Retrospective evaluation of factors on fracture healing after intramedullary nailing in tibia shaft fractures

Intramedullary nailing after tibial shaft fractures provides a suitable biologically and mechanically advantageous environment for fracture healing. It is extremely important to ensure optimum compatibility between the patient's bone anatomy and the implant in order to stabilize the fracture by providing an uninterrupted internal connection between the proximal and distal fracture line as well as allowing micro-movement at the fracture line. In this retrospective and monocenter study, it was aimed to evaluate the factors affecting fracture healing after intramedullary nailing in tibial shaft fractures. The primary outcome variable of the study is the determination of an optimal size relationship between the diameter of the tibia isthmus and the size of the intramedullary nail that will positively affect the union. For this purpose, 323 patients with tibial fractures who were treated in Akdeniz University Orthopedics and Traumatology Clinic between January 2014 and January 2019 were identified. It was determined that osteosynthesis was performed with intramedullary nailing for 156 patients with tibial shaft fractures. 21 patients were excluded because they did not meet the study criteria, and 32 of the remaining 138 patients with tibial shaft fractures were excluded due to irregular follow-up. Finally, a study group was formed with 103 patients with 106 tibial shaft fractures. Nail diameter/isthmus ratio was determined for all cases. Two-way radiographs of the patients at 3-6-9-12 months were evaluated separately by 2 different observers, the mean score was obtained by RUST scoring, and fracture union was evaluated. Monthly bilateral radiographs were evaluated separately, mean score was obtained by RUST scoring, and fracture union was evaluated. Univariate and multivariate statistical analyzes were performed to determine other factors (patient demographic, clinical, postoperative radiological measurements) that may have an effect on union. In order to investigate the effect of nail diameter/isthmus ratio on union, the cut-off point of the measurements was 0.85 at the limit level, at the consistency level of 69%, the sensitivity level of 98%, the specificity level of 79%, and the statistical significance on union was determined as a result of ROC analysis. It was found that it was not significant on union in the first 6 months, but when the patients who were found to have union at the 9th and 12th months after the 6th month were evaluated, the nail/isthmus diameter ratio was above 0.85 and had a significant effect on the union. A ratio relationship was determined between the diameter of the tibia isthmus and the diameter of the intramedullary nail, which will positively affect the union, and the fact that the ratio of intramedullary nail/canal diameter is close to or above this level in order to optimize the healing of tibial shaft fractures shows that it will have a significant effect on union in the future. When other parameters that may be effective on union are examined; union rates of proximal diaphyseal fractures were lower. Compared to closed tibial shaft fractures treated with an intramedullary nail, open fractures showed radiological union in a longer period. It has been observed that smoking and/or alcohol use have negative effects on early and late recovery. It has been shown that the presence of diabetes, high ASA score and high BMI in the patient may have a negative effect on late recovery. It has been shown that postoperative union rates are lower in patients who were applied external fixation as the primary treatment option and then electively preferred fixation with IM nails. It was observed that the rate of union was lower at the postoperative 6th month in the patient group in which the primary treatment external fixator was applied and the fixation with IM nail was applied electively. The similar situation is still valid in the 9th month; union rates were found to be lower. It was determined that the lower the postoperative diastase level, the better the union rate.