Kinematical alignment better restores native patellar tracking pattern than mechanical alignment.

Area of Science:

• Orthopedic surgery
• Biomechanical analysis
• Arthroplasty research

Background:

• Restoring natural knee function after total knee arthroplasty (TKA) is crucial for patient outcomes.
• Patellar tracking, the motion of the kneecap during flexion, significantly impacts TKA success.
• Understanding alignment techniques' effects on patellar mechanics is vital for surgical innovation.

Purpose of the Study:

• To compare the effectiveness of kinematic alignment (KA) versus mechanical alignment (MA) in restoring native patellar tracking patterns.
• To utilize a clustering algorithm to objectively analyze and differentiate patellar tracking behaviors.

Main Methods:

• Twenty cadavers (40 knees) underwent TKA, with one knee randomly assigned to KA and the other to MA.
• KA TKA used a caliper-verified technique; MA TKA used a measured resection technique.
• Patellar tracking was measured using motion analysis, and data were clustered using a density-based algorithm.

Main Results:

• Kinematic alignment (KA) demonstrated significantly different patellar tracking patterns compared to mechanical alignment (MA).
• A higher proportion of KA knees exhibited post-TKA patellar tracking patterns within the pre-TKA dominant cluster.
• KA more closely replicated native knee patellar tracking patterns than MA (p < 0.05).

Conclusions:

• Kinematic alignment (KA) is superior to mechanical alignment (MA) in restoring natural patellar tracking post-total knee arthroplasty.
• This study provides biomechanical evidence supporting KA for improved patellar mechanics in TKA.