Coronal alignment in total knee replacement: historical review, contemporary analysis, and future direction

Area of Science:

• Orthopedic surgery
• Biomechanical engineering
• Medical device technology

Background:

• Computer navigation and patient-specific instrumentation are widely used in total knee replacement (TKR).
• These systems aim to achieve neutral mechanical alignment, historically considered crucial for TKR success.
• Recent evidence questions the necessity of perfect alignment, showing no significant difference in survivorship between well-aligned and malaligned TKRs.

Purpose of the Study:

• To review the anatomical alignment principles of the knee.
• To examine historical and current data supporting the neutral mechanical axis in TKR.
• To assess the feasibility of kinematically-aligned TKR approaches.

Main Methods:

• Literature review of anatomical knee alignment.
• Analysis of historical and contemporary data on TKR alignment.
• Evaluation of kinematic alignment techniques in TKR.

Main Results:

• The review of existing literature indicates that achieving neutral mechanical alignment is still considered optimal for TKR.
• While advanced technologies improve alignment accuracy, their impact on long-term outcomes requires further investigation.
• Kinematic alignment presents a potential alternative but needs more supporting data.

Conclusions:

• The neutral mechanical axis continues to be the preferred alignment strategy in total knee replacement.
• Further research is needed to definitively establish the long-term benefits of kinematic alignment versus traditional mechanical alignment.
• Optimizing TKR outcomes relies on a thorough understanding of knee biomechanics and alignment principles.