Background Foot involvement is the most common cause of disability in patients with rheumatoid arthritis (RA). The forefoot remains the most affected location.
Objectives Investigate the forefoot injuries in patients with RA and evaluate its impact on walking.
Methods Cross-sectional study of 33 patients with rheumatoid arthritis. Patients with static lower limb disorder or foot injury from other origin were excluded.Demographic and clinico-biological characteristics were collected: age, sex, BMI, disease duration, tender joint count, swollen joint count, foot pain evaluated on an VAS, squeeze test in foot, various podiatric abnormalities, sedimentation rate in the first hour, C reactive protein, rheumatoid factor and anti-CCP. Disease activity was evaluated by DAS28, CDAI, SDAI and DAS44. The effect on walking was studied by the HAQ (specific item of walking) and the French version of FFI (Foot Functional Index) which consists on 23 items, divided into 3 sections: pain, function and limitation of activity. Statistical analysis was performed using SPSS21 software.
Results 33 patients followed for RA were included. The mean age of our patients was 49.39±10.52 with a female predominance (87.9%). Mean duration of the disease was 9.96±7.49 years. 21 (95.5%) of patients were seropositive. Mean DAS28 was 5.53 (4.58–6.50) and mean HAQ was 1.37 (0.70–2.10). 54.5% of our patients reported right forfoot pain and 57.6% of them reported left forefoot pain; with predominant metatarsalgia (right 54.5% and left 57.6%). 33.3% had forfoot pain in the day of the examination and 69.7% (23) had a positive squeeze test. 18 (54.5%) patients had a foot podiatric abnormalities. They are represented by: right hallux valgus (39.4%), left hallux valgus (39.4%), right quintus varus (12.1%), left quintus varus (9.1%), right claw toe (9.1%), left claw toe (12.1%), right triangular foot (6.1%) and left triangular foot (6.1%).
Mean FFI was 52.35 (34.73–71.43), and mean FFI-function was 53.66 (34.44–74.99). 27.3% (9) of patients had walking difficulty according to item 4 of HAQ. A statistically significant association was found between a high FFI-function and metatarso-phalangeal pain (p=0.029), anterior plantar pain (p=0.018) and a positive squeeze test (p=0.01). Impairment of walking assessed by FFI-function was positively correlated with pain (r=0.58,p=0.0001) and discomfort in forfoot (r=0.452,p=0.008), VAS pain (r=0.48,p=0.005) and global gene VAS (r=0.70,p=0.001) associated with disease. Disease activity was positively correlated with FFI-function (DAS28 (r=0.48,p=0.005), CDAI (r=0.6-p=0.0001), SDAI (r=0.60,P=0.0001) and DAS44 (r=0.55, p=0.001)). The difficulty of walking assessed by item 4 of HAQ was associated with metatarso-phalangeal pain (p=0.01), and was not influenced by adaptation of the footwear (p=0.015). Also, item 4 was statistically associated with disease activity (DAS28 (p=0.028) and SDAI (p=0.049)) and impaired function evaluated by FFI (p=0.001) and particularly FFI-Function (p=0.0001). Podological abnormalities were not statistically associated with either functional FFI or the item 4 of HAQ.
Conclusions Forefoot involvement is frequent during RA, particularly podiatric abnormalities. It generates a functional repercussion on walking which would be rather related to pain and disease activity than to podiatric abnormalities.
Disclosure of Interest None declared