Synopsis
Localise a childhood limp safely, use age and tempo to prioritise diagnoses and identify infection, fracture, SUFE, malignancy and safeguarding concerns before labelling a benign gait disturbance.
- A limp is a presentation, not a diagnosis; first decide whether the child is systemically unwell, unable to bear weight or at immediate structural risk.
- Use age to prioritise without excluding: toddler fracture and infection in young children, Perthes in early school years and SUFE in adolescents.
- Ask the child to point with one finger, but examine the joints above and below, both hips, spine, abdomen, feet and skin because pain is often referred.
- Observe gait only when safe; never make a suspected SUFE, femoral-neck injury or severely painful child walk for diagnostic proof.
- No investigation may be reasonable in a well child with mild symptoms under seven days, comfortable weight bearing and a firm review plan.
- First-line tests for red flags are targeted radiographs and selected FBC, CRP, ESR and blood cultures; ultrasound detects effusion but not its cause.
- MRI is the reference investigation for occult fracture, osteomyelitis, pyomyositis, marrow tumour, early Perthes and spinal disease when localisation or radiographs are insufficient.
- Discharge only with a working diagnosis, permitted loading, analgesic dose, review time and explicit return advice for fever, worsening pain or reduced weight bearing.
Key red flags
Acute complete refusal to bear weight is a red flag at every age and needs an explanation beyond growing pains.
Fever, tachycardia, toxic appearance, hot swelling or severe passive-movement pain suggests bone or joint infection.
Night pain, weight loss, pallor, bruising, mass, lymphadenopathy or organomegaly raises leukaemia or bone tumour.
An adolescent with hip, thigh or knee pain and external rotation has possible SUFE and must not walk.
History inconsistent with development, delayed presentation, multiple injuries or concerning interaction requires safeguarding assessment.
Weakness, sensory change, abnormal reflexes or bladder or bowel symptoms localises to neurological or spinal disease and demands urgent imaging.
Investigation priorities
Identify fracture, SUFE, Perthes, tumour, deformity and late infection at the clinically localised site.
Management branches
The child is unwell, non-weight-bearing or has severe joint pain, neurovascular change or neurological findings.
- Assess ABCDE, observations and analgesia and stop unsafe walking or provocative testing.
- Obtain urgent paediatric and orthopaedic input, cultures and targeted radiographs, ultrasound or MRI.
- Immobilise fracture, make SUFE non-weight-bearing and start sepsis antibiotics without delay when indicated.
- Drain septic joint or abscess and protect neurological or vascular structures through the relevant emergency pathway.
The child is stable but the cause and anatomical origin remain uncertain.
- Use age, tempo and one-finger pain localisation, then inspect skin, foot, joints, spine and abdomen systematically.
- Examine both hips for any thigh or knee complaint and assess neurology and leg length.
- Observe gait only if safe and distinguish antalgic, abductor, short-limb and neurological patterns.
- Select investigations from the most consequential remaining differential rather than ordering a universal panel.