Smart Brace for Static and Dynamic Knee Laxity Measurement.

Area of Science:

• Biomedical Engineering
• Orthopedics
• Sports Medicine

Background:

• Over 500,000 anterior cruciate ligament (ACL) injuries are diagnosed annually in Europe.
• Current manual knee laxity assessments are subjective and provide limited information.
• Existing instrumental methods offer only partial static or dynamic laxity data.

Purpose of the Study:

• To develop an innovative smart knee brace for comprehensive knee laxity evaluation.
• To enable simultaneous quantitative assessment of rotational and translational laxity using a single device.
• To support objective diagnosis of ACL tears.

Main Methods:

• Development of a wearable smart knee brace integrating stretchable strain sensors and inertial measurement units (IMUs).
• Characterization of IMUs using a reference sensor and strain sensors.
• Pilot study comparing the smart brace's outcomes with a marker-based optoelectronic stereophotogrammetric system.

Main Results:

• IMU characterization showed agreement limits below 0.06 m/s² (accelerometer), 0.06 rad/s (gyroscope), and 0.08 μT (magnetometer).
• Average gauge factor for strain sensors was determined to be 2.169.
• Preliminary findings indicate the system's capability to discriminate ACL lesions, showing encouraging results.

Conclusions:

• The developed smart knee brace offers a promising solution for objective and quantitative knee laxity assessment.
• Simultaneous evaluation of rotational and translational laxity can enhance ACL injury diagnosis.
• Further clinical validation is required to confirm the system's real-world effectiveness.