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1.
SICOT J ; 5: 40, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31674904

RESUMO

INTRODUCTION: Chronic liver disease (CLD) is a significant and increasingly prevalent co-morbidity in patients undergoing total hip arthroplasty (THA). These patients may develop metabolic bone disease (MBD) and systemic dysfunction, which pose challenges to THA surgery. This systematic review of literature aims to examine clinical outcomes and complications in patients with CLD undergoing THA and provide evidence-based approaches as to the optimization of their perioperative care. METHODS: A Pubmed search was performed, identifying eight studies on 28 514 THAs for inclusion. Two additional studies reported on 44 patients undergoing THA post liver transplant. These were reviewed separately. RESULTS: Increased early perioperative complications are reported recurrently. Review of long-term complications demonstrates an increased postoperative infection rate of 0.5% (p < 0.001) and perioperative mortality of 4.1% (p < 0.001). The need for revision surgery is more frequent at 4% (p < 0.001). Aetiology of need for revision surgery included; periprosthestic infection (70%), aseptic loosening (13%), instability (13%), periprosthetic fracture (2%) and liner wear (2%). THA in patients with liver transplants seems to offer functional improvement; however, no studies have formally assessed functional outcomes in the patient with active CLD. DISCUSSION: A multidisciplinary perioperative approach is suggested in order to minimize increased complication risks. Specific measures include optimizing haemoglobin and taking measures to reduce infection. This review also highlights gaps in available literature and guides future research to appraise functional outcomes, further detail long-term failure reasons and study any differences in outcomes and complications based on the range of operative approaches and available implant choices.

2.
Arch Orthop Trauma Surg ; 139(4): 553-560, 2019 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-30778723

RESUMO

INTRODUCTION: The increasing prevalence of obesity has led to an increase in total knee arthroplasties (TKAs) being undertaken in patients with a higher body mass index (BMI). TKA in morbidly obese patients can be technically challenging due to numerous anatomical factors and patient co-morbidities. The long-term outcomes in this patient group are unclear. This systematic review aims to compare the long-term revision rates, functional outcomes and complication rates of TKAs in morbidly obese versus non-obese patients. METHODS: A search of PubMed, EMBASE and PubMed Central was conducted to identify studies that reported revision rates in a cohort of morbidly obese patients (BMI ≥ 40 kg/m2) that underwent primary TKA, compared to non-obese patients (BMI ≤ 30 kg/m2). Secondary outcomes included Knee Society Objective Scores (KSOS), Knee Society Functional Scores (KSFS), and complication rates between the two groups. The difference in revision rates was assessed using the Chi-squared test. The Wilcoxon signed-rank test was used to compare pre-operative and post-operative functional scores for each group. KSOS and KSFS for morbidly obese and non-obese patients were compared using the Mann-Whitney test. Statistical significance was defined as p ≤ 0.05. RESULTS: Nine studies were included in this review. There were 624 TKAs in morbidly obese patients and 9,449 TKAs in non-obese patients, average BMI values were 45.0 kg/m2 (range 40-66 kg/m2) and 26.5 kg/m2 (range 11-30 kg/m2) respectively. The average follow-up time was 4.8 years (range 0.5-14.1) and 5.2 years (range 0.5-13.2) respectively, with a revision rate of 7% and 2% (p < 0.001) respectively. All functional scores improved after TKA (p < 0.001). Pre- and post-operative KSOS and KSFS were poorer in morbidly obese patients, however, mean improvement in KSOS was the same in both groups and comparable between groups for KSFS (p = 0.78). Overall complication rates,  including infection, were higher in morbidly obese patients. CONCLUSIONS: This review suggests an increased mid to long-term revision rate following primary TKA in morbidly obese patients, however, these patients have a functional recovery which is comparable to non-obese individuals. There is also an increased risk of perioperative complications, such as superficial wound infection. Morbidly obese patients should be fully informed of these issues prior to undergoing primary TKA.


Assuntos
Artroplastia do Joelho , Obesidade Mórbida/epidemiologia , Artroplastia do Joelho/efeitos adversos , Artroplastia do Joelho/estatística & dados numéricos , Estudos de Coortes , Humanos , Resultado do Tratamento
3.
EFORT Open Rev ; 3(9): 507-512, 2018 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-30305935

RESUMO

The increasing prevalence of obesity has resulted in a marked increase in the number of total hip arthroplasties (THAs) carried out in patients with a high body mass index (BMI).THA in morbidly obese patients is often technically challenging owing to the associated co-morbidities and anatomical factors. Furthermore, the long-term clinical and functional outcomes of the procedure in these patients are not clear.The aim of this systematic review was to compare the long-term failure rate and functional outcomes of THA in morbidly obese versus non-obese patients.A literature search of PubMed, EMBASE and PubMed Central was conducted to identify studies that compared the outcomes of THA in patients defined as morbidly obese (BMI ≥ 35) to a control group (BMI < 30). The primary and secondary outcome measures were rate of revision and functional outcome, respectively, in the long term.Eight studies were included in this review. There were 66,238 THAs in morbidly obese patients and 705,619 THAs in patients with a BMI < 30. The overall revision rate was 7.99% in the morbidly obese patients versus 2.75% in the non-obese controls. The functional outcome was at least comparable to non-obese patients.This review suggests that morbidly obese patients have a slightly increased revision rate following THA. Importantly, these patients have a functional recovery at least comparable to those with a BMI < 30. Morbidly obese patients should be fully informed of these issues prior to undergoing surgery. Cite this article: EFORT Open Rev 2018;3:507-512. DOI: 10.1302/2058-5241.3.180011.

4.
World J Orthop ; 9(10): 229-234, 2018 Oct 18.
Artigo em Inglês | MEDLINE | ID: mdl-30364786

RESUMO

AIM: To determine the functional outcomes, complications and revision rates following total knee arthroplasty (TKA) in patients with Paget's disease of bone (PDB). METHODS: A systematic review of the literature was performed. Four studies with a total of 54 TKAs were included for analysis. Functional outcomes, pain scores, complications and revision rates were assessed. The mean age was 72.0 years and the mean follow-up was 7.5 years. RESULTS: All studies reported significant improvement in knee function and pain scores following TKA. There were 2 cases of aseptic loosening, with one patient requiring revision of the femoral component 10 years after the index procedure. Malalignment, bone loss, soft tissue contractures were the most commonly reported intra-operative challenges. There were five cases (9%) that were complicated by intra-operative patellar tendon avulsion. CONCLUSION: The findings support the use of TKA in patients with PDB. The post-operative functional outcomes are largely similar to other patients, however there are specific perioperative challenges that have been highlighted, in particular the high risk for patellar tendon avulsion.

5.
EFORT Open Rev ; 3(6): 358-362, 2018 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-30034816

RESUMO

Total knee arthroplasty (TKA) in patients affected by poliomyelitis is technically challenging owing to abnormal anatomical features including articular and metaphyseal angular deformities, external rotation of the tibia, excessive valgus alignment, bone loss, narrowness of the femoral and tibial canals, impaired quadriceps strength, flexion contractures, genu recurvatum and ligamentous laxity. Little information is available regarding the results and complications of TKA in this challenging group of patients.We carried out a systematic review of the literature to determine the functional outcome, complications and revision rates of TKA in patients with poliomyelitis-affected knees. Six studies including 82 knees met the inclusion criteria and were reviewed. The mean patient age was 63 years (45 to 85) and follow-up was 5.5 years (0.5 to 13).All studies reported significant improvement in knee function following TKA. There were six failures requiring revision surgery in 82 cases (7%) occurring at a mean of 6.2 years (0.4 to 12). The reasons for revision surgery were aseptic loosening (17%, n=1), infection (33%, n=2), periprosthetic fracture (17%, n=1) and instability (33%, n=2). Thirty-six knees had a degree of recurvatum pre-operatively (44%), which was in the range of 5° to 30°. Ten of these knees (28%) developed recurrent recurvatum post-operatively.The findings support the use of TKA in patients with poliomyelitis-affected knees. The post-operative functional outcome is similar to other patients; however, the revision rate is higher. Quadriceps muscle power appears to be an important prognostic factor for functional outcome and the use of constrained implant designs is recommended in the presence of less than antigravity quadriceps strength. Cite this article: EFORT Open Rev 2018;3:358-362. DOI: 10.1302/2058-5241.3.170028.

6.
World J Orthop ; 8(4): 357-363, 2017 Apr 18.
Artigo em Inglês | MEDLINE | ID: mdl-28473965

RESUMO

AIM: To investigate the clinical and functional outcomes following total hip arthroplasty (THA) in patients with Paget's disease. METHODS: We carried out a systematic review of the literature to determine the functional outcome, complications and revision rates of THA in patients with Paget's disease. Eight studies involving 358 hips were reviewed. The mean age was 70.4 years and follow-up was 8.3 years. There were 247 cemented THAs (69%), 105 uncemented THAs (29%) and 6 hybrid THAs (2%). RESULTS: All studies reported significant improvement in hip function following THA. There were 19 cases of aseptic loosening (5%) at a mean of 8.6 years. Three cases occurred in the uncemented cohort (3%) at a mean of 15.3 years and 16 cases developed in the cemented group (6%) at a mean of 7.5 years (P = 0.2052). There were 27 revisions in the 358 cases (8%) occurring at a mean of 7 years. Six revisions occurred in the uncemented cohort (6%) at a mean of 8.6 years and 21 in the cemented cohort (9%) at a mean of 6.5 years (P = 0.5117). CONCLUSION: The findings support the use of THA in patients with Paget's disease hip arthropathy. The post-operative functional outcome is largely similar to other patients; however, the revision rate is higher with aseptic loosening being the most common reason for revision. Uncemented implants appear to be associated with a lower failure rate, however, there were no modern stem designs fixed using current generation cementing techniques used in the reported studies, and as such, caution is advised when drawing any conclusions.

7.
Magn Reson Med ; 62(2): 544-9, 2009 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-19526515

RESUMO

The double-echo-steady-state (DESS) sequence generates two signal echoes that are characterized by a different contrast behavior. Based on these two contrasts, the underlying T2 can be calculated. For a flip-angle of 90 degrees , the calculated T2 becomes independent of T1, but with very low signal-to-noise ratio. In the present study, the estimation of cartilage T2, based on DESS with a reduced flip-angle, was investigated, with the goal of optimizing SNR, and simultaneously minimizing the error in T2. This approach was validated in phantoms and on volunteers. T2 estimations based on DESS at different flip-angles were compared with standard multiecho, spin-echo T2. Furthermore, DESS-T2 estimations were used in a volunteer and in an initial study on patients after cartilage repair of the knee. A flip-angle of 33 degrees was the best compromise for the combination of DESS-T2 mapping and morphological imaging. For this flip angle, the Pearson correlation was 0.993 in the phantom study (approximately 20% relative difference between SE-T2 and DESS-T2); and varied between 0.429 and 0.514 in the volunteer study. Measurements in patients showed comparable results for both techniques with regard to zonal assessment. This DESS-T2 approach represents an opportunity to combine morphological and quantitative cartilage MRI in a rapid one-step examination.


Assuntos
Algoritmos , Cartilagem Articular/anatomia & histologia , Aumento da Imagem/métodos , Interpretação de Imagem Assistida por Computador/métodos , Imageamento por Ressonância Magnética/métodos , Adulto , Humanos , Imageamento por Ressonância Magnética/instrumentação , Masculino , Imagens de Fantasmas , Reprodutibilidade dos Testes , Sensibilidade e Especificidade
8.
Eur Radiol ; 19(5): 1246-52, 2009 May.
Artigo em Inglês | MEDLINE | ID: mdl-19057903

RESUMO

The aims of this study were to examine the clinical feasibility and reproducibility of kinematic MR imaging with respect to changes in T (2) in the femoral condyle articular cartilage. We used a flexible knee coil, which allows acquisition of data in different positions from 40 degrees flexion to full extension during MR examinations. The reproducibility of T (2) measurements was evaluated for inter-rater and inter-individual variability and determined as a coefficient of variation (CV) for each volunteer and rater. Three different volunteers were measured twice and regions of interest (ROIs) were selected by three raters at different time points. To prove the clinical feasibility of this method, 20 subjects (10 patients and 10 age- and sex-matched volunteers) were enrolled in the study. Inter-rater variability ranged from 2 to 9 and from 2 to 10% in the deep and superficial zones, respectively. Mean inter-individual variability was 7% for both zones. Different T (2) values were observed in the superficial cartilage zone of patients compared with volunteers. Since repair tissue showed a different behavior in the contact zone compared with healthy cartilage, a possible marker for improved evaluation of repair tissue quality after matrix-associated autologous chondrocyte transplantation (MACT) may be available and may allow biomechanical assessment of cartilage transplants.


Assuntos
Fenômenos Biomecânicos , Cartilagem Articular/patologia , Cartilagem Articular/transplante , Imageamento por Ressonância Magnética/métodos , Adulto , Estudos de Casos e Controles , Condrócitos/metabolismo , Meios de Contraste/farmacologia , Feminino , Humanos , Processamento de Imagem Assistida por Computador , Articulação do Joelho/patologia , Articulação do Joelho/cirurgia , Masculino , Reprodutibilidade dos Testes , Software
9.
Invest Radiol ; 42(6): 442-8, 2007 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-17507817

RESUMO

OBJECTIVES: To evaluate magnetic resonance (MR) T2 mapping for characterization of cartilage repair tissue following matrix-associated autologous cartilage transplantation (MACT). MATERIALS AND METHODS: Fifteen patients were evaluated following MACT using a 3T MR scanner. Patients were categorized into 2 postoperative intervals: I: 3-13 months, II: 19-42 months. Mean T2 relaxation times calculated from multiple spin-echo sequence were determined in regions of interest (MACT and normal hyaline cartilage) and T2 line profiles through the repair tissue and control sites were acquired. RESULTS: Mean global T2 values of repair tissue in group I were significantly higher than at control sites (P < 0.05). Repair tissue in group II showed no significant difference to control sites. Repair tissue T2 line profiles normalized over time toward the control sites. CONCLUSIONS: T2 mapping allows visualization of cartilage repair tissue maturation. Global T2 repair tissue values approach that of control sites after more than 1.5 years, similar behavior is seen in the zonal organization.


Assuntos
Cartilagem Articular/citologia , Condrócitos/transplante , Imageamento por Ressonância Magnética/métodos , Adulto , Análise de Variância , Estudos Transversais , Feminino , Humanos , Articulação do Joelho , Masculino , Pessoa de Meia-Idade , Transplante Autólogo
10.
Spine (Phila Pa 1976) ; 32(2): 244-8, 2007 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-17224821

RESUMO

STUDY DESIGN: Prospective in vitro study of meniscoids in the cervical zygapophysial joints. OBJECTIVES.: To assess the use of high-field magnetic resonance imaging (MRI) as a potential tool for evaluating meniscoids of the cervical zygapophysial joints. SUMMARY OF BACKGROUND DATA: Pain originating from the cervical spine is a frequent condition. It has been suggested that pathologic conditions of meniscoids within the zygapophysial joints may cause pain. METHODS: Six zygapophysial joints from one embalmed human body were investigated with a 3.0-T MR unit, equipped with a microimaging-set. MRIs were correlated with microanatomical sections. RESULTS: High-quality images of the meniscoids were obtained for all joints examined. There was a good correlation between the anatomic features derived from MRI and the microanatomical sections. CONCLUSIONS: High-field MRI was successfully implemented as a noninvasive method for imaging the meniscoids in cervical zygapophysial joints. The results of this in vitro study indicate that high-field MRI may be feasible in evaluating patients with cervical pain possibly related to meniscoid pathology.


Assuntos
Vértebras Cervicais/anatomia & histologia , Imageamento por Ressonância Magnética/métodos , Articulação Zigapofisária/anatomia & histologia , Anatomia Transversal , Cadáver , Cartilagem Articular/anatomia & histologia , Estudos de Viabilidade , Humanos , Masculino , Pessoa de Meia-Idade , Estudos Prospectivos
11.
J Orthop Res ; 25(2): 143-51, 2007 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-17019682

RESUMO

The objectives of this study were to quantitatively evaluate the articular cartilage layers of the ankle and describe the cartilage topographical distribution across the joint surfaces using high resolution MRI and image segmentation. An anisotropic diffusion noise reduction algorithm and a directional gradient vector flow (dGVF) snake segmentation algorithm were applied to cartilage sensitive MR images. Eight cadaveric ankles were studied. Six repeated data sets were acquired in five of the ankles. Quantitative parameters were calculated for each cartilage layer; coefficients of variation (CV) were calculated from the six repeated data sets; and 3D thickness distribution maps were generated. The noise reduction algorithm produced marked image enhancement. Mean cartilage thickness ranged from 0.91 +/- 0.08 mm in the fibula to 1.34 +/- 0.14 mm in the talus. Mean cartilage volume was 3.32 +/- 0.55 ml, 1.72 +/- 0.25 ml, and 0.35 +/- 0.06 ml for the talus, tibia, and fibula, respectively. Mean CV ranged 2.82%-5.04% for quantitative parameters in the talus and tibia. The reported noise reduction and segmentation technique allow precise extraction of ankle cartilage and 3D reconstructions show that the thickest cartilage occurs over the talar shoulders, where osteochondritits dissecans (OCD) lesions commonly occur.


Assuntos
Articulação do Tornozelo/patologia , Cartilagem Articular/patologia , Imageamento por Ressonância Magnética/métodos , Algoritmos , Articulação do Tornozelo/anatomia & histologia , Cadáver , Cartilagem Articular/anatomia & histologia , Fíbula/patologia , Humanos , Masculino , Pessoa de Meia-Idade , Reprodutibilidade dos Testes , Tíbia/patologia
12.
Int Orthop ; 30(6): 519-24, 2006 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-16944144

RESUMO

Due to the advances in oncological therapy, the life expectancy of patients with malignant tumours and the incidence of pathological fractures have increased over the last decades. Pathological fractures of the long bones are common complications of metastatic disease; however, the outcome of different surgical techniques for the treatment of these fractures has not been clearly defined. The aim of this study was to evaluate differences in patient's survival and postoperative complications after the treatment of pathological fractures of the long bones. Eighty-eight patients with 96 pathological fractures of the long bones were analysed retrospectively. Seventy-five patients with 83 fractures received surgical treatment. The operative treatments used were intramedullary fixation, gliding screws, plate osteosynthesis or arthroplasty. Five patients were still alive at the end of data collection at a median time of 42.5 months, and 16.2% survived 1 year, 7% 2 years and 4% more than 3 years postoperatively. All surgically treated patients had a reduction of local pain and were able to walk after the operation. The overall rate of complications was 8%. Early palliative treatment of pathological fractures of the long bones is indicated in most patients in the advanced stage of metastatic disease. The low complication rate, reduction of local pain and early mobilisation justify the surgical stabilisation of fractures in this cohort of patients.


Assuntos
Ossos do Braço/lesões , Neoplasias Ósseas/secundário , Fixação de Fratura/métodos , Fraturas Espontâneas/cirurgia , Ossos da Perna/lesões , Cuidados Paliativos , Idoso , Idoso de 80 Anos ou mais , Neoplasias Ósseas/complicações , Feminino , Fixação de Fratura/efeitos adversos , Humanos , Masculino , Pessoa de Meia-Idade , Estudos Retrospectivos , Análise de Sobrevida
13.
Traffic Inj Prev ; 7(3): 299-305, 2006 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-16990245

RESUMO

OBJECTIVE: This article assesses the position-dependent injury tolerance of the hip in the frontal direction based on testing of eight postmortem human subjects. METHODS: For each subject, the left and right hemipelvis complex was axially loaded using a previously developed test configuration. Six positions were defined from a seated femur neutral condition, combining flexed, neutral, and extended femur positions with abducted, neutral, and adducted positions. RESULTS: Axial injury tolerances based on peak force were found to be 6,850 +/- 840 N in the extended, neutral position and 4,080 +/- 830 N in the flexed, neutral position. From the flexed neutral orientation, the peak axial force increased 18% for 20 degrees abduction and decreased 6% for 20 degrees adduction. From the extended, neutral orientation, the peak axial force decreased 4% for 20 degrees abduction and decreased 3% for 20 degrees adduction. However, as there is evidence that increases in loading may occur after the initiation of fracture, the magnitude of the peak force is likely related to the extent of injury, not to the initial tolerance. Using the axial femur force at the initiation of fracture (assessed with acoustic crack sensors) as a potentially more relevant indicator of injury may lower the existing injury criteria. This fracture initiation force varied by position from 3,010 +/- 560 N in the flexed, neutral position to 5,470 N in the extended, abducted position. Further, there was a large position-dependent variation in the ratio of fracture initiation force to the peak axial force. The initiation of fracture was 83% of the peak axial force in the extended, abducted position, but the ratio was 34% in the extended, adducted position. CONCLUSIONS: This may have significant implications for the development of pelvic injury criteria by automobile designers attempting to mitigate pelvis injuries.


Assuntos
Escala Resumida de Ferimentos , Acidentes de Trânsito , Fraturas Ósseas/fisiopatologia , Ossos Pélvicos/lesões , Adulto , Idoso , Fenômenos Biomecânicos , Cadáver , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Ossos Pélvicos/fisiopatologia
14.
IEEE Trans Biomed Eng ; 53(5): 896-907, 2006 May.
Artigo em Inglês | MEDLINE | ID: mdl-16686412

RESUMO

The accuracy of the surface extraction of magnetic resonance images of highly congruent joints with thin articular cartilage layers has a significant effect on the percentage errors and reproducibility of quantitative measurements (e.g., thickness and volume) of the articular cartilage. Traditional techniques such as gradient-based edge detection are not suitable for the extraction of these surfaces. This paper studies the extraction of articular cartilage surfaces using snakes, and a gradient vector flow (GVF)-based external force is proposed for this application. In order to make the GVF snake more stable and converge to the correct surfaces, directional gradient is used to produce the gradient vector flow. Experimental results show that the directional GVF snake is more robust than the traditional GVF snake for this application. Based on the newly developed snake model, an articular cartilage surface extraction algorithm is developed. Thickness is computed based on the surfaces extracted using the proposed algorithm. In order to make the thickness measurement more reproducible, a new thickness computation approach, which is called T-norm, is introduced. Experimental results show that the thickness measurement obtained by the new thickness computation approach has better reproducibility than that obtained by the existing thickness computation approaches.


Assuntos
Algoritmos , Cartilagem Articular/anatomia & histologia , Cartilagem Articular/fisiologia , Aumento da Imagem/métodos , Interpretação de Imagem Assistida por Computador/métodos , Imageamento Tridimensional/métodos , Reconhecimento Automatizado de Padrão/métodos , Artefatos , Inteligência Artificial , Cadáver , Humanos , Técnicas In Vitro , Imageamento por Ressonância Magnética , Masculino , Pessoa de Meia-Idade , Reprodutibilidade dos Testes , Sensibilidade e Especificidade , Propriedades de Superfície
15.
Foot Ankle Int ; 26(8): 602-6, 2005 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-16115416

RESUMO

BACKGROUND: Adhesive capsulitis of the ankle is a challenging diagnostic and therapeutic problem. Limited information concerning diagnosis and treatment is available in the musculoskeletal literature. METHODS: This study retrospectively reviewed a series of patients treated with corticosteroid injections or arthroscopic debridement of posttraumatic adhesive capsulitis of the ankle. The Foot Function Index was used to assess the final treatment outcomes. RESULTS: Forty-one patients with chronic posttraumatic ankle pain were identified. Five were confirmed to have posttraumatic adhesive capsulitis by arthrogram. Four of the five patients failed to respond to steroid injections and three had arthroscopic surgery. Foot Function Index scores indicated that two of these patients treated with arthroscopic debridement had improved function. CONCLUSIONS: Results of small series and information from the literature suggest that intra-articular injection of corticosteroid followed by arthroscopic synovectomy and scar resection can be effective as treatment for posttraumatic adhesive capsulitis of the ankle.


Assuntos
Traumatismos do Tornozelo/complicações , Artroscopia , Bursite/cirurgia , Desbridamento , Corticosteroides/uso terapêutico , Adulto , Bursite/tratamento farmacológico , Bursite/etiologia , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Estudos Retrospectivos
16.
Inf Process Med Imaging ; 19: 406-17, 2005.
Artigo em Inglês | MEDLINE | ID: mdl-17354713

RESUMO

This paper presents a general graph-theoretic technique for simultaneously segmenting multiple closed surfaces in volumetric images, which employs a novel graph-construction scheme based on triangulated surface meshes obtained from a topological presegmentation. The method utilizes an efficient graph-cut algorithm that guarantees global optimality of the solution under given cost functions and geometric constraints. The method's applicability to difficult biomedical image analysis problems was demonstrated in a case study of co-segmenting the bone and cartilage surfaces in 3-D magnetic resonance (MR) images of human ankles. The results of our automated segmentation were validated against manual tracings in 55 randomly selected image slices. Highly accurate segmentation results were obtained, with signed surface positioning errors for the bone and cartilage surfaces being 0.02 +/- 0.11mm and 0.17 +/- 0.12mm, respectively.


Assuntos
Tornozelo/anatomia & histologia , Cartilagem Articular/anatomia & histologia , Interpretação de Imagem Assistida por Computador/métodos , Imageamento Tridimensional/métodos , Imageamento por Ressonância Magnética/métodos , Reconhecimento Automatizado de Padrão/métodos , Ossos do Tarso/anatomia & histologia , Algoritmos , Inteligência Artificial , Humanos , Aumento da Imagem/métodos , Reprodutibilidade dos Testes , Sensibilidade e Especificidade
17.
Stapp Car Crash J ; 48: 1-26, 2004 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-17230259

RESUMO

Forced dorsiflexion in frontal vehicle crashes is considered a common cause of injury to the ankle joint. Although a few studies have been published on the dynamic fracture tolerance of the ankle in dorsiflexion, this work reexamines the topic with increased statistical power, adds an evaluation of articular cartilage injury, and utilizes methods to detect the true time of fracture. The objective of this study was to measure the response and injury tolerance of the human ankle in a loading condition similar to that found in a vehicle crash with toepan intrusion. A test fixture was constructed to apply forefoot impacts to twenty cadaveric lower limbs, that were anatomically intact distal to the femur mid-diaphysis. Specimen instrumentation included implanted tibial and fibular load cells, accelerometers, angular rate sensors, and an acoustic sensor. Following the tests, specimens were radiographed and dissected to determine the extent of injury. Eleven of the twenty specimens sustained fracture of the ankle joint. Fractures of the medial malleolus were the most common, while two specimens sustained bimalleolar fractures, and two a talar neck fracture. Other injuries included ligament tears, osteochondral fractures, and cartilage abrasions. Analysis of the acoustic emission indicated that fracture did not always occur at the peak ankle moment. Based on the results of this study, an ankle joint moment of 59 N-m represents a 25% risk of ankle fracture in dorsiflexion for a 50(th) percentile male. When applied to the Thor-Lx dummy, the 25% risk of injury occurs at 36 degrees of dorsiflexion as measured by the ankle potentiometer.

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