Relation Between Calcaneal Fat Pad Thickness and Plantar Foot Ulceration in Patients With Type 2 Diabetes Mellitus

Thinning of fat pads may elevate the risk of developing plantar foot ulcers potentially resulting in lower-extremity amputations. Evaluating whether fat pad thickness is associated with plantar foot ulceration could aid in early risk detection. This study therefore aims to compare fat pad thickness between type 2 diabetes mellitus (T2DM) patients with and without plantar foot ulcers using MRI.

This retrospective cross-sectional study included patients diagnosed with T2DM of whom a nonweight bearing MRI of the ankle or foot was available. The thickness of the calcaneal fat pad was measured in the sagittal plane, measuring perpendicularly from the lowest cortex of the calcaneal bone to and including the skin. Calcaneal fat pad thickness was compared between T2DM patients with and without plantar foot ulceration.

In total, 42 patients were included of which 16 in the T2DM group with plantar foot ulceration. The calcaneal fat pad was significantly thinner in T2DM patients with plantar foot ulceration compared to those without plantar foot ulceration (15.7 ± 3.2 mm vs. 18.6 ± 2.8 mm, p = 0.004).

This study established an initial association between fat pad thickness and plantar foot ulceration in T2DM patients. Our findings suggest that a reduction in calcaneal fat pad thickness may decrease the shock-absorbing ability of the plantar fat pads, making the underlying tissue more vulnerable to injury, increasing the risk of developing plantar foot ulcers. The initial association between fat pad thickness and foot ulceration should be further explored to discover its potential in clinical practice.