[Limits of kinematic alignment and recommendations for its safe application]

Area of Science:

• Orthopedic Surgery
• Biomechanical Engineering

Background:

• Kinematic alignment (KA) in total knee arthroplasty (TKA) is gaining traction, but surgeon adoption is limited by safety and universality concerns.
• Comparative studies show variable outcomes for KA, with significant benefits observed only in studies with strict patient indications.

Purpose of the Study:

• To review current evidence and theoretical considerations for ideal and non-ideal patient selection in KA.
• To provide recommendations for the safe application of KA based on clinical experience.

Main Methods:

• Literature review of existing studies on kinematic alignment in TKA.
• Analysis of theoretical considerations for patient selection.
• Synthesis of clinical experience and
• lessons learned
• for KA.

Main Results:

• Primary varus osteoarthritis is a favorable indication for KA.
• Extra-articular deformities and collateral ligament instability are contraindications or limitations for KA.
• Valgus deformities, especially with associated hip/ankle pathologies, present higher risks for KA, suggesting a restricted approach.

Conclusions:

• Careful patient selection is crucial for successful kinematic alignment in TKA.
• Weight-bearing long-leg X-rays, stress radiography, and 3D imaging (CT/MRI) aid in assessing suitability and planning component positioning.
• A restricted KA approach, balancing individualized positioning with overall limb alignment, may be beneficial for complex valgus cases.