Factors associated with improvement in ankle dorsiflexion after transfibular total ankle arthroplasty

BACKGROUND: While transfibular total ankle arthroplasty (TAA) demonstrates favorable short-term outcomes, factors influencing postoperative ankle dorsiflexion remain underexplored. This is the first study aimed to identify factors influencing dorsiflexion range of motion after transfibular TAA. METHODS: Forty-nine patients undergoing transfibular TAA were classified into dorsiflexion-improved (DF-improved) group (≥5°,n = 26) and dorsiflexion-non-improved (DF-non-improved) group (<5°, n = 23). Radiographic parameters, residual medial tibial osteophytes, and Achilles tendon lengthening were evaluated. RESULTS: The DF-improved group had smaller anterior talar implant depth (3.1 ± 2.0 mm vs. 5.5 ± 1.7 mm), greater γ angle (17.4 ± 4.3°vs. 14.4 ± 5.1°), smaller proportion of postoperative residual medial tibial osteophyte (2 vs. 10), and more Achilles tendon lengthening than the DF-non-improved group (9 vs. 2). CONCLUSIONS: Close consideration of the depth and angle of talar implant placement, meticulous osteophyte resection of medial tibia, and Achilles tendon lengthening may improve the postoperative dorsiflexion following transfibular TAA. LEVELS OF EVIDENCE: Level III case-control study (retrospective comparative study).