Foot and Ankle

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Chapter 8

Foot and Ankle

Joseph S. Park, Venkat Perumal

Foot and Ankle

General Guidelines

Preoperative antibiotics are given half an hour before the incision is made

Placing a bump beneath the appropriate hip can facilitate access to the desired part of the foot/ankle, which is especially important when considering the sequence of multiple procedures: a bump beneath the ipsilateral hip allows access to the lateral calcaneus for medial displacement osteotomy and then is removed to allow external rotation and access to the posterior tibial tendon/medial ankle

A tourniquet is applied according to the surgeon’s preference

Careful dissection/cautery to maintain hemostasis may obviate the need for a tourniquet and prolonged ischemia; however, the need for clear visualization of neurovascular structures and during arthroscopy is critical, and a tourniquet should be used as necessary

An Esmarch bandage or pneumatic tourniquet may be used

All bony prominences should be adequately padded

Review the pertinent anatomy and mark the palpable landmarks

Regional Anatomy

Osteology

Arthrology

Ankle Joint (Figs. 8-5 to 8-7)

The ankle joint is a strong and stable joint

The ankle joint is a synovial hinge joint

A capsule encloses the joint and is attached to the bony articular margins

Ligaments

• Medial/deltoid ligament

• Lateral ligaments

• Anterior talofibular ligament

• Calcaneofibular ligament

• Posterior talofibular ligament

Nerve supply

• Deep peroneal and tibial nerve

Movements

• Dorsiflexion

• Plantar flexion

FIGURE 8-5 Ligaments of the hind foot—lateral view.

FIGURE 8-6 Ligaments of the hind foot—medial view.

FIGURE 8-7 A, Inferior view of the talus showing the interosseous ligament. B, Dorsal view of the hind foot (after removal of the talus) showing the calcaneal facets with the spring ligaments.

Subtalar Joint (see Figs. 8-5 to 8-7)

The subtalar joint is a plane synovial joint

A capsule attaches to articular margins of the talus and calcaneus

Ligaments

• Medial and lateral talocalcaneal ligaments

• Interosseous talocalcaneal ligament (the main support)

Movements

• Inversion

• Eversion

Talocalcaneonavicular Joint (see Figs. 8-5 to 8-7)

The talocalcaneonavicular joint is a synovial joint

A capsule incompletely encloses the joint

Ligaments

• Plantar calcaneonavicular ligament

Movements

• Gliding and rotatory movements

• Limited inversion and eversion

Calcaneocuboid (CC) Joint (Fig. 8-8)

The CC joint is a plane synovial joint

A capsule encloses the joint

Ligaments

• Bifurcated “Y” ligaments

• Long plantar ligament

• Short plantar ligament

Movements

• Limited inversion and eversion

FIGURE 8-8 Dorsal view of the ankle and foot.

Naviculocuneiform (see Fig. 8-8)

A synovial joint of gliding variety between the navicular and three cuneiforms

The capsule is reinforced by dorsal and plantar ligaments

The joint cavity is continuous with the intercuneiform, cuneocuboid, cuneometatarsal, and intermetatarsal joints

Naviculocuboid (see Fig. 8-8)

A fibrous joint

The dorsal, plantar, and interosseous ligaments reinforce joint stability

Intercuneiform and Cuneocuboid (see Fig. 8-8)

Plane synovial joints

Stabilized by the dorsal, plantar, and interosseous ligaments

The joint cavity communicates with the cavity of the cuneonavicular joint

The cuneocuboid joint is syndesmosis

Tarsometatarsal (Lisfranc Joint) and Intermetatarsal Joints (see Fig. 8-8)

Plane synovial joints

The tarsometatarsal joint of the great toe has a separate joint cavity

Stabilized by the dorsal, plantar, and interosseous ligaments

Movements

• Plantar flexion–dorsiflexion—first cuneometatarsal, fourth and fifth

• Rotation

Metatarsophalangeal (MTP) and Interphalangeal Joints (see Fig. 8-8)

MTP joints are condyloid joints

Stabilized by plantar plates and oblique collateral ligaments

Deep transverse ligaments connect all five MTP joints

The second toe is long axis, and adduction-abduction is performed by interossei

Interphalangeal joints are hinge joints

• Interphalangeal joints are stabilized by collateral ligaments and the capsular plantar ligament (fibrous plate)

• Interphalangeal joints only provide plantar flexion movement

Muscles

Extrinsic Muscles

Muscles are in the leg, but their tendons function within the foot

• Anterior compartment (innervated by the deep peroneal/anterior tibial nerve; Fig. 8-12)

• From medial to lateral: tibialis anterior (TA), extensor hallucis longus (EHL), extensor digitorum longus (EDL), and peroneus tertius

FIGURE 8-12 Muscles of the anterior compartment of the leg and dorsum of the foot.

• Lateral compartment (innervated by the superficial peroneal nerve; Fig. 8-13)

• Peroneus longus and brevis muscle

• Tendons descend together in a common tendon sheath underneath the superior peroneal retinaculum

FIGURE 8-13 The lateral/peroneal compartment of the leg.

• Posterior compartment (innervated by the posterior tibial nerve; Figs. 8-14 to 8-16)

• Superficial layer

• Triceps surae

• Deep layer

• Flexor digitorum longus (FDL)

• Tibialis posterior

• Flexor hallucis longus ( FHL)

FIGURE 8-14 The posterior compartment of the leg (gastrocnemius).

FIGURE 8-15 The posterior compartment of the leg (soleus).

FIGURE 8-16 The posterior compartment of the leg (deep layers).

• Functions

• Plantar flexors

• Triceps surae

• Tibialis posterior

• Assisted by the peroneals, FHL, and FDL

• Dorsiflexors

• TA

• Assisted by the EHL, EDL, and peroneus tertius

• Eversion

• Peroneus longus, brevis, and tertius

• Inversion

• TA and tibialis posterior

Intrinsic Muscles

Muscles that originate, insert, and function in the foot

• EDB

• Originates from the lateral aspect of the os calcis and the floor of the tarsal sinus and inserts into the lateral aspect of the extensor hood of the medial four toes; innervated by the deep peroneal nerve

Plantar intrinsic muscles lie in four layers

• First layer (Fig. 8-17)

• Abductor hallucis

• Flexor digitorum brevis

• Abductor digiti minimi

FIGURE 8-17 Muscles of the sole of the foot—first layer.

• Second layer (Fig. 8-18)

• FHL

• FDL

• Quadratus plantae

• Lumbricals

FIGURE 8-18 Muscles of the sole of the foot—second layer.

• Third layer (Fig. 8-19)

• Short intrinsic to great and small toes

• Flexor hallucis brevis

• Adductor hallucis

• Flexor digiti minimi brevis

FIGURE 8-19 Muscles of the sole of the foot—third layer.

• Fourth layer (Fig. 8-20)

• Interossei

• Insertion of the peroneus longus, tibialis anterior, and tibialis posterior

FIGURE 8-20 Muscles of the sole of the foot—fourth layer.

Nerves (Figs. 8-21 and 8-22)

Most innervations are of sciatic origin (except for the saphenous nerve)

The sciatic nerve separates near the apex of the popliteal fossa to the medial popliteal (tibial nerve) and the lateral popliteal (common peroneal nerve)

FIGURE 8-21 Cutaneous innervation of the leg and foot.

FIGURE 8-22 Deep innervation of the leg and sole.

Tibial Nerve

Medial sural cutaneous nerve

Medial plantar nerve

Lateral plantar nerve

Common Peroneal Nerve

Lateral sural cutaneous nerve

Superficial peroneal nerve

Medial branch of dorsal cutaneous nerve

Intermediate branch of dorsal cutaneous nerve

Deep peroneal (anterior tibial) nerve

• Dorsal digital nerves—adjacent sides of the first and second toes

Saphenous Nerve

The largest cutaneous branch of the femoral nerve

Follows the saphenous vein, supplying the medial side of the leg, the skin of the ankle, and further down along the medial side of the foot up to the base of the great toe

Sural Nerve

Formed by the union of the medial sural cutaneous nerve to the peroneal communicating branch of the lateral sural cutaneous nerve

Supplies the lower lateral side of the leg and the calcaneal branches to the heel; continues as the lateral dorsal cutaneous nerve, supplying the lateral side of the foot and little toe

Vascularity (Figs. 8-23 and 8-24)

The popliteal artery divides at the lower border of the popliteus muscle into the anterior and posterior tibial artery

FIGURE 8-23 The arterial system of the anterior leg and dorsum of the foot.

FIGURE 8-24 The arterial system of the posterior leg and sole of the foot.

Anterior Tibial Artery

Medial and lateral malleolar arteries

Dorsalis pedis artery

• Lateral tarsal artery

• Medial tarsal artery

• Arcuate artery—forms an arch at the base of the metatarsals

• First dorsal metatarsal artery

• Deep plantar artery

Posterior Tibial Artery

The peroneal artery arises 2 to 3 cm below the popliteus muscle

• Calcaneal

• Posterior lateral malleolar branches

• Perforating branch—to the artery of the tarsal sinus

Medial calcaneal branches

Medial plantar artery

The lateral plantar artery unites with the deep plantar branch of the dorsalis pedis to form the plantar arch

Blood Supply of the Talus (Figs. 8-25 and 8-26)

FIGURE 8-25 The arterial supply of the talus (distribution of blood supply).

FIGURE 8-26 The arterial supply of the talus (main source of blood supply).

Cross-Sectional Anatomy

Foot and Ankle

Lower tibia (Fig. 8-27)

FIGURE 8-27 Cross-sectional anatomy—lower third of the leg.

Ankle (Fig. 8-28)

FIGURE 8-28 Cross-sectional anatomy—ankle joint.

Foot (hind and mid parts; see Figs. 8-29 and 8-30)

FIGURE 8-29 Cross-sectional anatomy—hind foot.

FIGURE 8-30 Cross-sectional anatomy—mid foot.

Common Hazards (Figs. 8-31 to 8-33)

Medial neurovascular bundle

Anterior neurovascular bundle

Sural nerve

Dorsalis pedis artery

Surface Landmarks

Superficial bony landmarks (Figs. 8-34 and 8-35)

FIGURE 8-34 Superficial bony landmarks—dorsal view.

FIGURE 8-35 Superficial bony landmarks—posterior view.

Surgical Approaches to the Ankle

Anterior Approach to the Ankle (Video 8-1)

Indications

Ankle arthrotomy, fracture fixation, total ankle arthroplasty, and open treatment of osteochondral defects

Position (Fig. 8-36)

Supine

Place a bump under the ipsilateral hip to maintain neutral rotation of the leg

Use a calf or thigh tourniquet (depending on the procedure)

Partial exsanguination can allow better visualization of the neurovascular bundle

FIGURE 8-36 Positioning of the patient for surgery on dorsum of the foot.

Incision

Make a 15-cm incision over the anterior ankle

• Begin 10 cm proximal to the joint, lateral to the palpable TA tendon (Fig. 8-37)

FIGURE 8-37 Skin marking. A 10- to 15-cm longitudinal incision crossing the joint midway between the medial and lateral malleoli, ending on the dorsum of the foot.

• Cross the joint midway between the malleoli

• Dissect carefully in the distal aspect of the incision to avoid injury to the superficial peroneal nerve branches

• For total ankle arthroplasty, the interval between the TA and EHL is typically used; the interval between the EHL and EDL allows for direct visualization of the bundle and medial retraction of the neurovascular structures

Superficial Dissection (TA/EHL Interval)

Incise the deep fascia of the leg in line with the skin incision (Fig. 8-38)

• Incise the extensor retinaculum over the EHL, maintaining the sheath for the TA

• Retract the EHL laterally and incise the posterior aspect of the EHL sheath to visualize the ankle capsule (Fig. 8-39)

• The anterior tibial artery and deep peroneal nerve should be identified and protected lateral to this interval

FIGURE 8-38 Identify and protect the superficial peroneal nerve.

FIGURE 8-39 Cut the extensor retinaculum medial to the tibialis anterior tendon (desirable for exposure of the proximal tibia) or identify the plane between the extensor hallucis longus (EHL) tendon (medial) and the extensor digitorum longus tendon (lateral), the neurovascular bundle (deep peroneal nerve and anterior tibial artery) between them. Start a few centimeters above the ankle and dissect the bundle carefully distally as the EHL tendon crosses medially (this approach is desirable for distal extension to the dorsum of the foot).

Superficial Dissection (Alternative—EHL/EDL Interval)

Incise the deep fascia of the leg in line with the skin incision

Incise the extensor retinaculum

Find the plane between the EHL and EDL a few centimeters above the joint (Fig. 8-40)

FIGURE 8-40 The intramuscular plane between the tibialis anterior and extensor hallucis longus. n., Nerve.

Identify and mobilize the anterior tibial artery and deep peroneal nerve

Retract the EHL and neurovascular bundle medially and the EDL laterally

This approach allows for distal extension to approach the dorsal mid foot (Fig. 8-41)

FIGURE 8-41 Retract the extensor hallucis longus tendon.

Deep Dissection

Incise the capsule of the ankle joint in line with the incision (Fig. 8-42)

FIGURE 8-42 Incise the capsule of the ankle joint in line with the incision.

Expose the full width of the ankle joint by subperiosteal and subcapsular dissection of the tibia and talus (Fig. 8-43)

FIGURE 8-43 Retraction of the tendons exposes the overlying fat above the ankle joint capsule. Incise the capsule longitudinally to expose the width of the ankle joint.

Retractors should be placed on the periosteal layer to avoid excessive pressure on the skin or neurovascular bundle

Closure

Attempt to close the ankle capsule prior to layered closure; the extensor retinaculum should also be reapproximated to prevent bow-stringing of tendons