Surface Treatment of Cementless Cups and Stems

In recent years, cementless total hip arthroplasty (THA) has become mainstream, and from the viewpoint of long-term durability of cementless cups and stems, it is important to achieve biologically firm fixation with direct contact between bone tissue and implant surface without fibrous soft tissue intervention. This requires good initial implant fixation. Factors that influence long-term durability and initial fixation include implant material, design, and surface finish [1]. For cementless cup stems to adhere to bone, the implant must be made of a material with a high affinity to bone, and a scaffold for osteogenesis must be formed by roughening the surface or forming a porous structure. Metals such as pure titanium (Ti), titanium alloys, and cobalt-chromium (Co-Cr) alloys have been used. It is also known that the surface coating of ceramic biomaterials with high biological activity, such as hydroxyapatite (HA), promotes new bone formation.