Osteoporosis transitoria de cadera - reporte de caso

Transitory osteoporosis of the hip (TOH) is a very infrequent pathology that affects the proximal end of the femur. It occurs in middle-aged patients and is also described during pregnancy, usually in the third trimester. It is a process of unknown (idiopathic) etiology, of benign and self-limited evolution. Its diagnosis is imaging and must be distinguished particularly from an initial stage of avascular bone necrosis (ABN), whose prognosis and treatment differs substantially. In addition, we should keep in mind, among the differential diagnoses to infectious diseases (septic arthritis), tumor and idiopathic condrolysis. Case presentation: 33 year old male patient, no medical history. He consulted referring pain in the left inguinal region for a month and a half of evolution, without triggering trauma. He had conducted prior consultations, which included normal radiological studies; indicating restriction of activities and anti-inflammatory analgesics. In the history he reported that he practiced martial arts in a recreational way and that the pain began suddenly, of moderate and persistent intensity, intensifying with gait or climbing stairs; decreasing with seating and recumbency. On physical examination, he located the pain at the intra-articular level in the left hip, increased with internal rotation and flexion, without achieving complete mobility by voluntary defense. Radiographs of the pelvis (forehead) and both hips (forehead and axial) showed no abnormalities. Magnetic resonance imaging (MRI) demonstrated the presence of a medullary bone edema in the left proximal femoral epiphysis, compatible with TOH. Hematological studies, including bone markers were normal. Conservative treatment with discharge (crutches), calcium, vitamin D, bisphosphonates and analgesics was indicated. After a favorable clinical and imaging evolution (control with Rx and MRI), at eight weeks he returned to his usual activities. It is unlikely to differentiate clinically this pathology from other processes that compromise the hip joint. Despite being an infrequent entity with a good prognosis, its differential diagnosis must be taken into account, especially in the middle ages of life and pregnant patients. It is important for early diagnosis the use of MRI when circumstances allow.