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PubMedDate not supplied

The effect of posterior cruciate ligament injury and reconstruction on meniscal strain.

BACKGROUND: The relationship between posterior cruciate ligament insufficiency and meniscal injury is unclear. HYPOTHESIS: Posterior cruciate ligament insufficiency results in increased medial and lateral meniscal strain. STUDY DESIGN: Descriptive anatomic study. METHODS: Eight cadaveric specimens were evaluated with a 6-axis load cell and differential variable reluctance transducer strain gauges placed in both menisci. Data were recorded in the posterior cruciate ligament-intact state after posterior cruciate ligament transection and after posterior cruciate ligament reconstruction. RESULTS: The effect of posterior cruciate ligament state on meniscal strain was more pronounced at higher flexion angles. At 60 degrees and 90 degrees of flexion, there was a significant effect of posterior cruciate ligament sectioning and reconstruction on meniscal strain (P < .026). Average meniscal strain for both medial and lateral menisci increased between the intact and the posterior cruciate ligament-cut states. Posterior cruciate ligament reconstruction decreased strain values to that of the intact knee. CONCLUSIONS: Meniscal strain increases with complete posterior cruciate ligament injury and is returned to posterior cruciate ligament-intact levels after posterior cruciate ligament reconstruction. CLINICAL RELEVANCE: Posterior cruciate ligament reconstruction may play an important role in reducing meniscal strain and subsequent degeneration within the posterior cruciate ligament-injured knee.

Biomechanical Phenomena↗
PubMedDate not supplied

Increased tibial translation after partial sectioning of the anterior cruciate ligament. The posterolateral bundle.

We measured changes in anterior translation of the tibia with sequential sectioning of the bundles of the anterior cruciate ligament and correlated these changes with the clinical examination. Six fresh cadaveric lower extremities were examined by three experienced knee surgeons in a masked fashion with the anterior cruciate ligament intact and after sectioning of the posterolateral bundle, the posterolateral bundle and 50% of the anteromedial bundle, and the entire ligament. Lachman, anterior drawer, and lateral pivot shift tests were performed. Both KT-1000 arthrometer testing (30 pounds) and biplanar radiography demonstrated progressive increases in anterior translation with incremental sectioning of the anterior cruciate ligament. However, significant (P < 0.05) increases in translation were found only after sectioning both the posterolateral bundle and half of the anteromedial bundle and after complete sectioning of the anterior cruciate ligament. The examiners were accurate in their interpretation of the status of the anterior cruciate ligament in 89% of the intact specimens and 80% of completely sectioned ligaments. Only 11% of the examinations correctly diagnosed the anterior cruciate ligament as partially cut when the posterolateral bundle was sectioned. A soft end point to the Lachman examination was noted only after cutting at least 75% of the ligament, but was not always present. Clinical evaluation is accurate in defining intact and completely sectioned anterior cruciate ligaments. However, it is unable to differentiate a sectioned posterolateral bundle from an intact anterior cruciate ligament, or a 75% sectioned ligament from a completely sectioned ligament. The clinical diagnosis of a partial tear of the anterior cruciate ligament is more likely to represent a complete or "functionally complete" tear.

Aged↗
PubMedDate not supplied

Posterior cruciate ligament insufficiency. A review of the literature.

A review of the English language literature establishes athletic mishaps as a major cause of posterior cruciate ligament injury. However, diversity of opinion exists regarding the functional significance of the lesion, its occurrence as an isolated entity, and the roles of conservative and surgical management. The posterior cruciate ligament is a composite structure, consisting of a superficial tibiofemoral and meniscofemoral portion and a deep tibiofemoral portion. The structure is intra-articular but extrasynovial, coursing from its attachment to the lateral surface of the medial femoral condyle posteriorly and inferiorly to its distal attachment into the posterior rim of the tibia, blending with the capsule and periosteum. Mechanical studies have demonstrated that abnormal posterior tibial displacement can occur only with posterior cruciate ligament laxity. The most prevalent mechanism resulting in injury to the posterior cruciate results from a blow on the anterior aspect of the flexed knee. However, both hyperflexion and hyperextension as well as deceleration and rotation have been described. Posterior cruciate ligament insufficiency may result from an avulsion fracture involving the ligament-bone insertion of the ligament, usually from the posterior aspect of the proximal tibia. Also, disruption may occur as an intersubstance tear of the ligament, either as an isolated phenomenon or in combination with multiple ligamentous injuries. The importance of distinguishing between combined injuries associated with significant collateral and/or anterior cruciate ligament injuries from the 'isolated' type lies in the fact that the prognosis for the 'isolated' injuries is much better. Careful clinical evaluation of the knee with an acute posterior cruciate ligament injury will reveal subtle, but definite, findings peculiar to the lesion. These include the posterior sag sign, the posterior drawer sign, reverse pivot shift, Godfrey's test, and the presence of varus or valgus instability with the joint in full extension. In patients with chronic posterior cruciate ligament laxity, the presenting symptom is often that of patellar pain. It is generally agreed that avulsion fractures involving the ligament-bone insertion of the posterior cruciate ligament should be treated by open reduction and internal fixation. Surgical treatment of this lesion will result in excellent functional recovery. A variety of procedures have been reported for the management of acute disruption of the posterior cruciate ligament.(ABSTRACT TRUNCATED AT 400 WORDS)

Acute Disease↗
PubMed1993

Dorsal carpal ligaments of the wrist: normal appearance on multiplanar reconstructions of three-dimensional Fourier transform MR imaging.

OBJECTIVE: Three-dimensional Fourier transform MR imaging techniques can produce much thinner contiguous slices than are obtainable with standard two-dimensional Fourier transform MR imaging techniques. The improved spatial resolution and capabilities for interactive multiplanar displays allow improved visualization of small, complex anatomic structures such as the carpal ligaments. The purposes of this study were twofold: (1) to determine if the dorsal carpal ligaments can be visualized consistently with three-dimensional Fourier transform MR imaging techniques with multiplanar reconstructions and (2) to evaluate the size, shape, orientation, and right-to-left symmetry of the dorsal carpal ligaments in both wrists of 25 asymptomatic volunteers as a basis for future comparison when patients with suspected ligament injuries are seen. SUBJECTS AND METHODS: Both wrists of 25 asymptomatic volunteers were imaged with a three-dimensional Fourier transform MR imaging technique with commercially available equipment. A three-dimensional graphic workstation was used to reconstruct oblique two-dimensional images in the long axes of the radiotriquetral and dorsal intercarpal ligaments in all 50 wrists. The size, shape, orientation, and right-to-left symmetry were determined by the author using the reconstructed two-dimensional images. RESULTS: The radiotriquetral ligament and dorsal intercarpal ligament were visualized in all 50 wrists. The radiotriquetral ligament consisted of a single band arising from the distal radius (next to Lister's tubercle) in 84% and had dual origins from the styloid process of the radius and Lister's tubercle in 16%. The dorsal intercarpal ligament consisted of a single broad band in 14% of wrists, was a branched structure with separate triquetroscaphoid and triquetrotrapezial fascicles in 44%, had completely separate triquetroscaphoid and triquetrotrapezial fascicles in 38%, and had a triquetrotrapezial fascicle larger than the triquetroscaphoid fascicle in 4%. The dorsal intercarpal ligamentous anatomy was symmetric in 16 of 25 volunteers. CONCLUSION: The major dorsal carpal ligaments can be visualized consistently when using three-dimensional Fourier transform MR imaging techniques and multiplanar reconstructions. The dorsal carpal ligaments are usually symmetric in size and morphology; therefore, MR images of the contralateral wrist may be used for comparison with MR images of a patient's injured wrist. The size and shape of the dorsal carpal ligaments are described for comparison with findings in patients who have suspected ligamentous injuries.

Adolescent↗
PubMed1994

MR diagnosis of complete tears of the anterior cruciate ligament of the knee: importance of anterior subluxation of the tibia.

OBJECTIVE: The primary role of the anterior cruciate ligament is to resist anterior subluxation of the tibia. When the ligament is torn, the tibia is free to sublux anteriorly when the leg is pulled forward. In addition to visualizing the anterior cruciate ligament directly, MR imaging can show joint alignment. The purpose of this study was to test the efficacy of MR images of anterior subluxation of the tibia for diagnosing complete tears of the anterior cruciate ligament. MATERIALS AND METHODS: We evaluated the records of 120 consecutive patients who underwent MR imaging of the knee and subsequently had arthroscopy. Arthroscopy showed a complete tear of the anterior cruciate ligament in 21 patients, a partial tear in eight patients, and an intact anterior cruciate ligament in 91 patients. Two radiologists together reviewed the MR images, and interpretation of anterior cruciate ligament integrity was reached by consensus. The anterior cruciate ligament was categorized as intact, completely torn, or partially torn on the basis of conventional MR imaging criteria. The degree of anterior subluxation of the tibia was measured on a separate occasion in random order by a radiologist who used a sagittal section through the middle of the lateral femoral condyle. On the selected image, two vertical lines parallel to the left and right margins of the image frame were drawn tangent to the posterior cortical margins of the lateral femoral and tibial condyles. Anterior subluxation of the tibia was determined by the distance in millimeters between these two lines and measured with calipers by using the 5-cm scale on the images. Measurements were considered reliable only to one half of the smallest increment of this scale (i.e., 5 mm). Accordingly, tibial subluxation (x) was measured in 5-mm increments, with x < or = 0 mm designated grade 0, 0 mm < x < or = 5 mm designated grade 1, 5 mm < x < or = 10 mm designated grade 2, and so forth. RESULTS: Conventional MR imaging criteria had 90% sensitivity and 94% specificity for diagnosing complete tears of the anterior cruciate ligament. According to the receiver-operating-characteristic (ROC) curve, anterior subluxation of the tibia greater than 5 mm (grade 2 or greater) was considered to be the optimal threshold (sensitivity, 86%; specificity, 99%) for diagnosing complete tears of the anterior cruciate ligament. Notably, none of the six false-positive diagnoses of complete tears by conventional criteria (three partial tears and three intact ligaments at arthroscopy) were misdiagnosed when tibial subluxation was used as the diagnostic criterion. Subluxation greater than 5 mm can be falsely negative with chronic tears of the anterior cruciate ligament (n = 2) or when a displaced bucket-handle tear of the lateral meniscus blocks anterior subluxation of the tibia (n = 1). CONCLUSION: An anterior tibial subluxation greater than 5 mm (grade 2 or greater) is a simple objective measurement that serves as a helpful adjunctive sign in the diagnosis of complete tears of the anterior cruciate ligament. This sign also offers improved discrimination of complete from partial tears of the anterior cruciate ligament.

Adult↗
PubMed2004

Anterior cruciate ligament ganglia and mucoid degeneration: coexistence and clinical correlation.

OBJECTIVE: The purpose of our study was to describe the MR appearance and coexistence of anterior cruciate ligament ganglia with mucoid degeneration and to address the clinical significance of these entities. MATERIALS AND METHODS: A database search of 4221 knee MRI examinations over 2 years revealed 90 examinations with reported anterior cruciate ligament ganglion or mucoid degeneration. Imaging criteria for ligament ganglion included fluid signal in the ligament disproportionate to joint fluid showing mass effect on intact ligament bundles. The size, location, complexity, and degree of lobulation of ganglia were recorded. Criteria for mucoid degeneration included ligament bundles poorly seen on T1-weighted and proton density-weighted images but with both bundles seen as intact on T2-weighted images. Intraosseous cysts at the ligament attachments and presence of joint effusion were noted. Clinical assessment of ligament instability was recorded when available. RESULTS: Of 74 examinations that met imaging criteria, 56 (76%) had discrete intraligamentous ganglia, 18 (24%) had mucoid degeneration, and 26 (35%) had features of both. Ganglia were located in the proximal ligament in 16 examinations (22%) and the distal ligament in 10 (14%) and involved the entire ligament in 30 (40%). Ganglia ranged in maximum diameter from 20 to 73 mm (mean, 31 mm). Complexity of ganglia was mild (41%), moderate (39.2%), or marked (19.8%). Intraosseous cysts were noted proximally in 48 examinations (65%) and distally in 20 (27%). Of 52 patients with accessible records, 48 had no clinical evidence of instability. Twelve patients who underwent arthroscopy had an intact anterior cruciate ligament at that time. CONCLUSION: Anterior cruciate ligament ganglia and mucoid degeneration commonly coexist on MRI and are typically not associated with ligament instability.

Adult↗
PubMed2002

Benign anatomical mistakes: right and left coronary ligaments.

Peritoneal attachments of the liver to the diaphragm include the falciform ligament, the left triangular ligament, and the coronary ligament with the right triangular ligament. It is often surgically convenient when the gastroesophageal junction is explored to refer to a "right" and a "left" coronary ligament, but this is anatomically unjustified. To reassess the issue there are no "right" and "left" coronary ligaments; there are only the left triangular ligament and the complex of coronary and right triangular ligament. The latter is the lateral unification of the layers of the coronary ligament. The liver is posteriorly connected to the diaphragm, and therefore the coronary ligament has superior and inferior layers rather than anterior and posterior layers. Embryologically these ligaments reflect the remnants of the developmental pathways of the liver in the septum transversum, and in the mature organism they are peritoneal connections. Besides the liver is suspended in the bare area mostly by fibrous attachments and by the hepatic veins. Consequently the term "ligament" for these structures has to be revised. Therefore we suggest the terms "left triangular peritoneal attachment" of the liver and "coronary peritoneal attachment" instead of "left triangular ligament" and "coronary ligament."

Digestive System Surgical Procedures↗
PubMed2002

[Influence of the height of the joint space on the three-dimensional kinetics of total knee prostheses and behavior of the lateral ligaments: an in vitro study].

PURPOSE OF THE STUDY: The level of the joint space can be modified after implantation of a total knee prosthesis. Likewise, ligament balance is a cardinal point of the surgical technique. The purpose of this in vitro work was to study the influence of the position of the distal tibiofemoral joint space after implantation of a total knee prosthesis on the three-dimensional kinetics of the knee joint and on the behavior of the lateral ligaments. MATERIAL AND METHOD: Total knee arthroplasty (TKA) with a posterior stabilized prosthesis was performed on seven fresh-frozen cadaver specimens. A specially-designed experimental device was used to achieve continuous knee motion simulating hip flexion from a vertical position. The Vicon optoelectronic system was used to record the femorotibial and femoropatellar kinematics in three dimensions. Two electronic goniometers were positioned on the insertions of the lateral ligaments to measure ligament displacements during knee movements. Five configurations were recorded on each knee: healthy knee, same knee after TKA, and 2-mm and 4-mm upward displacement of the prosthetic distal tibiofemoral joint space. Ligament balance at extension was preserved in all configurations. The kinematic curves obtained were compared with the coefficient of multiple correlation. RESULTS: Changing the position of the joint space had a significant effect on the kinematics of the patella (rotation and abduction-rotation) but did not have a significant effect on the femorotibial kinematics. Variations in the length of the lateral ligaments were of small amplitude. Lowering the joint space led to laxity at flexion. Raising the joint space tightened the ligaments at flexion. DISCUSSION: These results confirm our clinical impression when the level of the distal femur cut is set to achieve tension on the ligaments at knee extension. If the joint space is lowered, i.e. with a more sparing distal femur cut, the prosthesis takes up less space during flexion, leading to laxity at flexion. If the joint space is raised, i.e. with an excessive distal femur cut, the prosthesis takes up more space during flexion, tightening the lateral ligaments. CONCLUSION: The position of the joint space must be rigorously reproduced during TKA not only to maintain correct femorotibial kinematics, but most importantly to preserve patellar kinematics and proper behavior of the lateral ligaments. Ideally, the height of the joint space should be restored first, followed by control of the ligament balance. An over- or undercut of the femur can lead to defective femoropatellar kinematics and ligament tension at flexion despite good ligament balance at extension. In addition, ligament balance should not be achieved by displacing the tibial cut or by modifying the thickness of the tibial component, which would have an effect not only at extension but also at flexion.

Anthropometry↗
PubMed1991

The effects of in situ freezing on the anterior cruciate ligament. An experimental study in goats.

We developed an in situ freeze-thaw model designed to simulate an ideally placed and oriented autogenous graft of the anterior cruciate ligament. In this model, the anterior cruciate ligament was exposed, and the femoral insertion, tibial insertion, and body of the anterior cruciate ligament were frozen in situ with specially designed freezing probes. Freeze-thaw cycles were repeated five times. We used the technique in thirty-three mature goats to study the biological and biomechanical outcomes of the devitalized and devascularized anterior cruciate ligament at zero, six, and twenty-six weeks after treatment. Thus, the collagen fibers of the simulated autogenous graft remain in normal anatomical position and the simulated graft is fixed under physiological tension. At twenty-six weeks, no statistically significant differences were noted between treated and contralateral control (untreated) ligaments relative to anterior-posterior translation, maximum force to rupture, stiffness in the linear region of the force-length curve, modulus of elasticity in the linear region, strain to maximum stress, or maximum stress. The only statistically significant difference was an increase in cross-sectional area of the ligament. This increase was 22 and 42 per cent greater than that in the control ligaments at six weeks and six months. At six months, the ligaments in the control group had an average mid-cross-sectional area of 17.7 +/- 1.2 square millimeters and the ligaments in the experimental group, 25.2 +/- 3.1 square millimeters. Changes in the size and density of the collagen fibrils also were demonstrated at six months. These observations are in sharp contrast to our previous studies of replacement of the anterior cruciate ligament, in which an allograft of the ligament or an allograft supplemented with a 3M ligament augmentation device (LAD; 3M, St. Paul, Minnesota) was used. In those studies, an average reduction in maximum strength of 75 per cent for the allografts and 50 per cent for the allografts that had a ligament-augmentation device was found at one year. We concluded that devitalized, devascularized anterior cruciate ligaments do not lose strength if the anatomical position and the orientation of the collagen fibers are not altered.

Animals↗
PubMed1991

Healing of the transected anterior cruciate ligament in the rabbit.

Healing of the anterior cruciate ligament was studied in 170 male rabbits. One group included immature animals that had open epiphyses, and a second group consisted of only mature animals. In one knee of each animal, the anterior cruciate ligament was transected either completely or partially, and in the contralateral knee a sham operation was carried out. Mechanical testing and histological studies of the ligaments were done immediately postoperatively and at two weeks, six weeks, three months, and one year. As we expected, there was no regeneration after complete transection of the anterior cruciate ligament, and all of the animals in which this procedure was done had severe osteoarthrosis of the joint at three months. Postoperatively, the partially sectioned ligaments exhibited one-third of the strength of the ligaments on the side on which the sham operation had been done in the immature animals and one-fourth of the strength of the ligaments on the side on which the sham operation had been done in the mature animals. Subsequently, there was secondary complete rupture of 20 per cent of the partially sectioned ligaments. The remaining 80 per cent of the partially sectioned ligaments were clearly weaker two weeks after the operation than immediately postoperatively, but this was also true on the side on which the sham operation had been done. At six weeks, the initial postoperative strength of the partially sectioned ligaments had been regained. At one year, the ligaments of the immature animals were two-thirds as strong as those on the contralateral side, and those of the mature animals were three-fourths as strong as those on the contralateral side. The ligaments were markedly elongated, especially in the mature animals. At three months, stiffness of the ligaments returned to normal. Histologically, the defect was filled with tissue that was still somewhat different from normal ligamentous tissue.

Aging↗
PubMed1983

The biological reaction of the tissues to carbon fibre ligament prosthesis in sheep-knees.

The biological reaction of the tissues to carbon fibre ligament prosthesis was examined in sheep knees. Connective tissue and bone grew into the alloplastic ligament at the insertion points in cancellous bone. There was tissue ingrowth around the carbon fibres intra- and extra-articularly. The bony ingrowth into the ligament increases with time and there was no resorption present. The carbon fibre ligament should not be used as an internal splint in the fresh ligamentous repairs. The easiest method of ligament replacement in a chronically unstable knee is the application of alloplastic ligament material. Therefore the search for a good substitute has never been given up. Carbon fibres are found to be a very good scaffolding and a permanent prosthesis for ligament replacement [1, 2, 6, 8]. The biocompatibility of carbon fibres in animals has been proved [4, 6, 7]. The mechanical properties, tensile strength and flexibility, make the fibres suitable for use as ligament substitutes. The braiding of carbon fibre bundles has improved its biomechanical properties [3]. In this study the biological reaction of sheep-knees to carbon implants is investigated: 1. Does connective tissue grow into the ligament prosthesis under physiological conditions? 2. Is there tissue growth around the carbon ligaments intraarticularly? 3. Is a C-ligament useful as an internal splint in fresh ligamentous repairs? 4. What is the fate of the bone-ligament interface in long term use?

Animals↗
PubMed1999

Characterization of chemotactic migration and growth kinetics of canine knee ligament fibroblasts.

Migration and proliferation of ligament fibroblasts are essential for the healing of ligament injuries. This study was designed to evaluate the migration of intraarticular (anterior and posterior cruciate) and extraarticular (medial and lateral collateral) ligament fibroblasts in response to cytokines and to determine the effect of cell passage on cell proliferation. Recombinant human platelet-derived growth factor, hepatocyte growth factor/scatter factor, and bone morphogenic protein-2 stimulated the migration of all ligament cells in a dose-dependent manner, with optimal migration at 10 ng/ml. Recombinant human epithelial growth factor preferentially stimulated the migration of intraarticular ligament fibroblasts, whereas recombinant human interleukin-1 was more effective with extraarticular ligament fibroblasts. Recombinant human insulin-like growth factor-1, insulin-like growth factor-2, transforming growth factor-beta, and fibroblast growth factor had no significant effect on the migration of ligament-derived fibroblasts. These data suggest that specific cytokines stimulate the migration of knee ligament fibroblasts and provide a rationale for possible therapeutic approaches to optimize ligament healing. Fibroblasts derived from the anterior cruciate ligament have been shown to proliferate at a slower rate than those derived from the medial collateral ligament. We have extended these observations and have demonstrated that fibroblasts from both the posterior and anterior cruciate ligaments proliferate at a slower rate than lateral and medial collateral ligament-derived fibroblasts. The differences between the growth rates of intraarticular and extraarticular fibroblasts become insignificant with serial passaging of the cells.

Animals↗
PubMedDate not supplied

[ligament kinematics of the ankle joint. An experimental study].

In an experimental study using osteo-ligamentous preparations of ankle joints we studied the ligamentous kinematics of isolated ligament fibers of different lateral and medial ankle ligaments. Results demonstrate a different kinematic pattern of the ligaments depending on the joint position. The anterior fibula-talar ligament shows an anisometric characteristic of different fibers and demonstrates a maximal ligament strain of the most anterior fiber in maximal plantarflexion; fibers located more dorsally have their maximal strain in plantarflexion of less degrees. In contrast to that the fibula-calcaneus ligament demonstrates a more isometric characteristic. At the medial side the different parts of the deltoid ligament also demonstrate a different kinematic characteristic. In contrast to the pars tibio-calcanearis which has a more isometric ligament kinematic of isolated fibers, ligament fibers of the pars tibiotalaris posterior demonstrate an anisometric ligament kinematic. For clinical aspects an anatomically correct reconstruction of ruptured ligaments and fractures as well as an anatomic reconstruction in chronic unstable ankle joints is recommended.

Ankle Joint↗
PubMed2003

Magnetic resonance imaging of the cervical ligaments in the absence of trauma.

STUDY DESIGN: Prospective study of cervical spine magnetic resonance imaging. OBJECTIVES: To determine the frequency of nonvisualization of the cervical spinal ligaments in patients who have not suffered acute spinal trauma. SUMMARY OF BACKGROUND DATA: The cervical ligaments appear on magnetic resonance studies as a thin hypointense line, the "black stripe." Discontinuity of this "black stripe" is considered a reliable sign of ligament rupture following acute spinal trauma. METHODS: Twenty patients (13 female and 7 male, mean age 45.5 years, range 28-58 years) undergoing magnetic resonance imaging for cervical degenerative disc disease were examined using sagittal T1- and T2-weighted fast spin echo sequences. The status of the anterior longitudinal ligaments and posterior longitudinal ligaments was assessed on T1-weighted images from C2 to T1 (total of 120 levels), the ligamentum flavum from C1 to T1 (140 levels), and the apical ligament on both T1 and T2 weighted images (20 levels). The presence and sites of degenerative change were also noted. RESULTS: On the T1-weighted images, only 74-79% of anterior longitudinal ligaments, 36-74% of posterior longitudinal ligaments, 63-65% of ligamentum flavums, and 35-60% of apical ligaments were visualized. On T2-weighted images, all the apical ligaments were seen. An association was identified between nonvisualization of the anterior longitudinal ligaments on T1 and the presence of anterior osteophytes. CONCLUSION: Discontinuity of the "black stripe" on a T1-weighted sequence cannot be used as a reliable isolated sign of ligament rupture in the setting of acute spinal trauma, because the spinal ligaments are commonly not visualized.

Adult↗
PubMed2000

Geometric and mechanical properties of human cervical spine ligaments.

This study characterized the geometry and mechanical properties of the cervical ligaments from C2-T1 levels. The lengths and cross-sectional areas of the anterior longitudinal ligament, posterior longitudinal ligament, joint capsules, ligamentum flavum, and interspinous ligament were determined from eight human cadavers using cryomicrotomy images. The geometry was defined based on spinal anatomy and its potential use in complex mathematical models. The biomechanical force-deflection, stiffness, energy, stress, and strain data were obtained from 25 cadavers using in situ axial tensile tests. Data were grouped into middle (C2-C5) and lower (C5-T1) cervical levels. Both the geometric length and area of cross section, and the biomechanical properties including the stiffness, stress, strain, energy, and Young's modulus, were presented for each of the five ligaments. In both groups, joint capsules and ligamentum flavum exhibited the highest cross-sectional area (p < 0.005), while the longitudinal ligaments had the highest length measurements. Although not reaching statistical significance, for all ligaments, cross-sectional areas were higher in the C5-T1 than in the C2-C5 group; and lengths were higher in the C2-C5 than in the C5-T1 group with the exception of the flavum (Table 1 in the main text). Force-deflection characteristics (plots) are provided for all ligaments in both groups. Failure strains were higher for the ligaments of the posterior (interspinous ligament, joint capsules, and ligamentum flavum) than the anterior complex (anterior and posterior longitudinal ligaments) in both groups. In contrast, the failure stress and Young's modulus were higher for the anterior and posterior longitudinal ligaments compared to the ligaments of the posterior complex in the two groups. However, similar tendencies in the structural responses (stiffness, energy) were not found in both groups. Researchers attempting to incorporate these data into stress-analysis models can choose the specific parameter(s) based on the complexity of the model used to study the biomechanical behavior of the human cervical spine.

Analysis of Variance↗
PubMedDate not supplied

Collateral ligaments of the ankle: high-resolution MR imaging with a local gradient coil and anatomic correlation in cadavers.

Findings at high-resolution magnetic resonance (MR) imaging of the lateral and medial collateral ligaments of the ankle were compared with findings in anatomic sections from cadavers. MR imaging of six cadaveric feet was performed with a newly developed local gradient coil and axial and coronal T1-weighted spin-echo sequences. Axial imaging provided optimum views of the anterior and posterior talofibular ligaments, the deep layers of the medial collateral ligament, and the tibionavicular ligament. Coronal imaging allowed complete visualization of the calcaneofibular, posterior talofibular, tibiocalcaneal, and posterior tibiotalar ligaments. In both imaging planes, differentiation of the deep and superficial layers of the medial collateral ligament was possible. Differentiation between the syndesmotic complex and the lateral collateral ligament was accomplished easily; in particular, differentiation of the posterior tibiofibular ligament from the posterior talofibular ligament was not difficult because of the differing insertions of these ligaments. The inhomogeneous appearance of the medial collateral ligament and the posterior talofibular ligament on MR images correlated with areas of fatty tissue on corresponding microscopic sections. High-resolution MR imaging with a newly developed local gradient coil allows excellent visualization of the lateral and medial collateral ligaments of the ankle.

Adipose Tissue↗
PubMedDate not supplied

Partial tears of the anterior cruciate ligament. Are they clinically detectable?

Eight cadaveric lower extremities were examined by three experienced knee surgeons in blinded fashion. The knees were examined with intact anterior cruciate ligaments, sectioned anteromedial bundles, and completely sectioned anterior cruciate ligaments to evaluate detectable laxity changes. Lachman, anterior drawer, lateral pivot shift, and KT-1000 arthrometer testing were performed. Optimized biplanar radiography using a defined spatial coordinate reference system was performed with a 30-pound anterior force at 30 degrees of flexion to confirm clinical findings. Physical examination and arthrometer testing detected no difference between intact and partially sectioned anterior cruciate ligaments; these ligaments were significantly different than completely sectioned ligaments, with the Lachman test being the most sensitive. Despite consistent clinical detection of complete sectioning of the anterior cruciate ligament by both physical examination and arthrometer testing, neither method proved accurate in the diagnosis of isolated tears of the anteromedial bundle, but both did show that partially sectioned anterior cruciate ligament closely resembled intact ligament and differed significantly from completely sectioned ligament, as confirmed by radiologic data. Clinically diagnosed "partial tear" is likely to be complete rupture of the anterior cruciate ligament. Historically, clinically diagnosed partial tears of the anterior cruciate ligament have tended to "progress" to symptomatic instability. Our data imply these patients may have had functionally incompetent ligaments from time of injury and, in fact, were demonstrating the expected natural history of an anterior cruciate ligament-deficient knee.

Anterior Cruciate Ligament↗
PubMed1993

Direct in vitro measurement of forces in the cruciate ligaments. Part II: The effect of section of the posterolateral structures.

Specially designed load-transducers were applied to eight fresh-frozen cadaveric knee specimens in order to measure resultant forces in both cruciate ligaments as the knees were subjected to straight varus-valgus bending moment and to tibial torque (with and without a superimposed posterior tibial force). The forces in the ligaments and tibial rotation were recorded at seven angles of flexion of the knee, between 0 and 90 degrees, before and after section of the posterolateral structures. Ligamentous section increased angulation of the tibia when varus moment was applied to the knee; the large increases in lateral opening of the knee joint were accompanied by increases in the force in the anterior cruciate ligament at all angles of flexion and increases in the force in the posterior cruciate ligament between 45 and 90 degrees of flexion. When valgus moment was applied, there were no significant changes in valgus angulation or the resultant force in either cruciate ligament after ligamentous section. Ligamentous section increased rotation of the tibia when external torque was applied to the knee. The increased external rotation was accompanied by decreases in the force in the anterior cruciate ligament between 0 and 20 degrees of flexion of the knee and increases in the force in the posterior cruciate ligament between 45 and 90 degrees of flexion. In the studies involving applied internal tibial torque, after ligamentous section, rotation of the tibia increased slightly between 60 and 90 degrees of flexion. The force in the anterior cruciate ligament increased between 0 and 20 degrees of flexion, while the force in the posterior cruciate ligament was unaffected.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗