Publications by authors named "Lars F H Theyse"

14 Publications

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Comparison of Single versus Double Lateral Plating in Treatment of Feline Ilial Fractures Using Veterinary Cuttable Plates.

Vet Comp Orthop Traumatol 2021 Jun 3. Epub 2021 Jun 3.

Department of Clinical Sciences, Faculty of Veterinary Medicine, Utrecht, The Netherlands.

Objective:  The aim of this study was to compare the frequency of implant failure and the extent of pelvic canal narrowing associated with the fixation of ilial fractures in cats with a single veterinary cuttable plate (SLP) or double veterinary cuttable plates (DLP) applied to the lateral surface of the ilium.

Study Design:  Radiographic evaluation of feline ilial fractures plated laterally using SLP or DLP. Pelvic canal narrowing directly postoperatively and at 6 weeks follow-up was objectively measured using the sacral index (SI). Radiographs were evaluated for implant failure and fracture healing.

Results:  Seventy-seven cats satisfied the inclusion criteria. Twenty-nine fractures were treated with a SLP and 48 with DLP. Implant failure occurred significantly more ( = 0.001) in the SLP group (14/29) compared with the DLP group (6/48). Follow-up SI was significantly different between the two groups ( = 0.048, SLP median: 1.0 range: 0.83-2.4, DLP median: 0.98; range: 0.76-1.45). Median change in SI was -0.04 (range: -1.4-0.05) in the SLP group and 0.0 (range: -0.23-0.23) in the DLP group. This difference was significantly different ( = 0.031).

Conclusion:  DLP leads to significantly less implant failure and significantly less pelvic canal narrowing compared with SLP. This difference in pelvic canal narrowing was small and the clinical relevance remains unclear.
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http://dx.doi.org/10.1055/s-0041-1729624DOI Listing
June 2021

Proximodistal and caudocranial position of the insertion of the patellar ligament on the tibial tuberosity and patellar ligament length of normal stifles and stifles with grade II medial patellar luxation in small-breed dogs.

Vet Surg 2021 May 20. Epub 2021 May 20.

Department for Small Animals, Soft Tissue & Orthopedic Surgery Service, College of Veterinary Medicine, University of Leipzig, Leipzig, Germany.

Objective: To assess the role of the proximodistal and caudocranial relative position of the patellar ligament insertion on the tibia and patellar ligament length-to-patellar length ratio (PLL:PL) in small-breed dogs with and without grade II medial patellar luxation (MPL).

Study Design: Retrospective study.

Sample Population: Dogs weighing ≤15 kg, including 43 stifles with MPL and 34 control stifles.

Methods: The proximodistal and caudocranial relative position of the patellar ligament insertion was determined as a ratio using the vertical (VTT) and horizontal distance (HTT) between the tibial tuberosity insertion and the tibial plateau divided by the tibial plateau length (TPL). In addition, PLL:PL and tibial plateau angle (TPA) were determined.

Results: The VTT:TPL ratio was lower in affected stifles (95% CI: 0.86-0.94) than in the control group (0.93-1.01; p = .01). No other difference was identified between affected and normal stifles.

Conclusion: The only difference identified in this study consisted of a more proximal position of the patellar ligament insertion in the stifles of small-breed dogs with grade II MPL.

Clinical Significance: The more proximal position of the patellar ligament insertion will result in a more proximal position of the patella in the trochlear groove and may contribute to the development of MPL. Potentially, this will also affect the risk of recurrence of MPL after surgical treatment.
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http://dx.doi.org/10.1111/vsu.13661DOI Listing
May 2021

Treatment of deep corneal ulcers with porcine small intestinal submusosa using a modified surgical technique in dogs.

Clin Case Rep 2021 Feb 16;9(2):812-817. Epub 2020 Dec 16.

Department of Small Animals University of Leipzig Leipzig Germany.

Treatment of deep corneal ulcers using small intestinal submucosa (SIS) without corneal sutures in combination with a third eyelid flap seems a promising technical modification. Advantages are a reduction in surgery time and no additional damage of healthy corneal tissue.
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http://dx.doi.org/10.1002/ccr3.3661DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7869326PMC
February 2021

CORR Insights®: Percutaneous CO2 Treatment Accelerates Bone Generation During Distraction Osteogenesis in Rabbits.

Authors:
Lars F H Theyse

Clin Orthop Relat Res 2020 08;478(8):1936-1938

L. F. H. Theyse, College of Veterinary Medicine, University of Leipzig, Department for Small Animals, Soft Tissue and Orthopaedic Surgery Service, Leipzig, Germany.

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http://dx.doi.org/10.1097/CORR.0000000000001368DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7371037PMC
August 2020

Orthopedic surgery increases atherosclerotic lesions and necrotic core area in ApoE-/- mice.

Atherosclerosis 2016 12 28;255:164-170. Epub 2016 Oct 28.

Institute for Cardiovascular Research (ICaR-VU), VU University Medical Center, Amsterdam, The Netherlands; Department of Internal Medicine, VU University Medical Center, Amsterdam, The Netherlands.

Background And Aims: Observational studies show a peak incidence of cardiovascular events after major surgery. For example, the risk of myocardial infarction increases 25-fold early after hip replacement. The acuteness of this increased risk suggests abrupt enhancement in plaque vulnerability, which may be related to intra-plaque inflammation, thinner fibrous cap and/or necrotic core expansion. We hypothesized that acute systemic inflammation following major orthopedic surgery induces such changes.

Methods: ApoE mice were fed a western diet for 10 weeks. Thereafter, half the mice underwent mid-shaft femur osteotomy followed by realignment with an intramedullary K-wire, to mimic major orthopedic surgery. Mice were sacrificed 5 or 15 days post-surgery (n = 22) or post-saline injection (n = 13). Serum amyloid A (SAA) was measured as a marker of systemic inflammation. Paraffin embedded slides of the aortic root were stained to measure total plaque area and to quantify fibrosis, calcification, necrotic core, and inflammatory cells.

Results: Surgery mice showed a pronounced elevation of serum amyloid A (SAA) and developed increased plaque and necrotic core area already at 5 days, which reached significance at 15 days (p = 0.019; p = 0.004 for plaque and necrotic core, respectively). Macrophage and lymphocyte density significantly decreased in the surgery group compared to the control group at 15 days (p = 0.037; p = 0.024, respectively). The density of neutrophils and mast cells remained unchanged.

Conclusions: Major orthopedic surgery in ApoE-/- mice triggers a systemic inflammatory response. Atherosclerotic plaque area is enlarged after surgery mainly due to an increase of the necrotic core. The role of intra-plaque inflammation in this response to surgical injury remains to be fully elucidated.
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http://dx.doi.org/10.1016/j.atherosclerosis.2016.07.909DOI Listing
December 2016

Radiographic, computed tomographic, and arthroscopic findings in labrador retrievers with medial coronoid disease.

Vet Surg 2015 May 16;44(4):511-20. Epub 2014 Oct 16.

Division of Diagnostic Imaging, Faculty of Veterinary Medicine, Utrecht University, Utrecht, The Netherlands.

Objective: To describe the radiographic, computed tomographic (CT), and arthroscopic findings in different age groups of Labrador Retrievers diagnosed with medial coronoid disease (MCD), and to compare the ulnar subtrochlear sclerosis (STS) observed on radiographs with the ratio between the mean attenuation of the ulnar subtrochlear bone and the mean attenuation of the cortical bone measured on CT.

Study Design: Prospective clinical study.

Animals: Dogs (n = 31; 31 elbow joints) and 6 healthy Labrador Retrievers (6 elbow joints).

Methods: Radiographic, CT, and intraoperative arthroscopic images (2008-2012) were evaluated. Statistical analysis was performed for the descriptive study to evaluate the difference in findings between age groups and to investigate the correlation between radiographic and CT evaluated ulnar STS.

Results: Ulnar STS (87.6%) was the most common radiographic findings in dogs ≤12 months and blurring of the cranial edge of the medial coronoid process (MCP; 66.7%) was the most common radiographic findings in dogs >12 months. MCP fragmentation was the most common CT finding in both age groups (93.8% [≤12 months]; 66.7% [>12 months]). A displaced fragment (68.8%) was the most common arthroscopic finding in dogs ≤12 months whereas osteochondromalacia (53.3%) was the most common finding in dogs >12 months. Sensitivity of radiography in detecting MCD was 93.8% (≤12 months) and 73.3% (>12 months) and for CT was 93.8% (≤12 months) and 66.7% (>12 months). Radiographic evaluated ulnar STS was strongly correlated with CT evaluated ulnar STS.

Conclusion: Wide ranges of radiographic, CT, and arthroscopic findings in Labrador Retrievers diagnosed with medial coronoid disease were identified.
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http://dx.doi.org/10.1111/j.1532-950X.2014.12291.xDOI Listing
May 2015

Decellularized cartilage-derived matrix as substrate for endochondral bone regeneration.

Tissue Eng Part A 2015 Feb 20;21(3-4):694-703. Epub 2014 Nov 20.

1 Department of Orthopedics, University Medical Center Utrecht , Utrecht, The Netherlands .

Following an endochondral approach to bone regeneration, multipotent stromal cells (MSCs) can be cultured on a scaffold to create a cartilaginous callus that is subsequently remodeled into bone. An attractive scaffold material for cartilage regeneration that has recently regained attention is decellularized cartilage-derived matrix (CDM). Since this material has shown potential for cartilage regeneration, we hypothesized that CDM could be a potent material for endochondral bone regeneration. In addition, since decellularized matrices are known to harbor bioactive cues for tissue formation, we evaluated the need for seeded MSCs in CDM scaffolds. In this study, ectopic bone formation in rats was evaluated for CDM scaffolds seeded with human MSCs and compared with unseeded controls. The MSC-seeded samples were preconditioned in chondrogenic medium for 37 days. After 8 weeks of subcutaneous implantation, the extent of mineralization was significantly higher in the MSC-seeded constructs versus unseeded controls. The mineralized areas corresponded to bone formation with bone marrow cavities. In addition, rat-specific bone formation was confirmed by collagen type I immunohistochemistry. Finally, fluorochrome incorporation at 3 and 6 weeks revealed that the bone formation had an inwardly directed progression. Taken together, our results show that decellularized CDM is a promising biomaterial for endochondral bone regeneration when combined with MSCs at ectopic locations. Modification of current decellularization protocols may lead to enhanced functionality of CDM scaffolds, potentially offering the prospect of generation of cell-free off-the-shelf bone regenerative substitutes.
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http://dx.doi.org/10.1089/ten.TEA.2014.0117DOI Listing
February 2015

Programmatic assessment of competency-based workplace learning: when theory meets practice.

BMC Med Educ 2013 Sep 11;13:123. Epub 2013 Sep 11.

Quality Improvement in Veterinary Education, Faculty of Veterinary Medicine, Utrecht University, Utrecht, The Netherlands.

Background: In competency-based medical education emphasis has shifted towards outcomes, capabilities, and learner-centeredness. Together with a focus on sustained evidence of professional competence this calls for new methods of teaching and assessment. Recently, medical educators advocated the use of a holistic, programmatic approach towards assessment. Besides maximum facilitation of learning it should improve the validity and reliability of measurements and documentation of competence development. We explored how, in a competency-based curriculum, current theories on programmatic assessment interacted with educational practice.

Methods: In a development study including evaluation, we investigated the implementation of a theory-based programme of assessment. Between April 2011 and May 2012 quantitative evaluation data were collected and used to guide group interviews that explored the experiences of students and clinical supervisors with the assessment programme. We coded the transcripts and emerging topics were organised into a list of lessons learned.

Results: The programme mainly focuses on the integration of learning and assessment by motivating and supporting students to seek and accumulate feedback. The assessment instruments were aligned to cover predefined competencies to enable aggregation of information in a structured and meaningful way. Assessments that were designed as formative learning experiences were increasingly perceived as summative by students. Peer feedback was experienced as a valuable method for formative feedback. Social interaction and external guidance seemed to be of crucial importance to scaffold self-directed learning. Aggregating data from individual assessments into a holistic portfolio judgement required expertise and extensive training and supervision of judges.

Conclusions: A programme of assessment with low-stakes assessments providing simultaneously formative feedback and input for summative decisions proved not easy to implement. Careful preparation and guidance of the implementation process was crucial. Assessment for learning requires meaningful feedback with each assessment. Special attention should be paid to the quality of feedback at individual assessment moments. Comprehensive attention for faculty development and training for students is essential for the successful implementation of an assessment programme.
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http://dx.doi.org/10.1186/1472-6920-13-123DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3851012PMC
September 2013

Effects of observer on the diagnostic accuracy of low-field MRI for detecting canine meniscal tears.

Vet Radiol Ultrasound 2012 Nov-Dec;53(6):628-35. Epub 2012 Aug 16.

Department of Small Animal Medicine, University of Leipzig, Germany.

Low-field MRI (lfMRI) has become increasingly accepted as a method for diagnosing canine meniscal tears in clinical practice. However, observer effects on diagnostic accuracy have not been previously reported. In this study, 50 consecutive stifle joints with clinical and radiologic evidence of cranial cruciate ligament insufficiency were investigated by lfMRI and arthroscopy. Fifteen observers who had varying levels of experience and who were unaware of arthroscopic findings independently reviewed lfMRI studies and recorded whether lateral and medial meniscal tears were present. Diagnostic accuracy (sensitivity, specificity, positive (PPV) and negative predictive value (NPV)) was determined for each observer and median values were calculated for all observers, using arthroscopy as the reference standard. Interrater agreement was determined based on intraclass correlation coefficient (ICC) analysis. Observer level of experience was compared with diagnostic sensitivity and specificity using correlation analysis. Based on pooled data for all observers, median sensitivity, specificity, PPV, and NPV for lfMRI diagnosis of lateral meniscal tears were 0.00, 0.94, 0.05, and 0.94, respectively. Median sensitivity, specificity, PPV, and NPV for medial meniscal tears were 0.74, 0.89, 0.83, and 0.79, respectively. Interrater agreement for all menisci was fair (0.51). Menisci were less consistently scored as having no tears (ICC = 0.13) than those scored as having tears (ICC = 0.50). No significant correlations between observer experience and diagnostic sensitivity/specificity were identified. Findings indicated that the accuracy of lfMRI for diagnosing canine meniscal tears was poor to fair and observer-dependent. Future studies are needed to develop standardized and widely accepted lfMRI criteria for diagnosing meniscal tears.
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http://dx.doi.org/10.1111/j.1740-8261.2012.01967.xDOI Listing
February 2013

A differential effect of bone morphogenetic protein-2 and vascular endothelial growth factor release timing on osteogenesis at ectopic and orthotopic sites in a large-animal model.

Tissue Eng Part A 2012 Oct 12;18(19-20):2052-62. Epub 2012 Sep 12.

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

In bone tissue engineering, growth factors are widely used. Bone morphogenetic proteins (BMPs) and vascular endothelial growth factor (VEGF) are the most well-known regulators of osteogenesis and angiogenesis. We investigated whether the timing of dual release of VEGF and BMP-2 influences the amount of bone formation in a large-animal model. Poly(lactic-co-glycolic acid) (PLGA) microparticles (MPs) were loaded with BMP-2 or VEGF to create sustained-release profiles, and rapidly degrading gelatin was loaded with either growth factor for fast-release profiles. To study in vivo osteogenicity, the two delivery vehicles were combined with biphasic calcium phosphate (BCP) scaffolds and implanted in 10 Beagle dogs for 9 weeks, at both ectopic (paraspinal muscles) and orthotopic sites (critical-size ulnar defect). The 9 ectopic groups contained combined or single BMP/VEGF dosage, in sustained- or fast-release profiles. In the ulnae of 8 dogs, fast VEGF and sustained BMP-2 were applied to one leg, and the other received the opposite release profiles. The two remaining dogs received bilateral control scaffolds. Bone growth dynamics was analyzed by fluorochrome injection at weeks 3, 5, and 7. Postoperative and posteuthanization X-rays of the ulnar implants were taken. After 9 weeks of implantation, bone quantity and bone growth dynamics were studied by histology, histomorphometry, and fluorescence microscopy. The release of the growth factors resulted in both enhanced orthotopic and ectopic bone formation. Bone formation started before 3 weeks and continued beyond 7 weeks. The ectopic BMP-2 fast groups showed significantly more bone compared to sustained release, independent of the VEGF profile. The ulna implants revealed no significant differences in the amount of bone formed. This study shows that timing of BMP-2 release largely determines speed and amount of ectopic bone formation independent of VEGF release. Furthermore, at the orthotopic site, no significant effect on bone formation was found from a timed release of growth factors, implicating that timed-release effects are location dependent.
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http://dx.doi.org/10.1089/ten.TEA.2011.0560DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3463278PMC
October 2012

Comparison of the effects of firocoxib, carprofen and vedaprofen in a sodium urate crystal induced synovitis model of arthritis in dogs.

Res Vet Sci 2008 Feb 3;84(1):74-9. Epub 2007 Apr 3.

Department of Clinical Sciences of Companion Animals, Faculty of Veterinary Medicine, P.O. Box 80.154, 3508 TD Utrecht, The Netherlands.

A randomized, placebo-controlled, four-period cross-over laboratory study involving eight dogs was conducted to confirm the effective analgesic dose of firocoxib, a selective COX-2 inhibitor, in a synovitis model of arthritis. Firocoxib was compared to vedaprofen and carprofen, and the effect, defined as a change in weight bearing measured via peak ground reaction, was evaluated at treatment dose levels. A lameness score on a five point scale was also assigned to the affected limb. Peak vertical ground reaction force was considered to be the most relevant measurement in this study. The firocoxib treatment group performed significantly better than placebo at the 3 h post-treatment time point and significantly better than placebo and carprofen at the 7 h post-treatment time point. Improvement in lameness score was also significantly better in the dogs treated with firocoxib than placebo and carprofen at both the 3 and 7 h post-treatment time points.
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http://dx.doi.org/10.1016/j.rvsc.2007.02.005DOI Listing
February 2008

Expression of osteotropic growth factors and growth hormone receptor in a canine distraction osteogenesis model.

J Bone Miner Metab 2006 ;24(4):266-73

Department of Clinical Sciences of Companion Animals, Faculty of Veterinary Medicine, Utrecht University, P.O. Box 80.154, NL-3508, TD, Utrecht, The Netherlands.

Osteotropic growth factors play an important role in bone metabolism. Nevertheless, knowledge about their expression in relation to distraction osteogenesis remains limited. The aim of the present study was to determine the expression of growth hormone (GH), growth hormone receptor (GHR), insulin-like growth factor I (IGF-I), insulin-like growth factor II (IGF-II), and bone morphogenetic protein 2 (BMP-2) in distraction-induced bone regeneration. Expression of these factors was assessed during the consolidation phase, comparing distraction osteogenesis with osteotomy-induced bone formation. Real-time PCR was performed as a semiquantitative measurement of mRNA, and the relative expression levels of these factors were determined. In addition, plasma GH profiles and plasma concentrations of IGF-I, IGF-II, and insulin-like growth factor-binding protein 4 and -6 (IGFBP-4 and -6) were measured to assess their potential systemic role during bone formation. Expression of GHR, IGF-I, and BMP-2 had significantly increased in comparison with the expression of these factors in mature bone. Expression of GHR was significantly higher in distraction-induced bone regenerate than in osteotomy-induced bone. No significant differences were found for the expression of IGF-I and BMP-2 between distraction and osteotomy. Plasma concentrations of GH, IGF-I, IGF-II, IGFBP-4, and IGFBP-6 did not demonstrate any significant differences between treatment groups and controls. Upregulation of GHR expression in distraction osteogenesis may enhance sensitivity to endogenous systemic GH and thus promote consolidation of the regenerated bone. Changes in the systemic osteotropic growth factors GH, IGF-I, IGF-II, IGFBP-4, and IGFBP-6 do not seem to be of importance during distraction osteogenesis.
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http://dx.doi.org/10.1007/s00774-006-0683-2DOI Listing
September 2006

The efficacy of the bone markers osteocalcin and the carboxyterminal cross-linked telopeptide of type-I collagen in evaluating osteogenesis in a canine crural lengthening model.

Vet J 2006 May;171(3):525-31

Department of Clinical Sciences of Companion Animals, Faculty of Veterinary Medicine, Utrecht University, Utrecht, The Netherlands.

The aim of the present study was to determine the efficacy of the bone markers osteocalcin (OC) and carboxyterminal cross-linked telopeptide of type-I collagen (ICTP) in evaluating new bone formation in the dog, using commercially available immunoassay kits. Dogs were randomly divided into three groups and a circular external skeletal fixation system (CESF) was mounted on the tibia. In the first group a distraction osteogenesis procedure of the crus was performed. The second group received an osteotomy without crural lengthening, whereas the third group served as a sham-operated control. Bone formation was assessed using densitometric image analysis of crural radiographs. Despite significant differences in the amount of newly formed bone, this finding was not reflected in the plasma levels of OC and ICTP. In conclusion, OC and ICTP were not efficacious as markers of bone formation and resorption during osteogenesis in this canine model.
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http://dx.doi.org/10.1016/j.tvjl.2005.02.001DOI Listing
May 2006

Prognostic factors in treating antebrachial growth deformities with a lengthening procedure using a circular external skeletal fixation system in dogs.

Vet Surg 2005 Sep-Oct;34(5):424-35

Department of Clinical Sciences of Companion Animals, Division of Orthopedics, Faculty of Veterinary Medicine, Utrecht University, The Netherlands.

Objective: To evaluate treatment of antebrachial growth deformities (AGD) with a lengthening procedure using a circular external skeletal fixation (CESF) system and to determine prognostic factors.

Study Design: Prospective clinical study.

Animals: Thirty-four dogs with unilateral AGD.

Methods: Length deficits, angular and rotational deformities, elbow incongruity (EI), osteoarthritis (OA) of the elbow and carpal joint, function, and cosmesis were determined before and after a CESF lengthening procedure.

Results: On admission, EI (21 dogs; 62%), OA of the elbow joint (17 dogs; 50%), carpal OA (12 dogs; 35%), and concomitant elbow and carpal OA (5 dogs; 7%) were common findings. Treatment significantly improved function (normal, 20 dogs; 60%) and cosmesis (normal, 22 dogs; 65%). Angular and rotational deformities were almost completely corrected with small remaining length deficits. Elbow and carpal OA increased significantly during the follow-up period. Significant correlations were demonstrated between initial elbow OA and final function (R=0.42, P=.02), initial function and final function (R=0.41, P=.02), and initial ulnar and radial deficit and final cosmesis (R=0.58, P=.0001 and R=0.45, P=.008).

Conclusions: Treatment of AGD by a CESF lengthening procedure was successful despite small remaining length deficits. Initial elbow OA, function, and ulnar and radial length deficits are prognostic factors in the treatment of AGD.

Clinical Relevance: Initial elbow OA and initial function are prognostic factors in predicting the functional outcome of treatment of AGD with a CESF lengthening procedure in the dog.
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http://dx.doi.org/10.1111/j.1532-950X.2005.00064.xDOI Listing
December 2005