Preoperative Three-dimensional CT Predicts Intraoperative Findings in Hip Arthroscopy

Abstract

Background Currently, plain radiographs and MRI are the standard imaging modalities used for diagnosing femoroacetabular impingement (FAI) and preoperative planning for arthroscopic treatment of FAI. The value of three-dimensional (3D) CT for these purposes is unclear. Questions/purposes We therefore determined the reliability of CT assessment of FAI and whether CT findings of hip disease predict arthroscopic findings. Methods We retrospectively assessed the preoperative CT scans of 118 patients who underwent primary hip arthroscopy. Intraoperative findings, including size of the cam lesion, presence of an acetabular labral articular disruption lesion, and one of four types of labral tear were recorded and compared with the retrospectively read CT findings. Results Agreement analysis between CT and intraoperative detection of FAI yielded kappa values of 0.48 for cam lesions and 0.16 for pincer lesions. Increasing values for the CT-based alpha angle correlated with increasing severity of arthroscopically assessed acetabular labral articular disruption grade. Each pattern of FAI predicted a specific labral tear type. Conclusions Our data suggest CT has moderate value in predicting mechanically based labral tear patterns, although better parameters for assessment of pincer lesions are needed. Diagnostic assessment of patients with suspected FAI may be improved with use of 3D CT. Level of Evidence Level III, diagnostic study. See the Guidelines for Authors for a complete description of levels of evidence.

Clinical and Morphologic Factors Associated with Suture Anchor Refixation of Labral Tears in the Hip

“…Up to 50% of crossover signs indicating acetabular retroversion on plain AP radiographs have shown not to be present on 3D CT scans [36]. Intraoperative findings of labral damage have been positively correlated with preoperative alpha angles measured on 3D CT scans, which is consistent with our study [14]. Konan found the frog lateral plain radiograph to significantly underestimate the alpha angle when compared to 3D CT scans [19].…”

Is the Acetabulum Retroverted in Slipped Capital Femoral Epiphysis?

“…Kitadai et al [15] compared LCEA measurement to the Visser method and found no difference at different SCFE severity levels, concluding LCEA can be accurately measured in a hip with SCFE. Interobserver variability ICCs reported in the literature are 0.83 for AV sup [6], 0.69 for AV cen [11], and 0.78 for LCEA [11] measured on CT. We used Levene's test to determine equality of variances among the three groups at both measurement locations. One-way ANOVA was used to identify differences in acetabular version among the three groups at both measurement locations.…”

Does Femoral Rotation Influence Anteroposterior Alpha Angle, Lateral Center-edge Angle, and Medial Proximal Femoral Angle? A Pilot Study

“…Abnormalities of morphologic features that can lead to FAI include cam abnormality on the femoral side and/or pincer overcoverage on the acetabular side [15,33]. Normal parameters for both of these have been defined for plain radiography and advanced imaging [2,5,7,14,19,29,35,37,41]. The alpha angle, Each author certifies that he or she has no commercial associations (eg, consultancies, stock ownership, equity interest, patent/licensing arrangements, etc) that might pose a conflict of interest in connection with the submitted article.…”

“…initially described by Notzli et al [25] and validated on axial oblique images of MRI [25] (and subsequently CT [14]), has recently emerged as a method of quantifying the cam lesion. The lack of universal availability of MRI and potential uncertain risks of radiation from CT have been limitations with these imaging modalities, forcing exploration of the measurement methods with biplanar radiographs [2,11,23,35] to ensure wider applicability for screening [12,34].…”