A GIRL WITH A LIMP
History
Janis is a 12-year-old girl who presents to the paediatric rapid referral clinic with a 4-month history of an intermittent pain in her left hip with an associated limp. The pain is worse on running and she has stopped participating in her physical education classes at school. She occasionally takes ibuprofen that provides some pain relief. There is no history of trauma. She is generally well. She had a tonsillectomy and adenoidectomy at 5 years of age. Her mother has hypothyroidism.
Examination
She is apyrexial. She has an obvious limp. The left hip is flexed and there is restriction of internal rotation, abduction and flexion. There are no signs in the left knee or foot and there are no other joint abnormalities. The back is normal. There are no abdominal signs and no neurological signs in the lower limbs. Janis’s weight, at 55.4 kg, is between the 91st and 98th centiles and her height, at 1.34 m, is just below the second centile.
INVESTIGATIONS
Normal
Haemoglobin 10.8 g/dL 10.5–13.5 g/dL
White cell count 8.3 109/L 4.0–11.0 109/L
Neutrophils 5.2 109/L 1.7–7.5 109/L
Platelets 230 109/L 150–400 109/L
C-reactive protein 4 mg/L 6 mg/L
Erythrocyte sedimentation rate 14 mm/hour 0–15 mm/hour
Anteroposterior X-ray of the pelvis and hips – normal
Questions
• What are the common causes of a limp in a child?
• What is the diagnosis?
• What further investigations should be done?
• What is the treatment?
Medicine
A limp is a common problem in childhood. It is important to be aware that it can be due to an abnormality anywhere from the back to the foot. Causes of a limp in a child are best considered according to age:
• 0–3 years
– Trauma, e.g. fracture (may be accidental or non-accidental)
– Infection: septic arthritis, osteomyelitis or discitis
– Malignancy
– Developmental dysplasia of the hip
– Neuromuscular disease, e.g. cerebral palsy
• 4–10 years
– Trauma
– Transient synovitis (irritable hip)
– Infection
– septic arthritis, osteomyelitis or discitis
– Perthe’s disease
– Juvenile idiopathic arthritis
– Malignancy, e.g. leukaemia
– Neuromuscular disease, e.g. cerebral palsy
• 10–18 years
– Trauma
– Infection: septic arthritis, osteomyelitis or discitis
– Slipped upper femoral epiphysis
– Juvenile idiopathic arthritis
– Malignancy, e.g. osteogenic sarcoma
The diagnosis is a slipped upper femoral epiphysis (SUFE). SUFE is commoner in boys and in obese individuals. Pain can be felt in the groin, hip or thigh or there may be referred pain in the knee. Classically the affected hip is flexed and the leg is externally rotated. A small slip may be missed on the anteroposterior view and a lateral or frog leg view of the hip is therefore also necessary. The lateral X-ray shows displacement of the proximal femoral epiphysis relative to the femoral neck. Approximately 25 per cent of patients will also have a contralateral slip and the other hip must therefore be carefully assessed. A minority of patients with SUFE have an underlying endocrinopathy or metabolic abnormality (hypothyroidism, hypogonadism, growth hormone abnormalities, panhypopituitarism or renal osteodystrophy) and if this is suspected then the appropriate investigations should be performed. Janis is short and overweight and has a family history of thyroid disease. A more detailed examination demonstrated that she had a small goitre. Thyroid function tests revealed a free T4 of 9.2 pmol/L (12–22), a thyroid-stimulating hormone (TSH) of 64 mU/L (0.5–6.0) and thyroid peroxidase (TPO) antibodies of 1342 IU/ mL (0–34). These results are compatible with a diagnosis of Hashimoto’s (autoimmune) thyroiditis. Obese individuals should have their fasting glucose measured and this test should also be done on Janis. Janis should be admitted and told not to weight-bear. She should be referred urgently to the orthopaedic surgeons. Although it would seem that the SUFE has been present for 4 months, one can get an acute or chronic slip of the epiphysis that can lead to avascular necrosis of the femoral head. Surgery is therefore urgent and consists of pinning the femoral head to the femoral neck. Thyroxine should also be started.
KEY POINTS
• In SUFE, a lateral or frog leg view, as well as an anteroposterior view, of the hip is necessary to avoid missing minor slips.
• Urgent treatment is necessary in SUFE to try to avoid the complication of avascular necrosis of the femoral head
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