Injury - 2026-04-01 - Journal Article
Association between time to weight bearing and rates of nonunion, delayed union, and malunion after intramedullary nailing of tibial shaft fractures.
Moon TJ, Adelstein JM, Furdock RJ, Nedder VJ, Dorney I, Swetz AM, Ochenjele G, Wetzel RJ, Sontich JK, Napora JK, Romeo NM
Topics
Key Takeaway
Each week of delay in weight bearing as tolerated after tibial shaft IMN independently increases nonunion odds by 7% (OR 1.07, 95% CI 1.03–1.12), with mean time to WBAT 8.3 weeks in union versus 13.7 weeks in nonunion cases.
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Summary
This study asked whether time to WBAT after tibial shaft IMN predicts nonunion, delayed union, or malunion in a retrospective cohort of 433 fractures across two Level 1 trauma centers (2010–2021). Binary logistic regression identified delayed WBAT as an independent predictor of nonunion (OR 1.07/week, p<0.001) and delayed union (10.0 vs. 7.8 weeks, p<0.001). No association was found between time to WBAT and tibial deformity (p=0.9), supporting early mobilization without alignment risk.
Key Limitation
Confounding by indication is the critical flaw: the decision to delay WBAT was surgeon-directed and likely correlated with fracture instability, soft tissue compromise, and patient compliance—variables not fully controlled in the regression model.
Original Abstract
INTRODUCTION
Intermedullary nailing (IMN) is the gold standard for tibial shaft fractures in adults with the goal of allowing early weight bearing. The purpose of this study was to determine the association between time to weight bearing as tolerated (WBAT) after tibial shaft IMN fixation and fracture nonunion, delayed union, and tibial deformity at final follow-up.
METHODS
A retrospective cohort of patients who sustained extra-articular tibial shaft fractures treated with IMN at two level 1 trauma centers were collected from 2010 to 2021. A minimum follow-up of six months was required unless there was presence of clinical and radiographic union prior to six months. Time to allowance of WBAT was the primary independent variable and primary outcomes included nonunion, delayed union greater than 6 months, and tibial deformity were assessed.
RESULTS
433 tibia fractures met inclusion criteria. Mean age was 44 years. 260 (60 %) patients were male. 194 (45 %) patients were current tobacco users. 255 (59 %) patients sustained a high energy fracture mechanism. 60 (14 %) fractures were classified as AO/OTA 42-C and 181 (42 %) fractures were open. Nonunion rate was 14 % (61/433). Mean time to WBAT was 8.3 weeks in the union group and 13.7 weeks in the nonunion group (p < 0.001). Binary logistic regression demonstrated time to WBAT as an independent predictor of nonunion (OR = 1.07 per week delay, 95 % CI 1.03-1.12, p < 0.001). Time to WBAT was also associated with delayed union (10.0 weeks delayed union versus 7.8 weeks early union, p < 0.001). There was no association between time to WBAT and tibial deformity (8.8 weeks deformity versus 9.0 weeks no deformity, p = 0.9).
CONCLUSION
Earlier time to initiation of WBAT is associated with decreased nonunion and decreased delayed union after IMN of tibial shaft fractures without increased risk of malunion. Providers may consider allowing for earlier weight bearing to accelerate fracture healing with low risk of loss of fracture alignment.
LEVEL OF EVIDENCE
Level III Prognostic.