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At least 685 records · Page 38Linked to original sources
PubMed2004

Ligament fibre recruitment at the human ankle joint complex in passive flexion.

Knowledge of ligament fibre recruitment at the human ankle joint complex is a fundamental prerequisite for analysing mobility and stability. Previous experimental and modelling studies have shown that ankle motion must be guided by fibres within the calcaneofibular and tibiocalcaneal ligaments, which remain approximately isometric during passive flexion. The purpose of this study was to identify these fibres. Three below-knee amputated specimens were analysed during passive flexion with combined radiostereometry for bone pose estimation and 3D digitisation for ligament attachment area identification. A procedure based on singular value decomposition enabled matching bone pose with digitised data and therefore reconstructing position in space of ligament attachment areas in each joint position. Eleven ordered fibres, connecting corresponding points on origin and insertion curves, were modelled for each of the following ligaments: posterior talofibular, calcaneofibular, anterior talofibular, posterior tibiotalar, tibiocalcaneal, and anterior tibiotalar. The measured changes in length for the ligament fibres revealed patterns of tightening and slackening. The most anterior fibre of the calcaneofibular and the medio-anterior fibre of the tibiocalcaneal ligament exhibited the most isometric behaviour, as well as the most posterior fibre of the anterior talofibular ligament. Fibres within the calcaneofibular ligament remain parallel in the transverse plane, while those within the tibiocalcaneal ligament become almost parallel in joint neutral position. For both these ligaments, fibres maintain their relative inclination in the sagittal plane throughout the passive flexion range. The observed significant change in both shape and orientation of the ankle ligaments suggest that this knowledge is fundamental for future mechanical analysis of their response to external forces.

Ankle Joint↗
PubMed2001

Uterosacral ligament: description of anatomic relationships to optimize surgical safety.

OBJECTIVE: To determine the optimal site in the uterosacral ligament for suspension of the vaginal vault with regard to adjacent anatomy and suspension strength. METHODS: Fifteen female cadavers were evaluated between December 1998 and September 1999. Eleven hemisected pelves were dissected to better define the uterosacral ligament and identify adjacent anatomy. Ureteral pressure profiles with and without relaxing incisions were done on four fresh specimens. Suture pullout strengths also were assessed in the uterosacral ligament. RESULTS: The uterosacral ligament was attached broadly to the first, second, and third sacral vertebrae, and variably to the fourth sacral vertebrae. The intermediate portion of the uterosacral ligament had fewer vital, subjacent structures. The mean +/- standard deviation distance from ureter to uterosacral ligament was 0.9 +/- 0.4, 2.3 +/- 0.9, and 4.1 +/- 0.6 cm in the cervical, intermediate, and sacral portions of the uterosacral ligament, respectively. The distance from the ischial spine to the ureter was 4.9 +/- 2.0 cm. The ischial spine was consistently beneath the intermediate portion but variable in location beneath the breadth of the ligament. Uterosacral ligament tension was transmitted to the ureter, most notably near the cervix. The cervical and intermediate portions of the uterosacral ligament supported more than 17 kg of weight before failure. CONCLUSION: Our findings suggest that the optimal site for fixation is the intermediate portion of the uterosacral ligament, 1 cm posterior to its most anterior palpable margin, with the ligament on tension.

Broad Ligament↗
PubMed2000

The manual stress test may not be sufficient to differentiate ankle ligament injuries.

OBJECTIVE: To assess the accuracy of stress tests (anterior drawer, talar tilt) in the diagnosis of lateral ligament injuries.Design. Stress tests were performed in vitro, and rotation and displacement of the calcaneus relative to the tibia were measured. BACKGROUND: Stress tests are commonly used to diagnose ankle injuries. However, it is controversial as to whether stress tests can accurately differentiate between isolated anterior talofibular ligament injuries and combined anterior talofibular and calcaneofibular ligament injuries. METHODS: Stress tests were performed in vitro under three conditions with both ligaments intact, after sectioning the anterior talofibular ligament, and after sectioning the anterior talofibular and calcaneofibular ligament. Motion of the calcaneus relative to the tibia was measured in neutral and in 20 degrees of plantarflexion at the ankle. RESULTS: There were statistically significant differences among cadavers, examiners and positions. There was a difference between isolated anterior talofibular ligament sectioning and combined anterior talofibular and calcaneofibular ligament sectioning in lateral tilt but not in anterior displacement. In contrast, a difference was found between intact and anterior talofibular ligament sectioned specimens in anterior displacement but not in lateral tilt. However the differences were not great enough to differentiate between the two conditions. CONCLUSIONS: Each of the stress tests provides reasonable hindfoot displacement but neither is sufficient for accurate diagnosis of specific ligament involvement due to the large amount of individual variation. RELEVANCE: Many clinicians rely on stress tests to diagnose lateral ligament injuries and to assess the extent of anatomic disruption. This in vitro study has demonstrated poor correlation between clinical stress tests and the degree of ligamentous disruption.

Aged↗
PubMed2001

Injury initiation and progression in the anterior cruciate ligament.

OBJECTIVE: To develop a theoretical model to identify mechanisms by which total and partial tears of the anterior cruciate ligament could occur. DESIGN: A sagittal-plane knee model was used to investigate anterior cruciate ligament injury due to excessive anterior tibial translation. The ligament was modelled as an ordered array of fibres linking femur and tibia. BACKGROUND: Despite years of research, the detailed biomechanics of anterior cruciate ligament injury is not well understood. METHODS: A "critical strain criterion" was used to identify the onset and progression of model ligament fibre disruption. The associated forces were also calculated. RESULTS: At low flexion angles (<20 degrees ), the posterior fibre of the model ligament failed first, and the tear progressed anteriorly through the ligament. At higher flexion angles, the anterior fibre failed first, and the tear progressed posteriorly. Near the flexion angle at which the progression of injury changed direction, all fibres failed at approximately the same anterior tibial translation. At all but very high flexion angles, the force supported by the injured ligament was maximum when initial fibre failure occurred; the force then decreased with increasing anterior tibial translation. CONCLUSIONS: Near (20 degrees ) flexion, all model anterior cruciate ligament fibres fail at approximately the same anterior tibial translation, implying that a partial ligament tear may be impossible in this flexion region. Relevance. This study provides insight into possible mechanisms of initiation and progression of anterior cruciate ligament injury. It suggests that a partial tear of the posterior half of the ligament may be difficult to detect clinically.

Anterior Cruciate Ligament Injuries↗
PubMedDate not supplied

Tensile properties of the superior glenohumeral and coracohumeral ligaments.

Recent evidence has shown that the superior glenohumeral ligament (SGHL) and coracohumeral ligament (CHL) are important static stabilizers. To clarify the function of these two ligaments, we studied their tensile properties with bone-ligament-bone complexes from fresh-frozen shoulders, 10 SGHLs and 10 CHLs. Each ligament's cross-sectional area was measured, and uniaxial tensile testing of each complex was performed. The stiffness, ultimate load, percent elongation, and energy absorbed to failure of each bone-ligament-bone complex were derived from its load-elongation curve. The cross-sectional area of the coracohumeral ligament was significantly greater than that of the superior glenohumeral ligament of their midportions (CHL, 53.7 +/- 3.2 mm2 vs. SGHL, 11.3 +/- 1.6 mm2, p < 0.05). Results also reveal significant differences between the tensile properties for the two ligaments, with the coracohumeral ligament possessing greater stiffness (CHL, 36.7 +/- 5.9 N/mm vs. SGHL, 17.4 +/- 1.5 N/mm, p < 0.05) and ultimate load (CHL, 359.8 +/- 40.3 N vs. SGHL, 101.9 +/- 11.5 N, p < 0.05) than the superior glenohumeral ligament. Our findings confirm that the coracohumeral ligament is an important capsuloligamentous structure of the glenohumeral joint.

Adult↗
PubMed1999

Molecular biology and biomechanics of normal and healing ligaments--a review.

OBJECTIVE: In this review article, we discuss current data and concepts concerning the molecular biology and biomechanics of both normal and healing ligaments in a rabbit model. METHOD: Data is presented from light microscopy, transmission electron microscopy, molecular biology (RT-PCR), and biomechanical measurements (laxity, stress at failure, modulus, and static creep) or normal, pregnant and healing rabbit medial collateral ligaments. RESULTS: 'Flaws' in scar matrix, smaller-than-normal diameter collagen fibrils, and failure of collagen cross-link maturation may be particularly important deficiencies which appear to be related to ligament scar weakness and perhaps to scar creep. The mechanical behaviours of both normal and healing ligaments are altered by relative states of joint motion and normal ligaments are affected by systemic hormones (particularly during pregnancy). DISCUSSION: Molecular analysis of ligaments and ligament scars, combined with ongoing morphological and biomechanical studies of ligament structure and function, will ultimately reveal which factors can be manipulated clinically to optimize the restoration of normal ligament properties after ligament injuries. Further studies on the mechanisms of ligament healing, genetic markers of repair, and gender-specific differences in ligament repair responses are required.

Animals↗
PubMedDate not supplied

Ligamentous and tendinous anatomy of the intermetacarpal and common carpometacarpal joints: evaluation with MR imaging and MR arthrography.

PURPOSE: The purpose of this work was to demonstrate the normal ligamentous and tendinous anatomy of the intermetacarpal (IMC) and common carpometacarpal (CCMC) joints with MRI and MR arthrography. METHOD: MR images of 22 wrists derived from fresh human cadavers were obtained before and after arthrography. The MR imaging features of the ligaments and tendons about the CCMC and IMC joints and the joints themselves were analyzed in a randomized fashion and correlated with those seen on anatomic sections. RESULTS: Six CCMC ligaments were visualized. The dorsal and palmar CCMC ligaments and the pisometacarpal ligament were best visualized in the sagittal plane. The radial and ulnar CCMC collateral ligaments and the capito-third metacarpal ligament were best visualized in the coronal plane. Three main IMC ligaments were observed: a dorsal and a palmar ligament and an interosseous ligament complex. All three ligaments were best visualized in the axial plane. Four tendinous insertions to the metacarpal bases were evident. CONCLUSION: The anatomy of the ligaments and tendinous insertions about the second to fifth IMC and the CCMC joints is well demonstrated by MR imaging and MR arthrography. MR arthrography does not significantly improve the visualization of these complex structures.

Aged↗
PubMed2000

The iliolumbar ligament: three-dimensional volume imaging and computer reformatting by magnetic resonance: a technical note.

STUDY DESIGN: An assessment of magnetic resonance imaging techniques of the iliolumbar ligament. OBJECTIVES: To identify a technique to better image the iliolumbar ligament. SUMMARY OF BACKGROUND DATA: The iliolumbar ligament plays an important role in providing lumbosacral stability. Two-dimensional magnetic resonance imaging of the lumbar spine only provides a fragmented representation of the ligament. METHODS: A two-part study was performed. In the first part, three cadaver pelvi were dissected, and the individual bands of the iliolumbar ligament were identified. Computer reformatting of magnetic resonance three-dimensional volume images then were performed, correlating the structural characteristics of the iliolumbar ligament to its magnetic resonance image. In the second part of the study, the lumbosacral region of three groups of patients were evaluated. Group I was studied with routine magnetic resonance imaging techniques of the intervertebral disc regions. Group II was studied with routine contiguous axial magnetic resonance imaging of the lumbosacral spine. Group III was studied with computer reformatting of three-dimensional volume images of the lumbosacral spine. RESULTS: Accurate imaging of the iliolumbar ligament of cadaver specimens was achieved with three-dimensional volume imaging and computer reformatting. Routine imaging of the intervertebral disc region as well as contiguous axial imaging of the spine depicted only limited segments of the iliolumbar ligament. Three-dimensional volume imaging and computer reformatting allowed precise imaging of the iliolumbar ligament in all patients, demonstrating the ligament orientation as well as length, width, and depth. CONCLUSION: Only images of the iliolumbar ligament obtained through computer reformatting of three-dimensional volume averaging from L3 to the sacral ala correlated with the ligament's structural characteristics.

Adult↗
PubMed2001

Ossification of the posterior longitudinal ligament in vitamin D-resistant rickets: case report and review of the literature.

STUDY DESIGN: A case report of cervical myelopathy caused by ossification of the posterior longitudinal ligament in a patient with vitamin D-resistant rickets is presented together with a review of literature. OBJECTIVE: To report the diagnosis of ossification of the posterior longitudinal ligament in a white woman with vitamin D-resistant rickets. SUMMARY OF BACKGROUND DATA: The association between ossification of the posterior longitudinal ligament and untreated vitamin D-resistant rickets has been reported in Japan, but infrequently in white populations. In whites, ossification of the posterior longitudinal ligament is closely associated with diffuse idiopathic skeletal hyperostosis. A clear association between ossification of the posterior longitudinal ligament and vitamin D-resistant rickets in white populations has not yet been established. METHODS: The medical record and imaging studies of a patient treated at the authors' institution for cervical myelopathy caused by ossification of the posterior longitudinal ligament in the setting of treated vitamin D-resistant rickets were reviewed. A Medline search of the medical literature between 1966-1999 was performed to identify pertinent studies and similar case reports. RESULTS: The occurrence of spinal stenosis in untreated adults with vitamin D-resistant rickets has been reported in all regions of the spine in Japanese patients. The association between ossification of the posterior longitudinal ligament and untreated vitamin D-resistant rickets was first reported in Japan, where ossification of the posterior longitudinal ligament is endemic. This association may be incidental, because reports on ossification of the posterior longitudinal ligament in whites are not as frequent as in Japanese, reflecting the higher prevalence of this condition in Japan. CONCLUSION: Ossification of the posterior longitudinal ligament and ossification of the posterior longitudinal ligament associated with deranged calcium or phosphate metabolism may be different pathologic entities sharing a common outcome. Adequate treatment of vitamin D-resistant rickets may not always prevent or reverse ossification of the posterior longitudinal ligament.

Bone Density↗
PubMed2004

Biomechanical role of lumbar spine ligaments in flexion and extension: determination using a parallel linkage robot and a porcine model.

STUDY DESIGN: Porcine lumbar spine specimens were cyclically loaded in flexion and extension with a pure moment. The resistance to flexion and extension of the individual spinal elements was quantified using a sequential resection procedure. OBJECTIVE: To determine the biomechanical contribution of the individual posterior spinal ligaments, including the interconnections between the supraspinous and interspinous ligaments, to resisting flexion-extension moments applied to the lumbar spine. SUMMARY OF BACKGROUND DATA: Numerous experimental studies have performed repeated tests with sequential resection to determine the role of spinal ligaments. Most studies have not maintained the kinematics across trials, and therefore these studies have assessed the kinematics and kinetics of injured spines rather than delineating the mechanics of individual ligaments. METHODS: The L4-L5 motion pathway for pure moment loading (between in 16 Nm of flexion and 12 Nm of extension) of porcine spinal specimens was learned and replayed using a parallel-linkage robot. Each specimen was tested 6 times, with sequential resections performed as follows: intact, cut interconnections between the supraspinous and interspinous ligaments, supraspinous ligament removed, interspinous ligament removed, ligamentum flavum cut, and facet joints removed. The kinematic pathway was repeated for each of these tests, and, accordingly, the changes in loads between trials reflected the mechanics of the cut/removed structures. RESULTS: The interaction between the supraspinous and interspinous ligaments is a significant contributor to the flexion resistance of the porcine lumbar spine, resisting 10.5% of the peak flexion moment. This contribution is similar to the interspinous ligament (11.3%) and almost as large as the supraspinous ligament (14%) and facet joints (14.2%). The supraspinous/interspinous ligament complex was the largest contributor to the resistance of flexion motion (35.9%), followed by the intervertebral disc (25.2%) and the ligamentum flavum (24.7%). The only structures involved in resisting extension were the facet joint complexes, intervertebral disc, and possibly the spinous processes. CONCLUSIONS: The supraspinous/interspinous ligament complex is the largest contributor to resisting applied flexion moments in the porcine lumbar spine.

Animals↗
PubMed2002

Anatomic variations of the coracoacromial ligament in neonatal cadavers: a neonatal cadaver study.

One of the most common causes of pain and disability in the upper limb is inflammation of the rotator cuff tendons. When no significant bony abnormality exists in the surrounding structures, the coracoacromial ligament has been implicated as a possible cause of impingement on the cuff tendons and various morphological variants of the ligament have so far been claimed to be either the cause or the result of impingement. In this study, 110 shoulders from 60 neonatal cadavers that were preserved in a preparation of formaldehyde were dissected. Anatomic variations of coracoacromial ligaments were investigated with metric and histologic analysis. Three main ligament types were identified: quadrangular, broad band and U-shaped. The multiple banded ligament was not found. Histologic analysis showed that in U-shaped ligaments a thin tissue existed in the central part of the ligament close to the coracoid. Comparing our data with the adult measurements of a previous study we suggest that the primordial ligament is broad shaped, but assumes a quadrangular shape due to the different growth rates of the coracoid and acromial ends. We also suggest that broad and U-shaped ligaments account for the primordial and quadrangular and Y-shaped ligaments account for the adult types of the single or double banded anatomic variants respectively. Our results show that various types of the coracoacromial ligament are present at the neonatal period and that the final shape of the ligament should be defined by developmental factors, rather than degenerative changes.

Acromioclavicular Joint↗
PubMed2004

The anterior dural (Hofmann) ligaments.

STUDY DESIGN: A dissection-based study of 18 embalmed cadavers (7 male, 11 female), mean age 84 (+/-8.4) years. OBJECTIVE: To determine the morphology and morphometry of the anterior dural (Hofmann) ligaments. SUMMARY OF BACKGROUND DATA: The attachment of the posterior longitudinal ligament to the dura mater is poorly understood. Anterior dural ligaments connect the anterior dura to the deep layer of the posterior longitudinal ligament, but appear to be limited to the lumbar region and have been observed to have a craniocaudal orientation. Their function is reported to help in supporting and protecting the dural sac and spinal cord. METHODS: The spinal canal was opened exposing the dural sac, the spinal nerve roots incised, and spinal cord removed to mobilize the dural sac and gain access to Hofmann ligaments. The extent, orientation, length, and level of origin and insertion of the ligaments were documented. RESULTS: The orientation of the ligaments changed from caudocranial (dura to posterior longitudinal ligament) at upper thoracic levels to transverse at the level of T8-T9 to craniocaudal at lower thoracic and lumbar levels, often with multiple ligaments being present at a single level. Ligament length varied from 0.5 to 28.8 mm and was positively correlated with vertebral level and negatively correlated with orientation. CONCLUSIONS: Hofmann ligaments are present at most levels between C7 and L5; although most ligaments were limited to a single vertebral segment, some were observed to cross several segments.

Aged↗
PubMed1990

The effect of damage to the lateral collateral ligaments on the mechanical characteristics of the ankle joint--an in-vitro study.

Injuries to the lateral collateral ligaments of the ankle joint are among the most frequently occurring injuries at the lower limb. The present study was conducted for the purpose of establishing the basis for the development of a quantitative diagnostic procedure for such injuries. To achieve this goal, the effect of four types of ligament injuries on the three-dimensional mechanical characteristics of the ankle were investigated. These types of injuries consisted of: 1) isolated tear of the anterior talofibular ligament; 2) isolated tear of the calcaneofibular ligament; 3) isolated tear of the posterior talofibular ligament; and 4) combined tear of both the anterior talofibular ligament and the calcaneofibular ligament. The experiments were conducted on 31 amputated lower limbs and consisted of comparing the three-dimensional load-displacement and flexibility characteristics of the ankle joint prior to and following sectioning of selected ligaments. The experimental and analytical procedures used to derive these characteristics was developed previously by the authors. From the results of this study it was concluded that the three-dimensional flexibility characteristics of the ankle joint are strongly influenced by damage to the lateral collateral ligaments. Furthermore, it was found that each type of ligament injury produced unique and identifiably changes in the flexibility characteristics of the ankle. These unique changes, which are described in detail in this paper, can be used to discriminate between the different types of ligament injuries. Consequently, it was concluded that it is feasible to develop a quantitative diagnostic procedure for ankle ligament injuries based on the effect of the injury on the flexibility characteristics of the ankle.

Aged↗
PubMed2003

Extrinsic carpal ligaments: normal MR arthrographic appearance in cadavers.

PURPOSE: To describe the normal magnetic resonance (MR) arthrographic anatomy of the major carpal ligaments (excluding scapholunate and lunotriquetral ligaments) and their osseous attachments by using standard imaging planes. MATERIALS AND METHODS: MR images of 22 wrists derived from fresh human cadaveric hands were obtained after tricompartmental arthrography. The MR arthrographic appearance of the carpal ligaments and their bone attachments were analyzed and correlated to those seen on anatomic sections. Two readers determined in consensus which was the best plane to observe the course and attachment sites for each ligament. They further analyzed the size and sites of attachment of these ligaments in two orthogonal planes chosen for optimal viewing. RESULTS: Each ligament was well seen as a hypointense linear structure with MR arthrography. The radioscaphocapitate, radiolunotriquetral, radioscapholunate, dorsal radiotriquetral, palmar scaphotriquetral, and dorsal scaphotriquetral ligaments were best evaluated in the transverse plane. The palmar and dorsal ulnotriquetral and ulnolunate ligaments were best visualized in the sagittal plane. The radial collateral ligament was best analyzed in the coronal plane. The attachment sites of all ligaments were best analyzed either in the transverse or sagittal planes. CONCLUSION: MR arthrography allows visualization of the carpal ligaments. Detailed knowledge of the normal appearance of these ligaments can serve as a baseline for future studies in which MR arthrography is used to characterize wrist instability.

Aged↗
PubMedDate not supplied

Ligamentous restraints to external rotation of the humerus in the late-cocking phase of throwing. A cadaveric biomechanical investigation.

The late-cocking phase of throwing is characterized by extreme external rotation of the abducted arm; repeated stress in this position is a potential source of glenohumeral joint laxity. To determine the ligamentous restraints for external rotation in this position, 20 cadaver shoulders (mean age, 65 +/- 16 years) were dissected, leaving the rotator cuff tendons, coracoacromial ligament, glenohumeral capsule and ligaments, and coracohumeral ligament intact. The combined superior and middle glenohumeral ligaments, anterior band of the inferior glenohumeral ligament, and the entire inferior glenohumeral ligament were marked with sutures during arthroscopy. Specimens were mounted in a testing apparatus to simulate the late-cocking position. Forces of 22 N were applied to each of the rotator cuff tendons. An external rotation torque (0.06 N x m/sec to a peak of 3.4 N x m) was applied to the humerus of each specimen with the capsule intact and again after a single randomly chosen ligament was cut (N = 5 in each group). Cutting the entire inferior glenohumeral ligament resulted in the greatest increase in external rotation (10.2 degrees +/- 4.9 degrees). This was not significantly different from sectioning the coracohumeral ligament (8.6 degrees +/- 7.3 degrees). The anterior band of the inferior glenohumeral ligament (2.7 degrees +/- 1.5 degrees) and the superior and middle glenohumeral ligaments (0.7 degrees +/- 0.3 degrees) were significantly less important in limiting external rotation.

Aged↗
PubMed2005

The familial predisposition toward tearing the anterior cruciate ligament: a case control study.

PURPOSE: A study of 171 surgical cases and 171 matched controls was conducted to investigate whether a familial predisposition toward tearing the anterior cruciate ligament of the knee exists. STUDY DESIGN: Case control study; Level of evidence, 3. METHODS: Patients who were diagnosed with an anterior cruciate ligament tear were matched by age (within 5 years), gender, and primary sport to subjects without an anterior cruciate ligament tear. All 342 subjects completed a questionnaire detailing their family history of anterior cruciate ligament tears. RESULTS: When controlling for subject age and number of relatives, participants with an anterior cruciate ligament tear were twice as likely to have a relative (first, second, or third degree) with an anterior cruciate ligament tear compared to participants without an anterior cruciate ligament tear (adjusted odds ratio = 2.00; 95% confidence interval, 1.19-3.33). When the analysis was limited to include only first-degree relatives, participants with an anterior cruciate ligament tear were slightly greater than twice as likely to have a first-degree relative with an anterior cruciate ligament tear compared to participants without an anterior cruciate ligament tear (adjusted odds ratio = 2.24; 95% confidence interval, 1.24-4.00). CONCLUSIONS: Findings are consistent with a familial predisposition toward tearing the anterior cruciate ligament. CLINICAL RELEVANCE: Future research should concentrate on identifying the potentially modifiable risk factors that may be passed through families and developing strategies for the prevention of anterior cruciate ligament injuries.

Adolescent↗
PubMed2006

Anatomical double-bundle anterior cruciate ligament reconstruction after valgus high tibial osteotomy: a biomechanical study.

BACKGROUND: Although anatomical double-bundle anterior cruciate ligament reconstruction can successfully restore normal knee biomechanics for knees with typical varus-valgus alignment, the efficacy of the same reconstruction method for knees after a valgus high tibial osteotomy is unclear. HYPOTHESIS: Anatomical double-bundle anterior cruciate ligament reconstruction for valgus knees after a high tibial osteotomy cannot restore normal knee kinematics and can result in abnormally high in situ forces in the ligament graft. STUDY DESIGN: Controlled laboratory study. METHODS: Ten cadaveric knees were subjected to valgus high tibial osteotomy followed by an anatomical double-bundle anterior cruciate ligament reconstruction. The valgus knees were tested using a robotic/universal force-moment sensor system before and after the ligament reconstruction. The knee kinematics in response to anterior tibial load and combined rotatory loads, as well as the corresponding in situ forces of the anterior cruciate ligament bundles and grafts, were compared between the ligament-intact and ligament-reconstructed valgus knees. RESULTS: After reconstruction, the anterior tibial translation and internal tibial rotation for the valgus knee decreased approximately 2 mm and 2 degrees , respectively, at low flexion angles compared with those of the anterior cruciate ligament-intact knee (P < .05). The in situ forces in the posterolateral graft became 56% to 200% higher than those in the posterolateral bundle of the intact anterior cruciate ligament (P < .05). CONCLUSION: Performing an anatomical double-bundle anterior cruciate ligament reconstruction on knees after valgus high tibial osteotomy may overconstrain the knee and result in high forces in the posterolateral graft, which could predispose it to failure. CLINICAL RELEVANCE: Modifications of anterior cruciate ligament reconstruction procedures to reduce posterolateral graft force may be needed for valgus knees after a high tibial osteotomy.

Adult↗
PubMedDate not supplied

Anatomical observations on the acromioclavicular joint and supporting ligaments.

An anatomical study of the acromioclavicular (AC) joint and its supporting ligaments was performed using both macroscopic and microscopic methods. The project used 63 cadaver shoulders of unknown ages. Fifty-three joints were used for macroscopic and 10 for microscopic study. The data consisted of micrometer measurements of the dimensions of the extrinsic and intrinsic ligaments of the AC joint; measurement and description of the intraarticular meniscus and the superior and inferior capsular ligaments of the AC joint; and the anatomical course and relationship of the coracoacromial (CA) ligament to the supporting ligaments of the AC joint and a description of its insertion on the acromion process. The following observations were made: The coracoclavicular ligament, especially the trapezoid ligament, provides significant soft tissue restraints to upward displacement of the clavicle. A complete AC joint disc was found in only one, meniscoid discs in 25, remnants of discs in 16, and no discs in 11 of the 53 joints studied macroscopically. (No age correlation was made since the ages of the cadavers were unknown). The CA ligament interconnects with the inferior capsular ligament of the AC joint as well as with the coracoclavicular and coracohumeral ligaments. It also has a broad area of insertion on the inferior acromial surface. The CA ligament appears to function as a buffer between the acromion and the rotator cuff, and to provide support for the AC joint. Transection of the CA ligament may result in loss of this buffering function.

Acromioclavicular Joint↗