Distribution and correlates of plantar hyperkeratotic lesions in older people

Plantar hyperkeratotic lesions are common in older people and are associated with pain, mobility impairment and functional limitations. However, little has been documented in relation to the frequency or distribution of these lesions. The aim of this study was to document the occurrence of plantar hyperkeratotic lesions and the patterns in which they occur in a random sample of older people.

A medical history questionnaire was administered to a random sample of 301 people living independently in the community (117 men, 184 women) aged between 70 and 95 years (mean 77.2, SD 4.9), who also underwent a clinical assessment of foot problems, including the documentation of plantar lesion locations, toe deformities and the presence and severity of hallux valgus.

Of the 301 participants, 180 (60%) had at least one plantar hyperkeratotic lesion. Those with plantar lesions were more likely to be female (χ² = 18.75, p < 0.01; OR = 2.86), have moderate to severe hallux valgus (χ² = 6.15, p < 0.02; OR = 2.95), a larger dorsiflexion range of motion at the ankle (39.4 ± 9.3 vs 36.3 ± 8.4°; t = 2.68, df = 286, p < 0.01), and spent more time on their feet at home (5.1 ± 1.0 vs 4.8 ± 1.3 hours, t = -2.46, df = 299, p = 0.01). No associations were found between the presence of plantar lesions and body mass index, obesity, foot posture, dominant foot or forefoot pain. A total of 53 different lesions patterns were observed, with the most common lesion pattern being "roll-off" hyperkeratosis on the medial aspect of the 1^st metatarsophalangeal joint (MPJ), accounting for 12% of all lesion patterns. "Roll-off" lesions under the 1^st MPJ and interphalangeal joint were significantly associated with moderate to severe hallux valgus (p < 0.05), whereas lesions under the central MPJs were significantly associated with deformity of the corresponding lesser toe (p < 0.05). Factor analysis indicated that 62% of lesion patterns could be grouped under three broad categories, relating to medial, central and lateral locations.

Plantar hyperkeratotic lesions affect 60% of older people and are associated with female gender, hallux valgus, toe deformity, increased ankle flexibility and time spent on feet, but are not associated with obesity, limb dominance, forefoot pain or foot posture. Although there are a wide range of lesion distribution patterns, most can be classified into medial, central or lateral groups. Further research is required to determine whether these patterns are related to the dynamic function of the foot or other factors such as foot pathology or morphology.