Influencing factors of preoperative pulmonary function in elderly patients undergoing rotator cuff surgery / 北京大学学报(医学版)

OBJECTIVE@#To analyze the preoperative pulmonary function in rotator cuff injury patients and the possible influencing factors.@*METHODS@#All the rotator cuff surgery patients who underwent pre-operative pulmonary function examination in Peking University Third Hospital from Jan. 2020 to Jun. 2020 were retrospectively reviewed. Their perioperative medical records and main parameters of pulmonary function were collected from database management system, and their gender, age, body mass index (BMI), smoking history, time from injury, visual analogue scale (VAS) and other factors impacting on preoperative pulmonary function were studied.@*RESULTS@#Twenty-nine patients with rotator cuff injury were included, among whom 1 patient was reported to have restrictive ventilation dysfunction and 2 patients to have obstructive ventilation dysfunction. All the three patients denied the history of respiratory diseases, and had no respiratory symptoms. In all enrolled patients, the mean forced expiratory volume in one second (FEV1)/ forced vital capacity (FVC) was 79.2%±5.9%, and the mean VAS pain score was 3.66±1.26. In addition, the dynamic pulmonary functions (FVC, FEV1) were reduced in more than half of the elderly, and the total lung capacity (TLC) was lower than the estimated value in 2/3 of the elderly. There were significant differences in three main indexes of pulmonary functions between genders, and the percentage of the estimated TLC between normal BMI group (18 kg/m2 < BMI < 24 kg/m2) and overweight/obesity group (BMI≥24 kg/m2) was significantly different. Based on the injury time longer than 1 year or not, the results indicated that FVC and TLC were significantly different between the two groups.@*CONCLUSION@#In addition to gender and age, time from injury and severity of pain, as well as overweight/obesity, may influence pulmonary function outcomes in the elderly rotator cuff patients. Targeted intervention can be carried out on these factors before surgery. Preoperative lung function test can be used as one of the basic evaluation indexes for respiratory training and rehabilitation of patients.

Finite element analysis of the graft stresses after anterior cruciate ligament reconstruction / 北京大学学报(医学版)

OBJECTIVE@#To explore the stress distribution characteristics of the graft after anterior cruciate ligament (ACL) reconstruction, so as to provide theoretical reference for the surgical plan of ACL reconstruction.@*METHODS@#Based on 3D MRI and CT images, finite element models of the uninjured knee joint and knee joint after ACL reconstruction were established in this study. The uninjured knee model included femur, tibia, fibula, medial collateral ligament, lateral collateral ligament, ACL and posterior cruciate ligament. The ACL reconstruction knee model included femur, tibia, fibula, medial collateral ligament, lateral collateral ligament, ACL graft and posterior cruciate ligament. Linear elastic material properties were used for both the uninjured and ACL reconstruction models. The elastic modulus of bone tissue was set as 17 GPa and Poisson' s ratio was 0.36. The material properties of ligament tissue and graft were set as elastic modulus 390 MPa and Poisson's ratio 0.4. The femur was fixed as the boundary condition, and the tibia anterior tension of 134 N was applied as the loading condition. The stress states of the ACL of the intact joint and the ACL graft after reconstruction were solved and analyzed, including tension, pressure, shear force and von Mises stress.@*RESULTS@#The maximum compressive stress (6.34 MPa), von Mises stress (5.9 MPa) and shear stress (1.83 MPa) of the reconstructed ACL graft were all at the anterior femoral end. It was consistent with the position of maximum compressive stress (8.77 MPa), von Mises stress (8.88 MPa) and shear stress (3.44 MPa) in the ACL of the intact knee joint. The maximum tensile stress of the graft also appeared at the femoral end, but at the posterior side, which was consistent with the position of the maximum tensile stress of ACL of the uninjured knee joint. More-over, the maximum tensile stress of the graft was only 0.88 MPa, which was less than 2.56 MPa of ACL of the uninjured knee joint.@*CONCLUSION@#The maximum compressive stress, von Mises stress and shear stress of the ACL graft are located in the anterior femoral end, and the maximum tensile stress is located in the posterior femoral end, which is consistent with the position of the maximum tensile stress of the ACL of the uninjured knee joint. The anterior part of ACL and the graft bore higher stresses than the posterior part, which is consistent with the biomechanical characteristics of ACL.

Clinical characteristics of 4355 patients with anterior cruciate ligament injury / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>Clinical features of anterior cruciate ligament (ACL) injury are important for its prevention, diagnosis and treatment. However, few studies have reported such data, especially in China. The purpose of this study was to describe the clinical characteristics of ACL injury on a large cohort.</p><p><b>METHODS</b>Between 1993 and 2007, a total of 4355 ACL deficient inpatients (612 athletes and 3743 non-athletes) were registered. Data were collected using a special database system. And the distributions of characteristics in different groups were compared and analyzed statistically.</p><p><b>RESULTS</b>All subjects were confirmed with ACL tear during surgery. Statistical analysis revealed that the percentage of females in Athlete Group was significantly higher than that in Non-athlete Group (56.05% vs. 24.95%, P < 0.001). This study also found that sports trauma was the main cause of ACL tears. Soccer, basketball, judo, wrestling and track and field were the five most responsible activities for athletes. The average injury time for athletes was significantly shorter than that for non-athletes (413.3 days vs. 717.5 days, P < 0.001). Three thousand nine hundred and eight cases were ordered ACL reconstruction (76.04% single-bundle, 18.30% double-bundle). Three hundred and forty-five patients (7.92%) were combined with other ligaments injuries, 2667 (61.24%) were found with various grades of cartilage lesions, and 3377 (77.54%) were found with meniscal injury.</p><p><b>CONCLUSIONS</b>Sports trauma was the main cause of ACL tears in China, and reconstruction had become the principal surgical choice. In order to restore knee joint stability and reduce the incidence of cartilage and meniscal injury, patienttailored ACL reconstruction should be suggested at the right moment.</p>

Changes of histology and capsular collagen in a rat shoulder immobilization model / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>Shoulder immobilization can induce adhesion of the joint, capsular contracture or lead to the condition of frozen shoulder. However, little is known about the histological effects of immobilization on the shoulder joint. This study aimed to explore the effect of immobility on the subscapular bursa (SSB) and the joint capsular content, including the distribution of types I and III collagen, within an immobilized rat shoulder.</p><p><b>METHODS</b>Forty-six Sprague-Dawley rats were randomly divided into one control group (n = 6) and four immobilization groups (n = 10 in each group), in which the left shoulders were immobilized with plaster for 1, 2, 3 and 4 weeks. At the end of each time point, 2 rats from each group were euthanized and shoulders prepared for serial histological observations of the glenohumeral joints, as well as picrosirius red and immunohistochemical observation of type III collagen. Histological sections of the remaining rat shoulders were used for the immunohistochemical detection of the capsular content of types I and III collagen.</p><p><b>RESULTS</b>The hyperplastic synovium of the anterior capsule obstructed the communication between the SSB and the glenohumeral joint cavity at 2 and 3 weeks. The adhesion of the SSB appeared at 3 and 4 weeks. The quantitative and qualitative results showed that the capsular contents of types I and III collagen progressively increased at 2, 3 and 4 weeks, and that type III collagen was distributed extensively within the joint capsule at 2 and 3 weeks.</p><p><b>CONCLUSION</b>Immobilization of the rat shoulder induced synovial hyperplasia of the joint capsule, adhesion of the SSB and an increase of the capsular content of types I and III collagen.</p>

In vitro damage to hairs by Trichophyton mentagrophytes and Microsporum canis / 中华皮肤科杂志

Objective To observe the in vitro damage to hairs by Trichophyton mentagrophytes and Microsporum canis using light microscopy and scanning electron microscopy ( SEM ), and to compare the differences in the duration needed for the two fungi to damage hairs in different age groups. Methods We collected healthy hairs from different age groups, and performed hair perforation test in vitro. The damage to the hairs was observed by SEM and light microscopy. Results Both T. mentagrophytes and M. canis could damage the hairs. The duration needed for T. mentagrophytes to damage the hairs was significantly shorter than that for M. canis in all age groups ( P