Plantar forefoot pressures in psoriatic arthritis-related dactylitis: an exploratory study.

Richard A Wilkins,Anthony C Redmond,Philip S Helliwell,Heidi J Siddle

doi:10.1007/s10067-016-3304-z

Abstract

Dactylitis is a common feature of psoriatic arthritis (PsA); local physical trauma has been identified as a possible contributing factor. The aim of this study was to explore differences in forefoot plantar pressures in patients with PsA with and without dactylitis and compare to healthy controls. Thirty-six participants were recruited into three groups: group A PsA plus a history of dactylitis; group B PsA, no dactylitis; group C control participants. Forefoot plantar pressures were measured barefoot and in-shoe at the left second and fourth toes and corresponding metatarsophalangeal joints. Temporal and spatial parameters were measured and data from the foot impact scale for rheumatoid arthritis (FIS-RA), EQ5D and health assessment questionnaire (HAQ) were collected. Pressure time integral peak plantar pressure, and contact time barefoot and in-shoe were not significantly different between groups. Temporal and spatial parameters reported no significant differences between groups. ANOVA analysis and subsequent post hoc testing using Games-Howell test yielded significance in FIS-RA scores between both PsA groups versus controls, A p ≤ 0.0001 and PsA group B p < 0.0001 in the FIS-RA impairment and footwear domain, PsA group A p < 0.03 and PsA group B p ≤ 0.05 in the FIS-RA activity and participation domain compared to controls. This is the first exploratory study to investigate forefoot plantar pressures in patients with and without historical dactylitis in PsA. FIS-RA scores indicate PsA patients have significant limitations compared to controls, although a history of dactylitis does not appear to worsen patient reported outcomes.

Highlights

Levels of peripheral joint damage are lower in psoriatic arthritis (PsA) compared to rheumatoid arthritis (RA), foot impairment and disability are reported in two thirds of patients at the forefoot [1]
FIS-RA a mean FIS-RAIF score of 7.16 in group A and 6.83 in group B compared to 0.41 in the control group, and a mean FIS-RAAP score of 8.75 in group A and 5.75 in group B compared to 0.16 in the control group; analysis of variance (ANOVA) analysis and subsequent post-hoc testing identified statistically significance differences between groups in FIS-RA scores (Table 2). In both domains of the FIS-RA, there was a significant difference between both PsA groups compared to the control group; PsA group A p = 0.0001 and PsA group B p = 0.0001 in the FISRAIF domain, PsA group A p = 0.03 and PsA group B p = 0.05 in the FIS-RAAP domain
Differences in PsA Peak plantar pressure (PPP), pressure time integral (PTI) and contact area were not identified, the results indicate that pressure may not be as relevant to the cause of trauma as previously hypothesised

Summary

Introduction

Levels of peripheral joint damage are lower in psoriatic arthritis (PsA) compared to rheumatoid arthritis (RA), foot impairment and disability are reported in two thirds of patients at the forefoot [1]. Despite lower levels of peripheral joint damage the effect on patients reported pain and disability are significant [2, 3]. Dactylitis is one of the most common features of PsA occurring in around 40 % of cases. It is classed as a hallmark feature of the disease and forms part of the classification criteria for PsA [4]. Dactylitis, referred to as sausage digit presents clinically as an acute painful inflammation of the digit which in the chronic phase can remain swollen following the subsidence of acute inflammation

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