Foot biomechanics simplified, and a close look at the function of foot arch supports. Learn more at www.GraMedica.com.

1. Michael E. Graham, DPM, FACFAS, FAENS
Macomb, Michigan USA

2. • Biomechanical principals
• What is an arch support/orthosis?
• What is its function?
• What can it accomplish?
• What role does it play in the treatment of
flatfoot/talotarsal displacement?

4. Parts of the gait/walking cycle
SWING phase CONTACT phase

5. We don’t care too much about
the swing phase.

6. We need to focus very much on the
contact phase.
Let’s take a close look.

7. It’s not that complicated!

8. Primary motions of the foot
during the contact phase of walking.

9. Supination
• Locks the joints of the foot to create a stable
lever-arm.
• This should be the dominate position of the
talotarsal mechanism – 2/3 motion.

10. Pronation
• Allows the foot to act as a mobile adaptor to
the weightbearing surface.
• Should only consist of 1/3 total talotarsal
motion.

11. Neutral Position
• Part of the stance phase when the foot is
neither supinated nor pronated.
• Minimal strain on the supporting tissues.

12. During the
Contact Phase
• There are certain times when the talotarsal joint needs
to be supinating, in neutral position, or pronating.
• This is very important for proper biomechanical foot
function.
• If pronation/supination occur at the wrong time during
the walking cycle, compensation of the pathologic
strain/forces will be acting on the tissues.
• Eventually, critical point is reach where the tissues can
no longer handle those forces. The tissues begins to
become inflamed and send a warning signal (PAIN) that
something is wrong.

13. Unfortunately, the majority of the
medical community is only
concerned with covering up the pain
without eliminating what has caused
that pain in the first place.

14. Contact Phase of the Gait Cycle with a
Stable Talotarsal Joint Mechanism
Heel strike Early Mid-stance Late Mid-stance Heel-lift Toe-off
Supinated Slight Supinated
pronation
Neutral Position

15. Talar position during the walking/gait cycle
Maximally Neutral Maximally
Supinated Talotarsal Pronated Displaced
Talotarsal Joint Talotarsal Talotarsal Joint
Joint Joint

16. Center Line of Gravity
This is the
center of forces
passing through the foot.

17. Normal Center Line of Gravity

18. Normal Center Line of Gravity
Toe off
Heel Lift
Late Mid-stance
Early Mid-stance
Heel Strike

19. Talotarsal Joint Displacement
• Unlocks the stability of the foot.
• When the foot is supposed to be in a
supinated position it is in a pronated
position.
• There is a longer than normal period of
pronation = hyperpronation

20. Stance Phase of the Gait Cycle with
Displacement of Talotarsal Joint Mechanism

21. What is the role of an arch
support?

22. What is an orthosis?
• It is an external appliance/device
• Used to provide support
• Attempts to prevent or correct for a plantar
foot deformity
• Tries to improve foot function

23. What is their function?
• Support “fallen” arches
• Align- biomechanical defects
• Correct- alignment issues
• Cushion- bony prominences
• Protect-remove pressure from callused/ulcer
areas.

24. Type of foot orthoses
• Soft
• Semi-flexible/rigid
• Rigid

25. Made of many different materials
• Foam
• Thermoplastic
• Carbon fiber
• Hard plastics
• Soft plastics

26. How are they made?

27. Ideal Method

28. “Electronic” Methods

29. “Easy” Method

30. “Commercial” Method

31. “Off the shelf”/pre-made generic

32. Where is the evidence?

33. Internal imaging.

34. Is this arch support working?

35. An arch support, even if custom-
made, cannot prevent/stabilize a
talotarsal displacement.

36. They can cushion the plantar
aspect of the foot.

37. They can possibly help to rebalance
the center of gravity but the
evidence is weak.

38. Not all patients are surgical
candidates and something is better
than nothing.

39. Limitations of arch supports
• Cannot control talotarsal joint mechanism and
therefore have a difficult time realigning foot
structure.
• Only function when being used, if the patient
is not wearing them in their shoes or going
barefoot there is not correction.
• Have to wear bigger/limited shoe style
• Method to make them still isn’t perfected.

40. The worst of it is that an arch
support may give the individual a
false sense of correction- the arch
support really isn’t fixing anything.

41. Advantages of Arch Supports
• Non-surgical option
• Can help to off-weight prominent areas to the
bottom of the foot.
• Can help to re-align the center of gravity
through the bottom of the foot.
• May give the patient enough correction to
alleviate their pain.

42. Doesn’t an internal deformity
demand internal correction?

44. Refuse to ignore or cover-up your
misaligned feet.
www.alignmyfeet.com

45. There is an internal option with
exploring.

46. Questions?