Measuring gait kinematics in patients with severe hip osteoarthritis using wearable sensors

BackgroundThe popularity of inertial sensors in gait analysis is steadily rising. To date, an application of a wearable inertial sensor system for assessing gait in hip osteoarthritis (OA) has not been reported.Research question: Can the known kinematic differences between patients with hip OA and asymptomatic control subjects be measured using the inertial sensor system RehaGait®?MethodsThe patients group consisted of 22 patients with unilateral hip OA scheduled for total hip replacement. Forty-five age matched healthy control subjects served as control group. All subjects walked for a distance of 20 m at their self-selected speed. Spatiotemporal parameters and sagittal kinematics at the hip, knee, and ankle including range of motion (ROM) were measured using the RehaGait® system.ResultsPatients with hip OA walked at a slower walking speed (−0.18 m/s, P < 0.001) and with shorter stride length (−0.16 m, P < 0.001), smaller hip ROM during stance (−11.6°, P < 0.001) and swing (−11.3°, P < 0.001) and smaller knee ROM during terminal stance and swing (−9.0° and−11.5°, P < 0.001). Patients had a smaller hip ROM during stance and swing and smaller knee ROM during terminal stance and swing in the affected compared to the unaffected side (P < 0.001).SignificanceThe differences in spatiotemporal and kinematic gait parameters between patients with hip OA and age matched control subjects assessed using the inertial sensor system agree with those documented for camera-based systems. Hence, the RehaGait® system can measure gait kinematics characteristic for hip OA, and its use in daily clinical practice is feasible.     

The association of equinus and primary genu recurvatum gait in cerebral palsy

Primary genu recurvatum (GR) is less investigated and data presenting the prevalence among patients with bilateral spastic cerebral palsy (BSCP) is lacking in the literature. Equinus is mentioned as one of the main underlying factors in GR, but its influence on the severity and onset type of GR is mainly unanswered, yet. Hence, the purpose of this retrospective study was to assess the prevalence of GR in a large sample size in children with BSCP and to investigate sagittal plane kinematics to evaluate the influence of equinus on different GR types using data of three-dimensional gait analysis. GR was defined as a knee hyperextension of more than one standard deviation of an age matched control group during stance phase in either one or both of the limbs. Primary GR was defined as a GR without having previous surgery regarding the lower extremity, no selective dorsal rhizotomy and/or interventions like botulinum toxin injection, shock wave therapy or serial casting during the last 6 months in the patient history. In a retrospective study 463 patients with BSCP (GMFCS Level I–III) received three-dimensional gait analysis and were scanned for the presence of primary GR. Finally, 37 patients (23 males, 14 females) matched the determined inclusion criteria and were therefore included for further analysis in this study. Out of those patients seven walked with orthoses or a walker and were excluded from further statistical comparison: Kinematics of the lower limbs were compared between patients having severe (knee hyperextension > 15°) and moderate (knee hyperextension 5–15°) GR and between patients showing an early (first half of stance phase) and a late (second half of stance phase) GR. Primary GR was present in 37 patients/52 limbs (prevalence 8.0/5.6%). Severe GR was associated with a decreased ankle dorsiflexion compared with moderate GR. Early GR showed an increased knee hyperextension compared to late GR. In conclusion GR is less frequent compared with crouch or stiff gait. Our findings support the importance of equinus as a major underlying factor in primary GR. In this context the influence of equinus seems to be more important in early GR.     

Recovery of locomotion after chronic spinalization in the adult cat

Cats were spinalized (T13) as adults and were trained to walk with the hindlimbs on a treadmill. After 3 weeks to 3 months and up to 1 year depending on the animal, all were capable of walking on the plantar surface of the feet and support the weight of the hindquarters. Interactive training appeared to accelerate the recovery of locomotion and maintain smooth locomotor movements. Despite the obvious loss of voluntary control and equilibrium which the experimenter partially compensated for by maintaining the thorax and/or the tail, the cats could walk with a regular rhythm and a well-coordinated hindlimb alternation at speeds of 0.1-1.2 m/s. Cycle duration as well as stance and swing duration resembled those of normal cats at comparable speeds. The range of angular motion was also similar to that observed in intact cats as was the coupling between different joints. The EMG activity of the hindlimb and lumbar axial muscles also retained the characteristics observed in the intact animal. Some deficits such as a dragging of the foot in early swing and diminution of the angular excursion in the knee were seen at later stages. Thus, the adult spinal cat preparation is considered as a useful model to study the influence of different types of training and of different drugs or other treatments in the process of locomotor recovery after injury to the spinal cord.     

冷刺激下食指运动学及动力学特性研究

目的考察冷刺激对食指运动学及动力学特性的影响。方法为减少对食指屈伸的影响,采用高速摄影仪记录食指屈伸运动过程的方法,记录食指在自然状态和冷水刺激两种情况下的屈伸运动,通过自行编写的程序对视频文件进行处理,得到食指各关节角度随时间的变化,最后通过一个包含两块肌肉(FDS:flexordigitorumsuperfi-cialis,FDP:flexordigitorumprofundus)的肌骨骼模型计算得到肌肉力随时间的变化关系。结果冷水刺激后,食指第二关节在屈伸过程中的平均角速度变小。冷水刺激前后,FDP肌肉力没有太大的变化,而FDS肌肉力在弯曲结束时增加了1倍左右。结论本文通过影像结合图像处理的方式得到了食指在屈伸过程中的轨迹信息,并通过简化建立了连接食指表观信息与内部肌肉力的计算模型,进一步讨论了冷水刺激前后食指的运动学和动力学特性。     

人体运动力学分析方法的回顾与展望

运动力学作为生物力学重要的分支和前沿方向,近年来在运动数据获取、力学参数测量及人体动力学模型建立等方面取得了许多重大进展,并对运动损伤预防及康复医学等领域产生了重要的影响。人体内力环境是运动、负荷、生物学和形态学相互作用的结果,准确测量和估计人体内力环境是运动生物力学的研究重点和难点,而个性化的数据获取和模型建立也是获得物理与生理上有效的组织生物力学预测的关键。该文回顾了运动学和动力学的研究与发展,为运动力学分析方法提供系统与全面的工作框架,并展望学科未来的应用与发展趋势,为相关领域的研究者提供参考。     

Diabetic gait and posture abnormalities: A biomechanical investigation through three dimensional gait analysis

Background

Diabetic sensorimotor polyneuropathy is a long-term diabetic complication. It is involved in the pathogenesis of the diabetic foot, which is a major cause of morbidity and mortality. The study aims to investigate the effects of diabetic polyneuropathy on gait and posture.

Methods

Sixty seven subjects were enrolled: 21 diabetics without polyneuropathy, 26 with polyneuropathy, 20 controls (respectively, mean age 63.8 (SD 5.4), 63.2 (SD 5.6), 59.0 (SD 5.2) years, mean body mass index 26.3 (SD 2.5), 25.6 (SD 3), 24.0 (SD 2.9)). Postural and morphological evaluation and gait analysis were performed. Physical examination, together with a motion capture system synchronized with two force plates and two baropodometric systems were used. We evaluated lower limb mobility, foot deformities, trunk and pelvic posture, knee and heel position, plantar foot arch, three dimensional kinematics and kinetics during gait. The effect of peripheral vascular disease and microangiopathy on trunk and lower limb motion was also evaluated.

Findings

Trunk and lower limb joint mobility (in static and dynamic states) were more reduced in diabetics either with or without polyneuropathy on each plane; however in diabetics with polyneuropathy significantly lower ranges of motion were registered. Furthermore, both groups showed significant reductions in each joint moment and velocity (P ? 0.003) during gait. In presence of both vasculopathy and microangiopathy a further significant reduction (P ? 0.001) was noticed.

Interpretation

Altered gait and posture were found in diabetic patients irrespective of polyneuropathy. This approach may be relevant to predict the risk ulceration before clinically detectable neuropathy.     

Motion characteristics of the lumbar spinous processes with degenerative disc disease and degenerative spondylolisthesis

Objective

Recently, interspinous process devices have attracted much attention since they can be implanted between the lumbar spinous processes (LSP) of patients with degenerative disc disease (DDD) and degenerative spondylolisthesis (DLS) using a minimally invasive manner. However, the motion characters of the LSP in the DLS and DDD patients have not been reported. This study is aimed at investigating the kinematics of the lumbar spinous processes in patients with DLS and DDD.

Methods

Ten patients with DDD at L4–S1 and ten patients with DLS at L4–L5 were studied. The positions of the vertebrae (L2–L5) at supine, standing, 45° trunk flexion, and maximal extension positions were determined using MRI-based models and dual fluoroscopic images. The shortest ISP distances were measured and compared with those of healthy subjects that have been previously reported.

Results

The shortest distance of the interspinous processes (ISP) gradually decreased from healthy subjects to DDD and to DLS patients when measured in the supine, standing, and extension positions. During supine-standing and flexion–extension activities, the changes in the shortest ISP distances in DDD patients were 2 ± 1.2 and 4.8 ± 2.1 mm at L4–L5; in DLS patients they were 0.5 ± 0.4 and 2.8 ± 1.7 mm at L4–L5, respectively. The range of motion is increased in DDD patients but decreased in DLS patients when compared with those of the healthy subjects. No significantly different changes were detected at L2–L3 and L3–L4 levels.

Conclusion

At the involved level, the hypermobility of the LSP was seen in DDD and hypomobility of the LSP in DLS patients. The data may be instrumental for improving ISP surgeries that are aimed at reducing post-operative complications such as bony fracture and device dislocations.     

In vivo flexion/extension of the normal cervical spine

Twenty-two women (age range 25-49 years, average 30.9 years) and twenty-two men (age range 23-42 years, average 31.6 years), all healthy and asymptomatic, underwent passive flexion/extension examinations of the cervical spine. Functional x-rays were taken and analyzed using a computer-assisted method that quantified intervertebral rotations, translations, and locations of the centers of rotation for each level C1-C2-C6-C7. The aim of the study was to establish values for these parameters for a normal population as related to age and gender. In the process, a statistically significant difference was found in the average value of rotation between male and female groups at the C5-C6 level. A new parameter, the ratio between translation and rotation, was also established and may prove useful for clinical diagnoses. This parameter has a smaller error associated with it than do pure translations and may aid the clinician by helping to account for the large variation in rotatory ranges of motion within the population. This translation/rotation ratio indicated highly significant differences in the lower segments of the cervical spine between gender groups.     

The effect of ankle bracing on landing biomechanics in female netballers

ObjectivesInvestigate the impact of lace-up ankle braces on landing biomechanics.DesignWithin-subject repeated measures. Participants completed a drop jump, drop land, and netball-specific task in braced and unbraced conditions.SettingBiomechanical research laboratory.ParticipantsTwenty female high school netballers.Main outcome measuresLeg, knee, and ankle stiffness, knee/ankle stiffness ratio, knee and ankle sagittal excursion, peak vertical ground reaction force, time-to-peak vertical ground reaction force, and loading rate.ResultsIn the brace condition leg stiffness increased bilaterally during the drop land (ES = 0.21, 0.22), ankle stiffness increased bilaterally during the drop jump (ES = 0.37, 0.29) and drop land (ES = 0.40, 0.60), and knee/ankle stiffness ratio decreased in all three tasks (ES = −0.22 to −0.45). Ankle sagittal excursion decreased bilaterally during the drop jump (ES = −0.35, −0.53) and drop land (ES = −0.23, −0.46), and decreased in the lead limb during the netball jump (ES = −0.36). Knee excursion decreased bilaterally during the drop jump (ES = −0.36, −0.40) and in the lead limb during netball task (ES = −0.59). Lead limb TTP was greater during the netball jump (ES = 0.41).ConclusionsLace-up ankle braces may increase leg and joint stiffness and reduce joint excursion during landing but do not appear to affect landing forces. The observed effect on landing biomechanics may predispose young netballers to injury.