Tibiofemoral contact points relative to flexion angle measured with MRI.
OBJECTIVE
To determine whether knee flexion influenced bony contact movements during flexion.


METHODS
Accurate three-dimensional (3D) measurements of tibiofemoral bony contact points in vivo was performed using magnetic resonance imaging technology at 0 degrees, 30 degrees and 60 degrees of flexion.


BACKGROUND
Magnetic resonance imaging is an accurate non-invasive tool for visualizing muscles, tendons, and bone, and provides precise 3D co-ordinates.


METHODS
Magnetic resonance imaging recordings were made from the right knee of 16 subjects with no history of knee dysfunction at 0 degrees, 30 degrees and 60 degrees of flexion. Joint contact movements were reported as changes of the contact point's position on the medial and lateral tibial condyle with respect to a fixed reference point for each flexion angle.


RESULTS
The dominant motion of the centroid of the contact area was posterior with a concomitant inferior and lateral displacement when flexing from 0-30 degrees. Increased flexion to 60 degrees the contact points moved slightly anterior, superior and continued laterally. Comparing movements between the medial and lateral compartments, larger displacement magnitudes were observed laterally. Additionally, tibial rotations of 3-5 degrees were noted relative to the femur.


CONCLUSIONS
Based on magnetic resonance imaging co-ordinates and the rotated anatomical reference frame, the geometric equations to derive the contact point between the tibiofemoral articulating surfaces is a viable means to investigate tibiofemoral bony contact movement.


CONCLUSIONS
Contact areas and pressure distributions have been reported using cadaveric specimens but interpretation of the results is limited. Other investigations have been restricted to sagittal plane movement. Using kinematic magnetic resonance imaging, accurate non-invasive 3D recordings of the normal knee at increments of flexion are possible. The normative baseline date can be compared against that of the pathological knee, such as cruciate ligament injury or the status of post-operative meniscectomy in order to examine skeletal joint motion and stability.
Wretenberg
Per
P
Department of Orthopaedic Surgery, Karolinska Hospital, S-171 76 Stockholm, Sweden.
Ramsey
Dan K
DK
Németh
Gunnar
G
D000328:Adult; D001696:Biomechanical Phenomena; D005260:Female; D005269:Femur / Q000502:physiology*; D006801:Humans; D021621:Imaging, Three-Dimensional; D007719:Knee Joint / Q000502:physiology*; D008279:Magnetic Resonance Imaging; D008297:Male; D013977:Tibia / Q000502:physiology*