An Introduction to Podiatric Biomechanics

David N DunningDipPodM. MChS. MSc. PGCert.(sports pod)

Ancient history of Podiatry/Chiropody

The history of foot care dates back as far as walking upright.

“Man’s foot……is the most distinctly human part of the whole of his anatomical make up….”

F Wood Jones (1949)

Socrates (471-401BC)

“To him whose feet hurt everything hurts”

To understand nature we must first try to understand ourselves.

Hippocrates (460-370BC)

Not only is Hippocrates well known for the oath but also for emphasising observation and experience and for rationalised science – particularly in medicine.

He was also well known for his work on Tyaloma and Talipes.

Leonardo DaVinci (1452-1519)

“The foot is the most marvellous of machines – and a work of art”

A great thinker, mathematician, inventor, military and civil engineer, anatomist and dreamer. He needed to understand human movement to be such a great artist.

He graphically illustrated human movement.

The Profession of Podiatry

A French surgeon wrote the first book on the treatment of foot conditions;Menoire sur les cors des pieds.Rousselot Paris 1755

From here on throughout Europe the profession grew.

With many notable exponets – Durlacher (1792-1864), Zacharie (1827-1900), Runting (1861-1954), Scholl (1882-1968)

The Profession of Podiatry

Podiatry is one of the few professions in and around medicine that have independence of diagnosis.

Podiatrists are expected to make their own clinical decisions.

The Profession of Podiatry

The traditional skills of Chiropody maintained the place of the practitioner as the expert in the treatment of the skin and its excrescences.

The name change to Podiatry in the United States (1957) and the introduction of Local Anaesthetic brought about the expansion into foot surgery.

At the same time the world of biomechanics opened up to the podiatrist and from this arguably the podiatrist became the pre-eminent foot specialist. Although recognition of this is still patchy world wide.

Merton Louis Root III. DPM, DSC, FACFO.(13th August 1922 – 25th September 2002)

Root with his co-authors –Orien and Weed - brought podiatric biomechanics into the scientific community.

Root’s contribution

Neutral position Terminology Classification of foot types An understanding of open and closed chain

kinetics. The concept of compensation Tri-planar motion and its control

The Profession of Podiatry

Since the 70s the development of the profession has grown rapidly.

UK podiatrists now have graduate level training with many optional and mandatory post registration courses to follow.

The United Kingdom NHS now employs consultant grade podiatrists in foot surgery and lower limb musculo-skeletal medicine.

There are also many more at specialist grade working in Diabetes, Rheumatology etc. (A sound, comprehensive knowledge of the foot, it’s pathologies and pathomechanics is essential)

There are nearly 8000 Registered Podiatrists working in the UK today.

The majority work in NHS clinics.Approximately 1/3rd work in private practice

and some work in the commercial sector.The NHS (England) 2002 total expenditure on

Chiropody/Podiatry £110 million.Expenditure on private Chiropody/Podiatry

£70 million a year.

Scope of practice

Traditional skills

Complementary services

Specialist skills

Surgery

Traditional skills

Non invasive sharp debridement.

Padding and strapping.

Drugs and dressings.

Insoles and shoe adaptations.

Callused nodules from the affects of Rheumatoid Arthritis.

Relieved with debridement and padding

Neglect of the simplest foot lesion can have catastrophic results

Complementary services

Physiotherapy type techniques

– eg laser

Acupuncture

Homeopathy/herbalism

Advanced Strapping

Specialist skills (Podiatric Biomechanics)

Although the study of human movement related to foot function underpins Podiatric practice. The detailed application of Podiatric biomechanics can be considered a speciality

Definition

Biomechanics is the science that examines forces acting upon and within a biological structure and effects produced by such forces.

Hay (1973)

Biomechanics is the science which studies structures and functions of biological systems using the knowledge and methods of mechanics.

Hatze (1971)

Podiatric biomechanics

Podiatric biomechanics is the study of forces acting on the human body its structure and function with particular reference to the lower limb, the foot and related pathology.

(A combination of Kinesiology and kinematology)

The use of this information in various treatment regimes to change these forces for more efficient function.

The History of Biomechanics

The seven stages of biomechanical history (Nigg)

Antiquity 650BC The middle ages 200AD The Italian renaissance 1450AD Scientific revolution 1600AD The age of enlightenment 1730AD The Gait century 1800AD The twentieth century and beyond

Antiquity continued

Plato (427-347BC)– He sowed the first

seeds of mechanics by suggesting that the best tool for the pursuit of knowledge is mathematics.

Aristole (384-322BC)

– Wrote “About the Movement of Animals” - the first scientific analysis of gait.

– To him observation was paramount.

– Aristole is also attributed as the first to explain ground reaction forces “…just as the pusher pushes, so the pusher is pushed” (Cavanagh 1990)

The Italian Renaissance

Leonardo DaVinci (1452-1519) “The foot is the most marvellous of

machines – and a work of art” A great thinker, mathematician,

inventor, military and civil engineer, anatomist and dreamer. He needed to understand human movement to be such a great artist.

He graphically illustrated human movement.

The Scientific Revolution

Sir Isaac Newton(1642-1727) “If I have been able to see farther it was because I stood

on the shoulders of giants” Galileo, Decatres, Kepler etc

His laws of motion provided the impetus to study human movement and the tools to understand it.

Newton’s laws (recap)

1st law– A body will continue in a state of rest or uniform motion in

a straight line unless an external force acts upon it.

2nd law– The rate of change of momentum of an object is directly

proportional to the force acting, and takes place in the direction in which the force acts.

3rd law– To every action there is an equal and opposite reaction.

The Gait Century

Eduard (1795-1881) and Wilhelm Weber (1804-1891)

– Die Mechanik der menschlichen Gehwerkzeuge’ (On the mechanics of Human gait tools) established an agenda for research into human gait.

Braune and Fischer In 1891 1st tri-dimensional study of human gait. Determined the Centre of Gravity of each body segment.

Etienne Jules Marey (1838-1904)

Edward Maybridge (1830-1904)

Etienne Jules Marey

Marey was a prolific worker in the field of biomechanics even inventing and using a pressure platform.He also used photography to help in the understanding of human movement.

Early motion analysis by Etienne Jules Marey

Edward Maybridge

Maybridge was a pioneer of photography particularly cine and of human movement. He linked with Marey.

The fore runners to twentieth century biomechanics.

Twentieth century

Early workers– Jules Amar “The Human Motor” an analysis of physical and

physiological components of work.– Bernstein provided the bases of theories of motor control

amongst other things.– A.V.Hill initiated the understanding of muscle function.– Elftman estimated internal forces in muscles and joints –

developed a force platform.

The pioneering work of the California University Biomechanics Lab. At San Francisco and Berkley.

Roots’ contributionLike Newton “…..he saw far because he stood on the shoulders of others.”

Triplanar motion and its control Neutral position Terminology Classification of foot types The concept of compensation An understanding of open and closed chain kinetics. And more

Root M, Orien W, Weed J; Normal and Abnormal foot function. (1977)

Planes as related to the foot

Frontal

Sagittal

Transverse

Neutral Position

Is this:-

– A flat foot– A pronated foot– An everted heel– A valgus heel– Rear foot varus– Fore foot varus/valgus– Or just a woman with

knock knees

Compensations

Fore foot Valgus Fore foot Varus

Open and Closed chain Kinetics.

Foot function

Why does the foot have 26 (or 25) bones

System of levers and pullies

The three main antipronation muscles are:-Tib. AnteriorTib PosteriorPeroneus Longus.

(Flexor Hallucis)

Assessment???