Using a 3D handheld scanner to capture trochlear groove shape: proof of concept study

Area of Science:

• Orthopedic surgery
• Biomedical engineering
• Medical imaging

Background:

• Patellar instability is often treated with trochleoplasty, a surgical modification of the trochlear groove.
• Accurate, real-time analysis of the trochlear groove is crucial for effective surgical planning and patient-specific correction.

Purpose of the Study:

• To evaluate the reliability and repeatability of using a handheld scanner to measure key trochlear parameters.
• To assess inter- and intra-rater reliability for trochlear depth, sulcus angle, trochlear facet ratio, trochlear angle, and lateral trochlear inclination angle using knee models.

Main Methods:

• Three-dimensional scanning of three knee models by two independent investigators.
• Creation of reference models, surface matching, and analysis using custom software to extract trochlear parameters.
• Intraclass correlation coefficient (ICC) was used to determine test-retest reliability.

Main Results:

• Good interobserver reliability was observed for trochlear depth, sulcus angle, trochlear angle, and lateral trochlear inclination angle.
• The trochlear facet ratio showed lower reliability in one model.
• After outlier removal, ICC values were moderate to excellent for 73.34% of measurements, with trochlear depth demonstrating the highest reproducibility.

Conclusions:

• A handheld scanner, coupled with supportive software, is a feasible tool for measuring trochlear parameters.
• The system demonstrates good to excellent inter- and intra-observer reliability, supporting its use in surgical planning for patellar instability.