The effects of hallux valgus and walking speed on dynamic balance in older adults

BackgroundHallux valgus (HV) contributes to deficits in static balance and increased fall risk in older adults. Very limited research has examined dynamic balance deficits in walking in this population. These individuals generally walk slowly, as balance challenge is lesser at slow speeds.Research questionHow does the dynamic balance of older adults with HV differ from healthy controls at controlled slow and fast walking speeds?MethodsNineteen older adults with HV and 13 healthy controls completed 5 continuous walking trials at 1.0 and 1.3 m·s⁻¹ as whole body marker position and ground reaction force data were captured. Dynamic balance was evaluated using whole body center of mass (COM) and center of pressure (COP) inclination angles (IA) and duration of double support.ResultsThere were no differences in measures of dynamic balance between older adults with and without HV at slow and fast speeds. At the faster speed, the peak sagittal plane COM-COP IA increased and the double support duration decreased, while the peak frontal plane COM-COP IA were not affected.SignificanceOlder adults with HV do not exhibit deficits in dynamic balance during continuous walking at comfortable speeds when compared to healthy older adults.     

多层螺旋CT和MRI测量肩胛盂斜倾角的互补性初探

目的 探讨多层螺旋CT(MSCT)多平面重组(MPR)及MRI测量肩胛盂斜倾角的互补性.方法 收集成人肩胛骨干标本22侧及肩关节防腐湿标本24侧,用16层螺旋CT扫描仪扫描,多平面重组重建肩胛骨并测量肩胛盂斜倾角,得数据A组.收集MRI检查正常的肩关节病例50侧,取其斜冠状位T1WI显示肩锁关节的层面测量肩胛盂斜倾角,得数据B组.进行统计学处理.结果 肩胛盂斜倾角最小值91.10°,最大值118.50°,A、B 2组肩胛盂斜倾角数据分别为101.14°±4.66°和104.05°±7.72°.2种测量方法肩胛盂斜倾角值统计学上有显著性差异(P＜0.05).结论 MSCT的MPR法测量肩胛盂斜倾角与MRI测量值不同,前者略小于后者;MSCT和MRI 2种测量肩胛盂斜倾角方法结合具有重要的应用价值.     

Limb segment inclination sense in proprioception

Summary Two experiments were performed to determine if proprioceptive signals are perceived more readily in terms of limb segment inclinations to the vertical than as joint angles. Subjects attempted to match arm positions with the upper arms supported at different inclinations. Constant error data showed that, when instructed to match forearm inclinations to the vertical, subjects were very accurate. When required to match elbow joint angles, however, errors were strongly biased in the direction of matching forearm inclinations. The results support a view of proprioception as a system in which afferent signals related to the gravitational torques acting at joints lead to the perception of limb orientation rather than joint angles. Such a system would allow more efficient determination of the relationship of limb segments to external objects than would one based purely on joint angles.This work was supported in part by research awards from the U.S. Public Health Service, AG05154, NS17421 and NATO no 227/82     

Are Portable Imaging Intraoperative Radiographs Helpful for Assessing Adequate Acetabular Cup Positioning in Total Hip Arthroplasty?

Despite advances in surgical techniques and instrumentation, current intra-operative estimations of acetabular version in total hip arthroplasty are of limited accuracy. In the present study, two experienced orthopedic surgeons compared intra-operatively measured (using portable imaging) anteversions and vertical inclinations of acetabular components with those measured using standardized radiographs post-operatively in 40 patients. Of the all vertical inclinations measured from intra-operative radiographs, 72.5% (n=29) were within ±2°, and 97.5% (n=39) were within ±5° of those determined using post-operative radiographs, and for anteversion, 52.5% (n=21) were within ±2°, and 97.5% (n=39) were within ±5°. Post-operative radiographs demonstrated that 90.0% (n=36) of vertical inclinations and anteversions were within the adequate zone. Obviously, our method has its limitations, but the authors conclude that the method described in this article better allows surgeons to verify acetabular version intra-operatively. In particular, the described method is suitable in cases with a deformed acetabular anatomy and difficult revision surgery.     

武汉市社区就诊患者双向转诊意愿比较以及影响因素分析

目的：了解社区患者对双向转诊的意愿及影响因素,为有关部门制定促进双向转诊的制度和措施提供科学依据。方法：通过非随机抽样,对武汉市社区卫生服务机构患者进行问卷调查。结果：协议模式60％的患者愿意转诊;托管模式60．5％的患者愿意转诊;院办院管模式51．4％患者愿意转诊。三种模式间患者对双向转诊过程中的下转意愿无显著性差异。托管模式的患者的下转意愿的影响因素较多,包括性别、文化、职业、收入。院办院管模式的患者下转意愿的影响因素包括文化、职业、收入。结论：性别、文化是托管模式下患者的转诊意愿的关键影响因素。     

Effect of the inclination of a maxillary central incisor on periodontal stress: Finite element analysis

Objective:To determine the effect of labiolingual inclination of a maxillary central incisor on the magnitude and distribution of stresses within the periodontal space.Materials and Methods:Five three-dimensional finite element models of a right maxillary central incisor were created with 0°, 10°, 20°, 30°, and 40° inclination. Each incisor model was subjected to a 1 N lingual-directed force and 6–12 N·mm countertipping moment on the labial surface. The stress level within the periodontal ligament was calculated in terms of maximum principal stresses.Results:With increased inclination, compressive stresses tended to increase whereas tensile stresses tended to decrease. The location where compressive stress was prevalent changed from the midroot area to the apical area on the lingual side, while the area where tensile stresses were predominant changed from the midroot area to the cervical area on the labial side.Conclusion:There are more compressive stresses concentrated at the apex of incisors with a high degree of inclination than in incisors that are more upright. This may be associated with the higher clinical incidence of apical root resorption found in inclined maxillary central incisors.     

Buccolingual inclination of molars in untreated children and adults: A cone beam computed tomography study

Objectives:To evaluate and compare the buccolingual inclinations of maxillary and mandibular first molars in untreated children and adults.Materials and Methods:One hundred and thirty-eight subjects were selected and divided into three groups, as follows: (1) age 6–9 years, N = 46; (2) age 10–19 years, N = 56; and (3) age 25–35 years, N = 36. For each subject, existing cone beam computed tomography images were used, and the long axis for each maxillary and mandibular first molar was determined. The converge angles formed by the long axis of left and right maxillary first molars and by the long axis of left and right mandibular first molars were measured.Results:The maxillary molars exhibited buccal inclination, with the converge angle of 21.1° ± 9.5° in group 1, 17.3° ± 8.6° in group 2, and 9.3° ± 7.3° in group 3. Statistically significant differences were found between groups 1 and 3 and groups 2 and 3, but not between groups 1 and 2. The mandibular molars exhibited lingual inclination, with the converge angle of 34.9° ± 11° for group 1, 26.6° ± 9.2° for group 2, and 26.1° ± 7.7° for group 3. Statistically significant differences were found between groups 1 and 2 and groups 1 and 3, but not between groups 2 and 3.Conclusions:Maxillary first molars exhibited buccal inclination. Adults displayed less inclination than did children. Mandibular first molars exhibited lingual inclination. Adults displayed less inclination than did children. Some degree of curve of Wilson should be maintained at the end of orthodontic treatment to fulfill physiologic needs and stability.     

Dissociation of the Harris-Galante II polyethylene liner in rheumatoid arthritis patients

Abstract We investigated the dissociation of polyethylene liner from the Harris-Galante II metal shell inarthritis patients with rheumatoid arthritis. A total of 41 total hip arthroplasties using Harris-Galante II cup in 34 patients were reviewed retrospectively. There were three cases with dissociation of the polyethylene liner and locking tine breakage of metal shell, and one case with locking tine breakage without dissociation of the polyethylene liner. In three cases with dissociation of the polyethylene liner, two cups had been placed relatively horizontally while the third had been placed relatively vertically. In general, high activity, heavy body weight, and young age are thought to be risk factors for polyethylene liner dissociation, but these patients generally have lower activity and lighter body weight compared to patients with osteoarthritis or avascular necrosis of the femoral head. The use of small femoral heads and either horizontal or vertical cup placement may have allowed impingement and tine damage, contributing to liner dissociation in these relatively inactive patients.     

3-D High-Frequency Ultrasound Improves the Estimation of Surface Properties in Degenerated Cartilage

High-frequency ultrasound (US) surface parameters are well known to be sensitive to degenerative changes in cartilage tissue, but estimates deteriorate if the sample is inclined. We propose 3-D US to precisely estimate the local surface and inclination. For this purpose, the most common ultrasonic surface parameters ultrasound roughness index and integrated reflection coefficient were extended to 2-D surface measurements. Tissue-mimicking phantoms and human cartilage samples with varying degrees of degeneration were measured using a 40-MHz transducer. Characteristic inclination dependencies of the parameters aided in the distinction between specular reflected or backscattered signal origins and allowed a restriction to suitable local inclinations. In the application to cartilage, comparisons with histologic grading (structural Mankin-score) depicted a statistically significant (p < 0.05) increase of US roughness index for scores larger than 0 and decrease of integrated reflection coefficient for scores larger than 1. The presented findings will increase the reliability of ultrasonic surface parameters and can in principal be applied in vivo.