BACKGROUND:A method to describe pelvic rotations between pairs of standard sequential pelvic anteroposterior radiographs based on a pelvic phantom is described in a former study.PURPOSE:To expand this method into clinical use based on clinical data.MATERIAL AND METHODS:Teardrop distances were measured on 262 pelvic radiographs from 46 patients in a clinical material using a computer program designed to perform measurements on digital radiographs. Anthropometric data recorded from 141 pelvises in an anatomical collection were employed in a computer program designed to simulate radiographs of virtual objects. Virtual rotations of the pelvises were carried out with 4653 virtual radiographs obtained. Virtual radiographic measures were analyzed.RESULTS:A statistically significant difference of 8 mm between mean teardrop distance in females (120 mm) and males (112 mm) was found in the clinical material. A set of formulas describing the relations between differences of two rotation ratios and pelvic rotations were derived. Four simple regression analyses were carried out with the use of virtual measures. Adjusted teardrop distances were implemented.CONCLUSION:A clinical method to describe pelvic rotations using standard pelvic radiographs was developed.

Background: Radiographic measurements made on standard pelvic radiographs are commonly used in studying conditions related to the hip joints. Effects caused by variations in pelvic orientation may be a source of error in comparing measurements between sequential radiographs. Purpose: To define and characterize parameters able to measure rotational differences separately around two axes and altered radiographic focusing along two axes when sequential standard anteroposterior (AP) pelvic radiographs are compared. Material and Methods: A pelvic phantom was constructed based on direct three-dimensional measurements of five defined landmarks in a pelvic model. Two ratios, the vertical and transversal rotation ratios, were defined using radiographs of the phantom. The phantom was radiographed in 33 different orientations and with 16 different radiographic focuses using a specially constructed tilt table. On each radiograph, measurements were made and the two rotation ratios were calculated using a measurement program. Results: Linear correlations between pelvic rotations around one axis and the corresponding rotation ratio were found with almost no influence of simultaneous rotation around the other axis. Also, linear correlations were found between altered radiographic focusing along one axis and the non-corresponding rotation ratio. Conclusion: Rotational differences around two axes or altered radiographic focusing along two axes can be measured independently. Effects caused by rotations cannot be distinguished from effects caused by altered radiographic focusing.

Background: The rotation ratios method describes rotations between pairs of sequential pelvic radiographs. The method seems promising but has not been validated. Purpose: To validate the accuracy of the rotation ratios method.Material and Methods: Known pelvic rotations between 165 radiographs obtained from five skeletal pelvises in an experimental material were compared with the corresponding calculated rotations to describe the accuracy of the method. The results from a clinical material of 262 pelvic radiographs from 46 patients defined the ranges of rotational differences compared. Repeated analyses, both on the experimental and the clinical material, were performed using the selected reference points to describe the robustness and the repeatability of the method.Results: The reference points were easy to identify and barely influenced by pelvic rotations. The mean differences between calculated and real pelvic rotations were 0.0 degrees (SD 0.6) for vertical rotations and 0.1 degrees (SD 0.7) for transversal rotations in the experimental material. The intra- and interobserver repeatability of the method was good.Conclusion: The accuracy of the method was reasonably high, and the method may prove to be clinically useful.

Femoral anteversion (AV) was determined by ultrasound in 40 adolescent and adult patients with rotational disorders of the femur, and the results were compared with AV measurements by biplanar roentgenography. With the patients supine, their knees flexed 90°, and their lower legs strapped in the vertical position, one scan only of the proximal femur was needed to measure the anteversion by ultrasound. The transducer was tilted until the desired measuring line appeared horizontal on the monitor screen. The angle of tilt of the transducer, which represented the AV angle, was measured with an attached clinometer. The correlation between ultrasound and roentgenographic AV angles was high, indicating that reliable results were obtained by ultrasound. The preferred reference line was the head-trochanter tangent, which is recommended for clinical use. Consistently greater AV values were measured by ultrasound than by roentgenography. Thus, 10" should be subtracted from the ultrasound values in order to obtain the real AV angles. One of the benefits of ultrasound is the elimination of radiation hazards to the patients. Ultrasound is recommended as a screening technique for patients with rotational disorders of the femur.

Because there is no consensus with regard to the efficiency of the Frejka pillow in the treatment of hip joint dysplasia in newborns, the aim of the present study was to evaluate our results with this device. During the 3-year period 1988 to 1990, the Frejka pillow was used in 108 newborns with clinically unstable hips verified by ultrasonography. There were three treatment failures (2.8%). defined as infants who needed additional treatment with an abduction splint or hip-spica cast. Avascular necrosis of the femoral head occurred in one patient (0.9%). At an age of 3 years to 6 years, 85 of the children attended a follow-up examination. An intoeing gait was observed in 17% and slightly reduced hip mobility in 20% of the patients. Compared with normal children, the patients had somewhat lower coverage of the femoral head by radiography, indicated by a lower centre-edge angle and a higher migration percentage, but the coverage was within the normal range in all cases. The mean anteversion angle was larger than that of normal children but only three patients had abnormally high anteversion angles. In conclusion, the results with the Frejka pillow were good, with few treatment failures and complications, and it is the most simple abduction device for the parents to handle. More rigid devices like the von Rosen splint seem to involve a slightly lower failure rate, but a higher risk of avascular necrosis. Therefore, we recommend the Frejka pillow when treatment is started within a few days of birth.

In the first part of the study we examined the accuracy of femoral anteversion (AV) determined by fluoroscopy, simulating a method used in closed intramedullary femoral nailing. Twenty cadaveric femora were used. The condyles and posterior trochanteric area were resting on a horizontal table. The proximal femur was imaged using a C-arm image intensifier with horizontal X-ray beam at an angle of 30, 45, or 60° to the long axis of the femoral shaft. To evaluate the reliability of the measurements, the real AV angle was determined by radiography. A small difference (mean 2°) was found between the real AV angle and the angle between the horizontal plane and the central head–neck axis (NH angle) as displayed by the image intensifier. In a separate clinical study, the NH angle was assessed and used as a guide to intraoperative rotational reduction in ten patients with femoral shaft fracture using the aforementioned method. Follow-up examinations of the AV angle showed that rotational deformities of clinical significance were avoided.

Several extraarticular surgical procedures have been proposed to eliminate the anterolateral rotatory instability of an anterior cruciate-deficient knee. We examined the outcome in 52 patients with an extraarticular transposition of the lateral third of the patellar tendon to the lateral femoral condyle. The mean follow-up time was 9 years. The evaluation was based on the patients' subjective assessment, the Tegner activity level score, range of motion, Lysholm functional score, assessment of knee instability using manual testing as well as arthrometer measurements, and weight-bearing radiographs. At follow-up, 37 patients stated that they had good-to-excellent knee function. The mean Tegner score dropped from a preinjury level of 7 to 5.43 patients had a good-to-excellent Lysholm score. 20 patients had a positive Lachman sign of grade 2 or 3, and 23 patients had a side-to-side difference of more than 3 mm as measured by an arthrometer. 17 had a positive pivot shift sign. 12 patients had meniscal resections performed after the primary operation, and 27 had radiographic evidence of arthrosis. Although the outcome of this technique is equivalent to or better than results reported for other extraarticular procedures, the recurrence rate of symptomatic instability and the deterioration of subjective knee function are too high.

Anterior sacral meningocele is an uncommon and often occult disorder of clinical importance. The pelvic mass induces symptoms mainly because of its pressure on surrounding organs. Obstipation and urinary symptoms are common. In females, complications due to prolonged or obstructed labour and infections are serious and can be fatal. The radiological manifestation is quite typical. It is important to be aware of anterior sacral meningocele in order to reach the right diagnosis, and to suspect it when typical symptoms are present.

Only 5% of AS patients are B27 negative. We describe two cases of HLA-B27 negative AS in a father and a son who both developed clinical and radiological features characteristic of AS. Tissue typing for HLA-A,-B,-C was performed in all 1.degree family members except for the father who died in 1990. All family members possessed B40. HLA-B40 may contribute to an increased susceptibility for AS not only in B27 positive individuals but also in B27 negative cases.

Intrasacral meningeal cysts are relatively uncommon. They are usually asymptomatic, but because of their expansive character, radicular symptoms or functional disturbances in the urinary bladder or rectum can occur. It is of importance to recognize these cysts in order to give the patient the correct treatment and to avoid unnecessary examinations and operations. The diagnosis can be made by myelography, computer tomography or magnetic resonance imaging.

We measured the intercondylar notch of the femur in female handball players from radiographs of 20 players with previous unilateral anterior cruciate ligament injury, and 26 controls without injury, The groups were comparable regarding age, height, weight and level of performance.Intercondylar fossa radiographs were obtained in a posteroanterior axial position. The anterior opening of the intercondylar notch was narrower in the healthy knee of the injured group compared to the controls. There was an increased risk of anterior cruciate ligament injury associated with decreasing notch opening: female handball players with 17 mm or less anterior notch width were 6 times more susceptible to anterior cruciate ligament injury compared to players with wider notch width.

Cotugno described the clinical entity of sciatica in 1764. However, the association between sciatica and compression of lumbar nerve roots was not realized until the 1920s. Back surgery for herniated nucleus pulposus then became fashionable, and plain radiography and myelography enabled preoperative mapping. Recently other imaging techniques have emerged, such as computed tomography and magnetic resonance imaging. This has increased the knowledge of the etiology of lumbar root compressions, and invasive therapies for sciatica have become more diversified. It is easy to lose perspective among the available imaging procedures and therapeutic techniques. The aim of this paper is to present the current status from a historical point of view, with special emphasis on the most common imaging methods for the investigation of lumbosacral radiculopathies.

Femoral anteversion (AV) angles were determined by ultrasound and biplanar radiography in 63 children aged 3–11 years. With the patient supine, knees flexed 90°, and legs kept vertical, only one ultrasound scan of the proximal femur was needed. The anterior tangent of the femoral head and the greater trochanter was used as the reference line. The transducer was tilted until this tangent appeared horizontal on the monitor screen, and the angle of tilt, which represents the AV angle, was measured with an attached clinometer. There was a high correlation between ultrasound and radiographic results (r=0.71). However, the AV angles appeared an average of 5.5° larger by ultrasound. Thus, a correction factor of 5° should be subtracted from the angle measured by ultrasound to obtain the actual AV angle in children. Because ultrasound does not require ionizing radiation, and because reliable results are obtained, our technique is recommended for screening of children with rotational disorders of the femur.

Acetabular anteversion is an important parameter of the hip joint. It is measured at CT of the hip, as are the more recently introduced acetabular sector angles. These angles give information on the anterior and posterior support from the acetabulum to the femoral head. Some simple mathematical relationships between these angles are presented.

Atlantoaxial rotatory fixation is a disorder which must be considered in persistent torticollis. The disorder occurs mainly in children and young adults. The usual etiological factors are traumas or infections of the upper respiratory tract, but the onset may also be spontaneous. The pathogenesis of the fixation is poorly understood. We describe three patients with atlantoaxial rotatory fixation and demonstrate the usefulness of computerized tomography in the diagnosis of this condition. We recommend a posterior atlantoaxial fusion if conservative treatment fails to reduce the rotatory fixation.

Transpelvic CT was used to quantify the relationship between the acetabulum and proximal femur in 21 adult patients (33 hips) with congenital hip dysplasia (defined by a center edge angle of less than 20 degrees). The anterior and posterior acetabular sector angles (AASA and PASA) were measured, as well as the degree of acetabular and femoral anteversion. The results demonstrated deficient anterior acetabular support (i.e., decreased AASA) in approximately two-thirds of the dysplastic hips and reduced posterior support (i.e., decreased PASA) in one-third. The acetabular anteversion was normal. The femoral anteversion. however, was greater than normal in most hip. As important additional information is obtained by CT compared with conventional radiography, CT is recommended when operative procedures aimed at preventing or postponing osteoarthrosis are considered.