Application of Wall Thickness Analysis in Estimating the Degree of Tibial Fracture Bone Healing / 医用生物力学

ABSTRACT

Objective To quantitatively judge the degree of tibial bone healing using the finite element wall thickness analysis method, so as to provide an intuitive diagnostic basis for clinical judgment of tibial union and delayed bone healing. Methods After three-dimensional (3D) modeling for the affected and healthy limb side of 48 patients, the maximum wall thickness (MWT) was calculated, and the ratio (B value) was used as a quantitative index of bone healing. When both BMWT2 and BMWT1 were greater than 0.9, bone healing could be judged. When BMWT2 was between 0.9 and 0.7, bone union was judged to be poor, and there was no significant increase in this value after regular reexamination. When BMWT3 was above 0.9 while both BMWT1 and BMWT2 were smaller than 0.7, it could be judged as internal fixation failure, which should be replaced during the second operation. The clinical diagnosis was revised twice, and the final clinical healing results were observed. Results Clinical diagnosis analysis and finite element wall thickness analysis were carried out in 48 patients during each review period, and 21 cases of delayed bone healing and 27 cases of bone nonunion were judged clinically. Among them, 2 cases were judged to be ineffective, and bone grafting intervention was adopted to replace the internal fixation, 12 cases were judged to be still effective, and all cases were finally healed by surgical intervention of bone grafting alone. By Bowker test, P=0.094 was obtained, indicating that the wall thickness analysis method was consistent with the clinical diagnosis. Conclusions The wall thickness analysis method can be used to quantitatively analyze the degree of bone healing at fracture end and realize the rapid calculation of bone healing degree. The case results in this study show that the finite element wall thickness analysis method is superior to the simple clinical diagnosis method, and has better differential diagnostic significance for early diagnosis of poor bone healing.