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Hu sheep, an indigenous breed in China known for its high fecundity, are being studied to improve their growth and carcass traits. MSTN is a negative regulator of muscle development, and its inactivation results in muscularity. The C-CRISPR system, utilizing multiple neighboring sgRNAs targeting a key exon, has been successfully used to generate genes for complete knockout (KO) monkeys and mice in one step. In this study, the C-CRISPR system was used to generate MSTN-edited Hu sheep; 70 embryos injected with Cas9 mRNA and four sgRNAs targeting exon 3 of sheep MSTN were transferred to 13 recipients. Out of 10 lambs born from five recipients after full-term pregnancies, nine had complete MSTN KO with various mutations. No off-target effects were found. These MSTN-KO Hu sheep showed a double-muscled (DM) phenotype, characterized by a higher body weight at 3 and 4 months old, prominent muscular protrusion, clearly visible intermuscular groves, and muscle hypertrophy. The molecular analysis indicated enhanced AKT and suppressed ERK1/2 signaling in the gluteus muscle of the edited Hu sheep. In conclusion, MSTN complete KO Hu sheep with a DM phenotype were efficiently and specifically generated using C-CRISPR, and the C-CRISPR method is a promising tool for farm animal breeding. [ABSTRACT FROM AUTHOR]

BACKGROUND: Patellofemoral pain syndrome is a common disease in the field of sports injuries. Research in and outside China is increasing year by year, but there is no visual analysis for patellofemoral pain syndrome. OBJECTIVE: To objectively analyze the literature research on patellofemoral pain syndrome in and outside China in the past 13 years, to summarize the recent research directions in this field and to sort out the knowledge structure in and outside China. METHODS: Relevant articles on patellofemoral pain syndrome were collected from Web of Science and CNKI. Citespace software was used for visual analysis to show the research hotspots and development trends of this field. RESULTS AND CONCLUSION: (1) A total of 1 679 articles were finally included in the Web of Science database. The authors with the most articles are De Oliveira Silva D from La Trobe University in Melbourne, Australia and Crossley KM from the University of Melbourne, Australia. Hot keywords are hip, biomechanics, prevention (prognosis), prevalence disease rate, consensus statement, gender differences, electromyographic activity, risk factor, and osteoarthritis. (2) A total of 214 articles were included and analyzed in the CNKI database. The author with the most articles is Miao Ping from the Rehabilitation Department of the Second Affiliated Hospital of Guangzhou Medical University. Hot keywords are arthroscopy, biomechanics, strength training, lateral femoral muscle, surface electromyography, patellofemoral arthritis, and joint replacement. (3) International research hotspots show the biomechanical characteristics of increased knee external rotation, increased hip adduction, and decreased hip internal rotation during patient exercise. Strengthening the hip abductors and external rotators can effectively improve the pain and function of patients. At present, the most appropriate method to treat the disease in the world is a customized multi-modal intervention program, including strengthening of the gluteal muscles and quadriceps, emphasizing education and activity adjustment. (4) The results of major Chinese studies in this field confirm that the use of arthroscopic surgery can improve the pain of patients with patellofemoral pain syndrome, and patellofemoral joint replacement has a certain effect on early severe patellofemoral arthritis in such patients. Rehabilitation training methods are mainly based on hip joint strength training, supplemented by core muscles, lower limb eccentric strength and neuromuscular control training. Compared with foreign countries, the unique research hotspots in China are acupuncture and Chinese medicine. [ABSTRACT FROM AUTHOR]

The hip joint is the largest weight‐bearing joint in the body and is surrounded by dense capsules and thick muscles. Hip arthroscopic techniques are suitable for the treatment of hip‐related conditions. These minimally invasive techniques have rapidly developed in China since 2007. Moreover, they have been used in the treatment of gluteal muscle contracture, snapping hip syndrome, femoral acetabular impingement, acetabular labral injury, hip labral calcification, synovial chondroma, osteoid osteoma, synovitis, osteonecrosis of the femoral head, and developmental dysplasia of the hip. This technique has showed its advantage in the total debridement of lesions, precision treatment, and less trauma. However, we lack understanding of the overall development of arthroscopic techniques in China. This review illustrates the recent development of hip arthroscopic techniques in China and related research progress. [ABSTRACT FROM AUTHOR]

Background: Muscle weakness is a key factor in the increase risk of falls and might also play a significant role in the increase of risk of hip fracture. Computed tomography‐measured muscle size and muscle density are well‐established imaging biomarkers used in studies of physical function, frailty or cancer, but limited to hip fracture. In particular, it is warranted to have a better understanding of the performance of muscle size and density in the discrimination of acute hip fractures. We also aim to determine age‐related differences of muscle size and density in healthy controls and hip fracture patients. Methods: Four hundred thirty‐eight low‐energy acute hip fracture cases and 316 healthy controls from the China Action on Spine and Hip Status study were included in the study. Muscle cross‐sectional area and density were measured for the gluteus maximus and gluteus medius and minimus. Areal bone mineral density (aBMD) of the femoral neck and total hip was measured. Using propensity score matching, we generated three samples with cases and controls matched for age, body mass index, and gender: femoral neck fracture (FNF), intertrochanteric fracture (ITF), and any hip fracture vs. controls, respectively. Results: Handgrip strength, gluteus muscle area and density, and bone parameters of the matched hip fracture groups were lower than those of the correspondence control groups, respectively (P < 0.05). The univariate analysis showed that associations of aBMD with FNF and with ITF were significantly weaker than associations between fracture and muscle parameters. Gluteus medius and minimus muscle density showed the highest areas under the curve (AUC) with FNF (0.88, 95% confidence interval, 0.85–0.92) and trochanteric fracture (0.95, 95% confidence interval, 0.92–0.97). The model including all muscle and bone parameters provided the highest AUC (FNF: AUC 0.912; ITF: AUC 0.958), and AUC results of another selected model without muscle density showed that association with fracture significantly dropped (FNF: AUC 0.755; ITF: AUC 0.858). Separate results for the two age groups younger and older than 70 years showed no age‐related significant differences in discriminate models. Conclusions: Muscle density performs better than aBMD from hip computed tomography X‐ray absorptiometry and muscle size in discrimination of hip fracture. Combination of aBMD and muscle density provided the best discrimination. The integration of muscle assessments may trigger a paradigm shift in hip fracture prediction. Gluteus muscle density should also be evaluated as treatment outcome. [ABSTRACT FROM AUTHOR]

Background: Gluteal muscle contracture (GMC) is a clinical syndrome characterized by the contracture of gluteal muscles, iliotibial band (ITB), and related fascia. GMC is much more prevalent in China, which has been proven to be associated with repeated intramuscular injections into the buttocks and the subsequent fibrosis and contracture.Generally, GMC is manifested mild. Here, we reported a severe case with arthrokatadysis.Case Presentations: A 25-year old man received multiple intramuscular injections of penicillin in the buttock when he was diagnosed with acute tonsillitis at 6 years old. Since then, he was injected penicillin regularly in local hospital because of the repeated acute tonsillitis until he was in high school. When the patient was found by the physical education teacher to be running in a state of external rotation of both feet, he was suggested to go to the hospital for treatment and was initially diagnosed to have GMC. He complained of occasional pain and limited range of motion in the hip joints. X-ray showed a typical arthrokatadysis. After arthroscopic release of GMC, the patient recovered well.Conclusions: This is possibly the first reported case of arthrokatadysis that was caused by GMC after repeated intramuscular injections into the buttocks. Although the patient recovered well by arthroscopic surgical release of bilateral gluteus maximus contractures, GMC should be paid more attention and treated as early as possible. [ABSTRACT FROM AUTHOR]

Summary: Background: We investigated an outbreak of gluteal abscesses following intramuscular (IM) injections given at a clinic in rural China to identify the causative agent, source, and method of exposure. Methods: We defined a case as an abscess that appeared at the site of an injection given since June 1, 2006. We compared case rates by injection route, medication, and diluents. We reviewed injection practices, and cultured abscesses and environmental sites for mycobacteria. Results: From October through December 2006, 5.8% (n =35) of 604 persons who had received injections at the clinic developed a case. All 35 cases occurred in 184 patients (attack rate=19.0%) who had received IM injections with various drugs that had been mixed with normal saline (NS); risk ratio=∞; p <0.0001. No cases occurred in the absence of NS exposure. We identified Mycobacterium abscessus from eight abscesses and from the clinic water supply, and observed the inappropriate reuse of a 16-gauge needle left in the rubber septum of 100ml multiple-dose bottles of NS in the clinic. Fourteen percent (n =527) of the 3887 registered residents of this village had been treated with IM drugs over a three-month period, often for minor illnesses. Conclusions: This outbreak of M. abscessus occurred from exposure to extrinsically contaminated NS through improper injection practices. Frequent treatment of minor illnesses with IM injections of antibiotics was likely an important contributing factor to the size of this outbreak. [Copyright &y& Elsevier]