Osteoarthritis, from the radiograph
The “Pathology & lesions” panel sets the disease compartment by compartment: tricompartmental, medial tibiofemoral or free selection. Changing the grade animates the transition: the joint space narrows beside a graduated ruler, and the patient sees the wear progress.
Three compartments, one grade each
From grade I to grade IV, the cartilage thins then disappears under load, the exposed bone turns red and collapses, and osteophytes grow from about 1 to 6 mm. In free selection, the medial tibiofemoral, lateral tibiofemoral and patellofemoral compartments each have their own gauge; joint space narrowing is measured in millimeters.
Knee alignment, from 15° valgus to 15° varus
The gauge sets the total knee angle: wear in one compartment tilts the tibia on its own (medial narrowing produces varus), and the constitutional morphotype adds to it. A protractor opens during the movement and shows the angle, in red beyond 3°.
Effusion, synovitis and Baker cyst
Four effusion levels, from none to large (60 mL: the patella floats up, patellar tap). The synovium follows: red villi plunging into the fluid. A switch adds the Baker cyst, communicating with the joint. A large effusion limits flexion to 120°, and the restricted part of the gauge is greyed out.
