Healing of physeal fracture after fixation with biodegradable self-reinforced polyglycolic acid pins. An experimental study on growing rabbits.

Physeal fractures occur at a frequency of 15% of all long bone fractures in children. Undisturbed continued bone growth is the main goal of the treatment of these fractures. After the operative reduction and fixation, whenever needed, a second operation for the removal of the pins is inevitable. The purpose of this study was to develop a biodegradable fixation device for transphyseal fracture fixation, abolishing the need of removal operation. Epiphyseal separation of the distal femoral physis was made on the right side in 18 five-week-old rabbits. The fixation of the physeal fracture was made with two self-reinforced polyglycolic acid (SR-PGA) pins 1mm in nominal diameter and 25mm in length. The follow-up times were 3, 6, 12, 24, and 28 weeks. The distal femoral growth-plate of both femurs was analyzed by radiographic, microradiographic, oxytetracycline-fluorescence, histological and histomorphometric studies. Histomorphometric studies showed normal features of growth. Two growth-plate-penetrating transcondylar SR-PGA implants, of 1mm in diameter, provided sufficient stability for the fixation of a distal femoral physeal fracture in a growing rabbit, and did not cause any growth disturbance.