multi-segment foot coordination of the treated · pdf filebiomechanics laboratory joseph...

Biomechanics Laboratory
Joseph Hamill1,2, Amy Whited1,2 andGeorge Gorton2
1Biomechanics LaboratoryUniversity of Massachusetts
Amherst, MA
2Shriners Hospital For ChildrenSpringfield, MA
Multi-Segment Foot Coordinationof the Treated Clubfoot

Biomechanics LaboratoryBiomechanics Laboratory 2
Clubfoot
common congenital birth defect idiopathic unilateral or bilateral

What is Clubfoot?
3-dimensional deformity Fibrosis (Ponseti, 2001) Bony deformities (Howard &
Benson, 1993)
severe disability if left untreated

Four Primary Components
forefoot cavus hindfoot varus forefoot adductus equinus

Biomechanics LaboratoryBiomechanics Laboratory
Treatment ultimate goal of treatment:
to reduce the four primary components of the deformity functional, pain-free foot with good mobility
2 standard treatment options Ponseti casting technique Comprehensive Surgical Release (CSR)
surgical procedures decreased from 70% in 1996 to 10% in 2006 Ponseti casting considered the Gold-standard (Church et al.,
2012; Zoints, Zhao, Hitchcock, Maewal & Ebramzadeh, 2010)
(Ponseti, 1992)

Ponseti Casting Technique progressive series of casts and manipulations
correct inverted and supinated foot during infancy
followed by simple tenotomy of the Achilles Tendon correct equinus after casting period

Ponseti Casting Technique
Denis Browne Bar prevent recurrence of the primary components of the deformity
variability in long term results reported for Ponseticasting

Summary of Gait Analysis Results
What we know: differences in kinematics and kinetics single segment foot models inaccurate for clinical decision
making for patients with foot impairments
What we want to know: how do these approaches compare to one another at longer-
term follow up? how do patients treated with these approaches differ in terms of
kinematics, kinetics and coordinative function? specifically, how does the coordinative function of the forefoot
rearfoot differ between treatment approaches?

Evaluation of Treatment Effectiveness radiographic measurements
range of motion measurements
numerous rating scales
these measures do not correlate well with dynamic foot function not good measures of long term foot function (Huber & Dutoit, 2014;
Ponseti 1996)
need to understand the interaction of the foot segments relative to one another to assess foot function

Purpose
to examine differences in lower extremity kinematics and kinetics between Ponseti treatment and non-involved controls
to determine the lower extremity coordination in individuals treated with the Ponseti casting 5-7 years post-treatment

Participant Characteristics inclusion criteria for treatment group:
unilateral idiopathic clubfoot
5-7 years post-treatment
treated with Ponseti casting
exclusion criteria for control group: braces/orthoses
further clubfoot surgery
inclusion criteria for control group: gender and age matched to treatment group
exclusion criteria for control group: any orthopaedic deformity or surgery

Experimental Setup
10 infrared cameras to collect 3D kinematic data 240 Hz sampling rate
2 force platforms (1080 Hz sampling rate)
force and motion capture data synchronized in
time
timing lights to determine walking speed

51 retro-reflective markers
Experimental Setup

Experimental Setup
Modified multi-segment foot model (Leardini et al., 2007)

all local coordinate systems are oriented anatomically
rearfoot LCS
shank LCS
1st metatarsal LCSmidfoot LCS
Experimental Setup

Protocol
participant assent/guardian consent
guardian complete Physical Activity Readiness
Questionnaire (PAR-Q), lower extremity injury history
and demographics
explanation and practice of walking procedure
Anthropometric data collected

Protocol
standing trial barefoot
kinematic and Kinetic data collection
2 barefoot conditions free-living walking speed fixed walking speed: 1.0 m/s (5%)
5 successful trials per condition one complete stride of left and right lower extremities contacts force platform at required speed

Coordination Analysis
inversion/eversion of the forefoot-rearfoot coupling
internal/external tibial rotation-rearfoot
inversion/eversion coupling
internal/external rotation of the femur-tibia coupling
flexion/extension of the foot-tibia coupling

Modified Vector Coding Technique
(Chang, Van Emmerik & Hamill, 2008)
Phase Angle
Segment Angle-Angle Plot
Proximal Phase
Proximal Phase
Distal Phase
Distal Phase

Segment coordination Interaction between 2 segments Coupled
Coordinative patterns:
Distal-phase

Proximal-phase

In-phase

Anti-phase

in-phase anti-phase
Frontal Plane Coordination
inversion eversion
forefootrearfoot

Coordination Variability
Time course (%)
Adapted from (Van Emmerik, Miller & Hamill, 2013)

Results
-5
0
5
10
15
20
Ang
le (d
egre
es)
% Stance
Control Ponseti
100110120130140150160170180
Ang
le (d
egre
es)
% Stance
Control Ponseti
-4
-2
0
2
4
6
8
10
% Stance
Control Ponseti
MTP Angle Sagittal Ankle Angle
Inversion/Eversion Angle

Ankle DF/PF Moment
Results
-1.4
-1.2
-1
-0.8
-0.6
-0.4
-0.2
0
0.2
Join
t M
omen
t (N
.m/
kg)
% Stance
Control Ponseti
-0.04-0.02
00.020.040.060.08
0.10.120.14
Join
t Mom
ent (
N.m
/kg)
% Stance
Control Ponseti
-0.08
-0.06
-0.04
-0.02
0
0.02
0.04
Join
t Mom
ent (
N.m
/kg)
% Stance
Control Ponseti
Ankle Varus/Valgus Moment
Ankle Int./Ext. Rotation Moment

Results
0
10
20
30
40
50
60
FF-RF RF-Tib Fem-Tib FF-RF RF-Tib Fem-Tib FF-RF RF-Tib Fem-Tib
Early Mid Late
% Stance
Coo
rdin
atio
n Va
riabi
lity
(Deg
.)
ControlPonseti

Discussion
lower extremity joint angles somewhat different between Ponseti-treated clubfoot and controls
MTP and INV/EV angles were not different between groups
PF/DF angle was significantly reduced in Ponseti-treated group
PF/DF and internal/external moments are significantly reduced in the Ponseti-treated individuals

Discussion
interestingly, forefoot-rearfoot coordination variability is increased in all couplings at all stages in the stance phase in the Ponseti-treated group
in prior research on coordination variability and pathology, greater variability indicated an approach towards the healthy state
this increase in variability indicates that the Ponseti-treated individuals are able to use all movement possibilities of the foref/rearfoot interaction during walking

Discussion

Conclusions
we cannot confirm that the Ponseti method is the best treatment procedure for clubfoot
in the kinematics and kinetics of

multi-segment foot coordination of the treated · pdf filebiomechanics laboratory joseph...

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