Metal sensitivity toElektra�prostheses – two casesfrom ametal on metalimplant for hand jointreplacement

Contact Dermatitis 2009: 60: 298

Emma Smith, Anisha J Mehta andBarry N Statham

Department of Dermatology, SingletonHospital, Swansea, UK

Key words: allergy; cobalt; elektra prosthesis;metacarpal joint replacement; metal sensiti-vity; nickel; trapezio-carpo-metacarpal jointreplacement.

Metal sensitivity relevant to jointprostheses is a controversial area withfew reports of sensitivity causing fail-ure. We present two convincing casesof metal on metal implants with metalallergy histories where prosthesisremoval resolved symptoms.

Case 1

A 51-year-old female was referred byorthopaedic surgeons for patch test-ing. One year earlier, she had under-gone a right trapezio-metacarpaljoint arthroplasty with an Elektra�[Small Bone Innovations Interna-tional� (formerly Fixano�) ZA, LesBruyeres – BP 28, Peronnas, France)cementless metal on metal prosthesis.Four months postoperatively shedeveloped swelling and constant painat the site but no rash. She reportedprevious nickel allergy.

The joint was swollen but not ery-thematous. Active but not passivemovements were painful. There wasno evidence of infection, looseningor dislocation; bone scintigraphyrevealed localized increased uptake.

She was patch tested to a modifiedEuropean baseline series and methac-rylate series with a 3þ positive reac-tion (ICDRG criteria) to both cobaltchloride and nickel sulphate at D4.

Given the clinical picture andstrongly positive patch test, the pros-thesis was removed and revised to

a pyro-carbon spacer. Five monthslater, the patient was pain-free havingregained good hand function.

Case 2

A 52-year-old female referred byorthopaedic surgeons had intermittentleft thumb pain and swelling followingprosthesis insertion. Eight monthspreviously, she had undergone anElektra� carpo-metocarpal joint re-placement; symptomsstarted2 monthslater. There were no signs of infectionor erythema, she had good range ofmovement. She was atopic and notedan intolerance to metal jewellery.

There were concerns because ofplans for a second joint replacementin the right hand. She was tested tomodified European baseline serieswith a 3þ positive reaction to cobaltchloride only at D4. Her prosthesiswas taken out and within 2 monthsshe was symptom-free.

The histories and rapid, sustainedresponses to removal make allergy thelikely cause of symptoms in both cases.

Discussion

Metal allergy has been reported toknee and more often hip replace-ments. Postoperative patch testingby Benson et al. (1) demonstratedmetal allergy in 28% of subjects withmetal on metal prostheses but associ-ated it only with loosening. The com-monest allergen was cobalt followedby nickel then chromate. The preva-lence of metal allergy in studies ofprosthetic loosening varies from13% to 74% (2).

The single study looking at sensi-tivity causing metal-on-metal hipprosthesis failure suggested an associa-tion but used too few subjects to con-firm this (3). Reed et al. (4) recentlyconcluded that preoperative testingcould beof use in guidingdevice choice.

Elektra� trapezio-metacarpal im-plants made by Small Bone Innova-tions International� are metal onmetal, containing cobalt, chromiumand titanium. The alloy is similar toearly hip replacements with modifica-tion to improve wear resistance ratherthan reduce hypersensitivity, which isseen less in metal on plastic joints.

Regnard (5) reported results of hisfirst 100 Elektra� prostheses withaverage follow up of 54 months. Onlyone experienced failure due to nickelallergy, presenting as non-infectious

inflammation. Small Bone Innova-tions International� advise of risks ontheir packaging but have not receivedother reports of symptomatic allergy.The two cases reported here arefrom seventy Elektra� proceduresperformed in our orthopaedics depart-ment.These findings suggest sensitivitycan cause joint device failure requiringrevision in some patients with knownmetal allergy. Dermatologists shouldbe aware of this group and have a lowthreshold for patch testing them.

References

1. Benson M K D, Goodwin P G, Brost-off J. Metal sensitivity in patients withjoint replacement. Br Med J 1975; 4:374–375

2. Gawkrodger D J. Metal sensitivitiesand orthopaedic implants revisited:the potential for metal allergy with thenew metal-on-metal joint prostheses.Br J Dermatol 2003;148:1089–1093.

3. Anthony F, Dudley W, Field R,Holden C. Metal allergy resurfaces infailed hip endoprostheses. Br J Derma-tology 2001; 145 (Suppl. 59): 48.

4. Reed K B, Davie M D, Nakamura Ket al. Retrospective evaluation of patchtesting before or after metal deviceimplantation. Arch Dermatol 2008;144: 1042–2042.

5. Regnard P J. Electra trapezio meta-carpal prosthesis: results of the first100 cases. J Hand Surg 2006; 31:621–628.

Address:Dr E SmithDermatology Department,Singleton HospitalSketty Lane,Swansea SA2 8QAUKTel: 0044 1792 206816Fax: 0044 1792 285330e-mail: dremmasmith@doctors.org.uk

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