Gelaude, Frederik; Clijmans, Tim; Delport, Hendrik
A novel quantitative, computerized, and, therefore, highly objective method is presented to assess the degree of total radical acetabular bone loss. The method, which is abbreviated to “TrABL”, makes use of advanced 3D CT-based image processing and effective 3D anatomical reconstruction methodology. The output data consist of a ratio and a graph, which can both be used for direct comparison between specimens. A first dataset of twelve highly deficient hemipelves, mainly Paprosky types IIIB, is used as illustration. Although generalization of the findings will require further investigation on a larger population, it can be assumed that the presented method has the potential to facilitate the preoperative use of existing classifications and related decision schemes for treatment selection in complex revision cases. PMID:22013539
Pereira, G. C.T.; Kubiak, E. N.; Levine, B.; Chen, F. S.
The use of impacted morselized cancellous bone grafts in conjunction with cementless hemispherical acetabular cups for treatment of AAOS type II acetabular cavitary deficiencies was evaluated in a retrospective study of 23 primary and 24 revision total hip arthroplasties, at a mean follow-up of 7.9 and 8.1 years, respectively. All primary hips received autografts, while all revision hips received allografts. Modified Harris Hip Scores for primary and revision hip replacements increased from a pre-operative mean of 37 and 47 to a postoperative mean of 90 and 86, respectively. All 23 autografts and 23 out of 24 cancellous allografts were radiographically incorporated without evidence of resorption. There were no instances of infection, component migration, or cases requiring subsequent acetabular revision. We conclude that impacted morselized cancellous bone-graft augmentation of cementless cups is a viable surgical option for AAOS type II cavitary acetabular defects. PMID:16988799
The aim of the study is to determine failure of the cemented polyethylene acetabular component, which might occur due to excessive bone resorption, cement-bone interface debonding and fatigue failure of the cement mantle. Three-dimensional finite element models of intact and implanted pelvic bone were developed and bone remodeling algorithm was implemented for present analysis. Soderberg fatigue failure diagram was used for fatigue assessment of the cement mantle. Hoffman failure criterion was considered for prediction of cement-bone interface debonding. Results indicate fatigue failure of the cement mantle and implant-bone interface debonding might not occur due to bone remodeling.
Pierannunzii, L; Mambretti, A; D'Imporzano, M
Current evidences in revision hip arthroplasty suggest to treat severe acetabular bone loss with dedicated implants, such as anti-protrusio cages, stemmed cups, modular systems supplied with iliac flanges and obturatory hook. However recent literature is reporting satisfactory outcomes with simple elliptical Trabecular Metal cups. Purpose of the study was to evaluate mid-term results of such a surgical procedure. All hip revisions performed from 2008 to 2009 with implantation of a TMT multi-hole acetabular cup without augmentations were retrospectively reviewed. The cases with low-degree acetabular bone loss (stage I and II according to GIR classification), with surgical report poorly describing the bone defect, with inadequate pre- and post-operative x-rays were ruled out. Twenty-five cases were identified, but four were lost to follow-up. The twenty-one patients were 71 year-old on average (from 60 to 82), with stage IV bone loss in 6 cases and stage III bone loss in 15 cases. Mean interval from surgery to evaluation was 20.9 months (from 13 to 30). The evaluation included bone-prosthesis contact estimation, component position, survivorship, complications, final Harris Hip Score, presence of periprosthetic radiolucencies. Host bone-prosthesis contact was estimated to be about 35%. Only three implant were subsequently reoperated (for infection, early migration, recurrent dislocation). The HHS among non-reoperated 18 patients was 81.96 on average (from 63.44 to 95.82). Six cases showed thin radiolucencies in one of the three Charnley zones, while three cases showed radiolucencies in two. None of these images was evolutive, thus they were not considered signs of loosening. The mid-term results of this series confirm the hypothesis that a porous tantalum acetabular cup is an effective option to deal with difficult acetabular revisions. Although no extra-acetabular fixation device is available, the very high surface friction guaranteed by the material and the
Rosito, Ricardo; Galia, Carlos Roberto; Macedo, Carlos Alberto Souza; Moreira, Luis Fernando; Quaresma, Lourdes Maria Araújo C.; Palma, Humberto Moreira
BACKGROUND This is a cohort trial (1997–2005) of 49 patients submitted to an acetabular component revision of a total hip arthroplasty, using impacted human and bovine freeze-dried cancellous bone grafts (H&FDBG) and a reinforcement device. OBJECTIVE To compare clinical/radiographic graft incorporation capability between cancellous bone grafts. PATIENTS/METHODS There were two groups: I (n=26) receiving human grafts and II (n=25) receiving bovine grafts. The average follow-up times were 55 and 49 months, respectively. Clinical analysis was based on the Merle d’Aubigné and Postel score, and the radiographic analysis involved an established score based on Conn’s et al. criteria for radiographic bone incorporation. RESULTS No clinical/radiographic differences were found between the groups and both showed an overall rate of 88.5% and 76% of graft incorporation (p=0.424). CONCLUSION The results presented here are comparable to those in the literature with the use of deep-FG. Therefore, cancellous bone grafts can be safely and adequately used in acetabular component revision in total hip arthroplasty. PMID:18719763
Nakashima, Yasuharu; Nakamura, Tetsuro; Ito, Yoshihiro; Hara, Toshihiko
Objectives. To determine the minimum lateral bone coverage required for securing stable fixation of the porous-coated acetabular components (cups) in hip dysplasia. Methods. In total, 215 primary total hip arthroplasties in 199 patients were reviewed. The average follow-up period was 49 months (range: 24–77 months). The lateral bone coverage of the cups was assessed by determining the cup center-edge (cup-CE) angle and the bone coverage index (BCI) from anteroposterior pelvic radiographs. Further, cup fixation was determined using the modified DeLee and Charnley classification system. Results. All cups were judged to show stable fixation by bone ingrowth. The cup-CE angle was less than 0° in 7 hips (3.3%) and the minimum cup-CE angle was −9.2° (BCI: 48.8%). Thin radiolucent lines were observed in 5 hips (2.3%), which were not associated with decreased lateral bone coverage. Loosening, osteolysis, dislocation, or revision was not observed in any of the cases during the follow-up period. Conclusion. A cup-CE angle greater than −10° (BCI > 50%) was acceptable for stable bony fixation of the cup. Considering possible errors in manual implantation, we recommend that the cup position be planned such that the cup-CE angle is greater than 0° (BCI > 60%). PMID:28299327
Hsu, Jui-Ting; Lin, Dan-Jae
Acetabular cup loosening is one of the major failure models of total hip replacement (THR), which is mostly due to insufficient initial stability of the cup. Previous studies have demonstrated that cup stability is affected by the quality of the host bone and the surgical skill when inserting screws. The purpose of this study was to determine the effects on the initial stability of the acetabular cup of eccentric screws in bone of different qualities. In this study, hemispherical cups were fixed into bone specimens constructed from artificial foam with three elastic moduli using one to three screws. The effects of two types of screw eccentricity (offset and angular) on the stability of the acetabular cup were also evaluated. The experimental results indicate that in the presence of ideal screwing, the cup was stable in bone specimens constructed from foam with the highest elastic modulus. In addition, increasing the number of ideal screws enhanced the cup stability, especially in bone specimens constructed from soft foam. Moreover, the cup stability was most affected by offset eccentric screw(s) in the hard-foam bone specimens and by angular eccentric screw(s) in the soft-foam bone specimens. The reported results indicate that the presence of screw eccentricity affects the initial stability of the acetabular cup. Surgeons should keep this in mind when performing screw insertions in THR. However, care is necessary when translating these results to the intraoperative situation due to the experiments being conducted under laboratory conditions, and hence, future studies should attempt to replicate the results reported here in vivo.
Veerappa, L A; Tripathy, S K; Sen, R K
Management of neglected acetabular fractures is a difficult task. Osteosynthesis in such cases may not be an ideal solution because of the femoral head damage due to pressure by the fractured acetabular edge, avascular necrosis, difficulty in mobilizing the fragments due to callus formation, difficulty in indirect reduction of the fracture fragments and macerated acetabular fragments all contributing to inadequate fracture reduction. Majority of such fractures are now treated with total hip replacement. While treating such fractures with THR, problems associated with neglected acetabular fractures such as fracture non-union, hip dislocation, protrusio, cavitary bone defect or peripheral bone defect must be considered. 3D computed tomography scan provides a clear view about the acetabular and periacetabular bony anatomy. Impaction grafting and antiprotrusio cage or ring with a cemented acetabular cup can address most of the hip protrusio and cavitary bone defects. Segmental bone defect needs cortical strut-bone graft fixation and subsequent implantation of a cemented or uncemented acetabular cup implantation. Fracture non-union needs approximate reduction and fixation with plates followed by bone grafting and implantation of an acetabular cup. Despite these efforts, the outcome of THR in neglected acetabular fracture is considerable worse than after conventional hip replacement.
Acetabular revision with impaction bone grafting and a cemented polyethylene acetabular component: comparison of the Kaplan-Meier analysis to the competing risk analysis in 62 revisions with 25 to 30 years follow-up.
Te Stroet, M A J; Keurentjes, J C; Rijnen, W H C; Gardeniers, J W M; Verdonschot, N; Slooff, T J J H; Schreurs, B W
We present the results of 62 consecutive acetabular revisions using impaction bone grafting and a cemented polyethylene acetabular component in 58 patients (13 men and 45 women) after a mean follow-up of 27 years (25 to 30). All patients were prospectively followed. The mean age at revision was 59.2 years (23 to 82). We performed Kaplan-Meier (KM) analysis and also a Competing Risk (CR) analysis because with long-term follow-up, the presence of a competing event (i.e. death) prevents the occurrence of the endpoint of re-revision. A total of 48 patients (52 hips) had died or had been re-revised at final review in March 2011. None of the deaths were related to the surgery. The mean Harris hip score of the ten surviving hips in ten patients was 76 points (45 to 99). The KM survivorship at 25 years for the endpoint 're-revision for any reason' was 58.0% (95% confidence interval (CI) 38 to 73) and for 're-revision for aseptic loosening' 72.1% (95% CI 51 to 85). With the CR analysis we calculated the KM analysis overestimates the failure rate with respectively 74% and 93% for these endpoints. The current study shows that acetabular impaction bone grafting revisions provide good clinical results at over 25 years.
Dihlmann, S W; Ochsner, P E; Pfister, A; Mayrhofer, P
Out of 57 revised acetabular components, which were regularly checked, 47 had been replaced by a cemented Müller's acetabular reinforcement ring resp. a cementless Müller's Sl-shell with flange. Both types of cups are anchored in the acetabular roof with cancellous bone screws (tab. 1). 42 cases with radiograph series permitted a detailed analysis with the EBRA-method, a computer aided method for the evaluation of acetabular spatial migration based on standard radiographs of the pelvis. The clinical results were very satisfying (tab. 6). The screwed acetabular components migrated little, although, some essential displacements of the center of rotation (in relation to the anatomical position) had to be accepted. As was recognizable with today's inaccurate methods of measuring the center of the head, the displacement too far towards cranial influenced the migration tendency less than an excessive lateralisation. Especially satisfying is the fact, that no increased migration was observed after reconstruction bone grafting of severe acetabular defects, provided that at least a partly direct contact between the acetabular component and the original bone stock was obtained. For the first time EBRA shall be introduced here as a method which shows the migration and the spatial inclination of the acetabular cup in a vector chart.
RISSECH, C.; SAÑUDO, J. R.; MALGOSA, A.
The acetabular point was analysed by studying human pelvic bones from 326 individuals ranging from newborns to age 97 y. The bones were categorised into 3 groups according to the degree of fusion for the 3 elements of the pelvis: nonfused (59), semifused (5) and fused (262). The acetabular point in immature pelvic bones is clearly represented by the point of the fusion lines for each bony element at the level of the acetabular fossa. In adult pelvic bones the acetabular fossa has an irregular clover-leaf shape, the superior lobe being smaller than the anterior and posterior lobes. Cross-sectional analysis of acetabular morphology suggested that the acetabular point in adult pelvic bones is always represented by the indentation between the superior and the anterior lobes of the acetabular fossa. PMID:11465866
Saus Milán, N; Pino Almero, L; Mínguez Rey, M F
The bone cyst is a rare benign tumor that usually develops in childhood. There are several treatment options, however when it is located within the pelvis treatment is complex. A 7 year-old patient who presented with 3 months of right hip pain and limping. The initial radiograph showed a discrete periostic reaction and acetabulum effacement. The MRI and CT scans suggested the diagnosis of aneurysmal bone cyst and was confirmed by open biopsy. Two serial embolizations were performed with good results, the patient was asymptomatic one year after.
Sabokbar, A; Crawford, R; Murray, D W; Athanasou, N A
A macrophage infiltrate is commonly found in enlarging subchondral cysts in osteoarthrosis (OA) and the surrounding bone. To determine whether osteoclast differentiation by these cells contributes to the increase in the number of osteoclasts and bone resorption that accompanies OA cyst enlargement, we isolated macrophages from the wall of OA cysts and co-cultured them with osteoblast-like UMR106 cells in the presence or absence of 1,25(OH)2D3 and M-CSE After 14 days of incubation, co-cultures of UMR106 cells and cyst-derived macrophages showed evidence of osteoclast differentiation by expression of TRAP, VNR and formation of numerous lacunar pits. We found that, unlike osteoclast precursors in monocyte and other tissue macrophage populations, the addition of M-CSF to medium is not required for osteoclast differentiation. Our findings suggest that macrophage-osteoclast differentiation is one means whereby the osteolysis associated with the enlargement of OA cysts could be effected.
Nie, Yong; Pei, Fuxing; Shen, Bin; Kang, Pengde; Li, Zongming
The basic stress pathway above the acetabular dome is important for the maintenance of implant stability in press-fit acetabular reconstruction of total hip arthroplasty. However, information on the basic stress pathway and its impact factors remains unclear. The objective of this study was to investigate the effects of the orientations and positions of the acetabular component on the basic stress pathway. The basic stress pathway above the acetabular dome was defined as two parts: 3D basic trabecular bone stress distribution and quantified basic cortical bone stress level, using two subject-specific finite element normal hip models. The effects were then analysed by generating 32 reconstructed acetabular cases with different cup abduction and anteversion angles within a range of 35-50° and 10-25°, respectively, and 12 cases with different hip centre heights within a range of 0-15 mm above the acetabular dome. The 3D trabecular stress distribution decreased remarkably in all cases, while the 80% of the basic cortical bone stress level was maintained in cases when the acetabular component was positioned at 10° or 15° anteversion and 40° or 45° abduction angles. The basic stress pathway above the acetabular dome was disturbed when the superior displacement of the hip centre exceeded 5 mm above the anatomical hip centre. Positioning the acetabular component correctly contributes to maintain the stress balance between the acetabular cup and the bone during acetabular reconstruction, thus helping restore the normal hip biomechanics and preserve the stability of the implants.
Batuyong, Eldridge D; Brock, Hugh S; Thiruvengadam, Nikhil; Maloney, William J; Goodman, Stuart B; Huddleston, James I
Porous tantalum acetabular implants provide a potential solution for dealing with significant acetabular bone loss. This study reviews 24 acetabular revisions using tantalum implants for Paprosky type 3 and 4 defects. The mean Harris Hip Score improved from 35 ± 19 (range, 4-71) to 88 ± 14 (range, 41-100), p < 0.0001. Postoperative radiographs showed radiolucent lines in 14 hips with a mean width of 1.3 ± 1.0 mm (range, 0.27-4.37 mm). No gaps enlarged and 71% of them disappeared at a mean of 13 ± 10 months (range, 3-29 months). At a mean follow-up of 37 ± 14 months (range, 24-66 months), 22 reconstructions showed radiograpic evidence of osseointegration (92%). The two failures were secondary to septic loosening. When dealing with severe acetabular bone loss, porous tantalum acetabular components show promising short-term results.
Saisu, Takashi; Kamegaya, Makoto; Wada, Yuichi; Takahashi, Kenji; Mitsuhashi, Shigeru; Moriya, Hideshige; Maier, Markus
We conducted this animal study to demonstrate whether exposing the acetabulum in immature rabbits to extracorporeal shock waves induces bone formation in the acetabulum. Five thousand shock waves of 100 MPa each were directed, from outside, at the acetabular roof of eight immature rabbits. At each of two time points (4 and 8 weeks) after treatment, the pelvises of four rabbits were removed and evaluated morphologically. Woven bone formation was observed on the lateral margin of the acetabular roof at 4 weeks after treatment, and the breadth of the acetabular roof in the coronal plane was significantly increased. Eight weeks after treatment, the woven bone disappeared; the breadth of the acetabular roof, however, was significantly increased. These findings demonstrated that extracorporeal shock waves induced acetabular augmentation in rabbits. We conclude that extracorporeal shock waves, perhaps, could be applied clinically for the treatment of acetabular dysplasia.
Krepelka, Mircea; Toth-Taşcǎu, Mirela
Stress shielding is increasingly recognized as an important cause of acetabular component failure. Several studies have been focused on improving the acetabular component placement to reduce the risk of dislocation, impingement and range of motion but little is known of its influence on implant-bone interface pressures. This study employs experimental design, 3D reconstruction and FE simulation to identify the most significant factors for acetabular component behavior and predict the best configuration of acetabular spatial orientation angles within the constraints of the Lewinnek's safe zone in order to minimize peak contact pressures. Data analysis by response surface method revealed that the magnitude of periacetabular pressures was significantly reduced by the anteversion angle at its lowest value as well as the abduction angle located at the central point value, which corresponded to a 40° abduction and 5° anteversion of cup orientation.
Xiao, Jian-Lin; Zuo, Jian-Lin; Liu, Peng; Qin, Yan-Guo; Li, Xue-Zhou; Liu, Tong; Gao, Zhong-Li
Background: Many clinical studies have been published involving the use of a high hip center (HHC), achieved good follow-up. However, there is a little anatomic guidance in the literature regarding the amount of bone stock available for initial implant coverage in this area of the ilium. The purpose of this study was to evaluate the thickness and width of the human ilium and related acetabular cup coverage for guiding acetabular component placement in HHC. Methods: A total of 120 normal hips in 60 cases of adult patients from lower extremities computer tomographic angiography Digital Imaging and Communications in Medicine data were chosen for the study. After importing the data to the mimics software, we chose the cross sections every 5-mm increments from the rotational center of the hip to the cephalic of the ilium according the body sagittal axis, then we measured the thickness and width of the ilium for each cross section in axial plane, calculated the cup coverage at each chosen section. Results: At the acetabular dome, the mean thickness and width of the ilium were 49.71 ± 4.88 mm and 38.92 ± 3.67 mm, respectively, whereas at 1 cm above the dome, decreased to 41.35 ± 5.13 and 31.13 ± 3.37 respectively, and 2 cm above the dome, decreased to 31.25 ± 4.04 and 26.65 ± 3.43, respectively. Acetabular cup averaged coverage for 40-, 50-, and 60-mm hemispheric shells, was 100%, 89%, and 44% at the acetabular dome, 100%, 43.7%, and 27.5% for 1 cm above the dome, and 37.5%, 21.9%, and 14.2% for 2 cm above the dome. Conclusions: HHC reconstructions within 1 cm above the acetabular dome will be an acceptable and smaller diameter prosthesis would be better. PMID:26063357
ElMaraghy, Amr W.; Schemitsch, Emil H.; Waddell, James P.
Objective To determine the immediate effect of reaming and insertion of the acetabular component with and without cement on periacetabular blood flow during primary total hip arthroplasty (THA). Design A clinical experimental study. Setting A tertiary referral and teaching hospital in Toronto. Patients Sixteen patients (9 men, 7 women) ranging in age from 30 to 78 years and suffering from arthritis. Intervention Elective primary THA with a cemented (8 patients) and noncemented (8 patients) acetabular component. All procedures were done by a single surgeon who used a posterior approach. Main outcome measure Acetabular bone blood-flow measurements made with a laser Doppler flowmeter before reaming, after reaming and after insertion of the acetabular prosthesis. Results Acetabular blood flow after prosthesis insertion was decreased by 52% in the noncemented group (p < 0.001) and 59% in the cemented group (p < 0.001) compared with baseline (prereaming) values. Conclusion The significance of these changes in periacetabular bone blood flow during THA may relate to the extent of bony ingrowth, periprosthetic remodelling and ultimately the incidence of implant failure because of aseptic loosening. PMID:10851413
Ritschl, P; Machacek, F; Strehn, L; Kloiber, J
The patella replacement in revision surgery is a challenge especially in cases of unsufficient bone stock. Depending on the extent of the bone defect, the following videos demonstrate different approaches: Video 1: bone sparing removal of the patella implant: onlay-type patella implants. Video 2: complete cortical bone rim of the patella, residual thickness between 6 to 10 mm: biconvex patella implant. Video 3 and 4: small defects of the cortical bone rim of the patella, residual thickness 1 to 5 mm (patella shell): gull-wing osteotomy, patella bone grafting techniques. Video 5: partial necrosis/defect of the patella shell with incomplete cortical bone rim: porous tantalum patella prosthesis. On account of the various surgical options for different bone defects of the patella, patellectomy and pure patelloplasty should be avoided to prevent functional shortcomings.
Kim, Youngwoo; Tanaka, Chiaki; Kanoe, Hiroshi
We evaluated the clinical results of the reconstruction of acetabular bone deficiency using hydroxyapatite (HA) granules and structural autografts supported by a Kerboull-type acetabular reinforcement device at a minimum of 10 years follow-up. Between 1993 and 2003, 40 consecutive THA revisions were performed in 37 patients with a mean age of 66.4 years. The mean follow-up period was 12.8 years. Radiologically, 5 hips failed, of which 2 were revised. The survival rate of the acetabular component at 10 years was 100% in type II defects and 94.9% in the type III defects, using acetabular revision for loosening as the end point. Acetabular reconstruction with HA granules, structural autografts and a Kerboull-type acetabular reinforcement device provided satisfactory clinical and radiological results at 12.8 years postoperatively.
Springer, Bryan D; Hanssen, Arlen D; Lewallen, David G
Cementing a polyethylene liner into a well-fixed acetabular shell during revision hip arthroplasty may be appropriate in select patients. The purpose of this study was to review our early results with this technique. Sixteen patients with >2-year follow-up or who had any complications at <2 years from surgery were identified. Indications for this technique included: failure of the previous locking mechanism, significant polyethylene wear, malposition of the well-fixed metal shell, and previous removal of the liner with a retained acetabular shell. One acetabular shell has been revised at 13 months for multiple dislocations. Hip scores improved an average of 24.2 points. Radiographs revealed no polyethylene dissociation or acetabular loosening. Complications occurred in 7 patients. Initial results appear successful at providing secure fixation, while preventing the bone loss that might occur with removal of a well-fixed component.
Crosnier, Emilie A; Keogh, Patrick S; Miles, Anthony W
Initial stability is an essential prerequisite to achieve osseointegration of press-fit acetabular cups in total hip replacements. Most in vitro methods that assess cup stability do not reproduce physiological loading conditions and use simplified acetabular models with a spherical cavity. The aim of this study was to investigate the effect of bone density and acetabular geometry on cup stability using a novel method for measuring acetabular cup micromotion. A press-fit cup was inserted into Sawbones(®) foam blocks having different densities to simulate normal and osteoporotic bone variations and different acetabular geometries. The stability of the cup was assessed in two ways: (a) measurement of micromotion of the cup in 6 degrees of freedom under physiological loading and (b) uniaxial push-out tests. The results indicate that changes in bone substrate density and acetabular geometry affect the stability of press-fit acetabular cups. They also suggest that cups implanted into weaker, for example, osteoporotic, bone are subjected to higher levels of micromotion and are therefore more prone to loosening. The decrease in stability of the cup in the physiological model suggests that using simplified spherical cavities to model the acetabulum over-estimates the initial stability of press-fit cups. This novel testing method should provide the basis for a more representative protocol for future pre-clinical evaluation of new acetabular cup designs.
Figueras, Guillem; Planell, Ramón Vives; Fernàndez, Ramón Serra; Biayna, Joan Camí
Background: As a consequence of use of metal-on-metal hip arthroplasties some patients have precised revision for pain or metal hipersensivity reactions among other causes. We propose to salvage monoblock acetabular component and femoral component using a dual-mobility head and perform a lower morbidity operation in young patients preserving host bone stock in cases with well fixed and positioned components. Objective: (1) What clinical problems have been reported in patients with Metal-on-metal hip arthroplasties? (2) Could the tribocorrosion potentially cause a fracture of neck femoral component? (3) Can be the dual-mobility head a recourse in metal-on-metal hip revision? Methods: Ten patients were revised for pain or/and raised Cobalt/Chromium levels between August 2012 and December 2015. In three cases femoral neck component was fractured and femoral revision was necessary. In four hips, acetabular and femoral components could be maintained. Age, body index mass, ion levels, acetabular position, size of acetabular component and femoral head, approach, blood transfunsion and time of hospitalization were analized. Results: At a mean follow-up of 25,6 months (6 to 45) the mean postoperative HHS was 92. It was not statistically significant because several patients were low sintomatic before surgery, but had raised Cobalt/Chromium levels in the blood. All patients had near-normal levels of Cobalt/Chromium during the first 6 months after revision surgery. No relevant complications were reported. Conclusion: The use of dual-mobility head can be an acceptable option to revise metal-on-metal arthroplasties correctly oriented with abscence of loosening or infection signs and keeping bone stock in young patients. PMID:27857822
Judas, Fernando M.; Lucas, Francisco M.; Fonseca, Ruben L.
Introduction The removal of a well-fixed acetabular component in a total hip arthroplasty can cause bone fractures, excessive bleeding, as well as extended bone loss. The reimplantation of a new acetabular component may be compromised. Presentation of case We report a technique using 2 cork-screws for removal a stable cemented acetabular component for the treatment of a recurrent dislocation of a cemented total hip arthroplasty, due to acetabular malposition. Discussion A diversity of approaches and tools has been used for extraction of the acetabular prosthesis. Using 2 cork-screws it is possible to create fissures and fractures into the cement mantle, and greater manual control is obtained facilitating the manipulation of the acetabular component in different directions. The cup-cemented bond can be disrupted, the host bone is preserved and the risks of complications are minimized. Conclusion This technique is simple, available in any environment, reproducible, non-costly, non-timing consuming and safe. PMID:25725330
Bianchi, Luca; Galante, Claudio; Zagra, Luigi
Following the increasing number of total hip arthroplasties, the amount of hip revision procedures continue to rise. Careful patient selection and bone loss evaluation is crucial for a correct management of femoral revision procedures. The key point in femoral revision is to obtain a reliable primary stability of the stem, with the least invasive implant as possible, to preserve and if possible to restore the bone stock. In this article we present the indications and the techniques for the femoral revisions most commonly used in Europe, referring to the evidence in the literature and our personal experiences.
Jain, Rina; Schemitsch, Emil H.; Waddell, James P.
Objective To evaluate the effects of clinical factors on outcome after acetabular revision with a cementless beaded cup. Design Retrospective case series. Setting Tertiary care referral centre. Patients Forty-one patients who underwent acetabular revision with a cementless cup were followed up for a mean of 3.4 years. Interventions Acetabular revision with a beaded cementless cup in all patients. A morcellized allograft was used in 10 patients. Outcome measures A modified Harris hip score (range of motion measurement omitted), the SF-36 health survey, and the Western Ontario McMaster (WOMAC) osteoarthritis index. Multivariate analysis was used to evaluate the effects of age, gender, morcellized allografting, time to revision from the previous operation, acetabular screw fixation and concurrent femoral revision on outcome. Results Gender accounted for a significant portion of the variation seen in the SF-36 physical component scores (r = 0.36, p = 0.02), with women tending to have worse results. Increasing age was associated with lower WOMAC index function scores (r = 0.36, p = 0.03), whereas concurrent femoral revision tended to have a positive effect on WOMAC index function (r = 0.39, p = 0.01). None of the potential clinical predictors had any significant effect on the SF-36 mental component scores, or WOMAC index pain and stiffness scores. Conclusions In cementless acetabular revision arthroplasty, physical function, as measured by generic and limb-specific scales, may be affected by gender, age and the presence of a concurrent femoral revision. Time to revision from the previous operation, morcellized allografting and screw fixation of the acetabulum did not affect outcomes. This information may provide some prognostic value for patients’ expectations. PMID:10948687
Kindynis, P; Garcia, J
Acetabular protrusion refers to intrapelvic displacement of the medial wall of the acetabulum and is defined as inward movement of the acetabular line so that the distance between this line and the laterally located ilioischial line is 3 mm or more in adult men and 6 mm or more in adult women. As discussed in this article, acetabular protrusion may be found in many bone disorders such as degenerative joint disease, Paget's disease, rheumatoid arthritis, ankylosing spondylitis, osteomalacia, Marfan's disease and as an effect of irradiation. Protrusio acetabuli appearing in absence of any recognizable cause is termed primary acetabular protrusion or Otto pelvis. Primary acetabular protrusion usually affects both hips in young to middle aged women with a history of diminished abduction, rotation and hip pain since puberty. Radiographically one notes a bilateral axial migration of the femoral head without joint space loss and with moderate degenerative changes.
Cibulka, Michael T
Acetabular retroversion has been recently implicated as an important factor in the development of femoral acetabular impingement and hip osteoarthritis. The proper function of the hip joint requires that the anatomic features of the acetabulum and femoral head complement one another. In acetabular retroversion, the alignment of the acetabulum is altered where it opens in a posterolaterally instead of anterior direction. Changes in acetabular orientation can occur with alterations in pelvic tilt (anterior/posterior), and pelvic rotation (left/right). An overlooked problem that alters pelvic tilt and rotation, often seen by physical therapists, is sacroiliac joint dysfunction. A unique feature that develops in patients with sacroiliac joint dysfunction (SIJD) is asymmetry between the left and right innominate bones that can alter pelvic tilt and rotation. This article puts forth a theory suggesting that acetabular retroversion may be produced by sacroiliac joint dysfunction.
Silva, Paulo; de Oliveira, Leandro Alves; Coelho, Danilo Lopes; do Amaral, Rogério Andrade; Rebello, Percival Rosa; de Moraes, Frederico Barra
To describe a new procedure of total hip replacement in patient with severe developmental dysplasia of the left hip, using technique of acetabular reconstruction with autogenous bone grafts and subtrochanteric shortening femoral osteotomy. Total hip replacement done in January of 2003. The Eftekhar's classification was used and included type D, neglected dislocations. Bone graft incorporated in acetabular shelf and femoral osteotomy. Our contribution is the use of an Allis plate to better fix acetabular grafts, avoiding loosening, and cerclage around bone graft in femoral osteotomy site, which diminish pseudoarthrosis risk. This technique shows efficiency, allowing immediately resolution for this case with pain and range of motion of hip improvement. It also allows the acetabular dysplasia reconstruction, equalization of the limb length (without elevated risk of neurovascular lesion) and repairs the normal hip biomechanics due to the correction of the hip's center of rotation.
Langley-Hobbs, S J; Sissener, T R; Shales, C J
The surgical repair of acetabular physeal fractures in four kittens using a screw and tension band technique is reported. This was an appropriate method for restoring articular congruency and improving pelvic alignment. All cases had an excellent outcome and full limb use following fracture repair. In kittens younger than 12 weeks, there is a possibility of premature fusion of the acetabular bone resulting in development of a deformed, shallow acetabulum and hip subluxation. However, surgery is still justified when there is pelvic canal narrowing to decrease the risk of future defecatory problems. Early implant removal in such young kittens may decrease the severity of deformity caused by premature physeal closure. In kittens of 16 weeks or older, the prognosis is good for normal acetabular development and implant removal is not necessary.
Schmidutz, Florian; Sprecher, Christoph M; Milz, Stefan; Gohlke, Frank; Hertel, Ralph; Braunstein, Volker
Cementless-surface-replacement-arthroplasty (CSRA) of the shoulder aims for functional joint restoration with minimal bone loss. Good clinical results have been reported, but due to the radiopaque metal shell no data is available on the structure, osseous integration, and bone stock under the implant. 14 hemi-CSRAs (4 manufacturers) with two geometries (crown [n = 7]/ stem [n = 7] fixation) were retrieved from patients undergoing revision due to glenoidal erosion. Histological sections cutting through the implant centre and bone were analysed. Quantitative histomorphometry evaluated the bone-implant-contact and compared the bone-area to native humeral retrievals (n = 7). The bone-implant-interface was further assessed by scanning-electron-microscopy (SEM) and energy-dispersive-x-ray (EDX). Qualitative histology revealed a reduced and inhomogeneous bone stock. Obvious signs of stress shielding were observed with bone predominantly visible at the stem and implant rim. Quantitative histomorphometry confirmed the significantly reduced bone-area (9.2 ± 3.9% [crown 9.9 ± 4.3%, stem 8.6 ± 3.6%]) compared to native humeri (21.2 ± 9.1%; p < 0.05). Bone-implant-contact was 20.5 ± 5.8% (crown 21.8 ± 6.2%, stem 19.2 ± 5.6%) which was confirmed by SEM and EDX. Altogether, CRSA shows satisfactory bone ingrowth at the interface suggesting sufficient primary stability to allow osseous integration. However, clear signs of stress shielding with an inhomogeneous and reduced bone stock were observed. The impact on the long-term-results is unclear requiring further investigation.
Xu, Meng; Zhang, Li-Hai; Zhang, Ying-Ze; He, Chun-Qing; Zhang, Li-Cheng; Wang, Yan; Tang, Pei-Fu
Site-specific locking plates have gained popularity for the treatment of fractures. However, the clinical use of a site-specific locking plate for acetabular fractures remains untested due to production limits. To design a universal site-specific locking plate for acetabular fractures, the 3-dimensional (3D) photographic records of 171 pelvises were retrospectively studied to generate a universal posterior innominate bone surface. Using 3D photographical processing software, the 3D coordinate system was reset according to bony landmarks and was scaled based on the acetabular diameter to allow a direct comparison between surfaces. The measured surface was separated into measurement units. At each measurement unit, the authors calculated the average z-axis values in all samples and obtained the 3D coordinate values of the point cloud that could be reconstructed into the universal surface. A plate was subsequently designed in 3D photographical processing software, and the orientation and distribution of locking screws was included. To manufacture a plate, the data were entered into Unigraphics NX version 6.0 software (Siemens PLM Software, Co, Ltd, Plano, Texas) and a CNC digital milling machine (FANUC Co, Ltd, Yamanashi, Japan). The resulting locking plate fit excellently with the reduced bone surface intraoperatively. Plate contouring was avoided intraoperatively. Universal 3.5-mm locking screws locked successfully into the plate, and their orientations were consistent with the design. No screw yielded to acetabular penetration. This method of designing a site-specific acetabular locking plate is practical, and the plates are suitable for clinical use. These site-specific locking plates may be an option for the treatment of acetabular fractures, particularly in elderly patients.
San-Millán, Marta; Rissech, Carme; Turbón, Daniel
This study aims to explore shape variability of the acetabulum during the human adult life span, in relation to sex and age. The human acetabular shape was analysed in 682 os coxae from three different documented skeletal collections from the Iberian Peninsula. Two landmarks and thirty-two sliding semi-landmarks were used for the geometric morphometric procedures and a clock-wise standard was used for orientation. The 180° meridian (6:00) line was positioned over the midpoint of the acetabular notch and 36 reference points in 10° increments along the rim were marked. Data showed that size, sex and age significantly influence acetabular shape variation. Sex differences were significant in individuals younger than 65 years old and were characterised by males exhibiting relatively extended acetabular rim profiles from 10:00 to 1:00, narrower acetabular notches, and reduced acetabular fossae. In addition, three main age-related changes occurred to the acetabular shape in both sexes: outer acetabular profile modification, with extension from 10:00 to 1:00 and reduction from 7:00 to 9:00, acetabular notch narrowing, and acetabular fossa reduction. The age-related changes that were observed are shared by both sexes and seem to be related to bone production associated with age. Specifically, age appears to affect the entire border of the lunate surface: the acetabular rim, both acetabular horns, and the outer edge of the acetabular fossa. Furthermore, shape data confirmed the clover-leaf shape of the acetabular fossa in both males and females. These results improve our understanding of acetabular shape, and assist in refining age-estimation methods and enhancing hip surgery and rehabilitation.
Sirka, Aurimas; Clauss, Martin; Tarasevicius, Sarunas; Wingstrand, Hans; Stucinskas, Justinas; Robertsson, Otto; Emil Ochsner, Peter; Ilchmann, Thomas
Background and purpose — The original Müller acetabular reinforcement ring (ARR) shows favorable medium-term results for acetabular reconstruction in total hip arthroplasty, where it is used when the acetabular bone stock is deficient. However, there are no data regarding long-term survival of the device. We therefore investigated long-term survival and analyzed radiological modes of failure. Patients and methods — Between 1984 and 2002, 321 consecutive primary arthroplasties using an ARR were performed in 291 patients. The mean follow-up time was 11 (0–25) years, and 24 hips were lost to follow-up. For survival analysis, we investigated 321 hips and the end of the follow-up was the date of revision, date of death, or the last patient contact date with implant still in situ. Radiological assessment was performed for 160 hips with a minimum of 10 years of follow-up and with radiographs of sufficient quality. It included evaluation of osteolysis, migration, and loosening. Results — 12 ARR THAs were revised: 1 isolated ARR revision for aseptic loosening, 4 revisions of the ARR and the stem for aseptic loosening, 6 for infection, and 1 for recurrent dislocation. The cumulative revision rate for all components, for any reason, at 20 years was 15% (95% CI: 10–22), while for the ARR only it was 7% (95% CI: 4–12) for any reason and 3.4% (95% CI: 1–9) for aseptic loosening. 21 (13%) of 160 ARR THAs examined had radiological changes: 7 had osteolysis but were not loose, and 14 were radiologically loose but were not painful and not revised. Interpretation — Our data suggest that the long-term survival of the ARR is excellent. PMID:26471881
Subchondral insufficiency fracture (SIF) of the femoral head occurs in the elderly and recipients of organ transplantation. Osteoporosis and deficient lateral coverage of the acetabulum are known risk factors for SIF. There has been no study about relation between spinopelvic alignment and anterior acetabular coverage with SIF. We therefore asked whether a decrease of lumbar lordosis and a deficiency in the anterior acetabular coverage are risk factors. We investigated 37 patients with SIF. There were 33 women and 4 men, and their mean age was 71.5 years (59-85 years). These 37 patients were matched with 37 controls for gender, age, height, weight, body mass index and bone mineral density. We compared the lumbar lordosis, pelvic incidence, pelvic tilt, sacral slope, acetabular index, acetabular roof angle, acetabular head index, anterior center-edge angle and lateral center-edge angle. Lumbar lordosis, pelvic tilt, sacral slope, lateral center edge angle, anterior center edge angle, acetabular index and acetabular head index were significantly different between SIF group and control group. Lumbar lordosis (OR = 1.11), lateral center edge angle (OR = 1.30) and anterior center edge angle (OR = 1.27) had significant associations in multivariate analysis. Decreased lumbar lordosis and deficient anterior coverage of the acetabulum are risk factors for SIF as well as decreased lateral coverage of the acetabulum. PMID:27550496
van Egmond, Nienke; De Kam, Daniel C. J.; Gardeniers, Jean W. M.
Background Loosening of acetabular components often leads to bony defects. Management of extensive acetabular bone loss in hip revision arthroplasty can be a tremendous challenge. Questions/purposes We asked whether a reconstruction with impacted bone grafts will provide a durable and pain-free function in extensive acetabular defects. We specifically determined the (1) survival rates with the end point of revision for any reason, aseptic revision, and radiographic loosening; (2) visual analog scale (VAS) pain score, Harris hip score (HHS), and the Oxford Hip Questionnaire score (OHQS); (3) number of repeat revisions; (4) complications; and (5) radiographic loosening, wear, and radiolucencies. Patients and Methods We retrospectively followed 25 patients (27 hips) with extensive acetabular defects. No patient was lost to followup. Two patients died during followup. Minimum followup was 3 years (mean, 8.8 years; range, 3–14.1 years). Results Three patients (three hips) underwent repeat revision surgery and another two patients (two hips) had radiographically loose hips. The 10-year survival rate was 88% (95% confidence interval, 74.2%–100%) with the end point acetabular revision for any reason and 95% (95% confidence interval, 86.0%–100%) with the end point acetabular revision for aseptic loosening. The mean HHSs were 55 points before surgery and 72 points postoperatively. Conclusions Acetabular reconstruction with impaction bone grafting and a cemented cup is a reliable technique with a 10-year survival rate of 88% in patients with extensive acetabular deficiencies. Level of Evidence Level IV, case series. See the Guidelines for Authors for a complete description of levels of evidence. PMID:20931308
Kang, H. K.; Park, S. B.; Kim, S. H.; Kim, C. H.
The effects of stocking density on the performance, egg quality, leukocyte concentration, blood biochemistry, corticosterone levels, bone mineral density, and noxious gas emission of laying hens were investigated. Eight hundred 34-week-old Hy-Line Brown laying hens (Gallus gallus domesticus) were randomly assigned to one of 4 treatments, each of which was replicated 4 times. Four stocking densities, including 5, 6, 7, and 10 birds/m2, were compared. A commercial-type basal diet was formulated to meet or exceed nutrient recommendations for laying hens from the National Research Council. The diet was fed to the hens ad libitum for 8 wk. Results indicated that hen-day egg production, egg mass, and feed intake were less for (P < 0.01) 10 birds/m2 stock density than other stock densities. Production rate of floor and broken eggs and eggshell strength were greater (P < 0.01) for 10 birds/m2 stock density than other stock densities. There were no significant differences in the level of leukocytes among densities. However, heterophils and the H/L ratio were greater (P < 0.01) for 10 birds/m2 than in stock density of 6 or 7 birds/m2. Serum corticosterone was greater (P < 0.01) 10 birds/m2 than stock density than other stock densities. Litter moisture and gas emission (CO2 and NH3) were greater (P < 0.01) for 10 birds/m2 than stock density than 6 and 7 birds/m2 stock density. Bone mineral content was not influenced by increasing stock density. However, bone mineral density was less (P < 0.05) for 10 m2 stock density than other stock densities. These results indicate that increasing the density beyond 5 birds/m2 elicits some negative effects on laying performance of Hy-Line brown laying hens. PMID:27578881
Kang, H K; Park, S B; Kim, S H; Kim, C H
The effects of stocking density on the performance, egg quality, leukocyte concentration, blood biochemistry, corticosterone levels, bone mineral density, and noxious gas emission of laying hens were investigated. Eight hundred 34-week-old Hy-Line Brown laying hens (Gallus gallus domesticus) were randomly assigned to one of 4 treatments, each of which was replicated 4 times. Four stocking densities, including 5, 6, 7, and 10 birds/m(2), were compared. A commercial-type basal diet was formulated to meet or exceed nutrient recommendations for laying hens from the National Research Council. The diet was fed to the hens ad libitum for 8 wk. Results indicated that hen-day egg production, egg mass, and feed intake were less for (P < 0.01) 10 birds/m(2) stock density than other stock densities. Production rate of floor and broken eggs and eggshell strength were greater (P < 0.01) for 10 birds/m(2) stock density than other stock densities. There were no significant differences in the level of leukocytes among densities. However, heterophils and the H/L ratio were greater (P < 0.01) for 10 birds/m(2) than in stock density of 6 or 7 birds/m(2) Serum corticosterone was greater (P < 0.01) 10 birds/m(2) than stock density than other stock densities. Litter moisture and gas emission (CO2 and NH3) were greater (P < 0.01) for 10 birds/m(2) than stock density than 6 and 7 birds/m(2) stock density. Bone mineral content was not influenced by increasing stock density. However, bone mineral density was less (P < 0.05) for 10 m(2) stock density than other stock densities. These results indicate that increasing the density beyond 5 birds/m(2) elicits some negative effects on laying performance of Hy-Line brown laying hens.
Tai, Ching-Lung; Lee, Po-Yi; Hsieh, Pang-Hsing
Background Acetabular reinforcement devices (ARDs) are frequently used as load-sharing devices to allow allograft incorporation in revision hip arthroplasty with massive acetabular bone loss. The key to a successful reconstruction is robust fixation of the device to the host acetabulum. Interlocking fixation is expected to improve the initial stability of the postoperative construct. However, all commercially available ARDs are designed with non-locking fixation. This study investigates the efficacy of standard ARDs modified with locking screw mechanisms for improving stability in acetabular reconstruction. Methods Three types of ARDs were examined to evaluate the postoperative compression and angular stability: i) standard commercial ARDs, ii) standard ARDs modified with monoaxial and iii) standard ARDs modified with polyaxial locking screw mechanisms. All ARDs were implanted into osteomized synthetic pelvis with pelvic discontinuity. Axial compression and torsion tests were then performed using a servohydraulic material testing machine that measured load (angle) versus displacement (torque). Initial stability was compared among the groups. Results Equipping ARDs with interlocking mechanisms effectively improved the initial stability at the device/bone interface compared to standard non-locked ARDs. In both compression and torsion experiments, the monoaxial interlocking construct demonstrated the highest construct stiffness (672.6 ± 84.1 N/mm in compression and 13.3 ± 1.0 N·m/degree in torsion), whereas the non-locked construct had the lowest construct stiffness (381.4 ± 117.2 N/mm in compression and 6.9 ± 2.1 N·m/degree in torsion) (P < 0.05). Conclusions Our study demonstrates the potential benefit of adding a locking mechanism to an ARD. Polyaxial ARDs provide the surgeon with more flexibility in placing the screws at the cost of reduced mechanical performance. This in vitro study provides a preliminary evaluation of biomechanical performance for ARDs
Phillips, A T M; Pankaj; Usmani, A S; Howie, C R
The study uses idealized two-dimensional finite element models to examine the behaviour of the acetabular construct following revision hip arthroplasty, carried out using the Slooff-Ling impaction grafting technique. The behaviour of bone graft was considered in detail, with non-linear elasticity and non-associated plasticity being adopted. Load was applied to the acetabular construct through a femoral head using smooth sliding surfaces. In particular, four models were subjected to two idealized cyclic load cases to investigate the effect of acetabular cup size on the short-term stability of the acetabular construct. The study suggests that benefits may be gained by using the largest practical size of acetabular cup.
Silva, Paulo; de Oliveira, Leandro Alves; Coelho, Danilo Lopes; do Amaral, Rogério Andrade; Rebello, Percival Rosa; de Moraes, Frederico Barra
To describe a new procedure of total hip replacement in patient with severe developmental dysplasia of the left hip, using technique of acetabular reconstruction with autogenous bone grafts and subtrochanteric shortening femoral osteotomy. Total hip replacement done in January of 2003. The Eftekhar's classification was used and included type D, neglected dislocations. Bone graft incorporated in acetabular shelf and femoral osteotomy. Our contribution is the use of an Allis plate to better fix acetabular grafts, avoiding loosening, and cerclage around bone graft in femoral osteotomy site, which diminish pseudoarthrosis risk. This technique shows efficiency, allowing immediately resolution for this case with pain and range of motion of hip improvement. It also allows the acetabular dysplasia reconstruction, equalization of the limb length (without elevated risk of neurovascular lesion) and repairs the normal hip biomechanics due to the correction of the hip's center of rotation. PMID:26229775
Alam, Imranul; Koller, Daniel L.; Cañete, Toni; Blázquez, Gloria; Mont-Cardona, Carme; López-Aumatell, Regina; Martínez-Membrives, Esther; Díaz-Morán, Sira; Tobeña, Adolf; Fernández-Teruel, Alberto; Stridh, Pernilla; Diez, Margarita; Olsson, Tomas; Johannesson, Martina; Baud, Amelie; Econs, Michael J.; Foroud, Tatiana
We previously demonstrated that skeletal structure and strength phenotypes vary considerably in heterogeneous stock (HS) rats. These phenotypes were found to be strongly heritable, suggesting that the HS rat model represents a unique genetic resource for dissecting the complex genetic etiology underlying bone fragility. The purpose of this study was to identify and localize genes associated with bone structure and strength phenotypes using 1524 adult male and female HS rats between 17 to 20 weeks of age. Structure measures included femur length, neck width, head width; femur and lumbar spine (L3-5) areas obtained by DXA; and cross-sectional areas (CSA) at the midshaft, distal femur and femoral neck, and the 5th lumbar vertebra measured by CT. In addition, measures of strength of the whole femur and femoral neck were obtained. Approximately 70,000 polymorphic SNPs distributed throughout the rat genome were selected for genotyping, with a mean linkage disequilibrium coefficient between neighboring SNPs of 0.95. Haplotypes were estimated across the entire genome for each rat using a multipoint haplotype reconstruction method, which calculates the probability of descent at each locus from each of the 8 HS founder strains. The haplotypes were then tested for association with each structure and strength phenotype via a mixed model with covariate adjustment. We identified quantitative trait loci (QTLs) for structure phenotypes on chromosomes 3, 8, 10, 12, 17 and 20, and QTLs for strength phenotypes on chromosomes 5, 10 and 11 that met a conservative genome-wide empiric significance threshold (FDR=5%; P<3 × 10−6). Importantly, most QTLs were localized to very narrow genomic regions (as small as 0.3Mb and up to 3 Mb), each harboring a small set of candidate genes, both novel and previously shown to have roles in skeletal development and homeostasis. PMID:26297441
Mai, J G; Gu, C; Lin, X Z; Li, T; Huang, W Q; Wang, H; Tan, X Y; Lin, H; Wang, Y M; Yang, Y Q; Jin, D D; Fan, S C
Objective: To investigate reduction and fixation of complex acetabular fractures using three-dimensional (3D) printing technique and personalized acetabular wing-plate via lateral-rectus approach. Methods: From March to July 2016, 8 patients with complex acetabular fractures were surgically managed through 3D printing personalized acetabular wing-plate via lateral-rectus approach at Department of Orthopedics, the Third Affiliated Hospital of Southern Medical University. There were 4 male patients and 4 female patients, with an average age of 57 years (ranging from 31 to 76 years). According to Letournel-Judet classification, there were 2 anterior+ posterior hemitransverse fractures and 6 both-column fractures, without posterior wall fracture or contralateral pelvic fracture. The CT data files of acetabular fracture were imported into the computer and 3D printing technique was used to print the fractures models after reduction by digital orthopedic technique. The acetabular wing-plate was designed and printed with titanium. All fractures were treated via the lateral-rectus approach in a horizontal position after general anesthesia. The anterior column and the quadrilateral surface fractures were fixed by 3D printing personalized acetabular wing-plate, and the posterior column fractures were reduction and fixed by antegrade lag screws under direct vision. Results: All the 8 cases underwent the operation successfully. Postoperative X-ray and CT examination showed excellent or good reduction of anterior and posterior column, without any operation complications. Only 1 case with 75 years old was found screw loosening in the pubic bone with osteoporosis after 1 month's follow-up, who didn't accept any treatment because the patient didn't feel discomfort. According to the Matta radiological evaluation, the reduction of the acetabular fracture was rated as excellent in 3 cases, good in 4 cases and fair in 1 case. All patients were followed up for 3 to 6 months and all
Issack, Paul S
➤ Over the past decade, porous tantalum has emerged as a powerful tool for reconstruction of the failed acetabular component.➤ The increased porosity, high coefficient of friction, and favorable elastic modulus of porous tantalum compared with traditional titanium mesh or cobalt chromium acetabular components allow for greater bone ingrowth potential, implant stability, and host bone preservation, respectively, in porous tantalum shells.➤ Several studies have confirmed the excellent early and midterm results of porous tantalum reconstruction for revision hip arthroplasty.➤ Depending on the degree of bone loss, excellent results have been achieved with modular or revision porous tantalum shells, tantalum shells with tantalum augments, and cup-cage constructs.➤ These implants and techniques are greatly changing the approach to acetabular revision surgery and are providing constructs with greater stability and more physiologic biomechanical properties than those achieved through the use of traditional reconstructive methods.
Meneghini, R Michael; Hull, Jason R; Russo, Glenn S; Lieberman, Jay R; Jiranek, William A
In revision total hip arthroplasty (THA), consensus is lacking regarding the optimal method for reconstruction of the most severe acetabular defects. Porous tantalum (TM) buttress augments were designed for the most severe postero-superior defects. The purpose of this study was to report the results of a consecutive series of acetabular reconstructions utilizing TM buttress augments. Eight complex acetabular reconstructions utilizing a TM buttress augment were performed at two centers. All were Paprosky 3A or Paprosky 3B bone loss classification, with severe superior and posterior column deficiency where wedge augments were insufficient for mechanical support. The acetabular cup sizes ranged from 64-78, and a buttress shim was used in 7 of 8 cases. Clinical and radiographic follow-up averaged 16.5 months (range, 10-28) and no cases were lost to follow-up. There were no cases of clinical or radiographic loosening, and no case had required reoperation or revision. All patients except one were ambulating with either no assist device or a single cane at final follow-up. There was one complication of an iliac wing fracture noted incidentally on postoperative x-rays in the lone patient in whom a buttress shim was not used. At short-term follow-up, TM acetabular buttress augments appear to effectively substitute for the use of structural allografts or cages, which would otherwise be used in this challenging setting. The potential for biologic fixation is promising for the durability of these reconstructions; however, longer-term follow-up is required for full evaluation.
Potratz, Carsten; Kluess, Daniel; Ewald, Hartmut; van Rienen, Ursula
In this paper, we present a new approach for the enhancement of the bone proliferation rate by electrostimulation in the acetabular region. Based on the complex tissue structure in this area, the electric field distributions were computed by numerical means using a model based on high-resolution computed tomography scans of the acetabular area. This results in a complex, nonlinear, and discrete optimization problem. Therefore, an adapted algorithm was developed to reduce the computational effort in the order of several magnitudes. We divided the procedure into two stages: data extraction and a subsequent optimization process. The used optimization algorithm utilizes an evolutionary concept and a multidimensional definition of optimality for different, partly contradictive objective functions. Finally, we present first optimization results for different stimulation situations.
Dickinson, A S; Taylor, A C; Browne, M
Acetabular cup loosening is a late failure mode of total hip replacements, and peri-prosthetic bone deterioration may promote earlier failure. Preservation of supporting bone quality is a goal for implant design and materials selection, to avoid stress shielding and bone resorption. Advanced polymer composite materials have closer stiffness to bone than metals, ceramics or polymers, and have been hypothesised to promote less adverse bone adaptation. Computer simulations have supported this hypothesis, and the present study aimed to verify this experimentally. A composite hemi-pelvis was implanted with Cobalt Chromium (CoCr), polyethylene (UHMWPE) and MOTIS(®)carbon-fibre-reinforced polyether etherketone (CFR-PEEK) acetabular cups. In each case, load was applied to the implanted pelvis and Digital Image Correlation (DIC) was used for surface strain measurement. The test was repeated for an intact hemi-pelvis. Trends in implanted vs. intact bone principal strains were inspected to assess the average principal strain magnitude change, allowing comparison of the potential bone responses to implantation with the three cups. The CFR-PEEK cup was observed to produce the closest bone strain to the intact hip in the main load path, the superior peri-acetabular cortex (+12% on average, R(2)=0.84), in comparison to CoCr (+40%, R(2)=0.91) and UHWMPE cups (-26%, R(2)=0.94). Clinical observations have indicated that increased periacetabular cortex loading may result in reduced polar cancellous bone loading, leading to longer term losses in periprosthetic bone mineral density. This study provides experimental evidence to verify previous computational studies, indicating that cups produced using materials with stiffness closer to cortical bone recreate physiological cortical bone strains more closely and could, therefore, potentially promote less adverse bone adaptation than stiffer press-fitted implants in current use.
Background and purpose Adequate depth of cement penetration and cement mantle thickness is important for the durability of cemented cups. A flanged cup, as opposed to unflanged, has been suggested to give a more uniform cement mantle and superior cement pressurization, thus improving the depth of cement penetration. This hypothesis was tested experimentally. Materials and methods The same cup design with and without flange (both without cement spacers) was investigated regarding intraacetabular pressure, cement mantle thickness, and depth of cement penetration. With machine control, the cups were inserted into open-pore ceramic acetabular models (10 flanged, 10 unflanged) and into paired cadaver acetabuli (10 flanged, 10 unflanged) with prior pressurization of the cement. Results No differences in intraacetabular pressures during cup insertion were found, but unflanged cups tended to migrate more towards the acetabular pole. Flanged cups resulted in thicker cement mantles because of less bottoming out, whereas no differences in cement penetration into the bone were observed. Interpretation Flanged cups do not generate higher cementation pressure or better cement penetration than unflanged cups. A possible advantage of the flange, however, may be to protect the cup from bottoming out, and there is possibly better closure of the periphery around the cup, sealing off the cement-bone interface. PMID:20860522
Li, Huiwu; Wang, Liao; Mao, Yuanqing; Wang, You; Dai, Kerong; Zhu, Zhenan
This study details a method using rapid prototyping (RP) technique to assist in acetabular revision with complex bone defects. Hemi-pelvic RP models were built among 25 patients with complex acetabular bone defects. Each patient was scheduled to undergo revision using either commercially available or customized cages based on individualized RP models. Average follow-up was 4.4 years (range, 1 to 9 years). The average Harris hip score was 36.1 (range, 20 to 58) preoperatively and reached an average of 82.6 (range, 60-96) at the last follow-up. No mechanical failure or loosening was observed. One patient experienced hip dislocation 4 days postoperatively. The resultant findings of this study merit consideration of RP as a helpful clinical complement for dealing with some complex bone defect of acetabulum.
Macdonald, Duncan; Gupta, Sanjay; Ohly, Nicholas E; Patil, Sanjeev; Meek, R; Mohammed, Aslam
Acetabular introducers have a built-in inclination of 45 degrees to the handle shaft. With patients in the lateral position, surgeons aim to align the introducer shaft vertical to the floor to implant the acetabulum at 45 degrees. We aimed to determine if a bulls-eye spirit level attached to an introducer improved the accuracy of implantation. A small circular bulls-eye spirit level was attached to the handle of an acetabular introducer. A saw bone hemipelvis was fixed to a horizontal, flat surface. A cement substitute was placed in the acetabulum and subjects were asked to implant a polyethylene cup, aiming to obtain an angle of inclination of 45 degrees. Two attempts were made with the spirit level masked and two with it unmasked. The distance of the air bubble from the spirit level's center was recorded by a single assessor. The angle of inclination of the acetabular component was then calculated. Subjects included both orthopedic consultants and trainees. Twenty-five subjects completed the study. Accuracy of acetabular implantation when using the unmasked spirit level improved significantly in all grades of surgeon. With the spirit level masked, 12 out of 50 attempts were accurate at 45 degrees inclination; 11 out of 50 attempts were "open," with greater than 45 degrees of inclination, and 27 were "closed," with less than 45 degrees. With the spirit level visible, all subjects achieved an inclination angle of exactly 45 degrees. A simple device attached to the handle of an acetabular introducer can significantly improve the accuracy of implantation of a cemented cup into a saw bone pelvis in the lateral position.
Marongiu, Giuseppe; Capone, Antonio
Summary Bisphosphonates have been commonly used in the treatment of osteoporosis, demonstrating its efficacy in fracture risk reduction. However, even if are generally safe and well tolerated, concerns have emerged about atypical fractures related to its prolonged use. Although atypical femoral fracture are more common, case reports demonstrated that even other skeletal areas can be involved by unusual pattern of fracture. We report a atypical acetabular periprosthetic fracture in a 83-year-old female patient after prolonged alendronate treatment for osteoporosis and isolated acetabular revision surgery. The patient underwent to clinical, bioumoral and radiological evaluation and all the history cases were fully reported. We believe this periprosthetic fracture, according to the available data, may have similar underlying pathology to atypical femoral fractures. Awareness of symptoms, in addition to a regular radiographic survey may facilitate early diagnosis and possible prevention of spontaneous periprosthetic fractures, in patients receiving bisphosphonate therapy beyond 5 years. The treatment of this atypical periprosthetic fracture should include both surgical than pharmacological therapy to obtained bone healing. PMID:28228784
Molière, S; Dosch, J-C; Bierry, G
Pelvic ring fractures when caused by trauma, either violent or in demineralized bone, generally consist of injuries in both the anterior (pubic symphysis and rami) and posterior (iliac wing, sacrum, sacroiliac joint) portions. Injury classifications are based on injury mechanism and pelvic stability, and are used to determine treatment. Acetabular fractures, associated or not to pelvic ring disruption, are classified on the basis of fracture line, into elementary fractures of the acetabular walls, columns and roof, and into complex fractures. Fractures of the proximal end of the femur occur often on demineralized bone following low-energy trauma. The fractures are categorized by anatomic location (neck, trochanter and subtrochanteric region) and degree of displacement. These variables determine the risk of osteonecrosis of the femoral head, which is the main complication of such fractures.
Hendrix, Stephen L.; Mologne, Timothy S.; Peterson, Drew A.; Holley, Keith A.
To evaluate the efficacy of a commercially available acetabular positioning device, we performed a prospective evaluation of 40 consecutive patients undergoing primary total hip arthroplasty. All surgery was performed by the same surgeon, in the same operating room, and on the same operating table. The acetabular positioning device was designed to place the component in 45° of abduction. At 6 weeks, all radiographs were evaluated by 3 investigators not involved with the surgery. Each radiograph was evaluated by each reviewer on 3 separate occasions, blinded to the findings of the other reviewer to assess interobserver and intraobserver variability. The mean cup abduction angle was 42.1°, with a range from 23° to 57° (SD 8.3°). Intraobserver and interobserver variability were 0.2 and 0.3°, respectively. The findings of this study demonstrate a wide variability in acetabular cup placement in primary total hip arthroplasty. We believe this is due to movement of the pelvis, which may occur during preparation, draping, and retracting during surgery. We feel surgeons should not rely solely on positioning devices when implanting the acetabular component in total hip arthroplasty. Identification of bone landmarks and determination of superolateral implant coverage noted on preoperative templating is advocated to improve the precision of component position. PMID:18751812
Wieding, Jan; Souffrant, Robert; Fritsche, Andreas; Mittelmeier, Wolfram; Bader, Rainer
bone stock and can be used for further investigations.
Narváez, J A; Narváez, J; Rodríguez-Mijarro, M; Quintero, J C
The presence of intraosseous gas most commonly occurs in osteomyelitis, vacuum phenomenon, and postsurgery or posttraumatic states. Several cases of subchondral gas-filled lesions, called pneumatocysts, have also been described in the sacroiliac joint and clavicle, none of them with intralesional air-fluid level. These pneumatocysts are innocuous lesions of uncertain origin. We describe one case of acetabular pneumatocyst containing air-fluid level in a 62-year-old man with long-standing ankylosing spondylitis involving hip joint. To our knowledge, this is the first reported case of a pneumatocyst in an acetabular location containing air-fluid level.
Fox, Ciara M; Bergin, Karen M; Kelly, Gabrielle E; McCoy, Gerry F; Ryan, Anthony G; Quinlan, John F
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.
Wang, J-Y; Heaton-Adegbile, P; New, A; Hussell, J G; Tong, J
Damage development in cemented acetabular replacements has been studied in bovine pelvic bones under long-term physiological loading conditions, including normal walking, stair climbing and a combined block loading with representative routine activities. The physiological loading conditions were achieved using a specially designed hip simulator for fixation endurance testing. Damage was detected and monitored using micro-CT scanning at regular intervals of the experiments, and verified by microscopic studies post testing. The results show that debonding at the bone-cement interface defined the failure of cement fixation in all cases, and debondings initiated near the dome of the acetabulum in the superior-posterior quadrant, consistent with the high-stress region identified from the finite element analysis of implanted acetabular models Zant, N.P., Heaton-Adegbile, P., Hussell, J.G., Tong, J., 2008b. In-vitro fatigue failure of cemented acetabular replacements-a hip simulator study. Journal of Biomechanical Engineering, Transactions of the ASME, 130, 021019-1-9]; [Tong, J., Zant, N.P., Wang, J-Y., Heaton-Adegbile, P., Hussell, J.G., 2008. Fatigue in cemented acetabulum. International Journal of Fatigue, 30(8), 1366-1375].
Benazzi, S; Maestri, C; Parisini, S; Vecchi, F; Gruppioni, G
Determining sex from skeletal remains is one of the most important steps in archaeological and forensic anthropology. The present study considers the diagnostic value of the acetabulum based on its planar image and related metric data. For this purpose, 83 adult os coxae of known age were examined. Digital photos of the acetabular area were taken, with each bone in a standardized orientation. Technical drawing software was used to trace the acetabular rim and to measure the related dimensions (area, perimeter, longitudinal and transverse maximum width). The measurements were subjected to SPSS discriminant and classification function analysis. There were significant differences (p
Daines, Brian K; Dennis, Douglas A
Correct acetabular cup position is critical to successful total hip replacement. Unfortunately, malposition of acetabular cups is common and leads to increased rates of dislocation, wear, and ion toxicity. Despite the popularity of Lewinnek's safe zone, the exact target of acetabular abduction and version remains elusive. Differences in functional pelvic position, surgical approach, and femoral anteversion affect the optimal cup position for individual patients. Surgeons need to be aware of pelvic position changes from the supine to lateral decubitus position.
Meralgia paresthetica consists of pain and dysesthesia in the anterolateral thigh. Etiology is divided into spontaneous and iatrogenic causes. To my knowledge this has never been attributed to femoral acetabular impingement. This case highlights the presence of lateral femoral cutaneous neuropathy in the setting of femoral acetabular impingement syndrome thus raising the possibility of an association. Keywords Femoral acetabular impingement; Lateral femoral cutaneous nerve; Dysesthesia; Nerve conduction studies PMID:22043261
Birrell, F; Silman, A; Croft, P; Cooper, C; Hosie, G; Macfarlane, G
Design: Cross sectional analysis of a prospective cohort. Setting: 35 general practices across the UK. Subjects: 195 patients (63 male, 132 female) aged 40 years and over presenting with a new episode of hip pain Results: The prevalence of acetabular dysplasia in this study of new presenters with hip pain was high (32%). There was no significant relationship between acetabular dysplasia and radiographic OA overall. Conclusions: The high prevalence of acetabular dysplasia across all grades of OA severity suggests that dysplasia itself may be an important cause of hip pain ("symptomatic adult acetabular dysplasia"). PMID:12634238
Yoon, Jung-Ro; Yu, Jung Jin; Seo, Hyo-Sung
Purpose To evaluate the usefulness of navigated acetabular cup fixation for total hip arthroplasty in patients with acetabular deformity or revision total hip arthroplasty. Materials and Methods This study enrolled 28 patients with at least 12 months' follow-up. The safe zone of the acetabular cup was defined as 40°±10°in inclination and 15°±10°in anteversion. The authors used the navigation and radiographic data to determine whether the acetabular cup was located within the safe zone or not. To evaluate the clinical outcomes, preoperative and last follow-up Harris hip scores were checked, and the occurrence of complications was evaluated. Results According to the navigation data, the mean inclination and anteversion were 38.5°±4.7°(range, 32°-50°) and 16.6°±4.0°(range, 8°-23°), respectively. According to the radiographic data the mean inclination and anteversion were 40.5°±4.6°(range, 32°-50°) and 19.4°±4.2°(range, 8°-25°), respectively. In both cases, all values were within the safe zone. Harris hip score was improved in all patients from preoperative 52.3±14.4 points (range, 29-87 points) to 88.0±9.0 points (range, 65-99 points) at the last follow-up. There was no dislocation or loosening of both cases. Conclusion Navigated acetabular cup fixation is a useful technique for total hip arthroplasty in patients with acetabular deformity or revision total hip arthroplasty because it prevents the malposition and related complications. PMID:27536573
Bicanic, Goran; Barbaric, Katarina; Bohacek, Ivan; Aljinovic, Ana; Delimar, Domagoj
Adult patients with developmental dysplasia of the hip develop secondary osteoarthritis and eventually end up with total hip arthroplasty (THA) at younger age. Because of altered anatomy of dysplastic hips, THA in these patients represents technically demanding procedure. Distorted anatomy of the acetabulum and proximal femur together with conjoined leg length discrepancy present major challenges during performing THA in patients with developmental dysplasia of the hip. In addition, most patients are at younger age, therefore, soft tissue balance is of great importance (especially the need to preserve the continuity of abductors) to maximise postoperative functional result. In this paper we present a variety of surgical techniques available for THA in dysplastic hips, their advantages and disadvantages. For acetabular reconstruction following techniques are described: Standard metal augments (prefabricated), Custom made acetabular augments (3D printing), Roof reconstruction with vascularized fibula, Roof reconstruction with pedicled iliac graft, Roof reconstruction with autologous bone graft, Roof reconstruction with homologous bone graft, Roof reconstruction with auto/homologous spongious bone, Reinforcement ring with the hook in combination with autologous graft augmentation, Cranial positioning of the acetabulum, Medial protrusion technique (cotyloplasty) with chisel, Medial protrusion technique (cotyloplasty) with reaming, Cotyloplasty without spongioplasty. For femoral reconstruction following techniques were described: Distraction with external fixator, Femoral shortening through a modified lateral approach, Transtrochanteric osteotomies, Paavilainen osteotomy, Lesser trochanter osteotomy, Double-chevron osteotomy, Subtrochanteric osteotomies, Diaphyseal osteotomies, Distal femoral osteotomies. At the end we present author’s treatment method of choice: for acetabulum we perform cotyloplasty leaving only paper-thin medial wall, which we break during
Rady, Ahmad Emad; Asal, Mohammed Kamal; Bassiony, Ayman Abdelaziz
Recurrent dislocation after total hip arthroplasty is a disabling complication that can be difficult to treat. We evaluated the early clinical and radiographic outcome associated with the use of a constrained acetabular component for instability in total hip arthroplasty. Fifteen patients underwent either primary or revision total hip arthroplasty with a cementless constrained acetabular component for different indications. The mean patient age at surgery was 57.4 years and the mean clinical and radiological follow-up period was 26.4 months. Clinical assessment was performed by the Harris hip score and at the latest follow up patients reported outcome using the Oxford hip score questionnaire. All radiographs were evaluated for evidence of loosening. Only one patient experienced redislocation with the constrained prosthesis. The average Harris hip score increased from a preoperative mean of 22 (range, 16 - 36) to a postoperative mean of 85 (range, 66-94). Preoperatively, the mean Oxford Hip Score was 48.6, which decreased to 20.5 at the final examination. All but one of the 15 hips had a well-fixed, stable cup. Femoral component stability with bone ingrowth was achieved in 10 cases. A constrained acetabular component is an effective option for the treatment of hip instability in primary and revision arthroplasty in those at high risk of dislocation. The potential for aseptic loosening requires evaluation by long term studies.
Andreani, Lorenzo; Bonicoli, Enrico; Niccolai, Francesco; Lisanti, Michele
Acetabular cup loosening is associated with pain, reduced function, and instability of the implant. If such event happens while the femoral implant is in a satisfactory position and is well fixed to the bone, isolated acetabular revision surgery is indicated. The aim of this single-center retrospective study was to evaluate the clinical and radiological results over the medium term (12-month follow-up mean 36, max 60) of isolated acetabular revisions surgery using a porous hemispheric revision shell matched with a cemented all-poly cup and large diameter femoral head (>32). 33 patients were enrolled. We collect any relevant data from the clinical board. Routine clinical and radiographic examinations were performed preoperatively; the postoperative follow-up was made at 1, 3, and 6 months and yearly thereafter. At the last available follow-up, we report satisfactory improvement of functional scores in all the patients; 2 patients (6.1%) showed thigh pain and only 4 hips (12.11%) presented mild groin pain; all the femoral components are well fixed and there were no potential or pending rerevisions. With bias due to the follow-up and to the retrospective design of the study, we report clinical, functional, and radiological satisfactory results. PMID:25610894
Ghosh, Rajesh; Pratihar, Dilip Kumar; Gupta, Sanjay
Aseptic loosening of the acetabular component (hemispherical socket of the pelvic bone) has been mainly attributed to bone resorption and excessive generation of wear particle debris. The aim of this study was to determine optimal design parameters for the acetabular component that would minimize bone resorption and volumetric wear. Three-dimensional finite element models of intact and implanted pelvises were developed using data from computed tomography scans. A multi-objective optimization problem was formulated and solved using a genetic algorithm. A combination of suitable implant material and corresponding set of optimal thicknesses of the component was obtained from the Pareto-optimal front of solutions. The ultra-high-molecular-weight polyethylene (UHMWPE) component generated considerably greater volumetric wear but lower bone density loss compared to carbon-fibre reinforced polyetheretherketone (CFR-PEEK) and ceramic. CFR-PEEK was located in the range between ceramic and UHMWPE. Although ceramic appeared to be a viable alternative to cobalt-chromium-molybdenum alloy, CFR-PEEK seems to be the most promising alternative material.
Smith, S L; Ash, H E; Unsworth, A
A novel design of polyurethane compliant layer acetabular cup has been developed through a series of friction, creep and wear tests. Friction tests were initially conducted on ABG standard form, polyurethane acetabular cups and an ABG standard form, UHMWPE acetabular cup for comparison. The polyurethane cups showed lower friction than the UHMWPE cup with maximum friction factors between 0. 008 and 0.02 compared with 0.035 for the UHMWPE cup. This indicated that, in the polyurethane cups, more of the load across the joint was carried by the fluid entrapped in the joint space rather than with asperity contact, compared with the UHMWPE cup. The inherent compliance of the polyurethane is used to promote elasto-hydrodynamic lubrication. However, this compliance raised concerns over excessive creep, which may in turn adversely affect tribological performance. Therefore, creep tests were undertaken on the ABG standard form, polyurethane acetabular cups followed by further friction tests. Small amounts of creep occurred in the polyurethane cups at ambient temperature, which reduced the friction slightly (maximum friction factors of 0.009) due to increased conformity between the head and the cup. However, at 37 degrees C, greater creep occurred causing pinching of the femoral head by the acetabular cup resulting in lubricant starvation and higher friction (maximum friction factors of 0.035). The design of the polyurethane cups was subsequently modified to incorporate a flared rim to eliminate the possibility of fluid starvation through pinching. Creep in polyurethane acetabular cups is also affected by the method of fixation of the cups, due to the conformity with and the stiffness of the cup backing. Hence, a one-million-cycle wear test was performed on five ABG flared form, polyurethane acetabular cups on the Mk. I Durham Hip Joint Wear Simulator to evaluate the best method of fixation for the polyurethane cups. The smallest amount of penetration, due to creep and wear
Grubor, Predrag; Krupic, Ferid; Biscevic, Mirza; Grubor, Milan
Introduction: Acetabular fractures treatment represents a great controversy, challenge and dilemma for an orthopedic surgeon. Aim: The aim of the paper was to present the results of treatment of 96 acetabular fractures in the Clinic of Traumatology Banja Luka, in the period from 2003 to 2013, as well as to raise awareness regarding the controversy in the methods of choice in treating acetabulum fractures. Material and methods: The series consists of 96 patients, 82 males and 14 females, average age 40.5 years. Traffic trauma was the cause of fractures in 79 patients (85%), and in 17 patients (15%) fractures occurred due to falls from height. Polytrauma was present in 31 patients (32%). According to the classification of Judet and Letournel, representation of acetabular fractures was as follows: posterior wall in 32 patients, posterior column in 28, anterior wall in 4, anterior column in 2, transverse fractures in 8, posterior wall and posterior column in 10, anterior and posterior wall in 6, both- column in 4 and transversal fracture and posterior wall in 2 patients. 14 patients were treated with traction, that is, 6 patients with femoral traction and 8 patients with both lateral and femoral traction. 82 patients (86.4%) were surgically treated. Kocher-Langenbeck approach was applied in the treatment of 78 patients. In two patients from the Kocher-Langenbeck’s approach, the Ollier’s approach had to be applied as well. Two acetabular were primarily treated with Ollier’s approach. Extended Smith- Peterson’s approach was applied 4 times, and Emile Letournel’s (ilioinguinal) approach 14 times. Results: Functional outcome (after follow-up of 18 months), according to the Harris hip score of surgical treatment in 82 patients, was as follows: good 46 (56%), satisfactory 32 (39%) and poor 4 (5%). Results of acetabulum fractures treated with traction were: good 8 (57%), satisfactory 4 (28%) and poor 2 (15%). According to the Brook’s classification of heterotopic
Zant, Nikolaus P.; Wong, Charles K.Y.; Tong, Jie
Although the role of fatigue failure in aseptic loosening of cemented total hip replacements has been extensively studied in femoral components, studies of fatigue failure in cement mantle of acetabular replacements have yet to be reported, despite that the long-term failure rate in the latter is about three times that of femoral components. Part of the reason may be that a complex pelvic bone structure does not land itself readily for a 2D representation as that of a femur. In this work, a simple multilayer model has been developed to reproduce the stress distributions in the cement mantle of an acetabular replacement from a plane strain finite element pelvic bone model. The experimental multilayer model was subjected to cyclic loading up to peak hip contact force during normal walking. Radial fatigue cracks were observed in the vicinity of the maximum tangential and compressive stresses, as predicted by the FE models. Typical fatigue striations were also observed on the fracture surfaces post cyclic testing. The results were examined in the context of retrieval studies, 3D FE analysis and in vitro experimental results using full-sized hemi-pelvic bone models. PMID:19330048
Hanzlik, Josa A; Day, Judd S
While first generation porous coatings have had clinical success, aseptic loosening remains a leading cause of revision. The purpose of this study was to investigate the reasons for revision and to assess the amount of bone ingrowth in retrieved porous tantalum components. In a prospective multicenter retrieval program, 76 porous tantalum acetabular shells, 5 femoral stems, 7 patellas and 36 tibial trays were collected from revision surgeries. A subset of the implants was analyzed for bone ingrowth. The main reason for revision was infection for acetabular shells (1.4 years implantation time) and instability for tibial trays (1.8 years implantation time). Two of the thirty primary surgery acetabular shells and one of the thirty-six primary surgery tibial trays were revised for implant loosening. We observed full depth penetration of bone into the porous tantalum layer for the acetabular shells and femoral stems.
Hanzlik, Josa A.; Day, Judd S.
While first generation porous coatings have had clinical success, aseptic loosening remains a leading cause of revision. The purpose of this study was to investigate the reason for revision and to assess the amount of bone ingrowth in retrieved porous tantalum components. In a prospective multicenter retrieval program, 76 porous tantalum acetabular shells, 5 femoral stems, 7 patellas and 36 tibial trays were collected from revision surgeries. A subset of the implants were analyzed for bone ingrowth. The main reason for revision was infection for acetabular shells (1.4 year implantation time) and instability for tibial trays (1.8 years implantation time). Two of the thirty primary surgery acetabular shells and one of the thirty-six primary surgery tibial trays were revised for implant loosening. We observed full depth penetration of bone into the porous tantalum layer for the acetabular shells and femoral stems. PMID:23518432
Gascoyne, Trevor C; Petrak, Martin J; Turgeon, Thomas R; Bohm, Eric R
Background and purpose We previously reported on a randomized controlled trial (RCT) that examined the effect of adding tobramycin to bone cement after femoral stem migration. The present study examined femoral head penetration into both conventional and highly crosslinked polyethylene acetabular liners in the same group of RCT patients, with a minimum of 5 years of postoperative follow-up. Patients and methods Linear penetration of the femoral head into an X3 (Stryker) crosslinked polyethylene (XLPE) liner was measured in 18 patients (19 hips) using radiostereometric analysis (RSA). Femoral head penetration was also measured in 6 patients (6 hips) with a conventional polyethylene liner (CPE), which served as a control group. Results The median proximal femoral head penetration in the XLPE group after 5.5 years was 0.025 mm with a steady-state penetration rate of 0.001 mm/year between year 1 and year 5. The CPE liner showed a median proximal head penetration of 0.274 mm after 7.2 years, at a rate of 0.037 mm/year. Interpretation The Trident X3 sequentially annealed XLPE liner shows excellent in vivo wear resistance compared to non-crosslinked CPE liners at medium-term implantation. The rate of linear head penetration in the XLPE liners after > 5 years of follow-up was 0.001 mm/year, which is in close agreement with the results of previous studies. PMID:25140986
Pagenkopf, Eric; Grose, Andrew; Partal, George
Acetabular fractures in the elderly population are marked by a high degree of variability in terms of patient and fracture characteristics. Successful outcomes depend on application of highly individualized management principles by experienced teams. Reviewed are indications and outcomes associated with various management options, including closed treatment, open reduction internal fixation, and acute or staged total hip arthroplasty. Proper initial management choices are critical, as early failures and subsequent salvage surgery can be accompanied by significant morbidity. Clinical results after ORIF closely follow the quality of articular reduction and the ability to maintain a congruent reduction of the hip joint. Fracture characteristics predictive of anatomic articular reduction should be treated with ORIF. Fracture characteristics predictive of early post-traumatic arthritis should be treated with simultaneous ORIF and THA. Presented is one referral institution’s treatment algorithm and management approach. PMID:18751831
Callary, Stuart A; Solomon, Lucian B; Holubowycz, Oksana T; Campbell, David G; Munn, Zachary; Howie, Donald W
Background and purpose Wear rates of highly crosslinked polyethylene (XLPE) acetabular components have varied considerably between different published studies. This variation is in part due to the different techniques used to measure wear and to the errors inherent in measuring the relatively low amounts of wear in XLPE bearings. We undertook a scoping review of studies that have examined the in vivo wear of XLPE acetabular components using the most sensitive method available, radiostereometric analysis (RSA). Methods A systematic search of the PubMed, Scopus, and Cochrane databases was performed to identify published studies in which RSA was used to measure wear of XLPE components in primary total hip arthroplasty (THA). Results 18 publications examined 12 primary THA cohorts, comprising only 260 THAs at 2–10 years of follow-up. The mean or median proximal wear rate reported ranged from 0.00 to 0.06 mm/year. However, differences in the manner in which wear was determined made it difficult to compare some studies. Furthermore, differences in RSA methodology between studies, such as the use of supine or standing radiographs and the use of beaded or unbeaded reference segments, may limit future meta-analyses examining the effect of patient and implant variables on wear rates. Interpretation This scoping review confirmed the low wear rates of XLPE in THA, as measured by RSA. We make recommendations to enhance the standardization of reporting of RSA wear results, which will facilitate early identification of poorly performing implants and enable a better understanding of the effects of surgical and patient factors on wear. PMID:25301435
Helmberger, Thomas K.; Hoffmann, Ralf-Thorsten
The typical clinical signs in bone tumours are pain, destruction and destabilization, immobilization, neurologic deficits, and finally functional impairment. Primary malignant bone tumours are a rare entity, accounting for about 0.2% of all malignancies. Also benign primary bone tumours are in total rare and mostly asymptomatic. The most common symptomatic benign bone tumour is osteoid osteoma with an incidence of 1:2000.
Park, Jin young; Kim, Che Keun; Huh, Soon Ho; Kim, Se Jin; Jung, Bo Hyun
Acetabular fractures can be treated with variable method. In this study, acetabular posterior wall fracture was treated with arthroscopic reduction and fixation using cannulated screw. The patient recovered immediately and had a satisfactory outcome. In some case of acetabular fracture could be good indication with additional advantages of joint debridement and loose body removal. So, we report our case with technical note. PMID:27536654
... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Hip joint (hemi-hip) acetabular metal cemented... (hemi-hip) acetabular metal cemented prosthesis. (a) Identification. A hip joint (hemi-hip) acetabular metal cemented prosthesis is a device intended to be implanted to replace a portion of the hip...
Huang, De-Yong; Zhang, Liang; Zhou, Yi-Xin; Zhang, Chun-Yu; Xu, Hui; Huang, Yong
Background: Porous-coated cups have been widely used in acetabular reconstruction after failed treatment of acetabular fractures, and good results have been reported with the use of these cups; however, the durability and functionality of modular trabecular metal (TM) acetabular components in acetabular reconstruction after failed treatment of acetabular fractures remain unclear. This study aimed to examine the radiographic and clinical outcomes associated with the use of modular TM acetabular components for failed treatment of acetabular fractures to assess the durability and functionality of these components in acetabular reconstruction after failed treatment of acetabular fractures. Methods: A total of 41 patients (41 hips) underwent total hip arthroplasty (THA) using modular TM acetabular components for failed treatment of acetabular fractures at our hospital between January 2007 and December 2012. Among these patients, two were lost to follow-up. Therefore, 39 patients (39 hips) were finally included in this study. The Harris hip score before and after the surgery, satisfaction level of the patients, and radiographic results were assessed. Results: The mean Harris hip score increased from 34 (range, 8–52) before surgery to 91 (range, 22–100) at the latest follow-up examination (P < 0.001). The results were excellent for 28 hips, good for six, fair for three, and poor for two. Among the 39 patients, 25 (64%) and 10 (26%) were very satisfied and somewhat satisfied, respectively. All cups were found to be fully incorporated, and no evidence of cup migration or periacetabular osteolysis was noted. Conclusions: Despite the technically demanding nature of the procedure, THA using modular TM acetabular components showed good durability and functionality and may be an effective reconstruction option for failed treatment of acetabular fractures. PMID:27064033
Xue, Zichao; Qin, Hui; Ding, Haoliang; An, Zhiquan
Background There is no single approach that provides adequate exposure for treatment of all types of acetabular fractures. We describe our experience with an easier, relatively less invasive pubic symphysis approach (PSA) for the treatment of acetabular fractures. Material/Methods Between March 2011 and March 2012, fifteen patients with acetabular fracture underwent surgery using the PSA technique. Fracture reduction and treatment outcomes were assessed by clinical and radiological examination. Operation time, intraoperative blood loss and postoperative complications were documented. Results Mean operative time was 222±78 minutes. Average blood loss was 993±361 mL. Anatomical reduction was achieved in all patients. Minimum follow-up period was 31 months. Postoperative hypoesthesia in the area of innervation of the lateral femoral cutaneous nerve was reported in one patient, with spontaneous recovery at one month after surgery. No complications were reported during the follow-up period. At the most recent follow up, clinical outcomes were graded as “excellent” in six patients, “good” in eight patients and “fair” in one patient based on the modified Merle d’Aubigné-Postel score. Conclusions PSA appears to be a timesaving and safe approach for treatment of acetabular fractures that affords good visual access and allows for excellent fracture reduction. Our preliminary results revealed a much lower incidence of complications than traditional approaches, suggesting PSA is an alternative for treatment of acetabular fractures. PMID:27734825
... knee bend. Compression Stockings Can Be Hard to Put on If it's hard for you to put on the stockings, try these tips: Apply lotion ... your legs, but let it dry before you put on the stockings. Use a little baby powder ...
Seradge, H; Nagle, K R; Miller, R J
To determine the amount of anteversion or retroversion of the acetabular component of the implanted total hip prosthesis, two anteroposterior radiographs of the hip are obtained, with the contralateral hip flexed to compensate for the possible existing flexion contracture. The X-ray beam is centered on the implanted total hip in one radiograph, and moved away from it toward the contralateral hip in the second radiograph. If the cup is anteverted, the opening will seem wider in the second radiograph. To calculate the angle, the location of the center of the X-ray beam on the X-ray plate must be know. The center of the X-ray beam can be marked on the radiograph by putting a metalic cross on the patient, over the centering cross of the X-ray light source. If the distance of the signature of the X-ray's center beam is less than 8 mm for the center of the cup on the X-ray film, the cup version can be calculated from the arcsin of the shortest to the largest diameter of the cup. If the central ray's signature is farther away, correction is necessary for this calculation. Also, the variable parameters, e.g., cup size, and magnification rate, should be considered in the calculations. The anteroposterior radiographs of the implanted total hip, obtained with the central beam being marked on the X-ray plate, not only are useful for evaluation of the implant but also can be used to calculate the version angle with an accuracy of +/-2 degrees. The necessary calculation is tabulated for cups with an outside diameter of 44-56 mm.
Mechlenburg, Inger; Kold, Søren; Søballe, Kjeld
The purpose of this study was to assess acetabular bone mineral density after periacetabular osteotomy and to examine whether bone mineral density correlates with postoperative migration of the osteotomised acetabular fragment. Twenty-five female and three male patients scheduled for periacetabular osteotomy were consecutively included. The patients were scanned by dual energy X-ray absorptiometry (DEXA) at 1 week, 1 year, and 2 1/2 years after surgery. Radiostereometric analyses (RSA) were done at 1, 4, 8, and 24 weeks after surgery. Two and a half years after periacetabular osteotomy, no significant changes in bone mineral density or any biological effect on bone remodelling due a changed loading pattern in the acetabulum could be detected. There was no significant correlation between bone mineral density and migration of the acetabulum. Dual energy X-ray absorptiometry is not an appropriate method to demonstrate the changes in bone mineral density after periacetabular osteotomy or to predict postoperative acetabular migration.
McKellop, H; Shen, F W; DiMaio, W; Lancaster, J G
Crosslinking of ultrahigh molecular weight polyethylene has been shown to markedly improve its wear resistance in clinical studies and laboratory tests using hip joint simulators. However, because most of the laboratory studies have been done under clean conditions using prosthesis-quality, highly polished counterfaces, there is concern regarding how well an intentionally crosslinked polyethylene acetabular cup will resist abrasion by a femoral ball that has been damaged by third-body abrasion in vivo. To investigate this, conventional and radiation crosslinked-remelted acetabular cups of ultra-high molecular weight polyethylene were tested in a hip joint simulator bearing against smooth femoral balls and against balls with moderate and severe roughening. Cups were tested with and without aging to accelerate any oxidative degradation. The crosslinked cups were produced by exposing extruded GUR 4150 bar stock of ultrahigh molecular weight polyethylene to 5 Mrad gamma radiation under a partial vacuum and then the bars were remelted to extinguish residual free radicals. Artificial aging at 70 degrees C under 5 atm oxygen for 14 days induced negligible oxidation in the crosslinked and remelted material. Against smooth balls, the wear of the crosslinked cups, with or without aging, averaged approximately 15% of that of the conventional cups. Against the moderately rough balls, the wear rate of the conventional cups was unchanged, whereas the wear rate increased slightly for the nonaged and aged crosslinked cups, but was still only 26% and 20% of that of the conventional cups, respectively. Against extremely rough balls, the mean wear rates increased markedly for each material such that during the final 1 million cycle interval, the average wear rates of the nonaged and the aged crosslinked cups were 72% and 47% of that of the conventional cups, respectively. That is, the crosslinked polyethylene showed substantially better wear resistance than conventional polyethylene
Teusink, Matthew J; Callaghan, John J; Warth, Lucian C; Goetz, Devon D; Pedersen, Douglas R; Johnston, Richard C
The purpose of the study was to evaluate the 10- to 18-year follow-up of cementless acetabular fixation in patients 50 years and younger. We retrospectively reviewed a consecutive group of 118 patients (144 hips) in whom primary total hip arthroplasty had been performed by 2 surgeons using a cementless acetabular component. Two (1.4%) cementless acetabular components were revised because of aseptic loosening. Twenty-four hips (16.7%) were revised for any mechanical failure of the acetabular component mostly related to acetabular liner wear and osteolysis. The average linear wear rate was 0.19 mm per year, which was higher than our previous reports with cemented acetabular fixation. The fiber mesh ingrowth surface of the cementless acetabular component in this study was superior to cemented acetabular components in terms of fixation. However, the high rates of wear and osteolysis have led to poor overall acetabular component construct survivorship.
Wada, Hiroshi; Mishima, Hajime; Yoshizawa, Tomohiro; Sugaya, Hisashi; Nishino, Tomofumi; Yamazaki, Masashi
Background In cementless total hip arthroplasty, imageless computer-assisted navigation is usually used to register the anterior pelvic plane (APP). The accuracy of this method is influenced by the subcutaneous tissues overlying the registration landmarks. On the other hand, the acetabular center axis (ACA) is determined from the acetabular rim. Precise registration of the ACA is possible because of direct palpation using a pointer. Imageless navigation using the ACA usually targets patients with normal acetabular morphology. The aim of this study was to investigate the accuracy of imageless navigation using the ACA instead of the APP in patients with normal or deformed acetabular rims. Methods The intraoperative cup position was compared with that obtained from the postoperative computed tomography (CT) images in 18 cases. Results The inclination angle derived from the navigation system was 3.4 ± 5.3 degrees smaller and the anteversion angle was 1.4 ± 3.1 degrees larger than those derived from the CT images. Conclusion The inclination cup angle of the navigation system was significantly inferior to the true value, particularly in cases with large anterior osteophytes. PMID:27073586
Petersen, Brian D.; Wolf, Bryan; Lambert, Jeffrey R.; Clayton, Carolyn W.; Glueck, Deborah H.; Jesse, Mary Kristen; Mei-Dan, Omer
Patients with developmental dysplasia of the hip often have compensatory labral hypertrophy, which presumably lends stability to an unstable joint. Conversely, patients with acetabular overcoverage may have small or ossified labra. The purpose of this study is to explore the interaction of labral length with the degree of acetabular hip coverage. A retrospective cohort of patients with hip pain presenting to a hip preservation center, who had undergone hip magnetic resonance imaging and AP pelvis radiographs were studied. General linear multivariate models were used to assess the association between three measures of labral length (lateral, anterior and anterior inferior locations along the acetabular rim) and the X-ray derived lateral center edge angle (LCEA) of Wiberg. Of the three acetabular labral locations measured, only the lateral labrum was associated with LCEA Wiberg (P = 0.0008). Lateral labral length increases as LCEA of Wiberg decreases. The anterior and anterior inferior labral locations did not show a predictable increase in labral length as LCEA Wiberg decreased. PMID:27583157
Squire, Matthew; Griffin, William L; Mason, J Bohannon; Peindl, Richard D; Odum, Susan
Acetabular component deformation secondary to forces encountered during insertion is a potential consequence of the press-fit technique. This study characterized the stiffness of Pinnacle 100 cups (DePuy, Warsaw, Ind) via mechanical testing and used this information with intraoperative measurements of cup deformation to calculate the in vivo forces acting on cups inserted during hip arthroplasty in 21 patients. We found that 90.5% of cups had measurable compression deformity, averaging 0.16 +/- 0.16 mm. The corresponding forces acting on these cups averaged 414 +/- 421 N. For hard-on-hard bearing surfaces, such in vivo deformation of acetabular shells may result in negative clinical consequences such as equatorial loading with increased wear and potential seizing of components, chipping of ceramic inserts, or locking mechanism damage.
Kawashima, A; Murayama, S; Ohuchida, T; Russell, W J
On retrospective reviews of radiographs, periarthritis calcarea was distinguished from os acetabula by interval radiographic progression and regression. Among 59 men and 51 women, there were 137 instances of para-acetabular calcifications and ossifications, which were morphologically classified as 58 discrete, 58 amorphous, and 21 segmented types. Correlations with other radiographic abnormalities, symptoms, signs, and laboratory abnormalities were sought, but not established. Out of 93 serially imaged opacities, 90 changed, including 37 of the 40 instances (92.5%) of the discrete type and 53 instances (100%) of the amorphous and segmented types--due to periarthritis calcarea. At least 43 of 90 densities were newly developed. Mean age at first detection was 47.7 years. Three of the discrete densities were unchanged and represented os acetabula. Thus, recognition of para-acetabular periarthritis calcarea is not only of academic importance; it can facilitate proper treatment as well.
Moreta, J; Foruria, X; Labayru, F
Sciatic nerve injuries associated with acetabular fractures can be post-traumatic, perioperative or postoperative. Late postoperative injury is very uncommon and can be due to heterotopic ossifications, muscular scarring, or implant migration. A case is presented of a patient with a previous transverse acetabular fracture treated with a reconstruction plate for the posterior column. After 17 years, she presented with progressive pain and motor deficit in the sciatic territory. Radiological and neurophysiological assessments were performed and the patient underwent surgical decompression of the sciatic nerve. A transection of the nerve was observed that was due to extended compression of one of the screws. At 4 years postoperatively, her pain had substantially diminished and the paresthesias in her leg had resolved. However, her motor symptoms did not improve. This case report could be relevant due to this uncommon delayed sciatic nerve injury due to prolonged hardware impingement.
Nicholl, J. E.; Koka, S. R.; Bintcliffe, I. W.; Addison, A. K.
Twenty-eight unstable total hip arthroplasties were treated with an acetabular augmentation wedge. Of the hips, 23 have had no further dislocations at a mean follow-up of 26 months. Five patients continued to dislocate and have needed further surgery. To our knowledge this is the largest reported series of acetabular augmentation with as good results as those of the most successful reported series of this technique, and a success rate comparable to other methods of treating recurrent dislocation. Careful patient selection, and using a thin augmentation wedge to avoid impingement, are important to the success of a technique which is a useful option in the management of recurrent dislocation. Images Figure 1 PMID:10364973
Nguyen, Huong Van; Chiam, Quee Li; Dixson, Hugh; Goddard, Kim A
Retroperitoneal haematoma is rarely described in the context of bone scintigraphy, as it is usually an incidental discovery on bone scan carried out for another purpose. We report a case of a right retroperitoneal haematoma detected on Tc-99m-methylene diphosphonate bone scintigraphy taken in an elderly patient presenting with a mechanical fall and a right acetabular fracture.
Hothi, H S; Busfield, J J C; Shelton, J C
Metal press-fit cups and shells are widely used in hip resurfacing and total hip replacement procedures. These acetabular components are inserted into a reamed acetabula cavity by either impacting their inner polar surface (shells) or outer rim (cups). Two-dimensional explicit dynamics axisymmetric finite element models were developed to simulate these impaction methods. Greater impact velocities were needed to insert the components when the interference fit was increased; a minimum velocity of 2 m/s was required to fully seat a component with a 2 mm interference between the bone and outer diameter. Changing the component material from cobalt-chromium to titanium alloy resulted in a reduction in the number of impacts on the pole to seat it from 14 to nine. Of greatest significance, it was found that locking a rigid cap to the cup or shell rim resulted in up to nine fewer impactions being necessary to seat it than impacting directly on the polar surface or using a cap free from the rim of the component, as is the case with many commercial resurfacing cup impaction devices currently used. This is important to impactor design and could make insertion easier and also reduce acetabula bone damage.
Berthonnaud, E; Hilmi, R; Dimnet, J
The goal of this paper is to access to pelvis position and morphology in standing posture and to determine the relative locations of their articular surfaces. This is obtained from coupling biplanar radiography and bone modeling. The technique involves different successive steps. Punctual landmarks are first reconstructed, in space, from their projected images, identified on two orthogonal standing X-rays. Geometric models, of global pelvis and articular surfaces, are determined from punctual landmarks. The global pelvis is represented as a triangle of summits: the two femoral head centers and the sacral plateau center. The two acetabular cavities are modeled as hemispheres. The anterior sacral plateau edge is represented by an hemi-ellipsis. The modeled articular surfaces are projected on each X-ray. Their optimal location is obtained when the projected contours of their models best fit real outlines identified from landmark images. Linear and angular parameters characterizing the position of global pelvis and articular surfaces are calculated from the corresponding sets of axis. Relative positions of sacral plateau, and acetabular cavities, are then calculated. Two hundred standing pelvis, of subjects and scoliotic patients, have been studied. Examples are presented. They focus upon pelvis orientations, relative positions of articular surfaces, and pelvis asymmetries.
... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Hip joint (hemi-hip) acetabular metal cemented... HUMAN SERVICES (CONTINUED) MEDICAL DEVICES ORTHOPEDIC DEVICES Prosthetic Devices § 888.3370 Hip joint (hemi-hip) acetabular metal cemented prosthesis. (a) Identification. A hip joint (hemi-hip)...
... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Hip joint (hemi-hip) acetabular metal cemented... HUMAN SERVICES (CONTINUED) MEDICAL DEVICES ORTHOPEDIC DEVICES Prosthetic Devices § 888.3370 Hip joint (hemi-hip) acetabular metal cemented prosthesis. (a) Identification. A hip joint (hemi-hip)...
... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Hip joint (hemi-hip) acetabular metal cemented... HUMAN SERVICES (CONTINUED) MEDICAL DEVICES ORTHOPEDIC DEVICES Prosthetic Devices § 888.3370 Hip joint (hemi-hip) acetabular metal cemented prosthesis. (a) Identification. A hip joint (hemi-hip)...
... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Hip joint (hemi-hip) acetabular metal cemented... HUMAN SERVICES (CONTINUED) MEDICAL DEVICES ORTHOPEDIC DEVICES Prosthetic Devices § 888.3370 Hip joint (hemi-hip) acetabular metal cemented prosthesis. (a) Identification. A hip joint (hemi-hip)...
Peters, Frank M; Greeff, Richard; Goldstein, Neal; Frey, Chris T
Acetabular cup placement in total hip arthroplasty is often difficult to assess, especially in the lateral position and using the posterior approach. Conventional techniques and computer-assisted surgery are the 2 most popular methods for proper placement of the acetabular cup in Lewinnek's safe zone of orientation (anteversion 15° ± 10° and lateral inclination 40° ± 10°). We developed a system that uses the accelerometer and camera function of the iPhone. A level indicator application and protractor application were downloaded to the iPhone and used to improve acetabular cup placement. This system has proven to be accurate and quick. Our series of 50 prospective cases showed good results with all our acetabular cups being placed within a narrow range in the safe zone and with less than 5% difference between the preoperative, intraoperative, and postoperative acetabular inclinations.
Zhang, Henghui; Wang, Yiping; Ai, Songtao; Chen, Xiaojun; Wang, Liao; Dai, Kerong
Determining three-dimensional (3D) acetabular orientation is important for several orthopaedic scenarios, but the complex geometries of both pelvis and acetabulum make measurements of orientation unreliable. Acetabular orientation may also differ between the sexes or racial groups. We aimed to (1) establish and evaluate a novel method for measuring 3D acetabular orientation, (2) apply this new method to a large population of Chinese subjects, and (3) report relevant characteristics of native acetabular orientation in this population. We obtained computed tomography scans taken for non-orthopaedic indications in 100 Chinese subjects (50 male, 50 female). A novel algorithm tailored to segmentation of the hip joint was used to construct 3D pelvic models from these scans. We developed a surface-based method to establish a reliable 3D pelvic coordinate system and software to semi-automatically measure 3D acetabular orientation. Differences in various acetabular orientations were compared within and between subjects, between male and female subjects, and between our subjects and subjects previously reported by another group. The reported method was reliable (intraclass correlation coefficient >0.999). Acetabular orientations were symmetrical within subjects, but ranged widely between subjects. The sexes differed significantly in acetabular anteversion (average difference, 3.0°; p < 0.001) and inclination (1.5°; p < 0.03). Acetabular anteversion and inclination were substantially smaller among our Chinese subjects than previously reported for American subjects. Thus, our method was reliable and sensitive, and we detected sex differences in 3D acetabular orientation. Awareness of differences between the sexes and races is the first step towards better reconstruction of the hip joint for all individuals and could also be applied to other orthopaedic scenarios. PMID:28207829
Pakvis, Dean F M; Heesterbeek, Petra J C; Severens, Marianne; Spruit, Maarten
Background and purpose — The acetabular component has remained the weakest link in hip arthroplasty for achievement of long-term survival. One of the possible explanatory factors for acetabular failure has been acetabular stress shielding. For this, we investigated the effects of a cementless elastic socket on acetabular bone mineral density (BMD). Patients and methods — During 2008–2009, we performed a single-center prospective cohort trial on 25 patients (mean age 64 (SD 4), 18 females) in whom we implanted a cementless elastic press-fit socket. Using quantitative BMD measurements on CT, we determined the change in BMD surrounding the acetabular component over a 2-year follow-up period. Results — We found a statistically significant decrease in cancellous BMD (−14% to −35%) and a stable level of cortical BMD (5% to −5%) surrounding the elastic press-fit cup during the follow-up period. The main decrease was seen during the first 6 months after implantation. During the second year, cancellous BMD showed a further decrease in the medial and lower acetabular regions. Interpretation — We found no evidence that an elastic press-fit socket would prevent acetabular stress shielding during a 2-year follow-up. PMID:27659074
De Paolis, Massimiliano; Romagnoli, Carlo; Alì, Nikolin; Giannini, Sandro; Donati, Davide Maria
Introduction. The management of pelvic tumors is a challenge for orthopaedic oncologists due to the complex anatomy of the pelvis and the need to have extensive exposure. Various reconstructive techniques have been proposed with poor functional results and a high percentage of complications. Our purpose is to determine the functional results and the rate of complications of iliac stem prosthesis for acetabular defects following resections for periacetabular tumors. Materials and Methods. Between 1999 and 2012, 45 patients underwent pelvic resections for periacetabular bone tumors followed by reconstruction with stem cup prosthesis. The most common diagnosis was CS (chondrosarcoma, 29 cases), followed by OS (osteosarcoma, 9 cases) and metastasis (3 cases). In 33 cases, this implant was associated with massive bone allografts. Minimum follow-up required to evaluate functional outcome was 2 years. We classified pelvic resections according to Enneking and Dunham's classification and we used MSTS (musculoskeletal tumor system) score to evaluate functional outcomes. Results and Discussion. Sixteen patients died of their disease, three were lost to follow-up, four are alive with disease, and twenty-two are alive with no evidence of disease. Fifteen patients had local recurrence. Sixteen patients had bone or lung metastasis. We have had 6 infections, 2 aseptic loosening, and 2 cases of hip dislocation. Iliac sovracetabular osteotomy was fused in all cases at 10 months from surgery. Functional results were good or excellent in 25 of 31 patients with long-term follow-up (77%), with a percentage similar to that reported in the literature. Conclusion. The use of iliac stem prosthesis is a simple reconstructive technique that reduces operative times and risk of infection. It allows having good results and low rate of complications, but it should be performed in selected cases and centres of reference. PMID:24250275
Murphy, Colin G.; Carrothers, Andrew D.
Summary Although technically challenging even for the experienced surgeon, simultaneous open reduction and internal fixation (ORIF) of acetabular fracture and total hip replacement (THR) have some potential advantages over the more traditional treatment options in specific patient subgroups; theoretically allowing immediate weight bearing and faster rehabilitation, reducing the cost of inpatient stay, and reducing the risks of early and late local complications associated with standard treatment for this type of injury. We review the evolution of the indications and techniques, outline the surgical challenges, and discuss implant options and outcomes for this treatment paradigm. PMID:28228787
Pajarinen, Jarkko; Hirvensalo, Eero
We have developed a 2-incision technique for rotational acetabular osteotomy. This includes both an extraperitoneal and an anterolateral exposure of the pelvic bones allowing an unconstrained approach without dissection of the muscle insertion. 2 plates are used to stabilize the osteotomy and full range motion of the hip is permitted within 2 days of surgery, while weight bearing is restricted for 6 weeks after the operation. We reviewed the complications and technical results in 27 patients (28 hips) after a minimum follow-up of mean 3 (1-5) years. No major surgical complications occurred, but dysfunction of the lateral femoral cutaneous nerve occurred frequently (14 patients). The radiographical correction of the femoral head covering was similar to those in previous reports of rotational osteotomy. The range of hip motion was not affected by the operation. A significant increase in the mean Merle D'Aubigné and Harris Hip scores was observed in a subgroup of 20 patients with a minimum follow-up of 2 years. In conclusion, the method we have used is safe and the early results are satisfactory.
van Arkel, R. J.; Amis, A. A.; Cobb, J. P.; Jeffers, J. R. T.
In this in vitro study of the hip joint we examined which soft tissues act as primary and secondary passive rotational restraints when the hip joint is functionally loaded. A total of nine cadaveric left hips were mounted in a testing rig that allowed the application of forces, torques and rotations in all six degrees of freedom. The hip was rotated throughout a complete range of movement (ROM) and the contributions of the iliofemoral (medial and lateral arms), pubofemoral and ischiofemoral ligaments and the ligamentum teres to rotational restraint was determined by resecting a ligament and measuring the reduced torque required to achieve the same angular position as before resection. The contribution from the acetabular labrum was also measured. Each of the capsular ligaments acted as the primary hip rotation restraint somewhere within the complete ROM, and the ligamentum teres acted as a secondary restraint in high flexion, adduction and external rotation. The iliofemoral lateral arm and the ischiofemoral ligaments were primary restraints in two-thirds of the positions tested. Appreciation of the importance of these structures in preventing excessive hip rotation and subsequent impingement/instability may be relevant for surgeons undertaking both hip joint preserving surgery and hip arthroplasty. Cite this article: Bone Joint J 2015; 97-B:484–91. PMID:25820886
Ibragimov, Bulat; Likar, Boštjan; Pernuš, Franjo; Vrtovec, Tomaž
In this paper, we propose a segmentation algorithm by which anatomical landmarks on the pelvis are extracted from computed tomography (CT) images. The landmarks are used to automatically define the anterior (AASA) and posterior acetabular sector angles (PASA) describing the degree of hip misalignment. The center of each femoral head is obtained by searching for the point at which most intensity gradient vectors defined at edge points intersect. The radius of each femoral head is computed by finding the sphere, positioned at the center of the femoral head, for which the normalized sum of gradient vector magnitudes on the sphere surface is maximal. The anterior and posterior corners of each acetabulum are searched for on a curve representing the acetabulum and defined by dynamic programming. The femoral head centers and anterior and posterior corners are used to calculate the AASA and PASA. The algorithm was applied to CT images of 120 normal subjects and the results were compared to ground truth values obtained by manual segmentation. The mean absolute difference (+/- standard deviation) between the obtained and ground truth values was 1.3 +/- 0.3 mm for the femoral head centers and 2.1 +/- 1.3 degrees for the acetabular angles.
Michel, Adrien; Bosc, Romain; Meningaud, Jean-Paul; Hernigou, Philippe; Haiat, Guillaume
Background The primary stability of the acetabular cup (AC) implant is an important determinant for the long term success of cementless hip surgery. However, it remains difficult to assess the AC implant stability due to the complex nature of the bone-implant interface. A compromise should be found when inserting the AC implant in order to obtain a sufficient implant stability without risking bone fracture. The aim of this study is to evaluate the potential of impact signals analyses to assess the primary stability of AC implants inserted in cadaveric specimens. Methods AC implants with various sizes were inserted in 12 cadaveric hips following the same protocol as the one employed in the clinic, leading to 86 different configurations. A hammer instrumented with a piezoelectric force sensor was then used to measure the variation of the force as a function of time produced during the impact between the hammer and the ancillary. Then, an indicator I was determined for each impact based on the impact momentum. For each configuration, twelve impacts were realized with the hammer, the value of the maximum amplitude being comprised between 2500 and 4500 N, which allows to determine an averaged value IM of the indicator for each configuration. The pull-out force F was measured using a tangential pull-out biomechanical test. Results A significant correlation (R2 = 0.69) was found between IM and F when pooling all data, which indicates that information related to the AC implant biomechanical stability can be retrieved from the analysis of impact signals obtained in cadavers. Conclusion These results open new paths in the development of a medical device that could be used in the future in the operative room to help orthopedic surgeons adapt the surgical protocol in a patient specific manner. PMID:27893757
Plain radiographs are the most important diagnostic means for determining the indication and following up on total hip arthroplasty. The acetabular cup position can be easily determined by applying trigonometric functions. This report presents an even simpler method. The short axis of the projected ellipse is measured and related to the total cross-section of the projected cup along the short axis. This relationship correlates with acetabular cup anteversion angles and represents an inverse sinus function. A close linear correlation is seen within the most common interval from 10 degrees to 30 degrees. Anteversion is between 23 degrees to 24 degrees when the ellipse bisects the total acetabular cross-section. This means that simply measuring the length of the short ellipse axis and the total length of the projected cross-section along the short axis provides the radiographic acetabular anteversion. Nonorthogonal projected radiographs should be corrected first.
Hugate, Ronald R; Dickey, Ian D; Chen, Qingshan; Wood, Christina M; Sim, Franklin H; Rock, Michael G
Secure fixation of acetabular components in total hip arthroplasty can be challenging. The purpose of this study was to perform biomechanical analysis of cup fixation strength using fixed-angle vs standard screw fixation. Multihole, porous-backed acetabular prostheses were implanted in both acetabuli of 8 cadaveric pelves using standard press-fit techniques. Fixed-angle screws were used on the left side, and standard cancellous screws were used in the right. The use of fixed-angle screws enhanced acetabular fixation substantially under subfailure cyclic loading conditions and load-to-failure. The triradiate screw configuration increases the bending moment required to fail the specimens as well. Fixed-angle screws may be useful for achieving rigid fixation of acetabular prostheses in challenging clinical scenarios.
Rivkin, Gurion; Kandel, Leonid; Qutteineh, Bilal; Liebergall, Meir; Mattan, Yoav
Patients with peri-acetabular osteolysis around a well fixed cementless acetabular component may be treated with liner exchange. When the locking mechanism is unreliable or unavailable, cementing the liner into the fixed acetabular component is a feasible option. The purpose of this study was to evaluate the clinical and radiographic long term results of this technique. Forty hip revisions with liner cementation in 37 patients were performed. The minimum follow up was 10 years. Modified Harris Hip Score and recent x rays were reviewed. Four hips were re-revised. Two patients were diagnosed with exacerbation of osteolysis but refused revision. Dislocation rate was relatively high (16%). Liner cementation technique in revision hip surgery is useful in patients with a well fixed metal backed acetabular component.
Tissingh, Elizabeth K; Johnson, Abigail; Queally, Joseph M; Carrothers, Andrew D
Acetabular fractures in older patients are challenging to manage. The “fix and replace” construct may present a new paradigm for the management of these injuries. We present the current challenge of acetabular fractures in older patients. We present this in the context of the current literature. This invited editorial presents early results from our centre and the ongoing challenges are discussed. PMID:28361014
Chana-Rodríguez, Francisco; Mañanes, Rubén Pérez; Rojo-Manaute, José; Moran-Blanco, Luz María; Vaquero-Martín, Javier
Retained sponges after a surgical treatment of polytrauma may cause a broad spectrum of clinical symptoms and present a difficult diagnostic problem. We report a case of retained surgical sponge in a 35-year-old man transferred from another hospital, that sustained a open acetabular fracture. The fracture was reduced through a limited ilio-inguinal approach. After 4 days, he presented massive wound dehiscence of the surgical approach. An abdominal CT scan showed, lying adjacent to the outer aspect of the left iliac crest, a mass of 10 cm, identified as probable foreign body. The possibility of this rare complication should be in the differential diagnosis of any postoperative patient who presents with pain, infection, or palpable mass. PMID:26312116
Samaan, Michael A.; Teng, Hsiang-Ling; Kumar, Deepak; Lee, Sonia; Link, Thomas; Majumdar, Sharmila; Souza, Richard B.
Background Patients with acetabular cartilage defects reported increased pain and disability compared to those without acetabular cartilage defects. The specific effects of acetabular cartilage defects on lower extremity coordination patterns are unclear. The purpose of this study was to determine hip and knee joint coordination variability during gait in those with and without acetabular cartilage defects. Methods A combined approach, consisting of a semi-quantitative MRI-based quantification method and vector coding, was used to assess hip and knee joint coordination variability during gait in those with and without acetabular cartilage lesions. Findings The coordination variability of the hip flexion-extension/knee rotation, hip abduction-adduction/knee rotation and hip rotation/knee rotation joint couplings were reduced in the acetabular lesion group compared to the control group during loading response of the gait cycle. The lesion group demonstrated increased variability in the hip flexion-extension/knee rotation and hip abduction-adduction/knee rotation joint couplings, compared to the control group, during the terminal stance/pre-swing phase of gait. Interpretation Reduced variability during loading response in the lesion group may suggest reduced movement strategies and a possible compensation mechanism for lower extremity instability during this phase of the gait cycle. During terminal stance/pre-swing, a larger variability in the lesion group may suggest increased movement strategies and represent a compensation or pain avoidance mechanism caused by the load applied to the hip joint. PMID:26298706
Garrett, Jeffrey; Halvorson, Jason; Carroll, Eben; Webb, Lawrence X
The complex anatomy of the pelvis and acetabulum have historically made classification and interpretation of acetabular fractures difficult for orthopedic trainees. The addition of 3-dimensional (3-D) computed tomography (CT) scan has gained popularity in preoperative planning, identification, and education of acetabular fractures given their complexity. Therefore, the authors examined the value of 3-D CT compared with conventional radiography in classifying acetabular fractures at different levels of orthopedic training. Their hypothesis was that 3-D CT would improve correct identification of acetabular fractures compared with conventional radiography.The classic Letournel fracture pattern classification system was presented in quiz format to 57 orthopedic residents and 20 fellowship-trained orthopedic traumatologists. A case consisted of (1) plain radiographs and 2-dimensional axial CT scans or (2) 3-D CT scans. All levels of training showed significant improvement in classifying acetabular fractures with 3-D vs 2-D CT, with the greatest benefit from 3-D CT found in junior residents (postgraduate years 1-3).Three-dimensional CT scans can be an effective educational tool for understanding the complex spatial anatomy of the pelvis, learning acetabular fracture patterns, and correctly applying a widely accepted fracture classification system.
Callaghan, J J; Liu, S S; Phruetthiphat, O-A
A common situation presenting to the orthopaedic surgeon today is a worn acetabular liner with substantial acetabular and pelvic osteolysis. The surgeon has many options for dealing with osteolytic defects. These include allograft, calcium based substitutes, demineralised bone matrix, or combinations of these options with or without addition of platelet rich plasma. To date there are no clinical studies to determine the efficacy of using bone-stimulating materials in osteolytic defects at the time of revision surgery and there are surprisingly few studies demonstrating the clinical efficacy of these treatment options. Even when radiographs appear to demonstrate incorporation of graft material CT studies have shown that incorporation is incomplete. The surgeon, in choosing a graft material for a surgical procedure must take into account the efficacy, safety, cost and convenience of that material.
Jiang, Nan; Peng, Lin; Al-Qwbani, Mohammed; Xie, Guo-Ping; Yang, Qin-Meng; Chai, Yu; Zhang, Qing; Yu, Bin
Abstract Anatomic data regarding femoral version, neck-shaft angle, and acetabular anteversion are still limited in Chinese Han adult population. The aim of this study was to investigate the effects of age, sex, and body laterality on the 3 important anatomic indicators in Chinese Han healthy adults. Measurements were performed independently by 3 experienced observers using the picture archiving and communication system (PACS) in healthy adults who had received imaging tests of the femur and acetabulum between January 2009 and October 2014. Relevant data were measured and analyzed. A total of 466 adults (353 males and 113 females) were included. The mean femoral version, neck-shaft angle, and acetabular anteversion for all were 10.62, 133.02, and18.79, respectively. Age-based analysis showed that adults younger than 60 years had a significantly higher neck-shaft angle (P < 0.001) but a significantly lower acetabular anteversion (P < 0.001) than those older than 60 years. Sex-based analysis revealed that females had significantly higher values of femoral version (P < 0.001) and acetabular anteversion (P < 0.001) than males. Laterality-based analysis found the left side had a significantly lower acetabular anteversion (P < 0.001) than the right side. Outcomes of multiple linear regression analysis indicated that femoral version may be associated with sex (P < 0.001) but not age (P = 0.076) or laterality (P = 0.430), neck-shaft angle may be associated with age (P < 0.001) but not sex (P = 0.378) or laterality (P = 0.233), and acetabular anteversion may be associated with age (P < 0.001) and sex (P < 0.001) but not laterality (P = 0.060). In this representative Chinese cohort, neck-shaft angle may decrease, whereas acetabular anteversion may increase with age, females may have higher values of femoral version and acetabular anteversion than males, and the right body side may have a higher value of acetabular
Background and Purpose Acetabular fractures are often combined with associated injuries to the hip joint. Some of these associated injuries seem to be responsible for poor long-term results and these injuries seem to affect the outcome independent of the quality of the acetabular reduction. The aim of our study was to analyze the outcome of both column acetabular fractures and the influence of osseous cofactors such as initial fracture displacement, hip dislocation, femoral head lesions and injuries of the acetabular joint surface. Methods A retrospective cohort study in patients with both column acetabular fractures treated over a 30 year period was performed. Patients with a follow-up of more than two years were invited for a clinical and radiological examination. Displacement was analyzed on initial and postoperative radiographs. Contusion and impaction of the femoral head was grouped. Injuries of the acetabular joint surface consisting of impaction, contusion and comminution were recorded. The Merle d’Aubigné Score was documented and radiographs were analysed for arthritis (Helfet classification), femoral head avascular necrosis (Ficat/Arlet classification) and heterotopic ossifications (Brooker classification). Results 115 patients were included in the follow up examination. Anatomic reduction (malreduction ≤ 1mm) was associated with a significantly better clinical outcome than nonanatomical reduction (p = 0.001). Initial displacement of more than 10mm (p = 0.031) and initial intraarticular fragments (p = 0.041) were associated with worse outcome. Other associated injuries, such as the presence of a femoral head dislocation, femoral head injuries and injuries to the acetabular joint surface showed no significant difference in outcome individually, but in fractures with more than two associated local injuries the risk for joint degeneration was significant higher (p < 0.001) than in cases with less than two of them. In the subgroup of
Bollini, Gérard; Legaye, Jean; Tardieu, Christine; Prat-Pradal, Dominique; Chabrol, Brigitte; Jouve, Jean-Luc; Duval-Beaupère, Ginette; Pélissier, Jacques
Acetabular cup orientation (inclination and anteversion) is a fundamental topic in orthopaedics and depends on pelvis tilt (positional parameter) emphasising the notion of a safe range of pelvis tilt. The hypothesis was that pelvic incidence (morphologic parameter) could yield a more accurate and reliable assessment than pelvis tilt. The aim was to find out a predictive equation of acetabular 3D orientation parameters which were determined by pelvic incidence to include in the model. The second aim was to consider the asymmetry between the right and left acetabulae. Twelve pelvic anatomic specimens were measured with an electromagnetic Fastrak system (Polhemus Society) providing 3D position of anatomical landmarks to allow measurement of acetabular and pelvic parameters. Acetabulum and pelvis data were correlated by a Spearman matrix. A robust linear regression analysis provided prediction of acetabulum axes. The orientation of each acetabulum could be predicted by the incidence. The incidence is correlated with the morphology of acetabula. The asymmetry of the acetabular roof was correlated with pelvic incidence. This study allowed analysis of relationships of acetabular orientation and pelvic incidence. Pelvic incidence (morphologic parameter) could determine the safe range of pelvis tilt (positional parameter) for an individual and not a group. PMID:25006461
Clutter, Sarah Y; Morgan, Steven J; Erickson, Mark; Smith, Wade R; Stahel, Philip F
Background: Open acetabular fractures in children are rare, but potentially devastating injuries. Secondary to the low incidence, there is an apparent lack of reports on appropriate management strategies for open pediatric acetabular fractures in the literature. Methods: Description of a case study. Results: A 3 years and ten months-old girl was ejected as a passenger from an all terrain vehicle. She sustained a displaced, grade IIIA open left anterior column acetabular fracture. The injury was treated by extending the open wound to a formal first window of the ilioinguinal approach. After surgical debridement, the anterior column was reduced anatomically and fixed by two lag screws which avoided the tri-radiate cartilage. A vaginal laceration was debrided and repaired. The patient was treated in a spica cast without weight bearing on the left lower extremity for 8 weeks. No perioperative complications occurred. The acetabular fracture healed in an anatomic position within 8 weeks. To avoid premature closure of the tri-radiate cartilage, the patient underwent a physeal bar resection at one year after injury. At two-year follow up, she was walking and running without pain and had a free range of motion of her left hip. Conclusions: Operative management should represent the therapy of choice for open, displaced pediatric acetabular fractures. After fracture healing, a scheduled physeal bar resection may be required for injuries which involve the tri-radiate cartilage. PMID:19461903
Brown, N M; Hellman, M; Haughom, B H; Shah, R P; Sporer, S M; Paprosky, W G
A pelvic discontinuity occurs when the superior and inferior parts of the hemi-pelvis are no longer connected, which is difficult to manage when associated with a failed total hip replacement. Chronic pelvic discontinuity is found in 0.9% to 2.1% of hip revision cases with risk factors including severe pelvic bone loss, female gender, prior pelvic radiation and rheumatoid arthritis. Common treatment options include: pelvic plating with allograft, cage reconstruction, custom triflange implants, and porous tantalum implants with modular augments. The optimal technique is dependent upon the degree of the discontinuity, the amount of available bone stock and the likelihood of achieving stable healing between the two segments. A method of treating pelvic discontinuity using porous tantalum components with a distraction technique that achieves both initial stability and subsequent long-term biological fixation is described.
Gregory, Thomas; Vandenbussche, Eric
Background This study aimed to measure femoral head penetration before occurrence of real wear, and to quantify the portions attributable respectively to clearance and plastic deformations in various acetabular designs. Methods We analyzed CT scans from 15 patients at ‘day five’ after total hip arthroplasty (THA). All patients received Exafit® femoral stems and 28 mm heads: 5 patients had cemented Durasul® all-PE cups, 5 patients had un-cemented Allofit® metal-backed cups, and 5 patients had un-cemented Stafit® dual-mobility cups. We also analyzed CT scans of samples of the three head-cup combinations to compare in vivo and in vitro measurements. Results The mean femoral head penetration measured on ‘day five’ was lower for all-PE cups (0.196 mm) than for metal-backed cups (0.551 mm) and dual-mobility cups (0.634 mm). Conclusions The present study indicates that isolated measurements of femoral head penetration include 0.15–0.46 mm of radial clearance and 0.05–0.27 mm of creep, and confirms that the majority of so-called bedding-in observed in the first post-operative months is not entirely due to wear. PMID:27162781
Satsuma, Shinichi; Kobayashi, Daisuke; Kinugasa, Maki; Takeoka, Yoshiki; Kuroda, Ryosuke; Kurosaka, Masahiro
The aim of this study was to find a new predictive indicator for acetabular growth of developmental dysplasia of the hip. Seventy-three hips that were diagnosed with developmental dysplasia of the hip and treated by conservative reduction were included in our study. In 30 hips with center-edge angle ≤ 10° at age 4, the center-edge of the acetabular limbus angle (CEALA) in the arthrogram was measured. On the basis of the results, CEALA was significantly smaller in the secondary acetabular dysplasia group than in the normal group at maturity. In conclusion, CEALA is a more reliable and accurate predictive indicator for acetabular development than center-edge angle or acetabular index.
Fan, Yanping; Lei, Jianyin; Zhu, Feng; Li, Zhiqiang; Chen, Weiyi; Liu, Ximing
This study aims to evaluate the biomechanical mechanism of fixation systems in the most frequent T-shaped acetabular fracture using finite element method. The treatment of acetabular fractures was based on extensive clinical experience. Three commonly accepted rigid fixation methods (double column reconstruction plates (P × 2), anterior column plate combined with posterior column screws (P + PS), and anterior column plate combined with quadrilateral area screws (P + QS)) were chosen for evaluation. On the basis of the finite element model, the biomechanics of these fixation systems were assessed through effective stiffness levels, stress distributions, force transfers, and displacements along the fracture lines. All three fixation systems can be used to obtain effective functional outcomes. The third fixation system (P + QS) was the optimal method for T-shaped acetabular fracture. This fixation system may reduce many of the risks and limitations associated with other fixation systems. PMID:26495030
Central acetabular fractures with dislocation are usually the result of high-energy trauma, resulting in joint incongruity, and are frequently associated with other injuries. Open reduction and internal fixation has been the standard treatment for acetabular fractures, but it is associated with extensive surgical trauma, and complications such as haematoma formation, iatrogenic nerve injury, and heterotopic ossification. We present the case of a 63-year-old female who sustained a central acetabular fracture of the hip with dislocation as a result of an automobile collision. Closed reduction of the dislocation was performed, and the fracture was managed by minimally invasive plate osteosynthesis using a specially prepared plate. At 01 year postoperatively, radiographs showed the fracture to have been well-healed with good congruity of the joint. However, heterotopic ossification of the joint was noted. The technique allowed reduction of the fracture with minimal surgical trauma.
Reinitz, Steven D; Currier, Barbara H; Van Citters, Douglas W; Levine, Rayna A; Collier, John P
This investigation analyzed retrieved sequentially crosslinked and annealed (SXL) ultra-high molecular weight polyethylene bearings to determine whether the material is chemically stable in vivo. A series of retrieved tibial and acetabular components were analyzed for changes in ketone oxidation, crosslink density, and free radical concentration. Oxidation was observed to increase with in vivo duration, and the rate of oxidation in tibial inserts was significantly greater than in acetabular liners. SXL acetabular bearings oxidized at a rate comparable to gamma-sterilized liners, while SXL tibial inserts oxidized at a significantly faster rate than their gamma-sterilized counterparts. A significant decrease in crosslink density with increased mean ketone oxidation index was observed, suggesting that in vivo oxidation may be causing material degradation. Furthermore, a subsurface whitened damage region was also found in a subset of the bearings, indicating the possibility of a clinically relevant decrease in mechanical properties of these components.
Hofmann, Aaron A; Prince, Edward J; Drake, F Thurston; Hunt, Kenneth J
Cementation of a liner into a well-fixed acetabular shell is common in revision hip arthroplasty. We compare the biomechanical strengths of cemented liners with standard locked liners. Fifty polyethylene liners were inserted into acetabular shells using the standard locking mechanism or 1 of 2 cement types then loaded to failure by torsion or lever-out testing. Lever-out testing showed that all cemented liners failed at similar loads to standard locked liners. With torsion testing, cemented liners failed at significantly higher loads than standard locked liners; roughening the liner increased load to failure. Cementation of an acetabular liner into a metal shell is safe and strong and a good alternative to metal shell replacement. Saw roughening of the polyethylene liner strengthens the poly-cement interface.
Ortega-Briones, A.; Smith, S.
Background. Interest in arthroplasty techniques for periarticular or intra-articular fractures in the elderly/osteoporotic patient continues to rise, including for geriatric acetabular fractures. In line with this, many acetabular fracture surgeons are now undertaking acute total hip arthroplasty in elderly/osteoporotic patients. Little is known however of the outcomes of this procedure, beyond the first year after surgery. Questions/Purposes. We determined the clinical outcomes of a series of elderly osteoporotic patients (mean age at surgery 77.4 years) treated for acetabular fractures with column fixation and simultaneous total hip arthroplasty, at a mean of 49 months after surgery. Methods. 24 patients (25 hips) were reviewed at a mean of 49 months after surgery. The surgical technique employed has previously been described. Radiographs were obtained, and clinical outcomes were assessed using Harris Hip Scores and the Merle d'Aubigné score. Results. 14 hips were available for assessment (9 deceased, 2 lost to follow-up). No patient suffered any complications beyond the perioperative period, no acetabular components were loose clinically or on latest radiographs, and the mean Harris Hip Score was 92. All but one patient scored good or excellent on the Merle d'Aubigné score. Conclusions. Column fixation and simultaneous total hip arthroplasty are a viable option for complex geriatric acetabular fractures, with encouraging midterm results. We conclude that THR is a viable long-term solution in this situation provided that the acetabular columns are stabilised prior to implantation, but more research is needed to aid in overall management decision making. PMID:28194414
Acetabular perforation after medial migration of the helical blade through the femoral head after treatment of an unstable trochanteric fracture with proximal femoral nail antirotation (PFNA): a case report.
Takigami, Iori; Ohnishi, Kazuichiro; Ito, Yoshiki; Nagano, Akihito; Sumida, Hisashi; Tanaka, Kaori; Shimizu, Katsuji
The proximal femoral nail antirotation is a new generation of intramedullary device for the treatment of trochanteric femoral fractures, having a helical blade rather than a screw for suggested better purchase in osteoporotic bone. However, it is not free of complications. Few reports are available on postoperative perforation of the helical blade through the femoral head as a unique complication of proximal femoral nail antirotation. We report a 79-year-old woman with acetabular perforation after migration of the helical blade through the femoral head after an unstable trochanteric fracture, which was fixed with a proximal femoral nail antirotation.
Anwar, Iwan Budiwan; Saputra, Eko; Ismail, Rifky; Jamari, J.; van der Heide, Emile
Fixation of acetabular cup to bone material is an important initial stability for artificial hip joint. In general, the fixation in cement less-type acetabular cup uses press-fit and screw methods. These methods can be applied alone or together. Based on literature survey, the additional screw inside of cup is effective; however, it has little effect in whole fixation. Therefore, an acetabular cup with good fixation, easy manufacture and easy installation is required. This paper is aiming at evaluating and proposing a new cup fixation design. To prove the strength of the present cup fixation design, the finite element simulation of three dimensional cup with new fixation design was performed. The present cup design was examined with twist axial and radial rotation. Results showed that the proposed cup design was better than the general version.
Buller, Leonard T; Lawrie, Charles M; Vilella, Fernando E
Acetabular fractures in the elderly are most frequently the result of low-energy trauma and present unique management challenges to orthopedic surgeons. Evaluation and treatment should be performed in a multidisciplinary fashion with early involvement of internal medicine subspecialists and geriatricians. Distinct fracture patterns and pre-existing osteoarthritis and osteoporosis necessitate careful preoperative planning. The role of total hip arthroplasty should also be considered when surgical treatment is indicated. The outcomes of acetabular fractures in the elderly have improved, but complications remain higher and results less satisfactory than in younger individuals. The lack of randomized controlled trials has limited the ability to establish an evidence-based treatment algorithm.
Jlalia, Zied; Bellil, Mehdi; Ghachem, Maher Ben
Stress fracture of acetabular roof is an unusual cause of hip pain. It is considered as an underdiagnosed entity. People who are more susceptible to experience this fracture are athletes, soldiers and dancers. We present the case of an 11 year old girl with a roof acetabular stress fracture for which the diagnosis and follow-ups were possible by the means of MRI. The treatment was keeping the child at a complete rest. Failure to abide with this treatment can cause the stress fracture to evaluate into a complete fracture. PMID:28154643
Tsao, Audrey; Pesut, Tracy; Peacock, Charity; Tucci, Michelle; Buckhalter, Ruth Ann
Between 4/5/99 and 5/20/2002, our university performed 31 total hip arthroplasties in 27 young patients utilizing a conservative hip prosthesis developed at the Mayo Clinic. Eleven patients underwent Bipolar replacement, while the remaining twenty required an acetabular component. The patients ranged in age from 25 to 50 (mean of 39.9). The mean follow up was 12.4 months (range 4.5-27). Twenty-eight hips were treated for AVN secondary to RA, HIV, ETOH abuse, and SLE; while two underwent THA for OA secondary to trauma, and one for JRA. Three patients were lost to follow up at less than 6 months and were excluded from the study. The patients were followed for a minimum of 6 months utilizing the Harris hip score, the Charnley hip score, and radiographic evaluation including subsidence, radiolucency, and calcar resorption. Four patients (13%) had subsidence ranging from 1 to 3 mm at the most recent visit. One patients (3.2%) had radiographic evidence of radiolucency measuring 2 mm. Nine patients (29%) developed 1-3 mm of calcar resorption. No hips required revision. Thirty patients had improvement in their Harris hip score and Charnley hip score. The one patient who decreased his score had developed AVN secondary to ETOH abuse. Three hips had an intra-operative complication of lateral cortex penetration and required circlage wiring. Comparisons were made utilizing Multiple Logistic Regression to determine if preoperative BMI, Dorr score, and gender had an impact on the postoperative hip scores or degree of osteolysis, subsidence, and calcar resorption. Although the Harris hip score and Charnley hip scores significantly improved postoperatively, the preoperative BMI, Dorr score, and gender did not correlate with patient outcome. Our patients improved clinically in pain level, function and ROM. Further follow up will reveal if this component truly preserves bone stock for ease of future revision.
We reviewed the results of 17 consecutive revision total hip arthroplasties performed with the use of freeze-dried irradiated bone allograft in 15 patients. These allografts were used in conjunction with five Kerboull rings, two steel meshes and ten cemented isolated cups. All the patients have had a follow-up of at least 5 years. The patients were evaluated clinically and radiographically. No revisions were necessary and X-rays confirmed partial or total ingrowth of the allografts. In acetabular revision surgery, hip reconstruction can be successfully treated by freeze-dried irradiated and chemically treated allografts. Additional studies with longer term follow-up are necessary to confirm this outcome. PMID:17828537
Sano, Kei; Homma, Yasuhiro; Baba, Tomonori; Ando, Jun; Matsumoto, Mikio; Kobayashi, Hideo; Yuasa, Takahito; Kaneko, Kazuo
We present a case of successful and uncomplicated total hip arthroplasty with an acetabular reinforcement device in an elderly patient with hip osteoarthritis already diagnosed with factor XI deficiency, which is a very rare bleeding disorder and at high risk of post-operative haemorrhage, and it poses a substantial challenge to surgeons as a consequence of the specific risks of infection and fixation failure. Moreover, bone fragility in elderly patient increases potential risk of adverse event. Fresh frozen plasma was used to supplement factor XI activity. Importantly, transfusion-transmitted disease such as having factor XI inhibitor was promptly surveyed prior to the supplement since the patient had previous history of the administration of fresh frozen plasma. Under prompt and effective peri-operative haemostasis, rigid implant fixation and rigorous attention to the prevention of infection seem to achieve the best possible outcomes for elderly patients with a bleeding disorder undergoing total hip arthroplasty. PMID:28186870
Distel, Brenda D.
This project is designed to teach students the process of buying stocks and to tracking their investments over the course of a semester. The goals of the course are to teach students about the relationships between conditions in the economy and the stock market; to predict the effect of an economic event on a specific stock or industry; to relate…
Summary Background Acetabular chondral defect are very frequently associated to FAI. Treatment options are still questionable. Methods Between 2008 and 2014, 201 patients over 583 have been arthroscopically treated with the AMIC procedure for grade III and/or IV acetabular chondral lesions. Patients age was between 18 and 50 years; acetabular chondral lesion size was between 2 and 4 cm2; radiological Tönnis degree of osteoarthritis was ≤ 2. Results The mean follow up of the entire group of 201 patients was 5 years (from 8 to 2). Significant improvement, as measured by the mHHS, was observed at 6 months in comparison to preoperative levels (80.3 ± 8.3) (p<0.001). Continuous improvement with respect to each previous evaluation time point was seen, reaching the highest improvement level at the three year follow-up (85.5 ± 7.2). The mean mHHS improvement recorded at the five year follow-up compared with preoperative scores was 39.1 ± 5.9. Conclusions AMIC is a valid procedure to repair medium-sized chondral defects on the acetabular side of the hip found during treatment of FAI and lead to long-term favourable outcomes. Level of evidence IV. PMID:28066742
Alshuhri, Abdullah A; Holsgrove, Timothy P; Miles, Anthony W; Cunningham, James L
Current techniques for diagnosing early loosening of a total hip replacement (THR) are ineffective, especially for the acetabular component. Accordingly, new, accurate, and quantifiable methods are required. The aim of this study was to investigate the viability of vibrational analysis for accurately detecting acetabular component loosening. A simplified acetabular model was constructed using a Sawbones(®) foam block. By placing a thin silicone layer between the acetabular component and the Sawbones block, 2- and 4-mm soft tissue membranes were simulated representing different loosening scenarios. A constant amplitude sinusoidal excitation with a sweep range of 100-1500 Hz was used. Output vibration from the model was measured using an accelerometer and an ultrasound probe. Loosening was determined from output signal features such as the number and relative strength of observed harmonic frequencies. Both measurement methods were sufficient to measure the output vibration. Vibrational analysis reliably detected loosening corresponding to both 2 and 4 mm tissue membranes at driving frequencies between 100 and 1000 Hz (p < 0.01) using the accelerometer. In contrast, ultrasound detected 2-mm loosening at a frequency range of 850-1050 Hz (p < 0.01) and 4-mm loosening at 500-950 Hz (p < 0.01).
Giannoudis, P V; Da Costa, A A; Raman, R; Mohamed, A K; Smith, R M
Injury to the sciatic nerve is one of the more serious complications of acetabular fracture and traumatic dislocation of the hip, both in the short and long term. We have reviewed prospectively patients, treated in our unit, for acetabular fractures who had concomitant injury to the sciatic nerve, with the aim of predicting the functional outcome after these injuries. Of 136 patients who underwent stabilisation of acetabular fractures, there were 27 (19.9%) with neurological injury. At initial presentation, 13 patients had a complete foot-drop, ten had weakness of the foot and four had burning pain and altered sensation over the dorsum of the foot. Serial electromyography (EMG) studies were performed and the degree of functional recovery was monitored using the grading system of the Medical Research Council. In nine patients with a foot-drop, there was evidence of a proximal acetabular (sciatic) and a distal knee (neck of fibula) nerve lesion, the double-crush syndrome. At the final follow-up, clinical examination and EMG studies showed full recovery in five of the ten patients with initial muscle weakness, and complete resolution in all four patients with sensory symptoms (burning pain and hyperaesthesia). There was improvement of functional capacity (motor and sensory) in two patients who presented initially with complete foot-drop. In the remaining 11 with foot-drop at presentation, including all nine with the double-crush lesion, there was no improvement in function at a mean follow-up of 4.3 years.
Autograft - bone; Allograft - bone; Fracture - bone graft; Surgery - bone graft; Autologous bone graft ... Fuse joints to prevent movement Repair broken bones (fractures) that have bone loss Repair injured bone that ...
Schmitz, M W J L; Timmer, C; Rijnen, W H C; Gardeniers, J W M; Schreurs, B W
Despite the worldwide usage of the cemented Contemporary acetabular component (Stryker), no published data are available regarding its use in patients aged < 50 years. We undertook a mid- to long-term follow-up study, including all consecutive patients aged < 50 years who underwent a primary total hip replacement using the Contemporary acetabular component with the Exeter cemented stem between January 1999 and January 2006. There were 152 hips in 126 patients, 61 men and 65 women, mean age at surgery 37.6 years (16 to 49 yrs). One patient was lost to follow-up. Mean clinical follow-up of all implants was 7.6 years (0.9 to 12.0). All clinical questionnaire scores, including Harris hip score, Oxford hip score and several visual analogue scales, were found to have improved. The eight year survivorship of all acetabular components for the endpoints revision for any reason or revision for aseptic loosening was 94.4% (95% confidence interval (CI) 89.2 to 97.2) and 96.4% (95% CI 91.6 to 98.5), respectively. Radiological follow-up was complete for 146 implants. The eight year survival for the endpoint radiological loosening was 93.1% (95% CI 86.2 to 96.6). Three surviving implants were considered radiologically loose but were asymptomatic. The presence of acetabular osteolysis (n = 17, 11.8%) and radiolucent lines (n = 20, 13.9%) in the 144 surviving cups indicates a need for continued observation in the second decade of follow-up in order to observe their influence on long-term survival. The clinical and radiological data resulting in a ten-year survival rate > 90% in young patients support the use of the Contemporary acetabular component in this specific patient group.
Klatte, Till Orla; Kendoff, Daniel; Sabihi, Reza; Kamath, Atul F; Rueger, Johannes M; Gehrke, Thorsten
During the one-stage exchange procedure for periprosthetic joint infection (PJI) after total hip arthroplasty (THA), acetabular defects challenge reconstructive options. Porous tantalum augments are an established tool for addressing acetabular destruction in aseptic cases, but their utility in septic exchange is unknown. This retrospective case-control study presents the initial results of tantalum augmentation during one-stage exchange for PJI. Primary endpoints were rates of re-infection and short-term complications associated with this technique. Study patients had no higher risk of re-infection with equivalent durability at early follow-up with a re-infection rate in both groups of 4%. In conclusion, tantalum augments are a viable option for addressing acetabular defects in one-stage exchange for septic THA. Further study is necessary to assess long-term durability when compared to traditional techniques for acetabular reconstruction.
Claus, B; Van Innis, B; De Witte, E; Van Overschelde, J; Magotteaux, B; Fatemi, F; Vandepaer, F
The results of 190 primary total hip arthroplasties with a Harris-Galante cementless acetabular cup were reviewed. All patients had a minimum follow-up of 3 years (range, 3 to 5.5 years, mean 46 months). Clinical and radiographical analysis was performed. Inguinal pain was recorded in five cases. We noted a fracture of a screw in four cases without further implications. There was no evidence of acetabular loosening. There was no migration of the acetabular cup. No acetabular component showed measurable wear of the polyethylene liner. Non-progressive radiolucent lines were recorded in 14% of the patients: among these patients, radiolucent lines were noted in zone 1 in 46%, in zone 2 in 4% and in zone 3 in 86%. Two socket revisions became necessary. One patient suffered a deep-seated infection. Another revision was necessary because of recurrent dislocation.
Ceretti, M; Fanelli, M; Pappalardo, S
The acetabular shell mobilization is the main long-term complication in total hip replacement. Metal-back fracture has also to be considered among the possible causes of shell mobilization. A case is presented of bilateral acetabular shell mobilization due to the trabecular covering de-soldering from the metal-back in a 43 year-old patient, 13-14 years after the first surgery.
Ayers, David C.; Greene, Meridith; Snyder, Benjamin; Aubin, Michelle; Drew, Jacob; Bragdon, Charles
Background: Radiostereometric analysis provides highly precise measurements of component micromotion relative to the bone that is otherwise undetectable by routine radiographs. This study compared, at a minimum of five years following surgery, the micromotion of tantalum and titanium acetabular cups and femoral head penetration in highly cross-linked polyethylene liners and conventional (ultra-high molecular weight polyethylene) liners in active patients who had undergone total hip replacement. Methods: This institutional review board-approved prospective, randomized, blinded study involved forty-six patients. Patients were randomized into one of four cohorts according to both acetabular cup and polyethylene liner. Patients received either a cementless cup with a titanium mesh surface or a tantalum trabecular surface and either a highly cross-linked polyethylene liner or an ultra-high molecular weight polyethylene liner. Radiostereometric analysis examinations and Short Form-36 Physical Component Summary, Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), University of California Los Angeles (UCLA) activity, and Harris hip scores were obtained preoperatively, postoperatively, at six months, and annually thereafter. Results: All patients had significant improvement (p < 0.05) in Short Form-36 Physical Component Summary, WOMAC, UCLA activity, and Harris hip scores postoperatively. On radiostereometric analysis examination, highly cross-linked polyethylene liners showed significantly less median femoral head penetration at five years (p < 0.05). Steady-state wear rates from one year to five years were 0.04 mm per year for ultra-high molecular weight polyethylene liners and 0.004 mm per year for highly cross-linked polyethylene liners. At the five-year follow-up, the median migration (and standard error) was 0.05 ± 0.20 mm proximally for titanium cups and 0.21 ± 0.05 mm for tantalum cups. Conclusions: In this young population who had undergone
Tumor - bone; Bone cancer; Primary bone tumor; Secondary bone tumor; Bone tumor - benign ... The cause of bone tumors is unknown. They often occur in areas of the bone that grow rapidly. Possible causes include: Genetic defects ...
Bhatt, Reena A; Rozental, Tamara D
Replacement of missing bone stock is a reconstructive challenge to upper extremity surgeons and decision-making with regards to available choices remains difficult. Preference is often given to autograft in the form of cancellous, cortical, or corticocancellous grafts from donor sites. However, the available volume from such donor sites is limited and fraught with potential complications. Advances in surgical management and medical research have produced a wide array of potential substances that can be used for bone graft substitute. Considerations in selecting bone grafts and substitutes include characteristic capabilities, availability, patient morbidity, immunogenicity, potential disease transmission, and cost variability.
Anderson, Christine; Cook, Stan
Offers a field-tested stock market unit designed to develop mathematical skills involving fractions and decimals, basic understanding of the stock market, and hypothesis testing skills in real world situations. Includes tables displaying questions, tally sheets, and instructions, as well as a list of related activities. (MDH)
Aşık, Mehmet; Erşen, Ali; Polat, Gökhan; Bilgili, Fuat; Tunalı, Onur
The purpose of this study was to present the case report of a 7-year-old patient who was treated with hip arthroscopy for an acetabular osteoid osteoma. A 7-year-old patient was referred to our clinic with hip pain. In the assessment of the patient, an acetabular osteoid osteoma was detected in his right hip; it was adjacent to his triradiate cartilage. An arthroscopic surgery was planned as an alternative to open safe hip dislocation. The osteoid osteoma was completely removed with hip arthroscopy. Postoperative CT scanning and histopathological analysis confirmed the diagnosis. Exposure of the acetabulum can be problematic in paediatric patients due to the potential risks of open safe dislocation. Hip arthroscopy can safely be used for benign hip lesions in paediatric patients. Level of evidence Case report, Level V.
Gascoyne, Trevor C; Dyrkacz, Richard M; Turgeon, Thomas R; Burnell, Colin D; Wyss, Urs P; Brandt, Jan-M
Eight retrieved metal-on-metal total hip replacements displayed corrosion damage along the cobalt-chromium alloy liner taper junction with the Ti alloy acetabular shell. Scanning electron microscopy indicated the primary mechanism of corrosion to be grain boundary and associated crevice corrosion, which was likely accelerated through mechanical micromotion and galvanic corrosion resulting from dissimilar alloys. Coordinate measurements revealed up to 4.3mm(3) of the cobalt-chromium alloy taper surface was removed due to corrosion, which is comparable to previous reports of corrosion damage on head-neck tapers. The acetabular liner-shell taper appears to be an additional source of metal corrosion products in modular total hip replacements. Patients with these prostheses should be closely monitored for signs of adverse reaction towards corrosion by-products.
Buy, Xavier; Cazzato, Roberto Luigi; Catena, Vittorio; Roubaud, Guilhem; Kind, Michele; Palussiere, Jean
Bone metastases are a common finding in oncology. They often induce pain but also fractures which impair quality of life, especially when involving weight-bearing bones. Percutaneous image-guided consolidation techniques play a major role for the management of bone metastases. Cementoplasty aims to stabilize bone and control pain by injecting acrylic cement into a weakened bone. This minimally invasive technique has proven its efficacy for bones submitted to compression forces: vertebra, acetabular roof, and condyles. However, long bone diaphysis should be treated with caution due to lower resistance of the cement subject to torsional forces. The recent improvements of navigation systems allow percutaneous image-guided screw fixation without requiring open surgery. This fast-track procedure avoids postponing introduction of systemic therapies. If needed, cementoplasty can be combined with screw insertion to ensure better anchoring in major osteolysis. Interventional radiology bone consolidation techniques increase the therapeutic field in oncology. A multidisciplinary approach remains mandatory to select the best indications.
Tadros, Ayman M. A.; Oxland, Thomas R.; O'Brien, Peter
Introduction. A method for the determination of safe angles for screws placed in the posterior acetabular wall based on preoperative computed tomography (CT) is described. It defines a retroacetabular angle and determines its variation in the population. Methods. The retroacetabular angle is the angle between the retroacetabular surface and the tangent to the posterior acetabular articular surface. Screws placed through the marginal posterior wall at an angle equal to the retroacetabular angle are extraarticular. Medial screws can be placed at larger angles whose difference from the retroacetabular angle is defined as the allowance angles. CT scans of all patients with acetabular fractures treated in our institute between September 2002 to July 2007 were used to measure the retroacetabular angle and tangent. Results. Two hundred thirty one patients were included. The average (range) age was 42 (15–74) years. The average (range) retroacetabular angle was 39 (30–47) degrees. The average (range) retroacetabular tangent was 36 (30–45) mm. Conclusions. Placing the screws at an average (range) angle of 39 (33–47) degrees of anterior inclination with the retroacetabular surface makes them extraarticular. Angles for medial screws are larger. Safe angles can be calculated preoperatively with a computer program. PMID:24959359
Lewis, Cara L.; Khuu, Anne; Marinko, Lee
Developmental dysplasia of the hip is often diagnosed in infancy, but less severe cases of acetabular dysplasia are being detected in young active adults. The purpose of this case report is to present a non-surgical intervention for a 31-year-old female with mild acetabular dysplasia and an anterior acetabular labral tear. The patient presented with right anterior hip and groin pain, and she stood with the trunk swayed posterior to the pelvis (swayback posture). The hip pain was reproduced with the anterior impingement test. During gait, the patient maintained the swayback posture and reported 6/10 hip pain. Following correction of the patient’s posture, the patient’s pain rating was reduced to a 2/10 while walking. The patient was instructed to maintain the improved posture. At the 1 year follow-up, she demonstrated significantly improved posture in standing and walking. She had returned to recreational running and was generally pain-free. The patient demonstrated improvement on self-reported questionnaires for pain, function and activity. These findings suggest that alteration of posture can have an immediate and lasting effect on hip pain in persons with structural abnormality and labral pathology. PMID:25731688
Guimarães, Rodrigo Pereira; Kaleka, Camila Cohen; Cohen, Carina; Daniachi, Daniel; Keiske Ono, Nelson; Honda, Emerson Kiyoshi; Polesello, Giancarlo Cavalli; Riccioli, Walter
Objective: Correlate the postoperative radiographic evaluation with variables accompanying acetabular fractures in order to determine the predictive factors for segmental impaction of femoral head. Methods: Retrospective analysis of medial files of patients submitted to open reduction surgery with internal acetabular fixation. Within approximately 35 years, 596 patients were treated for acetabular fractures; 267 were followed up for at least two years. The others were excluded either because their follow up was shorter than the minimum time, or as a result of the lack of sufficient data reported on files, or because they had been submitted to non-surgical treatment. The patients were followed up by one of three surgeons of the group using the Merle d'Aubigné and Postel clinical scales as well as radiological studies. Results: Only tow studied variables-age and amount of postoperative reductionshowed statistically significant correlation with femoral head impaction. Conclusions: The quality of reduction-anatomical or with up to 2mm residual deviation-presents a good radiographic evolution, reducing the potential for segmental impaction of the femoral head, a statistically significant finding. PMID:27004191
Song, Yongnam; Ito, Hiroshi; Kourtis, Lampros; Safran, Marc R; Carter, Dennis R; Giori, Nicholas J
The acetabular labrum is believed to have a sealing function. However, a torn labrum may not effectively prevent joint fluid from escaping a compressed joint, resulting in impaired lubrication. We aimed to understand the role of the acetabular labrum in maintaining a low friction environment in the hip joint. We did this by measuring the resistance to rotation (RTR) of the hip, which reflects the friction of the articular cartilage surface, following focal and complete labrectomy. Five cadaveric hips without evidence of osteoarthritis and impingement were tested. We measured resistance to rotation of the hip joint during 0.5, 1, 2, and 3 times body weight (BW) cyclic loading in the intact hip, and after focal and complete labrectomy. Resistance to rotation, which reflects articular cartilage friction in an intact hip was significantly increased following focal labrectomy at 1-3 BW loading, and following complete labrectomy at all load levels. The acetabular labrum appears to maintain a low friction environment, possibly by sealing the joint from fluid exudation. Even focal labrectomy may result in increased joint friction, a condition that may be detrimental to articular cartilage and lead to osteoarthritis.
Kopydlowski, Nathan J.; Tannenbaum, Eric P.; Smith, Matthew V.; Sekiya, Jon K.
Background: Labral tears often occur in the same quadrant of the acetabulum at a small depression previously referred to as the psoas valley. Understanding the anatomic variations of this depression could help us understand the etiology of labral tears. Purpose: To describe the location and dimensions of the depression located in the anterosuperior acetabular rim. The hypothesis was that the location of this depression would be consistent with the common location of acetabular labral tears described in the literature. Study Design: Controlled laboratory study. Methods: A total of 240 pelvic specimens were divided into 2 groups (n = 120 for each) according to age (younger age group: 21.36 ± 3.12 years [range, 14-24 years]; older age group: 42.30 ± 10.27 years, [range, 25-60 years]).Specimens were also categorized based on sex (mean age: 31.93 ± 12.31 years [male]; 32.08 ± 13.66 years [female]) and race (mean age: 31.45 ± 13.16 years [black]; 32.57 ± 12.82 years [white]). The depth and width of the acetabular depression were measured using a digital caliper, and the location was measured using a goniometer. Results: The psoas valley was observed in every specimen and was located in the anterosuperior quadrant of the acetabulum. Its depth was significantly greater (P < .001) in males (5.35 ± 1.60 mm) than in females (3.95 ± 1.31 mm). The width of the psoas valley was also greater (P < .001) in males (29.39 ± 3.98 mm) than in females (24.49 ± 4.80 mm). There were no differences in size or location of the depression between races or age groups. The psoas valley was located between 3.92 ± 0.42 o’clock anteriorly and 2.12 ± 0.77 o’clock posteriorly. Conclusion: The differences observed in the study data are believed to be a result of the different anatomic morphologies of the pelvis in males and females. This loss of bony support, caused by the depression, could be the underlying cause of weakening of the acetabular labrum as people age. Clinical Relevance
Sun, Xiao-Qian; Shen, Hua-Wei; Cheng, Xue-Qi
Stock price prediction is an important and challenging problem for studying financial markets. Existing studies are mainly based on the time series of stock price or the operation performance of listed company. In this paper, we propose to predict stock price based on investors' trading behavior. For each stock, we characterize the daily trading relationship among its investors using a trading network. We then classify the nodes of trading network into three roles according to their connectivity pattern. Strong Granger causality is found between stock price and trading relationship indices, i.e., the fraction of trading relationship among nodes with different roles. We further predict stock price by incorporating these trading relationship indices into a neural network based on time series of stock price. Experimental results on 51 stocks in two Chinese Stock Exchanges demonstrate the accuracy of stock price prediction is significantly improved by the inclusion of trading relationship indices. PMID:24429767
Sun, Xiao-Qian; Shen, Hua-Wei; Cheng, Xue-Qi
Stock price prediction is an important and challenging problem for studying financial markets. Existing studies are mainly based on the time series of stock price or the operation performance of listed company. In this paper, we propose to predict stock price based on investors' trading behavior. For each stock, we characterize the daily trading relationship among its investors using a trading network. We then classify the nodes of trading network into three roles according to their connectivity pattern. Strong Granger causality is found between stock price and trading relationship indices, i.e., the fraction of trading relationship among nodes with different roles. We further predict stock price by incorporating these trading relationship indices into a neural network based on time series of stock price. Experimental results on 51 stocks in two Chinese Stock Exchanges demonstrate the accuracy of stock price prediction is significantly improved by the inclusion of trading relationship indices.
Tiberi, John V; Antoci, Valentin; Malchau, Henrik; Rubash, Harry E; Freiberg, Andrew A; Kwon, Young-Min
This retrospective study measured the change of the acetabular component orientation between supine and standing radiographs in 113 THA patients and identified the associated anatomical parameters that may help direct pre-operative planning. The mean change of the acetabular component inclination and version from supine to standing was 4.6° and 5.9° respectively (P<0.0001), with 49 (43%) hips showing inclination change >5° and 69 (53%) hips showing version change >5°. Twelve (43%) of 28 'malpositioned' cups became 'well-positioned' and 26 (31%) of 85 'well-positioned' cups became 'malpositioned' upon standing. Changes in inclination were associated with leg length discrepancy and pelvic obliquity; and changes in version were associated with pelvic tilt and pelvic incidence. Standing position and patient factors should be considered when defining "optimal" acetabular orientation.
Noiseux, Nicolas O; Long, William J; Mabry, Tad M; Hanssen, Arlen D; Lewallen, David G
Uncemented tantalum acetabular components were introduced in 1997. The purpose was to determine the 2- to 10-year results with this implant material in primary total hip arthroplasty. Our registry identified all primary total hip cases with porous tantalum cups implanted from 1997 to 2004. Clinical outcomes and radiographs were studied. 613 cases were identified. Seventeen percent of patients were lost to follow-up. Twenty-five reoperations were performed (4.4%). Acetabular cup removal occurred in 6 cases (1.2%). No cups were revised for aseptic loosening. Incomplete radiolucent lines were found on 9.3% of initial postoperative radiographs. At 2 years, 67% had resolved. Zero new radiolucent lines were detected. Two- to 10-year results of porous tantalum acetabular components for primary total hip arthroplasty demonstrate high rates of initial stability and apparent ingrowth.
Fukui, Kiyokazu; Kaneuji, Ayumi; Fukushima, Mana; Matsumoto, Tadami
The pathophysiology of rapidly destructive osteoarthritis (OA) of the hip is unknown. This study documented cases of inversion of the acetabular labrum, which has clinicoradiologic features similar to those of initial-stage rapidly destructive hip OA. Our study was based on a prospective review of data for 9 patients with rapidly destructive hip OA. Intraoperative findings showed that the anterosuperior portion of the acetabular labrum had inverted into the articular space, along with many fragments of articular cartilage, in all patients. Subchondral insufficiency fractures of the femoral heads were seen just under the inverted labra in 8 of the 9 patients. Inversion of the acetabular labrum may be involved in rapid joint-space narrowing and subchondral insufficiency fracture in rapidly destructive hip OA.
Khoo-Summers, Lynnette; Bloom, Nancy J
Dancers are at risk for developing groin pain that is due to acetabular labral tears. Although surgical management of labral tears has been reported extensively, conservative management has been poorly described. This case report describes the examination, diagnosis, and treatment of groin pain in a professional ballet dancer with a suspected acetabular labral tear. Treatment focused on decreasing anterior hip joint stresses and improving the precision of hip motion through correction of alignment and movement impairments noted during functional activities and dance. Successful outcomes included a reduction in pain and return to professional ballet dancing.
Taufiq, Intikhab; Najjad, Muhammad Kazim Raheem; Khan, Naveed; Zia, Osama Bin
Purpose Acetabular fractures are mainly caused by trauma and the incidence is rising in developing countries. Initially these fractures were managed conservatively, due to lack of specialized and dedicated acetabulum surgery centres. Our aim is to study the radiological and functional outcomes of surgical management of acetabular fractures in tertiary care hospital. Materials and Methods Total 50 patients were enrolled. The patients with acetabular fractures were enrolled between the years 2012 to 2014. Patients were evaluated clinically with Harris hip score (HHS) and radiologically with Matta outcome grading. The factors examined include age, gender, fracture pattern, time between injury and surgery, initial displacement and quality of reduction on the final outcome. Results There were 34 males and 16 females. Mean age was 44.20±11.65 years while mean duration of stay was 9.28±2.36 days. Duration of follow-up was 24 months. Most common mechanism of injury was motor vehicle accident (n=37, 74.0%). Open reduction and internal fixation of fractures were performed using reconstruction plates. Mean HHS at 24 months was 82.36±8.55. The clinical outcome was acceptable (excellent or good) in 35 (70.0%) cases and not acceptable (fair or poor) in 15 (30.0%) cases. The radiological outcome was anatomical in 39 (78.0%) cases, congruent in 5 (10.0%) cases, incongruent in 6 (12.0%) cases. Conclusion Study results indicated that mechanism of injury, time between injury and surgery, initial degree of displacement and quality of reduction had significant effect on functional as well as radiological outcome. PMID:28097111
Callary, Stuart A; Solomon, Lucian B; Holubowycz, Oksana T; Campbell, David G; Howie, Donald W
A number of different software programs are used to investigate the in vivo wear of polyethylene bearings in total hip arthroplasty. With wear rates below 0.1 mm/year now commonly being reported for highly cross-linked polyethylene (XLPE) components, it is important to identify the accuracy of the methods used to measure such small movements. The aims of this study were to compare the accuracy of current software programs used to measure two-dimensional (2D) femoral head penetration (FHP) and to determine whether the accuracy is influenced by larger femoral heads or by different methods of representing the acetabular component within radiostereometric analysis (RSA). A hip phantom was used to compare known movements of the femoral head within a metal-backed acetabular component to FHP measured radiographically using RSA, Hip Analysis Suite (HAS), PolyWare, Ein Bild Roentgen Analyse (EBRA), and Roentgen Monographic Analysis Tool (ROMAN). RSA was significantly more accurate than the HAS, PolyWare, and ROMAN methods when measuring 2D FHP with a 28 mm femoral head. Femoral head size influenced the accuracy of HAS and ROMAN 2D FHP measurements, EBRA proximal measurements, and RSA measurements in the proximal and anterior direction. The use of different acetabular reference segments did not influence accuracy of RSA measurements. The superior accuracy and reduced variability of RSA wear measurements allow much smaller cohorts to be used in RSA clinical wear studies than those utilizing other software programs. © 2016 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res.
... Physician Resources Professions Site Index A-Z Bone Biopsy Bone biopsy uses a needle and imaging guidance ... limitations of Bone Biopsy? What is a Bone Biopsy? A bone biopsy is an image-guided procedure ...
Ayeni, Olufemi R; Sansone, Mikael; de Sa, Darren; Simunovic, Nicole; Bedi, Asheesh; Kelly, Bryan T; Farrokhyar, Forough; Karlsson, Jon
Femoro-acetabular impingement (FAI) is increasingly recognized as an important cause of hip pain in the young adult. However, the methods of evaluating the efficacy of surgical intervention are often not validated and/or inconsistently reported. Important clinical, gait, radiographic and biomarker outcomes are discussed. This article (1) presents the rationale for considering a composite outcome for FAI patients; (2) examines a variety of important end points currently used to evaluate FAI surgery; (3) discusses a strategy to generate a composite outcome by combining these end points; and (4) highlights the challenges and current areas of controversy that such an approach to evaluating symptomatic FAI patients may present.
... 26 Internal Revenue 11 2011-04-01 2011-04-01 false Stock for stock of the same corporation. 1.1036...) INCOME TAX (CONTINUED) INCOME TAXES (CONTINUED) Common Nontaxable Exchanges § 1.1036-1 Stock for stock of..., of common stock for common stock, or of preferred stock for preferred stock, in the same...
... 26 Internal Revenue 11 2012-04-01 2012-04-01 false Stock for stock of the same corporation. 1.1036...) INCOME TAX (CONTINUED) INCOME TAXES (CONTINUED) Common Nontaxable Exchanges § 1.1036-1 Stock for stock of..., of common stock for common stock, or of preferred stock for preferred stock, in the same...
... 26 Internal Revenue 11 2014-04-01 2014-04-01 false Stock for stock of the same corporation. 1.1036...) INCOME TAX (CONTINUED) INCOME TAXES (CONTINUED) Common Nontaxable Exchanges § 1.1036-1 Stock for stock of..., of common stock for common stock, or of preferred stock for preferred stock, in the same...
... 26 Internal Revenue 11 2013-04-01 2013-04-01 false Stock for stock of the same corporation. 1.1036...) INCOME TAX (CONTINUED) INCOME TAXES (CONTINUED) Common Nontaxable Exchanges § 1.1036-1 Stock for stock of..., of common stock for common stock, or of preferred stock for preferred stock, in the same...
Hallan, G; Dybvik, E; Furnes, O; Havelin, L I
The Norwegian Arthroplasty Register has shown that several designs of uncemented femoral stems give good or excellent survivorship. The overall findings for uncemented total hip replacement however, have been disappointing because of poor results with the use of metal-backed acetabular components. In this study, we exclusively investigated the medium-to long-term performance of primary uncemented metal-backed acetabular components. A total of 9113 primary uncemented acetabular components were implanted in 7937 patients between 1987 and 2007. These were included in a prospective, population-based observational study. All the implants were modular and metal-backed with ultra-high-molecular-weight polyethylene liners. The femoral heads were made of stainless steel, cobalt-chrome (CoCr) alloy or alumina ceramic. In all, seven different designs of acetabular component were evaluated by the Kaplan-Meier survivorship method and Cox regression analysis. Most acetabular components performed well up to seven years. When the endpoint was revision of the acetabular component because of aseptic loosening, the survival ranged between 87% and 100% at ten years. However, when the endpoint was revision for any reason, the survival estimates were 81% to 92% for the same implants at ten years. Aseptic loosening, wear, osteolysis and dislocation were the main reasons for the relatively poor overall performance of the acetabular components. Prostheses with alumina heads performed slightly better than those with stainless steel or CoCr alloy in subgroups. Whereas most acetabular components performed well at seven years, the survivorship declined with longer follow-up. Fixation was generally good. None of the metal-backed uncemented acetabular components with ultra-high-molecular-weight polyethylene liners in our study had satisfactory long-term results because of high rates of wear, osteolysis, aseptic loosening and dislocation.
de Araújo Loures, Elmano; Simoni, Leandro Furtado; Leite, Isabel Cristina Gonçalves; Loures, Daniel Naya; Loures, Clarice Naya
Objectives To evaluate the short-term performance of a type of implant manufactured in Brazil. Methods This study analyzed a cohort of 60 patients who underwent implantation of MD-4® acetabular components during primary hip arthroplasty procedures performed between January 1, 2010, and August 1, 2012. The patients were studied retrospectively with regard to clinical behavior, stability and radiological osseointegration. The patients were followed up for a minimum of 12 months and a maximum of 42 months (mean: 27) and were evaluated by means of the Harris Hip Score, SF-36 questionnaire and serial conventional radiographs. Results All the components were radiologically stable, without evidence of migration or progressive radiolucency lines. On average, the Harris Hip Score evolved from 36.1 to 92.1 (p < 0.001) and the SF-36 showed significant increases in all its domains (p < 0.001). No differences were observed among patients with osteoarthrosis, osteonecrosis, hip dysplasia or other conditions. Conclusions The short-term results showed clinical and radiological signs of stability and osseointegration of the implants, which may represent a predictive factor regarding medium-term survival of this acetabular component. PMID:26229918
DeBuitleir, Cathal; Soden, Philip; O'Donnchadha, Brian; Tansey, Anthony; Abdulkarim, Ali; McMahon, Colm; Hurson, Conor J.
Revision hip arthroplasty requires comprehensive appreciation of abnormal bony anatomy. Advances in radiology and manufacturing technology have made three-dimensional (3D) representation of osseous anatomy obtainable, which provide visual and tactile feedback. Such life-size 3D models were manufactured from computed tomography scans of three hip joints in two patients. The first patient had undergone multiple previous hip arthroplasties for bilateral hip infections, resulting in right-sided pelvic discontinuity and a severe left-sided posterosuperior acetabular deficiency. The second patient had a first-stage revision for infection and recurrent dislocations. Specific metal reduction protocols were used to reduce artefact. The images were imported into Materialise MIMICS 14.12®. The models were manufactured using selective laser sintering. Accurate templating was performed preoperatively. Acetabular cup, augment, buttress, and cage sizes were trialled using the models, before being adjusted, and resterilised, enhancing the preoperative decision-making process. Screw trajectory simulation was carried out, reducing the risk of neurovascular injury. With 3D printing technology, complex pelvic deformities were better evaluated and treated with improved precision. Life-size models allowed accurate surgical simulation, thus improving anatomical appreciation and preoperative planning. The accuracy and cost-effectiveness of the technique should prove invaluable as a tool to aid clinical practice. PMID:28168060
Looney, R John; Boyd, Allen; Totterman, Saara; Seo, Gwy-Suk; Tamez-Pena, Jose; Campbell, Debbie; Novotny, Leonore; Olcott, Christopher; Martell, John; Hayes, F Ann; O'Keefe, Regis J; Schwarz, Edward M
Osteolysis, which is considered to be a major source of morbidity following total hip joint replacement, has been notoriously difficult to measure accurately, particularly in the acetabular area. In order to study periacetabular osteolysis, specialized software for computerized tomography (CT) scan image analysis has been developed. This software (3D-CT) eliminates metal artifacts, allows three-dimensional segmentation of the CT image, and reconstructs the segmented image to provide an accurate representation and measurement of volume for osteolytic lesions. In the present study, 20 patients underwent periacetabular osteolytic volume determination using 3D-CT, functional assessment (using the Harris Hip Scale, the Western Ontario and McMaster University Osteoarthritis Index, and the short form 36 questionnaire), and two-dimensional analysis of volumetic polyethylene wear using digitalized plain films. Periacetabular osteolysis correlated directly with the polyethylene wear rate (relative risk [RR] = 0.494, P = 0.027). If one patient with an acetabular revision, one patient with recurrent dislocation, and one patient with a Biomet prosthesis are excluded, then the correlation between wear and osteolysis is improved (RR = 0.685, P = 0.002). In summary, the current study demonstrates both the feasibility of CT imaging of periacetabular osteolysis and the correlation between polyethylene wear and osteolytic volume, providing a potential outcome measure for clinical trials that are designed to examine interventions in this complex disease process. PMID:11879538
Pulos, Nicholas; Tiberi Iii, John V; Schmalzried, Thomas P
The standard method for the evaluation of arthritis and postoperative assessment of arthroplasty treatment is observation and measurement from plain films, using the flm edge for orientation. A more recent employment of an anatomical landmark, the ischial tuberosity, has come into use as orientation for evaluation and is called the ischio-lateral method. In this study, the use of this method was evaluated as a first report to the literature on acetabular component measurement using a skeletal reference with lateral radiographs. Postoperative radiographs of 52 hips, with at least three true lateral radiographs taken at different time periods, were analyzed. Component position was measured with the historical method (using the flm edge for orientation) and with the new method using the ischio-lateral method. The mean standard deviation (SD) for the historical approach was 3.7° and for the ischio-lateral method, 2.2° (p < 0.001). With the historical method, 19 (36.5%) hips had a SD greater than ± 4°, compared to six hips (11.5%) with the ischio-lateral method. By using a skeletal reference, the ischio-lateral method provides a more consistent measurement of acetabular component position. The high intra-class correlation coefficients for both intra- and inter-observer reliability indicate that the angle measured with this simple method, which employs no further technology, increased time, or cost, is consistent and reproducible for multiple observers.
Reggiani, Matteo; Tinti, Anna; Visentin, Manuela; Stea, Susanna; Erani, Paolo; Fagnano, Concezio
Ultra-high-molecular-weight polyethylene (UHMWPE) has been used for over 40 years for acetabular cups in total hip joint prosthesis. Hylamer is a hot isostatically pressed material with high crystallinity. Early loosening due to extensive oxidation and phase transformation has been observed for this material. To analyze the reasons for its high tendency to oxidize, we have examined by FT-IR spectroscopy explanted acetabular cups γ-sterilized in different ways. The oxidation and wear rate observed were: Hylamer cups γ-sterilized in air with a long shelf life > Hylamer cups γ-sterilized in air with short shelf life ⩾ Hylamer cups γ-sterilized in nitrogen. Our data indicate the important role of the shelf life on the oxidation of the cups: the samples γ-sterilized in air characterized by a shelf life greater than 3 years showed severe oxidation, a high wear rate, and marked debris production with delamination and the formation of a brittle zone in the more oxidated regions. In these regions we observed an increase in crystallinity, which was probably due to the decrease in the molecular weight of PE. The high oxidation was probably due to the modifications induced by the material treatment.
This issue of Keying In, the newsletter of the National Business Education Association, focuses upon teaching young adults how to develop both investment strategies and an understanding of the stock market. The first article, "Sound Investing Know-How: A Must for Today's Young Adults," describes how young adults can plan for their own…
... soap. Do not use Woolite™ detergent. Use warm water and wash by hand or in the gentle cycle in the washing machine. After rinsing the compression stocking completely, remove excess water by rolling it in a ... the dryer on the deli- cate cycle at a cool temperature. It may be convenient ...
... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Hip joint metal/metal semi-constrained, with a... Devices § 888.3320 Hip joint metal/metal semi-constrained, with a cemented acetabular component, prosthesis. (a) Identification. A hip joint metal/metal semi-constrained, with a cemented...
... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Hip joint metal/metal semi-constrained, with an... Devices § 888.3330 Hip joint metal/metal semi-constrained, with an uncemented acetabular component, prosthesis. (a) Identification. A hip joint metal/metal semi-constrained, with an uncemented...
... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Hip joint metal/metal semi-constrained, with an... Devices § 888.3330 Hip joint metal/metal semi-constrained, with an uncemented acetabular component, prosthesis. (a) Identification. A hip joint metal/metal semi-constrained, with an uncemented...
... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Hip joint metal/metal semi-constrained, with a... Devices § 888.3320 Hip joint metal/metal semi-constrained, with a cemented acetabular component, prosthesis. (a) Identification. A hip joint metal/metal semi-constrained, with a cemented...
... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Hip joint metal/metal semi-constrained, with a... Devices § 888.3320 Hip joint metal/metal semi-constrained, with a cemented acetabular component, prosthesis. (a) Identification. A hip joint metal/metal semi-constrained, with a cemented...
... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Hip joint metal/metal semi-constrained, with a... Devices § 888.3320 Hip joint metal/metal semi-constrained, with a cemented acetabular component, prosthesis. (a) Identification. A hip joint metal/metal semi-constrained, with a cemented...
... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Hip joint metal/metal semi-constrained, with an... Devices § 888.3330 Hip joint metal/metal semi-constrained, with an uncemented acetabular component, prosthesis. (a) Identification. A hip joint metal/metal semi-constrained, with an uncemented...
... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Hip joint metal/metal semi-constrained, with an... Devices § 888.3330 Hip joint metal/metal semi-constrained, with an uncemented acetabular component, prosthesis. (a) Identification. A hip joint metal/metal semi-constrained, with an uncemented...
... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Hip joint metal/metal semi-constrained, with an... Devices § 888.3330 Hip joint metal/metal semi-constrained, with an uncemented acetabular component, prosthesis. (a) Identification. A hip joint metal/metal semi-constrained, with an uncemented...
... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Hip joint metal/metal semi-constrained, with a... Devices § 888.3320 Hip joint metal/metal semi-constrained, with a cemented acetabular component, prosthesis. (a) Identification. A hip joint metal/metal semi-constrained, with a cemented...
Safran, Marc R
The past decade has seen unprecedented growth in the number of hip arthroscopies. Acetabular labral tears are the leading indication for arthroscopy of this joint. However, labral anatomy and function, as well as the effects of labral tears and surgical outcomes, have only recently been studied. Labral tears may cause pain and microinstability of the hip joint. They also may increase friction within the joint, cartilage consolidation, and strain within the articular cartilage, thereby possibly resulting in accelerated degeneration of the joint. Partial labrectomy and labral repair are the current surgical options, and basic science data suggest that labral repairs can heal and subsequently restore function. However, a good, validated outcomes measure to adequately assess active patients with a painful nonarthritic hip is needed to determine the efficacy of such repair and aid in managing patient expectations.
Yu, A W; Duncan, J M; Daurka, J S; Lewis, A; Cobb, J
There are a number of challenges associated with the operative treatment of acetabular fractures. The approach used is often extensive, while operative time and perioperative blood loss can also be significant. With the proliferation of 3D printer technology, we present a fast and economical way to aid the operative planning of complex fractures. We used augmented stereoscopic 3D CT reconstructions to allow for an appreciation of the normal 3D anatomy of the pelvis on the fractured side and to use the models for subsequent intraoperative contouring of pelvic reconstruction plates. This leads to a reduction in the associated soft tissue trauma, reduced intraoperative time and blood loss, minimal handling of the plate, and reduced fluoroscopic screening times. We feel that the use of this technology to customize implants, plates, and the operative procedure to a patient's unique anatomy can only lead to improved outcomes.
Nasr, P; Yip, G; Scaife, J E; House, T; Thomas, S J; Harris, F; Owen, P J; Hull, P
Objective: Radiotherapy (RT) is effective in preventing heterotopic ossification (HO) around acetabular fractures requiring surgical reconstruction. We audited outcomes and estimated risks from RT prophylaxis, and alternatives of indometacin or no prophylaxis. Methods: 34 patients underwent reconstruction of acetabular fractures through a posterior approach, followed by a 8-Gy single fraction. The mean age was 44 years. The mean time from surgery to RT was 1.1 days. The major RT risk is radiation-induced fatal cancer. The International Commission on Radiological Protection (ICRP) method was used to estimate risk, and compared with a method (Trott and Kemprad) specifically for estimating RT risk for benign disease. These were compared with risks associated with indometacin and no prophylaxis. Results: 28 patients (82%) developed no HO; 6 developed Brooker Class I; and none developed Class II–IV HO. The ICRP method suggests a risk of fatal cancer in the range of 1 in 1000 to 1 in 10,000; the Trott and Kemprad method suggests 1 in 3000. For younger patients, this may rise to 1 in 2000; and for elderly patients, it may fall to 1 in 6000. The risk of death from gastric bleeding or perforation from indometacin is 1 in 180 to 1 in 900 in older patients. Without prophylaxis risk of death from reoperation to remove HO is 1 in 4000 to 1 in 30,000. Conclusion: These results are encouraging, consistent with much larger series and endorse our multidisciplinary management. Risk estimates can be used in discussion with patients. Advances in knowledge: The risk from RT prophylaxis is small, it is safer than indometacin and substantially overlaps with the range for no prophylaxis. PMID:25089852
Seagrave, Kurt G; Troelsen, Anders; Malchau, Henrik; Husted, Henrik; Gromov, Kirill
Background and purpose — Hip dislocation is one of the most common complications following total hip arthroplasty (THA). Several factors that affect dislocation have been identified, including acetabular cup positioning. Optimal values for cup inclination and anteversion are debatable. We performed a systematic review to describe the different methods for measuring cup placement, target zones for cup positioning, and the association between cup positioning and dislocation following primary THA. Methods — A systematic search of literature in the PubMed database was performed (January and February 2016) to identify articles that compared acetabular cup positioning and the risk of dislocation. Surgical approach and methods for measurement of cup angles were also considered. Results— 28 articles were determined to be relevant to our research question. Some articles demonstrated that cup positioning influenced postoperative dislocation whereas others did not. The majority of articles could not identify a statistically significant difference between dislocating and non-dislocating THA with regard to mean angles of cup anteversion and inclination. Most of the articles that assessed cup placement within the Lewinnek safe zone did not show a statistically significant reduction in dislocation rate. Alternative target ranges have been proposed by several authors. Interpretation— The Lewinnek safe zone could not be justified. It is difficult to draw broad conclusions regarding a definitive target zone for cup positioning in THA, due to variability between studies and the likely multifactorial nature of THA dislocation. Future studies comparing cup positioning and dislocation rate should investigate surgical approach separately. Standardized tools for measurement of cup positioning should be implemented to allow comparison between studies. PMID:27879150
The paper presents an evolutionary economic model for the price evolution of stocks. Treating a stock market as a self-organized system governed by a fast purchase process and slow variations of demand and supply the model suggests that the short term price distribution has the form a logistic (Laplace) distribution. The long term return can be described by Laplace-Gaussian mixture distributions. The long term mean price evolution is governed by a Walrus equation, which can be transformed into a replicator equation. This allows quantifying the evolutionary price competition between stocks. The theory suggests that stock prices scaled by the price over all stocks can be used to investigate long-term trends in a Fisher-Pry plot. The price competition that follows from the model is illustrated by examining the empirical long-term price trends of two stocks.
... 12 Banks and Banking 10 2014-01-01 2014-01-01 false Stock purchase. 1263.20 Section 1263.20 Banks and Banking FEDERAL HOUSING FINANCE AGENCY FEDERAL HOME LOAN BANKS MEMBERS OF THE BANKS Stock Requirements § 1263.20 Stock purchase. (a) Minimum stock purchase. Each member shall purchase stock in the...
... 12 Banks and Banking 7 2010-01-01 2010-01-01 false Excess stock. 925.23 Section 925.23 Banks and... BANKS Stock Requirements § 925.23 Excess stock. (a) Sale of excess stock. Subject to the restriction in paragraph (b) of this section, a member may purchase excess stock as long as the purchase is approved by...
... 12 Banks and Banking 9 2013-01-01 2013-01-01 false Stock purchase. 1263.20 Section 1263.20 Banks and Banking FEDERAL HOUSING FINANCE AGENCY FEDERAL HOME LOAN BANKS MEMBERS OF THE BANKS Stock Requirements § 1263.20 Stock purchase. (a) Minimum stock purchase. Each member shall purchase stock in the...
... 12 Banks and Banking 9 2012-01-01 2012-01-01 false Stock purchase. 1263.20 Section 1263.20 Banks and Banking FEDERAL HOUSING FINANCE AGENCY FEDERAL HOME LOAN BANKS MEMBERS OF THE BANKS Stock Requirements § 1263.20 Stock purchase. (a) Minimum stock purchase. Each member shall purchase stock in the...
... 12 Banks and Banking 7 2011-01-01 2011-01-01 false Stock purchase. 1263.20 Section 1263.20 Banks and Banking FEDERAL HOUSING FINANCE AGENCY FEDERAL HOME LOAN BANKS MEMBERS OF THE BANKS Stock Requirements § 1263.20 Stock purchase. (a) Minimum stock purchase. Each member shall purchase stock in the...
... 12 Banks and Banking 7 2010-01-01 2010-01-01 false Stock purchase. 925.20 Section 925.20 Banks and... BANKS Stock Requirements § 925.20 Stock purchase. (a) Minimum stock purchase. Each member shall purchase stock in the Bank in which it is a member in an amount equal to the greater of: (1) $500; (2) 1...
Mormor, Meir; Matityahu, Amir
This article presents a case of a 10-year-old boy with a right acetabular fracture secondary to a direct blow to the pelvis and back. He sustained a right hip dislocation and transverse with posterior wall acetabular fracture with a nonconcentric hip joint after reduction. The fracture was treated with right labral and articular segment absorbable suture tie-down and relocation of the right hip into an anatomical position. At 32-month follow-up, the patient had returned to activities of daily living, he had a normal and symmetric gait pattern, and no pain on hip adduction, flexion, or internal rotation. This technique reduced the fracture and labrum, relocated the hip joint, and obviated the need for hardware removal that is typically needed in the pediatric population. This case is distinctive due to the patient's young age and treatment method, which has not been described previously for the treatment of this rare pediatric fracture.
Eskildsen, Scott M; Olsson, Erik C; Del Gaizo, Daniel J
A 75-year-old woman who suffered a left femoral neck fracture underwent a left total hip arthroplasty using a Stryker Trident (Kalamazoo, MI) hemispherical acetabular shell and Modular Dual Mobility (MDM) metal liner. Post-operative radiographs demonstrated canted seating of the liner. The patient was taken immediately back to the operating room where the acetabular liner appeared well seated superiorly but was in a canted position inferiorly. Removal and replacement was performed and post-operative radiographs demonstrated complete seating. Subsequent follow up at 6 months demonstrated good clinical function with no adverse radiographic findings. Canted seating is a potential complication of the MDM metal liner. Providers should be aware of potential incomplete seating inferiorly despite the superior portion of the liner being well seated.
Anderson, Brian C; Bloom, Paul D; Baikerikar, K G; Sheares, Valerie V; Mallapragada, Surya K
Polymer composites of Al-Cu-Fe quasicrystals and ultra-high molecular weight polyethylene (UHMWPE) were investigated for use in acetabular cup prosthetics. The wear properties of the Al-Cu-Fe/UHMWPE samples and a 440 steel ball counterface were measured. The mechanical strength of the Al-Cu-Fe/UHMWPE composites was compared to UHMWPE and alumina/UHMWPE. The biocompatibility of the composite material was tested using a direct contact cytotoxicity assay. Al-Cu-Fe/UHMWPE demonstrated lower volume loss after wear and higher mechanical strength than UHMWPE. This composite material also showed no increase in counterface wear or cytotoxicity relative to UHMWPE. These combined results demonstrate that Al-Cu-Fe/UHMWPE composites are promising candidate materials for acetabular cup prosthetics.
Korduba, Laryssa A; Essner, Aaron; Pivec, Robert; Lancin, Perry; Mont, Michael A; Wang, Aiguo; Delanois, Ronald E
The effect of acetabular component positioning on the wear rates of metal-on-polyethylene articulations has not been extensively studied. Placement of acetabular cups at abduction angles of more than 40° has been noted as a possible reason for early failure caused by increased wear. We conducted a study to evaluate the effects of different acetabular cup abduction angles on polyethylene wear rate, wear area, contact pressure, and contact area. Our in vitro study used a hip joint simulator and finite element analysis to assess the effects of cup orientation at 4 angles (0°, 40°, 50°, 70°) on wear and contact properties. Polyethylene bearings with 28-mm cobalt-chrome femoral heads were cycled in an environment mimicking in vivo joint fluid to determine the volumetric wear rate after 10 million cycles. Contact pressure and contact area for each cup abduction angle were assessed using finite element analysis. Results were correlated with cup abduction angles to determine if there were any differences among the 4 groups. The inverse relationship between volumetric wear rate and acetabular cup inclination angle demonstrated less wear with steeper cup angles. The largest abduction angle (70°) had the lowest contact area, largest contact pressure, and smallest head coverage. Conversely, the smallest abduction angle (0°) had the most wear and most head coverage. Polyethylene wear after total hip arthroplasty is a major cause of osteolysis and aseptic loosening, which may lead to premature implant failure. Several studies have found that high wear rates for cups oriented at steep angles contributed to their failure. Our data demonstrated that larger cup abduction angles were associated with lower, not higher, wear. However, this potentially "protective" effect is likely counteracted by other complications of steep cup angles, including impingement, instability, and edge loading. These factors may be more relevant in explaining why implants fail at a higher rate if
Zhang, Lihai; Zhang, Wei; Li, Tongtong; Li, Jiantao; Chen, Hua
Objective. The objective of this study was to evaluate the effectiveness and advantages of percutaneous fixation of anterior column acetabular fracture with “hammering technique.” Materials and Methods. We retrospectively reviewed 16 patients with percutaneous fixation of anterior column acetabular fracture with “hammering technique.” There were 11 males and 5 females with an average age of 38.88 years (range: 24–54 years) in our study. Our study included 7 nondisplaced fractures, 6 mild displaced fractures (<2 mm), and 5 displaced fractures (>2 mm). The mean time from injury to surgery was 4.5 days (range: 2–7 days). Results. The average of operation time was 27.56 minutes (range: 15–45 minutes), and the mean blood loss was 55.28 mL (range: 15–100 mL). The mean fluoroscopic time was 54.78 seconds (range: 40–77 seconds). The first pass of the guide wire was acceptable without cortical perforation or intra-articular perforation in 88.89% (16/18) of the procedures, and the second attempt was in 11.11% (2/18). Conclusion. Our study suggested that percutaneous fixation of anterior column acetabular fracture with “hammering technique” acquired satisfying surgical and clinical outcomes. It may be an alternative satisfying treatment for percutaneous fixation of anterior column acetabular fracture by 2D fluoroscopy using a C-arm with less fluoroscopic time. PMID:27493962
Bonneau, Noémie; Bouhallier, July; Baylac, Michel; Tardieu, Christine; Gagey, Olivier
Understanding the three-dimensional orientation of the coxo-femoral joint remains a challenge as an accurate three-dimensional orientation ensure an efficient bipedal gait and posture. The quantification of the orientation of the acetabulum can be performed using the three-dimensional axis perpendicular to the plane that passes along the edge of the acetabular rim. However, the acetabular rim is not regular as an important indentation in the anterior rim was observed. An innovative cadaver study of the labrum was developed to shed light on the proper quantification of the three-dimensional orientation of the acetabulum. Dissections on 17 non-embalmed corpses were performed. Our results suggest that the acetabular rim is better represented by an anterior plane and a posterior plane rather than a single plane along the entire rim as it is currently assumed. The development of the socket from the Y-shaped cartilage was suggested to explain the different orientations in these anterior and posterior planes. The labrum forms a plane that takes an orientation in between the anterior and posterior parts of the acetabular rim, filling up inequalities of the bony rim. The vectors VL, VA2 and VP, representing the three-dimensional orientation of the labrum, the anterior rim and the posterior rim, are situated in a unique plane that appears biomechanically dependent. The three-dimensional orientation of the acetabulum is a fundamental parameter to understand the hip joint mechanism. Important applications for hip surgery and rehabilitation, as well as for physical anthropology, were discussed. PMID:22360458
... 17 Commodity and Securities Exchanges 3 2010-04-01 2010-04-01 false Stock splits, stock dividends... Government Securities Dealers § 240.16a-9 Stock splits, stock dividends, and pro rata rights. The following... held as a result of a stock split or stock dividend applying equally to all securities of a...
... 17 Commodity and Securities Exchanges 3 2013-04-01 2013-04-01 false Stock splits, stock dividends... Government Securities Dealers § 240.16a-9 Stock splits, stock dividends, and pro rata rights. The following... held as a result of a stock split or stock dividend applying equally to all securities of a...
... 17 Commodity and Securities Exchanges 3 2012-04-01 2012-04-01 false Stock splits, stock dividends... Government Securities Dealers § 240.16a-9 Stock splits, stock dividends, and pro rata rights. The following... held as a result of a stock split or stock dividend applying equally to all securities of a...
... 17 Commodity and Securities Exchanges 4 2014-04-01 2014-04-01 false Stock splits, stock dividends... Government Securities Dealers § 240.16a-9 Stock splits, stock dividends, and pro rata rights. The following... held as a result of a stock split or stock dividend applying equally to all securities of a...
... 17 Commodity and Securities Exchanges 3 2011-04-01 2011-04-01 false Stock splits, stock dividends... Government Securities Dealers § 240.16a-9 Stock splits, stock dividends, and pro rata rights. The following... held as a result of a stock split or stock dividend applying equally to all securities of a...
In this classroom activity, engineering, nutrition, and physical activity collide when students design and build a healthy bone model of a space explorer which is strong enough to withstand increas...
Pedersen, D. R.; Brown, T. D.; Maxian, T. A.; Callaghan, J. J.
The motions of counterface articulation against the bearing surface of the acetabular liner strongly influence polyethylene wear debris production in contemporary total hip arthroplasty. However, the available body of relevant articular force and motion information is largely confined to resultant load excursions measured relative to instrumented femoral components, and/or to global angular motions (flexion, adduction, endorotation) of the joint. Analytical frameworks are here developed to transform such information into temporal and spatial variations of the resultant load and of the local counterface sliding velocity relative to an ordered set of discrete locations (e.g., finite element nodes) on the acetabular bearing surface. Whole-duty-cycle time histories of acetabular resultant load and counterface velocity distributions are presented for two important practical situations: human level walking gait, and a 23 degrees biaxial rocking hip simulation machine. The local counterface motions occurring in the simulator are characterized by higher velocities, smoother motion patterns, and wider directional variation than those occurring in human gait. PMID:9807707
Cancer that starts in a bone is uncommon. Cancer that has spread to the bone from another ... more common. There are three types of bone cancer: Osteosarcoma - occurs most often between ages 10 and ...
Your bones help you move, give you shape and support your body. They are living tissues that rebuild constantly ... childhood and your teens, your body adds new bone faster than it removes old bone. After about ...
... metastasis, surgeons can stabilize the bone using metal plates, screws and nails (orthopedic fixation). Orthopedic fixation can ... that can't be easily reinforced with metal plates or screws, such as pelvic bones and bones ...
Bu, Luping; Shang, Pengjian
In this paper, we apply the detrended fluctuation analysis (DFA), local scaling detrended fluctuation analysis (LSDFA), and detrended cross-correlation analysis (DCCA) to investigate correlations of several stock markets. DFA method is for the detection of long-range correlations used in time series. LSDFA method is to show more local properties by using local scale exponents. DCCA method is a developed method to quantify the cross-correlation of two non-stationary time series. We report the results of auto-correlation and cross-correlation behaviors in three western countries and three Chinese stock markets in periods 2004-2006 (before the global financial crisis), 2007-2009 (during the global financial crisis), and 2010-2012 (after the global financial crisis) by using DFA, LSDFA, and DCCA method. The findings are that correlations of stocks are influenced by the economic systems of different countries and the financial crisis. The results indicate that there are stronger auto-correlations in Chinese stocks than western stocks in any period and stronger auto-correlations after the global financial crisis for every stock except Shen Cheng; The LSDFA shows more comprehensive and detailed features than traditional DFA method and the integration of China and the world in economy after the global financial crisis; When it turns to cross-correlations, it shows different properties for six stock markets, while for three Chinese stocks, it reaches the weakest cross-correlations during the global financial crisis.
U.S. corporations do not issue and repurchase debt and equity to counteract the mechanistic effects of stock returns on their debt-equity ratios. Thus over one- to five-year horizons, stock returns can explain about 40 percent of debt ratio dynamics. Although corporate net issuing activity is lively and although it can explain 60 percent of debt…
Kallestrup, Lisbeth; Søgaard, Tine; Schjødt, Inge; Grove, Erik Lerkevang
Post-thrombotic syndrome (PTS) is caused by venous insufficiency and is a frequent complication of deep venous thrombosis. Patients with PTS have reduced quality of life and an increased risk of recurrent deep venous thrombosis. Importantly, the risk of PTS is halved by the use of elastic compression stockings. This review outlines important practical aspects related to correct clinical use of these stockings.
Luo, Jiawen; Chen, Langnan; Liu, Hao
We examine the distribution characteristics of stock market liquidity by employing the generalized additive models for location, scale and shape (GAMLSS) model and three-minute frequency data from Chinese stock markets. We find that the BCPE distribution within the GAMLSS framework fits the distributions of stock market liquidity well with the diagnosis test. We also find that the stock market index exhibits a significant impact on the distributions of stock market liquidity. The stock market liquidity usually exhibits a positive skewness, but a normal distribution at a low level of stock market index and a high-peak and fat-tail shape at a high level of stock market index.
Gordon, R. B.; Bertram, M.; Graedel, T. E.
The relative proportions of metal residing in ore in the lithosphere, in use in products providing services, and in waste deposits measure our progress from exclusive use of virgin ore toward full dependence on sustained use of recycled metal. In the U.S. at present, the copper contents of these three repositories are roughly equivalent, but metal in service continues to increase. Providing today's developed-country level of services for copper worldwide (as well as for zinc and, perhaps, platinum) would appear to require conversion of essentially all of the ore in the lithosphere to stock-in-use plus near-complete recycling of the metals from that point forward. PMID:16432205
Crofton, Patricia M
Children with cancer are exposed to multiple influences that may adversely affect bone health. Some treatments have direct deleterious effects on bone whilst others may have indirect effects mediated through various endocrine abnormalities. Most clinical outcome studies have concentrated on survivors of acute lymphoblastic leukaemia (ALL). There is now good evidence that earlier treatment protocols that included cranial irradiation with doses of 24 Gy or greater may result in growth hormone deficiency and low bone mineral density (BMD) in the lumbar spine and femoral neck. Under current protocols, BMD decreases during intensive chemotherapy and fracture risk increases. Although total body BMD may eventually return to normal after completion of chemotherapy, lumbar spine trabecular BMD may remain low for many years. The implications for long-term fracture risk are unknown. Risk factors for low BMD include high dose methotrexate, higher cumulative doses of glucocorticoids, male gender and low physical activity. BMD outcome in non-ALL childhood cancers has been less well studied but there is evidence that survivors of childhood brain or bone tumours, and survivors of bone marrow transplants for childhood malignancy, all have a high risk of long-term osteopenia. Long-term follow-up is required, with appropriate treatment of any endocrine abnormalities identified.
Kosuge, D; Cordier, T; Solomon, L B; Howie, D W
Peri-acetabular osteotomy is an established surgical treatment for symptomatic acetabular dysplasia in young adults. An anteroposterior radiograph of the pelvis is commonly used to assess the extent of dysplasia as well as to assess post-operative correction. Radiological prognostic factors include the lateral centre-edge angle, acetabular index, extrusion index and the acetabular version. Standing causes a change in the pelvis tilt which can alter certain radiological measurements relative to the supine position. This article discusses the radiological indices used to assess dysplasia and reviews the effects of patient positioning on these indices with a focus on assessment for a peri-acetabular osteotomy. Intra-operatively, fluoroscopy is commonly used and the implications of using fluoroscopy as a modality to assess the various radiological indices along with the effects of using an anteroposterior or posteroanterior fluoroscopic view are examined. Each of these techniques gives rise to a slightly different image of the pelvis as the final image is sensitive to the position of the pelvis and the projection of the x-ray beam.
Liu, Xinwei; Xu, Shuogui; Su, Jiacan; Yu, Baoqing
Displaced acetabular fractures should be treated surgically. Over the past decade, surgical approaches to the acetabulum and the surgical technique for repair of common fracture patterns have advanced. Excellent outcomes after repair of these injuries can be achieved. The aim of this study was to assess the medium-term results of reconstruction of acetabular fractures by using shape-memory alloy designed by the authors. This is a retrospective review conducted at a level 1 trauma centre. From October 1999 to July 2009, 19 patients with acetabular fractures were treated with our patented Ni-Ti shape-memory alloy acetabular tridimensional memory alloy-fixation system (ATMFS). The ATMFS device was cooled with ice before implantation and then warmed to 40–50°C after implantation to produce balanced axial and compression forces that would stabilise the fracture three dimensionally. Our results are as follows; according to the D’Aubigne−Postel scoring system: Fifteen cases out of 19 (79%) achieved excellent or good clinical results. In two patients, late complications included avascular necrosis of the femoral head (ANFH) associated with posterior dislocation of the hip joint two years after the operation. We also observed two cases of grade II or III ectopic ossification, with good hip function, and one case of traumatic arthritis. In conclusion, these results demonstrate the effectiveness of the ATMFS device for the management of acetabular fracture. The device provides continuous compression of the fracture with minimal disruption to the local blood supply. PMID:20012433
Fernández-Valencia, Jenaro Ángel; Gallart, Xavier; Bori, Guillem; Rodríguez-Roiz, Juan Miguel; Combalia, Andreu
A retrospective study was performed to evaluate the cement mantle in two groups of patients treated with the acetabular components of cemented Exeter total hip arthroplasties (THAs). Two groups of 20 patients were compared: Group 1 received non-flanged acetabular cemented cups (Contemporary, Stryker) and Group 2 received flanged acetabular cemented cups (X3 Rim Fit, Stryker). Cups in Group 2 were implanted after using a rim cutter device. Group 2 showed better penetration of cement in zone 1 (10.76 mm compared with 2.93 mm; p = 0.008) and a thicker cement mantle in zone 1 (3.57 mm compared with 2.89 mm; p = 0.04). More cups in Group 2 had a cement mantle thickness less than 3 mm (30 % in Group 1 compared with 70 % in Group 2; p = 0.0039). No other radiological differences were observed. These results favor the use of a rim cutter device and flanged cup to improve the cement mantle for the acetabular components of cemented Exeter THAs. However, the improvements were less than expected. In view of the results of previous studies, further research is therefore needed to assess the value of this approach in improving the acetabular cement mantle.
Khorasani, M T; Zaghiyan, M; Mirzadeh, H
An acetabular cup shock absorber implant is formed from a composite of polymer materials. The cup consists of three zones such as the articulating surface of the implant is 100% ultra high molecular weight polyethylene (UHMWPE) (zone 1) and shock absorber of the cup contains of polydimethylsiloxane (PDMS) (zone 3). Zone 2 which is designed for better adhesion between zone 1 and zone 2 consists of a blend of UHMWPE and PDMS is a cushion that from one side adheres to zone 1 and the other side to zone 2. PDMS and UHMWPE have been blended under conditions of shear and elevated temperature in order to form uniform, thermoplastic blends. When blends compared to pure UHMWPE, the blends show lowered tensile modulus and lowered mixing energies. The UHMWPE crystals are increased in quantity or else become more regular, even 50% blend shows no rubbery stage. The morphology and dynamic mechanical behavior of the blends were studied using scanning electron microscopy (SEM) and dynamic mechanic thermal analysis (DMTA). In this study, the biocompatibility have evaluated in vitro the interaction of UHMWPE, silicone and PDMS/UHMWPE blends with L929 fibroblast cells.
Dearden, Paul M; Bobak, Peter P; Giannoudis, Peter V
With an ageing population, and increasing longevity of hip arthroplasty prostheses, the incidence of periprosthetic femoral fractures is rising. We present a simple and easily reproducible technique for reduction of any periprosthetic fracture that requires bone graft augmentation. This method facilitates impaction bone grafting to reconstitute lost bone stock and revision using a cemented implant.
... 12 Banks and Banking 9 2013-01-01 2013-01-01 false Excess stock. 1263.23 Section 1263.23 Banks and Banking FEDERAL HOUSING FINANCE AGENCY FEDERAL HOME LOAN BANKS MEMBERS OF THE BANKS Stock Requirements § 1263.23 Excess stock. (a) Sale of excess stock. Subject to the restriction in paragraph (b) of...
... 12 Banks and Banking 7 2011-01-01 2011-01-01 false Excess stock. 1263.23 Section 1263.23 Banks and Banking FEDERAL HOUSING FINANCE AGENCY FEDERAL HOME LOAN BANKS MEMBERS OF THE BANKS Stock Requirements § 1263.23 Excess stock. (a) Sale of excess stock. Subject to the restriction in paragraph (b) of...
... 12 Banks and Banking 7 2012-01-01 2012-01-01 false Capital stock. 725.5 Section 725.5 Banks and... ADMINISTRATION CENTRAL LIQUIDITY FACILITY § 725.5 Capital stock. (a) The capital stock of the Facility is divided... or hypothecated except to the Facility. (b) The capital stock subscriptions provided for in §§...
... 12 Banks and Banking 10 2014-01-01 2014-01-01 false Excess stock. 1263.23 Section 1263.23 Banks and Banking FEDERAL HOUSING FINANCE AGENCY FEDERAL HOME LOAN BANKS MEMBERS OF THE BANKS Stock Requirements § 1263.23 Excess stock. (a) Sale of excess stock. Subject to the restriction in paragraph (b)...
... 12 Banks and Banking 7 2014-01-01 2014-01-01 false Capital stock. 725.5 Section 725.5 Banks and... ADMINISTRATION CENTRAL LIQUIDITY FACILITY § 725.5 Capital stock. (a) The capital stock of the Facility is divided... or hypothecated except to the Facility. (b) The capital stock subscriptions provided for in §§...
... 12 Banks and Banking 7 2013-01-01 2013-01-01 false Capital stock. 725.5 Section 725.5 Banks and... ADMINISTRATION CENTRAL LIQUIDITY FACILITY § 725.5 Capital stock. (a) The capital stock of the Facility is divided... or hypothecated except to the Facility. (b) The capital stock subscriptions provided for in §§...
... 12 Banks and Banking 6 2011-01-01 2011-01-01 false Capital stock. 725.5 Section 725.5 Banks and... ADMINISTRATION CENTRAL LIQUIDITY FACILITY § 725.5 Capital stock. (a) The capital stock of the Facility is divided... or hypothecated except to the Facility. (b) The capital stock subscriptions provided for in §§...
... 12 Banks and Banking 9 2012-01-01 2012-01-01 false Excess stock. 1263.23 Section 1263.23 Banks and Banking FEDERAL HOUSING FINANCE AGENCY FEDERAL HOME LOAN BANKS MEMBERS OF THE BANKS Stock Requirements § 1263.23 Excess stock. (a) Sale of excess stock. Subject to the restriction in paragraph (b) of...
Provides two computer programs, written in BASIC, to calculate average stock market price levels. The programs allow students to work directly from the raw price data that appear daily in the financial news. Teaching suggestions are provided. (JDH)
Balogh, Emeric; Simonsen, Ingve; Nagy, Bálint Zs.; Néda, Zoltán
Empirical evidence is given for a significant difference in the collective trend of the share prices during the stock index rising and falling periods. Data on the Dow Jones Industrial Average and its stock components are studied between 1991 and 2008. Pearson-type correlations are computed between the stocks and averaged over stock pairs and time. The results indicate a general trend: whenever the stock index is falling the stock prices are changing in a more correlated manner than in case the stock index is ascending. A thorough statistical analysis of the data shows that the observed difference is significant, suggesting a constant fear factor among stockholders.
... 12 Banks and Banking 3 2010-01-01 2010-01-01 false Extension of credit in certain stock option and... Extension of credit in certain stock option and stock purchase plans. Questions have been raised as to whether certain stock option and stock purchase plans involve extensions of credit subject to this...
Iliac crest tap; Sternal tap; Leukemia - bone marrow aspiration; Aplastic anemia - bone marrow aspiration; Myelodysplastic syndrome - bone marrow aspiration; Thrombocytopenia - bone marrow aspiration; Myelofibrosis - bone marrow aspiration
Takahashi, Yasuhito; Tateiwa, Toshiyuki; Shishido, Takaaki; Masaoka, Toshinori; Kubo, Kosuke; Yamamoto, Kengo
The in-vivo progression of creep and wear in ultra-high molecular weight polyethylene (UHMWPE) acetabular liners has been clinically evaluated by measuring radiographic penetration of femoral heads. In such clinical assessments, however, viscoelastic strain relaxation has been rarely considered after a removal of hip joint loading, potentially leading to an underestimation of the penetrated thickness. The objective of this study was to investigate shape-recovery behavior of pre-compressed, radiation crosslinked and antioxidant vitamin E-diffused UHMWPE acetabular liners, and also to characterize the effects of varying their internal diameter (ID) and wall thickness (WT). We applied uniaxial compression to the UHMWPE specimens of various ID (28, 32, 36mm) and WT (4.8, 6.8, 8.9mm) for 4320min under the constant load of 3000N, and subsequently monitored the strain-relaxation behavior as a function of time after unloading. It was observed that there was a considerable shape recovery of the components after removal of the external static load. Reducing ID and WT significantly accelerated the rate of creep strain recovery, and varying WT was more sensitive to the recovery behavior than ID. Creep deformation of the tested liners recovered mostly within the first 300min after unloading. Note that approximately half of the total recovery amount proceeded just within 5min after unloading. These results suggest a remarkably high capability of shape recovery of vitamin E-diffused highly crosslinked UHMWPE. In conclusion, the time-dependent shape recovering and the diameter-thickness effect on its behavior should be carefully considered when the postoperative penetration is quantified in highly crosslinked UHMWPE acetabular liners (especially on the non-weight bearing radiographs).
Caravia, L; Dowson, D; Fisher, J; Jobbins, B
Studies of explanted hip prostheses have shown high wear rates of ultra-high molecular weight polyethylene (UHMWPE) acetabular cups and roughening of the surface of the metallic femoral head. Bone and bone cement particles have also been found in the articulating surfaces of some joints. It has been proposed that bone or bone cement particles may cause scratching and deterioration in the surface finish of metallic femoral heads, thus producing increased wear rates and excessive amounts of wear debris. Sliding wear tests of UHMWPE pins on stainless steel have been performed with particles of different types of bone and bone cement added. Damage to the stainless steel counterface and the motion of particles through the interface have been studied. Particles of bone cement with zirconium and barium sulphate additives and particles of cortical bone scratched the stainless steel counterface. The cement particles with zirconium additive produced significantly greater surface damage. The number of particles entering the contact and embedding in the UHMWPE pin was dependent on particle size and geometry, surface roughness and contact stress. Particles are likely to cause surface roughening and increased wear rates in artificial joints.
Malviya, A; Dandachli, W; Beech, Z; Bankes, M J; Witt, J D
Stress fractures occurring in the pubis and ischium after peri-acetabular osteotomy (PAO) are not well recognised, with a reported incidence of 2% to 3%. The purpose of this study was to analyse the incidence of stress fracture after Bernese PAO under the care of two high-volume surgeons. The study included 359 patients (48 men, 311 women) operated on at a mean age of 31.1 years (15 to 56), with a mean follow-up of 26 months (6 to 64). Complete follow-up radiographs were available for 348 patients, 64 of whom (18.4%) developed a stress fracture of the inferior pubic ramus, which was noted at a mean of 9.1 weeks (5 to 55) after surgery. Most (58; 91%) healed. In 40 of the patients with a stress fracture (62.5%), pubic nonunion also occurred. Those with a stress fracture were significantly older (mean 33.9 years (16 to 50) vs 30.5 years (15 to 56), p = 0.002) and had significantly more mean pre-operative deformity: mean centre-edge angle (9.8° (-9.5 to 35) vs 12.4° (-33 to 28), p = 0.04) and mean Tönnis angle (22.8° (0 to 45) vs 18.7° (-2 to 38), p < 0.001). The pubic nonunion rate was significantly higher in those with a stress fracture (62.5% vs 7%, p < 0.001), with regression analysis revealing that these patients had 11.8 times higher risk than those without nonunion.
Zivkovic, I; Gonzalez, M; Amirouche, F
This paper explores the effect of under-reaming on micromotion at the cup/bone interface of a press-fit acetabular cup. A cadaver experiment was performed on 11 acetabuli implanted with a cementless acetabular cup. The loading profile simulated hip impingement at the extremes of motion and subluxation relocation of the hip joint. Micromotion of each cup was measured in a custom made jig with linear variable differential transducers. A CAT scan and DEXA scan of the acetabulum and femoral head respectively were used to construct a three-dimensional patient specific finite element model of the hemi-pelvis. The model predicted cup micromotion under loading conditions and stresses in the acetabulum as a result of cup insertion. Micromotion was then calculated as a function of variable bone density and variable degree of underreaming. Simulated cup insertion with under-reaming of 2 mm or more approached or exceeded the yield strength of bone in acetabula with reduced bone mass density.
... Mayo Clinic Staff A bone scan is a nuclear imaging test that helps diagnose and track several ... you're nursing. A bone scan is a nuclear imaging procedure. In nuclear imaging, tiny amounts of ...
Hubble, Matthew J W
Bone grafts are used in musculoskeletal surgery to restore structural integrity and enhance osteogenic potential. The demand for bone graft for skeletal reconstruction in bone tumor, revision arthroplasty, and trauma surgery, couple with recent advances in understanding and application of the biology of bone transplantation, has resulted in an exponential increase in the number of bone-grafting procedures performed over the last decade. It is estimated that 1.5 million bone-grafting procedures are currently performed worldwide each year, compared to a fraction of that number 20 years ago. Major developments also have resulted in the harvesting, storage, and use of bone grafts and production of graft derivatives, substitutes, and bone-inducing agents.
Vaishya, Raju; Chauhan, Mayank; Vaish, Abhishek
The knowledge about the bone cement is of paramount importance to all Orthopaedic surgeons. Although the bone cement had been the gold standard in the field of joint replacement surgery, its use has somewhat decreased because of the advent of press-fit implants which encourages bone in growth. The shortcomings, side effects and toxicity of the bone cement are being addressed recently. More research is needed and continues in the field of nanoparticle additives, enhanced bone–cement interface etc. PMID:26403875
The danger of disuse osteoporosis under weightless condition in space led to extensive research into measurements of bone stiffness and mass by the Biomedical Research Division of Ames and Stanford University. Through its Technology Utilization Program, NASA funded an advanced SOBSA, a microprocessor-controlled bone probe system. SOBSA determines bone stiffness by measuring responses to an electromagnetic shaker. With this information, a physician can identify bone disease, measure deterioration and prescribe necessary therapy. The system is now undergoing further testing.
... bloodstream. People who are at risk for bone infections include those with diabetes, poor circulation, or recent injury to the bone. You may also be at risk if you are having hemodialysis. Symptoms of bone infections include Pain in the infected area Chills and ...
Xu, Meng; Qu, Wenrui; Wang, Yanbing; Zhong, Lei; Zhu, Zhe; Li, Wei; Zhao, Xin; Wang, Jincheng; Sun, Yu
Background Different extents and locations of acetabular cartilage defect have been supposed to be a major cause of undesirable outcomes of periacetabular osteotomy (PAO) in patients with developmental dysplasia of the hip (DDH). This study aimed to verify whether different locations of cartilage deficiency affect the biomechanical environment in a three-dimensional model utilizing finite element analysis (FEA). Material/Methods We developed 3 DDH models – DDH-1 (normal shape), DDH-2 (superior defect), and DDH-3 (anterosuperior defect) – by deforming from a normal hip model. We also developed 3 PAO models – PAO-1, PAO-2, and PAO-3 – through rotating osteotomized fragments. Results The maximum von Mises stress in the normal hip was 13.06 MPa. In the DDH-1 model, the maximum value on the load-bearing area decreased from 15.49 MPa pre-PAO to 14.28 MPa post-PAO, while stresses in the DDH-2 and DDH-3 models were higher than in the DDH-1 model, both pre-PAO and post-PAO (30.46 MPa to 26.04 MPa for DDH-2; 33.89 MPa to 27.48 MPa for DDH-3). Conclusions This study shows that, both pre- and post-PAO, different types of cartilage deficiency affect the biomechanical environment. Furthermore, in dysplastic hips, obtaining accurate three-dimensional information about the acetabular cartilage can contribute substantially to PAO decision making. PMID:28017958
Mendis, M Dilani; Wilson, Stephen J; Hayes, David A; Watts, Mark C; Hides, Julie A
Acetabular labral tears are a source of hip pain and are considered to be a precursor to hip osteoarthritis. Hip flexor muscles contribute to hip joint stability and function but it is unknown if their size and function is altered in the presence of labral pathology. This study aimed to investigate hip flexor muscle size, strength and recruitment pattern in patients with hip labral pathology compared to control subjects. 12 subjects diagnosed with an unilateral acetabular labral tear were compared to 12 control subjects matched for age and gender. All subjects underwent magnetic resonance imaging (MRI) of their lumbo-pelvic region. Average muscle cross-sectional area (CSA) of the iliacus, psoas, iliopsoas, sartorius, tensor fascia latae and rectus femoris muscles were measured. Hip flexion strength was measured by an externally fixed dynamometer. Individual muscle recruitment pattern during a resisted hip flexion exercise task was measured by muscle functional MRI. Hip flexor muscle strength was found to be decreased in patients with labral pathology compared to control subjects (p < 0.01). No difference between groups or sides was found for hip flexor muscle size (all p > 0.17) and recruitment pattern (all p > 0.53). Decreased hip flexor muscle strength may affect physical function in patients with hip labral pathology by contributing to altered gait patterns and functional tasks. Clinical rehabilitation of these patients may need to include strengthening exercises for the hip flexor muscles.
Kawano, Shunsuke; Sonohata, Motoki; Kitajima, Masaru; Mawatari, Masaaki
Liner dissociation of polyethylene from a cementless acetabular socket following total hip arthroplasty (THA) is a rare complication. Cross-linked polyethylene liner dissociation from AMS-HA shell (KYOCERA Med, Osaka, Japan) occurred in 2 out of the 4153 (0.04%) cases approximately 10 years after undergoing surgery at our institute. First case was an 80-year-old female who underwent right THA along with subtrochanteric femoral shortening osteotomy due to complete dislocation hip, and second case was a 72-year-old male, who underwent right THA due to coxarthrosis. A 26 mm femoral head and CPE liner were used in both cases and the inclination degree of the acetabular socket was within 50Â°.There was no implant loosening in both cases. There was partial damage in the elevated rim on the alternative side and scratches on the back side in the both extracted CPE liner. It was surmised that liner dissociation was caused due to a problem in the liner fixing format of the push in type of the present model. PMID:28217197
Teeter, Matthew G; Naudie, Douglas D R; Charron, Kory D; Holdsworth, David W
There is currently considerable interest in the use of highly cross-linked polyethylene (XLPE) acetabular liners for total hip arthroplasty (THA). In literature, only a single retrieval analysis of one type of XLPE liner implanted for greater than four years exists. The purpose of the present report is to quantify surface deviations in two XLPE liners implanted during revision THA and retrieved between four to five years after implantation. The two XLPE acetabular liners (Reflection, Smith and Nephew Inc., Memphis, TN) were retrieved from patients undergoing their second revision surgery, at 4.90 and 4.07 years. The retrieved liners and a new, non-implanted, unworn liner of the same size were scanned using micro-computed tomography (micro-CT). Articular surface deviation maps were created by comparing the retrievals to the unworn liner, based on the liner geometry obtained from micro-CT. The linear penetration rates were found to be 0.018 and 0.008 mm/year. Localized scratches and pits with deviations greater than 0.205 mm were also found on the articular surfaces of both liners. The XLPE liners retrieved from the two cases demonstrated low linear penetration rates. Regions with greater focal deviations were also apparent, likely due to third-body wear. The results are consistent with previously published clinical follow-ups of other XLPE liners.
Park, Myung-Sik; Yoon, Sun-Jung; Lee, Ju Rang
Cementation of a polyethylene liner into the well-fixed shell is a convenient option for revision total hip arthroplasty. We retrospectively reviewed 45 patients who had liner cementation to investigate the risk factors which gave rise to major complications and reoperation. Patients were observed for a minimum of 7 years (range 7.8-14 years). Relevant risk factors (age, BMI, surgical approach, previous cup size and position, types of coated surface) were assessed with Cox regression analysis. The mean Harris Hip Score was improved from 62.5 (range 57-68) preoperatively to 87.1 (range 70-97). A total of 7 hips (15.5%) had acetabular component loosening that was treated with reoperation. Prevalence of acetabular component loosening was statistically significantly higher in hydroxyapatite-coated group (5 of 13) than in the Ti-coated group (2 of 32, p = 0.015). All recurrent dislocations occurred in patients treated with a posterior approach. Diameter of the previous metal shell of below 54 mm showed a lower 10-year survival rate than those greater than 54 mm in diameter. PE liner cementation in stable metal cup is a useful alternative option for carefully selected patients. Pre-existing HA-coated cups as well as small sized cups were indicative of poor outcomes.
Ferreira, Susana; Karali, Berna
This paper examines how major earthquakes affected the returns and volatility of aggregate stock market indices in thirty-five financial markets over the last twenty years. Results show that global financial markets are resilient to shocks caused by earthquakes even if these are domestic. Our analysis reveals that, in a few instances, some macroeconomic variables and earthquake characteristics (gross domestic product per capita, trade openness, bilateral trade flows, earthquake magnitude, a tsunami indicator, distance to the epicenter, and number of fatalities) mediate the impact of earthquakes on stock market returns, resulting in a zero net effect. However, the influence of these variables is market-specific, indicating no systematic pattern across global capital markets. Results also demonstrate that stock market volatility is unaffected by earthquakes, except for Japan.
This paper examines how major earthquakes affected the returns and volatility of aggregate stock market indices in thirty-five financial markets over the last twenty years. Results show that global financial markets are resilient to shocks caused by earthquakes even if these are domestic. Our analysis reveals that, in a few instances, some macroeconomic variables and earthquake characteristics (gross domestic product per capita, trade openness, bilateral trade flows, earthquake magnitude, a tsunami indicator, distance to the epicenter, and number of fatalities) mediate the impact of earthquakes on stock market returns, resulting in a zero net effect. However, the influence of these variables is market-specific, indicating no systematic pattern across global capital markets. Results also demonstrate that stock market volatility is unaffected by earthquakes, except for Japan. PMID:26197482
Cowin, S C
Poroelasticity is a well-developed theory for the interaction of fluid and solid phases of a fluid-saturated porous medium. It is widely used in geomechanics and has been applied to bone by many authors in the last 30 years. The purpose of this work is, first, to review the literature related to the application of poroelasticity to the interstitial bone fluid and, second, to describe the specific physical and modeling considerations that establish poroelasticity as an effective and useful model for deformation-driven bone fluid movement in bone tissue. The application of poroelasticity to bone differs from its application to soft tissues in two important ways. First, the deformations of bone are small while those of soft tissues are generally large. Second, the bulk modulus of the mineralized bone matrix is about six times stiffer than that of the fluid in the pores while the bulk moduli of the soft tissue matrix and the pore water are almost the same. Poroelasticity and electrokinetics can be used to explain strain-generated potentials in wet bone. It is noted that strain-generated potentials can be used as an effective tool in the experimental study of local bone fluid flow, and that the knowledge of this technique will contribute to the answers of a number of questions concerning bone mineralization, osteocyte nutrition and the bone mechanosensory system.
Hurd, Michael; van Rooij, Maarten; Winter, Joachim
Despite its importance for the analysis of life-cycle behavior and, in particular, retirement planning, stock ownership by private households is poorly understood. Among other approaches to investigate this puzzle, recent research has started to elicit private households’ expectations of stock market returns. This paper reports findings from a study that collected data over a two-year period both on households’ stock market expectations (subjective probabilities of gains or losses) and on whether they own stocks. We document substantial heterogeneity in financial market expectations. Expectations are correlated with stock ownership. Over the two years of our data, stock market prices increased, and expectations of future stock market price changes also increased, lending support to the view that expectations are influenced by recent stock gains or losses. PMID:23997423
Hurd, Michael; van Rooij, Maarten; Winter, Joachim
Despite its importance for the analysis of life-cycle behavior and, in particular, retirement planning, stock ownership by private households is poorly understood. Among other approaches to investigate this puzzle, recent research has started to elicit private households' expectations of stock market returns. This paper reports findings from a study that collected data over a two-year period both on households' stock market expectations (subjective probabilities of gains or losses) and on whether they own stocks. We document substantial heterogeneity in financial market expectations. Expectations are correlated with stock ownership. Over the two years of our data, stock market prices increased, and expectations of future stock market price changes also increased, lending support to the view that expectations are influenced by recent stock gains or losses.
Lu, Shu Quan; Ito, Takao; Zhang, Jianbo
From the point of view of no-arbitrage pricing, what matters is how much volatility the stock has, for volatility measures the amount of profit that can be made from shorting stocks and purchasing options. With the short-sales constraints or in the absence of options, however, high volatility is likely to mean arbitrage from stock market. As emerging stock markets for China, investors are increasingly concerned about volatilities of Chinese two stock markets. We estimate volatility's models for Chinese stock markets' indexes using Markov chain Monte Carlo (MCMC) method and GARCH. We find that estimated values of volatility parameters are very high for all data frequencies. It suggests that stock returns are extremely volatile even at long term intervals in Chinese markets. Furthermore, this result could be considered that there seems to be arbitrage opportunities in Chinese stock markets.
...; sei whale, Nova Scotia stock; minke whale Canadian east coast stock; sperm whale, North Atlantic stock... and PBR. The abundance estimate for sei whale, Nova Scotia stock, in the draft 2012 SAR (77 FR...
Korhonen, Rami K; Koistinen, Arto; Konttinen, Yrjö T; Santavirta, Seppo S; Lappalainen, Reijo
Background Contact pressure of UHMWPE acetabular cup has been shown to correlate with wear in total hip replacement (THR). The aim of the present study was to test the hypotheses that the cup geometry, abduction angle, thickness and clearance can modify the stresses in cemented polyethylene cups. Methods Acetabular cups with different geometries (Link®: IP and Lubinus eccentric) were tested cyclically in a simulator at 45° and 60° abduction angles. Finite element (FE) meshes were generated and two additional designs were reconstructed to test the effects of the cup clearance and thickness. Contact pressures at cup-head and cup-cement interfaces were calculated as a function of loading force at 45°, 60° and 80° abduction angles. Results At the cup-head interface, IP experienced lower contact pressures than the Lubinus eccentric at low loading forces. However, at higher loading forces, much higher contact pressures were produced on the surface of IP cup. An increase in the abduction angle increased contact pressure in the IP model, but this did not occur to any major extent with the Lubinus eccentric model. At the cup-cement interface, IP experienced lower contact pressures. Increased clearance between cup and head increased contact pressure both at cup-head and cup-cement interfaces, whereas a decreased thickness of polyethylene layer increased contact pressure only at the cup-cement interface. FE results were consistent with experimental tests and acetabular cup deformations. Conclusion FE analyses showed that geometrical design, thickness and abduction angle of the acetabular cup, as well as the clearance between the cup and head do change significantly the mechanical stresses experienced by a cemented UHMWPE acetabular cup. These factors should be taken into account in future development of THR prostheses. FE technique is a useful tool with which to address these issues. PMID:15904521
... 26 Internal Revenue 11 2010-04-01 2010-04-01 true Exchanges of stock or securities solely for stock or securities. 1.1081-3 Section 1.1081-3 Internal Revenue INTERNAL REVENUE SERVICE, DEPARTMENT OF... § 1.1081-3 Exchanges of stock or securities solely for stock or securities. The exchange, without...
... 26 Internal Revenue 11 2010-04-01 2010-04-01 true Stock for stock of the same corporation. 1.1036...) INCOME TAX (CONTINUED) INCOME TAXES Common Nontaxable Exchanges § 1.1036-1 Stock for stock of the same corporation. (a) Section 1036 permits the exchange, without the recognition of gain or loss, of common...
... 12 Banks and Banking 9 2012-01-01 2012-01-01 false Capital stock requirements; redemption of excess stock. 1266.11 Section 1266.11 Banks and Banking FEDERAL HOUSING FINANCE AGENCY FEDERAL HOME LOAN BANKS ADVANCES Advances to Members § 1266.11 Capital stock requirements; redemption of excess stock....
... 26 Internal Revenue 11 2013-04-01 2013-04-01 false Exchanges of stock or securities solely for stock or securities. 1.1081-3 Section 1.1081-3 Internal Revenue INTERNAL REVENUE SERVICE, DEPARTMENT OF....c. Orders § 1.1081-3 Exchanges of stock or securities solely for stock or securities. The...
... 12 Banks and Banking 9 2013-01-01 2013-01-01 false Capital stock requirements; redemption of excess stock. 1266.11 Section 1266.11 Banks and Banking FEDERAL HOUSING FINANCE AGENCY FEDERAL HOME LOAN BANKS ADVANCES Advances to Members § 1266.11 Capital stock requirements; redemption of excess stock....
... 26 Internal Revenue 11 2011-04-01 2011-04-01 false Exchanges of stock or securities solely for stock or securities. 1.1081-3 Section 1.1081-3 Internal Revenue INTERNAL REVENUE SERVICE, DEPARTMENT OF....c. Orders § 1.1081-3 Exchanges of stock or securities solely for stock or securities. The...
... 26 Internal Revenue 11 2014-04-01 2014-04-01 false Exchanges of stock or securities solely for stock or securities. 1.1081-3 Section 1.1081-3 Internal Revenue INTERNAL REVENUE SERVICE, DEPARTMENT OF....c. Orders § 1.1081-3 Exchanges of stock or securities solely for stock or securities. The...
... 26 Internal Revenue 11 2012-04-01 2012-04-01 false Exchanges of stock or securities solely for stock or securities. 1.1081-3 Section 1.1081-3 Internal Revenue INTERNAL REVENUE SERVICE, DEPARTMENT OF....c. Orders § 1.1081-3 Exchanges of stock or securities solely for stock or securities. The...
... 12 Banks and Banking 10 2014-01-01 2014-01-01 false Capital stock requirements; redemption of excess stock. 1266.11 Section 1266.11 Banks and Banking FEDERAL HOUSING FINANCE AGENCY FEDERAL HOME LOAN BANKS ADVANCES Advances to Members § 1266.11 Capital stock requirements; redemption of excess stock....
... 12 Banks and Banking 7 2011-01-01 2011-01-01 false Capital stock requirements; unilateral redemption of excess stock. 950.11 Section 950.11 Banks and Banking FEDERAL HOUSING FINANCE BOARD FEDERAL... Housing Associates § 950.11 Capital stock requirements; unilateral redemption of excess stock. (a)...
... 25 Indians 1 2011-04-01 2011-04-01 false Stock grazing. 173.6 Section 173.6 Indians BUREAU OF... WITHDRAWN OR ACQUIRED IN CONNECTION WITH INDIAN IRRIGATION PROJECTS § 173.6 Stock grazing. Permittees may graze upon lands covered by such permits, such stock as may be required in connection with the...
... 25 Indians 1 2010-04-01 2010-04-01 false Stock grazing. 173.6 Section 173.6 Indians BUREAU OF... WITHDRAWN OR ACQUIRED IN CONNECTION WITH INDIAN IRRIGATION PROJECTS § 173.6 Stock grazing. Permittees may graze upon lands covered by such permits, such stock as may be required in connection with the...
... 47 Telecommunication 2 2011-10-01 2011-10-01 false Treasury stock. 32.4530 Section 32.4530... FOR TELECOMMUNICATIONS COMPANIES Instructions for Balance Sheet Accounts § 32.4530 Treasury stock. This account shall include the cost of the company's own capital stock which has been issued...
... 47 Telecommunication 2 2010-10-01 2010-10-01 false Capital stock. 32.4510 Section 32.4510... FOR TELECOMMUNICATIONS COMPANIES Instructions for Balance Sheet Accounts § 32.4510 Capital stock. (a) This account shall include the par value, stated amount, or in the case of no-par stock, the...
... 47 Telecommunication 2 2011-10-01 2011-10-01 false Capital stock. 32.4510 Section 32.4510... FOR TELECOMMUNICATIONS COMPANIES Instructions for Balance Sheet Accounts § 32.4510 Capital stock. (a) This account shall include the par value, stated amount, or in the case of no-par stock, the...
... 47 Telecommunication 2 2013-10-01 2013-10-01 false Capital stock. 32.4510 Section 32.4510... FOR TELECOMMUNICATIONS COMPANIES Instructions for Balance Sheet Accounts § 32.4510 Capital stock. (a) This account shall include the par value, stated amount, or in the case of no-par stock, the...
... 47 Telecommunication 2 2010-10-01 2010-10-01 false Treasury stock. 32.4530 Section 32.4530... FOR TELECOMMUNICATIONS COMPANIES Instructions for Balance Sheet Accounts § 32.4530 Treasury stock. This account shall include the cost of the company's own capital stock which has been issued...
... 47 Telecommunication 2 2013-10-01 2013-10-01 false Treasury stock. 32.4530 Section 32.4530... FOR TELECOMMUNICATIONS COMPANIES Instructions for Balance Sheet Accounts § 32.4530 Treasury stock. This account shall include the cost of the company's own capital stock which has been issued...
... 25 Indians 1 2012-04-01 2011-04-01 true Stock grazing. 173.6 Section 173.6 Indians BUREAU OF... WITHDRAWN OR ACQUIRED IN CONNECTION WITH INDIAN IRRIGATION PROJECTS § 173.6 Stock grazing. Permittees may graze upon lands covered by such permits, such stock as may be required in connection with the...
... 25 Indians 1 2013-04-01 2013-04-01 false Stock grazing. 173.6 Section 173.6 Indians BUREAU OF... WITHDRAWN OR ACQUIRED IN CONNECTION WITH INDIAN IRRIGATION PROJECTS § 173.6 Stock grazing. Permittees may graze upon lands covered by such permits, such stock as may be required in connection with the...
... 47 Telecommunication 2 2014-10-01 2014-10-01 false Capital stock. 32.4510 Section 32.4510... FOR TELECOMMUNICATIONS COMPANIES Instructions for Balance Sheet Accounts § 32.4510 Capital stock. (a) This account shall include the par value, stated amount, or in the case of no-par stock, the...
... 47 Telecommunication 2 2012-10-01 2012-10-01 false Capital stock. 32.4510 Section 32.4510... FOR TELECOMMUNICATIONS COMPANIES Instructions for Balance Sheet Accounts § 32.4510 Capital stock. (a) This account shall include the par value, stated amount, or in the case of no-par stock, the...
... 47 Telecommunication 2 2014-10-01 2014-10-01 false Treasury stock. 32.4530 Section 32.4530... FOR TELECOMMUNICATIONS COMPANIES Instructions for Balance Sheet Accounts § 32.4530 Treasury stock. This account shall include the cost of the company's own capital stock which has been issued...
... 47 Telecommunication 2 2012-10-01 2012-10-01 false Treasury stock. 32.4530 Section 32.4530... FOR TELECOMMUNICATIONS COMPANIES Instructions for Balance Sheet Accounts § 32.4530 Treasury stock. This account shall include the cost of the company's own capital stock which has been issued...
... 25 Indians 1 2014-04-01 2014-04-01 false Stock grazing. 173.6 Section 173.6 Indians BUREAU OF... WITHDRAWN OR ACQUIRED IN CONNECTION WITH INDIAN IRRIGATION PROJECTS § 173.6 Stock grazing. Permittees may graze upon lands covered by such permits, such stock as may be required in connection with the...
... 12 Banks and Banking 6 2010-01-01 2010-01-01 false Capital stock. 725.5 Section 725.5 Banks and Banking NATIONAL CREDIT UNION ADMINISTRATION REGULATIONS AFFECTING CREDIT UNIONS NATIONAL CREDIT UNION ADMINISTRATION CENTRAL LIQUIDITY FACILITY § 725.5 Capital stock. (a) The capital stock of the Facility is...
Lopus, Jane; Placone, Dennis
Identifies a Web site providing information about stock market simulations for high school economics courses. Divides the information into two tables: (1) the structure of online stock market games; and (2) the determination of portfolio values of online stock market games. States that changes and updates are available at Web sites. (JEH)
Parker, George O.
How one teacher motivated students to learn about the stock market by allowing them to actually invest money. Class discussion covered inexpensive ways to buy stock, choosing securities, and buying and selling stock. Suggestions are offered for adapting this project for use at the secondary level. (TA)
... 27 Alcohol, Tobacco Products and Firearms 1 2011-04-01 2011-04-01 false Vinegar stock. 24.217... OF THE TREASURY LIQUORS WINE Production of Other Than Standard Wine § 24.217 Vinegar stock. Vinegar... commercial standards for the production of vinegar. Vinegar stock may be made only by the addition of...
... 27 Alcohol, Tobacco Products and Firearms 1 2014-04-01 2014-04-01 false Vinegar stock. 24.217... OF THE TREASURY ALCOHOL WINE Production of Other Than Standard Wine § 24.217 Vinegar stock. Vinegar... commercial standards for the production of vinegar. Vinegar stock may be made only by the addition of...
... 27 Alcohol, Tobacco Products and Firearms 1 2010-04-01 2010-04-01 false Vinegar stock. 24.217... OF THE TREASURY LIQUORS WINE Production of Other Than Standard Wine § 24.217 Vinegar stock. Vinegar... commercial standards for the production of vinegar. Vinegar stock may be made only by the addition of...
... 27 Alcohol, Tobacco Products and Firearms 1 2013-04-01 2013-04-01 false Vinegar stock. 24.217... OF THE TREASURY ALCOHOL WINE Production of Other Than Standard Wine § 24.217 Vinegar stock. Vinegar... commercial standards for the production of vinegar. Vinegar stock may be made only by the addition of...
... 27 Alcohol, Tobacco Products and Firearms 1 2012-04-01 2012-04-01 false Vinegar stock. 24.217... OF THE TREASURY LIQUORS WINE Production of Other Than Standard Wine § 24.217 Vinegar stock. Vinegar... commercial standards for the production of vinegar. Vinegar stock may be made only by the addition of...
Uebelhart, Brigitte; Rizzoli, René
Calcium intake shows a small impact on bone mineral density and fracture risk. Denosumab is a more potent inhibitor of bone resorption than zoledronate. Abaloparatide, PTHrP analog, increases bone mineral density and decreases fracture incidence. Teriparatide could be delivered via a transdermic device. Romosozumab and odanacatib improve calculated bone strength. Sequential or combined treatments with denosumab and teriparatide could be of interest, but not denosumab followed by teriparatide. Fibrous dysplasia, Paget disease and hypophosphatasia are updated, as well as atypical femoral fracture and osteonecrosis of the jaw.
Giraud, J Y; Villemin, S; Darmana, R; Cahuzac, J P; Autefage, A; Morucci, J P
Bone cutting has always been a problem for surgeons because bone is a hard living material, and many osteotomes are still very crude tools. Technical improvement of these surgical tools has first been their motorization. Studies of the bone cutting process have indicated better features for conventional tools. Several non-conventional osteotomes, particularly ultrasonic osteotomes are described. Some studies on the possible use of lasers for bone cutting are also reported. Use of a pressurised water jet is also briefly examined. Despite their advantages, non-conventional tools still require improvement if they are to be used by surgeons.
Meena, Sanjay; Sharma, Pankaj Kumar; Mittal, Samarth; Sharma, Jyoti; Chowdhury, Buddhadev
Introduction: Modified Stoppa approach was introduced as an alternative to ilioinguinal approach for management of anterior fractures of acetabulum in order to reduce complications of the latter. However, the efficacy of either approach over other is not well established. The aim of this meta-analysis is to compare the efficacy of modified stoppa and ilioinguinal approach in the management of acetabular fractures in terms of a) quality of reduction achieved b) complication rates c) functional outcomes d) operative time e) intra-operative blood loss. Methods: Databases of PubMed, EMBASE and Cochrane registry of controlled trials were taken into consideration for studies on modified Stoppa approach versus Ilioinguinal approach group for the treatment of anterior acetabular fractures. Dichotomous variables were presented as risk ratios (RRs) /Odds Ratio (OR) with 95% confidence intervals (CIs), and continuous data was measured as mean differences, with 95% CIs. Result: Four studies involving 375 patients were included in this meta-analysis. Out of those 375 patients, 192 were managed with ilioinguinal approach and 183 were managed with modified Stoppa approach. Anatomical reduction was significantly higher in Stoppa group (p=0.052, RR=1. 19 (1.02, 1.37), p=0. 90, I2=0%). The complication rate was significantly higher in the Ilioinguinal approach as compared with the Stoppa approach (p=0.01, RR 0.63 (0.44 to 0.91), p=0.73 (I2= 0%). The operative time was significantly shorter with modified Stoppa approach (MD = -48.79 (-80.29 to -17.30), p=0.002). No significant differences were found between the two groups in terms of their functional outcomes (p=0.63, RR 0.96 (-0.80 to 1.15), p=0. 56, I2=0%) and blood loss (MD= -212.89 (-476.27 to 50.49) p=0. 06, I2=71%). Conclusion: Anterior acetabular fractures, if operated with the modified Stoppa approach were found to have better reduction and lower complication rates with less operative time, when compared to ilioinguinal
Davranov, K D; Guliamova, K A; Alimova, B Kh; Turapova, N M
Enzymatic hydrolysis of neutral fat of cotton oil soap stock with a nonspecific lipase produced by Oospora lactis F-500 was designed. The culture liquid and a preparation of enzyme obtained by precipitation with isopropanol from a filtrate of the culture liquid were used. Utilization of cotton oil soap stock as the only source of carbon during cultivation of the fungus was studied. The rate of hydrolysis of soap stock fat strongly depended on the way of biological conversion of cotton oil soap stock. The most effective utilization was observed during cultivation of the fungus in the medium containing soap stock.
Choi, James J.; Jin, Li; Yan, Hongjun
Using holdings data on a representative sample of all Shanghai Stock Exchange investors, we show that increases in ownership breadth (the fraction of market participants who own a stock) predict low returns: highest change quintile stocks underperform lowest quintile stocks by 23% per year. Small retail investors drive this result. Retail ownership breadth increases appear to be correlated with overpricing. Among institutional investors, however, the opposite holds: Stocks in the top decile of wealth-weighted institutional breadth change outperform the bottom decile by 8% per year, consistent with prior work that interprets breadth as a measure of short-sales constraints. PMID:24764801
... stock or fractional shares of my stock or obligations or the stock or obligations of my affiliates? 150... obligations or the stock or obligations of my affiliates? If the retention of investments in your stock or obligations or the stock or obligations of an affiliate in fiduciary accounts is consistent with...
Siokis, Fotios M.
This paper presents a brief analysis on the distribution of magnitude of major stock market shocks. Based on the Gutenberg-Richter law in geophysics, we model the dynamics of market index returns prior and after major crashes in search of statistical regularities. For a large number of market crashes, our analysis suggests that the distribution of market volatility before and after the stock market crash is described well by the Gutenberg-Richter law, which reflects the scale-invariance and self-similarity of the underlying dynamics by a robust power-law relation. In addition, the rate of the decay of the aftershock sequence is well described by another power law, which is known as the Omori law. Power law relaxation seems to be a common behavior observed in complex systems such as the financial markets.
Mediouni, Mohamed; Schlatterer, Daniel R; Khoury, Amal; Von Bergen, Tobias; Shetty, Sunil H; Arora, Manit; Dhond, Amit; Vaughan, Neil; Volosnikov, Alexander
The drilling bone may potentially cause excessive frictional heat, which can lead to local bone necrosis. This heat generation and local necrosis has been suggested to contribute to the resorption of bone around the placed screws, ending in loss of screw purchase in the bone and inadvertent loosening and/or the bone-implant construct. In vivo studies on this subject have inherent obstacles not the least of which is controlling the variables and real time bone temperature data acquisition. Theoretical models can be generated using computer software and the inclusion of known constants for the mechanical properties of metal and bone. These known Data points for the variables (drill bit and bone) enables finite element analysis of various bone drilling scenarios. An elastic-plastic three-dimensional (3D) acetabular bone mode was developed and finite element model analysis (FEA) was applied to various simulated drilling procedures. The FEA results clearly indicate that the depth of drilling and the drill speed both have a significant effect on the temperature during drilling procedures. The reduction of the feeding speed leads to a reduction in bone temperature. Our data suggests that reducing the feeding speed regardless of RPMs and pressure applied could be a simple useful and effective way to reduce drilling temperatures. This study is the first step in helping any surgeon who drills bone and places screws to better understand the ideal pressure to apply and drill speed to employ and advance rate to avoid osteonecrosis. © 2017 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res.
... shoulder blade or scapula (say: SKA-pyuh-luh), a large triangular bone on the upper back corner of each side of the ribcage. The arm is made up of three bones: the humerus (say: HYOO-muh-rus), which is above your elbow, and the radius (say: RAY-dee-us) and ulna (say: UL- ...
Johnson, Jaclyn; Kassing, Sharon
Describes cooperation with the Saint Louis Zoo to provide opportunities for elementary school students to learn about bones, how animals move, what they eat, and how much they grow. Uses biofacts which include bones, skulls, and other parts to make the laboratory a hands-on experience for students. (YDS)
Gu, Yanqing; Wang, Qing; Cui, Weiding; Fan, Weimin
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
Lim, Jason BT; Ang, Chia Liang; Pang, Hee Nee
Introduction: Bipolar hemi-arthroplasty of the hip is a commonly performed procedure in elderly patients with intra-capsular fracture of the neck of the femur with good short-term results for pain relief, return to activity and morbidity. The incidence of intra-pelvic prosthesis migration or protrusion is rare and one of the inciting factors is chronic low-grade sepsis. Acetabular prosthesis protrusion poses a difficult and challenging surgical problem due to surrounding neurovascular structures. Case Presentation: We present a case report of 60-year-old Chinese female suffering from chronic sepsis of the hip joint causing acetabular prosthetic protrusion with a concomitant peri-prosthetic femoral shaft fracture secondary to a fall, 5 years post index surgery of bipolar hemiarthroplasty for an intra-capsular neck of femur fracture. This patient subsequently underwent a two-stage revision total hip arthroplasty. We aim to discuss the diagnostic approach and surgical management of this complex case of infected protruded bipolar hip hemi-arthroplasty. Conclusion: We highlight three recommendations from this clinical experience. Firstly, there should be a high index of suspicion for chronic infection in protruded prostheses following low energy trauma. Secondly, pre-operative planning for infected protruded prosthetic hips is essential, including arteriogram and a two-staged procedure to tackle possible soft tissue complications. Thirdly, the combined use of serological markers, fluid aspiration as well as intra-operative frozen section is important in the management of PJI and to confirm bacterial eradication before re-implantation. PMID:28116262
Kurosaka, Kenji; Fukunishi, Shigeo; Fukui, Tomokazu; Nishio, Shoji; Fujihara, Yuki; Okahisa, Shohei; Takeda, Yu; Daimon, Takashi; Yoshiya, Shinichi
Implant positioning is one of the critical factors that influences postoperative outcome of total hip arthroplasty (THA). Malpositioning of the implant may lead to an increased risk of postoperative complications such as prosthetic impingement, dislocation, restricted range of motion, polyethylene wear, and loosening. In 2012, the intraoperative use of smartphone technology in THA for improved accuracy of acetabular cup placement was reported. The purpose of this study was to examine the accuracy of an iPhone/iPad-guided technique in positioning the acetabular cup in THA compared with the reference values obtained from the image-free navigation system in a cadaveric experiment. Five hips of 5 embalmed whole-body cadavers were used in the study. Seven orthopedic surgeons (4 residents and 3 senior hip surgeons) participated in the study. All of the surgeons examined each of the 5 hips 3 times. The target angle was 38°/19° for operative inclination/anteversion angles, which corresponded to radiographic inclination/anteversion angles of 40°/15°. The simultaneous assessment using the navigation system showed mean±SD radiographic alignment angles of 39.4°±2.6° and 16.4°±2.6° for inclination and anteversion, respectively. Assessment of cup positioning based on Lewinnek's safe zone criteria showed all of the procedures (n=105) achieved acceptable alignment within the safe zone. A comparison of the performances by resident and senior hip surgeons showed no significant difference between the groups (P=.74 for inclination and P=.81 for anteversion). The iPhone/iPad technique examined in this study could achieve acceptable performance in determining cup alignment in THA regardless of the surgeon's expertise. [Orthopedics. 2016; 39(4):e621-e626.].
Bonanno; Vandewalle; Mantegna
We investigate sets of financial nonredundant and nonsynchronously recorded time series. The sets are composed by a number of stock market indices located all over the world in five continents. By properly selecting the time horizon of returns and by using a reference currency we find a meaningful taxonomy. The detection of such a taxonomy proves that interpretable information can be stored in a set of nonsynchronously recorded time series.
Onnela, Jukka-Pekka; Töyli, Juuso; Kaski, Kimmo
Tick size is an important aspect of the micro-structural level organization of financial markets. It is the smallest institutionally allowed price increment, has a direct bearing on the bid-ask spread, influences the strategy of trading order placement in electronic markets, affects the price formation mechanism, and appears to be related to the long-term memory of volatility clustering. In this paper we investigate the impact of tick size on stock returns. We start with a simple simulation to demonstrate how continuous returns become distorted after confining the price to a discrete grid governed by the tick size. We then move on to a novel experimental set-up that combines decimalization pilot programs and cross-listed stocks in New York and Toronto. This allows us to observe a set of stocks traded simultaneously under two different ticks while holding all security-specific characteristics fixed. We then study the normality of the return distributions and carry out fits to the chosen distribution models. Our empirical findings are somewhat mixed and in some cases appear to challenge the simulation results.
Laio, Francesco; Ridolfi, Luca; D'Odorico, Paolo
Human societies rely on food reserves and the importation of agricultural goods as means to cope with crop failures and associated food shortage. While food trade has been the subject of intensive investigations in recent years, food reserves remain poorly quantified. It is unclear how food stocks are changing and whether they are declining. In this study we use food stock records for 92 products to reconstruct 50 years of aggregated food reserves, expressed in caloric equivalent (kcal), at the regional and global scales. A detailed statistical analysis demonstrates that the overall regional and global per-capita food stocks are stationary, challenging a widespread impression that food reserves are shrinking. We develop a statistically-sound stochastic representation of stock dynamics and take the stock-halving probability as a measure of the natural variability of the process. We find that there is a 20% probability that the global per-capita stocks will be halved by 2050. There are, however, some strong regional differences: Western Europe and the region encompassing North Africa and the Middle East have smaller halving probabilities and smaller per-capita stocks, while North America and Oceania have greater halving probabilities and greater per-capita stocks than the global average. Africa exhibits low per-capita stocks and relatively high probability of stock halving by 2050, which reflects a state of higher food insecurity in this continent.
Chun, Kwang J
Conventional radiographic methods allow physicians to visualize bone structure. However, they do not offer information on the bone mineral density (BMD), which can facilitate early diagnosis and treatment of osteoporosis. Bone densitometry, by contrast, helps to detect bone mineral loss at an early stage because it provides accurate quantitative measurement of BMD. With an emphasis on quantification, shorter scanning time and precision, scientists have been developing BMD measurement devices that use absorption technique. They first developed single-energy absorptiometry (single-photon absorptiometry) by using I-125, which could measure BMD of peripheral bones. Single-photon absorptiometry was replaced by dual-energy absorptiometry (dual photon absorptiometry [DPA]) that used gadolinium-153. DPA had greater accuracy in measuring the BMD of central skeletal bones. Single-energy x-ray absorptiometry was also developed but it had limitations in measuring central skeletal BMD. In the mid-1980s, dual-energy x-ray absorptiometry (DXA) was introduced and widely accepted for the early detection, treatment, and follow-up study of osteoporosis. There are several reasons for the popularity. DXA can measure BMD of posteroanterior spine and hip in a much shorter time than DPA while being capable of measuring BMD of peripheral bones. Other advantages include very low radiation doses to the patients, high image resolution, precision, and stable calibration of the instruments. In recent years, DXA has also been applied to lateral spine for the density of trabecular bone, to the whole body for the measurement of total body bone density and for the body composition, and to the spine for the vertebral fracture assessment. Still, posteroanterior spine and hip scans remain the most common applications of DXA because data on the normal range of BMD of the skeletal sites for different age, sex, and ethnic groups are compiled and made available with the devices, which gives the physician
Taddei, Paola; Affatato, Saverio; Fagnano, Concezio; Toni, Aldo
This study was aimed at comparing the oxidative degradation of commercial acetabular cups made of cross-linked polyethylene (XLPE) and conventional ultrahigh molecular weight polyethylene (UHMWPE). After testing against deliberately scratched CoCrMo femoral heads in a hip joint simulator, the cups, microtomed parallel to the articulating surface, were analyzed by IR spectroscopy. Due to the potential for artifacts caused by absorbed contaminants, the IR spectra were compared only after hexane extraction; actually, XLPE was found to absorb more serum than UHMWPE. The two sets of unworn acetabular cups showed different oxidation patterns with consequently different distributions of carbonyl species; unworn XLPE was characterized by lower contents of carbonyl species and hydrogen-bonded alcohols and higher contents of trans-vinylene species than unworn UHMWPE. Upon simulator testing, UHMWPE showed more significant changes in oxidation indexes and distribution of carbonyl compounds than XLPE, confirming a better wear behavior for XLPE under the adopted testing conditions.
Zietz, Carmen; Fabry, Christian; Baum, Felix; Bader, Rainer; Kluess, Daniel
The aim of the present wear simulator study was to assess the effect of steep acetabular cup positions on the wear propagation of highly cross-linked-PE (HX-PE) liners. Furthermore, a finite element analysis (FEA) was performed in order to calculate the stress within the HX-PE material in case of steep cup positions under physiological loadings. The higher stress in the HX-PE at a steep acetabular cup position did not result in increased wear in the present wear simulator study. The gravimetrical wear rates at normal (45°) and steep cup inclinations (75°) showed wear amounts of 3.15±0.27mg and 2.18±0.31mg per million cycles (p=0.028), respectively. However, FEA revealed clear increase in stress at the HX-PE liners with respect to steep cup positions.
Lim, Seung-Jae; Lee, Keun-Ho; Park, Shin-Hyung; Park, Youn-Soo
The present study was undertaken to document outcomes of cementation of a highly cross-linked polyethylene (PE) liner into a well-fixed acetabular metal shell in 36 hips. All operations were performed by a single surgeon using only one type of liner. Patients were followed for a mean of 6.1 years (range, 3-8 years). Mean Harris hip score improved from 58 points preoperatively to 91 points postoperatively. There were no cases of PE liner dislodgement or progressive osteolysis. 1 hip (2.8%) required revision surgery for acetabular cup loosening with greater trochanteric fracture. Complications included 1 peroneal nerve palsy and 1 dislocation. The results of this study and previous reports demonstrated that cementation of highly cross-linked PE liner into well-fixed metal shell could provide good midterm durability.
Tamam, Cüneyt; Howse, Elizabeth A.; Tamam, Muge; Barnes, Ryan H.; Kelsey, Thomas J.; Perry, Brad; Stubbs, Allston J.
Osteoid osteoma is a benign osteoblastic tumor that occurs in the subcortical shaft and metaphysis of the long bones of the lower extremities; however, intra-articular lesions are also possible. Intra-articular osteoid osteomas are rare, and clinical symptoms are often less specific and, thereby, may lead to misdiagnosis. The definitive treatment for osteoid osteoma is the excision of the nidus. We present the case of a 23-year-old man with a 4-year history of right anterior hip pain, subsequently diagnosed with a subarticular osteoid osteoma located in the right anterior acetabulum. Hip arthroscopic excision of the juxta-articular osteoid osteoma is presented as an effective treatment, with the advantage of less potential damage to normal bone and cartilage, as well as the additional benefits available with hip arthroscopy. PMID:26052484
Kim, Jun Hyun; Kim, Won Il; Kim, Ji Yeon; Choe, Won Joo
Peroneal nerve palsy can be caused by various etiology. We report unilateral peroneal nerve palsy after compression stockings application. A 64-year-old man underwent off-pump coronary bypass graft. Surgeon did not use saphenous vein for the bypass graft. Sedation was stopped after 3 h postoperative. After 16 h, for prophylaxis of deep vein thrombosis, knee-high elastic stocking was applied. After 1 h, he took off right stocking because of numbness but left stocking was kept. After 24 h postoperative, (8 h after stocking application) patient complained suddenly left foot drop. Manual muscle test revealed 0/5 of ankle dorsiflexion, ankle eversion, and toe extension. Sensory was decreased to 70% in lower half of anterolateral aspect of tibia, foot dorsum, and toes. Foot drop and sensory abnormality decreased in 3 weeks. Cardiac surgery patients already have many risk factors for peripheral neuropathy. Clinicians should be careful when applying stockings on those patients. PMID:27833497
Kim, Jun Hyun; Kim, Won Il; Kim, Ji Yeon; Choe, Won Joo
Peroneal nerve palsy can be caused by various etiology. We report unilateral peroneal nerve palsy after compression stockings application. A 64-year-old man underwent off-pump coronary bypass graft. Surgeon did not use saphenous vein for the bypass graft. Sedation was stopped after 3 h postoperative. After 16 h, for prophylaxis of deep vein thrombosis, knee-high elastic stocking was applied. After 1 h, he took off right stocking because of numbness but left stocking was kept. After 24 h postoperative, (8 h after stocking application) patient complained suddenly left foot drop. Manual muscle test revealed 0/5 of ankle dorsiflexion, ankle eversion, and toe extension. Sensory was decreased to 70% in lower half of anterolateral aspect of tibia, foot dorsum, and toes. Foot drop and sensory abnormality decreased in 3 weeks. Cardiac surgery patients already have many risk factors for peripheral neuropathy. Clinicians should be careful when applying stockings on those patients.
Weymouth, Patricia P.
Describes an activity which introduces students to the nature and challenges of paleoanthropology. In the exercise, students identify diagrammed bones and make interpretations about the creature. Presents questions and tasks employed in the lesson. (ML)
Donangelo, Raul; Jensen, Mogens H.; Simonsen, Ingve; Sneppen, Kim
The waiting time needed for a stock market index to undergo a given percentage change in its value is found to have an up down asymmetry, which, surprisingly, is not observed for the individual stocks composing that index. To explain this, we introduce a market model consisting of randomly fluctuating stocks that occasionally synchronize their short term draw-downs. These synchronous events are parametrized by a 'fear factor', that reflects the occurrence of dramatic external events which affect the financial market.
Del Fattore, Andrea; Capannolo, Marta; Rucci, Nadia
Interplays between bone and bone marrow are not limited to merely anatomic and histological connections, but include a tight functional correlation. Bone marrow resides within the medullary cavity of the bones and the process of hematopoiesis is regulated, at least in part, by bone cells. Moreover, osteoclasts and osteoblasts derive from precursors of hematopoietic and mesenchymal origin, respectively, both residing within the bone marrow. Alterations in one of these components typically cause impairment in the other, so diseases of the bone marrow compartment often affect the bone and vice versa. All these findings could make us to speculate that bone and bone marrow are not two separate districts, but can be considered as the two elements of the same unique functional unit, the bone-bone marrow organ. Here we will describe histological and functional interplays between bone and bone marrow, and will illustrate some diseases in which this tight correlation is evident.
Scholes, S C; Inman, I A; Unsworth, A; Jones, E
New material combinations have been introduced as the bearing surfaces of hip prostheses in an attempt to prolong their life by overcoming the problems of failure due to wear-particle-induced osteolysis. This will hopefully reduce the need for revision surgery. The study detailed here used a hip simulator to assess the volumetric wear rates of large-diameter carbon-fibre-reinforced pitch-based poly(ether-ether-ketone) (CFR-PEEK) acetabular cups articulating against alumina femoral heads. The joints were tested for 25 x 10(6) cycles. Friction tests were also performed on these joints to determine the lubrication regime under which they operate. The average volumetric wear rate of the CFR-PEEK acetabular component of 54 mm diameter was 1.16 mm(3)/10(6) cycles, compared with 38.6 mm(3)/10(6) cycles for an ultra-high-molecular-weight polyethylene acetabular component of 28 mm diameter worn against a ceramic head. This extremely low wear rate was sustained over 25 x 10(6) cycles (the equivalent of up to approximately 25 years in vivo). The frictional studies showed that the joints worked under the mixed-boundary lubrication regime. The low wear produced by these joints showed that this novel joint couple offers low wear rates and therefore may be an alternative material choice for the reduction of osteolysis.
Cabrera Serrenho, André; Allwood, Julian M
Recent literature on material flow analysis has been focused on quantitative characterization of past material flows. Fewer analyses exist on past and prospective quantification of stocks of materials in-use. Some of these analyses explore the composition of products' stocks, but a focus on the characterization of material stocks and its relation with service delivery is often neglected. We propose the use of the methods of human demography to characterize material stocks, defined herein as stock demographics, exploring the insights that this approach could provide for the sustainable management of materials. We exemplify an application of stock demographics by characterizing the composition and service delivery of iron, steel, and aluminum stocks of cars in Great Britain, 2002-2012. The results show that in this period the stock has become heavier, it is traveling less, and it is idle for more time. The visualization of material stocks' dynamics demonstrates the pace of product replacement as a function of its usefulness and enables the formulation of policy interventions and the exploration of future trends.
... 41 Public Contracts and Property Management 3 2013-07-01 2013-07-01 false Stock control. 109-27... control. (a) Stock control shall be maintained on the basis of stock record accounts of inventories on... property under stock control for greater than 90 days shall be maintained in stock record accounts....
... 41 Public Contracts and Property Management 3 2011-01-01 2011-01-01 false Stock control. 109-27... control. (a) Stock control shall be maintained on the basis of stock record accounts of inventories on... property under stock control for greater than 90 days shall be maintained in stock record accounts....
... 41 Public Contracts and Property Management 3 2012-01-01 2012-01-01 false Stock control. 109-27... control. (a) Stock control shall be maintained on the basis of stock record accounts of inventories on... property under stock control for greater than 90 days shall be maintained in stock record accounts....
... 26 Internal Revenue 5 2012-04-01 2011-04-01 true Incentive stock options defined. 1.422-2 Section... (CONTINUED) INCOME TAXES (CONTINUED) Certain Stock Options § 1.422-2 Incentive stock options defined. (a) Incentive stock option defined—(1) In general. The term incentive stock option means an option that...
... 12 Banks and Banking 10 2014-01-01 2014-01-01 false Issuance and form of stock. 1263.21 Section... Stock Requirements § 1263.21 Issuance and form of stock. (a) A Bank shall issue to each new member, as of the effective date of membership, stock in the member's name for the amount of stock purchased...
... 12 Banks and Banking 9 2012-01-01 2012-01-01 false Issuance and form of stock. 1263.21 Section... Stock Requirements § 1263.21 Issuance and form of stock. (a) A Bank shall issue to each new member, as of the effective date of membership, stock in the member's name for the amount of stock purchased...
... 26 Internal Revenue 5 2014-04-01 2014-04-01 false Incentive stock options defined. 1.422-2 Section... (CONTINUED) INCOME TAXES (CONTINUED) Certain Stock Options § 1.422-2 Incentive stock options defined. (a) Incentive stock option defined—(1) In general. The term incentive stock option means an option that...
... 12 Banks and Banking 7 2011-01-01 2011-01-01 false Issuance and form of stock. 1263.21 Section... Stock Requirements § 1263.21 Issuance and form of stock. (a) A Bank shall issue to each new member, as of the effective date of membership, stock in the member's name for the amount of stock purchased...
... 26 Internal Revenue 5 2011-04-01 2011-04-01 false Incentive stock options defined. 1.422-2 Section... (CONTINUED) INCOME TAXES (CONTINUED) Certain Stock Options § 1.422-2 Incentive stock options defined. (a) Incentive stock option defined—(1) In general. The term incentive stock option means an option that...
... 12 Banks and Banking 8 2014-01-01 2014-01-01 false Classes of capital stock. 931.1 Section 931.1... STANDARDS FEDERAL HOME LOAN BANK CAPITAL STOCK § 931.1 Classes of capital stock. The authorized capital stock of a Bank shall consist of the following instruments: (a) Class A stock, which shall: (1) Have...
... 12 Banks and Banking 7 2011-01-01 2011-01-01 false Classes of capital stock. 931.1 Section 931.1... STANDARDS FEDERAL HOME LOAN BANK CAPITAL STOCK § 931.1 Classes of capital stock. The authorized capital stock of a Bank shall consist of the following instruments: (a) Class A stock, which shall: (1) Have...
... 26 Internal Revenue 5 2013-04-01 2013-04-01 false Incentive stock options defined. 1.422-2 Section... (CONTINUED) INCOME TAXES (CONTINUED) Certain Stock Options § 1.422-2 Incentive stock options defined. (a) Incentive stock option defined—(1) In general. The term incentive stock option means an option that...
... 12 Banks and Banking 8 2012-01-01 2012-01-01 false Classes of capital stock. 931.1 Section 931.1... STANDARDS FEDERAL HOME LOAN BANK CAPITAL STOCK § 931.1 Classes of capital stock. The authorized capital stock of a Bank shall consist of the following instruments: (a) Class A stock, which shall: (1) Have...
... 12 Banks and Banking 9 2013-01-01 2013-01-01 false Issuance and form of stock. 1263.21 Section... Stock Requirements § 1263.21 Issuance and form of stock. (a) A Bank shall issue to each new member, as of the effective date of membership, stock in the member's name for the amount of stock purchased...
... 12 Banks and Banking 8 2013-01-01 2013-01-01 false Classes of capital stock. 931.1 Section 931.1... STANDARDS FEDERAL HOME LOAN BANK CAPITAL STOCK § 931.1 Classes of capital stock. The authorized capital stock of a Bank shall consist of the following instruments: (a) Class A stock, which shall: (1) Have...
... 41 Public Contracts and Property Management 3 2010-07-01 2010-07-01 false Stock control. 109-27... control. (a) Stock control shall be maintained on the basis of stock record accounts of inventories on... property under stock control for greater than 90 days shall be maintained in stock record accounts....
... 12 Banks and Banking 6 2014-01-01 2012-01-01 true Conversion from stock form depository institution to Federal stock association. 552.2-6 Section 552.2-6 Banks and Banking OFFICE OF THRIFT SUPERVISION, DEPARTMENT OF THE TREASURY FEDERAL STOCK ASSOCIATIONS-INCORPORATION, ORGANIZATION, AND...
... Revenue Service 26 CFR Part 1 RIN 1545-BJ74 Indirect Stock Transfers and Coordination Rule Exceptions; Transfers of Stock or Securities in Outbound Asset Reorganizations AGENCY: Internal Revenue Service (IRS... between asset transfers and indirect stock transfers for certain outbound asset reorganizations....
... 12 Banks and Banking 6 2013-01-01 2012-01-01 true Conversion from stock form depository institution to Federal stock association. 552.2-6 Section 552.2-6 Banks and Banking OFFICE OF THRIFT SUPERVISION, DEPARTMENT OF THE TREASURY FEDERAL STOCK ASSOCIATIONS-INCORPORATION, ORGANIZATION, AND...
... 12 Banks and Banking 5 2010-01-01 2010-01-01 false Conversion from stock form depository institution to Federal stock association. 552.2-6 Section 552.2-6 Banks and Banking OFFICE OF THRIFT SUPERVISION, DEPARTMENT OF THE TREASURY FEDERAL STOCK ASSOCIATIONS-INCORPORATION, ORGANIZATION, AND...
... 12 Banks and Banking 1 2013-01-01 2013-01-01 false Conversion from stock form depository institution to Federal stock association. 152.18 Section 152.18 Banks and Banking COMPTROLLER OF THE CURRENCY, DEPARTMENT OF THE TREASURY FEDERAL STOCK ASSOCIATIONS-INCORPORATION, ORGANIZATION, AND CONVERSION §...
... 12 Banks and Banking 5 2011-01-01 2011-01-01 false Conversion from stock form depository institution to Federal stock association. 552.2-6 Section 552.2-6 Banks and Banking OFFICE OF THRIFT SUPERVISION, DEPARTMENT OF THE TREASURY FEDERAL STOCK ASSOCIATIONS-INCORPORATION, ORGANIZATION, AND...
... 12 Banks and Banking 1 2012-01-01 2012-01-01 false Conversion from stock form depository institution to Federal stock association. 152.18 Section 152.18 Banks and Banking COMPTROLLER OF THE CURRENCY, DEPARTMENT OF THE TREASURY FEDERAL STOCK ASSOCIATIONS-INCORPORATION, ORGANIZATION, AND CONVERSION §...
... 12 Banks and Banking 6 2012-01-01 2012-01-01 false Conversion from stock form depository institution to Federal stock association. 552.2-6 Section 552.2-6 Banks and Banking OFFICE OF THRIFT SUPERVISION, DEPARTMENT OF THE TREASURY FEDERAL STOCK ASSOCIATIONS-INCORPORATION, ORGANIZATION, AND...
... 12 Banks and Banking 1 2014-01-01 2014-01-01 false Conversion from stock form depository institution to Federal stock association. 152.18 Section 152.18 Banks and Banking COMPTROLLER OF THE CURRENCY, DEPARTMENT OF THE TREASURY FEDERAL STOCK ASSOCIATIONS-INCORPORATION, ORGANIZATION, AND CONVERSION §...
This guide to a unit on a simulation game about the stock market contains an instructional text and two separate simulations. Through directed lessons and reproducible worksheets, the unit teaches students about business ownership, stock exchanges, benchmarks, commissions, why prices change, the logistics of buying and selling stocks, and how to…
... and display the bone density measurements on a computer monitor. top of page How is the procedure performed? ... passed over the area, generating images on a computer monitor. You must hold very still and may be ...
... financing of stock options and stock purchase rights qualified or restricted under Internal Revenue Code... provisions to financing of stock options and stock purchase rights qualified or restricted under Internal... intended to apply to the financing of stock options restricted or qualified under the Internal Revenue...
Vasilakopoulos, Paraskevas; Maravelias, Christos D; Tserpes, George
In recent years, fisheries management has succeeded in stabilizing and even improving the state of many global fisheries resources [1-5]. This is particularly evident in areas where stocks are exploited in compliance with scientific advice and strong institutional structures are in place [1, 5]. In Europe, the well-managed northeast (NE) Atlantic fish stocks have been recovering in response to decreasing fishing pressure over the past decade [3-6], albeit with a long way to go for a universal stock rebuild [3, 7]. Meanwhile, little is known about the temporal development of the European Mediterranean stocks, whose management relies on input controls that are often poorly enforced. Here, we perform a meta-analysis of 42 European Mediterranean stocks of nine species in 1990-2010, showing that exploitation rate has been steadily increasing, selectivity (proportional exploitation of juveniles) has been deteriorating, and stocks have been shrinking. We implement species-specific simulation models to quantify changes in exploitation rate and selectivity that would maximize long-term yields and halt stock depletion. We show that stocks would be more resilient to fishing and produce higher long-term yields if harvested a few years after maturation because current selectivity is far from optimal, especially for demersal stocks. The European Common Fisheries Policy that has assisted in improving the state of NE Atlantic fish stocks in the past 10 years has failed to deliver similar results for Mediterranean stocks managed under the same policy. Limiting juvenile exploitation, advancing management plans, and strengthening compliance, control, and enforcement could promote fisheries sustainability in the Mediterranean.
Transplant - bone marrow; Stem cell transplant; Hematopoietic stem cell transplant; Reduced intensity nonmyeloablative transplant; Mini transplant; Allogenic bone marrow transplant; Autologous bone marrow transplant; ...
A genetic stock certification assay was developed to distinguish Russian honey bees from other European stocks that are commercially produced in the United States. A total of 11 microsatellite and 5 SNP loci were used. Loci were selected for relatively high levels of homogeneity within each group an...
Armstrong, Michelle Hine; Piercey, Victor I.; Greene-Hunley, Stephanie
This article describes two different projects using the stock market as a context for learning. For both projects, students "bought" shares in individual companies, tracked stock prices for a period of time, and then "sold" their shares at a gain or loss. The projects are adaptable for students in late elementary school through…
Goda, Gopi Shah; Shoven, John B.; Slavov, Sita Nataraj
Media reports predicted that the stock market decline in October 2008 would cause changes in retirement intentions, due to declines in retirement assets. We use panel data from the Health and Retirement Study to investigate the relationship between stock market performance and retirement intentions during 1998-2008, a period that includes the…
... 25 Indians 2 2013-04-01 2013-04-01 false Stocking rate. 700.717 Section 700.717 Indians THE OFFICE OF NAVAJO AND HOPI INDIAN RELOCATION COMMISSION OPERATIONS AND RELOCATION PROCEDURES New Lands Grazing § 700.717 Stocking rate. The Commissioner will determine livestock carrying capacity for...
... 25 Indians 2 2010-04-01 2010-04-01 false Stocking rate. 700.717 Section 700.717 Indians THE OFFICE OF NAVAJO AND HOPI INDIAN RELOCATION COMMISSION OPERATIONS AND RELOCATION PROCEDURES New Lands Grazing § 700.717 Stocking rate. The Commissioner will determine livestock carrying capacity for...
... 25 Indians 2 2011-04-01 2011-04-01 false Stocking rate. 700.717 Section 700.717 Indians THE OFFICE OF NAVAJO AND HOPI INDIAN RELOCATION COMMISSION OPERATIONS AND RELOCATION PROCEDURES New Lands Grazing § 700.717 Stocking rate. The Commissioner will determine livestock carrying capacity for...
... 25 Indians 2 2012-04-01 2012-04-01 false Stocking rate. 700.717 Section 700.717 Indians THE OFFICE OF NAVAJO AND HOPI INDIAN RELOCATION COMMISSION OPERATIONS AND RELOCATION PROCEDURES New Lands Grazing § 700.717 Stocking rate. The Commissioner will determine livestock carrying capacity for...
... 25 Indians 2 2014-04-01 2014-04-01 false Stocking rate. 700.717 Section 700.717 Indians THE OFFICE OF NAVAJO AND HOPI INDIAN RELOCATION COMMISSION OPERATIONS AND RELOCATION PROCEDURES New Lands Grazing § 700.717 Stocking rate. The Commissioner will determine livestock carrying capacity for...
Sun, Xiao-Qian; Cheng, Xue-Qi; Shen, Hua-Wei; Wang, Zhao-Yang
Manipulation is an important issue for both developed and emerging stock markets. For the study of manipulation, it is critical to analyze investor behavior in the stock market. In this paper, an analysis of the full transaction records of over a hundred stocks in a one-year period is conducted. For each stock, a trading network is constructed to characterize the relations among its investors. In trading networks, nodes represent investors and a directed link connects a stock seller to a buyer with the total trade size as the weight of the link, and the node strength is the sum of all edge weights of a node. For all these trading networks, we find that the node degree and node strength both have tails following a power-law distribution. Compared with non-manipulated stocks, manipulated stocks have a high lower bound of the power-law tail, a high average degree of the trading network and a low correlation between the price return and the seller-buyer ratio. These findings may help us to detect manipulated stocks.
Li, Shouwei; Zhuang, Yangyang; He, Jianmin
In this article, we propose a method to analyze the stock market stability based on diffusion entropy, and conduct an empirical analysis of Dow Jones Industrial Average. Empirical results show that this method can reflect the volatility and extreme cases of the stock market.
Discusses the advantages of using the stock market to add new dimensions to social studies classes. Suggests that changes in society will make knowledge of financial markets essential for students. Includes two lesson plans with handouts that use the Disney company and changes in the operation of the stock market to capture student interest. (DK)
The trade of a fixed stock can be regarded as the basic process that measures its momentary price. The stock price is exactly known only at the time of sale when the stock is between traders, that is, only in the case when the owner is unknown. We show that the stock price can be better described by a function indicating at any moment of time the probabilities for the possible values of price if a transaction takes place. This more general description contains partial information on the stock price, but it also contains partial information on the stock owner. By following the analogy with quantum mechanics, we assume that the time evolution of the function describing the stock price can be described by a Schroedinger type equation.
The trade of a fixed stock can be regarded as the basic process that measures its momentary price. The stock price is exactly known only at the time of sale when the stock is between traders, that is, only in the case when the owner is unknown. We show that the stock price can be better described by a function indicating at any moment of time the probabilities for the possible values of price if a transaction takes place. This more general description contains partial information on the stock price, but it also contains partial information on the stock owner. By following the analogy with quantum mechanics, we assume that the time evolution of the function describing the stock price can be described by a Schrödinger type equation.
Bastos, João A.; Caiado, Jorge
This study investigates the presence of deterministic dependencies in international stock markets using recurrence plots and recurrence quantification analysis (RQA). The results are based on a large set of free float-adjusted market capitalization stock indices, covering a period of 15 years. The statistical tests suggest that the dynamics of stock prices in emerging markets is characterized by higher values of RQA measures when compared to their developed counterparts. The behavior of stock markets during critical financial events, such as the burst of the technology bubble, the Asian currency crisis, and the recent subprime mortgage crisis, is analyzed by performing RQA in sliding windows. It is shown that during these events stock markets exhibit a distinctive behavior that is characterized by temporary decreases in the fraction of recurrence points contained in diagonal and vertical structures.
... Articles References and abstracts from MEDLINE/PubMed (National Library of Medicine) Article: The Arthroscopic Latarjet A Bony Solution for a Bony Injury. Article: Managing Acetabular Defects in Total Hip Arthroplasty. Article: The ...
... Feeding Your 1- to 2-Year-Old Broken Bones KidsHealth > For Parents > Broken Bones Print A A ... bone fragments in place. When Will a Broken Bone Heal? Fractures heal at different rates, depending upon ...
Bone biopsy; Biopsy - bone ... the cut, then pushed and twisted into the bone. Once the sample is obtained, the needle is ... sample is sent to a lab for examination. Bone biopsy may also be done under general anesthesia ...
A bone biopsy is performed by making a small incision into the skin. A biopsy needle retrieves a sample of bone and it ... examination. The most common reasons for bone lesion biopsy are to distinguish between benign and malignant bone ...
... amputation. This is called limb-salvage or limb-sparing surgery . In going over treatment options, it is ... 2016 Treating Bone Cancer Surgery for Bone Cancer Radiation Therapy for Bone Cancer Chemotherapy for Bone Cancer Targeted ...
... Room? What Happens in the Operating Room? Broken Bones KidsHealth > For Kids > Broken Bones Print A A ... sticking through the skin . What Happens When a Bone Breaks? It hurts to break a bone! It's ...
Smolders, José M H; Pakvis, Dean F; Hendrickx, Baudewijn W; Verdonschot, Nico; van Susante, Job L C
A randomized controlled trial was performed to evaluate acetabular bone mineral density (BMD) changes after hip resurfacing (RHA) versus an established conventional total hip arthroplasty (THA). A total of 71 patients were allocated randomly to receive either an RHA press-fit cobalt-chromium cup (n=38) or a THA with a threaded titanium cup and polyethylene-metal-inlay insert (n=33). The BMD in five separate periacetabular regions of interest (ROI) was prospectively quantified preoperative until 24 months. We conclude that, in contrast to our hypothesis, periacetabular BMD was better preserved after RHA than after placement of a conventional THA. Long term follow-up studies are necessary to see whether this benefit in bone preservation sustains over longer time periods and whether it is turned into clinical benefits at future revision surgery.
Gündüz, Güngör; Gündüz, Yalin
The scattering diagram of a stock index results in a complex network structure, which can be used to analyze the viscoelastic properties of the index. The change along x- or y-direction of the diagram corresponds to purely elastic (or spring like) movement whereas the diagonal change at an angle of 45° corresponds to purely viscous (or dashpot like) movement. The viscous component pushes the price from its current value to any other value, while the elastic component acts like a restoring force. Four indices, namely, DJI, S&P-500, NASDAQ-100, and NASDAQ-composite were studied for the period of 2001-2009. NASDAQ-composite displayed very high elasticity while NASDAQ-100 displayed the highest fluidity in the time period considered. The fluidity of DJI and S&P-500 came out to be close to each other, and they are almost the same in the second half of the period.
Razak, Ruzanna Ab; Ismail, Noriszura
Recent studies have found that Islamic stocks are dependent on conventional stocks and they appear to be more risky. In Asia, particularly in Islamic countries, research on dependence involving Islamic and non-Islamic stock markets is limited. The objective of this study is to investigate the dependence between financial times stock exchange Hijrah Shariah index and conventional stocks (EMAS and KLCI indices). Using the copula approach and a time series model for each marginal distribution function, the copula parameters were estimated. The Elliptical copula was selected to present the dependence structure of each pairing of the Islamic stock and conventional stock. Specifically, the Islamic versus conventional stocks (Shariah-EMAS and Shariah-KLCI) had lower dependence compared to conventional versus conventional stocks (EMAS-KLCI). These findings suggest that the occurrence of shocks in a conventional stock will not have strong impact on the Islamic stock.
Matsumoto, Mikio; Baba, Tomonori; Ochi, Hironori; Ozaki, Yu; Watari, Taiji; Homma, Yasuhiro; Kaneko, Kazuo
Introduction: For cases with extensive acetabular bone defects, we perform surgery combining the Kerboull-type (KT) plate and bone graft through direct anterior approach (DAA) in primary total hip arthroplasty (THA) requiring acetabular reconstruction as minimally invasive surgery. This paper provides the details of the surgical procedure. Methods: The basic structure of the Kerboull-type plate is a cruciform plate. Since the hook of the Kerboull-type plate has to be applied to the tear drop, a space for it was exposed. The tear drop is located in the anterior lower region in surgery through DAA in supine position. It was also confirmed by fluoroscopy as needed. The bone grafting was performed using an auto- or allogeneic femoral head for bone defects in the weight-bearing region of the hip joint. Results: Of 563 patients who underwent primary THA between 2012 and 2014, THA using the KT plate through DAA was performed in 21 patients (3.7%). The mean duration of postoperative follow-up was 31.8 months. The mean operative time was 188.4 min, and the mean blood loss was 770 g. The patients became able to walk independently after 2.4 days on average (1–4 days). On clinical evaluation, the modified Harris Hip Score was 45.6 ± 12.4 before surgery, and it was significantly improved to 85.3 ± 8.97 on the final follow-up. Discussion: DAA is a true intermuscular approach capable of conserving soft tissue. Since it is applied in a supine position, fluoroscopy can be readily used, and it was very useful to accurately place the plate. PMID:28287388
Ferreira, Nuno B.; Menezes, Rui; Mendes, Diana A.
Recent studies show that a negative shock in stock prices will generate more volatility than a positive shock of similar magnitude. The aim of this paper is to appraise the hypothesis under which the conditional mean and the conditional variance of stock returns are asymmetric functions of past information. We compare the results for the Portuguese Stock Market Index PSI 20 with six other Stock Market Indices, namely the SP 500, FTSE 100, DAX 30, CAC 40, ASE 20, and IBEX 35. In order to assess asymmetric volatility we use autoregressive conditional heteroskedasticity specifications known as TARCH and EGARCH. We also test for asymmetry after controlling for the effect of macroeconomic factors on stock market returns using TAR and M-TAR specifications within a VAR framework. Our results show that the conditional variance is an asymmetric function of past innovations raising proportionately more during market declines, a phenomenon known as the leverage effect. However, when we control for the effect of changes in macroeconomic variables, we find no significant evidence of asymmetric behaviour of the stock market returns. There are some signs that the Portuguese Stock Market tends to show somewhat less market efficiency than other markets since the effect of the shocks appear to take a longer time to dissipate.
Tse, Man Kit
Viewing the stock market as a self-organized system, Sornette and Johansen introduced physics-based models to study the dynamics of stock market crashes from the perspective of complex systems. This involved modeling stock market Indices using a mathematical power law exhibiting log-periodicity as the system approaches a market crash, which acts like a critical point in a thermodynamic system. In this dissertation, I aim to investigate stock indices to determine whether or not they exhibit log-periodic oscillations, according to the models proposed by Sornette, as they approach a crash. In addition to analyzing stock market crashes in the frequency domain using the discrete Fourier transform and the Lomb-Scargle periodogram, I perform a detailed analysis of the stock market crash models through parameter estimation and model testing. I find that the probability landscapes have a complex topography and that there is very little evidence that these phase transition-based models accurately describe stock market crashes.
Cassar-Gheiti, Adrian J; Collins, Dennis; McCarthy, Tom
The use of alternative bearing surfaces for total hip arthroplasty has become popular to minimize wear and increase longevity, especially in young patients. Oxidized zirconium (Oxinium; Smith & Nephew, Memphis, Tennessee) femoral heads were introduced in the past decade for use in total hip arthroplasty. The advantages of oxidized zirconium include less risk of fracture compared with traditional ceramic heads. This case report describes a patient with a history of bilateral avascular necrosis of the femoral head after chemotherapy for acute lymphoblastic leukemia. Nonoperative management of avascular necrosis failed, and the patient was treated with bilateral total hip arthroplasty. The patient was followed at regular intervals and had slow eccentric polyethylene wear during a 10-year period. After 10 years, the patient had accelerated wear, with femoral and acetabular bone changes as a result of Oxinium and ultrahigh-molecular-weight polyethylene wear during a 6-month period. This article highlights the unusual accelerated bone changes that occurred as a result of Oxinium wear particles.
Conventionally, the bonding strength of bone-cement interface is obtained by mechanical strength testing which tends to produce large variability between specimens and test methods. In this work, interfacial fracture toughness of synthetic bone-cement interface has been determined using sandwiched Brazilian disk specimens. Experiments were carried out under selected loading angles from 0 to 25 degrees to achieve full loading conditions from mode I to mode II. Solutions for complex stress intensity factors as well as strain energy release rates were obtained for a sandwich disk with a finite interlayer using the finite element method. Phase angles were obtained at a fixed distance to the crack tip. The fracture loads were obtained from the load displacement curves and the values of interfacial fracture toughness were calculated from the fracture loads and the finite element J-integral solutions. The implication of this information on the assessment of fixation in acetabular replacements was discussed in the light of in-vitro fatigue testing of implanted acetabula. PMID:19325935
Conventionally, the bonding strength of bone-cement interface is obtained by mechanical strength testing which tends to produce large variability between specimens and test methods. In this work, interfacial fracture toughness of synthetic bone-cement interface has been determined using sandwiched Brazilian disk specimens. Experiments were carried out under selected loading angles from 0 to 25 degrees to achieve full loading conditions from mode I to mode II. Solutions for complex stress intensity factors as well as strain energy release rates were obtained for a sandwich disk with a finite interlayer using the finite element method. Phase angles were obtained at a fixed distance to the crack tip. The fracture loads were obtained from the load displacement curves and the values of interfacial fracture toughness were calculated from the fracture loads and the finite element J-integral solutions. The implication of this information on the assessment of fixation in acetabular replacements was discussed in the light of in-vitro fatigue testing of implanted acetabula.
AD-A241 855 NAVAL POSTGRADUATE SCHOOL Monterey, California ,.V ST A C -,. S ’GR t- D TIQ : 0T.281 " THESIS & NAVY STOCK ACCOUNT (NSA: ATEP.AL...Stock Account (NSA) Material Expenditure Errors 12, PERSONAL AUTHOR(S) Magsombol, Anacleto M. 13a TYPE OF REPORT 13b TIME COVERED 14 DATE OF REPORT (Year...Continue on reverse if necessary andl identify by block number) FIELD GROUP SUB-GROUP Expenditures, Navy Stock Account (NSA), Recon- ciliation Process
Chen, Chun-Chih; Chen, Chin-Shyan; Liu, Tsai-Ching; Lin, Ying-Tzu
This paper investigates the impact of stock market movement on incidences of stroke utilizing population-based aggregate data in Taiwan. Using the daily data from the Taiwan Stock Exchange Capitalization Weighted Stock Index and from the National Health Insurance Research Database during 2001/1/1-2007/12/31, which consist of 2556 observations, we examine the effects of stock market on stroke incidence - the level effect and the daily change effects. In general, we find that both a low stock index level and a daily fall in the stock index are associated with greater incidences of stroke. We further partition the data on sex and age. The level effect is found to be significant for either gender, in the 45-64 and 65 ≥ age groups. In addition, two daily change effects are found to be significant for males and the elderly. Although stockholdings can increase wealth, they can also increase stroke incidence, thereby representing a cost to health.
Vasconcellos, Letícia A; Blando, Eduardo; Souto, André A; Oliveira, Marilia G; Woitchunas, Gilséia F P; Hübler, Roberto
The use of multi-component femoral implants to replace the femur head and re-establish bone motion has been widespread since the 70s. Frequently these implants have spherical metallic heads made of, for example, 316-L stainless steel or Cr-Co alloys, which allow rotational motion towards a polymeric component (UHMWPE). One of the major causes of implant rejection is the generation of UHMWPE debris on the surface between the implant head and the polymeric component. The gamma ray sterilization of implants and the periodical X-ray medical control could contribute to premature degradation of the polymeric surface, resulting in increased wear and shortened lifetime of the implant. In this work we study the degradation degree of the polymeric UHMWPE component as function of the X-ray dose. The elasto-plastic deformation and recovery were carried out by means of a nanohardness tester equipment and the polymer degradation was measured using a fast Fourier transform infra-red (FT-IR) equipment. The results show the compromise among the irradiation doses, the surface oxidation and the mechanical properties of the samples.
Sherman, Thomas I.; Marcel, John J.; Postma, William
Patients with mixed-type femoroacetabular impingement syndrome often have concomitant chondrolabral pathology in addition to the characteristic cam and pincer lesions. Unfortunately, these patients are typically young, and the pathology is localized to the weight-bearing dome of the acetabulum. Complete preoperative characterization of labral and cartilage lesions is often not possible even with advanced imaging techniques, and the full extent of the injury may not be appreciated without direct arthroscopic visualization. Thus management decisions regarding intra-articular pathology may not be possible until the time of surgery. Often, the cartilage and labral pathology in these young patients is part of a contiguous complex of tissue that separates from the underlying subchondral bone. We present an arthroscopic management technique for young patients with this pattern of injury. This includes limited debridement of loose labral and chondral tissue, labral repair to restore the suction-seal effect, microfracture to promote reparative tissue formation, and takedown of the underlying pathoanatomic cam and pincer lesions. PMID:25685678
Liu, Z Q; Liew, H L; Clement, J G; Thomas, C D
Characteristics of microscopic structures in bone cross sections carry essential clues in age determination in forensic science and in the study of age-related bone developments and bone diseases. Analysis of bone cross sections represents a major area of research in bone biology. However, traditional approaches in bone biology have relied primarily on manual processes with very limited number of bone samples. As a consequence, it is difficult to reach reliable and consistent conclusions. In this paper we present an image processing system that uses microstructural and relational knowledge present in the bone cross section for bone image segmentation. This system automates the bone image analysis process and is able to produce reliable results based on quantitative measurements from a large number of bone images. As a result, using large databases of bone images to study the correlation between bone structural features and age-related bone developments becomes feasible.
... extent that the fair market value of the stock rights, on the date distributed to the shareholder, would... the definition of section 306 stock any stock (except as provided in section 306(c)(1)(B)) the basis... classified if the basis of such stock is determined by reference to its fair market value on the date of...
... 43 Public Lands: Interior 2 2012-10-01 2012-10-01 false Access to stock watering places. 3815.5... Mineral Locations in Stock Driveway Withdrawals § 3815.5 Access to stock watering places. No watering places shall be inclosed, nor proper and lawful access of stock thereto prevented, nor the watering...
... 43 Public Lands: Interior 2 2014-10-01 2014-10-01 false Protection of stock. 3815.4 Section 3815.4... Locations in Stock Driveway Withdrawals § 3815.4 Protection of stock. All excavations and other mining work... prevent the same from being a menace to stock on the land....
... 12 Banks and Banking 1 2013-01-01 2013-01-01 false Combinations involving Federal stock... FEDERAL STOCK ASSOCIATIONS-INCORPORATION, ORGANIZATION, AND CONVERSION § 152.13 Combinations involving Federal stock associations. (a) Scope and authority. Federal stock associations may enter...
... 12 Banks and Banking 5 2011-01-01 2011-01-01 false Combinations involving Federal stock... FEDERAL STOCK ASSOCIATIONS-INCORPORATION, ORGANIZATION, AND CONVERSION § 552.13 Combinations involving Federal stock associations. (a) Scope and authority. Federal stock associations may enter...
... 12 Banks and Banking 6 2013-01-01 2012-01-01 true Combinations involving Federal stock... FEDERAL STOCK ASSOCIATIONS-INCORPORATION, ORGANIZATION, AND CONVERSION § 552.13 Combinations involving Federal stock associations. (a) Scope and authority. Federal stock associations may enter...
... 12 Banks and Banking 8 2012-01-01 2012-01-01 false Issuance of capital stock. 931.2 Section 931.2... STANDARDS FEDERAL HOME LOAN BANK CAPITAL STOCK § 931.2 Issuance of capital stock. (a) In general. A Bank may issue either one or both classes of its capital stock (including subclasses), as authorized by §...
... 12 Banks and Banking 1 2014-01-01 2014-01-01 false Reverse stock splits. 7.2023 Section 7.2023... Corporate Practices § 7.2023 Reverse stock splits. (a) Authority to engage in reverse stock splits. A national bank may engage in a reverse stock split if the transaction serves a legitimate corporate...
... 12 Banks and Banking 7 2011-01-01 2011-01-01 false Adjustments in stock holdings. 1263.22 Section... Stock Requirements § 1263.22 Adjustments in stock holdings. (a) Adjustment in general. A Bank may from time to time increase or decrease the amount of stock any member is required to hold. (b)(1)...
... 12 Banks and Banking 8 2013-01-01 2013-01-01 false Issuance of capital stock. 931.2 Section 931.2... STANDARDS FEDERAL HOME LOAN BANK CAPITAL STOCK § 931.2 Issuance of capital stock. (a) In general. A Bank may issue either one or both classes of its capital stock (including subclasses), as authorized by §...
... 43 Public Lands: Interior 2 2011-10-01 2011-10-01 false Protection of stock. 3815.4 Section 3815.4... Locations in Stock Driveway Withdrawals § 3815.4 Protection of stock. All excavations and other mining work... prevent the same from being a menace to stock on the land....
... 12 Banks and Banking 6 2014-01-01 2012-01-01 true Combinations involving Federal stock... FEDERAL STOCK ASSOCIATIONS-INCORPORATION, ORGANIZATION, AND CONVERSION § 552.13 Combinations involving Federal stock associations. (a) Scope and authority. Federal stock associations may enter...
... 43 Public Lands: Interior 2 2011-10-01 2011-10-01 false Access to stock watering places. 3815.5... Mineral Locations in Stock Driveway Withdrawals § 3815.5 Access to stock watering places. No watering places shall be inclosed, nor proper and lawful access of stock thereto prevented, nor the watering...
... 47 Telecommunication 3 2012-10-01 2012-10-01 false Cost of preferred stock. 65.303 Section 65.303... stock. The formula for determining the cost of preferred stock is: ER01JN95.001 Where: “Total Annual Preferred Dividends” is the total dividends on preferred stock for the most recent two years for all...
... 12 Banks and Banking 6 2012-01-01 2012-01-01 false Combinations involving Federal stock... FEDERAL STOCK ASSOCIATIONS-INCORPORATION, ORGANIZATION, AND CONVERSION § 552.13 Combinations involving Federal stock associations. (a) Scope and authority. Federal stock associations may enter...
... 12 Banks and Banking 8 2014-01-01 2014-01-01 false Minimum investment in capital stock. 931.3... CAPITAL STANDARDS FEDERAL HOME LOAN BANK CAPITAL STOCK § 931.3 Minimum investment in capital stock. (a) A Bank shall require each member to maintain a minimum investment in the capital stock of the Bank,...
... 41 Public Contracts and Property Management 2 2011-07-01 2007-07-01 true Disposition of stock. 101...-Elimination of Items From Inventory § 101-27.406 Disposition of stock. Stocks of slow-moving items which are... this section, shall be taken, as necessary, to remove stocks of inactive items from inventory....
... 12 Banks and Banking 9 2012-01-01 2012-01-01 false Adjustments in stock holdings. 1263.22 Section... Stock Requirements § 1263.22 Adjustments in stock holdings. (a) Adjustment in general. A Bank may from time to time increase or decrease the amount of stock any member is required to hold. (b)(1)...
... 12 Banks and Banking 7 2010-01-01 2010-01-01 false Adjustments in stock holdings. 925.22 Section... ASSOCIATES MEMBERS OF THE BANKS Stock Requirements § 925.22 Adjustments in stock holdings. (a) Adjustment in general. A Bank may from time to time increase or decrease the amount of stock any member is required...
... 43 Public Lands: Interior 2 2012-10-01 2012-10-01 false Protection of stock. 3815.4 Section 3815.4... Locations in Stock Driveway Withdrawals § 3815.4 Protection of stock. All excavations and other mining work... prevent the same from being a menace to stock on the land....
... 12 Banks and Banking 1 2013-01-01 2013-01-01 false Reverse stock splits. 7.2023 Section 7.2023... Corporate Practices § 7.2023 Reverse stock splits. (a) Authority to engage in reverse stock splits. A national bank may engage in a reverse stock split if the transaction serves a legitimate corporate...
... 43 Public Lands: Interior 2 2014-10-01 2014-10-01 false Access to stock watering places. 3815.5... Mineral Locations in Stock Driveway Withdrawals § 3815.5 Access to stock watering places. No watering places shall be inclosed, nor proper and lawful access of stock thereto prevented, nor the watering...
... 26 Internal Revenue 4 2013-04-01 2013-04-01 false Section 306 stock defined. 1.306-3 Section 1.306... (CONTINUED) INCOME TAXES (CONTINUED) Effects on Recipients § 1.306-3 Section 306 stock defined. (a) For the purpose of subchapter C, chapter 1 of the code, the term section 306 stock means stock which meets...
... 26 Internal Revenue 4 2012-04-01 2012-04-01 false Section 306 stock defined. 1.306-3 Section 1.306... (CONTINUED) INCOME TAXES (Continued) Effects on Recipients § 1.306-3 Section 306 stock defined. (a) For the purpose of subchapter C, chapter 1 of the code, the term section 306 stock means stock which meets...
... 47 Telecommunication 3 2011-10-01 2011-10-01 false Cost of preferred stock. 65.303 Section 65.303... stock. The formula for determining the cost of preferred stock is: ER01JN95.001 Where: “Total Annual Preferred Dividends” is the total dividends on preferred stock for the most recent two years for all...
... 26 Internal Revenue 4 2011-04-01 2011-04-01 false Section 306 stock defined. 1.306-3 Section 1.306... (CONTINUED) INCOME TAXES Effects on Recipients § 1.306-3 Section 306 stock defined. (a) For the purpose of subchapter C, chapter 1 of the code, the term section 306 stock means stock which meets the requirements...
... 12 Banks and Banking 7 2011-01-01 2011-01-01 false Issuance of capital stock. 931.2 Section 931.2... STANDARDS FEDERAL HOME LOAN BANK CAPITAL STOCK § 931.2 Issuance of capital stock. (a) In general. A Bank may issue either one or both classes of its capital stock (including subclasses), as authorized by §...
... 26 Internal Revenue 4 2014-04-01 2014-04-01 false Section 306 stock defined. 1.306-3 Section 1.306... (CONTINUED) INCOME TAXES (CONTINUED) Effects on Recipients § 1.306-3 Section 306 stock defined. (a) For the purpose of subchapter C, chapter 1 of the code, the term section 306 stock means stock which meets...
... 12 Banks and Banking 7 2011-01-01 2011-01-01 false Minimum investment in capital stock. 931.3... CAPITAL STANDARDS FEDERAL HOME LOAN BANK CAPITAL STOCK § 931.3 Minimum investment in capital stock. (a) A Bank shall require each member to maintain a minimum investment in the capital stock of the Bank,...
... 12 Banks and Banking 10 2014-01-01 2014-01-01 false Adjustments in stock holdings. 1263.22 Section... Stock Requirements § 1263.22 Adjustments in stock holdings. (a) Adjustment in general. A Bank may from time to time increase or decrease the amount of stock any member is required to hold. (b)(1)...
... 47 Telecommunication 3 2013-10-01 2013-10-01 false Cost of preferred stock. 65.303 Section 65.303... stock. The formula for determining the cost of preferred stock is: ER01JN95.001 Where: “Total Annual Preferred Dividends” is the total dividends on preferred stock for the most recent two years for all...
... 41 Public Contracts and Property Management 2 2013-07-01 2012-07-01 true Disposition of stock. 101...-Elimination of Items From Inventory § 101-27.406 Disposition of stock. Stocks of slow-moving items which are... this section, shall be taken, as necessary, to remove stocks of inactive items from inventory....
... 41 Public Contracts and Property Management 2 2014-07-01 2012-07-01 true Disposition of stock. 101...-Elimination of Items From Inventory § 101-27.406 Disposition of stock. Stocks of slow-moving items which are... this section, shall be taken, as necessary, to remove stocks of inactive items from inventory....
... 12 Banks and Banking 8 2014-01-01 2014-01-01 false Issuance of capital stock. 931.2 Section 931.2... STANDARDS FEDERAL HOME LOAN BANK CAPITAL STOCK § 931.2 Issuance of capital stock. (a) In general. A Bank may issue either one or both classes of its capital stock (including subclasses), as authorized by §...
... 12 Banks and Banking 1 2012-01-01 2012-01-01 false Combinations involving Federal stock... FEDERAL STOCK ASSOCIATIONS-INCORPORATION, ORGANIZATION, AND CONVERSION § 152.13 Combinations involving Federal stock associations. (a) Scope and authority. Federal stock associations may enter...
... 43 Public Lands: Interior 2 2013-10-01 2013-10-01 false Access to stock watering places. 3815.5... Mineral Locations in Stock Driveway Withdrawals § 3815.5 Access to stock watering places. No watering places shall be inclosed, nor proper and lawful access of stock thereto prevented, nor the watering...
... 12 Banks and Banking 8 2012-01-01 2012-01-01 false Minimum investment in capital stock. 931.3... CAPITAL STANDARDS FEDERAL HOME LOAN BANK CAPITAL STOCK § 931.3 Minimum investment in capital stock. (a) A Bank shall require each member to maintain a minimum investment in the capital stock of the Bank,...
... 41 Public Contracts and Property Management 2 2012-07-01 2012-07-01 false Disposition of stock...-Elimination of Items From Inventory § 101-27.406 Disposition of stock. Stocks of slow-moving items which are... this section, shall be taken, as necessary, to remove stocks of inactive items from inventory....
... 12 Banks and Banking 9 2013-01-01 2013-01-01 false Adjustments in stock holdings. 1263.22 Section... Stock Requirements § 1263.22 Adjustments in stock holdings. (a) Adjustment in general. A Bank may from time to time increase or decrease the amount of stock any member is required to hold. (b)(1)...
... 47 Telecommunication 3 2014-10-01 2014-10-01 false Cost of preferred stock. 65.303 Section 65.303... stock. The formula for determining the cost of preferred stock is: ER01JN95.001 Where: “Total Annual Preferred Dividends” is the total dividends on preferred stock for the most recent two years for all...
... 12 Banks and Banking 1 2014-01-01 2014-01-01 false Combinations involving Federal stock... FEDERAL STOCK ASSOCIATIONS-INCORPORATION, ORGANIZATION, AND CONVERSION § 152.13 Combinations involving Federal stock associations. (a) Scope and authority. Federal stock associations may enter...
... 12 Banks and Banking 8 2013-01-01 2013-01-01 false Minimum investment in capital stock. 931.3... CAPITAL STANDARDS FEDERAL HOME LOAN BANK CAPITAL STOCK § 931.3 Minimum investment in capital stock. (a) A Bank shall require each member to maintain a minimum investment in the capital stock of the Bank,...
... 41 Public Contracts and Property Management 3 2014-01-01 2014-01-01 false Stock control. 109-27...-INVENTORY MANAGEMENT 27.50-Inventory Management Policies, Procedures, and Guidelines § 109-27.5003 Stock control. (a) Stock control shall be maintained on the basis of stock record accounts of inventories...
... 12 Banks and Banking 1 2012-01-01 2012-01-01 false Reverse stock splits. 7.2023 Section 7.2023... Corporate Practices § 7.2023 Reverse stock splits. (a) Authority to engage in reverse stock splits. A national bank may engage in a reverse stock split if the transaction serves a legitimate corporate...
... 43 Public Lands: Interior 2 2013-10-01 2013-10-01 false Protection of stock. 3815.4 Section 3815.4... Locations in Stock Driveway Withdrawals § 3815.4 Protection of stock. All excavations and other mining work... prevent the same from being a menace to stock on the land....
... 12 Banks and Banking 7 2010-01-01 2010-01-01 false Issuance and form of stock. 925.21 Section 925... ASSOCIATES MEMBERS OF THE BANKS Stock Requirements § 925.21 Issuance and form of stock. (a) A Bank shall issue to each new member, as of the effective date of membership, stock in the member's name for...
Maruszewski, Richard F., Jr.
Investors are interested in the volatility of a stock for various reasons. One investor may desire to purchase a low volatility stock for peace of mind. Another may be interested in a high volatility stock in order to have the opportunity to buy low and sell high as the price of the stock oscillates. This author had the fortunate timing of reading…
Wilkinson, A Graham; Wilkinson, Sally; Elton, Robert A
Published maturation curves for bony acetabular roof or α angle (AA) and percentage femoral head cover (FHC) with age are sparse. We aimed to determine typical values for AA and FHC in 2236 infants referred to a selective ultrasound screening programme. There was increase in the values of first measurement of AA and FHC related to the logarithm of age. Males had greater values than females (P<0.001) and right hips had greater values than left (P<0.001) for both measurements. Significant side differences have not been reported previously. Treatment decisions should be made on the basis of sex, side and age-specific data.
Diederichs, Chad; Heath, Alana; Hareendranathan, Abhilash R; Zonoobi, Dornoosh; Kuntze, Gregor; Dulai, Sukhdeep; Mabee, Myles G; Ronsky, Janet L; Jaremko, Jacob L
Current imaging diagnosis of developmental dysplasia of the hip (DDH) in infancy relies on 2-D ultrasound (US), which is highly operator-dependent. 3-D US offers more complete, and potentially more reliable, imaging of infant hip geometry. We sought to validate the fidelity of acetabular surface models obtained by 3-D US against those obtained concurrently by magnetic resonance imaging (MRI). 3-D US and MRI scans were performed on the same d in 20 infants with normal to severely dysplastic hips (mean age, 57 d; range 13-181 d). 3-D US was performed by two observers using a Philips VL13-5 probe. Coronal 3-D multi-echo data image combination (MEDIC) magnetic resonance (MR) images (1-mm slice thickness) were obtained, usually without sedation, in a 1.5 T Siemens unit. Acetabular surface models were generated for 40 hips from 3-D US and MRI using semi-automated tracing software, separately by three observers. For each hip, the 3-D US and MRI models were co-registered to overlap as closely as possible using Amira software, and the root mean square (RMS) distances between points on the models were computed. 3-D US scans took 3.2 s each. Inter-modality variability was visually minimal. Mean RMS distance between corresponding points on the acetabular surface at 3-D US and MRI was 0.4 ± 0.3 mm, with 95% confidence interval <1 mm. Mean RMS errors for inter-observer and intra-observer comparisons were significantly less for 3-D US than for MRI, while inter-scan and inter-modality comparisons showed no significant difference. Acetabular geometry was reproduced by 3-D US surface models within 1 mm of the corresponding 3-D MRI surface model, and the 3-D US models were more reliable. This validates the fidelity of 3-D US modeling and encourages future use of 3-D US in assessing infant acetabulum anatomy, which may be useful to detect and monitor treatment of hip dysplasia.
This statement establishes general principles the Agency generally will apply in determining whether and under what conditions to allow the sale and use of existing stocks of pesticides for which the registration has been amended, canceled, or suspended.
Wagner, F.; Milaković, M.; Alfarano, S.
Stochastic volatility models decompose the time series of financial returns into the product of a volatility factor and an iid noise factor. Assuming a slow dynamic for the volatility factor, we show via nonparametric tests that both the index as well as its individual stocks share a common volatility factor. While the noise component is Gaussian for the index, individual stock returns turn out to require a leptokurtic noise. Thus we propose a two-component model for stocks, given by the sum of Gaussian noise, which reflects market-wide fluctuations, and Laplacian noise, which incorporates firm-specific factors such as firm profitability or growth performance, both of which are known to be Laplacian distributed. In the case of purely Gaussian noise, the chi-squared probability for the density of individual stock returns is typically on the order of 10-20, while it increases to values of O(1) by adding the Laplace component.
Yang, Jae-Suk; Kwak, Wooseop; Kaizoji, Taisei; Kim, In-Mook
We study the temporal evolutions of three stock markets; Standard and Poor's 500 index, Nikkei 225 Stock Average, and the Korea Composite Stock Price Index. We observe that the probability density function of the log-return has a fat tail but the tail index has been increasing continuously in recent years. We have also found that the variance of the autocorrelation function, the scaling exponent of the standard deviation, and the statistical complexity decrease, but that the entropy density increases as time goes over time. We introduce a modified microscopic spin model and simulate the model to confirm such increasing and decreasing tendencies in statistical quantities. These findings indicate that these three stock markets are becoming more efficient.
... dividends, stock splits or exercise of rights. 225.103 Section 225.103 Banks and Banking FEDERAL RESERVE... § 225.103 Bank holding company acquiring stock by dividends, stock splits or exercise of rights. (a) The... participate in bank stock splits without the Board's prior approval, and whether such a company may...
... dividends, stock splits or exercise of rights. 225.103 Section 225.103 Banks and Banking FEDERAL RESERVE... holding company acquiring stock by dividends, stock splits or exercise of rights. (a) The Board of... bank stock splits without the Board's prior approval, and whether such a company may exercise,...
... dividends, stock splits or exercise of rights. 225.103 Section 225.103 Banks and Banking FEDERAL RESERVE... § 225.103 Bank holding company acquiring stock by dividends, stock splits or exercise of rights. (a) The... participate in bank stock splits without the Board's prior approval, and whether such a company may...
... dividends, stock splits or exercise of rights. 225.103 Section 225.103 Banks and Banking FEDERAL RESERVE... holding company acquiring stock by dividends, stock splits or exercise of rights. (a) The Board of... bank stock splits without the Board's prior approval, and whether such a company may exercise,...
... 17 Commodity and Securities Exchanges 3 2011-04-01 2011-04-01 false Penny stock disclosure document relating to the penny stock market. 240.15g-2 Section 240.15g-2 Commodity and Securities Exchanges... Section 15(d) of the Act § 240.15g-2 Penny stock disclosure document relating to the penny stock...
... 17 Commodity and Securities Exchanges 4 2014-04-01 2014-04-01 false Penny stock disclosure document relating to the penny stock market. 240.15g-2 Section 240.15g-2 Commodity and Securities Exchanges... Section 15(d) of the Act § 240.15g-2 Penny stock disclosure document relating to the penny stock...
... 17 Commodity and Securities Exchanges 3 2013-04-01 2013-04-01 false Penny stock disclosure document relating to the penny stock market. 240.15g-2 Section 240.15g-2 Commodity and Securities Exchanges... Section 15(d) of the Act § 240.15g-2 Penny stock disclosure document relating to the penny stock...
... 17 Commodity and Securities Exchanges 3 2012-04-01 2012-04-01 false Penny stock disclosure document relating to the penny stock market. 240.15g-2 Section 240.15g-2 Commodity and Securities Exchanges... Section 15(d) of the Act § 240.15g-2 Penny stock disclosure document relating to the penny stock...
... dividends, stock splits or exercise of rights. 225.103 Section 225.103 Banks and Banking FEDERAL RESERVE... holding company acquiring stock by dividends, stock splits or exercise of rights. (a) The Board of... bank stock splits without the Board's prior approval, and whether such a company may exercise,...
Pozzi, Grazia; Stradiotti, Paola; Parra, Cleber Garcia; Zagra, Luigi; Sironi, Sandro; Zerbi, Alberto
To assess the effectiveness of indirect Magnetic Resonance arthrography (i-MRa) in the detection of chondral and labral lesions related to femoro-acetabular impingement (FAI) a series of 21 hip joints in 17 patients with a clinical diagnosis of FAI were examined either with standard MR imaging, i-MRa and direct-MR arthrography (d-MRa). Sensitivity and accuracy of i-MRa in detecting chondral, labral and tardive lesions were calculated and compared with standard MR. The agreement in detecting endoarticular damage between i-MRa and d-MRa and the interobserver agreement was assessed by K statistic (p<0.05). Finally the presence of trocanteric bursitis was evaluated. I-MRa showed higher values of both sensivity and accuracy than standard MR in detecting chondral damage, with an increase to 92% for the first item and 95% for the second. The same was noticed in labrum evaluation with an increase to 88% and 90% respectively. The level of agreement between i-MRa and d-MRa in detection of chondral lesions was excellent, substantial for the labral damage and absolute for early osteoarthritic changes. An excellent interobserver agreement resulted in detection of both chondral and labral damages with i-MRa. In 6 hips (28,5%) we also found the presence of peri-trochanteric soft tissue inflammation that indicated the possibility of extrarticular involvement in FAI. Indirect-MRa can be considered a valid method of assessing endoarticular damage related to FAI, in comparison to d-MRa. It should be performed instead of standard MR if d-MRa is not available.
Sanovich, R; Mehta, U; Abramowicz, S; Widmer, C; Dolwick, M F
The purpose of this study was to report the subjective and objective outcomes of temporomandibular joint (TMJ) replacement with Biomet stock prostheses at a single institution in Florida. In this retrospective study, patients who underwent TMJ replacement using a Biomet stock prosthesis from 2005 to 2012 were analyzed. Subjective (pain, diet) and objective (maximal incisal opening) information was obtained. In addition, a quality of life measure was obtained pre- and postoperatively. Significance was set at <0.01. Thirty-six patients (26 bilateral, 6 left, and 4 right) who underwent TMJ replacement using a Biomet stock prosthesis were eligible for the study. Maximal incisal opening improved from 26.1mm preoperatively to a mean of 34.4mm postoperatively. The pain score decreased from 7.9 preoperatively to a mean of 3.8 postoperatively. Diet restriction decreased from 6.8 preoperatively to a mean of 3.5 postoperatively. Quality of life improved from a median of 4 preoperatively to a postoperative median of 2. Four implants were removed/replaced because of heterotopic bone formation, infection, and/or loose hardware. Follow-up ranged from 6 to 83 months. Overall, TMJ reconstruction using the Biomet stock joint is effective and safe in this patient population.
Ni, G X; Chiu, K Y; Lu, W W; Wang, Y; Zhang, Y G; Hao, L B; Li, Z Y; Lam, W M; Lu, S B; Luk, K D K
Clinical outcome of cemented implants to revision total hip replacement (THR) is not as satisfactory as primary THR, due to the loss of bone stock and normal trabecular pattern. This study evaluated a bioactive bone cement, strontium-containing hydroxyapatite (Sr-HA) bone cement, in a goat revision hip hemi-arthroplasty model, and compared outcomes with polymethylmethacrylate (PMMA) bone cement. Nine months after operation, significantly higher bonding strength was found in the Sr-HA group (3.36+/-1.84 MPa) than in the PMMA bone cement group (1.23+/-0.73 MPa). After detached from the femoral component, the surface of PMMA bone cement mantle was shown relatively smooth, whereas the surface of the Sr-HA bioactive bone cement mantle was uneven, by SEM observation. EDX analysis detected little calcium and no phosphorus on the surface of PMMA bone cement mantle, while high content of calcium (14.03%) and phosphorus (10.37%) was found on the surface of the Sr-HA bone cement mantle. Even higher content of calcium (17.37%) and phosphorus (10.84%) were detected in the concave area. Intimate contact between Sr-HA bioactive bone cement and bone was demonstrated by histological and SEM observation. New bone bonded to the surface of Sr-HA cement and grew along its surface. However, fibrous tissue was observed between PMMA bone cement and bone. The results showed good bioactivity of Sr-HA bioactive bone cement in this revision hip replacement model using goats. This in vivo study also suggested that Sr-HA bioactive bone cement was superior to PMMA bone cement in terms of bone-bonding strength. Use of bioactive bone cement may be a possible solution overcoming problems associated with the use of PMMA bone cement in revision hip replacement.
Chen, Kun; Luo, Peng; Sun, Bianxia; Wang, Huaiqing
According to asset pricing theory, a stock's expected returns are determined by its exposure to systematic risk. In this paper, we propose a new method for analyzing the interaction effects among industries and stocks on stock returns. We construct a complex network based on correlations of abnormal stock returns and use centrality and modularity, two popular measures in social science, to determine the effect of interconnections on industry and stock returns. Supported by previous studies, our findings indicate that a relationship exists between inter-industry closeness and industry returns and between stock centrality and stock returns. The theoretical and practical contributions of these findings are discussed.
Short, Aaron R.; Koralla, Deepthi; Deshmukh, Ameya; Wissel, Benjamin; Stocker, Benjamin; Calhoun, Mark; Dean, David; Winter, Jessica O.
Bone defects can originate from a variety of causes, including trauma, cancer, congenital deformity, and surgical reconstruction. Success of the current “gold standard” treatment (i.e., autologous bone grafts) is greatly influenced by insufficient or inappropriate bone stock. There is thus a critical need for the development of new, engineered materials for bone repair. This review describes the use of natural and synthetic hydrogels as scaffolds for bone tissue engineering. We discuss many of the advantages that hydrogels offer as bone repair materials, including their potential for osteoconductivity, biodegradability, controlled growth factor release, and cell encapsulation. We also discuss the use of hydrogels in composite devices with metals, ceramics, or polymers. These composites are useful because of the low mechanical moduli of hydrogels. Finally, the potential for thermosetting and photo-cross-linked hydrogels as three-dimensionally (3D) printed, patient-specific devices is highlighted. Three-dimensional printing enables controlled spatial distribution of scaffold materials, cells, and growth factors. Hydrogels, especially natural hydrogels present in bone matrix, have great potential to augment existing bone tissue engineering devices for the treatment of critical size bone defects. PMID:26693013
Stulberg, S David
The treatment of small bone defects in revision total knee arthroplasty should make immediate full weight bearing and full therapy possible, provide long-term stability for the implants, and restore bone stock. These objectives are achieved with bone grafts if the defects are cavitary or small (involving less than one fourth of the cortical rim) segmental defects. These objectives are achieved with porous metal augments if the defects are segmental and involve more than one fourth of the cortical rim. The treatment of bone loss on the femur must allow the re-establishment of the distal and posterior joint lines as well as provide a firm fixation base for the implants.
Tests and Procedures Bone density test By Mayo Clinic Staff A bone density test determines if you have osteoporosis — a disease that causes bones to ... your bones could be quite weak. A bone density test enhances the accuracy of calculating your risk ...
... All Site Content AOFAS / FootCareMD / Treatments Proximal Tibial Bone Graft Page Content What is a bone graft? Bone grafts may be needed for various ... the proximal tibia. What is a proximal tibial bone graft? Proximal tibial bone graft (PTBG) is a ...
Abdelrazek, Saeid; Szumowski, Piotr; Rogowski, Franciszek; Kociura-Sawicka, Agnieszka; Mojsak, Małgorzata; Szorc, Małgorzata
Metabolic bone disease encompasses a number of disorders that tend to present a generalized involvement of the whole skeleton. The disorders are mostly related to increased bone turnover and increased uptake of radiolabelled diphosphonate. Skeletal uptake of 99mTc-labelled diphosphonate depends primarily upon osteoblastic activity, and to a lesser extent, skeletal vascularity. A bone scan image therefore presents a functional display of total skeletal metabolism and has valuable role to play in the assessment of patients with metabolic bone disorders. However, the bone scan appearances in metabolic bone disease are often non-specific, and their recognition depends on increased tracer uptake throughout the whole skeleton. It is the presence of local lesions, as in metastatic disease, that makes a bone scan appearance obviously abnormal. In the early stages, there will be difficulty in evaluating the bone scans from many patients with metabolic bone disease. However, in the more severe cases scan appearances can be quite striking and virtually diagnostic.
McKillop, J.H.; Maharaj, D.; Boyce, B.F.; Fogelman, I.
Bone marrow and bone biopsies are performed not infrequently in patients referred for bone scans and represent a potential cause of a ''false positive'' focal abnormality on the bone scan. The authors have therefore examined the scan appearances in a series of patients who had undergone either sternal marrow biopsy, (Salah needle, diameter 1.2 mm) trephine iliac crest marrow biopsy (Jamshidi 11 gauge needle, diameter 3.5 mm) or a transiliac bone biopsy (needle diameter 8 mm). Of 18 patients studied 1 to 45 days after sternal marrow 17 had normal scan appearances at the biopsy site and 1 had a possible abnormality. None of 9 patients studied 4 to 19 days after trephine iliac crest marrow biopsy had a hot spot at the biopsy site. A focal scan abnormality was present at the biopsy site in 9/11 patients studied 5 to 59 days after a trans iliac bone biopsy. No resultant scan abnormality was seen in 4 patients imaged within 3 days of the bone biopsy or in 3 patients imaged 79 to 138 days after the procedure. Bone marrow biopsy of the sternum or iliac crest does not usually cause bone scan abnormalities. A focal abnormality at the biopsy site is common in patients imaged 5 days to 2 months after bone biopsy. The gauge of the needle employed in the biopsy and thus the degree of bone trauma inflicted, is likely to be main factor determining the appearance of bone scan abnormalities at the biopsy site.
Berendsen, Agnes D.; Olsen, Bjorn R.
The development of the vertebrate skeleton reflects its evolutionary history. Cartilage formation came before biomineralization and a head skeleton evolved before the formation of axial and appendicular skeletal structures. This review describes the processes that result in endochondral and intramembranous ossification, the important roles of growth and transcription factors, and the consequences of mutations in some of the genes involved. Following a summary of the origin of cartilage, muscle, and tendon cell lineages in the axial skeleton, we discuss the role of muscle forces in the formation of skeletal architecture and assembly of musculoskeletal functional units. Finally, ontogenetic patterning of bones in response to mechanical loading is reviewed. PMID:26453494
Jankowski, J; Mikulski, D; Tatara, M R; Krupski, W
Effects of increased stocking density and heat stress on growth, feed conversion, carcase characteristics and skeletal system properties in turkeys were determined. One-day-old males (n=1674) were divided into two weight-matched groups exposed to different environmental conditions. Controls were reared at a stocking density of 2.8 birds/m(2) and at thermo-neutral temperature (TnT group), while the experimental group was exposed to heat-stress (HSID group) and reared at a stocking density of 3.4 birds/m(2) and ambient temperature increased by 5°C. At 28 days of age, 27 birds from each group were sacrificed, while at 126 days of age, 54 birds from each group were slaughtered. Increased stocking density and ambient temperature during the first four weeks of life increased the body weight (BW) of turkeys and weight, length, volume, vertical internal and horizontal external diameters of the tibia in the HSID group compared with the TnT group (P<0.05). In turkeys older than four weeks, increased stocking density and ambient temperature significantly decreased daily feed intake, final BW and relative weight of drumstick muscle by 4.7 per cent, 4.0 per cent and 3.3 per cent, respectively (P<0.05). The weight, length, volume, vertical and horizontal diameters, cross-sectional area, second moment of inertia, volumetric bone mineral density, maximum elastic strength and ultimate strength of bones were significantly lower in turkeys in the HSID group (P<0.05) at 126 days compared with turkeys in the TnT group at the same age. These results indicate that, up to four weeks of age, turkeys tolerate increased stocking density and heat stress better than birds between 5 and 18 weeks of age.
... 12 Banks and Banking 7 2010-01-01 2010-01-01 false Capital stock requirements; unilateral redemption of excess stock. 950.11 Section 950.11 Banks and Banking FEDERAL HOUSING FINANCE BOARD FEDERAL HOME LOAN BANK ASSETS AND OFF-BALANCE SHEET ITEMS ADVANCES Advances to Members § 950.11 Capital...
Letcher, B.H.; King, T.L.
We present an approach to stock identification of small, targeted populations that uses multilocus microsatellite genotypes of individual mating adults to uniquely identify first- and second-generation offspring in a mixture. We call the approach 'familyprinting'; unlike DNA fingerprinting where tissue samples of individuals are matched, offspring from various families are assigned to pairs of parents or sets of four grandparents with known genotypes. The basic unit of identification is the family, but families can be nested within a variety of stock units ranging from naturally reproducing groups of fish in a small tributary or pond from which mating adults can be sampled to large or small collections of families produced in hatcheries and stocked in specific locations. We show that, with as few as seven alleles per locus using four loci without error, first-generation offspring can be uniquely assigned to the correct family. For second-generation applications in a hatchery more alleles per locus (10) and loci (10) are required for correct assignment of all offspring to the correct set of grandparents. Using microsatellite DNA variation from an Atlantic salmon (Salmo solar) restoration river (Connecticut River, USA), we also show that this population contains sufficient genetic diversity in sea-run returns for 100% correct first, generation assignment and 97% correct second-generation assignment using 14 loci. We are currently using first- and second-generation familyprinting in this population with the ultimate goal of identifying stocking tributary. In addition to within-river familyprinting, there also appears to be sufficient genetic diversity within and between Atlantic salmon populations for identification of 'familyprinted' fish in a mixture of multiple populations. We also suggest that second-generation familyprinting with multiple populations may also provide a tool for examining stock structure. Familyprinting with microsatellite DNA markers is a viable
Chang, Chong Bum; Yoo, Jeong Joon; Song, Won Seok; Kim, Deug Joong; Koo, Kyung-Hoi; Kim, Hee Joong
We aimed to investigate the transfer of metal to both ceramic (alumina) and metal (cobalt-chrome) heads that were scraped by a titanium alloy surface under different load conditions. The ceramic and metal heads for total hip arthroplasties were scraped by an acetabular metal shell under various loads using a creep tester. Microstructural changes in the scraped area were visualized with a scanning electron microscope, and chemical element changes were assessed using an energy dispersive X-ray spectrometry. Changes in the roughness of the scraped surface were evaluated by a three-dimensional surface profiling system. Metal transfer to the ceramic and metal heads began to be detectable at a 10 kg load, which could be exerted by one-handed force. The surface roughness values significantly increased with increasing test loads in both heads. When the contact force increased, scratching of the head surface occurred in addition to the transfer of metal. The results documented that metallic debris was transferred from the titanium alloy acetabular shell to both ceramic and metal heads by minor scraping. This study suggests that the greatest possible effort should be made to protect femoral heads, regardless of material, from contact with metallic surfaces during total hip arthroplasty.
... You reach your highest bone mass (size and density) at about age 30. Then, sometime between age ... your bones, your doctor may do a bone density test (DEXA scan). This test gives exact measurements ...
... bone the higher the risk of fractures. A bone scan, along with a patient's medical history, is a ... and whether any preventative treatment is needed. A bone density scan has the advantage of being painless and exposing ...
Huang, Tsang-hai; Ables, Gene P
Caloric restriction (CR), protein restriction (PR), and specific amino acid restriction (e.g., methionine restriction (MR)) are different dietary interventions that have been confirmed with regard to their comprehensive benefits to metabolism and health. Based on bone densitometric measurements, weight loss induced by dietary restriction is known to be accompanied by reduced areal bone mineral density, bone mass, and/or bone size, and it is considered harmful to bone health. However, because of technological advancements in bone densitometric instruments (e.g., high-resolution X-ray tomography), dietary restrictions have been found to cause a reduction in bone mass/size rather than volumetric bone mineral density. Furthermore, when considering bone quality, bone health consists of diverse indices that cannot be fully represented by densitometric measurements alone. Indeed, there is evidence that moderate dietary restrictions do not impair intrinsic bone material properties, despite the reduction in whole-bone strength because of a smaller bone size. In the present review, we integrate research evidence from traditional densitometric measurements, metabolic status assays (e.g., energy metabolism, oxidative stresses, and inflammatory responses), and biomaterial analyses to provide revised conclusions regarding the effects of CR, PR, and MR on the skeleton.
Langlois, J; Atlan, F; Scemama, C; Courpied, J P; Hamadouche, M
Most published randomised controlled trials which compare the rates of wear of conventional and cross-linked (XL) polyethylene (PE) in total hip arthroplasty (THA) have described their use with a cementless acetabular component. We conducted a prospective randomised study to assess the rates of penetration of two distinct types of PE in otherwise identical cemented all-PE acetabular components. A total of 100 consecutive patients for THA were randomised to receive an acetabular component which had been either highly XL then remelted or moderately XL then annealed. After a minimum of eight years follow-up, 38 hips in the XL group and 30 hips in the annealed group had complete data (mean follow-up of 9.1 years (7.6 to 10.7) and 8.7 years (7.2 to 10.2), respectively). In the XL group, the steady state rate of penetration from one year onwards was -0.0002 mm/year (sd 0.108): in the annealed group it was 0.1382 mm/year (sd 0.129) (Mann-Whitney U test, p < 0.001). No complication specific to either material was recorded. These results show that the yearly linear rate of femoral head penetration can be significantly reduced by using a highly XLPE cemented acetabular component.
Huen, Tan Bee; Arsad, Zainudin; Chun, Ooi Po
Realizing the greater risk by the increase in the level of financial market integration, this study investigates the dynamic of international and regional stock markets co-movement among Asian countries with the world leading market, the US. The data utilized in this study comprises of weekly closing prices for four stock indices, that consists of two developing markets (Malaysia and China) and two developed markets (Japan and the US), and encompasses the period from January 1996 to December 2012. Multivariate Generalized Autoregressive Conditional Heteroscedasticity (MGARCH) model with the BEKK parameterization is employed to investigate the mean and volatility spillover effects among the selected stock indices. The results show significant mean spillover not only from the larger developed markets to smaller developing markets but also from the smaller developing markets to larger developed markets. Volatility spillover between the developed markets is found to be smaller than that between the developing markets. Conditional correlations among the stock markets are found to increase over the sample period. The findings of significant mean and volatility spillovers are considered as bad news for international investors as it reduces the benefit from portfolio diversification but act as useful information for investors to be more aware in diversifying their investment or stock selection.
White, Ainslie; Lee, Youngki; Ivanov, Plamen Ch.
We study intertrades times (ITT) of stock trades of a range of companies included in the New York Stock Exchange's Trades and Quotes (TAQ) database. The time between transactions is an indicator of the dynamics of the market, and in the field of econometrics, intertrade durations play a key role in the understanding of the market activity and microstructure. Previous work has mainly focused on the properties of price changes of individual company stocks as well as global financial indices (e.g. SP500, DJ etc.). We hypothesize that there is a relation between the dynamics of price change and the trading activity. To investigate this relation we first study the statistical features of ITT data. The TAQ database covers all transactions on the NSE, AMEX, NASDAQ and the US regional exchanges. We have performed a preliminary analysis of 100 company stocks from a range of industries of the US economy selecting predominantly those companies which have large market capitalisations (MC). We focus on companies with large MC, since the dynamics of the price change and trading activity of stocks of such companies has a considerable impact on the market behaviour.
Schill, W.B.; Dorazio, R.M.
Stocks of Atlantic striped bass Morone saxatilis that were assumed to be geographically isolated during spawning showed strong antigenic differences in blood serum albumin. A discriminant function was estimated from the immunologic responses of northern (Canadian and Hudson River) and southern (Chesapeake Bay and Roanoke River) stocks to two reference antisera. The function correctly classified 92% of the northern and 95% of the southern fish in the training set. Cross-validation revealed similar percentages of correct classification for fish that were of known origin but not used to estimate the discriminant function. Monte Carlo experiments were used to evaluate the ability of the discriminant function to predict the relative contribution of northern fish in samples of various size and stock composition. Averages of predicted proportions of northern fish in the samples agreed well with actual proportions. Coefficients of variation (100 × SD/mean) in the predicted proportions ranged from 1.5 to 36% for samples of 50–400 fish that contained at least 10% northern stock. In samples that contained only 2% northern stock, however, at least 1,600 fish were required to achieve similar levels of precision.
Britten, Gregory L; Dowd, Michael; Worm, Boris
Marine fish and invertebrates are shifting their regional and global distributions in response to climate change, but it is unclear whether their productivity is being affected as well. Here we tested for time-varying trends in biological productivity parameters across 262 fish stocks of 127 species in 39 large marine ecosystems and high-seas areas (hereafter LMEs). This global meta-analysis revealed widespread changes in the relationship between spawning stock size and the production of juvenile offspring (recruitment), suggesting fundamental biological change in fish stock productivity at early life stages. Across regions, we estimate that average recruitment capacity has declined at a rate approximately equal to 3% of the historical maximum per decade. However, we observed large variability among stocks and regions; for example, highly negative trends in the North Atlantic contrast with more neutral patterns in the North Pacific. The extent of biological change in each LME was significantly related to observed changes in phytoplankton chlorophyll concentration and the intensity of historical overfishing in that ecosystem. We conclude that both environmental changes and chronic overfishing have already affected the productive capacity of many stocks at the recruitment stage of the life cycle. These results provide a baseline for ecosystem-based fisheries management and may help adjust expectations for future food production from the oceans.
Gao, Ya-Chun; Zeng, Yong; Cai, Shi-Min
In a stock market, the price fluctuations are interactive, that is, one listed company can influence others. In this paper, we seek to study the influence relationships among listed companies by constructing a directed network on the basis of the Chinese stock market. This influence network shows distinct topological properties. In particular, a few large companies that can lead the tendency of the stock market are recognized. Furthermore, by analyzing the subnetworks of listed companies distributed in several significant economic sectors, it is found that the influence relationships are totally different from one economic sector to another, of which three types of connectivity as well as hub-like listed companies are identified. In addition, the rankings of listed companies obtained from the centrality metrics of the influence network are compared with those according to the assets, which gives inspiration to uncover and understand the importance of listed companies on the stock market. These empirical results are meaningful in providing these topological properties of the Chinese stock market and economic sectors as well as revealing the interactive influence relationships among listed companies.
Silva, A. Christian; Neto, Camilo; Crepaldi, Antonio; Ferreira, Fernando
We apply several multi-resolution analysis to filter the stock market time series. We use wavelet based techniques and the Empirical mode decomposition technique. Here, filtering financial series, removes high frequency components and lead to a smooth or a more deterministic time series. When working with wavelets, we use a neural network to select the resolution level to get the maximum prediction. This approach helps to increase the predictive performance of the deterministic and statistical tools. Then we study the frequencies by computing the spectrogram for the average of 328 stocks. We find that similar patterns are detected when using Empirical mode decomposition technique. We also study the correlation in the time-frequency space among all set of stocks. This is done by computing the cross wavelet and EMD transform of the standardized time series. The statistical significance level of all the measures used in the preset paper was carried out by comparing the empirical results with a surrogate and random data, with critical values fixed at 5% significance level. These results may be helpful to investigate how the stocks are clustered and to determine a subset of synchronized stocks in this region.
Britten, Gregory L.; Dowd, Michael; Worm, Boris
Marine fish and invertebrates are shifting their regional and global distributions in response to climate change, but it is unclear whether their productivity is being affected as well. Here we tested for time-varying trends in biological productivity parameters across 262 fish stocks of 127 species in 39 large marine ecosystems and high-seas areas (hereafter LMEs). This global meta-analysis revealed widespread changes in the relationship between spawning stock size and the production of juvenile offspring (recruitment), suggesting fundamental biological change in fish stock productivity at early life stages. Across regions, we estimate that average recruitment capacity has declined at a rate approximately equal to 3% of the historical maximum per decade. However, we observed large variability among stocks and regions; for example, highly negative trends in the North Atlantic contrast with more neutral patterns in the North Pacific. The extent of biological change in each LME was significantly related to observed changes in phytoplankton chlorophyll concentration and the intensity of historical overfishing in that ecosystem. We conclude that both environmental changes and chronic overfishing have already affected the productive capacity of many stocks at the recruitment stage of the life cycle. These results provide a baseline for ecosystem-based fisheries management and may help adjust expectations for future food production from the oceans. PMID:26668368
Transplant - bone marrow - discharge; Stem cell transplant - discharge; Hematopoietic stem cell transplant - discharge; Reduced intensity; Non-myeloablative transplant - discharge; Mini transplant - discharge; Allogenic bone marrow transplant - ...
Sun, Xiaoqian; Cheng, Xueqi; Shen, Huawei; Wang, Zhaoyang
We investigate the statistical properties of traders' trading behavior using cumulative distribution function(CDF). We analyze exchange data of 52 stocks for one-year period which contains non-manipulated stocks and manipulated stocks published by China Securities Regulatory Commission(CSRC). By analyzing the total number of transactions and the trading volume of each trader over a year, we find the cumulative distributions have power-law tails and the distributions between non-manipulated stocks and manipulated stocks are different. These findings can help us to detect the manipulated stocks.
Geometric phases describe how in a continuous-time dynamical system the displacement of a variable (called phase variable) can be related to other variables (shape variables) undergoing a cyclic motion, according to an area rule. The aim of this paper is to show that geometric phases can exist also for discrete-time systems, and even when the cycles in shape space have zero area. A context in which this principle can be applied is stock trading. A zero-area cycle in shape space represents the type of trading operations normally carried out by high-frequency traders (entering and exiting a position on a fast time-scale), while the phase variable represents the cash balance of a trader. Under the assumption that trading impacts stock prices, even zero-area cyclic trading operations can induce geometric phases, i.e., profits or losses, without affecting the stock quote. PMID:27556642
Jung, Sean S.; Chang, Woojin
A partial correlation analysis is performed on the Korean stock market (KOSPI). The difference between Pearson correlation and the partial correlation is analyzed and it is found that when conditioned on the market return, Pearson correlation coefficients are generally greater than those of the partial correlation, which implies that the market return tends to drive up the correlation between stock returns. A clustering analysis is then performed to study the market structure given by the partial correlation analysis and the members of the clusters are compared with the Global Industry Classification Standard (GICS). The initial hypothesis is that the firms in the same GICS sector are clustered together since they are in a similar business and environment. However, the result is inconsistent with the hypothesis and most clusters are a mix of multiple sectors suggesting that the traditional approach of using sectors to determine the proximity between stocks may not be sufficient enough to diversify a portfolio.
Cheng, Wuyang; Wang, Jun
A random financial stock price model is developed by the interacting contact process, which is one of the statistical-physics systems. The contact process is a continuous-time Markov process, one interpretation of this process is as a model for the spread of an infection, where the epidemic spreading mimics the interplay of local infections and the recovery of individuals. We investigate and analyze the long-term memory, the nonlinear correlations and the multifractal phenomenon of normalized returns of the price model by statistical analysis methods, which include autocorrelation analysis, the Gaussian copula method and the multifractal analysis method. Moreover, we consider the daily returns of the Shanghai Stock Exchange Composite Index and the Shenzhen Stock Exchange Composite Index, and the comparisons of statistical behaviors of returns between the actual data and the simulation data are presented.
Ataullah, Ali; Davidson, Ian; Tippett, Mark
The instantaneous return on the Financial Times-Stock Exchange (FTSE) All Share Index is viewed as a frictionless particle moving in a one-dimensional square well but where there is a non-trivial probability of the particle tunneling into the well’s retaining walls. Our analysis demonstrates how the complementarity principle from quantum mechanics applies to stock market prices and of how the wave function presented by it leads to a probability density which exhibits strong compatibility with returns earned on the FTSE All Share Index. In particular, our analysis shows that the probability density for stock market returns is highly leptokurtic with slight (though not significant) negative skewness. Moreover, the moments of the probability density determined under the complementarity principle employed here are all convergent - in contrast to many of the probability density functions on which the received theory of finance is based.
Botta, Federico; Moat, Helen Susannah; Stanley, H. Eugene; Preis, Tobias
Being able to quantify the probability of large price changes in stock markets is of crucial importance in understanding financial crises that affect the lives of people worldwide. Large changes in stock market prices can arise abruptly, within a matter of minutes, or develop across much longer time scales. Here, we analyze a dataset comprising the stocks forming the Dow Jones Industrial Average at a second by second resolution in the period from January 2008 to July 2010 in order to quantify the distribution of changes in market prices at a range of time scales. We find that the tails of the distributions of logarithmic price changes, or returns, exhibit power law decays for time scales ranging from 300 seconds to 3600 seconds. For larger time scales, we find that the distributions tails exhibit exponential decay. Our findings may inform the development of models of market behavior across varying time scales. PMID:26327593
Gkiatas, Ioannis; Lykissas, Marios; Kostas-Agnantis, Ioannis; Korompilias, Anastasios; Batistatou, Anna; Beris, Alexandros
Bone growth and development are products of the complex interactions of genetic and environmental factors. Longitudinal bone growth depends on the growth plate. The growth plate has 5 different zones-each with a different functional role-and is the final target organ for longitudinal growth. Bone length is affected by several systemic, local, and mechanical factors. All these regulation systems control the final length of bones in a complicated way. Despite its significance to bone stability, bone growth in width has not been studied as extensively as longitudinal bone growth. Bone growth in width is also controlled by genetic factors, but mechanical loading regulates periosteal apposition. In this article, we review the most recent data regarding bone growth from the embryonic age and analyze the factors that control bone growth. An understanding of this complex system is important in identifying metabolic and developmental bone diseases and fracture risk.
Jiang, J.; Li, W.; Cai, X.; Wang, Qiuping A.
We investigate the statistical properties of the empirical data taken from the Chinese stock market during the time period from January, 2006 to July, 2007. By using the methods of detrended fluctuation analysis (DFA) and calculating correlation coefficients, we acquire the evidence of strong correlations among different stock types, stock index, stock volume turnover, A share (B share) seat number, and GDP per capita. In addition, we study the behavior of “volatility”, which is now defined as the difference between the new account numbers for two consecutive days. It is shown that the empirical power-law of the number of aftershock events exceeding the selected threshold is analogous to the Omori law originally observed in geophysics. Furthermore, we find that the cumulative distributions of stock return, trade volume and trade number are all exponential-like, which does not belong to the universality class of such distributions found by Xavier Gabaix et al. [Xavier Gabaix, Parameswaran Gopikrishnan, Vasiliki Plerou, H. Eugene Stanley, Nature, 423 (2003)] for major western markets. Through the comparison, we draw a conclusion that regardless of developed stock markets or emerging ones, “cubic law of returns” is valid only in the long-term absolute return, and in the short-term one, the distributions are exponential-like. Specifically, the distributions of both trade volume and trade number display distinct decaying behaviors in two separate regimes. Lastly, the scaling behavior of the relation is analyzed between dispersion and the mean monthly trade value for each administrative area in China.
Bourgeois, Lelania; Sheppard, Walter S; Sylvester, H Allen; Rinderer, Thomas E
A genetic stock certification assay was developed to distinguish Russian honey bees from other European (Apis mellifera L.) stocks that are commercially produced in the United States. In total, 11 microsatellite and five single-nucleotide polymorphism loci were used. Loci were selected for relatively high levels of homogeneity within each group and for differences in allele frequencies between groups. A baseline sample consisted of the 18 lines of Russian honey bees released to the Russian Bee Breeders Association and bees from 34 queen breeders representing commercially produced European honey bee stocks. Suitability tests of the baseline sample pool showed high levels of accuracy. The probability of correct assignment was 94.2% for non-Russian bees and 93.3% for Russian bees. A neighbor-joining phenogram representing genetic distance data showed clear distinction of Russian and non-Russian honey bee stocks. Furthermore, a test of appropriate sample size showed a sample of eight bees per colony maximizes accuracy and consistency of the results. An additional 34 samples were tested as blind samples (origin unknown to those collecting data) to determine accuracy of individual assignment tests. Only one of these samples was incorrectly assigned. The 18 current breeding lines were represented among the 2009 blind sampling, demonstrating temporal stability of the genetic stock identification assay. The certification assay will be used through services provided by a service laboratory, by the Russian Bee Breeders Association to genetically certify their stock. The genetic certification will be used in conjunction with continued selection for favorable traits, such as honey production and varroa and tracheal mite resistance.
Sun, Xiao-Qian; Shen, Hua-Wei; Cheng, Xue-Qi; Zhang, Yuqing
Stock price prediction is an important and challenging problem in stock market analysis. Existing prediction methods either exploit autocorrelation of stock price and its correlation with the supply and demand of stock, or explore predictive indictors exogenous to stock market. In this paper, using transaction record of stocks with identifier of traders, we introduce an index to characterize market confidence, i.e., the ratio of the number of traders who is active in two successive trading days to the number of active traders in a certain trading day. Strong Granger causality is found between the index of market confidence and stock price. We further predict stock price by incorporating the index of market confidence into a neural network based on time series of stock price. Experimental results on 50 stocks in two Chinese Stock Exchanges demonstrate that the accuracy of stock price prediction is significantly improved by the inclusion of the market confidence index. This study sheds light on using cross-day trading behavior to characterize market confidence and to predict stock price.
Sun, Xiao-Qian; Shen, Hua-Wei; Cheng, Xue-Qi; Zhang, Yuqing
Stock price prediction is an important and challenging problem in stock market analysis. Existing prediction methods either exploit autocorrelation of stock price and its correlation with the supply and demand of stock, or explore predictive indictors exogenous to stock market. In this paper, using transaction record of stocks with identifier of traders, we introduce an index to characterize market confidence, i.e., the ratio of the number of traders who is active in two successive trading days to the number of active traders in a certain trading day. Strong Granger causality is found between the index of market confidence and stock price. We further predict stock price by incorporating the index of market confidence into a neural network based on time series of stock price. Experimental results on 50 stocks in two Chinese Stock Exchanges demonstrate that the accuracy of stock price prediction is significantly improved by the inclusion of the market confidence index. This study sheds light on using cross-day trading behavior to characterize market confidence and to predict stock price. PMID:27391816
Gorbics, C.S.; Bodkin, J.L.
Sea otters in Alaska are recognized as a single subspecies (Enhydra lutris kenyoni) and currently managed as a single, interbreeding population. However, geographic and behavioral mechanisms undoubtably constrain sea otter movements on much smaller scales. This paper applies the phylogeographic method (Dizon et al. 1992) and considers distribution, population response, phenotype and genotype data to identify stocks of sea otters within Alaska. The evidence for separate stock identity is genotypic (all stocks), phenotypic (Southcentral and Southwest stocks), and geographic distribution (Southeast stock), whereas population response data are equivocal (all stocks). Differences in genotype frequencies and the presence of unique genotypes among areas indicate restricted gene flow. Genetic exchange may be limited by little or no movement across proposed stock boundaries and discontinuities in distribution at proposed stock boundaries. Skull size differences (phenotypic) between Southwest and Southcentral Alaska populations further support stock separation. Population response information was equivocal in either supporting or refuting stock identity. On the basis of this review, we suggest the following: (1) a Southeast stock extending from Dixon Entrance to Cape Yakataga; (2) a Southcentral stock extending from Cape Yakataga to Cape Douglas including Prince William Sound and Kenai peninsula coast; and (3) a Southwest stock including Alaska Peninsula coast, the Aleutians to Attu Island, Barren, Kodiak, Pribilof Islands, and Bristol Bay.
Jiang, Zhi-Qiang; Zhou, Wei-Xing
Multifractal analysis and extensive statistical tests are performed upon intraday minutely data within individual trading days for four stock market indexes (including HSI, SZSC, S&P 500, and NASDAQ) to check whether the indexes (instead of the returns) possess multifractality. We find that the mass exponent τ(q) is linear and the singularity α(q) is close to 1 for all trading days and all indexes. Furthermore, we find strong evidence showing that the scaling behaviors of the original data sets cannot be distinguished from those of shuffled time series. Hence, the so-called multifractality in the intraday stock market indexes is merely an illusion.
Ting, Julian Juhi-Lian
Volatility, fitting with first-order Landau expansion, stationarity, and causality of the Taiwan stock market (TAIEX) are investigated based on daily records. Instead of consensuses that consider stock market index change as a random time series we propose the market change as a dual time series consists of the index and the corresponding volume. Therefore, causalities between these two time series are investigated. Our results suggest the volume time series is of second-order importance than the index time series. The index time series receives slightly stronger influence from the previous 67th trading day, while the volume time series is slightly stronger influenced by the previous 62nd trading day.
Komo, Darmadi; Chang, Chein-I.; Ko, Hanseok
A neural network approach to stock market index prediction is presented. Actual data of the Wall Street Journal's Dow Jones Industrial Index has been used for a benchmark in our experiments where Radial Basis Function based neural networks have been designed to model these indices over the period from January 1988 to Dec 1992. A notable success has been achieved with the proposed model producing over 90% prediction accuracies observed based on monthly Dow Jones Industrial Index predictions. The model has also captured both moderate and heavy index fluctuations. The experiments conducted in this study demonstrated that the Radial Basis Function neural network represents an excellent candidate to predict stock market index.
McKillop, J.H.; Maharaj, D.; Boyce, B.F.; Fogelman, I.
The influence of sternal marrow aspiration, iliac crest marrow aspiration, and iliac crest bone biopsy on bone scan appearances was examined. Eighteen patients were scanned a mean of 9.9 days after sternal marrow aspiration with a Salah needle. Bone scans obtained in 9 patients a mean of 10 days aftr iliac crest trephine marrow biopsy with a Jamshidi needle showed no abnormality at the biopsy site. In 18 patients with metabolic bone disease who had undergone iliac crest bone biopsy with an 8 mm needle, a scan abnormality due to the biopsy was usually present when the interval between the biopsy and the scan was 5 days to 2 months. Patients who were scanned within 3 days of iliac crest bone biopsy or more than 2 months after biopsy had normal scan appearance at the biopsy site.
Peterson, R. M.
Calibration technique detects minute laminar-type discontinuities in thin metal strip stock. Patterns of plastic tape are preselected to include minutely calculated discontinuities and the tape is applied to the strip stock to intercept the incident sonic beam.
... CIGARETTE PAPERS AND TUBES Floor Stocks Tax on Certain Tobacco Products, Cigarette Papers, and Cigarette....28T09, 2009 Floor Stocks Tax Return—Tobacco Products and Cigarette Papers and Tubes, is available...
... CIGARETTE PAPERS AND TUBES Floor Stocks Tax on Certain Tobacco Products, Cigarette Papers, and Cigarette....28T09, 2009 Floor Stocks Tax Return—Tobacco Products and Cigarette Papers and Tubes, is available...
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... CIGARETTE PAPERS AND TUBES Floor Stocks Tax on Certain Tobacco Products, Cigarette Papers, and Cigarette....28T09, 2009 Floor Stocks Tax Return—Tobacco Products and Cigarette Papers and Tubes, is available...
Kagan, Gary; And Others
Maintains that stock market games are designed to provide students with a background for investing in securities, especially stocks. Reviews two games used with secondary students, analyzes statistical data from these experiences, and considers weaknesses in the games. (CFR)
Bone marrow is the spongy tissue inside some of your bones, such as your hip and thigh bones. It contains stem cells. The stem cells can ... the platelets that help with blood clotting. With bone marrow disease, there are problems with the stem ...
... secrete factors that interact with the naturally occurring cells in the bone and cause bone destruction, new bone formation, or both. Eﬀects Because MBD weakens the aﬀected bones, people with the disease are prone to fractures. Broken ...
Shang, Zhe; Wang, Lei; Wu, Han
The present research examined the influence of perceived ownership (self/other) and perceived chooser (self/other) of stocks on brain activity, and investigated whether differential brain responses to stock outcomes as a result of perceived differences in ownership of stock would be modulated by perceived chooser of stock. We used a 2 (stock chooser: self, other) × 2 (stock owner: self, other) within-subject design to represent four types of chooser-owner relationships. Brain potentials were recorded while participants observed increasing and decreasing stock prices. Results showed that observations of stock outcomes among four types of chooser-owner relationships elicited differentiated feedback-related negativity (d-FRN: differences in FRN waves between losses and gains, reflecting violations of expectancy to stock outcomes): (1) Self-chosen-other-owned stocks evoked significantly larger d-FRN discrepancies than self-chosen-self-owned stocks, indicating a greater expectancy violation to others' losses than to one's own, demonstrating a reversed ownership effect. Moreover, people high in conscientiousness showed an increase in this trend, suggesting a stronger other-consideration; (2) Self-chosen-self-owned stocks and other-chosen-self-owned stocks revealed no significant d-FRN discrepancy, showing no choosership effect beyond the ownership effect; (3) Other-chosen-self-owned stocks evoked a significantly stronger d-FRN discrepancy than other-chosen-other-owned stocks, demonstrating an ownership effect; (4) Self-chosen-other-owned stocks evoked a significantly stronger d-FRN discrepancy than other-chosen-other-owned stocks, revealing a choosership effect. These findings suggest that the ownership effect could be reversed by conscientiousness induced by perceived choosership in the agency relationship, while the choosership effect is attenuated and even disappears under the influence of perceived ownership.
Shang, Zhe; Wang, Lei; Wu, Han
The present research examined the influence of perceived ownership (self/other) and perceived chooser (self/other) of stocks on brain activity, and investigated whether differential brain responses to stock outcomes as a result of perceived differences in ownership of stock would be modulated by perceived chooser of stock. We used a 2 (stock chooser: self, other) × 2 (stock owner: self, other) within-subject design to represent four types of chooser-owner relationships. Brain potentials were recorded while participants observed increasing and decreasing stock prices. Results showed that observations of stock outcomes among four types of chooser-owner relationships elicited differentiated feedback-related negativity (d-FRN: differences in FRN waves between losses and gains, reflecting violations of expectancy to stock outcomes): (1) Self-chosen-other-owned stocks evoked significantly larger d-FRN discrepancies than self-chosen-self-owned stocks, indicating a greater expectancy violation to others' losses than to one's own, demonstrating a reversed ownership effect. Moreover, people high in conscientiousness showed an increase in this trend, suggesting a stronger other-consideration; (2) Self-chosen-self-owned stocks and other-chosen-self-owned stocks revealed no significant d-FRN discrepancy, showing no choosership effect beyond the ownership effect; (3) Other-chosen-self-owned stocks evoked a significantly stronger d-FRN discrepancy than other-chosen-other-owned stocks, demonstrating an ownership effect; (4) Self-chosen-other-owned stocks evoked a significantly stronger d-FRN discrepancy than other-chosen-other-owned stocks, revealing a choosership effect. These findings suggest that the ownership effect could be reversed by conscientiousness induced by perceived choosership in the agency relationship, while the choosership effect is attenuated and even disappears under the influence of perceived ownership. PMID:28194118
Hara, Daisuke; Nakashima, Yasuharu; Sato, Taishi; Hirata, Masanobu; Kanazawa, Masayuki; Kohno, Yusuke; Yoshimoto, Kensei; Yoshihara, Yusuke; Nakamura, Akihiro; Nakao, Yumiko; Iwamoto, Yukihide
The present study examined the bone bonding strength of diamond-structured porous titanium-alloy (Porous-Ti-alloy) manufactured using the electron beam-melting technique in comparison with fiber mesh-coated or rough-surfaced implants. Cylindrical implants with four different pore sizes (500, 640, 800, and 1000μm) of Porous-Ti-alloy, titanium fiber mesh (FM), and surfaces roughened by titanium arc spray (Ti-spray) were implanted into the distal femur of rabbits. Bone bonding strength and histological bone ingrowth were evaluated at 4 and 12weeks after implantation. The bone bonding strength of Porous-Ti-alloy implants (640μm pore size) increased over time from 541.4N at 4weeks to 704.6N at 12weeks and was comparable to that of FM and Ti-spray implants at both weeks. No breakage of the porous structure after mechanical testing was found with Porous-Ti-alloy implants. Histological bone ingrowth that increased with implantation time occurred along the inner structure of Porous-Ti-alloy implants. There was no difference in bone ingrowth in Porous-Ti-alloy implants with pore sizes among 500, 640, and 800μm; however, less bone ingrowth was observed with the 1000μm pore size. These results indicated Porous-Ti-alloy implants with pore size under 800μm provided biologically active and mechanically stable surface for implant fixation to bone, and had potential advantages for weight bearing orthopedic implants such as acetabular cups.