Background. Misdiagnosed/chronic Achilles tendon injuries are rare and disabling for patients. Surgical treatment of this type of injury guarantees optimal clinical and functional results by exploiting the proven regenerative potential of allografts of decellularized dermis and growth factors released from platelets concentrated in plasma. In this study, we mainly describe the surgical technique, original and not found in the literature, of using a biological graft (allograft of decellularized dermis) and homologous thrombin-activated PRP in a single step. Secondly, we evaluated results obtained at a minimum follow-up of 18 months and a maximum of 24 months. Methods. All patients of this study complained of pain, but above all of severe functional limitation that Achilles tendon injury had been causing for more than a month. Surgical approach, always used by the first author, respected predefined steps: careful dissection and preparation of the peritendinous tissues from suture to the end of the procedure, tenorrhaphy and augmentation with allopatch to obtain a mechanically effective repair to avoid recurrences, and finally 'biological' augmentation with a unit of homologous thrombin-activated PRP. We offered to all patients a regenerative rehabilitation program post-operatively. Results. All patients were evaluated clinically (functional clinical tests and questionnaires) and instrumentally (elastosonography and perfusion MRI). In all patients pain was resolved and district function and kinetic chains improved with resumption of daily activities, work and sports. Conclusions. The optimal results found confirm the regenerative potential of decellularized dermis allograft and PRP (homologous and thrombin-activated) in our study. This potential can also be exploited in cases of severe tendon destructuring and limited 'intrinsic' regenerative potential and at any age. The proposed one-step surgical technique of a double augmentation therefore appears useful, safe, reproducible and applicable in all chronic tendon lesions with low regenerative potential.