A navigation-based analysis of native knee collateral ligament length change patterns in function of CPAK...

Area of Science:

• Orthopedics
• Biomechanics
• Arthroplasty

Background:

• Total knee arthroplasty (TKA) requires precise soft tissue balancing.
• Native knee collateral ligament behavior varies with coronal plane alignment phenotypes (CPAK).

Purpose of the Study:

• Investigate native medial collateral ligament (MCL) and lateral collateral ligament (LCL) elongation patterns across CPAK types.
• Inform TKA soft tissue balancing strategies by correlating alignment with ligament behavior.

Main Methods:

• Cross-sectional analysis of 84 pre-TKA patients using computer-assisted surgery (CAS).
• Pre-operative standing full-leg radiographs for CPAK classification.
• Real-time tracking of MCL and LCL elongation during passive knee motion via CAS.
• Linear mixed model analysis to assess alignment impact on ligament elongation.

Main Results:

• MCL length changes correlated significantly with aHKA during deep flexion; MCL shortened in valgus and lengthened in varus/neutral knees.
• CPAK III (valgus, high JLO) showed significantly more MCL shortening than other CPAK types at 90° flexion.
• LCL consistently loosened with flexion across all CPAK types; valgus knees had tighter LCL in extension.

Conclusions:

• Native MCL and LCL elongation patterns are dependent on knee alignment phenotypes.
• MCL behavior varies significantly with coronal alignment, unlike the LCL which consistently loosens with flexion.
• Findings support personalized TKA strategies that consider alignment-based ligament behavior for optimal kinematic replication.