Per Kjaer

Per Kjaer
University of Southern Denmark | SDU · Institute of Sports Science and Clinical Biomechanics

PT, MSc, PhD

About

108
Publications
32,401
Reads
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3,737
Citations
Introduction
Per Kjaer is currently professor of musculoskeletal research with a focus on back and neck pain. The position is a joint venture between University of Southern Denmark (SDU) and University College Lillebaelt (UCL). Per Kjaer is heavily engaged in the GLA:D Back project and its implementation. Further to this, he is driving the research aspects of the new MRI Center at UCL and planning a new approach to the management of people with longlasting back pain seen in municipality rehabilitation centres. He is also the leader of the longitudinal cohort study 'Backs on Funen' in which he has organised data collection on more than 850 participants regularly since 2000. Per Kjaer has led several groups generating guidelines for evidence-based physiotherapy for people with back pain.
Additional affiliations
February 2009 - present
University of Southern Denmark
Position
  • Professor (Associate)
Description
  • Risk factors for low back pain, Translational research
February 2009 - July 2016
University of Southern Denmark
Position
  • Professor (Associate)
August 1998 - February 2009
Hospital of Lillebaelt
Position
  • Clinician, PhD-Student, researcher
Description
  • I worked as a clinician at the Spine Centre when it was established in Ringe. Later I did my PhD work in the Spine Centre and worked there as a researcher after that.

Publications

Publications (108)
Article
Full-text available
Associations between multifidus muscle morphology and degenerative pathologies have been implied in patients with non-specific low back pain, but it is unknown how these are influenced by pathology severity, number, or distribution. MRI measures of pure multifidus muscle cross-sectional area (CSA) were acquired from 522 patients presenting with low...
Preprint
Full-text available
Background: Systematic reviews and studies exploring associations between morphologic change of paraspinal muscles and low back pain or related outcomes such as disability, radiculopathy, and physical workload, have reported conflicting results. This study explores the associations between lumbar multifidus muscle quality and clinical outcomes rela...
Article
Full-text available
We investigated the longitudinal associations between physical activity (PA), lumbar multifidus morphology, and impactful low back pain (LBP) in young people. Nine-year-old children were recruited from 25 primary schools and followed up at age 13, 16, and 21 years. We measured PA with accelerometers at age 9, 13, and 16; quantified patterns of lumb...
Preprint
Full-text available
Background: There is ongoing interest in assessing the lumbar multifidus muscles to determine their role in patients with non-specific low back pain. While associations between lumbar-related pain, altered multifidus morphology, and/or degenerative pathologies have been implied, it is unknown how these associations may be influenced by the severity...
Article
Full-text available
Importance: Lower back pain (LBP) is a prevalent and challenging condition in primary care. The effectiveness of an individually tailored self-management support tool delivered via a smartphone app has not been rigorously tested. Objective: To investigate the effectiveness of selfBACK, an evidence-based, individually tailored self-management sup...
Article
Background and objective: Motor performance during childhood and adolescence is recognized as a relevant determinant of present and future health, but its effects on back pain (BP) remain unclear. In this systematic review, we aimed to identify the association between motor performance and BP in children and adolescents. Databases and data treatm...
Article
Objectives To explore the magnetic resonance imaging (MRI) feedback report as a health care encounter for generating shared diagnostic meaning. Methods An exploratory, qualitative case study was conducted using video observation of the MRI report of findings, individual face-to-face and telephonic interviews. Results From fourteen distinct encoun...
Article
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Background A paradigm shift away from clinician-led management of people with chronic disorders to people playing a key role in their own care has been advocated. At the same time, good health is recognised as the ability to adapt to changing life circumstances and to self-manage. Under this paradigm, successful management of persistent back pain i...
Article
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PurposeStudies using magnetic resonance imaging to assess lumbar multifidus cross-sectional area frequently utilize T1 or T2-weighted sequences, but seldom provide the rationale for their sequence choice. However, technical considerations between their acquisition protocols could impact on the ability to assess lumbar multifidus anatomy or its fat/...
Preprint
Full-text available
BACKGROUND International guidelines consistently endorse promotion of self-management for people with low back pain (LBP), however, implementation of these guidelines remains a challenge. Digital health interventions, such as those that can be provided by smartphone apps, have been proposed as a promising mode to support self-management in people w...
Article
Background: International guidelines consistently endorse the promotion of self-management for people with low back pain (LBP); however, implementation of these guidelines remains a challenge. Digital health interventions, such as those that can be provided by smartphone apps, have been proposed as a promising mode of supporting self-management in...
Article
Full-text available
Background Shoulder pain is common, with a lifetime prevalence of up to 67%. Evidence is conflicting in relation to imaging findings and pain in the shoulder. Sonoelastography can be used to estimate tissue stiffness and may be a clinically relevant technique for diagnosing and monitoring tendon healing. Purpose To evaluate changes in supraspinatu...
Article
Full-text available
Background The relationship between motor performance and back pain in children and adolescents remains unclear. This article describes the protocol for a systematic review to summarize the knowledge about the association between motor performance, such as agility, flexibility, balance, strength, muscle endurance, and cardiorespiratory fitness, and...
Article
Full-text available
Background: Lumbar disc degeneration seen on magnetic resonance imaging (MRI) is defined as loss of signal intensity and/or disc height, alone or in combination with other MRI findings. The MRI findings and thresholds used to define disc degeneration vary in the literature, and their associations with low back pain (LBP) remain uncertain. Objecti...
Article
Background: Effective, inexpensive, and low-risk interventions are needed for patients with nonspecific persistent low back pain (NS-PLBP) who are unresponsive to primary care interventions. Cognitive functional therapy (CFT) is a multidimensional behavioral self-management approach that has demonstrated promising results in primary care and has n...
Article
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Background We aimed to explore the discriminative validity of ultrasound strain elastography (SEL) between patients with painful supraspinatus tendinopathy and healthy control shoulders, as well as the associations between SEL and magnetic resonance imaging (MRI), conventional ultrasound (tendon thickness), and the Disabilities of the Arm, Shoulder...
Article
Full-text available
Objective To determine the inter-examiner reproducibility for judging the presence, number and location of leg-pain referring myofascial trigger points, and their prevalence in patients with low back pain with and without concomitant leg pain referral. Design An inter-examiner reproducibility study. Setting An outpatient public Hospital Spine Cen...
Preprint
Background: Studies using magnetic resonance imaging to assess lumbar multifidus cross-sectional area frequently utilize T1 or T2-weighted sequences, but seldom provide the rationale for their sequence choice. However, technical considerations between their acquisition protocols could impact on the ability to assess lumbar multifidus anatomy or its...
Article
Full-text available
Background Previous studies of patients with neck pain have reported a high variability in prevalence of MRI findings of disc degeneration, disc herniation etc. This is most likely due to small and heterogenous study populations. Reasons for only including small study samples could be the high cost and time-consuming procedures of having radiologis...
Article
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Background Taking the natural course of recurrent and fluctuating low back pain (LBP) seen in longitudinal studies of adults into consideration, the aetiology and development of LBP in children and adolescents also needs to be reflected in a long-term course. Therefore, a systematic critical literature review was undertaken to assess the natural co...
Article
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Background: Neck pain is a major public health problem. Our objective was to describe differences in measures of movement and posture between people with and without neck pain. Methods: PubMed and Embase were searched before 15 February 2019 for studies comparing people with neck pain with controls using electronic measurements of neck movement...
Preprint
BACKGROUND Low back pain (LBP) is prevalent across all social classes, in all age groups and across industrialised as well as developing countries. From a global perspective LBP is considered the leading cause of disability and it negatively impacts everyday life and wellbeing. Self-management is a recommended first-line treatment and mobile applic...
Article
Background: Low back pain (LBP) is prevalent across all social classes, in all age groups, and across industrialized and developing countries. From a global perspective, LBP is considered the leading cause of disability and negatively impacts everyday life and well-being. Self-management is a recommended first-line treatment, and mobile apps are a...
Article
Full-text available
Background Clinical guidelines for management of low back pain (LBP) are not routinely implemented in practice, and guidelines rarely offer tools for implementation. Therefore, we developed GLA:D® Back, a standardised intervention of patient education and supervised exercises. This pilot study tested the feasibility of implementing GLA:D Back in cl...
Article
Full-text available
Objectives The reliability of ultrasonic strain elastography (SEL) used to detect abnormalities in the supraspinatus tendon is unclear. Thus, the aim of this study was to investigate the reliability of SEL in the supraspinatus tendon. Design An intra-rater and inter-rater reliability study. Setting A single-centre study conducted at the Universit...
Article
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Background Reassuring patient education and exercise therapy are widely recommended interventions for back pain in clinical guidelines. However, many patients are offered non-guideline endorsed options, and strategies for effective implementation of guideline-based care have not yet been developed. This protocol outlines the evaluation of a strateg...
Article
Full-text available
Background Clinical guidelines recommend that people with back pain be given information and education about their back pain, advice to remain active and at work, and exercises to improve mobility and physical activity. Guidelines, however, rarely describe how this is best delivered. The aim of this paper is to present the development, theories, an...
Article
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Background Individual study results have demonstrated unclear relationships between neurocompressive disorders and paraspinal muscle morphology. This systematic review aimed to synthesize current evidence regarding the relationship lumbar neurocompressive disorders may have with lumbar paraspinal muscle morphology. Methods Searches were conducted...
Article
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Background Previous systematic reviews have reported positive associations between Modic changes (MCs) and low back pain (LBP), but due to their narrow scope and new primary studies, there is a need for a comprehensive systematic review. Our objectives were to investigate if MCs are associated with non-specific LBP and/or activity limitation and if...
Data
Data extraction and risk of bias assessment. (XLSX)
Data
Protocol registered at PROSPERO. (PDF)
Data
Articles excluded in full text assessment. (DOCX)
Article
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Background Research into the clinical importance of spinal MRI findings in patients with low back pain (LBP) has primarily focused on single imaging findings, such as Modic changes or disc degeneration, and found only weak associations with the presence of pain. However, numerous MRI findings almost always co-exist in the lumbar spine and are often...
Article
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Purpose: To summarise recommendations about 20 non-surgical interventions for recent onset (<12 weeks) non-specific low back pain (LBP) and lumbar radiculopathy (LR) based on two guidelines from the Danish Health Authority. Methods: Two multidisciplinary working groups formulated recommendations based on the GRADE approach. Results: Sixteen re...
Article
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Purpose: To summarise recommendations about 21 selected non-surgical interventions for recent onset (<12 weeks) non-specific neck pain (NP) and cervical radiculopathy (CR) based on two guidelines from the Danish Health Authority. Methods: Two multidisciplinary working groups formulated recommendations based on the GRADE approach. Results: Twel...
Article
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Background Low back pain (LBP) is a common cause of disability and is ranked as the most burdensome health condition globally. Self-management, including components on increased knowledge, monitoring of symptoms, and physical activity, are consistently recommended in clinical guidelines as cost-effective strategies for LBP management and there is i...
Article
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Background Wireless, wearable, inertial motion sensor technology introduces new possibilities for monitoring spinal motion and pain in people during their daily activities of work, rest and play. There are many types of these wireless devices currently available but the precision in measurement and the magnitude of measurement error from such devic...
Article
Background: The impact of physical therapy on the outcomes of patients with acute low back pain (LBP) stratified by the STart Back Screening Tool (SBST) is unclear. Objective: The purpose of this study was to compare the outcomes of patients with acute LBP who were stratified as medium or high risk. Design: This was a secondary analysis of a r...
Article
Study design: A cross-sectional and longitudinal analysis using 2 different data sets OBJECTIVE.: To investigate if the number of different MRI findings present is more strongly associated with low back pain (LBP) than single MRI findings. Summary of background data: Most previous studies have investigated the associations between single MRI fin...
Article
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Background Few longitudinal studies have described the variation in LBP and its impact over time at an individual level. The aims of this study were to: 1) determine the prevalence of LBP in three surveys over a 9-year period in the Danish general population, using five different definitions of LBP, 2) study their individual long-term courses, and...
Article
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Purposes We used two different methods to classify low back pain (LBP) in the general population (1) to assess the overlapping of individuals within the different subgroups in those two classifications, (2) to explore if the associations between LBP and some selected bio-psychosocial factors are similar, regardless which of the two classifications...
Article
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Background: Magnetic resonance imaging (MRI) is used to identify spinal pathoanatomy in people with persistent low back pain. However, the clinical relevance of spinal degenerative MRI findings remains uncertain. Although multiple MRI findings are almost always present at the same time, research into the association with clinical outcomes (such as...
Article
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Background A lumbar disc herniation (LDH) is a localised displacement of disc material, which may initiate changes in the disc and adjacent structures such as the nerve root and the spinal canal. Knowledge about how morphological changes in the disc relate to changes in other spinal structures might give the clinician a better understanding of the...
Article
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Explore the relationships between preoperative findings and clinical outcome following lumbar disc surgery, and investigate the prognostic value of physical examination findings after accounting for information acquired from the clinical history. We recruited 55 adult patients scheduled for first time, single-level lumbar discectomy. Participants u...