Table 1

Criteria for MRI-defined OA derived from MOAKS ratings

MRI-defined tibiofemoral OAMeets either of the following criteria in either medial or lateral tibiofemoral compartment:

  • A definite osteophyte* AND full-thickness cartilage loss† or

  • A definite osteophyte* OR full-thickness cartilage loss PLUS two of the following:

    • subchondral BML‡ not associated with meniscal or ligamentous attachments

    • meniscal subluxation, maceration or degeneration§

    • partial-thickness cartilage loss where full-thickness loss is absent¶

Mixed MRI-defined tibiofemoral OAMeets the above criteria by having some OA features in one tibiofemoral compartment and others in a second tibiofemoral compartment
MRI-defined patellofemoral OAA definite osteophyte* and partial or full-thickness cartilage loss in the patellofemoral compartment

  • ∗A score of ≥1 on the osteophyte MOAKS subscale for a specific compartment.

  • †A score of ≥1 of the cartilage MOAKS subscale for a specific compartment.

  • ‡A score of ≥1 on the BML MOAKS subscale for a specific compartment.

  • §A score of ≥1 on the meniscal MOAKS subscale.

  • ¶A score of 0 on the cartilage MOAKS subscale and a score of ≥1 on the BML MOAKS subscale for a specific compartment.

  • BML, bone marrow lesion; MOAKS, MRI Osteoarthritis Knee Score; OA, osteoarthritis.