Background Systemic sclerosis (SSc) is rare disease featuring chronic autoimmune responses resulting in small vessel vasculopathy, autoantibody production and fibroblast dysfunction leading to increased deposition of extracellular matrix (with possible involvement of skin and internal organs such as gastrointestinal tract, heart, lung and kidneys). The combination of these pathogenetic events in organs and tissues carry an heterogeneous spectrum of illness, ranging from mild to severe and crippling disease. The mixture of joint/tendon inflammation, skin hardening and vascular involvement may involve the feet, yet few studies exist to determine the importance of pathologic abnormalities in the feet in SSc population.
Objectives The aim of the present study was to investigate the prevalence and importance of podiatric involvement in a consecutive series of SSc patients in comparison to Rheumatoid Arthritis (RA) subjects and a control group of healthy individuals.
Methods To this end a series of 34 SSc patients (M/F ratio 0.03, mean age 64, range 20-81), 20 RA patients (M/F ratio 0.25, mean age 66, range 40-81) and 34 healthy subjects (M/F ratio 0.36, mean age 63, range 24-85) were recruited.
The subjects underwent the following assessments:
Questionnaires to evaluate disability and foot function, pain and strength: Health Assessment Questionnaire disability index (HAQ DI), Visual Analogue Scales (VAS) for stiffness and pain, Foot Function Index With Verbal Rating Scales (FFI-5PT).
A thorough physical examination with assessment of foot deformities (such as claw toes, hallux valgus, hallux extensus), skin alterations (skin ulcers, hyperkeratosis, skin distrophies), nail alterations, evaluation of strength (Lovett-Martin test), joint stiffness, joint pain (modified Ritchie index).
Results Differences in questionnaires for disability (HAQ), foot function, pain and strength were of similar magnitude in SSc and RA subjects as compared to healthy individuals (with p values ranging from 0.001 to 0.0001), except for Ritchie index, which showed a statistical significant difference between RA and healthy subjects (p value <0.005) but not between SSc and healthy individuals.
Similar differences were outlined between RA and SSc individuals on the one hand and healthy subjects on the other hand in the prevalence of forefoot deformities (p<0.0001), with particular reference to hallux valgus (p<0.0001) and griffe deformities (p<0.01). In contrast, skin dystrophies and skin ulcers were exclusive features of SSc patients as compared to RA subjects and healthy individuals, with a prevalence respectively of 64% (as compared to 25% in RA subjects and 35% in healthy individuals p<0.01) and 21% respectively (as compared to none in RA subjects and in healthy individuals p<0.001).
Conclusions Podiatric involvement in SSc is frequent and seems to mirror Rheumatoid Artrhitis in respect to the magnitude of disability and joint dysfunction: distinctive features related to skin and vascular involvement and the possible occurrence of skin ulcers are also present. To better address this issue and to explore special podiatric needs in SSc subjects, further studies are warranted.
Disclosure of Interest None declared