Abstract
Background: CT scanning is an essential part of the preoperative planning process prior to surgical fixation of acetabular fractures. Considerable disparity exists between the clinical and radiological outcome following open reduction and internal fixation of these fractures. It is suggested that this disparity is due to poor assessment of the quality of reduction using plain radiographs alone.
Aim: To investigate the role of post-operative CT scanning following ORIF of acetabular fractures.
Methods: Prospective study commenced in January 2000 of all patients in our institution undergoing internal fixation of acetabular fractures. Post operative axial CT scans were compared with plain radiographs (AP pelvis and 45 degree oblique Judet views) with regard to the sensitivity to detect articular fracture reduction in terms of gap displacement and step deformity or offset. A simplified binary measurement of radiological outcome was used stratifying radiological result into anatomical and non-anatomical. Three observers independently reviewed the plain radiographs and CT scans at two separate time points and categorized the radiographic outcome as described. The interobserver reproducibility and intraobserver reliability of these measurements was expressed as a kappa statistic. In addition in those patients greater than 18 months following surgery we attempted to correlate the radiographic with the clinical outcome using the Harris hip score and the SF-36 score.
Results: 20 patients were recruited. Plain films were equieffective in detecting post-operative articular fragment displacement (p=0.24). The interobserver and intraobserver agreement between the radiological outcome measurements were good with respective kappa values of 0.61 and 0.65. There was a weak association between clinical and radiographic outcome as ascribed by post operative CT scans.
Conclusion: While there may be an argument for the use of post operative CT scanning acetabular fractures in selective cases, we did not find any significant benefit of CT scans over plain radiographs in the assessment of reduction or radiological outcome following these injuries. Hence we do not routinely advocate their use in the post operative setting.
The abstracts were prepared by Emer Agnew. Correspondence should be addressed to Irish Orthopaedic Association, Secretariat, c/o Cappagh National Orthopaedic Hospital, Finglas, Dublin 11, Ireland.
