Leg length discrepancy is not a risk factor for plantar fasciitis.

PURPOSE: Plantar fasciitis (PF) is a main source of heel pain, and only about one-third of patients have bilateral symptomatic involvement, although age, body mass index (BMI), and physical activities are known risk factors. The high prevalence of unilateral involvement is poorly understood. We aimed to assess the potential association between PF and the leg length discrepancy (LLD) in unilateral PF. METHODS: A transversal case-control study was conducted from January 2019 to December 2020, including 120 participants allocated to two groups matched by BMI and sex: cases (with a diagnosis of PF; 50 ± 13 years) and control (without foot pain; 40 ± 15 years). For both groups, a difference greater than 0.64 cm in the scanometry determined the criteria for the presence of LLD. RESULTS: The multivariate logistic regression analysis showed an independent association of PF only with age (p < 0.001), and no association with LLD. We did not observe differences in the mean discrepancy (1.37 ± 0.83 cm in the PF group in comparison with 1.13 ± 0.37 cm in the control group, [p > 0.05]) or in the prevalence of LLD between groups (48% [n = 29] in the PF group compared with 42% [n = 25] in the control group, [p > 0.05]). In the PF group, 80% of the participants reported unilateral pain. We observed a higher prevalence of pain in the shorter limb (p < 0.05). CONCLUSION: Age was the only factor associated with the diagnosis of PF when groups were matched by sex and BMI. LLD was not an independent factor associated with the diagnosis of PF. However, when PF is unilateral, the shorter limb is more affected with 70% of prevalence. LEVEL OF EVIDENCE: Level III, case-control.

Differences in the cross-sectional area along the ankle tendons with both age and sex.

Increasing age appears to influence several morphologic changes in major tendons. However, the effects of aging on the cross-sectional area (CSA) of different ankle tendons are much less understood. Furthermore, potential differences in specific tendon regions along the length of the tendons have not been investigated in detail. Sixty healthy adult participants categorized by age as young (n = 20; mean ± SD age = 22.5 ± 4.5 years), middle-age (n = 20; age = 40.6 ± 8. 0 years), or old (n = 20; age = 69.9 ± 9.1 years), from both sexes, were included. The tendon CSA of tibialis anterior (TA), tibialis posterior (TP), fibularis (FT), and Achilles (AT) was measured from T1-weighted 1.5 T MR images in incremental intervals of 10% along its length (from proximal insertion) and compared between different age groups and sexes. The mean CSA of the AT was greater in the middle-age group than both young and old participants (p < 0.01) and large effect sizes were observed for these differences (Cohen's d > 1). Furthermore, there was a significant difference in CSA in all three groups along the length of the different tendons. Region-specific differences between groups were observed in the distal portion (90% and 100% of the length), in which the FT presented greater CSA comparing middle-age to young and old (p < 0.05). In conclusion, (1) great magnitude of morpho-structural differences was discovered in the AT; (2) there are region-specific differences in the CSA of ankle tendons within the three groups and between them; and (3) there were no differences in tendon CSA between sexes.