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PubMed2000

The interspinous ligament of the lumbar spine. Magnetic resonance images and their clinical significance.

STUDY DESIGN: A preliminary study of magnetic resonance features of the interspinous ligament in degenerative lumbar spine. OBJECTIVES: To classify the magnetic resonance imaging features of the interspinous ligaments in relation to the patient's age, disc degeneration, and radiographic instability. Magnetic resonance imaging also was correlated with the histologic findings of the interspinous ligaments. SUMMARY OF BACKGROUND DATA: As reported, rupture of the interspinous ligament frequently is found in the degenerative lumbar spine. However, little information is available in the literature on imaging assessment of the interspinous ligament in degenerative lumbar disorders. METHODS: In this study, 24 interspinous ligaments at L1-L2 or L2-L3 from 15 patients with nondegenerated discs were selected to represent normal magnetic resonance features of the interspinous ligament, and 38 patients with the mean age of 49 years underwent functional radiography and magnetic resonance imaging. The magnetic resonance features of the interspinous ligament were classified into five categories according to their signal intensities: Type 1A (low intensity on T1- and T2-weighted images without hypertrophy of the spinal process); Type 1B (same signal pattern as in Type 1A with hypertrophy of spinal process); Type 2 (low intensity on T1- and high intensity on T2-weighted images); Type 3 (high intensity on T1-weighted images); and Type 4 (others). Seven patients with variable patterns of the interspinous ligament were selected to undergo histologic examinations. RESULTS: Of the interspinous ligaments considered normal, 80% were classified as Type 1A. There were 14 Type 1A, 30 Type 1B, 19 Type 2, 16 Type 3, and 20 Type 4 ligaments. The mean age and disc degeneration grade of the patients with the Type 1B ligaments was significantly higher. Instability was found to be associated with Type 2 interspinous ligaments (7 of 19), whereas instability rarely was noted in Types 1A (1 of 14) and 1B (1 of 30) ligaments. The histologic examination revealed that chondrometaplasia and necrotization of fiber bundle predominated in Type 1B, proliferation of cells and vascular invasion in Type 2, fatty degeneration in Type 3 ligaments. CONCLUSIONS: The magnetic resonance imaging characteristics may be helpful in assessing normal or pathologic changes in the interspinous ligaments.

Adolescent↗
PubMed1990

Elongation and forces of ankle ligaments in a physiological range of motion.

The purposes of this study were: (1) to measure the distances between the insertion sites of selected ankle ligament fibers, (2) to measure the force-elongation characteristics of isolated bone-ligament-bone preparations, and (3) to relate the force measurements to angular positions of the ankle. The findings can be used to discuss clinically the correlation between possible ligament injuries and associated foot movement. Three fresh cadaveric ankles were dissected to expose the anterior talofibular ligament, the calcaneofibular ligament, and the superficial deltoid ligament. The ankles were first mounted on a fixture, and insertion to insertion distances of the ligament fibers were measured for selected positions of the ankle/subtalar joint. Bone-ligament-bone preparations were then removed, returned to their anatomical length and uniaxial force-extension testing was performed. The forces in each ligament were recorded for distances corresponding to those measured in situ for various ankle positions. These results allowed: (1) estimation of the forces in these three ligaments in various ankle positions, (2) identification of positions where ligaments were carrying no force, and (3) identification of positions where they carry large forces. The clinical analysis reveals that the anterior talofibular ligament is sensitive to excessive plantarflexion or dorsiflexion, the calcaneofibular ligament is sensitive to excessive inversion or eversion as well as dorsiflexion or plantarflexion, and that the deltoid ligament appears to be sensitive to plantarflexion, external rotation, and eversion. The fact that all three ligaments tested demonstrated different ranges of tension supports the view that there are optimal positions for testing ankle ligament integrity.

Adult↗
PubMed2003

[Sclerotic changes in ossicular ligaments in human temporal bone pathology].

When tympanoplasty is performed for conductive hearing loss due to otitis media, hearing recovery may not be as good as anticipated preoperatively. Sclerotic changes may therefore exist in the conduction system of the middle ear. To clarify the relationship between middle ear inflammation and sclerotic changes of middle ear sound conduction, particularly of the ossicular ligaments, specimens of human temporal bones were studied. Histology of the anterior malleal ligament, posterior incudal ligament, and stapediovestibular ligament was examined in 636 ears from 367 individuals (postmortem) ranging from infancy to 90 years old and without blood disease, neoplasm, anomaly, or cholesteatoma. Only small numbers of acute and subacute inflammatory were identified, but sclerotic changes in ligaments were compared between normal and chronically inflamed ears. In anterior malleal and posterior incudal ligaments, the severity of sclerotic hyalinization and calcification increased with age in normal ears, but sclerotic changes in chronically inflamed ears were more severe than in normal ears and displayed a reduced association with age. Conversely, sclerosis of the stapediovestibular ligament was less severe than that of the anterior malleal and posterior incudal ligaments in both normal and chronically inflamed ears, and displayed a reduced relationship with age. The sclerotic changes apparent in the anterior malleal and posterior incudal ligaments therefore seem to be more readily influenced by inflammation than by age. Sclerotic changes of the stapediovestibular ligament are not as severe as those of anterior malleal and posterior incudal ligaments. For cases in which tympanoplasty of inflamed ears is planned, mobility of the anterior malleal and posterior incudal ligaments should be tested independent of testing of the stapediovestibular ligament. When mobility of anterior malleal and posterior incudal ligaments is not as good as mobility of the stapediovestibular ligament, surgical modification of the anterior malleal and posterior incudal ligaments may be advisable.

Adolescent↗
PubMed1985

Stability of the ankle joint. Analysis of the function and traumatology of the ankle ligaments.

The purpose of this study was to elucidate the function of the ligamentous structures of the ankle joint, the traumas in which they may rupture, and the types of instability caused by such ruptures. Most previous experimental investigations on the function of ankle ligaments have been performed on osteoligamentous preparations either by forcing a movement in the joint into more or less well-defined directions and observing the resulting injuries or else by cutting ligaments in various combinations and describing the resulting instability. As a rule, this has been done without inducing the increased mobility by a defined torque and without being able to demonstrate the instability continuously in all degrees of dorsi- or plantar flexion. On the basis of these previous studies, the anterior talofibular ligament appears to limit internal rotation, while its role in adduction of the talus has not been clarified. The calcaneofibular ligament per se does not seem to be a factor in adduction. True, there is not complete agreement in this respect, and a few authors have been able to rupture this ligament in isolation by forced adduction. The posterior talofibular ligament seems to restrict dorsiflexion, and perhaps it plays a role, in conjunction with the calcaneofibular ligament, in adduction when the ankle joint is in dorsiflexion. The anterior tibiofibular ligament, and the distal tibiofibular structures on the whole, are assumed to limit external rotation, but it has not been clarified whether they influence adduction and abduction in the ankle joint. Little has been reported about the individual structures which make up the deltoid ligament, as most authors have not distinguished them from each other. However, in combination with the anterior talofibular ligament, the tibiotalar ligament seems to limit the translatory forward gliding of the talus - the so-called anterior drawer sign - and together they presumably inhibit plantar flexion. It has not been possible to find any description of the function of the intermediate tibiotalar ligament, while the posterior tibiotalar ligament has been reported by one author to inhibit internal rotation. Judging by the literature, the function of the tibiocalcaneal ligament seems comprehensive, since it is reported to limit external rotation, dorsiflexion, as well as plantar flexion. The present investigations were divided into three phases: Phase 1 was concerned with elucidating the correlation of injuries to the lateral collateral ligaments to internal rotatory instability, talar tilt, and the anterior drawer sign.(ABSTRACT TRUNCATED AT 400 WORDS)

Ankle Joint↗
PubMed1994

The effects of nerve injury on ligament healing in a rat model.

The presence of an intact nerve supply is important in the regeneration of injured tissue in some animals. It has not been determined whether an intact nerve supply is important in ligamentous healing. The authors hypothesize that the nerve supply of a ligament might have a significant effect on its healing. The purpose of this paper was to determine whether injury to the nerve supply of the medial collateral ligament in a rat model results in poor ligament healing (which would suggest that intact nerve supply enhances ligament repair). Clinically, such a finding would demonstrate the importance of avoiding injury to nerve-ligament systems in reparative ligament surgery. Twenty three rats underwent complete bilateral dissection of the major nerves supplying the medial collateral ligament, and each ligament was transected at the level of the tibial tuberosity. The major nerve supplies of the experimental ligaments were destroyed by segmental excision, either distally at the medial articular nerves or proximally at the saphenous nerve, while the control ligament's nerve supplies were left intact. The rats were euthanized at 12 days, and each medial collateral ligament was tested biomechanically using a hydraulic materials testing machine. This time point was chosen because the rat ligament transection site heals rapidly, causing the ligament to avulse from its tibial insertion instead of rupturing at the transection site at later time points. This rat medial collateral ligament injury model has shown statistically significant differences in healing at this time point in numerous experiments evaluating the effects of other variables on ligament healing.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1996

Extrasynovial spaces of the cruciate ligaments: anatomy, MR imaging, and diagnostic implications.

OBJECTIVE: The purpose of our study was to define the anatomy of the extrasynovial space that cruciate ligaments occupy by examining the pattern on MR imaging of normal fluid distribution in the joints around the cruciate ligaments and correlating this distribution with histologic analysis of synovial reflections around the cruciate ligaments. MATERIALS AND METHODS: MR images of five cadaveric knees were obtained serially after larger and larger amounts of contrast material were injected into the joint space. The patterns of fluid distribution around cruciate ligaments were noted. In two other cadaveric knees, the synovial sheath around the anterior cruciate ligament was injected directly with contrast material under CT guidance. Anatomic and histologic correlation was made with findings on corresponding MR images. RESULTS: The pattern of fluid distribution is bounded by the synovial reflections around cruciate ligaments. When maximum joint distention is achieved, fluid almost surrounds the cruciate ligaments. The area without fluid is a triangular space between the anterior and posterior cruciate ligaments that appears on the midsagittal image. This triangular space of the cruciate ligaments is an extrasynovial space within which both the anterior cruciate ligament and the posterior cruciate ligament reside. CONCLUSION: The overlying synovial membrane of the cruciate ligaments does not normally allow joint fluid to enter the substance of the ligaments or the triangular space of the cruciate ligaments. Therefore, fluid collections seen on MR imaging in these extrasynovial spaces or structures likely arises from injury to the cruciate ligaments.

Adult↗
PubMed1995

Comparative study of the size and shape of human anterior and posterior cruciate ligaments.

As an important step toward determination of the function of cruciate ligaments, the cross-sectional shapes and areas of the anterior cruciate, posterior cruciate, and meniscofemoral ligaments were evaluated in situ within the same knee with use of a laser micrometer system. Measurements were made in eight human cadaveric knees at five levels along the midsubstance of each ligament, with the knee at 0 degree, 30 degrees, 60 degrees, and 90 degrees of flexion. The posterior cruciate ligament was found to be widest in the medial-lateral direction, whereas the anterior cruciate ligament usually was larger in the anterior-posterior direction. The cross-sectional shapes of the anterior cruciate ligament generally were noted to be more circular along the entire midsubstance than were those of the posterior cruciate ligament. In contrast, the cross-sectional shapes of the posterior cruciate ligament were more circular near the tibia, becoming progressively more elongated toward the femur. The meniscofemoral ligaments were more circular than the cruciate ligaments, with an occasional medial-lateral widening similar to that of the posterior cruciate ligament. The cross-sectional area of both the cruciate ligaments changed along the length of the midsubstance, with the anterior cruciate ligament becoming slightly larger distally and the posterior cruciate ligament enlarging proximally. The angle of flexion of the knee was not found to have a significant effect on the cross-sectional areas of the ligaments but was noted to alter the cross-sectional shapes.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1996

Effect of tibial attachment location on the healing of the anterior cruciate ligament freeze model.

We studied the healing response of a devitalized anterior cruciate ligament to a treatment of initial anterior-posterior joint translation in goats. Devitalization and devascularization were achieved by five successive freeze-thaw cycles. Anterior-posterior translation was surgically altered by an osteotomy of the tibial attachment of the devitalized ligament and its reattachment either in the anatomical position or in a position 5 mm posterior. Six weeks after the first surgery, the same procedure was performed on the contralateral limb, except that the ligament was reattached in the alternate position. Six months after the initial surgery, femur-anterior cruciate ligament-tibia specimens were tested to determine their structural and mechanical material properties. Anatomic ligament placement resulted in reduced anterior-posterior translation (p < 0.05) and greater anterior joint stiffness (p < 0.05). Maximum load (p < 0.05) and ligament stiffness (p < 0.01) also were greater for the anatomically placed anterior cruciate ligaments. The maximum load for anatomically placed ligaments averaged 1.625 +/- 211 N (SEM). The strength of the posteriorly placed anterior cruciate ligament, 895 +/- 164 N was similar to results of historical anterior cruciate autograft reconstructions. Ligament failure occurred near the tibial insertion in the posteriorly placed ligaments more often than in the anatomically placed ligaments (four of five times compared with one of five times). Ligament failure near the tibial insertion occurred with lower mean maximum load than failure at the midsubstance or by bone avulsion (796 compared with 1.592 N: p < 0.05). These data support the hypothesis that ligament laxity is important to the healing and remodeling of anterior cruciate ligament grafts.

Animals↗
PubMedDate not supplied

Incidence and location of bone bruises after acute posterior cruciate ligament injury.

BACKGROUND: In patients suffering from an anterior cruciate ligament injury, the incidence and location of bone bruises are well documented. This study reports data regarding bone bruises after acute posterior cruciate ligament injury. HYPOTHESIS: Bone bruises associated with posterior cruciate ligament injury are common, and their location differs from those seen with anterior cruciate ligament injury. STUDY DESIGN: Retrospective cohort study. METHODS: Thirty-five consecutive patients were identified as having a grade II or III posterior cruciate ligament tear, with an intact anterior cruciate ligament, in which a magnetic resonance imaging scan had been obtained within 20 days of injury. Magnetic resonance imaging scans were reviewed to document bone bruises, associated medial or lateral ligamentous injury, and meniscal and chondral abnormalities. RESULTS: Of the 35 patients, 29 (83%) had a bone bruise in at least one location. Bone bruises were found throughout the joint, more widely dispersed than is commonly seen with anterior cruciate ligament injury. Also, 29 patients had magnetic resonance imaging findings of associated ligamentous injury. Lateral bone bruises were associated with medial collateral ligament injury, whereas medial bone bruises correlated with posterolateral injury. CONCLUSIONS: The incidence of bone bruises associated with posterior cruciate ligament injury is similar to that seen with anterior cruciate ligament injury. Their location is more widely dispersed. The location of a bone bruise should lead to careful magnetic resonance imaging inspection and physical examination for ligamentous injury to the opposite side of the joint. Truly isolated posterior cruciate ligament injuries are rare, as most occur with osseous and some degree of associated ligamentous injury.

Adolescent↗
PubMed1996

[Ultrasound imaging of the anterior cruciate ligament. Possibilities and limits].

We carried out sonography of the femoral origin of the anterior cruciate ligament in the dorsal cross section with a 7.5-MHz linear scanner in 25 test subjects with healthy knee joints. A physiological difference between the sides in the size of the hypoechoic region of the origin could be defined on the basis of the measurements obtained in both knee joints. Values outside a reference range which could be evaluated from this difference were rated as pathological in terms of an anterior cruciate ligament rupture. The reliability of this method in definitively diagnosing an anterior cruciate ligament rupture was analysed statistically as compared to the golden standard of arthroscopy on 65 patients by means of the two-by-two frequency table test. The femoral origin of the cruciate ligament in 25 test subjects had a median width of 3.1 mm (range 1.7-5.8 mm) on the right and 3.4 mm (range 1.7-4.4 mm) on the left. The median difference between the sides is 0.4 mm (range 0-1.8 mm). If the 3rd to the 97th percentile is selected as the reference range, our data show a physiological difference between the sides of 0-1.5 mm. The median age of the 65 patients was 31 years (range 14-74 years). Two thirds of all patients were men. A rupture of the anterior cruciate ligament was diagnosed sonographically in 19 patients. The result was confirmed arthroscopically in 15 patients. In 4 patients, there was a false positive sonographic finding. Forty-six patients did not fulfil the sonographic criteria of a rupture of the anterior cruciate ligament. Of these, 38 showed an intact anterior cruciate ligament on arthroscopy. Eight patients had a false-negative sonographic finding. The corresponding statistical analysis showed sensitivity of 65%, specificity of 90% and precision of 79%. Accordingly, the diagnostic reliability of knee joint sonography in diagnosing a rupture of the anterior cruciate ligament appears to be unsatisfactory, since old ruptures, above all, cannot be imaged with certainty (sensitivity 65%). On the other hand, a positive sonographic finding points with relative certainty to a rupture of the anterior cruciate ligament even before the operation (precision 79%). Histological analysis of the cruciate ligament preparations obtained intraoperatively showed that in particular the fresh anterior cruciate ligament rupture can be imaged sonographically. Retrospectively, knowledge of the history is thus crucial for interpretation of the sonographic image. After acute trauma to the knee, a side difference in the femoral region of origin of the anterior cruciate ligament of more than 1.5 mm, as revealed sonographically, is a certain indication that the anterior cruciate ligament is ruptured. When there is a positive sonographic finding, ligament strain, synovial bleeding and partial ruptures of the anterior cruciate ligament as well as plica ruptures must be considered as possible diagnoses.

Adolescent↗
PubMed1997

Changes in the flexibility characteristics of the ankle complex due to damage to the lateral collateral ligaments: an in vitro and in vivo study.

This study was part of a long-term effort to develop a reliable diagnostic procedure for ankle ligament injuries. Earlier efforts led to the development and validation of a six-degrees-of-freedom instrumented linkage capable of measuring the flexibility characteristics of the ankle complex in vitro and in vivo. The major goal of the present study was to determine if these flexibility measurements are sufficiently sensitive to detect the presence of damage to the lateral collateral ligaments of the ankle joint both in vitro and in vivo. The in vitro testing was conducted on the legs from six fresh cadavers before and after serial sectioning of the anterior talofibular ligament and the calcaneofibular ligament. The flexibility in inversion-eversion, anterior drawer, and internal-external rotation was measured before and after resection of the ligaments. The in vivo testing was conducted on five patients with unilateral injuries to the ankle ligament. The flexibility evaluation used for in vitro specimens was also performed on both the injured and the intact ankles. For the in vitro testing, the data analysis was based on comparison of flexibility values before and after resection of the ligaments, whereas the data analysis for the in vivo testing was based on comparison of the flexibility of the injured joint with that of the intact contralateral joint. The results of the in vitro study indicated that both an isolated rupture of the anterior talofibular ligament and combined damage of the anterior talofibular and calcaneofibular ligaments produce statistically significant changes in flexibility. Furthermore, the most sensitive parameters to the presence of ligament injuries were found to be early flexibility in anterior drawer, early flexibility in inversion, and the amount of coupling between internal rotation and inversion. These parameters provided a basis for differentiating between an isolated injury to the anterior talofibular ligament and a combined anterior talofibular and calcaneofibular ligament injury. For an isolated anterior talofibular ligament injury, a significant increase in flexibility in anterior drawer was present, whereas the increase in inversion flexibility or in the amount of coupling was insignificant. However, the increases in inversion flexibility and the amount of coupling became significant when both ligaments were involved. The results of the in vivo study indicated that significant changes in flexibility can be detected in patients with lateral ankle injuries. Finally, both the in vitro and in vivo results suggest that development of a reliable diagnostic test for ankle ligament injury based on changes in passive flexibility may be possible.

Adult↗
PubMed1987

[The ligament system of the spleen and its significance for surgical interventions].

The anatomy of the splenic ligaments was examined in twenty cadavars. Histologic sections were taken from ten. In one of these twenty cases the entire ligamentous structure was studied by serial sections using a polarizing light microscope. There are four principal ligaments of the spleen: the gastrosplenic ligament, the colicosplenic ligament, the phrenocolic ligament and the phrenosplenic (splenorenal) ligament. There are two portions to the gastrosplenic ligament. In the upper portion where the spleen is very close to the stomach, the collagen fibers appear more dense. The term splenorenal ligament is vague. This is because there are three structures between the spleen and the kidney besides the peritoneal layer: collagenous tissue with fat (pararenal fat), the prerenal fascia and a fat capsule (perirenal fat). The vascular anatomy is of interest. Running through the gastrosplenic ligament are small branches from the short gastric and left gastroomental vessels. The colicosplenic ligament receives little branches from the left gastroomentalic vessels and the lower pole vessels. The other ligaments have mainly venous vascularisation which can develop into a collateral network within splenomegaly. The direction of the collagen fibers in the splenic ligaments is important. In all the ligaments most of the fibers come from two directions: laterocranial to mediocaudal and mediocranial to laterocaudal. Splenic capsular tears are a recognized complication of upper abdominal surgery. This is because traction in the mediocaudal direction during gastric and colon surgery and in the mediocranial direction during gastric surgery is oriented in the same direction as the collagen fibers in the splenic ligaments and thus tears the splenic capsule.

Collagen↗
PubMedDate not supplied

[Mechanical resistance of pelvic ligaments used for incontinence or prolapse surgery].

OBJECTIVE: Underline the objective strength of the pelvic ligaments. PATIENTS AND METHODS: Twenty nine human female pelvis cadavers, whose storage conditions differed, were used in our study. In each cadaver we dissected all the ligaments used in pelvic surgery. A subjective clinical evaluation of the ligament properties was performed by visual observation as well as by finger palpation. Ligaments were classified into three groups in terms of thickness and apparent strength following finger palpation, high, doubtful and low apparent quality ligaments. Then a suture taking the entire ligament switched the ligaments and a force was applied on the vagina axis until tearing. The device used for strength measurement during traction was a Samson type force gauge, which was developed for the purpose of our study. Results were given in Newtons. RESULTS: We found a great variability in the values obtained at tearing with maximal values at 200 newtons and minimal at 22. Individually measured, ligament strength varied between individuals, and for a same patient between the type of ligaments and the side. The pre-vertebral ligament was on average the strongest. For bilateral ligaments, there was no difference between the left and right side. The iliopectineal ligament was statistically significantly stronger than sacrospinous and arcus tendineus of pelvic fascia. There was a correlation between subjective evaluation and objective strength measurements. DISCUSSION AND CONCLUSION: We performed the only study of the strength of pelvic ligaments at tearing. These are, however, routinely used in the cure of prolapse and urinary incontinence. Our results show that there is a great variability in strength between individuals, and for a same patient between the types of ligaments and side. These observations could explain some of the surgical intervention failures and demonstrate the importance of per-operative strength evaluation. Per-operative subjective evaluation on strength is related to objective measurements and could be used to determine the type of ligaments to be used for surgical assembly suspension.

Biomechanical Phenomena↗
PubMed2001

The anatomy of the ligaments of the wrist and distal radioulnar joints.

The ligaments of the wrist are responsible for guiding and constraining the complex motion of the carpal bones relative to the forearm bones, the metacarpals, and contiguous carpal bones. The majority of wrist ligaments are found within the joint capsule as organized thickenings composed of parallel collagen fascicles, small caliber nerves and blood vessels, and lined on their deep surfaces by synoviocytes. The palmar radiocarpal ligament complex is composed of the radioscaphocapitate, long radiolunate, radioscapholunate and short radiolunate ligaments. The ulnocarpal ligaments include the ulnolunate, ulnotriquetral and ulnocapitate ligaments. Dorsally, the radiocarpal joint is spanned by the dorsal radiocarpal ligament. Palmar ligaments connecting the proximal and distal carpal rows include the scaphotrapeziotrapezoid, scaphocapitate, triquetrocapitate and triquetrohamate ligaments. Within each row are interosseous ligaments connecting adjacent carpal bones, each divisible into dorsal and palmar components. There are unique regions within some of the ligaments, such as a zone of fibrocartilage in the proximal regions of the scapholunate and lunotriquetral interosseous ligaments, and strong deep regions connecting the trapezoid, capitate, and hamate. The distal radioulnar joint is connected by the triangular fibrocartilage complex, composed of a fibrocartilaginous disc and the palmar and dorsal radioulnar ligaments. The ulnocarpal ligaments attach to the palmar radioulnar ligament rather than directly to the ulna, allowing increased independence between wrist and forearm motion.

Forearm↗
PubMedDate not supplied

Ligaments of the ankle: normal anatomy with MR arthrography.

PURPOSE: Our purpose was to define the normal MR arthrographic anatomy of ankle ligaments. METHOD: Prior to injection of intraarticular gadolinium in cadaveric ankle joints, proton density and T2-weighted images were obtained to assess the integrity of the ligaments and tendons as well as the amount of preexisting joint effusion. Following injection of 10 ml of contrast agent (gadopentetate dimeglumine 1:250, Omnipaqe 300, Knox gelatin 50%, and methylene blue), T1-weighted images with fat saturation in axial, oblique axial, coronal, and sagittal planes were obtained in neutral, dorsiflexion, and plantar flexion positions. Specimens were sectioned, allowing anatomic and MR correlation. RESULTS: Contrast agent outlining anterior and posterior aspects of the anterior talofibular ligament and posterior talofibular ligament (PTAF) was a normal finding, related to anterior and posterior recesses of the ankle joint that extend out beyond these ligaments in an anteroposterior direction above the level of the ligaments. Intraarticular contrast material allowed resolution of superficial and deep components of the posterior tibiofibular ligament. Both were seen separately from PTAF with dorsiflexion. Posterior intermalleolar ligament was not present in our specimens. Visualization of calcaneofibular ligament was much improved by contrast material outlining the articular aspect of the ligament. Visualization of the syndesmotic ligamentous complex also was improved by contrast material outlining the articular side of the ligaments and separating them from adjacent bone. Superiorly, the distribution of contrast agent was limited by the interosseous ligament. Visualization of the medial collateral ligaments was not improved by the presence of the intraarticular contrast material. CONCLUSION: MR arthrography of the ankle allows improved visualization and evaluation of the lateral and syndesmotic ligamentous complex.

Ankle Joint↗
PubMed2007

Failure properties of cervical spinal ligaments under fast strain rate deformations.

STUDY DESIGN: The failure responses of the anterior longitudinal ligament, posterior longitudinal ligament, and ligamentum flavum were examined in vitro under large strain-rate mechanical loading. OBJECTIVE: To quantify the failure properties for 3 cervical spinal ligaments at strain rates associated with traumatic events. SUMMARY OF BACKGROUND DATA: There exists little experimentation literature for fast-rate loading of the cervical spine ligaments. The small amount of available information is framed only in extensive experimental coordinates, and not in the context of strains. METHODS: Bone-ligament-bone complexes were strained at fast rates, in an incrementally increasing loading protocol using a servohydraulic mechanical test frame. Failure loads and displacements were converted to engineering and true stress and strain values, and compared for the different ligaments (anterior longitudinal ligament, posterior longitudinal ligament, and ligamentum flavum), spinal levels (C3-C4, C5-C6, and C7-T1), and for male versus female specimens. RESULTS: There were no significant differences in force or true stress for gender or spinal level. There was a significant difference in force and true stress for ligament type. A difference was found between the posterior longitudinal ligament and ligamentum flavum for failure force, and between the ligamentum flavum and both the anterior and posterior longitudinal ligaments for failure true stress. No significant differences were found in true strain for ligament, gender, or spinal level. The mean ligament failure true strain was 0.81. Failure true strains were approximately 57% of the failure engineering strains. CONCLUSIONS: Once the injury mechanisms of the cervical spine are fully understood, computational models can be employed to understand the potentially traumatic effects of clinical procedures, and mitigate injury in impact, falls, and other high-rate scenarios. The soft tissue failure properties in this study can be used to develop failure tolerances in fast-rate loading scenarios. Failure properties of the anterior and posterior longitudinal ligaments were similar, and the same properties can be used to model both ligaments.

Aged↗
PubMed2006

Association between extrinsic and intrinsic carpal ligament injuries at MR arthrography and carpal instability at radiography: initial observations.

PURPOSE: To retrospectively compare the presence or absence of carpal instability on radiographs with the findings of magnetic resonance (MR) arthrographic evaluation of intrinsic and extrinsic ligament tears in patients with chronic wrist pain. MATERIALS AND METHODS: The institutional review board approved this study and did not require informed consent. Signs of carpal instability were assessed on static and dynamic radiographs of the wrist obtained in 72 patients (24 female, 48 male; mean age, 36 years; age range, 14-59 years) with posttraumatic wrist pain. MR arthrography was subsequently performed. Two musculoskeletal radiologists independently analyzed the radiographs and MR images. Each intrinsic and extrinsic ligament was individually evaluated for the presence of a ligament tear. The extent of the tear also was recorded. Interobserver agreement regarding MR arthrographic findings was tested by calculating kappa statistics. Statistical comparison between radiography and MR arthrography was performed by using the Fisher exact test. RESULTS: Twenty-five triangular fibrocartilage complex, 18 (five partial, 13 complete) scapholunate ligament, and 25 (10 partial, 15 complete) lunotriquetral ligament tears were visualized. Twenty-two (all complete) extrinsic ligament tears were detected: two radial collateral ligament, 10 radioscaphocapitate ligament, and 10 radiolunotriquetral ligament tears. Interobserver agreement regarding intrinsic and extrinsic ligament tear detection at MR arthrography was excellent (kappa = 0.80). Nineteen patients had evidence of carpal instability on radiographs. Fourteen (52%) of 27 patients with at least one complete intrinsic lesion had no sign of carpal instability. On the other hand, the association of scapholunate ligament and/or lunotriquetral ligament and extrinsic ligament tears was significantly correlated (P < .001) with carpal instability at radiography. CONCLUSION: The presence or absence of carpal instability on radiographs depends on the association between intrinsic and extrinsic ligament tears-even partial ones-rather than on the presence of intrinsic ligament tears alone, even when the tears are complete.

Adolescent↗
PubMedDate not supplied

Strain measurement in lateral ankle ligaments.

We measured strain in the lateral ligaments of 10 human cadaver ankles while moving the ankle joint and applying stress in a variety of ways. We studied the anterior talofibular, calcaneofibular, posterior talofibular, anterior tibiofibular, and posterior tibiofibular ligaments. Strain measurements in the ligaments were recorded continuously while the ankle was moved from dorsiflexion into plantar flexion. We then repeated measurements while applying inversion, eversion, internal rotation, and external rotation forces. Strain in the anterior talofibular ligament increased when the ankle was moved into greater degrees of plantar flexion, internal rotation, and inversion. Strain in the calcaneofibular ligament increased as the talus was dorsiflexed and inverted. These findings support the concept that the anterior talofibular and calcaneofibular ligaments function together at all positions of ankle flexion to provide lateral ankle stability. We measured maximum strain in the posterior talofibular ligament when the ankle was dorsiflexed and externally rotated. The strain in the anterior and posterior tibiofibular ligaments increased when the ankle was dorsiflexed. External rotation increased strain in the anterior tibiofibular ligament and decreased strain in the posterior tibiofibular ligament. Based upon strain measurements in the lateral ankle ligaments in various ankle joint positions, we believe the anterior talofibular ligament is most likely to tear if the ankle is inverted in plantar flexion and internally rotated. Theoretically, the calcaneofibular ligament tears primarily in inversion if the ankle is dorsiflexed; the anterior tibiofibular ligament tears in dorsiflexion, especially if combined with external rotation; and the posterior tibiofibular ligament tears with extreme dorsiflexion.

Adult↗