[Preparation and biomechanics study of biological artificial knee joint prosthesis with stereo mesh surface in rabbit]

Abstract

Objective: To develop a kind of biological artificial knee joint prosthesis with stereo mesh surface for rabbit, to observe its function after being implanted into rabbit knee joint and to evaluate its biomechanical property.

Methods: Thirty adult New Zealand rabbits were randomized into experimental and control groups (n=15), total left knee arthroplasty was performed in both groups, no patella replacement was performed. Biological artificial knee joint prosthesis with stereo mesh surface was self-designed. The adjacent 4/5 surface of femur and tibia stem of the prosthesis was covered by stainless steel stereo mesh, the inner surface of femur condyles and tibia plateau was welded with two layers of stainless steel stereo mesh, then the prosthesis underwent biological fixation in the experimental group. Meanwhile, prosthesis having smooth marrow internal stem, femoral condyle and tibial plateau internal surface and sharing the same shape and size with the experimental group were prepared and fixed with bone cement in the control group. The postoperative general condition of animal was observed. At 1, 3 and 6 months after operation, the rabbits were killed for gross observation, X-ray examination was conducted to observe the fixation condition of prosthesis and healing condition, the range of motion (ROM) of knee joints was tested, biomechanics test was carried out and the maximum shear strength of prosthesis bone interface was calculated.

Results: In each group, there was 1 rabbit died and new one was added during the second experiment. The others survived till the end of the experiment and crawled normally 7 days after operation. For the excellent and good rate concerning the recovery of ROM of the knee joint at 1, 3 and 6 months after operation, the experimental group was 60%, 80% and 80%, respectively, and the control group was 60%, 80% and 60%, respectively, indicating there were no significant differences between two groups (P > 0.05). For the experimental group, the gross observation showed large quantities of bone reconstruction, X-ray films indicated the prosthesis fitted well, with solid fixation and without dislocation and loosening; while for the control group, the gross observation showed no bone reconstruction, X-ray films displayed the location of prosthesis was good, with solid fixation and without dislocation and loosening. Radiolucent zone around the femur prosthesis and stress shielding occurred 6 months after operation. For the maximum shear strength, the experimental group was less than the control group at 1 month after operation; and it was higher than the control group at 3 and 6 months after operation, indicating there were significant differences between two groups (P < 0.01).

Conclusion: The fixation strength of the biological artificial knee joint prosthesis with stereo mesh surface is better than that of the bone cement prosthesis in rabbits at 3 and 6 months after operation.