Medial condylar wall is a reliable landmark to kinematically
Kinematic alignment (KA) aligns the femoral implant perpendicular to the cylindrical axis in the frontal and axial plane. This study aims to assess if the orientation of condylar walls may be suitable for use as an anatomical landmark to kinematically align the femoral component in medial UKA.

73 patients undergoing medial UKA had pre-operative CT imaging to generate 3D models. 28 patients were included in the study. The ideal KA was determined using the cylindrical axis in the frontal and axial plane. Simulations using the medial wall of the medial condyle (MWMC) and the lateral wall of the medial condyle (LWMC) were performed to set the frontal alignment. To set the axial alignment, the MWMC, LWMC, medial wall of the lateral condyle (MWLC), and medial diagonal line (MDL) anatomical landmarks were investigated.

Results:
--Use of the MWMC let to similar frontal alignment compared to the ideal KA (2.9° valgus vs 3.4° valgus) with 46.4% of measurements being less than 1.0° different from the ideal KA and only 1 simulation with greater than 4.0° difference.

--Use of the MWMC led to very similar axial alignments compared to the ideal KA with 75.0% of measurements being less than 1.0degrees different from the ideal KA, and a maximum difference of 3.0°.

--Use of the MWLC and MDL was associated with significant statistical differences when compared to the ideal KA.

The original orientation of the medial condylar wall appears to be a good anatomical reference for aligning the femoral component in medial KA UKA in both the axial and frontal planes. Other evaluated landmarks were found to be unreliable.

Source: https://link.springer.com/article/10.1007/s00167-021-06683-9
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