status (TAS) were measured with commercially available kits. Methanol and acetone extracts of T. turcica were found to have a specific radical scavenging effect. This effect was found to be related to the total phenolic content of the extracts. Since the TTA had a higher phenolic content than the methanol extract, it had a stronger radical scavenging effect. In addition, the total antioxidant capacity of the methanol extract was observed to be higher than that of its acetone counterpart. As a result, due to its antioxidative properties, T. turcica is thought to be a natural source of antioxidants. PMID:23961240

  18. Total solar eclipse of 3 November 1994

    NASA Technical Reports Server (NTRS)

    Espenak, Fred; Anderson, Jay

    1993-01-01

    A total eclipse of the Sun will be visible from the southern half of the Western Hemisphere on 3 November 1994. The path of the Moon's shadow passes through Peru, Chile, Bolivia, Paraguay, and Brazil. Detailed predictions for this event are presented and include tables of geographic coordinates of the path of totality, local circumstances for hundreds of cities, maps of the path of total and partial eclipse, weather prospects, and the lunar limb profile.

  19. Water-Cooled Total-Temperature Probe

    NASA Technical Reports Server (NTRS)

    Lagen, Nicholas T.; Reece, Garland D.

    1992-01-01

    Water-cooled supersonic total-pressure, static-pressure, and total-temperature probes developed to study high-temperature jet plumes. Total-temperature probe tested up to 2,000 degrees F incorporates annular cooling system up to thermocouple lead. Lead extends into test chamber to sense temperature of supersonic external flow. Design novel and significant. Applicable in development of jet engines and in research on fast flows of hot gases.

  20. Computation of orbits using total energy

    NASA Technical Reports Server (NTRS)

    Bond, Victor R.; Mulcihy, David D.

    1988-01-01

    The computation of orbits can be done more efficiently by the use of any of several new formulations of the perturbed two body problem which consider the total energy of the orbital system as one of the dependent variables. The total energy is the osculating two body energy plus the potential energy due to perturbing masses. The use of the total energy as the dependent variable instead of the two body energy is a relatively new idea. The advantage of using total energy arises from the fact that the more perturbing potential energy that is accounted for in the total energy variable, the more nearly constant is the total energy. In fact, except for dissipative forces such as drag, the only reason for the total energy not being constant is the rotation or revolution of the perturbing mass. This near constancy of the total energy has the effect of inhibiting error growth during numerical solution. This paper will present the results of an application of total energy formulation to the problem of the precise computation of orbits.

  1. Generalized gravitational entropy from total derivative action

    NASA Astrophysics Data System (ADS)

    Dong, Xi; Miao, Rong-Xin

    2015-12-01

    We investigate the generalized gravitational entropy from total derivative terms in the gravitational action. Following the method of Lewkowycz and Maldacena, we find that the generalized gravitational entropy from total derivatives vanishes. We compare our results with the work of Astaneh, Patrushev, and Solodukhin. We find that if total derivatives produced nonzero entropy, the holographic and the field-theoretic universal terms of entanglement entropy would not match. Furthermore, the second law of thermodynamics could be violated if the entropy of total derivatives did not vanish.

  2. Wear mechanisms and improvements of wear resistance in cobalt-chromium alloy femoral components in artificial total knee joints

    NASA Astrophysics Data System (ADS)

    Que, Like

    Wear is one of the major causes of artificial total knee arthroplasty (TKA) failure. Wear debris can cause adverse reactions to the surrounding tissue which can ultimately lead to loosening of the prosthesis. The wear behavior of UHMWPE tibial components have been studied extensively, but relatively little attention has been paid to the CoCrMo femoral component. The goal of the present study was to investigate the wear mechanisms of CoCrMo femoral components, to study the effect of CoCrMo alloy surface roughness on the wear of UHMWPE, and to determine the effect of heat treatments on the wear resistance of the CoCrMo implant alloys. The surface roughness of twenty-seven retrieved CoCrMo femoral components was analyzed. A multiple station wear testing machine and a wear fixture attached to an MTS 858 bionix system were built and used for in vitro wear studies of the CoCrMo/UHMWPE bearing couple. Solution and aging treatments were applied to the CoCrMo alloys. A white light interference surface profilometer (WLISP) and a scanning electron microscope (SEM) were used to measure the surface roughness and to study wear mechanisms of CoCrMo alloy. An optical microscope was used for alloy microstructure study. X-ray diffraction tests were performed to identify alloy phase transformation after aging. The micro-structure, hardness, and wear resistance of the alloys were studied. Surface roughness was used to quantify alloy wear, and the minimum number of surface roughness measurements required to obtain a reliable and repeatable characterization of surface roughness for a worn alloy surface was determined. The surfaces of the retrieved CoCrMo femoral components appeared to be damaged by metal particles embedded in the UHMWPE tibial component and metal-on-metal wear due to UHMWPE tibial component through-wear. Surface roughness of the femoral components was not correlated with patient age, weight, sex, or length of implantation. In vitro wear tests showed that when the CoCrMo alloy surface roughness was higher than 0.022 mum Ra (surface roughness average), UHMWPE wear increased with increasing CoCrMo alloy surface roughness. Bone and poly(methyl methacrylate) (PMMA) bone cement abrasive particles created scratches on the alloy via a ploughing mechanism, and resulted in significantly rougher surfaces than controls without particles (P < 0.01). Solution treatments at 1230sp°C and 1245sp°C reduced the hardness and wear resistance of the as-cast F75 CoCrMo alloy. Aging at 700sp°C caused recrystallization of the forged F799 alloy and improved wear resistance. Thermo-mechanical treatments have the potential to increase the lifetime of artificial joints by increasing the wear resistance of CoCrMo components.

  3. 75 FR 22418 - FHA TOTAL Mortgage Scorecard

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-04-28

    ... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF HOUSING AND URBAN DEVELOPMENT FHA TOTAL Mortgage Scorecard AGENCY: Office of the Chief Information Officer, HUD... following information: Title of Proposal: FHA TOTAL Mortgage Scorecard. OMB Approval Number: 2502-0556....

  4. Total Quality Management in Education. Second Edition.

    ERIC Educational Resources Information Center

    Sallis, Edward

    Quality is at the top of most agendas, and improving quality is probably the most important task facing any institution. In addition, quality is difficult to define or measure. This book, the second edition of "Total Quality Management in Education," introduces the key concepts of Total Quality Management (TQM) and demonstrates how they can be put

  5. EVALUATION OF TOTAL ORGANIC EMISSIONS ANALYSIS METHODS

    EPA Science Inventory

    The rationale and supporting experimental data for revising EPA's 1996 "Guidance for Total Organics" are summarized in this document. It reports the results of reseach and investigation of improvements to the Total Organic Emissions (TOE) guidance used by EPA to measure recovera...

  6. Total to withdraw from Qatar methanol - MTBE?

    SciTech Connect

    1996-05-01

    Total is rumored to be withdrawing from the $700-million methanol and methyl tert-butyl ether (MTBE) Qatar Fuel Additives Co., (Qafac) project. The French company has a 12.5% stake in the project. Similar equity is held by three other foreign investors: Canada`s International Octane, Taiwan`s Chinese Petroleum Corp., and Lee Change Yung Chemical Industrial Corp. Total is said to want Qafac to concentrate on methanol only. The project involves plant unit sizes of 610,000 m.t./year of MTBE and 825,000 m.t./year of methanol. Total declines to comment.

  7. Total solar eclipse of 1995 October 24

    NASA Technical Reports Server (NTRS)

    Espenak, Fred; Anderson, Jay

    1994-01-01

    A total eclipse of the sun will be visible from Asia and the Pacific Ocean on 24 Oct. 1995. The path of the moon's shadow begins in the Middle East and sweeps across India, Southeast Asia, and the waters of the Indonesian archipelago before ending at sunset in the Pacific. Detailed predictions for this event are presented and include besselian elements, geographic coordinates of the path of totality, physical ephemeris of the umbra, topocentric limb profile corrections, local circumstances for 400 cities, maps of the eclipse path, weather prospects, the lunar limb profile, and the sky during totality.

  8. [Total amitraz residues in bee honeys].

    PubMed

    Hemmerling, C; Augustyniak, B; Risto, C

    1991-01-01

    A total of 330 bee honey samples was analysed in 1986-1990, and the results are reported. Analysis was performed according to the method for the amitraz total residue determination by hydrolysis and steam distillation as described. 60% of the honeys were practically not contamined (total residue content amounting to 0.01 mg/kg), 8.5% of the honeys contained more than 0.05 mg/kg. Maximal values of 0.2-0.5 mg/kg were stated. 54% of the rape-honeys contained more than 0.01 mg/kg, 19% more than 0.05 mg/kg. PMID:1800907

  9. Total body calcium analysis. [neutron irradiation

    NASA Technical Reports Server (NTRS)

    Lewellen, T. K.; Nelp, W. B.

    1974-01-01

    A technique to quantitate total body calcium in humans is developed. Total body neutron irradiation is utilized to produce argon 37. The radio argon, which diffuses into the blood stream and is excreted through the lungs, is recovered from the exhaled breath and counted inside a proportional detector. Emphasis is placed on: (1) measurement of the rate of excretion of radio argon following total body neutron irradiation; (2) the development of the radio argon collection, purification, and counting systems; and (3) development of a patient irradiation facility using a 14 MeV neutron generator. Results and applications are discussed in detail.

  10. Total Solar Eclipse--A Caribbean Adventure.

    ERIC Educational Resources Information Center

    Green, Steven; Tunstall, Louisa; Tunstall, Neil

    1999-01-01

    Describes the experiences of two high school students who traveled to the Caribbean island of Curacao to view a total solar eclipse and prepare methods for teaching classmates about the eclipse the following school year. (Author/WRM)

  11. Need total sulfur content? Use chemiluminescence

    SciTech Connect

    Kubala, S.W.; Campbell, D.N.; DiSanzo, F.P.

    1996-09-01

    Regulations issued by the United States Environmental Protection Agency require petroleum refineries to reduce or control the amount of total sulfur present in their refined products. These legislative requirements have led many refineries to search for online instrumentation that can produce accurate and repeatable total sulfur measurements within allowed levels. Several analytical methods currently exist to measure total sulfur content. They include X-ray fluorescence (XRF), microcoulometry, lead acetate tape, and pyrofluorescence techniques. Sulfur-specific chemiluminescence detection (SSCD) has recently received much attention due to its linearity, selectivity, sensitivity, and equimolar response. However, its use has been largely confined to the area of gas chromatography. This article focuses on the special design considerations and analytical utility of an SSCD system developed to determine total sulfur content in gasoline. The system exhibits excellent linearity and selectivity, the ability to detect low minimum levels, and an equimolar response to various sulfur compounds. 2 figs., 2 tabs.

  12. [Total situs inversus associated with Lutembacher syndrome].

    PubMed

    Malkun, C; Alvarado, M; Hurtado, R; Badui, E; Taveras, M; Rivera, C

    1986-01-01

    We describe a 19 years old patient with total situs inversus in association with Lutembacher's syndrome, and surgical intervention. Our review of the literature, did not disclosed any similar case. PMID:2948456

  13. Solar Total Energy Project construction cost history

    SciTech Connect

    Hunke, R.W.; Pappas, G.N.

    1983-03-01

    A solar energy project using parabolic dish collectors was designed, fabricated, and installed near Shenandoah, GA. A cost history of the construction of the Solar Total Energy Project is presented. Costs are broken down into the various project elements.

  14. Total lymphoid irradiation in alloimmunity and autoimmunity

    SciTech Connect

    Strober, S.

    1987-12-01

    Total lymphoid irradiation has been used as an immunosuppressive regimen in autoimmune disease and organ transplantation. The rationale for its use originated from studies of patients with Hodgkin disease, in whom this radiotherapy regimen was noted to induce profound and long-lasting immune suppression and yet was well tolerated, with few long-term side effects. Total lymphoid irradiation is a unique immunosuppressive regimen that produces a selective (and long-lasting) reduction in the number and function of helper T cells and certain subsets of B cells. Conventional immunosuppressive drugs show little selectivity, and their effects are short-lived. The most important aspect of total lymphoid irradiation is the potential for achieving transplantation tolerance and permanent remissions in autoimmune disease in laboratory animals. Attempts are being made to achieve similar goals in humans given total lymphoid irradiation, so that immunosuppressive drugs can be ultimately withdrawn from transplant recipients and patients with lupus nephritis. 28 references.

  15. Total synthesis and structural revision of hericerin.

    PubMed

    Kobayashi, Shoji; Inoue, Tomoharu; Ando, Ami; Tamanoi, Hidetsugu; Ryu, Ilhyong; Masuyama, Araki

    2012-07-01

    The total synthesis of hericerin, a pollen growth inhibitor from Hericium erinaceum, was achieved. We found that the reported structure of hericerin should be revised to be the carbonyl regioisomer. PMID:22670711

  16. UNDERSTANDING CHILDREN'S TOTAL DIETARY EXPOSURE TO PESTICIDES

    EPA Science Inventory

    Recent residential monitoring studies have demonstrated that significant portion of total exposure of infants and children to environmental contaminants can result from contamination of food in the home. Children's foods become contaminated through handling and contact with surf...

  17. Outdoor Activities for a Total Lunar Eclipse

    ERIC Educational Resources Information Center

    Glenn, William H.

    1977-01-01

    Describes several activities involving a total eclipse of the moon. Included are observations with binoculars, naked eye, and telescope; timing activities and observations of color changes during penumbral and umbral phases; and photography activities. (CS)

  18. Total Synthesis of the Proposed Banyasin A

    NASA Astrophysics Data System (ADS)

    Gao, Xuguang; Ren, Qi; Choi, Sun; Xu, Zhengshuang; Ye, Tao

    2015-03-01

    The first total synthesis of four possible isomers of a molecule possessing the stereochemistry proposed for banyasin A is described. The structure synthesized appears to be different from that of the natural product.

  19. Total antioxidant capacity of the Korean diet

    PubMed Central

    Han, Jeong-Hwa; Lee, Hye-Jin; Cho, Mi Ran; Chang, Namsoo; Kim, Yuri; Oh, Se-Young

    2014-01-01

    BACKGROUND/OBJECTIVES The objective of this study was to measure and/or estimate the total antioxidant capacity of the Korean diet. MATERIALS/METHODS Eighty-one plant foods that were expected to exhibit rather high antioxidant activities were selected from the Korean diet using the Fifth Korean National Health and Nutrition Survey (KNHANES V). These foods were categorized into 11 food groups: cereals, potatoes, legumes, nuts, vegetables, kimchies, mushrooms, fruits, fruit juices, sea weeds, and oils. The foods were mixed in the proportions specified in traditional Korean recipes and analyzed. The measured indicators for antioxidant capacities were total phenolics, 2,2-diphenyl-1-picrylhydrazyl (DPPH), oxygen radical absorbance capacity (ORAC), and Trolox equivalent antioxidant capacity (TEAC). RESULTS Total phenolics were high in the fruit juices, nuts, vegetables, and fruits; and the average DPPH, ORAC, and TEAC values were high in the vegetables, fruits, fruit juices, and nuts. The correlation coefficient between the content of total phenolics of each food and the in vitro antioxidant capacity was relatively high at 0.851. The intake of total phenolics per capita per day in the Republic of Korea was estimated to be 127 mg. The total dietary antioxidant capacity (TDAC) values, which were obtained from the total antioxidant capacity of each food, taking into account the intake of each food, were 20,763, 54,335, and 876.4 mol of Trolox equivalents using the DPPH, ORAC, and TEAC methods, respectively. The food group that contributed the most to the Korean TDAC was cereals at 39.7%, followed by fruits and vegetables at 27.8% and 13.9%, respectively. The contribution of legumes, nuts, fruit juices, and mushrooms was quite minimal at less than 2% each. CONCLUSIONS The content of total phenolics and the antioxidant capacity of the Korean diet are significantly correlated and the high contributing food groups are cereals, fruits, and vegetables. PMID:24741403

  20. Photoproduction total cross section and shower development

    NASA Astrophysics Data System (ADS)

    Cornet, F.; Garca Canal, C. A.; Grau, A.; Pancheri, G.; Sciutto, S. J.

    2015-12-01

    The total photoproduction cross section at ultrahigh energies is obtained using a model based on QCD minijets and soft-gluon resummation and the ansatz that infrared gluons limit the rise of total cross sections. This cross section is introduced into the Monte Carlo system AIRES to simulate extended air showers initiated by cosmic ray photons. The impact of the new photoproduction cross section on common shower observables, especially those related to muon production, is compared with previous results.

  1. Proximal tibial fracture following total knee arthroplasty.

    PubMed

    Krause, Heike; Dunleavy, Kim

    2011-09-01

    The patient was a 74-year-old man, with a history of total knee arthoplasty 14 years earlier, after having sustained a pathological fracture of the proximal diaphysis of the left tibia following a fall. Given the unstable nature of the fracture and the severe osteolysis noted below the total knee arthroplasty, surgical management 1 day after the fall entailed packing cancellous bone graft into the defect and realigning the fracture. PMID:21885911

  2. Effects of xenobiotics on total antioxidant capacity

    PubMed Central

    2012-01-01

    The objective of this article was to review the effects of xenobiotics on total antioxidant capacity (TAC). Measurement of TAC is appropriate for evaluation of the total antioxidant defenses of blood, cells, and different kinds of tissues and organs. TAC is reduced by alcoholism, smoking, and exposure to radiation, herbicides, carbon monoxide, carbon tetrachloride, lead, arsenic, mercury, cadmium, aluminum, and other toxic elements. The test is also an important tool in evaluating environmental and occupational exposure. PMID:23554550

  3. Total energies of improved quasicrystal models

    SciTech Connect

    Phillips, R.; Deng, H.; Carlsson, A.E.; Daw, M.S. )

    1991-11-25

    The first electronic total-energy calculations are performed on a 6D-3D projection model for the TiMn quasicrystal, as well as two refined models obtained by filling vacant spaces. The total energies correlate almost perfectly with the reduction of the vacant space, and suggest that future modeling efforts should concentrate on increasing the coordination number of Ti sites in the glue'' regions between the large icosahedral clusters which form the backbone of the structure.

  4. Total synthesis of leucosceptroids A and B.

    PubMed

    Guo, Sheng; Liu, Jie; Ma, Dawei

    2015-01-19

    Leucosceptroids?A and B are sesterterpenoids with potent antifeedant and antifungal activities. A more efficient gram-scale total synthesis of leucosceptroid?B and the first total synthesis of leucosceptroid?A are presented. The key transformations include an aldol reaction between a substituted dihydrofuranone and an (S)-citronellal-derived aldehyde, a SmI2-mediated intramolecular ketyl-olefin radical cyclization, and final-stage alcohol oxidation. PMID:25470240

  5. Total Acquired Vulval Synechia: An Unusual Presentation

    PubMed Central

    2015-01-01

    An unusual case of Acquired Total vulval synechia due to vulvar Lichen planus is reported in an 18-year-old girl, which is an extremely rare condition. It has a potential for producing extensive scarring and narrowing of introitus resulting in dyspareunia and rarely carcinoma of vulva. Successful surgical management of total vulvar synechiae in patient suffering from Lichen Planus is being reported. PMID:26023590

  6. Total lymphoid irradiation and discordant cardiac xenografts

    SciTech Connect

    Kaplan, E.; Dresdale, A.R.; Diehl, J.T.; Katzen, N.A.; Aronovitz, M.J.; Konstam, M.A.; Payne, D.D.; Cleveland, R.J. )

    1990-01-01

    Total lymphoid irradiation can prolong concordant cardiac xenografts. The effects of total lymphoid irradiation in a discordant xenograft model (guinea pig to rat) were studied with and without adjuvant pharmacologic immunosuppression. Inbred Lewis rats were randomly allocated to one of four groups. Group 1 (n = 6) served as a control group and rats received no immunosuppression. Group 2 (n = 5) received triple-drug therapy that consisted of intraperitoneal azathioprine (2 mg/kg), cyclosporine (20 mg/kg), and methylprednisolone (1 mg/kg) for 1 week before transplantation. Group 3 animals (n = 5) received 15 Gy of total lymphoid irradiation in 12 divided doses over a 3-week period. Group 4 (n = 6) received both triple-drug therapy and total lymphoid irradiation as described for groups 2 and 3. Complement-dependent cytotoxicity assay was performed to determine if a correlation between complement-dependent cytotoxicity and rejection-free interval existed. Rejection was defined as cessation of graft pulsation and was confirmed by histologic test results. Only groups 1 and 2 showed a difference in survival (group 1, 6.9 +/- 1.0 minutes; group 2, 14.2 +/- 2.7 minutes, p = 0.02). Although total lymphoid irradiation did decrease complement-dependent cytotoxicity, linear regression revealed no correlation between complement-dependent cytotoxicity and graft survival (coefficient of correlation, 0.30). Unlike concordant cardiac xenografts, total lymphoid irradiation with or without triple-drug therapy does not prolong graft survival.

  7. EVALUATION OF THE TECHNICON BLOCK DIGESTOR SYSTEM FOR TOTAL KJELDAHL NITROGEN AND TOTAL PHOSPHORUS

    EPA Science Inventory

    Technicon's block digestor method for the simultaneous determination of total phosphorus and total Kjeldahl nitrogen has been evaluated and modified for the semi-automated determination of these constituents in surface water and domestic and industrial wastes. The Technicon diges...

  8. Ultra-low wear rates for rigid-on-rigid bearings in total hip replacements.

    PubMed

    Clarke, I C; Good, V; Williams, P; Schroeder, D; Anissian, L; Stark, A; Oonishi, H; Schuldies, J; Gustafson, G

    2000-01-01

    With the increased clinical interest in metal-on-metal and ceramic-on-ceramic total-hip replacements (THRs), the objective of this hip simulator study was to identify the relative wear ranking of three bearing systems, namely CoCr-polyethylene (M-PE), CoCr-CoCr (M-M) and ceramic-on-ceramic (C-C). Volumetric wear rates were used as the method of comparison. The seven THR groupings included one M-PE study, two M-M studies and four C-C studies. Special emphasis was given to defining the 'run-in' phase of accelerated wear that rigid-on-rigid bearings generally exhibit. The hypothesis was that characterization of the run-in and steady state wear phases would clarify not only the tribological performance in vitro but also help correlate these in vitro wear rates with the 'average' wear rates measured on retrieved implants. The implant systems were studied on multichannel hip simulators using the Paul gait cycle and bovine serum as the lubricant. With 28 mm CoCr heads, the PE (2.5 Mrad/N2) wear rates averaged 13 mm3/10(6) cycles duration. This was considered a low value compared with the clinical model of 74 mm3/year (for 28 mm heads). Our later studies established that this low laboratory value was a consequence of the serum parameters then in use. The mating CoCr heads (with PE cups) wore at the steady state rate of 0.028 mm3/10(6) cycles. The concurrently run Metasul M-M THRs wore at the steady state rate of 0.119 mm3/10(6) cycles with high-protein serum. In the second Metasul M-M study with low-protein serum, the THR run-in rate was 2.681 mm3/10(6) cycles and steady state was 0.977 mm3/10(6) cycles. At 10 years, these data would predict a 70-fold reduction in M-M wear debris compared with the clinical PE wear model. All M-M implants exhibited biphasic wear trends, with the transition point at 0.5 x 10(6) cycles between run-in and steady state phases, the latter averaging a 3-fold decrease in wear rate. White surface coatings on implants (coming from the serum solution) were a confounding factor but did not obscure the two orders of magnitude wear performance improvement for CoCr over PE cups. The liners in the alumina head-alumina cup combination wore at the steady state rate of 0.004 mm3/10(6) cycles over 14 x 10(6) cycles duration (high-protein serum). The zirconia head-alumina cup THR combination wore at 0.174 and 0.014 mm3/10(6) cycles for run-in and steady state rates respectively (low-protein serum). The zirconia head and cup THR combination wore slightly higher initially with 0.342 and 0.013 mm3/10(6) cycles for run-in and steady state rates respectively. Other wear studies have generally predicted catastrophic wear for such zirconia-ceramic combinations. It was noted that the zirconia wear trends were frequently masked by the effects of tenacious white surface coatings. It was possible that these coatings protected the zirconia surfaces somewhat in this simulator study. The experimental ceramic Crystaloy THR had the highest ceramic run-in wear at 0.681 mm3/10(6) cycles and typical 0.016 mm3/10(6) cycles for steady state. Since these implants represented the first Crystaloy THR sets made, it was likely that the surface conditions of this high-strength ceramic could be improved in the future. Overall, the ceramic THRs demonstrated three orders of magnitude wear performance improvement over PE cups. With zirconia implants, while the cup wear was sometimes measurable, head wear was seldom discernible. Therefore, we have to be cautious in interpreting such zirconia wear data. Identifying the run-in and steady state wear rates was a valuable step in processing the ceramic wear data and assessing its reliability. Thus, the M-M and C-C THRs have demonstrated two to three orders of reduction in volumetric wear in the laboratory compared with the PE wear standard, which helps to explain the excellent wear performance and minimal osteolysis seen with such implants at retrieval operations. PMID:10997055

  9. A high performance totally ordered multicast protocol

    NASA Technical Reports Server (NTRS)

    Montgomery, Todd; Whetten, Brian; Kaplan, Simon

    1995-01-01

    This paper presents the Reliable Multicast Protocol (RMP). RMP provides a totally ordered, reliable, atomic multicast service on top of an unreliable multicast datagram service such as IP Multicasting. RMP is fully and symmetrically distributed so that no site bears un undue portion of the communication load. RMP provides a wide range of guarantees, from unreliable delivery to totally ordered delivery, to K-resilient, majority resilient, and totally resilient atomic delivery. These QoS guarantees are selectable on a per packet basis. RMP provides many communication options, including virtual synchrony, a publisher/subscriber model of message delivery, an implicit naming service, mutually exclusive handlers for messages, and mutually exclusive locks. It has commonly been held that a large performance penalty must be paid in order to implement total ordering -- RMP discounts this. On SparcStation 10's on a 1250 KB/sec Ethernet, RMP provides totally ordered packet delivery to one destination at 842 KB/sec throughput and with 3.1 ms packet latency. The performance stays roughly constant independent of the number of destinations. For two or more destinations on a LAN, RMP provides higher throughput than any protocol that does not use multicast or broadcast.

  10. Prosthetic total disk replacement--can we learn from total hip replacement?

    PubMed

    Mayer, H Michael; Siepe, Christoph J

    2011-10-01

    Total lumbar disk replacement has become a routine procedure in many countries. However, discussions regarding its use are ongoing. Issues focus on patient selection, technical limitations, and avoidance or management of complications or long-term outcomes. A review of the development of this technology, since the development of the first successful implantation of a total lumbar disk prosthesis in 1984, shows an amazing analogy to the history of total hip replacement. This article is a one-to-one comparison of the evolution of total hip and total lumbar disk replacement from "skunk works" to scientific evidence. PMID:21944590

  11. Total pancreatectomy with islet autotransplantation: an overview

    PubMed Central

    Ong, Seok L; Gravante, Gianpiero; Pollard, Cristina A; Webb, M'Balu A; Illouz, Severine; Dennison, Ashley R

    2009-01-01

    Pain control is one of the most challenging aspects in the management of chronic pancreatitis. Total pancreatectomy can successfully relieve the intractable abdominal pain in these patients but will inevitably result in insulin-dependent diabetes. Islet autotransplantation aims to preserve, as far as possible, the insulin secretory function of the islet cell mass thereby reducing (or even removing) the requirement for exogenous insulin administration after a total pancreactomy. Despite the relatively small number of centres able to perform these procedures, there are important technical variations in the details of their approaches. The aim of this review is to provide details of the current surgical practice for total pancreatectomy combined with islet autotransplantation, and outline the potential advantages and disadvantages of the variations adopted in each centre. PMID:20495628

  12. KP solitons, total positivity, and cluster algebras

    PubMed Central

    Kodama, Yuji; Williams, Lauren K.

    2011-01-01

    Soliton solutions of the KP equation have been studied since 1970, when Kadomtsev and Petviashvili [Kadomtsev BB, Petviashvili VI (1970) Sov Phys Dokl 15:539541] proposed a two-dimensional nonlinear dispersive wave equation now known as the KP equation. It is well-known that the Wronskian approach to the KP equation provides a method to construct soliton solutions. The regular soliton solutions that one obtains in this way come from points of the totally nonnegative part of the Grassmannian. In this paper we explain how the theory of total positivity and cluster algebras provides a framework for understanding these soliton solutions to the KP equation. We then use this framework to give an explicit construction of certain soliton contour graphs and solve the inverse problem for soliton solutions coming from the totally positive part of the Grassmannian. PMID:21562211

  13. Total Solar Eclipse of 1999 August 11

    NASA Technical Reports Server (NTRS)

    Espenak, Fred; Anderson, Jay

    1997-01-01

    On 1999 August 11, a total eclipse of the Sun will be visible from within a narrow corridor which traverses the Eastern Hemisphere. The path of the Moon's umbral shadow begins in the Atlantic and crosses central Europe, the Middle East, and India, where it ends at sunset in the Bay of Bengal. A partial eclipse will be seen within the much broader path of the Moon's penumbral shadow, which includes northeastern North America, all of Europe, northern Africa, and the western half of Asia. Detailed predictions for this event are presented and include besselian elements, geographic coordinates of the path of totality, physical ephemeris of the umbra, topocentric limb profile corrections, local circumstances for approximately 1400 cities, maps of the eclipse path, weather prospects, the lunar limb profile, and the sky during totality. Tips and suggestions are also given on how to safely view and photograph the eclipse.

  14. Assay development status report for total cyanide

    SciTech Connect

    Simpson, B.C.; Jones, T.E.; Pool, K.H.

    1993-02-01

    A validated cyanide assay that is applicable to a variety of tank waste matrices is necessary to resolve certain waste tank safety issues and for purposes of overall waste characterization. The target for this effort is an assay with an applicable range of greater than 1,000 ppM (0.10 wt%) total cyanide and a confidence level greater than 80%. Figure 1 illustrates the operating regime of the proposed cyanide assay method. The Assay Development Status Report for Total Cyanide will summarize the past experience with cyanide analyses on-tank waste matrices and will rate the status of the analytical methods used to assay total cyanide (CN{sup {minus}} ion) in the tank waste matrices as acceptable or unacceptable. This paper will also briefly describe the current efforts for improving analytical resolution of the assays and the attempts at speciation.

  15. Total Solar Eclipse of 2008 August 01

    NASA Technical Reports Server (NTRS)

    Espenak, F.; Anderson, J.

    2007-01-01

    On 2008 August 01, a total eclipse of the Sun is visible from within a narrow corridor that traverses half the Earth. The path of the Moon's umbral shadow begins in northern Canada and extends across Greenland, the Arctic, central Russia, Mongolia, and China. A partial eclipse is seen within the much broader path of the Moon's penumbral shadow, which includes northeastern North America, most of Europe and Asia. Detailed predictions for this event are presented and include besselian elements, geographic coordinates of the path of totality, physical ephemeris of the umbra, topocentric limb profile corrections, local circumstances for 308 cities, maps of the eclipse path, weather prospects, the lunar limb profile and the sky during totality. Information on safe eclipse viewing and eclipse photography is included.

  16. Total Solar Eclipse of 2006 March 29

    NASA Technical Reports Server (NTRS)

    Espenak, F.; Anderson, J.

    2004-01-01

    On 2006 March 29, a total eclipse of the Sun will be visible from within a narrow corridor which traverses half the Earth. The path of the Moon's umbral shadow begins in Brazil and extends across the Atlantic, northern Africa, and central Asia where it ends at sunset in western Mongolia. A partial eclipse will be seen within the much broader path of the Moon's penumbral shadow, which includes the northern two thirds of Africa, Europe, and central Asia.Detailed predictions for this event are presented and include besselian elements, geographic coordinates of the path of totality, physical ephemeris of the umbra, topocentric limb profile corrections, local circumstances for approximately 350 cities, maps of the eclipse path, weather prospects, the lunar limb profile, and the sky during totality. Information on safe eclipse viewing and eclipse photography is included.

  17. Total Solar Eclipse of 2001 June 21

    NASA Technical Reports Server (NTRS)

    Espenak, Fred; Anderson, Jay

    1999-01-01

    On 2001 June 21, a total eclipse of the Sun will be visible from within a narrow corridor which traverses the Southern Hemisphere. The path of the Moon's umbral shadow begins in the South Atlantic, crosses southern Africa and Madagascar, and ends at sunset in the Indian Ocean. A partial eclipse will be seen within the much broader path of the Moon's penumbral shadow, which includes eastern South America and the southern two thirds of Africa. Detailed predictions for this event are presented and include besselian elements, geographic coordinates of the path of totality, physical ephemeris of the umbra, topocentric limb profile corrections, local circumstances for approximately 350 cities, maps of the eclipse path, weather prospects, the lunar limb profile and the sky during totality. Tips and suggestions are also given on how to safely view and photograph the eclipse.

  18. Total quality management in orthodontic practice.

    PubMed

    Atta, A E

    1999-12-01

    Quality is the buzz word for the new Millennium. Patients demand it, and we must serve it. Yet one must identify it. Quality is not imaging or public relations; it is a business process. This short article presents quality as a balance of three critical notions: core clinical competence, perceived values that our patients seek and want, and the cost of quality. Customer satisfaction is a variable that must be identified for each practice. In my practice, patients perceive quality as communication and time, be it treatment or waiting time. Time is a value and cost that must be managed effectively. Total quality management is a business function; it involves diagnosis, design, implementation, and measurement of the process, the people, and the service. Kazien is a function that reduces value services, eliminates waste, and manages time and cost in the process. Total quality management is a total commitment for continuous improvement. PMID:10587600

  19. Total Solar Eclipse of 1997 March 9

    NASA Technical Reports Server (NTRS)

    Espenak, Fred; Anderson, Jay

    1995-01-01

    A total eclipse of the Sun will be visible from Asia and the Pacific Ocean on 1997 March 9. The path of the Moon's umbral shadow begins in eastern Kazakhstan and travels through Mongolia and eastern Siberia, where it swings northward to end at sunset in the Arctic Ocean. A partial eclipse will be seen within the much broader path of the Moon's penumbral shadow, which includes eastern Asia, the northern Pacific, and the northwest corner of North America. Detailed predictions for this event are presented and include besselian elements, geographic coordinates of the path of totality, physical ephemeris of the umbra, topocentric limb profile corrections, local circumstances for 280 cities, maps of the eclipse path, weather prospects, the lunar limb profile, and the sky during totality. Tips and suggestions are also given on how to safely view and photograph the eclipse.

  20. Total Solar Eclipse of 2002 December 04

    NASA Technical Reports Server (NTRS)

    Espenak, Fred; Anderson, Jay

    2001-01-01

    On 2002 December 04, a total eclipse of the Sun will be visible from within a narrow corridor which traverses the Southern Hemisphere. The path of the Moon's umbral shadow begins in the South Atlantic, crosses southern Africa and the Indian Ocean, and ends at sunset in southern Australia. A partial eclipse will be seen within the much broader path of the Moon's penumbral shadow, which includes the southern two thirds of Africa, Antarctica, Indian Ocean and Australia. Detailed predictions for this event are presented and include besselian elements, geographic coordinates of the path of totality, physical ephemeris of the umbra, topocentric limb profile corrections, local circumstances for approximately 400 cities, maps of the eclipse path, weather prospects, the lunar limb profile and the sky during totality. Information on safe eclipse viewing and eclipse photography is included.

  1. COMPONENT VERSION IN MODULAR TOTAL HIP REVISION

    PubMed Central

    Kopec, Michael A.; Pemberton, Aaron; Milbrandt, Joseph C.; Allan, Gordon

    2009-01-01

    Morphologic changes of the proximal femur make revision total hip arthroplasty challenging. Metaphyseal retroversion and diaphyseal varus are common in this scenario. Twenty-one total hip revisions using a modular femoral prosthesis were examined by obtaining three radiographs (A/P, surgical lateral, and true lateral of the femur) to assemble CAD models for determining the range of modular component positioning. An average of femoral neck anteversion was observed. Seventeen of 21 cases (81%) had retroverted metaphyseal segments (?23.2+/?17.4) and/or varus stems (?32.1+/?13.0). Neck anteversion averaged 21.4(+/?10.0). One of 21 cases (5%) resulted in component orientation similar to a non-modular prosthesis. Modular components provide options to accommodate proximal femoral remodeling not afforded by monobloc stems in total hip revision surgery. PMID:19742077

  2. An Operational Perspective of Total Lightning Information

    NASA Technical Reports Server (NTRS)

    Nadler, David J.; Darden, Christopher B.; Stano, Geoffrey; Buechler, Dennis E.

    2009-01-01

    The close and productive collaborations between the NWS Warning and Forecast Office, the Short Term Prediction and Research Transition Center at NASA Marshall Space Flight Center and the University of Alabama in Huntsville have provided a unique opportunity for science sharing and technology transfer. One significant technology transfer that has provided immediate benefits to NWS forecast and warning operations is the use of data from the North Alabama Lightning Mapping Array. This network consists of ten VHF receivers deployed across northern Alabama and a base station located at the National Space Science and Technology Center. Preliminary investigations done at WFO Huntsville, along with other similar total lightning networks across the country, have shown distinct correlations between the time rate-of-change of total lightning and trends in intensity/severity of the parent convective cell. Since May 2003 when WFO HUN began receiving these data - in conjunction with other more traditional remotely sensed data (radar, satellite, and surface observations) -- have improved the situational awareness of the WFO staff. The use of total lightning information, either from current ground based systems or future space borne instrumentation, may substantially contribute to the NWS mission, by enhancing severe weather warning and decision-making processes. Operational use of the data has been maximized at WFO Huntsville through a process that includes forecaster training, product implementation, and post event analysis and assessments. Since receiving these data, over 50 surveys have been completed highlighting the use of total lightning information during significant events across the Tennessee Valley. In addition, around 150 specific cases of interest have been archived for collaborative post storm analysis. From these datasets, detailed trending information from radar and total lightning can be compared to corresponding damage reports. This presentation will emphasize the effective use of total lightning information in warning decision making along with best practices for implementation of new technologies into operations.

  3. Imaging Total Stations - Modular and Integrated Concepts

    NASA Astrophysics Data System (ADS)

    Hauth, Stefan; Schlüter, Martin

    2010-05-01

    Keywords: 3D-Metrology, Engineering Geodesy, Digital Image Processing Initialized in 2009, the Institute for Spatial Information and Surveying Technology i3mainz, Mainz University of Applied Sciences, forces research towards modular concepts for imaging total stations. On the one hand, this research is driven by the successful setup of high precision imaging motor theodolites in the near past, on the other hand it is pushed by the actual introduction of integrated imaging total stations to the positioning market by the manufacturers Topcon and Trimble. Modular concepts for imaging total stations are manufacturer independent to a large extent and consist of a particular combination of accessory hardware, software and algorithmic procedures. The hardware part consists mainly of an interchangeable eyepiece adapter offering opportunities for digital imaging and motorized focus control. An easy assembly and disassembly in the field is possible allowing the user to switch between the classical and the imaging use of a robotic total station. The software part primarily has to ensure hardware control, but several level of algorithmic support might be added and have to be distinguished. Algorithmic procedures allow to reach several levels of calibration concerning the geometry of the external digital camera and the total station. We deliver insight in our recent developments and quality characteristics. Both the modular and the integrated approach seem to have its individual strengths and weaknesses. Therefore we expect that both approaches might point at different target applications. Our aim is a better understanding of appropriate applications for robotic imaging total stations. First results are presented. Stefan Hauth, Martin Schlüter i3mainz - Institut für Raumbezogene Informations- und Messtechnik FH Mainz University of Applied Sciences Lucy-Hillebrand-Straße 2, 55128 Mainz, Germany

  4. Correlations between corneal and total wavefront aberrations

    NASA Astrophysics Data System (ADS)

    Mrochen, Michael; Jankov, Mirko; Bueeler, Michael; Seiler, Theo

    2002-06-01

    Purpose: Corneal topography data expressed as corneal aberrations are frequently used to report corneal laser surgery results. However, the optical image quality at the retina depends on all optical elements of the eye such as the human lens. Thus, the aim of this study was to investigate the correlations between the corneal and total wavefront aberrations and to discuss the importance of corneal aberrations for representing corneal laser surgery results. Methods: Thirty three eyes of 22 myopic subjects were measured with a corneal topography system and a Tschernig-type wavefront analyzer after the pupils were dilated to at least 6 mm in diameter. All measurements were centered with respect to the line of sight. Corneal and total wavefront aberrations were calculated up to the 6th Zernike order in the same reference plane. Results: Statistically significant correlations (p < 0.05) between the corneal and total wavefront aberrations were found for the astigmatism (C3,C5) and all 3rd Zernike order coefficients such as coma (C7,C8). No statistically significant correlations were found for all 4th to 6th order Zernike coefficients except for the 5th order horizontal coma C18 (p equals 0.003). On average, all Zernike coefficients for the corneal aberrations were found to be larger compared to Zernike coefficients for the total wavefront aberrations. Conclusions: Corneal aberrations are only of limited use for representing the optical quality of the human eye after corneal laser surgery. This is due to the lack of correlation between corneal and total wavefront aberrations in most of the higher order aberrations. Besides this, the data present in this study yield towards an aberration balancing between corneal aberrations and the optical elements within the eye that reduces the aberration from the cornea by a certain degree. Consequently, ideal customized ablations have to take both, corneal and total wavefront aberrations, into consideration.

  5. Nucleon-Nucleon Total Cross Section

    NASA Technical Reports Server (NTRS)

    Norbury, John W.

    2008-01-01

    The total proton-proton and neutron-proton cross sections currently used in the transport code HZETRN show significant disagreement with experiment in the GeV and EeV energy ranges. The GeV range is near the region of maximum cosmic ray intensity. It is therefore important to correct these cross sections, so that predictions of space radiation environments will be accurate. Parameterizations of nucleon-nucleon total cross sections are developed which are accurate over the entire energy range of the cosmic ray spectrum.

  6. Measuring Total and Germinable Spore Populations

    NASA Technical Reports Server (NTRS)

    Noell, A.C.; Yung, P.T.; Yang, W.; Lee, C.; Ponce, A.

    2011-01-01

    It has been shown that bacterial endospores can be enumerated using a microscopy based assay that images the luminescent halos from terbium ions bound to dipicolinic acid, a spore specific chemical marker released upon spore germination. Further development of the instrument has simplified it towards automation while at the same time improving image quality. Enumeration of total spore populations has also been developed allowing measurement of the percentage of viable spores in any population by comparing the germinable/culturable spores to the total. Percentage viability will allow a more quantitative comparison of the ability of spores to survive across a wide range of extreme environments.

  7. Measuring Total and Germinable Spore Populations

    NASA Astrophysics Data System (ADS)

    Noell, A. C.; Yung, P. T.; Yang, W.; Ponce, A.; Lee, C.

    2011-10-01

    It has been shown that bacterial endospores can be enumerated using a microscopy based assay that images the luminescent halos from terbium ions bound to dipicolinic acid, a spore specific chemical marker released upon spore germination. Further development of the instrument has simplified it towards automation while at the same time improving image quality. Enumeration of total spore populations has also been developed allowing measurement of the percentage of viable spores in any population by comparing the germinable/culturable spores to the total. Percentage viability will allow a more quantitative comparison of the ability of spores to survive across a wide range of extreme environments.

  8. The ?*?* total cross section in NLA BFKL

    NASA Astrophysics Data System (ADS)

    Ivanov, Dmitry Yu.; Murdaca, Beatrice; Papa, Alessandro

    2015-04-01

    We study the ?*?* total cross section in the NLA BFKL approach. We have extracted the NLO corrections to the photon impact factor from two recent papers of Balitsky and Chirilli and Chirilli and Kovchegov and used them to build several representations of the total cross section, equivalent within the NLA. We have combined these different representations with two among the most common methods for the optimization of a perturbative series, namely PMS and BLM, and compared their behavior with the energy with the only available experimental data, those from the LEP2 collider.

  9. Abel inversion using total-variation regularization

    NASA Astrophysics Data System (ADS)

    Asaki, T. J.; Chartrand, R.; Vixie, K. R.; Wohlberg, B.

    2005-12-01

    In the case of radiography of a cylindrically symmetric object, the Abel transform is useful for describing the tomographic measurement operator. The inverse of this operator is unbounded, so regularization is required for the computation of satisfactory inversions. We introduce the use of the total variation seminorm for this purpose, and prove the existence and uniqueness of solutions of the corresponding variational problem. We illustrate the effectiveness of the total-variation regularization with an example and comparison with the unregularized inverse and the H1 regularized inverse.

  10. Determination of total solutes in synfuel wastewaters

    SciTech Connect

    Wallace, J.R.; Bonomo, F.S.

    1984-03-01

    Efforts to investigate both lyophilization and the measurement of colligative properties as an indication of total solute content are described. The objective of the work described is to develop a method for measuring total dissolved material in retort wastewaters which is simple and rugged enough to be performed in a field laboratory in support of pollution control tests. The analysis should also be rapid enough to provide timely and pertinent data to the pollution control plant operator. To be of most value, the technique developed also should be applicable to other synfuel wastewaters, most of which contain similar major components as oil shale retort waters. 4 references, 1 table.

  11. Nutrition, total fluid and bladder cancer.

    PubMed

    Brinkman, Maree; Zeegers, Maurice P

    2008-09-01

    Bladder cancer is a major health concern for older males in Western populations. About 30 years ago there was a suggestion that nutrition may have a role in the aetiology of the disease. Although the literature has been accumulating since then, owing to heterogeneity between studies results have often been inconsistent and unclear. The aim of this paper was to present an updated summary of the scientific evidence on the association between nutrition, total fluid intake and bladder cancer. A search of computerized databases, PubMed, ISI, Embase and Cochrane Library, was conducted to identify all epidemiological studies published between 1966 and October 2007. The level of scientific evidence for the various nutritional factors and total fluid intake was ranked according to the number of studies reporting a statistically significant association and the existence of mechanistic evidence. The levels of association were based on a ranking of statistically significant relative risks. Fruit and yellow-orange vegetables, particularly carrots and selenium, are probably associated with a moderately reduced risk of bladder cancer. Citrus fruits and cruciferous vegetables were also identified as having a possible protective effect. Possible risk factors are salted and barbecued meat, pork, total fat, pickled vegetables, salt, soy products, spices and artificial sweeteners. No clear association could be determined for beef, eggs, processed meats and total fluid intake. In conclusion, specific fruit and vegetables may act to reduce the risk of bladder cancer. Future studies on bladder cancer should investigate the effect of food categorization, amount and gender. PMID:18815914

  12. The Total Solar Eclipse, March 1970

    ERIC Educational Resources Information Center

    Glenn, William H.

    1970-01-01

    Describes the circumstances of the total and partial solar eclipse of March 7, 1970 in certain American cities. Also discussed are (1) a classroom demonstration of the cause of solar eclipses, (2) techniques for safely observing the eclipse, and (3) what to observe during the eclipse. Bibliography. (LC)

  13. The Leica TCRA1105 Reflectorless Total Station

    SciTech Connect

    Gaudreault, F.

    2005-09-06

    This poster provides an overview of SLAC's TCRA1105 reflectorless total station for the Alignment Engineering Group. This instrument has shown itself to be very useful for planning new construction and providing quick measurements to difficult to reach or inaccessible surfaces.

  14. Mineral Analysis of Whole Grain Total Cereal

    ERIC Educational Resources Information Center

    Hooker, Paul

    2005-01-01

    The quantitative analysis of elemental iron in Whole Grain Total Cereal using visible spectroscopy is suitable for a general chemistry course for science or nonscience majors. The more extensive mineral analysis, specifically for the elements iron, calcium and zinc, is suitable for an instrumental or quantitative analysis chemistry course.

  15. How to calculate total purchase cost.

    PubMed

    Harding, M L

    1998-05-01

    Companies wanting to implement a total cost-based supplier selection process often stumble over how to include nonmonetary issues such as delivery and quality performance, lead time, services, and social policies. This article describes a process that allows a company to include any issue it deems relevant and to determine its cost factor. PMID:10178553

  16. [What's new about total knee arthroplasty].

    PubMed

    Dao Trong, Mai Lang; Helmy, Nder

    2013-10-30

    Osteoarthritis of the knee is one of the most common problems in the orthopedic practice and its surgical technique is still challenging. This Mini-Review presents patient specific cutting blocks for the implantation of a total knee arthroplasty. PMID:24169482

  17. Total energy calculations and bonding at interfaces

    SciTech Connect

    Louie, S.G.

    1984-08-01

    Some of the concepts and theoretical techniques employed in recent ab initio studies of the electronic and structural properties of surfaces and interfaces are discussed. Results of total energy calculations for the 2 x 1 reconstructed diamond (111) surface and for stacking faults in Si are reviewed. 30 refs., 8 figs.

  18. Revitalizing Space Operations through Total Quality Management

    NASA Technical Reports Server (NTRS)

    Baylis, William T.

    1995-01-01

    The purpose of this paper is to show the reader what total quality management (TQM) is and how to apply TQM in the space systems and management arena. TQM is easily understood, can be implemented in any type of business organization, and works.

  19. Total Energy Management for Minnesota Schools.

    ERIC Educational Resources Information Center

    Minnesota State Dept. of Energy, Planning and Development, St. Paul.

    Total Energy Management (TEM) is a unified, planned approach to reducing the energy use and costs of an individual school or school district. The program increases energy awareness and improves school energy efficiency through: (1) careful energy accounting; (2) changes in operations and maintenance procedures; (3) modifications in the building

  20. Total Quality Management. ERIC Digest, Number 73.

    ERIC Educational Resources Information Center

    Weaver, Tyler

    The Japanese success story has made W. Edwards Deming's Total Quality Management (TQM) theory increasingly popular among American managers, from car manufacturers to educational leaders. TQM is based on two tenets: the primacy of customer satisfaction and the necessity of tapping nontraditional sources (especially employee ideas) to institute

  1. Total main rotor isolation system analysis

    NASA Technical Reports Server (NTRS)

    Sankewitsch, V.

    1981-01-01

    Requirements, preliminary design, and verification procedures for a total main rotor isolation system at n/rev are presented. The fuselage is isolated from the vibration inducing main rotor at one frequency in all degrees of freedom by four antiresonant isolation units. Effects of parametric variations on isolation system performance are evaluated.

  2. PROCEDURE FOR ESTIMATING PERMANENT TOTAL ENCLOSURE COSTS

    EPA Science Inventory

    The paper discusses a procedure for estimating permanent total enclosure (PTE) costs. (NOTE: Industries that use add-on control devices must adequately capture emissions before delivering them to the control device. One way to capture emissions is to use PTEs, enclosures that mee...

  3. A Campus Is a Total Community.

    ERIC Educational Resources Information Center

    Hunt, Robert E.

    1979-01-01

    Described are the various components of the total college or university community and their associated environmental health and safety problems. Included are food service, insect and rodent control, multi-use athletic facilities, housing, laboratory animal facilities, laboratory biosafety, radiological health, fire protection, and emergency

  4. Total Quality Management in Libraries: A Sourcebook.

    ERIC Educational Resources Information Center

    O'Neil, Rosanna M., Comp.

    Total Quality Management (TQM) brings together the best aspects of organizational excellence by driving out fear, offering customer-driven products and services, doing it right the first time by eliminating error, and maintaining inventory control without waste. Libraries are service organizations which are constantly trying to improve service.

  5. English in a Program of Total Innovation

    ERIC Educational Resources Information Center

    Knoll, Robert E.

    1970-01-01

    Explains an experimental program designed to give the student a total look at himself and his society through literature, politics, and history; a paper presented at annual convention of National Council of Teachers of English (Washington, D. C., November 28, 1969) and published in Kansas English" (February 1970). (Editor/SW)

  6. Total Quality Management: Making Camps Successful.

    ERIC Educational Resources Information Center

    Trotter, Kathleen M.

    1995-01-01

    Total Quality Management for camps involves establishing ongoing assessment of campers' and parents' needs, marketing the capabilities of the organization, applying input of key staff members, and constantly making program improvements. This approach calls for discretionary decision making at all levels, and empowers staff to enter into the…

  7. Total Quality Management: Institutional Research Applications.

    ERIC Educational Resources Information Center

    Heverly, Mary Ann

    Total Quality Management (TQM), a technique traditionally reserved for the manufacturing sector, has recently spread to service companies, government agencies, and educational institutions. TQM places responsibility for quality problems with management rather than on the workers. A principal concept of TQM is the management of Process Variation,

  8. Applying Total Quality Management in Cooperative Extension.

    ERIC Educational Resources Information Center

    Fredendall, Lawrence D.; Lippert, Robert M.

    1995-01-01

    South Carolina's Agricultural Service Laboratory received responses from 252 of 500 farmers who currently use the soil testing service; 97% were pleased with accuracy, 89% with turnaround time, 18% thought the fee too high. Nonusers (100 of 520) were mainly dissatisfied with turnaround time. Total quality management methods were used to improve

  9. Total Synthesis of ()-Alstoscholarisine?A.

    PubMed

    Bihelovic, Filip; Ferjancic, Zorana

    2016-02-01

    The first total synthesis of the neuroactive indole alkaloid ()-alstoscholarisine?A is reported. The key step of the concise synthesis is an efficient domino sequence that was used to assemble the 2,8-diazabicyclo[3.3.1]nonane core through the formation of two C-N bonds and one C-C bond in a single step. PMID:26757206

  10. In-situ measurements of total carbon

    NASA Astrophysics Data System (ADS)

    Smythe, W.; Boryta, M.; Nelson, R.

    2009-04-01

    Quantitative assessment of the equilibration of biotic and pre-biotic materials and of the mechanisms leading to their presence in a planetary context requires knowledge of the relative concentrations of the organic species within a sample. The measurement of these relative concentrations is not practical for many remote sensing and in-situ techniques because of the large number of potential compounds having high variance in (for example) volatility, spectral response and/or molecular weight. One approach is to compare the concentration of identified materials to the total carbon and total organic carbon in a sample. The traditional two-stage approach for this measurement is acidification to convert "inorganic" carbon to CO2 and pyrolysis to convert the remaining "organic" carbon and carbon-based compounds the CO2. Measurement of the evolved CO2 provides a measure of organic and total carbon in the sample. These measurements are relatively successful in a laboratory context, but are difficult to implement robotically, particularly in challenging environments. A variety of alternative approaches for achieving total carbon measurements with acceptable accuracy are examined for feasibility of use in a field or robotic environment, with particular emphasis on soils on Mars.

  11. Total Quality Management (TQM) in Higher Education.

    ERIC Educational Resources Information Center

    Sullivan, Michael F.

    This document consists largely of paper versions of the transparencies used by the author to give his conference paper on Total Quality Management (TQM) in the college and university setting. An introduction lists a series of definitional phrases, a list of what TQM is not, and 11 fundamental principles describing what TQM is. The three major…

  12. Total Synthesis of ()-7-epi-Nemorosone

    PubMed Central

    Zhang, Qiang; Porco, John A.

    2012-01-01

    A concise total synthesis of ()-7-epi-nemorosone is reported. Our synthetic approach establishes a viable route to polycyclic polyprenylated acylphloroglucinol natural products (PPAPs) bearing a C-7 endo prenyl sidechain. Key steps include retro-aldol-vinyl cerium addition to a hydroxy adamantane core scaffold and palladium-mediated deoxygenation. PMID:22449198

  13. Total synthesis of ()-7-epi-nemorosone.

    PubMed

    Zhang, Qiang; Porco, John A

    2012-04-01

    A concise total synthesis of ()-7-epi-nemorosone is reported. Our synthetic approach establishes a viable route to polycyclic polyprenylated acylphloroglucinol natural products (PPAP's) bearing a C-7 endo prenyl side chain. Key steps include retro-aldol-vinyl cerium addition to a hydroxy adamantane core scaffold and palladium-mediated deoxygenation. PMID:22449198

  14. A Campus Is a Total Community.

    ERIC Educational Resources Information Center

    Hunt, Robert E.

    1979-01-01

    Described are the various components of the total college or university community and their associated environmental health and safety problems. Included are food service, insect and rodent control, multi-use athletic facilities, housing, laboratory animal facilities, laboratory biosafety, radiological health, fire protection, and emergency…

  15. Asymmetric Total Synthesis of (-)-Kravanhin?B.

    PubMed

    Zhong, Zhuliang; Ma, Donghui; Zhao, Gaoyuan; Li, Huilin; Xu, Dengyu; Xie, Xingang; She, Xuegong

    2015-12-01

    The first asymmetric total synthesis of kravanhin?B has been accomplished with a linear reaction sequence of 13?steps starting from (R)-(-)-carvone. The synthesis features an intramolecular aldol cyclization to construct the desired cis-fused decalin skeleton and an acid-catalyzed dehydration and olefin isomerization to install the ?-butenolide ring. PMID:26398294

  16. Total Quality Management: Implications for Higher Education.

    ERIC Educational Resources Information Center

    Hoffman, Allan M., Ed.; Julius, Daniel J., Ed.

    This book contains 19 papers describing the implementation of Total Quality Management in a variety of higher education settings. Following a Foreword by Peter Likins and a Preface by Daniel J. Julius, the chapter titles and authors are: (1) "TQM: Implications for Higher Education--A Look Back to the Future" (Allan M. Hoffman and Randall Summers);

  17. Application of Total Quality Management in Education

    ERIC Educational Resources Information Center

    Farooq, M. S.; Akhtar, M. S.; Ullah, S. Zia; Memon, R. A.

    2007-01-01

    The purpose of the paper is to analyzing thoughts of the modern management paradigm "Total Quality Management" (TQM), and its application in the field of education. The basic theme of TQM is participatory approach to address the question(s) of quality in business aswell as in the field of education. Reviewing fresh literature from the internet

  18. Coordinating Council. Ninth Meeting: Total Quality Management

    NASA Technical Reports Server (NTRS)

    1992-01-01

    This report summarizes the 9th meeting of the STI Coordinating Council. The council listened to the speakers' understanding of Total Quality Management (TQM) principles and heard stories of successful applications of these principles. Definitions of quality stated were focused on customer satisfaction. Reports presented by the speakers are also included.

  19. Asymmetric total synthesis of ent-cyclooroidin

    PubMed Central

    Mukherjee, Sabuj; Sivappa, Rasapalli; Yousufuddin, Muhammed; Lovely, Carl J.

    2010-01-01

    An enantiospecific total synthesis of the pyrrole-imidazole natural product cyclooroidin from histidine is described. The key N1-C9 bond is constructed through an intramolecular SN2-type of reaction of a chloro ester. Subsequent imidazole C2-azidation at the 2-position, pyrrole bromination, azide reduction and deprotection leads to the completion of the synthesis. PMID:20929213

  20. Total Quality Management: Implications for Higher Education.

    ERIC Educational Resources Information Center

    Hoffman, Allan M., Ed.; Julius, Daniel J., Ed.

    This book contains 19 papers describing the implementation of Total Quality Management in a variety of higher education settings. Following a Foreword by Peter Likins and a Preface by Daniel J. Julius, the chapter titles and authors are: (1) "TQM: Implications for Higher Education--A Look Back to the Future" (Allan M. Hoffman and Randall Summers);…

  1. Applying Total Quality Management in Cooperative Extension.

    ERIC Educational Resources Information Center

    Fredendall, Lawrence D.; Lippert, Robert M.

    1995-01-01

    South Carolina's Agricultural Service Laboratory received responses from 252 of 500 farmers who currently use the soil testing service; 97% were pleased with accuracy, 89% with turnaround time, 18% thought the fee too high. Nonusers (100 of 520) were mainly dissatisfied with turnaround time. Total quality management methods were used to improve…

  2. Applying Total Quality Management to Business Education.

    ERIC Educational Resources Information Center

    Brown, Daniel J.; Koenig, Harold F.

    1993-01-01

    Responses from 390 business school alumni (60%) show that students want educators to consider their opinions about their overall educational experience and what happens after graduation. A total quality management approach can help discover customer/student needs, establish a focus on improvement, and implement a process orientation. (SK)

  3. Total Quality Management: Implications for Educational Assessment.

    ERIC Educational Resources Information Center

    Rankin, Stuart C.

    1992-01-01

    Deming's "System of Profound Knowledge" is even more fundamental than his 14-principle system transformation guide and is based on 4 elements: systems theory, statistical variation, a theory of knowledge, and psychology. Management should revamp total system processes so that quality of product is continually improved. Implications for educational

  4. Total Quality Management: The Emperor's Tailor.

    ERIC Educational Resources Information Center

    Alexander, Gary C.; Keeler, Carolyn M.

    Conversations among educators, business leaders, legislators, and educational reformers have generated support for the application of Total Quality Management (TQM) to education. This paper considers whether TQM is indeed the solution to education's problems. After a brief explanation of TQM theory, the paper is organized around four broad issues…

  5. Strainrange partitioning: A total strain range version

    NASA Technical Reports Server (NTRS)

    Halford, G. R.; Saltsman, J. F.

    1983-01-01

    Procedures are presented for expressing the Strainrange Partitioning (SRP) method for creep fatigue life prediction in terms of total strain range. Inelastic and elastic strain-range - life relations are summed to give total strain-range - life relations. The life components due to inelastic strains are dealt with using conventional SRP procedures while the life components due to elastic strains are expressed as families of time-dependent terms for each type of SRP cycle. Cyclic constitutive material behavior plays an important role in establishing the elastic strain-range - life relations as well as the partitioning of the inelastic strains. To apply the approach, however, it is not necessary to have to determine the magnitude of the inelastic strain range. The total strain SRP approach is evaluated and verified using two nickel base superalloys, AF2-1DA and Rene 95. Excellent agreement is demonstrated between observed and predicted cyclic lifetimes with 70 to 80 percent of the predicted lives falling within factors of two of the observed lives. The total strain-range SRP approach should be of considerable practical value to designers who are faced with creep-fatigue problems for which the inelastic strains cannot be calculated with sufficient accuracy to make reliable life predictions by the conventional inelastic strain range SRP approach.

  6. Total main rotor isolation system analysis

    NASA Technical Reports Server (NTRS)

    Halwes, D. R.

    1981-01-01

    The requirements for a preliminary design study and verification procedure for a total main rotor isolation system at n/rev are established. The system is developed and analyzed, and predesign drawings are created for an isolation system that achieves over 95 percent isolation of all six degrees of freedom.

  7. Production Function Geometry with "Knightian" Total Product

    ERIC Educational Resources Information Center

    Truett, Dale B.; Truett, Lila J.

    2007-01-01

    Authors of principles and price theory textbooks generally illustrate short-run production using a total product curve that displays first increasing and then diminishing marginal returns to employment of the variable input(s). Although it seems reasonable that a temporary range of increasing returns to variable inputs will likely occur as

  8. The total momentum of quantum fluids

    NASA Astrophysics Data System (ADS)

    St?, Andrs

    2015-08-01

    The probability distribution of the total momentum P is studied in N-particle interacting homogeneous quantum systems at positive temperatures. Using Galilean invariance we prove that in one dimension, the asymptotic distribution of P / ?{ N } is normal at all temperatures and densities, and in two dimensions, the tail distribution of P / ?{ N } is normal. We introduce the notion of the density matrix reduced to the center of mass and show that its eigenvalues are N times the probabilities of the different eigenvalues of P. A series of results is presented for the limit of sequences of positive definite atomic probability measures, relevant for the probability distribution of both the single-particle and the total momentum. The P = 0 ensemble is shown to be equivalent to the canonical ensemble. Through some conjectures we associate the properties of the asymptotic distribution of the total momentum with the characteristics of fluid, solid, and superfluid phases. Our main suggestion is that in interacting quantum systems above one dimension, in infinite space, the total momentum is finite with a nonzero probability at all temperatures and densities. In solids, this probability is 1, and in a crystal, it is distributed on a lattice. Since it is less than 1 in two dimensions, we conclude that a 2D system is always in a fluid phase, so if the hexatic phase existed classically, it would be destroyed by quantum fluctuations. For a superfluid, we conjecture that the total momentum is zero with a nonzero probability and otherwise its distribution is continuous. We define a macroscopic wave function based on the density matrix reduced to the center of mass. We discuss how dissipation can give rise to a critical velocity, predict the temperature dependence of the latter, and argue that Landau's criterion cannot explain superfluidity and its breakdown at positive temperatures. We also comment on the relation between superfluidity and Bose-Einstein condensation.

  9. Early Predictors of Hypocalcemia After Total Thyroidectomy

    PubMed Central

    Noureldine, Salem I.; Genther, Dane J.; Lopez, Michael; Agrawal, Nishant; Tufano, Ralph P.

    2015-01-01

    IMPORTANCE Postoperative hypocalcemia is common after total thyroidectomy, and perioperative monitoring of serum calcium levels is arguably the primary reason for overnight hospitalization. Confidently predicting which patients will not develop significant hypocalcemia may allow for a safe earlier discharge. OBJECTIVE To examine associations of patient characteristics with hypocalcemia, duration of hospitalization, and postoperative intact parathyroid hormone (IPTH) level after total thyroidectomy. DESIGN, SETTING, AND PARTICIPANTS Retrospective study of consecutive patients who underwent total thyroidectomy by a single high-volume surgeon between February 1, 2010, and November 30, 2012. Postoperative serum 25-hydroxyvitamin D (vitamin D), calcium, and IPTH levels were tested within 6 to 8 hours after surgery. Mild hypocalcemia was defined as any postoperative serum calcium level of less than 8.4 to 8.0 mg/dL. Significant hypocalcemia was defined as any postoperative serum calcium level of less than 8.0 mg/dL or the development of hypocalcemia-related symptoms. INTERVENTIONS Total thyroidectomy. MAIN OUTCOMES AND MEASURES Associations of patient demographic and clinical characteristics and laboratory values with postoperative mild and significant hypocalcemia were examined using univariate analysis, and independent predictors of hypocalcemia, duration of hospitalization, and IPTH level were determined using multivariate analysis. RESULTS Overall, 304 total thyroidectomies were performed. Mild and significant hypocalcemia occurred in 68 (22.4%) and 91 (29.9%) patients, respectively, of which the majority were female (P = .003). The development of significant hypocalcemia was associated with postoperative IPTH level (P < .001). On multivariate analysis, males had a decreased risk of developing mild (odds ratio, 0.37 [95% CI, 0.160.85]) and significant (odds ratio, 0.57 [95% CI, 0.090.78]) hypocalcemia. Every 10-pg/mL increase in postoperative IPTH level predicted a 43% decreased risk of significant hypocalcemia (P < .001) and an 18% decreased risk of hospitalization beyond 24 hours (P = .03). Presence of malignant neoplasm carried a 27% risk of mild hypocalcemia (P = .02). There was a progressively increasing risk of lower IPTH levels for each parathyroid gland inadvertently resected or autotransplanted. Male sex and African American race were independently predictive of higher IPTH levels. CONCLUSIONS AND RELEVANCE Low postoperative IPTH level, female sex, and presence of malignant neoplasm are all significant, independent predictors of hypocalcemia after total thyroidectomy. Clinicians should consider these variables when deciding how to best manage or prevent postoperative hypocalcemia. PMID:25321339

  10. Generalized Higher Degree Total Variation (HDTV) Regularization

    PubMed Central

    Hu, Yue; Ongie, Greg; Ramani, Sathish; Jacob, Mathews

    2015-01-01

    We introduce a family of novel image regularization penalties called generalized higher degree total variation (HDTV). These penalties further extend our previously introduced HDTV penalties, which generalize the popular total variation (TV) penalty to incorporate higher degree image derivatives. We show that many of the proposed second degree extensions of TV are special cases or are closely approximated by a generalized HDTV penalty. Additionally, we propose a novel fast alternating minimization algorithm for solving image recovery problems with HDTV and generalized HDTV regularization. The new algorithm enjoys a ten-fold speed up compared to the iteratively reweighted majorize minimize algorithm proposed in a previous work. Numerical experiments on 3D magnetic resonance images and 3D microscopy images show that HDTV and generalized HDTV improve the image quality significantly compared with TV. PMID:24710832

  11. Total synthesis of palau'amine.

    PubMed

    Namba, Kosuke; Takeuchi, Kohei; Kaihara, Yukari; Oda, Masataka; Nakayama, Akira; Nakayama, Atsushi; Yoshida, Masahiro; Tanino, Keiji

    2015-01-01

    Palau'amine has received a great deal of attention in the past two decades as an attractive synthetic target by virtue of its intriguing molecular architecture and significant immunosuppressive activity. Here we report the total synthesis of palau'amine characterized by the construction of an ABDE tetracyclic ring core including a trans-bicylo[3.3.0]octane skeleton at a middle stage of total synthesis. The ABDE tetracyclic ring core is constructed by a cascade reaction of a cleavage of the N-N bond, including simultaneous formation of imine, the addition of amide anion to the resulting imine (D-ring formation) and the condensation of pyrrole with methyl ester (B-ring formation) in a single step. The synthetic palau'amine is confirmed to exhibit excellent immunosuppressive activity. The present synthetic route has the potential to help elucidate a pharmacophore as well as the mechanistic details of immunosuppressive activity. PMID:26530707

  12. Total synthesis of palau'amine

    PubMed Central

    Namba, Kosuke; Takeuchi, Kohei; Kaihara, Yukari; Oda, Masataka; Nakayama, Akira; Nakayama, Atsushi; Yoshida, Masahiro; Tanino, Keiji

    2015-01-01

    Palau'amine has received a great deal of attention in the past two decades as an attractive synthetic target by virtue of its intriguing molecular architecture and significant immunosuppressive activity. Here we report the total synthesis of palau'amine characterized by the construction of an ABDE tetracyclic ring core including a trans-bicylo[3.3.0]octane skeleton at a middle stage of total synthesis. The ABDE tetracyclic ring core is constructed by a cascade reaction of a cleavage of the N–N bond, including simultaneous formation of imine, the addition of amide anion to the resulting imine (D-ring formation) and the condensation of pyrrole with methyl ester (B-ring formation) in a single step. The synthetic palau'amine is confirmed to exhibit excellent immunosuppressive activity. The present synthetic route has the potential to help elucidate a pharmacophore as well as the mechanistic details of immunosuppressive activity. PMID:26530707

  13. Total positive curvature of circular DNA

    NASA Astrophysics Data System (ADS)

    Bohr, Jakob; Olsen, Kasper W.

    2013-11-01

    The properties of double-stranded DNA and other chiral molecules depend on the local geometry, i.e., on curvature and torsion, yet the paths of closed chain molecules are globally restricted by topology. When both of these characteristics are to be incorporated in the description of circular chain molecules, e.g., plasmids, it is shown to have implications for the total positive curvature integral. For small circular micro-DNAs it follows as a consequence of Fenchel's inequality that there must exist a minimum length for the circular plasmids to be double stranded. It also follows that all circular micro-DNAs longer than the minimum length must be concave, a result that is consistent with typical atomic force microscopy images of plasmids. Predictions for the total positive curvature of circular micro-DNAs are given as a function of length, and comparisons with circular DNAs from the literature are presented.

  14. Solar Total Energy Project Shenandoah, Georgia

    SciTech Connect

    King, J.W.; Geurts, G.F.

    1983-06-01

    The Solar Total Energy Project (STEP) at Shenandoah, Georgia is the world's largest industrial application of solar cogeneration. It is a cooperative effort between the U. S. Department of Energy (DOE) and the Georgia Power Company to further America's search for alternative sources of energy. It is an outgrowth of research started in 1972 by Sandia National Laboratories for the U. S. Energy Research and Development Administration. The objective of the Shenandoah project is to evaluate a solar total energy system that provides electrical power, process steam, and air conditioning for a knitwear factory operated by Bleyle of America, Inc. Solar energy will displace a large part of the electricity and fossil fuels normally used to run the factory and produce the clothing.

  15. Fast total focusing method for ultrasonic imaging

    NASA Astrophysics Data System (ADS)

    Carcreff, Ewen; Dao, Gavin; Braconnier, Dominique

    2016-02-01

    Synthetic aperture focusing technique (SAFT) and total focusing method (TFM) have become popular tools in the field of ultrasonic non destructive testing. In particular, they are employed for detection and characterization of flaws. From data acquired with a transducer array, those techniques aim at reconstructing an image of the inspected object from coherent summations. In this paper, we make a comparison between the standard technique and a migration approach. Using experimental data, we show that the developed approach is faster and offers a better signal to noise ratio than the standard total focusing method. Moreover, the migration is particularly effective for near-surface imaging where standard methods used to fail. On the other hand, the migration approach is only adapted to layered objects whereas the standard technique can fit complex geometries. The methods are tested on homogeneous pieces containing artificial flaws such as side drilled holes.

  16. [Bearing selection in total hip arthroplasty].

    PubMed

    Sonntag, R; Reinders, J; Mller, U; Kretzer, J P

    2015-12-01

    Different bearing materials are available in total hip arthroplasty and it's the surgeon who has the choice between hard-on-soft, hard-on-hard and alternative materials. Ideally, the material selection should rely on evidence-based data regarding the wear performance, the incidence of revision surgery and other potential bearing-associated risk factors for the corresponding combinations of materials in the individual patient. While there are high-quality studies available for some materials, adequate data is lacking for other materials. Therefore, the current article aims to provide bearing selection criteria for the surgeon and to review the current literature regarding different combinations of bearing materials in total hip arthroplasty. PMID:26367145

  17. A Modern Approach to Total Wellbeing

    NASA Astrophysics Data System (ADS)

    Hadzic, Maja; Chen, Meifania; Brouwer, Rick; Dillon, Tharam

    The events of the last decades have impacted our lives and our health significantly. We expected that the technology boom will improve our lives. While this may be true in a specific context, generally speaking our societies are suffering from moral decays, terrorism fears, wars, financial crisis and unpredictable acts of nature that are increasing in frequency and in intensity. The complex nature of the world we live is impacting our health and wellbeing considerably. Our health is not only determined by our physical health but is the end product of the interplay of the physical, mental, emotional, financial, relational and spiritual events of a lifetime. In this paper we develop a framework that will help us define and measure total wellbeing of individuals in our volatile societies. This framework will help us better understand the complex nature of total wellbeing and develop effective prevention and intervention strategies.

  18. Outcomes of total versus subtotal abdominal hysterectomy.

    PubMed

    Asnafi, N; Basirat, Z; Hajian-Tilaki, K O

    2010-02-01

    There is still controversy about the best technique for hysterectomy to reduce postoperative adverse effects. This randomized clinical study in Babol, Islamic Republic of Iran, compared some clinical complications and sexual functioning following subtotal (SAH) and total abdominal hysterectomy (TAH). A total of 150 women (50 allocated to SAH and 100 to TAH) were followed up at 6 months postoperatively. Length of hospitalization was 4.40 (SD 1.90) days after SAH and 4.48 (SD 1.67) days after TAH. Haemoglobin level, postoperative fever, symptoms of dyspareunia and frequency of sexual intercourse were not significantly different between the 2 groups of women. SAH did not show any significant benefits over TAH. PMID:20799571

  19. Fractionated total body irradiation for metastatic neuroblastoma

    SciTech Connect

    Kun, L.E.; Casper, J.T.; Kline, R.W.; Piaskowski, V.D.

    1981-11-01

    Twelve patients over one year old with neuroblastoma (NBL) metastatic to bone and bone marrow entered a study of adjuvant low-dose, fractionated total body irradiation (TBI). Six children who achieved a ''complete clinical response'' following chemotherapy (cyclophosphamide and adriamycin) and surgical resection of the abdominal primary received TBI (10 rad/fraction to totals of 100-120 rad/10-12 fx/12-25 days). Two children received concurrent local irradiation for residual abdominal tumor. The intervals from cessation of chemotherapy to documented progression ranged from 2-16 months, not substatially different from patients receiving similar chemotherapy and surgery without TBI. Three additional children with progressive NBL received similar TBI (80-120 rad/8-12 fx) without objective response.

  20. Total synthesis of all ()-Agelastatin alkaloids

    PubMed Central

    Siegel, Dustin S.; Han, Sunkyu

    2010-01-01

    The pyrrole-imidazole family of marine alkaloids, derived from linear clathrodin-like precursors, constitutes a diverse array of structurally complex natural products. The bioactive agelastatins are members of this family that possess a tetracyclic molecular framework incorporating C4C8 and C7N12 bond connectivities. We provide a hypothesis for the formation of the unique agelastatin architecture that maximally exploits the intrinsic chemistry of plausible biosynthetic precursors. We report the concise enantioselective total syntheses of all known agelastatin alkaloids including the first total syntheses of agelastatins C, D, E, and F. Our gram-scale chemical synthesis of agelastatin A was inspired by our hypothesis for the biogenesis of the cyclopentane C-ring and required the development of new transformations including an imidazolone-forming annulation reaction and a carbohydroxylative trapping of imidazolones. PMID:21218186

  1. Total laparoscopic reversal of Hartmann's procedure.

    PubMed

    Masoni, Luigi; Mari, Francesco Saverio; Nigri, Giuseppe; Favi, Francesco; Pindozzi, Fioralba; Dall'Oglio, Anna; Pancaldi, Alessandra; Brescia, Antonio

    2013-01-01

    Hartmann's procedure is still performed in those cases in which colorectal anastomosis might be unsafe. Reversal of Hartmann's procedure (HR) is considered a major surgical procedure with a high morbidity (55 to 60%) and mortality rate (0 to 4%). To decrease these rates, laparoscopic Hartmann's reversal procedure was successfully experienced. We report our totally laparoscopic Hartmann's reversal technique. Between 2004 and 2010 we performed 27 HRs with a totally laparoscopic approach. The efficacy and safety of this technique were demonstrated evaluating the operative data, postoperative complications, and the outcome of the patients. There were no open conversions or major intraoperative complications. Anastomotic leaking occurred in one patient requiring an ileostomy; one patient needed a blood transfusion and one had a nosocomial pneumonia. The mean postoperative hospitalization was 5.7 days. Laparoscopic HR is a feasible and safe procedure and can be considered a valid alternative to open HR. PMID:23317614

  2. Frustrated total internal reflection acoustic field sensor

    DOEpatents

    Kallman, Jeffrey S.

    2000-01-01

    A frustrated total internal reflection acoustic field sensor which allows the acquisition of the acoustic field over an entire plane, all at once. The sensor finds use in acoustic holography and acoustic diffraction tomography. For example, the sensor may be produced by a transparent plate with transparent support members tall enough to support one or more flexible membranes at an appropriate height for frustrated total internal reflection to occur. An acoustic wave causes the membrane to deflect away from its quiescent position and thus changes the amount of light that tunnels through the gap formed by the support members and into the membrane, and so changes the amount of light reflected by the membrane. The sensor(s) is illuminated by a uniform tight field, and the reflection from the sensor yields acoustic wave amplitude and phase information which can be picked up electronically or otherwise.

  3. Gravitation experiments during the total solar eclipse

    SciTech Connect

    Kuusela, T.; Jaeykkae, J.; Kiukas, J.; Multamaeki, T.; Ropo, M.; Vilja, I.

    2006-12-15

    The variations of the apparent vertical direction of the gravity field were measured with horizontal gravimeters acting as tilt meters during the total solar eclipse in Turkey in March 29, 2006. Three separated locations within the path of totality were chosen for observations, two spaced apart along the center line, and one off the center line. No anomaly was observed at the furthest location from the center line. Aperiodic oscillations in tilt were recorded at the two locations on the center line. These may be related to the eclipse phenomenon. The average tilt amplitude deviation during the eclipse over all locations and in all directions was 150 nrad, which can be regarded as a mean upper limit for the eclipse related changes in the tilt.

  4. Total body irradiation in chronic myeloid leukemia

    SciTech Connect

    Advani, S.H.; Dinshaw, K.A.; Nair, C.N.; Ramakrishnan, G.

    1983-04-01

    Total body irradiation (TBI), given as 10 rad daily for five days a week for a total dose of 150 rad has been used in an attempt to control the chronic phase of chronic myeloid leukemia (CML). Thirteen patients with CML received fractionated TBI leading to rapid and good control of WBC count without any adverse reaction. The chronic phase of CML could also be controlled with TBI, even in three patients who were resistant to busulfan. Following TBI, WBC count remained under control for a period of 32 weeks as compared to 40 weeks following vusulfan alone. Repeat TBI was also well tolerated with good response. It appears that TBI is an effective and safe therapy for controlling the chronic phase of CML.

  5. Increasing productivity through Total Reuse Management (TRM)

    NASA Technical Reports Server (NTRS)

    Schuler, M. P.

    1991-01-01

    Total Reuse Management (TRM) is a new concept currently being promoted by the NASA Langley Software Engineering and Ada Lab (SEAL). It uses concepts similar to those promoted in Total Quality Management (TQM). Both technical and management personnel are continually encouraged to think in terms of reuse. Reuse is not something that is aimed for after a product is completed, but rather it is built into the product from inception through development. Lowering software development costs, reducing risk, and increasing code reliability are the more prominent goals of TRM. Procedures and methods used to adopt and apply TRM are described. Reuse is frequently thought of as only being applicable to code. However, reuse can apply to all products and all phases of the software life cycle. These products include management and quality assurance plans, designs, and testing procedures. Specific examples of successfully reused products are given and future goals are discussed.

  6. Metallosis in a total knee arthroplasty

    PubMed Central

    Vivegananthan, Bhairavi; Shah, Rohi; Karuppiah, A S; Karuppiah, S V

    2014-01-01

    A 70-year-old woman presented with right knee pain and a ‘grinding’ sensation 6 months after a total knee replacement for osteoarthritis. Clinical examination revealed a valgus deformity, patellofemoral crepitus and a reduced knee flexion. Radiographs revealed distinctive findings including the ‘bubble sign’, ‘cloud sign’ and the ‘metal line sign’, which are diagnostic of metallosis.Metallosis is an uncommon complication of total joint replacements, where bone and periprosthetic soft tissues are infiltrated by metallic debris from wearing of the prostheses. This usually occurs in high-wear joints such as hips and knees. Treatment for patients diagnosed with metallosis is synovectomy and a revision surgery. Our patient underwent revision surgery 5 years after her initial surgery. PMID:24642179

  7. Kelvin waves in total column ozone

    NASA Technical Reports Server (NTRS)

    Ziemke, J. R.; Stanford, J. L.

    1993-01-01

    Tropical Kelvin waves have been observed previously in ozone mixing ratio data from the SBUV (Solar Backscatter Ultraviolet) and LIMS (Limb Infrared Monitor of the Stratosphere) instruments on board the Nimbus-7 satellite. Kelvin wave features in total column ozone, using version 6 data from the Total Ozone Mapping Spectrometer (TOMS) instrument (also on board Nimbus-7) are investigated. Results show eastward-propagating zonal waves 1-2 with periods approximately 5-15 days, amplitudes approximately 3-5 DU, and latitudinal symmetry typical of Kelvin waves. A simplified model calculation suggests that the primary source for the perturbations is slow Kelvin waves in the lower-to-middle stratosphere. Maximum Kelvin wave signatures occur in conjunction with westward lower-to-middle stratospheric equatorial zonal winds (a quasi-biennial oscillation (QBO) wind modulation effect).

  8. Concise total synthesis of ()-actinophyllic acid

    PubMed Central

    Granger, Brett A.; Jewett, Ivan T.; Butler, Jeffrey D.; Martin, Stephen F.

    2014-01-01

    A concise total synthesis of the complex indole alkaloid ()-actinophyllic acid was accomplished by a sequence of reactions requiring only 10 steps from readily-available, known starting materials. The approach featured a Lewis acid-catalyzed cascade of reactions involving stabilized carbocations that delivered the tetracyclic core of the natural product in a single chemical operation. Optimal conversion of this key intermediate into ()-actinophyllic acid required judicious selection of a protecting group strategy. PMID:24882888

  9. Enantioselective Total Synthesis of (-)-Hosieine?A.

    PubMed

    Ouyang, Jie; Yan, Rui; Mi, Xianwei; Hong, Ran

    2015-09-01

    The first total synthesis of (-)-hosieine?A was accomplished and features an unprecedented nitroso-ene cyclization to construct the 2-azabicyclo[3.2.1]octane ring system. Phosphine-enabled stereoselective bromohydrination provided interesting mechanistic insights into the anti-Markovnikov process. Also noteworthy is the retention of stereochemistry at C9 in the facile radical debromination initiated by Et3 B/air. PMID:26212928

  10. Candida Endocarditis Complicating Glucose Total Intravenous Nutrition

    PubMed Central

    Gazzaniga, A. B.; Mir-Sepasi, M. H.; Jefferies, M. R.; Yeo, M. T.

    1974-01-01

    A case of Candida albicans endocarditis is reported. The endocarditis occurred in a patient with a chronic illness who received intermittent glucose total intravenous nutrition for approximately 10 weeks. The patient developed severe aortic insufficiency with his valvular endocarditis and required emergency aortic valve replacement. Aggressive surgery and medical treatment appear to be the treatment of choice for these critically ill patients. ImagesFig. 2.Fig. 3.Fig. 4. PMID:4209025

  11. Total Hip Joint Replacement Biotelemetry System

    NASA Technical Reports Server (NTRS)

    Boreham, J. F.; Postal, R. B.; Luntz, R. A.

    1981-01-01

    The development of a biotelemetry system that is hermetically sealed within a total hip replacement implant is reported. The telemetry system transmits six channels of stress data to reconstruct the major forces acting on the neck of the prosthesis and uses an induction power coupling technique to eliminate the need for internal batteries. The activities associated with the telemetry microminiaturization, data recovery console, hardware fabrications, power induction systems, electrical and mechanical testing and hermetic sealing test results are discussed.

  12. Nonlinear identification of the total baroreflex arc.

    PubMed

    Moslehpour, Mohsen; Kawada, Toru; Sunagawa, Kenji; Sugimachi, Masaru; Mukkamala, Ramakrishna

    2015-12-15

    The total baroreflex arc [the open-loop system relating carotid sinus pressure (CSP) to arterial pressure (AP)] is known to exhibit nonlinear behaviors. However, few studies have quantitatively characterized its nonlinear dynamics. The aim of this study was to develop a nonlinear model of the sympathetically mediated total arc without assuming any model form. Normal rats were studied under anesthesia. The vagal and aortic depressor nerves were sectioned, the carotid sinus regions were isolated and attached to a servo-controlled piston pump, and the AP and sympathetic nerve activity (SNA) were measured. CSP was perturbed using a Gaussian white noise signal. A second-order Volterra model was developed by applying nonparametric identification to the measurements. The second-order kernel was mainly diagonal, but the diagonal differed in shape from the first-order kernel. Hence, a reduced second-order model was similarly developed comprising a linear dynamic system in parallel with a squaring system in cascade with a slower linear dynamic system. This "Uryson" model predicted AP changes 12% better (P < 0.01) than a linear model in response to new Gaussian white noise CSP. The model also predicted nonlinear behaviors, including thresholding and mean responses to CSP changes about the mean. Models of the neural arc (the system relating CSP to SNA) and peripheral arc (the system relating SNA to AP) were likewise developed and tested. However, these models of subsystems of the total arc showed approximately linear behaviors. In conclusion, the validated nonlinear model of the total arc revealed that the system takes on an Uryson structure. PMID:26354845

  13. NASA total quality management 1989 accomplishments report

    NASA Technical Reports Server (NTRS)

    1990-01-01

    Described here are the accomplishments of NASA as a result of the use of Total Quality Management (TQM). The principles in practice which led to these process refinements are important cultural elements to any organization's productivity and quality efforts. The categories of TQM discussed here are top management leadership and support, strategic planning, focus on the customer, employee training and recognition, employee empowerment and teamwork, measurement and analysis, and quality assurance.

  14. Total synthesis of hapalindoles J and U.

    PubMed

    Rafferty, Ryan J; Williams, Robert M

    2012-01-01

    The total synthesis of D,L-hapalindoles J and U has been accomplished. Hapalindole J was prepared in 11% overall yield over 11 synthetic steps and hapalindole U was prepared in 25% overall yield over 13 synthetic steps from commercially available materials. The route employs a novel silyl ether-based strategy for accessing the 6:5:6:6 ring system of the hapalindoles rapidly and in good yields. PMID:22126131

  15. Measurement of total organic concentration in water

    NASA Technical Reports Server (NTRS)

    Winkler, E.

    1978-01-01

    Instrument for determining total organic concentration in water uses no corrosive reagents or gases. Instead continuous ultraviolet photolysis process converts organic compounds to carbon dioxide (CO2). CO2 electrode is used to measure CO2 content. Only reagent necessary is oxygen, generated in situ by electrolyzing some water. In addition to application in aerospace industry, system has potential uses in pollution monitoring and in laboratory analyses.

  16. Enantioselective Formal Total Synthesis of (+)-Aspergillide C

    PubMed Central

    Panarese, Joseph D.; Waters, Stephen P.

    2009-01-01

    An enantioselective formal total synthesis of the cytotoxic macrolide (+)-aspergillide C has been accomplished from (S)-(?)-glyceraldehyde acetonide and the DanishefskyKitahara diene. Strategic transformations include a hetero DielsAlder reaction, Ferrier-type addition, and palladium-catalyzed oxidative lactonization to set key stereocenters within the dihydropyran core, followed by fragment coupling via (E)-selective JuliaKocienski olefination. PMID:19817392

  17. Total synthesis of neolaulimalide and isolaulimalide.

    PubMed

    Gollner, Andreas; Mulzer, Johann

    2008-10-16

    The first total syntheses of the potential antitumoral leads neolaulimalide (2) and isolaulimalide (3) have been achieved. Key steps in our convergent, fully stereocontrolled route are a Yamaguchi macrolactonization, a Julia-Lythgoe-Kocienski olefination, a Kulinkovich reaction, and a cyclopropyl-allyl rearrangement to install the exo-methylene group. Overall, we synthesized 2 in 21 linear steps (3% yield) and 3 in 24 steps (2% yield). PMID:18816129

  18. Concise total synthesis of (+)-aspergillide B.

    PubMed

    Liu, Jian; Xu, Ke; He, Jinmei; Zhang, Ling; Pan, Xinfu; She, Xuegong

    2009-07-17

    An efficient total synthesis of (+)-aspergillide B has been achieved, which features the C-glycosylation reaction for constructing the 2,6-trans-substituted pyran core, a highly effective four-step sequence without purification to produce the key intermediate 13 and an advantegous E-selective Julia-Kocienski olefination on a highly elaborate substrate. The synthesis confirmed the revised structure of aspergillide B by Uenishi. PMID:19485348

  19. Enantioselective formal total synthesis of (+)-aspergillide C.

    PubMed

    Panarese, Joseph D; Waters, Stephen P

    2009-11-01

    An enantioselective formal total synthesis of the cytotoxic macrolide (+)-aspergillide C has been accomplished from (S)-(-)-glyceraldehyde acetonide and the Danishefsky-Kitahara diene. Strategic transformations include a hetero Diels-Alder reaction, Ferrier-type addition, and palladium-catalyzed oxidative lactonization to set key stereocenters within the dihydropyran core, followed by fragment coupling via (E)-selective Julia-Kocienski olefination. PMID:19817392

  20. NASA total quality management 1990 accomplishments report

    NASA Technical Reports Server (NTRS)

    1991-01-01

    NASA's efforts in Total Quality Management are based on continuous improvement and serve as a foundation for NASA's present and future endeavors. Given here are numerous examples of quality strategies that have proven effective and efficient in a time when cost reduction is critical. These accomplishment benefit our Agency and help to achieve our primary goal, keeping American in the forefront of the aerospace industry.

  1. Total Synthesis of (+)-Rubriflordilactone?A.

    PubMed

    Goh, Shermin S; Chaubet, Guilhem; Gockel, Birgit; Cordonnier, Marie-Caroline A; Baars, Hannah; Phillips, Andrew W; Anderson, Edward A

    2015-10-19

    Two enantioselective total syntheses of the nortriterpenoid natural product rubriflordilactone?A are described, which use palladium- or cobalt-catalyzed cyclizations to form the CDE rings, and converge on a late-stage synthetic intermediate. These key processes are set up through the convergent coupling of a common diyne component with appropriate AB-ring aldehydes, a strategy that sets the stage for the synthetic exploration of other members of this family of natural products. PMID:26337920

  2. Total Synthesis of Hapalindoles J and U

    PubMed Central

    Rafferty, Ryan J.; Williams, Robert M.

    2011-01-01

    The total synthesis of D,L-hapalindoles J and U has been accomplished. Hapalindole J was prepared in 11% overall yield over eleven synthetic steps and hapalindole U was prepared in 25% overall yield over thirteen synthetic steps from commercially available materials. The route employs a novel silyl ether-based strategy for accessing the 6:5:6:6 ring system of the hapalindoles rapidly and in good yields. PMID:22126131

  3. Total synthesis of (+)-antroquinonol and (+)-antroquinonol D.

    PubMed

    Sulake, Rohidas S; Chen, Chinpiao

    2015-03-01

    The first total synthesis of (+)-antroquinonol and (+)-antroquinonol D, two structurally unique quinonols with a sesquiterpene side chain, is described. The route features an iridium-catalyzed olefin isomerization-Claisen rearrangement reaction (ICR), lactonization, and Grubbs olefin metathesis. The requisite α,β-unsaturation was achieved via the selenylation/oxidation protocol and elimination of β-methoxy group to provide two natural products from a common intermediate. PMID:25679542

  4. Assessing Operational Total Lightning Visualization Products

    NASA Technical Reports Server (NTRS)

    Stano, Geoffrey T.; Darden, Christopher B.; Nadler, David J.

    2010-01-01

    In May 2003, NASA's Short-term Prediction Research and Transition (SPoRT) program successfully provided total lightning data from the North Alabama Lightning Mapping Array (NALMA) to the National Weather Service (NWS) office in Huntsville, Alabama. The major accomplishment was providing the observations in real-time to the NWS in the native Advanced Weather Interactive Processing System (AWIPS) decision support system. Within days, the NALMA data were used to issue a tornado warning initiating seven years of ongoing support to the NWS' severe weather and situational awareness operations. With this success, SPoRT now provides real-time NALMA data to five forecast offices as well as working to transition data from total lightning networks at Kennedy Space Center and the White Sands Missile Range to the surrounding NWS offices. The only NALMA product that has been transitioned to SPoRT's partner NWS offices is the source density product, available at a 2 km resolution in 2 min intervals. However, discussions with users of total lightning data from other networks have shown that other products are available, ranging from spatial and temporal variations of the source density product to the creation of a flash extent density. SPoRT and the Huntsville, Alabama NWS are evaluating the utility of these variations as this has not been addressed since the initial transition in 2003. This preliminary analysis will focus on what products will best support the operational warning decision process. Data from 19 April 2009 are analyzed. On this day, severe thunderstorms formed ahead of an approaching cold front. Widespread severe weather was observed, primarily south of the Tennessee River with multiple, weak tornadoes, numerous severe hail reports, and wind. This preliminary analysis is the first step in evaluation which product(s) are best suited for operations. The ultimate goal is selecting a single product for use with all total lightning networks to streamline training and science sharing.

  5. Economics of a total maintenance coatings program

    SciTech Connect

    Poncio, S.; Adkison, P. )

    1994-08-01

    Coating costs are escalating due to increased awareness of the environment and safety and health issues. Owners can reduce the overall cost of maintenance painting projects through the implementation of a total quality program. This program should encompass project pre-planning, evaluation of safety and quality assurance programs, and analysis of employee absenteeism and turnover. The information presented is a case history of one utility's experience managing a maintenance painting program during a five-year period.

  6. Total synthesis of panicein A2

    PubMed Central

    Yeung, Lili; Pilkington, Lisa I; Cadelis, Melissa M; Copp, Brent R

    2015-01-01

    Summary The first total synthesis of the unusual aromatic sesquiterpene panicein A2 is reported and the structure of the natural product has been confirmed. When tested by the NCI against a range of human cancer cell lines, it was found that panicein A2 exhibits very little antiproliferative activity at 10 ?M an observation that is at odds with the earlier report that stated panicein A2 exhibits in vitro cytotoxicity against a number of tumour cell lines. PMID:26664619

  7. Bioinspired total synthesis of gymnothelignan N.

    PubMed

    Li, Huilin; Zhang, Yuanyuan; Xie, Xingang; Ma, Haichen; Zhao, Changgui; Zhao, Gaoyuan; She, Xuegong

    2014-09-01

    Bioinspired total synthesis of gymnothelignan N was accomplished in 13 steps and 6.7% overall yield. The synthesis features a syn Evans aldol reaction, an intramolecular hydrogenative dehydration reaction, and a phenol oxidative dearomatization/Friedel-Crafts reaction, which provides a new plausible biosynthetic pathway for the gymnothelignans and other symbiotic members. Meanwhile, another tetrahydrofuran-type lignan beilschmin A was also synthesized. PMID:25103476

  8. [Total ankle arthroplasty in valgus ankle osteoarthritis].

    PubMed

    Valderrabano, V; Frigg, A; Leumann, A; Horisberger, M

    2011-11-01

    Ankle osteoarthritis (OA) is often associated with deformities. Valgus OA is less frequent than varus OA and causes of valgus OA include medial ligament instability, flat foot and posttraumatic situations, e.g. fractures of the fibula or lateral tibial plafond. The importance of the mechanical axis is generally accepted in orthopedic surgery. In cases of implantation of total ankle replacements the normal biomechanics need to be restored in order to have a correct and pain-free functioning total ankle replacement both in the short and long-term. The two most important criteria are (1) an anterior tibio-talar angle of about 90 and (2) a neutral hindfoot position. The hindfoot position is measured with the hindfoot alignment view according to Saltzman. In this view, healthy feet are in neutral or minimal varus position of 1-2 and not in a valgus position as generally assumed. The following operative steps are performed depending on the degree and localization of the valgus deformity: (1) total ankle replacement, (2) supramalleolar or (3) inframalleolar osteotomy/arthrodesis, (4) medial ligament repair, (5) fibula osteotomy and (6) syndesmotic reconstruction. PMID:22009496

  9. Modular tibial augmentations in total knee arthroplasty.

    PubMed

    Fehring, T K; Peindl, R D; Humble, R S; Harrow, M E; Frick, S L

    1996-06-01

    Proximal tibial bony deficiencies are not uncommon in primary and revision total knee arthroplasty. Modular tibial augmentations were introduced to address these deficiencies. Alterations in strain distribution as a result of medial wedge and block augmentations were evaluated for a modular total knee arthroplasty system in 6 fresh frozen anatomic specimen tibias. Full-field strain patterns were examined using photoelastic coating methods, and high strain regions were evaluated using strain gage rosette techniques. The total knee arthroplasty installations were tested in static physiologic axial and torsional load configurations. The relative effects of sequential wedge and block augmentations compared with the nonaugmented case were statistically analyzed. There were no overall statistical differences in the 3 treatments in terms of maximal (principal) strains. A secondary analysis that evaluated specific location and load pattern combinations established several minor statistical differences along with insights into the manner in which each construct loads the proximal tibia. Although metal wedge augmentation commonly is used, block augmentation seems to be an appropriate alternative from a strain distribution standpoint in cases in which the block geometry better approximates the bony defect. PMID:8641065

  10. [Total temporomandibular joint replacement with alloplastic prosthesis].

    PubMed

    Garca-Huerta, Marco Antonio; Romero-Flores, Jovita; Mena-Gmez, Eddy

    2012-01-01

    Three total temporomandibular joint (TMJ) replacement surgeries were performed on two patients with TMJ ankylosis using W. Lorenz system. The first surgery was performed on a female patient with osseous ankylosis who had no mandibular movement since she was 18 months old. The second surgery was on a patient with fibrous ankylosis who had an interincisive opening distance of 12 mm. Her condition was the result of a three year old subcondylar fracture which didn't receive any treatment. The first patient had total replacement of both TMJs, while the other just one TMJ. The follow up until today has been of eight months with an interincisive opening of 29 mm in the first patient and 34 mm in the other. There has not been any mandibular deviation during opening, nor postoperative pain in both cases. Facial nerve affection was not permanent in both patients. For all of this, we can conclude that total TMJ replacement is an effective treatment with stable results in patients with TMJ ankylosis. PMID:23234748

  11. Total quality management -- Remedial actions planning program

    SciTech Connect

    Petty, J.L.; Horne, T.E.

    1989-01-01

    This paper describes the management approach being taken within the Hazardous Waste Remedial Actions Program (HAZWRAP) Support Contractor Office (SCO) to ensure quality of services in a highly competitive waste management environment. An overview is presented of the contractor support role assigned to Martin Marietta Energy Systems, Inc., by the Department of Energy (DOE) national program for managing hazardous waste. The HAZWRAP SCO mission, organizational structure, and major programs are outlined, with emphasis on waste management planning for the DOE Work for Others (WFO) Program. The HAZWRAP SCO provides waste management technical support, via interagency agreements between DOE and various Department of Defense (DOD) agencies for DOD sponsors planning remedial response actions. The remainder of the paper focuses on how the concept of Total Quality Management is applied to the HAZWRAP Remedial Actions Planning (RAP) Program. The management challenge is to achieve quality on a ''system'' basis where all functional elements of program management synergistically contribute to the total quality of the effort. The quality assurance (QA) program requirements applied to the RAP Program and its subcontractors are discussed. The application of management principles in the areas of program management, procurement, and QA to achieve total quality is presented. 3 refs.

  12. Climate Change and Tropical Total Lightning

    NASA Technical Reports Server (NTRS)

    Albrecht, R.; Petersen, W.; Buechler, D.; Goodman, S.; Blakeslee, R.; Christian, H.

    2009-01-01

    While global warming is regarded as a fact by many in the scientific community, its future impact remains a challenge to be determined and measured. The International Panel on Climate Change (IPCC) assessment report (IPCC, 2007) shows inconclusive answers on global rainfall trends and general agreement on a future drier climate with increased global warming. The relationship between temperature, humidity and convection is not linear and is strongly dependent on regional scale features, such as topography and land cover. Furthermore, the relationship between convective lightning production (thunderstorms) and temperature is even more complicated, being subjected to the cloud dynamics and microphysics. Total lightning (intracloud and cloud-to-ground) monitoring is a relatively new field of observation. Global and tropical total lightning began to be more extensively measured by satellites in the mid 90s. In this scope, the Lightning Imaging Sensor (LIS) onboard of the Tropical Rainfall Measurement Mission (TRMM) has been operational for over 11 years. Here we address total lightning trends observed by LIS from 1998 to 2008 in different temporal (annual and seasonal) and spatial (large and regional) scales. The observed 11-year trends are then associate to different predicted/hypothesized climate change scenarios.

  13. Climate change and tropical total lightning

    NASA Astrophysics Data System (ADS)

    Albrecht, R.; Petersen, W. A.; Buechler, D. E.; Goodman, S. J.; Christian, H.

    2009-12-01

    While global warming is regarded as a fact by many in the scientific community, its future impact remains a challenge to be determined and measured. The International Panel on Climate Change (IPCC) assessment report (IPCC, 2007) shows inconclusive answers on global rainfall trends and general agreement on a future drier climate with increased global warming. The relationship between temperature, humidity and convection is not linear and is strongly dependent on regional scale features, such as topography and land cover. Furthermore, the relationship between convective lightning production (thunderstorms) and temperature is even more complicated, being subjected to the cloud dynamics and microphysics. Total lightning (intracloud and cloud-to-ground) monitoring is a relatively new field of observation. Global and tropical total lightning began to be more extensively measured by satellites in the mid 90s. In this scope, the Lightning Imaging Sensor (LIS) onboard of the Tropical Rainfall Measurement Mission (TRMM) has been operational for over 11 years. Here we address total lightning trends observed by LIS from 1998 to 2008 in different temporal (annual and seasonal) and spatial (large and regional) scales. The observed 11-year trends are then associate to different predicted/hypothesized climate change scenarios.

  14. The Error in Total Error Reduction

    PubMed Central

    Witnauer, James E.; Urcelay, Gonzalo P.; Miller, Ralph R.

    2013-01-01

    Most models of human and animal learning assume that learning is proportional to the discrepancy between a delivered outcome and the outcome predicted by all cues present during that trial (i.e., total error across a stimulus compound). This total error reduction (TER) view has been implemented in connectionist and artificial neural network models to describe the conditions under which weights between units change. Electrophysiological work has revealed that the activity of dopamine neurons is correlated with the total error signal in models of reward learning. Similar neural mechanisms presumably support fear conditioning, human contingency learning, and other types of learning. Using a computational modelling approach, we compared several TER models of associative learning to an alternative model that rejects the TER assumption in favor of local error reduction (LER), which assumes that learning about each cue is proportional to the discrepancy between the delivered outcome and the outcome predicted by that specific cue on that trial. The LER model provided a better fit to the reviewed data than the TER models. Given the superiority of the LER model with the present data sets, acceptance of TER should be tempered. PMID:23891930

  15. Observation of the total solar eclipsis. L'observation des eclipses totales solaires

    SciTech Connect

    Koutchmy, S.

    1987-03-01

    A brief historical account of the solar-total-eclipses events is presented to show their importance, including their use for the scientific analysis of the solar corona, since 1848. The main parameters and a schema of the eclipses are given. Several examples of investigations performed during a solar total eclipse are discussed.

  16. 38 CFR 3.340 - Total and permanent total ratings and unemployability.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 38 Pensions, Bonuses, and Veterans' Relief 1 2013-07-01 2013-07-01 false Total and permanent total ratings and unemployability. 3.340 Section 3.340 Pensions, Bonuses, and Veterans' Relief DEPARTMENT OF VETERANS AFFAIRS ADJUDICATION Pension, Compensation, and Dependency and Indemnity Compensation Ratings and Evaluations; Service Connection ...

  17. Fluorogenic membrane overlays to enumerate total coliforms, Escherichia coli, and total Vibrionaceae in shellfish and seawater

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Three assays were developed to enumerate total coliforms, Escherichia coli, and total Vibrionaceae in shellfish and other foods and in seawater and other environmental samples. Assays involve membrane overlays of overnight colonies on non-selective agar plates to detect ß-glucuronidase and lysyl am...

  18. [Simultaneous determination of total flavone and total saponin in Gynostemma pentaphyllum by signal multiplier spectrophotometry].

    PubMed

    Hui, Rui-Hua; Hou, Dong-Yan; Li, Tie-Chun; Liu, Xiao-Yuan

    2006-09-01

    Important chemical constituents analysis for the total flavone and total saponin in Gynostemma pentaphyllum is described. The colour reactions of flavones and saponines with vanillin-perchloric acid in acetic acid produced the good absorptions at 451 and 547 nm, but the absorption peaks too overlapped to be determined simultaneously. A new method for the total flavone and the total saponin in Gynostemma pentaphyllum to be determined by signal multiplier spectrophotometry simultaneously without any preliminary separation was proposed. For quantitative analysis, the rutinum as a standard of the total flavone and the ginsenoside Rb1 as standard of the total saponin were applied. The experiment results showed that the regression equations of concentration and deltaA were obtained: deltaAflavone = 0.0133+4.417 0Cflavone, relation coefficient rflavone = 0.9994, and the total flavone concentrations were in 0-0. 16 microg x mI(-1) with deltaA obeying linear relation; deltaAsaporin = 2.775 5Csaponin -0.8881 x 10(-2), relation coefficient rsaponin = 0.9991, and the total saponin concentrations were in 0-0.30 microg x mL(-1) with deltaA obeying linear relation respectively. The recovery ratio was 104.0%-113.0% and 86.8%-94.6% respectively. The RSDflavone was less than 0.58% (n = 9) and RSDsaponin was less than 0. 35% (n=9) respectively. The proposed method is simple, rapid accurate and feasible. PMID:17112063

  19. The 2012 Total Eclipse Expeditions in Queensland

    NASA Astrophysics Data System (ADS)

    Pasachoff, Jay M.; Babcock, B. A.; Lu, M.; Dantowitz, R.; Lucas, R.; Seiradakis, J. H.; Voulgaris, A.; Gaintatzis, P.; Steele, A.; Sterling, A. C.; Rusin, V.; Saniga, M.

    2013-07-01

    A total eclipse swept across Queensland and other sites in northeastern Australia on the early morning of 14 November 2012, local time. We mounted equipment to observe coronal images and spectra during the approximately 2 minutes of totality, the former for comparison with spacecraft images and to fill in the doughnut of imaging not well covered with space coronagraphs. Matching weather statistics, viewing was spotty, and our best observations were from a last-minute inland site on the Tablelands, with some observations from a helicopter at 9000 feet altitude over our original viewing site at Miallo. Only glimpses of the corona were visible at our Port Douglas and Trinity Beach, Cairns, locations, with totality obscured from our sites at Newell and Miallo, though some holes in the clouds provided coronal views from Palm Cove and elsewhere along the coast. Preliminary analysis of the spectra again shows Fe XIV stronger than Fe X, as in 2010 but not earlier, a sign of solar maximum, as was the coronal shape. An intriguing CME is discernible in the SE. Acknowledgments: We thank Terry Cuttle, Aram Friedman, Michael Kentrianakis, and Nicholas Weber for assistance and collaboration in Australia and Wendy Carlos for image processing. Our expedition was supported in part by NSF grant AGS-1047726 from Solar Terrestrial Research of the Atmospheric and Geospace Sciences Division, and by the Rob Spring Fund and Science Center funds at Williams College. ML was also supported in part by a Grant-In-Aid of Research from the National Academy of Sciences, administered by Sigma Xi, The Scientific Research Society (Grant ID: G20120315159311). VR and MS acknowledge support from projects VEGA 2/0003/13 and NGS-3139-12 of the National Geographic Society. We are grateful to K. Shiota (Japan) for kindly providing us with some of his 2012 eclipse coronal images.

  20. Total Synthesis of ()- and (?)-Actinophyllic Acid

    PubMed Central

    Martin, Connor L.; Overman, Larry E.; Rohde, Jason M.

    2010-01-01

    Development of efficient sequences for the total syntheses of ()-actinophyllic acid (rac-1) and (?)-actinophyllic acid (1) are described. The central step in these syntheses is the aza-Cope/Mannich reaction, which constructs the previously unknown hexacyclic ring system of actinophyllic acid in one step from much simpler tetracyclic precursors. The tetracyclic hexahydro-1,5-methano-1H-azocino[4,3-b]indole ketone rac-37 is assembled from o-nitrophenylacetic acid in four steps, with oxidative cyclization of a dienolate derivative of tricyclic precursor rac-35 being the central step. In the first-generation synthesis, this intermediate is transformed in two steps to homoallyl amine rac-43, whose formaldiminium derivative undergoes efficient aza-Cope/Mannich reaction to give pentacyclic ketone rac-44. In four additional steps, this intermediate is advanced to ()-actinophyllic acid. The synthesis is streamlined by elaborating ketone rac-37 to ?-hydroxyester intermediate rac-53, which is directly transformed to ()-actinophyllic acid upon exposure to HCl and paraformaldehyde. This concise second-generation total synthesis of ()-actinophyllic acid is realized in 22% overall yield from commercially available di-tert-butylmalonate and o-nitrophenylacetic acid by a sequence that proceeds by way of only six isolated intermediates. The first enantioselective total synthesis of (?)-actinophyllic acid (1) is accomplished by this direct sequence from tricyclic keto malonate (S)-35. Catalytic enantioselective reduction of ?,?-unsaturated ketone 66 is the key step in the preparation of intermediate (S)-35 from the commercially available Boc-amino acid 65. Discussed also is the possibility that the aza-Cope/Mannich reaction might be involved in the biosynthesis of (?)-actinophyllic acid. PMID:20218696

  1. Mesh Excision: Is Total Mesh Excision Necessary?

    PubMed

    Wolff, Gillian F; Winters, J Christian; Krlin, Ryan M

    2016-04-01

    Nearly 29 % of women will undergo a secondary, repeat operation for pelvic organ prolapse (POP) symptom recurrence following a primary repair, as reported by Abbott et al. (Am J Obstet Gynecol 210:163.e1-163.e1, 2014). In efforts to decrease the rates of failure, graft materials have been utilized to augment transvaginal repairs. Following the success of using polypropylene mesh (PPM) for stress urinary incontinence (SUI), the use of PPM in the transvaginal repair of POP increased. However, in recent years, significant concerns have been raised about the safety of PPM mesh. Complications, some specific to mesh, such as exposures, erosion, dyspareunia, and pelvic pain, have been reported with increased frequency. In the current literature, there is not substantive evidence to suggest that PPM has intrinsic properties that warrant total mesh removal in the absence of complications. There are a number of complications that can occur after transvaginal mesh placement that do warrant surgical intervention after failure of conservative therapy. In aggregate, there are no high-quality controlled studies that clearly demonstrate that total mesh removal is consistently more likely to achieve pain reduction. In the cases of obstruction and erosion, it seems clear that definitive removal of the offending mesh is associated with resolution of symptoms in the majority of cases and reasonable practice. There are a number of complications that can occur with removal of mesh, and patients should be informed of this as they formulate a choice of treatment. We will review these considerations as we examine the clinical question of whether total versus partial removal of mesh is necessary for the resolution of complications following transvaginal mesh placement. PMID:26905696

  2. Alumina versus polyethylene in total knee arthroplasty.

    PubMed

    Oonishi, H; Aono, M; Murata, N; Kushitani, S

    1992-09-01

    The cementless alumina total knee prosthesis, which uses alumina in the portions coming in contact with the bone and a combination of alumina and ultra-high molecular-weight polyethylene (UHMWPE) in the sliding portions, is referred to as a total condylar. Alumina total knee arthroplasty was performed on 137 patients, including 103 rheumatoid arthritis (RA) and 34 osteoarthrosis (OA) patients, from January 1982 to February 1985. The follow-up period was seven years 11 months and four years ten months, respectively. At follow-up evaluation, 108 patients were available for clinical and roentgenographic examinations, amounting to a 79% follow-up rate. At follow-up examination, 67 joints (62%) were completely pain free and 28 joints (26%) caused slight pain on bearing weight. Walking ability was recovered moderately in RA and markedly in OA. In RA, 14 of 84 knees were cemented and one knee was treated with loosening. Of 72 cementless implantations, 55 sustained displacing distally and one sustained loosening in the tibia, whereas 31 sustained displacing proximally and six sustained loosening in the femur. In OA, 21 cementless knees had 17 displacings in the tibia, and ten displacings and two loosenings in the femur. Scanning electron microscopy (SEM) observation of the UHMWPE surface in tibial plates revealed smoothing and burnishing. Alumina is far superior to metal for the sliding part, although it is not always best for the portion in contact with the bone. To resolve these problems, for cementless fixation, anchoring portions of Ti alloy and alumina implants were covered with beads and coated with hydroxyapatite. For cement fixation, "the interface bioactive bone cement technique" interposing hydroxyapatite granules between bone and cement was performed. PMID:1516334

  3. Enantioselective Total Synthesis of (?)-Acylfulvene and (?)-Irofulven

    PubMed Central

    Siegel, Dustin S.; Piizzi, Grazia; Piersanti, Giovanni; Movassaghi, Mohammad

    2009-01-01

    We report our full account of the enantioselective total synthesis of (?)-acylfulvene (1) and (?)-irofulven (2), which features metathesis reactions for the rapid assembly of the molecular framework of these antitumor agents. We discuss (1) the application of an Evans Cu-catalyzed aldol addition reaction using a strained cyclopropyl ketenethioacetal, (2) an efficient enyne ring-closing metathesis (EYRCM) cascade reaction in a challenging setting, (3) the reagent IPNBSH for a late stage reductive allylic transposition reaction, and (4) the final RCM/dehydrogenation sequence for the formation of (?)-acylfulvene (1) and (?)-irofulven (2). PMID:19938810

  4. Total-variation regularization with bound constraints

    SciTech Connect

    Chartrand, Rick; Wohlberg, Brendt

    2009-01-01

    We present a new algorithm for bound-constrained total-variation (TV) regularization that in comparison with its predecessors is simple, fast, and flexible. We use a splitting approach to decouple TV minimization from enforcing the constraints. Consequently, existing TV solvers can be employed with minimal alteration. This also makes the approach straightforward to generalize to any situation where TV can be applied. We consider deblurring of images with Gaussian or salt-and-pepper noise, as well as Abel inversion of radiographs with Poisson noise. We incorporate previous iterative reweighting algorithms to solve the TV portion.

  5. Total quality management approach improves medication replacement.

    PubMed

    Anderson, L K

    1994-07-01

    Total quality management (TQM) is based on understanding customer needs, improving key processes that affect customer satisfaction, and creating cross-functional teams to resolve process problems. This article describes application of TQM principles and problem-solving processes to improve one OR's medication exchange system. The problem was excessive monthly pharmacy medication replacement costs. The goal was to reduce the monthly medication replacement costs by 50%. Within four months, monthly medication replacement charges decreased from $656 to $302, and by one year, monthly charges decreased to $160. The new process had fewer steps, fewer staff members involved, and fewer delays in medication replacement. PMID:8085806

  6. Solar Total Energy Project summary description

    NASA Astrophysics Data System (ADS)

    Hunke, R. W.; Leonard, J. A.

    1983-03-01

    The Solar Total Energy Project (STEP) at Shenandoah, GA is described. A summary description of the energy system, its location, and the project site are presented. The system is further described including design criteria and requirements, performance criteria, and operating requirements. The major subsystems of the STEP - the solar collection subsystem (SCS), the power conversion subsystem, the thermal utilization subsystem, the control and instrumentation subsystem, and the electrical subsystem are described, including their major components. Specific features of the control and instrumentation provisions for the system and subsystem operational modes are also described and the costs of construction presented.

  7. Solar total energy project summary description

    SciTech Connect

    Hunke, R.W.; Leonard, J.A.

    1983-03-01

    The Solar Total Energy Project (STEP) at Shenandoah, GA is described. A summary description of the energy system, its location, and the project site are presented. The system is further described including design criteria and requirements, performance criteria, and operating requirements. The major subsystems of the STEP--the Solar Collection Subsystem (SCS), the Power Conversion Subsystem (PCS), the Thermal Utilization Subsystem (TUS), the Control and Instrumentation Subsystem (CAIS), and the Electrical Subsystem (ES)--are described, including their major components. Specific features of the control and instrumentation provisions for the system and subsystem operational modes are also described and the costs of construction presented.

  8. [Total rhegmatogenous retinal detachment - late postoperative complication].

    PubMed

    Stefaniu, I; Ionic?, N; Ni??, N; Ni?ulescu, C; Chiril?, D; Zamfir, C

    2000-01-01

    This paper presents the case of a pacient operated for organized hemoftalmus after central retinal vein thrombosis (total vitrectomy) and whom five days after surgery a macular hole was observed and internal indendation with gas was performed. Postoperative evolution was good. Two months after surgery the pacient returns with cvasitotal regmatogen retinal detachment. The possible causes in bringing about of the retinal detachment in this case will be discussed as well as the factors that condition the success in posterior pole surgery. PMID:11392836

  9. Biomimetic total synthesis of santalin?Y.

    PubMed

    Strych, Sebastian; Journot, Guillaume; Pemberton, Ryan P; Wang, Selina C; Tantillo, Dean J; Trauner, Dirk

    2015-04-20

    A biomimetic total synthesis of santalin?Y, a structurally complex but racemic natural product, is described. The key step is proposed to be a (3+2)?cycloaddition of a benzylstyrene to a "vinylogous oxidopyrylium", which is followed by an intramolecular Friedel-Crafts reaction. This cascade generates the unique oxafenestrane framework of the target molecule and sets its five stereocenters in one operation. Our work provides rapid access to santalin?Y and clarifies its biosynthetic relationship with other colorants isolated from red sandalwood. PMID:25858797

  10. Total Mercury in Six Antarctic Notothenioid Fishes.

    PubMed

    Wintle, Nathan J P; Sleadd, Isaac M; Gundersen, Deke T; Kohl, Kristina; Buckley, Bradley A

    2015-11-01

    We analyzed white muscle samples from six species of Antarctic fish (suborder Notothenioidei) collected in 2011 from McMurdo Sound, Ross Sea, Antarctica, to assess levels of total mercury (THg). Gymnodraco acuticeps and Trematomus bernacchii exhibited the highest concentrations of THg followed by Trematomus pennellii, Trematomus nicolai, Trematomus newnesi and Pagothenia borchgrevinki, (71.3, 53.932.1, 45.827.3, 37.218.6, 35.723.6, and 21.92.8ng/g wet weight, respectively). The results from this study suggest that THg has the potential to bioaccumulate from various marine Antarctic ecosystems into biota. PMID:26155962

  11. Total synthesis of diterpenoid steenkrotin A.

    PubMed

    Pan, Saiyong; Xuan, Jun; Gao, Beiling; Zhu, An; Ding, Hanfeng

    2015-06-01

    A concise and diastereoselective total synthesis of the diterpenoid ()-steenkrotin?A is described for the first time. The strategy mainly features three key ring formations: 1)?a rhodium-catalyzed O-H bond insertion followed by an intramolecular carbonyl-ene reaction to build up the tetrahydrofuran subunit; 2)?sequential SmI2 -mediated Ueno-Stork and ketyl-olefin cyclizations to construct the [5,7] spirobicyclic skeleton; and 3)?an intramolecular aldol condensation/vinylogous retro-aldol/aldol sequence to form the final six-membered ring with inversion of the relative configuration at the C7 position. PMID:25891977

  12. Cervical total disk replacement: complications and avoidance.

    PubMed

    Salari, Behnam; McAfee, Paul C

    2012-01-01

    Anterior cervical diskectomy and fusion for neurologic deficits, radicular arm pain, and neck pain refractory to conservative management are successful. The approach and procedure were first described in 1955 and have become the anterior cervical standard of care for orthopedic surgeons and neurosurgeons. Advancements and innovations have addressed disease processes of the cervical spine with motion-preserving technology. The possibility of obtaining anterior cervical decompression while maintaining adjacent segment motion led to the advent of cervical total disk replacement. The Food and Drug Administration has approved 3 cervical devices with other investigational device exemption trials under way. PMID:22082633

  13. Enantioselective Total Synthesis of Secalonic Acid E.

    PubMed

    Ganapathy, Dhandapani; Reiner, Johannes R; Lffler, Lorenz E; Ma, Ling; Gnanaprakasam, Boopathy; Nieptter, Benedikt; Koehne, Ingo; Tietze, Lutz F

    2015-11-16

    The first enantioselective synthesis of a secalonic acid containing a dimeric tetrahydroxanthenone skeleton is described, using a Wacker-type cyclization of a methoxyphenolic compound to form a chiral chroman with a quaternary carbon stereogenic center with >99% ee. Further steps are a Sharpless dihydroxylation and a Dieckmann condensation to give a tetrahydroxanthenone. A late-stage one-pot palladium-catalyzed Suzuki-dimerization reaction leads to the 2,2'-biphenol linkage to complete the enantioselective total synthesis of secalonic acid E in 18?steps with 8% overall yield. PMID:26447631

  14. An Enantioselective Total Synthesis of (-)-Isoschizogamine.

    PubMed

    Xu, Zhengren; Bao, Xu; Wang, Qian; Zhu, Jieping

    2015-12-01

    A concise enantioselective total synthesis of (-)-isoschizogamine, a complex bridged polycyclic monoterpene indole alkaloid, was accomplished. N-Alkylation of an enantio-enriched imine with an alkyl iodide afforded an iminium salt, which, upon heating by microwave irradiation in the presence of pivalic acid, was converted into the hexacyclic structure of natural product by a complex but ordered domino sequence. The one-pot process leading to the formation of one C?C bond and three C?N bonds created three rings and three contiguous stereogenic centers with complete control of both the relative and absolute stereochemistry. PMID:26473745

  15. Enantioselective Total Synthesis of (+)-Lyngbyabellin M

    PubMed Central

    Pirovani, Rodrigo V.; Brito, Gilmar A.; Barcelos, Rosimeire C.; Pilli, Ronaldo A.

    2015-01-01

    Lyngbyabellin M is a non-ribosomal peptide synthetase/polyketide synthase derived metabolite isolated from the cyanobacterium M. bouillonii displaying thiazole rings and a distinct chlorinated octanoic acid chain. Its absolute configuration was proposed based on the comparison of its spectroscopic data with those of other representatives of this family of marine natural products, as well as degradation and derivatization studies. Here the first total synthesis of (+)-lyngbyabellin M is described based on the coupling of three key intermediates: two chiral thiazole moieties and an anti hydroxycarboxylic acid prepared stereoselectively via a boron enolate mediated aldol reaction directed by Masamune’s chiral auxiliary. PMID:26023838

  16. Prosthetic design considerations in total shoulder arthroplasty.

    PubMed

    Flatow, E L

    1995-10-01

    Total shoulder replacements should, as far as possible, be designed after normal anatomy. A small mismatch in curvature between the humeral head and glenoid surfaces may reduce edge loading when the humerus translates on the glenoid, but may increase contact stresses caused by point loading. Modularity increases sizing options but decreases head size for a given soft-tissue space and introduces the risk of component dissociation. Releases and soft-tissue balancing at surgery, and rehabilitation afterwards, are more important than the type of glenohumeral prosthesis implanted. PMID:10172731

  17. Total cost of operating an information engine

    NASA Astrophysics Data System (ADS)

    Um, Jaegon; Hinrichsen, Haye; Kwon, Chulan; Park, Hyunggyu

    2015-03-01

    We study a two-level system controlled in a discrete feedback loop, modeling both the system and the controller in terms of stochastic Markov processes. We find that the extracted work, which is known to be bounded from above by the mutual information acquired during measurement, has to be compensated by an additional energy supply during the measurement process itself, which is bounded by the mutual information from below. Our results confirm that the total cost to operate an information engine is in full agreement with the conventional second law of thermodynamics. We also consider the efficiency of the information engine in the finite-time case.

  18. [Bilateral vocal cord paresis after total thyroidectomy].

    PubMed

    Dralle, H; Neu, J; Musholt, T J; Nies, C

    2016-01-01

    A 66-year-old female patient complained of hoarseness and dyspnea under exertion following total thyroidectomy. Due to a faulty operating technique both nerves to the vocal cords were damaged. From the operation report it emerged that the dissection was carried out by protecting the border lamellae but the recurrent laryngeal nerve could not be found on both sides. This article presents the external expert opinion, the decision of the arbitration board and the assessment of the case by two specialist physicians. PMID:26683653

  19. Security Systems Consideration: A Total Security Approach

    NASA Astrophysics Data System (ADS)

    Margariti, S. V.; Meletiou, G.; Stergiou, E.; Vasiliadis, D. C.; Rizos, G. E.

    2007-12-01

    The "safety" problem for protection systems is to determine in a given situation whether a subject can acquire a particular right to an object. Security and audit operation face the process of securing the application on computing and network environment; however, storage security has been somewhat overlooked due to other security solutions. This paper identifies issues for data security, threats and attacks, summarizes security concepts and relationships, and also describes storage security strategies. It concludes with recommended storage security plan for a total security solution.

  20. Total knee arthroplasty in vascular malformation.

    PubMed

    Bhende, Harish; Laud, Nanadkishore; Deore, Sandeep; Shashidhar, V

    2015-01-01

    In Klippel-Trenaunay syndrome, vascular malformations are not only in skin and superficial soft tissues but also in deep tissues like muscles bones and joints. It is well documemted that these recurrent intraarticular bleeds can cause early arthritis and joint pain. Performing arthroplasty in such patients is difficult and fraught with complications. We describe such a case where navigated total knee arthroplasty was performed with success to avoid the problems of intra medullary alignment used in the presence of intra medullary vascular malformations. We also suggest certain measures when knee arthroplasty is considered in such patients. PMID:26538765

  1. Regulatory aspects of total product life cycle.

    PubMed

    Hausman, Ethan D; Altaie, Sousan S

    2004-12-01

    Total Product Life Cycle (TPLC) is a conceptual framework for assessing any product or service (medical or otherwise). This article will address how the Center for Devices and Radiological Health of the U.S. Food and Drug Administration utilizes TPLC in a regulatory paradigm. TPLC will help guide the regulation of market-driven evolution of medical devices and radiation-emitting products from conception, through pre-market development, to widespread market use, and finally to obsolescence and replacement by subsequent generations of products. PMID:15684626

  2. PERIPROSTHETIC FRACTURES IN TOTAL KNEE ARTHROPLASTY

    PubMed Central

    de Alencar, Paulo Gilberto Cimbalista; De Bortoli, Giovani; Ventura Vieira, Inácio Facó; Uliana, Christiano Saliba

    2015-01-01

    The increasing number of total knee arthroplasties, in combination with the population's longer life expectancy, has led to a greater number of long-term complications. These add to the poor bone quality of elderly patients and often culminate in periprosthetic fractures. This complex orthopedic problem has a great diversity of clinical presentation. It may affect any of the bones in the knee and, because of the difficulty in finding solutions, may lead to disastrous outcomes. Its treatment requires that orthopedists should have broad knowledge both of arthroplasty techniques and of osteosynthesis, as well as an elaborate therapeutic arsenal including, for example, access to a bone bank.

  3. Catalytic Asymmetric Total Synthesis of (-)-Actinophyllic Acid.

    PubMed

    Cai, Lingchao; Zhang, Kui; Kwon, Ohyun

    2016-03-16

    Described herein is a catalytic asymmetric total synthesis of (-)-actinophyllic acid, with the key step being a chiral phosphine-catalyzed [3 + 2] annulation between an imine and an allenoate to form a pyrroline intermediate in 99% yield and 94% ee. The synthesis also features CuI-catalyzed coupling between a ketoester and a 2-iodoindole to shape the tetrahydroazocine ring; intramolecular alkylative lactonization; SmI2-mediated intramolecular pinacol coupling between ketone and lactone subunits to assemble the complex skeleton of (-)-actinophyllic acid; and an unprecedented regioselective dehydroxylation. PMID:26910382

  4. Total Elbow Arthroplasty for Distal Humerus Fractures.

    PubMed

    Harmer, Luke S; Sanchez-Sotelo, Joaquin

    2015-11-01

    Total elbow arthroplasty is a good treatment alternative for selected patients with distal humerus fractures. Its attractiveness is related to several factors, including the possibility of performing the procedure; leaving the extensor mechanism intact; faster, easier rehabilitation compared with internal fixation; and overall good outcomes reported in terms of both pain relief and function. Implant failure leading to revision surgery does happen, and patients must comply with certain limitations to extend the longevity of their implant. Development of high-performance implants may allow expanding the indications of elbow arthroplasty for fractures. PMID:26498549

  5. Stem length in revision total knee arthroplasty.

    PubMed

    Patel, Anay Rajendra; Barlow, Brian; Ranawat, Amar S

    2015-12-01

    Stems are intramedullary extensions of either the femoral or tibial component of a total knee arthroplasty (TKA) designed to increase the mechanical stability to decrease the risk of aseptic loosening. Biomechanical studies have shown that TKA stems increase the mechanical stability by transferring load over a larger area and thereby reduce strain at the bone-component interface [1-4]. The length of a revision TKA stem is determined by the patient's anatomy and the intended fixation, namely fully cemented or press-fit cortical contact. The advantages and disadvantages of various stem lengths must be weighed against the needs of the patient to achieve an optimal outcome. PMID:26371072

  6. Pathologic Processing of the Total Mesorectal Excision

    PubMed Central

    Campa-Thompson, Molly; Weir, Robert; Calcetera, Natalie; Quirke, Philip; Carmack, Susanne

    2015-01-01

    Total mesorectal excision (TME) is the current optimal surgical treatment for patients with rectal carcinoma. A complete TME is related to lower local recurrence rates and increased patient survival. Many confounding factors in the patient's anatomy and prior therapy can make it difficult to obtain a perfect plane, and thus a complete TME. The resection specimen can be thoroughly evaluated, grossly and microscopically, to identify substandard surgical outcomes and increased risk of local recurrence. Complete and accurate data reporting is critical for patient care and helps surgeons improve their technique. PMID:25733973

  7. Continuous emission monitoring total mercury analysis

    SciTech Connect

    Zepeck, R.; Kasajanow, J.

    1996-12-31

    Mercury and its compounds are emitted from various sources, coal fired power plants and waste incinerators being the prime sources. Various methods for continuous automatic monitoring of Hg or [Hg & its compounds] are being used (optical in-situ, extractive with and without sample preparation). The methods are discussed and compared. The paper also describes an automatic, continuous Total Mercury Analyzer (HM-1400), which has received Equivalency in Germany. Applications (industrial, hospital, urban, hazardous waste incinerators, waste water sludge incineration) are discussed, as well as field experience from over 7 years.

  8. Continuous emission monitoring total mercury analysis

    SciTech Connect

    Zepeck, R.; Kasajanow, J.

    1997-12-31

    Mercury and its compounds is emitted from various sources, coal fired power plants and waste incinerators being the prime sources. Various methods for continuous automatic monitoring of Hg{sup 0} or [Hg{sup 0} & its compounds] are being used (optical in-situ, extractive with and without sample preparation). The methods are discussed and compared. The paper also describes an automatic, continuous Total Mercury Analyzer (HM-1400), which has received Equivalency in Germany. Applications industrial hospital, urban, hazardous waste incinerators, waste water sludge incineration are discussed, as well as field experience front over 7 years.

  9. Soft tissue balancing in total knee arthroplasty

    PubMed Central

    MELONI, MARIA CHIARA; HOEDEMAEKER, RUSSALKA W.; VIOLANTE, BRUNO; MAZZOLA, CLAUDIO

    2014-01-01

    A good outcome in total knee arthroplasty depends on many factors: joint alignment, range of motion, patellar tracking and ligament stability. A correct soft tissue balance keeps the joint aligned in flexion and extension, and therefore constitutes the most important factor for durability of the implant. Indeed, incorrect soft tissue balancing is the primary cause of early implant failure necessitating revision surgery. Soft tissue releases, serving to correct imbalances, are performed until the flexion and extension gaps appear symmetrical and balanced. A knee is considered perfectly balanced when the flexion and extension gaps are perfectly rectangular and all the measurements are absolutely equal. PMID:25606540

  10. Total syntheses of (+)- and (-)-pestalotiopsin A.

    PubMed

    Takao, Ken-ichi; Hayakawa, Nobuhiko; Yamada, Reo; Yamaguchi, Taro; Saegusa, Hiroshi; Uchida, Masatoshi; Samejima, Suguru; Tadano, Kin-ichi

    2009-09-01

    An enantioselective total synthesis of both enantiomers of caryophyllene-type sesquiterpenoid pestalotiopsin A has been achieved, thereby establishing the absolute stereochemistry of natural (+)-pestalotiopsin A. Highlights of the synthesis include a [2 + 2] cycloaddition of N-propioloyl Oppolzer's camphorsultam and ketene dialkyl acetal and subsequent highly stereoselective 1,4-hydride addition/protonation, an aldol reaction of functionalized bicyclic lactone with aldehyde, an efficient intramolecular Nozaki-Hiyama-Kishi (NHK) reaction for the construction of the highly strained (E)-cyclononene ring, and a palladium-catalyzed reduction of allylic mesylate with retention of the E configuration. PMID:19658390

  11. Recent large fluctuations in total ozone

    NASA Technical Reports Server (NTRS)

    Newell, Reginald E.; Selkirk, Henry B.

    1988-01-01

    The present examination of total ozone changes in the global ozone network's data for the past 29 years notes recent changes to have been dominated by negative anomalies of two types: (1) reductions over the Antarctic, since 1980; and (2) deficits centered on winter and spring at middle latitudes, since 1982. Springtime correlations between ozone and temperature at the South Pole for 1963-1979 are used in linear regression models to predict ozone from temperature for the period since 1980; recent ozone values are found to be consistently lower than those predicted by these models.

  12. Total body nitrogen analysis. [neutron activation analysis

    NASA Technical Reports Server (NTRS)

    Palmer, H. E.

    1975-01-01

    Studies of two potential in vivo neutron activation methods for determining total and partial body nitrogen in animals and humans are described. A method using the CO-11 in the expired air as a measure of nitrogen content was found to be adequate for small animals such as rats, but inadequate for human measurements due to a slow excretion rate. Studies on the method of measuring the induced N-13 in the body show that with further development, this method should be adequate for measuring muscle mass changes occurring in animals or humans during space flight.

  13. Total knee arthroplasty in vascular malformation

    PubMed Central

    Bhende, Harish; Laud, Nanadkishore; Deore, Sandeep; Shashidhar, V

    2015-01-01

    In Klippel–Trenaunay syndrome, vascular malformations are not only in skin and superficial soft tissues but also in deep tissues like muscles bones and joints. It is well documemted that these recurrent intraarticular bleeds can cause early arthritis and joint pain. Performing arthroplasty in such patients is difficult and fraught with complications. We describe such a case where navigated total knee arthroplasty was performed with success to avoid the problems of intra medullary alignment used in the presence of intra medullary vascular malformations. We also suggest certain measures when knee arthroplasty is considered in such patients. PMID:26538765

  14. Near total pneumonectomy: Is it feasible?

    PubMed Central

    Philippakis, George E.; Moustardas, Marios

    2013-01-01

    INTRODUCTION There are various procedures for treating lung cancer. Segmentectomy, wedge excision, lobectomy (including bilobectomy) and pneumonectomy are the operations used to resect malignant lung tumors. We describe an operation of near total pneumonectomy for the first time in the literature. PRESENTATION OF CASE A 55 year old man with borderline respiratory function was subjected to a right upper and middle lobectomy and stapled excision of the superior segment of the right lower lobe for a right upper lobe mass invading the major fissure. DISCUSSION When operating on patients with borderline respiratory function one should always consider conservation of as much lung tissue as possible without compromising cancer clearance. CONCLUSION From the case we present, it is obvious that the remaining lung basilar segments, combined with creation of an apical pleural tent, may well function properly and add benefit to the respiratory function of such compromised patients. We believe that this operation of near total pneumonectomy may have a role in lung cancer surgery. PMID:23474978

  15. Annular and Total Solar Eclipses of 2010

    NASA Technical Reports Server (NTRS)

    Espenak, Fred; Anderson, J.

    2008-01-01

    While most NASA eclipse bulletins cover a single eclipse, this publication presents predictions for two solar eclipses during 2010. This has required a different organization of the material into the following sections. Section 1 -- Eclipse Predictions: The section consists of a general discussion about the eclipse path maps, Besselian elements, shadow contacts, eclipse path tables, local circumstances tables, and the lunar limb profile. Section 2 -- Annular Solar Eclipse of 2010 Ja n 15: The section covers predictions and weather prospects for the annular eclipse. Section 3 -- Total Solar Eclipse of 2010 Jul 11: The se ction covers predictions and weather prospects for the total eclipse. Section 4 -- Observing Eclipses: The section provides information on eye safety, solar filters, eclipse photography, and making contact timings from the path limits. Section 5 -- Eclipse Resources: The final section contains a number of resources including information on the IAU Working Group on Eclipses, the Solar Eclipse Mailing List, the NASA eclipse bulletins on the Internet, Web sites for the two 2010 eclipses, and a summary identifying the algorithms, ephemerides, and paramete rs used in the eclipse predictions.

  16. Preoperative Planning in Primary Total Knee Arthroplasty.

    PubMed

    Tanzer, Michael; Makhdom, Asim M

    2016-04-01

    Preoperative planning is of paramount importance in primary total knee arthroplasty. A thorough preoperative analysis helps the surgeon envision the operation, anticipate any potential issues, and minimize the risk of premature implant failure. Obtaining a thorough history is critical for appropriate patient selection. The physical examination should evaluate the integrity of the soft tissues, the neurovascular status, range of motion, limb deformity, and the status of the collateral ligaments to help determine the soft-tissue balancing and constraint strategy required. Standard radiographs, with a known magnification, should be obtained for preoperative total knee arthroplasty templating. Routine standing AP, lateral, and skyline radiographs of the knee can help the surgeon plan the bone cuts and tibial slope as well as the implant size and position at the time of surgery. In certain circumstances, such as severe coronal deformities, bone deficiencies, and/or extra-articular deformities, additional measures are frequently necessary to successfully reconstruct the knee. Constrained implants, metal augments, and bone graft must be part of the surgeon's armamentarium. PMID:26990712

  17. Extensor mechanism allograft in total knee arthroplasty

    PubMed Central

    Helito, Camilo Partezani; Gobbi, Riccardo Gomes; Tozi, Mateus Ramos; Flix, Alessandro Monterroso; Angelini, Fbio Janson; Pcora, Jos Ricardo

    2013-01-01

    Objective To analyze the experience with allograft transplantation of the extensor mechanism in total knee arthroplasty and compare results with the international experience. Methods We retrospectively evaluated three cases of extensor mechanism allograft after total knee arthroplasty performed in our hospital with the aid of one of the few tissue banks in Brazil and attempt to establish whether our experiences were similar to others reported in the world literature regarding patient indication, techniques, and outcomes. Results Two cases went well with the adopted procedure, and one case showed bad results and progressed to amputation. As shown in the literature, the adequate tension of the graft, appropriate tibial fixation and especially the adequate patient selection are the better predictors of good outcomes. Previous chronic infection can be an unfavorable predictor. Conclusion This surgical procedure has precise indication, albeit uncommon, either because of the rarity of the problem or because of the low availability of allografts, due to the scarcity of tissue banks in Brazil. Level of Evidence IV, Case Series. PMID:24453688

  18. Total mass of the Jupiter Trojans

    NASA Astrophysics Data System (ADS)

    Vinogradova, T. A.; Chernetenko, Yu. A.

    2015-12-01

    The total mass of the Jupiter Trojans is estimated at (0.30 ± 0.19) × 10-10 M Sun using all available physical characteristics of these asteroids. The mass of asteroids in the L4 swarm ((0.19 ± 0.11) × 10-10 M Sun) is higher than that in the L5 swarm ((0.11 ± 0.07) × 10-10 M Sun) by a factor of 1.7. The obtained estimates include the hidden mass of asteroids that are not discovered yet. This hidden component constitutes 7% of the total mass. The number of Trojans with diameters larger than 1 km is estimated at 6 × 105. The number of such asteroids at the L4 Lagrangian point ( N L4 = 4 × 105) is two times higher than that at the L5 Lagrangian point ( N L5 = 2 × 105). It is found that the N L4/ N L5 ratio is increased at smaller asteroid sizes or higher absolute magnitudes H. This ratio equals just 1.3 for asteroids with H <11m (i.e., asteroids with diameters D > 30 km). The effect of gravitational perturbations from Trojans on the motion of Hildian asteroids and centaurs is evaluated. This effect turned out to be at the limit of accuracy of modern observations.

  19. Previous gastric bypass surgery complicating total thyroidectomy.

    PubMed

    Alfonso, Bianca; Jacobson, Adam S; Alon, Eran E; Via, Michael A

    2015-03-01

    Hypocalcemia is a well-known complication of total thyroidectomy. Patients who have previously undergone gastric bypass surgery may be at increased risk of hypocalcemia due to gastrointestinal malabsorption, secondary hyperparathyroidism, and an underlying vitamin D deficiency. We present the case of a 58-year-old woman who underwent a total thyroidectomy for the follicular variant of papillary thyroid carcinoma. Her history included Roux-en-Y gastric bypass surgery. Following the thyroid surgery, she developed postoperative hypocalcemia that required large doses of oral calcium carbonate (7.5 g/day), oral calcitriol (up to 4 ?g/day), intravenous calcium gluconate (2.0 g/day), calcium citrate (2.0 g/day), and ergocalciferol (50,000 IU/day). Her serum calcium levels remained normal on this regimen after hospital discharge despite persistent hypoparathyroidism. Bariatric surgery patients who undergo thyroid surgery require aggressive supplementation to maintain normal serum calcium levels. Preoperative supplementation with calcium and vitamin D is strongly recommended. PMID:25738720

  20. On the total mass of closed universes

    NASA Astrophysics Data System (ADS)

    Szabados, Lszl B.

    2013-11-01

    The total mass, the Witten type gauge conditions and the spectral properties of the Sen-Witten and the 3-surface twistor operators in closed universes are investigated. It has been proven that a recently suggested expression for the total mass density of closed universes is vanishing if and only if the spacetime is flat with toroidal spatial topology; it coincides with the first eigenvalue of the Sen-Witten operator; and it is vanishing if and only if Wittens gauge condition admits a non-trivial solution. Here we generalize slightly the result above on the zero-mass configurations: if and only if the spacetime is holonomically trivial with toroidal spatial topology. Also, we show that the multiplicity of the eigenvalues of the (square of the) Sen-Witten operator is even, and a potentially viable gauge condition is suggested. The monotonicity properties of through the examples of closed Bianchi I and IX cosmological spacetimes are also discussed. A potential spectral characterization of these cosmological spacetimes, in terms of the spectrum of the Riemannian Dirac operator and the Sen-Witten and the 3-surface twistor operators, is also indicated.