Steroid or pseudogout? Analysis of white deposits in tissues during surgery.

Introduction: Pseudogout is characterized by the deposition of calcium pyrophosphate crystals in the pericellular matrix of chondrocytes. Pseudogout flares can present similar to gout, osteoarthritis, septic arthritis, or prosthetic joint infection, potentially complicating post-surgical outcomes. With a high prevalence among patients undergoing arthroplasty, appropriate awareness is essential to mitigate misdiagnosis and inappropriate treatment. This study reviews a series of eight patients in whom white deposits are identified intraoperatively and seeks to guide identification, patient education, and future treatment for pseudogout.

Methods: Patients undergoing surgical intervention were assessed for the presence of an intraarticular white substance. When the substance was identified, a sample was sent for assessment by a pathologist. The patients' age, sex, pertinent history, surgery, site of biopsy, and pathologist findings were documented.

Results: Of the eight patients included in the study, the average age was 67.9 years (range 62-75). Five (62.5%) were male and three (37.5%) were female. Six (75%) were found to have CPPD crystals. Out of these six, one had a steroid injection 5 months prior and another 7 months prior. One patient who had a steroid injection 4 months prior to surgery had a scant amount of white substance that was identified as "acellular material" by the pathologist. Only a single patient of these six had a standing diagnosis of pseudogout prior to surgery. Intraoperatively, the white substances were visually similar in all cases.

Conclusions: There is a high prevalence of pseudogout in patients over the age of 65 and with concurrent arthritis. Presentation of pseudogout can range from asymptomatic to mimicking septic arthritis. Unidentified white substances noted intraoperatively should be sent to pathology for identification. In patients with pseudogout, it is important to educate the patient and consider prophylactic treatment to minimize risk of recurrence and damage to other joints.