Science.gov

Sample records for muscle tendon allografts

  1. 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.

  2. 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

  3. Allograft reconstruction of peroneus longus and brevis tendons tears arising from a single muscular belly. Case report and surgical technique.

    PubMed

    Pellegrini, Manuel J; Adams, Samuel B; Parekh, Selene G

    2015-03-01

    Anatomic variants of the peroneal tendons may cause tendon disorders. Moreover, there is a lack of evidence on how to address chronic tendon pathology when a variant of the peroneal tendons is causing the patient's symptoms. We present a patient with an uncommon peroneal muscle presentation: a single muscular belly dividing into both the peroneus longus and brevis tendons. After extensive debridement of tendinopathic tissue, primary repair or tenodesis was not possible; therefore a unique solution for this problem was performed, reconstructing both peroneal tendons using a semitendinosus allograft.

  4. Recurrent patellar tendon rupture in a patient after intramedullary nailing of the tibia: reconstruction using an Achilles tendon allograft.

    PubMed

    Jagow, Devin M; Garcia, Branden J; Yacoubian, Stephan V; Yacoubian, Shahan V

    2015-05-01

    Various complications after intramedullary (IM) nailing of the tibia have been reported, the most common of which are anterior knee pain and symptoms similar to patella tendonitis. Complete rupture of the patellar tendon after IM nailing of the tibia has been reported on 2 occasions, in conjunction with predisposing patient factors, such as systemic disease or a proud tibial nail. Patellar tendon ruptures are disabling injuries that can be technically difficult to repair because of the poor quality of remaining tendon tissue, quadriceps muscle atrophy and/or contracture, and scar-tissue formation. Many methods have described the surgical reconstruction of the knee extensor mechanism, which is most commonly performed after total knee arthroplasty. We report the successful surgical and clinical outcome of patellar tendon reconstruction using an Achilles tendon allograft in a patient subject to late and recurrent ruptures after IM nailing of the tibia through a mid-patellar tendon-splitting approach. Seven months after tendon reconstruction, the patient exhibited full knee flexion, an extension lag of 10º, 4/5 quadriceps strength, and return to her baseline ambulatory status.

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

    PubMed

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

    2011-06-01

    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

  6. Human flexor tendon tissue engineering: revitalization of biostatic allograft scaffolds.

    PubMed

    Woon, Colin Y L; Farnebo, Simon; Schmitt, Taliah; Kraus, Armin; Megerle, Kai; Pham, Hung; Yan, Xinrui; Gambhir, Sanjiv S; Chang, James

    2012-12-01

    Cadaveric tendon allografts form a readily available and underutilized source of graft material. Because of their material properties, allografts are biomechanically and biologically superior to synthetic scaffolds. However, before clinical use, allografts must undergo decellularization to reduce immunogenicity and oxidation to increase porosity, leaving a nonvital biostatic scaffold. Ex vivo seeding, or revitalization, is thought to hasten graft incorporation and stimulate intrinsic tendon healing, permitting early mobilization and return to function. In this study, we examined physical and biochemical augmentation methods, including scaffold surface scoring (physical) and rehydration of lyophilized scaffolds in serum (biochemical). Scaffolds were divided into four groups: (1) scored scaffolds, (2) lyophilized scaffolds rehydrated in fetal calf serum (FCS), (3) scaffolds both scored and rehydrated in FCS, and (4) control scaffolds. Scaffolds were reseeded with adipose-derived stem cells (ADSCs). Reseeding efficacy was quantified by a live cell and total cell assays and qualified histologically with hematoxylin and eosin, live/dead and SYTO green nucleic acid stains, TUNEL apoptosis stains, procollagen stains, and transmission electron microscopy. Scaffold-seeded cell viability at up to 2 weeks in vitro and up to 4 weeks in vivo was demonstrated with bioluminescent imaging of scaffolds seeded with luciferase-positive ADSCs. The effect of seeding on scaffold biomechanical properties was demonstrated with evaluation of ultimate tensile stress (UTS) and an elastic modulus (EM). We found that scaffold surface scoring led to an increase in live and total cell attachment and penetration (MTS assay, p<0.001 and DNA assay, p=0.003, respectively). Histology confirmed greater total cell number in both construct core and surface in scored compared with unscored constructs. Cells reseeded on scored constructs displayed reduced apoptosis, persistent procollagen production, and

  7. Clinical allograft of a calcaneal tendon in a rhesus macaque (Macaca mulatta).

    PubMed

    Lemoy, Marie-Josee; Summers, Laura; Colagross-Schouten, Angela

    2014-09-01

    A 5.5-y-old male rhesus monkey (Macaca mulatta) housed in an outdoor field cage presented for severe trauma involving the left calcaneal tendon. Part of the management of this wound included an allograft of the calcaneal tendon from an animal that was euthanized for medical reasons. This case report describes the successful medical and surgical management of a macaque with a significant void of the calcaneal tendon. To our knowledge, this report is the first description of a successful tendon allograft in a rhesus macaque for clinical purposes.

  8. Septic arthritis following anterior cruciate ligament reconstruction using tendon allografts--Florida and Louisiana, 2000.

    PubMed

    2001-12-01

    In the United States, approximately 50,000 knee surgeries are performed each year for repairing anterior cruciate ligament (ACL) injuries. Tissue allografts frequently are used for ACL reconstruction, and septic arthritis is a rare complication of such procedures. This report describes four patients who acquired postsurgical septic arthritis probably associated with contaminated bone-tendon-bone allografts used for ACL reconstruction. Effective sterilization methods that do not functionally alter musculoskeletal tissue are needed to prevent allograft-related infections.

  9. Septic arthritis following anterior cruciate ligament reconstruction using tendon allografts--Florida and Louisiana, 2000.

    PubMed

    2001-12-01

    In the United States, approximately 50,000 knee surgeries are performed each year for repairing anterior cruciate ligament (ACL) injuries. Tissue allografts frequently are used for ACL reconstruction, and septic arthritis is a rare complication of such procedures. This report describes four patients who acquired postsurgical septic arthritis probably associated with contaminated bone-tendon-bone allografts used for ACL reconstruction. Effective sterilization methods that do not functionally alter musculoskeletal tissue are needed to prevent allograft-related infections. PMID:11770503

  10. Biomechanical Evaluation of Posterior Cruciate Ligament Reconstruction With Quadriceps Versus Achilles Tendon Bone Block Allograft

    PubMed Central

    Forsythe, Brian; Haro, Marc S.; Bogunovic, Ljiljana; Collins, Michael J.; Arns, Thomas A.; Trella, Katie J.; Shewman, Elizabeth F.; Verma, Nikhil N.; Bach, Bernard R.

    2016-01-01

    Background: Long-term studies of posterior cruciate ligament (PCL) reconstruction suggest that normal stability is not restored in the majority of patients. The Achilles tendon allograft is frequently utilized, although recently, the quadriceps tendon has been introduced as an alternative option due to its size and high patellar bone density. Purpose/Hypothesis: The purpose of this study was to compare the biomechanical strength of PCL reconstructions using a quadriceps versus an Achilles allograft. The hypothesis was that quadriceps bone block allograft has comparable mechanical properties to those of Achilles bone block allograft. Study Design: Controlled laboratory study. Methods: Twenty-nine fresh-frozen cadaveric knees were assigned to 1 of 3 groups: (1) intact PCL, (2) PCL reconstruction with Achilles tendon allograft, or (3) PCL reconstruction with quadriceps tendon allograft. After reconstruction, all supporting capsular and ligamentous tissues were removed. Posterior tibial translation was measured at neutral and 20° external rotation. Each specimen underwent a preload, 2 cyclic loading protocols of 500 cycles, then load to failure. Results: Construct creep deformation was significantly lower in the intact group compared with both Achilles and quadriceps allograft (P = .008). The intact specimens reached the greatest ultimate load compared with both reconstructions (1974 ± 752 N, P = .0001). The difference in ultimate load for quadriceps versus Achilles allograft was significant (P = .048), with the quadriceps group having greater maximum force during failure testing. No significant differences were noted between quadriceps versus Achilles allograft for differences in crosshead excursion during cyclic testing (peak-valley [P-V] extension stretch), creep deformation, or stiffness. Construct stiffness measured during the failure test was greatest in the intact group (117 ± 9 N/mm, P = .0001) compared with the Achilles (43 ± 11 N/mm) and quadriceps (43

  11. Novel treatment of a failed quadriceps tendon repair in a diabetic patient using a patella-quadriceps tendon allograft.

    PubMed

    Druskin, Sasha C; Rodeo, Scott A

    2013-07-01

    Recurrent quadriceps tendon rupture is a debilitating condition that may be challenging to treat, especially in the presence of systemic disease such as diabetes mellitus (Bedi et al., J Shoulder Elbow Surg 19:978-988, 2010; Chbnou and Frenette, Am J Physiol Regul Integr Comp Physiol 5:R952-R957, 2004; Chen et al., J Shoulder Elbow Surg 5:416-421, 2003). Many surgical treatment protocols have been proposed (Azar, in Canale and Beatty, eds., Campbell's Operative Orthopedics, Mosby/Elsevier, Philadelphia, PA, 2008; Ilan et al., J Am Acad Orthop Surg 3:192-200, 2003; Rodeo and Izawa, in Garrett et al., eds., Principles and Practice of Orthopedic Sports Medicine, Lippincott Williams & Wilkins, Philadelphia, PA, 2000). We report the case of a diabetic male with multiple treatment failures. He ultimately sustained a good outcome following treatment with a novel surgical technique that utilized a patella quadriceps tendon allograft. Tendon allograft-to-native bone healing had previously failed in this patient, so we used a bone-tendon construct allograft to provide an allograft bone-to-native bone healing site. Now, 13 months postoperative, the patient has increased strength, minimal pain, 20 ° of extensor lag and 130 ° of flexion.

  12. Effects of Trypsinization and Mineralization on Intrasynovial Tendon Allograft Healing to Bone

    PubMed Central

    Qu, Jin; van Alphen, Nick A.; Thoreson, Andrew R.; Chen, Qingshan; An, Kai-Nan; Amadio, Peter C.; Schmid, Thomas M.; Zhao, Chunfeng

    2014-01-01

    The purpose of the current study was to develop a novel technology to enhance tendon-to-bone interface healing by trypsinizing and mineralizing (TM) an intrasynovial tendon allograft in a rabbit bone tunnel model. Eight rabbit flexor digitorum profundus (FDP) tendons were used to optimize the trypsinization process. An additional 24 FDP tendons were stratified into control and TM groups; in each group, 4 tendons were used for in vitro evaluation of TM and 8 were transplanted into proximal tibial bone tunnels in rabbits. The samples were evaluated histologically and with mechanical testing at postoperative week 8. Maximum failure strength and linear stiffness were not significantly different between the control and TM tendons. A thin fibrous band of scar tissue formed at the graft-to-bone interface in the control group. However, only the TM group showed obvious new bone formation inside the tendon graft and a visible fibrocartilage layer at the bone tunnel entrance. This study is the first to explore effects of TM on the intrasynovial allograft healing to a bone tunnel. TM showed beneficial effects on chondrogenesis, osteogenesis, and integration of the intrasynovial tendon graft, but mechanical strength was the same as the control tendons in this short-term in vivo study. PMID:25611186

  13. Anterior cruciate ligament reconstruction with fresh-frozen patellar tendon allografts.

    PubMed

    Valenti, J R; Sala, D; Schweitzer, D

    1994-01-01

    A prospective study was performed on 30 patients who underwent an anterior cruciate ligament reconstruction with fresh-frozen patellar tendon allograft. An arthroscopic technique alone was used in 10 patients, and in the other 20 patients this was combined with a miniarthrotomy. After a mean follow up of 35 months, the overall functional results were satisfactory in 85%. There were no cases of infection, disease transmission or tissue rejection. Fresh-frozen patellar tendon allografts are a good method of anterior cruciate reconstruction.

  14. Anterior cruciate ligament reconstruction with fresh-frozen patellar tendon allografts.

    PubMed

    Valenti, J R; Sala, D; Schweitzer, D

    1994-01-01

    A prospective study was performed on 30 patients who underwent an anterior cruciate ligament reconstruction with fresh-frozen patellar tendon allograft. An arthroscopic technique alone was used in 10 patients, and in the other 20 patients this was combined with a miniarthrotomy. After a mean follow up of 35 months, the overall functional results were satisfactory in 85%. There were no cases of infection, disease transmission or tissue rejection. Fresh-frozen patellar tendon allografts are a good method of anterior cruciate reconstruction. PMID:8002109

  15. Biomechanical analysis of patellar tendon allografts as a function of donor age.

    PubMed

    Flahiff, C M; Brooks, A T; Hollis, J M; Vander Schilden, J L; Nicholas, R W

    1995-01-01

    We evaluated the biomechanical properties of patellar tendon allografts from donors aged 18 to 55 years. Bone-patellar tendon-bone complexes were harvested from acceptable donors and processed. Fat and soft tissue were removed, and the tendons were sectioned lengthwise leaving the central third. Area measurements were taken, and mechanical testing was performed. Specimens were pulled to failure at a rate of 10% of the initial length per second. The force at failure, tensile stress, modulus of elasticity, and percent elongation were determined for each specimen. There was no significant correlation (P > 0.05) between age and any of the mechanical properties. Load at failure ranged from 2110 to 4650 N, with a mean of 3424 N. Regression analysis showed slightly decreasing tensile stress with increasing age, but the correlation was not significant. It appears that patellar tendon allografts from donors up to age 55 have similar mechanical properties.

  16. Operative technique for human composite flexor tendon allograft procurement and engraftment.

    PubMed

    DeGeorge, Brent R; Rodeheaver, George T; Drake, David B

    2014-01-01

    Devastating volar hand injuries with significant damage to the pulley structures and fibro-osseous sheath, flexor tendons, and volar plates pose a major problem to the reconstructive hand surgeon. Despite advances in tendon handling, operative technique, and postoperative hand rehabilitation, patients who have undergone flexor tendon reconstruction are often plagued by chronic pain, stiffness, and decreased range of motion with resultant decreased ability to work and poor quality of life. Postoperative adhesion formation and lack of suitable donor material for tendon autograft are 2 fundamental problems that continue to challenge the hand surgeon. In 1967, Erle E. Peacock, Jr, described a technique of flexor tendon reconstruction using cadaveric composite flexor tendon allograft, which consisted of both the flexor digitorum profundus and superficialis tendons in their respective fibro-osseous sheaths consisting of the digital pulley structures and the underlying periosteum and volar plates. This technique never gained widespread acceptance due to concerns regarding tissue antigenicity, infectious disease transmission, and the rising popularity of the method of Hunter for silastic rod-based flexor tendon reconstruction initially described during the same period. With modern-day advances in tissue processing with acellularization and extensive donor screening for transmissible diseases, this technique should be revisited to address the reconstructive needs of patients with extensive volar soft tissue and tendon injury. Herein, we describe the operative technique of composite flexor tendon procurement and reconstruction with key modifications from the initial technique described by Peacock for improved composite construct elevation, soft tissue inset, and bony attachment.

  17. 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

  18. An Artificial Tendon with Durable Muscle Interface

    PubMed Central

    Melvin, Alan; Litsky, Alan; Mayerson, Joel; Witte, David; Melvin, David; Juncosa-Melvin, Natalia

    2010-01-01

    A coupling mechanism that can permanently fix a forcefully contracting muscle to a bone anchor or any totally inert prosthesis would meet a serious need in orthopaedics. Our group developed the OrthoCoupler™ device to satisfy these demands. The objective of this study was to test OrthoCoupler’s performance in vitro and in vivo in the goat semitendinosus tendon model. For in vitro evaluation, 40 samples were fatigue-tested, cycling at 10 load levels, n=4 each. For in vivo evaluation, the semitendinosus tendon was removed bilaterally in 8 goats. Left sides were reattached with an OrthoCoupler, and right sides were reattached using the Krackow stitch with #5 braided polyester sutures. Specimens were harvested 60 days post-surgery and assigned for biomechanics and histology. Fatigue strength of the devices in vitro was several times the contractile force of the semitendinosus muscle. The in vivo devices were built equivalent to two of the in vitro devices, providing an additional safety factor. In strength testing at necropsy, suture controls pulled out at 120.5 ± 68.3 N, whereas each OrthoCoupler was still holding after the muscle tore, remotely, at 298±111.3N (mean ± SD)(p<0.0003). Muscle tear strength was reached with the fiber-muscle composite produced in healing still soundly intact. This technology may be of value for orthopaedic challenges in oncology, revision arthroplasty, tendon transfer, and sports-injury reconstruction. PMID:19639642

  19. Sterilization effects on the mechanical properties of human bone-patellar tendon-bone allografts.

    PubMed

    Reid, James; Sikka, Robby; Tsoi, William; Narvy, Steven J; Hedman, Thomas; Lee, Thay Q; Vangsness, C Thomas

    2010-04-01

    Novel allograft processing methods are available from tissue banks to decrease disease transmission. This study evaluated the effects of 3 of these techniques on the initial mechanical properties of bone-patellar tendon-bone (BPTB) allografts: (1) aseptic harvest with low-dose radiation processing, (2) BioCleanse Tissue Processing System, and (3) Clearant Process. Ten-mm BPTB allografts were potted in an MTS 858 machine (MTS Systems Corp, Eden Prairie, Minnesota), cycled, and loaded to failure at a strain rate of 100%/s. Data were critically analyzed for graft dimensions and age and sex of donor. The 10th cycle and last cycle stiffness after 1000 cycles were measured at the toe region and at all points. The 2% yield stress (MPa), Young's modulus (MPa), elongation failure (mm), strain fracture (%), ultimate stress (MPa), and toughness (kJ) were measured. Forty-two tendons were tested (15 control, 11 BioCleanse, and 16 Clearant). No statistically significant differences were detected between the groups at their 10th cycle and last cycle stiffness (P>.05). Yield stress ranged from 19 to 28.8 MPa without a statistically significant difference (P>.05). Young's modulus ranged from 178.3 to 213.8 MPa without a statistically significant difference (P>.05). Similarly, elongation to failure, strain to failure, ultimate stress, and toughness showed no statistically significant differences among the 3 groups (P>.05). These processing techniques did not affect the time zero mechanical properties of the BPTB allograft tendons under these testing conditions. Clinical use of allografts should proceed with caution for selected patients.

  20. 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

  1. Revision anterior cruciate ligament reconstruction with bone-patellar tendon-bone allograft and extra-articular iliotibial band tenodesis.

    PubMed

    Mascarenhas, Randy; McConkey, Mark O; Forsythe, Brian; Harner, Christopher D

    2015-04-01

    Revision anterior cruciate ligament (ACL) reconstruction is a technically demanding procedure with outcomes that generally fail to reach those seen with primary ACL reconstruction. With most index procedures using autograft tissue, it is not uncommon for allograft tissue to be required for revision ACL reconstruction. Compared with autografts, allografts take longer to incorporate and lead to more episodes of instability. In this article, we describe ipsilateral iliotibial band tenodesis performed to augment use of bone-patellar tendon-bone allograft in revision ACL reconstruction. This technique adds rotational stability to protect the allograft tissue while it incorporates. PMID:25844596

  2. Revision anterior cruciate ligament reconstruction with bone-patellar tendon-bone allograft and extra-articular iliotibial band tenodesis.

    PubMed

    Mascarenhas, Randy; McConkey, Mark O; Forsythe, Brian; Harner, Christopher D

    2015-04-01

    Revision anterior cruciate ligament (ACL) reconstruction is a technically demanding procedure with outcomes that generally fail to reach those seen with primary ACL reconstruction. With most index procedures using autograft tissue, it is not uncommon for allograft tissue to be required for revision ACL reconstruction. Compared with autografts, allografts take longer to incorporate and lead to more episodes of instability. In this article, we describe ipsilateral iliotibial band tenodesis performed to augment use of bone-patellar tendon-bone allograft in revision ACL reconstruction. This technique adds rotational stability to protect the allograft tissue while it incorporates.

  3. A comprehensive approach for studying muscle-tendon mechanics.

    PubMed

    Hawkins, D; Bey, M

    1994-02-01

    A comprehensive approach for studying the mechanics of partially intact muscle-tendon (MT) complexes was developed. This approach utilizes a work station which integrates state-of-the-art equipment and software. The hardware includes a nerve stimulator, ergometer, high speed video camera and recorder, computer, and temperature regulated chamber. When used in conjunction with a small animal muscle model, the work station provides accurate control of muscle stimulation, MT length, and MT shortening or stretching velocity. Simultaneously, muscle force and both muscle and tendon kinematics can be recorded. This approach is unique in that it allows simultaneous testing of both muscle and tendon under physiological conditions. Additionally, both gross and local deformations of the muscle and tendon can be determined. Sample results from a study of a rat tibialis anterior muscle illustrate the utility of this approach.

  4. Repair of severe muscle belly lacerations using a tendon graft.

    PubMed

    Botte, M J; Gelberman, R H; Smith, D G; Silver, M A; Gellman, H

    1987-05-01

    Fourteen patients with 58 severe forearm muscle belly lacerations had muscle repair using tendon grafts. At mean follow-up of 14 months, results of manual muscle testing (N = 58) were: grade 5, 42%, grade 4, 14%, grade 3, 9%, grade 2, 9%, grade 1, 12%, and grade 0, 15%. Mean grip strength of the injured extremity, in pounds per square inch, was 33.5 compared with 83.4 on the noninjured side. Tendon excursion and joint mobility were maintained, and there were no postoperative complications. Tendon grafting of severe muscle lacerations is an effective method to overcome extensive defects.

  5. Anterior cruciate ligament reconstruction with Achilles tendon allografts in revisions and in patients older than 30.

    PubMed

    Grafe, Michael W; Kurzweil, Peter R

    2008-06-01

    We evaluated the results of anterior cruciate ligament (ACL) reconstruction using an Achilles tendon allograft in revisions and in patients older than 30. Results from 23 consecutive patients (mean age, 43 years) who underwent ACL reconstruction with fresh-frozen, irradiated (22/23) Achilles allografts were retrospectively reviewed. Seven cases were revisions. Patients were evaluated with physical examination, questionnaires, and x-rays. Twenty of the 23 patients were evaluated a mean of 28 months after surgery. There were 5 failures (21%); 3 acute failures were not evaluated at follow-up. One patient had an infection that required graft removal, 2 patients had mechanical failure of the grafts, and 2 had displacements of more than 5.5 mm as measured with a KT-1000 arthrometer. The 18 clinically successful cases had full motion, no thigh atrophy, and no effusion. Pivot shift scores were 55% A and 45% B on the International Knee Documentation Committee (IKDC) scale. Lachman scores were 40% A, 55% B, and 5% C on the IKDC scale. The KT-1000 difference was a mean of 2.9 mm at final follow-up. However, knees loosened a mean of 4.5 mm from the immediate postoperative measurements (P<.0001). Mean Lysholm and Tegner scores were 86.8 and 5.2, respectively. Tibial tunnel diameter increased by 3.1 mm on anteroposterior x-rays and 3.0 mm on lateral x-rays. Five patients developed mild medial compartment arthritis. Four of the 5 grafts with failures were from donors older than 40. Postoperative complications included deep vein thrombosis and inflammatory effusion (white blood cell count, 15,000). Twenty-one percent of ACL reconstructions with Achilles tendon allografts failed. Grafts deemed successful still had significant loosening at final follow-up. Allografts from donors older than 40 may have played a role in these failures. From the data in this study, it appears that surgeons should scrutinize the source of the allograft tissue and the age of the donor.

  6. Anterior cruciate ligament reconstruction with Achilles tendon allografts in revisions and in patients older than 30.

    PubMed

    Grafe, Michael W; Kurzweil, Peter R

    2008-06-01

    We evaluated the results of anterior cruciate ligament (ACL) reconstruction using an Achilles tendon allograft in revisions and in patients older than 30. Results from 23 consecutive patients (mean age, 43 years) who underwent ACL reconstruction with fresh-frozen, irradiated (22/23) Achilles allografts were retrospectively reviewed. Seven cases were revisions. Patients were evaluated with physical examination, questionnaires, and x-rays. Twenty of the 23 patients were evaluated a mean of 28 months after surgery. There were 5 failures (21%); 3 acute failures were not evaluated at follow-up. One patient had an infection that required graft removal, 2 patients had mechanical failure of the grafts, and 2 had displacements of more than 5.5 mm as measured with a KT-1000 arthrometer. The 18 clinically successful cases had full motion, no thigh atrophy, and no effusion. Pivot shift scores were 55% A and 45% B on the International Knee Documentation Committee (IKDC) scale. Lachman scores were 40% A, 55% B, and 5% C on the IKDC scale. The KT-1000 difference was a mean of 2.9 mm at final follow-up. However, knees loosened a mean of 4.5 mm from the immediate postoperative measurements (P<.0001). Mean Lysholm and Tegner scores were 86.8 and 5.2, respectively. Tibial tunnel diameter increased by 3.1 mm on anteroposterior x-rays and 3.0 mm on lateral x-rays. Five patients developed mild medial compartment arthritis. Four of the 5 grafts with failures were from donors older than 40. Postoperative complications included deep vein thrombosis and inflammatory effusion (white blood cell count, 15,000). Twenty-one percent of ACL reconstructions with Achilles tendon allografts failed. Grafts deemed successful still had significant loosening at final follow-up. Allografts from donors older than 40 may have played a role in these failures. From the data in this study, it appears that surgeons should scrutinize the source of the allograft tissue and the age of the donor. PMID:18716694

  7. Gamma irradiation: effects on biomechanical properties of human bone-patellar tendon-bone allografts.

    PubMed

    Fideler, B M; Vangsness, C T; Lu, B; Orlando, C; Moore, T

    1995-01-01

    Sixty 10-mm bone-patellar tendon-bone allografts from young human donors were placed into four test groups, a control fresh-frozen group and three fresh-frozen irradiated groups. The irradiated groups were exposed to 2.0, 3.0, or 4.0 Mrad of gamma irradiation. The specimens were tested to tensile failure. The initial biomechanical strength of fresh-frozen allografts was reduced up to 15% when compared with fresh-frozen controls after 2.0 Mrad of irradiation. Maximum force, strain energy, modulus, and maximum stress demonstrated a statistically significant reduction after 2.0 Mrad of irradiation (P < 0.01). Stiffness, elongation, and strain were reduced but not with statistical significance. A 10% to 24% and 19% to 46% reduction in all biomechanical properties were found after 3.0 (P < 0.005) and 4.0 (P < 0.0005) Mrad of irradiation, respectively. After irradiation with a 4.0 Mrad dose, the ultimate load was below that of reported values for the human anterior cruciate ligament. It is clinically important to observe and document changes in human ligaments that result from currently used doses of gamma irradiation. The results from this study provide important information regarding the initial biomechanical properties of fresh-frozen human bone-patellar tendon-bone allografts after bacterial sterilization with gamma irradiation. The current accepted dose for sterilization is between 1.5 and 2.5 Mrad. There appeared to be a dose-dependent effect of irradiation on all the biomechanical parameters studied. Four of seven parameters were found to be reduced after 2.0 Mrad of irradiation. Reductions were found in all parameters after 3.0 and 4.0 Mrad of irradiation.

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

    PubMed

    Tiwari, Prabhat; Kumar, Arun; Das, Rudra Nayan; 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-βPS 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

  9. The modified bone-patellar tendon-bone allograft in single-bundle anterior cruciate ligament reconstruction.

    PubMed

    Kang, Huijun; Wang, Fei

    2011-06-01

    Bone-patellar tendon-bone graft has been an attractive option for single-bundle anterior cruciate ligament reconstruction in clinical practice. However, the graft-tunnel mismatch in the proximal part of the tibial tunnel and the ultimate strength after postoperative ligamentization process have been potential problems for the traditional 10-mm wide graft. We modified the traditional bone-patellar tendon-bone allograft to make it double-layer, as an ideal substitute graft for single-bundle anterior cruciate ligament reconstruction with better graft-tunnel match and higher initial graft strength.

  10. Sensitivity of muscle force estimates to variations in muscle-tendon properties.

    PubMed

    Redl, Christian; Gfoehler, Margit; Pandy, Marcus G

    2007-04-01

    The aim of this study was to determine the sensitivity of muscle force estimates to changes in some of the parameters which are commonly used to describe models of muscle-tendon actuation. The sensitivity analysis was performed on three parameters: optimal muscle-fiber length, muscle physiological cross-sectional area (PCSA), and tendon rest length. The muscles selected for the analysis were posterior gluteus medius/minimus, vasti, soleus, and sartorius. Each parameter was perturbed from its nominal value, and an optimization problem was solved to determine the relative influence of each parameter on the calculated values of muscle force. Muscle forces were calculated for a simulated cycle of normal walking. Parameter sensitivity was quantified using two new metrics: an integrated sensitivity ratio, which quantified the effect of changing a single parameter for any muscle on the time history of force developed by that muscle; and a summed cross-sensitivity ratio, which quantified the effect of changing one parameter for any muscle on the time histories of forces developed by all of the other muscles. The results showed that muscle force estimates for walking are most sensitive to changes in tendon rest length and least sensitive to changes in muscle PCSA. For soleus, for example, the integrated sensitivity ratios for tendon rest length were an order of magnitude greater than those for muscle-fiber length and PCSA. For vasti, the integrated sensitivity ratios for tendon rest length were twice as large as those for muscle-fiber length and nearly an order of magnitude greater than those for PCSA. Overall, changes in the tendon rest lengths of vasti and soleus and changes in the fiber length of vasti were most critical to model estimates of muscle force. Our results emphasize the importance of obtaining accurate estimates of tendon rest length and muscle-fiber length, particularly for those actuators that function as prime movers during locomotion (gluteus maximus

  11. Anterior cruciate ligament reconstruction with fresh-frozen patellar tendon allografts: sixty cases with 2 years' minimum follow-up.

    PubMed

    Nín, J R; Leyes, M; Schweitzer, D

    1996-01-01

    A prospective study was performed on 101 patients who underwent an arthroscopic anterior cruciate ligament (ACL) reconstruction with fresh-frozen patellar tendon allograft (bone-patellar tendon-bone). We present the results of the first 60 patients with a minimum follow-up of 2 years. Thirty-four were men and 26 women with a mean age of 23. In 45 patients, a postoperative arthroscopy was performed, and tissue biopsies of the reconstructed ACL were obtained. Patients were evaluated according to the International Knee Documentation Committee evaluation form. After a mean follow-up of 47 months, the overall results were normal or nearly normal in 85%. Under postoperative arthroscopy, the macroscopic appearance of the implant was similar to that of a normal ligament. The ACL allograft was covered with a normal, well-vascularized synovium. There were no cases of infection, disease transmission or tissue rejection. We conclude that the use of fresh-frozen patellar tendon allografts is a good method of ACL reconstruction.

  12. Anterior cruciate ligament reconstruction with fresh-frozen patellar tendon allografts: sixty cases with 2 years' minimum follow-up.

    PubMed

    Nín, J R; Leyes, M; Schweitzer, D

    1996-01-01

    A prospective study was performed on 101 patients who underwent an arthroscopic anterior cruciate ligament (ACL) reconstruction with fresh-frozen patellar tendon allograft (bone-patellar tendon-bone). We present the results of the first 60 patients with a minimum follow-up of 2 years. Thirty-four were men and 26 women with a mean age of 23. In 45 patients, a postoperative arthroscopy was performed, and tissue biopsies of the reconstructed ACL were obtained. Patients were evaluated according to the International Knee Documentation Committee evaluation form. After a mean follow-up of 47 months, the overall results were normal or nearly normal in 85%. Under postoperative arthroscopy, the macroscopic appearance of the implant was similar to that of a normal ligament. The ACL allograft was covered with a normal, well-vascularized synovium. There were no cases of infection, disease transmission or tissue rejection. We conclude that the use of fresh-frozen patellar tendon allografts is a good method of ACL reconstruction. PMID:8961227

  13. [Isolated injury of the subscapular muscle tendon].

    PubMed

    Thielemann, F W; Kley, U; Holz, U

    1992-03-01

    Avulsion of the subscapularis tendon is caused by a combined abduction and external rotation trauma of the upper limb. Weakness of internal rotation and a positive apprehension test are clinical signs of the injury. A fracture of the lesser tuberosity in the x-ray film or a disruption of the subscapularis tendon documented in dynamic sonography of the shoulder clarify the diagnosis. Operative treatment is indicated of prevent weakness of internal rotation as well as anterior instability. This recommendation is supported by four cases with full range of motion and good anterior stability after surgery. PMID:1585252

  14. Repositioning forelimb superficialis muscles: tendon attachment and muscle activity enable active relocation of functional myofibers.

    PubMed

    Huang, Alice H; Riordan, Timothy J; Wang, Lingyan; Eyal, Shai; Zelzer, Elazar; Brigande, John V; Schweitzer, Ronen

    2013-09-16

    The muscles that govern hand motion are composed of extrinsic muscles that reside within the forearm and intrinsic muscles that reside within the hand. We find that the extrinsic muscles of the flexor digitorum superficialis (FDS) first differentiate as intrinsic muscles within the hand and then relocate as myofibers to their final position in the arm. This remarkable translocation of differentiated myofibers across a joint is dependent on muscle contraction and muscle-tendon attachment. Interestingly, the intrinsic flexor digitorum brevis (FDB) muscles of the foot are identical to the FDS in tendon pattern and delayed developmental timing but undergo limited muscle translocation, providing strong support for evolutionary homology between the FDS and FDB muscles. We propose that the intrinsic FDB pattern represents the original tetrapod limb and that translocation of the muscles to form the FDS is a mammalian evolutionary addition.

  15. 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

  16. 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

  17. Reconstruction of compound loss of lateral malleolus and lateral ankle ligaments with double-bundle Achilles tendon-bone allograft.

    PubMed

    Ko, Dukhwan; Jung, Hong-Geun; Kim, Hyeung-June; Cha, Seung-Han; Nam, Kyoung-Mo

    2014-01-01

    Open ankle fracture, including compound loss of the lateral malleolus, lateral ankle ligaments, and overlying skin, is a severe injury and can result in ankle instability and permanent disability. Treatment of this injury is challenging and requires bone grafting and soft tissue reconstruction. In the present report, we describe a unique reconstruction technique for compound loss of the lateral malleolus, lateral ankle ligaments, and the overlying skin using a double-bundle Achilles tendon-bone allograft combined with a reverse sural fasciocutaneous flap. The patient obtained a stable ankle with nearly full range of motion and displayed satisfactory function during the follow-up period.

  18. Age-related differences in Achilles tendon properties and triceps surae muscle architecture in vivo.

    PubMed

    Stenroth, Lauri; Peltonen, Jussi; Cronin, Neil J; Sipilä, Sarianna; Finni, Taija

    2012-11-01

    This study examined the concurrent age-related differences in muscle and tendon structure and properties. Achilles tendon morphology and mechanical properties and triceps surae muscle architecture were measured from 100 subjects [33 young (24 ± 2 yr) and 67 old (75 ± 3 yr)]. Motion analysis-assisted ultrasonography was used to determine tendon stiffness, Young's modulus, and hysteresis during isometric ramp contractions. Ultrasonography was used to measure muscle architectural features and size and tendon cross-sectional area. Older participants had 17% lower (P < 0.01) Achilles tendon stiffness and 32% lower (P < 0.001) Young's modulus than young participants. Tendon cross-sectional area was also 16% larger (P < 0.001) in older participants. Triceps surae muscle size was smaller (P < 0.05) and gastrocnemius medialis muscle fascicle length shorter (P < 0.05) in old compared with young. Maximal plantarflexion force was associated with tendon stiffness and Young's modulus (r = 0.580, P < 0.001 and r = 0.561, P < 0.001, respectively). Comparison between old and young subjects with similar strengths did not reveal a difference in tendon stiffness. The results suggest that regardless of age, Achilles tendon mechanical properties adapt to match the level of muscle performance. Old people may compensate for lower tendon material properties by increasing tendon cross-sectional area. Lower tendon stiffness in older subjects might be beneficial for movement economy in low-intensity locomotion and thus optimized for their daily activities.

  19. Effects of gamma irradiation on the initial mechanical and material properties of goat bone-patellar tendon-bone allografts

    SciTech Connect

    Gibbons, M.J.; Butler, D.L.; Grood, E.S.; Bylski-Austrow, D.I.; Levy, M.S.; Noyes, F.R. )

    1991-03-01

    The effects of {sup 60}Co gamma irradiation on the initial mechanical properties of the composite bone-patellar tendon-bone unit (CU) and the tendon midsubstance (TM) were studied. Frozen specimens were exposed to either 2 or 3 Mrad of gamma irradiation. Paired frozen specimens served as intraanimal controls. Treatment effects on the CU were assessed using four mechanical parameters. Effects on the TM were assessed using four material parameters measured using an optical surface-strain analysis system. The maximum force and strain energy to maximum force of the composite unit were significantly reduced 27% and 40%, respectively, after 3 Mrad of irradiation (p less than .05). Mechanical properties of the CU were not significantly altered, however, following 2 Mrad of irradiation. Based on individual paired contrasts between treatment and control, significant differences were also found in the material properties of the tendon midsubstance. The maximum stress, maximum strain, and strain energy density to maximum stress were significantly reduced following 3 Mrad, but not 2 Mrad, of irradiation. The results provide important time zero material property data, which will be useful for later anterior cruciate ligament reconstruction studies using irradiated allograft patellar tendons in the goat model and other animal models as well.

  20. Muscle-tendon glucose uptake in Achilles tendon rupture and tendinopathy before and after eccentric rehabilitation: Comparative case reports.

    PubMed

    Masood, Tahir; Kalliokoski, Kari; Bojsen-Møller, Jens; Finni, Taija

    2016-09-01

    Achilles tendon rupture (ATR) is the most common tendon rupture injury. The consequences of ATR on metabolic activity of the Achilles tendon and ankle plantarflexors are unknown. Furthermore, the effects of eccentric rehabilitation on metabolic activity patterns of Achilles tendon and ankle plantarflexors in ATR patients have not been reported thus far. We present a case study demonstrating glucose uptake (GU) in the Achilles tendon, the triceps surae, and the flexor hallucis longus of a post-surgical ATR patient before and after a 5-month eccentric rehabilitation. At baseline, three months post-surgery, all muscles and Achilles tendon displayed much higher GU in the ATR patient compared to a healthy individual despite lower plantarflexion force. After the rehabilitation, plantarflexion force increased in the operated leg while muscle GU was considerably reduced. The triceps surae muscles showed similar values to the healthy control. When compared to the healthy or a matched patient with Achilles tendon pain after 12 weeks of rehabilitation, Achilles tendon GU levels of ATR patient remained greater after the rehabilitation. Past studies have shown a shift in the metabolic fuel utilization towards glycolysis due to immobilization. Further research, combined with immuno-histological investigation, is needed to fully understand the mechanism behind excessive glucose uptake in ATR cases. PMID:27428528

  1. Sterilization with electron beam irradiation influences the biomechanical properties and the early remodeling of tendon allografts for reconstruction of the anterior cruciate ligament (ACL).

    PubMed

    Schmidt, Tanja; Hoburg, Arnd; Broziat, Christine; Smith, Mark D; Gohs, Uwe; Pruss, Axel; Scheffler, Sven

    2012-08-01

    Although allografts for anterior cruciate ligament (ACL) replacement have shown advantages compared to autografts, their use is limited due to the risk of disease transmission and the limitations of available sterilization methods. Gamma sterilization has shown detrimental effects on graft properties at the high doses required for sufficient pathogen inactivation. In our previous in vitro study on human patellar tendon allografts, Electron beam (Ebeam) irradiation showed less detrimental effects compared to gamma sterilization (Hoburg et al. in Am J Sports Med 38(6):1134-1140, 2010). To investigate the biological healing and restoration of the mechanical properties of a 34 kGy Ebeam treated tendon allograft twenty-four sheep underwent ACL replacement with either a 34 kGy Ebeam treated allograft or a non-sterilized fresh frozen allograft. Biomechanical testing of stiffness, ultimate failure load and AP-laxity as well as histological analysis to investigate cell, vessel and myofibroblast-density were performed after 6 and 12 weeks. Native sheep ACL and hamstring tendons (HAT, each n = 9) served as controls. The results of a previous study analyzing the remodeling of fresh frozen allografts (n = 12) and autografts (Auto, n = 18) with the same study design were also included in the analysis. Statistics were performed using Mann-Whitney U test followed by Bonferroni-Holm correction. Results showed significantly decreased biomechanical properties during the early remodeling period in Ebeam treated grafts and this was accompanied with an increased remodeling activity. There was no recovery of biomechanical function from 6 to 12 weeks in this group in contrast to the results observed in fresh frozen allografts and autografts. Therefore, high dose Ebeam irradiation investigated in this paper cannot be recommended for soft tissue allograft sterilization.

  2. Histopathological and biomechanical evaluation of tenocyte seeded allografts on rat Achilles tendon regeneration.

    PubMed

    Güngörmüş, Cansın; 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.

  3. Temporalis Muscle Tendon Unit Transfer for Smile Restoration After Facial Paralysis.

    PubMed

    Owusu Boahene, Kofi D

    2016-02-01

    Temporalis muscle tendon unit (MTU) transfer may be used as a single-stage procedure for dynamic reanimation of the paralyzed face. Principles and biomechanics of muscle function and tendon transposition are essential in optimizing outcome. Critical steps and pearls for success include minimizing scarring, maintaining glide plains, mobilizing adequate tendon length, insertion of MTU at ideal tension based on intraoperative dynamic tension-excursion relationship, and insertion of tendon as close to the lip margin as possible. Because muscles adapt to tension, load, and task changes by altering their sarcomere arrangement and muscle fiber composition, physiotherapy should be initiated to use the repurposed temporalis MTU for smile restoration.

  4. The series elastic shock absorber: tendon elasticity modulates energy dissipation by muscle during burst deceleration.

    PubMed

    Konow, Nicolai; Roberts, Thomas J

    2015-04-01

    During downhill running, manoeuvring, negotiation of obstacles and landings from a jump, mechanical energy is dissipated via active lengthening of limb muscles. Tendon compliance provides a 'shock-absorber' mechanism that rapidly absorbs mechanical energy and releases it more slowly as the recoil of the tendon does work to stretch muscle fascicles. By lowering the rate of muscular energy dissipation, tendon compliance likely reduces the risk of muscle injury that can result from rapid and forceful muscle lengthening. Here, we examine how muscle-tendon mechanics are modulated in response to changes in demand for energy dissipation. We measured lateral gastrocnemius (LG) muscle activity, force and fascicle length, as well as leg joint kinematics and ground-reaction force, as turkeys performed drop-landings from three heights (0.5-1.5 m centre-of-mass elevation). Negative work by the LG muscle-tendon unit during landing increased with drop height, mainly owing to greater muscle recruitment and force as drop height increased. Although muscle strain did not increase with landing height, ankle flexion increased owing to increased tendon strain at higher muscle forces. Measurements of the length-tension relationship of the muscle indicated that the muscle reached peak force at shorter and likely safer operating lengths as drop height increased. Our results indicate that tendon compliance is important to the modulation of energy dissipation by active muscle with changes in demand and may provide a mechanism for rapid adjustment of function during deceleration tasks of unpredictable intensity. PMID:25716796

  5. [Traumatic muscle and tendon ruptures of the lower extremities in sport: adductor muscles, M. rectus femoris and M. biceps femoris].

    PubMed

    Krüger-Franke, M

    2010-12-01

    Ruptures of the adductor muscles, the M. rectus femoris or the M. biceps femoris are sports injuries which need quick and reliable diagnostic management. Treatment of muscle injuries is mostly conservative; complete tendon ruptures or avulsion fractures of the tendons are treated operatively according to the dislocation and the functional loss.

  6. Tendon material properties vary and are interdependent among turkey hindlimb muscles

    PubMed Central

    Matson, Andrew; Konow, Nicolai; Miller, Samuel; Konow, Pernille P.; Roberts, Thomas J.

    2012-01-01

    SUMMARY The material properties of a tendon affect its ability to store and return elastic energy, resist damage, provide mechanical feedback and amplify or attenuate muscle power. While the structural properties of a tendon are known to respond to a variety of stimuli, the extent to which material properties vary among individual muscles remains unclear. We studied the tendons of six different muscles in the hindlimb of Eastern wild turkeys to determine whether there was variation in elastic modulus, ultimate tensile strength and resilience. A hydraulic testing machine was used to measure tendon force during quasi-static lengthening, and a stress–strain curve was constructed. There was substantial variation in tendon material properties among different muscles. Average elastic modulus differed significantly between some tendons, and values for the six different tendons varied nearly twofold, from 829±140 to 1479±106 MPa. Tendons were stretched to failure, and the stress at failure, or ultimate tensile stress, was taken as a lower-limit estimate of tendon strength. Breaking tests for four of the tendons revealed significant variation in ultimate tensile stress, ranging from 66.83±14.34 to 112.37±9.39 MPa. Resilience, or the fraction of energy returned in cyclic length changes was generally high, and one of the four tendons tested was significantly different in resilience from the other tendons (range: 90.65±0.83 to 94.02±0.71%). An analysis of correlation between material properties revealed a positive relationship between ultimate tensile strength and elastic modulus (r2=0.79). Specifically, stiffer tendons were stronger, and we suggest that this correlation results from a constrained value of breaking strain, which did not vary significantly among tendons. This finding suggests an interdependence of material properties that may have a structural basis and may explain some adaptive responses observed in studies of tendon plasticity. PMID:22771746

  7. Tendon material properties vary and are interdependent among turkey hindlimb muscles.

    PubMed

    Matson, Andrew; Konow, Nicolai; Miller, Samuel; Konow, Pernille P; Roberts, Thomas J

    2012-10-15

    The material properties of a tendon affect its ability to store and return elastic energy, resist damage, provide mechanical feedback and amplify or attenuate muscle power. While the structural properties of a tendon are known to respond to a variety of stimuli, the extent to which material properties vary among individual muscles remains unclear. We studied the tendons of six different muscles in the hindlimb of Eastern wild turkeys to determine whether there was variation in elastic modulus, ultimate tensile strength and resilience. A hydraulic testing machine was used to measure tendon force during quasi-static lengthening, and a stress-strain curve was constructed. There was substantial variation in tendon material properties among different muscles. Average elastic modulus differed significantly between some tendons, and values for the six different tendons varied nearly twofold, from 829±140 to 1479±106 MPa. Tendons were stretched to failure, and the stress at failure, or ultimate tensile stress, was taken as a lower-limit estimate of tendon strength. Breaking tests for four of the tendons revealed significant variation in ultimate tensile stress, ranging from 66.83±14.34 to 112.37±9.39 MPa. Resilience, or the fraction of energy returned in cyclic length changes was generally high, and one of the four tendons tested was significantly different in resilience from the other tendons (range: 90.65±0.83 to 94.02±0.71%). An analysis of correlation between material properties revealed a positive relationship between ultimate tensile strength and elastic modulus (r(2)=0.79). Specifically, stiffer tendons were stronger, and we suggest that this correlation results from a constrained value of breaking strain, which did not vary significantly among tendons. This finding suggests an interdependence of material properties that may have a structural basis and may explain some adaptive responses observed in studies of tendon plasticity. PMID:22771746

  8. The energetic benefits of tendon springs in running: is the reduction of muscle work important?

    PubMed

    Holt, Natalie C; Roberts, Thomas J; Askew, Graham N

    2014-12-15

    The distal muscle-tendon units of cursorial species are commonly composed of short muscle fibres and long, compliant tendons. It is assumed that the ability of these tendons to store and return mechanical energy over the course of a stride, thus avoiding the cyclic absorption and regeneration of mechanical energy by active muscle, offers some metabolic energy savings during running. However, this assumption has not been tested directly. We used muscle ergometry and myothermic measurements to determine the cost of force production in muscles acting isometrically, as they could if mechanical energy was stored and returned by tendon, and undergoing active stretch-shorten cycles, as they would if mechanical energy was absorbed and regenerated by muscle. We found no detectable difference in the cost of force production in isometric cycles compared with stretch-shorten cycles. This result suggests that replacing muscle stretch-shorten work with tendon elastic energy storage and recovery does not reduce the cost of force production. This calls into question the assumption that reduction of muscle work drove the evolution of long distal tendons. We propose that the energetic benefits of tendons are derived primarily from their effect on muscle and limb architecture rather than their ability to reduce the cyclic work of muscle.

  9. 'Serious thigh muscle strains': beware the intramuscular tendon which plays an important role in difficult hamstring and quadriceps muscle strains.

    PubMed

    Brukner, Peter; Connell, David

    2016-02-01

    Why do some hamstring and quadriceps strains take much longer to repair than others? Which injuries are more prone to recurrence? Intramuscular tendon injuries have received little attention as an element in 'muscle strain'. In thigh muscles, such as rectus femoris and biceps femoris, the attached tendon extends for a significant distance within the muscle belly. While the pathology of most muscle injures occurs at a musculotendinous junction, at first glance the athlete appears to report pain within a muscle belly. In addition to the musculotendinous injury being a site of pathology, the intramuscular tendon itself is occasionally injured. These injuries have a variety of appearances on MRIs. There is some evidence that these injuries require a prolonged rehabilitation time and may have higher recurrence rates. Therefore, it is important to recognise the tendon component of a thigh 'muscle strain'.

  10. Coordinated Development of Muscles and Tendon-Like Structures: Early Interactions in the Drosophila Leg

    PubMed Central

    Soler, Cedric; Laddada, Lilia; Jagla, Krzysztof

    2016-01-01

    The formation of the musculoskeletal system is a remarkable example of tissue assembly. In both vertebrates and invertebrates, precise connectivity between muscles and skeleton (or exoskeleton) via tendons or equivalent structures is fundamental for movement and stability of the body. The molecular and cellular processes underpinning muscle formation are well-established and significant advances have been made in understanding tendon development. However, the mechanisms contributing to proper connection between these two tissues have received less attention. Observations of coordinated development of tendons and muscles suggest these tissues may interact during the different steps in their development. There is growing evidence that, depending on animal model and muscle type, these interactions can take place from progenitor induction to the final step of the formation of the musculoskeletal system. Here, we briefly review and compare the mechanisms behind muscle and tendon interaction throughout the development of vertebrates and Drosophila before going on to discuss our recent findings on the coordinated development of muscles and tendon-like structures in Drosophila leg. By altering apodeme formation (the functional Drosophila equivalent of tendons in vertebrates) during the early steps of leg development, we affect the spatial localization of subsequent myoblasts. These findings provide the first evidence of the developmental impact of early interactions between muscle and tendon-like precursors, and confirm the appendicular Drosophila muscle system as a valuable model for studying these processes. PMID:26869938

  11. 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.

  12. Spring or string: does tendon elastic action influence wing muscle mechanics in bat flight?

    PubMed Central

    Konow, Nicolai; Cheney, Jorn A.; Roberts, Thomas J.; Waldman, J. Rhea S.; Swartz, Sharon M.

    2015-01-01

    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

  13. 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 ...

  14. IMPROVEMENT OF TENDON REPAIR USING MUSCLE GRAFTS TRANSDUCED WITH TGF-β1 cDNA

    PubMed Central

    Majewski, Martin; Porter, Ryan M.; Betz, Oliver B.; Betz, Volker M.; Clahsen, Harald; Flückiger, Rudolf; Evans, Christopher H.

    2015-01-01

    Tendon rupture is a common injury. Inadequate endogenous repair often leaves patients symptomatic, with tendons susceptible to re-rupture. Administration of certain growth factors improves tendon healing in animal models, but their delivery remains a challenge. Here we evaluated the delivery of TGF-β1 to tendon defects by the implantation of genetically modified muscle grafts. Rat muscle biopsies were transduced with recombinant adenovirus encoding TGF-β1 and grafted onto surgically transected Achilles tendons in recipient animals. Tissue regenerates were compared to those of controls by biomechanical testing as well as histochemical and immunohistochemical analyses. Healing was greatly accelerated when genetically modified grafts were implanted into tendon defects, with the resulting repair tissue gaining nearly normal histological appearance as early as 2 weeks postoperatively. This was associated with decreased deposition of type III collagen in favour of large fibre bundles indicative of type I collagen. These differences in tendon composition coincided with accelerated restoration of mechanical strength. Tendon thickness increased in gene-treated animals at weeks 1 and 2, but by week 8 became significantly lower than that of controls suggesting accelerated remodelling. Thus localised TGF-β1 delivery via adenovirus-modified muscle grafts improved tendon healing in this rat model and holds promise for clinical application. PMID:22354460

  15. The series elastic shock absorber: tendon elasticity modulates energy dissipation by muscle during burst deceleration

    PubMed Central

    Konow, Nicolai; Roberts, Thomas J.

    2015-01-01

    During downhill running, manoeuvring, negotiation of obstacles and landings from a jump, mechanical energy is dissipated via active lengthening of limb muscles. Tendon compliance provides a ‘shock-absorber’ mechanism that rapidly absorbs mechanical energy and releases it more slowly as the recoil of the tendon does work to stretch muscle fascicles. By lowering the rate of muscular energy dissipation, tendon compliance likely reduces the risk of muscle injury that can result from rapid and forceful muscle lengthening. Here, we examine how muscle–tendon mechanics are modulated in response to changes in demand for energy dissipation. We measured lateral gastrocnemius (LG) muscle activity, force and fascicle length, as well as leg joint kinematics and ground-reaction force, as turkeys performed drop-landings from three heights (0.5–1.5 m centre-of-mass elevation). Negative work by the LG muscle–tendon unit during landing increased with drop height, mainly owing to greater muscle recruitment and force as drop height increased. Although muscle strain did not increase with landing height, ankle flexion increased owing to increased tendon strain at higher muscle forces. Measurements of the length–tension relationship of the muscle indicated that the muscle reached peak force at shorter and likely safer operating lengths as drop height increased. Our results indicate that tendon compliance is important to the modulation of energy dissipation by active muscle with changes in demand and may provide a mechanism for rapid adjustment of function during deceleration tasks of unpredictable intensity. PMID:25716796

  16. Morphological and mechanical properties of muscle and tendon in highly trained sprinters.

    PubMed

    Kubo, Keitaro; Ikebukuro, Toshihiro; Yata, Hideaki; Tomita, Minoru; Okada, Masaji

    2011-11-01

    The purpose of this study was to investigate muscle and tendon properties in highly trained sprinters and their relations to running performance. Fifteen sprinters and 15 untrained subjects participated in this study. Muscle thickness and tendon stiffness of knee extensors and plantar flexors were measured. Sprinter muscle thickness was significantly greater than that of the untrained subjects for plantar flexors, but not for knee extensors (except for the medial side). Sprinter tendon stiffness was significantly lower than that of the untrained subjects for knee extensors, but not for plantar flexors. The best official record of a 100-m race was significantly correlated to the muscle thickness of the medial side for knee extensors. In conclusion, the tendon structures of highly trained sprinters are more compliant than those of untrained subjects for knee extensors, but not for plantar flexors. Furthermore, a thicker medial side of knee extensors was associated with greater sprinting performance.

  17. Physiotherapeutic treatment of athletic injuries to the muscle--tendon complex of the leg.

    PubMed Central

    Wise, D. D.

    1977-01-01

    An overview is presented of the most common soft-tissue injuries of the leg in athletes. A simple classification is made on the basis of cause, location of the injury and severity. These injuries can be classified into direct and indirect types. Direct injuries, which are usually the result of one episode of trauma, can be classified further into three grades of severity. Treatment is based on the severity of the injury and its location in the muscle--tendon complex. Indirect muscle--tendon injuries are the result of repetitive subacute microtrauma to the muscle--tendon complex or injury to the structures associated with muscle function (bursa, tendon sheath or fascia). Appropriate treatment regimens are suggested. PMID:902209

  18. Elastic modulus of muscle and tendon with shear wave ultrasound elastography: variations with different technical settings.

    PubMed

    Kot, Brian Chin Wing; Zhang, Zhi Jie; Lee, Arthur Wai Chun; Leung, Vivian Yee Fong; Fu, Siu Ngor

    2012-01-01

    Standardization on Shear wave ultrasound elastography (SWUE) technical settings will not only ensure that the results are accurate, but also detect any differences over time that may be attributed to true physiological changes. The present study evaluated the variations of elastic modulus of muscle and tendon using SWUE when different technical aspects were altered. The results of this study indicated that variations of elastic modulus of muscle and tendon were found when different transducer's pressure and region of interest (ROI)'s size were applied. No significant differences in elastic modulus of the rectus femoris muscle and patellar tendon were found with different acquisition times of the SWUE sonogram. The SWUE on the muscle and tendon should be performed with the lightest transducer's pressure, a shorter acquisition time for the SWUE sonogram, while measuring the mean elastic modulus regardless the ROI's size.

  19. Passive Muscle-Tendon Unit Gearing Is Joint Dependent in Human Medial Gastrocnemius

    PubMed Central

    Hodson-Tole, Emma F.; Wakeling, James M.; Dick, Taylor J. M.

    2016-01-01

    Skeletal muscles change length and develop force both passively and actively. Gearing allows muscle fiber length changes to be uncoupled from those of the whole muscle-tendon unit. During active contractions this process allows muscles to operate at mechanically favorable conditions for power or economical force production. Here we ask whether gearing is constant in passive muscle; determining the relationship between fascicle and muscle-tendon unit length change in the bi-articular medial gastrocnemius and investigating the influence of whether motion occurs at the knee or ankle joint. Specifically, the same muscle-tendon unit length changes were elicited by rotating either the ankle or knee joint whilst simultaneously measuring fascicle lengths in proximal and distal muscle regions using B-mode ultrasound. In both the proximal and distal muscle region, passive gearing values differed depending on whether ankle or knee motion occurred. Fascicle length changes were greater with ankle motion, likely reflecting anatomical differences in proximal and distal passive tendinous tissues, as well as shape changes of the adjacent mono-articular soleus. This suggests that there is joint-dependent dissociation between the mechanical behavior of muscle fibers and the muscle-tendon unit during passive joint motions that may be important to consider when developing accurate models of bi-articular muscles. PMID:27014093

  20. TGF-β superfamily signaling in muscle and tendon adaptation to resistance exercise

    PubMed Central

    Gumucio, Jonathan P; Sugg, Kristoffer B; Mendias, Christopher L

    2015-01-01

    Numerous studies in muscle and tendon have identified a central role of the TGF-β superfamily of cytokines in the regulation of extracellular matrix growth and remodeling, protein degradation, and cell proliferation and differentiation. Here we provide a novel framework for TGF-β and myostatin signaling in controlling the coordinated adaptation of both skeletal muscle and tendon tissue to resistance training. PMID:25607281

  1. Human ankle plantar flexor muscle-tendon mechanics and energetics during maximum acceleration sprinting.

    PubMed

    Lai, Adrian; Schache, Anthony G; Brown, Nicholas A T; Pandy, Marcus G

    2016-08-01

    Tendon elastic strain energy is the dominant contributor to muscle-tendon work during steady-state running. Does this behaviour also occur for sprint accelerations? We used experimental data and computational modelling to quantify muscle fascicle work and tendon elastic strain energy for the human ankle plantar flexors (specifically soleus and medial gastrocnemius) for multiple foot contacts of a maximal sprint as well as for running at a steady-state speed. Positive work done by the soleus and medial gastrocnemius muscle fascicles decreased incrementally throughout the maximal sprint and both muscles performed more work for the first foot contact of the maximal sprint (FC1) compared with steady-state running at 5 m s(-1) (SS5). However, the differences in tendon strain energy for both muscles were negligible throughout the maximal sprint and when comparing FC1 to SS5. Consequently, the contribution of muscle fascicle work to stored tendon elastic strain energy was greater for FC1 compared with subsequent foot contacts of the maximal sprint and compared with SS5. We conclude that tendon elastic strain energy in the ankle plantar flexors is just as vital at the start of a maximal sprint as it is at the end, and as it is for running at a constant speed. PMID:27581481

  2. Orientation of tendons in vivo with active and passive knee muscles.

    PubMed

    Aalbersberg, Sietske; Kingma, Idsart; Ronsky, Janet L; Frayne, Richard; van Dieën, Jaap H

    2005-09-01

    Tendon orientations in knee models are often taken from cadaver studies. The aim of this study was to investigate the effect of muscle activation on tendon orientation in vivo. Magnetic resonance imaging (MRI) images of the knee were made during relaxation and isometric knee extensions and flexions with 0 degrees , 15 degrees and 30 degrees of knee joint flexion. For six tendons, the orientation angles in sagittal and frontal plane were calculated. In the sagittal plane, muscle activation pulled the patellar tendon to a more vertical orientation and the semitendinosus and sartorius tendons to a more posterior orientation. In the frontal plane, the semitendinosus had a less lateral orientation, the biceps femoris a more medial orientation and the patellar tendon less medial orientation in loaded compared to unloaded conditions. The knee joint angle also influenced the tendon orientations. In the sagittal plane, the patellar tendon had a more anterior orientation near full extension and the biceps femoris had an anterior orientation with 0 degrees and 15 degrees flexions and neutral with 30 degrees flexions. Within 0 degrees to 30 degrees of flexion, the biceps femoris cannot produce a posterior shear force and the anterior angle of the patellar tendon is always larger than the hamstring tendons. Therefore, co-contraction of the hamstring and quadriceps is unlikely to reduce anterior shear forces in knee angles up to 30 degrees . Finally, inter-individual variation in tendon angles was large. This suggests that the amount of shear force produced and the potential to counteract shear forces by co-contraction is subject-specific. PMID:16023464

  3. The series-elastic shock absorber: tendons attenuate muscle power during eccentric actions

    PubMed Central

    Azizi, Emanuel

    2010-01-01

    Elastic tendons can act as muscle power amplifiers or energy-conserving springs during locomotion. We used an in situ muscle-tendon preparation to examine the mechanical function of tendons during lengthening contractions, when muscles absorb energy. Force, length, and power were measured in the lateral gastrocnemius muscle of wild turkeys. Sonomicrometry was used to measure muscle fascicle length independently from muscle-tendon unit (MTU) length, as measured by a muscle lever system (servomotor). A series of ramp stretches of varying velocities was applied to the MTU in fully activated muscles. Fascicle length changes were decoupled from length changes imposed on the MTU by the servomotor. Under most conditions, muscle fascicles shortened on average, while the MTU lengthened. Energy input to the MTU during the fastest lengthenings was −54.4 J/kg, while estimated work input to the muscle fascicles during this period was only −11.24 J/kg. This discrepancy indicates that energy was first absorbed by elastic elements, then released to do work on muscle fascicles after the lengthening phase of the contraction. The temporary storage of energy by elastic elements also resulted in a significant attenuation of power input to the muscle fascicles. At the fastest lengthening rates, peak instantaneous power input to the MTU reached −2,143.9 W/kg, while peak power input to the fascicles was only −557.6 W/kg. These results demonstrate that tendons may act as mechanical buffers by limiting peak muscle forces, lengthening rates, and power inputs during energy-absorbing contractions. PMID:20507964

  4. Development of the stapedius muscle and unilateral agenesia of the tendon of the stapedius muscle in a human fetus.

    PubMed

    Rodríguez-Vázquez, J F; Mérida-Velasco, J R; Verdugo-López, S

    2010-01-01

    The objective was to analyze the development of the stapedius muscle to understand an isolated unilateral absence of the tendon of the stapedius muscle in a human fetus. The study was made on 50 human embryos and fetuses aged 38 days to 17 weeks post-conception. The stapedius muscle was formed by two anlagen, one for the tendon, which derives from the internal segment of the interhyale and another for the belly, located in the second pharyngeal arch, medially to the facial nerve and near the interhyale. In the interhyale, two segments were observed forming an angle and delimited by the attachment of the belly of the stapedius muscle. The internal segment will form the tendon. The lateral segment of the interhyale was attached to the cranial end of the Reichert's cartilage (laterohyale), and normally it disappears at the beginning of the fetal period. The right unilateral agenesia of the tendon of the stapedius muscle, observed for the first time in a human fetus of 14 weeks post-conception development (PCd), was brought about by the lack of formation or the regression of the internal segment of the interhyale. It presented a belly of the stapedius muscle with an anomalous arrangement, and with a pseudo tendon originated by the persistence of the external segment of the interhyale.

  5. Acute and chronic effects of hyperbaric oxygen therapy on blood circulation of human muscle and tendon in vivo.

    PubMed

    Kubo, Keitaro; Ikebukuro, Toshihiro

    2012-10-01

    This study aimed to investigate the acute and chronic effects of hyperbaric oxygen therapy on blood circulation of human muscle and tendon in vivo. Using near-infrared spectroscopy and red laser lights, we determined acute changes in blood volume (THb) and oxygen saturation (StO2) of the medial gastrocnemius muscle and Achilles tendon during 60 minutes of hyperbaric oxygen therapy (1.3 atm absolute and 50% O2, experiment 1). In addition, we determined the chronic effects of hyperbaric oxygen therapy (60 minutes, 2 times per week, 6 weeks) on THb and StO2 of muscle and tendon (experiment 2). In experiment 1, THb of the muscle increased gradually from resting level, but StO2 did not change. On the other hand, THb and StO2 of the tendon increased during hyperbaric oxygen therapy. In experiment 2, the pattern of changes in the measured variables during 60 minutes of therapy was similar for both the muscle and tendon between the first and last therapies. During resting, THb and StO2 of the tendon were significantly lower after 6 weeks of therapy, although those of the muscle were not. In conclusion, oxygen saturation of the tendon increased during hyperbaric oxygen therapy, whereas that of the muscle did not. This result would be related to the difference in the treated effects between muscle and tendon. However, oxygen saturation of the tendon, but not the muscle, during resting decreased after 6 weeks of therapy.

  6. Anterior Cruciate Ligament Reconstruction Using a Combination of Autograft and Allograft Tendon

    PubMed Central

    Darnley, James E.; Léger-St-Jean, Benjamin; Pedroza, Angela D.; Flanigan, David C.; Kaeding, Christopher C.; Magnussen, Robert A.

    2016-01-01

    Background: Anterior cruciate ligament (ACL) reconstruction with hamstring autografts less than 8.5 mm in diameter is associated with worse patient-reported outcome scores and increased risk of revision surgery compared with reconstructions performed with larger grafts. One proposed solution to small autograft harvest is to create a hybrid graft by augmenting autografts with allograft tissue to increase graft diameter. Purpose: To compare hybrid autograft/allograft ACL reconstruction to autograft ACL reconstruction, specifically analyzing the patient-reported outcome scores and the risk of revision surgery at 2 years postoperative. Study Design: Cohort study; Level of evidence, 3. Methods: From the years 2002 to 2009, a total of 34 patients were identified from a prospectively collected database as having undergone hybrid ACL reconstruction. Twenty-seven of 34 (79.4%) patients had a 2-year follow-up. These 27 patients were matched by age (within 1 year) and sex to 27 patients who underwent hamstring autograft ACL reconstruction during the same period. At the 2-year mark, revision surgery risk and patient-reported outcome scores were compared between the 2 groups. Results: The mean age for the hybrid and matched groups (±SD) was 20.9 ± 7.0 years. Both the hybrid and control groups had 17 males and 10 females. There was no significant difference in preoperative patient-reported outcome scores, meniscus tears, or cartilage lesions between the 2 groups. Graft size was larger in the hybrid group (9.5 ± 0.6 mm) than in the autograft group (8.4 ± 0.9 mm) (P < .001). At 2 years postoperative, patient-reported outcome scores were similar between the hybrid and autograft groups. Revision surgery was required in 5 (18.5%) patients who underwent hybrid reconstruction compared with 2 (7.4%) of those who underwent autograft reconstruction (P = .26). Conclusion: Patients who undergo ACL reconstruction with hybrid hamstring grafts and hamstring autografts report similar

  7. Hox11 genes are required for regional patterning and integration of muscle, tendon and bone.

    PubMed

    Swinehart, Ilea T; Schlientz, Aleesa J; Quintanilla, Christopher A; Mortlock, Douglas P; Wellik, Deneen M

    2013-11-01

    Development of the musculoskeletal system requires precise integration of muscles, tendons and bones. The molecular mechanisms involved in the differentiation of each of these tissues have been the focus of significant research; however, much less is known about how these tissues are integrated into a functional unit appropriate for each body position and role. Previous reports have demonstrated crucial roles for Hox genes in patterning the axial and limb skeleton. Loss of Hox11 paralogous gene function results in dramatic malformation of limb zeugopod skeletal elements, the radius/ulna and tibia/fibula, as well as transformation of the sacral region to a lumbar phenotype. Utilizing a Hoxa11eGFP knock-in allele, we show that Hox11 genes are expressed in the connective tissue fibroblasts of the outer perichondrium, tendons and muscle connective tissue of the zeugopod region throughout all stages of development. Hox11 genes are not expressed in differentiated cartilage or bone, or in vascular or muscle cells in these regions. Loss of Hox11 genes disrupts regional muscle and tendon patterning of the limb in addition to affecting skeletal patterning. The tendon and muscle defects in Hox11 mutants are independent of skeletal patterning events as disruption of tendon and muscle patterning is observed in Hox11 compound mutants that do not have a skeletal phenotype. Thus, Hox genes are not simply regulators of skeletal morphology as previously thought, but are key factors that regulate regional patterning and integration of the musculoskeletal system.

  8. Human Leg Model Predicts Ankle Muscle-Tendon Morphology, State, Roles and Energetics in Walking

    PubMed Central

    Krishnaswamy, Pavitra; Brown, Emery N.; Herr, Hugh M.

    2011-01-01

    A common feature in biological neuromuscular systems is the redundancy in joint actuation. Understanding how these redundancies are resolved in typical joint movements has been a long-standing problem in biomechanics, neuroscience and prosthetics. Many empirical studies have uncovered neural, mechanical and energetic aspects of how humans resolve these degrees of freedom to actuate leg joints for common tasks like walking. However, a unifying theoretical framework that explains the many independent empirical observations and predicts individual muscle and tendon contributions to joint actuation is yet to be established. Here we develop a computational framework to address how the ankle joint actuation problem is resolved by the neuromuscular system in walking. Our framework is founded upon the proposal that a consideration of both neural control and leg muscle-tendon morphology is critical to obtain predictive, mechanistic insight into individual muscle and tendon contributions to joint actuation. We examine kinetic, kinematic and electromyographic data from healthy walking subjects to find that human leg muscle-tendon morphology and neural activations enable a metabolically optimal realization of biological ankle mechanics in walking. This optimal realization (a) corresponds to independent empirical observations of operation and performance of the soleus and gastrocnemius muscles, (b) gives rise to an efficient load-sharing amongst ankle muscle-tendon units and (c) causes soleus and gastrocnemius muscle fibers to take on distinct mechanical roles of force generation and power production at the end of stance phase in walking. The framework outlined here suggests that the dynamical interplay between leg structure and neural control may be key to the high walking economy of humans, and has implications as a means to obtain insight into empirically inaccessible features of individual muscle and tendons in biomechanical tasks. PMID:21445231

  9. The effect of tendon on muscle force in dynamic isometric contractions: a simulation study.

    PubMed

    van Soest, A J; Huijing, P A; Solomonow, M

    1995-07-01

    Recently, Baratta and Solomonow J. Biomechanics 24, 109-116 (1991) studied the effect of tendon on muscle-tendon complex behavior in cat tibialis anterior (TA) muscle. This was done by determining the relation between neural stimulation and muscle force in a dynamic isometric experiment, both before and after the removal of the distal tendon. From their results, Baratta and Solomonow concluded that in isometric and concentric contractions at mid-range force levels, tendon behaves as a rigid force conductor. This conclusion is in conflict with literature in which several functions are attributed to the elastic behavior of the series elastic element (SEE), of which tendon is the major part. The present study investigates the expected generalizability of their findings, by simulating the experiments using a straightforward Hill-type muscle model. First, model predictions are shown to be in line with the experimental results on cat TA: in dynamic isometric experiments at mid-range force levels, the effect of SEE removal is indeed negligible. Second, the effect of SEE removal is predicted to vary largely among muscles. Third, the most important determinants of the effect of SEE removal in dynamic isometric contractions are shown to be maximum fiber shortening velocity and the ratio of SEE slack length to fibre optimum length. PMID:7657678

  10. Triceps surae muscle-tendon properties in older endurance- and sprint-trained athletes.

    PubMed

    Stenroth, Lauri; Cronin, Neil J; Peltonen, Jussi; Korhonen, Marko T; Sipilä, Sarianna; Finni, Taija

    2016-01-01

    Previous studies have shown that aging is associated with alterations in muscle architecture and tendon properties (Morse CI, Thom JM, Birch KM, Narici MV. Acta Physiol Scand 183: 291-298, 2005; Narici MV, Maganaris CN, Reeves ND, Capodaglio P. J Appl Physiol 95: 2229-2234, 2003; Stenroth L, Peltonen J, Cronin NJ, Sipila S, Finni T. J Appl Physiol 113: 1537-1544, 2012). However, the possible influence of different types of regular exercise loading on muscle architecture and tendon properties in older adults is poorly understood. To address this, triceps surae muscle-tendon properties were examined in older male endurance (OE, n = 10, age = 74.0 ± 2.8 yr) and sprint runners (OS, n = 10, age = 74.4 ± 2.8 yr), with an average of 42 yr of regular training experience, and compared with age-matched [older control (OC), n = 33, age = 74.8 ± 3.6 yr] and young untrained controls (YC, n = 18, age = 23.7 ± 2.0 yr). Compared with YC, Achilles tendon cross-sectional area (CSA) was 22% (P = 0.022), 45% (P = 0.001), and 71% (P < 0.001) larger in OC, OE, and OS, respectively. Among older groups, OS had significantly larger tendon CSA compared with OC (P = 0.033). No significant between-group differences were observed in Achilles tendon stiffness. In older groups, Young's modulus was 31-44%, and maximal tendon stress 44-55% lower, than in YC (P ≤ 0.001). OE showed shorter soleus fascicle length than both OC (P < 0.05) and YC (P < 0.05). These data suggest that long-term running does not counteract the previously reported age-related increase in tendon CSA, but, instead, may have an additive effect. The greatest Achilles tendon CSA was observed in OS followed by OE and OC, suggesting that adaptation to running exercise is loading intensity dependent. Achilles tendon stiffness was maintained in older groups, even though all older groups displayed larger tendon CSA and lower tendon Young's modulus. Shorter soleus muscle fascicles in OE runners may be an adaptation to life

  11. Subject-Specific Tendon-Aponeurosis Definition in Hill-Type Model Predicts Higher Muscle Forces in Dynamic Tasks

    PubMed Central

    Gerus, Pauline; Rao, Guillaume; Berton, Eric

    2012-01-01

    Neuromusculoskeletal models are a common method to estimate muscle forces. Developing accurate neuromusculoskeletal models is a challenging task due to the complexity of the system and large inter-subject variability. The estimation of muscles force is based on the mechanical properties of tendon-aponeurosis complex. Most neuromusculoskeletal models use a generic definition of the tendon-aponeurosis complex based on in vitro test, perhaps limiting their validity. Ultrasonography allows subject-specific estimates of the tendon-aponeurosis complex’s mechanical properties. The aim of this study was to investigate the influence of subject-specific mechanical properties of the tendon-aponeurosis complex on a neuromusculoskeletal model of the ankle joint. Seven subjects performed isometric contractions from which the tendon-aponeurosis force-strain relationship was estimated. Hopping and running tasks were performed and muscle forces were estimated using subject-specific tendon-aponeurosis and generic tendon properties. Two ultrasound probes positioned over the muscle-tendon junction and the mid-belly were combined with motion capture to estimate the in vivo tendon and aponeurosis strain of the medial head of gastrocnemius muscle. The tendon-aponeurosis force-strain relationship was scaled for the other ankle muscles based on tendon and aponeurosis length of each muscle measured by ultrasonography. The EMG-driven model was calibrated twice - using the generic tendon definition and a subject-specific tendon-aponeurosis force-strain definition. The use of subject-specific tendon-aponeurosis definition leads to a higher muscle force estimate for the soleus muscle and the plantar-flexor group, and to a better model prediction of the ankle joint moment compared to the model estimate which used a generic definition. Furthermore, the subject-specific tendon-aponeurosis definition leads to a decoupling behaviour between the muscle fibre and muscle-tendon unit in agreement with

  12. Subject-specific tendon-aponeurosis definition in Hill-type model predicts higher muscle forces in dynamic tasks.

    PubMed

    Gerus, Pauline; Rao, Guillaume; Berton, Eric

    2012-01-01

    Neuromusculoskeletal models are a common method to estimate muscle forces. Developing accurate neuromusculoskeletal models is a challenging task due to the complexity of the system and large inter-subject variability. The estimation of muscles force is based on the mechanical properties of tendon-aponeurosis complex. Most neuromusculoskeletal models use a generic definition of the tendon-aponeurosis complex based on in vitro test, perhaps limiting their validity. Ultrasonography allows subject-specific estimates of the tendon-aponeurosis complex's mechanical properties. The aim of this study was to investigate the influence of subject-specific mechanical properties of the tendon-aponeurosis complex on a neuromusculoskeletal model of the ankle joint. Seven subjects performed isometric contractions from which the tendon-aponeurosis force-strain relationship was estimated. Hopping and running tasks were performed and muscle forces were estimated using subject-specific tendon-aponeurosis and generic tendon properties. Two ultrasound probes positioned over the muscle-tendon junction and the mid-belly were combined with motion capture to estimate the in vivo tendon and aponeurosis strain of the medial head of gastrocnemius muscle. The tendon-aponeurosis force-strain relationship was scaled for the other ankle muscles based on tendon and aponeurosis length of each muscle measured by ultrasonography. The EMG-driven model was calibrated twice - using the generic tendon definition and a subject-specific tendon-aponeurosis force-strain definition. The use of subject-specific tendon-aponeurosis definition leads to a higher muscle force estimate for the soleus muscle and the plantar-flexor group, and to a better model prediction of the ankle joint moment compared to the model estimate which used a generic definition. Furthermore, the subject-specific tendon-aponeurosis definition leads to a decoupling behaviour between the muscle fibre and muscle-tendon unit in agreement with

  13. Control of Organization and Function of Muscle and Tendon by Thrombospondin-4

    PubMed Central

    Frolova, Ella G.; Drazba, Judith; Krukovets, Irene; Kostenko, Volodymyr; Blech, Lauren; Harry, Christy; Vasanji, Amit; Drumm, Carla; Sul, Pavel; Jenniskens, Guido J.; Plow, Edward F.; Stenina-Adognravi, Olga

    2014-01-01

    Thrombospondins (TSP) are multifunctional proteins that are deposited in the extracellular matrix where they directly affect the function of vascular and other cell types. TSP-4, one of the 5 TSP family members, is expressed abundantly in tendon and muscle. We have examined the effect of TSP-4 deficiency on tendon collagen and skeletal muscle morphology and function. In Thbs4−/− mice, tendon collagen fibrils are significantly larger than in wild-type mice, and there is no compensatory over-expression of TSP-3 and TSP-5, the two TSPs most highly homologous to TSP-4, in the deficient mice. TSP-4 is expressed in skeletal muscle, and higher levels of TSP-4 protein are associated with the microvasculature of red skeletal muscle with high oxidative metabolism. Lack of TSP-4 in Medial soleus, red skeletal muscle with predominant oxidative metabolism, is associated with decreased levels of several specific glycosaminoglycan modifications, decreased expression of a TGFβ receptor beta-glycan, decreased activity of lipoprotein lipase, which associates with vascular cell surfaces by binding to glycosaminoglycans, and decreased uptake of VLDL. The soleus muscle is smaller and hind- and fore-limb grip strength is reduced in Thbs4−/− mice compared to wild-type mice. These observations suggest that TSP-4 regulates the composition of the ECM at major sites of its deposition, tendon and muscle, and the absence of TSP-4 alters the organization, composition and physiological functions of these tissues. PMID:24589453

  14. Isokinetic eccentric exercise can induce skeletal muscle injury within the physiologic excursion of muscle-tendon unit: a rabbit model

    PubMed Central

    Tsuang, Yang-Hwei; Lam, Shui-Ling; Wu, Lien-Chen; Chiang, Chang-Jung; Chen, Li-Ting; Chen, Pei-Yu; Sun, Jui-Sheng; Wang, Chien-Che

    2007-01-01

    Background and Purpose Intensive eccentric exercise can cause muscle damage. We simulated an animal model of isokinetic eccentric exercise by repetitively stretching stimulated triceps surae muscle-tendon units to determine if such exercise affects the mechanical properties of the unit within its physiologic excursion. Methods Biomechanical parameters of the muscle-tendon unit were monitored during isokinetic eccentric loading in 12 rabbits. In each animal, one limb (control group) was stretched until failure. The other limb (study group) was first subjected to isokinetic and eccentric cyclic loading at the rate of 10.0 cm/min to 112% (group I) or 120% (group II) of its initial length for 1 hour and then stretched to failure. Load-deformation curves and biomechanical parameters were compared between the study and control groups. Results When the muscle-tendon unit received eccentric cyclic loading to 112%, changes in all biomechanical parameters – except for the slope of the load-deformation curve – were not significant. In contrast, most parameters, including the slope of the load-deformation curve, peak load, deformation at peak load, total energy absorption, and energy absorption before peak load, significantly decreased after isokinetic eccentric cyclic loading to 120%. Conclusion We found a threshold for eccentrically induced injury of the rabbit triceps surae muscle at between 12% and 20% strain, which is within the physiologic excursion of the muscle-tendon units. Our study provided evidence that eccentric exercise may induce changes in the biomechanical properties of skeletal muscles, even within the physiologic range of the excursion of the muscle-tendon unit. PMID:17711591

  15. Evidence of imbalanced adaptation between muscle and tendon in adolescent athletes.

    PubMed

    Mersmann, F; Bohm, S; Schroll, A; Boeth, H; Duda, G; Arampatzis, A

    2014-08-01

    Adolescence may be regarded as a critical phase of tissue plasticity in young growing athletes, as the adaptation process of muscle-tendon unit is affected by both environmental mechanical stimuli and maturation. The present study investigated potential imbalances of knee extensor muscle strength and patellar tendon properties in adolescent compared with middle-aged athletes featuring long-term musculotendinous adaptations. Nineteen adolescent elite volleyball athletes [(A), 15.9 ± 0.6 years] and 18 middle-aged competitively active former elite volleyball athletes [(MA), 46.9 ± 0.6 years] participated in magnetic resonance imaging and ultrasound-dynamometry sessions to determine quadriceps femoris muscle strength, vastus lateralis morphology and patellar tendon mechanical and morphological properties. There was no significant age effect on the physiological cross-sectional area of the vastus lateralis and maximum knee extension moment (P > 0.05) during voluntary isometric contractions. However, the patellar tendon cross-sectional area was significantly smaller (A: 107.4 ± 27.5 mm(2) ; MA: 121.7 ± 39.8 mm(2) ) and the tendon stress during the maximal contractions was significantly higher in adolescent compared with the middle-aged athletes (A: 50.0 ± 10.1 MPa; MA: 40.0 ± 9.5 MPa). These findings provide evidence of an imbalanced development of muscle strength and tendon mechanical and morphological properties in adolescent athletes, which may have implications for the risk of tendon overuse injuries.

  16. Exercise protocol induces muscle, tendon, and bone adaptations in the rat shoulder

    PubMed Central

    Rooney, Sarah Ilkhanipour; Loro, Emanuele; Sarver, Joseph J.; Peltz, Cathryn D.; Hast, Michael W.; Tseng, Wei-Ju; Kuntz, Andrew F.; Liu, X. Sherry; Khurana, Tejvir S.; Soslowsky, Louis J.

    2014-01-01

    Summary Background: a rat model of supraspinatus overuse has suggested mechanisms governing tendon degeneration; however, delineating which changes are pathologic or simply physiologic adaptations to increased loading remains a question. The objective of this study was to develop and characterize a rat exercise model that induces systemic and local shoulder adaptations without mechanical injury to the supraspinatus tendon. Methods: exercise rats completed a treadmill training protocol for 12 weeks. Body, fat pad, and heart weights were determined. Supraspinatus tendon collagen content, cross-sectional area, and mechanical properties were measured. Supraspinatus muscle cross-sectional area, weight, and the expression of mitochondrial oxidative phosphorylation (OXPHOS) proteins were measured. Humeri were analyzed with μCT and mechanically tested. Results: exercise decreased fat pad mass. Supraspinatus muscle hypertrophied and had increased OXPHOS proteins. Humerus trabecular bone had increased anisotropic orientation, and cortical bone showed increased bone and tissue mineral density. Importantly, the supraspinatus tendon did not have diminished mechanical properties, indicating that this protocol was not injurious to the tendon. Conclusion: this study establishes the first rat exercise protocol that induces adaptations in the shoulder. Future research can use this as a comparison model to study how the supraspinatus tendon adapts to loading and undergoes degeneration with overuse. PMID:25767777

  17. Allograft anterior cruciate ligament reconstruction in patients younger than 30 years: a matched-pair comparison of bone-patellar tendon-bone and tibialis anterior.

    PubMed

    O'Brien, Daniel F; Kraeutler, Matthew J; Koyonos, Loukas; Flato, Russell R; Ciccotti, Michael G; Cohen, Steven B

    2014-03-01

    We conducted a study to compare patient-reported outcomes and graft-rupture rates of bone-patellar tendon-bone (BPTB) and tibialis anterior (TA) allograft primary anterior cruciate ligament (ACL) reconstruction in patients younger than 30 years. Patients were retrospectively identified as having undergone ACL reconstruction with either a BPTB (n = 20) or a TA (n = 20) allograft. Each patient in the BPTB group was matched to a patient in the TA group based on sex, age at time of surgery, height, weight, and preoperative activity level. The Lysholm Knee Scoring Scale and the International Knee Documentation Committee (IKDC) Subjective Knee Evaluation Form were administered at a minimum of 1 year after surgery. Mean Lysholm scores were 92.9 (BPTB) and 93.0 (TA), and mean IKDC scores were 92.6 (BPTB) and 90.3 (TA). The differences were not statistically significant. Overall graft-rupture rates for the study period were 4.7% (BPTB) and 1.9% (TA) (P = .18). There was no statistically significant difference in patient-rated outcomes and graft-rupture rates between BPTB and TA allografts for ACL reconstruction at a minimum of 1 year after surgery. Future research efforts should focus on mid- and long-term follow-up and objective outcomes.

  18. Control of position and movement is simplified by combined muscle spindle and Golgi tendon organ feedback.

    PubMed

    Kistemaker, Dinant A; Van Soest, Arthur J Knoek; Wong, Jeremy D; Kurtzer, Isaac; Gribble, Paul L

    2013-02-01

    Whereas muscle spindles play a prominent role in current theories of human motor control, Golgi tendon organs (GTO) and their associated tendons are often neglected. This is surprising since there is ample evidence that both tendons and GTOs contribute importantly to neuromusculoskeletal dynamics. Using detailed musculoskeletal models, we provide evidence that simple feedback using muscle spindles alone results in very poor control of joint position and movement since muscle spindles cannot sense changes in tendon length that occur with changes in muscle force. We propose that a combination of spindle and GTO afferents can provide an estimate of muscle-tendon complex length, which can be effectively used for low-level feedback during both postural and movement tasks. The feasibility of the proposed scheme was tested using detailed musculoskeletal models of the human arm. Responses to transient and static perturbations were simulated using a 1-degree-of-freedom (DOF) model of the arm and showed that the combined feedback enabled the system to respond faster, reach steady state faster, and achieve smaller static position errors. Finally, we incorporated the proposed scheme in an optimally controlled 2-DOF model of the arm for fast point-to-point shoulder and elbow movements. Simulations showed that the proposed feedback could be easily incorporated in the optimal control framework without complicating the computation of the optimal control solution, yet greatly enhancing the system's response to perturbations. The theoretical analyses in this study might furthermore provide insight about the strong physiological couplings found between muscle spindle and GTO afferents in the human nervous system.

  19. Calf muscle-tendon properties and postural balance in old age.

    PubMed

    Onambele, Gladys L; Narici, Marco V; Maganaris, Constantinos N

    2006-06-01

    We tested the hypothesis that compromised postural balance in older subjects is associated with changes in calf muscle-tendon physiological and mechanical properties. Trial duration and center of pressure (COP) displacements were measured in 24 younger (aged 24+/-1 yr), 10 middle-aged (aged 46+/-1 yr), and 36 older (aged 68+/-1 yr) healthy subjects under varying levels of postural difficulty. Muscle-tendon characteristics were assessed by dynamometry, twitch superimposition, and ultrasonography. In tandem and single-leg stances, trial duration decreased (Muscle strength, size, activation capacity, and tendon mechanical properties decreased with age by 55, 13, 13, and 36-48%, respectively (P<0.05). Regressions with these parameters and balance indexes were significant (P<0.05) for single-leg and tandem (0.69muscle-tendon characteristics may explain the majority of the variance in balance performance during tasks more difficult than habitual bipedal stance.

  20. ‘Serious thigh muscle strains’: beware the intramuscular tendon which plays an important role in difficult hamstring and quadriceps muscle strains

    PubMed Central

    Brukner, Peter; Connell, David

    2016-01-01

    Why do some hamstring and quadriceps strains take much longer to repair than others? Which injuries are more prone to recurrence? Intramuscular tendon injuries have received little attention as an element in ‘muscle strain’. In thigh muscles, such as rectus femoris and biceps femoris, the attached tendon extends for a significant distance within the muscle belly. While the pathology of most muscle injures occurs at a musculotendinous junction, at first glance the athlete appears to report pain within a muscle belly. In addition to the musculotendinous injury being a site of pathology, the intramuscular tendon itself is occasionally injured. These injuries have a variety of appearances on MRIs. There is some evidence that these injuries require a prolonged rehabilitation time and may have higher recurrence rates. Therefore, it is important to recognise the tendon component of a thigh ‘muscle strain’. PMID:26519522

  1. Modulatory effect of gastric pentadecapeptide BPC 157 on angiogenesis in muscle and tendon healing.

    PubMed

    Brcic, L; Brcic, I; Staresinic, M; Novinscak, T; Sikiric, P; Seiwerth, S

    2009-12-01

    Angiogenesis is a natural and complex process controlled by angiogenic and angiostatic molecules, with a central role in healing process. One of the most important modulating factors in angiogenesis is the vascular endothelial growth factor (VEGF). Pentadecapeptide BPC 157 promotes healing demonstrating particular angiogenic/angiomodulatory potential. We correlated the angiogenic effect of BPC 157 with VEGF expression using in vitro (cell culture) and in vivo (crushed muscle and transected muscle and tendon) models. Results revealed that there is no direct angiogenic effect of BPC 157 on cell cultures. On the other hand, immunohistochemical analysis of muscle and tendon healing using VEGF, CD34 and FVIII antibodies showed adequately modulated angiogenesis in BPC 157 treated animals, resulting in a more adequate healing. Therefore the angiogenic potential of BPC 157 seems to be closely related to the healing process in vivo with BPC 157 stimulating angiogenesis by up-regulating VEGF expression.

  2. Modulatory effect of gastric pentadecapeptide BPC 157 on angiogenesis in muscle and tendon healing.

    PubMed

    Brcic, L; Brcic, I; Staresinic, M; Novinscak, T; Sikiric, P; Seiwerth, S

    2009-12-01

    Angiogenesis is a natural and complex process controlled by angiogenic and angiostatic molecules, with a central role in healing process. One of the most important modulating factors in angiogenesis is the vascular endothelial growth factor (VEGF). Pentadecapeptide BPC 157 promotes healing demonstrating particular angiogenic/angiomodulatory potential. We correlated the angiogenic effect of BPC 157 with VEGF expression using in vitro (cell culture) and in vivo (crushed muscle and transected muscle and tendon) models. Results revealed that there is no direct angiogenic effect of BPC 157 on cell cultures. On the other hand, immunohistochemical analysis of muscle and tendon healing using VEGF, CD34 and FVIII antibodies showed adequately modulated angiogenesis in BPC 157 treated animals, resulting in a more adequate healing. Therefore the angiogenic potential of BPC 157 seems to be closely related to the healing process in vivo with BPC 157 stimulating angiogenesis by up-regulating VEGF expression. PMID:20388964

  3. Fascicle-tendon behavior of the gastrocnemius and soleus muscles during ankle bending exercise at different movement frequencies.

    PubMed

    Sakuma, Jun; Kanehisa, Hiroaki; Yanai, Toshimasa; Fukunaga, Tetsuo; Kawakami, Yasuo

    2012-03-01

    The present study investigated the effect of movement frequencies on the behavior of fascicles and tendons of synergistic muscles. Seven male subjects performed ankle bending (calf-raise) exercises at four movement frequencies (1.33, 1.67, 1.84, and 2.00 Hz), performed with an identical range of ankle joint motion. The fascicle and tendon behavior of medial gastrocnemius (MG) and soleus (SOL) was measured by ultrasonography while kinematic and kinetic parameters of the ankle were recorded. The torque of ankle joint was larger at higher exercise frequencies. The length change of muscle decreased and that of tendon increased at higher frequencies both for MG and for SOL, with no significant inter-muscle differences in the relative changes of muscle or tendon lengths to that of MTU. Changes of pennation angles and electromyographic activities as a function of movement frequency were also comparable for MG and SOL. These results suggest that under a stretch-shortening cycle action, the muscle-tendon interaction is altered by the movement frequency toward greater use of tendon elastic energy to provide greater MTU power at a higher frequency. Results also suggest that the movement frequency dependence of fascicle and tendon behavior is comparable between MG and SOL.

  4. Modeling Implantable Passive Mechanisms for Modifying the Transmission of Forces and Movements Between Muscle and Tendons.

    PubMed

    Homayouni, Taymaz; Underwood, Kelsey N; Beyer, Kamin C; Martin, Elon R; Allan, Christopher H; Balasubramanian, Ravi

    2015-09-01

    This paper explores the development of biomechanical models for evaluating a new class of passive mechanical implants for orthopedic surgery. The proposed implants take the form of passive engineered mechanisms, and will be used to improve the functional attachment of muscles to tendons and bone by modifying the transmission of forces and movement inside the body. Specifically, we present how two types of implantable mechanisms may be modeled in the open-source biomechanical software OpenSim. The first implant, which is proposed for hand tendon-transfer surgery, differentially distributes the forces and movement from one muscle across multiple tendons. The second implant, which is proposed for knee-replacement surgery, scales up the forces applied to the knee joint by the quadriceps muscle. This paper's key innovation is that such mechanisms have never been considered before in biomechanical simulation modeling and in surgery. When compared with joint function enabled by the current surgical practice of using sutures to make the attachment, biomechanical simulations show that the surgery with 1) the differential mechanism (tendon network) implant improves the fingers' ability to passively adapt to an object's shape significantly during grasping tasks (2.74× as measured by the extent of finger flexion) for the same muscle force, and 2) the force-scaling implant increases knee-joint torque by 84% for the same muscle force. The critical significance of this study is to provide a methodology for the design and inclusion of the implants into biomechanical models and validating the improvement in joint function they enable when compared with current surgical practice.

  5. A model of the human triceps surae muscle-tendon complex applied to jumping.

    PubMed

    Bobbert, M F; Huijing, P A; van Ingen Schenau, G J

    1986-01-01

    The purpose of this study was to gain more insight into the behavior of the muscle-tendon complex of human m. triceps surae in jumping. During one-legged vertical jumps of ten subjects ground reaction forces as well as cinematographic data were registered, and electromyograms were recorded from m. soleus and m. gastrocnemius. A model was developed of m. triceps surae, incorporating assumptions concerning dimensions, architecture, force-length and force-velocity relationships of muscle fibers, as well as assumptions concerning dimensions and elastic behavior of tendinous tissue in series with the muscle fibers. The velocity with which origin approaches insertion (V OI) was calculated for m. soleus and m. gastrocnemius using cine film data, and served as input of the model. During the last part of the push-off phase EMG-levels were found to be more or less constant, V OI of m. soleus and m. gastrocnemius rapidly increased, and the plantar flexing moment obtained by solving equations concerning a free body diagram of the foot rapidly declined. A similar decline was observed in the plantar flexing moment obtained by multiplying force calculated with help of the model by estimated moment arm at the ankle. As a result of the decline of exerted force tendon length decreases. According to the model the shortening velocity of tendon reaches higher values than that of muscle fibers. The results of a kinetic analysis demonstrate that during the last part of the push-off phase a combination of high angular velocities with relatively large plantar flexing moments is required. It is concluded that without a compliant tendon m. triceps surae would not be able to satisfy this requirement. PMID:3793737

  6. Extensor tendon ruptures after total knee arthroplasty.

    PubMed

    Bonnin, M; Lustig, S; Huten, D

    2016-02-01

    Extensor tendon rupture is a rare but serious complication after total knee arthroplasty (TKA) that impairs active knee extension, thereby severely affecting knee function. Surgery is usually required. Surgical options range from simple suturing to allograft reconstruction of the entire extensor mechanism and include intermediate methods such as reconstruction using neighbouring tendons or muscles, synthetic ligament implantation, and partial allograft repair. Simple suturing carries a high failure rate and should therefore be routinely combined with tissue augmentation using a neighbouring tendon or a synthetic ligament. After allograft reconstruction, outcomes are variable and long-term complications common. Salvage procedures for managing the most severe cases after allograft failure involve reconstruction using gastrocnemius or vastus flaps. Regardless of the technique used, suturing must be performed under tension, with the knee fully extended, and rehabilitation must be conducted with great caution. Weaknesses of available case-series studies include small sample sizes, heterogeneity, and inadequate follow-up duration. All treatment options are associated with substantial failure rates. The patient should be informed of this fact and plans made for a salvage option. Here, the main techniques and their outcomes are discussed, and a therapeutic strategy is suggested.

  7. A non-signaling role of Robo2 in tendons is essential for Slit processing and muscle patterning.

    PubMed

    Ordan, Elly; Volk, Talila

    2015-10-15

    Coordinated locomotion of an organism relies on the development of proper musculoskeletal connections. In Drosophila, the Slit-Robo signaling pathway guides muscles to tendons. Here, we show that the Slit receptor Roundabout 2 (Robo2) plays a non-cell-autonomous role in directing muscles to their corresponding tendons. Robo2 is expressed by tendons, and its non-signaling activity in these cells promotes Slit cleavage, producing a cleaved Slit N-terminal guidance signal that provides short-range signaling into muscles. Consistently, robo2 mutant embryos exhibited a muscle phenotype similar to that of slit, which could not be rescued by muscle-specific Robo2 expression but rather by ectodermally derived Robo2. Alternatively, this muscle phenotype could be induced by tendon-specific robo2 RNAi. We further show that membrane immobilization of Slit or its N-terminal cleaved form (Slit-N) on tendons bypasses the functional requirement for Robo2 in tendons, verifying that the major role of Robo2 is to promote the association of Slit with the tendon cell membrane. Slit-N tends to oligomerize whereas full-length uncleavable Slit does not. It is therefore proposed that Slit-N oligomers, produced at the tendon membrane by Robo2, signal to the approaching muscle by combined Robo1 and Robo3 activity. These findings establish a Robo2-mediated mechanism, independent of signaling, that is essential to limiting Slit distribution and which might be relevant to the regulation of Slit-mediated short-range signaling in additional systems.

  8. Expression of collagen and related growth factors in rat tendon and skeletal muscle in response to specific contraction types.

    PubMed

    Heinemeier, K M; Olesen, J L; Haddad, F; Langberg, H; Kjaer, M; Baldwin, K M; Schjerling, P

    2007-08-01

    Acute exercise induces collagen synthesis in both tendon and muscle, indicating an adaptive response in the connective tissue of the muscle-tendon unit. However, the mechanisms of this adaptation, potentially involving collagen-inducing growth factors (such as transforming growth factor-beta-1 (TGF-beta-1)), as well as enzymes related to collagen processing, are not clear. Furthermore, possible differential effects of specific contraction types on collagen regulation have not been investigated. Female Sprague-Dawley rats were subjected to 4 days of concentric, eccentric or isometric training (n = 7-9 per group) of the medial gastrocnemius, by stimulation of the sciatic nerve. RNA was extracted from medial gastrocnemius and Achilles tendon tissue 24 h after the last training bout, and mRNA levels for collagens I and III, TGF-beta-1, connective tissue growth factor (CTGF), lysyl oxidase (LOX), metalloproteinases (MMP-2 and -9) and their inhibitors (TIMP-1 and 2) were measured by Northern blotting and/or real-time PCR. In tendon, expression of TGF-beta-1 and collagens I and III (but not CTGF) increased in response to all types of training. Similarly, enzymes/factors involved in collagen processing were induced in tendon, especially LOX (up to 37-fold), which could indicate a loading-induced increase in cross-linking of tendon collagen. In skeletal muscle, a similar regulation of gene expression was observed, but in contrast to the tendon response, the effect of eccentric training was significantly greater than the effect of concentric training on the expression of several transcripts. In conclusion, the study supports an involvement of TGF-beta-1 in loading-induced collagen synthesis in the muscle-tendon unit and importantly, it indicates that muscle tissue is more sensitive than tendon to the specific mechanical stimulus.

  9. Replacement of the anterior cruciate ligament of the knee with deep frozen bone-tendon-bone allografts.

    PubMed

    Than, P; Bálint, L; Domán, I; Szabó, G

    1999-01-01

    Surgical treatment of the torn anterior cruciate ligament (ACL) and consequent knee instability showed great development over the last decade. Arthroscopic techniques and the use of different allogenic tissues became a routine. Between 1995 and 1998, 31 knees in 30 patients underwent ACL reconstruction of the knee with fresh-frozen allografts at the Department of Orthopedics, Medical University of Pécs, Hungary. The operations were performed with arthroscopic technique. This paper retrospectively assesses the outcomes with an average follow up of 28 months, which showed good results in most of the cases. The authors reviewed the literature emphasizing advantages and disadvantages of the method with special interest to possible complications resulting from the use of allografts: graft rejection, graft re-rupture, transmission of infection and synovitis evoked by immune response.

  10. Replacement of the anterior cruciate ligament of the knee with deep frozen bone-tendon-bone allografts.

    PubMed

    Than, P; Bálint, L; Domán, I; Szabó, G

    1999-01-01

    Surgical treatment of the torn anterior cruciate ligament (ACL) and consequent knee instability showed great development over the last decade. Arthroscopic techniques and the use of different allogenic tissues became a routine. Between 1995 and 1998, 31 knees in 30 patients underwent ACL reconstruction of the knee with fresh-frozen allografts at the Department of Orthopedics, Medical University of Pécs, Hungary. The operations were performed with arthroscopic technique. This paper retrospectively assesses the outcomes with an average follow up of 28 months, which showed good results in most of the cases. The authors reviewed the literature emphasizing advantages and disadvantages of the method with special interest to possible complications resulting from the use of allografts: graft rejection, graft re-rupture, transmission of infection and synovitis evoked by immune response. PMID:10853785

  11. 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.

  12. Morphometrics of the Anterior Belly and Intermediate Tendon of the Digastric Muscle: Sexual Dimorphism and Implications for Surgery.

    PubMed

    Zdilla, Matthew J; Pancake, Alex R; Lambert, H Wayne

    2016-07-01

    The anterior belly of the digastric muscle (ABDM) is important in a variety of surgeries including submental lipectomy, rhytidectomy, alteration of the cervicomental angle via muscle resection, the "digastric corset" procedure for submental rejuvenation, the submental artery flap, and reanimation of the mouth after facial nerve palsy. Despite its clinical significance, little information exists regarding the morphometrics of the ABDM or its associated intermediate tendon. This study analyzed a total of 35 intact ABDMs and 43 intact intermediate tendons from 23 cadavers. Measurements were taken of the following parameters: muscle belly area, muscle belly length, intermediate tendon length, and intermediate tendon width at mid-tendon. Normative descriptive statistics are included within the report. Males were found to have significantly longer left-sided muscle bellies than right-sided bellies from males (U = 23.0; P = 0.044), left-sided bellies from females (U = 19.0; P = 0.020), and right-sided bellies from females (U = 12.0; P = 0.035). The morphometry, including sexual dimorphism, presented in this report can aid in the surgical planning and execution of numerous operations performed in head and neck, especially digastric muscle transfer surgery. PMID:27258716

  13. Changes in Indirect Markers of Muscle Damage and Tendons After Daily Drop Jumping Exercise with Rapid Load Increase.

    PubMed

    Paleckis, Vidas; Mickevičius, Mantas; Snieckus, Audrius; Streckis, Vytautas; Pääsuke, Mati; Rutkauskas, Saulius; Steponavičiūtė, Rasa; Skurvydas, Albertas; Kamandulis, Sigitas

    2015-12-01

    The aim of this study was to assess changes in indirect markers of muscle damage and type I collagen degradation, as well as, patellar and Achilles tendon morphological differences during nine daily drop-jumps sessions with constant load alternated with rapid increases in load to test the hypothesis that frequent drop-jump training results in negative muscular and tendon adaptation. Young men (n = 9) performed daily drop jump workouts with progression every 3 days in terms of number of jumps, platform height and squat amplitude. Voluntary and electrically evoked knee extensor torque, muscle soreness, blood plasma creatine kinase (CK) activity and carboxyterminal cross-linked telopeptide (ICTP), patellar and Achilles tendon thickness and cross-sectional area (CSA) were assessed at different time points during the training period and again on days 1, 3, 10 and 17 after the training. The findings were as follows: (1) steady decline in maximal muscle strength with major recovery within 24 hours after the first six daily training sessions; (2) larger decline in electrically induced muscle torque and prolonged recovery during last three training sessions; (3) increase in patellar and Achilles tendons CSA without change in thickness towards the end of training period; (4) increase in jump height but not in muscle strength after whole training period. Our findings suggest that frequent drop-jump sessions with constant load alternated with rapid increases in load do not induce severe muscle damage or major changes in tendons, nonetheless, this type of loading is not advisable for muscle strength improvement. Key pointsFrequent drop jump training induces activation mode dependent muscle torque depression late in the training period.No significant changes in the thickness of patellar and Achilles tendons are observed during frequent training, while CSA increases towards the end of training period.Longitudinal effect for jump height but not for muscle strength is evident after

  14. Surgical Intervention for Masticatory Muscle Tendon-Aponeurosis Hyperplasia Based on the Diagnosis Using the Four-Dimensional Muscle Model

    PubMed Central

    Nakaoka, Kazutoshi; Hamada, Yoshiki; Nakatani, Hayaki; Shigeta, Yuko; Hirai, Shinya; Ikawa, Tomoko; Mishima, Akira; Ogawa, Takumi

    2015-01-01

    Objectives: The surgical target of Masticatory muscle tendon-aponeurosis hyperplasia (MMTAH) is the masseter or temporal muscle. In our clinic, the 4-dimentional muscle model (4DMM) has been used to decide if we should approach to the masseter or temporal muscle. The aim of this study is validate the clinical usefulness of 4DMM on the basis of the surgical results. Methods: The 4DMM was constructed from the digital data of 3D-CT and 4-dimentional mandibular movements of the patients. It made us to able to visually observe the expansion rate of masticatory muscles at maximum mouth opening comparing to their length at closed mouth position. Fifteen patients were applied the 4DMM before the surgical treatment and 2 healthy volunteers were enrolled as control group. Results: The expansion rate of temporal muscle at the maximum mouth opening in the patient group was significantly less than that in the control group (P < 0.05). On the other hand, the masseter muscles of all patients were expanded as same as the control group. Therefore the main cause of limitation of mouth-opening was suggested to be a contracture of the temporal muscle. Consequently, we performed successful bilateral coronoidectomy with no surgical intervention to the masseter muscles in all patients. Conclusion: The present 4DMM would be valuable modality to decide the target muscle of surgical treatment for patients with MMTAH. In this pathology, contracture of the temporal muscle seems to be main cause of limited mouth opening. PMID:26352365

  15. Force responses to controlled stretches of electrically stimulated human muscle-tendon complex.

    PubMed

    Cook, C S; McDonagh, M J

    1995-05-01

    Human first dorsal interosseus muscle was tetanized using percutaneous electrical stimulation. During the tetanus the muscle was subjected to constant velocity stretches. The stretch produced an enhancement of muscular force of up to 80% during the stretch. The size of the enhancement was dependent on both the amplitude and the velocity of the stretch. During an isometric hold phase after the stretch, the force decayed quickly for the first 100 ms and thereafter much more slowly, reaching a level 30% higher than the isometric force without pre-stretch. The force during this hold phase was dependent on amplitude of stretch but was independent of stretch velocity. The interaction of tendon elasticity and muscle fibre mechanics in producing these responses is discussed. Implications for normal human movements are also explored. PMID:7640012

  16. Muscle forces during locomotion in kangaroo rats: force platform and tendon buckle measurements compared.

    PubMed

    Biewener, A A; Blickhan, R; Perry, A K; Heglund, N C; Taylor, C R

    1988-07-01

    The muscle forces and stresses occurring during normal locomotor activity in kangaroo rats are compared with the peak isometric force developed by the same muscles in situ. Two methods were used simultaneously to determine the stresses (force/cross-sectional area) acting in the ankle extensors during steady-speed hopping and during jumps when animals were startled: a direct measurement using a force buckle surgically implanted around a tendon; and an indirect measurement using a force platform/ciné analysis technique. We obtained essentially the same values with the two techniques. We found that at slow speeds (0.7 m s-1) the ankle extensor muscles of kangaroo rats exerted 20% of the maximum isometric force developed when the muscles were stimulated via the tibial nerve. This increased to 53% at higher speeds (1.9 m s-1). At the animals's preferred hopping speed (1.5 m s-1), peak force was approximately 40% of maximum isometric force. In jumps when animals were startled, peak forces as high as 175% of the maximal elicited isometric force were recorded. These high forces always occurred when the muscles were being stretched. It appears that kangaroo rats utilize nearly the entire range of muscle force possible during normal locomotor events (i.e. up to 175% of maximum isometric force when muscles are stretched).

  17. Development of the deep flexor tendons and lumbricalis muscle in the hand and foot: a histological study using human mid-term foetuses.

    PubMed

    Cho, K H; Kim, J H; Ha, Y S; Murakami, G; Cho, B H; Abe, S

    2012-08-01

    To revisit foetal development of the deep flexor tendons of the hand and foot, we examined the paraffin-embedded histology of 20 mid-term foetuses at 8-15 weeks of estimated gestational age (35-118 mm crown-rump length or CRL). At 8-9 weeks, in front of the metacarpal bones, the flexor pollicis longus and flexor digitorum profundus (FDP) muscles provided a plate-like, common tendon from which the lumbricalis muscles originated. However, in the foot, we had no evidence of such a common tendon. The flexor pollicis tendon was separated from the common tendon at 9-10 weeks possibly due to mechanical stress from the laterally growing thumb. Notably, at the lumbricalis muscle origins at 10-12 weeks, the FDP and flexor digitorum longus tendons remained undifferentiated and the primitive tenocytes were dispersed from them. The dispersed cells seemed to develop into an interface tissue between the lumbricalis muscle fibre and the deep tendon. In 3 of 5 specimens at 15 weeks, we found an excess number of the FDP tendons (5-7) in the proximal side of the lumbricalis muscle origin. However, the excess tendons dispersed in the lumbricalis muscle origin. The development of the lumbricalis muscle origin might follow the tendon splitting for four fingers. However, conversely, we hypothesised that the developing lumbricalis muscles re-arranged the deep flexor tendons to provide a configuration of one deep tendon per one finger (or toe). The quadrates plantae muscle seemed not to contribute on the re-arrangement.

  18. Amontillado is required for Drosophila Slit processing and for tendon-mediated muscle patterning

    PubMed Central

    Ordan, Elly

    2016-01-01

    ABSTRACT Slit cleavage into N-terminal and C-terminal polypeptides is essential for restricting the range of Slit activity. Although the Slit cleavage site has been characterized previously and is evolutionally conserved, the identity of the protease that cleaves Slit remains elusive. Our previous analysis indicated that Slit cleavage is essential to immobilize the active Slit-N at the tendon cell surfaces, mediating the arrest of muscle elongation. In an attempt to identify the protease required for Slit cleavage we performed an RNAi-based assay in the ectoderm and followed the process of elongation of the lateral transverse muscles toward tendon cells. The screen led to the identification of the Drosophila homolog of pheromone convertase 2 (PC2), Amontillado (Amon), as an essential protease for Slit cleavage. Further analysis indicated that Slit mobility on SDS polyacrylamide gel electrophoresis (SDS-PAGE) is slightly up-shifted in amon mutants, and its conventional cleavage into the Slit-N and Slit-C polypeptides is attenuated. Consistent with the requirement for amon to promote Slit cleavage and membrane immobilization of Slit-N, the muscle phenotype of amon mutant embryos was rescued by co-expressing a membrane-bound form of full-length Slit lacking the cleavage site and knocked into the slit locus. The identification of a novel protease component essential for Slit processing may represent an additional regulatory step in the Slit signaling pathway. PMID:27628033

  19. Unconstrained muscle-tendon workloops indicate resonance tuning as a mechanism for elastic limb behavior during terrestrial locomotion.

    PubMed

    Robertson, Benjamin D; Sawicki, Gregory S

    2015-10-27

    In terrestrial locomotion, there is a missing link between observed spring-like limb mechanics and the physiological systems driving their emergence. Previous modeling and experimental studies of bouncing gait (e.g., walking, running, hopping) identified muscle-tendon interactions that cycle large amounts of energy in series tendon as a source of elastic limb behavior. The neural, biomechanical, and environmental origins of these tuned mechanics, however, have remained elusive. To examine the dynamic interplay between these factors, we developed an experimental platform comprised of a feedback-controlled servo-motor coupled to a biological muscle-tendon. Our novel motor controller mimicked in vivo inertial/gravitational loading experienced by muscles during terrestrial locomotion, and rhythmic patterns of muscle activation were applied via stimulation of intact nerve. This approach was based on classical workloop studies, but avoided predetermined patterns of muscle strain and activation-constraints not imposed during real-world locomotion. Our unconstrained approach to position control allowed observation of emergent muscle-tendon mechanics resulting from dynamic interaction of neural control, active muscle, and system material/inertial properties. This study demonstrated that, despite the complex nonlinear nature of musculotendon systems, cyclic muscle contractions at the passive natural frequency of the underlying biomechanical system yielded maximal forces and fractions of mechanical work recovered from previously stored elastic energy in series-compliant tissues. By matching movement frequency to the natural frequency of the passive biomechanical system (i.e., resonance tuning), muscle-tendon interactions resulting in spring-like behavior emerged naturally, without closed-loop neural control. This conceptual framework may explain the basis for elastic limb behavior during terrestrial locomotion. PMID:26460038

  20. Unconstrained muscle-tendon workloops indicate resonance tuning as a mechanism for elastic limb behavior during terrestrial locomotion.

    PubMed

    Robertson, Benjamin D; Sawicki, Gregory S

    2015-10-27

    In terrestrial locomotion, there is a missing link between observed spring-like limb mechanics and the physiological systems driving their emergence. Previous modeling and experimental studies of bouncing gait (e.g., walking, running, hopping) identified muscle-tendon interactions that cycle large amounts of energy in series tendon as a source of elastic limb behavior. The neural, biomechanical, and environmental origins of these tuned mechanics, however, have remained elusive. To examine the dynamic interplay between these factors, we developed an experimental platform comprised of a feedback-controlled servo-motor coupled to a biological muscle-tendon. Our novel motor controller mimicked in vivo inertial/gravitational loading experienced by muscles during terrestrial locomotion, and rhythmic patterns of muscle activation were applied via stimulation of intact nerve. This approach was based on classical workloop studies, but avoided predetermined patterns of muscle strain and activation-constraints not imposed during real-world locomotion. Our unconstrained approach to position control allowed observation of emergent muscle-tendon mechanics resulting from dynamic interaction of neural control, active muscle, and system material/inertial properties. This study demonstrated that, despite the complex nonlinear nature of musculotendon systems, cyclic muscle contractions at the passive natural frequency of the underlying biomechanical system yielded maximal forces and fractions of mechanical work recovered from previously stored elastic energy in series-compliant tissues. By matching movement frequency to the natural frequency of the passive biomechanical system (i.e., resonance tuning), muscle-tendon interactions resulting in spring-like behavior emerged naturally, without closed-loop neural control. This conceptual framework may explain the basis for elastic limb behavior during terrestrial locomotion.

  1. Unconstrained muscle-tendon workloops indicate resonance tuning as a mechanism for elastic limb behavior during terrestrial locomotion

    PubMed Central

    Robertson, Benjamin D.; Sawicki, Gregory S.

    2015-01-01

    In terrestrial locomotion, there is a missing link between observed spring-like limb mechanics and the physiological systems driving their emergence. Previous modeling and experimental studies of bouncing gait (e.g., walking, running, hopping) identified muscle-tendon interactions that cycle large amounts of energy in series tendon as a source of elastic limb behavior. The neural, biomechanical, and environmental origins of these tuned mechanics, however, have remained elusive. To examine the dynamic interplay between these factors, we developed an experimental platform comprised of a feedback-controlled servo-motor coupled to a biological muscle-tendon. Our novel motor controller mimicked in vivo inertial/gravitational loading experienced by muscles during terrestrial locomotion, and rhythmic patterns of muscle activation were applied via stimulation of intact nerve. This approach was based on classical workloop studies, but avoided predetermined patterns of muscle strain and activation—constraints not imposed during real-world locomotion. Our unconstrained approach to position control allowed observation of emergent muscle-tendon mechanics resulting from dynamic interaction of neural control, active muscle, and system material/inertial properties. This study demonstrated that, despite the complex nonlinear nature of musculotendon systems, cyclic muscle contractions at the passive natural frequency of the underlying biomechanical system yielded maximal forces and fractions of mechanical work recovered from previously stored elastic energy in series-compliant tissues. By matching movement frequency to the natural frequency of the passive biomechanical system (i.e., resonance tuning), muscle-tendon interactions resulting in spring-like behavior emerged naturally, without closed-loop neural control. This conceptual framework may explain the basis for elastic limb behavior during terrestrial locomotion. PMID:26460038

  2. An endoscopic approach to longitudinal structures including muscle flaps and vein, tendon, and nerve grafts.

    PubMed

    Hallock, Geoffrey G; Rice, David C

    2008-02-01

    Anatomically favorable structures that have a longitudinal orientation are particularly amenable to endoscopic harvest. Typically, only a single portal is necessary for access, and an optical cavity can be maintained using a mechanical retraction device. As with all minimal invasive surgery, this can still allow rapid and often a safer tissue harvest with diminished morbidity, especially with respect to wound healing and non-aesthetic scar formation. Many plastic surgery applications have already been described facilitated by the endoscopic harvest of vein, tendon, and nerve grafts, as well as certain local or free muscle flaps.

  3. Altered Protein Composition and Gene Expression in Strabismic Human Extraocular Muscles and Tendons

    PubMed Central

    Agarwal, Andrea B.; Feng, Cheng-Yuan; Altick, Amy L.; Quilici, David R.; Wen, Dan; Johnson, L. Alan; von Bartheld, Christopher S.

    2016-01-01

    Purpose To determine whether structural protein composition and expression of key regulatory genes are altered in strabismic human extraocular muscles. Methods Samples from strabismic horizontal extraocular muscles were obtained during strabismus surgery and compared with normal muscles from organ donors. We used proteomics, standard and customized PCR arrays, and microarrays to identify changes in major structural proteins and changes in gene expression. We focused on muscle and connective tissue and its control by enzymes, growth factors, and cytokines. Results Strabismic muscles showed downregulation of myosins, tropomyosins, troponins, and titin. Expression of collagens and regulators of collagen synthesis and degradation, the collagenase matrix metalloproteinase (MMP)2 and its inhibitors, tissue inhibitor of metalloproteinase (TIMP)1 and TIMP2, was upregulated, along with tumor necrosis factor (TNF), TNF receptors, and connective tissue growth factor (CTGF), as well as proteoglycans. Growth factors controlling extracellular matrix (ECM) were also upregulated. Among 410 signaling genes examined by PCR arrays, molecules with downregulation in the strabismic phenotype included GDNF, NRG1, and PAX7; CTGF, CXCR4, NPY1R, TNF, NTRK1, and NTRK2 were upregulated. Signaling molecules known to control extraocular muscle plasticity were predominantly expressed in the tendon rather than the muscle component. The two horizontal muscles, medial and lateral rectus, displayed similar changes in protein and gene expression, and no obvious effect of age. Conclusions Quantification of proteins and gene expression showed significant differences in the composition of extraocular muscles of strabismic patients with respect to important motor proteins, elements of the ECM, and connective tissue. Therefore, our study supports the emerging view that the molecular composition of strabismic muscles is substantially altered. PMID:27768799

  4. The influence of loading intensity on muscle-tendon unit behavior during maximal knee extensor stretch shortening cycle exercise.

    PubMed

    Earp, Jacob E; Newton, Robert U; Cormie, Prue; Blazevich, Anthony J

    2014-01-01

    Tendon stiffness increases as the magnitude and rate of loading increases, according to its viscoelastic properties. Thus, under some loading conditions tendons should become exceptionally stiff and act almost as rigid force transducers. Nonetheless, observations of tendon behavior during multi-joint sprinting and jumping tasks have shown that tendon strain increases whilst muscle strain decreases as the loading intensity increases. The purpose of the current study was to examine the influence of external loading intensity on muscle-tendon unit (MTU) behavior during a high-speed single-joint, stretch-shortening cycle (SSC) knee extension task. Eighteen men (n = 9) and women (n = 9) performed single-leg, maximum intensity SSC knee extensions at loads of 20, 60 and 90% of their one repetition maximum. Vastus lateralis fascicle length (L(f)) and velocity (v(f)) as well as MTU (L(MTU)) and tendinous tissue (L(t)) length were measured using high-speed ultrasonography (96 Hz). Patellar tendon force (F(t)) and rate of force development (RFDt) were estimated using inverse dynamics. Results showed that as loading intensity increased, concentric joint velocity and shortening v f decreased whilst F t and RFDt increased, but no significant differences were observed in eccentric joint velocity or peak L(MTU) or L(f). In addition, the tendon lengthened significantly less at the end of the eccentric phase at heavier loads. This is the first observation that tendon strain decreases significantly during a SSC movement as loading intensity increases in vivo, resulting in a shift in the tendon acting as a power amplifier at light loads to a more rigid force transducer at heavy loads.

  5. Prostaglandin synthetase and prostacyclin synthetase in mature rat skeletal muscles: immunohistochemical localisation to arterioles, tendons and connective tissues.

    PubMed Central

    McLennan, I S; Macdonald, R E

    1991-01-01

    Mature skeletal muscles produce appreciable quantities of prostacyclin (PGI2) and smaller amounts of PGF2 alpha and PGE2, but the sources of these prostaglandins within skeletal muscle are unknown. Monoclonal antibodies to prostaglandin synthetase and prostacyclin synthetase were used to determine which muscle cells produce prostaglandins. The antibody to prostacyclin synthetase stained the tendon, fascia, epimysium and the arteries leading to the muscles. The endothelia of arterioles were also stained in the tibialis anterior and cremaster but not in the soleus muscles. Only trace levels of immunoreactivity were observed with the antibody to prostaglandin synthetase in normal muscles. However, immunoreactivity was observed in the muscles of rats that had been pretreated with aspirin, a drug that inhibits and stabilises prostaglandin synthetase. In muscles of the aspirin-treated rats, all cell types that were stained by the antiprostacyclin synthetase also reacted weakly with the antibody to prostaglandin synthetase. In addition, some cells in the endomysium were strongly stained with the antiprostaglandin synthetase but not with the antiprostacyclin synthetase. We conclude that (1) at least one aspect of the regulation of blood flow in the microcirculation of slow muscles is different from that of fast muscles, (2) that the tendon and connective tissue is the major source of PGI2 in mature skeletal muscles, and (3) that the prostaglandin-dependent effects of insulin and some other stimuli on skeletal muscle may be mediated by the muscle's arterioles or connective tissue. Images Fig. 1 Fig. 2 Fig. 3 PMID:1810931

  6. Effects of repeated ankle stretching on calf muscle-tendon and ankle biomechanical properties in stroke survivors

    PubMed Central

    Gao, Fan; Ren, Yupeng; Roth, Elliot J.; Harvey, Richard; Zhang, Li-Qun

    2011-01-01

    Background The objective of this study was to investigate changes in active and passive biomechanical properties of the calf muscle-tendon unit induced by controlled ankle stretching in stroke survivors. Methods Ten stroke survivors with ankle spasticity/contracture and ten healthy control subjects received intervention of 60-min ankle stretching. Joint biomechanical properties including resistance torque, stiffness and index of hysteresis were evaluated pre- and post-intervention. Achilles tendon length was measured using ultrasonography. The force output of the triceps surae muscles was characterized via the torque-angle relationship, by stimulating the calf muscles at a controlled intensity across different ankle positions. Findings Compared to healthy controls, the ankle position corresponding to the peak torque of the stroke survivors was shifted towards plantar flexion (P<0.001). Stroke survivors showed significantly higher resistance torques and joint stiffness (P<0.05), and these higher resistances were reduced significantly after the stretching intervention, especially in dorsiflexion (P = 0.013). Stretching significantly improved the force output of the impaired calf muscles in stroke survivors under matched stimulations (P<0.05). Ankle range of motion was also increased by stretching (P<0.001). Interpretation At the joint level, repeated stretching loosened the ankle joint with increased passive joint range of motion and decreased joint stiffness. At the muscle-tendon level, repeated stretching improved calf muscle force output, which might be associated with decreased muscle fascicle stiffness, increased fascicle length and shortening of the Achilles tendon. The study provided evidence of improvement in muscle tendon properties through stretching intervention. PMID:21211873

  7. Enthesitis of the direct tendon of the rectus femoris muscle in a professional volleyball player: A case report.

    PubMed

    Bortolotto, C; Coscia, D R; Ferrozzi, G

    2011-06-01

    Enthesitis of the direct tendon of the rectus femoris muscle is a rare pathology which mainly affects professional athletes, and it is caused by overuse and repetitive microtrauma. Athletic jumping and kicking exert a great stress on the direct tendon of the rectus femoris muscle, and volleyball and football players are therefore most frequently affected. Enthesitis may occur suddenly causing pain and functional impairment possibly associated with partial or complete tendon injuries, or it may be a chronic condition causing non-specific clinical symptoms.We present the case of a professional volleyball player who felt a sudden pain in the left side of the groin area during a training session although she had suffered no accidental injury. The pain was associated with impaired ipsilateral limb function. Tendon rupture was suspected, and magnetic resonance imaging (MRI) was performed. MRI showed a lesion at the myotendinous junction associated with marked inhomogeneity of the direct tendon. Ultrasound (US) examination confirmed the presence of both lesions and allowed a more detailed study of the pathology.This is a typical case of enthesitis which confirms that MRI should be considered the examination of choice in hip pain, particularly when the patient is a professional athlete, thanks to its panoramic visualization. However, also US is an ideal imaging technique for evaluating tendon injuries thanks to its high spatial resolution, and it can therefore be used effectively as a second line of investigation.

  8. Host-Derived Smooth Muscle Cells Accumulate in Cardiac Allografts: Role of Inflammation and Monocyte Chemoattractant Protein 1

    PubMed Central

    Bojakowski, Krzysztof; Soin, Joanna; Nozynski, Jerzy; Zakliczynski, Michal; Gaciong, Zbigniew; Zembala, Marian; Söderberg-Nauclér, Cecilia

    2009-01-01

    Transplant arteriosclerosis is characterized by inflammation and intimal thickening caused by accumulation of smooth muscle cells (SMCs) both from donor and recipient. We assessed the relationship between clinical factors and the presence of host-derived SMCs in 124 myocardial biopsies from 26 consecutive patients who received hearts from opposite-sex donors. Clinical and demographic information was obtained from the patients' medical records. Host-derived SMCs accounted for 3.35±2.3% of cells in arterioles (range, 0.08–12.51%). As shown by linear regression analysis, an increased number of SMCs was associated with rejection grade (mean, 1.41±1.03, p = 0.034) and the number of leukocytes (19.1±12.7 per 20 high-power fields, p = 0.01). The accumulation of host-derived SMCs was associated with an increased number of leukocytes in the allografts. In vitro, monocyte chemoattractant protein 1 (MCP-1) released from leukocytes was crucial for SMC migration. After heart allotransplantion, mice treated with MCP-1-specific antibodies had significantly fewer host-derived SMCs in the grafts than mice treated with isotypic antibody controls. We conclude that the number of host-derived SMCs in human cardiac allografts is associated with the rejection grade and that MCP-1 may play pivotal role in recruiting host-derived SMCs into cardiac allografts. PMID:19142231

  9. Artificial muscles of dielectric elastomers attached to artificial tendons of functionalized carbon fibers

    NASA Astrophysics Data System (ADS)

    Ye, Zhihang; Faisal, Md. Shahnewaz Sabit; Asmatulu, Ramazan; Chen, Zheng

    2014-03-01

    Dielectric elastomers are soft actuation materials with promising applications in robotics and biomedical de- vices. In this paper, a bio-inspired artificial muscle actuator with artificial tendons is developed for robotic arm applications. The actuator uses dielectric elastomer as artificial muscle and functionalized carbon fibers as artificial tendons. A VHB 4910 tape is used as the dielectric elastomer and PDMS is used as the bonding material to mechanically connect the carbon fibers to the elastomer. Carbon fibers are highly popular for their high electrical conductivities, mechanical strengths, and bio-compatibilities. After the acid treatments for the functionalization of carbon fibers (500 nm - 10 μm), one end of carbon fibers is spread into the PDMS material, which provides enough bonding strength with other dielectric elastomers, while the other end is connected to a DC power supply. To characterize the actuation capability of the dielectric elastomer and electrical conductivity of carbon fibers, a diaphragm actuator is fabricated, where the carbon fibers are connected to the actuator. To test the mechanical bonding between PDMS and carbon fibers, specimens of PDMS bonded with carbon fibers are fabricated. Experiments have been conducted to verify the actuation capability of the dielectric elastomer and mechanical bonding of PDMS with carbon fibers. The energy efficiency of the dielectric elastomer increases as the load increases, which can reach above 50%. The mechanical bonding is strong enough for robotic arm applications.

  10. Fatigue and muscle-tendon stiffness after stretch-shortening cycle and isometric exercise.

    PubMed

    Toumi, Hechmi; Poumarat, Georges; Best, Thomas M; Martin, Alain; Fairclough, John; Benjamin, Mike

    2006-10-01

    The purpose of the present study was to compare vertical jump performance after 2 different fatigue protocols. In the first protocol, subjects performed consecutive sets of 10 repetitions of stretch-shortening cycle (SSC) contractions. In the second protocol, successive sets of 10 repetitions of isometric contractions were performed for 10 s with the knee at 90 degrees of flexion. The exercises were stopped when the subjects failed to reach 50% of their maximum voluntary isometric contractions. Maximal isometric force and maximal concentric power were assessed by performing supine leg presses, squat jumps, and drop jumps. Surface EMG was used to determine changes in muscle activation before and after fatigue. In both groups, the fatigue exercises reduced voluntary isometric force, maximal concentric power, and drop jump performance. Kinematic data showed a decrease in knee muscle-tendon stiffness accompanied by a lengthened ground contact time. EMG analysis showed that the squat and drop jumps were performed similarly before and after the fatigue exercise for both groups. Although it was expected that the stiffness would decrease more after SSC than after isometric fatigue (as a result of a greater alteration of the reflex sensitivity SSC), our results showed that both protocols had a similar effect on knee muscle stiffness during jumping exercises. Both fatigue protocols induced muscle fatigue, and the decrease in jump performance was linked to a decrease in the strength and stiffness of the knee extensor muscles. PMID:17111011

  11. Noninvasive ultrasonic monitoring of the mechanical properties of selected muscles and connected tendons

    NASA Astrophysics Data System (ADS)

    Zakir Hossain, M.; Grill, W.

    2012-04-01

    The force-length relation is one of the most important mechanical properties of skeletal muscular tissue. Due to the rather limited availability of non-invasive methods suitable to quantify the in-vivo biomechanical properties of activated human muscles and connected tendons, the quantification of the bio-mechanical properties is difficult. The measurement principle applied here is based on the detection of the dynamics of the muscle under observation by an ultrasonic caliper and monitoring of the externally present forces by a synchronously operated ultrasonic force sensor. The developed monitoring scheme is exemplified for gradual increasing voluntary isometric contraction (MVIC) of the gastrocnemius muscle up to maximum contraction, with the force sensor restricting the flexion of the joint. The temporal resolution for the monitoring is 0.01 s, relating to a monitoring rate of 100 Hz and is achieved with a spatial resolution concerning the observed lateral extension of the muscle of 0.01 mm. The employed low power, economic and non-intrusive detection scheme and respective instrumentation have the demonstrated potential to quantify the in-vivo hysteretic behavior of the observed force-length relation for MVIC of the human gastrocnemius muscle for the first time. The purpose of this study was to determine in-vivo the force-length relations for the human gastrocnemius and biceps muscles noninvasively by suitable experimental techniques with high temporal and spatial resolution concerning monitoring of the biomechanical relevant parameters involved in the dynamics of activated muscle. The data is collected and analyzed to derive quantitative information on force-length relations, essential for the analysis of muscle performance and interpretation by musculoskeletal models. The involved technologies are demonstrated and the respective results are presented and discussed.

  12. Dissection of a single rat muscle-tendon complex changes joint moments exerted by neighboring muscles: implications for invasive surgical interventions.

    PubMed

    Maas, Huub; Baan, Guus C; Huijing, Peter A

    2013-01-01

    The aim of this paper is to investigate mechanical functioning of a single skeletal muscle, active within a group of (previously) synergistic muscles. For this purpose, we assessed wrist angle-active moment characteristics exerted by a group of wrist flexion muscles in the rat for three conditions: (i) after resection of the upper arm skin; (ii) after subsequent distal tenotomy of flexor carpi ulnaris muscle (FCU); and (iii) after subsequent freeing of FCU distal tendon and muscle belly from surrounding tissues (MT dissection). Measurements were performed for a control group and for an experimental group after recovery (5 weeks) from tendon transfer of FCU to extensor carpi radialis (ECR) insertion. To assess if FCU tenotomy and MT dissection affects FCU contributions to wrist moments exclusively or also those of neighboring wrist flexion muscles, these data were compared to wrist angle-moment characteristics of selectively activated FCU. FCU tenotomy and MT dissection decreased wrist moments of the control group at all wrist angles tested, including also angles for which no or minimal wrist moments were measured when activating FCU exclusively. For the tendon transfer group, wrist flexion moment increased after FCU tenotomy, but to a greater extent than can be expected based on wrist extension moments exerted by selectively excited transferred FCU. We conclude that dissection of a single muscle in any surgical treatment does not only affect mechanical characteristics of the target muscle, but also those of other muscles within the same compartment. Our results demonstrate also that even after agonistic-to-antagonistic tendon transfer, mechanical interactions with previously synergistic muscles do remain present.

  13. Timing matters: tuning the mechanics of a muscle-tendon unit by adjusting stimulation phase during cyclic contractions.

    PubMed

    Sawicki, Gregory S; Robertson, Benjamin D; Azizi, Emanuel; Roberts, Thomas J

    2015-10-01

    A growing body of research on the mechanics and energetics of terrestrial locomotion has demonstrated that elastic elements acting in series with contracting muscle are critical components of sustained, stable and efficient gait. Far fewer studies have examined how the nervous system modulates muscle-tendon interaction dynamics to optimize 'tuning' or meet varying locomotor demands. To explore the fundamental neuromechanical rules that govern the interactions between series elastic elements (SEEs) and contractile elements (CEs) within a compliant muscle-tendon unit (MTU), we used a novel work loop approach that included implanted sonomicrometry crystals along muscle fascicles. This enabled us to decouple CE and SEE length trajectories when cyclic strain patterns were applied to an isolated plantaris MTU from the bullfrog (Lithobates catesbeianus). Using this approach, we demonstrate that the onset timing of muscle stimulation (i.e. stimulation phase) that involves a symmetrical MTU stretch-shorten cycle during active force production results in net zero mechanical power output, and maximal decoupling of CE and MTU length trajectories. We found it difficult to 'tune' the muscle-tendon system for strut-like isometric force production by adjusting stimulation phase only, as the zero power output condition involved significant positive and negative mechanical work by the CE. A simple neural mechanism - adjusting muscle stimulation phase - could shift an MTU from performing net zero to net positive (energy producing) or net negative (energy absorbing) mechanical work under conditions of changing locomotor demand. Finally, we show that modifications to the classical work loop paradigm better represent in vivo muscle-tendon function during locomotion.

  14. Training-induced changes in structural and mechanical properties of the patellar tendon are related to muscle hypertrophy but not to strength gains.

    PubMed

    Seynnes, O R; Erskine, R M; Maganaris, C N; Longo, S; Simoneau, E M; Grosset, J F; Narici, M V

    2009-08-01

    To obtain a better understanding of the adaptations of human tendon to chronic overloading, we examined the relationships between these adaptations and the changes in muscle structure and function. Fifteen healthy male subjects (20+/-2 yr) underwent 9 wk of knee extension resistance training. Patellar tendon stiffness and modulus were assessed with ultrasonography, and cross-sectional area (CSA) was determined along the entire length of the tendon by using magnetic resonance imaging. In the quadriceps muscles, architecture and volume measurements were combined to obtain physiological CSA (PCSA), and maximal isometric force was recorded. Following training, muscle force and PCSA increased by 31% (P<0.0001) and 7% (P<0.01), respectively. Tendon CSA increased regionally at 20-30%, 60%, and 90-100% of tendon length (5-6%; P<0.05), and tendon stiffness and modulus increased by 24% (P<0.001) and 20% (P<0.01), respectively. Although none of the tendon adaptations were related to strength gains, we observed a positive correlation between the increase in quadriceps PCSA and the increases in tendon stiffness (r=0.68; P<0.01) and modulus (r=0.75; P<0.01). Unexpectedly, the increase in muscle PCSA was inversely related to the distal and the mean increases in tendon CSA (in both cases, r=-0.64; P<0.05). These data suggest that, following short-term resistance training, changes in tendon mechanical and material properties are more closely related to the overall loading history and that tendon hypertrophy is driven by other mechanisms than those eliciting tendon stiffening.

  15. Where do injectable stem cell treatments apply in treatment of muscle, tendon, and ligament injuries?

    PubMed

    Mautner, Kenneth; Blazuk, Joseph

    2015-04-01

    Treatment options for muscle, tendon, and ligament injuries span a constantly evolving spectrum. For years, treatments focused on symptomatic relief. Closer scrutiny of symptomatic treatment suggests that the provision of transient relief of symptoms may have caused more harm than good. Cortisone injections provide a trade-off of short-term relief for poorer long-term outcomes. When conventional treatment failed, patients have faced limited options including surgery, which has increased risk and limited efficacy. Regenerative injections offer a more robust option for soft tissue disease. Basic science and clinical studies show conflicting results to support the use of platelet-rich plasma injections for soft tissue disorders, and even fewer trials have focused on injectable stem cells with limited findings. Additional studies are needed to determine the potential benefits of this regenerative therapy. PMID:25864658

  16. Muscle and tendon connective tissue adaptation to unloading, exercise and NSAID.

    PubMed

    Dideriksen, Kasper

    2014-04-01

    The extracellular matrix network of skeletal muscle and tendon connective tissue is primarily composed of collagen and connects the muscle contractile protein to the bones in the human body. The mechanical properties of the connective tissue are important for the effectiveness of which the muscle force is transformed into movement. Periods of unloading and exercise affect the synthesis rate of connective tissue collagen protein, whereas only sparse information exits regarding collagen protein degradation. It is likely, though, that changes in both collagen protein synthesis and degradation are required for remodeling of the connective tissue internal structure that ultimately results in altered mechanical properties of the connective tissue. Both unloading and exercise lead to increased production of growth factors and inflammatory mediators that are involved in connective tissue remodeling. Despite the fact that non-steroidal anti-inflammatory drugs seem to inhibit the healing process of connective tissue and the stimulating effect of exercise on connective tissue protein synthesis, these drugs are often consumed in relation to connective tissue injury and soreness. However, the potential effect of non-steroidal anti-inflammatory drugs on connective tissue needs further investigation.

  17. Relationship between tendon stiffness and failure: a metaanalysis

    PubMed Central

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

    2013-01-01

    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 (R2 = 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

  18. 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.

  19. Influence of parallel spring-loaded exoskeleton on ankle muscle-tendon dynamics during simulated human hopping.

    PubMed

    Robertson, Benjamin D; Sawicki, Gregory S

    2011-01-01

    Robotic assistance for rehabilitation and enhancement of human locomotion has become a major goal of biomedical engineers in recent years. While significant progress to this end has been made in the fields of neural interfacing and control systems, little has been done to examine the effects of mechanical assistance on the biomechanics of underlying muscle-tendon systems. Here, we model the effects of mechanical assistance via a passive spring acting in parallel with the triceps surae-Achilles tendon complex during cyclic hopping in humans. We examine system dynamics over a range of biological muscle activation and exoskeleton spring stiffness. We find that, in most cases, uniform cyclic mechanical power production of the coupled system is achieved. Furthermore, unassisted power production can be reproduced throughout parameter space by trading off decreases in muscle activation with increases in ankle exoskeleton spring stiffness. In addition, we show that as mechanical assistance increases the biological muscle-tendon unit becomes less 'tuned' resulting in higher mechanical power output from active components of muscle despite large reductions in required force output.

  20. A practical biomechanical model of the index finger simulating the kinematics of the muscle/tendon excursions.

    PubMed

    Wu, John Z; An, Kai-Nan; Cutlip, Robert G; Dong, Ren G

    2010-01-01

    Biomechanical models of the hand and fingers are useful tools for hand surgeons to improve surgical procedures and for biomedical researchers to explore the mechanical loading in the musculoskeletal system that cannot be easily measured in vivo. The purpose of the present study was to develop a realistic index finger model for solving practical problems. The model includes the meshes of four bony sections (distal, middle, proximal and metacarpal bones) obtained via micro-CT scans. The tendon attachment sites are adopted from the normative finger model. A total of seven tendon/muscles are included in the model. The predicted tendon excursions and moment arms were compared with published experimental data. One of the advantages of the current approach over previous studies is that the current model has been developed on a platform of a commercial software package, such that researchers can apply it as a universal tool for practical problems.

  1. Biomechanics of Tendon Transfers.

    PubMed

    Livermore, Andrew; Tueting, Jonathan L

    2016-08-01

    The transfer of tendons in the upper extremity is a powerful technique to restore function to a partially paralyzed hand. The biomechanical principles of muscle tension and tendon excursion dictate motor function both in the native as well as transferred states. Appropriately tensioning transferred tendons to maximize the function of the associated muscle remains an area of focused research. Newer methods of tendon coaptation have proven similar in strength to the standard Pulvertaft weave, affording more options to the surgeon. PMID:27387073

  2. Muscle-tendon unit stiffness does not independently affect voluntary explosive force production or muscle intrinsic contractile properties.

    PubMed

    Hannah, Ricci; Folland, Jonathan P

    2015-01-01

    This study examined the relationship of muscle-tendon unit (MTU) stiffness and explosive force production during voluntary and evoked contractions of the knee extensors. Thirty-four untrained participants performed a series of explosive voluntary and electrically evoked (octets (8 pulses, 300 Hz) via femoral nerve stimulation) isometric contractions. Maximum voluntary force (MVF) was assessed during maximum voluntary contractions. Explosive force production was assessed as the time taken, from force onset (0 N), to achieve specific levels of absolute (25-300 N) and relative force (5%-75% MVF) during the explosive contractions. Ultrasonic images of the vastus lateralis were recorded during 10-s ramp contractions to assess MTU stiffness, which was expressed in absolute (N · mm(-1)) and relative (to MVF and resting tendon-aponeurosis length) terms. Bivariate correlations suggested that absolute MTU stiffness was associated with voluntary explosive force (time to achieve 150-300 N: r = -0.35 to -0.54, P < 0.05). However, no relationships between stiffness and voluntary explosive force were observed when the influence of MVF was removed, either via partial correlations of absolute values (P ≥ 0.49) or considering relative values (P ≥ 0.14). Similarly, absolute MTU stiffness was related to explosive force during evoked octet contractions (r = -0.41 to -0.64, P < 0.05), but these correlations were no longer present when accounting for the influence of MVF (P ≥ 0.15). Therefore, once maximum strength was considered, MTU stiffness had no independent relationship with voluntary explosive force production or the evoked capacity for explosive force.

  3. Modeling of multiarticular muscles: importance of inclusion of tendon-pulley interactions in the finger.

    PubMed

    Lee, Sang Wook; Kamper, Derek G

    2009-09-01

    The purpose of this study was to examine force transmission from one of the major multiarticular muscles of the finger, flexor digitorum profundus (FDP), to the index finger. Specifically, we examined whether the popular moment arm (MA)-joint torque technique of modeling muscle force transmission can accurately represent the effects of the FDP on finger movement. A dynamic finger model employing geometric MA values (model I) was compared with another model including realistic tendon force transformation mechanisms via pulley structures and joint reaction forces (model II). Finger flexion movements generated by these models were compared with those obtained from in vivo stimulation experiments. The model with the force transformation mechanisms (model II) resulted in more realistic joint spatial coordination (i.e., proximal interphalangeal > metacarpophalangeal > or = distal interphalangeal) than the MA-based model (model I) in relation to the movement patterns evoked by stimulation. Also, the importance of the pulley structures and passive joint characteristics was confirmed in the model simulation; altering/eliminating these components significantly changed the spatial coordination of the joint angles during the resulting movements. The results of this study emphasize the functional importance of the force transformation through various biomechanical components, and suggest the importance of including these components when investigating finger motor control, such as for examining injury mechanisms or designing rehabilitation protocols.

  4. Exploratory factor analysis for differentiating sensory and mechanical variables related to muscle-tendon unit elongation

    PubMed Central

    Chagas, Mauro H.; Magalhães, Fabrício A.; Peixoto, Gustavo H. C.; Pereira, Beatriz M.; Andrade, André G. P.; Menzel, Hans-Joachim K.

    2016-01-01

    ABSTRACT Background Stretching exercises are able to promote adaptations in the muscle-tendon unit (MTU), which can be tested through physiological and biomechanical variables. Identifying the key variables in MTU adaptations is crucial to improvements in training. Objective To perform an exploratory factor analysis (EFA) involving the variables often used to evaluate the response of the MTU to stretching exercises. Method Maximum joint range of motion (ROMMAX), ROM at first sensation of stretching (FSTROM), peak torque (torqueMAX), passive stiffness, normalized stiffness, passive energy, and normalized energy were investigated in 36 participants during passive knee extension on an isokinetic dynamometer. Stiffness and energy values were normalized by the muscle cross-sectional area and their passive mode assured by monitoring the EMG activity. Results EFA revealed two major factors that explained 89.68% of the total variance: 53.13% was explained by the variables torqueMAX, passive stiffness, normalized stiffness, passive energy, and normalized energy, whereas the remaining 36.55% was explained by the variables ROMMAX and FSTROM. Conclusion This result supports the literature wherein two main hypotheses (mechanical and sensory theories) have been suggested to describe the adaptations of the MTU to stretching exercises. Contrary to some studies, in the present investigation torqueMAX was significantly correlated with the variables of the mechanical theory rather than those of the sensory theory. Therefore, a new approach was proposed to explain the behavior of the torqueMAX during stretching exercises. PMID:27437715

  5. Biologics for tendon repair☆

    PubMed Central

    Docheva, Denitsa; Müller, Sebastian A.; Majewski, Martin; Evans, Christopher H.

    2015-01-01

    Tendon injuries are common and present a clinical challenge to orthopedic surgery mainly because these injuries often respond poorly to treatment and require prolonged rehabilitation. Therapeutic options used to repair ruptured tendons have consisted of suture, autografts, allografts, and synthetic prostheses. To date, none of these alternatives has provided a successful long-term solution, and often the restored tendons do not recover their complete strength and functionality. Unfortunately, our understanding of tendon biology lags far behind that of other musculoskeletal tissues, thus impeding the development of new treatment options for tendon conditions. Hence, in this review, after introducing the clinical significance of tendon diseases and the present understanding of tendon biology, we describe and critically assess the current strategies for enhancing tendon repair by biological means. These consist mainly of applying growth factors, stem cells, natural biomaterials and genes, alone or in combination, to the site of tendon damage. A deeper understanding of how tendon tissue and cells operate, combined with practical applications of modern molecular and cellular tools could provide the long awaited breakthrough in designing effective tendon-specific therapeutics and overall improvement of tendon disease management. PMID:25446135

  6. Knee extension and flexion muscle power after anterior cruciate ligament reconstruction with patellar tendon graft or hamstring tendons graft: a cross-sectional comparison 3 years post surgery.

    PubMed

    Ageberg, Eva; Roos, Harald P; Silbernagel, Karin Grävare; Thomeé, Roland; Roos, Ewa M

    2009-02-01

    Hamstring muscles play a major role in knee-joint stabilization after anterior cruciate ligament (ACL) injury. Weakness of the knee extensors after ACL reconstruction with patellar tendon (PT) graft, and in the knee flexors after reconstruction with hamstring tendons (HT) graft has been observed up to 2 years post surgery, but not later. In these studies, isokinetic muscle torque was used. However, muscle power has been suggested to be a more sensitive and sport-specific measures of strength. The aim was to study quadriceps and hamstring muscle power in patients with ACL injury treated with surgical reconstruction with PT or HT grafts at a mean of 3 years after surgery. Twenty subjects with PT and 16 subjects with HT grafts (mean age at follow up 30 years, range 20-39, 25% women), who were all included in a prospective study and followed the same goal-based rehabilitation protocol for at least 4 months, were assessed with reliable, valid, and responsive tests of quadriceps and hamstring muscle power at 3 years (SD 0.9, range 2-5) after surgery. The mean difference between legs (injured minus uninjured), the hamstring to quadriceps (H:Q, hamstring divided by quadriceps) ratio, and the limb symmetry index (LSI, injured leg divided by uninjured and multiplied by 100) value, were used for comparisons between the groups (analysis of variance). The mean difference between the injured and uninjured legs was greater in the HT than in the PT group for knee flexion power (-21.3 vs. 7.7 W, p = 0.001). Patients with HT graft had lower H:Q ratio in the injured leg than the patients with PT graft (0.63 vs. 0.77, p = 0.012). They also had lower LSI for knee flexion power than those in the PT group (88 vs. 106%, p < 0.001). No differences were found between the groups for knee extension power. The lower hamstring muscle power, and the lower hamstring to quadriceps ratio in the HT graft group than in the PT graft group 3 years (range 2-5) after ACL reconstruction, reflect imbalance

  7. Age-related greater Achilles tendon compliance is not associated with larger plantar flexor muscle fascicle strains in senior women.

    PubMed

    Csapo, R; Malis, V; Hodgson, J; Sinha, S

    2014-04-15

    The aim of the present study was to test the hypothesis that the age-associated decrease of tendon stiffness would necessitate greater muscle fascicle strains to produce similar levels of force during isometric contraction. Greater fascicle strains could force sarcomeres to operate in less advantageous regions of their force-length and force-velocity relationships, thus impairing the capacity to generate strong and explosive contractions. To test this hypothesis, sagittal-plane dynamic velocity-encoded phase-contrast magnetic resonance images of the gastrocnemius medialis (GM) muscle and Achilles tendon (AT) were acquired in six young (YW; 26.1 ± 2.3 yr) and six senior (SW; 76.7 ± 8.3 yr) women during submaximal isometric contraction (35% maximum voluntary isometric contraction) of the plantar flexor muscles. Multiple GM fascicle lengths were continuously determined by automatically tracking regions of interest coinciding with the end points of muscle fascicles evenly distributed along the muscle's proximo-distal length. AT stiffness and Young's modulus were measured as the slopes of the tendon's force-elongation and stress-strain curves, respectively. Despite significantly lower AT stiffness at older age (YW: 120.2 ± 52.3 N/mm vs. SW: 53.9 ± 44.4 N/mm, P = 0.040), contraction-induced changes in GM fascicle lengths were similar in both age groups at equal levels of absolute muscular force (4-5% fascicle shortening in both groups), and even significantly larger in YW (YW: 11-12% vs. SW: 6-8% fascicle shortening) at equal percentage of maximum voluntary contraction. These results suggest that factors other than AT stiffness, such as age-associated changes in muscle composition or fascicle slack, might serve as compensatory adaptations, limiting the degree of fascicle strains upon contraction.

  8. The influence of increased muscle spindle sensitivity on Achilles tendon jerk and H-reflex in relaxed human subjects.

    PubMed

    Rossi-Durand, Christiane

    2002-01-01

    Whether the fusimotor system contributes to reflex gain changes during reinforcement maneuvers is re-examined in the light of new data. Recently, from direct recordings of spindle afferent activity originating from ankle flexor muscles, we showed that mental computation increased the muscle spindle mechanical sensitivity in completely relaxed human subjects without concomitant alpha-motoneuron activation, providing evidence for selective fusimotor drive activation. In the present study, the effects of mental computation were investigated on monosynaptic reflexes elicited in non-contracting soleus muscle either by direct nerve stimulation (Hoffmann reflex, H) or by tendon tap (Tendinous reflex, T). The aim was to relate the time course of the changes in reflex size to the increase in spindle sensitivity during mental task in order to explore whether fusimotor activation can influence the size of the monosynaptic reflex. The results show changes in reflex amplitude that parallel the increase in muscle spindle sensitivity. When T-reflex is consistently facilitated during mental effort, the H-reflex is either depressed or facilitated, depending on the subjects. These findings suggest that the increased activity in muscle spindle primary endings may account for mental computation-induced changes in both tendon jerk and H-reflex. The facilitation of T-reflex is attributed to the enhanced spindle mechanical sensitivity and the inhibition of H-reflex is attributed to post-activation depression following the increased Ia ongoing discharge. This study supports the view that the fusimotor sensitization of muscle spindles is responsible for changes in both the mechanically and electrically elicited reflexes. It is concluded that the fusimotor drive contributed to adjustment of the size of tendon jerk and H-reflex during mental effort. The possibility that a mental computation task may also operate by reducing the level of presynaptic inhibition is discussed on the basis of H

  9. Extended healing validation of an artificial tendon to connect the quadriceps muscle to the Tibia: 180-day study.

    PubMed

    Melvin, Alan J; Litsky, Alan S; Mayerson, Joel L; Stringer, Keith; Juncosa-Melvin, Natalia

    2012-07-01

    Whenever a tendon or its bone insertion is disrupted or removed, existing surgical techniques provide a temporary connection or scaffolding to promote healing, but the interface of living to non-living materials soon breaks down under the stress of these applications, if it must bear the load more than acutely. Patients are thus disabled whose prostheses, defect size, or mere anatomy limit the availability or outcomes of such treatments. Our group developed the OrthoCoupler™ device to join skeletal muscle to prosthetic or natural structures without this interface breakdown. In this study, the goat knee extensor mechanism (quadriceps tendon, patella, and patellar tendon) was removed from the right hind limb in 16 goats. The device connected the quadriceps muscle to a stainless steel bone plate on the tibia. Mechanical testing and histology specimens were collected from each operated leg and contralateral unoperated control legs at 180 days. Maximum forces in the operated leg (vs. unoperated) were 1,400 ± 93 N (vs. 1,179 ± 61 N), linear stiffnesses were 33 ± 3 N/mm (vs. 37 ± 4 N/mm), and elongations at failure were 92.1 ± 5.3 mm (vs. 68.4 ± 3.8 mm; mean ± SEM). Higher maximum forces (p = 0.02) and elongations at failure (p=0.008) of legs with the device versus unoperated controls were significant; linear stiffnesses were not (p=0.3). We believe this technology will yield improved procedures for clinical challenges in orthopedic oncology, revision arthroplasty, tendon transfer, and tendon injury reconstruction.

  10. Extended Healing Validation of an Artificial Tendon to Connect the Quadriceps Muscle to the Tibia: 180-day Study

    PubMed Central

    Melvin, Alan J.; Litsky, Alan S.; Mayerson, Joel L.; Stringer, Keith; Juncosa-Melvin, Natalia

    2011-01-01

    Whenever a tendon or its bone insertion is disrupted or removed, existing surgical techniques provide a temporary connection or scaffolding to promote healing, but the interface of living to nonliving materials soon breaks down under the stress of these applications, if it must bear the load more than acutely. Patients are thus disabled whose prostheses, defect size, or mere anatomy limit the availability or outcomes of such treatments. Our group developed the OrthoCoupler™ device to join skeletal muscle to prosthetic or natural structures without this interface breakdown. In this study, the goat knee extensor mechanism (quadriceps tendon, patella, and patellar tendon) was removed from the right hind limb in 16 goats. The device connected the quadriceps muscle to a stainless steel bone plate on the tibia. Mechanical testing and histology specimens were collected from each operated leg and contra lateral unoperated control legs at 180 days. Maximum forces in the operated leg (vs. unoperated) were 1400± 93N (vs. 1179± 61 N), linear stiffnesses were 33± 3 N/mm (vs. 37 ± 4N/mm), and elongations at failure were 92.1 ± 5.3 mm (vs. 68.4 ± 3.8 mm; mean ± SEM). Higher maximum forces (p = 0.02) and elongations at failure (p = 0.008) of legs with the device versus unoperated controls were significant; linear stiffnesses were not (p = 0.3). We believe this technology will yield improved procedures for clinical challenges in orthopaedic oncology, revision arthroplasty, tendon transfer, and tendon injury reconstruction. PMID:22179930

  11. Normal aging alters in vivo passive biomechanical response of the rat gastrocnemius-Achilles muscle-tendon unit.

    PubMed

    Plate, Johannes F; Wiggins, Walter F; Haubruck, Patrick; Scott, Aaron T; Smith, Thomas L; Saul, Katherine R; Mannava, Sandeep

    2013-02-01

    Predisposition to Achilles tendon (AT) ruptures in middle-aged individuals may be associated with age-related changes to inherent passive biomechanical properties of the gastrocnemius-Achilles (GC-AT) muscle-tendon unit, due to known muscle-tendon structural changes in normal aging. The goal of this study was to determine whether the passive biomechanical response of the GC-AT muscle-tendon unit was altered with age in 6 young (8 months) and 6 middle-aged (24 months) F344xBN hybrid rats from the National Institute on Aging colony. Fung's quasilinear viscoelastic (QLV) model was used to determine in vivo history and time-dependent load-relaxation response of the GC-AT. Effective stiffness and modulus were also estimated using linear regression analysis. Fung's QLV revealed a significantly decreased magnitude of the relaxation response (parameter C, p=0.026) in middle-aged animals compared to young animals (0.108±0.007 vs. 0.144±0.015), with similar time-dependent viscous GC-AT properties (τ(1), τ(2)). The product of elastic parameters (A*B), which represents the initial slope of the elastic response, was significantly increased by 50% in middle-aged rats (p=0.014). Estimated GC-AT stiffness increased 28% at peak tensions in middle-aged rats (2.7±0.2 N/mm) compared to young rats (1.9±0.2 N/mm; p=0.036). While the limitations of this animal model must be considered, the changes we describe could be associated with the observation that GC-AT pathology and injury is more common in middle-aged individuals. Further studies are necessary to characterize the load-to-failure behavior of AT in middle-aged compared to young animals.

  12. Tendon Gradient Mineralization for Tendon to Bone Interface Integration

    PubMed Central

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

    2014-01-01

    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 5 groups: 1) normal FDP tendon, 2) CaP (Non-extraction and mineralization without fetuin), 3) CaPEXT (Extraction by Na2HPO4 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

  13. 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.

  14. Isokinetic quadriceps and hamstring muscle strength and knee function 5 years after anterior cruciate ligament reconstruction: comparison between bone-patellar tendon-bone and hamstring tendon autografts.

    PubMed

    Lautamies, Riitta; Harilainen, Arsi; Kettunen, Jyrki; Sandelin, Jerker; Kujala, Urho M

    2008-11-01

    Existing clinical studies have not proven which graft is to be preferred in anterior cruciate ligament (ACL) reconstruction. In recent years, bone-patellar tendon-bone and hamstring tendons have been the most frequently used graft types. Muscle strength deficit is one of the consequences after ACL reconstruction. The aim of this study was to evaluate possible differences in hamstring and quadriceps muscle strength and knee function 5 years after ACL reconstruction between the BPTB and the STG groups. The study group consisted of 288 patients (132 women, 156 men) with a unilateral ACL rupture who had received a BPTB (175 patients) or STG (113 patients) ACL reconstruction. Lower extremity concentric isokinetic peak extension and flexion torques were assessed at the angular velocities of 60 degrees /s and 180 degrees /s. The International Knee Documentation Committee (IKDC), the Tegner activity level, the Lysholm knee and the Kujala patellofemoral scores were also collected. Isokinetic quadriceps peak torque (percentage of the contralateral side) was 3.9% higher in the STG group than in the BPTB group at the velocity of 60 degrees /s and 3.2% higher at the velocity of 180 degrees /s and the isokinetic hamstring peak torque 2% higher in the BPTB group than in the STG group at the velocity of 60 degrees /s and 2.5% higher at the velocity of 180 degrees /s. In both groups the subjects had weaker quadriceps and hamstring muscle strength in the injured extremity compared with the uninjured one. In the single-leg hop test (according to the IKDC recommendations) there was a statistically significant difference (P = 0.040) between the groups. In the STG group, 68% of the patients had the single-leg hop ratio (injured vs. uninjured extremity) > or =90%, 31% of the patients 75-89% and 1% of the patients <75%, while in the BPTB group the corresponding percentages were 72, 21 and 7%. However, no statistically significant differences in clinical outcome were found between the

  15. Evolution of Skin Temperature after the Application of Compressive Forces on Tendon, Muscle and Myofascial Trigger Point.

    PubMed

    Magalhães, Marina Figueiredo; Dibai-Filho, Almir Vieira; de Oliveira Guirro, Elaine Caldeira; Girasol, Carlos Eduardo; de Oliveira, Alessandra Kelly; Dias, Fabiana Rodrigues Cancio; Guirro, Rinaldo Roberto de Jesus

    2015-01-01

    Some assessment and diagnosis methods require palpation or the application of certain forces on the skin, which affects the structures beneath, we highlight the importance of defining possible influences on skin temperature as a result of this physical contact. Thus, the aim of the present study is to determine the ideal time for performing thermographic examination after palpation based on the assessment of skin temperature evolution. Randomized and crossover study carried out with 15 computer-user volunteers of both genders, between 18 and 45 years of age, who were submitted to compressive forces of 0, 1, 2 and 3 kg/cm2 for 30 seconds with a washout period of 48 hours using a portable digital dynamometer. Compressive forces were applied on the following spots on the dominant upper limb: myofascial trigger point in the levator scapulae, biceps brachii muscle and palmaris longus tendon. Volunteers were examined by means of infrared thermography before and after the application of compressive forces (15, 30, 45 and 60 minutes). In most comparisons made over time, a significant decrease was observed 30, 45 and 60 minutes after the application of compressive forces (p < 0.05) on the palmaris longus tendon and biceps brachii muscle. However, no difference was observed when comparing the different compressive forces (p > 0.05). In conclusion, infrared thermography can be used after assessment or diagnosis methods focused on the application of forces on tendons and muscles, provided the procedure is performed 15 minutes after contact with the skin. Regarding to the myofascial trigger point, the thermographic examination can be performed within 60 minutes after the contact with the skin.

  16. Evolution of Skin Temperature after the Application of Compressive Forces on Tendon, Muscle and Myofascial Trigger Point

    PubMed Central

    Magalhães, Marina Figueiredo; Dibai-Filho, Almir Vieira; de Oliveira Guirro, Elaine Caldeira; Girasol, Carlos Eduardo; de Oliveira, Alessandra Kelly; Dias, Fabiana Rodrigues Cancio; Guirro, Rinaldo Roberto de Jesus

    2015-01-01

    Some assessment and diagnosis methods require palpation or the application of certain forces on the skin, which affects the structures beneath, we highlight the importance of defining possible influences on skin temperature as a result of this physical contact. Thus, the aim of the present study is to determine the ideal time for performing thermographic examination after palpation based on the assessment of skin temperature evolution. Randomized and crossover study carried out with 15 computer-user volunteers of both genders, between 18 and 45 years of age, who were submitted to compressive forces of 0, 1, 2 and 3 kg/cm2 for 30 seconds with a washout period of 48 hours using a portable digital dynamometer. Compressive forces were applied on the following spots on the dominant upper limb: myofascial trigger point in the levator scapulae, biceps brachii muscle and palmaris longus tendon. Volunteers were examined by means of infrared thermography before and after the application of compressive forces (15, 30, 45 and 60 minutes). In most comparisons made over time, a significant decrease was observed 30, 45 and 60 minutes after the application of compressive forces (p < 0.05) on the palmaris longus tendon and biceps brachii muscle. However, no difference was observed when comparing the different compressive forces (p > 0.05). In conclusion, infrared thermography can be used after assessment or diagnosis methods focused on the application of forces on tendons and muscles, provided the procedure is performed 15 minutes after contact with the skin. Regarding to the myofascial trigger point, the thermographic examination can be performed within 60 minutes after the contact with the skin. PMID:26070073

  17. More is not always better: modeling the effects of elastic exoskeleton compliance on underlying ankle muscle-tendon dynamics.

    PubMed

    Robertson, Benjamin D; Farris, Dominic J; Sawicki, Gregory S

    2014-01-01

    Development of robotic exoskeletons to assist/enhance human locomotor performance involves lengthy prototyping, testing, and analysis. This process is further convoluted by variability in limb/body morphology and preferred gait patterns between individuals. In an attempt to expedite this process, and establish a physiological basis for actuator prescription, we developed a simple, predictive model of human neuromechanical adaptation to a passive elastic exoskeleton applied at the ankle joint during a functional task. We modeled the human triceps surae-Achilles tendon muscle tendon unit (MTU) as a single Hill-type muscle, or contractile element (CE), and series tendon, or series elastic element (SEE). This modeled system was placed under gravitational load and underwent cyclic stimulation at a regular frequency (i.e. hopping) with and without exoskeleton (Exo) assistance. We explored the effect that both Exo stiffness (kExo) and muscle activation (Astim) had on combined MTU and Exo (MTU + Exo), MTU, and CE/SEE mechanics and energetics. Model accuracy was verified via qualitative and quantitative comparisons between modeled and prior experimental outcomes. We demonstrated that reduced Astim can be traded for increased kExo to maintain consistent MTU + Exo mechanics (i.e. average positive power (P⁺mech) output) from an unassisted condition (i.e. kExo = 0 kN · m⁻¹). For these regions of parameter space, our model predicted a reduction in MTU force, SEE energy cycling, and metabolic rate (Pmet), as well as constant CE P⁺mech output compared to unassisted conditions. This agreed with previous experimental observations, demonstrating our model's predictive ability. Model predictions also provided insight into mechanisms of metabolic cost minimization, and/or enhanced mechanical performance, and we concluded that both of these outcomes cannot be achieved simultaneously, and that one must come at the detriment of the other in a spring-assisted compliant MTU.

  18. Orthopedic applications of acellular human dermal allograft for shoulder and elbow surgery.

    PubMed

    Acevedo, Daniel C; Shore, Brett; Mirzayan, Raffy

    2015-07-01

    Shoulder and elbow tendon injuries are some of the most challenging problems to treat surgically. Tendon repairs in the upper extremity can be complicated by poor tendon quality and, often times, poor healing. Extracellular matrices, such as human dermal allografts, have been used to augment tendon repairs in shoulder and elbow surgery. The indications and surgical techniques regarding the use of human dermal allograft continue to evolve. This article reviews the basic science, rationale for use, and surgical applications of human dermal allograft in shoulder and elbow tendon injuries.

  19. Tendon and skeletal muscle matrix gene expression and functional responses to immobilisation and rehabilitation in young males: effect of growth hormone administration

    PubMed Central

    Boesen, A P; Dideriksen, K; Couppé, C; Magnusson, S P; Schjerling, P; Boesen, M; Kjaer, M; Langberg, H

    2013-01-01

    We examined the effect of growth hormone (GH) on connective tissue of tendon and skeletal muscle during immobilisation and re-training in humans. Young men (20–30 years; n= 20) were randomly assigned to daily recombinant human GH (rhGH) (33–50 μg kg−1 day−1) or placebo (Plc), and had one leg immobilised for 2 weeks, followed by 6 weeks of strength training. The cross-sectional area (CSA), maximal muscle strength (maximal voluntary contraction, MVC) and biomechanical properties of the quadriceps muscle and patellar tendon were determined. Muscle and tendon biopsies were analysed for mRNA of collagen (COL1A1/3A1), insulin-like growth factors (IGF-1Ea/Ec), lysyl oxidase (LOX), matrix metalloproteases (MMP-2 and MMP-9), decorin and tenascin-C. Fibril morphology was analysed by transmission electron microscopy (TEM) to detect changes in the fibril diameter distribution. In muscle, CSA and MVC declined with immobilisation and recovered with rehabilitation similarly in both groups. Likewise, both groups showed increased IGF-1Ea/Ec and COL1A1/3A1 expression in muscle during re-training after immobilisation compared with baseline, and the increase was more pronounced when subjects received GH. The tendon CSA did not change during immobilisation, but increased in both groups during 6 weeks of rehabilitation (∼14%). A decline in tendon stiffness after immobilisation was observed only in the Plc group, and an increase during 6 weeks of rehabilitation was observed only in the GH group. IGF-1Ea and COL1A1/3A1 mRNA increased with immobilisation in the GH group only, and LOX mRNA was higher in the GH group than in the Plc group after immobilisation. Both groups showed an increase in MMP-2 with immobilisation, whereas no changes in MMP-9, decorin and tenascin-C were observed. The tendon fibril diameter distribution remained unchanged in both groups. In conclusion, GH stimulates collagen expression in both skeletal muscle and tendon, abolishes the normal inactivity

  20. Tendon and skeletal muscle matrix gene expression and functional responses to immobilisation and rehabilitation in young males: effect of growth hormone administration.

    PubMed

    Boesen, A P; Dideriksen, K; Couppé, C; Magnusson, S P; Schjerling, P; Boesen, M; Kjaer, M; Langberg, H

    2013-12-01

    We examined the effect of growth hormone (GH) on connective tissue of tendon and skeletal muscle during immobilisation and re-training in humans. Young men (20-30 years; n = 20) were randomly assigned to daily recombinant human GH (rhGH) (33-50 μg kg(-1) day(-1)) or placebo (Plc), and had one leg immobilised for 2 weeks, followed by 6 weeks of strength training. The cross-sectional area (CSA), maximal muscle strength (maximal voluntary contraction, MVC) and biomechanical properties of the quadriceps muscle and patellar tendon were determined. Muscle and tendon biopsies were analysed for mRNA of collagen (COL1A1/3A1), insulin-like growth factors (IGF-1Ea/Ec), lysyl oxidase (LOX), matrix metalloproteases (MMP-2 and MMP-9), decorin and tenascin-C. Fibril morphology was analysed by transmission electron microscopy (TEM) to detect changes in the fibril diameter distribution. In muscle, CSA and MVC declined with immobilisation and recovered with rehabilitation similarly in both groups. Likewise, both groups showed increased IGF-1Ea/Ec and COL1A1/3A1 expression in muscle during re-training after immobilisation compared with baseline, and the increase was more pronounced when subjects received GH. The tendon CSA did not change during immobilisation, but increased in both groups during 6 weeks of rehabilitation (∼14%). A decline in tendon stiffness after immobilisation was observed only in the Plc group, and an increase during 6 weeks of rehabilitation was observed only in the GH group. IGF-1Ea and COL1A1/3A1 mRNA increased with immobilisation in the GH group only, and LOX mRNA was higher in the GH group than in the Plc group after immobilisation. Both groups showed an increase in MMP-2 with immobilisation, whereas no changes in MMP-9, decorin and tenascin-C were observed. The tendon fibril diameter distribution remained unchanged in both groups. In conclusion, GH stimulates collagen expression in both skeletal muscle and tendon, abolishes the normal inactivity

  1. Tendon and skeletal muscle matrix gene expression and functional responses to immobilisation and rehabilitation in young males: effect of growth hormone administration.

    PubMed

    Boesen, A P; Dideriksen, K; Couppé, C; Magnusson, S P; Schjerling, P; Boesen, M; Kjaer, M; Langberg, H

    2013-12-01

    We examined the effect of growth hormone (GH) on connective tissue of tendon and skeletal muscle during immobilisation and re-training in humans. Young men (20-30 years; n = 20) were randomly assigned to daily recombinant human GH (rhGH) (33-50 μg kg(-1) day(-1)) or placebo (Plc), and had one leg immobilised for 2 weeks, followed by 6 weeks of strength training. The cross-sectional area (CSA), maximal muscle strength (maximal voluntary contraction, MVC) and biomechanical properties of the quadriceps muscle and patellar tendon were determined. Muscle and tendon biopsies were analysed for mRNA of collagen (COL1A1/3A1), insulin-like growth factors (IGF-1Ea/Ec), lysyl oxidase (LOX), matrix metalloproteases (MMP-2 and MMP-9), decorin and tenascin-C. Fibril morphology was analysed by transmission electron microscopy (TEM) to detect changes in the fibril diameter distribution. In muscle, CSA and MVC declined with immobilisation and recovered with rehabilitation similarly in both groups. Likewise, both groups showed increased IGF-1Ea/Ec and COL1A1/3A1 expression in muscle during re-training after immobilisation compared with baseline, and the increase was more pronounced when subjects received GH. The tendon CSA did not change during immobilisation, but increased in both groups during 6 weeks of rehabilitation (∼14%). A decline in tendon stiffness after immobilisation was observed only in the Plc group, and an increase during 6 weeks of rehabilitation was observed only in the GH group. IGF-1Ea and COL1A1/3A1 mRNA increased with immobilisation in the GH group only, and LOX mRNA was higher in the GH group than in the Plc group after immobilisation. Both groups showed an increase in MMP-2 with immobilisation, whereas no changes in MMP-9, decorin and tenascin-C were observed. The tendon fibril diameter distribution remained unchanged in both groups. In conclusion, GH stimulates collagen expression in both skeletal muscle and tendon, abolishes the normal inactivity

  2. Tendon Structure and Composition.

    PubMed

    Thorpe, Chavaunne T; Screen, Hazel R C

    2016-01-01

    Tendons are soft, fibrous tissues that connect muscle to bone. Their main function is to transfer muscle generated force to the bony skeleton, facilitating movement around a joint, and as such they are relatively passive, inelastic structures, able to resist high forces. Tendons are predominantly composed of collagen, which is arranged in a hierarchical manner parallel to the long axis of the tendon, resulting in high tensile strength. Tendon also contains a range of non-collagenous proteins, present in low amounts, which nevertheless have important functional roles. In this chapter, we describe general tendon composition and structure, and discuss how variations in composition and structure at different levels of the tendon hierarchy confer specific mechanical properties, which are related to tendon function. PMID:27535244

  3. Musculoskeletal diseases—tendon

    PubMed Central

    Sakabe, Tomoya; Sakai, Takao

    2011-01-01

    Introduction Tendons establish specific connections between muscles and the skeleton by transferring contraction forces from skeletal muscle to bone thereby allowing body movement. Tendon physiology and pathology are heavily dependent on mechanical stimuli. Tendon injuries clinically represent a serious and still unresolved problem since damaged tendon tissues heal very slowly and no surgical treatment can restore a damaged tendon to its normal structural integrity and mechanical strength. Understanding how mechanical stimuli regulate tendon tissue homeostasis and regeneration will improve the treatment of adult tendon injuries that still pose a great challenge in today's medicine. Source of data This review summarizes the current status of tendon treatment and discusses new directions from the point of view of cell-based therapy and regenerative medicine approach. We searched the available literature using PubMed for relevant original articles and reviews. Growing points Identification of tendon cell markers has enabled us to study precisely tendon healing and homeostasis. Clinically, tissue engineering for tendon injuries is an emerging technology comprising elements from the fields of cellular source, scaffold materials, growth factors/cytokines and gene delivering systems. Areas timely for developing research The clinical settings to establish appropriate microenvironment for injured tendons with the combination of these novel cellular- and molecular-based scaffolds will be critical for the treatment. PMID:21729872

  4. Influence of muscle-tendon unit structure on rate of force development during the squat, countermovement, and drop jumps.

    PubMed

    Earp, Jacob E; Kraemer, William J; Cormie, Prue; Volek, Jeffery S; Maresh, Carl M; Joseph, Michael; Newton, Robert U

    2011-02-01

    Previous research has highlighted the importance of muscle and tendon structure to stretch shortening cycle performance. However, the relationships between muscle and tendon structure to performance are highly dependent on the speed and intensity of the movement. The purpose of this study was to determine if muscle and tendon structure is associated with the rate of force development (RFD) throughout static squat jump (SJ), countermovement jump (CMJ), and drop jump (DJ; 30-cm height). Twenty-five strength- and power-trained men participated in the study. Using ultrasonography, vastus lateralis (VL) and gastrocnemius (GAS) pennation (PEN) and fascicle length (FL), and Achilles tendon (AT) thickness and length were measured. Subjects then performed SJ, CMJ, and DJ, during which RFD was calculated over time 5 distinct time intervals. During CMJs, early RFD could be predicted between 0 and 10 milliseconds by both GAS-FL (r² = 0.213, β = 0.461) and AT-length (r² = 0.191, β = 20.438). Between 10 and 30 milliseconds GAS-FL was a significant predictor of CMJ-RFD (r² = 0.218, β = 0.476). During DJ, initial RFD (0-10 milliseconds) could be significantly predicted by GAS-FL (r² = 0.185, β = 20.434), VL-PEN (r² = 0.189, β = 0.435), and GAS-PEN (r² = 0.188, β = 0.434). These findings suggest that longer ATs may have increased elasticity, which can decrease initial RFD during CMJ; thus, their use in talent identification is not recommended. The GAS fascicle length had an intensity-dependent relationship with RFD, serving to positively predict RFD during early CMJs and an inverse predictor during early DJs. During DDJs, subjects with greater PEN were better able to redirected initial impact forces. Although both strength and plyometric training have been shown to increase FL, only heavy strength training has been shown to increase PEN. Thus, when a high eccentric load or multiple jumps are required, heavy strength training might be used to elicit muscular adaptations

  5. Exploiting elasticity: Modeling the influence of neural control on mechanics and energetics of ankle muscle-tendons during human hopping.

    PubMed

    Robertson, Benjamin D; Sawicki, Gregory S

    2014-07-21

    We present a simplified Hill-type model of the human triceps surae-Achilles tendon complex working on a gravitational-inertial load during cyclic contractions (i.e. vertical hopping). Our goal was to determine the role that neural control plays in governing muscle, or contractile element (CE), and tendon, or series elastic element (SEE), mechanics and energetics within a compliant muscle-tendon unit (MTU). We constructed a 2D parameter space consisting of many combinations of stimulation frequency and magnitude (i.e. neural control strategies). We compared the performance of each control strategy by evaluating peak force and average positive mechanical power output for the system (MTU) and its respective components (CE, SEE), force-length (F-L) and -velocity (F-V) operating point of the CE during active force production, average metabolic rate for the CE, and both MTU and CE apparent efficiency. Our results suggest that frequency of stimulation plays a primary role in governing whole-MTU mechanics. These include the phasing of both activation and peak force relative to minimum MTU length, average positive power, and apparent efficiency. Stimulation amplitude was primarily responsible for governing average metabolic rate and within MTU mechanics, including peak force generation and elastic energy storage and return in the SEE. Frequency and amplitude of stimulation both played integral roles in determining CE F-L operating point, with both higher frequency and amplitude generally corresponding to lower CE strains, reduced injury risk, and elimination of the need for passive force generation in the CE parallel elastic element (PEE).

  6. The role of human ankle plantar flexor muscle-tendon interaction and architecture in maximal vertical jumping examined in vivo.

    PubMed

    Farris, Dominic James; Lichtwark, Glen A; Brown, Nicholas A T; Cresswell, Andrew G

    2016-02-01

    Humans utilise elastic tendons of lower limb muscles to store and return energy during walking, running and jumping. Anuran and insect species use skeletal structures and/or dynamics in conjunction with similarly compliant structures to amplify muscle power output during jumping. We sought to examine whether human jumpers use similar mechanisms to aid elastic energy usage in the plantar flexor muscles during maximal vertical jumping. Ten male athletes performed maximal vertical squat jumps. Three-dimensional motion capture and a musculoskeletal model were used to determine lower limb kinematics that were combined with ground reaction force data in an inverse dynamics analysis. B-mode ultrasound imaging of the lateral gastrocnemius (GAS) and soleus (SOL) muscles was used to measure muscle fascicle lengths and pennation angles during jumping. Our results highlighted that both GAS and SOL utilised stretch and recoil of their series elastic elements (SEEs) in a catapult-like fashion, which likely serves to maximise ankle joint power. The resistance of supporting of body weight allowed initial stretch of both GAS and SOL SEEs. A proximal-to-distal sequence of joint moments and decreasing effective mechanical advantage early in the extension phase of the jumping movement were observed. This facilitated a further stretch of the SEE of the biarticular GAS and delayed recoil of the SOL SEE. However, effective mechanical advantage did not increase late in the jump to aid recoil of elastic tissues.

  7. Sensitivity of subject-specific models to Hill muscle-tendon model parameters in simulations of gait.

    PubMed

    Carbone, V; van der Krogt, M M; Koopman, H F J M; Verdonschot, N

    2016-06-14

    Subject-specific musculoskeletal (MS) models of the lower extremity are essential for applications such as predicting the effects of orthopedic surgery. We performed an extensive sensitivity analysis to assess the effects of potential errors in Hill muscle-tendon (MT) model parameters for each of the 56 MT parts contained in a state-of-the-art MS model. We used two metrics, namely a Local Sensitivity Index (LSI) and an Overall Sensitivity Index (OSI), to distinguish the effect of the perturbation on the predicted force produced by the perturbed MT parts and by all the remaining MT parts, respectively, during a simulated gait cycle. Results indicated that sensitivity of the model depended on the specific role of each MT part during gait, and not merely on its size and length. Tendon slack length was the most sensitive parameter, followed by maximal isometric muscle force and optimal muscle fiber length, while nominal pennation angle showed very low sensitivity. The highest sensitivity values were found for the MT parts that act as prime movers of gait (Soleus: average OSI=5.27%, Rectus Femoris: average OSI=4.47%, Gastrocnemius: average OSI=3.77%, Vastus Lateralis: average OSI=1.36%, Biceps Femoris Caput Longum: average OSI=1.06%) and hip stabilizers (Gluteus Medius: average OSI=3.10%, Obturator Internus: average OSI=1.96%, Gluteus Minimus: average OSI=1.40%, Piriformis: average OSI=0.98%), followed by the Peroneal muscles (average OSI=2.20%) and Tibialis Anterior (average OSI=1.78%) some of which were not included in previous sensitivity studies. Finally, the proposed priority list provides quantitative information to indicate which MT parts and which MT parameters should be estimated most accurately to create detailed and reliable subject-specific MS models. PMID:27131851

  8. Effect of growth hormone on aging connective tissue in muscle and tendon: gene expression, morphology, and function following immobilization and rehabilitation.

    PubMed

    Boesen, A P; Dideriksen, K; Couppé, C; Magnusson, S P; Schjerling, P; Boesen, M; Aagaard, P; Kjaer, M; Langberg, H

    2014-01-15

    It is unknown whether loss in musculotendinous tissue during inactivity can be counteracted by growth hormone (GH), and whether GH accelerate rehabilitation in aging individuals. Elderly men (65-75 yr; n = 12) had one leg immobilized 2 wk followed by 6 wk of retraining and were randomly assigned to daily injections of recombinant GH (rhGH; n = 6) or placebo (Plc; n = 6). Cross-sectional area (CSA), muscle strength (MVC), and biomechanical properties of m. quadriceps and patellar tendon were determined. Muscle and tendon biopsies were analyzed for gene expressions (mRNA) of collagen (COL1A1/3A1) and insulin-like growth factors (IGF-1Ea/Ec). Fibril morphology was analyzed by transmission electron microscope (TEM). In tendon, CSA and biomechanical properties did not change following immobilization, but an increase in CSA was found after 6 wk of rehabilitation in both groups. The changes were more pronounced when GH was injected. Furthermore, tendon stiffness increased in the GH group. Muscle CSA declined after immobilization in the Plc but not in the GH group. Muscle CSA increased during retraining, with a significantly larger increase in the GH group compared with the Plc group. Both a time and a group effect were seen for IGF-1Ea/Ec and COL1A1/3A1 mRNA expression in muscle, with a difference between GH and Plc. IGF-1Ea/Ec and COL-1A1/3A1 mRNA expression increased in muscle following immobilization and retraining in subjects receiving GH, whereas an increase in IGF-1Ec mRNA expression was seen in the Plc group only after retraining. In conclusion, in elderly humans, GH seems to have a matrix stabilizing effect during inactivity and rehabilitation by stimulating collagen expression in the musculotendinous tissue and increasing tendon CSA and stiffness. PMID:24235105

  9. Tendon development and diseases.

    PubMed

    Gaut, Ludovic; Duprez, Delphine

    2016-01-01

    Tendon is a uniaxial connective tissue component of the musculoskeletal system. Tendon is involved in force transmission between muscle and bone. Tendon injury is very common and debilitating but tendon repair remains a clinical challenge for orthopedic medicine. In vertebrates, tendon is mainly composed of type I collagen fibrils, displaying a parallel organization along the tendon axis. The tendon-specific spatial organization of type I collagen provides the mechanical properties for tendon function. In contrast to other components of the musculoskeletal system, tendon biology is poorly understood. An important goal in tendon biology is to understand the mechanisms involved in the production and assembly of type I collagen fibrils during development, postnatal formation, and healing processes in order to design new therapies for tendon repair. In this review we highlight the current understanding of the molecular and mechanical signals known to be involved in tenogenesis during development, and how development provides insights into tendon healing processes. WIREs Dev Biol 2016, 5:5-23. doi: 10.1002/wdev.201 For further resources related to this article, please visit the WIREs website.

  10. Electromechanical delay of the knee extensor muscles is not altered after harvesting the patellar tendon as a graft for ACL reconstruction: implications for sports performance.

    PubMed

    Georgoulis, A D; Ristanis, S; Papadonikolakis, A; Tsepis, E; Moebius, U; Moraiti, C; Stergiou, N

    2005-09-01

    Although the scar tissue, which heals the donor site defect, has different elasticity from the neighbouring patellar tissue, it remains unclear if this scar tissue can lead to the changes of the electromechanical delay (EMD) of the knee extensor muscles. If such changes do exist, they can possibly affect both the utilization of the stored energy in the series elastic component, as well as the optimal performance of the knee joint movement. The purpose of this study was to investigate the influence of harvesting the patellar tendon during anterior cruciate ligament (ACL) reconstruction and the associated patellar tendon scar tissue development on the EMD of the rectus femoris (RF) and vastus medialis (VM) muscles. Seventeen patients who underwent an ACL reconstruction using the medial third of the patellar tendon were divided in two groups based upon their post-operative time interval. Maximal voluntary contraction from the knee extensors, surface EMG activity, and ultrasonographic measurements of the patellar tendon cross-section area were obtained from both knees. Our results revealed that no significant changes for the maximal voluntary contraction of the knee extensors and for the EMD of the RF and the VM muscles due to patellar scar tissue development after harvesting the tendon for ACL reconstruction. The EMD, as a component of the stretch reflex, is important for the utilization of the stored energy in the series elastic component and thus, optimal sports performance. However, from our results, it can be implied that the ACL reconstruction using a patellar tendon graft would not impair sports performance as far as EMD is concerned.

  11. Muscles, Ligaments and Tendons Journal – Basic principles and recommendations in clinical and field Science Research: 2016 Update

    PubMed Central

    Padulo, Johnny; Oliva, Francesco; Frizziero, Antonio; Maffulli, Nicola

    2016-01-01

    Summary The proper design and implementation of a study as well as a balanced and well-supported evaluation and interpretation of its main findings are of crucial importance when reporting and disseminating research. Also accountability, funding acknowledgement and adequately declaring any conflict of interest play a major role in science. Since the Muscles, Ligaments and Tendons Journal (MLTJ) is committed to the highest scientific and ethical standards, we encourage all Authors to take into account and to comply, as much as possible, to the contents and issues discussed in this official editorial. This could be useful for improving the quality of the manuscripts, as well as to stimulate interest and debate and to promote constructive change, reflecting upon uses and misuses within our disciplines belonging to the field of “Clinical and Sport - Science Research”. PMID:27331026

  12. Tendon repair

    MedlinePlus

    Repair of tendon ... Tendon repair can be performed using: Local anesthesia (the immediate area of the surgery is pain-free) ... a cut on the skin over the injured tendon. The damaged or torn ends of the tendon ...

  13. Allograft Replacement for Absent Native Tissue

    PubMed Central

    Chaudhury, Salma; Wanivenhaus, Florian; Fox, Alice J.; Warren, Russell F.; Doyle, Maureen; Rodeo, Scott A.

    2013-01-01

    Context: Structural instability due to poor soft tissue quality often requires augmentation. Allografts are important biological substitutes that are used for the symptomatic patient in the reconstruction of deficient ligaments, tendons, menisci, and osteochondral defects. Interest in the clinical application of allografts has arisen from the demand to obtain stable anatomy with restoration of function and protection against additional injury, particularly for high-demand patients who participate in sports. Traditionally, allografts were employed to reinforce weakened tissue. However, they can also be employed to substitute deficient or functionally absent tissue, particularly in the sports medicine setting. Objective: This article presents a series of 6 cases that utilized allografts to restore functionally deficient anatomic architecture, rather than just simply augmenting the degenerated or damaged native tissue. Detailed discussions are presented of the use of allografts as a successful treatment strategy to replace functionally weakened tissue, often after failed primary repairs. PMID:24427387

  14. Tendon Transfers for Combined Peripheral Nerve Injuries.

    PubMed

    Makarewich, Christopher A; Hutchinson, Douglas T

    2016-08-01

    Combined peripheral nerve injuries present a unique set of challenges to the hand surgeon when considering tendon transfers. They are often associated with severe soft tissue trauma, including lacerations to remaining innervated muscles and tendons, significant scar formation, and substantial sensory loss. In the case of combined nerve injuries, there are typically fewer options for tendon transfers due to fewer tendons of shared function that are expendable as well as associated injuries to tendon or muscle bellies. As such, careful preoperative planning must be performed to make the most of remaining muscle tendon units. PMID:27387081

  15. Does Gracilis Tendon Harvest During ACL Reconstruction with a Hamstring Autograft Affect Torque of Muscles Responsible for Shin Rotation?

    PubMed Central

    Królikowska, Aleksandra; Czamara, Andrzej; Kentel, Maciej

    2015-01-01

    Background A growing body of evidence indicates that in patients after anterior cruciate ligament reconstruction (ACLR) with a combined semitendinosus and gracilis (STGR) graft there are large deficits in the internal rotation strength, which has led some authors to recommend harvest of only ST tendon whenever possible. The purpose of this study was to assess the isometric (IT) and peak torque (PT) of the muscles responsible for shin rotation in patients after ACLR with an ST or with an STGR graft. Material/Methods Twenty patients with an ST graft and 20 patients with a combined STGR graft underwent a 6-month postoperative rehabilitation program after ACLR. At the end of the rehabilitation program, the IT and PT of the muscles responsible for internal (IR) and external rotation (ER) of the shin were measured. The results were compared to the results of a control group. Additionally, to determine the reliability of the dynamometer for clinical research, a test-retest assessment was performed. Results There were no statistically significant differences between the 3 groups of participants. Nevertheless, in the STGR group there was a statistically significant difference between the IT of muscles internally rotating the shin in the involved knee and uninvolved knee at 25° of the internal shin rotation. Conclusions Comparison of IT and PT measurements performed after 24 weeks of postoperative rehabilitation generally showed no differences between patients after ACLR with the use of ST graft and patients who received a combination graft consisting of STGR. Nevertheless, there was an influence of GR harvest on internal shin rotation torque at a deep internal rotation angle. PMID:26190033

  16. Three-Dimensional Gait Analysis Following Achilles Tendon Rupture With Nonsurgical Treatment Reveals Long-Term Deficiencies in Muscle Strength and Function

    PubMed Central

    Tengman, Tine; Riad, Jacques

    2013-01-01

    Background: Precise long-term assessment of movement and physical function following Achilles tendon rupture is required for the development and evaluation of treatment, including different regimens of physical therapy. Purpose: To assess intermediate-term (<10 years by conventional thinking) objective measures of physical function following Achilles tendon rupture treated nonsurgically and to compare these with self-reported measures of physical function. Study Design: Cross-sectional study; Level of evidence, 3. Methods: Two to 5 years after Achilles tendon rupture, 9 women and 43 men (mean age, 49.2 years; range, 26-68 years) were assessed by physical examination, performance of 1-legged jumps, and 3-dimensional gait analysis (including calculation of muscle work). Self-reported scores for foot function (Achilles tendon rupture score) and level of physical activity were collected. Twenty age- and sex-matched controls were assessed in the same manner. Results: Physical examination of patients with the knee extended revealed 11.1° of dorsiflexion on the injured side and 9.2° on the uninjured side (P = .020), indicating gastrocnemius muscle lengthening. The 1-legged jump distance was shorter on the injured side (89.5 vs 96.2 cm; P < .001). Gait analysis showed higher peak dorsiflexion (14.3° vs 13.3°; P = .016) and lower concentric (positive) plantar flexor work (16.6 vs 19.9 J/kg; P = .001) in the ankle on the uninjured side. At the same time, eccentric (negative) dorsiflexor work was higher on the injured side (13.2 vs 11.9 J/kg; P = .010). Self-perceived foot function and physical activity were lower in patients than in healthy controls (mean Achilles tendon rupture score, 78.6 and 99.8, respectively). Conclusion: Nonsurgically treated patients with Achilles tendon rupture showed signs of both anatomic and functional lengthening of the tendon. Attenuated muscle strength and function were present during walking as long as 2 to 5 years after rupture, as

  17. Contribution of calf muscle-tendon properties to single-leg stance ability in the absence of visual feedback in relation to ageing.

    PubMed

    Onambélé, Gladys L; Narici, Marco V; Rejc, Enrico; Maganaris, Constantinos N

    2007-09-01

    We tested the hypothesis that the importance of calf muscle-tendon properties for maintaining balance during single-leg stance increases in the absence of visual feedback. Trial duration, centre of pressure displacement normalized for trial duration (nD), electromyographic (EMG) activity of the main ankle plantarflexors and dorsiflexors, and ground reaction forces (F(P)), were measured in 20 younger (aged 18+/-1 years; mean+/-S.E.M.) and 28 older (aged 68+/-1 years) healthy participants during single-leg stance in eyes-open (EO) and eyes-closed (EC) conditions. Plantarflexor muscle strength, activation capacity and tendon stiffness were assessed by dynamometry, electrical stimulation and ultrasonography, respectively. Muscle-tendon characteristics in the older participants were up to 55% (P<0.0001) lower compared with their younger counterparts. Trial duration, F(P), nD and EMG changed in EC compared with EO by 21% and up to approximately 4.6 times (P<0.01) in the two population groups. Multiple linear regression with age and the three muscle-tendon properties showed a substantial increment in EC compared to EO for trial duration (R(2)=0.86 versus R(2)=0.72), but a similarity for nD (R(2)=0.36 versus R(2)=0.33). These results suggest that factors other than the ones that we examined become important when steadiness rather than stance duration is the object of single-leg stance in the absence of vision.

  18. Possible involvement of IGF-1 signaling on compensatory growth of the infraspinatus muscle induced by the supraspinatus tendon detachment of rat shoulder.

    PubMed

    Ichinose, Tsuyoshi; Lesmana, Ronny; Yamamoto, Atsushi; Kobayashi, Tsutomu; Shitara, Hitoshi; Shimoyama, Daisuke; Takatsuru, Yusuke; Iwasaki, Toshiharu; Shimokawa, Noriaki; Takagishi, Kenji; Koibuchi, Noriyuki

    2014-01-01

    A rotator cuff tear (RCT) is a common musculoskeletal disorder among elderly people. RCT is often treated conservatively for functional compensation by the remaining muscles. However, the mode of such compensation after RCT has not yet been fully understood. Here, we used the RCT rat model to investigate the compensatory process in the remaining muscles. The involvement of insulin-like growth factor 1 (IGF-1)/Akt signaling which potentially contributes to the muscle growth was also examined. The RCT made by transecting the supraspinatus (SSP) tendon resulted in atrophy of the SSP muscle. The remaining infraspinatus (ISP) muscle weight increased rapidly after a transient decrease (3 days), which could be induced by posttraumatic immobilization. The IGF-1 mRNA levels increased transiently at 7 days followed by a gradual increase thereafter in the ISP muscle, and those of IGF-1 receptor mRNA significantly increased after 3 days. IGF-1 protein levels biphasically increased (3 and 14 days), then gradually decreased thereafter. The IGF-1 protein levels tended to show a negative correlation with IGF-1 mRNA levels. These levels also showed a negative correlation with the ISP muscle weight, indicating that the increase in IGF-1 secretion may contribute to the ISP muscle growth. The pAkt/Akt protein ratio decreased transiently by 14 days, but recovered later. The IGF-1 protein levels were negatively correlated with the pAkt/Akt ratio. These results indicate that transection of the SSP tendon activates IGF-1/Akt signaling in the remaining ISP muscle for structural compensation. Thus, the remaining muscles after RCT can be a target for rehabilitation through the activation of IGF-1/Akt signaling. PMID:24744876

  19. Fresh-frozen Complete Extensor Mechanism Allograft versus Autograft Reconstruction in Rabbits

    PubMed Central

    Chen, Guanyin; Zhang, Hongtao; Ma, Qiong; Zhao, Jian; Zhang, Yinglong; Fan, Qingyu; Ma, Baoan

    2016-01-01

    Different clinical results have been reported in the repair of extensor mechanism disruption using fresh-frozen complete extensor mechanism (CEM) allograft, creating a need for a better understanding of fresh-frozen CME allograft reconstruction. Here, we perform histological and biomechanical analyses of fresh-frozen CEM allograft or autograft reconstruction in an in vivo rabbit model. Our histological results show complete incorporation of the quadriceps tendon into the host tissues, patellar survival and total integration of the allograft tibia, with relatively fewer osteocytes, into the host tibia. Vascularity and cellularity are reduced and delayed in the allograft but exhibit similar distributions to those in the autograft. The infrapatellar fat pad provides the main blood supply, and the lowest cellularity is observed in the patellar tendon close to the tibia in both the allograft and autograft. The biomechanical properties of the junction of quadriceps tendon and host tissues and those of the allograft patellar tendon are completely and considerably restored, respectively. Therefore, fresh-frozen CEM allograft reconstruction is viable, but the distal patellar tendon and the tibial block may be the weak links of the reconstruction. These findings provide new insight into the use of allograft in repairing disruption of the extensor mechanism. PMID:26911538

  20. Correlation between anthropometric data and length and thickness of the tendons of the semitendinosus and gracilis muscles used for grafts in reconstruction of the anterior cruciate ligament☆

    PubMed Central

    Pereira, Rafael Noschang; Karam, Francisco Consoli; Schwanke, Roberto Luís; Millman, Rubens; Foletto, Zilmar Minetto; Schwanke, Carla Helena Augustin

    2016-01-01

    Objective Preoperative estimation of the length and diameter of the semitendinosus (ST) and gracilis (G) tendons can assist surgeons and allow them to have the opportunity to choose alternative grafts. The aim of this study was to investigate whether anthropometric measurements such as height, weight and body mass index (BMI) or the patient's age and sex have any correlation with the thickness and the length of ST and G tendons. Methods Data were gathered from 64 patients who underwent the surgical procedure of anterior cruciate ligament reconstruction using the tendons of the ST and G muscles as grafts, between June 2012 and August 2013. Variables such as age, sex, weight, height, body mass index (BMI) and length and diameter of the tendons of the ST and G muscles were analyzed. Results There was a positive correlation between the height and total diameter of the quadruple graft (r = 0.254; p = 0.043), total length of the ST tendon (r = 0.450; p < 0.01), diameter of the double ST (r = 0.270; p = 0.031), triple ST (r = 0.347; p = 0.005), length of G tendon (r = 0.249; p = 0.047) and diameter of the double-G (r = 0.258; p = 0.039). However, age (r = -0.015; p = 0.908), weight (r = 0.165; p = 0.193) and body mass index (r = 0.012; p = 0.926) showed no correlation. Conclusion Our results show that age, weight and BMI did not correlate with the diameter and length of the graft, while the height had a positive correlation with the total length of the flexor tendons and the diameter of the graft from the flexors (ST and G). PMID:27069886

  1. ARTHROSCOPIC REPAIR OF SMALL AND MEDIUM TEARS OF THE SUPRASPINATUS MUSCLE TENDON: EVALUATION OF THE CLINICAL AND FUNCTIONAL OUTCOMES AFTER TWO YEARS OF FOLLOW-UP

    PubMed Central

    Ikemoto, Roberto Yukio; Murachovsky, Joel; Nascimento, Luís Gustavo Prata; Bueno, Rogério Serpone; Almeida, Luis Henrique; Strose, Eric; Castiglia, Marcello Teixeira

    2015-01-01

    Objective: To evaluate the clinical and functional outcomes from arthroscopic repairs on small and medium-sized tears of the supraspinatus muscle tendon. Methods: 129 cases of isolated small and medium tears of the supraspinatus muscle tendon were evaluated retrospectively. The average duration of pain was 29 months. The average joint range of motion comprised active elevation of 136°, lateral rotation of 58° and medial rotation at T12 level; and the preoperative functional UCLA score averaged 17 points. In all the cases, complete repair could be achieved. Results: The average score on the UCLA functional scale in the postoperative period was 32 points. The average length of follow-up was 39 months. Seventy-five cases (58%) had excellent results and 42 (32%) had good results. The average final active elevation was 156° with an average gain of 20°, and the average final lateral rotation was 57° with an average gain of 9°. Both of these were statistically significant (P < 0.05). The patients who underwent tenotomy of the long head of the biceps (LHB), with or without tenodesis, did not present statistically inferior functional outcomes, in comparison with the patients who only underwent decompression and lesion repair (P = 1.00). Fourteen cases (10.8%) presented complications during the postoperative period. Six (4.6%) developed adhesive capsulitis and four (3.1%) presented re-rupture of the tendon, proven by means of magnetic resonance imaging. Conclusions: Arthroscopic repair of small and medium tears of the supraspinatus muscle tendon provided a functional clinical improvement, with good and excellent results in 90% of the cases. PMID:27047846

  2. Autologous hamstring tendon used for revision of quadiceps tendon tears.

    PubMed

    McCormick, Frank; Nwachukwu, Benedict U; Kim, Jaehon; Martin, Scott D

    2013-04-01

    A paucity of literature exists on quadriceps tendon reruptures. Failed quadriceps tendon repair can cause significant morbidity and disability. Surgical management of quadriceps tendon rerupture can be challenging due to tissue degeneration, tendon retraction, muscle atrophy, and poor bone fixation. A lack of guidance in the literature exists on the appropriate surgical techniques for managing quadriceps tendon reruptures.This article describes the case of a male recreational athlete with a failed primary quadriceps tendon repair who presented 10 months after rerupture. Examination was significant for morbid obesity, assisted ambulation, and a significant defect at the superior pole of the patella on the affected side. Intraoperative findings were consistent with a 2.0- to 4.5-cm tendon defect across the extensor mechanism with complete retinaculi tears. The authors performed a novel surgical approach for revision of quadriceps tears using a bilateral hamstring autograft through a quadriceps tendon weave and a transosseous patellar repair. Tendon length was restored, and extensor mechanism tension was reapproximated. Postoperatively, the patient achieved a good outcome and had returned to full, painless, sport participation at 2-year follow-up.This surgical technique is suitable for revision quadriceps tendon repairs of large tendon gap defects, repairs desiring tendon-to-bone in-growth, and repairs requiring large-force transmission across the repair.

  3. Muscle-tendon unit scaling methods of Hill-type musculoskeletal models: An overview.

    PubMed

    Heinen, Frederik; Lund, Morten E; Rasmussen, John; de Zee, Mark

    2016-10-01

    This article gives an overview of the state of the art in scaling methods of generic Hill-type muscle model parameters in view of different applications and implementation of experimental data. This article establishes the requirements used to alter a generic model toward subject-specific musculoskeletal models. This article aims to improve model transparency by a structured description of scaling methods and the associated limitations in musculoskeletal models and highlight the importance of selecting a scaling method supporting the purpose of the model.

  4. The effect of tendon surface treatment on cell attachment for potential enhancement of tendon graft healing: an ex vivo model.

    PubMed

    Hashimoto, Takahiro; Sun, Yu-Long; An, Kai-Nan; Amadio, Peter C; Zhao, Chunfeng

    2012-12-01

    For both tendon allografts and autografts, the surface, initially optimized for gliding, may not be ideal to facilitate tissue integration for graft healing to host tendon or bone. As a prelude to studying tendon-bone integration, we investigated the effect of surface treatments with trypsin or mechanical abrasion on cell attachment to the tendon surface in a canine ex vivo intrasynovial tendon tissue culture model. Intrasynovial tendon allograft surfaces were seeded with cells after the following treatments: (1) no treatment, (2) mechanical abrasion, (3) trypsin, and (4) abrasion and trypsin. The area covered by cells was determined using confocal laser microscopy at one and two weeks. Results were compared to untreated extrasynovial tendon. Additional tendons were characterized with scanning electron microscopy. Tendons with trypsin treatment had significantly more surface coverage with cells than the other groups, after both one and two weeks of culture. In terms of the cellular shape and size, cells on tendons with trypsin treatment spread more and were more polygonal in shape, whereas tendons with mechanical abrasion with/without trypsin treatment contained smaller, more spindle-like cells. Surface roughening can affect cell behavior with topographical stimulation. Trypsin surface digestion exposes a mesh-like structure on the tendon surface, which could enhance cell adherence and, possibly, tendon/bone healing.

  5. RECONSTRUCTION OF THE ANTERIOR CRUCIATE LIGAMENT WITH THE CENTRAL THIRD OF THE QUADRICEPS MUSCLE TENDON: ANALYSIS OF 10-YEAR RESULTS

    PubMed Central

    Guimarães, Marcus Valladares; Junior, Lúcio Honório de Carvalho; Terra, Dalton Lopes

    2015-01-01

    Objective: Assess clinical results using two different protocols, 10 years after ACL reconstruction surgery with the central third of quadriceps muscle tendon (QT). Method: Between November /1997 and April/1998, 25 patients were submitted to 25 ACL reconstructions with QT by transtibial technique. The bone portion of the graft was fixated on femoral tunnel with interference screw and the tendinous portion of tibial tunnel with screw with washer. Two patients injured the new when playing soccer. Six patients were not available for follow-up (24%). Seventeen patients were evaluated, 15 men and two women, with mean age at surgery time of 28.53 ± 6.64 years. All patients were examined at six months, one year, and ten years after surgery. Clinical evaluation was made by the Lysholm scale, and the knee evaluation, with the Hospital for Special Surgery scale. Results: The patients had their injuries operated after 9.87 ± 14.42 months of the accident. According to Lysholm scale, the results at the end of the first year were 98.71 ± 2.47 and, after 10 years, 97.35 ± 3.12. Using the Hospital for Special Surgery scale, the mean score was 95.07 ± 5.23 in one year, and 94.87 ± 4.16 in 10 years. All patients returned to their professional activities with the same previous status. Fifteen (88.24%) patients were able to return to their sports activities, one by modifying the practice, while another one switched to another sport. No patient complained of pain on the donor area in the medium and long term. The sports return rate was excellent, and no changes were found on the femoropatellar joint. PMID:27022511

  6. Comparison of the validity of Hill and Huxley muscle-tendon complex models using experimental data obtained from rat m. soleus in situ.

    PubMed

    Lemaire, Koen K; Baan, Guus C; Jaspers, Richard T; van Soest, A J Knoek

    2016-04-01

    The relationship between mechanical and metabolic behaviour in the widely used Hill muscle-tendon complex (MTC) model is not straightforward, whereas this is an integral part of the Huxley model. In this study, we assessed to what extent Huxley- and Hill-type MTC models yield adequate predictions of mechanical muscle behaviour during stretch-shortening cycles (SSCs). In fully anaesthetized male Wistar rats (N=3), m. soleus was dissected completely free, except for the insertion. Cuff electrodes were placed over the n. ischiadicus. The distal end of the tendon was connected to a servo motor, via a force transducer. The setup allowed for full control over muscle stimulation and length, while force was measured. Quick-release and isovelocity contractions (part 1), and SSCs (part 2) were imposed. Simulations of part 2 were made with both a Hill and a Huxley MTC model, using parameter values determined from part 1. Modifications to the classic two-state Huxley model were made to incorporate series elasticity, activation dynamics, and active and passive force-length relationships. Results were similar for all rats. Fitting of the free parameters to the data of part 1 was near perfect (R(2)>0.97). During SSCs, predicted peak force and force during relaxation deviated from the experimental data for both models. Overall, both models yielded similarly adequate predictions of the experimental data. We conclude that Huxley and Hill MTC models are equally valid with respect to mechanical behaviour.

  7. Effects of Sacrificing Tensor Tympani Muscle Tendon When Manubrium of Malleus Is Foreshortened in Type I Tympanoplasty

    PubMed Central

    Vadiya, Sohil

    2015-01-01

    The current study aims at observing effects of sacrificing the tensor tympani tendon when manubrium of malleus is foreshortened or retracted on graft uptake, hearing improvement, and occurrence of complications if any during type I tympanoplasty surgery for central perforations. 42 patients were included in group A where the tensor tendon was sectioned and 42 patients were included in group B where the tensor tympani tendon was retained and kept intact. Graft uptake rates are very good in both groups but hearing improvement was found significantly better in group A than group B. No unusual or undesired complications were seen in any of the cases. Sectioning of tensor tympani tendon is safe and effective procedure in cases where manubrium is foreshortened. PMID:26697069

  8. 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.

  9. Isokinetic dynamometer evaluation of the effects of early thigh diameter difference on thigh muscle strength in patients undergoing anterior cruciate ligament reconstruction with hamstring tendon graft.

    PubMed

    Kılınç, Bekir Eray; Kara, Adnan; Camur, Savas; Oc, Yunus; Celik, Haluk

    2015-04-01

    After anterior cruciate ligament (ACL) reconstruction, which muscle groups are more affected from frequently developing thigh muscle atrophy is a matter of debate. We evaluate the effect of thigh circumference difference between patients' knees who were administered the ACL reconstruction with hamstring tendon autograft and intact knees, on torque between the hamstring and quadriceps muscles. Fifty-five patients at least 6 months follow-up period available were included in our study. Power measurements of quadriceps and hamstring muscle groups in patients' extremities were done by using isokinetic dynamometer. The maximum torque values at 60°/sec, 240°/sec in frequency, positions of flexion and extension were determined. In accordance with our findings it is still possible to encounter the thigh atrophy in average 28 months after ACL reconstruction surgery even under physical rehabilitation programs and appropriate follow-up. It is inevitable for the clinician to consider these changes in diagnosis and rehabilitation stages. It can't be ignored that muscle weakness mechanisms developing in the thigh circumference vary according to the thigh muscle group and knee flexors play an important role in thigh atrophy when determining an appropriate rehabilitation program after reconstruction application.

  10. Isokinetic dynamometer evaluation of the effects of early thigh diameter difference on thigh muscle strength in patients undergoing anterior cruciate ligament reconstruction with hamstring tendon graft

    PubMed Central

    Kılınç, Bekir Eray; Kara, Adnan; Camur, Savas; Oc, Yunus; Celik, Haluk

    2015-01-01

    After anterior cruciate ligament (ACL) reconstruction, which muscle groups are more affected from frequently developing thigh muscle atrophy is a matter of debate. We evaluate the effect of thigh circumference difference between patients’ knees who were administered the ACL reconstruction with hamstring tendon autograft and intact knees, on torque between the hamstring and quadriceps muscles. Fifty-five patients at least 6 months follow-up period available were included in our study. Power measurements of quadriceps and hamstring muscle groups in patients’ extremities were done by using isokinetic dynamometer. The maximum torque values at 60°/sec, 240°/sec in frequency, positions of flexion and extension were determined. In accordance with our findings it is still possible to encounter the thigh atrophy in average 28 months after ACL reconstruction surgery even under physical rehabilitation programs and appropriate follow-up. It is inevitable for the clinician to consider these changes in diagnosis and rehabilitation stages. It can’t be ignored that muscle weakness mechanisms developing in the thigh circumference vary according to the thigh muscle group and knee flexors play an important role in thigh atrophy when determining an appropriate rehabilitation program after reconstruction application. PMID:25960982

  11. Tendon Innervation.

    PubMed

    Ackermann, Paul W; Salo, Paul; Hart, David A

    2016-01-01

    The regulation of tendon metabolism including the responses to loading is far from being well understood. During the last decade, however, accumulating data show that tendon innervation in addition to afferent functions, via efferent pathways has a regulatory role in tendon homeostasis via a wide range of neuromediators, which coordinate metabolic and neuro-inflammatory pathways.Innervation of intact healthy tendons is localized in the surrounding structures, i.e paratenon, endotenon and epitenon, whereas the tendon proper is practically devoid of neuronal supply. This anatomical finding reflects that the tendon metabolism is regulated from the tendon envelope, i.e. interfascicular matrix (see Chap. 1 ).Tendon innervation after injury and during repair, however, is found as extensive nerve ingrowth into the tendon proper, followed by a time-dependent emergence of different neuronal mediators, which amplify and fine-tune inflammatory and metabolic pathways in tendon regeneration. After healing nerve fibers retract to the tendon envelope.In tendinopathy innervation has been identified to consist of excessive and protracted nerve ingrowth in the tendon proper, suggesting pro-inflammatory, nociceptive and hypertrophic (degenerative) tissue responses.In metabolic disorders such as eg. diabetes impaired tendon healing has been established to be related to dysregulation of neuronal growth factors.Targeted approaches to the peripheral nervous system including neuronal mediators and their receptors may prove to be effective therapies for painful, degenerative and traumatic tendon disorders. PMID:27535247

  12. Effect of repeated freezing-thawing on the Achilles tendon of rabbits.

    PubMed

    Chen, Lianxu; Wu, Yanping; Yu, Jiakuo; Jiao, Zhaode; Ao, Yingfang; Yu, Changlong; Wang, Jianquan; Cui, Guoqing

    2011-06-01

    The increased use of allograft tissue in the reconstruction of anterior cruciate ligament has brought more focus to the effect of storage and treatment on allograft. The purpose of this study was to observe the effect of histology and biomechanics on Achilles tendon in rabbits through repeated freezing-thawing before allograft tendon transplantation. Rabbit Achilles tendons were harvested and processed according to the manufacture's protocol of tissue bank, and freezing-thawing was repeated three times (group 1) and ten times (group 2). Those received only one cycle were used as controls. Then, tendons in each group were selected randomly to make for histological observations and biomechanics test. Histological observation showed that the following changes happened as the number of freezing-thawing increased: the arrangement of tendon bundles and collagen fibrils became disordered until ruptured, cells disrupted and apparent gaps appeared between tendon bundle because the formation of ice crystals. There were significant differences between the experimental and control groups in the values of maximum load, energy of maximum load and maximum stress, whereas no significant differences existed in other values such as stiffness, maximum strain, elastic modulus, and energy density. Therefore, repeated freezing-thawing had histological and biomechanical effect on Achilles tendon in rabbits before allograft tendon transplantation. This indicates that cautions should be taken in the repeated freezing-thawing preparation of allograft tendons in clinical application.

  13. Autograft Versus Nonirradiated Allograft Tissue for Anterior Cruciate Ligament Reconstruction

    PubMed Central

    Mariscalco, Michael W.; Magnussen, Robert A.; Mehta, Divyesh; Hewett, Timothy E.; Flanigan, David C.; Kaeding, Christopher C.

    2014-01-01

    Background An autograft has traditionally been the gold standard for anterior cruciate ligament reconstruction (ACLR), but the use of allograft tissue has increased in recent years. While numerous studies have demonstrated that irradiated allografts are associated with increased failure rates, some report excellent results after ACLR with nonirradiated allografts. The purpose of this systematic review was to determine whether the use of nonirradiated allograft tissue is associated with poorer outcomes when compared with autografts. Hypothesis Patients undergoing ACLR with autografts versus nonirradiated allografts will demonstrate no significant differences in graft failure risk, laxity on postoperative physical examination, or differences in patient-oriented outcome scores. Study Design Systematic review. Methods A systematic review was performed to identify prospective or retrospective comparative studies (evidence level 1, 2, or 3) of autografts versus nonirradiated allografts for ACLR. Outcome data included graft failure based on clinical findings and instrumented laxity, postoperative laxity on physical examination, and patient-reported outcome scores. Studies were excluded if they did not specify whether the allograft had been irradiated. Quality assessment and data extraction were performed by 2 examiners. Results Nine studies comparing autografts and nonirradiated allografts were included. Six of the 9 studies compared bone– patellar tendon–bone (BPTB) autografts with BPTB allografts. Two studies compared hamstring tendon autografts to hamstring tendon allografts, and 1 study compared hamstring tendon autografts to tibialis anterior allografts. The mean patient age in 7 of 9 studies ranged from 24.5 to 32 years, with 1 study including only patients older than 40 years and another not reporting patient age. The mean follow-up duration was 24 to 94 months. Six of 9 studies reported clinical graft failure rates, 8 of 9 reported postoperative instrumented

  14. Adaptation of the tendon to mechanical usage.

    PubMed

    Reeves, N D

    2006-01-01

    Tendons primarily function as contractile force transmitters, but their mechanical properties may change dependent upon their level of mechanical usage. Using an ultrasound-based technique we have assessed tendon mechanical properties in vivo in a number of conditions representing different levels of mechanical usage. Ageing alters tendon mechanical properties; stiffness and modulus were lower in older adults by 10 and 14%, respectively, compared to young adults. Increased levels of exercise loading in old age can however partly reverse this process, as tendon stiffness and modulus were found to increase by 65 and 69%, respectively. Complete unloading due to bed rest or spinal cord injury both reduce tendon stiffness and modulus, however, only chronic unloading due to spinal cord injury seems to cause tendon atrophy. Alterations in tendon mechanical properties due to changes in the levels loading have implications for the speed of force transmission, the muscle's operating range and the likelihood of tendon strain injury.

  15. Hamstring tendon harvesting--Effect of harvester on tendon characteristics and soft tissue disruption; cadaver study.

    PubMed

    Charalambous, C P; Alvi, F; Phaltankar, P; Gagey, O

    2009-06-01

    The purpose of this study was to determine whether the type of hamstring tendon harvester used can influence harvested tendon characteristics and soft tissue disruption. We compared two different types of tendon harvesters with regard to the length of tendon obtained and soft tissue disruption during hamstring tendon harvesting. Thirty six semitendinosus and gracilis tendons were harvested using either a closed stripper or a blade harvester in 18 paired knees from nine human fresh cadavers. Use of the blade harvester gave longer lengths of usable tendon whilst minimising the stripping of muscle and of any non-usable tendon. Our results suggest that the type of harvester per se can influence the length of tendon harvested as well as soft tissue disruption. Requesting such data from the industry prior to deciding which harvester to use seems desirable.

  16. 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

  17. Percutaneous techniques for tendon transfers in the foot and ankle.

    PubMed

    Panchbhavi, Vinod Kumar

    2014-03-01

    Tendon transfer procedures are useful for replacing a dysfunctional or diseased tendon or for restoring muscle imbalance. The tendon to be transferred is harvested as distal as is necessary to provide adequate length for rerouting and attachment at the different site. The harvesting of tendon itself can be attained using an open surgical approach or minimally invasive percutaneous techniques that limit surgical exposure. This article describes percutaneous techniques for tendon transfer procedures used to address foot and ankle disorders. PMID:24548514

  18. What is the best candidate allograft for ACL reconstruction? An in vitro mechanical and histologic study in a canine model.

    PubMed

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

    2015-07-16

    The knee joint is generally characterized by very low friction and high wear resistance. Several previous studies have compared ACL with the commonly used allografts from tensile properties perspective. No study has reported about the graft tendons from a frictional perspective, which is an important parameter for ACL functional performance. Twenty hind legs were used to harvest FDP tendon, ACL, ACH, and patellar tendon. Samples were evaluated with surface friction testing, indentation testing for tendon compressive moduli, lubricin immunohistochemistry, and histologic analysis. Frictional force of FDP tendon and ACL was significantly less than that of patellar tendon and ACH at first and fifth cycles. At the tenth cycle, the FDP tendon, ACL, and ACH showed significantly less frictional force than patellar tendon; after 100 cycles, the FDP tendon and ACL showed significantly less frictional force than patellar tendon. The compressive moduli of the FDP tendon, ACL, and ACH were significantly greater than that of patellar tendon. Histologic results showed that FDP tendon and ACL had a smooth surface with a thin layer of epitenon cells; patellar tendon and ACH had a rough surface and a layer of paratenon. Lubricin was found on the surface and extracellular matrix of FDP tendon and ACL. There was only limited lubricin expression on the surface and extracellular matrix of the ACH and patellar tendon. The FDP tendon has friction force and lubricin expression similar to those of native ACL. However, patellar tendon and ACH show higher friction force and less lubricin expression than ACL. PMID:25981102

  19. Reconstruction of chronic patellar tendon rupture using graft from contralateral patella graft together with reinforcement from flexor tendons. Case report.

    PubMed

    Frois Temponi, Eduardo; de Carvalho, Lúcio Honório; da Silva Bernardes, Cláudio Otávio; Presses Teixeira, Bruno

    2016-01-01

    Chronic patellar tendon rupture is a rare disabling injury that is technically difficult to repair. The true prevalence of this injury is unknown. Delayed reconstruction of chronic patellar tendon rupture has yielded suboptimal clinical and functional results. Many different surgical methods for reconstruction of chronic patellar tendon injury have been reported. In this report, we present a case with chronic patellar tendon injury that was addressed using a technique that had not previously been described in the literature, through combining procedures that had been described separately. The reconstruction method presented in this article has the advantages of being easy and reproducible, without a requirement of allografts.

  20. Anatomic anterior cruciate ligament reconstruction with quadriceps tendon autograft.

    PubMed

    Rabuck, Stephen J; Musahl, Volker; Fu, Freddie H; West, Robin V

    2013-01-01

    A multitude of graft options exist including both allograft and autograft sources for reconstruction of the anterior cruciate ligament. With recent concerns regarding the early graft failure and cost-effectiveness of allograft sources, more attention has been directed toward autograft options. However, autograft harvest has been associated with specific morbidity that can result in suboptimal outcomes. The quadriceps tendon is an excellent biomechanical and biologic option.

  1. On the mechanical function of tendon.

    PubMed

    Kafka, V; Jírová, J; Smetana, V

    1995-01-01

    A mesoscopic approach is followed for mathematical modelling of the specific deformation properties of tendon. The approach starts from our general concept of modelling mechanical behaviour of heterogeneous media and assumes that the structure of tendon is optimized in such a way that it enables its adjacent muscle to work with a constant performance in the course of increasing loading (acting like a gearbox in a car). The model based on this assumption gives results that are in a very good accordance with observed properties of tendons. Clinical experience reveals that if this function of tendon is violated pathological changes appear in the respective muscle. RELEVANCE: Clarification and mathematical modelling of the mechanical function of tendon is of intellectual interest in its own right, but it is important also for cautioning surgeons against unnecessary violation of this function, and for tissue engineering aspects if tendon must be replaced.

  2. A Computer-Controlled, MR-compatible Foot-Pedal Device to Study Dynamics of the Muscle Tendon Complex under Isometric, Concentric and Eccentric Contractions

    PubMed Central

    Sinha, Shantanu; Shin, David D.; Hodgson, John A.; Kinugasa, Ryuta; Edgerton, V. Reggie

    2013-01-01

    Purpose To design a computer-controlled, MR compatible foot pedal device that allows in vivo mapping of changes in morphology and in strain of different musculoskeletal components of the lower leg under passive, isometric, concentric and eccentric contractions. Materials and Methods A programmable servo-motor in the control room pumped hydraulic fluid to rotate a foot-pedal inside the magnet. Towards validating the performance of the device, six subjects were imaged with gated velocity-encoded phase-contrast (VE-PC) imaging to investigate dynamics of muscle and aponeurotic structures. Results Artifact-free VE-PC imaging clearly delineated different muscle compartments by differences in distribution of mechanical strains. High repeatability of contraction cycles allowed establishing that fascicles lengthened 6.1% more during passive compared to eccentric contractions. Aponeurosis separation during passive (range between three locations: −2.6~1.3 mm) and active (range: −2.4 ~1.6 mm) contractions were similar but significantly different from concentric (range: −0.9~3.3 mm), with proximal and distal regions showing mostly negative values for the first two modes, but positive for the last. Conclusion The device was sufficiently robust and artifact-free to accurately assess, using VE-PC imaging, physiologically important structure and dynamics of the musculo-tendon complex. PMID:22392816

  3. Micro-organisms isolated from cadaveric samples of allograft musculoskeletal tissue.

    PubMed

    Varettas, Kerry

    2013-12-01

    Allograft musculoskeletal tissue is commonly used in orthopaedic surgical procedures. Cadaveric donors of musculoskeletal tissue supply multiple allografts such as tendons, ligaments and bone. The microbiology laboratory of the South Eastern Area Laboratory Services (SEALS, Australia) has cultured cadaveric allograft musculoskeletal tissue samples for bacterial and fungal isolates since 2006. This study will retrospectively review the micro-organisms isolated over a 6-year period, 2006-2011. Swab and tissue samples were received for bioburden testing and were inoculated onto agar and/or broth culture media. Growth was obtained from 25.1 % of cadaveric allograft musculoskeletal tissue samples received. The predominant organisms isolated were coagulase-negative staphylococci and coliforms, with the heaviest bioburden recovered from the hemipelvis. The rate of bacterial and fungal isolates from cadaveric allograft musculoskeletal tissue samples is higher than that from living donors. The type of organism isolated may influence the suitability of the allograft for transplant.

  4. Tendon Differentiation on Decellularized Extracellular Matrix Under Cyclic Loading.

    PubMed

    Youngstrom, Daniel W; Barrett, Jennifer G

    2016-01-01

    Tendon bioreactors combine cells, scaffold, and mechanical stimulation to drive tissue neogenesis ex vivo. Faithful recapitulation of the native tendon microenvironment is essential for stimulating graft maturation or modeling tendon biology. As the mediator between cells and mechanical stimulation, the properties of a scaffold constitute perhaps the most essential elements in a bioreactor system. One method of achieving native scaffold properties is to process tendon allograft in a manner that removes cells without modifying structure and function: "decellularization." This chapter describes (1) production of tendon scaffolds derived from native extracellular matrix, (2) preparation of cell-laden scaffolds prior to bioreactor culture, and (3) tissue processing post-harvest for gene expression analysis. These methods may be applied for a variety of applications including graft production, cell priming prior to transplantation and basic investigations of tendon cell biology. PMID:27062597

  5. Tendon Differentiation on Decellularized Extracellular Matrix Under Cyclic Loading.

    PubMed

    Youngstrom, Daniel W; Barrett, Jennifer G

    2016-01-01

    Tendon bioreactors combine cells, scaffold, and mechanical stimulation to drive tissue neogenesis ex vivo. Faithful recapitulation of the native tendon microenvironment is essential for stimulating graft maturation or modeling tendon biology. As the mediator between cells and mechanical stimulation, the properties of a scaffold constitute perhaps the most essential elements in a bioreactor system. One method of achieving native scaffold properties is to process tendon allograft in a manner that removes cells without modifying structure and function: "decellularization." This chapter describes (1) production of tendon scaffolds derived from native extracellular matrix, (2) preparation of cell-laden scaffolds prior to bioreactor culture, and (3) tissue processing post-harvest for gene expression analysis. These methods may be applied for a variety of applications including graft production, cell priming prior to transplantation and basic investigations of tendon cell biology.

  6. Quadriceps and patellar tendon rupture.

    PubMed

    Ramseier, L E; Werner, C M L; Heinzelmann, M

    2006-06-01

    Ruptures of the patellar and/or quadriceps tendon are rare injuries that require immediate repair to re-establish knee extensor continuity and to allow early motion. We evaluated 36 consecutive patients with quadriceps or patellar tendon rupture between 1993 and 2000. There were 37 primary ruptures, 3 reruptures, 21 quadriceps and 19 patellar tendon ruptures. Follow up examination (>24 months postoperatively) included the patient's history, assessment of risk factors, clinical examination of both knees, isometric muscle strength measurements and three specific knee scores, Hospital for Special Surgery Score, Knee Society Score and Turba Score, and a short form SF-36. We evaluated 29 patients (26 men) with 33 ruptures (16 patellar tendon, 17 quadriceps tendon). Seven patients were lost to follow up. We found no difference between the range of motion and muscle strength when the injured leg was compared to the non-injured leg. Risk factors did not influence the four scores, patient satisfaction, pain, muscle strength or range of motion. Multiple injured patients had a significant reduction in muscle strength and circumference, however patient satisfaction did not differ to the non-multiple injured patient group.

  7. Immune response to nonspecific and altered tissue antigens in soft tissue allografts.

    PubMed

    Pinkowski, J L; Rodrigo, J J; Sharkey, N A; Vasseur, P B

    1996-05-01

    Soft tissue allografts have many uses in orthopaedic surgery, including knee ligament reconstruction, hand tendon surgery, shoulder instability, and rotator cuff reconstruction. The predictable biologic incorporation of soft tissue allografts without rejection or fear of disease transmission continues to be a goal of basic science researchers. A review of the current knowledge if the immune system response to donor specific, nonspecific, and altered tissue antigens in soft tissue or tendon allografts is presented. An in vitro study was done in an attempt to decrease immunogenicity of a frozen bone-ligament graft by adding irrigation with Betadine scrub solution and hydrogen peroxide to the conventional storage process of freezing. Although the irrigation with cytotoxic agents would undoubtedly further decrease immunogenicity, it also decreased stiffness and maximum load by 15%. Whether this decreased strength and stiffness would compromise the incorporation and long term success of soft tissue allografts would need to be studied by in vitro experiments.

  8. Principles of tendon transfers.

    PubMed

    Coulet, B

    2016-04-01

    Tendon transfers are carried out to restore functional deficits by rerouting the remaining intact muscles. Transfers are highly attractive in the context of hand surgery because of the possibility of restoring the patient's ability to grip. In palsy cases, tendon transfers are only used when a neurological procedure is contraindicated or has failed. The strategy used to restore function follows a common set of principles, no matter the nature of the deficit. The first step is to clearly distinguish between deficient muscles and muscles that could be transferred. Next, the type of palsy will dictate the scope of the program and the complexity of the gripping movements that can be restored. Based on this reasoning, a surgical strategy that matches the means (transferable muscles) with the objectives (functions to restore) will be established and clearly explained to the patient. Every paralyzed hand can be described using three parameters. 1) Deficient segments: wrist, thumb and long fingers; 2) mechanical performance of muscles groups being revived: high energy-wrist extension and finger flexion that require strong transfers with long excursion; low energy-wrist flexion and finger extension movements that are less demanding mechanically, because they can be accomplished through gravity alone in some cases; 3) condition of the two primary motors in the hand: extrinsics (flexors and extensors) and intrinsics (facilitator). No matter the type of palsy, the transfer surgery follows the same technical principles: exposure, release, fixation, tensioning and rehabilitation. By performing an in-depth analysis of each case and by following strict technical principles, tendon transfer surgery leads to reproducible results; this allows the surgeon to establish clear objectives for the patient preoperatively. PMID:27117119

  9. Subtotal Scapulectomy With Scapulothoracic Fusion and Local Tendon Transfer for Management of Chondrosarcoma.

    PubMed

    Schoch, Bradley; Shives, Thomas; Elhassan, Bassem

    2016-06-01

    Scapulectomy can dramatically alter glenohumeral function and the ability of patients to conduct activities of daily living. In oncologic cases, treatment of the tumor can compromise local musculature, making successful reconstruction difficult to achieve. Depending on the resection level, local musculature may be inadequate to restore shoulder range of motion and/or glenohumeral stability. Surgeons have attempted to address these issues via soft-tissue repairs, allograft replacement, and prosthetic replacement, with variable success. Outcomes are better when a greater portion of the scapula is preserved, thus saving functional rotator cuff muscle bellies. However, preservation of significant rotator cuff musculature is not routinely possible. To our knowledge, no authors in the English-language orthopaedic literature have reported on local tendon transfers as a technique to augment and reconstruct the rotator cuff in a patient with previous scapulectomy. PMID:27115794

  10. Partial tear of the quadriceps tendon in a child.

    PubMed

    Khanna, Geetika; El-Khoury, George

    2008-06-01

    We present a case of partial rupture of the quadriceps tendon in an 8-year-old girl. This is one of the youngest patients reported with a quadriceps tendon rupture, an entity seen predominantly in middle-aged people. The strength of the muscle tendon unit in a child makes tendon injuries extremely unusual as compared to apophyseal avulsions. The MR imaging findings of this unusual pediatric injury are illustrated.

  11. Acellular Nerve Allografts in Peripheral Nerve Regeneration: A Comparative Study

    PubMed Central

    Moore, Amy M.; MacEwan, Matthew; Santosa, Katherine B.; Chenard, Kristofer E.; Ray, Wilson Z.; Hunter, Daniel A.; Mackinnon, Susan E.; Johnson, Philip J.

    2011-01-01

    Background Processed nerve allografts offer a promising alternative to nerve autografts in the surgical management of peripheral nerve injuries where short deficits exist. Methods Three established models of acellular nerve allograft (cold-preserved, detergent-processed, and AxoGen® -processed nerve allografts) were compared to nerve isografts and silicone nerve guidance conduits in a 14 mm rat sciatic nerve defect. Results All acellular nerve grafts were superior to silicone nerve conduits in support of nerve regeneration. Detergent-processed allografts were similar to isografts at 6 weeks post-operatively, while AxoGen®-processed and cold-preserved allografts supported significantly fewer regenerating nerve fibers. Measurement of muscle force confirmed that detergent-processed allografts promoted isograft-equivalent levels of motor recovery 16 weeks post-operatively. All acellular allografts promoted greater amounts of motor recovery compared to silicone conduits. Conclusions These findings provide evidence that differential processing for removal of cellular constituents in preparing acellular nerve allografts affects recovery in vivo. PMID:21660979

  12. Surgical Treatment of Neglected Traumatic Quadriceps Tendon Rupture with Knee Ankylosis.

    PubMed

    Lee, Seung-Hun; Song, Eun-Kyoo; Seon, Jong-Keun; Woo, Seong-Hwan

    2016-06-01

    Quadriceps tendon rupture is an uncommon injury. This disabling condition is the result of direct or indirect trauma. It requires surgical repair to avoid poor outcomes in cases of neglected or chronic rupture. In most acute cases, simple tendon suture or reinsertion is suitable for an extensor mechanism reconstruction of the knee joint. However, chronic lesions often require a tendon graft or flap reconstruction. We report a case of a 15-year-old male who was diagnosed with a chronic quadriceps rupture with a patellar superior pole fracture. We performed quadriceps reconstruction using tibialis anterior allograft tendon and additional screw fixation to reconstruct the extensor mechanism and recover knee joint range of motion to prevent a high-level functional restriction. The treatment was difficult and limited due to neglect for 9-months that led to ankylosis accompanied with nonunion of tibial fracture. Our surgical treatment using allograft tendon resulted in a very good outcome after 30 months of follow-up.

  13. Quadriceps and patellar tendon ruptures.

    PubMed

    Lee, Dennis; Stinner, Daniel; Mir, Hassan

    2013-10-01

    The diagnosis of quadriceps and patellar tendon ruptures requires a high index of suspicion and thorough history-taking to assess for medical comorbidities that may predispose patients to tendon degeneration. Radiographic assessment with plain films supplemented by ultrasound and magnetic resonance imaging when the work-up is equivocal further aids diagnosis; however, advanced imaging is often unnecessary in patients with functional extensor mechanism deficits. Acute repair is preferred, and transpatellar bone tunnels serve as the primary form of fixation when the tendon rupture occurs at the patellar insertion, with or without augmentation depending on surgeon preference. Chronic tears and disruptions following total knee arthroplasty are special cases requiring reconstructions with allograft, synthetic mesh, or autograft. Rehabilitation protocols generally allow immediate weight-bearing with the knee locked in extension and crutch support. Limited arc motion is started early with active flexion and passive extension and then advanced progressively, followed by full active range of motion and strengthening. Complications are few but include quadriceps atrophy, knee stiffness, and rerupture. Outcomes are excellent if repair is done acutely, with poorer outcomes associated with delayed repair.

  14. Inferring Muscle-Tendon Unit Power from Ankle Joint Power during the Push-Off Phase of Human Walking: Insights from a Multiarticular EMG-Driven Model

    PubMed Central

    2016-01-01

    Introduction Inverse dynamics joint kinetics are often used to infer contributions from underlying groups of muscle-tendon units (MTUs). However, such interpretations are confounded by multiarticular (multi-joint) musculature, which can cause inverse dynamics to over- or under-estimate net MTU power. Misestimation of MTU power could lead to incorrect scientific conclusions, or to empirical estimates that misguide musculoskeletal simulations, assistive device designs, or clinical interventions. The objective of this study was to investigate the degree to which ankle joint power overestimates net plantarflexor MTU power during the Push-off phase of walking, due to the behavior of the flexor digitorum and hallucis longus (FDHL)–multiarticular MTUs crossing the ankle and metatarsophalangeal (toe) joints. Methods We performed a gait analysis study on six healthy participants, recording ground reaction forces, kinematics, and electromyography (EMG). Empirical data were input into an EMG-driven musculoskeletal model to estimate ankle power. This model enabled us to parse contributions from mono- and multi-articular MTUs, and required only one scaling and one time delay factor for each subject and speed, which were solved for based on empirical data. Net plantarflexing MTU power was computed by the model and quantitatively compared to inverse dynamics ankle power. Results The EMG-driven model was able to reproduce inverse dynamics ankle power across a range of gait speeds (R2 ≥ 0.97), while also providing MTU-specific power estimates. We found that FDHL dynamics caused ankle power to slightly overestimate net plantarflexor MTU power, but only by ~2–7%. Conclusions During Push-off, FDHL MTU dynamics do not substantially confound the inference of net plantarflexor MTU power from inverse dynamics ankle power. However, other methodological limitations may cause inverse dynamics to overestimate net MTU power; for instance, due to rigid-body foot assumptions. Moving

  15. Stretching Your Energetic Budget: How Tendon Compliance Affects the Metabolic Cost of Running

    PubMed Central

    Uchida, Thomas K.; Hicks, Jennifer L.; Dembia, Christopher L.; Delp, Scott L.

    2016-01-01

    Muscles attach to bones via tendons that stretch and recoil, affecting muscle force generation and metabolic energy consumption. In this study, we investigated the effect of tendon compliance on the metabolic cost of running using a full-body musculoskeletal model with a detailed model of muscle energetics. We performed muscle-driven simulations of running at 2–5 m/s with tendon force–strain curves that produced between 1 and 10% strain when the muscles were developing maximum isometric force. We computed the average metabolic power consumed by each muscle when running at each speed and with each tendon compliance. Average whole-body metabolic power consumption increased as running speed increased, regardless of tendon compliance, and was lowest at each speed when tendon strain reached 2–3% as muscles were developing maximum isometric force. When running at 2 m/s, the soleus muscle consumed less metabolic power at high tendon compliance because the strain of the tendon allowed the muscle fibers to operate nearly isometrically during stance. In contrast, the medial and lateral gastrocnemii consumed less metabolic power at low tendon compliance because less compliant tendons allowed the muscle fibers to operate closer to their optimal lengths during stance. The software and simulations used in this study are freely available at simtk.org and enable examination of muscle energetics with unprecedented detail. PMID:26930416

  16. Musculoskeletal integration at the wrist underlies the modular development of limb tendons

    PubMed Central

    Huang, Alice H.; Riordan, Timothy J.; Pryce, Brian; Weibel, Jennifer L.; Watson, Spencer S.; Long, Fanxin; Lefebvre, Veronique; Harfe, Brian D.; Stadler, H. Scott; Akiyama, Haruhiko; Tufa, Sara F.; Keene, Douglas R.; Schweitzer, Ronen

    2015-01-01

    The long tendons of the limb extend from muscles that reside in the zeugopod (arm/leg) to their skeletal insertions in the autopod (paw). How these connections are established along the length of the limb remains unknown. Here, we show that mouse limb tendons are formed in modular units that combine to form a functional contiguous structure; in muscle-less limbs, tendons develop in the autopod but do not extend into the zeugopod, and in the absence of limb cartilage the zeugopod segments of tendons develop despite the absence of tendons in the autopod. Analyses of cell lineage and proliferation indicate that distinct mechanisms govern the growth of autopod and zeugopod tendon segments. To elucidate the integration of these autopod and zeugopod developmental programs, we re-examined early tendon development. At E12.5, muscles extend across the full length of a very short zeugopod and connect through short anlagen of tendon progenitors at the presumptive wrist to their respective autopod tendon segment, thereby initiating musculoskeletal integration. Zeugopod tendon segments are subsequently generated by proximal elongation of the wrist tendon anlagen, in parallel with skeletal growth, underscoring the dependence of zeugopod tendon development on muscles for tendon anchoring. Moreover, a subset of extensor tendons initially form as fused structures due to initial attachment of their respective wrist tendon anlage to multiple muscles. Subsequent individuation of these tendons depends on muscle activity. These results establish an integrated model for limb tendon development that provides a framework for future analyses of tendon and musculoskeletal phenotypes. PMID:26062940

  17. Musculoskeletal integration at the wrist underlies the modular development of limb tendons.

    PubMed

    Huang, Alice H; Riordan, Timothy J; Pryce, Brian; Weibel, Jennifer L; Watson, Spencer S; Long, Fanxin; Lefebvre, Veronique; Harfe, Brian D; Stadler, H Scott; Akiyama, Haruhiko; Tufa, Sara F; Keene, Douglas R; Schweitzer, Ronen

    2015-07-15

    The long tendons of the limb extend from muscles that reside in the zeugopod (arm/leg) to their skeletal insertions in the autopod (paw). How these connections are established along the length of the limb remains unknown. Here, we show that mouse limb tendons are formed in modular units that combine to form a functional contiguous structure; in muscle-less limbs, tendons develop in the autopod but do not extend into the zeugopod, and in the absence of limb cartilage the zeugopod segments of tendons develop despite the absence of tendons in the autopod. Analyses of cell lineage and proliferation indicate that distinct mechanisms govern the growth of autopod and zeugopod tendon segments. To elucidate the integration of these autopod and zeugopod developmental programs, we re-examined early tendon development. At E12.5, muscles extend across the full length of a very short zeugopod and connect through short anlagen of tendon progenitors at the presumptive wrist to their respective autopod tendon segment, thereby initiating musculoskeletal integration. Zeugopod tendon segments are subsequently generated by proximal elongation of the wrist tendon anlagen, in parallel with skeletal growth, underscoring the dependence of zeugopod tendon development on muscles for tendon anchoring. Moreover, a subset of extensor tendons initially form as fused structures due to initial attachment of their respective wrist tendon anlage to multiple muscles. Subsequent individuation of these tendons depends on muscle activity. These results establish an integrated model for limb tendon development that provides a framework for future analyses of tendon and musculoskeletal phenotypes.

  18. Distribution of proteins within different compartments of tendon varies according to tendon type.

    PubMed

    Thorpe, Chavaunne T; Karunaseelan, Kabelan J; Ng Chieng Hin, Jade; Riley, Graham P; Birch, Helen L; Clegg, Peter D; Screen, Hazel R C

    2016-09-01

    Although 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 energetic cost of locomotion. To maximise energy storage and return, energy-storing tendons need to be more extensible and elastic than tendons with a purely positional function. These properties are conferred in part by a specialisation of a specific compartment of the tendon, the interfascicular matrix, which enables sliding and recoil between adjacent fascicles. However, the composition of the interfascicular matrix is poorly characterised and we therefore tested the hypothesis that the distribution of elastin and proteoglycans differs between energy-storing and positional tendons, and that protein distribution varies between the fascicular matrix and the interfascicular matrix, with localisation of elastin and lubricin to the interfascicular matrix. Protein distribution in the energy-storing equine superficial digital flexor tendon and positional common digital extensor tendon was assessed using histology and immunohistochemistry. The results support the hypothesis, demonstrating enrichment of lubricin in the interfascicular matrix in both tendon types, where it is likely to facilitate interfascicular sliding. Elastin was also localised to the interfascicular matrix, specifically in the energy-storing superficial digital flexor tendon, which may account for the greater elasticity of the interfascicular matrix in this tendon. A differential distribution of proteoglycans was identified between tendon types and regions, which may indicate a distinct role for each of these proteins in tendon. These data provide important advances into fully characterising structure-function relationships within tendon. PMID:27113131

  19. Posterior Tibial Tendon Dysfunction

    MedlinePlus

    ... when the posterior tibial tendon becomes inflamed or torn. As a result, the tendon may not be ... repetitive use. Once the tendon becomes inflamed or torn, the arch will slowly fall (collapse) over time. ...

  20. 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 large cut ...

  1. Achilles tendon rupture - aftercare

    MedlinePlus

    Heel cord tear; Calcaneal tendon rupture ... MRI scan to see what type of Achilles tendon tear you have. An MRI is a type ... partial tear means at least some of the tendon is still OK. A full tear means your ...

  2. Tendon latch

    SciTech Connect

    Watkins, B. J.

    1985-01-01

    A latch connects tendons run from a floating platform to a socket in a foundation on the sea floor. The latch includes a latch body having a plurality of dogs disposed within and urgible outward from the latch body. A piston is releasably disposed within the latch body above the dogs and moves downwardly when released to urge the dogs outwardly from the body into latching engagement with the socket. A trigger mechanism in the latch releases the piston when the latch body lands in the socket and contacts a trigger pin projecting upwardly from the bottom of the socket. A series of wedges are disposed exteriorally on the body and inhibit lateral movement of the body relative to the socket when the tendon is subjected to a cycle bending loads.

  3. Tendon Reattachment to Bone in an Ovine Tendon Defect Model of Retraction Using Allogenic and Xenogenic Demineralised Bone Matrix Incorporated with Mesenchymal Stem Cells

    PubMed Central

    2016-01-01

    Background Tendon-bone healing following rotator cuff repairs is mainly impaired by poor tissue quality. Demineralised bone matrix promotes healing of the tendon-bone interface but its role in the treatment of tendon tears with retraction has not been investigated. We hypothesized that cortical demineralised bone matrix used with minimally manipulated mesenchymal stem cells will result in improved function and restoration of the tendon-bone interface with no difference between xenogenic and allogenic scaffolds. Materials and Methods In an ovine model, the patellar tendon was detached from the tibial tuberosity and a complete distal tendon transverse defect measuring 1 cm was created. Suture anchors were used to reattach the tendon and xenogenic demineralised bone matrix + minimally manipulated mesenchymal stem cells (n = 5), or allogenic demineralised bone matrix + minimally manipulated mesenchymal stem cells (n = 5) were used to bridge the defect. Graft incorporation into the tendon and its effect on regeneration of the enthesis was assessed using histomorphometry. Force plate analysis was used to assess functional recovery. Results Compared to the xenograft, the allograft was associated with significantly higher functional weight bearing at 6 (P = 0.047), 9 (P = 0.028), and 12 weeks (P = 0.009). In the allogenic group this was accompanied by greater remodeling of the demineralised bone matrix into tendon-like tissue in the region of the defect (p = 0.015), and a more direct type of enthesis characterized by significantly more fibrocartilage (p = 0.039). No failures of tendon-bone healing were noted in either group. Conclusion Demineralised bone matrix used with minimally manipulated mesenchymal stem cells promotes healing of the tendon-bone interface in an ovine model of acute tendon retraction, with superior mechanical and histological results associated with use of an allograft. PMID:27606597

  4. [Quadriceps tendon insufficiency and rupture : Treatment options in total knee arthroplasty].

    PubMed

    Thiele, K; von Roth, P; Pfitzner, T; Preininger, B; Perka, C

    2016-05-01

    Quadriceps tendon injuries and insufficiencies in total knee arthroplasty are rare, but are followed by a devastating complication that left untreated leads to a complete loss of function of the knee. This review article summarizes the functional anatomy, risk factors, and the prevalence and diagnosis of quadriceps tendon injuries, in addition to the possible management options for partial and complete ruptures. The treatment options are adapted according to the extent of the loss of function (partial, complete) and the duration of the injury (acute vs chronic). Furthermore, the choice of treatment should take into account the quality and availability of primary tissue, the patient's general health, along with their likely functional requirements. Conservative treatment is often justified in partial ruptures with good results. Complete ruptures require surgical intervention and multiple operative techniques are described. Treatment options for acute ruptures include direct primary repair with autogenous or synthetic tissue augmentation. In the case of chronic insufficiency and a lack of soft-tissue surroundings, reconstruction with the aid of a muscle flap or allograft tissue can be considered. All surgical intervention techniques used so far have been fraught with complications and rarely lead to satisfactory results. A new surgical approach to the reconstruction and augmentation of the extensor mechanism consists of the use of a synthetic mesh. The technique is described here in detail.

  5. Comparison of Clinical Outcome of Autograft and Allograft Reconstruction for Anterior Cruciate Ligament Tears

    PubMed Central

    Jia, Yu-Hua; Sun, Peng-Fei

    2015-01-01

    Background: Hamstring (HS) autograft and bone-patellar tendon-bone allograft are the most common choice for reconstruction of anterior cruciate ligament (ACL). There was a little report about the clinical outcome and difference of arthroscopic ACL reconstruction using allograft and autograft. This study aimed to compare the clinical outcome of autograft and allograft reconstruction for ACL tears. Methods: A total of 106 patients who underwent surgery because of ACL tear were included in this study. The patients were randomly divided into two groups, including 53 patients in each group. The patients in group I underwent standard ACL reconstruction with HS tendon autografts, while others in group II underwent reconstruction with bone-patellar tendon-bone allograft. All the patients were followed up and analyzed; the mean follow-up was 81 months (range: 28–86 months). Clinical outcomes were evaluated using the International Knee Documentation Committee (IKDC), Lysholm scores, physical instability tests, and patient satisfaction questionnaires. The complication rates of both groups were compared. Tibial and femoral tunnel widening were assessed using lateral and anteroposterior radiographs. Results: At the end of follow-up, no significant differences were found between the groups in terms of IKDC, Lysholm scores, physical instability tests, patient satisfaction questionnaires, and incidences of arthrofibrosis. Tibial and femoral tunnel widening was less in the HS tendon autografts. This difference was more significant on the tibial side. Conclusions: In the repair of ACL tears, allograft reconstruction is as effective as the autograft reconstruction, but the allograft can lead to more tunnel widening evidently in the tibial tunnel, particularly. PMID:26612290

  6. Measuring Regional Changes in Damaged Tendon

    NASA Astrophysics Data System (ADS)

    Frisch, Catherine Kayt Vincent

    Mechanical properties of tendon predict tendon health and function, but measuring these properties in vivo is difficult. An ultrasound-based (US) analysis technique called acoustoelastography (AE) uses load-dependent changes in the reflected US signal to estimate tissue stiffness non-invasively. This thesis explores whether AE can provide information about stiffness alteration resulting from tendon tears both ex vivo and in vivo. An ex vivo ovine infraspinatus tendon model suggests that the relative load transmitted by the different tendon layers transmit different fractions of the load and that ultrasound echo intensity change during cyclic loading decreases, becoming less consistent once the tendon is torn. An in vivo human tibialis anterior tendon model using electrically stimulated twitch contractions investigated the feasibility of measuring the effect in vivo. Four of the five subjects showed the expected change and that the muscle contraction times calculated using the average grayscale echo intensity change compared favorably with the times calculated based on the force data. Finally an AE pilot study with patients who had rotator cuff tendon tears found that controlling the applied load and the US view of the system will be crucial to a successful in vivo study.

  7. Mechanical properties of tendons: changes with sterilization and preservation.

    PubMed

    Smith, C W; Young, I S; Kearney, J N

    1996-02-01

    Tendon allografts are commonly used to replace damaged anterior cruciate ligaments (ACL). Some of the sterilization and preservation techniques used by tissue banks with tendon allografts are thought to impair the mechanical properties of graft tissues. The tensile mechanical properties of porcine toe extensor tendons were measured using a dynamic testing machine following either freezing, freeze-drying, freezing then irradiation at 25 kGy (2.5 MRad), freeze-drying then irradiation, or freeze-drying then ethylene oxide gas sterilization. There was a small but significant difference in Young's modulus between the frozen group (0.88 GPa + 0.09 SD) and both the fresh group (0.98 GPa 1 0.12 SD) and the frozen irradiated group (0.97 GPa 1 0.08 SD). No values of Young's modulus were obtained for the freeze-dried irradiated tendons. The ultimate tensile stress (UTS) of the freeze-dried irradiated group (4.7 MPa 1 4.8 SD) was significantly different from both the fresh and the frozen irradiated groups, being reduced by approximately 90 percent. There were no significant changes in UTS or Young's modulus between any of the other groups. If irradiation is to be used to sterilize a tendon replacement for an ACL it must take place after freeze-drying to maintain mechanical properties.

  8. THE ROLE OF MECHANOBIOLOGY IN TENDON HEALING

    PubMed Central

    Killian, Megan L.; Cavinatto, Leonardo; Galatz, Leesa M.; Thomopoulos, Stavros

    2011-01-01

    Mechanical cues affect tendon healing, homeostasis, and development in a variety of settings. Alterations in the mechanical environment are known to result in changes in the expression of extracellular matrix proteins, growth factors, transcription factors, and cytokines that can alter tendon structure and cell viability. Loss of muscle force in utero or in the immediate postnatal period delays tendon and enthesis development. The response of healing tendons to mechanical load varies depending on anatomic location. Flexor tendons require motion to prevent adhesion formation, yet excessive force results in gap formation and subsequent weakening of the repair. Excessive motion in the setting of anterior cruciate ligament reconstruction causes accumulation of macrophages, which are detrimental to tendon graft healing. Complete removal of load is detrimental to rotator cuff healing, yet large forces are also harmful. Controlled loading can enhance healing in most settings; however, a fine balance must be reached between loads that are too low (leading to a catabolic state) and too high (leading to micro-damage). This review will summarize existing knowledge of the mechanobiology of tendon development, homeostasis, and healing. PMID:22244066

  9. Repeated freeze-thaw cycles reduce the survival rate of osteocytes in bone-tendon constructs without affecting the mechanical properties of tendons.

    PubMed

    Suto, Kaori; Urabe, Ken; Naruse, Kouji; Uchida, Kentaro; Matsuura, Terumasa; Mikuni-Takagaki, Yuko; Suto, Mitsutoshi; Nemoto, Noriko; Kamiya, Kentaro; Itoman, Moritoshi

    2012-03-01

    Frozen bone-patellar tendon bone allografts are useful in anterior cruciate ligament reconstruction as the freezing procedure kills tissue cells, thereby reducing immunogenicity of the grafts. However, a small portion of cells in human femoral heads treated by standard bone-bank freezing procedures survive, thus limiting the effectiveness of allografts. Here, we characterized the survival rates and mechanisms of cells isolated from rat bones and tendons that were subjected to freeze-thaw treatments, and evaluated the influence of these treatments on the mechanical properties of tendons. After a single freeze-thaw cycle, most cells isolated from frozen bone appeared morphologically as osteocytes and expressed both osteoblast- and osteocyte-related genes. Transmission electron microscopic observation of frozen cells using freeze-substitution revealed that a small number of osteocytes maintained large nuclei with intact double membranes, indicating that these osteocytes in bone matrix were resistant to ice crystal formation. We found that tendon cells were completely killed by a single freeze-thaw cycle, whereas bone cells exhibited a relatively high survival rate, although survival was significantly reduced after three freeze-thaw cycles. In patella tendons, the ultimate stress, Young's modulus, and strain at failure showed no significant differences between untreated tendons and those subjected to five freeze-thaw cycles. In conclusion, we identified that cells surviving after freeze-thaw treatment of rat bones were predominantly osteocytes. We propose that repeated freeze-thaw cycles could be applied for processing bone-tendon constructs prior to grafting as the treatment did not affect the mechanical property of tendons and drastically reduced surviving osteocytes, thereby potentially decreasing allograft immunogenecity.

  10. A new strategy for the decellularisation of large equine tendons as biocompatible tendon substitutes.

    PubMed

    Bottagisio, M; Pellegata, A F; Boschetti, F; Ferroni, M; Moretti, M; Lovati, A B

    2016-07-08

    Tendon ruptures and/or large losses remain to be a great clinical challenge and often require full replacement of the damaged tissue. The use of auto- and allografts or engineered scaffolds is an established approach to restore severe tendon injuries. However, these grafts are commonly related to scarce biocompatibility, site morbidity, chronic inflammation and poor biomechanical properties. Recently, the decellularisation techniques of allo- or xenografts using specific detergents have been studied and have been found to generate biocompatible substitutes that resemble the native tissue. This study aims to identify a novel decellularisation protocol for large equine tendons that would produce an extracellular matrix scaffold suitable for the regeneration of injured tendons in humans. Specifically, equine tendons were treated either with tri (n-butyl) phosphate alone, or associated to multiple concentrations of peracetic acid (1, 3 and 5 %), which has never before been tested in vitro.Samples were then analysed by histology and with biochemical, biomechanical, and cytotoxicity tests. The best decellularisation protocol, resulting from these examinations, was selected and the chosen scaffold was re-seeded with murine fibroblasts. Resulting grafts were tested for cell viability, histologic analysis, DNA and collagen content. The results identified 1 % tri (n-butyl) phosphate combined with 3 % peracetic acid as the most suitable decellularised matrix in terms of biochemical and biomechanical properties. Moreover, the non-cytotoxic nature of the decellularised matrix allowed for good fibroblast reseeding, thus demonstrating a biocompatible matrix that will be suitable for tendon tissue engineering and hopefully as substitutes in severe tendon damages.

  11. A new strategy for the decellularisation of large equine tendons as biocompatible tendon substitutes.

    PubMed

    Bottagisio, M; Pellegata, A F; Boschetti, F; Ferroni, M; Moretti, M; Lovati, A B

    2016-01-01

    Tendon ruptures and/or large losses remain to be a great clinical challenge and often require full replacement of the damaged tissue. The use of auto- and allografts or engineered scaffolds is an established approach to restore severe tendon injuries. However, these grafts are commonly related to scarce biocompatibility, site morbidity, chronic inflammation and poor biomechanical properties. Recently, the decellularisation techniques of allo- or xenografts using specific detergents have been studied and have been found to generate biocompatible substitutes that resemble the native tissue. This study aims to identify a novel decellularisation protocol for large equine tendons that would produce an extracellular matrix scaffold suitable for the regeneration of injured tendons in humans. Specifically, equine tendons were treated either with tri (n-butyl) phosphate alone, or associated to multiple concentrations of peracetic acid (1, 3 and 5 %), which has never before been tested in vitro.Samples were then analysed by histology and with biochemical, biomechanical, and cytotoxicity tests. The best decellularisation protocol, resulting from these examinations, was selected and the chosen scaffold was re-seeded with murine fibroblasts. Resulting grafts were tested for cell viability, histologic analysis, DNA and collagen content. The results identified 1 % tri (n-butyl) phosphate combined with 3 % peracetic acid as the most suitable decellularised matrix in terms of biochemical and biomechanical properties. Moreover, the non-cytotoxic nature of the decellularised matrix allowed for good fibroblast reseeding, thus demonstrating a biocompatible matrix that will be suitable for tendon tissue engineering and hopefully as substitutes in severe tendon damages. PMID:27386840

  12. Reconstruction of neglected patellar tendon ruptures using the quadriceps graft.

    PubMed

    Gomes, João Luiz Ellera; de Oliveira Alves, Jairo André; Zimmermann, José Mauro

    2014-08-01

    Several techniques using different grafts have been described for reconstruction of the patellar tendon after a neglected rupture. Retraction of the quadriceps tendon may compromise repair integrity due to progressive stretching of the graft. The authors present a surgical technique using the central one-third of the quadriceps tendon. This is supported by the fact that the resistance to traction of this segment of the quadriceps tendon equals that of a double-looped semitendinosus graft and that the harvesting of this specific graft promotes muscle inhibition, thus protecting the reconstruction during the recovery period.

  13. 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

  14. Transverse Compression of Tendons.

    PubMed

    Salisbury, S T Samuel; Buckley, C Paul; Zavatsky, Amy B

    2016-04-01

    A study was made of the deformation of tendons when compressed transverse to the fiber-aligned axis. Bovine digital extensor tendons were compression tested between flat rigid plates. The methods included: in situ image-based measurement of tendon cross-sectional shapes, after preconditioning but immediately prior to testing; multiple constant-load creep/recovery tests applied to each tendon at increasing loads; and measurements of the resulting tendon displacements in both transverse directions. In these tests, friction resisted axial stretch of the tendon during compression, giving approximately plane-strain conditions. This, together with the assumption of a form of anisotropic hyperelastic constitutive model proposed previously for tendon, justified modeling the isochronal response of tendon as that of an isotropic, slightly compressible, neo-Hookean solid. Inverse analysis, using finite-element (FE) simulations of the experiments and 10 s isochronal creep displacement data, gave values for Young's modulus and Poisson's ratio of this solid of 0.31 MPa and 0.49, respectively, for an idealized tendon shape and averaged data for all the tendons and E = 0.14 and 0.10 MPa for two specific tendons using their actual measured geometry. The compression load versus displacement curves, as measured and as simulated, showed varying degrees of stiffening with increasing load. This can be attributed mostly to geometrical changes in tendon cross section under load, varying according to the initial 3D shape of the tendon. PMID:26833218

  15. Transverse Compression of Tendons.

    PubMed

    Salisbury, S T Samuel; Buckley, C Paul; Zavatsky, Amy B

    2016-04-01

    A study was made of the deformation of tendons when compressed transverse to the fiber-aligned axis. Bovine digital extensor tendons were compression tested between flat rigid plates. The methods included: in situ image-based measurement of tendon cross-sectional shapes, after preconditioning but immediately prior to testing; multiple constant-load creep/recovery tests applied to each tendon at increasing loads; and measurements of the resulting tendon displacements in both transverse directions. In these tests, friction resisted axial stretch of the tendon during compression, giving approximately plane-strain conditions. This, together with the assumption of a form of anisotropic hyperelastic constitutive model proposed previously for tendon, justified modeling the isochronal response of tendon as that of an isotropic, slightly compressible, neo-Hookean solid. Inverse analysis, using finite-element (FE) simulations of the experiments and 10 s isochronal creep displacement data, gave values for Young's modulus and Poisson's ratio of this solid of 0.31 MPa and 0.49, respectively, for an idealized tendon shape and averaged data for all the tendons and E = 0.14 and 0.10 MPa for two specific tendons using their actual measured geometry. The compression load versus displacement curves, as measured and as simulated, showed varying degrees of stiffening with increasing load. This can be attributed mostly to geometrical changes in tendon cross section under load, varying according to the initial 3D shape of the tendon.

  16. Multiple variations of the tendons of the anatomical snuffbox

    PubMed Central

    Thwin, San San; Zaini, Fazlin; Than, Myo

    2014-01-01

    INTRODUCTION Multiple tendons of the abductor pollicis longus (APL) in the anatomical snuffbox of the wrist can lead to the development of de Quervain's syndrome, which is caused by stenosing tenosynovitis. A cadaveric study was performed to establish the variations present in the tendons of the anatomical snuffbox in a Malaysian population, in the hope that this knowledge would aid clinical investigation and surgical treatment of de Quervain's tenosynovitis. METHODS Routine dissection of ten upper limbs was performed to determine the variations in the tendons of the anatomical snuffbox of the wrist. RESULTS In all the dissected upper limbs, the APL tendon of the first extensor compartment was found to have several (3–14) tendon slips. The insertion of the APL tendon slips in all upper limbs were at the base of the first metacarpal bone, trapezium and fascia of the opponens pollicis muscle; however, in seven specimens, they were also found to be attached to the fleshy belly of the abductor pollicis brevis muscle. In two specimens, double tendons of the extensor pollicis longus located in the third extensor compartment were inserted into the capsule of the proximal interphalangeal joints before being joined to the extensor expansion. In two other specimens, the first extensor compartment had two osseofibrous tunnels divided by a septum that separated the APL tendon from the extensor pollicis brevis tendon. CONCLUSION Multiple variations were found in the anatomical snuffbox region of the dissected upper limbs. Knowledge of these variations would be useful in interventional radiology and orthopaedic surgery. PMID:24452976

  17. Achilles tendon: US examination

    SciTech Connect

    Fornage, B.D.

    1986-06-01

    Real-time ultrasonography (US) using linear-array probes and a stand-off pad as a ''waterpath'' was performed to evaluate the Achilles tendon in 67 patients (including 24 athletes) believed to have acute or chronic traumatic or inflammatory pathologic conditions. Tendons in 23 patients appeared normal on US scans. The 44 abnormal tendons comprised five complete and four partial ruptures, seven instances of postoperative change, and 28 cases of tendonitis. US depiction of the inner structure of the tendon resulted in the diagnosis of focal abnormalities, including partial ruptures, nodules, and calcifications. Tendonitis was characterized by enlargement and decreased echogenicity of the tendon. The normal US appearance of the Achilles tendon is described.

  18. Pressurized gas filled tendons

    SciTech Connect

    Silcox, W. H.

    1985-06-04

    Pressurized gas filled tubular tendons provide a means for detecting leaks therein. Filling the tendon with a gaseous fluid provides increased buoyancy and reduces the weight supported by the buoyant structure. The use of a corrosion inhibiting gaseous fluid reduces the corrosion of the interior tendon wall.

  19. 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

  20. 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.

  1. Increased Risk of Revision after ACL Reconstruction with Soft Tissue Allograft Compared to Autograft

    PubMed Central

    Maletis, Gregory; Chen, Jason; Inacio, Maria Carolina Secorun; Love, Rebecca; Funahashi, Tadashi Ted

    2016-01-01

    Objectives: The use of allograft tissue for anterior cruciate ligament reconstruction (ACLR) remains controversial. Numerous meta-analysis and systematic reviews of small clinical studies have not found differences between autograft and allograft outcomes but large registry studies have shown an increased risk of revision with allografts. The purpose of this study was to compare the risk of aseptic revision between bone-patellar tendon-bone (BPTB) autografts, hamstring tendon autografts and soft tissue allografts. Methods: A retrospective cohort study of prospectively collected data was conducted using an US ACLR Registry. A cohort of primary unilateral ACLR cases reconstructed with BPTB autografts, hamstring autografts and soft tissue allografts (from any site) was identified. Aseptic revision was the end point of the study. Type of graft and allograft processing methods (non-processed, <1.8Mrads with and without chemical processing (Allowash or AlloTrue methods), >1.8 Mrads irradiation with and without chemical processing, and chemical processing alone (BioCleanse)) were the exposures of interest evaluated. Time from surgery was evaluated as an effect modifier. All analyses were adjusted for age, gender, and race. Kaplan-Meier curves and Cox proportional hazard models were employed. Hazard ratios (HR), 95% confidence intervals (CI) are provided. Results: The cohort had 14015 cases, 8924 (63.7%) were male, 6397 (45.6%) were White, 4557 (32.5%) cases used BPTB autograft, 3751 (26.8%) cases used soft tissue allograft and 5707 (40.7%) cases used hamstring autograft. The median age was 34.6 years-old (IQR 24.1-43.2) for allograft cases and 24.3 years-old (IQR 17.7-33.8) for hamstring autograft cases, and 22.0 years-old (IQR 17.6-30.0) for BPTB autograft cases. Compared to hamstring tendon autografts, an increased risk of revision was found in allografts processed with >1.8Mrads without chemical processing after 2.5 years (HR: 3.88 95%CI 1.48-10.12), and >1.8Mrads with

  2. Re-revision of a patellar tendon rupture in a young professional martial arts athlete.

    PubMed

    Vadalà, A; Iorio, R; Bonifazi, A M; Bolle, G; Ferretti, A

    2012-09-01

    A 27-year-old professional martial arts athlete experienced recurrent right knee patellar tendon rupture on three occasions. He underwent two operations for complete patellar tendon rupture: an end-to-end tenorrhaphy the first time, and revision with a bone-patellar-tendon (BPT) allograft. After the third episode, he was referred to our department, where we performed a surgical reconstruction with the use of hamstring pro-patellar tendon, in a figure-of-eight configuration, followed by a careful rehabilitation protocol. Clinical and radiological follow-ups were realized at 1, 3, and 6 months and 1 and 2 years postop, with an accurate physical examination, the use of recognized international outcome scores, and radiograph and MRI studies. As far as we know, this is the first paper to report a re-revision of a patellar tendon rupture.

  3. Elastographic characteristics of the metacarpal tendons in horses without clinical evidence of tendon injury.

    PubMed

    Lustgarten, Meghann; Redding, W Rich; Labens, Raphael; Morgan, Michel; Davis, Weston; Seiler, Gabriela S

    2014-01-01

    Tendon and ligament injuries are common causes of impaired performance in equine athletes. Gray-scale ultrasonography is the current standard method for diagnosing and monitoring these injuries, however this modality only provides morphologic information. Elastography is an ultrasound technique that allows detection and measurement of tissue strain, and may provide valuable mechanical information about equine tendon and ligament injuries. The purpose of this study was to determine the feasibility, reproducibility, and repeatability of elastography; and to describe elastographic characteristics of metacarpal tendons in sound horses. Nineteen legs for 17 clinically sound horses without evidence of musculoskeletal pathology were included. Elastographic images of the superficial and deep digital flexor tendons and the branches of the suspensory ligament (tendon of the interosseous muscle) were described quantitatively and qualitatively. There was no statistically significant difference between operators (P = 0.86) nor within operators (P = 0.93). For qualitative assessments, reproducibility (0.46) was moderate and repeatability (0.78) was good. Similar to human Achilles tendons, equine tendons were classified as predominantly hard using elastography. There was no statistically significant difference in stiffness of the flexor tendons (P = 0.96). No significant difference in stiffness was found with altered leg position during standing (P = 0.84) and while nonweight bearing (P = 0.61). The flexor tendons were softer when imaged in longitudinal versus transverse planes (P < 0.01) however, the suspensory branches were not (P = 0.67). Findings supported future clinical application of elastography as a noninvasive "stall-side" imaging modality for evaluation of the tendons and ligaments of the distal forelimb in horses.

  4. Radial Nerve Tendon Transfers.

    PubMed

    Cheah, Andre Eu-Jin; Etcheson, Jennifer; Yao, Jeffrey

    2016-08-01

    Radial nerve palsy typically occurs as a result of trauma or iatrogenic injury and leads to the loss of wrist extension, finger extension, thumb extension, and a reduction in grip strength. In the absence of nerve recovery, reconstruction of motor function involves tendon transfer surgery. The most common donor tendons include the pronator teres, wrist flexors, and finger flexors. The type of tendon transfer is classified based on the donor for the extensor digitorum communis. Good outcomes have been reported for most methods of radial nerve tendon transfers as is typical for positional tendon transfers not requiring significant power. PMID:27387076

  5. Fibrillins in Tendon

    PubMed Central

    Giusti, Betti; Pepe, Guglielmina

    2016-01-01

    Tendons among connective tissue, mainly collagen, contain also elastic fibers (EF) made of fibrillin 1, fibrillin 2 and elastin that are broadly distributed in tendons and represent 1–2% of the dried mass of the tendon. Only in the last years, studies on structure and function of EF in tendons have been performed. Aim of this review is to revise data on the organization of EF in tendons, in particular fibrillin structure and function, and on the clinical manifestations associated to alterations of EF in tendons. Indeed, microfibrils may contribute to tendon mechanics; therefore, their alterations may cause joint hypermobility and contractures which have been found to be clinical features in patients with Marfan syndrome (MFS) and Beals syndrome. The two diseases are caused by mutations in genes FBN1 and FBN2 encoding fibrillin 1 and fibrillin 2, respectively. PMID:27812333

  6. Gastrocnemius myotendinous flap for patellar or quadriceps tendon repair, or both.

    PubMed

    Rhomberg, M; Schwabegger, A H; Ninkovic, M; Bauer, T; Ninkovic, M

    2000-08-01

    The authors' experience with simultaneous reconstruction of the quadriceps femoris or patellar tendon or both and soft tissue defect using a musculotendinous unit of the gastrocnemius muscle is presented. Five patients with a partial or complete defect of the quadriceps or patellar tendon or both and additional large soft tissue defects underwent reconstruction applying this technique as a one-stage surgical procedure in different variations. In cases with a partial defect of the tendon or loss of tendon thickness, the thick aponeurosis from the deeper aspect of the gastrocnemius was dissected and transferred as a pedicled tendon flap to reconstruct the tendon defect. In cases with a complete defect of the tendon, the superficial layer of the Achilles tendon together with the deep aponeurotic layer of the gastrocnemius muscle served to reconstruct the tendon. In both procedures the gastrocnemius muscle belly provided soft tissue coverage and was covered with a split thickness skin graft. One patient had a marginal deep necrosis develop that had to be covered with the other gastrocnemius muscle in a second operation. One patient with chronic polyarthritis and infection of his knee prosthesis declined additional reconstruction surgery and had the leg amputated. The average followup was 3.5 years. All patients achieved good results in active extension of the knee with an extension deficit of only 5 degrees to 15 degrees. The range of flexion was at least 90 degrees. The surgical technique described in this report provides functional tendon reconstruction and adequate soft tissue repair simultaneously.

  7. Engineering Tendon: Scaffolds, Bioreactors, and Models of Regeneration.

    PubMed

    Youngstrom, Daniel W; Barrett, Jennifer G

    2016-01-01

    Tendons bridge muscle and bone, translating forces to the skeleton and increasing the safety and efficiency of locomotion. When tendons fail or degenerate, there are no effective pharmacological interventions. The lack of available options to treat damaged tendons has created a need to better understand and improve the repair process, particularly when suitable autologous donor tissue is unavailable for transplantation. Cells within tendon dynamically react to loading conditions and undergo phenotypic changes in response to mechanobiological stimuli. Tenocytes respond to ultrastructural topography and mechanical deformation via a complex set of behaviors involving force-sensitive membrane receptor activity, changes in cytoskeletal contractility, and transcriptional regulation. Effective ex vivo model systems are needed to emulate the native environment of a tissue and to translate cell-matrix forces with high fidelity. While early bioreactor designs have greatly expanded our knowledge of mechanotransduction, traditional scaffolds do not fully model the topography, composition, and mechanical properties of native tendon. Decellularized tendon is an ideal scaffold for cultivating replacement tissue and modeling tendon regeneration. Decellularized tendon scaffolds (DTS) possess high clinical relevance, faithfully translate forces to the cellular scale, and have bulk material properties that match natural tissue. This review summarizes progress in tendon tissue engineering, with a focus on DTS and bioreactor systems. PMID:26839559

  8. Engineering Tendon: Scaffolds, Bioreactors, and Models of Regeneration

    PubMed Central

    Youngstrom, Daniel W.; Barrett, Jennifer G.

    2016-01-01

    Tendons bridge muscle and bone, translating forces to the skeleton and increasing the safety and efficiency of locomotion. When tendons fail or degenerate, there are no effective pharmacological interventions. The lack of available options to treat damaged tendons has created a need to better understand and improve the repair process, particularly when suitable autologous donor tissue is unavailable for transplantation. Cells within tendon dynamically react to loading conditions and undergo phenotypic changes in response to mechanobiological stimuli. Tenocytes respond to ultrastructural topography and mechanical deformation via a complex set of behaviors involving force-sensitive membrane receptor activity, changes in cytoskeletal contractility, and transcriptional regulation. Effective ex vivo model systems are needed to emulate the native environment of a tissue and to translate cell-matrix forces with high fidelity. While early bioreactor designs have greatly expanded our knowledge of mechanotransduction, traditional scaffolds do not fully model the topography, composition, and mechanical properties of native tendon. Decellularized tendon is an ideal scaffold for cultivating replacement tissue and modeling tendon regeneration. Decellularized tendon scaffolds (DTS) possess high clinical relevance, faithfully translate forces to the cellular scale, and have bulk material properties that match natural tissue. This review summarizes progress in tendon tissue engineering, with a focus on DTS and bioreactor systems. PMID:26839559

  9. Engineering Tendon: Scaffolds, Bioreactors, and Models of Regeneration.

    PubMed

    Youngstrom, Daniel W; Barrett, Jennifer G

    2016-01-01

    Tendons bridge muscle and bone, translating forces to the skeleton and increasing the safety and efficiency of locomotion. When tendons fail or degenerate, there are no effective pharmacological interventions. The lack of available options to treat damaged tendons has created a need to better understand and improve the repair process, particularly when suitable autologous donor tissue is unavailable for transplantation. Cells within tendon dynamically react to loading conditions and undergo phenotypic changes in response to mechanobiological stimuli. Tenocytes respond to ultrastructural topography and mechanical deformation via a complex set of behaviors involving force-sensitive membrane receptor activity, changes in cytoskeletal contractility, and transcriptional regulation. Effective ex vivo model systems are needed to emulate the native environment of a tissue and to translate cell-matrix forces with high fidelity. While early bioreactor designs have greatly expanded our knowledge of mechanotransduction, traditional scaffolds do not fully model the topography, composition, and mechanical properties of native tendon. Decellularized tendon is an ideal scaffold for cultivating replacement tissue and modeling tendon regeneration. Decellularized tendon scaffolds (DTS) possess high clinical relevance, faithfully translate forces to the cellular scale, and have bulk material properties that match natural tissue. This review summarizes progress in tendon tissue engineering, with a focus on DTS and bioreactor systems.

  10. Anterior cruciate ligament reconstruction with BPTB autograft, irradiated versus non-irradiated allograft: a prospective randomized clinical study.

    PubMed

    Sun, Kang; Tian, Shaoqi; Zhang, Jihua; Xia, Changsuo; Zhang, Cailong; Yu, Tengbo

    2009-05-01

    The effect of using gamma irradiation to sterilize bone-patellar tendon-bone (BPTB) allograft on the clinical outcomes of anterior cruciate ligament (ACL) reconstruction with irradiated allograft remains controversial. Our study was aimed to analyze the clinical outcomes of arthroscopic ACL reconstruction with irradiated BPTB allograft compared with non-irradiated allograft and autograft. All BPTB allografts were obtained from a single tissue bank and the irradiated allografts were sterilized with 2.5 Mrad of irradiation prior to distribution. A total of 102 patients undergoing arthroscopic ACL reconstruction were prospectively randomized consecutively into three groups. The same surgical technique was used in all operations done by the same senior surgeon. Before surgery and at the average of 31 months follow-up (range 24-47 months) patients were evaluated by the same observer according to objective and subjective clinical evaluations. Of these patients, 99 (autograft 33, non-irradiated allograft 34, irradiated allograft 32) were available for full evaluation. When compared the irradiated allograft group to non-irradiated allograft group or autograft group at 31 months follow-up by the Lachman test, ADT, pivot shift test and KT-2000 arthrometer testing, statistically significant differences were found. Most importantly, 87.8% of patients in the Auto group, 85.3% in the Non-Ir-Auto group and just only 31.3% in the Ir-Allo group had a side-to-side difference of less than 3 mm according to KT-2000. The failure rate of the ACL reconstruction with irradiated allograft (34.4%) was higher than that with autograft (6.1%) and non-irradiated allograft (8.8%). The anterior and rotational stability decreased significantly in the irradiated allograft group. According to the overall IKDC, functional, subjective evaluations and activity level testing, no statistically significant differences were found between the three groups. However, there was a trend that the functional and

  11. Active tendon implants in flexor tendon reconstruction.

    PubMed

    Hunter, J M; Singer, D I; Jaeger, S H; Mackin, E J

    1988-11-01

    Forty-five active flexor tendon implants were evaluated after placement in scarred tendon beds of digits II through V. The implant is constructed of silicone rubber with a Dacron core, terminating in a loop proximally and a metal plate distally. Modification of the implant during the period of study has improved its reliability and longevity. The improvement in total active motion (TAM) averaged 72 degrees during implant functioning (stage I) in a group of digits that before operation were classified as 78% Boyes grade 5 (salvage). Complication rate during stage I was 11% (5 out of 45). Of the 27 digits evaluated after implant replacement by tendon autograft (stage II), there was an overall improvement in 62 degrees total active motion with 70% of digits being Boyes grade 5. Many of the complications were believed to be avoidable with experience. This study demonstrates the feasibility of an active tendon implant and the possibility of a permanent prosthesis. PMID:2976074

  12. Atraumatic quadriceps tendon tear associated with calcific tendonitis.

    PubMed

    Abram, Simon G F; Sharma, Akash D; Arvind, Chinnakonda

    2012-11-27

    Calcific tendonitis of the quadriceps tendon is an uncommon condition. We present the first case of a quadriceps tendon tear associated with calcific tendonitis. In this case, the patient presented with symptoms mimicking a rupture of the quadriceps tendon. This case illustrates that although calcific tendonitis of the quadriceps is a rare condition it is not benign and should be considered when investigating acute symptoms associated with the extensor mechanism of the knee.

  13. 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

  14. 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.

  15. Principles of Tendon Transfer.

    PubMed

    Wilbur, Danielle; Hammert, Warren C

    2016-08-01

    Tendon transfers provide a substitute, either temporary or permanent, when function is lost due to neurologic injury in stroke, cerebral palsy or central nervous system lesions, peripheral nerve injuries, or injuries to the musculotendinous unit itself. This article reviews the basic principles of tendon transfer, which are important when planning surgery and essential for an optimal outcome. In addition, concepts for coapting the tendons during surgery and general principles to be followed during the rehabilitation process are discussed. PMID:27387072

  16. Riser and tendon management system

    SciTech Connect

    Devlin, P.V.

    1992-02-18

    This patent describes a riser and tendon management system. It comprises means to set nominal conditions for the risers and tendons; means to measure actual riser and tendon conditions; means to compare the actual and nominal conditions of the risers and tendons; and means responsive to a differential between the actual and nominal riser and tendon conditions, which difference exceeds specified limits, and recommending corrective action to bring the risers and tendons back to within nominal conditions.

  17. Tendon and ligament imaging

    PubMed Central

    Hodgson, R J; O'Connor, P J; Grainger, A J

    2012-01-01

    MRI and ultrasound are now widely used for the assessment of tendon and ligament abnormalities. Healthy tendons and ligaments contain high levels of collagen with a structured orientation, which gives rise to their characteristic normal imaging appearances as well as causing particular imaging artefacts. Changes to ligaments and tendons as a result of disease and injury can be demonstrated using both ultrasound and MRI. These have been validated against surgical and histological findings. Novel imaging techniques are being developed that may improve the ability of MRI and ultrasound to assess tendon and ligament disease. PMID:22553301

  18. Tendon Homeostasis in Hypercholesterolemia.

    PubMed

    Soslowsky, Louis J; Fryhofer, George W

    2016-01-01

    Hypercholesterolemia is a serious health problem that is associated not only with heart disease, but also tendon pathology. In high cholesterol environments (e.g. familial hyperlipidemia), lipids accumulate within the tendon extracellular matrix and form deposits called xanthomas. Lipid-related changes are known to affect several tendon mechanical properties, including stiffness and modulus, in uninjured and injured tendons, alike. Mechanisms to explain these cholesterol-related changes are multiple, including alterations in tenocyte gene and protein expression, matrix turnover, tissue vascularity, and cytokine production. Clinically, rotator cuff tear and Achilles tendon rupture are clearly associated with metabolic derangements, and elevated total cholesterol is often among the specific metabolic parameters implicated. Treatment of hypercholesterolemia using statin medications has also been shown to affect tendon properties, resulting in normalization of tendon thickness and improved tendon healing. Despite current work, the pathophysiology of lipid-related tendon pathology remains incompletely understood, and additional hypothesis-generating studies, including those incorporating whole-genome and whole-transcriptome technologies, will help to point the field in new directions. PMID:27535257

  19. Inflammation in Tendon Disorders.

    PubMed

    Speed, Cathy

    2016-01-01

    The role of inflammation in tendon disorders has long been a subject of considerable debate. Developments in our understanding of the basic science of inflammation have provided further insight into its potential role in specific forms of tendon disease, and the circumstances that may potentiate this. Such circumstances include excessive mechanical stresses on tendon and the presence of systemic inflammation associated with chronic diseases. In this chapter a brief review of the basic science of inflammation is provided and the influence that it may play on tendons is discussed. PMID:27535263

  20. Specialisation of extracellular matrix for function in tendons and ligaments

    PubMed Central

    Birch, Helen L.; Thorpe, Chavaunne T.; Rumian, Adam P.

    2013-01-01

    Summary Tendons and ligaments are similar structures in terms of their composition, organisation and mechanical properties. The distinction between them stems from their anatomical location; tendons form a link between muscle and bone while ligaments link bones to bones. A range of overlapping functions can be assigned to tendon and ligaments and each structure has specific mechanical properties which appear to be suited for particular in vivo function. The extracellular matrix in tendon and ligament varies in accordance with function, providing appropriate mechanical properties. The most useful framework in which to consider extracellular matrix differences therefore is that of function rather than anatomical location. In this review we discuss what is known about the relationship between functional requirements, structural properties from molecular to gross level, cellular gene expression and matrix turnover. The relevance of this information is considered by reviewing clinical aspects of tendon and ligament repair and reconstructive procedures. PMID:23885341

  1. Interference screw fixation and short harvest using flexor digitorum longus (FDL) transfer for posterior tibial tendon dysfunction: a technique.

    PubMed

    Bussewitz, Bradly W; Hyer, Christopher F

    2010-01-01

    Posterior tibial tendon dysfunction is a common clinical entity treated by foot and ankle specialists, and numerous surgical treatments are available to the modern foot and ankle surgeon. Fixation methods are constantly evolving as new products are developed and new uses for existing products are attempted. Interference screw fixation is the gold standard fixation for tendon autograft and allograft in orthopedic sports medicine. The technique that we describe in this article uses a less extensive harvest of the flexor digitorum longus tendon and a sound fixation method using an interference screw positioned in the tarsal navicular. PMID:20797592

  2. 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.

  3. Nonlinear optical imaging characteristics in rat tail tendon

    NASA Astrophysics Data System (ADS)

    Liu, N. R.; Zhang, X. Z.; Qiu, Y. S.; Chen, R.

    2013-04-01

    The aim of this study was to examine the characteristics of skeletal muscle fibers in tail tendons, explore the content of intrinsic components at different depths and ascertain the optimum excitation wavelength, which will help to establish a relationship between diagnosis and therapy and the tendon injury. A multiphoton microscopic imaging system was used to achieve the images and spectra via an imaging mode and a Lambda mode, respectively. This work demonstrates that the skeletal muscle fibers of the tail tendon are in good order. Second harmonic generation (SHG) and two-photon excited fluorescence (TPEF) signals originating from certain intrinsic components are varied with depth, and the SHG/TPEF intensity ratios are varied at different excitation wavelengths. Below 800 nm is the optimum for cell TPEF, while above 800 nm is the optimum for SHG. With the development of imaging techniques, a nonlinear optical imaging system will be helpful to represent the functional behaviors of tissue related to tendon injury.

  4. Effects of gamma irradiation and repetitive freeze-thaw cycles on the biomechanical properties of human flexor digitorum superficialis tendons.

    PubMed

    Ren, Dejie; Sun, Kang; Tian, Shaoqi; Yang, Xu; Zhang, Cailong; Wang, Wenhao; Huang, Hongjie; Zhang, Jihua; Deng, Yujie

    2012-01-10

    An increasing number of tissue banks have begun to focus on gamma irradiation and freeze-thaw in the reconstruction of anterior cruciate ligaments using allografts. The purpose of this study was to evaluate the biomechanical properties of human tendons after exposure to gamma radiation and repeated freeze-thaw cycles and to compare them with fresh specimens. Forty flexor digitorum superficialis tendons were surgically procured from five fresh cadavers and divided into four groups: fresh tendon, gamma irradiation, freeze-thaw and gamma irradiation+freeze-thaw. The dose of gamma irradiation was 25 kGy. Each freeze-thaw cycle consisted of freezing at -80 °C for 7 day and thawing at 25 °C for 6 h. These tendons underwent 4 freeze-thaw cycles. Biomechanical properties were analyzed during load-to-failure testing. The fresh tendons were found to be significantly different in ultimate load, stiffness and ultimate stress relative to the other three groups. The tendons of the gamma+freeze-thaw group showed a significant decrease in ultimate load, ultimate stress and stiffness compared with the other three groups. Gamma irradiation and repeated freezing-thawing (4 cycles) can change the biomechanical properties. However, no significant difference was found between these two processes on the effect of biomechanical properties. It is recommended that gamma irradiation (25 kGy) and repetitive freeze-thaw cycles (4 cycles) should not be adopted in the processing of the allograft tendons.

  5. 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

  6. Tendon Transfers for Tetraplegia.

    PubMed

    Bednar, Michael S

    2016-08-01

    It is estimated that 65% to 75% of patients with cervical spinal cord injuries could benefit from upper extremity tendon transfer surgery. The goals of surgery are to restore elbow extension, as well as hand pinch, grasp, and release. Patients who have defined goals, actively participate in therapy, and understand expected outcomes, appear to have the highest satisfaction following tendon transfer procedures. PMID:27387082

  7. 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

  8. Inducement of tissue regeneration of harvested hamstring tendons in a rabbit model

    PubMed Central

    Soejima, T.; Murakami, H.; Noguchi, K.; Shiba, N.; Nagata, K.

    2016-01-01

    Objectives The objective of this study was to determine if the use of fascia lata as a tendon regeneration guide (placed into the tendon canal following harvesting the semitendinosus tendon) would improve the incidence of tissue regeneration and prevent fatty degeneration of the semitendinosus muscle. Materials and Methods Bilateral semitendinosus tendons were harvested from rabbits using a tendon stripper. On the inducing graft (IG) side, the tendon canal and semitendinosus tibial attachment site were connected by the fascia lata, which was harvested at the same width as the semitendinosus tendon. On the control side, no special procedures were performed. Two groups of six rabbits were killed at post-operative weeks 4 and 8, respectively. In addition, three healthy rabbits were killed to obtain normal tissue. We evaluated the incidence of tendon tissue regeneration, cross-sectional area of the regenerated tendon tissue and proportion of fatty tissue in the semitendinosus muscle. Results At post-operative week 8, the distal end of the regenerated tissue reached the vicinity of the tibial insertion on the control side in two of six specimens. On the IG side, the regenerated tissue maintained continuity with the tibial insertion in all specimens. The cross-sectional area of the IG side was significantly greater than that of the control side. The proportion of fatty tissue in the semitendinosus muscle on the IG side was comparable with that of the control side, but was significantly greater than that of the normal muscle. Conclusions Tendon tissue regenerated with the fascia lata graft was thicker than naturally occurring regenerated tissue. However, the proportion of fatty tissue in the semitendinosus muscle was greater than that of normal muscle. Cite this article: K. Tabuchi, T. Soejima, H. Murakami, K. Noguchi, N. Shiba, K. Nagata. Inducement of tissue regeneration of harvested hamstring tendons in a rabbit model. Bone Joint Res 2016;5:247–252. DOI: 10

  9. The tibialis posterior tendon.

    PubMed

    Lhoste-Trouilloud, A

    2012-02-01

    The tibialis posterior tendon is the largest and anteriormost tendon in the medial ankle. It produces plantar flexion and supination of the ankle and stabilizes the plantar vault. Sonographic assessment of this tendon is done with high-frequency, linear-array transducers; an optimal examination requires transverse retromalleolar, longitudinal retromalleolar, and distal longitudinal scans, as well as dynamic studies. Disorders of the posterior tibial tendon include chronic tendinopathy with progressive rupture, tenosynovitis, acute rupture, dislocation and instability, enthesopathies. The most common lesion is a progressive "chewing gum" lesion that develops in a setting of chronic tendinopathy; it is usually seen in overweight women over 50 years of age with valgus flat feet. Medial ankle pain must also be carefully investigated, and the presence of instability assessed with dynamic maneuvers (forced inversion, or dorsiflexion) of the foot. Sonography plays an important role in the investigation of disorders involving the posterior tibial tendon.

  10. Is there significant variation in the material properties of four different allografts implanted for ACL reconstruction.

    PubMed

    Penn, David; Willet, Thomas L; Glazebrook, Mark; Snow, Martyn; Stanish, William D

    2009-03-01

    The aims of our study were to: (1) determine if there are differences in the material properties of tendon obtained from implanted tibialis anterior, achilles, bone-patella- bone and tibialis posterior allografts; (2) determine the variability in material properties between the implanted specimens. A total of 60 specimens were collected from fresh frozen allografts implanted at ACL reconstruction. Specimens collected included 15 tibialis anterior, 15 tibialis posterior, 15 achilles and 15 bone-patella-bone tendons. Each specimen was mounted in a custom made cryogrip. The mounted specimens were loaded onto a MTS Testline servo-hydraulic testing machine in a uni-axial tensile test configuration. Specimens were subjected to a strain rate of 5% per second until the ultimate tensile stress (UTS), failure strain and high strain modulus was calculated for each specimen after being normalized for specimen dimensions. Individual material properties were tested using one way analysis of variance (ANOVA) and post hoc Tukey's B test with a P value of <0.05 considered significant. Homogeneity of variance was assessed using the Levene's test. As a result, no significant difference was found between all four grafts with regards to UTS, failure strain or high strain linear modulus. The UTS was plotted against the modulus demonstrating a linear relationship which is typical of soft tissues. Significant variability in the results were observed. In conclusion, there was no significant statistical difference between the material properties of the four tendon allografts tested. But significant variability in results was observed within groups and between groups, which may provide one explanation for the range of results in allograft ACL reconstruction reported in the literature.

  11. Is there significant variation in the material properties of four different allografts implanted for ACL reconstruction.

    PubMed

    Penn, David; Willet, Thomas L; Glazebrook, Mark; Snow, Martyn; Stanish, William D

    2009-03-01

    The aims of our study were to: (1) determine if there are differences in the material properties of tendon obtained from implanted tibialis anterior, achilles, bone-patella- bone and tibialis posterior allografts; (2) determine the variability in material properties between the implanted specimens. A total of 60 specimens were collected from fresh frozen allografts implanted at ACL reconstruction. Specimens collected included 15 tibialis anterior, 15 tibialis posterior, 15 achilles and 15 bone-patella-bone tendons. Each specimen was mounted in a custom made cryogrip. The mounted specimens were loaded onto a MTS Testline servo-hydraulic testing machine in a uni-axial tensile test configuration. Specimens were subjected to a strain rate of 5% per second until the ultimate tensile stress (UTS), failure strain and high strain modulus was calculated for each specimen after being normalized for specimen dimensions. Individual material properties were tested using one way analysis of variance (ANOVA) and post hoc Tukey's B test with a P value of <0.05 considered significant. Homogeneity of variance was assessed using the Levene's test. As a result, no significant difference was found between all four grafts with regards to UTS, failure strain or high strain linear modulus. The UTS was plotted against the modulus demonstrating a linear relationship which is typical of soft tissues. Significant variability in the results were observed. In conclusion, there was no significant statistical difference between the material properties of the four tendon allografts tested. But significant variability in results was observed within groups and between groups, which may provide one explanation for the range of results in allograft ACL reconstruction reported in the literature. PMID:19039574

  12. Drug-Induced Tendon Disorders.

    PubMed

    Knobloch, Karsten

    2016-01-01

    Drug-induced tendon disorders are an often underestimated risk factor. The range from detrimental effects on the tendon include tendinopathy as well as potentially tendon rupture. As for today, four main drug classes have been reported to be associated with potentially deteriorated tendon properties: 1. Corticosteroids, 2. Chinolon antibiotics, 3. Aromatase inhbitors, 4. Statins as HMG-CoA-reductase inhibitors. Most often, the Achilles tendon is affected in terms of tendinopathy and/or subsequent tendon rupture. However, nearly every tendon of the entire body might be affected in a detrimental way by one or a combination of the aformentioned agents. PMID:27535265

  13. Surgical Treatment of Neglected Traumatic Quadriceps Tendon Rupture with Knee Ankylosis

    PubMed Central

    Lee, Seung-Hun; Seon, Jong-Keun; Woo, Seong-Hwan

    2016-01-01

    Quadriceps tendon rupture is an uncommon injury. This disabling condition is the result of direct or indirect trauma. It requires surgical repair to avoid poor outcomes in cases of neglected or chronic rupture. In most acute cases, simple tendon suture or reinsertion is suitable for an extensor mechanism reconstruction of the knee joint. However, chronic lesions often require a tendon graft or flap reconstruction. We report a case of a 15-year-old male who was diagnosed with a chronic quadriceps rupture with a patellar superior pole fracture. We performed quadriceps reconstruction using tibialis anterior allograft tendon and additional screw fixation to reconstruct the extensor mechanism and recover knee joint range of motion to prevent a high-level functional restriction. The treatment was difficult and limited due to neglect for 9-months that led to ankylosis accompanied with nonunion of tibial fracture. Our surgical treatment using allograft tendon resulted in a very good outcome after 30 months of follow-up. PMID:27274474

  14. Bilateral Congenital Agenesis of the Long Head of the Biceps Tendon: The Beginning

    PubMed Central

    Rego Costa, Francisco; Esteves, Cátia; Melão, Lina

    2016-01-01

    The biceps brachii muscle is prone to variants but absence of the long head of the biceps (LHB) tendon is an exceptionally rare anomaly. This report concerns the fourth case of bilateral congenital absence of the LHB tendon and presents the ultrasonography (US) and magnetic resonance (MR) findings. Our case has the peculiarity of being the first in which bilateral LHB tendon agenesis is not associated with rotator cuff or labral tears. PMID:26904345

  15. The role of hind limb tendons in gibbon locomotion: springs or strings?

    PubMed

    Vereecke, Evie E; Channon, Anthony J

    2013-11-01

    Tendon properties have an important effect on the mechanical behaviour of muscles, with compliant tendons allowing near-isometric muscle contraction and facilitating elastic energy storage and recoil. Stiff tendons, in contrast, facilitate rapid force transfer and precise positional control. In humans, the long Achilles tendon contributes to the mechanical efficiency of running via elastic energy storage and recovery, and its presence has been linked to the evolution of habitual bipedalism. Gibbons also possess relatively long hind limb tendons; however, their role is as yet unknown. Based on their large dimensions, and inferring from the situation in humans, we hypothesize that the tendons in the gibbon hind limb will facilitate elastic energy storage and recoil during hind-limb-powered locomotion. To investigate this, we determined the material properties of the gibbon Achilles and patellar tendon in vitro and linked this with available kinematic and kinetic data to evaluate their role in leaping and bipedalism. Tensile tests were conducted on tendon samples using a material testing machine and the load-displacement data were used to calculate stiffness, Young's modulus and hysteresis. In addition, the average stress-in-life and energy absorption capacity of both tendons were estimated. We found a functional difference between the gibbon Achilles and patellar tendon, with the Achilles tendon being more suitable for elastic energy storage and release. The patellar tendon, in contrast, has a relatively high hysteresis, making it less suitable to act as elastic spring. This suggests that the gibbon Achilles tendon might fulfil a similar function as in humans, contributing to reducing the locomotor cost of bipedalism by acting as elastic spring, while the high stiffness of the patellar tendon might favour fast force transfer upon recoil and, possibly, enhance leaping performance.

  16. How Obesity Affects Tendons?

    PubMed

    Abate, Michele; Salini, Vincenzo; Andia, Isabel

    2016-01-01

    Several epidemiological and clinical observations have definitely demonstrated that obesity has harmful effects on tendons. The pathogenesis of tendon damage is multi-factorial. In addition to overload, attributable to the increased body weight, which significantly affects load-bearing tendons, systemic factors play a relevant role. Several bioactive peptides (chemerin, leptin, adiponectin and others) are released by adipocytes, and influence tendon structure by means of negative activities on mesenchymal cells. The ensuing systemic state of chronic, sub-clinic, low-grade inflammation can damage tendon structure. Metabolic disorders (diabetes, impaired glucose tolerance, and dislipidemia), frequently associated with visceral adiposity, are concurrent pathogenetic factors. Indeed, high glucose levels increase the formation of Advanced Glycation End-products, which in turn form stable covalent cross-links within collagen fibers, modifying their structure and functionality.Sport activities, so useful for preventing important cardiovascular complications, may be detrimental for tendons if they are submitted to intense acute or chronic overload. Therefore, two caution rules are mandatory: first, to engage in personalized soft training program, and secondly to follow regular check-up for tendon pathology.

  17. How Obesity Affects Tendons?

    PubMed

    Abate, Michele; Salini, Vincenzo; Andia, Isabel

    2016-01-01

    Several epidemiological and clinical observations have definitely demonstrated that obesity has harmful effects on tendons. The pathogenesis of tendon damage is multi-factorial. In addition to overload, attributable to the increased body weight, which significantly affects load-bearing tendons, systemic factors play a relevant role. Several bioactive peptides (chemerin, leptin, adiponectin and others) are released by adipocytes, and influence tendon structure by means of negative activities on mesenchymal cells. The ensuing systemic state of chronic, sub-clinic, low-grade inflammation can damage tendon structure. Metabolic disorders (diabetes, impaired glucose tolerance, and dislipidemia), frequently associated with visceral adiposity, are concurrent pathogenetic factors. Indeed, high glucose levels increase the formation of Advanced Glycation End-products, which in turn form stable covalent cross-links within collagen fibers, modifying their structure and functionality.Sport activities, so useful for preventing important cardiovascular complications, may be detrimental for tendons if they are submitted to intense acute or chronic overload. Therefore, two caution rules are mandatory: first, to engage in personalized soft training program, and secondly to follow regular check-up for tendon pathology. PMID:27535258

  18. Sex Hormones and Tendon.

    PubMed

    Hansen, Mette; Kjaer, Michael

    2016-01-01

    The risk of overuse and traumatic tendon and ligament injuries differ between women and men. Part of this gender difference in injury risk is probably explained by sex hormonal differences which are specifically distinct during the sexual maturation in the teenage years and during young adulthood. The effects of the separate sex hormones are not fully elucidated. However, in women, the presence of estrogen in contrast to very low estrogen levels may be beneficial during regular loading of the tissue or during recovering after an injury, as estrogen can enhance tendon collagen synthesis rate. Yet, in active young female athletes, physiological high concentration of estrogen may enhance the risk of injuries due to reduced fibrillar crosslinking and enhanced joint laxity. In men, testosterone can enhance tendon stiffness due to an enhanced tendon collagen turnover and collagen content, but testosterone has also been linked to a reduced responsiveness to relaxin. The present chapter will focus on sex difference in tendon injury risk, tendon morphology and tendon collagen turnover, but also on the specific effects of estrogen and androgens. PMID:27535256

  19. 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

  20. Murine Flexor Tendon Injury and Repair Surgery.

    PubMed

    Ackerman, Jessica E; Loiselle, Alayna E

    2016-01-01

    Tendon connects skeletal muscle and bone, facilitating movement of nearly the entire body. In the hand, flexor tendons (FTs) enable flexion of the fingers and general hand function. Injuries to the FTs are common, and satisfactory healing is often impaired due to excess scar tissue and adhesions between the tendon and surrounding tissue. However, little is known about the molecular and cellular components of FT repair. To that end, a murine model of FT repair that recapitulates many aspects of healing in humans, including impaired range of motion and decreased mechanical properties, has been developed and previously described. Here an in-depth demonstration of this surgical procedure is provided, involving transection and subsequent repair of the flexor digitorum longus (FDL) tendon in the murine hind paw. This technique can be used to conduct lineage analysis of different cell types, assess the effects of gene gain or loss-of-function, and to test the efficacy of pharmacological interventions in the healing process. However, there are two primary limitations to this model: i) the FDL tendon in the mid-portion of the murine hind paw, where the transection and repair occur, is not surrounded by a synovial sheath. Therefore this model does not account for the potential contribution of the sheath to the scar formation process. ii) To protect the integrity of the repair site, the FT is released at the myotendinous junction, decreasing the mechanical forces of the tendon, likely contributing to increased scar formation. Isolation of sufficient cells from the granulation tissue of the FT during the healing process for flow cytometric analysis has proved challenging; cytology centrifugation to concentrate these cells is an alternate method used, and allows for generation of cell preparations on which immunofluorescent labeling can be performed. With this method, quantification of cells or proteins of interest during FT healing becomes possible. PMID:27684281

  1. Characterization of mechanical and biochemical properties of developing embryonic tendon.

    PubMed

    Marturano, Joseph E; Arena, Jeffrey D; Schiller, Zachary A; Georgakoudi, Irene; Kuo, Catherine K

    2013-04-16

    Tendons have uniquely high tensile strength, critical to their function to transfer force from muscle to bone. When injured, their innate healing response results in aberrant matrix organization and functional properties. Efforts to regenerate tendon are challenged by limited understanding of its normal development. Consequently, there are few known markers to assess tendon formation and parameters to design tissue engineering scaffolds. We profiled mechanical and biological properties of embryonic tendon and demonstrated functional properties of developing tendon are not wholly reflected by protein expression and tissue morphology. Using force volume-atomic force microscopy, we found that nano- and microscale tendon elastic moduli increase nonlinearly and become increasingly spatially heterogeneous during embryonic development. When we analyzed potential biochemical contributors to modulus, we found statistically significant but weak correlation between elastic modulus and collagen content, and no correlation with DNA or glycosaminoglycan content, indicating there are additional contributors to mechanical properties. To investigate collagen cross-linking as a potential contributor, we inhibited lysyl oxidase-mediated collagen cross-linking, which significantly reduced tendon elastic modulus without affecting collagen morphology or DNA, glycosaminoglycan, and collagen content. This suggests that lysyl oxidase-mediated cross-linking plays a significant role in the development of embryonic tendon functional properties and demonstrates that changes in cross-links alter mechanical properties without affecting matrix content and organization. Taken together, these data demonstrate the importance of functional markers to assess tendon development and provide a profile of tenogenic mechanical properties that may be implemented in tissue engineering scaffold design to mechanoregulate new tendon regeneration.

  2. Effects of freezing on the biomechanical and structural properties of human posterior tibial tendons

    PubMed Central

    Giannini, Sandro; Buda, Roberto; Agati, Patrizia; Bigi, Adriana; De Pasquale, Viviana; Ruggeri, Alessandro

    2007-01-01

    This work analyzes the effects of storage by fresh-freezing at −80°C on the histological, structural and biomechanical properties of the human posterior tibial tendon (PTT), used for ACL reconstruction. Twenty-two PTTs were harvested from eleven donors. For each donor one tendon was frozen at −80°C and thawed in physiological solution at 37°C, and the other was tested without freezing (control). Transmission electron microscopy (TEM), differential scanning calorimetry (DSC) and biomechanical analysis were performed. We found the following mean changes in frozen-thawed tendons compared to controls: TEM showed an increase in the mean diameter of collagen fibrils and in fibril non-occupation mean ratio, while the mean number of fibrils decreased; DSC showed a decrease in mean denaturation temperature and denaturation enthalpy. Biomechanical analysis showed a decrease in ultimate load and ultimate stress, an increase in stiffness and a decrease in ultimate strain of tendons. In conclusion fresh-freezing brings about significant changes in the biomechanical and structural properties of the human PTT. A high variability exists in the biophysical properties of tendons among individuals and in the effects of storage on tendons. Therefore, when choosing an allograft tendon, particular care is needed to choose a biomechanically suitable graft. PMID:17216243

  3. Whole-body vibration training induces hypertrophy of the human patellar tendon.

    PubMed

    Rieder, F; Wiesinger, H-P; Kösters, A; Müller, E; Seynnes, O R

    2016-08-01

    Animal studies suggest that regular exposure to whole-body vibration (WBV) induces an anabolic response in bone and tendon. However, the effects of this type of intervention on human tendon properties and its influence on the muscle-tendon unit function have never been investigated. The aim of this study was to investigate the effect of WBV training on the patellar tendon mechanical, material and morphological properties, the quadriceps muscle architecture and the knee extension torque-angle relationship. Fifty-five subjects were randomized into either a vibration, an active control, or an inactive control group. The active control subjects performed isometric squats on a vibration platform without vibration. Muscle and tendon properties were measured using ultrasonography and dynamometry. Vibration training induced an increase in proximal (6.3%) and mean (3.8%) tendon cross-sectional area, without any appreciable change in tendon stiffness and modulus or in muscle architectural parameters. Isometric torque at a knee angle of 90° increased in active controls (6.7%) only and the torque-angle relation remained globally unchanged in all groups. The present protocol did not appreciably alter knee extension torque production or the musculo-tendinous parameters underpinning this function. Nonetheless, this study shows for the first time that WBV elicits tendon hypertrophy in humans. PMID:26173589

  4. Middle-aged adults exhibit altered spatial variations in Achilles tendon wave speed

    PubMed Central

    Slane, Laura Chernak; DeWall, Ryan; Martin, Jack; Lee, Kenneth; Thelen, Darryl G.

    2016-01-01

    The purpose of this study was to investigate spatial variations in measured wave speed in the relaxed and stretched Achilles tendons of young and middle-aged adults. Wave speed was measured from the distal Achilles tendon, soleus aponeurosis, medial gastrocnemius aponeurosis and medial gastrocnemius muscle in healthy young (n = 15, aged 25 ± 4 years) and middle-aged (n = 10, aged 49 ± 4 years) adults in resting, dorsiflexed and plantarflexed postures. In both age groups, Achilles tendon wave speed decreased proximally, with the lowest wave speed measured in the gastrocnemius aponeurosis. Measured wave speed increased with passive dorsiflexion, reflecting the strain-stiffening behavior of tendons. There were no significant aging effects on wave speed in the free tendon or soleus aponeurosis. However, a significant, inverse relationship between gastrocnemius aponeurosis wave speed and age was observed in the dorsiflexed posture. We also observed significantly lower wave speeds in the gastrocnemius muscles of middle-aged adults when compared with young adults. These results suggest that Achilles tendon compliance increases in a distal-to-proximal pattern, with middle-aged adults exhibiting greater compliance in the distal gastrocnemius muscle and tendinous structures. An age-related change in the spatial variation in Achilles tendon compliance could affect localised tissue deformation patterns and injury potential within the triceps surae muscle-tendon units. PMID:26020294

  5. Alterations of tendons in diabetes mellitus: what are the current findings?

    PubMed

    Shi, Liu; Rui, Yun-Feng; Li, Gang; Wang, Chen

    2015-08-01

    As a connective tissue, tendon connects the muscle and bone, and plays the key role in the locomotor system. Some previous studies have shown the pathological alternations in diabetic tendons, which might result in the structural and functional changes, and even accelerate the process of diabetic foot. In this review, we examined the current findings of the diabetic tendons in the form of various aspects, and summarized the clinical presentation, imaging, biomechanical, histopathological, cellular and molecular abnormalities in the diabetic tendons. The progress of diabetic tendon damage is complicated and the main hypotheses include the excessive accumulation of AGEs, the altered inflammatory response, neovascularization and insensitive neuropathy. However, the cellular and molecular mechanisms of these alterations are still ambiguous. Tendon stem/progenitor cells (TSPCs) have been discovered to play important roles in both tendon physiology and tendon pathology. Recently, we identified TSPCs from patellar tendons in our well-established diabetic rat model and found impaired tenogenic differentiation potential of these cells. We proposed a new hypothesis that the impaired cell functions of diabetic TSPCs might be the underlying cellular and molecular mechanism of the diabetic tendon alternations. These findings should be helpful to establish a better therapeutic strategy for diabetic tendon repair and regeneration.

  6. 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

  7. Tendon Extracellular Matrix Alterations in Ullrich Congenital Muscular Dystrophy

    PubMed Central

    Sardone, Francesca; Traina, Francesco; Bondi, Alice; Merlini, Luciano; Santi, Spartaco; Maraldi, Nadir Mario; Faldini, Cesare; Sabatelli, Patrizia

    2016-01-01

    Collagen VI (COLVI) is a non-fibrillar collagen expressed in skeletal muscle and most connective tissues. Mutations in COLVI genes cause two major clinical forms, Bethlem myopathy and Ullrich congenital muscular dystrophy (UCMD). In addition to congenital muscle weakness, patients affected by COLVI myopathies show axial and proximal joint contractures and distal joint hypermobility, which suggest the involvement of the tendon function. We examined a peroneal tendon biopsy and tenocyte culture of a 15-year-old patient affected by UCMD with compound heterozygous COL6A2 mutations. In patient’s tendon biopsy, we found striking morphological alterations of tendon fibrils, consisting in irregular profiles and reduced mean diameter. The organization of the pericellular matrix of tenocytes, the primary site of collagen fibril assembly, was severely affected, as determined by immunoelectron microscopy, which showed an abnormal accumulation of COLVI and altered distribution of collagen I (COLI) and fibronectin (FBN). In patient’s tenocyte culture, COLVI web formation and cell surface association were severely impaired; large aggregates of COLVI, which matched with COLI labeling, were frequently detected in the extracellular matrix. In addition, metalloproteinase MMP-2, an extracellular matrix-regulating enzyme, was increased in the conditioned medium of patient’s tenocytes, as determined by gelatin zymography and western blot. Altogether, these data indicate that COLVI deficiency may influence the organization of UCMD tendon matrix, resulting in dysfunctional fibrillogenesis. The alterations of tendon matrix may contribute to the complex pathogenesis of COLVI related myopathies. PMID:27375477

  8. The anatomical footprint of the Achilles tendon: a cadaveric study.

    PubMed

    Ballal, M S; Walker, C R; Molloy, A P

    2014-10-01

    We dissected 12 fresh-frozen leg specimens to identify the insertional footprint of each fascicle of the Achilles tendon on the calcaneum in relation to their corresponding muscles. A further ten embalmed specimens were examined to confirm an observation on the retrocalcaneal bursa. The superficial part of the insertion of the Achilles tendon is represented by fascicles from the medial head of the gastrocnemius muscle, which is inserted over the entire width of the inferior facet of the calcaneal tuberosity. In three specimens this insertion was in continuity with the plantar fascia in the form of periosteum. The deep part of the insertion of the Achilles tendon is made of fascicles from the soleus tendon, which insert on the medial aspect of the middle facet of the calcaneal tuberosity, while the fascicles of the lateral head of the gastrocnemius tendon insert on the lateral aspect of the middle facet of the calcaneal tuberosity. A bicameral retrocalcaneal bursa was present in 15 of the 22 examined specimens. This new observation and description of the insertional footprint of the Achilles tendon and the retrocalcaneal bursa may allow a better understanding of the function of each muscular part of the gastrosoleus complex. This may have clinical relevance in the treatment of Achilles tendinopathies.

  9. Tendon Extracellular Matrix Alterations in Ullrich Congenital Muscular Dystrophy.

    PubMed

    Sardone, Francesca; Traina, Francesco; Bondi, Alice; Merlini, Luciano; Santi, Spartaco; Maraldi, Nadir Mario; Faldini, Cesare; Sabatelli, Patrizia

    2016-01-01

    Collagen VI (COLVI) is a non-fibrillar collagen expressed in skeletal muscle and most connective tissues. Mutations in COLVI genes cause two major clinical forms, Bethlem myopathy and Ullrich congenital muscular dystrophy (UCMD). In addition to congenital muscle weakness, patients affected by COLVI myopathies show axial and proximal joint contractures and distal joint hypermobility, which suggest the involvement of the tendon function. We examined a peroneal tendon biopsy and tenocyte culture of a 15-year-old patient affected by UCMD with compound heterozygous COL6A2 mutations. In patient's tendon biopsy, we found striking morphological alterations of tendon fibrils, consisting in irregular profiles and reduced mean diameter. The organization of the pericellular matrix of tenocytes, the primary site of collagen fibril assembly, was severely affected, as determined by immunoelectron microscopy, which showed an abnormal accumulation of COLVI and altered distribution of collagen I (COLI) and fibronectin (FBN). In patient's tenocyte culture, COLVI web formation and cell surface association were severely impaired; large aggregates of COLVI, which matched with COLI labeling, were frequently detected in the extracellular matrix. In addition, metalloproteinase MMP-2, an extracellular matrix-regulating enzyme, was increased in the conditioned medium of patient's tenocytes, as determined by gelatin zymography and western blot. Altogether, these data indicate that COLVI deficiency may influence the organization of UCMD tendon matrix, resulting in dysfunctional fibrillogenesis. The alterations of tendon matrix may contribute to the complex pathogenesis of COLVI related myopathies. PMID:27375477

  10. What We Should Know Before Using Tissue Engineering Techniques to Repair Injured Tendons: A Developmental Biology Perspective

    PubMed Central

    Liu, Chia-Feng; Aschbacher-Smith, Lindsey; Barthelery, Nicolas J.; Dyment, Nathaniel; Butler, David

    2011-01-01

    Tendons connect muscles to bones, and serve as the transmitters of force that allow all the movements of the body. Tenocytes are the basic cellular units of tendons, and produce the collagens that form the hierarchical fiber system of the tendon. Tendon injuries are common, and difficult to repair, particularly in the case of the insertion of tendon into bone. Successful attempts at cell-based repair therapies will require an understanding of the normal development of tendon tissues, including their differentiated regions such as the fibrous mid-section and fibrocartilaginous insertion site. Many genes are known to be involved in the formation of tendon. However, their functional roles in tendon development have not been fully characterized. Tissue engineers have attempted to generate functional tendon tissue in vitro. However, a lack of knowledge of normal tendon development has hampered these efforts. Here we review studies focusing on the developmental mechanisms of tendon development, and discuss the potential applications of a molecular understanding of tendon development to the treatment of tendon injuries. PMID:21314435

  11. Patellar tendon properties with fluctuating menstrual cycle hormones.

    PubMed

    Burgess, Katherine E; Pearson, Stephen J; Onambélé, Gladys L

    2010-08-01

    Debate continues over whether skeletal muscle performance and injury risk vary over the course of the menstrual cycle. Alterations in tendon properties may play a role in the potential fluctuations of both of these variables. The aim of the current study was to determine any association between menstrual cycle phase and corresponding levels of female sex hormones and tendon properties. Fifteen normally menstruating (28-32-day cycles) healthy females (age 23 +/- 1 years, mass 63.1 +/- 2.6 kg, height 1.66 +/- 0.02 m) not taking any form of hormonal contraceptive took part in this study. In vivo patellar tendon properties and associated circulating hormonal levels were assessed on 3 occasions including days 3 +/- 0.4, 13 +/- 0.2, and 21 +/- 0.3. Dynamometry, ultrasonography, electromyography, and biochemical assessment of circulating levels of estradiol and progesterone were utilized. No significant differences were seen in tendon mechanical properties among the 3 phases of the menstrual cycle (p > 0.05). Regressions were carried out and revealed that estrogen and maximal voluntary tendon force explained 17.8% (p = 0.043) of the variance in young's modulus. Our findings link estrogen to a chronic, rather than an acute, impact on tendon behavior. These findings are relevant to clinical outcomes, exercise performance, and injury risk. In terms of tendon properties, menstrual cycle phase does not necessarily need to be considered when organizing training and competition schedules.

  12. Freeze-dried microarterial allografts

    SciTech Connect

    Raman, J.; Hargrave, J.C.

    1990-02-01

    Rehydrated freeze-dried microarterial allografts were implanted to bridge arterial defects using New Zealand White rabbits as the experimental model. Segments of artery from the rabbit ear and thigh were harvested and preserved for a minimum of 2 weeks after freeze-drying. These allografts, approximately 1 mm in diameter and ranging from 1.5 to 2.5 cm in length, were rehydrated and then implanted in low-pressure and high-pressure arterial systems. Poor patency was noted in low-pressure systems in both allografts and autografts, tested in 12 rabbits. In the high-pressure arterial systems, allografts that were freeze-dried and reconstituted failed in a group of 10 rabbits with an 8-week patency rate of 30 percent. Gamma irradiation in an effort to reduce infection and antigenicity of grafts after freeze-drying was associated with a patency rate of 10 percent at 8 weeks in this system in another group of 10 rabbits. Postoperative cyclosporin A therapy was associated with a patency rate of 22.2 percent in the high-pressure arterial system in a 9-rabbit group. Control autografts in this system in a group of 10 rabbits showed a 100 percent patency at 8 weeks. Microarterial grafts depend on perfusion pressure of the vascular bed for long-term patency. Rehydrated freeze-dried microarterial allografts do not seem to function well in lengths of 1 to 2.5 cm when implanted in a high-pressure arterial system. Freeze-dried arterial allografts are probably not antigenic.

  13. 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.

  14. 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

  15. Wrist and digital joint motion produce unique flexor tendon force and excursion in the canine forelimb.

    PubMed

    Lieber, R L; Silva, M J; Amiel, D; Gelberman, R H

    1999-02-01

    The force and excursion within the canine digital flexor tendons were measured during passive joint manipulations that simulate those used during rehabilitation after flexor tendon repair and during active muscle contraction, simulating the active rehabilitation protocol. Tendon force was measured using a small buckle placed upon the tendon while excursion was measured using a suture marker and video analysis method. Passive finger motion imposed with the wrist flexed resulted in dramatically lower tendon force (approximately 5 N) compared to passive motion imposed with the wrist extended (approximately 17 N). Lower excursions were seen at the level of the proximal interphalangeal joint with the wrist flexed (approximately 1.5 mm) while high excursion was observed when the wrist was extended or when synergistic finger and wrist motion were imposed (approximately 3.5 mm). Bivariate discriminant analysis of both force and excursion data revealed a natural clustering of the data into three general mechanical paradigms. With the wrist extended and with either one finger or four fingers manipulated, tendons experienced high loads of approximately 1500 g and high excursions of approximately 3.5 mm. In contrast, the same manipulations performed with the wrist flexed resulted in low tendon forces (4-8 N) and low tendon excursions of approximately 1.5 mm. Synergistic wrist and finger manipulation provided the third paradigm where tendon force was relatively low (approximately 4 N) but excursion was as high as those seen in the groups which were manipulated with the wrist extended. Active muscle contraction produced a modest tendon excursion (approximately 1 mm) and high or low tendon force with the wrist extended or flexed, respectively. These data provide the basis for experimentally testable hypotheses with regard to the factors that most significantly affect functional recovery after digital flexor tendon injury and define the normal mechanical operating characteristics

  16. Reconstruction of chronic patellar tendon rupture with contralateral BTB autograft: a case report.

    PubMed

    Milankov, Miroslav Z; Miljkovic, Natasa; Stankovic, Milan

    2007-12-01

    Chronic patellar tendon rupture is a rare disabling injury that is technically difficult to repair. Many different surgical methods have been reported for the reconstruction of chronic patellar tendon ruptures. We are reporting the use of contralateral bone-tendon-bone (BTB) autograft for chronic patellar tendon rupture reconstruction followed by double-wire loop reinforcement and without postoperative immobilization. One year after the operation, our patient had full knee extension and up to 130 degrees of flexion. He had good quadriceps strength, and isokinetic muscle testing showed no deficit comparing to his right leg. Patient returned to playing basketball in his spare time, without having any limitation.

  17. Singling out Drosophila tendon cells: a dialogue between two distinct cell types.

    PubMed

    Volk, T

    1999-11-01

    The precise match between somatic muscles and their epidermal attachment cells is achieved through a continuous dialogue between these two cell types. Whereas tendon cells direct myotube migration and final patterning, the muscles are essential for the maintenance of the fate of tendon cells. The Drosophila neuregulin-like ligand, Vein, and its receptor, the epidermal growth factor receptor (Egfr), are critical components in the inductive signaling process that takes place between muscles and tendon cells. Additional gene products that relay the Vein-Egfr effect in Drosophila are conserved in the vertebrate neuregulin-mediated cascade. This review describes genetic and molecular aspects of the muscle-tendon inductive processes in Drosophila, and compares them with the relevant mechanisms in the vertebrate embryo.

  18. Unusual fibularis (peroneus) muscle.

    PubMed

    Fabrizio, Philip A

    2015-10-01

    Routine dissection has identified a previously unrecorded fibularis (peroneus) muscle in a 74-year-old male cadaver. The anomalous fibularis muscle was found lying immediately antero-medial to the fibularis longus (FL) muscle of the left leg. The anomalous muscle arose from the muscle belly of the FL in the proximal 1/2 of the leg. The muscle belly gave way to a long slender tendon that continued distally behind the lateral malleolus and inserted onto the superficial aspect of the inferior fibular retinaculum. The current finding and clinical significance are discussed.

  19. Systemic overexpression of matricellular protein CCN1 exacerbates obliterative bronchiolitis in mouse tracheal allografts.

    PubMed

    Raissadati, Alireza; Nykänen, Antti I; Tuuminen, Raimo; Syrjälä, Simo O; Krebs, Rainer; Arnaudova, Ralica; Rouvinen, Eeva; Wang, Xiaomin; Poller, Wolfgang; Lemström, Karl B

    2015-12-01

    Obliterative bronchiolitis (OB) involves airway epithelial detachment, fibroproliferation, and inflammation, resulting in chronic rejection and transplant failure. Cysteine-rich 61 (CCN1) is an integrin receptor antagonist with a context-dependent role in inflammatory and fibroproliferative processes. We used a mouse tracheal OB model to investigate the role of CCN1 in the development of lung allograft OB. C57Bl/6 mice received a systemic injection of CCN1-expressing adenoviral vectors 2 days prior to subcutaneous implantation of tracheal allografts from major MHC-mismatched BALB/c mice. We treated another group of tracheal allograft recipients with cyclic arginine-glycine-aspartic acid peptide to dissect the role of αvβ3-integrin signaling in mediating CCN1 effects in tracheal allografts. Allografts were removed 4 weeks after transplantation and analyzed for luminal occlusion, inflammation, and vasculogenesis. CCN1 overexpression induced luminal occlusion (P < 0.05), fibroproliferation, and smooth muscle cell proliferation (P < 0.05). Selective activation of αvβ3-integrin receptor failed to mimic the actions of CCN1, and blocking failed to inhibit the effects of CCN1 in tracheal allografts. In conclusion, CCN1 exacerbates tracheal OB by enhancing fibroproliferation via an αvβ3-integrin-independent pathway. Further experiments are required to uncover its potentially harmful role in the development of OB after lung transplantation.

  20. [Simultaneous rupture of a patellar tendon and contralateral quadriceps tendon].

    PubMed

    Horas, U; Ernst, S; Meyer, C; Halbsguth, A; Herbst, U

    2006-09-01

    The simultaneous bilateral rupture of the quadriceps tendon is a rare injury; only occasional reports exist about the bilateral simultaneous rupture of the patellar tendon. Degenerative changes of the tendon due to drugs or diseases lead to the rupture. We describe two cases of simultaneous rupture of the patellar and contralateral quadriceps tendons; only one patient had special risks. We report the management of therapy and the functional results using the Lysholm score and Knee Rating Scale.

  1. Age-related fascicle-tendon interaction in repetitive hopping.

    PubMed

    Hoffrén, Merja; Ishikawa, Masaki; Avela, Janne; Komi, Paavo V

    2012-12-01

    Increasing age can influence the interaction of muscle fascicles and tendon during dynamic movements. The object of the present study was to examine occurrence and possible reasons for the age-specific behavior of fascicles and tendons and their interaction during hopping with different intensities. Nine young and 24 elderly subjects performed repetitive hopping with maximal effort as well as with 50, 65, 75 and 90 % intensities. During hopping joint kinematics and ground reaction, forces were measured together with recordings of ultrasound images of both the fascicle and the muscle-tendon junction part of the gastrocnemius medialis (GaM) muscle. The results showed that fascicle behavior during the braking phase of hopping was clearly age specific in nature with more fascicle shortening in the young (p < 0.001). In addition, the fascicle shortening increased in young subjects with increasing intensity (p < 0.05). At the instant of ground contact, the elderly subjects demonstrated decreased fascicle length with increasing hopping intensity (p < 0.01). Thereafter in the braking phase, the elderly showed much smaller changes in fascicle length as compared to the young. In contrast to the fascicles, the GaM outer tendon did not show major age-specific differences in stretching and shortening amplitudes during hopping although the peak tendon forces were clearly lower in the elderly (p < 0.001). These results suggest that GaM outer tendon behavior is not influenced greatly with increasing age. It is further suggested that when aging modifies the fascicle-tendon interaction, it is primarily due to the age-specific difference in the fascicle level. This notion poses a question that as compared to the young, the elderly individuals may have a different fascicle behavior for optimal SSC locomotion such as hopping.

  2. Lack of tissue renewal in human adult Achilles tendon is revealed by nuclear bomb (14)C.

    PubMed

    Heinemeier, Katja Maria; Schjerling, Peter; Heinemeier, Jan; Magnusson, Stig Peter; Kjaer, Michael

    2013-05-01

    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 (14)C bomb-pulse method. This method takes advantage of the dramatic increase in atmospheric levels of (14)C, produced by nuclear bomb tests in 1955-1963, which is reflected in all living organisms. Levels of (14)C 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 (14)C corresponding to atmospheric levels several decades before tissue sampling, demonstrating a very limited tissue turnover. The tendon concentrations of (14)C 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, (14)C 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.

  3. Emphysema in the renal allograft

    SciTech Connect

    Potter, J.L.; Sullivan, B.M.; Fluornoy, J.G.; Gerza, C.

    1985-04-01

    Two diabetic patients in whom emphysematous pyelonephritis developed after renal transplantation are described. Clinical recognition of this unusual and serious infection is masked by the effects of immunosuppression. Abdominal radiographic, ultrasound, and computed tomography findings are discussed. The clinical presentation includes urinary tract infection, sepsis, and acute tubular malfunction of the allograft in insulin-dependent diabetics.

  4. [Quadriceps and patellar tendon ruptures].

    PubMed

    Grim, C; Lorbach, O; Engelhardt, M

    2010-12-01

    Ruptures of the quadriceps or patellar tendon are uncommon but extremely relevant injuries. Early diagnosis and surgical treatment with a stable suture construction are mandatory for a good postoperative clinical outcome. The standard methods of repair for quadriceps and patellar tendon injuries include the placement of suture loops through transpatellar tunnels. Reinforcement with either a wire cerclage or a PDS cord is used in patellar tendon repair. The PDS cord can also be applied as augmentation in quadriceps tendon repair. In secondary patellar tendon repair an autologous semitendinosus graft can be used. For chronic quadriceps tendon defects a V-shaped tendon flap with a distal footing is recommended. The different methods of repair should lead to early functional postoperative treatment. The clinical outcome after surgical treatment of patellar and quadriceps tendon ruptures is mainly good.

  5. Effects of mechanical vibration of the foot sole and ankle tendons on cutaneomuscular responses in man.

    PubMed

    Smith, Andrew C; Mummidisetty, Chaithanya K; Rymer, William Zev; Knikou, Maria

    2013-06-17

    The modulation of cutaneomuscular responses in response to mechanical vibration applied to the foot sole and to the ankle tendons was established in ten healthy subjects. The effects of mechanical vibration applied to the skin adjacent to the tibialis anterior (TA) and Achilles tendons were examined in two subjects. With the subjects seated, mechanical vibration applied to the TA and/or Achilles tendons significantly depressed the cutaneomuscular responses in all subjects, regardless of the frequency (50, 150, 250 Hz) of vibration. Mechanical vibration applied either to the foot sole or to the skin adjacent to the tendons induced no significant effects. The demonstration that mechanical vibration applied to muscle tendons exerts an inhibitory effect on cutaneomuscular responses supports the hypothesis that receptors that mediate body kinesthesia can be used as a vehicle to alter the spinal excitability state. The data suggests that tendon vibration could be utilized in neurological disorders to induce exogenous-mediated potentiation of presynaptic inhibition.

  6. Hyperuricemia in Tendons.

    PubMed

    Andia, Isabel; Abate, Michele

    2016-01-01

    Hyperuricemia, particularly gout, and the immune inflammatory response are highly integrated. Both, long standing hyperuricemia and monosodium urate (MSU) crystal deposition can challenge tendon homeostasis because of their potential to cause inflammation to the host. Knowledge is emerging from clinical imaging research depicting where MSU crystals deposit, including patellar tendon, triceps and quadriceps tendons. Remarkably, subclinical tendon inflammation and damage are also present in asymptomatic hyperuricemia. Monosodium urate crystals act as danger activating molecular patterns (DAMPs), activating the inflammasome and inducing the secretion of IL-1beta, a key mediator of the inflammatory response. The crucial role of IL-1beta in driving the inflammatory events during gout attacks is supported by the clinical efficacy of IL-1beta blockade. Some data implicating IL-1beta as an initiator of tendinopathy exist, but the link between hyperuricemia and the development of tendinopathy remains to be validated. Further knowledge about the interactions of uric acid with both innate immune and tendon cells, and their consequences may help to determine if there is a subclass of hyperuricemic-tendinopathy. PMID:27535254

  7. Left ventricular false tendons: anatomic, echocardiographic, and pathophysiologic insights.

    PubMed

    Silbiger, Jeffrey J

    2013-06-01

    Left ventricular (LV) false tendons are chordlike structures that traverse the LV cavity. They attach to the septum, to the papillary muscles, or to the free wall of the ventricle but not to the mitral valve. They are found in approximately half of human hearts examined at autopsy. Although it has been more than 100 years since their initial description, the functional significance of these structures remains largely unexplored. It has been suggested that they retard LV remodeling by tethering the walls to which they are attached, but there are few data to substantiate this. Some studies have suggested that false tendons reduce the severity of functional mitral regurgitation by stabilizing the position of the papillary muscles as the left ventricle enlarges. LV false tendons may also have deleterious effects and have been implicated in promoting membrane formation in discrete subaortic stenosis. This article reviews current understanding of the anatomy, echocardiographic characteristics, and pathophysiology of these structures.

  8. Fractionation of 50kGy electron beam irradiation: effects on biomechanics of human flexor digitorum superficialis tendons treated with ascorbate.

    PubMed

    Wei, Wei; Liu, Yujie; Yang, Xu; Tian, Shaoqi; Liu, Chao; Zhang, Yang; Xu, Zhaoning; Hu, Baiqiang; Tian, Zhen; Sun, Kang

    2013-02-22

    The electron beam (Ebeam) irradiation has begun to be considered as an efficient alternative to gamma irradiation in the sterilization of allografts in the reconstruction of anterior cruciate ligament. The purpose of this study was to evaluate the biomechanical properties of human tendons after exposure to electron beam and free radical scavenger ascorbate. Forty human flexor digitorum superficialis tendons were prepared from five fresh cadavers and divided randomly into four groups: A, fresh (0kGy); B, 50kGy Ebeam irradiation; C, fractionated 50kGy Ebeam irradiation; D, fractionated 50kGy Ebeam on ascorbate-treated tendons. The fractionation of 50kGy was achieved by repeated irradiation of 2.5kGy for 20 repetitions. Biomechanical properties were analyzed during load-to-failure testing. The fresh tendons were found to be significant different in ultimate load, ultimate elongation relative to tendons in group B. Statistical differences were found between group B and C in ultimate load. No differences were detected between group A and C in all the parameters. Compare tendons in group C and D, significant differences were found in ultimate load and ultimate stress. It is recommended that fractionated 50kGy electron beam irradiation and free radical scavenger ascorbate should be applied in the sterilization of allografts tendons.

  9. 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.

  10. Power amplification in an isolated muscle–tendon unit is load dependent

    PubMed Central

    Sawicki, Gregory S.; Sheppard, Peter; Roberts, Thomas J.

    2015-01-01

    ABSTRACT During rapid movements, tendons can act like springs, temporarily storing work done by muscles and then releasing it to power body movements. For some activities, such as frog jumping, energy is released from tendon much more rapidly than it is stored, thus amplifying muscle power output. The period during which energy is loaded into a tendon by muscle work may be aided by a catch mechanism that restricts motion, but theoretical studies indicate that power can be amplified in a muscle–tendon load system even in the absence of a catch. To explore the limits of power amplification with and without a catch, we studied the bullfrog plantaris muscle–tendon during in vitro contractions. A novel servomotor controller allowed us to measure muscle–tendon unit (MTU) mechanical behavior during contractions against a variety of simulated inertial-gravitational loads, ranging from zero to 1× the peak isometric force of the muscle. Power output of the MTU system was load dependent and power amplification occurred only at intermediate loads, reaching ∼1.3× the peak isotonic power output of the muscle. With a simulated anatomical catch mechanism in place, the highest power amplification occurred at the lowest loads, with a maximum amplification of more than 4× peak isotonic muscle power. At higher loads, the benefits of a catch for MTU performance diminished sharply, suggesting that power amplification >2.5× may come at the expense of net mechanical work delivered to the load. PMID:26449973

  11. Adaptive Remodeling of Achilles Tendon: A Multi-scale Computational Model

    PubMed Central

    Rubenson, Jonas; Umberger, Brian

    2016-01-01

    While it is known that musculotendon units adapt to their load environments, there is only a limited understanding of tendon adaptation in vivo. Here we develop a computational model of tendon remodeling based on the premise that mechanical damage and tenocyte-mediated tendon damage and repair processes modify the distribution of its collagen fiber lengths. We explain how these processes enable the tendon to geometrically adapt to its load conditions. Based on known biological processes, mechanical and strain-dependent proteolytic fiber damage are incorporated into our tendon model. Using a stochastic model of fiber repair, it is assumed that mechanically damaged fibers are repaired longer, whereas proteolytically damaged fibers are repaired shorter, relative to their pre-damage length. To study adaptation of tendon properties to applied load, our model musculotendon unit is a simplified three-component Hill-type model of the human Achilles-soleus unit. Our model results demonstrate that the geometric equilibrium state of the Achilles tendon can coincide with minimization of the total metabolic cost of muscle activation. The proposed tendon model independently predicts rates of collagen fiber turnover that are in general agreement with in vivo experimental measurements. While the computational model here only represents a first step in a new approach to understanding the complex process of tendon remodeling in vivo, given these findings, it appears likely that the proposed framework may itself provide a useful theoretical foundation for developing valuable qualitative and quantitative insights into tendon physiology and pathology. PMID:27684554

  12. Neuronal regulation of tendon homoeostasis.

    PubMed

    Ackermann, Paul W

    2013-08-01

    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.

  13. 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

  14. Computed tomography in the evaluation of Brown syndrome of the superior oblique tendon sheath

    SciTech Connect

    Mafee, M.F.; Folk, E.R.; Langer, B.G.; Miller, M.T.; Lagouros, P.; Mittleman, D.

    1985-03-01

    Computed tomographic (CT) findings in 4 patients with superior oblique tendon sheath syndrome (congenital or acquired Brown syndrome) are described. When the inferior oblique muscle moves the eye upward, the superior oblique muscle normally relaxes, while its tendon lengthens and slides freely through the trochlea. In Brown syndrome this process is somehow restricted, which is most apparent during attempts at elevation when the eye is adducted, resulting in an apparent inferior oblique palsy (pseudopalsy). CT is a valuable tool in understanding the pathophysiology and management of acquired Brown syndrome, showing thickening and inflammatory changes of the reflected portion of the superior oblique tendon.

  15. Outcome following addition of peroneus brevis tendon transfer to treatment of acquired posterior tibial tendon insufficiency.

    PubMed

    Song, S J; Deland, J T

    2001-04-01

    The flexor digitorum longus, the tendon most often used for transfer in posterior tibial tendon insufficiency, is one-half to one-third the size of the posterior tibial tendon. Occasionally it may be particularly small or may have been previously used for transfer. In these cases, the senior author has felt that the addition of a transfer of the Peroneus Brevis (PBr) tendon may be helpful in maintaining sufficient tendon and muscle mass to rebalance the foot. Thirteen patients who underwent this procedure were retrospectively identified and matched by age and length of follow-up to patients who underwent a more standard tendon transfer operation minus the addition of the PBr transfer. Pain and functional status were then assessed by the American Orthopaedic Foot and Ankle Society's ankle/hindfoot rating scale. Each patient was tested by an independent physical therapist to evaluate inversion and eversion strength. The mean duration of follow-up was 20.6 months (12 to 34 months). The average AOFAS score of the PBr group was 75.8 compared to 71.5 for the standard control group. There was no significant difference between the groups when inversion or eversion strengths were compared. Inversion strength and eversion strength was rated good or excellent (4 or 5) in 12 out of 13 of the PBr transfer group patients. No major complications were encountered in either group. Although it does not increase inversion strength, a PBr transfer can be used to augment a small FDL without causing significant eversion weakness. This can be useful when the FDL is particularly small or in revision surgery. PMID:11354442

  16. 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

  17. 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

  18. Microwave sterilization of femoral head allograft.

    PubMed

    Dunsmuir, Robert A; Gallacher, Grace

    2003-10-01

    The potential shortage of allograft bone has led to the need to investigate other sources of bone for allografts. Some allograft bone donated from primary total hip arthroplasty recipients must be discarded or treated to become usable as a result of bacterial contamination. Femoral head allografts were contaminated with Staphylococcus aureus and Bacillus subtilis. A domestic microwave oven was used. The contaminated bone was exposed to microwave irradiation for different time periods. The samples were then cultured to attempt to grow the two bacterial species. The contaminated bone samples failed to grow any organisms after 2 min of exposure to microwave irradiation. This study shows that sterilization of femoral head allografts contaminated with S. aureus and B. subtilis can be achieved with microwave irradiation in a domestic microwave oven. This method of sterilization of bone allografts is cheap, easily used, and an effective way to process contaminated bone. PMID:14532216

  19. Tendon reflex is suppressed during whole-body vibration.

    PubMed

    Karacan, Ilhan; Cidem, Muharrem; Yilmaz, Gizem; Sebik, Oguz; Cakar, Halil Ibrahim; Türker, Kemal Sıtkı

    2016-10-01

    In this study we have investigated the effect of whole body vibration (WBV) on the tendon reflex (T-reflex) amplitude. Fifteen young adult healthy volunteer males were included in this study. Records of surface EMG of the right soleus muscle and accelerometer taped onto the right Achilles tendon were obtained while participant stood upright with the knees in extension, on the vibration platform. Tendon reflex was elicited before and during WBV. Subjects completed a set of WBV. Each WBV set consisted of six vibration sessions using different frequencies (25, 30, 35, 40, 45, 50Hz) applied randomly. In each WBV session the Achilles tendon was tapped five times with a custom-made reflex hammer. The mean peak-to-peak (PP) amplitude of T-reflex was 1139.11±498.99µV before vibration. It decreased significantly during WBV (p<0.0001). The maximum PP amplitude of T-reflex was 1333±515μV before vibration. It decreased significantly during WBV (p<0.0001). No significant differences were obtained in the mean acceleration values of Achilles tendon with tapping between before and during vibration sessions. This study showed that T-reflex is suppressed during WBV. T-reflex suppression indicates that the spindle primary afferents must have been pre-synaptically inhibited during WBV similar to the findings in high frequency tendon vibration studies. PMID:27485766

  20. Tendon reflex is suppressed during whole-body vibration.

    PubMed

    Karacan, Ilhan; Cidem, Muharrem; Yilmaz, Gizem; Sebik, Oguz; Cakar, Halil Ibrahim; Türker, Kemal Sıtkı

    2016-10-01

    In this study we have investigated the effect of whole body vibration (WBV) on the tendon reflex (T-reflex) amplitude. Fifteen young adult healthy volunteer males were included in this study. Records of surface EMG of the right soleus muscle and accelerometer taped onto the right Achilles tendon were obtained while participant stood upright with the knees in extension, on the vibration platform. Tendon reflex was elicited before and during WBV. Subjects completed a set of WBV. Each WBV set consisted of six vibration sessions using different frequencies (25, 30, 35, 40, 45, 50Hz) applied randomly. In each WBV session the Achilles tendon was tapped five times with a custom-made reflex hammer. The mean peak-to-peak (PP) amplitude of T-reflex was 1139.11±498.99µV before vibration. It decreased significantly during WBV (p<0.0001). The maximum PP amplitude of T-reflex was 1333±515μV before vibration. It decreased significantly during WBV (p<0.0001). No significant differences were obtained in the mean acceleration values of Achilles tendon with tapping between before and during vibration sessions. This study showed that T-reflex is suppressed during WBV. T-reflex suppression indicates that the spindle primary afferents must have been pre-synaptically inhibited during WBV similar to the findings in high frequency tendon vibration studies.

  1. Posterior Tibialis Tendon Dysfunction: Overview of Evaluation and Management.

    PubMed

    Yao, Kaihan; Yang, Timothy Xianyi; Yew, Wei Ping

    2015-06-01

    EDUCATIONAL OBJECTIVES As a result of reading this article, physicians should be able to: 1. Recognize posterior tibialis tendon dysfunction and begin to include it in differential diagnoses. 2. Recall the basic anatomy and pathology of the posterior tibialis tendon. 3. Assess a patient for posterior tibialis tendon dysfunction with the appropriate investigations and stratify the severity of the condition. 4. Develop and formulate a treatment plan for a patient with posterior tibialis tendon dysfunction. The posterior tibialis is a muscle in the deep posterior compartment of the calf that plays several key roles in the ankle and foot. Posterior tibialis tendon dysfunction is a complex but common and debilitating condition. Degenerative, inflammatory, functional, and traumatic etiologies have all been proposed. Despite being the leading cause of acquired flatfoot, it is often not recognized early enough. Knowledge of the anatomical considerations and etiology of posterior tibialis tendon dysfunction, as well as key concepts in its evaluation and management, will allow health care professionals to develop appropriate intervention strategies to prevent further development of flatfoot deformities. PMID:26091214

  2. 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

  3. Should we think about wrist extensor after flexor tendon repair?

    PubMed Central

    Ferreira, Aline M; Tanaka, Denise M; Barbosa, Rafael I; Marcolino, Alexandre M; Elui, Valeria MC; Mazzer, Nilton

    2013-01-01

    Objective: To evaluate the activity of wrist extensor muscle, correlating with wrist motion during gripping after flexor tendon repair. Design: Cross-sectional clinical measurement study. Setting: Laboratory for biomechanics and rehabilitation. Subjects: A total of 11 patients submitted to rehabilitation by early passive motion of the fingers with wrist flexion position were evaluated after 8 weeks of fingers flexor tendon repair and 11 healthy volunteers, all ranging from 20 to 37 years of age. Intervention: Volunteers performed an isometric standardized gripping task. Main measures: We used electrogoniometry to analyze wrist range of motion and surface electromyography, considering 100% maximum voluntary contraction to represent the amplitude of electromyographic activity of the extensor carpi radialis and flexor digitorum superficialis. Results: Patients with flexor tendon repair showed co-activation deficit between wrist extensor (extensor carpi radialis) and flexor finger muscles (flexor digitorum superficialis) during gripping in the intermediate phase of rehabilitation, despite some recovering mobility for wrist extension (p ≤ 0.05). A moderate correlation between range of motion and extensor carpi radialis was present only for injured group (r = 0.32). Total active motion score, which represents finger active excursion, was regular or poor in 65% of cases, all with nerve repair associated. Conclusion: Wrist extensors have an important synergist role at handgrip, although some imbalance can be present after flexor tendon repair. These preliminary findings suggest that emphasis could be directed to add synergistic wrist motion in rehabilitation protocols after flexor tendon repair. Future studies with early active rehabilitation are necessary. PMID:26770674

  4. Arthroscopic treatment of infrapatellar tendonitis.

    PubMed

    Romeo, A A; Larson, R V

    1999-04-01

    Infrapatellar tendonitis is a chronic overload lesion in the patellar ligament at the attachment to the lower pole of the patella. This lesion is found primarily in athletes who participate in jumping sports. Magnetic resonance imaging or ultrasound can show the extent of tendon pathology. Patellar tendonitis is treated with modification of activities, medications, and therapy. When conservative measures fail, operative debridement has been recommended. Previous reports have described a technique of open debridement of the patellar tendon, followed by an extended period of rehabilitation before returning to sports. Two athletes with persistent infrapatellar tendonitis were treated with an arthroscopic debridement. Both athletes returned to full activities without restrictions within 8 weeks of surgery. Arthroscopic treatment of infrapatellar tendonitis has not been previously described. This technical note describes the technique and two case reports of the arthroscopic treatment of infrapatellar tendonitis.

  5. Myofascial force transmission between transferred rat flexor carpi ulnaris muscle and former synergistic palmaris longus muscle

    PubMed Central

    Maas, Huub; Huijing, Peter A.

    2011-01-01

    Summary We investigated the extent of mechanical interaction between rat flexor carpi ulnaris (FCU) and palmaris longus (PL) muscles following transfer of FCU to the distal tendons of extensor carpi radialis brevis and longus (ECRB/L) muscles. Five weeks after recovery from surgery, isometric forces exerted at the distal tendons of FCU and PL were quantified at various FCU lengths. PL was kept at a constant length. Changing the muscle-tendon complex length of transferred FCU (by maximally 3.5 mm) decreased PL force significantly (by 7%). A linear relationship was found between changes in FCU muscle belly length, being a measure of muscle relative positions, and PL force. These results indicate that despite transfer of FCU muscle to the extensor side of the forearm, changing FCU length still affects force transmission of its, now, antagonistic PL muscle. We conclude that a transferred muscle may still be mechanically linked to its former synergistic muscles. PMID:23738260

  6. One-year results from cryopreserved mitral allograft transplantation into the tricuspid position in a sheep experimental model.

    PubMed

    Mokracek, A; Canadyova, J; Simunkova, Z; Fiala, R; Hmirak, M; Sulda, M; Burkert, J; Tintera, J; Kobylka, P; Spatenka, J

    2015-01-01

    Mitral allografts are still used only exceptionally in the mitral or tricuspid position. The main indication remains infectious endocarditis of atrioventricular valves for its flexibility and low risk of infection. The aim of our study was to evaluate 1-year results of mitral allografts transplantation into the tricuspid position in a sheep model. Mitral allografts were processed, cryopreserved, and transplanted into the tricuspid position anatomically (Group I - 11 animals) or antianatomically (Group II - 8 animals). All survivors (4 from Group I, and 3 from Group II) were checked at 3, 6, and 12 months by echocardiography with the exception of one survivor from Group II (which was examinated only visually). Examination throughout follow-up included for mitral allograft regurgitation and annuli dilatation. At postmortem, the papillary muscles were healed and firmly anchored to the right ventricular wall in all subjects. Transventricular fixation of the papillary muscles with buttressed sutures was proven to be a stable, reproducible, and safe method for anchoring mitral allograft leaflets. There were no significant differences between the two implantation methods. Annulus support of mitral allografts might be very useful in this type of operation and could prevent annular dilatation.

  7. Mucormycosis (zygomycosis) of renal allograft.

    PubMed

    Gupta, Krishan L; Joshi, Kusum; Kohli, Harbir S; Jha, Vivekanand; Sakhuja, Vinay

    2012-12-01

    Fungal infection is relatively common among renal transplant recipients from developing countries. Mucormycosis, also known as zygomycosis, is one of the most serious fungal infections in these patients. The most common of presentation is rhino-cerebral. Isolated involvement of a renal allograft is very rare. A thorough search of literature and our medical records yielded a total of 24 cases with mucormycosis of the transplanted kidney. There was an association with cytomegalovirus (CMV) infection and anti-rejection treatment in these patients and most of these transplants were performed in the developing countries from unrelated donors. The outcome was very poor with an early mortality in 13 (54.5%) patients. Renal allograft mucormycosis is a relatively rare and potentially fatal complication following renal transplantation. Early diagnosis, graft nephrectomy and appropriate antifungal therapy may result in an improved prognosis for these patients.

  8. Radioprotection of Tendon Tissue via Crosslinking and Free Radical Scavenging

    PubMed Central

    Seto, Aaron; Gatt, Charles J.

    2008-01-01

    Ionizing radiation could supplement tissue bank screening to further reduce the probability of diseases transmitted by allografts if denaturation effects can be minimized. It is important, however, such sterilization procedures be nondetrimental to tissues. We compared crosslinking and free radical scavenging potential methods to accomplish this task in tendon tissue. In addition, two forms of ionizing irradiation, gamma and electron beam (e-beam), were also compared. Crosslinkers included 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide (EDC) and glucose, which were used to add exogenous crosslinks to collagen. Free radical scavengers included mannitol, ascorbate, and riboflavin. Radioprotective effects were assessed through tensile testing and collagenase resistance testing after irradiation at 25 kGy and 50 kGy. Gamma and e-beam irradiation produced similar degenerative effects. Crosslinkers had the highest strength at 50 kGy, EDC treated tendons had 54% and 49% higher strength than untreated, for gamma and e-beam irradiation respectively. Free radical scavengers showed protective effects up to 25 kGy, especially for ascorbate and riboflavin. Crosslinked samples had higher resistance to collagenase and over a wider dose range than scavenger-treated. Of the options studied, the data suggest EDC precrosslinking or glucose treatment provides the best maintenance of native tendon properties after exposure to ionizing irradiation. PMID:18512113

  9. ENDOTHELIAL CELLS IN ALLOGRAFT REJECTION

    PubMed Central

    Al-Lamki, Rafia S.; Bradley, John R.; Pober, Jordan S.

    2008-01-01

    In organ transplantation, blood borne cells and macromolecules (e.g. antibodies) of the host immune system are brought into direct contact with the endothelial cell (EC) lining of graft vessels. In this location, graft ECs play several roles in allograft rejection, including the initiation of rejection responses by presentation of alloantigen to circulating T cells; the development of inflammation and thrombosis; and as targets of injury and agents of repair. PMID:19034000

  10. New Imaging Methods for Non-invasive Assessment of Mechanical, Structural, and Biochemical Properties of Human Achilles Tendon: A Mini Review

    PubMed Central

    Fouré, Alexandre

    2016-01-01

    The mechanical properties of tendon play a fundamental role to passively transmit forces from muscle to bone, withstand sudden stretches, and act as a mechanical buffer allowing the muscle to work more efficiently. The use of non-invasive imaging methods for the assessment of human tendon's mechanical, structural, and biochemical properties in vivo is relatively young in sports medicine, clinical practice, and basic science. Non-invasive assessment of the tendon properties may enhance the diagnosis of tendon injury and the characterization of recovery treatments. While ultrasonographic imaging is the most popular tool to assess the tendon's structural and indirectly, mechanical properties, ultrasonographic elastography, and ultra-high field magnetic resonance imaging (UHF MRI) have recently emerged as potentially powerful techniques to explore tendon tissues. This paper highlights some methodological cautions associated with conventional ultrasonography and perspectives for in vivo human Achilles tendon assessment using ultrasonographic elastography and UHF MRI. PMID:27512376

  11. New Imaging Methods for Non-invasive Assessment of Mechanical, Structural, and Biochemical Properties of Human Achilles Tendon: A Mini Review.

    PubMed

    Fouré, Alexandre

    2016-01-01

    The mechanical properties of tendon play a fundamental role to passively transmit forces from muscle to bone, withstand sudden stretches, and act as a mechanical buffer allowing the muscle to work more efficiently. The use of non-invasive imaging methods for the assessment of human tendon's mechanical, structural, and biochemical properties in vivo is relatively young in sports medicine, clinical practice, and basic science. Non-invasive assessment of the tendon properties may enhance the diagnosis of tendon injury and the characterization of recovery treatments. While ultrasonographic imaging is the most popular tool to assess the tendon's structural and indirectly, mechanical properties, ultrasonographic elastography, and ultra-high field magnetic resonance imaging (UHF MRI) have recently emerged as potentially powerful techniques to explore tendon tissues. This paper highlights some methodological cautions associated with conventional ultrasonography and perspectives for in vivo human Achilles tendon assessment using ultrasonographic elastography and UHF MRI. PMID:27512376

  12. Tendon elastic strain energy in the human ankle plantar-flexors and its role with increased running speed.

    PubMed

    Lai, Adrian; Schache, Anthony G; Lin, Yi-Chung; Pandy, Marcus G

    2014-09-01

    The human ankle plantar-flexors, the soleus and gastrocnemius, utilize tendon elastic strain energy to reduce muscle fiber work and optimize contractile conditions during running. However, studies to date have considered only slow to moderate running speeds up to 5 m s(-1). Little is known about how the human ankle plantar-flexors utilize tendon elastic strain energy as running speed is advanced towards maximum sprinting. We used data obtained from gait experiments in conjunction with musculoskeletal modeling and optimization techniques to calculate muscle-tendon unit (MTU) work, tendon elastic strain energy and muscle fiber work for the ankle plantar-flexors as participants ran at five discrete steady-state speeds ranging from jogging (~2 m s(-1)) to sprinting (≥8 m s(-1)). As running speed progressed from jogging to sprinting, the contribution of tendon elastic strain energy to the positive work generated by the MTU increased from 53% to 74% for the soleus and from 62% to 75% for the gastrocnemius. This increase was facilitated by greater muscle activation and the relatively isometric behavior of the soleus and gastrocnemius muscle fibers. Both of these characteristics enhanced tendon stretch and recoil, which contributed to the bulk of the change in MTU length. Our results suggest that as steady-state running speed is advanced towards maximum sprinting, the human ankle plantar-flexors continue to prioritize the storage and recovery of tendon elastic strain energy over muscle fiber work.

  13. An unusual array of extensor musculature and tendons of the hand clinico-anatomical insight.

    PubMed

    Dave, V; Gandhi, S; Mehta, V; Kumar, A; Arora, J; Suri, R K; Rath, G

    2014-01-01

    Extensor tendon injury is a frequent finding in clinical practice. During a routine dissection class of undergraduate medical students examining the extensor aspect of the right hand, they found an interesting pattern of extensor tendons. The extensor digitorum (ED) exhibited three tendons for the middle and ring fingers. The intermediate tendon of the ED was found to pass to the junctura connecting the tendons of the ring and middle fingers. Additionally the Extensor carpi ulnaris displayed two tendinus slips. The lateral slip was inserted on the base of fifth metacarpal as usual, whereas the medial slip divided into two strands- proximal and distal. Apart from the above findings in the current case specimen, there was an accessory muscle belly for the index finger and the extensor digiti minimi bifurcated into two tendinus slips which gained attachment to the dorsal digital expansion of the little finger. These accessory muscle bellies and tendons could possibly be utilized for tendon reconstructions such as repairs, tenoplasties or tendon transfers.

  14. Tendon Transfers for the Hypoplastic Thumb.

    PubMed

    Wall, Lindley B; Goldfarb, Charles A

    2016-08-01

    Thumb hypoplasia is a component of radial longitudinal deficiency. The severity of hypoplasia can range from a slightly smaller thumb to a complete absence. Types II and IIIA hypoplastic thumbs are candidates for reconstruction to improve function, stability, and strength. There are 2 commonly used tendon transfers that can augment thumb opposition strength: the Huber abductor digiti minimi muscle transfer and the flexor digitorum superficialis opposition transfer. Both transfers use ulnar-sided structures to augment the thenar musculature. The Huber opposition transfer increases thenar bulk, but does not provide additional tissue for metacarpophalangeal stability. PMID:27387085

  15. Endoscopic Management of Gluteus Medius Tendon Tears.

    PubMed

    Thaunat, Mathieu; Noël, Eric; Nové-Josserand, Laurent; Murphy, Colin G; Sbiyaa, Mouhcine; Sonnery-Cottet, Bertrand

    2016-03-01

    Tears in the gluteus medius and minimus tendons have been recognized as an important cause of recalcitrant greater trochanteric pain syndrome. Because of the frequency of partial-thickness undersurface tears, this relatively unknown pathology is often misdiagnosed and left untreated. Surgery is indicated in case of 4 associated conditions: (i) Failure of conservative treatment with duration of symptoms >6 months; (ii) magnetic resonance imaging showing a tendon tear; (iii) positive ultrasound-guided infiltration test; and (iv) the absence of an evolved fatty degeneration or atrophy of the gluteus medius and minimus muscle. Endoscopic repair of partial or full-thickness tears, with systematic resection of the bony structures implicated in the impingement, and a complete bursectomy appear to give satisfactory results, although these results remain to be confirmed by clinical studies with longer follow-up. The degree of tendon degeneration may compromise the tissue left for reattachment, raising concerns over its healing capacity, durability, and ultimate strength of the repair. PMID:26752773

  16. Rupture of the biceps tendon after arthroscopic thermal capsulorrhaphy.

    PubMed

    Hanypsiak, Bryan T; Faulks, Craig; Fine, Kenneth; Malin, Edward; Shaffer, Benjamin; Connell, Marc

    2004-07-01

    The use of thermal energy in the shoulder to tighten capsular tissues through collagen denaturation is well established. Although reported complication rates are low, the natural history of thermal manipulation to both target and collateral tissue is poorly defined. We report two cases of biceps tendon rupture after arthroscopic capsular shrinkage. Both patients were young, athletic men with normal long head biceps tendons at the time of surgery. Each patient experienced a complete tear of the long head with distal muscle retraction, resulting in a "Popeye" deformity, at 3 months postoperatively. One patient elected further surgery with biceps tenodesis. Both patients have returned to their athletic activities with minimal functional deficits.

  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. 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.

  19. Pentadecapeptide BPC 157 enhances the growth hormone receptor expression in tendon fibroblasts.

    PubMed

    Chang, Chung-Hsun; Tsai, Wen-Chung; Hsu, Ya-Hui; Pang, Jong-Hwei Su

    2014-01-01

    BPC 157, a pentadecapeptide derived from human gastric juice, has been demonstrated to promote the healing of different tissues, including skin, muscle, bone, ligament and tendon in many animal studies. However, the underlying mechanism has not been fully clarified. The present study aimed to explore the effect of BPC 157 on tendon fibroblasts isolated from Achilles tendon of male Sprague-Dawley rat. From the result of cDNA microarray analysis, growth hormone receptor was revealed as one of the most abundantly up-regulated genes in tendon fibroblasts by BPC 157. BPC 157 dose- and time-dependently increased the expression of growth hormone receptor in tendon fibroblasts at both the mRNA and protein levels as measured by RT/real-time PCR and Western blot, respectively. The addition of growth hormone to BPC 157-treated tendon fibroblasts dose- and time-dependently increased the cell proliferation as determined by MTT assay and PCNA expression by RT/real-time PCR. Janus kinase 2, the downstream signal pathway of growth hormone receptor, was activated time-dependently by stimulating the BPC 157-treated tendon fibroblasts with growth hormone. In conclusion, the BPC 157-induced increase of growth hormone receptor in tendon fibroblasts may potentiate the proliferation-promoting effect of growth hormone and contribute to the healing of tendon. PMID:25415472

  20. Diabetes alters mechanical properties and collagen fiber re-alignment in multiple mouse tendons.

    PubMed

    Connizzo, Brianne K; Bhatt, Pankti R; Liechty, Kenneth W; Soslowsky, Louis J

    2014-09-01

    Tendons function to transfer load from muscle to bone through their complex composition and hierarchical structure, consisting mainly of type I collagen. Recent evidence suggests that type II diabetes may cause alterations in collagen structure, such as irregular fibril morphology and density, which could play a role in the mechanical function of tendons. Using the db/db mouse model of type II diabetes, the diabetic skin was found to have impaired biomechanical properties when compared to the non-diabetic group. The purpose of this study was to assess the effect of diabetes on biomechanics, collagen fiber re-alignment, and biochemistry in three functionally different tendons (Achilles, supraspinatus, patellar) using the db/db mouse model. Results showed that cross-sectional area and stiffness, but not modulus, were significantly reduced in all three tendons. However, the tendon response to load (transition strain, collagen fiber re-alignment) occurred earlier in the mechanical test, contrary to expectations. In addition, the patellar tendon had an altered response to diabetes when compared to the other two tendons, with no changes in fiber re-alignment and decreased collagen content at the midsubstance of the tendon. Overall, type II diabetes alters tendon mechanical properties and the dynamic response to load.

  1. Slack length of gastrocnemius medialis and Achilles tendon occurs at different ankle angles.

    PubMed

    Hug, François; Lacourpaille, Lilian; Maïsetti, Olivier; Nordez, Antoine

    2013-09-27

    Although muscle-tendon slack length is a crucial parameter used in muscle models, this is one of the most difficult measures to estimate in vivo. The aim of this study was to determine the onset of the rise in tension (i.e., slack length) during passive stretching in both Achilles tendon and gastrocnemius medialis. Muscle and tendon shear elastic modulus was measured by elastography (supersonic shear imaging) during passive plantarflexion (0° and 90° of knee angle, 0° representing knee fully extended, in a random order) in 9 participants. The within-session repeatability of the determined slack length was good at 90° of knee flexion (SEM=3.3° and 2.2° for Achilles tendon and gastrocnemius medialis, respectively) and very good at 0° of knee flexion (SEM=1.9° and 1.9° for Achilles tendon and gastrocnemius medialis, respectively). The slack length of gastrocnemius medialis was obtained at a significantly lower plantarflexed angle than for Achilles tendon at both 0° (P<0.0001; mean difference=19.4±3.8°) and 90° of knee flexion (P<0.0001; mean difference=25.5±7.6°). In conclusion, this study showed that the joint angle at which the tendon falls slack can be experimentally determined using supersonic shear imaging. The slack length of gastrocnemius medialis and Achilles tendon occurred at different joint angles. Although reporting this result is crucial to a better understanding of muscle-tendon interactions, further experimental investigations are required to explain this result.

  2. Muscle strain injuries.

    PubMed

    Garrett, W E

    1996-01-01

    One of the most common injuries seen in the office of the practicing physician is the muscle strain. Until recently, little data were available on the basic science and clinical application of this basic science for the treatment and prevention of muscle strains. Studies in the last 10 years represent action taken on the direction of investigation into muscle strain injuries from the laboratory and clinical fronts. Findings from the laboratory indicate that certain muscles are susceptible to strain injury (muscles that cross multiple joints or have complex architecture). These muscles have a strain threshold for both passive and active injury. Strain injury is not the result of muscle contraction alone, rather, strains are the result of excessive stretch or stretch while the muscle is being activated. When the muscle tears, the damage is localized very near the muscle-tendon junction. After injury, the muscle is weaker and at risk for further injury. The force output of the muscle returns over the following days as the muscle undertakes a predictable progression toward tissue healing. Current imaging studies have been used clinically to document the site of injury to the muscle-tendon junction. The commonly injured muscles have been described and include the hamstring, the rectus femoris, gastrocnemius, and adductor longus muscles. Injuries inconsistent with involvement of a single muscle-tendon junction proved to be at tendinous origins rather than within the muscle belly. Important information has also been provided regarding injuries with poor prognosis, which are potentially repairable surgically, including injuries to the rectus femoris muscle, the hamstring origin, and the abdominal wall. Data important to the management of common muscle injuries have been published. The risks of reinjury have been documented. The early efficacy and potential for long-term risks of nonsteroidal antiinflammatory agents have been shown. New data can also be applied to the field

  3. [Damage to large tendons: Achilles, patellar and quadriceps tendons].

    PubMed

    Amlang, M H; Zwipp, H

    2006-07-01

    The etiology and mechanisms of Achilles, patellar and quadriceps tendon ruptures are very similar. Age dependent changes in tendon structure and disorders such gout, diabetes, rheumatic diseases and chronic renal failure are associated causes. The main mechanism of rupture is indirect trauma. Although clinical diagnosis is easy, ruptures are still frequently missed. Sonography is the main standard diagnostic tool. MRI is indicated only in special cases. Open operative repair is the most common treatment for quadriceps and patellar tendon ruptures. Treatment of Achilles tendon ruptures is moving towards an individualized choice of therapy. Percutaneous and other "minimally invasive" techniques will play an increasingly important role.

  4. Allografts in Soft Tissue Reconstructive Procedures

    PubMed Central

    Giedraitis, Andrius; Arnoczky, Steven P.; Bedi, Asheesh

    2014-01-01

    Context Allografts offer several important advantages over autografts in musculoskeletal reconstructive procedures, such as anterior cruciate ligament reconstruction. Despite growing widespread use of allograft tissue, serious concerns regarding safety and functionality remain. We discuss the latest knowledge of the potential benefits and risks of allograft use and offer a critical review of allograft tissue regulation, management, and sterilization to enable the surgeon to better inform athletes considering reconstructive surgery options. Evidence Acquisition A review of sources published in the past 10 years is the primary basis of this research. Study Design: Observational analysis (cohort study). Level of Evidence: Level 3. Results Comparable outcome data for autografts and allografts do not support universal standards for anterior cruciate ligament reconstruction, and physician recommendation and bias appear to significantly influence patient preference and satisfaction. Sterilization by gamma and electron-beam irradiation diminishes the biomechanical integrity of allograft tissue, but radioprotective agents such as collagen cross-linking and free radical scavengers appear to have potential in mitigating the deleterious effects of irradiation and preserving tissue strength and stability. Conclusion Allografts offer greater graft availability and reduced morbidity in orthopaedic reconstructive procedures, but greater expansion of their use by surgeons is challenged by the need to maintain tissue sterility and biomechanical functionality. Advances in the radioprotection of irradiated tissue may lessen concerns regarding allograft safety and structural stability. PMID:24790696

  5. Demand for human allograft tissue in Canada.

    PubMed

    Lakey, Jonathan R T; Mirbolooki, Mohammadreza; Rogers, Christina; Mohr, Jim

    2007-01-01

    There is relatively little known about the demand for allograft tissues in Canada. The Canadian Council for Donation and Transplantation (CCDT) is a national advisory body that undertook a comprehensive "market survey" to estimate surgical demand for human allograft tissues in Canada. The report "Demand for Human Allograft Tissue in Canada" reflects survey results sent to 5 prominent User Groups. User Groups were identified as orthopaedic surgeons; neurosurgeons; corneal transplant surgeons; plastic surgeons, specifically those at Canadian Burn Units; and cardiac surgeons (adult and paediatric surgery). The demand for allograft grafts was determined and then extrapolated across the total User Group and then increases in allograft tissue use over the next 1-2 years across User Groups were predicted. The overall response rate for the survey was 21.4%. It varied from a low of 19.6% for the orthopaedic survey to a high of 40.5% for the corneal survey. The estimated current demand for allograft tissue in Canada ranges from a low of 34,442 grafts per year to a high of 62,098 grafts per year. The predicted increase in use of allograft tissue over the next 1-2 year period would suggest that annual demand could rise to somewhere in the range of 42,589-72,210 grafts. The highest rated preferences (98% and 94%) were for accredited and Canadian tissue banks, respectively. This study represents a key step in addressing the paucity of information concerning the demand for allograft tissue in Canada.

  6. 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

  7. Evidence for a vertebrate catapult: elastic energy storage in the plantaris tendon during frog jumping.

    PubMed

    Astley, Henry C; Roberts, Thomas J

    2012-06-23

    Anuran jumping is one of the most powerful accelerations in vertebrate locomotion. Several species are hypothesized to use a catapult-like mechanism to store and rapidly release elastic energy, producing power outputs far beyond the capability of muscle. Most evidence for this mechanism comes from measurements of whole-body power output; the decoupling of joint motion and muscle shortening expected in a catapult-like mechanism has not been demonstrated. We used high-speed marker-based biplanar X-ray cinefluoroscopy to quantify plantaris muscle fascicle strain and ankle joint motion in frogs in order to test for two hallmarks of a catapult mechanism: (i) shortening of fascicles prior to joint movement (during tendon stretch), and (ii) rapid joint movement during the jump without rapid muscle-shortening (during tendon recoil). During all jumps, muscle fascicles shortened by an average of 7.8 per cent (54% of total strain) prior to joint movement, stretching the tendon. The subsequent period of initial joint movement and high joint angular acceleration occurred with minimal muscle fascicle length change, consistent with the recoil of the elastic tendon. These data support the plantaris longus tendon as a site of elastic energy storage during frog jumping, and demonstrate that catapult mechanisms may be employed even in sub-maximal jumps.

  8. Evidence for a vertebrate catapult: elastic energy storage in the plantaris tendon during frog jumping

    PubMed Central

    Astley, Henry C.; Roberts, Thomas J.

    2012-01-01

    Anuran jumping is one of the most powerful accelerations in vertebrate locomotion. Several species are hypothesized to use a catapult-like mechanism to store and rapidly release elastic energy, producing power outputs far beyond the capability of muscle. Most evidence for this mechanism comes from measurements of whole-body power output; the decoupling of joint motion and muscle shortening expected in a catapult-like mechanism has not been demonstrated. We used high-speed marker-based biplanar X-ray cinefluoroscopy to quantify plantaris muscle fascicle strain and ankle joint motion in frogs in order to test for two hallmarks of a catapult mechanism: (i) shortening of fascicles prior to joint movement (during tendon stretch), and (ii) rapid joint movement during the jump without rapid muscle-shortening (during tendon recoil). During all jumps, muscle fascicles shortened by an average of 7.8 per cent (54% of total strain) prior to joint movement, stretching the tendon. The subsequent period of initial joint movement and high joint angular acceleration occurred with minimal muscle fascicle length change, consistent with the recoil of the elastic tendon. These data support the plantaris longus tendon as a site of elastic energy storage during frog jumping, and demonstrate that catapult mechanisms may be employed even in sub-maximal jumps. PMID:22090204

  9. Peroneal tendons subluxation.

    PubMed

    Oliva, Francesco; Del Frate, Dario; Ferran, Nicholas Antonio; Maffulli, Nicola

    2009-06-01

    Subluxation of the peroneal tendons is uncommon. It occurs especially in skiing, soccer, basketball, rugby, ice skating, judo, sprint, water-skiing, mountaineering, and gymnastics. We present an overview of the injury, with the classification commonly used. Many surgical techniques have been described to manage recurrent subluxation of the peroneal tendons, but only Level IV/Grade C evidence has been produced. Thus, randomized controlled trials are necessary to determinate the best surgical management method. It appears that high-demand individuals should be primarily managed surgically, and retinaculoplasty seems to be, when indicated, the best surgical option: it affords less complications and a high rate of return to sports without reducing their activity levels.

  10. Role of tissue engineered collagen based tridimensional implant on the healing response of the experimentally induced large Achilles tendon defect model in rabbits: a long term study with high clinical relevance

    PubMed Central

    2013-01-01

    Background Tendon injury is one of the orthopedic conditions poses with a significant clinical challenge to both the surgeons and patients. The major limitations to manage these injuries are poor healing response and development of peritendinous adhesions in the injured area. This study investigated the effectiveness of a novel collagen implant on tendon healing in rabbits. Results Seventy five mature White New-Zealand rabbits were divided into treated (n = 55) and control (n = 20) groups. The left Achilles tendon was completely transected and 2 cm excised. The defects of the treated animals were filled with collagen implants and repaired with sutures, but in control rabbits the defects were sutured similarly but the gap was left untreated. Changes in the injured and normal contralateral tendons were assessed weekly by measuring the diameter, temperature and bioelectrical characteristics of the injured area. Clinical examination was done and scored. Among the treated animals, small pilot groups were euthanized at 5, 10, 15, 20, 30, 40 and 60 (n = 5 at each time interval) and the remainder (n = 20) and the control animals at 120 days post injury (DPI). The lesions of all animals were examined at macroscopic and microscopic levels and the dry matter content, water delivery and water uptake characteristics of the lesions and normal contralateral tendons of both groups were analyzed at 120 DPI. No sign of rejection was seen in the treated lesions. The collagen implant was invaded by the inflammatory cells at the inflammatory phase, followed by fibroplasia phase in which remnant of the collagen implant were still present while no inflammatory reaction could be seen in the lesions. However, the collagen implant was completely absorbed in the remodeling phase and the newly regenerated tendinous tissue filled the gap. Compared to the controls, the treated lesions showed improved tissue alignment and less peritendinous adhesion, muscle atrophy and fibrosis

  11. Isolated vastus lateralis tendon avulsion.

    PubMed

    Frank, Jonathan M; Riedel, Matthew D; McCormick, Frank M; Nho, Shane J

    2013-10-01

    Isolated avulsion of the vastus lateralis tendon is a very rare injury. To our knowledge, only 1 case has been reported in the literature. This tendon is crucial to knee stability and proper patellofemoral tracking. As isolated avulsion of the tendon tends to occur in young, active males, early surgical repair is recommended to allow them to maintain a high level of functional ability. We present the case of a 49-year-old man who sustained an isolated vastus lateralis tendon avulsion injury. The injury was successfully treated with suture anchor repair.

  12. Tribological characteristics of healthy tendon.

    PubMed

    Theobald, Peter S; Dowson, Duncan; Khan, Ilyas M; Jones, Michael D

    2012-07-26

    Tendons transfer muscular forces efficiently and painlessly, facilitating joint motion. Whilst the tribology of articular cartilage is constantly explored, a poorer understanding remains of tendon lubrication and friction. This study reports experimental data describing the tribological characteristics of tendon and its surrounding tissue, before presenting an arithmetic solution to facilitate numerical modelling. The experimental characteristics of the tensile (i.e. mid-substance) and compressive (i.e. fibrocartilaginous) regions of bovine flexor tendon were investigated using a pin-on-plate tribometer, with immunofluroscence analysis describing the relative intensity and distribution of surface-bound lubricin. Arithmetic analysis considering the digital extensor tendon determined that, in physiological conditions, the tensile tendon region was able to generate elastohydrodynamic lubrication (EHL). The equivalent region of compressive tendon exhibited a higher intensity of surface-bound lubricin which, it is hypothesised, serves to minimise the increased frictional resistance due to generating only mixed or boundary lubrication regimes. Arithmetic analysis indicates that, given a more favourable biomechanical environment, this region can also generate EHL. Whilst acknowledging the limitations of transferring data from an animal model to a clinical environment, by providing the first data and equations detailing the film thicknesses and lubrication regime for these two tendon regions it is hoped that clinicians, engineers and scientists can consider improved clinical strategies to tackle both tendinopathy and tendon rupture.

  13. Joint infection unique to hamstring tendon harvester used during anterior cruciate ligament reconstruction surgery.

    PubMed

    Tuman, Jeffrey; Diduch, David R; Baumfeld, Joshua A; Rubino, L Joseph; Hart, Joseph M

    2008-05-01

    Joint infection after anterior cruciate ligament (ACL) reconstruction is a rare but important clinical issue that must be resolved quickly to prevent secondary joint damage and preserve the graft. After careful analysis, we observed 3 infection cases within a 12-month period after ACL reconstruction, which represented an abnormally elevated risk. All reconstructions were performed by the same surgeon and used hamstring tendon allograft. For each surgery, the Target Tendon Harvester (DePuy Mitek, Raynham, MA) was used to harvest hamstring tendons. Through our review, we learned that this instrument was sterilized while assembled. It is our belief that ineffective sterilization of this hamstring graft harvester served as the origin for these infections. We have determined that appropriate sterilization technique involves disassembly of this particular hamstring tendon harvester before sterilization because of the tube-within-a-tube configuration. We have since continued to use the Target Tendon Harvester, disassembling it before sterilization. There have been no infections in the ensuing 12 months during which the surgeon performed over 40 primary ACL reconstructions via hamstring autograft. The information from this report is intended to provide arthroscopists with information about potential sources of infection after ACL reconstruction surgery. PMID:18442698

  14. Joint infection unique to hamstring tendon harvester used during anterior cruciate ligament reconstruction surgery.

    PubMed

    Tuman, Jeffrey; Diduch, David R; Baumfeld, Joshua A; Rubino, L Joseph; Hart, Joseph M

    2008-05-01

    Joint infection after anterior cruciate ligament (ACL) reconstruction is a rare but important clinical issue that must be resolved quickly to prevent secondary joint damage and preserve the graft. After careful analysis, we observed 3 infection cases within a 12-month period after ACL reconstruction, which represented an abnormally elevated risk. All reconstructions were performed by the same surgeon and used hamstring tendon allograft. For each surgery, the Target Tendon Harvester (DePuy Mitek, Raynham, MA) was used to harvest hamstring tendons. Through our review, we learned that this instrument was sterilized while assembled. It is our belief that ineffective sterilization of this hamstring graft harvester served as the origin for these infections. We have determined that appropriate sterilization technique involves disassembly of this particular hamstring tendon harvester before sterilization because of the tube-within-a-tube configuration. We have since continued to use the Target Tendon Harvester, disassembling it before sterilization. There have been no infections in the ensuing 12 months during which the surgeon performed over 40 primary ACL reconstructions via hamstring autograft. The information from this report is intended to provide arthroscopists with information about potential sources of infection after ACL reconstruction surgery.

  15. Nonoperative management of a partial patellar tendon rupture after bone-patellar tendon-bone graft harvest for ACL reconstruction.

    PubMed

    Benner, Rodney W; Shelbourne, K Donald; Freeman, Heather

    2013-12-01

    This is a case report of a young athlete who sustained a partial tear of the patellar tendon after anterior cruciate ligament (ACL) reconstruction with a bone-patellar tendon-bone (BPTB) autograft. The injury, diagnostic workup, and decision-making process that lead to the choice of nonsurgical treatment are described. Furthermore, the rehabilitation process is described in detail. The patient returned to his previous level of sports activity and had a good clinical outcome as measured by range of motion, isokinetic quadriceps muscle strength testing, single leg hop testing, and the modified Noyes survey. In the absence of extensor mechanism incompetence or radiographic evidence of significant patella alta, partial ruptures of the patella tendon after ACL reconstruction using a BPTB autograft may be treated nonoperatively.

  16. Right ventricular false tendons, a cadaveric approach.

    PubMed

    Loukas, Marios; Wartmann, Christopher T; Tubbs, R Shane; Apaydin, Nihal; Louis, Robert G; Black, Brandie; Jordan, Robert

    2008-06-01

    Left ventricular false tendons (LFTs) have been extensively described and recognized by gross anatomic studies. However, there is very little information available regarding right ventricular false tendons (RFTs). The aim of our study, therefore, was to explore and delineate the morphology, topography and morphometry of the RFTs, and provide a comprehensive picture of their anatomy across a broad range of specimens. We identified 35/100 heart specimens containing right ventricular RFTs and classified them into five types. In Type I (21, 47.7%) the RFTs, was located between the ventricular septum and the anterior papillary muscle; in Type II (11, 22.9%) between ventricular septum and the posterior papillary muscle; in Type III (7, 14.5%) between the anterior leaflet of the tricuspid valve and the right ventricular free wall; in Type IV (5, 10.4%) between the posterior papillary muscle and the ventricular free wall; and lastly, in Type V (4, 8.3%) between the anterior papillary muscle and ventricular free wall. The mean length of the RFTs was 18 +/- 7 mm with a mean diameter of 1.4 +/- 05 mm. Histologic examination with Masson trichrome and PAS revealed that 20 (41.6%) of the 48 RFTs carried conduction tissue fibers. The presence of conduction tissue fibers within the RFTs was limited to Types I, III, and IV. In Types II and V the RFTs resembled fibrous structures in contrast with Type I, II and IV, which were composed more of muscular fibers, including conduction tissue fibers. RFTs containing conduction tissue fibers were identified, which may implicate them in the appearance of arrhythmias.

  17. Allograft Anterior Cruciate Ligament Reconstruction in Patients Younger than 25 Years.

    PubMed

    Carter, Thomas R; Rabago, Michael T

    2016-05-01

    Purpose The purpose of this study was to evaluate the outcomes for patients younger than 25 years who had anterior cruciate ligament (ACL) reconstructions with allograft tissue. Methods A total of 52 ACL reconstructions performed with fresh-frozen, nonirradiated tibialis or Achilles allografts in active patients younger than 25 years. Outcome evaluations included the International Knee Documentation Committee (IKDC) objective and subjective forms, KT-1000 arthrometry and Lysholm. Results Forty-two patients were available for follow-up at an average follow-up of 65 months (range, 33-99 months). The average age at surgery was 17 years and 7 months (range, 11 years 10 months-24 years 8 months). Objective and subjective data were obtained from 37 patients with 1 requiring revision, and 5 patients had only subjective data. IKDC objective results were 29-A and 5-B. KT-1000 differences were 0 mm for 4 patients, 1 mm for 23, 2 mm for 8, 3 mm for 1, and > 5 mm for 1 patient. The average IKDC subjective score was 90.2 ± 15.0 and average Lysholm score was 90.0 ± 11. Conclusion The result of our study found that using nonirradiated Achilles or tibialis tendon allografts for ACL reconstructions in active patients younger than 25 years can achieve good outcomes, with a low rate of failure. PMID:26227787

  18. Allograft Anterior Cruciate Ligament Reconstruction in Patients Younger than 25 Years.

    PubMed

    Carter, Thomas R; Rabago, Michael T

    2016-05-01

    Purpose The purpose of this study was to evaluate the outcomes for patients younger than 25 years who had anterior cruciate ligament (ACL) reconstructions with allograft tissue. Methods A total of 52 ACL reconstructions performed with fresh-frozen, nonirradiated tibialis or Achilles allografts in active patients younger than 25 years. Outcome evaluations included the International Knee Documentation Committee (IKDC) objective and subjective forms, KT-1000 arthrometry and Lysholm. Results Forty-two patients were available for follow-up at an average follow-up of 65 months (range, 33-99 months). The average age at surgery was 17 years and 7 months (range, 11 years 10 months-24 years 8 months). Objective and subjective data were obtained from 37 patients with 1 requiring revision, and 5 patients had only subjective data. IKDC objective results were 29-A and 5-B. KT-1000 differences were 0 mm for 4 patients, 1 mm for 23, 2 mm for 8, 3 mm for 1, and > 5 mm for 1 patient. The average IKDC subjective score was 90.2 ± 15.0 and average Lysholm score was 90.0 ± 11. Conclusion The result of our study found that using nonirradiated Achilles or tibialis tendon allografts for ACL reconstructions in active patients younger than 25 years can achieve good outcomes, with a low rate of failure.

  19. New technical procedure involving Achilles tendon rupture treatment through transcutaneous suture.

    PubMed

    TarniŢă, DănuŢ Nicolae; TarniŢă, Daniela; Grecu, Dan Cristian; Calafeteanu, Dan Marian; Căpitănescu, Bogdan

    2016-01-01

    The Achilles tendon is the widest tendon of the human body. Achilles tendon belongs to the extrasynovial tendons group and this allows it a faster recovery, thanks to local hematoma from the peritenon, necessary for the scarification. We concluded that in Achilles tendon rupture treatment it is essential to maintain the tendon covering skin integrity, the peritendinous integrity, to maintain the local hematoma formed during and after tendon rupture, reattaching the ruptured tendon heads and maintain them in this position by suturing them and by relaxing the sural triceps muscle. The percutaneous suture requires five pairs of mirror micro-incisions (5 mm) on one side and the other of the tendon. It is necessary for one of the pairs to be placed to the rupture level. With a surgical needle, we arm the proximal and distal heads of the tendon by different threads. By traction and muscular relaxation, we bring in contact the two ruptured heads and then we knot together the arming threads. The inferior member was cast immobilized in relaxing position for the sural triceps muscle for a 45 days period. Using this technique, we have operated 15 cases in our Clinic. In all the cases, we obtained a healing by first intention of the tegument micro-incisions. After the cast immobilization suppression, during 30 days the patients were in a recovery program. At the end of this program, they have recovered completely the dorsal and plantar flexion and the walking. In four months after the surgery, the esthetic of the area is completely restored, this technique being the only surgical technique that realizes this recovery.

  20. Shear Loads Induce Cellular Damage in Tendon Fascicles

    PubMed Central

    Kondratko-Mittnacht, Jaclyn; Lakes, Roderic; Vanderby, Ray

    2016-01-01

    Tendon is vital to musculoskeletal function, transferring loads from muscle to bone for joint motion and stability. It is an anisotropic, highly organized, fibrous structure containing primarily type I collagen in addition to tenocytes and other extracellular matrix components contributing to maintenance and function. Tendon is generally loaded via normal stress in a longitudinal direction. However, certain situations, including fiber breakage, enzymatic remodeling, or tendon pathology may introduce various degrees of other loading modalities, such as shear-lag at the fiber level, potentially affecting cellular response and subsequent function. Fascicles from rat tail tendon were dissected and placed in one of three paired groups: intact, single laceration, or double laceration. Each pair had a mechanically tested and control specimen. Single laceration fascicles contained one transverse laceration to mimic a partial tear. Double laceration fascicles had overlapping, longitudinally separated lacerations on opposite sides to cause intra-fascicular shear transfer to be the primary mechanism of loading. Elastic properties of the fascicle, e.g. peak load, steady state load, and stiffness, decreased from intact to single laceration to double laceration groups. Surprisingly, 45% of the intact strength was maintained when shear was the primary internal load transfer mechanism. Cellular viability decreased after mechanical testing in both laceration groups; cell death appeared primarily in a longitudinal plane where high shear load transfer occurred. This cell death extended far from the injury site and may further compromise an already damaged tendon via enzymatic factors and subsequent remodeling associated with cell necrosis. PMID:26162546

  1. Shear loads induce cellular damage in tendon fascicles.

    PubMed

    Kondratko-Mittnacht, Jaclyn; Lakes, Roderic; Vanderby, Ray

    2015-09-18

    Tendon is vital to musculoskeletal function, transferring loads from muscle to bone for joint motion and stability. It is an anisotropic, highly organized, fibrous structure containing primarily type I collagen in addition to tenocytes and other extracellular matrix components contributing to maintenance and function. Tendon is generally loaded via normal stress in a longitudinal direction. However, certain situations, including fiber breakage, enzymatic remodeling, or tendon pathology may introduce various degrees of other loading modalities, such as shear-lag at the fiber level, potentially affecting cellular response and subsequent function. Fascicles from rat tail tendon were dissected and placed in one of three paired groups: intact, single laceration, or double laceration. Each pair had a mechanically tested and control specimen. Single laceration fascicles contained one transverse laceration to mimic a partial tear. Double laceration fascicles had overlapping, longitudinally separated lacerations on opposite sides to cause intra-fascicular shear transfer to be the primary mechanism of loading. Elastic properties of the fascicle, e.g. peak load, steady state load, and stiffness, decreased from intact to single laceration to double laceration groups. Surprisingly, 45% of the intact strength was maintained when shear was the primary internal load transfer mechanism. Cellular viability decreased after mechanical testing in both laceration groups; cell death appeared primarily in a longitudinal plane where high shear load transfer occurred. This cell death extended far from the injury site and may further compromise an already damaged tendon via enzymatic factors and subsequent remodeling associated with cell necrosis. PMID:26162546

  2. 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

  3. Radiation sterilization of skin allograft

    NASA Astrophysics Data System (ADS)

    Kairiyama, E.; Horak, C.; Spinosa, M.; Pachado, J.; Schwint, O.

    2009-07-01

    In the treatment of burns or accidental loss of skin, cadaveric skin allografts provide an alternative to temporarily cover a wounded area. The skin bank facility is indispensable for burn care. The first human skin bank was established in Argentina in 1989; later, 3 more banks were established. A careful donor selection is carried out according to the national regulation in order to prevent transmissible diseases. As cadaveric human skin is naturally highly contaminated, a final sterilization is necessary to reach a sterility assurance level (SAL) of 10 -6. The sterilization dose for 106 batches of processed human skin was determined on the basis of the Code of Practice for the Radiation Sterilization of Tissue Allografts: Requirements for Validation and Routine Control (2004) and ISO 11137-2 (2006). They ranged from 17.6 to 33.4 kGy for bioburdens of >10-162.700 CFU/100 cm 2. The presence of Gram negative bacteria was checked for each produced batch. From the analysis of the experimental results, it was observed that the bioburden range was very wide and consequently the estimated sterilization doses too. If this is the case, the determination of a tissue-specific dose per production batch is necessary to achieve a specified requirement of SAL. Otherwise if the dose of 25 kGy is preselected, a standardized method for substantiation of this dose should be done to confirm the radiation sterilization process.

  4. Middle phalanx skeletal morphology in the hand: can it predict flexor tendon size and attachments?

    PubMed

    Marzke, Mary W; Shrewsbury, Marvin M; Horner, Kristin E

    2007-10-01

    Specific sites on the palmar diaphysis of the manual middle phalanges provide attachment for the flexor digitorum superficialis (FDS) tendon. It has been assumed in the literature that lateral palmar fossae on these bones reflect locations for these attachments and offer evidence for relative size of the flexor tendon. This assumption has led to predictions about relative FDS muscle force potential from sizes of fossae on fossil hominin middle phalanges. Inferences about locomotor capabilities of fossil hominins in turn have been drawn from the predicted force potential of the flexor muscle. The study reported here provides a critical first step in evaluating hypotheses about behavioral implications of middle phalangeal morphology in fossil hominins, by testing the hypothesis that the lateral fossae reflect the size of the FDS tendon and the location of the terminal FDS tendon attachments on the middle phalanx. The middle phalangeal region was dissected in 43 individuals from 16 primate genera, including humans. Qualitative observations were made of tendon attachment locations relative to the lateral fossae. Length measurements of the fossae were tested as predictors of FDS tendon cross-sectional area and of FDS attachment tendon lengths. Our results lead to the conclusion that the hypothesis must be rejected, and that future attention should focus on functional implications of the palmar median bar associated with the lateral fossae.

  5. Spontaneous bilateral quadriceps tendon rupture.

    PubMed

    Vigneswaran, N; Lee, K; Yegappan, M

    2007-11-01

    Spontaneous bilateral quadriceps tendon ruptures are uncommon. We present a 30-year-old man with end-stage renal failure, who sustained this injury, and subsequently had surgical repair of both tendons on separate occasions. He has since regained full range of movement of both knees.

  6. Combined Reconstruction of the Medial Collateral Ligament and Anterior Cruciate Ligament Using Ipsilateral Quadriceps Tendon-Bone and Bone-Patellar Tendon-Bone Autografts.

    PubMed

    Hetsroni, Iftach; Mann, Gideon

    2016-06-01

    The exclusive autograft choice for medial collateral ligament (MCL) reconstruction that has been described until today is the semitendinosus tendon. However, this has some potential disadvantages in a knee with combined MCL-anterior cruciate ligament (ACL) injury, including weakening of the hamstring's anterior restraining action in an already ACL-injured knee and nonanatomic distal MCL graft insertion when leaving the semitendinosus insertion intact at the pes anserinus during reconstruction. Moreover, because some surgeons prefer to use the hamstring for autologous ACL reconstruction, the contralateral uninjured knee hamstring needs to be harvested as a graft source for the MCL reconstruction if autografts and not allografts are the surgeons' preference. We describe a technique for performing combined reconstruction of the MCL and ACL using ipsilateral quadriceps tendon-bone and bone-patellar tendon-bone autografts. This technique of MCL reconstruction spares the hamstring tendons and benefits from the advantage provided by bone-to-bone healing on the femur with distal and proximal MCL tibial fixation that closely reproduces the native MCL tibia insertion. PMID:27656381

  7. Combined Reconstruction of the Medial Collateral Ligament and Anterior Cruciate Ligament Using Ipsilateral Quadriceps Tendon-Bone and Bone-Patellar Tendon-Bone Autografts.

    PubMed

    Hetsroni, Iftach; Mann, Gideon

    2016-06-01

    The exclusive autograft choice for medial collateral ligament (MCL) reconstruction that has been described until today is the semitendinosus tendon. However, this has some potential disadvantages in a knee with combined MCL-anterior cruciate ligament (ACL) injury, including weakening of the hamstring's anterior restraining action in an already ACL-injured knee and nonanatomic distal MCL graft insertion when leaving the semitendinosus insertion intact at the pes anserinus during reconstruction. Moreover, because some surgeons prefer to use the hamstring for autologous ACL reconstruction, the contralateral uninjured knee hamstring needs to be harvested as a graft source for the MCL reconstruction if autografts and not allografts are the surgeons' preference. We describe a technique for performing combined reconstruction of the MCL and ACL using ipsilateral quadriceps tendon-bone and bone-patellar tendon-bone autografts. This technique of MCL reconstruction spares the hamstring tendons and benefits from the advantage provided by bone-to-bone healing on the femur with distal and proximal MCL tibial fixation that closely reproduces the native MCL tibia insertion.

  8. Effect of maturation and aging on material and ultrasonographic properties of equine superficial digital flexor tendon.

    PubMed

    Gillis, C; Sharkey, N; Stover, S M; Pool, R R; Meagher, D M; Willits, N

    1995-10-01

    Results of studies in human beings and other species have indicated that aging significantly influences the strength, modulus of elasticity, and energy storage ability of tendon. We wanted to determine the effects of aging on the material and ultrasonographic properties of equine superficial digital flexor (SDF) tendon. Ultrasonographic measurements of left forelimb SDF tendon cross-sectional area and mean echogenicity were made in 23 standing horses ranging in age from 2 to 23 years. All horses had not been in work for a minimum of 6 months prior to the study. After euthanasia, left forelimb bone-muscle-tendon-bone specimens were mounted in a materials testing system. The SDF tendon was cyclically loaded sinusoidally 100 times at 0.5 Hz from 1.5 to 5.0% strain, then was submitted to 10-minute creep-and-stress relaxation tests. Modulus of elasticity, load at 3% strain, and creep-and-stress relaxation were determined for each specimen. A significant positive correlation was found between elastic modulus and age. Correlation was not found between age and SDF tendon cross-sectional area or mean echogenicity. When 2-year-old horses were compared with older horses, the latter had tendons with a significantly (P = 0.007) greater modulus of elasticity. The authors conclude that increasing age through maturity is associated with a corresponding increase in equine SDF tendon elastic modulus.

  9. Future of allografts in sports medicine.

    PubMed

    Harner, Christopher D; Lo, Marvin Y

    2009-04-01

    Allografts play a prominent role in sports medicine, and their usage has increased dramatically over the past few decades, but the role of allograft in the future of sports medicine largely depends on several factors: (1) the ability of the tissue banking industry to convince both surgeons and the general population that tissue procurement is safe and nearly disease-free, (2) the ability to sterilize tissue with minimal compromise to tissue integrity, (3) successful clinical outcomes with allograft, and (4) the advent of artificial scaffolds and ligaments that function as well. PMID:19306738

  10. Allograft safety in anterior cruciate ligament reconstruction.

    PubMed

    Cohen, Steven B; Sekiya, Jon K

    2007-10-01

    Allograft tissue seems to provide an excellent option for reconstruction of the ACL in the primary and revision setting. Although in general the risks of using allograft tissue in ACL reconstruction are low, the consequences of complications associated with disease or infection transmission or of recurrent instability secondary to graft failure are large. Surgeons should provide patients with the information available regarding allograft risks and should have thorough knowledge of the source and preparation of the grafts by their tissue bank before implantation for ACL reconstruction.

  11. Allograft safety in anterior cruciate ligament reconstruction.

    PubMed

    Cohen, Steven B; Sekiya, Jon K

    2007-10-01

    Allograft tissue seems to provide an excellent option for reconstruction of the ACL in the primary and revision setting. Although in general the risks of using allograft tissue in ACL reconstruction are low, the consequences of complications associated with disease or infection transmission or of recurrent instability secondary to graft failure are large. Surgeons should provide patients with the information available regarding allograft risks and should have thorough knowledge of the source and preparation of the grafts by their tissue bank before implantation for ACL reconstruction. PMID:17920955

  12. Acromioclavicular joint reconstruction using a tendon graft: a biomechanical study comparing a novel “sutured throughout” tendon graft to a standard tendon graft

    PubMed Central

    Naziri, Qais; Williams, Nadine; Hayes, Westley; Kapadia, Bhaveen H.; Chatterjee, Dipal; Urban, William P.

    2016-01-01

    Background: With a recurrence rate of over 30%, techniques that offer stronger acromioclavicular (AC) joint reconstruction through increased graft strength may provide longevity. The purpose of our study was to determine the biomechanical strength of a novel tendon graft sutured throughout compared to a native tendon graft in Grade 3 anatomical AC joint reconstruction. Methods: For this in vitro experiment, nine paired (n = 18) embalmed cadaveric AC joints of three males and six females (age 86 years, range 51–94 years) were harvested. Anatomic repair with fresh bovine Achilles tendon grafts without bone block was simulated. Specimens were divided into two groups; with group 1 using grafts with ultra-high molecular-weight polyethylene (UHMWPE) suture ran throughout the entire length. In group 2, reconstruction with only native allografts was performed. The distal scapula and humerus were casted in epoxy compound and mounted on the mechanical testing machine. Tensile tests were performed using a mechanical testing machine at the rate of 50 mm/min. Maximum load and displacement to failure were collected. Results: The average load to failure was significantly higher for group 1 compared to group 2, with mean values of 437.5 N ± 160.7 N and 94.4 N ± 43.6 N, (p = 0.001). The average displacement to failure was not significantly different, with 29.7 mm ± 10.6 mm in group 1 and 25 mm ± 9.1 mm in group 2 (p = 0.25). Conclusion: We conclude that a UHMWPE suture reinforced graft can provide a 3.6 times stronger AC joint reconstruction compared to a native graft. PMID:27163106

  13. Relative Echogenicity of Tendons and Ligaments of the Palmar Metacarpal Region in Foals from Birth to 4 Months of Age: A Longitudinal Study.

    PubMed

    Spinella, Giuseppe; Britti, Domenico; Loprete, Giovanni; Musella, Vincenzo; Romagnoli, Noemi; Vilar, Jose M; Valentini, Simona

    2016-01-01

    The objective of this study was to evaluate relative echogenicity of superficial and deep digital flexor tendons, the accessory ligament of the deep digital flexor tendon and interosseous muscle of the metacarpal region in foals ages 1 week to 4 months; and assess the association between echogenicity and sex or side/laterality. Seven Standardbred trotter foals were examined. Right and left metacarpal regions (palmar surface) were ultrasonographically investigated, and four regions of interest were assessed. A significant increase in echogenicity was seen in superficial and deep digital flexor tendons, accessory ligament of deep digital flexor tendon, and interosseous muscle during growth from 1 week to 4 months of age. Echogenicity of examined tendons and ligaments was not influenced by gender nor laterality. Reference values for tendon and ligament echogenicity could function as a tool to discriminate between physiological and abnormal conditions such as congenital contractural conditions. PMID:27441630

  14. Relative Echogenicity of Tendons and Ligaments of the Palmar Metacarpal Region in Foals from Birth to 4 Months of Age: A Longitudinal Study

    PubMed Central

    Britti, Domenico; Loprete, Giovanni; Musella, Vincenzo; Romagnoli, Noemi; Vilar, Jose M.; Valentini, Simona

    2016-01-01

    The objective of this study was to evaluate relative echogenicity of superficial and deep digital flexor tendons, the accessory ligament of the deep digital flexor tendon and interosseous muscle of the metacarpal region in foals ages 1 week to 4 months; and assess the association between echogenicity and sex or side/laterality. Seven Standardbred trotter foals were examined. Right and left metacarpal regions (palmar surface) were ultrasonographically investigated, and four regions of interest were assessed. A significant increase in echogenicity was seen in superficial and deep digital flexor tendons, accessory ligament of deep digital flexor tendon, and interosseous muscle during growth from 1 week to 4 months of age. Echogenicity of examined tendons and ligaments was not influenced by gender nor laterality. Reference values for tendon and ligament echogenicity could function as a tool to discriminate between physiological and abnormal conditions such as congenital contractural conditions. PMID:27441630

  15. Two cases of peroneus brevis tendon tear.

    PubMed

    Minoyama, O; Uchiyama, E; Iwaso, H; Hiranuma, K; Takeda, Y

    2002-02-01

    A longitudinal tear of the peroneal tendon is thought to be the result of repetitive peroneal subluxation. However, this report documents two cases of longitudinal split of the peroneus brevis tendon that had no peroneal tendon subluxation. Primary suture was performed. Subluxation of the peroneal tendons was not identified surgically in either case.

  16. Osmotic pressure induced tensile forces in tendon collagen.

    PubMed

    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.

  17. 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.

  18. 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

  19. [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.

  20. Transphyseal anterior cruciate ligament reconstruction in a skeletally immature knee using anterior tibialis allograft.

    PubMed

    Cho, Yool; Jang, Soo-Jin; Son, Jung-Hwan

    2011-05-18

    Anterior cruciate ligament (ACL) injury in the skeletally immature individual is being recognized with increasing frequency. Nonoperative treatment of ACL injuries in skeletally immature patients have not been favorable. Surgical treatment options for complete ACL tears include primary ligament repair, extraarticular tenodesis, transphyseal reconstruction, partial transphyseal reconstruction, and physeal-sparing reconstruction. The advantage of transphyseal reconstruction is placement of the graft tissue in an isometric position, which provides better results, according to the literature. The potential disadvantage is angular or limb-length discrepancy caused by physeal violation. Controversy exists in allograft selection about whether bone or soft tissue passes into physes. The use of standard tunnels provides reliable results, but carries the risk of iatrogenic growth disturbance from physeal injury.This article presents 4 cases of transphyseal ACL reconstruction using anterior tibialis allograft in skeletally immature patients that had satisfactory functional outcomes with no growth disturbances. This is the first report of transphyseal ACL reconstruction using anterior tibialis allograft in skeletally immature patients in the English-speaking literature. All patients underwent transphyseal ACL reconstruction using anterior tibialis tendon allograft. None of the patients had angular deformities. No early physeal arrest was measured between the preoperative and postoperative radiographs. At last follow-up, the results of the Lachman test were normal for 3 patients and nearly normal for 1 patient. All patients demonstrated full range of knee motion (comparing the reconstructed knee to the contralateral knee). The results of the pivot-shift test were normal for 3 patients and nearly normal for 1 patient. No patients reported giving way.

  1. 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

  2. Radiation sterilization of tissue allografts: A review

    PubMed Central

    Singh, Rita; Singh, Durgeshwer; Singh, Antaryami

    2016-01-01

    Tissue substitutes are required in a number of clinical conditions for treatment of injured and diseased tissues. Tissues like bone, skin, amniotic membrane and soft tissues obtained from human donor can be used for repair or reconstruction of the injured part of the body. Allograft tissues from human donor provide an excellent alternative to autografts. However, major concern with the use of allografts is the risk of infectious disease transmission. Therefore, tissue allografts should be sterilized to make them safe for clinical use. Gamma radiation has several advantages and is the most suitable method for sterilization of biological tissues. This review summarizes the use of gamma irradiation technology as an effective method for sterilization of biological tissues and ensuring safety of tissue allografts. PMID:27158422

  3. Dynamometer Elbow Strength and Endurance Testing After Distal Biceps Reconstruction w/Allograft

    PubMed Central

    McGee, Alan; Strauss, Eric Jason; Jazrawi, Laith M.

    2015-01-01

    Objectives: The purpose of the current study is to investigate the functional strength outcomes of late distal biceps reconstruction using allograft tissue. Methods: Patients who underwent distal biceps reconstruction with allograft tissue between May 2007 and May 2013 were identified. Charts were retrospectively reviewed for post-operative complications, gross flexion and supination strength, and range of motion (ROM). Isokinetic strength and endurance in elbow flexion and forearm supination were measured in both arms. Tests were conducted using a dynamometer at 60o per second for isokinetic strength and 240o per second for endurance. Isometric strength testing was also measured for elbow flexion and forearm supination. Paired t tests were used for statistical analysis. Results: Ten patients with a mean age of 48 years (range 42 - 61 years) were included in the study. Distal biceps reconstruction was performed using an Achilles tendon allograft in 9 patients and a combination of tibialis anterior allograft and gracilis allograft in 1 patient. Of the reconstructions, 50% involved the dominant arm. Full ROM was observed in all patients at the time of their final follow up assessment. The mean follow-up for dynamometer strength testing was 34 months (range 13-81 months). No statistical differences were noted between data obtained from operative and contralateral extremities. The average peak torque of the operative limb (38.5± 5.9 Nm) was 91.7% of that of the contralateral limb (41.8±4.9 Nm) in flexion and 93.4% (operative, 5.7±1.3 Nm; contralateral, 6.1± 1.0 Nm) in supination. No significant differences were found in fatigue index between operative or contralateral limbs for flexion (operative, 34.1±17.1%; contralateral, 30.8±17.1%; p = 0.29) or supination (operative, 38.2±16.5%; contralateral, 42.1±11.9%; p = 0.65). . The only complication observed was a transient PIN palsy in one patient which resolved by 3 months post-operatively. All patients reported

  4. Computational Biology: Modeling Chronic Renal Allograft Injury.

    PubMed

    Stegall, Mark D; Borrows, Richard

    2015-01-01

    New approaches are needed to develop more effective interventions to prevent long-term rejection of organ allografts. Computational biology provides a powerful tool to assess the large amount of complex data that is generated in longitudinal studies in this area. This manuscript outlines how our two groups are using mathematical modeling to analyze predictors of graft loss using both clinical and experimental data and how we plan to expand this approach to investigate specific mechanisms of chronic renal allograft injury.

  5. Treatment of lymphocele in renal allograft recipients.

    PubMed

    Greenberg, B M; Perloff, L J; Grossman, R A; Naji, A; Barker, C F

    1985-04-01

    Retroperitoneal lymphoceles developed in 12 renal allograft recipients during the last nine years. The interval between transplantation and the development of symptoms averaged seven months. The specific syndrome suggesting the presence of a lymphocele included lower abdominal swelling, weight gain, and, occasionally, fever without an obvious source of infection. Although these symptoms mimicked allograft rejection, diagnosis was easily made by ultrasound and intravenous pyelogram. Surgical marsupialization of the lymphocele with drainage into the peritoneal cavity proved to be an effective treatment.

  6. Anatomic All-Inside Anterior Cruciate Ligament Reconstruction Using Quadriceps Tendon Autograft.

    PubMed

    Crall, Timothy S; Gilmer, Brian B

    2015-12-01

    All-inside anterior cruciate ligament reconstruction has recently gained popularity, in part because of its bone-sparing socket preparation and reported lower pain levels after surgery. However, because this technique uses suture loops and cortical suspension buttons for graft fixation, it has mostly been limited to looped graft constructs (e.g., hamstring autograft, peroneus longus allograft). Quadriceps tendon autograft offers several advantages in anterior cruciate ligament reconstruction but, until recently, has not been compatible with suture-loop and cortical suspensory fixation. We describe a technique that allows a relatively short (<75 mm) quadriceps tendon autograft (without bone block) to be used with established all-inside anatomic techniques. PMID:27284521

  7. General Overview and Summary of Concepts Regarding Tendon Disease Topics Addressed Related to Metabolic Disorders.

    PubMed

    Ackermann, Paul W; Hart, David A

    2016-01-01

    Painful and non-healing musculoskeletal disorders, eg. tendinopathy, pose a tremendous burden on society and the quality of life for patients. New advances in the understanding of connective tissue disorders such as tendinopathy reveal that common health problems such as obesity, atherosclerosis, hormonal dysfunctions and diabetes mellitus are closely linked to the metabolism of components of the musculoskeletal system, particularly tendons. As tendons function as multi-component "organ systems" (Muscle-TMJ-Tendon-Enthesis to Bone), tendons can be influenced directly, or indirectly via, for instance, alterations to muscle. However, this volume/set of chapters focus mainly on the tendon.Emerging findings in musculoskeletal research have established important new links in our understanding of tendon metabolism. Thereby, the function of the neuroendocrine/-immune axis, as well as supply of neuro-vascular factors, can be directly linked to the quality of tendon metabolism.Since some conditions, eg. atherosclerosis and diabetes mellitus, are more common in individuals as they age, and aging can also affect pain and tissue repair, convergence of such complications will potentially exert an increasingly significant impact on tendons as the demographics of many societies change with expanding percentages of the populations >60-65 years of age.Comorbidities related to metabolic dysfunction have to be identified early in patients with musculoskeletal disorders, such as acute tendon injuries or chronic tendinopathy, for therapeutic considerations regarding both operative and non-operative treatment protocols. Necessary interactions between researchers and clinicians with different subspecialties have to be initiated in order to optimize tissue metabolism for improved healing potentials. PMID:27535271

  8. Transplantation of cryopreserved canine venous allografts.

    PubMed

    Bank, H L; Schmehl, M K; Warner, R; Pratt, M F; Albernaz, M S; Metcalf, J S; Darcy, M

    1991-01-01

    Local vascular reconstructions frequently require the use of vein grafts to bridge arterial or venous defects. Most previous studies on the use of cryopreserved veins have used relatively large caliber vessels. There have been few studies on the effectiveness of cryopreserved micro- or small-venous allografts. Here, we tested two types of cryopreserved venous allografts: (1) 1.5- to 1.9-mm diameter microvenous grafts (MVG); and (2) 4- to 5-mm diameter small venous grafts (SVG). Cryopreserved MVG allografts were placed into saphenous arteries of six experimental dogs and SVG cryopreserved allografts were placed into femoral arteries of six experimental dogs for 3 to 6 weeks. Two fresh MVG autografts were also transplanted into experimental dogs as controls and autografts were transferred to the contralateral side in SVG dogs as controls. None of the six cryopreserved MVG grafts retained patency but three/six cryopreserved SVG allografts were patent at harvest. Histological examination of grfts revealed control autografts were undergoing arterialization with an intact intima. Experimental cryopreserved allografts showed extensive medial fibrosis, significant lymphocytic infiltrates, and sporadic areas of intact intima for both patent and nonpatent grafts.

  9. Invasive Streptococcus pyogenes after allograft implantation--Colorado, 2003.

    PubMed

    2003-12-01

    Allograft tissues are used for various orthopedic procedures (e.g., ligament reconstruction, meniscal transplantation, and spinal surgery). In 2002, approximately one million allografts were distributed for transplantation (American Association of Tissue Banks [AATB], unpublished data, 2002). Recent reports of allograft-associated infections have prompted evaluation of the processing and quality-control methods employed by tissue processors. This report describes a case of invasive disease with Streptococcus pyogenes (i.e., group A streptococcus [GAS]), after reconstructive knee surgery using contaminated allograft tissue and provides recommendations to reduce the risk for allograft-associated infections. Although allograft infections are rare, they highlight the need for improved tissue evaluation and processing standards.

  10. Biomechanical Evaluation of Human Allograft Compression in Anterior Cruciate Ligament Reconstruction

    PubMed Central

    Lord, Breck; Yasen, Sam; Amis, Andrew; Wilson, Adrian

    2016-01-01

    Introduction: A common problem encountered during ACL reconstruction is asymmetry of proximal-distal graft diameter leading to tunnel upsizing and potential graft-tunnel mismatch. Human allografts are often oedematous, compounding this issue in the context of multi-ligament reconstructions. Tunnel upsizing reduces bone stock, increases the complexity of multi-bundle surgery and may compromise graft-osseous integration if cortical suspensory fixation is used. Graft compression provides uniform size, allowing easy passage into a smaller tunnel, potentially improving the ‘press-fit’ graft-osseous interaction whilst preserving bone stock. To our knowledge, no biomechanical evaluation of this increasing popular technique has been reported. Hypotheses: Graft compression would not cause any significant changes in the biomechanical properties of human allograft tendon that would be detrimental to the function of an ACL reconstruction. Compressed Bioclense® allograft will increase in size when soaked in Ringer’s solution at 36° improving the ‘press-fit’ within the bone socket, decreasing micro-motion at the graft-osseous interface following ACL reconstruction. Method: In-vitro laboratory study. Sixteen samples of Bioclense® treated peroneus longus allograft were quadrupled into GraftLink constructs randomly divided into control and compressed groups. Cross-sectional area (CSA) was determined using alginate moulds and specimens immersed, under tension, in Ringer’s solution at 36.5°. CSA was measured at 8 hours. A further 32 samples were randomised and evaluated under cyclic loading of 70N-220N (1020 cycles) followed by test to failure. A further 30 samples were quadrupled into GraftLink constructs and mounted within porcine femurs using suspensory fixation. High resolution videometer recorded motion at the graft-osseous interface under the same cyclic loading protocol. An independent samples t-test was used to compare changes in CSA whilst a one-way ANOVA was

  11. A Systematic Review of Failed Anterior Cruciate Ligament Reconstruction With Autograft Compared With Allograft in Young Patients

    PubMed Central

    Wasserstein, David; Sheth, Ujash; Cabrera, Alison; Spindler, Kurt P.

    2015-01-01

    Context: The advantages of allograft anterior cruciate ligament reconstruction (ACLR), which include shorter surgical time, less postoperative pain, and no donor site morbidity, may be offset by a higher risk of failure. Previous systematic reviews have inconsistently shown a difference in failure prevalence by graft type; however, such reviews have never been stratified for younger or more active patients. Objective: To determine whether there is a different ACLR failure prevalence of autograft compared with allograft in young, active patients. Data Sources: EMBASE, MEDLINE, Cochrane trials registry. Study Selection: Comparative studies of allograft versus autograft primary ACL reconstruction in patients <25 years of age or of high-activity level (military, Marx activity score >12 points, collegiate or semiprofessional athletes). Study Design: Systematic review with meta-analysis. Level of Evidence: Level 3. Data Extraction: Manual extraction of available data from eligible studies. Quantitative synthesis of failure prevalence and Lysholm score (outcomes in ≥3 studies) and I2 test for heterogeneity. Assessment of study quality using CLEAR NPT and Newcastle-Ottawa Scale (NOS). Results: Seven studies met inclusion criteria (1 level 1; 2 level 2, 4 level 3), including 788 patients treated with autograft tissue and 228 with various allografts. The mean age across studies was 21.7 years (64% male), and follow-up ranged between 24 and 51 months. The pooled failure prevalence was 9.6% (76/788) for autografts and 25.0% (57/228) for allografts (relative risk, 0.36; 95% CI, 0.24-0.53; P < 0.00001; I2 = 16%). The number needed to benefit to prevent 1 failure by using autograft was 7 patients (95% CI, 5-10). No difference between hamstrings autograft and patella tendon autograft was noted. Lysholm score was reported in 3 studies and did not differ between autograft and allograft. Conclusion: While systematic reviews comparing allograft and autograft ACLR have been equivocal

  12. POSTERIOR CRUCIATE LIGAMENT RECONSTRUCTION WITH AUTOGRAFT OF THE DOUBLE SEMITENDINOSUS MUSCLES AND MIDDLE THIRD OF THE QUADRICEPS TENDON WITH DOUBLE FEMORAL AND SINGLE TIBIAL TUNNELS: CLINICAL RESULTS IN TWO YEARS FOLLOW UP

    PubMed Central

    Cury, Ricardo de Paula Leite; Severino, Nilson Roberto; Camargo, Osmar Pedro Arbix; Aihara, Tatsuo; de Oliveira, Victor Marques; Avakian, Roger

    2015-01-01

    Objective: To evaluate the surgical aspects that may offer good anatomic and functional results in posterior cruciate ligament (PCL) reconstruction using an autologous graft of the quadriceps tendon and double semitendinosus through a double femoral tunnel. Methods: Fourteen patients with isolated PCL lesions, instability and pain were operated on by arthroscopy and evaluated according to the International Knee Documentation Committee (IKDC) and Lysholm scales. Posterior knee laxity was examined with a KT1000 arthrometer. Results: The mean postoperative posterior side-to-side difference was between 0-2 mm in 57.1% of patients and between 3 and 5 mm in 35.7% of cases. The average Lysholm score was 93 points in the final follow-up. In the IKDC evaluation, 3 patients were graded A, 10 were graded B, and 1 patient was graded C. Conclusions: Double bundle arthroscopic PCL reconstruction based on the anatomical positioning of the tunnels, with double semitendinosus tendon and single quadriceps, provides a clinically evident reduction in symptoms and restores satisfactory stability, although no statistically significant difference was found due to the small sample. PMID:27027083

  13. Etiology and pathophysiology of tendon ruptures in sports.

    PubMed

    Kannus, P; Natri, A

    1997-04-01

    associated with sports activities (5). The rupture (avulsion) of the distal tendon of the biceps muscle is rare. In sports, gymnastics, body building and weight lifting have been said to be able to produce this injury (6). In general, complete ruptures of the quadriceps tendon and the patellar tendon occur most often in older individuals. In our study, the mean age of these patients was 65 years (5). However, these injuries do also occur in younger age groups, especially in athletes. In athletes, the rupture most frequently occurs in high-power sports events, such as high jump, basketball and weight lifting, at the age of 15-30 years. A chronic-patellar apicitis (jumper's knee) may predispose rupture of the tendon (7). As is the case with the rotator cuff complex, overuse inflammation and partial tears of the quadriceps and patellar tendons are one of the most characteristic athletic injuries. Complete spontaneous ruptures of other tendons in sports are rare, although the literature does provide case studies from almost every tendon the human body possesses (8-18).

  14. A new method of repair for quadriceps tendon ruptures. A case report.

    PubMed

    Maniscalco, P; Bertone, C; Rivera, F; Bocchi, L

    2000-09-01

    Rupture of the quadriceps tendon is an uncommon injury observed predominantly in subjects over 40 years old. Multiple surgical techniques have been employed to repair fresh and neglected ruptures; methods that make use of allograft and augmentation with tissues harvested from around the knee have been reported. We describe a case of surgical repair of a tendon-bone junction rupture in a 64-year-old patient by use of suture anchors to attach the tendon to bone and improve fixation of the soft tissue elements. Clinical diagnosis of rupture was confirmed radiographically and echographically. Surgical repair was performed within 24 hours of injury. Active movement of the knee started after 3 weeks and the patient was permitted to walk without weight-bearing with a knee cage. Three weeks later, he was permitted to walk with full weight-bearing unassisted by crutches; the knee cage was removed 6 weeks after surgery. At his most recent follow-up 24 months postoperative, quadriceps strength was equal to that of the controlateral knee and the patient has returned to sports and daily activities. The surgical method presented here provides a suture of the tendon ends without putting excess stress on the suture line during the period of early knee mobilization. Advantages over other techniques include reduced operative time, easy access to the implantation site, and better resistance of the suture material: the patient is thus able to initiate physical therapy earlier and more aggressively.

  15. Arthroscopic capsule reconstruction in the hip using iliotibial band allograft.

    PubMed

    Trindade, Christiano A C; Sawyer, Gregory A; Fukui, Kiyokazu; Briggs, Karen K; Philippon, Marc J

    2015-02-01

    The hip capsule has been identified as an important static stabilizer of the hip joint. Despite the intrinsic bony stability of the hip socket, the capsule plays a key role in hip stability, particularly at the extremes of motion, and the iliofemoral ligament is the most important stabilizer in extension and external rotation. Patients who do not undergo capsular closure or plication may continue to complain of hip pain and dysfunction postoperatively, likely because of microinstability or muscle invagination into the capsular defect, and high-resolution magnetic resonance imaging or magnetic resonance arthrography will identify the capsular defect. Seen primarily in the revision setting, capsular defects can cause recurrent stress at the chondrolabral junction. An attempt at secondary closure can be challenging because of capsular limb adherence to the surrounding soft tissues. Therefore reconstruction may be the only possible surgical solution for this problem. We describe our new surgical technique for arthroscopic hip capsular reconstruction using iliotibial band allograft.

  16. Arthroscopic capsule reconstruction in the hip using iliotibial band allograft.

    PubMed

    Trindade, Christiano A C; Sawyer, Gregory A; Fukui, Kiyokazu; Briggs, Karen K; Philippon, Marc J

    2015-02-01

    The hip capsule has been identified as an important static stabilizer of the hip joint. Despite the intrinsic bony stability of the hip socket, the capsule plays a key role in hip stability, particularly at the extremes of motion, and the iliofemoral ligament is the most important stabilizer in extension and external rotation. Patients who do not undergo capsular closure or plication may continue to complain of hip pain and dysfunction postoperatively, likely because of microinstability or muscle invagination into the capsular defect, and high-resolution magnetic resonance imaging or magnetic resonance arthrography will identify the capsular defect. Seen primarily in the revision setting, capsular defects can cause recurrent stress at the chondrolabral junction. An attempt at secondary closure can be challenging because of capsular limb adherence to the surrounding soft tissues. Therefore reconstruction may be the only possible surgical solution for this problem. We describe our new surgical technique for arthroscopic hip capsular reconstruction using iliotibial band allograft. PMID:25973378

  17. Nerve Allografts Supplemented with Schwann Cells Overexpressing GDNF

    PubMed Central

    Santosa, Katherine B.; Jesuraj, Nithya J.; Viader, Andreu; MacEwan, Matthew; Newton, Piyaraj; Hunter, Daniel A.; Mackinnon, Susan E.; Johnson, Philip J.

    2012-01-01

    Introduction We sought to determine if supplementation of acellular nerve allografts (ANAs) with Schwann Cells overexpressing GDNF (G-SCs) would enhance functional recovery following peripheral nerve injury. Methods SCs expanded in vitro were infected with a lentiviral vector to induce GDNF overexpression. Wild type-SCs (WT-SCs) and G-SCs were seeded into ANAs used to repair a 14mm nerve gap defect. Animals were harvested after 6 and 12 weeks for histomorphometric and muscle force analysis. Results At 6 weeks, histomorphometry revealed that ANAs supplemented with G-SCs promoted similar regeneration compared to the isograft at midgraft. However, G-SCs failed to promote regeneration into the distal stump. At 12 weeks, ANAs with G-SCs had lower maximum and specific force production compared to controls. Discussion The combined results suggest that consistent overexpression of GDNF by G-SCs trapped axons in the graft and prevented functional regeneration. PMID:23169341

  18. Arthroscopically Assisted Latissimus Dorsi Tendon Transfer in Beach-Chair Position

    PubMed Central

    Jermolajevas, Viktoras; Kordasiewicz, Bartlomiej

    2015-01-01

    Irreparable rotator cuff tears remain a surgical problem. The open technique of latissimus dorsi (LD) tendon transfer to “replace” the irreparable rotator cuff is already well known. The aim of this article is to present a modified arthroscopically assisted LD tendon transfer technique. This technique was adopted to operate on patients in the beach-chair position with several improvements in tendon harvesting and fixation. It can be divided into 6 steps, and only 1 step—LD muscle and tendon release—is performed open. The advantages of the arthroscopic procedure are sparing of the deltoid muscle, the possibility of repairing the subscapularis tendon, and the ability to visualize structures at risk while performing tendon harvesting (radial nerve) and passing into the subacromial space (axillary nerve). It is performed in a similar manner to standard rotator cuff surgery—the beach-chair position does not need any modification, and no sophisticated equipment for either the open or arthroscopic part of the procedure is necessary. Nevertheless, this is a challenging procedure and should only be attempted after training, as well as extensive practice. PMID:26759777

  19. Hyaluronic acid and tendon lesions

    PubMed Central

    Kaux, Jean-François; Samson, Antoine; Crielaard, Jean-Michel

    2015-01-01

    Summary Introduction recently, the viscoelastic properties of hyaluronic acid (HA) on liquid connective tissue have been proposed for the treatment of tendinopathies. Some fundamental studies show encouraging results on hyaluronic acid’s ability to promote tendon gliding and reduce adhesion as well as to improve tendon architectural organisation. Some observations also support its use in a clinical setting to improve pain and function. This literature review analyses studies relating to the use of hyaluronic acid in the treatment of tendinopathies. Methods this review was constructed using the Medline database via Pubmed, Scopus and Google Scholar. The key words hyaluronic acid, tendon and tendinopathy were used for the research. Results in total, 28 articles (in English and French) on the application of hyaluronic acid to tendons were selected for their relevance and scientific quality, including 13 for the in vitro part, 7 for the in vivo animal part and 8 for the human section. Conclusions preclinical studies demonstrate encouraging results: HA permits tendon gliding, reduces adhesions, creates better tendon architectural organisation and limits inflammation. These laboratory observations appear to be supported by limited but encouraging short-term clinical results on pain and function. However, controlled randomised studies are still needed. PMID:26958533

  20. Parsonage-Turner syndrome and a localised swelling around the extensor tendons of the hand: a clinical sign indicating increased risk of rupture of the tendon.

    PubMed

    Vedung, Torbjörn

    2012-10-01

    Two patients presented with intense pain in the shoulder followed by weakness and paralysis of muscles in the shoulder and arm, together with a peculiar swelling on the hand. The swelling seems to predispose to rupture of the extensor tendon. If this tumour is a regular finding in Parsonage-Turner syndrome, it may also help in making a definitive diagnosis.

  1. The tendon network of the fingers performs anatomical computation at a macroscopic scale.

    PubMed

    Valero-Cuevas, Francisco J; Yi, Jae-Woong; Brown, Daniel; McNamara, Robert V; Paul, Chandana; Lipson, Hood

    2007-06-01

    Current thinking attributes information processing for neuromuscular control exclusively to the nervous system. Our cadaveric experiments and computer simulations show, however, that the tendon network of the fingers performs logic computation to preferentially change torque production capabilities. How this tendon network propagates tension to enable manipulation has been debated since the time of Vesalius and DaVinci and remains an unanswered question. We systematically changed the proportion of tension to the tendons of the extensor digitorum versus the two dorsal interosseous muscles of two cadaver fingers and measured the tension delivered to the proximal and distal interphalangeal joints. We find that the distribution of input tensions in the tendon network itself regulates how tensions propagate to the finger joints, acting like the switching function of a logic gate that nonlinearly enables different torque production capabilities. Computer modeling reveals that the deformable structure of the tendon networks is responsible for this phenomenon; and that this switching behavior is an effective evolutionary solution permitting a rich repertoire of finger joint actuation not possible with simpler tendon paths. We conclude that the structural complexity of this tendon network, traditionally oversimplified or ignored, may in fact be critical to understanding brain-body coevolution and neuromuscular control. Moreover, this form of information processing at the macroscopic scale is a new instance of the emerging principle of nonneural "somatic logic" found to perform logic computation such as in cellular networks. PMID:17549909

  2. In-vitro tensile testing machine for vibration study of fresh rabbit Achilles tendon

    NASA Astrophysics Data System (ADS)

    Revel, Gian M.; Scalise, Alessandro; Scalise, Lorenzo; Pianosi, Antonella

    2001-10-01

    A lot of people, overall athletic one suffer from tendinitis or complete rupture of the Achilles tendon. This structure becomes inflamed and damaged mainly from a variety of mechanical forces and sometimes due to metabolic problems, such as diabetes or arthritis. Over the past three decades extensive studies have been performed on the structural and mechanical properties of Achilles tendon trying to explain the constitutive equations to describe and foresee tendon behavior. Among the various mechanical parameters, the vibrational behavior is also of interest. Several investigations are performed in order to study how the Achilles tendon vibrations influence the response of the muscle proprioception and human posture. The present article describes how in vitro tensile experiments can be performed, taking into account the need to simulate physiological condition of Achilles tendon and thus approaching some opened problems in the design of the experimental set-up. A new system for evaluating tendon vibrations by non contact techniques is proposed. Preliminary simple elongation tests are made extracting the main mechanical parameters: stress and strain at different fixed stretches, in order to characterize the tissue. Finally, a vibration study is made at each pretensioned tendon level evaluating the oscillating curves caused by a small hammer.

  3. Relationship between joint motion and flexor tendon force in the canine forelimb.

    PubMed

    Lieber, R L; Amiel, D; Kaufman, K R; Whitney, J; Gelberman, R H

    1996-11-01

    To increase in vivo tendon force and gliding after flexor tendon repair, a variety of modifications to the methods by which protective passive motion is administered have been advocated. To determine the relationship between the prime variables, wrist and digital position, muscle activation, and in vivo tendon force, a clinically relevant canine model was developed. Force was measured in the flexor tendon during several joint manipulation paradigms: single-finger flexion-extension with the wrist flexed (group 1F), single-finger flexion-extension with the wrist extended (group 1E), four-finger flexion-extension with the wrist flexed (group 4F), four-finger flexion-extension with the wrist extended (group 4E), and synergistic wrist and finger motion where wrist extension and finger flexion were performed simultaneously, followed by wrist flexion and finger extension (group SYN). In addition, tendon force was measured during electric stimulation of the proximal flexor muscle mass. Passive tendon force with the wrist extended (groups 1E and 4E) was two to three times greater than that measured with the wrist flexed, independent of the number of digits moved. With the wrist extended, peak tendon force reached 1,997 g +/- 194 g during single-digit manipulation (group 1E), compared to only 853 g +/- 104 g with the wrist flexed during the same maneuver (group 1F). Statistical comparison between means revealed that groups 1E and 4E were significantly different from groups 1F, 4F, and SYN (p < .005). There were no significant differences between groups 1E and 4E or between groups 1F, 4F, and SYN (p > .200). Active muscle force elicited by electrical stimulation and passive force varied dramatically as the wrist was flexed from full extension 3460 g +/- 766 g to full flexion 427 g +/- 239 g (p < .001). Simultaneously, passive tension decreased from 940 g +/- 143 g with wrist extended to 76 g +/- 37 g with the wrist flexed. These data indicate that wrist position has the

  4. Force estimation from ensembles of Golgi tendon organs

    NASA Astrophysics Data System (ADS)

    Mileusnic, M. P.; Loeb, G. E.

    2009-06-01

    Golgi tendon organs (GTOs) located in the skeletal muscles provide the central nervous system with information about muscle tension. The ensemble firing of all GTO receptors in the muscle has been hypothesized to represent a reliable measure of the whole muscle force but the precision and accuracy of that information are largely unknown because it is impossible to record activity simultaneously from all GTOs in a muscle. In this study, we combined a new mathematical model of force sampling and transduction in individual GTOs with various models of motor unit (MU) organization and recruitment simulating various normal, pathological and neural prosthetic conditions. Our study suggests that in the intact muscle the ensemble GTO activity accurately encodes force information according to a nonlinear, monotonic relationship that has its steepest slope for low force levels and tends to saturate at the highest force levels. The relationship between the aggregate GTO activity and whole muscle tension under some pathological conditions is similar to one seen in the intact muscle during rapidly modulated, phasic excitation of the motor pool (typical for many natural movements) but quite different when the muscle is activated slowly or held at a given force level. Substantial deviations were also observed during simulated functional electrical stimulation.

  5. Human patellar tendon moment arm length: measurement considerations and clinical implications for joint loading assessment.

    PubMed

    Tsaopoulos, Dimitrios E; Baltzopoulos, Vasilios; Maganaris, Constantinos N

    2006-08-01

    Detailed understanding of the knee joint loading requires the calculation of muscle and joint forces in different conditions. In these applications the patellar tendon moment arm length is essential for the accurate estimation of the tibiofemoral joint loading. In this article, different methods that have been used to determine the patellar tendon moment arm length under in vivo and in vitro conditions are reviewed. The limitations and advantages associated with each of the methods are evaluated together with their applications in the different loading conditions that the musculoskeletal system is subjected to. The three main measurement methods that this review considers are the geometric method, the tendon excursion method and the direct load method. A comparison of relevant quantitative results is presented to asses the impact of the errors of each method on the quantification of the patellar tendon moment arm and the implications for joint loading assessment in clinical applications.

  6. Achilles tendon vibration-induced changes in plantar flexor corticospinal excitability.

    PubMed

    Lapole, Thomas; Temesi, John; Gimenez, Philippe; Arnal, Pierrick J; Millet, Guillaume Y; Petitjean, Michel

    2015-02-01

    Daily Achilles tendon vibration has been shown to increase muscle force, likely via corticospinal neural adaptations. The aim of the present study was to determine the extent by which corticospinal excitability is influenced during direct Achilles tendon vibration. Motor-evoked potentials (MEPs) were elicited in the soleus (SOL), gastrocnemius medialis (GM) and tibialis anterior (TA) by transcranial magnetic stimulation of the motor cortical area of the leg with and without Achilles tendon vibration at various frequencies (50, 80 and 110 Hz). Contralateral homologues were also investigated. SOL and GM MEP amplitude significantly increased by 226 ± 188 and 66 ± 39%, respectively, during Achilles tendon vibration, without any difference between the tested frequencies. No MEP changes were reported for TA or contralateral homologues. Increased SOL and GM MEP amplitude suggests increased vibration-induced corticospinal excitability independent of vibration frequency.

  7. An Important Cause of Pes Planus: The Posterior Tibial Tendon Dysfunction

    PubMed Central

    Erol, Kemal; Karahan, Ali Yavuz; Kerimoğlu, Ülkü; Ordahan, Banu; Tekin, Levent; Şahin, Muhammed; Kaydok, Ercan

    2015-01-01

    Posterior tibial tendon dysfunction (PTTD) is an important cause of acquired pes planus that frequently observed in adults. Factors that play a role in the development of PTTD such as age-related tendon degeneration, inflammatory arthritis, hypertension, diabetes mellitus, obesity, peritendinous injections and more rarely acute traumatic rupture of the tendon. PTT is the primary dynamic stabilizer of medial arch of the foot. Plantar flexion and inversion of the foot occurs with contraction of tibialis posterior tendon, and arch of the foot becomes elaveted while midtarsal joints are locked and midfoot-hindfoot sets as rigid. Thus, during the walk gastrocnemius muscle works more efficiently. If the PTT does not work in the order, other foot ligaments and joint capsule would be increasingly weak and than pes planus occurs. We present a 10-year-old female patient diagnosed as PTTD and conservative treatment with review of the current literature. PMID:25918629

  8. An important cause of pes planus: the posterior tibial tendon dysfunction.

    PubMed

    Erol, Kemal; Karahan, Ali Yavuz; Kerimoğlu, Ülkü; Ordahan, Banu; Tekin, Levent; Şahin, Muhammed; Kaydok, Ercan

    2015-01-28

    Posterior tibial tendon dysfunction (PTTD) is an important cause of acquired pes planus that frequently observed in adults. Factors that play a role in the development of PTTD such as age-related tendon degeneration, inflammatory arthritis, hypertension, diabetes mellitus, obesity, peritendinous injections and more rarely acute traumatic rupture of the tendon. PTT is the primary dynamic stabilizer of medial arch of the foot. Plantar flexion and inversion of the foot occurs with contraction of tibialis posterior tendon, and arch of the foot becomes elaveted while midtarsal joints are locked and midfoot-hindfoot sets as rigid. Thus, during the walk gastrocnemius muscle works more efficiently. If the PTT does not work in the order, other foot ligaments and joint capsule would be increasingly weak and than pes planus occurs. We present a 10-year-old female patient diagnosed as PTTD and conservative treatment with review of the current literature. PMID:25918629

  9. Radionuclide surveillance of the allografted pancreas

    SciTech Connect

    George, E.A.; Salimi, Z.; Carney, K.; Castaneda, M.; Garvin, P.J.

    1988-04-01

    To determine the value of scintigraphy to detect posttransplantation complications of the allografted pancreas, we retrospectively reviewed 209 scintigrams obtained with /sup 99m/Tc-sulfur colloid (/sup 99m/Tc-SC) and /sup 99m/Tc-glucoheptonate (/sup 99m/Tc-GH). The scintigraphic studies were performed in 37 recipients of simultaneous renal and pancreatic allografts harvested from the same donor. /sup 99m/Tc-SC was used as an indicator of thrombotic vasculitis; pancreatic perfusion and blood-pool parameters were monitored with /sup 99m/Tc-GH. In 11 of the 37 recipients, scintigraphic abnormalities suggested posttransplantation infarction. Recurrent episodes of acute rejection of the pancreatic allograft, which always coincided with acute rejection of the renal allograft, were monitored in 24 recipients. Rejection-induced ischemic pancreatitis was suggested in 12 of the 24 recipients and persisted in 10 recipients for several weeks after improvement of renal allograft rejection. Pancreatic atrophy was suggested scintigraphically in 16 of the 24 recipients with recurrent episodes of rejection. Spontaneous pancreatic-duct obstruction and obstructive pancreatitis were associated with a scintigraphic pattern similar to that of rejection-induced ischemic pancreatitis. We concluded that the specific radionuclides used in this series are useful for the surveillance and assessment of posttransplantation pancreatic infarction, acute rejection, pancreatitis, and atrophy

  10. Transient mixed chimerism for allograft tolerance.

    PubMed

    Oura, Tetsu; Hotta, Kiyohiko; Cosimi, A B; Kawai, Tatsuo

    2015-04-01

    Mixed chimerism discovered in Freemartin cattle by Ray Owen 70 years ago paved the way for research on immune tolerance. Since his discovery, significant progress has been made in the effort to induce allograft tolerance via mixed chimerism in various murine models. However, induction of persistent mixed chimerism has proved to be extremely difficult in major histocompatibility complex mismatched humans. Chimerism induced in humans tends to either disappear or convert to full donor chimerism, depending on the intensity of the conditioning regimen. Nevertheless, our studies in both NHPs and humans have clearly demonstrated that renal allograft tolerance can be induced by transient mixed chimerism. Our studies have shown that solid organ allograft tolerance via transient mixed chimerism 1) requires induction of multilineage hematologic chimerism, 2) depends on peripheral regulatory mechanisms, rather than thymic deletion, for long-term maintenance, 3) is organ specific (kidney and lung but not heart allograft tolerance are feasible). A major advantage of tolerance induction via transient mixed chimerism is exclusion of the risk of graft-versus-host disease. Our ongoing studies are directed toward improving the consistency of tolerance induction, reducing the morbidity of the conditioning regimen, substituting clinically available agents, such as Belatacept for the now unavailable anti-CD2 monoclonal antibody, and extending the protocol to recipients of deceased donor allografts.

  11. Thrombotic microangiopathy in renal allografts

    PubMed Central

    Radha, S.; Tameem, Afroz; Sridhar, G.; Aiyangar, A.; Rajaram, K. G.; Prasad, R.; Kiran, K.

    2014-01-01

    Thrombotic microangiopathy (TMA) is a serious complication of renal transplantation. It is a morphological expression of various etiological factors. In a renal allograft, TMA can occur de novo or be a recurrent disease. The aim of this study was to analyze the etiological factors and observe the changing trends of TMA with respect to emerging new etiological factors. We evaluated 131 graft biopsies over a period of 2½ years (2010-2012). All the renal biopsies were formalin fixed, paraffin embedded. Twenty serial sections were studied. Stains routinely used were Hematoxylin and Eosin, Periodic Acid Schiff, Massons Trichrome and Silver Methenamine stains. C4d by immunohistochemical method was done on all graft biopsies. Incidence of TMA in our series was 9.1%. Out of the 12 cases, five were associated with calcineurin inhibitor toxicity, three were diagnosed as acute antibody-mediated rejection, and two were recurrent haemolytic uremic syndrome. One patient developed haemolytic uremic syndrome on treatment with sirolimus and one patient was cytomegalovirus positive on treatment with ganciclovir, developed haemolytic uremic syndrome during treatment course. This study describes a spectrum of etiological factors for thrombotic mciroangiopathy ranging from common cause like calcineurin inhibitor toxicity to rare cause like ganciclovir induced TMA. PMID:24574627

  12. Thrombotic microangiopathy in renal allografts.

    PubMed

    Radha, S; Tameem, Afroz; Sridhar, G; Aiyangar, A; Rajaram, K G; Prasad, R; Kiran, K

    2014-01-01

    Thrombotic microangiopathy (TMA) is a serious complication of renal transplantation. It is a morphological expression of various etiological factors. In a renal allograft, TMA can occur de novo or be a recurrent disease. The aim of this study was to analyze the etiological factors and observe the changing trends of TMA with respect to emerging new etiological factors. We evaluated 131 graft biopsies over a period of 2½ years (2010-2012). All the renal biopsies were formalin fixed, paraffin embedded. Twenty serial sections were studied. Stains routinely used were Hematoxylin and Eosin, Periodic Acid Schiff, Massons Trichrome and Silver Methenamine stains. C4d by immunohistochemical method was done on all graft biopsies. Incidence of TMA in our series was 9.1%. Out of the 12 cases, five were associated with calcineurin inhibitor toxicity, three were diagnosed as acute antibody-mediated rejection, and two were recurrent haemolytic uremic syndrome. One patient developed haemolytic uremic syndrome on treatment with sirolimus and one patient was cytomegalovirus positive on treatment with ganciclovir, developed haemolytic uremic syndrome during treatment course. This study describes a spectrum of etiological factors for thrombotic mciroangiopathy ranging from common cause like calcineurin inhibitor toxicity to rare cause like ganciclovir induced TMA.

  13. Structural and Ultrastructural Characteristics of Bone-Tendon Junction of the Calcaneal Tendon of Adult and Elderly Wistar Rats

    PubMed Central

    Cury, Diego Pulzatto; Dias, Fernando José; Miglino, Maria Angélica; Watanabe, Ii-sei

    2016-01-01

    Tendons are transition tissues that transfer the contractile forces generated by the muscles to the bones, allowing movement. The region where the tendon attaches to the bone is called bone-tendon junction or enthesis and may be classified as fibrous or fibrocartilaginous. This study aims to analyze the collagen fibers and the cells present in the bone-tendon junction using light microscopy and ultrastructural techniques as scanning electron microscopy and transmission electron microscopy. Forty male Wistar rats were used in the experiment, being 20 adult rats at 4 months-old and 20 elderly rats at 20 months-old. The hind limbs of the rats were removed, dissected and prepared to light microscopy, transmission electron microscopy and scanning electron microscopy. The aging process showed changes in the collagen fibrils, with a predominance of type III fibers in the elderly group, in addition to a decrease in the amount of the fibrocartilage cells, fewer and shorter cytoplasmic processes and a decreased synthetic capacity due to degradation of the organelles involved in synthesis. PMID:27078690

  14. Structural and Ultrastructural Characteristics of Bone-Tendon Junction of the Calcaneal Tendon of Adult and Elderly Wistar Rats.

    PubMed

    Cury, Diego Pulzatto; Dias, Fernando José; Miglino, Maria Angélica; Watanabe, Ii-sei

    2016-01-01

    Tendons are transition tissues that transfer the contractile forces generated by the muscles to the bones, allowing movement. The region where the tendon attaches to the bone is called bone-tendon junction or enthesis and may be classified as fibrous or fibrocartilaginous. This study aims to analyze the collagen fibers and the cells present in the bone-tendon junction using light microscopy and ultrastructural techniques as scanning electron microscopy and transmission electron microscopy. Forty male Wistar rats were used in the experiment, being 20 adult rats at 4 months-old and 20 elderly rats at 20 months-old. The hind limbs of the rats were removed, dissected and prepared to light microscopy, transmission electron microscopy and scanning electron microscopy. The aging process showed changes in the collagen fibrils, with a predominance of type III fibers in the elderly group, in addition to a decrease in the amount of the fibrocartilage cells, fewer and shorter cytoplasmic processes and a decreased synthetic capacity due to degradation of the organelles involved in synthesis. PMID:27078690

  15. Extensive Loss of Tibialis Anterior Tendon: Surgical Repair With Split Tendon Transfer of Tibialis Posterior Tendon: A Case Report.

    PubMed

    Miyazaki, Tsuyoshi; Uchida, Kenzo; Kokubo, Yasuo; Inukai, Tomoo; Sakamoto, Takumi; Yamagishi, Atsushi; Kitade, Makoto; Baba, Hisatoshi

    2016-01-01

    Extensive damage of the tibialis anterior tendon is rare and mainly caused by trauma. Surgical treatment of these injuries can become challenging owing to the limited availability of autogenous graft resources for reconstruction of the defect. In the present case report, we describe a large defect in the midfoot soft tissue after a traffic injury, which included complete loss of the tibialis anterior tendon. The tendon was reconstructed by split tendon transfer of the tibialis posterior tendon without sacrificing function, which was confirmed by the follow-up examination at 6 years after injury. We believe split tendon transfer of the tibialis posterior tendon can be one of the treatment options for patients with extensive disruption of the tibialis anterior tendon. PMID:26213163

  16. Dynamic creep and pre-conditioning of the Achilles tendon in-vivo.

    PubMed

    Hawkins, David; Lum, Corey; Gaydos, Diane; Dunning, Russell

    2009-12-11

    Warm-up exercises are often advocated prior to strenuous exercise, but the warm-up duration and effect on muscle-tendon behavior are not well defined. The gastrocnemius-Achilles tendon complexes of 18 subjects were studied to quantify the dynamic creep response of the Achilles tendon in-vivo and the warm-up dose required for the Achilles tendon to achieve steady-state behavior. A custom testing chamber was used to determine each subject's maximum voluntary contraction (MVC) during an isometric ankle plantar flexion effort. The subject's right knee and ankle were immobilized for one hour. Subjects then performed over seven minutes of cyclic isometric ankle plantar flexion efforts equal to 25-35% of their MVC at a frequency of 0.75 Hz. Ankle plantar flexion effort and images from dual ultrasound probes located over the gastrocnemius muscle-Achilles tendon and the calcaneus-Achilles tendon junction were acquired for eight seconds at the start of each sequential minute of the activity. Ultrasound images were analyzed to quantify the average relative Achilles tendon strain at 25% MVC force (epsilon(25%MVC)) for each minute. The epsilon(25%MVC) increased from 0.3% at the start of activity to 3.3% after seven minutes, giving a total dynamic creep of ~3.0%. The epsilon(25%MVC) increased by more than 0.56% per minute for the first five minutes and increased by less than 0.13% per minute thereafter. Therefore, following a period of inactivity, a low intensity warm-up lasting at least six minutes or producing 270 loading cycles is required for an Achilles tendon to reach a relatively steady-state behavior.

  17. The effects of test environment and cyclic stretching on the failure properties of human patellar tendons

    SciTech Connect

    Haut, R.C.; Powlison, A.C. )

    1990-07-01

    There is a need to document the mechanical properties of patellar tendon allografts used for reconstructive surgery of the damaged anterior cruciate ligament, especially the effects of irradiation sterilization. The purpose of this study was to investigate the influences of in vitro test environment and low-level cyclic stretching prior to failure tests on nonirradiated and irradiated human graft tissues. Bilateral patellar tendons were split and each half processed accordingly. Some graft tissues were stretched cyclically at 2.5 mm deformation before failure. Experiments were performed in a 37 degrees C saline bath or with tissues moistened with a drip of the same. The irradiated grafts relaxed less and generated less slack length in the drip environment than the nonirradiated controls. Cyclic stretching did not alter failure characteristics of either graft tissue. While no significant differences in the tensile responses or failure characteristics were noted for irradiated and nonirradiated grafts in the drip, in the bath environment the nonirradiated tissues had greater strength and modulus. This resulted in there being a significant difference between irradiated and nonirradiated tissue responses in a heated saline bath environment. These experimental results exemplify the need to control in vitro test environments in the evaluation of various sterilization and preservation protocols for soft tissue allografts.

  18. Achilles tendon rupture rehabilitation

    PubMed Central

    Kearney, R. S.; Parsons, N.; Underwood, M.; Costa, M. L.

    2015-01-01

    Objectives The evidence base to inform the management of Achilles tendon rupture is sparse. The objectives of this research were to establish what current practice is in the United Kingdom and explore clinicians’ views on proposed further research in this area. This study was registered with the ISRCTN (ISRCTN68273773) as part of a larger programme of research. Methods We report an online survey of current practice in the United Kingdom, approved by the British Orthopaedic Foot and Ankle Society and completed by 181 of its members. A total of ten of these respondents were invited for a subsequent one-to-one interview to explore clinician views on proposed further research in this area. Results The survey showed wide variations in practice, with patients being managed in plaster cast alone (13%), plaster cast followed by orthoses management (68%), and orthoses alone (19%). Within these categories, further variation existed regarding the individual rehabilitation facets, such as the length of time worn, the foot position within them and weight-bearing status. The subsequent interviews reflected this clinical uncertainty and the pressing need for definitive research. Conclusions The gap in evidence in this area has resulted in practice in the United Kingdom becoming varied and based on individual opinion. Future high-quality randomised trials on this subject are supported by the clinical community. Cite this article: Bone Joint Res 2015;4:65–9 PMID:25868938

  19. Effect of Finger Posture on the Tendon Force Distribution Within the Finger Extensor Mechanism

    PubMed Central

    Lee, Sang Wook; Chen, Hua; Towles, Joseph D.; Kamper, Derek G.

    2009-01-01

    Understanding the transformation of tendon forces into joint torques would greatly aid in the investigation of the complex temporal and spatial coordination of multiple muscles in finger movements. In this study, the effects of the finger posture on the tendon force transmission within the finger extensor apparatus were investigated. In five cadaver specimens, a constant force was applied sequentially to the two extrinsic extensor tendons in the index finger, extensor digitorum communis and extensor indicis proprius. The responses to this loading, i.e. fingertip force/moment and regional strains of the extensor apparatus, were measured and analyzed to estimate the tendon force transmission into the terminal and central slips of the extensor hood. Repeated measures analysis of variance revealed that the amount of tendon force transmitted to each tendon slip was significantly affected by finger posture, specifically by the interphalangeal (IP) joint angles (p < 0.01). Tendon force transmitted to each of the tendon slips was found to decrease with the IP flexion. The main effect of the metacarpophalangeal joint angle was not as consistent as the IP angle, but there was a strong interaction effect for which MCP flexion led to large decreases in the slip forces (> 30%) when the IP joints were extended. The ratio of terminal slip force: central slip force remained relatively constant across postures at approximately 1.7:1. Force dissipation into surrounding structures was found to be largely responsible for the observed force-posture relationship. Due to the significance of posture in the force transmission to the tendon slips, the impact of finger posture should be carefully considered when studying finger motor control or examining injury mechanisms in the extensor apparatus. PMID:19045521

  20. Effects of posterior tibial tendon augmented with biografts and calcaneal osteotomy in stage II adult-acquired flatfoot deformity.

    PubMed

    Lee, Daniel

    2009-02-01

    Adult-acquired flatfoot deformity (AAFD) is a well-known condition leading to flexible flatfoot deformity. However, only recently have the function and muscle strength for balancing opposing muscles been more appreciated in laboratory studies. With the advancements in collagen science in tendon structure, the rationale and concept of some of the most common procedures in tendon transfer have been challenged. The current availability of biograft technology has provided an alternative in augmentation procedures instead of sacrificing autologous tendons. This novel approach may offer a viable option in AAFD, delivering much-needed collagen in a degenerative tendon. These biografts have shown ease of use and tissue biocompatibility in many orthopaedic and plastic surgery procedures and may prove to be an adjunct in the surgical option for AAFD. PMID:19825747

  1. Effects of gamma irradiation on the biomechanical properties of peroneus tendons

    PubMed Central

    Aguila, Christopher M; Delcroix, Gaëtan J-R; Kaimrajh, David N; Milne, Edward L; Temple, H Thomas; Latta, Loren L

    2016-01-01

    Purpose This study was designed to investigate the biomechanical properties of nonirradiated (NI) and irradiated (IR) peroneus tendons to determine if they would be suitable allografts, in regards to biomechanical properties, for anterior cruciate ligament reconstruction after a dose of 1.5–2.5 Mrad. Methods Seven pairs of peroneus longus (PL) and ten pairs of peroneus brevis (PB) tendons were procured from human cadavers. The diameter of each allograft was measured. The left side of each allograft was IR at 1.5–2.5 Mrad, whereas the right side was kept aseptic and NI. The allografts were thawed, kept wet with saline, and attached in a single-strand fashion to custom freeze grips using liquid nitrogen. A preload of 10 N was then applied and, after it had reached steady state, the allografts were pulled at 4 cm/sec. The parameters recorded were the displacement and force. Results The elongation at the peak load was 10.3±2.3 mm for the PB NI side and 13.5±3.3 mm for the PB IR side. The elongation at the peak load was 17.4±5.3 mm for the PL NI side and 16.3±2.0 mm for the PL IR side. For PL, the ultimate load was 2,091.6±148.7 N for NI and 2,122.8±380.0 N for IR. The ultimate load for the PB tendons was 1,485.7±209.3 N for NI and 1,318.4±296.9 N for the IR group. The ultimate stress calculations for PL were 90.3±11.3 MPa for NI and 94.8±21.0 MPa for IR. For the PB, the ultimate stress was 82.4±19.0 MPa for NI and 72.5±16.6 MPa for the IR group. The structural stiffness was 216.1±59.0 N/mm for the NI PL and 195.7±51.4 N/mm for the IR side. None of these measures were significantly different between the NI and IR groups. The structural stiffness was 232.1±45.7 N/mm for the NI PB and 161.9±74.0 N/mm for the IR side, and this was the only statistically significant difference found in this study (P=0.034). Conclusion Our statistical comparisons found no significant differences in terms of elongation, ultimate load, or ultimate stress between IR and NI

  2. Effects of gamma irradiation on the biomechanical properties of peroneus tendons

    PubMed Central

    Aguila, Christopher M; Delcroix, Gaëtan J-R; Kaimrajh, David N; Milne, Edward L; Temple, H Thomas; Latta, Loren L

    2016-01-01

    Purpose This study was designed to investigate the biomechanical properties of nonirradiated (NI) and irradiated (IR) peroneus tendons to determine if they would be suitable allografts, in regards to biomechanical properties, for anterior cruciate ligament reconstruction after a dose of 1.5–2.5 Mrad. Methods Seven pairs of peroneus longus (PL) and ten pairs of peroneus brevis (PB) tendons were procured from human cadavers. The diameter of each allograft was measured. The left side of each allograft was IR at 1.5–2.5 Mrad, whereas the right side was kept aseptic and NI. The allografts were thawed, kept wet with saline, and attached in a single-strand fashion to custom freeze grips using liquid nitrogen. A preload of 10 N was then applied and, after it had reached steady state, the allografts were pulled at 4 cm/sec. The parameters recorded were the displacement and force. Results The elongation at the peak load was 10.3±2.3 mm for the PB NI side and 13.5±3.3 mm for the PB IR side. The elongation at the peak load was 17.4±5.3 mm for the PL NI side and 16.3±2.0 mm for the PL IR side. For PL, the ultimate load was 2,091.6±148.7 N for NI and 2,122.8±380.0 N for IR. The ultimate load for the PB tendons was 1,485.7±209.3 N for NI and 1,318.4±296.9 N for the IR group. The ultimate stress calculations for PL were 90.3±11.3 MPa for NI and 94.8±21.0 MPa for IR. For the PB, the ultimate stress was 82.4±19.0 MPa for NI and 72.5±16.6 MPa for the IR group. The structural stiffness was 216.1±59.0 N/mm for the NI PL and 195.7±51.4 N/mm for the IR side. None of these measures were significantly different between the NI and IR groups. The structural stiffness was 232.1±45.7 N/mm for the NI PB and 161.9±74.0 N/mm for the IR side, and this was the only statistically significant difference found in this study (P=0.034). Conclusion Our statistical comparisons found no significant differences in terms of elongation, ultimate load, or ultimate stress between IR and NI

  3. Bone graft substitute: allograft and xenograft.

    PubMed

    Shibuya, Naohiro; Jupiter, Daniel C

    2015-01-01

    Rapid bone graft incorporation for structural rigidity is essential. Early range of motion, exercise, and weight-bearing are keys to rehabilitation. Structural and nonstructural bone grafts add length, height, and volume to alter alignment, function, and appearance. Bone graft types include: corticocancellous autograft, allograft, xenograft, and synthetic graft. Autogenic grafts are harvested from the patient, less likely to be rejected, and more likely to be incorporated; however, harvesting adds a procedure and donor site complication is common. Allografts, xenografts, and synthetic grafts eliminate secondary procedures and donor site complications; however, rejection and slower incorporation can occur.

  4. Latissimus Dorsi Tendon Transfer for Irreparable Rotator Cuff Tears: A Modified Technique Using Arthroscopy

    PubMed Central

    Villacis, Diego; Merriman, Jarrad; Wong, Karlton; Rick Hatch, George F.

    2013-01-01

    Latissimus dorsi transfer is a well-established method for the treatment of posterosuperior massive irreparable rotator cuff tears. We propose using an arthroscopically assisted technique that avoids insult to the deltoid. With the patient in the lateral decubitus position, an L-shaped incision is made along the anterior belly of the latissimus muscle and then along the posterior axillary line. The latissimus and teres major are identified and separated. The tendon insertion of the latissimus is isolated, and a FiberWire traction suture (Arthrex, Naples, FL) is placed, facilitating dissection of the muscle to the thoracodorsal neurovascular pedicle and subsequent mobilization. The interval deep to the deltoid and superficial to the teres minor is developed into a subdeltoid tunnel for arthroscopic tendon transfer. The latissimus tendon is then transferred and stabilized arthroscopically to the lateral aspect of the infraspinatus and supraspinatus footprints by multiple suture anchors. PMID:23767006

  5. A long-term study of anterior cruciate ligament allograft reconstruction.

    PubMed

    Almqvist, K F; Willaert, Pieter; De Brabandere, S; Criel, K; Verdonk, R

    2009-07-01

    We retrospectively reviewed the long-term clinical outcome of unilateral arthroscopic anterior cruciate ligament (ACL) allograft reconstruction. From October 1995 to December 1997, 64 arthroscopic ACL reconstructions were performed. Multiligamentous knee injuries and ACL injuries in polytrauma patients were excluded and out of the remaining 60 patients 55 were available for follow-up. Three patients had suffered a rerupture caused by major trauma. One patient had a rerupture without significant trauma and one failure was caused by deep infection. These five patients were revised. Fifty patients (36 males, 14 females) were included in the final follow-up. At the time of evaluation, the mean duration of follow-up was 10 years and 6 months. All patients were examined by an independent examiner. Seven patients had an extension lag (<5 degrees) and all patients had a knee flexion of at least 120 degrees, with a mean flexion of 135 +/- 5 degrees compared to 135 +/- 8 degrees. At the time of follow-up, the median IKDC score was 97 (74-100). The Lysholm scoring scale had a median value of 95 (76-100). The median sports level on the Tegner scale was 6 (4-9). The one-leg-hop test showed a mean value of 95 +/- 5%. One patient did not perform the one-leg-hop test because of recent surgery to the Achilles tendon. In conclusion, the tibialis anterior or tibialis posterior tendon allograft ACL reconstruction produced good clinical results in the majority of patients at long-term follow-up.

  6. A long-term study of anterior cruciate ligament allograft reconstruction.

    PubMed

    Almqvist, K F; Willaert, Pieter; De Brabandere, S; Criel, K; Verdonk, R

    2009-07-01

    We retrospectively reviewed the long-term clinical outcome of unilateral arthroscopic anterior cruciate ligament (ACL) allograft reconstruction. From October 1995 to December 1997, 64 arthroscopic ACL reconstructions were performed. Multiligamentous knee injuries and ACL injuries in polytrauma patients were excluded and out of the remaining 60 patients 55 were available for follow-up. Three patients had suffered a rerupture caused by major trauma. One patient had a rerupture without significant trauma and one failure was caused by deep infection. These five patients were revised. Fifty patients (36 males, 14 females) were included in the final follow-up. At the time of evaluation, the mean duration of follow-up was 10 years and 6 months. All patients were examined by an independent examiner. Seven patients had an extension lag (<5 degrees) and all patients had a knee flexion of at least 120 degrees, with a mean flexion of 135 +/- 5 degrees compared to 135 +/- 8 degrees. At the time of follow-up, the median IKDC score was 97 (74-100). The Lysholm scoring scale had a median value of 95 (76-100). The median sports level on the Tegner scale was 6 (4-9). The one-leg-hop test showed a mean value of 95 +/- 5%. One patient did not perform the one-leg-hop test because of recent surgery to the Achilles tendon. In conclusion, the tibialis anterior or tibialis posterior tendon allograft ACL reconstruction produced good clinical results in the majority of patients at long-term follow-up. PMID:19421736

  7. Triceps tendon rupture in weight lifters.

    PubMed

    Sollender, J L; Rayan, G M; Barden, G A

    1998-01-01

    Triceps tendon avulsion injuries are rare. We report four weight lifters with triceps tendon raptures, two of whom had received local steroid injections for pain in the triceps. All four patients had taken oral anabolic steroids before injury. All patients had closed avulsion of the triceps tendon from its insertion into the olecranon. Three patients were injured while bench pressing heavy weights, and one patient was injured while swinging a baseball bat. Satisfactory results were achieved after surgical reinsertion of the tendon.

  8. [Percutaneous repair of achilles tendon rupture--a technical note].

    PubMed

    Alexa, O; Veliceasa, B; Puha, C; Popia, I

    2008-01-01

    The treatment of the acute ruptures of the achillean tendon remains controversial. For the time being, there is no consent regarding the ideal therapeutic approach. The therapeutical procedure for the recent achilean tendon tears varies between two possible solutions, one conservative and the other surgical. The choice between these is made based on the type of rupture and the experience of the surgeon. The conservative techniques can have good results in selected cases, but they produce a degree of elongation of the tendon, which may lead to improper functional results. The classical surgical treatment (the open technique) has the handicap of a relatively large, longitudinal incision, which is made in an area with relatively poor skin vascular supply. Also, the vascular supply of the tendon itself is based mainly on perforant, subfascial vessels, which are intercepted during the approach. Taking these facts into consideration, some new, minimally invasive (percutaneous) techniques, were imagined. The principles of the standard percutaneous technique consist of: 1) union of the ruptured ends without using a large surgical approach, thus also avoiding the drainage of the local hematoma and rushing the repair; 2) avoiding damaging of the tendon's vascular supply. This techique leads to a rapid transformation of the collagen fibers into elastic fibers, which are mechanically effective. We present in this paper the method which uses the TENOLIG kit. This kit consists of two wires with anchors at one end and needles at the other end; two washers and two poliethylene disks for securing the distal end of the wire. We obtained good morphological (proven by MRI scan) and functional results with this technique. The postoperative protocol includes immobilization with the foot initially in equinous, then in normal position, with isometric muscle contractions and non-weight-bearing, then removal of the cast and wires at 45 days postoperatively and continuing the recovery by

  9. A biomechanical assessment of superior shoulder translation after reconstruction of anterior glenoid bone defects: The Latarjet procedure versus allograft reconstruction

    PubMed Central

    Degen, Ryan M.; Giles, Joshua W.; Boons, Harm W.; Litchfield, Robert B.; Johnson, James A.; Athwal, George S.

    2013-01-01

    Background: The coracoacromial ligament (CAL) is an important restraint to superior shoulder translation. The effect of CAL release on superior stability following the Latarjet is unknown; therefore, our purpose was to compare the effect of two Latarjet techniques and allograft reconstruction on superior instability. Materials and Methods: Eight cadaveric specimens were tested on a simulator. Superior translation was monitored following an axial force in various glenohumeral rotations (neutral, internal, and external) with and without muscle loading. Three intact CAL states were tested (intact specimen, 30% glenoid bone defect, and allograft reconstruction) and two CAL deficient states (classic Latarjet (classicLAT) and congruent-arc Latarjet (congruentLAT)). Results: In neutral without muscle loading, a significant increase in superior translation occurred with the classicLAT as compared to 30% defect (P = 0.046) and allograft conditions (P = 0.041). With muscle loading, the classicLAT (P = 0.005, 0.002) and the congruentLAT (P = 0.018, 0.021) had significantly greater superior translation compared to intact and allograft, respectively. In internal rotation, only loaded tests produced significant results; specifically, classicLAT increased translation compared to all intact CAL states (P < 0.05). In external rotation, only unloaded tests produced significant results with classicLAT and congruentLAT allowing greater translations than intact (P ≤ 0.028). For all simulations, the allograft was not significantly different than intact (P > 0.05) and no differences (P = 1.0) were found between classicLAT and congruentLAT. Discussion: In most simulations, CAL release with the Latarjet lead to increased superior humeral translation. Conclusion: The choice of technique for glenoid bone loss reconstruction has implications on the magnitude of superior humeral translation. This previously unknown effect requires further study to determine its clinical and kinematic

  10. Free Flap Functional Muscle Transfers.

    PubMed

    Garcia, Ryan M; Ruch, David S

    2016-08-01

    Free functional muscle transfers remain a powerful reconstructive tool to restore upper extremity function when other options such as tendon or nerve transfers are not available. This reconstructive technique is commonly used for patients following trauma, ischemic contractures, and brachial plexopathies. Variable outcomes have been reported following free functional muscle transfers that are related to motor nerve availability and reinnervation. This article highlights considerations around donor motor nerve selection, dissection, and use of the gracilis muscle, and the surgical approach to performing a free functional muscle transfer to restore elbow flexion and/or digit flexion. PMID:27387083

  11. Effects of prolonged patellar tendon vibration on force steadiness in quadriceps femoris during force-matching task.

    PubMed

    Saito, Akira; Ando, Ryosuke; Akima, Hiroshi

    2016-01-01

    The quadriceps femoris (QF) muscle group plays an essential role in human movement, such as standing, walking and running. The ability to maintain a steady force during physical activity of the human lower limb is important for mobility, postural control and balance. Although prolonged mechanical vibration of the muscle-tendon unit can moderate the efficacy of synaptic input from Ia afferent onto the α-motor neuron pathway, the effect of prolonged tendon vibration on fluctuations of knee extensor force has received little attention. The purpose of the present study was to examine the effects of prolonged patellar tendon vibration on the force steadiness of the QF muscle. Nine healthy men performed a submaximal force-matching task involving isometric knee extension before and after patellar tendon vibration or quiet seated rest (n = 7, control condition) for 30 min. The target force was 2.5, 10 and 30 % of maximal voluntary contraction (MVC). Surface electromyography (EMG) of the four QF synergists was recorded and normalized to EMG amplitude during the MVC. The knee extension force and the EMG amplitude of vastus medialis during the MVC were significantly reduced after the vibration, but did not significantly decrease in the control condition. Fluctuations of force and normalized EMG of individual QF muscles at each submaximal force level did not significantly change after the vibration. We conclude that prolonged patellar tendon vibration does not influence the force steadiness of the QF muscle during an isometric force-matching task.

  12. Synthesis, development, characterization and effectiveness of bovine pure platelet gel-collagen-polydioxanone bioactive graft on tendon healing

    PubMed Central

    Moshiri, Ali; Oryan, Ahmad; Meimandi-Parizi, Abdolhamid

    2015-01-01

    Bovine platelet gel (BPG) is an accessible and cost-effective source of growth factors which may have a value in tendon regenerative medicine. We produced a collagen implant (CI) as a tendon proper, covered it with polydioxanone (PDS) sheath to simulate paratenon and finally embedded the BPG as an active source of growth factor within the bioimplant to test whether BPG would be able to accelerate and enhance tendon regeneration and repair. After in vitro characterization of the bioactive grafts, the grafts were implanted in rabbit large tendon defect model. Untreated tendons and tendons treated with either CI or CI-PDS were served as controls for the CI-PDS-BPG. The animals were investigated clinically, ultrasonographically and haematologically for 120 days. After euthanasia, dry matter content, water uptake and delivery characteristics and also gross morphological, histopathological and scanning electron microscopic features of the healing tendons were assessed. In vitro, the activated platelets in the scaffold, released their growth factors significantly more than the controls. BPG also increased cell viability, and enhanced cellular differentiation, maturation and proliferation inside the CI-PDS compared with the controls. In vivo, the BPG modulated inflammation, increased quality and rate of fibroplasia and produced a remodelled tendon that had significantly higher collagen content and superior collagen fibril and fibre differentiation than controls. Treatment also significantly improved tendon water uptake and delivery characteristics, animals’ serum PDGF level, CI-PDS biocompatibility and biodegradability and reduced peritendinous adhesions, muscle fibrosis and atrophy. BPG was effective on tendon healing and CI-PDS-BPG may be a valuable bioscaffold in tendon reconstructive surgery. PMID:25702535

  13. Synthesis, development, characterization and effectiveness of bovine pure platelet gel-collagen-polydioxanone bioactive graft on tendon healing.

    PubMed

    Moshiri, Ali; Oryan, Ahmad; Meimandi-Parizi, Abdolhamid

    2015-06-01

    Bovine platelet gel (BPG) is an accessible and cost-effective source of growth factors which may have a value in tendon regenerative medicine. We produced a collagen implant (CI) as a tendon proper, covered it with polydioxanone (PDS) sheath to simulate paratenon and finally embedded the BPG as an active source of growth factor within the bioimplant to test whether BPG would be able to accelerate and enhance tendon regeneration and repair. After in vitro characterization of the bioactive grafts, the grafts were implanted in rabbit large tendon defect model. Untreated tendons and tendons treated with either CI or CI-PDS were served as controls for the CI-PDS-BPG. The animals were investigated clinically, ultrasonographically and haematologically for 120 days. After euthanasia, dry matter content, water uptake and delivery characteristics and also gross morphological, histopathological and scanning electron microscopic features of the healing tendons were assessed. In vitro, the activated platelets in the scaffold, released their growth factors significantly more than the controls. BPG also increased cell viability, and enhanced cellular differentiation, maturation and proliferation inside the CI-PDS compared with the controls. In vivo, the BPG modulated inflammation, increased quality and rate of fibroplasia and produced a remodelled tendon that had significantly higher collagen content and superior collagen fibril and fibre differentiation than controls. Treatment also significantly improved tendon water uptake and delivery characteristics, animals' serum PDGF level, CI-PDS biocompatibility and biodegradability and reduced peritendinous adhesions, muscle fibrosis and atrophy. BPG was effective on tendon healing and CI-PDS-BPG may be a valuable bioscaffold in tendon reconstructive surgery.

  14. Effects of resistance training on tendon mechanical properties and rapid force production in prepubertal children

    PubMed Central

    Waugh, C. M.; Korff, T.; Fath, F.

    2014-01-01

    Children develop lower levels of muscle force, and at slower rates, than adults. Although strength training in children is expected to reduce this differential, a synchronous adaptation in the tendon must be achieved to ensure forces continue to be transmitted to the skeleton with efficiency while minimizing the risk of strain-related tendon injury. We hypothesized that resistance training (RT) would alter tendon mechanical properties in children concomitantly with changes in force production characteristics. Twenty prepubertal children (age 8.9 ± 0.3 yr) were equally divided into control (nontraining) and experimental (training) groups. The training group completed a 10-wk RT intervention consisting of 2–3 sets of 8–15 plantar flexion contractions performed twice weekly on a recumbent calf-raise machine. Achilles tendon properties (cross-sectional area, elongation, stress, strain, stiffness, and Young's modulus), electromechanical delay (EMD; time between the onset of muscle activity and force), rate of force development (RFD; slope of the force-time curve), and rate of electromyographic (EMG) increase (REI; slope of the EMG time curve) were measured before and after RT. Tendon stiffness and Young's modulus increased significantly after RT in the experimental group only (∼29% and ∼25%, respectively); all other tendon properties were not significantly altered, although there were mean decreases in both peak tendon strain and strain at a given force level (14% and 24%, respectively; not significant) which may have implications for tendon injury risk and muscle fiber mechanics. A decrease of ∼13% in EMD was found after RT for the experimental group, which paralleled the increase in tendon stiffness (r = −0.59); however, RFD and REI were unchanged. The present data show that the Achilles tendon adapts to RT in prepubertal children and is paralleled by a change in EMD, although the magnitude of this change did not appear to be sufficient to influence RFD

  15. Staged tendon grafts and soft tissue coverage

    PubMed Central

    Elliot, David

    2011-01-01

    The objective of the two-staged flexor tendon method is to improve the predictability of final results in difficult problems dealing with tendon reconstruction. This article reviews the evolution and benefits of this procedure. It also considers the use of the technique to help deal with problems requiring pulley and skin reconstruction simultaneously with re-constituting the flexor tendon system. PMID:22022043

  16. Allograft rejection in cattle with bovine leukocyte adhesion deficiency.

    PubMed

    Müller, K E; Rutten, V P; Becker, C K; Hoek, A; Bernadina, W E; Wentink, G H; Figdor, C G

    1995-09-01

    In the present investigation cell-mediated immunity in animals with bovine leukocyte adhesion deficiency (BLAD) was studied by means of skin transplantation experiments. Autograft and allograft behaviour in animals with BLAD was compared with the behaviour of simultaneously transplanted autografts and allografts in healthy controls. Allograft survival time was prolonged in three BLAD cattle (28, 30, and 72 days) compared to six healthy controls (12-14 days). When transplantations were repeated on one animal with BLAD using skin grafts from the same donor, accelerated rejection was observed (allograft survival time decreased from 72 days at primary to 35 days at secondary and to 21 days at tertiary transplantation), suggesting the development of immunological memory. Graft-infiltrating lymphocytes that were obtained from allograft biopsies during the period of rejection, were shown to be from recipient origin (beta 2-integrin negative). Our findings demonstrate that, although prolonged allograft survival is observed in cattle with BLAD, skin allografts are ultimately rejected. PMID:8533316

  17. Implantation of a Novel Biologic and Hybridized Tissue Engineered Bioimplant in Large Tendon Defect: An In Vivo Investigation

    PubMed Central

    Oryan, Ahmad; Moshiri, Ali; Parizi, Abdolhamid Meimandi

    2014-01-01

    Surgical reconstruction of large Achilles tendon defects is technically demanding. There is no standard method, and tissue engineering may be a valuable option. We investigated the effects of 3D collagen and collagen-polydioxanone sheath (PDS) implants on a large tendon defect model in rabbits. Ninety rabbits were divided into three groups: control, collagen, and collagen-PDS. In all groups, 2 cm of the left Achilles tendon were excised and discarded. A modified Kessler suture was applied to all injured tendons to retain the gap length. The control group received no graft, the treated groups were repaired using the collagen only or the collagen-PDS prostheses. The bioelectrical characteristics of the injured areas were measured at weekly intervals. The animals were euthanized at 60 days after the procedure. Gross, histopathological and ultrastructural morphology and biophysical characteristics of the injured and intact tendons were investigated. Another 90 pilot animals were also used to investigate the inflammatory response and mechanism of graft incorporation during tendon healing. The control tendons showed severe hyperemia and peritendinous adhesion, and the gastrocnemius muscle of the control animals showed severe atrophy and fibrosis, with a loose areolar connective tissue filling the injured area. The tendons receiving either collagen or collagen-PDS implants showed lower amounts of peritendinous adhesion, hyperemia and muscle atrophy, and a dense tendon filled the defect area. Compared to the control tendons, application of collagen and collagen-PDS implants significantly improved water uptake, water delivery, direct transitional electrical current and tissue resistance to direct transitional electrical current. Compared to the control tendons, both prostheses showed significantly increased diameter, density and alignment of the collagen fibrils and maturity of the tenoblasts at ultrastructure level. Both prostheses influenced favorably tendon healing

  18. Implantation of a novel biologic and hybridized tissue engineered bioimplant in large tendon defect: an in vivo investigation.

    PubMed

    Oryan, Ahmad; Moshiri, Ali; Parizi, Abdolhamid Meimandi; Maffulli, Nicola

    2014-02-01

    Surgical reconstruction of large Achilles tendon defects is technically demanding. There is no standard method, and tissue engineering may be a valuable option. We investigated the effects of 3D collagen and collagen-polydioxanone sheath (PDS) implants on a large tendon defect model in rabbits. Ninety rabbits were divided into three groups: control, collagen, and collagen-PDS. In all groups, 2 cm of the left Achilles tendon were excised and discarded. A modified Kessler suture was applied to all injured tendons to retain the gap length. The control group received no graft, the treated groups were repaired using the collagen only or the collagen-PDS prostheses. The bioelectrical characteristics of the injured areas were measured at weekly intervals. The animals were euthanized at 60 days after the procedure. Gross, histopathological and ultrastructural morphology and biophysical characteristics of the injured and intact tendons were investigated. Another 90 pilot animals were also used to investigate the inflammatory response and mechanism of graft incorporation during tendon healing. The control tendons showed severe hyperemia and peritendinous adhesion, and the gastrocnemius muscle of the control animals showed severe atrophy and fibrosis, with a loose areolar connective tissue filling the injured area. The tendons receiving either collagen or collagen-PDS implants showed lower amounts of peritendinous adhesion, hyperemia and muscle atrophy, and a dense tendon filled the defect area. Compared to the control tendons, application of collagen and collagen-PDS implants significantly improved water uptake, water delivery, direct transitional electrical current and tissue resistance to direct transitional electrical current. Compared to the control tendons, both prostheses showed significantly increased diameter, density and alignment of the collagen fibrils and maturity of the tenoblasts at ultrastructure level. Both prostheses influenced favorably tendon healing

  19. 38 CFR 4.56 - Evaluation of muscle disabilities.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 38 Pensions, Bonuses, and Veterans' Relief 1 2012-07-01 2012-07-01 false Evaluation of muscle... FOR RATING DISABILITIES Disability Ratings The Musculoskeletal System § 4.56 Evaluation of muscle disabilities. (a) An open comminuted fracture with muscle or tendon damage will be rated as a severe injury...

  20. Weave pattern of accessory heads to the anterior digastric muscle.

    PubMed

    Harvey, Jamison A; Call, Zach; Peterson, Katrina; Wisco, Jonathan J

    2015-10-01

    During routine anatomical dissection, we discovered bilateral superficial and deep heads of the anterior belly of the digastric muscle with concomitant accessory heads arranged in a weave pattern in the submental triangle. In addition, the left stylohyoid muscle coursed deep into the intermediate tendon of the digastric muscle bellies. PMID:25501489

  1. Achilles tendon mechanical properties after both prolonged continuous running and prolonged intermittent shuttle running in cricket batting.

    PubMed

    Houghton, Laurence; Dawson, Brian; Rubenson, Jonas

    2013-08-01

    Effects of prolonged running on Achilles tendon properties were assessed after a 60 min treadmill run and 140 min intermittent shuttle running (simulated cricket batting innings). Before and after exercise, 11 participants performed ramp-up plantar flexions to maximum-voluntary-contraction before gradual relaxation. Muscle-tendon-junction displacement was measured with ultrasonography. Tendon force was estimated using dynamometry and a musculoskeletal model. Gradients of the ramp-up force-displacement curves fitted between 0-40% and 50-90% of the preexercise maximal force determined stiffness in the low- and high-force-range, respectively. Hysteresis was determined using the ramp-up and relaxation force-displacement curves and elastic energy storage from the area under the ramp-up curve. In simulated batting, correlations between tendon properties and shuttle times were also assessed. After both protocols, Achilles tendon force decreased (4% to 5%, P < .050), but there were no changes in stiffness, hysteresis, or elastic energy. In simulated batting, Achilles tendon force and stiffness were both correlated to mean turn and mean sprint times (r = -0.719 to -0.830, P < .050). Neither protocol resulted in fatigue-related changes in tendon properties, but higher tendon stiffness and plantar flexion force were related to faster turn and sprint times, possibly by improving force transmission and control of movement when decelerating and accelerating.

  2. Achilles tendon reflex measuring system

    NASA Astrophysics Data System (ADS)

    Szebeszczyk, Janina; Straszecka, Joanna

    1995-06-01

    The examination of Achilles tendon reflex is widely used as a simple, noninvasive clinical test in diagnosis and pharmacological therapy monitoring in such diseases as: hypothyroidism, hyperthyroidism, diabetic neuropathy, the lower limbs obstructive angiopathies and intermittent claudication. Presented Achilles tendon reflect measuring system is based on the piezoresistive sensor connected with the cylinder-piston system. To determinate the moment of Achilles tendon stimulation a detecting circuit was used. The outputs of the measuring system are connected to the PC-based data acquisition board. Experimental results showed that the measurement accuracy and repeatability is good enough for diagnostics and therapy monitoring purposes. A user friendly, easy-to-operate measurement system fulfills all the requirements related to recording, presentation and storing of the patients' reflexograms.

  3. Peroneus Tertius Tendon Tear: A Rare Cause of Lateral Ankle Pain.

    PubMed

    Derrick, Edward; Flores, Miguel; Scherer, Kurt; Bancroft, Laura

    2016-01-01

    The peroneus tertius (PT) muscle is a variably present muscle, uncommonly found in humans. Injury to the PT tendon is rare with virtually no cases reported in the literature. As a consequence of the rarity of this injury, there is little clinical information regarding injury or rupture of the PT muscle and tendon. We present a case of injury involving this rare anatomical variant. Magnetic resonance (MR) imaging demonstrates a short segment longitudinal split tear adjacent to the tendinous insertion of the peroneus tertius muscle. Knowledge of this rare anatomic variant and the potential for associated pathology is critical in the management of the patient. Directing the orthopedic surgeon, or podiatrist, to this finding is critical for directing intervention. PMID:27226938

  4. Peroneus Tertius Tendon Tear: A Rare Cause of Lateral Ankle Pain

    PubMed Central

    Flores, Miguel; Scherer, Kurt; Bancroft, Laura

    2016-01-01

    The peroneus tertius (PT) muscle is a variably present muscle, uncommonly found in humans. Injury to the PT tendon is rare with virtually no cases reported in the literature. As a consequence of the rarity of this injury, there is little clinical information regarding injury or rupture of the PT muscle and tendon. We present a case of injury involving this rare anatomical variant. Magnetic resonance (MR) imaging demonstrates a short segment longitudinal split tear adjacent to the tendinous insertion of the peroneus tertius muscle. Knowledge of this rare anatomic variant and the potential for associated pathology is critical in the management of the patient. Directing the orthopedic surgeon, or podiatrist, to this finding is critical for directing intervention.  PMID:27226938

  5. Bilateral spontaneous patellar tendon rupture in the absence of concomitant systemic disease or steroid use.

    PubMed

    Greenbaum, B; Perry, J; Lee, J

    1994-11-01

    A case of bilateral patellar tendon rupture in an otherwise healthy 41-year-old man is presented. This is the 15th case reported in the literature. The mechanism of injury is attributed to a flexion moment coupled with a contraction of the quadriceps muscle in nearly all reported cases. Surgical repair produces excellent results. PMID:7854842

  6. [Spasm of the adductor muscles, pre-dislocations and dislocations of the hip joints in children and adolescents with cerebral palsy. Clinical observations on aetiology, pathogenesis, therapy and rehabilitation. Part II. The importance of the iliopsoas tendon, its tenotomy, of the coxa valga antetorta, and correction through osteotomy turning the hip into varus (author's transl)].

    PubMed

    Fettweis, E

    1979-02-01

    The following factors besides spasm and contraction of the adductor muscles contribute to the occurrence of dislocations of the hip in spastic paralysis: Spasm and contraction of the iliopsoas muscle and enhanced valgus position and antetorsion. The author holds the opinion that in case of malformation of the proximal end of the femur, it is not only the indirect action of the spastic musculature via the proximal femur-epiphyseal cartilage which is responsible for this phenomen in accordance with the law on functional adaption through longitudinal growth (Pauwels), but also the direct traction of the iliopsoas tendon. A clue in this direction is the often very pronounced elongation or enlargement of the trochanter minor. The author demonstrates the pathogenetic importance of iliopsoas contracture and malpositioning of the neck of the femur by means of analyses of the course in two patients. The following principles of treatment are postulated for spastic dislocation of the hip: Elimination of the pathogenetic factors through myotenotomy of the adductor muscles and complete resection of the obturator nerve, with observation of strict aftertreatment criteria, tenotomy of the iliopsoas, repositioning and osteotomy with turning into varus. Osteotomy without previous elimination of the pathogenetically acting muscular forces does not appear useful. Likewise, permanent re-positioning by means of muscle-relaxing operation cannot be sufficiently safe-guarded without additional osteotomy once the dislocation has taken place. In twelve patients with spastic dislocation of the hip, treated in accordance with these guidelines (two without osteotomy) aged 6 6/12 and 19 5/12 years, a roentgenologically good result was obtained in half of the cases, whereas the functional result was satisfactory not only with these patients but also with part of the other patients. If surgical treatment is instituted early enough, and if the experiences described here are taken into consideration

  7. Renal allograft fibrosis: biology and therapeutic targets.

    PubMed

    Boor, P; Floege, J

    2015-04-01

    Renal tubulointerstitial fibrosis is the final common pathway of progressive renal diseases. In allografts, it is assessed with tubular atrophy as interstitial fibrosis/tubular atrophy (IF/TA). IF/TA occurs in about 40% of kidney allografts at 3-6 months after transplantation, increasing to 65% at 2 years. The origin of renal fibrosis in the allograft is complex and includes donor-related factors, in particular in case of expanded criteria donors, ischemia-reperfusion injury, immune-mediated damage, recurrence of underlying diseases, hypertensive damage, nephrotoxicity of immunosuppressants, recurrent graft infections, postrenal obstruction, etc. Based largely on studies in the non-transplant setting, there is a large body of literature on the role of different cell types, be it intrinsic to the kidney or bone marrow derived, in mediating renal fibrosis, and the number of mediator systems contributing to fibrotic changes is growing steadily. Here we review the most important cellular processes and mediators involved in the progress of renal fibrosis, with a focus on the allograft situation, and discuss some of the challenges in translating experimental insights into clinical trials, in particular fibrosis biomarkers or imaging modalities.

  8. Effects of complement activation on allograft injury

    PubMed Central

    Sheen, Joong Hyuk; Heeger, Peter S.

    2015-01-01

    Purpose of review To summarize the current knowledge regarding mechanisms linking the complement system to transplant injury, highlighting findings reported since 2013. Recent findings Building upon the documentation that complement activation is a pathogenic mediator of post-transplant ischemia-reperfusion (IR) injury, emerging evidence indicates blocking either the classical or lectin pathways attenuates IR injury in animal models. Immune cell-derived and locally activated complement, including intracellular C3 positively modulates allo-reactive T cell activation and expansion, while simultaneously inhibiting regulatory T cell induction and function, together promoting transplant rejection. While alloantibody-initiated complement activation directly injures target cells, complement-dependent signals activate endothelial cells to facilitate T cell dependent inflammation. Complement activation within allografts contributes to progressive chronic injury and fibrosis. Summary The complement cascade, traditionally considered relevant to transplantation only as an effector mechanism of antibody-initiated allograft injury, is now understood to damage the allograft through multiple mechanisms. Complement activation promotes post-transplant IR injury, formation and function of allo-antibody, differentiation and function of alloreactive T cells, and contributes to chronic progressive allograft failure. The recognition that complement impacts transplant injury at many levels provides a foundation for targeting complement as a therapy to prolong transplant survival and improve patient health. PMID:26132735

  9. Meniscal Allograft Transplantation: State of the Art.

    PubMed

    Trentacosta, Natasha; Graham, William C; Gersoff, Wayne K

    2016-06-01

    Meniscal allograft transplantation has evolved over the years to provide a state-of-the-art technique for the sports medicine surgeon to utilize in preserving contact mechanics and function of the knee in irreparable meniscal pathology. However, this procedure continues to spark considerable debate on proper tissue processing techniques, acceptable indications, methods of implantation, and potential long-term outcomes. PMID:27135295

  10. Acute colitis in the renal allograft recipient.

    PubMed Central

    Perloff, L J; Chon, H; Petrella, E J; Grossman, R A; Barker, C F

    1976-01-01

    Four renal allograft recipients with evidence of ischemic damage to the colon are presented and compared with 11 cases from 5 major series. Similarities in the patients included: deterioration of renal function, multiple immunosuppressive and antibiotic regimens, the use of cadaver renal allografts, and diagnostic and therapeutic measures requiring frequent enemas with barium and ion-exchange resins. Two of our patients underwent surgery for the removal of segments of necrotic colon after several weeks of fever and abdominal pain initially attributed to either acute rejection, viral infection, or pancreatitis. One patient had three days of melena and responded to non-operative therapy. The fourth patient developed ischemic colonic changes 10 weeks after allograft nephrectomy and was receiving no immunosuppression at the time. Broad spectrum antibiotics were used at various times in all patients. Early aggressive evaluation of gastrointestinal complaints--including barium enema, upper gastrointestinal series with small bowel follow-through, proctosigmoidoscopy or colonoscopy, and arteriography--is indicated, in view of the lethality of the complication of colonic ulceration. The clinical pictures presented emphasize the fact that recipients of renal allografts are commonly heir to many complications which may be considered rare in the normal population. Images Fig. 1. Fig. 2. Fig. 3. Fig. 4a. Fig. 4b. PMID:1108814

  11. The clinical effect of tendon repair for tendon spontaneous rupture after corticosteroid injection in hands

    PubMed Central

    Lu, Hui; Yang, Hu; Shen, Hui; Ye, Ganmin; Lin, Xiang-Jin

    2016-01-01

    Abstract Corticosteroid injections for hand tendinitis can lead to a rare significant complication of tendon spontaneous rupture. However, only sporadic cases were reported in the literature before. This study was designed to gauge the clinical effect of tendon repair in patients of tendon spontaneous rupture after corticosteroid injection and analyze our experience. This was a retrospective observational study of 13 patients (8 women and 5 men) operated between July 2011 and December 2015 for tendon spontaneous rupture after corticosteroid injection. Demographic data, clinical features, imaging data, and surgical treatments were carefully reviewed. The average age was 52.308 ± 15.381 years (range 29–71). The average injection times were 2.538 ± 1.664 times (range 1–6). The average rupture time (after last injection) was 10.923 ± 9.500 weeks (range 3–32). Nine patients were treated by tendon suture (69% of cases), and 4 patients were treated by tendon grafting (31% of cases). All patients received follow-up in our outpatient clinic. The sites of the tendon rupture (15 tendons of 13 patients had involved) include extensor pollicis longus (6 tendons, 40% of cases), extensor digiti quinti and extensor digiti minimi (4 tendons, 27% of cases), ring finger of extensor digitorum communis (3 tendons, 20% of cases), and middle finger of extensor digitorum communis (2 tendons, 13% of cases). Two patients who had tendon adhesion (15% of cases) were treated by tendon release. One patient who had tendon rerupture (8% of cases) was treated by tendon grafting. No patient had complications of infections, vascular, or nerve injury. Tendon spontaneous rupture is a serious complication after corticosteroid injection for tendinitis. Rigid standard of corticosteroid injection is very important. Magnetic resonance imaging was contributory to preoperative assess tendon defect and can be used to monitor healing quality of tendons during the follow-up. PMID:27741145

  12. 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

  13. Arthroscopic meniscal allograft transplantation without bone plugs.

    PubMed

    Alentorn-Geli, Eduard; Seijas Vázquez, Roberto; García Balletbó, Montserrat; Álvarez Díaz, Pedro; Steinbacher, Gilbert; Cuscó Segarra, Xavier; Rius Vilarrubia, Marta; Cugat Bertomeu, Ramón

    2011-02-01

    Partial or total meniscectomy are common procedures performed at Orthopedic Surgery departments. Despite providing a great relief of pain, it has been related to early onset knee osteoarthritis. Meniscal allograft transplantation has been proposed as an alternative to meniscectomy. The purposes of this study were to describe an arthroscopic meniscal allograft transplantation without bone plugs technique and to report the preliminary results. All meniscal allograft transplantations performed between 2001 and 2006 were approached for eligibility, and a total of 35 patients (involving 37 menisci) were finally engaged in the study. Patients were excluded if they had ipsilateral knee ligament reconstruction or cartilage repair surgery before meniscal transplantation or other knee surgeries after the meniscal transplantation. Scores on Lysholm, Subjective IKDC Form, and Visual Analogue Scale (VAS) scale for pain were obtained at a mean follow-up of 38.6 months and compared to pre-operative data. Data on chondral lesions were obtained during the arthroscopic procedure and through imaging (radiographs and MRI) studies pre-operatively. Two graft failures out of 59 transplants (3.4%) were found. Daily life accidents were responsible for all graft failures. Significant improvements for Lysholm, Subjective IKDC Form, and VAS for pain scores following the meniscal allograft transplantation were found (P < 0.0001). Controlling for chondral lesion, there was no significant interactions for Lysholm (n.s.), Subjective IKDC Form (n.s.), and VAS for pain scores (n.s.). This study demonstrated that an arthroscopic meniscal allograft transplantation without bone plugs improved knee function and symptoms after a total meniscectomy. Improvements were observed independently of the degree of chondral lesion.

  14. Multiple Fibromas of Tendon Sheath: Unusual Presentation

    PubMed Central

    Park, Se Young; Jin, Seon Pil; Yeom, Bora; Kim, Shin Woo; Cho, So Yun

    2011-01-01

    Fibroma of the tendon sheath is an uncommon soft tissue tumor presenting as a solitary, slow-growing, firm, painless, small nodule, which shows strong attachment to the tendon or tendon sheath. It is usually localized on fingers and hand tendons in adults between the age of 20 and 40 years old. This case concerns a 61-year-old man presenting with a 5-year history of multiple cutaneous nodules on both palms and soles. Skin biopsy confirmed fibroma of the tendon sheath. Blood tests showed a high titer of rheumatoid factor and positivity to anti-nuclear antibody. No case of fibroma of the tendon sheath occurring multifocally on both palms and soles has been previously reported. Herein, we report on a very rare case of multiple fibromas of the tendon sheath arising from palms and soles, which supports the pathogenetic hypothesis that this tumor may be a reactive process rather than a true neoplasm. PMID:22028571

  15. Histologic analysis of ruptured quadriceps tendons.

    PubMed

    Trobisch, Per David; Bauman, Matthias; Weise, Kuno; Stuby, Fabian; Hak, David J

    2010-01-01

    Quadriceps tendon ruptures are uncommon injuries. Degenerative changes in the tendon are felt to be an important precondition for rupture. We retrospectively reviewed 45 quadriceps tendon ruptures in 42 patients. Quadriceps tendon ruptures occurred most often in the sixth and seventh decade of life. Men were affected six times as often as women. A tissue sample from the rupture-zone was obtained in 22 cases and histologic analysis was performed. Degenerative changes were present in only 14 (64%) of the 22 samples. We observed an increasing ratio of degenerative to nondegenerative tendons with increasing patient age. Our data suggests that quadriceps tendon rupture, especially in younger patients, can occur in the absence of pathologic tendon degeneration.

  16. Bioreactor Design for Tendon/Ligament Engineering

    PubMed Central

    Wang, Tao; Gardiner, Bruce S.; Lin, Zhen; Rubenson, Jonas; Kirk, Thomas B.; Wang, Allan; Xu, Jiake

    2013-01-01

    Tendon and ligament injury is a worldwide health problem, but the treatment options remain limited. Tendon and ligament engineering might provide an alternative tissue source for the surgical replacement of injured tendon. A bioreactor provides a controllable environment enabling the systematic study of specific biological, biochemical, and biomechanical requirements to design and manufacture engineered tendon/ligament tissue. Furthermore, the tendon/ligament bioreactor system can provide a suitable culture environment, which mimics the dynamics of the in vivo environment for tendon/ligament maturation. For clinical settings, bioreactors also have the advantages of less-contamination risk, high reproducibility of cell propagation by minimizing manual operation, and a consistent end product. In this review, we identify the key components, design preferences, and criteria that are required for the development of an ideal bioreactor for engineering tendons and ligaments. PMID:23072472

  17. Effect of altering starting length and activation timing of muscle on fiber strain and muscle damage.

    PubMed

    Butterfield, Timothy A; Herzog, Walter

    2006-05-01

    Muscle strain injuries are some of the most frequent injuries in sports and command a great deal of attention in an effort to understand their etiology. These injuries may be the culmination of a series of subcellular events accumulated through repetitive lengthening (eccentric) contractions during exercise, and they may be influenced by a variety of variables including fiber strain magnitude, peak joint torque, and starting muscle length. To assess the influence of these variables on muscle injury magnitude in vivo, we measured fiber dynamics and joint torque production during repeated stretch-shortening cycles in the rabbit tibialis anterior muscle, at short and long muscle lengths, while varying the timing of activation before muscle stretch. We found that a muscle subjected to repeated stretch-shortening cycles of constant muscle-tendon unit excursion exhibits significantly different joint torque and fiber strains when the timing of activation or starting muscle length is changed. In particular, measures of fiber strain and muscle injury were significantly increased by altering activation timing and increasing the starting length of the muscle. However, we observed differential effects on peak joint torque during the cyclic stretch-shortening exercise, as increasing the starting length of the muscle did not increase torque production. We conclude that altering activation timing and muscle length before stretch may influence muscle injury by significantly increasing fiber strain magnitude and that fiber dynamics is a more important variable than muscle-tendon unit dynamics and torque production in influencing the magnitude of muscle injury.

  18. A study of the relationship between mineral content and mechanical properties of turkey gastrocnemius tendon

    NASA Technical Reports Server (NTRS)

    Landis, W. J.; Librizzi, J. J.; Dunn, M. G.; Silver, F. H.

    1995-01-01

    The vertebrate skeletal system undergoes adaptation in response to external forces, but the relation between the skeletal changes and such forces is not understood. In this context, the variation in the amount and location of calcification has been compared with changes in mechanical properties of the normally mineralizing turkey gastrocnemius tendon using ash weight measurements, X-ray radiography, and mechanical testing. Radiographic evidence from 12- to 17-week-old birds showed calcification in only portions of gastrocnemius tendons proximal to the tarsometatarsal joint. Mechanical testing of these dissected proximal regions demonstrated an increased ultimate stress and modulus and a decreased maximum strain that appeared to parallel calcification. Further, stress-strain curves of portions of uncalcified turkey gastrocnemius tendon were shaped similar to those of other typical unmineralized tendon curves while highly calcified tendons yielded curves resembling those of bone. The proximal portions of the gastrocnemius where mineralization begins were observed to have a decreased tendon cross-sectional area compared with distal portions which do not mineralize. Based on the resultant measures of mineral content and location and mechanical properties, it is hypothesized that increased calcification is a result of increased stresses at certain locations of the tendon, perhaps the consequence of the natural forces exerted by the large leg muscles of the bird into which the gastrocnemius inserts. More specifically, tendon calcification may be the result of stress-induced exposure of charged sites on the surfaces of collagen molecules, fibrils, or fibers so that deposition of mineral and subsequent mechanical reinforcement occur in the tissue.(ABSTRACT TRUNCATED AT 250 WORDS).

  19. Tendon Tissue Engineering and Its Role on Healing of the Experimentally Induced Large Tendon Defect Model in Rabbits: A Comprehensive In Vivo Study

    PubMed Central

    Meimandi-Parizi, Abdolhamid; Oryan, Ahmad; Moshiri, Ali

    2013-01-01

    Healing of large tendon defects is challenging. We studied the role of collagen implant with or without polydioxanone (PDS) sheath on the healing of a large Achilles tendon defect model, in rabbits. Sixty rabbits were divided into three groups. A 2 cm gap was created in the left Achilles tendon of all rabbits. In the control lesions, no implant was used. The other two groups were reconstructed by collagen and collagen-PDS implants respectively. The animals were clinically examined at weekly intervals and their lesions were observed by ultrasonography. Blood samples were obtained from the animals and were assessed for hematological analysis and determination of serum PDGF level, at 60 days post injury (DPI). The animals were then euthanized and their lesions were assessed for gross and histopathology, scanning electron microscopy, biomechanical testing, dry matter and hydroxyproline content. Another 65 pilot animals were also studied grossly and histopathologically to define the host implant interaction and graft incorporation at serial time points. The treated animals gained significantly better clinical scoring compared to the controls. Treatment with collagen and collagen-PDS implants significantly increased the biomechanical properties of the lesions compared to the control tendons at 60DPI (P<0.05). The tissue engineered implants also reduced peritendinous adhesion, muscle fibrosis and atrophy, and increased ultrasonographical echogenicity and homogenicity, maturation and differentiation of the collagen fibrils and fibers, tissue alignment and volume of the regenerated tissue compared to those of the control lesions (P<0.05). The implants were gradually absorbed and substituted by the new tendon. Implantation of the bioimplants had a significant role in initiating tendon healing and the implants were biocompatible, biodegradable and safe for application in tendon reconstructive surgery. The results of the present study may be valuable in clinical practice. PMID

  20. The Effect of Mechanical Vibration Stimulation of Perception Subthreshold on the Muscle Force and Muscle Reaction Time of Lower Leg.

    PubMed

    Kim, Huigyun; Kwak, Kiyoung; Kim, Dongwook

    2016-01-01

    The objective of this study is to investigate the effect of mechanical vibration stimulation on the muscle force and muscle reaction time of lower leg according to perception threshold and vibration frequency. A vibration stimulation with perception threshold intensity was applied on the Achilles tendon and tibialis anterior tendon. EMG measurement and analysis system were used to analyze the change of muscle force and muscle reaction time according to perception threshold and vibration frequency. A root-mean-square (RMS) value was extracted using analysis software and Maximum Voluntary Contraction (MVC) and Premotor Time (PMT) were analyzed. The measurement results showed that perception threshold was different from application sites of vibration frequency. Also, the muscle force and muscle reaction time showed difference according to the presence of vibration, frequency, and intensity. This result means that the vibration stimulation causes the change on the muscle force and muscle reaction time and affects the muscles of lower leg by the characteristics of vibration stimulation.

  1. Muscle gearing during isotonic and isokinetic movements in the ankle plantarflexors.

    PubMed

    Randhawa, Avleen; Jackman, Meghan E; Wakeling, James M

    2013-02-01

    Muscle-tendon gearing is the ratio of the muscle-tendon unit velocity to the fascicle velocity and can be expressed as the product of the gearing within the muscle belly and the gearing due to tendon stretch. Previous studies have shown that gearing is variable and increases at higher velocities. Changes in the muscle activation levels and force development have been suggested to affect tendon gearing and thus muscle-tendon unit gearing. However, the role of belly gearing as a part of muscle-tendon gearing and its associations with structural aspects of muscle and thus movement performance are important facets that need to be studied. The two gastrocnemii of twenty young adults were tested during isokinetic and isotonic contractions on an ankle dynamometer. Ultrasound images of both muscles were collected during contractions and were later digitised. Gearing was also predicted using a 2-dimensional panel model of these muscles. The results from experimental and models tests showed increases in gearing with greater torque levels at slower contraction velocities. However, in the isotonic models there was a substantial increase in gearing at faster contraction velocities. The level of muscle-tendon unit gearing is largely determined by the belly gearing, but its variability is driven by changes in tendon gearing that in turn is a factor of the muscle activation and coordination. The belly thickness of the medial gastrocnemius decreased during contractions, but increased for the lateral gastrocnemius. It is likely that changes to the belly shape and 3-dimensional structure are important to the gearing of the muscle.

  2. MR imaging of sports-related muscle injuries.

    PubMed

    Yang, C W; Liu, G C; Chen, H Y; Wang, M L; Lin, M B; Kuo, Y T

    1994-04-01

    Magnetic resonance (MR) imaging of the thighs of 26 baseball athletes and one softball athlete were studied to evaluate muscle injuries. We documented the abnormalities present in MR imaging after a muscle injury and evaluated the role of MR imaging in muscle injuries. Fifteen of the athletes showed muscle abnormalities in MR images. These include muscle strains without tear, muscle tear, scar and chronic tendon injury. Having the advantages of high tissue contrast and multiplanar display capability, MR allowed direct visualization of the injured muscles and characterization of traumatic lesions. We conclude that MR could be a good imaging modality for evaluating muscle injuries.

  3. Factors Predicting Meniscal Allograft Transplantation Failure

    PubMed Central

    Parkinson, Ben; Smith, Nicholas; Asplin, Laura; Thompson, Peter; Spalding, Tim

    2016-01-01

    Background: Meniscal allograft transplantation (MAT) is performed to improve symptoms and function in patients with a meniscal-deficient compartment of the knee. Numerous studies have shown a consistent improvement in patient-reported outcomes, but high failure rates have been reported by some studies. The typical patients undergoing MAT often have multiple other pathologies that require treatment at the time of surgery. The factors that predict failure of a meniscal allograft within this complex patient group are not clearly defined. Purpose: To determine predictors of MAT failure in a large series to refine the indications for surgery and better inform future patients. Study Design: Cohort study; Level of evidence, 3. Methods: All patients undergoing MAT at a single institution between May 2005 and May 2014 with a minimum of 1-year follow-up were prospectively evaluated and included in this study. Failure was defined as removal of the allograft, revision transplantation, or conversion to a joint replacement. Patients were grouped according to the articular cartilage status at the time of the index surgery: group 1, intact or partial-thickness chondral loss; group 2, full-thickness chondral loss 1 condyle; and group 3, full-thickness chondral loss both condyles. The Cox proportional hazards model was used to determine significant predictors of failure, independently of other factors. Kaplan-Meier survival curves were produced for overall survival and significant predictors of failure in the Cox proportional hazards model. Results: There were 125 consecutive MATs performed, with 1 patient lost to follow-up. The median follow-up was 3 years (range, 1-10 years). The 5-year graft survival for the entire cohort was 82% (group 1, 97%; group 2, 82%; group 3, 62%). The probability of failure in group 1 was 85% lower (95% CI, 13%-97%) than in group 3 at any time. The probability of failure with lateral allografts was 76% lower (95% CI, 16%-89%) than medial allografts at

  4. Pectoralis Major Tendon Repair

    PubMed Central

    Cordasco, Frank A.; Degen, Ryan; Mahony, Gregory Thomas; Tsouris, Nicholas

    2016-01-01

    Objectives: Systematic reviews of the literature have identified 365 reported cases of Pectoralis Major Tendon (PMT) injuries. While surgical treatment has demonstrated improved outcomes compared to non-operative treatment, there is still relatively limited data on the functional outcome, return to sport and need for 2nd surgery in athletes following PMT repair. This study comprises the largest series of athletes following PMT repair reported to date. The Objective is to report on the functional outcomes, return to sport and need for 2nd surgery in a consecutive series of PMT tears. Methods: From 2009, 81 patients with PMT tears were enrolled in this prospective series. Baseline evaluation included patient demographics, mechanism of injury, physical examination and PMT specific MRI for confirmation of the diagnosis and analysis of the extent of injury. Each patient underwent surgical repair by the senior author utilizing a previously published surgical technique. Patients were then followed at 2 weeks, 6 weeks, 3 months and 6 months and further follow-up was conducted annually thereafter with functional outcome scores and adduction strength testing. The return to sport and incidence of 2nd surgery data were recorded. This study includes the first 40 athletes to reach the 2-year post-operative period. Results: All athletes were male, with an average age of 34.4 years (range 23-59). The patient cohort consisted of 4 professional NFL players and 36 recreational athletes. Average follow-up duration was 2.5 years (range 2 - 6.0 years). The most common mechanisms of injury occurred during the bench press (n=26) and contact sport participation (n=14). Sixteen injuries were complete avulsions involving both the clavicular and sternocostal heads, while 24 were isolated sternocostal head avulsions. Average pre-injury bench press of 396 lbs (range 170-500 lbs) was restored to 241 lbs post-operatively (range 140-550 lbs). Single Assessment Numeric Evaluation (SANE) scores

  5. Invasive Streptococcus pyogenes after allograft implantation--Colorado, 2003.

    PubMed

    2003-12-01

    Allograft tissues are used for various orthopedic procedures (e.g., ligament reconstruction, meniscal transplantation, and spinal surgery). In 2002, approximately one million allografts were distributed for transplantation (American Association of Tissue Banks [AATB], unpublished data, 2002). Recent reports of allograft-associated infections have prompted evaluation of the processing and quality-control methods employed by tissue processors. This report describes a case of invasive disease with Streptococcus pyogenes (i.e., group A streptococcus [GAS]), after reconstructive knee surgery using contaminated allograft tissue and provides recommendations to reduce the risk for allograft-associated infections. Although allograft infections are rare, they highlight the need for improved tissue evaluation and processing standards. PMID:14654764

  6. Treatment of chronic extensor tendons lesions of the fingers.

    PubMed

    Bellemère, P

    2015-09-01

    Chronic finger extensor apparatus injuries are the result of the initial acute treatment having failed or being flawed. Because of their chronic nature, these injuries present various amounts of tendon retraction, tendon callus lengthening, peritendinous scar adhesions, static and dynamic imbalances with the flexor apparatus and intrinsic muscles, and joint contractures. This article will review the anatomy of the extensor mechanism and then will outline by location, the various clinical pictures that are secondary to chronic tendon injury. The clinical presentation of these injuries can be highly variable but their symptomatology and treatment are very specific. Of the possible therapeutic strategies for chronic mallet finger with or without associated swan-neck deformity, chronic boutonniere deformity, chronic sagittal band injuries, old ruptures on the dorsum of the wrist and traumatic defects in multiple tissues, conservative treatment is often the main element. Secondary surgical repair is not free of complications, and the results are often lacking. Rehabilitation and orthotic bracing are an integral part of the management of these injuries, no matter which treatment method is being considered. PMID:26184651

  7. Lacerations to Zones VIII and IX: It Is Not Just a Tendon Injury

    PubMed Central

    Fischer, Charla R.; Tang, Peter

    2011-01-01

    Extensor tendon injuries are widely believed to be straightforward problems that are relatively simple to manage. However, these injuries can be complex and demand a thorough understanding of anatomy to achieve the best functional outcomes. When lacerations occur in the forearm as in Zones VIII and IX injury, the repair of the extensor tendon and muscle, and posterior interosseous nerve (PIN) is often challenging. A review of the literature shows little guidance and attention for these injuries. We present four patients with injuries to Zones VIII and IX as well as a review of surgical technique, postoperative rehabilitation, and pearls that may be of benefit to those managing these injuries. PMID:21991409

  8. Mesh or no mesh: a hamletic dilemma to prevent Renal Allograft Compartment Syndrome (RACS).

    PubMed

    Palumbo, Vincenzo Davide; Damiano, Giuseppe; Gioviale, Maria Concetta; Lo Monte, Attilio Ignazio

    2013-06-25

    Tension-free muscle closure is essential in kidney transplantation, both in adult and pediatric patients. Tight muscle closure may lead to renal allograft compartment syndrome either due to compression of the renal parenchyma or due to kinking of the renal vessels. It may also cause kinking of the transplant kidney ureter, wound dehiscence and incisional hernia. Many techniques have been proposed in an attempt to achieve tension-free closure. There is a wrong belief among surgeons that using prosthetic mesh may increase the incidence of infective complications in these immunosuppressed patients. Also, there is fear that one is not able to monitor the renal graft by ultrasound and perform biopsy in the presence of a mesh. Other alternative techniques to mesh closure include subcutaneous placement and intraperitonealization of the kidney transplant. These techniques however, are valuable when mesh closure is unfavorable or contraindicated as in case of a potential source of infection, like a stoma. Abdominal wall fasciotomy can be adjunctive to the various techniques of muscle closure. Key words: Abdominal mesh closure, Post transplant incisional hernia, Renal transplantation, Renal allograft compartment syndrome (RACS).

  9. Mechanical Actuation Systems for the Phenotype Commitment of Stem Cell-Based Tendon and Ligament Tissue Substitutes.

    PubMed

    Govoni, Marco; Muscari, Claudio; Lovecchio, Joseph; Guarnieri, Carlo; Giordano, Emanuele

    2016-04-01

    High tensile forces transmitted by tendons and ligaments make them susceptible to tearing or complete rupture. The present standard reparative technique is the surgical implantation of auto- or allografts, which often undergo failure.Currently, different cell types and biomaterials are used to design tissue engineered substitutes. Mechanical stimulation driven by dedicated devices can precondition these constructs to a remarkable degree, mimicking the local in vivo environment. A large number of dynamic culture instruments have been developed and many appealing results collected. Of the cells that have been used, tendon stem cells are the most promising for a reliable stretch-induced tenogenesis, but their reduced availability represents a serious limitation to upscaled production. Biomaterials used for scaffold fabrication include both biological molecules and synthetic polymers, the latter being improved by nanotechnologies which reproduce the architecture of native tendons. In addition to cell type and scaffold material, other variables which must be defined in mechanostimulation protocols are the amplitude, frequency, duration and direction of the applied strain. The ideal conditions seem to be those producing intermittent tension rather than continuous loading. In any case, all physical parameters must be adapted to the specific response of the cells used and the tensile properties of the scaffold. Tendon/ligament grafts in animals usually have the advantage of mechanical preconditioning, especially when uniaxial cyclic forces are applied to cells engineered into natural or decellularized scaffolds. However, due to the scarcity of in vivo research, standard protocols still need to be defined for clinical applications.

  10. Restoration of pinch in intrinsic muscles of the hand.

    PubMed

    Lee, Steve K; Wisser, Jamie R

    2012-02-01

    The primary intrinsic muscles responsible for key and tip pinch are the adductor pollicis, first dorsal interosseous and flexor pollicis brevis muscles. Numerous conditions can lead to their dysfunction. Non-operative treatment consists of exercises of the compensating extensor pollicis longus and flexor pollicis longus muscles and use of adaptive devices, such as larger grips. Operative treatments include tendon transfers and joint fusions. The most common tendon transfer procedures include transfering of the extensor carpi radialis brevis to the adductor pollicis muscle or transfering of the abductor pollicis longus to the first dorsal interosseous muscle. Both require use of extension tendon grafts. In cases of joint instability or arthrosis, arthrodesis of the thumb and index finger MP or IP joints, alone or in combination, may be indicated. PMID:22117923

  11. Recirculation of indium-111-labeled lymphocytes in normal and allografted rats

    SciTech Connect

    Oluwole, S.; Satake, K.; Kuromoto, N.; Fawwaz, R.; Hardy, M.A.

    1983-11-01

    The kinetics of lymphocyte recirculation in normal and allografted rats with acute cardiac rejection was studied with indium-111 (In-111) labeled splenic lymphocytes in two groups of rats. Group 1 consisted of subgroups of normal Lewis rats infused with In-111 labeled unsensitized syngeneic cells (group 1a); ACI-sensitized syngeneic cells (group 1b); and ACI spleen cells (group 1c). Four rats from each subgroup were killed at 3, 6, 18, and 24 hr after cell infusion for blood, spleen, mesenteric lymph node (MLN), thymus, bone marrow (BM), liver, kidney, muscle, and heart scintillation counts. Group 2 consisted of Lewis recipients of ACI cardiac allografts infused with normal or with ACI-sensitized syngeneic splenic cells. Four rats from each subgroup were killed daily until rejection (day 7) for isotope counts of various organs. In ungrafted rats (group I), splenic accumulation of unsensitized syngeneic cells fell from 50% of the total injected dose/g tissue at 3 hr to 28% at 24 hr, whereas it rose from 12% at 3 hr to 39% at 24 hr in MLN. In contrast, the sensitized syngeneic and allogeneic cells homed preferentially to the spleen with insignificant accumulation in the MLN throughout the experiment. The BM and liver showed moderate accumulation while the thymus and nonlymphoid organs had low concentrations of labeled cells at all times. Splenic accumulation of unsensitized syngeneic cells in allografted rats (group II) showed a steep rise from day 1, reaching a peak at day 3, followed by a plateau--but sensitized cells demonstrated a peak on day 4 followed by a sharp decline until rejection. Accumulation of unsensitized cells in the MLN was significantly higher than that of sensitized cells throughout the study. There was a significant fall in radioactivity of BM, thymus, liver, and nonlymphoid organs from days 1-7, and the cardiac allograft demonstrated a reciprocal sharp rise in radioactivity.

  12. The Effects of Glucocorticoid on Tendon and Tendon Derived Cells.

    PubMed

    Dean, Benjamin John Floyd; Carr, Andrew Jonathan

    2016-01-01

    Glucocorticoids are generally used to relieve pain and/or inflammation in a wide variety of musculoskeletal disorders including osteoarthritis, inflammatory arthritis, tendinopathy and degenerative spine disease. Glucocorticoids reduce tendon derived cell proliferation in vitro and reduce extracellular matrix synthesis both in vitro and in vivo, in particular type I collagen synthesis. Glucocorticoids also appear to result in acute deleterious changes in healthy in vivo tendon including collagen necrosis, collagen disorganisation and inflammatory cell infiltration; while the overall effect of glucocorticoid administration on the mechanical properties of healthy in vivo tendon are generally negative. Overall the existing in vitro and in vivo evidence suggests that glucocorticoids should be used with caution in treating painful tendinopathy. Certainly a real need exists to follow up the long term clinical effects of glucocorticoid in treating tendinopathy, as there is currently a paucity of evidence in this area. However in this context while the short term benefits are clear, glucocorticoids remain a useful treatment option provided they are used in the right patients in sensible moderation. PMID:27535266

  13. 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

  14. Posterior Deltoid-to-Triceps Tendon Transfer for Elbow Extension in a Tetraplegia Patient: A Case Report

    PubMed Central

    Jeong, Ji Hun; Ahn, Dong Heun; Kim, Yong Rok; Hong, Mi Jin; Lee, Yung Jin; Park, Chang-il; Heo, Youn Moo

    2016-01-01

    In tetraplegia patients, activities of daily living are highly dependent on the remaining upper limb functions. In other countries, upper limb reconstruction surgery to improve function has been applied to diverse cases, but few cases have been reported in Korea. The current authors experienced a case of posterior deltoid-to-triceps tendon transfer and rehabilitation in a complete spinal cord injury with a C6 neurologic level, and we introduce the case—a 36-year-old man—with a literature review. The patient's muscle strength in C5 C6 muscles were normal, but C7 muscles were trace, and the Spinal Cord Independence Measure III (SCIM III) score was 24. The tendon of the posterior deltoid was transferred to the triceps brachii muscle, and then the patient received comprehensive rehabilitative treatment. His C7 muscle strength in the right upper extremity was enhanced from trace to fair, and his SCIM III score improved to 29. PMID:27152287

  15. Posterior Deltoid-to-Triceps Tendon Transfer for Elbow Extension in a Tetraplegia Patient: A Case Report.

    PubMed

    Jeong, Ji Hun; Park, Jong Bum; Ahn, Dong Heun; Kim, Yong Rok; Hong, Mi Jin; Lee, Yung Jin; Park, Chang-Il; Heo, Youn Moo

    2016-04-01

    In tetraplegia patients, activities of daily living are highly dependent on the remaining upper limb functions. In other countries, upper limb reconstruction surgery to improve function has been applied to diverse cases, but few cases have been reported in Korea. The current authors experienced a case of posterior deltoid-to-triceps tendon transfer and rehabilitation in a complete spinal cord injury with a C6 neurologic level, and we introduce the case-a 36-year-old man-with a literature review. The patient's muscle strength in C5 C6 muscles were normal, but C7 muscles were trace, and the Spinal Cord Independence Measure III (SCIM III) score was 24. The tendon of the posterior deltoid was transferred to the triceps brachii muscle, and then the patient received comprehensive rehabilitative treatment. His C7 muscle strength in the right upper extremity was enhanced from trace to fair, and his SCIM III score improved to 29. PMID:27152287

  16. Modulation of soleus corticospinal excitability during Achilles tendon vibration.

    PubMed

    Lapole, Thomas; Temesi, John; Arnal, Pierrick J; Gimenez, Philippe; Petitjean, Michel; Millet, Guillaume Y

    2015-09-01

    Soleus (SOL) corticospinal excitability has been reported to increase during Achilles tendon vibration. The aim of the present study was to further investigate SOL corticospinal excitability and elucidate the changes to intracortical mechanisms during Achilles tendon vibration. Motor-evoked potentials (MEPs) were elicited in the SOL by transcranial magnetic stimulation (TMS) of the corresponding motor cortical area of the leg with and without 50-Hz Achilles tendon vibration. SOL input-output curves were determined. Paired-pulse protocols were also performed to investigate short-interval intracortical inhibition (SICI) and intracortical facilitation (ICF) by conditioning test TMS pulses with sub-threshold TMS pulses at inter-stimulus intervals of 3 and 13 ms, respectively. During Achilles tendon vibration, motor threshold was lower than in the control condition (43 ± 13 vs. 49 ± 11 % of maximal stimulator output; p = 0.008). Input-output curves were also influenced by vibration, i.e. there was increased maximal MEP amplitude (0.694 ± 0.347 vs. 0.268 ± 0.167 mV; p < 0.001), decreased TMS intensity to elicit a MEP of half the maximal MEP amplitude (100 ± 13 vs. 109 ± 9 % motor threshold; p = 0.009) and a strong tendency for decreased slope constant (0.076 ± 0.04 vs. 0.117 ± 0.04; p = 0.068). Vibration reduced ICF (98 ± 61 vs. 170 ± 105 % of test MEP amplitude; p = 0.05), but had no effect on SICI (53 ± 26 vs. 48 ± 22 % of test MEP amplitude; p = 0.68). The present results further document the increased vibration-induced corticospinal excitability in the soleus muscle and suggest that this increase is not mediated by changes in SICI or ICF.

  17. Procurement of hand and arm allografts.

    PubMed

    Cetrulo, Curtis L; Kovach, Stephen J

    2013-12-01

    Upper extremity transplantation has been at the forefront of vascularized composite allotransplantation. There have been more hand and upper extremity transplants than any other kinds of vascularized composite allotransplantation. However, it is a new and evolving field. Reconstructive surgeons are relative newcomers to the field of transplantation, and the procurement of upper extremity allografts has many subtleties that will differ depending on the intended recipient. However, there are certain principles that can be adhered to that this review serves to elucidate. PMID:24310234

  18. Procurement of hand and arm allografts.

    PubMed

    Cetrulo, Curtis L; Kovach, Stephen J

    2013-12-01

    Upper extremity transplantation has been at the forefront of vascularized composite allotransplantation. There have been more hand and upper extremity transplants than any other kinds of vascularized composite allotransplantation. However, it is a new and evolving field. Reconstructive surgeons are relative newcomers to the field of transplantation, and the procurement of upper extremity allografts has many subtleties that will differ depending on the intended recipient. However, there are certain principles that can be adhered to that this review serves to elucidate.

  19. Common conditions of the achilles tendon.

    PubMed

    Mazzone, Michael F; McCue, Timothy

    2002-05-01

    The Achilles tendon, the largest tendon in the body, is vulnerable to injury because of its limited blood supply and the combination of forces to which it is subjected. Aging and increased activity (particularly velocity sports) increase the chance of injury to the Achilles tendon. Although conditions of the Achilles tendon are occurring with increasing frequency because the aging U.S. population is remaining active, the diagnosis is missed in about one fourth of cases. Injury onset can be gradual or sudden, and the course of healing is often lengthy. A thorough history and specific physical examination are essential to make the appropriate diagnosis and facilitate a specific treatment plan. The mainstay of treatment for tendonitis, peritendonitis, tendinosis, and retrocalcaneobursitis is ice, rest, and nonsteroidal anti-inflammatory drugs, but physical therapy, orthoties, and surgery may be necessary in recalcitrant cases. In patients with tendon rupture, casting or surgery is required. Appropriate treatment often leads to full recovery.

  20. Tensile mechanical properties of human forearm tendons.

    PubMed

    Weber, J F; Agur, A M R; Fattah, A Y; Gordon, K D; Oliver, M L

    2015-09-01

    Previous studies of the mechanical properties of tendons in the upper limb have used embalmed specimens or sub-optimal methods of measurement. The aim of this study was to determine the biomechanical properties of all tendons from five fresh frozen cadaveric forearms using updated methodology. The cross-sectional area of tendons was accurately measured using a laser reflectance system. Tensile testing was done in a precision servo-hydraulic device with cryo-clamp fixation. We determined that the cross-sectional area of some tendons is variable and directly influences the calculated material properties; visual estimation of this is unreliable. Data trends illustrate that digital extensor tendons possess the greatest tensile strength and a higher Young's modulus than other tendon types. PMID:25940499

  1. Mesenchymal stem cell applications to tendon healing

    PubMed Central

    Chaudhury, Salma

    2012-01-01

    Summary Tendons are often subject to age related degenerative changes that coincide with a diminished regenerative capacity. Torn tendons often heal by forming scar tissue that is structurally weaker than healthy native tendon tissue, predisposing to mechanical failure. There is increasing interest in providing biological stimuli to increase the tendon reparative response. Stem cells in particular are an exciting and promising prospect as they have the potential to provide appropriate cellular signals to encourage neotendon formation during repair rather than scar tissue. Currently, a number of issues need to be investigated further before it can be determined whether stem cells are an effective and safe therapeutic option for encouraging tendon repair. This review explores the in-vitro and invivo evidence assessing the effect of stem cells on tendon healing, as well as the potential clinical applications. PMID:23738300

  2. Tensile mechanical properties of human forearm tendons.

    PubMed

    Weber, J F; Agur, A M R; Fattah, A Y; Gordon, K D; Oliver, M L

    2015-09-01

    Previous studies of the mechanical properties of tendons in the upper limb have used embalmed specimens or sub-optimal methods of measurement. The aim of this study was to determine the biomechanical properties of all tendons from five fresh frozen cadaveric forearms using updated methodology. The cross-sectional area of tendons was accurately measured using a laser reflectance system. Tensile testing was done in a precision servo-hydraulic device with cryo-clamp fixation. We determined that the cross-sectional area of some tendons is variable and directly influences the calculated material properties; visual estimation of this is unreliable. Data trends illustrate that digital extensor tendons possess the greatest tensile strength and a higher Young's modulus than other tendon types.

  3. 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.

  4. Dynamic behavior of tendons in random seas

    SciTech Connect

    Niedzwecki, J.M.; Rijken, O.R.; Soemantri, D.S.

    1995-12-31

    The dynamic behavior of large scale (1:55) undistorted models of TLP tendons were investigated. The tendons modeled were for a TLP designed to be deployed in a water depth of 914 m. The tendon motions were studied without the presence of the hull, In the study reported, the tendon models were subjected to three quite different design seas and the single and paired tendon configurations were compared under identical wave conditions. The main objective of this study was to examine the dynamic response of TLP tendons under controlled environmental conditions in order to better quantify the observed dynamic behavior. Underwater video tracking techniques were utilized in the experiments to obtain direct measurement of the inline and transverse displacements. Envelopes characterizing the extreme displacement behavior, spatial variations in response and collision behavior are presented and discussed.

  5. Mouse kidney transplantation: models of allograft rejection.

    PubMed

    Tse, George H; Hesketh, Emily E; Clay, Michael; Borthwick, Gary; Hughes, Jeremy; Marson, Lorna P

    2014-01-01

    Rejection of the transplanted kidney in humans is still a major cause of morbidity and mortality. The mouse model of renal transplantation closely replicates both the technical and pathological processes that occur in human renal transplantation. Although mouse models of allogeneic rejection in organs other than the kidney exist, and are more technically feasible, there is evidence that different organs elicit disparate rejection modes and dynamics, for instance the time course of rejection in cardiac and renal allograft differs significantly in certain strain combinations. This model is an attractive tool for many reasons despite its technical challenges. As inbred mouse strain haplotypes are well characterized it is possible to choose donor and recipient combinations to model acute allograft rejection by transplanting across MHC class I and II loci. Conversely by transplanting between strains with similar haplotypes a chronic process can be elicited were the allograft kidney develops interstitial fibrosis and tubular atrophy. We have modified the surgical technique to reduce operating time and improve ease of surgery, however a learning curve still needs to be overcome in order to faithfully replicate the model. This study will provide key points in the surgical procedure and aid the process of establishing this technique.

  6. Mouse Kidney Transplantation: Models of Allograft Rejection

    PubMed Central

    Clay, Michael; Borthwick, Gary; Hughes, Jeremy; Marson, Lorna P.

    2014-01-01

    Rejection of the transplanted kidney in humans is still a major cause of morbidity and mortality. The mouse model of renal transplantation closely replicates both the technical and pathological processes that occur in human renal transplantation. Although mouse models of allogeneic rejection in organs other than the kidney exist, and are more technically feasible, there is evidence that different organs elicit disparate rejection modes and dynamics, for instance the time course of rejection in cardiac and renal allograft differs significantly in certain strain combinations. This model is an attractive tool for many reasons despite its technical challenges. As inbred mouse strain haplotypes are well characterized it is possible to choose donor and recipient combinations to model acute allograft rejection by transplanting across MHC class I and II loci. Conversely by transplanting between strains with similar haplotypes a chronic process can be elicited were the allograft kidney develops interstitial fibrosis and tubular atrophy. We have modified the surgical technique to reduce operating time and improve ease of surgery, however a learning curve still needs to be overcome in order to faithfully replicate the model. This study will provide key points in the surgical procedure and aid the process of establishing this technique. PMID:25350513

  7. Use of a strontium-enriched calcium phosphate cement in accelerating the healing of soft-tissue tendon graft within the bone tunnel in a rabbit model of anterior cruciate ligament reconstruction.

    PubMed

    Kuang, G M; Yau, W P; Lu, W W; Chiu, K Y

    2013-07-01

    We investigated whether strontium-enriched calcium phosphate cement (Sr-CPC)-treated soft-tissue tendon graft results in accelerated healing within the bone tunnel in reconstruction of the anterior cruciate ligament (ACL). A total of 30 single-bundle ACL reconstructions using tendo Achillis allograft were performed in 15 rabbits. The graft on the tested limb was treated with Sr-CPC, whereas that on the contralateral limb was untreated and served as a control. At timepoints three, six, nine, 12 and 24 weeks after surgery, three animals were killed for histological examination. At six weeks, the graft-bone interface in the control group was filled in with fibrovascular tissue. However, the gap in the Sr-CPC group had already been completely filled in with new bone, and there was evidence of the early formation of Sharpey fibres. At 24 weeks, remodelling into a normal ACL-bone-like insertion was found in the Sr-CPC group. Coating of Sr-CPC on soft tissue tendon allograft leads to accelerated graft healing within the bone tunnel in a rabbit model of ACL reconstruction using Achilles tendon allograft.

  8. Extensor tendon injuries in athletes.

    PubMed

    Chauhan, Aakash; Jacobs, Bruce; Andoga, Alexandra; Baratz, Mark E

    2014-03-01

    Extensor tendon injuries of the hand and wrist in high-level athletes can cause a delay in return to play and permanently affect their performance. Given the inherent demand for a speedy and complete recovery, orthopedic surgeons must have an understanding of how to best direct an athlete's treatment for these injuries. The extensor anatomy is very intricate and a thorough understanding of the anatomy can help with both diagnosis and treatment. However, untreated or poorly managed injuries are at risk of leading to chronic deformities. We will discuss the diagnosis and management of the most common extensor tendon injuries and tendinopathies of the hand found in athletes: mallet fingers, swan-neck deformities, boutonniere deformities, central slip ruptures, sagittal band ruptures, intersection syndrome, extensor carpi ulnaris tendinitis, and extensor carpi ulnaris subluxation. PMID:24651290

  9. In vivo behavior of the human soleus muscle with increasing walking and running speeds.

    PubMed

    Lai, Adrian; Lichtwark, Glen A; Schache, Anthony G; Lin, Yi-Chung; Brown, Nicholas A T; Pandy, Marcus G

    2015-05-15

    The interaction between the muscle fascicle and tendon components of the human soleus (SO) muscle influences the capacity of the muscle to generate force and mechanical work during walking and running. In the present study, ultrasound-based measurements of in vivo SO muscle fascicle behavior were combined with an inverse dynamics analysis to investigate the interaction between the muscle fascicle and tendon components over a broad range of steady-state walking and running speeds: slow-paced walking (0.7 m/s) through to moderate-paced running (5.0 m/s). Irrespective of a change in locomotion mode (i.e., walking vs. running) or an increase in steady-state speed, SO muscle fascicles were found to exhibit minimal shortening compared with the muscle-tendon unit (MTU) throughout stance. During walking and running, the muscle fascicles contributed only 35 and 20% of the overall MTU length change and shortening velocity, respectively. Greater levels of muscle activity resulted in increasingly shorter SO muscle fascicles as locomotion speed increased, both of which facilitated greater tendon stretch and recoil. Thus the elastic tendon contributed the majority of the MTU length change during walking and running. When transitioning from walking to running near the preferred transition speed (2.0 m/s), greater, more economical ankle torque development is likely explained by the SO muscle fascicles shortening more slowly and operating on a more favorable portion (i.e., closer to the plateau) of the force-length curve.

  10. Ulnar Nerve Injury after Flexor Tendon Grafting.

    PubMed

    McCleave, Michael John

    2016-10-01

    A 43-year-old female is presented who underwent a two-stage tendon reconstruction and developed a low ulnar nerve palsy postoperatively. Exploration found that the tendon graft was passing through Guyon's canal and that the ulnar nerve was divided. This is a previously unreported complication. The reconstruction is discussed, the literature reviewed and a guide is given on how to identify the correct tissue plane when passing a tendon rod. PMID:27595967

  11. Tendon transfers for the drop foot.

    PubMed

    Schweitzer, Karl M; Jones, Carroll P

    2014-03-01

    The paralytic drop foot represents a challenging problem for even the most experienced orthopedic surgeon. Careful patient selection, thorough preoperative examination and planning, and application of tendon transfer biomechanical and physiologic principles outlined in this article can lead to successful results, either through a posterior tibialis tendon transfer, Bridle transfer, or variations on these procedures. Achilles lengthening or gastrocnemius recession may also be needed at the time of tendon transfer. PMID:24548510

  12. Management of complications of extensor tendon injuries.

    PubMed

    Lutz, Kristina; Pipicelli, Joey; Grewal, Ruby

    2015-05-01

    Treatment goals for the management of extensor tendon injuries include restoration of function, minimizing disability, and decreasing the risk of complications. These goals can be achieved with an accurate understanding of the zone-specific concerns for extensor tendon injuries, early referral to hand therapy, and active communication between hand surgeons and therapists. This article reviews extensor tendon injuries by zone, outlines optimal management strategies that help prevent complications, and describes the treatment of these complications. PMID:25934204

  13. Lubricin Surface Modification Improves Tendon Gliding After Tendon Repair in a Canine Model in Vitro

    PubMed Central

    Taguchi, Manabu; Sun, Yu-Long; Zhao, Chunfeng; Zobitz, Mark E.; Cha, Chung-Ja; Jay, Gregory D.; An, Kai-Nan; Amadio, Peter C.

    2011-01-01

    This study investigated the effects of lubricin on the gliding of repaired flexor digitorum profundus (FDP) tendons in vitro. Canine FDP tendons were completely lacerated, repaired with a modified Pennington technique, and treated with one of the following solutions: saline, carbodiimide derivatized gelatin/hyaluronic acid (cd-HA-gelatin), carbodiimide derivatized gelatin to which lubricin was added in a second step (cd-gelatin + lubricin), or carbodiimide derivatized gelatin/HA + lubricin (cd-HA-gelatin + lubricin). After treatment, gliding resistance was measured up to 1,000 cycles of simulated flexion/extension motion. The increase in average and peak gliding resistance in cd-HA-gelatin, cd-gelatin + lubricin, and cd-HA-gelatin + lubricin tendons was less than the control tendons after 1,000 cycles (p < 0.05). The increase in average gliding resistance of cd-HA-gelatin + lubricin treated tendons was also less than that of the cd-HA-gelatin treated tendons (p < 0.05). The surfaces of the repaired tendons and associated pulleys were assessed qualitatively with scanning electron microscopy and appeared smooth after 1,000 cycles of tendon motion for the cd-HA-gelatin, cd-gelatin + lubricin, and cd-HA-gelatin + lubricin treated tendons, while that of the saline control appeared roughened. These results suggest that tendon surface modification can improve tendon gliding ability, with a trend suggesting that lubricin fixed on the repaired tendon may provide additional improvement over that provided by HA and gelatin alone. PMID:18683890

  14. Outcome of quadriceps tendon repair.

    PubMed

    Puranik, Gururaj S; Faraj, Adnan

    2006-04-01

    Complete rupture of the quadriceps tendon is a well-described injury. There is a scarcity of literature relating to the outcome of patients with this injury after surgery. We undertook a retrospective analysis of patients who had surgical repair of their quadriceps tendon at our institution over a 13-year period, totalling 21 patients. Males were more commonly affected, with a male/female ratio of 4:1. The peak incidence was in the sixth decade of life. Assessment consisted of the completion of a functional knee questionnaire and a clinical examination. Symptomatic outcome following surgical repair was good with a mean symptom score generated of 19.16 out of a maximum of 25 using the Rougraff et al scoring system. Most of the patients returned to their pre-injury level of activity. Five degrees deficit and extension lag was present in three patients; these patients had the quadriceps repaired using transosseous sutures. Patients who had direct repair of the tendon using the Bunnell technique had lower Rougraff scores than the rest.

  15. The limitations of the tendon jerk as a marker of pathological stretch reflex activity in human spasticity.

    PubMed Central

    Fellows, S J; Ross, H F; Thilmann, A F

    1993-01-01

    The motor disorders associated with human spasticity arise, partly from a pathological increase in the excitability of muscle stretch reflexes. In clinical practice, reflex excitability is commonly assessed by grading the reflex response to a blow delivered to the tendon of a muscle. This is a much simpler response than the complex patterns of activity which may be elicited following muscle stretch caused by active or passive movement. Changes in the biceps brachii tendon jerk response have been followed over the first year after stroke in a group of hemiparetic patients and compared with changes in short and medium latency reflex responses elicited by imposed elbow flexion of initially relaxed spastic muscle and with the development of the late reflex responses which contribute to spastic hypertonia. A progressive increase in tendon jerk responses occurred over the first year following stroke, whereas reflex responses to imposed displacement, in particular the late reflex responses contributing to muscle hypertonia, reached their peak excitability one to three months after stroke, with a subsequent reduction in activity. The tendon jerk reflex therefore provides an incomplete picture of the pathological changes in the reflex responses in spasticity. PMID:8505646

  16. Biomechanical analysis of subjective pinching effort based on tendon-skeletal model.

    PubMed

    Kurita, Yuichi; Onoue, Takehiro; Ikeda, Atsutoshi; Ogasawara, Tsukasa

    2009-01-01

    In this paper, the influence of the finger posture on the subjective effort during pinching motion is investigated by using a tendon-skeletal finger model. The experimental results show that the subjective effort human feels is affected by the size of the object he/she pinches, and the subjective effort correlates with the finger length. The simulation results show that the pattern of the tendon forces is similar to that of the EMG activity measured in the experiment, and the positive correlation was observed between the finger length and the object size where the summation of the tendon forces becomes the minimum. These results suggest that the reason why subjective pinching effort is influenced by the finger posture is the difference in the efficiency of the force transmission from the muscles.

  17. Arthroscopic debridement for bilateral calcific tendinitis of the subscapularis tendons: a case report.

    PubMed

    Tung, Kam-Lung; Woo, Siu-Bon

    2015-04-01

    We report on a 36-year-old man who underwent arthroscopic debridement for bilateral calcific tendinitis of the subscapularis tendons. The patient had a positive coracoid impingement test for both shoulders. Radiology showed calcific deposits at the insertion of both subscapularis tendons, close to the lesser tuberosities and just posterior to the coracoid tips. The patient underwent sequential arthroscopic coracoplasty and removal of calcific deposits in the subscapularis tendons. The patient returned to work 6 weeks after each surgery. At 2 years, the patient had no shoulder pain, with full range of motion and full power of the subscapularis muscles. The coracoid impingement test was negative for both shoulders. There was no evidence of recurrence.

  18. High axial load termination for TLP tendons

    SciTech Connect

    Salama, M.M.

    1992-03-03

    This patent describes a hollow high axial load termination for a composite tubular tendon. It comprises: a curved hollow termination body open at one end wit a circular opening and connected at the opposite curved end with an elongated hollow member of lesser diameter than the diameter of the circular opening of the termination body, a composite tubular tendon containing axial fibers and helical fibers laid on an inner hollow liner; fibers of the composite tubular tendon extending over and covering the termination body from the abutment with the composite tubular tendon to the elongated member of lesser diameter than the termination body.

  19. PTH promotes allograft integration in a calvarial bone defect

    PubMed Central

    Sheyn, Dmitriy; Yakubovich, Doron Cohn; Kallai, Ilan; Su, Susan; Da, Xiaoyu; Pelled, Gadi; Tawackoli, Wafa; Cook-Weins, Galen; Schwarz, Edward M.; Gazit, Dan; Gazit, Zulma

    2013-01-01

    Allografts may be useful in craniofacial bone repair, although they often fail to integrate with the host bone. We hypothesized that intermittent administration of parathyroid hormone (PTH) would enhance mesenchymal stem cell recruitment and differentiation, resulting in allograft osseointegration in cranial membranous bones. Calvarial bone defects were created in transgenic mice, in which luciferase is expressed under the control of the osteocalcin promoter. The mice were given implants of allografts with or without daily PTH treatment. Bioluminescence imaging (BLI) was performed to monitor host osteprogenitor differentiation at the implantation site. Bone formation was evaluated with the aid of fluorescence imaging (FLI) and micro–computed tomography (μCT) as well as histological analyses. Reverse transcription polymerase chain reaction (RT-PCR) was performed to evaluate the expression of key osteogenic and angiogenic genes. Osteoprogenitor differentiation, as detected by BLI, in mice treated with an allograft implant and PTH was over 2-fold higher than those in mice treated with an allograft implant without PTH. FLI also demonstrated that the bone mineralization process in PTH-treated allografts was significantly higher than that in untreated allografts. The μCT scans revealed a significant increase in bone formation in Allograft + PTH–treated mice comparing to Allograft + PBS treated mice. The osteogenic genes osteocalcin (Oc/Bglap) and integrin binding sialoprotein (Ibsp) were upregulated in the Allograft + PTH–treated animals. In summary, PTH treatment enhances osteoprogenitor differentiation and augments bone formation around structural allografts. The precise mechanism is not clear, but we show that infiltration pattern of mast cells, associated with the formation of fibrotic tissue, in the defect site is significantly affected by the PTH treatment. PMID:24131143

  20. Potential mechanisms of a periosteum patch as an effective and favourable approach to enhance tendon-bone healing in the human body.

    PubMed

    Li, Hong; Jiang, Jia; Wu, Yang; Chen, Shiyi

    2012-03-01

    Tendon-bone healing is a progressive and complex pathophysiological process after tendon graft transplantation into a bone tunnel. A fibrous scar tissue layer forms at the graft-bone interface, which means a weak bonding of the graft in the bone tunnel. Periosteum, a favourable autologous tissue, was confirmed to be effective in promoting tendon-bone healing in the human body. The advantages of a periosteum patch for