Congenital & Pediatric Orthopedics

Paediatric orthopaedics is not adult orthopaedics scaled down. A child's bone behaves differently, heals differently, deforms differently and corrects differently, and the reasons are structural rather than incidental.

Almost every difference follows from three properties of a growing skeleton, and holding those three converts a long list of eponymous conditions into a small set of consequences.

1. The Growing Skeleton Is Different

The physis is both the opportunity and the danger. Because a child grows, an imperfect reduction may remodel to normal. Because the physis can be injured or tethered, an insult produces progressive deformity that worsens with every year of remaining growth.

The rule that follows is used constantly. Angulation in the plane of joint movement, close to an active physis, in a young child, remodels well. Rotational malalignment does not remodel at any age.

2. Form Follows Function

The second organising idea concerns the joints rather than the bones.

A joint is moulded by its own use during development. The acetabulum deepens because a concentric femoral head presses into it. The foot achieves its shape because it is loaded in a particular position.

The consequence is that a joint held in the wrong position does not simply function badly; it forms badly, and the deformity becomes structural.

This is why paediatric orthopaedics is so preoccupied with time. The same abnormality treated at six weeks, six months and six years requires a harness, an operation and a reconstruction respectively, and the outcomes differ correspondingly.

3. Developmental Dysplasia of the Hip

The name changed from congenital dislocation because the condition is a spectrum and because it can develop after birth rather than always being present at it.

The spectrum runs from a shallow but located acetabulum, through a hip that can be dislocated, to one that is dislocated and finally to one that is irreducibly dislocated.

Risk factors are mechanical. Breech presentation, female sex, first-born status, oligohydramnios and a family history all reduce the space or the tone available for normal hip development. The left hip is affected most often, because it lies against the maternal spine in the usual fetal position.

Swaddling with the hips extended and adducted is an important and preventable cause, which matters in India and across South Asia where tight swaddling is traditional. Hip-healthy swaddling leaves the legs free to flex and abduct.

Examining the hip

Ortolani and Barlow tests work only in the first weeks. Ortolani relocates a dislocated hip with a palpable clunk, and Barlow dislocates a located but unstable one.

After about three months both become unreliable, because the soft tissues contract and the hip can no longer be moved in or out of the socket.

Limited abduction then becomes the most reliable sign, along with the Galeazzi sign of apparent femoral shortening with the hips and knees flexed, and asymmetric thigh creases, which are common in normal infants and unreliable alone.

Imaging and treatment

Ultrasound is the investigation before the femoral head ossifies, which occurs at around four to six months, and the Graf method measures the alpha angle of acetabular coverage. After ossification a plain radiograph is used, assessed with Hilgenreiner and Perkin lines, Shenton line and the acetabular index.

Treatment is by age. Under six months, a Pavlik harness holds the hips flexed and abducted, allowing the acetabulum to remodel around a reduced head. Excessive abduction must be avoided, because it compresses the femoral head against the acetabular margin and causes avascular necrosis.

Between six and eighteen months, closed reduction under anaesthesia with a hip spica is usual. Beyond that, open reduction with femoral or pelvic osteotomy is required.

Whether all infants should have ultrasound screening remains unsettled. A 2025 evidence review found that universal screening increased non-surgical intervention without a corresponding reduction in late-presenting dysplasia or in the need for surgery, so the balance against overtreatment is genuinely unclear.

4. Congenital Talipes Equinovarus

Clubfoot is a fixed structural deformity present at birth, and its components are remembered as CAVE.

The order matters, because Ponseti correction follows exactly that sequence. Cavus is corrected first by supinating the forefoot to align it with the hindfoot, then adductus and varus are corrected together by abducting the foot around the talar head, and equinus is corrected last.

Correcting equinus before the other components produces a rocker-bottom foot, because the midfoot breaks rather than the ankle dorsiflexing.

The Ponseti method is weekly manipulation and casting, typically around five casts, followed by percutaneous Achilles tenotomy in the majority of feet to complete the equinus correction, then a foot abduction brace.

Indian series report excellent results. A recent tertiary centre study of 550 feet achieved full correction in 94.7 percent, required tenotomy in 77.2 percent, needed a mean of 5.18 casts, and had residual deformity in 5.3 percent.

The single most important teaching point is that relapse is a bracing problem, not a casting problem. The correction achieved by casting is reliable; what fails is brace wear, which must continue full time for around three months and then at night until the age of four or five. Families who stop early are the families whose children relapse.

5. Perthes Disease

Perthes disease is idiopathic osteonecrosis of the femoral head in a growing child, typically between four and eight years and far commoner in boys.

Presentation is a painless or minimally painful limp, and the pain, when present, is often felt at the knee, because the obturator nerve supplies both the hip joint and the medial knee.

The disease passes through necrosis, fragmentation, reossification and remodelling over two to four years, and the femoral head is soft and deformable during the fragmentation phase.

The principle of treatment is containment, meaning keeping the femoral head seated deeply within the acetabulum so that the acetabulum acts as a mould while the head is plastic. This is achieved by maintaining abduction, with bracing or with femoral or pelvic osteotomy.

Prognosis worsens with older age at onset, because there is less remaining growth in which to remodel, and with greater involvement of the lateral pillar of the femoral head.

6. Slipped Capital Femoral Epiphysis

Here the epiphysis slips off the metaphysis through the physis, and the classical patient is an overweight adolescent around the time of the growth spurt.

Hypothyroidism, growth hormone deficiency and renal osteodystrophy are recognised endocrine associations, and they should be considered particularly in a child who is younger or thinner than expected.

The presentation is again hip or knee pain with a limp, and knee pain in an adolescent must prompt hip examination.

The most useful clinical sign is obligate external rotation on hip flexion, since the slipped head forces the limb to rotate outward as the hip is flexed.

Radiographically, Klein's line drawn along the superior femoral neck should intersect part of the epiphysis, and fails to do so in a slip, and a frog-leg lateral view is essential because early slips are missed on the anteroposterior film alone.

Treatment is in situ pinning, and reduction of the slip is avoided because it disrupts the retinacular vessels and precipitates avascular necrosis. Accepting the deformity and stabilising the physis is safer than correcting it.

7. The Limping Child

The differential is organised by age and by the presence of fever, and the one diagnosis that cannot be missed is septic arthritis.

Septic arthritis of the hip is a surgical emergency, because pus under pressure in a joint with an intracapsular blood supply destroys articular cartilage within days and can infarct the femoral head.

Transient synovitis is the common mimic, following a viral illness, with a child who is systemically well and can usually still bear weight.

The Kocher criteria separate them: inability to bear weight, fever above 38.5 degrees, erythrocyte sedimentation rate above 40, and white cell count above 12,000. The probability of septic arthritis rises steeply as more criteria are met, approaching certainty when all four are present.

Aspiration is the definitive investigation, and treatment is urgent surgical drainage with antibiotics.

8. Variants That Are Not Disease

A large proportion of paediatric orthopaedic referrals are normal variants, and recognising them prevents unnecessary intervention.

Genu varum is physiological up to about two years, after which the legs pass through a valgus phase peaking around three to four years and settle by about seven.

Blount disease is the pathological version of varus, occurring in overweight children with medial metaphyseal beaking of the proximal tibia, and unlike physiological bowing it progresses.

Rickets is the other cause of pathological bowing and must be excluded biochemically.

In-toeing has three causes distinguished by age. Metatarsus adductus presents in infancy, internal tibial torsion in the toddler, and increased femoral anteversion in the older child who characteristically sits in a W position.

All three usually resolve without treatment, and the historical use of braces and special shoes has been abandoned because they do not alter the natural history.

9. Scoliosis and Torticollis

Scoliosis is a lateral curvature of the spine with rotation, and the rotation is what makes it visible.

The Adams forward bend test detects the rib hump, because bending forward removes the compensatory posture and displays the vertebral rotation as an asymmetric prominence of the rib cage.

A postural curve disappears on forward bending; a structural curve does not, and that single distinction separates the child who needs observation from the one who needs a radiograph.

The Cobb angle measures the curve on a standing radiograph, drawn between the endplates of the most tilted vertebrae at each end.

Skeletal maturity determines what happens next, because a curve progresses while growth remains. The Risser sign grades ossification of the iliac apophysis from zero to five, and a low Risser grade in a child still growing predicts progression.

Adolescent idiopathic scoliosis is the commonest form, affects girls disproportionately at the pubertal growth spurt, and is painless. Pain, a left thoracic curve, or a rapidly progressive curve in a young child are all atypical and require magnetic resonance imaging, because they suggest an underlying spinal cord abnormality such as syringomyelia or a tethered cord.

Broadly, curves under about twenty degrees are observed, moderate curves in a growing child are braced to prevent progression rather than to correct, and large curves are treated surgically.

Congenital scoliosis is different in origin and behaviour, arising from vertebral malformation such as a hemivertebra, presenting earlier, and associated with cardiac and renal anomalies that must be sought because they share an embryological window.

Congenital muscular torticollis

The sternocleidomastoid is fibrotic and shortened, so the head tilts towards the affected side and the chin turns away from it.

A firm swelling within the muscle may be palpable in early infancy. Most cases respond to stretching physiotherapy, and the associated conditions to look for are plagiocephaly from positional moulding and developmental dysplasia of the hip, which shares the intrauterine crowding mechanism.

10. Neuromuscular and Genetic Conditions

Cerebral palsy produces orthopaedic problems through muscle imbalance rather than through primary bone disease. Spastic muscles overpower their antagonists, joints are held in abnormal positions, and the bone and joint deform accordingly, which is the same form-follows-function principle stated earlier.

Hip surveillance is essential in cerebral palsy, because progressive hip displacement is common, painless until late, and far easier to prevent than to reconstruct.

Osteogenesis imperfecta results from defective type I collagen, giving fragile bones, blue sclerae, dentinogenesis imperfecta and conductive hearing loss. Bisphosphonates reduce fracture rates. It is the most important differential for non-accidental injury in a child with multiple fractures.

Achondroplasia results from a gain-of-function mutation in FGFR3, is autosomal dominant with most cases arising de novo, and produces rhizomelic shortening with a trident hand.

The danger in infancy is foramen magnum stenosis, which can cause central apnoea and sudden death, while spinal stenosis is the problem of later life.

Limb anomalies worth recognising

Radial club hand is a longitudinal deficiency of the radius, with the wrist deviated radially and the thumb hypoplastic or absent, and it is the one limb anomaly that mandates systemic investigation.

The reason is that the radius forms during the same embryological window as the heart, the kidneys and the marrow, so associations include the VACTERL group, Holt-Oram syndrome with cardiac septal defects, Fanconi anaemia and thrombocytopenia with absent radius. Finding the hand should prompt echocardiography, renal imaging and a blood count.

Sprengel deformity is congenital failure of scapular descent, leaving a small high scapula that limits abduction, sometimes tethered to the cervical spine by an omovertebral bar.

Polydactyly and syndactyly are the commonest congenital hand anomalies, and the practical point is timing: separation of fused digits is undertaken early enough to prevent the growing bones deviating around one another.

11. Worked Examples

Example 1. A 5-month-old girl born breech has limited abduction of the left hip and apparent shortening of the left femur on the Galeazzi test. What imaging and treatment?

Developmental dysplasia of the hip. At five months the femoral head may not yet be ossified, so ultrasound is appropriate, with a radiograph if ossification has occurred. Ortolani and Barlow tests are unreliable at this age because the soft tissues have contracted, which is why limited abduction is the more useful sign. A Pavlik harness is used under six months, avoiding excessive abduction, which causes avascular necrosis.

Example 2. A newborn has bilateral clubfeet. The parents ask why the ankle deformity is corrected last.

Because correcting equinus first breaks the midfoot rather than dorsiflexing the ankle, producing a rocker-bottom deformity. The Ponseti sequence follows CAVE: cavus is corrected first by supinating the forefoot to align it with the hindfoot, then adductus and varus together by abducting the foot around the talar head, and equinus last, usually assisted by percutaneous Achilles tenotomy. Relapse afterwards is almost always a failure of brace wear rather than of casting.

Example 3. A 13-year-old obese boy has knee pain and a limp. Hip flexion produces obligate external rotation. What is the diagnosis and why is reduction avoided?

Slipped capital femoral epiphysis. Knee pain in an adolescent must prompt hip examination, because the obturator nerve refers hip pain to the medial knee. Obligate external rotation on flexion is the characteristic sign, and a frog-leg lateral radiograph is required since early slips are missed on the anteroposterior view. Treatment is in situ pinning; forceful reduction disrupts the retinacular blood supply and causes avascular necrosis.

Example 4. A 4-year-old cannot bear weight, has a temperature of 39 degrees, an erythrocyte sedimentation rate of 60 and a white cell count of 15,000. Diagnosis and management?

All four Kocher criteria are met, so septic arthritis of the hip is near certain. This is a surgical emergency, because pus under pressure destroys articular cartilage within days and can infarct the femoral head through its intracapsular vessels. Urgent aspiration confirms the diagnosis and surgical drainage with antibiotics follows. Transient synovitis would present in a systemically well child who can usually still bear weight.

Summary

The growing skeleton differs by three properties: a physis, a thick periosteum and remodelling capacity.

Angulation near an active physis remodels; rotation never does.

Form follows function, so a joint held wrongly forms wrongly, which is why timing dominates treatment.

Developmental dysplasia is a spectrum with mechanical risk factors, and tight swaddling with extended hips is a preventable cause.

Ortolani and Barlow work only in the first weeks; limited abduction is the later sign.

Ultrasound before ossification, radiograph after, and avoid excessive abduction in a Pavlik harness.

Clubfoot corrects in the CAVE order, and equinus last to avoid a rocker-bottom foot.

Ponseti relapse is a bracing failure, not a casting failure.

Perthes is treated by containment, using the acetabulum as a mould while the head is plastic.

Knee pain in a child can be hip disease, through the obturator nerve.

Slipped epiphysis is pinned in situ, because reduction causes avascular necrosis.

Four Kocher criteria make septic arthritis near certain, and the hip is a surgical emergency.

Bowing before two and knock knees at three are normal; Blount disease progresses.

Adams forward bending separates postural from structural scoliosis, and pain or a left thoracic curve requires magnetic resonance imaging.

Congenital muscular torticollis tilts the head towards the lesion and turns the chin away, and it accompanies hip dysplasia and plagiocephaly.

Radial club hand demands a heart, a kidney and a blood count, since the radius forms in the same window as all three.

Osteogenesis imperfecta is the key differential for non-accidental injury.

In achondroplasia the infant danger is foramen magnum stenosis.