2023 ISAKOS Biennial Congress ePoster
The Accuracy of Portable Accelerometer-Based Navigation System for Tibial Alignment can be Reliable in Total Knee Arthroplasty for Obesity Patients. A Propensity Score Matching Analysis
Kazumi Goto, MD, Minato-Ku, Tokyo JAPAN
Jinso Hirota, MD, Tokyo JAPAN
Yoshinari Miyamoto, Tokyo JAPAN
Yozo Katsuragawa, MD, PhD, Shinjuku-Ku, Tokyo JAPAN
Mitsui Memorial Hospital, Chiyoda-ku, Tokyo, JAPAN
FDA Status Not Applicable
Summary
When the accuracy of tibial bone cutting in total knee arthroplasty with a portable accelerometer-based navigation system was compared using propensity score matching, there was no statistically significant difference between the group with a BMI of 30 or greater and the group with a BMI of less than 30 in both coronal and sagittal plane.
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Abstract
Purpose
A portable accelerometer-based navigation system can be useful as a measure of obtaining target alignment. Tibial registration is based on the medial and lateral malleoli; however, identification of landmarks may be difficult in obese patients whose bones are not easily palpable from the body surface. The purpose of this study was to compare tibial component alignment obtained using a portable accelerometer-based navigation system (Knee Align 2) between obese (body mass index > 30 kg/m2) and control groups and to validate the accuracy of bone cutting in obese patients.
Methods
A total of 210 knees that underwent primary TKAs with Knee Align 2 system were included. After 1:3 propensity score matching, there were 32 and 96 knees in over BMI 30 (group O) and under BMI 30 (group C), respectively. The absolute deviation of the tibial implant from the intended alignment were evaluated in both coronal plane (HKA; hip-knee-ankle angle, MPTA; medial proximal tibial angle) and sagittal plane (PS; posterior tibial slope). The rate of “inlier” in each cohort, defined as a tibial component alignment within 2° from the intended alignment, was investigated.
Results
In the coronal plane, the absolute deviation of the HKA and MPTA from the intended alignment was 2.2 ± 1.8° and 1.8 ± 1.5° in group C and 1.7 ± 1.5° and 1.7 ± 1.0° in group O (P =1.26, and 0.532). In the sagittal plane, the absolute deviation of the tibial implant was 1.6 ± 1.2° in group C and 1.5 ± 1.1° in group O (P = 0.570). The rate of inlier was not significantly different between group C and group O (HKA; 64.6 vs 71.9 %, P=0.521, MPTA; 67.7 vs 78.1%, P=0.372, PS; 82.2 vs 77.8%, P=0.667).
Conclusion
The accuracy of tibial bone cutting for obese group was comparable to control group. An accelerometer-based portable navigation system can be useful for obese population to achieve target tibial alignment.