Congenital Vertical Talus (CVT) — 15 Marks (MS Ortho)

Definition

Incidence & Associations

• Rare deformity; may be unilateral or bilateral
• 50% are associated with neuromuscular/syndromic conditions:
  • Myelomeningocele
  • Arthrogryposis multiplex congenita
  • Prune-belly syndrome
  • Spinal muscular atrophy
  • Neurofibromatosis
  • Trisomies (13, 18)
• The remaining ~50% are idiopathic (isolated)
• A less severe form, oblique talus, exists - in this variant the navicular reduces with plantar flexion (treated conservatively)

Pathoanatomy

• Talus becomes hourglass-shaped; its longitudinal axis approximates the tibial axis
• Only the posterior third of talar dome articulates with the tibia
• Calcaneus displaced posteriorly; rounded anterior plantar surface develops
• Callosities form under the anterior calcaneus and over the talar head medially
• Forefoot becomes severely abducted; heel does not touch ground
• Dorsal capsules, ligaments, and tendons become contracted
• Posterior tibial tendon and peroneal tendons may migrate anterior to the malleoli, acting as dorsiflexors rather than plantarflexors - this is a key secondary pathology

Clinical Features

1. Rocker-bottom foot (Persian slipper/convex sole) - pathognomonic
2. Prominent medial/plantar talar head - visible and palpable bulge
3. Fixed equinovalgus hindfoot - cannot be corrected passively
4. Abducted and dorsiflexed forefoot
5. Deep dorsolateral skin creases anterior and inferior to the lateral malleolus
6. Peg-leg gait - awkward gait with limited forefoot push-off (in ambulatory children)
7. RIGIDITY - the deformity is non-reducible (distinguishes from flexible flatfoot)

Radiographic Findings

Lateral Radiograph (Weight-bearing + Forced Plantar-flexion views)

• In CVT: navicular does NOT reduce; the talus-first metatarsal alignment is NOT restored by plantarflexing the forefoot
• In flexible pes planus / calcaneovalgus foot: alignment IS restored on forced plantar-flexion
• In children <3 years, the navicular is unossified - its position is inferred from the medial cuneiform and first metatarsal alignment

AP Radiograph

• Increased talocalcaneal angle (>40°)
• Talonavicular divergence

Differential Diagnosis

Note: In calcaneovalgus foot, the hindfoot is in calcaneus (dorsiflexed); in CVT, hindfoot is in equinus (plantar-flexed) - an important distinction.

Treatment

Conservative Phase (All Ages - Initial Treatment)

• Serial outpatient casting with the forefoot progressively plantarflexed (opposite direction to Ponseti for clubfoot)
• Achieves relaxation of dorsolateral structures
• Achieves partial or complete reduction of the talonavicular joint
• Typically 4-6 casts over several weeks

Surgical Treatment (Definitive)

Age-Based Surgical Protocol (for persistent/recurrent deformity):

Open Reduction Technique (Kumar, Cowell & Ramsey)

1. Lateral incision over sinus tarsi - release calcaneocuboid ligament; reflect extensor digitorum brevis
2. Medial incision over talar head - expose head of talus and navicular
3. Posterior incision medial to Achilles - Z-plasty lengthening of Achilles tendon; posterior capsulotomy if needed

• Dorsal talonavicular ligament
• Plantar calcaneonavicular (spring) ligament
• Anterior superficial deltoid ligament
• Talocalcaneal interosseous ligament (partial)
• Z-plasty lengthening of contracted tendons: anterior tibialis, EHL, EDL, peroneals

• K-wire from navicular into talar neck (or posterior to anterior) to maintain talonavicular reduction
• Confirm reduction with intraoperative AP and lateral radiographs

• Repair talonavicular ligament
• Anterior tibialis tendon transfer to plantar aspect of talonavicular joint capsule (preferred by many - prevents recurrence)
• Cast immobilization post-operatively

Single-Stage K-Wire Joystick Technique (Dobbs)

• Threaded K-wire placed axially through the vertical talus from posterior acting as a "joystick"
• Talus manipulated into reduced position
• Wire advanced across talonavicular and subtalar joints to hold correction
• Percutaneous Achilles tenotomy completes the procedure

Complications

• Recurrence - most common complication; requires repeat casting or surgery
• Avascular necrosis of the talar head
• Wound breakdown (extensive soft tissue dissection)
• Stiffness / residual deformity
• Pin tract infection

Key Points for Exam (MS Ortho)

1. CVT = irreducible dorsal dislocation of navicular on talus - this is the pathological definition
2. Distinguishing test = forced plantar-flexion lateral radiograph - navicular does NOT reduce in CVT
3. Talus is nearly vertical; calcaneus in equinus; forefoot dorsiflexed and abducted
4. 50% associated with neuromuscular conditions (myelomeningocele, arthrogryposis most important)
5. Treatment progression: Serial casting (Dobbs/reverse Ponseti) → Percutaneous K-wire + Achilles tenotomy → Age-based open surgery → Triple arthrodesis in adolescents
6. Navicular is unossified until age 3 - use first metatarsal/medial cuneiform as surrogate on X-ray
7. Distinguish from calcaneovalgus foot: CVT has equinus hindfoot; calcaneovalgus has calcaneus (dorsiflexed) hindfoot

Hallux Valgus — MS Ortho

Definition

• Lateral deviation of the great toe at the first metatarsophalangeal (MTP) joint
• Medial deviation (varus) of the first metatarsal (metatarsus primus varus)
• Pronation of the hallux on its longitudinal axis
• Medial prominence of the first metatarsal head (bunion - bone + bursa)
• Lateral subluxation of the sesamoid apparatus

Anatomy of the Deformity

Etiology

1. Genetic / familial - strongest association, especially in adolescents
2. Tight/narrow footwear - accelerates development; highest HV rates in shoe-wearing populations
3. Hypermobility of first ray - TMT1 joint laxity contributes (controversial)
4. Pronated flatfeet - altered foot mechanics
5. Abnormal insertion of posterior tibial tendon
6. Increased obliquity of first metatarso-medial cuneiform joint - predisposes to metatarsus primus varus
7. Rheumatoid arthritis - causes severe HV with MTP joint destruction

Clinical Features

• Pain over the medial eminence (bunion pain) - most common complaint
• Difficulty fitting shoes (narrow toe box)
• Second toe deformity/pain - often the primary complaint in advanced cases
• Metatarsalgia - pain under 2nd metatarsal head (first ray defunctioned)
• Plantar callosity beneath 2nd MTP joint
• Corn on medial aspect of 1st MTP or dorsum of 2nd toe

• Lateral deviation of hallux, medial prominence at 1st MTP
• Bunion - swelling (bone + bursa) over medial eminence
• Pronation of hallux (nail facing medially)
• Hammer/claw deformity of 2nd toe
• Reduced/painful range of motion at 1st MTP (if OA has developed)
• Palpable sesamoids in lateral position (normally plantar)
• Assess: arch height, lesser toes, plantar callosities, gastrocnemius contracture, TMT1 hypermobility

Radiographic Evaluation

Key Angles

Severity Classification (by HVA + IMA):

MTP Joint Congruency (critical for planning):

• Congruent joint - articular surfaces parallel; deformity is within the joint surfaces (DMAA elevated); correcting by moving the metatarsal head only would leave an incongruent joint - requires correction at the articular level
• Incongruent joint - subluxated; metatarsal head can be realigned with soft-tissue + osteotomy

Treatment

Non-operative (First line)

• Wide toe box shoes
• Bunion pads / toe spacers
• Night splints (do NOT correct deformity permanently)
• Activity modification
• Treat pain but cannot correct the structural deformity
• Operative correction for cosmetic reasons alone is NOT indicated (except in progressive adolescent deformity)

Surgical Treatment

• Persistent pain despite adequate non-operative management
• Progressive deformity
• Significant functional limitation
• NOT cosmesis alone (10% dissatisfaction rate with surgery)

1. Severity of deformity (HVA, IMA, DMAA)
2. MTP joint congruency
3. Presence of arthritis
4. Age and activity level
5. First TMT joint hypermobility
6. Adolescent vs adult

Surgical Options by Severity

A. Soft-tissue Procedures Alone

• Indications: Mild-to-moderate HV with congruent joint; IMA < 13°; HVA < 25°; age > 55 years
• Components:
  1. Medial eminence resection
  2. Adductor hallucis tenotomy (from fibular sesamoid)
  3. Lateral capsulotomy of 1st MTP
  4. Fibular sesamoidectomy (McBride) OR lateral FHB release (modified - avoids hallux varus)
  5. Medial capsular imbrication (capsulorrhaphy)
• Note: Original McBride included fibular sesamoidectomy - now considered too aggressive due to hallux varus risk

B. Distal Metatarsal Osteotomies

• Indications: Mild-to-moderate HV; HVA < 35-40°; IMA < 15°; age < 50 years preferred
• Technique: V-shaped (60°) osteotomy through the metatarsal head - capital fragment displaced laterally 3-5 mm
• Combined with medial eminence resection and medial capsulorrhaphy
• Fixation: K-wire or cortical screw
• Results: 85-95% good results
• Advantages: Through cancellous bone (stable, good healing), minimal shortening, inherent stability
• Modified extracapsular chevron is the current workhorse for mild-moderate deformity

• Medially-based closing wedge osteotomy at base of proximal phalanx
• Corrects hallux valgus interphalangeus (deformity distal to MTP joint)
• Corrects ~8° valgus per 2.5-3 mm of wedge removed
• Used as adjunct to other osteotomies; rarely indicated alone

C. Shaft Osteotomies

• Indications: Mild-to-moderate HV; IMA 11-18°; HVA 20-40°
• Technique: Z-shaped osteotomy along the shaft of 1st metatarsal; capital fragment displaced laterally
• Can also correct DMAA, lengthen/shorten metatarsal, plantarflex capital fragment
• Fixation: 2 cortical screws
• Complication: "Troughing" (metatarsal collapse into plantar fragment - prevented by not shortening the short arms excessively)

• Oblique shaft osteotomy; used for moderate-severe deformity

D. Proximal/Basal Metatarsal Osteotomies

E. First TMT Joint Arthrodesis (Lapidus Procedure)

• Indications:
  • Severe HV with IMA > 15°
  • Hypermobile/unstable TMT1 joint
  • Recurrent HV after previous osteotomy
  • Adolescent HV with open physis (relative)
• Technique: Arthrodesis of 1st metatarso-medial cuneiform joint + adductor release + medial capsulorrhaphy
• Corrects the deformity at its root (metatarsus primus varus)

F. First MTP Joint Procedures

• Resection of proximal 1/3 of proximal phalanx
• Indications: Elderly, low-demand patients; HVA < 25°; age > 55 years; arthritis of 1st MTP
• Disadvantages: Weakness of push-off (cock-up hallux), transfer metatarsalgia, shortening; high recurrence without fusion

• Gold standard for: Severe HV with MTP OA; rheumatoid HV; neuromuscular HV; recurrent/failed previous surgery; cerebral palsy HV
• Position: 10-15° valgus, 25-30° dorsiflexion (relative to floor)
• Best long-term outcomes and lowest recurrence rate
• Akin osteotomy may be added for hallux valgus interphalangeus

Age-Based Surgical Approach Summary

Complications

• Recurrence (most common, esp. with inadequate IMA correction or ligamentous laxity)
• Transfer metatarsalgia (pain shifts to 2nd/3rd MTP)
• Infection, wound dehiscence
• Nerve injury: dorsomedial cutaneous nerve (terminal branch)

• Hallux varus - overcorrection; due to overzealous lateral release or fibular sesamoidectomy
• Avascular necrosis of 1st metatarsal head (chevron/distal osteotomies - rare if periosteum respected)
• Dorsal malunion - first metatarsal elevated, causes transfer metatarsalgia
• Troughing (scarf osteotomy)
• Non-union (Lapidus - ~1%)
• Shortened first ray (Keller, metatarsal neck osteotomy)
• Cock-up hallux (Keller arthroplasty)
• Stiffness / reduced MTP range

Juvenile Hallux Valgus

• Family history very common
• IMA often the primary driver
• Surgical treatment more difficult and disappointing
• Open physis is a relative contraindication to osteotomy through the physis
• Lateral hemiepiphysiodesis (medial physis tethering) used for progressive deformity with adequate remaining growth
• Lapidus (if TMT1 hypermobile) preferred over proximal metatarsal osteotomy
• Recurrence rate is higher than in adults

Key Points for Exam

1. Three components of HV: lateral hallux deviation + medial 1st MT angulation + hallux pronation
2. HVA (normal < 15°) and IMA (normal < 9°) are the key angles on weight-bearing AP X-ray
3. Congruent vs incongruent joint determines whether distal osteotomy alone can correct, or whether articular surface correction (DMAA correction or MTP fusion) is needed
4. Chevron: mild-moderate, IMA < 15°, HVA < 40°, through cancellous bone, stable
5. Lapidus: hypermobile TMT1 + severe HV - corrects at root cause
6. MTP fusion: best for arthritic, rheumatoid, recurrent, neuromuscular HV - lowest recurrence
7. Sesamoid realignment is essential - failure to reduce sesamoids = recurrence
8. Hallux varus is the dreaded complication of overcorrection (especially with fibular sesamoidectomy)
9. Operative correction for cosmesis alone is NOT indicated (10% dissatisfaction rate)