Taper Corrosion and Fretting

Fretting and Corrosion at Modular Junction

Taper corrosion in modular total hip arthroplasty was identified as a clinical concern already in the 1980s–90s. More modern design trends like metal-on-metal bearings, large heads, and modular necks have recently re-introduced implant corrosion as a clinical issue, being the cause for 4.2 % (Reference Della Valle Craig, AAHKS 2014, oral presentation) of all revisions and often with serious consequences.

Über uns

Source: The Effect of Bearing Surface on Corrosion at the Modular Junctions in Total Hip Arthroplasty
Selin Munir, Michael B.Cross, Reza Jenabzadeh, Anna Sokolova, Christina Esposito, Dennis Molloy,
William Walter, William Walter, Bernard Zicat – Poster, 25th ISTA 2012, Sydney

With kind permission of A/Prof. William L Walter, Mater Hospital, North Sydney, Australia

The amount of publications about this issue is numerous and there is consensus that the mechanism of taper corrosion is best characterized as mechanically assisted crevice corrosion. Although it seems fundamentally a crevice corrosion problem, mechanical fretting and wear also contribute in disruption of the atomically thin, protective oxide layers that border the crevice environment. Metal loss is a common finding at modular junctions of metal heads (cobalt chromium alloy) and their mating metal stem tapers. Even though it is more prevalent in large diameter metal-on-metal bearing tapers it is also observed in conventional metal-on-polyethylene components, even with 28 mm ball heads.

Metal loss (wear and corrosion) depends on a number of factors, including geometric variables, such as the dimensions and shape of the crevice at the taper interface, and the complex interplay of metallurgical, chemical, electrical, and tribological factors. Other factors like implantation time and the flexural rigidity of the femoral neck have also been identified as important variables.

The most recent presented publications on this topic related to ceramic modular heads and related to ceramic modular heads with a titanium alloy adapter sleeve (BIOLOX®OPTION).

Mechanically Initiated Interface Deterioration
(Wear, Fretting and Fretting Wear)

Wear is defined as surface damage characterized by progressive loss of material due to relative motion between opposing surfaces. 1 Fretting is defined as: „A special wear process that occurs at the contact area between two materials under load and subject to minute relative motion by vibration or some other force“ (ASTM Handbook on Fatigue and Fracture). Several authors have analyzed the necessary magnitude of motion needed to create this phenomenon and it has generally been defined as being very low, between 1 and 100 μm. 2,3 Given the magnitude of loading in the body, all modular junctions of prostheses are susceptible to fretting.

Chemical Initiated Interface Deterioration
(Corrosion and Crevice Corrosion)

Figure 1: Schematic of Metal-Oxide-Solution Interface with Protein Molecule and Voltage Variations

With kind permission of L. Gilbert

Corrosion in the engineer’s definition is the visible destruction of a structure and, in final consequence, the loss of function, while for a chemist it is an irreversible surface reaction of a material with its environment in a way that the material is consumed and its dissolved species become part of the environment. It is described as a surface degradation due to electrochemical interactions producing metallic ions and salts 4 and applies only to metallic materials. Only noble metals like gold have a surface which is self-protecting from corrosion, while all other metals and alloys in air spontaneously rely on a reaction with oxygen, forming a more or less protective (passivation) oxide layer, shown in Figure 1.

Any violation of this oxide film will lead to immediate corrosion (ion flow) until the film is formed again. 5 The time to rebuild a protective oxide layer again is called repassivation time. It is dependent on the metal composition and the availability of oxygen and takes only milliseconds 6, for Ti6Al4V about 60 ms 7.

References

  1. Fretting corrosion testing of modular implant interfaces. ASTM F1875-98, reapproved 2009
  2. Mutoh Y. Mechanism of fretting fatigue. JSME International Journal, 1995; 38(4), 405-415
  3. Bill RC. Review of factors that influence fretting wear. Materials Evaluation Under Fretting Condition, ASTM STP 780, American Society for Testing and Materials, New York, 1982, 165-182
  4. Collier P et al. Corrosion between the components of modular femoral hip prostheses. J Bone Joint Surg-Br1992; 74-B, 511-7
  5. Toni A et al. Clinical advantages and fretting concerns with modular neck total hip prosthesis, The institution of mechanical engineers, International conference “Refining future strategies in total hip replacement”, Transactions Volume two, Session 7-11, 2002
  6. Frangini S, Piconi C. Repassivation rates of surgical implantalloys by rotating disk scratching measurements. Materials and Corrosion, 2001; 52, 372-380
  7. Viceconti M et al. Fretting wear in modular neck hip prosthesis. JBiomed Mater Res 1997; 35-2, 207-216
  • Fundamentals

    Corrosion and Fretting Corrosion. A Glossary.

    by Robert M. Streicher PhD

Publications on Taper Corrosion and Fretting related to ceramic modular Heads

Fretting and Corrosion Changes in Modular Total Hip Arthroplasty
Do Ceramic Femoral Heads Reduce Taper Fretting Corrosion in Hip Arthroplasty?
A Retrieval Study

by Steven M. Kurtz PhD, Sevi B. Kocagöz BS, Josa A. Hanzlik MS, Richard J. Underwood PhD, Jeremy L. Gilbert PhD,
Daniel W. MacDonald MS, Gwo-Chin Lee MD, Michael A. Mont MD, Matthew J. Kraay MD, Gregg R. Klein MD,
Javad Parvizi MD, Clare M. Rimnac PhD

Abstract

Background

Previous studies regarding modular headneck taper corrosion were largely based on cobalt chrome (CoCr) alloy femoral heads. Less is known about headneck taper corrosion with ceramic femoral heads.

Questions/purposes

We asked (1) whether ceramic heads resulted in less taper corrosion than CoCr heads; (2) what device and patient factors influence taper fretting corrosion; and (3) whether the mechanism of taper fretting corrosion in ceramic heads differs from that in CoCr heads.

Methods

One hundred femoral head-stem pairs were analyzed for evidence of fretting and corrosion using a visual scoring technique based on the severity and extent of fretting and corrosion damage observed at the taper. A matched cohort design was used in which 50 ceramic headstem pairs were matched with 50 CoCr head-stem pairs based on implantation time, lateral offset, stem design, and flexural rigidity. Results Fretting and corrosion scores were lower for the stems in the ceramic head cohort (p = 0.03). Stem alloy (p = 0.004) and lower stem flexural rigidity (Spearman’s rho = - 0.32, p= 0.02) predicted stem fretting and corrosion damage in the ceramic head cohort but not in the metal head cohort. The mechanism of mechanically assisted crevice corrosion was similar in both cohorts although in the case of ceramic femoral heads, only one of the two surfaces (the male metal taper) engaged in the oxide abrasion and repassivation process.

Conclusions

The results suggest that by using a ceramic femoral head, CoCr fretting and corrosion from the modular head-neck taper may be mitigated but not eliminated.

Clinical relevance

The findings of this study support further study of the role of ceramic heads in potentially reducing femoral taper corrosion.

Fretting Corrosion and Trunnion Wear –
Is it also a Problem for Sleeved Ceramic Heads?

by Roman Preuss, PhD, Kim Lars Haeussler, Markus Flohr,and Robert M. Streicher, PhD

Abstract

Some modular bearing systems with large diameter metal-on-Metal articulation have exhibited higher than usual revisions due to corrosion and metal debris originating from modular metal connections. Large diameter ceramic-on-ceramic bearings exist, which use a titanium alloy adapter sleeve for fixing the ceramic ball head to the stem taper. This study addresses the issue of taper fretting and corrosion for large ceramic bearings with standard and a newly designed experimental setup. While large metal diameter heads have been shown to be a cause for failure of THA, our results demonstrate that large ceramic heads even with a metal adapter sleeve have no effect on corrosion of modular taper connections.

Corrosion in Modular Total Hip Replacements:
An Analysis of the Head-Neck and Stem-Sleeve Taper Connections

by Selin Munir, BE, MBiomedE, Michael B. Cross, MD, Christina Esposito, PhD, Anna Sokolova, and William L. Walter, MBBS, FRACS, FA OrthA, PhD

Abstract

In this retrieval study, modular junctions of retrieved S-ROM® implants were examined to determine the extent of corrosion at the head-neck and stem-sleeve junctions. Corrosion severity was graded in relation to the bearing surface material over time. It was found that the corrosion at the head-neck taper is greater for cobalt-chrome femoral heads compared to ceramic femoral heads. The stem-sleeve junction had significantly more corrosion damage (p < 0.05) in implants that had hard-on-hard bearing surfaces compared to hard-on-soft bearings. This study suggests that bearing surface materials and head size affect the amount of corrosion that is present at the modular junctions.

Does Taper Angle Clearance Influence Fretting and Corrosion Damage at the Head-Stem Interface? A Matched Cohort Retrieval Study

by Sevi B.Kocagöz, BS, Richard J. Underwood, PhD, Shiril Sivan, BE, Jeremy L. Gilbert, PhD, Daniel W. MacDonald, MS, JuddS. Day, PhD, and Steven M. Kurtz, PhD

Abstract

Previous studies have speculated that modular taper design may have an effect on corrosion and material loss at the taper surfaces. We present a novel method to measure taper angle for retrieved femoral head taper and stem trunnions using a roundness machine (Talyrond 585, Taylor Hobson, UK).We also investigated the relationship between taper angle clearance and visual fretting-corrosion score at the taper-trunnion junction using a matched cohort study of 50 ceramic and 50 metal head-stem pairs. In this study, no correlation was observed between the taper angle clearance and the visual fretting-corrosion scores in either the ceramic or the metal cohorts.

  • Fretting and Corrosion at Modular Junctions

    Can ceramics address this clinical issue?

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