(471) The relationship between body mass index and fluoroscopy time during intra-articular hip injections: a multicenter cohort study

Abstract

Hip pain is a common complaint and is often related to osteoarthritis (OA). When conservative management is ineffective for managing pain, intra-articular (IA) injections often with corticosteroid are typically performed. Ultrasound guidance during IA hip injection can be used in order to avoid radiation exposure; however, true IA injection cannot be confirmed without the use of contrast and fluoroscopy, and ultrasound guidance may be more challenging or impossible in patients with higher body mass index(BMI). Thus, fluoroscopic guidance is often used in obese patients. However, the relationship between BMI and fluoroscopy time during IA hip injections has not been investigated. The present study sought to define this relationship in retrospective cohort study at three outpatient pain centers. Median and standard deviation fluoroscopy time. Comparisons were made between body mass index categories of normal (18.5 - 24.9 kg/m2), overweight (25.0 - 29.9 kg/m2), and obese (≥30.0 kg/m2). Statistical significance was set at p=0.01 due to comparison of three groups. A total of 559 IA hip injections were analyzed. Patients had a mean age of 58 (standard deviation [SD] 14) years and 63% were female. There was no significant difference in fluoroscopy time when comparing BMI categories (p=0.02). However, when trainees were not involved in the injection, fluoroscopy times were significantly longer with increasing BMI, with obese patients requiring higher fluoroscopy time (p=0.01). The findings of this study indicate that fluoroscopy time during IA hip injection is increased with greater BMI, though this relationship is not present when trainees are involved due to comparatively longer fluoroscopy times in patients with lower BMI. Future study of the impact of BMI on radiation dose during fluoroscopically-guided IA hip injections is needed.