Effect of PCL integrity on biomechanical features of the medial femoral condyle / 中华骨科杂志

Objective To explore the biomechanical function of PCL and its different bundles and examine the biomechanical impact of posterior cruciate ligament (PCL) integrity on the medial femoral condyle. Methods Twelve fresh human cadaveric knee specimens were subjected to different axial load (0-800 N) at 0°, 30°,60°, and 90°of knee flexion. Four surgical treatments were carried out for biomechanical testing: PCL intact, anterolateral bundle (ALB) rupture, posteromedial bundle (PMB) rupture and PCL rupure. During the test, strains of middle part of the medial femoral condyle were calculated. Results At O°knee flexion, increasing strain of the medial femoral condyle was detected in PMB rupture and PCL rupture under all loading conditions. No significant difference of strain of the medial femoral condyle was noted between PCL intact and ALB rupture under any loading conditions. Compared to PMB rupture, PCL rupture had not higher strain of the medial femoral condyle under all loading conditions. At 30°, 60° and 90° knee flexion, increasing strain of the medial femoral condyle was noted in ALB rupture under higher loading conditions and PCL rupture under all loading conditions. ALB rupture under lower loading conditions and PMB rupture under all loading conditions did not significantly increased strain of the medial femoral condyle. PCL rupture had higher strain of the medial femoral condyle than ALB rupture under most of loading conditions.Conclusion The data suggest that PMB is the major stabilizing bundle of PCL in full extension, ALB is the major stabilizing bundle of PCL in knee flexion, and both bundles function through the ROM in a codominant fashion. Partial and complete ruptures of PCL may have hazardous biomechanical impacts on the medial femoral condyle during normal movement.

Correlation of synovial fluid and articular cartilage osteopontin with disease severity in knee osteoarthritis / 中华骨科杂志

Objective To examine osteopontin (OPN) levels in both synovial fluid and articular cartilage of patients with primary knee osteoarthritis (OA) and to investigate their relationship with severity of the disease. Methods Fifty patients with knee OA and 10 healthy controls were enrolled in this study.There were 15 males and 35 females with an average age of 61.8±7.4 years in OA group. The control group included 4 males and 6 females with an average age of 63.2±6.0 years. Mankin score were taken to determine the disease severity of the affected knee. The radiographic grading of OA in the knee was performed using the Kellgren-Lawrence criteria. OPN levels in synovial fluid were measured using enzyme-linked immunosorbent assay. OPN levels in articular cartilage were assessed by immunohistochemical methods. Results Compared to healthy controls, the knee OA patients had higher OPN concentration in synovial fluid ([4519.60±1830.37] pg/ml vs. [1179.70±303.39] pg/ml) and articular cartilage([0.60±0.06] vs. [0.43 ±0.07]). In addition, synovial fluid OPN levels showed a positive correlation with articular cartilage OPN levels (r=0.411,P=0.003). Subsequent analysis showed that the OPN levels in synovial fluid significantly had been correlated with severity of disease using Kellgren-Lawrence criteria (r=0.581, P＜ 0.001). Furthermore,the levels of OPN in the articular cartilage also were correlated with disease severity using Mankin score (r=0.675, P＜ 0.001).Conclusion The data suggest that OPN in synovial fluid and articular cartilage is related to progressive joint damage and could be a predictive biomarker respect to disease severity and progression in knee OA.