, Volume 470, Issue 7, pp 1950-1957
Date: 13 Apr 2012

Preoperative Three-dimensional CT Predicts Intraoperative Findings in Hip Arthroscopy

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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.


We therefore determined the reliability of CT assessment of FAI and whether CT findings of hip disease predict arthroscopic findings.


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.


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.


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.

One author (BTK) has consultancies (Pivot Medical – Sunnyvale, CA; A2 Medical – Dallas, TX; Smith and Nephew Endoscopy – Andover, MA) and stock ownership (Pivot Medical – Sunnyvale, CA) that may pose a conflict of interest. All other authors certify that neither he, nor a member of their immediate family, has consultancies, stock ownership, equity interest, or patent/licensing arrangements in any companies that may pose a conflict of interest.
All ICMJE Conflict of Interest Forms for authors and Clinical Orthopaedics and Related Research editors and board members are on file with the publication and can be viewed on request.
This work was performed at the Hospital for Special Surgery, New York, NY, USA.