An 18-month-old boy is brought to the orthopedic outpatient department by his parents with complaints of a waddling gait and asymmetric skin folds on the thighs noticed over the past 2 months. Birth history reveals he was a breech presentation. On examination, the left hip shows a positive Trendelenburg sign, limited abduction (40 degrees), and a palpable hip clunk on Ortolani maneuver. Plain radiographs of the pelvis show a shallow acetabulum on the left with the femoral head displaced superolaterally. What is the most appropriate management at this stage?