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Biomedical subjects

N Schürmann

Publications and source records attributed to N Schürmann.

12 recordsLinked to original sources
PubMed2004

In vitro and in vivo performance of Ti6Al4V implants with plasma-sprayed osteoconductive hydroxylapatite-bioinert titania bond coat "duplex" systems: an experimental study in sheep.

To evaluate the in vivo performance of "duplex" hydroxylapatite top coat/TiO(2) bond coat systems, cylindrical Ti6Al4V rods of 130 mm in length and 11-13 mm in diameter were coated by atmospheric plasma spray (APS) technique with both a standard hydroxylapatite (HAp) layer and a HAp+TiO(2) bond coat "duplex" layer. In this pilot study coated and uncoated rods serving as controls were implanted into the femur of sheep so that their distal ends were freely suspended in the medulla of the femur. After an observation time of six months it was found that bone apposition and bone ingrowth were considerably increased in the presence of a osteoconductive coating. In particular, in vivo spalling and delamination frequently observed with HAp coatings was virtually absent in duplex coatings owing to the strong adhesion of the bond coat to the HAp top coat that anchored the latter solidly to the metallic surface of the implant. Some tentative mechanisms leading to this improved coating adhesion will be discussed.

Alloys↗
PubMed2001

[Cost analysis of hip and knee prostheses as the basis for cost-benefit evaluation].

INTRODUCTION: The diagnosis-related reimbursement for total hip- and knee arthroplasty is often interpreted as a claim for cost reduction and thus influences increasingly the surgeon's choice of treatment. With regard to further planned budget reductions the following questions arise: Remains quality payable? Where are cost savings possible? PATIENTS AND METHODS: Prospective analysis of 21 patients with primary hip- and 26 with knee arthroplasties to identify all cost factors during the hospitalization period including the implantation technique and quality improvement measures. RESULTS: Expenses of 18,763.26 DM for hip- and 18,649.40 DM for knee implants were covered by the diagnosis-related reimbursement. Compared to cemented implants, the average total costs of cementless prostheses were usually less expensive. CONCLUSION: Although the current costs are covered, a further reduction of the diagnosis-related reimbursement may result in a loss of quality. The present cost analysis outlines a guideline for an individual calculation and assessment of possible saving effects.

Aged↗
PubMed2000

[Early loosening of a cemented hip endoprosthesis stem of titanium].

Up to now there are no facts concerning the loosening rate of the cemented titanium stem (Trios). The central guiding canula and the longitudinal drilled stem shall ensure a symmetric cement mantle. In order to estimate the risk of aseptic loosening all Trios prostheses implanted in our clinic (n = 67; operations 1/95-11/96; max. follow-up: 3.1 years) were examined in a retrospective study and compared with a conventional femoral component (n = 141; Müller special; CoCr; operations 1977-1982). We used survivorship analysis to assess the results (Kaplan-Meier method; end point: revision). Compared to the conventional femoral stem the survival rate of the Trios prostheses was significantly worse (p = 0.0001). The probability of no revision after 3 years was 72% (conventional femoral component: 96%). Preoperative x-rays showed radiolucent lines surrounding the cement mantle. These findings as well as the loosening at the cement metal interface were confirmed intraoperatively. The explanted stems showed corresponding signs of abrasion on the surface. Our results prove that the application of cemented titanium stems might be problematic. With regard to the Trios prosthesis we recommend close routine check-ups to keep the chance of an early revision.

Aged↗
PubMed1999

Shear strength of the cement metal interface--an experimental study.

The shear strength of the cement-metal interface using rods with different surface treatments and a clinical standardized cementing technique was studied. Under "dry" conditions, a low interface shear strength can be obtained with polished and smooth CoCrMo surfaces (peak-to-valley height Rt: 1 microm, average 0.2 MPa; 5 microm, 0.38 MPa). Grit-blasted and polymethylmethacrylate (PMMA)-precoated surfaces achieved higher values (PMMA precoat: average 5.16 MPa; CoCrMo peak-to-valley height Rt: 20 microm, average 8.61 MPa: 60 microm, average 7.8 MPa). After immersion in physiological saline solution for 60 days, the PMMA-precoated rods kept their initial stability whereas all the other test rods had lost their stability completely. A microscopic analysis of cross-sections revealed gap formations at the cement-metal interface to varying degrees (1-16 microm). PMMA-precoated rods rarely showed any gap formation at all. The above-mentioned gap formation was seen independently of the porosity at the cement-metal interface and corresponds to the clinical and postmortem observed debonding of the interface.

Biomechanical Phenomena↗
PubMed1993

[Arthroscopy of the upper ankle joint. List of indications from the literature--realistic expectations--complications].

Based on the results of a retrospective study of 116 patients who underwent diagnostic and surgical arthroscopy of the ankle, we present the technique, the results, the complications, and the indications for ankle arthroscopy. The average age of the patients was 33 years (range 10-70 years). At follow-up the patients were examined clinically as well as radiologically. The results were scored for the criteria pain, function, athletic activity, walking aids, range of motion, and swelling. The overall score increased significantly from 50.1 preoperatively to 73.7 postoperatively (P < 0.05). The decrease in pain and the improvements in function and athletic activity after arthroscopy were significant. The other parameters (walking aids, range of motion, swelling) showed only slight changes. The patients' subjective assessment (visual analogue scale) also revealed a significant increase, from 35.6 to 69.5 (P < 0.05). After arthroscopy the preexisting radiologic lesions continued to progress. Some 71.2% of the patients suffered no limitations their work at follow-up but 13.6% reported slight limitations and 15.3% experienced moderate limitations. We documented severe restrictions in athletic activity; only 17% of the patients had maintained their previous level. In 16 cases we found iatrogenic temporary neurologic damage.

Adolescent↗
PubMed1990

Single dose pefloxacin compared with multiple dose co-trimoxazole in cystitis.

In a double-blind multicentre study the efficacy and safety of a single-dose treatment with pefloxacin (800 mg) was compared with a five-day treatment regimen of 960 mg co-trimoxazole twice daily in the therapy of acute uncomplicated cystitis in women. In order to maintain blindness, patients in the pefloxacin group received placebo to complement the full number of tablets. Nine centres were involved; 155 patients received pefloxacin and 161 patients received co-trimoxazole. Of these, 140 patients treated with pefloxacin and 145 with co-trimoxazole were considered valid for efficacy and safety analysis. At the first follow-up, after seven to ten days, 97.1% of the pefloxacin group and 95.2% of the co-trimoxazole group were bacteriologically cured. At the second follow-up visit, after 28 to 42 days, the urine culture was negative in 95.0% of the pefloxacin group and 90.3% of the co-trimoxazole group. A single dose of 800 mg pefloxacin was demonstrated to be as safe and at least as effective as a five-day regimen of co-trimoxazole in the treatment of uncomplicated cystitis.

Adult↗
PubMedDate not supplied

[Primary hip- and knee arthroplasty--comparison of the actual costs with the Australian diagnosis related groups (DRG)-].

AIM: With the introduction of the Australian DRG system in Germany the question arises which current procedures remain reasonable in cost. The present study compares the actual costs with the expected DRG reimbursement. PATIENTS AND METHODS: Prospective analysis of 23 patients with primary hip and 26 with knee arthroplasty was performed to identify all cost factors during the hospitalization period including all applied measures. Retrospective analysis was carried out of the additional costs of relevant concomitant diseases (liver transplantation, haemophilia). RESULTS: Expenses of 6231 euro; for hip and 6453 euro; for knee implants were covered by the DRG reimbursement. Although a special reimbursement was paid, the additional costs of the concomitant diseases resulted in a financial loss. CONCLUSION: To cover the current costs for patients free of complications, an enormous reduction of the length of stay is required. Otherwise complicated cases may result in a loss of quality or selection of patients. The present cost analysis outlines a guideline for an individual calculation and assessment of the necessary DRG reimbursement.

Adult↗
PubMedDate not supplied

[Quality and management of preoperative patient information. Results of conventional and computer based documentation].

INTRODUCTION: Analysis of the quality of different modes of preoperative information management on the example of primary total hip arthroplasty. Comparison between a since 10 years used, computer based system and a conventional procedure with additional hand-written notes. METHODS: Retrospective analysis of respectively 50 with conventional and computer based system written preoperative patient information. The completeness of the documentation is examined according to the demands of current judgement. RESULTS: The results confirm, independent from the level of education, a complete documentation of all risks by applying the computer based system, whereas the conventional method leads to considerable lacks of documentation. DISCUSSION: The computer based system guarantees a high quality of preoperative patient information which cannot be obtained by the conventional method and therefore offers a protection against unjustified claims of liability.

Ambulatory Care Information Systems↗
PubMedDate not supplied

[Nerve lesions after hip prosthesis implantation--fate or treatment error?].

INTRODUCTION: Nerve lesions after hip arthroplasty are common complications which may imply the reproach of a treatment mistake. Thus, the decisive question to the expert runs: fate or treatment mistake? METHODS: Retrospective analysis of all cases dealt with at the medical expert commission of the General Medical Council Nordrhein during 1977-1997 in respect of the damage mechanisms and expert judgments. RESULTS: As long as diagnosis and therapy were set on time, nerve lesions after hip arthroplasty due to extension, pressure or placement of the leg were evaluated as fateful (81%). Delayed treatment as well as incorrect operation technique, -indication, or inadequate documentation were judged as a treatment mistake (19%). CONCLUSION: Nerve lesions after hip arthroplasty cannot always be avoided and thus do not directly imply a treatment mistake. Immediate therapy and precise documentation are important to minimize the damage.

Arthroplasty, Replacement, Hip↗