BACKGROUND:Correlation between subchondral bone and articular cartilage in the process of osteoarthritis has not been fuly elucidated. Degeneration of cartilage is the focus of attention, and the subchondral bone also plays an important role in the process of osteoarthritis. OBJECTIVE: To observe the differences between experimental osteoarthritis models in rabbit knees established by two kinds of surgical methods and two kinds of proteases inducing methods, and to explore the correlation between subchondral bone mass and degeneration of cartilage. METHODS:Thirty-two New Zealand rabbits were randomly and averagely divided into four groups: Hulth group (group A), anterior cruciate ligament transaction group (group B), colagenase type II group (group C) and papain group (group D). The right knees of rabbits were established as osteoarthritis models, and the left knees served as controls. Bone mineral density of the knee joint was evaluated by dual-energy X-ray absorptiometry scanning at 0, 4 and 8 weeks after modeling. The rabbits were sacrificed at 8 weeks after MRI scanning, bilateral knee joints were harvested for general and histological observation. Quantitative analysis was done according to Mankin scores. RESULTS AND CONCLUSION: Bone mineral density of the right knees decreased at 0, 4 and 8 weeks after modeling, and the rank was as folows: group A > group B > group C > group D. MRI scanning showed that the articular cartilage thickness of the medial and lateral femoral condyle on the right knees became thinner compared with the left side, and the rank was as folows: group A < group B < group C < group D. Observation by specimens and pathological slices showed that the articular cartilage degeneration of the surgery groups worsened, group A was the most serious one, and group 1D was the lightest. Both surgery and proteases inducing methods can successfuly establish osteoarthritis models in rabbit knees. Surgery inducing models resemble the advanced or intermediate stage of osteoarthritis, while the proteases inducing models resemble the early stage of osteoarthritis. Degeneration of the articular cartilage and changes of subchondral bone are related in progressive development.

[Objective]To investigate the efficacy of total hip arthroplasty(THA)on the treatment of traumatic arthritis that caused by internal fixation failures of intertrochanteric fractures.[Methods]During January 2009 and March 2016,35 cases of trau?matic arthritis(male:18 cases;female17 cases;49 ~ 86 years old,with an average age of 68.5 years)caused by internal fixation failures or malunion of intertrochanteric fractures,were undergo THA. Among 35 cases,13 cases were performed with the proximal femoral fixation stems,10 cases were with distal fixation stems,and 12 cases were with extended stems.[Results]With 3~65 months follow-up,the hip joint HSS score was elevated from 44.1(31 ~ 65)preoperative to 82.5(58 ~ 94)postoperative without obvious loosening. No postoperative deep infectionwas found. The femoral stems in 2 cases were found to sink 5 mm and 10 mm,respectively. No obvious prosthesis loosening was found. Taken together ,the satisfaction rate of THA on the joint function of traumatic arthritis was 91.4%.[Conclusion]Total hip arthroplasty is recommended as an effective approach for treating traumatic arthritis caused by internal fixation failures of intertrochanteric fractures. Distal fixed prosthesis was recommended due to bone sclerosis or defects of proximal femur. Coupled with emphasis on reconstruction of the greater trochanter ,good therapeutic effects could be achieved.