Unrestricted Kinematic Alignment Is a Feasible Strategy for Lateral Compartment Osteoarthritis: Short-Term Outcomes...

Area of Science:

• Orthopedic Surgery
• Biomechanics
• Arthroplasty

Background:

• Unrestricted kinematic alignment (uKA) is increasingly used in total knee arthroplasty (TKA).
• Concerns exist regarding its application in lateral compartment osteoarthritis (OA) due to potential gap imbalance and alignment outliers.
• The contralateral non-OA knee-referenced, caliper-verified uKA approach offers a potential solution.

Purpose of the Study:

• To evaluate surgical, radiographic, and clinical outcomes of contralateral non-OA knee-referenced, caliper-verified uKA in patients with lateral compartment OA.
• To assess the feasibility and effectiveness of this specific uKA technique in a challenging patient subgroup.

Main Methods:

• Retrospective study of 40 patients with isolated lateral compartment OA undergoing primary TKA.
• Utilized contralateral non-OA knee-referenced, caliper-verified uKA.
• Assessed surgical (bone resection, gap balance), radiographic (alignment angles, CPAK), and patient-reported outcomes (PROs) at minimum 2-year follow-up.

Main Results:

• Medial osteochondral resection was consistently greater than lateral.
• 95% of knees achieved gap balance ≤ 2 mm in extension.
• Approximately 90% of cases restored to the same Coronal Plane Alignment of the Knee (CPAK) category postoperatively.
• All PROs significantly improved, comparable to the contralateral knee.

Conclusions:

• Caliper-verified uKA, guided by the contralateral non-OA knee, is applicable for lateral compartment OA.
• This strategy ensures stable soft-tissue balance and reliable coronal alignment restoration.
• Favorable clinical outcomes are achievable in carefully selected valgus knees undergoing TKA with this method.