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Biomedical subjects

A Lebech

Publications and source records attributed to A Lebech.

6 recordsLinked to original sources
PubMed1999

Preoperative bone mineral density of the proximal tibia and migration of the tibial component after uncemented total knee arthroplasty.

Twenty-two patients with primary osteoarthrosis of the knee all operated on with insertion of an uncemented total knee arthroplasty had a preoperative measurement of bone mineral density (BMD) in the coronal plane of the proximal tibia performed by dual-photon absorptiometry. Postoperatively and with follow-up after 6 weeks (n = 21), 1 year (n = 22), and 3 years (n = 19), radiographs suitable for radiostereometric analysis of the tibial component migration were obtained. One year postoperatively, stress examinations were performed with the aim of measuring inducible displacement of the tibial component. Most of the migration, expressed as maximal total point motion (MTPM), occurred during the first year with an average migration of approximately 1 mm. Regression analysis showed a positive relation between BMD and MTPM after 6 weeks (P = .03, r = .47), 1 year (P = .0005, r = .68), and 3 years (P = .02, r = .54). Inducible displacement did not reveal any significant relation to BMD. MTPM between 1 and 3 years, which is the clinically most important parameter with respect to later loosening of the tibial component, showed a negative relation to BMD (P = .04, r = -.47). Thus, tibial components of knees with preoperative high tibial BMD showed less continuous migration.

Aged↗
PubMed1997

Roentgen stereophotogrammetric analysis using computer-based image-analysis.

The two-dimensional position of markers in radiographs for Roentgen Stereophotogrammetric Analysis (RSA) is usually determined using a measuring table. The purpose of this study was to evaluate the reproducibility and the accuracy of a new RSA system using digitized radiographs and image-processing algorithms to determine the marker position in the radiographs. Four double-RSA examinations of a phantom and 18 RSA examinations from six patients included in different RSA-studies of knee prostheses were used to test the reproducibility and the accuracy of the system. The radiographs were scanned at 600 dpi resolution and 256 gray levels. The center of each of the tantalum-markers in the radiographs was calculated by the computer program from the contour of the marker with the use of an edge-detection software algorithm after the marker was identified on a PC monitor. The study showed that computer-based image analysis can be used in RSA-examinations. The advantages of using image-processing software in RSA are that the marker positions are determined in an objective manner, and that there is no need for a systematic manual identification of all the markers on the radiograph before the actual measurement.

Arthrography↗
PubMed1991

Hematomas and subcutaneous suture techniques in total hip replacement. An ultrasound study.

Thirty-five patients undergoing total hip replacement due to primary arthrosis were randomized into two groups. In one group each subcutaneous suture included a stitch in the fascia; in the other group the fascia was not included in the suture. Ultrasonography examination showed no significant difference in the number of subcutaneous hematomas in each group. Nine subcutaneous and nine deep hematomas were diagnosed by ultrasound in 15 patients. Three patients had a clinical diagnosis of hematoma and in only one of these did ultrasonography support the diagnosis. It appears that the clinical diagnosis of hematomas, even subcutaneous hematomas, is unreliable. Careful hemostasis is recommended.

Aged↗
PubMed1991

An unusual type of fracture in the upper sacrum.

An unusual type of indirect isolated fracture of the upper sacrum is presented. The upper sacrum was markedly comminuted and nondisplaced relative to the lower fragment. There was a neurologic deficit present. On the basis of a review of the literature, a previous classification system and the actual fracture mechanism, this fracture is classified as a special type; type 4, or the neutral position fracture.

Female↗
PubMed1990

[Hypertension following blunt kidney injury].

The incidence of hypertension after blunt renal injury is reviewed on the basis of the available literature in English and Danish from 1934 to the present day. The selected literature fulfills defined requirements as regards quality. Hypertension develops one to two days after the trauma and this remits spontaneously after an average of 29 (7-50) days. The reason for this is a perirenal haematoma which produces ischaemic renal tissue by compression after which the haematoma is resorbed. This is demonstrated by urography and investigation of the renin-angiotensin system. The frequency is stated to be 6.7% in an isolated investigation but this must be regarded with reservation. A considerably longer period after the trauma, permanent hypertension develops. This is due to permanent pathological changes which produce ischaemic renal tissue by compression or stenosing of the lumina of the renal arteries. The frequency of this type of hypertension is so low that it cannot be estimated on the basis of the follow-up examinations carried out. These show a frequency of hypertension of between 2.3 and 3.8% which may be explained by the development of spontaneous hypertension. A definite relationship between permanent hypertension and blunt renal injury has only been found in 28 case reports.

Adolescent↗