| Objective 1,To evaluate the intensity of the long bone comminuted fracture whileusing a ptate fixation, which own a bony defect on side of plate, To provide some basicscientifically evidence for long bone comminuted fracture with cortical fragment for futureclinical practice.Methods 1,biomechanical testing: Twenty-four femurs of fresh corpse were taken andmade cortical wedged-defect in middle-part of the medial femur. And it was divided into fourgroups at randomly (n=6), The vertical compression,bending and torsion intensity in withoutand with reduction of cortical fragment of plate fixated contra side (team A and team C),without and with reduction of cortical fragment of plate fixated side (team B and teamD)weremeasured. All results were analyzed with statistic method. 2,animal experiment: The 12adult goats were divided into two group at randomly, wedged cortical defect with 1 cm oflong and conjugate diameter was created in the middle-part of the medial femur and plate wasfixed in the defect side and as the experimental side, the other side was control.after operation4,8,12 weeks,investigation of the fracture healing by means of gross observation, X-rayexamination and histology in both sides. Grading the score of X-ray and histologyobservations according to Lane imaginological and histological standard.Results 1,biomechanical testing:In team A the means stiffness of verticalcompression, bending and rotation, were 986.85N/mm,481.91N/mm and 2.83N/Degree(team B:1422.27 Degree N/mm,852.17N/mm and 3.62N/Degree;team C: 1166.88N/mm,739.92N/mm and 3.21N/Degree;team D1831.74N/mm,893.84N/mm and 5.73N/Degree)respectively.The results showed an statistical difference between the team B and team D inthe bending(p＜0.05).the others were obvious statistical difference in the verticalcompression, bending and torsion angle.(p＜0.001), it was worst to use the team A ,team Bwas better , and team D was best. 2,imaginology: after operation, 7 implants failure was observed at the control side,however all implants were natural at the experimental side. after 4,8 weeks, the rate andqulity of the new bone formation was statistical different between the experiment and thecontrol sides from X-ray examination according to Lane imaginological standard(p＜0.05)(3.50±0.58VS1.50±0.58, 4.50±0.58VS3.00±0.82). yet, at 12weeks after operation,there is obviously statistical different between the two sides(p＜0.01)(10.00±1.83VS3.50±1.00).3,histopathology:after 4 weeks, Histopathological examination showed that there weremuch chondral callus in bone defects site in experimental side, while in control side there aremore fibrous callus; after 8 weeks, much osteal callus and some chondral callus wereobserved in bone defects in experimental side, while observed much fibrous callus,somechondral callus and fewer osteal callus in the other side; after 12 weeks, much chondralcallus,some osteal callus and fewer fibrous callus were observed in control side, fractures ofexperimental femur were healed with a lot of osteal callus.at 4,8,12 weeks, there wasobvious different between the two sides according to Lane histological standard (3:75±1.256VS 2.50±1.29,7.50±1.26VS3.75±0.50, 10.75±1.26VS5.00±0.81) respectively.Condusions To reconstruct the supporting intensity in mechanics,increase stability afterfracture interfixtion,promote bone healing,short the time of bone healing and prevent thefailure of fixation, the method of plate fixed in the defect side is worth applying in theclinical.
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