Functional Alignment Total Knee Arthroplasty Using the 5C® MEDic Medial Pivot Knee System
Vasileios Kosmas1*, Chagigia Mousa1, Georgios Papadimitriou1, Iason Papaskarlatos1, Vasileios Sakellariou1
1Orthopedic Clinic OSTEON, Athens Medical Center, Athens, Greece.
*Corresponding Author: Vasileios Kosmas, MD, Orthopedic Clinic OSTEON, Athens Medical Center, 5–7 Distomou Street, Marousi, Athens 15125, Greece.
https://doi.org/10.58624/SVOAOR.2026.06.022
Received: July 27, 2026
Published: August 13, 2026
Citation: Kosmas V, Mousa C, Papadimitriou G, Papaskarlatos I, Sakellariou V. Functional Alignment Total Knee Arthroplasty Using the 5C® MEDic Medial Pivot Knee System. SVOA Orthopaedics 2026, 6:4, 151-164. doi: 10.58624/SVOAOR.2026.06.022
Abstract
Background: Despite the excellent survivorship of modern total knee arthroplasty (TKA), up to one in five patients remains dissatisfied following surgery, often because the reconstructed knee fails to reproduce physiological kinematics and soft-tissue behaviour. Functional alignment has emerged as a patient-specific alignment philosophy that aims to restore constitutional anatomy while minimizing ligament releases [6–13]. When combined with a medial pivot implant, this approach seeks to reproduce native knee biomechanics and improve functional recovery.
Technique: This Technical Note describes the standardized surgical technique using the 5C® MEDic Medial Pivot Knee System. Preoperative planning is based on constitutional alignment analysis using long-leg radiographs, arithmetic hip–knee–ankle angle (aHKA), lateral distal femoral angle (LDFA), medial proximal tibial angle (MPTA), joint-line obliquity (JLO), and CPAK classification. A computer-navigated medial parapatellar approach is employed without robotic assistance or patient-specific instrumentation. Bone resections and implant positioning are individualized using computer-assisted navigation to restore physiological alignment while preserving native ligament balance.
Clinical Experience: The described technique has been applied in a consecutive series of 419 primary total knee arthroplasties. Early clinical assessment demonstrated substantial improvement in patient-reported outcome measures, restoration of knee motion, low complication rates, and excellent short-term implant survivorship.
Conclusions: Functional alignment using the 5C® MEDic Medial Pivot Knee System represents a reproducible patient-specific technique that combines individualized alignment with implant characteristics designed to reproduce native knee kinematics. Early clinical experience supports the safety and reproducibility of this surgical strategy, although longer-term comparative studies remain necessary.
Keywords: Functional alignment, Total knee arthroplasty, Medial pivot, CPAK, 5C® MEDic