Abstract
Research Type:
Level 2 - Prospective comparative study, Meta-analysis of Level 2 studies or Level 1 studies with inconsistent results
Introduction/Purpose:
Plantar fasciitis (PF) is a common cause of heel pain. Despite its high incidence, the relationship between PF and foot biokinetics is not fully understood. Previous research has focused on the windlass mechanism and the Achilles-calcaneus-plantar system, emphasizing the importance of the first metatarsophalangeal (1MTP) joint motion and plantar fascia tension. This study aims to investigate the role of the windlass mechanism in PF by analyzing 1MTP dorsiflexion during gait and pressure distribution using pedobarography. We hypothesize that individuals with PF have decreased 1MTP dorsiflexion and altered pressure patterns compared to healthy controls, which may contribute to their symptoms.
Methods:
This study analyzed data from an ongoing cross-sectional study of 11 subjects recruited from a single institution and categorized into clinically diagnosed PF (n=5, mean age 47±7 years, 5 female) and healthy controls (n=6, mean age 35±7 years, 4 female, 2 male). Gait analysis was performed using a 20-camera high-speed motion capture system and a pressure plate embedded in a 12-foot walkway. Each participant completed five walking trials at a self-selected speed. The Ghent multi-segment foot model was used to capture motion and calculate maximum 1MTP angles and range of motion (ROM) during the stance phase (Fig.1A). A foot pressure pad was used to assess dynamic peak plantar pressure in the medial and lateral forefoot during the stance phase of gait. A multivariate analysis of variance (ANOVA) was conducted to compare group differences in maximum 1MTP angles and dynamic peak plantar pressures. Statistical significance was set at P< 0.05.
Results:
The maximum 1MTP dorsiflexion angle (Fig. 1B) was reduced in the PF group compared to controls (62.2º±14.7 vs. 75.0º±11.7; p< 0.001). Although not statistically significant, PF patients trended towards shifting dynamic plantar pressure laterally (63.7 N/cm2 ± 20.4 vs. 45.7 N/cm2 ± 22.3; p=0.173) compared to controls (Fig. 1C-D). Our results suggest that plantar fascia tightness could limit 1MTP dorsiflexion as commonly observed in functional hallux rigidus. This tightness would trigger the windlass mechanism earlier, resulting in increased forefoot supination during late stance as a compensatory mechanism. Alternatively, these findings may represent an adaptive mechanism to avoid late stance pain.
Conclusion:
Patients with PF had reduced dynamic 1MTP dorsiflexion ROM and trended towards shifting their plantar pressure distribution laterally compared to healthy controls, indicating altered foot biokinetics. Preliminary findings suggest that PF may be associated with plantar fascia tightness and limited function in the forefoot. Limitations in dorsiflexion at the 1MTP may restrict forward movement of the tibia during stance phase, leading to compensatory mechanisms that may cause abnormal foot and ankle movements. Although these compensatory movements are often tolerated, they may contribute to the clinical presentation of PF. Ongoing research with additional subjects is needed to further investigate these mechanisms.
Figure 1: A) Ghent multi-segment foot model markers placement; B) Hallux dorsiflexion range of motion; C) Foot pressure map; D) Peak pressure mask lateral forefoot