What are the Injures that Lead to Post-Traumatic Ankle Osteoarthritis? A Long-Term Retrospective Analysis of 533 Patients

CATEGORY: Ankle; Ankle Arthritis INTRODUCTION/PURPOSE: Ankle osteoarthritis (AO) is an incapacitating condition for patients and an important burden for medical assistance. It is well known that the vast majority of AO occurs as a sequela of previous trauma, however, it is currently unknown what types of injuries of the foot and ankle most commonly lead end-stage arthritis. The purpose of this study was to investigate the etiology of end-stage ankle osteoarthritis in all patients who underwent ankle fusion or replacement at a tertiary care center over a 20-year period. Our hypothesis was that the most common injury patterns would correspond to low-energy lesions. METHODS: The electronic medical record was queried using current procedural terminology (CPT) codes for ankle fusion or ankle replacement to identify all patients who underwent either of these procedures at a single tertiary academic center over a 20-year period. Etiologies were broadly grouped as Pilon/Plafond fracture, ankle fracture, talus fracture, tibia fracture, single or recurrent sprains, infection/septic joint, systemic disorder (Charcot arthropathy, rheumatoid arthritis, hemophilic arthropathy) and idiopathic/primary osteoarthritis. Each fracture pattern was then subclassified using commonly accepted classification systems by two independent observers in addition to the grade of arthritis at time of fusion or replacement. Reliability among readers was assessed by Kleiss kappa. Normative data were analyzed by ANOVA and comparison among groups and methods by Student's T- test. RESULTS: A total of 533 patients were included in this study. The initial injury patterns were broadly classified as: pilon/plafond (65), ankle (173), sprains (110), talus (17), tibia (22), tibio-talar dislocation without fracture (1). Other identified etiologies included rheumatoid arthritis (18), charcot arthropathy (11), progressive collapsing foot deformity (21), septic arthritis (5), and cavovarus (6). The average time interval between the initial injury and definitive treatment for end-stage arthritis was 558 days. Ankle fractures classified as 44C1 (14,1%), 44B3 (10.6%), 44B2 (9.3%) followed by pilon 43C3 (6.5%) and 43C1 (4.1%) were the most prevalent subclassification found in the fractures group. CONCLUSION: The main etiology for AO is secondary, due to trauma. History of ankle sprains and instability was found in 20.6%. Fractures corresponded to 54,6% of our cohort, ankle fractures producing most of these lesions. When considering the subtype of injury, ankle fractures with a 44C1 and a 44B3 classification were the more frequent presentation. These findings could support the argument that complex low-energy rotational traumas do not carry a benign course. Comprehension of the AO etiology scenario may guide prevention policies and specific primary treatment guidelines with the objective of diminishing disease impact on population and health care system.