PubMed Health⌕ Search

Biomedical subjects

K Knahr

Publications and source records attributed to K Knahr.

60 records · Page 4Linked to original sources
PubMedDate not supplied

[Value of scintigraphy in aseptic loosening of cemented and cement-free hip endoprostheses].

Scintigraphic findings in 24 cemented and 25 cement-free prostheses were compared to determine the information value of scintigraphy in the diagnosis of loosening of total hip replacements. The scintigraphic findings were evaluated on the basis of specificity (indicates the percentage of complaint-free hips in which the scan is also negative) and sensitivity (indicates the percentage of clinically loosened hips in which the scan is also positive) in relation to the clinical diagnosis. For the cemented prostheses, the specificity value was 58% and the sensitivity 66%. The figures for the cemented prostheses were 15% and 83% respectively. On the basis of the authors' results it may be inferred that for cemented hip replacements the scan represents a valuable supplement to clinical and radiologic diagnosis. For the cement-free type of prostheses used by the authors, neither the scan nor radiology are suitable for diagnosing loosening; with these prostheses the findings obtained by clinical examination are the most reliable.

Bone Cements↗
PubMedDate not supplied

[Comparative studies on necrosis susceptibility of capsular tissue in arthrosis and endoprosthetic joint replacement].

We examined the rates of necrosis of newly formed capsula tissue (the number of newly formed capsular tissues with necrosis) after the reoperation of 95 cemented and 11 uncemented total and cup endoprostheses, consisting of different arteficial joint materials. A comparison was made to the joint capsular tissue of 492 patients with arthrosis. The necrosis rate shows a lack of statistical significance within the two year-groups over a period of 12 years and between the different types of prostheses by using PMMA-bone cement. Therefore, it is assumed that a biological equivalence of the prostheses wear products is reached. It is also argued that necrosis can possibly develop from the sudden increased accumulation of PMMA-bone cement particles from the bone bed, caused by the loosening of the prosthesis. In comparison the newly formed capsular tissue of the uncemented prostheses, of which no necrosis was shown, evidence is given that the development of necrosis is chiefly due the quantity of PMMA wear products present. Because of the difficulty to exactly identify the PMMA-bone cement wear products, the toxicity of the PMMA-bone cement--who ist good known and in agreement in recent literature--or its wear products continues to be of hypothetical value in the production of necrosis. This is inspite of the successful detection by the gaschromatograph of the highly toxic paratoliudine in PMMA-bone cement. On the basis of the high statistical significance of the rate of necrosis in comparing the arthrosis joint capsules (14.83%) to the newly formed capsules (73 : 100%) it is shown that the capsulare fibrosis and scar formation to the obliteration of the lymphatic vessels is of secondary importance.

Aged↗
PubMedDate not supplied

[Intertrochanteric rotational osteotomies in idiopathic femur head necrosis--comparison of different procedures].

PROBLEM: The aim of this study was to to compare different intertrochanteric osteotomies for avascular necrosis of the hip and to discuss it in the light of improving results of total hip arthroplasty. METHOD: 106 patients with diagnosis of avascular necrosis of the hip underwent an intertrochanteric osteotomy. During an interval of 14 years a total of 63 flexion osteotomies (partly combined with varisation or valgisation), 29 rotational osteotomies, 13 varisation osteotomies, 8 medializing osteotomies and 2 extension osteotomies were performed. The mean follow-up period for all osteotomies was 69 months (13-180 months). RESULTS: At the time of follow-up investigation, already 75.9% of patients with a rotational osteotomy had received a total hip arthroplasty, comparing to only 34.9% following flexion osteotomy. The Harris Hip Score of the remaining 7 rotational osteotomies was 86.5, for the 41 flexion osteotomies the HHS rated 73.8 points. A high incidence of early complications (55.2%) was seen after rotational osteotomies, compared to 17.5% after flexion osteotomy. For all osteotomies a high correlation between the size of the necrotic area (radiographic ap + axial necrotic sector) and the risk of failure can be demonstrated. Sugioka's rotational osteotomy showed only a very low probability of survival after 5 years (15.9%), in contrast to the flexion osteotomy (5a: 71.6%, 10a: 49.6%). The subgroup of flexion osteotomy with a necrotic sector < 180 degrees achieves the best survival probability of 89.2% after 5 years and 60.7% after 10 years. CONCLUSION: The indication for intertrochanteric osteotomies for avascular necrosis of the hip has to be discussed critically today. Good results can only be expected with small necrotic areas using the flexion osteotomy. It was impossible to obtain satisfactory long-term results with the rotational osteotomy due to a high risk of complications.

Adult↗
PubMedDate not supplied

[Evaluating the quality of life before and after implantation of a total hip endoprosthesis].

PURPOSE OF THE STUDY: Quality of Life of patients with Total Hip Arthroplasty is analysed before and one year after surgery. The evaluation included the functional capacity of our patients in every day life comparing the preoperative situation with the result one year after surgery. Age and duration of symptoms were analysed with respect to their influence on the success of the procedure. Finally the question should be answered, if clinical examinations and questionnaires concerning Quality of Life result in comparable data. METHOD: 101 patients with an average age of 64.2 years were included into this study. All patients were evaluated preoperatively and one year after surgery using the Harris Hip Score, questionnaires for Quality of Life of the patients included the Nottingham Health Profile and the Functional Questionnaire Hannover. RESULTS: The pre- and postoperative means of the Nottingham Health Profile showed in five of the six dimensions a significant improvement of Quality of Life (pain, mobility, energy, emotional reaction, sleep). Only the scale "social isolation" remained unchanged between the pre- and postoperative situation. The means of the functional capacity according to the Hannover questionnaire improved from 57.92 to 39.79, a highly significant result. The Harris Hip Score was poor in 97% of the preoperative evaluations. This score improved to 80.2% excellent or good, 7.9% fair and 11.9% poor at one year after surgery. Age and duration of symptoms had no influence in any parameter of Quality of Life. A classification of parameters on Quality of Life according to the Harris-Hip-Score at the 1-year results demonstrates a clear grading concerning the excellent and poor results. Based on the patients evaluations a differentiation between good and poor results is not recorded. CONCLUSIONS: The objective evaluation of results after implantation of a total hip joint-endoprosthesis should not be based only on clinical scores (f.e. Harris-Hip-Score). Subjective informations by the patients using questionnaires on Quality of Life (f.e. NHP, FFbH-R) have to be included into these evaluations. The different judgments of the outcome of surgery underline the necessity, not only to use clinical scores but also to include the patients' feeling into the interpretation of the clinical result.

Activities of Daily Living↗
PubMedDate not supplied

Cement-free bioceramic double-cup endoprosthesis of the hip-joint.

A cement-free bioceramic aluminum oxide double cup endoprosthesis is under investigation as an alternative to the cemented stem endoprosthesis. Nine patients with 11 operated hips are without complaints after an average of 20.8 months (range 8--28 months). Early loosening of 2 femoral components occurred because of technical mistakes during operation. In 3 patients loosening of the femoral component was seen 5--7 months after surgery. Mobilization of the hip joint and walking capacity are similar to the usually implanted stem endoprosthesis. Stable long-lasting anchorage is possible if the femoral component is implanted in valgus position and in contact with living bone. Failures are treated by a traditional type of endoprosthesis.

Adult↗