The KNEE, FOOT & ANKLE Dr. Shamay Ng 28 Jan 2019 Department of Rehabilitation Sciences The Hong Kong Polytechnic University Bones of Knee Joint 3 articulations: •Two femoro-tibial articulations •One femoro-patellar articulation Moore et al. (2018): Fig 7.86 (8th edition) Radiography of Knee Joint Moore et al. (2018): Fig 7.87 (8th edition) The Knee Joint • Composed of three bones: femur, tibia, patella • Hinge-type condylar synovial joint • Movements allowed: Flexion & extension Rotation around vertical axis (limited) Femoro-tibial Joint • 2 concave tibial plateaus • Medial plateau is larger surface area • Covered with fibrocartilaginous rings – menisci Medial meniscus: semicircular Lateral meniscus: nearly a complete ring Menisci • Medial – Attachments: Peripherally – by coronary ligament to tibial plateau Medially – attached to capsule and MCL Anterior horn – transverse ligament Menisci • Lateral – Attachments: Peripherally – by coronary ligament to tibial plateau Anterior horn – transverse ligament Menisci • Functions: Shock absorbers Improving congruency & contact area During movement: Rotations: menisci move with femur Flexion/extension: menisci move with tibia • Stability: Ligaments Collaterals – Medial Broad, fan-shaped ligament 10-12cm long Passes from medial epicondyle anteriorly to the medial tibia Superficial and deep portions Functions: 1. Resists excessive abduction of tibia on femur 2. Limits anterior translation of tibia on femur, and hyperextension • Stability: Ligaments Collaterals – Lateral Fibrous cord 5-6cms Lateral epicondyle and directed posterior to the fibular head No attachment of menisci Functions: 1. Resists varus stress during flexion/extension 2. Limits knee hyperextension Both collaterals help to limit external rotation of the tibia. • Stability: Ligaments Anterior Cruciate Starts at anterior tibia Passes superiorly, posteriorly and laterally Attaches to inner aspect of lateral femoral condyle (posteriorly) Function: Prevents anterior translation of tibia on femur Stability: Ligaments • Posterior Cruciate Starts at posterior intercondylar tibia Passes superiorly, anteriorly, and medially Attaches to inner aspect of medial femoral condyle Function: Resists posterior translation of the tibia on femur Both cruciates limit internal rotation of tibia on femur Menisci and Ligaments Patellar surface Ligaments that Stabilize the Knee Joint Posterior cruciate ligament Anterior cruciate ligament Tibial collateral ligament Lateral condyle Menisci Medial Fibular collateral ligament Cut tendon of biceps femoris muscle Medial condyle Tibia Lateral Fibula Deep anterior view, flexed Martini 10th Edition Dynamic Movement: Muscles • Extension: Quadriceps femoris • Flexion: Hamstrings • Special Function: Unlocking Popliteus Locking/Unlocking Mechanism • The two condyles are not the same length in the AP direction • When reaching final extension (in OPEN CHAIN) the lateral condyle ‘locks in’ to the tibia first • Then in order for the medial condyle to reach the same position, tibia has to rotate laterally a little bit Both plateaus moving together Lateral condyle locked in, so medial plateau must continue forward Lateral rotation of tibia in the last 20 degrees Therefore, when in full extension = locked To unlock, must medially rotate the tibia - popliteus muscle accomplishes this Capsule • Common to both tibiofemoral and patellofemoral joints • Surrounds joints like a tube with a hole anteriorly for patella • Lax structure • Statically stabilized by ligamentous structures • Dynamically stabilized by muscle tendons Quadriceps tendon Patella Joint capsule Synovial membrane Femur Bursa Fat pad Joint cavity Articular cartilage Accessory Structures of a Knee Joint Meniscus Tibia Ligaments Extracapsular ligament (patellar) Intracapsular ligament (cruciate) Knee joint, sagittal section Martini 10th Edition Patellar Retinacula • Fibrous expansions of the vastus medialis and lateralis muscles • Retinacula extends distally towards tibial plateaus & posteriorly to collateral ligaments • Laterally, the retinaculum contains expansion of the ITB Patellofemoral Joint • Femur – Anterior surfaces of femoral condyles and femoral sulcus (intercondylar groove) – Steep lateral condyle prevents lateral dislocation of patella • Patella ‒ Medial and lateral facets divided by a vertical ridge ‒ Odd facet (most medial aspect) Patellofemoral Joint • Stability Longitudinally: Quadriceps tendon superiorly Patella tendon inferiorly Transversely: Medial and lateral patellar retinaculae (indirectly VM & VL) Patellofemoral Joint Movement: Full extension: no contact between femur & patella 10-90° of flexion both facets in contact 90-135° gradually less medial facet contact until only lateral/odd 135° Arterial Anastomoses Around Knee • Genicular anastomosis (genu=knee) Branches of femoral, popliteal, anterior/posterior tibial arteries Moore et al. (2018): Fig 7.53 (8th edition) Popliteal Fossa Moore et al. (2018): Fig 7.50 (8th edition) Arteries of Leg and Foot Moore et al. (2018): Fig 7.59 (8th edition) Nerves of Leg and Foot Moore et al. (2018): Fig 7.58 (8th edition) Superficial Venous Drainage of Lower Limb Femoral triangle Long (Great) Saphenous vein Popliteal fossa Short (Small) Saphenous vein Ankle and Foot Bones of the Foot tarsal bones (7) metatarsal bones (5) Phalanges (14) Moore et al. (2018): Fig 7.12 (A) (8th edition) Tarsal Bones Moore et al. (2018): Fig 7.12 (D & E) (8th edition) Ankle joint • Hinge type of synovial joint • Proximal – Distal ends of tibia + fibula + inferior transverse part of the posterior tibiofibular ligament mortise (deep socket) • Distal – Trochlea (L. pulley) of the talus Fibrous Capsule of Ankle joint • Fibrous capsule – Thin anteriorly and posteriorly – Lateral collateral ligament • Anterior talofibular ligament • Posterior talofibular ligament • Calcaneofibular ligaments Moore et al. (2018): 7.99 (A) (8th edition) Ankle joint • Medial collateral ligament Deltoid ligament Moore et al. (2018): Fig 7.100 (8th edition) Talocrural (ankle) Joint • Movements of the ankle joint Dorsiflexion Plantarflexion Joints of Foot • • • • • • • • Subtalar joint Talocalcaneonavicular Calcaneocuboid Cuneonavicular Tarsometatarsal Intermetatarsal Metatarso-phalangeal Interphalangeal Moore et al. (2018): Fig 7.101 (8th edition) Transverse Tarsal Joints Moore et al. (2018): Fig 7.12 (A & B) (8th edition) Transverse Tarsal & Subtalar Joints • Transverse tarsal joint Calcaneocuboid and talonavicular joints • Subtalar joint Between talus and calcaneus • Inversion and eversion take place in these joints Ligaments of the Foot • Plantar calcaneonavicular ligament (spring ligament) Connects sustentaculum tali to the posteroinferior surface of the navicular Moore et al. (2018): Fig 7.103 (B) (8th edition) Ligaments of the Foot •Long plantar ligament From plantar surface of the calcaneus to groove on the cuboid, bases of metatarsals Important in maintaining the arches of the foot • Plantar calcaneocuboid ligament (short plantar ligament) Deep to the long plantar ligament From anterior aspect of the inferior surface of the calcaneus to inferior surface of the cuboid Moore et al. (2018): Fig 7.103 (A & B) (8th edition) Arteries of Foot Moore et al. (2018): Fig. 7.75 (8th edition) Nerves of Foot Foot Arches & Weight-Bearing Areas of Foot Moore et al. (2018): Fig. 7.104 (8th edition) Transverse Arch Metatarsals 1-5, Cuneiform 1-3, Cuboid Moore et al. (2018): Fig. 7.105 (A) (8th edition) Longitudinal Arches Medial: MT 1-3, Cuneiform 1-3, Navicular Talus & Calcaneus Lateral: MT 4 -5, Cuboid & Calcaneus Moore et al. (2018): Fig. 7.105 (A & B) (8th edition) Mechanisms of Arch Support Shape of stones: “keystone” Staples: ligaments Tie beam: tendons Suspension bridge: muscles Example: Active and Passive Support of Medial Longitudinal Support Moore et al. (2018): Fig. 7.105 (C) (8th edition) MUSCLES 4 Layers on the bottom of the foot: 1. Abductor digiti minimi, flexor digitorum brevis, abductor hallucis 2. FHL, FDL, four lumbricals, quadratus plantae 3. Flexor digiti minimi brevis, adductor hallucis, flexor hallucis brevis 4. Plantar & dorsal interossei, tendons of peroneus longus & tibialis posterior Four Layers of Plantar Muscles Moore et al. (2018): Fig. 7.71 (8th edition) Nerves of Foot • Adductor Hallucis* • Quadratus Plantae • Abductor digiti minimi • Lumbricals (2 lateral) • Flexor Digiti Minimi Brevis • Interossei Nerves of Foot •Abductor Hallucis •FDB •Lumbricals (2 medial) •Flexor Hallucis Brevis Clinical Implications Unhappy Triad of Knee Injuries Moore et al. (2018): B7.34 (8th edition) • TCL attach firmly to medial meniscus • Tearing of TCL frequently results in concomitant tearing of the medial meniscus and ACL = “Unhappy triad” Anterior & Posterior Drawer Sign Anterior drawer sign • Tibia slide anteriorly under femur • Tested via Lachman test Posterior drawer sign • Tibia slide posteriorly under femur Moore et al. (2018): B 7.34 (8th edition) Ankle Sprain • Mostly ankle inversion injury • Twisting of the weight- bearing, plantarflexed feet • Lateral collateral ligament (anterior talofibular ligament) is most commonly injured Moore et al. (2018): B7.40 (8th edition) Pott Fracture-Dislocation of Ankle • Forcefully everted foot • Pull strong on medial ligament results in medial malleolus fracture • Break the fibula superior to the tibiofibular syndesmosis Moore et al. (2018): B7.41 (8th edition) Palpation of Dorsalis Pedis Pulse • Lateral to the EHL tendons • Absence of pulse suggests vascular insufficiency resulting from arterial disease Moore et al. (2018): B7.28 (8th edition) Palpation of Posterior Tibial Pulse • Between the posterior surface of the medial malleolus and the medial border of the calcaneal tendon Moore et al. (2018): B7.26 (8th edition) Calcaneal Tendon Jerk • Normal result: plantarflexion • Tests the S1 and S2 nerve roots Moore et al. (2018): B7.23 (8th edition) Plantar Fasciitis • Inflammation of the plantar fascia Overuse from running and high-impact aerobics Inappropriate footwear • Pain on the plantar surface of the foot and heel Moore et al. (2018): B7.27 (8th edition) Calcaneal Bursitis • Inflammation of the deep bursa of the calcaneal tendon • Pain posterior to the heel • Caused by excessive friction on the bursa as the tendon continuously slides over it Moore et al. (2018): B7.24 (8th edition) Hallux Valgus L : Lateral deviation By pressure from footwear and degenerative joint disease Moore et al. (2018): B.7.42 (8th edition) Hammer Toe & Claw Toes Hammer toe • Proximal phalanx dorsiflexed at the metatarsophalangeal joint • Middle phalanx plantarflexed at the proximal interphalanged joint • Hyperextended distal phalanx Claw toes • Hyper extension of the metatarsophalanged joints • Flexion of the distal interphalangeal joints of lateral 4 toes Moore et al. (2018): B7.43 (A & B) (8th edition) • Flexible: Pes Planus (Flat Feet) flat when weight-bearing but normal when no weight More common, from degenerated intrinsic ligaments • Rigid: flat with or without weight Moore et al. (2018): B7.43 (C & D) (8th edition) Injury of Common Fibular Nerve & Footdrop • Toes fail to clear the ground during the swing phase • Causes: injury of the common fibular nerve Flaccid paralysis of all dorsiflexors and evertors Moore et al. (2018): B7.21 (8th edition) Injury of Common Fibular Nerve & Footdrop Compensations for “Footdrop”: (D) Steppage gait • Extra flexion at hip and knee to raise the foot (B) Waddling gait • Leans to the side opposite the long limb (C) Swing-out gait • Long limb abducted to allow the toes to clear the ground Moore et al. (2018): B7.21 (8th edition) The End Any Questions?