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1.
Disabil Rehabil ; : 1-9, 2024 Jul 08.
Artigo em Inglês | MEDLINE | ID: mdl-38975724

RESUMO

PURPOSE: Research suggests that rates for autism may be higher in cerebral palsy than in the general population. For those with severe bilateral physical impairment (GMFCS level IV and V) and little or no speech, describing a profile of social communication skills has been difficult because there are currently no assessments for early social communication specifically tailored for these children. Our aim was to explore the assessment of aspects of joint attention and social reciprocity in this group of children with CP. METHODS: We compared the performance of children with bilateral CP on carefully designed assessments of joint attention and social responsiveness with groups of children with Down syndrome and autism. All three groups were matched for chronological age and mental age. RESULTS: Approximately 30% of the children with bilateral CP had early social communication scores similar to the autistic children. The remaining 70% of children with CP had a range of early social communication scores similar to the children with Down syndrome. CONCLUSION: It is possible to assess key early social communication skills in non-speaking children with bilateral motor disability. This could provide insights to help clinicians and caregivers as they discuss abilities and explore potential areas for intervention.


With carefully designed activities, which do not rely on motor skills or verbal exchanges, it was possible to assess joint attention and social responsiveness skills in a group of non-speaking children with bilateral motor disability.We were able to identify a subgroup of non-speaking children with severe motor disability (approximately 30% of our cohort) whose scores on our assessments were similar to a group of autistic children.The ability to describe key early social communication skills should provide insights to help clinicians and caregivers as they discuss abilities and explore potential areas for intervention.

2.
Augment Altern Commun ; : 1-8, 2024 May 22.
Artigo em Inglês | MEDLINE | ID: mdl-38775646

RESUMO

The relationships between the use of nouns and verbs, and other word classes have been well established in the typical language development literature. However, questions remain as to whether the same relationships are seen in the language use of individuals who use graphic symbol-based augmentative and alternative communication (AAC). The aim of the study was to examine relationships between the use of verbs and nouns, and the use of prepositions, adverbs, and adjectives through a secondary analysis of language transcripts taken from 12 children and adolescents who used aided AAC in conversation with an adult. A series of multiple linear mixed-effect regression analyses showed a positive predictive association between the use of verbs and the use of prepositions and adverbs, as well as a positive predictive relationship between the use of nouns and the use of adjectives. The theoretical and practical implications of these findings are discussed.

3.
Dev Neurorehabil ; 27(1-2): 27-33, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38676395

RESUMO

This paper explores whether a structured history-taking tool yields useful descriptions of children's looking skills. Parents of 32 children referred to a specialist communication clinic reported their child's looking skills using the Functional Vision for Communication Questionnaire (FVC-Q), providing descriptions of single object fixation, fixation shifts between objects and fixation shifts from object to person. Descriptions were compared with clinical assessment. 24/32 children were reported to have some limitation in fixation. Limitation was subsequently seen in 30/32 children. Parental report and assessment agreed fully in 23/32 (72%). The largest area of discrepancy was object-person fixation shifts, with five children not observed to show this behavior despite its being reported. Findings indicate a structured questionnaire yields description of fixations, which correspond well with clinical assessment. Descriptions supported discussion between parents and clinicians. It is proposed that the FVC-Q is a valuable tool in supporting clinicians in eliciting information about fixation skills.


Assuntos
Comunicação , Pais , Humanos , Feminino , Criança , Inquéritos e Questionários , Masculino , Pré-Escolar , Fixação Ocular/fisiologia , Adolescente , Anamnese
4.
Disabil Rehabil Assist Technol ; : 1-8, 2023 Dec 19.
Artigo em Inglês | MEDLINE | ID: mdl-38112177

RESUMO

PURPOSE: Little is known about how children learn to control eye-gaze technology, and clinicians lack information to guide decision-making. This paper examines whether typically developing 2-3 year olds can infer for themselves the causal mechanisms by which eye-gaze technology is controlled, whether a teaching intervention based on causal language improves performance and how their performance compares to the same task accessed via a touchscreen.Methods and materials: Typically developing children's (n = 9, Mean Age 28.7 months) performance on a cause and effect game presented on eye-gaze and touchscreen devices was compared. The game was presented first with no specific instruction on how to control the devices. This was followed by a subsequent presentation with explicit instruction about how the access methods worked, using a causal language approach. A final presentation examined whether children had retained any learning. RESULTS: Performance in the eye-gaze condition without instruction (42.5% successful trials) was significantly below performance in the corresponding touchscreen condition (75%). However, when causal language instruction was added, performance with both access methods rose to comparable levels (90.7% eye-gaze and 94.6% touchscreen success). Performance gains were not retained post-intervention. CONCLUSIONS: Although 2-3 years in the study could make use of eye-gaze technology with support, this study found no evidence that these children could infer the causal mechanisms of control independently or intuitively. The lack of spatial contiguity and the comparative lack of feedback from eye-gaze devices are discussed as possible contributory factors.


There are challenges in young children inferring for themselves the causal link between eye movements and control of an eye-gaze device.Explicit instruction may improve children's performance in a specific task, but it is debatable whether this translates to the establishment of causal mechanisms for control of the device.Clinicians should be cautious of making assumptions about what children are learning from activities claiming to teach cause and effect or other foundational eye-gaze control skills.

5.
Augment Altern Commun ; 39(4): 293-301, 2023 12.
Artigo em Inglês | MEDLINE | ID: mdl-37671918

RESUMO

The present study investigated the relationship between lexicon and grammar in individuals who use graphic symbol-based aided augmentative and alternative communication (AAC). Data came from 60 transcripts of generalization sessions that were part of two previous intervention studies, aimed at improving the expressive vocabulary and grammar of 12 children and youth who used graphic symbol-based AAC. The specific aims of the current study were to (a) describe vocabulary composition across different levels of expressive vocabulary and (b) analyze the relationship between global measures of expressive vocabulary and the use of grammar in individuals who use aided AAC. A series of multiple linear mixed effect regression analyses showed a positive predictive association between overall vocabulary size and the use of closed-class words, and a positive relationship between the use of verbs and the use of closed-class words. Additionally, the use of verbs had a significant positive association with the use of inflectional morphology, while the use of nouns did not. Theoretical and practical implications of these findings are discussed.


Assuntos
Auxiliares de Comunicação para Pessoas com Deficiência , Transtornos da Comunicação , Humanos , Criança , Adolescente , Linguística , Vocabulário , Idioma
6.
Int J Lang Commun Disord ; 57(4): 700-716, 2022 07.
Artigo em Inglês | MEDLINE | ID: mdl-35373429

RESUMO

BACKGROUND: Recent evidence suggests that pre-school children with co-occurring phonological speech sound disorder (SSD) and expressive language difficulties are at a higher risk of ongoing communication and literacy needs in comparison with children with these difficulties in isolation. However, to date there has been no systematic or scoping review of the literature specific to interventions for children with this dual profile. AIMS: To explore the evidence regarding interventions for pre-school children with co-occurring phonological SSD and expressive language difficulties, including the content/delivery of such interventions, areas of speech and language targeted, and a broad overview of study quality. METHODS & PROCEDURES: A scoping review methodology was used in accordance with the guidance from the Joanna Briggs Institute. Following a systematic search of Ovid Medline, Ovid Emcare, OVID Embase, CINAHL, Psychinfo and ERIC, 11 studies were included in the review. A researcher-developed data extraction form was used to extract specific information about each intervention, with the JBI appraisal tools used to provide a broad overview of the quality of each study. MAIN CONTRIBUTION: Included papers consisted of six randomized controlled trials (RCTs), two cohort studies, two case studies and one case series. Interventions fell into two main categories: (1) integrated interventions that combined content for both speech and language targets and/or explicitly used the same type of technique to improve both domains; and (2) single-domain interventions that explicitly included content to target speech or language only, but also aimed to improve the other domain indirectly. Study quality varied, with detail on the content, context and delivery of interventions often underspecified, hampering the replication and clinical applicability of findings. CONCLUSIONS & IMPLICATIONS: Early emerging evidence was identified to support both integrated speech and language interventions as well as single-domain interventions. However, caution should be exercised due to the variation in the quality and level of detail reported for the interventions. Future intervention studies may seek to address this by reporting in accordance with Template for Intervention Description and Replication (TIDieR) reporting guidelines. This approach would enable clinicians to consider the applicability of the intervention to individual children within differing settings. WHAT THIS PAPER ADDS: What is already known on the subject Pre-school children with co-occurring phonological SSD and expressive language difficulties frequently present within speech and language therapy services. These children are at a higher risk of long-term communication and literacy difficulties compared with children with these needs in isolation. Some emerging evidence suggests that interventions for children with this co-occurring profile may exist within the literature; however, this evidence may not be known to clinicians in everyday practice. What this paper adds to existing knowledge This review is the first to systematically examine evidence of interventions for pre-school children with co-occurring phonological SSD and expressive language difficulties. The review identified a small number of intervention studies that varied in research quality and level of detail provided regarding the content and delivery of interventions. What are the potential or actual clinical implications of this work? The findings of this study highlight published evidence for interventions for pre-school children with co-occurring phonological SSD and expressive language difficulties. These may take the form of integrating techniques for speech/language into a single intervention, or the explicit targeting of one domain with the aim of also influencing the other. However, there is a need for further high-quality research in this area. Such studies should provide sufficient detail to enable replication. This would enable clinicians to understand the relevance and applicability of such intervention findings to the individual children they see within their clinical practice.


Assuntos
Transtorno Fonológico , Criança , Pré-Escolar , Humanos , Terapia da Linguagem/métodos , Fonética , Fala , Transtorno Fonológico/terapia , Fonoterapia/métodos
7.
Disabil Rehabil ; 44(8): 1451-1456, 2022 04.
Artigo em Inglês | MEDLINE | ID: mdl-32783539

RESUMO

PURPOSE: The aim of this study was to develop and test a new classification scale to describe looking behaviours (gaze fixations and gaze shifts) in relation to eye-pointing. METHODS: The Eye-pointing Classification Scale (EpCS) was developed and tested following established procedures for the construction and evaluation of equivalent scales, and involved 2 phases: Drawing on research literature, Phase 1 involved initial drafting of the scale through a series of multi-disciplinary group discussions; evaluation of the scale through a survey procedure, and subsequent expert group evaluation. Phase 2, was an examination of scale reliability and relationships between child characteristics and level of EpCS classification. RESULTS: In Phase 1, an initial draft of the scale was developed and then evaluated by 52 participants in 10 countries, leading to its refinement. Subsequent expert evaluation of content, style and structure indicated that no further refinement was required. In Phase 2, the scale achieved excellent levels of reliability in clinical testing. A significant relationship was identified between level of child motor ability and EpCS classification, and level of child language understanding and EpCS classification.Implications for rehabilitationNon-speaking children with severe bilateral cerebral palsy who have limited upper limb movement may communicate by using controlled looking behaviours to point to objects and people, referred to as eye-pointing.However, there is little consensus as to which looking behaviours represent eye-pointing and which do not.The Eye-pointing Classification Scale (EpCS) was developed to describe looking behaviours related to eye-pointing in this population of childrenThe EpCS provides a new robust tool for clinical management and research with children with cerebral palsy.


Assuntos
Paralisia Cerebral , Criança , Fixação Ocular , Humanos , Movimento , Reprodutibilidade dos Testes , Extremidade Superior
8.
Augment Altern Commun ; 37(4): 251-260, 2021 12.
Artigo em Inglês | MEDLINE | ID: mdl-34967282

RESUMO

Conversational repair has been found to play a fundamental role in the acquisition of language. This paper describes existing research on conversational repair and its relationship to language learning, whether a first language or a second language, as well as its relevance to augmentative and alternative communication (AAC). A case is made for incorporating prompts to repair in conversation-based language interventions with children learning to use AAC. We argue that interventions targeting linguistic complexity should encourage self-repair in conversation in order to develop linguistic and operational competency as well as increase automaticity when using AAC. Clinical implications and directions for future research are discussed.


Assuntos
Auxiliares de Comunicação para Pessoas com Deficiência , Transtornos da Comunicação , Criança , Comunicação , Humanos , Idioma , Desenvolvimento da Linguagem
9.
BMC Neurol ; 21(1): 63, 2021 Feb 10.
Artigo em Inglês | MEDLINE | ID: mdl-33568101

RESUMO

BACKGROUND: Limited research exists to guide clinical decisions about trialling, selecting, implementing and evaluating eye-gaze control technology. This paper reports on the outcomes of a Delphi study that was conducted to build international stakeholder consensus to inform decision making about trialling and implementing eye-gaze control technology with people with cerebral palsy. METHODS: A three-round online Delphi survey was conducted. In Round 1, 126 stakeholders responded to questions identified through an international stakeholder Advisory Panel and systematic reviews. In Round 2, 63 respondents rated the importance of 200 statements generated by in Round 1. In Round 3, 41 respondents rated the importance of the 105 highest ranked statements retained from Round 2. RESULTS: Stakeholders achieved consensus on 94 of the original 200 statements. These statements related to person factors, support networks, the environment, and technical aspects to consider during assessment, trial, implementation and follow-up. Findings reinforced the importance of an individualised approach and that information gathered from the user, their support network and professionals are central when measuring outcomes. Information required to support an application for funding was obtained. CONCLUSION: This Delphi study has identified issues which are unique to eye-gaze control technology and will enhance its implementation with people with cerebral palsy.


Assuntos
Paralisia Cerebral , Tomada de Decisão Clínica , Fixação Ocular , Tecnologia/instrumentação , Interface Usuário-Computador , Adolescente , Adulto , Criança , Consenso , Técnica Delphi , Feminino , Humanos , Masculino , Inquéritos e Questionários
10.
J Child Lang ; 47(1): 250-264, 2020 01.
Artigo em Inglês | MEDLINE | ID: mdl-31524119

RESUMO

The present study investigated the effects of different types of recasts and prompts on the rate of repair and spontaneous use of novel vocabulary by eight children with severe motor speech disabilities who used speech-generating technologies to communicate. Data came from 60 transcripts of clinical sessions that were part of a conversation-based intervention designed to teach them pronouns, verbs, and verb inflections. The results showed that, when presented alone, interrogative choice and declarative recasts led to the highest rates of child repair. The results also showed that when children were presented with recasts and prompts to repair, the rate of repair increased. Spontaneous use of linguistic targets was significantly and positively related to conversational sequences where the adult recast was followed by child repair. These findings suggest that using different recast types and prompts to repair may be beneficial for spontaneous use of linguistic targets in this population.


Assuntos
Auxiliares de Comunicação para Pessoas com Deficiência , Idioma , Distúrbios da Fala/reabilitação , Vocabulário , Adolescente , Apraxias/complicações , Apraxias/reabilitação , Paralisia Cerebral/complicações , Paralisia Cerebral/reabilitação , Criança , Feminino , Humanos , Desenvolvimento da Linguagem , Linguística , Masculino , Fala , Distúrbios da Fala/etiologia
11.
Augment Altern Commun ; 34(3): 180-193, 2018 09.
Artigo em Inglês | MEDLINE | ID: mdl-30043650

RESUMO

This study evaluated the effects of a conversation-based intervention on the use of verbs, personal pronouns, bound morphemes and spontaneous clauses in adolescents with cerebral palsy who use augmentative and alternative communication (AAC). Four teenage girls aged from 14 to 18 years participated in the study. After a baseline period, a conversation-based intervention was provided for each participant in the context of a personal collage-building activity. The conversations were videotaped, transcribed, and analyzed using the Systematic Analysis of Language Transcripts (SALT™) . While the results are mixed, all four participants increased their use of at least one linguistic target, three increased their use of verbs and grammatically correct spontaneous clauses, two increased their use of personal pronouns, and one produced more bound morphemes during intervention than in baseline. These findings, and future research needs, are discussed.


Assuntos
Paralisia Cerebral/reabilitação , Auxiliares de Comunicação para Pessoas com Deficiência , Transtornos da Comunicação/reabilitação , Comunicação , Relações Interpessoais , Grupo Associado , Adolescente , Feminino , Humanos
12.
J Speech Lang Hear Res ; 60(7): 1980-1998, 2017 07 12.
Artigo em Inglês | MEDLINE | ID: mdl-28672283

RESUMO

Purpose: This study was conducted to evaluate the effects of a conversation-based intervention on the expressive vocabulary and grammatical skills of children with severe motor speech disorders and expressive language delay who use augmentative and alternative communication. Method: Eight children aged from 8 to 13 years participated in the study. After a baseline period, a conversation-based intervention was provided for each participant, in which they were supported to learn and use linguistic structures essential for the formation of clauses and the grammaticalization of their utterances, such as pronouns, verbs, and bound morphemes, in the context of personally meaningful and scaffolded conversations with trained clinicians. The conversations were videotaped, transcribed, and analyzed using the Systematic Analysis of Language Transcripts (SALT; Miller & Chapman, 1991). Results: Results indicate that participants showed improvements in their use of spontaneous clauses, and a greater use of pronouns, verbs, and bound morphemes. These improvements were sustained and generalized to conversations with familiar partners. Conclusion: The results demonstrate the positive effects of the conversation-based intervention for improving the expressive vocabulary and grammatical skills of children with severe motor speech disorders and expressive language delay who use augmentative and alternative communication. Clinical and theoretical implications of conversation-based interventions are discussed and future research needs are identified. Supplemental Materials: https://doi.org/10.23641/asha.5150113.


Assuntos
Auxiliares de Comunicação para Pessoas com Deficiência , Transtornos do Desenvolvimento da Linguagem/reabilitação , Linguística , Distúrbios da Fala/reabilitação , Adolescente , Criança , Feminino , Humanos , Transtornos do Desenvolvimento da Linguagem/complicações , Transtornos do Desenvolvimento da Linguagem/psicologia , Testes de Linguagem , Masculino , Reprodutibilidade dos Testes , Distúrbios da Fala/complicações , Distúrbios da Fala/psicologia , Resultado do Tratamento
13.
Augment Altern Commun ; 33(1): 42-50, 2017 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-28166652

RESUMO

For children with typical development, language is learned through everyday discursive interaction. Adults mediate child participation in such interactions through the deployment of a range of co-constructive strategies, including repeating, questioning, prompting, expanding, and reformulating the child's utterances. Adult reformulations of child utterances, also known as recasts, have also been shown to relate to the acquisition of linguistic structures in children with language and learning disabilities and children and adults learning a foreign language. In this paper we discuss the theoretical basis and empirical evidence for the use of different types of recasts as a major language learning catalyst, and what may account for their facilitative effects. We consider the occurrence of different types of recasts in AAC-mediated interactions and their potential for language facilitation, within the typical operational and linguistic constraints of such interactions. We also consider the benefit of explicit and corrective forms of recasts for language facilitation in conversations with children who rely on AAC. We conclude by outlining future research directions.


Assuntos
Auxiliares de Comunicação para Pessoas com Deficiência , Transtornos da Comunicação/reabilitação , Desenvolvimento da Linguagem , Aprendizagem , Criança , Pré-Escolar , Humanos
14.
Res Dev Disabil ; 33(6): 2058-66, 2012.
Artigo em Inglês | MEDLINE | ID: mdl-22750668

RESUMO

Children with a clinical description of cerebral palsy (CP) commonly experience cognitive and sensory difficulties that co-occur with motor impairment, and for some children this can include impairments in social communication. While research has begun to examine theory of mind abilities in children with CP, relatively little is known about social communication difficulties in this population. Assessing theory of mind abilities in children with CP using traditional procedures such as the classic Sally-Anne task can be problematic if performance is affected by physical difficulties in signalling responses and/or by cognitive and language demands inherent to the task itself. The central aim of this study therefore was to examine the potential of using a new action anticipation task and eye-tracking technique to assess implicit true and false belief understanding in four developmentally young children with quadriplegic cerebral palsy who had little or no functional speech, and one language age matched child with Down syndrome who did not have severe motor impairment. All children in this study consistently demonstrated anticipatory gaze behaviours in the context of the true belief task. One child with CP and the child with Down syndrome demonstrated anticipatory gaze behaviours indicative of an ability to attribute false belief. The findings are discussed in relation to the application of action anticipation and eye-tracking paradigms in research and clinical practice.


Assuntos
Paralisia Cerebral/psicologia , Cultura , Movimentos Oculares , Teoria da Mente , Pré-Escolar , Compreensão , Síndrome de Down/psicologia , Feminino , Humanos , Masculino , Comunicação não Verbal , Projetos Piloto
15.
J Arthroplasty ; 22(1): 109-16, 2007 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-17197317

RESUMO

We compared the mechanical and morphological characteristics of cement-bone structures created with either standard- or low-viscosity cement using a human cadaver model that simulated intramedullary bleeding. The goal is to determine if the viscosity of the cement would affect the strength of the cement-bone interface and the degree of apposition between the cement and bone. The tensile strength of cement-bone constructs with standard-viscosity cement (2.42 +/- 1.55 MPa) was 21% stronger than with low-viscosity cement (2.00 +/- 1.51 MPa, P = .034). Cement-bone apposition was positively correlated (r2 = 0.29, P <. 0001) with the strength of the interface. There was 15% greater apposition between cement and bone (P = .036) for standard-viscosity cement. Low-viscosity cement may be less effective in displacing bone marrow and in preventing hemodynamic backflow, resulting in less apposition and a weaker interface.


Assuntos
Artroplastia de Quadril/métodos , Perda Sanguínea Cirúrgica/prevenção & controle , Cimentos Ósseos , Medula Óssea/cirurgia , Idoso de 80 Anos ou mais , Fenômenos Biomecânicos , Cadáver , Humanos , Teste de Materiais , Modelos Anatômicos , Viscosidade
16.
J Med Libr Assoc ; 95(1): 56-63, 2007 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-17252067

RESUMO

PURPOSE: To describe the journal reading patterns of pediatrician members of the American Academy of Pediatrics (AAP) and compare results to similar surveys of medical faculty and physicians. The research also explored factors that might influence changes in reading patterns in the future, such as adoption of PDA technology. METHODOLOGY: A random sample of 2,000 AAP members was drawn from the AAP membership list, with paper surveys distributed in mid-2004. SETTINGS/SUBJECTS: Six hundred sixty-six pediatrician AAP members participated in a survey of reading behavior, with a total of 1,351 members answering some questions about technology use. RESULTS: The hypotheses that pediatricians read many journal articles each month, read each article on average quite quickly, read heavily from personal subscriptions, read from both print and electronic journals, and read for many purposes were all supported. Pediatricians read journal articles primarily for current awareness and most often rely on quick reading from print journals for current awareness. Reading for research, writing, and presentations are more likely from library-provided electronic journals. DISCUSSION/CONCLUSION: Convenience and purpose of reading are key factors that explain reading patterns of pediatricians. Print personal subscriptions are convenient for current awareness reading, while electronic journals systems are convenient for reading for research because they provide access to a broader range of journals. Publishers and librarians must understand the purposes and patterns of reading to design appropriate journals and services. Pediatricians read many current articles very quickly and from many different locations. Pediatricians under the age of thirty-five are more likely to use PDAs, suggesting that articles delivered to a handheld device might be accepted as convenient in the future.


Assuntos
Atitude do Pessoal de Saúde , Conhecimentos, Atitudes e Prática em Saúde , Internet/estatística & dados numéricos , Jornalismo Médico , Pediatria , Médicos/estatística & dados numéricos , Competência Clínica , Humanos , Inquéritos e Questionários , Estados Unidos
17.
J Orthop Res ; 25(3): 340-50, 2007 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-17149748

RESUMO

A combination of laboratory experiment and computational simulation was performed to assess the role of interface porosity on stem migration. The early motion of in vitro prepared cemented femoral components was measured during application of cyclic stair climbing loads. Following testing, transverse sections were obtained and the distribution of pores at the stem-cement interface was determined. Finite element models of cemented stem constructs were developed and a scheme was implemented to randomly assign pores to the stem-cement interface. For a series of 14 in vitro prepared components, pore fractions at the stem-cement interface ranged from 23% to 67%. The majority of pores at the stem-cement interface were less than 1 mm in length with a mean length of 1.27 +/- 2.7 mm and thickness of 0.12 +/- 0.11 mm. For stems with large pore fractions, pores tended to coalesce in longer extended gaps over the stem surface. Finite element and experimental models both revealed strong positive correlations (r(2) = 0.55-0.72; p < 0.0001) between stem-cement pore fraction and stem internal rotation, suggesting that the presence and extent of pores could explain the early motion of the stems. There was an increased volume of cement at risk of fatigue failure with increasing stem migration. Pore fractions greater than 30% resulted in large increases in stem internal rotation, suggesting that attempts to maintain surface porosity at or below this level may be desirable to minimize the risk of clinical loosening.


Assuntos
Artroplastia de Quadril/efeitos adversos , Cimentos Ósseos/química , Cimentação/efeitos adversos , Fêmur/cirurgia , Falha de Prótese , Idoso , Idoso de 80 Anos ou mais , Artroplastia de Quadril/instrumentação , Humanos , Técnicas In Vitro , Pessoa de Meia-Idade , Porosidade
18.
Acta Orthop ; 77(4): 607-16, 2006 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-16929438

RESUMO

BACKGROUND: Limited data exist on the performance of low-viscosity cement in clinically realistic cadaver models. METHODS: Paired stem/cement/femur constructs were generated with low-viscosity and standard-viscosity cements. The constructs were created and tested under simulated in vivo conditions, for which novel techniques were developed during this study. Mantle function was quantified by stem/cortex micromotions over 105cycles of "stair-climbing". Mantle morphology was determined from transverse sections. RESULTS: Penetration of low-viscosity cement was greater proximally but less distally (p = 0.02). Low-viscosity cement resulted in more stem retroversion (p = 0.04), but there was no difference in subsidence (p = 0.4). Low-viscosity cement mantles had greater fractions of non-apposed interface (p = 0.006). Fraction of non-apposed interface predicted stem retroversion (R2 = 0.64, p = 0.002). INTERPRETATION: Low-viscosity cement resulted in inferior cement mantles. Early micromotion was reduced by better interface apposition. The greater stem retroversion of low-viscosity cement would probably lead to higher revision rates. Early stem migration is due to interface non-apposition. Techniques should be developed to reduce non-apposition of cemented interfaces.


Assuntos
Artroplastia de Quadril/métodos , Cimentos Ósseos , Fêmur/patologia , Idoso , Idoso de 80 Anos ou mais , Fenômenos Biomecânicos , Cadáver , Fêmur/irrigação sanguínea , Fêmur/fisiopatologia , Humanos , Teste de Materiais , Modelos Biológicos , Viscosidade
19.
Acta Orthop ; 76(5): 679-87, 2005 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-16263615

RESUMO

BACKGROUND: The Norwegian Arthroplasty Register reported that CMW3 cement performed poorly for femoral stem fixation. METHODS: We implanted collared, satin-finished stems (Ra = 0.35 microm) into cadaver femora using CMW3 and with Simplex as control. Cement mantle function was quantified by stem migration after 300,000 cycles of "stair climbing". Cement cracks and interface gaps were quantified in transverse sections. RESULTS: The variances of the CMW3 migrations were substantially higher than for the control (p < 0.001): subsidence for CMW3: -32 (SD 42) microm, and for Simplex: -7 (SD 9) microm (p = 0.2); retroversion for CMW3: 0.60 degrees (SD 0.25), and for Simplex: 0.37 degrees (SD 0.04) (p = 0.08). Crack length-densities were similar. CMW3 had significantly more non-apposed stem/cement interface: 52% (SD 17) versus 33% (SD 8) (p = 0.04). Migrations could be predicted by the fraction of non-apposed stem/cement interface (retroversion: R(2)=0.80, p < 0.001; subsidence: R(2) = 0.46, p = 0.02) but not by cement cracks or non-apposed cement-bone interface. INTERPRETATION: We found that increased stem/cement non-apposition resulted in increased stem migration. Early migration is known to correlate with risk of revision. Thus, the higher stem-revision risk for CMW3 cement reported by the Norwegian Arthroplasty Register may have been due to inferior and variable stem/cement apposition.


Assuntos
Artroplastia de Quadril/efeitos adversos , Cimentos Ósseos , Prótese de Quadril/efeitos adversos , Falha de Prótese , Fenômenos Biomecânicos , Cadáver , Cimentação/efeitos adversos , Humanos , Teste de Materiais , Desenho de Prótese , Reoperação , Fatores de Risco , Viscosidade
20.
J Arthroplasty ; 20(4): 542-6, 2005 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-16124974

RESUMO

Metal-on-metal is one potential bearing option for total hip arthroplasty (THA). Proponents of the bearing have suggested that if the tribology is optimal, volumetric wear may occur at levels at least one order of magnitude lower than metal-on-polyethylene bearings. We present a unique postmortem case of a well fixed, metal-on-metal, McKee-Farrar total hip arthroplasty implanted 30 years previously that was clinically asymptomatic in life. Clinical and radiological examination is supplemented by tribological examination of the bearing and histopathological examination of the cement-bone interface.


Assuntos
Artroplastia de Quadril/instrumentação , Prótese de Quadril , Humanos , Masculino , Pessoa de Meia-Idade , Desenho de Prótese
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