Rotator cuff tears is a common cause of debilitating pain, reduced shoulder function, and weakness.Although the research progress for rotator cuff tear and surgical treatment has made great progress, rotator cuff repair failure rate still was ranged from 20 to 90%.Therefore it need new repair materials which can effectively improve the mechanical strength and stimulateg the intrinsic healing potential of the patient.In recent years, biological scaffolds used in rotator cuff repair has become a hotspot.This paper reviews the progress of scaffold materials on the treatment of rotator cuff injury.

Free fatty acids generated from the metabolites of fat have been demonstrated to stimulate the neutrophils to produce reactive oxygen species ( ROS) such as hydrogen peroxide and chlorous peroxide .It has shown that free fatty acid is closely related with myocardial, vascular endothelium, liver, lung and other tissue damage.The mechanism of erythrocyte injury is oxidation of mem-brane polyunsaturated fatty acids and cytosolic hemoglobin by ROS .High levels of free fatty acids can increase the formation of active reaction molecular ROS , thus initiating the oxidative stress reaction .Active molecules can oxalate and damage the DNA , protein, lipid and other molecules of RBC .It has revealed the relationship between free fatty acids and erythrocytes injury , which provided a new di-rection in the research of oxidative anemia .This article reviews the advances in the research of this subject in recent years .

BACKGROUND:Hidden blood loss leads to severe anemia after orthopedic joint arthroplasty.Blood transfusion is needed.Use of tranexamic acid can significantly decrease perioperative blood loss,reduce blood transfusion rate,however,mechanism of action of tranexamic acid on hidden blood loss and its relevance are not clear.OBJECTIVE:By establishing the rabbit models of total knee prosthesis,this study was designed to observe thevariation of early preoperative blood loss with tranexamic acid,and to study the effects of tranexamic acid on hidden blood loss and its influence on deep venous thrombosis of lower limb.METHODS: We designed the rabbit knee prosthesis ourselves.A total of 20 adult New Zealand rabbits were randomly divided into two groups,each group with 10 rabbits.Knee arthroplasty on the same side was performed.Experimental group received intravenous injection of 0.5 g 100 mL tranexamic acid at 15 minutes before replacement.Control group was given 100 mL sodium chloride at the same time.Blood was colected from al animals through ear vein at 1 day before replacement,3,6,24,48,72 hours and 7 days after replacement.Blood routine examination and blood coagulation function test were conducted.The content of plasma D-Dimer was determined.Simultaneously,the operation time and intraoperative bleeding amount were recorded.After replacement,lower limb venous ultrasonography was performed.RESULTS AND CONCLUSION: No significant difference in body weight,hemoglobin,hematocrit,and D-Dimer levels was detected between the two groups before replacement (P＞0.05).Significant differences in operation time and intraoperative dominant blood loss were detectable between the two groups (P＜0.05).Significant differences in hemoglobin and hematocrit were detected at 24 hours after replacement (P＜ 0.05),and these were better in the experimental group than in the control group.No significant difference in D-Dimer was observed between the two groups after replacement (P＞ 0.05).Operation time and intraoperative dominant blood loss were significantly associated with hemoglobin and hematocrit at 24 hours after replacement (P＜0.05).The changes in hemoglobin and hematocrit at 72 hours and 7 days after replacement were not apparently correlated with intraoperative D-Dimer changes.Obvious thrombus was not seen by lower limb venous ultrasonography after replacement.These results indicated that the use of tranexamic acid before total knee arthroplasty apparently reduced the intraoperative dominant blood loss,shortened operation time,and noticeably decreased hidden blood loss at 1 day after replacement,which was caused by the increased fibrinolysis with surgical stress,and did not apparently impact other hidden blood loss induced by other mechanism.Simultaneously,tranexamic acid is safe and reliable,and does not increase the risk of perioperative thrombus.

The shoulder joint is the largest joint of range of motion in the human body,but the stability is relatively low.Ath-letes and soldiers who engage in the high strength training are prone to shoulder joint instability, while Bankart lesion is the common factor which leads to shoulder joint instability.With the invention of the new medical devices and updating therapeutic method, the treatment of Bankart lesions is improved continuously.In this paper, we will review the key points of diagnosis and therapeutic method.

Objective Bone cement joint prosthetic aseptic loosening always occurs in the bone cement-bone interface, while the mechanical strength of the interface mainly depends on the microstructure and adhesive strength.The aim of this study was to ex-plore the bone microstructure and the cement bone interfacial biomechanics of osteoarthritis(OA) and rheumatoid arthritis(RA), and also discuss the correlation. Methods Twenty trabecular bone specimens of tibial plateaus were taken from OA and RA patients who underwent total knee arthroplasty( TKA) .The microstructural parameters of the trabecular bone specimens were measured by Skyscan1176 microcomputed tomography.The bone specimens were made into cementbone models, which were tested by INSTRON strength tester.The association of bone microstructure and interfacial shear stress was analyzed subsequently. Results ①Bone volume fraction ( BV/TV) ( r=-0.313) , trabecular thickness ( Tb.Th) ( r=-0.340) ,trabecular spacing ( Tb.Sp) ( r=0.345) of OA had obvious correlation to shear strength (P<0.05).The cement-bone interfacial strength of medial tibial plateaus[(87.45±52.50)N] was lower than lateral tibial plat-eaus[(177.25±71.11)N] of OA (P<0.05).②Bone volume fraction (BV/TV)(r=0.343), trabecular number (Tb.N)(r=0.391) of RA had obvious correlation to shear strength (P<0.001).The cement-bone interfacial strength of lateral tibial plateaus[(62.23±46.22) N] was lower than medial tibial plateaus[(79.20±56.37N)] of RA (P<0.05).③The interfacial strength of OA[(132.35±76.64)N] was higher than RA[(71.05±51.55)N] (P<0.05). Conclusion There are differences of microstructure between OA and RA, which lead to the distinction of strength of cement -bone interface.And it has a certain guiding role of analyzing the biomechanics in TKA.

The rotator cuff injury may be associated with subacromial impingement , ischemic degeneration , abnormal biome-chanical factors, However, depending on the size and type of repair , acute or chronic injury , can need different repair methods .Under the influence of various factors , traditional repair methods have the lower success rate for rotator cuff injury .With deeply understanding the mechanism of injury and the development of tissue engineering and materials science , the treatment of rotator cuff injury may get the better results with the use of new materials .

Objective Recent studies show that the PI3K/Akt signaling pathway is a key regulatory signal in both bone for-mation and bone remodeling .The experiment aimed to investigate the effects of inhibiting the PI 3K/Akt signaling pathway on the prolif-eration and cell cycles of MC3T3-E1 cells. Methods We treated MC3T3 -E1 cells with PF-04691502 the inhibitor of the PI3K/Akt signaling pathway .Then we determined the proliferative activity of the cells by MTS assay , detected the cell cycles by flow cytometry , and measured the expression of cell cycle-related proteins by Western blot . Results After inhibition of the PI3K/Akt signaling path-way with PF-04691502 at 30, 150 and 750 nmol/L, the proliferation of MC3T3-E1 cells was reduced in a dose-dependent manner to 0.647 ±0.041, 0.423 ±0.011 and 0.159 ±0.004, respectively, as compared with 1 ±0.056 in the control group (P<0.01).Sim-ultaneously , the percentage of the cells in the sub-G1 phase was significantly higher in the 1 μmol/L group than in the control ([1.45 ±0.43]%vs [0.27 ±0.21]%, P<0.01) and the expression of cyclin D1 was decreased. Conclusion Inhibition of the PI3K/Akt signaling pathway can block MC 3T3-E1 cells in the sub-G1 phase and reduce the proliferation of the cells .

[Objective]To investigate the inhibitory effect of zoledronic acid(ZA) on osteolysis induced by human periprosthetic tissue in a novel animal model.[Method]Human periprosthetic tissue that was harvested from a patient receiving total hip revision was grafted on the calvaria bone of SCID beige mice. ZA was injected directly beneath the scalp of mice once,2 days post surgery. The mice were sacrificed 2 or 4 weeks after transplantation and the calvaria with grafted human tissue was collected for further detection.[Result]The grafted tissues were found survive for at least 4 weeks in the animals. Bone collagen collapse of the calvaria caused by periprosthetic tissue was demonstrated by HE staining. Significantly higher level of TNF-?,IL-6,RANKL and CPK both in gene expression and protein release were detected in PT grafted group,as compared with the control. Once administration of ZA remarkably reduced the expression of RANKL and CPK in both gene and protein level without affecting TNF-? and IL-6.[Conclusion]Once and local injection of ZA effectively inhibits the osteolysis induced by human periprosthetic tissue with a long lasting effect. The novel animal model could serve for evaluating the pharmaceutical effect on periprosthetic osteolysis.

Objective Clinically, the anterior cruciate ligament ( ACL) can be reconstructed by either ligament advanced reinforcement system ( LARS) artificial ligament or hamstring tendon autograft ( HTAG) . This study aims to compare the early clinical outcomes of LARS versus HTAG in the treatment of ACL. Methods This study included 38 cases of ACL injury treated in our de-partment from March 2012 to August 2014, 18 by LARS artificial ligament and the other 20 by HTAG. Before and at 18 months after surgery, we evaluated the clinical outcomes of the tow strategies using the Lysholm knee scoring scale and International Knee Documen-tation Committee ( IKDC) scoring systems, and conducted statistical analysis on the follow-up findings. Results Statistically signifi-cant differences were not observed preoperatively between the LARS and HTAG groups either in the Lyshrolm scores (46.78±1.52 vs 46.80 ±1.89, P>0.05) or in the IKDC scores (42.83±1.47 vs 42.20±1.61, P>0.05), nor at 18 months postoperatively in the Lyshrolm scores (93.52±3.19 vs 94.10±1.37, P>0.05) or the IKDC scores (92.11± 1.45 vs 93.15±1.76, P>0.05). However, both the LARS and HTAG groups showed significant differences in the Lyshrolm and IKDC scores at the baseline as compared with those at 18 months after oper-ation ( P<0.05) . Conclusion Both LARS artificial ligament ham-string tendon autograft can achieve good early clinical outcomes in ACL reconstruction.

BACKGROUND:Hidden blood loss, a frequent occurrence fol owing artificial joint replacement, greatly affects the recovery from total hip arthroplasty. Many factors have been shown to have a correlation with the hidden blood loss, but the specific mechanism is not yet clear.
OBJECTIVE:To investigate the correlation of patients’ baseline (sex, age, underlying disease, obesity), prosthesis types, surgical time with hidden blood loss fol owing total hip arthroplasty, as wel as the association between hidden blood loss and prognosis.
METHODS:Ninety patients undergoing total hip arthroplasty were enrol ed in this study. Using Gross formula, we calculated the total blood loss according to height, weight, and pre-and post-operative hematocrit, and subtracted the dominant loss of blood to get the quantitative value of hidden blood loss. According to the criterion, the 90 patients were divided to two groups:group I:volume of hidden blood loss>480 mL, group II:volume of hidden blood loss<480 mL. Then we analyze the difference in the gender, age, underlying disease, type of prosthesis, surgical time between the two groups, and whether there was a correlation between these factors and hidden blood loss. Al the patients were fol owed for 1 year. Perioperative complications and survival curves were observed and monitored in the two groups.
RESULTS AND CONCLUSION:There were 39 patients in the group I, including 64.1%males, 64.1%hypertension patients, 35.9%diabetic patients, 7.7%patients receiving cement prosthesis;while, there were 51 patients in the group II, including 37.3%males, 25.5%hypertension patients, 5.9%diabetic patients, 35.3%patients receiving cemented prosthesis, showing a significant difference between the two groups. Based on these experimental findings, age, hypertension, diabetes mel itus, type of prosthesis were shown to be factors independently associated with hidden blood loss;however, obesity and smoking exhibited no correlation with hidden blood loss. In addition, a statistical difference in the survival rate was found at admission and during the 1-year fol ow-up.