Biomechanics of the Ankle and Foot PDF

Biomechanics of the ankle and foot Prof. Olga Hoyos López MSc PT  INTRODUCTION. FUNCTION: The ankle & foot provide a stable base while conforming to uneven surfaces Provides balance & stability Flexible → absorb stress and adapt t...

Biomechanics of the ankle and foot Prof. Olga Hoyos López MSc PT  INTRODUCTION. FUNCTION: The ankle & foot provide a stable base while conforming to uneven surfaces Provides balance & stability Flexible → absorb stress and adapt to the ground Rigid → withstand propulsive forces/push off Complex functional and structural interaction is possible between joints, connective tissues, and muscles. 2  INTRODUCTION. FUNCTION: It provides important protective and feedback measures to the muscles of the lower extremity Weight bearing during walking, running, standing Propulsion & power generation Allows positioning of foot 3  Tibiofibular joints The mortise adjust its position as the talus moves: – Proximal tibiofibular joint (PTFJ) Head of fibula with posterolateral aspect of tibia Plane joint Anterior and posterior proximal tibiofibular ligaments interosseous membrane – Distal tibiofibular joint (DTFJ) concave face (tibia) and convex face (fibula) Syndesmosis anterior and posterior distal tibiofibular ligaments Fibrous fat tissue connecting the tibia and fibula 4  Arthrokinematics of the tibiofibular joints A slight gliding motion in the PTFJ is possible during osteokinematics of the ankle and knee: – Dorsiflexion: cranial glide – plantar flexion: caudal glide – Knee Flexión: Forward Glide – Knee Extension: Posterior Glide 6 Arthrokinematics of the tibiofibular joints The trochlea of the talus is wider anteriorly than posteriorly. In the DTFJ: Dorsiflexion: separation plantar flexion: approximation 7  ANATOMY: ANKLE & FOOT Ankle → Talocrural Joint (tibia, fibula, and talus) Anatomical perspective: talocrural joint. Functional Perspective: + proximal and distal tibiofibular joint and interosseous membrane Foot → all tarsal bones and joints distal to the ankle. Reardfoot: talus, calcaneus, and subtalar joint. Midfoot: navicular, cuboid, 3 cuneiforms Forefoot: metatarsals and the phalanges, including all distal joints and including the tarsometatarsal joints. 8 9  Talocrural joint Mortise by medial malleolus and lateral malleolus (tibiofibular syndesmosis) – talus Hinge joint. 1dg freedom Rest position: 10° plantar flexion Compact position/close pack: maximal dorsiflexion Concave/convex rule: – Open kinetic chain: convex rule – Closed kinetic chain: concave rule 10 Osteokinematics of the talocrural joint Range of Osteokinematics motion Dorsiflexion 0-20/30dg Plantarflexion 0-50dg 11  Arthrokinematics of the talocrural joint Arthrokinematics Arthrokinematics osteokinematics (sliding) (rolling) Plantar flexion (OKC) Anterior (Talus) Posterior (Talus) Dorsi flexion (OKC) Posterior (Talus) Anterior (Talus) Plantar flexion (CKC) Posterior (mortise) Posterior (mortise) Dorsi flexion (CKC) Anterior (mortise) Anterior (mortise) 12  Arthrokinematics of the talocrural joint Arthrokinematics Arthrokinematics Osteokinematics SLIDE ROLL Plantar flexion Anterior (Talus) Posterior (Talus) (OKC) Dorsiflexion (OKC) Posterior (Talus) Anterior (Talus) Plantar flexion (CKC) Posterior (mortise) Posterior (mortise) Dorsiflexion (CKC) Anterior (mortise) Anterior (mortise) During Dorsiflexion in OKC, the dome of the talus is convex, and the distal tibia/fibula (mortise) is concave. Hence, CONCAVE RULE. -Talus (convex): anterior roll, posterior glide During Dorsiflexion in CKC, concave moves on convex. -Mortise (concave): anterior roll, anterior glide 13  Arthrokinematics of the talocrural joint Arthrokinematics Arthrokinematics Osteokinematics SLIDE ROLL Plantar flexion Anterior (Talus) Posterior (Talus) (OKC) Dorsiflexion (OKC) Posterior (Talus) Anterior (Talus) Plantar flexion (CKC) Posterior (mortise) Posterior (mortise) Dorsiflexion (CKC) Anterior (mortise) Anterior (mortise) 14  Talocrural joint stability Static stabilizers (Passive structures): – Mortise and Talar shape / Gravity / Capsule & Ligaments – Medial stability: Deltoid ligament Tibionavicular Tibiotalar Tibiocalcaneus – Lateral stability Anterior talofibular lig. Posterior talofibular lig. Calcaneofibular Lig. – Syndesmosis/tibiofibular ligaments Dynamic stabilizers: musculature 15  Kinetics: dorsiflexion & plantarflexion DORSIFLEXION PLANTAR FLEXION -Tibialis anterior! -Gastrocnemius Less stable in PF! -Extensor Digitorum Longus -Soleus -Extensor Hallucis Longus -Tibialis posterior -Peroneus longus & brevis -Plantaris -Flexor hallucis longus  Foot Anatomy Rearfoot: calcaneus, talus Midfoot: navicular, cuboid, 3 cuneiforms Forefoot: metatarsals and phalanges 18  Foot joints Joints Subtalar/talocalcaneal Mediotarsal (Chopart) – Talonavicular – Calcaneocuboid 5 tarso-metatarsal joints Cubonavicular, cuneonavicular… Functions: Orient the foot with respect to the 2 remaining axes in space Alters the shape and curvature of the plantar arches / Adapts to irregularities / Shock absorber 19  Subtalar / Talocalcaneal joint Talus on calcaneus. Synovial, gliding joint Calcaneus: largest, strongest, and most posterior bone of foot Three separate plane articulations between the talus superiorly, and the calcaneus inferiorly – Posterior – Medial – Anterior This geometry allows supination and pronation of the ankle Pronation: closed pack position. Allows foot to absorb shock during loading phase of gait Supination: loose pack position. Creates rigid lever (heel strike & toe off) of gait cycle 20 21  Subtalar joint stability Interosseus talocalcaneal Ligament (1,2) Lateral talocalcaneal Ligament (3) Posterior talocalcaneal Ligament (4) Medial talocalcaneal lig. These ligaments are all tensed in decompression, inversion, and eversion movements. 22 ankle osteokinematics  Osteokinematics of the subtalar joint Osteokinematics subtalar joint Oblique axis / Hence: pronation and supination: – Pronation → Dorsiflexion, Eversion and ABD (Lowering of the arch!) – Supination →Plantar flexion, Inversion and ADD (Elevation of the arch!) 24  Simplified arthrokinematics of the subtalar joint Arthrokinematics : – Posterior facet of calcaneus convex rule (OKC) – Anterior facet of calcaneus concave rule (OKC) arthrokinematics arthrokinematics (glide) Osteokinematics Anterior facet (Glide) Posterior facet Supination (OKC) Medial (Calcaneus) Lateral (Calcaneus) Pronation (OKC) Lateral (Calcaneus) Medial (Calcaneus) Supination (CKC) Lateral (Talus) Medial (Talus) Pronation (CKC) Medial(Talus) Lateral (Talus) https://www.youtube.com/watch?v=7SK_O-NuFr4 25 Talus Force distributor No muscular insertions 26  Midtarsal / Chopart`s Joint Talonavicular and calcaneocuboid joints Osteokinematics: Combined with subtalar joint, also contributes to: – Pronation – Supination – Simplified Arthrokinematics: Concave Rule (OKC) Gliding 27  Other tarsal Joints Cuneonavicular, intercuneiform and tarsometatarsal / Lisfrank joint – Plane joints – Adapt the curvature of plantar arches 28 Lisfranc complex / injury  INTERNAL ARCH (+ FLEXIBLE) FORMED: SUPPORT LIGAMENTS: – CALCANEUS plantar calcaneonavicular lig. – TALUS Interosseus talocalcaneal Lig – NAVICULAR SUPPORT MUSCLES: – MEDIAL CUNEIFROM Tibialis posterior – 1st METATARSAL Peroneus longus Flexor hallucis longus Abductor hallucis 30  EXTERNAL ARCH FORMED: – CALCANEUS – CUBOID – 5th METATARSAL SUPPORT LIGAMENT: plantar calcaneocuboid ligament SUPPORT MUSCLES: – Peroneus longus – Peroneus Brevis – Abductor digiti minimi 31  ANTERIOR ARCH FORMED BY: Metatarsals Heads SUPPORT LIGAMENTS: Intermetatarsal Ligament SUPPORT MUSCLES: Adductor hallucis 32 Metatarsophalangeal and interphalangeal Proximal (metatarsal:convex). Distal (phalanx: concave) CKC: convex rule // OKC: concave rule Most functional in CKC Artrhokinematic Artrhokinematic Osteokinematic (Glide) (roll) Flexion (OKC) Caudal (Phalanx) Caudal (Phalanx) Extension (OKC) Cranial (Phalanx) Cranial (Phalanx) Flexion (CKC) Cranial (Metatarsal) Caudal (Metatarsal) Extension (CKC) Caudal (Metatarsal) Cranial (Metatarsal) 33  PLANTAR VAULT FORMED BY 3 ARCHES:: Head 1st Metatarsal Bone Head 5th Metatarsal Bone CALCANEUS 34  Windlass Mechanism The plantar aponeurosis (fascia) acts similarly to a windlass mechanism. Extension 1st MTP →the plantar aponeurosis (fascia) is tightened Causes locking of the foot This action joins the metatarsal and tarsal bones making them a rigid structure and eventually raising the longitudinal arches. This function is important to provide a stiff lever for gear propulsion during the gait cycle 35 Ankle and foot pathology  Ankle and foot pathology Ligament sprains Fractures (stress) Plantar Fasciitis Tendinopathy: Achilles’, peroneal, tibialis post… Hallux valgus … 37