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1.
Technol Health Care ; 28(4): 415-423, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-31796715

RESUMO

BACKGROUND: There is a clear tendency towards cementless acetabular components in primary total hip arthroplasty. OBJECTIVE: The aim of this study was to assess the long-term clinical and radiological outcome of titanium cementless acetabular cups when combined with a highly crosslinked polyethylene liner. METHODS: This study is a retrospective follow-up of 67 cups in 64 patients. Clinical outcomes were assessed using the Harris Hip Score. Radiolucent lines, osteolysis and loosening were assessed radiologically. Implant survival was determined using the Kaplan-Meier analysis. RESULTS: The average Harris Hip Score at follow-up was 80.3 ± 14.5. Signs of osteolysis were observed in 7.1% of the radiographs. No aseptic loosening of the cup was reported. Survival of the cup with aseptic loosening as an endpoint was 100%. A comparison with 19 other studies using the same material combination demonstrated very similar results. All manufacturers with available studies have at least one report of 100% survivorship at 10-year follow-up for their titanium cup and highly crosslinked polyethylene acetabular component combination with aseptic loosening as an endpoint. CONCLUSIONS: The data suggests that the rate of aseptic loosening of a titanium cup combined with a highly-crosslinked polyethylene liner at 10-year follow-up could be as low as 0%.


Assuntos
Acetábulo , Artroplastia de Quadril , Acetábulo/cirurgia , Seguimentos , Prótese de Quadril , Humanos , Polietileno , Desenho de Prótese , Falha de Prótese , Estudos Retrospectivos , Titânio
2.
Arch Orthop Trauma Surg ; 138(9): 1317-1322, 2018 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-30043147

RESUMO

INTRODUCTION: This stem was cleared by the FDA in 2002 and has been implanted in cementless and cemented versions. Despite its long history, there are no long-term clinical  results available for the cemented version of this implant. The aim of this study was to provide such data. It was hypothesized that this implant delivers clinical success comparable to other tapered cemented stems. MATERIALS AND METHODS: A total of 113 hip replacements were performed in 106 patients between October 2007 and December 2009 using the cemented version of this stem. The mean age of the patients at operation was 74.8 years (range 50-91 years). The mean follow-up was 8.9 years with only two patients lost to follow-up. Implant survival was determined using the Kaplan-Meier analysis. RESULTS: Stem survival with revision for any reason as the endpoint was 96.4% after 10 years. Survival for stem aseptic loosening was 100%. There were no cases of osteolysis. Clinical outcomes, as shown by Harris Hip Scores, were in line with previous investigations and the rate of adverse events was very low. CONCLUSIONS: This is a modern cemented stem with an excellent survival rate and satisfactory functional outcomes. In this cohort, there were no failures related to the stem through the first decade.


Assuntos
Artroplastia de Quadril/instrumentação , Cimentos Ósseos/uso terapêutico , Prótese de Quadril/efeitos adversos , Idoso , Idoso de 80 Anos ou mais , Artroplastia de Quadril/métodos , Cimentos Ósseos/efeitos adversos , Feminino , Seguimentos , Articulação do Quadril/cirurgia , Humanos , Estimativa de Kaplan-Meier , Masculino , Pessoa de Meia-Idade , Estudos Prospectivos , Desenho de Prótese/efeitos adversos , Falha de Prótese/etiologia , Reoperação/estatística & dados numéricos , Resultado do Tratamento
3.
Technol Health Care ; 26(5): 825-832, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-29914043

RESUMO

BACKGROUND: Knee and hip replacement surgery are still the mainstay therapy for osteoarthritis. In spite of the improvement of techniques and implants, anemia is a relatively common complication, with transfusion rates of up to 23% in some centers. OBJECTIVE: The purpose of the study was to determine a correlation of transfusions to complications including infection since this topic is still being debated or even disputed in the literature. METHODS: This is a level III, single center retrospective observational cohort study of 2760 unilateral primary knee and hip replacements. Preoperative assessment, the number of transfusions and the occurrence of complications were collected and the correlations were analyzed using analysis of variance and logistic regression. RESULTS: Fifteen percent of all patients developed at least one complication. Transfusion rate was 9%. Risk factors for receiving a transfusion were female gender, hip replacement, American Society of Anesthesiologists' Score (ASA) > III, history of myocardial infarction, chronic cardiac disease, diabetes mellitus, chronic kidney disease, and length of surgery. The risk factors for developing a complication were: ASA score, presence of chronic renal insufficiency, and transfusion during hospital stay. Transfusion increases the risk of complications and infection rate. Complication rate with transfusion was 34.7% and without transfusion 13.2%. Infection rate without transfusion was 0.4% and with transfusion 2.82%. CONCLUSIONS: The complication rate is higher in transfused patients. The number of complications rises linearly with the number of transfusions. Infection rate is also higher after a transfusion. Efforts should be made to reduce the transfusion rate.


Assuntos
Artroplastia de Quadril/métodos , Artroplastia do Joelho/métodos , Transfusão de Sangue/estatística & dados numéricos , Infecção da Ferida Cirúrgica/epidemiologia , Adulto , Fatores Etários , Idoso , Idoso de 80 Anos ou mais , Artroplastia de Quadril/efeitos adversos , Artroplastia do Joelho/efeitos adversos , Comorbidade , Feminino , Humanos , Tempo de Internação/estatística & dados numéricos , Modelos Logísticos , Masculino , Pessoa de Meia-Idade , Duração da Cirurgia , Complicações Pós-Operatórias/epidemiologia , Estudos Retrospectivos , Fatores de Risco , Fatores Sexuais
4.
Technol Health Care ; 26(3): 523-528, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-29578494

RESUMO

BACKGROUND: An increasing demand for total knee arthroplasty (TKA) has pushed innovations in the industry and created a promising new technique called patient specific instruments (PSI). Early reports had promising results such as reducing operative time, cost, and improved alignment. More recent reports are conflicting. OBJECTIVE: We aimed to evaluate bleeding, operative time, complication rates, and in-hospital stay. METHODS: A monocentric retrospective analysis was performed on a total of 961 patients that met inclusion criteria. Four different TKA Systems, two of which were performed using conventional instrumentation (CI) (n= 768) and two with PSI (n= 193) were trialed under the same conditions by three senior surgeons. Operative time, complications, bleeding, range of motion, and length of stay were analyzed. RESULTS: There was no difference in operative time (p= 0.991) and length of hospital stay (p= 0.371) between PSI and CI approaches. Complication rates were lower in the PSI group. CI patients showed less non-compensated blood loss (p< 0.001) but required more transfusions (5.8% vs. 1.5%, p= 0.014). CONCLUSIONS: There was no difference in duration of surgery, length of stay, and total blood loss when performing TKA with PSI or CI. There were fewer complications in the PSI group. It remains debatable whether these findings justify routine use of PSI in TKA.


Assuntos
Artroplastia do Joelho/instrumentação , Artroplastia do Joelho/métodos , Idoso , Idoso de 80 Anos ou mais , Perda Sanguínea Cirúrgica , Feminino , Humanos , Tempo de Internação , Masculino , Pessoa de Meia-Idade , Duração da Cirurgia , Osteoartrite do Joelho/cirurgia , Complicações Pós-Operatórias/epidemiologia , Amplitude de Movimento Articular , Estudos Retrospectivos
5.
BMC Musculoskelet Disord ; 19(1): 8, 2018 01 09.
Artigo em Inglês | MEDLINE | ID: mdl-29316902

RESUMO

BACKGROUND: Ankle tape is widely used by athletes to prevent ankle sprain. Although there is growing evidence that ankle tape improve joint position sense, but yet it is not clear even if tape improve joint position sense after muscle fatigue, because fatigue impair joint position sense and raise the risk of ankle sprain. The aim of this study is to examine the effect of ankle tape on joint position sense after local muscle fatigue. METHOD: This trial is a randomized controlled trial. 34 healthy subjects participated in this trial. Subjects were randomized distributed into two groups: with tape and without tape. Active and passive absolute error and variable error mean values for two target positions of the ankle joint (15° inversions and inversion minus 5°) before and after fatigue protocol consisted of 30 consecutive maximal concentric/concentric contractions of the ankle evertors and invertors. In this trail joint position sense for all subjects was assessed using The Biodex System isokinetic dynamometer 3, this system is used also for fatigue protocol. RESULTS: For the variable error (VE), significant mean effect was found for active joint position sense in 15° of inversion after muscle fatigue (P < 0, 05). It was a significant decrease in the work in the last third of inversion detected (P < 0, 05). There was no significant main effect found for fatigue index of eversion. CONCLUSION: Ankle tape can improve joint position sense at the fatigue session when joint position sense becomes worse. As a result, ankle tape may be useful to prevent ankle sprain during playing sports. We suggest athletes and individuals at risk of ankle sprain to apply taping before high-load activity. TRIAL REGISTRATION: The study was retrospectively registered on the ISRCTN registry with study ID ISRCTN30042335 on 12th December 2017.


Assuntos
Articulação do Tornozelo/fisiologia , Fita Atlética/estatística & dados numéricos , Fadiga Muscular/fisiologia , Propriocepção/fisiologia , Adulto , Traumatismos do Tornozelo/fisiopatologia , Traumatismos do Tornozelo/prevenção & controle , Feminino , Humanos , Masculino , Resultado do Tratamento
6.
BMC Musculoskelet Disord ; 18(1): 439, 2017 Nov 10.
Artigo em Inglês | MEDLINE | ID: mdl-29126408

RESUMO

BACKGROUND: Acromioclavicular joint (ACJ) dislocations are common injuries of the shoulder associated with physical activity. The diagnosis of concomitant injuries proves complicated due to the prominent clinical symptoms of acute ACJ dislocation. Because of increasing use of minimally invasive surgery techniques concomitant pathologies are diagnosed more often than with previous procedures. METHODS: The aim of this study was to identify the incidence of concomitant intraarticular injuries in patients with high-grade acromioclavicular separation (Rockwood type III - V) as well as to reveal potential risk constellations. The concomitant pathologies were compiled during routine arthroscopically assisted treatment in altogether 163 patients (147 male; 16 female; mean age 36.8 years) with high-grade acromioclavicular separation (Rockwood type III: n = 60; Rockwood type IV: n = 6; Rockwood type V: n = 97). RESULTS: Acromioclavicular separation occurred less often in women than men (1:9). In patients under 35, the most common cause for ACJ dislocation was sporting activity (37.4%). Rockwood type V was observed significantly more often than the other types with 57.5% (Rockwood type III = 36.8%, Rockwood type IV 3.7%). Concomitant pathologies were diagnosed in 39.3% of the patients with that number rising to as much as 57.3% in patients above 35 years. Most common associated injuries were rotator cuff injuries (32.3%), chondral defects (30.6%) and SLAP-lesions (22.6%). Of all patients, 8.6% needed additional reconstructive surgery. CONCLUSION: Glenohumeral injuries are a much more common epiphenomenon during acromioclavicular separation than previously ascertained. High risk group for accompanying injuries are patients above 35 years with preexisting degenerative disease. The increasing use of minimally invasive techniques allows for an easier diagnosis and simultaneous treatment of the additional pathologies.


Assuntos
Articulação Acromioclavicular/lesões , Lesões do Ombro/complicações , Adulto , Feminino , Alemanha/epidemiologia , Humanos , Masculino , Estudos Retrospectivos , Lesões do Ombro/epidemiologia , Lesões do Ombro/cirurgia
7.
Arch Orthop Trauma Surg ; 136(12): 1741-1752, 2016 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-27704204

RESUMO

INTRODUCTION: No evidence-based guidelines are available to determine the appropriate stem length, and whether or not to cement stems in revision total knee arthroplasty (TKA). Therefore, the objective of this study was to compare stresses and relative movement of cemented and uncemented stems of different lengths using a finite element analysis. MATERIALS AND METHODS: A finite element model was created for a synthetic tibia. Two stem lengths (95 and 160 mm) and two types of fixation (cemented or press fit) of a hinged TKA were examined. The average compressive stress distribution in different regions of interest, as well as implant micromotions, was determined and compared during lunge and squat motor tasks. RESULTS: Both long and short stems in revision TKA lead to high stresses, primarily in the region around the stem tip. The presence of cement reduces the stresses in the bone in every region along the stem. Short stem configurations are less affected by the presence of cement than the long stem configuration. Press-fit stems showed higher micromotions compared to cemented stems. CONCLUSIONS: Lowest stresses and micromotion were found for long cemented stems. Cementless stems showed more micromotion and increased stress levels especially at the level of the stem tip, which may explain the clinical phenomenon of stem-end pain following revision knee arthroplasty. These findings will help the surgeon with optimal individual implant choice.


Assuntos
Artroplastia do Joelho/métodos , Cimentos Ósseos , Imageamento Tridimensional/métodos , Prótese do Joelho , Tíbia/diagnóstico por imagem , Tomografia Computadorizada por Raios X/métodos , Análise de Elementos Finitos , Humanos , Desenho de Prótese , Reoperação , Tíbia/cirurgia
8.
BMC Musculoskelet Disord ; 15: 369, 2014 Nov 06.
Artigo em Inglês | MEDLINE | ID: mdl-25373872

RESUMO

BACKGROUND: The aim of this cadaveric study was to compare a polyaxial (NCB®, Zimmer) to a fixed-angle monoaxial locking plate (PERILOC®, Smith & Nephew) in comminuted fractures of the distal femur regarding stability of the construct. Up to date there is no published biomechanical data concerning polyaxial plating in cadaveric distal femurs. METHODS: Fourteen formalin fixed femora were scanned by dual-energy x-ray absorptiometry. As fracture model an unstable supracondylar comminuted fracture was simulated. Fractures were pairwise randomly fixed either with a mono- (group A) or a polyaxial (group B) distal femur plate. The samples were tested in a servohydraulic mechanical testing system starting with an axial loading of 200 N following an increase of 200 N in every step with 500 cycles in every sequence up to a maximum of 2 000 N. The end points were implant failure or relevant loss of reduction. Data records included for each specimen time, number of cycles, axial load and axial displacement. Statistical analysis was performed using the exact Wilcoxon signed rank test. RESULTS: The mean donor age at the time of death was 75 years. The bone mass density (BMD) of the femurs in both groups was comparable and showed no statistically significant differences. Five bones failed before reaching the maximum applied force of 2000 N. Distribution curves of all samples in both groups, showing the plastic deformation in relation to the axial force, showed no statistically significant differences. CONCLUSIONS: Operative stabilization of distal femur fractures can be successfully and equally well achieved using either a monoaxial or a polyaxial locking plate. Polyaxial screw fixation may have advantages if intramedullary implants are present.


Assuntos
Placas Ósseas/normas , Fraturas do Fêmur/patologia , Fraturas do Fêmur/terapia , Fixação Interna de Fraturas/normas , Idoso , Idoso de 80 Anos ou mais , Fenômenos Biomecânicos , Feminino , Fraturas do Fêmur/fisiopatologia , Fixação Interna de Fraturas/métodos , Humanos , Masculino , Pessoa de Meia-Idade
9.
Spine J ; 14(12): 2897-904, 2014 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-24768733

RESUMO

BACKGROUND CONTEXT: Thoracolumbar extension-distraction fractures are rare injuries mainly restricted to patients suffering from ankylosing spinal disorders. The most appropriate surgical treatment of these unstable spinal injuries remains to be clarified. PURPOSE: To report on a cohort of 10 patients treated with closed reduction and percutaneous dorsal instrumentation. STUDY DESIGN: Case series. PATIENT SAMPLE: Ten consecutive patients with ankylosing spinal disorders and thoracolumbar extension-distraction fractures (Type B3 according to the AOSpine Thoracolumbar Spine Injury Classification System). OUTCOME MEASURES: Postoperative reduction, alignment, and implant position were analyzed by computed tomography. Loss of reduction was assessed on lateral radiographs by using the Cobb technique. Ambulation ability and pain were assessed at follow-up. METHODS: Minimally invasive dorsal percutaneous instrumentation was performed in 10 consecutive patients (3 men, 7 women) with a mean age of 81.5 (range 72-90) years between May 2010 and December 2012. The mean postoperative follow-up time was 7.9 (range 4-28) months. RESULTS: All 10 patients were treated with closed reduction and dorsal instrumentation; in no case was conversion to an open approach required. The mean operation time was 60.2 (range 32-135) minutes. None of the patients presented neurologic deficits. Cement-augmented screws were implanted in two cases. Sufficient radiographic correction was achieved in all patients; no case of loss of reduction was noted at final follow-up. In one case, complete hardware removal was performed 9 months after the index operation because of persistent back pain at the level of the implant. One patient died of postoperative inferior vena cava obstruction. At discharge, all patients were able to ambulate without the need for crutches or opioid analgesics. At final follow-up, all patients ambulated with full weight bearing; four patients reported persistent back pain. CONCLUSIONS: In fragile patients with ankylosing spinal disorders and thoracolumbar extension-distraction fractures, closed reduction and percutaneous dorsal instrumentation provide a satisfying midterm functional outcome while minimizing perioperative risks compared with conventional dorsoventral procedures.


Assuntos
Fixação Interna de Fraturas/métodos , Fraturas da Coluna Vertebral/cirurgia , Espondilite Anquilosante/cirurgia , Idoso , Idoso de 80 Anos ou mais , Parafusos Ósseos , Feminino , Fixação Interna de Fraturas/efeitos adversos , Fixação Interna de Fraturas/instrumentação , Humanos , Vértebras Lombares/lesões , Masculino , Fraturas da Coluna Vertebral/complicações , Espondilite Anquilosante/complicações , Vértebras Torácicas/lesões
10.
Indian J Orthop ; 47(5): 454-8, 2013 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-24133304

RESUMO

BACKGROUND: Some in vitro studies warn combining different metals in orthopedic surgery. The aim of this study is to determine the impact of combining titanium and stainless steel on bone healing and the clinical course of patients undergoing internal fixation of femoral fractures. MATERIALS AND METHODS: 69 patients with femoral fractures had polyaxial locking plate osteosynthesis. The locking plate was made of a titanium alloy. Two different cohorts were defined: (a) sole plating and (b) additional stainless steel cerclage wiring. Postoperative radiographs and clinical followup were performed at 6 weeks, 3 months and 12 months. RESULTS: Cohorts A and B had 36 and 33 patients, respectively. Patient demographics and comorbidities were similar in both groups. In two cases in cohort A, surgical revision was necessary. No complication could be attributed to the combination of titanium and stainless steel. CONCLUSION: The combination of stainless steel cerclage wires and titanium plates does not compromise fracture healing or the postoperative clinical course.

11.
BMC Musculoskelet Disord ; 14: 72, 2013 Feb 26.
Artigo em Inglês | MEDLINE | ID: mdl-23442604

RESUMO

BACKGROUND: Assessment of shoulder mobility is essential for diagnosis and clinical follow-up of shoulder diseases. Only a few highly sophisticated instruments for objective measurements of shoulder mobility are available. The recently introduced DynaPort MiniMod TriGyro ShoulderTest-System (DP) was validated earlier in laboratory trials. We aimed to assess the precision (repeatability) and agreement of this instrument in human subjects, as compared to the conventional goniometer. METHODS: The DP is a small, light-weight, three-dimensional gyroscope that can be fixed on the distal upper arm, recording shoulder abduction, flexion, and rotation. Twenty-one subjects (42 shoulders) were included for analysis. Two subsequent assessments of the same subject with a 30-minute delay in testing of each shoulder were performed with the DP in two directions (flexion and abduction), and simultaneously correlated with the measurements of a conventional goniometer. All assessments were performed by one observer. Repeatability for each method was determined and compared as the statistical variance between two repeated measurements. Agreement was illustrated by Bland-Altman-Plots with 95% limits of agreement. Statistical analysis was performed with a linear mixed regression model. Variance for repeated measurements by the same method was also estimated and compared with the likelihood-ratio test. RESULTS: Evaluation of abduction showed significantly better repeatability for the DP compared to the conventional goniometer (error variance: DP = 0.89, goniometer = 8.58, p = 0.025). No significant differences were found for flexion (DP = 1.52, goniometer = 5.94, p = 0.09). Agreement assessment was performed for flexion for mean differences of 0.27° with 95% limit of agreement ranging from -7.97° to 8.51°. For abduction, the mean differences were 1.19° with a 95% limit of agreement ranging from -9.07° to 11.46°. CONCLUSION: In summary, DP demonstrated a high precision even higher than the conventional goniometer. Agreement between both methods is acceptable, with possible deviations of up to greater than 10°. Therefore, static measurements with DP are more precise than conventional goniometer measurements. These results are promising for routine clinical use of the DP.


Assuntos
Artrometria Articular/instrumentação , Artrometria Articular/normas , Ombro/fisiologia , Adulto , Artrometria Articular/métodos , Calibragem/normas , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Amplitude de Movimento Articular/fisiologia , Reprodutibilidade dos Testes , Adulto Jovem
12.
Acta Orthop Belg ; 77(5): 616-21, 2011 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-22187836

RESUMO

The purpose of the present study was to evaluate the precision of digital templating in total hip arthroplasty (THA) and the influence of the surgeons' level of experience on the accuracy of preoperative planning. A retrospective review of digital computer planned THA's was performed on 169 hips. The preoperatively planned component sizes were compared to the sizes used in the operation. An exact agreement between planned and actually used size was achieved in 33.7% of the hips for the acetabular cups and 36% for the femoral stems. A prediction of +/- 1 size was reached in 77.5% for acetabular components and 82.3% for the femoral stem. On average, the acetabular components were planned approximately 0.9 sizes too large, the femoral stems 0.3 sizes too small. The accuracy of preoperative planning showed no differences according to the level of training of the planning surgeon. We state that the digital templating is useful to predict the implant size. However, 15 of the 169 planned components showed a difference of more than 2 sizes. Therefore, digital templating cannot fully replace intraoperative X-ray use.


Assuntos
Artroplastia de Quadril , Prótese de Quadril , Ajuste de Prótese , Cirurgia Assistida por Computador , Idoso , Feminino , Humanos , Masculino , Cuidados Pré-Operatórios
13.
BMC Musculoskelet Disord ; 12: 168, 2011 Jul 21.
Artigo em Inglês | MEDLINE | ID: mdl-21777447

RESUMO

BACKGROUND: Assessment of shoulder mobility is essential for clinical follow-up of shoulder treatment. Only a few high sophisticated instruments for objective measurements of shoulder mobility are available. The interobserver dependency of conventional goniometer measurements is high. In the 1990s an isokinetic measuring system of BIODEX Inc. was introduced, which is a very complex but valid instrument. Since 2008 a new user-friendly system called DynaPort MiniMod TriGyro ShoulderTest-System (DP) is available. Aim of this study is the validation of this measuring instrument using the BIODEX-System. METHODS: The BIODEX is a computerized robotic dynamometer used for isokinetic testing and training of athletes. Because of its size the system needs to be installed in a separated room. The DP is a small, light-weighted three-dimensional gyroscope that is fixed on the distal upper patient arm, recording abduction, flexion and rotation. For direct comparison we fixed the DP on the lever arm of the BIODEX. The accuracy of measurement was determined at different positions, angles and distances from the centre of rotation (COR) as well as different velocities in a radius between 0° - 180° in steps of 20°. All measurements were repeated 10 times. As satisfactory accuracy a difference between both systems below 5° was defined. The statistical analysis was performed with a linear regression model. RESULTS: The evaluation shows very high accuracy of measurements. The maximum average deviation is below 2.1°. For a small range of motion the DP is slightly underestimating comparing the BIODEX, whereas for higher angles increasing positive differences are observed. The distance to the COR as well as the position of the DP on the lever arm have no significant influence. Concerning different motion speeds significant but not relevant influence is detected. Unfortunately device related effects are observed, leading to differences between repeated measurements with any two different devices up to 8° at maximal range of motion (180°). CONCLUSIONS: In summary the results shows high correlation and good reproducibility of measurements. All deviations are inside the tolerance interval of 5°, if one device is used. An unlikely systematic device effect is detected. These laboratory trials are promising for the validation of this system in humans. The challenge for both systems will be the changing of the COR in the shoulder joint at elevations higher than 90°.


Assuntos
Artrometria Articular/instrumentação , Artrometria Articular/métodos , Dinamômetro de Força Muscular/normas , Amplitude de Movimento Articular/fisiologia , Síndrome de Colisão do Ombro/diagnóstico , Artrometria Articular/normas , Humanos , Síndrome de Colisão do Ombro/fisiopatologia , Articulação do Ombro/fisiopatologia
14.
BMC Musculoskelet Disord ; 11: 283, 2010 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-21159196

RESUMO

BACKGROUND: Primary stability of cartilage repair constructs is of the utmost importance in the clinical setting but few continuous passive motion (CPM) models are available. Our study aimed to establish a novel ex vivo CPM animal model and to evaluate the required motion cycles for testing the mechanical properties of a new cell-free collagen type I gel plug (CaReS®-1S). METHODS: A novel ex vivo CPM device was developed. Full-thickness cartilage defects (11 mm diameter by 6 mm deep) were created on the medial femoral condyle of porcine knee specimens. CaReS®-1S was implanted in 16 animals and each knee underwent continuous passive motion. After 0, 2000, 4000, 6000, and 8000 motions, standardized digital pictures of the grafts were taken, focusing on the worn surfaces. The percentage of worn surface on the total CaReS®-1S surface was evaluated with image processing software. RESULTS: Significant differences in the worn surface were recorded between 0 and 2000 motion cycles (p < 0.0001). After 2000 motion cycles, there was no significant difference. No total delamination of CaReS®-1S with an empty defect site was recorded. CONCLUSION: The ex vivo CPM animal model is appropriate in investigating CaReS®-1S durability under continuous passive motion. 2000 motion cycles appear adequate to assess the primary stability of type I collagen gels used to repair focal chondral defects.


Assuntos
Colágeno Tipo I , Géis , Articulação do Joelho/fisiologia , Modelos Animais , Terapia Passiva Contínua de Movimento/métodos , Amplitude de Movimento Articular/fisiologia , Animais , Fenômenos Biomecânicos , Doenças das Cartilagens/terapia , Modelos Biológicos , Terapia Passiva Contínua de Movimento/instrumentação , Suínos , Engenharia Tecidual/instrumentação , Engenharia Tecidual/métodos
15.
BMC Musculoskelet Disord ; 11: 82, 2010 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-20433761

RESUMO

BACKGROUND: In the present biomechanical study, the torsional stability of different interference screws, made of bovine bone, was tested. Interference screws derived from bovine bone are a possible biological alternative to conventional metallic or bioabsorbable polymer interference screws. METHODS: In the first part of the study we compared the torsional stability of self-made 8 mm Interference screws (BC) and a commercial 8 mm interference screw (Tutofix). Furthermore, we compared the torsional strength of BC screws with different diameters. For screwing in, a hexagon head and an octagon head were tested. Maximum breaking torques in polymethyl methacrylate resin were recorded by means of an electronic torque screw driver. In the second part of the study the tibial part of a bone-patellar tendon-bone graft was fixed in porcine test specimens using an 8 mm BC screw and the maximum insertion torques were recorded. Each interference screw type was tested 5 times. RESULTS: There was no statistically significant difference between the different 8 mm interference screws (p = 0.121). Pairwise comparisons did not reveal statistically significant differences, either. It was demonstrated for the BC screws, that a larger screw diameter significantly leads to higher torsional stability (p = 9.779 x 10(-5)). Pairwise comparisons showed a significantly lower torsional stability for the 7 mm BC screw than for the 8 mm BC screw (p = 0.0079) and the 9 mm BC screw (p = 0.0079). Statistically significant differences between the 8 mm and the 9 mm BC screw could not be found (p = 0.15). During screwing into the tibial graft channel of the porcine specimens, insertion torques between 0.5 Nm and 3.2 Nm were recorded. In one case the hexagon head of a BC screw broke off during the last turn. CONCLUSIONS: The BC screws show comparable torsional stability to Tutofix interference screws. As expected the torsional strength of the screws increases significantly with the diameter. The safety and in vivo performance of products derived from xenogeneic bone should be the focus of further investigations.


Assuntos
Parafusos Ósseos/normas , Substitutos Ósseos/normas , Transplante Ósseo/instrumentação , Teste de Materiais/métodos , Animais , Ligamento Cruzado Anterior/cirurgia , Fenômenos Biomecânicos , Substitutos Ósseos/uso terapêutico , Transplante Ósseo/métodos , Bovinos , Análise de Falha de Equipamento/métodos , Ligamento Patelar/fisiologia , Ligamento Patelar/transplante , Polimetil Metacrilato/normas , Esterilização/métodos , Estresse Mecânico , Sus scrofa , Torque , Transplante Heterólogo/instrumentação , Transplante Heterólogo/métodos , Suporte de Carga/fisiologia
16.
Arch Orthop Trauma Surg ; 130(8): 993-9, 2010 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-20066430

RESUMO

INTRODUCTION: The application of interference screws for the fixation of bone-patellar tendon-bone (BPTB) grafts is a well-established technique in anterior-cruciate ligament reconstruction. Interference screws derived from bovine compact bone are a biological alternative to metallic or biodegradable polymer interference screws. MATERIALS AND METHODS: In 60 porcine specimens, the tibial part of an anterior-cruciate ligament reconstruction was performed using a BPTB graft. To secure the graft, either an 8-mm titanium interference screw or a self-made bovine interference screw (BC), or a commercial bovine compact bone screw (Tutofix) was used. The maximum failure load was determined by means of a universal testing machine with computer interface at a testing speed of 50 mm/min. In a second test series, cyclic sub-maximal load was applied to the test specimen from 40 to 400 N with a number of 1,000 load cycles and a frequency of 1 Hz. Subsequently, the maximum failure load was determined. The stiffness of the test specimen was investigated in both test series. Each type of interference screw was tested 10 times. RESULTS: A secure fixation of the grafts was achieved with all interference screws. In the experiments on the maximum load to failures, the titanium screws showed significantly higher failure loads than the Tutofix screws (P = 0.005). The stiffness of the grafts fixed with BC screws was significantly higher as compared to the fixation with Tutofix screws (P = 0.005). After cyclic sub-maximal loading, the maximum failure load of the titanium screws was significantly higher than that of the Tutofix screws (P = 0.033). The fixation of the BC screws showed a significantly higher failure load (P = 0.021) and stiffness (P = 0.032) than the Tutofix screw fixation. Except for two screw head fractures and two intra-tendinous graft ruptures, the failure mode was slippage in the interface between interference screw and bone plug. CONCLUSION: Interference screws derived from bovine compact bone show similar good results as the titanium interference screws. Therefore, the safety and in vivo performance of products derived from xenogenic bone should be the focus of further investigations.


Assuntos
Lesões do Ligamento Cruzado Anterior , Parafusos Ósseos , Enxerto Osso-Tendão Patelar-Osso/métodos , Implantes Absorvíveis , Animais , Ligamento Cruzado Anterior/cirurgia , Fenômenos Biomecânicos , Enxerto Osso-Tendão Patelar-Osso/instrumentação , Desenho de Equipamento , Análise de Falha de Equipamento , Suínos , Titânio
17.
J Med Case Rep ; 3: 7071, 2009 Apr 29.
Artigo em Inglês | MEDLINE | ID: mdl-19830134

RESUMO

INTRODUCTION: The combination of neurofibromatosis and liposarcoma is very rare. We present a case of a dedifferentiated liposarcoma in the forearm, as a complication in a patient with neurofibromatosis type 1. CASE PRESENTATION: A Caucasian man with neurofibromatosis type 1 presented at our clinic complaining of a slow growing swelling on his left forearm over a period of one and a half years. Clinical examination and history pointed to malignancy. Radiological examination inclusive of magnetic resonance imaging and positron emission tomography confirmed our suspicion. A final diagnosis of dedifferentiated high-grade liposarcoma with axillary lymph node metastases was established after a pathological examination of a tumour biopsy. The consulting tumour board recommended either an elbow exarticulation or an accurate radical local resection including the metastatic axillary lymph nodes. Fortunately, we were able to perform an R-zero resection and the forearm could be saved. The treatment was completed with postoperative radiotherapy of the left forearm's operative bed, the left axillary and the supraclavicular regions. The patient decided against adjuvant chemotherapy. CONCLUSION: Liposarcoma complicating neurofibromatosis type 1 is a very rare combination. Up to now, only five cases have been reported in the literature. We are adding a new case to this short list to stress the importance of early recognition. It is the first known case with this disease combination in an upper extremity. Liposarcoma is usually treated by surgery followed by radiotherapy. The role of chemotherapy is controversial and should be based on a decision made on a case-by-case basis.

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