Table 1.

Variables generated by Croft scoring and the OARSI atlas, with additional derived variables

Variable	Grading	Variable used in the analysis
Osteoarthritis (Croft score)	0–5	Progressive OA: Croft score > 3 at baseline and an increase in score at follow-up Incident OA: Croft score < 3 at baseline and > 3 at follow-up
Osteophytes		Change in osteophyte score: sum of all semi-quantitative osteophyte grades at follow-up minus their sum at baseline
Superior femoral	0–3
inferior femoral	0–3
Superior acetabular	0–3
inferior acetabular	0, 1
JSN		Change in JSN score: sum of both superior and medial semi-quantitative JSN grades at follow-up minus this sum at baseline
Superior	0–3
Medial	0–3

Abbreviations: OARSI Osteoarthritis Research Society International, JSN joint space narrowing, mJSW medial minimal joint space width