KOA Conference Eldoret 2016

Hypersensitivity Reactions To Mettallic Implants: A case report and review of the Literature Vincent M Mutiso Swafiya S Busaidy

Implants Commonly used in Orthopaedics eg: Arthroplasty Fractures Also used in Other specialties eg; cardiology dentistry gynaecology

Epidemiology Dermal hypersensitivity to metals affects % of population Despite this it rarely presents clinically

Pathophysiology Metal implant in the body undergoes corrosion This electrochemical reaction results in the formation of metal ions These activate the immune system to produce complexes with endogenous proteins These act as Allergens ( Antigens)

Clinical Presentation Usually subtle Can be severe Large areas of the body parts or regions Myolysis

Management Good History ( good index of suspicion) Examination Investigations - Patch test - Lymphocyte transformation testing (label with radioactive thymidine marker) - ? ELISA

management Usually subtle and often treated Conservatively May need to remove implants

case Middle aged lady fracture ankle with no history of allergies ORIF with stainless steel metallic implants Presented four weeks later with severe dermatitis necessitating admission to hospital Patch testing was positive for Nickel Conservative treatment including antihistamines Discharged after one week

Right ankle- almost resolved

Relevant lab results Normal Hb ESR CRP WBC (lymphocyte count upper normal)

Clinically NOT fluctuant or tender Only slightly warm to the touch

Discussion Although epidemiological 10 – 15% prevalence, relatively rare presentation Unpredictable and poorly understood Antigen presenting cells include lymphocytes, Langerhans cells, dendritic cells, parenchymal tissue cells

implants Medical grade Stainless steel contains –Nickel 13 – 15.5% Chromium 17 – 19% Molybdenum 2- 4% Nickel and Chromium cross react

Arthroplasty Prevalence of sensitivity with well functioning implants is 25% ( X2 of pop) Prevalence in poorly functioning/failed implants is 60% ( X6 of pop) This association does not prove a causal effect Testing can trigger a reaction Log stay implants may inducemetal tolerance. Metal to Metal Joint replacements presently generating a lot of interest

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