Ankle Distraction Arthroplasty: A Survivorship Review and Meta-Analysis

Multiple treatments exist for ankle osteoarthritis. Ankle arthrodesis is the gold standard in late-stage osteoarthritis, but sacrifices range of motion and risks nonunion. Total ankle arthroplasty is typically reserved for low-demand patients as the long-term outcomes are poor. Ankle distraction arthroplasty is a joint sparing procedure which utilizes external fixator frame to unload the joint. This promotes chondral repair and improves function. This study aimed to organize clinical data and survivorship in published papers and direct further research efforts. Thirty-one publications were evaluated and 16 were included in the meta-analysis. The Modified Coleman Methodology Score was used to assess quality of the individual publications. Random effects models were used to estimate the failure risk after ankle distraction arthroplasty. Ankle Osteoarthritis Score (AOS), American Orthopedic Foot and Ankle Score (AOFAS), Van Valburg, and Visual Analog Scores (VAS) all improved postoperatively. Random effects model analysis revealed an overall failure ratio of 11% (95% CI: 7%-15%; p value ≤ .001; I² = 87.01%) after 46.68 ± 7.17 months follow up, 9% (95% CI: 5%-12%; p value≤0.001 I²=81.59%) with less than 5 years follow-up and 28% (95% CI: 16%-41%; p value≤0.001 I²=69.03%) for patients with more than 5 years follow-up. Ankle Distraction Arthroplasty has promising short to intermediate term outcomes which makes this a reasonable treatment option to delay joint sacrificing surgery. The selection of the optimal candidates and consistent technique would improve research and subsequently outcomes. Based on our meta-analysis, negative prognostic factors include female sex, obesity, ROM < 20°, leg muscle weakness, high activity level, low preoperative pain levels, higher preoperative clinical scores, inflammatory arthritis, septic arthritis, and deformity.