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J Knee Surg 2024; 37(14): 959-965
DOI: 10.1055/a-2376-6999
Original Article

The Traditional Intramedullary Axis Underestimates the Medial Tibial Slope Compared to Transmalleolar Sagittal Axis in Image-based Robotic-Assisted Unicompartimental Knee Arthroplasty

Mattia Chirico 
1   Orthopaedic Clinic, University of Florence, Florence, Italy
,
Luigi Zanna
1   Orthopaedic Clinic, University of Florence, Florence, Italy
,
Mustafa Akkaya
1   Orthopaedic Clinic, University of Florence, Florence, Italy
,
Christian Carulli
1   Orthopaedic Clinic, University of Florence, Florence, Italy
,
Roberto Civinini
1   Orthopaedic Clinic, University of Florence, Florence, Italy
,
Matteo Innocenti
1   Orthopaedic Clinic, University of Florence, Florence, Italy
› Institutsangaben
Funding This research received no external funding.
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Abstract

The medial unicompartmental knee arthroplasty (mUKA) has been recognized as an excellent treatment for medial knee osteoarthritis. The posterior tibial slope (PTS) is measured radiographically with the intramedullary axis (IMA) to the tibial baseplate on the sagittal plane radiograph. However, in most computer-navigated or robotic mUKAs, the PTS is set from a transmalleolar axis (TMA).

The PTS difference was evaluatedbetween the sagittal TMA and the sagittal IMA of patients undergoing a CT-based primary robotic-assisted mUKA.

We retrospectively reviewed the preoperative computed tomography (CT) scans taken according to the MAKO system protocol (Stryker) of 67 patients undergoing mUKAs. We measured the angular difference between the IMA and the TMA in the sagittal plane.

Using the TMA to set the PTS the estimation of the slope of the medial tibial plateau would increase by an average of 1.9 ± 3.2 degreescompared to the IMA. Furthermore, in nineknees, PTS was decreased.

Tibial components implanted with the help of a CT scan-based preoperative planning MAKO will show an average of 1.9 degrees more than those measured on sagittal radiographs potentially of concern for knee kinematics. A universal language is needed to standardize the slope calculation and the respective reference axis used.

Keywords

mUKA - slope - knee - unicompartmental knee arthroplasty - robotic-assisted

Ethical Approval

The study was conducted in accordance with the Declaration of Helsinki and approved by the Institutional Review Board (or Ethics Committee) of “Azienda Ospedaliero Universitaria Careggi.”


Patient Consent

Informed consent was obtained from all subjects involved in the study. Written informed consent has been obtained from the patient(s) to publish this paper.


Authors' Contributions

Conceptualization, M.I. and M.C. Methodology, M.C. and M.I. Software, L.Z. Validation, M.A. Formal analysis, M.A. Investigation, M.A. Resources, M.I., C.C., and R.C. Data curation, M.I. and M.C. Writing—original draft preparation, M.C., M.I., and L.Z. Writing—review and editing, M.C., L.Z., and M.I. Visualization, M.A. Supervision, C.C. and R.C. Project administration, M.I. and R.C. All authors have read and agreed to the published version of the manuscript.


Data Availability

Suggested data availability statements are available in the section, “MDPI Research Data Policies,” at https://www.mdpi.com/ethics.




Publikationsverlauf

Eingereicht: 02. Januar 2024

Angenommen: 30. Juli 2024

Accepted Manuscript online:
31. Juli 2024

Artikel online veröffentlicht:
16. August 2024

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