THE BIOMECHANICAL ANALYSIS OF PELVIC OSTEOTOMIES APPLIED FOR DDH TREATMENT IN PEDIATRIC PATIENTS

The aim: This article aimed to evaluate biomechanical changes during the most commonly used pelvic osteotomies (Salter, Dega, Pemberton) for DDH treatment in pediatric patients.Materials and methods: Virtual pelvic models of 2- and 6-years old patients were created, material properties were assigned, pelvic osteotomies were simulated and biomechanical changes were evaluated using finite element analysis (FEA).Results: It was revealed that the patient's age impacts pelvic bones and cartilage density (in younger patients the pelvic elements are more pliable - p<0.05). Stress distribution after each of the abovementioned pelvic osteotomy was assessed in 2- and 6-year-old patients' pelvic models. The new term "restriction point" was introduced, which means a place where restriction of acetabular deformity correction occurs.Conclusions: It was found that there are no purely reshaping and reorientation pelvic osteotomies as previously believed; the pelvic ring acts as a unit in carrying out the applied load. Biomechanical overload of triradiate cartilage during Salter osteotomy in 2-year-old patients and in 2- and 6-year-old patients during Pemberton osteotomy was revealed; overload of the posterior cortical layer in the greater sciatic notch in 2-years old patient during Dega osteotomy was revealed.