Follow-up of a 32-year-old female presenting with symptoms of hip impingement after idiopathic ONFH: panel a: plain radiograph early in the course of the disease showing partial collapse of femoral head; panel b: plain radiograph later in the course of disease showing cam deformity appearing due to remodelling; panel c: patients had symptoms of impingement during hip flexion and rotations; panel d: MRI scan early in the course of the disease-confirming changes of ONFH; panels e and f: CT scan of the same patient showing the cam deformity; panel g: intraoperative picture showing cam deformity at femoral head–neck junction; panel h: intraoperative picture after femoral head osteochondroplasty; panels i and j: post-operative radiographs showing restoration of femoral head sphericity; panels k and l: post-operative follow-up images showing restoration of hip range of motion.