Methods
allergic, allergy, hypersensitivities, TKA, allergies
-20, ALLERGY, HYPERSENSITIVITIES, ALLERGIES
After institutional review board approval (IRB 00001473, IORG 00001076, registered at Office for Human Research Protection, EK 101,032,016) a randomized-controlled trial was conducted. The study protocol was registered prior to enrollment in the US National Institutes of Health’s database (Patients scheduled for an unconstrained TKA without self-reported hypersensitivities against implant materials and without any existing metal implants were eligible to participate. After informed consent, a total of 80 patients were randomized using a software algorithm to receive a standard or coated TKA (Vega or Vega AS, B.Braun Aesculap, Tuttlingen, Germany). In one patient surgery was delayed due to medical problems and three patients needed a higher constraint during surgery. Therefore, a total of 76 patients was included in this study. An additional group including all patients with diagnosed allergies against one or more implant metals who presented during the study enrollment period was established (n = 8). Three patients of the allergy group were allergic to nickel only. Four patients had an allergy against nickel and cobalt and one patient presented with an allergy against nickel and palladium. These patients received the coated implant due to local guidelines (Fig. Both implants consisted of a CoCrMo-alloy (ISO 5832-4). The coated TKA had an additional multilayer coating system (Advanced Surface, AS) which was applied on the CoCrMo knee implants using a physical vapour deposition method in 7 layers with a gradient change in stiffness between the TKA body and the final layer with a total thickness of about 4 μm [Patients were seen by a study nurse prior to, 3 months, 1 year and 3 years after surgery. Knee Function (Oxford Knee Score, [OKS], Knee Society Score, [KSS]) and health-related quality of life (EQ-5D)) was assessed [
Flowchart of study patients enrollment and follow-up. Valid blood cytokine patterns were available from 74 patients from cryopreserved serum samples, which were stored at -20 °C. The blinded samples were assessed for the presence and concentration of 7cytokines by a multiplex cytometric bead assay (CBA; BD Biosciences, Heidelberg, Germany) via flow cytometry using a FACS canto (BD Biosciences, Heidelberg, Germany) [