Podiatry

01 Foot & Ankle Anatomy

The foot and ankle constitute one of the most complex mechanical structures in the human body, containing 26 bones, 33 joints, 107 ligaments, and 19 intrinsic muscles, all working in concert to absorb shock, adapt to terrain, and provide a rigid lever for propulsion. A thorough understanding of this anatomy is the foundation of all podiatric diagnosis and treatment.

Bones of the Foot

The 26 bones are divided into three functional groups:

Hindfoot (2 bones) — The talus (trochlea articulates with the tibial plafond and malleoli, forming the ankle mortise; inferiorly articulates with calcaneus at the subtalar joint; anteriorly with navicular at the talonavicular joint) and the calcaneus (largest tarsal bone, bears the body’s weight in stance; posterior tuberosity receives the Achilles tendon insertion; sustentaculum tali supports the talar neck medially; anterior process articulates with cuboid). The calcaneus has a normal Bohler angle of 20–40°; loss of this angle suggests compression fracture.

Midfoot (5 bones) — The navicular (keystone of the medial longitudinal arch; receives posterior tibialis insertion at the navicular tuberosity; blood supply is tenuous, predisposing to AVN/Kohler disease), the cuboid (lateral column, contains the peroneus longus groove on its plantar surface), and three cuneiforms: medial (largest, articulates with 1st metatarsal), intermediate (smallest, articulates with 2nd metatarsal — this recessed mortise configuration is key to Lisfranc joint stability), and lateral (articulates with 3rd metatarsal).

Forefoot (19 bones) — Five metatarsals (1st metatarsal is the shortest and thickest, bears approximately one-third of forefoot load via its two sesamoids; the 2nd metatarsal is typically the longest and most common site of stress fracture; the 5th metatarsal base has three distinct fracture zones). Fourteen phalanges — the hallux has two (proximal and distal) while digits 2–5 each have three (proximal, middle, distal). Two sesamoid bones (tibial/medial and fibular/lateral) are embedded within the flexor hallucis brevis tendons plantar to the 1st MTP joint, functioning as a fulcrum and weight-bearing surface.

Joints

Ankle (talocrural) joint — a hinge (ginglymus) joint formed by the tibial plafond, medial malleolus, and lateral malleolus (fibula) articulating with the talar dome. Primary motion: dorsiflexion (~20°) and plantarflexion (~50°). The mortise is wider anteriorly, so the ankle is inherently more stable in dorsiflexion than in plantarflexion (where inversion sprains most commonly occur).

Subtalar joint — the articulation between the inferior talus and superior calcaneus, composed of three facets (anterior, middle, posterior). Primary motion: inversion/eversion (combined with rotation, this produces pronation and supination). The axis of the subtalar joint is oriented 42° from the transverse plane and 16° from the sagittal plane.

Midtarsal (Chopart) joint — comprises the talonavicular and calcaneocuboid joints; allows forefoot adaptation to terrain. Functions as a “torque converter” between hindfoot and forefoot. When the subtalar joint pronates, the midtarsal joint axes become parallel, unlocking the midfoot (flexible, shock-absorbing). With supination, the axes diverge, locking the midfoot into a rigid lever for push-off.

Tarsometatarsal (Lisfranc) joint — articulation of the three cuneiforms and cuboid with the metatarsal bases. The Lisfranc ligament connects the medial cuneiform to the 2nd metatarsal base; there is no intermetatarsal ligament between the 1st and 2nd metatarsals, making this the weak link.

MTP joints — condyloid joints allowing flexion/extension, abduction/adduction. The plantar plate is a thick fibrocartilaginous structure on the plantar aspect; attenuation leads to predislocation syndrome and crossover toe. IP joints — hinge joints; the hallux has one (IPJ), digits 2–5 have proximal (PIPJ) and distal (DIPJ) interphalangeal joints.

Ligaments

Lateral ligament complex — (1) Anterior talofibular ligament (ATFL): weakest of the three, taut in plantarflexion, first to rupture in inversion sprains; (2) Calcaneofibular ligament (CFL): taut in dorsiflexion, crosses both ankle and subtalar joints, second to tear; (3) Posterior talofibular ligament (PTFL): strongest lateral ligament, rarely torn in isolation.

Deltoid (medial) ligament — a fan-shaped ligament with superficial (tibionavicular, tibiocalcaneal, posterior tibiotalar) and deep (anterior tibiotalar, deep posterior tibiotalar) components. The deep deltoid is the primary restraint against lateral talar shift; injury indicates significant trauma (often associated with fibula fracture — Weber B/C).

Spring (plantar calcaneonavicular) ligament — connects the sustentaculum tali to the navicular; supports the talar head and the medial longitudinal arch. Attenuation is a hallmark of adult-acquired flatfoot (PTTD Stage II+). The Lisfranc ligament runs from the medial cuneiform to the 2nd metatarsal base; disruption causes tarsometatarsal instability.

Tendons

Achilles tendon — the strongest tendon in the body, formed by the confluence of the gastrocnemius and soleus (triceps surae). Inserts on the posterior calcaneal tuberosity. Blood supply is relatively poor 2–6 cm proximal to insertion (the “watershed zone”), which is the most common site of rupture. The Thompson test (squeezing the calf with the patient prone; absent plantarflexion = positive = rupture) is the key clinical exam.

Posterior tibial tendon — the primary dynamic stabilizer of the medial longitudinal arch. Courses behind the medial malleolus, inserts on the navicular tuberosity, medial cuneiform, and bases of metatarsals 2–4. Dysfunction produces adult-acquired flatfoot deformity (AAFD). Anterior tibial tendon — the primary dorsiflexor of the ankle; inserts on the medial cuneiform and 1st metatarsal base.

Peroneal tendons — the peroneus longus courses beneath the cuboid to insert on the 1st metatarsal base and medial cuneiform (stabilizes the 1st ray); the peroneus brevis inserts on the 5th metatarsal base (primary evertor). Both tendons pass behind the lateral malleolus in the peroneal groove, held by the superior peroneal retinaculum. Retinacular injury leads to peroneal subluxation.

Plantar Fascia

The plantar aponeurosis originates from the medial calcaneal tuberosity and fans distally to insert on the plantar plates and proximal phalanges of all five toes. It is the primary static support of the medial longitudinal arch. The windlass mechanism — dorsiflexion of the toes at the MTP joints tightens the plantar fascia, elevating the arch and converting the foot into a rigid lever for propulsion. This mechanism is tested clinically by dorsiflexing the hallux (Jack test).

Arches

Medial longitudinal arch — calcaneus → talus → navicular → cuneiforms → metatarsals 1–3. Highest arch; keystone = navicular. Supported by the spring ligament, posterior tibial tendon, and plantar fascia. Lateral longitudinal arch — calcaneus → cuboid → metatarsals 4–5. Lower, more rigid; keystone = cuboid. Transverse arch — formed by the cuneiforms and cuboid proximally and the metatarsal heads distally; the peroneus longus tendon and the deep transverse metatarsal ligament are critical supports.

Neurovascular Supply

Posterior tibial artery — passes behind the medial malleolus (palpable pulse point), enters the foot through the tarsal tunnel, and bifurcates into the medial and lateral plantar arteries. The lateral plantar artery forms the deep plantar arch (analogous to the hand). Dorsalis pedis artery — continuation of the anterior tibial artery on the dorsum of the foot, palpable between the 1st and 2nd metatarsal tendons. Assessment of both pulses is mandatory in diabetic foot evaluation.

Tibial nerve — passes through the tarsal tunnel (posterior to the medial malleolus) and divides into the medial plantar nerve (sensation to medial 3.5 digits and motor to intrinsic muscles — analogous to the median nerve in the hand) and the lateral plantar nerve (sensation to lateral 1.5 digits, motor to interossei and adductor hallucis — analogous to the ulnar nerve). Baxter nerve (first branch of the lateral plantar nerve) innervates the abductor digiti minimi and is a cause of chronic heel pain when entrapped.

Dermatomes — L4: medial foot and ankle; L5: dorsum of foot, 1st web space, lateral ankle; S1: lateral foot and sole, heel. The sural nerve (from S1-S2) supplies the lateral foot and is vulnerable during lateral ankle surgery. The superficial peroneal nerve (L5) supplies the dorsum of the foot except the 1st web space (deep peroneal nerve, L5).

02 Biomechanics & Gait Analysis

Gait analysis and lower-extremity biomechanics underpin diagnosis and treatment planning across podiatric medicine. Abnormal mechanics cause overuse injuries, deformity progression, and ulceration in the neuropathic foot.

The Gait Cycle

A complete gait cycle (stride) runs from one heel strike to the next heel strike of the same foot. It is divided into stance phase (~60% of the cycle) and swing phase (~40%). During walking, there is a period of double limb support at the beginning and end of stance; in running, a float phase replaces double support.

Pronation & Supination

Pronation is a triplanar motion consisting of calcaneal eversion, talar adduction, and talar plantarflexion. It unlocks the midtarsal joint, allowing the foot to adapt to uneven surfaces and absorb shock. Supination is the reverse: calcaneal inversion, talar abduction, and talar dorsiflexion. It locks the midfoot into a rigid lever for propulsion. Normal gait requires pronation at heel strike transitioning to supination by midstance–heel off.

Overpronation (excessive or prolonged pronation) is the single most common biomechanical abnormality seen in podiatric practice; it is associated with plantar fasciitis, posterior tibial tendon dysfunction, hallux valgus, medial tibial stress syndrome, and patellofemoral pain. Oversupination (underpronation) reduces shock absorption and is associated with lateral ankle instability, stress fractures, and peroneal tendinopathy.

Windlass Mechanism

Described by Hicks (1954): dorsiflexion of the MTP joints winds the plantar fascia around the metatarsal heads, shortening the distance between calcaneus and metatarsals, thereby raising the medial longitudinal arch, inverting the hindfoot, and externally rotating the leg. This converts the foot from a mobile adaptor to a rigid lever. Failure of the windlass mechanism (e.g., in hallux rigidus or plantar fascia rupture) impairs push-off efficiency.

Foot Types

Pes planus (flatfoot) — reduced or absent medial longitudinal arch; calcaneus everted (>6° valgus); associated with overpronation, PTTD, and medial column overload. Pes cavus — abnormally high arch; calcaneus inverted; rigid foot with poor shock absorption; associated with neurologic conditions (CMT, spinal dysraphism), lateral column overload, metatarsalgia, claw toes, and lateral ankle instability. Neutral foot — normal arch height, calcaneus near vertical (0–4° valgus); optimal mechanical alignment.

Angular Relationships (Radiographic)

Clinical Gait Assessment

A focused gait assessment in the podiatric office does not require expensive technology. The examiner observes the patient walking (barefoot and in shoes) from anterior, posterior, and lateral perspectives:

Posterior view — calcaneal alignment in stance (valgus vs. varus vs. neutral); too-many-toes sign; presence and timing of heel inversion during push-off; symmetry of step length and cadence. Lateral view — ankle dorsiflexion at initial contact; knee flexion at loading response; early heel rise (equinus); trunk lean (antalgic). Anterior view — foot progression angle (normally 10–15° external rotation); in-toeing or out-toeing patterns; abductory twist at toe-off (compensatory forefoot abduction seen in limitus/rigidus).

Pressure analysis — in-shoe or barefoot plantar pressure mapping (F-Scan, EMED) quantifies peak pressures under specific regions and identifies high-risk areas in the diabetic foot. Peak plantar pressures >200 kPa during walking identify sites at risk for ulceration. This technology also guides orthotic prescription by identifying areas that require offloading and verifying that the orthotic effectively redistributes pressure.

03 Terminology & Abbreviations

Core terminology used in clinical podiatric documentation. A comprehensive abbreviations list appears in Section 28.

Anatomic Planes & Motions

Dorsiflexion — movement toward the shin (ankle) or superior surface of the foot (toes). Plantarflexion — movement toward the sole. Inversion — sole turns medially. Eversion — sole turns laterally. Abduction — movement away from the midline of the foot (2nd ray). Adduction — movement toward the midline. Pronation — triplanar motion combining eversion, dorsiflexion, and abduction. Supination — triplanar motion combining inversion, plantarflexion, and adduction.

Positional & Structural Terms

Valgus — distal segment deviates laterally (e.g., hallux valgus, calcaneal valgus). Varus — distal segment deviates medially (e.g., rearfoot varus, metatarsus primus varus). Equinus — ankle plantarflexion or inability to dorsiflex past neutral; associated with forefoot overload and Achilles tightness. Calcaneus (as a deformity) — foot fixed in dorsiflexion. Rocker-bottom — midfoot plantar convexity, typically from Charcot collapse.

Deformity Terminology

Hallux abductovalgus — lateral deviation of the hallux with medial prominence of the 1st metatarsal head. Metatarsus primus varus — medial deviation of the 1st metatarsal shaft. Hallux rigidus — degenerative arthritis of the 1st MTP joint with limited dorsiflexion. Hallux limitus — functional or structural limitation of 1st MTP dorsiflexion (<65° normally required for gait). Digiti flexus — generic term for flexion contracture of a lesser toe (hammertoe, claw toe, mallet toe). Hallux malleus — flexion deformity at the hallux IPJ.

Metatarsalgia — general term for pain under the metatarsal heads; not a diagnosis but a symptom complex requiring identification of the specific cause (neuroma, plantar plate tear, stress fracture, IPK, sesamoiditis, synovitis). Tailor bunion (bunionette) — lateral prominence of the 5th metatarsal head with lateral deviation of the 5th toe; treated with wider footwear, padding, or distal 5th MT osteotomy if refractory.

Procedural Terminology

Osteotomy — surgical cutting of bone to realign, shorten, or lengthen. Arthrodesis — surgical fusion of a joint. Arthroplasty — reshaping or replacing a joint (resection arthroplasty removes bone; implant arthroplasty inserts a prosthesis). Exostectomy — removal of a bony prominence (exostosis). Tenotomy — surgical division of a tendon. Capsulotomy — incision into a joint capsule to release contracture or allow access. Matrixectomy — destruction or removal of the nail germinal matrix (chemical with phenol/NaOH, or surgical). Syndesmectomy — excision of a tarsal coalition.

04 Nail Disorders

Onychomycosis

Fungal nail infection affects approximately 10% of the general population and up to 50% of adults over age 70. The most common pattern is distal lateral subungual onychomycosis (DLSO), caused predominantly by dermatophytes (Trichophyton rubrum, T. mentagrophytes). Other patterns include white superficial onychomycosis (WSO), proximal subungual (PSO — consider immunosuppression if seen), endonyx, and total dystrophic onychomycosis.

Diagnosis — clinical suspicion should be confirmed before starting systemic therapy. KOH preparation: nail clippings dissolved in 10–20% KOH; fungal hyphae visualized under microscopy (sensitivity ~60%). Fungal culture: Sabouraud dextrose agar — identifies species (4–6 weeks). PAS staining of nail clippings: most sensitive single test (~90%). PCR-based assays are increasingly available.

Treatment:

Onychocryptosis (Ingrown Toenail)

The lateral nail border penetrates the periungual skin, causing pain, inflammation, and infection. Most commonly affects the hallux. Stages:

Subungual Hematoma

Blood collection beneath the nail plate from direct trauma. If <25% of the nail plate and the nail/margins are intact, simple trephination (heated paperclip or 18-gauge needle through the nail plate) provides immediate pain relief. If >50% involvement, nail disruption, or associated distal phalanx fracture, nail removal and nail bed repair should be considered.

Melanonychia

Longitudinal melanonychia (pigmented band) requires careful evaluation to exclude subungual melanoma. The ABCDEF rule guides biopsy decisions: Age (50–70 peak), African/Asian/Native American; Band width >3 mm, irregular borders, brown-black color; Change in band morphology; Digit most commonly involved (thumb/hallux); Extension of pigment to proximal or lateral nail fold (Hutchinson sign); Family/personal history of melanoma. Any suspicious lesion requires nail matrix biopsy (punch or excisional).

Other Nail Conditions

Onychogryphosis — ram’s horn nail; hypertrophic, curved nail plate; common in elderly; debridement or avulsion. Onycholysis — distal separation of nail from bed; differential includes psoriasis, trauma, fungal infection, thyroid disease. Pincer nail — transverse overcurvature causing pain; treatment with nail avulsion ± matrixectomy or nail brace.

Psoriatic Nail Disease

Nail involvement occurs in up to 80% of patients with psoriasis and in >90% of patients with psoriatic arthritis. Key nail findings: pitting (small, well-defined depressions in the nail plate from punctate psoriatic lesions in the nail matrix — the most common psoriatic nail finding); oil drop sign (translucent yellow-brown discoloration of the nail bed); subungual hyperkeratosis (scaling beneath the distal nail plate); onycholysis (distal separation, often with erythematous border); splinter hemorrhages (linear hemorrhages in the nail bed from damaged capillaries); crumbling/dystrophy (severe matrix disease). Treatment: topical corticosteroids (clobetasol in a nail lacquer vehicle), intralesional triamcinolone acetonide (5 mg/mL injected into the nail matrix/bed — painful; limit to 2–3 sessions), and systemic therapy for moderate-severe disease (biologics targeting TNF-alpha, IL-17, or IL-23 are effective for both skin and nail psoriasis). Nail psoriasis responds slowly; set expectations for 6–12 months of treatment before full response.

05 Skin Conditions of the Foot

Verrucae (Plantar Warts)

Caused by human papillomavirus (HPV), most commonly types 1, 2, 4, and 27. Present as well-circumscribed hyperkeratotic lesions on the plantar surface with interruption of skin lines, pinpoint bleeding on debridement (thrombosed capillaries), and pain with lateral compression (distinguishes from callus, which hurts with direct pressure).

Tinea Pedis (Athlete’s Foot)

Dermatophyte infection of the foot, most commonly Trichophyton rubrum. Three clinical patterns:

Interdigital (most common) — maceration, scaling, fissuring in web spaces (especially 4th web space). Moccasin type — chronic, diffuse hyperkeratosis and scaling of the sole, heel, and lateral foot (often bilateral); associated with toenail onychomycosis; may require oral therapy. Vesiculobullous (inflammatory) — pruritic vesicles and bullae, often on the arch or instep; may trigger id reaction (autoeczematization) on hands.

Treatment: Topical antifungals for interdigital/vesiculobullous types: terbinafine 1% cream BID × 2 weeks (most effective topical), clotrimazole 1% BID × 4 weeks, or butenafine 1% daily × 4 weeks. Moccasin type often requires oral terbinafine 250 mg daily × 2–4 weeks. Keep feet dry; moisture-wicking socks; treat shoes with antifungal powder or UV shoe sanitizer.

Xerosis & Fissures

Extremely dry skin of the feet is common in diabetic patients (autonomic neuropathy reduces sweating) and the elderly. Heel fissures can become deep, painful, and serve as a portal for infection in diabetic/immunocompromised patients. Treatment: urea-based creams (20–40% urea for hyperkeratotic skin, 10% for maintenance), emollients after bathing, debridement of callus borders, liquid cyanoacrylate skin protectant for deep fissures, avoidance of soaking (worsens dryness).

Contact Dermatitis of the Foot

Allergic contact dermatitis — delayed-type (Type IV) hypersensitivity reaction to shoe materials, adhesives, dyes, or topical medications. Common allergens: rubber accelerators (mercaptobenzothiazole, thiuram) in shoe soles and insoles, potassium dichromate in leather tanning, formaldehyde resins in shoe adhesives, and neomycin/bacitracin in topical antibiotics. Distribution pattern mirrors contact area: dorsum and sides of the foot suggest shoe allergy. Diagnosis: patch testing. Treatment: allergen avoidance, topical corticosteroids, identification of specific allergen for footwear counseling. Irritant contact dermatitis — non-immunologic reaction to friction, moisture, or chemical irritants (e.g., antiperspirant overuse); treatment: remove irritant, barrier creams, moisture management.

Hyperhidrosis

Excessive sweating of the feet predisposes to maceration, tinea, and pitted keratolysis (Corynebacterium-induced). Treatment: topical aluminum chloride 20% (Drysol) applied nightly to dry feet; iontophoresis (tap water with low-level electrical current, 20–30 min sessions 3×/week); onabotulinumtoxinA injection (100–200 units distributed across plantar surface — effective 6–9 months, painful injection); glycopyrrolate 1% topical; oral glycopyrrolate or oxybutynin for severe cases. Pitted keratolysis — clusters of superficial pits on weight-bearing sole; treat with topical erythromycin, clindamycin, or benzoyl peroxide.

06 Corns, Calluses & Keratotic Lesions

Hyperkeratotic lesions result from repetitive pressure and friction. Understanding the etiology is essential — treating the lesion without correcting the underlying biomechanical or structural cause guarantees recurrence.

Classification

Intractable Plantar Keratosis (IPK)

A discrete, painful callus beneath a metatarsal head that recurs despite conservative care. Caused by a prominent or plantarly displaced metatarsal head, metatarsal length abnormality, or loss of the transverse metatarsal arch. Treatment: regular debridement (scalpel #15 blade, enucleation of central core), accommodative padding (metatarsal pad placed proximal to MT head to redistribute pressure), custom orthotic with metatarsal offloading. Surgical options for refractory IPK include dorsiflexory metatarsal osteotomy (Weil osteotomy) or condylectomy.

Porokeratosis

A discrete keratotic lesion with a distinct peripheral ridge (cornoid lamella) on histology. Porokeratosis plantaris discreta presents as a well-circumscribed plantar lesion with a translucent core surrounded by a keratotic rim. Often misdiagnosed as a wart. Treatment: simple enucleation is usually curative; recurrence is uncommon (unlike IPK).

07 Hallux Valgus (Bunion)

Hallux valgus is the lateral deviation of the great toe at the first MTP joint, associated with medial deviation of the first metatarsal (metatarsus primus varus). It is the most common forefoot deformity, affecting approximately 23% of adults aged 18–65 and 36% of those over 65. Etiology is multifactorial: genetic predisposition, first ray hypermobility, ligamentous laxity, pes planus, constrictive footwear.

Radiographic Assessment

Weight-bearing AP and lateral radiographs are essential. Key angles:

Also assess: congruency of the MTP joint (congruent = no lateral subluxation of the proximal phalanx; incongruent = subluxed), sesamoid position (tibial sesamoid station 1–7), MTP joint arthrosis (hallux rigidus if dorsal osteophytes and limited ROM).

Surgical Procedures by Severity

AOFAS Hallux Metatarsophalangeal-Interphalangeal Score — a 100-point functional outcome score: Pain (40 points), Function (45 points: activity, footwear, MTP motion, IP motion, stability), Alignment (15 points). Though widely used, it has limitations as a patient-reported outcome measure and is being supplemented by the PROMIS Foot & Ankle module.

Conservative Management

Indicated for mild deformity, asymptomatic patients, or those who are poor surgical candidates. Footwear modification — wide toe box shoes that do not compress the forefoot; avoid pointed or high-heeled shoes. Bunion pads/shields — reduce friction over the medial eminence. Toe spacers — silicone interpositional device between the 1st and 2nd toes; provides symptomatic relief but does NOT correct the deformity. Orthotic therapy — custom orthotic with medial arch support to control pronation and reduce the deforming forces on the 1st ray; may slow progression in mild cases. Night splints — hold the hallux in a corrected position overnight; no evidence for long-term correction in adults but may provide symptomatic relief.

Surgical Complications

Recurrence — the most common reason for patient dissatisfaction; caused by inadequate IMA correction, failure to address 1st ray hypermobility, or progression of underlying biomechanical deformity. Hallux varus — overcorrection resulting in medial deviation of the hallux; may require revision surgery (extensor hallucis brevis transfer, soft tissue rebalancing, or reverse Austin osteotomy). Transfer metatarsalgia — excessive shortening of the 1st metatarsal shifts load to the 2nd and 3rd MT heads; occurs when osteotomy technique shortens the 1st MT by >3–4 mm. AVN of the metatarsal head — rare with distal osteotomies when the lateral soft tissue attachments are preserved; more common with extensive medial and lateral dissection that disrupts the nutrient artery. Stiffness — limited MTP ROM postoperatively; minimize by starting early gentle ROM exercises at 1–2 weeks.

08 Lesser Toe Deformities

Hammertoe, Claw Toe, Mallet Toe

Flexible vs. rigid: a flexible deformity is passively correctable; a rigid deformity is not. The distinction is the single most important factor in determining treatment:

Flexible deformity → conservative (taping, padding, toe splints, accommodative shoes with extra depth) or minimally invasive procedures (percutaneous flexor tenotomy, flexor-to-extensor transfer).

Rigid deformity → arthroplasty (resection of the proximal phalanx head) or arthrodesis (fusion) of the PIP joint; address any associated MTP instability concurrently.

Surgical options: PIP arthroplasty (resection of the proximal phalanx head, K-wire fixation × 4 weeks), PIP arthrodesis (fusion with K-wire, absorbable pin, or intramedullary implant), flexor-to-extensor transfer (Girdlestone-Taylor procedure for flexible claw toe), extensor tenotomy/lengthening, metatarsal shortening osteotomy (Weil) for associated metatarsalgia.

Morton Neuroma

Perineural fibrosis of the common digital nerve, most commonly in the 3rd intermetatarsal space (between 3rd and 4th MT heads). Patients report burning, tingling, numbness in the affected web space, worsened by tight shoes and walking. The Mulder click (compression of the forefoot while palpating the interspace produces a palpable and sometimes audible click) is pathognomonic. Ultrasound (hypoechoic mass >5 mm) and MRI confirm the diagnosis.

Treatment ladder: wider shoes, metatarsal pad, NSAIDs → corticosteroid injection (1 mL betamethasone + 1 mL lidocaine, dorsal approach between the MT heads, advance needle until it is palpable plantarly at the interspace) — provides temporary relief in ~50%; limit to 3 injections (risk of plantar fat pad atrophy and plantar plate damage) → alcohol sclerosing injections (4% dehydrated alcohol diluted with local anesthetic to a total volume of 1–2 mL, injected into the neuroma under ultrasound guidance, series of 3–7 injections at 1–2 week intervals — causes chemical neurolysis with ~60–70% sustained improvement) → surgical excision (dorsal longitudinal incision centered over the interspace, retract the deep transverse metatarsal ligament or transect it, identify the common digital nerve proximal to its bifurcation, transect at least 1–2 cm proximal to the neuroma, allow the proximal stump to retract into soft tissue away from weight-bearing; specimen should be sent for histology; recurrence/stump neuroma rate ~15–20%).

Predislocation Syndrome & Crossover Toe

Attenuation of the 2nd MTP plantar plate and collateral ligaments leads to progressive instability, dorsal subluxation, and eventually medial crossover of the 2nd toe over the hallux. The drawer test of the 2nd MTP (dorsally directed force on the proximal phalanx) demonstrates pathologic laxity. Early treatment: taping the toe in corrected position, stiff-soled shoe, metatarsal pad. Surgical: direct plantar plate repair (Weil osteotomy + plantar plate reattachment through a dorsal approach) has become the standard for established crossover toe.

09 Plantar Fasciitis & Heel Pain

Plantar fasciitis is the most common cause of inferior heel pain, accounting for approximately 80% of cases. It is a degenerative enthesopathy (not primarily inflammatory) of the plantar fascia at its origin on the medial calcaneal tuberosity.

Risk Factors & Pathophysiology

Obesity (BMI >30), prolonged standing occupations, running (especially increased mileage), pes planus, pes cavus, limited ankle dorsiflexion (equinus), and tight gastrocnemius-soleus complex. Histopathology shows collagen degeneration, fibroblast proliferation, and mucoid degeneration (fasciosis) rather than acute inflammation.

Clinical Features

Classic presentation: first-step pain — severe heel pain with the first steps in the morning that improves after several minutes of walking, then worsens with prolonged standing or activity. Pain is localized to the medial calcaneal tuberosity on palpation. The windlass test (passive dorsiflexion of the hallux reproduces pain at the plantar fascial origin) is the most specific clinical test. Imaging is not required for diagnosis but may exclude other causes: lateral weight-bearing XR may show a calcaneal spur (present in 50% but not causative), MRI shows thickened plantar fascia (>4 mm) with increased signal. Ultrasound shows thickened hypoechoic fascia.

Treatment Ladder

Differential Diagnosis of Heel Pain

Injection Techniques for Heel Pain

Plantar fascia corticosteroid injection — the medial approach is most common: the needle is inserted at the medial border of the heel at the point of maximum tenderness, directed laterally and slightly superiorly toward the plantar fascial origin. Use 40 mg triamcinolone acetonide (or equivalent) with 1–2 mL 1% lidocaine (or 0.5% bupivacaine for longer analgesia). Ultrasound guidance improves accuracy (needle tip visualized entering the thickened fascia at its calcaneal origin) and may improve outcomes while reducing risk of inadvertent fat pad injection.

Risks of repeated injection: plantar fascia rupture (reported in 2–10% of injected patients; presents as sudden pain relief followed by lateral column overload, loss of arch height, and lateral plantar pain); fat pad atrophy (particularly with multiple injections or injection superficial to the fascia rather than deep to it; leads to persistent heel pain from loss of shock absorption); skin depigmentation at the injection site.

Platelet-rich plasma (PRP) injection — autologous blood product concentrated in growth factors (PDGF, TGF-beta, VEGF); injected into the plantar fascia at the origin under ultrasound guidance. Mechanism: promotes tendon/fascial healing rather than suppressing inflammation. Studies show equivalent or superior long-term outcomes compared to corticosteroid injection without the risks of rupture and fat pad atrophy. Disadvantage: not covered by most insurance plans; requires centrifugation equipment and venipuncture at the time of treatment.

10 Flatfoot & Cavus Foot

Adult-Acquired Flatfoot Deformity (AAFD) / Posterior Tibial Tendon Dysfunction

Progressive degeneration of the posterior tibial tendon leads to loss of the medial longitudinal arch, hindfoot valgus, and forefoot abduction. Most common in women over 40. Risk factors: obesity, hypertension, diabetes, corticosteroid use, seronegative arthropathy.

Clinical tests: Too-many-toes sign — when viewing the patient from behind, more lateral toes are visible on the affected side due to forefoot abduction. Single-heel-rise test — patient stands on one leg and rises onto tiptoe; inability to rise or failure of the heel to invert indicates PTTD. Medial ankle pain along the PT tendon course.

Johnson-Stainsby Classification

Cavus Foot

An abnormally high medial longitudinal arch with hindfoot varus, plantarflexed 1st ray, and associated claw toes. Unlike flatfoot, which is usually acquired, cavus foot is frequently due to an underlying neurologic condition — an etiology should always be sought.

Neurologic causes: Charcot-Marie-Tooth disease (CMT, most common — accounts for ~50% of cavus feet), friedreich ataxia, spinal dysraphism, poliomyelitis, spinal cord tumor, cerebral palsy. All patients with new or progressive cavus foot should have a thorough neurologic exam and consider spinal MRI.

Coleman block test — patient stands with the lateral foot on a wooden block, allowing the 1st ray to plantarflex off the edge. If the hindfoot varus corrects (hindfoot moves to neutral or valgus), the deformity is forefoot-driven (flexible hindfoot) and can be addressed with a dorsiflexory 1st metatarsal osteotomy. If the hindfoot varus persists, it is a rigid hindfoot varus requiring calcaneal osteotomy (Dwyer lateralizing or closing wedge).

Surgical reconstruction: Typically multicomponent: dorsiflexory 1st MT osteotomy + calcaneal osteotomy (Dwyer) + peroneus longus-to-brevis transfer (eliminates the deforming force on the 1st ray) + plantar fascia release + claw toe correction (Jones procedure: EHL transfer to 1st MT neck + IPJ fusion). In severe/rigid cases: triple arthrodesis for global deformity correction.

11 Ankle & Rearfoot Conditions

Ankle Sprains

Lateral ankle sprains (inversion injuries) account for 85% of all ankle sprains and are the most common musculoskeletal injury in athletes. The ATFL is injured first (weakest ligament, taut in plantarflexion), followed by the CFL (taut in dorsiflexion), and rarely the PTFL (strongest, usually intact except in dislocations). Medial (deltoid) sprains account for <5% of ankle sprains and should raise suspicion for associated injuries: fibula fracture (Weber B or C), syndesmotic injury, or Maisonneuve fracture (proximal fibula). Syndesmotic (high ankle) sprain — injury to the anterior inferior tibiofibular ligament (AITFL), interosseous membrane, and/or posterior inferior tibiofibular ligament; caused by external rotation or dorsiflexion; presents with pain at the anterior ankle joint line above the mortise, positive squeeze test (compression of the fibula to the tibia at mid-calf reproduces distal pain), and positive external rotation stress test. Recovery is significantly longer than lateral sprains (6–12 weeks); unstable syndesmotic injuries with widening of the mortise require surgical fixation.

Ottawa ankle rules — radiographs indicated if: bone tenderness at the posterior edge or tip of either malleolus, bone tenderness at the navicular or 5th MT base, or inability to bear weight immediately and in the ED (4 steps). Sensitivity ~98% for fractures; reduces unnecessary XR by 30–40%.

Physical examination maneuvers — the anterior drawer test is performed with the patient seated, the knee flexed, and the ankle in slight plantarflexion; the examiner stabilizes the distal tibia with one hand and draws the calcaneus/talus anteriorly with the other. Increased anterior translation or a soft endpoint compared to the contralateral side indicates ATFL insufficiency. The talar tilt test (inversion stress test) assesses CFL integrity: with the ankle in neutral, the examiner inverts the calcaneus; >10° talar tilt or >5° more than the uninjured side is positive. Both tests are most reliable when performed 4–5 days after injury (once acute guarding subsides) or under anesthesia. Stress radiographs can document laxity objectively.

Chronic Ankle Instability (CAI)

Recurrent ankle sprains and/or persistent “giving way” after an index sprain, affecting ~20% of patients. May be mechanical (ligament laxity) or functional (proprioceptive deficit). Conservative treatment: supervised proprioceptive/neuromuscular rehabilitation program, ankle bracing. Surgical: Brostrom repair (direct ATFL repair + imbrication of the inferior extensor retinaculum — Gould modification) is the gold standard; anatomic reconstruction preserving subtalar motion. Augmentation with suture tape or allograft (Brostrom-InternalBrace) may be used for revision or large patients.

Peroneal Tendon Pathology

Peroneal subluxation — rupture of the superior peroneal retinaculum allows tendons to sublux over the lateral malleolus; felt/heard as a painful snap with eversion. Acute: immobilization may suffice. Chronic/recurrent: retinacular repair ± groove-deepening procedure. Peroneal tendon tears — peroneus brevis longitudinal split tears are most common (compressed between the longus and the fibula in the retromalleolar groove); presents as lateral ankle pain and weakness with eversion. Treatment: debridement and tubularization if <50% of tendon involved; tenodesis of brevis to longus if >50%.

Achilles Tendon Rupture

Typically occurs 2–6 cm proximal to the calcaneal insertion (watershed zone). Common in “weekend warriors” aged 30–50 with sudden eccentric loading. Thompson test: patient prone, feet hanging off table; squeeze the calf — absent plantarflexion = positive = rupture. A palpable gap may be present.

Treatment: Surgical repair (Krackow suture technique, early protected weight-bearing) vs. functional rehabilitation (serial casting with progressive dorsiflexion, then boot with heel wedge). Meta-analyses show similar outcomes with accelerated functional rehab protocols, but re-rupture rates are slightly higher non-operatively (~5% vs ~2%). Surgery preferred in young, active patients.

Tarsal Coalition

An abnormal connection (fibrous, cartilaginous, or osseous) between tarsal bones; affects ~1% of the population. The two most common types: calcaneonavicular (best seen on 45° oblique XR — “anteater sign”) and talocalcaneal (middle facet; best evaluated with CT — the “C sign” on lateral XR is suggestive). Presents in adolescence as rigid, painful flatfoot with limited subtalar motion and recurrent ankle sprains. Treatment: conservative (orthotic, activity modification) → surgical resection (for calcaneonavicular: bar resection with EDB muscle interposition; for talocalcaneal: resection if <50% of the posterior facet involved) → triple arthrodesis for extensive coalition with degenerative changes.

12 Diabetic Foot Assessment

Diabetic foot complications are the leading cause of non-traumatic lower-extremity amputation. Approximately 15–25% of diabetic patients will develop a foot ulcer during their lifetime, and the 5-year mortality after a major amputation exceeds 50%. Systematic foot assessment identifies risk and directs preventive strategies.

Comprehensive Diabetic Foot Exam

Neurologic assessment:

10-gram Semmes-Weinstein monofilament — the single most validated screening tool for loss of protective sensation (LOPS). Test 4 sites per foot minimum: hallux plantar surface, 1st MT head, 3rd MT head, 5th MT head. Inability to perceive the monofilament at ≥1 site = LOPS. 128 Hz tuning fork — tests vibration perception at the hallux DIP; loss correlates with large-fiber neuropathy. Ankle reflexes — absent Achilles reflex suggests sensorimotor neuropathy. Ipswich Touch Test — screening alternative: lightly touch the hallux, 3rd toe, and 5th toe bilaterally; inability to perceive ≥2 sites indicates neuropathy (no equipment needed).

Vascular assessment:

Pedal pulses — palpate dorsalis pedis and posterior tibial arteries. Ankle-brachial index (ABI): ankle systolic pressure / highest brachial pressure. Normal 1.0–1.3; <0.9 = peripheral arterial disease; >1.3 = non-compressible (calcified) arteries (common in diabetes — ABI unreliable). In diabetic patients with calcified arteries: toe-brachial index (TBI) >0.7 is normal (digital arteries rarely calcify); transcutaneous oxygen pressure (TcPO2) >40 mmHg indicates adequate perfusion for healing; skin perfusion pressure (SPP) >40 mmHg predicts healing.

Musculoskeletal assessment: Evaluate for structural deformities (Charcot, hammertoe, bunion, prominent MT heads) that create focal pressure areas. Limited joint mobility (especially limited ankle dorsiflexion from equinus or glycosylated tissue) increases plantar pressures. The Achilles tendon should be assessed (Silfverskiold test). The prayer sign (inability to fully approximate the palms when pressing hands together) indicates limited joint mobility from glycosylation of periarticular structures — a marker for elevated plantar pressures and ulceration risk.

Dermatologic assessment: Inspect all surfaces including between toes. Check for callus (precursor to ulceration), fissures, tinea, nail dystrophy, and erythema. Callus under MT heads should be debrided to reduce focal pressure. Pre-ulcerative signs include hemorrhage within callus (subkeratotic hematoma), skin discoloration, and localized warmth. Autonomic neuropathy produces anhidrosis (dry skin) increasing fissure risk, and distended dorsal foot veins from loss of sympathetic vascular tone.

Diabetic Peripheral Neuropathy Classification

Sensorimotor polyneuropathy — the most common form; symmetric, distal, length-dependent “stocking-glove” pattern; affects small fibers first (pain, temperature) then large fibers (vibration, proprioception); leads to loss of protective sensation. Autonomic neuropathy — affects sweating (anhidrosis), vascular tone (arteriovenous shunting producing a warm, dry foot with bounding pulses despite possible coexisting macrovascular disease), and skin integrity. Motor neuropathy — intrinsic muscle atrophy leads to imbalance between extrinsic flexors/extensors, producing claw toes, prominent metatarsal heads, and altered plantar pressure distribution. The triad of sensory loss + motor imbalance + autonomic dysfunction creates the perfect environment for ulceration.

IWGDF Risk Classification

13 Diabetic Foot Ulcers

Wagner Classification

University of Texas (UT) Classification

More granular than Wagner; uses a grid of grade (depth) and stage (complications):

Increasing stage (A → D) dramatically increases amputation risk. Stage D (infection + ischemia) carries the worst prognosis regardless of wound depth.

Wound Assessment

Depth — probe with sterile instrument. Probe-to-bone (PTB) test: a sterile metal probe reaches bone through the wound — positive predictive value for osteomyelitis is 89% in the infected diabetic foot (specificity improves in high-prevalence settings). Negative PTB does not rule out osteomyelitis. Wound dimensions should be measured (length × width × depth) at each visit. Wound bed — document tissue types present: granulation (red, beefy, healthy), slough (yellow, devitalized fibrinous tissue), eschar (black, necrotic), epithelial (pink, new skin advancing from edges). Periwound skin — assess for maceration (white, soggy from excess moisture), callus formation (reduces wound contraction), erythema/cellulitis, and undermining or tunneling (measure clock-face direction and depth).

Wound Care Products

Offloading

The cornerstone of DFU management. Total contact cast (TCC) is the gold standard for plantar forefoot and midfoot ulcers — reduces plantar pressure by 60–80% and ensures compliance (non-removable). The removable walker made irremovable (wrapped with one layer of cohesive bandage or fiberglass to prevent removal) has shown similar healing rates to TCC and is more practical for many clinicians. Patients will not comply with removable offloading devices — studies show they are worn only 28% of the time when removable.

Advanced Wound Therapies

When standard wound care and offloading fail to achieve healing within 4 weeks, advanced therapies should be considered:

14 Charcot Neuroarthropathy

A progressive destructive arthropathy affecting the bones and joints of the foot and ankle in patients with peripheral neuropathy, most commonly diabetic. The incidence in diabetic patients is approximately 0.1–0.9%. Pathophysiology involves unrecognized repetitive microtrauma in the insensate foot triggering an uncontrolled inflammatory cascade (RANKL upregulation, osteoclastic bone resorption) leading to fracture, dislocation, and structural collapse.

Clinical Presentation

Acute Charcot presents as a hot, swollen, erythematous foot in a patient with neuropathy. Skin temperature is typically 2–6°C warmer than the contralateral foot. Pain may be present but disproportionately mild for the degree of pathology (neuropathy). The differential diagnosis includes cellulitis/osteomyelitis (look for ulcer, wound, elevated WBC/ESR/CRP), DVT (unilateral swelling, Doppler evaluation), and acute gout (sudden onset, 1st MTP most common, serum urate). Charcot is a clinical diagnosis of exclusion in the neuropathic patient.

Eichenholtz Classification

Anatomic classification (Sanders & Frykberg): Type I (forefoot, 20%), Type II (tarsometatarsal/Lisfranc, 40% — most common), Type III (naviculocuneiform/Chopart, 30%), Type IV (ankle, 10%), Type V (calcaneus, rare). Midfoot involvement (Types II–III) is the hallmark, producing the classic rocker-bottom deformity with plantar bony prominence predisposing to ulceration.

Surgical Indications

Surgery is reserved for: (1) recurrent ulceration over bony prominence not manageable with bracing/orthotics — exostectomy (plantar bony prominence removal); (2) gross instability or deformity precluding brace fitting — reconstructive arthrodesis (midfoot beaming with intramedullary bolts, plates, or external fixation); (3) ankle Charcot with valgus collapse — tibiotalocalcaneal arthrodesis with retrograde intramedullary nail; (4) limb-threatening infection. Surgery should ideally be performed during the coalescence or consolidation stage (lower complication rates).

Differentiating Charcot from Infection

The clinical overlap between acute Charcot and osteomyelitis/cellulitis is a major diagnostic challenge, as both present with a warm, swollen, erythematous foot. Key distinguishing features:

When the diagnosis remains uncertain, particularly when an ulcer overlies a Charcot deformity, the conditions may coexist. Bone biopsy is the gold standard for confirming or excluding osteomyelitis in equivocal cases. Labeled white blood cell (WBC) scan combined with a bone marrow (sulfur colloid) scan can help differentiate infection from neuropathic bone changes: spatially incongruent uptake patterns suggest infection.

15 Diabetic Foot Infections

Diabetic foot infection (DFI) is the most common reason for diabetes-related hospitalization and the proximate cause of ~60% of lower-extremity amputations in diabetic patients. It is a clinical diagnosis: presence of purulent drainage, or ≥2 signs of inflammation (erythema, warmth, swelling, tenderness, induration) in a wound.

IDSA/IWGDF Severity Classification

Microbiology & Culture

Mild, acute infections are typically monomicrobial (gram-positive cocci: Staphylococcus aureus, Streptococcus). Chronic, deep, or previously treated infections are often polymicrobial (adding gram-negatives: Enterobacteriaceae, Pseudomonas; and anaerobes: Bacteroides, Peptostreptococcus). Always obtain deep tissue cultures (curettage of the wound base after debridement, or tissue biopsy) — NOT superficial swabs, which grow colonizing organisms. Culture before antibiotics if possible.

Empiric Antibiotics

Osteomyelitis

Present in 50–60% of severe DFI. Suspect when bone is visible or palpable via the wound (probe-to-bone test positive). MRI is the imaging modality of choice (sensitivity 90%, specificity 80%): shows bone marrow edema (T1 hypointense, T2/STIR hyperintense). Plain XR has low sensitivity early but may show cortical erosion, periosteal reaction, or sequestrum in established disease. Bone biopsy with culture is the gold standard for confirming osteomyelitis and identifying the organism for targeted therapy.

Treatment: Surgical resection of infected bone (partial or complete) + 2–4 weeks of targeted IV/oral antibiotics is generally preferred over prolonged (6-week) antibiotic therapy alone, as surgical excision shortens the treatment course and has higher cure rates. In non-surgical candidates: 6+ weeks of culture-directed antibiotics with serial ESR/CRP monitoring. The “antibiotic-only” approach may be considered when: the patient is a poor surgical candidate, the bone involved is biomechanically essential (e.g., calcaneus or talus where resection would require amputation), or the infection is limited and the patient declines surgery. Monitor response with serial ESR (should decrease by ≥25% every 2 weeks) and CRP (normalizes faster than ESR, typically within 2–4 weeks if treatment is effective). MRI is unreliable for monitoring short-term treatment response due to persistent marrow signal changes even after successful treatment; serial plain radiographs showing osseous reconstitution and absence of progressive destruction are more useful for long-term follow-up.

Amputation Levels

16 Foot & Ankle Fractures

Ankle Fractures — Weber Classification

5th Metatarsal Fractures

Lisfranc Injury

Disruption of the tarsometatarsal joint complex; ranges from subtle ligamentous sprain to frank fracture-dislocation. Mechanism: axial load on a plantarflexed foot (e.g., fall from height, motor vehicle, athletic injury). Often missed — up to 20% misdiagnosed initially. Weight-bearing AP XR: look for >2 mm diastasis between 1st and 2nd MT bases; loss of alignment of the medial border of 2nd MT with medial border of intermediate cuneiform. A “fleck sign” (avulsion fragment between bases) is pathognomonic. CT scan for subtle injuries. Treatment: non-displaced, stable injuries may be managed with NWB cast × 6–8 weeks; any displacement or instability on stress views → ORIF (bridge plating or screw fixation) or primary arthrodesis (increasingly favored, especially for purely ligamentous injuries).

Calcaneus Fractures

High-energy injuries (fall from height, MVC). 10% bilateral, 10% associated lumbar compression fracture. Bohler angle (normally 20–40°): decreased angle indicates posterior facet depression. Sanders classification (based on coronal CT through the widest part of the posterior facet):

Talus Fractures — Hawkins Classification

Hawkins sign — subchondral radiolucency in the talar dome seen on AP XR at 6–8 weeks post-injury; indicates intact blood supply (disuse osteoporosis requires viable bone). Absence of the Hawkins sign does NOT confirm AVN but should raise suspicion — MRI at 3 months is definitive.

Metatarsal Fractures (Non-5th MT)

Acute metatarsal shaft fractures (2nd–4th MT) — usually result from direct trauma or twisting injury. Most are stable because adjacent metatarsals splint the fractured bone. Non-displaced or minimally displaced fractures: hard-soled shoe or walking boot × 4–6 weeks; weight-bearing as tolerated. Displacement >3–4 mm in any plane or angulation >10° in the sagittal plane (dorsal/plantar): closed reduction and immobilization; ORIF with plate or K-wires if reduction cannot be maintained. Multiple metatarsal fractures or fracture-dislocations are unstable and often require surgical fixation.

1st metatarsal fractures deserve special attention because the 1st ray bears one-third of forefoot load. Displacement that creates shortening or dorsal angulation of the 1st MT will result in transfer metatarsalgia to the 2nd MT. A lower threshold for surgical fixation (plate and screws) applies to 1st MT fractures compared to lesser metatarsals.

Pilon Fractures (Tibial Plafond)

High-energy axial loading injuries of the distal tibial articular surface. The Ruedi-Allgower classification: Type I (non-displaced cleavage fracture of the articular surface), Type II (displaced articular fracture with minimal comminution), Type III (significant comminution with impaction of the articular surface). Management follows a staged protocol: (1) initial spanning external fixation to restore length and alignment, reduce fracture, and allow soft tissue recovery (7–14 days); (2) definitive ORIF with anatomic articular reduction, bone grafting of metaphyseal void, and medial or anterolateral plating when soft tissue conditions permit (wrinkle test positive). CT scan is essential for preoperative planning. High complication rate: wound dehiscence 10–15%, infection 5–10%, post-traumatic arthritis nearly universal in Type III.

17 Sports Injuries

Turf Toe

Sprain of the 1st MTP plantar plate/capsule complex from forced hyperextension (dorsiflexion) of the hallux, classically on artificial turf.

Sesamoid Pathology

Sesamoiditis — overuse inflammation of the sesamoid complex; pain localized to the plantar 1st MTP; treat with offloading (dancer pad, orthotic with sesamoid cutout), activity modification, NSAIDs. Sesamoid fracture — acute (transverse fracture line, irregular edges on XR) vs. bipartite sesamoid (smooth, rounded, corticated edges; present in 10–30% of population, usually bilateral — compare contralateral foot). Acute fracture: NWB boot × 6 weeks, then orthotic; refractory → partial sesamoidectomy (preserve at least one to prevent hallux valgus/varus drift). Sesamoid AVN — chronic pain, sclerosis/fragmentation on XR, increased signal on MRI; sesamoidectomy if non-responsive to conservative care.

Achilles Tendinopathy

Non-insertional (2–6 cm proximal to insertion, midportion): fusiform swelling, morning stiffness, pain with running. Histology: failed healing response (tendinosis) rather than inflammation. Insertional (at calcaneal attachment): associated with calcification, Haglund deformity, retrocalcaneal bursitis.

Treatment: First line for midportion: eccentric loading program (Alfredson protocol — 3 × 15 repetitions of eccentric heel drops, both straight-knee and bent-knee, twice daily for 12 weeks). Heavy slow resistance training is an alternative. Adjuncts: heel lift, NSAIDs (short-term), GTN patches (limited evidence). Second line: ESWT, PRP injection. Corticosteroid injection is contraindicated (rupture risk). Refractory: surgical debridement ± FHL transfer for tendon augmentation. For insertional tendinopathy: eccentric exercises with the heel below step level are avoided (may aggravate); Haglund resection + retrocalcaneal bursectomy + debridement of calcific insertional disease ± reattachment with suture anchors.

Plantar Plate Injuries

The plantar plate is a thick fibrocartilaginous structure on the plantar aspect of the MTP joint that is the primary restraint against dorsiflexion and hyperextension. Injury most commonly affects the 2nd MTP joint due to its length and mechanical disadvantage. Grading: Grade 0 (plantar plate attenuation without tear), Grade 1 (distal transverse tear <50%), Grade 2 (distal transverse tear >50%), Grade 3 (complete transverse tear with or without longitudinal extension), Grade 4 (extensive tear with button-hole deformity and medial/lateral deviation). MRI and ultrasound can identify plantar plate tears with high sensitivity when performed by experienced musculoskeletal radiologists.

Treatment: Grade 0–1: buddy taping of the affected toe in slight plantarflexion, stiff-soled shoe or rocker-bottom shoe, metatarsal pad to offload the MT head; 6–8 weeks of conservative care. Grade 2–4 or failed conservative management: surgical repair via dorsal approach (Weil metatarsal shortening osteotomy to access the plantar plate, followed by direct repair of the plantar plate to the base of the proximal phalanx using suture anchors). Post-operative: taping and stiff-soled shoe for 6–8 weeks; formal physical therapy starting at 4 weeks.

Stress Fractures

Overuse injuries from repetitive subthreshold loading. Most common sites in the foot: 2nd metatarsal (“march fracture”), 3rd metatarsal, navicular (high-risk — non-union prone), and calcaneus. The shin splints → stress fracture continuum: medial tibial stress syndrome (periostitis) → stress reaction (bone marrow edema on MRI, normal XR) → stress fracture (cortical fracture line). Risk factors: female athlete triad (energy deficiency, menstrual dysfunction, low BMD), rapid training increases, poor footwear, biomechanical issues. MT stress fractures: walking boot × 4–6 weeks. Navicular stress fractures: NWB cast × 6–8 weeks (high complication rate if inadequately immobilized); CT to confirm healing before return; surgical fixation (percutaneous screw) for displaced or non-healing fractures.

Posterior Ankle Impingement

Pain in the posterior ankle with forced plantarflexion (en pointe in ballet, kicking). Caused by an os trigonum (accessory ossicle posterior to the talus, present in ~7% of population) or a Stieda process (elongated lateral tubercle of the posterior talus). Impingement of the os trigonum, FHL tendon, or posterior capsule between the tibia and calcaneus. Diagnosis: posterior ankle tenderness, pain with passive plantarflexion; MRI confirms. Treatment: posterior ankle injection (diagnostic and therapeutic) → if refractory: arthroscopic or open excision of the os trigonum.

Anterior Ankle Impingement

Bony impingement — anterior tibial and talar osteophytes impinge with dorsiflexion; common in athletes (soccer players, “footballer’s ankle”) and post-traumatic arthritis. Pain at the end range of dorsiflexion; palpable anterior osteophyte. Lateral XR shows kissing osteophytes on the anterior tibial lip and talar neck. Treatment: conservative (heel lift, activity modification, steroid injection) → arthroscopic debridement and osteophyte resection for refractory cases; good results in the absence of generalized arthritis.

Soft tissue impingement — meniscoid lesion or synovial hypertrophy in the anterolateral gutter following an inversion ankle sprain; causes persistent anterolateral ankle pain despite adequate ligament healing. Positive Molloy-Bendall test (impingement sign: palpation of the anterolateral gutter with the ankle in plantarflexion, then dorsiflexion reproduces pain). MRI may show soft tissue thickening in the anterolateral gutter. Arthroscopic debridement is definitive treatment when conservative measures fail.

Osteochondral Lesions of the Talus (OLT)

Focal defects of the articular cartilage and underlying subchondral bone of the talar dome; present in up to 50% of acute ankle fractures and 6–7% of ankle sprains. The medial talar dome (posteriorly) is most commonly affected. Patients report deep ankle pain, intermittent swelling, catching, or locking. Berndt-Harty classification: Stage I (subchondral compression), Stage II (partially detached osteochondral fragment), Stage III (completely detached but non-displaced fragment), Stage IV (displaced fragment). MRI is the imaging modality of choice for staging. Treatment: Stages I–II typically respond to immobilization and protected weight-bearing × 6 weeks. Stage III–IV or symptomatic refractory lesions: arthroscopic debridement + bone marrow stimulation (microfracture) for lesions <15 mm; osteochondral autograft transfer (OATS) or particulated juvenile cartilage allograft for larger defects or failed microfracture.

18 Pediatric Foot Conditions

Clubfoot (Talipes Equinovarus)

Congenital deformity occurring in ~1:1000 live births (bilateral in 50%). Components: CAVE — Cavus (high arch), Adductus (forefoot medially deviated), Varus (hindfoot inverted), Equinus (ankle plantarflexed). The Pirani scoring system grades severity from 0 to 6 based on six clinical signs (3 midfoot + 3 hindfoot parameters, each scored 0, 0.5, or 1): higher score = more severe.

Ponseti method (gold standard — >95% success rate): sequential manipulation and serial long-leg casting, changed weekly × 5–7 casts. Correction order follows the mnemonic “CAVE” in reverse priority:

(1) Cavus correction first — supinate the forefoot on the hindfoot to align the forefoot with the hindfoot (this must be done before abducting the foot).

(2) Adductus and varus simultaneously — abduct the foot with counterpressure on the lateral talar head (NOT on the calcaneus, which would cause a rocker-bottom deformity); each cast progressively abducts the foot.

(3) Equinus last — corrected only after the foot is fully abducted to 60–70°; a percutaneous Achilles tenotomy is required in ~80% of cases (performed under local anesthesia in the clinic), followed by 3 weeks in the final cast with the foot in 60–70° abduction and 15° dorsiflexion.

Maintenance: foot abduction brace (Denis Browne bar or Dobbs bar) worn 23 hours/day × 3 months, then nighttime and nap time until age 4–5 years. Recurrence rate with compliant bracing: ~5%; without bracing: ~80%. Non-compliance with the brace protocol is the single most common cause of recurrence.

Tibialis anterior transfer — for recurrent dynamic supination deformity (foot supinates during swing phase due to overpull of the tibialis anterior without peroneal opposition): the tibialis anterior tendon is transferred laterally to the 3rd cuneiform or cuboid to balance the foot. Performed after age 2.5–3 years.

Metatarsus Adductus

Medial deviation of the forefoot relative to the hindfoot; the most common foot deformity at birth. Flexible (passively correctable past midline) — resolves spontaneously in 85–90% by age 1 year; may use gentle stretching exercises. Rigid (not passively correctable) — serial casting starting at age 6–8 weeks for 6–8 casts (similar to Ponseti). Surgical correction (multiple MT osteotomies or midfoot osteotomy) is rarely needed and reserved for severe, rigid deformity persisting beyond age 4.

Flexible Flatfoot in Children

Physiologic flatfoot is normal in children under age 6 (medial arch develops with maturation of the tarsal ossification centers and strengthening of the posterior tibial tendon). The arch appears when standing on tiptoe or when the hallux is dorsiflexed (Jack test). No treatment is needed for asymptomatic flexible flatfoot; studies show arch supports and special shoes do NOT accelerate arch development. Intervention warranted only if: pain, functional limitation, or abnormal shoe wear — orthotic with medial arch support; UCBL for moderate cases.

Osteochondroses

Sever disease (calcaneal apophysitis) — the most common cause of heel pain in children aged 8–14, and the most common pediatric overuse injury of the foot. Traction apophysitis at the Achilles insertion on the calcaneal growth plate. Bilateral in 60%. Pain with medial-lateral calcaneal squeeze (positive calcaneal squeeze test); pain worsened by running and jumping; pain at the posterior-inferior heel (NOT plantar — plantar fasciitis is rare in children). Radiographs are generally unnecessary unless red flags are present (night pain, fever, non-mechanical pain pattern); the appearance of sclerosis or fragmentation of the calcaneal apophysis is a normal developmental variant and NOT diagnostic of Sever disease. Treatment: activity modification (reduce running volume), heel cups or cushioned heel lifts (reduce traction on the apophysis), gastrocnemius-soleus stretching program, icing after activity, temporary use of a walking boot for severe cases; self-limiting with closure of the calcaneal apophysis (typically age 12–15 in girls, 13–16 in boys).

Kohler disease — AVN of the navicular; peak age 3–7 years, boys > girls. Midfoot pain, antalgic gait. XR shows sclerosis, fragmentation, flattening of the navicular. Treatment: short leg walking cast × 6–8 weeks; uniformly self-limiting with complete reconstitution of the navicular.

Freiberg disease (infraction) — AVN/osteochondrosis of the 2nd metatarsal head (less commonly 3rd). Peak age 13–18, girls > boys. Pain at the 2nd MTP joint, limited ROM. XR: flattening, sclerosis, fragmentation of the MT head. Treatment: stiff-soled shoe, MT pad, activity modification. Refractory: surgical debridement, dorsal closing wedge osteotomy (to redirect viable plantar cartilage into the weight-bearing surface), or joint replacement.

Polydactyly & Syndactyly

Polydactyly — extra digits; postaxial (lateral, 5th toe duplication) most common in the foot. Surgical excision typically at age 9–12 months if causing shoe fitting difficulty or if cosmetically unacceptable. Syndactyly — webbing between toes; rarely causes functional problems in the foot and typically does not require surgery unless involving the hallux or causing angular deformity.

Congenital Vertical Talus

Also known as “rocker-bottom foot”; a rigid flatfoot deformity present at birth caused by irreducible dorsal dislocation of the navicular on the talar head. The talus is vertically oriented with its head pointing plantarly, and the hindfoot is in equinus and valgus. Unlike flexible flatfoot, the deformity does NOT correct with plantarflexion. Lateral radiograph in maximum plantarflexion shows persistent talonavicular dislocation with the talar axis directed toward the plantar surface. Associated with neuromuscular conditions (myelomeningocele, arthrogryposis) and chromosomal abnormalities (trisomy 13, 18) in up to 50% of cases. Treatment: reverse Ponseti method (serial casting with initial plantarflexion and inversion to reduce the talonavicular joint, followed by percutaneous Achilles tenotomy and pinning of the talonavicular joint in reduced position); open reduction if casting fails.

Curly Toes & Overlapping Toes

Curly toes — flexion and varus deviation of the lesser toes (most commonly 3rd, 4th, 5th); caused by tightness of the FDL and FDB tendons; bilateral in 25–50%. Most cases resolve spontaneously by age 6; taping may help. Persistent symptomatic cases: flexor tenotomy (simple percutaneous release of the FDL at the DIP level). Congenital overriding 5th toe (digiti quinti varus) — 5th toe dorsiflexed and adducted, overlying the 4th toe; does not resolve spontaneously. Surgical correction: Butler arthroplasty (racket-handle incision with extensor tenotomy, capsulotomy, and skin plasty) or syndactylization to the 4th toe for simple cases.

Tarsal Coalition (Pediatric Presentation)

See Section 11. Presents in adolescence (10–16 years) as the coalition ossifies. Key presentation: rigid, painful flatfoot with peroneal spasm (protective spasm limiting inversion/supination). Limited subtalar motion on clinical exam. Evaluation: oblique foot XR (calcaneonavicular), CT (talocalcaneal, gold standard for bony coalition), MRI (fibrous or cartilaginous coalition).

19 Podiatric Surgical Principles

Regional Anesthesia for Foot & Ankle Surgery

Regional anesthesia provides excellent intraoperative anesthesia and prolonged postoperative analgesia, reducing opioid requirements.

Surgical Approaches

Dorsal — most common approach for metatarsal osteotomies, hammertoe correction, Lisfranc ORIF; between extensor tendons, protecting the neurovascular bundle. Medial — used for bunion correction (1st MTP), navicular procedures, medial column arthrodesis, posterior tibial tendon repair. Lateral — calcaneus ORIF (extensile lateral or sinus tarsi), peroneal tendon surgery, lateral ankle stabilization, 5th metatarsal fixation. Plantar — reserved for plantar fasciotomy, sesamoidectomy, plantar plate repair (increasingly done through dorsal approach), Morton neuroma excision (some prefer dorsal). Plantar incisions should avoid weight-bearing surfaces and be placed along non-weight-bearing margins when possible to reduce painful scar formation.

Tourniquet

An ankle tourniquet (pneumatic or Esmarch bandage at 250 mmHg) provides adequate hemostasis for forefoot and midfoot surgery. A thigh tourniquet (250–300 mmHg, or limb occlusion pressure + 100 mmHg) is used for rearfoot and ankle surgery. Maximum safe tourniquet time: 2 hours for a thigh tourniquet; reperfuse for 15–20 minutes before reinflation. Contraindications: severe PVD, DVT, sickle cell disease.

Fixation Principles

Screws — cortical (fully threaded, functions as a positioning device unless using lag technique with glide hole) and cancellous (partially threaded, provides lag compression across fracture). Lag screw technique: glide hole in near cortex, thread hole in far fragment → compression across fracture. Headless compression screws (Herbert-type): used in articular fractures (sesamoid, talar dome). Plates — neutralization (protects a lag screw), buttress (prevents shear), bridging (spans comminution), locking (angular stability, useful in osteoporotic bone). K-wires (Kirschner wires) — temporary fixation, hammertoe/claw toe correction; removed at 4–6 weeks; risk: pin tract infection (5–10%). Staples — memory compression staples for arthrodesis (e.g., 1st TMT). External fixation — used in Charcot reconstruction, severely comminuted calcaneus fractures, limb salvage with soft tissue compromise.

Bone Healing

Primary (direct) bone healing — occurs with anatomic reduction and rigid fixation (absolute stability, interfragmentary strain <2%); haversian remodeling without visible callus. Secondary (indirect) bone healing — occurs with relative stability (strain 2–10%); involves inflammation → soft callus → hard callus → remodeling; visible callus on XR. Most fracture healing is secondary. Time to union: forefoot osteotomies 4–6 weeks; midfoot/hindfoot arthrodesis 8–12 weeks; ankle arthrodesis 12–16 weeks.

Factors Affecting Bone Healing

Post-operative Protocols

Perioperative VTE Prophylaxis

Venous thromboembolism risk after foot and ankle surgery is lower than after hip/knee arthroplasty but must be considered, particularly with prolonged non-weight-bearing immobilization. Risk factors warranting chemoprophylaxis: NWB >4 weeks, history of VTE, active malignancy, BMI >40, combined oral contraceptive or hormone replacement use, inherited thrombophilia, age >60. For high-risk patients: low-molecular-weight heparin (enoxaparin 40 mg SC daily) or rivaroxaban 10 mg daily for the duration of immobilization. Mechanical prophylaxis (calf compression, ankle pumps, early mobilization when permitted) for all patients.

Postoperative Wound Complications

Surgical site infection (SSI) — occurs in 2–4% of clean elective foot surgery; higher in diabetic patients (up to 10%), smokers, and patients on immunosuppressants. Risk reduction: perioperative antibiotics (cefazolin 2 g IV within 60 minutes of incision), meticulous hemostasis, tension-free closure, avoidance of tourniquet time >2 hours, smoking cessation ≥4 weeks preoperatively. Wound dehiscence — more common in diabetic patients and those with vascular compromise; manage with local wound care and secondary closure or skin grafting if needed. Delayed union / non-union — risk factors: smoking (single greatest modifiable risk factor), diabetes, NSAID use during bone healing (controversial but often avoided in the early postoperative period), inadequate fixation, infection.

20 Soft Tissue Procedures

Tendon Repair Techniques

Krackow suture — a locking whipstitch pattern that provides superior pull-out strength; standard technique for Achilles tendon repair. Typically uses a strong non-absorbable suture (#2 FiberWire or equivalent). Two Krackow locking loops in each tendon stump, tied with the foot in slight (~20°) plantarflexion. Kessler suture (modified) — a core suture technique with grasping loops inside the tendon substance; commonly used for flexor and extensor tendon repairs in the foot. The Bunnell suture is a crisscrossing locking stitch used for tendon-to-bone attachment.

Tendon Transfer Principles

A tendon transfer substitutes the function of a paralyzed or ruptured tendon using a functioning expendable donor. Key principles: (1) the donor must have adequate strength (at least grade 4/5 — transfers lose one grade of strength); (2) the donor must have similar excursion to the recipient; (3) the transferred tendon should have a straight line of pull; (4) the donor should be synergistic with the intended function when possible.

FDL-to-posterior tibial transfer — the most common tendon transfer in podiatry, used in Stage II PTTD. The FDL tendon is detached from its distal insertion, rerouted, and anchored into the navicular (via bone tunnel or interference screw). The FDL is chosen because: (1) similar line of pull to the PT; (2) lies in close proximity behind the medial malleolus; (3) minimal functional deficit from harvest (FHL and intrinsic muscles compensate). Always combined with bony procedures (calcaneal osteotomy, etc.).

Jones procedure — transfer of the extensor hallucis longus (EHL) to the 1st metatarsal neck, combined with IPJ fusion of the hallux. Used for claw toe correction in cavus foot. Girdlestone-Taylor — transfer of the FDL from the plantar surface to the dorsal extensor hood of the lesser toe; corrects flexible claw toe deformity.

Wound Closure Techniques

Primary closure — standard for clean surgical wounds; suture selection: skin closure with non-absorbable monofilament (nylon 3-0 or 4-0, removed at 2–3 weeks for foot) or absorbable subcuticular (Monocryl 4-0). Deep closure with absorbable braided suture (Vicryl 3-0 or 4-0) for capsule, periosteum, and subcutaneous layers. Delayed primary closure — wound left open initially and closed at 3–5 days; used when contamination is a concern (open fractures, infected wounds after debridement). Secondary intention healing — wound left open to granulate and contract; used for infected wounds, partial nail avulsion sites after matrixectomy, and some DFU management. Skin grafts — split-thickness skin graft (STSG) for large wounds with healthy granulation bed; full-thickness skin graft for plantar coverage (more durable). Negative pressure wound therapy (NPWT) — applies subatmospheric pressure (−75 to −125 mmHg) via an occlusive dressing; promotes granulation tissue formation, reduces edema, removes exudate; commonly used as a bridge to definitive closure or grafting in complex wounds.

Ganglion Excision

Ganglion cysts in the foot most commonly arise from the dorsal midfoot joints (TMT, naviculocuneiform). They present as firm, non-tender, translucent masses that transilluminate with a penlight (distinguishing them from solid tumors). Ultrasound confirms the cystic nature (anechoic fluid-filled structure with posterior acoustic enhancement) and identifies the stalk to the originating joint. Treatment: aspiration with an 18-gauge needle + corticosteroid injection (0.5 mL triamcinolone 40 mg/mL; high recurrence ~50% because the stalk is not addressed); surgical excision with identification and removal of the stalk to its joint capsule origin (recurrence ~5–10%). Avoid dorsal digital nerve injury during dorsal foot ganglion excision. Recurrent ganglions after excision may require more aggressive capsular resection.

Plantar Fibroma Excision

Plantar fibromatosis (Ledderhose disease) produces firm nodules within the plantar fascia, analogous to Dupuytren in the hand. Conservative: orthotic with fascia accommodation, topical verapamil, corticosteroid injection (may reduce size temporarily). Surgical: wide local excision of the involved fascia (subtotal fasciectomy) to minimize recurrence (~60% recurrence with simple enucleation, ~10–25% with wide excision). Risk of painful plantar scar and arch destabilization.

Skin Plasty Techniques

Z-plasty — transposes two triangular flaps to lengthen a contracted scar or change its direction; each limb should be 60° (provides ~75% length gain). Used for contracted digital scars or web space contractures. V-Y advancement — a V-shaped flap advanced distally and closed as a Y; used for digital tip reconstruction and lengthening of contracted soft tissue. Both techniques are essential tools for addressing post-surgical or post-traumatic contractures in the foot.

21 Arthrodesis & Joint Replacement

First MTP Arthrodesis (Fusion)

The gold standard for end-stage hallux rigidus and salvage for failed hallux valgus surgery. Optimal fusion position: 10–15° dorsiflexion relative to the 1st metatarsal (allows toe-off without impingement), 10–15° valgus (matches normal alignment), slight pronation (to allow pulp of hallux to contact ground). Test position intraoperatively by placing the foot flat on a surface — the hallux should rest flat without excessive pressure. Fixation: dorsal plate + lag screw (most stable construct), or crossed screws (2 cannulated 4.0 mm screws). Union rate: 90–95%. Patients can walk normally but cannot wear high heels (>2 inches) due to loss of MTP dorsiflexion.

Ankle Arthrodesis

Tibiotalar arthrodesis — indications: end-stage ankle arthritis (post-traumatic most common), failed TAR, avascular necrosis, Charcot. Position: neutral dorsiflexion, 5° external rotation (matching contralateral limb), 0–5° hindfoot valgus, slight posterior translation of talus. Fixation: crossed lag screws (2–3 large-fragment cannulated screws), anterior plate, or arthroscopic technique (faster recovery, lower wound complication rate). Union rate: 85–95%. Adjacent joint arthritis (subtalar, midtarsal) develops in 40–60% of patients over 10–20 years.

Tibiotalocalcaneal (TTC) arthrodesis — simultaneous fusion of the tibiotalar and subtalar joints. Indications: combined ankle and subtalar arthritis, Charcot ankle, talar AVN with collapse, revision after failed tibiotalar fusion. Fixation: retrograde intramedullary nail (large diameter, locked). Significant loss of hindfoot motion; adjacent joint compensation limited.

Total Ankle Replacement (TAR)

Modern TAR uses a mobile-bearing or fixed-bearing three-component design (metallic tibial and talar components with an ultra-high-molecular-weight polyethylene [UHMWPE] insert). Current commonly used implants include STAR (mobile-bearing, most long-term data), INFINITY (fixed-bearing, anterior approach), INBONE II (fixed-bearing, intramedullary tibial fixation), Salto Talaris (fixed-bearing), and Zimmer Trabecular Metal (porous tantalum for enhanced bony ingrowth). Indications: end-stage ankle arthritis in patients >50 years, low-demand, adequate bone stock, normal alignment (correctable deformity), intact vascularity, BMI <30 preferred. Contraindications: active or recent infection, Charcot neuroarthropathy, significant talar AVN (>50%), severe malalignment (coronal >15°), peripheral neuropathy, high-demand/heavy labor, insulin-dependent diabetes (relative). TAR preserves ankle ROM (useful for patients who need to walk on uneven terrain, stairs) and reduces adjacent joint degeneration compared to arthrodesis. 10-year survivorship: 80–90%. Complications: wound healing (anterior approach — the anterior tibial tendon and superficial peroneal nerve are at risk), component subsidence (particularly talar component in osteoporotic bone), polyethylene wear, osteolysis, progressive periprosthetic lucency (radiolucent lines >2 mm or progressive are concerning for loosening), gutter impingement (bone formation in the medial or lateral gutters causing painful limitation of motion — may require arthroscopic debridement). Follow-up: weight-bearing radiographs at 6 weeks, 3 months, 6 months, 1 year, then annually; assess component alignment, subsidence, periprosthetic lucency, and gutter impingement.

Subtalar Arthrodesis

Indications: post-traumatic subtalar arthritis (commonly after calcaneus fracture), tarsal coalition (failed resection), posterior tibial tendon dysfunction (component of triple arthrodesis), inflammatory arthropathy. Fixation: 1–2 large cannulated screws from the posterior calcaneus into the talar body, or lateral plate. Position: 5° valgus. Union rate: 85–95%.

Surgical technique considerations: Joint surfaces are denuded of cartilage using a combination of osteotomes, curettes, and a sagittal saw or burr. Subchondral bone is fenestrated (“fish-scaling” or drilling multiple 2.0 mm holes) to expose bleeding bone and promote vascular ingrowth. Bone graft (autogenous iliac crest, calcaneal, or allograft) is packed into the joint for large defects or revision cases. The sinus tarsi approach (oblique incision from the tip of the fibula to the base of the 4th metatarsal) provides excellent visualization of the posterior facet with less wound complication risk than the extensile lateral approach. Arthroscopic subtalar arthrodesis is gaining popularity for straightforward cases (no significant deformity), offering faster recovery and lower wound complication rates.

Triple Arthrodesis

Fusion of three joints: subtalar (talocalcaneal), talonavicular, and calcaneocuboid. Indications: rigid flatfoot (PTTD Stage III), rigid cavovarus foot, severe tarsal coalition, neuromuscular deformity, rheumatoid hindfoot arthritis. Eliminates hindfoot inversion/eversion and forefoot abduction/adduction. Fixation: screws and/or staples at each joint. Position: neutral dorsiflexion, 5° hindfoot valgus, forefoot aligned. Powerful deformity correction but significant stiffness. Compensatory midfoot/ankle arthritis may develop over time.

22 Orthotic Therapy

Types of Orthotics

Custom orthotics — fabricated from a cast or 3D scan of the patient’s foot. They are prescribed based on individual biomechanical findings. Prefabricated (OTC) orthotics — mass-produced; available in standard sizes; adequate for mild biomechanical abnormalities and as first-line intervention. Evidence shows custom orthotics are superior to prefabricated for specific conditions (PTTD, severe pes planus) but prefabricated devices may be equivalent for plantar fasciitis.

Functional orthotics — designed to control abnormal motion (e.g., overpronation); constructed from semi-rigid to rigid materials (polypropylene, carbon fiber composite); shell extends from heel to just proximal to MT heads; prescribed for biomechanical disorders (plantar fasciitis, PTTD, hallux valgus prevention). Accommodative orthotics — designed to redistribute pressure and cushion the foot; constructed from soft materials (EVA, Plastazote, PPT foam, leather); full-length; prescribed for the diabetic/neuropathic foot, RA, and elderly patients with atrophic tissue.

Orthotic Prescription Elements

Specialized Bracing

UCBL (University of California Biomechanics Laboratory) orthotic — a deep-cupped, rigid heel control device that extends above the heel and up the medial and lateral walls of the foot; provides maximum rearfoot control. Indicated for pediatric flexible flatfoot, early PTTD (Stage I–IIA), and adult flexible flatfoot. Arizona brace — an ankle-foot orthosis (AFO) consisting of a custom leather gauntlet laced around the ankle and hindfoot; provides control of both the ankle and subtalar joint. Indicated for PTTD Stage II when an orthotic alone is insufficient, ankle instability, and early Charcot (after TCC). CROW boot (Charcot Restraint Orthotic Walker) — a total contact custom bivalved clamshell AFO; the definitive brace for Charcot in the consolidation phase (Stage II–III).

Diabetic Footwear — Medicare Requirements

Under the Therapeutic Shoe Bill, Medicare covers one pair of extra-depth shoes + 3 pairs of molded insoles (or 1 pair of custom-molded shoes if extra-depth shoes are inadequate) per calendar year for patients with diabetes + one of the following: history of partial/complete amputation, history of foot ulcer, callus that could lead to ulceration, peripheral neuropathy with callus formation, foot deformity, or poor circulation. A podiatrist or other qualifying prescriber must certify the need; the shoes must be fitted by a qualified individual (pedorthist, orthotist, podiatrist).

Casting and Scanning Techniques

Plaster casting — traditional gold standard for capturing the foot in its corrected (neutral subtalar) position. The Root technique positions the subtalar joint in neutral (talar head equally palpable medially and laterally) and locks the midtarsal joint by loading the 4th and 5th rays dorsally. The cast captures this corrected relationship for the orthotic lab. Foam box impression — semi-weight-bearing impression into phenolic foam; simpler and faster than plaster but less precise for capturing rearfoot position; adequate for accommodative devices. 3D scanning — optical or laser scanning of the foot; increasing adoption due to speed, digital storage, and compatibility with CAD/CAM fabrication; accuracy comparable to plaster casting when performed in the subtalar neutral position.

Condition-Specific Orthotic Prescriptions

23 Physical Therapy & Rehabilitation

Ankle Rehabilitation Protocol

Following ankle sprain or surgery, a progressive rehabilitation program reduces recurrence and chronic instability:

Phase 1 (Acute, 0–2 weeks): RICE (rest, ice, compression, elevation); gentle active ROM (ankle alphabet, towel pulls); isometric strengthening (submaximal); pain-free weight-bearing as tolerated. Phase 2 (Subacute, 2–6 weeks): Progressive ROM (full dorsiflexion goal — knee-to-wall test, ≥10 cm from wall); resistance band exercises (inversion, eversion, dorsiflexion, plantarflexion); early proprioception (single-leg stance on stable surface, progress to foam/wobble board). Phase 3 (Return to Activity, 6–12 weeks): Advanced proprioception (BAPS board, unstable surfaces); sport-specific agility (cutting, jumping, lateral movements); progressive return to running; functional testing (single-leg hop for distance, Y-balance test).

Eccentric Loading Protocols

Alfredson protocol (Achilles tendinopathy) — 3 sets of 15 repetitions of eccentric heel drops, performed both with the knee straight (targets gastrocnemius) and knee bent (targets soleus), twice daily (180 reps total/day) for 12 weeks. Starting position: bilateral heel raise on a step; then slowly lower the affected heel below the step level over 3–5 seconds (eccentric phase). Use the unaffected leg to return to starting position (avoid concentric loading of the affected side). Pain during the exercise is expected and acceptable; stop only if pain becomes disabling. Add weight (backpack) when exercises become pain-free. ~60–80% good/excellent outcomes in midportion tendinopathy. Heavy slow resistance (HSR) training is an alternative: 3 exercises (seated calf raise, standing calf raise, leg press calf raise), 3 sessions/week, 12 weeks; progressive loading from 15-RM to 6-RM; comparable outcomes to Alfredson with better patient satisfaction (fewer repetitions).

Intrinsic Foot Strengthening

Short foot exercise — patient contracts the intrinsic foot muscles to raise the medial longitudinal arch while keeping the toes flat on the ground (“foot doming”). Activates the abductor hallucis, flexor digitorum brevis, and quadratus plantae. Evidence supports short foot exercises for improving arch height, dynamic balance, and plantar fasciitis symptoms. Other intrinsic exercises: towel curls, marble pick-ups, toe yoga (independent great toe elevation while keeping lesser toes on ground and vice versa).

Toe spread and press exercises — actively spread the toes apart (abduction) and press them into the ground without curling; targets the interossei and lumbricals. Heel raise with toe extension — engage the windlass mechanism by maintaining toe extension while performing a heel raise; strengthens intrinsic muscles in a functional closed-chain position. A progressive intrinsic strengthening program (3–4 exercises, 3 sets of 10–15 repetitions, performed daily for 8–12 weeks) has demonstrated benefit for plantar fasciitis, early PTTD, and medial tibial stress syndrome. These exercises are best taught by a physical therapist and can be verified with EMG biofeedback in research settings.

Manual Therapy

Joint mobilization techniques: talocrural posterior glide (improves dorsiflexion — particularly after immobilization), subtalar distraction and glides, 1st MTP dorsal glide (for hallux rigidus). Soft tissue mobilization: deep tissue massage of the plantar fascia, cross-friction massage of the Achilles tendon, instrument-assisted soft tissue mobilization (IASTM/Graston technique) for chronic tendinopathy and fasciopathy.

Modalities

Extracorporeal shockwave therapy (ESWT) — radial or focused acoustic waves; Level I evidence for chronic plantar fasciitis (2000–3000 impulses, 3 sessions, weekly); Level II for Achilles tendinopathy. Mechanism: stimulates neovascularization and growth factor release. Therapeutic ultrasound — 1 MHz continuous mode for deep tissues (e.g., Achilles, plantar fascia); limited evidence for standalone efficacy; may enhance phonophoresis drug delivery. Low-level laser therapy (LLLT) — some evidence for plantar fasciitis and Achilles tendinopathy; mechanism: photobiomodulation enhancing cellular metabolism. Cryotherapy — ice massage for acute inflammation and post-exercise recovery.

Return-to-Sport Criteria

Objective functional testing should guide return-to-sport decisions rather than time alone. Key criteria include:

24 Classification Systems

Wagner Classification (Diabetic Foot Ulcers)

University of Texas (UT) Classification

Eichenholtz Classification (Charcot Neuroarthropathy)

Sanders Classification (Calcaneus Fractures)

Hawkins Classification (Talus Fractures)

Weber Classification (Ankle Fractures)

Johnson-Stainsby Classification (PTTD / AAFD)

25 Surgical Hardware Quick Reference

26 ABI & Vascular Assessment Interpretation

Ankle-Brachial Index (ABI)

Toe-Brachial Index (TBI)

Digital arteries are less susceptible to medial calcinosis than ankle vessels, making TBI more reliable than ABI in diabetic patients. Normal TBI: ≥0.7. Healing threshold: TBI ≥0.6 generally adequate for healing of minor wounds. TBI <0.25 indicates critical ischemia.

Transcutaneous Oxygen Pressure (TcPO2)

Skin Perfusion Pressure (SPP)

SPP ≥40 mmHg predicts healing in ~80% of wounds; SPP ≥30 mmHg is the minimum threshold for healing. SPP is independent of arterial calcification and can be measured at the specific wound site. SPP is measured using a laser Doppler sensor beneath a blood pressure cuff on the dorsum or plantar surface of the foot; as the cuff deflates, the pressure at which blood flow returns to the skin is recorded as the SPP value.

Vascular Assessment Decision Algorithm

Segmental Pressures & Waveforms

A pressure gradient >20 mmHg between adjacent segments (high thigh → above knee → below knee → ankle) indicates a hemodynamically significant stenosis at that level. Doppler waveform morphology: triphasic (normal) → biphasic (mild disease) → monophasic (significant disease, loss of reverse flow component). Duplex ultrasound with peak systolic velocity ratios localizes stenoses for surgical planning.

Performing the ABI

Equipment: handheld continuous-wave Doppler (5–10 MHz probe), sphygmomanometer with appropriately sized cuffs for the arm and ankle. Technique: patient rests supine for 10 minutes before measurement. Measure systolic pressure in both brachial arteries (use the higher value as the denominator). At the ankle, place the cuff just above the malleoli and measure systolic pressure in the dorsalis pedis and posterior tibial arteries separately (use the higher of the two as the numerator). Calculate ABI for each leg: ABI = highest ankle pressure / highest brachial pressure.

Common pitfalls: (1) Using too small a cuff (falsely elevates pressure); cuff bladder width should be ≥40% of limb circumference. (2) Not allowing the patient to rest before measurement (exercise elevates pressure). (3) Relying on ABI alone in diabetic patients with calcified arteries (false elevation). (4) Not checking both pedal arteries (the higher value is used because a single vessel may be occluded while the other is patent). (5) Performing the test in a cold environment (vasoconstriction lowers ankle pressure).

27 Common Medications

NSAIDs

Antibiotics for Diabetic Foot Infection

Antifungal Agents

Neuropathic Pain Agents

28 Abbreviations Master List