Articular cartilage changes.

The morphologic changes of articular cartilage with bone grafting to fill subchondral bone defects were studied in 23-month-old New Zealand rabbits with bilateral tibial subchondral bone defects. The defects were made approximately 5 mm below the articular surface and were covered with surrounding tissues. The right side was filled with calcium sulfate bone graft, and the left side was filled with acrylic cement as control. The articular cartilage above the fillers was harvested 12 weeks postoperatively. Gross observation, histological examination, and transmission electron microscope observation were undertaken. The results showed that cartilage above the calcium sulfate had a normal hyaline articular cartilage appearance. In contrast, cartilage above the acrylic cement showed degenerative changes in both histological and electron microscope observation. These results suggest that using calcium sulfate bone graft to fill subchondral metaphyseal bone defects has no harmful effect to overlying articular cartilage. This substitute can reduce the possibility of osteoarthritis compared to acrylic cement.

Total hip arthroplasty for acetabular protrusion / 中国矫形外科杂志

[Objective]To discuss the outcome of acetabular protrusion after total hip arthroplasty. [Method]Fifteen patients(M=7,F=9) having painful acetabular protrusion received total hip arthroplasty with reinforcement of the acetabulum with bone grafts(autogenous or allogeneous bone).The results were reported at 1~4 years(mean,3 years) of follow-up.Of the 15 cases,5 were mild protrusion and 10 were moderate protrusion.The Harris hip-rating and radiographs were taken pre-and postoperatively. [Result]The average Harris hip-rating was improved from 45 points(range,39~60 points) preoperatively to 85 points(range,70~100 points) postoperatively.The average preoperative protrusion of the femoral head medial to the Kohler line was 8.8 mm(6~18 mm).The average postoperative placement of the prosthetic femoral head was 10 mm(6~13 mm) lateral to the Kohler line.None acetabulum prothesis failure or bone grafts absorption was seen.The grafts were well incorporated on radiograms in all patients one year after operation by radiographs. [Conclusion]Good results can be obtained in hips with acetabular protrusion after reconstructed with autogeneous or allogeneous bone grafting and total hip arthroplasty.