Case of the Month – April 2020
By Dr Phelim Doyle
History and findings:
The patient, a 5 year old boy, was referred on 27.8.19 for an x-ray of the left tibia and fibula with a history of pain. The examination was normal.
He saw another doctor the next day and was referred for a left hip US as a diagnosis of left hip synovitis was suspected. The ultrasound showed a small left hip joint effusion with increased vascularity within the capsule, this was reported as a reactive synovitis with a recommendation for clinical correlation to exclude infective features.
The patient returned on 4.2.20 with a recurrence of symptoms with a request for left hip US and x-rays. The ultrasound was unremarkable but the x-rays showed flattening of the left femoral capital epiphysis and a prominent lucency at the metaphysical margin with the growth plate, Perthe’s disease. Follow up x-rays on the 7.4.20 show progression of the bony changes of Perthe’s disease.
X-ray of the left hip
Perthe’s affects children between the ages of 3 and 11 years, most common between 4 and 8, five times more common in boys, and is due to avascular necrosis at the femoral head. The body eventually restores the blood supply and healing occurs, often with residual deformity and eventual secondary osteoarthritis.
Treatment depends on age and the stage of the disease, younger children generally do better. Early stages may be treated conservatively or with casting. More advanced changes may require osteotomy and internal fixation.