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PubMed2006

Microvascular system of anterior cruciate ligament in dogs.

This study was done to investigate the microvascular system of anterior cruciate ligament (ACL) using dogs. The objective was to study the microvascular architecture and the status of the barrier function of the capillary wall in the ACL by using microangiogram, scanning (SEM), and transmission electron microscopy (TEM). The vascular system in the ACL has been intensively studied by a number of researchers, using several microangiographic techniques in dogs, rabbits, and humans. However, most of these microangiographic studies had significant shortcomings, including the lack of three-dimensional observations and function of the blood-joint barrier in the ACL. In this study, the microstructure of the ACL was examined using microangiogram, SEM, and TEM. We investigated the vasculature of the ACL with SEM of vascular corrosion casts. In addition, we examined the status of the barrier function of the capillary wall in the ACL using the protein tracer horseradish peroxidase (HRP). Feeding vessels of the ligament were predominantly coming from the synovial-derived vessels originating from the synovium attached to the ligament near the tibial and femoral bone insertions of the ACL. The anterior cruciate ligament was surrounded by synovium, which had abundant vessels. The branches of these synovial vessels were penetrating into the ligament and making the intrinsic vascular network. It was also ascertained under SEM that the perivascular space around the intrinsic vessels were communicating through the intrinsic ligament fiber bundles and the mesh-like synovial membrane. The capillaries in the ACL were all of the continuous type under TEM. The protein tracer that was injected into the joint space passed through the synovial membrane and entered into the capillary lumen in the ACL, but the tracer that was injected intravenously did not appear in the perivascular space. The existence of a blood-ACL barrier does not necessarily imply the existence of an ACL-blood barrier. We think that the blood flow in the ACL is definitely affected by the status of joint fluid and these barriers of endothelium. The clinical relevance of the fine vascular anatomy of the ACL in trauma surgery is considered. This deserves further consideration.

Angiography↗
PubMed1996

Catabolism and loss of proteoglycans from cultures of bovine collateral ligament.

This paper investigates the kinetics and mechanism of loss of the two major proteoglycan species from cultures of bovine collateral ligament. Following incubation of ligament with [35S]sulfate after 6 days in culture, the rate of loss of the predominant proteoglycan species, decorin, from the matrix was shown to be much slower (t1/2 approximately 18 days) than that of the large chondroitin sulfate proteoglycan (t1/2 approximately 1.4 days). Analysis of 35S-labeled proteoglycans released into the medium between Days 11 and 15 of the culture period on a column of Sepharose CL-4B revealed that these macromolecules constituted mainly decorin of similar hydrodynamic size to that present in the matrix. Furthermore, analysis of core proteins using gel electrophoresis followed by fluorography or immunodetection with LF-94, an antibody directed against the amino-terminal region of decorin, indicated that the core proteins of decorin released into the medium and those remaining in the matrix of ligament cultures had a similar molecular mass (approximately 49 kDa). Analysis of both the 35S-labeled and endogenous macromolecules using 5/6/3-B-3, an antibody directed against terminal unsaturated chondroitin-6-sulfate disaccharides, revealed that three core proteins with molecular masses greater than approximately 200 kDa were present in the matrix. Four additional core proteins (range approximately 80-200 kDa) derived from the large proteoglycan were detected in the medium of ligament cultures. These findings indicate that, unlike decorin, the loss of the large chondroitin sulfate proteoglycan from the matrix of ligament cultures involved proteolytic cleavage of its core protein. No difference in the hydrodynamic size of the 35S-labeled glycosaminoglycan chains derived from either proteoglycan species remaining in the matrix or released into the medium of ligament cultures was observed.

Animals↗
PubMed1996

Identification and immunolocalization of type X collagen at the ligament-bone interface.

In some ligaments, ligamentous collagen fibrils attach to bone by first passing through non-mineralized and mineralized fibrocartilage present at the ligament-bone interface. To understand better the function of these fibrocartilages, collagens present at the femoral insertion of the bovine medial collateral ligament were isolated and characterized. Types II and IX collagens were identified in pepsin digests of the tissue in addition to type X collagen originally thought to be associated with the cartilages undergoing endochondral bone formation. Presence of type X collagen was confirmed by immunoblotting and by immunofluorescence localization using laser confocal microscopy. Type X collagen was localized predominantly in the mineralized zone of the ligament insertion. These data indicated that type X collagen may play a role in ligament attachment to bone.

Animals↗
PubMed1993

Characterization of the plasminogen activators and plasminogen activator inhibitors expressed by cells isolated from rabbit ligament and synovial tissues: evidence for unique cell populations.

Fibroblasts derived from rabbit anterior cruciate and medial collateral ligaments were found to constitutively produce and secrete a plasminogen activator (PA). The PA was identified as urokinase-like using biochemical, immunological, and molecular techniques. These fibroblasts also produced and secreted low levels of a plasminogen activator inhibitor (PAI). The inhibitor was identified as PAI-1 by biochemical and molecular techniques. The expression of both PA and PAI activity in the rabbit ligament fibroblasts increased upon addition of phorbol myristate acetate (PMA). To determine the relationship of the ligament fibroblast population to synovial fibroblasts, comparison of the biochemical characteristics of the cell types was performed. It was determined that synovial fibroblasts differed from ligament fibroblasts with respect to PA/PAI profile, type of collagen secreted, and the amount of hyaluronic acid secreted. More specifically, stimulation of synovial fibroblasts with PMA resulted in the detection of a fibrinolytic activity which was not detected in the conditioned medium from PMA-treated ligament fibroblasts. It was also shown that synovial fibroblasts secreted fourfold more hyaluronic acid than ligament fibroblasts. In addition, it was also determined that synovial fibroblasts secrete more type III collagen than do cells isolated from either the ACL or either MCL. These results support the conclusion that the cells derived from these tissues maintain distinct phenotypes in vitro.

Animals↗
PubMed1977

[Chronic fibular instability of the ankle-joint -- x-ray diagnostic and ligamentous graft (author's transl)].

It was tried to find out how many radiographs are necessary to show instabilities of the ankle-joint with ruptures of the ligamentum talofibulare anterius alone (which is the most common ligamentous lesion) and in combination with other fibular ligaments. Therefore stress views of anatomical speciems of ankle-joints with previous artifically coused lesions were done. It was found that one lateral view with the talus stressed in subluxation and one a.p. view with stressed pes equinus and supination with slight internal rotation of the foot are enough in comparison with the other side. The mostly used plastic reconstructions of old fibular ligament teares by Watson-Jones and Evans act as a tenodesis for the subtalar joint, because the natural anatomical position of the ligamentum calcaneofibulare, which should be replaced, is not respected. We looked for the best positioning of a graft as a replacement of the ligamentum calcaneofibulare by help of a string model in anatomical speciems. Only the straight graft of this ligament gives the best chance of free mobility in the subtalar joint. Other directions of this ligamentous graft lead either to a tenodesis or to an outwear of the graft without a stabilizing effect. Postoperative examinations of nine patients with ligamentous grafts stress this point.

Ankle Joint↗
PubMed1985

Clinical and radiological long-term results after primary knee ligament surgery.

A total of 77 patients were reviewed 2 to 7 years (average 40 months) after primary operative treatment of an acute knee ligament injury. Fifty percent of the injuries occurred during sports events, the other causes were traffic in 29% of cases and accidents at work, home etc. in 21% of the cases. Cross-country skiing was the cause in half of the sports accidents. There were two annual peaks in the distribution of the injuries: January-March (40% of the cases) and August-October (29%). The total number of operations increased steeply during our observation period; 57% of the operations were performed from 1980 to 1981. The most common types of injury were a combination rupture of the anterior cruciate and the medial collateral ligaments (36% of the cases) and a medial collateral ligament rupture alone (31%). According to the follow-up study, excellent or good results were obtained in 59% of the cases and fair or poor in 41%. The pathological clinical and radiological changes after knee ligament injury accumulated markedly under some specific findings. Characteristic of the patients with excellent healing results was that they were younger, received isolated ligament injury and played a great amount of sport, and of the patients with fair or poor results that they were older, received combined ligament injury, suffered quadriceps muscle atrophy and had diminished sporting activity.

Accidents↗
PubMed1996

Occipital condyle fracture and ligament injury: imaging by CT.

The true incidence of fracture of the occipital condyles is unknown. It may be associated with instability at the craniocervical joint. CT is the modality of choice for the demonstration of these fractures, but its use for imaging of the associated ligament injury has not been reported. In order to demonstrate normal anatomy, occipital condyle fracture and ligament injury, and to estimate the incidence of this lesion, 21 children and young adults with high-energy blunt craniocervical injury were examined prospectively. Thin-slice, axial, contiguous, CT was performed from the base of C2 to above the foramen magnum. Bone and soft tissue windows and coronal, sagittal, and curvilinear 2D reconstructions were performed. Five occipital condyle fractures were identified in four patients (19 %), with demonstration of alar ligament injury in two cases and local hematoma in one. In four, artifacts or rotation precluded assessment of ligaments. In all remaining cases normal bone and ligament anatomy was demonstrated. Fracture of the occipital condyles following craniocervical injury is not uncommon in children and young adults. Normal bone and ligament anatomy and pathology can be safely and clearly demonstrated in seriously injured patients and others using this CT technique. Increased awareness of this entity and a low threshold for performing CT should avoid the potentially serious consequences of a missed diagnosis.

Adolescent↗
PubMed1996

Quadriceps tendon and patellar ligament: cryosectional anatomy and structural properties in young adults.

Structural tensile properties analyses of 10-mm-wide central sections of quadriceps tendon-bone (QT-B) and bone-patellar ligament (B-PL) complexes from young male donors (mean age 24.9 years, range 19-32 years) were complemented by a cryosectional analysis: each QT-B complex was composed of the segment of the quadriceps tendon with the proximal half of the patella attached, each B-PL complex was composed of the distal half of the patella with the patellar ligament attached. A servohydraulic materials testing machine was used to assess ultimate failure load of 16 unconditioned and 16 preconditioned QT-B and B-PL complexes at an extension rate of 1 mm/s. Ligaments/tendons were preconditioned during 200 cycles from 50 to 800 N at 0.5 Hz. On cryosections the quadriceps tendons were significantly longer and thicker and exhibited a significantly larger bony attachment area than the patellar ligaments. Cross-sectional areas of 10-mm-wide, full-thickness, central parts of unconditioned quadriceps tendons were significantly greater and measured 64.6 +/- 8.4 mm2 with respect to the cross-sectional area of patellar ligaments, measuring 36.8 +/- 5.7 mm2 (P < 0.0025). Ultimate failure loads for unconditioned complexes resulted at 2173 +/- 618 N for QT-B complexes and at 1953 +/- 325 N for B-PL complexes (P = 0.43). Ultimate failure load values measured 2353 +/- 495 N for preconditioned QT-B complexes and 2376 +/- 152 N for preconditioned B-PL complexes, respectively (P = 0.77). Despite the fact that initial testing length, thickness, cross-sectional shape and area of unconditioned QT-B and B-PL complexes were significantly different, displacement at ultimate load, energy to failure and total energy were not. In terms of ultimate tensile strength, the 10-mm-wide central part of the QT-B complex compared favourably to the tensile properties of the human femur-anterior cruciate ligament-tibia complex from a comparable young age group. The evidence from anatomic, cryosectional and structural properties analyses suggests that the QT-B complex may be a valuable and versatile adjunct to the surgeon's armamentarium in reconstructive cruciate ligament surgery.

Adult↗
PubMed1999

Correlation between computed tomography and gross anatomy of the suspensory ligament of the ovary.

To assess the morphology of the suspensory ligament of the ovary on CT scan examination, an anatomic study of the suspensory ligament of the ovary was performed to demonstrate its morphology on CT and to facilitate the visualization of the ovaries. Twelve female cadavers were studied after intravascular injection of latex (venous: 2, arterial: 6, arterio-venous: 4). We first observed all the pelvises after their transection. Six dissections were then made to obtain optimal anatomic correlations on the content and relations of the infundibulo-pelvic ligament. The arterial opacifications were poor compared with to the good quality of the venous or arteriovenous opacifications. An upright correlation between CT slices and the anatomic study was made. This radio-anatomic study emphazises the importance of the veins, which really support the suspensory ligament of the ovary, as opposed to the involution of the arteries. This study points out the link between the infundibulo-pelvic ligament above and the utero-ovarian below, then with the superficial uterine vv. All these structures were well analyzed on CT and during the anatomic studies. A very well developed periovarian venous plexus which frequently concealed the ovaries was demonstrated. Some anatomic variations which were invisible on the CT scan examinations were displayed. The visualization of the suspensory ligament of the ovary should facilitate the visualization of the ovaries and could optimize the search for lymphadenopathies originating from ovarian cancers.

Aged↗
PubMed1997

Anatomic bases of the vascularized hepatic teres ligament flap.

The hepatic ligamentum teres was investigated in 30 adult specimens. The ligament represents a fibrous remnant of the umbilical v. and a small irregular lumen still exists in the ligament in adult life. The ligament is supplied by one set of independent round ligament a. and paraumbilical vv. Since the proximal segment of the ligament is easily mobilised and since the ligamentous a. originates from the right hepatic a. near the hilum, a proximal vascularized pedicle flap of the ligamentum teres has been recommended. Surgical repair of the extrahepatic bile duct using a vascularized pedicle flap of the ligamentum teres has been carried out successfully in 12 patients.

Adolescent↗
PubMed1998

The pubourethral ligaments--an anatomical and histological study in the live patient.

The aim of the study was to analyze the structure, relations and insertions of the pubourethral ligament in the living female. Thirty-five women, mean age 44 years, were studied. The intravaginal slingplasty (IVS) procedure, as performed via two paraurethral incisions, allowed immediate access to the structures in this area, the urethra, vaginal hammock, pubourethral ligaments and anterior portion of the pubococcygeus muscle. Histological biopsies were performed from the structures identified as ligaments. The pubourethral ligament descends like a fan from the lower part of the pubic bone. It consists of vaginal and urethral parts, joined together by thin fibrous threads, giving the appearance of a continuous sheet of amorphous connective tissue. Each part generally varies between 5 and 7 mm in width and 3-4 mm in thickness. The urethral part is approximately 2 cm long and inserts into the midpart of the urethra. The vaginal part is approximately 3-4 cm long. It inserts into the vaginal hammock posterolaterally, approximately 1 cm short of the bladder neck. Histologically the ligaments consist of smooth muscle, elastin, collagen, nerves and, blood vessels. The dissections confirm that the pubourethral ligaments are strong finite structures. Allowing for differences between cadavers and live patients, relationships and insertions are much as described by Robert Zacharin.

Adolescent↗
PubMed2001

Computer-assisted design of the sagittal shapes of a ligament-compatible total ankle replacement.

The poor results of total ankle replacement have been attributed to the inability of designers to restore adequately the critical mutual function of the ligaments and the articular surfaces. The purpose of this study was to design sagittal shapes of the articular surfaces for a new ankle prosthesis to be compatible with the geometry of the retained ligamentous structures. Several ligament-compatible pairs of articular surfaces were tested using a computerised version of a four-bar linkage model. The kinematics of the ankle when replaced by non-conforming two-component and by fully conforming three-component designs with either flat, concave or convex tibial surfaces were assessed by the model. A ligament-compatible convex-tibia fully-congruent three-component prosthesis showed the best features. The three-component prosthesis allows complete congruence over the entire range of flexion. A convex shape for the tibial arc was preferred because of the better degree of entrapment of the meniscal bearing. A 5 cm convex-tibia arc radius gave 2 mm entrapment together with 9.8 mm of tibial bone cut. Ligament elongation imposed by full congruence of the articular surfaces was less than 0.03% of the original length. The original patterns of joint kinematics and ligament tensioning are closely restored in the joint replaced by the proposed prosthesis.

Ankle Joint↗
PubMed1985

[Ligament replacement with polydioxanone (PDS)].

Experimentations on animals have been performed in order to verify the applicability of the slowly resorbable suturing material Polydioxanon (PDS) in the transposition of ligaments in general and the transposition of cruciate ligaments in particular. After six weeks, the absorption of a twisted cord of 2 mm diameter still has a traction tolerance of 58%. The experimentations made on rabbits and sheep suggest that PDS can be used to fasten ligament sutures and to reinforce ligament grafts. Under extremely favorable soft tissue conditions, the substance can even be used as ligament substitute. Good clinical results can be achieved in the problematic plastic surgery of the anterior cruciate ligament if the reinforcement of the autologous transplant is performed with PDS in the sense of an augmentation graft.

Animals↗
PubMed1994

[Fractures of the proximal tibia and knee ligament injuries].

The risk of secondary osteoarthritis after proximal tibial fractures is influenced by the reconstruction of both the articular surface and associated knee ligament injuries. In a follow-up of 69 operatively treated tibial head fractures 36.2% revealed ligamentous damages. At high risk were young male patients with fractures of the medial or both tibial condyles. Only 33% of the ligament damages were the cause of fracture dislocations as described by Moore. Avulsion fractures of the knee ligaments can be successfully treated on by primary fixation. For ruptures of the medial collateral ligament a functional therapy is often sufficient whereas damages of the cruciate ligaments need secondary reconstruction.

Adolescent↗
PubMed1996

[Projections and fiber characteristics of sensory afferents of the anterior cruciate ligament in an animal experiment].

The sensory innervation of the rabbit anterior cruciate ligament was studied by retrograde tracing technique using wheat-germ-agglutinin-horseradish-peroxidase (WGA-HRP) and Fast Blue as neuronal tracers. Injection of the tracer into the ligament was followed by histo- and immunohistochemical investigation of labelled nerve cell bodies located in the dorsal root ganglia. In 4 animals we injected the tracer into the joint cavity to label general joint afferents. The segmental distribution of retrogradely labelled neurons following injection into the anterior cruciate ligament (L6, L7, S1) is significantly different from the distribution pattern after injection into the knee joint (L4-S2). Retrogradely labelled nerve cells innervating the anterior cruciate ligament were further investigated using immunohistochemical and morphometric analysis. The sensory innervation of the anterior cruciate ligament is therefore comprised of at least 2 different qualities of sensory afferent nerves: 1. Small neurones immunoreactive to the inflammatory peptide substance P most likely transmitting nociceptive information centrally (44%). 2. Large, presumably fast conducting A-fibre-afferents characterized by neurofilament proteins transmitting proprioceptive information from corpuscular mechanoreceptors (43%). The results of this study put further weight to the importance of the sensory role of the anterior cruciate ligament using neuroanatomical and immunohistochemical techniques.

Afferent Pathways↗
PubMed1997

Intraligamentous nerves as a potential source of pain after sacrospinous ligament fixation of the vaginal apex.

The aim of the study was to investigate the histology of the sacrospinous ligament to determine whether nerve fibers exist within the substance of the sacropinous ligament itself. Six sacrospinous ligaments were removed from 4 fixed female cadavers. Representative segments were taken from the lateral (ischial), middle and medial (sacral) portions of these specimens, sectioned by microtome, mounted, and stained with hematoxylin and eosin dyes. The fixed and stained sections were then examined using light microscopy. Nerve tissue was found to be concentrated in the medial portions of the sacrospinous ligaments, but nerves were found in all segments of the ligament. It was concluded that, nervous tissue is present and widely distributed within the body of the sacrospinous ligament. A wide variety of sizes and thicknesses are also demonstrated, suggesting a variety of functions, including possible pain reception. This fact should be taken into consideration when planning operative procedures for pelvic prolapse.

Cadaver↗
PubMed1993

Bone-like nodules formed in vitro by rat periodontal ligament cells.

The periodontal ligament has been shown to possess the ability to regenerate both new cementum and alveolar bone as well as a self-regenerative capacity; however, the source of cementoblasts and osteoblasts is not still clear. We investigated the development of bone-like tissue in vitro by periodontal ligament cells, in order to determine whether the periodontal ligament contains osteoprogenitor cells. Periodontal ligament cells were obtained from periodontal ligament tissue attached to the maxillary incisors of 6-week-old WKA rats by means of the explant technique. Cells at passage #3 were cultured for long term in alpha-minimum essential medium containing 10% fetal bovine serum, antibiotics, and 50 micrograms/ml ascorbic acid, and were then examined using phase-contrast microscopy, histochemistry, transmission electron microscopy, X-ray microanalysis, and electron diffraction. Nodules were formed in the cultures, and when 10 mM Na-beta-glycerophosphate was added, these nodules became mineralized. The mineralized nodules were identified as bone-like elements in view of the presence of osteoblast-like and osteocyte-like cells, collagenous matrix, a mineral composed of hydroxyapatite, and intense alkaline phosphatase activity. The results show that the periodontal ligament contains osteoprogenitor cells, which differentiate into osteoblasts and produce bone-like tissue.

Animals↗
PubMed2003

Determination of the mechanical properties of the periodontal ligament in a uniaxial tensional experiment.

BACKGROUND: The periodontal ligament is a soft connective tissue which joins the tooth root to the alveolus and thus provides for anchorage of the tooth in the alveolar bone. Due to its composition of elastic and viscous components, this tissue displays viscoelastic material properties. In a previous study [4], in vitro experiments revealed typical viscoelastic material properties of the periodontal ligament in samples from pig mandibles. These properties included force relaxation, hysteresis, and dependence on loading history. MATERIAL AND METHODS: Based on those experiments, a dependence of tooth displacement on loading velocity was registered in the present study and the stress-strain behavior of the periodontal ligament was examined until the tissue ruptured. For this purpose, segments of the periodontal ligament taken from anterior teeth from the pig mandible were tested in a purpose-developed clamping fixture in a uniaxial tensional experiment. RESULT: It was found that the initial phase of the stress-strain curve in particular was dependent on loading velocity and that the shape of the hysteresis curve was subject to a variation in loading velocity. The stress-strain behavior of the periodontal ligament was characterized, divided into several phases, and the elastic modulus of the initial and the linear phase of the curve was determined at different loading velocities. CONCLUSION: Knowledge of the material properties of the periodontal ligament is fundamental to an understanding of orthodontic tooth movement and thus to selection of an optimal force system for orthodontic treatment.

Animals↗