We hypothesised that diet-induced obesity (DIO) would result in inferior enthesis healing in a rat model of rotator cuff (RC) repair and that dietary intervention in the peri-operative period would improve enthesis healing. A total of 78 male Sprague-Dawley rats were divided into three weight-matched groups from weaning and fed either: control diet (CD), high-fat diet (HFD), or HFD until surgery, then CD thereafter (HF-CD). After 12 weeks, the left supraspinatus tendon was detached, followed by immediate surgical repair. At 2 and 12 weeks post-surgery, animals were culled, and RCs harvested for biomechanical and histological evaluation. Body composition and metabolic markers were assessed via DEXA and plasma analyses, respectively. DIO was established in the HFD and HF-CD groups before surgery and subsequently reversed in the HF-CD group after surgery. Histologically, the appearance of the repaired entheses was poorer in both the HFD and HF-CD groups compared with the CD group at 12 weeks after surgery, with semiquantitative scores of 6.2 (P<0.01), 4.98 (P<0.01), and 8.7 of 15, respectively. The repaired entheses in the HF-CD group had a significantly lower load to failure (P=0.03) at 12 weeks after surgery compared with the CD group, while the load to failure in the HFD group was low but not significantly different (P=0.10). Plasma leptin were negatively correlated with histology scores and load to failure at 12 weeks after surgery. DIO impaired enthesis healing in this rat RC repair model, with inferior biomechanical and histological outcomes. Restoring normal weight with dietary change after surgery did not improve healing outcomes. Circulating levels of leptin significantly correlated with poor healing outcomes. This pre-clinical rodent model demonstrates that obesity is a potentially modifiable factor that impairs RC healing and increases the risk of failure after RC surgery

Thigh-calf contact force is the force acting on posterior side of the thigh and calf during deep knee flexion. It has been reported the force is important to analyze the kinetics of a lower limb and a knee joint. Some previous researches reported the measured thigh-calf contact force, however, the values varied among the reports. Furthermore, the reports indicated that there were large variations even in a single report. One of the reports tried to find the relationship between the magnitude of thigh-calf contact force and anthropometric measurement as height, weight or perimeter of the lower limb, however, there could not found clear correlations. We considered that the cause of the variations might be the difference of the posture. At heel-rise squatting posture, we can bend or stand upright the upper body. Therefore we tried to create the equation to estimate the thigh-calf contact force by multiple regression analysis, using the anthropometric and posture parameters as explanatory variables. We performed the experiment to measure thigh-calf contact force, joint angles and anthropometric information. Test subjects were 10 healthy male. First we measured their height, weight, perimeter of the thigh and muscle mass of the legs and whole body. Muscle mass was measured by body composition meter (BC-118E, Tanita Co., Japan). Then, test subjects were asked to squat with their heels lifted and with putting the pressure distribution sensor between thigh and calf. And they bent their upper body forward and backward. The pressure sensor to be used was ConfroMat System (Nitta Co., Japan). After that, we measured the joint angles of the hip, knee and ankle, and the angle between the floor and upper body using the videos taken during the experiment. Then, we created the equation to estimate the thigh-calf contact force by linear combination of the anthropometric values and joint angles. The coefficients were settled as to minimize the average error between measured and estimated values. Results are shown in Fig.1. Forces were normalized by the body weight of the test subjects. Because the horizontal axes show the measured and vertical axis show the estimated values, the estimation is accurate when the plots are near the 45-degree line. Average error was 0.11BW by using only physical values, 0.15BW by angles and 0.06BW using both values. And the maximum error was 0.69BW, 0.43BW and 0.32BW respectively. Thus we could estimate the thigh-calf contact force by multiple regressions, using both physical parameters and angles to indicate the posture. Using the equation, we would be able to analyze the kinetics of a lower limb by physical and motion measurement. Our future work might be increasing the number of subjects to consider the appropriateness, because the test subjects of this study were very limited

Introduction. Total knee arthroplasty [TKA] is a common procedure to relieve painful disability from advanced knee arthritis. However, related blood loss, ranging from 800 to 1200 ml, increase risk and disruption of recovery in anemic patients following TKA. Various methods for blood conservation had been proposed and examined. In the literature, the intra-articular administration of a solution mixing bupivacaine and epinephrine was commonly used after knee surgeries. Therefore, we conducted a retrospective, case controlled review of our primary TKAs to determine the hemostatic efficacy of this regimen following TKAs. Material and Methods. Over a period of 12 months, 135 eligible patients were divided two groups simply according to the intra-articular injection or not: a control group (N=63) and a treatment group (N=72). In the treatment group, a 40 ml vial of 0.5% bupivacaine with epinephrine 1: 200000 was given prior to the deflation of pneumatic tourniquet. No drainage was used in all TKAs. Without recordable drainage, a Gross formula, considering gender and body composition, was used for estimate blood loss following TKAs. In addition, serial changes in hemoglobin as well as the requirement of allogenic transfusion were also compared between groups. Results. The mean calculated blood loss in the treatment group was 650.4 +/− 257.1 ml, compared to 648.8+/− 222.1 ml in the control group (p=0.9). Similar decrease in hemoglobin as well as rates of allogenic transfusion needs were observed between groups.[2.5+/− 0.9 g/dl vs. 2.4+/− 0.8 g/dl; 13.9% vs. 12.7%, respectively]. Discussion and Conclusion. Although local analgesics mixing vasoconstrictive agents seem a logic solution to save blood loss and relieve pain simultaneously, the hypothesis that intra-articular injection of bupivacaine and epinephrine would save blood and even transfusion needs following TKAs is not supported by various bleeding parameters in this study. In addition to temporary benefit in pain relief, this regimen only has little effect on blood conservation. Therefore, new regimen as well as hemostatic means are still required and explored to reduce blood loss following TKAs