[Oxalate-rare crystal disease in joints and kidneys]

We present the case of a 75-year-old patient who presented with recurrent arthralgia. Additional findings included chronic renal impairment of unknown cause and a history of partial small bowel resection. Arthrosonography raised suspicion of crystal arthropathy; however, no crystals were detected in the knee aspirate. Further investigation revealed previous findings of oxalate nephropathy, most likely as a result of increased reabsorption following abdominal surgery. Subsequently, Von Kossa staining of the aspirate confirmed oxalate arthropathy.