Background: Surgical hip reduction is an accepted treatment option for infantile developmental dysplasia of the hip (DDH) but may be complicated by the development of osteonecrosis, recently re-termed proximal femoral growth disturbance (PFGD) . Since the etiology of PFGD is likely related to compromised vascular supply to the femoral head, the need exists for an intraoperative method of assessing changes in femoral head perfusion prior to irreversible injury. This study sought to utilize contrast-enhanced ultrasound (CEUS) to assess intraoperative changes in perfusion following surgical reduction for infantile DDH, with the ultimate goal of predicting and eventually preventing PFGD. Methods: In this prospective study, CEUS was performed before and immediately after surgical reduction and spica casting in infants undergoing surgery for DDH between 4 and 18 months of age. Delta projections were used to quantitatively analyze changes in perfusion, and a statistical analysis was performed to assess the relationships between patient factors, including casting position, and changes in epiphyseal perfusion. Results: The study population of 32 patients included 34 hips, comprising 30 hips of female patients (88.2%) and 4 hips of male patients (11.8%), with a mean age and standard deviation of 9.3 ± 3.3 months. A lower perfusion index following surgical reduction (p = 0.003) was seen in the majority (79.4%) of hips. In the remaining hips, a higher perfusion index was observed following reduction (p = 0.03). The greatest significant decreases in perfusion index were observed in the central region of the femoral head epiphysis (p = 0.002), followed by the peripheral region of the femoral head epiphysis (p = 0.03). Axial abduction was correlated with a post-reduction decrease in perfusion index (r = 0.35; p = 0.04). There was a moderately positive correlation between body mass index (BMI) and a post-reduction change in perfusion index (r = 0.45; p = 0.01). Conclusions: There was wide variation in post-reduction changes in femoral head perfusion after surgical hip reduction and spica casting for infantile DDH, with a gradient of change across the regions of the femoral head. In addition, BMI and in-cast hip position seemed to influence perfusion changes. With continued analysis of these relationships and longer follow-up from our ongoing prospective investigation, we aim to identify the risk factors for PFGD development. Level of Evidence: Therapeutic Level II . See Instructions for Authors for a complete description of levels of evidence.
Kebeh et al. (Mon,) studied this question.