Experimental study on mechanical and biomechanical reconstruction of bone defect of long bone near joint

Chunming HU; Wei ZHANG; Yun SU; Chengxue WANG; Xinxiang XU; Baoshun LU

ABSTRACT

BACKGROUND:

The repairing of bone defect near joint in long bone resulting from complicated comminuted fracture or excision of bone tumor is very difficult. It is a much studied issue to find a feasible solution to this problem.

OBJECTIVE:

To explore a feasible treatment to bone defect near joint in long bone through comparative observation of 3 reconstruction methods.

DESIGN:

A completely randomized experiment with self-control and mutual control.

SETTING:

Laboratory for Experimental Animals, First Hospital of Jilin University.MATERIALS Twelve healthy adult hybrid dogs, 5 males and 7 females weighing 12 to 18 kg, were recruited.

METHODS:

The bone defects near joints were established in upper femoral condyle in the 12 dogs, which were reconstructed by 3 operation styles only filling with bone cement, filling with bone cement + autogenous ilium bone graft, and filling with bone cement + autogenous ilium bone graft + fixation with L-trapezoid compression plate. There was one dog in each method. The specimens were harvested at the end of weeks 3, 6, 12and 24, respectively, after operation. One week before specimens were harvested the fluorescent labeling was prepared; we conducted vascular perfusion of disulphine blue before the animals were executed.MAIN OUTCOME

MEASURES:

A series of examinations were carried out, including X-ray film, biomechanical test, intravascular perfusion and tetracycline fluorescent labeling. The bone healing, blood supply recovery and biomechanics were observed in the three groups.

RESULTS:

The 12 dogs all entered the result analysis. ① Results of Xray examination Two cases of fracture occurred in experimental side at 6and 12 weeks in group Ⅰ; one case of fracture occurred in experimental side at 6 weeks in group Ⅱ. No fracture happened in group Ⅲ. ② Bone stiffness assayed with biomechanics It decreased in experimental side as compared to control side by 67% and 70% in group Ⅰ; 66%, 76% and 46% in group Ⅱ; and 8% in group Ⅲ. ③ Specimen observation after operation Bone formation, callus, and blood supply recovery were significantly better in group Ⅲ than in groups Ⅰ and Ⅱ at all stages.

CONCLUSION:

The third operation, filling with bone cement + autogenous ilium bone graft + fixation with L-trapezoid compression plate, is an ideal method of bone reconstruction. It can recover bone function, and prevent complications such as refracture and bone nonunion.