5
Foot and Ankle
Anatomy of the Ankle and Foot
Anatomy of the Ankle: Key Points
Bony Anatomy
| 1. | What is more proximal: the medial or lateral malleolus? | 1. | Medial malleolus is more proximal A line drawn from medial to lateral malleolus is at an 8 degree angle to the horizontal |
| 2. | Is the center of ankle rotation externally or internally rotated? | 2. | 23 degrees externally rotated |
| 3. | With which direction of fibular motion is ankle dorsiflexion associated? | 3. | External rotation |
Muscular Anatomy
| 4. | What peroneal tendon hugs the fibula? | 4. | Peroneus brevis |
| 5. | What peroneal tendon has a more distal muscle belly? | 5. | Peroneus brevis |
| 6. | The os peroneum lies within what peroneal tendon? | 6. | Peroneus longus |
| 7. | What peroneal tendon attaches to the base of the fifth metatarsal? | 7. | Peroneus brevis |
| 8. | The groove within the talar body houses what tendon? | 8. | Flexor hallucis longus (FHL) |
| 9. | What structure is found lateral to the flexor hallucis longus tendon? | 9. | Os trigonum |
| 10. | The groove within the calcaneus houses what tendon? | 10. | The FHL coursing underneath the sustentaculum tali |
| 11. | What ligament is found in close proximity? | 11. | Calcaneonavicular (spring) ligament |
| 12. | The groove within the cuboid houses what tendon? | 12. | Peroneus longus |
| 13. | What is the associated syndrome at this location? | 13. | POPS (painful os peroneum syndrome) |
| 14. | What tendon inserts on the navicular? | 14. | Posterior tibial tendon |
| 15. | This insertion must be repaired after what surgical procedure? | 15. | Resection of an accessory navicular |
Ligamentous Anatomy
| 16. | What are the four components of the distal tibiofibular (tib-fib) joint? | 16. | Anterior inferior tib-fib ligament (AITFL) Posterior inferior tib-fib ligament (PITFL) Interosseous ligament (IO) Transverse ligament |
| 17. | The AITFL is most commonly involved in what two types of injuries? | 17. | Syndesmotic injuries Tillaux fractures |
| 18. | What is the clinical significance of the PITFL? | 18. | Attached to the posterior malleolar fracture fragment in a trimalleolar fracture |
| 19. | What are the two components of the superficial deltoid ligament? | 19. | Tibionavicular Tibiocalcaneal |
| 20. | What are the two components of the deep deltoid ligament? | 20. | Anterior tibiotalar Posterior tibiotalar |
| 21. | What is the clinical significance of the deep deltoid ligament? | 21. | Primary restraint to anterolateral talar displacement |
| 22. | What deep deltoid component exhibits hypertrophy with recurrent ankle sprains? | 22. | Anterior tibiotalar |
Surgical Anatomy
| 23. | What is the interval for the anterior approach to the ankle? | 23. | Between extensor hallucis longus (EHL) and extensor digitorum longus (EDL) |
| 24. | What structure must be identified and protected with this approach? | 24. | Superficial peroneal nerve (SPN) |
| 25. | Where does the sural nerve generally cross the Achilles tendon? | 25. | 10 cm proximal to the insertion |
Physical Examination
| 26. | In what position should the foot be placed when testing the posterior tibial tendon (PTT)? | 26. | Eversion Plantar flexion |
| 27. | In what position should the foot be placed when testing the calcaneofibular ligament? | 27. | Inversion Dorsiflexion |
| 28. | In what position should the foot be placed when testing the anterior talofibular ligament (ATFL)? | 28. | Plantar flexion Perform anterior drawer test |
| 29. | In what position should the foot be placed when testing for subluxing peroneal tendons? | 29. | Dorsiflexion Eversion |
Anatomy of the Foot: Muscular and Nervous Anatomy
Layers of the Plantar Foot
| 30. | What muscle layers are considered intrinsic? | 30. | 1 |
| 3 | |||
| 31. | What muscle layers are considered extrinsic? | 31. | 2 |
| 4 | |||
| 32. | Layer 1: what are the three components of the musculature and what is their innervation? | 32. | Abductor hallucis (medial plantar nerve [MPN]) Flexor digitorum brevis (MPN) Abductor digiti minimi (lateral plantar nerve [LPN]) |
| 33. | Layer 2: what are the four components of the musculature and what is their innervation? | 33. | Quadratus plantae (LPN) Lumbricals (MPN, LPN) Flexor digitorum longus (tibial nerve) Flexor hallucis longus (tibial nerve) |
| 34. | Layer 3: what are the three components of the musculature and what is their innervation? | 34. | Flexor hallucis brevis (MPN) Adductor hallucis (LPN) Flexor digit minimi brevis (LPN) |
| 35. | Layer 4: what are the four components of the musculature and what is their innervation? | 35. | Dorsal interosseous muscles (LPN) Plantar interosseous muscles (LPN) Peroneus longus (superficial peroneal nerve) Posterior tibialis (tibial nerve) |
| 36. | In what layer and at what locations do the medial and lateral plantar nerves lie? | 36. | Layer 2 MPN lies deep to the abductor hallucis muscle LPN lies deep to the quadratus plantae muscle |
| 37. | What is the significance of the extensor digitorum brevis (EDB)? What is its innervation? | 37. | Dorsal intrinsic muscle Innervated by the deep peroneal nerve |
| 38. | What is the origin of the flexor digitorum brevis (FDB)? | 38. | Medial calcaneal tubercle |
| 39. | What is the insertion of the FDB? | 39. | Middle phalanges |
| 40. | What is the origin of the plantar aponeurosis? | 40. | Plantar medial calcaneus |
| 41. | Where does the plantar aponeurosis insert? | 41. | Toe flexors |
| 42. | What are the three main functions of the aponeurosis? | 42. | Increase arch height as toes dorsiflex Major support of medial longitudinal arch Aid hindfoot inversion |
| 43. | What is the effect of hindfoot inversion on the transverse tarsal joints? | 43. | Hindfoot inversion locks the transverse tarsal joints |
| 44. | What nerve provides sensation to the dorsomedial great toe? | 44. | Dorsomedial cutaneous branch of superficial peroneal nerve (SPN) |
| 45. | This nerve runs across what structure? | 45. | Extensor hallucis longus (EHL) |
Surgical Approaches to the Foot
| 46. | What is the interval for the lateral approach to the hindfoot? | 46. | Between peroneus tertius (deep peroneal nerve) and peroneus brevis (SPN) |
| 47. | What structure must be reflected with this approach? | 47. | Extensor digitorum brevis (EDB) |
| 48. | What deeper structure must be identified and protected? | 48. | Flexor hallucis longus (FHL) |
| 49. | What structure must be released for the anterolateral approach to the midfoot? | 49. | EDB |
| 50. | What deeper structure must be identified and protected with this approach? | 50. | Spring ligament |
Anatomy of the Foot: Vascular Anatomy
| 51. | What two arteries comprise the major vascular supply to the foot? | 51. | Dorsalis pedis (especially the dorsum of the foot) Posterior tibial artery |
| 52. | What is the main branch of the dorsalis pedis and where is it found? | 52. | Deep plantar artery Between the first and second metatarsals |
| 53. | What are the two major branches of the posterior tibial artery? | 53. | Medial plantar artery Lateral plantar artery |
| 54. | Together, the deep plantar artery and the lateral plantar artery form what structure? | 54. | Plantar arch |
| 55. | In what layer of the foot is the plantar arch found? | 55. | 4th |
| 56. | Dorsal ulceration and weak pulses are suggestive of what clinical problem? | 56. | Arterial insufficiency |
Vascular Supply to the Talus
| 57. | The artery of the tarsal canal is principally supplied by what? | 57. | Posterior tibial artery |
| 58. | What region of the talus does it supply? | 58. | Body |
| 59. | Then it contributes to what artery? | 59. | Deltoid artery |
| 60. | What does the deltoid artery supply? | 60. | Medial one third of the talus |
| 61. | Disruption of the deltoid artery is associated with what delayed complication? | 61. | Varus collapse of the talus |
| 62. | The artery of the tarsal sinus is principally supplied by what two entities? | 62. | Dorsalis pedis Peroneal artery |
| 63. | What two regions of the talus does it supply? | 63. | Head and neck (antegrade) Body (retrograde) |
The Gait Cycle
Normal Gait
| 64. | What percentage of the gait cycle does the stance phase comprise? | 64. | 60% |
| 65. | What are the three divisions of the stance phase? | 65. | Heel strike Foot flat Toe off |
| 66. | What is the position of the hindfoot at heel strike? | 66. | Inverted |
| 67. | What is the position of the hindfoot at foot flat? | 67. | Everted (subtalar joint unlocked) |
| 68. | What is the position of the hindfoot at toe off? | 68. | Inverted |
| 69. | What is the principal invertor of the subtalar joint? | 69. | Posterior tibial tendon |
| 70. | What effect does subtalar inversion have on the talus? | 70. | Talus externally rotates |
| 71. | What effect does subtalar inversion have on the tibia? | 71. | Tibia externally rotates |
| 72. | Most gait cycle muscle activity is of what type? | 72. | Eccentric |
| 73. | What is the principal muscle activity during heel strike? | 73. | Tibialis anterior (TA) eccentric contraction (controlled plantar flexion) |
| 74. | What is the principal muscle activity during foot flat? | 74. | Gastrocnemius eccentric contraction (controlled dorsiflexion) |
| 75. | What is the principal muscle activity during toe off? | 75. | Gastrocnemius concentric contraction (active plantar flexion) |
| 76. | Where is the normal center of pressure at heel strike? | 76. | Heel pressure |
| 77. | Where is the normal center of pressure at foot flat? | 77. | Second metatarsal head |
| 78. | Where is the normal center of pressure at toe off? | 78. | Toes |
Deviations from Normal Gait
| 79. | How does hallux valgus alter the pressure distribution in foot flat? | 79. | Hallux bears less weight than predicted Center of pressure moves laterally |
| 80. | In what two ways does hallux valgus alter the pressure distribution in toe off? | 80. | Increases pressure centrally from medial to lateral Unloads toes |
| 81. | What are the two characteristics of an antalgic (painful) gait pattern? | 81. | Shorter stance on the painful side Contralateral swing phase more rapid |
| 82. | What is the gait pattern of a patient with an absent anterior cruciate ligament (ACL) called? | 82. | Quadriceps avoidance gait |
Pathologic States
Cavus Foot and Associated Conditions
| 83. | What fraction of cavus feet is idiopathic? | 83. | One third |
| 84. | What four disorders comprise the major differential diagnosis for the remaining two thirds? | 84. | Charcot-Marie-Tooth Tethered cord/other spine condition Friedreich’s ataxia Dejerine-Sottas (and others) |
Charcot-Marie-Tooth (CMT)
| 85. | What are the two major types of CMT? | 85. | I: hands also involved |
| II: early onset, associated with axonal atrophy | |||
| 86. | What type is generally autosomal recessive? | 86. | II |
| 87. | If family CMT inheritance pattern is autosomal dominant (AD), what chromosome may be responsible? | 87. | Chromosome 17 |
| 88. | What gene? | 88. | PMP22 |
| 89. | What is the resulting defect? | 89. | Abnormal myelin production |
| 90. | PMP22 abnormalities may also affect production of what substance? | 90. | Connexin |
| 91. | In which gender is CMT generally more common? | 91. | Male |
| 92. | In which gender is CMT generally more severe? | 92. | Female |
| 93. | Is CMT associated with sensory loss? | 93. | Sensory and proprioceptive losses may be present; it is variable |
| 94. | What are the four clinical findings of CMT foot? | 94. | Cavus foot Plantarflexed first ray Hindfoot varus Claw toes |
| 95. | With CMT, what is the relative muscle strength of the tibialis anterior? | 95. | Weak |
| 96. | … of the peroneus brevis? | 96. | Weak |
| 97. | … of the peroneus longus? | 97. | Strong |
| 98. | … of the intrinsics? | 98. | Weak |
| 99. | What is the net result of this relative muscle imbalance? | 99. | Plantarflexed first ray |
| 100. | What clinical test can reliably differentiate fixed and flexible hindfoot deformity? | 100. | Coleman block test |
| 101. | In general, what is the first-line treatment for most CMT patients (especially adolescents)? | 101. | Trial of bracing |
| 102. | If bracing is unsuccessful, what are the two general surgical principles for the patient with supple hindfoot deformity? | 102. | Forefoot corrective procedures alone usually suffice May consider adding calcaneal slide/osteotomy to protect soft tissue transfers |
| 103. | Specifically, surgery includes what five procedures? | 103. | Plantar fascia release Dorsiflexion osteotomy of the first ray Peroneus longus to peroneus brevis transfer Achilles tendon lengthening Possible calcaneal slide/osteotomy (to protect soft tissue transfer) |
| 104. | One might also consider performing the Jones procedure: what two components does it include? | 104. | Transfer of EHL to first metatarsal neck Fusion of the first interphalangeal (IP) joint |
| 105. | How might a Jones procedure be beneficial? | 105. | Helps a weak tibialis anterior with dorsiflexion of the first ray |
| 106. | In general, what is the surgical principle if the hindfoot deformity is fixed? | 106. | Must include calcaneal osteotomy for correction |
| 107. | What surgical option exists for a patient with fixed hindfoot deformity and degenerative changes? | 107. | Triple arthrodesis |
| 108. | What is an important caveat in this population? Why? | 108. | Triple arthrodesis is a procedure of last resort Poor outcomes have been reported in CMT patients |
| 109. | What two other musculoskeletal manifestations of CMT may be present? | 109. | Scoliosis Developmental hip dysplasia |
Calcaneocavus Foot
| 110. | A calcaneocavus foot is associated with what disease process? | 110. | Polio |
| 111. | Calcaneocavus deformity is due to the imbalance of what three muscles? | 111. | Weak gastrocnemius Strong tibialis anterior Strong posterior tibialis |
Hallux Valgus
| 112. | What is the primary stabilizer of the first metatarsophalangeal (MTP) joint? | 112. | Plantar plate |
| 113. | What is the range of normal for DMAA (distal metatarsal articular angle) | 113. | <15 degrees |
| 114. | What are the five components of the hallux valgus progression of events? | 114. | Valgus >15 degrees Abductor hallucis moves from medial to plantar Shifts adductor hallucis, flexor hallucis brevis, FHL laterally Sesamoids dislocate and fibular sesamoid falls into the first intermetatarsal space Deformity progresses |
| 115. | What are the intermetatarsal (IM) angle and the hallus valgus (HV) angle indications for soft tissue procedures alone? | 115. | IM angle <13 degrees HV angle <25 degrees |
| 116. | What are the IM angle and HV angle indications for a chevron osteotomy? | 116. | IM <13 degrees HV <30 degrees |
| 117. | What are the indications for a biplanar chevron? | 117. | DMAA >15 degrees |
| 118. | How much angular correction can a chevron achieve for every 1 mm of translation? | 118. | 1 degree |
| 119. | If a chevron osteotomy results in avascular necrosis, what is the salvage option? | 119. | Fusion |
| 120. | What are the IM angle and HV angle indications for MT shaft and proximal procedures? | 120. | IM <20 degrees HV <50 degrees |
| 121. | What are three examples of shaft and proximal osteotomies? | 121. | Scarf Ludloff Mau |
| 122. | In general, can greater correction be obtained with a shaft or with a proximal osteotomy? | 122. | Generally greater correction with proximal than with shaft |
| 123. | What are the IM angle and HV angle indications for a Lapidus procedure? | 123. | IM <20 degrees HV <50 degrees |
| 124. | In particular, the Lapidus is indicated for patients with what two characteristics? | 124. | Hypermobile Medially slanted surface at the metatarsocuneiform joint |
| 125. | What are the IM angle and HV angle indications for resection arthroplasty? | 125. | IM <13 degrees HV <45 degrees |
| 126. | For what patient population would a resection arthroplasty be a consideration? | 126. | Low-demand elderly patients |
| 127. | What is the most common complication of a metatarsal osteotomy? | 127. | Malunion, which leads to transfer metatarsalgia |
| 128. | Of all the hallux valgus procedures, which has the highest nonunion rate? | 128. | Tarso-metatarsal fusion |
Juvenile Hallux Valgus
| 129. | What patient population is particularly at risk for juvenile hallux valgus? | 129. | Females with generalized ligamentous laxity |
| 130. | With juvenile hallux valgus, in which position is the first metatarsal generally found? | 130. | Primus varus |
| 131. | How does the DMAA differ from normal? | 131. | Increased |
| 132. | What is a common associated finding at the IP joint? | 132. | Hallux interphalangeus |
| 133. | Juvenile HV usually requires what surgical procedure? | 133. | Single or double (corrects DMAA) osteotomy of the first metatarsal |
| 134. | At what age can these procedures be performed? | 134. | Once physes are closed |
| 135. | What is the treatment for severe deformity in a child with open physes? | 135. | First cuneiform opening wedge osteotomy |
Deformities of the Lesser Toes
Claw Toe
| 136. | Why does a claw toe develop in patients with Charcot-Marie-Tooth? | 136. | Flexor spasticity |
| 137. | Why does a claw toe develop in patients with head injury? | 137. | Extensor spasticity |
| 138. | Why does a claw toe develop in patients with no obvious pathologic cause? | 138. | Volar plate laxity |
| 139. | What is the most common cause leading to the development of volar plate laxity? | 139. | Second MTP joint synovitis |
| 140. | What are two common clinical signs of second MTP synovitis? | 140. | Swelling Positive drawer test |
| 141. | If caught at an early phase, what two treatment options are available? | 141. | Metatarsal bar Stiff shoe |
| 142. | If these conservative measures fail, what two treatment options are available? | 142. | Synovectomy Capsular reconstruction |
| 143. | Regardless of etiology, what is the sequence of five events that results in the clinical development of a claw toe? | 143. | Metatarsophalangeal joint extension Dorsal interosseous muscle subluxation Extensor digitorum longus hyperextends the MTP and cannot extend the proximal interphalangeal (PIP) joint or distal interphalangeal (DIP) joint Intrinsics slide dorsally and cannot flex the MTP Flexors flex the PIP and DIP |
| 144. | What are the three preferred treatments if the MTP joint is reducible? | 144. | Plantar plate release Collateral release Flexor to extensor tendon transfer |
| 145. | What is the preferred treatment if the MTP joint is irreducible? During this procedure, which structures must be preserved? | 145. | Weil osteotomy Must take care to preserve collaterals |
| 146. | What are the two primary complications associated with Weil procedures? | 146. | Recurrent dorsal contracture Floating toe (extended toe because intrinsics slip dorsally) |
| 147. | Are transfer lesions commonly associated with Weil procedures? | 147. | No, rarely |
| 148. | A claw toe associated with a mallet toe may result in which clinical deformity? | 148. | Crossover toe |
| 149. | What is the preferred treatment in that clinical situation? | 149. | Same as reducible/irreducible algorithm above |
| 150. | For isolated fifth toe clawing (cockup deformity), what is the preferred treatment? | 150. | Proximal phalangectomy (Ruiz-Mora procedure) |
Mallet Toe
| 151. | If conservative treatment of mallet toe fails, then which procedure is preferred at the joint? At flexor digitorum longus (FDL)? | 151. | DIP joint arthrodesis or arthroplasty FDL tenotomy |
Hammer Toe
| 152. | If conservative treatment of hammer toe fails, then which procedure is preferred at the joint? At FDL? | 152. | PIP arthrodesis or arthroplasty FDL flexor to extensor tendon transfer |
Curly (Underlapping) Toe
| 153. | What is the surgical treatment of choice for curly toe? | 153. | Flexor tenotomy |
Fifth Toe Bunionette
| 154. | What 4,5 intermetatarsal (IM) angle is considered normal? | 154. | 5 to 6 degrees |
| 155. | If a normal IM angle is present, what is the preferred treatment for fifth toe bunionette? | 155. | Lateral eminence resection |
| 156. | If IM angle is abnormal, how does the treatment differ? | 156. | Metatarsal osteotomy is required |
| 157. | What is the preferred fifth metatarsal osteotomy? | 157. | Oblique diaphyseal osteotomy |
| 158. | What type of metatarsal osteotomy must be avoided? | 158. | Proximal osteotomies |
| 159. | Quick review: Proximal osteotomies of the first metatarsal must be avoided in what patients? | 159. | Hallux valgus patients with open physes |
| 160. | What is the treatment of choice for a crossover fifth toe? | 160. | Proximal phalanx excision |
| 161. | In idiopathic plantar keratosis, a discrete callus is usually due to pressure from what structure? | 161. | Lateral condyle of metatarsal head |
Sesamoid Disorders and Related Conditions
| 162. | Sesamoiditis is associated with what clinical condition? | 162. | FHB tendonitis |
| 163. | Which sesamoid is most commonly injured? | 163. | Tibial sesamoid |
| 164. | Which sesamoid is most commonly bipartite? | 164. | Tibial (bipartite in 10%) |
| 165. | Compare the treatment of sesamoid fracture in an elite athlete versus general population. |
