Club foot and developmental dysplasia of the hip

Overview

Club foot and developmental dysplasia of the hip (DDH) are the two most important congenital orthopaedic conditions. Both are picked up by newborn examination, both are treated best when started early, and both are typical MCQ topics.

Remember: always examine the hips of a baby with club foot and the spine for spina bifida, because these conditions travel together.

Club foot (congenital talipes equinovarus, CTEV)

Definition

A fixed, three-plane deformity of the foot present at birth:

Epidemiology

• About 1-2 per 1000 births in Apley (up to 6 per 1000 in some races, Bailey).
• Boys about twice as often as girls.
• Bilateral in a third to a half of cases.
• Family history common; multifactorial inheritance.

Types and causes

Pathological anatomy

• The talus is the key bone: its neck points downwards and medially.
• The navicular is displaced medially on the talar head (subluxed talonavicular joint).
• The calcaneum is in equinus and varus and rotated medially under the talus.
• Soft tissues on the posterior and medial side are short and thick (tendo Achillis, tibialis posterior, calcaneofibular ligament).
• Calf muscles are small; the calf and foot stay smaller even after treatment.

Clinical features

• Foot turned inwards so that the sole faces backwards and medially.
• Small, high heel that feels "empty" (the calcaneum is pulled up).
• Deep medial crease and a single deep posterior crease.
• Cannot be dorsiflexed and everted to touch the front of the leg (in a normal baby it can).
• Thin calf, short foot.
• Check: hips (DDH), spine (spina bifida), other joints (absent skin creases suggest arthrogryposis).

Assessment

• Diagnosis is clinical; antenatal ultrasound may pick it up.
• Pirani and Dimeglio scores grade severity and follow progress.
• X-rays are used mainly to check progress: the talocalcaneal (Kite) angle is reduced (bones more parallel than normal).

Treatment: the Ponseti method (first line)

Start within days to a few weeks of birth.

1. Serial manipulation and well-moulded above-knee plaster casts, changed weekly (usually 5-8 casts).
2. Order of correction:
   • Cavus first: supinate the forefoot to line it up with the hindfoot (elevate the first ray).
   • Adductus and varus next: abduct the foot around a thumb pressing on the talar head laterally (the fulcrum).
   • Equinus last.
3. Percutaneous Achilles (tendo Achillis) tenotomy under local anaesthetic is needed in about 80% to correct residual equinus, followed by a cast for about 3 weeks.
4. Foot abduction orthosis (boots on a bar, e.g. Denis Browne type) holding feet externally rotated and slightly dorsiflexed: full time for 3 months, then nights and naps up to about 4 years.
5. Relapse: repeat casting; tibialis anterior tendon transfer at about 2.5-4 years for dynamic supination.

Surgery

• For failed or resistant feet, ideally before walking age: posteromedial soft tissue release (Turco or Cincinnati incision), lengthening tendo Achillis and tibialis posterior, releasing tight capsules.
• Neglected or relapsed feet in older children: soft tissue release plus bony procedures (lateral column shortening, calcaneal osteotomy); Ilizarov frame for gradual correction; triple arthrodesis only after growth stops (around 10-12 years or older).

Developmental dysplasia of the hip (DDH)

Definition

A spectrum from a shallow (dysplastic) acetabulum, through an unstable (dislocatable) hip and subluxation, to a dislocated hip. It replaced the older term "congenital dislocation of the hip (CDH)" because the condition can develop and change after birth.

Epidemiology and risk factors

• Neonatal instability is common, but most unstable hips settle within weeks; true dislocation is about 1-2 per 1000 live births.
• Girls are affected several times more often (about 4-7 times, depending on the source).
• Left hip is affected more often; bilateral in about 1 in 5.

Risk factors (several are "packaging" problems):

• Female sex (maternal hormones such as relaxin cause ligament laxity).
• First-born (tight uterus).
• Breech presentation, especially with extended legs.
• Family history.
• Oligohydramnios.
• Other packaging deformities: torticollis, metatarsus adductus, club foot.
• Swaddling with hips and knees straight and legs together.

Pathology

• Femoral head dislocates posteriorly and superiorly.
• Acetabulum stays shallow and anteverted; a false acetabulum may form above it.
• Ossific nucleus of the femoral head appears late and stays small.
• Obstacles to reduction: inverted labrum (limbus), hypertrophied ligamentum teres, pulvinar (fat) in the socket, tight transverse acetabular ligament, iliopsoas tendon constricting the capsule (hourglass capsule), tight adductors.

Clinical tests in the newborn

Signs in the older infant and child

• Limited abduction in flexion (the most reliable sign after about 3 months).
• Galeazzi (Allis) sign: knees at different heights with hips and knees flexed (thigh shortening).
• Asymmetrical thigh and buttock creases.
• Shortened, externally rotated leg.
• Walking child: limp, toe-walking on the short side, Trendelenburg gait; bilateral cases give a waddling gait and increased lumbar lordosis.
• Bilateral dislocation is easy to miss because the signs are symmetrical.

Imaging

X-ray lines:

• Hilgenreiner line: horizontal line through both triradiate cartilages.
• Perkins line: vertical line from the outer edge of the acetabular roof, at right angles to Hilgenreiner line. A normal head (ossific nucleus) lies in the inner lower quadrant.
• Shenton line: smooth arc along the underside of the femoral neck and upper border of the obturator foramen; broken in subluxation or dislocation.
• Acetabular index: slope of the roof; should not exceed about 30° in infancy.

Screening

• All newborns are examined (Ortolani and Barlow) at birth and again at about 6 weeks.
• Selective ultrasound for babies with risk factors (breech, family history) or abnormal examination.

Management by age

Rules of splintage: the hip must be reduced before splinting, extreme abduction must be avoided, and the hip should be able to move.

Complications of untreated DDH

• Limp, leg-length difference, Trendelenburg gait.
• Early secondary osteoarthritis of the hip.
• Back pain from lumbar lordosis (bilateral).

Club foot vs DDH at a glance

Quick revision

• CTEV: cavus, adductus, varus, equinus; fixed; boys; check hips and spine.
• Ponseti: weekly above-knee casts, cavus first, equinus last, talar head fulcrum.
• Achilles tenotomy in about 80%; brace full time 3 months, then nights to about 4 years.
• Brace non-compliance causes most relapses; resistant feet need posteromedial release.
• DDH: girls, first-born, breech, family history, oligohydramnios; left hip.
• Ortolani reduces (clunk in); Barlow dislocates (out).
• Ultrasound under 4-6 months; X-ray (Hilgenreiner, Perkins, Shenton) after.
• Pavlik harness up to about 6 months; closed reduction and spica 6-18 months; open reduction and osteotomy later.
• Avoid extreme abduction: avascular necrosis of the femoral head.

Written by The House Job from standard orthopaedic references (Apley; Bailey & Love).

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