The child with a limp

Limping and gait disorders in children are not uncommon, but how should we assess the child with altered gait, what are the red flags are and when should we seek help?

Limp is a fairly common symptom amongst children. Most are benign and self-limiting, but a few need urgent intervention. Many will present to the practice nurse in triage appointments, and a few may be mentioned in passing during child health reviews and immunisations.

A systematic approach to assessment, including thorough history-taking and focused examination will help the practice nurse rule out many causes of pain and assess which children need investigation and further management.

WHAT IS A LIMP?¹

A limp is considered to be a deviation away from the expected walking pattern for the child’s age, and altered gait. We think of a limp as an asymmetrical walk, but a limp may be due to a bilateral condition and may be symmetrical.

A limp may be due to any or all of:

• Pain arising from structures in the lower body (not just the leg), including bones, joint, or soft tissues (including the soles and toes) and be traumatic, infectious, inflammatory, or neoplastic. It may be due to acute injury or secondary to existing disease of structures in the leg, such as conditions that make the bones weak (e.g. rickets, cysts, tumours). Pain causing limp may also arise from the pelvis or abdomen – e.g. a child with an acute abdomen caused by appendicitis.
• Structural abnormalities of limbs or joints: these may be congenital (such as abnormalities of the hip joint), or acquired through disease process, or injury. Causes include limb length discrepancies, joint abnormalities, muscle contractures or shortened tendons and problems of the bones such as rickets.
• Neuromuscular problems: unsteady gait can be a result of muscle injury, inflammation or dystrophy, or a lesion in the central or peripheral nervous system. Examples include cerebral palsy, the late effects of polio and Duchenne muscular dystrophy.

WHEN DOES A LIMP MATTER?^1,2

By far the majority of new limps seen in the surgery are mild and are caused by minor injury. The history is clear, the resolution has begun and everyone is happy. However, often things are not initially clear-cut. Often the history is unclear, the child too young to describe what happened and the pain difficult to assess.

Limps can be unilateral and asymmetrical, or bilateral (and sometimes symmetrical), and are types of abnormal gait. Parents frequently bring children to be seen for other abnormalities of gait such as in-toeing, bow legs and flat feet.

All limps and concerns regarding gait need thorough assessment and a working diagnosis: any limp which has been present for more than a week (and which is not clearly getting better on its own) needs a definite diagnosis, with further investigation if uncertainty remains.

Normal gait¹

The normal gait pattern in adults and older children consists of 60% in the stance phase (from heel strike to toe off), and 40% in the swing phase (from toe off to the next heel strike).

Normal gait requires normal nerve, joint and muscle function, normal sensation, balance and proprioception, and the absence of significant pain or injury.

Small children and gait patterns

Little children’s legs can look odd when they are standing and walking, particularly if you’re not used to looking at them. Developmentally normal children begin to walk at around 12 to 14 months of age, but the mature adult type gait pattern is not reached until about three years.

• Toddlers have a wide-based gate with the feet planted far apart, high stepped and flat-footed with arms out for balance.
• They have an externally rotated lower leg, and they taking a greater number of shorter steps.
• Heel-first walking doesn’t begin till age 2, and an adult type gait appears only around 8 years of age.
• Bow-leggedness reaches a maximum at about 12 months and is usually resolved by 18 months.
• If the child is short (a height less than the 25th centile) or has marked bowing or asymmetric leg alignment then rickets needs to be considered
• Toe-walking and in-toeing are common in toddlers.
• Children between the ages of 3 and 8 years commonly walk with a ‘knock kneed’ gait.
• Flat feet are common when walking up to the age of 6, although normal feet are flexible and will form an arc when the child goes up on tiptoe.
• Most crooked toes resolve with weight-bearing.

If these variations persist beyond the expected age range, are progressive or asymmetric, or if there is pain and limitation then referral is needed.

TYPES OF ALTERED GAIT (OR LIMP)

Antalgic gait

This is a limp due to pain. The child tries to spare the affected side from weight-bearing as much as possible, minimising time spent on the painful limb.

Circumduction gait

This occurs when one leg swings outwards as it swings forwards. It may be caused by leg length discrepancy, with a restricted joint movement, or with one-sided spasticity such as cerebral palsy.

Spastic gait

This is stiff, with foot-dragging and turning in of the foot. It is often seen in neurological disease such as cerebral palsy.

Ataxic gait

This is uneven and unsteady, and is usually of neurological cause.

Trendelenberg’s gait

This is due to muscle weakness or hip joint problems. When weight-bearing on the affected side the pelvis drops downwards on the opposite side. This lead to a rather waddling, swinging limp. It is seen in hip conditions including slipped upper femoral epiphysis, developmental dysplasia of the hip, arthritis muscle disease and neurological conditions.

Toe-walking

This gait is common in normal children although it is occasionally seen in neurological conditions.

High-stepping gait

The entire leg is lifted at the hip is due to lower leg muscle weakness, caused by conditions such as spina bifida or polio.

‘Clumsy’ gait

This is not a true limp but describes a child with frequent falls. Dyspraxia is a term for children with delayed motor development who tend to be clumsy. It is a late-maturation problem that tends to be familial.

DIFFERENTIAL DIAGNOSIS

After injury, splinters, blisters, ingrowing toenails or tired muscles are the most common causes.

More serious problems include:

• Septic arthritis: A febrile unwell child with acute limp, not weight-bearing, or unable to move the joint (septic arthritis or osteomyelitis).
• Malignancy: Persistent bone pain, bone/soft-tissue swelling, and systemic upset (fever, weight loss, night sweats, lymphadenopathy, abdominal mass, or organomegaly). Causes include bone tumours and leukaemia.
• Non-accidental injury (NAI): If suspected, child protection management procedures should be followed.
• Inflammatory disorders: May present with fatigue, rash, myalgia, arthralgia, pain, fever, malaise, and multisystem involvement.

Some conditions are relatively age-specific in their presentation, with smaller and non-verbal children representing a particular challenge in diagnosis. (Table 1)

TAKING A HISTORY

This follows the principles of all history takings – questions about the presenting complaint followed by systemic questions including developmental, family and social history. You need to know:

History of the limp

• When did it start? Remember that unwitnessed trauma is common in young children, but don’t forget non accidental injury.
• Limping? Tripping? Falling? Problems getting up?
• Can the carer or child account for it? What do they think caused it?
• How did it start? (Suddenly or gradually? Did the child just wake up with it? Did it happen after activity like sport? Did it stop the child, at once or eventually, from doing the things that brought it on? [text] Rapid onset of persistent pain is suggestive of injury or infection.
• How does it affect the child? What can’t they do?
• Is it painful?
  • Describe the pain e.g. sharp, stabbing, burning (younger children will find this difficult)
  • What makes the pain worse e.g. movement, weight bearing, impact (jumping)
  • On a scale of 1-10, where 10 is the worst pain ever, how bad is it? Is it constantly that bad or does something make it that bad?
• Is it getting better worse or staying the same?
• Does it change during the day? (Inflammatory conditions are typically worst in the morning and after rest, muscular pain is typically worse in the evening and after exercise).
• Is the child otherwise well? Ask particularly about
  • Viral illness
  • Recent infectious disease
  • Rashes
  • Bites
  • Foreign travel (think of reactive arthritis, tuberculosis)
  • Night sweats
  • Weight loss
• Does anything help? Medication? Particular postures? Children with an irritable hip usually adopt a position of hip flexion, external rotation, and slight abduction.
• Is the pain unilateral or bilateral? Bilateral leg pain that occurs only at night and is not associated with any limp, pain or other symptoms during the day, may represent ‘growing pains’, a diagnosis of exclusion.
• Consider NAI

Background history

• Developmental history (consider developmental dysplasia of the hip [DDH], Perthe’s disease, sickle cell anaemia),
• Social history
• Family history (particularly of gait disorder)
• General health
  • Irritability, poor sleep, unwillingness to walk are suggestive of inflammatory conditions
  • Recent sore throat, chest infection and upper respiratory tract infection may precede symptoms of an irritable hip (characteristically following an interval of 10 to 14 days after the infectious episode)
  • Gastrointestinal upset (possibly following foreign travel) may predate reactive arthritis
  • Sexual history may be relevant in the older child/adolescent with a presentation suggestive of reactive arthritis.
• Medication
• Ethnicity: The risk of osteomalacia and rickets is higher in children of Asian families with poor sun exposure and dietary vitamin D deficiency (e.g. from chapati flour not fortified with vitamin D)
• Sickle cell disease is common in children of central African origin and may be present in children of Mediterranean and western Asian origin
• Rashes such as psoriasis may associate with psoriatic arthritis
• Prior history of red eye is typical of acute uveitis in HLA-B27-associated arthritis in children.

EXAMINATION

This should include inspection, palpation, range of motion as well as observation of the child’s walking:

• Ensure proper exposure of the child, legs visible and barefoot so that you may observe the feet and toes
• Have the child walk across the room and back. Try to focus on movement at each of the hip, knee and ankle joints. If you see something, try to classify among the types of abnormal gait
• Can the child run, stand on one foot, hop on one foot, walk on heels and toes, walk heel-to-toe, squat and get up again? (simple screening tests for motor skills)
• Look and palpate for tenderness, swelling, bruising, heat, signs of injury. Check arms and trunk too, for ‘matching’ injuries.
• Joints should be tested for pain, range of movement and stiffness
• General examination should include height, weight, temperature, and general appearance: look for anything unusual that might suggest congenital disorder
• Growth charts are useful; normal size for age makes chronic pathological conditions much less likely
• Full neurological evaluation
  • Test lower extremities for strength, sensation and deep tendon reflexes.

Box 1 lists the red flags to be aware of in history and examination. Box 2 details urgent causes of limp.

Investigations

The investigation of limp and gait abnormality depends on the differential diagnosis.

Blood tests are useful if infection, inflammation or tumour are suspected (FBC, ESR and CRP.) Other specific blood tests can identify conditions such as Lyme disease.

X-ray, ultrasound and bone scanning may help to identify fractures, osteomyelitis, and Calvé-Legg-Perthe’s disease.

CT scanning is effective for abdominal and pelvic pathology and joint pathology.

MRI is the study of choice for soft tissue pathology and for evaluation of bone tumours.

Other conditions which may cause limp

Stress fractures occur secondary to repetitive microtrauma, often seen in children who begin activity after sedentary periods or after beginning a new sporting activity. They can occur almost anywhere in the legs and will often not show on plain radiographs, but may be observed on bone scan or MRI.

Patellofemoral Pain Syndrome (chondromalacia patellae) is a very common form of repetitive microtrauma is seen in active adolescents. Pain results from improper tracking of the patella, often due to weakness of the medial thigh muscles. The child often describes pain worse with activity, particularly knee bends and stair climbing, that is improved with rest. Treatment is quadriceps muscle strength balancing.

Toddlers’ Fracture Because the bones of young children are less brittle, relatively minor traumas such as jumping or twisting can result in incomplete fractures. Typically Toddlers’ fractures involve the tibia or calcaneous.

Legg-Calvé Perthe’s Disease Avascular necrosis of the femoral epiphyses (growth plates) which occurs in young children mostly between the ages of 4 and 8 years and mostly in males. It presents with gradual onset of limp with mild activity-related pain in the hip or knee. It can occur after injury to the hip, and an identical avascular necrosis occurs in patients with sickle cell disease.

Slipped Capital Femoral Epiphysis is mainly seen in overweight adolescents, especially boys, just prior to the growth spurt. It usually causes pain in hip, thigh, or knee and is due to a fracture or slippage of the growth plate at the top of the hip bone. There is a Trendelenburg gait. Immediate referral to orthopedics is needed or permanent damage to the hip can result.

Summary

The practice nurse is well placed to assess limp in children. As with all areas of practice, familiarity with examining the normal will increase the ability to identify the abnormal.

REFERENCES

1. Assessment of gait disorders in children: BMJ best practice: July 2014

http://bestpractice.bmj.com/best-practice/monograph/709.html

2. Patient.co.uk. Gait abnormalities in children, 2014. http://www.patient.co.uk/doctor/gait-abnormalities-in-children

3. Ashford and St Peter’s Hospital Paediatric Accident and Emergency dept: Limping child guideline: Red Flags. http://www.asph.mobi/Guidelines_Paediatrics/Limping%20Child.pdf