Influence of the fixation with auto-control micro-movement intramedullary interlocking nail mode on fracture healing in goats

AIM: To investigate the effect of auto-control micro-movement locking nail (AMLN) on experimental fracture healing. METHODS: 32 goats with a transverse osteotomy of the femoral shafts (16 matched pairs) were fixed intramedullary with AMLN and Gross-Kempf (GK), respectively. The follow-up time was 7, 14, 28 and 56 days, histological and biochemical analysis were done. RESULTS: (1) Histological observation and quantitative analysis of calluses revealed that AMLN promoted the growth of bridge calluses and periosteum calluses. In that way the facture healing and remodeling process came along ahead of time that was much better than traditional GK nail fixation. The significant difference between them was observed (P<0.05). (2) The content of the total collagen, insoluble collagen, calcium and phosphate in the AMLN fixed group were higher than those in the GK nail fixed group (P<0.05). CONCLUSIONS: The design of AMLN accords well with the plastic fixation theory. The generation and conduct of the intermittent physical stress between the fractural parts could resolve the balance problem between stress conduct and stress protection. The fracture end could heal and remodeling at the same time which speed up the fractural healing process.