Radiographic Grading

Tibial Femoral Compartmental Grading is Evaluated on a standing AP or semi-flexed PA view.

Alignment is measured as the angle between the Femur and Tibia Anatomical axes. This angle is not as accurate as the Hip-Knee-Ankle (HKA) angle, but, by adding 5 degrees, gives a good approximation of HKA and whether a patient is in varus (-) or valgus (+).

Medial/Lateral identifies the more damaged compartment which is graded.

Joint Space (JS) measures the gap between the femur and tibia, giving an indication to the amount of cartilage loss in the knee. Scores range from 0 normal to 3 complete loss.

Femoral Osteophytes (FO) evaluates new bone growth on the femur. As OA progresses, a patients knee will compensate with new bone growth. Osteophytes can lead to restricted movement and increased pain. Scores range from 0 no osteophytes to 3 bulky extensive osteophytes.

Tibial Erosion (TE) observes the wearing away of bone from the tibial plateau. Erosion occurs when there is no remaining cartilage separating the bones. Scores range from 0, no erosion to 4, major tibial bone loss.

Subluxation (SU) inspects the off-set distance between the femur and tibia mid-points. Scores range from 0, no mis-alignment to 3, severe displacement.

Total Score is the sum of the JS, FO, TE and SU. Grading severity may range from 0, no radiographic OA, to 13 a very severely damaged knee.


For more specifics please see Item three under Grading the Joint


Patello-Femoral Compartment: Evaluated on axial ‘Sky-line’ view

Medial/Lateral/Neutral describes the patella alignment in the femoral sulcus and if there is any relative deviation from the midline (neutral)

Joint Space measures the distance between the patella and femur. As cartilage loss progresses, the joint space will diminish. Scores range from 0-3.

Femoral Osteophytes examines new bone growth on the femur. As OA progresses, a patients knee will compensate with new bone growth. Scores range from 0-3.

Patella Erosion observes the erosion of bone from the patella. Erosion can only occur when there is no joint space left in the knee and the patella is in direct contact with the femur. Scores range from 0-3.

Subluxation estimates the off-set between the patella midline and the femur sulcus. Scores range from 0-3.

Total Score is the sum of these grades: 0, no OA to 10, extreme PF joint damage.