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Biomedical subjects

B W Schreurs

Publications and source records attributed to B W Schreurs.

At least 19 recordsLinked to original sources
PubMed2007

Biological activity of tri-calciumphosphate/hydroxyl-apatite granules mixed with impacted morsellized bone graft. A study in rabbits.

Reconstruction of bone defects with impacted morsellized cancellous bone grafts (MCB) is a popular method. Because of a shortage of human bone, mixing with biomaterials may be attractive. Ceramics may be used as bone graft extenders. In this study, various volume mixtures of biphasic tri-calciumphosphate/hydroxyl-apatite (TCP-HA) granules (1.5-2 mm) with MCB were examined in a non-loaded defect model in rabbits. Direct post-operatively, many 10-150 microm TCP-HA particles were present due to impaction. Irrespective to the group, after 8 weeks, virtually all MCB was resorbed and most TCP-HA granules were osseous-integrated with newly formed bone. The cross-sectional areas of TCP-HA after 8 weeks was generally smaller compared with direct post-operatively and the number of small 10-150 microm TCP-HA particles seemed reduced. Macrophages and giant cells were sparse after 8 weeks. In conclusion, the osteoconductivity of various mixtures of MCB and TCP-HA granules is not dependent on the ratio of TCP-HA over MCB. The reduced number of the 10-150microm TCP-HA particles after 8 weeks, may suggest that a cellular mediated resorption process of TCP-HA granules took place. Based on these favorable biological findings subsequent in-vivo experiments are warranted in load-bearing conditions to investigate whether these findings hold for joint reconstruction purposes.

Animals↗
PubMed2005

Sugioka's osteotomy for femoral-head necrosis in young Caucasians.

The transtrochanteric rotational osteotomy described by Sugioka is used to preserve the femoral head and to prevent secondary osteoarthritis in young patients with osteonecrosis of the femoral head. Several Japanese studies have shown favourable results, but European and American studies were disappointing. An explanation for these outcomes may be that the original protocol was not followed exactly. The objective of our study was to investigate this trans-trochanteric rotational osteotomy in Caucasian patients with osteonecrosis in which we followed the original method of Sugioka as closely as possible, including a 6-month period of non-weight bearing. We included 26 hips in 22 consecutive patients who were followed up for 8.7 (range 6.6-10) years. At review, 17 hips had been converted to total hip arthroplasty. The clinical survival rate was 56% after 7 years (95% CI 36-76%). The radiological survival rate was 54% after one year (95% CI 35-73%). Even after excluding the failures due to problems with osteosynthesis and infection, the results were not satisfactory and the osteoarthritic process was not delayed. Based on our results, we cannot recommend this technique as an alternative for total hip arthroplasty in Caucasians.

Adult↗
PubMed2005

Cemented cup stability during lever-out testing after acetabular bone impaction grafting with bone graft substitutes mixes containing morselized cancellous bone and tricalcium phosphate--hydroxyapatite granules.

Bone defects after failed total hip arthroplasty can be reconstructed with impacted morselized bone grafts and a cemented cup. In the near future the amount of bone grafts available for surgical purposes will be insufficient. Ceramic calcium phosphates [tricalcium phosphate (TCP) and hydroxyapatite (HA)] have been widely considered as potential bone graft substitutes or bone graft extenders. In the past, mechanical experiments have been performed to determine implant stability of bone grafts and ceramic TCP-HA granules mixes under a compressive load. However, in-vivo migration studies suggest that shear loading may be equally important. This in-vitro study investigated the initial stability of cups reconstructed with various mixes of bone grafts and ceramic TCP-HA granules in a lever-out situation, where shearing is the predominant loading mode. It was found that the cups reconstructed with mixes of bone graft and TCP-HA granules exhibited greater mechanical stability than the cups reconstructed with bone grafts only. It is concluded that from a mechanical standpoint, when considering shear force resistance, 50-50 per cent volume mix and 25-75 per cent volume mix of morselized cancellous bone graft and TCP-HA granules both provide adequate initial cup stability and can be used for acetabular reconstructions with the bone impaction grafting technique.

Acetabulum↗
PubMed2004

Was isolation of Veillonella from spinal osteomyelitis possible due to poor tissue perfusion?

From a needle biopsy of the body of the 12th thoracic vertebra in a 74-year-old man with spinal osteomyelitis a Veillonella parvula was isolated. The significance of this bacterium as lactic acid indicator has been considered and discussed. Since this strictly anaerobic bacterium mainly uses lactic acid for energy generation, lactic acid must continuously and sufficiently have been produced in or near to the vertebrate body to permit outgrowth of this bacterium. Since neither microbial infections nor tumours could be demonstrated, we finally hypothesised that in this patient poor tissue perfusion has been the primary cause of lactic acid production.

Aged↗
PubMed2004

Acetabular revision with impacted morsellised cancellous bone grafting and a cemented cup. A 15- to 20-year follow-up.

This study presents the clinical and radiological results of 62 consecutive acetabular revisions in 58 patients, at a mean of 16.5 years follow-up (15 to 20). The Kaplan-Meier survivorship for the cup with end-point revisions for any reason, was 79% at 15 years (95% confidence interval (CI); 67 to 91). Excluding two revisions for septic loosening at three and six years, and one revision of a well-fixed cup after 12 years in the course of a femoral revision, the survivorship was 84% at 15 years (95% CI; 73 to 95). At review there were no additional cases of loosening, although seven acetabular reconstructions showed radiolucent lines in one or two zones. Acetabular revision using impacted large morsellised bone chips (0.7 cm to 1.0 cm) and a cemented cup, is a reliable technique of reconstruction, when assessed at more than 15 years.

Acetabulum↗
PubMed2003

The initial stability of cemented acetabular cups can be augmented by mixing morsellized bone grafts with tricalciumphosphate/hydroxyapatite particles in bone impaction grafting.

Tricalciumphosphate (TCP) and hydroxyapatite (HA) have been suggested as bone graft substitutes in a wide range of applications. In this study, the initial stability of cemented acetabular cups was determined after reconstructing a combined cavitary and segmental defect in a realistic acetabular revision surgery model. The defects were reconstructed with mixes of TCP/HA particles and human bone grafts using the bone impaction grafting technique. In comparison with defect reconstruction with human bone grafts only, cup translation and tilt decreased by 27% when mixes of bone grafts and porous TCP/HA particles were used and by 55% when mixing the bone grafts with solid TCP/HA particles. Increasing the TCP/HA ratio within the mix significantly decreased cup translation. From a biomechanical perspective, mixes of TCP/HA particles and bone grafts are an attractive alternative for morsellized bone grafts when using the bone impaction grafting technique in the reconstruction of large defects of the acetabulum.

Acetabulum↗
PubMed2002

Effect of load on the early incorporation of impacted morsellized allografts.

Impacted morsellized bone grafts are clinically successful to restore bony defects after failed total hip arthroplasties. The incorporation process seems to be dependent on the location where the reconstruction is performed, which suggests that load could play a role. In this study, we hypothesised that, as in fracture healing, physiological loading has a stimulatory effect on the process of early bone graft incorporation. To test this hypothesis we created a standardised defect in the distal femur of twelve goats. Allograft bone chips were impacted into the defect and a subcutaneous pressure implant was screwed in. With this implant the graft can be loaded under controlled circumstances. Six goats were subjected to a daily loading regime of 3 MPa, the other six were non-loaded. After five weeks the bone mineral density was measured with peripheral quantitative computer tomography. Thereafter, routine histology and histomorphometry were carried out. Bone mineral density was not affected by load. Histology revealed microscopic evidence of bone graft incorporation, which proceeded in a similar way in both loaded and non-loaded specimens. New bone was formed free in the stroma or on graft remnants after osteoclastic resorption of the graft. Only the area of active incorporating bone graft was higher under load. In conclusion, the formation of a new bony structure was not affected by load after five weeks. However, load resulted in a larger area of active graft incorporation at this early stage. Possibly biological and immunological factors govern the early incorporation process independent of the local loading regime.

Animals↗
PubMed2002

Acetabular defect reconstruction with impacted morsellized bone grafts or TCP/HA particles. A study on the mechanical stability of cemented cups in an artificial acetabulum model.

In revision surgery of the acetabulum bone defects can be filled with impacted human morsellized bone grafts. Because of a worldwide limited availability of human bone, alternatives are being considered. In this study we compared the initial stability of acetabular cups after reconstructing a cavitary defect with various compositions of impacted tricalciumphosphate-hydroxyapatite (TCP/HA) particles and mixes of TCP/HA particles and human grafts in a realistic acetabulum model. Primary cemented cups and reconstructions with impacted human cancellous grafts were used as reference. A dynamic load displaced the acetabular cups superomedially. The primary cemented cups showed the highest stability. The cups with impacted human grafts produced the most displacement. All reconstructions with the TCP/HA particles showed a high stability of the cups. However, especially when using large TCP/HA particles this was probably due to a large amount of cement penetration. Mixing TCP/HA particles with human grafts seemed to decrease cement penetration. although still a high stability was obtained. In this perspective, we concluded that TCP/HA particles might be useful as a bone graft extender in the reconstruction of acetabular bone defects.

Acetabulum↗
PubMed2002

Do unloading periods affect migration characteristics of cemented femoral components? An in vitro evaluation with the Exeter stem.

Prosthetic migration has been identified as a marker for future revision of cemented total hip reconstructions. This could be tested at a pre-clinical stage with dynamic loading experiments. The purpose of this study was to assess the effects of resting periods, which are a considerable part of the daily activity cycle, on the migration characteristics of femoral cemented stems. Ten polished Exeter stems were implanted in composite femurs and loaded either with a continuous load or a discontinuous load. Continuous loading involved 345,600 loading cycles at 1 Hz, whereas the discontinuous loading involved loading at 1 Hz for 2.5 hours and a resting period of 21.5 hours for a period of four days. Hence, a total of 36,000 loading cycles were applied to these reconstructions. The subsidence patterns of the prostheses were considerably affected by the resting periods. The prostheses exhibited a step-wise migration pattern with migration steps of about 50 microns after every resting period, whereas the continuously loaded prostheses showed a more gradual migration pattern. The final subsidence of the specimens when loaded with resting periods was significantly less than the subsidence measured without resting periods. However, these specimens were loaded with fewer loading cycles. If this was taken into account, the discontinuously loaded specimens had a four fold higher average migration per loading cycle than the specimens that were loaded continuously. In conclusion, the resting periods had a considerable effect on the migration patterns, which should be realized when these stems are analyzed with pre-clinical tests.

Activities of Daily Living↗
PubMed2001

Time-dependent mechanical properties of HA/TCP particles in relation to morsellized bone grafts for use in impaction grafting.

In reconstructive surgery human bone defects are sometimes filled with the use of the impaction bone grafting technique. Currently different types of biomaterial particles are being developed as bone-substitute materials. Before these biomaterials can be applied their mechanical and biological behavior should be characterized. In this study the time-dependent mechanical behavior of biomaterial particles with different tri-calcium-phosphate/hydroxy-apatite (TCP:HA) ratios, particle sizes, and porosities is determined and compared to the behavior of human bone grafts, the latter being the standard material currently used to augment bone defects. The mechanical properties were assessed with the use of dynamic confined compression creep tests with a loading and unloading phase. Different graft material groups were tested, consisting of 100% human bone grafts, 100% biomaterial particles, and 50:50 weight mixtures of human grafts and biomaterial particles. No damage to the particles was observed by the impaction in the test chamber or by the dynamic load. Relative to the human graft material, the biomaterial particles hardly deformed under loading, were much stiffer, and showed almost no viscoelastic behavior. The mixtures showed intermediate results. Particle size and porosity influenced the behavior of the biomaterial particles. TCP:HA ratio did not have a great effect. The conclusion is that the application of these particles should be done with great care, as their mechanical behavior is drastically different than that of the human graft material. Mixing it with human bone grafts gave the material some biphasic, viscoelastic behavior that may be important for its biological response.

Biocompatible Materials↗
PubMed2001

Acetabular revision with impacted freeze-dried cancellous bone chips and a cemented cup: a report of 7 cases at 5 to 9 years' follow-up.

The long-term results of bone impaction grafting with fresh-frozen femoral head allografts and a cemented cup are favorable. Because of intermittent shortage of fresh-frozen femoral heads at our local bone bank, we used processed freeze-dried bone in 7 acetabular revisions operated between 1989 and 1994. All 7 consecutive patients were followed annually. At final review (March 2000), 1 patient had died after 8.5 years of follow-up of a cause not related to the surgery. In 1 hip, a rerevision was performed for septic loosening 5 years after the previous septic loosening. Radiographically the freeze-dried allografts seemed to incorporate in all cases but the reinfected one; progressive radiolucent lines were not seen, although 1 case had a stable line in 1 zone. The overall survival rate for the 7 acetabular reconstructions at an average follow-up of 7 years (range, 5-9 years) was 86%. At midterm follow-up, there was no aseptic loosening. In this limited case report, the results at midterm for freeze-dried allograft bone chips in acetabular reconstructions are acceptable.

Acetabulum↗
PubMed2001

Cemented total hip arthroplasty with impacted morcellized bone-grafts to restore acetabular bone defects in congenital hip dysplasia.

We evaluated the results of 27 acetabular reconstructions in 21 patients with secondary osteoarthritis resulting from congenital dysplasia of the hip in which the acetabular bone defects were restored with impacted morcellized bone-grafts in combination with a cemented cup. At an average follow-up of 7 years, 7 months (range, 5-15 years), 2 hips were revised. One cup was revised after 27 months for sciatic nerve problems; the other hip was revised for aseptic loosening of the cup at 12 years' follow-up. The cumulative survival of the acetabular reconstruction was 96.3% at 5- and 10-year intervals. Additionally, 2 hips (7.7%) showed stable radiolucent lines in zone III without migration of the cup. None of the cemented stems were revised. The bone impaction grafting technique is a safe and attractive method to restore bone deficiencies in dysplastic hips.

Acetabulum↗
PubMed2001

Favorable results of acetabular reconstruction with impacted morsellized bone grafts in patients younger than 50 years: a 10- to 18-year follow-up study of 34 cemented total hip arthroplasties.

We report a long-term review of 41 acetabular reconstructions using impacted morsellized bone grafts and a cemented total hip arthroplasty (THA) in patients younger than 50 (22-49; average 38) years. Reconstruction was performed in 23 primary THA (19 patients) and 18 revision THA (17 patients). 3 patients were lost to follow-up and 3 (4 hips) died within 10 years of surgery; none had a revision. Thus, 34 hips (30 patients) were reviewed with an average follow-up of 13 (10-18) years. In 2 hips, a revision was performed for aseptic loosening of the acetabular component 7 and 11 years after surgery. One additional cup was revised after 12 years during a femoral stem revision due to wear and matching problems, but was well fixed. The survival rate of the acetabular reconstruction technique was 94% (95% CI: 90-98%).

Acetabulum↗
PubMed2001

Acetabular reconstruction with bone impaction grafting and a cemented cup: 20 years' experience.

Acetabular bone stock loss compromises the outcome in primary and revision total hip arthroplasty. In 1979, a biologic method was introduced with tightly impacted cancellous allografts in combination with a cemented polyethylene cup for acetabular reconstruction. With this technique, it is possible to replace the loss of bone and to repair normal hip mechanics and hip function with a standard implant. Based on the authors' 20 years experience, a review of the long-term data is presented in primary total hip arthroplasty with preexisting acetabular bone stock loss, primary total hip arthroplasty in rheumatoid arthritis, patients who had bone impaction when younger than 50 years, and in acetabular revisions. The survival rate with revision of the cup for aseptic loosening as the end point was 94% at 10 to 17 years, 90% at 10 to 18 years, 91% at 10 to 17 years, and 92% at 10 to 15 years. From biopsy specimens from humans and histologic data in animal experiments the incorporation of these impacted bone chips was proven. The acetabular bone impaction technique using large morselized bone chips (range, 0.7-1 cm) and a cemented cup is a reliable technique with favorable long-term outcome.

Acetabulum↗