A novel physiological testing device to study knee biomechanics in vitro

Area of Science:

• Biomechanics
• Orthopedic Research
• Biomedical Engineering

Background:

• Studying knee joint biomechanics in vitro requires minimal constraint and physiological loading.
• A novel dynamic biomechanical knee system (BKS) was developed for this purpose.
• The system's feasibility and reproducibility were evaluated using an anterior cruciate ligament (ACL) lesion model in goat knees.

Purpose of the Study:

• To assess the feasibility and reproducibility of a novel dynamic biomechanical knee system (BKS).
• To demonstrate the system's capability in studying knee biomechanics using an anterior cruciate ligament (ACL) lesion model.

Main Methods:

• Six goat knees were subjected to simulated gait flexion/extension using a servo-motor.
• Artificial muscles applied physiological joint loads.
• Intra-class correlation coefficients (ICCs) assessed inter-test reliability, and paired t-tests compared intact vs. ACL-lesioned knees.

Main Results:

• Excellent inter-test reliability was found for varus/valgus (ICC=0.93), rotation (ICC=0.94), and translation in all directions (ICC=0.90-0.94).
• ACL-lesioned knees showed a significant, more than two-fold increase in joint center translation in frontal, side, and upward directions (p<0.018).

Conclusions:

• The novel five-degrees-of-freedom BKS reproducibly assesses knee motion under physiological loading.
• The system enables detailed biomechanical studies of knee defects and surgical treatments.
• Goat knees demonstrated natural movement pathways within the BKS, validating its utility.