Conference Contribution Details
Mandatory Fields
Hyslop, E., Woodburn, J., McInnes, I.B., Semple, R., Newcombe, L., Hendry, G., Rafferty, D., De Mits, S., Turner, D.E.
European League Against Rheumatism Conference (EULAR)
Forefoot pain in psoriatic arthritis can be predicted by inflammatory and mechanical factors - EULAR11-3061
Poster Presentation
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Background: Forefoot pain and deformity are common in psoriatic arthritis (PsA) patients [1]. Inflammatory and mechanical factors have been shown to be important independent predictors of foot impairment in RA [2]. The same mechanisms may be important in PsA but have not been investigated. Objectives: To identify independent predictors of forefoot pain at the MTP joint in patients with PsA. Methods: Twenty nine PsA patients (10 male, 19 female) with a mean ±SD age of 47.6 ±12.3 years and disease duration 11.3 ±9.7 years were recruited from rheumatology outpatient clinics at Glasgow Royal Infirmary. An experienced rheumatology podiatrist undertook all the foot assessments. MTP joint pain and swelling was determined from direct firm palpation. Clinical examination detected the presence/absence of toe deformity and MTP joint subluxation. 145 MTP joints were assessed using B-Mode and power Doppler ultrasound (Esaote MyLab70, 10-18MHz,using a linear array probe) to detect the presence/absence of synovitis, effusion and joint erosion by a single blinded podiatrist trained in musculoskeletal ultrasound. Barefoot peak pressures (kPa) across the forefoot were measured using a plantar pressure measurement system (Emed-ST, Novel GmbH, Munich, Germany). The presence/absence of clinical features were summarised as proportions and peak pressure as mean ±SD. Binary logistic regression analysis was used to evaluate the independence of the association between selected inflammatory and mechanical factors and MTP pain in PsA. Results: 98/145 (67.6%) of MTP joints were painful. 107/145 (73.8%) MTP joints were deformed; 83/145 (57.2%) were subluxed; and 2/145 (1.4%) were clinically swollen. Ultrasound detected synovitis in 18/145 (12.4%); Erosion in 19/145 (13.1%); and effusion in 63/145 (43.4%) of MTP joints. The mean ±SD peak pressure for MTP1 was 308.9kPa ±190.1, MTP2- 559.9kPa ±286.9, MTP3- 489.2kPa ±208.4, MTP4- 297.9kPa ±, and MTP5- 274.9kPa ±177.1. Using binary logistic regression the presence of ultrasound confirmed synovitis (odds ratio (OR) = 4.04; 95%CI 1.31, 12.45; p=0.015) and elevated peak pressures (OR=1.002, 95% CI 1.000, 1.004; p=0.02) were independent predictors for MTP pain in PsA. The sensitivity and specificity of the model were 21.3% and 79.7% respectively. The positive and negative predictive value was 62.5% and 71.3%. Conclusions: MTP pain in PsA can be predicted by inflammatory and mechanical factors. Both should be targeted in the treatment of forefoot pain.
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