Early versus delayed weight bearing after intramedullary nailing for tibial shaft fracture: A multicenter, propensity score-matched study, the TRON study.

Objectives: The purpose of this multicenter study was to assess the differences in the rates of implant failure and bone union by X-ray examination, and walking ability between an early weight-bearing group (EWB) and a non-weight-bearing group (NWB) following treatment with intramedullary nailing (IMN) for tibial shaft fractures with a propensity score-matching method.

Material And Methods: We collected data from 336 patients with tibia fractures that were treated surgically. We excluded patients lost to follow-up and polytrauma patients. Finally, 263 patients were included who were divided into two groups, the early weight-bearing (EWB) group, in which partial weight-bearing walking within four weeks was encouraged, and a non-weight-bearing (NWB) group, in which no weight bearing was allowed for more than four weeks. To adjust for baseline differences between groups, a propensity score algorithm was used to match the EWB group with the NWB group in a 1:1 ratio of 75 cases each. After matching, we compared the rate of implant failure, the rate of bone union at six months and one year after surgery, and walking ability at the last follow-up between the two groups.

Result: Implant failure occurred in 0 of 75 patients in the EWB group vs. 1 of 75 in the NWB group (P = 1.0). Delayed bone union at six months occurred in 20 of 75 (26%) vs. 13 of 75 (17%) patients, and that at one year occurred in 5 of 75 (6.7%) vs. 3 of 75 (4%) patients. The median New Mobility Score was 9 (4-9) vs. 9 (0-9) points.

Conclusions: There were no statistically significant differences in the rate of implant failure, the rates of the bone union at six months and one year after surgery, and walking ability between the EWB group and NWB group. We suggest that instruction in early weight-bearing after IMN nailing for tibial shaft fracture may not be harmful.