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In vitro testing protocols for the cruciate ligaments and ligament reconstructions.

The techniques that have been used to characterize the biomechanical behavior of the knee, cruciate ligaments, and cruciate ligament replacements differ, making comparisons between studies difficult or, at times, impossible. Therefore, it is important to standardize the testing protocols and techniques that describe the biomechanical behavior of the knee and cruciate ligaments. This will allow investigators to express opinions with respect to the interpretation of data, rather than based on differences between testing techniques. Standardized techniques are proposed to locate the origins of the tibial and femoral coordinate systems, and thus, allow comparisons of knee kinematics (e.g., displacements and rotations) between investigations. Standard techniques that can be used to measure the load-displacement behavior of the knee are described, and important considerations that should be appreciated with respect to preparing and testing of the joint are summarized. It is important to evaluate the single cycle load-to-failure characteristics and the cyclic loading response of an anterior cruciate ligament graft, and techniques to evaluate cruciate ligament graft fixation are proposed. The strengths of different models to characterize the biomechanical behavior of the knee are reviewed.

Anterior Cruciate Ligament↗

Dissection of the cardinal ligament in radical hysterectomy for cervical cancer with emphasis on the lateral ligament.

Surgical experience with carcinomas of the uterus and rectum has provided new insights into the surgical anatomy of a lamina, which separates the paravesical space from the pararectal space. It has been proved that each of the lamina consists of the cardinal and lateral ligaments and pelvic splanchnic nerves, descending in the following order. The cardinal and lateral ligaments, as a connective stalk, insert into the lateral walls of the uterus and rectum extending from the inner aspect of the pelvic wall. Clarification of this structural relationship led to the development of a new procedure for the dissection of the cardinal ligament in radical hysterectomy, while still preserving the lateral ligament. This facilitated systematic dissection of the cardinal and uterosacral ligaments with posterior manipulation, leading to a reduction in blood loss and to prevention of brisk bleeding from the venous plexuses.

Dissection↗

Measurement of the mechanical properties of the ovine anterior cruciate ligament bone-ligament-bone complex: a basis for prosthetic evaluation.

The reported ultimate tensile stress of the anterior cruciate ligament varies greatly, ranging from 13 to 147 MPa. This study shows that the orientation and degree of flexion of the bone-ligament-bone complex significantly alter the apparent ultimate tensile properties (ultimate tensile stress ranging from 60 +/- 3 to 123 +/- 15 MPa, ultimate specific extension from 37 +/- 7 to 93 +/- 20%), whilst the method chosen for measuring extension also affects the calculated specific extension of the bone-ligament-bone complex. It is suggested that, for considerations of prosthesis design and evaluation, the mechanical properties of the bone-ligament-bone complex should be measured in anterior draw and extension measured using points as close as possible to the positions of the ligamentous attachment sites.

Animals↗

Changes in knee laxity and ligament force after sectioning the posteromedial bundle of the posterior cruciate ligament.

PURPOSE: Our purpose was to evaluate the role of the posteromedial (PM) bundle of the native posterior cruciate ligament (PCL) in restraining posterior tibial translation and the effects of sectioning of the PM bundle on PCL forces. METHODS: The PCL's femoral origin was mechanically isolated by use of a cylindrical coring cutter, and a cap of bone containing the ligament fibers was attached to a load cell that recorded resultant force in the ligament as the knee was passively extended from 120 degrees to 0 degrees without and with simulated tibial loading conditions. Anteroposterior laxity was also measured after load cell installation. The PM bundle was cut at its femoral origin, and all tests were repeated. RESULTS: Cutting the PM bundle produced small but statistically significant increases in mean laxity at 0 degrees (+1.06 mm) and 10 degrees (+0.83 mm) of flexion; mean laxities at 30 degrees, 45 degrees, 70 degrees, and 90 degrees were unchanged. Forces in the remaining anterolateral bundle were not significantly different from those in the intact ligament for any mode of tibial loading, with the exception of the valgus moment, where sectioning of the PM bundle significantly reduced the PCL force at 0 degrees and 5 degrees of flexion. CONCLUSIONS: The relatively small increases in mean laxity after cutting of the PM bundle show that it plays a minor role in restraining posterior tibial translation. The minor changes in ligament force profiles after cutting of the PM bundle indicate that the remaining anterolateral bundle fibers continued to be loaded in a near-normal fashion. CLINICAL RELEVANCE: This study helps to elucidate the function of the PM bundle in the native PCL. Because only small changes were seen in the biomechanical parameters tested, the rationale for reconstructing this bundle of the PCL could be questioned.

Adult↗

Ligament balancing in TKA: evaluation of a force-sensing device and the influence of patellar eversion and ligament release.

Ligament balancing in total knee arthroplasty may have an important influence on joint stability and prosthesis lifetime. In order to provide quantitative information and assistance during ligament balancing, a device that intraoperatively measures knee joint forces and moments was developed. Its performance and surgical advantages were evaluated on six cadaver specimens mounted on a knee joint loading apparatus allowing unconstrained knee motion as well as compression and varus-valgus loading. Four different experiments were performed on each specimen. (1) Knee joints were axially loaded. Comparison between applied and measured compressive forces demonstrated the accuracy and reliability of in situ measurements (1.8N). (2) Assessment of knee stability based on condyle contact forces or varus-valgus moments were compared to the current surgical method (difference of varus-valgus loads causing condyle lift-off). The force-based approach was equivalent to the surgical method while the moment-based, which is considered optimal, showed a tendency of lateral imbalance. (3) To estimate the importance of keeping the patella in its anatomical position during imbalance assessment, the effect of patellar eversion on the mediolateral distribution of tibiofemoral contact forces was measured. One fourth of the contact force induced by the patellar load was shifted to the lateral compartment. (4) The effect of minor and major medial collateral ligament releases was biomechanically quantified. On average, the medial contact force was reduced by 20% and 46%, respectively. Large variation among specimens reflected the difficulty of ligament release and the need for intraoperative force monitoring. This series of experiments thus demonstrated the device's potential to improve ligament balancing and survivorship of total knee arthroplasty.

Aged↗

Nitric oxide and metalloproteinases in canine articular ligaments: a comparison between the cranial cruciate, the medial genual collateral and the femoral head ligament.

Osteoarthritis due to cranial cruciate ligament (CCL) rupture or hip dysplasia is one of the most important causes of chronic lameness in dogs. This study aimed at comparing nitric oxide (NO) production by the CCL with that of the femoral head ligament (FHL) and the medial collateral ligament (MCL), and investigating the pathway of NO production and the concomitant metalloproteinase (MMP) activity in the presence or absence of an inflammatory stimulus. Ligaments of normal dogs were subjected to different stimuli, and NO and MMP activity from explant culture supernatants were compared. The results showed that in explant cultures of the canine CCL more NO was produced than in those of the other two ligaments. A higher level of NO was produced when CCLs were exposed to the inducible nitric oxide synthase (iNOS)-inducing cocktail TNF/IL-1/LPS, and NO synthesis could be inhibited by both l-NMMA, a general nitric oxide synthase (NOS) inhibitor and l-NIL, a specific iNOS inhibitor. However, a correlation between NO synthesis and iNOS expression levels as determined by immunohistochemistry was not observed. In contrast to CCL, no evidence for iNOS-dependent NO synthesis was observed for MCL and FHL. The CCL produced less MMP than MCL and FHL, and no correlation between MMP and NO could be demonstrated. MMP activity in the CCL increased significantly after 48 h of incubation with the inflammatory stimulus. The results suggest that in canine osteoarthritis NO synthesized by canine CCL plays a more important role in the pathogenesis of osteoarthritis of the stifle than that synthesized by FHL and MCL.

Animals↗

Ipsilateral knee ligament injuries and open tibial diaphyseal fractures: incidence and nature of knee ligament injuries sustained.

Fifty patients with isolated open tibial shaft fractures were reviewed to determine the incidence and type of knee ligament injuries sustained. Eighteen patients (36 per cent) had at least one ligament injury in the ipsilateral knee; eight had multiple ligament injuries. Only four patients (22 per cent) were diagnosed as having a ligament injury at the time of initial management and the remaining 14 patients were diagnosed at the time of review for this study. There is a high incidence of ipsilateral knee ligament injuries in open tibial shaft fractures; the knee should be thoroughly examined at the time of initial fracture management.

Adult↗

Reconstruction of the scapholunate ligament in a cadaver model using a bone-ligament-bone autograft from the foot.

This study is an investigation of a new procedure in which the scapholunate interosseous ligament (SLIL) is reconstructed using a bone-ligament-bone autograft from the foot. After investigation, the dorsal medial portion of the navicular-first cuneiform ligament (NFCL) was chosen for testing as a potential donor since it is similar in length and thickness to the SLIL and it is easily harvested with minimal potential donor site morbidity. Eight SLILs and NFCLs were harvested from fresh-frozen cadavers. Biomechanical extensometry testing was performed using an Instron 1000 machine. A 5-mm-wide central portion of the NFCL was tested since this width was compatible with the technical aspects of reconstructing the SLIL. Both ligaments were tested for elastic properties, including stiffness, load to failure, and deformation to failure. Mean length of the NFCL was 7.6 mm (range, 5.5-8.5 mm). Stiffness of the NFCL was 10.6 x 10(5) Nm (range, 8.0-13.0 Nm) compared with 14.4 x 10(5) Nm for the SLIL (range, 10.0-19.5 Nm). Peak load to failure for the NFCL was 1,980 N (range, 1,530-2,940 N) compared with 2,940 N for the SLIL (range, 1,780-4,050 N). Total elongation to failure for the NFCL was 2.50 mm (range, 1.7-3.2 mm) compared with 3.2 mm for the SLIL (range, 2.1-5.2 mm). Thus, the biomechanical characteristics of the NFCL were found to be very similar to those of the SLIL. Having established the biomechanical similarities of the 2 ligaments, we are currently using the NFCL to reconstruct the sectioned SLIL in a fresh-frozen cadaver model. Early results suggest that this procedure is feasible for restoration of normal kinematics of the wrist.

Aged↗

Mechanisms of anterior cruciate ligament neovascularization and ligamentization.

Columbia-Rambouillet cross-bred sheep were used to study the revascularization and ligamentization process of anterior cruciate ligament (ACL) reconstruction over a 6-month period using basic histology, immunohistochemistry, and electron microscopy. The reconstruction technique studied was a quadruple-hamstring, interference screw fixation technique. Further, these specimens, after retrieval at 6, 12, and 26 weeks, were compared with human arthroscopic 'second looks' and with 10 en bloc specimens obtained when a cruciate-sacrificing total knee replacement was performed. The study showed that, with this reconstruction technique, Sharpey's fibers were seen at 6 weeks in both sheep and human specimens. The intratunnel specimens showed proliferative chondrification, then ossification of the matrix. Intra-articular neovascularization, ligamentization, and junction ossification occurred. Myoblasts or smooth muscle cells appear to mediate the ligamentization as evidenced in electron microscopy by proliferate collagen manufacture. These myoblasts were seen in both the healing sheep and human second looks, but not seen in mature ACL grafts or in normal ACLs. At 6 months postoperatively, the sheep ACL reconstruction appeared clinically, histologically, and immunohistochemically indistinguishable from the normal sheep ACL. A correlation of this work with published animal studies in which biomechanical testing was performed and with human 'second looks' would imply that an ACL reconstruction may be vulnerable during this period of neovascularization and ligamentization.

Adult↗

The corporo-glans ligament: description and functional significance of a ligament connecting the corpora cavernosa to the glans penis.

The two corpora cavernosa (CC) end blindly under cover of the glans penis (GP). The method of attachment of the CC to the GP could not be traced in the literature. The current communication investigated the hypothesis of a ligamentous attachment existing between the two corporal ends and the GP. In all, 18 male cadaveric specimens were studied by direct dissection and histologically. Six were neonates and 12 adults (mean age 32.3+/-10.6 s.d. y). After examining and photographing the connection between the CC and GP, sagittal, parasagittal, and coronal sections of the connection were stained and studied microscopically. A triangular fibrous tissue band connected the distal blind ends of the two CC with the GP. The base of this band was attached to the tunica albuginea of the two CC, while the apex was continuous with the fibrous septa between the sinusoids of the cavernous tissue of the GP. Microscopically, the ligament consisted of collagen and elastic fibers; in some sections, the collagen fibers of the tunica albuginea were continuous with those of the band. A band of collagen and elastic fibers could be identified connecting the two CC to the GP; we term it the 'corporo-glans ligament'. This ligament presumably affords the connection with rigidity, flexibility, and tissue strength. We suggest that it firmly connects the GP to the CC during penile thrusting. Further studies are required to assess the possible role of this ligament in erectile dysfunction.

Adolescent↗

[Scapholunate dissociation. Results of ligament suture and ligament-plasty].

The diagnosis of scapholunate ligament rupture is frequently missed. Untreated, it will lead to carpal collapse and arthrosis of the wrist, and ultimately to scapholunate advanced collapse (SLAC-wrist). We report the results of 20 patients treated either by direct suture or reconstruction of the ligament with a follow-up of three to five years after surgery. The operation was performed between 0.5 and 120 months (suture 2.6 months, reconstruction 28 months) after the original trauma. The results of direct repair were superior to ligament reconstruction. In our experience, direct ligament repair was only possible up to four to six months after trauma, this study emphasizes the importance of early diagnosis and treatment by anatomical reposition of scapholunate ligament rupture.

Adult↗

[Cruciate ligament reconstruction in knees with congenital cruciate ligament aplasia].

INTRODUCTION: The absence of the cruciate ligament is a rare pathology which is described as a congenital entity often being bilateral and in combination with other malformations. Patients mostly deny symptoms of instability but demonstrate signs of laxity. There is not a standardized treatment yet. METHODS: We report a case of congenital cruciate ligament aplasia which was treated with an ACL reconstruction. RESULTS: In the described case, the patient had a bad clinical result after ACL reconstruction with a fixed posterior subluxation of the tibia. Resection of the ACL reconstruction and physical therapy led to a better clinical result. DISCUSSION: While some authors report favourable results with cruciate ligament reconstruction, others report good results with a conservative regime of symptomatic treatment. When patients do not complain of instability conservative treatment might be one option, since the knee joint is adjusted to this abnormality. Surgical treatment should be considered when conservative therapy is frustrane. If however reconstructive surgery is done in cruciate ligament aplasia both cruciate ligaments need to be reconstructed. After isolated ACL reconstruction the tibia might be fixed posteriorly, leading to extension problems and severe patellofemoral pain as seen in our case.

Anterior Cruciate Ligament↗

Arthrographic differential diagnosis between ruptures of the anterior talofibular ligament, the joint capsule and the anterior tibiofibular ligament.

From literature study, surgical findings and cadaver experiments, it is unlikely that, in an inversion type ankle sprain, rupture of the anterior tibiofibular ligament frequently accompanies rupture of the capsule and the lateral ligaments. Contrary to the experience of other authors, we found the presence or absence of a) a contrast-free zone, b) the tibiofibular recess, or c) both together, on ankle arthrography in no way indicative of a rupture of the anterior tibiofibular ligament. Contrast leakage out of the joint into the soft tissues without leakage below and lateral to the lateral malleolus indicates rupture of the joint capsule. Leakage below and lateral to the lateral malleolus indicates rupture of the anterior talofibular ligament. The anatomic relationships between the syndesmosis, the joint capsule, the tibiofibular recess and the anterior talofibular recess and the anterior talofibular ligament were studied on cadavers and during surgery. Contrast spread in the soft tissues is probably determined by the arrangement of and damage to the soft tissues and by the size of the haematoma and follows the path of least resistance.

Ankle Injuries↗

Anterior oblique ligament reconstruction of the thumb using the transverse carpal ligament: description of a new procedure.

Traumatic dislocation of the thumb carpometacarpal joint is an uncommon injury that may have long-term sequelae after treatment. Joint instability may cause pain, weakness of pinch, and the increased likelihood of development of posttraumatic arthritis. The anterior oblique ligament has generally been accepted as the most important static stabilizer of the trapeziometacarpal joint. Numerous operative techniques have been described to reconstruct this ligament. The author introduces a novel operative procedure to reconstruct the anterior oblique ligament of the thumb using the transverse carpal ligament (AOLR-T). This procedure was performed on 5 fresh-frozen cadaveric hands to assess its feasibility and potential efficacy. No technical difficulties were encountered. AOLR-T may be indicated for the treatment of thumb carpometacarpal instability of primary or secondary etiology and may avoid many of the disadvantages of traditional ligament reconstruction.

Cadaver↗

The intercarpal ligaments of the equine midcarpal joint, Part 1: The anatomy of the palmar and dorsomedial intercarpal ligaments of the midcarpal joint.

OBJECTIVE: To describe in detail the structure of the medial palmar intercarpal ligament (MPICL), the lateral palmar intercarpal ligament (LPICL), and a dorsomedial intercarpal ligament (DMICL) of the equine midcarpal joint. STUDY DESIGN: Dissections of equine midcarpal joints. ANIMALS AND SAMPLE POPULATION: Ten carpal joints from eight thoroughbred horses. METHODS: Detailed dissections of the midcarpal joint were performed, with particular attention paid to the MPICL, the LPICL, and the DMICL. The attachments and dimensions of these structures were recorded, as well as their behavior during joint movement. RESULTS: The DMICL arose from the dorsomedial surface of the radial carpal bone (CR) and coursed palmarodistally to insert on the dorsomedial aspect of the second carpal bone (C2). The LPICL attached proximally predominantly on the distal part of the palmaromedial surface of the ulnar carpal bone (CU). From here the ligament coursed distomedially and slightly palmarly to the proximal palmarolateral surface of the third carpal bone (C3). The structure of the MPICL was complex. It attached proximally to the distolateral surface of the CR and distally to the proximal palmaromedial surface of C3, and the proximal palmarolateral aspect of the C2. It could be divided into four fiber bundles in all carpi. The predominant direction of fibers was dorsoproximal to palmarodistal, whereas the palmaromedial bundle coursed palmaroproximal to dorsodistal. CONCLUSIONS: The orientation of their fibers indicate that the MPICL and DMICL primarily resist dorsomedial displacement of CR, whereas the LPICL resists dorsolateral displacement of the CU and intermediate carpal bone. CLINICAL RELEVANCE: An understanding of the structure of the intercarpal ligaments of the midcarpal joint is important in interpreting their function and the reasons for damage to their structure.

Animals↗

Dacron ligament reconstruction for chronic anterior cruciate ligament insufficiency.

We report the 5-year follow-up results of a prospective, multicenter study evaluating the use of a Dacron prosthetic ligament in reconstruction of anterior cruciate-deficient knees. The study group consisted of 84 patients, followed for at least 5 years. The patients were divided into 2 groups: 50 patients with isolated anterior cruciate ligament laxity (Group 1) and 34 patients with a failed previous anterior cruciate ligament surgery or combined laxities (Group 2). Two surgical techniques were employed: reconstruction through drill holes in the tibia and femur (30 patients) and reconstruction using the over-the-top position with the Dacron ligament wrapped in a strip of iliotibial band (54 patients). The overall failure rate was 35.7% at 5 years. The failure rate at 2 years was 20%, illustrating a significant deterioration of results between the two follow-up intervals. Evaluation of subjective criteria using the Lysholm score showed an improvement from preoperative status at the 2-year followup; however, there was a slight decline when 5-year results were evaluated. Tegner activity levels increased from a mean of 2.9 +/- 2.1 at the preoperative visit, to a mean of 4.9 +/- 2.0 at the 2-year followup and a mean of 5.0 +/- 2.0 at the 5-year visit. These results show that the Dacron ligament prosthesis achieves the short-term goal of restoring stability and improving function and may be sufficient to provide long-term stability for the anterior cruciate-deficient knee.

Adolescent↗

Myofibroblasts in the accessory ligament (distal check ligament) and the deep digital flexor tendon of foals.

OBJECTIVE: To demonstrate myofibroblasts in the accessory ligament of the deep digital flexor tendon (ie, distal check ligament) and deep digital flexor tendon of clinically normal foals. SAMPLE POPULATION: Tissue specimens from 25 foals that were necropsied for reasons unrelated to this study and unrelated to musculoskeletal disease. PROCEDURE: The distal check ligament and deep digital flexor tendon of both forelimbs were examined histologically. Myofibroblasts were identified by immunohistochemical staining specific for alpha-smooth muscle actin (alpha-SMA). RESULTS: Most of the cells in the distal check ligament and deep digital flexor tendon of all foals stained positive for alpha-SMA. CONCLUSION AND CLINICAL RELEVANCE: Myofibroblasts made up most of the cells in the distal check ligament and deep digital flexor tendon of clinically normal foals. These cells have contractile ability and therefore, may play a role in flexure contracture of these tendons. The ability of tetracycline to chelate calcium or decrease the expression of the contractile protein alpha-smooth muscle actin could inhibit the myofibroblasts' ability to contract, thus providing a rationale for tetracycline administration as a treatment of distal interphalangeal joint flexor deformity in foals.

Actins↗

Replacement of the anterior cruciate ligament with a polyethylene prosthetic ligament.

The results of insertion of the Richards Polyflex ligament in 9 patients to replace the anterior cruciate ligament are reported. In 3 of these 9 patients it had been necessary to remove the prosthetic ligament and in another patient the operation had not stabilized the knee. Half of the patients who still have a Polyflex ligament complained of pain. It is concluded that from the material-technical point of view the Polyflex ligament has not yet been satisfactorily developed, and the operation poses a great many technical problems. Technically and functionally this system must still be considered to be in the experimental stages and not yet properly developed for general use.

Follow-Up Studies↗