Biological Augmentation of Reamed Intramedullary Nailing for Aseptic Tibial Shaft Nonunion: An Exploratory Multicenter Retrospective Comparative Cohort Study

Background: Despite stable fixation, aseptic tibial shaft nonunion represents a severe orthopedic complication. Teriparatide and adipose-derived stem-cell augmentation have been proposed as biological supports, but comparative clinical evidence remains limited. This study explored whether adding adjuvant therapies to reamed intramedullary nailing was associated with faster healing than nailing alone. Methods: We retrospectively reviewed 43 adults with aseptic tibial shaft nonunion treated at three level I trauma centers between 2017 and 2020. Patients underwent reamed intramedullary nailing alone (n = 15), nailing plus teriparatide (n = 15), or nailing plus adipose-derived stem-cell augmentation (n = 13). Group allocation was nonrandom and based on contraindications and patient acceptance; results were therefore interpreted as exploratory. Outcomes included time to tricortical radiographic healing, pain, radiographic healing scores over time, complications, ASAMI classification, and SF-12. Results: Baseline demographic and fracture characteristics were comparable across groups. Time to tricortical radiographic healing was shorter in the teriparatide group (87.46 ± 6.34 days) and the adipose-derived stem-cell group (86.41 ± 5.67 days) than in the nailing-alone group (99.71 ± 4.29 days; p = 0.034). Pain, complication rates, ASAMI outcomes, and quality-of-life recovery did not differ significantly among groups at final follow-up. Conclusions: In this exploratory multicenter retrospective cohort, teriparatide and adipose-derived stem-cell augmentation were associated with shorter radiographic healing time after reamed intramedullary nailing for aseptic tibial shaft nonunion, but not with superior long-term functional outcomes. Because no comparator group treated with standard graft-based biological augmentation was included, the findings should be interpreted cautiously. Larger prospective studies or randomized controlled trials comparing these strategies with established graft-based approaches are needed to validate the present data.