A 13-year-old boy is brought to the clinic because of a 3-week history of worsening right hip and knee pain that causes him to limp. He denies any recent falls or direct trauma. Past medical history is negative. On physical examination, his body mass index (BMI) is 31 kg/m2 (calculated for age/sex as >97th percentile). When his right hip is passively flexed, the thigh spontaneously rotates externally. Internal rotation of the right hip is significantly limited and painful. Plain radiography of the hips reveals a posterior and inferior displacement of the right femoral head relative to the femoral neck.
Which of the following is the most appropriate next step in the management of this patient?
The correct answer is:
B) Immediate non-weight bearing and surgical stabilization
This patient is presenting with slipped capital femoral epiphysis (SCFE), a condition where the femoral head (epiphysis) slips posteriorly and inferiorly relative to the femoral neck through the growth plate. It classically occurs in obese adolescents during periods of rapid growth. The hallmark physical exam finding is the obligate external rotation of the hip during passive flexion. SCFE is a surgical emergency because continued weight-bearing can lead to further slippage or avascular necrosis (AVN) of the femoral head. The immediate management is to make the patient strictly non-weight-bearing, usually via wheelchair or crutches),followed by surgical fixation (typically in situ screw fixation) to prevent further displacement.
Answer choice A: Aspiration of the hip joint, is incorrect. This is used to diagnose septic arthritis, which would present with acute, severe pain, inability to bear weight, high fever, and elevated inflammatory markers. This patient's subacute presentation and lack of fever point toward a mechanical/developmental cause.
Answer choice C: Outpatient physical therapy, is incorrect. Applying mechanical stress through exercise or physical therapy to an unstable SCFE is dangerous and significantly increases the risk of complete slip and AVN.
Answer choice D: Pavlik harness application, is incorrect. The Pavlik harness is used for infants with developmental dysplasia of the hip (DDH). It has no role in the management of adolescent hip disorders.
Answer choice E: Reassurance and observation, is incorrect. SCFE does not resolve on its own. Without surgical intervention, the deformity will likely progress, leading to permanent gait abnormalities and early-onset osteoarthritis.
Key Learning Point
SCFE is a common cause of hip or knee pain in obese adolescents. The diagnosis is confirmed via X-ray (look for the femoral head falling below Klein’s line). Management must be immediate: stop weight-bearing and proceed to surgical stabilization to prevent avascular necrosis.
