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Biomedical subjects

K Herrlin

Publications and source records attributed to K Herrlin.

50 records · Page 3Linked to original sources

Incidence and stability of trochanteric femoral fractures.

Sex, age and stability were recorded in 376 cases of trochanteric femoral fractures. In 168 cases the age and sex specific incidence was determined. When comparing our results with those in previous studies from the same region there was no increase that could not be related to age. This is in contrast to other reports from Scandinavia where investigators have found an increase in fracture incidence that could not be explained by the increasing number of old people. We, as others, have found a high proportion of unstable fractures. The unstable fractures did not occur more frequently in the oldest age groups.

Adult↗

Computed tomography in suspected osteoid osteomas of tubular bones.

Six cases of suspected osteoid osteoma of tubular bones were evaluated by computed tomography (CT). In all cases a radiolucent nidus was clearly demonstrated. In two cases a radiodense center of the nidus was visualized. It is suggested that CT may replace conventional tomography in the evaluation of these lesions. Due to its ability to locate the lesion in the transverse plane, CT is superior for the exact planning of surgery to avoid unnecessary large or misdirected resections. Adequate window settings are essential in the evaluation of these lesions.

Adolescent↗

Computed tomography of intramuscular myxoma.

Computed tomography (CT) was performed in seven patients with intramuscular myxoma. All lesions were well demarcated, of homogeneous appearance and attenuation values ranging from 10 to 60 (HU). The tumor size, as estimated at CT, correlated well with the size of the surgical specimen, which is in contrast to the findings in some high grade malignant sarcomas.

Adult↗

Comparison of computed tomography and angiography in the evaluation of soft tissue tumors of the extremities.

CT and angiography were performed in 21 patients with soft tissue tumors of the extremities (18 malignant and 3 benign) and the results were compared with the surgical and histopathologic findings. The tumor size was correctly evaluated at CT in 15 of 21 cases and at angiography in 17 of 21 cases. The main reason for overestimation of longitudinal tumor extent seems to be edema surrounding the poles of high grade malignant neoplasms. CT was superior to angiography in demonstrating the intra- or extramuscular tumor location. If only factors important for the surgical planning are considered, angiography yielded such information in 8 cases while CT was of critical value in the preoperative evaluation of 14 patients. It is concluded that CT should precede angiography in the examination of soft tissue tumors of the extremities. Angiography may be superior to CT in demonstrating vascular anatomy in relation to tumors of the medial thigh. With other tumor locations, angiography should be reserved for those lesions where vascular relationships are not adequately demonstrated at CT.

Adult↗

Anteversion measurements in trochanteric fractures of the femur.

The anteversion of the femur was measured in trochanteric fractures operated upon with nail-plate or Ender osteosynthesis, and the results were compared with a normal material. A significant reduction in anteversion was found in the cases with Ender osteosynthesis as a possible explanation for the outward rotation of the operated limb commonly observed in these patients. No difference in anteversion was found between cases operated upon with conventional Ender technique, i.e. without anteversion of the nails, and those operated upon with a modified technique where the nails had been anteverted if considered appropriate at the operation.

Biomechanical Phenomena↗

Chronic progressive osteoblastic osteomyelitis: a new approach to treatment.

The clinical, histologic and radiographic picture in 16 cases in 15 patients with nonfistulating chronic progressive osteoblastic osteomyelitis of a long tubular bone which started in childhood is presented. All patients had severe pain at rest or weightbearing. Histology showed an increase of active osteoblasts. Low virulent bacteria were found in one-fourth of the patients. To reduce the osteoblastic activity, nonsteroidal antiinflammatory treatment was combined with surgical and antibiotic treatment. Eleven patients were pain-free at follow-up (average 47 months), 3 had reduced pain, and 1 patient did not respond to treatment.

Adolescent↗

Space orientation of total hip prosthesis. A method for three-dimensional determination.

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.

Arthrography↗

Trochanteric fractures. Classification and mechanical stability in McLaughlin, Ender and Richard osteosynthesis.

Four hundred and thirty trochanteric fractures operated upon with McLaughlin, Ender or Richard's osteosynthesis were divided into 6 different types based on their radiographic appearance before and immediately after reposition with special reference to the medial cortical support. A significant correlation was found between the fracture type and subsequent mechanical complications where types 1 and 2 gave less, and types 4 and 5 more complications. A comparison of the various osteosyntheses showed that Richard's had significantly fewer complications than either the Ender or McLaughlin types. For Richard's osteosynthesis alone no correlation to fracture type could be made because of the small number of complications in this group.

Bone Nails↗

Digital radiography of the spine, large bones and joints using stimulable phosphor. Early clinical experience.

The value of digital radiography in musculoskeletal disorders was investigated by assessing its ability to depict anatomic structures and common radiologic features as compared with the conventional film-screen combination. The digital image that was frequency modified was superior to conventional films in delineating soft tissue structures and for areas with large attenuation differences. The conventional film-screen system was superior in depicting small anatomic structures and in identifying the zone close to prostheses. This was explained by the high spatial resolution of the conventional film system and the disturbing halo effect around the prosthesis seen with digital images. The halo effect is an overshoot caused by the unsharp masking operator, which was in this series not changed for individual examinations. The exposure (radiation dose) could be reduced to 50 per cent using the digital system, without any loss of information.

Arthrography↗

Comparison of two- and three-dimensional methods for assessment of orientation of the total hip prosthesis.

A comparison of two- and three-dimensional methods for the determination of the orientation of total hip prostheses was made in a group of 57 patients. The acetabular inclination and the collum-diaphyseal angle measured on a.p. projections (2-D) were adequate in most cases for assessing how vertically the prosthetic component was inserted, but in individual cases with a high degree of version these measurements could be misleading. Anteversion measured in the transverse plane (2-D) was more sensitive to errors than planar anteversion measured as a rotation around the longest diameter of the ellipsoid projection of the acetabular opening, but it gave a rough estimate of the relation of the prosthetic components. Determination of the spatial (3-D) orientation of the components provides a precise estimate of the component relations.

Acetabulum↗

Femoral anteversion and restricted range of motion in total hip prostheses.

Impingement of the neck of the stem on to the rim of the socket may cause dislocation of the total hip prosthesis. The role of femoral anteversion in the occurrence of such impingement was analyzed in a clinical material of total hip prostheses with and without dislocation. A low femoral anteversion was linked to a clinically relevant reduction of the range of motion due to impingement and dominated in the group with dislocations. Impingement is minimized by inserting the femoral component in 10 degrees to 20 degrees of anteversion.

Aged↗

Range of motion caused by design of the total hip prosthesis.

In a clinical material of total hip prostheses, a study was performed of the range of femoral motion until impingement occurred between the neck of the femoral stem and the rim of the acetabular socket. The results were compared with the physiologic range of motion, and the clinically relevant motion restriction was measured. Restriction was most common in flexion. There was a correlation between the prosthetic design and the restriction due to impingement.

Aged↗

Position, orientation and component interaction in dislocation of the total hip prosthesis.

The position, orientation in space and interaction of prosthetic components was determined in 15 patients with known episodes of dislocation after total hip replacement. The same calculations were performed in a reference group of 44 patients without dislocation. In the group with dislocations, there was a significantly decreased femoral anteversion, and a decreased femoral flexion permitted by the prosthetic components. There were no further significant differences of clinical relevance between the groups concerning all other examined parameters of component position, orientation and interaction. It is concluded that the decreased range of flexion, caused by impingement of the prosthetic components with ensuing leverage effect is one cause of dislocation.

Aged↗