Ballooning Periprosthetic Osteolysis Related to Crystalline Arthropathies Following Total Ankle Arthroplasty: A Case Series

Abstract

Category: Ankle Arthritis; Basic Sciences/Biologics Introduction/Purpose: From 2009-2019, there has been a 120% increase in the incidence of total ankle arthroplasty (TAA) in the United States. With the rise in primary TAA, future increases in revision TAA cases is anticipated. Aseptic loosening with periprosthetic osteolysis continues to account for a significant number of revisions. While several factors may contribute to the pathophysiology of osteolysis, an underlying inflammatory response surrounding TAA implants may play a primary role. It is well known that monosodium urate (gout) and calcium-pyrophosphate (pseudo-gout) crystals evoke a highly inflammatory response and may involve the foot and ankle joints. However, the effect of these conditions following TAA has not yet been reported. We present a small case series of patients with ballooning osteolysis following TAA with confirmed crystalline arthropathy. Methods: This is a retrospective study from a single academic institution looking at patients who underwent TAA revision surgery for periprosthetic osteolysis and concern for aseptic loosening. Revision surgeries were performed by three orthopedic foot and ankle fellowship trained surgeons. Case characteristics, including pre-operative imaging, clinical presentations, intra-operative findings and surgical treatments performed were analyzed and presented in this small case series. Results: We report 5 patients whom underwent revision surgery for ballooning periprosthetic osteolysis following TAA. Intra- operative pathology samples from periprosthetic cysts returned positive for monosodium urate (MSU) or calcium pyrophosphate (CPP) crystalline deposition (1 MSU and 4 CPP) in all 5 patients. Final intra-operative cultures were all negative for infection. Upon gross intra-operative inspection, all polyethylene liners were considered to be normal without abnormal wear characteristics. Periprosthetic cysts were isolated to the tibial component in 2 patients and involved both the tibial and talar components in 3 patients. Staged TAA revision was performed in 2 patients. Bone cyst curettage, bone grafting and polyethylene liner exchange was performed in 3 patients. Conclusion: Periprosthetic osteolysis is a known complication following TAA and often leads to implant loosening, functional disability and subsequent revision surgery. An objective strategy for management of this condition has not been agreed upon amongst orthopedic foot and ankle surgeons, as uncertainty remains surrounding the pathophysiology of osteolysis in TAA. To our knowledge, we are the first to describe a small case series of patients with crystalline arthropathy as a potential cause for periprosthetic osteolysis following TAA. Future prospective studies are warranted to better elucidate this potential cause of TAA failure.