MRI depiction and 3D visualization of three anterior cruciate ligament bundles.

The anterior cruciate ligament (ACL) is divided into three fiber bundles (AM-M: anteromedial-medial, AM-L: anteromedial-lateral, PL: posterolateral). We attempted to depict the three bundles of the human ACL on MRI images and to obtain 3-dimensional visualization of them. Twenty-four knees of healthy volunteers (14 males, 10 females) were scanned by 3T-MRI using the fat suppression 3D coherent oscillatory state acquisition for the manipulation of imaging contrast (FS 3D-COSMIC). The scanned images were reconstructed after the isotropic voxel data, which allows the images to be reconstructed in any plane, was acquired. We conducted statistical examination on the identification rate of the three ACL bundles by 2D planes. Segmentation and 3D visualization of the fiber bundles using volume rendering were performed. The triple-bundle ACL was best depicted in the oblique axial plane. While the AM-M and AM-L bundles were clearly depicted in all cases, the PL bundle was not clearly visualized in two knees (8%). Therefore, the three ACL bundles were depicted in 22 knees (92%). The results of 3D visualization of the fiber arrangement agreed well with macroscopic findings of previous anatomical studies. 3T-MRI and the isotropic voxel data from FS 3D-COSMIC made it possible to demonstrate the identifiable depiction of three ACL bundles in nearly all cases. 3D visualization of the bundles could be a useful tool to understand the ACL fiber arrangement. Clin. Anat. 30:276-283, 2017. 2016 The Authors. Clinical Anatomy published by Wiley Periodicals, Inc. on behalf of American Association of Clinical Anatomists.

Mechanical functions of the three bundles consisting of the human anterior cruciate ligament.

PURPOSE: The reconstruction technique to individually reconstruct multi-bundles of the anterior cruciate ligament (ACL) has been improved in the last decade. For further improvement of the technique, the present study was conducted to determine the force sharing among the three bundles (the medial and lateral bundles (AMM and AML) of the anteromedial (AM) bundle and the posterlateral (PL) bundle) of the human ACL in response to hyperextension, passive flexion-extension and anterior force to the knee. METHODS: Using a 6-DOF robotic system, the human cadaveric knee specimens were subjected to hyperextension, passive flexion-extension and anterior-posterior tests, while recording the 6-DOF motion and force/moment of the knees. The intact knee motions recorded during the tests were reproduced after sequential bundle transection to determine the bundle forces. RESULTS: The bundle forces were around 10 N at 5 N-m of hyperextension and remained less than 5 N during passive flexion-extension. In response to 100 N of anterior force, the AMM and PL bundle forces were slightly higher than the AML bundle force at full extension. The AMM bundle force remained at a high level up to 90° of flexion, with significant differences versus the AML bundle force at 15°, 30° and 60° of flexion and the PL bundle force at 90° of flexion. CONCLUSION: The AMM bundle is the primary stabilizer to tibial anterior drawer through wide range of motion, while the AML bundle is the secondary stabilizer in deep flexion angles. The PL bundle is the crucial stabilizer to hyperextension as well as tibial anterior drawer at full extension.

Morphological analysis of the femoral trochlea in patients with recurrent dislocation of the patella using three-dimensional computer models.

We investigated the three-dimensional morphological differences of the articular surface of the femoral trochlea in patients with recurrent dislocation of the patella and a normal control group using three-dimensional computer models. There were 12 patients (12 knees) and ten control subjects (ten knees). Three-dimensional computer models of the femur, including the articular cartilage, were created. Evaluation was performed on the shape of the articular surface, focused on its convexity, and the proximal and mediolateral distribution of the articular cartilage of the femoral trochlea. The extent of any convexity, and the proximal distribution of the articular cartilage, expressed as the height, were shown by the angles about the transepicondylar axis. The mediolateral distribution of the articular cartilage was assessed by the location of the medial and lateral borders of the articular cartilage. The mean extent of convexity was 24.9 degrees sd 6.7 degrees for patients and 11.9 degrees sd 3.6 degrees for the control group (p < 0.001). The mean height of the articular cartilage was 91.3 degrees sd 8.3 degrees for the patients and 83.3 degrees sd 7.7 degrees for the control group (p = 0.03), suggesting a wider convex trochlea in the patients with recurrent dislocation of the patella caused by the proximally-extended convex area. The lateral border of the articular cartilage of the trochlea in the patients was more laterally located than in the control group. Our findings therefore quantitatively demonstrated differences in the shape and distribution of the articular cartilage on the femoral trochlea between patients with dislocation of the patella and normal subjects.

In vivo movement analysis of the patella using a three-dimensional computer model.

We used three-dimensional movement analysis by computer modelling of knee flexion from 0 degrees to 50 degrees in 14 knees in 12 patients with recurrent patellar dislocation and in 15 knees in ten normal control subjects to compare the in vivo three-dimensional movement of the patella. Flexion, tilt and spin of the patella were described in terms of rotation angles from 0 degrees . The location of the patella and the tibial tubercle were evaluated using parameters expressed as percentage patellar shift and percentage tubercle shift. Patellar inclination to the femur was also measured and patellofemoral contact was qualitatively and quantitatively analysed. The patients had greater values of spin from 20 degrees to 50 degrees , while there were no statistically significant differences in flexion and tilt. The patients also had greater percentage patellar shift from 0 degrees to 50 degrees , percentage tubercle shift at 0 degrees and 10 degrees and patellar inclination from 0 degrees to 50 degrees with a smaller oval-shaped contact area from 20 degrees to 50 degrees moving downwards on the lateral facet. Patellar movement analysis using a three-dimensional computer model is useful to clearly demonstrate differences between patients with recurrent dislocation of the patella and normal control subjects.

Comparison between the cross-sectional area of bone-patellar tendon-bone grafts and multistranded hamstring tendon grafts obtained from the same patients.

This study intraoperatively compared the cross-sectional area (CSA) and graft-tunnel fit of bone-patellar tendon-bone (BTB) and multistranded hamstring tendon (STG) grafts harvested from the same patient. Twenty-two patients with a mean age of 26 years were the subjects of the study. Each BTB graft was harvested from the central third of the patellar tendon. Tripled or quadrupled semitendinosus tendon with or without gracilis tendon was used as a STG graft. CSAs of both grafts in the same patients were intraoperatively measured using a custom-made area micrometer during primary ACL reconstruction and revision surgery or during combined ACL and PCL reconstruction. Graft-tunnel fit was calculated by dividing the CSA of the graft by that of the tibial bone tunnel. The average CSA of STG grafts was significantly greater than that of BTB grafts. The average value of graft-tunnel fit for the STG grafts% was also greater than that of the BTB grafts%. Thus STG grafts have a larger CSA and closer graft-tunnel fit than BTB grafts in a clinical setting.

Single- versus bi-socket anterior cruciate ligament reconstruction using autogenous multiple-stranded hamstring tendons with endoButton femoral fixation: A prospective study.

PURPOSE: This prospective study was conducted to compare the single-socket and the bi-socket anterior cruciate ligament (ACL) reconstruction techniques in terms of outcome. TYPE OF STUDY: Nonrandomized control trial. METHODS: There were 160 consecutive patients with unilateral chronic ACL insufficiency who underwent endoscopic single- or bi-socket ACL reconstruction alternately using multiple-stranded medial hamstring tendon and EndoButton (Smith & Nephew, Andover, MD) femoral fixation. All patients underwent the same postoperative rehabilitation protocol. Of them, 106 patients (57 single, 49 bi) were available for 2-year follow-up. RESULTS: According to the IKDC Knee Ligament Evaluation Form, 23 patients (40%) of the single-socket group were subjectively graded as normal, 30 (53%) as nearly normal, and 4 (7%) as abnormal. Twenty-six patients (53%) of the bi-socket group were graded as normal, 21 (43%) as nearly normal, and 2 (4%) as abnormal (P =.19). The mean side-to-side anterior laxity difference (KT-1000 manual maximum force) was 0.9 +/- 1.8 mm for the single-socket group and 0.7 +/- 1.2 mm for the bi-socket group (P =.44). Fifty-three of 57 patients (93%) in the single-socket group and all patients in the bi-socket group showed anterior laxity differences of +/-3 mm or less (P =.12). There were no differences in thigh muscle strength between the groups. CONCLUSIONS: Both single- and bi-socket ACL reconstruction using autogenous multiple-stranded hamstring tendons with EndoButton fixation provided satisfactory anterior stability, and there were no statistically significant differences in subjective results or measured restored stability between the 2 groups.

Human meniscus cell: characterization of the primary culture and use for tissue engineering.

Human meniscus cells from 47 surgically excised menisci were grown in primary culture. Cell proliferation and morphologic features were evaluated in three different culture media. Human meniscus cells showed three distinguishable cell types in monolayer culture: elongated fibroblastlike cells, polygonal cells, and small round chondrocytelike cells. These cells proliferated in Dulbecco's modified Eagle's medium, but by Day 7, elongated fibroblastlike cells became predominant. Cells did not proliferate in Ham's nutrient mixture-F-12. In a mixture of Ham's nutrient mixture-F-12 and Dulbecco's modified Eagle's medium, cells proliferated, maintaining their morphologic features and their ability to express messenger ribonucleic acids for aggrecan and Types I, II, and III collagen. Hyaluronan enhanced cellular proliferation without altering morphologic features or chondroitin sulfate production. Cultured human meniscus cells attached to a porous collagen sponge after cell seeding. Gene transfer was successful and an introduced gene was expressed by the cells, indicating that human meniscus cells can undergo gene manipulation. The finding that cells collected from small surgical specimens of human meniscus could be cultured, propagated, and seeded onto a collagen scaffold holds promise for the development of a cell-based, tissue engineered collagen meniscus.

Single- versus two-femoral socket anterior cruciate ligament reconstruction technique: Biomechanical analysis using a robotic simulator.

PURPOSE: Although anterior cruciate ligament (ACL) reconstruction with multistrand autogenous hamstring tendons has been widely performed using a single femoral socket (SS), it is currently advocated to individually reconstruct 2 bundles of the ACL using 2 femoral sockets (TS). However, the difference in biomechanical characteristics between them is unknown. The objective of this study was to clarify their biomechanical differences. TYPE OF STUDY: This is a cross-over trial using cadaveric knees. METHODS: Seven intact human cadaveric knees were mounted in a robotic simulator developed in our laboratory. By applying anterior and posterior tibial load up to +/- 100 N at 0 degrees, 15 degrees, 30 degrees, 60 degrees, and 90 degrees of flexion, tibial displacement and load were recorded. After cutting the ACL, the knees underwent ACL reconstruction using TS, followed by that using SS, with 44 or 88 N of initial grafts tension at 20 degrees of flexion. The above-mentioned tests were performed on each reconstructed knee. RESULTS: The tibial displacement in the TS technique was significantly smaller than that in the SS at smaller flexion angles in response to anterior and posterior tibial load of +/- 100 N, and the in situ force in the former was significantly greater than that in the latter at smaller flexion angles. Furthermore, in the TS technique, the posterolateral graft acted dominantly in extension, while the anteromedial graft mainly resisted against anterior tibial load in flexion. However, in the SS technique, the anteriorly located graft functioned more predominantly than the posteriorly located graft at all flexion angles. CONCLUSIONS: The ACL reconstruction via TS using quadrupled hamstring tendons provides better anterior-posterior stability compared with the conventional reconstruction using a single socket.

Endoscopic reconstruction of the anterior cruciate ligament with quadrupled hamstring tendons. A correlation between MRI changes and restored stability of the knee.

A total of 30 patients who underwent endoscopic reconstruction of the anterior cruciate ligament using quadrupled hamstring tendons, through a single drill hole in the femur, had MRI 24 to 28 months after operation. In 18 patients the scans revealed that both the anterior and posterior portions of the graft ran in parallel from the inside of the femoral to the tibial tunnel. In 12, the posterior bundle had moved anteriorly and the anterior bundle could not be identified at the anterodistal border of the femoral tunnel. The mean difference in the anterior laxity, when compared with the contralateral knee, was 2.0+/-1.7 mm and 4.3+/-2.8 mm for the two types, respectively. Damage to the anterior bundle may occur when using the endoscopic technique because of biomechanical disadvantages, including concentration of loading and repetitive bending stress in the anterior bundle at the opening of the femoral tunnel.

Survey on occupational health management of VDT workers among 84 Japanese companies.

This survey of 84 companies described the present status of occupational health management of VDT workers in Japan, in relation to the official Guideline (Guidelines on Occupational Health for VDT Work, 1985). The majority admitted 80% or more of their workers engage in VDT works. Four hours of VDT work per day was widely used as a criteria for the eligibility to the VDT health examination. Some specific measurement was performed at health examination among 54.8% of the companies. The most popular item was "near vision." A larger number of follow-up measures was performed with ophthalmic cases than with muscloskeletal cases. From these findings, with consideration to the results of the preceding literatures, we made 8 suggestions for the on-going revision of the Guideline: 1) including recommendation for flat panel display and portable computers, 2) widening target of VDT health education also to general workers, 3) clarification of the categorization of VDT workers, 4) offering practical measures to secure off VDT period, 5) use of subjective symptoms to screen high-risk workers, 6) supply of the latest scientific information on each measuring item, 7) periodical revision to provide state-of-the-art management, and 8) clear statement of the purpose and limitation of the Guideline.

Decorin antisense gene therapy improves functional healing of early rabbit ligament scar with enhanced collagen fibrillogenesis in vivo.

Injured ligaments heal with scar tissue, which has mechanical properties inferior to those of normal ligament, potentially resulting in re-injury, joint instability, and subsequent degenerative arthritis. In ligament scars, normal large-diameter collagen fibrils have been shown to be replaced by a homogenous population of small collagen fibrils. Because collagen is a major tensile load-bearing matrix element and because the proteoglycan decorin is known to inhibit collagen fibrillogenesis, we hypothesized that the restoration of larger collagen fibrils in a rabbit ligament scar, by down-regulating the proteoglycan decorin, would improve the mechanical properties of scar. In contrast to sense and injection-treated controls, in vivo treatment of injured ligament by antisense decorin oligodeoxynucleotides led to an increased development of larger collagen fibrils in early scar and a significant improvement in both scar failure strength (83-85% improvement at 6 weeks; p < 0.01) and scar creep elongation (33-48% less irrecoverable creep; p < 0.03) under loading. This is the first report that in vivo manipulation of collagen fibrillogenesis improves tissue function during repair processes with gene therapy. These findings not only suggest the potential use of this type of approach to improve the healing of various soft tissues (skin, ligament, tendon, and so on) but also support the use of such methods to better understand specific structure-function relationships in scars.

The gravity sag view: a simple radiographic technique to show posterior laxity of the knee.

We introduce a simple radiographic technique of taking a "gravity sag view" to show sagittal laxity secondary to posterior cruciate ligament injury. Side-to-side differences of the tibia-femur step-off measured with these radiographs have proved to be useful parameters for evaluating posterior laxity. This radiographic technique is recommended instead of routine lateral radiographs taken with the knee kept recumbent.

Preoperative anterior knee laxity did not influence postoperative stability restored by anterior cruciate ligament reconstruction.

Eighty-six chronic anterior cruciate ligament (ACL)-injured patients were quantitatively measured for anterior knee stability preoperatively and at 2 years or later (mean, 30 months) postoperatively to examine the influence of preoperative knee laxity on the postoperative knee stability restored by the ACL reconstruction using multiplied hamstring tendon graft. The patients were divided into 3 groups according to the preoperative injured minus normal anterior laxity difference (AL-D) (group I [n = 27] <5 mm, group II [n = 48] 5 to 9 mm, group III [n = 11] >10 mm). The 3 groups were comparable in gender, age, meniscal status, graft excursion measured during operation, time from injury to operation, and activity level. The postoperative AL-D in group I was 0.8 +/- 1. 7 mm, that in group II was 1.1 +/- 1.6 mm, and in group III was 1.5 +/- 1.4 mm. There were no significant statistical differences among these 3 groups. With our surgical technique including postoperative rehabilitation, patients with severe instability could be treated successfully without needing any additional procedures such as extra-articular augmentation or specially designed postoperative rehabilitation programs.

Reconstruction of the lateral ligaments of the ankle using solvent-dried and gamma-irradiated allogeneic fascia lata.

We have described a method of anatomical reconstruction of the lateral ligaments of the ankles with instability using allogeneic fascia lata dried with solvents and sterilised with gamma irradiation. Twenty ankles of 20 patients were assessed objectively and subjectively after a mean follow-up of 4.2 years (3.1 to 10). The result was excellent in 12 (60%), good in seven (35%) and fair in one (5%); none had a poor result. Stress radiography showed that the angle of talar tilt improved from 12.3+/-4.2 degrees (mean +/- SD) to 5.9+/-3.0 degrees and that the anterior drawer distance decreased from 9.2+/-3.9 mm to 4.4+/-2.5 mm. Neither infection nor limitation of movement occurred after operation. Fascia lata allografts provide a good alternative to autogenous grafts such as the peroneus brevis tendon.

Comparison of eccentric and concentric screw placement for hamstring graft fixation in the tibial tunnel.

Interference screw fixation of four-strand hamstring grafts for ACL reconstruction has recently been introduced. By this method, the interference screw is placed in the tibial and femoral tunnels eccentric (adjacent) to the bundled limbs of the graft. In order to maximize the graft to tunnel contact to promote biological fixation, it is proposed to place the screw concentrically in the tunnel, in the middle of the four limbs of the graft, pressing each limb of the graft into the tunnel wall. This would be difficult to do in the proximal, folded end of the four limb graft situated in the femoral tunnel but can be done easily in the tibial tunnel. The purpose of this study was to evaluate the effect of screw placement on the stiffness, yield load, and ultimate load of hamstring graft fixation in the tibial tunnel. Five pairs of human knees were used for the study. Pull out tests were performed using an MTS system, pulling along the axis of the tibial tunnel. Tibial fixation stiffness was greater using concentric screw placement (P < 0.05) although there was no statistical difference in yield load, slippage, or ultimate load.

Chondral injury associated with acute isolated posterior cruciate ligament injury.

SUMMARY: To evaluate associated cartilaginous damage with acute isolated posterior cruciate ligament (PCL) injury without other concomitant ligamentous injury, arthroscopic evaluations were performed on 61 consecutive patients. Meniscal tear was found in 17 cases (28%). Of these, 3 had medial meniscal tear, 11 had lateral meniscal tear, and 3 had both medial and lateral meniscal tears. Longitudinal tears of anterior segment in lateral menisci were the most common (10 cases). Thirty-two patients (52%) had articular cartilage injury. Of these, 7 had damage greater than one half of the thickness of the articular cartilage, and 3 had erosion that extended to the subchondral bone. The most frequently injured location was the medial femoral condyle (19 cases, 31%). Significant cartilaginous injury could be combined in acute isolated PCL injury. Therefore, it is unreasonable to manage every acute isolated PCL-injured knee using a single treatment modality. Concomitant meniscal and articular cartilaginous lesions should be evaluated when treatment for acute PCL injury is planned.

Device for magneto-optic signal detection with a small crystal prism.

A device made of a birefringent crystal for signal detection of magneto-optic (MO) disks is presented. The light beam from a MO disk is separated into two orthogonally polarized components at the surface of a birefringent prism. After these two components are reflected by the top and the bottom surfaces of the prism inside, at the detector they become sufficiently separated from each other for discrete detection, even though the prism is small. A method for calculating the light intensities and the positions of focused beams in a birefringent prism and the results of a fundamental experiment are presented.

Direct in vivo gene transfer to healing rat patellar ligament by intra-arterial delivery of haemagglutinating virus of Japan liposomes.

BACKGROUND: Manipulation of ligament healing has been a major focus of orthopaedic research. In recent years, gene transfer to healing ligament appears to be a feasible method for manipulating the healing process. In this study, we investigated the feasibility of gene transfer to healing rat patellar ligament by intra-arterial delivery. METHODS: An attempt was made to transfer a reporter gene (Escherichia coli, beta-galactosidase gene) to healing rat patellar ligament using the haemagglutinating virus of Japan (HVJ) liposome-mediated gene transfer method. Three days after cutting the patellar tendons of 25 14-week-old male Wistar rats, HVJ-liposome complexes containing beta-galactosidase (beta-gal) cDNA were injected into the femoral artery of 15 Wistar rats as the experimental group. HVJ liposomes without DNA were injected into the femoral artery of 10 Wistar rats as the control group. Three rats from the experimental group and two control rats were killed 3, 7, 14, 28 and 56 days after the injection. RESULTS: After X-gal staining, the rate of transfection in the experimental group (mean +/- SEM) was found to be 12.1% +/- 0.590%, 8.7% +/- 0.217%, 10.2% +/- 0.227%, 3.2% +/- 0.247% and 0.7% +/- 0.060% at post-injection days 3, 7, 14, 28 and 56 respectively. In control sections the number of blue-stained cells were very few at any point. CONCLUSION: We succeeded in introducing a reporter gene into healing rat patellar ligament by infra-arterial delivery of HVJ-liposome complexes. This method appears to have the potential to be applicable for soft-tissue healing studies and also healing studies of other tissues and organs.

Osteochondritis dissecans of the lateral femoral condyle of the knee joint.

Differences in the features of osteochondritis dissecans (OCD) affecting the lateral and medial femoral condyles were investigated in 13 patients (14 knees) treated from 1991 to 1994. OCD affected the lateral femoral condyle in 6 knees (lateral group) and the medial condyle in 8 knees (medial group). The lateral group was younger (mean age, 14 v. 20 years). The radiological stage (Brückl) of the lateral group was stage 2 in 3 knees and stage 3 in 3. The lateral menisci were all discoid and the condylar articular surface of the lesions was normal in two knees, softened in 3 and detached in 1. The medial group comprised 1 knee in stage 2, 1 in stage 3, 1 in stage 4, and 5 in stage 5. The OCD lesion showed softening in 2 knees and detachment in 6. Repetitive abnormal stress on weaker osteochondral structures in the growing period produced by a discoid meniscus during growth may cause OCD of the lateral femoral condyle.

Cross-sectional area measurement of the semitendinosus tendon for anterior cruciate ligament reconstruction.

We measured the cross-sectional area (CSA) of the semitendinosus tendon (SMT) in 79 anterior cruciate ligament (ACL)-injured patients using magnetic resonance imaging (MRI) to scrutinize their appropriateness for ACL grafts. Measurements of the CSAs of the SMT with MRI were closely correlated with intraoperative direct measurement (y = 0.697). The mean CSAs of the SMT measured with MRI ranged from 6.3 to 15.0 mm2 with a mean of 10.1+/-2.1 mm2. The CSA of the SMT measured with MRI proved to be a useful indicator to determine preoperatively whether the SMT graft would be of adequate dimensions (7 mm or more in diameter, 60 mm or more in length) for ACL reconstruction. If the CSA of the SMT was more than 11 mm2, a sufficiently thick and long graft could be prepared with a tripled or quadrupled SMT in 89% of cases. We conclude that tissue CSA measurements using MRI could potentially be implemented as a useful tool for determining the most appropriate donor autograft tissue preoperatively, thus minimizing harvest-site morbidity.