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The stabilizing role of the lateral ligament complex around the ankle and subtalar joints.

The stabilizing role of various ligaments in the lateral side of the ankle and hindfoot was examined experimentally and sequentially using 10 fresh amputated lower limbs. The anterior talofibular ligament contributed to ankle stability in plantarflexion and the calcaneofibular, the fibulotalocalcaneal, and posterior talofibular ligament in all positions. The lateral root of the inferior extensor retinaculum contributed to subtalar stability in neutral and dorsiflexion. The calcaneofibular, fibulotalocalcaneal, and cervical ligaments and the ligament of the anterior capsule of the posterior talocalcaneal joint and the interosseous ligaments contributed to subtalar stability in all positions. The subtalar joint accounted for upward of 50% of ankle/hindfoot inversion after ligament division in the intermalleolar plane.

Aged↗
PubMed1995

Deltoid ligament forces after tibialis posterior tendon rupture: effects of triple arthrodesis and calcaneal displacement osteotomies.

Deltoid ligament forces were studied after observing deltoid ligament insufficiency in several post-triple arthrodesis patients. Six fresh-frozen, below-knee amputation specimens were axially loaded. The results demonstrate that a properly positioned triple arthrodesis produced deltoid ligament forces that were similar to those seen with an intact tibialis posterior tendon. A triple arthrodesis in combination with a lateral displacement calcaneal osteotomy produced deltoid ligament forces that were 76% greater than those seen with the intact tibialis posterior tendon (P < .05). A triple arthrodesis in combination with a medial displacement calcaneal osteotomy produced deltoid ligament forces that were 56% less than those seen with the lateral displacement calcaneal osteotomy (P < .01). Patients with longstanding ruptures of the tibialis posterior tendon and associated peritalar subluxation/dislocation may have less than optimal clinical results after triple arthrodesis, unless the hindfoot can be properly reduced, due to persistent elevated forces in the deltoid ligament and resulting ligament laxity. This study suggests that a medial displacement calcaneal osteotomy in combination with a triple arthrodesis may be a viable treatment when the hindfoot cannot be positioned properly.

Ankle Joint↗
PubMed1977

Effect of hormones on collagen metabolism and collagenase activity in the pubic symphysis ligament of the guinea pig.

The ligament which forms between the pubic bones of the pregnant guinea pig offers a unique system for the study of hormonal regulation of connective tissue metabolism. During the 5 days prior to parturition the length and hydroxyproline content of the pubic symphysis increase threefold. In nonpregnant animals, ligament growth can be induced in an estrogen-primed animal only following the administration of the hormone relaxin. A further increase in length can be achieved when progesterone is also injected. Removal and culture of post-partum ligaments, which undergo a 75% reduction in length and hydroxyproline content by the fifth post-partum day, allowed the demonstration of high collagenase levels released into the media. In contrast, when ligaments from pre-partum period were cultured, low levels of collagenase were detected in the media. The rapid post-partum ligament resorption could be partially inhibited if estrogen was injected immediately following parturition, whereas progesterone or relaxin significantly impaired ligament resorption. In a corresponding fashion, when the collagenase levels of these ligaments were measured progesterone treatment was shown to inhibit collagenase activity markedly while estrogen was less effective. Relaxin however, appeared to have no direct inhibitory effect.

Animals↗
PubMed1992

A model of human knee ligaments in the sagittal plane. Part 1: Response to passive flexion.

The development of a mathematical model of the knee ligaments in the sagittal plane is presented. Essential features of the model are (a) the representation of selected cruciate ligament fibres as isometric links in a kinematic mechanism that controls passive knee flexion and (b) the mapping of all other ligament fibres between attachments on the tibia and femur. Fibres slacken and tighten as the ligament attachment areas on the bones move relative to each other. The model is used to study the shape and fibre length changes of the cruciate and collateral ligaments in response to passive flexion/extension of the knee. The model ligament shape and fibre length changes compare well qualitatively with experimental results reported in the literature. The results suggest that when designing and implanting a ligament replacement with the aim of reproducing the natural fibre strain patterns, the surgeon must not only implant through the natural attachment areas but must also maintain the natural fibre mapping and render all fibres just tight at the appropriate flexion angle.

Algorithms↗
PubMed1992

[A histological study of the augmented reconstruction of the anterior cruciate ligament in rabbits].

An experimental study was carried out to investigate the histological properties of the anterior cruciate ligament (ACL) reconstructed by the augmentation procedure. After the resection of 42 knees in 42 adult New Zealand white rabbits, 21 of the knees were reconstructed with a patellar tendon alone (nonaugmented group) and 21 with an augmented patellar tendon using a Leeds-Keio artificial ligament (augmented group). The rabbits were destroyed 4, 8, 12, 16 and 24 weeks, respectively, after the operation. After 4 weeks, a remarkable proliferation of fibrous tissue was present in the augmented group ligaments, while tissue necrosis was dominant, with slight granulation, in the nonaugmented group. After 8 weeks, the fibrous tissue was regularly arranged in a longitudinal direction in the augmented group, while this took 12 weeks in the nonaugmented group. Furthermore, 16 weeks postoperatively, the collagen fibers had matured and resembled normal ligaments in the augmented group, but this took 24 weeks in the nonaugmented group. After 16 weeks, columnar formations and some mineralization of the fibrocartilage were observed in the bone-ligament junctions in the nonaugmented group, but not until after 24 weeks in the augmented group. After 24 weeks, there were no histological differences between the two groups, either in the reconstructed ligaments or in the bone-ligament junctions. It is suggested that augmentation had an effect on the early histological maturation of collagen fibers, and an adverse effect on the formation of enthesis.

Animals↗
PubMed2002

Meniscofemoral ligaments revisited. Anatomical study, age correlation and clinical implications.

The meniscofemoral ligaments were studied in 84 fresh-frozen knees from 49 cadavers. Combined anterior and posterior approaches were used to identify the ligaments. In total, 78 specimens (93%) contained at least one meniscofemoral ligament. The anterior meniscofemoral ligament (aMFL) was present in 62 specimens (74%), and the posterior meniscofemoral ligament (pMFL) in 58 (69%). The 42 specimens (50%) in which both ligaments were present were from a significantly younger population than that with one MFL or none (p < 0.05). Several anatomical variations were identified, including oblique fibres of the posterior cruciate ligament (PCL), which were seen in 16 specimens (19%). These were termed the 'false pMFL'. The high incidence of MFLs and their anatomical variations should be borne in mind during arthroscopic and radiological examination of the PCL. It is important to recognise the oblique fibres of the PCL on MRI in order to avoid wrongly identifying them as either a pMFL or a tear of the lateral meniscus. The increased incidence of MFLs in younger donors suggests that they degenerate with age.

Adolescent↗
PubMed2004

Age-dependent decreases of sulfur and magnesium in human round ligaments of the uterus and relationships among elements.

To elucidate the compositional change of ligaments with aging, the authors investigated both age-related changes of elements and relationships among elements in the round ligaments of the uterus (round ligaments) by inductively coupled plasma-atomic emission spectrometry. The bilateral round ligaments were resected from 20 cadavers and also from the uteri removed surgically from 11 patients bearing uterine myoma or cancer. Thirty-one subjects ranged in age from 34 to 92 yr. It was found that both S and Mg decreased gradually in the round ligaments with aging, but Ca, P, Zn, Fe, and Al did not change significantly with aging. Regarding the relationships among elements, very significant direct correlations were found among the contents of Ca, P, S, and Mg in the round ligaments, whereas significant inverse correlations were found between the contents of Zn and elements, such as Ca, P, S, and Mg. It should be noted that there was an extremely significant direct correlation between Ca and P contents in the round ligaments.

Adult↗
PubMed2004

Age-related changes of elements and relationships among elements in human tendons and ligaments.

To elucidate compositional changes of the tendons and ligaments with aging, the authors investigated age-related changes of element contents in the insertion tendons of the biceps brachii muscle, central tendons of the diaphragma, Achilles' tendons, posterior longitudinal ligaments (PLLs) of the cervical spine, ligamenta capitum femorum, and anterior cruciate ligaments. After ordinary dissections by medical students, the three tendons and three ligaments were resected and element contents were determined by inductively coupled plasma-atomic emission spectrometry. It was found that the elements, such as Ca, P, S, Mg, Na, Zn, and Fe, did not change significantly in the three tendons and two ligaments with aging, except for the PLLs where Ca and Mg increased significantly with aging and Fe decreased significantly with aging. With regard to the relationships among elements, the common finding that there were significant correlations between Ca and P contents and between Ca and Mg contents was obtained in the three ligaments. Likewise, the common finding that there was a significant correlation between Ca and Mg contents was obtained in the three tendons. Regarding the relationship between Ca and P contents, the three tendons were different from the three ligaments.

Age Factors↗
PubMed1992

Histochemical and immunohistochemical demonstration of macrophages and dendritic cells in the lingual periodontal ligament of rat incisors.

The distribution of macrophages in the lingual periodontal ligament of rat incisors was surveyed by histochemical and immunohistochemical methods. Numerous macrophages showing intense ACPase reactions were located primarily in the shear zone of the periodontal ligament. Immunostaining with an ED1-monoclonal antibody that recognizes various subpopulations of macrophages revealed plentiful positive cells showing flamelike profiles throughout the periodontal ligament, in addition to regular macrophages associated with sinusoidal blood vessels. A similar distribution of flamelike cells expressing Ia antigens was demonstrable with immunostaining using an OX6-monoclonal antibody. A consecutive staining of sections for ACPase histochemistry followed by immunoreactions for Ia antigens revealed the presence of two types of the flamelike cells in the periodontal ligament: one with and the other without distinct ACPase activity, corresponding to the macrophage and the dendritic cell, respectively. Either type of flamelike cells was located in the bone-related and shear zones, whereas only dendritic cells without ACPase activity were restricted to the tooth-related zone. OX6-immunonegative cells showing ACPase reactions were also found in the periphery of the sinusoidal blood vessels. Our data are the first to demonstrate the abundance of macrophages and dendritic cells expressing Ia antigens throughout the lingual periodontal ligament of rat incisors. In addition to regular macrophages, an exclusive localization of macrophages with flamelike extensions has been demonstrated in the bone-related and shear zones of the ligament. The region-specific arrangement of macrophages and dendritic cells with various histochemical and immunological features suggests that the periodontal ligament of rat incisor is a useful model for analyzing the process of differentiation of antigen-presenting cells.

Acid Phosphatase↗
PubMed1983

The accuracy of double-contrast arthrographic evaluation of the anterior cruciate ligament. A retrospective review of one hundred and sixty-three knees with surgical confirmation.

In a retrospective review of 163 knees, the double-contrast arthrogram proved to be an accurate method of evaluating the anterior cruciate ligament. The status of the ligament was examined arthrographically with two stress lateral projections: a horizontal cross-table radiograph and a fluoroscopic spot radiograph. The condition of the ligament was interpreted as being normal, lax but intact, torn with intact synovial tissue, or torn or absent. The status of the ligament was subsequently determined at either arthrotomy or arthroscopy by inspection, palpation, and judgment of the degree of tension under stress. The arthrographic diagnosis was found to be 91.4 per cent accurate within the individual subclassifications and 95 per cent accurate in confirming the ligament to be either intact or abnormal. Injury to the anterior cruciate ligament frequently occurs in association with meniscal tears. In our series, 138 of the 163 knees had either a meniscal or a cruciate lesion, or both. Of these, forty-one (30 per cent) had a meniscal lesion, thirty-four (25 per cent) had a cruciate lesion, and sixty-three (45 per cent) had both. We have found the double-contrast arthrogram to be an accurate method of determining the condition of both the anterior cruciate ligament and the menisci in a single outpatient examination.

Adolescent↗
PubMed1999

Hamstring tendon grafts for reconstruction of the anterior cruciate ligament: biomechanical evaluation of the use of multiple strands and tensioning techniques.

BACKGROUND: Our hypothesis that multiple, equally tensioned strands of hamstring graft used for reconstruction of the anterior cruciate ligament are stronger and stiffer than ten-millimeter patellar ligament grafts was tested biomechanically with use of tendons from cadavera. METHODS: In the first part of the study, we measured the strength and stiffness of one, two, and four-strand hamstring grafts, from fresh-frozen cadaveric knees, that had been tensioned equally when clamped. In the second part of the study, we compared four-strand grafts to which tension had been applied by hand and then clamped with similar grafts to which tension had been applied with weights and then clamped. The grafts for the two experiments were obtained from thirty-four paired and ten unpaired knees. We also studied the effects of cooling on the biomechanical properties of grafts by comparing patellar ligament grafts tested at 13 degrees Celsius with those tested at room temperature. RESULTS: Two equally tensioned gracilis strands had 185 percent of the strength and 210 percent of the stiffness (1550+/-428 newtons and 336+/-141 newtons per millimeter, respectively) of one gracilis strand (837+/- 138 newtons and 160+/-44 newtons per millimeter, respectively). Two equally tensioned semitendinosus strands had 220 percent of the strength and 220 percent of the stiffness (2330+/-452 newtons and 469+/-185 newtons per millimeter, respectively) of one semitendinosus strand (1060+/-227 newtons and 213+/-44 newtons per millimeter, respectively). Four combined strands (two gracilis strands and two semitendinosus strands) that were equally tensioned with weights and clamped had the additive tensile properties of the individual strands. With the numbers available, four combined strands that were manually tensioned and clamped were not found to be significantly stronger or stiffer than two semitendinosus strands that were equally tensioned with weights (p>0.07). CONCLUSIONS: Four combined strands that were equally tensioned with weights and clamped were stronger and stiffer than all ten-millimeter patellar ligament grafts that have been described in previous reports. All strands of a hamstring graft must be equally tensioned for the composite to have its optimum biomechanical properties. CLINICAL RELEVANCE: Because of the well recognized donor-site morbidity associated with the use of patellar ligament grafts for reconstruction of the anterior cruciate ligament, multiple-strand hamstring-tendon grafts have become an increasingly popular choice. Our data demonstrate that equally tensioned four-strand hamstring-tendon grafts have initial tensile properties that are higher than those reported for ten-millimeter patellar-ligament grafts; thus, from a biomechanical point of view, they seem to be a reasonable alternative.

Aged↗
PubMed2002

Biomechanical comparison of tibial inlay and tibial tunnel techniques for reconstruction of the posterior cruciate ligament. Analysis of graft forces.

BACKGROUND: The tibial inlay technique of reconstruction of the posterior cruciate ligament offers potential advantages over the conventional transtibial tunnel technique, particularly with regard to the graft force levels that develop over a functional range of knee flexion. Abnormally high graft forces generated during rehabilitation activities could lead to stretch-out of the graft during the critical early healing period. The purpose of this study was to compare graft forces between these two techniques and with forces in the native posterior cruciate ligament. METHODS: A load cell was installed at the femoral origin of the posterior cruciate ligament in twelve fresh-frozen cadaveric knees to measure resultant forces in the ligament during a series of knee loading tests. The posterior cruciate ligament was then excised, and the femoral ends of 10-mm-wide bone-patellar tendon-bone grafts were attached to the load cell to measure resultant forces in the grafts. For the tunnel reconstruction, the distal bone block of the graft was placed into a tibial tunnel and thin stainless-steel cables interwoven into the bone block were gripped in a split clamp attached to the anterior tibial cortex. With the inlay technique, the distal bone block was fixed in a tibial trough with use of a cortical bone screw with a washer and nut. The proximal ends of all grafts were pretensioned to a level of force that restored intact knee laxity at 90 degrees of flexion, and loading tests were repeated. RESULTS: There were no significant differences in mean graft forces between the two techniques under tibial loads consisting of 100 N of posterior tibial force, 5 N-m of varus and valgus moment, and 5 N-m of internal and external tibial torque. Mean graft forces with the tibial tunnel technique were approximately 10 to 20 N higher than those with the inlay technique with passive knee flexion beyond 95 degrees. Mean graft forces with both reconstruction techniques were significantly higher than forces in the native posterior cruciate ligament with the knee flexed beyond approximately 90 degrees for all but one mode of loading. CONCLUSIONS: In this cadaveric testing model, neither technique for reconstruction of the posterior cruciate ligament had a substantial advantage over the other with respect to generation of graft forces.

Aged↗
PubMed2006

Arthroscopic treatment of partial scapholunate ligament tears in children with chronic wrist pain.

BACKGROUND: Scapholunate ligament injury is rare in the adolescent and pediatric population, and the results of treatment have not been well described. The purpose of the present study was to review the outcomes of arthroscopic management of patients with persistent wrist pain and scapholunate ligament injury as documented on arthroscopic examination who had had a failure of at least six months of nonoperative management. METHODS: The medical records of thirty-two pediatric and adolescent patients who underwent arthroscopic treatment of scapholunate ligament injuries were retrospectively reviewed to obtain preoperative and postoperative modified Mayo wrist scores, radiographic data, and intraoperative findings, including the classifications of interosseous ligament injury, chondral injury, and other abnormalities. Patients were contacted after a minimum of two years of follow-up for reevaluation of the Mayo wrist scores. RESULTS: Arthroscopic evaluation revealed thirty Geissler type-II tears and two Geissler type-III tears. In addition to these scapholunate ligament injuries, seven of the thirty-two patients had partial tears of the short radiolunate ligament that appeared to be at the site of impaction from carpal subluxation, twelve had a triangular fibrocartilage complex injury, and twenty-seven had a chondral injury. The modified Mayo wrist scores showed improvement following arthroscopic débridement of partial-thickness tears and associated chondral injuries. The average wrist score was 66.3 preoperatively and 91.6 at an average of forty-three months of follow-up. Eight patients required subsequent surgery because of deterioration in their clinical status. After a mean duration of follow-up of 30.8 months, the average wrist score was 87.1. CONCLUSIONS: The majority of pediatric and adolescent patients with wrist pain who have a failure of nonoperative management and who have a Geissler type-II scapholunate ligament tear on arthroscopic examination can have substantial long-term improvement following arthroscopic débridement of the tear combined with treatment of other associated injuries.

Adolescent↗
PubMed2006

Biomechanical studies of double-bundle posterior cruciate ligament reconstructions.

BACKGROUND: Double-bundle reconstruction of the posterior cruciate ligament has been advocated to better replicate the anatomy of the native ligament and restore normal knee biomechanics. The goal of this study was to measure knee laxities and graft forces following single and double-bundle reconstructions and to compare these values with those for the intact knee in a cadaver model. METHODS: Forces in the posterior cruciate ligament were measured as the knee was passively extended from 120 degrees to 0 degrees with applied tibial loading. Anterior-posterior laxities were measured as well. An anterolateral tunnel was located at the anterolateral margin of the native ligament footprint, and a posteromedial tunnel was placed at one of two locations within the footprint; one location resulted in a wide bridge separating the tunnels and the other, a narrow bridge. Testing was repeated with a single anterolateral graft tensioned to match, within +/-1 mm, the laxity in the intact knee at 90 degrees of flexion. Double-bundle reconstructions were tested with the addition of a posteromedial graft tensioned at 30 degrees of flexion. Two levels of posteromedial graft tension (10 and 30 N) were studied in both the narrow and the wide-bridge posteromedial tunnels. RESULTS: Mean laxities with a single anterolateral graft were 1.1 to 2.0 mm greater than normal between 0 degrees and 30 degrees of flexion. With the posteromedial graft tensioned to 10 N in the wide-bridge tunnel, the mean laxity of the double grafts was not significantly different from that in the intact knee at any flexion angle. With the posteromedial graft tensioned to 10 N in the narrow-bridge tunnel, the mean laxity at 0 degrees was 0.9 mm greater than that in the intact knee. With the posteromedial graft tensioned to 30 N, the mean laxity at 10 degrees was 1.7 mm less than the intact-knee value in the wide-bridge tunnel and 1.3 mm less than the intact-knee value in the narrow bridge-tunnel. Increasing posteromedial graft tension from 10 to 30 N decreased the mean laxities by 0.5 to 1.1 mm between 0 degrees and 30 degrees . Mean graft forces following a single anterolateral reconstruction were not significantly different from the native posterior cruciate ligament forces under any mode of loading except valgus moment. With the wide-bridge tunnel, the mean forces with the posteromedial graft tensioned to 10 N were somewhat higher than the native posterior cruciate ligament forces at full extension; when the graft was tensioned to 30 N, the mean forces were substantially higher. CONCLUSIONS: A single anterolateral graft best reproduced the normal posterior cruciate ligament force profiles, but laxities were greater than normal between 0 degrees and 30 degrees of knee flexion. The addition of a second, posteromedial graft reduced laxity in this flexion range but did so at the expense of higher-than-normal forces in the posteromedial graft.

Adult↗
PubMed1991

MR imaging of the lateral collateral ligament of the ankle.

The ankle is stabilized by three sets of ligaments: the medial collateral (deltoid) ligament, the syndesmotic ligamentous complex, and the lateral collateral ligament. Of these three, the lateral collateral ligament is the one most often injured in ankle sprains. Assessment of the extent of injury has classically relied on clinical evaluation; plain film radiographs (including stress views); and, in some acute situations, ankle arthrography and/or peroneal tenography. In this report we illustrate the use of MR in the evaluation of the lateral collateral ligament. The normal anatomy, pitfalls in image interpretation, and findings in cases of ligamentous injury are demonstrated.

Ankle Joint↗
PubMed1994

Meniscal tears missed on MR imaging: relationship to meniscal tear patterns and anterior cruciate ligament tears.

OBJECTIVE: MR imaging of the knee is a valuable technique for diagnosing meniscal tears, but some tears found at arthroscopy are not shown on MR imaging. The purpose of this study was to determine whether or not tears were more frequently missed in the presence of an anterior cruciate ligament tear or when tears had certain locations or configurations. MATERIALS AND METHODS: We reviewed the original MR reports and surgical records of 400 patients who had both an MR examination and arthroscopy of the knee. Using chi 2 analysis, we examined how the sensitivity for detecting meniscal tears varied with the presence of a tear of the anterior cruciate ligament, with the location of the tear within the meniscus, and among six configurations of meniscal tears. We also studied whether sensitivity decreased with an increasing delay between MR examination and arthroscopy. RESULTS: In the presence of a tear of the anterior cruciate ligament, the sensitivity decreased from 0.97 to 0.88 (p = .016) for medial meniscal tears and from 0.94 to 0.69 (p = .0005) for lateral tears. The overall sensitivity for lateral meniscal tears was significantly less for posterior (p = .001) and peripheral (p = .005) tears than for other tear locations or configurations. The sensitivities did not significantly differ between tear locations and configurations in the medial meniscus or with an increasing delay until arthroscopy. Patients with a torn anterior cruciate ligament were more likely to have peripheral tears of the medial meniscus (p = .00004) and posterior (p = .0004) and peripheral (p = .04) tears of the lateral meniscus. CONCLUSION: Because of their location and configuration, meniscal tears associated with an anterior cruciate ligament injury are more difficult to detect on MR images than are tears in knees with an intact ligament. If a tear of the anterior cruciate ligament is detected, special attention should be given to the subtle peripheral tears that may be present in either meniscus, but most commonly in the posterior horn of the lateral meniscus. These tears are especially difficult to detect on MR images.

Adult↗
PubMed2005

MRI of spring ligament tears.

OBJECTIVE: Surgical repair of the spring ligament is becoming recognized as an important management component of adult-acquired flatfoot, yet little literature exists on the MRI appearance of spring ligament abnormalities. In this article, we describe the MRI appearance of surgically proven spring ligament tears. CONCLUSION: MRI findings present in surgically proven spring ligament tears include an abnormal spring ligament caliber, signal intensity, waviness, a full-thickness gap, and posterior tibial tendonopathy. The finding unique to cases with surgically proven tears is a full-thickness gap in the ligament, seen in 79% of the cases in our series. When multiple abnormalities are seen in the spring ligament in conjunction with a full-thickness gap, the diagnosis of a tear can be made with confidence.

Adult↗
PubMed2006

Inclination of the patellar ligament in relation to flexion angle in stifle joints of dogs without degenerative joint disease.

OBJECTIVE: To measure the angles between the patellar ligament and the tibial plateau and between the patellar ligament and the common tangent at the tibiofemoral contact point (TFCP) throughout the full range of motion of the stifle joint in dogs and determine the flexion angles at which the patellar ligament is perpendicular to the tibial plateau or to the common tangent. SAMPLE POPULATION: 16 hind limbs from cadavers of 9 adult dogs without radiographically detectable degenerative joint disease. PROCEDURES: Mediolateral radiographic views of the stifle joints from full extension through full flexion were obtained (10 degrees increments). Angles between the tibial and femoral long axes (beta), between the patellar ligament and the tibial plateau gamma), and between the patellar ligament and the common tangent at TFCP (alpha) were measured. Data were analyzed via simple linear regression. RESULTS: In canine stifle joints, angles gamma and alpha decreased linearly with increasing flexion (angle beta). The patellar ligament was perpendicular to the tibial plateau and perpendicular to the common tangent at the TFCP at 90 degrees and 110 degrees of flexion, respectively. CONCLUSIONS AND CLINICAL RELEVANCE: By use of the conventionally defined tibial plateau, data suggest that at approximately 90 degrees of flexion in stifle joints of dogs, shear force in the sagittal plane exerted on the proximal portion of the tibia shifts the loading from the cranial to the caudal cruciate ligament. Analyses involving the common tangent at the TFCP (a more anatomically representative reference point) identified this crossover point at approximately 110 degrees of joint flexion.

Animals↗