Prevalence of Transient Osteoporosis of the Hip Among Patients Presenting With Hip Pain in a Major Tertiary Hospital in Saudi Arabia.

Background: Transient osteoporosis of the hip, or acute bone marrow edema syndrome, is a rare condition characterized by a decrease in bone mineral density of the proximal femur, which resolves with conservative management over 6-24 months. At presentation, the patient complains of sudden onset of localized pain in the hip, which is aggravated by weight-bearing. However, the prevalence and risk factors for this condition are still unclear. Objective This study aims to identify the prevalence of transient osteoporosis of the hip among patients who present with hip pain and underwent magnetic resonance imaging of the hip.

Method: This is a retrospective investigation that involved collecting data from patients' records in a tertiary hospital in Saudi Arabia. Included candidates were patients who presented with hip pain, had an MRI done between 2016 and 2019 inclusive, and were older than 14 years. The collected data involved the age and gender of patients, the hip's affected side, and the diagnosis. Data analysis was executed through SPSS version 26 (IBM Corp., Armonk, NY).

Results: Three hundred and fourteen patients matched our inclusion criteria. The prevalence of transient osteoporosis of the hip was 2.5%. All of them were males and half were above 40 years, 50% had pain in the left side, and 75% had a small joint effusion. The femoral head was the most affected part of the joint in patients with transient osteoporosis of the hip. Among our patients, the most common cause of hip pain was gluteus medius tendonitis (12.9%), where 33.1% of patients with hip pain had normal examination and investigations, and 15.2% had more than one condition. Risk factors for transient osteoporosis of the hip are pain in the left hip joint (p-value=0.023) and an age between 41 and 50 years (p-value=0.012).

Conclusion: The prevalence of transient osteoporosis of the hip is low, yet it requires confirmation by studies with a more robust design. Males older than 40 years and left-side hip pain are at higher risk.