An equinus deformity of the ankle accounts for only a small amount of the increased forefoot plantar pressure in patients with diabetes

Patients with diabetes mellitus may develop plantar flexion contractures (equinus) which may increase forefoot pressure during walking. In order to determine the relationship between equinus and forefoot pressure, we measured forefoot pressure during walking in 27 adult diabetics with a mean age of 66.3 years (SD 7.4) and a mean duration of the condition of 13.4 years (SD 12.6) using an Emed mat. Maximum dorsiflexion of the ankle was determined using a custom device which an examiner used to apply a dorsiflexing torque of 10 Nm (SD 1) for five seconds. Simple linear regression showed that the relationship between equinus and peak forefoot pressure was significant (p < 0.0471), but that only a small portion of the variance was accounted for (R-2 = 0.149). This indicates that equinus has only a limited role in causing high forefoot pressure. Our findings suggest caution in undertaking of tendon-lengthening procedures to reduce peak forefoot plantar pressures in diabetic subjects until clearer indications are established.