Publications by authors named "Steven M van Gaalen"

15 Publications

  • Page 1 of 1

Non-equivalent Results from Different Anteversion Measurements Methods for the Evaluation of the Acetabular Cup Orientation in Total Hip Arthroplasty.

Orthop Surg 2019 Apr 1;11(2):241-247. Epub 2019 Apr 1.

Clinical Orthopedic Research Center - mN, Diakonessenhuis Zeist, Zeist, the Netherlands.

Objective: To determine the comparability among 10 radiographic anteversion methods for acetabular cup orientation in total hip arthroplasty (THA) found in the literature and the "gold" standard of assessing the anteversion with CT.

Methods: This is a retrospective study that blindly compares 10 different conventional radiographic anteversion measurements with the "gold" standard, the measurement of anteversion on the transverse plane of the 3-D images made with CT. The patient archiving and communications system (PACS) was systematically searched for subjects that had undergone a CT angiogram of the abdomen and lower extremities, including the pelvis, had at least one THA in situ and had undergone anterior-posterior (AP) and cross-lateral pelvic radiography between January 2013 and August 2016 in the Diakonessenhuis Hospital Utrecht/Zeist, a non-academic institution. CT scans of patients (n = 16) were systematically collected. Three observers independently measured cup anteversion from radiographs, using a total of 10 different methods, and measured the "gold" standard on CT images. The outcomes of the 10 radiographic anteversion were compared in terms of linear correlation with the "gold" standard on CT images.

Results: The correlations of the radiographic measured anteversions with the "gold" standard measured on CT images were 0.528 for the method of Liaw, 0.556 for Wan, 0.562 for the cross-lateral method, 0.586 for Hassan, 0.594 for Dorr, 0.602 for Lewinnek, 0.624 for Widmer, 0.671 for the lateral CT, 0.747 for Ackland, and 0.771 for the method of Riten Pradham.

Conclusion: Anteversion measurement methods represent different projectional angles of the acetabular cup in different planes around different axes. Therefore, they differ from the "gold" standard and are not interchangeable, as is shown by this study. We consider the anatomical anteversion in the transverse plane rotating around the longitudinal axis as the "gold" standard and recommend avoiding using the term anteversion for other projectional angles in different planes.
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http://dx.doi.org/10.1111/os.12445DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6594505PMC
April 2019

Injuries related to bicycle accidents: an epidemiological study in The Netherlands.

Eur J Trauma Emerg Surg 2020 Apr 15;46(2):413-418. Epub 2018 Oct 15.

Departement of Orthopaedics, Diakonessenhuis Utrecht/Zeist, Utrecht/Zeist, The Netherlands.

Background: This study aims to analyze the incidence and outcomes of bicycle-related injuries in hospitalized patients in The Netherlands.

Methods: Bicycle accidents resulting in hospitalization in a level-I trauma center in The Netherlands between 2007 and 2017 were retrospectively identified. We subcategorized data of patients involved in a regular bicycle, race bike, off-road bike or e-bike accident. The primary outcomes were mortality rate and incidence of multitrauma. Secondary outcomes were differences between bicycle subcategories. Independent risk factors were identified using multivariable logistic regression. All variables with a p value < 0.20 in univariable analysis were entered in multivariable analysis.

Results: We identified 1986 patients. The mortality rate after emergency room admission was 5.7%, and 41.0% were multitraumas. A higher age, multitrauma and cerebral haemorrhages were independent risk factors for in hospital mortality. Independent risk factors found for multitrauma were a higher age, two-sided trauma, e-bike accidents and cerebral haemorrhage.

Conclusion: Bicycle accidents resulting in hospitalization have a high mortality rate. Furthermore, a high incidence of multitrauma, fractures and cerebral haemorrhages were found. Considering the increasing incidence of bicycle accident victims needing hospital admission, new and more efficient prevention strategies are essential.
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http://dx.doi.org/10.1007/s00068-018-1033-5DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7113215PMC
April 2020

Comparison of polyetheretherketone versus silicon nitride intervertebral spinal spacers in a caprine model.

J Biomed Mater Res B Appl Biomater 2019 04 9;107(3):688-699. Epub 2018 Aug 9.

Department of Orthopedic Surgery, Clinical Orthopedic Research Center midden-Nederland (CORCmN), Diakonessenhuis, Utrecht, The Netherlands.

Polyetheretherketone (PEEK) is commonly used as a spinal spacer for intervertebral fusion surgery. Unfortunately, PEEK is bioinert and does not effectively osseointegrate into living bone. In contrast, comparable spacers made of silicon nitride (Si N ) possess a surface nanostructure and chemistry that encourage appositional bone healing. This observational study was designed to compare the outcomes of these two biomaterials when implanted as spacers in an adult caprine model. Lumbar interbody fusion surgeries were performed at two adjacent levels in eight adult goats using implants of PEEK and Si N . At six-months after surgery, the operative and adjacent spinal segments were extracted and measured for bone fusion, bone volume, bone-implant contact (BIC) and soft-tissue implant contact (SIC) ratios, and biodynamic stability. The null hypothesis was that no differences in these parameters would be apparent between the two groups. Fusion was observed in seven of eight implants in each group with greater bone formation in the Si N group (52.6%) versus PEEK (27.9%; p = 0.2). There were no significant differences in BIC ratios between PEEK and Si N , and the biodynamic stability of the two groups was also comparable. The results suggest that Si N spacers are not inferior to PEEK and they may be more effective in promoting arthrodesis. © 2018 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 00B: 000-000, 2018. © 2018 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 107B: 688-699, 2019.
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http://dx.doi.org/10.1002/jbm.b.34162DOI Listing
April 2019

Temporary Segmental Distraction in a Dog with Degenerative Lumbosacral Stenosis.

Vet Comp Orthop Traumatol 2018 Jul 2;31(4):298-303. Epub 2018 Jun 2.

Division of Orthopaedics/Neurosurgery, Department of Clinical Sciences of Companion Animals, Faculty of Veterinary Medicine, Utrecht, The Netherlands.

Objectives:  Degenerative lumbosacral stenosis (DLSS) is characterized by intervertebral disc degeneration and causes lower back pain in dogs. Temporary distraction in rabbit models with induced intervertebral disc degeneration showed signs of intervertebral disc repair. In the present study, we assessed safety and efficacy of temporary segmental distraction in a dog with clinical signs of DLSS.

Methods:  Distraction of the lumbosacral junction by pedicle screw-rod fixation was applied in a 5-year-old Greyhound with DLSS and evaluated by radiography, magnetic resonance imaging, and force plate analysis before and after distraction.

Results:  Safe distraction of the lumbosacral junction was demonstrated, with improvement of clinical signs after removal of the distraction device. Signal intensity of the intervertebral disc showed no changes over time. T2 value was highest directly after removal of the distraction device but decreased by 10% of the preoperative value at 9 months of follow-up. Disc height decreased (8%) immediately after removal of the distraction device, but recovered to the initial value. A decrease in the pelvic/thoracic propulsive force during pedicle screw-rod fixation and distraction was demonstrated, which slowly increased by 4% compared with the initial value.

Clinical Significance:  Temporary pedicle screw-rod fixation in combination with distraction in a dog with DLSS was safe, improved clinical signs and retained disc height at 9 months of follow-up.
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http://dx.doi.org/10.1055/s-0038-1639599DOI Listing
July 2018

Lack of consensus on optimal acetabular cup orientation because of variation in assessment methods in total hip arthroplasty: a systematic review.

Hip Int 2019 Jan 17;29(1):41-50. Epub 2018 May 17.

1 Clinical Orthopedic Research Centre - mN, Zeist, Utrecht, The Netherlands.

Introduction:: Dislocation is 1 of the main reasons for revision of total hip arthroplasty but dislocation rates have not changed in the past decades, compromising patients' well-being. Acetabular cup orientation plays a key role in implant stability and has been widely studied. This article investigates whether there is a consensus on optimal cup orientation, which is necessary when using a navigation system.

Methods:: A systematic search of the literature in the PubMed, Embase and Cochrane databases was performed (March 2017) to identify articles that investigated the direct relationship between cup orientation and dislocation, including a thorough evaluation of postoperative cup orientation assessment methods.

Results:: 28 relevant articles evaluating a direct relation between dislocation and cup orientation could not come to a consensus. The key reason is a lack of uniformity in the assessment of cup orientation. Cup orientation is assessed with different imaging modalities, different methodologies, different definitions for inclination and anteversion, several reference planes and distinct patient positions.

Conclusions:: All available studies lack uniformity in cup orientation assessment; therefore it is impossible to reach consensus on optimal cup orientation. Using navigation systems for placement of the cup is inevitably flawed when using different definitions in the preoperative planning, peroperative placement and postoperative evaluation. Further methodological development is required to assess cup orientation. Consequently, the postoperative assessment should be uniform, thus differentiating between anterior and posterior dislocation, use the same definitions for inclination and anteversion with the same reference plane and with the patient in the same position.
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http://dx.doi.org/10.1177/1120700018759306DOI Listing
January 2019

An uncemented iso-elastic monoblock acetabular component: preliminary results.

J Arthroplasty 2015 Apr 27;30(4):615-21. Epub 2014 Nov 27.

Clinical Orthopedic Research Center-midden Nederland (CORC-mN) Department of Orthopedics, Diakonessenhuis Hospital, Utrecht, The Netherlands.

Little is known about the clinical application of highly cross-linked polyethylene (HXLPE) blended with vitamin E. This study evaluates an uncemented iso-elastic monoblock cup with vitamin E blended HXLPE. 112 patients were followed up for 2years. 95.5% completed the follow-up. The mean VAS score for patient satisfaction was 8.8 and the mean Harris Hip Score was 94.2. In 7 cases initial gaps behind the cup were observed, which disappeared completely during follow-up in 6 cases. The mean femoral head penetration rate was 0.055mm/year. No adverse reactions or abnormal mechanical behavior was observed with the short term use of vitamin E blended HXLPE. This study shows the promising performance of this cup and confirms the potential of vitamin E blended HXLPE.
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http://dx.doi.org/10.1016/j.arth.2014.11.017DOI Listing
April 2015

Poor intermediate-term survival of the uncemented Optan anatomically adapted femoral component.

Acta Orthop 2014 Aug 23;85(4):363-7. Epub 2014 Jun 23.

Clinical Orthopaedic Research Center - midden Nederland (CORC-mN) , Department of Orthopaedics, Diakonessenhuis Hospital Utrecht/Zeist, Utrecht , the Netherlands .

Purpose: We evaluated the 5-year survival of the uncemented Optan anatomically adapted femoral stem, with revision for aseptic loosening as the endpoint.

Methods: Between January 2004 and March 2007, 432 total hip arthroplasties (THAs) were performed in 432 patients. After follow-up for a mean time of 5 years, the patients were evaluated using the WOMAC questionnaire and plain radiography. Patients who were unable to attend the follow-up visit were contacted by telephone to determine whether they had had any revision surgery of their THA.

Results: Within 5 years, 39 patients (9%) had died of unrelated causes and 63 patients (15%) had been lost to follow-up. Of the remaining cohort, 224 patients (68%) had full follow-up while 88 patients (27%) were evaluated with WOMAC only and 18 patients (5%) were evaluated with radiography only. The mean WOMAC score of all evaluated patients was 21 (10-100). At 5-year follow-up, there were 26 stem revisions reported (6%), 14 hips (3%) showed aseptic loosening, and 12 hips (3%) had had a periprosthetic femoral fracture. The 5-year survival to revision for any reason was 94%. Worst-case analysis yielded a 5-year survival of 79%.

Interpretation: The 5-year survival for aseptic loosening of the Optan anatomically adapted femoral component was disappointing. Radiographic evaluation showed evidence of proximal radiolucencies and distal cortical bone hypertrophy, which we attribute to insufficient proximal bone in-growth and increased load transfer at the tip of the stem. We do not recommend the use of the Optan femoral stem.
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http://dx.doi.org/10.3109/17453674.2014.934185DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4105766PMC
August 2014

Edge loading does not increase wear rates of ceramic-on-ceramic and metal-on-polyethylene articulations.

J Biomed Mater Res B Appl Biomater 2014 Nov 21;102(8):1627-38. Epub 2014 Mar 21.

Department of Orthopedics, Clinical Orthopedic Research Center (CORC-mN), Diakonessenhuis Utrecht/Zeist, Bosboomstraat 1, 3582 KE, Utrecht, The Netherlands.

The mal-positioning of total hip arthroplasty components can result in edge loading conditions. Purpose of this study was to determine if the wear rate of ceramic-on-ceramic and metal-on-polyethylene increases under edge loading conditions. The literature was reviewed to determine which of the commonly used hip bearings is the most forgiving to implant mal-orientation. Two 28-mm ceramic-on-ceramic articulations were tested in vitro: pure alumina (PAL) ceramic versus the new alumina-toughened zirconia (ATZ). Two 28-mm metal-on-polyethylene articulations were tested in vitro: conventional ultrahigh molecular weight polyethylene (UHMWPE) versus highly crosslinked polyethylene (HXLPE) stabilized with vitamin E. All bearings were tested at standard and at highest possible inclination angles. Hip simulator tests were run for five million cycles based on N = 3 tests per condition. The average wear rate of ATZ-on-ATZ is 0.024 mm(3) /Mcycles at 45° and 0.018 mm(3) /Mcycles at 65°. Wear rate of PAL-on-PAL is between 0.02 and 0.03 mm(3) /Mcycles at 45°, as well as 65°. The wear rate of UHMWPE was 31 ± 1 mm(3) /Mcycles at an inclination angle of 45° and 26 ± 1 mm(3) /Mcycles at 80°. The wear rate of vitamin E stabilized HXLPE was 5.9 ± 0.2 mm(3) /Mcycles at 45° and 5.8 ± 0.2 mm(3) /Mcycles at 80°. Edge loading does not increase the wear rate of ceramic-on-ceramic and metal-on-polyethylene articulations. The newest biomaterials showed markedly lower wear rates compared with their conventional counterparts. ATZ-on-ATZ showed the lowest wear rate of all tested pairings, but the vitamin E stabilized HXLPE seems to be the most forgiving material when it comes to implant mal-orientation.
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http://dx.doi.org/10.1002/jbm.b.33147DOI Listing
November 2014

The SNAP trial: a double blind multi-center randomized controlled trial of a silicon nitride versus a PEEK cage in transforaminal lumbar interbody fusion in patients with symptomatic degenerative lumbar disc disorders: study protocol.

BMC Musculoskelet Disord 2014 Feb 25;15:57. Epub 2014 Feb 25.

Clinical Orthopaedic Research Center-midden Nederland (CORC-mN), Department of Orthopaedics, Diakonessenhuis, Utrecht/Zeist, The Netherlands.

Background: Polyetheretherketone (PEEK) cages have been widely used in the treatment of lumbar degenerative disc disorders, and show good clinical results. Still, complications such as subsidence and migration of the cage are frequently seen. A lack of osteointegration and fibrous tissues surrounding PEEK cages are held responsible. Ceramic implants made of silicon nitride show better biocompatible and osteoconductive qualities, and therefore are expected to lower complication rates and allow for better fusion.Purpose of this study is to show that fusion with the silicon nitride cage produces non-inferior results in outcome of the Roland Morris Disability Questionnaire at all follow-up time points as compared to the same procedure with PEEK cages.

Methods/design: This study is designed as a double blind multi-center randomized controlled trial with repeated measures analysis. 100 patients (18-75 years) presenting with symptomatic lumbar degenerative disorders unresponsive to at least 6 months of conservative treatment are included. Patients will be randomly assigned to a PEEK cage or a silicon nitride cage, and will undergo a transforaminal lumbar interbody fusion with pedicle screw fixation. Primary outcome measure is the functional improvement measured by the Roland Morris Disability Questionnaire. Secondary outcome parameters are the VAS leg, VAS back, SF-36, Likert scale, neurological outcome and radiographic assessment of fusion. After 1 year the fusion rate will be measured by radiograms and CT. Follow-up will be continued for 2 years. Patients and clinical observers who will perform the follow-up visits will be blinded for type of cage used during follow-up. Analyses of radiograms and CT will be performed independently by two experienced radiologists.

Discussion: In this study a PEEK cage will be compared with a silicon nitride cage in the treatment of symptomatic degenerative lumbar disc disorders. To our knowledge, this is the first randomized controlled trial in which the silicon nitride cage is compared with the PEEK cage in patients with symptomatic degenerative lumbar disc disorders.

Trial Registration: NCT01557829.
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http://dx.doi.org/10.1186/1471-2474-15-57DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3937453PMC
February 2014

Polyetheretherketone (PEEK) cages in cervical applications: a systematic review.

Spine J 2015 Jun 27;15(6):1446-60. Epub 2013 Dec 27.

Department of Orthopaedics, University Medical Center Utrecht, Utrecht, The Netherlands.

Background Context: Polyetheretherketone (PEEK) cages have been widely used during the past decade in patients with degenerative disorders of the cervical spine. Their radiolucency and low elastic modulus make them attractive attributes for spinal fusion compared with titanium and bone graft. Still, limitations are seen such as pseudoarthrosis, subsidence, and migration of the cages. Limited evidence on the clinical outcome of PEEK cages is found in the literature other than noncomparative cohort studies with only a few randomized controlled trials.

Purpose: To assess the clinical and radiographic outcome of PEEK cages in the treatment of degenerative disc disorders and/or spondylolisthesis in the cervical spine.

Study Design: Systematic review of all randomized controlled trials and prospective and retrospective nonrandomized comparative studies with a minimum follow-up of 6 months and all noncomparative cohort studies with a long-term follow-up of more than 5 years.

Outcome Measures: The primary outcome variable was clinical performance. Secondary outcome variables consisted of radiographic scores.

Methods: The MEDLINE, EMBASE, and Cochrane Library databases were searched according to the Preferred Reporting Items of Systematic reviews and Meta-Analyses statement and Meta-analysis Of Observational Studies in Epidemiology guidelines. No conflict of interest reported. No funding received.

Results: A total of 223 studies were identified, of which 10 studies were included. These comprised two randomized controlled trials, five prospective comparative trials, and three retrospective comparative trials.

Conclusions: Minimal evidence for better clinical and radiographic outcome is found for PEEK cages compared with bone grafts in the cervical spine. No differences were found between PEEK, titanium, and carbon fiber cages. Future studies are needed to improve methodology to minimize bias. Publication of lumbar interbody fusion studies needs to be promoted because differences in clinical and/or radiographic scores are more likely to be demonstrated in this part of the spine.
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http://dx.doi.org/10.1016/j.spinee.2013.08.030DOI Listing
June 2015

Do monoblock cups improve survivorship, decrease wear, or reduce osteolysis in uncemented total hip arthroplasty?

Clin Orthop Relat Res 2013 Nov 3;471(11):3572-80. Epub 2013 Aug 3.

Clinical Orthopedic Research Center-midden Nederland (CORC-mN), Department of Orthopaedics, Diakonessenhuis Hospital, PO Box 80250, 3508 TG, Utrecht, The Netherlands,

Background: Monoblock acetabular components used in uncemented total hip arthroplasty (THA) have certain mechanical characteristics that potentially reduce acetabular osteolysis and polyethylene wear. However, the degree to which they achieve this goal is not well documented.

Questions/purposes: The purpose of this study was to use a systematic review of controlled trials to test the hypothesis that monoblock cups have superior (1) polyethylene wear rate; (2) frequency of cup migration; (3) frequency of acetabular osteolysis; and (4) frequency of aseptic loosening compared with modular components used in uncemented THA.

Methods: A systematic search was conducted in the Medline, Embase, and Cochrane electronic databases to assemble all controlled trials comparing monoblock with modular uncemented acetabular components in primary THA. Included studies were considered "best evidence" if the quality score was either ≥ 50% on the Cochrane Back Review Group checklist or ≥ 75% the Newcastle-Ottawa quality assessment scale. A total of seven publications met our inclusion criteria.

Results: Best evidence analysis showed no difference in polyethylene wear rate, the frequency of cup migration, and aseptic loosening between monoblock and modular acetabular components. No convincing evidence was found for the claim that lower frequencies of acetabular osteolysis are observed with the use of monoblock cups compared with modular uncemented cups.

Conclusions: The purported benefits of monoblock cups were not substantiated by this systematic review of controlled studies in that polyethylene wear rates and frequencies of cup failure and acetabular osteolysis were similar to those observed with modular implants. Other factors should therefore drive implant selection in cementless THA.
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http://dx.doi.org/10.1007/s11999-013-3144-yDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3792292PMC
November 2013

Excellent survivorship of the Morscher monoblock cup with a 28-mm Metasul-on-Metasul bearing at a mean of 5-year follow-up.

J Arthroplasty 2014 Feb 12;29(2):405-9. Epub 2013 Jun 12.

Clinical Orthopedic Research Center (CORC-mN), Department of Orthopedics, Diakonessenhuis Hospital Utrecht/Zeist, Utrecht, the Netherlands.

The Morscher monoblock cup is designed for optimal osteointegration and holds the potential for excellent long-term survival. The Metasul-on-Metasul bearing was introduced to eliminate wear-induced periprosthetic osteolysis. This study reviews 137 Morscher cups with a 28-mm Metasul-on-Metasul bearing used in primary THA at 5.1years (3.2-6.6) after implantation. One hundred thirty-seven cups were implanted in 119 patients. Three patients (2.2%) had died of unrelated causes, and 10 patients (8.0%) were lost to follow-up. The mean Harris Hip score was 89.8 and the mean WOMAC sum score was 18.5. No cases of acetabular osteolysis were found. The 5-year cup survival rate was 98.5%. The Morscher cup with a 28-mm Metasul-on-Metasul bearing used in uncemented THA showed no acetabular osteolysis and promising survivorship at intermediate-term follow-up.
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http://dx.doi.org/10.1016/j.arth.2013.05.005DOI Listing
February 2014

Use of fluorochrome labels in in vivo bone tissue engineering research.

Tissue Eng Part B Rev 2010 Apr;16(2):209-17

Department of Orthopaedics, University Medical Center Utrecht, Utrecht, The Netherlands.

The use of fluorochromes in bone research is a widely accepted technique that dates back to the 1950s. Several pioneers, such as Harold Frost, have thoroughly investigated the potential of fluorochrome use for the study on bone formation and bone remodeling dynamics. Since the development of bone tissue engineering, a renewed interest in the benefits of fluorochrome use was perceived. Fluorochrome use in animal models makes it possible to determine the onset time and location of osteogenesis, which are the fundamental parameters in bone tissue engineering studies. There is, however, a lack of standardized procedures for using this technique. In addition, many types of fluorochromes exist and one could be confused upon selecting the appropriate type, the appropriate concentration, the route of administration, and methods of visualization. All these variables can potentially affect the outcome during fluorescence microscopy. This work aims at providing the bone tissue engineering researcher with an overview of the history, working mechanism, and the potential pitfalls in the use of fluorochromes in animal studies. Experiments using some of the more frequently used fluorochromes are explained and illustrated.
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http://dx.doi.org/10.1089/ten.TEB.2009.0503DOI Listing
April 2010

Goat bone tissue engineering: comparing an intramuscular with a posterolateral lumbar spine location.

Tissue Eng Part A 2010 Feb;16(2):685-93

Department of Orthopaedics, University Medical Center Utrecht, Utrecht, The Netherlands.

The aim of this study was to investigate the effect of implant location on bone formation in goats using autologous bone marrow-derived stromal cells in porous calcium phosphate scaffolds. Intramuscular locations were compared to posterolateral spine fusion locations in eight goats. As scaffolds, we used biphasic calcium phosphate porous blocks of 5 x 5 x 5 mm. Cell-seeded implants were compared to empty controls. Bone marrow-derived stromal cells were seeded at 8 million cells per cm(3) scaffold and cultured for 1 week. The follow-up time was 12 weeks. Fluorochromes were administered intravenously at 4, 6, and 8 weeks. Ectopic implants showed 21 +/- 3.6% bone formation for the cell seeded and 2.0 +/- 3.0% for the controls (p < 0.001). Paraspinal implants, however, showed 0.10 +/- 0.13% in the cell seeded compared to 0.023 +/- 0.027% in the control group (p = 0.09). A benefit of the cells was only found in the area closest to the paraspinal muscles (p < 0.01). Bone formation in the control samples was of later onset compared to the cell-seeded implants. In conclusion, cell-based bone tissue engineering in an ectopic environment was clearly effective. Similar constructs implanted in a posterolateral spine fusion location hardly showed any effect.
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http://dx.doi.org/10.1089/ten.TEA.2009.0073DOI Listing
February 2010

Relating cell proliferation to in vivo bone formation in porous Ca/P scaffolds.

J Biomed Mater Res A 2010 Jan;92(1):303-10

Department of Orthopaedics, University Medical Center Utrecht, 3508 GA Utrecht, The Netherlands.

Most current methods for cell monitoring on 3D porous scaffolds involve end-stage investigation of scaffolds. Repeated measurements on scaffolds, without disturbing cell vitality and proliferation, are needed to relate in vitro to in vivo data. Alamar Blue was used for this purpose. Two different Ca/P scaffolds were studied, using rat BMSCs with three different seeding densities [2.5 x 10(4) (SD1), 2.5 x 10(5) (SD2), 2.5 x 10(6) (SD3) cells]. Alamar Blue readings were done on days 1, 3, 5 and 7. After 7 days all 96 scaffolds (n = 16) were implanted in 16 mice for 4 weeks. Bone histomorphometry was performed. For both scaffolds, seeding efficiencies were highest with SD1 and SD2, cell proliferation was optimal in SD1, whereas SD3 resulted in an initial drop in vital cell number in the first 3 days. In vivo, upscaling from SD1 to SD2 lead to significantly more bone contact% in both scaffolds. Alamar Blue was shown to be a valuable tool in relating in vitro to in vivo data. Cell proliferation may differ depending on seeding density and scaffold type used. Seeding more cells may not necessarily result in more in vivo bone contact%.
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http://dx.doi.org/10.1002/jbm.a.32380DOI Listing
January 2010