Considering the Normal Tibial Values of Axial Rotation in Adults for Deformity Correction Osteotomies and Post-Operative Evaluation of Complex Tibial Fractures

Abstract

Category:Trauma; OtherIntroduction/Purpose:Tibial torsion has been mainly analyzed in pediatric deformities of lower limbs. Nevertheless this parameter has acquired relevancy in treatment of rotational deformities in adult population, that require axial correction. There are few articles that report normal values of tibial torsion, mostly in children, parameter that must be corrected in deformities to improve long term outcomes. Normal values in our population need to be established for preoperative planning and corrections. Our objective is to establish a normality parameter of tibial torsion in adults, that helps us in surgical planning of tibial rotational mal alignment and evaluation of the postoperative axial axis in complex tibial fractures.Methods:Descriptive study. We analyzed 18 computed tomography of 18 patients (35 tibias), through the Horos v.3.3.5 program, specifically in the 3D curved-MPR. Inclusion criteria: adult patients, without prior knee, leg or ankle deformities, without post-traumatic sequelae of the limb. Exclusion criteria: severe osteoarthritis of the knee or ankle, presence of osteosynthesis material in the limb, presence of previous osteotomies. Measurements were performed in standardized form previously defined by two foot and ankle orthopedic surgeons. We establish the comparison between both legs of each patient to determine posible variability and measurement interobserver correlations through kappa values.Results:All continuous variables are reported as means +- standard deviations. Student t-test was performed for continuous variables depending on the normality of the data distribution. We also performed de paired t-test to identify any significant differences in left and right tibial measurements. Statistical analyses were carried out by an independent statistician using Stata 16 statistical software. Measurements were performed establishing parameters in axial cuts of the tibia and overlapping two images previously determined. 18 patients (35 tibias) were measured, one limb was deleted for severe compromise the tibial plafond by osteoarthritis. 15 male and 3 female patients with an average of 65 years old (62-76 years). Mean external rotation of the distal tibial was 33° (16.1°-49.8°), difference between left and right tibias was in mean values of 1.95°, not being considered statistically significant. Interobserver correlation was reported at 97% in left tibia and 98% in the right, by intraclass correlation.Conclusion:Tibial torsion is an important component when correcting tibial axial deformities in adults. Our study shows higher normal values than the ones reported in current literature, but it is important to mention that the best parameter of evaluation is the comparison with the contralateral extremity of each patient.