← Part 1 · Native surfacesPART 2 / CARTILAGE LOSS

See what has worn away.

Native knee · extension

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Added joint-line varus 0°

Wear & alignment

Medial compartment

Femoral flexion

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Original surface position

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These four visual teaching grades follow the descriptions supplied for this demonstration; they are not a validated clinical grading system. Cartilage loss is illustrated in one compartment. Joint-line varus is an illustrative change from the saved anatomy: the medial femoral condyle lengthens and the tibia inclines to match, while the proximal femur remains unchanged. The angle is added tilt, not a measured anatomical angle. Varus/valgus adds an illustrative 3° angulation at the joint; the tibia and fibula move rigidly relative to the femur. Bone erosion and dynamic joint motion are not modeled. Patella, menisci and cruciate ligaments are omitted.

Adapted from Open Knee(s), oks009 · CC BY-SA 3.0 and model attribution