Table 1.

Main studies addressing the histopathologic picture of subchondral bone marrow involvement in rheumatoid arthritis

	Number of samples	Disease duration*	Site of surgery	MRI	Main findings
Jimenez-Boj et al. [39]	12 (12 pts)	18.9 (± 2.8)	10 small joints, 1 wrist, 1 large joint	-	Lymphocytic aggregates with predominance of B cells (immunohistochemistry)
Bugatti et al. [38]	8 (8 pts)	12.5 (± 8.8)	2 small joints, 1 wrist, 5 large joints	-	Lymphocytic aggregates (immunohistochemistry)
Kuca-Warnawin et al. [23]	6 (6 pts)	-	6 large joints	-	Lymphocytic aggregates (immunohistochemistry)
Jimenez-Boj et al. [35]	12 (3 pts)	15.3 (± 8.1)	12 small joints	Available	Infiltration of hematopoietic cells, lymphocytic aggregates, blood vessels (histology)
McQueen et al. [36]	7(4 pts)	27 (± 11.7)	7 small joints	Available	Lymphoplasmacytic infiltration, focal necrosis, fibrosis (histology)
Dalbeth et al. [37]	28 (11 pts)	21 (± 9.6)	23 small joints, 2 wrists, 3 ankles	Available	Infiltration of macrophages, plasma cells, CD8+ T cells, B cells (immunohistochemistry)
Total	73 (44 pts)		54 small joints (hands/feet), 7 wrists/ankles, 12 large joints (knee/hip)

*Data given as mean (± SD) years. Pts, patients.