No differences in union rates between grafts for subtalar arthrodesis

Purpose To investigate whether biologic adjuvants improve outcomes such as union rate and time to union of isolated subtalar arthrodesis. Methods The authors conducted a structured electronic literature search on December 29, 2025, using MEDLINE, EMBASE, and Cochrane. This review included prospective and retrospective comparative clinical studies comparing union rates following primary isolated subtalar arthrodesis, using biological adjuvants, which had a follow-up ≥ 6 months. Results The systematic search returned 929 records, of which 119 were duplicates, leaving 810 for screening. A total of 781 studies were excluded by examining their titles and/or abstracts, and a further 17 studies were excluded after a full-text review. This left 12 eligible studies. The pooled union rate using allografts was 92% (CI: 0.86–0.96), using autografts 97% (CI: 0.94–0.99), using synthetic/artificial grafts 96% (CI: 0.80–1.00), and without using any graft 96% (CI: 0.91–0.99), but the differences were not statistically significant. There was no statistically significant difference in time to union between allografts (13.7; CI: 12.8–14.6), autografts (14.0; CI: 13.3–14.6), synthetic/artificial grafts (12.7; CI: 12.0–13.4), and no grafts (13.7; CI: 11.8–15.7). Conclusion No statistically significant differences in union rates, time to union, and postoperative AOFAS of subtalar arthrodesis were found between autografts, allografts, synthetic/artificial grafts, and no grafts. For union rate, there was a tendency of lower fusion rates following allografts compared with the other types. The clinical relevance of these findings is that, as there was no difference in union rates, surgeons should take into account the donor-site morbidity and cost when considering the different graft types.