Risk factors related to functional tasks in patients with plantar fasciitis – a paired case-control study

Abstract

Introduction: The foot is a structure responsible for the functions of balance, locomotion, impact absorption and overload support. When the foot is injured and the pain occurs, it can cause changes in movement and induce asynchrony in other structures such as the ankle, knee and hip. Studies indicate that there is a relationship between age, body mass index, foot posture and limitation of ankle dorsiflexion as risk factors in the development of plantar fasciitis. Methods: This study has a cross-sectional observational case-control design. All participants read and signed the informed consent form, which was approved by the ethics committee with registration CAAE37800114.6.0000.5235. Individuals with unilateral plantar fasciitis and healthy individuals matched by age, body mass index and gender (p>0.05) were recruited (n=14). The evaluation consisted of completing questionnaires on demographic data, pain characteristics, pain intensity (pain scale from 0 to 10), lower limb functionality and kinematic assessment. The data analyzed were obtained through the functional tasks “walking freely” and “taking a step forward”. For statistical analysis, Student's t-test or Mann-Whitney U test and correlation analysis using the Pearson method were used, in addition to verification of the effect size. A significance value of less than 5% (p<0.05) was considered. Results: Most patients with plantar fasciitis were female (n=9) and had a mean age of 48.8 years. Patients with plantar fasciitis had a mean of 5.21 on the numerical pain scale and a mean frequency of 6.71 days per week. All points evaluated in algometry had a lower pressure pain threshold on the affected side compared to the contralateral side and the control individual. The functional limitation of the lower limbs showed correlation with the tools used to measure pain. The ankle dorsiflexion angle at the time of departure was smaller in patients compared to the control group (FP = 97.16°) and (C = 90.39°). At the time of heel touch, both groups were in plantar flexion during the functional tasks, with a higher mean for the control group, (FP = 4.28°) and (C = 5.06°) in “walking freely” and (FP = 6.15°) and (C = 7.98°) in “take a step forward”. The mean plantar flexion angle at the time of forefoot withdrawal was smaller in patients than in controls during the “walking freely” task (FP = 8.90°) and (C = 14.93°) and “take a step forward” (FP = 0.59°) and (C = 2.10°). The movement pattern correlated with data on the pressure pain threshold and the pain intensity scale, suggesting compensatory mechanisms for performing functional tasks. Conclusion: Pain directly interfered with the lower limb functionality scale, leading to functional limitations. The ankle movement (start angle, heel strike and foot withdrawal) of patients with plantar fasciitis showed differences when compared to the healthy side and the matched control group. There was a correlation between the modification of ankle movement and pain, lower extremity function and foot posture.