The effect of pes cavus on foot pain and plantar pressure.

BACKGROUND: Clinical management of patients with painful pes cavus is challenging because the mechanism of foot pain is poorly understood. The purpose of this study was to explore the influence of various pes cavus aetiologies on foot pain and plantar pressure characteristics, and to identify the relationship between foot pain and plantar pressure.

METHODS: Seventy subjects were recruited for this study. They included 30 subjects with pes cavus of unknown aetiology (idiopathic), 10 subjects with pes cavus of neurological aetiology (neurogenic) and 30 subjects with a normal foot type. The presence and location of foot pain was recorded and barefoot plantar pressures were measured using the EMED-SF platform for the whole foot, rearfoot, midfoot and forefoot regions.

FINDINGS: Subjects with pes cavus of either idiopathic or neurogenic aetiology reported a higher proportion of foot pain (60%) compared to subjects with a normal foot type (23%) (P=0.009). Pressure-time integrals under the whole foot, rearfoot and forefoot regions in pes cavus, of both idiopathic and neurogenic origin, were higher than in the normal foot type (P<0.01). Pressure-time integrals in subjects reporting foot pain were higher than for pain free subjects (P<0.001). There was a significant correlation between pressure-time integral and foot pain (r=0.49, P<0.001).

INTERPRETATION: Foot pain is a common finding among individuals with pes cavus. Regardless of aetiology, pes cavus is characterized by abnormally high pressure-time integrals which are significantly related to foot pain. An understanding of the relationship between pes cavus pressure patterns and foot pain will improve the clinical management of these patients.