Biomechanical analysis of a lacunar-canalicular system under different cyclic displacement loading.

The objective of this study is to use the finite element (FE) method to predict the mechanical signals (interstitial fluid velocity, strain, pore pressure, and pore fluid velocity) produced by osteocyte during physiological activities. The model predicts that the amplitude and distribution of the mechanical signals are mainly affected by the loading rate. The magnitude of mechanical signals in the lacunar-canalicular system increases as the amplitude, frequency and amount of direction of load increase. Collagen hillocks can effectively amplify strain signals at the process. The established model can be used for studying the mechanism of bone mechanotransduction at the micro-level.

Layered mechanical and electrical properties of porcine articular cartilage.

The complex structure and composition of articular cartilage make its performance show depth-dependent characteristics, but its related parameters are not complete at present. In this study, porcine articular cartilage was divided into three zones along the thickness direction, and the cartilage tissue in each zone was tested for electrical impedance, compression relaxation, and permeability to obtain their mechanical and electrical impedance parameters. The results showed that there were significant differences in mechanical and electrical properties of cartilage tissue in different zones in which resistivity, elastic modulus, relaxation time, and final relaxation rate increased gradually from superficial zone to deep zone along the direction of cartilage thickness while the permeability decreased gradually. Bioimpedance analysis can capture the phenomenon of very slight histological changes, which is expected to provide information for predicting cartilage degeneration, but the electrical impedance parameters of cartilage are still very lacking. These data are expected to provide reference for the treatment of clinical osteoarthritis and the research of cartilage repair materials.

Study on the poroelastic behaviors of the defected articular cartilage.

This article presented the possible mechanism of arthritis damaged changes in cartilage's interstitial fluid flowing behavior. Firstly, the analytical solutions for the pore fluid pressure and velocity in the idealized cartilage defect model were obtained, which are employed to validate the finite element (FE) method. Then according to the MRI data, an articular cartilage FE model was developed to study the effects of defect characteristics on its poroelastic behaviors. The results showed the interstitial fluid pressure and velocity in defected articular cartilage is diminished, moreover, this trend is even more severe as the defect radius or thickness increased. As the development of osteoarthritis goes, the fluid velocity is decreased and cause the even serious nutrients loss.

Local Infiltration Analgesia Versus Regional Blockade for Postoperative Analgesia in Total Knee Arthroplasty: A Meta-analysis of Randomized Controlled Trials.

BACKGROUND: Total knee arthroplasty (TKA) is one of the most commonly performed procedures while postoperative analgesia still remains challenging. The efficacy and safety of local infiltration analgesia (LIA) versus regional blockade (RB; epidural analgesia and/or peripheral nerve block) for pain management after TKA are controversial. OBJECTIVES: The purpose of this meta-analysis was to determine whether LIA compared with RB would provide better postoperative pain control, consume less morphine, facilitate early functional recovery, entail a differential risk of side effects and complications, and allow a shorter length of stay. STUDY DESIGN: This meta-analysis pooled all data published in randomized controlled trials (RCTs) examining the efficacy and safety of LIA versus RB following TKA. SETTING: The work was performed at Affiliated Cixi Hospital, Wenzhou Medical University. METHODS: Literature in English was searched using EMBASE, Medline, Cochrane Library, CINAHL, Web of Science, and Scopus from inception to April 2015. RCTs that compared LIA and RB for postoperative analgesia following TKA were included. Methodological quality was assessed using the Cochrane Back Review Group checklist, and a sensitivity analysis was performed. Sixteen RCTs with a total of 1,206 patients were finally included in our study. RESULTS: The results of our meta-analysis indicate that patients managed by LIA showed significantly lower numeric rating scale (NRS) score at rest (WMD: -0.40 [-0.72, -0.07]; P = 0.02) when compared with those managed by RB. Difference of morphine consumption was not significant (WMD: -1.39 [-7.21, 4.44]; P = 0.64) between the 2 groups. In terms of early functional recovery, the LIA group showed more straight leg raise (RR: 2.90 [2.15, 3.93]; P < 0.00001) on the first postoperative day; better range of motion within one week (WMD: 4.33 [2.61, 6.05]; P < 0.00001), but not at 3 months (WMD: 1.98 [-0.02, 3.98]; P = 0.05); and comparable knee society score (WMD: -8.79 [-27.05, 9.48]; P = 0.35). Length of hospital stay of the LIA group was marginally shorter (WMD: -0.25 [-0.49, -0.01]; P = 0.05) than that of the RB group. Risk of side effects and complications were comparable between groups. LIMITATIONS: The lack of a standard criterion regarding the technique details of LIA and heterogeneity resulting from the various analgesic components, dosages, and different administration methods might have posed a bias on the results. CONCLUSION: Our results have indicated that LIA provided better analgesia than RB at rest and preserved quadriceps function in the immediate postoperative period, which may be beneficial to early functional recovery. And its safety profile is reliable. With the biases in our meta-analysis, a rigorous and adequately powered RCT is needed to validate our results. KEY WORDS: Local infiltration analgesia, regional block, peripheral nerve block, epidural analgesia, postoperative analgesia, total knee arthroplasty, meta-analysis, randomized controlled trial.

[Case control study on open reduction internal fixation (ORIF) and minimally invasive percutaneous plate osteosynthesis (MIPPO) for the treatment of proximal humerus fractures in aged].

OBJECTIVE: To investigate the clinical effects of close reduction and minimally invasive percutaneous plate osteosynthesis in treating proximal humerus fractures in the aged. METHODS: From February 2012 to December 2013,39 patients with proximal humerus fractures were treated with minimally invasive percutaneous plate osteosynthesis (MIPPO group, 21 cases) and open reduction internal fixation (ORIF group, 18 cases). Including 17 males and 22 females in the study, and aged from 67 to 88 years old with an average of (71.8 ± 5.2) years old. In MIPPO group, there were 11 males and 10 females with an average age of (70.0 ± 5.3) years old;and in ORIF group, there were 10 males and 8 females with an average age of (72.0 ± 4.2) years old. Operation time, blood loss during operation, fracture healing time and postoperative complications were recorded. The functions of the shoulder joints were assessed according to Constant-Murley score at final follow-up. RESULTS: All the patients were followed up from 11 to 27 months with an average of 18.1 months. The mean blood loss of the MIPPO group was (176.0 ± 57.4) ml,while the ORIF group was (356.0 ± 66.9) ml (t = 7.22,P = 0.01). The operation time of the MIPPO group was (47.4 ± 14.9) min, while the ORIF group was (92.7 ± 15.8) min (t = 0.79, P = 0.03). Fracture healing time in the MIPPO group and ORIF group was (17.6 ± 5.8), ( 21.7 ± 4.9) weeks, respectively (P < 0.05). The mean Constant-Murley score at final follow-up was 89.7 ± 14.5 in MIPPO group, and 81.8 ± 13.2 in ORIF group (P < 0.05). CONCLUSION: MIPPO has advantages of little trauma, less blood loss, rapid recovery, less vascular damage and so on and can effectively treat the proximal humerus fracture in the aged.

[Myogenic elephant skin cream combined with Vacuum sealing drainage (VSD) for the treatment of bedsores].

OBJECTIVE: To discuss the efficacy of the myogenic elephant skin cream combining with VSD for treating severe bedsores. METHODS: Twenty-nine cases of III and IV degree bedsores were treated from June 2009 to June 2013. Among them, 15 cases were treated by myogenic elephant skin cream combined with VSD (VSD group) including 7 males and 8 females with an average age of (69.0±5.3) years old ranging from 17 to 96 years;other 14 cases were treated by the treatment of conventional dressing change (control group) including 6 males and 8 females with an average age of (71.0±4.2) years old ranging from 40 to 86 years. At 7, 14, 21, 28 d after treatments, specimens of wound two groups were respectively taken to examine immunohistochemical CD34 adopted SABC, the number of wild vascular cross were observed as capillary density value under high magnification microscope. It was used to assess the hyperplasia of granulation tissue of wound. The capillary density value and the visual wound observation were indicators for evaluation of clinical efficacy. RESULTS: Seventeen of 19 cases got complete data of specimens of wound at 7, 14, 21, 28 d,included 9 cases of VSD group,8 of control group. In the microscope view, the capillary density of VSD group was higher than that of control group significantly (P<0.05), it showed the application of VSD technology improved hyperplasia of granulation tissue much faster than conventional dressing change. In VSD group, 13 cases with 15 wounds healed, 2 cases with 3 wounds improved; in control group,3 cases with 3 wounds healed,7 cases with 9 wounds improved, 4 cases with 5 wounds were unhealed. CONCLUSION: Using the VSD technology with continuous high pressure suction to clean the drainage of wound and lacuna thoroughly can effectively control infection,promote the growth of granulation tissue, and then applying myogenic elephant skin cream to improve partial blood supply while prompting rapid growth of new granulation tissue and epithelial cell. The risk of this treatment is low,and the course of treatment is short, this provides a safe and effective method for treating bedsores.