Callus Location in Flatfoot Deformity
Calluses specific to flatfoot are located on the medial (inner) midfoot and under the medial aspect of the forefoot, particularly beneath the first and second metatarsal heads, due to abnormal weight distribution and increased pressure from the collapsed medial longitudinal arch.
Biomechanical Basis for Callus Location
The characteristic callus pattern in flatfoot results from altered biomechanics when the medial longitudinal arch collapses 1. When arch support is lost, weight distribution shifts medially, creating excessive pressure points that trigger hyperkeratosis formation 1.
Primary Callus Sites
Medial midfoot: This area develops calluses from direct ground contact when the arch flattens, as the normally elevated medial border of the foot now bears abnormal weight 2, 1
Plantar surface under medial metatarsal heads: The first and second metatarsal heads experience increased loading in flatfoot deformity, leading to callus formation in these weight-bearing areas 3
Medial border of the foot: The collapsed arch causes the medial foot border to contact the ground abnormally during gait 1
Clinical Recognition and Management
Key Diagnostic Features
Pain under the medial midfoot combined with visible callus formation strongly suggests flatfoot-related mechanical overload 2. The calluses appear as hard, thickened, yellowish areas at these characteristic pressure points 4.
Treatment Approach
Professional debridement: Calluses should be removed by a trained healthcare provider to reduce plantar pressure and prevent complications 5, 4
Address underlying biomechanics: Custom-made insoles or orthotic devices are essential to redistribute pressure away from the collapsed arch and prevent callus recurrence 4, 6
Footwear modifications: Properly fitting shoes with adequate arch support help reduce abnormal pressure distribution 5, 4
Important Clinical Pitfall
Do not treat calluses in isolation without addressing the underlying flatfoot deformity 4. Repeated debridement without mechanical correction leads to rapid recurrence and continued pain 2. The goal is rebalancing forces acting on the arch through orthotic intervention or, in refractory cases with persistent pain despite conservative treatment, surgical correction 2, 1.