Table 1.

Definition of the MRI findings assessed

MRI finding	Definition
Meniscal degeneration	Significant hyperintense signal change within the meniscus without contact to the surface.
Meniscal tear	Significant linear hyperintense signal change within the meniscus with contact to the surface.
Cartilage lesion	Focal substance loss of the cartilage ICRS first to ICRS fourth degree.
ACL and PCL abnormalities	Tears, partial tears and significant signal alterations of the ACL or the PCL as well as the presence of a graft after ligament reconstruction.
Abnormalities of the patellar tendon or the quadriceps tendon (overall and subclassified with respect to location)	Morphological changes of the insertion or the tendon itself (hyperintense signal change, tendon thickening, oedema and ossicles).
Trochlear dysplasia	Flattened trochlear groove (Dejour type A–D).
Bone marrow oedema of the femoral condyles	Significant hyperintense signal change within the bone of the medial or lateral femoral condyle close to the articular surface.
Distal femoral cortical irregularities	Circumscript area of signal hyperintensity with a dark rim at the periphery at the insertion sites of the medial or lateral head of the gastrocnemius or the adductor magnus at the distal femur.
FOPE zones	Focal bone marrow oedema (significant hyperintense signal change) adjacent to areas of physeal fusion.
Joint effusion	Presence of increased intra-articular fluid.
Baker’s cyst	Popliteal fluid collection between medial head of the M. gastrocnemius and M. semimembranosus.
Hoffa’s fat pad oedema	Significant hyperintense signal change in the Hoffa’s fat pad.

ACL, anterior cruciate ligament; FOPE, focal periphyseal oedema; ICRS, International Cartilage Repair Society; PCL, posterior cruciate ligament.