Biomechanical properties of heel-pad and metatarsal head soft tissue and foot ulcers in patients with systemic sclerosis – a case control study

Background: Systemic sclerosis is a chronic disease of connective tissue accompanied with increased risk of foot ulcers. Biomechanical indexes (soft tissue thickness and compressibility) could affect the risk of this phenomenon.Objective: The aim of this study was assessment of heel pad and first metatarsal head soft tissue thickness and compressibility index in scleroderma patients with and without foot ulcers and comparison with healthy individuals.Methods: Heel pad thickness in standing(loaded) and lying(unloaded) positions was measured in 40 scleroderma patients by means of lateral foot radiography. Compressibility index was measured as the ratio of loaded to unloaded thickness. Also, soft tissue thickness of first metatarsal head was measured with ultrasound. Results were compared with 40 healthy controls of matched age and body mass index.Results: Among 40 scleroderma patients (36 females, 4 males) with mean age of 45 (±12) years and mean body mass index of 25.5 (±4) and mean disease duration of 10 years (±9.6), 8 (20%) had foot ulcers. Heel pad thickness (p-value 0.03) and compressibility index (p-value 0.005) in the dominant side and both-sides metatarsal head soft tissue thickness (P-value