Early Experimental Study On Carpal Scaphoid Replaced By The Composite Materials Of Nano-hydroxyapatite / Polyamide 66 Wrapped By Autologous Periosteum, Tendon

Objective: To investigate whether the composite materials of dense nano- hydroxyapatite / polyamide 66 (nHA/PA66) wrapped by autologous periosteum and tendon can reconstructe carpal scaphoid.Methods: 36 New Zealand white rabbits were randomly divided into three groups, A, B and C, 12 rabbits per group. Group A: composite material of dense nHA/PA66 wrapped by autologous periosteum and tendon; Group B: composite material of dense nHA/PA66 wrapped by autologous tendon; Group C: autologous tendon ball alone. After bilateral carpal bones were completely removed, the above three materials were respectively implanted to replace radial carpal bone. 3,6,12 weeks after surgery, the whole wrist was collected for gross observation, radiological and histological examination,and carpometacarpal index whose data were statistically analyzed .Results: In Group A, 3 and 6 weeks after surgery, a small amount of chondroblasts were found on the surface of the composite material of nHA/PA66; 12 weeks after surgery, chondroblasts increased and transparent cartilage formed around the material. The composite materials of nHA/PA66 were combined more closely with soft tissue around by the firbers in the twelfth week than that in the third or the sixth week. During different time periods, no composite materials of nHA/PA66 were fragmentated, absorbed or degraded. In Group B and C, no transparent cartilage was found around the implants during different periods, but the gross observation and radiological examination showed that the cartilage in wrists lost obviously and the wrists collapsed significantly in Group C more that those in Group A and B.The statistical analysis of sample with carpometacarpal index,A,B group had no significantly lower(P>0.05), C group had significantly lower(P<0.01).Conclusion: That autologous periosteum and tendon wrapping dense nHA/PA66 cound form composite materials in the wrist joint cavity; hyaline-like cartilage could form on their surface, and the materials were so strong that they could be used to replace scaphoid bones .