Adverse Reactions to Metal Debris (ARMD)

Adverse reactions to metal debris (ARMD) and adverse local tissue reactions (ALTR) are mainly observed in total hip arthroplasty (THA) and hip resurfacing arthroplasty with metal-on-metal (MoM) articulations. Metal wear particles and metal ions cause the formation of non-infectious, non-neoplastic pseudotumor lesions and extensive fluid correction around the joint, which if allowed to progress, can lead to soft tissue damage in the joint capsule, muscle tissue, and bone tissue around the implant [1]. Similar pathologies can occur from corrosion and fretting (taper corrosion, trunnionosis) at the junctions between the metal head and stem neck, including THA with a metal head and polyethylene liner (metal-on-polyethylene: MoP) articulations (Fig. 85.1) [2, 3]. Although metal allergy disorders, such as McKee-Farrar-type MoM THA and disorders of the junctions between the metal head and stem neck have been reported before the 1990s [4], ARMD-related disorders have gained great attention as the clinical use of MoM THA/resurfacing hip prostheses using large-diameter femoral heads rapidly became widespread in the late 1990s [1]. In the pathogenesis of ARMD, cobalt and chromium ions have been implicated in stimulating the migration of T lymphocytes and the activation of macrophages [5]. ARMD is rare in THAs without cobalt-chromium metal for articulation or stem neck junctions [6].