MON-791 Recurrent Transient Osteoporosis of the Hip

Abstract Disclosure: S. Harjanto: None. Background: Transient osteoporosis is known by several different names such as bone marrow edema syndrome, complex regional pain syndrome, or transient demineralization. It describes a reversible and self-limiting cause of acute, non-traumatic joint pain associated with characteristic MRI findings and with transient decrease in BMD. Treatment with bisphosphonates, calcitonin and teriparatide has been reported (1). Introduction: A 49-year-old man with no history of fracture presented to clinic with concerns of bone health after a recent MRI of his left hip reported ‘transient osteoporosis’. He developed acute left hip pain two months ago after a regular yoga session. The pain was aggravated by weight-bearing and had worsened over the first month. Examination revealed a quiescent left hip joint without any warmth, swelling, tenderness or erythema. He was ambulant with crutches, with no signs of Cushing’s syndrome or hyperthyroidism. Laboratory tests, including 25-OH vitamin D, ALP, free T4, TSH, calcium and phosphate, were all within normal limits. Pelvis radiograph performed was normal. Similar pain occurred in patient’s right hip two years ago, which resolved completely within five months. He was treated with alendronate, calcium and vitamin D supplements, and a period non- weight bearing with the use of crutches. MRI performed at that time reported ‘marrow edema’ of the right femoral head. Based on this experience, patient self-initiated the use of crutches to rest the left hip and had an MRI hip repeated. MRI hip demonstrated T1 hypointensity, T2 and STIR heterogenous signal intensities with no obvious cortical irregularity or subchondral collapse involving the head and neck regions of left femur with minimal adjacent myofascial edema. Comparison of his old MRI done two years ago showed similar findings over the right femoral region, typical of transient osteoporosis, which resolved completely on interval MRI five months later. He was therefore given Alendronate, calcium and vitamin D supplements again, and advised to continue non-weight bearing. Ten weeks later, DXA showed decreased BMD in the osteopenic range (T-score = -1.3 for left femoral neck). At four months from onset, his pain had significantly improved. He was advised to progressively increase weightbearing on his left lower limb. Conclusion: Transient osteoporosis needs to be considered in patients who present with atraumatic joint pain. Management is mainly supportive with possible use of bisphosphonates. It is self-limiting and tends to resolve without any sequelae. We describe a case of transient osteoporosis treated with alendronate. Reference 1. Asadipooya, K., Graves, L., & Greene, L. W. (2017). Transient osteoporosis of the hip: review of the literature. Osteoporosis International, 28(6), 1805-1816. Presentation: Monday, July 14, 2025