The Pathophysiology of Primary Hip Osteoarthritis may Originate from Bone Alterations
A 62-year-old woman, 155.5 cm tall and weighing 68.0 kg, with no past history visited our hospital. At her first visit, she complained of slight locking symptoms with accompanying right hip pain after a long walk during a trip and bilateral knee pain while walking and reclining in a lateral recumbent position. Plain radiographs of the bilateral knee joints showed advanced-stage OA, while the right hip joint did not show OA features (KL grading 0, Fig. ). Physical examination revealed restricted abduction range of motion (ROM) in her right hip. A month after the onset of pain, hip MRI showed broad and heterogeneous low intensity by T1W and high intensity by T2-STIR (Fig. , ). Two months after onset, her joint pain disappeared; however, a slight joint space narrowing in the femoral head was found on plain radiographs (KL grading I, Fig. ). Interestingly, her left hip joint, which was without pain, had already shown slight joint space narrowing, but no signal change on MRI (Figs. ).