Effect of the locking compression plate by internal fixation on fracture healing of dog bilateral middle tibia

Lijun XIAO

ABSTRACT

BACKGROUND:

BO theory is introduced based on AO theory with the more attention to biological performance of fracture healing, which seriously promote the rapid development of bone plate.

OBJECTIVE:

To study the effect of the locking compression plate (LCP) by internal fixation on fracture healing of dog bilateral middle tibia. DESIGN, TIME AND

SETTING:

A contrast study was performed at the Traumatic Orthopaedics Tissue Engineering Laboratory of Southern Medical University from June 2006 to October 2007. MATERIALS A total of 24 healthy adult dogs weighing 14.5-21.2 kg and of either gender were used to prepare bilateral middle tibia fracture models. LCP was made of 316L stainless steel and provided by Zhengtian Medical Apparatus Co., Ltd., Tianjin. Conventional AO stainless steel plate was provided by Mateshi (Shanghai) Medical Apparatus Trading Co., Ltd.

METHODS:

Right tibia was treated with internal fixation of LCP as the experimental group, and left tibia was treated with conventional AO plate as the control group. MAIN OUTCOME

MEASURES:

Samples were performed with X-ray examination, optic microscope, and microangiography, while microvessel image surface fraction was analyzed at 2, 4, and 6 weeks after operation.

RESULTS:

① X-ray examination The fractures healed well in both the experimental group and the control group, but a lot of bone calluses were found in the experimental group; while absorption and attenuation were found in bone cortex in the control group. ② Optic microscope Bone absorption cavity was found in the control group, and structure of osteocytes was destroyed mostly. Bone absorption cavity was not found in the experimental group, and structure of plentiful osteocytes was intact. ③ Microangiography A large area of ischemic region was found in bone cortex in the control group 2 weeks postoperatively and still observed 6 weeks postoperatively. A small area of ischemic region was found in the experimental group 2 weeks postoperatively; however, courser and distribution of microvessels were disorder. Six weeks later, the ischemic region disappeared generally, and courser of microvessels generally reached normal level. ④ Microvascular image surface fraction At 2, 4, and 6 weeks postoperatively, the surface fraction in the experimental group was 1.78, 2.26, and 2.69 times as control group, and there was significant difference between them (P