Technical Note:Is Corrosion a Threat to the Strength of the Taper Connection in Femoral Components of Total Hip Replacements?

The Distribution and Severity of Corrosion Damage at Eight Distinct Zones of Metallic Femoral Stem Implants

“…Eight distinct zones of the stem tapers including anterior-distal, anterior-proximal, medial-distal, medial-proximal, posterior-distal, posterior-proximal, lateral-distal, and lateral-proximal were scored and statistically compared to identify the zone(s) with the most severe corrosion damage in the retrieved implants studied in this work. It is noted that there are several studies in the literature that chose to score stem tapers holistically, not locally [9,10,[24][25][26].…”

Standardizing terms for tribocorrosion-associated adverse local tissue reaction in total hip arthroplasty

“…2). There is some controversy as to whether this is more common in mixed-alloy settings [13,14], which highlights the need for additional research to clarify this finding because there may be bias introduced by evaluating only retrieved implants (retrievals are primarily failed total hips, and corrosion may contribute to a failure, without being recognized [15,16]). Furthermore, retrieval laboratories estimating prevalence of corrosion based on visual inspection may have poor accuracy for lower grades (Goldberg 1-2) [17].…”

“…Some retrieved tapers show evidence of etching and grain egression (a mechanism of fatigue-crack initiation) at these interfaces, suggesting macroscopic movement [24]. Furthermore, corrosion at the interface may lead to instability and macromotion, making them further susceptible to abrasive wear [17,24,25], although this may be prosthesis specific [16].…”

Do Well-functioning THAs Retrieved at Autopsy Exhibit Evidence of Fretting and Corrosion?

“…The majority of studies concerning THA fretting and corrosion have been limited to analysis of revised THAs [15], although the implants considered in these studies were often removed for diagnoses other than ALTRs, including aseptic loosening, infection, instability, fracture, implant malpositioning, leg-length discrepancy, pain, polyethylene wear, or osteolysis [10,20,27]. A recent retrieval study observed less damage in a small cohort of THAs retrieved at autopsy than THAs from revision surgery [12]. Overall, little is known about the condition of head-neck tapers in well-functioning THAs with respect to fretting and corrosion.…”

“…Corrosion at the head-neck junction has been shown to weaken the mechanical strength of femoral stems and taper locking strength, leading to fatigue fracture [9] and dissociation [2,29]. Femoral head pull-off force is considered an indirect measurement of taper locking strength and has been positively associated with stem trunnion damage [12]. Assessment of trunnion fretting and corrosion damage of retrieved implants continues to identify risk characteristics of THA designs and modular connections such as trunnion geometry and head material [13,19,20].…”