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Published on: March 1, 2024
Clinical outcomes and biomechanics in bicruciate-retaining total knee arthroplasty
Kenichi Kono1, Tomofumi Kage1, Takaharu Yamazaki2
1Department of Orthopaedic Surgery, Faculty of Medicine The University of Tokyo Tokyo Japan.
Purpose:
To clarify the influence of biomechanics on post-operative clinical outcomes in bicruciate-retaining total knee arthroplasty (BCR-TKA).
Methods:
Severe medial osteoarthritis who underwent BCR-TKA were examined. Each patient was asked to perform a squat (weight-bearing [WB]) and active assisted knee flexion (non-WB [NWB]) under single fluoroscopy surveillance. A 2D-to-3D registration technique was used. Patients were divided into two groups based on their 1-year post-operative patient-reported outcome measures (PROMs) using hierarchical cluster analysis. The rotational alignment on computed tomography, anterior stability at 30° of knee flexion, axial rotation of the femur relative to the tibial component and anteroposterior translation of the medial and lateral femorotibial contact points were measured.
Results:
Components did not significantly differ between the groups, with 1.6 ± 5.0° and 5.4 ± 4.7° of femoral internal rotation in the low PROM (N = 28) and high PROM (N = 8) groups, respectively. Moreover, anterior stability did not significantly differ (low PROM: 4.9 ± 1.4 mm, high PROM: 5.3 ± 1.0 mm). The knee externally rotated from 0° to 70° and from 50° to 110° of flexion during WB and NWB, respectively. The low-PROM group exhibited more external rotation across all ranges of motion. Medial contact points moved backwards from 0° to 30° of flexion during WB, forward from 30° to 100° of flexion, and backwards from 100° to 110° of flexion. The low-PROM group was positioned more forward throughout the full range of motion during WB. Lateral contact points moved backwards at 0-30° of flexion, forward at 70-100° of flexion, and backwards at 100-110° of flexion during WB, while there was backward movement at 50° of flexion during NWB. Both activities exhibited a more posterior position in the low-PROM group throughout the full range of motion.
Conclusion:
The femoral component in the low-PROM group was externally rotated across all ranges of motion, and the lateral contact points were posteriorly located in BCR-TKA.
Level Of Evidence:
Level II, prospective cohort study.
