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At least 757 records · Page 42Linked to original sources
PubMed2001

Mechanical behavior of the Lisfranc and dorsal cuneometatarsal ligaments: in vitro biomechanical study.

OBJECTIVES: To define the anatomy and mechanical properties of two ligaments stabilizing the medial tarsometatarsal joints: the Lisfranc ligament and the dorsal cuneometatarsal ligament. DESIGN: Cadaveric study in normal feet. SETTING: Biomechanics laboratory. PATIENTS OR PARTICIPANTS: Twelve fresh-frozen cadaveric feet were studied. INTERVENTION: The Lisfranc and dorsal cuneometatarsal ligaments were dissected, dimensions measured, and material properties determined with a servohydraulic MTS machine on bone-ligament-bone preparations. MAIN OUTCOME MEASUREMENTS: Stiffness, strain, stress, modulus, failure load, ligament length, width, thickness, and cross-sectional area were determined. RESULTS: Dorsal ligament stiffness was 66.3+/-18.3 newtons per millimeter and the Lisfranc ligament stiffness was 189.7+/-57.2 newtons per millimeter. The failure load of the dorsal ligament averaged 150.7+/-33.1 newtons and for the Lisfranc ligament, 368.8+/-126.8 newtons. CONCLUSIONS: The stiffness and load to failure of the dorsal cuneometatarsal ligament were much higher than anticipated, which indicates that it contributes significantly to stabilizing the second metatarsal to the first cuneiform.

Aged↗
PubMed1994

Elastin in the human posterior longitudinal ligament and spinal dura. A histologic and biochemical study.

STUDY DESIGN: A histologic and biochemical study of elastin in the posterior longitudinal ligament and spinal dura was performed using autopsy cadavers. OBJECTIVE: To provide a rationale for resiliency of the PLL and the spinal dura. SUMMARY OF BACKGROUND DATA: Among the spinal ligaments, the nuchal ligament and the ligamentum flavum have a very high elastin content, and some biochemical and morphologic studies of these ligaments have been published. No reports on the elastin content in the posterior longitudinal ligament or spinal dura have been published. METHODS: Specimens of the posterior longitudinal ligament and the dura collected from three cadavers were studied histologically. For quantitative analysis of elastin and collagen, the posterior longitudinal ligament specimens were collected from 22 cadavers and the dura specimens from 20 cadavers. Elastin was extracted using the hot alkali method of Lansing et al. RESULTS: The elastic fibers in the posterior longitudinal ligament generally were arranged parallel in the cephalocaudal direction, whereas the fibers in the spinal dura had a more multidirectional arrangement. The elastin content of the posterior longitudinal ligament averaged 7.3% of the total dry weight and that of the spinal dura was 7.1% for the ventral aspect and 13.8% for the dorsal aspect. The elastin content of the spinal dura was about two times higher in all dorsal specimens than in the corresponding ventral specimens. The elastin content of the lower thoracic region was higher than that of any other region. The amino acid composition of the elastin in the posterior longitudinal ligament and spinal dura was similar to that previously determined in other spinal ligaments.

Aged↗
PubMed1995

Lesions of the alar ligaments. In vivo and in vitro studies with magnetic resonance imaging.

STUDY DESIGN: This study analyzed anatomic characteristics of the alar ligaments and the possibility of imaging them with magnetic resonance imaging. Also determined was whether artificial ruptures of the alar ligament can be recognized experimentally. OBJECTIVE: To determine the ability of magnetic resonance imaging to visualize normal, torn, resected alar ligaments. SUMMARY OF BACKGROUND DATA: There are no studies about computed tomography or magnetic resonance imaging findings of alar ligaments and after anatomic sections. Direct visualization of the complete ligament is not possible for computed tomography. No precise diagnostic method for showing a ruptured alar ligaments has been described. Magnetic resonance imaging seems to be the method of choice for distinguishing between normal and pathologic soft tissue. METHODS: Fifteen specimens from accident victims underwent anatomic dissection. In addition, ligaments from three groups were examined: 1) eight volunteers, 2) seven patients, and 3) 17 fresh cadaveric specimen before anatomic exploratory dissection. In seven of these specimens, one ligament was cut to simulate an artificial disruption and magnetic resonance imaging was repeated. RESULTS: Lesions of the alar ligaments were found in four of 15 prepared specimens. Using magnetic resonance imaging, the alar ligaments could be identified in all volunteers, patients, and specimen except one. No ruptures were found in the 17 specimens. Of the seven resected specimens, all cuts could be demonstrated by magnetic resonance imaging. CONCLUSION: Magnetic resonance imaging is useful for showing lesions of the alar ligaments because of a high soft tissue contrast, plane independence imaging, possibility of functional scans, and secondary reconstruction from three-dimensional data sets.

Atlanto-Occipital Joint↗
PubMed1997

Bone mineral density in patients with ossification of the posterior longitudinal ligament. Minimal decrease of bone mineral density with aging.

STUDY DESIGN: Bone mineral density of individuals with ossification of the posterior longitudinal ligament and that of normal people was determined by dual-energy x-ray absorptiometry. OBJECTIVES: To determine whether bone mineral density in the people with ossification of the posterior longitudinal ligament is higher than that in normal individuals even in body parts other than the spine, and to evaluate the relation between bone mineral density and age in patients with ossification of the posterior longitudinal ligament. SUMMARY OF BACKGROUND DATA: It is unknown whether the bone mineral density of patients with ossification of the posterior longitudinal ligament is greater in body parts other than the spine. If so, it provides a basis for the theory that certain systemic factors are involved in the pathogenesis of ossification of the posterior longitudinal ligament. Because bone mineral density decreases physiologically after middle age, the influence of age must be considered in evaluating bone mineral density. METHODS: In the rib area and upper and lower limb areas, which are not affected by ossification of the spinal ligament, bone mineral density of 45 men with ossification of the posterior longitudinal ligament of the cervical spine was compared with that of 25 men without ossification of the posterior longitudinal ligament (normal group). RESULTS: Bone mineral density was higher in the group with ossification of the posterior longitudinal ligament in each part and significantly higher in the rib and lower limb areas (rib: P < 0.01, lower limb: P < 0.05). The age-related decrease was significantly less in the group with ossification of the posterior longitudinal ligament (rib: P < 0.01, upper limb: P < 0.05, lower limb: P < 0.01). CONCLUSIONS: Systemic factors that increase bone mineral density appear to be involved in the pathogenesis of ossification of the posterior longitudinal ligament, and these factors may be activated after middle age.

Absorptiometry, Photon↗
PubMed2003

Radiculopathy due to ossification of the yellow ligament at the lower lumbar spine.

STUDY DESIGN: A case report. OBJECTIVES: To report a rare case of a 27-year-old female with ossification of yellow ligament at the lower lumbar spine presenting radiculopathy with a drop foot. SUMMARY OF BACKGROUND DATA: The majority of cases of ossification of yellow ligament occur at the lower third of the thoracic or the thoracolumbar spine. There are only a few reports of ossification of yellow ligament in the lumbar spine and radiculopathy due to ossification of yellow ligament at L4-L5 and L5-S1 levels is very uncommon. METHODS: A 27-year-old female with a prior fracture of posterior ring apophysis of L5 presented with leg pain and a drop foot. Magnetic resonance imaging demonstrated stenosis with compression of the cauda equina at the L4-L5 and L5-S1 levels. RESULTS: Decompressive laminectomy of L5 and removal of the ossified yellow ligaments were performed. Histologic examination of en bloc specimen of ossification of yellow ligament revealed degenerative changes of the elastic fibers in the yellow ligament with adjacent chondrosis and ossification. The patient's severe leg pain disappeared completely, although the extent of the drop foot had not fully recovered at the final follow-up examination. CONCLUSIONS: The mechanism of ossification of yellow ligament in the present case was unclear. The patient did not have any previous generalized disorders besides the history of a ring apophysial fracture or any family history of treatment for ossification of the posterior longitudinal ligament or ossification of yellow ligament. Therefore, localized mechanical stress might have influenced the development of ossification of yellow ligament at lower lumbar spine.

Adult↗
PubMed2005

Extraforaminal ligament attachments of human lumbar nerves.

STUDY DESIGN: An anatomic study of the extraforaminal attachments of the lumbar spinal nerves was performed using human lumbar spinal columns. OBJECTIVES: To identify and describe the existence of ligamentous structures at each lumbar level that attach lumbar spinal nerves to structures at the level of the extraforaminal region. SUMMARY OF BACKGROUND DATA: During the last 120 years, several mechanisms to protect the spinal nerve against traction have been described. All these structures involved are located in the spinal canal, proximal to the intervertebral foramen. METHODS: Five embalmed human lumbar spines (T12-S1) were used. Bilaterally, the extraforaminal region was dissected to describe and measure anatomic structures and their relationships. Histology was performed with staining on the sites of attachment and along the ligament. RESULTS: The levels T12-L2 show bilaterally 2 ligaments, a superior extraforaminal ligament and an inferior extraforaminal ligament. The superior extraforaminal ligament emerges from the joint capsule of the facet joints and inserts in both, the intervertebral disc and the ventral crista of the intervertebral foramen, passing the spinal nerve laterally. In one specimen on level L2-L3, the superior extraforaminal ligament is not attached to the spinal nerve. The inferior extraforaminal ligament emerges from the intervertebral disc, passing the nerve medially and attaching the spinal nerve. At the levels L2-L5, the inferior extraforaminal ligaments are only attached to the intervertebral disc, not to the joint capsule. Histologically, the ligaments consisted of mainly collagenous structures. CONCLUSION: Ligamentous connections exist between lumbar extraforaminal spinal nerves and nearby structures.

Aged, 80 and over↗
PubMed2003

US of the anterior bundle of the ulnar collateral ligament: findings in five cadaver elbows with MR arthrographic and anatomic comparison--initial observations.

PURPOSE: To characterize the ultrasonographic (US) appearance of the anterior bundle of the ulnar collateral ligament of the elbow by comparing US images with magnetic resonance (MR) arthrograms and anatomic slices. MATERIALS AND METHODS: The ulnar collateral ligament in four cadavers (eight elbows) was blindly evaluated with US by one musculoskeletal radiologist with experience in musculoskeletal US. These results were compared with standard arthrograms, MR arthrograms, and anatomic slices by consensus reading of two musculoskeletal radiologists. The criteria for an abnormal ulnar collateral ligament included contrast material extension into the ligament or fiber discontinuity, as documented by MR arthrography and anatomic slices. RESULTS: Standard arthrography, MR arthrography, and anatomic slices demonstrated the ulnar collateral ligament to be unequivocally normal in three specimens and abnormal in two. The remaining three elbows did not meet the criteria for classification as either normal or abnormal, and thus they were excluded from the study. With US, the normal ulnar collateral ligament was fibrillar and hyperechoic between the medial epicondyle and proximal ulna. In the two abnormal cases, abnormal hypoechogenicity and ligament fiber disruption were noted. In addition, the proximal aspect of the ulnar collateral ligament varied from a cordlike structure to a broad attachment to the undersurface of the medial epicondyle with variable fat. CONCLUSION: In this small sample, the anterior bundle of the ulnar collateral ligament is identified with US by its hyperechoic and compact fibrillar echotexture. The proximal attachment of the ulnar collateral ligament has a variable appearance. Hypoechogenicity and fiber disruption indicated ulnar collateral ligament abnormality.

Aged↗
PubMed2006

The lumbar interspinous ligaments in humans: anatomical study and review of the literature.

In textbooks of human anatomy and atlases of spinal surgery, the lumbar interspinous ligaments are described and illustrated in various and often conflicting ways. Thirty-four lumbar vertebral columns (19 males, 15 females, range 17-92 years old), sampled at autopsy, were studied by dissection and macroscopic analysis. The orientation of the fibre bundles was evaluated in the sagittal plane by tracing a reference line parallel to the cranial border of the spinous process, and the degree of bundle tilting with reference to this line was measured in the ventral, middle and dorsal parts of the ligament. Histological and immunohistochemical (anti-S100) studies of the ligaments, on sagittal, frontal, and transversal planes, were also carried out. In vivo radiological validation was performed in 25 patients by MR and CT imaging. Macroscopically, the interspinous ligaments are consistently composed of bundles of fibres arranged in a characteristic pattern. Together, they present an oblique orientation from anterior to posterior in a caudal-cranial direction. In their ventral part the bundles form a slight curve with a posterior-inferior concavity. In the middle part, the bundles are thicker and arranged in an italic S shape with a mean degree of tilting of 52 +/- 14, 21 +/- 12 and 50 +/- 17 in the anterior, intermediate and posterior subzones of the L2-L3 ligaments and of 32 +/- 14, 11 +/- 9 and 18 +/- 11 in the anterior, intermediate and posterior subzones of the L4-L5 level. The dorsal part consists of obliquely ascending bundles of fibres mostly converging in the supraspinous ligament. Histologically, these ligaments are mainly composed of collagen fibres, whereas the elastic fibres are ubiquitous, although mostly concentrated in the ventral part, which is closely linked to the yellow ligament. The interspinous ligament is well supplied by small blood vessels and sensory nerves, the latter particularly in its dorsal part and on its lateral surfaces. According to collected data, the structure of the interspinous ligaments reflects their function, i.e., the italic S-shaped course of the fibrous bundles represents an available reserve of length in a poorly elastic ligament.

Adolescent↗
PubMedDate not supplied

The influence of a cyclooxygenase-1 inhibitor on injured and uninjured ligaments in the rat.

BACKGROUND: Results of previous studies have shown that piroxicam, a cyclooxygenase-1-2 inhibitor, improves the strength of healing ligaments, whereas celecoxib, a cyclooxygenase-2 inhibitor, impairs ligament healing. HYPOTHESIS: The selective cyclooxygenase-1 inhibitor, SC-560, will improve the strength of ligament healing in an in vivo rat model. STUDY DESIGN: Controlled laboratory study. METHODS: Eighty male Sprague-Dawley rats underwent surgical transection of their medial collateral ligament. Postoperatively, 20 rats were given SC-560 at a low dose and 20 at a high dose for the first 6 days of recovery; the other 40 received a normal diet. The animals were sacrificed 14 days later, and both the injured and uninjured ligaments were mechanically tested to failure in tension. RESULTS: No significant differences in the strength of injured ligaments were found between drug and placebo treatment. However, the contralateral uninjured ligaments in the SC-560-treated groups failed at 27% higher energy and 22% higher load. CONCLUSIONS: This cyclooxygenase-1 inhibitor did not improve the strength of ligament healing but did significantly improve the strength of the contralateral uninjured ligament. CLINICAL RELEVANCE: A pure cyclooxygenase-1 inhibitor is probably not indicated as a positive influence on ligament healing but might provide benefits in ligament injury prevention.

Animals↗
PubMed2005

The annular ligament: an anatomical study.

BACKGROUND: Despite documentations of ligamentous structures of the elbow, the anatomy and clinical and functional importance of the annular ligament has not been comprehensively defined in the orthopaedic literature. HYPOTHESIS: The annular ligament is an important component of both the proximal radioulnar and humeroradial joints, as well as an important component of the neighboring muscles and ligaments. STUDY DESIGN: Descriptive laboratory study. MATERIALS AND METHODS: To investigate the annular ligament and its relationship with neighboring structures, macroscopic and microscopic dissections were performed on both upper extremities of 30 cadavers (12 female and 18 male) fixed in 10% formaldehyde and on 1 upper extremity of a fresh cadaver (male). RESULTS: The distal ulnar insertion of discrete fibers on the supinator crest was defined as the inferior oblique band of the annular ligament, and the proximal insertion of the annular ligament was defined as the superior oblique band of the annular ligament. These patterns were noted in all specimens. It was difficult to distinguish the fibers of the supinator muscle in every specimen because they were intimately fused with the fibers of the annular ligament. CONCLUSIONS: The superior and inferior oblique bands of the annular ligament attached proximally and distally onto the ulna, thus helping to secure the annular ligament in place.

Cadaver↗
PubMed2005

Biomechanical measures of neuromuscular control and valgus loading of the knee predict anterior cruciate ligament injury risk in female athletes: a prospective study.

BACKGROUND: Female athletes participating in high-risk sports suffer anterior cruciate ligament injury at a 4- to 6-fold greater rate than do male athletes. HYPOTHESIS: Prescreened female athletes with subsequent anterior cruciate ligament injury will demonstrate decreased neuromuscular control and increased valgus joint loading, predicting anterior cruciate ligament injury risk. STUDY DESIGN: Cohort study; Level of evidence, 2. METHODS: There were 205 female athletes in the high-risk sports of soccer, basketball, and volleyball prospectively measured for neuromuscular control using 3-dimensional kinematics (joint angles) and joint loads using kinetics (joint moments) during a jump-landing task. Analysis of variance as well as linear and logistic regression were used to isolate predictors of risk in athletes who subsequently ruptured the anterior cruciate ligament. RESULTS: Nine athletes had a confirmed anterior cruciate ligament rupture; these 9 had significantly different knee posture and loading compared to the 196 who did not have anterior cruciate ligament rupture. Knee abduction angle (P<.05) at landing was 8 degrees greater in anterior cruciate ligament-injured than in uninjured athletes. Anterior cruciate ligament-injured athletes had a 2.5 times greater knee abduction moment (P<.001) and 20% higher ground reaction force (P<.05), whereas stance time was 16% shorter; hence, increased motion, force, and moments occurred more quickly. Knee abduction moment predicted anterior cruciate ligament injury status with 73% specificity and 78% sensitivity; dynamic valgus measures showed a predictive r2 of 0.88. CONCLUSION: Knee motion and knee loading during a landing task are predictors of anterior cruciate ligament injury risk in female athletes. CLINICAL RELEVANCE: Female athletes with increased dynamic valgus and high abduction loads are at increased risk of anterior cruciate ligament injury. The methods developed may be used to monitor neuromuscular control of the knee joint and may help develop simpler measures of neuromuscular control that can be used to direct female athletes to more effective, targeted interventions.

Adolescent↗
PubMed2005

Anatomical reconstruction of the lateral ligaments of the ankle with a gracilis autograft: a new technique using an interference fit anchoring system.

BACKGROUND: Few anatomical and minor invasive procedures have been reported for surgical reconstruction of the lateral ligaments to treat lateral instability of the ankle. Furthermore, there are no standards according to which ligaments should be reconstructed. HYPOTHESIS: A new technique for anatomically reconstructing the lateral ligaments of the ankle using an interference fit anchoring system and determining which ligaments need to be reconstructed according to the results of standard stress radiography of the talocrural and subtalar joints will be effective for treating lateral instability of the ankle. STUDY DESIGN: Case series; level of evidence, 4. METHODS: Twenty-one patients with lateral instability of the ankle underwent surgery using the proposed interference fit anchoring system. Standard stress radiographs of the subtalar joint were performed, and if the talocalcaneal angle was less than 10 degrees , only the anterior talofibular ligament was reconstructed; if there was a 10 degrees or greater opening of the talocalcaneal angle, both the anterior talofibular ligament and the calcaneofibular ligament were reconstructed. RESULTS: In the 17 patients who received only the anterior talofibular ligament reconstruction, the mean talar tilt angle on standard stress radiography of the talocrural joint was 14.5 degrees +/- 1.7 degrees before surgery and 2.6 degrees +/- 0.8 degrees 2 years after surgery (P < .0001). For the 4 patients who had both the anterior talofibular ligament and calcaneofibular ligament reconstructed, the mean talar tilt angle was 16.5 degrees +/- 1.5 degrees before surgery and 3.0 degrees +/- 0.5 degrees 2 years after surgery (P = .0015). The overall mean talocalcaneal angle on standard stress radiography of the subtalar joint was 11.3 degrees +/- 1.4 degrees before surgery and 3.5 degrees +/- 0.8 degrees 2 years after surgery (P = .0060). CONCLUSION: The proposed system has several advantages, including anatomical reconstruction with normal stability and range of motion restored, the need for only a small incision during the reconstruction, and sufficient strength at the tendon graft-bone tunnel junction, in comparison with the tension strength of the lateral ligaments of the ankle.

Adolescent↗
PubMed2005

Effects of local administration of vascular endothelial growth factor on properties of the in situ frozen-thawed anterior cruciate ligament in rabbits.

BACKGROUND: In the autogenous tendon for anterior cruciate ligament reconstruction, intrinsic fibroblasts are necrotized immediately after surgery, and repopulation and revascularization occur. Vascular endothelial growth factor is considered to be a potent mediator of angiogenesis. HYPOTHESIS: An application of vascular endothelial growth factor significantly enhances angiogenesis in the in situ frozen anterior cruciate ligament, and the application significantly affects mechanical properties of the in situ frozen anterior cruciate ligament. STUDY DESIGN: Controlled laboratory study. METHODS: Right anterior cruciate ligaments from 66 rabbits underwent the freeze-thaw treatment, and animals were then divided into 3 groups. Group I served as a freeze-thaw but otherwise untreated control. In group II, 0.2 mL phosphate-buffered saline alone was applied. In group III, 30 mug vascular endothelial growth factor was applied. The groups were compared on the basis of histologic revascularization examinations using the Chalkley score, an indicator of the microvessel density, and mechanical evaluations, which included the anterior-posterior translation of the tibia relative to the femur during +/- 10 N of anterior-posterior load and the mechanical properties of the anteromedial bundle of the anterior cruciate ligament. RESULTS: Group III's Chalkley score was significantly greater than that of groups I and II. The tensile strength and the tangent modulus of anterior cruciate ligaments in groups I, II, and III were significantly lower than those of a normal anterior cruciate ligament, although there were no significant differences among groups I, II, and III. CONCLUSION: Vascular endothelial growth factor, as administered in this study, significantly promoted angiogenesis in the devitalized anterior cruciate ligament with in situ freeze-thaw treatment, but it did not affect the mechanical properties of the in situ frozen-thawed anterior cruciate ligament in the rabbit model. CLINICAL RELEVANCE: An application of the recombinant anterior cruciate ligament is a potential future strategy to enhance revascularization of the autograft in anterior cruciate ligament reconstruction.

Animals↗
PubMed2005

Structural properties of lateral collateral ligament reconstruction at the fibular head.

BACKGROUND: Anatomical reconstruction of a ruptured lateral collateral ligament using allograft tissue secured within the fibular head with an interference screw has been described. HYPOTHESIS: Interference fixation at the fibular head does not reproduce the strength of the intact ligament. STUDY DESIGN: Controlled laboratory study. METHODS: Ten intact lateral collateral ligaments were tested to failure. The distal fixation of 11 ligaments reconstructed with a graft including a bone plug and 11 ligaments reconstructed with a graft without a bone plug were also tested. RESULTS: The reconstructed ligaments consistently failed at the fibular head. The intact specimens predominately failed through ligament rupture. The mean strength and stiffness values were 460 +/- 163 N and 82 +/- 25 N/mm, respectively, for the intact ligaments, 113 +/- 40 N and 36 +/- 10 N/mm, respectively, for reconstruction with a bone plug, and 135 +/- 81 N and 34 +/- 14 N/mm, respectively, for reconstruction without a bone plug. The strength and stiffness were significantly (P < .05) greater for the intact ligaments than for either reconstruction group. The variation in strength was significantly larger for reconstruction without a bone plug than for reconstruction with a bone plug. CONCLUSION: Tension applied to lateral collateral ligaments reconstructed using fibular interference fixation should be limited immediately after surgery. Soft tissue fixation should be employed with care because of the inconsistency in the failure strength. CLINICAL RELEVANCE: Although fibular interference fixation is increasingly being described in the literature, the properties of reconstructed lateral collateral ligaments have not previously been quantified.

Bone Screws↗
PubMed2006

Anatomical posterior cruciate ligament transplantation: a biomechanical analysis.

BACKGROUND: Although current techniques of posterior cruciate ligament reconstruction may successfully stabilize the posterior cruciate ligament-deficient knee, no studies have demonstrated restoration of intact-knee kinematics. HYPOTHESIS: Posterior cruciate ligament transplantation will successfully restore posterior stability and kinematics to the posterior cruciate ligament-deficient knee. STUDY DESIGN: Controlled laboratory study. METHODS: Seven pairs (donor/recipient) of size-matched cadaveric knees underwent a novel technique for posterior cruciate ligament transplantation. The grafts were fixed at the femoral origin and tibial insertion using an inlay technique with rigid fixation. The knees were tested in the intact (intact group), posterior cruciate ligament-deficient (deficient group), and posterior cruciate ligament-transplanted (transplant group) states. A 3-dimensional electromagnetic tracking system during an active knee extension and passive knee flexion maneuver was used to quantify kinematics, specifically looking at femoral rollback. KT ligament arthrometry was used to quantify posterior stability at the quadriceps neutral angle (70 degrees ). RESULTS: For femoral rollback, the intact versus deficient groups was significantly different (P = .045) as was deficient versus transplant groups (P = .008) but not intact versus transplant groups. Similar differences were noted with the measurements of posterior stability (P < .001). Total posterior laxity between the intact versus deficient groups was significantly different (means, 1.32 mm vs 11.1 mm; P < .0001), as was deficient versus transplant groups (means, 11.1 mm vs 2.04 mm; P < .126) but not intact versus transplant groups. CONCLUSION: In a posterior cruciate ligament-deficient cadaveric model, we demonstrated the technical feasibility and efficacy of posterior cruciate ligament transplantation for restoring femoral rollback and posterior stability at the quadriceps neutral angle. CLINICAL RELEVANCE: Future studies in posterior cruciate ligament reconstruction should not only address stability but also restoration of normal knee kinematics in assessing the success of a given technique.

Biomechanical Phenomena↗
PubMed1988

Strain in the lateral ligaments of the ankle.

Strain was measured in the normal anterior talofibular ligament (ATF) and the calcaneofibular ligament (CF) using Hall effect strain transducers in five cadaveric ankles. These measurements were made in both ligaments with the ankle in neutral position and with the foot moving from 10 degrees dorsiflexion to 40 degrees plantarflexion in an apparatus that permits physiologic motion. The ankle ligaments were then tested with the foot placed in six different positions that combined supination, pronation, external rotation, and internal rotation. In the neutral position, through a range of motion of 10 degrees dorsiflexion to 40 degrees plantarflexion, the anterior talofibular ligament underwent an increasing strain of 3.3%. No significant strain increase was found with internal rotation. The only significant difference from the strains at the neutral position was in external rotation, which decreased strain 1.9%. In all positions, increased strain occurred with increased plantarflexion. The calcaneofibular ligament was essentially isometric in the neutral position throughout the flexion arc. The calcaneofibular ligament strain was significantly increased by supination and external rotation. However, with increasing plantarflexion in these positions, the strain in the calcaneofibular ligament decreased. Therefore, plantarflexion has a relaxing effect on the calcaneofibular ligament. Thus, the anterior talofibular and calcaneofibular ligaments are synergistic, such that when one ligament is relaxed, the other is strained and vice versa.

Adult↗
PubMed1998

Anatomy of the collateral ligaments of the human ankle joint.

Damage to the collateral ligaments of the ankle is relatively common, particularly the lateral ligaments; therefore, it is important to be aware of the detailed anatomy and frequency of variation of the individual ligaments. Only two reports of collateral ligaments dimensions were found in the literature, neither of which considers all of the individual components of the collateral ligament complex. Osteoligamentous preparations of the collateral ligaments of 40 ankles from 20 cadavers of European Caucasian origin were studied, from which mean values for the length and width of the individual components were determined, together with their frequency of occurrence. For the collateral ligaments of the ankle as a whole, the ligamentous dimensions determined in this study are similar to those reported previously. The data presented in this study are, therefore, a valuable addition to the small pool of data that exists concerning the dimensions of the collateral ligaments of the human ankle joint. These data may be of value when considering surgical repair or reconstruction of traumatized collateral ligaments, especially because any undue foreshortening of the ligaments may reduce the range of motion possible at either the ankle or subtalar joints, or both. It is possible that in extreme cases, such a reduction in the range of motion may modify gait patterns and the transmission of stresses across the joints of the foot and lower limb.

Aged↗
PubMed1993

Ligament forces at the knee during isometric quadriceps contractions.

A mathematical model of the knee in the sagittal plane was used to investigate the ligament forces resulting when a posteriorly directed external force, applied to the tibia, resists extension of the knee under increasing isometric quadriceps contractions. The model is based on simple geometric representations of the bones, ligaments and muscles at the knee. An elementary mechanical analysis was used to predict which ligament, the anterior or posterior cruciate, was loaded at a given flexion angle and known line of action of the external force. Ligament force, as a proportion of the external force, was calculated first assuming the ligaments to be represented by single, inextensible lines. Modelling the ligaments as continuous arrays of extensible fibres then showed that tibio-femoral translations and ligament forces increased non-linearly with increasing muscle forces and approached asymptotic values which depended on flexion angle. In most positions of the joint, the calculated asymptotic ligament force values were less than the reported ultimate strength of human ligament, despite quadriceps forces of over three times body weight. The possibility of these asymptotic values of ligament force may explain why, at certain flexion angles, large forces can be developed by the muscles at the knee without ligament rupture.

Biomechanical Phenomena↗