Analysis of risk factors for failure of arthroscopic ankle fusion in a series of 52 ankles.

BACKGROUND: The purpose of this retrospective study is to analyze the effect of different variables on union rate and functional outcome in patients who underwent arthroscopic ankle fusion for end-stage arthritis of ankle. METHODS: Clinical records and radiographs were reviewed to evaluate the variables that could predispose patients to non-union and poor functional outcome. Union and functional outcomes were correlated with different variables. RESULTS: Fifty patients had arthroscopic ankle fusion on 52 ankles. The mean age at the time of surgery was 59.4 (27-80) years and mean length of follow up was 32.1 (8-78) months. Forty-eight out of 52 ankles (92.3%) achieved radiographic and clinical union. The average time to fusion was 12.2 (8-28) weeks. The time taken for union was significantly higher in smokers as compared to non-smokers (p<0.001). All the patients in this series who had non-union shared one common factor - neuromuscular imbalance. Age, gender, smoking, diabetes, steroid, bisphosphonates, neuropathy, frontal and sagittal plane alignment and tibial-axis-to-talus (T:T) ratio did not significantly affect the union rate and functional outcome. CONCLUSION: Smokers should refrain from smoking before surgery and patients with neuromuscular problems may require more rigid fixation and a longer period of immobilization to achieve more consistent union rates.