Component Bone Interface in Cementless Hip Arthroplasty

Abstract

Cemented total hip replacement is one of the most successful orthopaedic procedures, with reliable relief of pain and restoration of function. Long-term results have improved with modern cementation techniques resulting in the use of total hip arthroplasty in an increasingly young patient population. Despite reported stress survival rates of up to 98% at 20 years in young patients [1] other series report higher implant loosening rates [2–4]. Direct contact between cement and bone can occur but is rare, the usual interface being a fibrohistiocytic membrane described by Fornasier et al. [5] who also describe an inevitable loosening cascade at the cement-bone interface. Other factors implicated in the loosening of cemented prostheses include mechanical degradation of the acrylic bone cement with time [6, 7], impairment of mechanical strength of cement by contaminants [8], compromise of the host tissue by monomer leakage [9], and thermal injury to the bone during polymerisation [10], although this is disputed [11]. In addition, while cement is tolerated in bulk, it is known that particulate cement is ingested by and activates inflammatory cells, thus mediating osteolysis. These observations have stimulated interest in the development of a direct biological bond between prosthesis and bone using cementless fixation.