Protein-Degrading Enzymes in Osteoarthritis.

OBJECTIVE: TGFß1 plays an important role in the metabolism of articular cartilage and bone; however, the pathological mechanism and targets of TGFß1 in cartilage degradation and uncoupling of subchondral bone remodeling remain unclear. Therefore, in this study, we investigated the relationship between TGFß1 and major protein-degrading enzymes, and evaluated the role of high levels of active TGFß1 in the thickening of subchondral bone and calcification of articular cartilage. MATERIALS AND METHODS: The expression of TGFß1 and protein-degrading enzymes in clinical samples of articular cartilage and subchondral bone obtained from the knee joint of patients with osteoarthritis was detected by immunohistochemistry. The expression levels of TGFß1, MMP-3, MMP-13 and IL-1ß in cartilage and subchondral bone tissues were detected by absolute real-time quantitative RT-PCR. The expression of TGFß1, nestin and osterix in subchondral bone was detected by Western blot analysis and immunohistochemistry. The degree of subchondral bone thickening was determined by micro-computed tomography (CT) imaging. RESULTS: Expression of TGFß1 and cartilage-degrading enzymes was higher in the cartilage-disrupted group than that in the intact group. Furthermore, expression of TGFß1, nestin and osterix was significantly higher in the OA group than that in the control group. Micro-CT imaging showed that in the OA group, the subchondral bone plate is thickened and the density is increased. The trabecular bone structure is thick plate-like structure, the thickness of the trabecular bone is increased and the gap is small. CONCLUSIONS: The data suggest that highly active TGFß1 activates the expression of cartilage-degrading enzymes. Abnormally activated TGFß1 may induce formation of the subchondral bone and expansion of the calcified cartilage area, eventually leading to degradation of the cartilage tissue.

Arthroscopic posterior cruciate ligament (PCL) reconstruction with retention of PCL remnant / 中华创伤杂志

Objective To evaluate the skill and outcome of arthroscopic reconstruction of posterior cruciate ligament (PCL) with retention of PCL remnant. Methods From April 2004 to June 2006, 38 patients (38 knees) with PCL deficiency were verified by clinical and arthroscopic examinations. Of them, there were 9 knees combined with disruption of the posterolateral comer, 6 with rupture of the posteromedial corner, 8 with lateral meniscus tear and 4 with medial meniscus tear. With reservation of PCL remnant and synovium, all the impaired PCLs were reconstructed with single bundle of autogenous quadrupled hamstring tendons under arthroscopy. Interference screws were used for direct anatomic fixation of the reconstructed ligament. Results No severe comphcations occurred at early stage after operation in all 38 patients who were followed up for 12-37 months (average 20.79 months). Lysholm score was improved significandy from 40-70 points (mean 51.32 pints) before operation to 70-100 pints (mean 92.37 points) at the latest follow up (t=-30.14, P<0.01). According to International Knee Documentation Committee (IKDC) score, there was a remarkable improvement from 16 abnormal knees (grade C) and 22 severely abnormal knees (grade D) preoperatively to 18 normal knees ( grade A), 18 nearly normal knees (grade B) and 2 abnormal knees at the latest follow up (Z=-6.00, P <0.01). Of 38 patients, 36 returned to normal sports level but 2 degraded level of sports. Conclusions Arthroscopic PCL reconstruction with retention of PCL remnants is a feasible technique, with satisfactory outcome. Preservation of PCL remnants and synovium may be beneficial to biological incorporation and reinnervation of the reconstructed ligament.