BACKGROUND:Intermittent negative pressure has been proven to promote the repairing of soft tissue and bone healing, but the effect of negative pressure on the tendon-bone healing after anterior cruciate ligament reconstruction has not been reported.
OBJECTIVE:To research the effect of intermittent negative pressure on tendon-bone healing after anterior cruciate ligament reconstruction and on the biomechanics of tendon grafts.
METHODS:A total of 24 New Zealand white rabbits were randomly selected to establish the models of anterior cruciate ligament reconstruction of autogenous semitendinosus. The hind leg of one side was selected randomly as the negative pressure group, and the joint of the negative pressure side was connected with the micro-negative pressure aspirator through drainage tube and maintained a low-intensity and intermittent negative pressure;the contralateral hind leg was as the control and connected with ordinary drainage tube. Drainage tubes of both sides were removed at the same time after 5 days. At 6 weeks after modeling, the joint fluid was drawn to detect the expression levels of interleukin-1β;femur-ligament-tibia complex was used for tension measurement of tendon graft, and histological observation of tendon-bone interface.
RESULTS AND CONCLUSION:One rabbit had joint infection, and final y 23 rabbits were included in the study. Tension measurement results showed that maximum load for breakage in negative group pressure was significantly greater than that in the control group (P<0.05). Histological observation found that the number of osteoblasts in the negative pressure group was significantly more than that in the control group, and the difference was statistical y significant (P<0.01). Detection of synovial fluid showed that iterleukin-1βcontent in synovial fluid of the negative pressure group was lower than that in the control group, and the difference was statistical y significant (P<0.01). Intermittent negative pressure may play an active role in tendon-bone healing and modeling of tendon graft after anterior cruciate ligament reconstruction.

Aim To study the therapeutic effect of helicid on osteoarthritis (OA) of joint instability model, and explore the mechanism of helicid in the treatment of OA. Methods A rat knee model of OA was established by the medial meniscectomy (MMx) method. After treatment with helicid, HE and safranin O/fast green staining methods were used to observe the his-topathological changes of rat knee articular cartilage; Western blot was used to detect the protein expression level of Trpvl in rat synovial tissue. Immunohistochemical staining was used to examine the expression of Trpvl in rat knee articular cartilage and synovial tissues. Results Helicid significantly slowed down the degeneration of rat knee articular cartilage as shown by HE and safranin O/fast green staining. Western blot results showed that helicid down-regulated the expression of Trpvl in rat synovial tissue examined. Immunohistochemical results showed that helicid significantly reduced the expression of Trpvl in both of knee articular cartilage and synovial tissues. Conclusions Helicid prominently decreases MMx-induced articular cartilage damage and cartilage matrix loss, thereby exerting a therapeutic effect on OA.

【Objective】 To establish a digital model of lumbar 4 and lumbar 5 vertebral bodies through three-dimensional imaging technology so as to explore the precise placement of pedicle screws during the lumbar posterior internal fixation operation. 【Methods】 CT scan image data set of lumbar spine included six specimens. Then lumbar modeling was produced using Mimics software， implanting pedicle screws was simulated with the computer to determine the reliability of pedicle screw for herringbone crest method， Weinstein method， and Magerl method. 【Results】 This study included six specimens （4 males and 2 females）， with an average age of 42.83 years. The distance from the right Magerl entry point to the actual entry point of the lumbar 4 vertebrae was significantly greater than that of the left side. The distance from the left herringbone crest entry point of lumbar 4 vertebrae to the actual entry point was significantly greater than Weinstein method and Magerl method （P<0.001 and P<0.001）， and the distance from the right herringbone crest entry point of lumbar 4 vertebrae to the actual entry point was significantly greater than Weinstein method （P=0.003）. Both left and right abduction angles of lumbar 4 vertebrae were true abduction angle >Magerl abduction angle > Weinstein abduction angle > herringbone abduction angle. The distances of true-Weinstein and true-herringbone ridges on the left side of lumbar 5 vertebrae were significantly greater than those on the right side （P=0.002 and P=0.004）， and the Weinstein abduction angle on the right side of lumbar 5 vertebrae was greater than that on the left side （P=0.003）. For the left and right sides of lumbar 5 vertebrae， the distance from herringbone crest entry point to the actual entry point was significantly greater than that of Weinstein method and Magerl method （P<0.001 and P<0.001）， and the distance from the Magerl entry point to the real entry point was significantly greater than that of the Weinstein method. The abduction angle of left and right sides of lumbar 5 vertebrae was as follows： true abduction angle > Magerl abduction angle > Weinstein abduction angle > herringbone abduction angle. 【Conclusion】 Both Weinstein entry point and Magerl entry point for lumbar 4 and lumbar 5 vertebra are close to the real entry point. The Weinstein abduction angle and Magerl abduction angle of lumbar 4 and lumbar 5 vertebrae have minor differences compared with real abduction angle. Therefore， it is recommended that Weinstein method is the preferred choice for lumbar 4 pedicle screw placement， while Weinstein method or Magerl method is the preferred choice for lumbar 5 pedicle screw placement.

【Objective】 Until now, most clinical and basic studies on Kashin-Beck disease (KBD) have focused on the visible deformed extremities, and there is a lack of reports concerning their spinal features, especially for the atlantoaxial joint. The purpose of this study was to determine the prevalence and radiographic features of atlantoaxial dislocation (AAD) in KBD in adult patients. 【Methods】 The prevalence and radiographic features of AAD were determined by the basic information collected, clinical symptoms, and lateral and dynamic plain radiography in 111 KBD patient and 120 non-KBD participants. In the KBD group, AAD and non-AAD patients were compared in age, gender, height, weight, BMI, smoking history, chronic history, disease duration and grade of disease so as to identify the related factors of the occurrence of AAD. 【Results】 Symptoms at the neck or neurological manifestations were present in 17.5% (21/120) in the non-KBD population and 39.6% (44/111) patients with KBD. AAD case was not detected in the non-KBD population, while in 16.2% (18/111) of KBD patients in the endemic area. The prevalence was higher in the KBD patients than in the non-KBD population, and there was a significant difference in the detection rate of AAD between the two groups (χ²=21.10, P<0.001). Plain radiography demonstrated that there were 10 (55.6%) cases with separation of the odontoid process and the other 8 (44.4%) cases with hypoplasia of odontoid process. Anterior AAD was noted in 12 (66.7%) patients and posterior AAD in 6 (33.3%) cases based on the displacement direction, while 16 (88.9%) cases were reducible and 2 (11.1%) cases were irreducible on the basis of the reducibility. Comparing the 93 patients with non-AAD KBD patients and 18 patients with AAD patients, there was no significant difference in age, sex, BMI, history of medical disease or smoking (all P>0.05). There were significant differences in height, weight, disease duration and grade of disease between AAD and non-AAD patients (all P<0.05). 【Conclusion】 KBD can cause the occurrence of atlantoaxial dislocation by inducing separation or hypoplasia of the odontoid process. This research may provide clinical evidence for screening, earlier prevention and treatment of atlantoaxial dislocation in adult KBD patients.