Mismatch between Conventional Femoral Arthroplasty Stems and Hip Morphology in the Elderly Chinese Hip Fracture Population

@#Introduction: The morphology of the proximal femur differs in various populations. Based on our clinical experience, conventional femoral stems used in hip arthroplasty do not fit the Chinese population well. Hence, this study aims to evaluate the suitability of conventional femoral stems in the elderly Chinese hip fracture population requiring hip arthroplasty and to establish if gender and age related differences exist within this population. Materials and methods: We retrospectively analysed radiographic data of 300 patients from a tertiary hospital’s geriatric hip fracture database who underwent either hip hemi-arthroplasties or total hip arthroplasties. Proximal femur morphological measurements were recorded, analysed and compared to that of commonly used femoral stems. Subgroup analysis was performed to compare age and gender related differences. Results: A total of 18.3% of the study population had a medial femoral offset (MFO) of less than 30mm, which is the smallest available offset for the implants studied. 22.6% of female and 3% of male subjects had MFOs that were less than 30mm. In our subgroup analysis, males had significantly larger femoral head diameters, MFO and vertical femoral offsets compared to females. Older subjects (75-90 years old) had significantly smaller femoral head diameters, vertical femoral offsets and neck shaft angles compared to younger subjects (60-75 years old). Conclusion: Commonly used femoral stem implants have measurements that do not suit our Chinese population with small medial femoral offsets. In addition, elderly males have significantly larger femoral head diameters, medial and vertical femoral offsets whereas older subjects have significantly smaller femoral head diameters, vertical femoral offsets and neck shaft angles.

A comparative study on the measurement of pupillary offset by Pentacam anterior segment analyzer and Keratron Scout corneal topographer / 国际眼科杂志(Guoji Yanke Zazhi)

@#AIM: To evaluate the difference and consistency of pupillary offset measured by the Pentacam anterior segment analyzer and Keratron Scout corneal topographer.<p>METHODS: Three hundred and eleven patients(604 eyes)who underwent excimer laser in situ keratomileusis from November 2017 to February 2018 were randomly selected. Before surgery, the pupillary offset values were measured by Pentacam and Keratron, and the differences and consistency of the values between the two instruments were compared.<p>RESULTS: The pupillary offset values of the right eyes, left eyes, and both eyes between Pentacam and Keratron were statistically different(<i>P</i><0.05). There were no significant statistical differences in the offset orientations of right eyes, left eyes and both eyes between the two instruments(<i>P</i>>0.05). The 95% consistent line(<i>LoA</i>)of offset value and offset orientation in the right eyes, left eyes and both eyes between the two instruments were -0.11-0.19mm and -157.01°-135.35°, -0.12-0.18mm and -150.16°-158.22°, -0.11-0.19mm and -154.30°-147.10°, respectively. <p>CONCLUSION: The pupillary offset measured by the Pentacam was smaller than that measured by the Keratron, but the difference was within the clinically acceptable range. The accurate pupillary offset can be obtained, and be the mutual reference, correction and supplement in the both instruments.

A verification study of Offset values of different applicators in afterloading brachytherapy / 中华放射肿瘤学杂志

Objective To investigate the Offset values of different applicators in afterloading brachytherapy.Methods Six types of applicators were selected in this study which included stainless steel interstitial needle (Part#083.062),proguide round needle (Part#189.608),proguide sharp needle (Part# 189.601),vaginal multi-channel applicator (Part # 110.800),fletcher CT/MR applicator (Part # 189.745)and henschke titanium applicator (Part#110.437).According to the sources imaging in the fluorography film,the distance of applicators between the first dwell position and the top could be measured.Marker was pasted on the surface of applicator corresponding to the first dwell position.And then the applicator was put into the pelvic phantom for a CT scan.During applicator reconstruction in the treatment planning system,the Offset values of all applicators could be acquired through adjusting the value of offset to superimpose the first dwell and the marker images.On account of the density of plastic material applicators were similar to human tissues,it was difficult to reconstruct the top of the applicator.With the help of stopper or simulation source,the value of offset could be acquired for plastic material applicators.Based on the measurement results,the differences were analyzed among different applicators.Results The Offset values significantly differed among various applicators.The Offset value for stainless steel interstitial needle was-11.4 mm,-4.1 mm for proguide round needle,-3.5 mm for proguide sharp needle,0 mm or-5.0 mm for vaginal multi-channel applicator,-6.5 mm for fletcher CT/MR applicator and-7.5 mm for henschke titanium applicator,respectively.Conclusion To adapt to the rapid development of precise radiotherapy,it is necessary to verify the Offset value in afterloading brachytherapy.

A verification study of Offset values of different applicators in afterloading brachytherapy / 中华放射肿瘤学杂志

Objective@#To investigate the Offset values of different applicators in afterloading brachytherapy.@*Methods@#Six types of applicators were selected in this study which included stainless steel interstitial needle (Part#083.062), proguide round needle (Part#189.608), proguide sharp needle (Part#189.601), vaginal multi-channel applicator (Part#110.800), fletcher CT/MR applicator (Part#189.745) and henschke titanium applicator (Part#110.437). According to the sources imaging in the fluorography film, the distance of applicators between the first dwell position and the top could be measured. Marker was pasted on the surface of applicator corresponding to the first dwell position. And then the applicator was put into the pelvic phantom for a CT scan. During applicator reconstruction in the treatment planning system, the Offset values of all applicators could be acquired through adjusting the value of offset to superimpose the first dwell and the marker images. On account of the density of plastic material applicators were similar to human tissues, it was difficult to reconstruct the top of the applicator. With the help of stopper or simulation source, the value of offset could be acquired for plastic material applicators. Based on the measurement results, the differences were analyzed among different applicators.@*Results@#The Offset values significantly differed among various applicators. The Offset value for stainless steel interstitial needle was -11.4 mm, -4.1 mm for proguide round needle, -3.5 mm for proguide sharp needle, 0 mm or -5.0 mm for vaginal multi-channel applicator, -6.5 mm for fletcher CT/MR applicator and -7.5 mm for henschke titanium applicator, respectively.@*Conclusion@#To adapt to the rapid development of precise radiotherapy, it is necessary to verify the Offset value in afterloading brachytherapy.

Offset femoral en los resultados clínicos y funcionales de los pacientes / Femoral offset in the clinical and functional results of patients; Le déport fémoral dans les résultats cliniques et fonctionnels des patients

Introducción: La restauración de las fuerzas biomecánicas a través del ajuste del offset y la longitud de miembros se ha convertido en un objetivo importante cuando el cirujano busca un buen resultado funcional postoperatorio. Sin embargo, las ventajas clínicas de la restauración del offset femoral y las complicaciones del fallo en la restauración no han sido claramente establecidas. Objetivo: Evaluar el efecto del offset o voladizo femoral en los resultados clínicos y funcionales de los pacientes. Adquisición de la evidencia: Se realizó una exploración en la base de datos Pubmed, con las palabras clave: artroplastia de cadera, prótesis de cadera, resultado clínico y resultado funcional.Se buscaron artículos publicados entre 2008 y 2018, basados en humanos y escritos en inglés, español o francés. Se seleccionaron seis artículos que incluían la presencia de una medición radiológica del offset femoral claramente explicada, escalas validadas y análisis comparativo. Resultados: La literatura consultada reflejó resultados heterogéneos. En el grupo de pacientes con offset disminuido, un artículo mostró menos función. En otro estudio se observó mejor puntuación en el grupo de enfermos con offset aumentado. A su vez, en una investigación se comprobó menos dolor en el grupo de offset disminuido. Conclusiones: Debido a la inconsistencia en los resultados y en las metodologías empleadas, no ha sido posible reconocer el beneficio clínico y funcional de la restauración del offset. Algunos autores incluidos en esta revisión, después de no encontrar diferencias estadísticamente significativas, afirmaron que la restauración o el aumento del offset femoral aportó buenos resultados, sin efectos negativos(AU)

Introduction: The restoration of biomechanical forces through offset adjustment and limb length has become an important objective when the surgeon seeks a good postoperative functional result. However, the clinical advantages of femoral offset restoration and complications of restoration failure have not been clearly established. Objective: To evaluate the effect of offset or femoral cantilever on the clinical and functional results of the patients. Acquisition of evidence: An exploration was carried out in the Pubmed database, with the keywords: hip arthroplasty, hip prosthesis, clinical result and functional result. We searched for articles published from 2008 to 2018, based on humans and written in English, Spanish or French. Six articles were selected because they clearly explained the presence of a radiological measurement of the femoral offset, including validated scales and comparative analysis. Results: The literature consulted reflected heterogeneous results. In the group of patients with decreased offset, one article showed less function. In another study, a better score was observed in the group of patients with increased offset. In turn, one investigation reported less pain was found in the reduced offset group. Conclusions: Due to the inconsistency in the results and the methodologies used, it has not been possible to recognize the clinical and functional benefit of offset restoration. Some authors included in this review, after not finding statistically significant differences, stated that the restoration or increase of the femoral offset provided good results, without negative effects(AU)

Outcome evaluation of the drug withdrawl mode as used at inpatient pharmacy / 中华医院管理杂志

Drug withdrawal has always been a tough challenge in drug quality management for the pharmacist. In order to optimize the drug withdrawal process, the hospital has introduced an inpatient pharmacy IT system. This system can efficiently minimize the drug withdrawal rate of major departments and withdrawal counts due to substandard quality problems, thus sizably avoiding human resource wastes in the conventional withdrawal process, reducing drug quality problem, enhancing management efficiency and efficiency of nursing staff and pharmacists, and ensuring clinical drug use safety.

Application of detector array in treatment planning system modeling adjustment / 中华放射肿瘤学杂志

Objective To investigate the feasibility of detector array in Monaco modeling for MLC parameters adjustment.Methods One parameter was fixed, and then the other parameter was changed.The γ pass rates of the test beams, namely 3ABUT, 7SegA, and FOUR L, were assessed to determine the values of leaf transmission and leaf offset.A total of 12 tumor cases from different anatomical sites were randomly selected.Two-dimensional dose verification (rack angle zero) of Step& Shot and dMLC plans as well as three-dimensional dose validation of VMAT plan were performed using Octavius 4D system.The γ pass rates were analyzed at a standard of 3%/3 mm.Meanwhile, the point dose verification for these three plans was analyzed to obtain the dose deviations.Results The values of leaf transmission and leaf offset were 0.0105 and-0.08 mm, respectively.The average γ pass rates (%) of Step& Shot, dMLC, and VMAT plans were 88.59±2.94, 87.81±3.28, and 87.45±2.24 before adjustment and 98.45±1.23, 98.9±1.01, and 96.03±1.66 after adjustment.In addition, the average dose deviations (%) according to the point dose verification were 0.85±0.75, 0.95±0.39, and 0.98±0.40 before adjustment and 0.97±0.57, 1.08±0.76, and 0.86±0.45 after adjustment.Conclusions Octavius detector 729 ionization chamber array is a feasible and reliable device in Monaco modeling for MLC parameters adjustment.

To analyze the performances and the related measurement values for femoro-acetabular impingement on MSCT / 实用放射学杂志

Objective To investigate the performances and characteristics of femoro-acetabular impingement (FAI)on MSCT. Methods Hips jointed MSCT scans of 109 cases (as case group)and the other 120 cases (as control group)were analyzed retrospec-tively,to analyze the anatomy and osseous abnomality of FAI.Alpha angle,offset,CE angle were measured.The data were tested by using t test and ANOVA test.Results There were 57 cases of osseous protuberance at the femoral head and neck joint,26 cases of the offset reduction,17 cases of over-coverage acetabulum,41 cases of over-deep acetabulum,20 cases of acetabular retroversion,57 cases of subcortical cystic degeneration at the femoral head and neck joint and 22 cases of subchondral cystic degeneration at the ace-tabulum margin.Significant statistical differences were found between case group and control group in alpha angle value,offset and CE angle (P<0.05).Multiple comparisons demonstrated that except results between the value of alpha angle of Cam-type and Mixed-type(P=0.071),Pincer-type and the control group(P=0.083)with no statistical significance,the differences between any other two groups reached statistical significance (P<0.05).Multiple comparisons demonstrated that except result between the value of offset of Cam-type and Mixed-type(P=0.561)with no statistical significance,the differences between any other two groups reached statistical significance (P<0.05).Multiple comparisons demonstrate that except results between the value of CE angle Pin-cer-type and Mixed-type (P=0.444),Cam-type and the control group (P=0.236)with no statistical significance,the differences be-tween any other two groups reached statistical significance (P<0.05).Conclusion Different type of FAI has its unique anatomical features.Alpha angle,offsetand CE angle for the diagnosis of FAI have important reference values.

Cementless Total Hip Arthroplasty Using Dual Offset Titanium Tapered Stem: At Least 7-Year Follow-Up / 대한정형외과학회잡지

PURPOSE: The purpose of current study is to evaluate the midterm results of cementless primary total hip arthroplasty (THA) using a dual offset titanium tapered stem. MATERIALS AND METHODS: A retrospective analysis of 102 cases (84 patients), with a minimum of 7-year clinical follow-up, was performed. All of the cases consisted of patients who underwent primary cementless THA, using a dual offset titanium tapered stem in The Catholic University of Korea, Bucheon St. Mary's Hospital between July 2004 and May 2009. Clinical results were analyzed via the Harris hip score, level of thigh pain, squeaking around hip joint, and complication rate. Radiologic results were examined with stability and location of inserted prosthesis, hypertrophy of femoral cortex, and osteolysis. RESULTS: Out of the 102 cases (84 patients; 47 males and 37 females), with the mean age of 55.9 years (range, 27–79 years) and mean follow-up period of 99.2 months (range, 84–132 months). The mean Harris hip score was 53.8 preoperatively (range, 26–75) and improved to 93.5 postoperatively (range, 74–100) (p=0.000). All of the cases gained stable bony fixation on the final follow-up, including 2 cases of intra-operative proximal femur fracture. Calcar remodeling was observed in 94 cases, however, they were irrelevant with stem stability. Cortical hypertrophy of femur was seen in 12 cases and thigh pain in 4 cases; nonetheless, they were not relevant (p=0.067). There was 1 case of squeaking sound during joint movement. Hip dislocation occurred in 1 case early after the procedure, but the event was due to excessive anteversion of the acetabular cup, in which a revisional replacement procedure of the acetabular cup was conducted. No sign of ceramic breakage was observed. There were 2 cases of heterotrophic ossification. CONCLUSION: Results from a 7-year follow-up of cementless THA using dual offset titanium tapered stem were encouraging in both clinical and radiologic evaluations.

Quantification of Patellar Maltracking Combined with J-Sign Using Computed Tomography / 中国运动医学杂志

Objective To quantify the patellar mal-tracking combined with J-sign using the computed tomography (CT).Method Fifty-three adult patients diagnosed as recurrent patellar dislocation (RPD) were chosen.According to their patellar tracking during knee active flexion and extension,they were divided into group A(with positive J-sign) and group B(with negative J-sign).The CT examinations were performed in all patients at 0°extension of the knee and the patella bisect offset index (BOI),patella troehlear-groove distance (PTG) and patella lateral tilt (PLT) were measured in the axial position and compared.The receiver operating characteristic analysis (ROC) curve was used to analyse the accuracy and stability of the three J-sign parameters.Results In all the 53 patients,thirty-seven(69.8％) knees were of positive J-sign,while the rest 16 were of negative J-sign.The mean values of CT parameters BOI,PTG and PLT in group A were significantly larger than those of group B.Moreover,the area under the curve for BOI,PTG and PLT were 0.906,0.883 and 0.833 respectively.The sensitivity and specificity of BOI were 83.3％ and 87.5％,while the predicting cut-off value was 97.5％.Conclusion In all the 53 recurrent patella instability patients,the morbidity of patella proximal mal-trackingis 69.8％.The CT parameter BOI can be used to quantify the J-Sign into positive and negative groups.

CLINICAL OBSERVATION OF IMPROVING AXIAL OFFSET BY USING Ilizarov BONE TRANSPORT TECHNOLOGY / 中国修复重建外科杂志

OBJECTIVE: To explore the effectiveness of Ilizarov technique in improving bone transport axial offset. METHODS: Between January 2010 and December 2014, 14 patients with tibial fracture were treated by using Ilizarov technique. Of 14 cases, 11 were male and 3 were female, aged 18-70 years (mean, 38.8 years); there were 10 cases of infective bone defect and 4 cases of non-infective bone defect. According to Paley typing, 7 cases were rated as type B1(bone defect without shortening) and 7 cases as type B3(bone defect with shortening). The injury to operation time was 1 to 72 months (mean, 11.9 months). Ilizarov fixation was used for type architecture and adjusting fixed bone removal of half the distance between the needle and the ring, changing the auadrilateral edges, adjusting the convolution relationship between the bone removal section and bone segment involution, and adjusting the two force lines of bone segment involution end so as to make the limb lines of force satisfactory. RESULTS: The patients were followed up 9-31 months (mean, 19.1 months). Four cases achieved natural bone healing at last follow-up, bone healing was obtained in 10 cases after bone graft. At 1 week after operation, X-ray films showed angulation in the coronal plane in 10 cases (3-12°, 4.9° on average) and in the sagittal plane in 9 cases (2-12°, 3.8° on average); axial offset was observed in 6 cases (43%), which was corrected in 5 cases except 1 case. At last followup, angulation in the coronal plane was observed in 5 cases (2-4°, 2.6° on average), angulation in the sagittal plane in 6 cases (2-6°, 4.1° on average), and axial offset in 1 case (7%), which were significantly improved when compared with ones at 1 week. According to Paley evaluation criteria, the osseous results were excellent in 12 cases and good in 2 cases; the functional results were excellent in 12 cases and good in 2 cases at last follow-up. CONCLUSIONS: Axial offset in the Ilizarov bone transport relatively common. By adjusting fixed bone removal of half the distance between the needle and the ring, the axial offset can be improved.

Changes in Femoral Posterior Condylar Offset, Tibial Posterior Slope Angle, and Joint Line Height after Cruciate-Retaining Total Knee Arthroplasty

PURPOSE: Changes in the femoral posterior condylar offset (PCO), tibial posterior slope angle (PSA), and joint line height (JLH) after cruciate-retaining total knee arthroplasty (CR-TKA) were evaluated to determine their influence on the flexion angle. MATERIALS AND METHODS: A total of 125 CR-TKAs performed on 110 patients were retrospectively reviewed. Pre- and postoperative PCO, PSA, and JLH were compared using correlation analysis. Independent factors affecting the postoperative flexion angle of the knee were analyzed. RESULTS: The PCO was 28.2+/-2.0 mm (range, 24.5 to 33.1 mm) preoperatively and 26.7+/-1.8 mm (range, 22.2 to 31.2 mm) postoperatively (r=0.807, p0.291). CONCLUSIONS: Although the PCO and JLH did not change significantly after CR-TKA, the PSA decreased by 5.5degrees with a small range of variation. Restoration of the PCO and JLH could promote optimization of knee flexion in spite of the decreased PSA after CR-TKA.

Revisiones de cadera en defectos óseos femorales Paprosky II y IIIA. Utilización de prótesis no cementada, modular, de fijación proximal y anclaje distal / Revision total hip arthroplasty in Paprosky II and IIIA femoral bone defects. Use of modular uncemented stems with proximal fixation

Introducción: El objetivo de este estudio retrospectivo fue observar el comportamiento de un tallo modular de fijación proximal y anclaje distal en revisiones de cadera con defectos femorales II y IIIA (Paprosky), evaluando la estabilidad protésica y articular, la restauración del offset y la diferencia de longitud. Materiales y Métodos: Se analizaron 22 revisiones de reemplazos totales de cadera. Doce mujeres y 10 hombres (edad promedio 62.38 años). El seguimiento promedio fue de 62 meses. El tallo femoral utilizado fue S-ROM® (Depuy, Johnson & Johnson). Los defectos óseos femorales fueron 15 de tipo II y 7 de tipo IIIA de Paprosky. Para la evaluación clínica se utilizó el puntaje de cadera de Harris. En las radiografías, se analizó el comportamiento del tallo, su integración, la diferencia de longitud y el offset femoral, y se consideró correcta una diferencia <5 mm. Resultados: El offset fue restaurado en 16 (72,3%) casos y la longitud de miembros se restauró en 15 (68,2%). Hubo un solo hundimiento del tallo, y de acuerdo con la clasificación de Engh, se observaron 17 (77,27%) uniones óseas. Se produjeron siete (31,8%) complicaciones, dos luxaciones que requirieron revisión, cuatro fracturas intraoperatorias y una paresia de ciático poplíteo externo. Conclusiones: Este tallo impresiona ser una alternativa válida para resolver un problema complejo. Por su versatilidad, permite resolver mecánicamente el defecto óseo, devuelve la longitud al miembro y el offset a la articulación, con un índice de complicaciones aceptables.

Background: The purpose of this retrospective analysis was to observe the outcomes of a modular hip system in revision total hip arthroplasty with Paprosky types II and IIIA femoral bone defects, evaluating their performance, offset restoration and leg length discrepancy correction. Methods: Twenty-two revision total hip arthroplasties were analyzed in 12 women and 10 men (average age 62.38 years). The average follow-up was 62 months. Femoral stems S-ROM® (Depuy, Johnson & Johnson) were used. Paprosky femoral bone deficit were 15 types II and 7 IIIA. Clinical evaluation was performed using the Harris Hip Score, while Engh lassification was used for stem fixation. Offset restoration, leg length discrepancy (a difference <5 mm was considered correct) and hip stability were evaluated radiographically. Results: Offset was properly restored in 16 (72.3%) cases and the leg length was matched in 15 (68.2%). There was a single stem subsidence and according to Engh classification, proximal bone ingrowth fixation was obtained in 17 (77.27%) patients. There were 7 (31.8%) complications: two dislocations that required revision, four intraoperative fractures and a lateral popliteal nerve paresis. Conclusions: S-ROM® modular system seems to be a valid alternative to solve a complex problem. Its versatility allows to optimize hip stability, leg length equalization and offset restoration in revision total hip arthroplasty, showing an acceptable complication rate.

Proximal Femoral Shortening after Operation with Compression Hip Screws for Intertrochanteric Fracture in Patients under the Age of 60 Years / 대한고관절학회지

PURPOSE: We aimed to quantify proximal femoral shortening after operation with compression hip screws for intertrochanteric fracture in patients under the age of 60 years. MATERIALS AND METHODS: We followed 37 consecutive patients with intertrochanteric fractures treated with compression hip screws from March 2005 to February 2014. We designated the aspect of the fracture, a defect of the postero-medial wall, a defect of the lateral wall, and the degree of reduction as four potentially important factors we assumed would strongly affect proximal femoral shortening. We quantified proximal femoral shortening and compared the effects of above factors. We divided femoral shortening into two plane vectors; femoral offset in the horizontal plane and leg length discrepancy in the vertical plane. We measured shortening separately during two periods: during operation and after weight bearing (called dynamic compression). RESULTS: After bone union, the average femoral offset shortening was 5.45 mm. Patient groups with anatomic reduction and intact postero-medial wall showed lower femoral offset shortening than the respective opposite groups. As to functional score using modified Harris hip score, low femoral offset shortening group showed more 2.35 scores than high groups. None of the factors significantly affected leg length shortening. CONCLUSION: We found that a stable medial buttress is involved in lower femoral offset shortening. Thus, surgeons need to attempt to recover the defect of the medial wall and to reduce anatomically when operating intertrochanteric fractures with compression hip screws.

Femoral offset and its relationship to femoral neck-shaft angle and torsion angle / Desplazamiento femoral y su relación con el ángulo cuello-diáfisis femoral y el ángulo de torsión

The aims to study the femoral offset and its relationship to femoral neck-shaft angle and torsion angle. One hundred paired (50 males and 50 females) Chinese femurs were used to measure the femoral offset, femoral neck-shaft angle and torsion angle. The data were analyzed by SPSS software. Femoral offsets were male right 44.40±4.56 mm, left 42.70±4.95 mm; female right 39.90±6.00 mm, left 38.90±6.18 mm. Femoral torsion angles were male right 6.02±10.85°, left 7.08±9.30°; female right 10.02±11.69, ° left 6.02±10.85°. Neck-shaft angles were male right 131.80±4.36°, left 134.00±4.78°; female right 132.10±5.94°, left 132.80±4.93°. There were no sexual differences in the two femoral angles (P>0.05) while there was a significant sexual difference in the femoral offset (P<0.01). The differences between left and right femoral offset and neck-shaft angle were significant (P<0.01). Clinically, our results indicate that FO could be obtained using the regression equation when the torsion angle and/or neck-shaft angle is measured.

El objetivo fue estudiar el desplazamiento femoral y su relación con el ángulo cuello-diáfisis femoral y el ángulo de torsión. Se utilizaron 100 pares de fémures (50 hombres y 50 mujeres) y se tomaron las medidas del desplazamiento femoral, ángulo cuello-diáfisis femoral y ángulo de torsión. Los datos fueron analizados con el software SPSS. El desplazamiento femoral en los hombres fue 44,40±4,56 mm en el lado derecho y 42,70±4,95 mm en el lado izquierdo, y en las mujeres, fue de 39,90±6,00 mm y 38,90±6,18 mm para el lado derecho e izquierdo, respectivamente. El ángulo de torsión femoral del lado derecho en los hombres fue 6,02±10,85° y 7,08±9,30° del izquierdo; mientras que en las mujeres, fue de 10,02±11,69° y 6,02±10,85° para el lado derecho e izquierdo, respectivamente. Los ángulos cuello-diáfisis fueron 131,80±4,36° en el lado derecho, y 134,00±4,78° en el izquierdo, para los hombres, mientras que en las mujeres fueron de 132,10±5,94° en el lado derecho y 132,80±4,93° en el izquierdo. No hubo diferencias según sexo en los dos ángulos femorales (P>0,05), mientras que si hubo una diferencia significativa en el desplazamiento femoral (P<0,01). Las diferencias entre el desplazamiento femoral izquierdo y derecho, y el ángulo cuello-diáfisis fueron significativas (P<0,01). Clínicamente, nuestros resultados indican que el desplazamiento femoral podría obtenerse utilizando la ecuación de regresión cuando se mide el ángulo de torsión o el ángulo cuello-diáfisis.

Instantaneous Position and Orientation of the Body Segments as an Arbitrary Object in 3D Space by Merging Gyroscope and Accelerometer Information / Posición y orientación instantánea de los segmentos corporales como un objeto arbitrario en el espacio 3D a través de la fusión de la información de acelerómetros y giroscopios

This work presents an algorithm to determine instantaneous orientation of an object in 3D space. The orientation was determined by using a Direction Cosine Matrix (DCM), performed by the combination of three consecutive rotations, around each to the main axes of the evaluated system, using quaternions. An inertial measurement unit (IMU), consisting of 3 axes gyroscope and 3 axes accelerometer was used in order to establish 2 coordinate systems; The first one describes object movement, by using gyroscope as a main source of information, relating the angular rate of change along time. The second defines a coordinate reference system, relating the acceleration of gravity to an inertial direction vector. A proportional integral (PI) feedback controller was used, which includes sensors information, eliminating offset, cancelling drift and improving the accuracy of the orientation. The proposed algorithm can be used for assessing both the position and orientation of the body segments which is very important in orthopedic, traumatology and rheumatology important for diagnosis, prognostic, therapeutic, research and as well as the design and fabrication of measuring devices used in surgical instrumentation, prostheses and ortheses. It is important to note that the developed system opens the opportunities to be implemented on ambulatory joint evaluation through a wearable system, due to the dimensions and requirements of the sensors.

El presente trabajo presenta un algoritmo para determinar la orientación instantánea de un objeto en el espacio 3D. La orientación fue determinada utilizando una matriz de cosenos directores (DCM) conformada por la combinación de 3 rotaciones consecutivas alrededor de cada uno de los ejes del sistema evaluado, utilizando cuaterniones. Una unidad inercial de medida (IMU) compuesta por un giroscopio de 3 ejes y un acelerómetro de 3 ejes fue utilizada con el objetivo de establecer 2 sistemas coordenados; Un sistema coordenado describiendo el movimiento del objeto, utilizando al giroscopio como fuente principal de información, estableciendo la relación de cambio con respecto al tiempo. Un sistema coordenado de referencia, relacionando la aceleración gravitacional a un vector inercial. Un control por retroalimentación proporcional integral (PI) fue utilizado con el objetivo de combinar la información de los sensores, eliminando las desviaciones por offset y deriva, mejorando la precisión en la orientación. Dadas sus características, el algoritmo propuesto permite su utilización en la evaluación de la posición y la orientación de los segmentos corporales, siendo de suma importancia en ortopedia, traumatología y reumatología para la determinación de diagnósticos, pronósticos terapéuticos e investigación así como el diseño y fabricación de dispositivos de medición, instrumentación quirúrgica, prótesis y ortesis. Cabe destacar que el sistema desarrollado abre oportunidades de ser implementado en el diseño de sistemas ambulatorios de evaluación de las articulaciones, mediante el uso de elementos transportables dadas las reducidas dimensiones y limitaciones de los sensores empleados.

Effect of Posterior Femoral Condylar Offset and Posterior Tibial Slope on Maximal Flexion Angle of the Knee in Posterior Cruciate Ligament Sacrificing Total Knee Arthroplasty

PURPOSE: To evaluate the effect of femoral condylar offset and posterior tibial slope on maximal flexion angle of the knee in posterior cruciate ligament (PCL)-sacrificing total knee arthroplasty (TKA, Medial-Pivot Knee System). MATERIALS AND METHODS: Forty-five knees in 35 patients who could be followed up more than 1 year after PCL-sacrificing TKA were evaluated retrospectively. We measured and analyzed the preoperative and postoperative maximal flexion angle, posterior femoral condylar offset difference, posterior femoral condylar offset ratio difference, and tibial slope. RESULTS: The mean maximal flexion angle after TKA was 118.44degrees+/-9.8degrees and significantly related to postoperative tibial slope (11.78degrees+/-6.2degrees) in correlation analysis (R=0.451, p=0.002). There was no statistical relationship between the postoperative maximal flexion angle and the posterior femoral condylar offset difference (3.24+/-3.862 mm, R=0.105, p=0.493) and posterior femoral condylar offset ratio difference (0.039+/-0.029 mm, R=-0.163, p=0.284). CONCLUSIONS: The maximal flexion angle of the knee after PCL-sacrificing TKA was significantly related to the postoperative tibial slope. Therefore, posterior tibial slope can be considered as a factor that affects maximal flexion angle after PCL-sacrificing TKA.

Effects of femoral offset on the stress level of total hip arthroplasty in the elderly : a three-dimensional finite element analysis / 中华创伤杂志

Objective To evaluate the effects of femoral offset (FO) on the stress level of bone cement total hip arthroplasty (THA) in the elder patients by the three-dimensional finite element analysis. Methods The normal bilateral hip joints in two cases was determined with CT imaging,with parameters including FO,neck shaft angle and neck length.The three-dimensional finite element model of THA was built so as to make Von Mises stress analysis of the changes of different neck lengths,neck shaft angles and FO. Results Stress levels in the prosthesis and bone cement reduced monotonically with the increase of neck shaft angles.In the meantime,the stress levels were lowered when neck length was in a range of 35-44 mm,but beyond the range they showed monotonous increase. Conclusions The reduction of stress levels of prosthesis and bone cement,promotion of femur stress and extension of range of motion of hip joints are closely related to FO.FO reconstruction benefits the restoration of abductor force arm and biomechanical function of normal hip joints.

Unveiling the uncertainty principle in the QRS complex offset detection on high resolution electrocardiography

The accuracy of high resolution electrocardiographic (HRECG) methods for stratifying the risk of malignant ventricular arrhythmia depends on the fidelity of QRS fiducial points detection. This study aims at examining the effect of acquisition and processing variables in HRECG on the variability of QRS complex offset (QRS offset) detection in simulated and biological signals, as well as investigating the factors related to the so called uncertainty principle applied to HRECG. Successive QRS offset locations were calculated in different signals configurations including HRECG data from patients with and without ventricular late potentials and simulated data using linear and exponential functions. The expected error in QRS offset detection was assessed as a function of: i)   signal characteristics (Simulated or Biological); ii) Sampling Frequency (SF); iii) Residual Noise Level (RNL); iv) QRS maximum amplitudes. The uncertainty principle was related to HRECG and a given exponential signals, and increasing RNL up to  0.5  μV. SF and RNL are outstanding factors influencing QRS offset variability. Thus, HRECG related uncertainty principle is a deterministic phenomenon associated with both HRECG signal and mathematical formulation of the terminal decay of the QRS complex to the fusion with the ST segment.

A precisão dos resultados dos exames de eletrocardiografia de alta resolução (ECGAR) para estratificação do desenvolvimento de arritmias ventriculares malignas depende da fidelidade na detecção dos pontos fiduciais do complexo QRS. O presente estudo tem o objetivo de avaliar o efeito das variáveis de aquisição e processamento do ECGAR sobre a variabilidade da detecção do ponto final do complexo QRS (QRS-fim) em sinais biológicos simulados e reais, bem como investigar o efeito de condições relacionadas ao assim formulado “princípio da incerteza da eletrocardiografia de alta resolução”. Detecções sucessivas do QRS-fim foram realizadas usando diferentes configurações de sinais simulados e de pacientes com e sem potenciais tardios ventriculares. Os sinais simulados empregaram funções lineares e exponenciais para mimetização da porção final do complexo QRS. O erro de detecção do QRS-fim esperado foi avaliado em função de: i) procedência dos sinais (simulado ou biológico); ii) frequência de amostragem (FA); iii) nível de ruído residual (NRR); iv) amplitude máxima do complexo QRS. A presença do princípio da incerteza relacionou-se ao padrão de decaimento exponencial e ao aumento progressivo da NRR, até  0,5  μV. FA e NRR têm impacto significativo na variabilidade do QRS-fim. Assim, o principio da incerteza da ECGAR é um fenômeno determinístico dependente da forma de onda relativa ao decaimento da região terminal do complexo QRS até a sua fusão com o segmento ST.

Effect of femoral offset on hip joint function reconstruction after arthroplasty in femoral neck fractures / 中华创伤骨科杂志

Objective To study the effect of femoral offset reconstruction ON the Harris hip score and the hip ROM (range of motion) after artificial hip replacement in femoral neck fractures. Methods Follow-ups were conducted for 47 patients who had undergone artificial hip replacements for their unilateral femoral neck fractures. We took X-ray pictures to compare the femoral offsets at the affected and unaffected hips. The operated hips were evaluated by the Harris hip score. Statistical analyses were performed with SPSS l2.0 software. Results The Harris hip score of the operated hip was positively related to femoral offset reconstruction(t=7.25,P＜0.001).There was a significant and positive correlation between femoral offset and the hip abductor ROM(r=0.80,P＜0.001).The rate of femoral offset reconstruction had no significant difference between total hip arthroplasty and bipolar hip arthroplasty (χ2=0,P＞0.05).Conclusions Reconstruction of femoral offset after artificial hip replacement in the femoral neck fractures can improve funetional recovery and ROM of the hip. Femoral offset reconstruction is uncorrelated to the selection of total hip arthroplasty or bipolar hip arthroplasty.