Pivot shift intraoperative quantitative assessment using a smartphone accelerometer in ACL deficient knees.

Area of Science:

• Orthopedic Surgery
• Biomechanics
• Medical Device Technology

Background:

• The Pivot Shift (PS) test is crucial for assessing anterior cruciate ligament (ACL) deficiency.
• High inter-observer variability necessitates objective, quantitative measurement tools.
• Smartphone accelerometers offer a potential solution for reproducible PS assessment.

Purpose of the Study:

• To validate the reproducibility of intraoperative quantitative assessment of the PS using a smartphone accelerometer.
• To compare measurements between injured and uninjured knees.
• To evaluate the correlation of measurements with surgical stages.

Main Methods:

• A pilot study involving 12 ACL-injured knees and their contralateral healthy sides.
• PS test measured intraoperatively using a smartphone accelerometer by two independent observers.
• Reproducibility assessed via intraclass correlation coefficient (ICC) and compared across surgical steps.

Main Results:

• Excellent inter-observer reliability (ICC 0.99) and intra-observer reliability (ICC 0.89-0.97).
• Significant preoperative difference in tibial acceleration between injured (3.45 m/s²) and healthy knees (1.03 m/s²).
• Postoperative measurements showed no significant difference; acceleration correlated with PS IKDC grade.

Conclusions:

• Smartphone accelerometers provide a reproducible method for quantitative intraoperative assessment of PS.
• Measurements are influenced by surgical interventions during ACL reconstruction.
• Further validation with larger cohorts and other technologies is recommended.