Table 3

 Radiological features of the patient groups

Polyarticular PsA n = 388, n (%)Polyarticular RA n = 366, n (%)Non-polyarticular PsA n = 200, n (%)Test statistic for all three groupsp ValueTest statistic for polyarticular PsAv non-polyarticular PsAp Value
NS, not significant; PsA, psoriatic arthritis; RA, rheumatoid arthritis.
*Marginal and non-marginal syndesmophytes in any spinal segment.
†Entheseal erosion and new bone formation at the inferior and posterior aspects of calcaneum, tibial and patellar sites and pelvis.
‡Osteolysis and ankylosis at any of the small joints of hands and feet.
§Ray involvement indicates the combined involvement of metacarpophalangeal, proximal interphalangeal and distal interphalangeal joint of same digit.
Marginal syndoesmophytes*5 (1)1 (<1)16 (8)χ2 = 41.5<0.001χ2 = 21.70<0.001
Non-marginal syndesmophytes*25 (6)16 (4)22 (11)χ2 = 13.10.01χ2 = 7.730.021
Entheseal erosion†23 (6)21 (6)10 (5)χ2 = 2.48NSχ2 = 1.02NS
Entheseal new bone formation†49 (13)35 (10)29 (15)χ2 = 5.23NSχ2 = 1.11NS
Distal interphalangeal erosion82 (21)40 (11)40 (20)χ2 = 16.400.003χ2 = 1.38NS
Juxta-articular new bone59 (15)15 (4)37 (19)χ2 = 35.52<0.001χ2 = 2.91NS
Osteolysis‡42 (11)34 (9)23 (12)χ2 = 2.40NSχ2 = 1.54NS
Tuft osteolysis14 (4)08 (4)χ2 = 15.690.003χ2 = 1.48NS
Ankylosis‡38 (10)11 (3)23 (12)χ2 = 19.490.001χ2 = 2.02NS
Ray involvement§18 (5)6 (2)13 (7)χ2 = 10.900.028χ2 = 1.99NS