History

See Table 6.1.

Table 6.1 Important features of a ‘locomotor’ or ‘musculoskeletal’ history

Examination

The examination of children with musculoskeletal problems is often opportunistic, as they may be in pain. Close observation that starts when the child and family walk into your consulting room is often the most useful examination technique.

Table 6.2 lists important features of the musculoskeletal examination. Remember the mnemonic GALS (gait, arms, legs, and spine).

Table 6.2 The musculoskeletal examination

The essence of the examination is engaging with the child and not losing their trust by hurting them. Perform a general examination, particularly noting any skin rashes. Watch the child walk (if the child is of walking age). Observe the bones and joints, look at and compare sides. Ask the child to move the joint (active movement), and then palpate and move joints for the child (passive). If it looks, feels and moves normally then it probably is normal.

Investigations

Try to subject children to investigations only where absolutely necessary. X-rays are important when looking for a bone or joint abnormality. A full blood count, blood culture and inflammatory markers (erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP)) will help you to distinguish a simple mechanical problem from an infective or inflammatory condition. Where juvenile arthritis or connective tissue disease is suspected, appropriate autoantibody tests are important. If an infective arthritis is suspected, the joint should be aspirated to culture the organism. This is usually done under general anaesthetic (unless you are caring for a very sensible and stoical adolescent, who may cope with local anaesthetic and Entonox). Technetium bone scans may show areas of acute inflammation or infection (a ‘hot spot’). MRI scanning is extremely valuable in diagnosing most musculoskeletal disorders.

Principles of management

Children want to get back to ‘normal’ activity as quickly as possible and it is important that you discuss this with them.

You should work towards recovery with appropriate therapy, including medication, physiotherapy, occupational therapy, orthotics and psychological support. The child and family need education and support about the condition, the impact on school and family life, and, very often, financial support (disability living allowance). Social services and voluntary organizations may be able to help (see also Chapter 3).

‘My baby’s feet aren’t right’

A baby in utero is in a very confined space towards the end of pregnancy, resting in a flexed ‘fetal’ position. This can result in several ‘packaging defects’, with the feet being affected most often. These foot postures are always mobile, can be passively corrected to a normal position, and will resolve spontaneously. They include talipes calcaneovalgus (foot turned upwards, dorsum lies next to shin, heels pointing outwards), and postural talipes equinovarus. In these conditions, the foot may be passively stretched into the appropriate position, without difficulty.

Talipes equinovarus (club foot) (Figure 6.1)

In true congenital talipes equinovarus the foot posture is rigid, and it is not possible to correct the position. It occurs in about 1:1000 live births, is twice as common in boys, and in about 50% is bilateral. It is increasingly treated successfully, without surgery, with weekly manipulations, serial full-leg plaster casting, and division of the achilles tendon. The correct position obtained at about 3 months is maintained with orthoses at night only; this is the Ponseti technique. Look out for associated spina bifida, neuromuscular abnormalites, chromosomal disorders and developmental dysplasia of the hip. The inheritance is multifactorial, with a recurrence risk of 1 in 50 if the infant is male and 1 in 20 if female.

Figure 6.1 Talipes equinovarus.

‘Funny toes’

It is common for one or two toes to be out of line with each other. Most commonly the third toe curls inwards and lies underneath the second toe. Sometimes the 2nd to 5th toes have a flexed posture (hammer toe). These deformities usually resolve by 18 months of age and parents may be reassured. If it is still present after that time, and causing problems, an orthopaedic surgeon should see the child. Toe syndactyly, particularly of the second and third toes, is common and requires no treatment.

Gait abnormalities

Bow legs (genu varum)

Normal infants are bow-legged when they start to walk. This results from bowing of the tibia, often associated with tibial torsion (twisting of the tibia inwards) such that when the upper tibia is forwards, the ankle joint is directed inwards. It usually resolves by 3 years. Rickets may be the cause (and is particularly common in dark-skinned races in the UK because of vitamin D deficiency) – look at the other bones, especially the ribs (thickening at the costochondral junction – ‘rickety rosary’) and take a wrist X-ray (widened, frayed metaphyses, osteopenia). Vitamin D deficiency is increasingly being recognized in the population at large. Frank signs of rickets, such as bow legs, are still unusual.

Knock knees (genu valgum)

A large proportion of children aged 2–7 years have knock knees (with knees together and ankles wide apart). The condition resolves with time, and parents require simple reassurance. Measuring the distance between the ankles is helpful. If the distance remains the same on an annual basis, the condition is improving because the bones are lengthening.

Pigeon toed (in-toeing)

There are three main causes of an in-toeing gait, which relate to the anatomical site of the abnormality (Figure 6.2):

Figure 6.2 Causes of in-toeing: (a) metatarsus adductus; (b) tibial torsion; (c) femoral neck anteversion.

Out-toeing

The infant or toddler may hold one or both legs in external rotation at the hip, such that the foot turns out. This normally resolves by 18 months. Examination reveals excessive external rotation of the hip on the affected side.

Toe-walking

This is common and normal if it starts early and involves both feet with normal balance and manoeuvrability. The child can walk with feet flat if asked to do so. A careful examination to exclude cerebral palsy is important (see Chapter 14, p. 197).

Flat feet (pes planus)

Foot posture varies with age. When children start to walk they do so on feet that appear flat, firstly because there is true flatness of the medial longitudinal arch, and secondly because a fat pad fills the arch. Eighty-five per cent of children develop a medial longitudinal arch by 8 years of age. At any stage the arch can be demonstrated by asking the child to stand on tip-toe. If the medial longitudinal arch does not form, this is abnormal, and may indicate a stiff forefoot with arthritis, or excess ligamentous laxity.

Flat feet are usually painless. Some do have discomfort, which is improved by wearing shoes with a good arch support (such as trainers), or putting arch supports in standard shoes. It is often associated with knock knees (genu valgum).

Transient synovitis of the hip

Case 6.1 describes the classical presentation of transient synovitis, which is the most common cause of acute hip pain in children. It occurs most often in boys (70%) in the 3–10-year age group and usually accompanies or follows a viral infection. Presentation is with acute-onset pain or limp. Pain may be referred to the thigh or knee. The child is not normally unwell, and is usually comfortable at rest. There may be a mild temperature and a decreased range of movement of the hip, particularly internal rotation.

The main differential diagnosis is septic arthritis of the hip. This causes rest pain, a decreased range of all movements, and the child is febrile and unwell. If in doubt do a full blood count, inflammatory markers, a blood culture and an X-ray. A septic joint will be more likely if there is a neutrophilia and markedly raised inflammatory markers. Ultrasound scan may demonstrate an effusion in either condition, and a joint aspiration under ultrasound guidance with appropriate analgesia should be performed if in any doubt. Transient synovitis is managed with rest and non-steroidal anti-inflammatory drugs (NSAIDs) and will improve, usually within a week, with no long-term problems.

Legg–Calvé–Perthes disease (Figure 6.3)

This condition was simultaneously described by all three clinicians, Legg, Calve and Perthes, in 1910, and is an idiopathic avascular necrosis of the capital femoral epiphysis. Typically it presents in boys aged 5–12 years with a limp or pain of gradual onset. It is bilateral in 10–15%. There may not be much to find initially, but later there is a loss of internal rotation, muscle wasting and limb shortening.

Figure 6.3 X-ray appearance of Legg–Calvé–Perthes disease.

X-rays may initially be normal and then show increased density in the femoral epiphysis, which becomes fragmented and irregular, and then gradually re-ossifies over a period of 18–36 months. There is little evidence that any interventions alter the natural history of the disease. The younger the child at disease onset, the better the outcome. The extent of the epiphyseal involvement and the sphericity of the femoral head and its congruency with the acetabulum at disease resolution predicts the development of early osteoarthritis. Long-term deformity, metaphyseal damage and degenerative osteoarthritis are complications. A large randomized control trial of bisphosphonate therapy in Perthes is currently underway, in an effort to improve the prognosis.

Slipped upper femoral epiphysis (Figure 6.4)

A 10- to 15-year-old boy who is overweight is most likely to present with pain and limp from a SUFE. Restricted abduction and internal rotation is found, and it is bilateral in 30%. The onset is usually insidious, although it may be acute following minor trauma. The diagnosis is made on an X-ray (ensure that lateral views are obtained), which shows a posterior and inferior slip of the epiphysis on the metaphysis through the growth plate. Management is surgical, and usually consists of a pin to prevent further slippage.

Figure 6.4 Slipped upper femoral epiphysis (SUFE).

Developmental dysplasia of the hip

Although a cause of limp, this condition should normally be detected after birth on routine neonatal examination (see Chapter 17, p. 248); however, late presentations with a limp do occur. DDH represents a spectrum of disorders ranging from hip dysplasia, through subluxation to frank dislocation. The prevalence of the condition is about 1.5:1000 and is commoner in girls. Screening examination, with Barlow’s and Ortolani’s tests (see Figure 6.5), should enable early diagnosis and treatment with normal subsequent joint development. If the screening examination is abnormal the baby should have an ultrasound scan, which will give a detailed assessment of both the hip and the acetabulum. If hip dysplasia is confirmed, treatment should be supervised by a paediatric orthopaedic surgeon and physiotherapist. The infant will be put in a splint (usually a Pavlik harness, fitted expertly by paediatric physiotherapists), which maintains about 60° abduction and 90° flexion of the hip, but allows kicking of the lower leg. This maintains the femoral head within the acetabulum and allows each to grow normally. It may be required for 8–12 weeks and must be carefully monitored for fit as the child grows.

Figure 6.5 Tests for developmental dysplasia of the hip (DDH): (a) Ortolani; (b) Barlow.

Routine ultrasound scanning is offered at birth and at 6 weeks to those babies with a family history of hip dysplasia who have a higher risk of DDH. Asymmetry of the skin folds of the groin and thigh, limitation of abduction on the affected side, and shortening of the affected leg are all later signs of hip dislocation, as is a limp or abnormal gait when the infant starts to walk. If it is detected at this late stage, or if early intervention has failed, hip abduction using traction and a plaster hip spica may be tried, but complex surgery is usually needed.

Acutely painful limb – trauma

Children are frequently brought to the A&E department with a painful limb with a history of trauma. By and large, ‘sprains’ do not happen in young children, and if the child cannot weight bear or is unable to use the arm, the likelihood is that there is a fracture, and an X-ray is mandatory. Always consider carefully how the injury was said to have occurred and whether this is consistent with the findings (see Chapter 5) as non-accidental injury is an important differential diagnosis.

Acutely painful limb – infection

‘My child has swollen, painful joints’

Children often present with joint pains, and the first consideration that arises, after acute infection has been excluded, is whether this is mechanical or inflammatory. Mechanical joint pains tend to occur towards the end of the day, or are made worse by activity; there is often a history of trauma.

In contrast, inflammatory polyarthritis is worse after a period of inactivity, and so is particularly bad in the morning. It may take some time for the joints to ‘loosen up’ in the morning (morning stiffness). On examination, finding erythema, heat, tenderness, a restricted range of movement, soft-tissue swelling or a joint effusion confirms inflammation. The causes of polyarthritis are shown in Table 6.3.

Table 6.3 Causes of polyarthritis

Reactive arthritis

The commonest arthritis in children in the UK is ‘reactive arthritis’, secondary to an infection: post-streptococcal, post-viral and post-enteric. Although considered separately, Henoch-Schönlein purpura and transient synovitis are also post-viral in nature. Post-enteric arthritis is typically associated with salmonella, shigella and yersinia infections. Enthesitis (inflammation of tendons and ligaments close to their bony insertions) is a common feature. These children usually (95%) have the HLA B27 haplotype.

Juvenile idiopathic arthritis

Arthritis present for more than 6 weeks in a child under 16 years is classified as juvenile idiopathic arthritis (JIA), having excluded other causes.

The prevalence is 1 in 1000 in the UK (similar to diabetes), with an incidence of 10:100 000 per year. JIA is an autoimmune disease in which genetic and environmental factors combine in the pathogenesis. If a biopsy is taken, hyperplasia and inflammation of the synovium is found, which gives rise to the clinical signs.

Examination

This must include all the systems, since the disease can involve any system and extra-articular features provide helpful clues to aetiology. Each joint should be assessed in turn, including the often forgotten temporomandibular joints, and spine. See Figure 6.6 for the signs of JIA in the hands.

Figure 6.6 The hands in juvenile idiopathic arthritis (JIA). Note swelling of metacarpalphalangeal and proximal interphalangeal joints.

‘I’m concerned about my daughter’s back’

Scoliosis is a lateral curvature of the spine that may be further subdivided into postural, which disappears on bending forward and is likely to resolve with time (the cause may be leg length discrepancy), and structural.

Structural scoliosis, where there is rotation of the vertebral bodies, can be identified when the child bends forwards – the curvature remains, and a rib hump develops. Most are idiopathic (85%) and are seen in adolescent girls (4:1 female to male), 30% of whom have a positive family history. Some are congenital (secondary to a defect in the spine such as a hemivertebra) and the remainder are secondary to other disorders such as cerebral palsy, muscular dystrophy, neurofibromatosis or Marfan’s syndrome.

Idiopathic scoliosis has a tendency to progress, and is monitored by serial X-rays. Treatment includes bracing to support the spine and/or major corrective surgery.

Chronic limb pain

If there is anything atypical about the history or examination, routine bloods and X-rays should be done in order to rule out a bone tumour (osteosarcoma and Ewing’s tumour), or leukaemia (see Chapter 7). Bone tumours are rare and usually present with pain and swelling or occasionally pathological fracture.

Children with hypermobility may complain of generalized pains. Signs might include thumbs that can hyperextend onto the forearm, elbows and knees that extend beyond −10°, and hands that can be placed flat on the floor with legs straight. This needs to be explained, and physiotherapists may help with joint protection exercises.

Chronic pain syndrome

This is characterized by non-specific aches and pains in otherwise healthy adolescents in the absence of signs of pathological cause. Symptoms overlap with chronic fatigue, and excessive tiredness is often a feature. These children frequently miss a great deal of school. Management is by acceptance of symptoms, reassurance of no serious underlying abnormality, addressing psychological needs and a graded exercise programme.

Osgood–Schlatter disease

This is an over-use syndrome commonly occurring in active teenagers around puberty. There is tenderness and swelling of the tibial tuberosity secondary to detachment of cartilage fragments (traction apophysitis). It is bilateral in 25–50%. Management consists of reducing activity and analgesia. Support splints may help.

Rheumatic fever

This is a form of reactive arthritis, and, although rare in the UK, is a major cause of heart failure in the developing world because of resultant mitral valve disease (see also Chapter 9, p. 98). It is a post-streptococcal disorder characterized by a migratory transient arthritis, a skin rash, carditis, subcutaneous nodules and occasionally chorea. Treatment of streptococcal throat infections with penicillin has dramatically reduced the incidence in the developed world. The major and minor criteria are shown in Table 6.5. To make a diagnosis, two major criteria, or one major and two minor criteria, are required with supporting evidence of preceding group A streptococcal infection.

Table 6.5 The Jones criteria for diagnosis of rheumatic fever

Treatment consists mainly of rest, eradication of persistent streptococcal infection and anti-inflammatory medication – usually high-dose aspirin. Complications such as heart failure, pericardial effusion and persisting infection can occur. Valvular damage, particularly to the mitral valve, may necessitate surgery.