Operative Fluoroscopic Correction Is Reliable and Correlates With Postoperative Radiographic Correction in Periacetabular Osteotomy

Abstract

Background Intraoperative fluoroscopy is commonly used to both guide the osteotomy and judge correction of the acetabular fragment in periacetabular osteotomy (PAO). Prior studies that have compared intraoperative fluoroscopic correction with postoperative radiographic correction were small studies that did not report intra-or interreader reliability. Questions/purposes (1) What is the correlation between intraoperative fluoroscopic correction in PAO compared with the correction seen on postoperative radiographs? (2) What is the reliability of radiographic measures of correction in PAO? Methods We performed a retrospective study of 121 patients (141 hips) who underwent PAO for symptomatic hip dysplasia at a tertiary referral center. Patients were included in the study if they had preoperative radiographs, intraoperative fluoroscopy, and minimum 6-week postoperative radiographs. Of the 272 PAO procedures performed in this time period, 61 patients who underwent PAO for retroversion and five patients with a history of Perthes disease were excluded as a result of the inability for these radiographic measures to judge fragment correction in PAOs for retroversion and the difficulty in measurement in post-Perthes deformity. Of the 206 PAOs performed for symptomatic acetabular dysplasia, 65 (32%) could not be analyzed because they lacked appropriate preoperative films, leaving 141 PAOs in 121 patients for analysis. The patients lacking appropriate preoperative films had them performed at an outside facility or had plain films that have since been destroyed. The lateral center-edge angle (LCEA) and acetabular index (AI) on the fluoroscopic views and postoperative radiographs were measured by two authors. The concordance between the amount of correction on intraoperative fluoroscopy and minimum 6-week postoperative measurements was analyzed using the concordance correlation coefficient (r c ) and a Bland-Altman analysis. Intra-and interrater reliability was calculated between measurements.

What Is the Reliability and Accuracy of Intraoperative Fluoroscopy in Evaluating Anterior, Lateral, and Posterior Coverage During Periacetabular Osteotomy?

“…Fluoroscopy is commonly used to judge fragment correction during PAO to correct acetabular dysplasia. Accuracy of fluoroscopy in judging the correction obtained has been demonstrated for LCEA, TA, and ACEA [12,22]. Our study further validates these three measures as reliable and accurate for judging correction intraoperatively with a mean difference of # 2°for all three measures.…”

“…Therefore, it did not address interrater reliability and was underpowered to address intrarater reliability [12]. A larger study by one of the current authors evaluated the use of the LCEA and TA for intraoperative correction and showed similar intra-and interrater reliability as those reported here for the LCEA and TA [22]. However, this study only looked at lateral coverage with LCEA and TA.…”

“…A similar small study with a single reader concluded that the lateral center-edge angle (LCEA), Tönnis angle (TA), and anterior center-edge angle (ACEA) were accurate fluoroscopic measures of fragment correction in a small sample with a single reader [12]. A larger study confirmed the reliability and accuracy of judging lateral correction with LCEA and TA to judge lateral coverage in a larger sample of patients with multiple readers [22]. However, the study only addressed correction of lateral coverage and not anterior or posterior coverage of the femoral head.…”

“…The study was performed in 2017 and 2018. This period was chosen to approximate the study size in the largest study on the topic to date [22]. Patients were included if they had a diagnosis of acetabular dysplasia (determined by an LCEA or ACEA of < 20°), preoperative and postoperative standing AP and false profile pelvic radiographs, and fluoroscopy images including final images of a PA and false profile views with hardware in place in our imaging system.…”

“…Contemporary techniques of PAO for acetabular dysplasia commonly use fluoroscopy to guide osteotomies and to judge the correction of the acetabular fragment. Prior studies reported on the accuracy of fragment correction during PAO [11,12,22]. A small study reported on 22 patients undergoing PAO and found no differences between intraoperative radiographic and fluoroscopic measurements and higher radiation doses with radiography [11].…”