Pronation on weightbearing radiographs does not correlate with pronation from weightbearing CT scans

IntroductionIn hallux valgus (HV), first metatarsal pronation is increasingly recognized as an important aspect of the deformity. The purpose of this study was to compare pronation in HV patients determined from the shape of the lateral head of the first metatarsal on AP weightbearing radiographs with pronation calculated from weightbearing CT (WBCT) scans.MethodsPatients were included in this study if they had preoperative and 5-month postoperative WBCT scans and corresponding weightbearing AP radiographs of the affected foot. Pronation of the first metatarsal on WBCT scans was measured using a 3D CAD model and the alpha angle and categorized into four groups on radiographs. Association between pronation groups on radiographs and WBCT scans was determined using Spearman correlation coefficients (r_s) and by comparing mean WBCT pronation of the first metatarsal between plain radiograph pronation groups.ResultsAgreement between the two observers’ pronation on radiographs was good (k = 0.634) and moderate (k = 0.501), respectively. There was no correlation between radiographic pronation and the 3D CAD model (r_s < 0.15). Preoperatively, there was weak correlation between the alpha angle and the radiographic pronation groups (r_s = 0.371, P = 0.048) although this relationship did not hold postoperatively (r_s = 0.330, P = 0.081). There was no difference in mean pronation calculated on WBCT scans between the plain radiographic groups.ConclusionPronation of the first metatarsal measured on weightbearing AP radiographs had moderate interobserver agreement and was only weakly associated with pronation measured from WBCT scans. These results suggest that first metatarsal pronation measured on weightbearing radiographs is not a substitute for pronation measured on WBCT scans.Level of evidenceIII, retrospective cohort study.     

Foot disorders in the elderly: A mini-review

Ageing process is associated with changes to the aspect, biomechanics, structure and function of the foot, it may be related with a marked presence of foot conditions, pain, disability and other overall health problems that constitute a major public health concern.Also, the prevalence of epidemiologic research found an incidence of foot problems which is even higher as a consequence of increasing life expectation. Several studies have also suggested that such foot disorders currently affect between 71 and 87% of older patients and are a frequent cause of medical and foot care.Thus, these kind problems are extremely common conditions in the general population, especially in the elderly who are associated with poor quality of life, balance impairment, increase the risk of falls, dificulty on putting shoes, fractures, restrict mobility and performance of activities of daily living that turn can produce serious physical, mental and social consequences in the older people.The role of the physician in the assessment, evaluation, and examination of foot problems is very important, yet it is often an overlooked and undervalued component of geriatric health care.The purpose of this article is to review and to provide an overview of the most common foot deformities precipitating factors, clinical presentation, evidence-based diagnostic evaluation, and treatment recommendations with a view to preventing medical conditions or deformities affecting the feet that may alter foot condition and general health amongst the elderly.     

老年性拇外翻的治疗

目的探讨老年性拇外翻的治疗方法。方法自2003年10月至2007年10月期间用第一跖趾关节融合术共治疗拇外翻足21例,患者年龄60-81岁,平均（66.13±6.8）岁。术前拇外翻角度平均47.0±5.4度,第一、二跖骨间夹角平均16.3±4.7度,术前按美国足踝外科拇趾跖趾关节-趾间关节评分标准评定,平均26.4±4.5分。全部病人均采用跖趾关节内侧切口,修整关节面后用二枚直径3.0mm空心钉固定。结果术后拇外翻角度平均16±6.5度,较术前平均减小29.3±3.5度（P〈0.01）;第一、二跖骨间夹角平均9.5±4.7度,较术前平均减小7.4±2.5度（P〈0.01）。术后按美国足踝外科拇趾跖趾-趾间关节评分标准评定,平均87.9±5.1分,平均提高65.1±4.7分（P〈0.01）。结论第一跖趾关节融合术可有效地治疗年龄大、畸形严重、骨质疏松以及跖趾关节骨关节炎的拇外翻。     

Relationship between lower limb EMG activity and knee frontal plane projection angle during a single-legged drop jump

ObjectivesTo assess a relationship between lower limb muscle activity and the frontal plane knee kinematics during a single-legged drop jump.DesignCorrelation study;SettingFunctional Anatomy Laboratory.Participants35 healthy collegiate male athletes.Main outcome measuresMuscle activity (%MVIC) of gluteus maximus, gluteus medius, biceps femoris, semitendinosus, vastus medialis quadriceps, vastus lateralis quadriceps, medial gastrocnemius and lateral gastrocnemius; peak knee frontal plane projection angle; and Pearson's correlation coefficients between muscle activity and peak knee frontal plane projection angle. All outcomes were assessed for both dominant and non-dominant limbs.ResultsSignificant correlations (r = 0.46–0.60, P < 0.05) were found between the muscle activities of the gluteus maximus, gluteus medius, biceps femoris, and semitendinosus, when compared to the knee frontal plane projection angle.ConclusionGluteal muscles and hamstring muscles are associated with the peak knee frontal plane projection angle during a single-legged drop jump test. Thus, gluteal and hamstring muscle activities should be considered when developing rehabilitation or injury prevention programs.     

基于CT和MRI膝关节有限元模型建立与不同载荷下生物力学特性分析

基于CT和MRI图像数据建立膝关节有限元模型,采用六面体网格对不同载荷系统下人体膝关节生物力学特性进行研究,并进行有效性验证。建立膝关节有限元模型包括:股骨、胫骨、髌骨、腓骨、股骨软骨、胫骨软骨、腓骨软骨、半月板、前后交叉韧带、内外侧副韧带、髌韧带和股四头肌腱等。对膝关节施加1 kN轴向压缩载荷、134 N后向抽屉力和5、10、15 N[?m内翻力矩和外翻力矩,分析膝关节内软骨和半月板的接触应力和接触面积,股骨内外翻倾角以及位移变化情况。在1 kN压缩载荷和134 N抽屉力作用下,股骨软骨、内外侧半月板和内外侧胫骨软骨的接触应力峰值分别为4.47、3.25、2.83、2.70、2.53 MPa,Von Mises应力峰值分别为2.22、2.44、2.25、2.07、1.64 MPa。股骨相对胫骨前向位移为4.19 mm。施加5、10、15 N[?m内翻和外翻力矩时,股骨内翻和外翻倾角分别为3.49°、4.48°、4.91°和3.22°、3.62°、4.01°。随着力矩的线性增大,膝关节各组成部分的应力呈非线性变化趋势。膝关节软骨、半月板和韧带的研究结果符合其生物力学特性,与前人数值分析和实验研究结果相一致,可为临床膝关节生理病理分析和治疗提供一定的理论依据。