Table 2 Comparison between preoperative MRI bone oedema score* and description of histopathology for resected bone specimens
Patient no.Bone specimenMRI bone oedema scoreHistopathology report
Reader 1Reader 2
6Left 1st metatarsal head, medial eminence66Moderately intense patchy lymphoplasmacytic infiltration in the subchondral marrow, patchy pannus formation over the articular cartilage and subchondral cyst
7Right 5th metatarsal head22Thinning and focal necrosis of articular cartilage with marginal pannus formation with patchy aggregations of mature small lymphocytes in the subchondral region, plus subchondral cyst
10Left 2nd metacarpal head00Degeneration and focal loss of cartilage and thin fibrovascular pannus formation, focal remodelling of subchondral bone with light mononuclear cell infiltration and slight marrow fibrosis
Left 3rd metacarpal head00Patchy loss of articular cartilage with thin fibrous pannus formation, irregular interface between articular cartilage and subchondral bone with prominent congested capillaries but no evidence of osteitis
Left 4th metacarpal head00Degeneration of articular cartilage with thin fibrous pannus formation at joint margin, slight osteitis
Left 5th metacarpal head00Degeneration of articular cartilage, thin fibrous pannus formation with slight focal osteitis and some remodelling of subchondral bone
11Left 1st metatarsal head12Focal disruption of the articular cartilage and a flask-shaped defect extending into the medullary space; the lining is composed of fibrous granulation tissue with telangiectatic new blood vessels and slight lymphocyte infiltration; elsewhere the normal articular cartilage is replaced by fibrous pannus and fibrocartilage
  • *MRI bone oedema scored separately by 2 radiologists according to the extent and intensity of bone oedema at the site where bone was resected as follows: spatial extent of bone oedema; Grade 0 for none, Grade 1 for ⩽33%, Grade 2 for 34–66%, Grade 3 for 67–100% of area of bony site assessed. Intensity of bone oedema; Grade 0 = none, Grade 1 = moderate intensity, Grade 2 = high intensity. Total score comprises spatial extent×intensity scores. Maximum possible score per site = 6.