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PubMed1995

Extrinsic wrist ligaments in the pathomechanics of ulnar translation instability.

A description of the various combinations of ligament disruptions necessary for ulnar translation instability is presented based on a series of cadaver dissections and load studies. Dissections and load studies demonstrated that major ligament disruption, even to the extent that only the dorsal ulnolunate, the palmar ulnolunate or the radioscaphocapitate, and the long radiolunate ligaments were left intact, failed to result in meaningful ulnar translation of the carpus. The radioscaphocapitate ligament alone could not prevent significant ulnar translation. Palmar translation instability was evident with less ligament disruption than that needed for ulnar translation and was always evident if there was ulnar translation. These studies imply that ulnar translation represents a much more global ligament disruption and instability than previously suggested in the literature.

Aged↗
PubMed1991

The distal radioulnar ligaments: a biomechanical study.

The mechanical roles of the triangular fibrocartilage have been examined in three experiments. Kinematic analysis by a stereophotogrammetric method revealed that the palmar radioulnar ligament was taut in supination and that the dorsal radioulnar ligament was taut in pronation. In full pronation, the palmar radioulnar ligament decreased to an average of 71% of its length in tension. In full supination, the dorsal radioulnar ligament decreased to an average of 90% of its length. Mechanical testing of the triangular fibrocartilage under axial load disclosed a significant laxity (mean: 10.4 mm), which was decreased in pronation. Transverse loading tests demonstrated that the triangular fibrocartilage is less stiff in neutral forearm rotation. Study of the material properties of the palmar and dorsal parts of the triangular fibrocartilage showed these structures to be strong ligaments with material properties similar to those of the radiocarpal ligaments.

Biomechanical Phenomena↗
PubMed1991

Radioscapholunate ligament: a gross anatomic and histologic study of fetal and adult wrists.

The radioscapholunate ligament was studied using fifty-four dissected adult cadaver wrists. Four of these wrists had arterial perfusions with colored latex and serial sections were made of twenty-one wrists from fetuses ranging in size from 23 to 230 millimeters crown-rump length. The radioscapholunate ligament was consistently identified between the long and short radiolunate ligaments, emerging through the palmar capsule of the radiocarpal joint. It was found to be a neurovascular structure surrounded by synovial tissue with vascular origins from the anterior interosseous and radial arteries and a neural origin from the anterior interosseous nerve. On entering the radiocarpal joint it attaches proximally to the interfacet prominence on the articular surface of the radius and distally to form the proximal membrane of the scapholunate interosseous ligament system. We found no anatomic evidence that this structure should be considered a ligament in a traditional mechanical sense. However, this structure may be clinically important as the vascular supply of the scapholunate interosseous ligament, as well as a sensory pathway from the scapholunate articulation.

Adult↗
PubMed1996

The gross and histologic anatomy of the scapholunate interosseous ligament.

The scapholunate interosseous ligament, which connects the carpal scaphoid and lunate bones, was evaluated by gross dissection and serial histologic sections in transverse, sagittal, and coronal planes in 21 fresh and 16 fixed adult cadaver wrists. The scapholunate interosseous ligament is consistently divisible into three anatomic regions: dorsal, proximal, and palmar. The dorsal region is thick and composed of short, transversely oriented collagen fibers. The proximal region is principally composed of fibrocartilage, with a few superficial, longitudinally oriented collagen fibers. The proximal region may extend distally a few millimeters into the scapholunate joint space, thus resembling a knee meniscus. The radioscapholunate ligament separates the proximal and palmar regions of the scapholunate interosseous ligament, often extending distally to cover the dorsal surface of the palmar region of the scapholunate interosseous ligament. The palmar region is thin and composed of obliquely oriented collagen fascicles, just dorsal to and separate from the long radiolunate ligament.

Adult↗
PubMed1998

Anatomic study of the pisotriquetral joint: ligament anatomy and cartilagenous change.

Eighty embalmed cadaver wrists (40 right and 40 left, 55 male and 25 female, aged 36 to 93 years [average age, 72.5 years]) were dissected to assess the anatomy of the pisotriquetral joint and the location of degenerative changes. The patterns of degenerative changes were classified into five types: type 1, central (8.8%); type 2, peripheral (38.8%); type 3, fan-shaped (13.8%); type 4, mixed (combination of > or =1 of types 1, 2, and/or 3; 10.0%); and type 5, total (12.5%). There was no cartilagenous change in 16.2% of the pisoform and 13.7% of the triquetrum. Degenerative changes (exposed subchondral bone and chondromalacia) on the articular surface of the pisiform were present in 83.3% of the wrists and on the triquetrum in 86.3% of the wrists. Degenerative changes were most commonly of the type 2 pattern (peripheral), with change located most commonly in the distal, distal-radial, and radial aspects of the pisiform and triquetrum. The ligamentous anatomy was categorized into 3 different types: type A, pisohamate and pisometacarpal ligaments inserted on the palmar distal aspect of the pisiform (52.5%); type B, pisohamate ligament inserted on the radial side of the pisiform and pisometacarpal ligament inserted on the palmar side of the pisiform (41.3%); and type C, type B anatomy with an additional ligamentous slip between the pisometacarpal ligament and the distal aspect of the hook of the hamate (6.2%).

Adult↗
PubMed2002

Development of the attachment zones in the rat anterior cruciate ligament: changes in the distributions of proliferating cells and fibrillar collagens during postnatal growth.

The development of the attachment zones of the anterior cruciate ligament (ACL) is an important consideration when examining the structural properties. The aim of this study was to elucidate the morphological changes and the distribution of proliferating cells and collagen types I, II and III at the attachment zones of the rat ACL during postnatal growth. The majority of proliferating cell nuclear antigen (PCNA) immunostained cells were noted near the ligament insertion, especially at the tibial site, and these cells gradually changed to fibrochondrocyte-like cells but still produced collagen types I and III at birth until one month old when rapid longitudinal growth of the ACL took place. After one month when the rate of the ligament growth decreased to one thirtieth of that during the first month and the epiphyseal cartilage at the attachment zone had been replaced by bone, these fibrochondrocyte-like cells began to produce collagen type II and reveal safranin O staining. The immunolabelling pattern to collagen type III was similar to that of PCNA immunostaining during the growth phase. Our findings show that the fibrochondrocytes at the attachment zone may develop from the ligament cells and act as a growth zone for the ligament during the period of ligament growth, and that subsequently, these cells begin to synthesis collagen type II and proteoglycans after epiphyseal ossification. These observations mainly occurred at the tibial attachment zone.

Animals↗
PubMed1994

Disruption of the ankle syndesmosis: biomechanical study of the ligamentous restraints.

We investigated the relative importance to stability of the four component ligaments of the distal tibiofibular syndesmosis. Eight fresh-frozen cadaver specimens were tested on a hydraulic test system during sequential cutting of the ligaments. The percentage resistance to 2 mm of diastasis was measured for the four ligaments. The anterior inferior tibiofibular ligament provided 35%, interosseous ligament 22%, superficial posterior inferior tibiofibular 9%, and deep posterior inferior tibiofibular 33%. These results have clinical implications with regard to injury. Damage to the syndesmosis should be assessed anteriorly and posteriorly at the time of examination. The interosseous ligament can be visualized arthroscopically.

Ankle↗
PubMed1994

The palmar wrist ligaments revisited, clinical relevance.

In fifteen cadaver wrists and ten foetus wrists palmar ligaments were studied. As a result, the palmar scapho-triquetral ligament was presented by means of gross anatomical study, MR imaging, and histological study. A kinematic study was conducted on three cadaver wrists to analyze patterns of motion on the proximal carpal row bones based on the helical axis concept. Motion analysis showed that the scaphoid has a set of helical axes bundled at the radial side of the wrist. On the contrary, the triquetrum had axes bundled on the ulnar side, approximately in the same position as the lunate. That shows that the lunate and triquetrum are coordinated in motion and opposed to that of the scaphoid. The structure possibly ruling this pattern of motion could be the palmar scapho-triquetral ligament, whose insertions on the scaphoid and triquetrum are close to the crossing-point of the helical axes of the scaphoid and triquetrum/lunate, respectively. In order to study the clinical relevance of our findings, a prospective clinical study on 53 patients after wrist injury was conducted. All patients were clinically examined, simple and semi-stress X-rays were taken, and arthrography and arthroscopy performed. Ligament tears were often found, but any correlation to clinical findings or arthrography could not be found. However, high correlation could be found between the lesion of the palmar scapho-triquetral ligament and a DISI position of the lunate combined with increased scapho-lunate angle. It can be concluded that the tear of the palmar scapho-triquetral ligament causes instability pattern that is radiologically evident at an early stage.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1994

MRI of knee ligaments.

The stability of the knee depends on the integrity of its ligaments. Pain, clinical history, and nonspecific physical findings may hinder clinical diagnosis of acute ligamentous injury. Most major knee ligaments have uniform low signal intensity on all imaging sequences, and diagnosis of injury is based on periligamentous soft tissue edema, increased signal within the ligament, or disrupted structures. Correlation of of findings from routine sagittal, coronal, and axial MRI scans usually yields a definitive diagnosis of knee ligamentous injury. This article reviews normal anatomy, function, mechanism of injury, and normal and pathological MRI findings of the major knee ligaments.

Humans↗
PubMed2002

Spinal and supraspinal effects of activity in ligament afferents.

In this paper available knowledge on effects from joint and ligament afferents on spinal neurones and pathways are briefly reviewed, and possible functional implications discussed. Ligament afferents may contribute to joint stability, muscle coordination and proprioception through direct polysynaptic reflex effects onto ascending pathways and skeletomotoneurones, and/or indirectly via reflex actions on the gamma-muscle spindle system. Theoretical and experimental evidence indicate that ligament afferents, together with afferents from other joint structures, muscles and the skin, provide the CNS with information on movements and posture through ensemble coding mechanisms, rather than via modality specific private pathways. The existence and functional relevance of ligamentomuscular protective reflexes, that are triggered when the ligament is threatened by potentially harmful loads, has been seriously questioned. It seems more likely that peripheral sensory inputs from ligament afferents participate in a continuous control of the muscle activity through feedforward, or preprogramming, mechanisms. In line with these ideas it has been suggested that ligament mechanoreceptors have an important role in muscle coordination and in the reflex regulation of the functional joint stability, by contributing to the preprogramming of the muscle stiffness through reflex modulation of the gamma-muscle spindle system.

Afferent Pathways↗
PubMedDate not supplied

Coracoacromial ligament tension in vivo.

Tension in the coracoacromial (CA) ligament has been postulated as the mechanism of acromial spur formation. Five patients (mean age, 58 years) undergoing open rotator cuff repair were recruited. A differential variable reluctance transducer (DVRT) was inserted into the CA ligament parallel to the fiber orientation. The DVRT measured linear displacement as the glenohumeral joint was moved through 90 degrees of abduction and full internal/external rotation. The CA ligament was then removed with the DVRT in situ. The specimen was mounted on a material-testing machine. Load was applied in the line of the CA ligament fibers, and the DVRT output recorded. The CA ligament was found to be under tension, which was lowest with the arm adducted (mean, 8.9 N; range, 3.7-22 N) and highest in abduction (mean, 15.7 N; range, 6.5-38 N). This study confirms CA ligament tension in vivo as a possible stimulus for acromial spur formation.

Acromion↗
PubMedDate not supplied

Lateral collateral ligament of the elbow joint: anatomy and kinematics.

The structure and kinematics of the lateral collateral ligament of the elbow joint were investigated in 10 cadaveric specimens. The lateral collateral ligament was observed to be a distinct part of the lateral collateral ligament complex. It contains posterior fibers that pass through the annular ligament and insert on the ulna. Three-dimensional kinematic measurements in different forearm rotations showed that joint puncture induced a 1 degree joint laxity significant in forced varus from 30 degrees to 80 degrees of flexion and in forced external rotation from 30 degrees to 120 degrees of flexion. Division of the posterolateral capsule caused no further laxity. Cutting the lateral collateral ligament induced a maximum laxity of 11.8 degrees at 110 degrees of flexion in forced varus and a maximum laxity of 20.6 degrees at 110 degrees of flexion in forced external rotation. The corresponding maximal posterior radial head translation was observed at 80 degrees to 100 degrees of flexion and was 5.7 mm in forced varus and 8.1 mm in forced external rotation. This study suggests the lateral collateral ligament to be an important stabilizer of the humeroulnar joint and the radial head in forced varus and external rotation. The humeroulnar stability is independent of forearm rotation.

Aged↗
PubMedDate not supplied

The anatomy of the glenohumeral ligamentous complex and its contribution to anterior shoulder stability.

One hundred four enbalmed cadaver shoulders were evaluated. With a dorsal approach we opened the dorsal capsule after resecting the infraspinatus and teres minor muscles. For reaching the anterior capsule and the glenohumeral ligaments, the humeral head was resected. In this way we could quantify and qualify the glenohumeral ligaments and classify the synovial recesses based on the classification system of DePalma into type I to VI. Secondary signs of shoulder instability were documented. The superior glenohumeral ligament was missing in 6 (5.8%) shoulders, the middle glenohumeral ligament in 16 (15.4%) shoulders, and the inferior glenohumeral ligament in 7 (6.8%) shoulders. Most of the synovial recesses belonged to group I (38.5%) and III (46.2%). As a secondary sign of instability four shoulders had a Hill-Sachs fracture and a bony Bankart lesion. All four shoulders had no middle glenohumeral ligament and a large anterior type IV recess.

Aged↗
PubMedDate not supplied

Biomechanical characteristics of the lateral ligament of the ankle joint.

The purpose of this study was to investigate the biomechanical properties of the lateral ankle ligaments and to correlate these properties with the distribution of mechanoreceptors in the ligaments reported previously. Biomechanical tensile tests were performed by using a video dimension analyzer to monitor the distortion of the lateral ligament at the pole and center in the animals. The mean upward slope of the load-elongation curves of the pole group was 38.1+/-14.2, and that of the center group was 79.1+/-6.5. The pole of the ligaments tended to be elongated more than the center. These biomechanical results suggest that mechanoreceptors in the pole of the ligaments, compared with those in the center, may receive more mechanical stress and be effective in monitoring of tension applied to the ligament.

Animals↗
PubMed2005

Does a balance deficit persist in Australian Football players with previous lower limb ligament injury?

A history of lower limb ligament injury is a commonly-cited risk factor for another similar injury. During the acute phase of injury, there is a balancing skill deficit in the injured limb. It has been unclear as to whether this deficit persists in the medium-to-long term for previously injured Australian footballers, contributing to the risk of re-injury. This study compared the balance ability of footballers with and without previous lower limb ligament injury and, for previously injured players, the balance ability of the previously injured limb to the opposite uninjured limb. A total of 216 players from 6 teams from the Australian Football League were tested. The balance task comprised stepping on to a foam mat on top of a force plate and maintaining one-legged balance. The subjects were divided into 4 groups based on their injury history: all ankle injuries to only one limb, recent ankle injuries to only one limb (within the last 12 months), knee ligament injury only to one limb, and no previous ankle or knee ligament injury. Statistical analysis revealed that there was no significant difference between the balance scores of any of the previously injured players and those with no previous lower limb ligament injury. There was no significant difference between the balance score of the previously injured limb with the opposite uninjured limb. It appears that a balance deficit does not persist in Australian Football players with previous lower limb ligament injury.

Adolescent↗
PubMedDate not supplied

Physical characteristics of the axial interosseous ligament of the human sacroiliac joint.

BACKGROUND CONTEXT: Although the sacroiliac joint has occupied a place in medical literature since at least the eighteenth century, its role in normal function and dysfunction of the back and hip remains controversial. The controversy persists, because there is still no suitable method to study the role of stability and mobility at the sacroiliac joints in vivo. One cost-effective approach to understanding such complex, deeply placed structures is biomechanical modeling. Unfortunately, very few data on the mechanical properties of tissues in this region are currently available to modelers. PURPOSE: The objective of this preliminary project was to determine some mechanical properties of the axial interosseous ligament (AIL), and to investigate the histology of the ligament. STUDY DESIGN/SETTING: A modified split plot design was used in conjunction with descriptive statistics to identify AIL characteristics. PATIENT SAMPLE: This was a cadaveric study. OUTCOME MEASURES: The study used descriptive statistics to categorize the ultimate failure strength of the AIL, and to describe the macro-constituents of the ligament. METHODS: Eighteen sacroiliac joints were harvested from nine fresh female cadavers (age range, 54 to 92). Data from 10 joints submitted to mechanical testing are reported. The eight remaining joints were used for histologic analysis of the AIL by light microscopy. RESULTS: The AIL proved to be relatively weak, with a mean failure load of 381 N (SD 43.7N) and a peak stress of 1.73 MPa (SD 0.99 MPa). Histologically, the AIL contained significantly less collagen than most other "typical" ligaments. CONCLUSIONS: The AIL failure loads are just slightly higher than those for the ligamentum flavum in the spine, a tissue composed mainly of elastic fibers. In contrast, the AIL has negligible elastin content. Because the AIL represents about 14% of the total area of interosseous sacroiliac ligaments, its mechanical properties should be useful to modelers of the joint. In addition, it appears that injury to the AIL would do little to compromise the mechanical integrity of the sacroiliac joint. Further study of this ligament seems warranted.

Aged↗
PubMedDate not supplied

Assessment of a synthetic anterior cervical ligament in a spinal fusion model in sheep.

BACKGROUND CONTEXT: The anterior cervical ligament is routinely excised during cervical interbody fusion. Loss of this ligament may predispose to instability at the fusion site. Anterior plating restores stability but leads to a risk of stress shielding. An alternative approach would be to use a less rigid fixation system that would provide anterior support while allowing micromotion that could enhance bone healing within the fusion site. PURPOSE: To determine whether augmentation of an interbody fusion with a synthetic ligament enhances fusion. STUDY DESIGN: Prospective randomized study in a large animal model of cervical fusion. OUTCOME MEASURES: The primary outcome was evidence of interbody fusion, as determined by radiography, computed tomography (CT), histology and biomechanical testing. METHODS: Twelve skeletally mature sheep underwent single level (C2-3) anterior discectomy and interbody fusion using fresh frozen allograft. In six animals, the fusion was augmented with a braided polyethylene device rigidly fixed to C2 and C3 with screws. Sheep were euthanized 12 weeks postoperatively. Specimens were radiographed and then examined by CT. Six fusion sites (three control, three augmented) were used for nondestructive biomechanical testing to assess the stability of the fusion site. The remaining specimens were processed for undecalcified histology. RESULTS: As determined by radiography, the augmented group had 83% solid union as compared with 67% in the control group (p<.05). There was no difference regarding bone graft dislodgment between the two groups. The extension stiffness of the augmented group was significantly higher (p<.05) than that of controls, but there was no significant difference between the two groups in flexion stiffness. There was no significant difference in bone formation in the two groups as determined by CT and histology, although there was a trend for increased endochondral ossification in the augmented repairs. There was no evidence of significant adverse tissue reactions to the ligament. CONCLUSIONS: Use of a synthetic ligament was associated with a moderate increase in fusion rate and a statistically significant increase in fusion site stiffness in extension. The use of an augmentation device, such as this synthetic ligament, may be beneficial in cervical fusion, especially when multilevel surgery is being contemplated.

Animals↗
PubMed2004

Functional tissue engineering for ligament healing: potential of antisense gene therapy.

Traumatic knee injuries frequently involve the disruption of multiple ligaments, such as a complete tear of the medial collateral ligament (MCL) together with a rupture of the anterior cruciate ligament (ACL) (Miyasaka, K., D. M. Daniel, M. L. Stone, and P. Hirshman. Am. J. Knee Surg. 4:3-8, 1991). Despite the high incidence, clinical management of this type of injury is still debated. Laboratory studies have shown that the ACL and MCL share the responsibility of stabilizing the knee, especially in response to valgus and other rotatory torques as well as anterior tibial loads (Inoue, M., E. McGurk-Burleson, J. M. Hollis, and S. L-Y. Woo. Am. J. Sports Med. 15:15-21, 1987; Kanamori, A., M. Sakane, J. Zeminski, T. W. Rudy, and S. L-Y. Woo. J. Ortho. Sci. 5:567-571, 2000; Ma, C. B., C. D. Papageogiou, R. E. Debski, and S. L. Woo. Acta Orthop. Scand. 71:387-393, 2000; Sakane, M., G. A. Livesay, R. J. Fox, T. W. Rudy, T. J. Runco, and S. L-Y. Woo. Knee Surg. Sports Traumatol. Arthrosc. 7:93-97, 1999). When one structure is deficient, the force in the other increases significantly to compensate. The injured ACL does not heal and requires surgical replacement by tissue grafts. On the other hand, after an isolated MCL tear or in a combined MCL and ACL injury, the MCL can heal spontaneously without surgical intervention and can function well in most cases. Nevertheless, the biomechanical and biochemical properties as well as the histomorphological appearance of the healing MCL are substantially different to those of normal tissue (Bray, R. C., D. J. Butterwick, M. R. Daschak, and J. V. Tyberg. J. Orthop. Res. 14:618-625, 1996; Loitz-Ramage, B. J., C. B. Frank, and N. G. Shrive. Clin. Orthop.:272-280, 1997; Weiss, J. A., S. L-Y. Woo, K. J. Ohland, S. Horibe, and P. O. Newton. J. Orthop. Res. 9:516-528, 1991). In an effort to improve the outcome of injuries to these and other ligaments, therapeutic strategies associated with improving biomechanical, biochemical, and histomorphological properties of ligaments have been investigated in recent years. These therapeutic strategies include growth factor stimulation (Conti, N. A., and L. E. Dahners. Presented at Orthopaedic Research Society, San Francisco, CA; Deie, M., T. Marui, C. R. Allen, K. A. Hildebrand, H. I. Georgescu, et al. Mech. Ageing Dev. 97:121-130, 1997), cell therapy (Menetrey, J., C. Kasemkijwattana, C. S. Day, P. Bosch, F. H. Fu, et al. Tissue Eng. 5:435-442, 1999; Watanabe, N., S. L-Y. Woo, C. Papageorgiou, C. Celechovsky, and S. Takai. Microsc. Res. Tech. 58:39-44, 2002), as well as gene stherapy (Nakamura N., D. A. Hart, R. S. Boorman, Y. Kaneda, N. G. Shrive, et al. J. Orthop. Res. 18:517-523, 2000; Shimomura, T., F. Jia, C. Niyibizi, and S. L-Y. Woo. Connect. Tissue Res.:2003). The knowledge gained by studying these therapeutic strategies could potentially be applied to other ligaments and tendons. In this article, antisense gene therapy to alter gene expression by using antisense oligonucleotides will be examined as a possible solution.

Animals↗