Ping Shang

Histological characteristics of induced membranes in subcutaneous, intramuscular sites and bone defect.

BACKGROUND The induced membrane technique was proposed as a treatment of large segmental bone defects. The influence of the surrounding tissues on its characteristics remains unknown. It is therefore not known which kind of plastic surgery procedure (muscular or facio-cutaneous flap) would optimize bone osteointegration within a bone defect reconstructed using the induced-membrane technique. HYPOTHESIS We hypothesized that membrane characteristics could be influenced by the soft-tissue environment either subcutaneous or muscular. OBJECTIVE To evaluate the histological characteristics of poly-methylmethacrylate (PMMA) induced membranes in intramuscular, subcutaneous and bony environment (radius defects) at 2 steps: spacer implantation; secondary bone graft and its subsequent osteintegration after spacer removal. METHODS PMMA-induced membranes were obtained in the three sites of 15 rabbits. Subsequent new bone formation was studied in the same environments in 24 other rabbits. Six weeks after the initial implantation, PMMA spacers were replaced with iliac autografts. Animals were euthanized at 2, 4, and 8 weeks postoperatively. Tissue samples were harvested and stained with hematoxylin and eosin. The histological characteristics of the membrane (thickness and microvessel density) and the newly-formed bone (cortical thickness) were quantitatively analyzed. RESULTS The membranes in the subcutaneous sites developed quicker, were thicker and had the lowest microvessel density (P<0.01). The membranes in the intramuscular sites developed later and were thinner (P<0.01). The membranes in the osseous defects had the greatest microvessel density (P<0.01). After bone grafting, induced membranes became thinner and their microvessel density decreased substantially, but maintained better in osseous site. The newly-formed bone that developed in the radius defects, had the thickest cortices (P<0.01). CONCLUSIONS The evolution of membranes induced in the intramuscular and subcutaneous environments was close to that of the bone defect model, although bone formation appeared weaker.

Asymmetric Facet Joint Osteoarthritis and its Relationships to Facet Orientation, Facet Tropism and Ligamentum Flavum Thickening.

Study Design:The degrees of osteoarthritis of the left and right facet joints were evaluated by using computerized tomography among elderly patients with low back or leg pain. Objective:To reveal the phenomenon of asymmetry regarding facet joint osteoarthritis (FJOA) in old patients and establish its relationships to spinal level, facet orientation, facet tropism and ligamentum flavum (LF) thickening. Summary of Background Data:There were few reports regarding left-right asymmetry among severity of FJOA and its relationships to spinal level, facet orientation, facet tropism, and LF thickening remained unclear. Methods:The grade of bilateral FJOA was evaluated using 4-grade scale on computerized tomography images at the L3–4, L4–5, and L5–S1 levels of patients with age ranging from 60 to 80 years. All subjects were divided into 2 groups: symmetric FJOA group (FJOA I–II on both sides or FJOA III–IV on both sides) and asymmetric FJOA group (FJOA I–II on one side and FJOA III–IV on the other side). The relationships of FJOA to spinal level, facet orientation, facet tropism, and LF hypertrophy were evaluated. Results:No association between asymmetric FJOA and spinal level was noted (P>0.05). In asymmetric FJOA group, significant difference in facet orientation between 2 sides was observed at the L4–5 (P=0.018) and L5–S1 levels (P=0.033). Compared with symmetric FJOA, asymmetric FJOA showed significant difference in prevalence of facet tropism at the L5–S1 level (P<0.001). The LF showed significantly thicker on the side of FJOA III–IV than the side of FJOA I–II at each level in asymmetric FJOA group (P<0.05). However, no difference was found in thickness between 2 sides in symmetric FJOA group (P>0.05). Conclusions:Asymmetric FJOA is associated with facet orientation and tropism, but not with spinal level. There is a close relationship between severity of FJOA and LF thickness.

The effect of postural correction and subsequent balloon inflation in deformity correction of acute osteoporotic vertebral fractures.

Objective To determine deformity correction by postural correction and subsequent balloon inflation in acute vertebral compression fractures (OVCFs) and to examine the effect of bone mineral density on deformity correction. Methods A totol of 50 acute OVCFs received balloon kyphoplasty. Lateral radiographs were taken and analyzed at five different time points : 1) preoperative, 2) after placing the patient in prone hyperextended position, 3) after balloon inflation, 4) after deposition of the cement, and 5) postoperative. All fractures were analyzed for height restoration of anterior (Ha), middle (Hm) and posterior (Hp) vertebra as well as Cobb angle and Kyphotic angle. The bone mineral density (BMD) of lumbar spine was measured by dual-energy X-ray absorptiometry. According to the T-score, the patients were divided into two groups which were osteoporosis group and osteopenia group. Results Postoperative measurements of Ha, Hm and the Cobb angle demonstrated significant reduction of 4.62 mm, 3.66 mm and 5.34° compared with the preoperative measurements, respectively (each p<0.05). Postural correction significantly increased Ha by 5.51 mm, Hm by 4.35 mm and improved the Cobb angle by 8.32° (each p<0.05). Balloon inflation did not demonstrate a significant improvement of Ha, Hm or the Cobb angle compared with baseline prone hyperextended. Postural correction led to greater improvements of Ha, Hm and Cobb angle in osteoporosis group than osteopenia group (each p<0.05). Conclusion In acute OVCFs, the height restoration was mainly attributed to postural correction rather than deformity correction by balloon inflation. BMD affected deformity correction in the process of postural correction.

Association of osteoarthritis and circulating adiponectin levels: a systematic review and meta-analysis

BackgroundThe objective of this study was to perform a meta-analysis to investigate the specific relationship between the expression level of circulating adiponectin and osteoarthritis (OA).MethodMultiple databases were searched to estimate the high quality of studies relevant to adiponectin and OA. We extracted the data from the eligible studies and included them in the meta-analysis using a random effects model. Subgroup analysis and meta-regression were further performed to explore the potential sources of heterogeneity.ResultsTen articles consisting of thirteen case-control studies that contained a combined total of 1255 subjects. Our results revealed that the OA patients displayed higher adiponectin levels than the healthy controls (SMD = 0.327, 95% CI: 0.11–0.55, P = 0.003). The ethnicity-stratified subgroup analysis indicated that the adiponectin was a sensitive biomarker in both Caucasians (P = 0.021) and Asians (P = 0.037). Moreover, the meta-regression analysis suggested that the sample size (P = 0.03) and nationality (p = 0.01) could account for a part of heterogeneity in our study.ConclusionTaken together, the current study indicated that the adiponectin expression levels were higher in the OA patients than in the healthy controls and might be associated with OA prevalence.

No effectiveness of anticoagulants for thromboprophylaxis after non-major knee arthroscopy: a systemic review and meta-analysis of randomized controlled trials

Arthroscopic knee surgery is the most commonly performed orthopedic procedure worldwide and whether thromboprophylaxis should be undertaken after knee arthroscopy is still controversial. To evaluate the efficacy of thromboprophylaxis for deep venous thrombosis (DVT) and venous thromboembolism (VTE) after knee arthroscopic surgery. A meta-analysis was conducted using data from eight randomized trials (4148 patients) to compare thromboprophylaxis with placebo or no prophylactic treatment in patients undergoing knee arthroscopy. The benefits and harms of thromboprophylaxis were evaluated, including the incidence of asymptomatic DVT, symptomatic VTE, pulmonary embolism and anti-coagulation related adverse events. Thromboprophylaxis significantly decreased the incidence of DVT (95% CI 0.07–0.64, P = 0.006) and symptomatic VTE in patients undergoing knee arthroscopy (95% CI 0.23–0.76, P = 0.004), but not significantly decreased the incidence of pulmonary embolism (n.s.). Regarding to non-major knee arthroscopy surgery (simple surgical procedures without ligament reconstruction), no significant difference of the incidence of DVT or symptomatic VTE was noted between thromboprophylactic group and control group (n.s.). Thromboprophylactic treatment showed higher incidence rate of anti-coagulation related adverse events compared with the control group (95% CI 1.12–1.90, P = 0.005). There was no significant difference of the incidence of clinically relevant major bleeding between the two groups (n.s.). This meta-analysis indicates no effectiveness of thromboprophylaxis for preventing DVT or symptomatic VTE in patients undergoing non-major knee arthroscopy. Regarding to patient undergoing knee ligament construction, the thromboprophylactic strategy should mainly take into account the patient’s risk factors.

Inhibition of Dll4/Notch1 pathway promotes angiogenesis of Masquelet’s induced membrane in rats

The Masquelet’s induced membrane technique for repairing bone defects has been demonstrated to be a promising treatment strategy. Previous studies have shown that the vessel density of induced membrane is decreased in the late stage of membrane formation, which consequently disrupts the bone healing process. However, relatively little is known about certain mechanisms of vessel degeneration in the induced membrane tissue and whether promotion of angiogenesis in induced membranes can improve bone regeneration. Here, we showed that the Delta-like ligand 4/ Notch homolog 1 (Dll4/Notch1) pathway was relatively activated in the late stage of induced membrane, especially at the subcutaneous site. Then, DAPT, a classical γ-secretase inhibitor, was applied to specifically inhibit Notch1 activation, followed by up-regulation of vascular endothelial growth factor receptor 2 (VEGFR2) and CD31 expression. DAPT-modified induced membranes were further confirmed to contribute to bone regeneration after autogenous bone grafting. Finally, in vitro experiments revealed that knocking down Notch1 contributed to the functional improvement of endothelial progenitor cells (EPCs) and that DAPT-treated induced membrane tissue was more favorable for angiogenesis of EPCs compared with the vehicle group. In conclusion, the present findings demonstrate that Dll4/Notch1 signaling is negatively associated with the vessel density of induced membrane. Pharmacological inhibition of Notch1 attenuated the vessel degeneration of induced membrane both in vitro and in vivo, which consequently improved bone formation at the bone defect site and graft resorption at the subcutaneous site.Bone grafts: improving chances of graft acceptanceRepairs to serious bone injuries may be improved by blocking a signaling pathway that causes newly forming membranes to fail. Masquelet’s technique involves placing acrylic spacers in areas of bone damage, inducing the formation of vascularised membranes which encourage the body to accept bone grafts. However, sometimes Masquelet’s membranes do not form correctly, leading to weaknesses in bone repairs and potential graft rejection. In experiments on rats, Qian Tang from Wenzhou Medical University, China, and coworkers found that a particular signaling pathway, D114/Notch1, was upregulated around 6 weeks post-operation, reducing blood vessel density and limiting new vessel growth, weakening the membranes. The team inhibited this pathway using an existing therapy that prevents blood clots. This treatment improved bone repairs by promoting the formation and function of blood vessels in membranes.

Extramedullary versus intramedullary femoral alignment technique in total knee arthroplasty: a meta-analysis of randomized controlled trials

BackgroundThere is no consensus whether the use of the extramedullary femoral cutting guide takes advantage over the intramedullary one in total knee arthroplasty. The aim of this study was to compare the extramedullary femoral alignment guide system with the conventional intramedullary alignment guide system for lower limb alignment, blood loss, and operative time during total knee arthroplasty.MethodsThe Medline, Embase, Cochrane Library, China National Knowledge Infrastructure (CNKI), Wan Fang Chinese Periodical, Google, and reference lists of all the included studies were searched for randomized controlled trials. The following parameters were compared between the extramedullary technique and the intramedullary technique: (1) lower limb coronal alignment, (2) coronal alignment of femoral component, (3) sagittal alignment of femoral component, (4) blood loss, (5) and operation time.ResultsFour randomized controlled trials consisting of 358 knees were included in our study. There was no significant difference between the extramedullary and intramedullary groups for the lower limb coronal alignment (RR = 1.20, 95%CI 0.28~5.21, n.s.), coronal alignment of femoral component (RR = 0.65, 95%CI 0.19~2.22, n.s.), and sagittal alignment of femoral component (RR = 0.73, 95%CI 0.38~1.41, n.s.). A reduced blood loss was associated with the use of the extramedullary guide (MD = −120.34, 95%CI −210.08~−30.59, P = 0.009). No significant difference in operation time was noted between the two groups (MD = 1.41, 95%CI −1.82~4.64, n.s.).ConclusionsNeither extramedullary nor intramedullary femoral alignment is more accurate than the other in facilitating the femoral cut in total knee arthroplasty. Use of the extramedullary guide results in less blood loss and exhibits a similar operation time as compared with the intramedullary guide.