The absence of a metal-on-metal bearing does not preclude the formation of a destructive pseudotumor in the hip—a case report

Does Surface Topography Play a Role in Taper Damage in Head-neck Modular Junctions?

“…Corrosion products can trigger adverse local tissue reactions (ALTRs) and subsequent revision surgery. Multiple case reports have implicated corrosion of modular head-neck junctions as the cause of hip pain resulting in revision surgery [2,26,28,29,33,37,38]. So far the largest clinical series have suggested that between 1.8% and 2.3% of patients undergoing THA with metal-on-polyethylene bearings will undergo revision surgery per year because of modular head-neck junction corrosion [9,10].…”

“…Factors previously identified as increasing corrosion and fretting of modular head-neck junctions include design characteristics such as larger femoral head diameter [5,12], longer femoral neck offset [4,11,16,25], larger angular mismatch between the stem taper and head taper [2,6], and higher flexural rigidity [17]. Surgical assembly technique such as the force and angle at which the surgeon impacts the femoral head onto the stem taper [32] and the presence of fluid or debris on the taper surfaces during surgical assembly [16,21] can negatively affect the taper's initial stability.…”

“…(2) How are initial surface topography, flexural rigidity, taper angle mismatch, and time in situ related to visual taper damage scores for CoCr/ CoCr couples? (3) How are initial surface topography, flexural rigidity, taper angle mismatch, and time in situ related to visual taper damage scores for CoCr/Ti couples?…”

Metal Artifact Reduction Sequence MRI Abnormalities Occur in Metal-on-polyethylene Hips

“…These reports have focused on metallosis presumably as a result of corrosion at the head and neck junction or the neck-stem modular junction in modular stems. All of these patients were symptomatic on presentation [2,6,9,10,13,17]. Williams et al [20] reported abnormalities through ultrasound in three of 24 asymptomatic patients with MoP bearings.…”

“…These aggressive periarticular granulomatous masses were usually diagnosed on pelvic CT or ultrasound rather than MRI in an era of poor-quality polyethylene. Recently MARS MRIs have been used to document ALTRs after MoP total hips that have no discernible reasons for symptoms [2,6,9,10,13,17]. These reports have focused on metallosis presumably as a result of corrosion at the head and neck junction or the neck-stem modular junction in modular stems.…”