Biomechanics of F t and Podiatry Physical Therapy Huei-Ming Chai, PT PhD School of Physical Therapy National Taiwan University, Taipei, Taiwan June 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

Plantigrade planta = sole gradi = walk bipedal quadripedal 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 1 st metatarsal phalanx 1 st cuneiform MT head

Superior Aspect of Foot calcaneus talus navicular metatarsals phalanges Forefoot Midfoot Rearfoot cuneiforms cuboid midtarsal joint

fibula talus tibia mediallateral Anterior Aspect of Foot subtalar joint calcaneus 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 line plantar surface of MTHs

Pronated Foot ( 內旋足 ) non-weight-bearing weight bearing forefoot varus STJ pronated (plantigrade) Talus shifts medially + 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 WB stance

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 STJ supinated (plantigrade) Talus shifts laterally + 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 line plantar 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 lift metatarsal 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