[Objective]To investigate the pathological change of articular cartilage after impacting injury.[Method]Fifty-six New Zealand adult rabbits were divided randomly into low-energy and high-energy groups,with 28 rabbits in each group.One side of hind limb was designed as experimental side and the opposite one as control side.Four rabbits were killed at 4 days,1,2,4,8,16 weeks after impacting injury.Histological sections of the specimens were observed and stained by HE and Safranin O.the values of gray scale were obtained by imaging analysis.[Result]In low-energy group,the Mankin's score and the value of gray scale of Safranin O in experiment side was not significantly different from the control side.In high-energy group,the Mankin's score and the value of gray scale of Safranin O in experiment side increased gradually,and was significantly different from the control side.[Conclusion]In the low-energy group,the cartilage returned to the normal level at 4 weeks.In the high-energy group,the cartilage failed to be restored.The degeneration of articular cartilage was very obvious after 4 weeks.

[Objective]To observate the successive status of chondrocyte apoptosis after impacting injury of articular cartilage by TUNEL marking method and transmission electron microscope(TEM).[Method]Fifty-six New Zealand adult rabbits were divided randomly into low-energy and high-energy two groups,each group was 28.Femoral medial condylar cartilage of one side was injuked by impacting in experimental group,the opposite side as control group.Four rabbits were killed and their medial femoral condylar cartilages were taken at each of the following intervals:4 days,1,2,4,8,16,32 weeks after impacting injury.The specimens were observed as pathology histological sections and strained by TUNEL to measured the rate of chondrocyte apoptosis.[Result]In early stage of post-injury,the rate of chondrocyte apoptosis in and high-energy is significantly higher than that of control group.After 4 weeks,the rate of chondrocyte apoptosis decreases to the level of that of control group in low-energy.In high-energy group,the rate of chondrocyte apoptosis is constantly upgraded-phase,higer significantly than the level of that of control group.[Conclusion]In early stage of post-injury,the rate of chondrocyte apoptosis in low and high-energy was significantly higher than that of control group.After 4 weeks,the rate of chondrocyte apoptosis decreased to the level of control group in low-energy.In high-energy group,the rate of chondrocyte apoptosis is constantly upgraded-phase,higer significantly than the level of control group.

BACKGROUND:Femoral head avascular necrosis is common in children and elderly. Though, there are many methods can be used for the treatment, it has been inconclusive in the treatment according to the age and stage of the patients. OBJECTIVE:To treat the femoral head avascular necrosis with different methods according to the age and stage, and to retrospectively analyze the fol ow-up results. METHODS:Total y 202 patients (242 hips) with femoral head avascular necrosis were included from October 1998 to October 2008. The patients were divided into groups according to age, included child group (4-14 years old, n=45, 47 hips);youth group (15-45 years old, n=100, 125 hips);and elderly group (46-81 years old, n=57, 70 hips). The patients in the child group were treated with vascularized greater trochanter or iliac periosteal flap displacement, the patients in the youth group were treated with vascularized greater trochanter or iliac periosteal flap displacement, and the patients in the elderly group were treated with hybrid or cementless total hip arthroplasty. RESULTS AND CONCLUSION:Al the 202 patients were fol owed-up for 6 months to 10 years, average 6.3 years. The excellent and good rate of the child group, youth group and elderly group were 87%, 89%and 86%respectively, and al the patients obtained the satisfactory clinical effect;the Harris score of the youth group was increased to (88.1±0.9) points, and the visual analog scale score was decreased to (0.9±0.4) points;the Harris score of the elderly group was increased to (91.5±1.0) points, and the visual analog scale score was decreased to (0.60±0.07) points. The results indicate that vascularized greater trochanter or iliac periosteal flap displacement is suitable for the children and the youths with femoral head avascular necrosis, especial y the patients with the age of 15-45 years in Ficat Ⅱ and Ⅲstage;hybrid or cementless total hip arthroplasty is suitable for the elder patients with femoral head avascular necrosis, as wel as the patients with failure femoral head retention treatment.