Crystal Arthropathy following Knee Arthroplasty: A Review of the Literature

Abstract

Introduction: Crystal arthropathy is a well-established differential diagnosis in suspected native joint septic arthritis however it is often overlooked in the setting of a prosthetic joint.

Objectives: In the current review we evaluate all of the available literature on the subject of crystal arthropathy in the setting of prosthetic knees, in order to determine the patterns of presentation, diagnostic protocols and management of such cases.

Features of review: A total of 30 individual reported cases of peri-prosthetic crystal arthropathy affecting the knee joint, were identified for inclusion. Of these, 17 cases reported a confirmed diagnosis of gout, with 13 concluding a diagnosis of pseudogout. Inflammatory and infectious markers were usually raised or borderline high across both groups of patients, with the following combined mean values; ESR: 65.5mm, CRP: 95.6ml/L and Wcc: 10.8*10(9)/L for gout and pseudogout respectively. There were 4 cases (13.3%) of concomitant infection and crystal arthropathy. Management varied widely across cases, with gout patients commonly undergoing invasive surgical washout (59%), and pseudogout cases largely managed conservatively (71%).

Conclusions: Correctly diagnosing crystal arthropathy in a prosthetic joint can result in the avoidance of invasive surgical intervention. We would advocate the use of routine crystal microscopy in the diagnostic process of all suspected peri-prosthetic infections. A high degree of caution should be taken however in view of the possibility of concomitant prosthetic crystal arthropathy and septic arthritis.