不同坐姿对背部形态与臀压的影响

目的 探讨不同坐姿对脊柱和骨盆代偿特征的影响,为寻找出一个理想的坐姿姿势提供理论依据,减少不良坐姿给人体带来的姿势代偿。 方法 使用 Diers formetric 及 Pedscan 模块进行 20 名健康青年直立坐、跷腿坐、盘腿坐坐姿下表面形态学参数和臀压参数测量。 结果 相对直立坐姿,跷腿坐导致骨盆后倾、侧倾和相对扭转 (P<0. 05),跷腿侧臀压面积减少(P<0. 05),最大压力和平均压力显著增加(P<0. 05)。 双臀最大压力比、平均压力比(P<0. 05)及臀压面积(P<0. 05)的对称性降低;相对直立坐姿,盘腿坐姿下矢状面偏移角度增加(P<0. 05),躯干前屈、腰椎后凸(P<0. 05)的同时伴随骨盆后倾(P<0. 05),臀压面积减少(P<0. 05)。 结论 3 种坐姿中,直立坐姿下臀两侧受力均匀,背部表形态学参数最优,腰椎和骨盆代偿最少,可认为是理想的坐姿。     

Factors that influence soft tissue thickness over the greater trochanter: Application to understanding hip fractures

Fall‐related hip injuries are a concern for the growing population of older adults. Evidence suggests that soft tissue overlying the greater trochanter attenuates the forces transmitted to the proximal femur during an impact, reducing mechanical risk of hip fracture. However, there is limited information about the factors that influence trochanteric soft tissue thickness. The current study used ultrasonography and electromyography to determine whether trochanteric soft tissue thickness could be quantified reproducibly and whether it was influenced by: (1) gender; (2) hip postures associated with potential falling configurations in the sagittal plane (from 30° of extension to 60° of flexion, at 15° intervals), combined adduction‐flexion, and combined adduction‐extension; and (3) activation levels of the tensor fascia lata (TFL) and gluteus medius (GM) muscles. Our results demonstrated that soft tissue thickness can be measured reliably in nine hip postures and three muscle activation conditions (for all conditions, ICC >0.98). Mean (SD) thickness in quiet stance was 2.52 cm. Thickness was 27.0% lower for males than females during quiet stance. It was 16.4% greater at maximum flexion than quiet standing, 27.2% greater at maximum extension, and 12.5% greater during combined adduction‐flexion. However, there was no significant difference between combined adduction‐extension and quiet standing. Thickness was not affected by changes in muscle activity. Forces applied to the femoral neck during a lateral fall decrease as trochanteric soft tissue thickness increases; gender and postural configuration at impact could influence the loads applied to the proximal femur (and thus hip fracture risk) during falls on the hip. Clin. Anat. 28:253–261, 2015. © 2014 Wiley Periodicals, Inc.     

Non-linear flexion relationships of the knee with the hip and ankle, and their relative postures during landing

The knee joint, together with the hip and ankle, contributes to overall shock absorption through their respective flexion motions during landing. This study sought to investigate the presence of a lower extremity coordination pattern by determining mathematical relationships that associate knee flexion angles with hip flexion and ankle dorsiflexion angles during landing phase, and to determine relative postures of the hip and ankle, with reference to the knee, and examine how these relative postures change during key events of the landing phase. Eight healthy male subjects were recruited to perform double-leg landing from 0.6-m height. Motion capture system and force-plates were used to obtain kinematics and ground reaction forces (GRF) respectively. Non-linear regression analysis was employed to determine appropriate mathematical relationships of the hip flexion and ankle dorsiflexion angles with knee flexion angles during the landing phase. Relative lower extremity postures were compared between events of initial contact, peak GRF and maximum knee flexion, using ANOVA on ranks. Our results demonstrated a lower extremity coordination pattern, whereby the knee flexion angles had strong exponential (R² = 0.92–0.99, p < 0.001) and natural logarithmic (R² = 0.85–0.97, p < 0.001) relationships with hip flexion and ankle dorsiflexion angles respectively during the landing phase. Furthermore, we found that the subjects adopted distinctly different relative lower extremity postures (p < 0.05) during peak GRF as compared to initial contact. These relative postures were further maintained till the end of the landing phase. The occurrence of these relative postures may be a reflexive mechanism for the subjects to efficiently absorb the impact imposed by the peak GRF.     

Whole-body hypothermia has central and peripheral influences on elbow flexor performance

The superimposed twitch technique was used to study the effect of whole-body hypothermia on maximal voluntary activation of elbow flexors. Seven subjects [26.4 ± 4 years old (mean ± SD)] were exposed to 60 min of either immersion in 8°C water (hypothermia) or sitting in 22°C air (control). Voluntary activation was assessed during brief (3 s) maximal voluntary contractions (MVCs) and then during a 2 min fatiguing sustained MVC. Hypothermia (core temperature 34.8 ± 0.9°C) decreased maximal voluntary torque from 98.2 ± 1.0 to 82.8 ± 5.8% MVC (P < 0.001) and increased central conduction time from 7.9 ± 0.4 to 9.1 ± 0.7 ms (P < 0.05). Hypothermia also decreased maximal resting twitch amplitude from 17.6 ± 4.0 to 10.0 ± 1.7% MVC (P < 0.005) and increased the time-to-peak twitch tension from 55.4 ± 4.0 to 79.0 ± 11.7 ms (P < 0.001). During the 2 min contraction, hypothermia decreased initial torque (P < 0.01) but attenuated the subsequent rate of torque decline (control from 95.5 ± 4 to 29.4 ± 8% MVC; and hypothermia from 85.3 ± 8 to 37.3 ± 5% MVC; P < 0.01). Cortical superimposed twitches increased as fatigue developed but were always lower in the hypothermic conditions. Cortical superimposed twitches increased from a value of 0.4 ± 0.3% MVC prefatigue to 3.9 ± 1.4% MVC postfatigue (P < 0.001) in the hypothermic conditions and from 1.7 ± 0.9 to 5.5 ± 2.3% MVC in control conditions. Our results suggest that hypothermia decreases MVCs primarily via peripheral mechanisms and attenuates the rate of fatigue development by reducing central fatigue.     

Risk factors for a pressure-related deep tissue injury: a theoretical model

Pressure-related deep tissue injury is the term recommended by the United States National Pressure Ulcer Advisory Panel to describe a potentially life-threatening form of pressure ulcers, characterized by the presence of necrotic tissue under intact skin, and associated with prolonged compression of muscle tissue under bony prominences. In this study, a theoretical model was used to determine the relative contributions of the backrest inclination angle during prolonged wheelchair sitting, the muscle tissue stiffness and curvature of the ischial tuberosities (ITs) to the risk for injury in the gluteus muscles that pad the IT bones during sitting. The model is based on Hertz’s theory for analysis of contact pressures between a rigid half-sphere (bone) and an elastic half-space (muscle). Hertz’s theory is coupled with an injury threshold and damage law for muscle—both obtained in previous studies in rats. The simulation outputs the time-dependent bone–muscle contact pressures and the injured area in the gluteus. We calculated the full-size (asymptotic) injured area in the gluteus and the time for injury onset for different sitting angles α( (90–150°), muscle tissue long-term shear moduli G (250–1,200 Pa) and bone diameters D (8–18 mm). We then evaluated the sensitivity of model results to variations in these parameters, in order to determine how injury predictions are affected. In reclined sitting (α = 150°) the full-size injured area was ∼2.1-fold smaller and the time for injury onset was ∼1.3-fold longer compared with erect sitting (α = 90°). For greater G the full-size injured area was smaller but the time for injury onset was shorter, e.g., increasing G from 250 to 1200 Pa decreased the full-size injured area ∼2.5-fold, but shortened the time for injury onset 6.2-fold. For smaller D the time for injury onset dropped, e.g., decreased ∼1.5-fold when D decreased from 18 to 8 mm. Interestingly, the full-size injured area maximized at D of about 12 mm but decreased for smaller or larger D. The susceptibility to sitting-acquired deep tissue injury strongly depends on the geometrical and biomechanical characteristics of the bone–muscle interface, and, particularly, on the radius of curvature of the IT which mostly influenced the size of the wound, and on the muscle stiffness which dominantly affected the time for injury onset.     

Modulation of flexion reflex induced by hip angle changes in human spinal cord injury

The flexion reflex can be elicited via stimulation of skin, muscle, and high-threshold afferents inducing a generalized flexion of the limb. In spinalized animal models this reflex is quite prominent and is strongly modulated by actions of hip proprioceptors. However, analogous actions on the flexion reflex in spinal cord injured (SCI) humans have not yet been examined. In this study, we investigated the effects of imposed static hip angle changes on the flexion reflex in ten motor incomplete SCI subjects when input from plantar cutaneous mechanoreceptors was also present. Flexion reflexes were elicited by low-intensity stimulation of the sural nerve at the lateral malleolus, and were recorded from the ipsilateral tibialis anterior (TA) muscle. Plantar skin stimulation was delivered through two surface electrodes placed on the metatarsals, and was initiated at different delays ranging from 3 to 90 ms. We found that non-noxious sural nerve stimulation induced two types of flexion reflexes in the TA muscle, an early, and a late response. The first was observed only in three subjects and even in these subjects, it appeared irregularly. In contrast, the second (late) flexion reflex was present uniformly in all ten subjects and was significantly modulated during hip angle changes. Flexion reflexes recorded with hip positioned at different angles were compared to the associated control reflexes recorded with hip flexed at 10°. Hip flexion (30°, 40°) depressed the late flexion reflex, while no significant effects were observed with the hip set in neutral angle (0°). Strong facilitatory effects on the late flexion reflex were observed with the hip extended to 10°. Moreover, the effects of plantar skin stimulation on the flexion reflex were also found to depend on the hip angle. The results suggest that hip proprioceptors and plantar cutaneous mechanoreceptors strongly modulate flexion reflex pathways in chronic human SCI, verifying that this type of sensory afferent feedback interact with spinal interneuronal circuits that have been considered as forerunners of stepping and locomotion. The sensory consequences of this afferent input should be considered in rehabilitation programs aimed to restore movement and sensorimotor function in these patients.     

Influence of relative humidity on prolonged exercise capacity in a warm environment

This study examined the influence of relative humidity on endurance exercise performance in a warm environment. Eight male volunteers performed four cycle exercise trials at 70% maximum oxygen uptake until volitional exhaustion in an environmental chamber maintained at 30.2 ± 0.2°C. Volunteers were tested under four relative humidity (rh) conditions: 24, 40, 60 and 80%. Core and weighted mean skin temperature, heart rate, skin blood flow, and cutaneous vascular conductance were recorded at rest and at regular intervals during exercise. Mean ± SD time to exhaustion was 68 ± 19, 60 ± 17, 54 ± 17, and 46 ± 14 min at 24, 40, 60, and 80% rh, respectively (P < 0.001); exercise time was significantly less at 60% (P = 0.013) and 80% (P = 0.005) rh than recorded at 24% rh. There were no differences in core temperature (P = 0.480) and heart rate (P = 0.097) between trials. Core temperature at exhaustion was 39.0 ± 0.3°C at 24, 40, and 60% rh and 39.1 ± 0.3°C at 80% rh (P = 0.159). Mean skin temperature at the point of exhaustion was higher at 80% rh than at 24% rh (P < 0.001). Total sweat loss was similar between trials (P = 0.345), but sweating rate was higher at 60 and 80% rh than at 24% rh (P < 0.001). The results suggest that exercise capacity at moderate intensity in a warm environment is progressively impaired as the relative humidity increases.     

Local subcutaneous and muscle pain impairs detection of passive movements at the human thumb

Activity in both muscle spindle endings and cutaneous stretch receptors contributes to the sensation of joint movement. The present experiments assessed whether muscle pain and subcutaneous pain distort proprioception in humans. The ability to detect the direction of passive movements at the interphalangeal joint of the thumb was measured when pain was induced experimentally in four sites: the flexor pollicis longus (FPL), the subcutaneous tissue overlying this muscle, the flexor carpi radialis (FCR) muscle and the subcutaneous tissue distal to the metacarpophalangeal joint of thumb. Tests were conducted when pain was at a similar subjective intensity. There was no significant difference in the ability to detect flexion or extension under any painful or non-painful condition. The detection of movement was significantly impaired when pain was induced in the FPL muscle, but pain in the FCR, a nearby muscle that does not act on the thumb, had no effect. Subcutaneous pain also significantly impaired movement detection when initiated in skin overlying the thumb, but not in skin overlying the FPL muscle in the forearm. These findings suggest that while both muscle and skin pain can disturb the detection of the direction of movement, the impairment is site-specific and involves regions and tissues that have a proprioceptive role at the joint. Also, pain induced in FPL did not significantly increase the perceived size of the thumb. Proprioceptive mechanisms signalling perceived body size are less disturbed by a relevant muscle nociceptive input than those subserving movement detection. The results highlight the complex relationship between nociceptive inputs and their influence on proprioception and motor control.     

汉族男性青年志愿者不同体位脊柱-骨盆矢状位参数变化的影像学研究

目的 对比汉族青年男性志愿者站立位、直立坐位和自然坐位X线的脊柱-骨盆矢状位参数差异,评估骨盆旋转对矢状位平衡的影响。方法 采用横断面研究。2017年9—10月,在南京鼓楼医院骨科的研究生中招募志愿者32人,均为汉族男性,年龄23～27(24.8±1.6)岁,身高171～185(176.4±5.3)cm,体质量57.7～88.4(69.5±8.6)kg,体质量指数(BMI)21.2～24.7(22.5±2.3)kg/m²。应用EOS-X线成像系统,采用垂直扫描方式,人体全长影像一次扫描成像,结合常用的拍摄方式进行站立位、直立坐位、自然坐位拍摄。影像学测量参数包括胸椎后凸角(TK)、腰椎前凸角(LL)、骶骨倾斜角(SS)、骨盆入射角(PI)、骨盆倾斜角(PT)以及脊柱的矢状位偏移(SVA)、T₁骨盆角(TPA)。采用配对样本t检验比较不同体位时影像学参数的变化情况,对脊柱-骨盆参数之间关系采用Pearson相关性分析。结果 32名志愿者,站立位时PI、PT、SS、LL、TK、SVA、TPA 分别为49.06°±6.22°、13.38°±6.06°、35.03°±2.32°、-47.16°±7.64°、32.22°±9.74°、(3.29±13.64)mm、9.47°±5.26°,直立坐位时分别为48.22°±6.07°、29.06°±10.35°、18.84°±5.90°、-26.38°±8.45°、31.78°±9.95°、(34.73±13.62)mm、26.06°±8.71°,自然坐位时分别为49.22°±6.20°、40.50°±10.42°、9.84°±4.87°、-4.03°±6.14°、31.69°±9.73°、(63.37±13.70)mm、49.66°±11.22°。与站立位各参数值比较,直立坐位与自然坐位PT、SVA、TPA增加,SS、LL减少;与直立坐位比较,自然坐位PT、SVA、TPA增加,SS、LL减少:差异均有统计学意义(P值均＜0.05)。脊柱-骨盆矢状位参数之间的Pearson相关性分析结果显示:(1)站立位时,PI与PT、LL、TK、TPA呈相关性,PT与LL、TK、TPA呈相关性,LL与TK、TPA呈相关性,TK与TPA呈相关性;(2)直立坐位时,PI与PT、SS、LL、TK、TPA呈相关性,PT与SS、LL、TK、TPA呈相关性,SS与LL、TK、TPA呈相关性,LL与TK、TPA呈相关性,TK与TPA呈相关性;(3)自然坐位时,PI与PT、SS、LL、TK、TPA呈相关性,PT与SS、LL、TK、TPA呈相关性,SS与LL、TK、TPA呈相关性,LL与TK、TPA呈相关性。这些相关性差异均有统计学意义(P值均＜0.05)。结论 正常汉族青年男性从站立位到直立坐位、直立坐位到自然坐位的过程中,LL减小,SVA、TPA显著增大,提示躯干矢状位平衡轴前移、骨盆向后旋转。脊柱参数与骨盆参数存在一定的相关性,骨盆的位置改变可以影响到脊柱的序列与平衡。     

Changes in skin reactivity, specific IgE and IgG levels after one year of immunotherapy in olive pollinosis

Changes in specific skin reactivity, specific IgE and specific IgG after immunotherapy (IT) were investigated in olive pollinosis. Thirty patients, receiving IT with commercial extracts, were studied in comparison with a control group of seven patients, receiving only drug therapy. Skin reactivity, IgE and IgG were assessed before starting IT and 1 year later. Definite changes in the three considered parameters occurred in patients given IT with Olea europaea extracts; no variation was observed in the control group. The specific skin reactivity, evaluated by means of quantitative skin prick tests, significantly decreased (Skin Index geometrical mean from 2.73 to 0.88, P less than 0.001); the specific IgE, measured by RAST, were surprisingly decreased (from 7.76 to 4.74 PRU/ml, P less than 0.001); the specific IgG, measured by ELISA, in basic conditions were detectable only in nine patients of 30, while, after IT, they were found in almost all patients with a remarkable increase (from 5.48 to 266.89 AU/ml, P less than 0.001). No correlation was found among the changes in the considered parameters, suggesting that, at least in olive pollinosis, specific skin reactivity, specific IgE and specific IgG are three variables depending on IT but reciprocally independent.     

The potential of human toe flexor muscles to produce force

The maximal force a muscle produces depends among others on the length of the muscle and therefore on the positions of the joints the muscle crosses. Long and short toe flexor muscles (TFM) cross the ankle joints and metatarsal phalangeal joints (MPJ) and work against gravity during human locomotion. The purpose of this study was to describe the maximal moments around the MPJ during maximal voluntary isometric contractions (MVIC) of the TFM as a function of ankle joint and MPJ position. Twenty men performed MVIC of the TFM in a custom-made dynamometer. Ankle and MPJ angles were modified after each contraction. External moments of force around the MPJ were determined. Moments ranged between 6.3 ± 2.6 Nm and 14.2 ± 5.8 Nm. Highest moments were produced at 0°-10° ankle joint dorsal flexion and 25°-45° MPJ dorsal flexion. Lowest moments were generated at 35° ankle joint plantar flexion and 0° MPJ dorsal flexion. In conclusion, if the ankle is plantar-flexed, dorsal flexion of the MPJ avoids a disadvantage of the force-length relationship of TFM. Therefore, MPJ dorsal flexion is a necessary function in the push-off phase of human locomotion to work against the loss of the mechanical output at the forefoot caused by plantar flexion of the ankle.     

锤状指治疗中固定指位的应用解剖研究

目的 探讨成人新鲜上肢标本指间关节活动对伸肌腱Ⅰ~Ⅱ区伸肌腱的影响,为临床锤状指治疗中固定指位的选择提供解剖学基础。方法 纳入成人新鲜上肢标本16侧,取示、中、环、小指各16指,分别于各指在近侧指间关节0°伸直位、45°屈曲位和90°屈曲位时,测量远侧指间关节的最大被动屈曲角度。显露伸肌腱Ⅰ~Ⅱ区,制作锤状指畸形模型,克氏针在中节指骨颈水平垂直于指骨长轴穿透指骨作为参照,于伸肌腱Ⅱ区上做标记,测量肌腱滑动距离。固定远侧指间关节于0°伸直位,近侧指间关节自0°伸直位至90°屈曲位,观察伸肌腱Ⅱ区断端间隙距离的变化,并测量肌腱的滑动距离。结果 实验显示,当近侧指间关节于90°屈曲位时,远侧指间关节的最大被动屈曲角度较近侧指间关节于0°伸直位时增加约21%;近侧指间关节处于0°伸直位时,示指、中指、环指及小指的伸肌腱Ⅱ区末端断端间隙距离分别为(0.35±0.06)mm、(0.42±0.05)mm、(0.46±0.06)mm、(0.51±0.08)mm;固定远侧指间关节,屈曲近侧指间关节至90°屈曲位时,近侧断端向远侧滑移,示指、中指、环指及小指的滑移距离分别为(0.69±0.09)mm、(0.74±0.03)mm、(0.80±0.07)mm、(0.81±0.10)mm,且最终远近两侧断端重叠。结论当远侧指间关节于轻度过伸位、近侧指间关节于屈曲位时,断端间隙消失,此时伸肌腱Ⅰ~Ⅱ域区松弛,张力降低。在锤状指治疗应用上述指位可降低肌腱张力,利于肌腱愈合。     

Waist‐to‐hip ratio and adipose tissue distribution: Contribution of subcutaneous adiposity

The waist‐to‐hip ratio (WHR) reflects the relative distribution of adipose tissue in the human body. However, whether this is due to the musculoskeletal structures of the waist and hip or the overlying subcutaneous adipose tissue has been disputed. We measured waist and hip girths in 11 male and 11 female cadavers, aged 55–94 years, before and after complete removal of skin and subcutaneous adipose tissue. Girths measured following removal of subcutaneous adipose tissue were termed “waist gx” and “hip gx”, and their ratio “WHRx”. Masses of regional adipose tissue segments were obtained by complete dissection, and the adipose mass ratios “trunk/arm‐plus‐leg”, “trunk/leg”, “internal/arm‐plus‐leg”, and “internal/leg” were derived. As assessed by analysis of variance, WHR accounted for significant (P < 0.05) portions of the variance in all adipose mass ratios; adjustment for internal adipose mass increased the significance of all these relationships (P < 0.005). The ratio WHRx was not related to any ratio of regional adipose masses. Waist girth was related to trunk (P < 0.001) and internal (P < 0.05) adipose masses, and hip girth was related to arm‐plus‐leg adipose mass (P < 0.0001) and leg adipose mass (P < 0.0001), but waist gx and hip gx were not related to dependent variables. The results indicate that the ability of WHR and waist and hip girths to reflect the regional distribution of adipose tissue in the body is dependent upon the subcutaneous adipose tissue mass of the waist hip area, not its musculoskeletal constituency. Am. J. Hum. Biol. 15:428?432, 2003. © 2003 Wiley‐Liss, Inc.     

In vivo lumbar erector spinae oxygenation and blood volume measurements in healthy men during seated whole-body vibration

Exposure to whole-body vibration is implicated as one of the occupational risk factors for lower back disorders; however, its influence on the lumbar muscle physiology is still poorly understood. The objective of this study was to investigate the effects of backrest support and hand grip contractions on lumbar muscle oxygenation and blood volume responses during seated whole-body vibration using continuous dual-wave near-infrared spectroscopy. Thirteen healthy men were exposed to frequencies of 3, 4.5 and 6 Hz on a vibration simulator, in randomized order on separate days. Each day the duration of the protocol was 30 min. During the fifth minute of vibration 'with' and 'without' backrest support, participants performed maximal rhythmic hand grip contractions for 1 min. In general, erector spinae oxygenation and blood volume showed a trend to decrease with vibration exposure compared to the control condition. However, these responses were not influenced by the change in vibration frequency (P > 0.05). Sitting without backrest resulted in a greater decrease in oxygenation (by 27%, P = 0.02) and blood volume (by 11%, P = 0.05) than with backrest, implying a deficiency in oxygen supply owing to the sitting posture. Compared to the vibration-only condition, hand grip work decreased both oxygenation (by 22%, P = 0.003) and blood volume responses (by 13%, P = 0.04), suggesting that postural load due to prolonged sitting combined with physical activity during vibration might further burden paraspinal muscles. The influence of adipose tissue thickness of the lumbar muscle on optically derived oxygenation and blood volume changes was inconclusive.     

SuperPATH微创技术在全髋关节置换术中的应用及近期疗效分析

目的 探讨SuperPATH微创技术在全髋关节置换术(THA)中的应用与近期疗效。方法 回顾性分析2016年6月—2018年3月四川大学华西医院金堂医院骨科行THA的153例(160髋)患者的临床资料和影像资料,其中男79例、女74例,年龄25~86(60.81±10.55)岁。左侧68例,右侧78例,双侧7例。按手术方式不同分为2组,其中采用SuperPATH微创入路(SuperPATH组)69例(72髋),采用传统后外侧入路(传统手术组)84例(88髋)。对比2组患者围术期一般情况、关节功能改善情况、实验室指标、影像学检查结果。结果 两组患者均顺利完成手术。SuperPATH组手术时间、切口长度、术中出血量、术后引流量、C反应蛋白、红细胞沉降量分别为(112.09±21.93)min、(8.45±1.10)cm、(243.18±66.00)mL、(186.36±65.80)mL、(84.07±51.69)mg/L和(46.95±19.58)mm/1h,传统手术组分别为(94.69±13.13)min、(14.69±1.41)cm、(290.38±69.31)mL、(240.38±61.68)mL、(134.72±57.51)mg/L和(64.05±27.17)mm/1h。两组间比较,SuperPATH组手术时间大于传统手术组,而切口长度、术中出血量、术后引流量、C反应蛋白、红细胞沉降率均小于传统手术组,差异均有统计学意义(t=3.636、16.703、2.822、3.069、2.922、2.339, P值均＜0.05)。153例(160髋)患者获得随访,随访时间为6~31个月,平均24个月。随访期间无一例患者出现假体周围骨折、感染、脱位等并发症。末次随访时,所有患者假体均未见松动下沉,未见透亮线及骨溶解发生;SuperPATH组屈髋和髋外展角度分别为118.18°±7.64°和42.95°±3.67°,大于传统手术组的110.77°±10.55°和38.08°±5.49°,差异均有统计学意义(t=3.881、3.022, P值均＜0.05);而VAS、Harris评分、髋臼外展角和前倾角,两组间差异均无统计学意义(P值均＞0.05)。SperPATH组1例(1髋)股骨柄轻度内翻,传统手术组股骨柄均为中立位植入,两组间比较差异无统计学意义(P＞0.05)。结论 与传统手术比较,采用SuperPATH微创入路行THA,尽管手术时间偏长,但可在术后最大限度地保留髋关节周围动力结构,减少手术创伤,增加关节活动度,符合目前髋关节外科微创化发展和加速康复理念的要求。     

Alteration of quadriceps muscle activity during functional step tasks after extended sitting session

BackgroundProlonged sitting with high knee flexion is a common activity that may affect patellofemoral joint compression and quadriceps length. Exploring the quadriceps activation after sitting may help to explain the mechanism underlying muscle changes and the resulting patellofemoral pain.ObjectivesTo examine changes in quadriceps activity after prolonged sitting in cross-legged sitting, side-sitting, and sitting on a chair.DesignLaboratory observational study.MethodThirty healthy women participated and were randomly allocated to three groups of different sitting positions (n = 10/group). Electromyography (EMG) of the vastus medialis (VM), rectus femoris (RF), and vastus lateralis (VL) was performed before and after 15 min after sitting. EMG was conducted during step-up and step-down tests and was reported as %MVIC. The results were analysed using Wilcoxon signed-rank test and Kruskal-Wallis ANOVA.ResultsVM activity and EMG activity during the step-down test after sitting increased significantly in the cross-legged group (p = 0.01). Sitting postures significantly influenced (p = 0.02) muscle activity changes in the VL and VM during the step-up test. Pairwise comparisons revealed significant differences between the cross-legged sitting and sitting on a chair groups.ConclusionsProlonged cross-legged sitting and side-sitting caused changes in VM and VL activity during step tasks in healthy young women. After cross-legged sitting, the VM exhibited a significantly higher activity in descending control, and changes in VM and VL activity increased significantly during the step-up task. Increased VM and VL activation possibly controls the patellofemoral joint. Therefore, they may fatigue more easily when many step tasks or squatting exercises are performed.     

Interstitial glycerol concentrations in human skeletal muscle and adipose tissue during graded exercise

AIM: It is not clear how lipolysis changes in skeletal muscle and adipose tissue during exercise of different intensities. We aimed at estimating this by microdialysis and muscle biopsy techniques. METHODS: Nine healthy, young men were kicking with both legs at 25% of maximal power (Wmax) for 45 min and then simultaneously with one leg at 65% and the other leg at 85% Wmax for 35 min. RESULTS: Glycerol concentrations in skeletal muscle and adipose tissue interstitial fluid and in arterial plasma increased (P<0.001) during low intensity exercise and increased (P<0.05) even more during moderate intensity exercise. The difference between interstitial muscle and arterial plasma water glycerol concentration, which indicates the direction of the glycerol flux, was positive (P<0.05) at rest (21 +/- 9 microM) and during exercise at 25% Wmax (18 +/- 6 microM). The difference decreased (P<0.05) with increasing exercise intensity and was not significantly different from zero during exercise at 65% (-11 +/- 17 microM) and 85% (-12 +/- 13 microM) Wmax. In adipose tissue, the difference between interstitial and arterial plasma water glycerol increased (P<0.001) with increasing intensity. The net triacylglycerol breakdown, measured chemically from the biopsy, did not differ significantly from zero at any exercise intensity although directional changes were similar to microdialysis changes. CONCLUSIONS: Skeletal muscle releases glycerol at rest and at low exercise intensity but not at higher intensities. This can be interpreted as skeletal muscle lipolysis peaking at low exercise intensities but could also indicate that glycerol is taken up in skeletal muscle at a rate which is increasing with exercise intensity.     

Effect of electronic toilet system (bidet) on anorectal pressure in normal healthy volunteers: influence of different types of water stream and temperature

Although bidets are widely used in Korea, its effects on anorectal pressures have not been studied in detail in terms of the water settings used. Twenty healthy volunteers were placed on a toilet equipped with a bidet, and anorectal pressures were measured with a manometry catheter inserted into the rectum and anal canal before and after using the bidet at different water forces (40, 80, 160, 200 mN), temperatures (24°C vs 38°C), and water jet widths (narrow vs wide). The pressure at anal high pressure zone decreased from 96.1 ± 22.5 to 81.9 ± 23.3 mmHg at water jet pressure of 40 mN and 38°C wide water jet (P < 0.001), from 94.3 ± 22.4 to 80.0 ± 24.1 mmHg at water jet pressure of 80 mN and 38°C narrow water jet (P < 0.001), and from 92.3 ± 22.4 to 79.6 ± 24.7 mmHg at a water jet pressure of 80 mN and 38°C wide water jet (P < 0.001). At other settings, no significant changes were observed. Our results indicate that, in addition to cleansing effect, bidet could be used to reduce anal resting pressure in the same manner as the traditional warm sitz bath under the conditions of low or medium water jet pressure, a warm water temperature, and a wide type water jet.     

臀肌挛缩症患者三维步态特征分析

目的：探讨臀肌挛缩症患者步态的功能量化指标为该疾病的诊断提供参考与依据。方法：2011年8月-2011年11月,选取臀肌挛缩症患者16例作为研究组,同期选取健康自愿者16例作为对照组,应用三维步态系统对两组进行三维步态对比分析。结果：①步态周期时间参数：研究组在常速、快速行走时步态周期较对照组明显延长（P〈0．01）,步幅、步速较对照组均明显减小（P〈0．01）。②下肢关节角度特征：与对照组比较,研究组在常速、快速行走时髋关节摆动期最大屈曲角度及研究组快速行走时髋关节屈伸角度变化范围均减小（P〈0．05）;研究组常速、快速行走时膝关节冠状面角度变化范围均增大（P〈0．05）,而膝关节支撑相最大屈曲角度和膝关节屈伸角度范围均减小（P〈0．01）;研究组常速行走时重心左、右位移增大（P〈0．05）,快速行走时重心上、下位移减小（P〈0．05）。结论：应用三维步态分析系统对臀肌挛缩症患者进行功能量化评价,可以更为准确地观察臀肌挛缩症患者步态的生物力学变化,为患者的诊断提供了参考和依据。     

Lengthening but not shortening history of paraspinal muscle spindles in the low back alters their dynamic sensitivity

Proprioception is considered important for maintaining spinal stability and for controlling posture and movement in the low back. Previous studies demonstrate the presence of thixotropic properties in lumbar muscle spindles, wherein a vertebra's positional history alters spindle responsiveness to position and movement. This study investigated whether a vertebra's movement history affects the velocity sensitivity of paraspinal muscle spindles in the low back. Afferent activity from multifidus and longissimus muscle spindles was recorded in the L(6) dorsal root in 30 anesthetized cats. To alter movement history, a feedback-controlled motor attached to the L(6) spinous process held (conditioned for 4 s) the L(6) vertebra at an intermediate position or at positions that either lengthened or shortened the muscles. With the vertebra returned to the intermediate position, resting spindle discharge was measured over the next 0.5 s (static test) and then during a dynamic test consisting of ramp vertebral movement at four velocities (0.2, 0.5, 1.0, 2.0 mm/s). Spindle activity during the tests was measured relative to hold-intermediate. For both tests, hold-long decreased and hold-short increased muscle spindle responsiveness. For the static test position responsiveness was not different among the velocity protocols for either hold-long or hold-short (P = 0.42 and 0.24, respectively). During the dynamic test, hold-long conditioning significantly decreased [F((3,119)) = 7.99, P < 0.001] spindle responsiveness to increasing velocity. Mean velocity sensitivity was 4.44, 3.39, and 1.41 (impulses/s)/(mm/s) for the hold-short, hold-intermediate, and hold-long protocols, respectively. The nearly 2.5-fold decrease in velocity sensitivity following hold-long was significantly less than that for either hold-intermediate (P = 0.005) or hold-short conditioning (P < 0.001). Hold-short conditioning had little effect on velocity responses during the dynamic test [F((3,119)) = 0.23, P = 0.87]. In conclusion, only movement histories that stretch but not shorten muscle spindles alter their velocity sensitivity. In the low back, forward flexion and lateral bending postures would likely be the most provocative.