Abstract
Background: Heterotopic ossification (HO) is a frequent radiographic finding after total ankle arthroplasty (TAA), but its clinical relevance, diagnostic criteria, and prognostic implications remain uncertain. This systematic review summarizes current evidence on HO incidence, distribution, severity, risk factors, clinical impact, and diagnostic/prognostic value to inform surgical decision-making regarding approach, implant design, and revision strategies. Methods: A systematic review was conducted according to PRISMA guidelines using PubMed, Web of Science, and Scopus databases and the following search string "heterotopic ossification" AND "ankle" (February 2015-February 2025). Twenty-two studies were included, most of which were retrospective and varied in methodological quality. Data were extracted on HO incidence, severity, clinical relevance, and factors associated with diagnosis and management. Results: HO incidence varied widely across studies. No significant associations were found between HO and surgical variables such as approach (all studies used the anterior approach) or coronal alignment. HO presence did not consistently correlate with reduced postoperative range of motion and radiographic follow-up duration. Implant design appeared to influence anatomical distribution in some comparative studies, though without statistical significance. Reoperations specifically for HO excision were rare and mainly performed for mechanical complications (impingement or osteolysis) rather than HO severity itself. Conclusions: Although HO is a frequent finding after TAA, its clinical impact appears limited and largely unpredictable. Diagnostic tools are currently limited to conventional radiography, and no reliable prognostic markers exist. Further high-quality studies are needed to define standardized diagnostic criteria and clarify the prognostic role of HO in long-term outcomes.