Definition
A limp in a child is a common presentation and may arise from pain, deformity, weakness or neuromuscular dysfunction. The approach must always identify time-critical causes such as septic arthritis, osteomyelitis, trauma, slipped capital femoral epiphysis and malignancy.
History
Establish:
- Age of the child
- Onset: acute or chronic
- Pain, fever or systemic features
- Trauma
- Ability to bear weight
- Location of pain: hip, thigh, knee, leg or foot
- Recent infection
- Nocturnal pain or weight loss
- Underlying neuromuscular or inflammatory disease
Examination
- Observe gait and willingness to bear weight
- Examine the hip first, even if pain is felt at the knee
- Assess all lower-limb joints and the spine
- Look for swelling, erythema, deformity or muscle wasting
- Record temperature and systemic condition
- Complete a neurovascular examination
Important red flags
- Fever or toxicity
- Refusal to bear weight
- Severe pain with joint movement
- Night pain
- Weight loss or unexplained bruising
- Persistent symptoms without clear diagnosis
Age-based differential diagnosis
Toddler and preschool child
- Transient synovitis
- Septic arthritis
- Osteomyelitis
- Developmental dysplasia or sequelae
- Toddler’s fracture
- Discitis
- Neuromuscular conditions
School-age child
- Transient synovitis
- Perthes disease
- Septic arthritis or osteomyelitis
- Overuse or trauma
- Juvenile idiopathic arthritis
- Malignancy
Adolescent
- Slipped capital femoral epiphysis
- Apophyseal injury or overuse injury
- Stress fracture
- Septic arthritis
- Inflammatory arthritis
- Tumour
Septic arthritis versus transient synovitis
Features favouring septic arthritis include:
- Fever
- Refusal to bear weight
- ESR raised
- CRP raised
- Elevated white cell count
The Kocher criteria are commonly used as a guide but should not replace clinical judgement.
Investigations
- Plain radiographs of the suspected region and pelvis when appropriate
- Ultrasound for hip effusion
- FBC, ESR and CRP when infection or inflammation is suspected
- MRI when osteomyelitis, occult fracture, discitis or malignancy is suspected
- Joint aspiration when septic arthritis is suspected
Key diagnoses not to miss
Septic arthritis
Requires urgent diagnosis and drainage plus antibiotics.
Slipped capital femoral epiphysis
Think of this in an adolescent with hip, thigh or knee pain and restricted internal rotation.
Perthes disease
Typically presents with an insidious limp in a child aged 4–8 years.
Malignancy
Consider in persistent pain, night pain, constitutional symptoms or abnormal blood results.
Initial management
Management depends on the cause. Provide analgesia, limit weight-bearing where necessary, and escalate urgently when infection, unstable SCFE or malignancy is suspected.
Original outline
