Bow legs (genu varum)

The normal toddler has a broad base gait. Many children evolve leg alignment with initially a degree of bowing of the tibiae, causing the knees to be wide apart – best observed while the child is standing with the feet together (Fig. 26.1). A pathological cause of bow legs is rickets; check for the presence of other clinical features (see Ch. 11). Severe progressive and often unilateral bow legs is a feature of Blount disease (infantile tibia vara), an uncommon condition predominantly seen in Afro-Caribbean children. Radiographs are characteristic with beaking of the proximal medial tibial epiphysis.

Knock-knees (genu valgum)

The feet are wide apart when standing with the knees held together (Fig. 26.2). It is seen in many young children and usually resolves spontaneously.

Flat feet (pes planus)

Toddlers learning to walk usually have flat feet due to flatness of the medial longitudinal arch and the presence of a fat pad which disappears as the child gets older (Fig. 26.3). An arch can usually be demonstrated on standing on tiptoe or by passively extending the big toe. Marked flat feet is common in hypermobility. A fixed flat foot, often painful, presenting in older children, may indicate a congenital tarsal coalition and requires an orthopaedic opinion. Symptomatic flat feet are often helped with footwear advice and, occasionally, an arch support may be required.

Variants of normal

In-toeing and out-toeing

There are three main causes of in-toeing:

The clinical features are described in Box 26.1.

Out-toeing is uncommon but may occur in infants between 6 and 12 months of age.

When bilateral, it is often due to lateral rotation of the hips and resolves spontaneously.

In-toeing

Box 26.1

Clinical features of in-toeing in children

Metatarsus varus

• Occurs in infants

• Passively correctable

• Heel is held in the normal position

• No treatment required unless it persists beyond 5 years of age and is symptomatic

Medial tibial torsion

• Occurs in toddlers

• May be associated with bowing of the tibiae

• Self-corrects within about 5 years

Persistent anteversion of the femoral neck

• Presents in childhood

• Usually self-corrects by 8 years of age

• May be associated with hypermobility of the joints

• Children sit between their feet with the hips fully internally rotated (‘W’ sitting)

• Most do not require treatment but femoral osteotomy may be required for persistent anteversion.

Toe walking

Common in young children and may become persistent, usually from habit; can walk normally on request. Needs to be distinguished from mild cerebral palsy or tightness of the Achilles tendons or inflammatory arthritis in the foot or ankle. In older boys, Duchenne muscular dystrophy should be excluded.

Vertical talus

Talipes equinovarus needs to be differentiated from the rare congenital vertical talus, where the foot is stiff and rocker-bottom in shape. Many of these infants have other malformations. The diagnosis can be confirmed on X-ray. Surgery is usually required.

Talipes calcaneovalgus

The foot is dorsiflexed and everted (Fig. 26.7). It usually results from intrauterine moulding and self-corrects. Passive foot exercises are sometimes advised. There is an association with developmental dysplasia of the hip.

Talipes

Flat feet

In older children and adolescents, a rigid flat foot is pathological. It is suggested by absence of a normal arch on tip toeing. It may be due to an associated tendo-Achilles contracture (ankle), or tarsal coalition (see below) or inflammatory arthropathy (juvenile idiopathic arthritis, JIA).

Tarsal coalition

Results from lack of segmentation between one or more bones of the foot, and coalitions that were fibrous or cartilaginous become symptomatic as they begin to ossify. They become progressively more rigid and limit normal foot motion. They often become symptomatic during the pre-adolescent years. Radiographs may be normal if the bars have not yet ossified. Corrective surgery may be required.

Pes cavus

In pes cavus, there is a high arched foot. When it presents in older children, it is often associated with neuromuscular disorders, e.g. Friedreich ataxia and type I hereditary motor sensory neuropathy (peroneal muscular atrophy). Treatment is required if the foot becomes stiff or painful.

Developmental dysplasia of the hip (DDH)

This is a spectrum of disorders ranging from dysplasia to subluxation through to frank dislocation of the hip. Early detection is important as it usually responds to conservative treatment; late diagnosis is usually associated with hip dysplasia, which requires complex treatment often including surgery. Neonatal screening is performed as part of the routine examination of the newborn (see Fig. 9.15), checking if the hip can be dislocated posteriorly out of the acetabulum (Barlow manoeuvre) or can be relocated back into the acetabulum on abduction (Ortolani manoeuvre). These tests are repeated at routine surveillance at 8 weeks of age. Thereafter, presentation of the condition is usually with a limp or abnormal gait. It may be identified from asymmetry of skinfolds around the hip, limited abduction of the hip or shortening of the affected leg.

On neonatal screening, an abnormality of the hip is detected in about 6–10 per 1000 live births. Most will resolve spontaneously. The true birth prevalence of DDH is about 1.3 per 1000 live births. Clinical neonatal screening misses some cases. This may be because of inexperience of the examiner, but in some it is not possible to clinically detect dislocation at this stage, e.g. where there is only a mildly shallow acetabulum. To overcome these problems, some centres perform ultrasound screening on all newborn infants. It is highly specific in detecting DDH but is expensive and has a high rate of false positives, and is not recommended in the UK. It is performed in some centres in infants at increased risk (family history, of breech presentation).

If developmental dysplasia of the hip is suspected, a specialist orthopaedic opinion should be obtained. An ultrasound examination allows detailed assessment of the hip, quantifying the degree of dysplasia and whether there is subluxation or dislocation. If the initial ultrasound is abnormal, the infant may be placed in a splint or harness to keep the hip flexed and abducted for several months. Progress is monitored by ultrasound or X-ray. The splinting must be done expertly as necrosis of the femoral head is a potential complication.

In most instances, a satisfactory response is obtained. Surgery is required if conservative measures fail.

Scoliosis

Scoliosis is a lateral curvature in the frontal plane of the spine.

In structural scoliosis, there is rotation of the vertebral bodies which causes a prominence in the back from rib asymmetry. In most cases, the changes are mild, pain-free and primarily a cosmetic problem; however, in severe cases, the spinal curvature can lead to cardiorespiratory failure from distortion of the chest.

Causes of scoliosis are:

Examination should start with inspection of the child’s back while standing up straight. In mild scoliosis, there may be irregular skin creases and difference in shoulder height. The scoliosis can be identified on examining the child’s back when bent forward (Fig. 26.8). If the scoliosis disappears on forward bending, it is postural although leg lengths should be checked.

Mild scoliosis will resolve spontaneously, or progresses minimally. If more severe, the severity and progression of the curvature of the spine is determined by X-ray. Severe cases are managed in specialist spinal centres where the place of non-medical treatment such as bracing will be considered, with surgery indicated only if severe or there is coexisting pathology such as neuromuscular or respiratory disease.

Torticollis

The most common cause of torticollis (wry neck) in infants is a sternomastoid tumour (congenital muscular torticollis). They occur in the first few weeks of life and present with a mobile, non-tender nodule, which can be felt within the body of the sternocleidomastoid muscle. There may be restriction of head turning and tilting of the head. The condition usually resolves in 2–6 months. Passive stretching is advised, but its efficacy is unproven.

Torticollis presenting later in childhood may be due to muscular spasm or secondary to ENT infection, spinal tumour (such as osteoid osteoma), cervical spine arthritis or malformation or posterior fossa tumour.

Acute-onset limb pain

Limb pain of acute onset has a number of causes. Trauma is the most common, usually accidental from sports injuries or falls, but occasionally non-accidental. Osteomyelitis and bone tumours are uncommon, but need urgent treatment.

Osteomyelitis

In osteomyelitis, there is infection of the metaphysis of long bones. The most common sites are the distal femur and proximal tibia, but any bone may be affected (Fig. 26.10). It is usually due to haematogenous spread of the pathogen, but may arise by direct spread from an infected wound. The skin is swollen directly over the affected site. Where the joint capsule is inserted distal to the epiphyseal plate, as in the hip, osteomyelitis may spread to cause septic arthritis. Most infections are caused by Staphylococcus aureus, but other pathogens include Streptococcus and Haemophilus influenzae if not immunised. In sickle cell anaemia, there is an increased risk of staphylococcal and salmonella osteomyelitis. Infection may be from tuberculosis; although rare in the UK, it needs to be considered, especially in the immunodeficient child.

Osteomyelitis

Presentation

This is usually with a markedly painful, immobile limb (pseudoparesis) in a child with an acute febrile illness. Directly over the infected site there is swelling and exquisite tenderness, and it may be erythematous and warm. Moving the limb causes severe pain. There may be a sterile effusion of an adjacent joint. Presentation may be more insidious in infants, in whom swelling or reduced limb movement is the initial sign. Beyond infancy, presentation may be with back pain in a vertebral infection or with a limp or groin pain in infection of the pelvis. Occasionally, there are multiple foci (e.g. disseminated staphylococcal or H. influenzae infection).

Investigation

Blood cultures are usually positive and the white blood count and acute-phase reactants are raised. X-rays are initially normal, other than showing soft tissue swelling; it takes 7–10 days for subperiosteal new bone formation and localised bone rarefaction to become visible. Ultrasound may show periosteal elevation at presentation. MRI allows identification of infection in the bone (subperiosteal pus and purulent debris in the bone) and differentiation of bone from soft tissue infection. Radionuclide bone scan (Fig. 26.11) may be helpful if the site of infection is unclear. The X-ray changes of chronic osteomyelitis are shown in Figure 26.12.

Treatment

Prompt treatment with parenteral antibiotics is required for several weeks to prevent bone necrosis, chronic infection with a discharging sinus, limb deformity and amyloidosis. Antibiotics are given intravenously until there is clinical recovery and the acute-phase reactants have returned to normal, followed by oral therapy for several weeks. Aspiration or surgical decompression of the subperiosteal space may be performed if the presentation is atypical or in immuno-deficient children. Surgical drainage is performed if the condition does not respond rapidly to antibiotic therapy. The affected limb is initially rested in a splint and subsequently mobilised.

Summary

Osteomyelitis

• Presents with fever, a painful, immobile limb, swelling and extreme tenderness, especially on moving the limb

• Blood cultures are usually positive

• Parenteral antibiotics must be given immediately

• Surgical drainage if unresponsive to antibiotic therapy.

The painful knee

When assessing a painful knee, the hip must always be examined, as hip pain is often referred to the knee.

Back pain

Back pain is a symptom of concern in the very young and pre-adolescent ages as, in contrast to adults, a cause can often be identified. The younger the child, the more likely there will be significant pathology. Red Flag clinical features are listed in Box 26.2.

Mechanical causes – there may be muscle spasm or soft tissue pain from injury, often sport-related or from poor posture or abnormal loading (such as carrying heavy school bags on one shoulder).

Tumours: benign or malignant – The spine is a common site for osteoid osteoma. It may also be the site of primary tumours or metastases.

Vertebral osteomyelitis or discitis – there is localised tenderness; in infants there is reluctance to walk or bear weight or pain on spine flexion along with fever and systemic upset. While plain X-rays may show abnormalities suggesting the diagnosis, further imaging (MRI) is often required. Treatment is with intravenous antibiotics.

Spinal cord or nerve root entrapment – from tumour or prolapsed intervertebral disc – often associated with trauma or heavy lifting,

Scheuermann disease – an osteochondrosis of the vertebral body; may present with a fixed thoracic kyphosis with or without back pain. The diagnosis is usually made on X-ray. In many cases, the radiographic changes are a coincidental finding and the patient is asymptomatic.

Spondylolysis/spondylolisthesis – stress fracture of the pars interarticularis of the vertebra. Increased risk with certain sporting activities, e.g. bowling in cricket or gymnastics. If bilateral, can result in spondylolisthesis, forward slip of the vertebral body and potential cord or nerve root compression. There is pain on spine extension and localised tenderness. Change may be apparent on X-ray but often further imaging (CT scan) is required.

Complex regional pain syndrome (CRPS) – diagnosed when no physical cause is found; may be exacerbated by psychological stress.

Reactive arthritis

Reactive arthritis is the most common form of arthritis in childhood. It is characterised by transient joint swelling (usually <6 weeks) often of the ankles or knees. It usually follows (or rarely accompanies) evidence of extra-articular infection. The enteric bacteria (Salmonella, Shigella, Campylobacter and Yersinia) are often the cause in children, but viral infections, sexually transmitted infections in adolescents (chlamydia, gonococcus), Mycoplasma and Borrelia burgdorferi (Lyme disease) are other causes. Rheumatic fever and post-streptococcal reactive arthritis are rare in developed countries but are frequent in many developing countries.

Fever is low grade. Acute-phase reactants are normal or mildly elevated and X-rays are normal. No treatment or only NSAIDs are required and complete recovery can be anticipated.

Septic arthritis

This is a serious infection of the joint space, as it can lead to bone destruction. It is most common in children <2 years old. It usually results from haematogenous spread, but may also occur following a puncture wound or infected skin lesions, e.g. chickenpox. In young children, it may result from spread from adjacent osteomyelitis into joints where the capsule inserts below the epiphyseal growth plate. Usually only one joint is affected, with the hip being a particular concern in infants and young children. Beyond the neonatal period, the most common organism is Staphylococcus aureus, and usually only one joint is affected. H. influenzae was an important cause in young children prior to Hib immunisation and often affected multiple sites. Underlying and predisposing illnesses such as immunodeficiency and sickle cell disease should be considered.

Presentation

This is usually with an erythematous, warm, acutely tender joint, with a reduced range of movement, in an acutely unwell, febrile child. Infants often hold the limb still (pseudoparesis, pseudoparalysis) and cry if it is moved. A joint effusion may be detectable in peripheral joints. In osteomyelitis, although a sympathetic joint effusion may be present, the tenderness is over the bone, but in up to 15% there is coexistent septic arthritis. The diagnosis of septic arthritis of the hip can be particularly difficult in toddlers, as the joint is well covered by subcutaneous fat (Fig. 26.15). Initial presentation may be with a limp or pain referred to the knee.

Juvenile idiopathic arthritis (JIA)

This is the commonest chronic inflammatory joint disease in children and adolescents in the UK. It is defined as persistent joint swelling (of >6 weeks duration) presenting before 16 years of age in the absence of infection or any other defined cause. Ninety-five per cent of children have a disease that is clinically and immunogenetically distinct from rheumatoid arthritis in adults. It has a prevalence of approximately 1 in 1000 children, (i.e. similar to epilepsy), with over 12 000 affected children in the UK.

There are at least seven different subtypes of JIA. Its classification is clinical and based on the number of joints affected in the first 6 months, as polyarthritis (more than four joints) (Fig. 26.16) and oligoarthritis (up to and including four joints) or systemic (with fever and rash). Psoriatic arthritis and enthesitis are further subtypes. Subtyping is further classified according to the presence of rheumatoid factor and HLA B27 tissue type. The subtypes and their clinical features are shown in Table 26.4.

Features in the history are gelling (stiffness after periods of rest, such as long car rides), morning joint stiffness and pain. In the young child, it may present with intermittent limp or deterioration in behaviour or mood or avoidance of previously enjoyed activities, rather than complaining of pain.

Initially, there may be only minimal evidence of joint swelling, but subsequently there may be swelling of the joint due to fluid within it, inflammation and, in chronic arthritis, proliferation (thickening) of the synovium and swelling of the periarticular soft tissues.

Long term, with uncontrolled disease activity, there may be bone expansion from overgrowth, which in the knee may cause leg lengthening or valgus deformity, in the hands, discrepancy in digit length, and in the wrist, advancement of bone age.

If systemic features are present, sepsis and malignancy must always be considered.

Complications

Chronic anterior uveitis

This is common but asymptomatic and can lead to severe visual impairment. Regular ophthalmological screening using a slit lamp is indicated, especially for children with oligoarticular disease.

Flexion contractures of the joints

These occur when the joint is held in the most comfortable position, thereby minimising intra-articular pressure. Chronic untreated disease can lead to joint destruction and the need for joint replacement.

Growth failure

This may be generalised from anorexia, chronic disease and systemic corticosteroid therapy (Fig. 26.17). May also be localised overgrowth such as leg length discrepancy due to prolonged active knee synovitis and undergrowth, such as micrognathia, usually seen in long-standing or suboptimally treated arthritis due to premature fusion of epiphyses.

Constitutional problems

Anaemia of chronic disease, delayed puberty.

Osteoporosis

Multifactorial aetiology, including diet, reduced weight bearing, systemic corticosteroids and delayed menarche. Reduce risk by dietary supplements of calcium and vitamin D; regular weight-bearing exercise; and minimise oral corticosteroids use and sometimes bisphosphonates.

Amyloidosis

Very rare now, causes proteinuria and subsequent renal failure and has a high mortality.

Prognosis

Long-term outcome studies have shown that at least one in three children will have ongoing active disease into adult years, with significant morbidity from previous inflammation, such as joint damage requiring joint replacement surgery, visual impairment from uveitis, or fractures from osteoporosis. There is also significant psychosocial morbidity. However, with current management approaches it is anticipated that long-term outcomes will improve.

Transitional care programmes are increasingly provided to facilitate the changes through adolescence and young adulthood and to help young people learn how to manage their chronic disease independently.

Case History

26.1 Systemic-onset juvenile idiopathic arthritis

A 2-year-old boy presented with a high fever (Fig. 26.18a) and malaise. A salmon-coloured rash was present at times of fever (Fig. 26.18b). Investigation showed markedly raised acute-phase reactants. Shortly afterwards, he developed severe polyarthritic joint disease. A diagnosis of systemic-onset juvenile idiopathic arthritis was made on the basis of the clinical presentation and exclusion of other disorders (Table 26.3).

He was treated with high-dose intravenous corticosteroids with rapid improvement, started on oral corticosteroids and weekly methotrexate given by subcutaneous injection. His mother was taught by the nurse specialist how to give the injections to him at home and a daily exercise programme to improve his mobility was provided. A year later he remained on weekly methotrexate. He had persistent problems with his hips, with joint damage on X-ray and may ultimately require hip replacements in his adult years. He is shorter than his peers. He is now at university studying economics and drives his own car.

Henoch–Schönlein purpura

This is the most common vasculitis of childhood and presents with a purpuric rash over the lower legs and buttocks, usually associated with arthritis of the ankles or knees. Other features are abdominal pain, haematuria and proteinuria (see Ch. 18).

Systemic lupus erythematosus

Systemic lupus erythematosus is rare in children, but may present in adolescent females typically with malaise, arthralgia and malar rash (often photosensitive). Organ involvement (kidneys, lung or CNS) are serious complications.

Juvenile dermatomyositis

Juvenile dermatomyositis (JDMS) is rare. It usually begins insidiously with malaise, progressive weakness (often difficulty climbing stairs) and facial rash with erythema over the bridge of the nose and malar areas and a violaceous (heliotropic) discoloration of the eyelids (see Fig. 27.10). The skin over the metacarpal and proximal interphalangeal joints may be hypertrophic and pink, and the nailfold capillaries may be dilated and tortuous. Muscle pain is a common, if non-specific, symptom and arthritis is present in 30%. Respiratory failure and aspiration pneumonia may be life-threatening. The condition is described further in Chapter 27.

Achondroplasia

Inheritance is autosomal dominant, but about 50% are new mutations. Clinical features are short stature from marked shortening of the limbs, a large head, frontal bossing and depression of the nasal bridge (see Fig. 11.10). The hands are short and broad. A marked lumbar lordosis develops. Hydrocephalus sometimes occurs.

Thanatophoric dysplasia

This results in stillbirth. The infants have a large head, extremely short limbs and a small chest. The appearance of the bones on X-ray is characteristic. The importance of the correct diagnosis of this disorder is that, in contrast to achondroplasia, its inheritance is sporadic. It may be identified on antenatal ultrasound.

Cleidocranial dysostosis

In this autosomal dominant disorder, there is absence of part or all of the clavicles and delay in closure of the anterior fontanelle and of ossification of the skull. The child is often able to bring the shoulders together in front of the chest to touch each other as a ‘party trick’. Short stature is usually present. Intelligence is normal.

Arthrogryposis

This is a heterogeneous group of congenital disorders in which there is stiffness and contracture of joints. The cause is usually unknown, but there may be an association with oligohydramnios, widespread congenital anomalies or chromosomal disorders. It is usually sporadic. Marked flexion contractures of the knees, elbows and wrists, dislocation of the hips and other joints, talipes equinovarus and scoliosis are common, but the disorder may be localised to the upper or lower limbs. The skin is thin, subcutaneous tissue is reduced and there is marked muscle atrophy around the affected joints. Intelligence is usually unaffected. Management is with physiotherapy and correction of deformities, where possible, by splints, plaster casts or surgery. Walking is impaired in the more severe forms of the disorder.

Osteogenesis imperfecta (brittle bone disease)

This is a group of disorders of collagen metabolism causing bone fragility, with bowing and frequent fractures.

In the most common form (type I), which is autosomal dominant, there are fractures during childhood (Fig. 26.19a) and a blue appearance to the sclerae (Fig. 26.19b) and some develop hearing loss. Treatment with bisphosphonates reduces fracture rates. The prognosis is variable. Fractures require splinting to minimise joint deformity.

There is a severe, lethal form (type II) with multiple fractures already present before birth (Fig. 26.20). Many affected infants are stillborn. Inheritance is variable but mostly autosomal dominant or due to new mutations. In other types, scleral discoloration may be minimal.

Osteogenesis imperfecta

 Osteogenesis imperfecta is often considered in the evaluation of unexplained fractures in suspected child abuse.

Osteopetrosis (marble bone disease)

In this rare disorder, the bones are dense but brittle. The severe autosomal recessive disorder presents with failure to thrive, recurrent infection, hypocalcaemia, anaemia and thrombocytopenia. Prognosis is poor, but bone marrow transplantation can be curative. A less severe autosomal dominant form may present during childhood with fractures.

Marfan syndrome

This is an autosomal dominant disorder of connective tissue associated with tall stature, long thin digits (arachnodactyly), hyperextensible joints, a high arched palate, dislocation (usually upwards) of the lenses of the eyes and severe myopia. The body proportions are altered, with long, thin limbs resulting in a greater distance between the pubis and soles (lower segment) than from the crown to the pubis (upper segment). The arm span, measured from the extended fingers, is greater than the height. There may be chest deformity and scoliosis. The major problems are cardiovascular, due to degeneration of the media of vessel walls resulting in a dilated, incompetent aortic root with valvular incompetence and mitral valve prolapse and regurgitation. Aneurysms of the aorta may dissect or rupture. Monitoring by echocardiography is required.