Assessment of cup position from plain radiographs: impact of pelvic tilting

The acetabular cup position after total hip arthroplasty (THA) regarding its inclination and version angles are influential parameters concerning the postoperative range of motion and dislocation stability. Standard anterior-posterior X-rays remain an important diagnostic instrument to observe the postoperative outcome and to secure quality control after THA, where an optimal positioning of the patient is recommended when taking these X-rays. The purpose of this preliminary study was to determine the effect of pelvic tilting regarding the positioning calculation of the acetabular cup from standard radiographs using a modified method according to Pettersson et al. (Acta Radiol Diagn, 23:259-263, 1982). In our model experiment, we were able to show that pelvic tilting to either side causes a considerable difference between the radiographic and calculated version angles following approximately linear functions. However, pelvic tilting to either side, leads, regarding the calculation of the inclination, to an average deviation between radiographic and calculated inclination angles less than 2 degrees .

Theoretical investigation of excited states of C(3)

In this work, we present ab initio calculations for the potential energy surfaces of C(3) in different electronic configurations, including the singlet ground state [X (1)Sigma(g) (+),((1)A(1))], the triplet ground state [a (3)Pi(u),((3)B(1), (3)A(1))], and some higher excited states. The geometries studied include triangular shapes with two identical bond lengths, but different bond angles between them. For the singlet and triplet ground states in the linear geometry, the total energies resulting from the mixed density functional--Hartree-Fock and quadratic configuration interaction methods reproduce the experimental values, i.e., the triplet occurs 2.1 eV above the singlet. In the geometry of an equilateral triangle, we find a low-lying triplet state with an energy of only 0.8 eV above the energy of the singlet in the linear configuration, so that the triangular geometry yields the lowest excited state of C(3). For the higher excited states up to about 8 eV above the ground state, we apply time-dependent density functional theory. Even though the systematic error produced by this approach is of the order of 0.4 eV, the results give different prospective to insight into the potential energy landscape for higher excitation energies.

[Retransfusion of unwashed drainage blood after total hip and knee arthroplasty]

The method of retransfusion of drainage blood as known from the literature was investigated in a prospectiv study regarding effectivness and rate of side effects. 200 patients who underwent total hip and knee arthroplasty were investigated concerning hemoglobin, hematocrit, amount and quality of the retransfused drainage blood, the amount of autologous and homologous transfusions as well as complications and costs. 100 of these patients were selected as the control group. The amount of the retransfused drainage blood after hip arthroplasty amounted an average of 387 +/- 194 ml and after knee arthroplasty 595 +/- 250 ml. The retransfused blood had an average hemoglobin of 5,2 +/- 0,9mmol/l with a hematocrit of 0,24 0,05. No complications directly associated to the retransfusion were found. The need of transfusion was reduced for patients with knee arthroplasty about 30% and for hip arthroplasty about 25%. The retransfusion of unwashed drainage blood is a sufficient method to reduce perioperative homologous blood transfusion in patients with arthroplasty of hip and knee. Substantial complications were not observed, so that this method seems to be save enough for clinical usage. The method is easy to handle and usable without special technical devices. The autologous retransfusion of drainage blood can contribute to lower costs in patients treatement.

Clinical hyperthermia of prostate cancer using magnetic nanoparticles: presentation of a new interstitial technique

The aim of this pilot study was to evaluate whether the technique of magnetic fluid hyperthermia can be used for minimally invasive treatment of prostate cancer. This paper presents the first clinical application of interstitial hyperthermia using magnetic nanoparticles in locally recurrent prostate cancer. Treatment planning was carried out using computerized tomography (CT) of the prostate. Based on the individual anatomy of the prostate and the estimated specific absorption rate (SAR) of magnetic fluids in prostatic tissue, the number and position of magnetic fluid depots required for sufficient heat deposition was calculated while rectum and urethra were spared. Nanoparticle suspensions were injected transperineally into the prostate under transrectal ultrasound and flouroscopy guidance. Treatments were delivered in the first magnetic field applicator for use in humans, using an alternating current magnetic field with a frequency of 100 kHz and variable field strength (0-18 kA m(-1)). Invasive thermometry of the prostate was carried out in the first and last of six weekly hyperthermia sessions of 60 min duration. CT-scans of the prostate were repeated following the first and last hyperthermia treatment to document magnetic nanoparticle distribution and the position of the thermometry probes in the prostate. Nanoparticles were retained in the prostate during the treatment interval of 6 weeks. Using appropriate software (AMIRA), a non-invasive estimation of temperature values in the prostate, based on intra-tumoural distribution of magnetic nanoparticles, can be performed and correlated with invasively measured intra-prostatic temperatures. Using a specially designed cooling device, treatment was well tolerated without anaesthesia. In the first patient treated, maximum and minimum intra-prostatic temperatures measured at a field strength of 4.0-5.0 kA m(-1) were 48.5 degrees C and 40.0 degrees C during the 1st treatment and 42.5 degrees C and 39.4 degrees C during the 6th treatment, respectively. These first clinical experiences prompted us to initiate a phase I study to evaluate feasibility, toxicity and quality of life during hyperthermia using magnetic nanoparticles in patients with biopsy-proven local recurrence of prostate cancer following radiotherapy with curative intent. To the authors' knowledge, this is the first report on clinical application of interstitial hyperthermia using magnetic nanoparticles in the treatment of human cancer.

Interkorporelle Metallimplantate („Cages“) bei lumbalen Spondylodesen

Over the last 15 years, interbody metal implants have become commonly used worldwide for lumbar interbody fusion. The so called "cages" are made of metal or absorbable materials. By using different surgical techniques, they can be implanted either regularly or via endoscopy. The published results on surgical techniques using cages for the lumbar spine show, in most cases and with or without additional instrumentation, rates of fusion of more than 90%. It seems that the use of osteoinductive substances (especially BMP) leads to even better results. Dorsoventral fusion with internal fixation and bone show the same rate of consolidation, but the advantages of cages are primarily in the maintenance of the distraction and the possibility of a single surgical procedure without additional instrumentation (including endoscopy), and in a lower donor side morbidity.

[Musculoskeletal biopsies in an open 0.5-T-MR system]

INTRODUCTION

MR-guided interventions have been successful in different medical disciplines. The aim of this paper is to report our results with the application of MR-guided biopsies of musculoskeletal lesions using an open 0.5-T-MR scanner and further to discuss these results on the basis of the available literature.

PATIENTS AND METHODS

Between 1998 and 2003 30 patients (average age 44.1 years) underwent a total of 31 biopsies. The interventions were performed in an open 0.5-T MRI system using an active optical localization system as well as a navigation system. For the motion tracking we used T (1)-weighted real-time sequences with 0.25 pictures per second. For the sampling MR-compatible instruments were used that were specially developed for this purpose. The data of this retrospective investigation are based on the evaluation of the patient documents and the radiological findings. On the basis of the histological findings the technical success rate and the histological overall accuracy were determined.

RESULTS

In 81 % of the biopsies the histological diagnosis was correct. In cases of suspected inflammation the histological accuracy was smaller (70 %). No differences were observed between skeletal and soft-tissue lesions. The technical success rate amounted to 77.5 %. No procedural or anesthesiological complications occurred. The mean operating time amounted to 65 min including the time for motion tracking.

DISCUSSION

In cases of suspected lesions of the musculoskeletal system, the MR-guided biopsy represents a promising and safe procedure to get a histological diagnosis. In cases of sufficient size of the lesion sampling of a representative probe is possible. On account of the outstanding performance in soft-part contrasting, the sensitive structures surrounding the lesion can be saved. Substantial disadvantages of the procedure are the high costs for personal and material and the long operating time.

Pseudocontamination of blood components with Burkholderia cepacia during quality controls

We report on a pseudooutbreak of Burkholderia cepacia because of the use of a contaminated disinfectant during quality controls in a university blood bank. No septic reactions associated with transfusions had been reported in patients over the last 6 months. Analysis of the individual quality control procedures showed that a disinfectant based on a quaternary ammonium compound (QAC) had been used in order to disinfect the rubber stopper of the blood culture bottle. B. cepacia was found in a sample taken from this disinfectant, which was prepared with concentrate and tap water according to the manufacturer's instructions. The four isolates (one in disinfectant and three in blood components) were found to be identical in their biochemical reactions and resistance patterns. QAC-based disinfectants are not efficacious against a part of the spectrum of gram-negatives and are therefore inadequate. After introduction of an alcohol-based preparation, no more cases of B. cepacia contamination have been identified.

Evaluierung des Fügeverhaltens und der Rückhaltekräfte von Schnapp-Pfannen für den künstlichen Hüftgelenkersatz / Evaluation of the assembling and retention forces of constraint liners for total hip replacement

Dislocation is a severe complication after total hip replacement which may cause revision surgery in some cases. The use of constraint inserts that are coupled to the femoral head by a snapping mechanism provides an opportunity for treatment of recurrent dislocations. This study was aimed to investigate the assembling and retention forces of a specific constraint liner. Using a universal testing machine the assembling forces were determined for head sizes of 28 and 32 mm and the clinically mostly used as well as the maximum cup size. Subsequently, under variation of load direction and pull-out velocity the retention forces were investigated. For primary assembly of the head the required compressive forces were in a range from 197 N and 283 N depending on head and cup size (each size n = 3). Repeated assembly led to a decrease of these forces up to 29%. The retention forces always were slightly below the assembling forces, i. e. forces to remove the heads from the inserts were between 183 N and 230 N (each size n = 3). Repeated disconnection caused a decrease of the retention forces up to 16%. An increase of load velocity as well as an oblique load direction resulted in an enhancement of the retention forces. For all investigated implant sizes the retention force for the femoral head was approximately ten-times less than the interface strength between the insert and the metal-back. In case of correct implant handling the risk of disconnection between the tested constraint insert and the corresponding metal-back has not to be considered in clinical practice.

Short term efficacy and safety in glaucoma patients changed to the latanoprost 0.005%/timolol maleate 0.5% fixed combination from monotherapies and adjunctive therapies

AIMS

To evaluate efficacy and safety in patients with ocular hypertension or open angle glaucoma changed to latanoprost/timolol fixed combination (LTFC).

METHODS

A prospective, multicentre, historical control in which qualified patients had their previous therapy substituted by LTFC and were followed for at least 2 months.

RESULTS

In 1676 patients LTFC was continued in 93% throughout the observation period. In all patients LTFC reduced the intraocular pressure (IOP) from 20.6 (SD 3.8) to 17.7 (3.0) mm Hg (p<0.001) compared to previous monotherapies including latanoprost, timolol, alpha agonists or carbonic anhydrase inhibitors (CAI). LTFC provided more efficacy after changing from adjunctive therapies including: a beta blocker added to either CAI, alpha agonist, or pilocarpine, or CAI added to an alpha agonist, or latanoprost added to either CAI, alpha agonist, or beta blocker (unfixed combination), and travoprost added to timolol (p<0.007). LTFC was as effective as latanoprost used with dorzolamide/timolol fixed combination (-0.9 mm Hg, p = 0.1792). The most common reason to discontinue therapy was lack of efficacy (n = 70, 4%) and adverse event (n = 17, 1%).

CONCLUSION

In a clinical setting, patients who have their monotherapy or adjunctive therapy substituted with LTFC may experience reduced IOP, good tolerability, and continuation of therapy for the first 2-3 months of treatment.

Experimentelle Analyse von neutralen, asymmetrischen und Schnapp-Pfannen für die Hüftendoprothetik

AIM

Recurrent dislocation after total hip replacement is a severe complication, which requires specific treatment and implants. The purpose of the present study was to compare a constraint liner with an elevated rim and standard liner regarding their range of motion and dislocation stability.

METHOD

With a test device, range of motion until impingement (ROM (Imp)) and dislocation (ROM (Lux)) were experimentally analyzed using the above-mentioned insert types of a commercial total hip system. On the basis of movement combinations associated with dislocation, the ROM was determined. Further measuring parameter was the resisting moment against subluxation of the femoral head.

RESULTS

The constraint liners showed clear restriction of the movements "internal rotation combined with 90 degrees flexion and 0 degrees adduction" and "external rotation with 10 degrees extension and 15 degrees adduction" of up to 20 degrees compared to the neutral liner. ROM (Imp) was only decreased by about 8 degrees with the elevated-rim liner. The constraint liners revealed the highest resisting moments in subluxation, however, at adequate orientation in the acetabular cup the elevated-rim liners provided a higher ROM (Lux) of up to 12 degrees. Both designs were superior to the neutral liner at retroversion and steep cup position regarding resisting moment and ROM (Lux).

CONCLUSION

In case of insufficient soft tissue tension the use of constraint liners may increase the dislocation stability, however, in contrast to elevated-rim liners the impingement-free movement interval is clearly reduced. Thus, material damage and high shear stress in the bone interface can result. Therefore, constraint liners should only be used in exceptional cases.

[The German guideline clearing-project on bronchial asthma - part 2: recommendations and key topics for a national guideline on bronchial asthma]

BACKGROUND

In order to promote the quality of asthma management in Germany, a national asthma guidelines clearing project was initiated in 2000 by the German Guidelines Clearinghouse (Sponsors: German Medical Association (GMA), National Association of the Statutory Health Insurance Physicians (NASHIP), German Hospital Federation, Federal Association of the Statutory Sickness Funds. This Part shows the key topics which should be dealt with in a German guideline on bronchial asthma.

SUMMARY POINTS

For quality promotion of bronchial asthma management in Germany, the development of a national evidence-based guideline, using the internationally accepted quality criteria for clinical practice guidelines, was recommended by an expert group of the German Guideline Clearinghouse. The experts identified and peer-reviewed 16 out of 54 guidelines, which might be useful as benchmarks and examples for a German asthma guideline. From the peer review results, the expert group identified 18 key topics for a national asthma guideline.

Nosocomial outbreak of norovirus gastroenteritis and investigation of ABO histo-blood group type in infected staff and patients

The blood groups were analysed of staff and patients (N=45) infected during two nosocomial outbreaks of norovirus gastroenteritis at a German University hospital. Persons with O phenotype were significantly less affected than was expected from the normal distribution of blood group types in Southwest Germany (OR 2.45; 95% CI 1.22-4.95; P=0.01).

[MRI-guided pediatric interventions]

AIM

There are only a few diagnostic or therapeutic procedures where MR imaging is applied during pediatric interventions. This study will describe indications, complications as well as the advantages and disadvantages of MRI-guided interventions based on a case study in an open MRI scanner.

MATERIALS AND METHODS

14 procedures were performed in an open MRI scanner (Signa SP/i, GEMS) on 13 children (1 - 16 yr) with bone, soft tissue and brain lesions (1 - 4 cm diameter). Localization of the pathology, targeting and final control of the result were based on images acquired with SE-, 3D-, GE-sequences pre- and post-contrast as well as FSE-sequences. Interactive MRI-guided instrument navigation was performed using a multiplanar T1w GE-sequence.

RESULTS

Eight biopsies (incl. 1 rebiopsy), two tumor resections, one removal of a free joint mouse and three tumor-markings were performed without complications. Five biopsies provided appropriate sample quality for a histological diagnosis while two samples were too fragmented requiring a second biopsy (one of them MRI-guided). Surgical progress during tumor resection and marking could be controlled during the intervention without repositioning the patient.

DISCUSSION

MR image guided pediatric interventions combine the advantage of an imaging system without ionizing radiation and the high soft-tissue contrast. The low number of these kinds of procedures can be explained by the relatively high costs for the intervention, the increased duration for each procedure and the limited availability of open MRI systems. The integrated localization-system helps during planning of the access path when facing complex anatomical structures and provides safe navigation in sensitive regions like the epiphyseal cartilage. Recent and expected developments of the required MR-compatible biopsy instruments could provide higher efficiency for appropriate sample size and quality. Summarizing, MRI-guided pediatric interventions have shown to be a promising method at the beginning of its development.

Methode zur Evaluierung von Einflußfaktoren auf die Luxationsstabilität von künstlichen Hüftgelenken / Method for the Evaluation of Factors Influencing the Dislocation Stability of Total Hip Endoprotheses

Dislocation of the artificial joint is a serious complication of total hip replacement. Various factors with an influence on dislocation stability were determined clinically. Our goal was to develop a method for evaluating experimentally the parameters implant design, position and the load situation for their influence on joint stability. With the newly developed testing device the range of motion to impingement and to dislocation can be determined at different implant positions. In addition, the rotational moments on subluxation, i.e. the "levering out" of the femoral head, can be determined. By way of example several hip implants were examined during movements associated with dislocation, e.g. (internal-)rotation in 90 degrees flexion and 0 degrees adduction as well as with (external-)rotation in combination with 10 degrees extension and 15 degrees adduction. Irrespective of implant design and position, the following movement phases can be differentiated: undisturbed motion, impingement, subluxation and, finally, complete dislocation of the head. On the basis of the range of motion of the specific phases, the moments occurring and the direction of dislocation, different implant systems can be compared. In this study the influence of the head diameter on the dislocation stability of the hip endoprosthesis is shown. With the aid of the model presented herein, a data set showing the most favourable and/or most dislocation stable implant position can be acquired for different combinations of the implant components. Additionally, useful information for implant design can be deduced and applied to new developments and/or modifications of existing implant components.

[The German guideline clearing-project on bronchial asthma-part 1: Methodology and results of formal appraisal]

BACKGROUND

In order to promote quality of asthma management in Germany, a national asthma guidelines clearing project was initiated in 2000 by the German Guidelines Clearinghouse (Sponsors: German Medical Association (GMA), National Association of the Statutory Health Insurance Physicians (NASHIP), German Hospital Federation, Federal Association of the Statutory Sickness Funds. Part 1 of this article shows the methodology and the results of the appraisal, part 2 (to be published) shows the key topics which should be dealt with in a german guideline on bronchial asthma.

OBJECTIVES

To identify and compare evidence-based, high-quality German- and English language asthma guidelines as benchmarks for ongoing guideline development and implementation programmes. To disseminate information about asthma guidelines developed in accordance with current methodological know-how. To identify and consent key topics for a national evidence-based guideline for Germany.

METHODS

Search procedure, formal appraisal: Systematic search using literature databases (XMED, incl. Medline and Embase) and English-/German-language guideline databases (via www. leitlinien.de), published between January 1990 and March 2000. Abstract screening of the search results according to the inclusion criteria (n = 54 of a total of 502 hits). Methodological guideline evaluation of 16 guidelines using the German checklist for methodological guideline appraisal. Appraisal of guidelines' contents: Peer review of guidelines with the following inclusion criteria: Bronchial Asthma-general, German and English language, based in references published later than 1994, new guideline or actual update. Peer review was performed by a multidisciplinary focus group of EBM experts (clinical and ambulatory settings). No expert was involved in guideline production during the review period.

RESULTS

Methodological appraisal: 16 out of guidelines were in accordance with the formal minimal standard with a wide range within the following domains: "description of the development process", "declaration of authors' independence", "explicit link between recommendations and the supporting evidence", "management options", "tools for implementation". The focus group recommended for future national asthma guidelines to rely on the following procedures: (1) to formulate the recommendations using standardized, clearly described consensus methods basing on evidence retrieved and selected in a systematic way (2) to prove links between recommendations and supporting evidence (3) to develop guideline versions for health care professionals as well as for consumer/patients (4) to develop guideline-based education tools (5) to ensure periodical updates of the asthma guideline (6) to consider the methodological recommendations and to give reasons for deviations from the methodological recommendations. APPRAISAL OF GUIDELINES CONTENT: None of the guidelines identified comprised information about all of the following key topics considered to be relevant for a German national guideline by the focus group: (1) intended guideline users/goals, (2) definition (3) cause of disease, (4) form of disease, (5) severity, (6) diagnosis, (7) therapeutic goals, (8) prevention, (9) pharmacotherapy, (10) non-pharmacotherapy, (11) therapy control and compliance, (12) emergency treatment, (13) rehabilitation, (14) comorbidity, (15) special aspects, (16) coordination of care, (17) quality assurance/quality management, (18) implementation.

SUMMARY POINTS

For quality promotion of bronchial asthma management in Germany, the development of a national evidence-based guideline, using the internationally accepted quality criteria for clinical practice guidelines, was recommended by an expert group of the German Guideline Clearinghouse. The experts identified and peer-reviewed 16 out of 54 guidelines, which might be useful as benchmarks and examples for a German asthma guideline. From the peer review results, the expert group identified 18 key topics for a national asthma guideline.

[Treatment of periprosthetic femoral fractures associated with total hip arthroplasty]

AIM

Periprosthetic femoral fractures represent a heterogeneous type of injury with a variety of treatment options. By retrospectively analysing our data, the results of different therapeutic procedures are compared and, reviewing previously published cases, suggestions for the management have also been developed.

METHOD

This study is based on the analysis of records and radiograph series of 43 patients (50 procedures) with periprosthetic fractures. 22 patients could be followed-up using the Harris Hip Score at an average of 4.8 years after injury.

RESULTS

Factors predisposing to fractures were found in 41 patients, only 9 fractures were due to an adequate trauma. According to the classification of Johansson et al., 15 fractures of type I and type II each and 20 fractures of type III were treated. In 23 cases open reduction and internal fixation (ORIF) with a plate was used, 10 fractures were stabilised by minimal osteosynthesis, in 8 cases a modular prosthesis for bone replacement was used, 6 times a revison stem was implanted, and in 2 fractures osteosynthesis of the femur could only be accomplished after the complete removal of implants. The mean Harris Hip Score was 69.9 points at the follow-up examination. Local surgical complications were more often observed than general.

CONCLUSIONS

Due to their different clinical presentations periprosthetic fractures need to be managed individually and in most cases operatively. Internal fixation with a plate proved to give the best functional results for stable stem implants. Loosening stems have to be replaced by revision implants with long stems for intramedullary fixation. Alternative osteosynthetic techniques and additive minimal osteosynthesis can be favoured in special cases. Modular prostheses for bone replacement are reserved for fractures with extensive bone loss.