2025 ISAKOS Biennial Congress ePoster
Use Of A Gyroscope Sensor To Assess A Pivot Shift Test In Acl Deficient Knees.
Seong-Hwan Kim, MD,Ph.D, MStat, Seoul KOREA, REPUBLIC OF
Yong-Beom Park, MD, PhD, Gwangmyeong-Si, Gyeonggi-Do KOREA, REPUBLIC OF
Chung-Ang University Hospital, Seoul, Seoul, KOREA, REPUBLIC OF
FDA Status Not Applicable
Summary
Gyroscope sensor could be used as an objective tool to diagnose and categorize the pivot shift grade.
ePosters will be available shortly before Congress
Abstract
Purpose
The pivot shift (PS) test is commonly used to diagnose and evaluate the dynamic instability of the knee joint in cases of anterior cruciate ligament (ACL) tear. The purpose of this study is to evaluate the diagnostic value of gyroscope and to determine the cut-off values for high-grade anterolateral rotatory laxity in complete anterior cruciate ligament (ACL)-deficient knees.
Methods
Twenty-four patients with complete ACL-deficient knees, undergoing ACL reconstruction, were enrolled in the study. Only patients with high grade PS test (≥grade 2) under anaesthesia were included for this study. The PS test was performed using a smartphone attached to Gerdy’s tubercle. Rotation rate during the PS test were recorded using the smartphone gyroscope application. Intra-observer and inter-observer reliability of the test among the two observers were evaluated. Changes of rotation rate were compared between the injured and normal knees. Diagnostic utility of the smartphone gyroscope was examined by a receiver operating characteristic curve analysis. The Y axis revealed the rotation of knee axial plane, the Z axis revealed the knee flexion angles, and the X axis revealed the knee valgus/varus angle. (Figure 1)
Results
The change of rotation rate was higher in the ACL-deficient knees than in normal knees. The mean change of rotation rate in Y axis was 3.6±6.5 rad/s in ACL-deficient knees and -0.7±1.5 rad/s in normal knees (p=0.009). The mean change of rotation rate in Z axis was 0.5±1.8 rad/s in ACL-deficient knees and -0.03±0.5 rad/s in normal knees (p=0.155). The mean change of rotation rate in absolute value was 5.5±4.5 rad/s in ACL-deficient knees and 3.4±1.4 rad/s in normal knees (p=0.036).(Figure 2) Sensitivity was 62.5% and specifcity was 83.4% for the change of rotation rate required to detect ACL injury, with >0.96 rad/s in Y axis.(AUC,0.726, p=0.004) Sensitivity was 62.5% and specifcity was 75.0% for the change of rotation rate required to detect ACL injury, with >3.5 rad/s in absoluate.(AUC,0.693, p=0.013) Intra-observer and inter-observer reliability were good for the smartphone gyroscope. (ICC,>0.8)
Conclusions
The results show that a gyroscope can be used to evaluate the PS objectively to diagnosis of ACL injury.