SEARCH · PubMed Health
Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.
Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.
A three-dimensional method to analyse the kinematics of the spine has been applied to four pigs with experimentally provoked scoliosis. The advantages and limitations of the method are discussed and some interesting facts concerning the provoked curves are emphasized.
Five pigs operated upon by posterior spinal fusion were examined by a roentgen stereophotogrammetric method during provoked motion. The healing process leading to marked rigidity within the spine was followed in two of the pigs. Varying degrees of stability in the fused area were achieved in the five animals. Movements were detected, not only when the fusions were not healed, but also in two cases of incomplete bony union between two operated segments.
Three cases operated upon with posterolateral fusion in the lumbosacral spine have been subjected to a kinematic postoperative analysis with the aid of a roentgen stereophotogrammetric method. The primarily diseased intervals became comparatively rigid in spite of significant residual mobility, in two of the patients, not until 174 days postoperatively. Three levels of operation displayed unrestricted residual mobility.
Three cases with idiopathic, structural scoliosis were examined postoperatively with a roentgen stereophotogrammetric method. Curvatures developed in both the frontal and sagittal planes. Axial rotation also occurred. In addition, residual mobility was demonstrated and quantified one year postoperatively.
Two different methods for determination of leg growth, the tetracycline method and roentgen stereophotogrammetry, were applied simultaneously in 41 young rabbits and compared 1 and 2, and 21 and 22 days after insertion of pins or balls of tantalum as markers. The tetracycline method gave slightly higher values than the other method, the difference varying between 77 and 6 micrometer/d on the first 2 days after marker insertion and between 32 and 1 micrometer/d after 3 weeks. When ball markers were used, agreement between the two methods was obtained 3 weeks after insertion. The difference between the methods used is due to that the two methods did not measure growth in precisely identical regions.
Model experiments and tests on 2 patients were performed to probe the feasibility of roentgen stereophotogrammetry for evaluating variations in shape and volume of the liver. The surface of the object was marked with indicators, and the three-dimensional marker coordinates were determined. The model experiments demonstrate a good correlation between true volume and the volumes defined by the indicators, and also demonstrate the possibility of localizing an expansivity. The variability of the volume of a polyhedron defined by 15 liver indicators with stage of breathing is discussed.
Using a roentgen stereophotogrammetric method, the three-dimensional movements in the sacroiliac joints were quantified in 4 patients. To provoke motion of the sacrum, changes between body positions and a test with manual pressure were used. In tests with symmetric forces on the sacrum, it in most cases rotated mainly about a transverse axis and at most approximately 2 degrees. The axis of rotation passed through the iliac bones mainly in the lower part of the iliac tuberosity. The rotations between the iliac bones and the sacrum about any of the three main axes were determined with a precision in the mean of 0.2 degrees. The distance between the two superior posterior iliac spines varied at most 0.4 mm between seven different body positions.
The spatial location of points in an object can be determined by roentgen stereophotogrammetry. A technique of high accuracy was applied in a determination of the daily skeletal growth of young rabbits. The tibia was labelled with tantalum markers on each side of the growth zones, and the increasing distance between these markers due to longitudinal bone growth was measured. Three different types of markers were tested, and the methodologic error was estimated. It varied between 30 and 43 micrometer for one growth interval, depending on the type of marker used. The method has clinical implications currently under investigation.
Localization of motion axes within joints and junctures in living humans has been carried out by means of roentgen stereophotogrammetry. Another technique is presented here, in which the localization of the axis is carried out by means of tomography. The field of application for this technique has been examined in a series of phantom experiments. It may be employed in certain situations where roentgen stereophotogrammetry is not useful. No other equipment is needed than a pluridirectional tomograph and conventional dark-room facilities.
A photogrammetric method developed for measurement of femoral neck anteversion was used to evaluate the torsion in 28 femoral fractures sustained in childhood and treated conservatively. Spontaneous correction of the initial torsion of 10 degrees to 30 degrees to less than 10 degrees was the rule in a growing femoral bone within 5 to 10 years after trauma.
The principles for a system of roentgen stereophotogrammetric analysis for experimental and clinical applications are presented. Only the positions of implanted reference markers in the investigated object are measured. Tantalum balls, 0.5 or 0.8 mm in diameter, are used as reference markers. Standard roentgen equipment, permitting simultaneous exposure from two roentgen tubes, is employed. The calibration equipment, a glass calibration cage containing radiopaque markers, introduces a rectangular laboratory coordinate system in the roentgen investigation. The calibration of the calibration equipment itself and the obtained methodologic accuracy in determining distances, volumes and movement parameters is described for various film/screen and marker combinations.
A method for in vivo determination of orientation and relation in space of components of total hip prosthesis is described. The method allows for determination of the orientation of the prosthetic components in well defined anatomic planes of the body. Furthermore the range of free motion from neutral position to the point of contact between the edge of the acetabular opening and the neck of the femoral component can be determined in various directions. To assess the accuracy of the calculations a phantom prosthesis was studied in nine different positions and the measurements of the space oriented parameters according to the present method correlated to measurements of the same parameters according to Selvik's stereophotogrammetric method. Good correlation was found. The role of prosthetic malpositioning and component interaction evaluated with the present method in the development of prosthetic loosening and displacement is discussed.
BACKGROUND: Injury of the anterior cruciate ligament changes the kinematics of the knee joint. In studies of cadaveric knees, investigators have examined the effect of anterior cruciate ligament reconstruction on knee kinematics, but the effect on dynamic knee motion is not known. HYPOTHESIS: Reconstruction of the anterior cruciate ligament restores knee kinematics to normal. STUDY DESIGN: Prospective cohort study. METHODS: Nine patients were examined preoperatively and 1 year after reconstruction. Continuous radiostereometric exposures were performed at a speed of two to four exposures per second while the patients ascended an 8-cm high platform. Tibial rotation and tibial and femoral translation were measured with radiostereometric analysis. RESULTS: Tibial rotation and tibial and femoral translation were not significantly different after anterior cruciate ligament reconstruction compared with preoperative measurements. A radiostereometric evaluation of anterior knee laxity revealed restoration to within 1 mm of that on the uninjured side. Further evaluation of knee function using the Lysholm score, the Tegner activity level score, the International Knee Documentation Committee evaluation system score, and measurements of laxity using the KT-1000 arthrometer revealed significant improvements after reconstruction. CONCLUSION: Kinematics of the anterior cruciate ligament injured knee did not change significantly after ligament reconstruction, but the functional results were satisfactory and knee laxity was diminished.
The rotatory stability of the knee was investigated in 20 patients with a previous tear of the ACL. The three-dimensional movements of the tibia during the testing procedure were registered using roentgen stereophotogrammetric analysis. Changes of the tibial movements between an intermediate, an anterior, or a posterior tibial position were registered using tibial tractions in combination with a simultaneous external or internal rotatory torque. At 20 degrees of flexion the internal rotatory laxity was increased on the injured side. The external rotatory laxity did not significantly differ between the two sides. With anterior traction, the internal rotatory laxity increased on both the injured and the normal sides and became almost equal. The external rotatory laxity manifested a decrease which was most pronounced on the injured side. With posterior traction, the rotatory laxities decreased and did not significantly differ between the two sides. Analysis of the simultaneously occurring translations of the tibial plateau disclosed abnormal displacements of both the medial and the lateral tibial condyles on the injured side.
The mechanical support provided by a semirigid ankle orthosis was tested in 14 ankles with symptoms of chronic lateral instability by use of stereophotogrammetric analysis. Talar and calcaneal rotations were measured with and without the Strong ankle orthosis during manual adduction test and adduction test with a predetermined torque (5 N-m). Significant reduction of talar and calcaneal plantar flexion, internal rotation, and varus angulation was noted when the orthosis was applied. The results of this study suggest that the semirigid orthosis may provide enough external support to prevent ankle sprains and to protect ligament reconstructions.
Nine fresh-frozen, human cadaveric shoulders were elevated in the scapular plane in two different humeral rotations by applying forces along action lines of rotator cuff and deltoid muscles. Stereophotogrammetry determined possible regions of subacromial contact using a proximity criterion; radiographs measured acromiohumeral interval and position of greater tuberosity. Contact starts at the anterolateral edge of the acromion at 0 degrees of elevation; it shifts medially with arm elevation. On the humeral surface, contact shifts from proximal to distal on the supraspinatus tendon with arm elevation. When external rotation is decreased, distal and posterior shift in contact is noted. Acromial undersurface and rotator cuff tendons are in closest proximity between 60 degrees and 120 degrees of elevation; contact was consistently more pronounced for Type III acromions. Mean acromiohumeral interval was 11.1 mm at 0 degrees of elevation and decreased to 5.7 mm at 90 degrees, when greater tuberosity was closest to the acromion. Radiographs show bone-to-bone relationship; stereophotogrammetry assesses contact on soft tissues of the subacromial space. Contact centers on the supraspinatus insertion, suggesting altered excursion of the greater tuberosity may initially damage this rotator cuff region. Conditions limiting external rotation or elevation may also increase rotator cuff compression. Marked increase in contact with Type III acromions supports the role of anterior acromioplasty when clinically indicated, usually in older patients with primary impingement.
Explore the source record for details and available documents.
In six cadaver specimens the mobility of the proximal fibula in relation to the tibia was investigated during plantar/dorsiflexion of the ankle, using Roentgen Stereophotogrammetric Analysis (RSA). The role of the ankle joint, and of the calcaneofibular and talofibular ligaments was also evaluated. The greatest movements were observed along the mediolateral and anterior-posterior axes, resulting in an anterolateral displacement of the fibula head during dorsiflexion and in a postero-medial displacement during plantarflexion. This study demonstrated a limited mobility of the proximal tibiofibular joint. Moreover, the ligament cutting and the presence of constraints in the ankle region did not show any effect on the fibular movement.