bluuebunny/crossref_metadata_2025 huggingface dataset:
Cost of Liver Transplantation
Authors: van der Hilst Christian S. , IJtsma Alexander J. C. , Slooff Maarten J. H. , TenVergert Elisabeth M.
Published: November 2008

Large cost variations of liver transplantation are reported. The aim of this study was to assess cost differences of liver transplantation and clinical follow-up between the United States and other Organization for Economic Cooperation and Development (OECD) countries. Eight electronic databases were searched, and 2,000 citations published after 1990 with more than 10 transplantations, and with original cost data, were identified. A total of 30 articles included 5,975 liver transplantations. Meta-analysis was used to derive a combined mean using a random-effects model to test for heterogeneity between studies. Estimated mean cost of a U.S. liver transplantation was US$163,438 (US$145,277-181,598) compared to US$103,548 (US$85,514-121,582) for other OECD countries. Patient characteristics, disease characteristics, quality of the health care provider, and methodology could not explain this cost difference. Health system characteristics differed between the U.S. and other OECD countries. Cost differences in liver transplantation between these two groups may be largely explained by health system characteristics.
Waterspirit-Carrying Woman
Authors: Gleason Judith
Published: November 2008

1977. We meet Ngowuka, waterspirit priestess of an indigenous healing tradition, on Bolo Island within Okrikan precincts of the Niger Delta. Further visits over the years entail experiences not easily analyzed. An exception is the process of buruao body painting, on which this essay focuses, eventually mandala-like to remain an evanescent simulacrum of the spirit-saturated natural world of Ngowuka and her congeners. As global oil prices surge and subside, transnational companies and Nigeria's military plutocracy hang on, whereas people living along shores from which the oil is pumped sink into destitution. Conjointly, Nguwuka in her own world falters.
A Kinematic and Electromyographic Analysis of Turning in People With Parkinson Disease
Authors: Hong Minna , Perlmutter Joel S. , Earhart Gammon M.
Published: November 2008

Background. Parkinson disease frequently causes difficulty turning that can lead to falls, loss of independence, and diminished quality of life. Turning in tight spaces, which may be particularly impaired in Parkinson disease, is an essential part of our daily lives, yet a comprehensive analysis of in-place turning has not been published. Objective. This study was conducted to determine whether there are objective differences in turning between people with Parkinson disease and unimpaired people. Methods. In-place turning with kinematics and electromyographic measures was characterized in 11 participants with Parkinson disease and 12 healthy people. Kinematic data were recorded using a 3-dimensional motion capture system in synchrony with electromyographic data from lower extremity muscles as participants turned 180°. Those with Parkinson disease were tested after overnight withdrawal of medication. Results. Both groups used 2 distinct turning strategies. In one, the foot ipsilateral to the turning direction initiated the turn; in the other, the foot contralateral to the turning direction initiated the turn. Kinematic analysis demonstrated a craniocaudal sequence of turning in the unimpaired group, whereas those with Parkinson disease had a simultaneous onset of yaw rotation of the head, trunk, and pelvis. They also took a longer time and more steps to complete turns. Overall, lower extremity muscle activation patterns appeared similar between groups. Conclusion. Differences between the groups were noted for axial control, but lower extremity muscle patterns were similar. This work may provide the foundation for development of new treatments for turning difficulty in Parkinson disease.
Constraint-Induced Therapy Versus Dose-Matched Control Intervention to Improve Motor Ability, Basic/Extended Daily Functions, and Quality of Life in Stroke
Authors: Lin Keh-chung , Wu Ching-yi , Liu Jung-sen , Chen Yueh-tsen , Hsu Chen-jung
Published: November 2008

Background. Trials of constraint-induced movement therapy (CIT) to improve upper extremity function after stroke have usually not included an actively treated control group. Objective. This study compared a modified CIT intervention with a dose-matched control intervention that included restraint of the less affected hand and assessed for differences in motor and functional performance and health-related quality of life. Methods. This 2-group randomized controlled trial, using pretreatment and posttreatment measures, enrolled 32 patients within 6 to 40 months after onset of a first stroke (mean age, 55.7 years). They received either CIT (restraint of the less affected limb combined with intensive training of the affected limb for 2 hours daily 5 days per week for 3 weeks and restraint of the less affected hand for 5 hours outside of the rehabilitation training) or a conventional intervention with hand restraint for the same duration. Outcome measures were the Fugl-Meyer Assessment, Functional Independence Measure, Motor Activity Log, Nottingham Extended Activities of Daily Living Scale, and Stroke Impact Scale. Results. Compared with the control group, the CIT group exhibited significantly better performance in motor function, level of functional independence, mobility of extended activities during daily life, and health-related quality of life after treatment. Conclusions. The robust effects of this form of CIT were demonstrated in various aspects of outcome, including motor function, basic and extended functional ability, and quality of life.
N-Glycans of ADAMTS13 modulate its secretion and von Willebrand factor cleaving activity
Authors: Zhou Wenhua , Tsai Han-Mou
Published: November 2008

Severe deficiency of ADAMTS13, a plasma metalloprotease, leads to thrombotic thrombocytopenic purpura. ADAMTS13 contains 10 putative N-glycosylation sites in or near its metalloprotease sequence, spacer region, thrombospondin type 1 repeat no. 4 (TSR no. 4), and CUB domains. Tunicamycin treatment markedly decreased the secretion of ADAMTS13 into the culture medium of transfected cells. Nevertheless, the protease was efficiently secreted from N-acetylglucosaminyltransferase I–deficient Lec1 Chinese hamster ovary cells, indicating that N-glycosylation in the endoplasmic reticulum, but not the conversion of oligomannose to complex N-glycans in the Golgi complex, is important for secretion. However, ADAMTS13 with oligomannose N-glycans cleaved its substrate, von Willebrand factor (VWF) multimers, less effectively, with a higher Km but similar kcat value. In mutagenesis analysis, decreased secretion and VWF cleaving activity was observed with the N146Q and N828Q mutants, while decreased secretion only was observed with the N552Q mutant of ADAMTS13. Enzymatic removal of N-glycans from ADAMTS13 did not affect its VWF cleaving activity. Thus, N-glycosylation is necessary for efficient secretion of ADAMTS13, while conversion of the N-glycans from oligomannose to complex type in the Golgi complex enhances the proteolytic activity of the protease toward VWF multimers. After its secretion, ADAMTS13 does not require N-glycans for its VWF cleaving activity.
Evolution of GHF5 endoglucanase gene structure in plant-parasitic nematodes: no evidence for an early domain shuffling event
Authors: Kyndt Tina , Haegeman Annelies , Gheysen Godelieve
Published: November 2008

Background

Endo-1,4-beta-glucanases or cellulases from the glycosyl hydrolase family 5 (GHF5) have been found in numerous bacteria and fungi, and recently also in higher eukaryotes, particularly in plant-parasitic nematodes (PPN). The origin of these genes has been attributed to horizontal gene transfer from bacteria, although there still is a lot of uncertainty about the origin and structure of the ancestral GHF5 PPN endoglucanase. It is not clear whether this ancestral endoglucanase consisted of the whole gene cassette, containing a catalytic domain and a carbohydrate-binding module (CBM, type 2 in PPN and bacteria) or only of the catalytic domain while the CBM2 was retrieved by domain shuffling later in evolution. Previous studies on the evolution of these genes have focused primarily on data of sedentary nematodes, while in this study, extra data from migratory nematodes were included.

Results

Two new endoglucanases from the migratory nematodes Pratylenchus coffeae and Ditylenchus africanus were included in this study. The latter one is the first gene isolated from a PPN of a different superfamily (Sphaerularioidea); all previously known nematode endoglucanases belong to the superfamily Tylenchoidea (order Rhabditida). Phylogenetic analyses were conducted with the PPN GHF5 endoglucanases and homologous endoglucanases from bacterial and other eukaryotic lineages such as beetles, fungi and plants. No statistical incongruence between the phylogenetic trees deduced from the catalytic domain and the CBM2 was found, which could suggest that both domains have evolved together. Furthermore, based on gene structure data, we inferred a model for the evolution of the GHF5 endoglucanase gene structure in plant-parasitic nematodes. Our data confirm a close relationship between Pratylenchus spp. and the root knot nematodes, while some Radopholus similis endoglucanases are more similar to cyst nematode genes.

Conclusion

We conclude that the ancestral PPN GHF5 endoglucanase gene most probably consisted of the whole gene cassette, i.e. the GHF5 catalytic domain and the CBM2, rather than that it evolved by domain shuffling. Our evolutionary model for the gene structure in PPN GHF5 endoglucanases implies the occurrence of an early duplication event, and more recent gene duplications at genus or species level.
Mechanisms for human genomic rearrangements
Authors: Gu Wenli , Zhang Feng , Lupski James R
Published: November 2008

Genomic rearrangements describe gross DNA changes of the size ranging from a couple of hundred base pairs, the size of an average exon, to megabases (Mb). When greater than 3 to 5 Mb, such changes are usually visible microscopically by chromosome studies. Human diseases that result from genomic rearrangements have been called genomic disorders. Three major mechanisms have been proposed for genomic rearrangements in the human genome. Non-allelic homologous recombination (NAHR) is mostly mediated by low-copy repeats (LCRs) with recombination hotspots, gene conversion and apparent minimal efficient processing segments. NAHR accounts for most of the recurrent rearrangements: those that share a common size, show clustering of breakpoints, and recur in multiple individuals. Non-recurrent rearrangements are of different sizes in each patient, but may share a smallest region of overlap whose change in copy number may result in shared clinical features among different patients. LCRs do not mediate, but may stimulate non-recurrent events. Some rare NAHRs can also be mediated by highly homologous repetitive sequences (for example, Alu, LINE); these NAHRs account for some of the non-recurrent rearrangements. Other non-recurrent rearrangements can be explained by non-homologous end-joining (NHEJ) and the Fork Stalling and Template Switching (FoSTeS) models. These mechanisms occur both in germ cells, where the rearrangements can be associated with genomic disorders, and in somatic cells in which such genomic rearrangements can cause disorders such as cancer. NAHR, NHEJ and FoSTeS probably account for the majority of genomic rearrangements in our genome and the frequency distribution of the three at a given locus may partially reflect the genomic architecture in proximity to that locus. We provide a review of the current understanding of these three models.
The effect of an intensive care unit staffing model on tidal volume in patients with acute lung injury
Authors: Cooke Colin R , Watkins Timothy R , Kahn Jeremy M , Treggiari Miriam M , Caldwell Ellen , Hudson Leonard D , Rubenfeld Gordon D
Published: November 2008

Introduction

Little is known about the mechanisms through which intensivist physician staffing influences patient outcomes. We aimed to assess the effect of closed-model intensive care on evidence-based ventilatory practice in patients with acute lung injury (ALI).

Methods

We conducted a secondary analysis of a prospective population-based cohort of 759 patients with ALI who were alive and ventilated on day three of ALI, and were cared for in 23 intensive care units (ICUs) in King County, Washington.

Results

We compared day three tidal volume (VT) in open versus closed ICUs adjusting for potential patient and ICU confounders. In 13 closed model ICUs, 429 (63%) patients were cared for. Adjusted mean VT (mL/Kg predicted body weight (PBW) or measured body weight if height not recorded) for patients in closed ICUs was 1.40 mL/Kg PBW (95% confidence interval (CI) = 0.57 to 2.24 mL/Kg PBW) lower than patients in open model ICUs. Patients in closed ICUs were more likely (odds ratio (OR) = 2.23, 95% CI = 1.09 to 4.56) to receive lower VT (≤ 6.5 mL/Kg PBW) and were less likely (OR = 0.30, 95% CI = 0.17 to 0.55) to receive a potentially injurious VT (≥ 12 mL/Kg PBW) compared with patients cared for in open ICUs, independent of other covariates. The effect of closed ICUs on hospital mortality was not changed after accounting for delivered VT.

Conclusions

Patients with ALI cared for in closed model ICUs are more likely to receive lower VT and less likely to receive higher VT, but there were no other differences in measured processes of care. Moreover, the difference in delivered VT did not completely account for the improved mortality observed in closed model ICUs.
Prediction of workpiece surface roughness using soft computing
Authors: Samanta B , Erevelles W , Omurtag Y
Published: November 2008

A study is presented to model surface roughness in end-milling using soft computing (SC) or computational intelligence (CI) techniques. The techniques include the artificial neural network (ANN) and adaptive neuro-fuzzy inference system (ANFIS). ANFIS combines the learning capability of ANN and the effective handling of imprecise information in fuzzy logic. Prediction models based on multivariate regression analysis (MRA) are also presented for comparison. The machining parameters, namely, the spindle speed, feed rate, and depth of cut, were used as inputs to model the workpiece surface roughness. The model parameters were tuned using the training data maximizing the modelling accuracy. The trained models were tested using the set of validation data. The effects of different machining parameters, number, and type of model parameters on the prediction accuracy were studied. The procedure is illustrated using the experimental data of end-milling 6061 aluminium alloy. Although statistically all three models predicted roughness with satisfactory goodness of fit, the test performance of ANFIS was better than ANN and MRA. In comparison with MRA, the performance of ANN was better in training but similar in test. The results show the effectiveness of CI techniques in modelling surface roughness.
Monitoring of slowly progressing deterioration of computer numerical control machine axes
Authors: Uhlmann E , Geisert C , Hohwieler E
Published: November 2008

The feed axes of computer numerical control (CNC) grinding machine tools are among the most mechanically stressed components of machine tools owing to the high process forces and rough manufacturing environment which they encounter. The resulting wear and tear depends strongly on the product range and the manner of machine operation. To counteract a functional deficiency of these central machine units, the current usual approach is preventive maintenance. The manual inspection of feed axes is complex and time consuming. A complicating matter is that the deterioration normally progresses very slowly and depends on the position of the stress along the axis. Existing approaches to automated estimation of the ‘health status’ of feed axes do not take this factor into account.

This paper presents a procedure that addresses this gap. During simple test routines, the drive current, axis position, and feed rate are recorded. With the help of additional machine data, characteristic values are computed directly at the computer of the human—machine interface (HMI). The results are then transferred to and stored on a database server at the machine manufacturer. This approach enables the service technician to trace the progression of the axes’ ‘health status’ over a long time. This approach makes it possible to detect trends in the characteristic values at an early point in time. This leads to a better planning of necessary maintenance actions adapted to the remaining lifetime of the wearing component.
Facilitating ease of system reconfiguration through measures of manufacturing modularity
Authors: Farid A M
Published: November 2008

In recent years, many design approaches have been developed for automated manufacturing systems in the fields of reconfigurable manufacturing systems (RMSs), holonic manufacturing systems (HMSs), and multiagent systems (MASs). One of the principle reasons for these developments has been to enhance the reconfigurability of a manufacturing system, allowing it to adapt readily to changes over time. However, to date reconfigurability assessment has been limited. Hence the efficacy of these design approaches remains inconclusive. This paper is the second of two in this issue to address reconfigurability measurement. Specifically, ‘reconfiguration ease’ has often been qualitatively argued to depend on the system's modularity. For this purpose, this paper develops modularity measures in a three-step approach. Firstly, the nature of typical manufacturing system interfaces is discussed. Next, the qualitative understanding underlying existing modularity measures is distilled. Finally, these understandings are synthesized for a manufacturing system context. This approach forms the second of two pillars that together lay the foundation for an integrated reconfigurability measurement process described elsewhere.
A numerical study of the effect of axial acceleration on the responses of the cervical spine during low-speed rear-end impact
Authors: Zhang Qing Hang , Tan Soon Huat , Teo Ee Chan
Published: November 2008

A detailed, three-dimensional, head—neck (vertebral segments C0 to C7) finite element model — developed and validated previously on the basis of the actual geometry of a cadaveric specimen — was used to evaluate the effect of cranial acceleration on the response of the cervical spine during low-speed, rear-end impact. Analyses were carried out to compare the predicted overall and segmental rotations, peak disc stresses, and capsular ligament strains of each motion segment during whiplash with or without cranial acceleration applied on the C7 inferior surface. The results show that, in the first 150 ms, the variation curves of predicted segmental rotational angles, disc stresses, and capsular strains for each motion segment overlapped well under the two conditions. However, after 150 ms, the capsular strains of C2 to C6 without cranial acceleration applied on C7 were all obviously lower than those with cranial acceleration applied, but the segmental rotational angles and disc stresses remain unaffected. It was implied that, although without cranial acceleration applied on C7, the relatively simple head—neck model could be used to reflect effectively the biomechanical response of the cervical spine during the initial stage (i.e. 150 ms) under low-speed, rear-end impact as well as the whole-human-body dummy model.
Repeatability and contact stress gradient detection of sealed pressure-sensitive film when used in a physiological joint model
Authors: Matricali G A , Labey L , Bartels W , Dereymaeker G , Luyten F P , Vander Sloten J
Published: November 2008

Sealed pressure-sensitive film is frequently used to record contact characteristics in physiological joints. However, the effect on the pressure-recording characteristics of sealing the film when used in these circumstances has never been studied. This study compares the coefficient of variation, the standardized coefficient of variation, the tangent and secant contact stress gradients, and the actual pressures between unsealed and sealed Fuji film, in a simplified physiological joint model with a full-thickness surface defect. Unsealed film and sealed film were loaded through a range of nominal loads and the resulting stains were analysed by use of custom-made macros for the ImageJ image-processing program. The coefficient of variation did not exceed 5.7 per cent (sealed film), and the standardized coefficient of variation did not exceed 1.8 per cent (unsealed and sealed film). Contact stress gradients did not differ significantly. The recorded pressure at the level of surface defects was always about 0.2 MPa higher in the case of sealed film, and therefore predictable. It is concluded that sealing the film will not change the pressure-recording characteristics.
Development and experimental validation of a mathematical model for friction between fabrics and a volar forearm phantom
Authors: Cottenden A M , Cottenden D J , Karavokiros S , Wong W K R
Published: November 2008

An analytical mathematical model for friction between a fabric strip and the volar forearm has been developed and validated experimentally. The model generalizes the common assumption of a cylindrical arm to any convex prism, and makes predictions for pressure and tension based on Amontons' law. This includes a relationship between the coefficient of static friction ( μ) and forces on either end of a fabric strip in contact with part of the surface of the arm and perpendicular to its axis. Coefficients of friction were determined from experiments between arm phantoms of circular and elliptical cross-section (made from Plaster of Paris covered in Neoprene) and a nonwoven fabric. As predicted by the model, all values of μ calculated from experimental results agreed within ±8 per cent, and showed very little systematic variation with the deadweight, geometry, or arc of contact used. With an appropriate choice of coordinates the relationship predicted by this model for forces on either end of a fabric strip reduces to the prediction from the common model for circular arms. This helps to explain the surprisingly accurate values of μ obtained by applying the cylindrical model to experimental data on real arms.
Flow in valve covered orifice nozzles with cylindrical and tapered holes and link to cavitation erosion and engine exhaust emissions
Authors: Gavaises M
Published: November 2008

Results from a research programme addressing the development, testing, and production of valve covered orifice (VCO) nozzles operating with current production Tier 3 off-highway diesel engines are reviewed. The common rail injectors operate at pressures exceeding 1300 bar and include pilot and main injection events. Although acceptable engine exhaust emissions can be obtained with conventional VCO nozzles, cavitation erosion may lead to mechanical failure of the nozzle. Redesigning the injector in terms of its durability against surface erosion has been obtained through use of a computational fluid dynamics (CFD) flow solver incorporating a two-phase cavitation model and flow visualization in enlarged transparent nozzle replicas. The model has provided evidence of the flow distribution under realistic pressure and needle lift opening scenarios while at the same time it has been calibrated to indicate the locations where the possibility of cavitation erosion may become significant. The experiments performed in enlarged transparent nozzle replicas have provided evidence of the string cavitation structures formed inside the different nozzle designs. Cross-correlation with engine emission tests indicates that string cavitation may be associated with increased engine exhaust emissions. Proposed injector designs with geometric modification easily implemented in the production series have been proved to be erosion-free while at the same time have improved the engine exhaust emissions.
The first wide-open throttle engine cycle: Transition into knock experiments with fast in-cylinder sampling
Authors: Hamilton L J , Cowart J S
Published: November 2008

A gasoline cooperative fuels research (CFR) engine is used to evaluate the knock sensitivity for the first wide-open throttle (WOT) cycle during fast throttle transitions at various fuelling levels. A fast flame ionization detector (FFID) and fast non-dispersive infrared (NDIR) detector are used to determine an accurate in-cylinder air—fuel ratio. All tests are done with compression ratio = 9 and spark timing set to 20° BTC, conditions that normally result in moderate knock during steady state operation. It is found that audible knock occurs in 60–80 per cent of cases when in-cylinder P is between 1.05 and 1.35. However, if the first WOT cycle fuelling results in an in-cylinder air—fuel ratio slightly less than stoichiometric, knock remains inaudible. This slightly lean of stoichiometric fuelling also provides for the strongest gross indicated mean effective pressure due to appropriate combustion phasing without knock.
Analysis on the effective position of a reinforcement patch used as crack arrest for plates with mixed-mode (I/II) cracks
Authors: Wang F , Cui W
Published: November 2008

Rectangular patches are usually used as the temporary crack stoppers ahead of the tips of macro cracks. As mixed-mode cracks are usually initiated in engineering structures, the relative position of reinforcement patches to crack tips should be carefully considered. There will be many directions around crack tips for allocating reinforcement patches and the effectiveness of reinforcement patches should be quite dependent on their allocation positions, which can be expressed by the distance between the crack tip and patch, and also the direction of the patch relative to the crack line. The present paper will aim to examine the proper position for allocating the reinforcement patch by comparing the reduction level of the stress intensity factors. Finite element analysis will be conducted for this purpose. The optimum position for allocating the reinforcement patch will be determined, which will be further compared with crack propagation direction determined by strain energy density theory for an elastic cracked body. The conclusion is drawn that the patch with proper stiffness should be allocated in the direction of initial crack propagation near the crack tips. Its effectiveness will not be satisfactory when allocated away from the region.
Approximating the Stochastic Knapsack Problem: The Benefit of Adaptivity
Authors: Dean Brian C. , Goemans Michel X. , Vondrák Jan
Published: November 2008

We consider a stochastic variant of the NP-hard 0/1 knapsack problem, in which item values are deterministic and item sizes are independent random variables with known, arbitrary distributions. Items are placed in the knapsack sequentially, and the act of placing an item in the knapsack instantiates its size. Our goal is to compute a solution “policy” that maximizes the expected value of items successfully placed in the knapsack, where the final overflowing item contributes no value. We consider both nonadaptive policies (that designate a priori a fixed sequence of items to insert) and adaptive policies (that can make dynamic choices based on the instantiated sizes of items placed in the knapsack thus far). An important facet of our work lies in characterizing the benefit of adaptivity. For this purpose we advocate the use of a measure called the adaptivity gap: the ratio of the expected value obtained by an optimal adaptive policy to that obtained by an optimal nonadaptive policy. We bound the adaptivity gap of the stochastic knapsack problem by demonstrating a polynomial-time algorithm that computes a nonadaptive policy whose expected value approximates that of an optimal adaptive policy to within a factor of four. We also devise a polynomial-time adaptive policy that approximates the optimal adaptive policy to within a factor of 3 + ε for any constant ε > 0.
Femoral neck fracture following hip resurfacing
Authors: Davis E. T. , Olsen M. , Zdero R. , Waddell J. P. , Schemitsch E. H.
Published: November 2008

A total of 20 pairs of fresh-frozen cadaver femurs were assigned to four alignment groups consisting of relative varus (10° and 20°) and relative valgus (10° and 20°), 75 composite femurs of two neck geometries were also used. In both the cadaver and the composite femurs, placing the component in 20° of valgus resulted in a significant increase in load to failure. Placing the component in 10° of valgus had no appreciable effect on increasing the load to failure except in the composite femurs with varus native femoral necks. Specimens in 10° of varus were significantly weaker than the neutrally-aligned specimens.

The results suggest that retention of the intact proximal femoral strength occurs at an implant angulation of ≥ 142°. However, the benefit of extreme valgus alignment may be outweighed in clinical practice by the risk of superior femoral neck notching, which was avoided in this study.
Analysis of cover of the femoral head in normal and dysplastic hips
Authors: Dandachli W. , Kannan V. , Richards R. , Shah Z. , Hall-Craggs M. , Witt J.
Published: November 2008

We present a new CT-based method which measures cover of the femoral head in both normal and dysplastic hips and allows assessment of acetabular inclination and anteversion. A clear topographical image of the head with its covered area is generated.

We studied 36 normal and 39 dysplastic hips. In the normal hips the mean cover was 73% (66% to 81%), whereas in the dysplastic group it was 51% (38% to 64%). The significant advantage of this technique is that it allows the measurements to be standardised with reference to a specific anatomical plane. When this is applied to assessing cover in surgery for dysplasia of the hip it gives a clearer understanding of where the corrected hip stands in relation to normal and allows accurate assessment of inclination and anteversion.
Perthes’ disease and the search for genetic associations
Authors: Kenet G. , Ezra E. , Wientroub S. , Steinberg D. M. , Rosenberg N. , Waldman D. , Hayek S.
Published: November 2008

The role of heritable thrombophilic risk factors in the pathogenesis of the Perthes’ disease is controversial. The clinical and radiological findings of Perthes’ disease may be indistinguishable from those of Gaucher’s disease, and the most common Jewish N370S Gaucher mutation is threefold greater in patients with Perthes’ disease. Familial osteonecrosis of the femoral head is associated with variant mutations of collagen type II (COL2A1 mutations). We therefore studied the potential role of genetic thrombophilia and the Gaucher and COL2A1 mutations in children with Perthes’ disease.

Genomic DNA of 119 children with radiologically-confirmed Perthes’ disease diagnosed between 1986 and 2005 was analysed for the thrombophilic polymorphisms Factor V Leiden, 677T-MTHFR and FIIG20210A. The results were compared with those of a group of 276 children without Perthes’ disease. DNA was also analysed for the Gaucher mutations N370S, G insertion (84GG), L444P, Intron 2 (IVS2+1G> A) and R496H. Enzymic assays confirmed the Gaucher disease status. Collagen (COL2A1) mutations of the 12q13 gene were also analysed. The prevalence of thrombophilic markers was similar among the 119 patients with Perthes’ disease and the 276 control subjects. The prevalence of the Gaucher mutation was consistent with Israeli population carriership data and did not confirm an earlier-claimed association with Perthes’ disease. All 199 patients were negative for the studied COL2A1 mutations.

We found no genetic association between Perthes’ disease and either Gaucher’s disease or COL2A1 mutations or increased genetic thrombophilia among our patients compared with the control group. A systematic review of case-control studies suggested that there was a positive association between Perthes’ disease and Factor V Leiden. The impact of this association upon the disease, although not consistent across the studies, remains unclear.
The medium-term results of the cemented Exeter femoral component in patients under 40 years of age
Authors: de Kam D. C. J. , Klarenbeek R. L. W. A. , Gardeniers J. W. M. , Veth R. P. H. , Schreurs B. W.
Published: November 2008

We evaluated the outcome of 104 consecutive primary cemented Exeter femoral components in 78 patients (34 men, 44 women) under the age of 40 years who underwent total hip replacement between October 1993 and May 2004. The mean age at operation was 31 years (16 to 39). No hip was lost to follow-up, but three patients (four hips) died. None of the deaths were related to the surgery. At a mean follow-up of 6.2 years (2 to 13), three femoral components had been revised for septic loosening. Using Kaplan-Meier survival analysis, the seven-year survival of the component with revision for any reason as the endpoint was 95.8% (95% confidence interval 86.67 to 98.7). The seven-year survival with aseptic femoral loosening as the endpoint was 100% (95% confidence interval 100).

The cemented Exeter femoral component in patients under the age of 40 shows promising medium-term results. As it is available in a wide range of sizes and offsets, we could address all types of anatomical variation in this series without the need for custom-made components.
The effect of shortening and varus collapse of the femoral neck on function after fixation of intracapsular fracture of the hip
Authors: Zlowodzki M. , Brink O. , Switzer J. , Wingerter S. , Woodall J. , Petrisor B. A. , Kregor P. J. , Bruinsma D. R. , Bhandari M.
Published: November 2008

We have studied the effect of shortening of the femoral neck and varus collapse on the functional capacity and quality of life of patients who had undergone fixation of an isolated intracapsular fracture of the hip with cancellous screws. After screening 660 patients at four university medical centres, 70 patients with a mean age of 71 years (20 to 90) met the inclusion criteria. Overall, 66% (46 of 70) of the fractures healed with > 5 mm of shortening and 39% (27 of 70) with > 5° of varus. Patients with severe shortening of the femoral neck had significantly lower short form-36 questionnaire (SF-36) physical functioning scores (no/mild (< 5 mm) vs severe shortening (> 10 mm); 74 vs 42 points, p < 0.001). A similar effect was noted with moderate shortening, suggesting a gradient effect (no/mild (< 5 mm) vs moderate shortening (5 to 10 mm); 74 vs 53 points, p = 0.011). Varus collapse correlated moderately with the occurrence of shortening (r = 0.66, p < 0.001). Shortening also resulted in a significantly lower EuroQol questionnaire (EQ5D) index scores (p = 0.05). In a regression analysis shortening of the femoral neck was the only significant variable predictive of a low SF-36 physical functioning score (p < 0.001).
Ponseti casting
Authors: Brewster M. B. S. , Gupta M. , Pattison G. T. R. , Dunn-van der Ploeg I. D.
Published: November 2008

We have modified the Ponseti casting technique by using a below-knee Softcast instead of an above-knee plaster of Paris cast. Treatment was initiated as soon as possible after birth and the Pirani score was recorded at each visit. Following the manipulation techniques of Ponseti, a below-knee Softcast was applied directly over a stockinette for a snug fit and particular attention was paid to creating a deep groove above the heel to prevent slippage. If necessary, a percutaneous Achilles tenotomy was performed and casting continued until the child was fitted with Denis Browne abduction boots.

Between April 2003 and May 2007 we treated 51 consecutive babies with 80 idiopathic club feet with a mean age at presentation of 4.5 weeks (4 days to 62 weeks). The initial mean Pirani score was 5.5 (3 to 6). It took a mean of 8.5 weeks (4 to 53) of weekly manipulation and casting to reach the stage of percutaneous Achilles tenotomy. A total of 20 feet (25%) did not require a tenotomy and for the 60 that did, the mean Pirani score at time of operation was 2.5 (0.5 to 3). Denis Browne boots were applied at a mean of 10 weeks (4 to 56) after presentation. The mean time from tenotomy to boots was 3.3 weeks (2 to 10). We experienced one case of cast-slippage during a period of non-attendance, which prolonged the casting process. One case of prolonged casting required repeated tenotomy, and three feet required repeated tenotomy and casting after relapsing while in Denis Browne boots.

We believe the use of a below-knee Softcast in conjunction with Ponseti manipulation techniques shows promising initial results which are comparable to those using above-knee plaster of Paris casts.
Pre-operative predictors of the length of hospital stay in total knee replacement
Authors: Smith I. D. M. , Elton R. , Ballantyne J. A. , Brenkel I. J.
Published: November 2008

In Scotland, the number of primary total knee replacements performed annually has been increasing steadily. The price of the implant is fixed but the length of hospital stay is variable.

We prospectively investigated all patients who underwent primary unilateral total knee replacement in the Scottish region of Fife, between December 1994 and February 2007 and assessed their recorded pre-operative details. The data were analysed using univariate and multiple linear regression statistical analysis.

Data on the length of stay were available from a total of 2106 unilateral total knee replacements. The median length of hospital stay was eight days. The significant pre-operative risk factors for an increased length of stay were the year of admission, details of the consultant looking after the patient, the stair score, the walking-aid score and age.

Awareness of the pre-operative factors which increase the length of hospital stay may provide the opportunity to influence them favourably and to reduce the time in hospital and the associated costs of unilateral total knee replacement.
The value of radiographs obtained during forced traction under general anaesthesia in predicting flexibility in idiopathic scoliosis with Cobb angles exceeding 60°
Authors: Ibrahim T. , Gabbar O. A. , El-Abed K. , Hutchinson M. J. , Nelson I. W.
Published: November 2008

Our aim in this prospective radiological study was to determine whether the flexibility rate calculated from radiographs obtained during forced traction under general anaesthesia, was better than that of fulcrum-bending radiographs before corrective surgery in predicting the extent of the available correction in patients with idiopathic scoliosis. We evaluated 33 patients with a Cobb angle > 60° on a standing posteroanterior radiograph, who had been treated by posterior correction. Pre-operative standing fulcrum-bending radiographs and those with forced-traction under general anaesthesia were obtained. Post-operative standing radiographs were taken after surgical correction.

The mean forced-traction flexibility rate was 55% (sd 11.3) which was significantly higher than the mean fulcrum-bending flexibility rate of 32% (sd 16.1) (p < 0.001). We found no correlation between either the forced-traction or fulcrum-bending flexibility rates and the correction rate post-operatively (p = 0.24 and p = 0.44, respectively).

Radiographs obtained during forced traction under general anaesthesia were better at predicting the flexibility of the curve than fulcrum-bending radiographs in curves with a Cobb angle > 60° in the standing position and may identify those patients for whom supplementary anterior surgery can be avoided.
Arthroscopic release for painful subtalar stiffness after intra-articular fractures of the calcaneum
Authors: Lee K.-B. , Chung J.-Y. , Song E.-K. , Seon J.-K. , Bai L.-B.
Published: November 2008

We describe the surgical technique and results of arthroscopic subtalar release in 17 patients (17 feet) with painful subtalar stiffness following an intra-articular calcaneal fracture of Sanders’ type II or III. The mean duration from injury to arthroscopic release was 11.3 months (6.4 to 36) and the mean follow-up after release was 16.8 months (12 to 25). The patient was positioned laterally and three arthroscopic portals were placed anterolaterally, centrally and posterolaterally. The sinus tarsi and lateral gutter were debrided of fibrous tissue and the posterior talocalcaneal facet was released. In all, six patients were very satisfied, eight were satisfied and three were dissatisfied with their results. The mean American Orthopaedic Foot and Ankle Society ankle-hindfoot score improved from a mean of 49.4 points (35 to 66) pre-operatively to a mean of 79.6 points (51 to 95). All patients reported improvement in movement of the subtalar joint. No complications occurred following operation, but two patients subsequently required subtalar arthrodesis for continuing pain.

In the majority of patients a functional improvement in hindfoot function was obtained following arthroscopic release of the subtalar joint for stiffness and pain secondary to Sanders type II and III fractures of the calcaneum.
Histopathological and biochemical changes following fat embolism with administration of corn oil micelles
Authors: Liu D. D. , Hsieh N.-K. , Chen H. I.
Published: November 2008

Several experimental models have been used to produce intravascular fat embolism. We have developed a simple technique to induce fat embolism using corn oil emulsified with distilled water to form fatty micelles. Fat embolism was produced by intravenous administration of these fatty micelles in anaesthetised rats, causing alveolar oedema, haemorrhage and increased lung weight.

Histopathological examination revealed fatty droplets and fibrin thrombi in the lung, kidney and brain. The arteriolar lumen was filled with fatty deposits. Following fat embolism, hypoxia and hypercapnia occurred. The plasma phospholipase A2, nitrate/nitrite, methylguidanidine and proinflammatory cytokines were significantly increased. Mass spectrometry showed that the main ingredient of corn oil was oleic acid.

This simple technique may be applied as a new animal model for the investigation of the mechanisms involved in the fat embolism syndrome.
The Harris-Galante porous-coated, hemispherical, polyethylene-lined acetabular component in patients under 50 years of age
Authors: Utting M. R. , Raghuvanshi M. , Amirfeyz R. , Blom A. W. , Learmonth I. D. , Bannister G. C.
Published: November 2008

We have reviewed 70 Harris-Galante uncemented acetabular components implanted as hybrid hip replacements with cemented stems between 1991 and 1995 in 53 patients whose mean age was 40 years (19 to 49). The mean follow-up was for 13.6 years (12 to 16) with no loss to follow-up. We assessed the patients both clinically and radiologically.

The mean Oxford hip score was 20 (12 to 46) and the mean Harris hip score 81 (37 to 100) at the final review. Radiologically, 27 hips (39%) had femoral osteolysis, 13 (19%) acetabular osteolysis, and 31 (44%) radiolucent lines around the acetabular component. Kaplan-Meier survival curves were constructed for the outcomes of revision of the acetabular component, revision of the component and polyethylene liner, and impending revision for progressive osteolysis.

The cumulative survival for revision of the acetabular component was 94% (95% confidence interval 88.4 to 99.7), for the component and liner 84% (95% confidence interval 74.5 to 93.5) and for impending revision 55.3% (95% confidence interval 40.6 to 70) at 16 years.

Uncemented acetabular components with polyethylene liners undergo silent lysis and merit regular long-term radiological review.
Simultaneous anterior decompression and posterior instrumentation of the tuberculous spine using an anterolateral extrapleural approach
Authors: Jain A. K. , Dhammi I. K. , Prashad B. , Sinha S. , Mishra P.
Published: November 2008

Injury to the spinal cord and kyphosis are the two most feared complications of tuberculosis of the spine. Since tuberculosis affects principally the vertebral bodies, anterior decompression is usually recommended. Concomitant posterior instrumentation is indicated to neutralise gross instability from panvertebral disease, to protect the anterior bone graft, to prevent graft-related complications after anterior decompression in long-segment disease and to correct a kyphosis. Two-stage surgery is usually performed in these cases. We present 38 consecutive patients with tuberculosis of the spine for whom anterior decompression, posterior instrumentation, with or without correction of the kyphus, and anterior and posterior fusion was performed in a single stage through an anterolateral extrapleural approach. Their mean age was 20.4 years (2.0 to 57.0).

The indications for surgery were panvertebral disease, neurological deficit and severe kyphosis. The patients were operated on in the left lateral position using a ‘T’-shaped incision sited at the apex of kyphosis or lesion. Three ribs were removed in 34 patients and two in four and anterior decompression of the spinal cord was carried out. The posterior vertebral column was shortened to correct the kyphus, if necessary, and was stabilised by a Hartshill rectangle and sublaminar wires. Anterior and posterior bone grafting was performed.

The mean number of vertebral bodies affected was 3.24 (2.0 to 9.0). The mean pre-operative kyphosis in patients operated on for correction of the kyphus was 49.08° (30° to 72°) and there was a mean correction of 25° (6° to 42°). All except one patient with a neural deficit recovered complete motor and sensory function. The mean intra-operative blood loss was 1175 ml (800 to 2600), and the mean duration of surgery 3.5 hours (2.7 to 5.0). Wound healing was uneventful in 33 of 38 patients. The mean follow-up was 33 months (11 to 74). None of the patients required intensive care.

The extrapleural anterolateral approach provides simultaneous exposure of the anterior and posterior aspects of the spine, thereby allowing decompression of the spinal cord, posterior stabilisation and anterior and posterior bone grafting. This approach has much less morbidity than the two-stage approaches which have been previously described.
The cytotoxic effect of phenol and ethanol on the chondrosarcoma-derived cell line OUMS-27
Authors: Verdegaal S. H. M. , Corver W. E. , Hogendoorn P. C. W. , Taminiau A. H. M.
Published: November 2008

Surgery is considered to be the most effective treatment for cartilaginous tumours. In recent years, a trend has emerged for patients with low-grade tumours to be treated less invasively using curettage followed by various forms of adjuvant therapy. We investigated the potential for phenol to be used as an adjuvant. Using a human chondrosarcoma-derived cartilage-producing cell line OUMS-27 as an in vitro model we studied the cytotoxic effect of phenol and ethanol. Since ethanol is the standard substance used to rinse phenol out of a bone cavity, we included an assessment of ethanol to see whether this was an important secondary factor with respect to cell death. The latter was assessed by flow cytometry.

A cytotoxic effect was found for concentrations of phenol of 1.5% and of ethanol of 42.5%. These results may provide a clinical rationale for the use of both phenol and ethanol as adjuvant therapy after intralesional curettage in low-grade central chondrosarcoma and justify further investigation.