The effect of butterfly fragment characteristics on recovery in conservatively treated robinson TYPE 2B1 clavicle fractures

The aim of this study was to reveal the effects of fracture fragments and butterfly fragment features on the union level in displaced clavicle shaft fractures with butterfly fragments (Type 2B1 with butterfly fragments according to Robinson classification and 15.2B according to AO/OTA classification) and to create an algorithm that will facilitate the prediction of the physician in terms of the risk of delayed union or nonunion at the beginning of the treatment. In our study, we evaluated the radiographic results of 31 patients with butterfly fragment Robinson type 2B1 clavicle fracture, who were treated conservatively between 2015 and 2019, during their 24-week follow-up. 29 were male and 2 were female of the 31 patients included in the study and their mean age was 43.58 (21-75 years). The fracture site was right in 11 patients and left in 20 patients. 70% of the fractures were due to traffic accidents, 30% were due to simple or falling from a height. Radiologic fracture parameters were measured and recorded in the anteroposterior (AP) radiographs of the patients taken after injury. These parameters were vertical translation amount, shortening amount, clavicle angle, butterfly fragment length, butterfly fragment angle, butterfly fragment position and butterfly fragment overlap amount. The averages of the first 5 parameters, respectively; 125% recorded as 18.37mm, 11.27°, 21.72mm, 50.18°. 19 of the patients were treated with a figure 8 bandage and the remaining 12 patients were treated with a simple arm sling. Union levels were calculated with the M-RUSC Score (It was created by modifying the M-RUST score used in long bone union physicians.) on the control radiographs of the patients at the fourth, eighth, twelfth, and twenty-fourth weeks to evaluate the process of union. The demographic and radiological parameter differences between the groups were evaluated by dividing the patients into groups according to their union level in the relevant week. In all weeks of evaluation, it was determined that the amount of vertical translation affected the union level more than the butterfly fragment length (p<0.05). It was determined that the amount of shortening and the age of the patient affected the level of union only in the fourth week (p<0.05). In the radiological evaluation of the patients who were followed up conservatively at 24 weeks, 8 patients had no union and 10 patients had delayed union. The average of the vertical translation amount; It was determined that it was 153.5% in fractures with nonunion, 129.2% in fractures with delayed union, and 105.3% in healed fractures. It was determined that the only factor that greatly increased the risk of delayed union or nonunion, independent of other factors, was the amount of vertical translation (p<0.001). It was determined that vertical translation of more than 125% of the clavicle thickness after injury significantly increased the recovery time, and vertical translation of more than 142.5% of the clavicle would most likely cause nonunion (p<0.05). No factors were found within the butterfly fragment charasteristics to increase the risk of nonunion or delayed fusion. The fact that the rate of nonunion and delayed union observed in our study was higher than the literature may be due to the radiological evaluation of nonunion in our study. In order to avoid delayed union or nonunion pathology in acute Robinson type 2B1 clavicle shaft fracture with butterfly fragment, one of the primary criteria to be evaluated while determining the treatment strategy to be selected should be the amount of vertical translation. Fracture healing time will be prolonged if there is a vertical translation of more than 125% of the clavicle thickness between the main parts of the clavicle. Since this situation will cause labor and economic loss, it would be more appropriate to prioritize surgical treatment, especially in this type of fractures of young and active patients. Fractures of the clavicle shaft with a vertical displacement of more than 142.5% of the clavicle thickness between the main parts of the clavicle will most likely have nonunion. Therefore; In patients with this type of fracture, surgical treatment should be the primary option if there are no contraindications. In Robinson type 2B1 fractures with butterfly fragment, butterfly fragment characteristic are not important for the risk of nonunion or delayed union alone. Keywords: Clavicle, Clavicle Shaft Fractures, Butterfly Fragment