Gait Variability Structure Linked to Worse Cartilage Composition Post-ACL Reconstruction.

Area of Science:

• Orthopedics
• Biomedical Engineering
• Radiology

Background:

• Aberrant gait variability is common after anterior cruciate ligament reconstruction (ACLR).
• The relationship between gait variability and early cartilage changes, indicative of osteoarthritis, remains unclear.
• Femoral articular cartilage composition can be assessed using T1ρ magnetic resonance imaging (MRI).

Purpose of the Study:

• To investigate the association between femoral articular cartilage T1ρ MRI relaxation times and gait variability in individuals post-ACLR.
• To determine if altered cartilage composition correlates with specific patterns of kinematic variability during walking.

Main Methods:

• T1ρ MRI and 3D motion capture were used to assess cartilage composition and knee kinematics in 22 ACLR participants.
• Femoral cartilage was segmented, and interlimb ratios (ILR) of T1ρ values were calculated to compare ACLR and uninjured limbs.
• Kinematic variability structure (KV structure) was quantified using sample entropy for frontal and sagittal plane movements.

Main Results:

• A significant association was found between reduced frontal plane KV structure and greater T1ρ ILR in the anterior lateral and medial femoral condyles.
• Reduced sagittal plane KV structure was also associated with greater T1ρ ILR in the anterior lateral femoral condyle.
• These findings indicate that less variable knee motion correlates with poorer cartilage composition post-ACLR.

Conclusions:

• The association between decreased kinematic variability structure and worse cartilage proteoglycan density suggests a link to deleterious joint tissue changes.
• Reduced knee kinematic variability structure may serve as a mechanism connecting aberrant gait patterns to the early development of osteoarthritis after ACLR.