biomechanics of f t and podiatry physical therapy

Biomechanics of F t and Podiatry Physical Therapy

Huei-Ming Chai, PT PhDSchool of Physical Therapy

National Taiwan University, Taipei, TaiwanJune 21, 2008

孟子曰 : 人之异于禽兽者几希，庶民去之，君子存之。舜明于庶物，察于人伦，由仁义行，非行仁义也 。 -- 离娄下第十九

• plantigrade of foot

• widening of pelvis

• erect spine

• delicate function of hand

孟子曰 : 人之异于禽兽者几希

Plantigradeplanta = sole gradi = walk

bipedal quadripedal

ankle

ankle

MP joints

Biomechanics of Foot and Podiatry Physical Therapy

Biomechanics of Foot– Bony structure and joints of foot– Types of foot

• Foot Orthotic Therapy

• Podiatry Physical Therapy

Medial Aspect of Foot

subtalar joint

Forefoot Midfoot Rearfoot

medial longitudinal arch

calcaneus

talus

navicular

1st metatarsalphalanx

1st cuneiformMT head

Superior Aspect of Foot

calcaneus

talus

navicularmetatarsals

phalanges

Forefoot Midfoot Rearfoot

cuneiforms

cuboidmidtarsal joint

fibula

talus

tibia

mediallateral

Anterior Aspect of Foot

subtalar jointcalcaneus

MTHs

anterior aspect

Neutral Foot ( 正中足 )

• Subtalar joint is placed at the neither pronated nor supinated position

• subtalar neutral position– calcaneus ground– tibia ground– metatarsal heads // ground

subtalar joint neutral

tibial bisecting line

calcaneual bisecting lineplantar surface

of MTHs

Pronated Foot ( 內旋足 )

non-weight-bearing weight bearing

forefoot varus STJ

pronated

(plantigrade)

Talus shiftsmedially +inferiorly

STJ neutral

Pronated Foot

• pronation of rearfoot with respect to forefoot (decreased arch) as foot is loaded

• NOT structural flat foot

• resulting in pain or dysfunction of foot or other WB joints

NWB

4.6 cm

WB

3.0 cm

Wearing Pattern in Pronated Foot

pronated foot

medial side wearing

內

外

normal wearing pattern

neutral stance

WBstance

Problems Related to Pronated Foot

• Plnatar faciitis

• Achilles tendinitis

• Arch pain

• Metatarsalgia

• Tibialis posterior tendinitis

• Chondromalacia patella

• Low back pain

Supinated Foot ( 外旋足 )

non-weight-bearing weight bearing

forefoot valgus

STJ neutral

STJsupinated

(plantigrade)

Talus shiftslaterally +superiorly

Supinated Foot

• supination of rearfoot with respect to forefoot (increased arch) as foot is loaded

• NOT structural high-arch foot

• resulting in pain or dysfunction of foot or other WB joints

NWB

5.5 cm

WB

6.2 cm

Three Foot Types at Stance

外旋足supinated foot

10%

正中足neutral foot

60%

內旋足pronated foot

30%

Biomechanics of Foot and Podiatry Physical Therapy

• Biomechanics of Foot

Foot Orthotic Therapy– Concept I: plantigrade– Concept II: total contact– Concept III: neutral foot

• Podiatry Physical Therapy

Concept I: Plantigrade

• to provide plantigrade by 3-point contact to the ground

• examples– therapeutic exercises– orthopedic surgery– shoe modifications 5th MTH

heel

1st MTH

Concept II: Total Contact

• to provide even distribution of WB onto whole foot by total plantar surface of foot contacting ground

• Increase area of contact to decrease pressure since P = F /A

• examples:– filling stuff into shoes to support the arch– total contact orthoses

transverse arch

medial longitudinal

arch

lateral longitudinal

arch

Concept III: Neutral Foot

• to provide balance of soft tissues by control subtalar joint in neutral position

• examples:– functional foot orthoses

STJ neutral

tibial bisecting

line

calcaneual bisecting lineplantar surface

of MTHs

Functional Foot Orthosis

• to maintain the foot in the subtalar neutral position

• to disperse the body weight as even as possible

Neutral Cast -- Prone Technique

Making A Positive Mold

Fabrication

Various Posting

heel liftmetatarsal pad

medial post

lateral post

Benefits from Using Functional Foot Orthosis

• To re-align foot structure for malalignment – to control excessive motion– to change weight bearing pattern– to equalize leg length– to support deformed structure

• To relieve pain for painful foot

• To re-distribute weight bearing for insensitive foot

Biomechanics of Foot and Podiatry Physical Therapy

• Biomechanics of Foot

• Foot Orthotic Therapy

Podiatry Physical Therapy– Example I: pronated foot– Example II: one pronated and another supinated

Podiatry Physical Therapy

• Podi = foot

• DPT: one kind of physical therapy intervention to assess, treat, and prevent foot and ankle problems– movement – manual– modality– assistive device

– podiatrist (DPM) vs. certified pedothist (CPED)

Indications of Podiatry PT

• utilization of functional foot orthosis as a component of the total treatment program for– back and hip pain related to foot dysfunction– patellofemoral syndrome– shin splint– plantar fasciitis– foot sprain or deformities– heel pad syndrome– ……

Case #1

• A 22 year-old male was unable to stand longer than 10 minutes. He felt lateral knee pain during walking.

• diagnosis: severe pronated feet due to forefoot varus

• prescription: functional foot orthoses with forefoot medial postings

• pain decreases immediately

• changes orthoses every 3-4 yrs

Case #2• A 38 year-old male stands with one foot pronated

and another foot supinated. His chief complaints are low back and currently treated by PT.

natural stance stance c/ pelvis leveled

柴惠敏hmchai@ntu.edu.twhttp://www.pt.ntu.edu.tw/hmchai/