[AXIS IMAGING FOR KNEE ARTHROPLASTY - DO WE NEED THEM?]

Abstract

Introduction: Full-length standing radiographs provide a comprehensive assessment of the alignment of the entire lower extremity, widely used for surgical planning. These radiographs are not available in most imaging institutes, and knee radiographs are usually performed only in a standing position.

Aims: Our work aims to evaluate the accuracy of measuring aLDFA (anatomic lateral distal femoral angle) on standard short AP X-rays compared to long-standing X-rays.

Methods: A retrospective study was conducted with 200 sets of radiographs. Each set included a full-length AP lower extremity and a short AP knee radiograph from each leg. Each radiograph was examined blindly by two observers. The aLDFA (lateral distal femoral angles) were measured.

Results: The mean age of subjects was 71.17 years (6.37SD), BMI 32.98 (6.53SD), females represented 74.5% of the patients. No significance was found between short and long X-ray films for aLDFA ( p=0.69), and no significance was seen comparing the left to the right leg (p=0.592). the observers' agreement level was high. We observed a small size effect of 0.04.

Conclusions: Full-length radiographs are non-superior for preoperative planning for kinematic alignment total knee arthroplasty (TKA) regarding aLDFA.

Discussion: Our study results support the hypothesis that no difference exists between short and full-length radiographs in the aLDFA measurements.