Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “LIGAMENTS”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 1,603 records · Page 89Linked to original sources
PubMed1999

Collagen fibril diameter distributions in rabbit anterior cruciate and medial collateral ligaments: changes with maturation.

This study presents morphometric analyses of the collagen fibril diameters of rabbit anterior cruciate and medial collateral knee ligaments of New Zealand White rabbits (young, age two months and adult, age thirty-six to forty months). Measurements were made from transmission electron micrographs of transverse ligament sections of approximately 50,000x magnification. Statistically significant differences in the mean fibril diameters were found between the anterior cruciate and medial collateral ligaments of the thirty-six to forty month old animals (.069 +/- .005, .092 +/- .016 mm, p < .1); however, no statistical significance was found for differences between these ligaments in two month old animals (.077 +/- .006, .082 +/- .009, p > .1). These data support the idea that known differences in fibril distributions of adult rabbit anterior cruciate and medial collateral ligaments develop with maturation, and may reflect both the cellular environment in which the fibrocytes of these ligaments are subject to, as well as the developmental genetic program of these cell populations.

Animals↗
PubMed2002

[Arthroscopic reconstruction of the anterior cruciate ligament using double anteromedial and posterolateral bundles].

We propose a method for repairing the anterior cruciate ligament which takes advantage of the multifascular nature of the ligament to achieve better physiological anteroposterior and rotational stability compared with conventional methods. Arthroscopic reconstruction of the anteromedial and posterolateral bundles of the ligament closely reproduces normal anatomy. We have used this technique in 92 patients with anterior cruciate ligament laxity and present here the mid-term results. The hamstring tendons (gracilis and semitendinosus) are harvested carefully to obtain good quality grafts. Arthroscopic preparation of the notch allows careful cleaning of the axial aspect of the lateral condyle; it is crucial to well visualize the region over the top and delimit the 9 h-12 h zone for the right knee or the 12-15 h zone for the left knee. The femoral end of the anteromedial tunnel lies close to the floor of the intercondylar notch, 5 to 10 mm in front of the posterior border of the lateral condyle, at 13 h for the left knee and 11 h for the right knee. The femoral end of the posterolateral tunnel lies more anteriorly, at 14 h for the left knee and 10 h for the right knee. The tibial end of the posterolateral tunnel faces the anterolateral spike of the tibia. The tibial end of the anteromedial tunnel lies in front of the apex of the two tibial spikes half way between the anteromedial spike and the anterolateral spike, 8 mm in front of the protrusion of the posteriolateral pin. The posterolateral graft is run through the femoral and tibial tunnels first. A cortical fixation is used for the femoral end. The femoral end of the anteromedial graft is then fixed in the same way. The tibial fixation begins with the posterolateral graft with the knee close to full extension. The anteromedial graft is fixed with the knee in 90 degrees flexion. Thirty patients were reviewed at least six months after the procedure. Mean age was 28.2 years. Mean overall IKDC score was 86% (36% A and 50% B). Gain in laxity was significant: 6.53 preoperatively and 2.1 postoperatively. Most of the patients (86.6%) were able to resume their former occupation 2 months after the procedure. The different components of the anterior cruciate ligament and their respective functions have been the object of several studies. The anteromedial bundle maintains joint stability during extension and anteroposterior stability during flexion. The posterolateral bundle contributes to the action of the anteromedial bundle with an additional effect due to its position: rotational stability during flexion. In light of the multifascicular nature of the anterior cruciate ligament and the residual rotational laxity observed after conventional repair, our proposed method provides a more anatomic reconstruction which achieves better correction of anteroposterior and rotational stability. This technique should be validated with comparative trials against currently employed methods.

Adult↗
PubMed2004

Bone-demineralized bone-bone graft for ligament reconstruction in rats.

Bone-tendon-bone (B-T-B) type grafts were prepared for ligament reconstruction by harvesting the radius from rats, wrapping both ends of each bone with a laboratory film leaving only the central 10 mm exposed, and demineralizing the central part by immersing the bone in 1.75% HCl solution. In the grafts prepared, the central part of the bone became semi-translucent and flexible while the ends remained as hard bone tissue, thus forming a B-T-B type graft. The tensile strength of the grafts was greater than that of the medial collateral ligaments of the rats and about the same as of their anterior cruciate ligaments. No inflammation or other adverse reaction was noticed in experimental subcutaneous transplantation and the grafts showed excellent biocompatibility. In experimental ligament reconstruction, the test animals did not show any impairment on gait. There was invasion of fibroblasts into the graft at 4 weeks, and the fibroblasts were found through the whole graft and what looked like ligament tissue could be seen macroscopically at 8 weeks. Besides, bone tissue had infiltrated into the inside cavity of the non-demineralized part of the graft and proliferation, resulting in good bone union. The results obtained suggest that the grafts prepared in this study have a sufficient potential as B-T-B type grafts for ligament reconstruction.

Animals↗
PubMed2005

The symmetry of the medial collateral and anterior cruciate ligament properties: a biochemical study in the rat hind limb.

The medial collateral (MCL) and the anterior cruciate ligament (ACL) of the rat's knee are frequently used in biomedical research and occasionally in ligament healing studies. The contralateral normal ligament serves as a control. In this study the presence of symmetry in the biomechanical properties of the MCL and the ACL was investigated. Bilateral femur-MCL-tibia and femur-ACL-tibia preparations were obtained from the hind limbs of sixty rats and were subjected to tensile testing to failure under the same loading conditions. Tensile load to failure, stiffness and energy absorption capacity were measured and the mode of failure was recorded. All biomechanical parameters were not significantly different between the two knees of the same animal, although significant individual variation was evident. The most common mechanism of failure was mid-substance tear. Symmetry seems to exist in the biomechanical properties of the MCL and the ACL in the rat knee. When ligament healing is evaluated, increased group size is necessary and the use of a normal control group may be advisable. The contralateral normal knee ligament may serve as a control when the properties of an injured ligament are evaluated and when the parameters of tensile testing failure under similar load conditions are applied.

Animals↗
PubMedDate not supplied

Advances in anterior cruciate ligament surgery.

The anterior cruciate ligament is the most frequently torn ligament in the knee. Diagnosis of cruciate ligament tears is often a difficult task. Tests typically used in diagnosis are the anterior drawer test, Lachman's test, pivot shift test, and the flexion rotation drawer. Arthroscopy has increasingly become the standard for the diagnosis of anterior cruciate ligament tears. Management of these tears has been controversial. The diagnostic techniques are discussed and a surgical technique is described for anterior cruciate ligament reconstruction as an outpatient procedure. The middle one-third of the patellar tendon is used as a graft, harvested subcutaneously, and fixed with interference fit screws. The postoperative function of anterior cruciate ligament deficient knees has been quite satisfactory. Morbidity is decreased relative to open surgical inpatient procedures. Finally, overall cost to the patient has been significantly reduced.

Anterior Cruciate Ligament↗
PubMed1993

[Technical, material and biomechanical requirements for alloplastic replacement of the anterior cruciate ligament surgical technic].

Chronically instable knee-joints progressively draw to an arthrosis as a result of the irregular kinematic. Different operative techniques to replace the anterior cruciate ligament using exclusively autologous, homologous or heterologous grafts in all cases of chronic instabilities, but the primary sole suture of acute ACL injuries, too, didn't show long-term stable results in many cases. Recurrent ruptures were found first of all at the intraarticular edge of the femoral tunnel caused by permanent abrasions of the replacement. The reason why is the large angle of the ACL and each replacement respectively under motion. The question of what tissue could or should be used for renewed autogenous reconstructions in case of re-instabilities and after using bone-tendon-bone-mid-third patellar-tendon-grafts isn't yet been discussed to the end. Because of the fact that there is no isometric behaviour of the complete ACL but of a few fibres only depending on the position of the knee the complete reconstruction of the ACL is absolutely impossible, but only a partial substitute. The anatomically limited intraarticular joint-space (notch) confines the replacements in their dimension and endangers voluminous reconstructions by an impending impingement especially as a result of the immediately postoperative swelling of the transplants. The use of the mid-third-patellar-tendon-graft destroys a lot of proprioceptors and causes a partly loss of the neuromuscular balance previously impaired by the loss of the ACL including its receptors. In addition to this the still existing proprioceptors of the ligamentous stumps can be definitively destroyed by big tunnels. Each autologous graft passes a long-term transformation and at best achieves to 50% of the maximum stress capacity of an original ACL after two years. Resulting from these reasons synthetic and unlimited-ly available ligaments presented themselves to be used for ACL replacements. The Trevira-ligament of polyethylenetherephthalat (= TRE-VIRA HOCHFEST 730R) seems to be best qualified therefore at the present. It meets the material and technical requirements and makes allowance for all biomechanical knowledge. A modified over-the-top technique by arthroscopy or mini-arthrotomy (minimized operative trauma) enables the preservation of still existing ligamentous tissue on the one hand and guarantees the immediate postoperative functional therapy on the other hand. A recurrent instability independent of cause doesn't bring about a worse starting position for the following renewed stabilization and enables corrective operative techniques including the substitute of a ruptured synthetic ligament if required.

Anterior Cruciate Ligament↗
PubMed1996

Accuracy of direct signs of tears of the anterior cruciate ligament.

OBJECTIVE: To evaluate the accuracy of direct magnetic resonance imaging (MRI) signs of tears of the anterior cruciate ligament. PATIENTS AND METHODS: Over the period April 1991 to February 1994, 92 consecutive MRI studies of the knee were obtained for which arthroscopic data were also available. The MRI studies were retrospectively evaluated for course, continuity, signal intensity, morphologic features, contour and visualization of the anterior cruciate ligament. Arthroscopic findings were correlated with individual primary signs and the overall MRI diagnosis. RESULTS: Among the cases studied were 4 partial and 32 complete tears of the anterior cruciate ligament (as determined by arthroscopy). Because of the low number of partial tears, it was not possible to draw any meaningful conclusions about the MRI diagnosis of this type of tear. For complete tears, the criteria with the highest accuracy were abnormal course of the ligament (96.0%) and high signal intensity (89.3%). The overall diagnostic accuracy of MRI was 98.8%. CONCLUSIONS: The most accurate direct MRI finding in patients with a complete tear of the anterior cruciate ligament was abnormal course of the ligament, followed by abnormally high signal intensity.

Adolescent↗
PubMed2005

Arthroscopic fixation of avulsion of the posterior cruciate ligament from femoral insertion.

Femoral avulsion of the posterior cruciate ligament (PCL) is not common, especially in adults. We present a case and an arthroscopic repair technique using 4 transfemoral tunnels; 2 anterior tunnels for fixation of the anterior bundle of the PCL and 2 posterior for the posterior bundle. Our case was that of a femoral avulsion of the PCL associated with tibial avulsion of the anterior cruciate ligament and femoral avulsion of the medial collateral ligament of the left knee in an adult. We repaired the tibial avulsion of anterior cruciate ligament using an arthroscopic transtibial suture technique and the femoral avulsion of the medial collateral ligament by using staple fixation.

Accidents, Traffic↗
PubMed2006

Conservative and postoperative rehabilitation of isolated and combined injuries of the medial collateral ligament.

Injuries to the medial collateral ligament (MCL) are very common and there seems to be a consensus supporting the conservative management of grade I and II tears. Grade III tears are also usually treated conservatively unless associated with injuries to the anterior cruciate ligament or posterior cruciate ligament. This article outlines rehabilitation programs for conservative treatment of MCL injuries, and postoperative programs after anterior cruciate ligament or multiple ligament reconstruction. In addition, the use of functional and prophylactic bracing for injuries of the MCL is reviewed.

Anterior Cruciate Ligament Injuries↗
PubMedDate not supplied

[Which knee ligaments must be reconstructed in anterior and posterior valgus and varus instability? An experimental study].

This study aims to localize the ligamentous lesions in distinct knee joint instabilities. For that reason 41 human cadaver knee joint specimens were tested in a three-dimensional determined apparatus. Ligaments were successively dissected and forces and torques were introduced. Both cruciates are the dominant structures in preventing straight anterior und posterior movement of the tibia. As a supporting element the postero-medial capsule prevents anterior dislocation in ACL-deficient knees. Therefore extraarticular procedures in cruciate instabilities will not be successful. In contrast varus- and valgus instabilities resulted after transsection of a couple of ligaments. Valgus stability decreased after cutting the medial collateral, posterior oblique and both cruciate ligaments. The most important element in preventing straight varus instability was the lateral collateral followed by the posterior cruciate ligament, while the popliteus tendon had only little influence. Therefore in medial and lateral instabilities all supporting structures should be exposed and reconstructed.

Anterior Cruciate Ligament↗
PubMed1979

The role of Whitnall's ligament in ptosis surgery.

Whitnall's ligament has been described functionally as a check ligament of the levator. Our anatomic dissections and operative findings indicate that this ligament is primarily a support for the upper eyelid and superior orbit. Whitnall's ligament is frequently confused with the levator horns and is unfortunately cut during many ptosis procedures. This is to be avoided because much larger levator resections are required when this ligament's support to the upper lid and the fulcrum effect for the levator are lost. Preserving and enhancing the function of Whitnall's ligament improves the efficiency of the levator, making large levator resections rarely necessary. We have noted no more lid lag than that seen with other forms of levator surgery.

Blepharoptosis↗
PubMed1998

Comparison of biomechanical properties of the incisor periodontal ligament among different species.

BACKGROUND: The aim of this study was to obtain a more precise understanding of the mechanical properties of the periodontal ligament in continuously erupting incisors by comparing the shear stress-strain relations among teeth from four closely related species. METHODS: Four species of experimental animals (mice, hamsters, rats, and rabbits) were used. Transverse sections of the left mandibular incisors were cut from the incisal, middle, and basal regions of each incisor. The tooth was pushed out of the alveolar bone in an extrusive direction at 5 mm/min using a materials testing machine. The maximum shear stress, maximum shear strain, tangent modulus, and failure strain energy density were estimated from the resulting stress-strain curve. Polarized light microscopic observations of collagen fibers were also made. RESULTS: All the biomechanical measures tended to decrease from the incisal toward the basal regions in all species. There were large species differences, especially in the incisal region, with the greatest maximum shear stress and failure strain energy density in hamsters. The greatest tangent modulus and the smallest maximum shear strain were observed in mice. The birefringent fiber architectures of the periodontal ligaments in the four species appeared to be similarly organized; the incisal periodontal ligament appeared to have more organized and thicker collagen fibres than did the middle and basal ligaments in the four species. CONCLUSIONS: These results suggest that the regional differences in the biomechanical properties of the periodontal ligament depend upon the developmental stages of the periodontal collagen fibers that may be related to the general arrangement, diameters, and densities of the collagen fiber bundles and the fiber insertions into the alveolar bone and cementum. The species differences in the biomechanical properties may be due to differences in the width of the periodontal ligament and the waviness as well as the strength and stiffness of the periodontal collagen fibers.

Animals↗
PubMed1998

Suspensory ligament of Berry: its relationship to recurrent laryngeal nerve and anatomic examination of 24 autopsies.

BACKGROUND: It is important to clarify the relationship between the recurrent laryngeal nerve (RLN) and the ligament of Berry to prevent damage to the RLN in thyroid surgery. The purpose of the present paper is to identify this relationship to prevent surgical complications. METHODS: Among the 486 thyroid surgery cases, 689 RLNs were identified and their course detected. Topography of the laryngotracheoesophageal region and the histology of the ligament of Berry were studied in detail in 25 autopsied cadavers. RESULTS: All nerves identified by surgery and autopsy were located laterodorsally to the ligament of Berry. They were clearly separated, and no nerve penetrated the ligament nor was medially located to it. The ligament of Berry strongly connected the thyroid gland to the trachea and was identified as a whitish connective tissue band. No paralysis of the RLN occurred during identification of the nerve during surgery. CONCLUSIONS: It was confirmed that the RLN never penetrates the ligament of Berry but is located laterally to it. From these topographic findings, no injury to the RLN will occur from a separation close to the goiter in thyroid surgery.

Adult↗
PubMed1990

Effect of altered occlusal function on transseptal ligament and new bone thicknesses in the periodontium of the rat.

Alteration of tooth function is assumed to change stress/strain on the adjacent alveolar bone and its mucoperiosteum, producing changes in morphology similar to those described for other load-bearing bones. The present study suggested that crestal alveolar bone and its mucoperiosteum respond differently to stress/strain than load-bearing bones in other locations, possibly due to differences in the mechanism of bone loading by muscles and teeth. Occlusal hypofunction was initiated by extraction of agonist teeth; the contralateral teeth were placed in hyperfunction by the surgery. Untreated animals were also studied. 3H-proline was injected, animals were killed 1-5 weeks later, and the thicknesses of new bone and transseptal ligament were measured. After 5 weeks of altered function, total thickness (new bone + transseptal ligament) was similar in untreated and in hypofunctional and hyperfunctional situations; however, a new ratio between transseptal ligament and new bone thicknesses was established. Occlusal force was negatively correlated with new bone and positively correlated with transseptal ligament thickness; both thicknesses were statistically correlated in each functional situation (P less than 0.001). Hyperfunction resulted in increased transseptal ligament thickness, but decreased new bone thickness as compared to untreated controls (P less than 0.001). In contrast, hypofunction resulted in an increased new bone thickness, but a decreased transseptal ligament thickness (P less than 0.001). Tissue responses assure appropriate support for the teeth in each functional situation.

Alveolar Process↗
PubMed1976

The ligaments of the human wrist and their functional significance.

The ligamentous anatomy of the wrist was analyzed by studying (1) 28 dissected human wrists, (2) and by examination of 19 wrist injuries created mechanically. Six volar intracapsular ligaments are described, two stabilizing the distal carpal row, three stabilizing the proximal carpal row and one stabilizing the proximal scaphoid pole. More specific terminology for these ligaments is proposed. An explanation of how these ligaments participate in the mechanical functioning of the carpus is advanced. Mechanically created wrist injuries had ruptures of specific ligaments as described augmenting a need for a more specific terminology. Suspected mechanisms of injury in perilunate and lunate dislocations are mentioned based upon the functional understanding of the intracapsular ligaments.

Adult↗
PubMed1979

Unipolarity of fibroblasts in rodent periodontal ligament.

In order to investigate whether fibroblasts in rodent periodontal ligament have a structural polarity, the position of the Golgi apparatus or the centriolar region in the cells was studied using light and electron microscopy. It appeared that, in the periodontal ligament of continuously erupting mouse and rat incisors, centrioles in fibroblasts on the tooth side of the ligament are preferably located in the anterior (occlusally directed) part of the cytoplasm. Polarity of fibroblasts in a single direction was less pronounced or absent on the bone side of the tissue. In the mouse, fibroblasts in the connective tissue adjacent to the incisor also contained an extensive system of cytoplasmic microtubules, whereas in the fibroblasts on the bone side of the ligament microtubules were less frequent. Unipolarity of fibroblasts was also observed in the periodontal ligament of the rat maxillary first molar, which is characterized by a limited eruption. Here, the Golgi region was usually situated in that pole of the cells that was directed towards the alveolar wall and the occlusal plane. It is suggested that structural polarity of fibroblasts in the periodontal ligament of rodent teeth is associated with orientation of functional activities of the cells, such as unidirectional movement or unidirectional deposition or phagocytosis of collagen.

Animals↗
PubMed1985

Partial denervation of the ovaries by transection of the suspensory ligament does not inhibit ovulation in rats treated with pregnant mare serum gonadotropin.

Adrenergic nerves reach the ovary via two routes: along the arteries to the ovary and via the suspensory ligament. Results from earlier investigations suggest that denervation of the nerves along the arteries does not influence the ovulatory process. In the present study we have examined whether denervation by transection of the ovarian suspensory ligament influences the ovulatory process. Partial denervation of the ovary by transection of the ovarian suspensory ligament, sham operation, or only anesthesia were performed on immature 25-day-old rats. To induce ovulation, pregnant mare serum gonadotropin (PMSG) was injected in the morning (0800-0930), when the rats were 26 days old. This PMSG treatment normally induces ovulation around 0200 in the early morning of day 29 with subsequent formation of corpora lutea. Rats were killed 5-8 hr, 3 days, and 5 days after this ovulation time. Ovarian interstitial norepinephrine levels were markedly decreased after transection of the suspensory ligament. Ovulations had occurred in all denervated, as well as sham-operated, and control rats. The various groups did not differ in the number of ovulations per rat. Thus, the adrenergic nerves in the suspensory ligament appear not to be necessary for ovulation. Whether catecholamines themselves play a role in the ovulatory process cannot be elucidated from this experiment, since the norepinephrine content in the ovary was not totally depleted. It seems unlikely that adrenergic nerves reach the corpus luteum via the suspensory ligament, since transection of this structure did not change the luteal content of norepinephrine.

Animals↗
PubMed2004

Skin ligaments: regional distribution and variation in morphology.

Skin ligaments (SL) (L. retinacula cutis) are present extensively in the face, hands, feet, and in breast tissue, but have seldom been reported elsewhere in the body. The traditional histological view of the subcutaneous region is that it comprises a matrix of loose connective tissue devoid of fibrous specializations. The purpose of this study was to determine the structure and distribution of skin ligaments. Eight embalmed cadavers (3 males, 5 females, 69-90 years of age) were used in this study. Tissue was prepared using the E12 plastination technique. Macroscopic and microscopic examination demonstrated the widespread presence in the limbs and most of the rest of the body of fibrous strands linking the base of the dermis and the superficial fibers of the underlying deep fascia. The morphology and distribution of these skin ligaments were similar in the individuals examined. Variations in the structure of the skin ligaments depended on the presence of underlying muscle, neurovascular bundles, intermuscular septa and adipose tissue. We conclude that skin ligaments are complex fibrous structures that are present over most of the body. They form an extensive peripheral network in the subcutaneous fat. These 'ligaments' seem to provide an anchorage of skin to deep fascia that is flexible and yet resistant to mechanical loading from multi-directional forces. The use of the E12 plastination technique coupled with fluorescent confocal microscopy has been of benefit in visualizing and delineating SLs from other soft tissue structures in three planes.

Aged↗