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J Knee Surg 2022; 35(07): 757-766
DOI: 10.1055/s-0040-1718598
Original Article

Low-Degree Tibial Slope Angle Prevents Component Overhang by Enlarging the Lateral Plateau Surface Area in Total Knee Arthroplasty

Mehmet Emin Simsek
1   Department of Orthopedics and Traumatology, Lokman Hekim University, Ankara, Turkey
,
Mustafa Akkaya
2   Department of Orthopedics and Traumatology, Yildirim Beyazit University, Yenimahalle Training and Research Hospital, Ankara, Turkey
,
Safa Gursoy
2   Department of Orthopedics and Traumatology, Yildirim Beyazit University, Yenimahalle Training and Research Hospital, Ankara, Turkey
,
Özgür Kaya
3   Department of Orthopedics and Traumatology, Private Lokman Hekim Hospital, Ankara, Turkey
,
Murat Bozkurt
4   Department of Orthopedics and Traumatology, Yildirim Beyazit University, Ankara, Turkey
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Abstract

This study aimed to investigate whether overhang or underhang around the tibial component that occurs during the placement of tibial baseplates was affected by different slope angles of the tibial plateau and determine the changes in the lateral and medial plateau diameters while changing the slope angle in total knee arthroplasty. Three-dimensional tibia models were reconstructed using the computed tomography scans of 120 tibial dry bones. Tibial plateau slope cuts were performed with 9, 7, 5, 3, and 0 degrees of slope angles 2-mm below the subchondral bone in the deepest point of the medial plateau. Total, lateral, and medial tibial plateau areas and overhang/underhang rates were measured at each cut level. Digital implantations of the asymmetric and symmetric tibial baseplates were made on the tibial plateau with each slope angles. Following the implantations, the slope angle that prevents overhang or underhang at the bone border and the slope angle that has more surface area was identified. A significant increase was noted in the total tibial surface area, lateral plateau surface area, and lateral anteroposterior distance, whereas the slope cut angles were changed from 9 to 0 degrees in both gender groups. It was found that the amount of posteromedial underhang and posterolateral overhang increased in both the asymmetric and symmetric tibial baseplates when the slope angle was changed from 0 to 9 degrees. Although the mediolateral diameter did not change after the proximal tibia cuts at different slope angles, the surface area and anteroposterior diameter of the lateral plateau could change, leading to increased lateral plateau area. Although prosthesis designs are highly compatible with the tibial surface area, it should be noted that the component overhangs, especially beyond the posterolateral edge, it can be prevented by changing the slope cut angle in males and females.

Keywords

total knee arthroplasty - tibial baseplate - overhang - tibia plateau area

Ethical Approval

All procedures performed in studies involving human participants were in accordance with the ethical standards of the institutional and/or national research committee and with the 1964 Helsinki declaration and its later amendments or comparable ethical standards. Informed consent was obtained from all individual participants included in the study.




Publication History

Received: 12 February 2020

Accepted: 25 August 2020

Article published online:
27 October 2020

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