Objective To review the researches on the jointpreserving procedures for the treatment of the avascular necrosis (AVN) of the femoral head. Methods The latest original literatures about the joint-preserving procedures for the treatment of AVN of the femoral head were extensively reviewed. Results There were many surgical jointpreserving procedures to treat AVN of the femoral head, such as core decompression, bone grafting, and osteotomy. Most researchers achieved excellent clinical results by using the joint-preserving procedures to treat the early stages of AVN of the femoral head. Conclusion Treating AVN of the femoral head by the joint-preserving procedures, especially the free vascularized fibula grafting, can achieve an excellent longterm clinical outcome.
【Abstract】 Objective To measure the changes of bone mineral density and bone micro-architecture of thefemoral head that harvested from the three-foot bearing ethanol destroyed canine model for osteonecrosis of femoral head, and discuss the influences of local injection of ethanol and biomechanical loading to the structural properties of the femoral head. Methods Twenty-four Beagles were divided randomly into four-foot bearing canines and three-foot bearing canines. One fore-l imb was fixed randomly in three-foot bearing canines. Osteonecrosis was induced in all experimental animals by local injection of 5 mL pure ethanol into one side of the femoral head. The hind l imbs injected with NS were acted as control group, that of three-foot canines injected with ethanol were acted as three-foot canine group, and that of four-foot canines injected with ethanol were acted as four-foot canine group. The contralateral femoral head was injected into equal amount of NS. Animals were sacrificed at the time intervals of 1, 3, 6, and 12 weeks after the injection of ethanol. Quantitative microcomputedtomography was used to characterize changes in bone micro-architecture and bone mineral density of femoralhead. Results The clear three-dimensional model of trabecular bone of necrotic femoral head were obtained. There were no significant differences among 3 groups according to the time l ine by 1 week after ethanol injection(P gt; 0.05). At 3 weeks after injection of ethanol, in three-foot canine group and four-foot canine group, the volume of BMC, BMD, BVF, and BS/BV increased gradually as the distance to the drill ing canal increased. There were significant differences between 3 regions (P lt; 0.05). At 6 weeks, in three-foot canine group and four-foot canine group, the volume of BMC, BMD,BVF, and Tb.N of region I and II decreased significantly compared with region III (P lt; 0.05). At 12 weeks, there are no differences among 3 groups (P gt; 0.05). There were significant decreases in BMD values, BVF, BS/BV, Tb.N, Tb.Sp and Tb.Th after the injection of pure ethanol. And, the changes were more and more obvious by the time l ine. These changes were differentiable at 3 weeks after injection of ethanol, and became obvious at 6 weeks. These changes were more obvious at the part that near the injection canal. The changes in threefoot canine group were more obvious than that in four-foot canine group. Conclusion Resorption of necrotic compact bone trabecular may weaken the structural properties of the femoral head. Moreover, remodel ing and repairing process of necrotic bone trabecular may be hampered by constant biomechanical loading that presented in three-foot bearing canines, and thereby further weaken the structural properties of the femoral head. Biomechanical loading may be one of the critical reasons that lead to the collapse of femoral head.
【Abstract】 Objective To establ ish a three-foot weight-bearing canine model to imitate the biomechanical loading environment of the human’s hip joint. To observe and compare the kinetic changes of hind l imbs between normal and three-foot weight bearing canines. Methods Using 10 beagles, three-foot weight-bearing canine models were made by fixing unilateral wrist joints at 90º flexionally. The changes of ground reaction forces and the time of standing phases (Ts) of the hind l imbs were compared by 3-D gait analysis pre- and postoperatively. Results Canines could walk well with three l imbs after the fixation of one fore l imb. However, the gait pattern changed tremendously. The canine walked jumpily by raising its head and neck, and the bilateral hind l imbs kept contacting ground alternately. Ts of ipsilateral hind l imb was (0.48±0.04)s, and Ts of contralateral hind l imb was (0.46±0.06)s. Although, the time durations were increased a l ittle, but there were no significant differences when compared with that of normal canines (0.43±0.05)s (P gt; 0.05). The vertical ground reaction force (Fz) of ipsilateral hind l imbwas (4.63±0.85) body weight, and the Fz of contralateral hind l imb was (4.78±0.49) body weight. There were significant increases when compared with the Fz of normal canines (3.26±0.48) body weight (P lt; 0.05). The peak acceleration force of the ipsilateral hind l imb was (0.80±0.30) body weight. There was significant increase compared with that of normal canines (0.72±0.13) body weight (P lt; 0.05). The peak acceleration force of the contralateral hind l imbs was (0.68±0.22) body weight, there was no difference compared with that of normal canines (P gt; 0.05). The peak deceleration forces of the ipsilateral and contralateral hind l imbs were —(0.26±0.14) body weight and —(0.13±0.05) body weight separately. They decreased significantly when compared with that of normal canines —(0.43±0.13) body weight (P lt; 0.05). In normal canines, the upper l imbs were main load bearingl imbs, they could bear 62.8%±2.4% of body weight. However, the hind l imbs could bear only 37.2%±1.8% of body weight. On the contrary, in three-foot weight-bearing canines, the hind l imbs became the main load bearing l imbs, they could bear 59.1%±6.7% of body weight. Conclusion Three-foot weight-bearing canine model can be used as a candidate animal model to research the effects of biomechanical loading on the progression of hip joint diseases.