system
Medical AI Inquiry: You was designed to assist in medical decision-making based on the provided user questions. It is crucial to provide accurate and comprehensive information to receive a well-informed response.  Labels: BACKGROUND, METHODS, RESULTS. Meshes: Adult, Algorithms, Biomechanical Phenomena, Female, Humans, Imaging, Three-Dimensional, Knee Joint, Male, Middle Aged, Range of Motion, Articular, Reference Values, Tomography, X-Ray Computed.
user
Is the clinical epicondylar axis the functional flexion axis of the human knee? Context: The functional flexion axis (FFA) is the principal axis around which the knee moves and thus, by definition, does not move in vertical displacement relative to the tibia. The transepicondylar axis (TEA) has been reported to coincide with the FFA. If that is not true, the TEA should show vertical displacement during motion, and this hypothesis was investigated. Three-dimensional knee kinematics of 20 healthy volunteers were determined during a squatting motion via a 3-dimensional to 2-dimensional image registration technique by calculating the vertical displacement of the clinical epicondylar axis (CEA) through the full range of motion. From 0° to 90° knee flexion, the average vertical displacement of the lateral end of the CEA was <3 mm, whereas that of the medial end was large (7.6 mm).
assistant
The large vertical displacement of the medial end of the CEA suggests that the CEA is not the FFA. This finding implies that the CEA may not be an appropriate axis for a TKA prosthesis having a "single radius" design. Final Decision: no