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At least 1,207 records · Page 67Linked to original sources
PubMed2003

[Carpal instability with scapho-lunate dissociation treated using the flexor carpi radialis and scaphoid-trapezoid ligament repair: foundations, technique and results of preliminary series].

Carpal instability with scapho-lunate dissociation is still attributed to rupture of the so-called scapho-lunate ligament. Actually, this structure is not a ligament but a loose capsule allowing very different flexion of the scaphoid (92 degrees) and the lunate (20 degrees). As reconstruction of the scapho-lunate "ligament" has often been less than satisfactory we searched for another technique. Sections of the scapho-lunate "ligament" on cadaver specimens never produce scapho-lunate dissociation. This dissociation can not occur because the scaphoid is maintained in the radial facette. It was observed that the only way to produce scapho-lunate dissociation is to section the scapho-trapezo-trapezoid ligament allowing flexion of the scaphoid and dorsal dislocation out of the radial facette. The scapho-trapezo-trapezoid ligament is not well known and is not described in anatomy text books because it is hidden by the flexor carpi radialis tendon. It is confluent with the scaphoid and the trapezoid. This produces a radial (scapho-trapezoid) column which acts like a true external pillar maintaining the height of the carpus and preventing carpal collapse. Finally, dissociation of the proximal pole from the semi-lunate can only occur by posterior displacement. After experimenting the technique on cadaver specimens, we developed a reconstruction method for the palmar scapho-trapezoid ligament using a band of the flexor carpi radialis tendon, applied in 38 patients. The flexor carpi radialis band measured 7 cm and was left attached to the base of the second metacarpal then passed in a tunnel bored anteriorly to posteriorly in the distal pole of the scaphoid. The band was then drawn dorsally while maintaining the scaphoid in place, and sutured to the postero-ulnar border of the radius. The height of the carpus was restored as was scaphoid movement over the lunate. The reduction persisted at mid- and long-term and prevented carpal collapse and joint destruction. Among the 38 operated patients, 33 remained pain free and 5 complained of minor pain under stressful conditions. All were satisfied. Anatomic research and clinical experience has demonstrated that the scapho-trapezoidal ligament is the key to scapho-lunate dissociation and its correction. Currently, this operation is the only way to achieve easy and persistent correction of carpal instability with scapho-lunate dissociation.

Biomechanical Phenomena↗
PubMed1992

The effect of functional knee-braces on strain on the anterior cruciate ligament in vivo.

Functional knee-braces are widely used to protect injured or reconstructed anterior cruciate ligaments, despite the fact that few scientific data support their efficacy. We studied seven functional braces, representative of both the typical custom-fit and off-the-shelf designs. The braces were tested on subjects who had a normal anterior cruciate ligament and were scheduled for arthroscopic meniscectomy or exploration of the knee under local anesthesia. After the operative procedure, a Hall-effect strain-transducer was applied to the anterior cruciate ligament. Under low anterior shear loads, two braces provided some protective strain-shielding effect compared with no brace, but this strain-shielding effect did not occur at the higher anterior shear loads expected during the high-stress activities common to athletic events. The DonJoy, Townsend, C.Ti., and Lenox Hill braces demonstrated a strain-shielding effect on the anterior cruciate ligament with an internal torque of five newton-meters applied to the tibia. None of the braces had any effect on strain on the anterior cruciate ligament during active range of motion of the knee from 10 to 120 degrees or during isometric contraction of the quadriceps. Wearing of a brace did not produce an increase in the value for strain on the anterior cruciate ligament. For the activities that were evaluated in this study, none of the braces produced adverse effects on the anterior cruciate ligament, and there were no significant differences in the strain on the anterior cruciate ligament between the use of a custom-fit or an off-the-shelf brace design. There were no apparent advantages of the more expensive custom-made braces compared with the off-the-shelf designs.

Adult↗
PubMedDate not supplied

[Treatment problems in old and recent rupture of the lateral knee ligament].

The authors have treated 31 fresh ruptures of the lateral ligament and 104 cases of chronic instability of the lateral side of the knee. In recent ruptures the results obtained after surgical repair were not as gratifying as those obtained after injuries of the medial ligament. The cases operated upon were tears of the lateral ligament associated with ruptures of one or both cruciate ligaments. The frequency of rupture of the popliteus tendon is emphasized. The authors recommend, when necessary, a double surgical approach both laterally and posteriorly and plaster cast immobilization for more than 6 weeks. Tendon transfer in recent lesions have been done when suture of a cruciate ligament was impossible. The results of several procedures for chronic instability were analysed; transposition of the patellar ligament, transposition of the head of the fibula, or tightening of the lateral structures of the knee (capsule, ligament, popliteus tendon). Associated lesions of the cruciate ligament were treated by tendon transfer. Poor results were obtained in those presenting with fixed varus deformities. The authors conclude that such deformities should be corrected by osteotomy.

Adolescent↗
PubMed2004

Effects of Shuanghuangbu on the total protein content and ultrastructure in cultured human periodontal ligament cells.

BACKGROUND: Successful periodontal regeneration depends on the migration, proliferation and differentiation of periodontal ligament cells in periodontal defects. The total protein content and the ultrastructure demonstrate the metabolizability and activity of periodontal ligament cells. This study was conducted to observe the effects of Shuanghuangbu, a mixture of medicinal herbs, on the total protein content and the ultrastructure of human periodontal ligament cells. METHODS: Periodontal ligament cells were grown to confluence and then cultured in Dulbecco's modified eagle medium (DMEM) supplemented with Shuanghuangbu over the concentration range of 0 to 1000 microg/ml. The total protein content in cultured cells was determined by using Coommasie brilliant blue technique. Periodontal ligament cells were incubated in 0 and 100 microg/ml Shuanghuangbu decoction for 5 days, then observed through transmission electron microscope. RESULTS: The total protein content of human periodontal ligament cells increased in each experiment group added 10 - 1000 microg/ml Shuanghuangbu respectively, and the effect of 100 microg/ml was excellent. Under the transmission electron microscope, there were more rough endoplasmic reticulums and mitochodrias in the experiment group than those in the control group. CONCLUSION: Shuanghuangbu stimulates the protein synthesis of human periodontal ligament cells and improves human periodontal ligament cells' metabolizability and activity.

Cells, Cultured↗
PubMed2004

Ligament structure, physiology and function.

Ligaments are specialized connective tissues with very interesting biomechanical properties. They have the ability to adapt to the complex functions that each are required to perform. While ligaments were once thought to be inert, they are in fact responsive to many local and systemic factors that influence their function within the organism. Injury to a ligament results in a drastic change in its structure and physiology and creates a situation where ligament function is restored by the formation of scar tissue that is biologically and biomechanically inferior to the tissue it replaces. This article will briefly review the basic structure, physiology and function of normal versus healing knee ligaments, referring specifically to what is known about two of the most extensively studied and clinically relevant knee ligaments, the anterior cruciate (ACL) and medial collateral (MCL) ligaments of the knee. Those readers wishing for more comprehensive sources of information on ligament biology and biomechanics are referred to many excellent reviews on these topics.

Biomechanical Phenomena↗
PubMed2005

Wrist ligaments: their significance in carpal instability.

BACKGROUND: Understanding the exact contribution of the supporting ligaments to the functional integrity of the wrist is crucial for the diagnosis and treatment of carpal instabilities. The present study evaluates functional significance of the wrist ligaments with respect to carpal instabilities. MATERIALS AND METHODS: Sixteen fresh cadaver wrists were dissected. Extrinsic and intrinsic ligaments of the wrists (ligamentum radioscaphocapitatum, ligamentum radiolunotriquetrum and ligamentum triquetrohamatocapitatum) were sectioned sequentially. After sectioning of each ligament, the wrist was examined for clinical signs of instability such as misalignement of carpal bones, limited range of motion and dorsal translation. When instability was suspected, radiographs were taken and if instability was confirmed, then the ligament was repaired. RESULTS: Although none of the dorsal ligaments sectioning resulted in instability, sectioning of ligamentum scaphotrapeziotrapezoideum, ligamentum radioscaphocapitatum, ligamentum radiolunotriquetrum and ligamentum triquetrohamatocapitatum displayed scaphotrapeziotrapezoidal, dorsal intercalated segment, lunotriquetral and capitohamate instability respectively. In two wrists with arthrosis, sectioning of all ligaments didn't lead to any instability. CONCLUSION: Instability of the wrist can be classified on anatomical basis after the name of these four ligaments involved i.e. l. scaphotrapeziotrapezoideum, l. radioscaphocapitatum, l. radiolunotriquetrum and l. triquetrohamatocapitatum respectively . This approach clarifies the etiology and treatment of carpal instabilities.

Cadaver↗
PubMed2006

The morphology and function of the quadrate ligament.

There is a paucity of information in the literature regarding the quadrate ligament and the information that does exist is extremely conflicting. We dissected 30 cadavers (60 sides) to determine the morphology and function of this enigmatic ligament. A quadrate ligament (thickening of the elbow joint capsule) was found in all specimens. In all specimens this band was distinct from the circumferential fibres of the annular ligament. The length, width, and thickness of the quadrate ligament were found to be 11 mm, 8 mm, and 1 mm respectively. This ligament not only aided in securing the neck of the radius to the ulna but also resisted excessive supination and, to a lesser degree, pronation of the forearm. Following transection of the quadrate ligament, the head of the radius was secured to the ulna considerably less firmly and supination and pronation increased by 10 to 20 degrees and 5 to 8 degrees respectively. The quadrate ligament contributes to proximal radioulnar stability, limits the "spin" of this joint, and should be considered in manipulation, surgery, or imaging of the proximal forearm.

Aged↗
PubMed1975

The influence of physical activity on ligaments and tendons.

Using either a bone-ligament-bone or a muscle-tendon-bone preparation, numerous investigators have demonstrated that the usual site of separation is in the transitional zone between the ligament (or tendon) and bone; hence, the term junction strength or load at separation is used to describe functional changes in these preparations. Junction strength is decreased with inactivity (immobilization) and increased with chronic activity (training) provided that the exercise program is of an endurance nature. Training also increases junction strength in thyroidectomized and hypophysectomized rats. Besides in junction strength, training results in heavier ligaments and higher ligament weight/length ratios. However, water content, collagen concentrations/dry weight or collagen concentration per weight/length unit are not significantly influenced by repeated bouts of exercise. Although immobilization is associated with lower elastic stiffness values (kg/mm), training appears to have little influence on this measure in normal animals. Rats and dogs with surgically repaired ligaments are weaker and the strength results are markedly lower if the leg is immobilized. Exercise training improves the repair strength of ligaments but does not result in normal values twelve weeks after the surgery. Exogenous administration of ICSH or testosterone results in higher repair strength whereas TSH, thyroxine, ACTH and growth hormone decreases this measure. It was concluded that the mechanical stress produced by chronic exercise is an important determination of the strength of repaired ligaments and of the junctions between ligaments (or tendons) and bones.

Achilles Tendon↗
PubMed1991

How to treat knee ligament injuries?

Indications for conservative treatment of knee ligament injuries can be established for all grade I or II sprains (partial tears), as well as isolated grade III sprains (complete tears) of the posterior cruciate ligament (PCL) and medial collateral ligament (MCL). These injuries should be treated with immediate mobilization. Only in isolated partial anterior cruciate ligament (ACL) tears without a positive pivot shift phenomenon is conservative treatment justified. However, many of these injuries may require operative reconstruction later. In complete ACL tears the surgical treatment consists of primary reconstruction or augmented primary repair. Today, the middle third of the patella tendon with the bone blocks is regarded as the "gold standard" for augmented repairs and late reconstructions. For the present, there is no place for synthetic prostheses in the treatment of an acute ACL rupture. Allograft replacement of the ACL must now be considered an experimental procedure. In the reconstruction of the PCL the above mentioned patella tendon graft is also preferable. Lateral collateral ligament (LCL) tears, especially if they are combined with ruptures of posterolateral ligament complex, should be repaired immediately after the injury. In these injuries late reconstructions are difficult and the results are poor. Conservative treatment of partial tears and postoperative treatment of reconstructed ligaments is twofold: on the one hand, the healing tissue should be protected and on the other hand, atrophy and wasting of uninjured tissue should be avoided. Overload and stretching of the injured ligaments should be eliminated with the aid of a suitable knee brace, but early range of motion exercises of the knee are allowed immediately.(ABSTRACT TRUNCATED AT 250 WORDS)

Humans↗
PubMed1990

[Anatomy and microstructure of the disco-malleolar ligament].

The disco-malleolar ligament was studied with the method of the anatomy and histology, and it's function was observed in the living people. It was found that the ligament takes its origin from the neck and anterior process of the malleus in middle ear and inserts into the capsule and meniscus of the temporomandibular joint. Part of the fibers was mixed with the spheno-mandibular ligament and attaches on the lingula of the mandible. The disco-malleolar ligament consists of collagenous fibers and elastic fibers. A peri-ligamentous space exists between the ligament and bone tissue. It was found the tympani membrana light cone area became smaller in opening position and larger in closing position. The existing peri-ligamentous space of the disco-malleolar ligament is a latent way between temporomandibular joint rear and tympanum.

Cephalometry↗
PubMed1990

Anatomical and radiologic studies on the lumbosacral meningo-vertebral ligaments of humans.

Among the minor soft structures of the lumbosacral spinal canal that computed tomography can visualize, the meningovertebral ligaments have been neglected. There are no specific reports on this subject, and the only knowledge we have comes from very ancient and nearly forgotten anatomical works. From our studies on cadaveric specimens, it has been confirmed that the ligaments consist segmentally of ventral and lateral fibrous bands, connecting the outer surface of the dura to the endostium of the spinal canal. The most characteristic component is the ventral one, running from the anterior wall of the dural sac to the posterior longitudinal ligament and vertebral endostium. Due to their anchoring function, the ligaments are significantly developed at the level of the dural conus (sacrodural ligaments of Trolard and Hofmann). On in vivo computed tomography studies, the ligament image appears most commonly on transverse scanograms of the lumbosacral segments as a median sagittal septum, easily identifiable when the extradural fat that it crosses is abundant. The meningovertebral ligaments may be implicated in pathological conditions of the spinal canal. They can calcify singly, though very rarely, and this process must be differentiated from degenerative marginal spurs, calcific disc herniation, circumscribed calcification of the posterior longitudinal ligament, or partial diplomyelia.

Adult↗
PubMed1990

Comparison of structure, mechanical properties, and functions of lumbar spinal ligaments.

The organization of collagen in the supraspinous, interspinous, and longitudinal ligaments, as well as the ligamenta flava, in lumbar spines from human cadavers has been investigated by polarized light microscopy, scanning electron microscopy, and x-ray diffraction. These experiments were performed on ligaments in situ, with their bony attachments undisturbed, and on excised ligaments at a range of applied strains. Results were related to the composition (investigated by standard histologic techniques) and gross structures (investigated by light microscopy) of the ligaments. More importantly, the results were related to the mechanical properties of the ligaments, which include stiffness, failure conditions, stress relaxation, and hysteresis. Where necessary, results were supplemented by or compared with those obtained from pig ligaments. Mechanical properties were related to postural changes by ligament strains induced in cadaveric specimens, using results from the literature. Thus, ligament structures could be related to their physiologic functions.

Biomechanical Phenomena↗
PubMed1990

Load tolerance, security, and failure modes of fixation devices for synthetic knee ligaments.

One weak link in synthetic ligament reconstruction of the knee is the fixation device-ligament-bone interface. In this study, a laboratory model using bovine calf bone was designed to evaluate six different fixation devices combined with either an unlooped ligament in different configurations or a looped ligament. Results are expressed in terms of maximum load to failure, elongation at the site of fixation, stiffness of fixation prior to failure, and mode of failure. When failure of the test model occurred, it was always at the ligament--fixation device interface, the fixation device--bone interface, or a combination of the two. Elongation was recorded in all modes of fixation. The most secure fixation was obtained with a cortical screw and a looped ligament, the strength and predictability being mainly dependent on bone quality. The least secure and least predictable fixation was obtained with a prototype called bucket wedge. A barbed ligament staple and an unlooped ligament also had low predictability and considerably less strength than the screw fixation but showed less sensitivity to alterations in bone quality.

Animals↗
PubMed1990

Structure-function relationship of human spinal ligaments.

A combination of light, scanning and transmission electron microscopy was used to investigate the morphology and ultrastructure of normal human spinal ligaments sampled from adult surgical specimens. The ligamenta flava consist mostly of dense elastic fibers, whereas the supraspinous and interspinous ligaments are preponderantly collagenous. In all ligaments, the collagen fascicles are characterized by a regular crimp structure. The inner collagen fibers of interspinous ligaments tend to be oriented parallel to the spinous processes while those of the peripheral layers run in postero-cranial direction. The presence of proteoglycan filaments is clearly demonstrated in all of the ligaments examined. They are mainly located at the d band of the collagen fibrils. These findings are discussed in relation to the function of the posterior ligamentous system. It is suggested that the interspinous ligaments are able to transmit tension from the thoracolumbar fascia to the spine. Finally, the spinal ligaments are thought to be involved in the control mechanism of the spine.

Adolescent↗
PubMed1988

The biological evolution of the Leeds-Keio ligament in the human knee. A histological and ultrastructural study.

The authors report their experience in the reconstruction of the anterior cruciate ligament using the Leeds-Keio ligament in 12 patients, 7 by open arthrotomy and 5 by an arthroscopic technique. The biological evolution of the new ligament was studied macroscopically and histologically in the first 6 cases treated by open arthrotomy. Arthroscopic monitoring and biopsy was carried out 4 to 10 months after operation. In 5 cases the new ligament appeared to be intact and histologically vital, with proliferation of new tissue along the new ligament. There were broken filaments of dacron hanging from the intercondylar cavity in only one case. The first macroscopic, histological and ultrastructural results show that despite a few limitations the Leeds-Keio ligament has the features required for replacement of the anterior cruciate ligament, although it will be necessary to wait 4 or 5 years before fully evaluating the durability and function of the ligament and the best operative method.

Adolescent↗
PubMed1988

Limits of movement in the human knee. Effect of sectioning the posterior cruciate ligament and posterolateral structures.

We applied specific forces and moments to the knees of fifteen whole lower limbs of cadavera and measured, with a six degrees-of-freedom electrogoniometer, the position of the tibia at which the ligaments and the geometry of the joint limited motion. The limits were determined for anterior and posterior tibial translation, internal and external rotation, and varus and valgus angulation from zero to 90 degrees of flexion. The limits were measured in the intact knee and then the changes that occurred with removal of the posterior cruciate ligament, the lateral collateral ligament, the popliteus tendon at its femoral attachment, and the arcuate complex were measured. The cutting order was varied, allowing us to determine the changes in the limits that occurred when each structure was cut alone and the amount of motion of the joint that was required for each structure to become taut and to limit additional motion when the other supporting structures had been removed. Removal of only the posterior cruciate ligament increased the limit for posterior tibial translation, with no change in the limits for tibial rotation or varus and valgus angulation. The additional posterior translation was least at full extension and increased progressively, reaching 11.4 millimeters at 90 degrees of flexion. The progressive increase in posterior translation with flexion was apparently due to slackening of the posterior portion of the capsule, as the translation nearly doubled when the posterolateral structures subsequently were removed. Removal of only the posterolateral extra-articular restraints increased the amount of external rotation and varus angulation. The average increase in external rotation depended on the angle of flexion; it was greatest at 30 degrees of flexion and decreased with additional flexion. At 90 degrees of flexion, the intact posterior cruciate ligament limited the increase in external rotation to only 5.3 degrees, less than one-half of the 13.0-degree increase that occurred at 30 degrees of flexion. Subsequent removal of the posterior cruciate ligament markedly increased external rotation at 90 degrees of flexion, resulting in a total increase of 20.9 degrees. The limit for varus angulation was normal as long as the lateral collateral ligament was intact. When the lateral collateral ligament was cut, the limit increased 4.5 degrees (approximately 4.5 millimeters of additional joint opening) when the knee was partially flexed (to 15 degrees).(ABSTRACT TRUNCATED AT 400 WORDS)

Biomechanical Phenomena↗
PubMed1988

Ipsilateral diaphyseal femur fractures and knee ligament injuries.

Three hundred and nine consecutive patients with 320 diaphyseal femur fractures were retrospectively reviewed to determine the incidence of ligament injury in the ipsilateral knee. Ligamentous injuries were diagnosed if serious (Grades II and III) instability was apparent on admission, found at surgery for femoral stabilization, or disclosed on roentgenograms during closed management. Seventeen patients with unilateral shaft fractures of the femur had ipsilateral knee ligament injuries, or 5.3%. There was no relationship between specific ligament damage and the cause of the injury or level of fracture. Twelve patients were followed for an average of 34 months. Five patients lacked full extension and ten lacked full flexion. Two of seven patients with ligament repair and three of five patients without ligament repair had at least one unstable ligament. Better range of knee motion was obtained when both the femur and ligament injuries were surgically managed, but most (seven of 12) patients were disabled.

Adult↗
PubMed1987

Classification of ligament injuries: why an anterolateral laxity or anteromedial laxity is not a diagnostic entity.

To interpret clinical laxity tests, the clinician must apply the kinematic and biomechanical concepts listed in Figure 12-13. These concepts have been briefly introduced here and are discussed in greater detail elsewhere. Figure 12-13 illustrates the importance of first selecting a laxity test to diagnose a specific ligament structure abnormality. The test selected, and the diagnostic information gained, is based on an understanding of the primary and secondary ligamentous restraints which are being tested. It is difficult to guess which ligaments are resisting specific joint displacements; therefore, biomechanical tests must first experimentally determine the restraints. Performing these tests obviates the first level of disagreement that existed when interpretations of clinical laxity tests were based only on "clinical impressions." The results of the laxity tests must be understood and communicated in terms of the six degrees-of-freedom system that determines abnormalities in motion. Resultant joint subluxations are readily understood by examining the medial and lateral tibiofemoral compartments separately. Our bumper model illustrates the different types of anterior subluxations that occur after anterior cruciate disruption. The final diagnosis of a ligament defect must be made in precise anatomic terms. In cases of partial disruption, or after healing occurs, the clinician must analyze the remaining functional capacity of the ligaments. In the future, newer diagnostic machines will provide even more detailed information enabling clinicians to determine the different types of compartmental subluxations under defined loading conditions. These machines will also provide measurements of ligament and joint stiffness. In this way, the functional deficits of the individual ligaments, and the joint as a whole, can be more readily characterized. The concepts that we have presented here can be applied qualitatively by the clinician, and in the future, they can be quantitatively applied. Our goal is to provide the basic scientific and clinical principles upon which the diagnosis and classification of ligament injuries should be based.

Humans↗