The "short Achilles tendon" syndrome, characterised by limited dorsiflexion of the tibiotarsal joint, is not well-known but could be a disposing factor for trophic disorders and plantar ulcer related to hypersupport in the diabetic subject. We report two cases of multicomplicated diabetic patients treated during several months for plantar ulcer superinfected with underlying osteoarthrits, whose course became rapidly favourable after tenotomy of the Achilles tendon. This simple surgical act can be performed in ambulatory conditions under local anaesthesia. Functional disability is negligible. The benefit of this treatment as part of the curative or preventive therapeutic arsenal for care of the diabetic foot remains to be evaluated.