AIM: The purpose of this study was to identify typical radiological patterns of osseointegration following implantation of the Zweymüller-Alloclassic total hip system. METHOD: The follow-up included the clinical and radiological evaluation of 115 consecutive hips. For each case the screw direction of the cup was calculated individually to fully observe the bony surroundings by properly tilted X-ray beam. RESULTS: After 8.1 years, the Harris hip score was 88.5 points on average. Trabecular condensations leading toward the threads of the cup were observed in 100 cases, underlining the importance of the threads for load transfer. A complete intrusion of the threads into the pelvic bone was not accomplished in 23 cases with marked sclerosis of the acetabulum. The reduced connection, however, did not impair stability or function. The area of the distal stem is characterized by cortical hypertrophy and trabecular condensation of the neighbouring marrow. Linear radiolucencies were frequently observed in Gruen-Zone 1 and 7, in 5 cases extending into zone 2 and 6 without influence on the clinical function of the implant. CONCLUSION: Material and geometry of the Zweymüller total hip lead to a load transfer through the threads of the cup. The integration of the stem relies on cortical interlocking. Proximal linear radiolucencies do not impair function. The signs of osseointegration around the cup can be fully demonstrated only by a specially tilted X-ray beam at a right angle to the screw direction of the cup.

Adult↗

PubMedDate not supplied

[Value of the plain roentgen image and arthrography in diagnosis of loosening of cemented hip endoprostheses].

Radiographic signs of suspected prosthetic hip component loosening were evaluated by comparing them with the intraoperative findings. In 59 surgical procedures for suspected loosening of cemented total hip prostheses preoperative radiographic signs of loosening in plain radiographs and radiographic arthrograms were compared with the intraoperative findings. Radiolucent lines between the interfaces prosthesis/cement and cement/bone in defined zones (Salvati et al. 1976, Gruen et al. 1979) were evaluated. For the acetabular component relevant radiolucent lines were observed only between the interface cement/bone. A radiolucent line > 2 mm in zone 1, > 1 mm in zone 2a, a fracture or a retroversion were shown to be reliable signs for loosening with a specificity of 92%, a sensitivity of 61% and a predictive value of 97% (p < 0.01). For the femoral component a radiolucent line at the cement/bone interface of > 1 mm in any of the single zones 2, 3, 6 or 7 and radiolucent lines of > 0 mm in the combined zones 1 + 2 + 6 + 7 proved to be reliable signs of loosening. At the cement/prosthesis interface of the femoral component a radiolucent line of any width in zone 6 and radiolucent lines in the combined zone 1 + 2 or 1 + 7 proved to be reliable signs for loosening as well as major defects within the cement. The above mentioned signs of femoral component loosening display a specificity of 79%, a sensitivity of 86% and a predictive value of 81% (p < 0.001). Arthrography may be useful as an additional diagnostic means for the acetabular component (7 out of 18 false negative results in the radiograms were true positive in the arthrography. Penetration of the contrast material through all 4 zones yields a specificity of 83%, a sensitivity of 48% and a predictive value of 90% with p > 0.05), whereas for the evaluation of the femoral component loosening the gain of information is marginal compared with plain radiographs (specificity 80%, sensitivity 69% and predictive value 78% with p < 0.01). Hip component loosening can be identified with the above mentioned signs even if there are no previous radiographs available.

Arthrography↗

PubMedDate not supplied

[Dislocation following total hip endoprosthesis. Association with surgical approach and other factors].

During a period of eight years (1984 to 1992) we found 45 dislocations in 1734 patients treated by total hip arthroplasty. We compared this retrospectively evaluated group with a randomized control group of 61 patients. As a cause for an increasing number of dislocations in 1989 we found: age over 70 years, high CCD-stem-angle (142 degrees), dorsal approach, abduction of the acetabular component under certain circumstances (left side). Revision operations always are a high risk procedure. Acetabular anteversion, anaesthesia, way of component fixation did not induce an increased rate of dislocation. We now left the dorsal approach and use only stems with an CCD-angle of 135 degrees or less by now. Careful positioning of the acetabular components and a better patient-instruction helped to decrease the number of dislocations. Because of these measures we reduced the THA-dislocations rate from 5.6 to 0.17 per cent (first operations) and from 12.1 to 6.5 per cent (revision operations).

Aged↗

PubMedDate not supplied

[Cost analysis of a bone bank].

The costs of a bone-bank working in accordance with the guidelines of the german federal chamber of physicians are described. Establishing a bone-bank storing deep-frozen bone is not very expensive. The main costs are due to laboratory costs for excluding HIV, hepatitis, syphilis and bacterial contamination of bone grafts. In our experience with 206 bone grafts about 20% of them are to be discharged because of positive laboratory tests. The costs of each bone graft are DM 327. A second HIV-Test of the donor 3 months after explantation of a bone graft will cause rising of costs up to 47%. About 20-30% of bone graft donors will probably not carry out this test. In this case discharging of the bone graft is necessary.

Bacteria↗

PubMedDate not supplied

[5 years' infection statistics of an orthopedic clinic--pathogen spectrum, resistance status, therapeutic consequences].

In 1983 we started our statistical control for postoperative infections. The data are checked every half year. Most common bacteria was Staph. aureus followed by Staph. epidermidis. We found a difference in the spectrum of bacteria between our postop. patients and the referred cases. A surgeon related control and our new operating theatres reduced the infection rate from 2.2% to 0.8%. For our total joint replacements we additionally used perioperative antibiotics. The change in the antibiotic from Cefoxitine to Cefacedone reduced the infection rate from 4.7% to 0.8%. The permanent control of bacteria and of their resistance to antibiotics allows us to reduce the number of drugs used and to simplify treatment without loosing efficiency of therapy. This is--in a double sense--a good way for reducing costs.

Anti-Bacterial Agents↗

PubMedDate not supplied

Automatic detection of intradural spaces in MR images.

OBJECTIVE: An algorithm is presented for the automatic detection of intradural spaces in MR images of the human head. The primary motivation behind the present work has been to serve as a preprocessing step in automatic segmentation of brain tissue and CSF. A second objective was to use the algorithm in a fully automatic PET-MR registration algorithm. MATERIALS AND METHODS: The method is primarily designed for, and requires, dual echo (T1- and T2-weighted) MR images with transaxial orientations. The algorithm consists of three main stages. First, the head contour is detected using a series of low-level image-processing techniques. In the second stage, the pixels inside the head contour are clustered into a number of classes using the K-means algorithm. Finally, the extradural connected components are eliminated based on a number of heuristics. RESULTS: Test results are presented for 10 MR image sets consisting of 197 slices. As a quantitative measure of accuracy, manual segmentations were performed by radiologists on a number of slices and compared with the results obtained automatically. CONCLUSION: Visual inspection and quantitative validation of the results indicate that the algorithm accurately detects the intradural spaces in MR images. This is an important step in fully automatic segmentation and registration of MR images.

Algorithms↗

PubMedDate not supplied

A fully automatic multimodality image registration algorithm.

OBJECTIVE: A fully automatic multimodality image registration algorithm is presented. The method is primarily designed for 3D registration of MR and PET images of the brain. However, it has also been successfully applied to CT-PET, MR-CT, and MR-SPECT registrations. MATERIALS AND METHODS: The head contour is detected on the MR image using a gradient threshold method. The head region in the MR image is then segmented into a set of connected components using the K-means clustering algorithm. When the two image sets are registered, the segmentation of the MR image indirectly generates a segmentation of the PET image. The best registration is taken to be the one that optimizes the segmentation induced on the PET image. In this article, the K-means minimum variance criterion is used as a cost function, and the optimization is performed using the method of coordinate descent. RESULTS: The algorithm was tested on 80 H2 15O PET and MR image pairs from 10 subjects. Qualitatively correct results were obtained in all cases. With use of external markers visible in both image modalities, the average registration error was estimated to be < 3 mm. CONCLUSION: The algorithm presented in this article requires no user interaction and can be applied to a wide range of registration problems. Quantitative and qualitative evaluations of the algorithm indicate a high degree of accuracy.

Algorithms↗

PubMedDate not supplied

Design and construction of "SUMRIS"--the Sydney University magnetic resonance imaging system.

Explore the source record for details and available documents.

Australia↗

PubMedDate not supplied

Clinical outcome and subjective quality of life after photodynamic therapy in patients with age-related macular degeneration.

PURPOSE: Whereas the efficacy of photodynamic therapy (PDT) in preventing the progression of age-related macular degeneration (ARMD) is established, its effect on quality of life is under discussion. METHODS: All patients who underwent PDT during 2000 and 2001 at the University Eye Hospital of Mainz were interviewed using a standardized 82-item questionnaire on quality of life and patient satisfaction in ophthalmologic patients. Information was assessed in terms of 82 questions; global scores ranging from 1.0 (optimum self-estimated quality of life) to 4.0 (worst) were derived. Cataract patients' scores were used to characterize the ARMD patients' subjective outcome; the latter were then related to clinical outcome parameters via logistic regressions. RESULTS: A total of 84 patients (50% female, median age 77 years) were interviewed, who underwent a median of three PDT interventions. During the period of PDT treatment, their median decrease in visual acuity was 3 lines from 0.125 to 0.063. Patients who reported a subjective increase in visual function during this period showed a median private flexibility score of 1.86; patients with the subjective impression of visual function decrease, a median score of 2.71; the median scores for mobility were 2.00 versus 3.00, for flexibility in reading 1.91 versus 3.64, for psychological stress 1.56 versus 2.25, and for communicational flexibility 1.72 versus 2.25. The difference in reading flexibility was statistically significant (p=0.001) after correction for clinical cofactors. CONCLUSIONS: The established clinical benefit of PDT treatment concerning its efficacy in ARMD progression prevention coincides with an at least slight subjective benefit in quality of life and patient satisfaction. However, the latter is associated with the patients' subjective impression of visual acuity progression rather than with clinically validated outcome after PDT treatment.

Activities of Daily Living↗

PubMedDate not supplied

Tumor-biological factors uPA and PAI-1 as stratification criteria of a multicenter adjuvant chemotherapy trial in node-negative breast cancer.

In axillary node-negative primary breast cancer, 70% of the patients will be cured by locoregional treatment alone. Therefore, adjuvant systemic therapy is only needed for those 30% of node-negative patients who will relapse after primary therapy and eventually die of metastases. Traditional histomorphological and clinical factors do not provide sufficient information to allow accurate risk group assessment in order to identify node-negative patients who might benefit from adjuvant systemic therapy. In the last decade various groups have reported a strong and statistically independent prognostic impact of the serine protease uPA (urokinase-type plasminogen activator) and its inhibitor PAI-1 (plasminogen activator inhibitor type 1) in node-negative breast cancer patients. Based on these data, a prospective multicenter therapy trial in node-negative breast cancer patients was started in Germany in June 1993, supported by the German Research Association (DFG). Axillary node-negative breast cancer patients with high levels of either or both proteolytic factors in the tumor tissue were randomized to adjuvant CMF chemotherapy versus observation only. Recruitment was continued until the end of 1998, by which time 684 patients had been enrolled. Since then, patients have been followed up in order to assess the value of uPA and PAI-1 determination as an adequate selection criterion for adjuvant chemotherapy in node-negative breast cancer patients. This paper reports on the rationale and design of this prospective multicenter clinical trial, which may have an impact on future policies in prognosis-oriented treatment strategies.

Biomarkers, Tumor↗