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Sample records for tendon tears comparison

  1. Proximal Biceps Tendon and Rotator Cuff Tears.

    PubMed

    Virk, Mandeep S; Cole, Brian J

    2016-01-01

    The long head of biceps tendon (LHBT) is frequently involved in rotator cuff tears and can cause anterior shoulder pain. Tendon hypertrophy, hourglass contracture, delamination, tears, and tendon instability in the bicipital groove are common macroscopic pathologic findings affecting the LHBT in the presence of rotator cuff tears. Failure to address LHBT disorders in the setting of rotator cuff tear can result in persistent shoulder pain and poor satisfaction after rotator cuff repair. Tenotomy or tenodesis of the LHBT are effective options for relieving pain arising from the LHBT in the setting of reparable and selected irreparable rotator cuff tears. PMID:26614474

  2. Supraspinatus Intramuscular Calcified Hematoma or Necrosis Associated with Tendon Tear

    PubMed Central

    Lädermann, Alexandre; Genevay, Muriel; Abrassart, Sophie; Schwitzguébel, Adrien Jean-Pierre

    2015-01-01

    Introduction. Rotator cuff intramuscular calcification is a rare condition usually caused by heterotopic ossification and myositis ossificans. Case Presentation. We describe a patient with voluminous calcified mass entrapped in supraspinatus muscle associated with corresponding tendon tear. Histological examination corresponded to a calcified hematoma or necrosis. Patient was surgically managed with open excision of the calcified hematoma and rotator cuff arthroscopic repair. At 6 months, supraspinatus muscle was healed, and functional outcome was good. Discussion and Conclusion. We hypothesized that supraspinatus intramuscular calcified hematoma was responsible for mechanical stress on the tendon. This association has never been described. PMID:26380138

  3. US appearance of partial-thickness supraspinatus tendon tears: Application of the string theory. Pictorial essay

    PubMed Central

    Guerini, H.; Fermand, M.; Godefroy, D.; Feydy, A.; Chevrot, A.; Morvan, G.; Gault, N.; Drapé, J.L.

    2012-01-01

    The supraspinatus tendon is composed of 5 different layers consisting of intertwining bundles. On a front portion of the tendon, the layers become coated bundles which insert on the trochanter. At the insertion, the superficial or bursal surface of the tendon corresponding to the tendon fibers in contact with the subacromial bursa can be distinguished from the deep surface corresponding to the fibers in contact with the glenohumeral joint. A tendon tear may involve partial or total disruption of the tendon fibers and is called full-thickness tear if it affects the entire tendon, and partial-thickness tear if it involves only part of the tendon. Partial-thickness tears of the supraspinatus tendon include lesions of the superficial, deep and central surface or tendon delamination. A contrast enhanced examination requires injection of contrast agent into the joint (arthrography followed by computed tomography (CT) or magnetic resonance imaging (MRI)) to study the deep surface, and injection into the subacromial bursa (bursography followed by CT) to study the superficial surface. MRI and ultrasound (US) examination allow the study of these different tendon layers without the use of contrast agent (which is not possible at CT). PMID:23396264

  4. Identification of Suitable Reference Genes for Gene Expression Studies in Tendons from Patients with Rotator Cuff Tear

    PubMed Central

    Leal, Mariana Ferreira; Belangero, Paulo Santoro; Figueiredo, Eduardo Antônio; Cohen, Carina; Loyola, Leonor Casilla; Andreoli, Carlos Vicente; Smith, Marília Cardoso; de Castro Pochini, Alberto; Ejnisman, Benno; Cohen, Moises

    2015-01-01

    Rotator cuff tear is one of the most common causes of shoulder dysfunction. Gene expression analysis may be a useful tool for understanding tendon tears and the failure of cuff healing, and reverse-transcription quantitative polymerase chain reaction (RT-qPCR) has become an effective method for such studies. However, this technique requires the use of suitable reference genes for data normalization. Here, we evaluate the suitability of six reference genes (18S, ACTB, B2M, GAPDH, HPRT1 and TBP) using samples from the rotator cuff tendons of 28 individuals with tendon tears (3 tendons regions) and 8 controls (2 tendon regions); for the tear patients, we evaluated ruptured and non-ruptured tendon samples. The stability of the candidate reference genes was determined using the NormFinder, geNorm, BestKeeper and DataAssist software packages. Overall, HPRT1 was the best single reference gene, and HPRT1+TBP composed the best pair and HPRT1+TBP+ACTB composed the best trio of reference genes from the analysis of different groups, including the simultaneous analysis of all tissue samples. To identify the optimal combination of reference genes, we evaluated the expression of COL1A1 and COL3A1, and no obvious differences were observed when using 2, 3 or 4 reference genes for most of the analyses. However, COL3A1 expression differed between ruptured and non-ruptured (posterior superior region) tendons of patients only when normalized by HPRT1+TBP+B2M and HPRT1+TBP. On the other hand, the comparison between these two groups using the best trio of reference genes (HPRT1+TBP+ACTB) and 4 reference genes did not revealed a significant difference in COL3A1 expression. Consequently, the use of suitable reference genes for a reliable gene expression evaluation by RT-qPCR should consider the type of tendon samples investigated. HPRT1+TBP+ACTB seems to be the best combination of reference genes for the analysis of involving different tendon samples of individuals with rotator cuff tears. PMID:25768100

  5. Severe atrophy and fatty degeneration of the infraspinatus muscle due to isolated infraspinatus tendon tear.

    PubMed

    Kolbe, Amy B; Collins, Mark S; Sperling, John W

    2012-01-01

    Atrophy of both the supraspinatus and infraspinatus muscles is usually caused by chronic rotator cuff tear, but may also derive from suprascapular nerve entrapment at the spinoglenoid notch. Isolated infraspinatus muscle atrophy is uncommon, and typically associates with suprascapular nerve entrapment occurring distal to the spinoglenoid notch. However, isolated atrophy of the infraspinatus muscle due to insertional tear of the infraspinatus tendon may also occur. We present a case of a 43-year-old male with isolated infraspinatus muscle atrophy and fatty degeneration following an isolated full-thickness infraspinatus tendon tear at the insertion site on the humerus. While it is important to rule out other causes of infraspinatus muscle atrophy, such as concomitant rotator cuff tendon/muscle pathology or suprascapular nerve palsy, we present this case to increase awareness of this uncommon clinical presentation and the potential implications for treatment. PMID:21918868

  6. The influence of age, delay of repair, and tendon involvement in acute rotator cuff tears

    PubMed Central

    2011-01-01

    Background and purpose Few authors have considered the outcome after acute traumatic rotator cuff tears in previously asymptomatic patients. We investigated whether delay of surgery, age at repair, and the number of cuff tendons involved affect the structural and clinical outcome. Patients and methods 42 patients with pseudoparalysis after trauma and no previous history of shoulder symptoms were included. A full-thickness tear in at least 1 of the rotator cuff tendons was diagnosed in all patients. Mean time to surgery was 38 (6–91) days. Follow-up at a mean of 39 (12–108) months after surgery included ultrasound, plain radiographs, Constant-Murley score, DASH score, and western Ontario rotator cuff (WORC) score. Results At follow-up, 4 patients had a full-thickness tear and 9 had a partial-thickness tear in the repaired shoulder. No correlation between the structural or clinical outcome and the time to repair within 3 months was found. The patients with a tendon defect at follow-up had a statistically significantly lower Constant-Murley score and WORC index in the injured shoulder and were significantly older than those with intact tendons. The outcomes were similar irrespective of the number of tendons repaired. Interpretation A delay of 3 months to repair had no effect on outcome. The patients with cuff defects at follow-up were older and they had a worse clinical outcome. Multi-tendon injury did not generate worse outcomes than single-tendon tears at follow-up. PMID:21434791

  7. Isolated tear of the pectoralis minor tendon in a high school football player.

    PubMed

    Li, Xinning; Gorman, Matthew T; Dines, Joshua S; Limpisvasti, Orr

    2012-08-01

    Multiple pectoralis major tendon tears have been reported in the literature; however, isolated rupture of the pectoralis minor tendon is rare and has been reported 3 times (4 patients).This article describes a case of an isolated pectoralis minor tendon tear in a male high school football player after a traumatic injury. The patient was injured while making a tackle and leading with his arm and chest. He presented with left anterior shoulder and chest wall pain with direct tenderness on palpation over the coracoid. Magnetic resonance imaging of the chest revealed an isolated tear of the pectoralis minor tendon with slight retraction and significant edema in the muscle belly. The patient returned to full activities after conservative management.Although rare, the diagnosis of pectoralis minor tendon rupture should be considered in patients who sustain a contact injury to the shoulder with tenderness on palpation over the coracoid. The mechanism of injury can be related to a direct anterior force to the shoulder, forced external rotation of the arm in slight abduction, or with the arm in extension and shoulder in flexion (eg, blocking in football). The diagnosis can be confirmed with magnetic resonance imaging when edema exists on the medial aspect of the coracoid and extends into the muscle belly. Physical therapy with scapular stabilization exercises and avoidance of abduction and active adduction can be successful in returning these patients to their previous activity levels. PMID:22868619

  8. Latissimus dorsi tendon transfer for massive irreparable cuff tears: an anatomic study.

    PubMed

    Morelli, Moreno; Nagamori, Jun; Gilbart, Michael; Miniaci, Anthony

    2008-01-01

    The purpose of this study was to describe landmarks for latissimus dorsi tendon transfer in massive irreparable tears of the rotator cuff. Nine pairs of embalmed cadaveric shoulders were dissected. Crucial structures were identified, and their relationship with various bony and soft-tissue reference points was documented. Identification of the dense fibrous band, at the confluence of the teres major and latissimus dorsi musculotendinous unit, facilitates localization of the radial nerve, which crosses deep to this landmark. The axillary nerve can be seen to exit the quadrangular space 27 mm medial to the latissimus dorsi insertion into the proximal humerus, whereas the thoracodorsal neurovascular pedicle inserts into the latissimus dorsi 110 mm from the humeral tendon's humeral attachment. Harvest of the latissimus dorsi tendon can be safely accomplished by identifying the dense fibrous band and releasing the tendon within 2 cm of its humeral attachment. PMID:18069017

  9. Semimembranosus tendon avulsion fracture of the posteromedial tibial plateau associated with posterior cruciate ligament tear and capsular rupture.

    PubMed

    Khoshnoodi, Pooria; Tehranzadeh, Arash D; Dunn, James M; Tehranzadeh, Jamshid

    2014-02-01

    Semimembranosus tendon avulsion fractures are an uncommon occurrence and are often associated with anterior cruciate ligament (ACL) and medial meniscus tears. We present the imaging features of an unusual case of semimembranosus avulsion fracture of the posteromedial tibial plateau associated with posterior cruciate ligament (PCL) tear, medial meniscus tear, and capsular rupture in a 26-year-old man with a football injury. PMID:24026070

  10. Acute tear of the fascia cruris at the attachment to the Achilles tendon: a new diagnosis

    PubMed Central

    Webborn, Nick; Morrissey, Dylan; Sarvananthan, Kasthuri; Chan, Otto

    2015-01-01

    Background The fascia cruris encloses the posterior structures of the calf and connects to the paratenon and the Achilles tendon. We describe the clinical presentation, ultrasound imaging characteristics and the time to the recovery of tears of the fascia cruris at the attachment to the Achilles tendon. Methods Retrospective review of 11 tears of the fascia cruris in the different legs as separate events in 9 patients (6 male and 3 female, mean age 35.52?years, range 11–48) identified using diagnostic ultrasound, after presenting with Achillodynia. Results 11 participants presented at a mean of 4.5?weeks (range 0.5–12) after onset of symptoms. The left Achilles was more commonly injured than the right (7?:?4) and the lateral side more than the medial (6?:?4) with one case with medial and lateral presentation. Clinically, there was swelling and tenderness over the medial or lateral border in the mid to upper portion of the Achilles. 7 of the 11 (63.6%) had functional overpronation. Ultrasound appearances of a tear were identified as hypoechoic area extending from the medial or lateral border of the Achilles extending along the anatomical plane of the fascia cruris. Average return to activity was 5.2?weeks (range 1–22). Participants presenting later had longer recovery but all participants returned to full activity (r=0.4). Conclusions This is the first description of the clinical details and sonographic findings of a tear to the fascia cruris at its attachment to the Achilles tendon. This needs to be considered as a cause of Achillodynia in athletes as recognition will affect the management. PMID:25202137

  11. Clinical results of a surgical technique using endobuttons for complete tendon tear of pectoralis major muscle: report of five cases

    PubMed Central

    2011-01-01

    Background We herein describe a surgical technique for the repair of complete tear of the pectoralis major (PM) tendon using endobuttons to strengthen initial fixation. Methods Five male patients (3 judo players, 1 martial arts player, and 1 body builder) were treated within 2 weeks of sustaining complete tear of the PM tendon. Average age at surgery and follow-up period were 28.4 years (range, 23-33) and 28.8 months (range, 24-36). A rectangular bone trough (about 1 × 4 cm) was created on the humerus at the insertion of the distal PM tendon. The tendon stump was introduced into this trough, and fixed to the reverse side of the humeral cortex using endobuttons and non-absorbable suture. Clinical assessment of re-tear was examined by MRI. Shoulder range of motion (ROM), outcome of treatment, and isometric power were measured at final follow-up. Results There were no clinical re-tears, and MRI findings also showed continuity of the PM tendon in all cases at final follow-up. Average ROM did not differ significantly between the affected and unaffected shoulders. The clinical outcomes at final follow-up were excellent (4/5 cases) or good (1/5). In addition, postoperative isometric power in horizontal flexion of the affected shoulder showed complete recovery when compared with the unaffected side. Conclusions Satisfactory outcomes could be obtained when surgery using the endobutton technique was performed within 2 weeks after complete tear of the PM tendon. Therefore, our new technique appears promising as a useful method to treat complete tear of the PM tendon. PMID:21955511

  12. Tendon transfer for irreparable rotator cuff tears: indications and surgical rationale

    PubMed Central

    Merolla, Giovanni; Chillemi, Claudio; Franceschini, Vincenzo; Cerciello, Simone; Ippolito, Giorgio; Paladini, Paolo; Porcellini, Giuseppe

    2014-01-01

    Summary Background: treatment of symptomatic irreparable rotator cuff tears is extremely challenging because, at present, there are no ideal solutions to this problem. Many patients respond favorably to nonsurgical treatment. However, when conservative measures fail to improve the patient’s pain and disability, surgery should be considered. Methods: different surgical techniques are available and the choice of the most appropriate procedure depends on the presenting symptoms, age of the patient, functional demand, medical comorbidities, joint stability and presence of arthritic changes. The transposition of the surrounding muscles to replace the rotator cuff function represents a viable option in the treatment of younger patients without glenohumeral osteoarthritis and with severe functional limitation. Purpose: aim of this study is to give an overview of the currently available evidence regarding tendon transfer procedures for irreparable rotator cuff tears. PMID:25767779

  13. Effect of tear size, corticosteroids and subacromial decompression surgery on the hierarchical structural properties of torn supraspinatus tendons

    PubMed Central

    Tilley, J. M. R.; Murphy, R. J.; Chaudhury, S.; Czernuszka, J. T.; Carr, A. J.

    2014-01-01

    Objectives The effects of disease progression and common tendinopathy treatments on the tissue characteristics of human rotator cuff tendons have not previously been evaluated in detail owing to a lack of suitable sampling techniques. This study evaluated the structural characteristics of torn human supraspinatus tendons across the full disease spectrum, and the short-term effects of subacromial corticosteroid injections (SCIs) and subacromial decompression (SAD) surgery on these structural characteristics. Methods Samples were collected inter-operatively from supraspinatus tendons containing small, medium, large and massive full thickness tears (n = 33). Using a novel minimally invasive biopsy technique, paired samples were also collected from supraspinatus tendons containing partial thickness tears either before and seven weeks after subacromial SCI (n = 11), or before and seven weeks after SAD surgery (n = 14). Macroscopically normal subscapularis tendons of older patients (n = 5, mean age = 74.6 years) and supraspinatus tendons of younger patients (n = 16, mean age = 23.3) served as controls. Ultra- and micro-structural characteristics were assessed using atomic force microscopy and polarised light microscopy respectively. Results Significant structural differences existed between torn and control groups. Differences were identifiable early in the disease spectrum, and increased with increasing tear size. Neither SCI nor SAD surgery altered the structural properties of partially torn tendons seven weeks after treatment. Conclusions These findings may suggest the need for early clinical intervention strategies for torn rotator cuff tendons in order to prevent further degeneration of the tissue as tear size increases. Further work is required to establish the long-term abilities of SCI and SAD to prevent, and even reverse, such degeneration. Cite this article: Bone Joint Res 2014;3:252–61. PMID:25106417

  14. Tears

    MedlinePLUS

    ... as those salty drops that fall from your eyes when you cry. Actually, your tears clean your eyes every time you blink. Tears also keep your eyes moist, which is important for your vision. Tear ...

  15. Effect of Return to Overuse Activity Following an Isolated Supraspinatus Tendon Tear on Adjacent Intact Tendons and Glenoid Cartilage in a Rat Model

    PubMed Central

    Reuther, Katherine E.; Thomas, Stephen J.; Sarver, Joseph J.; Tucker, Jennica J.; Lee, Chang-Soo; Gray, Chancellor F.; Glaser, David L.; Soslowsky, Louis J.

    2013-01-01

    Rotator cuff tears are common conditions that can alter shoulder mechanics and may lead to damage of intact joint tissues. These injuries are of particular concern in populations who perform tasks requiring repetitive overhead activity (e.g., athletes and laborers) and who are likely to return to aggressive pre-injury activity levels despite limited understanding of the potentially damaging effects on the remaining tissues. Therefore, we investigated the effect of returning to overuse activity following a supraspinatus tear on shoulder function and the mechanical properties of the remaining intact tendons and glenoid cartilage. Forty rats underwent 4 weeks of overuse activity to create a tendinopathic condition followed by detachment of the supraspinatus tendon and were then randomized into two groups: continued overuse or cage activity. Ambulatory measurements were performed throughout the 8 weeks prior to euthaniasia, and properties of the adjacent tendons and cartilage were evaluated. Results demonstrated that shoulder function was not compromised in the return to overuse group. However, alterations of the glenoid cartilage and biceps tendon properties occurred. Our results help define the contributory roles of common mechanical injury mechanisms and provide a framework by which physicians could better prescribe long-term treatment strategies for patients. PMID:23280495

  16. Effect of return to overuse activity following an isolated supraspinatus tendon tear on adjacent intact tendons and glenoid cartilage in a rat model.

    PubMed

    Reuther, Katherine E; Thomas, Stephen J; Sarver, Joseph J; Tucker, Jennica J; Lee, Chang-Soo; Gray, Chancellor F; Glaser, David L; Soslowsky, Louis J

    2013-05-01

    Rotator cuff tears are common conditions that can alter shoulder mechanics and may lead to damage of intact joint tissues. These injuries are of particular concern in populations who perform tasks requiring repetitive overhead activity (e.g., athletes and laborers) and who are likely to return to aggressive pre-injury activity levels despite limited understanding of the potentially damaging effects on the remaining tissues. Therefore, we investigated the effect of returning to overuse activity following a supraspinatus tear on shoulder function and the mechanical properties of the remaining intact tendons and glenoid cartilage. Forty rats underwent 4 weeks of overuse activity to create a tendinopathic condition followed by detachment of the supraspinatus tendon and were then randomized into two groups: continued overuse or cage activity. Ambulatory measurements were performed throughout the 8 weeks prior to euthaniasia, and properties of the adjacent tendons and cartilage were evaluated. Results demonstrated that shoulder function was not compromised in the return to overuse group. However, alterations of the glenoid cartilage and biceps tendon properties occurred. Our results help define the contributory roles of common mechanical injury mechanisms and provide a framework by which physicians could better prescribe long-term treatment strategies for patients. PMID:23280495

  17. Clinics in diagnostic imaging (151). Acromioclavicular joint geyser sign with chronic full-thickness supraspinatus tendon (SST) tear.

    PubMed

    Khor, Andrew Yu Keat; Wong, Steven Bak Siew

    2014-02-01

    An 82-year-old man presented with neck pain, right upper limb radiculopathy and right shoulder pain. Physical examination revealed a soft lump over the right shoulder joint, as well as reduced range of shoulder movements. On magnetic resonance imaging, the soft lump was shown to be a cystic mass over the acromioclavicular joint and was related to a full-thickness supraspinatus tendon tear. This is the classic geyser sign. The pathophysiology and clinical features of the geyser sign, and its imaging features with various imaging modalities, are discussed. PMID:24570312

  18. Clinics in diagnostic imaging (151). Acromioclavicular joint geyser sign with chronic full-thickness supraspinatus tendon (SST) tear.

    PubMed Central

    Khor, Andrew Yu Keat; Wong, Steven Bak Siew

    2014-01-01

    An 82-year-old man presented with neck pain, right upper limb radiculopathy and right shoulder pain. Physical examination revealed a soft lump over the right shoulder joint, as well as reduced range of shoulder movements. On magnetic resonance imaging, the soft lump was shown to be a cystic mass over the acromioclavicular joint and was related to a full-thickness supraspinatus tendon tear. This is the classic geyser sign. The pathophysiology and clinical features of the geyser sign, and its imaging features with various imaging modalities, are discussed. PMID:24570312

  19. Comparison of Medial and Lateral Meniscus Root Tears.

    PubMed

    Koo, Ji Hyun; Choi, Sang-Hee; Lee, Seung Ah; Wang, Joon Ho

    2015-01-01

    The meniscus root plays an essential role in maintaining the circumferential hoop tension and preventing meniscal displacement. Studies on meniscus root tears have investigated the relationship of osteoarthritis and an anterior cruciate ligament tear. However, few studies have directly compared the medial and lateral root tears. To assess the prevalence of meniscal extrusion and its relationship with clinical features in medial and lateral meniscus root tears, we performed a retrospective review of the magnetic resonance imaging (MRI) results of 42 knee patients who had meniscus posterior horn root tears and who had undergone arthroscopic operations. The presence of meniscal extrusion was evaluated and the exact extent was measured from the tibial margin. The results were correlated with arthroscopic findings. Clinical features including patients' ages, joint abnormalities, and previous trauma histories were evaluated. Twenty-two patients had medial meniscus root tears (MMRTs) and twenty patients had lateral meniscus root tears (LMRTs). Meniscal extrusion was present in 18 MMRT patients and one LMRT patient. The mean extent of extrusion was 4.2mm (range, 0.6 to 7.8) in the MMRT group and 0.9mm (range, -1.9 to 3.4) in the LMRT group. Five patients with MMRT had a history of trauma, while 19 patients with LMRT had a history of trauma. Three patients with MMRT had anterior cruciate ligament (ACL) tears, while 19 patients with LMRT had ACL tears. The mean age of the patients was 52 years (range: 29-71 years) and 30 years (range: 14-62 years) in the MMRT and LMRT group, respectively. There was a significant correlation between a MMRT and meniscal extrusion (p<0.0001), and between an ACL tear and LMRT (p<0.0001). A history of trauma was significantly common in LMRT (p<0.0001). LMRT patients were significantly younger than MMRT patients (p<0.0001). Kellgren-Lawrence (K-L) grade differed significantly between MMRT and LMRT group (p<0.0001). Meniscal extrusion is common in patients with MMRTs. However, it is rare in patients with LMRTs, which are more commonly associated with a history of trauma and ACL tears. PMID:26488288

  20. Comparison of Medial and Lateral Meniscus Root Tears

    PubMed Central

    Koo, Ji Hyun; Choi, Sang-Hee; Lee, Seung Ah; Wang, Joon Ho

    2015-01-01

    The meniscus root plays an essential role in maintaining the circumferential hoop tension and preventing meniscal displacement. Studies on meniscus root tears have investigated the relationship of osteoarthritis and an anterior cruciate ligament tear. However, few studies have directly compared the medial and lateral root tears. To assess the prevalence of meniscal extrusion and its relationship with clinical features in medial and lateral meniscus root tears, we performed a retrospective review of the magnetic resonance imaging (MRI) results of 42 knee patients who had meniscus posterior horn root tears and who had undergone arthroscopic operations. The presence of meniscal extrusion was evaluated and the exact extent was measured from the tibial margin. The results were correlated with arthroscopic findings. Clinical features including patients’ ages, joint abnormalities, and previous trauma histories were evaluated. Twenty-two patients had medial meniscus root tears (MMRTs) and twenty patients had lateral meniscus root tears (LMRTs). Meniscal extrusion was present in 18 MMRT patients and one LMRT patient. The mean extent of extrusion was 4.2mm (range, 0.6 to 7.8) in the MMRT group and 0.9mm (range, -1.9 to 3.4) in the LMRT group. Five patients with MMRT had a history of trauma, while 19 patients with LMRT had a history of trauma. Three patients with MMRT had anterior cruciate ligament (ACL) tears, while 19 patients with LMRT had ACL tears. The mean age of the patients was 52 years (range: 29–71 years) and 30 years (range: 14–62 years) in the MMRT and LMRT group, respectively. There was a significant correlation between a MMRT and meniscal extrusion (p<0.0001), and between an ACL tear and LMRT (p<0.0001). A history of trauma was significantly common in LMRT (p<0.0001). LMRT patients were significantly younger than MMRT patients (p<0.0001). Kellgren-Lawrence (K-L) grade differed significantly between MMRT and LMRT group (p<0.0001). Meniscal extrusion is common in patients with MMRTs. However, it is rare in patients with LMRTs, which are more commonly associated with a history of trauma and ACL tears. PMID:26488288

  1. Rotator Cuff Tears

    MedlinePLUS

    ... can stress your rotator cu? muscles and tendons. Baseball, tennis, rowing, and weightli ing are examples of ... vulnerable to overuse tears, particularly tennis players and baseball pitchers. Painters, carpenters, and others who do overhead ...

  2. Comparison of Three-Dimensional Isotropic and Two-Dimensional Conventional Indirect MR Arthrography for the Diagnosis of Rotator Cuff Tears

    PubMed Central

    Lee, Ji Hyun; Jee, Sukkyung; Kwon, Jong Won; Cha, Jang Gyu; Yoo, Jae Chul

    2014-01-01

    Objective To compare the accuracy between a three-dimensional (3D) indirect isotropic T1-weighted fast spin-echo (FSE) magnetic resonance (MR) arthrography and a conventional two-dimensional (2D) T1-weighted sequences of indirect MR arthrography for diagnosing rotator cuff tears. Materials and Methods The study was approved by our Institutional Review Board. In total, 205 patients who had undergone indirect shoulder MR arthrography followed by arthroscopic surgery for 206 shoulders were included in this study. Both conventional 2D T1-weighted FSE sequences and 3D isotropic T1-weighted FSE sequence were performed in all patients. Two radiologists evaluated the images for the presence of full- or partial-thickness tears in the supraspinatus-infraspinatus (SSP-ISP) tendons and tears in the subscapularis (SSC) tendons. Using the arthroscopic findings as the reference standard, the diagnostic performances of both methods were analyzed by the area under the receiver operating characteristic curve (AUC). Results Arthroscopy confirmed 165 SSP-ISP tendon tears and 103 SSC tendon tears. For diagnosing SSP-ISP tendon tears, the AUC values were 0.964 and 0.989 for the 2D sequences and 3D T1-weighted FSE sequence, respectively, in reader I and 0.947 and 0.963, respectively, in reader II. The AUC values for diagnosing SSC tendon tears were 0.921 and 0.925, respectively, for reader I and 0.856 and 0.860, respectively, for reader II. There was no significant difference between the AUC values of the 2D and 3D sequences in either reader for either type of tear. Conclusion 3D indirect isotropic MR arthrography with FSE sequence and the conventional 2D arthrography are not significantly different in terms of accuracy for diagnosing rotator cuff tears. PMID:25469089

  3. Distal Triceps Tendon Injuries.

    PubMed

    Keener, Jay D; Sethi, Paul M

    2015-11-01

    Acute triceps ruptures are an uncommon entity, occurring mainly in athletes, weight lifters (especially those taking anabolic steroids), and following elbow trauma. Accurate diagnosis is made clinically, although MRI may aid in confirmation and surgical planning. Acute ruptures are classified on an anatomic basis based on tear location and the degree of tendon involvement. Most complete tears are treated surgically in medically fit patients. Partial-thickness tears are managed according to the tear severity, functional demands, and response to conservative treatment. We favor an anatomic footprint repair of the triceps to provide optimal tendon to bone healing and, ultimately, functional outcome. PMID:26498552

  4. Clinical and biological aspects of rotator cuff tears

    PubMed Central

    Giai Via, Alessio; De Cupis, Mauro; Spoliti, Marco; Oliva, Francesco

    2013-01-01

    Summary Rotator cuff tears are common and are a frequent source of shoulder pain and disability. A wide variation in the prevalence of rotator cuff tears has been reported. The etiology of rotator cuff tear remains multifactorial and attempts to unify intrinsic and extrinsic theories tried to explain the etiopathogenesis of rotator cuff tears. Knowledge of the etiopathogenesis of rotator cuff tears is important to improve our therapies, surgical techniques and promote tendon repair. Several strategies have been proposed to enhance tendon healing and recently research has focused on regenerative therapies, such as Growth Factors (GFs) and Plasma Rich Platelet (PRP), with high expectations of success. PMID:23888289

  5. [Comparison of local acetylcysteine and artificial tears in the management of dry eye syndrome].

    PubMed

    Pokupec, Rajko; Petricek, Igor; Siki?, Jakov; Bradi?, Mirna; Popovi?-Sui?, Smiljka; Petricek, Goranka

    2005-01-01

    Dry eye syndrome is a common clinical entity causing difficulties to many people, especially the elderly. Standard substitution therapy with artificial tears may frequently prove inadequate, thus any new treatment modality is highly welcome. The syndrome implies lacrimal hyperosmolality, which in turn results in mucus accumulation in the conjunctival sac causing additional irritation. Locally applied acetylcysteine, a mucolytic, regulates mucus secretion and reduces mucus accumulation. The aim of the study was to compare the efficacy of artificial tear therapy and therapy with local acetylcysteine. The study included 32 patients with the symptoms and signs of dry eye attending our department between March 20 and May 9, 2003. All study patients were on long-term substitution therapy with artificial tears. Upon evaluation of subjective discomforts and objective signs, the patients were switched from artificial tear therapy (Isopto-Tears, Alcon, with polyvinyl alcohol as active ingredient) to therapy with locally applied acetylcysteine (Brunac, Bruschettini). All parameters were re-evaluated at 2-week control visit. Thirty of 32 patients (94%) completed the study with control visit. Of these, 18 (60%) patients reported reduction of subjective discomforts, ten (33%) patients observed no change, and two (7%) patients experienced more discomforts with acetylcysteine than with artificial tear therapy. On objective sign evaluation, 12 (40%) patients showed less discomforts, unchanged condition was recorded in 13 (43%) patients, and five (17%) patients had more discomforts as compared with artificial tear therapy. A statistically significant difference (p=0.05) between artificial tear therapy and acetylcysteine therapy was found for the subjective symptom score but not for the objective sign score. Therapy with acetylcysteine proved more efficient than artificial tears in reducing subjective symptoms but had no effect on the objective signs of dry eye syndrome. The advantages of acetylcysteine include more convenient instillation timing (4 times daily) and reduced nocturnal discomfort, whereas shortcomings are the sense of burning on instillation, bad odor, and as yet relatively high price on the Croatian market. PMID:16334742

  6. Tendonitis (image)

    MedlinePLUS

    ... tendon. It can occur as a result of injury, overuse, or with aging as the tendon loses elasticity. Any action that places prolonged repetitive strain on the forearm muscles can cause tendonitis. The ...

  7. Comparison of mechanical properties of rat tibialis anterior tendon evaluated using two different approaches.

    PubMed

    Wu, John Z; Brumfield, Anne; Miller, Gerald R; Metheny, Rebecca; Cutlip, Robert G

    2004-01-01

    Tendon injuries may result in variations of its mechanical properties. The published data of the tendon stiffness of small animals, such as mouse and rat, are exclusively obtained by measuring grip-to-grip (g-t-g) displacement. Local strain concentration and relative sliding of the specimens in the clamps might significantly affect the measured tendon deformation. In the present study, the mechanical properties of the rat tibialis anterior tendon measured using the proposed tendon mark method were compared to those evaluated using the g-t-g displacement method. Five male Sprague Dawley rats ( approximately 418 g) were used in this study. For the proposed method, reference marks were made on the tendons using permanent ink. A microscope video system was customized to observe and record the tendon deformation. Pattern recognition software was developed to obtain the displacement time-histories of the reference marks. The distance between the grips was approximately 7 mm; and the distance between the reference marks used for the data processing was approximately 5 mm. The cross-section areas of the specimens were measured using a custom-made slot gauge and by applying a constant compressive stress (0.15 MPa). The tendons were clamped between two custom-made metal grips and stretched on a testing machine at a constant speed (1 mm/s) up to failure. Throughout the tests, the tendon specimens were submerged in a PBS bath at 22 degrees C. The deformation of the specimens was evaluated using the g-t-g displacement method and the proposed method. The stress/strain curves obtained by using the g-t-g displacement can be characterized by an initial toe zone, a quasi-linear zone, and a final failure stage. The stress/strain curves determined using the proposed method are quite different from those obtained using the g-t-g displacement: it has a smaller toe zone and a stress-hardening transition, over which the tendon stiffness increases dramatically with the increasing strain. The tendon stiffness measured by using the g-t-g displacement method may underestimate the actual mechanical properties of tendon by approximately 43%. PMID:14757949

  8. Comparison of Achilles Tendon Loading Between Male and Female Recreational Runners

    PubMed Central

    Andrew, Greenhalgh; Jonathan, Sinclair

    2014-01-01

    Recreational running is an activity with multiple reported health benefits for both sexes, however, chronic injuries caused by excessive and/or repetitive loading of the Achilles tendon are common. Males have been identified as being at an increased risk of suffering an injury to the Achilles tendon and as such, knowledge of differences in loading between the sexes may provide further information to better understand why this is the case. The aim of the current investigation was to determine whether gender differences in the Achilles tendon load exist in recreational runners. Fifteen male (age 26.74 ± 5.52 years, body height 1.80 ± 0.11 m and body mass 74.22 ± 7.27 kg) and fifteen female (age 25.13 ± 6.39 years, body height 1.68 ± 0.12 m and body mass 67.12 ± 9.11 kg) recreational runners volunteered to take part in the current investigation. Participants completed 10 trials running at 4.0 m·s?1 ±5% striking a force platform (1000 Hz) with their right foot. Ankle joint kinematics were synchronously recorded (250 Hz) using an optoelectric motion capture system. Ankle joint kinetics were computed using Newton-Euler inverse-dynamics. Net external ankle joint moments were then calculated. To estimate Achilles tendon kinetics the plantarflexion moment calculated was divided by an estimated Achilles tendon moment arm of 0.05 m. Differences in Achilles tendon kinetics were examined using independent sample t-tests (p<0.05). The results indicate that males were associated with significantly (p<0.05) greater Achilles tendon loads than females. The findings from this study support the notion that male recreational runners may be at greater risk of Achilles tendon pathology. PMID:25713676

  9. Biomechanical analysis of bursal-sided partial thickness rotator cuff tears

    E-print Network

    Makhsous, Mohsen

    of the supraspinatus tendon to 3/4 tendon width on ten fresh-frozen shoulder specimens. The supra- spinatus muscle of Shoulder and Elbow Surgery Board of Trustees. Keywords: Rotator cuff; rotator cuff tear; supraspinatus contributing to formation of PTCRTs include sub- acromial impingement as a main proponent of bursal sided tears

  10. [Emotional tears].

    PubMed

    Messmer, E M

    2009-07-01

    Emotional tears, an exclusively human means of communication, are complex and rarely the subject of scientific research. The same nerves, receptors, and transmitters seem to be involved in their production as those used for basal and reflex tears. However, stimuli must be received in a cognitive/social context, detected by "induction centers" in the telencephalon, and forwarded to effector centers. Increased concentrations of protein, prolactin, manganese, potassium, and serotonin have been detected in emotional tears. Various theories try to explain the reason for and benefit of emotional tears. A number of factors, such as ethnic group, social status, profession, hormonal situation, gender, and individual threshold, influence whether an individual is a "crier" or a "noncrier." Manipulative tears are a strong weapon for unbalancing other people, and the expression "crocodile tears" is used for both manipulative tears and aberrant gustolacrimal tears. Pathological crying occurs during depression, but it also occurs in the context of central nervous system disease as prolonged crying fits without cause or emotion. Absent emotional tearing is observed in congenital, often syndromal, disorders. PMID:19568753

  11. Analysis of sub-surface towing of tendons and comparison of results using WINPOST and ORCAFLEX 

    E-print Network

    Mendon, Perdoor Mukthi

    2002-01-01

    During tendon towing the pipe is floating in a horizontal plane parallel to the sea-surface unlike the usual vertical slender members like risers, mooring lines, etc where the pipe/cable is perpendicular to the sea-surface. This change in projection...

  12. Antibacterial Activity of Rifamycins for M. Smegmatis with Comparison of Oxidation and Binding to Tear Lipocalin

    PubMed Central

    Staudinger, Tamara; Redl, Bernhard; Glasgow, Ben J.

    2014-01-01

    A mutant of Mycobacterium smegmatis is a potential class I model substitute for Mycobacterium tuberculosis. Because not all of the rifamycins have been tested in this organism, we determined bactericidal profiles for the 6 major rifamycin derivatives. The profiles closely mirrored that established for Mycobacterium tuberculosis. Rifalazil was confirmed to be the most potent rifamycin. Because the tuberculous granuloma presents a harshly oxidizing environment we explored the effects of oxidation on rifamycins. Mass spectrometry confirmed that three of the six major rifamycins showed autoxidation in the presence of trace metals. Oxidation could be monitored by distinctive changes including isosbestic points in the ultraviolet-visible spectrum. Oxidation of rifamycins abrogated antimycobacterial activity in Mycobacterium smegmatis. Protection from autoxidation was conferred by binding susceptible rifamycins to tear lipocalin, a promiscuous lipophilic protein. Rifalazil was not susceptible to autoxidation but was insoluble in aqueous. Solubility was enhanced when complexed to tear lipocalin and was accompanied by a spectral red shift. The positive solvatochromism was consistent with robust molecular interaction and binding. Other rifamycins also formed a complex with lipocalin, albeit to a lesser extent. Protection from oxidation and enhancement of solubility with protein binding may have implications for delivery of select rifamycin derivatives. PMID:24530503

  13. Meniscus tears

    MedlinePLUS

    ... inner (medial) meniscal tear. For an Apley's compression test, the health care provider will have you lie on your stomach ... may indicate an inner (medial) meniscal tear. The health care ... injury. A test for excess joint fluid is positive in meniscal ...

  14. Full thickness tears: retaining the cuff.

    PubMed

    Osti, Leonardo; Rizzello, Giacomo; Panascì, Manlio; Denaro, Vincenzo; Maffulli, Nicola

    2011-12-01

    Repair of rotator cuff tears is technically challenging. Full thickness rotator cuff tears have no potential for spontaneous healing, no reliable tendons substitutes are available, and their management is only partially understood. Many factors seem to contribute to the final outcome, and considerable variations in the decision-making process exist. For these reasons, decisions are often taken on the basis of surgeon's clinical experience. Accurate and prompt diagnosis is fundamental to guide correct management, and the tear pattern should be carefully evaluated to planning the most appropriate repair. PMID:22089291

  15. Tear System

    MedlinePLUS

    ... the eyelids. A thorough examination by an ophthalmic plastic surgeon can determine the cause of tearing and ... a dacryocystorhinostomy or DCR, look for an ophthalmic plastic reconstructive and cosmetic surgeon who specializes in the ...

  16. Meniscus Tears

    MedlinePLUS

    ... common sports injury, particularly in contact sports like football and hockey. Meniscus tears can range from minor ... knee while playing a contact sport, such as football, hockey, or rugby, where the knee may be ...

  17. Comparison of femoral fixation methods for anterior cruciate ligament reconstruction with patellar tendon graft: a mechanical analysis in porcine knees.

    PubMed

    Milano, Giuseppe; Mulas, Pier Damiano; Ziranu, Fabio; Deriu, Laura; Fabbriciani, Carlo

    2007-06-01

    The aim of the present study was to evaluate the structural properties of femur-patellar tendon graft complex in anterior cruciate ligament (ACL) reconstruction using different femoral fixation devices. Type of study is biomechanical testing. An ACL reconstruction was performed on 40 cadaver porcine knees, using patellar tendon (PT) graft. Specimens were divided into four groups according to the femoral fixation: interference absorbable screw (Group A), metallic setscrew (Group B), absorbable pins (Group C), and a combination of metallic setscrew and pin (Group D). Other ten knees were used as controls. On each sample, a cyclic loading test, then a load-to-failure test were performed. Elongation after 1,000 loading cycles, ultimate failure load, yield load, stiffness, deformation at the yield point, and mode of failure were recorded. Kruskal-Wallis test and Tukey test were used to compare the differences between groups. The lowest mean elongation after 1,000 load cycles was observed for Group B (1.7 +/- 1.4 mm) and D (1.2 +/- 0.3 mm). Ultimate failure load of Group D (1,021.8 +/- 199.4 N) was comparable with that of normal ACL (1,091.2 +/- 193.3 N) and PT graft (1,140.6 +/- 285.7 N). All other groups were lower than the controls. For mean stiffness, all the groups, excepting for Group D (172.8 +/- 40.4 N/mm), were significantly lower than PT control group (216 +/- 78.4 N/mm). Mode of failure was graft pullout for Groups A and B, distal pin breakage for Group C, and midsubstance graft rupture in 80% of the cases for Group D. Only combined compression and suspension fixation did not show significantly different structural properties in comparison with normal ACL and PT graft. Furthermore, it showed no risk of graft pullout or hardware breakdown in comparison with other fixation devices. PMID:17295042

  18. Glenohumeral joint motion after subscapularis tendon repair: an analysis of cadaver shoulder models

    PubMed Central

    2014-01-01

    Background As for the surgical treatment of the rotator cuff tears, the subscapularis tendon tears have recently received much attention for the mini-open or arthroscopic repair. The results of surgical repair for the subscapularis tendon tear are satisfactory, but the range of external rotation is reported to be restricted after the repair. The purpose of this study was to evaluate the range of glenohumeral joint motion after repairs of various sizes of subscapularis tendon tears. Methods Using eight fresh frozen human cadaveric shoulders (mean age at death, 81.5 years), three sizes of subscapularis tendon tear (small, medium, and large) were made and then repaired. With the scapula fixed to the wooden jig, the end-range of glenohumeral motion was measured with passive movement applied through 1.0-Nm torque in the directions of scapular elevation, flexion, abduction, extension, horizontal abduction, and horizontal adduction. The passive end-ranges of external and internal rotation in various positions with rotational torque of 1.0 Nm were also measured. Differences in the ranges among the three type tears were analyzed. Results As tear size increased, range of glenohumeral motion in horizontal abduction after repair decreased gradually and was significantly decreased with the large size tear (P?tear size in every glenohumeral position. The prominent decrease in external rotation (around 40° reduction from intact shoulders) was observed in shoulders after repair of large size tear at 30° to 60° of scapular elevation and abduction. Conclusions As the size of the subscapularis tendon tear increased, the passive ranges of horizontal abduction and external rotation of the glenohumeral joint after repair decreased significantly. In shoulders with a subscapularis tendon tear, it is necessary to consider the reduction of external rotation depending on tear size. PMID:24885276

  19. Toward an Animal Model of the Human Tear Film: Biochemical Comparison of the Mouse, Canine, Rabbit, and Human Meibomian Lipidomes

    PubMed Central

    Butovich, Igor A.; Lu, Hua; McMahon, Anne; Eule, J. Corinna

    2012-01-01

    Purpose. Secretions that are produced by meibomian glands (also known as meibum) are a major source of lipids for the ocular surface of humans and animals alike. Many animal species have been evaluated for their meibomian lipidomes. However, there have been a very small number of studies in which the animals were compared with humans side by side. Therefore, the purpose of this study was to compare meibum collected from humans and three typical laboratory animals, canines, mice, and rabbits, for their meibomian lipid composition in order to determine which animal species most resembles humans. Methods. High pressure liquid chromatography (HPLC) and gas-liquid chromatography (GLC) in combination with mass spectrometry were used to evaluate lipidomes of all tested species. Results. Among three tested animal species, mice were found to be the closest match to humans in terms of their meibomian lipidomes, while canines were the second closest species. The lipids of these three species were close to each other structurally and, for most lipid classes, quantitatively. The rabbit meibomian lipidome, on the other hand, was vastly different from lipidomes of all other tested species. Interestingly, a previously described class of lipids, acylated omega-hydroxy fatty acids (OAHFA), was found to be present in every tested species as the major amphiphilic component of meibum. Conclusions. Our side by side comparison of the rabbit and the human meibum demonstrated their vast differences. Thus, the rabbit seems to be a poor animal model of the human tear film, at least when studying its biochemistry and biophysics. PMID:22918629

  20. Comma Sign–Directed Repair of Anterosuperior Rotator Cuff Tears

    PubMed Central

    Dilisio, Matthew F.; Neyton, Lionel

    2014-01-01

    The comma sign was described as an arthroscopic landmark to identify the torn subscapularis stump to mobilize and repair the tendon in anterosuperior rotator cuff tears. It was hypothesized that it is composed of the humeral attachments of the superior glenohumeral and coracohumeral ligaments. This arthroscopic finding has since become accepted orthopaedic nomenclature pathognomonic for subscapularis tears and a key component of subscapularis tear classification. We propose an alternative theory of the pathoanatomy of the comma sign in anterosuperior rotator cuff tears and present the technique of comma sign–directed repairs of combined subscapularis and supraspinatus lesions. After appropriate releases, tendon-to-tendon repair of the distal-superior aspect of the comma sign to the upper border of the remnant subscapularis results in anatomic re-creation of the intra-articular portion of the torn subscapularis with concomitant reduction of the anterior leading edge of the supraspinatus and reconstitution of the rotator cable complex. A tension-free, single-anchor subscapularis repair is then performed to secure the tendon to the lesser tuberosity. After subscapularis repair, the supraspinatus that was previously retracted to the glenoid rim takes the appearance of a crescent-type tear that is easily approximated to its anatomic insertion. PMID:25685676

  1. Traumatic Supraspinatus Tears in Patients Younger Than 25 Years.

    PubMed

    Dilisio, Matthew F; Noel, Curtis R; Noble, Jeffrey S; Bell, Robert H

    2015-07-01

    Traumatic rotator cuff tears in patients younger than 25 years are rare events, with few reports in the literature. When compared with the more mature shoulder, the young, healthy supraspinatus tendon is a robust tendon that is able to absorb a significant amount of energy before tendon failure. Therefore, the diagnosis of a rotator cuff tear can be often overlooked in this population due to the patient's age. This is a report of traumatic supraspinatus repairs in patients younger than 25 years. Nine patients younger than 25 years were identified with a posttraumatic supraspinatus tear as visualized during routine diagnostic shoulder arthroscopy. These 9 patients represented 0.33% of all rotator cuff repairs during a 9-year period. Average patient age was 19.1 years (±3.7 years; range, 13 to 25 years). Magnetic resonance imaging failed to diagnose a rotator cuff tear in 50% of the patients. Mean delay from injury to surgery was 6.6 months. All tears were arthroscopically repaired. Concomitant anterior instability pathology was demonstrated among 66.7% of the patients. No complications were reported. At latest follow-up, all patients reported minimal to no shoulder pain and were tolerating strenuous work, activities, and sports without significant complaints. Even with advanced imaging, the diagnosis of a rotator cuff tear can often be missed in this patient population. Although clinical outcomes can be good, care must be taken to broaden the diagnostic differential in young patients with posttraumatic shoulder pain. PMID:26186327

  2. Effects of rotator cuff tears on muscle moment arms: a computational study.

    PubMed

    Adams, Corinne R; Baldwin, Mark A; Laz, Peter J; Rullkoetter, Paul J; Langenderfer, Joseph E

    2007-01-01

    Rotator cuff tears cause morphologic changes to cuff tendons and muscles, which can alter muscle architecture and moment arm. The effects of these alterations on shoulder mechanical performance in terms of muscle force and joint strength are not well understood. The purpose of this study was to develop a three-dimensional explicit finite element model for investigating morphological changes to rotator cuff tendons following cuff tear. The subsequent objectives were to validate the model by comparing model-predicted moment arms to empirical data, and to use the model to investigate the hypothesis that rotator cuff muscle moment arms are reduced when tendons are divided along the force-bearing direction of the tendon. The model was constructed by extracting tendon, cartilage, and bone geometry from the male Visible Human data set. Infraspinatus and teres minor muscle and tendon paths were identified relative to the humerus and scapula. Kinetic and kinematic boundary conditions in the model replicated experimental protocols, which rotated the humerus from 45 degrees internal to 45 degrees external rotation with constant loads on the tendons. External rotation moment arms were calculated for two conditions of the cuff tendons: intact normal and divided tendon. Predicted moment arms were within the 1-99% confidence intervals of experimental data for nearly all joint angles and tendon sub-regions. In agreement with the experimental findings, when compared to the intact condition, predicted moment arms were reduced for the divided tendon condition. The results of this study provide evidence that one potential mechanism for the reduction in strength observed with cuff tear is reduction of muscle moment arms. The model provides a platform for future studies addressing mechanisms responsible for reduced muscle force and joint strength including changes to muscle length-tension operating range due to altered muscle and tendon excursions, and the effects of cuff tear size and location on moment arms and muscle forces. PMID:17597135

  3. The accuracy of “subacromial grind test” in diagnosis of supraspinatus rotator cuff tears

    PubMed Central

    Sawalha, Seif; Fischer, Jochen

    2015-01-01

    Purpose: The aim of this study is to assess the accuracy of a simple clinical test (subacromial grind test) in diagnosing supraspinatus tendon tears. Patients and Methods: The test is considered positive if palpable crepitus or grinding is detected on passive internal and external rotation of the shoulder while abducted in the scapular plane. Data were collected prospectively on 47 patients undergoing shoulder arthroscopy, and the results of the test and arthroscopy compared. Results: During arthroscopy, 17 patients had full thickness (FT) tears of supraspinatus tendon and 10 had partial thickness tears. For any supraspinatus tear, the sensitivity of the test was 63%, specificity 95%, positive predictive value 94%, negative predictive value 66% and overall accuracy 79%. For FT tears, the sensitivity was 82%, specificity 87%, positive predictive value 78%, negative predictive value 90% and overall accuracy 85%. Conclusion: We found that this is a useful single test for diagnosing FT supraspinatus tears. Level of Evidence: Level IV diagnostic study. PMID:25937713

  4. Stem Cell Applications in Tendon Disorders: A Clinical Perspective

    PubMed Central

    Young, Mark

    2012-01-01

    Tendon injuries are a common cause of morbidity and a significant health burden on society. Tendons are structural tissues connecting muscle to bone and are prone to tearing and tendinopathy, an overuse or degenerative condition that is characterized by failed healing and cellular depletion. Current treatments, for tendon tear are conservative, surgical repair or surgical scaffold reconstruction. Tendinopathy is treated by exercises, injection therapies, shock wave treatments or surgical tendon debridement. However, tendons usually heal with fibrosis and scar tissue, which has suboptimal tensile strength and is prone to reinjury, resulting in lifestyle changes with activity restriction. Preclinical studies show that cell therapies have the potential to regenerate rather than repair tendon tissue, a process termed tenogenesis. A number of different cell lines, with varying degrees of differentiation, have being evaluated including stem cells, tendon derived cells and dermal fibroblasts. Even though cellular therapies offer some potential in treating tendon disorders, there have been few published clinical trials to determine the ideal cell source, the number of cells to administer, or the optimal bioscaffold for clinical use. PMID:22448174

  5. Popliteomeniscal fascicle tear: diagnosis and operative technique.

    PubMed

    Shin, Hong-Kwan; Lee, Hee-Sung; Lee, Young-Kuk; Bae, Ki-Cheor; Cho, Chul-Hyun; Lee, Kyung-Jae

    2012-09-01

    The occurrence and the consistency of the popliteomeniscal fascicle between the popliteus tendon and the lateral meniscus have been the subject of debate. It is difficult to diagnose and treat popliteomeniscal fascicle tears. Furthermore, popliteomeniscal fascicle tears are difficult to identify with arthroscopy. This article describes the diagnostic factors for popliteomeniscal fascicle tears and the safe, effective operative techniques that can be used for their treatment. We suggest that popliteomeniscal fascicle tears are diagnosed when the following 3 conditions are confirmed: (1) existence of mechanical symptoms such as pain, locking, and giving way in the lateral compartment of the knee; (2) identification of hypermobility of the lateral meniscus through arthroscopic probing; and (3) occurrence of an osteochondral lesion in the posterior area of the lateral femoral condyle. In the case of popliteomeniscal fascicle tears, the tear area can be repaired with a suture hook and polydioxanone with an all-inside technique. If the joint space is narrowing because of soft-tissue tightness, it can be repaired with a zone-specific cannula through an inside-out technique. PMID:23766962

  6. Artificial tears potpourri: a literature review

    PubMed Central

    Moshirfar, Majid; Pierson, Kasey; Hanamaikai, Kamalani; Santiago-Caban, Luis; Muthappan, Valliammai; Passi, Samuel F

    2014-01-01

    Numerous brands and types of artificial tears are available on the market for the treatment of dysfunctional tear syndrome. Past literature has focused on comparing the components of these products on patient’s clinical improvement. The wide array of products on the market presents challenges to both clinicians and patients when trying to choose between available tear replacement therapies. Different formulations affect patients based on etiology and severity of disease. In order to provide an unbiased comparison between available tear replacement therapies, we conducted a literature review of existing studies and National Institutes of Health clinical trials on commercially available, brand name artificial tears. Outcomes evaluated in each study, as well as the percent of patients showing clinical and symptomatic improvement, were analyzed. Fifty-one studies evaluating different brands of artificial tears, and their efficacy were identified. Out of the 51 studies, 18 were comparison studies testing brand name artificial tears directly against each other. Nearly all formulations of artificial tears provided significant benefit to patients with dysfunctional tear syndrome, but some proved superior to others. From the study data, a recommended treatment flowchart was derived. PMID:25114502

  7. Achilles tendon repair

    MedlinePLUS

    Achilles tendon rupture-surgery; Percutaneous Achilles tendon rupture repair ... To fix your torn Achilles tendon, the surgeon will: Make a cut down the back of your heel Make several small cuts rather than one ...

  8. Rotator cuff tears: An evidence based approach.

    PubMed

    Sambandam, Senthil Nathan; Khanna, Vishesh; Gul, Arif; Mounasamy, Varatharaj

    2015-12-18

    Lesions of the rotator cuff (RC) are a common occurrence affecting millions of people across all parts of the globe. RC tears are also rampantly prevalent with an age-dependent increase in numbers. Other associated factors include a history of trauma, limb dominance, contralateral shoulder, smoking-status, hypercholesterolemia, posture and occupational dispositions. The challenge lies in early diagnosis since a high proportion of patients are asymptomatic. Pain and decreasing shoulder power and function should alert the heedful practitioner in recognizing promptly the onset or aggravation of existing RC tears. Partial-thickness tears (PTT) can be bursal-sided or articular-sided tears. Over the course of time, PTT enlarge and propagate into full-thickness tears (FTT) and develop distinct chronic pathological changes due to muscle retraction, fatty infiltration and muscle atrophy. These lead to a reduction in tendon elasticity and viability. Eventually, the glenohumeral joint experiences a series of degenerative alterations - cuff tear arthropathy. To avert this, a vigilant clinician must utilize and corroborate clinical skill and radiological findings to identify tear progression. Modern radio-diagnostic means of ultrasonography and magnetic resonance imaging provide excellent visualization of structural details and are crucial in determining further course of action for these patients. Physical therapy along with activity modifications, anti-inflammatory and analgesic medications form the pillars of nonoperative treatment. Elderly patients with minimal functional demands can be managed conservatively and reassessed at frequent intervals. Regular monitoring helps in isolating patients who require surgical interventions. Early surgery should be considered in younger, active and symptomatic, healthy patients. In addition to being cost-effective, this helps in providing a functional shoulder with a stable cuff. An easily reproducible technique of maximal strength and sturdiness should by chosen among the armamentarium of the shoulder surgeon. Grade 1 PTTs do well with debridement while more severe lesions mandate repair either by trans-tendon technique or repair following conversion into FTT. Early repair of repairable FTT can avoid appearance and progression of disability and weakness. The choice of surgery varies from surgeon-to-surgeon with arthroscopy taking the lead in the current scenario. The double-row repairs have an edge over the single-row technique in some patients especially those with massive tears. Stronger, cost-effective and improved functional scores can be obtained by the former. Both early and delayed postoperative rehabilitation programmes have led to comparable outcomes. Guarded results may be anticipated in patients in extremes of age, presence of comorbidities and severe tear patters. Overall, satisfactory results are obtained with timely diagnosis and execution of the appropriate treatment modality. PMID:26716086

  9. Rotator cuff tears: An evidence based approach

    PubMed Central

    Sambandam, Senthil Nathan; Khanna, Vishesh; Gul, Arif; Mounasamy, Varatharaj

    2015-01-01

    Lesions of the rotator cuff (RC) are a common occurrence affecting millions of people across all parts of the globe. RC tears are also rampantly prevalent with an age-dependent increase in numbers. Other associated factors include a history of trauma, limb dominance, contralateral shoulder, smoking-status, hypercholesterolemia, posture and occupational dispositions. The challenge lies in early diagnosis since a high proportion of patients are asymptomatic. Pain and decreasing shoulder power and function should alert the heedful practitioner in recognizing promptly the onset or aggravation of existing RC tears. Partial-thickness tears (PTT) can be bursal-sided or articular-sided tears. Over the course of time, PTT enlarge and propagate into full-thickness tears (FTT) and develop distinct chronic pathological changes due to muscle retraction, fatty infiltration and muscle atrophy. These lead to a reduction in tendon elasticity and viability. Eventually, the glenohumeral joint experiences a series of degenerative alterations - cuff tear arthropathy. To avert this, a vigilant clinician must utilize and corroborate clinical skill and radiological findings to identify tear progression. Modern radio-diagnostic means of ultrasonography and magnetic resonance imaging provide excellent visualization of structural details and are crucial in determining further course of action for these patients. Physical therapy along with activity modifications, anti-inflammatory and analgesic medications form the pillars of nonoperative treatment. Elderly patients with minimal functional demands can be managed conservatively and reassessed at frequent intervals. Regular monitoring helps in isolating patients who require surgical interventions. Early surgery should be considered in younger, active and symptomatic, healthy patients. In addition to being cost-effective, this helps in providing a functional shoulder with a stable cuff. An easily reproducible technique of maximal strength and sturdiness should by chosen among the armamentarium of the shoulder surgeon. Grade 1 PTTs do well with debridement while more severe lesions mandate repair either by trans-tendon technique or repair following conversion into FTT. Early repair of repairable FTT can avoid appearance and progression of disability and weakness. The choice of surgery varies from surgeon-to-surgeon with arthroscopy taking the lead in the current scenario. The double-row repairs have an edge over the single-row technique in some patients especially those with massive tears. Stronger, cost-effective and improved functional scores can be obtained by the former. Both early and delayed postoperative rehabilitation programmes have led to comparable outcomes. Guarded results may be anticipated in patients in extremes of age, presence of comorbidities and severe tear patters. Overall, satisfactory results are obtained with timely diagnosis and execution of the appropriate treatment modality. PMID:26716086

  10. Differential growth on sutures of tendon cells derived from torn human rotator cuff.

    PubMed

    Hakimi, Osnat; Chaudhury, Salma; Murphy, Richard; Carr, Andrew

    2012-04-01

    Rotator cuff tendon pathology is proposed to account for 30-70% of all shoulder pain and surgical repair with a nonabsorbable suture is the common option for painful rotator cuff tears that have failed conservative treatment. A number of studies have suggested the beneficial effect of augmenting the repair with implants constructed from polymers used for sutures. Thus, it was of interest to investigate the affinity of tendon-derived fibroblasts, often thought to be the repairing agents of torn tendons, to commonly used sutures. The aim of this comparative study was to evaluate the suitability of these sutures for the construction of a patch by measuring cell survival, proliferation, and migration of human tendon-derived fibroblasts on different sutures. To ensure relevance to the target tissue, cells used in this study were obtained from torn human supraspinatus tendons. An initial comparison of cell proliferation on suture mats showed an overall positive proliferation on polyester (Ethibond) and polydioxanone (PDSII) mats and a reduction of proliferation on vicryl (polyglactin 910) compared to day one. The results also showed that the degradation products of vicryl had a negative effect on cell growth over 10 weeks. Of the commercial sutures selected and tested, Ethibond showed the best performance in terms of cell attachment and increase in biomass. The degradable PDSII also showed good interaction with cells in vitro, but relatively poor cell adhesion. This study provides useful and clinically relevant information, which could help to guide future considerations for candidate materials from which to construct tissue repair patches. PMID:22121052

  11. Popliteus tendon tenosynovitis.

    PubMed

    Mayfield, G W

    1977-01-01

    This series of case suggests that the entity of tenosynovitis of the popliteus tendon is more common than once recognized. A high index of sucpicion and accurate palpation of the lateral aspect of the knee lead one to the diagnosis. Knowledge of this entity may prevent future misdiagnosis of tear of the lateral meniscus and unnecessary meniscectomy as experienced by Helfet, Holden, and myself. There is a definite correlation with activities requiring downhill walking or running. The runners invariably complained of the oneset of symptoms during downhill running rather than uphill running. Back packing enthusiastscomplained of no symptoms for several days after ascending into the mountains, only to experience the symptoms at the end of a long, rapid descent out of the mountains. The pathomechanics of this inflammation of the popliteus tendon is not fully understood. Preliminary analysis of gait movies suggests that in downhill running there is an increased vector to displace the weight-bearing femur forward on the relatively fixed tibia as the knee is increasingly flexed (Fig. 5). Previously mentioned EMG functional studies indicate that the popliteus muscle is active during this weight-bearing phase of gait and may act to retard the femur from forward displacement on the tibia in conjunction with the quadriceps. More specifically, it may help to retard the lateral femoral condyle from rotating forward off the lateral tibial plateau. Downhill running or walking therefore may cause increased stress on the popliteus muscle-tendon unit in an effort to decelerate the body weight against the altered angle of gravitational pull, with resultant tenosynovitis and symptoms. In this series there were no top flight competitive runners. The typical patient was a 31-year-old physician who was jogging 1 to 5 miles and decided to increase his pace and distance, particularly while jogging downhill. The average age of this series of patients (31 years) at the time of onset, coupled with the fact many of these persons were relatively sedentary until stressing the knee by increased activity, suggests that there will be an increasing number of these patients in the future as jogging and running are prescribed for cardiovascular system conditioning. PMID:848633

  12. Use of a Hunter Rod for Staged Reconstruction of Peroneal Tendons.

    PubMed

    Raikin, Steven M; Schick, Faith A; Karanjia, Homyar N

    2016-01-01

    Peroneal tendon pathology is a commonly reported cause of lateral ankle pain. The causes include cavovarus foot type, overuse, chronic tendinosis, peroneal subluxation or dislocation, acute traumatic split tears, and traumatic rupture. The purpose of the present report is to describe an alternative approach for surgical reconstruction of the peroneal tendons in patients when repair might no longer be effective. The use of a Hunter rod was originally described by Hunter in 1971 for 2-stage reconstruction of tendons in the hand. We present a 2-stage surgical technique with the use of a Hunter rod as a temporary implant to stimulate generation of a healthy peroneal tendon sheath to host a flexor hallucis longus tendon transfer. This has proved to be a successful treatment option for patients with severe peroneal tendon damage and scarring along the peroneal tendon sheath. We offer a sample case to illustrate a patient with such indications. PMID:26282362

  13. Subcoracoid impingement and subscapularis tendon: is there any truth?

    PubMed

    Osti, Leonardo; Soldati, Francesco; Del Buono, Angelo; Massari, Leo

    2013-04-01

    Subcoracoid impingement and stenosis have been described related to anterior shoulder pain and subscapularis tendon tears, but the pathogenesis and related treatment of this condition has still not been explained properly. Variability of coracoid morphology has been described and both traumatic and iatrogenic factors can modify it. Some authors referred this to a primary narrow coracohumeral distance with different threshold values defined as increased risk factor for subscapularis and antero-superior RC tear; opposite theories stated that the stenosis is secondary to an anterosuperior translation of the humeral head toward the coracoid due to degenerative changes of the rotator cuff tendons. Limited coracoplasty can be performed when related risk factors are identified; however no clear consensus arises from specific literature review and extensive clinical and instrumental examination of the patient should be performed in order to identify specific risk factors for subscapularis tendon pathology and, subsequently, tailor the proper approach. PMID:23888292

  14. Subcoracoid impingement and subscapularis tendon: is there any truth?

    PubMed Central

    Osti, Leonardo; Soldati, Francesco; Del Buono, Angelo; Massari, Leo

    2013-01-01

    Summary Subcoracoid impingement and stenosis have been described related to anterior shoulder pain and subscapularis tendon tears, but the pathogenesis and related treatment of this condition has still not been explained properly. Variability of coracoid morphology has been described and both traumatic and iatrogenic factors can modify it. Some authors referred this to a primary narrow coracohumeral distance with different threshold values defined as increased risk factor for subscapularis and antero-superior RC tear; opposite theories stated that the stenosis is secondary to an anterosuperior translation of the humeral head toward the coracoid due to degenerative changes of the rotator cuff tendons. Limited coracoplasty can be performed when related risk factors are identified; however no clear consensus arises from specific literature review and extensive clinical and instrumental examination of the patient should be performed in order to identify specific risk factors for subscapularis tendon pathology and, subsequently, tailor the proper approach. PMID:23888292

  15. Blocked tear duct (image)

    MedlinePLUS

    Tears are produced by the lacrimal gland located in the upper outer portion of each eye. Tears drain into a tear duct through a very small opening in the corner of your eye, near your nose. This opening is called the nasolacrimal duct. ...

  16. Massive rotator cuff tears: arthroscopy to arthroplasty.

    PubMed

    Singh, Anshu; Jawa, Andrew; Morman, Monica; Sanofsky, Benjamin; Higgins, Laurence

    2010-01-01

    The understanding of rotator cuff disease has increased exponentially since Codman drew attention to this pathology in the early 1900s. Although challenging, the surgical treatment of massive rotator cuff tears is rational, with treatment decisions based on physical examination, imaging, biologic, and patient factors. Arthroscopy can be used to treat ancillary pain generators, débride necrotic tissue, and possibly restore balance to the force couples about the shoulder. Tendon transfers may be effective in restoring functional strength to irreparable, ineffectual muscle units. Arthroplasty is both a primary treatment and a salvage option. PMID:20415384

  17. Streaming tearing mode

    NASA Technical Reports Server (NTRS)

    Shigeta, M.; Sato, T.; Dasgupta, B.

    1985-01-01

    The magnetohydrodynamic stability of streaming tearing mode is investigated numerically. A bulk plasma flow parallel to the antiparallel magnetic field lines and localized in the neutral sheet excites a streaming tearing mode more strongly than the usual tearing mode, particularly for the wavelength of the order of the neutral sheet width (or smaller), which is stable for the usual tearing mode. Interestingly, examination of the eigenfunctions of the velocity perturbation and the magnetic field perturbation indicates that the streaming tearing mode carries more energy in terms of the kinetic energy rather than the magnetic energy. This suggests that the streaming tearing mode instability can be a more feasible mechanism of plasma acceleration than the usual tearing mode instability.

  18. Decellularized Tendon Extracellular Matrix—A Valuable Approach for Tendon Reconstruction?

    PubMed Central

    Schulze-Tanzil, Gundula; Al-Sadi, Onays; Ertel, Wolfgang; Lohan, Anke

    2012-01-01

    Tendon healing is generally a time-consuming process and often leads to a functionally altered reparative tissue. Using degradable scaffolds for tendon reconstruction still remains a compromise in view of the required high mechanical strength of tendons. Regenerative approaches based on natural decellularized allo- or xenogenic tendon extracellular matrix (ECM) have recently started to attract interest. This ECM combines the advantages of its intrinsic mechanical competence with that of providing tenogenic stimuli for immigrating cells mediated, for example, by the growth factors and other mediators entrapped within the natural ECM. A major restriction for their therapeutic application is the mainly cell-associated immunogenicity of xenogenic or allogenic tissues and, in the case of allogenic tissues, also the risk of disease transmission. A survey of approaches for tendon reconstruction using cell-free tendon ECM is presented here, whereby the problems associated with the decellularization procedures, the success of various recellularization strategies, and the applicable cell types will be thoroughly discussed. Encouraging in vivo results using cell-free ECM, as, for instance, in rabbit models, have already been reported. However, in comparison to native tendon, cells remain mostly inhomogeneously distributed in the reseeded ECM and do not align. Hence, future work should focus on the optimization of tendon ECM decellularization and recolonization strategies to restore tendon functionality. PMID:24710540

  19. Post-translation modification of proteins in tears.

    PubMed

    You, Jingjing; Fitzgerald, Anna; Cozzi, Paul J; Zhao, Zhenjun; Graham, Peter; Russell, Pamela J; Walsh, Bradley J; Willcox, Mark; Zhong, Ling; Wasinger, Valerie; Li, Yong

    2010-06-01

    This is the first 2-DE study using sequential dyes to analyse phospho-, glyco- and total tear protein profiles (Pro-Q Diamond for phosphoprotein, Pro-Q Emerald for glycoprotein and Sypro Ruby for total protein). This method minimised the gel-gel variations, allowing better comparisons among the three profiles and generated a whole map of PTM profiles of tear protein. A novel tear protein, dermcidin, was identified for the first time in this study. The identification of this antimicrobial protein suggests a new model of defence in tears. In addition, we are able to present the first experimental evidence of the presence of glycosylated lipocalin 1 and cystatin S. Nucleobindin 2 was only detected using phospho staining, suggesting it is only phosphorylated in tears. This study provides the groundwork for understanding the PTM of tear proteins and consequently these methods could be useful in the search for biomarkers in tears. PMID:20506419

  20. Peroneal Tendon Injuries

    MedlinePLUS

    ... ACFAS | Información en Español Advanced Search Home » Foot & Ankle Conditions » Peroneal Tendon Injuries Text Size Print Bookmark ... foot run side-by-side behind the outer ankle bone. One peroneal tendon attaches to the outer ...

  1. Arthroscopic Changes of the Biceps Pulley in Rotator Cuff Tear and Its Clinical Significance in Relation to Treatment

    PubMed Central

    Choi, Chang Hyuk; Kim, Se Sik; Lee, Ju Hwan

    2015-01-01

    Background In the case of rotator cuff tears, the biceps pulley can be stressed by the unstable biceps tendon, and this can subsequently affect the stability of the subscapularis tendon. Therefore, it is important to distinguish between normal variations and lesions of the biceps pulley that affect anterosuperior lesions in cases of rotator cuff tears. Methods From January 2002 through November 2010, we observed biceps pulley and associated anterosuperior lesions in 589 of 634 cases (93%) of arthroscopic rotator cuff repair, including 72 cases (12.2%) of small tears, 219 cases (37.2%) of medium tears, 134 cases (22.8%) of large tears, and 164 cases (27.8%) of massive tears. We classified normal stretched biceps pulleys as type I, stretched biceps pulleys with mild changes as type II, those with a partial tear as type III, and torn pulleys as type IV. Results We were able to classify 589 cases of biceps pulleys as type I, II, III, or IV associated lesions in rotator cuff tears. Type I was seen in 91 cases (15.4%), type II in 216 cases (36.7%), type III in 157 cases (26.7%), and type IV in 101 cases (17.1%); unidentified cases numbered 24 (4.1%). Nearly three-quarters, 73.3%, of the cases (432/589) had associated anterosuperior lesions, and combined treatment for the associated lesions was administered in 29.2% (172/589) of cases. Conclusions Biceps pulley lesions with more than partial tears were identified in 48% of rotator cuff tear cases. The incidence and severity of pulley lesions were related to the rotator cuff tear size, the status of the long head of the biceps tendon and subscapularis tendon lesion, and the treatment methods. PMID:26330960

  2. A comparison of different two-dimensional approaches for the determination of the patellar tendon moment arm length.

    PubMed

    Tsaopoulos, Dimitrios E; Baltzopoulos, Vasilios; Richards, Paula J; Maganaris, Constantinos N

    2009-03-01

    The purpose of this study was to estimate and compare the moment arm length of the patellar tendon (d) during passive knee extension using three different reference landmarks; instant centre of rotation (ICR), tibiofemoral contact point (TFCP) and geometrical centre of the posterior femoral condyles (GCFC). Measurements were taken on the right leg on seven healthy males during passive knee rotation performed by the motor of a Cybex Norm isokinetic dynamometer. Moment arms lengths were obtained by analysing lateral X-ray images recorded using a GE FlexiView 8800 C-arm videofluoroscopy system. The d-knee joint angle relations with respect to GCFC and ICR were similar, with decreasing values from full knee extension (~5.8 cm for d (GCFC) and ~5.9 cm for d (ICR)) to 90 degrees of knee flexion (~4.8 cm for both d (GCFC) and d (ICR)). However, the d (TFCP)-knee joint angle relation had an ascending-descending shape, with the highest d (TFCP) value (~5 cm) at 60 degrees of knee flexion. There was no significant difference between the GCFC and ICR methods at any knee joint angle. In contrast, there were significant differences (P < 0.01) between d (ICR) and d (TFCP) at 0 degrees , 15 degrees , 30 degrees and 45 degrees of knee flexion and between d (GCFC) and d (TFCP) at 0 degrees , 15 degrees and 30 degrees of knee flexion (P < 0.01). This study shows that when using different knee joint rotation centre definitions, there are significant differences in the estimates of the patellar tendon moment arm length, especially in more extended knee joint positions. These differences can have serious implications for joint modelling and loading applications. PMID:19125279

  3. The Use of an Intra-Articular Depth Guide in the Measurement of Partial Thickness Rotator Cuff Tears

    PubMed Central

    Carroll, Michael J.; More, Kristie D.; Sohmer, Stephen; Nelson, Atiba A.; Sciore, Paul; Boorman, Richard; Hollinshead, Robert; Lo, Ian K. Y.

    2013-01-01

    Purpose. The purpose of this study was to compare the accuracy of the conventional method for determining the percentage of partial thickness rotator cuff tears to a method using an intra-articular depth guide. The clinical utility of the intra-articular depth guide was also examined. Methods. Partial rotator cuff tears were created in cadaveric shoulders. Exposed footprint, total tendon thickness, and percentage of tendon thickness torn were determined using both techniques. The results from the conventional and intra-articular depth guide methods were correlated with the true anatomic measurements. Thirty-two patients were evaluated in the clinical study. Results. Estimates of total tendon thickness (r = 0.41, P = 0.31) or percentage of thickness tears (r = 0.67, P = 0.07) using the conventional method did not correlate well with true tendon thickness. Using the intra-articular depth guide, estimates of exposed footprint (r = 0.92, P = 0.001), total tendon thickness (r = 0.96, P = 0.0001), and percentage of tendon thickness torn (r = 0.88, P = 0.004) correlated with true anatomic measurements. Seven of 32 patients had their treatment plan altered based on the measurements made by the intra-articular depth guide. Conclusions. The intra-articular depth guide appeared to better correlate with true anatomic measurements. It may be useful during the evaluation and development of treatment plans for partial thickness articular surface rotator cuff tears. PMID:23533789

  4. Tendon functional extracellular matrix.

    PubMed

    Screen, Hazel R C; Berk, David E; Kadler, Karl E; Ramirez, Francesco; Young, Marian F

    2015-06-01

    This article is one of a series, summarizing views expressed at the Orthopaedic Research Society New Frontiers in Tendon Research Conference. This particular article reviews the three workshops held under the "Functional Extracellular Matrix" stream. The workshops focused on the roles of the tendon extracellular matrix, such as performing the mechanical functions of tendon, creating the local cell environment, and providing cellular cues. Tendon is a complex network of matrix and cells, and its biological functions are influenced by widely varying extrinsic and intrinsic factors such as age, nutrition, exercise levels, and biomechanics. Consequently, tendon adapts dynamically during development, aging, and injury. The workshop discussions identified research directions associated with understanding cell-matrix interactions to be of prime importance for developing novel strategies to target tendon healing or repair. PMID:25640030

  5. Biomimetic scaffold design for functional and integrative tendon repair.

    PubMed

    Zhang, Xinzhi; Bogdanowicz, Danielle; Erisken, Cevat; Lee, Nancy M; Lu, Helen H

    2012-02-01

    Rotator cuff tears represent the most common shoulder injuries in the United States. The debilitating effect of this degenerative condition coupled with the high incidence of failure associated with existing graft choices underscores the clinical need for alternative grafting solutions. The 2 critical design criteria for the ideal tendon graft would require the graft to not only exhibit physiologically relevant mechanical properties but also be able to facilitate functional graft integration by promoting the regeneration of the native tendon-to-bone interface. Centered on these design goals, this review will highlight current approaches to functional and integrative tendon repair. In particular, the application of biomimetic design principles through the use of nanofiber- and nanocomposite-based scaffolds for tendon tissue engineering will be discussed. This review will begin with nanofiber-based approaches to functional tendon repair, followed by a section highlighting the exciting research on tendon-to-bone interface regeneration, with an emphasis on implementation of strategic biomimicry in nanofiber scaffold design and the concomitant formation of graded multi-tissue systems for integrative soft-tissue repair. This review will conclude with a summary and discussion of future directions. PMID:22244070

  6. Bipolar Posterior Deltoid Transfer for Massive Rotator Cuff Tears: A Report on 2 Patients

    PubMed Central

    2015-01-01

    Summary: A transfer of the posterior deltoid innervated by the posterior branch of the axillary nerve and vascularized by the posterior circumflex humeral artery is described for irreparable tears of the supra- and infraspinatus muscle tendons. Functionally useful abduction and flexion were restored in 2 patients. PMID:26090280

  7. Patellar tendon reconstruction with semitendinosus-gracilis autograft.

    PubMed

    Harris, Joshua D; Fazalare, Joseph J; Phieffer, Laura S; Flanigan, David C

    2013-12-01

    We present a case of a 24-year-old, otherwise healthy, man who sustained a right knee injury after a fall. A small, comminuted inferior pole patella fracture with medial and lateral retinacular tears was encountered that required a small, nonarticular partial patellectomy and patellar tendon repair. An uneventful postoperative course was complicated by a fall onto a flexed knee and rerupture of the patellar tendon at 3 months following surgery. Intraoperatively, a significant tissue void was seen in the area of the prior repair. The patellar tendon was reconstructed with semitendinosus and gracilis autograft. At 1 year follow-up, the patient had regained a normal gait, had no pain, and had full range-of-motion without extensor lag. PMID:23288729

  8. Fatigue loading of tendon

    PubMed Central

    Shepherd, Jennifer H; Screen, Hazel R C

    2013-01-01

    Tendon injuries, often called tendinopathies, are debilitating and painful conditions, generally considered to develop as a result of tendon overuse. The aetiology of tendinopathy remains poorly understood, and whilst tendon biopsies have provided some information concerning tendon appearance in late-stage disease, there is still little information concerning the mechanical and cellular events associated with disease initiation and progression. Investigating this in situ is challenging, and numerous models have been developed to investigate how overuse may generate tendon fatigue damage and how this may relate to tendinopathy conditions. This article aims to review these models and our current understanding of tendon fatigue damage. We review the strengths and limitations of different methodologies for characterizing tendon fatigue, considering in vitro methods that adopt both viable and non-viable samples, as well as the range of different in vivo approaches. By comparing data across model systems, we review the current understanding of fatigue damage development. Additionally, we compare these findings with data from tendinopathic tissue biopsies to provide some insights into how these models may relate to the aetiology of tendinopathy. Fatigue-induced damage consistently highlights the same microstructural, biological and mechanical changes to the tendon across all model systems and also correlates well with the findings from tendinopathic biopsy tissue. The multiple testing routes support matrix damage as an important contributor to tendinopathic conditions, but cellular responses to fatigue appear complex and often contradictory. PMID:23837793

  9. Tendon lengthening and transfer.

    PubMed

    Fitoussi, F; Bachy, M

    2015-02-01

    Tendon lengthening and transfer are usually indicated for certain neuromuscular disorders, peripheral or central nerve injury, congenital disorder or direct traumatic or degenerative musculotendinous lesion. In musculotendinous lengthening, technique depends on muscle anatomy, degree of correction required, and the need to avoid excessive loss of force. Lengthening within the muscle or aponeurosis is stable. In the tendon, however, it may provide greater gain but is not stable and requires postoperative immobilization to avoid excessive lengthening. Tendon transfer consists in displacing a muscle's tendon insertion in order to restore function. The muscle to be transferred is chosen according to strength, architecture and course, contraction timing, intended direction, synergy and the joint moment arm to be restored. Functions to be restored have to be prioritized, and alternatives to transfer should be identified. The principles of tendon transfer require preoperative assessment of the quality of the tissue through which the transfer is to pass and of the suppleness of the joints concerned. During the procedure, transfer tension should be optimized and the neurovascular bundle should be protected. The method of fixation, whether tendon-to-bone or tendon-to-tendon suture, should be planned according to local conditions and the surgeon's experience. PMID:25572471

  10. Multilayered Electrospun Scaffolds for Tendon Tissue Engineering

    PubMed Central

    Chainani, Abby; Hippensteel, Kirk J.; Kishan, Alysha; Garrigues, N. William; Ruch, David S.; Guilak, Farshid

    2013-01-01

    Full-thickness rotator cuff tears are one of the most common causes of shoulder pain in people over the age of 65. High retear rates and poor functional outcomes are common after surgical repair, and currently available extracellular matrix scaffold patches have limited abilities to enhance new tendon formation. In this regard, tissue-engineered scaffolds may provide a means to improve repair of rotator cuff tears. Electrospinning provides a versatile method for creating nanofibrous scaffolds with controlled architectures, but several challenges remain in its application to tissue engineering, such as cell infiltration through the full thickness of the scaffold as well as control of cell growth and differentiation. Previous studies have shown that ligament-derived extracellular matrix may enhance differentiation toward a tendon or ligament phenotype by human adipose stem cells (hASCs). In this study, we investigated the use of tendon-derived extracellular matrix (TDM)-coated electrospun multilayered scaffolds compared to fibronectin (FN) or phosphate-buffered saline (PBS) coating for use in rotator cuff tendon tissue engineering. Multilayered poly(?-caprolactone) scaffolds were prepared by sequentially collecting electrospun layers onto the surface of a grounded saline solution into a single scaffold. Scaffolds were then coated with TDM, FN, or PBS and seeded with hASCs. Scaffolds were maintained without exogenous growth factors for 28 days in culture and evaluated for protein content (by immunofluorescence and biochemical assay), markers of tendon differentiation, and tensile mechanical properties. The collagen content was greatest by day 28 in TDM-scaffolds. Gene expression of type I collagen, decorin, and tenascin C increased over time, with no effect of scaffold coating. Sulfated glycosaminoglycan and dsDNA contents increased over time in culture, but there was no effect of scaffold coating. The Young's modulus did not change over time, but yield strain increased with time in culture. Histology demonstrated cell infiltration through the full thickness of all scaffolds and immunofluorescence demonstrated greater expression of type I, but not type III collagen through the full thickness of the scaffold in TDM-scaffolds compared to other treatment groups. Together, these data suggest that nonaligned multilayered electrospun scaffolds permit tenogenic differentiation by hASCs and that TDM may promote some aspects of this differentiation. PMID:23808760

  11. Effect of mechanical stimulation on bone marrow stromal cell-seeded tendon slice constructs: a potential engineered tendon patch for rotator cuff repair.

    PubMed

    Qin, Ting-Wu; Sun, Yu-Long; Thoreson, Andrew R; Steinmann, Scott P; Amadio, Peter C; An, Kai-Nan; Zhao, Chunfeng

    2015-05-01

    Cell-based tissue engineered tendons have potential to improve clinical outcomes following rotator cuff repair, especially in large or massive rotator cuff tears, which pose a great clinical challenge. The aim of this study was to develop a method of constructing a functional engineered tendon patch for rotator cuff repair with cyclic mechanical stimulation. Decellularized tendon slices (DTSs) were seeded with BMSCs and subjected to cyclic stretching for 1, 3, or 7 days. The mechanical properties, morphologic characteristics and tendon-related gene expression of the constructs were investigated. Viable BMSCs were observed on the DTS after 7 days. BMSCs penetrated into the DTSs and formed dense cell sheets after 7 days of mechanical stretching. Gene expression of type I collagen, decorin, and tenomodulin significantly increased in cyclically stretched BMSC-DTS constructs compared with the unstrained control group (P < 0.05). The ultimate tensile strength and stiffness of the cyclically stretched tendon constructs were similar to the unstrained control group (P > 0.05). In conclusion, mechanical stimulation of BMSC-DTS constructs upregulated expression of tendon-related proteins, promoted cell tenogenic differentiation, facilitated cell infiltration and formation of cell sheets, and retained mechanical properties. The patch could be used as a graft to enhance the surgical repair of rotator cuff tears. PMID:25770996

  12. The Atypical Homeodomain Transcription Factor Mohawk Controls Tendon Morphogenesis?

    PubMed Central

    Liu, Wenjin; Watson, Spencer S.; Lan, Yu; Keene, Douglas R.; Ovitt, Catherine E.; Liu, Han; Schweitzer, Ronen; Jiang, Rulang

    2010-01-01

    The Mohawk homeobox (Mkx) gene encodes a new atypical homeodomain-containing protein with transcriptional repressor activity. Mkx mRNA exhibited dynamic expression patterns during development of the palate, somite, kidney, and testis, suggesting that it may be an important regulator of multiple developmental processes. To investigate the roles of Mkx in organogenesis, we generated mice carrying a null mutation in this gene. Mkx?/? mice survive postnatally and exhibit a unique wavy-tail phenotype. Close examination revealed that the mutant mice had smaller tendons than wild-type littermates and that the rapid postnatal growth of collagen fibrils in tendons was disrupted in Mkx?/? mice. Defects in tendon development were detected in the mutant mouse embryos as early as embryonic day 16.5 (E16.5). Although collagen fibril assembly initially appeared normal, the tendons of Mkx?/? embryos expressed significantly reduced amounts of collagen I, fibromodulin, and tenomodulin in comparison with control littermates. We found that Mkx mRNA was strongly expressed in differentiating tendon cells during embryogenesis and in the tendon sheath cells in postnatal stages. In addition to defects in tendon collagen fibrillogenesis, Mkx?/? mutant mice exhibited abnormal tendon sheaths. These results identify Mkx as an important regulator of tendon development. PMID:20696843

  13. A between sex comparison of anterior-posterior knee laxity after anterior cruciate ligament reconstruction with patellar tendon or hamstrings autograft: a systematic review.

    PubMed

    Paterno, Mark V; Weed, Ashley M; Hewett, Timothy E

    2012-02-01

    Anterior-posterior (AP) knee laxity after anterior cruciate ligament (ACL) reconstruction may differ between sexes for different graft types. Females may experience an increase in AP knee laxity following an ACL reconstruction with a hamstrings graft, which is not seen in males with a hamstrings graft or in males or females with a bone-patellar tendon-bone (BTB) graft. The hypothesis of this review is sex differences in AP knee laxity and this will be identified in patients who undergo an ACL reconstruction with a hamstrings graft, while no sex differences will be observed in patients who have an ACL reconstruction with a BTB graft. A systematic search was performed in PubMed, CINAHL and SPORTDiscus. Inclusion criteria were articles published in the English language that studied human subjects who underwent an ACL reconstruction with a BTB or hamstrings autograft, and the presence of a sex comparison on outcome measures including side-to-side difference in AP knee laxity. Methodological quality was assessed using a Modified Coleman Methodology Score. Eleven cohort studies met the inclusion criteria. Six investigated sex differences in both hamstrings and BTB grafts. Three only investigated BTB grafts and two only investigated hamstrings grafts. These studies consistently reported increases in AP knee laxity in females after an ACL reconstruction with a hamstrings graft that was not observed in the other cohorts. This systematic review indicates that female patients have greater AP knee laxity following an ACL reconstruction with a hamstrings autograft compared with males with a similar procedure, and both females and males following an ACL reconstruction with a BTB autograft. These results are derived from lower level evidence, as no randomized control trials have attempted to answer this question. Future studies need to rigorously address this clinical question to confirm the results currently in the literature. PMID:22260514

  14. Tendon gradient mineralization for tendon to bone interface integration.

    PubMed

    Qu, Jin; Thoreson, Andrew R; Chen, Qingshan; An, Kai-Nan; Amadio, Peter C; Zhao, Chunfeng

    2013-11-01

    Tendon-to-bone integration is a great challenge for tendon or ligament reconstruction regardless of use of autograft or allograft tendons. We mineralized the tendon, thus transforming the tendon-to-bone into a "bone-to-bone" interface for healing. Sixty dog flexor digitorum profundus (FDP) tendons were divided randomly into five groups: (1) normal FDP tendon, (2) CaP (non-extraction and mineralization without fetuin), (3) CaPEXT (Extraction by Na2 HPO4 and mineralization without fetuin), (4) CaPFetuin (non-extraction and mineralization with fetuin), and (5) CaPEXTFetuin (extraction and mineralization with fetuin). The calcium and phosphate content significantly increased in tendons treated with combination of extraction and fetuin compared to the other treatments. Histology also revealed a dense mineral deposition throughout the tendon outer layers and penetrated into the tendon to a depth of 200 µm in a graded manner. Compressive moduli were significantly lower in the four mineralized groups compared with normal control group. No significant differences in maximum failure strength or stiffness were found in the suture pull-out test among all groups. Mineralization of tendon alters the interface from tendon to bone into mineralized tendon to bone, which may facilitate tendon-to-bone junction healing following tendon or ligament reconstruction. PMID:23939935

  15. Tendon injuries of the hand

    PubMed Central

    Schöffl, Volker; Heid, Andreas; Küpper, Thomas

    2012-01-01

    Tendon injuries are the second most common injuries of the hand and therefore an important topic in trauma and orthopedic patients. Most injuries are open injuries to the flexor or extensor tendons, but less frequent injuries, e.g., damage to the functional system tendon sheath and pulley or dull avulsions, also need to be considered. After clinical examination, ultrasound and magnetic resonance imaging have proved to be important diagnostic tools. Tendon injuries mostly require surgical repair, dull avulsions of the distal phalanges extensor tendon can receive conservative therapy. Injuries of the flexor tendon sheath or single pulley injuries are treated conservatively and multiple pulley injuries receive surgical repair. In the postoperative course of flexor tendon injuries, the principle of early passive movement is important to trigger an “intrinsic” tendon healing to guarantee a good outcome. Many substances were evaluated to see if they improved tendon healing; however, little evidence was found. Nevertheless, hyaluronic acid may improve intrinsic tendon healing. PMID:22720265

  16. Reconstruction of chronic tearing of the distal triceps using the double-row configuration: technical note?

    PubMed Central

    Paniago, Alexandre Firmino; Storti, Thiago Medeiros; Faria, Rafael Salomon Silva; Morais, Dennys Carlos Aragão de; Souza, Murillo Pablo de

    2015-01-01

    Tearing of the distal triceps is uncommon and may be difficult to diagnose, especially in situations of partial tearing. Imaging methods such as ultrasonography and magnetic resonance imaging should be used to confirm the diagnosis and define the extent of the injury. The preferred treatment for complete tearing of the triceps is surgical, unlike in cases of partial tearing, in which the treatment depends on factors such as pain, functional deficit and the patient's expectations. Here, we describe the case of a patient with partial tearing of the distal triceps after falling to the ground, which was not diagnosed at the time of first attendance and evolved with pain and great functional loss. The surgical procedure was performed nine months after the injury, with reconstruction of the triceps by means of reinforcement using the tendon of the ipsilateral semitendinosus and fixation in the olecranon using the double-row configuration. The patient remained immobilized using a sling for one week and then gains in passive range of motion (ROM) were introduced. Three weeks later, the patient was released for gains in active ROM. Muscle strengthening was started after 12 weeks. Six weeks after the surgical procedure, the patient was free from pain and presented complete ROM, grade V elbow extension force and hypertrophy of the triceps. The technique described here was shown to be useful for treating tears of the tendon of the distal triceps. PMID:26535208

  17. Bilateral Achilles tendon enlargement.

    PubMed

    Huang, Lu; Miao, Xu-dong; Yang, Di-sheng; Tao, Hui-min

    2011-12-01

    Cerebrotendinous xanthomatosis is a rare, autosomal-recessive, lipid-storage disease with accumulation of cholestanol in most tissues, particularly within the Achilles tendons. It has been characterized both clinically and biochemically, and recently from the molecular biological aspect as well. Juvenile cataract, childhood diarrhea, mental retardation, cerebellar ataxia, and tendon xanthomas are the most prominent features of this disease. Bilateral symmetrical firm masses of Achilles tendons may be the first symptom the patient recognizes because it can jeopardize his or her ability to walk. However, the treatment strategies for tendon tumors vary. In a recent case, we diagnosed the disease properly, according to the clinical manifestations and the radiological and laboratory examinations. The genetic mutation was characterized by analyzing sterol 27-hydroxylase from the patient's family (located on nucleotide 599) and led to a nonsense mutation. It is a unique type of mutation that has never been reported to our knowledge. Tendon lesions are characterized by the loss of muscle fibers and accumulation of lipid products. To help the patient regain the strength of the Achilles tendon and walking abilities, a large area of tendon tumor was excised, followed by reconstruction with a tibialis posterior allograft, which is the second strongest tendon in the foot and ankle. Although the use of this type of graft is uncommon, the final result was satisfactory. At the 10-month follow-up examination, the patient could walk easily without pain. This case report suggests that the surgical procedure will provide an alternative for the repair of large-area degenerative Achilles tendons. PMID:22146219

  18. Structural Characteristics Are Not Associated With Pain and Function in Rotator Cuff Tears

    PubMed Central

    Curry, Emily J.; Matzkin, Elizabeth E.; Dong, Yan; Higgins, Laurence D.; Katz, Jeffrey N.; Jain, Nitin B.

    2015-01-01

    Background: Structural characteristics of rotator cuff tears are used in surgical decision making. However, data on the association of tear size with patient-reported pain and function are sparse. Purpose: To assess the association of tear size, fatty infiltration, and muscle atrophy with shoulder pain/function in patients with cuff tears undergoing operative and nonoperative treatment. Study Design: Cross-sectional study; Level of evidence, 3. Methods: A total of 67 patients with rotator cuff tears were recruited for this longitudinal cohort study. Patients were determined to have a cuff tear using clinical assessment and blinded magnetic resonance imaging review. The Shoulder Pain and Disability Index (SPADI) was used as a measure of shoulder pain and function. Results: Tear size and thickness were not significantly associated with pain (SPADI pain score, 60.6 [95% CI, 49.8-71.5] for partial-thickness tear; 56.8 [95% CI, 42.8-70.7] for <2 cm full-thickness tear; 60.4 [95% CI, 51.7-69.0] for ?2 cm full-thickness tear). Tear size and thickness were not associated with function (SPADI disability score, 42.7 [95% CI, 29.8-55.6] for partial-thickness tear; 37.6 [95% CI, 23.9-51.4] for <2 cm full-thickness tear; 45.1 [95% CI, 35.4-54.8] for ?2 cm full-thickness tear). Fatty infiltration, muscle atrophy, and tendon retraction were also not significantly associated with SPADI pain and disability scores. A Mental Health Index score of <68 as well as age ?60 years were significantly associated with a higher SPADI pain score. Female sex, increased number of comorbidities, Mental Health Index score of <68, and age <60 years were significantly associated with a higher SPADI disability score. Conclusion: In patients with rotator cuff tears undergoing operative and nonoperative treatment, pain and functional status were not associated with tear size and thickness, fatty infiltration, and muscle atrophy. Conversely, factors unrelated to cuff anatomy such as mental health, comorbidities, age, and sex were associated with pain/function. These findings have clinical implications during surgical decision making and suggest that pain and functional disability in patients with rotator cuff tears is multifactorial and should not solely be attributed to structural characteristics. PMID:26675985

  19. Common Disorders of the Achilles Tendon

    MedlinePLUS

    ... Text Size Print Bookmark Common Disorders of the Achilles Tendon What Is the Achilles Tendon? A tendon is a band of tissue ... helping to raise the heel off the ground. Achilles Tendonitis and Achilles Tendonosis Two common disorders that ...

  20. Tears of Wine

    ERIC Educational Resources Information Center

    Gugliotti, Marcos

    2004-01-01

    The unique occurrence of the upward motion of a thin film of wine, and its formation into drops inside the wall of a wine glass is explained. Evaporation of alcohol generates a surface tension gradient, moving the film of wine upwards on the internal sides of a wine glass, where it collects and forms into drops or tears.

  1. Jumper's Knee (Patellar Tendonitis)

    MedlinePLUS

    ... a particular area of the body). Constant jumping, landing, and changing direction can cause strains, tears, and ... strength to jump, and stabilize the leg for landing. Continue About Jumper's Knee When the knee is ...

  2. Fibrocartilage in tendons and ligaments — an adaptation to compressive load

    PubMed Central

    BENJAMIN, M.; RALPHS, J. R.

    1998-01-01

    Where tendons and ligaments are subject to compression, they are frequently fibrocartilaginous. This occurs at 2 principal sites: where tendons (and sometimes ligaments) wrap around bony or fibrous pulleys, and in the region where they attach to bone, i.e. at their entheses. Wrap-around tendons are most characteristic of the limbs and are commonly wider at their point of bony contact so that the pressure is reduced. The most fibrocartilaginous tendons are heavily loaded and permanently bent around their pulleys. There is often pronounced interweaving of collagen fibres that prevents the tendons from splaying apart under compression. The fibrocartilage can be located within fascicles, or in endo- or epitenon (where it may protect blood vessels from compression or allow fascicles to slide). Fibrocartilage cells are commonly packed with intermediate filaments which could be involved in transducing mechanical load. The ECM often contains aggrecan which allows the tendon to imbibe water and withstand compression. Type II collagen may also be present, particularly in tendons that are heavily loaded. Fibrocartilage is a dynamic tissue that disappears when the tendons are rerouted surgically and can be maintained in vitro when discs of tendon are compressed. Finite element analyses provide a good correlation between its distribution and levels of compressive stress, but at some locations fibrocartilage is a sign of pathology. Enthesis fibrocartilage is most typical of tendons or ligaments that attach to the epiphyses of long bones where it may also be accompanied by sesamoid and periosteal fibrocartilages. It is characteristic of sites where the angle of attachment changes throughout the range of joint movement and it reduces wear and tear by dissipating stress concentration at the bony interface. There is a good correlation between the distribution of fibrocartilage within an enthesis and the levels of compressive stress. The complex interlocking between calcified fibrocartilage and bone contributes to the mechanical strength of the enthesis and cartilage-like molecules (e.g. aggrecan and type II collagen) in the ECM contribute to its ability to withstand compression. Pathological changes are common and are known as enthesopathies. PMID:10029181

  3. [Achilles tendon rupture].

    PubMed

    Thermann, H; Hüfner, T; Tscherne, H

    2000-03-01

    The treatment of acute of Achilles tendon rupture experienced a dynamic development in the last ten years. Decisive for this development was the application of MRI and above all the ultrasonography in the diagnostics of the pathological changes and injuries of tendons. The question of rupture morphology as well as different courses of healing could be now evaluated objectively. These advances led consequently to new modalities in treatment concepts and rehabilitation protocols. The decisive input for improvements of the outcome results and particularly the shortening of the rehabilitation period came with introduction of the early functional treatment in contrast to immobilizing plaster treatment. In a prospective randomized study (1987-1989) at the Trauma Dept. of the Hannover Medical School could show no statistical differences comparing functional non-operative with functional operative therapy with a special therapy boot (Variostabil/Adidas). The crucial criteria for therapy selection results from the sonographically measured position of the tendon stumps in plantar flexion (20 degrees). With complete adaptation of the tendons' ends surgical treatment does not achieve better results than non-operative functional treatment in term of tendon healing and functional outcome. Regarding the current therapeutic standards each method has is advantages and disadvantages. Both, the operative and non-operative functional treatment enable a stable tendon healing with a low risk of re-rupture (1-2%). Meanwhile there is consensus for early functional after-treatment of the operated Achilles' tendons. There seems to be a trend towards non-operative functional treatment in cases of adequate sonographical findings, or to minimal invasive surgical techniques. PMID:10798233

  4. Evaluation of greater petrosal nerve function in patients with acute peripheral facial paralysis: comparison of soft palate electrogustometry and Schirmer's tear test.

    PubMed

    Kawamoto, Hidetoshi; Ikeda, Minoru

    2002-01-01

    We tested sensory and secretomotor function of the greater petrosal nerve (GPN) by means of electrogustometry (EGM) of the soft palate and Schirmer's tear test in 115 patients (59 males, 56 females) with acute peripheral facial paralysis. Facial paralysis was caused by Bell's palsy in 78 cases, Ramsay Hunt syndrome in 27 cases and zoster sine herpetic lesions in 10. All patients had dysfunction of the stapedial nerve. An electrogustometer was used to test taste (GPN sensory function), and elevation of the threshold by > 6 dB on the affected side was considered abnormal. Schirmer's test was used to evaluate lacrimal (GPN secretomotor) function, which was considered abnormal when tear secretion on the affected side was < 50% of secretion on the non-affected side. Of the 78 patients with Bell's palsy, 28.2% had altered taste on the soft palate (sensory dysfunction) and 10.3% had lacrimal dysfunction, indicating that EGM of the soft palate is more sensitive than Schirmer's test for identifying dysfunction of the GPN in patients with facial paralysis due to Bell's palsy. Of the total of 115 patients, 32 (28%) had taste dysfunction and 9 (28.1%) of these 32 patients also had lacrimal dysfunction. This finding indicates that facial paralysis has different effects on the sensory and secretory nerve fibers of the GPN. The results of Schirmer's test were more closely related to the severity of, and prognosis for, facial paralysis than the results of EGM. PMID:12132607

  5. Tendon Driven Finger Actuation System

    NASA Technical Reports Server (NTRS)

    Ihrke, Chris A. (Inventor); Reich, David M. (Inventor); Bridgwater, Lyndon (Inventor); Linn, Douglas Martin (Inventor); Askew, Scott R. (Inventor); Diftler, Myron A. (Inventor); Platt, Robert (Inventor); Hargrave, Brian (Inventor); Valvo, Michael C. (Inventor); Abdallah, Muhammad E. (Inventor); Permenter, Frank Noble (Inventor); Mehling, Joshua S. (Inventor)

    2013-01-01

    A humanoid robot includes a robotic hand having at least one finger. An actuation system for the robotic finger includes an actuator assembly which is supported by the robot and is spaced apart from the finger. A tendon extends from the actuator assembly to the at least one finger and ends in a tendon terminator. The actuator assembly is operable to actuate the tendon to move the tendon terminator and, thus, the finger.

  6. Comparison of the effect of intra-tendon applications of recombinant human platelet-derived growth factor-BB, platelet-rich plasma, steroids in a rat achilles tendon collagenase model.

    PubMed

    Solchaga, Luis A; Bendele, Alison; Shah, Vivek; Snel, Leo B; Kestler, Hans K; Dines, Joshua S; Hee, Christopher K

    2014-01-01

    This study compared the effect of intra-tendon (IT) delivery of recombinant human platelet-derived growth factor-BB (rhPDGF-BB), platelet-rich plasma (PRP) and corticosteroids in a rat tendinopathy model. Seven days after collagenase induction of tendinopathy, a 30-µl IT injection was administered. Treatments included: saline; 3 µg rhPDGF-BB; 10 µg rhPDGF-BB; PRP; and 300 µg triamcinolone acetonide (TCA). Outcomes were assessed 7 and 21 days after treatment. All groups exhibited good to excellent repair. Relative to saline, cell proliferation increased 65% in the 10 µg rhPDGF-BB group and decreased 74% in the TCA group; inflammation decreased 65% in the TCA group. At 7 days, maximum load-to-failure was increased in the 3 µg rhPDGF-BB group relative to saline, PRP, and TCA (p < 0.025). On day 21, maximum load-to-rupture was increased in the 10 µg rhPDGF-BB group relative to saline, PRP, and TCA (p < 0.035) and in the 3 µg rhPDGF-BB group compared to saline and TCA (p < 0.027). Stiffness in the 10 µg rhPDGF-BB group was increased compared to saline, PRP, and TCA (p < 0.038). Histology demonstrated similar repair in all groups. PRP and TCA did not improve mechanical properties compared to saline. Injections of rhPDGF-BB increased maximum load-to-failure (3 and 10 µg) and stiffness (10 µg) relative to controls and commonly used treatments. © 2013 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 32:145-150, 2014. PMID:24018586

  7. The basic science behind biologic augmentation of tendon-bone healing: a scientific review.

    PubMed

    Weeks, Kenneth D; Dines, Joshua S; Rodeo, Scott A; Bedi, Asheesh

    2014-01-01

    Rotator cuff tears are common musculoskeletal injuries that often require surgical repair. Despite advances in surgical techniques, including progression from a single row of anchors to double-row constructs, recurrent tearing or failure to heal still complicates 10% to 94% of repairs. The surgical treatment of rotator cuff tears is aimed at providing the best mechanical environment for tendon healing. Despite appropriate surgical management and a normal healing response, the resultant tendon healing does not regenerate the tendon-bone architecture initially formed during prenatal development. Instead, a mechanically weaker, fibrovascular scar is formed, leading to suboptimal healing rates and/or higher retear rates. Biologic augmentation strategies aim to improve healing rates by introducing higher concentrations of growth factors and cytokines, mesenchymal stem cells, and enzymatic antagonists to the repair site in the hope of directing a more sophisticated healing response. Biologic augmentation and tissue engineering to improve tendon-to-bone healing remains promising but will require more study before its clinical application is realized. PMID:24720329

  8. Neuronal regulation of tendon homoeostasis

    PubMed Central

    Ackermann, Paul W

    2013-01-01

    The regulation of tendon homoeostasis, including adaptation to loading, is still not fully understood. Accumulating data, however, demonstrates that in addition to afferent (sensory) functions, the nervous system, via efferent pathways which are associated with through specific neuronal mediators plays an active role in regulating pain, inflammation and tendon homeostasis. This neuronal regulation of intact-, healing- and tendinopathic tendons has been shown to be mediated by three major groups of molecules including opioid, autonomic and excitatory glutamatergic neuroregulators. In intact healthy tendons the neuromediators are found in the surrounding structures: paratenon, endotenon and epitenon, whereas the proper tendon itself is practically devoid of neurovascular supply. This neuroanatomy reflects that normal tendon homoeostasis is regulated from the tendon surroundings. After injury and during tendon repair, however, there is extensive nerve ingrowth into the tendon proper, followed by a time-dependent emergence of sensory, autonomic and glutamatergic mediators, which amplify and fine-tune inflammation and regulate tendon regeneration. In tendinopathic condition, excessive and protracted presence of sensory and glutamatergic neuromediators has been identified, suggesting involvement in inflammatory, nociceptive and hypertrophic (degenerative) tissue responses. Under experimental and clinical conditions of impaired (e.g. diabetes) as well as excessive (e.g. tendinopathy) neuromediator release, dysfunctional tendon homoeostasis develops resulting in chronic pain and gradual degeneration. Thus there is a prospect that in the future pharmacotherapy and tissue engineering approaches targeting neuronal mediators and their receptors may prove to be effective therapies for painful, degenerative and traumatic tendon disorders. PMID:23718724

  9. Tibialis Anterior Tendon Transfer.

    PubMed

    Mulhern, Jennifer L; Protzman, Nicole M; Brigido, Stephen A

    2016-01-01

    Tendon transfer procedures are used commonly for the correction of soft tissue imbalances and instabilities. The complete transfer and the split transfer of the tibialis anterior tendon are well-accepted methods for the treatment of idiopathic equinovarus deformity in children and adults. Throughout the literature, complete and split transfer have been shown to yield significant improvements in ankle and foot range of motion and muscle function. At present, there is insufficient evidence to recommend one procedure over the other, although the split procedure has been advocated for consistently achieving inversion to eversion muscle balance without overcorrection. PMID:26590723

  10. Posterior Tibial Tendon Transfer.

    PubMed

    Shane, Amber M; Reeves, Christopher L; Cameron, Jordan D; Vazales, Ryan

    2016-01-01

    When performed correctly with the right patient population, a tibialis posterior muscle/tendon transfer is an effective procedure. Many different methods have been established for fixating the tendon, each of which has its' own indications. Passing through the interosseous membrane is the preferred and recommended method and should be used unless this is not possible. Good surgical planning based on patient needs and expectations, along with excellent postoperative care including early range of motion and physical therapy minimizes risk of complications and allows for the optimal outcome to be achieved. PMID:26590722

  11. Jones Tendon Transfer.

    PubMed

    Derner, Richard; Holmes, Jeffrey

    2016-01-01

    Hallux malleus is a deformity of the great toe. There is a dorsiflexion contracture at the metatarsophalangeal joint and plantar flexion of the interphalangeal joint. The deformity is commonly attributed to muscular imbalances of the various structures acting on the great toe. Jones tendon transfer is a procedure used to remove the deforming force to the clawed hallux. It is most often performed in conjunction with a hallux interphalangeal joint fusion. Typically there is a neurologic component causing a deformity to the entire foot, necessitating adjunct procedures. The Jones tendon transfer has shown to have reproducible results. PMID:26590724

  12. Open Achilles tendon lacerations.

    PubMed

    Said, M Nader; Al Ateeq Al Dosari, Mohamed; Al Subaii, Nasser; Kawas, Alaa; Al Mas, Ali; Al Ser, Yaser; Abuodeh, Yousef; Shakil, Malik; Habash, Ali; Mukhter, Khalid

    2015-04-01

    In contrast to closed Achilles tendon ruptures, open injuries are rarely reported in the literature. This paper provides information about open Achilles tendon wounds that are eventually seen in the Middle East. The reporting unit, Hamad Medical Corporation, is one of the biggest trauma centers in the Gulf area and the major health provider in Qatar. This is a retrospective study including patients admitted and operated for open Achilles tendon injuries between January 2011 and December 2013. Two hundred and five cases of open Achilles tendon lacerations were operated in Hamad General Hospital in this period. Forty-eight cases showed partial injuries, and the remaining are complete tendons cut. In the same period, fifty-one closed ruptured Achilles tendons were operated in the same trauma unit. In the majority of cases, the open injury resulted from a slip in the floor-leveled traditional toilette seats. Local damage to the toilette seats resulted in sharp edges causing the laceration of the heel if the patient was slipping over the wet floor. This occurrence is the cause in the vast majority of the cases. Wounds were located 1-5 cm proximal to tendon insertion. Standard treatment principles were applied. This included thorough irrigation in the emergency room, intravenous antibiotics, surgical debridement and primary repair within 24 h. Patients were kept in the hospital 1-7 days for intravenous antibiotics and possible dressing changes. Postoperatively below knee slabs were applied in the majority of patients and were kept for about 4 weeks followed by gradual weight bearing and range of motion exercises. Outpatients follow up in 1-2 weeks. Further follow-up visits at around 2-, 4-, 8- and 12-week intervals until complete wound healing and satisfactory rehabilitation outcome. Sixteen cases needed a second procedure. A high incidence of Achilles tendon open injuries is reported. This seems to be related to partially damaged floor-level toilettes in the typical Middle-East lavatory. The surgical treatment resulted in excellent outcome in the vast majority of the cases. Low incidence of complications resulted despite dramatic injury pattern. PMID:25337957

  13. APPLICATION NOTE Analysis of Tear Glucose Concentration

    E-print Network

    Asher, Sanford A.

    of tear fluid. We used a 1 L micro-capillary to collect tear fluid from the tear meniscus with minimal irritation of the eye. We analyzed the 1 L volume of collected tear fluid with liquid monitoring by using tear fluid glucose as an indicator for blood glucose [4­6]. Such an ap- proach

  14. Evaluation of Global Load Sharing and Shear-lag Models to Describe Mechanical Behavior in Partially Lacerated Tendons

    E-print Network

    Lakes, Roderic

    1 Evaluation of Global Load Sharing and Shear-lag Models to Describe Mechanical Behavior The mechanical effect of a partial thickness tear or laceration of a tendon is analytically modeled under various assumptions and results are compared with previous experimental data. Among several fibril-level models

  15. Diagnosis and management of superior labral anterior posterior tears in throwing athletes.

    PubMed

    Knesek, Michael; Skendzel, Jack G; Dines, Joshua S; Altchek, David W; Allen, Answorth A; Bedi, Asheesh

    2013-02-01

    Injury to the superior glenoid labrum is increasingly recognized as a significant source of shoulder pain and dysfunction in the throwing athlete. Several theories have been proposed to explain the pathogenesis of superior labral anterior posterior (SLAP) tears. The clinical examination of the superior labrum-biceps tendon complex remains challenging because of a high association of other shoulder injuries in overhead athletes. Many physical examination findings have high sensitivity and low specificity. Advances in soft tissue imaging such as magnetic resonance arthrography allow for improved detection of labrum and biceps tendon lesions, although correlation with history and physical examination is critical to identify symptomatic lesions. Proper treatment of throwers with SLAP tears requires a thorough understanding of the altered biomechanics and the indications for nonoperative management and arthroscopic treatment of these lesions. PMID:23172004

  16. Treatment options for irreparable postero-superior cuff tears in young patients

    PubMed Central

    Galasso, Olimpio; Familiari, Filippo; Gasparini, Giorgio

    2015-01-01

    Rotator cuff tears (RCTs) occur more commonly with advanced age, with most rotator cuff abnormalities in patients less than 30 years old being painful tendinoses or partial-thickness RCTs. Irreparable postero-superior cuff tears has been reported as frequent as 7% to 10% in the general population, and the incidence of irreparable RCTs in young patients is still unknown. Several surgical procedures have been proposed for young patients with irreparable postero-superior RCTs, such as rotator cuff debridement, partial rotator cuff repair, biceps tenotomy/tenodesis, rotator cuff grafting, latissimus dorsi tendon transfer, and reverse shoulder arthroplasty. After being thoroughly investigated in open surgery, arthroscopic techniques for latissimus dorsi tendon transfer have been recently described. They have been shown to be an adequate option to open surgery for managing irreparable postero-superior RCTs refractory to conservative management. PMID:26601058

  17. Percutaneous Achilles Tendon Lengthening

    MedlinePLUS

    ... their toes. The tight Achilles tendon prevents the foot from sitting flat on the floor, and ankle motion can be limited. When this tightness cannot be treated with nonsurgical stretching or ... correct a mal-positioned foot. Patients that develop ulcers in the front part ...

  18. A Comparison of the Fixation Strengths Provided by Different Intraosseous Tendon Lengths during Anterior Cruciate Ligament Reconstruction: A Biomechanical Study in a Porcine Tibial Model

    PubMed Central

    Yang, Dong-Lyul; Cheon, Sang-Ho; Oh, Chang-Wug

    2014-01-01

    Background The purpose of this study was to determine the tibial fixation strength provided by different intraosseous soft tissue graft lengths within the tibial tunnel. Methods Porcine tibial bones and digital flexor tendons were used for testing. Bone mineral densities of proximal tibial medial condyles were measured, and two-strand tendon bundles of 8 mm diameter were used. An intraosseous graft length of 2 cm was used in group 1 (n = 10), and a graft length of 4 cm was used in group 2 (n = 10). Tunnels were 4 cm in length and 8 mm in diameter. Tibial fixation was performed using a suture tied around a screw post with a washer and an additionally inserted 7 × 20 mm bioabsorbable screw. After applying preconditioning loading of 10 cycles, 1,000 cycles between 70-220 N were applied at a frequency of 1 Hz. Graft slippage and total graft movement were recorded. Ultimate tensile strength was measured by pull-out testing at an Instron crosshead speed of 1,000 mm/min. Results No significant intergroup difference was found for total graft movement after cyclic loading (slippage in group 1, 1.2 mm and group 2, 1.2 mm, respectively, p = 0.917; and total graft movement in group 1, 3.3 mm and group 2, 2.7 mm, respectively, p = 0.199). However, mean ultimate tensile strength in group 2 was significantly higher than that in group 1 (group 1, 649.9 N; group 2, 938 N; p = 0.008). Conclusions In a porcine model, ultimate tensile strength was greater for a 4 cm long intraosseous flexor tendon in the tibial tunnel. However, no intergroup difference in graft slippage or total graft movement was observed. The results show that a 2 cm intraosseous graft length in the tibial tunnel is safe and has sufficient strength (> 450 N) for adequate rehabilitation after anterior cruciate ligament reconstruction. PMID:24900898

  19. Humeral head cysts: association with rotator cuff tears and age.

    PubMed

    Suluova, Fatih; Kanatli, Ulunay; Ozturk, Burak Yagmur; Esen, Erdinc; Bolukbasi, Selcuk

    2014-07-01

    The objective of this study was to retrospectively evaluate the prevalence of the cystic changes at rotator cuff footprint on proximal humeral tuberosities and investigate their relationship with rotator cuff tears and patient age. Magnetic resonance (MR) images of 657 patients who underwent shoulder arthroscopy for treatment of rotator cuff disorders were reviewed to localize the cystic changes at anterior (supraspinatus insertion) and posterior (infraspinatus insertion) aspects of greater tuberosity (GT) and lesser tuberosity (subscapularis insertion). Preoperative MR reports as well as cyst size and locations on MR images were correlated with arthroscopic records of rotator cuff pathology (tear type, size, location and tendon involvement) and patient age. The prevalence of cystic changes was 9.1% (60 patients) in the study population. Anterior GT cysts were found in 56% of patients and were strongly associated with full-thickness (p<.001) and articular-sided partial-thickness rotator cuff tears (p=.02). Posterior GT and lesser tuberosity cysts were found in 27 and 17% of patients, respectively, and were not significantly related to rotator cuff tears, although there was an increased trend of posterior cysts in patients with infraspinatus tears (p=.09). A significant relation was found between patient age and the cyst size (p=.01), while none of the cyst localizations were statistically related to age. Anterior GT cysts were more common in this patient group and demonstrated a strong association with rotator cuff disorders regardless of age. Posterior GT and lesser tuberosity cysts were less common and showed no association with rotator cuff pathology or patient age. PMID:23748696

  20. Tendon Reconstruction with Tissue Engineering Approach--A Review.

    PubMed

    Verdiyeva, Gunay; Koshy, Kiron; Glibbery, Natalia; Mann, Haroon; Seifalian, Alexander M

    2015-09-01

    Tendon injuries are a common and rising occurrence, associated with significant impairment to quality of life and financial burden to the healthcare system. Clinically, they represent an unresolved problem, due to poor natural tendon healing and the inability of current treatment strategies to restore the tendon to its native state. Tissue engineering offers a promising alternative, with the incorporation of scaffolds, cells and growth factors to support the complete regeneration of the tendon. The materials used in tendon engineering to date have provided significant advances in structural integrity and biological compatibility and in many cases the results obtained are superior to those observed in natural healing. However, grafts fail to reproduce the qualities of the pre-injured tendon and each has weaknesses subject to its constituent parts. Furthermore, many materials and cell types are being investigated concurrently, with seemingly little association or comparison between research results. In this review the properties of the most-investigated and effective components have been appraised in light of the surrounding literature, with research from early in-vitro experiments to clinical trials being discussed. Extensive comparisons have been made between scaffolds, cell types and growth factors used, listing strengths and weaknesses to provide a stable platform for future research. Promising future endeavours are also described in the field of nanocomposite material science, stem cell sources and growth factors, which may bypass weaknesses found in individual elements. The future of tendon engineering looks bright, with growing understanding in material technology, cell and growth factor application and encouraging recent advances bringing us ever closer to regenerating the native tendon. PMID:26485923

  1. Tear Film Lipids

    PubMed Central

    Butovich, Igor A.

    2013-01-01

    Human meibomian gland secretions (MGS, or meibum) are formed from a complex mixture of lipids of different classes such as wax esters, cholesteryl esters, (O-acyl)-?-hydroxy fatty acids (OAHFA) and their esters, acylglycerols, diacylated diols, free fatty acids, cholesterol, and a smaller amount of other polar and nonpolar lipids, whose chemical nature and the very presence in MGS have been a matter of intense debates. The purpose of this review is to discuss recent results that were obtained using different experimental techniques, estimate limitations of their usability, and discuss their biochemical, biophysical, and physiological implications. To create a lipid map of MGS and tears, the results obtained in the author’s laboratory were integrated with available information on chemical composition of MGS and tears. The most informative approaches that are available today to researchers, such as HPLC-MS, GC-MS, and proton NMR, are discussed in details. A map of the meibomian lipidome (as it is seen in reverse phase liquid chromatography/mass spectrometry experiments) is presented. Directions of future efforts in the area are outlined. PMID:23769846

  2. In vitro effects of glutamate and N-methyl-D-aspartate receptor (NMDAR) antagonism on human tendon derived cells.

    PubMed

    Dean, Benjamin John Floyd; Snelling, Sarah J B; Dakin, Stephanie Georgina; Javaid, Muhammad Kassim; Carr, Andrew Jonathan

    2015-10-01

    It is known that extracellular glutamate concentrations are increased in tendinopathy but the effects of glutamate upon human tendon derived cells are unknown. The primary purpose was to investigate the effect of glutamate exposure on human tendon-derived cells in terms of viability, protein, and gene expression. The second purpose was to assess whether NMDAR antagonism would affect the response of tendon-derived cells to glutamate exposure. Human tendon-derived cells were obtained from supraspinatus tendon tissue obtained during rotator cuff repair (tendon tear derived cells) and from healthy hamstring tendon tissue (control cells). The in vitro impact of glutamate exposure and NMDAR antagonism (MK-801) was measured using the Alamar blue cell viability assay, immunocytochemistry, and quantitative real-time PCR. Glutamate reduced cell viability at 24?h in tendon tear derived cells but not in control cells at concentrations of 7.5?mM and above. Cell viability was significantly reduced after 72?h of 1.875?mM glutamate in both cell groups; this deleterious effect was attenuated by NMDAR antagonism with 10?µM MK-801. Both 24 and 72?h of 1.875?mM glutamate exposure reduced Type 1 alpha 1 collagen (COL1A1) and Type 3 alpha 1 collagen (COL3A1) gene expression, but increased Aggrecan gene expression. We propose that these effects of glutamate on tendon derived cells including reduced cell viability and altered matrix gene expression contribute to the pathogenesis of tendinopathy. PMID:26041147

  3. Tear-ducts in wine

    NASA Astrophysics Data System (ADS)

    Bush, John W. M.

    1999-11-01

    We examine the radial spoke pattern evident in the meniscus region in glasses of strong alcoholic beverages exhibiting the `tears-in-wine' phenomenon. We demonstrate that the pattern results from ridge-like elevations of the free surface which are supported by evaporatively-driven Marangoni convection in the meniscus region. Vortices associated with the convective motions are aligned in the radial direction by the surface tension gradient responsible for the generation of tears. The radial flow is focussed into the ridges, which thus serve as the principal conduits of fluid for the tears; consequently, we refer to the ridges as `tear-ducts'. The phenomenon is examined experimentally, and a numerical model of evaporatively-driven Marangoni convection is developed which reproduces the salient features of the tear-duct phenomenon.

  4. Parameters influencing prevalence and outcome of tendonitis in Thoroughbred and Arabian racehorses.

    PubMed

    Kalisiak, O

    2012-01-01

    Flexor tendonitis and suspensory desmitis are among most prevalent musculoskeletal injuries observed in racehorses. The aim of this study was to determine which horse and race-related parameters can help to diminish the possibility of injury or--when injury has occurred--to evaluate the potential for the horse to continue a successful career after convalescence. Special attention was given to the comparison of Arabian and Thoroughbred racehorses. 187 horses with ultrasonographically visible lesions were included in the study. Following parameters were analyzed: structure (Superficial Digital Flexor Tendon [SDFT], Deep Digital Flexor Tendon [DDFT], Suspensory Ligament [SL]); percentage of cross sectional area increase; hypoechogenic lesion character; in horses with SDF tendonitis - tendonitis grade according to Genovese. This study showed that Thoroughbreds are more at risk of musculoskeletal problems than Arabian racehorses. In both breeds, the most frequent injuries concern SDFT, then SL. Over 95% of tendonitis concern forelimbs. In Thoroughbreds, the prevalence of tendonitis is higher in bigger horses, in males when compared to females and in fence/steeple racehorses when compared to flat track racehorses. The inside limb is more at risk of SDF tendonitis, when the external limb - of SL desmitis. Tendonitis severity increases with age and is greater in steeplechasers when compared to flat track racehorses. The outcome of tendonitis without hypoechogenic lesion is much better than that with hypoechogenic lesion. Evaluation of hypoechogenic lesion length is an easy and accurate prognosis tool, as the chances of returning to racing drop dramatically with lesions longer than 12 cm. PMID:22708365

  5. Miscellaneous conditions of tendons, tendon sheaths, and ligaments.

    PubMed

    Dyson, S J; Dik, K J

    1995-08-01

    The use of diagnostic ultrasonography has greatly enhances our ability to diagnose injuries of tendons and tendon sheaths that were previously either unrecognized or poorly understood. For may of these injuries, there is currently only a small amount of follow-up data. This article considers injuries of the deep digital flexor tendon and its accessory ligament, the carpal tunnel syndrome soft tissue swellings on the dorsal aspect of the carpus, intertubercular (bicipital) bursitis and bicipital tendinitis, injuries of the gastrocnemius tendon, common calcaneal tendinitis, rupture of peroneus (fibularis tertius) and ligaments injuries of the back. PMID:7584739

  6. Evaluation of the Effusion within Biceps Long Head Tendon Sheath Using Ultrasonography

    PubMed Central

    Park, In; Lee, Hyo-Jin; Kim, Sung-Eun; Bae, Sung-Ho; Lee, Kwang-Yeol; Park, Kwang-Sun

    2015-01-01

    Background Many shoulder diseases are related to glenohumeral joint synovitis and effusion. The purpose of the present study is to detect effusion within the biceps long head tendon sheath as the sign of glenohumeral joint synovitis using ultrasonography, and to evaluate the clinical meaning of effusion within the biceps long head tendon sheath. Methods A consecutive series of 569 patients who underwent ultrasonography for shoulder pain were reviewed retrospectively and ultimately, 303 patients were included. The authors evaluated the incidence and amount of the effusion within the biceps long head tendon sheath on the ultrasonographic short axis view. Furthermore, the authors evaluated the correlation between the amount of effusion within the biceps long head tendon sheath and the range of motion and the functional score. Results The effusion within the biceps long head tendon sheath was detected in 58.42% of the patients studied: 69.23% in adhesive capsulitis, 56.69% in rotator cuff tear, 41.03% in calcific tendinitis, and 33.33% in biceps tendinitis. The average amount of the effusion within the biceps long head tendon sheath was 1.7 ± 1.6 mm, and it was measured to be the largest in adhesive capsulitis. The amount of effusion within biceps long head tendon sheath showed a moderate to high degree of correlation with the range of motion, and a low degree of correlation with the functional score and visual analogue scale for pain in each type of shoulder disease. Conclusions The effusion within the biceps long head tendon sheath is closely related to the range of motion and clinical scores in patients with painful shoulders. Ultrasonographic detection of the effusion within the biceps long head tendon sheath might be a simple and easy method to evaluate shoulder function. PMID:26330958

  7. Scaffolds in Tendon Tissue Engineering

    PubMed Central

    Longo, Umile Giuseppe; Lamberti, Alfredo; Petrillo, Stefano; Maffulli, Nicola; Denaro, Vincenzo

    2012-01-01

    Tissue engineering techniques using novel scaffold materials offer potential alternatives for managing tendon disorders. Tissue engineering strategies to improve tendon repair healing include the use of scaffolds, growth factors, cell seeding, or a combination of these approaches. Scaffolds have been the most common strategy investigated to date. Available scaffolds for tendon repair include both biological scaffolds, obtained from mammalian tissues, and synthetic scaffolds, manufactured from chemical compounds. Preliminary studies support the idea that scaffolds can provide an alternative for tendon augmentation with an enormous therapeutic potential. However, available data are lacking to allow definitive conclusion on the use of scaffolds for tendon augmentation. We review the current basic science and clinical understanding in the field of scaffolds and tissue engineering for tendon repair. PMID:22190961

  8. Wide-Awake Primary Flexor Tendon Repair, Tenolysis, and Tendon Transfer

    PubMed Central

    2015-01-01

    Tendon surgery is unique because it should ensure tendon gliding after surgery. Tendon surgery now can be performed under local anesthesia without tourniquet, by injecting epinephrine mixed with lidocaine, to achieve vasoconstriction in the area of surgery. This method allows the tendon to move actively during surgery to test tendon function intraoperatively and to ensure the tendon is properly repaired before leaving the operating table. I applied this method to primary flexor tendon repair in zone 1 or 2, tenolysis, and tendon transfer, and found this approach makes tendon surgery easier and more reliable. This article describes the method that I have used for tendon surgery. PMID:26330947

  9. Biomechanical analysis of the effect of varying suture pitch in tendon graft fixation.

    PubMed

    Jassem, M; Rose, A T; Meister, K; Indelicato, P A; Wheeler, D

    2001-01-01

    The purpose of this study was to biomechanically assess the effect of varying suture pitch on the holding power of the Krackow suture technique for tendon graft fixation. Seven pairs of rabbit Achilles tendons were sutured with single No. 5 Ti-Cron suture using the Krackow technique. One tendon from each pair was sutured using a 0.5-cm suture pitch (half-pitch group) while the contralateral tendon from each pair was sutured with a 1.0-cm suture pitch (one-pitch group). The tendons were loaded to failure using a servohydraulic materials test system at a loading rate of 0.5 mm/sec. There were no statistically significant differences noted in suture slippage at failure (1.58 cm for half pitch versus 1.45 cm for one pitch) or maximal force to failure (158.5 N for half pitch versus 168.2 N one pitch) between the two treatment groups. However, the construct with the 1-cm suture pitch was significantly stiffer than the construct with the 0.5-cm suture pitch, with stiffness values of 106.2 N/cm and 91.4 N/cm, respectively. The most common mechanism of failure was slippage of the suture at the first suture throw and tearing of the first knot through the most distal portion of the tendon. Four constructs failed by suture rupture, two from each experimental group. PMID:11734486

  10. 49 CFR 178.818 - Tear test.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 49 Transportation 3 2013-10-01 2013-10-01 false Tear test. 178.818 Section 178.818 Transportation... Tear test. (a) General. The tear test must be conducted for the qualification of all flexible IBC design types. (b) Special preparation for the tear test. The flexible IBC must be filled to not less...

  11. 49 CFR 178.818 - Tear test.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 3 2011-10-01 2011-10-01 false Tear test. 178.818 Section 178.818 Transportation... Tear test. (a) General. The tear test must be conducted for the qualification of all flexible IBC design types. (b) Special preparation for the tear test. The flexible IBC must be filled to not less...

  12. 49 CFR 178.818 - Tear test.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 2 2010-10-01 2010-10-01 false Tear test. 178.818 Section 178.818 Transportation... § 178.818 Tear test. (a) General. The tear test must be conducted for the qualification of all flexible IBC design types. (b) Special preparation for the tear test. The flexible IBC must be filled to...

  13. Correlation of acromial morphology with impingement syndrome and rotator cuff tears

    PubMed Central

    2013-01-01

    Background and purpose Indications for acromioplasty are based on clinical symptoms and are generally supported by typical changes in acromial morphology on standard radiographs. We evaluated 5 commonly used radiographic parameters of acromial morphology and assessed the association between different radiographic characteristics on the one hand and subacromial impingement or rotator cuff tears on the other. Patients and methods We measured acromial type (Bigliani), acromial slope (AS), acromial tilt (AT), lateral acromial angle (LAA), and acromion index (AI) on standard radiographs from 50 patients with full-thickness supraspinatus tendon tears, 50 patients with subacromial impingement, and 50 controls without subacromial pathology. Results The acromial type according to Bigliani was not associated with any particular cuff lesion. A statistically significant difference between controls and impingement patients was found for AS. AT of controls was significantly smaller than that of impingement patients and cuff-tear patients. LAA of cuff-tear patients differed significantly from that of controls and impingement patients, but LAA of controls was not significantly different from that of impingement patients. Differences between impingement patients and cuff-tear patients were also significant. AI of controls was significantly lower than of impingement patients and of cuff-tear patients. A good correlation was found between acromial type and AS. Interpretation A low lateral acromial angle and a large lateral extension of the acromion were associated with a higher prevalence of impingement and rotator cuff tears. An extremely hooked anterior acromion with a slope of more than 43° and an LAA of less than 70° only occurred in patients with rotator cuff tears. PMID:23409811

  14. Greater tuberosity notch: an important indicator of articular-side partial rotator cuff tears in the shoulders of throwing athletes.

    PubMed

    Nakagawa, S; Yoneda, M; Hayashida, K; Wakitani, S; Okamura, K

    2001-01-01

    We examined the location of rotator cuff tears, associated labral injuries, and notches on the greater tuberosity of the humeral head in shoulders of throwing athletes. Arthroscopic findings (rotator cuff tear, labral condition, and greater tuberosity notch) as well as other factors (duration of playing baseball, range of motion, and joint laxity) of 61 baseball players were retrospectively studied. The presence of a greater tuberosity notch was also evaluated for by plain radiographs. Forty patients had articular-side partial rotator cuff tears, most of which occurred in the interval between the supraspinatus and infraspinatus tendons. The existence of a rotator cuff tear was not related to the range of motion, joint laxity, the detachment of the superior glenoid labrum, or posterosuperior labral injury. Greater tuberosity notches were recognized in 38 shoulders by arthroscopy and most were detected on plain radiographs. The presence of a notch was significantly related to the existence of a rotator cuff tear, while the size of the notch was significantly related to the depth and width of the tear. The greater tuberosity notch seems to be one of the most important diagnostic indicators for a rotator cuff tear in throwing athletes. PMID:11734490

  15. Alteration of the material properties of the normal supraspinatus tendon by nicotine treatment in a rat model

    PubMed Central

    2010-01-01

    Background and purpose Several studies have shown that nicotine has a detrimental effect on the development of rotator cuff tear. However, little is known about its mechanism. We evaluated the effect of nicotine on the maximum tensile load, the maximum tensile stress, and the elastic modulus of the supraspinatus tendon in a rat model. Methods 27 rats were randomly assigned to 3 groups. Subcutaneously implanted osmotic pumps delivered two different concentrations of nicotine solution (high dose: 45 ng/mL; low dose: 22.5 ng/mL) or saline solution (controls) over a 12-week period. The level of serum cotinine, a breakdown product of nicotine, was evaluated. We performed tensile testing using the left supraspinatus tendon in each rat. The maximum load of the supraspinatus tendon was measured, and the maximum tensile stress and elastic modulus were calculated. Results Serum cotinine levels showed controlled systemic release of nicotine. The maximum tensile load and stress were similar in the three groups. The elastic modulus was, however, higher in the nicotine groups than in the control group. Interpretation In a rat model, ncotine caused a change in the material properties of the supraspinatus tendon. This change may predispose to a tear in the supraspinatus tendon. PMID:20919810

  16. Achilles Tendon Rupture

    PubMed Central

    Wertz, Jess; Galli, Melissa; Borchers, James R.

    2013-01-01

    Context: Achilles tendon (AT) rupture in athletes is increasing in incidence and accounts for one of the most devastating sports injuries because of the threat to alter or end a career. Despite the magnitude of this injury, reliable risk assessment has not been clearly defined, and prevention strategies have been limited. The purpose of this review is to identify potential intrinsic and extrinsic risk factors for AT rupture in aerial and ground athletes stated in the current literature. Evidence Acquisition: A MEDLINE search was conducted on AT rupture, or “injury” and “risk factors” and “athletes” from 1980 to 2011. Emphasis was placed on epidemiology, etiology, and review articles focusing on the risk for lower extremity injury in runners and gymnasts. Thirty articles were reviewed, and 22 were included in this assessment. Results: Aerial and ground athletes share many intrinsic risk factors for AT rupture, including overuse and degeneration of the tendon as well as anatomical variations that mechanically put an athlete at risk. Older athletes, athletes atypical in size for their sport, high tensile loads, leg dominance, and fatigue also may increase risk. Aerial athletes tend to have more extrinsic factors that play a role in this injury due to the varying landing surfaces from heights and technical maneuvers performed at various skill levels. Conclusion: Risk assessment for AT rupture in aerial and ground athletes is multivariable and difficult in terms of developing prevention strategies. Quantitative measures of individual risk factors may help identify major contributors to injury. PMID:24427410

  17. The Trapped Medial Meniscus Tear

    PubMed Central

    Herschmiller, Thomas A.; Anderson, John A.; Garrett, William E.; Taylor, Dean C.

    2015-01-01

    Background: Numerous clinical examination maneuvers have been developed to identify meniscus tears of the knee. While meniscus injuries vary significantly in type and severity, no maneuvers have been developed that help to distinguish particular tear characteristics. Purpose: This nonconsecutive case series highlights a distinctive clinical finding that correlates with inferiorly displaced flap tears of the medial meniscus that become trapped in the medial gutter of the knee, as identified through magnetic resonance imaging (MRI) and arthroscopy. Study Design: Cohort study (diagnosis); Level of evidence, 3. Methods: Eight patients with trapped medial meniscus tears were identified from a single surgeon’s academic orthopaedic sports medicine practice between January 2009 and January 2012. Each patient underwent clinical evaluation, MRI, and arthroscopic treatment for meniscus injury. Clinical notes, MRI images, radiology reports, and operative findings were reviewed and compared in a descriptive fashion. Results: Each patient displayed a positive clinical examination finding of medial knee pain inferior to the joint line with flexion and the application of valgus stress in the setting of a torn medial meniscus and intact medial collateral ligament (MCL). Preoperative MRI revealed a distinctive flap tear of the medial meniscus flipped inferiorly to lay trapped between the tibia and deep fibers of the MCL. On arthroscopy, flap tears were found displaced inferiorly and trapped in the medial gutter in 6 of the 8 patients. Displaced meniscal fragments in the remaining 2 patients were found within the medial compartment. Conclusion: Inferiorly displaced flap tears of the meniscus that have been displaced to the medial gutter can be localized through a careful examination technique. Clinical Relevance: Early identification of this injury pattern may help reduce the likelihood that the trapped fragment will be missed during arthroscopy.

  18. [Pathophysiology of overuse tendon injury].

    PubMed

    Kannus, P; Paavola, M; Paakkala, T; Parkkari, J; Järvinen, T; Järvinen, M

    2002-10-01

    Overuse tendon injury is one of the most common injuries in sports. The etiology as well as the pathophysiological mechanisms leading to tendinopathy are of crucial medical importance. At the moment intrinsic and extrinsic factors are assumed as mechanisms of overuse tendon injury. Except for the acute, extrinsic trauma, the chronic overuse tendon injury is a multifactorial process. There are many other factors, such as local hypoxia, less of nutrition, impaired metabolism and local inflammatory that may also contribute to the development of tissue damage. The exact interaction of these factors cannot be explained entirely at the moment. Further studies will be necessary in order to get more information. PMID:12402104

  19. Rectus Femoris Tendon Calcification

    PubMed Central

    Zini, Raul; Panascì, Manlio; Papalia, Rocco; Franceschi, Francesco; Vasta, Sebastiano; Denaro, Vincenzo

    2014-01-01

    Background: Since it was developed, hip arthroscopy has become the favored treatment for femoroacetabular impingement. Due to recent considerable improvements, the indications for this technique have been widely extended. Injuries of the rectus femoris tendon origin, after an acute phase, could result in a chronic tendinopathy with calcium hydroxyapatite crystal deposition, leading to pain and loss of function. Traditionally, this condition is addressed by local injection of anesthetic and corticosteroids or, when conservative measures fail, by open excision of the calcific lesion by an anterior approach. Purpose: To assess whether arthroscopic excision of calcification of the proximal rectus is a safe and effective treatment. Study Design: Case series; Level of evidence, 4. Methods: Outcomes were studied from 6 top amateur athletes (age range, 30-43 years; mean, 32.6 years) affected by calcification of the proximal rectus who underwent arthroscopic excision of the calcification. Patients were preoperatively assessed radiographically, and diagnosis was confirmed by a 3-dimensional computed tomography scan. To evaluate the outcome, standardized hip rating scores were used pre- and postoperatively (at 6 and 12 months): the Hip disability and Osteoarthritis Outcome Score, Oxford Hip Score, and Modified Harris Hip Score. Moreover, visual analog scales (VAS) for pain, sport activity level (SAL), and activities of daily living (ADL) were also used. Results: One year after surgery, all patients reported satisfactory outcomes, with 3 of 6 rating their return-to-sport level as high as preinjury level, and the remaining 3 with a percentage higher than 80%. Five patients ranked their ability to carry on daily activities at 100%. Statistical analysis showed significant improvement of the Oxford Hip Score, the Modified Harris Hip Score, and all 3 VAS subscales (pain, SAL, and ADL) from pre- to latest postoperative assessment (P < .05). Conclusion: Arthroscopic excision of rectus femoris tendon calcification yields satisfying results with few risks to the patient as well as rapid recovery. Clinical Relevance: The recent improvements in hip arthroscopy give the opportunity to address an increasing number of hip conditions effectively and safely, with rapid recovery for the patient. Arthroscopic excision of rectus femoris tendon calcification can be considered a feasible option, with few risks to the patient, rapid recovery, and satisfying outcomes. PMID:26535288

  20. Tendon, tendon sheath, and ligament injuries in the pastern.

    PubMed

    Dyson, S J; Denoix, J M

    1995-08-01

    The palmar (plantar) aspect of the pastern is an anatomically complex area and an understanding of this is a prerequisite for accurate diagnosis of injuries in this area. The gross and normal ultrasonographic anatomy are described, and injuries of the superficial and deep digital flexor tendons and the digital flexor tendon sheath, the distal sesamoidean ligaments, and the palmar ligaments of the proximal interphalangeal joint are discussed. PMID:7584735

  1. Epidemiology of the rotator cuff tears: a new incidence related to thyroid disease

    PubMed Central

    Oliva, Francesco; Osti, Leonardo; Padulo, Johnny; Maffulli, Nicola

    2014-01-01

    Summary Background: in the last years the incidence of rotator cuff tears increased and one main cause still waiting to be clarified. Receptors for thyroid hormones in rotator cuff tendons suggest possible effects on tendons metabolism and status. We undertook a retrospective, observational cohort study of 441 patients who underwent arthroscopic and mini-open repair for non traumatic degenerative rotator cuff tears. Methods: all the patients, predominantly females (63%), were interview to assess the relationship (frequency for class age “20 yrs” and factor analysis) between lesions of the rotator cuff with the following variables: gender, thyroid disease, smoker, taking medications for diabetes, hypertension or high cholesterol; presence of associated conditions (diabetes, hypertension, hypercholesterolemia). Results: thyroid disease is highly frequently (until 63% for 60<80 yrs) in females group independent to the age. Conversely, males showed a high frequency for smoker 37<62% until 80 yrs and 50% hypercholesterolemia over 80 yrs for the clinical variable studied. Conclusions: this is the first clinical report that shown a relationship between thyroid pathologies and non-traumatic rotator cuff tear as increased risk factors. PMID:25489548

  2. Wear and Tear - Mechanical

    NASA Technical Reports Server (NTRS)

    Swanson, Theodore

    2008-01-01

    The focus of this chapter is on the long term wear and tear, or aging, of the mechanical subsystem of a spacecraft. The mechanical subsystem is herein considered to be the primary support structure (as in a skeleton or exoskeleton) upon which all other spacecraft systems rest, and the associated mechanisms. Mechanisms are devices which have some component that moves at least once, in response to some type of passive or active control system. For the structure, aging may proceed as a gradual degradation of mechanical properties and/or function, possibly leading to complete structural failure over an extended period of time. However, over the 50 years of the Space Age such failures appear to be unusual. In contrast, failures for mechanisms are much more frequent and may have a very serious effect on mission performance. Just as on Earth, all moving devices are subject to normal (and possibly accelerated) degradation from mechanical wear due to loss or breakdown of lubricant, misalignment, temperature cycling effects, improper design/selection of materials, fatigue, and a variety of other effects. In space, such environmental factors as severe temperature swings (possibly 100's of degrees C while going in and out of direct solar exposure), hard vacuum, micrometeoroids, wear from operation in a dusty or contaminated environment, and materials degradation from radiation can be much worse. In addition, there are some ground handling issues such as humidity, long term storage, and ground transport which may be of concern. This chapter addresses the elements of the mechanical subsystem subject to wear, and identifies possible causes. The potential impact of such degradation is addressed, albeit with the recognition that the impact of such wear often depends on when it occurs and on what specific components. Most structural elements of the mechanical system typically are conservatively designed (often to a safety factor of greater than approximately 1.25 on yield for unmanned spacecraft) but do not have backup structure due to the added mass this would impose, and also due to the fact that structural elements can be accurately modeled mathematically and in test. Critical mechanisms or devices may have backups, or alternate work-arounds, since characterization of these systems in a 1g environment is less accurate than structure, and repair in-space is often impossible.

  3. Posterior Tibial Tendon Dysfunction (PTTD)

    MedlinePLUS

    ... ACFAS | Información en Español Advanced Search Home » Foot & Ankle Conditions » Posterior Tibial Tendon Dysfunction (PTTD) Text Size ... the arch, and an inward rolling of the ankle. As the condition progresses, the symptoms will change. ...

  4. Tear exchange and contact lenses: A review

    PubMed Central

    Muntz, Alex; Subbaraman, Lakshman N.; Sorbara, Luigina; Jones, Lyndon

    2015-01-01

    Tear exchange beneath a contact lens facilitates ongoing fluid replenishment between the ocular surface and the lens. This exchange is considerably lower during the wear of soft lenses compared with rigid lenses. As a result, the accumulation of tear film debris and metabolic by-products between the cornea and a soft contact lens increases, potentially leading to complications. Lens design innovations have been proposed, but no substantial improvement in soft lens tear exchange has been reported. Researchers have determined post-lens tear exchange using several methods, notably fluorophotometry. However, due to technological limitations, little remains known about tear hydrodynamics around the lens and, to-date, true tear exchange with contact lenses has not been shown. Further knowledge regarding tear exchange could be vital in aiding better contact lens design, with the prospect of alleviating certain adverse ocular responses. This article reviews the literature to-date on the significance, implications and measurement of tear exchange with contact lenses. PMID:25575892

  5. Tearing of thin polyimide films

    NASA Technical Reports Server (NTRS)

    Hinkley, J. A.; Hoogstraten, C. A.

    1987-01-01

    Films of BTDA-ODA polyimide up to 58 microns thick were torn at constant cross-head speed in 'trousers' tests. In common with previous results on polyolefins, the work of tearing was found to increase markedly with specimen thickness. A model for the increase, based on the volume of plastically deformed material adjacent to the crack plane, was found to be only qualitatively valid. The experimental slope of a plot of tearing energy (per unit area) against thickness was 70 MJ/cu m. Optical and scanning electron micrographs of torn films are discussed in regard to the modes of failure.

  6. Management of Extensor Tendon Injuries

    PubMed Central

    Griffin, M; Hindocha, S; Jordan, D; Saleh, M; Khan, W

    2012-01-01

    Extensor tendon injuries are very common injuries, which inappropriately treated can cause severe lasting impairment for the patient. Assessment and management of flexor tendon injuries has been widely reviewed, unlike extensor injuries. It is clear from the literature that extensor tendon repair should be undertaken immediately but the exact approach depends on the extensor zone. Zone I injuries otherwise known as mallet injuries are often closed and treated with immobilisaton and conservative management where possible. Zone II injuries are again conservatively managed with splinting. Closed Zone III or ‘boutonniere’ injuries are managed conservatively unless there is evidence of displaced avulsion fractures at the base of the middle phalanx, axial and lateral instability of the PIPJ associated with loss of active or passive extension of the joint or failed non-operative treatment. Open zone III injuries are often treated surgically unless splinting enable the tendons to come together. Zone V injuries, are human bites until proven otherwise requires primary tendon repair after irrigation. Zone VI injuries are close to the thin paratendon and thin subcutaneous tissue which strong core type sutures and then splinting should be placed in extension for 4-6 weeks. Complete lacerations to zone IV and VII involve surgical primary repair followed by 6 weeks of splinting in extension. Zone VIII require multiple figure of eight sutures to repair the muscle bellies and static immobilisation of the wrist in 45 degrees of extension. To date there is little literature documenting the quality of repairing extensor tendon injuries however loss of flexion due to extensor tendon shortening, loss of flexion and extension resulting from adhesions and weakened grip can occur after surgery. This review aims to provide a systematic examination method for assessing extensor injuries, presentation and management of all type of extensor tendon injuries as well as guidance on mobilisation pre and post surgery. PMID:22431949

  7. Efficacy of a mesenchymal stem cell loaded surgical mesh for tendon repair in rats

    PubMed Central

    2014-01-01

    Objectives The purpose of this study was to investigate the efficacy of a composite surgical mesh for delivery of mesenchymal stem cells (MSCs) in tendon repair. Methods The MSC-loaded mesh composed of a piece of conventional surgical mesh and a layer of scaffold, which supported MSC-embedded alginate gel. A 3-mm defect was surgically created at the Achilles tendon-gastrocnemius/soleus junction in 30 rats. The tendon defects were repaired with either 1) MSC-loaded mesh; or 2) surgical mesh only; or 3) routine surgical suture. Repaired tendons were harvested at days 6 and 14 for histology, which was scored on the bases of collagen organization, vascularity and cellularity, and immunohistochemisty of types I and III collagen. Results In comparison with the other two repair types, at day 6, the MSC-loaded mesh significantly improved the quality of the repaired tendons with dense and parallel collagen bundles, reduced vascularity and increased type I collagen. At day 14, the MSC-loaded mesh repaired tendons had better collagen formation and organization. Conclusion The MSC-loaded mesh enhanced early tendon healing, particularly the quality of collagen bundles. Application of the MSC-loaded mesh, as a new device and MSC delivery vehicle, may benefit to early functional recovery of the ruptured tendon. PMID:24884819

  8. Triceps Tendon Ruptures Requiring Surgical Repair in National Football League Players

    PubMed Central

    Finstein, Joseph L.; Cohen, Steven B.; Dodson, Christopher C.; Ciccotti, Michael G.; Marchetto, Paul; Pepe, Matthew D.; Deluca, Peter F.

    2015-01-01

    Background: Complete triceps tendon ruptures are relatively rare in the general population but slightly more prevalent in professional football. One prior study found 11 complete ruptures over a 6-season period. Hypothesis: Triceps ruptures occur more commonly in football linemen due to forced elbow flexion during an eccentric contraction and may occur more commonly with the increasing size and speed of professional players. Surgical repair allows full return to sports, but with a lengthy recovery time. Study Design: Case series; Level of evidence, 4. Methods: A search of the National Football League Injury Surveillance System (NFLISS) found a total of 37 triceps tendon ruptures requiring surgical repair from the years 2000 to 2009. Data were obtained for setting of injury, player position, activity causing injury, play type, time of game when injury occurred, height, weight, body mass index (BMI), and number of days lost from football. Results: There were 37 players requiring surgical repair for triceps tendon ruptures over the 10-season period. The average height, weight, and BMI of the players were 75 inches, 292 pounds, and 36.5 kg/m2, respectively. The majority of players were linemen (86%): 16 defensive, 15 offensive, and 1 tight end. The injury took place while blocking or being blocked in 29 players (78%) and while tackling or being tackled in 5 players (14%). Players missed an average of 165 days (range, 49-318 days) from football as a result of their injury and surgery. Conclusion: Triceps tendon tears requiring surgical repair are more common in professional football players than in the general population and are occurring more commonly than previously reported. Surgical repair allows return to play. Clinical Relevance: Our study identifies the rate of triceps tendon tears requiring repair in the NFL according to position, identifying which players may be most at risk for this injury. PMID:26535394

  9. Arthroscopic transtendinous repair of articular-sided pasta (partial articular supraspinatus tendon avulsion) injury

    PubMed Central

    Wang, Yi; Lu, Liangyu; Lu, Zhe; Xiao, Lei; Kang, Yifan; Wang, Zimin

    2015-01-01

    Objective: To evaluate clinical efficacy of arthroscopic transtendinous repair of partial articular-sided PASTA (partial articular supraspinatus tendon avulsion) injury. Methods: From February 2011 to July 2014, 12 cases of PASTA, aged 29 to 72 years with an average of 52.9 ± 13.3 years, were treated arthoscopically. To repair PASTA, articular-sided rotator cuff tear was explored, injury site was punctured and labeled with PDS absorbable monofilament suture (Ethicon, Somerville, NJ, USA) suture, subacromial bursa was cleaned up with acromioplasty, and integrity of bursa-side rotator cuff was assessed. Then with arthroscope in glenohumeral joint, footprint of the bursa-side supraspinatus tendon was preserved, rivets were introduced into the joint through supraspinatus tendon, joint-side partial tear was sutured, and anatomical reconstruction of the rotator cuff footprint was established. The patients were followed up post-operatively for 12-36 months, average 22 ± 7.3 months. The clinical outcomes were emulated with ASES (American Shoulder and Elbow Surgeons) Shoulder Score system and UCLA (University of California at Los Angeles) Shoulder rating scale. Results: The post-operative ASES score was 89.7 ± 5.6, higher than the pre-operative one 49.8 ± 9.8 (t = 12.25, P <0.0001). While UCLA scale increased from the pre-operative 17.3, ± 3.3 to the post-operative 30.4 ± 3.2 points (t = 9.87, P <0.0001), with a satisfaction rate of 11/12 (91.7%). Conclusion: Trans-tendon repair is ideal for PASTA with advantage of maximal preservation of the normal rotator cuff tissue, anatomical reconstruction of the rotator cuff footprint and stable fixation of tendon-bone interface. PMID:25784979

  10. Proximal coracobrachialis tendon rupture, subscapularis tendon rupture, and medial dislocation of the long head of the biceps tendon in an adult after traumatic anterior shoulder dislocation.

    PubMed

    Saltzman, Bryan M; Harris, Joshua D; Forsythe, Brian

    2015-01-01

    Rupture of the coracobrachialis is a rare entity, in isolation or in combination with other muscular or tendinous structures. When described, it is often a result of direct trauma to the anatomic area resulting in rupture of the muscle belly. The authors present a case of a 57-year-old female who suffered a proximal coracobrachialis tendon rupture from its origin at the coracoid process, with concomitant subscapularis tear and medial dislocation of the long head of biceps tendon after first time traumatic anterior shoulder dislocation. Two weeks after injury, magnetic resonance imaging suggested the diagnosis, which was confirmed during combined arthroscopic and open technique. Soft-tissue tenodesis of coracobrachialis to the intact short head of the biceps, tenodesis of the long head of biceps to the intertubercular groove, and double-row anatomic repair of the subscapularis were performed. The patient did well postoperatively, and ultimately at 6 months follow-up, she was without pain, and obtained 160° of active forward elevation, 45° of external rotation, internal rotation to T8, 5/5 subscapularis and biceps strength. Scoring scales had improved from the following preoperative to final follow-up: American Shoulder and Elbow Surgeons, 53.33-98.33; constant, 10-100; visual analogue scale-pain, 4-0. DASH score was 5. PMID:25937715

  11. Proximal coracobrachialis tendon rupture, subscapularis tendon rupture, and medial dislocation of the long head of the biceps tendon in an adult after traumatic anterior shoulder dislocation

    PubMed Central

    Saltzman, Bryan M.; Harris, Joshua D.; Forsythe, Brian

    2015-01-01

    Rupture of the coracobrachialis is a rare entity, in isolation or in combination with other muscular or tendinous structures. When described, it is often a result of direct trauma to the anatomic area resulting in rupture of the muscle belly. The authors present a case of a 57-year-old female who suffered a proximal coracobrachialis tendon rupture from its origin at the coracoid process, with concomitant subscapularis tear and medial dislocation of the long head of biceps tendon after first time traumatic anterior shoulder dislocation. Two weeks after injury, magnetic resonance imaging suggested the diagnosis, which was confirmed during combined arthroscopic and open technique. Soft-tissue tenodesis of coracobrachialis to the intact short head of the biceps, tenodesis of the long head of biceps to the intertubercular groove, and double-row anatomic repair of the subscapularis were performed. The patient did well postoperatively, and ultimately at 6 months follow-up, she was without pain, and obtained 160° of active forward elevation, 45° of external rotation, internal rotation to T8, 5/5 subscapularis and biceps strength. Scoring scales had improved from the following preoperative to final follow-up: American Shoulder and Elbow Surgeons, 53.33-98.33; constant, 10-100; visual analogue scale-pain, 4-0. DASH score was 5. PMID:25937715

  12. Histopathological findings in chronic tendon disorders.

    PubMed

    Järvinen, M; Józsa, L; Kannus, P; Järvinen, T L; Kvist, M; Leadbetter, W

    1997-04-01

    Tendon injuries and other tendon disorders represent a common diagnostic and therapeutic challenge in sports medicine, resulting in chronic and long-lasting problems. Tissue degeneration is a common finding in many sports-related tendon complaints. In the great majority of spontaneous tendon ruptures, chronic degenerative changes are seen at the rupture site of the tendon (1). Systemic diseases and diseases specifically deteriorating the normal structure of the tendon (i.e. foreign bodies, and metabolic, inherited and infectious tendon diseases) are only rarely the cause of tendon pathology. Inherited diseases, such as various hereditary diseases with disturbed collagen metabolism and characteristic pathological structural alterations (Ehlers-Danlos syndrome, Marfani syndrome, homocystinuria (ochronosis)), represent approximately 1% of the causes of chronic tendon complaints (2), whereas foreign bodies are somewhat more common and are found in less than 10% of all chronic tendon problems (1). Rheumatoid arthritis and sarcoidosis are typical systemic diseases that cause chronic inflammation in tendon and peritendinous tissues. Altogether, these 'specific' disorders represented less than 2% of the pathological alterations found in the histological analysis of more than 1000 spontaneously ruptured tendons (1, 3, 4). In this material, degenerative changes were seen in a great majority of the tendons, indicating that a spontaneous tendon rupture is a typical clinical end-state manifestation of a degenerative process in the tendon tissue. The role of overuse in the pathogenesis of chronic tendon injuries and disorders is not completely understood. It has been speculated that when tendon is overused it becomes fatigued and loses its basal reparative ability, the repetitive microtraumatic processes thus overwhelming the ability of the tendon cells to repair the fiber damage. The intensive repetitive activity, which often is eccentric by nature, may lead to cumulative microtrauma which further weakens the collagen cross-linking, non-collagenous matrix, and vascular elements of the tendon. Overuse has also been speculated to cause chronic tendon problems, by disturbing the micro- and macrovasculature of the tendon and resulting in insufficiency in the local blood circulation. Decreased blood flow simultaneous with an increased activity may result in local tissue hypoxia, impaired nutrition and energy metabolism, and together these factors are likely to play an important role in the sequence of events leading to tendon degeneration (4). A sedentary lifestyle has been proposed as a main reason for poor basal circulation of the tendon, and presumably is at least partly responsible for the high number of tendon problems in people with a sedentary lifestyle who occasionally take part in high physical activity sports events. PMID:9211609

  13. Prediction of the elastic strain limit of tendons.

    PubMed

    Reyes, A M; Jahr, H; van Schie, H T M; Weinans, H; Zadpoor, A A

    2014-02-01

    The elastic strain limit (ESL) of tendons is the point where maximum elastic modulus is reached, after which micro-damage starts. Study of damage progression in tendons under repetitive (fatigue) loading requires a priori knowledge about ESL. In this study, we propose three different approaches for predicting ESL. First, one single value is assumed to represent the ESL of all tendon specimens. Second, different extrapolation curves are used for extrapolating the initial part of the stress-strain curve. Third, a method based on comparing the shape of the initial part of the stress-strain curve of specimens with a database of stress-strain curves is used. A large number of porcine tendon explants (97) were tested to examine the above-mentioned approaches. The variants of the third approach yielded significantly (p<0.05) smaller error values as compared to the other approaches. The mean absolute percentage error of the best-performing variant of the shape-based comparison was between 8.14±6.44% and 9.96±9.99% depending on the size of the initial part of the stress-strain curves. Interspecies generalizability of the best performing method was also studied by applying it for prediction of the ESL of horse tendons. The ESL of horse tendons was predicted with mean absolute percentage errors ranging between 10.53±7.6% and 19.16±14.31% depending on the size of the initial part of the stress-strain curves and the type of normalization. The results of this study suggest that both ESL and the shape of stress-strain curves may be highly different between different individuals and different anatomical locations. PMID:24362243

  14. Anatomic ACL reconstruction: rectangular tunnel/bone-patellar tendon-bone or triple-bundle/semitendinosus tendon grafting.

    PubMed

    Shino, Konsei; Mae, Tatsuo; Tachibana, Yuta

    2015-05-01

    Anatomic ACL reconstruction is the reasonable approach to restore stability without loss of motion after ACL tear. To mimic the normal ACL like a ribbon, our preferred procedures is the anatomic rectangular tunnel (ART) technique with a bone-patellar tendon-bone (BTB) graft or the anatomic triple bundle (ATB) procedure with a hamstring (HS) tendon graft. It is important to create tunnel apertures inside the attachment areas to lessen the tunnel widening. To identify the crescent-shaped ACL femoral attachment area, the upper cartilage margin, the posterior cartilage margin and the resident's ridge are used as landmarks. To delineate the C-shaped tibial insertion, medial intercondylar ridge, Parson's knob and anterior horn of the lateral meniscus are helpful. In ART-BTB procedure which is suitable for male patients engaged in contact sports, the parallelepiped tunnels with rectangular apertures are made within the femoral and tibial attachment areas. In ATB-HS technique which is mainly applied to female athletes engaged in non-contact sports including skiing or basketball, 2 femoral and 3 tibial round tunnels are created inside the attachment areas. These techniques make it possible for the grafts to run as the native ACL without impingement to the notch or PCL. After femoral fixation with an interference screw or cortical fixation devices including Endobutton, the graft is pretensioned in situ by repetitive manual pulls at 15-20° of flexion, monitoring the graft tension with tensioners on a tensioning boot installed on the calf. Tibial fixation with pullout sutures is achieved using Double Spike Plate and a screw at the pre-determined amount of tension of 10-20N. While better outcomes with less failure rate are being obtained compared to those in the past, higher graft tear rate remains a problem. Improved preventive training may be required to avoid secondary ACL injuries. PMID:25753837

  15. Model of Tearing Mode Suppression by Resonant Magnetic Perturbations in a Tokamak

    NASA Astrophysics Data System (ADS)

    Huang, Wenlong; Zhu, Ping

    2014-10-01

    The conventional error field theory has been extended to model the interaction between tearing mode and resonant magnetic perturbation (RMP) in a tokamak approximated by a screw pinch configuration. The model is applied to the analysis and understanding of the mechanism underlying the tearing mode suppression induced by resonant magnetic perturbation as observed in recent tokamak experiments and simulations. Numerical solutions of the model demonstrate that at lower strength, RMPs are able to reduce the tearing mode amplitude. As the RMP strength increases, the tearing mode is locked in phase and its amplitude jumps to a higher level. Model analysis further reveals that both the tearing mode suppression and the mode locking are achieved through the modulation of the tearing mode rotational frequency using RMPs. The model predictions for the parameter regimes of tearing mode suppression and locking have been examined, and comparisons with recent experimental observations and simulations will be discussed. Supported by Ministry of Science and Technology of P. R. China Grant 2014GB124002.

  16. Tibialis Anterior Tendon Transfer for Posterior Tibial Tendon Insufficiency.

    PubMed

    Ramanujam, Crystal L; Stapleton, John J; Zgonis, Thomas

    2016-01-01

    The Cobb procedure is useful for addressing stage 2 posterior tibial tendon dysfunction and is often accompanied by a medial displacement calcaneal osteotomy and/or lateral column lengthening. The Cobb procedure can also be combined with selected medial column arthrodesis and realignment osteotomies along with equinus correction when indicated. PMID:26590721

  17. Mineralization-related modifications in the calcifying tendons of turkey (Meleagris gallopavo).

    PubMed

    Raspanti, Mario; Reguzzoni, Marcella; Protasoni, Marina; Congiu, Terenzio

    2015-04-01

    The tendons of some birds undergo a physiological process of gradual mineralization, usually limited to the central portion of the tendon and resulting in an increase of the elastic modulus and the ultimate strength. The present study was carried out by light microscopy and scanning electron microscopy and was focused on the structural and ultrastructural modifications occurring in this tissue during biomineralization. In comparison with most other tendons, turkey tendons appeared to be more finely subdivided into thinner fascicles and to contain a greater amount of cell-rich endotenon tissue. The most obvious finding, however, was the complete disappearance of the crimps in the calcified portions of the tendon, while they were present with the usual morphology in the non-mineralized portion. The electron microscopy revealed in the mineralized tendon traces of pre-existing crimps, locked in the straightened-out position by the infiltrating mineral phase. This latter was composed of two different types of fine particles, respectively, growing inside and around the collagen fibrils and appearing as tightly packed platelets or as larger, flat platelets regularly arranged in phase with the D-period of collagen. The perifibrillar mineral could play a critical role in the mechanical coupling of adjoining fascicles and in the transmission of tensile loads along the tendon itself. PMID:25698547

  18. Trends in the Management of Achilles Tendon Ruptures in the United States Medicare Population, 2005-2011

    PubMed Central

    Erickson, Brandon J.; Cvetanovich, Gregory L.; Nwachukwu, Ben U.; Villarroel, Leonardo D.; Lin, Johnny L.; Bach, Bernard R.; McCormick, Frank M.

    2014-01-01

    Background: Achilles tendon ruptures are one of the most commonly treated injuries by orthopaedic surgeons and general practitioners. Achilles tendon ruptures have classically been thought to affect the middle-aged “weekend warrior” participating in basketball, volleyball, soccer, or any other ground sport that requires speed and agility; however, with a more active elderly population, these tears are becoming more common in older patients. Purpose: To report trends in nonoperative and operative treatment of Achilles tendon tears in the United States from 2005 to 2011 in patients registered with a large Medicare database. Study Design: Descriptive epidemiological study. Methods: Patients who underwent nonoperative and operative treatment of Achilles tendon ruptures by either primary repair or primary repair with graft (International Classification of Diseases 9 [ICD-9] diagnosis code 727.67, Current Procedural Terminology [CPT] codes 27650 and 27652) for the years 2005 to 2011 were identified using the PearlDiver Medicare Database. Demographic and utilization data available within the database were extracted for patients who underwent nonoperative as well as operative treatment for Achilles tendon ruptures. Statistical analysis involved Student t tests, chi-square tests, and linear regression analyses, with statistical significance set at P < .05. Results: From 2005 to 2011, there were a total of 14,127 Achilles tendon ruptures. Of these, 9814 were managed nonoperatively, 3531 were treated with primary repair, and 782 were treated with primary repair with graft. The incidence of Achilles tendon increased from 0.67 per 10,000 in 2005 to 1.08 per 10,000 in 2011 (P < .01). There was no significant difference in the number of Achilles ruptures between males (6636) and females (7582) (P > .05). There was an increase in the overall number of Achilles tendon ruptures over time (1689 in 2005 compared with 2788 in 2011; P < .001) but no difference in the percentage of Achilles ruptures treated operatively (P > .05). Older patients were more likely to be treated nonoperatively (P < .05). No differences in operative versus nonoperative treatment were seen between yearly quarter (P > .05), sex (P > .05), or region (P > .05). Conclusion: The incidence of Achilles tendon ruptures is increasing with time, but the trend in operative and nonoperative treatment has not changed between 2005 and 2011. Older patients, especially those older than 85 years, are more likely to be treated nonoperatively. No differences in treatment patterns were seen based on sex, region, or yearly quarter. PMID:26535361

  19. Dural tear of unusual cause

    PubMed Central

    Kechna, Hicham; Loutid, Jaouad; Ouzzad, Omar; Hanafi, Sidi Mohamed; Hachimi, Moulay Ahmed

    2015-01-01

    Epidural analgesia is highly recommended in cancer anorectal surgery. In addition to the fight against pain it provides some benefit in allowing early rehabilitation of patients. One of the risks of this practice is the dural tear creating a cerebrospinal fluid leak (CSF) in the epidural space (EPD). Clinical features the typical positional headache, a procession of various more or less severe symptoms: nausea, vomiting, dizziness, visual or hearing impairment or radicular pain. We report a dural of unusual cause secondary of the obstruction of tuohy catheter by vertebral cartilage. PMID:26113920

  20. Informing tendon tissue engineering with embryonic development

    PubMed Central

    Glass, Zachary A.; Schiele, Nathan R.; Kuo, Catherine K.

    2014-01-01

    Tendon is a strong connective tissue that transduces muscle-generated forces into skeletal motion. In fulfilling this role, tendons are subjected to repeated mechanical loading and high stress, which may result in injury. Tissue engineering with stem cells offers the potential to replace injured/damaged tissue with healthy, new living tissue. Critical to tendon tissue engineering is the induction and guidance of stem cells towards the tendon phenotype. Typical strategies have relied on adult tissue homeostatic and healing factors to influence stem cell differentiation, but have yet to achieve tissue regeneration. A novel paradigm is to use embryonic developmental factors as cues to promote tendon regeneration. Embryonic tendon progenitor cell differentiation in vivo is regulated by a combination of mechanical and chemical factors. We propose that these cues will guide stem cells to recapitulate critical aspects of tenogenesis and effectively direct the cells to differentiate and regenerate new tendon. Here, we review recent efforts to identify mechanical and chemical factors of embryonic tendon development to guide stem/progenitor cell differentiation toward new tendon formation, and discuss the role this work may have in the future of tendon tissue engineering. PMID:24484642

  1. Patch-Augmented Latissimus Dorsi Transfer and Open Reduction–Internal Fixation of Unstable Os Acromiale for Irreparable Massive Posterosuperior Rotator Cuff Tear

    PubMed Central

    Petri, Maximilian; Greenspoon, Joshua A.; Bhatia, Sanjeev; Millett, Peter J.

    2015-01-01

    Latissimus dorsi transfer is a reasonable treatment option for massive posterosuperior rotator cuff tears that can substantially improve chronically painful and dysfunctional shoulders. This report and accompanying video describe the treatment of an active 43-year-old man with severe pain and weakness in the right shoulder after 3 failed rotator cuff repairs. Preoperative imaging showed a massive posterosuperior rotator cuff tear retracted to the glenoid as well as a hypermobile os acromiale likely causing dynamic impingement and recurrent rotator cuff tears. After diagnostic arthroscopy, the latissimus tendon is harvested and augmented with a 3-mm human acellular dermal patch (ArthroFlex; Arthrex, Naples, FL). The native rotator cuff tissue is repaired as much as possible, and the latissimus tendon is passed underneath the deltoid and posterior to the teres minor. The patch-augmented tendon is then integrated into a double-row SpeedBridge repair of eight 4.75-mm BioComposite SwiveLock anchors (Arthrex). The bony surface of the os acromiale is prepared and then fixed to the acromion with 2 cannulated partially threaded screws and additional tension-band wiring. Postoperative rehabilitation initially focuses on early passive range of motion, followed by active and active-assisted motion and a biofeedback program starting at 6 weeks postoperatively. PMID:26697309

  2. Role of biomechanics in the understanding of normal, injured, and healing ligaments and tendons

    PubMed Central

    Jung, Ho-Joong; Fisher, Matthew B; Woo, Savio L-Y

    2009-01-01

    Ligaments and tendons are soft connective tissues which serve essential roles for biomechanical function of the musculoskeletal system by stabilizing and guiding the motion of diarthrodial joints. Nevertheless, these tissues are frequently injured due to repetition and overuse as well as quick cutting motions that involve acceleration and deceleration. These injuries often upset this balance between mobility and stability of the joint which causes damage to other soft tissues manifested as pain and other morbidity, such as osteoarthritis. The healing of ligament and tendon injuries varies from tissue to tissue. Tendinopathies are ubiquitous and can take up to 12 months for the pain to subside before one could return to normal activity. A ruptured medial collateral ligament (MCL) can generally heal spontaneously; however, its remodeling process takes years and its biomechanical properties remain inferior when compared to the normal MCL. It is also known that a midsubstance anterior cruciate ligament (ACL) tear has limited healing capability, and reconstruction by soft tissue grafts has been regularly performed to regain knee function. However, long term follow-up studies have revealed that 20–25% of patients experience unsatisfactory results. Thus, a better understanding of the function of ligaments and tendons, together with knowledge on their healing potential, may help investigators to develop novel strategies to accelerate and improve the healing process of ligaments and tendons. With thousands of new papers published in the last ten years that involve biomechanics of ligaments and tendons, there is an increasing appreciation of this subject area. Such attention has positively impacted clinical practice. On the other hand, biomechanical data are complex in nature, and there is a danger of misinterpreting them. Thus, in these review, we will provide the readers with a brief overview of ligaments and tendons and refer them to appropriate methodologies used to obtain their biomechanical properties. Specifically, we hope the reader will pay attention to how the properties of these tissues can be altered due to various experimental and biologic factors. Following this background material, we will present how biomechanics can be applied to gain an understanding of the mechanisms as well as clinical management of various ligament and tendon ailments. To conclude, new technology, including imaging and robotics as well as functional tissue engineering, that could form novel treatment strategies to enhance healing of ligament and tendon are presented. PMID:19457264

  3. Active Achilles tendon kinesitherapy accelerates Achilles tendon repair by promoting neurite regeneration?

    PubMed Central

    Jielile, Jiasharete; Aibai, Minawa; Sabirhazi, Gulnur; Shawutali, Nuerai; Tangkejie, Wulanbai; Badelhan, Aynaz; Nuerduola, Yeermike; Satewalede, Turde; Buranbai, Darehan; Hunapia, Beicen; Jialihasi, Ayidaer; Bai, Jingping; Kizaibek, Murat

    2012-01-01

    Active Achilles tendon kinesitherapy facilitates the functional recovery of a ruptured Achilles tendon. However, protein expression during the healing process remains a controversial issue. New Zealand rabbits, aged 14 weeks, underwent tenotomy followed immediately by Achilles tendon microsurgery to repair the Achilles tendon rupture. The tendon was then immobilized or subjected to postoperative early motion treatment (kinesitherapy). Mass spectrography results showed that after 14 days of motion treatment, 18 protein spots were differentially expressed, among which, 12 were up-regulated, consisting of gelsolin isoform b and neurite growth-related protein collapsing response mediator protein 2. Western blot analysis showed that gelsolin isoform b was up-regulated at days 7–21 of motion treatment. These findings suggest that active Achilles tendon kinesitherapy promotes the neurite regeneration of a ruptured Achilles tendon and gelsolin isoform b can be used as a biomarker for Achilles tendon healing after kinesitherapy. PMID:25317130

  4. Subchondral mineralization patterns of the glenoid after tear of the supraspinatus.

    PubMed

    Anetzberger, H; Schulz, C; Pfahler, M; Refior, H J; Müller-Gerbl, M

    2002-11-01

    Clinical experience has shown that in many cases of rupture of the supraspinatus tendon the head of the humerus shifts upward against the acromion. This implicates alterations in the stress acting on the joint surface. Accordingly, this should be reflected by changes in the distribution of the subchondral mineralization on the glenoid. Computed tomography osteoabsorptiometry was used to evaluate the distribution patterns on the subchondral bone plate of the glenoid in 67 human shoulders. The position of the two most frequent density maxima was determined by a standard procedure. In macroscopically normal specimens (n = 24) every case had an anterosuperior density maximum and the majority (75%) also had a posterior positioned maximum. In some instances a third maximum, placed centrally (17%) or in an anteroinferior position (4%) was seen. In shoulders with a torn supraspinatus tendon (n = 43) a third density maximum frequently appeared in the center of the glenoid (42%); however, most notable was a significant change of the posterior maximum position toward central and superior. With increasing size of the tendon defect an extension of the shift of the posterior maximum (superiorly and centrally) was observed in contrast to the constant anterior maximum. The changes in the distribution of glenoid subchondral bone mineralization in shoulders with a supraspinatus tear must be regarded as a morphologic parameter for the altered long-term stress acting on the joint surface. PMID:12439268

  5. Nutrient pathways of flexor tendons in primates

    SciTech Connect

    Manske, P.R.; Lesker, P.A.

    1982-09-01

    The perfusion and diffusion pathways to the flexor profundus tendons of 40 monkeys were investigated by measuring the uptake of tritiated proline by various tendon segments. In the absence of all vascular connections, the process of diffusion provides nutrients to all areas of flexor tendon and in this study the process of diffusion was greater. The distal segment of tendon was observed to be profused most rapidly. The proximal tendon segment is perfused from both the muscular-tendinous junction and the vinculum longus; vincular segment perfusion is via the vinculum longus vessels alone; central segment perfusion is shared by the vinculum longus and vinculum brevis vasculature. The distal segment uptake is by both the process of diffusion or vinculum brevis perfusion. The osseous attachment at the distal phalanx contributes little to tendon nutrition.

  6. Lacritin, a Novel Human Tear Glycoprotein, Promotes Sustained Basal Tearing and Is Well Tolerated

    PubMed Central

    Lattanzio, Frank A.; Lossen, Victoria; Hosseini, Alireza; Sheppard, John D.; McKown, Robert L.; Laurie, Gordon W.; Williams, Patricia B.

    2011-01-01

    Purpose. Lacritin is a novel human tear glycoprotein that promotes basal tear peroxidase secretion by rat lacrimal acinar cells in vitro. This study investigates whether lacritin is prosecretory when added topically to the ocular surface of normal living rabbits, and if so, what is its efficacy and tolerability versus cyclosporine and artificial tears. Methods. Purified recombinant human lacritin (1, 10, 50, or 100 ?g/mL), inactive lacritin truncation mutant C-25 (10 ?g/mL), cyclosporine (0.05%), or artificial tears were topically administered to eyes of normal New Zealand White rabbits either as a single dose or three times daily for 14 days with monitoring of basal tear production. Basal tearing under proparacaine anesthesia was repeatedly assessed throughout and 1 week after chronic treatment ceased. Eyes were examined weekly by slit-lamp biomicroscopy. Results. Lacritin acutely increased basal tearing to 30% over vehicle at 240 minutes. Three times daily treatment with 10–100 ?g/mL lacritin was well tolerated. Basal tearing became progressively elevated 4, 7, and 14 days later and was 50% over baseline (50 ?g/mL lacritin) 1 week after treatment had ceased. Cyclosporine elevated tearing to a similar level on days 4 and 7 but had little or no effect on day 14 and had returned to baseline 1 week after ending treatment. C-25 and artificial tears had no effect. Conclusions. Lacritin acutely stimulates basal tear flow that is sustained for at least 240 minutes. Two weeks of lacritin treatment three times daily was well tolerated and progressively elevated the basal tear flow. One week after treatment ended, basal tearing was still 50% over baseline. In contrast, cyclosporine triggered mild to moderate corneal irritation and a temporary elevation in tearing. PMID:21087963

  7. The Effects of Hemodialysis on Tear Osmolarity

    PubMed Central

    Taskapili, Muhittin; Serefoglu Cabuk, Kubra; Aydin, Rukiye; Atalay, Kursat; Kirgiz, Ahmet; Sit, Dede; Kayabasi, Hasan

    2015-01-01

    Aim. To determine the effects of hemodialysis (HD) on tear osmolarity and to define the blood biochemical tests correlating with tear osmolarity among patients with end stage renal disease (ESRD). Material-Method. Tear osmolarity of ESRD patients before and after the hemodialysis program was determined as well as the blood biochemical data including glucose, sodium, potassium, calcium, urea, and creatinine levels. Results. Totally 43 eyes of 43 patients (20 females and 23 males) with a mean age of 53.98 ± 18.06 years were included in the study. Tear osmolarity of patients was statistically significantly decreased after hemodialysis (314.06 ± 17.77 versus 301.88 ± 15.22?mOsm/L, p = 0.0001). In correlation analysis, pre-HD tear osmolarity was negatively correlated with pre-HD blood creatinine level (r = ?0.366,??p = 0.016). Post-HD tear osmolarity was statistically significantly correlated with the post-HD glucose levels (r = 0.305??p = 0.047). Tear osmolarity alteration by HD was negatively correlated with creatinine alteration, body weight alteration, and ultrafiltration (r = ?0.426,??p = 0.004; r = ?0.365,??p = 0.016; and r = ?0.320, p = 0.036, resp.). There was no correlation between tear osmolarity and Kt/V and URR values. Conclusion. HD effectively decreases tear osmolarity to normal values and corrects the volume and composition of the ocular fluid transiently. Tear osmolarity alteration induced by HD is correlated with body weight changes, creatinine alterations, and ultrafiltration. PMID:26640702

  8. [Effects of Gravity on Attachment of Tendon to Bone

    NASA Technical Reports Server (NTRS)

    Johnson, Roger B.

    1997-01-01

    We have received and processed all samples for either light or scanning electron microscopic analysis and have completed the histomorphometric analysis. We have characterized the changes caused by spaceflight to tendon attachments to the calcaneus, tibia, fibula and femur and compared them to hindlimbs and forelimbs from NIH.RZ. Soleus muscle histomorphometry has also been completed. Our results suggest severe osteoporosis in the femur, fibula and tibia of animals coincident to spaceflight, which had not resolved after 4-5 days following return to earth. This was evident at all sites, including sites of tendon attachments. This atrophy was not evident in the calcaneus. No muscle atrophy was evident. Comparison of scanning photomicrographs of flight animals with other lactating animals demonstrated structural similarities and suggested that it might be worthwhile to assess whether lactation is a factor in development of the osteoporosis in the spaceflight animals. In addition, evaluation of total calcium utilization by spaceflight animals would be beneficial.

  9. Achilles tendon rupture in badminton.

    PubMed Central

    Kaalund, S; Lass, P; Høgsaa, B; Nøhr, M

    1989-01-01

    The typical badminton player with an Achilles tendon rupture is 36 years old and, despite limbering up, is injured at the rear line in a sudden forward movement. He resumes work within three months and has a slight lack of dorsiflexion in the ankle as the main complication. Most patients resume badminton within one year, but some finish their sports career, mainly due to fear of a new injury. The investigation discusses predisposing factors and prophylactic measures. PMID:2605439

  10. Tendon sheath fibroma in the thigh.

    PubMed

    Moretti, Vincent M; Ashana, Adedayo O; de la Cruz, Michael; Lackman, Richard D

    2012-04-01

    Tendon sheath fibromas are rare, benign soft tissue tumors that are predominantly found in the fingers, hands, and wrists of young adult men. This article describes a tendon sheath fibroma that developed in the thigh of a 70-year-old man, the only known tendon sheath fibroma to form in this location. Similar to tendon sheath fibromas that develop elsewhere, our patient's lesion presented as a painless, slow-growing soft tissue nodule. Physical examination revealed a firm, nontender mass with no other associated signs or symptoms. Although the imaging appearance of tendon sheath fibromas varies, our patient's lesion appeared dark on T1- and bright on T2-weighted magnetic resonance imaging. It was well marginated and enhanced with contrast.Histologically, tendon sheath fibromas are composed of dense fibrocollagenous stromas with scattered spindle-shaped fibroblasts and narrow slit-like vascular spaces. Most tendon sheath fibromas can be successfully removed by marginal excision, although 24% of lesions recur. No lesions have metastasized. Our patient's tendon sheath fibroma was removed by marginal excision, and the patient remained disease free 35 months postoperatively. Despite its rarity, tendon sheath fibroma should be included in the differential diagnosis of a thigh mass on physical examination or imaging, especially if it is painless, nontender, benign appearing, and present in men. PMID:22495871

  11. Mass Spectrometric Identification of Phospholipids in Human Tears and Tear Lipocalin

    PubMed Central

    Dean, Austin W.; Glasgow, Ben J.

    2012-01-01

    Purpose. The purpose of this article was to identify by mass spectrometry phosphocholine lipids in stimulated human tears and determine the molecules bound to tear lipocalin or other proteins. Methods. Tear proteins were separated isocratically from pooled stimulated human tears by gel filtration fast performance liquid chromatography. Separation of tear lipocalin was confirmed by SDS tricine gradient PAGE. Protein fractions were extracted with chloroform/methanol and analyzed with electrospray ionization MS/MS triple quadrupole mass spectrometry in precursor ion scan mode for select leaving groups. For quantification, integrated ion counts were derived from standard curves of authentic compounds of phosphatidylcholine (PC) and phosphatidylserine. Results. Linear approximation was possible from integration of the mass spectrometrically obtained ion peaks at 760 Da for the PC standard. Tears contained 194 ng/mL of the major intact PC (34:2), m/z 758.6. Ten other monoisotopic phosphocholines were found in tears. A peak at 703.3 Da was assigned as a sphingomyelin. Four lysophosphatidylcholines (m/z 490–540) accounted for about 80% of the total integrated ion count. The [M+H]+ compound, m/z 496.3, accounted for 60% of the signal intensity. Only the tear lipocalin–bearing fractions showed phosphocholines (104 ng/mL). Although the intact phospholipids bound to tear lipocalin corresponded precisely in mass and relative signal intensity to that found in tears, we did not identify phosphocholines between m/z 490 and 540 in any of the gel-filtration fractions. Conclusions. Phospholipids, predominantly lysophospholipids, are present in tears. The higher mass intact PCs in tears are native ligands of tear lipocalin. PMID:22395887

  12. Anatomic Reconstruction of Chronic Coracoclavicular Ligament Tears: Arthroscopic-Assisted Approach With Nonrigid Mechanical Fixation and Graft Augmentation

    PubMed Central

    Natera, Luis; Sarasquete Reiriz, Juan; Abat, Ferran

    2014-01-01

    It has recently been suggested that all coracoclavicular ligament tears could be considered for surgery because nonoperative management might result in irreversible changes in the scapular position that could lead to muscle kinematic alterations that would perturb the shoulder girdle function and result in pain. In this technical note we describe an anatomic technique for the treatment of chronic coracoclavicular ligament tears that overcomes the issues related to open surgery, metal hardware, the inferior resistance to secondary displacement of only grafting and nonanatomic techniques, and the saw effect and anterior loop translation that can be seen in systems that surround the base of the coracoid. Our technique incorporates the use of a tendon graft and a nonrigid mechanical stabilizer that protects the graft from stretching during the process of healing and integration into bone, guaranteeing the maintenance of a reduced acromioclavicular joint. PMID:25473611

  13. Polyimide Film of Increased Tear Strength

    NASA Technical Reports Server (NTRS)

    St. Clair, A. K.; Hinkley, J. A.; Ezzell, S. A.

    1986-01-01

    High-temperature linear aromatic polyimide with improved resistance to tearing made by new process that incorporates elastomer into polyimide. Linear aromatic condensation polyimides are materials of prime choice for use as films and coatings on advanced spacecraft and aircraft where durability at temperatures in range of 200 to 300 degree C required. Elastomer-containing polyimide film with improved toughness proves useful for applications where resistance to tearing and long-term thermal stability necessary. Desired resistance to tearing achieved by careful control of amount and chemical composition of added elastomer.

  14. Systematic Review: What Surgical Technique Provides the Best Outcome for Symptomatic Partial Articular-Sided Rotator Cuff Tears?

    PubMed Central

    Bollier, Matthew; Shea, Kevin

    2012-01-01

    Purpose There is no consensus in the literature regarding the optimal surgical treatment of symptomatic partial rotator cuff tears. We attempted to determine the optimal surgical treatment for partial articular-sided rotator cuff tears through a systematic review of appropriate studies. Methods Medline®, PubMed, Ovid, and the cochrane register of controlled trials were searched for all studies published between January 1991 to March 2010 that used the key words “shoulder”, “partial rotator cuff tear”, “PASTA”, “articularsided rotator cuff tear”, “incomplete rotator cuff tear”, “arthroscopic” and “repair”. Inclusion criteria were studies (Level I to IV) that reported clinical outcomes in patients who had arthroscopic evaluation and arthroscopic or mini-open treatment of a symptomatic partial articular-sided rotator cuff tear. One of three surgical treatments was used: debridement with or without acromioplasty; transtendon arthroscopic repair; or tear completion with repair. Exclusion criteria included studies with over 50% overhead throwers or athletes, studies that involved an open approach to the rotator cuff without arthroscopy, and data presented in technical notes or review papers. Data abstracted from the studies included patient demographics, tear characteristics, surgical procedure(s), and clinical outcomes. Results Of 588 studies involving partial rotator cuff tears, 14 studies were identified which met our inclusion and exclusion criteria. All studies were Level IV retrospective case-series studies. Seven studies reported outcomes after rotator cuff debridement. Tear completion and repair was performed in three studies. Transtendon repair of a partial articular-sided rotator cuff tear was performed in three studies. Although different outcome measures were used, each study reported subjective and objective improvement postoperatively. One study compared outcomes in patients who underwent arthroscopic debridement versus another group where patients had tear completion and mini-open repair. Improved long-term results and decreased reoperation rates were reported in the tear completion and repair group. Conclusion On the basis of the available evidence, no single technique provides superior clinical outcomes. Level I and II comparison studies are needed to determine the optimal treatment of partial articular-sided rotator cuff tears. PMID:23576937

  15. Tear Movement through a Contact Lens of Variable Thickness

    NASA Astrophysics Data System (ADS)

    Gerhart, Matthew; Anderson, Daniel

    2013-11-01

    This work is on a two-dimensional tear film with a movable porous contact lens. The inclusion of a contact lens into a tear film results in three layers: Pre-Lens Tear Film, Contact Lens, and the Post-Lens Tear Film layers. The interfaces between the contact lens and the tear films are modeled as planar interfaces. There is a free surface interface between the tear film and the outside air. The goal is analyze the effects of the spatial variability of thickness on the Post-Lens Tear Film thickness and on the fluid flow through the Contact Lens layer.

  16. Structure-mechanics relationships in mineralized tendons.

    PubMed

    Spiesz, Ewa M; Zysset, Philippe K

    2015-12-01

    In this paper, we review the hierarchical structure and the resulting elastic properties of mineralized tendons as obtained by various multiscale experimental and computational methods spanning from nano- to macroscale. The mechanical properties of mineralized collagen fibres are important to understand the mechanics of hard tissues constituted by complex arrangements of these fibres, like in human lamellar bone. The uniaxial mineralized collagen fibre array naturally occurring in avian tendons is a well studied model tissue for investigating various stages of tissue mineralization and the corresponding elastic properties. Some avian tendons mineralize with maturation, which results in a graded structure containing two zones of distinct morphology, circumferential and interstitial. These zones exhibit different amounts of mineral, collagen, pores and a different mineral distribution between collagen fibrillar and extrafibrillar space that lead to distinct elastic properties. Mineralized tendon cells have two phenotypes: elongated tenocytes placed between fibres in the circumferential zone and cuboidal cells with lower aspect ratios in the interstitial zone. Interestingly some regions of avian tendons seem to be predestined to mineralization, which is exhibited as specific collagen cross-linking patterns as well as distribution of minor tendon constituents (like proteoglycans) and loss of collagen crimp. Results of investigations in naturally mineralizing avian tendons may be useful in understanding the pathological mineralization occurring in some human tendons. PMID:25922092

  17. Jumper's Knee (Patellar Tendonitis) (For Parents)

    MedlinePLUS

    ... includes removing the damaged portion of the patellar tendon, removing inflammatory tissue from the lower area (or bottom pole) of the patella, or making small cuts on the sides of the patellar tendon to relieve pressure from the middle area. After ...

  18. The pathology of flexor tendon repair.

    PubMed

    Matthews, P

    1979-10-01

    This paper discusses the problems of failure after tendon repair. For a long time the subject has been dominated by the problem of adhesion formation. Recent work has shown that this is not inevitable, and consideration of other factors, particularly the nutrition of tendon tissue is leading to the possibilities of other methods of treatment. PMID:520866

  19. The Mechanical Properties of Rat Tail Tendon

    PubMed Central

    Rigby, Bernard J.; Hirai, Nishio; Spikes, John D.; Eyring, Henry

    1959-01-01

    The load-strain and stress-relaxation behavior of wet rat tail tendon has been examined with respect to the parameters strain, rate of straining, and temperature. It is found that this mechanical behavior is reproducible after resting the tendon for a few minutes after each extension so long as the strain does not exceed about 4 per cent. If this strain is exceeded, the tendon becomes progressively easier to extend but its length still returns to the original value after each extension. Extensions of over 35 per cent can be reached in this way. Temperature has no effect upon the mechanical behavior over the range 0–37°C. Just above this temperature, important changes take place in the mechanical properties of the tendon which may have biological significance. The application of the techniques used here to studies of connective tissue disorders is suggested. Some of the mechanical properties of tendon have been interpreted with a simple model. PMID:19873525

  20. Tendon Vasculature in Health and Disease

    PubMed Central

    Tempfer, Herbert; Traweger, Andreas

    2015-01-01

    Tendons represent a bradytrophic tissue which is poorly vascularized and, compared to bone or skin, heal poorly. Usually, a vascularized connective scar tissue with inferior functional properties forms at the injury site. Whether the increased vascularization is the root cause of tissue impairments such as loss of collagen fiber orientation, ectopic formation of bone, fat or cartilage, or is a consequence of these pathological changes remains unclear. This review provides an overview of the role of tendon vasculature in healthy and chronically diseased tendon tissue as well as its relevance for tendon repair. Further, the nature and the role of perivascular tendon stem/progenitor cells residing in the vascular niche will be discussed and compared to multipotent stromal cells in other tissues. PMID:26635616

  1. Rotator Cuff Tears: Surgical Treatment Options

    MedlinePLUS

    ... Large or massive tears • Poor patient compliance with rehabilitation and restrictions a er surgery • Patient age (older than 65 years) • Smoking and use of other nicotine products • Workers’ compensation ...

  2. On the tear resistance of skin

    PubMed Central

    Yang, Wen; Sherman, Vincent R.; Gludovatz, Bernd; Schaible, Eric; Stewart, Polite; Ritchie, Robert O.; Meyers, Marc A.

    2015-01-01

    Tear resistance is of vital importance in the various functions of skin, especially protection from predatorial attack. Here, we mechanistically quantify the extreme tear resistance of skin and identify the underlying structural features, which lead to its sophisticated failure mechanisms. We explain why it is virtually impossible to propagate a tear in rabbit skin, chosen as a model material for the dermis of vertebrates. We express the deformation in terms of four mechanisms of collagen fibril activity in skin under tensile loading that virtually eliminate the possibility of tearing in pre-notched samples: fibril straightening, fibril reorientation towards the tensile direction, elastic stretching and interfibrillar sliding, all of which contribute to the redistribution of the stresses at the notch tip. PMID:25812485

  3. Examination of the Biceps Tendon.

    PubMed

    McFarland, Edward G; Borade, Amrut

    2016-01-01

    The examination of the shoulder for conditions involving the biceps tendon continues to be challenging. Numerous examination tests for biceps and superior labrum anterior and posterior (SLAP) lesions have been scientifically evaluated. This section reports on how to perform these tests and summarizes the clinical utility of the tests. Many of the tests for the examination of the biceps and for SLAP lesions do not have high sensitivity and specificity, which limits their usefulness. Although the dynamic shear test has promise for making the diagnosis of SLAP lesions, the studies reporting its clinical utility are disparate. PMID:26614467

  4. Cup arthroplasty for rotator cuff tear arthropathy.

    PubMed

    Mariscalco, Michael W; Patterson, Ryan W; Seitz, William H

    2011-03-01

    Cup arthroplasty is a conservative bone-sparing option for resurfacing of the humeral head. Earlier reports have shown its effectiveness in appropriately selected patients with osteoarthritis, osteonecrosis, and severe rheumatoid arthritis. Patients with cuff tear arthropathy may also benefit from a modified cup arthroplasty technique. The purpose of this article is to describe the surgical technique involved in humeral cup arthroplasty in cuff tear arthropathy patients. We will review the indications, contraindications, complications, and postoperative rehabilitation. PMID:21358516

  5. Tear film measurement by optical reflectometry technique.

    PubMed

    Lu, Hui; Wang, Michael R; Wang, Jianhua; Shen, Meixiao

    2014-02-01

    Evaluation of tear film is performed by an optical reflectometer system with alignment guided by a galvanometer scanner. The reflectometer system utilizes optical fibers to deliver illumination light to the tear film and collect the film reflectance as a function of wavelength. Film thickness is determined by best fitting the reflectance-wavelength curve. The spectral reflectance acquisition time is 15 ms, fast enough for detecting film thickness changes. Fast beam alignment of 1 s is achieved by the galvanometer scanner. The reflectometer was first used to evaluate artificial tear film on a model eye with and without a contact lens. The film thickness and thinning rate have been successfully quantified with the minimum measured thickness of about 0.3 ?m. Tear films in human eyes, with and without a contact lens, have also been evaluated. A high-contrast spectral reflectance signal from the precontact lens tear film is clearly observed, and the thinning dynamics have been easily recorded from 3.69 to 1.31 ?m with lipid layer thickness variation in the range of 41 to 67 nm. The accuracy of the measurement is better than ±0.58% of the film thickness at an estimated tear film refractive index error of ±0.001. The fiber-based reflectometer system is compact and easy to handle. PMID:24500519

  6. Is higher serum cholesterol associated with altered tendon structure or tendon pain? A systematic review

    PubMed Central

    Tilley, Benjamin J; Cook, Jill L; Docking, Sean I; Gaida, James E

    2015-01-01

    Background Tendon pain occurs in individuals with extreme cholesterol levels (familial hypercholesterolaemia). It is unclear whether the association with tendon pain is strong with less extreme elevations of cholesterol. Objective To determine whether lipid levels are associated with abnormal tendon structure or the presence of tendon pain. Methods We conducted a systematic review and meta-analysis. Relevant articles were found through an electronic search of 6 medical databases—MEDLINE, Cochrane, AMED, EMBASE, Web of Science and Scopus. We included all case–control or cross-sectional studies with data describing (1) lipid levels or use of lipid-lowering drugs and (2) tendon structure or tendon pain. Results 17 studies (2612 participants) were eligible for inclusion in the review. People with altered tendon structure or tendon pain had significantly higher total cholesterol, low-density lipoprotein cholesterol and triglycerides, as well as lower high-density lipoprotein cholesterol; with mean difference values of 0.66, 1.00, 0.33, and ?0.19 mmol/L, respectively. Conclusions The results of this review indicate that a relationship exists between an individual’s lipid profile and tendon health. However, further longitudinal studies are required to determine whether a cause and effect relationship exists between tendon structure and lipid levels. This could lead to advancement in the understanding of the pathoaetiology and thus treatment of tendinopathy. PMID:26474596

  7. Functional Tissue Engineering of Tendon: Establishing Biological Success Criteria for Improving Tendon Repair

    PubMed Central

    Breidenbach, Andrew P; Gilday, Steven D; Lalley, Andrea L; Dyment, Nathaniel A; Gooch, Cynthia; Shearn, Jason T; Butler, David L

    2013-01-01

    Improving tendon repair using Functional Tissue Engineering (FTE) principles has been the focus of our laboratory over the last decade. Although our primary goals were initially focused only on mechanical outcomes, we are now carefully assessing the biological properties of our tissue-engineered tendon repairs so as to link biological influences with mechanics. However, given the complexities of tendon development and healing, it remains challenging to determine which aspects of tendon biology are the most important to focus on in the context of tissue engineering. To address this problem, we have formalized a strategy to identify, prioritize, and evaluate potential biological success criteria for tendon repair. We have defined numerous biological properties of normal tendon relative to cellular phenotype, extracellular matrix and tissue ultra-structure that we would like to reproduce in our tissue-engineered repairs and prioritized these biological criteria by examining their relative importance during both normal development and natural tendon healing. Here, we propose three specific biological criteria which we believe are essential for normal tendon function: 1) scleraxis-expressing cells; 2) well-organized and axially-aligned collagen fibrils having bimodal diameter distribution; and 3) a specialized tendon-to-bone insertion site. Moving forward, these biological success criteria will be used in conjunction with our already established mechanical success criteria to evaluate the effectiveness of our tissue-engineered tendon repairs. PMID:24200342

  8. BME 315 Biomechanics Material Properties of Tendon: introduction

    E-print Network

    Lakes, Roderic

    properties of a tendon. Tendons and ligaments are very similar in structure and composition. They are both composed of collagen and elastin fibers, with a structural hierarchy (Fig. 1). Structurally, tendons). The material composition and properties of tendons and ligaments reflect the differences in loading

  9. Doppler ultrasound-based measurement of tendon velocity and displacement for application toward detecting user-intended motion.

    PubMed

    Stegman, Kelly J; Park, Edward J; Dechev, Nikolai

    2012-07-01

    The motivation of this research is to non-invasively monitor the wrist tendon's displacement and velocity, for purposes of controlling a prosthetic device. This feasibility study aims to determine if the proposed technique using Doppler ultrasound is able to accurately estimate the tendon's instantaneous velocity and displacement. This study is conducted with a tendon mimicking experiment consisting of two different materials: a commercial ultrasound scanner, and a reference linear motion stage set-up. Audio-based output signals are acquired from the ultrasound scanner, and are processed with our proposed Fourier technique to obtain the tendon's velocity and displacement estimates. We then compare our estimates to an external reference system, and also to the ultrasound scanner's own estimates based on its proprietary software. The proposed tendon motion estimation method has been shown to be repeatable, effective and accurate in comparison to the external reference system, and is generally more accurate than the scanner's own estimates. After establishing this feasibility study, future testing will include cadaver-based studies to test the technique on the human arm tendon anatomy, and later on live human test subjects in order to further refine the proposed method for the novel purpose of detecting user-intended tendon motion for controlling wearable prosthetic devices. PMID:22913101

  10. Catastrophic Failure of an Infected Achilles Tendon Rupture Repair Managed with Combined Flexor Hallucis Longus and Peroneus Brevis Tendon Transfer.

    PubMed

    Simonson, Devin C; Elliott, Andrew D; Roukis, Thomas S

    2016-01-01

    Deep infection is one of the most devastating complications following repair of an Achilles tendon rupture. Treatment requires not only culture-driven antibiotic therapy, but more importantly, appropriate débridement of some or even all of the Achilles tendon. This may necessitate delayed reconstruction of the Achilles tendon. The authors present a successful case of reconstruction of a chronically infected Achilles tendon in an otherwise healthy 43-year-old man via a multistaged approach using the flexor hallucis longus and peroneus brevis tendons. We also provide a brief review of the literature regarding local tendon transfer used in the reconstruction of Achilles tendon rupture. PMID:26590732

  11. Arthroscopy-assisted anterior cruciate ligament reconstruction with patellar tendon or hamstring autografts.

    PubMed

    Doral, M N; Leblebicioglu, G; Atay, O A; Baydar, M L; Tetik, O; Atik, S

    2000-01-01

    Isolated ACL reconstructions were performed in 138 patients between 1994 and 1998. Patellar bone-patellar tendon-bone, and hamstring tendon autografts were used in 88 patients, and allografts were used in 50 patients. Eighty-eight knees of 88 patients with autograft reconstructions (17 female, 71 male) were included in this study and evaluation of the patients with allograft reconstruction reported separately. The mean age at the time of the operation was 32 years. All ACL reconstructions were performed arthroscopically. Twenty-seven bone-patellar tendon-bone, and 61 hamstring tendon autografts were used. The mean follow-up was 29 months. In the postoperative course the Lachman test was negative in 62 patients, 1+ in 22 patients, and 2+ in 4 patients. In 17 patients, anterior drawer sign were 1+ in comparison to the contralateral side. Pivot shift test was moderately positive only in 5 cases in the bone-patellar tendon-bone and hamstring tendon autograft groups postoperatively. There were 3 patients with subjective "giving way" symptoms. Second look arthroscopy revealed rupture of the neo-ligament. Arthroscopic washout and debridement were performed, and no revision ligamentoplasties were performed. Two of these patients improved with accelerated proprioceptive physical therapy, and one had to decrease his previous level of activity. There were no cases of arthrofibrosis, infection, or extension lag. Clinical results of patellar bone-tendon-bone and hamstring groups did not show any significant clinical difference. Avoiding the disturbance of the extensor mechanism of the knee is probably the most significant advantage of the hamstring autograft. PMID:10983256

  12. Tendon and Ligament Regeneration and Repair: Clinical Relevance and Developmental Paradigm

    PubMed Central

    Tuan, Rocky S.

    2014-01-01

    Tendon and ligament (T/L) are dense connective tissues connecting bone to muscle and bone to bone, respectively. Similar to other musculoskeletal tissues, T/L arise from the somitic mesoderm, but they are derived from a recently discovered somitic compartment, the syndetome. The adjacent sclerotome and myotome provide inductive signals to the interposing syndetome, thereby upregulating the expression of the transcription factor Scleraxis, which in turn leads to further tenogenic and ligamentogenic differentiation. These advances in the understanding of T/L development have been sought to provide a knowledge base for improving the healing of T/L injuries, a common clinical challenge due to the intrinsically poor natural healing response. Specifically, the three most common tendon injuries involve tearing of the rotator cuff of the shoulder, the flexor tendon of the hand, and the Achilles tendon. At present, injuries to these tissues are treated by surgical repair and/or conservative approaches, including biophysical modalities such as physical rehabilitation and cryotherapy. Unfortunately, the healing tissue forms fibrovascular scar and possesses inferior mechanical and biochemical properties as compared to native T/L. Therefore, tissue engineers have sought to improve upon the natural healing response by augmenting the injured tissue with cells, scaffolds, bioactive agents, and mechanical stimulation. These strategies show promise, both in vitro and in vivo, for improving T/L healing. However, several challenges remain in restoring full T/L function following injury, including uncertainties over the optimal combination of these biological agents as well how to best deliver tissue engineered elements to the injury site. A greater understanding of the molecular mechanisms involved in T/L development and natural healing, coupled with the capability of producing complex biomaterials to deliver multiple growth factors with high spatiotemporal resolution and specificity, will allow tissue engineers to more closely recapitulate T/L morphogenesis, thereby offering future patients the prospect of T/L regeneration, as opposed to simple tissue repair. PMID:24078497

  13. Three-dimensional study of pectoralis major muscle and tendon architecture.

    PubMed

    Fung, Lillia; Wong, Brian; Ravichandiran, Kajeandra; Agur, Anne; Rindlisbacher, Tim; Elmaraghy, Amr

    2009-05-01

    A thorough understanding of the normal structural anatomy of the pectoralis major (PM) is of paramount importance in the planning of PM tendon transfers or repairs following traumatic PM tears. However, there is little consensus regarding the complex musculotendinous architecture of the PM in the anatomic or surgical literature. The purpose of this study is to model and quantify the three-dimensional architecture of the pectoralis muscle and tendon. Eleven formalin embalmed cadaveric specimens were examined: five (2M/3F) were serially dissected, digitized, and modeled in 3D using Autodesk Maya; six (4M/2F) were dissected and photographed. The PM tendon consisted of longer anterior and shorter posterior layers that were continuous inferiorly. The muscle belly consisted of an architecturally uniform clavicular head (CH) and a segmented sternal head (SH) with 6-7 segments. The most inferior SH segment in all specimens was found to fold anteriorly forming a trough that cradled the inferior aspect of the adjacent superior segment. No twisting of either the PM muscle or tendon was noted. Within the CH, the fiber bundle lengths (FBL) were found to increase from superior to inferior, whereas the mean FBLs of SH were greatest in segments 3-5 found centrally. The mean lateral pennation angle was greater in the CH (29.4 +/- 6.9 degrees ) than in the SH (20.6 +/- 2.7 degrees ). The application of these findings could form the basis of future studies to optimize surgical planning and functional recovery of repair/reconstruction procedures. PMID:19291757

  14. Principles and Biomechanical Considerations of Tendon Transfers.

    PubMed

    Walton, Laura; Villani, Matthew F

    2016-01-01

    Whether performed as a primary procedure or used to augment and support osseous reconstruction, tendon transfers are a key skill for the foot and ankle surgeon. Understanding the biomechanics preoperative and postoperatively is essential in performing appropriate procedures and in supporting patients through the rehabilitation process. Often the complexity of tendon transfer surgery is lost because it is deemed a soft tissue procedure and in theory should be less complex than osseous procedures. However, the dynamic nature of musculature and tendons require a deeper understanding of surgical and biomechanical concepts. PMID:26590719

  15. Influence of running shoes and cross-trainers on Achilles tendon forces during running compared with military boots.

    PubMed

    Sinclair, Jonathan; Taylor, P J; Atkins, S

    2015-06-01

    Military recruits are known to be susceptible to Achilles tendon pathology. The British Army have introduced footwear models, the PT-03 (cross-trainer) and PT1000 (running shoes), in an attempt to reduce the incidence of injuries. The aim of the current investigation was to examine the Achilles tendon forces of the cross-trainer and running shoe in relation to conventional army boots. Ten male participants ran at 4.0?m/s in each footwear condition. Achilles tendon forces were obtained throughout the stance phase of running and compared using repeated-measures ANOVAs. The results showed that the time to peak Achilles tendon force was significantly shorter when running in conventional army boots (0.12?s) in comparison with the cross-trainer (0.13?s) and running shoe (0.13?s). Achilles tendon loading rate was shown to be significantly greater in conventional army boots (38.73?BW/s) in comparison with the cross-trainer (35.14?BW/s) and running shoe (33.57?BW/s). The results of this study suggest that the running shoes and cross-trainer footwear are associated with reductions in Achilles tendon parameters that have been linked to the aetiology of injury, and thus it can be hypothesised that these footwear could be beneficial for military recruits undertaking running exercises. PMID:25428136

  16. Relationship between clinical and surgical findings and reparability of large and massive rotator cuff tears: a longitudinal study

    PubMed Central

    2014-01-01

    Background The literature has shown good results with partial repairs of large and massive tears of rotator cuff but the role of factors that affect reparability is less clear. The purpose of this study was twofold, 1) to examine clinical outcomes following complete or partial repair of large or massive full-thickness rotator cuff tear, and 2) to explore the value of clinical and surgical factors in predicting reparability. Methods This was a secondary data analysis of consecutive patients with large or massive rotator cuff tear who required surgical treatment (arthroscopic complete or partial repair) and were followed up for two years. Disability measures included the American Shoulder and Elbow Surgeons (ASES), the relative Constant-Murley score (CMS) and the shortened version of the Western Ontario Rotator Cuff Index (ShortWORC). The relationship between predictors and reparability was examined through logistic regressions and chi-square statistics as appropriate. Within group change over time and between group differences in disability outcomes, range of motion and strength were examined by student’s T-tests and non-parametric statistics. Results One hundred and twenty two patients (41 women, 81 men, mean age 64, SD?=?9) were included in the analysis. There were 86 large (39 fully reparable, 47 partially reparable) and 36 (10 fully reparable, 26 partially reparable) massive tears. Reparability was not associated with age, sex, or pre-operative active flexion or abduction (p?>?0.05) but the fully reparable tear group showed a better pre-operative ASES score (p?=?0.01) and better active external rotation in neutral (p?=?0.01). Reparability was associated with tear shape (p?tendon quality (p?tears is affected by a number of clinical and surgical factors. Patients whose tears could not be fully repaired showed a statistically significant improvement in range of motion, strength and disability at 2 years, although they had slightly inferior results compared to those with complete repairs. PMID:24884835

  17. Multi-Layer Electrospun Membrane Mimicking Tendon Sheath for Prevention of Tendon Adhesions

    PubMed Central

    Jiang, Shichao; Yan, Hede; Fan, Dapeng; Song, Jialin; Fan, Cunyi

    2015-01-01

    Defect of the tendon sheath after tendon injury is a main reason for tendon adhesions, but it is a daunting challenge for the biomimetic substitute of the tendon sheath after injury due to its multi-layer membrane-like structure and complex biologic functions. In this study, a multi-layer membrane with celecoxib-loaded poly(l-lactic acid)-polyethylene glycol (PELA) electrospun fibrous membrane as the outer layer, hyaluronic acid (HA) gel as middle layer, and PELA electrospun fibrous membrane as the inner layer was designed. The anti-adhesion efficacy of this multi-layer membrane was compared with a single-layer use in rabbit flexor digitorum profundus tendon model. The surface morphology showed that both PELA fibers and celecoxib-loaded PELA fibers in multi-layer membrane were uniform in size, randomly arrayed, very porous, and smooth without beads. Multi-layer membrane group had fewer peritendinous adhesions and better gliding than the PELA membrane group and control group in gross and histological observation. The similar mechanical characteristic and collagen expression of tendon repair site in the three groups indicated that the multi-layer membrane did not impair tendon healing. Taken together, our results demonstrated that such a biomimetic multi-layer sheath could be used as a potential strategy in clinics for promoting tendon gliding and preventing adhesion without poor tendon healing. PMID:25822877

  18. Fiber Bragg grating displacement sensor for movement measurement of tendons and ligaments

    NASA Astrophysics Data System (ADS)

    Ren, Liang; Song, Gangbing; Conditt, Michael; Noble, Philip C.; Li, Hongnan

    2007-10-01

    Biomechanical studies often involve measurements of the strains developed in tendons or ligaments in posture or locomotion. Fiber-optic sensors present an attractive option for the measurement of strains in tendons and ligaments because of their low cost, ease of implementation, and increased accuracy compared with other implantable transducers. A new displacement sensor based on a fiber Bragg grating and shape memory alloy technology is proposed for the monitoring of tendon and ligament strains in different postures and in locomotion. After sensor calibration in the laboratory, a comparison of the fiber sensors and traditional camera displacement sensors was carried out to evaluate the performance of the fiber sensor during the application of tension to the Achilles tendon. Additional experiments were performed in cadaver knees to assess the suitability of these fiber sensors to measure ligament deformation in a variety of simulated postures. The results demonstrate that the proposed fiber Bragg grating sensor is a highly accurate, easily implantable, and minimally invasive method of measuring tendon and ligament displacement.

  19. Meniscal root tears: significance, diagnosis, and treatment.

    PubMed

    Bhatia, Sanjeev; LaPrade, Christopher M; Ellman, Michael B; LaPrade, Robert F

    2014-12-01

    Meniscal root tears, less common than meniscal body tears and frequently unrecognized, are a subset of meniscal injuries that often result in significant knee joint disorders. The meniscus root attachment aids meniscal function by securing the meniscus in place and allowing for optimal shock-absorbing function in the knee. With root tears, meniscal extrusion often occurs, and the transmission of circumferential hoop stresses is impaired. This alters knee biomechanics and kinematics and significantly increases tibiofemoral contact pressure. In recent years, meniscal root tears, which by definition include direct avulsions off the tibial plateau or radial tears adjacent to the root itself, have attracted attention because of concerns that significant meniscal extrusion dramatically inhibits normal meniscal function, leading to a condition biomechanically similar to a total meniscectomy. Recent literature has highlighted the importance of early diagnosis and treatment; fortunately, these processes have been vastly improved by advances in magnetic resonance imaging and arthroscopy. This article presents a review of the clinically relevant anatomic, biomechanical, and functional descriptions of the meniscus root attachments, as well as current strategies for accurate diagnosis and treatment of common injuries to these meniscus root attachments. PMID:24623276

  20. Gyrokinetic Simulations of Low- n Tearing Modes

    NASA Astrophysics Data System (ADS)

    Chen, Yang; Chowdhury, Jugal; Wan, Weigang; Parker, Scott

    2014-10-01

    Low-n tearing modes in cylintrical plasmas are studied with the GEM code using the gyrokinetic ion/fluid electron model. Particle trajectories and the evolution equations for A? and ? are advanced in the field-line-following coordinates, but new field solvers for the vorticity equation and the Ampere's law are developed for global, low-n modes to avoid the usual high-n approximations made in the Laplacian ??2 operator in gyrokinetic simulations. Since the tearing mode growth rate is small, numerical dissipation must be minimized. The hybrid model properly reduces to the reduced MHD model when ion kinetic effects are neglected. Eigenmode analysis for the reduced MHD cylindrical tearing mode problem has been developed to provide a direct verification of the simulation algorithms. Excellent agreement between the simulation and the eigenmode analysis is obtained for the tearing mode growth rate. When the finite-Larmor-radius effect in the ion polarization term in the vorticity equation is fully retained, simulations show an increase of the growth rate. The effects of gyrokinetic ions on the tearing mode stability will be studied and reported.

  1. [Flexor tendon repair: a short story].

    PubMed

    Moutet, F; Corcella, D; Forli, A; Mesquida, V

    2014-12-01

    This short story of flexor tendon repair aims to illustrate hesitations and wanderings of this surgery. Obviously tendon repair was very early considered, but it developed and diffused rather lately. It became a routine practice only in 20th century. This was due on the one hand, in Occident, to the Galen's dogmatic interdiction, on the other hand, to the repair difficulties of this paradoxical structure. Actually tendon is made of fibroblasts and collagen (sticky substances), and then its only goal is to move. According to this necessity, whatever the used techniques are, gliding is the final purpose. Technical evolutions are illustrated by historical contributions to flexor tendon surgery of several "giants" of hand surgery. PMID:24837978

  2. Position Control of Tendon-Driven Fingers

    NASA Technical Reports Server (NTRS)

    Abdallah, Muhammad E.; Platt, Robert, Jr.; Hargrave, B.; Pementer, Frank

    2011-01-01

    Conventionally, tendon-driven manipulators implement some force control scheme based on tension feedback. This feedback allows the system to ensure that the tendons are maintained taut with proper levels of tensioning at all times. Occasionally, whether it is due to the lack of tension feedback or the inability to implement sufficiently high stiffnesses, a position control scheme is needed. This work compares three position controllers for tendon-driven manipulators. A new controller is introduced that achieves the best overall performance with regards to speed, accuracy, and transient behavior. To compensate for the lack of tension feedback, the controller nominally maintains the internal tension on the tendons by implementing a two-tier architecture with a range-space constraint. These control laws are validated experimentally on the Robonaut-2 humanoid hand. I

  3. Tension Distribution in a Tendon-Driven Robotic Finger

    NASA Technical Reports Server (NTRS)

    Abdallah, Muhammad E. (Inventor); Platt, Robert (Inventor); Wampler, II, Charles W. (Inventor)

    2013-01-01

    A method is provided for distributing tension among tendons of a tendon-driven finger in a robotic system, wherein the finger characterized by n degrees of freedom and n+1 tendons. The method includes determining a maximum functional tension and a minimum functional tension of each tendon of the finger, and then using a controller to distribute tension among the tendons, such that each tendon is assigned a tension value less than the maximum functional tension and greater than or equal to the minimum functional tension. The method satisfies the minimum functional tension while minimizing the internal tension in the robotic system, and satisfies the maximum functional tension without introducing a coupled disturbance to the joint torques. A robotic system includes a robot having at least one tendon-driven finger characterized by n degrees of freedom and n+1 tendons, and a controller having an algorithm for controlling the tendons as set forth above.

  4. Disposition of collagen fibrils in human tendons.

    PubMed Central

    Stolinski, C

    1995-01-01

    Fixed and unfixed human tendons originating from cadavers and postoperation specimens were examined using inclined parallel beams of light in a reflecting mode. Along the tendon, numerous planes, constantly inclined to the axis, were observed edge-on at the surface and within the interior. Their angle of inclination, with respect to the distal end was very nearly +/- 50 degrees. The planes consisted of individual segments arranged in steps which were on average 190 x 50 microns. Similar configurations were also observed with the scanning electron microscope. Using this technique, the segments were identified with collagen bundles turning at a sharp angle with respect to the axis of the tendon at the level of the inclined plane. Crimped planes were found to be irregularly distributed along the tendons. On longer flatter tendons the average distance between planes was in the range of 1-12 mm. On stretching, the inclined pattern disappeared and was rapidly reestablished in the previously observed position when the strain was released. It is suggested that the observed structure forms a mechanism which is responsible for the appearance of the first part of 'foot' region of the tendon's stress-strain diagram. Images Fig. 1 Fig. 2 Fig. 3 Fig. 4 Fig. 5 Fig. 6 Fig. 7 PMID:7559130

  5. The cell biology of suturing tendons

    PubMed Central

    Wong, J.K.F.; Alyouha, S.; Kadler, K.E.; Ferguson, M.W.J.; McGrouther, D.A.

    2010-01-01

    Trauma by suturing tendon form areas devoid of cells termed “acellular zones” in the matrix. This study aimed to characterise the cellular insult of suturing and acellular zone formation in mouse tendon. Acellular zone formation was evaluated using single grasping sutures placed using flexor tendons with time lapse cell viability imaging for a period of 12 h. Both tension and injury were required to induce cell death and cell movement in the formation of the acellular zone. DNA fragmentation studies and transmission electron microscopy indicated that cells necrosed. Parallel in vivo studies showed that cell-to-cell contacts were disrupted following grasping by the suture in tensioned tendon. Without tension, cell death was lessened and cell-to-cell contacts remained intact. Quantitative immunohistochemistry and 3D cellular profile mapping of wound healing markers over a one year time course showed that acellular zones arise rapidly and showed no evidence of healing whilst the wound healing response occurred in the surrounding tissues. The acellular zones were also evident in a standard modified “Kessler” clinical repair. In conclusion, the suture repair of injured tendons produces acellular zones, which may potentially cause early tendon failure. PMID:20600895

  6. Evolution of the Achilles tendon: The athlete's Achilles heel?

    PubMed

    Malvankar, S; Khan, W S

    2011-12-01

    The Achilles tendon is believed to have first developed two million years ago enabling humans to run twice as fast. However if the Achilles tendon is so important in terms of evolution, then why is this tendon so prone to injury - especially for those more active like athletes. The Achilles tendon had an integral role in evolving apes from a herbivorous diet to early humans who started hunting for food over longer distances, resulting in bipedal locomotion. Evolutionary advantages of the Achilles tendon includes it being the strongest tendon in the body, having an energy-saving mechanism for fast locomotion, allows humans to jump and run, and additionally is a spring and shock absorber during gait. Considering these benefits it is therefore not surprising that studies have shown athletes have thicker Achilles tendons than subjects who are less active. However, contradictory to these findings that show the importance of the Achilles tendon for athletes, it is well known that obtaining an Achilles tendon injury for an athlete can be career-altering. A disadvantage of the Achilles tendon is that the aetiology of its pathology is complicated. Achilles tendon ruptures are believed to be caused by overloading the tensed tendon, like during sports. However studies have also shown athlete Achilles tendon ruptures to have degenerative changes in the tendon. Other flaws of the Achilles tendon are its non-uniform vascularity and incomplete repair system which may suggest the Achilles tendon is on the edge of evolution. Research has shown that there is a genetic influence on the predisposition a person has towards Achilles tendon injuries. So if this tendon is here to stay in our anatomy, and it probably is due to the slow rate of evolution in humans, research in genetic modification could be used to decrease athletes' predisposition to Achilles tendinopathy. PMID:21900004

  7. Arthroscopic treatment options for irreparable rotator cuff tears of the shoulder

    PubMed Central

    Anley, Cameron M; Chan, Samuel KL; Snow, Martyn

    2014-01-01

    The management of patients with irreparable rotator cuff tears remains a challenge for orthopaedic surgeons with the final treatment option in many algorithms being either a reverse shoulder arthroplasty or a tendon transfer. The long term results of these procedures are however still widely debated, especially in younger patients. A variety of arthroscopic treatment options have been proposed for patients with an irreparable rotator cuff tear without the presence of arthritis of the glenohumeral joint. These include a simple debridement with or without a biceps tenotomy, partial rotator cuff repair with or without an interval slide, tuberplasty, graft interposition of the rotator cuff, suprascapular nerve ablation, superior capsule reconstruction and insertion of a biodegradable spacer (Inspace) to depress the humeral head. These options should be considered as part of the treatment algorithm in patients with an irreparable rotator cuff and could be used as either as an interim procedure, delaying the need for more invasive surgery in the physiologically young and active, or as potential definitive procedures in the medically unfit. The aim of this review is to highlight and summarise arthroscopic procedures and the results thereof currently utilised in the management of these challenging patients. PMID:25405083

  8. An assessment of porcine dermal xenograft as an augmentation graft in the treatment of extensive rotator cuff tears.

    PubMed

    Badhe, Sachin P; Lawrence, Tom M; Smith, F D; Lunn, P G

    2008-01-01

    Porcine dermal collagen (Zimmer Patch, formerly known as Permacol; Tissue Science Laboratories plc, Aldershot, Hampshire, UK) has been used for reinforcement of several human body tissues with success and has been shown to act as a durable, permanent tissue scaffold that assists healing. The purpose of this study was to determine the effectiveness of porcine dermal collagen as a tendon augmentation graft in the repair of extensive rotator cuff tears. This prospective study evaluated the clinical, ultrasound, and magnetic resonance imaging outcome 4.5 years (range, 3-5 years) after the treatment of extensive rotator cuff tears with porcine dermal collagen tendon augmentation grafting. The study group consisted of 10 patients (5 men, 5 women) with a mean age of 66 years (range, 46-80 years). Patients were evaluated clinically using the Constant score preoperatively, at 1 year, and at final follow-up when ultrasound and magnetic resonance imaging scans were performed to assess for graft and rotator cuff integrity. Average Constant scores improved from 41 preoperatively to 62 at final follow-up (P = .0003). Pain, abduction power, and range of motion significantly improved after surgery (P < .05), and patient satisfaction levels were high. Imaging studies identified intact grafts in 8 patients and graft detachment in 2. No adverse side effects were reported during the study period. The use of porcine dermal collagen as an augmentation graft in the treatment of massive rotator cuff tears is safe and, in most patients, is associated with improved clinical outcome. Randomized trials are required to assess any benefit over standard current surgical treatment regimens. PMID:18201655

  9. Magnetotail dynamics excited by the streaming tearing mode

    NASA Technical Reports Server (NTRS)

    Sato, T.; Walker, R. J.

    1982-01-01

    Magnetotail reconnection in the presence of plasma streaming parallel to the neutral sheet is modeled. The tearing mode is excited much more violently in the case with parallel plasma flow in the plasma sheet than in the case with no flow. The flow patterns for the nonlinear resistive tearing mode and the streaming tearing mode are much more complex than those for the linear tearing mode. Flow vortices are observed in both cases.

  10. Flexor Digitorum Longus Tendon Transfer and Modified Kidner Technique in Posterior Tibial Tendon Dysfunction.

    PubMed

    Maskill, James T; Pomeroy, Gregory C

    2016-01-01

    The modified Kidner procedure and flexor digitorum longus tendon transfer are common procedures used today when addressing posterior tibial tendon dysfunction. These techniques are often used in conjunction with a combination of osteotomies to correct flatfoot deformity, and have been proved to be reliable and predictable. PMID:26590720

  11. Exploring Video Streams using Slit-Tear Visualizations

    E-print Network

    Greenberg, Saul

    Exploring Video Streams using Slit- Tear Visualizations Abstract Slit-tear visualizations allow users to selectively visualize pixel paths in a video scene. The slit-tear visualization technique is a generalization of the traditional photographic slit-scanning and more recent video slicing techniques: after

  12. Living with a symptomatic rotator cuff tear ‘bad days, bad nights’: a qualitative study

    PubMed Central

    2014-01-01

    Background Rotator cuff tears are a common cause of shoulder pain. There is an absence of information about symptomatic rotator cuffs from the patients’ perspective; this limits the information clinicians can share with patients and the information that patients can access via sources such as the internet. This study describes the experiences of people with a symptomatic rotator cuff, their symptoms, the impact upon their daily lives and the coping strategies utilised by study participants. Methods An interpretive phenomenological analysis approach was used. 20 participants of the UKUFF trial (The United Kingdom Rotator Cuff Surgery Trial) agreed to participate in in-depth semi-structured interviews about their experiences about living with a symptomatic rotator cuff tear. Interviews were digitally recorded and fully transcribed. Field notes, memos and a reflexive diary were used. Data was coded in accordance with interpretive phenomenological analysis. Peer review, code-recode audits and constant comparison of data, codes and categories occurred throughout. Results The majority of patients described intense pain and severely disturbed sleep. Limited movement and reduced muscle strength were described by some participants. The predominantly adverse impact that a symptomatic rotator cuff tear had upon activities of daily living, leisure activities and occupation was described. The emotional and financial impact and impact upon caring roles were detailed. Coping strategies included attempting to carry on as normally as possible, accepting their condition, using their other arm, using analgesics, aids and adaptions. Conclusions Clinicians need to appreciate and understand the intensity and shocking nature of pain that may be experienced by participants with known rotator cuff tears and understand the detrimental impact tears can have upon all areas of patient’s lives. Clinicians also need to be aware of the potential emotional impact caused by cuff tears and to ensure that patients needing help for conditions such as depression are speedily identified and provided with support, explanation and appropriate treatment. PMID:25008095

  13. Specialization of tendon mechanical properties results from interfascicular differences

    PubMed Central

    Thorpe, Chavaunne T.; Udeze, Chineye P.; Birch, Helen L.; Clegg, Peter D.; Screen, Hazel R. C.

    2012-01-01

    Tendons transfer force from muscle to bone. Specific tendons, including the equine superficial digital flexor tendon (SDFT), also store and return energy. For efficient function, energy-storing tendons need to be more extensible than positional tendons such as the common digital extensor tendon (CDET), and when tested in vitro have a lower modulus and failure stress, but a higher failure strain. It is not known how differences in matrix organization contribute to distinct mechanical properties in functionally different tendons. We investigated the properties of whole tendons, tendon fascicles and the fascicular interface in the high-strain energy-storing SDFT and low-strain positional CDET. Fascicles failed at lower stresses and strains than tendons. The SDFT was more extensible than the CDET, but SDFT fascicles failed at lower strains than CDET fascicles, resulting in large differences between tendon and fascicle failure strain in the SDFT. At physiological loads, the stiffness at the fascicular interface was lower in the SDFT samples, enabling a greater fascicle sliding that could account for differences in tendon and fascicle failure strain. Sliding between fascicles prior to fascicle extension in the SDFT may allow the large extensions required in energy-storing tendons while protecting fascicles from damage. PMID:22764132

  14. 21 CFR 888.3025 - Passive tendon prosthesis.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... (a) Identification. A passive tendon prosthesis is a device intended to be implanted made of silicon elastomer or a polyester reinforced medical grade silicone elastomer intended for use in the surgical reconstruction of a flexor tendon of...

  15. Robot Arm with Tendon Connector Plate and Linear Actuator

    NASA Technical Reports Server (NTRS)

    Ihrke, Chris A. (Inventor); Diftler, Myron A. (Inventor); Bridgwater, Lyndon (Inventor); Nguyen, Vienny (Inventor); Millerman, Alexander (Inventor)

    2014-01-01

    A robotic system includes a tendon-driven end effector, a linear actuator, a flexible tendon, and a plate assembly. The linear actuator assembly has a servo motor and a drive mechanism, the latter of which translates linearly with respect to a drive axis of the servo motor in response to output torque from the servo motor. The tendon connects to the end effector and drive mechanism. The plate assembly is disposed between the linear actuator assembly and the tendon-driven end effector and includes first and second plates. The first plate has a first side that defines a boss with a center opening. The second plate defines an accurate through-slot having tendon guide channels. The first plate defines a through passage for the tendon between the center opening and a second side of the first plate. A looped end of the flexible tendon is received within the tendon guide channels.

  16. Tendon crimps and peritendinous tissues responding to tensional forces.

    PubMed

    Franchi, M; Quaranta, M; De Pasquale, V; Macciocca, M; Orsini, E; Trirè, A; Ottani, V; Ruggeri, A

    2007-01-01

    Tendons transmit forces generated from muscle to bone making joint movements possible. Tendon collagen has a complex supramolecular structure forming many hierarchical levels of association; its main functional unit is the collagen fibril forming fibers and fascicles. Since tendons are enclosed by loose connective sheaths in continuity with muscle sheaths, it is likely that tendon sheaths could play a role in absorbing/transmitting the forces created by muscle contraction. In this study rat Achilles tendons were passively stretched in vivo to be observed at polarized light microscope (PLM), scanning electron microscope (SEM) and transmission electron microscope (TEM). At PLM tendon collagen fibers in relaxed rat Achilles tendons ran straight and parallel, showing a periodic crimp pattern. Similarly tendon sheaths showed apparent crimps. At higher magnification SEM and TEM revealed that in each tendon crimp large and heterogeneous collagen fibrils running straight and parallel suddenly changed their direction undergoing localized and variable modifications. These fibril modifications were named fibrillar crimps. Tendon sheaths displayed small and uniform fibrils running parallel with a wavy course without any ultrastructural aspects of crimp. Since in passively stretched Achilles tendons fibrillar crimps were still observed, it is likely that during the tendon stretching, and presumably during the tendon elongation in muscle contraction, the fibrillar crimp may be the real structural component of the tendon crimp acting as shock absorber. The peritendinous sheath can be stretched as tendon, but is not actively involved in the mechanism of shock absorber as the fibrillar crimp. The different functional behaviour of tendons and sheaths may be due to the different structural and molecular arrangement of their fibrils. PMID:17703588

  17. Sex Differences in Outcome After an Acute Achilles Tendon Rupture

    PubMed Central

    Grävare Silbernagel, Karin; Brorsson, Annelie; Olsson, Nicklas; Eriksson, Bengt I.; Karlsson, Jon; Nilsson-Helander, Katarina

    2015-01-01

    Background: Tendon healing differs between the sexes. Comparisons in outcome between the sexes after an Achilles tendon rupture are often not possible because of the small cohort (<20%) of women. Purpose: To evaluate whether there are any differences in outcome between the sexes by combining the data from 2 large randomized controlled trials that used identical outcome measures. Study Design: Cohort study; Level of evidence, 3. Methods: Included in the evaluation were patients from 2 consecutive randomized controlled trials comparing surgical and nonsurgical treatment performed at our research laboratory. Patients who had a rerupture were excluded from analysis. A total of 182 patients (152 males, 30 females), with mean ± SD age of 40 ± 11 years, were included; 94 (76 males, 18 females) were treated with surgery and 88 (76 males, 12 females) nonsurgically. Patient-reported outcome was evaluated using the Achilles tendon Total Rupture Score (ATRS), and the functional outcome was measured with a heel-rise test (measurement of muscular endurance and heel-rise height) at 6 and 12 months after injury. Results: Male patients had a greater improvement in heel-rise height at 12 months (P = .004). When each treatment group was analyzed separately, it was found that female patients had significantly (P < .03) more symptoms after surgical treatment (mean ± SD ATRS, 59 ± 24) compared with males at 6 (73 ± 19) and 12 months (74 ± 27 vs 86.5 ± 17). This sex difference was not found in the nonsurgical treatment group. For the entire group, there were no significant differences between treatments on ATRS at 6 and 12 months. The surgical group had significantly better results compared with the nonsurgical group in heel-rise endurance at 6 and 12 months and in heel-rise height recovery at 6 months (P < .03 for both). Conclusion: Sex differences were demonstrated, and female patients had a greater degree of deficit in heel-rise height as compared with males, irrespective of treatment. Females had more symptoms after surgery both at 6 and 12 months, but this difference was not found when treated nonsurgically. Clinical Relevance: Further research is needed to determine whether women will benefit more from nonsurgical compared with surgical treatment after an Achilles tendon rupture.

  18. 21 CFR 888.3025 - Passive tendon prosthesis.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Passive tendon prosthesis. 888.3025 Section 888...) MEDICAL DEVICES ORTHOPEDIC DEVICES Prosthetic Devices § 888.3025 Passive tendon prosthesis. (a) Identification. A passive tendon prosthesis is a device intended to be implanted made of silicon elastomer or...

  19. 21 CFR 888.3025 - Passive tendon prosthesis.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Passive tendon prosthesis. 888.3025 Section 888...) MEDICAL DEVICES ORTHOPEDIC DEVICES Prosthetic Devices § 888.3025 Passive tendon prosthesis. (a) Identification. A passive tendon prosthesis is a device intended to be implanted made of silicon elastomer or...

  20. 21 CFR 888.3025 - Passive tendon prosthesis.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Passive tendon prosthesis. 888.3025 Section 888...) MEDICAL DEVICES ORTHOPEDIC DEVICES Prosthetic Devices § 888.3025 Passive tendon prosthesis. (a) Identification. A passive tendon prosthesis is a device intended to be implanted made of silicon elastomer or...

  1. 21 CFR 888.3025 - Passive tendon prosthesis.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Passive tendon prosthesis. 888.3025 Section 888...) MEDICAL DEVICES ORTHOPEDIC DEVICES Prosthetic Devices § 888.3025 Passive tendon prosthesis. (a) Identification. A passive tendon prosthesis is a device intended to be implanted made of silicon elastomer or...

  2. 21 CFR 888.3025 - Passive tendon prosthesis.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Passive tendon prosthesis. 888.3025 Section 888...) MEDICAL DEVICES ORTHOPEDIC DEVICES Prosthetic Devices § 888.3025 Passive tendon prosthesis. (a) Identification. A passive tendon prosthesis is a device intended to be implanted made of silicon elastomer or...

  3. An Overview of the Management of Flexor Tendon Injuries

    PubMed Central

    Griffin, M; Hindocha, S; Jordan, D; Saleh, M; Khan, W

    2012-01-01

    Flexor tendon injuries still remain a challenging condition to manage to ensure optimal outcome for the patient. Since the first flexor tendon repair was described by Kirchmayr in 1917, several approaches to flexor tendon injury have enabled successful repairs rates of 70-90%. Primary surgical repair results in better functional outcome compared to secondary repair or tendon graft surgery. Flexor tendon injury repair has been extensively researched and the literature demonstrates successful repair requires minimal gapping at the repair site or interference with tendon vascularity, secure suture knots, smooth junction of tendon end and having sufficient strength for healing. However, the exact surgical approach to achieve success being currently used among surgeons is still controversial. Therefore, this review aims to discuss the results of studies demonstrating the current knowledge regarding the optimal approach for flexor tendon repair. Post-operative rehabilitation for flexor tendon surgery is another area, which has caused extensive debate in hand surgery. The trend to more active mobilisation protocols seems to be favoured but further study in this area is needed to find the protocol, which achieves function and gliding but avoids rupture of the tendons. Lastly despite success following surgery complications commonly still occur post surgery, including adhesion formation, tendon rupture and stiffness of the joints. Therefore, this review aims to discuss the appropriate management of these difficulties post surgery. New techniques in management of flexor tendon will also be discussed including external laser devices, addition of growth factors and cytokines. PMID:22431948

  4. Comparative Study on Functional Effects of Allotransplantation of Bone Marrow Stromal Cells and Adipose Derived Stromal Vascular Fraction on Tendon Repair: A Biomechanical Study in Rabbits

    PubMed Central

    Behfar, Mehdi; Javanmardi, Sara; Sarrafzadeh-Rezaei, Farshid

    2014-01-01

    Objective Tendon never returns to its complete biological and mechanical properties after repair. Bone marrow and, recently, adipose tissue have been used as sources of mesenchymal stem cells which have been proven to enhance tendon healing. In the present study, we compared the effects of allotransplantation of bone marrow derived mesenchymal stromal cells (BMSCs) and adipose derived stromal vascular fraction (SVF) on tendon mechanical properties after experimentally induced flexor tendon transection. Materials and Methods In this experimental study, we used 48 adult male New Zealand white rabbits. Twelve of rabbits were used as donors of bone marrow and adipose tissue, the rest were divided into control and treatment groups. The injury model was a unilateral complete transection of the deep digital flexor tendon. Immediately after suture repair, 4×106cells of either fresh SVF from enzymatic digestion of adipose tissue or cultured BMSCs were intratendinously injected into tendon stumps in the treatment groups. Controls received phosphate-buffered saline (PBS). Immobilization with a cast was continued for two weeks after surgery. Animals were sacrificed three and eight weeks after surgery and tendons underwent mechanical evaluations. The differences among the groups were analyzed using the analysis of variance (ANOVA) test followed by Tukey’s multiple comparisons test. Results Stromal cell transplantation resulted in a significant increase in ultimate and yield loads, energy absorption, and stress of repairs compared to the controls. However, there were no statistically significant changes detected in terms of stiffness. In comparison, we observed no significant differences at the third week between SVF and BMSCs treated tendons in terms of all load related properties. However, at the eighth week SVF transplantation resulted in significantly increased energy absorption, stress and stiffness compared to BMSCs. Conclusion The enhanced biomechanical properties of repairs in this study advocates the application of adipose derived SVF as an excellent source of multipotent cells instead of traditional BMSCs and may seem more encouraging in cell-based therapy for tendon injuries. PMID:24611149

  5. A Comparison of Two Injection Locations in Obese Patients Having Lower Leg/Foot Surgery

    ClinicalTrials.gov

    2015-10-13

    Strain of Muscle and/or Tendon of Lower Leg; Fracture of Lower Leg; Crushing Injury of Lower Leg; Fracture Malunion - Ankle and/ or Foot; Complete Tear, Ankle and/or Foot Ligament; Pathological Fracture - Ankle and/or Foot; Loose Body in Joint of Ankle and/or Foot

  6. Biodegradable synthetic scaffolds for tendon regeneration

    PubMed Central

    Reverchon, Ernesto; Baldino, Lucia; Cardea, Stefano; De Marco, Iolanda

    2012-01-01

    Summary Tissue regeneration is aimed at producing biological or synthetic scaffolds to be implanted in the body for regenerate functional tissues. Several techniques and materials have been used to obtain biodegradable synthetic scaffolds, on which adhesion, growth, migration and differentiation of human cells has been attempted. Scaffolds for tendon regeneration have been less frequently proposed, because they have a complex hierarchical structure and it is very difficult to mimic their peculiar mechanical properties. In this review, we critically analyzed the proposed materials and fabrication techniques for tendon tissue engineering and we indicated new preparation processes, based on the use of supercritical fluids, to produce scaffolds with characteristics very similar to the native tendon structure. PMID:23738295

  7. A Comparative Study of the Effects of Growth and Differentiation Factor 5 on Muscle Derived Stem Cells and Bone Marrow Stromal Cells in an In Vitro Tendon Healing Model

    PubMed Central

    Ozasa, Yasuhiro; Gingery, Anne; Thoreson, Andrew R.; An, Kai-Nan; Zhao, Chunfeng; Amadio, Peter C.

    2014-01-01

    Purpose To investigate the ability of muscle derived stem cells (MDSCs) supplemented with growth and differentiation factor-5 (GDF-5) to improve tendon healing in comparison to bone marrow stromal cells (BMSCs), in an in vitro tendon culture model. Methods Eighty canine flexor digitorum profundus tendons were assigned into 5 groups: 1) repaired tendon without gel patch interposition (no cell group), 2) with BMSC seeded gel patch interposition (BMSC group), 3) with MDSC seeded gel patch interposition (MDSC group), 4) with GDF-5 treated BMSC seeded gel patch interposition (BMSC+GDF-5 group), and 5) with GDF-5 treated MDSC seeded gel patch interposition (MDSC+GDF-5 group). After culturing for 2 or 4 weeks, the failure strength of the healing tendons was measured. The tendons were also evaluated histologically. Results The failure strength of the repaired tendon in the MDSC+GDF-5 group was significantly higher than that of the no cell and BMSC groups. The stiffness of the repaired tendons in the MDSC+GDF-5 group was significantly higher than that of the no cell group. Histologically, the implanted cells became incorporated into the original tendon in all 4 cell-seeded groups. Conclusion Interposition of a multi-layered GDF-5 and MDSC-seeded collagen gel patch at the repair site enhanced tendon healing compared to a similar patch using BMSC. However, this increase in vitro was relatively small. In the clinical setting, differences between MDSC and BMSC may not be substantially different, and it remains to be shown that such methods might enhance the results of an uncomplicated tendon repair clinically. Clinical Relevance MDSC implantation and administration of GDF-5 may improve the outcome of tendon repair. PMID:24909566

  8. Spontaneous Achilles tendon rupture in alkaptonuria.

    PubMed

    Alajoulin, Omar A; Alsbou, Mohammed S; Ja'afreh, Somayya O; Kalbouneh, Heba M

    2015-12-01

    Alkaptonuria (AKU) is a rare inborn metabolic disease characterized by accumulation of homogentisic acid (HGA). Excretion of HGA in urine causes darkening of urine and its deposition in connective tissues causes dark pigmentation (ochronosis), early degeneration of articular cartilage, weakening of the tendons, and subsequent rupture. In this case report, we present a rare case of a patient presented with unilateral spontaneous rupture of Achilles tendon due to AKU. The patient developed most of the orthopedic manifestations of the disease earlier than typical presentations. Alkaptonuria patients should avoid strenuous exercises and foot straining especially in patients developing early orthopedic manifestations. PMID:26620992

  9. Biceps Tenodesis for Type II SLAP Tears.

    PubMed

    Tayrose, Gregory A; Karas, Spero G; Bosco, Joseph

    2015-06-01

    Tears of the superior glenoid labrum are a common cause ofshoulder pain and disability, especially in overhead athletessuch as pitchers, swimmers, and volleyball players. Type IISLAP lesions have been the most clinically important superiorlabral pathology, and the management of this lesionhas been a very controversial topic. Currently, there are nohigh level studies in the literature to guide treatment. Whilethe few level 3 and level 4 evidence studies that are availablefollowing arthroscopic repair of type II SLAP lesionsall report reasonable overall patient satisfaction, persistentpostoperative pain is common and associated with a lowreturn to pre-injury level of sports participation. There hasbeen a recent school of thought that biceps tenodesis, whichmaintains the length-tension relationship of the long head ofbiceps, should be the procedure of choice for patients withisolated type II SLAP lesions. The current paper reviewsthe role biceps tenodesis plays in the management of typeII SLAP tears. PMID:26517164

  10. Analysis and simulation of double tearing modes

    NASA Astrophysics Data System (ADS)

    Nishimura, Y.; Chen, J. M.; Cheng, C. Z.

    2014-10-01

    Tokamak experiments with non-monotonic q-profile have attracted attention to the stability problem of double tearing modes. Interestingly, double tearing modes are one of the good examples where the pressure anisotropy effects become prominent. The bootstrap current contribution on the ? ' depends on the sign of (dp / dr) / s (s is the magnetic shear, (dp / dr) is the pressure gradient), which is different on the inner surface and the outer surface, The ? ' matrix, including off diagonal elements are calculated by solving exterior equation. The analysis is compare with the numerical results from a three dimensional initial value simulation. The nonlinear evolution of toroidally asymmetric m / n = 2 / 1 island chains has been investigated. To incorporate the pressure anisotropy, the kinetic-fluid model is employed which replace the pressure evolution equation with the second order moment of the kinetic ions and electrons from kinetic (particle) simulation.

  11. The role of animal models in tendon research

    PubMed Central

    Hast, M. W.; Zuskov, A.; Soslowsky, L. J.

    2014-01-01

    Tendinopathy is a debilitating musculoskeletal condition which can cause significant pain and lead to complete rupture of the tendon, which often requires surgical repair. Due in part to the large spectrum of tendon pathologies, these disorders continue to be a clinical challenge. Animal models are often used in this field of research as they offer an attractive framework to examine the cascade of processes that occur throughout both tendon pathology and repair. This review discusses the structural, mechanical, and biological changes that occur throughout tendon pathology in animal models, as well as strategies for the improvement of tendon healing. Cite this article: Bone Joint Res 2014;3:193–202. PMID:24958818

  12. Gyrokinetic framework for Neoclassical Tearing Modes

    NASA Astrophysics Data System (ADS)

    Tronko, Natalia; Wilson, Howard; Brizard, Alain

    2013-10-01

    We are developing a new theoretical framework based on the Hamiltonian Gyrokinetics for description of the Neoclassical Tearing Modes dynamics. The main advantage of this approach is the possibility of systematically including effects of magnetic geometry as well as magnetic field fluctuations due to the presence of a magnetic island. Moreover it makes it possible to systematically compute the expression for the polarization current as well as including FLR effects. This work represents an extension of previous drift-kinetic models for NTMs.

  13. Conditioning of the Achilles tendon via ankle exercise improves correlations between sonographic measures of tendon thickness and body anthropometry.

    PubMed

    Wearing, Scott C; Grigg, Nicole L; Hooper, Sue L; Smeathers, James E

    2011-05-01

    Although conditioning is routinely used in mechanical tests of tendon in vitro, previous in vivo research evaluating the influence of body anthropometry on Achilles tendon thickness has not considered its potential effects on tendon structure. This study evaluated the relationship between Achilles tendon thickness and body anthropometry in healthy adults both before and after resistive ankle plantarflexion exercise. A convenience sample of 30 healthy male adults underwent sonographic examination of the Achilles tendon in addition to standard anthropometric measures of stature and body weight. A 10-5 MHz linear array transducer was used to acquire longitudinal sonograms of the Achilles tendon, 20 mm proximal to the tendon insertion. Participants then completed a series (90-100 repetitions) of conditioning exercises against an effective resistance between 100% and 150% body weight. Longitudinal sonograms were repeated immediately on completion of the exercise intervention, and anteroposterior Achilles tendon thickness was determined. Achilles tendon thickness was significantly reduced immediately following conditioning exercise (t = 9.71, P < 0.001), resulting in an average transverse strain of -18.8%. In contrast to preexercise measures, Achilles tendon thickness was significantly correlated with body weight (r = 0.72, P < 0.001) and to a lesser extent height (r = 0.45, P = 0.01) and body mass index (r = 0.63, P < 0.001) after exercise. Conditioning of the Achilles tendon via resistive ankle exercises induces alterations in tendon structure that substantially improve correlations between Achilles tendon thickness and body anthropometry. It is recommended that conditioning exercises, which standardize the load history of tendon, are employed before measurements of sonographic tendon thickness in vivo. PMID:21393469

  14. Tendon matrix composition and turnover in relation to functional requirements.

    PubMed

    Birch, Helen L

    2007-08-01

    Tendons are dense regular connective tissue structures that are defined based on their anatomical position of connecting muscle to bone. Despite these obvious commons features tendons from different locations within the body show remarkable variation in terms of their morphological, molecular and mechanical properties which relates to their specialized function. An appreciation of these differences is necessary to understand all aspects of tendon biology in health and disease. In our work, we have used a combination of mechanical assessment, histological measurements and molecular analysis of matrix in functionally distinct tendons to determine relationships between function and structure. We have found significant differences in material and molecular properties between spring-like tendons that are subjected to high strains during locomotion and positional tendons which are subjected to much lower strains. Furthermore, we have data to suggest that not only is the matrix composition different but also the ability of cells to synthesize and degrade the matrix (matrix turnover) varies between tendon types. We propose that these differences relate to the magnitude of strain that the tendon experiences during normal activities in life. Tendon cells may be preprogrammed during embryological development for the strain they will encounter in life or may simply respond to the particular strain environment they are subjected to. The elucidation of controlling mechanisms resulting in tendon cell specialization will have important consequences for cell based therapies and engineering strategies to repair damaged tendons. PMID:17696905

  15. Combined Tendon and Bone Allograft Transplantation for Chronic Achilles Tendon Ruptures.

    PubMed

    Catanzariti, Alan R; Hentges, Matthew

    2016-01-01

    Combined flexor hallucis longus tendon transfer and bone-tendon allograft transplantation is a reasonable option for advanced distal-segment Achilles tendinopathy. This procedure provides anatomic restoration and improved function of the posterior muscle group without sacrificing the regional anatomy. Allograft transplantation is safe and does not require immunosuppressive therapy. The soft tissue envelope should be healthy because wound complications can be an issue. This procedure is especially helpful in patients with significant disability. PMID:26590730

  16. [The history of flexor tendon surgery].

    PubMed

    Chamay, A

    1997-01-01

    Flexor tendon injuries were already treated in antiquity by Hippocrates, Galien and Avicenne. Since the Renaissance, other surgeons have attempted to repair flexor tendon injuries, but without success due to problems related to unsuitable materials and ignorance of the basic rules of asepsis and the absence of antiseptics until the second half of the 19th century. The first successful flexor tendon grafts in man were performed by K. Biesalski in 1910, E. Lexer in 1912 and L. Mayer in 1916. These three authors published their series of grafts and described in detail the anatomical, physiological and technical principles to be respected. St. Bunnell, in 1918, developed various pull-out direct suture procedures, but faced with the problems of adhesions, he abandoned this technique and proposed not to repair flexors in the digital tunnels but to graft them. He defined the famous zone which he called No man's land, which subsequently became Claude Verdan's zone II, in 1959. In 1960, C. Verdan published his first series of sutures maintained by 2 pins in zone II with comparable results to those obtained after grafting. In 1967, H. Kleinert, with his mobile suture, became the leader of direct tendon repair in zone II. 2-stage grafts were introduced in 1965 under the impetus of J. Hunter, who revised and popularized the studies conducted by A. Bassett and R.E. Caroll in 1950. PMID:9131943

  17. Minimally Invasive Approach to Achilles Tendon Pathology.

    PubMed

    Hegewald, Kenneth W; Doyle, Matthew D; Todd, Nicholas W; Rush, Shannon M

    2016-01-01

    Many surgical procedures have been described for Achilles tendon pathology; however, no overwhelming consensus has been reached for surgical treatment. Open repair using a central or paramedian incision allows excellent visualization for end-to-end anastomosis in the case of a complete rupture and detachment and reattachment for insertional pathologies. Postoperative wound dehiscence and infection in the Achilles tendon have considerable deleterious effects on overall functional recovery and outcome and sometimes require plastic surgery techniques to achieve coverage. With the aim of avoiding such complications, foot and ankle surgeons have studied less invasive techniques for repair. We describe a percutaneous approach to Achilles tendinopathy using a modification of the Bunnell suture weave technique combined with the use of interference screws. No direct end-to-end repair of the tendon is performed, rather, the proximal stump is brought in direct proximity of the distal stump, preventing overlengthening and proximal stump retraction. This technique also reduces the suture creep often seen with end-to-end tendon repair by providing a direct, rigid suture to bone interface. We have used the new technique to minimize dissection and exposure while restoring function and accelerating recovery postoperatively. PMID:26385574

  18. Engaging Stem Cells for Customized Tendon Regeneration

    PubMed Central

    Thaker, Hatim; Sharma, Arun K.

    2012-01-01

    The need for a consistent therapeutic approach to tendon injury repair is long overdue. Patients with tendon microtears or full ruptures are eligible for a wide range of invasive and non invasive interventions, often subjectively decided by the physician. Surgery produces the best outcomes, and while studies have been conducted to optimize graft constructs and to track outcomes, the data from these studies have been inconclusive on the whole. What has been established is a clear understanding of healthy tendon architecture and the inherent process of healing. With this knowledge, tissue regeneration efforts have achieved immense progress in scaffold design, cell line selection, and, more recently, the appropriate use of cytokines and growth factors. This paper evaluates the plasticity of bone-marrow-derived stem cells and the elasticity of recently developed biomaterials towards tendon regeneration efforts. Mesenchymal stem cells (MSCs), hematopoietic progenitor cells, and poly(1,8-octanediol co-citrate) scaffolds (POC) are discussed in the context of established grafting strategies. With POC scaffolds to cradle the growth of MSCs and hematopoietic progenitor cells, developing a fibroelastic network guided by cytokines and growth factors may contribute towards consistent graft constructs, enhanced functionality, and better patient outcomes. PMID:22685473

  19. On muscle, tendon and high heels.

    PubMed

    Csapo, R; Maganaris, C N; Seynnes, O R; Narici, M V

    2010-08-01

    Wearing high heels (HH) places the calf muscle-tendon unit (MTU) in a shortened position. As muscles and tendons are highly malleable tissues, chronic use of HH might induce structural and functional changes in the calf MTU. To test this hypothesis, 11 women regularly wearing HH and a control group of 9 women were recruited. Gastrocnemius medialis (GM) fascicle length, pennation angle and physiological cross-sectional area (PCSA), the Achilles' tendon (AT) length, cross-sectional area (CSA) and mechanical properties, and the plantarflexion torque-angle and torque-velocity relationships were assessed in both groups. Shorter GM fascicle lengths were observed in the HH group (49.6+/-5.7 mm vs 56.0+/-7.7 mm), resulting in greater tendon-to-fascicle length ratios. Also, because of greater AT CSA, AT stiffness was higher in the HH group (136.2+/-26.5 N mm(-1) vs 111.3+/-20.2 N mm(-1)). However, no differences in the GM PCSA to AT CSA ratio, torque-angle and torque-velocity relationships were found. We conclude that long-term use of high-heeled shoes induces shortening of the GM muscle fascicles and increases AT stiffness, reducing the ankle's active range of motion. Functionally, these two phenomena seem to counteract each other since no significant differences in static or dynamic torques were observed. PMID:20639419

  20. Avoiding Anomalous Tendon Harvest at the Pes Anserinus Insertion.

    PubMed

    Cidambi, Krishna R; Pennock, Andrew T; Dwek, Jerry R; Edmonds, Eric W

    2016-01-01

    The purpose of this study was to identify the frequency and characteristics of anomalous pes anserinus tendon morphology in an adolescent population undergoing knee anterior cruciate ligament (ACL) reconstruction surgery. The records of all children who underwent ACL reconstruction surgery at our tertiary care children's hospital from June 2008 through February 2012 were reviewed. Operative reports were reviewed for any indication that an anomaly existed in the pes anserinus or that there was difficulty harvesting the required tendons. Magnetic resonance imaging (MRI) studies were then reviewed for these patients looking for evidence of any anomaly within the pes anserinus structures. Retrospective review was performed on 123 children (mean age, 16.1 years). Three girls (mean age, 16.2 years) were identified as having a low-lying muscle belly and accessory tendon when attempting to harvest the gracilis tendon. Proximal exploration of this short tendon conjoining the gracilis insertion revealed a muscle belly approximately 5 cm from its insertion in the pes anserinus. This anomaly was present in 2.4% of the cases. Based on previous literature, the anomalous muscle present in our cohort could be sartorius or semimembranosus. MRI analysis suggests that the accessory muscle and tendon could be an aberrant strip of the semimembranosus tendon, an anomalous tendon and muscle belly of the gracilis, or a thickening and separation of the sartorius tendon. Anomalous pes anserinus tendons were found to exist in 2.4% of our adolescent study population. At the time of surgery, if a tendon is harvested with a very low-lying muscle belly (with less than 6 cm of tendon), then the presence of an aberrant tendon should be considered. Preoperative MRI may provide evidence of an anomalous tendon if that information is sought. PMID:25556897

  1. Patient Acceptability of Tear Collection in the Primary Healthcare Setting

    PubMed Central

    Quah, Joanne Hui Min; Tong, Louis; Barbier, Sylvaine

    2014-01-01

    ABSTRACT Purpose The primary healthcare setting is well placed for health screening. Tear fluid composition gives valuable information about the eye and systemic health, and there is now significant interest in the potential application of tears as a tool for health screening; however, the acceptability of tear collection in the primary healthcare setting as compared with other methods of human sample collection has not been previously addressed. The objective of this study was to evaluate the patient acceptability of tear collection in a primary healthcare setting. Methods This was a cross-sectional study on 383 adult patients seeking primary healthcare, who were not diabetic and were not attending for an eye-related complaint. Tear collection was done using Schirmer strips, and an interviewer-administered questionnaire was conducted to collate information on the pain score (0–10) of the Schirmer tear collection, as well as to score the pain associated with their previous experience of antecubital venous puncture and finger prick test. Results The pain score for Schirmer tear collection was significantly lower (p < 0.001) than antecubital venous puncture but higher (p < 0.001) than finger prick. The pain scores for all three procedures were significantly higher in participants of younger age, female gender, and higher education level. Among the participants, 70% did not mind their tears being collected to screen for eye problems, whereas only 38% did not mind this procedure being performed for general health screening. Nevertheless, 69% of the participants preferred tear to urine collection, and 74% of participants preferred tear to blood collection. Conclusions Tear collection using Schirmer strips is a highly acceptable form of investigation that has the potential for use in health screening in the primary healthcare setting. This study has implications on using tear collection as a method of ocular and systemic health screening in the primary healthcare setting. PMID:24492756

  2. Tear film osmolality and electrolyte composition in healthy horses.

    PubMed

    Best, Lori J; Hendrix, Diane V H; Ward, Daniel A

    2015-12-01

    OBJECTIVE To evaluate the tear film osmolality and electrolyte composition in healthy horses. ANIMALS 15 healthy adult horses. PROCEDURES Each horse was manually restrained, and an ophthalmic examination, which included slit-lamp biomicroscopy, indirect ophthalmoscopy, and a Schirmer tear test, was performed. Tear samples were collected from both eyes with microcapillary tubes 3 times at 5-minute intervals. The tear samples for each horse were pooled, and the osmolality and electrolyte concentrations were measured. The mean (SD) was calculated for each variable to establish preliminary guidelines for tear film osmolality and electrolyte composition in healthy horses. RESULTS The mean (SD) tear film osmolality was 283.51 (9.33) mmol/kg, and the mean (SD) sodium, potassium, magnesium, and calcium concentrations were 134.75 (10), 16.3 (5.77), 3.48 (1.97), and 1.06 (0.42) mmol/L, respectively. The sodium concentration in the tear film was similar to that in serum, whereas the potassium concentration in the tear film was approximately 4.75 times that of serum. CONCLUSIONS AND CLINICAL RELEVANCE Results provided preliminary guidelines with which tear samples obtained from horses with keratopathies can be compared. Measurement of tear film osmolality in these horses was easy and noninvasive. The tear film concentration of divalent cations was greater than expected and was higher than the divalent cation concentrations in the tear films of rabbits and humans. These data may be clinically useful for the diagnosis and monitoring of hyperosmolar ocular surface disease in horses. PMID:26618731

  3. Onset Time of Nerve Block: A Comparison of Two Injection Locations in Patients Having Lower Leg/ Foot Surgery

    ClinicalTrials.gov

    2014-03-20

    Strain of Muscle and/or Tendon of Lower Leg; Fracture of Lower Leg; Crushing Injury of Lower Leg; Fracture Malunion - Ankle and/or Foot; Disorder of Joint of Ankle and/or Foot; Complete Tear, Ankle and/or Foot Ligament; Pathological Fracture - Ankle and/or Foot; Loose Body in Joint of Ankle and/or Foot

  4. Stabilization of tearing modes by oscillating the resonant surface

    SciTech Connect

    Yang Xiaoqing; Wang Shaojie; Yang Weihong

    2012-07-15

    The effects of the plasma current modulation on the linear instability of the tearing mode are numerically investigated. It is found that the tearing mode can be stabilized if the frequency of the modulation is suitable and the oscillation amplitude of the resonant surface position is large enough. The power needed for the lower-hybrid-current-drive to stabilize the tearing mode by oscillating the position of the resonant surface is comparable to the power consumption of the conventional method of tearing mode stabilization by using the electron-cyclotron-current-drive.

  5. Arthroscopic all inside repair of the lateral meniscus root tear.

    PubMed

    Ahn, Jin Hwan; Lee, Yong Seuk; Chang, Jae-Young; Chang, Moon Jong; Eun, Sang Soo; Kim, Sang Min

    2009-01-01

    It has been reported that lateral meniscus tears, including posterior horn tears, stable radial flap tears, or peripheral or posterior third tears that are combined with an Anterior Cruciate Ligament (ACL) injury can be treated with being left in situ. However, our experience has shown that the tear patterns are not so simple. They can show complex configurations and the inner side can be lost in chronic cases. Regarding the repair technique, there has been some controversy concerning the follow up results with repair devices and reduction is difficult using these devices if the inner side is non-viable or lost. If the tear involves whole width of bony insertion, it is believed that the meniscal function would be lost, particularly because the anatomic configuration is different in this area. In cases of chronic inner loss types, the meniscus was repaired using a side to side repair or pull out repair technique. Complete healing was achieved using this technique in some patients. Conclusively, Posterior Lateral Meniscus Root Tear (PLMRT) must be managed with different method with tears of other areas because the tear configuration is complex than simple looking. PMID:18930402

  6. Design and performance of a fiber bragg grating displacement sensor for movement measurement of tendon and ligament

    NASA Astrophysics Data System (ADS)

    Ren, Liang; Song, Gangbing; Conditt, Michael; Noble, Philip C.; Li, Hongnan

    2007-04-01

    Biomechanical studies often involve measurements of the strains developed in tendons or ligaments in posture or locomotion. Fiber optic sensors present an attractive option for measurement of strains in tendons and ligaments due to their low cost, ease of implementation, and increased accuracy compared to other implantable transducers. A new displacement sensor based on fiber Bragg grating and shape memory alloy technology is proposed for the monitoring of tendon and ligament strains in different postures and in locomotion. After sensor calibration in the laboratory, a comparison test between the fiber sensors and traditional camera displacement sensors was carried out to evaluate the performance of the fiber sensor during application of tension to the Achilles tendon. Additional experiments were performed in cadaver knees to assess the suitability of these fiber sensors for measuring ligament deformation in a variety of simulated postures. The results demonstrate that the proposed fiber Bragg grating sensor is a high-accuracy, easily implantable, and minimally invasive method of measuring tendon and ligament displacement.

  7. The Cellular Biology of Flexor Tendon Adhesion Formation

    PubMed Central

    Wong, Jason K.F.; Lui, Yin H.; Kapacee, Zoher; Kadler, Karl E.; Ferguson, Mark W. J.; McGrouther, Duncan A.

    2009-01-01

    Intrasynovial flexor tendon injuries of the hand can frequently be complicated by tendon adhesions to the surrounding sheath, limiting finger function. We have developed a new tendon injury model in the mouse to investigate the three-dimensional cellular biology of intrasynovial flexor tendon healing and adhesion formation. We investigated the cell biology using markers for inflammation, proliferation, collagen synthesis, apoptosis, and vascularization/myofibroblasts. Quantitative immunohistochemical image analysis and three-dimensional reconstruction with cell mapping was performed on labeled serial sections. Flexor tendon adhesions were also assessed 21 days after wounding using transmission electron microscopy to examine the cell phenotypes in the wound. When the tendon has been immobilized, the mouse can form tendon adhesions in the flexor tendon sheath. The cell biology of tendon healing follows the classic wound healing response of inflammation, proliferation, synthesis, and apoptosis, but the greater activity occurs in the surrounding tissue. Cells that have multiple “fibripositors” and cells with cytoplasmic protrusions that contain multiple large and small diameter fibrils can be found in the wound during collagen synthesis. In conclusion, adhesion formation occurs due to scarring between two damaged surfaces. The mouse model for flexor tendon injury represents a new platform to study adhesion formation that is genetically tractable. PMID:19834058

  8. Grasp Assist Device with Shared Tendon Actuator Assembly

    NASA Technical Reports Server (NTRS)

    Ihrke, Chris A. (Inventor); Bergelin, Bryan J. (Inventor); Bridgwater, Lyndon (Inventor)

    2015-01-01

    A grasp assist device includes a glove with first and second tendon-driven fingers, a tendon, and a sleeve with a shared tendon actuator assembly. Tendon ends are connected to the respective first and second fingers. The actuator assembly includes a drive assembly having a drive axis and a tendon hook. The tendon hook, which defines an arcuate surface slot, is linearly translatable along the drive axis via the drive assembly, e.g., a servo motor thereof. The flexible tendon is routed through the surface slot such that the surface slot divides the flexible tendon into two portions each terminating in a respective one of the first and second ends. The drive assembly may include a ball screw and nut. An end cap of the actuator assembly may define two channels through which the respective tendon portions pass. The servo motor may be positioned off-axis with respect to the drive axis. XXXX addresses some of the limitations present in the prior art approaches noted above. The grasp assist device includes a glove and a sleeve, which may be worn on a respective hand and forearm of an operator. Linear actuators supported within the sleeve provide tension to flexible tendons, which in turn are connected to the fingers and/or thumb of a glove. The selective tensioning of the tendons improves the operator's grasp strength, and may also facilitate rehabilitation from an injury. It is recognized herein that existing tendon-driven grasp assist devices have certain performance limitations. For example, some designs may require actuator over sizing in order to provide a sufficient amount of actuator travel for applying necessary amounts of tension to a given tendon, e.g., to fully close a finger of a hand wearing the glove into a desired grasp pose. Substantial increases in both size and

  9. Crimp morphology in relaxed and stretched rat Achilles tendon.

    PubMed

    Franchi, Marco; Fini, Milena; Quaranta, Marilisa; De Pasquale, Viviana; Raspanti, Mario; Giavaresi, Gianluca; Ottani, Vittoria; Ruggeri, Alessandro

    2007-01-01

    Fibrous extracellular matrix of tendon is considered to be an inextensible anatomical structure consisting of type I collagen fibrils arranged in parallel bundles. Under polarized light microscopy the collagen fibre bundles appear crimped with alternating dark and light transverse bands. This study describes the ultrastructure of the collagen fibrils in crimps of both relaxed and in vivo stretched rat Achilles tendon. Under polarized light microscopy crimps of relaxed Achilles tendons appear as isosceles or scalene triangles of different size. Tendon crimps observed via SEM and TEM show the single collagen fibrils that suddenly change their direction containing knots. The fibrils appear partially squeezed in the knots, bent on the same plane like bayonets, or twisted and bent. Moreover some of them lose their D-period, revealing their microfibrillar component. These particular aspects of collagen fibrils inside each tendon crimp have been termed 'fibrillar crimps' and may fulfil the same functional role. When tendon is physiologically stretched in vivo the tendon crimps decrease in number (46.7%) (P<0.01) and appear more flattened with an increase in the crimp top angle (165 degrees in stretched tendons vs. 148 degrees in relaxed tendons, P<0.005). Under SEM and TEM, the 'fibrillar crimps' are still present, never losing their structural identity in straightened collagen fibril bundles of stretched tendons even where tendon crimps are not detectable. These data suggest that the 'fibrillar crimp' may be the true structural component of the tendon crimp acting as a shock absorber during physiological stretching of Achilles tendon. PMID:17229278

  10. Chronic Achilles Tendon Rupture Reconstructed With Achilles Tendon Allograft and Xenograft Combination.

    PubMed

    Hollawell, Shane; Baione, William

    2015-01-01

    More than 20% of acute Achilles tendon injuries are misdiagnosed, leading to chronic or neglected ruptures. Some controversy exists regarding how to best manage an acute Achilles tendon rupture. However, a general consensus has been reached that chronic rupture with ?3 cm of separation is associated with functional morbidity and, therefore, should be managed operatively. It has been demonstrated that the functional outcomes of surgically treated Achilles ruptures are superior to the nonoperative outcomes in a chronic setting. In the present report, we reviewed 4 patients with chronic Achilles tendon ruptures that were successfully treated with an Achilles tendon interposition allograft and simultaneous augmentation with a xenograft. The median duration of rupture was 11 (range 8 to 16) weeks, the median gap between the proximal and distal segments of the tendon was 4.75 (range 3.5 to 6) cm, and the patients were able to return pain-free to all preinjury activities at a median of 14.5 (range 13.8 to 15.5) weeks, without the need for tendon transfer, lengthening, or additional intervention. The median duration of follow up was 37.25 (range 15.25 to 51.5) months, at which point the mean Foot and Ankle Outcomes Instrument core scale score was 97 ± 1 (mean normative score 53 ± 1), and the Foot and Ankle Outcomes Instrument shoe comfort core scale score was 100 ± 0 (mean normative score 59 ± 0). The combined Achilles allograft plus xenograft augmentation technique appears to be a reasonable option for the surgical treatment of chronic Achilles tendon rupture. PMID:25488191

  11. Influence of nanofibers on growth and gene expression of human tendon derived fibroblast

    PubMed Central

    2010-01-01

    Background Rotator cuff tears are a common and frequent lesion especially in older patients. The mechanisms of tendon repair are not fully understood. Common therapy options for tendon repair include mini-open or arthroscopic surgery. The use of growth factors in experimental studies is mentioned in the literature. Nanofiber scaffolds, which provide several criteria for the healing process, might be a suitable therapy option for operative treatment. The aim of this study was to explore the effects of nanofiber scaffolds on human tendon derived fibroblasts (TDF's), as well as the gene expression and matrix deposition of these fibroblasts. Methods Nanofibers composed of PLLA and PLLA/Col-I were seeded with human tendon derived fibroblasts and cultivated over a period of 22 days under growth-inductive conditions, and analyzed during the course of culture, with respect to gene expression of different extra cellular matrix components such as collagens, bigylcan and decorin. Furthermore, we measured cell densities and proliferation by using fluorescene microscopy. Results PLLA nanofibers possessed a growth inhibitory effect on TDF's. Furthermore, no meaningful influence on the gene expression of collagen I, collagen III and decorin could be observed, while the expression of collagen X increased during the course of cultivation. On the other hand, PLLA/Col-I blend nanofibers had no negative influence on the growth of TDF's. Furthermore, blending PLLA nanofibers with collagen had a positive effect on the gene expression of collagen I, III, X and decorin. Here, gene expression indicated that focal adherence kinases might be involved. Conclusion This study indicates that the use of nanofibers influence expression of genes associated with the extra cellular matrix formation. The composition of the nanofibers plays a critical role. While PLLA/Col-I blend nanofibers enhance the collagen I and III formation, their expression on PLLA nanofibers was more comparable to controls. However, irrespective of the chemical composition of the fibres, the collagen deposition was altered, an effect which might be associated with a decreased expression of biglycanes. PMID:20163724

  12. Bi-fluid and neoclassical effect on a Double-Tearing mode in Tore Supra

    SciTech Connect

    Maget, Patrick Garbet, Xavier; Février, Olivier; Ségui, Jean-Luc; Lütjens, Hinrich; Luciani, Jean-François

    2014-06-15

    Tearing modes associated to hollow current profiles are prone to grow in moderate performance plasmas and often constrain the realization of non-inductive discharges in the Tore Supra tokamak, where long pulse duration is performed using Lower Hybrid waves for providing most of the plasma current. The prediction of MHD boundaries in such scenarios is complicated by the importance of diamagnetic effects, combined with curvature stabilization, which determine the stability of these modes. We show that diamagnetic effects, as well as neoclassical forces, are playing a key role in the linear and nonlinear regimes of Double-Tearing Modes on q?=?5/3 and q?=?2 in these experimental conditions. Detailed comparison with experimental measurements, combined with a scaling in plasma resistivity, give constraints about the experimental equilibrium. Resistive-Interchange Modes destabilized by diamagnetic rotation could also play a role in degrading the energy confinement in the negative magnetic shear region.

  13. Numerical study on the influence of electron cyclotron current drive on tearing mode

    SciTech Connect

    Chen, Long; Liu, Jinyuan; Mao, Aohua; Sun, Jizhong; Duan, Ping

    2014-10-15

    Controlling tearing modes by localized current drive is explored by using numerical simulation with a set of compressible magnetohydrodynamics equations. By examining the effects of different characteristics of driven current, such as density distribution, duration time, and deposition location, it is found that a driven current with larger magnitude and more focused deposition region shows a better suppression effect on the tearing modes. Meanwhile destabilizing effects are also observed when a driven current over a certain magnitude is applied continuously. In comparison with those on the X-point of the magnetic island, the results are better when the current deposition is targeted on the O-point. In addition, the timing control of the current deposition will be also addressed.

  14. Bi-fluid and neoclassical effect on a Double-Tearing mode in Tore Supra

    NASA Astrophysics Data System (ADS)

    Maget, Patrick; Lütjens, Hinrich; Luciani, Jean-François; Garbet, Xavier; Février, Olivier; Ségui, Jean-Luc

    2014-06-01

    Tearing modes associated to hollow current profiles are prone to grow in moderate performance plasmas and often constrain the realization of non-inductive discharges in the Tore Supra tokamak, where long pulse duration is performed using Lower Hybrid waves for providing most of the plasma current. The prediction of MHD boundaries in such scenarios is complicated by the importance of diamagnetic effects, combined with curvature stabilization, which determine the stability of these modes. We show that diamagnetic effects, as well as neoclassical forces, are playing a key role in the linear and nonlinear regimes of Double-Tearing Modes on q = 5/3 and q = 2 in these experimental conditions. Detailed comparison with experimental measurements, combined with a scaling in plasma resistivity, give constraints about the experimental equilibrium. Resistive-Interchange Modes destabilized by diamagnetic rotation could also play a role in degrading the energy confinement in the negative magnetic shear region.

  15. Surgical Treatment of Combined Posterior Root Tears of the Lateral Meniscus and ACL Tears

    PubMed Central

    Pan, Fengyu; Hua, Shan; Ma, Zhuang

    2015-01-01

    Background The treatment of anterior cruciate ligament (ACL) rupture complicated with posterior lateral meniscus root (PLMR) tears remains controversial. The goal of this study was to evaluate clinical outcomes of PLMR tear refixation versus left untreated at the time of reconstruction. Material/Methods From August 2001 to January 2012, 31 patients who undergone repair of PLMR tears were evaluated and compared with a matched control group with untreated PLMR tears. Clinical evaluation consisted of the Lysholm scale, subjective International Knee Documentation Committee (IKDC) questionnaires, and radiographic evaluation with MRI. Results Regarding to the Lysholm score and the subjective questionnaire score, there were no statistical difference between the 2 groups. However, patients after operative treatment reach higher functional scores and lower rates of osteoarthritis (normal: group A, 80%, and group B, 48%, respectively) with statistical significance (P<0.05) compared to the matched control group. Conclusions Surgical and conservative treatment of the PLMR can both effectively improve knee function. However, a tendency towards higher functional scores and lower rates of osteoarthritis for patients with operative treatment was observed. PMID:25959903

  16. Nonlinear growth of strongly unstable tearing modes

    SciTech Connect

    Waelbroeck, F.L.

    1993-11-01

    Rutherford`s theory of the tearing instability is extended to cases where current nonlinearities are important, such as long wavelength modes in current slabs and the m = 1 instability in tokamaks with moderately large aspect-ratios. Of particular interest is the possibility that the associated magnetic islands, as a result of secondary instabilities, have a singular response to the Ohmic diffusion of the current. A family of islands is used to test this possibility; it is found that the response remains bounded.

  17. In Vivo Evaluation of Adipose-Derived Stromal Cells Delivered with a Nanofiber Scaffold for Tendon-to-Bone Repair.

    PubMed

    Lipner, Justin; Shen, Hua; Cavinatto, Leonardo; Liu, Wenying; Havlioglu, Necat; Xia, Younan; Galatz, Leesa M; Thomopoulos, Stavros

    2015-11-01

    Rotator cuff tears are common and cause a great deal of lost productivity, pain, and disability. Tears are typically repaired by suturing the tendon back to its bony attachment. Unfortunately, the structural (e.g., aligned collagen) and compositional (e.g., a gradient in mineral) elements that produce a robust attachment in the healthy tissue are not regenerated during healing, and the repair is prone to failure. Two features of the failed healing response are deposition of poorly aligned scar tissue and loss of bone at the repair site. Therefore, the objective of the current study was to improve tendon-to-bone healing by promoting aligned collagen deposition and increased bone formation using a biomimetic scaffold seeded with pluripotent cells. An aligned nanofibrous poly(lactic-co-glycolic acid) scaffold with a gradient in mineral content was seeded with adipose-derived stromal cells (ASCs) and implanted at the repair site of a rat rotator cuff model. In one group, cells were transduced with the osteogenic factor bone morphogenetic protein 2 (BMP2). The healing response was examined in four groups (suture only, acellular scaffold, cellular scaffold, and cellular BMP2 scaffold) using histologic, bone morphology, and biomechanical outcomes at 14, 28, and 56 days. Histologically, the healing interface was dominated by a fibrovascular scar response in all groups. The acellular scaffold group showed a delayed healing response compared to the other groups. When examining bone morphology parameters, bone loss was evident in the cellular BMP2 group compared to other groups at 28 days. When examining repair-site mechanical properties, strength and modulus were decreased in the cellular BMP2 groups compared to other groups at 28 and 56 days. These results indicated that tendon-to-bone healing in this animal model was dominated by scar formation, preventing any positive effects of the implanted biomimetic scaffold. Furthermore, cells transduced with the osteogenic factor BMP2 led to impaired healing, suggesting that this growth factor should not be used in the tendon-to-bone repair setting. PMID:26414599

  18. Increased unilateral tendon stiffness and its effect on gait 2-6 years after Achilles tendon rupture.

    PubMed

    Agres, A N; Duda, G N; Gehlen, T J; Arampatzis, A; Taylor, W R; Manegold, S

    2015-12-01

    Achilles tendon rupture (ATR) alters tissue composition, which may affect long-term tendon mechanics and ankle function during movement. However, a relationship between Achilles tendon (AT) properties and ankle joint function during gait remains unclear. The primary hypotheses were that (a) post-ATR tendon stiffness and length differ from the noninjured contralateral side and that (b) intra-patient asymmetries in AT properties correlate to ankle function asymmetries during gait, determined by ankle angles and moments. Ultrasonography and dynamometry were used to assess AT tendon stiffness, strain, elongation, and rest length in both limbs of 20 ATR patients 2-6 years after repair. Three-dimensional ankle angles and moments were determined using gait analysis. Injured tendons exhibited increased stiffness, rest length, and altered kinematics, with higher dorsiflexion and eversion, and lower plantarflexion and inversion. Intra-patient tendon stiffness and tendon length ratios were negatively correlated to intra-patient ratios of the maximum plantarflexion moment and maximum dorsiflexion angle, respectively. These results suggest that after surgical ATR repair, higher AT stiffness, but not a longer AT, may contribute to deficits in plantarflexion moment generation. These data further support the claim that post-ATR tendon regeneration results in the production of a tissue that is functionally different than noninjured tendon. PMID:25902929

  19. Augmented Repair of Acute Achilles Tendon Rupture Using an Allograft Tendon Weaving Technique.

    PubMed

    Huang, Xiaowei; Huang, Gan; Ji, Ying; Ao, Rong Guang; Yu, Baoqing; Zhu, Ya Long

    2015-01-01

    Achilles tendon rupture is a common injury, especially in those who are physically active. Although open surgery is a widely used option for the treatment of acute Achilles tendon rupture, the optimal treatment is still disputed. In our study, 59 patients with unilateral, closed, acute rupture of the Achilles tendon were treated by open surgery using an allograft weave to augment the repair. All the surgeries were performed within 1 to 4 days after injury. The mean American Orthopaedic Foot and Ankle Society ankle-hindfoot score was recorded as 91.20 (range 88 to 95), 95.34 (range 92 to 98), and 98.27 (range 97 to 99) at the 3-, 6-, and 12-month follow-up visit, respectively. At the final follow-up visit, the mean difference between the mid-calf circumference of the injured and uninjured legs was 0.19 (range -0.03 to 1.50) cm (p = .43). At the final follow-up visit, the mean difference between the vertical distances from the plantar surface of the heel to the ground for the injured and uninjured lower extremities was 0.44 (range -0.03 to 0.5) cm (p = .17). Augmented repair using the allograft tendon weaving technique provided satisfactory tendon strength and functional outcomes and a timely return to the patients' activities. PMID:26015299

  20. A Tendon Cell Specific RNAi Screen Reveals Novel Candidates Essential for Muscle Tendon Interaction

    PubMed Central

    Tiwari, Prabhat; Malhotra, Vivek; VijayRaghavan, K.

    2015-01-01

    Tendons are fibrous connective tissue which connect muscles to the skeletal elements thus acting as passive transmitters of force during locomotion and provide appropriate body posture. Tendon-derived cues, albeit poorly understood, are necessary for proper muscle guidance and attachment during development. In the present study, we used dorsal longitudinal muscles of Drosophila and their tendon attachment sites to unravel the molecular nature of interactions between muscles and tendons. We performed a genetic screen using RNAi-mediated knockdown in tendon cells to find out molecular players involved in the formation and maintenance of myotendinous junction and found 21 candidates out of 2507 RNAi lines screened. Of these, 19 were novel molecules in context of myotendinous system. Integrin-?PS and Talin, picked as candidates in this screen, are known to play important role in the cell-cell interaction and myotendinous junction formation validating our screen. We have found candidates with enzymatic function, transcription activity, cell adhesion, protein folding and intracellular transport function. Tango1, an ER exit protein involved in collagen secretion was identified as a candidate molecule involved in the formation of myotendinous junction. Tango1 knockdown was found to affect development of muscle attachment sites and formation of myotendinous junction. Tango1 was also found to be involved in secretion of Viking (Collagen type IV) and BM-40 from hemocytes and fat cells. PMID:26488612

  1. [Animal experiment study of healing of the sutured flexor tendon].

    PubMed

    Martini, A K; Blimke, B

    1992-01-01

    The purpose of the present study was to determine whether tendons contain intrinsic cells capable of repair. To accomplish this, rabbit flexor tendons were exposed microsurgically, cut through, resutured and transferred as free transplant into the knee-joint. Immobilisation of the knee-joint will cause progressive formation of adhesions permitting neovascularisation of the transplant. Both is not observed when sutured flexor tendons were put in a knee articulation with full range of joint motion. Transmission electron micrography revealed up to 8 weeks after implantation vital cells and incidences of collagen neosynthesis independently whether adhesions existed or not. Histologically intrinsic repair was confirmed in mobile transplants and mainly initiated by cells of the visceral synovial sheet which form an anatomic-surgical unity with the tendon. In conclusion the importance of the synovial fluid for the tendon nutrition is underlined by the fact that an intrinsic healing of flexor tendon is possible without formation of adhesions. PMID:1582849

  2. Exploring the application of stem cells in tendon repair and regeneration.

    E-print Network

    Ahmad, Z.; Wardale, J.; Brooks, R.; Henson, F.; Noorani, A.; Rushton, N.

    2012-07-28

    clinical studies met the inclusion criteria. Preclinical studies have shown that stem cells are able to survive and differentiate into tendon cells when placed into a new tendon environment, leading to regeneration and biomechanical benefit to the tendon...

  3. Anterior cruciate ligament reconstruction with allograft tendons.

    PubMed

    Strickland, Sabrina M; MacGillivray, John D; Warren, Russell F

    2003-01-01

    Allograft tissue allows reconstruction of the ACL without the donor site morbidity that can be caused by autograft harvesting. Patients who must kneel as a part of their occupation or chosen sport are particularly good candidates for allograft reconstruction. Patients over 45 years of age and those requiring revision ACL surgery can also benefit from the use and availability of allograft tendons. In some cases, patients or surgeons may opt for allograft tendons to maximize the result or morbidity ratio. Despite advances in cadaver screening and graft preparation, there remain risks of disease transmission and joint infection after allograft implantation. Detailed explanation and informed consent is vitally important in cases in which allograft tissue is used. PMID:12735200

  4. A 3-Dimensional Anatomic Study of the Distal Biceps Tendon

    PubMed Central

    Walton, Christine; Li, Zhi; Pennings, Amanda; Agur, Anne; Elmaraghy, Amr

    2015-01-01

    Background Complete rupture of the distal biceps tendon from its osseous attachment is most often treated with operative intervention. Knowledge of the overall tendon morphology as well as the orientation of the collagenous fibers throughout the musculotendinous junction are key to intraoperative decision making and surgical technique in both the acute and chronic setting. Unfortunately, there is little information available in the literature. Purpose To comprehensively describe the morphology of the distal biceps tendon. Study Design Descriptive laboratory study. Methods The distal biceps terminal musculature, musculotendinous junction, and tendon were digitized in 10 cadaveric specimens and data reconstructed using 3-dimensional modeling. Results The average length, width, and thickness of the external distal biceps tendon were found to be 63.0, 6.0, and 3.0 mm, respectively. A unique expansion of the tendon fibers within the distal muscle was characterized, creating a thick collagenous network along the central component between the long and short heads. Conclusion This study documents the morphologic parameters of the native distal biceps tendon. Reconstruction may be necessary, especially in chronic distal biceps tendon ruptures, if the remaining tendon morphology is significantly compromised compared with the native distal biceps tendon. Knowledge of normal anatomical distal biceps tendon parameters may also guide the selection of a substitute graft with similar morphological characteristics. Clinical Relevance A thorough description of distal biceps tendon morphology is important to guide intraoperative decision making between primary repair and reconstruction and to better select the most appropriate graft. The detailed description of the tendinous expansion into the muscle may provide insight into better graft-weaving and suture-grasping techniques to maximize proximal graft incorporation. PMID:26665092

  5. SLAP tear associated with a minimally displaced proximal humerus fracture.

    PubMed

    Kendall, Corey B; Tanner, Stephanie L; Tolan, Stefan J

    2007-12-01

    Nondisplaced proximal humerus fracture may be associated with soft tissue injury. This case report examines 2 cases of superior labral anterior-posterior (SLAP) tears in association with nondisplaced fractures of the proximal humerus. In the first case, the patient fell from a jet ski, causing a traction injury to his arm. A greater tuberosity fracture was identified. Magnetic resonance imaging (MRI) did not reveal a definitive labral tear. After conservative management had failed, a type IV SLAP tear and a small rotator cuff tear were arthroscopically identified and repaired. In the second case, a power company lineman fell from a lift and attempted to hold on with his dominant arm. A nondisplaced greater tuberosity and a surgical neck fracture were discovered. MR arthrography revealed no evidence of SLAP tear. Four months after injury, a type II SLAP tear was arthroscopically identified and repaired. In these 2 cases, the presence of the fracture likely slowed operative intervention because pain was attributed to the fracture itself, and not to the SLAP tear. If patients do not follow the usual course of improvement after a proximal humerus fracture from a superior traction mechanism, consideration should be given to associated superior labral tears that may require surgical intervention. PMID:18063188

  6. Reasoning about Card Tears and Transactions in Java Card

    E-print Network

    Hubbers, Engelbert

    Reasoning about Card Tears and Transactions in Java Card Engelbert Hubbers and Erik Poll SoS Group dialect Java Card for programming smartcards contains some features which do not exist in Java. Java Card power to a smartcard can suddenly be in- terrupted by a so-called card tear, by someone removing

  7. Quadriceps Tendon Rupture due to Postepileptic Convulsion

    PubMed Central

    Erkut, Adem; Guvercin, Yilmaz; Sahin, Rifat; Keskin, Davut

    2014-01-01

    We present a case of quadriceps tendon (QT) rupture. QT ruptures can occur in all ages. The cause is mostly traumatic in origin. Spontaneous ruptures that are thought to result from predisposing conditions are rare. Post-convulsion QT ruptures lacking traumas in their history can be overlooked in clinical examinations. This should be born in mind by the attending physician, as early diagnosis and treatment of the condition can lead to satisfactory outcomes. PMID:24944977

  8. Subacromial volume and rotator cuff tears

    PubMed Central

    Yi, Anthony; Avramis, Ioannis A; Argintar, Evan H; White, Eric R; Villacis, Diego C; Hatch III, George F Rick

    2015-01-01

    Background: Rotator cuff pathology occurs commonly and its cause is likely multifocal in origin. The development and progression of rotator cuff injury, especially in relation to extrinsic shoulder compression, remain unclear. Traditionally, certain acromial morphologies have been thought to contribute to rotator cuff injury by physically decreasing the subacromial space. The relationship between subacromial space volume and rotator cuff tears (RCT) has, however, never been experimentally confirmed. In this study, we retrospectively compared a control patient population to patients with partial or complete RCTs in an attempt to quantify the relationship between subacromial volume and tear type. Materials and Methods: We retrospectively identified a total of 46 eligible patients who each had shoulder magnetic resonance imaging (MRI) performed from January to December of 2008. These patients were stratified into control, partial RCT, and full-thickness RCT groups. Subacromial volume was estimated for each patient by averaging five sequential MRI measurements of subacromial cross-sectional areas. These volumes were compared between control and experimental groups using the Student's t-test. Results: With the numbers available, there was no statistically significant difference in subacromial volume measured between: the control group and patients diagnosed partial RCT (P > 0.339), the control group and patients with complete RCTs (P > 0.431). Conclusion: We conclude that subacromial volumes cannot be reliably used to predict RCT type. PMID:26015629

  9. Rotator cuff tears in the throwing athlete.

    PubMed

    Shaffer, Benjamin; Huttman, Daniel

    2014-06-01

    Tears of the rotator cuff, both partial, and less commonly, full thickness, are relatively common in the throwing athlete. The rotator cuff is subjected to enormous stresses during repetitive overhead activity. The supraphysiological strains, especially when combined with pathology elsewhere in the kinetic chain, can lead to compromise of the cuff fabric, most commonly on the undersurface where tensile overload occurs. Exacerbation by a tight posterior capsular, anterior instability, and internal impingement render the cuff progressively compromised, with intrinsic shear stresses and undersurface fiber failure. Advances in imaging technology, including contrast magnetic resonance imaging, dynamic ultrasound, and arthroscopic visualization have enhanced our understanding of cuff pathology in this athletic population. Unfortunately, this has not yet translated into how to best approach these athletes to return them to their previous level of activity. Nonoperative management remains the mainstay for most throwers, with arthroscopic debridement an effective surgical option for those with refractory symptoms. Despite technological advances in cuff repair in the general population, comparable outcomes have not been achieved in high-level throwers. Widespread appreciation that securing the cuff operatively will likely end an athletes' throwing career has led to adopting a surgical approach that emphasizes debridement over repair for nearly all partial and full-thickness tears. Whether advances in surgical technique will ultimately permit definitive and lasting repairs that allow overhead throwers to return to their previous level of sports remains unknown at this time. PMID:24787724

  10. Low level laser therapy in healing tendon

    NASA Astrophysics Data System (ADS)

    Carvalho, P. T. C.; Batista, Cheila O. C.; Fabíola, C.

    2005-11-01

    This study aims to verify the effects of AsGa Laser in the scarring of tendon lesion in rats with low nourishment condition and to analyze the ideal light density by means of histopathologic findings highlighted by light microscopy. After the proposed nutritional condition was verified the animals were divided into 3 groups denominated as follows: GI control group, GII laser 1 J/sq.cm. and GIII laser 4 J/sq.cm. The lesions were induced by means of routine surgical process for tendon exposure: There was a crushing process with Allis pincers followed by saturated incision. The data obtained in relation to the amount of macrophage, leukocyte, fibroblast, vessel neoformation, fibrosis and collagen were submitted to parametric statistic procedures of variance analysis and "Tukey" Test and the result obtained was p < 0,05. According to the obtained results it can be concluded that low power laser therapy proved to be efficient in tendon repairing even though the animals suffered from malnutrition as well as the 1 J energy density proved to be more efficient in this case.

  11. The intercalated tendon graft for treatment of extensor pollicis longus tendon rupture.

    PubMed

    Magnell, T D; Pochron, M D; Condit, D P

    1988-01-01

    Twenty-one patients with ruptures of the extensor pollicis longus tendon were treated with a subcutaneously placed free tendon graft. The repair was performed a mean of 6 weeks after rupture, range from 1 to 21 weeks. Data was collected on 19 of these patients, with a mean follow-up of 30 months, range from 6 to 124 months. Near uniform satisfaction was reported. The mean loss of interphalangeal joint extension and flexion and combined metacarpophalangeal-interphalangeal joint motion was 6 degrees, 3 degrees, and 10 degrees, respectively. The mean loss of pinch strength was 7%. All patients were able to elevate their thumbs to the level of the palm. This is a simple, reliable, and effective procedure that avoids the use of an adjacent motor-tendon unit. Muscle contracture appears reversible and this procedure may be used successfully even when treatment has been delayed. PMID:3351213

  12. Biological Augmentation of Flexor Tendon Repair: A Challenging Cellular Landscape.

    PubMed

    Loiselle, Alayna E; Kelly, Meghan; Hammert, Warren C

    2016-01-01

    Advances in surgical technique and rehabilitation have transformed zone II flexor tendon injuries from an inoperable no-man's land to a standard surgical procedure. Despite these advances, many patients develop substantial range of motion-limiting adhesions after primary flexor tendon repair. These suboptimal outcomes may benefit from biologic augmentation or intervention during the flexor tendon healing process. However, there is no consensus biological approach to promote satisfactory flexor tendon healing; we propose that insufficient understanding of the complex cellular milieu in the healing tendon has hindered the development of successful therapies. This article reviews recent advances in our understanding of the cellular components of flexor tendon healing and adhesion formation, including resident tendon cells, synovial sheath, macrophages, and bone marrow-derived cells. In addition, it examines molecular approaches that have been used in translational animal models to improve flexor tendon healing and gliding function, with a specific focus on progress made using murine models of healing. This information highlights the importance of understanding and potentially exploiting the heterogeneity of the cellular environment during flexor tendon healing, to define rational therapeutic approaches to improve healing outcomes. PMID:26652792

  13. Complications of Tendon Surgery in the Foot and Ankle.

    PubMed

    Barp, Eric A; Erickson, John G

    2016-01-01

    This article discusses four subsets of patients that have an increased risk of complications from tendon surgery in the foot and ankle: smokers, diabetics, and patients with peroneal or Achilles tendon pathology. Very little has been published on the complications of other tendon surgeries in the foot and ankle other than Achilles tendon repair. Data can be extrapolated from the general orthopedic literature and animal studies to help guide therapy and treatment options. The foot and ankle surgeon must take into account the entirety of the history and physical examination to develop a treatment plan that optimizes each patient's chance for a complication-free recovery. PMID:26590733

  14. A conceptual framework for computational models of Achilles tendon homeostasis.

    PubMed

    Smith, David W; Rubenson, Jonas; Lloyd, David; Zheng, Minghao; Fernandez, Justin; Besier, Thor; Xu, Jiake; Gardiner, Bruce S

    2013-01-01

    Computational modeling of tendon lags the development of computational models for other tissues. A major bottleneck in the development of realistic computational models for Achilles tendon is the absence of detailed conceptual and theoretical models as to how the tissue actually functions. Without the conceptual models to provide a theoretical framework to guide the development and integration of multiscale computational models, modeling of the Achilles tendon to date has tended to be piecemeal and focused on specific mechanical or biochemical issues. In this paper, we present a new conceptual model of Achilles tendon tissue homeostasis, and discuss this model in terms of existing computational models of tendon. This approach has the benefits of structuring the research on relevant computational modeling to date, while allowing us to identify new computational models requiring development. The critically important functional issue for tendon is that it is continually damaged during use and so has to be repaired. From this follows the centrally important issue of homeostasis of the load carrying collagen fibrils within the collagen fibers of the Achilles tendon. Collagen fibrils may be damaged mechanically-by loading, or damaged biochemically-by proteases. Upon reviewing existing computational models within this conceptual framework of the Achilles tendon structure and function, we demonstrate that a great deal of theoretical and experimental research remains to be done before there are reliably predictive multiscale computational model of Achilles tendon in health and disease. PMID:23757159

  15. Tendon synovial cells secrete fibronectin in vivo and in vitro

    SciTech Connect

    Banes, A.J.; Link, G.W.; Bevin, A.G.; Peterson, H.D.; Gillespie, Y.; Bynum, D.; Watts, S.; Dahners, L.

    1988-01-01

    The chemistry and cell biology of the tendon have been largely overlooked due to the emphasis on collagen, the principle structural component of the tendon. The tendon must not only transmit the force of muscle contraction to bone to effect movement, but it must also glide simultaneously over extratendonous tissues. Fibronectin is classified as a cell attachment molecule that induces cell spreading and adhesion to substratum. The external surface of intact avian flexor tendon stained positively with antibody to cellular fibronectin. However, if the surface synovial cells were first removed with collagenase, no positive reaction with antifibronectin antibody was detected. Analysis of immunologically stained frozen sections of tendon also revealed fibronectin at the tendon synovium, but little was associated with cells internal in tendon. The staining pattern with isolated, cultured synovial cells and fibroblasts from the tendon interior substantiated the histological observations. Analysis of polyacrylamide gel profiles of /sup 35/S-methionine-labeled proteins synthesized by synovial cells and internal fibroblasts indicated that fibronectin was synthesized principally by synovial cells. Fibronectin at the tendon surface may play a role in cell attachment to prevent cell removal by the friction of gliding. Alternatively, fibronectin, with its binding sites for hyaluronic acid and collagen, may act as a complex for boundary lubrication.

  16. Biology and augmentation of tendon-bone insertion repair

    PubMed Central

    2010-01-01

    Surgical reattachment of tendon and bone such as in rotator cuff repair, patellar-patella tendon repair and anterior cruciate ligament (ACL) reconstruction often fails due to the failure of regeneration of the specialized tissue ("enthesis") which connects tendon to bone. Tendon-to-bone healing taking place between inhomogenous tissues is a slow process compared to healing within homogenous tissue, such as tendon to tendon or bone to bone healing. Therefore special attention must be paid to augment tendon to bone insertion (TBI) healing. Apart from surgical fixation, biological and biophysical interventions have been studied aiming at regeneration of TBI healing complex, especially the regeneration of interpositioned fibrocartilage and new bone at the healing junction. This paper described the biology and the factors influencing TBI healing using patella-patellar tendon (PPT) healing and tendon graft to bone tunnel healing in ACL reconstruction as examples. Recent development in the improvement of TBI healing and directions for future studies were also reviewed and discussed. PMID:20727196

  17. Impact of oestrogen deficiency and aging on tendon: concise review

    PubMed Central

    Frizziero, Antonio; Vittadini, Filippo; Gasparre, Giuseppe; Masiero, Stefano

    2014-01-01

    Summary The knowledge about tendons and tenocyte biological behaviour during aging and, especially, oestrogen deficiency is limited. Women differ from men with regard to muscle and tendon, most likely due to differences in sex hormones activity and tissue response. To-date the interest in metabolic factors that may induce tendon disorders is growing. The aim of this paper is to elucidate the current findings in the correlation between oestrogen deficiency, aging and tendon pathology and to encourage future researches to ameliorate assessment and management of tendinopathies in postmenopausal women. PMID:25489550

  18. Reconstruction of a ruptured patellar tendon using ipsilateral semitendinosus and gracilis tendons with preserved distal insertions: two case reports

    PubMed Central

    2013-01-01

    Background Acute patellar tendon ruptures with poor tissue quality. Ruptures that have been neglected are difficult to repair. Several surgical techniques for the repair of the patellar tendon have been reported, however, these techniques remain difficult because of contractures, adhesions, and atrophy of the quadriceps muscle after surgery. Case presentation We report the cases of 2 Japanese patients (Case 1: a 16-year-old male and Case 2: a 43-year-old male) with patellar tendon ruptures who were treated by reconstruction using semitendinosus-gracilis (STG) tendons with preserved distal insertions. Retaining the original insertion of the STG appears to preserve its viability and provide the revascularization necessary to accelerate healing. Both tendons were placed in front of the patella, in a figure-of-eight fashion, providing stability to the patella. Conclusion Both patients recovered near normal strength and stability of the patellar tendon as well as restoration of function after the operation. PMID:24010848

  19. Tear pH, air pollution, and contact lenses

    SciTech Connect

    Andres, S.; Garcia, M.L.; Espina, M.; Valero, J.; Valls, O.

    1988-08-01

    We analyzed the tear pH of a random sample of 100 subjects, divided into 3 groups according to the stability of their precorneal tear film (normal eyes, borderline; and dry eyes). The average pH value obtained was 7.52. The pH for borderline and dry eyes was higher than for normal eyes. The purpose of this study was to determine the influence of air pollution, specifically sulfur dioxide (SO/sub 2/), on the tear pH. We found that air pollution affected the lacrimal pH, which decreased when the atmospheric SO/sub 2/ increased. Finally, we studied the effect of soft contact lens wear on tear pH after 7 days of contact lens adaptation by assessing the tear pH decrease. We took into account the influence of the sex and age of subjects on the results obtained.

  20. Habitual loading results in tendon hypertrophy and increased stiffness of the human patellar tendon.

    PubMed

    Couppé, C; Kongsgaard, M; Aagaard, P; Hansen, P; Bojsen-Moller, J; Kjaer, M; Magnusson, S P

    2008-09-01

    The purpose of this study was to examine patellar tendon (PT) size and mechanical properties in subjects with a side-to-side strength difference of > or =15% due to sport-induced loading. Seven elite fencers and badminton players were included. Cross-sectional area (CSA) of the PT obtained from MRI and ultrasonography-based measurement of tibial and patellar movement together with PT force during isometric contractions were used to estimate mechanical properties of the PT bilaterally. We found that distal tendon and PT, but not mid-tendon, CSA were greater on the lead extremity compared with the nonlead extremity (distal: 139 +/- 11 vs. 116 +/- 7 mm(2); mid-tendon: 85 +/- 5 vs. 77 +/- 3 mm(2); proximal: 106 +/- 7 vs. 83 +/- 4 mm(2); P < 0.05). Distal tendon CSA was greater than proximal and mid-tendon CSA on both the lead and nonlead extremity (P < 0.05). For a given common force, stress was lower on the lead extremity (52.9 +/- 4.8 MPa) compared with the nonlead extremity (66.0 +/- 8.0 MPa; P < 0.05). PT stiffness was also higher in the lead extremity (4,766 +/- 716 N/mm) compared with the nonlead extremity (3,494 +/- 446 N/mm) (P < 0.05), whereas the modulus did not differ (lead 2.27 +/- 0.27 GPa vs. nonlead 2.16 +/- 0.28 GPa) at a common force. These data show that a habitual loading is associated with a significant increase in PT size and mechanical properties. PMID:18556433

  1. Prevalence of rotator cuff tears in operative proximal humerus fractures.

    PubMed

    Choo, Andrew; Sobol, Garret; Maltenfort, Mitchell; Getz, Charles; Abboud, Joseph

    2014-11-01

    Proximal humerus fractures and rotator cuff tears have been shown to have increasing rates with advancing age, theoretically leading to significant overlap in the 2 pathologies. The goal of this study was to examine the prevalence, associated factors, and effect on treatment of rotator cuff tears in surgically treated proximal humerus fractures. A retrospective review was performed of all patients who had surgery for a proximal humerus fracture from January 2007 to June 2012 in the shoulder department of a large academic institution. Patient demographics, the presence and management of rotator cuff tears, and surgical factors were recorded. Regression analysis was performed to determine which factors were associated with rotator cuff tears. This study reviewed 349 fractures in 345 patients. Of these, 30 (8.6%) had concomitant rotator cuff tears. Those with a rotator cuff tear were older (average age, 68.7 vs 63.1 years), were more likely to have had a dislocation (40% vs 12.5%), and were more likely to have undergone subsequent arthroscopic repair or reverse total shoulder arthroplasty than those without a rotator cuff tear. Most (22 of 30) were treated with suture repair at the time of surgery, but 5 patients underwent reverse total shoulder arthroplasty based primarily on the intraoperative finding of a significant rotator cuff tear. A concomitant rotator cuff tear in association with a proximal humerus fracture is relatively common. Rotator cuff tears are associated with older patients and those with a fracture-dislocation. In rare cases, these cases may require the availability of a reverse shoulder prosthesis. PMID:25361372

  2. Repair of Achilles tendon defect with autologous ASCs engineered tendon in a rabbit model.

    PubMed

    Deng, Dan; Wang, Wenbo; Wang, Bin; Zhang, Peihua; Zhou, Guangdong; Zhang, Wen Jie; Cao, Yilin; Liu, Wei

    2014-10-01

    Adipose derived stem cells (ASCs) are an important cell source for tissue regeneration and have been demonstrated the potential of tenogenic differentiation in vitro. This study explored the feasibility of using ASCs for engineered tendon repair in vivo in a rabbit Achilles tendon model. Total 30 rabbits were involved in this study. A composite tendon scaffold composed of an inner part of polyglycolic acid (PGA) unwoven fibers and an outer part of a net knitted with PGA/PLA (polylactic acid) fibers was used to provide mechanical strength. Autologous ASCs were harvested from nuchal subcutaneous adipose tissues and in vitro expanded. The expanded ASCs were harvested and resuspended in culture medium and evenly seeded onto the scaffold in the experimental group, whereas cell-free scaffolds served as the control group. The constructs of both groups were cultured inside a bioreactor under dynamic stretch for 5 weeks. In each of 30 rabbits, a 2 cm defect was created on right side of Achilles tendon followed by the transplantation of a 3 cm cell-seeded scaffold in the experimental group of 15 rabbits, or by the transplantation of a 3 cm cell-free scaffold in the control group of 15 rabbits. Animals were sacrificed at 12, 21 and 45 weeks post-surgery for gross view, histology, and mechanical analysis. The results showed that short term in vitro culture enabled ASCs to produce matrix on the PGA fibers and the constructs showed tensile strength around 50 MPa in both groups (p > 0.05). With the increase of implantation time, cell-seeded constructs gradually form neo-tendon and became more mature at 45 weeks with histological structure similar to that of native tendon and with the presence of bipolar pattern and D-periodic structure of formed collagen fibrils. Additionally, both collagen fibril diameters and tensile strength increased continuously with significant difference among different time points (p < 0.05). In contrast, cell-free constructs failed to form good quality tendon tissue with fibril structure observable only at 45 weeks. There were significant differences in both collagen fibril diameter and tensile strength between two groups at all examined time points (p < 0.05). The results of this study support that ASCs are likely to be a potential cell source for in vivo tendon engineering and regeneration. PMID:25069604

  3. The interfascicular matrix enables fascicle sliding and recovery in tendon, and behaves more elastically in energy storing tendons

    PubMed Central

    Thorpe, Chavaunne T.; Godinho, Marta S.C.; Riley, Graham P.; Birch, Helen L.; Clegg, Peter D.; Screen, Hazel R.C.

    2015-01-01

    While the predominant function of all tendons is to transfer force from muscle to bone and position the limbs, some tendons additionally function as energy stores, reducing the cost of locomotion. Energy storing tendons experience extremely high strains and need to be able to recoil efficiently for maximum energy storage and return. In the equine forelimb, the energy storing superficial digital flexor tendon (SDFT) has much higher failure strains than the positional common digital extensor tendon (CDET). However, we have previously shown that this is not due to differences in the properties of the SDFT and CDET fascicles (the largest tendon subunits). Instead, there is a greater capacity for interfascicular sliding in the SDFT which facilitates the greater extensions in this particular tendon (Thorpe et al., 2012). In the current study, we exposed fascicles and interfascicular matrix (IFM) from the SDFT and CDET to cyclic loading followed by a test to failure. The results show that IFM mechanical behaviour is not a result of irreversible deformation, but the IFM is able to withstand cyclic loading, and is more elastic in the SDFT than in the CDET. We also assessed the effect of ageing on IFM properties, demonstrating that the IFM is less able to resist repetitive loading as it ages, becoming stiffer with increasing age in the SDFT. These results provide further indications that the IFM is important for efficient function in energy storing tendons, and age-related alterations to the IFM may compromise function and predispose older tendons to injury. PMID:25958330

  4. The Effect of Phospholipids (Surfactant) on Adhesion and Biomechanical Properties of Tendon: A Rat Achilles Tendon Repair Model

    PubMed Central

    Dabak, T. Kursat; Sertkaya, Omer; Acar, Nuray; Donmez, B. Ozgur; Ustunel, Ismail

    2015-01-01

    Adhesion of the tendon is a major challenge for the orthopedic surgeon during tendon repair. Manipulation of biological environment is one of the concepts to prevent adhesion. Lots of biochemicals have been studied for this purpose. We aimed to determine the effect of phospholipids on adhesion and biomechanical properties of tendon in an animal tendon repair model. Seventy-two Wistar rats were divided into 4 groups. Achilles tendons of rats were cut and repaired. Phospholipids were applied at two different dosages. Tendon adhesion was determined histopathologically and biomechanical test was performed. At macroscopic evaluation of adhesion, there are statistically significant differences between multiple-dose phospholipid injection group and Control group and also hyaluronic acid group and Control group (p < 0.008). At microscopic evaluation of adhesion, there was no statistically significant difference (p > 0.008). Ultimate strength was highest at hyaluronic acid injection group and lowest at multiple-dose phospholipid injection group. Single-dose phospholipids (surfactant) application may have a beneficial effect on the tendon adhesion. Although multiple applications of phospholipids seem the most effective regime to reduce the tendon adhesion among groups, it deteriorated the biomechanical properties of tendon. PMID:26101776

  5. The interfascicular matrix enables fascicle sliding and recovery in tendon, and behaves more elastically in energy storing tendons.

    PubMed

    Thorpe, Chavaunne T; Godinho, Marta S C; Riley, Graham P; Birch, Helen L; Clegg, Peter D; Screen, Hazel R C

    2015-12-01

    While the predominant function of all tendons is to transfer force from muscle to bone and position the limbs, some tendons additionally function as energy stores, reducing the cost of locomotion. Energy storing tendons experience extremely high strains and need to be able to recoil efficiently for maximum energy storage and return. In the equine forelimb, the energy storing superficial digital flexor tendon (SDFT) has much higher failure strains than the positional common digital extensor tendon (CDET). However, we have previously shown that this is not due to differences in the properties of the SDFT and CDET fascicles (the largest tendon subunits). Instead, there is a greater capacity for interfascicular sliding in the SDFT which facilitates the greater extensions in this particular tendon (Thorpe et al., 2012). In the current study, we exposed fascicles and interfascicular matrix (IFM) from the SDFT and CDET to cyclic loading followed by a test to failure. The results show that IFM mechanical behaviour is not a result of irreversible deformation, but the IFM is able to withstand cyclic loading, and is more elastic in the SDFT than in the CDET. We also assessed the effect of ageing on IFM properties, demonstrating that the IFM is less able to resist repetitive loading as it ages, becoming stiffer with increasing age in the SDFT. These results provide further indications that the IFM is important for efficient function in energy storing tendons, and age-related alterations to the IFM may compromise function and predispose older tendons to injury. PMID:25958330

  6. Effect of acute resistance exercise and sex on human patellar tendon structural and regulatory mRNA expression

    PubMed Central

    Sullivan, Bridget E.; Carroll, Chad C.; Jemiolo, Bozena; Trappe, Scott W.; Magnusson, S. Peter; Døssing, Simon; Kjaer, Michael; Trappe, Todd A.

    2009-01-01

    Tendon is mainly composed of collagen and an aqueous matrix of proteoglycans that are regulated by enzymes called matrix metalloproteinases (MMPs) and tissue inhibitors of metalloproteinases (TIMPs). Although it is known that resistance exercise (RE) and sex influence tendon metabolism and mechanical properties, it is uncertain what structural and regulatory components contribute to these responses. We measured the mRNA expression of tendon's main fibrillar collagens (type I and type III) and the main proteoglycans (decorin, biglycan, fibromodulin, and versican) and the regulatory enzymes MMP-2, MMP-9, MMP-3, and TIMP-1 at rest and after RE. Patellar tendon biopsy samples were taken from six individuals (3 men and 3 women) before and 4 h after a bout of RE and from a another six individuals (3 men and 3 women) before and 24 h after RE. Resting mRNA expression was used for sex comparisons (6 men and 6 women). Collagen type I, collagen type III, and MMP-2 were downregulated (P < 0.05) 4 h after RE but were unchanged (P > 0.05) 24 h after RE. All other genes remained unchanged (P > 0.05) after RE. Women had higher resting mRNA expression (P < 0.05) of collagen type III and a trend (P = 0.08) toward lower resting expression of MMP-3 than men. All other genes were not influenced (P > 0.05) by sex. Acute RE appears to stimulate a change in collagen type I, collagen type III, and MMP-2 gene regulation in the human patellar tendon. Sex influences the structural and regulatory mRNA expression of tendon. PMID:19023016

  7. All-Arthroscopic Suprapectoral Long Head of Biceps Tendon Tenodesis With Interference Screw–Like Tendon Fixation After Modified Lasso-Loop Stitch Tendon Securing

    PubMed Central

    Patzer, Thilo; Kircher, Jörn; Krauspe, Ruediger

    2012-01-01

    Arthroscopic suprapectoral techniques for tenodesis of the long head of the biceps tendon (LHB) are appropriate for the treatment of proximal biceps lesions. Several types of techniques and fixation devices have been described and evaluated in biomechanical studies regarding primary stability. In this technical note, we describe an all-arthroscopic suprapectoral technique using the 6.25-mm Bio-SwiveLock device (Arthrex, Naples, FL) for an interference screw–like bony fixation after having armed the tendon with a lasso-loop stitch. Both the interference screw fixation and securing of the lasso-loop tendon have been well described and approved in biomechanical tests concerning the primary stability. One advantage of this technique performed from the glenohumeral space, in addition to the strong and secure fixation with ingrowth of the tendon in a bony canal, is the avoidance of touching the soft tissue above the bicipital groove, which results in a smooth fitting of the tendon into its natural canal and therefore avoids mechanical irritation of the stump at the rotator interval. In conclusion, the all-arthroscopic suprapectoral LHB tenodesis performed from the glenohumeral space with the modified lasso-loop stitch for securing of the tendon and the 6.25-mm Bio-SwiveLock suture anchor for interference screw–like bony tendon fixation is an appropriate technique for the treatment of LHB-associated lesions. PMID:23766976

  8. Massive cuff tears treated with arthroscopically assisted latissimus dorsi transfer. Surgical technique.

    PubMed

    De Cupis, Vincenzo; De Cupis, Mauro

    2012-04-01

    Latissimus dorsi transfer is our preferred treatment for active disabled patients with a posterosuperior massive cuff tear. We present an arthroscopically assisted technique which avoids an incision through the deltoid obtaining a better and faster clinical outcome. The patient is placed in lateral decubitus. After the arthroscopic evaluation of the lesion through a posterior and a posterolateral portal, with the limb in traction we perform the preparation of the greater tuberosity of the humerus. We place the arm in abduction and internal rotation and we proceed to the harvest of the latissimus dorsi and the tendon preparation by stitching the two sides using very resistant sutures. After restoring limb traction, under arthroscopic visualization, we pass a curved grasper through the posterolateral portal by going to the armpit in the space between the teres minor and the posterior deltoid. Once the grasper has exited the access at the level of the axilla we fix two drainage transparent tubes, each with a wire inside, and, withdrawing it back, we shuttle the two tubes in the subacromial space. After tensioning the suture wires from the anterior portals these are assembled in a knotless anchor of 5.5 mm that we place in the prepared site on the greater tuberosity of the humerus. A shoulder brace at 15° of abduction and neutral rotation protect the patient for the first month post-surgery but physical therapy can immediately start. PMID:23738290

  9. Posterior Tibial Tendon Insufficiency Results at Different Stages

    PubMed Central

    Page, Alexandra; Sung, Il-Hoon; O’Malley, Martin J.; Inda, David; Choung, Steven

    2006-01-01

    The results of surgical treatment of posterior tibial tendon insufficiency (PTTI) may be different at different stages of the disease. No single study has compared the results at different stages. This comparison can be helpful to the patient and physician if the patient asks “What if I wait and the disease progresses, how will my results be different?” A preliminary study comparing results for stage IIa, stage IIb (advanced stage II), and stage III was performed followed by a larger study comparing IIa and IIb with 26 and 22 patients, respectively. American Orthopaedic Foot and Ankle Society (AOFAS) outcome scores as well as radiographs and functional questions were used. Nearly all patients, regardless of stage, felt they were helped by surgical treatment. However, the lowest AOFAS score was in stage III, the most advanced stage investigated in this study. In comparing stage IIa and IIb patients, stage IIb patients had a statistically higher incidence of lateral discomfort. Although statistically significant differences were not found in all comparisons, this study suggests that the results of surgical treatment for PTTI declines with increasing stage or severity of disease. PMID:18751830

  10. Gyrokinetic simulations of the tearing instability

    SciTech Connect

    Numata, Ryusuke; Dorland, William; Howes, Gregory G.; Loureiro, Nuno F.; Tatsuno, Tomoya

    2011-11-15

    Linear gyrokinetic simulations covering the collisional-collisionless transitional regime of the tearing instability are performed. It is shown that the growth rate scaling with collisionality agrees well with that predicted by a two-fluid theory for a low plasma beta case in which ion kinetic dynamics are negligible. Electron wave-particle interactions (Landau damping), finite Larmor radius, and other kinetic effects invalidate the fluid theory in the collisionless regime, in which a general non-polytropic equation of state for pressure (temperature) perturbations should be considered. We also vary the ratio of the background ion to electron temperatures and show that the scalings expected from existing calculations can be recovered, but only in the limit of very low beta.

  11. Observation of Spontaneous Neoclassical Tearing Modes

    SciTech Connect

    E.D. Fredrickson

    2001-10-03

    We present data in this paper from the Tokamak Fusion Test Reactor (TFTR) which challenges the commonly held belief that extrinsic MHD events such as sawteeth or ELMs [edge localized modes] are required to provide the seed islands that trigger Neoclassical Tearing Modes (NTMs). While sawteeth are reported to provide the trigger for most of the NTMs on DIII-D [at General Atomics in San Diego, California] and ASDEX-U [at Max-Planck-Institut fuer Plasmaphysik in Garching, Germany], the majority of NTMs seen in TFTR occur in plasmas without sawteeth, that is which are above the beta threshold for sawtooth stabilization. Examples of NTMs appearing in the absence of any detectable extrinsic MHD activity will be shown. Conversely, large n=1 modes in plasmas above the NTM beta threshold generally do not trigger NTMs. An alternative mechanism for generating seed islands will be discussed.

  12. Viscoplastic tearing of polyethylene thin film

    NASA Astrophysics Data System (ADS)

    Hegyi, Dezso; Pellegrino, Sergio

    2015-05-01

    Recent advances in noncontact strain measurement techniques and large-strain constitutive modeling of the linear low-density polyethylene film used in NASA superpressure balloons StratoFilm 420 are combined to provide a novel measurement technique for the tear propagation critical value of the J-integral. Previously these measurements required complex test configurations and procedures. It is found that the critical value of the J-integral increases by approximately 50 % when the strain rate is decreased from 1.33×10-4 s-1 to 1.33×10-5 s-1. It is shown that there is good correlation between measurements made on uniaxially loaded dogbone samples and circular diaphragms loaded by pressure, both with a 2-mm-wide slit in the middle. This result indicates that more extensive studies of strain-rate dependence may be made with the simpler, uniaxial test configuration.

  13. Treatment of meniscal tears: An evidence based approach

    PubMed Central

    Mordecai, Simon C; Al-Hadithy, Nawfal; Ware, Howard E; Gupte, Chinmay M

    2014-01-01

    Treatment options for meniscal tears fall into three broad categories; non-operative, meniscectomy or meniscal repair. Selecting the most appropriate treatment for a given patient involves both patient factors (e.g., age, co-morbidities and compliance) and tear characteristics (e.g., location of tear/age/reducibility of tear). There is evidence suggesting that degenerative tears in older patients without mechanical symptoms can be effectively treated non-operatively with a structured physical therapy programme as a first line. Even if these patients later require meniscectomy they will still achieve similar functional outcomes than if they had initially been treated surgically. Partial meniscectomy is suitable for symptomatic tears not amenable to repair, and can still preserve meniscal function especially when the peripheral meniscal rim is intact. Meniscal repair shows 80% success at 2 years and is more suitable in younger patients with reducible tears that are peripheral (e.g., nearer the capsular attachment) and horizontal or longitudinal in nature. However, careful patient selection and repair technique is required with good compliance to post-operative rehabilitation, which often consists of bracing and non-weight bearing for 4-6 wk. PMID:25035825

  14. Correlation between rotator cuff tear and glenohumeral degeneration.

    PubMed

    Hsu, Horng-Chaung; Luo, Zong-Ping; Stone, James J; Huang, Tze-Hsi; An, Kai-Nan

    2003-02-01

    We studied the occurrence and correlation between a rotator cuff tear and glenohumeral degeneration. 44 cadaveric shoulders (22 right) were obtained from 32 subjects (18 females), mean age 73 (62-86) years and without a history of systemic diseases. Rotator cuffs were exposed and tear size (14 shoulders) was measured after removal of soft tissue and deltoid. Articular cartilage damage of the glenoid and humeral head was recorded by photography. A grading system of 1 (intact), 2 (mild) and 3 (severe) was used to determine the severity of cartilage damage. The area of articular cartilage damage was calculated using the Sonic Digitizer Analyzing System. The area of articular cartilage damage to the glenoid and the humeral head in the rotator cuff tear group was 32% and 36%, respectively. It was greater than that in the groups without a tear, which was 6% in the glenoid and 7% in the humeral head. However, it was not correlated with the size of the tear. Most of the articular cartilage damage in massive and large rotator cuff tears was located in the anterior-inferior portion of the glenoid and in the posterior portion of the humeral head. The articular cartilage damage area of the glenoid was correlated with that of the humeral head. In conclusion, the area of glenohumeral degeneration was greater in the rotator cuff tear group and was located in a specific site. PMID:12635800

  15. The potential of optical coherence tomography in meniscal tear characterization

    NASA Astrophysics Data System (ADS)

    Ling, Hang-yin; Guo, Shuguang; Thieman, Kelley M.; Wise, Brent T.; Pozzi, Antonio; Xie, Huikai; Horodyski, MaryBeth

    2009-02-01

    Meniscal tear is one of the most common knee injuries leading to pain and discomfort. Partial and total meniscectomies have been widely used to treat the avascular meniscal injuries in which tears do not heal spontaneously. However, the meniscectomies would cause an alteration of the tibiofemoral contact mechanics resulting in progressive osteoarthritis (OA). To mitigate the progression of OA, maximal preservation of meniscal tissue is recommended. The clinical challenge is deciding which meniscal tears are amenable to repair and which part of damaged tissues should be removed. Current diagnosis techniques such as arthroscopy and magnetic resonance imaging can provide macrostructural information of menisci, but the microstructural changes that occur prior to the observable meniscal tears cannot be identified by these techniques. Serving as a nondestructive optical biopsy, optical coherence tomography (OCT), a newly developed imaging modality, can provide high resolution, cross-sectional images of tissues and has been shown its capabilty in arthroscopic evaulation of articular cartilage. Our research was to demonstrate the potential of using OCT for nondestructive characterization of the histopathology of different types of meniscal tears from clinical cases in dogs, providing a fundamental understanding of the failure mechanism of meniscal tears. First, cross-sectional images of torn canine menisci obtained from the OCT and scanning electronic microscopy (SEM) were be compared. By studying the organization of collegan fibrils in torn menisci from the SEM images, the feasibility of using OCT to characterize the organization of collegan fibrils was elucidated. Moreover, the crack size of meniscal tears was quantatitively measured from the OCT images. Changes in the crack size of the tear may be useful for understanding the failure mechanism of meniscal tears.

  16. Immunoglobulin Concentration in Tears of Contact Lens Wearers

    PubMed Central

    Maurya, Rajendra P.; Bhushan, Prashant; Singh, Virendra P.; Singh, Mahendra K.; Kumar, Prakash; Bhatia, Ravindra P.S.; Singh, Usha

    2014-01-01

    Purpose: To evaluate changes in the concentration of tear immunoglobulins in contact lens wearers. Methods: A total of 45 cases including 23 contact lens wearers (43 eyes) and 22 age and sex matched healthy controls having no ocular pathology were studied for immunoglobulins (IgA, IgG, IgM) in their tears by single radial immunodiffusion method. Results: Most of the cases used soft (56.6%) and semi-soft gas permeable (30.4%) contact lenses. Tear IgM was detected in only 17.4% and tear IgG in 43.6% of contact lens wearers, while in controls IgG was detected in 9.1% but none of the controls had IgM. There was a significant rise in total tear IgA (13.17 ± 4.44 mg/dl) in contact lens wearer as compared to controls (8.93 ± 3.79 mg/dl). Rise of tear IgA was more in symptomatic patients (15.38 ± 5.28 mg/dl) and in those wearing hard (19.73 ± 5.43 mg/dl) and semi-soft contact lenses (13.31 ± 5.43 mg/dl). A significant increase in tear IgA was noticed in subjects wearing lenses for >3 years (15.69 ± 5.39 mg/dl). About 43.4% of lens wearers were symptomatic and 80% of their lenses showed deposits and/or haziness. All cases with IgM in tear were symptomatic. Conclusion: The relation of immunoglobulin concentration with increasing duration of wear and material of contact lens shows that tear immunoglobulin rise accrues due to mechanical stimulation, hence contact lenses should not be used for a long period and lenses of hard nature should be discouraged. The maintenance, cleaning and deproteinization of the lenses are of high importance to avoid immunostimulation. PMID:25667732

  17. Protect Your Tendons: Preventing the Pain of Tendinitis

    MedlinePLUS

    ... knee, rotate your shoulder, and grasp with your hand. Tendinitis is inflammation of a tendon. (When you see “itis” at the end of a medical word, it means inflammation.) In tendinitis, the tendon gets inflamed and can rub against bone, making movement painful. Tendinitis is usually ...

  18. Harnessing endogenous stem/progenitor cells for tendon regeneration

    PubMed Central

    Lee, Chang H.; Lee, Francis Y.; Tarafder, Solaiman; Kao, Kristy; Jun, Yena; Yang, Guodong; Mao, Jeremy J.

    2015-01-01

    Current stem cell–based strategies for tissue regeneration involve ex vivo manipulation of these cells to confer features of the desired progenitor population. Recently, the concept that endogenous stem/progenitor cells could be used for regenerating tissues has emerged as a promising approach that potentially overcomes the obstacles related to cell transplantation. Here we applied this strategy for the regeneration of injured tendons in a rat model. First, we identified a rare fraction of tendon cells that was positive for the known tendon stem cell marker CD146 and exhibited clonogenic capacity, as well as multilineage differentiation ability. These tendon-resident CD146+ stem/progenitor cells were selectively enriched by connective tissue growth factor delivery (CTGF delivery) in the early phase of tendon healing, followed by tenogenic differentiation in the later phase. The time-controlled proliferation and differentiation of CD146+ stem/progenitor cells by CTGF delivery successfully led to tendon regeneration with densely aligned collagen fibers, normal level of cellularity, and functional restoration. Using siRNA knockdown to evaluate factors involved in tendon generation, we demonstrated that the FAK/ERK1/2 signaling pathway regulates CTGF-induced proliferation and differentiation of CD146+ stem/progenitor cells. Together, our findings support the use of endogenous stem/progenitor cells as a strategy for tendon regeneration without cell transplantation and suggest this approach warrants exploration in other tissues. PMID:26053662

  19. Muscle power attenuation by tendon during energy dissipation

    PubMed Central

    Konow, Nicolai; Azizi, Emanuel; Roberts, Thomas J.

    2012-01-01

    An important function of skeletal muscle is deceleration via active muscle fascicle lengthening, which dissipates movement energy. The mechanical interplay between muscle contraction and tendon elasticity is critical when muscles produce energy. However, the role of tendon elasticity during muscular energy dissipation remains unknown. We tested the hypothesis that tendon elasticity functions as a mechanical buffer, preventing high (and probably damaging) velocities and powers during active muscle fascicle lengthening. We directly measured lateral gastrocnemius muscle force and length in wild turkeys during controlled landings requiring rapid energy dissipation. Muscle-tendon unit (MTU) strain was measured via video kinematics, independent of muscle fascicle strain (measured via sonomicrometry). We found that rapid MTU lengthening immediately following impact involved little or no muscle fascicle lengthening. Therefore, joint flexion had to be accommodated by tendon stretch. After the early contact period, muscle fascicles lengthened and absorbed energy. This late lengthening occurred after most of the joint flexion, and was thus mainly driven by tendon recoil. Temporary tendon energy storage led to a significant reduction in muscle fascicle lengthening velocity and the rate of energy absorption. We conclude that tendons function as power attenuators that probably protect muscles against damage from rapid and forceful lengthening during energy dissipation. PMID:21957134

  20. 21 CFR 888.3025 - Passive tendon prosthesis.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ...device is implanted for a period of 2 to 6 months to aid growth of a new tendon sheath. The device is not intended as a permanent implant nor to function as a replacement for the ligament or tendon nor to function as a scaffold for soft tissue ingrowth....

  1. Suitability of Thiel embalmed tendons for biomechanical investigation.

    PubMed

    Fessel, Gion; Frey, Kevin; Schweizer, Andreas; Calcagni, Maurizio; Ullrich, Oliver; Snedeker, Jess G

    2011-05-01

    The standard post-mortem storage method for biomechanical testing is freezing. Freezing minimally alters the biomechanical characteristics of tendons but only suspends the process of decay. Chemical fixation arrests decay and overcomes risk of infection, but alters the biomechanical properties of tendons. On the other hand, Thiel preservation has been reported to maintain soft tissue consistency similar to that of living tissue. The current study investigates the effects of Thiel embalming on human digitorum profundus tendons (FDP) from fresh-frozen and Thiel embalmed cadavers. Cross-sectional area was measured at pre-load, samples were preconditioned and then ramped at a constant strain-rate to failure. Thiel preserved tendons had statistically lower failure stress with median of 38MPa compared to fresh frozen samples with median of 60MPa (p-value=0.048) and trended to a decreased tangential modulus. To overcome limited donor number and masking factors of age, gender, and time embalmed, we also performed experiments in rat tail tendon fascicle. Similar quasi-static ramp to failure tests were performed with control and Thiel treated sample pairs. Similar differences were observed to those found as in human FDP, however these trends were statistically significant. In both tendons, Thiel preserved samples demonstrated altered failure characteristics, indicating a different collagen fiber/collagen network failure mechanism most likely due to partial denaturing by boric acid in Thiel solution. In conclusion, Thiel embalmed tendons did not faithfully represent the biomechanical characteristics of fresh frozen tendons. PMID:21511447

  2. MAC-EYE: a Tendon Driven Fully Embedded Robot Eye

    E-print Network

    Cannata, Giorgio

    the possibility of designing a robot eye with kinematics and actuation similar to those of the human eyeMAC-EYE: a Tendon Driven Fully Embedded Robot Eye Dario Biamino, Giorgio Cannata, Marco Maggiali. In particular, we tried to exploit the spherical shape of the eye and to study the feasibility of a tendon based

  3. A rare knee extensor mechanism injury: Vastus intermedius tendon rupture

    PubMed Central

    Cetinkaya, Engin; Aydin, Canan Gonen; Akman, Yunus Emre; Gul, Murat; Arikan, Yavuz; Aycan, Osman Emre; Kabukcuoglu, Yavuz Selim

    2015-01-01

    Introduction Quadriceps tendon injuries are rare. There is a limited number of studies in the literature, reporting partial quadriceps tendon ruptures. We did not find any study reporting an isolated vastus intermedius tendon injury in the literature. Presentation of case A 22 years old professional rugby player with the complaints of pain in the right lower limb, decreased range of motion in right knee and a mass in the mid-anterior of the right thigh applied following an overloading on his hyperflexed knee during a rugby match. T2 sequence magnetic resonance images revealed discontinuity in the vastus intermedius tendon and intramuscular hematoma. The patient has been conservatively treated. Discussion Quadriceps tendon ruptures generally occur after the 4th decade in the presence of degenerative changes. Our case is a young professional rugby player. Isolated vastus intermedius tendon rupture is unusual. Conservative treatment is performed as the intermedius tendon is in the deepest layer of the quadriceps muscle. Conclusion We report the first case of isolated rupture of the vastus intermedius tendon in the literature and we claim that disorder may be succesfully treated with conservative treatment and adequate physiotheraphy. PMID:26298093

  4. AN IN VIVO METHOD TO QUANTIFY BIOMECHANCAL COMPROMISE IN TENDON

    E-print Network

    Sethares, William A.

    . Comparative local stiffnesses (normal versus tendinopathic) indicate the degree of mechanical compromiseAN IN VIVO METHOD TO QUANTIFY BIOMECHANCAL COMPROMISE IN TENDON R. Vanderby1 , S.E. Kuehl2 , M compromise and monitor functional healing in pathological tendons. 2. INTRODUCTION Hughes and Kelly's [1

  5. Ultrasound Diagnosis of Bilateral Quadriceps Tendon Rupture After Statin Use

    PubMed Central

    Nesselroade, Ryan D.; Nickels, Leslie Connor

    2010-01-01

    Simultaneous bilateral quadriceps tendon rupture is a rare injury. We report the case of bilateral quadriceps tendon rupture sustained with minimal force while refereeing a football game. The injury was suspected to be associated with statin use as the patient had no other identifiable risk factors. The diagnosis was confirmed using bedside ultrasound. PMID:21079697

  6. Relationship between tendon stiffness and failure: a metaanalysis.

    PubMed

    LaCroix, Andrew S; Duenwald-Kuehl, Sarah E; Lakes, Roderic S; Vanderby, Ray

    2013-07-01

    Tendon is a highly specialized, hierarchical tissue designed to transfer forces from muscle to bone; complex viscoelastic and anisotropic behaviors have been extensively characterized for specific subsets of tendons. Reported mechanical data consistently show a pseudoelastic, stress-vs.-strain behavior with a linear slope after an initial toe region. Many studies report a linear, elastic modulus, or Young's modulus (hereafter called elastic modulus) and ultimate stress for their tendon specimens. Individually, these studies are unable to provide a broader, interstudy understanding of tendon mechanical behavior. Herein we present a metaanalysis of pooled mechanical data from a representative sample of tendons from different species. These data include healthy tendons and those altered by injury and healing, genetic modification, allograft preparation, mechanical environment, and age. Fifty studies were selected and analyzed. Despite a wide range of mechanical properties between and within species, elastic modulus and ultimate stress are highly correlated (R(2) = 0.785), suggesting that tendon failure is highly strain-dependent. Furthermore, this relationship was observed to be predictable over controlled ranges of elastic moduli, as would be typical of any individual species. With the knowledge gained through this metaanalysis, noninvasive tools could measure elastic modulus in vivo and reasonably predict ultimate stress (or structural compromise) for diseased or injured tendon. PMID:23599401

  7. Explosive tearing mode reconnection in the magnetospheric tail

    NASA Technical Reports Server (NTRS)

    Galeev, A. A.; Coroniti, F. V.; Ashour-Abdalla, M.

    1978-01-01

    A speculative model for the nonlinear phase of the collisionless tearing instability is developed for the case of a single long wavelength tearing mode. Using an energy principle formalism, we find that the nonlinear growth rate is linearly proportional to the mode amplitude. Hence in the nonlinear phase, the tearing mode grows explosively in time, and saturates when the width of the magnetic islands become comparable to the thickness of the current sheet. For typical plasma sheet parameters, the explosive phase lasts 5-10 minutes, and develops cross-tail emf's of several 100 KV.

  8. Non-linear evolution of double tearing modes in tokamaks

    SciTech Connect

    Fredrickson, E.; Bell, M.; Budny, R.V.; Synakowski, E.

    1999-12-17

    The delta prime formalism with neoclassical modifications has proven to be a useful tool in the study of tearing modes in high beta, collisionless plasmas. In this paper the formalism developed for the inclusion of neoclassical effects on tearing modes in monotonic q-profile plasmas is extended to plasmas with hollow current profiles and double rational surfaces. First, the classical formalism of tearing modes in the Rutherford regime in low beta plasmas is extended to q profiles with two rational surfaces. Then it is shown that this formalism is readily extended to include neoclassical effects.

  9. Double lateral shearing interferometer for the quantitative measurement of tear film topography

    E-print Network

    Dainty, Chris

    Double lateral shearing interferometer for the quantitative measurement of tear film topography topography features: postblink tear undulation, tear breakup, eyelid-produced bumps and ridges, bubbles. A more suitable technique to study the tear topography was proposed by Licznerski et al.,31 where

  10. SIMULATION OF POROSITY AND HOT TEARS IN A SQUEEZE CAST MAGNESIUM CONTROL ARM

    E-print Network

    Beckermann, Christoph

    SIMULATION OF POROSITY AND HOT TEARS IN A SQUEEZE CAST MAGNESIUM CONTROL ARM K.D. Carlson1 , C: Magnesium Alloys, Casting, Shrinkage Porosity, Hot Tears, Modeling Abstract Simulations are performed and hot tears in squeeze casting of magnesium alloys. Introduction Both shrinkage porosity and hot tears

  11. Force Model for Control of Tendon Driven Hands

    NASA Technical Reports Server (NTRS)

    Pena, Edward; Thompson, David E.

    1997-01-01

    Knowing the tendon forces generated for a given task such as grasping via a model, an artificial hand can be controlled. A two-dimensional force model for the index finger was developed. This system is assumed to be in static equilibrium, therefore, the equations of equilibrium were applied at each joint. Constraint equations describing the tendon branch connectivity were used. Gaussian elimination was used to solve for the unknowns of the Linear system. Results from initial work on estimating tendon forces in post-operative hands during active motion therapy were discussed. The results are important for understanding the effects of hand position on tendon tension, elastic effects on tendon tension, and overall functional anatomy of the hand.

  12. Neglected bilateral rupture of the patellar tendon: A case report.

    PubMed

    Cherrad, Taoufik; Louaste, Jamal; Kasmaoui, El Houcine; Bousbaä, Hicham; Rachid, Khaled

    2015-12-01

    Simultaneous bilateral rupture of the patellar tendon (PT) is extremely rare and is generally associated to some chronic diseases. When the rupture becomes chronic, it is more difficult to repair that as it remained untreated. The diagnosis, which is clinical, is often delayed, guided by standard radiography and confirmed by ultrasound or MRI. The management of a bilateral neglected, chronic patellar tendon rupture must address some serious difficulties: the proximally retracted patella, the reconstruction of the patellar tendon, finally, the temporary protection of this repair. We report a case of neglected bilateral rupture of the patellar tendon in a chronic hemodialysis patient, treated with a plastic surgery of the ipsilateral quadriceps tendon. PMID:26566349

  13. System and Method for Tensioning a Robotically Actuated Tendon

    NASA Technical Reports Server (NTRS)

    Reiland, Matthew J. (Inventor); Diftler, Myron A. (Inventor)

    2013-01-01

    A tendon tensioning system includes a tendon having a proximal end and a distal end, an actuator, and a motor controller. The actuator may include a drive screw and a motor, and may be coupled with the proximal end of the tendon and configured to apply a tension through the tendon in response to an electrical current. The motor controller may be electrically coupled with the actuator, and configured to provide an electrical current having a first amplitude to the actuator until a stall tension is achieved through the tendon; provide a pulse current to the actuator following the achievement of the stall tension, where the amplitude of the pulse current is greater than the first amplitude, and return the motor to a steady state holding current following the conclusion of the pulse current.

  14. Torque Control of Underactuated Tendon-driven Robotic Fingers

    NASA Technical Reports Server (NTRS)

    Abdallah, Muhammad E. (Inventor); Ihrke, Chris A. (Inventor); Reiland, Matthew J. (Inventor); Wampler, Charles W. (Inventor); Diftler, Myron A. (Inventor); Platt, Robert (Inventor); Bridgwater, Lyndon (Inventor)

    2013-01-01

    A robotic system includes a robot having a total number of degrees of freedom (DOF) equal to at least n, an underactuated tendon-driven finger driven by n tendons and n DOF, the finger having at least two joints, being characterized by an asymmetrical joint radius in one embodiment. A controller is in communication with the robot, and controls actuation of the tendon-driven finger using force control. Operating the finger with force control on the tendons, rather than position control, eliminates the unconstrained slack-space that would have otherwise existed. The controller may utilize the asymmetrical joint radii to independently command joint torques. A method of controlling the finger includes commanding either independent or parameterized joint torques to the controller to actuate the fingers via force control on the tendons.

  15. Achilles Tendon Open Repair Augmented with Volar Turndown Tendon Flap and Deep Posterior Crural Fasciotomy

    PubMed Central

    Özer, Hamza; Selek, Hakan; Harput, Gülcan; Öznur, Ali; Baltac?, Gül

    2014-01-01

    Objectives: The aim of the study was to investigate the outcomes after open repair of Achilles tendon rupture with augmented volar turndown gastrocnemius flap and deep posterior crural fasciotomy. Methods: Twenty-three (22male/1female) patients with acute Achilles tendon injury were operated. Open end to end repair and augmentation with a volar turndown gastrocnemius flap and fasciotomy of the deep posterior compartment was performed in each patient. Home physiotherapy program was instructed for each patient. Muscle strength, balance and jump performance were assessed. Results: All patients returned to their preinjury activity level and repairs healed without any major complication. One patient had serous drainage who did not require surgical intervention (4,3%). There was no significant difference between involved and uninvolved leg in terms of concentric and eccentric muscle strength (p=0.82 and p=0.53, respectively). In Y balance test, there was no significant difference between involved and uninvolved legs in anterior (p=0.06), posteromedial (p=0.97) and posterolateral (p=1.00). In addition, there were no significant differences between leg in vertical jump (p=0.16) and one leg hop (p=0.15) tests. AOFAS Hindfoot score was 98.6±2.3 (93-100). Conclusion: Open end to end repair of the Achilles tendon rupture with augmentation and fasciotomy of the deep posterior compartment healed without any major complication. Fasciotomy of the deep posterior compartment decreased the tension at the skin repair site while decompressing the supeficial compartment anteriorly. Additionally, the augmented bulky repair construct of the Achilles tendon cambered volarly through the deep posterior compartment and decreased irritation sense during and after tendon healing.

  16. Pectoralis major tendon rupture. Surgical procedures review.

    PubMed Central

    Merolla, Giovanni; Paladini, Paolo; Campi, Fabrizio; Porcellini, Giuseppe

    2012-01-01

    Summary Pectoralis major (PM) muscle is the powerful dynamic stabiliser of the shoulder that acts as a flexor, adductor and internal rotator. The rupture of the PM tendon is a relatively rare injury that was firstly described in a French boy by Patissier in 1822 and later, in 1861, by Letenneur who reported another similiar case. To date, over 200 cases have been published. In this article we describe the clinical anatomy and the mechanism of injuries of PM and we review the surgical procedures for acute and chronic ruptures. PMID:23738281

  17. Mechanical model of a single tendon finger

    NASA Astrophysics Data System (ADS)

    Rossi, Cesare; Savino, Sergio

    2013-10-01

    The mechanical model of a single tendon three phalanxes finger is presented. By means of the model both kinematic and dynamical behavior of the finger itself can be studied. This finger is a part of a more complex mechanical system that consists in a four finger grasping device for robots or in a five finger human hand prosthesis. A first prototype has been realized in our department in order to verify the real behavior of the model. Some results of both kinematic and dynamical behavior are presented.

  18. Injecting Joints and Tendons With Steroids

    PubMed Central

    Gershon, Sydney L.

    1983-01-01

    The local intra-articular injection of cortisone compounds is a dependable method for giving patients relief from the pain and swelling of arthritic joints. Injecting the diseased synovium surrounding a joint or tendon sheath or lining a bursa is usually an easy procedure, and the first injection has few contraindications if it is done cautiously. Many clinicians therefore readily embark upon treating patients with steroid injections. However, problems, including post-injection flares, infections and hematomata may begin about 12 hours after an injection. Indications and contraindications for administering injections are therefore discussed, and limitations and precautionary measures are explained. PMID:21283480

  19. The anisotropic compressive mechanical properties of the rabbit patellar tendon.

    PubMed

    Williams, Lakiesha N; Elder, Steven H; Bouvard, J L; Horstemeyer, M F

    2008-01-01

    In this study, we examine the transverse and longitudinal compressive mechanical behavior of the rabbit patellar tendon. The anisotropic compressive properties are of interest, because compression occurs where the tendon attaches to bone and where the tendon wraps around bone leading to the development of fibro-cartilaginous matrices. We quantified the time dependent viscoelastic and anisotropic behavior of the tendon under compression. For both orientations, sections of patellar tendon were drawn from mature male white New Zealand rabbits in preparation for testing. The tendons were sequentially compressed to 40% strain at strain rates of 0.1, 1 and 10% strain(s) using a computer-controlled stepper motor driven device under physiological conditions. Following monotonic loading, the tendons were subjected to stress relaxation. The tendon equilibrium compressive modulus was quantified to be 19.49+/-11.46 kPa for the transverse direction and 1.11+/-0.57 kPa for the longitudinal direction. The compressive modulus at applied strain rates of 0.1, 1 and 10% strain(s) in the transverse orientation were 13.48+/-2.31, 18.24+/-4.58 and 20.90+/-8.60 kPa, respectively. The compressive modulus at applied strain rates of 0.1, 1 and 10% strain/s in the longitudinal orientation were 0.19+/-0.11, 1.27+/-1.38 and 3.26+/-3.49 kPa, respectively. The modulus values were almost significantly different for the examination of the effect of orientation on the equilibrium modulus (p=0.054). Monotonic loading of the tendon showed visual differences of the strain rate dependency; however, no significant difference was shown in the statistical analysis of the effect of strain rate on compressive modulus. The statistical analysis of the effect of orientation on compressive modulus showed a significant difference. The difference shown in the orientation analysis validated the anisotropic nature of the tendon. PMID:19065006

  20. Scx-transduced tendon-derived stem cells (tdscs) promoted better tendon repair compared to mock-transduced cells in a rat patellar tendon window injury model.

    PubMed

    Tan, Chunlai; Lui, Pauline Po Yee; Lee, Yuk Wa; Wong, Yin Mei

    2014-01-01

    We hypothesized that the transplantation of Scx-transduced tendon-derived stem cells (TDSCs) promoted better tendon repair compared to the transplantation of mock-transduced cells. This study thus aimed to investigate the effect of Scx transduction on the expression of lineage markers in TDSCs and the effect of the resulting cell line in the promotion of tendon repair. Rat non-GFP or GFP-TDSCs were transduced with Scx or empty lentiviral vector (Mock) and selected by blasticidin. The mRNA expressions of Scx and different lineage markers were examined by qRT-PCR. The effect of the transplantation of GFP-TDSC-Scx on tendon repair was then tested in a rat unilateral patellar tendon window injury model. The transplantation of GFP-TDSC-Mock and scaffold-only served as controls. At week 2, 4 and 8 post-transplantation, the repaired patellar tendon was harvested for ex vivo fluorescent imaging, vivaCT imaging, histology, immunohistochemistry and biomechanical test. GFP-TDSC-Scx consistently showed higher expressions of most of tendon- and cartilage- related markers compared to the GFP-TDSC-Mock. However, the effect of Scx transduction on the expressions of bone-related markers was inconclusive. The transplanted GFP-TDSCs could be detected in the window wound at week 2 but not at week 4. Ectopic mineralization was detected in some samples at week 8 but there was no difference among different groups. The GFP-TDSC-Scx group only statistically significantly improved tendon repair histologically and biomechanically compared to the Scaffold-only group and the GFP-TDSC-Mock group at the early stage of tendon repair. There was significant higher expression of collagen type I in the window wound in the GFP-TDSC-Scx group compared to the other two groups at week 2. The transplantation of GFP-TDSC-Scx promoted healing at the early stage of tendon repair in a rat patellar tendon window injury model. PMID:24831949

  1. Collisionless tearing instability of a bi-Maxwellian neutral sheet - An integrodifferential treatment with exact particle orbits

    NASA Technical Reports Server (NTRS)

    Burkhart, G. R.; Chen, J.

    1989-01-01

    The integrodifferential equation describing the linear tearing instability in the bi-Maxwellian neutral sheet is solved without approximating the particle orbits or the eigenfunction psi. Results of this calculation are presented. Comparison between the exact solution and the three-region approximation motivates the piecewise-straight-line approximation, a simplification that allows faster solution of the integrodifferential equation, yet retains the important features of the exact solution.

  2. Human patellar tendon stiffness is restored following graft harvest for anterior cruciate ligament surgery.

    PubMed

    Reeves, Neil D; Maganaris, Constantinos N; Maffulli, Nicola; Rittweger, Joern

    2009-05-11

    Minimising post-operative donor site morbidity is an important consideration when selecting a graft for surgical reconstruction of the torn anterior cruciate ligament (ACL). One of the most common procedures, the bone-patellar tendon-bone (BPTB) graft involves removal of the central third from the tendon. However, it is unknown whether the mechanical properties of the donor site (patellar tendon) recover. The present study investigated the mechanical properties of the human patellar tendon in 12 males (mean+/-S.D. age: 37+/-14 years) who had undergone surgical reconstruction of the ACL using a BPTB graft between 1 and 10 years before the study (operated knee; OP). The uninjured contralateral knee served as a control (CTRL). Patellar tendon mechanical properties were assessed in vivo combining dynamometry with ultrasound imaging. Patellar tendon stiffness was calculated from the gradient of the tendon's force-elongation curve. Tendon stiffness was normalised to the tendon's dimensions to obtain the tendon's Young's modulus. Cross-sectional area (CSA) of OP patellar tendons was larger by 21% than CTRL tendons (P<0.01). Patellar tendon stiffness was not significantly different between OP and CTRL tendons, but the Young's modulus was lower by 24% in OP tendons (P<0.01). A compensatory enlargement of the patellar tendon CSA, presumably due to scar tissue formation, enabled a recovery of tendon stiffness in the OP tendons. The newly formed tendon tissue had inferior properties as indicated by the reduced tendon Young's modulus, but it increased to a level that enabled recovery of tendon stiffness. PMID:19268289

  3. Tears of wine: new insights on an old phenomenon

    PubMed Central

    Venerus, David C.; Nieto Simavilla, David

    2015-01-01

    Anyone who has enjoyed a glass of wine has undoubtedly noticed the regular pattern of liquid beads that fall along the inside of the glass, or ‘tears of wine.’ The phenomenon is the result of a flow against gravity along the liquid film on the glass, which is induced by an interfacial tension gradient. It is generally accepted that the interfacial tension gradient is due to a composition gradient resulting from the evaporation of ethanol. We re-examine the tears of wine phenomenon and investigate the importance of thermal effects, which previously have been ignored. Using a novel experiment and simple model we find that evaporative cooling contributes significantly to the flow responsible for wine tears, and that this phenomenon occurs primarily because of the thermodynamic behavior of ethanol-water mixtures. Also, the regular pattern of tear formation is identified as a well-known hydrodynamic instability. PMID:26548566

  4. Tear fluid electrolytes and albumin in persons under environmental stress

    SciTech Connect

    Thygesen, J.E.; Bach, B.; Molhave, L.; Pedersen, O.F.; Prause, J.U.; Skov, P.

    1987-06-01

    Sixty-two subjects selected among 287 persons with indoor air complaints were exposed to a standard mixture of 22 different organic gases and vapors normally found in Danish houses. Persons were randomly assigned to one of four exposure groups, and each subject stayed during the test day from 10:00 AM to 4:00 PM under standardized conditions in a climate chamber. During exposure the blink frequency was recorded, and after exposure the tear fluid contents of serum albumin, potassium, and sodium were measured. It was found that the persons had an increased concentration of serum albumin in the tear fluid, and that exposure to high concentrations of organic gases and vapors induced a tear reflex-mediated dilution of the tears.

  5. GTC Simulation of Tearing Modes in Fusion Plasmas

    NASA Astrophysics Data System (ADS)

    Liu, Dongjian; Holod, Ihor; Zhang, Wenlu; Lin, Zhihong

    2014-10-01

    In Tokamak discharge, Tearing modes are very important modes which may cause the disruption and sawtooth crash. For the reason, an effective physics model and corresponding simulation code are needed to study these modes. We have modified the fluid-kinetic hybrid electron model used in Gyro-kinetic Toroidal Code (GTC) and developed both resistive and finite mass electron fluid model for tearing mode simulations. Using the model in GTC, we have successfully recovered linear behavior of both the classical resistive tearing mode and the collisonless tearing mode, and verified the capability of GTC to study this mode. The modified GTC may supply a more powerful implement for kinetic-MHD study of Tokamak plasma.

  6. Tears of wine: new insights on an old phenomenon

    NASA Astrophysics Data System (ADS)

    Venerus, David C.; Nieto Simavilla, David

    2015-11-01

    Anyone who has enjoyed a glass of wine has undoubtedly noticed the regular pattern of liquid beads that fall along the inside of the glass, or ‘tears of wine.’ The phenomenon is the result of a flow against gravity along the liquid film on the glass, which is induced by an interfacial tension gradient. It is generally accepted that the interfacial tension gradient is due to a composition gradient resulting from the evaporation of ethanol. We re-examine the tears of wine phenomenon and investigate the importance of thermal effects, which previously have been ignored. Using a novel experiment and simple model we find that evaporative cooling contributes significantly to the flow responsible for wine tears, and that this phenomenon occurs primarily because of the thermodynamic behavior of ethanol-water mixtures. Also, the regular pattern of tear formation is identified as a well-known hydrodynamic instability.

  7. Tears of wine: new insights on an old phenomenon.

    PubMed

    Venerus, David C; Nieto Simavilla, David

    2015-01-01

    Anyone who has enjoyed a glass of wine has undoubtedly noticed the regular pattern of liquid beads that fall along the inside of the glass, or 'tears of wine.' The phenomenon is the result of a flow against gravity along the liquid film on the glass, which is induced by an interfacial tension gradient. It is generally accepted that the interfacial tension gradient is due to a composition gradient resulting from the evaporation of ethanol. We re-examine the tears of wine phenomenon and investigate the importance of thermal effects, which previously have been ignored. Using a novel experiment and simple model we find that evaporative cooling contributes significantly to the flow responsible for wine tears, and that this phenomenon occurs primarily because of the thermodynamic behavior of ethanol-water mixtures. Also, the regular pattern of tear formation is identified as a well-known hydrodynamic instability. PMID:26548566

  8. The geological signature of a slab tear below the Aegean

    NASA Astrophysics Data System (ADS)

    Jolivet, Laurent; Menant, Armel; Sternai, Pietro; Rabillard, Aurélien; Arbaret, Laurent; Augier, Romain; Laurent, Valentin; Beaudoin, Alexandre; Grasemann, Bernhard; Huet, Benjamin; Labrousse, Loïc; Le Pourhiet, Laetitia

    2015-09-01

    In this paper we explore the geology of the Aegean region in the Miocene to identify the geological signature of a first-order slab tear observed in all tomographic models. From 15 to 8 Ma, the tear is associated, spatially and timely, with a fast clockwise rotation of the External Hellenides, alkaline volcanism, high-temperature metamorphic domes with a predominance of north-dipping detachments, and south-westward migration of granitoid intrusions. These features suggest a warmer geodynamic environment during the rotation and the impact of a hot mantle flow associated with the tear. The ~ 8 Ma duration between the first high-temperature metamorphic domes in the centre of the archipelago and the beginning of the fast rotation may correspond to the time needed for the slab to bend, stretch and finally tear.

  9. Influence of neglecting the curved path of the Achilles tendon on Achilles tendon length change at various ranges of motion

    PubMed Central

    Fukutani, Atsuki; Hashizume, Satoru; Kusumoto, Kazuki; Kurihara, Toshiyuki

    2014-01-01

    Abstract Achilles tendon length has been measured using a straight?line model. However, this model is associated with a greater measurement error compared with a curved?line model. Therefore, we examined the influence of neglecting the curved path of the Achilles tendon on its length change at various ranges of motion. Ten male subjects participated in this study. First, the location of the Achilles tendon was confirmed by using ultrasonography, and markers were attached on the skin over the Achilles tendon path. Then, the three?dimensional coordinates of each marker at dorsiflexion (DF) 15°, plantarflexion (PF) 0°, PF15°, and PF30° were obtained. Achilles tendon length in the curved?line model was calculated as the sum of the distances among each marker. On the other hand, Achilles tendon length in the straight?line model was calculated as the straight distance between the two most proximal and distal markers projected onto the sagittal plane. The difference of the Achilles tendon length change between curved?line and straight?line models was calculated by subtracting the Achilles tendon length change obtained in curved?line model from that obtained in straight?line model with three different ranges of motion (i.e., PF0°, PF15°, and PF30° from DF15°, respectively). As a result, the difference in Achilles tendon length change between the two models increased significantly as the range of motion increased. In conclusion, neglecting the curved path of the Achilles tendon induces substantial overestimation of its length change when the extent of ankle joint angle change is large. PMID:25303951

  10. Cytokine changes in tears and relationship to contact lens discomfort

    PubMed Central

    Zhao, Zhenjun; Naduvilath, Thomas; Lazon de la Jara, Percy

    2015-01-01

    Purpose To determine the reproducibility of a multiplex bead assay for measuring cytokines in tears and correlations between ocular discomfort with or without contact lens wear and the concentration of cytokines in tears. Methods Ninety participants (divided into two groups) were enrolled in this prospective study. They were asked to rate their ocular comfort and collect their tears in the morning and just before sleep for 10 days with or without contact lenses. The participants collected their tears using a glass microcapillary tube for both stages. Galyfilcon A lenses were worn on a daily disposable basis during the contact lens stage, and comfort scores and tears were collected before lens insertion and prior to lens removal at the end of the day. Tears were analyzed for cytokine concentrations using a 27-plex multibead assay. Correlations were sought between cytokine concentrations and comfort. Results There was a significant (p<0.022) decrease in ocular comfort over the day with or without lens wear. The magnitude of ocular discomfort was significantly greater (p<0.009) with lens wear. The concentrations of 12 cytokines differed significantly between the groups; thus, these cytokines were not analyzed further. For the remaining 15 cytokines, interleukin-8 (IL-8) was the only cytokine that changed in both groups during the day without (reduced by >-0.5 Log pg/ml, p<0.001) or with lens wear (reduced by >-0.2 Log pg/ml, p<0.001). The change in the vascular endothelial growth factor (VEGF) concentration only in tears was correlated to ocular comfort, but this was not changed by contact lens wear. Conclusions Ocular comfort during the day is magnified by contact lens wear. However, the increase in the change in comfort during lens wear was not associated with changes in 15 cytokines in the tear film. PMID:25814827

  11. Computations of the current profile influence on tearing instability

    NASA Technical Reports Server (NTRS)

    Blekher, P. M.; Zuyeva, N. M.; Yurchenko, Z. I.

    1983-01-01

    Results of computations of tearing instability of a plasma column in a strong longitudinal magnetic field are presented for different current profiles. The power current profiles j=j sub 0(1-(r/a)(P))(nu) are considered and analyzed for various values of the parameters p and v. The tearing instability of the smoothed two-step profiles is studied. Optimal smoothed two-step profiles are constructed which are stable with respect to all helical largescale perturbations.

  12. [Functional tendon repair in orthopedic tumor surgery].

    PubMed

    Dominkus, M; Sabeti, M; Kotz, R

    2005-06-01

    Large defects of functional soft tissue structures, e.g., extensor mechanism, ligaments, muscles, and joint capsule, may occur in tumor surgery or revision surgery following conventional joint replacement. Reconstruction can be performed using biological grafts such as free or pedicled tendon-muscle flaps, allografts, or synthetic material. Prerequisites for synthetic material are good biologic tolerance with fibroblastic ingrowth, mechanical resistance to fatigue, and a maximum of tension force with a minimum of elongation. In this study we used a nonresorbable band of longitudinal polyester fibers with a minimal rupture level of 4000 N and an elongation rate less than 7% of its original length. The shape of the band was designed for universal use with 40 cm length and 6 cm width. Its primary indication was augmentation or complete reconstruction of the extensor mechanism of the knee joint after large extra-articular tumor resections in primary bone tumors. Furthermore, its use for hip joint capsule reconstruction in luxation, coverage of megaprostheses of the humerus, and augmentation after biological reconstruction of tendons achieved excellent results. PMID:15883785

  13. Current Concepts in Examination and Treatment of Elbow Tendon Injury

    PubMed Central

    Ellenbecker, Todd S.; Nirschl, Robert; Renstrom, Per

    2013-01-01

    Context: Injuries to the tendons of the elbow occur frequently in the overhead athlete, creating a significant loss of function and dilemma to sports medicine professionals. A detailed review of the anatomy, etiology, and pathophysiology of tendon injury coupled with comprehensive evaluation and treatment information is needed for clinicians to optimally design treatment programs for rehabilitation and prevention. Evidence Acquisitions: The PubMed database was searched in January 2012 for English-language articles pertaining to elbow tendon injury. Results: Detailed information on tendon pathophysiology was found along with incidence of elbow injury in overhead athletes. Several evidence-based reviews were identified, providing a thorough review of the recommended rehabilitation for elbow tendon injury. Conclusions: Humeral epicondylitis is an extra-articular tendon injury that is common in athletes subjected to repetitive upper extremity loading. Research is limited on the identification of treatment modalities that can reduce pain and restore function to the elbow. Eccentric exercise has been studied in several investigations and, when coupled with a complete upper extremity strengthening program, can produce positive results in patients with elbow tendon injury. Further research is needed in high-level study to delineate optimal treatment methods. PMID:24427389

  14. Production of a sterilised decellularised tendon allograft for clinical use.

    PubMed

    Huang, Q; Ingham, E; Rooney, P; Kearney, J N

    2013-12-01

    Application of a high-level decontamination or sterilisation procedure and cell removal technique to tendon allograft can reduce the concerns of disease transmission, immune reaction, and may improve remodelling of the graft after implantation. The decellularised matrix can also be used as a matrix for tendon tissue engineering. One such sterilisation factor, Peracetic acid (PAA) has the advantage of not producing harmful reaction residues. The aim of this study was to evaluate the effects of PAA treatment and a cell removal procedure on the production of tendon matrix. Human patellar tendons, thawed from frozen were treated respectively as: Group 1, control with no treatment; Group 2, sterilised with PAA (0.1 % (w/v) PAA for 3 h) Group 3, decellularised (incubation successively in hypotonic buffer, 0.1 % (w/v) sodium dodecyl sulphate, and a nuclease solution); Group 4, decellularised and PAA sterilised. Histological analysis showed that no cells were visible after the decellularisation treatment. The integrity of tendon structure was maintained after decellularisation and PAA sterilisation, however, the collagen waveform was slightly loosened. No contact cytotoxicity was found in any of the groups. Determination of de-natured collagen showed no significant increase when compared with the control. This suggested that the decellularisation and sterilisation processing procedures did not compromise the major properties of the tendon. The sterilised, decellularised tendon could be suitable for clinical use. PMID:23443409

  15. Quantification of regional blood flow to canine flexor tendons

    SciTech Connect

    Weidman, K.A.; Simonet, W.T.; Wood, M.B.; Cooney, W.P.; Ilstrup, D.M.

    1984-01-01

    Although the blood supply and the microcirculation of flexor tendons have been studied and defined extensively using qualitative methods, the quantitative assessment of blood flow has been lacking because of the limitations of the available experimental techniques. The authors studied the regional blood supply to the flexor tendons of dogs by the technique of radionuclide-labeled microspheres. Seven adult mongrel dogs were used. Microsphere injection and tissue-counting techniques previously used for other tissues were applied. Samples of proximal, isthmus, and distal portions of the profundus and superficialis flexor tendons were harvested from each digital unit of available limbs from each dog. Mean (+/- SE) flows (ml/100 g dry tissue/min) were proximal profundus 1.78 +/- 0.60 and superficialis 7.10 +/- 1.50. The differences were significant. The study suggests that regional variation in blood flow to canine digital flexor tendons exists, so that a single value for blood flow to these tendons is not relevant. Furthermore, the study supports the concept of dual (vascular and synovial) nutrition to the digital flexor tendons in dogs. These observations may have implications regarding tendon repair techniques.

  16. Flexor tendon repair with barbed suture: an experimental study.

    PubMed

    Sato, Munenori; Matsumura, Hajime; Gondo, Masahide; Shimada, Kazuki; Watanabe, Katsueki

    2014-12-01

    Various suture materials have been used for tendon repair. Barbed suture in particular has been demonstrated to be effective for both wound closure and tendon repair. Ten fresh-frozen flexor digitorum profundus tendons of pig were transected and repaired using the two-strand modified Kirchmayr-Kessler technique. The samples were divided into two groups: 4-0 barbed absorbable polyglyconate sutures and 4-0 monofilament absorbable polyglyconate sutures. We measured tensile strength and distance that the testing system pulled the tendon using a universal testing machine. Tensile strength at which 1 and 2 mm of gapping occurred was measured visually at the repair site. Tendons repaired by barbed sutures showed greater tensile strength than monofilament sutures forming still 2-mm gap. However, statistical significance was obtained only at 1-mm gap formation. We concluded that for tendon repair, barbed sutures were superior material to monofilament sutures because of their greater tensile strength, reducing both the initial tendon load and the risk of dehiscence. PMID:24121796

  17. The Tendon Injury Response Is Influenced by Decorin and Biglycan

    PubMed Central

    Dunkman, Andrew A.; Buckley, Mark R.; Mienaltowski, Michael J.; Adams, Sheila M.; Thomas, Stephen J.; Satchell, Lauren; Kumar, Akash; Pathmanathan, Lydia; Beason, David P.; Iozzo, Renato V.; Birk, David E.; Soslowsky, Louis J.

    2013-01-01

    Defining the constituent regulatory molecules in tendon is critical to understanding the process of tendon repair and instructive to the development of novel treatment modalities. The purpose of this study is to define the structural, expressional, and mechanical changes in the tendon injury response, and elucidate the roles of two class I small leucine-rich proteoglycans (SLRPs). We utilized biglycan-null, decorin-null and wild type mice with an established patellar tendon injury model. Mechanical testing demonstrated functional changes associated with injury and the incomplete recapitulation of mechanical properties after six weeks. In addition, SLRP deficiency influenced the mechanical properties with a marked lack of improvement between three and six weeks in decorin-null tendons. Morphological analyses of the injury response and role of SLRPs demonstrated alterations in cell density and shape as well as collagen alignment and fibril structure resulting from injury. SLRP gene expression was studied using RT-qPCR with alterations in expression associated with the injured tendons. Our results show that in the absence of biglycan initial healing may be impaired while in the absence of decorin later healing is clearly diminished. This suggests that biglycan and decorin may have sequential roles in the tendon response to injury. PMID:24072490

  18. Multiple tendon xanthomas in patient with heterozygous familial hypercholesterolaemia: sonographic and MRI findings

    PubMed Central

    Dagistan, Emine; Canan, Arzu; Kizildag, Betul; Barut, Abdullah Yuksel

    2013-01-01

    Tendon xanthomas are a component of familial hypercholesterolaemia, which is a hereditary disease and characterised by elevated low-density lipo protein cholesterol plasma levels and premature coronary artery disease. Tendon xanthomas are diagnostic for heterozygous familial hypercholesterolaemia (HFH) and they mostly occur in Achilles tendon. Sonography and MRI are superior to clinical assessment and are useful in detecting tendon xanthomas. In this report, we present ultrasonographic and MRI findings of multiple tendon xanthomas in a case of HFH. PMID:24252837

  19. STRESS CORROSION CRACKING IN TEAR DROP SPECIMENS

    SciTech Connect

    Lam, P; Philip Zapp, P; Jonathan Duffey, J; Kerry Dunn, K

    2009-05-01

    Laboratory tests were conducted to investigate the stress corrosion cracking (SCC) of 304L stainless steel used to construct the containment vessels for the storage of plutonium-bearing materials. The tear drop corrosion specimens each with an autogenous weld in the center were placed in contact with moist plutonium oxide and chloride salt mixtures. Cracking was found in two of the specimens in the heat affected zone (HAZ) at the apex area. Finite element analysis was performed to simulate the specimen fabrication for determining the internal stress which caused SCC to occur. It was found that the tensile stress at the crack initiation site was about 30% lower than the highest stress which had been shifted to the shoulders of the specimen due to the specimen fabrication process. This finding appears to indicate that the SCC initiation took place in favor of the possibly weaker weld/base metal interface at a sufficiently high level of background stress. The base material, even subject to a higher tensile stress, was not cracked. The relieving of tensile stress due to SCC initiation and growth in the HAZ and the weld might have foreclosed the potential for cracking at the specimen shoulders where higher stress was found.

  20. Tenocyte contraction induces crimp formation in tendon-like tissue.

    PubMed

    Herchenhan, Andreas; Kalson, Nicholas S; Holmes, David F; Hill, Patrick; Kadler, Karl E; Margetts, Lee

    2012-03-01

    Tendons are composed of longitudinally aligned collagen fibrils arranged in bundles with an undulating pattern, called crimp. The crimp structure is established during embryonic development and plays a vital role in the mechanical behaviour of tendon, acting as a shock-absorber during loading. However, the mechanism of crimp formation is unknown, partly because of the difficulties of studying tendon development in vivo. Here, we used a 3D cell culture system in which embryonic tendon fibroblasts synthesise a tendon-like construct comprised of collagen fibrils arranged in parallel bundles. Investigations using polarised light microscopy, scanning electron microscopy and fluorescence microscopy showed that tendon constructs contained a regular pattern of wavy collagen fibrils. Tensile testing indicated that this superstructure was a form of embryonic crimp producing a characteristic toe region in the stress-strain curves. Furthermore, contraction of tendon fibroblasts was the critical factor in the buckling of collagen fibrils during the formation of the crimp structure. Using these biological data, a finite element model was built that mimics the contraction of the tendon fibroblasts and monitors the response of the Extracellular matrix. The results show that the contraction of the fibroblasts is a sufficient mechanical impulse to build a planar wavy pattern. Furthermore, the value of crimp wavelength was determined by the mechanical properties of the collagen fibrils and inter-fibrillar matrix. Increasing fibril stiffness combined with constant matrix stiffness led to an increase in crimp wavelength. The data suggest a novel mechanism of crimp formation, and the finite element model indicates the minimum requirements to generate a crimp structure in embryonic tendon. PMID:21735243

  1. Connecting muscles to tendons: tendons and musculoskeletal development in flies and vertebrates

    PubMed Central

    Schweitzer, Ronen; Zelzer, Elazar; Volk, Talila

    2010-01-01

    The formation of the musculoskeletal system represents an intricate process of tissue assembly involving heterotypic inductive interactions between tendons, muscles and cartilage. An essential component of all musculoskeletal systems is the anchoring of the force-generating muscles to the solid support of the organism: the skeleton in vertebrates and the exoskeleton in invertebrates. Here, we discuss recent findings that illuminate musculoskeletal assembly in the vertebrate embryo, findings that emphasize the reciprocal interactions between the forming tendons, muscle and cartilage tissues. We also compare these events with those of the corresponding system in the Drosophila embryo, highlighting distinct and common pathways that promote efficient locomotion while preserving the form of the organism. PMID:20699295

  2. Primary flexor tendon surgery: the search for a perfect result.

    PubMed

    Elliot, David; Giesen, Thomas

    2013-05-01

    Repair of the divided flexor tendon to achieve normal, or near normal, function is an unsolved problem, with each result still uncertain. The authors believe the way forward in primary flexor tendon surgery clinically is by use of strengthened but simpler sutures, appropriate venting of the pulley system, and maintaining early rehabilitation. However, there needs also be consideration of patient factors and other aspects. Research needs to continue more widely, in both the laboratory and the clinical environment, to find ways of better modifying adhesions after surgical repair of the tendon. PMID:23660055

  3. Tendon to bone healing and its implications for surgery

    PubMed Central

    Bunker, Daniel Lee John; Ilie, Victor; Ilie, Vladimir; Nicklin, Sean

    2014-01-01

    Summary Entheses are complex structures which act to reduce stress concentrations between tendon and skeleton tissues. Understanding the development and function of the enthesis organ has implications for surgical repair, particularly in regards to healing and the regulation of tendon to bone engraftment. In this paper we review the development and function of entheses as well as the enthesis organ concept. Next we examine the process of tendon to bone healing and how this can be regulated, before addressing implications for surgical repair and post-operative care. PMID:25489553

  4. Compressive properties of cd-HA-gelatin modified intrasynovial tendon allograft in canine model in vivo

    PubMed Central

    Ikeda, Jun; Zhao, Chunfeng; Chen, Qingshan; Thoreson, Andrew R.; An, Kai-Nan; Amadio, Peter C.

    2013-01-01

    Although we sometimes use the intrasynovial tendon allograft as a donor, the gliding ability of allograft prepared by lyophilization is significantly decreased. The gliding ability of the grafted tendon after tendon reconstruction is very important because the high gliding resistance causes more adhesion and leads to poor clinical results. We recently revealed that tendon surface treatment with a carbodiimide derivatized HA (cd-HA)-gelatin mixture for intrasynovial tendon allograft significantly improved its gliding ability. The purpose of this study was to investigate whether this cd-HA-gelatin treatment affects the tendon mechanical property or not. A total of 40 flexor digitorum profundus (FDP) tendons from canines were evaluated for compressive property by using indentation test. Indentation stiffness was measured for normal tendon, rehydrated tendon after lyophilization, rehydrated tendon after lyophilization that was implanted 6 weeks in vivo, and cd-HA treated rehydrated tendon after lyophilization that was implanted 6 weeks in vivo. The results for all groups showed no significant difference in the tendon compressive properties. The findings of these results demonstrate that cd-HA treatment for intrasynovial tendon allograft is an excellent method to improve the tendon gliding ability after lyophilization without changing the compressive property of donor tendon. PMID:21549380

  5. The long head of the biceps tendon is a suitable cell source for tendon tissue regeneration

    PubMed Central

    Pietschmann, Matthias F.; Gülecyüz, Mehmet F.; Ficklscherer, Andreas; Jansson, Volkmar; Müller, Peter E.

    2014-01-01

    Introduction Tendon tissue engineering (TTE) tries to produce tendinous tissue of high quality to replace dysfunctional tissue. One possible application of TTE might be the replacement of ruptured tissue of the rotator cuff. Autologous tenocytes seem to be most suitable as no differentiation in vitro is necessary. Today it is still uncertain if there is a difference between tendon-derived cells (TDC) of different native tissues. Moreover, the search for suitable scaffolds is another important issue in TTE. Material and methods This study compared TDC of the long head of the biceps tendon (LHB), the anterior cruciate ligament (ACL) and the tendon of the musculus semitendinosus (TMS). The TDC were isolated using the cell migration method. Cell morphology was assessed using light microscopy and gene expression was performed using polymerase chain reaction (PCR). Afterwards, cell seeding efficiency and proliferation were tested on a collagen I scaffold using the WST-1 assay. Results were confirmed using H + E staining. Results The TDC of the LHB showed higher expression levels of collagen type I and decorin (p < 0.01) compared to TDC of other origin. Results showed efficient cell seeding and proliferation within the scaffold. Proliferation within the scaffold was not as high as when cells were cultivated without a scaffold. Conclusions The TDC of the LHB seems to be the most suitable cell source. Further research is necessary to find out if the results can be transferred to an in vivo model. The new collagen I scaffold seems to offer an opportunity to combine good biocompatibility and mechanical strength. PMID:25097592

  6. Decorin expression is important for age-related changes in tendon structure and mechanical properties

    PubMed Central

    Dunkman, Andrew A.; Buckley, Mark R.; Mienaltowski, Michael J.; Adams, Sheila M.; Thomas, Stephen J.; Satchell, Lauren; Kumar, Akash; Pathmanathan, Lydia; Beason, David P.; Iozzo, Renato V.; Birk, David E.; Soslowsky, Louis J.

    2013-01-01

    The aging population is at an increased risk of tendon injury and tendinopathy. Elucidating the molecular basis of tendon aging is crucial to understanding the age-related changes in structure and function in this vulnerable tissue. In this study, the structural and functional features of tendon aging are investigated. In addition, the roles of decorin and biglycan in the aging process were analyzed using transgenic mice at both mature and aged time points. Our hypothesis is that the increase in tendon injuries in the aging population is the result of altered structural properties that reduce the biomechanical function of the tendon and consequently increase susceptibility to injury. Decorin and biglycan are important regulators of tendon structure and therefore, we further hypothesized that decreased function in aged tendons is partly the result of altered decorin and biglycan expression. Biomechanical analyses of mature (day 150) and aged (day 570) patellar tendons revealed deteriorating viscoelastic properties with age. Histology and polarized light microscopy demonstrated decreased cellularity, alterations in tenocyte shape, and reduced collagen fiber alignment in the aged tendons. Ultrastructural analysis of fibril diameter distributions indicated an altered distribution in aged tendons with an increase of large diameter fibrils. Aged wild type tendons maintained expression of decorin which was associated with the structural and functional changes seen in aged tendons. Aged patellar tendons exhibited altered and generally inferior properties across multiple assays. However, decorin-null tendons exhibited significantly decreased effects of aging compared to the other genotypes. The amelioration of the functional deficits seen in the absence of decorin in aged tendons was associated with altered tendon fibril structure. Fibril diameter distributions in the decorin-null aged tendons were comparable to those observed in the mature wild type tendon with the absence of the subpopulation containing large diameter fibrils. Collectively, our findings provide evidence for age-dependent alterations in tendon architecture and functional activity, and further show that lack of stromal decorin attenuates these changes. PMID:23178232

  7. Tension Stiffened and Tendon Actuated Manipulator

    NASA Technical Reports Server (NTRS)

    Doggett, William R. (Inventor); Dorsey, John T. (Inventor); Ganoe, George G. (Inventor); King, Bruce D. (Inventor); Jones, Thomas C. (Inventor); Mercer, Charles D. (Inventor); Corbin, Cole K. (Inventor)

    2015-01-01

    A tension stiffened and tendon actuated manipulator is provided performing robotic-like movements when acquiring a payload. The manipulator design can be adapted for use in-space, lunar or other planetary installations as it is readily configurable for acquiring and precisely manipulating a payload in both a zero-g environment and in an environment with a gravity field. The manipulator includes a plurality of link arms, a hinge connecting adjacent link arms together to allow the adjacent link arms to rotate relative to each other and a cable actuation and tensioning system provided between adjacent link arms. The cable actuation and tensioning system includes a spreader arm and a plurality of driven and non-driven elements attached to the link arms and the spreader arm. At least one cable is routed around the driven and non-driven elements for actuating the hinge.

  8. Cushing, acromegaly, GH deficiency and tendons

    PubMed Central

    Galdiero, Mariano; Auriemma, Renata S.; Pivonello, Rosario; Colao, Annamaria

    2014-01-01

    Summary Cushing’s syndrome, induced by an endogenous or exogenous cortisol excess, and acromegaly, the clinical syndrome caused by growth hormone (GH) excess in adulthood, as well as the disease induced by GH deficiency (GHD), represent perfect models for the evaluation of the effects induced by chronic exposure in vivo, respectively, to cortisol and GH/IGF-1 excess or deficiency on the complex structure of the tendons as well as on the related post-traumatic repair mechanism. Although the literature is still scant, here in main scientific evidence on this topic is summarized in order to provide suggestions about the management of the above mentioned illnesses, to translate such information in the field of sports medicine and/or traumatology, and to increase and to disseminate knowledge on this misunderstood theme. PMID:25489551

  9. Prestressed concrete using KEVLAR reinforced tendons

    SciTech Connect

    Dolan, C.W.

    1989-01-01

    KEVLAR is a high strength, high modulus synthetic fiber manufactured by the E.I. DuPont de Nemours Company. The fiber is resistant to chloride and alkali attack. The resistance is enhanced when the fibers are assembled into a resin matrix and fabricated as rods. These properties suggest that KEVLAR reinforced rods may be a substitute for high strength steel prestress tendons in certain applications such as bridge decks and parking structures. This dissertation presents the background, theoretical development, and experimental investigations of KEVLAR reinforced rod strength, anchorage, fabrication and performance in prestressed concrete structures. The study concludes that KEVLAR has significant potential for these prestressed concrete applications. However, the reliability of the long term anchorage of the KEVLAR reinforced rods must be improved before production applications are undertaken. KEVLAR has a low shear strength compared to its tensile capacity. The anchorage of KEVLAR reinforced rods is sensitive to the shear forces generated in the anchorage assembly. Finite element analyses, using interface elements to simulate the addition of a mold release agent in a conic anchor, predict the behavior of resin socketed anchors. Test results confirm that mold release agents reduce the anchor shear stresses and suggest that moderate strength resins may be used in the anchor. KEVLAR is nearly linearly elastic to failure, yet ductility of a structure is an important design concern. Prestressed concrete beam tests using both bonded and unbonded tendons demonstrated that ductile structural behavior is obtained. Methods of predicting the strength and deflection behavior of the prestressed beams are presented and the theoretical predictions are compared to the experimental results. The overall correlation between predicted and theoretical results is satisfactory.

  10. Neoclassical Tearing Modes and Their Control

    NASA Astrophysics Data System (ADS)

    La Haye, R. J.

    2005-10-01

    A principal pressure limit in tokamaks is set by the onset of neoclassical tearing modes (NTMs), which are destabilized and maintained by helical perturbations to the pressure- gradient driven ``bootstrap" current. The resulting magnetic islands break up the magnetic surfaces that confine the plasma. The NTM is linearly stable but nonlinearly unstable, and generally requires a ``seed" to destabilize a metastable state. In the past decade, NTM physics has been studied and its effects identified as performance-degrading in many tokamaks, including ASDEX Upgrade, COMPASS-D, DIII-D, JET, JT-60U, MAST, NSTX, T-10, TCV, TEXTOR, and TFTR. The validation of NTM physics, suppressing the NTMs, and/or avoiding them altogether are areas of active study and considerable progress. Recent joint experiments on ASDEX Upgrade, DIII-D, and JET, for example, give new insight into the underlying physics, seeding, and threshold scaling of NTMs. The physics scales towards increased NTM susceptibility in ITER, underlining the importance of both further study and development of control strategies. These strategies include regulation of ``sawteeth" to reduce seeding, using static ``bumpy" magnetic fields to interfere with the perturbed bootstrap current, and/or applying precisely located microwave power current drive at an island to stabilize (or avoid destabilization of) the NTM. Sustained stable operation without the highly deleterious m=2, n=1 island has been achieved, for example, at a pressure consistent with the no-wall n=1 ideal kink limit, by using electron cyclotron current drive at the q=2 rational surface, which is found by real-time accurate equilibrium reconstruction. This improved understanding of NTM physics and stabilization strategies will allow design of NTM control methods for future burning-plasma experiments like ITER.

  11. Neoclassical tearing modes and their controla)

    NASA Astrophysics Data System (ADS)

    La Haye, R. J.

    2006-05-01

    A principal pressure limit in tokamaks is set by the onset of neoclassical tearing modes (NTMs), which are destabilized and maintained by helical perturbations to the pressure-gradient driven "bootstrap" current. The resulting magnetic islands break up the magnetic surfaces that confine the plasma. The NTM is linearly stable but nonlinearly unstable, and generally requires a "seed" to destabilize a metastable state. In the past decade, NTM physics has been studied and its effects identified as performance degrading in many tokamaks. The validation of NTM physics, suppressing the NTMs, and/or avoiding them altogether are areas of active study and considerable progress. Recent joint experiments give new insight into the underlying physics, seeding, and threshold scaling of NTMs. The physics scales toward increased NTM susceptibility in ITER, underlying the importance of both further study and development of control strategies. These strategies include regulation of "sawteeth" to reduce seeding, using static "bumpy" magnetic fields to interfere with the perturbed bootstrap current, and/or applying precisely located microwave power current drive at an island to stabilize (or avoid destabilization of) the NTM. Sustained stable operation without the highly deleterious m =2, n =1 island has been achieved at a pressure consistent with the no-wall n =1 ideal kink limit, by using electron cyclotron current drive at the q =2 rational surface, which is found by real-time accurate equilibrium reconstruction. This improved understanding of NTM physics and stabilization strategies will allow design of NTM control methods for future burning-plasma experiments like ITER.

  12. A model of muscle-tendon function in human walking

    E-print Network

    Endo, Ken

    In this paper, we study the mechanical behavior of leg muscles and tendons during human walking in order to motivate the design of economical robotic legs. We hypothesize that quasi-passive, series-elastic clutch units ...

  13. Cellular therapy in bone-tendon interface regeneration

    PubMed Central

    Rothrauff, Benjamin B; Tuan, Rocky S

    2014-01-01

    The intrasynovial bone-tendon interface is a gradual transition from soft tissue to bone, with two intervening zones of uncalcified and calcified fibrocartilage. Following injury, the native anatomy is not restored, resulting in inferior mechanical properties and an increased risk of re-injury. Recent in vivo studies provide evidence of improved healing when surgical repair of the bone-tendon interface is augmented with cells capable of undergoing chondrogenesis. In particular, cellular therapy in bone-tendon healing can promote fibrocartilage formation and associated improvements in mechanical properties. Despite these promising results in animal models, cellular therapy in human patients remains largely unexplored. This review highlights the development and structure-function relationship of normal bone-tendon insertions. The natural healing response to injury is discussed, with subsequent review of recent research on cellular approaches for improved healing. Finally, opportunities for translating in vivo findings into clinical practice are identified. PMID:24326955

  14. Osmotic pressure induced tensile forces in tendon collagen

    E-print Network

    Masic, Admir

    Water is an important component of collagen in tendons, but its role for the function of this load-carrying protein structure is poorly understood. Here we use a combination of multi-scale experimentation and computation ...

  15. Peroneus Brevis Tendon Variant Insertion on the Calcaneus

    PubMed Central

    Cecava, Nathan D.; Campbell, Scot E.

    2015-01-01

    Insertion of the peroneus brevis tendon normally occurs at the lateral aspect of the fifth metatarsal base. However, there is new evidence that congenital variant insertion of the tendon on the calcaneal peroneal tubercle occurs in a small segment of the population. We report a case of 24-year old male presenting with non-traumatic ankle pain who underwent ankle magnetic resonance imaging. Imaging demonstrated insertion of the peroneus brevis tendon on the calcaneal peroneal tubercle with absence of the tendon distal to the calcaneus. Furthermore, in reviewing 200 consecutive ankle magnetic resonance examinations, the authors discovered one additional case of this variant. We discuss the magnetic resonance imaging characteristics of this anatomic variant, the implications for clinical management, and review the literature on peroneal anatomic variations.

  16. A model of muscle-tendon function in human walking

    E-print Network

    Endo, Ken, Ph. D. Massachusetts Institute of Technology

    2012-01-01

    In order to motivate the design of legged machines that walk as humans do, this thesis investigates how leg muscles and tendons work mechanically during level-ground human walking at self-selected speeds. I hypothesize ...

  17. Mechanical properties of the patellar tendon in adults and children.

    PubMed

    O'Brien, Thomas D; Reeves, Neil D; Baltzopoulos, Vasilios; Jones, David A; Maganaris, Constantinos N

    2010-04-19

    It is not currently known how the mechanical properties of human tendons change with maturation in the two sexes. To address this, the stiffness and Young's modulus of the patellar tendon were measured in men, women, boys and girls (each group, n=10). Patellar tendon force (F(pt)) was calculated from the measured joint moment during a ramped voluntary isometric knee extension contraction, the antagonist knee extensor muscle co-activation quantified from its electromyographical activity, and the patellar tendon moment arm measured from magnetic resonance images. Tendon elongation was imaged using the sagittal-plane ultrasound scans throughout the contraction. Tendon cross-sectional area was measured at rest from ultrasound scans in the transverse plane. Maximal F(pt) and tendon elongation were (mean+/-SE) 5453+/-307 N and 5+/-0.5 mm for men, 3877+/-307 N and 4.9+/-0.6 mm for women, 2017+/-170 N and 6.2+/-0.5 mm for boys and 2169+/-182 N and 5.9+/-0.7 mm for girls. In all groups, tendon stiffness and Young's modulus were examined at the level that corresponded to the maximal 30% of the weakest participant's F(pt) and stress, respectively; these were 925-1321 N and 11.5-16.5 MPa, respectively. Stiffness was 94% greater in men than boys and 84% greater in women than girls (p<0.01), with no differences between men and women, or boys and girls (men 1076+/-87 N/mm; women 1030+/-139 N/mm; boys 555+/-71 N/mm and girls 561.5+/-57.4 N/mm). Young's modulus was 99% greater in men than boys (p<0.01), and 66% greater in women than girls (p<0.05). There were no differences in modulus between men and women, or boys and girls (men 597+/-49 MPa; women 549+/-70 MPa; boys 255+/-42 MPa and girls 302+/-33 MPa). These findings indicate that the mechanical stiffness of tendon increases with maturation due to an increased Young's modulus and, in females due to a greater increase in tendon cross-sectional area than tendon length. PMID:20045111

  18. Direct Repair without Augmentation of Patellar Tendon Avulsion following TKA

    PubMed Central

    Kumar, Nishikant; Yadav, Chandrashekhar; Kumar, Ashok

    2015-01-01

    Complications involving the extensor mechanism after TKA are potentially disastrous. We are reporting a case of patellar tendon rupture from tibial tuberosity following total knee arthroplasty. We managed it by direct repair with fiberwire using Krackow suture technique without augmentation. Our long term result has been very encouraging. Our method is a safe and better method of management of patellar tendon avulsion following TKA when it happens without any tissue loss. PMID:25632362

  19. Tendon Transfers Around the Foot: When and Where.

    PubMed

    Kuo, Ken N; Wu, Kuan-Wen; Krzak, Joseph J; Smith, Peter A

    2015-12-01

    Tendon transfers are invaluable in the treatment of severe children's foot deformities. They are often preferable to simple releases, lengthening, or fusion in surgical treatment because they provide an active motor function for deformity correction and, when properly selected, the procedures stabilize the foot against progressive deformity. The authors describe 4 commonly used tendon transfer procedures that are useful in children's foot deformity surgeries. PMID:26589081

  20. Tear Film Breakup and Structure Studied by Simultaneous Video Recording of Fluorescence and Tear Film Lipid Layer Images

    PubMed Central

    King-Smith, P. Ewen; Reuter, Kathleen S.; Braun, Richard J.; Nichols, Jason J.; Nichols, Kelly K.

    2013-01-01

    Purpose. The thinning of the precorneal tear film between blinks and tear film breakup can be logically analyzed into contributions from three components: evaporation, flow into the cornea, and tangential flow along the corneal surface. Whereas divergent tangential flow contributes to certain types of breakup, it has been argued that evaporation is the main cause of tear thinning and breakup. Because evaporation is controlled by the tear film lipid layer (TFLL) it should therefore be expected that patterns of breakup should match patterns in the TFLL, and this hypothesis is tested in this study. Methods. An optical system is described for simultaneous video imaging of fluorescein tear film breakup and the TFLL. Recordings were made from 85 subjects, including both with healthy and dry eyes. After instillation of 5 ?L2% fluorescein, subjects were asked to blink 1 second after the start of the recording and try to maintain their eyes open for the recording length of 30 or 60 seconds. Results. Areas of tear film thinning and breakup usually matched corresponding features in the TFLL. Whereas thinning and breakup were often matched to thin lipid, surprisingly, the corresponding lipid region was not always thinner than the surrounding lipid. Occasionally, a thin lipid region caused a corresponding region of greater fluorescence (thicker aqueous layer), due to convergent tangential flow. Conclusions. Areas of tear thinning and breakup can generally be matched to corresponding regions of the TFLL as would be expected if breakup is largely due to evaporation. Surprisingly, in some examples, the corresponding lipid area was not thinner and possibly thicker than the surrounding lipid. This indicates that the lipid was a poor barrier to evaporation, perhaps because of deficiency in composition and/or structure. For example, bacterial lipases may have broken down esters into component acids and alcohols, causing a defective TFLL structure with increased evaporation. PMID:23766476

  1. Evaluation of the phenol red thread tear test in falconiformes.

    PubMed

    Smith, Stephen P; Barbon, Alberto Rodriguez; Forbes, Neil A

    2015-03-01

    Falconiformes are active searchers and hunters that require visual precision to catch their prey and survive in the wild. Despite this, ocular disease is likely to be underdiagnosed in these species, at least in part because of limited proven diagnostic methods and lack of published scientific data. Tear film deficiency is recognized as an important ocular surface disease in dogs but has not been well evaluated in birds. To evaluate the phenol red thread (PRT) tear test as an alternative method to the Schirmer tear test (STT) for determining tear production in Falconiformes, we assessed the PRT tear test twice for each eye in 21 birds from the genus Falco. The mean PRT test values for the right (OD) and left (OS) eyes were OD=30.2±4.6 mm/15 s and OS=29.1±3.7 mm/15 s, with an overall PRT test value for both eyes (OU) of 30.6±4.2 mm/15 s. Good reproducibility was seen with the PRT test as shown by the strong positive correlation between the first and second tests in the birds. The PRT test method provides repeatable results that are easy to obtain, easy to read, and achieved under the same conditions as the STT. PMID:25867663

  2. Dog Tear Film Proteome In-Depth Analysis

    PubMed Central

    Winiarczyk, Mateusz; Winiarczyk, Dagmara; Banach, Tomasz; Adaszek, Lukasz; Madany, Jacek; Mackiewicz, Jerzy; Pietras-Ozga, Dorota; Winiarczyk, Stanislaw

    2015-01-01

    In this study, mass spectrometry was used to explore the canine tear proteome. Tear samples were obtained from six healthy dogs, and one-dimensional sodium dodecyl sulphate polyacrylamide gel electrophoresis (1D SDS-PAGE) was used as a first step to separate intact proteins into 17 bands. Each fraction was then trypsin digested and analysed by matrix-assisted laser desorption/ionization time-of-flight tandem mass spectrometry (MALDI-TOF-MS/MS) to characterize the protein components in each fraction. In total, 125 tear proteins were identified, with MCA (Major Canine Allergen), Serum albumin, UPF0557 protein C10orf119 homolog, Collagen alpha-2(I) chain, Tyrosine -protein kinase Fer, Keratine type II cytoskeletal, Beta-crystallin B2, Interleukin-6 and Desmin occuring as the most confident ones with the highest scores. The results showed that the proteomic strategy used in this study was successful in the analysis of the dog tear proteome. To the best of our knowledge, this study is the first to report the comprehensive proteome profile of tears from healthy dogs by 1D SDS PAGE and MALDI-TOF. Data are available via ProteomeXchange with identifier PXD003124. PMID:26701646

  3. Non invasive assessment of the human tear film dynamics.

    PubMed

    Ring, M H; Rabensteiner, D F; Horwath-Winter, J; Boldin, I; Schrödl, F; Reitsamer, H; Haslwanter, T

    2015-11-01

    Dry eye disease, or keratoconjunctivitis sicca, is a multifactorial syndrome with altered tear film homeostasis leading to ocular irritations. These alterations cause discomfort and stress for the patient, but only a few objective parameters allow for proper differential diagnosis into different subtypes of this condition. The mostly invasively performed standard assessment procedures for tear film diagnosis are manifold, but often correlate quite poorly with the subjectively reported symptoms. Due to the inherent limitations, e.g. the subjectivity of the commonly performed invasive tests, a number of devices have been developed to assess the human tear film non-invasively. Since the production, delivery, distribution and drainage of the tear film is a dynamic process, we have focused our review on non-invasive methods which are capable of continuous or repetitive observations of the tear film during an inter-blink interval. These dynamic methods include (1) Interferometry, (2) Pattern Projection, (3) Aberrometry, (4) Thermography; and (5) Evaporimetry. These techniques are discussed with respect to their diagnostic value, both for screening and differential diagnostic of Dry Eye Disease. Many of the parameters obtained from these tests have been shown to have the potential to reliably discriminate patients from healthy subjects, especially when the tests are performed automatically and objectively. The differentiation into subtypes based solely on a single, dynamic parameter may not be feasible, but the combination of non-invasively performed procedures may provide good discrimination results. PMID:26406882

  4. Hot Tearing Susceptibility of Mg-Ca Binary Alloys

    NASA Astrophysics Data System (ADS)

    Song, Jiangfeng; Wang, Zhi; Huang, Yuanding; Srinivasan, Amirthalingam; Beckmann, Felix; Kainer, Karl Ulrich; Hort, Norbert

    2015-12-01

    Hot tearing is known as one of the most critical solidification defects commonly encountered during casting practice. As most Mg alloys are initially prepared by casting, ingots must have superior quality with no casting defects for the further processing. Due to the extensive potential biodegradable applications of binary Mg-Ca alloys, it is of great importance to investigate their hot tearing behavior. In the present study, the influence of Ca content (0.1, 0.2, 0.5, 1.0, and 2.0 wt pct) on hot tearing susceptibility (HTS) of Mg-Ca binary alloys was investigated using a constrained rod casting apparatus equipped with a load cell and data acquisition system. Tear volumes were quantified with 3D X-ray tomography. Results showed that the influence of Ca content on HTS followed a "?" shape: the HTS increased with increase in Ca content, reached a maximum at 0.5 to 1 wt pct Ca, and then decreased with further increasing the Ca content to 2.0 wt pct. The wide solidification range and reasonably high volume of intermetallic in the Mg-0.5 wt pct Ca and Mg-1 wt pct Ca alloys resulted in high HTS. Microstructure analysis suggested that the hot tear initiated at grain boundaries and propagated along them through thin film rupture or across the eutectic.

  5. Tearing resistance of some co-polyester sheets

    SciTech Connect

    Kim, Ho Sung; Karger-Kocsis, Jozsef

    2004-06-07

    A three-zone model consisting of initial, evolutionary and stabilised plastic zones for tearing resistance was proposed for polymer sheets. An analysis with the model, based on the essential work of fracture (EWF) approach, was demonstrated to be capable for predicting specific total work of fracture along the tear path across all the plastic zones although accuracy of specific essential work of fracture is subject to improvement. Photo-elastic images were used for identification of plastic deformation sizes and profiles. Fracture mode change during loading was described in relation with the three zones. Tearing fracture behaviour of extruded mono- and bi-layer sheets of different types of amorphous co-polyesters and different thicknesses was investigated. Thick material exhibited higher specific total work of tear fracture than thin mono-layer sheet in the case of amorphous polyethylene terephthalate (PET). This finding was explained in terms of plastic zone size formed along the tear path, i.e., thick material underwent larger plastic deformation than thin material. When PET and polyethylene terephthalate glycol (PETG) were laminated with each other, specific total work of fracture of the bi-layer sheets was not noticeably improved over that of the constituent materials.

  6. Molecular Organization of the Tear Fluid Lipid Layer

    PubMed Central

    Kulovesi, Pipsa; Telenius, Jelena; Koivuniemi, Artturi; Brezesinski, Gerald; Rantamäki, Antti; Viitala, Tapani; Puukilainen, Esa; Ritala, Mikko; Wiedmer, Susanne K.; Vattulainen, Ilpo; Holopainen, Juha M.

    2010-01-01

    The tear fluid protects the corneal epithelium from drying out as well as from invasion by pathogens. It also provides cell nutrients. Similarly to lung surfactant, it is composed of an aqueous phase covered by a lipid layer. Here we describe the molecular organization of the anterior lipid layer of the tear film. Artificial tear fluid lipid layers (ATFLLs) composed of egg yolk phosphatidylcholine (60 mol %), free fatty acids (20 mol %), cholesteryl oleate (10 mol %), and triglycerides (10 mol %) were deposited on the air-water interface and their physico-chemical behavior was compared to egg-yolk phosphatidylcholine monolayers by using Langmuir-film balance techniques, x-ray diffraction, and imaging techniques as well as in silico molecular level simulations. At low surface pressures, ATFLLs were organized at the air-water interface as heterogeneous monomolecular films. Upon compression the ATFLLs collapsed toward the air phase and formed hemispherelike lipid aggregates. This transition was reversible upon relaxation. These results were confirmed by molecular-level simulations of ATFLL, which further provided molecular-scale insight into the molecular distributions inside and dynamics of the tear film. Similar type of behavior is observed in lung surfactant but the folding takes place toward the aqueous phase. The results provide novel information of the function of lipids in the tear fluid. PMID:20959097

  7. Giant cell tumour of tendon sheath with simultaneous two tendon involvement of the foot treated with excision of the tumour and reconstruction of the flexor retinaculum using tibialis posterior tendon in a paediatric patient: A rare case report.

    PubMed

    Tiwari, Vivek; Ansari, Tahir; Mittal, Samarth; Sharma, Pankaj; Nalwa, Aasma

    2015-12-01

    Giant cell tumour of tendon sheath is a benign soft tissue tumour arising from the tendon sheath. The involvement of foot and ankle by such tumours is relatively rare. Children are not commonly afflicted by this condition. All such tumours are reported to arise either from a single tendon sheath or one joint. We report a case of giant cell tumour of tendon sheath in a 12-year-old child, arising simultaneously from the tendon sheaths of tibialis posterior and flexor digitorum longus tendons, as well as extending into the ankle joint. It was treated by complete excision of the mass along with the tendon sheaths with reconstruction of the flexor retinaculum. The location of the tumour, age of the patient, diffuse nature of the tumour and novel technique of reconstruction of the flexor retinaculum make this case extremely rare and the first to be reported in literature. PMID:26564735

  8. Substantial creep in healing human Achilles tendons. A pilot study

    PubMed Central

    Aspenberg, Per; Schepull, Thorsten

    2015-01-01

    Summary Background healing after rupture of the Achilles tendon can be described in terms of mechanical properties of the new-formed tissue, constituting the tendon callus. In previous human studies, the elastic modulus and the density remained almost constant during 3 months after mobilization started, and then improved up to one year. So far, time-dependent deformation of the healing human tendon has not been reported. Methods in a series of 16 patients, operated with Achilles tendon suture, we implanted tantalum beads into the tendon and measured the distance between them repeatedly during 3 min of constant loading, using an ordinary image intensifier. The patients unloaded their leg for 30 min before the test. To avoid bias, all images were investigated in a randomized and blinded order. Results total strain during 3 min of constant loading at 7 weeks post injury amounted to 5%, and at 19 weeks to 3%. About half of the strain, after the loading was applied, occurred during the second and third min. Considerable strain also occurred just before loading, when the patient was told that a load would be applied, but before this was actually done. Conclusion the measurements were crude, and this study should be seen as a pilot. Still, visco-elastic properties seem to dominate the mechanical behavior the healing Achilles tendon from start of mobilization to 19 weeks, at least when tested after 30 min rest. This deserves further studies with more precise methods. PMID:26605187

  9. Tendon Tissue Engineering: Progress, Challenges, and Translation to the Clinic

    PubMed Central

    Shearn, Jason T.; Kinneberg, Kirsten R.C.; Dyment, Nathaniel A.; Galloway, Marc T.; Kenter, Keith; Wylie, Christopher; Butler, David L.

    2013-01-01

    The tissue engineering field has made great strides in understanding how different aspects of tissue engineered constructs (TECs) and the culture process affect final tendon repair. However, there remain significant challenges in developing strategies that will lead to a clinically effective and commercially successful product. In an effort to increase repair quality, a better understanding of normal development, and how it differs from adult tendon healing, may provide strategies to improve tissue engineering. As tendon tissue engineering continues to improve, the field needs to employ more clinically relevant models of tendon injury such as degenerative tendons. We need to translate successes to larger animal models to begin exploring the clinical implications of our treatments. By advancing the models used to validate our TECs, we can help convince our toughest customer, the surgeon, that our products will be clinically efficacious. As we address these challenges in musculoskeletal tissue engineering, the field still needs to address the commercialization of products developed in the laboratory. TEC commercialization faces numerous challenges because each injury and patient is unique. This review aims to provide tissue engineers with a summary of important issues related to engineering tendon repairs and potential strategies for producing clinically successful products. PMID:21625053

  10. Proximal humerus shaft fracture after pectoralis major tendon rupture repair.

    PubMed

    Silverstein, Jeff A; Goldberg, Ben; Wolin, Preston

    2011-06-01

    Surgical repair of a complete pectoralis major tendon rupture at the humeral insertion has superior results compared to nonoperative treatment. To our knowledge, a proximal humerus shaft fracture occurring at the site of the bone trough and cortical drill holes after a pectoralis major tendon rupture repair has not been reported in the literature.A 45-year-old man sustained an acute left pectoralis major tendon rupture at the humeral insertion while performing a bench press maneuver. He underwent acute surgical repair. Approximately 8 weeks postoperatively, the patient fell from a standing height and sustained a proximal humerus shaft fracture through the repair site at the bone trough. Three days after the fracture, the patient underwent open reduction and internal fixation of the proximal humerus shaft fracture and exploration of the pectoralis major tendon repair. The fracture was found to be at the level of the repair site, and the pectoralis major tendon was completely intact to the distal fragment. The fracture healed uneventfully, and the patient regained full motion and strength of his extremity with no limitations.Any type of surgical fixation that creates a hole in the humerus or decreases the cross-sectional area such as a bone trough creates a stress riser. Patients undergoing pectoralis tendon repair that involves violating the humerus with a bone trough or hole have a slight risk of postoperative humerus fracture, especially if sustaining an early traumatic event such as a fall. PMID:21667914

  11. 26 CFR 1.1016-3 - Exhaustion, wear and tear, obsolescence, amortization, and depletion for periods since February...

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 2014-04-01 false Exhaustion, wear and tear, obsolescence, amortization...Application § 1.1016-3 Exhaustion, wear and tear, obsolescence, amortization...property shall be decreased for exhaustion, wear and tear, obsolescence,...

  12. 26 CFR 1.1016-3 - Exhaustion, wear and tear, obsolescence, amortization, and depletion for periods since February...

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 2013-04-01 false Exhaustion, wear and tear, obsolescence, amortization...Application § 1.1016-3 Exhaustion, wear and tear, obsolescence, amortization...property shall be decreased for exhaustion, wear and tear, obsolescence,...

  13. 26 CFR 1.1016-3 - Exhaustion, wear and tear, obsolescence, amortization, and depletion for periods since February...

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 2012-04-01 false Exhaustion, wear and tear, obsolescence, amortization...Application § 1.1016-3 Exhaustion, wear and tear, obsolescence, amortization...property shall be decreased for exhaustion, wear and tear, obsolescence,...

  14. 26 CFR 1.1016-4 - Exhaustion, wear and tear, obsolescence, amortization, and depletion; periods during which income...

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 2014-04-01 false Exhaustion, wear and tear, obsolescence, amortization...Application § 1.1016-4 Exhaustion, wear and tear, obsolescence, amortization...Adjustments to basis must be made for exhaustion, wear and tear, obsolescence,...

  15. 26 CFR 1.1016-3 - Exhaustion, wear and tear, obsolescence, amortization, and depletion for periods since February...

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 2011-04-01 false Exhaustion, wear and tear, obsolescence, amortization...Application § 1.1016-3 Exhaustion, wear and tear, obsolescence, amortization...property shall be decreased for exhaustion, wear and tear, obsolescence,...

  16. 26 CFR 1.1016-3T - Exhaustion, wear and tear, obsolescence, amortization, and depletion for periods since February...

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 2013-04-01 false Exhaustion, wear and tear, obsolescence, amortization...Application § 1.1016-3T Exhaustion, wear and tear, obsolescence, amortization...amount properly allowable for exhaustion, wear and tear, obsolescence,...

  17. 26 CFR 1.1016-4 - Exhaustion, wear and tear, obsolescence, amortization, and depletion; periods during which income...

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 2011-04-01 false Exhaustion, wear and tear, obsolescence, amortization...Application § 1.1016-4 Exhaustion, wear and tear, obsolescence, amortization...Adjustments to basis must be made for exhaustion, wear and tear, obsolescence,...

  18. 26 CFR 1.1016-4 - Exhaustion, wear and tear, obsolescence, amortization, and depletion; periods during which income...

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 2012-04-01 false Exhaustion, wear and tear, obsolescence, amortization...Application § 1.1016-4 Exhaustion, wear and tear, obsolescence, amortization...Adjustments to basis must be made for exhaustion, wear and tear, obsolescence,...

  19. 26 CFR 1.1016-3T - Exhaustion, wear and tear, obsolescence, amortization, and depletion for periods since February...

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 2012-04-01 false Exhaustion, wear and tear, obsolescence, amortization...Application § 1.1016-3T Exhaustion, wear and tear, obsolescence, amortization...amount properly allowable for exhaustion, wear and tear, obsolescence,...

  20. 26 CFR 1.1016-4 - Exhaustion, wear and tear, obsolescence, amortization, and depletion; periods during which income...

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 2010-04-01 true Exhaustion, wear and tear, obsolescence, amortization...Application § 1.1016-4 Exhaustion, wear and tear, obsolescence, amortization...Adjustments to basis must be made for exhaustion, wear and tear, obsolescence,...

  1. 26 CFR 1.1016-4 - Exhaustion, wear and tear, obsolescence, amortization, and depletion; periods during which income...

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 2013-04-01 false Exhaustion, wear and tear, obsolescence, amortization...Application § 1.1016-4 Exhaustion, wear and tear, obsolescence, amortization...Adjustments to basis must be made for exhaustion, wear and tear, obsolescence,...

  2. Collagen fibril diameter distribution in patellar tendon autografts after posterior cruciate ligament reconstruction in sheep: changes over time.

    PubMed Central

    Moeller, H D; Bosch, U; Decker, B

    1995-01-01

    The alterations in collagen fibril diameter distribution, mean fibril diameter and the area occupied by collagen after posterior cruciate ligament reconstruction using a patellar tendon autograft were estimated 2, 6, 16, 26, 52 and 104 wk postoperatively. Patellar tendons and posterior cruciate ligaments from unoperated animals were used as control tissues. Collagen fibrils were divided into histograms according to their diameter in order to analyse distribution maxima. There was a significant decrease in mean fibril diameter of the grafts in comparison with the control tissues. At 104 wk it was only about 51% of that for control posterior cruciate ligaments. The total area occupied by collagen was significantly reduced at 6 wk postoperatively and was about 57% in comparison with normal posterior cruciate ligaments. A considerable increase of small diameter collagen fibrils together with a loss of large fibrils was responsible for these results. There was no evidence of reestablishment of large diameter fibrils, which are normally found in tendon and ligaments, up to 2 y after transplantation. The total area covered by collagen was still reduced at this stage although the number of fibrils had increased. Images Fig. 1 Fig. 2 Fig. 3 PMID:7591977

  3. Modelling the evaporation of a tear film over a contact lens.

    PubMed

    Talbott, Kevin; Xu, Amber; Anderson, Daniel M; Seshaiyer, Padmanabhan

    2015-06-01

    A contact lens (CL) separates the tear film into a pre-lens tear film (PrLTF), the fluid layer between the CL and the outside environment, and a post-lens tear film (PoLTF), the fluid layer between the CL and the cornea. We examine a model for evaporation of a PrLTF on a modern permeable CL allowing fluid transfer between the PrLTF and the PoLTF. Evaporation depletes the PrLTF, and continued evaporation causes depletion of the PoLTF via fluid loss through the CL. Governing equations include Navier-Stokes, heat and Darcy's equations for the fluid flow and heat transfer in the PrLTF and porous layer. The PoLTF is modelled by a fixed pressure condition on the posterior surface of the CL. The original model is simplified using lubrication theory for the PrLTF and CL applied to a sagittal plane through the eye. We obtain a partial differential equation (PDE) for the PrLTF thickness that is first-order in time and fourth-order in space. This model incorporates evaporation, conjoining pressure effects in the PrLTF, capillarity and heat transfer. For a planar film, we find that this PDE can be reduced to an ordinary differential equation (ODE) that can be solved analytically or numerically. This reduced model allows for interpretation of the various system parameters and captures most of the basic physics contained in the model. Comparisons of ODE and PDE models, including estimates for the loss of fluid through the lens due to evaporation, are given. PMID:24521538

  4. Conservative Management of an Iatrogenic Esophageal Tear in Kenya

    PubMed Central

    Waweru, Peter; Mwaniki, David

    2015-01-01

    Since its description over 250 years ago, diagnosis of esophageal perforation remains challenging, its management controversial, and its mortality high. This rare, devastating, mostly iatrogenic, condition can quickly lead to severe complications and death due to an overwhelming inflammatory response to gastric contents in the mediastinum. Diagnosis is made with the help of esophagograms and although such tears have traditionally been managed via aggressive surgical approach, recent reports emphasize a shift in favor of nonoperative care which unfortunately remains controversial. We here present a case of an iatrogenic esophageal tear resulting from a routine esophagoscopy in a 50-year-old lady presenting with dysphagia. The esophageal tear, almost missed, was eventually successfully managed conservatively, thanks to a relatively early diagnosis. PMID:26257974

  5. The role of thermal conduction in tearing mode theory

    NASA Astrophysics Data System (ADS)

    Connor, J. W.; Ham, C. J.; Hastie, R. J.; Liu, Y. Q.

    2015-06-01

    The role of anisotropic thermal diffusivity in tearing mode stability is analysed in general toroidal geometry following similar techniques to Glasser et al (1975 Phys. Fluids 18 875), although a stronger ordering of the plasma compressibility is required. Resistive layer equations are obtained for a resistive magnetohydrodynamic (MHD) model with anisotropic transport of pressure. A dispersion relation linking the growth rate to the tearing mode stability parameter, ??, characterising the external ideal MHD region, is derived. By using a resistive MHD code modified to include such thermal transport to calculate tearing mode growth rates, this dispersion relation is employed to determine ?? in situations with finite plasma pressure that are stabilised by favourable average curvature when using a simple resistive MHD code. We also demonstrate that the same code can be used to obtain the basis-functions (Ham et al 2012 Plasma Phys. Control. Fusion 54 105014) needed for an alternative approach to calculating ??.

  6. Patient Satisfaction after Arthroscopic Repair of Acetabular Labral Tears

    PubMed Central

    Ha, Yong-Chan; Shin, Yong-Eun

    2014-01-01

    Background Acetabular labral tear is a main cause of hip pain and disability, often requiring surgical treatment. Improvements of hip arthroscopic technique have produced positive outcomes after labral repair with arthroscopy. The purpose of this study was to determine clinical outcomes and patient satisfaction after arthroscopic repair of acetabular labral tear. Methods We interviewed 21 patients (10 men and 11 women; mean age, 36 years [range, 22 to 57 years]) with acetabular labral tears that had been repaired arthroscopically in terms of satisfaction of the procedure. In addition, clinical outcome was assessed using visual analog scale (VAS) score, University of California, Los Angeles (UCLA) activity, Western Ontario and McMaster Universities (WOMAC) osteoarthritis index, and Harris hip score, and radiologic outcome was assessed using serial radiography. The patients were followed for 24-50 months. Results The mean Harris hip score was 73 points (range, 64 to 84 points) preoperatively and 83 points (range, 66 to 95 points) postoperatively. Fifteen hips (71%) were rated excellent and good. The mean WOMAC osteoarthritis index and VAS scores were improved at final follow-up. UCLA activity at the latest follow-up improved in 16 patients. The Tonnis grade of osteoarthritis at the latest follow-up did not change in all patients. Eighteen of the patients (86%) were satisfied with the procedure. Conclusions High rate of satisfaction after arthroscopic repair of acetabular labral tears is an encouraging outcome. Arthroscopic treatment of labral tears might be a useful technique in patients with hip pathologies, such as femoroacetabular impingement with labral tears. PMID:24900896

  7. Nonlinear tearing instabilities in tokamaks with locally flattened current profiles

    SciTech Connect

    Reiman, A.H.

    1988-07-01

    Nonlinear tearing stability is evaluated for current profiles which are linearly stabilized by flattening the current in the neighborhood of the rational surface. When marginally stable to the linear instability, these profiles remain unstable in the presence of a small but finite island. The growth of the island saturated only when the island reaches the width it would have attained in the absence of flattening. Implications are discused for proposed methods of tearing mode stabilization and for theories of the tokamak sawtooth oscillation. 19 refs., 1 fig.

  8. Patellar Tendon–Trochlear Groove Angle Measurement

    PubMed Central

    Hinckel, Betina B.; Gobbi, Riccardo G.; Kihara Filho, Eduardo N.; Demange, Marco K.; Pécora, José Ricardo; Camanho, Gilberto Luis

    2015-01-01

    Background: The tibial tubercle–trochlear groove (TT-TG) is used as the gold standard for patellofemoral malalignment. Purpose: To assess 3 patellar tendon–trochlear groove (PT-TG) angle measurement techniques and the PT-TG distance measurement (tendinous cartilaginous TT-TG) as predictors of patellar instability. Study Design: Cohort study (diagnosis); Level of evidence, 3. Methods: Three PT-TG angle measurements and the PT-TG distance were measured in 82 participants with patellar instability and 100 controls using magnetic resonance imaging (MRI). Measurement landmarks were the line tangent to the posterior femoral condyles, the deepest point of the trochlea, the transepicondylar line, and the patellar tendon center. All measurements were recorded once by 1 examiner, and the measurements were recorded twice by 2 examiners in a random group of 100 knees. Mean values and standard deviations (SDs) were obtained. Normality cutoff values were defined as 2 and 3 SDs above the mean in the control group. The sensitivity, specificity, and positive likelihood ratio (LR+) were calculated. Inter- and intrarater reliability were assessed based on the intraclass correlation coefficient (ICC). Results: The measurements from the patellar instability and control groups, respectively, for angle 1 (16.4° and 8.4°), angle 2 (31° and 15.6°), angle 3 (30.8° and 15.7°), PT-TG distance (14.5 and 8.4 mm), and patellar tilt (21.1° and 7.5°) were significantly different (P < .05). The angle measurements showed greater sensitivity, specificity, and LR+ than the PT-TG distance. Inter- and intrarater ICC values were >0.95 for all measurements. Conclusion: The PT-TG angle and the PT-TG distance are reliable and are different between the patellar instability and control groups. PT-TG angles are more closely associated with patellar instability than PT-TG distance. Clinical Relevance: PT-TG angle measurements show high reliability and association with patellar instability and can aid in the assessment of extensor mechanism malalignment. A more sensitive and specific evaluation of extensor mechanism malalignment can improve patient care by preventing both redislocation and abnormal tracking of overlooked malalignment and complications of unnecessary tibial tuberosity medialization. PMID:26535396

  9. Effects of celecoxib on proliferation and tenocytic differentiation of tendon-derived stem cells

    SciTech Connect

    Zhang, Kairui; Zhang, Sheng; Li, Qianqian; Yang, Jun; Dong, Weiqiang; Wang, Shengnan; Cheng, Yirong; Al-Qwbani, Mohammed; Wang, Qiang; Yu, Bin

    2014-07-18

    Highlights: • Celecoxib has no effects on TDSCs cell proliferation in various concentrations. • Celecoxib reduced mRNAs levels of tendon associated transcription factor. • Celecoxib reduced mRNAs levels of main tendon associated collagen. • Celecoxib reduced mRNAs levels of tendon associated molecules. - Abstract: NSAIDs are often ingested to reduce the pain and improve regeneration of tendon after tendon injury. Although the effects of NSAIDs in tendon healing have been reported, the data and conclusions are not consistent. Recently, tendon-derived stem cells (TDSCs) have been isolated from tendon tissues and has been suggested involved in tendon repair. Our study aims to determine the effects of COX-2 inhibitor (celecoxib) on the proliferation and tenocytic differentiation of TDSCs. TDSCs were isolated from mice Achilles tendon and exposed to celecoxib. Cell proliferation rate was investigated at various concentrations (0.1, 1, 10 and 100 ?g/ml) of celecoxib by using hemocytometer. The mRNA expression of tendon associated transcription factors, tendon associated collagens and tendon associated molecules were determined by reverse transcription-polymerase chain reaction. The protein expression of Collagen I, Collagen III, Scleraxis and Tenomodulin were determined by Western blotting. The results showed that celecoxib has no effects on TDSCs cell proliferation in various concentrations (p > 0.05). The levels of most tendon associated transcription factors, tendon associated collagens and tendon associated molecules genes expression were significantly decreased in celecoxib (10 ?g/ml) treated group (p < 0.05). Collagen I, Collagen III, Scleraxis and Tenomodulin protein expression were also significantly decreased in celecoxib (10 ?g/ml) treated group (p < 0.05). In conclusion, celecoxib inhibits tenocytic differentiation of tendon-derived stem cells but has no effects on cell proliferation.

  10. Development of the shields for tendon injury repair using polyvinyl alcohol--hydrogel ( PVA-H).

    PubMed

    Kobayashi, M; Toguchida, J; Oka, M

    2001-01-01

    In recent years, marked advances have been made in repair techniques for tendon injury, but the treatment of finger flexor tendon injury is still one of the most difficult and important problems in the orthopedic field. The main problem in tendon repair is adhesion between the tendon and surrounding tissue. To prevent this adhesion and achieve tendon union, we developed adhesion preventive shields for tendon repair using polyvinyl alcohol hydrogel ( PVA-H) with 90% water content, and carried out an implant experiment using the deep flexor tendon of the third toe of domestic fowl. Injured tendons shielded with PVA-H showed union at about 3 weeks after the operation without adhesion to the surrounding tissue and good function such as gliding and range of motion. Neither breakage of the PVA-H shield itself nor infection, nor degeneration in the surrounding tissue were observed. These results confirmed that the tendon itself has repair ability, and the tendon is regenerated by synovial nutrition through PVA-H. High water content PVA-H may have clinically potential and be applicable to adhesion-preventive shields for tendon repair. However, re-rupture was observed, probably due to accidental tendon injury at an early period after the operation. In some cases, tendon immobilization methods to prevent re-rupture might be necessary. PMID:11410891

  11. Repopulation of Intrasynovial Flexor Tendon Allograft with Bone Marrow Stromal Cells: An Ex Vivo Model

    PubMed Central

    Amadio, Peter C.; Thoreson, Andrew R.; An, Kai-Nan

    2014-01-01

    Purpose: Delayed healing is a common problem whenever tendon allografts are used for tendon or ligament reconstruction. Repopulating the allograft with host cells may accelerate tendon regeneration, but cell penetration into the allograft tendon is limited. Processing the tendon surface with slits that guide cells into the allograft substrate may improve healing. The purpose of this study was to describe a surface modification of allograft tendon that includes slits to aid cell repopulation and lubrication to enhance tendon gliding. Methods: Canine flexor digitorum profundus tendons were used for this study. Cyclic gliding resistance was measured over 1000 cycles. Tensile stiffness was assessed for normal tendon, tendon decellularized with trypsin and Triton X-100 (decellularized group), tendon decellularized and perforated with multiple slits (MS group) and tendon decellularized, perforated with slits and treated with a carbodiimide-derivatized hyaluronic acid and gelatin (cd-HA-gelatin) surface modification (MS-SM group). To assess tendon repopulation, bone marrow stromal cells (BMSCs) were used in the decellularized and MS groups. DNA concentration and histology were evaluated and compared to normal tendons and nonseeded decellularized tendons. Results: The gliding resistance of the decellularized and MS groups was significantly higher compared with the normal group. There was no significant difference in gliding resistance between the decellularized and MS group. Gliding resistance of the normal group and MS-SM group was not significantly different. The Young's modulus was not significantly different among the four groups. The DNA concentration in the MS group was significantly lower than in normal tendons, but significantly higher than in decellularized tendons, with or without BMSCs. Viable BMSCs were found in the slits after 2 weeks in tissue culture. Conclusions: Tendon slits can successfully harbor BMSCs without compromising their survival and without changing tendon stiffness. Surface modification restores normal gliding function to the slit tendon. Clinical Relevance: A multislit tendon reseeded with BMSCs, with a surface treatment applied to restore gliding properties, may potentially promote tendon revitalization and accelerate healing for tendon or ligament reconstruction applications. PMID:24024566

  12. Quantitative ultrasound (QUS) assessment of tissue properties for Achilles tendons

    NASA Astrophysics Data System (ADS)

    Du, Yi-Chun; Chen, Yung-Fu; Chen, Pei-Jarn; Lin, Yu-Ching; Chen, Tainsong; Lin, Chii-Jeng

    2007-09-01

    Quantitative ultrasound (QUS) techniques have recently been widely applied for the characterization of tissues. For example, they can be used for the quantification of Achilles tendon properties based on the broadband ultrasound attenuation (BUA) and the speed of sound (SOS) when the ultrasound wave passes through the tissues. This study is to develop an integrated system to investigate the properties of Achilles tendons using QUS images from UBIS 5000 (DMS, Montpellier, France) and B-mode ultrasound images from HDI 5000 (ATL, Ultramark, USA). Subjects including young (32 females and 17 males; mean age: 23.7 ± 2.0) and middle-aged groups (8 female and 8 males; mean age: 47.3 ± 8.5 s) were recruited and tested for this study. Only subjects who did not exercise regularly and had no record of tendon injury were studied. The results show that the BUA is significantly higher for the young group (45.2 ± 1.6 dB MHz-1) than the middle-age group (40.5 ± 1.9 dB MHz-1), while the SOS is significantly lower for the young (1601.9 ± 11.2 ms-1) compared to the middle-aged (1624.1 ± 8.7 m s-1). On the other hand, the thicknesses of Achilles tendons for both groups (young: 4.31 ± 0.23 mm; middle age: 4.24 ± 0.23 mm) are very similar. For one patient who had an Achilles tendon lengthening (ATL) surgery, the thickness of the Achilles tendon increased from 4 mm to 4.33 mm after the surgery. In addition, the BUA increased by about 7.2% while the SOS decreased by about 0.6%. In conclusion, noninvasive ultrasonic assessment of Achilles tendons is useful for assisting clinical diagnosis and for the evaluation of a therapeutic regimen.

  13. Kinetic theory and simulation of collisionless tearing in bifurcated current sheets

    SciTech Connect

    Matsui, Tatsuki; Daughton, William

    2008-01-15

    Observations from the Earth's geomagnetic tail have established that the current sheet is often bifurcated with two peaks in the current density. These so-called bifurcated current sheets have also been reported in a variety of simulations and often occur in conjunction with significant temperature anisotropy. In this work, a new self-consistent Vlasov equilibrium is developed that permits both the current profile and temperature anisotropy to be independently adjusted. The stability of these layers with respect to the collisionless tearing mode is examined using both standard analytic techniques and a formally exact treatment involving a numerical evaluation of the full orbit integral. The resulting linear growth rate and mode structure are verified with fully kinetic particle-in-cell simulations. These results demonstrate that a bifurcated current profile has a strong stabilizing influence on the tearing mode in comparison to centrally peaked layers with a similar thickness. In contrast, electron temperature anisotropy is strongly destabilizing in the limit T{sub eperpendicular}>T{sub eparallel} and strongly stabilizing when T{sub eperpendicular}

  14. First-order finite-Larmor-radius effects on magnetic tearing in pinch configurations

    SciTech Connect

    King, J. R.; Mirnov, V. V.; Sovinec, C. R.

    2011-04-15

    The linear and nonlinear evolution of a single-helicity tearing mode in a cylindrical, force-free pinch are investigated using a fluid model with first-order finite-Larmor-radius corrections. Linear results computed with the nimrod[nonideal magnetohydrodynamics (MHD) with rotation, open discussion] code [Sovinec et al., J. Comput. Phys. 195, 355 (2004)] produce a regime at small {rho}{sub s} where the growth rate is reduced relative to resistive MHD, though the Hall term is not significant. The leading order contributions from ion gyroviscosity may be expressed as a drift associated with {nabla}B{sub 0} and poloidal curvature for experimentally relevant {beta}=0.1, S{approx}10{sup 5}-10{sup 6} force-free equilibria. The heuristic analytical dispersion relation, {gamma}{sup 4}({gamma}-i{omega}{sub *gv})={gamma}{sub MHD}{sup 5} where {omega}{sub *gv} is the gyroviscous drift frequency, confirms numerical results. The behavior of our cylindrical computations at large {rho}{sub s} corroborates previous analytic slab studies where an enhanced growth rate and radially localized Hall dynamo are predicted. Similar to previous drift-tearing results, nonlinear computations with cold ions demonstrate that the Hall dynamo is small when the island width is large in comparison with the scale for electron-ion coupling. The saturation is then determined by the resistive MHD physics. However, with warm ions the gyroviscous stress supplements the nonlinear Lorentz force, and the saturated island width is reduced.

  15. Two Fluid Dynamo and Edge-Resonant m=0 Tearing Instability in Reversed Field Pinch

    E-print Network

    Wisconsin at Madison, University of

    TH/P3-18 1 Two Fluid Dynamo and Edge-Resonant m=0 Tearing Instability in Reversed Field Pinch V of edge-resonant m=0 tearing modes. The key findings are: (1) two fluid effects are critical for dynamo through their influence on the phase between the fluctuations; in cylindrical RFP, the two fluid tearing

  16. Mass Spectral Determination of Fasting Tear Glucose Concentrations in Nondiabetic Volunteers, Justin T.

    E-print Network

    Asher, Sanford A.

    fluid samples obtained from 25 fasting study participants. Tear fluid was col- lected.01). Conclusions: Our tear fluid collection and analysis method enables reliable measurement of equilibrium for the monitoring of diabe- tes. Our methods are applicable for study of other tear fluid analytes and may prove

  17. Quantification of Total Particulate Matter and Benzene-Soluble Fraction Inhalation Exposures in Roofing Workers Performing Tear-off Activities.

    PubMed

    Hill, Ronald H; Ferraro, John R; Dodson, James L; Hockman, Edwin L; McGovern, Amy E; Fayerweather, William E

    2015-01-01

    Asphalt shingle removal (tear-off) from roofs is a major job task for an estimated 174,000 roofers in the United States. However, a literature search showed that there are no published studies that characterize worker inhalation exposures to asphalt particulates during shingle tear-off. To begin to fill this gap, the present study of inhalation exposures of roofers performing asphalt shingle tear-off was undertaken. The airborne agents of interest were total particulate matter (TP) and organic particulates measured as the benzene-soluble fraction (BSF) of total particulate. The study's objectives were to measure the personal breathing zone (PBZ) exposures of roofing tear-off workers to BSF and TP; and to assess whether these PBZ exposures are different from ambient levels. Task-based PBZ samples (typical duration 1-5 hours) were collected during asphalt shingle tear-off from roofs near Houston, Texas and Denver, Colorado. Samples were analyzed for TP and BSF using National Institute of Occupational Safety and Health (NIOSH) Method 5042. As controls, area samples (typical duration 3-6 hours) were collected on the ground near the perimeter of the tear-off project Because of the presence of significant sources of inorganic particulates in the work environment, emphasis was placed on the BSF data. No BSF exposure higher than 0.25 mg/m3 was observed, and 69% of the PBZ samples were below the limit of detection (LOD). Due to unforeseen confounding, however, statistical comparisons of on-the-roof PBZ samples with on-the-ground area samples posed some special challenges. This confounding grew out of the interaction of three factors: statistical censoring from the left; the strong inverse correlation between LOD concentration and sampling duration; and variation in sampling durations between on-the-ground area samples and on-the-roof PBZ samples. A general linear model analysis of variance (GLM-ANOVA) was applied to help address the confounding. The results of this analysis indicate that personal sample BSF results were not statistically significantly different from the background/area samples. PMID:26083058

  18. Ultrasound elastography for imaging tendons and muscles

    PubMed Central

    2012-01-01

    Ultrasound elastography is a recently developed ultrasound-based method which allows the qualitative or quantitative evaluation of the mechanical properties of tissue. Strain (compression) ultrasound elastography is the commonest technique performed by applying mild compression with the hand-held transducer to create real-time strain distribution maps, which are color-coded and superimposed on the B-mode images. There is increasing evidence that ultrasound elastography can be used in the investigation of muscle, tendon and soft tissue disease in the clinical practice, as a supplementary tool to conventional ultrasound examination. Based on preliminary data, potential clinical applications include early diagnosis, staging, and guiding interventions musculotendinous and neuromuscular disease as well as monitoring disease during rehabilitation. Ultrasound elastography could also be used for research into the biomechanics and pathophysiology of musculotendinous disease. Despite the great interest in the technique, there is still limited evidence in the literature and there are several technical issues which limit the reproducibility of the method, including differences in quantification methods, artefacts, limitations and variation in the application of the technique by different users. This review presents the published evidence on musculoskeletal applications of strain elastography, discusses the technical issues and future perspectives of this method and emphasizes the need for standardization and further research.

  19. Isolated rupture of the teres major tendon.

    PubMed

    Lester, Jonathan D; Boselli, Karen J; Kim, Paul D; Ahmad, Christopher S

    2010-11-01

    Acute isolated rupture of the teres major is an uncommon injury. This article presents the first report of midterm subjective and objective functional results following nonoperative management of an isolated teres major rupture. A 30-year-old right hand dominant man presented after a waterskiing traction injury to his left upper extremity. On physical examination, the patient had swelling and retraction of the teres major at the lower scapular border, which was accentuated with resisted adduction of the extremity. His teres major attachment at the humerus was not palpable. Magnetic resonance imaging revealed an isolated teres major tendon rupture. The patient was treated non-operatively with a rehabilitation protocol emphasizing rotator cuff, periscapular, and latissimus muscle strengthening. By 3 months postinjury, the patient had returned to all of his usual sporting activities, despite a persistent muscle retraction deformity over the teres major. At 3-year follow-up, the patient had no subjective complaints in the injured extremity and excellent functional outcome scores. A mean 37 kg loss of internal rotation strength (as measured by dynamometer) in the affected extremity with the arm abducted to 90° existed, although this difference was not subjectively appreciable. Although previously published reports have presented various options for the management of teres major injuries, the present case demonstrates that nonoperative treatment can produce excellent midterm subjective results in spite of objective internal rotation weakness. PMID:21053871

  20. Surgical Treatment of Synovial Chondromatosis of the Long Biceps Tendon Sheath

    PubMed Central

    Abay, Burak; Aksu, Neslihan; Soydan, Ramazan; Ercan, Ertu?rul; Kopuz, Cengiz

    2014-01-01

    Objectives: Primary synovial chondromatosis (PSC) is a rare benign neoplasm that affects diarthrodial joints. The reported cases of PSC in the literature are mostly localized in the knee, followed by the hip, elbow, wrist and shoulder. We report the surgical treatment of a rare case of PSC localized in the long biceps tendon sheath. Methods: A 66-year-old woman presented severe pain in her left shoulder without any traumatic event. The pain was rated on Visual analog scale (VAS) as 4 to 7. At the physical examination, a palpable mass was found medial to the bicipital groove of the left shoulder. Functional examination of the left shoulder revealed painful limitation at 150 abduction, at 130 forward elevation and at 40 external rotation. Constant Murley Score was measured as 65. A magnetic resonance image (MRI) revealed the presence of 2x2x1.8 cm lesion within the biceps tendon sheath, rotator cuff tear and a bone cyst in the great tubercule. The treatment of choice was the open surgical treatment with excision of the lesion, curettage and spongious allografting of the bony cyst and repair of the rotator cuff with two suture anchors. The histological examination was consistent with PSC without any malignant transformation. The shoulder was immobilized postoperatively for 2 days in a sling. Immediate passive ROM exercises were started at third day for 6 weeks. Results: At the 6 week follow-up, the patient achieved full symmetric restoration of motion. She had returned to full activity. Visual analog scale was rated 0 to 1 and Constant Murley Score was measured as 92. Functional examination of the left shoulder reveled 170 of abduction, at 160 forward elevation and at 40 external rotation. At 1-year follow-up, clinical findings were unremarkable, with no sign of recurrence. Conclusion: PSC is a benign, idiopathic lesion of the synovial membranes of the diarthrodial joints. PSC is observed rarely in extra-articular shoulder involvement. Although the diagnosis of PSC is often clear with the results of radiological and intraoperative findings, it needs to be verified histologically. Surgical treatment is preferred to avoid the risk of malignant transformation, possible damage to the neighboring anatomical structures and functional disability as seen in our patient.

  1. Diclofenac Patch for Treatment of Mild to Moderate Tendonitis or Bursitis

    ClinicalTrials.gov

    2008-08-05

    Rotator Cuff Tendonitis; Bicipital Tendonitis; Subdeltoid Bursitis of the Shoulder; Subacromial Bursitis of the Shoulder; Medial Epicondylitis of the Elbow; Lateral Epicondylitis of the Elbow; DeQuervain's Tenosynovitis of the Wrist

  2. Calibration of the mercury-in-silastic strain gauge in tendon load experiments.

    PubMed

    Riemersma, D J; Lammertink, J L

    1988-01-01

    A calibration method is presented by which the signals of mercury-in-silastic strain gauges (MISS), implanted in the tendons of in vitro loaded equine hindlegs, were converted to tendon loads. The relationships between MISS-signals and tendon loads were obtained from tensile-force tests applied to the tendons. Special attention was paid to the correction of the MISS-signals for amplitude-shifts resulting from internal repositioning of the MISS after tendon isolation and temperature differences. Shift corrections equivalent to tendon strains up to 2.8% were necessary in the in vitro experiment. The tendon loads deduced from the corrected MISS-signals were checked by torque analyses of the lower part of the limb. Differences between computed and experimentally obtained values of the torque of the tendon loads with respect to the fetlock joint ranged from -4 to +13%. PMID:3209592

  3. 77 FR 69508 - Inservice Inspection of Prestressed Concrete Containment Structures With Grouted Tendons

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-11-19

    ...Inservice Inspection of Prestressed Concrete Containment Structures With Grouted Tendons...Inservice Inspection of Prestressed Concrete Containment Structures with Grouted Tendons...surveillance program for prestressed concrete containment structures with grouted...

  4. The vasculature and its role in the damaged and healing tendon.

    PubMed

    Fenwick, Steven A; Hazleman, Brian L; Riley, Graham P

    2002-01-01

    Tendon pathology has many manifestations, from spontaneous rupture to chronic tendinitis or tendinosis; the etiology and pathology of each are very different, and poorly understood. Tendon is a comparatively poorly vascularised tissue that relies heavily upon synovial fluid diffusion to provide nutrition. During tendon injury, as with damage to any tissue, there is a requirement for cell infiltration from the blood system to provide the necessary reparative factors for tissue healing. We describe in this review the response of the vasculature to tendon damage in a number of forms, and how and when the revascularisation or neovascularisation process occurs. We also include a section on the revascularisation of tendon during its use as a tendon graft in both ligament reconstruction and tendon-tendon grafting. PMID:12106496

  5. The behavior of rotator cuff tendon cells in three-dimensional culture

    E-print Network

    Gill, Harmeet (Harmeet Kaur)

    2007-01-01

    The rotator cuff is composed of the supraspinatus, infraspinatus, subcapularis, and teres minor tendons. Rotator cuff injuries are common athletic and occupational injuries that surgery cannot fully repair. Therefore tendon ...

  6. Stop the Tears of Drug and Alcohol Abuse

    ERIC Educational Resources Information Center

    Shimon, Jane; Gibson, Terry-Ann; Spear, Caile

    2009-01-01

    Objectives: By participating in this Stop the Tears teaching strategy, students will be able to: (1) analyze how alcohol and drug abuse could affect their lives as well as the lives of their friends and family and, (2) create a media message, such as a poster, pamphlet, poem, or song, in which alcohol and drug prevention is advocated specific to…

  7. On the energy principle and ion tearing in the magnetotail

    NASA Technical Reports Server (NTRS)

    Brittnacher, M.; Quest, K. B.; Karimabadi, H.

    1994-01-01

    We re-examine the use of the energy principle as applied to the tearing instability in the magnetotail. We demonstrate that when a magnetic field component normal to the current sheet is present, electron pitch-angle diffusion (PAD) either by micro-turbulence or by chaotic orbits cannot remove the strong stabilization of the tearing mode caused by electron compressibility. We find that our conclusions are in agreement with those of Pellat et al. (1991), who argued on the basis of canonical P(sub y) conservation that the stabilization of the ion tearing mode cannot be removed by the introduction of PAD. Our results are at variance with those of Kuznetsova and Zelenyi (1991), who argued that the application of the energy principle used by Pellat et al. (1991) is incorrect, and that tearing is in fact unstable in the limit of strong PAD. We show that the disagreement between these two studies can be traced to an incorrect orbit evaluation first introduced by Coroniti (1980) and subnsequently used by Kuznetsova and Zelenyi (1991).

  8. From Onions to Shallots: Rewarding Tor Relays with TEARS

    E-print Network

    From Onions to Shallots: Rewarding Tor Relays with TEARS Rob Jansen1 , Andrew Miller2 , Paul.ford@yale.edu Abstract. The Tor anonymity network depends on volunteers to oper- ate relays, and might offer higher be deployed in the existing Tor network or operate alongside it. 1 Introduction Tor is the most popular

  9. Heat transfer and tear film dynamics over multiple blink cycles

    NASA Astrophysics Data System (ADS)

    Deng, Quan; Braun, R. J.; Driscoll, Tobin A.

    2014-07-01

    We consider model problems for the tear film over multiple blink cycles with heat transfer from the posterior side of the tear film. A nonlinear partial differential equation governs the film thickness on a moving domain in one space dimension and time. One end of the tear film moves in order to mimic blinking in the eye. The film thickness is coupled with the diffusion of heat from the posterior of the film, where the underlying cornea and aqueous humor are modeled as a rectangular domain. The domain of the tear film is located on one edge of the rectangle. The resulting problem is solved using the method of lines with a Chebyshev spectral method in space. Evaporation is included in the model, with end fluxes specified to compensate for the evaporation from the film. The numerical results reveal a similarity to quantitative in vivo observations of the film dynamics and measured ocular surface temperature. Periodicity in the film and temperature dynamics is explored with different flux conditions and end motions, and a transition between periodic and non-periodic solutions is analyzed.

  10. MACHINE LEARNING METHODS WITHOUT TEARS: A PRIMER FOR ECOLOGISTS

    E-print Network

    Poff, N. LeRoy

    MACHINE LEARNING METHODS WITHOUT TEARS: A PRIMER FOR ECOLOGISTS Julian D. Olden School of Aquatic modeling abstract Machine learning methods, a family of statistical techniques with origins in the field to other disciplines. One potential explanation for this lack of interest is that machine learning

  11. Biceps instability and Slap type II tear in overhead athletes.

    PubMed

    Osti, Leonardo; Soldati, Francesco; Cheli, Andrea; Pari, Carlotta; Massari, Leo; Maffulli, Nicola

    2012-10-01

    Type II lesions are common lesions encountered in overhead athletes with controversies arising in term of timing for treatment, surgical approach, rehabilitation and functional results. The aim of our study was to evaluate the outcomes of arthroscopic repair of type II SLAP tears in overhead athletes, focusing on the time elapsed from diagnosis and treatment, time needed to return to sport, rate of return to sport and to previous level of performance, providing an overview concerning evidence for the effectiveness of different surgical approaches to type II SLAP tears in overhead athletes. A internet search on peer reviewed Journal from 1990, first descriprion of this pathology, to 2012, have been conducted evaluating the outcomes for both isolated Slap II tear overhead athletes and those who presented associated lesions treated. The results have been analyzed according to the scale reported focusing on return to sport and level of activity. Apart from a single study, non prospective level I and II studies were detected. Return to play at the same level ranged form 22% to 94% with different range of technique utilized with the majority of the authors recommending the fixation of these lesions but biceps tenodesis can lead to higher satisfaction racte when directly compated to the anchor fixation. Associated pathologies such as partial or full tickness rotator cuff tear did not clearly affect the outcomes and complications rate. There is no consensus regarding timing and treatment for type II SLAP, especially in overhead athletes who need to regain a high level of performance. PMID:23738307

  12. Biceps instability and Slap type II tear in overhead athletes

    PubMed Central

    Osti, Leonardo; Soldati, Francesco; Cheli, Andrea; Pari, Carlotta; Massari, Leo; Maffulli, Nicola

    2012-01-01

    Summary Type II lesions are common lesions encountered in overhead athletes with controversies arising in term of timing for treatment, surgical approach, rehabilitation and functional results. The aim of our study was to evaluate the outcomes of arthroscopic repair of type II SLAP tears in overhead athletes, focusing on the time elapsed from diagnosis and treatment, time needed to return to sport, rate of return to sport and to previous level of performance, providing an overview concerning evidence for the effectiveness of different surgical approaches to type II SLAP tears in overhead athletes. A internet search on peer reviewed Journal from 1990, first descriprion of this pathology, to 2012, have been conducted evaluating the outcomes for both isolated Slap II tear overhead athletes and those who presented associated lesions treated. The results have been analyzed according to the scale reported focusing on return to sport and level of activity. Apart from a single study, non prospective level I and II studies were detected. Return to play at the same level ranged form 22% to 94% with different range of technique utilized with the majority of the authors recommending the fixation of these lesions but biceps tenodesis can lead to higher satisfaction racte when directly compated to the anchor fixation. Associated pathologies such as partial or full tickness rotator cuff tear did not clearly affect the outcomes and complications rate. There is no consensus regarding timing and treatment for type II SLAP, especially in overhead athletes who need to regain a high level of performance. PMID:23738307

  13. Understanding and preventing complications in repairing rotator cuff tears.

    PubMed

    Osti, Leonardo; Papalia, Rocco; Del Buono, Angelo; Denaro, Vincenzo; Maffulli, Nicola

    2012-01-01

    Repair of rotator cuff tears is a common procedure. Prior to approaching this surgery, it should be realized that each surgical step can lead to complications, including those related to positioning and anaesthesia. Stiffness, infection and failure of repair are the more frequent complications reported. PMID:21986055

  14. Treatment Options for Rotator Cuff Tears: A Guide for Adults

    MedlinePLUS

    ... and Plug-ins EHC Component EPC Project Topic Title Comparative Effectiveness of Nonoperative and Operative Treatments for Rotator Cuff Tears Full Reports Research Review Jul. 5, 2010 Appendixes Jul. 5, 2010 Related Products for this Topic Disposition of Comments Report ...

  15. Magnetic Reconnection: Recursive Current Sheet Collapse Triggered by “Ideal” Tearing

    NASA Astrophysics Data System (ADS)

    Tenerani, Anna; Velli, Marco; Rappazzo, Antonio Franco; Pucci, Fulvia

    2015-11-01

    We study, by means of MHD simulations, the onset and evolution of fast reconnection via the “ideal” tearing mode within a collapsing current sheet at high Lundquist numbers (S\\gg {10}4). We first confirm that as the collapse proceeds, fast reconnection is triggered well before a Sweet–Parker-type configuration can form: during the linear stage, plasmoids rapidly grow in a few Alfvén times when the predicted “ideal” tearing threshold S?1/3 is approached from above; after the linear phase of the initial instability, X-points collapse and reform nonlinearly. We show that these give rise to a hierarchy of tearing events repeating faster and faster on current sheets at ever smaller scales, corresponding to the triggering of “ideal” tearing at the renormalized Lundquist number. In resistive MHD, this process should end with the formation of sub-critical (S ? 104) Sweet–Parker sheets at microscopic scales. We present a simple model describing the nonlinear recursive evolution that explains the timescale of the disruption of the initial sheet.

  16. The PRISM Workwench: Database Schema Evolution Without Tears

    E-print Network

    Zaniolo, Carlo

    The PRISM Workwench: Database Schema Evolution Without Tears Carlo A. Curino #1 , Hyun J. Moon 2. In fact, PRISM exploits recent theoretical results on mapping composition, invertibility and query of schema mapping, mapping composition and invertibility, and query rewriting [3], [4], [5], [6]. This work

  17. Low back pain associated with lumbar disc herniation: role of moderately degenerative disc and annulus fibrous tears.

    PubMed

    Yang, Hao; Liu, Hui; Li, Zemin; Zhang, Kuibo; Wang, Jianru; Wang, Hua; Zheng, Zhaomin

    2015-01-01

    Lumbar disc herniation is one of the most common spinal degenerative disorders which may lead to low back pain (LBP) and radicular leg pain. However, it remains difficult to diagnose a degenerative herniated disc as the LBP generator in clinical practice. The purpose of this study is to explore the characteristic changes of a herniated disc causing LBP on MRI and to clarify the underlying role of inflammatory mediators and annulus fibrous (AF) tears in LBP generation associated with disc herniation. We prospectively collected intervertebral disc specimens and MRI from 57 single-segment disc herniation patients with radiculopathy. All subjects were grouped according to LBP occurrence or disc degeneration severity for the comparison of inflammatory mediators' expression and AF tears occurrence (High Intensity Zone, HIZ, on MRI). LBP incidence under circumstances of different degeneration severity with or without HIZ was further analyzed. Both LBP incidence and Inflammatory mediators expression in moderately degenerated group was higher than mildly and severely degenerative groups. HIZ incidence was higher in moderately and severely degenerated groups. LBP incidence in the patients with both moderately degenerated discs and HIZ was 86.7%, much higher than the rest of the patient population. In conclusion, the high expression of inflammatory mediators with AF tears causes LBP associated with disc herniation. Moderately degenerative disc with HIZ is MRI morphological change of herniated disc causing LBP, which can be applied to diagnose LBP. PMID:25932092

  18. Mechanoactive Scaffold Induces Tendon Remodeling and Expression of Fibrocartilage Markers

    PubMed Central

    Spalazzi, Jeffrey P.; Vyner, Moira C.; Jacobs, Matthew T.; Moffat, Kristen L.

    2008-01-01

    Biological fixation of soft tissue-based grafts for anterior cruciate ligament (ACL) reconstruction poses a major clinical challenge. The ACL integrates with subchondral bone through a fibrocartilage enthesis, which serves to minimize stress concentrations and enables load transfer between two distinct tissue types. Functional integration thus requires the reestablishment of this fibrocartilage interface on reconstructed ACL grafts. We designed and characterized a novel mechanoactive scaffold based on a composite of poly-?-hydroxyester nanofibers and sintered microspheres; we then used the scaffold to test the hypothesis that scaffold-induced compression of tendon grafts would result in matrix remodeling and the expression of fibrocartilage interface-related markers. Histology coupled with confocal microscopy and biochemical assays were used to evaluate the effects of scaffold-induced compression on tendon matrix collagen distribution, cellularity, proteoglycan content, and gene expression over a 2-week period. Scaffold contraction resulted in over 15% compression of the patellar tendon graft and upregulated the expression of fibrocartilage-related markers such as Type II collagen, aggrecan, and transforming growth factor-?3 (TGF-?3). Additionally, proteoglycan content was higher in the compressed tendon group after 1 day. The data suggest the potential of a mechanoactive scaffold to promote the formation of an anatomic fibrocartilage enthesis on tendon-based ACL reconstruction grafts. PMID:18512112

  19. Spontaneous Flexor Tendon Rupture Due to Atraumatic Chronic Carpal Instability

    PubMed Central

    Miranda, B. H.; Cerovac, S.

    2014-01-01

    Background?Spontaneous flexor tendon rupture is considered to be invariably associated with previous hand/wrist injury or systemic disease such as rheumatoid arthritis. Case Description?A 54-year-old man presented with a 4-month history of mild ulnar wrist pain and spontaneous left little finger flexion loss in the absence of distant/recent trauma and systemic arthropathy. Surgical exploration confirmed a zone IV left little finger flexor digitorum profundus (FDP5) attritional rupture (100%), ring finger flexor digitorum profundus (FDP4) attenuation (40%) and a disrupted lunotriquetral ligament and volar-ulnar wrist capsule. Volar subluxation of the narrowed carpal tunnel resulted in flexor tendon attrition against the hamate hook. A side-to-side tendon transfer was performed along with a lunotriquetral ligament repair and temporary Kirschner wire fixation. At 6 months the patient had full active, synchronous flexion of the ring and little fingers and reduced wrist pain. Literature Review?Traumatic flexor tendon ruptures have been reported following distal radius/hamate hook fractures, from carpal bone osteophytes, accessory carpal bones and intraosseous ganglia. Attritional ruptures caused by chronic, degenerative carpal pathology are less common. Clinical Relevance?This case highlights an unusual cause of flexor tendon rupture due to chronic carpal instability. PMID:25032080

  20. Arthroscopic biceps tendon tenodesis: the anchorage technical note.

    PubMed

    Castagna, A; Conti, M; Mouhsine, E; Bungaro, P; Garofalo, R

    2006-06-01

    Treatment of long head biceps (LHB) tendon pathology has become an area of renewed interest and debate among orthopaedic surgeons in recent years. The background of this manuscript is a description of biceps tenodesis which ensure continual dynamic action of the tendon which depresses the head and impedes lateral translation. A new technique has been developed in order to treat LHB tendon irreversible structural abnormalities associated with cuff rotator lesions. This technique entails the construction of a biological anchor between the LHB and supraspinatus and/or infraspinatus tendons according to arthroscopic findings. The rationale, although not supported by biomechanical studies is to obtain a triple, biomechanical effect. The first of these biomechanical effects which we try to promote through the procedure of transposition is the elimination of the deviation and oblique angle which occurs as the LHB completes its intra-articular course prior to reaching the bicipital groove. Furthermore, we have found this technique extremely useful in the presence of large ruptures of the rotator cuff with muscle retraction. The most common complication associated to this particular method, observed in less than 3%, is failed biological fixation which manifests as subsidence of the tenodesis and consequent descent of the tendon with evident aesthetic deformity. PMID:16374589

  1. Tendon-to-Bone Attachment: From Development to Maturity

    PubMed Central

    Zelzer, Elazar; Blitz, Einat; Killian, Megan L.; Thomopoulos, Stavros

    2014-01-01

    The attachment between tendon and bone occurs across a complex transitional tissue that minimizes stress concentrations and allows for load transfer between muscles and skeleton. This unique tissue cannot be reconstructed following injury, leading to high incidence of recurrent failure and stressing the need for new clinical approaches. This review describes the current understanding of the development and function of the attachment site between tendon and bone. The embryonic attachment unit, namely, the tip of the tendon and the bone eminence into which it is inserted, was recently shown to develop modularly from a unique population of Sox9- and Scx-positive cells, which are distinct from tendon fibroblasts and chondrocytes. The fate and differentiation of these cells is regulated by transforming growth factor beta and bone morphogenetic protein signaling, respectively. Muscle loads are then necessary for the tissue to mature and mineralize. Mineralization of the attachment unit, which occurs postnatally at most sites, is largely controlled by an Indian hedgehog/parathyroid hormone-related protein feedback loop. A number of fundamental questions regarding the development of this remarkable attachment system require further study. These relate to the signaling mechanism that facilitates the formation of an interface with a gradient of cellular and extracellular phenotypes, as well as to the interactions between tendon and bone at the point of attachment. PMID:24677726

  2. Cell therapies for tendons: old cell choice for modern innovation.

    PubMed

    Petrou, Ilias G; Grognuz, Anthony; Hirt-Burri, Nathalie; Raffoul, Wassim; Applegate, Lee Ann

    2014-01-01

    Although tissue engineering and cell therapies are becoming realistic approaches for medical therapeutics, it is likely that musculoskeletal applications will be among the first to benefit on a large scale. Cell sources for tissue engineering and cell therapies for tendon pathologies are reviewed with an emphasis on small defect tendon injuries as seen in the hand which could adapt well to injectable cell administration. Specifically, cell sources including tenocytes, tendon sheath fibroblasts, bone marrow or adipose-derived stem cells, amniotic cells, placenta cells and platelet-derivatives have been proposed to enhance tendon regeneration. The associated advantages and disadvantages for these different strategies will be discussed and evolving regulatory requirements for cellular therapies will also be addressed. Human progenitor tenocytes, along with their clinical cell banking potential, will be presented as an alternative cell source solution. Similar cell banking techniques have already been described with other progenitor cell types in the 1950's for vaccine production, and these "old" cell types incite potentially interesting therapeutic options that could be improved with modern innovation for tendon regeneration and repair. PMID:25102358

  3. Intratendinous Tophaceous Gout Imitating Patellar Tendonitis in an Athletic Man

    PubMed Central

    Gililland, Jeremy M.; Webber, Nicholas P.; Jones, Kevin B.; Randall, R. Lor; Aoki, Stephen K.

    2013-01-01

    Patellar tendon-related pain is common in the athletic patient. When it occurs in skeletally mature patients participating in running, jumping, or kicking sports, the diagnosis of jumper’s knee patellar tendonitis is usually made. If patellar tendon pain is associated with a mass, the differential diagnosis should be broadened to include crystalline arthropathy. This article presents a case of a highly athletic 45-year-old man with a history of gout, anterior knee pain, and an enlarging mass in the region of the patellar tendon. Conservative management failed, and an excisional biopsy found it to be an intra-tendinous gouty tophus. To our knowledge, only 1 report exists documenting a patellar tendon mass secondary to gout, and no case report exists documenting this problem in an athlete. The interplay between athletics and gout has not been well described. Despite the long-term protective nature of fitness, transient elevations in uric acid associated with athletic endeavors may contribute acutely to manifestations of gout in some athletes. Resultant intra- or extra-articular pathology may present as, and easily be mistaken for, a sports-related injury. Without appropriate medical management, tophaceous deposition may continue to occur and treatment of the resultant mass may require surgical intervention. PMID:21410111

  4. Tendon Mechanobiology: Current Knowledge and Future Research Opportunities

    PubMed Central

    Lavagnino, Michael; Wall, Michelle E.; Little, Dianne; Banes, Albert J.; Guilak, Farshid; Arnoczky, Steven P.

    2015-01-01

    Tendons mainly function as load-bearing tissues in the muscloskeletal system, transmitting loads from muscle to bone. Tendons are dynamic structures that respond to the magnitude, direction, frequency, and duration of physiologic as well as pathologic mechanical loads via complex interactions between cellular pathways and the highly specialized extracellular matrix. This paper reviews the evolution and current knowledge of mechanobiology in tendon development, homeostasis, disease, and repair. In addition, we review several novel mechanotransduction pathways that have been identified recently in other tissues and cell types, providing potential research opportunities in the field of tendon mechanobiology. We also highlight current methods, models, and technologies being used in a wide variety of mechanobiology research that could be investigated in the context of their potential applicability for answering some of the fundamental unanswered questions in this field. The article concludes with a review of the major questions and future goals discussed during the recent ORS/ISMMS New Frontiers in Tendon Research Conference held September 10–11, 2014 in New York City. PMID:25763779

  5. Intense focused ultrasound stimulation of the rotator cuff: evaluation of the source of pain in rotator cuff tears and tendinopathy.

    PubMed

    Gellhorn, Alfred C; Gillenwater, Cody; Mourad, Pierre D

    2015-09-01

    The objective of this preliminary study was to evaluate the ability of individual 0.1-s long pulses of intense focused ultrasound (iFU) emitted with a carrier frequency of 2 MHz to evoke diagnostic sensations when applied to patients whose shoulders have rotator cuff tears or tendinopathy. Patients were adults with painful shoulders and clinical and imaging findings consistent with rotator cuff disease. iFU stimulation of the shoulder was performed using B-mode ultrasound coupled with a focused ultrasound transducer that allowed image-guided delivery of precisely localized pulses of energy to different anatomic areas around the rotator cuff. The main outcome measure was iFU spatial average-temporal average intensity (I_SATA), and location required to elicit sensation. In control patients, iFU produced no sensation throughout the range of stimulation intensities (?2000 W/cm(2) I_SATA). In patients with rotator cuff disease, iFU was able to induce sensation in the tendons of the rotator cuff, the subacromial bursa, and the subchondral bone in patients with chronic shoulder pain and rotator cuff disease, with an average ± standard deviation intensity equaling 680 ± 281 W/cm(2) I_SATA. This result suggests a primary role for these tissues in the pathogenesis of shoulder pain related to rotator cuff tendinopathy. PMID:26058842

  6. Acute Multiple Flexor Tendon Injury and Carpal Tunnel Syndrome After Open Distal Radius Fracture.

    PubMed

    Erickson, John; Culp, Brian; Kayiaros, Stephen; Monica, James

    2015-11-01

    Although the rupture of extensor tendons after distal radius fractures is well described, acute flexor tendon ruptures are much less common. We report a case of acute rupture of the flexor pollicis longus and flexor carpi radialis tendons with acute carpal tunnel syndrome after a Gustilo-Anderson type II open distal radius fracture. We reviewed the literature to identify risk factors for tendon rupture and the development of carpal tunnel syndrome. PMID:26566562

  7. A single-center study evaluating the effect of the controlled adverse environment (CAESM) model on tear film stability

    PubMed Central

    Abelson, Richard; Lane, Keith J; Rodriguez, John; Johnston, Patrick; Angjeli, Endri; Ousler, George; Montgomery, Douglas

    2012-01-01

    Purpose To investigate use of an improved ocular tear film analysis protocol (OPI 2.0) in the Controlled Adverse Environment (CAESM) model of dry eye disease, and to examine the utility of new metrics in the identification of subpopulations of dry eye patients. Methods Thirty-three dry eye subjects completed a single-center, single-visit, pilot CAE study. The primary endpoint was mean break-up area (MBA) as assessed by the OPI 2.0 system. Secondary endpoints included corneal fluorescein staining, tear film break-up time, and OPI 2.0 system measurements. Subjects were also asked to rate their ocular discomfort throughout the CAE. Dry eye endpoints were measured at baseline, immediately following a 90-minute CAE exposure, and again 30 minutes after exposure. Results The post-CAE measurements of MBA showed a statistically significant decrease from the baseline measurements. The decrease was relatively specific to those patients with moderate to severe dry eye, as measured by baseline MBA. Secondary endpoints including palpebral fissure size, corneal staining, and redness, also showed significant changes when pre- and post-CAE measurements were compared. A correlation analysis identified specific associations between MBA, blink rate, and palpebral fissure size. Comparison of MBA responses allowed us to identify subpopulations of subjects who exhibited different compensatory mechanisms in response to CAE challenge. Of note, none of the measures of tear film break-up time showed statistically significant changes or correlations in pre-, versus post-CAE measures. Conclusion This pilot study confirms that the tear film metric MBA can detect changes in the ocular surface induced by a CAE, and that these changes are correlated with other, established measures of dry eye disease. The observed decrease in MBA following CAE exposure demonstrates that compensatory mechanisms are initiated during the CAE exposure, and that this compensation may provide the means to identify and characterize clinically relevant subpopulations of dry eye patients. PMID:23185114

  8. Tears Rendering in Extreme Expression by Using SPH Method and Gravity Parameters

    NASA Astrophysics Data System (ADS)

    Rahim, Mohd Shafry Mohd; Rad, Abdolvahab Ehsani; Rehman, Amjad; Altameem, Ayman

    2014-06-01

    The simulation of fluid generation and the Smooth Particle Hydrodynamic (SPH) method has been discussed as an explanation for extreme expression, followed by tears simulation which includes creating tears using SPH and tears effect rendering. Furthermore, the testing and the evaluation for creating tears simulation with different effects and cases were applied. Accordingly, this paper explains how to control the crying with the facial animation expressions which are used to simulate the extreme expressions. Additionally, the results of various aspects of this study and the different kinds of crying were simulated and explained. Finally, the measurements of frame rates for different parts of tears simulation by using Fraps software have been explored.

  9. Giant cell tumour of tendon sheath (localised nodular tenosynovitis): clinicopathological features of 71 cases

    PubMed Central

    Monaghan, H; Salter, D; Al-Nafussi, A

    2001-01-01

    Aims/Background—Giant cell tumour of the tendon sheath (GCTTS) is regarded as the most common neoplasm of the hand that can recur after excision. The objective of this study was to review a series of cases in our department and to determine any clinical or pathological features that might predict the likelihood of recurrence. Methods—Clinical data, obtained from pathology request forms and in patient notes, along with the gross and microscopic appearances of 71 cases of GCTTS were evaluated. Results—Clinical features and pathological features identified were similar to those of previous studies. In comparison with previous studies a higher mitotic count (range, 1–21 mitoses/10 high power fields (HPF); mean, 5/10 HPF) was noted in all cases, irrespective of recurrence and numerous apoptotic bodies (up to 30/10 HPF), mainly formed from osteoclast-like giant cells, were present. Conclusions—GCTTS is a relatively rare soft tissue tumour of uncertain histiogenesis. Mitotic and apoptotic figures are a common feature and do not indicate clinical behaviour. Complete local excision is the treatment of choice. Key Words: giant cell tumour tendon sheath • apoptosis • osteoclasts PMID:11328844

  10. Functional reconstruction of Achilles tendon defects combined with overlaying skin defects using a free tensor fasciae latae flap.

    PubMed

    Dabernig, J; Shilov, B; Schumacher, O; Lenz, C; Dabernig, W; Schaff, J

    2006-01-01

    We present our experience in functional reconstruction of the Achilles tendon with large tissue defects following after trauma and infection. To cover the skin defect and to reconstruct the Achilles tendon we used the free tensor fasciae latae (TFL) flap. From 1997 to 2003 six males, ranging from 22 to 71 (average 38.6) years, underwent this reconstructive procedure. All of them had sustained a trauma with following loss of the tendon and of the overlying tissue. After initial debridements the reconstruction with a tensor fascia latae free flap was performed. To achieve a strong distal fascia lata attachment to the calcaneal bone, we developed a special method of fixation. After vertical osteotomy in the calcaneus the distal part of the fascia flap was introduced between the bone segments, which were fixed together with a spongiosa screw. For functional outcome, it was important to fix the foot in a 90 degrees position with tension on the vascularised fascia lata. The range of motion of the ankle of the reconstructed foot showed 93.7% in comparison to the normal foot. No flap failure occurred in any of the six patients. Simultaneous soft-tissue and function restoration of the foot with TFL free flap is in our opinion an optimal one-stage reconstructive procedure. PMID:16703858

  11. Patellar Tendon Reconstruction in Total Knee Arthroplasty: A New Technique.

    PubMed

    Rajgopal, Ashok; Vasdev, Attique; Dahiya, Vivek

    2015-12-01

    Patellar tendon disruption is one of the most dreaded complications following total knee arthroplasty (TKA) impacting both implant function and implant longevity. To overcome the concerns regarding allografts and improve outcomes with augmentation techniques, we describe a technique, which we have successfully used over the past 4 years with good results. Seven patients underwent reconstruction for patellar tendon disruption using our technique from a cohort of eight patients. Extensor lag improved from a mean of 40 degrees to less than 5 degrees postoperatively. Range of motion improved from a mean of 105 degrees to 115 degrees of flexion. There was improvement in Knee Society Functional Score from a preoperative mean of 30 to 75 points. The Knee Society Pain Score, however, did not show much improvement. We believe our technique to be a solution to the difficult problem of patellar tendon ruptures after TKA and we continue to perform this procedure. PMID:25251879

  12. Tendon grafts: their natural history, biology and future development.

    PubMed

    Wong, R; Alam, N; McGrouther, A D; Wong, J K F

    2015-09-01

    The use of tendon grafts has diminished as regimes of primary repairs and rehabilitation have improved, but they remain important in secondary reconstruction. Relatively little is known about the cellular biology of grafts, and the general perception is that they have little biological activity. The reality is that there is a wealth of cellular and molecular changes occurring with the process of engraftment that affect the quality of the repair. This review highlights the historical perspectives and modern concepts of graft take, reviews the different attachment techniques and revisits the biology of pseudosheath formation. In addition, we discuss some of the future directions in tendon reconstruction by grafting, which include surface modification, vascularized tendon transfer, allografts, biomaterials and cell-based therapies. PMID:26264585

  13. HUBBLE WATCHES STAR TEAR APART ITS NEIGHBORHOOD

    NASA Technical Reports Server (NTRS)

    2002-01-01

    NASA's Hubble Space Telescope has snapped a view of a stellar demolition zone in our Milky Way Galaxy: a massive star, nearing the end of its life, tearing apart the shell of surrounding material it blew off 250,000 years ago with its strong stellar wind. The shell of material, dubbed the Crescent Nebula (NGC 6888), surrounds the 'hefty,' aging star WR 136, an extremely rare and short-lived class of super-hot star called a Wolf-Rayet. Hubble's multicolored picture reveals with unprecedented clarity that the shell of matter is a network of filaments and dense knots, all enshrouded in a thin 'skin' of gas [seen in blue]. The whole structure looks like oatmeal trapped inside a balloon. The skin is glowing because it is being blasted by ultraviolet light from WR 136. Hubble's view covers a small region at the northeast tip of the structure, which is roughly three light-years across. A picture taken by a ground-based telescope [lower right] shows almost the entire nebula. The whole structure is about 16 light-years wide and 25 light-years long. The bright dot near the center of NGC 6888 is WR 136. The white outline in the upper left-hand corner represents Hubble's view. Hubble's sharp vision is allowing scientists to probe the intricate details of this complex system, which is crucial to understanding the life cycle of stars and their impact on the evolution of our galaxy. The results of this study appear in the June issue of the Astronomical Journal. WR 136 created this web of luminous material during the late stages of its life. As a bloated, red super-giant, WR 136 gently puffed away some of its bulk, which settled around it. When the star passed from a super-giant to a Wolf-Rayet, it developed a fierce stellar wind - a stream of charged particles released from its surface - and began expelling mass at a furious rate. The star began ejecting material at a speed of 3.8 million mph (6.1 million kilometers per hour), losing matter equal to that of our Sun's every 10,000 years. Then the stellar wind collided with the material around the star and swept it up into a thin shell. That shell broke apart into the network of bright clumps seen in the image. The present-day strong wind of the Wolf-Rayet star has only now caught up with the outer edge of the shell, and is stripping away matter as it flows past [the tongue-shaped material in the upper right of the Hubble image]. The stellar wind continues moving outside the shell, slamming into more material and creating a shock wave. This powerful force produces an extremely hot, glowing skin [seen in blue], which envelops the bright nebula. A shock wave is analogous to the sonic boom produced by a jet plane that exceeds the speed of sound; in a cosmic setting, this boom is seen rather than heard. The outer material is too thin to see in the image until the shock wave hits it. The cosmic collision and subsequent shock wave implies that a large amount of matter resides outside the visible shell. The discovery of this material may explain the discrepancy between the mass of the entire shell (four solar masses) and the amount of matter the star lost when it was a red super-giant (15 solar masses). The nebula's short-term fate is less spectacular. As the stellar wind muscles past the clumps of material, the pressure around them drops. A decrease in pressure means that the clumps expand, leading to a steady decline in brightness and fading perhaps to invisibility. Later, the shell may be compressed and begin glowing again, this time as the powerful blast wave of the Wolf-Rayet star completely destroys itself in a powerful supernova explosion. The nebula resides in the constellation Cygnus, 4,700 light-years from Earth. If the nebula were visible to the naked eye, it would appear in the sky as an ellipse one-quarter the size of the full moon. The observations were taken in June 1995 with the Wide Field and Planetary Camera 2. Scientists selected the colors in this composite image to correspond with the ionization (the process of stripping electrons from atoms) state of the gases, with blue r

  14. Effect of Heating on the Suppression of Tearing Modes in Tokamaks

    SciTech Connect

    Classen, I. G. J.; Westerhof, E.; Donne, A. J. H.; Jaspers, R. J. E.; Pol, M. J. van de; Spakman, G. W.; Domier, C. W.; Luhmann, N. C. Jr.; Park, H. K.; Jakubowski, M. W.

    2007-01-19

    The suppression of (neoclassical) tearing modes is of great importance for the success of future fusion reactors like ITER. Electron cyclotron waves can suppress islands, both by driving noninductive current in the island region and by heating the island, causing a perturbation to the Ohmic plasma current. This Letter reports on experiments on the TEXTOR tokamak, investigating the effect of heating, which is usually neglected. The unique set of tools available on TEXTOR, notably the dynamic ergodic divertor to create islands with a fully known driving term, and the electron cyclotron emission imaging diagnostic to provide detailed 2D electron temperature information, enables a detailed study of the suppression process and a comparison with theory.

  15. THE OCULAR SURFACE / OCTOBER 2007, VOL. 5, NO. 4 / www.theocularsurface.com280 Tear Glucose Analysis for the Noninvasive

    E-print Network

    Asher, Sanford A.

    to the noninvasive monitoring of blood glucose concentration is to monitor glucose concentra- tions in tear fluid. While several methods for sensing glucose in tear fluid have been proposed, controversy remains as to the precise concentrations of tear glucose in normal and diabetic subjects and as to whether tear fluid

  16. ProTec Tear-Offs: A Preliminary Assessment

    SciTech Connect

    Peeler, D

    2005-09-01

    The Savannah River National Laboratory (SRNL) has conducted a series of ''scoping'' tests (referred to as Phase 1) to assess the potential use of a Mylar{reg_sign} tear-off system as a primary or secondary protective barrier to minimize acid etching (''frosting''), accidental scratching, and/or radiation damage for shielded cells windows. Conceptually, thin, multi-layered sheets of Mylar (referred to as a ''tear-off'' system) could be directly applied to the Lexan{reg_sign} sheet or glovebox/hood sash window to serve as a secondary (or primary) barrier. Upon degradation of visual clarity due to accidental scratching, spills/splatters, and/or radiation damage, the outer layer (or sheet) of Mylar could be removed ''refreshing'' or restoring the view. Due to the multi-layer aspect, the remaining Mylar layers would provide continued protection for the window from potential reoccurrences (which could be immediate or after some extended time period). Although the concept of using a tear-off system as a protective barrier was conceptually enticing, potential technical issues were identified and addressed as part of this Phase 1 feasibility study. These included resistance to: (1) acid(s) (concentrated (28.9 M) HF, concentrated (15.9M) HNO{sub 3}, 6M HCl, and 0.6M H{sub 3}BO{sub 3}), (2) base (a simulated sludge with pH of 12.9), (3) gamma radiation (cumulative dose of {approx}200,000 rad), and (4) scratch resistance (simulating accidental scratching with the manipulators). Not only can these four factors play a significant role in determining the visual clarity of the integrated system, they can also contribute to the mechanical integrity issues which could dictate the ability to remove the outer layer when visual clarity has degraded. The results of the Phase 1 study clearly indicate that the Mylar tear-off concept (as a primary or secondary protective barrier) is a potential technical solution to prevent or retard excessive damage that would result from acid etching, base damage (as a result of a sludge spill or splatter), gamma radiation damage, and/or accidental scratching (due to manipulator/tool contact). The short term tests performed in this task showed that Mylar tear-offs can withstand the chemical and physical abuses expected in off-normal shielded cells operations. The ''tear-offs'' not only provide some measure of acid resistance, as reflected by the lack of visual degradation after being exposed to four acids, but also act as a protective barrier to accidental contact with the manipulators and/or tools. The conceptual ''erasing'' of scratches or marks was demonstrated in the shielded cell mock-up facility through the removal, with manipulators, of the outer layer tear-off. The successful removal of the outer layer tear-off with the manipulator, using tabs not specifically designed for remote operations, demonstrates that the system is ''manipulator-friendly'' and could be implemented in the shielded cells. The ability to remove the outer layer tear-off not only regains visual clarity but also reduces waste disposal volumes (i.e., disposal of a thin sheet of Mylar which is ''collapsible'' versus the bulk disposal of a rigid Lexan sheet or glovebox/sash window) which is more cost effective. The ''tear-off'' system could also reduce the number of cell entries needed to replace the Lexan sheet and increase the time interval between glovebox/sash window change outs which can be costly and time consuming. Although the primary focus of this report addresses the application of the Mylar tear-offs on shielded cells windows, the concept is also potentially applicable to glovebox and hood sash windows. In fact, the tear-off concept is potentially applicable to any system where visual clarity is compromised given the environmental conditions of the test. In addition, the tear-offs could be applied to walls or shelves where a protective barrier would reduce deterioration or discoloration. This concept is referred to as the ProTec{trademark} tear-off system as its primary intent is to protect windows or surfaces.

  17. Biomechanical risk factors and flexor tendon frictional work in the cadaveric carpal tunnel.

    PubMed

    Kociolek, Aaron M; Tat, Jimmy; Keir, Peter J

    2015-02-01

    Pathological changes in carpal tunnel syndrome patients include fibrosis and thickening of the subsynovial connective tissue (SSCT) adjacent to the flexor tendons in the carpal tunnel. These clinical findings suggest an etiology of excessive shear-strain force between the tendon and SSCT, underscoring the need to assess tendon gliding characteristics representative of repetitive and forceful work. A mechanical actuator moved the middle finger flexor digitorum superficialis tendon proximally and distally in eight fresh frozen cadaver arms. Eighteen experimental conditions tested the effects of three well-established biomechanical predictors of injury, including a combination of two wrist postures (0° and 30° flexion), three tendon velocities (50, 100, 150mm/sec), and three forces (10, 20, 40N). Tendon gliding resistance was determined with two light-weight load cells, and integrated over tendon displacement to represent tendon frictional work. During proximal tendon displacement, frictional work increased with tendon velocity (58.0% from 50-150mm/sec). There was a significant interaction between wrist posture and tendon force. In wrist flexion, frictional work increased 93.0% between tendon forces of 10 and 40N. In the neutral wrist posture, frictional work only increased 33.5% (from 10-40N). During distal tendon displacement, there was a similar multiplicative interaction on tendon frictional work. Concurrent exposure to multiple biomechanical work factors markedly increased tendon frictional work, thus providing a plausible link to the pathogenesis of work-related carpal tunnel syndrome. Additionally, our study provides the conceptual basis to evaluate injury risk, including the multiplicative repercussions of combined physical exposures. PMID:25553671

  18. Predicting Rotator Cuff Tears Using Data Mining and Bayesian Likelihood Ratios

    PubMed Central

    Lu, Hsueh-Yi; Huang, Chen-Yuan; Su, Chwen-Tzeng; Lin, Chen-Chiang

    2014-01-01

    Objectives Rotator cuff tear is a common cause of shoulder diseases. Correct diagnosis of rotator cuff tears can save patients from further invasive, costly and painful tests. This study used predictive data mining and Bayesian theory to improve the accuracy of diagnosing rotator cuff tears by clinical examination alone. Methods In this retrospective study, 169 patients who had a preliminary diagnosis of rotator cuff tear on the basis of clinical evaluation followed by confirmatory MRI between 2007 and 2011 were identified. MRI was used as a reference standard to classify rotator cuff tears. The predictor variable was the clinical assessment results, which consisted of 16 attributes. This study employed 2 data mining methods (ANN and the decision tree) and a statistical method (logistic regression) to classify the rotator cuff diagnosis into “tear” and “no tear” groups. Likelihood ratio and Bayesian theory were applied to estimate the probability of rotator cuff tears based on the results of the prediction models. Results Our proposed data mining procedures outperformed the classic statistical method. The correction rate, sensitivity, specificity and area under the ROC curve of predicting a rotator cuff tear were statistical better in the ANN and decision tree models compared to logistic regression. Based on likelihood ratios derived from our prediction models, Fagan's nomogram could be constructed to assess the probability of a patient who has a rotator cuff tear using a pretest probability and a prediction result (tear or no tear). Conclusions Our predictive data mining models, combined with likelihood ratios and Bayesian theory, appear to be good tools to classify rotator cuff tears as well as determine the probability of the presence of the disease to enhance diagnostic decision making for rotator cuff tears. PMID:24733553

  19. Biologically based strategies to augment rotator cuff tears

    PubMed Central

    Schaer, M.; Schober, M.; Berger, S.; Boileau, P.; Zumstein, M. A.

    2012-01-01

    Lesions of the rotator cuff (RC) are among the most frequent tendon injuries. In spite of the developments in both open and arthroscopic surgery, RC repair still very often fails. In order to reduce the failure rate after surgery, several experimental in vitro and in vivo therapy methods have been developed for biological improvement of the reinsertion. This article provides an overview of the current evidence for augmentation of RC reconstruction with growth factors. Furthermore, potential future therapeutic approaches are discussed. We performed a comprehensive search of the PubMed database using various combinations of the keywords “tendon,” “rotator cuff,” “augmentation,” “growth factor,” “platelet-rich fibrin,” and “platelet-rich plasma” for publications up to 2011. Given the linguistic capabilities of the research team, we considered publications in English, German, French, and Spanish. We excluded literature reviews, case reports, and letters to the editor. PMID:22787334

  20. Ratios of cross-sectional areas of muscles and their tendons in a healthy human forearm.

    PubMed Central

    Cutts, A; Alexander, R M; Ker, R F

    1991-01-01

    The muscles and tendons in the forearm and hand of a young man, amputated after an accident, have been weighed and measured. The physiological cross-sectional areas of those muscles that had long tendons were 35 +/- 9 (mean and standard deviation) times the cross-sectional areas of the tendons. The mean is very close to the optimum calculated from the theory of Ker, Alexander & Bennett (1988). It implies that the tendons experience stresses of about 11 MPa and strains of about 1.3%, when the muscles exert their maximum isometric forces. Very much larger forces would be needed to break the tendons. PMID:1917668

  1. Missed Medial Malleolar Fracture Associated With Achilles Tendon Rupture: A Case Report and Literature Review.

    PubMed

    Nakajima, Koji; Taketomi, Shuji; Inui, Hiroshi; Nakamura, Kensuke; Sanada, Takaki; Tanaka, Sakae

    2016-01-01

    A 45-year-old man sustained an Achilles tendon rupture while playing futsal. A concomitant medial malleolar fracture was not diagnosed until the patient underwent an operation for Achilles tendon repair. A routine postoperative radiograph showed a minimally displaced medial malleolar fracture. Conservative treatment was chosen for the fracture. The function of the Achilles tendon recovered well, and the fracture was united. A medial malleolar fracture can be missed when an Achilles tendon rupture occurs simultaneously. Thus, surgeons should consider the possibility of medial malleolar fracture associated with an Achilles tendon rupture. PMID:25441273

  2. Experimental studies in chickens on the initial nutrition of tendon grafts.

    PubMed

    Manske, P R; Lesker, P A; Bridwell, K

    1979-11-01

    A study of nutrition of various tendon graft preparations in adult chickens (up to 2 weeks after grafting), using tritiated proline and a trichloracetic acid extraction technique which separated the free and metabolized amino acid fractions, suggests that diffusion of nutrients is an important process in the initial nutrition of tendon grafts, that tendon grafts are metabolically active and viable structures, that adhesions which are frequently associated with tendon grafts do not appear to be essential to the nutrition of grafts, and that tendon grafts within fibrous pseudosheaths are nourished as effectively as grafts within synovial sheaths. PMID:512314

  3. [Questions concerning two-stage reconstruction of injured flexor tendons. III. Ultrastructure of the tenosynovium in the pseudo-tendon sheath created by using a silicone rod].

    PubMed

    Salamon, A; Bíró, V; Vámhidy, L; Trombitás, K; Józsa, L

    1993-01-01

    Authors have investigated the ultrastructure of the pseudo tendon sheath, formed with silicon rod and man. They have observed a superficial structure, resembling the normal tendon sheath in scanning electron microscopic examination. With transmission electron microscopy phagocyte "A" type and secretion "B" type synovial cells were found. Authors state that the newly formed tenosynovium has an important role in the nutrition of the tendon graft and the prevention of adhesions. PMID:8136879

  4. Experimental flexor tendon healing without adhesion formation--a new concept of tendon nutrition and intrinsic healing mechanisms. A preliminary report.

    PubMed

    Lundborg, G

    1976-10-01

    An experimental model is presented enabling an analysis of the healing process of completely cut and re-sutured free segments of rabbit flexor tendons, kept avascular in a synovial milieu and completely isolated from adhesion formation. Under these conditions the cut tendons heal within a few weeks. It can be shown that this healing process is a result of intrinsic tendon cell activity only. PMID:976821

  5. PROTEC TM TEAR-OFFS: RESULTS OF LONG TERM TESTING

    SciTech Connect

    Peeler, D

    2008-07-24

    The Savannah River National Laboratory (SRNL) has completed a series of tests (Phases 1 and 2) to assess the potential use of a Mylar{reg_sign} tear-off system as a primary or secondary protective barrier to minimize acid etching ('frosting'), accidental scratching, and/or radiation damage for shielded cells, glovebox, and/or chemical hood windows. Conceptually, thin, multi-layered sheets of Mylar (referred to throughout this report as the ProTec{trademark} tear-off system) can be directly applied to the shielded cell, glovebox, or hood sash window to serve as a secondary (or primary) barrier. Upon degradation of visual clarity due to accidental scratching, spills/splatters, and/or radiation damage, the outer layer (or sheet) of Mylar could be removed refreshing or restoring the view. Due to the multilayer aspect, the remaining Mylar layers would provide continued protection for the window from potential reoccurrences. Although the concept of using a tear-off system as a protective barrier is conceptually enticing, potential technical issues were identified and addressed as part of this phased study to support implementation of this type of system in the Defense Waste Processing Facility (DWPF). Specific test conditions of interest to the DWPF included the performance of the tear-off system exposed to or under the following conditions: (1) acid(s) (concentrated (28.9 M) HF, concentrated (15.9M) HNO{sub 3}, 6M HCl, and 0.6M H{sub 3}BO{sub 3}); (2) base (based on handling of radioactive sludges with pH of {approx}12-13); (3) gamma radiation (due to radioactive sources or materials being used in the analytical cells); (4) scratch resistance (simulating accidental scratching with the manipulators); and (5) in-situ testing (sample coupons exposed to actual field conditions in DWPF). The results of the Phase 1 study indicated that the ProTec tear-off concept (as a primary or secondary protective barrier) is a potential technical solution to prevent or retard excessive damage that would result from acid etching, base damage (as a result of a sludge spill or splatter), gamma radiation damage, and/or accidental scratching (due to manipulator/tool contact). Although identified as a potential solution, the Phase 1 testing was relatively short-term with exposure times up to 1-2 months for the acid and gamma radiation tests. Phase 2 testing included longer exposure times for the acid resistance (up to 456 days) and gamma radiation exposure (700 days with a cumulative gamma dose of {approx}3.1 x 10{sup 5} rad) assessments. The tear-off system continued to perform well in these longer-term acid resistance testing and gamma exposure conditions. Complete removal of the tear-offs after these long-term exposure times indicate that not only could visual clarity be restored but the mechanical integrity could be retained. The results also provided insight into the ability of the ProTec tear-off system to withstand the chemical and physical abuses expected in off-normal shielded cells operations. The conceptual erasing of scratches or marks by excessive manipulator abuse was demonstrated in the SRNL Shielded Cells mock-up facility through the removal of the outer layer tear-off with manipulators. In addition, the Phase 2 testing included an in-situ assessment of a prototype tear-off system in the DWPF Sampling Cells where the system was exposed to actual field conditions including radioactive sources, acidic and basic environments, dusting, and chemical cleaning solutions over a 5-6 month period. DWPF personnel were extremely satisfied with the performance (including the successful removal of 3 layers with manipulators) of the ProTec tear-off system under actual field conditions. The successful removal of the outer layer tear-offs with the manipulator, using tabs not specifically designed for remote operations, demonstrates that the system is 'manipulator-friendly' and could be implemented in a remote environment. The ability to remove the outer layer tear-off not only regains visual clarity but also reduces waste disposal volumes (i.e., dispo

  6. Verification of gyrokinetic particle simulation of current-driven instability in fusion plasmas. II. Resistive tearing mode

    SciTech Connect

    Liu, Dongjian; Zhang, Wenlu; McClenaghan, Joseph; Wang, Jiaqi; Lin, Zhihong

    2014-12-15

    Global gyrokinetic particle simulation of resistive tearing modes has been developed and verified in the gyrokinetic toroidal code (GTC). GTC linear simulations in the fluid limit of the kink-tearing and resistive tearing modes in the cylindrical geometry agree well with the resistive magnetohydrodynamic eigenvalue and initial value codes. Ion kinetic effects are found to reduce the radial width of the tearing modes. GTC simulations of the resistive tearing modes in the toroidal geometry find that the toroidicity reduces the growth rates.

  7. Verification of gyrokinetic particle simulation of current-driven instability in fusion plasmas. II. Resistive tearing mode

    NASA Astrophysics Data System (ADS)

    Liu, Dongjian; Zhang, Wenlu; McClenaghan, Joseph; Wang, Jiaqi; Lin, Zhihong

    2014-12-01

    Global gyrokinetic particle simulation of resistive tearing modes has been developed and verified in the gyrokinetic toroidal code (GTC). GTC linear simulations in the fluid limit of the kink-tearing and resistive tearing modes in the cylindrical geometry agree well with the resistive magnetohydrodynamic eigenvalue and initial value codes. Ion kinetic effects are found to reduce the radial width of the tearing modes. GTC simulations of the resistive tearing modes in the toroidal geometry find that the toroidicity reduces the growth rates.

  8. Ultrasound characteristics of the patellar and quadriceps tendons among young elite athletes.

    PubMed

    Visnes, H; Tegnander, A; Bahr, R

    2015-04-01

    Tendons adapt in response to sports-specific loading, but sometimes develop tendinopathy. If the presence of ultrasound changes like hypoechoic areas and neovascularization in asymptomatic tendons precede (and predict) future tendon problems is unknown. The aim of this prospective cohort study was to investigate the relationship between the development of ultrasound changes in the patellar and quadriceps tendons and symptoms of jumper's knee, as well to examine the medium-term effects of intensive training on tendon thickness among adolescent athletes. Elite junior volleyball athletes were followed with semi-annual ultrasound and clinical examinations (average follow-up: 1.7 years). Of the 141 asymptomatic athletes included, 22 athletes (35 patellar tendons) developed jumper's knee. In a multivariate logistic regression analysis, a baseline finding of a hypoechoic tendon area (odds ratio 3.3, 95% confidence interval 1.1 to 9.2) increased the risk of developing symptoms of jumper's knee. Patellar tendon thickness among healthy athletes did not change (Wilk's lambda, P?=?0.07) while quadriceps tendon thickness increased (P?=?0.001). In conclusion, ultrasound changes at baseline were risk factors for developing symptoms of jumper's knee. Also, among healthy athletes, we observed a 7-11% increase in quadriceps tendon thickness, while there was no increase in patellar tendon thickness. PMID:24612006

  9. Histopathological and biomechanical evaluation of tenocyte seeded allografts on rat Achilles tendon regeneration.

    PubMed

    Güngörmü?, Cans?n; Kolankaya, Dürdane; Aydin, Erkin

    2015-05-01

    Tendon injuries in humans as well as in animals' veterinary medicine are problematic because tendon has poor regenerative capacity and complete regeneration of the ruptured tendon is never achieved. In the last decade there has been an increasing need of treatment methods with different approaches. The aim of the current study was to improve the regeneration process of rat Achilles tendon with tenocyte seeded decellularized tendon matrices. For this purpose, Achilles tendons were harvested, decellularized and seeded as a mixture of three consecutive passages of tenocytes at a density of 1 × 10(6) cells/ml. Specifically, cells with different passage numbers were compared with respect to growth characteristics, cellular senescence and collagen/tenocyte marker production before seeding process. The viability of reseeded tendon constructs was followed postoperatively up to 6 months in rat Achilles tendon by histopathological and biomechanical analysis. Our results suggests that tenocyte seeded decellularized tendon matrix can significantly improve the histological and biomechanical properties of tendon repair tissue without causing adverse immune reactions. To the best of our knowledge, this is the first long-term study in the literature which was accomplished to prove the use of decellularized matrix in a clinically relevant model of rat Achilles tendon and the method suggested herein might have important implications for translation into the clinic. PMID:25771002

  10. Retrieval of the retracted flexor tendons for long fingers: New tip.

    PubMed

    Ahed, K; Moujtahid, M; Nechad, M

    2014-09-01

    Zone II flexor tendon injuries continue to be a challenge for hand surgeons. During the injury event, the tendon ends may retract towards the palm. Retrieval of these lacerated ends can be problematic because the tendon sheath is unstretchable. This demanding surgery requires a precise repair technique where the tendon stumps are handled in an atraumatic manner. Microtrauma to the tendon sheath must be avoided as this can induce adhesions and lead to poor functional outcomes. Several retrieval methods for retracted tendon ends have been described in published studies. In this technical note, we will describe a technical variation that streamlines the surgical procedure and uses commonly available materials. This simple trick makes the procedure easier and avoids having to suture the tendon to the tubing. PMID:24993590

  11. Anterior superior instability with rotator cuff tearing: SLAC lesion.

    PubMed

    Savoie, F H; Field, L D; Atchinson, S

    2001-07-01

    Anterosuperior instability of the shoulder may occur from a variety of pathologic lesions. We describe a specific entity, the SLAC (superior labrum, anterior cuff) lesion that involves an association of anterior-superior labral tear with a partial supraspinatus tear. We retrospectively isolated a group of 40 patients with this lesion. The presenting complaints, physical examination findings, surgical findings, and results were isolated. Overhead activities were the most common etiology; load and shift instability testing and whipple rotator cuff testing were the most common physical examination findings. Surgical repair was successful in 37 of the 40 patients. The SLAC lesion is a definable clinical entity with predictable history, examination, surgical pathology, and satisfactory results from surgery. PMID:11888140

  12. Meniscal Root Tear Repair: Why, When and How?

    PubMed Central

    Bonasia, Davide Edoardo; Pellegrino, Pietro; D’Amelio, Andrea; Cottino, Umberto; Rossi, Roberto

    2015-01-01

    The integrity of the meniscal root insertions is fundamental to preserve correct knee kinematics and avoid degenerative changes of the knee. Injuries to the meniscal attachments can lead to meniscal extrusion, decreased contact surface, increased cartilage stress, and ultimately articular degeneration. Recent and well designed studies have clarified the anatomy and biomechanics of the medial and lateral meniscal roots. Although the treatment of meniscal root tears is still controversial, many different techniques have been described for root repair. The goal of this review is to summarize the existing knowledge regarding meniscal root tears, including anatomy, biomechanics and imaging. In addition, the most common surgical techniques, together with the clinical outcomes, are described. PMID:26330993

  13. The growth of the tearing mode - Boundary and scaling effects

    NASA Technical Reports Server (NTRS)

    Steinolfson, R. S.; Van Hoven, G.

    1983-01-01

    A numerical model of resistive magnetic tearing is developed in order to verify and relate the results of the principal approximations used in analytic analyses and to investigate the solutions and their growth-rate scalings over a large range of primary parameters which include parametric values applicable to the solar atmosphere. The computations cover the linear behavior for a variety of boundary conditions, emphasizing effects which differentiate magnetic tearing in astrophysical situations from that in laboratory devices. Eigenfunction profiles for long and short wavelengths are computed and the applicability of the 'constant psi' approximation is investigated. The growth rate is computed for values of the magnetic Reynolds number up to a trillion and of the dimensionless wavelength parameter down to 0.001. The analysis predicts significant effects due to differing values of the magnetic Reynolds number.

  14. Arthroscopic Saucerization and Repair of Discoid Lateral Meniscal Tear

    PubMed Central

    Fields, Logan K.; Caldwell, Paul E.

    2015-01-01

    Meniscal tears are among the most commonly diagnosed knee injuries and often require surgical intervention. Understanding the types of meniscal tears and treatment options is paramount to caring for the young athlete. Sports medicine and arthroscopic physicians now recognize that meniscal preservation in the young athlete is essential to the long-term health and function of the knee. Although uncommon, the discoid lateral meniscus is more prone to injury because of its increased thickness and lack of blood supply. Because of the abnormal development, the peripheral attachments are frequently absent and instability often persists after a partial meniscectomy. If the instability is unrecognized during the initial treatment, a recurrence of pain and mechanical symptoms is likely and a subsequent subtotal meniscectomy may be the only treatment option. With increased awareness, arthroscopic saucerization accompanied by arthroscopically assisted inside-out meniscal repair is a preferable treatment option with an excellent outcome. PMID:26052498

  15. Stability of short wavelength tearing and twisting modes

    SciTech Connect

    Waelbroeck, F.L.

    1998-09-22

    The stability and mutual interaction of tearing and twisting modes in a torus is governed by matrices that generalize the well-known {Delta}{prime} stability index. The diagonal elements of these matrices determine the intrinsic stability of modes that reconnect the magnetic field at a single resonant surface. The off-diagonal elements indicate the strength of the coupling between the different modes. The author shows how the elements of these matrices can be evaluated, in the limit of short wavelength, from the free energy driving radially extended ballooning modes. The author applies the results by calculating the tearing and twisting {Delta}{prime} for a model high-beta equilibrium with circular flux surfaces.

  16. Complications Following Arthroscopic Rotator Cuff Tear Repair

    PubMed Central

    Audigé, Laurent; Blum, Raphael; Müller, Andreas M.; Flury, Matthias; Durchholz, Holger

    2015-01-01

    Background Valid comparison of outcomes after surgical procedures requires consensus on which instruments and parameters should be used, including the recording and evaluation of surgical complications. An international standard outlining the terminology and definitions of surgical complications in orthopaedics is lacking. Purpose This study systematically reviewed the literature for terms and definitions related to the occurrence of negative events or complications after arthroscopic rotator cuff repair (ARCR) with specific focus on shoulder stiffness. Study Design Systematic review; Level of evidence, 4. Methods PubMed, EMBASE, Cochrane Library, and Scopus databases were searched for reviews, clinical studies, and case reports of complications associated with ARCR. Reference lists of selected articles were also screened. The terminology of complications and their definitions were extracted from all relevant original articles by a single reviewer and verified by a second reviewer. Definitions of shoulder stiffness or equivalent terms were tabulated. Results Of 654 references published after 2007 and obtained from the search, 233 full-text papers (44 reviews, 155 studies, 31 case reports, and 3 surgical technique presentations) were reviewed. Twenty-two additional references cited for a definition were checked. One report defined the term surgical complication. There were 242 different terms used to describe local events and 64 to describe nonlocal events. Furthermore, 16 definitions of terms such as frozen shoulder, shoulder stiffness, or stiff painful shoulder were identified. Diagnosis criteria for shoulder stiffness differed widely; 12 various definitions for restriction in range of motion were noted. One definition included a gradation of stiffness severity, whereas another considered the patient’s subjective assessment of motion. Conclusion The literature does not consistently report on complications after ARCR, making valid comparison of the incidence of these events among published reports impossible. Specifically, the variation in criteria used to diagnose shoulder stiffness is problematic for valid and accurate reporting of this event. A standard for reporting this event and other complications after ARCR is needed. Clinical Relevance This review serves as the basis for the development of a uniform documentation process for shoulder stiffness and the standardization of complication definitions in ARCR following international consensus.

  17. Dynamics and function of the tear film in relation to the blink cycle.

    PubMed

    Braun, R J; King-Smith, P E; Begley, C G; Li, Longfei; Gewecke, N R

    2015-03-01

    Great strides have recently been made in quantitative measurements of tear film thickness and thinning, mathematical modeling thereof and linking these to sensory perception. This paper summarizes recent progress in these areas and reports on new results. The complete blink cycle is used as a framework that attempts to unify the results that are currently available. Understanding of tear film dynamics is aided by combining information from different imaging methods, including fluorescence, retroillumination and a new high-speed stroboscopic imaging system developed for studying the tear film during the blink cycle. During the downstroke of the blink, lipid is compressed as a thick layer just under the upper lid which is often released as a narrow thick band of lipid at the beginning of the upstroke. "Rippling" of the tear film/air interface due to motion of the tear film over the corneal surface, somewhat like the flow of water in a shallow stream over a rocky streambed, was observed during lid motion and treated theoretically here. New mathematical predictions of tear film osmolarity over the exposed ocular surface and in tear breakup are presented; the latter is closely linked to new in vivo observations. Models include the effects of evaporation, osmotic flow through the cornea and conjunctiva, quenching of fluorescence, tangential flow of aqueous tears and diffusion of tear solutes and fluorescein. These and other combinations of experiment and theory increase our understanding of the fluid dynamics of the tear film and its potential impact on the ocular surface. PMID:25479602

  18. Vascular Endothelial Growth Factor in Tear Samples of Patients with Systemic Sclerosis

    PubMed Central

    Rentka, Anikó; Hársfalvi, Jolán; Berta, András; Köröskényi, Krisztina; Szekanecz, Zoltán; Szücs, Gabriella; Szodoray, Peter; Kemény-Beke, Ádám

    2015-01-01

    Background. Systemic sclerosis is an autoimmune disease, characterized by widespread small vessel vasculopathy, immune dysregulation with production of autoantibodies, and progressive fibrosis. Changes in levels of proangiogenic cytokines had already been determined largely in serum. Our aim was to assess the levels of VEGF in human tears of patients with SSC. Patients and methods. Forty-three patients (40 female and 3 men, mean (SD) age 61 (48–74) years) with SSc and 27 healthy controls were enrolled in this study. Basal tear sample collection and tear velocity investigations were carried out followed by an ophthalmological examination. Total protein concentrations and VEGF levels were determined in tear samples. Results. The average collected tear fluid volume developed 10.4??L (1.6–31.2) in patients and 15.63??L (3.68–34.5) in control subjects. The average total protein level was 6.9??g/?L (1.8–12.3) in tears of patients and control tears contained an average of 4.132??g/?L (0.1–14.1) protein. In patients with SSc the average concentration of VEGF was 4.9?pg/?L (3.5–8.1) and 6.15?pg/?L (3.84–12.3) in healthy samples. Conclusions. Total protein production was increased because of the smaller tear volume. Decreased VEGF in tear of SSc patients can be explained also by the decreased tear secretion of patients. PMID:26339137

  19. The influence of humidity, temperature, and oral contraceptive in tear

    NASA Astrophysics Data System (ADS)

    Sousa, Raul A. R. C.; Ribeiro, Tânia L. C.; Moreira, Sandra M. B.; Baptista, António M. G.

    2013-11-01

    The aim of this study is to ascertain whether the quantity and quality of tear and eye subjective comfort are influenced by the temperature, humidity and oral Contraceptives Taking or Non-taking (CTNT). Forty-one students, females, from the University of Minho, Braga, Portugal, aged (mean+/-1standard deviation) of 21.51+/-1.85 years, ranging from 20 to 30 years, participated in this study. The McMonnies Questionnaire (MMQ), Break Up Time (BUT) and Phenol Red Test (PRT) were accessed between 14-17 hours in four sets of visits throughout the year: Visit 1, Visit 2, Visit 3 and Visit 4. The PRT and BUT values (mean+/-1standard deviation) for Visit 1, Visit 2, Visit 3 and Visit 4 were respectively 23.88+/-6.50mm, 22.29+/-8.00mm, 23.61+/-6.75mm, 22.88+/-7.00mm and 6.02+/-1.58s, 5.62+/-1.22s, 5.23+/-0.88s, 5.53+/-1. 42s. The MMQ scores for Visit 1, Visit 2, Visit 3 and Visit 4 ranged from 2-13, 2-15, 1-14 and 2-14 with medians of 6, 7, 6 and 6, respectively. The influence of temperature, humidity and CTNT on PRT, BUT and MMQ were evaluated using generalized linear mixed model. For BUT and MMQ statistical significant effects were found regarding temperature and humidity. The temperature and humidity influenced the tear quality and subjective comfort but did not influence the tear quantity. The CTNT did not influence tear quantity, quality or subjective eye comfort.

  20. A threshold for excitation of neoclassical tearing modes

    SciTech Connect

    Gorelenkov, N.N.; Zakharov, L.E.; Gorelenkova, M.V.

    1996-01-01

    Stability criterion is obtained for neoclassical tearing modes. A finite amplitude of magnetic island is required for their excitation. In both collisional and collisionless regimes the threshold is determined by the ratio of the transversal and the parallel transport near the island, when the flattening of the pressure profile eliminates the bootstrap current. A number of TFTR supershots are compared with the theory. Both the stability condition and the critical island width are consistent with experimental data.

  1. Lens surface roughening for tears invariant contact lens performance

    NASA Astrophysics Data System (ADS)

    Zalevsky, Zeev; Azogui, Jonathan; Limon, Ofer; Rudnitsky, Arkady

    2014-03-01

    In many extended depth of focus diffractive or interferometry based ophthalmic contact lenses the time varied tears layers affect the ophthalmic functionality of the lens. In this paper we present a new approach involving nano pillars realized inside the grooves of a contact lens aiming to implement any type of extended depth of focus or diffractive optical element for ophthalmic applications in order to solve the micro fluidics layer uncertainty within the micro sag features.

  2. High conductivity magnetic tearing instability. [of neutral plasma sheets

    NASA Technical Reports Server (NTRS)

    Cross, M. A.; Van Hoven, G.

    1976-01-01

    Linearized equations of magnetohydrodynamics are used to investigate the tearing mode, for arbitrary values of the conductivity, through a consideration of the additional effect of the electron-inertia contribution to Ohm's law. A description is provided of the equilibrium and subsequent instability in the magnetohydrodynamic approximation. A method for solving the perturbation equations in the linear approximation is discussed and attention is given to the results in the high conductivity limit.

  3. The use of Zylon fibers in ULDB tendons

    NASA Astrophysics Data System (ADS)

    Seely, Loren; Zimmerman, Mike; McLaughlin, Joe

    2004-01-01

    Early in the development of the ultra long duration balloon (ULDB), Zylon was selected as the tendon material due to its favorable stress-strain properties. It is a next generation fiber whose strength and modulus are almost double those of the Kevlar fibers. In addition there are two versions of the Zylon, as spun (AS) and high modulus (HM). Data will be presented on why HM was chosen. Early in the development process, it was learned that this material exhibited an unusual sensitivity to degradation by ambient light. This is in addition to the expected sensitivity to UV (Ultraviolet) radiation. The fiber manufacturer reported all of these properties in their literature. Due to the operating environment of the ULDB it is necessary to protect the tendons from both visible and UV radiation. Methods to protect the tendons will be discussed. In addition, information on the long term exposure of the braided tendon over a thirty-two month period in a controlled manufacturing plant will be provided. Special testing methods will be noted.

  4. Changes in the Achilles tendon reflexes following Skylab missions

    NASA Technical Reports Server (NTRS)

    Baker, J. T.; Nicogossian, A. E.; Hoffler, G. W.; Johnson, R. L.; Hordinsky, J. R.

    1977-01-01

    Postflight measurements of Achilles tendon reflex duration on Skylab crewmen indicate a state of disequilibrium between the flexor and extensor muscle groups with an initial decrease in reflex duration. As the muscles regain strength and mass there occurs an overcompensation reflected by increased reflex duration. Finally, when a normal neuromuscular state is reached the reflex duration returns to baseline value.

  5. Longus colli tendonitis, clinical consequences of a misdiagnosis.

    PubMed

    Roldan, Carlos J; Carlson, Peter J

    2013-10-01

    Numerous pathologies diagnosed in the emergency department (ED) are treated with invasive procedures involving anesthetic and surgical risks. Retropharyngeal abscess is a serious condition requiring emergent treatment, often in need of trans-oral incision and drainage under general anesthesia. A misdiagnosis, especially after surgical treatment, might generate undesirable consequences, more so if the final diagnosis is a non-surgical pathology such as longus colli (LC) tendonitis. To discuss the etiology, differential diagnosis and treatment of LC tendonitis, a clinical condition still misdiagnosed despite advanced imaging techniques. A middle-aged man presented to a satellite ED with sore throat, neck pain and stiffness. A computed tomography (CT) scan of the neck with intravenous contrast was read as retropharyngeal abscess. He was transferred to our ED after acceptance by ear-nose-throat (ENT) surgery. He was scheduled for open incision and drainage under general anesthesia. A detailed evaluation by our ED staff revealed a nontoxic patient with no compromise of the airway. His physical exam was unrevealing and a second review of the CT demonstrated typical radiological signs for LC tendonitis. After a discussion with ENT the patient was discharged home on anti-inflammatory medications and oral steroids. He recovered well and no further intervention was needed. Longus colli tendonitis is a rare condition that mimics emergent surgical conditions. Emergency physicians are qualified to make a clinical and radiological diagnosis. While CT scan can provide a diagnosis, the primary evaluation tool is an adequate medical interview and physical exam. PMID:23932124

  6. How obesity modifies tendons (implications for athletic activities)

    PubMed Central

    Abate, Michele

    2014-01-01

    Summary Background: obesity is a well recognized risk factor for dysmetabolic and cardiovascular diseases, but can also be associated to musculo-skeletal disorders. Methods: a search of English-language articles was performed using the key search terms “obesity” or “body mass index” combined with “tendon”, or “tendinopathy”, indipendently. Results: several studies show that, in obese subjects, tendons frequently undergo to degeneration, which can progress to a symptomatic stage, with pain and functional impairment. The main histopathologic findings are a relative paucity of small collagen fibrils, expression of an impaired remodeling process, deposition of lipid droplets which can abut to tendolipomatosis, and a disorganized architecture in the tension regions. Both load-bearing and non load-bearing tendons can be affected. This suggests that systemic factors play an important pathogenetic role. Indeed, adipose tissue releases several bioactive peptides and hormones (chemerin, lipocalin, leptin and adiponectin), and cytokines responsible of a systemic state of chronic low grade inflammation. Conclusion: Physical activity is strongly recommended to stop the progression of weight gain or to bring an obese individual into the normal weight range. Therefore, leisure sport activity is useful in obese subjects, but caution is mandatory, because tendons with sub-clinical damage, when submitted to overload, can easily reach the symptomatic threshold. PMID:25489546

  7. [Carpal tunnel syndrome caused by a rare tendon variation].

    PubMed

    Kiztan, T

    1986-03-01

    The cause of carpal tunnel syndrome in a 51 year-old female patient was the attachement of the flexor digitorum superficialis tendon to the palmar aponeurosis. Variations of the musculature in the hand are not only of anatomic interest, but are also of clinical significance in so far as they may present a source of diagnostic and therapeutic errors. PMID:3699592

  8. Editorial commentary: biologic enhancement of muscle and tendon healing.

    PubMed

    Lubowitz, James H

    2015-05-01

    Review of biologic enhancement of muscle and tendon healing reveals substantial clinical study of platelet rich plasma, but an inadequate basis for evidence-based treatment recommendations. In this context, the literature shows that augmentation of rotator cuff repair is not shown to be of benefit, while treatment of knee and ankle tendinopathy and plantar fasciitis shows positive results. PMID:25953230

  9. The Dynamics of Collagen Uncrimping and Lateral Contraction in Tendon and the Effect of Ionic Concentration

    PubMed Central

    Buckley, Mark R; Sarver, Joseph J; Freedman, Benjamin R; Soslowsky, Louis J

    2013-01-01

    Under tensile loading, tendon undergoes a number of unique structural changes that govern its mechanical response. For example, stretching a tendon is known to induce both the progressive “uncrimping” of wavy collagen fibrils and extensive lateral contraction mediated by fluid flow out of the tissue. However, it is not known whether these processes are interdependent. Moreover, the rate-dependence of collagen uncrimping and its contribution to tendon’s viscoelastic mechanical properties are unknown. Therefore, the objective of this study was to a) develop a methodology allowing for simultaneous measurement of crimp, stress, axial strain and lateral contraction in tendon under dynamic loading; b) determine the interdependence of collagen uncrimping and lateral contraction by testing tendons in different swelling conditions; and c) assess how the process of collagen uncrimping depends on loading rate. Murine flexor carpi ulnaris (FCU) tendons in varying ionic environments were dynamically stretched to a set strain level and imaged through a plane polariscope with the polarizer and analyzer at a fixed angle. Analysis of the resulting images allowed for direct measurement of the crimp frequency and indirect measurement of the tendon thickness. Our findings demonstrate that collagen uncrimping and lateral contraction can occur independently and interstitial fluid impacts tendon mechanics directly. Furthermore, tensile stress, transverse contraction and degree of collagen uncrimping were all rate-dependent, suggesting that collagen uncrimping plays a role in tendon’s dynamic mechanical response. This study is the first to characterize the time-dependence of collagen uncrimping in tendon establishes structure-function relationships for healthy tendons that can be used to better understand and assess changes in tendon mechanics after disease or injury. PMID:23876711

  10. Stability of coupled tearing and twisting modes in tokamaks

    SciTech Connect

    Fitzpatrick, R.

    1994-03-01

    A dispersion relation is derived for resistive modes of arbitrary parity in a tokamak plasma. At low mode amplitude, tearing and twisting modes which have nonideal MHD behavior at only one rational surface at a time in the plasma are decoupled via sheared rotation and diamagnetic flows. At higher amplitude, more unstable {open_quote}compound{close_quote} modes develop which have nonideal behavior simultaneously at many surfaces. Such modes possess tearing parity layers at some of the nonideal surfaces, and twisting parity layers at others, but mixed parity layers are generally disallowed. At low mode number, {open_quote}compound{close_quote} modes are likely to have tearing parity layers at all of the nonideal surfaces in a very low-{beta} plasma, but twisting parity layers become more probable as the plasma {beta} is increased. At high mode number, unstable twisting modes which exceed a critical amplitude drive conventional magnetic island chains on alternate rational surfaces, to form an interlocking structure in which the O-points and X-points of neighboring chains line up.

  11. Genetic Response of Rat Supraspinatus Tendon and Muscle to Exercise

    PubMed Central

    Rooney, Sarah Ilkhanipour; Tobias, John W.; Bhatt, Pankti R.; Kuntz, Andrew F.; Soslowsky, Louis J.

    2015-01-01

    Inflammation is a complex, biologic event that aims to protect and repair tissue. Previous studies suggest that inflammation is critical to induce a healing response following acute injury; however, whether similar inflammatory responses occur as a result of beneficial, non-injurious loading is unknown. The objective of this study was to screen for alterations in a subset of inflammatory and extracellular matrix genes to identify the responses of rat supraspinatus tendon and muscle to a known, non-injurious loading condition. We sought to define how a subset of genes representative of specific inflammation and matrix turnover pathways is altered in supraspinatus tendon and muscle 1) acutely following a single loading bout and 2) chronically following repeated loading bouts. In this study, Sprague-Dawley rats in the acute group ran a single bout of non-injurious exercise on a flat treadmill (10 m/min, 1 hour) and were sacrificed 12 or 24 hours after. Rats in the chronic group ran 5 days/wk for 1 or 8 weeks. A control group maintained normal cage activity. Supraspinatus muscle and tendon were harvested for RNA extractions, and a custom Panomics QuantiGene 2.0 multiplex assay was used to detect 48 target and 3 housekeeping genes. Muscle/tendon and acute/chronic groups had distinct gene expression. Components of the arachidonic acid cascade and matrix metalloproteinases and their inhibitors were altered with acute and chronic exercise. Collagen expression increased. Using a previously validated model of non-injurious exercise, we have shown that supraspinatus tendon and muscle respond to acute and chronic exercise by regulating inflammatory- and matrix turnover-related genes, suggesting that these pathways are involved in the beneficial adaptations to exercise. PMID:26447778

  12. Genetic Response of Rat Supraspinatus Tendon and Muscle to Exercise.

    PubMed

    Rooney, Sarah Ilkhanipour; Tobias, John W; Bhatt, Pankti R; Kuntz, Andrew F; Soslowsky, Louis J

    2015-01-01

    Inflammation is a complex, biologic event that aims to protect and repair tissue. Previous studies suggest that inflammation is critical to induce a healing response following acute injury; however, whether similar inflammatory responses occur as a result of beneficial, non-injurious loading is unknown. The objective of this study was to screen for alterations in a subset of inflammatory and extracellular matrix genes to identify the responses of rat supraspinatus tendon and muscle to a known, non-injurious loading condition. We sought to define how a subset of genes representative of specific inflammation and matrix turnover pathways is altered in supraspinatus tendon and muscle 1) acutely following a single loading bout and 2) chronically following repeated loading bouts. In this study, Sprague-Dawley rats in the acute group ran a single bout of non-injurious exercise on a flat treadmill (10 m/min, 1 hour) and were sacrificed 12 or 24 hours after. Rats in the chronic group ran 5 days/wk for 1 or 8 weeks. A control group maintained normal cage activity. Supraspinatus muscle and tendon were harvested for RNA extractions, and a custom Panomics QuantiGene 2.0 multiplex assay was used to detect 48 target and 3 housekeeping genes. Muscle/tendon and acute/chronic groups had distinct gene expression. Components of the arachidonic acid cascade and matrix metalloproteinases and their inhibitors were altered with acute and chronic exercise. Collagen expression increased. Using a previously validated model of non-injurious exercise, we have shown that supraspinatus tendon and muscle respond to acute and chronic exercise by regulating inflammatory- and matrix turnover-related genes, suggesting that these pathways are involved in the beneficial adaptations to exercise. PMID:26447778

  13. The precorneal tear film as a fluid shell: the effect of blinking and saccades on tear film distribution and dynamics.

    PubMed

    Yokoi, Norihiko; Bron, Anthony J; Georgiev, Georgi As

    2014-10-01

    We conducted a series of experiments to elucidate the behavior of the human precorneal tear film (PCTF) during blinking and horizontal and vertical saccades. Methodology included video-interferometry with subsequent image cross-correlation (tear film lipid layer [TFLL]) and video-microscopy (mucoaqueous subphase [MAS]). We observed that the TFLL interference pattern deteriorates rapidly with successive blinks and degrades slowly with repeated horizontal saccades during blink suppression when dark arcs of thinning appear in the fluorescein-stained PCTF. Furthermore, after full downgaze and a return to the primary position, a transient horizontal bright band appears, deep to the spreading TFLL. It may be followed by local disturbances in the interference pattern. Two horizontal dark bands form in the stained PCTF after the return saccade. PCTF disruption may occur below the lower band during blink suppression. We concluded that shearing during horizontal saccades is insufficient to disturb the tear film structure greatly. The MAS and TFLL move together as a fluid shell. The dark arcs/bands are caused by meniscus-induced thinning, imprinted onto the PCTF at the lid margin. Their stability during blink suppression suggests that the MAS has gel-like properties. The horizontal bright bands are probably due to transient corneal indentation in downgaze. In downgaze, the disturbance of the TFLL and MAS below the dark bands is possibly due to shearing across the MAS in the return phase. This could cause desiccating stress in everyday activities, such as working at a computer. PMID:25284771

  14. A prospective multi-site registry study of a specific protocol of autologous bone marrow concentrate for the treatment of shoulder rotator cuff tears and osteoarthritis

    PubMed Central

    Centeno, Christopher J; Al-Sayegh, Hasan; Bashir, Jamil; Goodyear, Shaun; Freeman, Michael D

    2015-01-01

    Introduction Shoulder pain is a common musculoskeletal complaint in the general population. Bone marrow concentrate (BMC) injections offer promising potential as a minimally invasive approach for treatment of shoulder pain in degenerative disease. In this study, we investigated the clinical outcomes of the BMC injections for treatment of shoulder pain and disability due to osteoarthritis (OA) and rotator cuff tears in a treatment registry population. Methods A total of 115 shoulders in 102 patients were treated with autologous BMC injections for symptomatic OA at the glenohumeral joint and/or rotator cuff tears. Data were collected for factors potentially influencing outcome, including age, sex, body mass index, and the type of condition treated (ie, OA or rotator cuff tear). Clinical outcomes were assessed serially over time using the disabilities of the arm, shoulder and hand score (DASH), the numeric pain scale (NPS), and a subjective improvement rating scale. Baseline scores were compared to the most recent outcome scores at the time of the analysis and adjusted for demographic differences. We reported comparisons of pre- and post-treatment scores, the differences between osteoarthritis and rotator cuff groups, and the predictive effects on the clinical outcomes. Results At the most current follow-up assessment after treatment, the average DASH score decreased (improved) from 36.1 to 17.1 (P<0.001) and the average numeric pain scale value decreased (improved) from 4.3 to 2.4 (P<0.001). These changes were associated with an average subjective improvement of 48.8%. No differences were observed between outcomes among the shoulders treated for OA versus rotator cuff tears, nor did age, sex, or body mass index influence pain or functional outcomes. There were no significant treatment-related adverse events reported. Discussion We observed preliminarily encouraging results following BMC injections for shoulder OA and rotator cuff tears. These results serve as basis for the design of an adequately powered randomized controlled trial. PMID:26089699

  15. Visualization and reduction of a mensical capsular junction tear in the knee: an arthroscopic surgical technique.

    PubMed

    Plymale, Mickey; Fleisig, Glenn S; Kocaj, Stephen M; Cooney, William P; Evans, Timothy J; Cain, E Lyle; Dugas, Jeffrey R

    2014-11-01

    Meniscal injuries commonly occur concomitantly with anterior cruciate ligament (ACL) injuries. Although many types of meniscal injuries have been described in the literature, there has not been much focus on meniscal capsular junction (MCJ) tears. This lack of attention is concerning given that, in a survey of 67 orthopedic surgeons, 88% indicated that MCJ tears could be a source of chronic pain. In addition, we reviewed 781 ACL reconstructions at our clinic and found a 12.3% incidence of MCJ tear with primary ACL injury and a 23.6% incidence of MCJ tear with revision ACL reconstruction. In this article, we describe an arthroscopic repair technique for MCJ tears at the posterior aspect of the medial meniscus root. The repair uses an accessory posterior medial portal. The technique can also be used for significant posterior medial capsular tears. PMID:25379745

  16. Effect of solidified structure on hot tear in Al-Cu alloy

    NASA Astrophysics Data System (ADS)

    Yoshida, Y.; Esaka, H.; Shinozuka, K.

    2015-06-01

    Hot tear is the one of the biggest problems of cast products of aluminum alloy. The effect of solidified structure on the hot tear has not been clear. Therefore, this study has been carried out to correlate solidified structure and hot tear. Al-2.0 wt% Cu alloy was cast at 750 °C in a moldcavity, which could intentionally form hot tear. To change solidified structure, some amount of refiner was added to the molten alloy. Length of hot tear decreased with increasing the amount of refiner. Further, the area of fine eutectic Al2Cu increased as amount of refiner increased. These may indicate that probability of healing increased in case of equiaxed structure. Therefore, the length of hot tear decreased with increasing the amount of refiner. great care should be taken in constructing both.

  17. Tendinopathy of the long head of the biceps tendon: histopathologic analysis of the extra-articular biceps tendon and tenosynovium

    PubMed Central

    Streit, Jonathan J; Shishani, Yousef; Rodgers, Mark; Gobezie, Reuben

    2015-01-01

    Background Bicipital tendinitis is a common cause of anterior shoulder pain, but there is no evidence that acute inflammation of the extra-articular long head of the biceps (LHB) tendon is the root cause of this condition. We evaluated the histologic findings of the extra-articular portion of the LHB tendon and synovial sheath in order to compare those findings to known histologic changes seen in other tendinopathies. Methods Twenty-six consecutive patients (mean age 45.4±13.7 years) underwent an open subpectoral biceps tenodesis for anterior shoulder pain localized to the bicipital groove. Excised tendons were sent for histologic analysis. Specimens were graded using a semiquantitative scoring system to evaluate tenocyte morphology, the presence of ground substance, collagen bundle characteristics, and vascular changes. Results Chronic inflammation was noted in only two of 26 specimens, and no specimen demonstrated acute inflammation. Tenocyte enlargement and proliferation, characterized by increased roundness and size of the cell and nucleus with proteoglycan matrix expansion and myxoid degenerative changes, was found in all 26 specimens. Abundant ground substance, collagen bundle changes, and increased vascularization were visualized in all samples. Conclusion Anterior shoulder pain attributed to the biceps tendon does not appear to be due to an inflammatory process in most cases. The histologic findings of the extra-articular portion of the LHB tendon and synovial sheath are similar to the pathologic findings in de Quervain tenosynovitis at the wrist, and may be due to a chronic degenerative process similar to this and other tendinopathies of the body. PMID:25792859

  18. Tear fluid hyperosmolality increases nerve impulse activity of cold thermoreceptor endings of the cornea.

    PubMed

    Parra, Andres; Gonzalez-Gonzalez, Omar; Gallar, Juana; Belmonte, Carlos

    2014-08-01

    Dry eye disease (DED) is a multifactorial disorder affecting the composition and volume of tears. DED causes ocular surface dryness, cooling, and hyperosmolality, leading ultimately to corneal epithelium damage and reduced visual performance. Ocular discomfort is the main clinical symptom in DED. However, the peripheral neural source of such unpleasant sensations is still unclear. We analyzed in excised, superfused mouse eyes, the effect of NaCl-induced hyperosmolality (325-1005 mOsm·kg(-1)) on corneal cold thermoreceptor and polymodal nociceptor nerve terminal impulse (NTI) activity. Osmolality elevations at basal corneal temperature (33.6°C) linearly increased the ongoing NTI frequency of cold thermoreceptors, at a mean rate of 0.34 imp·s(-1)/10 mOsm. This frequency increase became significant with osmolality values greater than 340 mOsm. Comparison of cold thermoreceptor activity increase induced by a dynamic temperature reduction of 1.8°C under iso- and hyperosmolal (360-mOsm) conditions provided evidence that more than 50% of the increased firing response was attributable to hyperosmolality. Comparatively, activation of corneal polymodal nociceptor endings by hyperosmolal solutions started with values of 600 mOsm and greater. Sensitization of polymodal nociceptors by continuous perfusion with an "inflammatory soup" (bradykinin, histamine, prostaglandin E2 [PGE2], serotonin, and adenosine triphosphate [ATP]) did not enhance their activation by hyperosmolal solutions. High osmolality also altered the firing pattern and shape of cold and polymodal NTIs, possibly reflecting disturbances in local membrane currents. Results strongly suggest that tear osmolality elevations in the range observed in DED predominantly excite cold thermoreceptors, supporting the hypothesis that dryness sensations experienced by these patients are due, at least in part, to an augmented activity of corneal cold thermoreceptors. PMID:24785271

  19. Treatment of peroneal nerve injuries with simultaneous tendon transfer and nerve exploration

    PubMed Central

    2014-01-01

    Background Common peroneal nerve palsy leading to foot drop is difficult to manage and has historically been treated with extended bracing with expectant waiting for return of nerve function. Peroneal nerve exploration has traditionally been avoided except in cases of known traumatic or iatrogenic injury, with tendon transfers being performed in a delayed fashion after exhausting conservative treatment. We present a new strategy for management of foot drop with nerve exploration and concomitant tendon transfer. Method We retrospectively reviewed a series of 12 patients with peroneal nerve palsies that were treated with tendon transfer from 2005 to 2011. Of these patients, seven were treated with simultaneous peroneal nerve exploration and repair at the time of tendon transfer. Results Patients with both nerve repair and tendon transfer had superior functional results with active dorsiflexion in all patients, compared to dorsiflexion in 40% of patients treated with tendon transfers alone. Additionally, 57% of patients treated with nerve repair and tendon transfer were able to achieve enough function to return to running, compared to 20% in patients with tendon transfer alone. No patient had full return of native motor function resulting in excessive dorsiflexion strength. Conclusion The results of our limited case series for this rare condition indicate that simultaneous nerve repair and tendon transfer showed no detrimental results and may provide improved function over tendon transfer alone. PMID:25099247

  20. Release of the A4 pulley to facilitate zone II flexor tendon repair.

    PubMed

    Tang, Jin Bo

    2014-11-01

    During primary or delayed primary repair of the flexor digitorum profundus tendon, surgeons often face difficulty in passing the retracted tendon or repaired tendon under the dense, fibrous A4 pulley. The A4 pulley is the narrowest part of the flexor sheath, proximal to the terminal tendon. Disrupted tendon ends (or surgically repaired tendons) are usually swelling, making passage of the tendons under this pulley difficult or even impossible. During tendon repair in the A4 pulley area, when the trauma is in the middle part of the middle phalanx and the A3 pulley is intact, the A4 pulley can be vented entirely to accommodate surgical repair and facilitate gliding of the repaired tendon after surgery. Venting the pulley does not disturb tendon function when the other major pulleys are intact and when the venting of the A4 pulley and adjacent sheath is limited to the middle half of the middle phalanx. Such venting is easily achieved through a palmar midline or lateral incision of the A4 pulley and its adjacent distal or/and proximal sheath, which helps ensure a more predictable recovery of digital flexion and extension. PMID:25282719

  1. Biomechanical properties and histology of db/db diabetic mouse Achilles tendon

    PubMed Central

    Boivin, Gregory P.; Elenes, Egleide Y.; Schultze, Andrew K.; Chodavarapu, Harshita; Hunter, Shawn A.; Elased, Khalid M.

    2014-01-01

    Summary Foot ulcers are a severe complication of diabetic patients resulting from nerve and tendon pathologic alterations. In diabetic patients the tendons are thicker, shorter and have increased stiffness. We examined C57BL/KsJ (BKS.Cg-Dock7m +/+ Leprdb/J) (db/db) mice tendons to determine whether they are an animal model for human diabetic tendon changes. We hypothesized that the Achilles tendons of db/db diabetic mice would be thicker, stiffer, fail at lower loads and stresses, and have degenerative changes compared to control mice. Biomechanical and histologic analyses of the Achilles tendons of 16 week old db/db and control male mice were performed. There was a significant increase in tendon diameter and significant decreases in maximum load, tensile stress, stiffness and elastic modulus in tendons from diabetic mice compared to controls. Mild degenerative and neutrophil infiltration was observed near the tendon insertions on the calcaneous in 25% of db/db mice. In summary, hyper-glycemia and obesity lead to severe changes in db/db mice will be a useful model to examine mechanisms for tendon alterations. PMID:25489543

  2. Lack of tissue renewal in human adult Achilles tendon is revealed by nuclear bomb 14C

    PubMed Central

    Heinemeier, Katja Maria; Schjerling, Peter; Heinemeier, Jan; Magnusson, Stig Peter; Kjaer, Michael

    2013-01-01

    Tendons are often injured and heal poorly. Whether this is caused by a slow tissue turnover is unknown, since existing data provide diverging estimates of tendon protein half-life that range from 2 mo to 200 yr. With the purpose of determining life-long turnover of human tendon tissue, we used the 14C bomb-pulse method. This method takes advantage of the dramatic increase in atmospheric levels of 14C, produced by nuclear bomb tests in 1955–1963, which is reflected in all living organisms. Levels of 14C were measured in 28 forensic samples of Achilles tendon core and 4 skeletal muscle samples (donor birth years 1945–1983) with accelerator mass spectrometry (AMS) and compared to known atmospheric levels to estimate tissue turnover. We found that Achilles tendon tissue retained levels of 14C corresponding to atmospheric levels several decades before tissue sampling, demonstrating a very limited tissue turnover. The tendon concentrations of 14C approximately reflected the atmospheric levels present during the first 17 yr of life, indicating that the tendon core is formed during height growth and is essentially not renewed thereafter. In contrast, 14C levels in muscle indicated continuous turnover. Our observation provides a fundamental premise for understanding tendon function and pathology, and likely explains the poor regenerative capacity of tendon tissue.—Heinemeier, K. M., Schjerling, P., Heinemeier, J., Magnusson, S. P., Kjaer, M. Lack of tissue renewal in human adult Achilles tendon is revealed by nuclear bomb 14C. PMID:23401563

  3. The cellular biology of flexor tendon adhesion formation: an old problem in a new paradigm.

    PubMed

    Wong, Jason K F; Lui, Yin H; Kapacee, Zoher; Kadler, Karl E; Ferguson, Mark W J; McGrouther, Duncan A

    2009-11-01

    Intrasynovial flexor tendon injuries of the hand can frequently be complicated by tendon adhesions to the surrounding sheath, limiting finger function. We have developed a new tendon injury model in the mouse to investigate the three-dimensional cellular biology of intrasynovial flexor tendon healing and adhesion formation. We investigated the cell biology using markers for inflammation, proliferation, collagen synthesis, apoptosis, and vascularization/myofibroblasts. Quantitative immunohistochemical image analysis and three-dimensional reconstruction with cell mapping was performed on labeled serial sections. Flexor tendon adhesions were also assessed 21 days after wounding using transmission electron microscopy to examine the cell phenotypes in the wound. When the tendon has been immobilized, the mouse can form tendon adhesions in the flexor tendon sheath. The cell biology of tendon healing follows the classic wound healing response of inflammation, proliferation, synthesis, and apoptosis, but the greater activity occurs in the surrounding tissue. Cells that have multiple "fibripositors" and cells with cytoplasmic protrusions that contain multiple large and small diameter fibrils can be found in the wound during collagen synthesis. In conclusion, adhesion formation occurs due to scarring between two damaged surfaces. The mouse model for flexor tendon injury represents a new platform to study adhesion formation that is genetically tractable. PMID:19834058

  4. Equine Induced Pluripotent Stem Cells have a Reduced Tendon Differentiation Capacity Compared to Embryonic Stem Cells

    PubMed Central

    Bavin, Emma P.; Smith, Olivia; Baird, Arabella E. G.; Smith, Lawrence C.; Guest, Deborah J.

    2015-01-01

    Tendon injuries occur commonly in horses and their repair through scar tissue formation predisposes horses to a high rate of re-injury. Pluripotent stem cells may provide a cell replacement therapy to improve tendon tissue regeneration and lower the frequency of re-injury. We have previously demonstrated that equine embryonic stem cells (ESCs) differentiate into the tendon cell lineage upon injection into the damaged horse tendon and can differentiate into functional tendon cells in vitro to generate artificial tendons. Induced pluripotent stem cells (iPSCs) have now been derived from horses but, to date, there are no reports on their ability to differentiate into tendon cells. As iPSCs can be produced from adult cell types, they provide a more accessible source of cells than ESCs, which require the use of horse embryos. The aim of this study was to compare tendon differentiation by ESCs and iPSCs produced through two independent methods. In two-dimensional differentiation assays, the iPSCs expressed tendon-associated genes and proteins, which were enhanced by the presence of transforming growth factor-?3. However, in three-dimensional (3D) differentiation assays, the iPSCs failed to differentiate into functional tendon cells and generate artificial tendons. These results demonstrate the utility of the 3D in vitro tendon assay for measuring tendon differentiation and the need for more detailed studies to be performed on equine iPSCs to identify and understand their epigenetic differences from pluripotent ESCs prior to their clinical application. PMID:26664982

  5. Equine Induced Pluripotent Stem Cells have a Reduced Tendon Differentiation Capacity Compared to Embryonic Stem Cells.

    PubMed

    Bavin, Emma P; Smith, Olivia; Baird, Arabella E G; Smith, Lawrence C; Guest, Deborah J

    2015-01-01

    Tendon injuries occur commonly in horses and their repair through scar tissue formation predisposes horses to a high rate of re-injury. Pluripotent stem cells may provide a cell replacement therapy to improve tendon tissue regeneration and lower the frequency of re-injury. We have previously demonstrated that equine embryonic stem cells (ESCs) differentiate into the tendon cell lineage upon injection into the damaged horse tendon and can differentiate into functional tendon cells in vitro to generate artificial tendons. Induced pluripotent stem cells (iPSCs) have now been derived from horses but, to date, there are no reports on their ability to differentiate into tendon cells. As iPSCs can be produced from adult cell types, they provide a more accessible source of cells than ESCs, which require the use of horse embryos. The aim of this study was to compare tendon differentiation by ESCs and iPSCs produced through two independent methods. In two-dimensional differentiation assays, the iPSCs expressed tendon-associated genes and proteins, which were enhanced by the presence of transforming growth factor-?3. However, in three-dimensional (3D) differentiation assays, the iPSCs failed to differentiate into functional tendon cells and generate artificial tendons. These results demonstrate the utility of the 3D in vitro tendon assay for measuring tendon differentiation and the need for more detailed studies to be performed on equine iPSCs to identify and understand their epigenetic differences from pluripotent ESCs prior to their clinical application. PMID:26664982

  6. The effect of N-acetylcysteine on the microscopic fluid dynamics of rat tears.

    PubMed

    Tragoulias, Sophia T; Anderton, Philip J

    2001-09-01

    BACKGROUND: The classical view of the tear film is of a 10-micron film of aqueous tears, sandwiched between thin layers of lipid and mucus. This has been challenged recently by the revelation that the tear film may be considerably thicker than 10 microns and that dissolved mucus and protein may play a much more important role than simply promoting tear adherence. In particular, the primary role of mucus may be to form a structured aqueous gel that adheres closely to the corneal surface and evens out its irregularities, thus providing a high-quality optical surface. METHODS: We have used the robust tear film of the rat eye as an animal model to investigate the contribution of mucus and low-molecular-weight (LMW) proteins to tear film structure. The ocular surface was first exposed to saline, which washed away the tear film. Single drops of a tear/saline mixture, treated with various concentrations of the thiol-reducing agent N-acetylcysteine (NAC), were placed on the ocular surface and the resulting fluid behaviour was recorded with video-microscopy. RESULTS: At five per cent concentration, NAC appeared to degrade the gap-filling and anti-evaporative qualities of the tears, features that give the rat tear film its robust characteristics. Lower concentrations had no significant effect. DISCUSSION: In a previous publication, we showed that five per cent NAC alters the profile of LMW proteins in rat tears. The present observations suggest that the robust wetting properties of rat tears depend critically on their mucus and/or LMW protein content and possibly are related to the formation of an aqueous/mucous gel. PMID:12366370

  7. Tear Fluid Extracellular DNA: Diagnostic and Therapeutic Implications in Dry Eye Disease

    PubMed Central

    Tibrewal, Sapna; Sarkar, Joy; Jassim, Sarmad H.; Gandhi, Sonal; Sonawane, Snehal; Chaudhary, Shweta; Byun, Yong-Soo; Ivanir, Yair; Hallak, Joelle; Horner, John H.; Newcomb, Martin; Jain, Sandeep

    2013-01-01

    Purpose. To determine the abundance of extracellular DNA (eDNA) in tear fluid of patients with dry eye disease (DED) and to report clinical outcomes after DNase I eyedrops use to reduce excessive tear fluid eDNA. Methods. Tear fluid was collected from healthy control subjects and patients with DED. The eDNA abundance was determined with the PicoGreen dye assay. The DED symptoms and clinical signs were recorded and correlated with eDNA abundance. Two patients with DED having excessive eDNA in tear fluid were treated with DNase I eyedrops. Results. The PicoGreen dye assay measures tear fluid eDNA abundance after a 2-minute incubation time. With longer incubations, admixed cells also contribute to eDNA measurements. The mean (SE) eDNA abundance in healthy control subjects' tear fluid was 1.4 (0.2) ?g/mL. The mean (SE) eDNA abundance in tear fluid of patients with nonautoimmune DED, autoimmune DED, and graft versus host disease was significantly higher: the values were 2.9 (0.6), 5.2 (1.2), and 9.1 (2.3) ?g/mL, respectively (P < 0.05). In most of these patients, the PicoGreen dye kinetic assay of tear fluid showed an increase in fluorescence signal due to the presence of viable cells in tear fluid. Tear fluid eDNA had the best correlation with corneal Rose Bengal staining (r = 0.55). Treatment of patients having DED with DNase I eyedrops reduced eDNA abundance, abrogated signal increase, and improved comfort. Conclusions. Excessive eDNA is present in tear fluid of patients with dry eyes. A novel therapeutic approach for managing DED may be to measure eDNA abundance in tear fluid with the PicoGreen dye assay and reduce excessive amounts with DNase I eyedrops. PMID:24255046

  8. Penile fracture with two ipsilateral corporal tears and delayed presentation: A case report

    PubMed Central

    Rajih, Emad; Alenizi, Abdullah; El-Hakim, Assaad

    2015-01-01

    Although penile fracture is an infrequent injury, it is a well-described urologic emergency. It results from the rupture of the tunica albuginea of corpora cavernosa by blunt strain that mandates immediate surgical exploration. Reported cases are usually single tear unless contralateral corporal tear is present. We present a case of 56-year-old with intraoperative findings of two separate tears in the same corpus cavernosum. Clinical presentation was also delayed for 4 days post-injury and repair was performed on day 7. This case accentuates the need for a high index of suspicion to rule out concomitant ipsilateral tear. Delayed repair was possible, and full recovery ensued.

  9. The Impact of Ceramic Shell Strength on Hot Tearing during Investment Casting

    SciTech Connect

    Norouzi, Saeid; Farhangi, Hassan

    2011-01-17

    The effect of ceramic shell strength on hot tearing susceptibility during solidification was inspected practicing investment casting of the cobalt-base superalloy samples with the same casting conditions, but different ceramic shell systems. Results showed that the lower the ceramic shell strength upon using polymer additives, the lower the hindered contraction rate, and the lower the hindered contraction rate, the smaller the hot tearing tendency. Optical microscopy and electron microscopy scanning revealed that the hot tear propagated along the last solidified interdendritic phase, and that the hot tear surface had two major modes: (1) the ductile region in the outer layer; and (2) the inner region of liquid embrittlement.

  10. The Impact of Ceramic Shell Strength on Hot Tearing during Investment Casting

    NASA Astrophysics Data System (ADS)

    Norouzi, Saeid; Farhangi, Hassan

    2011-01-01

    The effect of ceramic shell strength on hot tearing susceptibility during solidification was inspected practicing investment casting of the cobalt-base superalloy samples with the same casting conditions, but different ceramic shell systems. Results showed that the lower the ceramic shell strength upon using polymer additives, the lower the hindered contraction rate, and the lower the hindered contraction rate, the smaller the hot tearing tendency. Optical microscopy and electron microscopy scanning revealed that the hot tear propagated along the last solidified interdendritic phase, and that the hot tear surface had two major modes: 1) the ductile region in the outer layer; and 2) the inner region of liquid embrittlement.

  11. Effects of intramuscular sedative and opioid combinations on tear production in dogs.

    PubMed

    Dodam, J.R.; Branson, K.R.; Martin, D.D.

    1998-01-01

    The effect of commonly used sedation protocols on tear production rate was evaluated in dogs. Schirmer I tear tests were examined before and after intramuscular injection of acepromazine and oxymorphone (ACE + OXY; n = 7), diazepam and butorphanol (DIA + BUT; n = 8), and xylazine and butorphanol (XYL + BUT; n = 8). Two Schirmer I tear tests were also performed 15-25 min apart in dogs which received no sedative drugs (control; n = 4). Tear production rate decreased to 15 +/- 2, 17 +/- 1, and 6 +/- 1 mm min-1, respectively, while control animals averaged 21 +/- 2 mm min-1 at the same time point. Because XYL + BUT profoundly decreased tear production rate, we evaluated the two drugs separately. While BUT mildly decreased tear production when given alone to dogs (18 +/- 1 mm min-1; n = 5), xylazine had no effect on tear production. Thus it appears that the two agents act synergistically to decrease tear production rate in dogs. Moreover, sterile ocular lubricant or tear replacement should be used during XYL + BUT sedation. PMID:11397211

  12. Interferometer for measuring the dynamic surface topography of a human tear film

    NASA Astrophysics Data System (ADS)

    Primeau, Brian C.; Greivenkamp, John E.

    2012-03-01

    The anterior refracting surface of the eye is the thin tear film that forms on the surface of the cornea. Following a blink, the tear film quickly smoothes and starts to become irregular after 10 seconds. This irregularity can affect comfort and vision quality. An in vivo method of characterizing dynamic tear films has been designed based upon a near-infrared phase-shifting interferometer. This interferometer continuously measures light reflected from the tear film, allowing sub-micron analysis of the dynamic surface topography. Movies showing the tear film behavior can be generated along with quantitative metrics describing changes in the tear film surface. This tear film measurement allows analysis beyond capabilities of typical fluorescein visual inspection or corneal topography and provides better sensitivity and resolution than shearing interferometry methods. The interferometer design is capable of identifying features in the tear film much less than a micron in height with a spatial resolution of about ten microns over a 6 mm diameter. This paper presents the design of the tear film interferometer along with the considerations that must be taken when designing an interferometer for on-eye diagnostics. Discussions include eye movement, design of null optics for a range of ocular geometries, and laser emission limits for on-eye interferometry.

  13. Quantitative ultrasound method for assessing stress-strain properties and the cross-sectional area of Achilles tendon

    NASA Astrophysics Data System (ADS)

    Du, Yi-Chun; Chen, Yung-Fu; Li, Chien-Ming; Lin, Chia-Hung; Yang, Chia-En; Wu, Jian-Xing; Chen, Tainsong

    2013-12-01

    The Achilles tendon is one of the most commonly observed tendons injured with a variety of causes, such as trauma, overuse and degeneration, in the human body. Rupture and tendinosis are relatively common for this strong tendon. Stress-strain properties and shape change are important biomechanical properties of the tendon to assess surgical repair or healing progress. Currently, there are rather limited non-invasive methods available for precisely quantifying the in vivo biomechanical properties of the tendons. The aim of this study was to apply quantitative ultrasound (QUS) methods, including ultrasonic attenuation and speed of sound (SOS), to investigate porcine tendons in different stress-strain conditions. In order to find a reliable method to evaluate the change of tendon shape, ultrasound measurement was also utilized for measuring tendon thickness and compared with the change in tendon cross-sectional area under different stress. A total of 15 porcine tendons of hind trotters were examined. The test results show that the attenuation and broadband ultrasound attenuation decreased and the SOS increased by a smaller magnitude as the uniaxial loading of the stress-strain upon tendons increased. Furthermore, the tendon thickness measured with the ultrasound method was significantly correlated with tendon cross-sectional area (Pearson coefficient = 0.86). These results also indicate that attenuation of QUS and ultrasonic thickness measurement are reliable and potential parameters for assessing biomechanical properties of tendons. Further investigations are needed to warrant the application of the proposed method in a clinical setting.

  14. The musculoskeletal loading profile of the thumb during pipetting based on tendon displacement.

    PubMed

    Wu, John Z; Sinsel, Erik W; Shroyer, Justin F; Welcome, Daniel E; Zhao, Kristin D; An, Kai-Nan; Buczek, Frank L

    2013-12-01

    Strong evidence indicates that highly repetitive manual work is associated with the development of upper extremity musculoskeletal disorders (MSDs). One of the occupational activities that involves highly repetitive and forceful hand work is manual pipetting in chemical or biological laboratories. In the current study, we quantified tendon displacement as a parameter to assess the cumulative loading exposure of the musculoskeletal system in the thumb during pipetting. The maximal tendon displacement was found in the flexor pollicis longus (FPL) tendon. Assuming that subjects' pipetting rates were maintained constant during a period of 1 h, the average accumulated tendon displacement in the FPL reached 29 m, which is in the lower range of those observed in other occupational activities, such as typing and nail gun operations. Our results showed that tendon displacement data contain relatively small standard deviations, despite high variances in thumb kinematics, suggesting that the tendon displacements may be useful in evaluating the musculoskeletal loading profile. PMID:24018066

  15. Biotelemetric passive sensor injected within tendon for strain and elasticity measurement.

    PubMed

    Pichorim, Sérgio Francisco; Abatti, Paulo José

    2006-05-01

    A passive and injectable (using hypodermic needle) biotelemetric sensor for measurements of tendon length changes has been developed. From these measurements tendon strain and Young's modulus of elasticity can be derived. The sensor (about 2.1 x 29 mm) is a LC circuit fixed in tendon by metallic anchors (barbs), where the value of the resonance frequency is modulated by displacement of a mobile ferrite core. The sensor was injected into digital extensor tendon of pig, allowing the determination of its stress-strain curve and, consequently, of Young's modulus of elasticity of the tendon. Practical results, such as sensitivity of 18.199 kHz/mm (correlation coefficient of 0.9891) for strains up to 5.17%, mechanical hysteresis of 6.5%, and Young's modulus of 0.9146 GPa for a pig tendon (post mortem), are presented and discussed. PMID:16686414

  16. The effect of flexor sheath integrity on nutrient uptake by chicken flexor tendons.

    PubMed

    Peterson, W W; Manske, P R; Lesker, P A

    1985-12-01

    The effect of varying degrees of flexor sheath integrity (sheath excised, incised, or incised and repaired) on the uptake of 3H-proline by chicken flexor tendons in Zone II was studied. The tendons were either: normal and uninjured, lacerated and repaired, or uninjured except for vinculum longum ligation. Different degrees of sheath integrity did not influence the uptake of 3H-proline by the tendons. The tendon does not appear to be dependent on a synovial environment for nutrients and is capable of obtaining these nutrients by diffusion from the surrounding extracellular tissue fluid. Diffusion is the primary nutrient pathway to the flexor tendon in this area, because removing its major vascular attachment (i.e., the vinculum longum) did not effect proline uptake. Careful closure of the sheath with restoration of a synovial environment does not appear to be necessary for tendon nutrition. PMID:4064412

  17. Differential scanning calorimetric studies of superficial digital flexor tendon degeneration in the horse.

    PubMed

    Miles, C A; Wardale, R J; Birch, H L; Bailey, A J

    1994-07-01

    Differential scanning calorimetry (DSC) of equine superficial digital flexor tendons revealed the presence of a small exothermic peak at 23 degrees C of unknown origin, and a large endothermic peak at 70 degrees C due to denaturation of cross-linked collagen fibres. In the central degenerated core of damaged tendons the denaturation temperature remained at 70 degrees C but the enthalpy decreased in relation to the extent of degeneration of the tendon. We suggest that this reduction in enthalpy is due to depolymerisation and denaturation of the collagen fibres. This contention is supported by the observed increased activity of the degradative enzyme cathepsin B secreted by the fibroblasts. DSC analysis of cultured porcine tendon fibroblasts revealed a multicomponent endotherm, denaturation beginning at 46 degrees C, a temperature capable of being achieved within the tendon during intensive exercise. DSC clearly has considerable potential in complementing morphological and biochemical studies to determine the aetiology and progress of equine tendon degeneration. PMID:8575396

  18. Flexor tendon repair after rupture caused by volar plate fixation of the distal radius.

    PubMed

    Rubensson, Carin C; Ydreborg, Karin; Boren, Linda; Karlander, Lars-Erik

    2015-04-01

    Volar plate fixation of unstable fractures of the distal radius is preferred by a majority of surgeons today. One known complication is the rupture of flexor tendons. The aim of this paper is to present flexor tendon ruptures after volar plate fixation analysing the clinical outcome after tendon surgery, aetiology, and methods of prevention. Seventeen consecutive ruptures in 14 patients were included. The incidence was 1.4%. Three patients declined tendon surgery. Eleven patients were treated with a free tendon graft. Only two patients showed excellent results regarding mobility in the thumb and/or fingers. Analysis of radiographs demonstrated sub-optimal placement of plate or screws in all cases. Rupture of a flexor tendon is a serious complication where the functional outcome after surgical reconstruction is uncertain. Early removal of the plate when the placement is sub-optimal or when local volar tenderness appears would probably prevent many ruptures. PMID:25162925

  19. Effect of flexor sheath integrity on nutrient uptake by chicken flexor tendons

    SciTech Connect

    Peterson, W.W.; Manske, P.R.; Lesker, P.A.

    1985-12-01

    The effect of varying degrees of flexor sheath integrity (sheath excised, incised, or incised and repaired) on the uptake of /sub 2/H-proline by chicken flexor tendons in Zone II was studied. The tendons were either: normal and uninjured, lacerated and repaired, or uninjured except for vinculum longum ligation. Different degrees of sheath integrity did not influence the uptake of /sub 2/H-proline by the tendons. The tendon does not appear to be dependent on a synovial environment for nutrients and is capable of obtaining these nutrients by diffusion from the surrounding extracellular tissue fluid. Diffusion is the primary nutrient pathway to the flexor tendon in this area, because removing its major vascular attachment (i.e., the vinculum longum) did not effect proline uptake. Careful closure of the sheath with restoration of a synovial environment does not appear to be necessary for tendon nutrition.

  20. Spring or string: does tendon elastic action influence wing muscle mechanics in bat flight?

    PubMed

    Konow, Nicolai; Cheney, Jorn A; Roberts, Thomas J; Waldman, J Rhea S; Swartz, Sharon M

    2015-10-01

    Tendon springs influence locomotor movements in many terrestrial animals, but their roles in locomotion through fluids as well as in small-bodied mammals are less clear. We measured muscle, tendon and joint mechanics in an elbow extensor of a small fruit bat during ascending flight. At the end of downstroke, the tendon was stretched by elbow flexion as the wing was folded. At the end of upstroke, elastic energy was recovered via tendon recoil and extended the elbow, contributing to unfurling the wing for downstroke. Compared with a hypothetical 'string-like' system lacking series elastic compliance, the tendon spring conferred a 22.5% decrease in muscle fascicle strain magnitude. Our findings demonstrate tendon elastic action in a small flying mammal and expand our understanding of the occurrence and action of series elastic actuator mechanisms in fluid-based locomotion. PMID:26423848

  1. Measurement of the Achilles tendon reflex for the diagnosis of lumbosacral root compression syndromes.

    PubMed Central

    Rico, R E; Jonkman, E J

    1982-01-01

    The Hoffmann reflex and the Achilles tendon reflex were measured in a group of 194 subjects suspected of having a lumbosacral root compression syndrome. The Achilles tendon reflex was elicited manually with a metal hammer. There was a high correlation between the H-M interval and the Achilles tendon reflex-M interval. The usefulness of the Achilles tendon reflex was evaluated in a selected sub-group of 61 patients with proven L5 or S1 root compression. Neither the H-reflex nor the Achilles tendon reflex appeared to be of any value in detecting L5 root compression. Both the H-reflex and the Achilles tendon reflex proved to be useful for diagnosis of S1 root compression syndromes, the latter being the more sensitive method. Images PMID:7131012

  2. Long-term results of tendon shortening trapeziometacarpal arthroplasty.

    PubMed

    Budoff, Jeffrey E; Gordon, Leonard

    2002-12-01

    Multiple soft tissue arthroplasties have been described for reconstruction of trapeziometacarpal arthritis. Trapeziectomy with abductor pollicis longus tendon shortening has been reported to have favorable short-term results, with 95% to 100% good or excellent pain relief at an average of 18 to 31 months. No long-term results of this reconstruction have been published. In the current study, 29 abductor pollicis longus shortening arthroplasties were reviewed at an average of 5.1 years. Although 83% of patients experienced good or excellent pain relief, pinch weakness, a small arthroplasty space, and first metacarpal instability were present in numerous patients. Because of these problems observed at long-term followup, the authors now use ligament reconstruction tendon interposition as the primary trapeziometacarpal arthroplasty. PMID:12461375

  3. Dynamic tracking of tendon elongation in ultrasound imaging

    NASA Astrophysics Data System (ADS)

    Karimpoor, Mahta; Screen, Hazel; Morrissey, Dylan

    2010-02-01

    The aim of this study was to evaluate the elongation of the Achilles tendon by looking at the changing position of Myo-Tendenious Junction (MTJ) using ultrasound during isometric contraction on an Isometric dynamometer. A sequence of ultrasound images in the form of movie, obtained from a unit operating at a frequency of 12MHz during isometric contraction, was analyzed offline using MATLAB to track the MTJ. This investigation has implemented important techniques for in vivo feature extraction of Achilles tendon. Prior to feature extraction, the images were filtered by anisotropic diffusion method and morphological enhancements. The cross correlation search algorithm with an adaptive mask was utilized to track MTJ by comparing adjacent segmented frames. The present method was studied on seventeen subjects, where it was able to measure the related movement accurately.

  4. Tendon cell outgrowth rates and morphology associated with kevlar-49.

    PubMed

    Zimmerman, M; Gordon, K E

    1988-12-01

    A rat tendon cell model was used to evaluate the in vitro biocompatibility of kevlar-49. The cell response to kevlar was compared to carbon AS-4 and nylon sutures. Three trials were run and cell growth rates were statistically similar for all the materials tested. A separate experiment was conducted in which the same fiber materials were placed in the same Petri dish. Again, the rates were similar for each material. Finally, the cells were observed with a scanning electron microscope, and the three classic cell morphologies associated with this tendon cell model were observed. Also, cellular attachment to the fiber and cellular encapsulation of the fiber were identical for the three materials tested. Kevlar-49 proved to be comparable to carbon AS4 and nylon sutures in terms of cellular response and cell outgrowth rates. PMID:3235468

  5. An Improved Force Feedback Control Algorithm for Active Tendons

    PubMed Central

    Guo, Tieneng; Liu, Zhifeng; Cai, Ligang

    2012-01-01

    An active tendon, consisting of a displacement actuator and a co-located force sensor, has been adopted by many studies to suppress the vibration of large space flexible structures. The damping, provided by the force feedback control algorithm in these studies, is small and can increase, especially for tendons with low axial stiffness. This study introduces an improved force feedback algorithm, which is based on the idea of velocity feedback. The algorithm provides a large damping ratio for space flexible structures and does not require a structure model. The effectiveness of the algorithm is demonstrated on a structure similar to JPL-MPI. The results show that large damping can be achieved for the vibration control of large space structures. PMID:23112660

  6. Osmotic pressure induced tensile forces in tendon collagen

    NASA Astrophysics Data System (ADS)

    Masic, Admir; Bertinetti, Luca; Schuetz, Roman; Chang, Shu-Wei; Metzger, Till Hartmut; Buehler, Markus J.; Fratzl, Peter

    2015-01-01

    Water is an important component of collagen in tendons, but its role for the function of this load-carrying protein structure is poorly understood. Here we use a combination of multi-scale experimentation and computation to show that water is an integral part of the collagen molecule, which changes conformation upon water removal. The consequence is a shortening of the molecule that translates into tensile stresses in the range of several to almost 100?MPa, largely surpassing those of about 0.3?MPa generated by contractile muscles. Although a complete drying of collagen would be relevant for technical applications, such as the fabrication of leather or parchment, stresses comparable to muscle contraction already occur at small osmotic pressures common in biological environments. We suggest, therefore, that water-generated tensile stresses may play a role in living collagen-based materials such as tendon or bone.

  7. Osmotic pressure induced tensile forces in tendon collagen

    PubMed Central

    Masic, Admir; Bertinetti, Luca; Schuetz, Roman; Chang, Shu-Wei; Metzger, Till Hartmut; Buehler, Markus J.; Fratzl, Peter

    2015-01-01

    Water is an important component of collagen in tendons, but its role for the function of this load-carrying protein structure is poorly understood. Here we use a combination of multi-scale experimentation and computation to show that water is an integral part of the collagen molecule, which changes conformation upon water removal. The consequence is a shortening of the molecule that translates into tensile stresses in the range of several to almost 100?MPa, largely surpassing those of about 0.3?MPa generated by contractile muscles. Although a complete drying of collagen would be relevant for technical applications, such as the fabrication of leather or parchment, stresses comparable to muscle contraction already occur at small osmotic pressures common in biological environments. We suggest, therefore, that water-generated tensile stresses may play a role in living collagen-based materials such as tendon or bone. PMID:25608644

  8. Multiple giant cell tumours of tendon sheath: a rare occurrence.

    PubMed

    Pathade, Smita Charandas; Kurpad, Ramkumar; Tauheed, Mohammed

    2014-01-01

    Giant Cell Tumours Of Tendon Sheath (GCTTS) are the second most frequent soft tissue tumours affecting the hand with an overall incidence of 1 in 50,000 individuals. These tumours are usually localized and solitary, with multiple GCTTS occurring rarely. Multi-centric origin is considered unusual and very few cases of multiple GCTTS have been reported till date. Here, we report a rare case of a 26-year-old female who presented with multiple painless swellings on palmar aspect of little finger of right hand since six months. Clinical diagnosis of Dupuytren's contracture was given. Intraoperative examination revealed multiple separate nodules, firmly attached to the flexor tendon synovial sheath. Histopathology showed features of GCTTS. PMID:24596760

  9. Multiple Giant Cell Tumours of Tendon Sheath: A Rare Occurrence

    PubMed Central

    Pathade, Smita Charandas; Kurpad, Ramkumar; Tauheed, Mohammed

    2014-01-01

    Giant Cell Tumours Of Tendon Sheath (GCTTS) are the second most frequent soft tissue tumours affecting the hand with an overall incidence of 1 in 50,000 individuals. These tumours are usually localized and solitary, with multiple GCTTS occurring rarely. Multi-centric origin is considered unusual and very few cases of multiple GCTTS have been reported till date. Here, we report a rare case of a 26-year-old female who presented with multiple painless swellings on palmar aspect of little finger of right hand since six months. Clinical diagnosis of Dupuytren’s contracture was given. Intraoperative examination revealed multiple separate nodules, firmly attached to the flexor tendon synovial sheath. Histopathology showed features of GCTTS. PMID:24596760

  10. Diagnosing Achilles tendon injuries in the emergency department.

    PubMed

    Gibbons, Lynda

    2013-09-01

    Achilles tendon (AT) injury is an overuse injury often seen in professional and recreational athletes. It tends to affect men, particularly those in their thirties and forties, more than women, and is typically seen in people who are intermittently active. To ensure AT ruptures are identified and treated effectively, early intervention in emergency departments (EDs) is crucial. This article discusses how advanced nurse practitioners can use their comprehensive problem-solving, clinical decision-making and clinical judgement skills to manage patients who present with suspected AT injury. It also describes the anatomy of tendon rupture, the aetiology and mechanism of injuries, and the importance of assessment and diagnostic tools, therapeutic techniques and management strategies. Finally, it considers the psychological effect this injury can have on patients, while in the ED and after discharge. A case study is included as an example of ED management. PMID:24024724

  11. Tendon Based Full Size Biped Humanoid Robot Walking Platform Design

    NASA Astrophysics Data System (ADS)

    Kuo, Chung-Hsien; Chiou, Kuo-Wei

    Actuators and gear trains of most biped humanoid robots are divergently allocated on the links of two legs. Disadvantages of such a mechanical design are complicated wiring of power cord and sensing/ control signal bundles and imprecise kinetics models of mixed link-and-actuator structures. Based on these drawbacks, this paper proposes a tendon-driven mechanism to develop a lower body structure of a full-size biped humanoid robot. The actuators are compacted as an actuator module, and they are placed at a distal site. A 12 degree-of-freedom mechanical structure is proposed with 100 cm in height and 45 kg in weight. The gait planning module is simulated and evaluated using the Matlab software. At the same time, an ARM7 based controller is developed to automatically generate walking patterns as well as to control the motors. Finally, a tendon-driven biped humanoid robot prototype is realized for practical waling control in the future.

  12. Curvature effect on tearing modes in presence of neoclassical friction

    NASA Astrophysics Data System (ADS)

    Maget, Patrick; Mellet, Nicolas; Lütjens, Hinrich; Meshcheriakov, Dmytro; Garbet, Xavier

    2013-11-01

    Neoclassical physics (here associated to the poloidal variation of the magnetic field strength along field lines in a tokamak) is well known for driving self-generated plasma current and nonlinear magnetic islands associated to it in high performance, ITER relevant plasma discharges. It is demonstrated that the neoclassical friction between a magnetic perturbation and plasma flow already impacts magnetic islands in the linear regime, by inducing a weakening of curvature stabilization for tearing modes. This conclusion holds in particular for regimes where convection is influencing the pressure dynamics, as shown using a simple analytical model and confirmed in full Magneto-Hydro-Dynamics simulations.

  13. Atomic physics effects on tokamak edge drift-tearing modes

    SciTech Connect

    Hahm, T.S.

    1993-03-01

    The effects of ionization and charge exchange on the linear stability of drift-tearing modes are analytically investigated. In particular, the linear instability threshold [Delta][sup Th], produced by ion sound wave coupling is modified. In the strongly collisional regime, the ionization breaks up the near cancellation of the perturbed electric field and the pressure gradient along the magnetic field, and increases the threshold. In the semi-collisional regime, both ionization and charge exchange act as drag on the ion parallel velocity, and consequently decrease the threshold by reducing the effectiveness of ion sound wave propagation.

  14. Atomic physics effects on tokamak edge drift-tearing modes

    SciTech Connect

    Hahm, T.S.

    1993-03-01

    The effects of ionization and charge exchange on the linear stability of drift-tearing modes are analytically investigated. In particular, the linear instability threshold {Delta}{sup Th}, produced by ion sound wave coupling is modified. In the strongly collisional regime, the ionization breaks up the near cancellation of the perturbed electric field and the pressure gradient along the magnetic field, and increases the threshold. In the semi-collisional regime, both ionization and charge exchange act as drag on the ion parallel velocity, and consequently decrease the threshold by reducing the effectiveness of ion sound wave propagation.

  15. Curvature effect on tearing modes in presence of neoclassical friction

    SciTech Connect

    Maget, Patrick; Mellet, Nicolas; Meshcheriakov, Dmytro; Garbet, Xavier; Lütjens, Hinrich

    2013-11-15

    Neoclassical physics (here associated to the poloidal variation of the magnetic field strength along field lines in a tokamak) is well known for driving self-generated plasma current and nonlinear magnetic islands associated to it in high performance, ITER relevant plasma discharges. It is demonstrated that the neoclassical friction between a magnetic perturbation and plasma flow already impacts magnetic islands in the linear regime, by inducing a weakening of curvature stabilization for tearing modes. This conclusion holds in particular for regimes where convection is influencing the pressure dynamics, as shown using a simple analytical model and confirmed in full Magneto-Hydro-Dynamics simulations.

  16. Tearing of thin sheets: Cracks interacting through an elastic ridge

    E-print Network

    Fabian Brau

    2014-12-17

    We study the interaction between two cracks propagating quasistatically during the tearing of a thin brittle sheet. We show that the cracks attract each other following a path described by a power law resulting from the competition between elastic and fracture energies. The power law exponent (8/11) is in close agreement with experiments. We also show that a second (asymptotic) regime, with an exponent of 9/8, emerges for small distances between the two crack tips due to the finite transverse curvature of the elastic ridge joining them.

  17. Tearing of thin sheets: Cracks interacting through an elastic ridge

    NASA Astrophysics Data System (ADS)

    Brau, Fabian

    2014-12-01

    We study the interaction between two cracks propagating quasistatically during the tearing of a thin brittle sheet. We show that the cracks attract each other following a path described by a power law resulting from the competition between elastic and fracture energies. The power law exponent (8 /11 ) is in close agreement with experiments. We also show that a second (asymptotic) regime, with an exponent of 9 /8 , emerges for small distances between the two crack tips due to the finite transverse curvature of the elastic ridge joining them.

  18. Effects of Increased Loading on In Vivo Tendon Properties: A Systematic Review

    PubMed Central

    WIESINGER, HANS-PETER; KÖSTERS, ALEXANDER; MÜLLER, ERICH; SEYNNES, OLIVIER R.

    2015-01-01

    ABSTRACT Introduction In vivo measurements have been used in the past two decades to investigate the effects of increased loading on tendon properties, yet the current understanding of tendon macroscopic changes to training is rather fragmented, limited to reports of tendon stiffening, supported by changes in material properties and/or tendon hypertrophy. The main aim of this review was to analyze the existing literature to gain further insights into tendon adaptations by extracting patterns of dose-response and time-course. Methods PubMed/Medline, SPORTDiscus, and Google Scholar databases were searched for studies examining the effect of training on material, mechanical, and morphological properties via longitudinal or cross-sectional designs. Results Thirty-five of 6440 peer-reviewed articles met the inclusion criteria. The key findings were i) the confirmation of a nearly systematic adaptation of tendon tissue to training, ii) the important variability in the observed changes in tendon properties between and within studies, and iii) the absence of a consistent incremental pattern regarding the dose-response or the time-course relation of tendon adaptation within the first months of training. However, long-term (years) training was associated with a larger tendon cross-sectional area, without any evidence of differences in material properties. Our analysis also highlighted several gaps in the existing literature, which may be addressed in future research. Conclusions In line with some cross-species observations about tendon design, tendon cross-sectional area allegedly constitutes the ultimate adjusting parameter to increased loading. We propose here a theoretical model placing tendon hypertrophy and adjustments in material properties as parts of the same adaptive continuum. PMID:25563908

  19. Wheat Gray Shorts for the Prevention of Slipped Tendons in Battery Brooder Chicks. 

    E-print Network

    Sherwood, R. M. (Ross Madison); Couch, James Russell

    1936-01-01

    brooders. The symptoms of slipped tendons in the advanced stages are these: the tibial-metatarsal jodnt is swollen and has a bluish-green color caused apparently by small hemorrhages in the underlying tissue, the tendons slip out of place to either side... STATION -- - A. B. CONNER, DIRECTOR COLLEGE STATION, BRAZOS COUNTY, TEXAS - BULLETIN 1 -- - JUNE, 1936 DIVISION OF POULTRY HUSBANDRY WHEAT GRAY SHORTS FOR THE PREVENTION OF SLIPPED TENDONS IN BATTERY BROODER CHICKS AGRICULTURAL AND MECHANICAL...

  20. Arthroscopic repair of the subscapularis tendon: indications, limits and technical features.

    PubMed

    Osti, Leonardo; Soldati, Francesco; Buono, Angelo Del; Buda, Matteo

    2013-01-01

    The rationale to anatomically repair this tendon is to restore the functional biomechanics of the shoulder. Clinical and imaging assessment are required before undertaking arthroscopy. In this way, associated pathologies of the biceps and labrum may be successfully addressed. The arthroscopic repair of the tendon implies to use suture anchors and reinsert the tendon itself over the footprint. Results after arthroscopy are comparable to those observed after open procedures. PMID:24367783