SciCombinator

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Concept: Ligament

171

Spinal ligaments, such as the ligamentum flavum (LF), are prone to degeneration and iatrogenic injury that can lead to back pain and nerve dysfunction. Repair and regeneration strategies for these tissues are lacking, perhaps due to limited understanding of spinal ligament formation, the elaboration of its elastic fibers, maturation and homeostasis. Using immunohistochemistry and histology, we investigated murine LF elastogenesis and tissue formation from embryonic to mature postnatal stages. We characterized the spatiotemporal distribution of the key elastogenic proteins tropoelastin, fibrillin-1, fibulin-4 and lysyl oxidase. We found that elastogenesis begins in utero with the microfibril constituent fibrillin-1 staining intensely just before birth. Elastic fibers were first detected histologically at postnatal day (P) 7, the earliest stage at which tropoelastin and fibulin-4 stained intensely. From P7 to P28, elastic fibers grew in diameter and became straighter along the axis. The growth of elastic fibers coincided with intense staining of tropoelastin and fibulin-4 staining, possibly supporting a chaperone role for fibulin-4. These expression patterns correlated with reported skeletal and behavioral changes during murine development. This immunohistochemical characterization of elastogenesis of the LF will be useful for future studies investigating mechanisms for elastogenesis and developing new strategies for treatment or regeneration of spinal ligaments and other highly elastic tissues.

Concepts: Liver, Anatomical pathology, Histology, Osteoarthritis, Immunohistochemistry, Staining, Ligament, Microtome

169

The effects of hip muscle strength and activation on anterior cruciate ligament injury biomechanics, particularly knee valgus loading, have been reported in isolation and with equivocal results. However, the combination of these factors influences joint biomechanics. This investigation evaluated the influence of hip strength on gluteal activation and knee valgus motion. Maximal isometric hip abduction (ABD) and external rotation (ER) contractions were used to define High and Low strength groups. Knee kinematics and gluteus maximus (GMax) and medius (GMed) EMG amplitudes obtained during landing were compared between High and Low strength groups after controlling for the potential confounding influence of sex. Knee valgus motion did not differ between the High and Low hip ABD and ER strength groups. However, the Low ABD and ER strength groups displayed greater GMed and GMax EMG amplitudes, respectively, compared to the High strength groups. These findings suggest that weaker individuals compensate for a lack of force production via heightened neural drive. As such, hip muscle strength influences knee valgus motion indirectly by determining neural drive requirements.

Concepts: Knee, Anterior cruciate ligament, Electromyography, Muscular system, Ligament, Anterior cruciate ligament injury, Cruciate ligament, Gluteal muscles

169

PurposeIn this retrospective study we investigated the clinical and radiological outcome after operative treatment of acute Rockwood III-V injuries of the AC-joint using two acromioclavicular (AC) cerclages and one coracoclavicular (CC) cerclage with resorbable sutures. METHODS: Between 2007 and 2009 a total of 39 patients fit the inclusion criteria after operative treatment of acute AC joint dislocation. All patients underwent open reduction and anatomic reconstruction of the AC and CC-ligaments using PDS® sutures (Polydioxane, Ethicon, Norderstedt, Germany). Thirty-three patients could be investigated at a mean follow up of 32+/-9 months (range 24–56 months). RESULTS: The mean Constant score was 94.3+/-7.1 (range 73–100) with an age and gender correlated score of 104.2%+/-6.9 (88-123%). The DASH score (mean 3.46+/-6.6 points), the ASES score (94.6+/-9.7points) and the Visual Analogue Scale (mean 0.5+/-0,6) revealed a good to excellent clinical outcome. The difference in the coracoclavicular distance compared to the contralateral side was <5 mm for 28 patients, between 5-10 mm for 4 patients, and more than 10 mm for another patient. In the axial view, the anterior border of the clavicle was within 1 cm (ventral-dorsal direction) of the anterior rim of the acromion in 28 patients (85%). Re-dislocations occured in three patients (9%). CONCLUSION: Open AC joint reconstruction using AC and CC PDS cerclages provides good to excellent clinical results in the majority of cases. However, radiographically, the CC distance increased significantly at final follow up, but neither the amount of re-dislocation nor calcifications of the CC ligaments or osteoarthritis of the AC joint had significant influence on the outcome.Level of evidenceCase series, Level IV.

Concepts: Osteoarthritis, Joint, Joints, Ligament, Joint dislocation, Clavicle, Acromioclavicular joint, Acromion

161

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.

Concepts: Knee, Anterior cruciate ligament, Cultural studies, Ligament, Anterior cruciate ligament injury, Anterior cruciate ligament reconstruction, Cruciate ligament, Ligaments

146

Autologous adipose stromal vascular fractions (SVFs) containing adipose tissue-derived stem cells (ASCs) are currently being used in clinical settings for various orthopedic applications for human patients. Due to its potential capability of regenerating cartilage, bone, and tendons, autologous adipose SVFs are being tried in treating patients with osteoarthritis (OA), chondromalacia, meniscus tear, osteonecrosis of the femoral head, and tendon injuries. Here, we have reviewed available human clinical studies with regard to patient applications of autologous adipose SVF containing ASCs, specifically assessing effectiveness and safety in the field of orthopedic disorders. All studies reviewed in this article presents potential benefits of autologous adipose SVF in various orthopedic applications without any serious side effects.

Concepts: Bone, Clinical trial, Collagen, Extracellular matrix, Effectiveness, Cartilage, Ligament, Tendon

110

68

The health of cloned animals generated by somatic-cell nuclear transfer (SCNT) has been of concern since its inception; however, there are no detailed assessments of late-onset, non-communicable diseases. Here we report that SCNT has no obvious detrimental long-term health effects in a cohort of 13 cloned sheep. We perform musculoskeletal assessments, metabolic tests and blood pressure measurements in 13 aged (7-9 years old) cloned sheep, including four derived from the cell line that gave rise to Dolly. We also perform radiological examinations of all main joints, including the knees, the joint most affected by osteoarthritis in Dolly, and compare all health parameters to groups of 5-and 6-year-old sheep, and published reference ranges. Despite their advanced age, these clones are euglycaemic, insulin sensitive and normotensive. Importantly, we observe no clinical signs of degenerative joint disease apart from mild, or in one case moderate, osteoarthritis in some animals. Our study is the first to assess the long-term health outcomes of SCNT in large animals.

Concepts: Death, Osteoarthritis, Gerontology, Knee, Joint, Ageing, Cloning, Ligament

35

The primary objective was to calculate the rate of return to sport (RTS) following anterior cruciate ligament (ACL) reconstruction in elite athletes. Secondary objectives were to estimate the time taken to RTS, calculate rates of ACL graft rupture, evaluate postsurgical athletic performance and identify determinants of RTS.

Concepts: Rates, Knee, Anterior cruciate ligament, Ligament, Anterior cruciate ligament reconstruction, Cruciate ligament, Ligaments, Rate of return

35

The Royal Dutch Society for Physical Therapy (KNGF) instructed a multidisciplinary group of Dutch anterior cruciate ligament (ACL) experts to develop an evidence statement for rehabilitation after ACL reconstruction.

Concepts: Evidence-based medicine, Knee, Anterior cruciate ligament, Ligament, Anterior cruciate ligament injury, Anterior cruciate ligament reconstruction, Cruciate ligament, Hamstring

33

Regular exercise protects against degenerative joint disorders, yet the mechanisms that underlie these benefits are poorly understood. Chronic, low-grade inflammation is widely implicated in the onset and progression of degenerative joint disease.

Concepts: Bone, Infection, Rheumatoid arthritis, Cartilage, Osteoarthritis, Knee, Joint, Ligament