Mid Term 5-Year Follow Up of a Novel Algorithm for Non-Operative Weber B Ankle Fractures

Abstract

Category: Ankle, Ankle Arthritis, Trauma Introduction/Purpose: It is important to understand which isolated fibular fractures require surgical intervention. Several different radiographic guidelines have been used to interpret and predict stability of the injured ankle. Holmes et al previously described a novel algorithm used to assess stability and the ability to treat the stable injuries non-operatively. The one year results demonstrated favorable outcomes of these non-operative patients, however there is a question about the durability of these results and whether these patients developed post-traumatic degenerative changes over mid to long term follow up. Methods: An observational study based on a previous cohort of 51 patients studied from 2010 to 2013 with isolated Weber B ankle fractures was performed. These were defined as stable at the time of injury when the medial clear space (MCS) was less than 7 mm on the initial gravity stress radiographs along with a normal mortise relationship on weight bearing radiographs. 27 patients that were treated non-surgically, were brought back for a mid-term follow up with a mean of 6.8 years. American Orthopaedic Foot & Ankle Society (AOFAS) Hindfoot scores, Olerud-Molander Ankle (OMA) Score, and visual analog scale (VAS) pain score were collected in accordance with the prior study. Patient Reported Outcome Measurement Information System (PROMIS) scores were also collected including lower extremity, physical function, depression, and pain interference. Standing bilateral ankle radiographs were obtained, and assessed for MCS widening, and ankle arthritis using the Kellgren-Lawrence grading scale. Results: Average functional score results were (in comparison to 1-year outcomes): AOFAS Hindfoot, 95.7 (93.2); OMA Score, 95.2 (91.0); and visual analog scale pain score, 0.24 (0.57). Using a Wilcox Signed Ranks Test, there was a statistically significant increase in 5-year AOFAS Hindfoot scores as compared to 1-year scores in those same patients (p=0.005) There was no evidence of significant post-traumatic osteoarthritis based on the Kellgren-Lawrence grading scale. Conclusion: The previously described, novel at the time, algorithm for assessing stability of isolated Weber B ankle fractures and nonsurgical treatment with protected weight bearing has shown to produce excellent results for mid-term follow up with an average of 6.8 years. Additionally, these patients are not at increased risk for rapid progression of post-traumatic osteoarthritis. This further supports initial weight bearing radiographs as a reasonable assessment of ankle stability and validates the aforementioned algorithm as a safe and cost-effective functional treatment regimen.