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PubMed2004

The effect of anterior cruciate ligament reconstruction on the risk of knee reinjury.

BACKGROUND: Although there is evidence that very active, young patients are better served with anterior cruciate ligament reconstruction, there is a lack of objective data demonstrating that future knee injury is prevented by these procedures. HYPOTHESIS: Anterior cruciate ligament reconstruction protects against reinjury of the knee that would require reoperation. STUDY DESIGN: Retrospective cohort study. METHODS: A cohort of 6576 active-duty army personnel who had been hospitalized for anterior cruciate ligament injury from 1990 to 1996 were identified. Using the Total Army Injury and Health Outcomes Database, the authors followed these individuals for up to 9 years and collected clinical, demographic, and occupational data. These data were evaluated with bivariate and multivariable analyses to determine the effect of anterior cruciate ligament reconstruction on the rate of knee reinjury that required operation. RESULTS: Of the 6576 study subjects, 3795 subjects (58%) underwent anterior cruciate ligament reconstruction and 2781 (42%) did not. The rate of reoperation was significantly lower among the anterior cruciate ligament reconstruction group (4.90/100 person-years) compared with those treated conservatively (13.86/100 person-years; P < .0001). Proportional hazard regression analyses adjusted for age, race, sex, marital status, education, and physical activity level confirmed that anterior cruciate ligament reconstruction was protective against meniscal and cartilage reinjury (P < .0001). Secondary medial meniscal injury was more common than secondary lateral meniscal injury (P < .003). Younger age was the strongest predictor of failure of conservative management leading to late anterior cruciate ligament reconstruction (P < .0001). CONCLUSIONS: Anterior cruciate ligament reconstruction protected against reoperation in this young, active population; younger subjects were more likely to require late anterior cruciate ligament reconstruction. CLINICAL RELEVANCE: Strong consideration should be given to anterior cruciate ligament reconstruction after anterior cruciate ligament injury in young, active individuals.

Adult↗
PubMedDate not supplied

The influence of muscle forces and external loads on cruciate ligament strain.

We know it is important to avoid excessive strain on reconstructed ligaments, but we do not know how individual muscles affect cruciate ligament strain. To answer this, we studied the effect of muscle forces and external loads on cruciate ligament strain. Nine cadaveric knee joints were tested in an apparatus that allowed unconstrained knee joint motion. Quadriceps, hamstring, and gastrocnemius muscle forces were simulated. Additionally, external loads were applied such as varus-internal or valgus-external rotation forces. Cruciate ligament strain was recorded at different knee flexion angles. Activation of the gastrocnemius muscle significantly (P < 0.05) strained the posterior cruciate ligament at flexion angles larger than 40 degrees. Quadriceps muscle activation significantly strained the anterior cruciate ligament when the knee was flexed 20 degrees to 60 degrees (P < 0.01) and reduced the strain on the posterior cruciate ligament in the same flexion range (P < 0.05). Activation of the hamstring muscles strained the posterior cruciate ligament when the knee was flexed 70 degrees to 110 degrees (P < 0.05). Combined varus and internal rotation forces significantly increased anterior cruciate ligament strain throughout the flexion range (P < 0.05). The results suggest that to minimize strain on the ligament after posterior cruciate ligament surgery, strong gastrocnemius muscle contractions should be avoided beyond 30 degrees of knee flexion. The study also calls into question the use of vigorous quadriceps exercises in the range of 20 degrees to 60 degrees of knee flexion after anterior cruciate ligament reconstruction.

Adult↗
PubMed1999

[Synovial healing in reconstructed cruciate ligaments. Our personal experience compared in single interventions and combined reconstructions].

INTRODUCTION: The healing process of tendon grafts used in cruciate ligament reconstruction is called ligamentization. The tendon structural architecture changes progressively into the histological appearance of normal ligament. Amiel and Clancy have demonstrated that this process is time-dependent in anterior cruciate ligament (ACL) reconstruction, the tendon graft taking one year to become similar to a normal cruciate ligament. Three different maturation phases of anterior cruciate graft ligamentization can be seen at MRI: periligamentous proliferation, intraligamentous proliferation and definitive healing. We report our MR findings in the reconstruction of single ACL, posterior cruciate ligament (PCL), and of both ACL and PCL. MATERIAL AND METHODS: January 1995 to January 1999 we selected 60 patients submitted to arthroscopic cruciate ligament reconstruction. The ACL was reconstructed with the patellar tendon in 22 cases and the PCL in 23; fifteen patients underwent double reconstruction of ACL, with hamstring tendons, and PCL, with patellar tendons. Fifty-five patients were followed-up with MRI: 45 with a dedicated permanent magnet (Artroscan, Esaote Biomedica, Genoa, Italy) and 10 with a permanent low-field unit (AIRIS, Hitachi, Japan); the same technical parameters were used in all cases. Forty of 55 patients were examined at 1, 3, 6, 9 and 12 postoperative months, while 15 were followed-up longer (12 to 36 months postoperatively). At the first follow-up MR examination, 5 patients (2 ACL and 3 PCL) were excluded for incorrect tunnel position (1 case), hypertrophic scarring (2 cases) and new trauma (2 cases). MR findings were compared with clinical data of joint stability. RESULTS: MRI showed the different stages of the healing process in 20 ACL patients: proliferating soft tissue around the graft with the low signal intensity typical of tendons (stage I, 1-3 months postoperatively), the graft becomes progressively hyperintense (stage II, 3-9 months postoperatively), and finally the low signal intensity indicating completed ligamentization (stage III, 12 months postoperatively). As for PCL reconstructions, MR findings were similar but the process took longer, even 24 months. Finally, in the 15 cases of double reconstruction, both grafts were difficult to distinguish on T1-weighted images for a very long time (24-36 months postoperatively). DISCUSSION AND CONCLUSIONS: Relative to the ACL, ligamentization takes longer for PCL and combined ACL and PCL reconstructions, probably because the morphological changes in PCL and double grafts may be impaired by many factors, such as gravity, long bone tunnels, hemarthrosis, hyperplastic synovial reaction in the intercondylar notch; also, rehabilitation protocols differ in ACL from PCL patients. No signs of instability were found at physical or arthrometric examinations. MRI demonstrates the different stages of ligamentization and thus proves a useful tool for postoperative follow-up in cruciate ligament reconstructions. Contrast-enhanced (Gd) studies are reserved to the cases of graft impingement or if other abnormalities are suspected.

Anterior Cruciate Ligament↗
PubMed1991

[Biological response following alloplastic replacement of the anterior cruciate ligament with PET-ribbon (Trevira hochfest)].

A total of 97 cruciate ligament prostheses were implanted in 70 patients following acute and chronic cruciate ligament rupture; the average life of these prostheses being 3 years (8-53 months), 5 (5.15%) were removed due to failure after a mean of 9 (3-15) months. In 67 cases of chronic cruciate instability, 60 anterior and 7 posterior Trevira cruciate ligament prostheses were implanted, and 25 acute anterior and five acute posterior cruciate ligament ruptures were also treated with Trevira ligaments augmentations. The follow-up rate of patients with Trevira cruciate ligament repair was 97%. Of the explanted polyethylene-terephthalate (PET) devices, 4 had intra-articular ruptures at the bone tunnel entry and 1 had become unstable with no dislocation of staples. Investigation by scanning electron and light microscopy showed no bony ingrowth of the Trevira ligaments. Instead there was fibrous tissue ingrowth in all parts of the prostheses (intra-articular, bone tunnels and anchoring regions). The extent of foreign-body reaction at the Trevira ligament boundary differed with the intensity of mechanical strain at the three parts of the implants (intra-articular, bone tunnel, periosteum). Inflammatory cells and foreign-body giant cells were abundant close to the site of ligament rupture at the intra-articular entries of the bone tunnels. These cells were scarce at the intra-articular parts of the ligament prostheses and at the periosteal anchor points. Evaluation of the reasons for prosthetic ligament failure shows that (1) nonideal placement of bone tunnels and (2) inadequate strain during rehabilitation resulted in instability and rupture after anterior cruciate replacement with Trevira ligaments.

Adolescent↗
PubMed1995

The fibre bundle anatomy of human cruciate ligaments.

The cruciate ligaments of the knee consist of numerous fascicles, groups of which comprise fibre bundles. The stabilising function of these ligaments is established by changes in the lengths and orientations of the fascicles. Understanding the function of knee ligaments thus requires an understanding of their 3-dimensional fascicle architecture. Hitherto, the cruciate ligaments have been considered functionally as single-dimensional 'ropes' or, at the most, as consisting of anterior and posterior parts. It is evident from the appearance of these ligamentous structures, however, that fascicles in more than 2 directions are present. This study investigated how many and which fibre bundles are minimally needed to preserve the main fascicle directions in the ligaments. An anatomical analysis of the cruciate ligaments was performed using a 3-dimensional measuring device. Three anterior and 3 posterior cruciate ligaments were isolated and their fascicles measures. Based on the courses of the fascicles, fibre bundles were defined, dissected bluntly, and their corresponding insertion sites measured. Finally, the insertion sites of the bundles were connected into straight-line representations by a computer and transformed to the anatomical position of the knee, so as to be useful for functional analyses of the ligaments. It was found that 6-10 bundles are sufficient to represent the main fascicle directions of the ligaments. Although the number of fibre bundles is not identical for all ligaments, the femur and the tibia are connected in a consistent way by these bundles. Even the ways in which the fibre bundles change their interrelationship from the femoral to the tibial insertion sites are comparable. The results serve as a detailed anatomical basis for functional analyses of the cruciate ligaments.

Anterior Cruciate Ligament↗
PubMed1996

Human (and some other primates') uterine teres ligament represents a mammalian developmental novelty.

BACKGROUND: The primordia of the structures developing into the mammalian male cremaster sacs emerge as well in females fetuses. In most species the structures developing from these primordia in females remain inconspicuous: the so-called uterine teres ligament consisting of a slender part across the uterine broad ligament and a more or less developed bulbous structure at the site where this ligament inserts into the inguinal abdominal bottom. Not many data are available concerning the growth, development, or function of the uterine teres ligament. In humans--and also in other "higher" female primates--the uterine teres ligament is a major structure consisting mainly of smooth musculature. It is attached to the ventral aspect of the tubo-uterine junction. From there it courses across the uterine broad ligament and extends, retroperitoneally, to the inguinal region where it pierces through the inguinal canal to end in the tissues ventral of the pubic bones. OBSERVATIONS: Analysis of the fetal development of the human uterine teres ligament, as compared with that of various other non-primate mammals, offers an explanation for its unusual anatomical condition. Evidence is conferred that, in human fetuses, there is no counterpart for the slender ligament across the broad ligament in other mammals. Instead, the homologue of the rudimentary bulbous structure in the abdominal bottom of non-primate females develops into a strong muscular structure which is directly connected to the (para-)menonephric duct wall. CONCLUSION: It is concluded that the human uterine teres ligament is to be judged a structure different from that of other, non-primate, mammals. It is speculated that the unusual structure of the human teres ligament is related to one or more of the many unusual features of human uterine development: as a single organ (uterus simplex), with a position deep in the abdominal cavity below the pelvic brim, and far away from the posterior abdominal wall. The unusual anatomical position may require an unusual construction of the uterine suspensory apparatus of which the teres ligament is one component.

Adult↗
PubMed1984

Ligamentous structures of the metacarpophalangeal joint: a quantitative anatomic study.

The ligamentous structure of the metacarpophalangeal (MCP) joint of the index finger in human cadavers was studied by gross examination and quantitative measurement. Anatomically, the collateral ligament is separable into two layers, with the precise origin arising from the metacarpal head and inserting on the proximal phalanx. Quantitatively, the change in length of the collateral ligament was studied with biplanar radiographic techniques. The distance between the origin and insertion of the collateral ligament changed in different portions of the ligament when the joint was moved from a position of hyperextension to that of flexion. When the MCP joint was flexed from 0 degree to 80 degrees, the dorsal portions of both the radial and ulnar collateral ligaments were lengthened (3-4 mm). The middle portions of both ligaments were slightly elongated (0.4-1.0 mm), and the volar portions of the ligaments were shortened (1-2 mm). When the MCP joint extended into hyperextension, the dorsal portions of the ligaments shortened 2-3 mm, the middle thirds of the ligaments shortened slightly, and the volar thirds of the ligaments lengthened. The results of this study suggest that the dorsal and volar portions of the collateral ligament provide MCP joint constraint at the flexed and extended positions, respectively.

Biomechanical Phenomena↗
PubMed1997

Effect of growth factors on matrix synthesis by ligament fibroblasts.

Although it has been reported that several growth factors modulate soft-tissue healing, the specific effects of growth factors on protein synthesis during ligament healing have not been widely investigated. In this study, we examined the effects of basic and acidic fibroblast growth factors, transforming growth factor beta 1, and epidermal growth factor on collagen and noncollagenous protein synthesis by cultured fibroblasts from medial collateral ligament and anterior cruciate ligament in vitro. Uptake of tritiated proline was used to measure synthesis of collagen and noncollagenous protein, and sodium dodecyl sulfate-polyacrylamide gel electrophoresis was used to analyze the type of collagens synthesized. Our data showed that transforming growth factor beta 1 increased both collagen and noncollagenous protein synthesis by medial collateral and anterior cruciate ligament fibroblasts on a dose-dependent basis. Collagen synthesis by cultured fibroblasts from the medial collateral and anterior cruciate ligaments was increased by treatment with transforming growth factor beta 1 by as much as approximately 1.5 times that of untreated controls. Although the response to transforming growth factor beta 1 by anterior cruciate ligament fibroblasts was equal to that by medial collateral ligament fibroblasts, the amounts of matrix proteins synthesized by anterior cruciate ligament fibroblasts were approximately half of that by medial collateral ligament fibroblasts. The increase was mostly in type-I collagen. Treatment of anterior cruciate ligament fibroblasts with epidermal growth factor increased collagen synthesis by approximately 25% but had little effect on medial collateral ligament fibroblasts. Neither basic nor acidic fibroblast growth factor increased either collagen or noncollagenous protein synthesis. These findings suggest that topical application of transforming growth factor beta 1, alone or in combination with epidermal growth factor, may have the potential to strengthen the ligament by increasing matrix synthesis during its remodeling and healing processes.

Analysis of Variance↗
PubMed1997

In situ forces in the anterior cruciate ligament and its bundles in response to anterior tibial loads.

The anterior cruciate ligament has a complex fiber anatomy and is not considered to be a uniform structure. Current anterior cruciate ligament reconstructions succeed in stabilizing the knee, but they neither fully restore normal knee kinematics nor reproduce normal ligament function. To improve the outcome of the reconstruction, it may be necessary to reproduce the complex function of the intact anterior cruciate ligament in the replacement graft. We examined the in situ forces in nine human anterior cruciate ligaments as well as the force distribution between the anteromedial and posterolateral bundles of the ligament in response to applied anterior tibial loads ranging from 22 to 110 N at knee flexion angles of 0-90 degrees. The analysis was performed using a robotic manipulator in conjunction with a universal force-moment sensor. The in situ forces were determined with no device attached to the ligament, while the knee was permitted to move freely in response to the applied loads. We found that the in situ forces in the anterior cruciate ligament ranged from 12.8 +/- 7.3 N under 22 N of anterior tibial load applied at 90 degrees of knee flexion to 110.6 +/- 14.8 N under 110 N of applied load at 15 degrees of flexion. The magnitude of the in situ force in the posterolateral bundle was larger than that in the anteromedial bundle at knee flexion angles between 0 and 45 degrees, reaching a maximum of 75.2 +/- 18.3 N at 15 degrees of knee flexion under an anterior tibial load of 110 N. The magnitude of the in situ force in the posterolateral bundle was significantly affected by knee flexion angle and anterior tibial load in a fashion remarkably similar to that seen in the anterior cruciate ligament. The magnitude of the in situ force in the anteromedial bundle, in contrast, remained relatively constant, not changing with flexion angle. Significant differences in the direction of the in situ force between the anteromedial bundle and the posterolateral bundle were found only at flexion angles of 0 and 60 degrees and only under applied anterior tibial loads greater than 66 N. We have demonstrated the nonuniformity of the anterior cruciate ligament under unconstrained anterior tibial loads. Our data further suggest that in order for the anterior cruciate ligament replacement graft to reproduce the in situ forces of the normal anterior cruciate ligament, reconstruction techniques should take into account the role of the posterolateral bundle in addition to that of the anteromedial bundle.

Adult↗
PubMed1997

Temporal and spatial expression of transforming growth factor-beta in the healing patellar ligament of the rat.

We investigated the temporal and spatial expression of transforming growth factor-beta in the healing patellar ligament of the rat by immunohistochemistry. The mid-portion of the medial half of the patellar ligament in 14-week-old male Wistar rats was cut transversely with a scalpel. On day 1 after ligament injury, diffuse staining for transforming growth factor-beta was observed in the extracellular matrix filling the wound, and the staining in the adjacent ligament tissue was as weak as it was in the normal ligament. On day 3, the intensity of the diffuse extracellular staining decreased, and the staining was observed in correspondence with the cellular distribution in the wound site and in the adjacent uninjured ligament tissue. On day 7, the intense staining was widely distributed over the whole length of the ligament tissue. On day 28, the staining for transforming growth factor-beta was still observed at the wound site and in the adjacent uninjured ligament tissue, where the staining was reduced in intensity but still stronger than it was in the normal ligament. On day 56, the expression of transforming growth factor-beta was still detectable at the wound site; however, in the adjacent uninjured ligament tissue, it had almost subsided to the normal level. The results of the present study suggest that ligament healing may be accompanied by extensive changes in the expression of transforming growth factor-beta over the whole length of ligament tissue.

Animals↗
PubMed2000

Importance of the medial meniscus in the anterior cruciate ligament-deficient knee.

The incidence of meniscal tears in the chronically anterior cruciate ligament-deficient knee is increased, particularly in the medial meniscus because it performs an important function in limiting knee motion. We evaluated the role of the medial meniscus in stabilizing the anterior cruciate ligament-deficient knee and hypothesized that the resultant force in the meniscus is significantly elevated in the anterior cruciate ligament-deficient knee. To test this hypothesis, we employed a robotic/universal force-moment sensor testing system to determine the increase in the resultant force in the human medial meniscus in response to an anterior tibial load following transection of the anterior cruciate ligament. We also measured changes in the kinematics of the knee in multiple degrees of freedom following medial meniscectomy in the anterior cruciate ligament-deficient knee. In response to a 134-N anterior tibial load, the resultant force in the medial meniscus of the anterior cruciate ligament-deficient knee increased significantly compared with that in the meniscus of the intact knee; it increased by a minimum of 10.1 N (52%) at full knee extension to a maximum of 50.2 N (197%) at 60 degrees of flexion. Medial meniscectomy in the anterior cruciate ligament-deficient knee also caused a significant increase in anterior tibial translation in response to the anterior tibial load, ranging from an increase of 2.2 mm at full knee extension to 5.8 mm at 60 degrees of flexion. Conversely, coupled internal tibial rotation in response to the load decreased significantly, ranging from a decrease of 2.5 degrees at 15 degrees of knee flexion to 4.7 degrees at 60 degrees of flexion. Our data confirm the hypothesis that the resultant force in the medial meniscus is significantly greater in the anterior cruciate ligament-deficient knee than in the intact knee when the knee is subjected to anterior tibial loads. This indicates that the demand on the medial meniscus in resisting anterior tibial loads is increased in the anterior cruciate ligament-deficient knee compared with in the intact knee, suggesting a mechanism for the increased incidence of medial meniscal tears observed in chronically anterior cruciate ligament-deficient patients. The large changes in kinematics due to medial meniscectomy in the anterior cruciate ligament-deficient knee confirm the important role of the medial meniscus in controlling knee stability. These findings suggest that the reduction of resultant force in the meniscus may be a further motive for reconstructing the anterior cruciate ligament, with the goal of preserving meniscal integrity.

Aged↗
PubMed2000

Pregnancy affects cellular activity, but not tissue mechanical properties, in the healing rabbit medial collateral ligament.

Recently, evidence has been accumulating that ligament and joint laxity is altered in women and rabbits during pregnancy. Furthermore, many female adolescents injure ligaments through participation in athletics and other activities. Therefore, to determine whether pregnancy has different effects on the injured and uninjured medial collateral ligament of the rabbit knee, we investigated cellular changes (mRNA levels) and alterations in tissue properties (biomechanics) accompanying pregnancy in animals with the medial collateral ligament injured during adolescence and bred for their primigravid pregnancy as young adults. Assessment of mRNA levels for matrix molecules, matrix metalloproteinases and tissue inhibitor of metalloproteinase-1, growth factors and sex hormone receptors, inflammatory cytokines, inducible nitric oxide synthase, and cyclooxygenase-2 by semiquantitative reverse transcription-polymerase chain reaction revealed that pregnancy had different impacts on scar and uninjured tissue for six of 15 genes assessed. A pregnancy-associated increase in laxity of the medial collateral ligament was observed for rabbits in the uninjured primigravida group; however, no increase was observed for injured rabbits during pregnancy. The injured ligament was already significantly more lax than the normal counterpart, and pregnancy did not lead to additional laxity or prevent the normal decline in laxity as the scar matured in nonpregnant animals. These results indicate that the impact of pregnancy on laxity and cell activity of the medial collateral ligament is dependent on whether the ligament is uninjured or injured. Pregnancy had no significant effect on structural (stiffness and failure load), material (stress at failure and Young's modulus), or viscoelastic (cyclic and static relaxation) properties of tissue from uninjured or injured medial collateral ligament. Therefore, the properties of the healing ligament were not adversely affected during pregnancy in this experimental model. However, it remains to be determined if these results with an injured medial collateral ligament can be extrapolated to the injured anterior cruciate ligament.

Animals↗
PubMed1999

The capsular ligaments of the wrist: morphology, morphometry and clinical applications.

Variable wrist ligament descriptions and nomenclatures have been presented, but the dimensions of these ligaments have not yet been extensively investigated. To verify the numerous concepts advanced and to provide a better understanding of individual variations in carpal biomechanics, and the numerous pathomechanical concepts reported in the literature, this study aimed to determine capsular carpal ligament anatomy, their dimensions and variations. The origin, insertion, and number of fascicles of the capsular wrist ligaments were observed in precise dissection of 66 anatomic preparations. The dimensions of several capsular wrist ligaments were measured using a calliper: the parameters analysed being length and width at three levels each, from which mean length and width and approximate mean surface (product of mean length by mean width) were determined. The anatomy of the capsular ligaments of the wrist showed, besides relatively constant structures, considerable individual variations, particularly of the ulnocarpal and dorsal ligaments. The standard deviations of ligament lengths and widths were mostly less than 20% of the average value. Some measurements, however, showed larger variations, such as those associated with the dorsal scaphotriquetral and ulnocarpal ligaments. Ligament widths generally showed larger variations and less interdependency than did ligament lengths. The capsular wrist ligaments display morphologic and morphometric variations, which could explain the biomechanical variations reported in the literature, and the diversity of classifications and treatment methods proposed for carpal instability. Further studies, however, are needed to confirm this hypothesis.

Anthropometry↗
PubMed1999

Functional anatomy of the lateral collateral ligament complex of the elbow.

Postero-lateral instability of the elbow joint is a rare clinical condition, commonly related to a disruption of the lateral collateral ligament complex of the elbow. Twenty elbow joint specimens were studied in order to describe the morphologic characteristics of this complex, and to determine the role of its different components in the stability of the elbow. After a morphologic and morphometric investigation, serial divisions of the medial bundle of the lateral collateral ligament were performed, with or without section of the annular ligament and the anterior bundle of the lateral collateral ligament. The anterior and medial bundles of the lateral collateral ligament had close relationships with the annular ligament and a common proximal course. Isolated section of the medial bundle of the lateral collateral ligament induced only minor laxity of the elbow joint. Combined divisions of the medial and the anterior bundles at their humeral insertion, or the medial bundle and the annular ligament at their ulnar insertion resulted in a reproducible subluxation of the ulno-humeral joint. Thus, postero-lateral rotatory stability of the elbow joint is largely maintained by the lateral collateral ligament complex, composed of three elements: the anterior and medial bundles of the lateral collateral ligament, and the annular ligament. In clinical practice, chronic postero-lateral instability is best treated by a ligamentous reconstruction, that must take into account all these anatomic considerations. We report here a new technique of ligamentoplasty using the fascia of the extensor carpi ulnaris muscle.

Aged↗
PubMed2002

MR imaging of the alar ligament: morphologic changes during axial rotation of the head in asymptomatic young adults.

OBJECTIVE: . The alar ligament plays a critical role in limiting the axial rotation of the head, the left alar ligament being stretched on rotation to the right and vice versa. The purposes of this study were to assess the usefulness of MR imaging in demonstrating the alar ligament and also to identify its morphologic changes during axial rotation of the head in asymptomatic young volunteers. DESIGN AND PATIENTS: . Twenty-two healthy volunteers participated in this study. All subjects underwent four series of contiguous fast spin echo density-weighted MR images with a 2 mm slice thickness including axial and coronal images with the head in neutral position, and coronal images with alternate head rotation to the right and left. The alar ligaments seen on each series of MR images were visually graded 0-2, and grade comparisons were performed between the four series of MR images. We also assessed the morphologic changes of the alar ligament on coronal images during axial rotation of the head. RESULTS: . Grade comparisons for the demonstration of the alar ligament revealed that each of three series of coronal images was statistically significantly better in grade than axial images. During axial rotation of the head, MR images showed rather constant morphologic changes of the alar ligament: elevation and wrapping of the contralateral alar ligament around the dens, associated with slightly upward movement of C1-C2 on that side. This wrap-around effect of the contralateral alar ligament in relation to the dens sometimes caused the apparent shortening of the alar ligament on that side. CONCLUSION: . Reliable assessment of the anatomy and function of the alar ligament can be achieved with MR imaging, preferably in coronal planes. MR imaging with the aid of a functional study may be a valuable imaging modality in the evaluation of alar ligament failure.

Adult↗
PubMed1999

Injuries of the lateral collateral ligaments of the ankle: assessment with MR imaging.

The aim of this study was to evaluate the ability of MRI to display injuries of the lateral collateral ligamentous complex in patients with an acute ankle distorsion trauma. The MR examinations of 36 patients with ankle pain after ankle distorsion were evaluated retrospectively without knowledge of clinical history, outcome and/or operative findings. The examinations were performed on a 1. 5-T whole-body imager using a flexible surface coil. The signs for ligamentous abnormality were as follows: complete or partial discontinuity, increased signal within, and irregularity and waviness of the ligament. The results were compared with operative findings in 18 patients with subsequent surgical repair. Eighteen patients with conservative therapy had a follow-up MR examination after 3 months. There was 1 sprain, 3 partial and 32 complete tears of the anterior talofibular ligament, and 5 sprains, 5 partial, and 7 complete tears of the calcaneofibular ligament. There were no lesions of the posterior talofibular ligament. Compared with surgery, MRI demonstrated in 18 of 18 cases the exact extent of anterior talofibular ligament injuries and underestimated the extent in 2 of 8 cases of calcaneofibular ligament injury. In patients with follow-up MRI after conservative therapy, a thickened band-like structure was found along the course of the injured ligament in 17 of 18 cases. The absence of ligament repair after conservative treatment was confirmed during operative revision in one case. The MRI technique allows for grading of the extent of injury of the lateral collateral ligamentous complex after acute ankle strain. It seems to be suitable for monitoring the healing process after conservative-functional treatment of ligament tears.

Acute Disease↗
PubMed2004

Does the fabella contribute to the reinforcement of the posterolateral corner of the knee by inducing the development of associated ligaments?

The fabellofibular (FF) and arcuate ligaments are closely colocated at the posterolateral corner of the knee. However, a bony fabella is often absent in Japanese subjects. We investigated these structures morphometrically using 212 knees. A thick FF ligament was found in 38.1% (40/105) of knees with a hard fabella. When identified histologically, a bony fabella accompanied a thick FF in 82.8% (24/29). Conversely, a thin or indefinite FF ligament and an elastic-textured fabella co-existed in 77.9% (60/70) of knees. There were no strong correlations between the morphology of the fabella and the arcuate ligament. Thus, a hard or bony fabella seemed to relate to thickening of the FF ligament. In contrast, the thicknesses of the FF and arcuate ligaments were negatively correlated. When the FF ligament was more than 5 mm thick, indicating that it was as strong as the lateral collateral ligament, no arcuate ligament could be identified. Conversely, a thin or indefinite FF ligament often accompanied a well-developed arcuate ligament (61.9%, 96/155). Our observations suggest that these ligaments act in a complementary manner to stabilize the posterolateral corner. A possible common function is fixation of the popliteal tendon on the joint capsule and lateral meniscus, rather than direct stabilization against rotation stress.

Aged↗
PubMed2005

Plasma estrone sulphate (E1S) and estradiol-17beta (E2beta) profiles during pregnancy and their relationship with the relaxation of sacrosciatic ligament, and prediction of calving time in Holstein-Friesian cattle.

The objectives of this study were to investigate the plasma E(1)S and E(2)beta profiles during pregnancy and their relationship with the relaxation of sacrosciatic ligament in Holstein-Friesian cattle (n=37) and then to predict the calving time on the basis of E(1)S and E(2)beta profiles and relaxation of the ligament. Blood samples were collected at 4 weeks intervals from days 100 to 190, at 2 weeks intervals from days 190 to 250, every week from days 250 to 270 and thereafter every day from day 270 of gestation until the day after calving. The relaxation in the ligament was measured by using two scales as a distance at a schedule similar to blood sampling plus 5 days postpartum. One scale was kept firm exactly parallel to the ligament between the sacrum and the tuber ischii and other scale was erected perpendicularly to the first scale with the bottom just touching the ligament and the depth was measured in the second scale from the point where it touched the ligament to the point where it touched the first scale. Plasma samples were analyzed for E(1)S and E(2)beta by enzyme immunoassay. E(1)S concentration was low at day 100 (0.8+/-0.3 ng/ml), then increased progressively and drastically to reach the level of 28.4+/-3.6 ng/ml on the day before calving and declined significantly (p<0.05) at 9.5+/-3.1 ng/ml within 1 day postpartum. There was a gradual increase in concentration of E(2)beta from day 100 of gestation (0.1+/-0 ng/ml) until day 4 prepartum (0.6+/-0 ng/ml). Thereafter, it increased drastically and reached the peak level of 1.0+/-0.1 ng/ml (p<0.05) on the day before calving and declined markedly at 0.4+/-0.1 ng/ml within 1 day postpartum (p<0.05). Corresponding to E(1)S and E(2)beta concentrations, a gradual increase in the relaxation of the ligament was observed from day 100 of gestation (8+/-1mm) until day 2 prepartum (24+/-2mm). Thereafter, it showed a significant increase (p<0.05) within 1 day before calving (31+/-2mm) and almost no difference between day 1 prepartum and day 1 postpartum. A marked decrease (p<0.05) was observed thereafter until day 3 postpartum (10+/-2mm) and no significant change between days 3 and 4 as well as 4 and 5 postpartum. The increment of E(2)beta by >or=0.20 ng/ml from the preceding day concentration was 85.2% accurate for predicting calving within 24h in many of the cows (23 of 37) in the herd. The increment in ligament relaxation measurement by >or=5mm from the preceding day measurement was the most efficacious to predict calving within 24h with the highest accuracy (93.9%) in high proportions of cows (31 of 37) in the herd. In conclusion, plasma E(1)S and E(2)beta concentrations and relaxation of sacrosciatic ligament increased gradually as gestation advanced and reached the peak level on the day before calving. The relaxation in the ligament corresponded well to plasma E(2)beta concentrations. Prediction of calving was possible by E(2)beta profile and relaxation in the ligament but not by E(1)S profile. The increment in ligament measurement by >or=5mm from the preceding day measurement was the most useful and accurate in predicting calving within 24h. It is economical and easily applicable in the field condition.

Animals↗