Modification of Kellgren and Lawrence grades used in this study
| Grade | Abnormalities | Criteria |
| 0 | Normal | |
| 1 | OSP | Minor osteophytes |
| 2 | JSN +OSP | |
| 3 | JSN, OSP, SSC, CYST | JSN + 2 others |
| 4 | JSN, OSP, SSC, CYST | JSN + 3 others |
| 5 | JSN, OSP, SSC, CYST, FD | As grade 4 + FD |
OSP=osteophytes, JSN=joint space narrowing, SSC=sub-chondral sclerosis, CYST=sub-chondral cyst formation, FD=femoral head deformity.