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Aspenberg, Per
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Publications (10 of 207) Show all publications
Schilcher, J., Bernhardsson, M. & Aspenberg, P. (2019). Chronic anterior tibial stress fractures in athletes: No crack but intense remodelling. Scandinavian Journal of Medicine and Science in Sports
Open this publication in new window or tab >>Chronic anterior tibial stress fractures in athletes: No crack but intense remodelling
2019 (English)In: Scandinavian Journal of Medicine and Science in Sports, ISSN 0905-7188, E-ISSN 1600-0838Article in journal (Refereed) Epub ahead of print
Abstract [en]

PURPOSE: Delayed healing of anterior tibial stress fractures in athletes is related to high tensional forces acting across a putative fracture gap. These forces lead to crack propagation and create strains that exceed tissue differentiation thresholds for new bone to form in the gap. The "dreaded black line" is a radiographic hallmark sign of stress fractures considered to represent a transverse fracture gap. However, whether a fracture gap truly exists at the microscopic level remains unclear. The aim of this study was to describe the area of the "dreaded black line" microscopically and to identify signs of delayed healing.

METHODS: Between 2011 and 2016 we included seven athletes with chronic anterior mid-shaft tibial stress fractures. The fracture site was excised as a cylindrical biopsy. The biopsy was evaluated with micro-CT and histology. The formation of new bone in the defect was evaluated radiographically.

RESULTS: The "dreaded black line" seen on preoperative radiographs in all patients could not be seen on the microscopic level. Instead, the area of the putative crack showed widened resorption cavities, lined with active osteoblasts, and surrounded by immature bone. This area of intense remodelling seemed to create a false impression of a fracture line on radiographs. Complete cortical continuity was restored at the biopsy site at median eight months (range six to 13 months).

CONCLUSION: Tibial stress fractures in athletes normally show no fracture defect, but a region of increased remodelling. The healing process is already ongoing but seems mechanically insufficient. 

Place, publisher, year, edition, pages
John Wiley & Sons, 2019
Keywords
Stress fracture, fracture healing, histology, tibia
National Category
Orthopaedics
Identifiers
urn:nbn:se:liu:diva-157071 (URN)10.1111/sms.13466 (DOI)31102562 (PubMedID)
Funder
Region ÖstergötlandSwedish Research CouncilSwedish National Centre for Research in Sports
Available from: 2019-05-27 Created: 2019-05-27 Last updated: 2019-05-27
Bernhardsson, M., Dietrich, F., Tätting, L., Eliasson, P. & Aspenberg, P. (2019). Depletion of cytotoxic (CD8+) T cells impairs implant fixation in rat cancellous bone. Journal of Orthopaedic Research, 37(4), 805-811
Open this publication in new window or tab >>Depletion of cytotoxic (CD8+) T cells impairs implant fixation in rat cancellous bone
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2019 (English)In: Journal of Orthopaedic Research, ISSN 0736-0266, E-ISSN 1554-527X, Vol. 37, no 4, p. 805-811Article in journal (Refereed) Published
Abstract [en]

As cytotoxic (CD8(+)) T cells seem to impair shaft fracture healing, we hypothesized that depletion of CD8(+) cells would instead improve healing of cancellous bone. Additionally, we also tested if CD8-depletion would influence the healing of ruptured Achilles tendons. Rats received a single injection of either anti-CD8 antibodies or saline and put through surgery 24 h later. Three different surgical interventions were performed as follows: (1) a drill hole in the proximal tibia with microCT (BV/TV) to assess bone formation; (2) a screw in the proximal tibia with mechanical evaluation (pull-out force) to assess fracture healing; (3) Achilles tendon transection with mechanical evaluation (force-at-failure) to assess tendon healing. Furthermore, CD8-depletion was confirmed with flow cytometry on peripheral blood. Flow cytometric analysis confirmed depletion of CD8(+) cells (p amp;lt; 0.001). Contrary to our hypothesis, depletion of CD8(+) cells reduced the implant pull-out force by 19% (p amp;lt; 0.05) and stiffness by 34% (p amp;lt; 0.01), although the bone formation in the drill holes was the same as in the controls. Tendon healing was unaffected by CD8-depletion. Our results suggest that CD8(+) cells have an important part in cancellous bone healing.

Place, publisher, year, edition, pages
John Wiley & Sons, 2019
Keywords
bone healing; cancellous; tendon healing; cytotoxic T cells; CD8 depletion
National Category
Orthopaedics
Identifiers
urn:nbn:se:liu:diva-157559 (URN)10.1002/jor.24246 (DOI)000467082100001 ()30737834 (PubMedID)2-s2.0-85062344231 (Scopus ID)
Note

Funding Agencies|Swedish Research Council [2031-47-5]; AFA insurance company EU 159 7th framework program [FP7/2007-2013, 279239]; Linkoping 160 University

Available from: 2019-06-22 Created: 2019-06-22 Last updated: 2019-06-25Bibliographically approved
Abtahi, J., Henefalk, G. & Aspenberg, P. (2019). Impact of a zoledronate coating on early post-surgical implant stability and marginal bone resorption in the maxilla-A split-mouth randomized clinical trial.. Clinical Oral Implants Research, 30(1), 49-58
Open this publication in new window or tab >>Impact of a zoledronate coating on early post-surgical implant stability and marginal bone resorption in the maxilla-A split-mouth randomized clinical trial.
2019 (English)In: Clinical Oral Implants Research, ISSN 0905-7161, E-ISSN 1600-0501, Vol. 30, no 1, p. 49-58Article in journal (Refereed) Published
Abstract [en]

OBJECTIVES: The objective of this clinical study was to evaluate the effect of a bisphosphonate coating on a titanium implant on the implant stability quotient (ISQ) and the radiographic marginal bone levels at implants during early healing (2-8 weeks).

MATERIALS AND METHODS: In a randomized double-blind trial with internal controls, 16 patients received a dental implant coated with zoledronate and one uncoated implant as a control. The coated and uncoated implants which were visually indistinguishable were bone level titanium implants with a moderately rough surface and a microthreaded neck. ISQ values were obtained at insertion and at 2, 4, 6, and 8 weeks. Radiographs were obtained at insertion and at 8 weeks. The primary outcome was the difference in ISQ values between the coated implants and the control implants at 4 and 6 weeks, corrected for insertion values. The secondary outcome was loss of marginal bone level from insertion to 8 weeks.

RESULTS: Implant stability quotient values remained largely constant over the 8 weeks, and there was no significant difference between coated and uncoated implants at any time point. There was 0.12 (SD 0.10) mm marginal bone loss at the control implants and 0.04 (SD 0.08) mm at the coated implants. The difference was 0.17 mm; SD 0.14; p < 0.006). On blind qualitative scoring, 13 of the 15 control implants and two of 15 coated implants showed small marginal bone defects (p = 0.003).

CONCLUSIONS: There were no statistically significant differences observed in ISQ values between the coated and uncoated implants during the early healing. There was less marginal bone loss at the coated implants.

Place, publisher, year, edition, pages
John Wiley & Sons, 2019
Keywords
dental implant, fibrinogen, maxilla, radiography
National Category
Orthopaedics
Identifiers
urn:nbn:se:liu:diva-153634 (URN)10.1111/clr.13391 (DOI)000456748800004 ()30565741 (PubMedID)
Available from: 2019-01-06 Created: 2019-01-06 Last updated: 2019-02-27
Aspenberg, P., Michaëlsson, K., Rydholm, A. & Svensson, O. (2018). Artrosskolan: evidensen måste stärkas. Läkartidningen, 115
Open this publication in new window or tab >>Artrosskolan: evidensen måste stärkas
2018 (English)In: Läkartidningen, ISSN 0023-7205, E-ISSN 1652-7518, Vol. 115Article in journal, Editorial material (Other academic) Published
Place, publisher, year, edition, pages
Läkartidningen Förlag AB, 2018
National Category
Orthopaedics
Identifiers
urn:nbn:se:liu:diva-152530 (URN)29381178 (PubMedID)
Available from: 2019-03-28 Created: 2019-03-28 Last updated: 2019-04-02Bibliographically approved
Aspenberg, P. (2017). Apropå! En arrogant organisation. Läkartidningen, 114
Open this publication in new window or tab >>Apropå! En arrogant organisation
2017 (Swedish)In: Läkartidningen, ISSN 0023-7205, E-ISSN 1652-7518, Vol. 114Article in journal, Editorial material (Other academic) Published
Abstract [en]

n/a

Place, publisher, year, edition, pages
Stockholm, Sweden: Läkartidningen Förlag AB, 2017
National Category
Health Sciences Clinical Medicine
Identifiers
urn:nbn:se:liu:diva-146347 (URN)29292934 (PubMedID)
Available from: 2018-04-07 Created: 2018-04-07 Last updated: 2019-02-01Bibliographically approved
Aspenberg, P. (2017). Beslut att operera kopplat till ortopeders attityder till kirurgi. Läkartidningen, 114(41)
Open this publication in new window or tab >>Beslut att operera kopplat till ortopeders attityder till kirurgi
2017 (English)In: Läkartidningen, ISSN 0023-7205, E-ISSN 1652-7518, Vol. 114, no 41Article in journal, Editorial material (Refereed) Published
Abstract [en]

[No abstract available]

Place, publisher, year, edition, pages
Läkartidningen Förlag, 2017
National Category
Orthopaedics
Identifiers
urn:nbn:se:liu:diva-147019 (URN)2-s2.0-85031295393 (Scopus ID)
Available from: 2018-04-09 Created: 2018-04-09 Last updated: 2018-04-24
Blomgran, P., Blomgran, R., Ernerudh, J. & Aspenberg, P. (2017). Cox-2 inhibition and the composition of inflammatory cell populations during early and mid-time tendon healing. Muscles, ligaments and Tendons journal, 7(2), 223-229
Open this publication in new window or tab >>Cox-2 inhibition and the composition of inflammatory cell populations during early and mid-time tendon healing
2017 (English)In: Muscles, ligaments and Tendons journal, ISSN 2240-4554, Vol. 7, no 2, p. 223-229Article in journal (Refereed) Published
Abstract [en]

Background: During early tendon healing, the cells within the regenerating tissue are, to a large part, inflammatory leukocytes (CD45+). In a rat Achilles tendon healing model, the inflammation resolves between 5 and 10 days. In the same model, Cox inhibitors (NSAIDs) impair healing when given during the first 5 days, but have a positive effect if given later. We tested the hypothesis that a Cox inhibitor would exert these effects by influencing inflammation, and thereby the composition of the inflammatory cell subpopulations.Methods: Achilles tendon transection was performed in 44 animals. Animals were randomized to either parecoxib or saline injections. Healing was evaluated by mechanical testing day 7 after surgery and by flow cytometry day 3 and 10.Results: Cross-sectional area, peak force and stiffness were reduced by parecoxib 31, 33, and 25% respectively (p=0.005, p=0.002, and p=0.005). By flow cytometry, there was a strong effect of time (p<0.001) on virtually all inflammatory cell subpopulations (CD45, CD11b, CD68, CCR7, CD163, CD206, CD3, CD4), but no significant effect of parecoxib at any time point.Conclusion: The results suggest that the negative effects of Cox inhibitors on tendon healing might be exerted mainly via mechanisms not directly related to inflammatory cells.

Place, publisher, year, edition, pages
Rome, Italy: CIC Edizioni Internazionali, 2017
Keywords
tendon healing; NSAID; inflammation; rat model; flow cytometry
National Category
Pharmacology and Toxicology
Identifiers
urn:nbn:se:liu:diva-142352 (URN)10.11138/mltj/2017.7.2.223 (DOI)
Available from: 2017-10-27 Created: 2017-10-27 Last updated: 2018-04-17
Sandberg, O., Bernhardsson, M. & Aspenberg, P. (2017). Earlier effect of alendronate in mouse metaphyseal versus diaphyseal bone healing. Journal of Orthopaedic Research, 35(4), 793-799
Open this publication in new window or tab >>Earlier effect of alendronate in mouse metaphyseal versus diaphyseal bone healing
2017 (English)In: Journal of Orthopaedic Research, ISSN 0736-0266, E-ISSN 1554-527X, Vol. 35, no 4, p. 793-799Article in journal (Refereed) Published
Abstract [en]

Healing of injured cancellous bone is characterized by a transient stage of rapid bone formation throughout the traumatized bone volume, often followed by similarly rapid resorption. This is different from the slower diaphyseal healing via an external callus. We, therefore, hypothesized that antiresorptive treatment might have an earlier positive effect in cancellous bone healing than in diaphyseal fractures. One hundred and twenty-three male C57bl6 mice received either an internally stabilized diaphyseal osteotomy of the femur or a screw inserted into the tibial metaphysis. The mice were randomized to daily alendronate injections (200 μg/kg/day), or control injections, and killed for mechanical testing after 14, 21, or 28 days. The hypothesis was tested by a three-way Anova (time, site, and drug). The ultimate force was increased by bisphosphonate treatment in both models. There was a significant interaction between time, site, and drug (p < 0.001) so that the full positive effect of alendronate was evident in the metaphysis at 14 days, but first after 28 days in the diaphysis. While the early effect in the metaphysis might be translated into earlier healing, the late effect in the diaphysis was due to delayed remodeling of the callus, which might have less clinical importance. © 2016 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res

Place, publisher, year, edition, pages
John Wiley & Sons, 2017
Keywords
fracture, bisphosphonate, metaphysis, cancellous bone, trabecular bone, alendronate
National Category
Clinical Medicine Orthopaedics Nursing
Identifiers
urn:nbn:se:liu:diva-130921 (URN)10.1002/jor.23316 (DOI)000399728400008 ()27233101 (PubMedID)
Funder
Swedish Research CouncilLinköpings universitetÖstergötland County CouncilEU, FP7, Seventh Framework Programme
Note

Funding agencies: Swedish Research Council [VR 02031-47-5]; Linkoping University; Ostergotland County Council; European Communitys Seventh Framework Programme [FP7/2007-2013]

Available from: 2016-08-31 Created: 2016-08-31 Last updated: 2018-05-03Bibliographically approved
Amirhosseini, M., Andersson, G., Aspenberg, P. & Fahlgren, A. (2017). Mechanical instability and titanium particles induce similar transcriptomic changes in a rat model for periprosthetic osteolysis and aseptic loosening. Bone Reports, 7, 17-25
Open this publication in new window or tab >>Mechanical instability and titanium particles induce similar transcriptomic changes in a rat model for periprosthetic osteolysis and aseptic loosening
2017 (English)In: Bone Reports, ISSN 2352-1872, Vol. 7, p. 17-25Article in journal (Refereed) Published
Abstract [en]

Wear debris particles released from prosthetic bearing surfaces and mechanical instability of implants are two main causes of periprosthetic osteolysis. While particle-induced loosening has been studied extensively, mechanisms through which mechanical factors lead to implant loosening have been less investigated. This study compares the transcriptional profiles associated with osteolysis in a rat model for aseptic loosening, induced by either mechanical instability or titanium particles. Rats were exposed to mechanical instability or titanium particles. After 15 min, 3, 48 or 120 h from start of the stimulation, gene expression changes in periprosthetic bone tissue was determined by microarray analysis. Microarray data were analyzed by PANTHER Gene List Analysis tool and Ingenuity Pathway Analysis (IPA). Both types of osteolytic stimulation led to gene regulation in comparison to unstimulated controls after 3, 48 or 120 h. However, when mechanical instability was compared to titanium particles, no gene showed a statistically significant difference (fold change = ± 1.5 and adjusted p-value = 0.05) at any time point. There was a remarkable similarity in numbers and functional classification of regulated genes. Pathway analysis showed several inflammatory pathways activated by both stimuli, including Acute Phase Response signaling, IL-6 signaling and Oncostatin M signaling. Quantitative PCR confirmed the changes in expression of key genes involved in osteolysis observed by global transcriptomics. Inflammatory mediators including interleukin (IL)-6, IL-1ß, chemokine (C-C motif) ligand (CCL)2, prostaglandin-endoperoxide synthase (Ptgs)2 and leukemia inhibitory factor (LIF) showed strong upregulation, as assessed by both microarray and qPCR. By investigating genome-wide expression changes we show that, despite the different nature of mechanical implant instability and titanium particles, osteolysis seems to be induced through similar biological and signaling pathways in this rat model for aseptic loosening. Pathways associated to the innate inflammatory response appear to be a major driver for osteolysis. Our findings implicate early restriction of inflammation to be critical to prevent or mitigate osteolysis and aseptic loosening of orthopedic implants.

Place, publisher, year, edition, pages
Elsevier, 2017
Keywords
Aseptic loosening; Implant; Instability; Microarray; Wear debris
National Category
Cell and Molecular Biology Orthopaedics
Identifiers
urn:nbn:se:liu:diva-146297 (URN)10.1016/j.bonr.2017.07.003 (DOI)28795083 (PubMedID)
Available from: 2018-04-07 Created: 2018-04-07 Last updated: 2019-03-08
Aspenberg, P. (2017). Placeboeffekten är övervärderad: »Återgång till medelvärdet« kan förklara förbättring efter skenbehandling – men misstolkas ofta. Läkartidningen, 114
Open this publication in new window or tab >>Placeboeffekten är övervärderad: »Återgång till medelvärdet« kan förklara förbättring efter skenbehandling – men misstolkas ofta
2017 (Swedish)In: Läkartidningen, ISSN 0023-7205, E-ISSN 1652-7518, Vol. 114Article in journal, Editorial material (Refereed) Published
Place, publisher, year, edition, pages
Stockholm, Sweden: Läkartidningen Förlag AB, 2017
National Category
Other Clinical Medicine
Identifiers
urn:nbn:se:liu:diva-146362 (URN)29292961 (PubMedID)
Available from: 2018-04-07 Created: 2018-04-07 Last updated: 2018-05-05Bibliographically approved
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