Universal reposition and fixation ring for surgical treatment of acetabulum fractures: preliminary results of laboratory static tests

BACKGROUND: Several structures are widely used in the surgical treatment of long-standing fractures of the BB, such as support rings of M. Muller, BurchSchneider, rings of PROTEK (Switzerland) implanted in the BB. In traumatology practice, rings are used to strengthen fractured walls. However, these rings are not functionally designed for open reposition and fixation of columns and fractures, followed by TBS endoprosthetics with cement fixation of the components of the endoprosthesis. Recently, primary endoprosthetics of EP TBS became the trend for displaced fractures of the BB, which is considered the best option for surgical treatment of BB fractures. In the literature, no analogs of our ring were available, which provides CHP in the treatment of BB fractures. 
AIM: To study the deformation properties of a repositional fixation ring with an outer diameter of 52 mm with a stiffening rib. 
MATERIALS AND METHODS: A ring has been developed for the surgical treatment of acetabulum fractures (Patent for Invention No. 2692526 dated 26.06.2019 under Application No. 2018133671 dated 25.09.2018.; Bul. No. 18 dated 26.06.2019). For mechanical testing, a ring with an outer diameter of 52 mm with a stiffening rib was manufactured by sequential sintering using additive technologies by Konmet LLC (Moscow). Laboratory mechanical tests were conducted by the Testing Laboratory of Medical Devices and Materials of the FSBI NMIC TO named after N.N. Priorov (Moscow). 
RESULTS: A static testing of a ring with a stiffener for compression, stretching, torsion, joint stretching, and twisting of the edges of the ring connector was performed, and its deformation properties and reaction to external loads during static tests were examined. The load corresponded to the deformation of 2 mm, kN; compression, 0.209; tension, 0.082; torsion (angle of rotation of 5 degrees, Nm), 9.422; and joint stretching with twisting of the edges of the ring connector (load corresponding to the deformation of 10 mm, kN), 0.060. 
CONCLUSION: The results of the initial study of the deformation behaviors of the new ring design clearly show the elastic nature and deformation properties of the ring, which were attributed to the stiffening rib. The positive primary results of studying the deformation behaviors of the ring reinforced with a stiffening rib indicate the possibility for clinical trials and the direction of further refinement of the design..