Soft tissue thickness under the metatarsal heads is reduced in older people with toe deformities

Abstract

The purpose of this study was to determine whether thickness of the plantar soft tissue (ST) under the metatarsal heads (MTH) differed between older individuals with and without toe deformities. Non-weightbearing total ST and fat pad (FP) thickness at the heel, 1st metatarsal head (1MTH) and 5th metatarsal head (5MTH) were measured using ultrasound in 312 men and women aged over 60 years. Each participant had their feet assessed for the presence of hallux valgus or lesser toe deformities. Total ST and FP thicknesses in those with hallux valgus (n=36) or lesser toe deformities (n=72) were compared to gender-, age- and BMI-matched controls using independent t-tests. Individuals with hallux valgus had significantly reduced total ST thickness under 1MTH compared to controls (7.4 ± 1.6 mm vs. 8.5 ± 1.5 mm; p = 0.002). Similarly, individuals with lesser toe deformities displayed significantly reduced total ST thickness under 5MTH compared to controls (5.1 ± 1.0 mm vs. 5.5 ± 1.3 mm; p = 0.01). As FP thickness did not differ between cases and controls, we speculate that the musculotendinous complex is compromised, and may result in reduced toe function in those with toe deformities.