[Experimental study on promoting bone consolidation by using platelet-rich plasma and decalcified bone matrix during distraction osteogenesis].

OBJECTIVE: To investigate whether combining use of platelet-rich plasma (PRP) and decalcified bone matrix (DBM) has synergistic action on promoting bone consolidation and healing.

METHODS: Forty male New Zealand rabbits (weighing 2.2-2.8 kg) were randomly divided into 4 groups (n = 10). The whole blood was extracted from the central aural artery and PRP was prepared with the Landesberg's method. An 1 cm-defect was made below the tibiofibular joint of the left tibia through osteotomy. In group A, defect was repaired by distraction osteogenesis (1 cm); in group B, defect was repaired with 0.5 cm DBM and then by distraction osteogenesis (0.5 cm); in group C, defect was repaired by distraction osteogenesis (1 cm) and local injection of 1 mL PRP; in group D, defect was repaired by 0.5 cm DBM combined with 1 mL PRP and then by distraction osteogenesis (0.5 cm). Then lengthening started at 7 days after operation, at a rate of 1 mm/day and 0.5 mm every time for 10 days (groups A and C) or for 5 days (groups B and D). After the lengthening, the consolidation was performed. The X-ray films were taken at 0, 12, 17, 27, and 37 days after operation. At 37 days after operation, the tibial specimens were harvested for Micro-CT scanning, three-dimensional reconstruction and biomechanical test.

RESULTS: The X-ray films showed that new bone formation in groups B and C was obviously better than that in groups A and D at 37 days. The bone mineral density (BMD), bone mineral content (BMC), and bone volume fraction (BVF) of groups B and C were significantly higher than those of groups A and D (P < 0.05); the BMD and BMC of group C were significantly higher than those of group B (P < 0.05); the BVF had no significant difference between groups B and C (P > 0.05). There was no significant difference in BMD, BMC, and BVF between groups A and D (P > 0.05). The trabecula number (Tb.N) of group C was significantly more than that of other groups (P < 0.05), and the trabecula spacing (Tb.Sp) of group C was significantly smaller than that of other groups (P < 0.05), but no significant difference was found among other groups (P > 0.05). There was no significant difference in the trabecula thickness among 4 groups (P > 0.05). The ultimate angular displacement had no significant difference among 4 groups (P > 0.05). The maximum torque of groups B and C was significantly higher than that of groups A and D (P < 0.05); the maximum torque of group C was significantly higher than that of group B (P < 0.05); no significant difference was found between groups A and D (P > 0.05).

CONCLUSION: In the rabbit bone defect/lengthening model, local injection of PRP can enhance bone consolidation effectively during consolidation phase. In normal distraction rate, DBM can promote bone consolidation during distraction osteogenesis. In the early stage of distraction osteogenesis, combining use of DBM and PRP can not further promote bone consolidation and healing.