Objectively Assessed Foot and Ankle Characteristics in Patients with Systemic Lupus Erythematosus: A Comparison with Age- and Sex-Matched Controls

SLR - March 2021 - Renier

Reference: Stewart S, Dalbeth N, Aiyer A, Rome K. Objectively Assessed Foot and Ankle Characteristics in Patients with Systemic Lupus Erythematosus: A Comparison with Age- and Sex-Matched Controls. Arthritis Care Res (Hoboken). 2020 Jan;72(1):122-130. doi: 10.1002/acr.23832. Epub 2019 Dec 10. PMID: 30629828.

Level of Evidence: 3

Scientific Literature Review

Reviewed By: Edee S. Renier, DPM 
Residency Program: Swedish Medical Center – Seattle, WA

Podiatric Relevance: Podiatry plays an incredibly important role in the comprehensive care of Systemic Lupus Erythematosus (SLE) patients and should not be overlooked. The feet are disproportionately affected by SLE as compared to the hands and wrists. While most SLE patients suffer from foot and ankle ailments, the effect on foot type, muscle strength and gait pattern have not previously been studied. This study matched an SLE cohort to a control cohort by age and sex to isolate and evaluate functional and objective foot concerns specific to SLE patients. 

Methods: Fifty-four patients with SLE and 56 control patients were age and sex matched and objective data as well as self reported data was collected and compared. Muscle strength, joint motion, foot posture, foot problems, protective sensation, vibratory sensation, ABI, plantar pressure, and spatiotemporal gait analysis data was collected for all patients. Patients also self-reported foot pain and impairment. 

Results: When age and sex were matched, the SLE affected population was more likely to have a higher tender joint count (P < 0.001) and swollen joint count (P = 0.025). With regards to biomechanical function, the study population had lower muscle strength with dorsiflexion, plantarflexion, inversion and eversion of the foot (all P <0.001). They had lower stride length with higher step, swing, stance and double support times (all P < 0.001). There was a significantly decreased velocity and cadence in the SLE cohort (all P < 0.001). The study population was also more likely to demonstrate higher vibration perception thresholds (P =0.001), and abnormal ABI’s (P = 0.044). SLE patients demonstrated higher foot postural index (P =0.007), indicating a pronated foot posture, with higher peak pressures and pressure-time integrals at all seven regions of the plantar foot (P = 0.001). They reported worse foot pain on the visual analog scale, Manchester Foot Pain and Disability Index, and Lower Limb Task Questionnaire (all P < 0.001). 

Conclusions: The authors conclude that patients with SLE exhibit objective evidence of foot and ankle disease, including reduced muscle strength, altered plantar pressures, gait pattern changes, and increased pain as compared to age and sex matched controls. Currently SLE patients do not have a standard referral to podiatric care specialists and this study suggests that they are at significantly increased risk for foot and ankle ailments. Similar to the comprehensive multidisciplinary care that Diabetic patients receive, rheumatologic patients should routinely be referred to podiatric physicians for early care and management of podiatric concerns.