Table 2.

Anatomic distribution of peripheral arthritis and enthesitis.

Years (y) recruited	<1982	1980–1985	2002–2003	2000–2006	1995–2010	1989–2012	2008–2015	2015–2016
Country	Canada	Mexico	Germany	Italy	Taiwan	USA	France	India
Cohort size	39	110	118	59	195	234	114	55
Y f/u	1.9	12.2	4	3	>1.5	–b	2.5	<5
SpA # (%)	All SEA	35(32) JoAS	All SpA mNY or ESSG	All ERA	73(37) ERA	All ERA	All SpA	All ERA
Peripheral arthritis
% Knee	83	100	77	65	52	46	58	–
% Ankle	–	80	40	48	38	36	38	27
% Hip	–	83	38	–	43	19	46	–
% Mid-foot	–	89	9.3	58	–	–	9	36 by ultrasound 54 by MRI
% Fingers	–	23	25	–	18a	–	12	–
% Toes or MTP	–	86	27	–	16a	–	17	4 toes 16 MTP
% Wrist	–	14	–	–	16	20	25	–
% Dactylitis	–	–	13	–	–	–	13	7.3 (toes)
Enthesitis			–		–
% Achilles	51	34		28		33	74c	44
% Plantar front insertion	–	–		–		–	39	20d See note
% Plantar calcaneal insertion	67	54		38		–	See notec	See noted
% Knee	49	23		–		44	46	–
% Pelvis	5	9		–		30	22c	–
% Greater trochanter	–	14		–		–	See Notec	–
References	(18)	(39)	(17)	(24)	(25)	(26)	(16)	(40)

Cohorts are listed across the top by years of recruitment and nationality. ERA, enthesitis related arthritis; ESSG, European Spondyloarthropathy Study Group; mNY, modified New York criteria for ankylosing spondylitis (28). ASAS, Assessment of Spondyloarthritis International Society; F/u, median or mean follow up, depending upon the study; MTP, metatarsal-phalangeal joints. No data or insufficient data (<1%) designated as –. Knee includes tibial tuberosity, infrapatellar, and suprapatellar sites. Pelvis includes ischial tuberosity, iliac crest, and interosseous ligaments of sacroiliac joint.

^aSpecified as “small joints” of fingers or feet.

^bCross sectional inception cohort without specified follow up.

^c74% had Achilles or plantar calcaneal insertion enthesitis. “Pelvis” was lumped with greater trochanteric enthesitis in this study.

^dNot specified if frontal or calcaneal plantar fasciitis.