The Gait Deviation Index (GDI) is a dimensionless parameter that evaluates the deviation of kinematic gait from a control database. The GDI can be used to stratify gait pathology in children with cerebral palsy (CP). In this paper the repeatability and uncertainty of the GDI were evaluated. The Correlation between the GDI and the Gross Motor Function Classification System (GMFCS) was studied for different groups of children with CP (hemiplegia, diplegia, triplegia and quadriplegia). Forty-nine, typically developing children (TD) formed our database. A retrospective study was conducted on our 3D gait data and clinical exams and 134 spastic children were included. Sixteen TD children completed the gait analysis twice to evaluate the repeatability of the GDI (test-retest evaluation). Monte Carlo simulations were applied for all groups (TD and children with CP) in order to evaluate the propagation of errors stemming from kinematics. The repeatability coefficient (2SD of test-retest differences), obtained on the GDI for the 16 TD children (32 lower limbs) was ± 10. Monte Carlo simulations showed an uncertainty ranging between 0.8 and 1.3 for TD children and all groups with CP. The Spearman Rank correlation showed a moderate correlation between the GDI and the GMFCS (r=-0.44, p<0.0001).

Lower limb (LL) muscle morphology and growth are altered in children with cerebral palsy (CP). Muscle alterations differ with age and with severity of motor impairment, classified according to the gross motor classification system (GMFCS). Muscle alterations differ also with orthopedic intervention, frequently performed at the level of the shank muscles since an early age, such as the gastrocnemius. The aim was to investigate the alterations of treatment-naïve pelvis and thigh muscle lengths and volumes in children with GMFCS levels I and II, of varying ages. 17 children with CP (GMFCS I: N = 9, II: N = 8, age: 11.7 ± 4 years), age-matched to 17 typically developing (TD) children, underwent MRI of the LL. Three-dimensional reconstructions of the muscles were performed bilaterally. Muscle volumes and lengths were calculated in 3D and compared between groups. Linear regression between muscle volumes and age were computed. Adductor-brevis and gracilis lengths, as well as rectus-femoris volume, were decreased in GMFCS I compared to TD (p < 0.05). Almost all the reconstructed muscle volumes and lengths were found to be altered in GMFCS II compared to TD and GMFCS I. All muscle volumes showed significant increase with age in TD and GMFCS I (R 2 range: 0.3-0.9, p < 0.05). Rectus-femoris, hamstrings and adductor-longus showed reduced increase in the muscle volume with age in GMFCS II when compared to TD and GMFCS I. Alterations of treatment-naïve pelvis and thigh muscle volumes and lengths, as well as muscle growth, seem to increase with the severity of motor impairment in ambulant children with CP.

Background A thorough review of the available orthopaedic literature shows significant controversies, inconsistencies and sparse data regarding the terminology used to describe foot deformities. This lack of consensus on terminology creates confusion in professional discussions of foot anatomy, pathoanatomy and treatment of deformities. The controversies apply to joint movements as well as static relationships between the bones. Description The calcaneopedal unit (CPU) is a specific anatomical and physiological entity, represented by the entire foot excepted the talus. The calcaneus, midfoot and forefoot are solidly bound by three strong ligaments that create a unit that articulates with the talus. The movement of the CPU is complex, as it rotates under the talus, around the axis of Henke that coincides with the talo-calcaneal ligament of Farabeuf. This calcaneopedal unit is deformable. It is compared with a twisted plate, able to adapt to many physiological situations in standing position, in order to acheive a plantigrade position. Moreover, the calcaneopedal unit and the talo-tibiofibular complex are interdependent; rotation of the latter produces morphologic modifications inside the former and vice versa. Purpose This paper is a review article of this concept and of its physiopathological applications.

 To study the Influence of postural alignment parameters on gait kinematics  134 asymptomatic adults had gait analysis & postural parameters assessed on X-rays  Increase in sagittal vertical axis is related to larger knee flexion in stance  Increase in radiological pelvic tilt is related to reduced pelvic obliquity  Increase in thoracic kyphosis is related to reduced hip sagittal mobility

Localization of the hip joint center (HJC) is essential in computation of gait data. EOS low dose biplanar X-rays have been shown to be a good reference in evaluating various methods of HJC localization in adults. The aim is to evaluate predictive and functional techniques for HJC localization in typically developing (TD) and cerebral palsy (CP) children, using EOS as an image based reference. Eleven TD and 17 CP children underwent 3D gait analysis. Six HJC localization methods were evaluated in each group bilaterally: 3 predictive (Plug in Gait, Bell and Harrington) and 3 functional methods based on the star arc technique (symmetrical center of rotation estimate, center transformation technique and geometrical sphere fitting). All children then underwent EOS low dose biplanar radiographs. Pelvis, lower limbs and their corresponding external markers were reconstructed in 3D. The center of the femoral head was considered as the reference (HJCEOS). Euclidean distances between HJCs estimated by each of the 6 methods and the HJCEOS were calculated; distances were shown to be lower in predictive compared to functional methods (p<0.0001). Contrarily to findings in adults, functional methods were shown to be less accurate than predictive methods in TD and CP children, which could be mainly due to the shorter thigh segment in children. Harrington method was shown to be the most accurate in the prediction of HJC (mean error≈18mm, SD=9mm) and quasi-equivalent to the Bell method. The bias for each method was quantified, allowing its correction for an improved HJC estimation.

Background: Adults with spinal deformity (ASD) are known to have postural malalignment affecting their quality of life. Classical evaluation and follow-up are usually based on full-body static radiographs and health related quality of life questionnaires. Despite being an essential daily life activity, formal gait assessment lacks in clinical practice.Research Question: What are the main alterations in gait kinematics of ASD and their radiological determinants? Methods: 52 ASD and 63 control subjects underwent full-body 3D gait analysis with calculation of joint kinematics and full-body biplanar X-rays with calculation of 3D postural parameters. Kinematics and postural parameters were compared between groups. Determinants of gait alterations among postural radiographic parameters were explored. Results: ASD had increased sagittal vertical axis (SVA:34 ± 59 vs − 5 ± 20 mm), pelvic tilt (PT:19 ± 13 vs 11 ± 6 • ) and frontal Cobb (25 ± 21 vs 4 ± 6 • ) compared to controls (all p < 0.001). ASD displayed decrease walking speed (0.9 ± 0.3 vs 1.2 ± 0.2 m/s), step length (0.58 ± 0.11 vs 0.64 ± 0.07 m) and increased single support (0.45 ± 0.05 vs 0.42 ± 0.04 s). ASD walked with decreased hip extension in stance (− 3 ± 10 vs − 7 ± 8 • ), increased knee flexion at initial contact and in stance (10 ± 11 vs 5 ± 10 • and 19 ± 7 vs 16 ± 8 • respectively), and decreased knee flexion/extension ROM (55 ± 9 vs 59 ± 7 • ). ASD had increased trunk flexion (12 ± 12 vs 6 ± 11 • ) and reduced dynamic lumbar lordosis (− 11 ± 12 vs − 15 ± 7 • , all p < 0.001). Sagittal knee ROM, walking speed and step length were negatively determined by SVA; lack of lumbar lordosis during gait was negatively determined by radiological lumbar lordosis. Significance: Static compensations in ASD persist during gait, where they exhibit a flexed attitude at the trunk, hips and knees, reduced hip and knee mobility and loss of dynamic lordosis. ASD walked at a slower pace with increased single and double support times that might contribute to their gait stability. These dynamic discrepancies were strongly related to static sagittal malalignment.

OBJECTIVEThe aim of this study was to determine if the apical vertebra (AV) in patients with adolescent idiopathic scoliosis (AIS) is the most rotated vertebra in the scoliotic segment.METHODSA total of 158 patients with AIS (Cobb angle range 20°–101°) underwent biplanar radiography with 3D reconstructions of the spine and calculation of vertebral axial rotations. The type of major curvature was recorded (thoracic, thoracolumbar, or lumbar), and both major and minor curvatures were included. The difference of levels (DL) between the level of maximal vertebral rotation (LMVR) and the AV was calculated as follows: DL = 0 if LMVR and AV were the same, DL = 1 if LMVR was directly above or below the AV, and DL = 2 if LMVR was separated by 1 vertebra or more from the AV. To investigate which factors explained the divergence of the LMVR from the AV, multinomial models were computed.RESULTSThe distribution of the DL was as follows: for major curvatures, 143 were DL = 0, 11 were DL = 1, and 4 were DL = 2; and for minor curvatures, 53 were DL = 0, 9 were DL = 1, and 31 were DL = 2. The determinants of a DL = 2 (compared with DL = 0) were lumbar curvature (compared with thoracic; adjusted OR 0.094, p = 0.001), major curvature (compared with minor; adjusted OR 0.116, p = 0.001), and curvatures with increasing apical vertebral rotation (adjusted OR 0.788, p < 0.001).CONCLUSIONSThis study showed that the AV is the most rotated vertebra in the majority of major curvatures, while in minor curvatures, the most rotated vertebra appears to be the junctional vertebra between major and minor curvatures in a significant proportion of cases.

Skeletal abnormalities, affecting posture and walking pattern, increase with motor impairment in children with cerebral palsy (CP). However, it is not known whether these skeletal malalignments occur in children with slight motor impairment. Our aim was to evaluate skeletal malalignment at the level of the pelvis and lower limbs in ambulant children with CP, with slight motor impairment, using a low dose biplanar X-ray technique. Twenty-seven children with spastic CP (mean age: 10.9±4years, 7 Hemiplegia, 20 Diplegia, GMFCS levels I:17, II:10), with no previous treatments at the hips and knees, underwent EOS(®) biplanar X-rays. A control group consisting of 22 typically developing children was also included. Three-dimensional reconstructions of the pelvis and lower limbs were performed in order to calculate 11 radiological parameters related to the pelvis, acetabulum and lower limbs. Pelvic incidence and sacral slope were significantly increased in children with CP compared to TD children (48°±7° vs. 43°±8°, 42°±7° vs. 38°±5°, respectively, p=0.003). Acetabular parameters did not significantly differ between the two groups. Femoral anteversion and neck shaft angle were significantly increased in children with CP (25°±12° vs. 14°±7°, p<0.001; 134°±5° vs. 131°±5°, p=0.005 respectively). No difference was found for tibial torsion. This study showed that even slightly impaired children with CP have an anteverted and abducted femur and present positional and morphological changes of the pelvis in the sagittal plane. The orientation of the acetabulum in 3D seems to not be affected when children with CP present slight motor impairment.