This document summarizes and compares different methods for assessing foot biomechanics and gait, including video-based scoring systems and multi-segment foot models. It focuses on the Oxford Foot Model (OFM), describing its segments, joint axes, markers, and measurements. The OFM allows measurement of motion between the tibia, hindfoot, forefoot, and hallux. It provides more detailed foot kinematic data than conventional gait models. A case study example shows how the OFM could provide additional insight over standard gait analysis.

1. Understanding and modelling
the deformed foot
Sarah Jarvis
ORLAU, RJAH Orthopaedic Hospital

2. The Foot
Complex structure
Interface between body and environment
Poorly functioning foot can impact on walking ability

3. Foot Anatomy
Hallux
ForefootHindfoot
Midfoot

4. What do we currently have?

6. Video

7. Video assessments
• Physician Rating Scale (Koman et al 1993)
• Observational Gait Score (Boyd & Graham 1999)
• Edinburgh Visual Gait Score (Read et al 2003)
• Visual Gait Assessment Scale (Dickens & Smith 2006)
• Salford Gait Tool (Torro et al 2007)

8. A scoring system for midfoot break
No midfoot break Straight sole profile. Dorsiflexion at the ankle
and extension at MTP joints

9. Moderate midfoot break
Sole of the foot showing a curve
Severe midfoot break
Posterior part of the foot has a straight sole
profile but dorsiflexion occurs at the midfoot
relative to hindfoot

10. How many biomechanical models do we
have in the literature?
• Systematic review Deschamps et al 2011
• 15 multi-segment foot models in the literature
• Milwaukee foot model (Kidder et al 1996)
• Oxford Foot Model (Carson et al 2001, Stebins et al 2006)
• Heidelberg Foot measurement method (Simons et al 2006)
• IOR Foot Model (Leardini et al 2007)

11. Oxford Foot Model
• Originally designed to
document foot
deformity and as an
outcome measure for
club foot
• Compatible with Plug in
Gait
• Not reliant on x-rays
• Repeatable ?
• Uses bony landmarks
• Independent tibia
segment
• Hindfoot and forefoot
segments with single
marker for the hallux
STAL
LCAL
P1
MT
D1M
T
D5M
T
P5M
T
TOE
HLX
CAL2
CA
L1
P1M
T

12. Heidelberg Foot Measurement
Method

13. IOR Foot Model

14. Axes of the OFM
Origin: ankle
joint centre
Primary axis:
ankle joint centre
- knee joint
centre
Med-lat axis:
Bimalleolar axis
3rd : mutually
perpendicular
Tibial Axis

15. Tibia Markers
• Tibial tubercle
– most
prominent part
• Fibula head
• Shin bone –
half way
between the
tibial tubercle
and the ankle
joint

16. Hindfoot Axis
Origin: Heel
marker
Prim axis: parallel
to floor in plane
of HEE, PCA and
midpoint STL and
LCA
Med-lat axis:
perpendicular to
this plane
3rd axis: mutually
perpendicular

17. Hindfoot markers
• 3 markers on the
calcaneum (PCA,
CPEG, HEE)
• Medial hindfoot
over
sustentaculum
tali (STAL)
• 1 marker on
lateral side of
calcaneum (LCA)
• Medial and
lateral malleolar
markers

18. Forefoot Axis
Origin: Midpoint
between P5M
and P1M
Prim axis: origin
to TOE
projected into
the plane of
P5M, D5M and
D1M
Vertical axis:
perpendicular
to this plane
3rd axis:
mutually
perpendicular
Hallux
Vector: D1M - HLX

19. Forefoot and Hallux markers
• Base of 5th MT
• Head of 5th MT
• Head of 2nd MT
• Medial aspect head of
1st MT
• Medial aspect proximal
phalanx of Hallux
• Base of 1st Mt superior
aspect

21. Knee Flexion (OFM tibia)
90
-20
deg
Hindfoot/Tibia Dorsiflexion
30
-90
deg
Fore/Hindfoot Dorsiflexion
50
-50
deg
Forefoot/Tibia Dorsiflexion
30
-90
deg
Hallux Dorsiflexion
50
-50
deg
Knee Varus (OFM Tibia)
30
-30
deg
Hindfoot/Tibia Varus
50
-50
deg
Fore/Hindfoot Supination
50
-50
deg
Forefoot/Tibia Supination
50
-50
deg
Hallux Varus
50
-50
deg
Knee Rotation (OFM tibia)
10
-60
deg
Hindfoot/Tibia Rotation
50
-50
deg
Fore/Hindfoot Rotation
50
-50
deg
Forefoot/Tibia Adduction
50
-50
deg
ArchHeightIndex
70
0
mm

22. Forefoot/Tibia Dorsiflexion
30
-90
deg
Forefoot/Tibia Supination
50
-50
deg
Forefoot/Tibia Adduction
50
-50
deg

23. Fore/Hindfoot Dorsiflexion
50
-50
deg
Fore/Hindfoot Supination
50
-50
deg
Fore/Hindfoot Rotation
50
-50
deg

24. Hallux Dorsiflexion
50
-50
deg
Hallux Varus
50
-50
deg
ArchHeightIndex
70
0
mm

25. Case study
• What information does the conventional
gait model give us?
• What additional information would the
OFM give us?

27. Hindfoot/tibia

28. Hindfoot/forefoot

29. Forefoot/Tibia

30. Hallux

31. Thank You