Introduction: Oxidized Zirconium (OXINIUM™) is a metal alloy with a ceramic surface, utilized to increase the longevity of knee and hip implantations and reduce polyethylene wear. Polyethylene-based spacers are effective in infection control and prosthetic stability. Therefore, understanding the interactions between the polyethylene spacer and metallic counterparts is essential in surgical decision-making. Furthermore, understanding how patients may present when catastrophic failure of these components arises is imperative. Herein, we present a unique case of atraumatic OXINIUM™ wear in a middle-aged female after uneventful primary total knee arthroplasty (TKA), highlighting atypical clinical features and addressing the surgical management of this unexpected implant failure.
Case report: A 51-year-old African American female presented from an outside facility with persistent left knee pain after undergoing a TKA with a Smith and Nephew OXINIUM™ coated knee. The patient presented to the senior author's clinic with worsening symptoms 2-year postoperatively from her primary left TKA by another surgeon. After a thorough work-up which was essentially unremarkable-3 years from her initial surgery - the recommendation was made for surgical revision given clinical concern for instability. During the initial surgical approach, significant sparking of the tissue was noted on the use of electrocautery. Once the capsule was dissected, black synovial fluid with soft tissue involvement was noted. Intraoperative analysis of the polyethylene spacer revealed disintegration in the medial compartment with loss of the zirconium coating along the femoral component. There was no evidence of polyethylene spacer wear within the lateral compartment. The primary components were explanted and replaced with a nickel-free implant. Following revision, the patient reported complete resolution of her symptoms with improvement in active range of motion.
Conclusion: This case illustrates a unique presentation of atraumatic prosthetic surface coating failure after an uneventful primary TKA with well-aligned post-operative radiographs. Instability in the posterior stabilized total knee caused the polyethylene liner to come out of place, causing articulation of femoral and tibial components, creating the metal debris. Patients who present with persistent symptoms-of unknown etiology - after primary TKA should be considered for enhanced screenings and early surgical intervention.
Keywords: OXINIUM™; metallosis; prosthetic failure; total knee arthroplasty.
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