Kanghua Li

Elevated osteopontin level of synovial fluid and articular cartilage is associated with disease severity in knee osteoarthritis patients

OBJECTIVE To investigate osteopontin (OPN) levels in both synovial fluid and articular cartilage of patients with primary knee osteoarthritis (OA) and their relationship with severity of the disease. METHOD Fifty patients aged 48-81 years with knee OA and 10 healthy controls were enrolled in this study. Anteroposterior knee radiographs or/and Mankin score were taken to determine the disease severity of the affected knee. The radiographic grading of OA in the knee was performed by 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, OA patients had higher OPN concentration in synovial fluid (4519.60+/-1830.37, 95%CI 3999.42-5039.79 vs 1179.70+/-303.39, 95%CI 1035.53-1438.74 pg/ml, P<0.001)and articular cartilage(0.6+/-0.06, 95%CI 0.59-0.62 vs 0.43+/-0.07, 95%CI 0.38-0.48, P<0.01). In addition, synovial fluid OPN levels showed a positive correlation with articular cartilage OPN levels (r=0.411, 95%CI 0.150-0.619, P=0.003). Subsequent analysis showed that synovial fluid OPN levels significantly correlated with severity of disease (Spearmans rho=0.581, 95%CI 0.335-0.726, P<0.001). Furthermore, the articular cartilage levels of OPN also correlated with disease severity (Spearmans rho=0.675, 95%CI 0.500-0.808, P<0.001). CONCLUSIONS OPN in synovial fluid and articular cartilage is associated with progressive joint damage and is likely to be a useful biomarker for determining disease severity and progression in knee OA.

Bone turnover in passive smoking female rat: relationships to change in bone mineral density

BackgroundMany studies have identified smoking as a risk factor for osteoporosis, but it is unclear whether passive smoking has an effect on bone mineral density and bone turnover and if such an effect could cause osteoporosis.The purpose of the study was to investigate the effect of passive smoking on bone mineral density (BMD) and bone turnover and the relationship between BMD and bone turnover in female rat.MethodsForty-eight female Wistar rats were randomized into six groups: 2-month, 3-month,4-month smoke-exposed rats and their controls. A rat model of passive cigarette smoking was prepared by breeding female rats in a cigarette-smoking box for 2, 3 or 4 months. Serums were analyzed for levels of osteocalcin, bone-specific alkaline phosphatase (b-ALP) and Tartrate-resistant acid phosphatase 5b (TRACP 5b). BMD was assessed at lumbar vertebrae and femur by dual energy X-ray absorptiometry in passive smoking rats and in control rats.ResultsBMD of lumbar spine and femur was lower in 4-month smoke-exposed female rats than that in controls. However, there was no significant difference in serum osteocalcin levels between smoke-exposed rats and controls. Significantly lower b-ALP and higher TRACP 5b were found in the 3-month or 4-month smoke-exposed rats compared to controls. Subsequent analysis showed that b-ALP positively correlated with BMD of the lumbar vertebrae(r = 0.764, P = 0.027) and femur(r = 0.899, P = 0.002) in 4-month smoke-exposed female rats. Furthermore, TRACP 5b levels negatively correlated with BMD of lumbar vertebrae (r = -0.871, P = 0.005) and femur (r = -0.715, P = 0.046) in 4-month smoke-exposed female rats.ConclusionOur data suggest that smoke exposure can inhibit bone formation and increase bone resorption. The hazardous effects of passive smoking on bone status are associated with increased bone turnover in female rat.

Biomechanical evaluation of tenodesis reconstruction in ankle with deltoid ligament deficiency: a finite element analysis

PurposeIsolated deltoid ligament injuries are relatively uncommon but can be a significant source of pain and disability. Several approaches to deltoid reconstruction have been reported. However, there is no previous comparative study of Wiltberger, Deland, Kitaoka and Hintermann procedures with respect to biomechanical characteristics such as kinematics, ligaments and grafts stresses using finite element analysis. The purpose of this study was to evaluate the biomechanical results of those deltoid ligament reconstructions using finite element analysis.MethodsA three-dimensional finite element model of the ankle including six bony structures, cartilage and nine principal ligaments surrounding the ankle joint complex was developed and validated. In addition to the intact model, superficial deltoid-deficient, deltoid-deficient, Wiltberger reconstruction, Deland reconstruction, Kitaoka reconstruction and Hintermann reconstruction models were simulated. Then, the forces in the ligaments and grafts and the kinematics of talus and calcaneus were predicted for an eversional or external torque through the range of ankle flexion.ResultsNo reconstructions could completely restore the values for ankle flexibility and the stresses of the lateral ligaments to normality. The Kitaoka procedure was the most effective technique in eliminating external rotation displacement. The Deland procedure restored better the talar tilt than the other three reconstructions.ConclusionThis study showed that Kitaoka and Deland procedures have advantages with regard to rotational stabilities as well as ligaments stress in comparison with other methods.

Effect of epimedium pubescen flavonoid on bone mineral status and bone turnover in male rats chronically exposed to cigarette smoke

BackgroundEpimedii herba is one of the most frequently used herbs in formulas that are prescribed for the treatment of osteoporosis in China and its main constituent is Epimedium pubescen flavonoid (EPF). However, it is unclear whether EPF during chronic exposure to cigarette smoke may have a protective influence on the skeleton. The present study investigated the effect of EPF on bone mineral status and bone turnover in a rat model of human relatively high exposure to cigarette smoke.MethodsFifty male Wistar rats were randomized into five groups: controls, passive smoking groups and passive smoking rats administered EPF at three dosage levels (75, 150 or 300 mg/kg/day) in drinking water for 4 months. A rat model of passive smoking was prepared by breeding male rats in a cigarette-smoking box. Bone mineral content (BMC), bone mineral density (BMD), bone turnover markers, bone histomorphometric parameters and biomechanical properties were examined.ResultsSmoke exposure decreased BMC and BMD, increased bone turnover (inhibited bone formation and stimulated its resorption), affected bone histomorphometry (increased trabecular separation and osteoclast surface per bone surface; decreased trabecular bone volume, trabecular thickness, trabecular number, cortical thickness, bone formation rate and osteoblast surface per bone surface), and reduced mechanical properties. EPF supplementation during cigarette smoke exposure prevented smoke-induced changes in bone mineral status and bone turnover.ConclusionThe results suggest that EPF can prevent the adverse effects of smoke exposure on bone by stimulating bone formation and inhibiting bone turnover and bone resorption.

Biomechanical comparison of lumbar total disc arthroplasty, discectomy, and fusion: effect on adjacent-level disc pressure and facet joint force

OBJECT With the increasing advocacy for total disc replacement (TDR) as a potential alternative to fusion in the management of lumbar degenerative disc disease, intradiscal pressures (IDPs) and facet joint stresses at the adjacent levels of spine have generated considerable interest. The purpose of this study was to compare adjacent-level IDPs and facet joint stresses among TDR, discectomy, and fusion. METHODS Ten fresh human cadaveric lumbar specimens (L2-S1) were subjected to an unconstrained load in axial torsion, lateral bending, flexion, and extension by using multidirectional flexibility test. Four surgical treatment modes-control (disc intact), discectomy, TDR, and fusion-were tested in sequential order at L4-5. During testing, the IDPs and facet forces following each treatment were calculated at the adjacent vertebral levels (L3-4 and L5-S1). RESULTS Intradiscal pressures and facet force pressures were similar between the intact condition and the TDR reconstruction at the L3-4 and L5-S1 levels under all loading conditions (p > 0.05). Compared with the intact and TDR groups, the discectomy and fusion groups had higher IDPs at the L3-4 and L5-S1 levels under all loading conditions (p < 0.05). No significant difference in the facet force pressure was noted among the intact, discectomy, and TDR groups at the L3-4 and L5-S1 levels under any loading conditions (p > 0.05). However, the facet force pressure produced for fusion was significantly higher than the mean values obtained for the intact, discectomy, and TDR groups at the L3-4 and L5-S1 levels under all loading conditions (p < 0.05). CONCLUSIONS Lumbar TDR maintained adjacent-level IDPs and facet force pressures near the values for intact spines, whereas adjacent-level IDPs tended to increase after discectomy or fusion and facet forces tended to increase after fusion.

Tenuigenin inhibits RANKL-induced osteoclastogenesis by down-regulating NF-κB activation and suppresses bone loss in vivo

Tenuigenin, a major active component of polygala tenuifolia root, has been used to treat patients with insomnia, dementia, and neurosis. In this study, we aimed to investigate the effects of tenuigenin on osteoclastogenesis and clarify the possible mechanism. We showed that tenuigenin inhibited receptor activator of nuclear factor-κB ligand (RANKL)-induced osteoclast differentiation and bone resorption without cytotoxicity, which was further demonstrated by reduced osteoclast specific gene expression such as TRAP, c-Src, ATP6v0d2, etc. Moreover, the inhibitory effect of tenuigenin was associated with impaired NF-κB activity owing to delayed degradation/regeneration of IkBa and inhibition of p65 nuclear translocation. Consistent with the in vitro results, micro-ct scanning and analysis data showed that tenuigenin suppressed RANKL-induced bone loss in an animal model. Taken together, our data demonstrate that tenuigenin inhibit osteoclast formation and bone resorption both in vitro and in vivo, and comprise a potential therapeutic alternative for osteoclast-related disorders such as osteoporosis and cancer-induced bone destruction.

Effect of partial and complete posterior cruciate ligament transection on medial meniscus: A biomechanical evaluation in a cadaveric model

Background: The relationship between medial meniscus tear and posterior cruciate ligament (PCL) injury has not been exactly explained. We studied to investigate the biomechanical effect of partial and complete PCL transection on different parts of medial meniscus at different flexion angles under static loading conditions. Materials and Methods: Twelve fresh human cadaveric knee specimens were divided into four groups: PCL intact (PCL-I), anterolateral bundle transection (ALB-T), posteromedial bundle transection (PMB-T) and PCL complete transection (PCL-T) group. Strain on the anterior horn, body part and posterior horn of medial meniscus were measured under different axial compressive tibial loads (200-800 N) at 0°, 30°, 60° and 90° knee flexion in each groups respectively. Results: Compared with the PCL-I group, the PCL-T group had a higher strain on whole medial meniscus at 30°, 60° and 90° flexion in all loading conditions and at 0° flexion with 400, 600 and 800 N loads. In ALB-T group, strain on whole meniscus increased at 30°, 60° and 90° flexion under all loading conditions and at 0° flexion with 800 N only. PMB-T exihibited higher strain at 0° flexion with 400 N, 600 N and 800 N, while at 30° and 60° flexion with 800 N and at 90° flexion under all loading conditions. Conclusions: Partial PCL transection triggers strain concentration on medial meniscus and the effect is more pronounced with higher loading conditions at higher flexion angles.

Impact of Partial and complete rupture of anterior cruciate ligament on medial meniscus: A cadavaric study

Background: The clinical relationship between medial meniscus tear and anterior cruciate ligament (ACL) rupture has been well documented. However, the mechanism of this clinical phenomenon is not exactly explained. Our aim is to investigate the biomechanical impact of partial and complete ACL rupture on different parts of medial meniscus. Materials and Methods: Twelve fresh human cadaveric knee specimens were divided into four groups: ACL intact (ACL-I), anteromedial bundle transection (AMB-T), posterolateral bundle transection (PLB-T), and ACL complete transection (ACL-T) group. Strain on the anterior horn, body part, and posterior horn of medial meniscus were measured under 200 N axial compressive tibial load at 0°, 30°, 60°, and 90° of knee flexion, respectively. Results: Compared with the control group (ACL-I), the ACL-T group had a higher strain on whole medial meniscus at 0°, 60°, and 90° of flexion. But at 30°, it had a higher strain on posterior horn of meniscus only. As to PLB-T group, strain on whole meniscus increased at full extension, while strain increased on posterior horn at 30° and on body of meniscus at 60°. However, AMB-T only brought about higher strain at 60° of flexion on body and posterior horn of meniscus. Conclusions: Similar to complete rupture, partial rupture of ACL can also trigger strain concentration on medial meniscus, especially posterior horn, which may be a more critical reason for meniscus injury associated with chronic ACL deficiency.

Finite Element Analysis of Nonanatomic Tenodesis Reconstruction Methods of Combined Anterior Talofibular Ligament and Calcaneofibular Ligament Deficiency

Background: Nonanatomic tenodesis reconstruction procedures have been used for lateral ankle ligament reconstruction. However, there has been no comparison of Watson-Jones, Evans, and Chrisman-Snook procedures with respect to biomechanical characteristics such as kinematics, ligaments and grafts stresses using finite element analysis. Methods: A three-dimensional finite element model of the ankle including seven bony structures, cartilage and nine principal ligaments surrounding the ankle joint complex was developed and validated. In addition to the intact model, combined anterior talofibular ligament (ATFL) and calcaneofibular ligament (CFL) deficient, Watson-Jones reconstruction, Evans reconstruction and Chrisman-Snook reconstruction models were simulated. Then, the forces in the ligaments and grafts and the kinematics of the talus and calcaneus were predicted for an inversion or internal torque of 1.7 N•m and an anterior drawer stress of 150 N through the range of ankle motion. Results: All three operations were able to improve the stability of the ankle, but the effectiveness of each procedure was dependent on the direction of the stress applied and the position of the ankle in dorsiflexion-plantarflexion. Conclusion: This study showed that the Watson-Jones procedure has advantages with regard to anterior and rotational stabilities as well as ligaments and grafts stresses in comparison with other nonanatomic tenodesis reconstruction methods. Clinical Relevance: The knowledge of stress inside the ligaments and reconstructed grafts could help to better understand the biomechanical behavior of the reconstructed joint.

Effect of posterior cruciate ligament rupture on the radial displacement of lateral meniscus

BACKGROUND The relationship between lateral meniscus tear and posterior cruciate ligament injury is not well understood. The present study aims to investigate and assess the effect of posterior cruciate ligament rupture on lateral meniscus radial displacement at different flexion angles under static loading conditions. METHODS Twelve fresh human cadaveric knee specimens were divided into four groups such as posterior cruciate ligament intact, anterolateral band rupture, posteromedial band rupture and posterior cruciate ligament complete rupture groups, according to the purpose and order of testing. Radial displacement of lateral meniscus was measured under different loads (200-1000N) at 0°, 30°, 60°, and 90° of knee flexion. FINDINGS Compared with posterior cruciate ligament intact group, the displacement values of lateral meniscus in anterolateral band rupture group increased at 0° flexion with 600N, 800N, and 1000N and at 30°, 60° and 90° flexion under all loading conditions. Posteromedial band rupture group exhibited higher displacement at 0° flexion under all loading conditions, at 30° and 60° flexion with 600, 800N and 1000N, and at 90° flexion with 400N, 600N, 800N, and 1000N than the posterior cruciate ligament intact group. The posterior cruciate ligament complete rupture group had a higher displacement value of lateral medial meniscus at 0°, 30°, 60° and 90° flexion under all loading conditions, as compared to the posterior cruciate ligament intact group. INTERPRETATION The study concludes that partial and complete rupture of the posterior cruciate ligament can trigger the increase of radial displacement on lateral meniscus.