DOS 2018

DOS Kongressen 2018 · 151 RELIABILITY OF STRESS RADIOGRAPHY IN QUANTIFICATION OF CORONAL LAXITY FOLLOWING TOTAL KNEE ARTHROPLASTY. Andreas Kappel, Nielsen Poul Torben, Odgaard Anders, Laursen Mogens Aalborg/Farsø, Aalborg University Hospital; Gentofte, Copenhagen University Background: Instability is one of the main causes for early failure following to- tal knee arthroplasty (TKA), and the frequency of revisions due to instability is rising in both national and international registries. The reliability of clinical soft tissue laxity examination is proven unsatisfactory and may be biased by patient complaints. Soft tissue laxity can be quantified with stress radiography, where the degree of stability between the components is measured as an angulation. Purpose / Aim of Study: To examine the reliability of coronal stress radiogra- phy following TKA. Materials and Methods: 17 cases with uncomplicated TKA were examined with coronal stress radiograph under both varus- and valgus-stress. In exten- sion, the Telos device was applied. In flexion, the epicondylar view with a hori- zontal stress was used. All procedures were repeated (test/re-test). Findings / Results: Mean laxity and SD were comparable to values published earlier. Pearson correlation coefficient, mean and SD for the differences in angu- lation between the repeated radiographs were as follows. Extension and valgus stress, cc=.97, mean .140, SD .620. Extension and varus stress, cc=.97, mean .180, SD .530. Flexion and valgus stress, cc=.95, mean .20, SD .820. Flexion and varus stress, cc=.77, mean .340, SD 2.90. In flexion and varus stress the angulations measured was larger and both rotation and translation between the components became evident on the stress radiographs. Conclusions: Coronal stress radiography is a reliable method to judge soft tis- sue laxity following TKA. The method is clinically applicable and may be a useful tool in both postoperative evaluation and in research. 92.