PubMed Health⌕ Search

Biomedical subjects

H J Hahne

Publications and source records attributed to H J Hahne.

At least 19 recordsLinked to original sources
PubMed2004

Comparable ultrasound measurements of ten anatomical specimens of infant hip joints by the methods of Graf and Terjesen.

PURPOSE: To define which sonographic section planes relative to the acetabular inlet plane will produce analyzable images with the methods of Graf and Terjesen. MATERIAL AND METHODS: Anatomical specimens of infant hip joints were investigated in a water bath using the methods of Graf and Terjesen. Acetabular position was varied in defined increments with respect to the ultrasound beam. The alpha angles and the femoral head coverage (FHC) were measured. RESULTS: To obtain images analyzable by the two methods, the ultrasound beam had to intersect with the acetabular inlet plane at defined angles. The acetabular notch had to be anteriorly rotated from the ultrasound beam plane by at least 20 degrees. Beam entry within a 50 degrees sector posterior to the perpendicular on the inlet plane resulted in analyzable images. The stepwise multiple linear regression analysis showed that alpha angles and FHC were much affected by the coronal-plane transducer tilt. CONCLUSION: The fact that caudal tilts of the transducer are associated with reduced alpha angles and FHC values should be kept in mind in clinical ultrasound investigations. It is recommended that the transducer should be put on the greater trochanter perpendicular to the transverse axis of the body.

Cadaver↗
PubMed2004

The dimensional accuracy of preparation of femoral cavity in cementless total hip arthroplasty.

OBJECTIVE: To observe the accuracy of femoral preparation and the position of the cementless prosthesis in femoral cavity, and to compare the results between the computer-assisted surgical group (CASPAR) and the conventional group. METHODS: Ten femoral components were implanted either manually or by CASPAR in cadaver femurs. The specimens were cut to 3 mm thick slices. Microradiograms of every slice were sent to a computer for analysis with special software (IDL). The gaps and the medullary cavities between component and bone, the direct bone contact area of the implant surface, the gap width and the percentage of gap and bone contact area were measured in every slice. RESULTS: In the proximal implant coated with HA of the CASPAR group, the average percentage of bone contact reached 93.2% (ranging from 87.6% to 99.7%); the average gap percentage was 2.9% (ranging from 0.3% to 7.8%); the maximum gap width was 0.81 mm and the average gap width was only 0.20 mm. While in the conventional group, the average percentage of bone contact reached 60.1% (ranging from 49.2% to 70.4%); the average gap percentage was 32.8% (ranging from 25.1% to 39.9%); the maximum gap width was 2.97 mm and the average gap width was only 0.77 mm. The average gap around the implant in the CASPAR group was only 9% of that in the manual group; the maximum and average gap widths were only about 26% of those in the manual group. On the other hand, the CASPAR group showed 33% tighter bone contact than the manual group. CONCLUSION: With the use of robotics-assisted system, significant progress can be achieved for femoral preparation in total hip arthroplasty.

Arthroplasty, Replacement, Hip↗
PubMed2003

Survival analysis of hips treated with flexion osteotomy for femoral head necrosis.

The treatment of osteonecrosis of the femoral head (FHN) is controversial. It mainly occurs in young patients in whom total hip replacement is best avoided because of an increased risk of revision. The objective of this long-term follow-up study was to evaluate the outcome of intertrochanteric flexion osteotomy as a hip joint preserving operation for FHN. Over a 19-year period we carried out 70 intertrochanteric flexion osteotomies for FHN in 64 patients. The mean follow-up was 10.4 years (3.0 to 20.3). The overall mean Harris hip score increased from 51 points preoperatively to 71 points postoperatively. Six patients (9%) developed early postoperative complications. A total of 19 hips (27%) underwent total hip arthroplasty at a mean of 8.7 years after osteotomy. The five-year survival rate was 90%. Survival rates of hips in Ficat stage 2 were higher than those in stages 3 or 4. Hips with a preoperative necrotic angle of <200 degrees had a better survival probability than those with a necrotic angle >200 degrees. Our findings suggest that flexion osteotomy is a safe and effective procedure in Ficat stage 2 and 3 FHN, preferably with a necrotic angle of <200 degrees.

Adolescent↗
PubMed1999

Sonographic hip screening and early management of developmental dysplasia of the hip.

The reliability of Graf's technique in diagnosing developmental dysplasia of the hip (DDH) is investigated in this report. In a prospective study, 6,548 neonates were examined clinically and sonographically; 470 children were reexamined at least once. Sonographic alpha angles and radiographic acetabular index (AI) angles were followed up and compared. Results were as follows: 84.6% of the hips were mature; 14.3% were physiologically immature; 1.1% were dysplastic. Of the sonographically dysplastic hips, 63% were clinically normal. Neonatal sonographic hip status was affected by family history, breech delivery, birth weight, and gestational age. At follow-up, none of the primarily mature hips had worsened. Of the type IIa hips, 89% matured spontaneously, and 11% needed abduction. The 68 dysplastic hips had matured after a maximum of 80 days' abduction, with normal alpha and AI angles by the end of treatment. At 1 year, the pitch had deteriorated again in six children. Graf's sonographic technique reliably diagnoses infantile DDH. Regular orthopedic checkups are needed to detect secondary deterioration of dysplastic hips.

Birth Weight↗
PubMed1990

[Sense and nonsense of knee orthosis].

The trend for early mobility after surgical treatment of knee joint ligament injuries has led to the production of a large number of different braces in recent years. To allow an approximation of the very complex motion of the human knee, the use of braces with so-called physiological hinges has been recommended in the last few years. The authors report on a group of 50 patients who had sustained injuries to the cruciate ligament and had received IOWA knee braces following surgical treatment, the fit being subsequently checked by X-ray. These checks clearly demonstrated that the hinge of the brace hardly coincides with the knee axes and that there were deviations ranging from 1 to 4 cm. The authors therefore come to the conclusion that brace-fit must be checked by X-ray in all cases and that incorrectly fitted braces should be corrected before use. There is so far no evidence that so-called physiological hinges are really superior to braces with single axes. The current trends and developments cannot really be justified as long as there is no guarantee that the axes of brace and human knee coincide both in motion and during weight-bearing.

Adult↗
PubMed1985

Value of image enhancement and injection of contrast medium for right ventricular volume determination by two-dimensional echocardiography in congenital heart disease.

To determine factors that influence the accuracy of echocardiographically estimated right ventricular volume and to improve the echocardiographic input information by applying image enhancement techniques, quantitative contrast echocardiography (4-chamber view) and biplane angiocardiography were performed in 23 children during routine diagnostic cardiac catheterization. Volumes calculated on the basis of unprocessed and processed echocardiographic cross sections (area-length method and sphere model) underestimated angiocardiographic volumes significantly (p less than 0.01), and more so in end-diastole (50.6%) than in end-systole (35.9%). Thus, ejection fraction was significantly (p less than 0.01) underestimated; mean values were 0.48 +/- 0.12 and 0.60 +/- 0.08, respectively. The best comparison between echocardiography and angiocardiography at end-diastole was achieved with the sphere model using image enhancement techniques and injection of contrast media, where y = 0.54x - 6.8, r = 0.97, sy.x = 7.3. Correlations, however, in which unprocessed echocardiograms were used showed only slightly less good correlations. With the 6 image-enhancement techniques, a more homogeneous structure of the image and a more distinct outline of the internal surface was achieved. The statistical error improved only slightly. The echocardiographic 4-chamber view allows right ventricular volume determination with an acceptable accuracy. Its underestimation is related to inadequate visualization of trabeculations and mainly to the models used. Application of image enhancement techniques allows easier outlining of the internal cavity surface. The advantage gained by the combination of contrast infection and image enhancement techniques does not warrant the routine central injection of available contrast material.

Adolescent↗
PubMed1985

Assessment of cardiovascular function by digital angiocardiography.

A methodology for computerized digital videoangiocardiography is briefly described. Single or biplane projection image series from the cardiovascular system are combined with the corresponding physiologic (electrocardiogram, blood pressure, etc.) reference data, digitized and stored as a block of simultaneously available information representing anatomic and functional aspects of the cardiovascular system. Simple mask mode and more complex modes of digital subtraction, image combination and manipulation techniques, as developed during the last decade, are mentioned. These techniques are primarily useful to separate the contrast bolus from the background, thereby allowing contrast enhancement with less contrast medium injected selectively, or so-called noninvasive intravenous angiocardiography. Ventricular function can be assessed by these simple digital image processing techniques. This has been proved for determining right ventricular volumes and ejection fraction with respect to reproducibility and accuracy using conventional biplane angiocardiography as reference. More complex techniques for the assessment of function, in particular blood flow distributions in the systemic circulation, are described using information from the whole digitized angiocardiographic image series by extracting time and volume parameters from the complete matrix of pixel densograms. Various modes of extraction and display of time parameters allow a generation of parametric images that display heretofore unavailable flow patterns reflecting the progress of the contrast bolus within the arterial tree. Based on an adequate temporal segmentation (for example, time segments of one cardiac cycle) and simultaneous volume determination of the circulatory structure from the area of the densogram, relative and absolute flow as well as regional flow distribution in a branching arterial system can be determined.(ABSTRACT TRUNCATED AT 250 WORDS)

Angiocardiography↗
PubMed1985

Time and flow parameter extraction in digital angiography: principles and methods.

Indicator dilution techniques are used in the quantitative analysis of angiograms for time and flow measurements. In digital angiography the temporal changes of brightness are examined for each picture element. Certain functional parameters are evaluated and assembled in "parametric images". Flow distribution measurements are performed on the basis of two parametric images: A time parameter is used to define vascular segments that are passed by the blood flow in preselected time intervals. The depth parameter image provides for computation of the volume of each segment, which is used as the basis for regional blood flow calculation. Five time parameters and two depth parameters are described, differently suitable in various fields of application.

Angiography↗
PubMed1985

[Experimental measurements of renal circulation using digital functional angiography].

New techniques of digital image processing have been experimentally tested for the assessment of renal blood flow. The underlying principle in functional angiography is the extraction of flow parameters. Basically, density-time variations of the contrast medium are analyzed from each picture element of a 256 X 256 matrix. The real-time acquisition rate of images was 25/sec. For the calculation of angiographic flow a PDP 11/40 computer was used to interactively perform a time dependent segmentation of the renal arteries and the aorta. Subsequently, volume flow was calculated in relative units for the specific vascular segments under study. 15 control angiograms were made in 5 animals with cardiac output ranging between 0.8 to 2.2 l/min. Unilateral renal blood flow was calculated as 24 +/- 3.4% of pre-renal aortic flow without systematic side differences. Reproducibility from repeated flow measurements showed an SD of +/- 1.8% of the individual pre-renal aortic flow. Renal flow was also measured in 3 animals with an experimentally created 50% flow reduction of the left kidney. Angiographic flow in the left renal artery dropped to 12 +/- 2% of pre-renal flow. The present experimental data suggest that digital angiography has sufficient diagnostic capabilities for the detection of abnormal renal blood flow. The technique may serve as a useful diagnostic adjunct to conventional angiography and has the potential of assisting in the evaluation of renal vascular hypertension.

Angiography↗
PubMed1983

[Digital function angiography. A method of measuring arterial blood flow].

Digital image processing techniques can be effectively used for the quantitative evaluation of angiograms. In this study, the principle of parameter extraction from digitized image series was utilized. The procedure of parametric analysis was based on mathematical calculations of density-time-curves of the contrast medium according to each picture element of a digital image matrix (256 x 256 picture elements). Flow measurements were calculated from time parameter data and the subsequent segmentation of vessels indicating the propagation of the contrast medium within given time intervals. Flow velocity and volume flow studies will provide additional quantitative information to the evaluation of conventional angiograms.

Angiography↗
PubMed1982

Quantitative analysis of structure and function of the cardiovascular system by roentgen-video-computer techniques.

A survey of the evolution of roentgen-video-computer techniques is given which was initiated by the development of videodensitometry by Wood and his associates. Following fundamental studies of the usefulness and limitations of x-ray equipment for quantitative measurements and the applicability of the Lambert-Beers law to x-ray absorption, videodensitometry has been used experimentally and clinically for various circulatory studies and has proved to be particularly valuable for the quantitation of aortic, pulmonic, and mitral valvular regurgitation. The second offspring of these techniques, so-called videometry, uses dimensional measurements from single and biplane angiocardiograms for the assessment of size, shape, and contraction pattern of the heart chambers. Volumes of the right and left ventricles can be determined clinically with a standard error of estimate below 10%. On the basis of these studies, normal values have been derived for all age groups, and they depict geometric changes of the growing heart. Cardiac index and ejection fractions proved to be age-independent biologic constants. Finally, methods for complete digital processing of video-image sequences in an off-line and real-time mode are described which allow digital image storage and documentation, dynamic background subtraction for contrast enhancement, and intravenous angiocardiography, in addition to functional imaging by parameter extraction from a matrix of pixel densitograms. Wall thickness and motion determinations, regional flow distribution measurements, and various image-composition techniques are also feasible.

Absorptiometry, Photon↗
PubMed1981

Assessment of arterial blood flow measurements by digital angiography.

A system for computerized processing of video image series was utilized for the real-time digitization of arteriograms. There were 256 x 256 picture elements (pixels) per image with a resolution of 256 gray levels. Temporal changes in x-ray absorption at each pixel as induced by contrast media were computed for the extraction of regional blood flow parameters. Four steps of processing included: (a) vascular masking, (b) time parameter extraction, (c) segmentation of vessels, and (d) segmental volume and flow determinations. The results were displayed pictorially as angiographic parameter images. Measurement of the regional blood flow was tested at the abdominal arteries in nine pigs. Flow distribution values at the renal and iliac arteries were accurate within +/- 5% of the total abdominal aortic flow. The method may also be applicable to quantitative circulatory studies of the cerebral, pulmonary, and possibly, coronary arteries.

Angiography↗
PubMedDate not supplied

[Long-term results with cement-free total hip prostheses (Zweymuller)].

AIM OF THE STUDY: The purpose of the study is the evaluation of subjective, clinical and radiological long-term results of cementless total hip replacements with "Zweymüller" stems and various cups. METHOD: 113 of 165 consecutively implanted "Zweymüller" stems have been examined clinically and radiologically as well as assessed for subjective satisfaction by questionnaire, 26 additional patients were analysed by questionnaire only. Thus, the follow-up rate is 85.5% with a mean follow-up period of 8.9 years (range 5-12.2 years) as far as evaluation of subjective information including data on failures is concerned. The follow-up results were rated by the scores of Merle d'Aubigné and Harris and radiolucent lines on the X-rays were analysed. RESULTS: 96% of the analyzed patients stated subjective satisfaction. 101 hips caused no or only little pain. The average Harris Hip Score rose from 47.1 preoperative to 86.8 postoperative, the functional value of Merle d'Aubigné rose from 4.9 to 10.1 (maximum 12 points). The survival rate of the stems after 10 years is 96%, the complication rate is very low. 81% of the stems showed a proximal radiolucent line. 3 different kinds of cups were used, 79% of the polyethylene cups and 8% of the titanium cups, respectively, were loosened or had been explanted at the time of examination. CONCLUSIONS: During an observation period of 12 years, the implantation of the "Zweymüller" stem has very successful results. The proximal radiolucent lines should nevertheless cause concerns about the predominantly distal anchoring of the stem. The long-term survival of the stems is much better than that of the titanium cups.

Adult↗
PubMedDate not supplied

[The Kiel arthrograph--an instrument for recording active and passive shoulder joint mobility].

The authors describe a new method for measuring the flexibility of the shoulder. They have designed a device consisting of two electrical goniometers to measure the horizontal and the vertical position of the humerus. A computer registers these signals, calculates the region of mobility as a sperical segment centered to the shoulder joint (caput humeri). This region is displayed in a map, called arthrogram. Slightly modified, the arthrograph measures the rotation of the humerus and depicts the rotation angle into the map, at the site of the measurement. First results are reported. The procedure is reproducible with an error less than 5 degrees. Arthrograms of sound persons are compared to those of different pathological symptoms. Arthrograms show more information than single angular values. They can be viewed easily, e.g. to control the success of a treatment.

Biomechanical Phenomena↗
PubMedDate not supplied

[Comments on the use of the "life-table method" in orthopedics].

In the description of long term results, e.g. of joint replacements, survivorship analysis is used increasingly in orthopaedic surgery. The survivorship analysis is more useful to describe the frequency of failure rather than global statements in percentage. The relative probability of failure for fixed intervals is drawn from the number of controlled patients and the frequency of failure. The complementary probabilities of success are linked in their temporal sequence thus representing the probability of survival at a fixed endpoint. Necessary condition for the use of this procedure is the exact definition of moment and manner of failure. It is described how to establish survivorship tables.

Follow-Up Studies↗
PubMedDate not supplied

[The value of the anamnesis for the probability diagnosis of shoulder pain].

The response to pain of the shoulder in different diseases and injuries in this joint is uniform and this is of very little help in recognizing the cause. A detailed case history is useful in delineating the differential diagnosis. We have therefore developed a questionnaire consisting of 55 specifically aimed questions to these case histories. The acquired information was specifically rated for the 24 most frequent shoulderillnesses/injuries, and integrated in a computer program. In 55.4% of the cases the computer predicted the correct diagnosis and in 80% of the cases the right diagnosis was suggested amongst the first 3 preferences of the differential diagnosis.

Diagnosis, Computer-Assisted↗