Pain in a chromium-allergic patient with total knee arthroplasty: disappearance of symptoms after revision with a special surface-coated TKA ­— a case report

Open Access This article is distributed under the terms of the Creative Commons Attribution Noncommercial License which permits any noncommercial use, distribution, and reproduction in any medium, provided the source is credited. DOI In 2005, a 60-year-old woman suffering from osteoarthritis received a total knee replacement (TKA) (e.motion, BBraun Aesculap, Tuttlingen, Germany) in another hospital. The prosthesis was implanted using antibiotic-loaded cement. Postoperatively, she suffered reduced mobility (E/F 0/10/60°) and her knee pain did not get better. In 2006, since the pain continued, a cemented retropatellar replacement was implanted. Radiological examination did not reveal any sign of a mechanical complication, but the pain still persisted and the patient was admitted to our hospital. Now, she complained of partly eczematous reactions (local itching, partial oozing, eczematous rashes), which appeared about half a year after the primary surgery (Figure 1). Blood counts including C-reactive protein test and bacteriological tests after joint aspiration virtually excluded a low-grade infection. A lymphocyte transformation test showed no increased values for metal ions (chromium, cobalt, nickel). Thus, in February 2009, the implant was replaced by a device that was geometrically identical to the initial prosthesis but was covered with an anti-allergic ZrN multilayer coating on the standard CoCr29Mo6 implant (Figure 2). It consists of 7 layers, a very hard shielding layer, ZrN, 5 intermediate layers which gradiently applied bridge the differences in hardness and residual stress between softer base material and hard top coating and a Cr bond coating which ensures adherence of the coating. The interfaces between the layers constitute an additional diffusion barrier against ions from the base material (Reich et al. 2010). The wound healed without complications and the eczema disappeared. Furthermore, at the last follow-up session in August 2010, 18 months after the revision, the mobility of the patient was excellent, with values of E/F 0/0/115°. The knee pain had disappeared. 3