Skip to main content
Journal of Orthopaedics and Traumatology

Official Journal of the Italian Society of Orthopaedics and Traumatology

Download PDF

Blood metal ions after hybrid metal-on-polyethylene Exeter−Trident total hip replacement

Journal of Orthopaedics and Traumatology volume 17, pages 149–153 (2016)Cite this article

Abstract

Background

Metal-on-metal total hip replacements (THRs) with large femoral heads have been associated with elevated levels of cobalt (Co) and chromium (Cr), which have been attributed to high levels of wear at the articular surface. Our unit recently published data showing a significant increase in the mean levels of Co ions in patients with a 36-mm diameter femoral head with the metal-on-polyethylene Trident−Accolade system. The aim of this study is to assess the levels of Co and Cr in the Exeter−Trident hybrid system, as similar findings would raise concern over the V40 taper trunnion.

Materials and methods

The study included 83 patients (45 male and 38 female with a mean age of 75.6 years) who received Exeter−Trident hybrid metal-on-polyethylene THRs. The patients were then divided into two groups according to the diameter of the femoral head used—38 patients in the 28-mm group (control), and 45 in the 36-mm (experimental) group. Serum levels of blood Co and Cr were analysed for all recruited patients.

Results

In the control group (28-mm femoral head) all Co and Cr values were normal (under the abnormal threshold), as were the experimental group (36-mm femoral head). The data values were below <10 nmol and <40 nmol for Co and Cr, respectively.

Conclusion

Since the National Joint Registry (NJR) states that the Exeter femoral stem is the commonest cemented femoral stem prosthesis used in the UK, we found it imperative that these results are documented given the corresponding findings in the Trident−Accolade system in our previous study. This study provides relative reassurance that the issue does not lie with the V40 taper trunnion, but raises suspicion that the issue may be with the titanium Accolade stem with large diameter femoral heads.

Level of evidence III.

Introduction

Metal-on-metal (MoM) total hip replacements (THRs) with large femoral heads have been associated with elevated levels of cobalt (Co) and chromium (Cr) [1–7]. These elevated levels have been previously attributed to high levels of wear at the articular surface which have been linked to a causative factor in pseudotumour formation [8–12]. Other complications associated with increased metal ions include metal hypersensitivity, cardiomyopathy, aseptic lymphocyte-dominated vasculitis-associated lesions, and tubular necrosis [1–7]. There has been recent evidence in the literature on the possibility of the trunnion as a potential source of metal ions; however, much of this evidence is received from retrieval analysis of large head MoM THRs [13, 14].

All patients with large head MoM THRs had levels of Co and Cr ions measured, as advised by the Medicines and Healthcare products Regulatory Agency (MHRA) [15]. If these levels were above seven parts per billion (ppb; equivalent to Co 119 nmol/l and Cr 134.5 nmol/l) on two samples, collected 3 months apart, then clinical findings along with cross-sectional imaging should be used to consider revision surgery [15].

Co is a constituent of Vitamin B12 (cobalamin), a co-factor in haemoglobin metabolism [16] and Cr regulates the action of insulin, and both are important for general health. The pathological effects that have been reported in patients with raised levels of these ions following THR include visual disturbance, neurological impairment, auditory symptoms, cardiomyopathy, deep vein thrombosis, and pseudotumours [17–21]. There is a risk of contamination during the separation process when measuring levels of Co and Cr in serum of plasma. Therefore, whole blood collected in ethylenediaminetetraacetic acid or heparin is used [18].

In the tenth Annual Report of the National Joint Registry (NJR) for England and Wales, approximately 51 % of primary femoral stems in THRs in 2013 were reported as cemented fixation using stainless steel prosthesis. There has also been a steady rise in the use of large diameter (36 mm) femoral heads, from approximately 5 % of all heads to >20 % over the past 10 years [22]. This increase in the use of large diameter heads reflects the literature which states that larger heads reduce the rate of THR dislocation [23, 24]. In our unit, hybrid THR is undertaken using the Exeter−Trident system (Stryker Orthopaedics). Nationally, the Exeter femoral stem is the most commonly used cemented femoral stem in the UK. It is a polished, collarless tapered stem comprised of ‘Orthinox’, a proprietary stainless steel, which is issued with a V40 taper trunnion. The Trident acetabular component is a two-piece component with a hydroxyapatite-coated titanium alloy shell which is manufactured for press-fit following line-to-line reaming. The system utilises a unique locking mechanism providing a secure interface between the polyethylene (or ceramic) insert and the metallic shell [25].

There is little in the literature about the incidence of metallosis as a result of head–trunnion wear following metal-on-polyethylene (MoP) THR. Corrosion has been reported previously at metal junctions in THRs, and cases of pseudotumour formation attributed to metallosis in uncemented MoP THRs [26, 27].

Our unit has recently published data on a series of 69 patients who received uncemented Trident−Accolade metal on polyethylene THRs using 28- and 36-mm heads. This study showed a significant increase in the mean levels of Co ions in the blood of those with a 36-mm diameter femoral head compared to those with a 28-mm diameter head. The levels of Cr in the blood were normal in all patients. The clinical significance of this study to our unit was the suspension of use of 36-mm femoral heads for the Trident-Accolade system. The stimulus for carrying out that study was a case of severe pain following Trident−Accolade THR with a large head. This pain was secondary to severe corrosion at the head−trunnion interface leading to damage at the abductor insertion on the greater trochanter [28]. We then needed to see if this issue of raised metal ions particularly affects this combination of components in other commonly used prosthesis, such as the Exeter cemented femoral stem with the Trident acetabular cup, as this would imply an issue with V40 stem [28].

There has been no study of our magnitude directly comparing the levels of metal ions in the blood in small and large Exeter−Trident hybrid system MoP THRs. The aim of this study is to assess the levels of Co and Cr in the Exeter−Trident hybrid system as a follow-up study to see if there is a similar effect of raised metal ions using a combination of different head sizes with the V40 taper trunnion as seen in the Trident−Accolade THR.

Materials and methods

All patients who underwent Exeter−Trident hybrid MoP THRs in 2009 and 2010 were identified using the departmental database. Two patients had died and were excluding leaving 97 patients who were contacted by letter, which explained the purpose of the study and requested their participation. This required them to undergo blood Co and Cr ion level measurements . A total of 83 patients agreed to take part in our study. All 83 patients had undergone routine follow-up and all had satisfactory outcome at the last routine clinical review, which was confirmed by validated outcome measures. Ethical approval was obtained and implied informed consent was completed by all patients prior to enrolment.

Enclosed with the initial recruitment letter was an information leaflet regarding the blood test that was produced by the laboratory, and a pre-filled clinical chemistry request form [29].

The 83 patients involved in our study were separated into two groups according to the diameter of the femoral head which was used. A 28-mm head was used in 38 patients (twenty male and eighteen female with a mean age of 76.7 years), a 36-mm head in 45 (25 male and 20 female with a mean age 74.5 years). The patients with a 28-mm head were considered as a control group as we did not expect the levels of metal ions in their blood to be raised, as our previous study with the Trident−Accolade THR found the levels for this head size to be normal. Therefore, the patients with 36-mm femoral heads were considered the experimental group.

Venesection was performed either at our hospital or in primary care. The samples were analysed at an external (clinical pathology accredited) laboratory [28]. The patients treated in 2011 and 2012 were chosen for investigation as it was felt this was a sufficient period of time for the ‘wearing-in’ of the prosthesis. The measurement of the levels of metal ions in the blood occurred at a mean of 32 months after the THR.

Results were accessed from the hospital’s electronic record system and tabulated using an Excel spreadsheet (Microsoft, Redmond, WA, USA). Abnormal results were defined as Co levels >10 nmol/l (0.59 ppb) and Cr levels >40 nmol/l (>2.07 ppb), with normal ranges for adults without THR being below these thresholds. It should be noted that the results produced by the laboratory did not state the exact value if the result was <10 nmol/l and <40 mmol/l for Co and Cr, respectively.

To our knowledge the exact mechanism of wear at the trunnion has yet to be fully determined. It is likely that it is a combination of both frictional wear and corrosion. Certain factors such as the neck offset, head length and outer diameter of the acetabular components, all of which influence the lever arm and frictional torque applied to the trunnion, would benefit from their control. This is a limitation of our study.

The data was analysed using the SPSS software v20 (IBM, Armonk, NY, USA).

Results

In the control group (28-mm femoral head) all Co and Cr values were normal (under the abnormal threshold), as were the experimental group (36-mm femoral head) group (see Tables 1, 2).

Table 1 Mean and medium blood ion levels of cobalt
Full size table
Table 2 Mean and medium blood ion levels of chromium
Full size table

Discussion

In this small series, patients with a 36-mm diameter modular femoral head following an Exeter−Trident hybrid MoP THR did not have higher mean levels of Co than those with 28-mm heads. We found no increase in the mean levels of Cr ions in the blood of patients with an increased diameter femoral head. In fact, the values for both groups were within the normal range for both Co and Cr.

It has been documented in the literature that there is an issue of wear at the interface between the head and trunnion which has been associated with large head MoM THRs [30]. There is a potential source of metal ion release in all metal modular junctions, which means that it is unlikely that the bearing surface is the only contributor [31].

Certain factors that have been shown to increase polyethylene wear such as acetabular inclination angles of >45° and failure to restore femoral offset were not considered in our study [31–33]. Factors that have been previously shown to affect metal ion levels in patients with hip resurfacing and MOM THR such as gender and activity level were not controlled in our study [34].

The findings from the recent previous study carried out at our unit showed increased Co levels in patients with a 36-mm head in comparison to patients with a 28-mm head in Trident-Accolade MoP THRs [28]. These findings changed the practice in our unit with the cessation of usage of 36-mm femoral heads for that specific prosthesis. These findings also raised concern as to whether there was an issue with the V40 taper trunnion with larger heads. The findings from our current study provide relative reassurance that there is no issue with the V40 taper trunnion in the Exeter orthinox prosthesis [28]. It would seem that the results from both our studies suggest that the issue may lie with the titanium femoral stem in the Accolade system as opposed to the V40 taper trunnion, as the same trunnion with the orthinox (stainless steel proprietary) Exeter stem caused no increase in metal ion level regardless of size of the femoral head. We intentionally ensured that all the Exeter femoral stems used in our study were hybrid systems with the Trident acetabular cup and can therefore certify as much interrelation between the two studies as possible. These results have been shared with the manufacturer.

A previous randomised blinded clinical trial was carried out to assess polyethylene versus metal bearing surfaces in THR. This study included forty-one patients with identical femoral and acetabular components. Erythrocyte Co and Cr levels were measured and were significantly higher in patients with MOM articulations, with an average of 7.9-fold increase in erythrocyte Co and a 2.3-fold increase in erythrocyte Cr [35]. However, there were still detectable levels with the polyethylene inserts.

The effect of taper design on trunnionosis has been extensively evaluated. A comprehensive study looked at all hip prosthesis with a 28-mm plus zero length head over fourteen years with MoP implants giving a total of forty-four sets of retrieved implants, with six different taper designs. The Goldberg scale was used to score fretting and corrosion. This study showed no difference in patient age, body mass index, or length of implantation with regard to the trunnionosis. However, Taper design had a significant effect on corrosion at the base of the trunnion [36].

The results of this study are consistent with another study which only looked at twenty patients one year after surgery with the Exeter V40 stem with a variety of acetabular components. Whole blood Cr levels were within normal limits and only one patient exhibited mild elevation of serum Co [37]. The study carried out at our unit had a much larger series of patients and only looked at one acetabular component.

The clinical significance of the findings of our study remain uncertain, but as the NJR states that the Exeter femoral stem is the commonest cemented femoral stem prosthesis used in the UK, we found it imperative that these results are documented given the corresponding findings in the Trident−Accolade system in our previous study.

References

  1. Vendittoli PA, Roy A, Mottard S et al (2010) Metal ion release from bearing wear and corrosion with 28 mm and large-diameter metal-on-metal bearing articulations. J Bone Joint Surg Br 92-B:12–19

    Article  Google Scholar 

  2. Clarke MT, Lee PT, Arora A, Villar RN (2003) Levels of metal ions after small and large-diameter metal-on-metal hip arthroplasty. J Bone Joint Surg Br 85-B:913–917

    Google Scholar 

  3. Haddad FS, Thakrar RR, Hart AJ et al (2011) Metal-on metal bearings: the evidence so far. J Bone Joint Surg Br 93-B:572–579

    Article  Google Scholar 

  4. Langton DJ, Jameson SS, Joyce TJ et al (2010) Early failure of metal-on-metal bearings in hip resurfacing and large-diameter total hip replacement: a consequence of excess wear. J Bone Joint Surg Br 92-B:38–46

    Article  Google Scholar 

  5. Van Der Straeten C, Van Quickenborne D, De Roest B et al (2013) Metal ion levels from well-functioning Birmingham Hip Resurfacings decline significantly at 10 years. Bone Joint J 95-B:1332–1338

    Article  Google Scholar 

  6. Malek IA, King A, Sharma H et al (2012) The sensitivity, specificity and predictive values of raised plasma metal ion levels in the diagnosis of adverse reaction to metal debris in symptomatic patients with a metal-on-metal arthroplasty of the hip. J Bone Joint Surg Br 94-B:1045–1050

    Article  Google Scholar 

  7. Holland JP, Langton DJ, Hashmi M (2012) Ten-year clinical, radiological and metal ion analysis of the Birmingham Hip Resurfacing: from a single, non-designer surgeon. J Bone Joint Surg Br 94-B:471–476

    Article  Google Scholar 

  8. Davies AP, Willert HG, Campbell PA, Learmonth ID, Case CP (2005) An unusual lymphocytic perivascular infiltration in tissues around contemporary metal-on-metal joint replacements. J Bone Joint Surg Am 87-A:18–27

    Article  Google Scholar 

  9. Campbell P, Ebramsadeh E, Nelson S et al (2010) Histological features of pseudotumour-like tissues from metal-on-metal hips. Clin Orthop Relat Res 468:2321–2327

    Article  PubMed  PubMed Central  Google Scholar 

  10. Bosker BH, Ettema HB, Boomsma MF et al (2012) High incidence of pseudotumour formation after large-diameter metal-on-metal total hip replacement: a prospective cohort study. J Bone Joint Surg Br 94-B:755–761

    Article  Google Scholar 

  11. Canadian Arthroplasty Society (2013) The Canadian Arthroplasty Society’s experience with hip resurfacing arthroplasty: an analysis of 2773 hips. Bone Joint J 95-B:1045–1051

    Article  Google Scholar 

  12. Lombardi AV Jr, Barrack RL, Berend KR et al (2012) The Hip Society: algorithmic approach to diagnosis and management of metal-on-metal arthroplasty. J Bone Joint Surg Br 94-B(Suppl A):14–18

    Article  Google Scholar 

  13. Bolland BJ, Culliford DJ, Langton DJ et al (2011) High failure rates with a large-diameter hybrid metal-on-metal total hip replacement: clinical, radiological and retrieval analysis. J Bone Joint Surg Br 93-B:608–615

    Article  Google Scholar 

  14. Malviya A, Ramaskandhan JR, Bowman R et al (2011) What advantage is there to be gained using large modular metal-on-metal bearings in routine primary hip replacement? A preliminary report of a prospective randomised controlled trial. J Bone Joint Surg Br 93-B:1602–1609

    Article  Google Scholar 

  15. No authors listed. (2012): Medicines and health products regulatory agency. Management recommendations for patients with metal-on-metal hip replacement implants. http://www.mhra.gov.uk/home/groups/dts-bs/documents/medicaldevicealert/con155766.pdf. Accessed 20 Sept 2013

  16. Takahashi-Iñiguez T, García-Hernandez E, Arreguín-Espinosa R, Flores ME (2012) Role of vitamin B(12) on methylmalonyl-CoA mutase activity. J Zhejiang Univ Sci B 13:423–437

    Article  PubMed  PubMed Central  Google Scholar 

  17. Hummel M, Standl E, Schnell O (2007) Chromium in metabolic and cardiovascular disease. Horm Metab Res 39:743–751

    Article  CAS  PubMed  Google Scholar 

  18. Egan K, Di Cesare PE (1995) Intraoperative complications of revision hip arthroplasty using a fully porous-coated straight cobalt—chrome femoral stem. J Arthroplasty 10(Suppl 1):S45–S51

    Article  PubMed  Google Scholar 

  19. Shimmin A, Bare J, Back D (2005) Complications associated with hip resurfacing arthroplasty. Orthop Clin North Am 36:187–193

    Article  CAS  PubMed  Google Scholar 

  20. Gessner BD, Steck T, Woelber E, Tower SS (2015) A Systematic Review of Systemic Cobaltism after Wear or Corrosion of Chrome-Cobalt Hip Implants. J Patient Saf [Epub ahead of print]

  21. Steens W, von Foerster G, Katzer A (2006) Severe cobalt poisoning with loss of sight after ceramic-metal pairing in a hip: a case report. Acta Orthop 77:830–832

    Article  PubMed  Google Scholar 

  22. Porter M, Borroff, Gregg et al. (2013) National Joint Registry for England and Wales 10th annual report. www.njrcentre.org.uk

  23. Jameson SS, Lees D, James P et al (2011) Lower rates of dislocation with increased femoral head size after primary total hip replacement: a five-year analysis of NHS patients in England. J Bone Joint Surg Br 93-B:876–880

    Article  Google Scholar 

  24. Bistolfi A, Crova M, Rosso F et al (2011) Dislocation rate after hip arthroplasty within the first postoperative year: 36 vs 28 mm femoral heads. Hip Int 21:559–564

    Article  PubMed  Google Scholar 

  25. Williams HD, Browne G, Gie G, Ling R, Timperley A, Wendover N (2002) The Exeter universal cemented femoral component at 8–12 years. J Bone Joint Surg Br 84-B:324–334

    Article  Google Scholar 

  26. Svensson O, Mathiesen EB, Reinholt FP, Blomgren G (1988) Formation of a fulminant soft-tissue pseudotumour after uncemented hip arthroplasty: a case report. J Bone Joint Surg Am 70-A:1238–1242

    Google Scholar 

  27. Cooper HJ, Valle Della CJ, Berger RA, Tetreault M, Paprosky WG, Sporer SM et al (2012) Corrosion at the head-neck taper as a cause for adverse local tissue reactions after total hip arthroplasty. J Bone Joint Surg Am 94(18):1655–1661

    PubMed  Google Scholar 

  28. Craig P, Bancroft G, Burton A, Collier S, Shaylor P, Sinha A (2014) Raised levels of metal ions in the blood in patients who have undergone uncemented metal-on-polyethylene Trident-Accolade total hip replacement. Bone Joint J 96:43–47

    Article  PubMed  Google Scholar 

  29. Daniel J, Ziaee H, Pradhan C, Pynsent PB, McMinn DJW (2007) Blood and urine metal ion levels in young and active patients after Birmingham hip resurfacing arthroplasty. Four-year results of a prospective longitudinal study. J Bone Joint Surg Br 89(2):169–173

    Article  CAS  PubMed  Google Scholar 

  30. Hexter A, Panagiotidou A, Singh J, Skinner J, Hart A (2013) Corrosion at the head: trunnion taper interface in large diameter head metal on metal total hip arthroplasty: a comparison of manufacturers. Bone Joint J 95-B(Suppl 12):3

    Google Scholar 

  31. Little NJ, Busch CA, Gallagher JA, Rorabeck CH, Bourne RB (2009) Acetabular poly-ethylene wear and acetabular inclination and femoral offset. Clin Orthop Relat Res 67:2895–2900

    Article  Google Scholar 

  32. Devane PA, Horne JG (1999) Assessment of polyethylene wear in total hip replacement. Clin Orthop Relat Res 369:59–72

    Article  PubMed  Google Scholar 

  33. Sakalkale DP, Sharkey PF, Eng K, Hozack WJ, Rothman RH (2001) Effect of femoral offset on polyethylene wear in total hip replacement. Clin Orthop Relat Res 388:125–134

    Article  PubMed  Google Scholar 

  34. Heisel C, Silva M, Skipor AK, Jacobs JJ, Schmalzried TP (2005) The relationship between activity and ions in patients with metal-on-metal bearing hip prostheses. J Bone Joint Surg Am 87-A:781–787

    Article  Google Scholar 

  35. MacDonald SJ, McCalden RW, Chess DG, Bourne RB, Rorabeck CH, Cleland D, Leung F (2003) Metal-on-metal versus polyethylene in hip arthroplasty: a randomized clinical trial. Clin Orthop Relat Res 406:282–296

    Article  PubMed  Google Scholar 

  36. Tan SC, Teeter MG, Del Balso C, Howard JL, Lanting BA (2015) Effect of taper design on trunnionosis in metal on polyethylene total hip arthroplasty. J Arthroplast. doi:10.1016/j.arth.2015.02.031

    Google Scholar 

  37. Vijaysegaran P, Whitehouse SL, Bijoor M, English H, Crawford RW (2014) Metal ion levels post primary unilateral Exeter total hip arthroplasty. Hip Int 24(2):144–148

    Article  PubMed  Google Scholar 

Download references

Author information

Authors and Affiliations

  1. Robert Jones Orthopaedic Hospital, Oswestry, UK

    Rohit Singh, Gopikanthan Manoharan & Pete Craig

  2. Mid Staffordshire foundation trust, Stafford, England, UK

    Simon Collier, Phillip Shaylor & Ashok Sinha

Authors
  1. Rohit Singh
    View author publications

    You can also search for this author in PubMed Google Scholar

  2. Gopikanthan Manoharan
    View author publications

    You can also search for this author in PubMed Google Scholar

  3. Pete Craig
    View author publications

    You can also search for this author in PubMed Google Scholar

  4. Simon Collier
    View author publications

    You can also search for this author in PubMed Google Scholar

  5. Phillip Shaylor
    View author publications

    You can also search for this author in PubMed Google Scholar

  6. Ashok Sinha
    View author publications

    You can also search for this author in PubMed Google Scholar

Corresponding author

Correspondence to Rohit Singh.

Ethics declarations

Ethical standards

This study conforms to the last version of the Declaration of Helsinki, was approved by the Ethical Committee, and implied informed consent from all the patients prior to their enrolment.

Conflict of interest

The authors whose names are listed on this paper certify that they have no affiliations with or involvement in any organisation or entity with any financial interest (such as honoraria, educational grants, participation in speakers’ bureaus, membership, employment, consultancies, stock ownership, or other equity interest, and expert testimony or patent-licensing arrangements), or non-financial interest (such as personal or professional relationships, affiliations, knowledge or beliefs) in the subject matter or materials discussed in this manuscript.

Rights and permissions

Open Access This article is distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made.

Reprints and permissions

About this article

Check for updates. Verify currency and authenticity via CrossMark

Cite this article

Singh, R., Manoharan, G., Craig, P. et al. Blood metal ions after hybrid metal-on-polyethylene Exeter−Trident total hip replacement . J Orthopaed Traumatol 17, 149–153 (2016). https://doi.org/10.1007/s10195-015-0369-4

Download citation

  • Received:

  • Accepted:

  • Published:

  • Issue Date:

  • DOI: https://doi.org/10.1007/s10195-015-0369-4

Keywords