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Current Issue - July 2017, Volume 11, Issue No. 2

Official Journal of Malaysian Orthopaedic Association and ASEAN Orthopaedic Association

A Comparison of Plain Radiography with Computer Tomography in Determining Coronal and Sagittal Alignments following Total Knee Arthroplasty


Introduction: Optimal coronal and sagittal component positioning is important in achieving a successful outcome following total knee arthroplasty (TKA). Modalities to determine post-operative alignment include plain radiography and computer tomography (CT) imaging. This study aims to determine the accuracy and reliability of plain radiographs in measuring coronal and sagittal alignment following TKA.

Materials and Methods: A prospective, consecutive study of 58 patients undergoing TKA was performed comparing alignment data from plain radiographs and CT imaging. Hipknee-angle (HKA), sagittal femoral angle (SFA) and sagittal tibial angle (STA) measurements were taken by two observers from plain radiographs and compared with CT alignment. Intra- and inter-observer correlation was calculated for each measurement.

Results: Intra-observer correlation was excellent for HKA (r>0.89) with a mean difference of <1.9°. The least intraobserver correlation was for SFA (mean r=0.58) with a mean difference of 8°. Inter-observer correlation was better for HKA (r>0.95) and STA (r>0.8) compared to SFA (r=0.5). When comparing modalities (radiographs vs CT), HKA estimations for both observers showed the least maximum and mean differences while SFA observations were the least accurate.

Conclusion: Radiographic estimation of HKA showed excellent intra- and inter-observer correlation and corresponds well with CT imaging. However, radiographic estimation of sagittal plane alignment was less reliably measured and correlated less with CT imaging. Plain radiography was found to be inferior to CT for estimation of biplanar prosthetic alignment following TKA.

Abstract   |   Reference

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The Malaysian Orthopaedic Journal is a peer-reviewed journal that is published three times a year in both print and electronic online version. The purpose of this journal is to publish original research studies, evaluation of current practices and case reports in various subspecialties of orthopaedics and traumatology, as well as associated fields like basic science, biomedical engineering, rehabilitation medicine and nursing.

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