Biomedical subjects

S J Breusch

Publications and source records attributed to S J Breusch.

At least 19 recordsLinked to original sources

PubMed2003

[Fat embolism during total hip arthroplasty. Cementless versus cemented--a quantitative in vivo comparison in an animal model].

Thrombembolic complications,which include the fat embolism syndrome, are well-known consequences of cementless and cemented femoral total hip replacement. Thrombembolic phenomena have been demonstrated in clinical and experimental situations with both these fixation techniques, but so far no exact quantification of the intravasated fat emboli has been performed. In a standardized animal model in 15 Merino sheep we investigated the intravasation of fat into the bloodstream during simultaneous bilateral prosthetic implantation (cemented versus cementless). After identical preparation of the intramedullary canal on both sides, a cement restrictor was additionally inserted on the cemented side and the canal was cleaned by 250 ml jet lavage. Catheters in the external iliac veins made it possible to collect the drained blood in two phases, after preparation of the intramedullary canal and during insertion of the prosthesis, and the fat content of these blood samples was measured. The amount of fat that passed into the venous draining system of the femur induced by cemented implantation (2.2749 g; S=+/-1.0079) was twice the amount seen with cementless implantation (1.1586 g; S=+/-0.4555) ( P=0.0002). An obvious effect of the canal preparation was recognizable with the cemented implantation, 8 of the 13 animals evaluated showing a peak in the fat intravasation caused by application of the cement restrictor. Our results emphasize the importance of a thorough preparation of the intramedullary canal, particularly when cemented fixation is performed. The jet lavage,which should be considered mandatory standard in cemented total hip arthroplasty, should be implemented before the insertion of the cement restrictor in order to further reduce the risk of fat embolism.

Animals↗

PubMed2003

[Integration of periosteum covered autogenous bone grafts with and without autologous chondrocytes. An animal experiment using the Göttinger minipig].

Autologous osteochondral transplantation has the major disadvantage of significant damage to a healthy joint surface at the donor site. The purpose of this study was to examine the effect of autogenous chondrocytes injected into the periosteum of autologous bone grafts in order to provide an alternative method for cartilage repair. A total of 22 Göttinger minipigs were operated twice on both knees. The first operation served for cartilage biopsy for the chondrocyte culture. During the second operation an osteochondral defect was created in the medial facet of the trochlear groove. The defect was treated differently with an autologous cortico-cancellous bone cylinder,harvested from the proximal tibia.Group A: untreated defect (control);B: bone-graft;C: bone-graft covered with periosteum; D: bone-graft with periosteum and injected autologous chondrocytes. The animals were killed after 6, 12, 26 and 52 weeks. The regenerated areas were evaluated macroscopically, tested biomechanically (long-term specimens; indentation-test) and a histological, blind evaluation was carried out according to a semi-quantitative scoring system. The periosteum covered bone cylinders in Groups C and D showed good repair of the bone and cartilage defect. The repaired tissue consisted predominantly of fibrocartilage with the partial formation of hyalin like tissue. The regenerated areas were integrated with the adjacent cartilage and were biomechanically superior when compared with the other groups. The additional injection of chondrocytes did not produce significantly better results. Our findings suggest that the transplantation of periosteum-covered bone cylinders may provide an alternative method for treating chondral and osteochondral defects and can be recommended for filling large donor site defects in joint surgery. The additional transplantation of chondrocytes does not seem to be justified.

Animals↗

PubMed2003

[Bone substitutes].

A large variety of different bone substitutes are available for the treatment of congenital or acquired bone defects as an alternative to bone transplantation. Complications associated with graft harvesting, limited donor resources, and the potential risk of transmission of infectious diseases have led to the development of multiple concepts of new bone substitutes to minimize the wellknown problems. This article intends to give an overview of the products currently available on the market. Inorganic materials such as ceramics from hydroxyapatite and/or tricalcium phosphate, calcium phosphate cements, calcium sulfates and bioglass,organic materials (polymers) and composites, xenografts,and glass ionomer cements are discussed.

Bone Diseases↗

PubMed2003

[Bone cements based on polymethylmethacrylate].

Bone cements based on polymethylmethacrylate (PMMA) remain an important material for anchorage of artificial joints. Polymers based on PMMA originally developed for dental surgery have been successfully used in bone surgery for more than 40 years. At first sight the cold-curing PMMA bone cement seems to be a rather simple material consisting of a powder and a liquid. But in fact it is a complex material fulfilling various functions at its application site after the implantation. Its properties vary according to the composition of its basic elements. They already play a decisive role for the working behavior during mixing of both components. The differences in the working behavior considerably affect the cementing technique and the accurate application in vivo. These influence the mechanical performance of the cured cement mantle and the long-term results of the implantation. Standardized test methods are used to characterize bone cements,whereas the clinical relevance of the test methods has to be evaluated critically.Additionally,PMMA bone cements act as a drug delivery system as a local carrier of antibiotics. This paper gives a review of the composition and properties of PMMA bone cements and their influence on practical application.

Anti-Bacterial Agents↗

PubMed2003

[Stability and occlusion of six different femoral cement restrictors].

Cement restrictors play an integral part in modern cementing technique in total hip arthroplasty. By sealing the femoral cavity, distal cement leakage is prevented and the intramedullary pressure is increased. Thus both the ability of the cement to interdigitate with bone and secondarily the shear strength of the cement bone interface are enhanced. For this purpose various plug models are available, which differ in design and material. Six different cement restrictors were investigated in a biomechanical model with regard to intramedullary implantation pressure, insertion force and in particular stability and sealing ability. We performed a pressure and stability measurement in artificial saw bones during the insertion and standardised cement application and pressurisation. The REX Cement Stop, which is the only intramedullary expandable cement restrictor, yielded the best results in all of the parameters investigated. The flexible gelatin plugs (Biostop G, IMSET, Plugin Tech) also reached a sufficient canal occlusion and stability, but with slightly higher insertion pressures and forces. However, the more rigid polyethylene restrictors (BUCK, Universal Cement Restrictor) showed a reduced stability and poor sealing ability. The latter devices cannot be recommended for use with modern cementing techniques.

Arthroplasty, Replacement, Hip↗

PubMed2003

In vitro performance of intramedullary cement restrictors in total hip arthroplasty.

Contemporary cementing techniques in total hip arthroplasty include the use of a cement restrictor to occlude the intramedullary canal. As there are many different designs currently available it was the aim of our study to compare the stability of eight different systems. We investigated the displacement and the ability to occlude the femur of these cement restrictors during standardised cementing of artificial and fresh frozen femora. The maximal intramedullary pressures and the displacement of the plugs were continuously recorded and statistically evaluated. The results revealed significant differences between the tested cement restrictors. The expandable REX Cement Stop and the Exeter Plug achieved the highest stability and the least cement leakage. The more rigid designs (Palacos Plug, BUCK, Universal) in contrast showed inferior performance. Our biomechanical study emphasises the importance of cement restrictor selection, which can have a crucial influence on the fixation of a cemented total hip replacement.

Aged↗

PubMed2003

A ten- to 15-year follow-up of the cementless spotorno stem.

We followed the first 354 consecutive implantations of a cementless, double-tapered straight femoral stem in 326 patients. Follow-up was at a mean of 12 years (10 to 15). The mean age of the patients was 57 years (13 to 81). At follow-up, 56 patients (59 hips) had died, and eight (eight hips) had been lost to follow-up. Twenty-five hips underwent femoral revision, eight for infection, three for periprosthetic fracture and 14 for aseptic loosening. The overall survival was 92% at 12 years (95% CI 88 to 95). Survival with femoral revision for aseptic loosening as an endpoint was 95% (95% CI 92 to 98). The median Harris hip score at follow-up was 84 points (23 to 100). Radiolucent lines (< 2 mm) in Gruen zones 1 and 7 were present in 38 (16%) and 34 hips (14%), respectively. Radiolucencies in zones 2 to 6 were found in five hips (2%). The results for mid- to long-term survival with this femoral component are encouraging and compare with those achieved in primary cemented total hip arthroplasty. The high rate of loosening of the cup and the high rate of pain are, however, a source of concern.

Adolescent↗

PubMed2002

[New PMMA bone cements for vacuum mixing systems].

In cemented total hip replacement, fractures and cracks in the cement mantle may facilitate mechanical loosening of the prosthesis. Especially large voids and flaws within the cement can cause fatigue fractures. Reduction of cement porosity is a logical step in the attempt to improve the quality and durability of bone cement. An effective reduction of pores during vacuum mixing requires prechilling of Palacos R at 4 degrees C. For easier handling, new bone cements have been developed with characteristics similar to Palacos R, but with no chilling necessary prior to mixing under vacuum. In our study two newly developed bone cements (Palamed G, VersaBond) and a bone cement used widely in clinics (Palacos R) were mixed in three different vacuum mixing systems (Optivac, MixOR, Palamix). Macro-, micro-, and total porosity and bending strength (ISO 5833) were determined. All three mixing systems proved effective in reducing porosity and showed constant mixing results. All cement specimens that we tested fulfilled the ISO requirements for bending strength. VersaBond yielded the lowest porosities, but showed lower viscosity compared to Palacos R and Palamed G. The new cements are equal in vitro to Palacos R with regard to bending strength, but further clinical studies are necessary before widespread use is advisable.

Arthroplasty, Replacement, Hip↗

PubMed2002

[Influence of implant position of a hip prosthesis on alignment exemplified by the CLS shaft].

We performed a clinical and radiological analysis to evaluate the significance of the stem position of cementless CLS components with respect to function and survival. We used patient material from a multi-center study of 3,732 CLS stems with a mean follow-up of 43 months (range: 12-142 months). The clinical outcome was assessed using Merle D'Aubigné Scores and stem alignment was determined as the deviation of the longitudinal stem axis from the longitudinal femur axis. We found no correlation between stem alignment and function, survival, implant migration or periprosthetic radiolucent lines. In patients with rheumatoid arthritis and hip ankylosis the neutral stem position was less often achieved than in patients with other diagnoses. The results of our study cast doubt on whether the varus position of the femoral component of cementless tapered CLS-type stem designs is as critical as in cemented total hip arthroplasty.

Aged↗

PubMed2001

[Developments in hip hemi-arthroplasty and theory of the link-chain dimeric hip prosthesis].

Aim of the study was to analyze the developments of hemiarthroplasties from the femur prosthesis to the bicentric bipolar prosthesis of today. Using the theories published 1990 by Nägerl about "dimeric link chains", nineteen bipolar-head systems were analyzed and biomechanically explained. Clinical findings, such as the problems of luxation and varus positioning of the monocentric bipolars, as well as the valgus, "self-centric" positioning of the bicentric prosthesis are discussed and explained correctly by physics. The hemiarthoplasty with the bicentric bipolar system of today has realized the principles of the dimeric link chains and is superior concept. Eleven of the sixteen today available systems work like this concept which was reached by try and error. The function of a bicentric system is solved now and explained by physics.

Equipment Failure Analysis↗

PubMed2001

[Artefacts and ferromagnetism dependent on different metal alloys in magnetic resonance imaging. An experimental study].

The authors evaluated the significance of different metal alloys used in orthopaedic surgery in producing artefacts during magnetic resonance imaging. Several MRI sequences were tested and magnetic effects evaluated. Twelve discs made of different metal alloys from three manufacturers were examined. These discs were placed in a plastic box with a defined position in ultrasound gel. Then a sensitive, standard T1 weighted gradient echo sequence (TE: 4.1 ms; TR 9.4) was carried out in a coronal plane (Matrix 128/256). A Phillips Easy Vision workstation was used for image analysis. The largest area of artefact formation, including the surface size of the disc, was calculated using a special software program. In order to minimise the measurement error all discs were measured 10 times and the average value was determined. Then eight different sequences were run and measured in the same way. In a second series, all discs were placed separately on metric paper and subjected to the magnetic field of the MRI in order to detect possible motion secondary to the magnetic field applied. The different titanium alloys showed average distortion areas of from 245 mm2 (Ti6Al4V) to 349 mm2 (Ti5Al2.5Fe). Cobalt chrome alloys yielded differences of between 600 mm2 and 651 mm2 and iron alloys of between 902 mm2 (316L or Fe18Cr10NiMo) and 950 mm2 (Fe22Cr10Ni4Mn2MoNb) on average for the standard T1 weighted gradient echo. The artefact areas were dependent on the different sequences performed. For steel, (Fe18Cr10NiMo) areas of from 411 mm2 (T1TSE) to 2027 mm2 (EPI/3D/SPIR) were measured. All sequences studied produced different artefact pictures. None of the materials tested showed changes in position secondary to ferromagnetism. The size of signal distortion by MRI depends on the alloy making up the implanted material and the sequences used. The smallest artefacts occurred with the turbo-spin-echo sequences (TSE). The alloys tested in our study seem to carry no risk for patients of ferromagnetically induced secondary loosening caused by MRI scanning.

Alloys↗

PubMed2001

Dependency of cement mantle thickness on femoral stem design and centralizer.

Deficient cement mantles may be detrimental with regard to long-term outcome of cemented femoral stems. We performed a cadaver study on 48 left femora with 4 different stem designs (1 anatomic, 3 straight) to study the influence of stem design, centralizer, and femur type on cement mantle thickness. A radiographic and microradiograhic analysis was done. Overall, 88% of stems were aligned within 1 degrees of neutral in the frontal plane. In Gruen zones 1 through 7, we measured 24 thin cement mantles (<2 mm) in 19 specimens with no correlation to stem design or zone. In the sagittal plane, typical areas of thin cement mantles were identified in Gruen zones 8 and 9 (n = 39) and 12 (n = 21). The anatomic stem design carried the lowest risk (54%) of producing a thin cement mantle proximally in Gruen zones 8 and 9. The risk for straight stem designs was >90%. Straight stems without centralizer showed the highest risk of thin cement mantles in Gruen zone 12 (93%). Centralizers were efficient to prevent thin cement mantles in zone 12 but had no effect proximally. Lateral radiographs are essential to allow for adequate radiographic assessment of the cement mantle and stem alignment. There is a high risk of producing thin cement mantles in Gruen zones 8 and 9, in particular when straight stems are used. Posterior canal entry and low neck osteotomies are essential. Anatomic stems respect the anatomy, allow for more even cement mantles, minimize the risk of thin cement mantles without the use of centralizers, and may be considered in the femur with marked proximal bow.

Adult↗

PubMed2001

Cement penetration in the proximal femur does not depend on broach surface finish.

In a cadaver study, we prepared 29 paired human cadaver femora using 3 different broaches of identical geometry but different surface characteristics. In one group of 20 pairs, preparation with chipped-toothed broaches was compared to diamond-shaped broaches; in the other group of 9 pairs, polished tamps for compaction of cancellous bone were compared with chipped-tooth broaches. Cancellous bone was irrigated with 1 liter pulsed lavage. The specimens were embedded in specially-designed pots. Palacos R and Simplex bone cements were used. After vacuum mixing, the cement was applied in a retrograde manner and subjected to a standard pressure protocol with a constant force of 3,000 N. Radiographs were taken and horizontal sections were obtained at predefined levels using a diamond saw. Microradiographs were taken, digitized and analyzed to assess cement penetration into cancellous bone. In 6 of 9 femora prepared using smooth tamps, femoral fractures occurred despite careful preparation technique. The microradiographic evaluation showed no significant morphometric differences between diamond and chipped-tooth or between polished and chipped-tooth broaches with regard to cement penetration into cancellous bone. Therefore, in the presence of pulsed lavage, one finds no significant effect of broach surface characteristics on cement penetration into cancellous bone of the proximal end of the femur.

Absorption↗

PubMed2001

[Emission of air pollutants in removal of bone cement with ultrasound instruments in revision endoprosthetics].

The use of ultrasonic instruments to remove PMMA bone cement during revision hip arthroplasty results in the production of fumes. These emissions were analysed under standardized laboratory conditions, when it was found that the MMA concentration measured was only 1/10th of the MAC value. In terms of occupational safety, the MMA fumes emitted may therefore be considered non-hazardous for the medical personnel.

Air Pollutants, Occupational↗

PubMed2000

Ultrastructural findings after intraarticular application of hyaluronan in a canine model of arthropathy.

We investigated the effect of intraarticularly applied hyaluronic acid (hyaluronan) on the cartilaginous structure of experimentally induced chondromalacia patellae in dogs. For the induction of chondromalacia, we used the Pond-Nuki technique, which involved severance and resection of the anterior cruciate ligament, as a canine model of arthropathy in 27 foxhounds (three groups of nine animals each). In a pilot study, we evaluated the effect of resection of the anterior cruciate ligament with no therapy. Patellar specimens were retrieved at 3, 6, and 12 weeks postoperatively. Subsequently, we compared a treatment group that received intraarticular injections of hyaluronan with a placebo group that received saline solution. The groups were compared at 3, 6, and 12 weeks postoperatively. Three animals from the treatment and placebo groups received five injections of hyaluronan during one of the 4-week intervals (weeks 3-6, 6-9, or 12-15). Specimens were retrieved 5 weeks after the last injection. In both groups, the uninvolved contralateral knee served as a control. The specimens were taken from the medial and lateral patellar poles. Histological analysis included light microscopy and transmission electron microscopy. The structural and ultrastructural changes were assessed qualitatively and were quantified with use of a modified Mankin score. Our results indicate that chondromalacia patellae may be induced with the Pond-Nuki technique. We found a significant reduction (p < 0.01) of cartilaginous lesions in the hyaluronan group compared with the placebo group. Our results suggest that intraarticularly applied hyaluronan is effective in delaying the degenerative process of cartilage degradation. Therefore, we conclude that the use of hyaluronan may be indicated during the early stages of chondromalacia.

Adjuvants, Immunologic↗

PubMed2000

[Anchoring principles in hip endoprostheses. I: Prosthesis stem].

Total hip replacement is one of the most successful procedures in surgery. In Germany there is a great variety of cemented and uncemented implants with different principles of fixation. We reviewed the different principles, with particular reference to long-term clinical outcome, and discuss the most popular systems available in Germany. Despite many new developments which have been made in the field of cementless hip replacement, cemented total hip arthroplasty will remain the "gold standard" until prospective long-term data (> 15 years) of cementless systems become available.

Arthroplasty, Replacement, Hip↗

PubMed2000

[Anchoring principles in hip prosthesis implantation. II: Acetabulum components].

In this review the different anchorage concepts of cemented and cementless acetabular components are presented and clinical long-term results--if available--are discussed. Despite numerous design improvements and modifications the long-term durability of acetabular components remains a major concern with results being clearly inferior than achieved with femoral components. Until valid, prospective long-term success is proven for cementless designs cemented acetabular fixation using modern cementing technique must be regarded as standard treatment. However, successful fixation over 15-20 years very much depends on the quality of operative and cementing technique. Some cementless systems appear easier to use and have been documented to offer reliable mid-term survival rates. In young patients cementless devices have been well established and for some systems promising 10-year results have been published.

Acetabulum↗

PubMed2000

[Effects of the cementing technique on cementing results concerning the coxal end of the femur].

The purpose of this study was to determine the influence of jet-lavage and cement pressurising techniques upon cement penetration into proximal femoral cancellous bone. In a cadaver study 60 left human cadaver femora were used for implantation of cemented stem components. Four different groups of cementing techniques were generated, the allocation to the groups was randomized. Bone lavage was carried out either using jet-lavage or manual syringe lavage, cement application differed with regard to the amount of pressurisation used. Five different stem designs were used. Radiographs were taken and horizontal sections were obtained at predefined levels (2 cm) using a diamond saw. Microradiographs were taken and analysed using image analysis to assess cement penetration into cancellous bone. In an additional study the influence of jet-lavage (1000 ml) versus syringe lavage (1000 ml) was studied in 11 paired human cadaver femora. The specimens were imbedded in specially designed pots. Bone cement was applied in a retrograde manner and subjected to a standard pressure protocol with a constant force of 3000 N. The analysis protocol was identical to the main experiment. Both jet-lavage and pressurisation of bone cement significantly improved the penetration of cement into cancellous bone (p = 0.027 and p = 0.003, respectively). In the presence of strong, dense cancellous bone the findings were more pronounced. In the additional comparative study cement intrusion was significantly better (p < 0.001) in the jet-lavage group. We did not observe an influence of the stem type upon outcome (penetration). The use of jet-lavage yields significantly improved cement penetration and should be regarded mandatory in cemented total hip arthroplasty. High pressurising techniques are effective means to improve the interdigitation between cancellous bone and cement, but should only be administered in combination with jet-lavage to reduce the risk of thrombo-embolic complications.

Arthroplasty, Replacement, Hip↗