Today, in the period of one year, in Brazil and throughout world, hundreds of thousands of surgical implants, both permanent and temporary, are carried out with a high cost for the patients, especially those of SUS – Sistema Único de Saúde. In addition, the SUS costs for treatment of infections that appear as a result of introduction of an implant into the human body create expenses about three times greater than the use of implants coated with biomaterials. Hydroxyapatite (HA) constitutes the base of one important group of biomaterials with excellent implant characteristics. Hydroxyapatite has been extensively studied, but the adherence relationship at the coating/substrate interface is not yet well understood. The coatings in this study were produced using substrates of AISI 316L stainless steel shaped as external fixation pins, with HA applied by a high energy plasma spray gun (HEP). The coating thicknesses were between 15µm and 98µm. The mechanical evaluation of coating adhesion was conducted by scratch testing with progressive loads. Results show an increase of failure load with an increase in thickness. The clinical evaluation was carried out in the Trauma and Orthopedics Sector of the Baleia Hospital, and shows a significant decrease in inflammatory response in the human body.