Limp and hip pain

Aim

To guide staff with the assessment and management of limp and hip pain.

Background

Limping may be due to pain referred from elsewhere:

• pain from the hip may refer to the thigh or knee
• pain from the spine or genitalia may refer to the hip
• always consider the possibility of non-accidental injury (NAI)
• limping for less than 3 days without any red flags does not require investigation.

Assessment

History

Ask about:

• trauma
• fever
• preceding infections
• rate of onset
• duration of limp / pain
• rashes
• drug exposure
• features of systemic disease with joint involvement
• morning stiffness.

Examination

General

• Temperature
• Inspect for rashes/bruises
• Assess for signs of the 'unwell child':
  • poor perfusion
  • tachycardia/tachypnoea.

Gait

• Fully mature gait is attained by the age of 4 years
• Running accentuates any pathological features of gait
• Recognised gait patterns include:
  • antalgic gait due to a pain in the lower limb
  • trendelenburg gait due to weakened hip abductors or an unstable hip fulcrum e.g. Perthes disease, slipped upper femoral epiphysis (SUFE)
  • spastic gait as seen in cerebral palsy
  • proximal muscle weakness gait seen in neuromuscular conditions.

Standing

• Examine the back and spine for tenderness or deformity (discitis may cause exaggerated lordosis)
• Look for pelvic tilt.

Supine

• Examine each joint separately for tenderness, swelling, effusion, erythema, warmth and range of movement
• Disorders of the hip usually cause restriction of hip abduction and internal rotation and pain on these movements
• Severe restriction of movement suggests septic arthritis
• Note the position held by the child at rest
• Check the foot for embedded foreign body
• Assess for leg length discrepancy
• Look for muscle atrophy, tenderness, weakness or abnormal reflexes
• Neurological examination.

If no clear cause for limp is found on examination of the lower limbs or spine, examine the groin and abdomen.

Investigations

In a well child with < 3 days history of limp

• No investigations are required

In a sick child, seek advice from an ED senior doctor

• Bloods: FBC, CRP, ESR, blood cultures
• X-ray hip: lateral and AP pelvis
• Hip ultrasound may be required
• Discuss with paediatric orthopaedic team.

In children with fever or severe hip pain/spasm

• Seek advice from an ED senior doctor
• Blood tests: FBC, CRP, ESR, blood culture
• X-ray hip: lateral and AP pelvis
• Hip ultrasound may be required
• Lateral frog-leg view X-ray needed if considering SUFE (25% are bilateral, therefore X-ray both sides)

Differential diagnoses

Transient Synovitis (Irritable Hip)

• Most common cause of limping in pre-school children
• Diagnosis of exclusion
• Age range: 3 - 8 years
• Boys : Girls ratio 2:1

Perthes disease

• Age range: 4 - 12 years
• Boys : Girls ratio 4:1

Slipped Upper Femoral Epiphysis (SUFE)

• Age range: 10 - 15 years
• Boys 12 - 15 years
• Girls 10 - 13 years
• Boys : Girls ratio 4:1
• Typically overweight children

Management

• If either a fever or raised ESR is present, the patient is 8 times more likely to have an infection or an autoimmune process than if both parameters are normal
• If both these parameters are raised, more than 90% of cases will be due to an infectious or autoimmune cause.

Well children

• Discharge home
• Advise bed rest
• Regular non-steroidal anti-inflammatory drugs (e.g. Ibuprofen, Naproxen)
• Review in ED in 2 - 5 days
• Earlier if the child becomes febrile or the condition worsens.

Sick children

• Discuss with and admit under the orthopaedic team

Septic arthritis/osteomyelitis

• Discuss with and admit under the orthopaedic team
• Intravenous Antibiotics – consider (do not give without discussing with the orthopaedic team).

Perthes disease

• Discuss with the orthopaedic team
• Usually requires admission.

SUFE

• Discuss with and admit under the orthopaedic team
• Requires surgery.

Referrals and follow-up

• Children with hip pain for longer than 4 weeks can be referred to the Paediatric Rheumatology Team
• Ask their advice on the appropriate blood tests to do in the meantime.

Bibliography

1. Fundamentals of Pediatric Orthopedics
2. Staheli, Fundamentals of Pediatric Orthopedics By: Lynn T. Staheli 2015
3. Textbook of Pediatric Emergency Medicine. 6th ed. Fleisher GR, Ludwig S. Philadelphia: Lippincott Williams & Wilkins, 2010.
4. Textbook of Paediatric Emergency Medicine 2nd Edition Cameron Elesevier 2012
5. Nelson Textbook of Pediatrics: 20th Edition Robert M. Kliegman, Bonita M.D. Stanton, Joseph St. Geme, Nina F Schor Publisher: Elsevier