Skip to main page content
Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
, 14, 365

Movement Within Foot and Ankle Joint in Children With Spastic Cerebral Palsy: A 3-dimensional Ultrasound Analysis of Medial Gastrocnemius Length With Correction for Effects of Foot Deformation

Affiliations

Movement Within Foot and Ankle Joint in Children With Spastic Cerebral Palsy: A 3-dimensional Ultrasound Analysis of Medial Gastrocnemius Length With Correction for Effects of Foot Deformation

Peter A Huijing et al. BMC Musculoskelet Disord.

Abstract

Background: In spastic cerebral palsy (SCP), a limited range of motion of the foot (ROM), limits gait and other activities. Assessment of this limitation of ROM and knowledge of active mechanisms is of crucial importance for clinical treatment.

Methods: For a comparison between spastic cerebral palsy (SCP) children and typically developing children (TD), medial gastrocnemius muscle-tendon complex length was assessed using 3-D ultrasound imaging techniques, while exerting externally standardized moments via a hand-held dynamometer. Exemplary X-ray imaging of ankle and foot was used to confirm possible TD-SCP differences in foot deformation.

Results: SCP and TD did not differ in normalized level of excitation (EMG) of muscles studied. For given moments exerted in SCP, foot plate angles were all more towards plantar flexion than in TD. However, foot plate angle proved to be an invalid estimator of talocrural joint angle, since at equal foot plate angles, GM muscle-tendon complex was shorter in SCP (corresponding to an equivalent of 1 cm). A substantial difference remained even after normalizing for individual differences in tibia length. X-ray imaging of ankle and foot of one SCP child and two typically developed adults, confirmed that in SCP that of total footplate angle changes (0-4 Nm: 15°), the contribution of foot deformation to changes in foot plate angle (8) were as big as the contribution of dorsal flexion at the talocrural joint (7°). In typically developed individuals there were relatively smaller contributions (10 -11%) by foot deformation to changes in foot plate angle, indicating that the contribution of talocrural angle changes was most important. Using a new estimate for position at the talocrural joint (the difference between GM muscle-tendon complex length and tibia length, GM relative length) removed this effect, thus allowing more fair comparison of SCP and TD data. On the basis of analysis of foot plate angle and GM relative length as a function of externally applied moments, it is concluded that foot plate angle measurements underestimate angular changes at the talocrural joint when moving in dorsal flexion direction and overestimate them when moving in plantar flexion direction, with concomitant effects on triceps surae lengths.

Conclusions: In SCP children diagnosed with decreased dorsal ROM of the ankle joint, the commonly used measure (i.e. range of foot plate angle), is not a good estimate of rotation at the talocrural joint. since a sizable part of the movement of the foot (or foot plate) derives from internal deformation of the foot.

Figures

Figure 1
Figure 1
Moment and angle measurement set up and example of dissected origin of human gastrocnemius muscle and glenoid cavity. A. The foot strapped to the foot plates, to which also the torque wrench is attached. The gonio meter is used for measuring the angle with the horizontal. The tip of the arrow indicates the location of a reference point used for quantifying the moment measured. B. Medio-dorsal view of the dissected of human cadaver popliteal fossa and gastrocnemius muscle. Two needles (green attachments) are inserted on the most prominent point in dorsal direction of lateral and medial condyles, respectively. The tip of the scalpel inserted indicates the target point for describing the path of GM. Note that by taking this point as the closest obtainable estimate for the origin of GM a small length of GM proximal to the marked point is neglected in SCP and TD subjects. The ruler indicates a scale of cm and mm.
Figure 2
Figure 2
SCP-TD comparison: GM muscle tendon complex length. Length of the muscle-tendon complex (m+t), normalized for tibia length, plotted as a function of foot plate angle. Mean values (and SE) and third-order polynomial fitted curves are shown. (φfoot plate) is represented as deviation from the neutral position (0°), i.e. with the longitudinal axis of the tibia perpendicular to the foot plate. Note that normalized length is even different for a point at similar foot plate angle (indicated by a dashed rectangle).
Figure 3
Figure 3
Analysis of X-rays for a SCP subject after talus alignment. A. The foot in a position similar to that when exerting 0 Nm. Under high magnification markers (dashed lines and arrows) were placed for alignment and at particular insertion points of muscles and along the fibula. Note that, for example, at the navicular bone, subluxation and an extreme position (gapping) of the calcaneo-navicular-joint is noticeable. B. The foot in a position similar to that when exerting 4 Nm dorsal flexion. The talar bone was aligned with that in A. Such talar bone alignment allows distinction of contributions to foot plate movement and muscular length changes by foot deformation and crural bone movements, respectively. The markers of A. were copied to image B. (dashed lines or arrows). New markers (solid lines or arrows) placed on the reference points in the new condition. Length changes were estimated (rectangles) for GM (m. triceps surae), TA (m. tibialis anterior) and PB (m. peroneus brevis) and angular changes for the fibula and foot plate. Note that, for clarity, magnification of A. and B. are not identical. The arrow on the heel part of the foot plate is used for calibration (actual dimension = 8.98 cm). C. Inset of the forefoot to show the presence foot lengthening upon exertion of +4 Nm.
Figure 4
Figure 4
Analysis of X-rays for a TD adult subject after talus alignment. A. The foot in a position similar to that when exerting 0 Nm. Under high magnification markers (dashed lines and arrows) were placed for alignment and at particular insertion points of muscles and along the fibula. B. The foot in a position similar to that when exerting 4 Nm dorsal flexion. The talar bone was aligned with that in A. Such talar bone alignment allows distinction of contributions to foot plate movement and muscular length changes by foot deformation and crural bone movements respectively. The markers of A. were copied to image B. (dashed lines or arrows). New markers (solid lines or arrows) placed on the reference points in the new condition. Length changes were estimated (rectangles) for GM (m. triceps surae). TA (m. tibialis anterior) and PB (m. peroneus brevis) and angular changes for the fibula and foot plate, as well as calcaneal angle (not shown). The arrow on the heel part of the foot plate is used for calibration (actual dimension = 8.98 cm).
Figure 5
Figure 5
SCP-TD comparisons for absolute and normalized GM length. Inset: Schematic illustrating the concept of GM relative length with respect to tibia length (m+t -(tib)) as a (co-)determinant of ankle joint angle. A. Absolute GM muscle-tendon complex length (m+t). B. GM muscle-tendon complex length normalized for tibia length (m+t/(tib)) GM relative length (m+t -(tib)), as estimate of talocrural joint angle changes, is plotted as independent variable. For a number of data points the external moment applied to attain such positions is indicated (black font for TD and gray font for SCP, respectively). Additional statistical analysis was performed on fitted data for the overlapping GM relative lengths (i.e. equal lengths: +0.33 > (m + t)-(tib) < +1.61). Note that very different moments were applied externally for that range. Also note that GM in SCP generally operates at lower relative lengths. Mean values + SEM are plotted.
Figure 6
Figure 6
TD-SCP comparisons for foot plate angle, as well as medial gastrocnemius relative length. A. Foot plate angle with the horizontally positioned tibia as function of externally exerted moment. Note the converging SCP and TD values towards peak plantar flexion and increasing differences toward dorsal flexion. B. GM relative length (m+t -(tib)), as estimate of talocrural joint angle, is plotted as function of externally exerted moment. Note that TD-SCP differences are less dependent on exerted moment than in (A.) Mean values + SEM are plotted. In both panels the SCP/TD ratio of slopes of the lines connecting data points are shown.

Similar articles

See all similar articles

Cited by 5 PubMed Central articles

References

    1. Bax M, Goldstein M, Rosenbaum P, Leviton A, Paneth N, Dan B. et al. Proposed definition and classification of cerebral palsy. Dev Med Child Neurol. 2005;14:571–576. doi: 10.1017/S001216220500112X. - DOI - PubMed
    1. Odding E, Roebroeck ME, Stam HJ. The epidemiology of cerebral palsy: incidence, impairments and risk factors. Disabil Rehabil. 2006;14:183–191. doi: 10.1080/09638280500158422. - DOI - PubMed
    1. Himmelmann K, Hagberg G, Uvebrant P. The changing panorama of cerebral palsy in Sweden. X. Prevalence and origin in the birth-year period 1999–2002. Acta Paediatr. 2010;14:1337–1343. doi: 10.1111/j.1651-2227.2010.01819.x. - DOI - PubMed
    1. Nordmark E, Hagglund G, Lauge-Pedersen H, Wagner P, Westbom L. Development of lower limb range of motion from early childhood to adolescence in cerebral palsy: a population-based study. BMC Med. 2009;14:65. doi: 10.1186/1741-7015-7-65. - DOI - PMC - PubMed
    1. Tardieu C, Huet De La Tour E, Bret MD, Tardieu G. Muscle hypoextensibility in children with cerebral palsy: clinical and experimental observations. Arch Phys Med Rehabil. 1982;14:97–102. - PubMed

Publication types

Feedback