title: Metal sensitivities among TJA patients with post-operative pain: indications for multi-metal LTT testing.
abstract: Metal sensitivity testing is generally the diagnosis method of last resort for aseptic painful implants with elevated inflammatory responses. However, the relationship between implant-related pain and implant-debris-related metal sensitization remains incompletely understood. Although a sensitivity to nickel alone has been used as a general measure of metal allergy, it may lack the specificity to correlate sensitivity to specific implant metals and thus to select a biologically appropriate implant material. In this retrospective study, we report the incidence of pain and nickel sensitivity in patients with total joint arthroplasties (TJAs) referred for metal sensitivity testing (n=2018). We also correlated the degree of nickel hypersensitivity to implant pain levels (none, mild, moderate, and high, using a scale of 0-10) and the incidence of sensitivity to alternative implant metals in highly nickel-reactive subjects. Most patients (>79%) reported pain levels that were moderate to high regardless of implant age, whereas patients with severely painful TJAs had a statistically greater incidence of nickel sensitivity over the short-term post-operative period (≤4 years). Patients with moderate pain scores (4-7) and high pain scores (≥8) also exhibited significantly higher sensitivity to nickel compared to patients with no pain and no implant (controls) (p<0.05). Highly nickel-sensitive subjects (SI>8) also showed incidences of sensitization to alternative materials such as cobalt, chromium, or molybdenum (57%) or aluminum or vanadium alloy (52%). These data suggest that painful TJAs caused by metal sensitivity more likely occur relatively early in the post-operative period (≤4 years). The incidences of sensitivity to alternative implant metals in only a subset of nickel-reactive patients highlights the importance of testing for sensitization to all potential revision implant materials.
authors.affiliation: Orthopedic Analysis, LLC, Chicago, IL 60612; Department of Orthopedic Surgery, Rush University Medical Center, Chicago, IL 60612.
authors.forename: Marco S
authors.initials: MS
authors.lastname: Caicedo
authors.affiliation: Orthopedic Analysis, LLC, Chicago, IL 60612.
authors.forename: Edward
authors.initials: E
authors.lastname: Solver
authors.affiliation: Orthopedic Analysis, LLC, Chicago, IL 60612.
authors.forename: Latasha
authors.initials: L
authors.lastname: Coleman
authors.affiliation: Orthopedic Analysis, LLC, Department of Immunology, Department of Orthopedic Surgery, Rush University Medical Center, Chicago, IL 60612.
authors.forename: Nadim James
authors.initials: NJ
authors.lastname: Hallab
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000535:Aluminum / Q000276:immunology; D018771:Arthralgia / Q000209:etiology*; D019643:Arthroplasty, Replacement / Q000009:adverse effects / Q000295:instrumentation*; D002857:Chromium / Q000276:immunology; D003035:Cobalt / Q000276:immunology; D005260:Female; D006622:Hip Prosthesis / Q000009:adverse effects; D006801:Humans; D006968:Hypersensitivity, Delayed / Q000209:etiology / Q000276:immunology*; D007720:Knee Prosthesis / Q000009:adverse effects; D008297:Male; D061825:Metal-on-Metal Joint Prostheses / Q000009:adverse effects*; D008670:Metals / Q000009:adverse effects* / Q000276:immunology; D008875:Middle Aged; D008982:Molybdenum / Q000276:immunology; D009532:Nickel / Q000276:immunology*; D010147:Pain Measurement; D012189:Retrospective Studies; D013997:Time Factors; D014639:Vanadium / Q000276:immunology; D055815:Young Adult
chemical_list: D008670:Metals; D014639:Vanadium; D002857:Chromium; D003035:Cobalt; D009532:Nickel; D008982:Molybdenum; D000535:Aluminum