Does immediate weight-bearing following intramedullary tibial nailing affect union rates? The results from a single UK trauma unit

Introduction Extra-articular diaphyseal tibial fractures are a common injury and are often treated with intramedullary nailing (IMN). Weight-bearing (WB) of simple tibial fractures treated with an IMN immediately as pain allows is now standard practice. Our aim was to assess the impact of varied WB on fracture union following IMN of diaphyseal tibia fractures. Methods We conducted a retrospective cohort study of tibial fractures treated with IMN in our department between 2012-2017. WB status was recorded in the post-operative note and subsequently reviewed in the patients’ follow-up appointments. Patients were divided in three groups; Group I: immediate full-WB, Group II: non-WB for 6 weeks and Group III: 2 weeks non-WB, 4 weeks increasing partial-WB and full-WB at 6 weeks. Radiographic union score for tibial fractures (RUST) of ≥10 at a painless fracture site was considered as evidence of fracture union. Results 92 patients with comparable pre-operative demographics [mean age 40 y (16-88)] were included. The median union time in weeks for each group was: Group I 17.3, Group II 21.7 and Group III 19.5 (F 1.09, p 0.34). Survival analysis and log rank test did not show any difference in union times between the three groups (x 2 1.1, p 0.57). 12 delayed unions were identified across all groups. Multiple logistic regression identified three factors that could increase the rate of delayed union – non-WB, smoking and IMN size 11/12 mm - however the results were not statistically significant. Conclusion Immediate post-operative WB does not adversely affect union time in statically locked IMNs. In fact, although our data show no statistically significant difference in fracture healing between the three groups, full WB seems to decrease overall time to union. In conclusion, we could suggest that full WB after IMN in patients with AO 42-A/B type fractures is safe practice.