To investigate the effects of biodegradable Mg-Zn alloy rib contractor in rib internal fixation and its degradation process, in order to provide experimental evidence for clinical study.

The novel biodegradable Mg-Zn alloy rib contractor was prepared. Fifteen Beagle dogs were used to establish the model of animal multiple ribs fracture, and were divided into Mg-Zn alloy group (experiment group, n=10) and steel panel group (control group, n=5). Rib internal fixation was performed in each dog. The incision reaction, body weight and incidences of postoperative complications were compared between two groups. Chest CT examinations were performed 2, 4, 8 and 12 weeks after operation, and CT three dimensional reconstruction of thoracic cage was done. The dogs were sacrificed 4, 8 and 12 weeks after operation, the degradation of Mg-Zn alloy rib contractor was observed, and the histopathological features of callus were examined in experiment group.

There was no perioperative death in two groups, and there was no significant difference in body weight and incidences of postoperative complications between two groups. Incision infection occurred in one dog in experiment group, which was healed after proper management. Twelve weeks after operation, HE staining demonstrated that the rib fracture was healed, with unclear borderline and no inflammatory cell infiltration. Chest CT examination and three-dimensional reconstruction indicated that the rib fracture was healed and Mg-Zn alloy was completely degraded.

Biodegradable Mg-Zn alloy is feasible for rib internal fixation, with no unfavorable effect on the surrounding tissues, which may have a good clinical prospect.