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Svensson RB, Slane LC, Magnusson SP, Bogaerts S. Ultrasound-based speckle-tracking in tendons: a critical analysis for the technician and the clinician. J Appl Physiol (1985) 2020; 130:445-456. [PMID: 33332991 DOI: 10.1152/japplphysiol.00654.2020] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Ultrasound has risen to the forefront as one of the primary tools in tendon research, with benefits including its relatively low cost, ease of use, and high safety. Moreover, it has been shown that cine ultrasound can be used to evaluate tendon deformation by tracking the motion of anatomical landmarks during physical movement. Estimates from landmark tracking, however, are typically limited to global tissue properties, such that clinically relevant regional nonuniformities may be missed. Fortunately, advancements in ultrasound scanning have led to the development of speckle-tracking algorithms, which enable the noninvasive measurement of in vivo local deformation patterns. Despite the successes in other fields, the adaptation of speckle-tracking to tendon research has presented some unique challenges as a result of tissue anisotropy and microstructural changes under load. With no generally accepted standards for its use, current methodological approaches vary substantially between studies and research groups. Therefore, the goal of this paper is to provide a summative review of the technical complexities and variations of speckle-tracking approaches being used and the impact these decisions may have on measured results and their interpretation. Variations in these approaches currently being used with relevant technical aspects are discussed first (for the technician), followed by a discussion of the more clinical considerations (for the clinician). Finally, a summary table of common challenges encountered when implementing speckle-tracking is provided, with suggested recommendations for minimizing the impact of such potential sources of error.
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Affiliation(s)
- Rene B Svensson
- Institute of Sports Medicine Copenhagen, Department of Orthopaedic Surgery M, Bispebjerg Hospital, Copenhagen, Denmark.,Center for Healthy Aging, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Laura C Slane
- Department of Mechanical Engineering, University of Rochester, Rochester, New York
| | - S Peter Magnusson
- Institute of Sports Medicine Copenhagen, Department of Orthopaedic Surgery M, Bispebjerg Hospital, Copenhagen, Denmark.,Center for Healthy Aging, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark.,Department of Physical and Occupational Therapy, Bispebjerg Hospital, Copenhagen, Denmark
| | - Stijn Bogaerts
- Research Unit on Locomotor and Neurological Disorders, Department of Development and Regeneration, KU Leuven, Leuven, Belgium.,Department of Physical and Rehabilitation Medicine, University Hospitals Leuven, Leuven, Belgium
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Peacock C, Lee E, Beral T, Cisek R, Tokarz D, Kreplak L. Buckling and Torsional Instabilities of a Nanoscale Biological Rope Bound to an Elastic Substrate. ACS NANO 2020; 14:12877-12884. [PMID: 32966048 DOI: 10.1021/acsnano.0c03695] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Rope-like structures are ubiquitous in Nature. They are supermolecular assemblies of macromolecules responsible for the structural and mechanical integrity of plant and animal tissues. Collagen fibrils with diameters between 50 and 500 nm and their helical supermolecular structure are good examples of such nanoscale biological ropes. Like man-made laid ropes, fibrils are typically loaded in tension, and due to their large aspect ratio, they are, in principle, prone to buckling and torsional instabilities. One way to study buckling of a rigid rod is to attach it to a stretched elastic substrate that is then returned to its original length. In the case of single collagen fibrils, the observed behavior depends on the degree of hydration. By going from buckling in ambient conditions to immersed in a buffer, fibrils go from the well-known sine wave response to a localized behavior reminiscent of the bird-caging of laid ropes. In addition, in ambient conditions, the sine wave response coexists with the formation of loops along the length of the fibrils, as observed for the torsional instability of a twisted filament when tension is decreased. This work provides direct evidence that single collagen fibrils are highly susceptible to axial compression because of their helical supermolecular structure. As a result, mammals that use collagen fibrils as their main load-bearing element in many tissues have evolved mitigating strategies that protect single fibrils from axial compression damage.
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Affiliation(s)
- Chris Peacock
- Department of Physics and Atmospheric Science, Dalhousie University, Halifax, NS B3H 4J5, Canada
| | - Eva Lee
- Department of Physics and Atmospheric Science, Dalhousie University, Halifax, NS B3H 4J5, Canada
| | - Theo Beral
- Department of Physics and Atmospheric Science, Dalhousie University, Halifax, NS B3H 4J5, Canada
| | - Richard Cisek
- Department of Chemistry, Saint Mary's University, Halifax, NS B3H 3C3, Canada
| | - Danielle Tokarz
- Department of Chemistry, Saint Mary's University, Halifax, NS B3H 3C3, Canada
| | - Laurent Kreplak
- Department of Physics and Atmospheric Science, Dalhousie University, Halifax, NS B3H 4J5, Canada
- School of Biomedical Engineering, Dalhousie University, Halifax, NS B3H 4R2, Canada
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Techniques for In Vivo Measurement of Ligament and Tendon Strain: A Review. Ann Biomed Eng 2020; 49:7-28. [PMID: 33025317 PMCID: PMC7773624 DOI: 10.1007/s10439-020-02635-5] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2020] [Accepted: 09/22/2020] [Indexed: 12/13/2022]
Abstract
The critical clinical and scientific insights achieved through knowledge of in vivo musculoskeletal soft tissue strains has motivated the development of relevant measurement techniques. This review provides a comprehensive summary of the key findings, limitations, and clinical impacts of these techniques to quantify musculoskeletal soft tissue strains during dynamic movements. Current technologies generally leverage three techniques to quantify in vivo strain patterns, including implantable strain sensors, virtual fibre elongation, and ultrasound. (1) Implantable strain sensors enable direct measurements of tissue strains with high accuracy and minimal artefact, but are highly invasive and current designs are not clinically viable. (2) The virtual fibre elongation method tracks the relative displacement of tissue attachments to measure strains in both deep and superficial tissues. However, the associated imaging techniques often require exposure to radiation, limit the activities that can be performed, and only quantify bone-to-bone tissue strains. (3) Ultrasound methods enable safe and non-invasive imaging of soft tissue deformation. However, ultrasound can only image superficial tissues, and measurements are confounded by out-of-plane tissue motion. Finally, all in vivo strain measurement methods are limited in their ability to establish the slack length of musculoskeletal soft tissue structures. Despite the many challenges and limitations of these measurement techniques, knowledge of in vivo soft tissue strain has led to improved clinical treatments for many musculoskeletal pathologies including anterior cruciate ligament reconstruction, Achilles tendon repair, and total knee replacement. This review provides a comprehensive understanding of these measurement techniques and identifies the key features of in vivo strain measurement that can facilitate innovative personalized sports medicine treatment.
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Slane LC, Dandois F, Bogaerts S, Scheys L, Vandenneucker H. Patellar tendon buckling in post-operative total knee arthroplasty patients is more prominent than in healthy controls. Med Eng Phys 2019; 69:28-32. [PMID: 31221515 DOI: 10.1016/j.medengphy.2019.06.005] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2018] [Revised: 03/30/2019] [Accepted: 06/07/2019] [Indexed: 10/26/2022]
Abstract
Recent evidence suggests the patellar tendon undergoes buckling during normal knee flexion, which likely contributes to the functioning of the extensor mechanism. Thus, evaluating buckling in patients following total knee arthroplasty (TKA), where extensor mechanism dysfunction remains a common complication, may be relevant. The study goals were to identify whether post-TKA patients exhibit differences in patellar tendon buckling from healthy, similarly-aged adults and whether such buckling correlates with knee and patellar tendon health. Patellar tendon buckling was assessed during passive knee flexion using ultrasound in post-TKA patients (n = 20; 12M, 68 ± 8 years) and compared with previously reported data from healthy adults (n = 12; 12M; 70 ± 8 years). Patients exhibited significantly larger (p < 0.01) buckling magnitude and angles than healthy adults, and reduced distal buckling was linked with better Knee Society Scores (p = 0.04, R2 = 0.24). The greater patellar tendon buckling observed in post-TKA patients could arise due to factors related to the surgery itself (e.g. infrapatellar fat pad resection) or it may be that post-TKA patients had greater patellar tendon buckling before their procedure. Alterations in patellar tendon buckling may predispose individuals to post-surgical complications including instability, anterior knee pain, and extensor mechanism dysfunction, with further work necessary to elucidate potential links.
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Affiliation(s)
- Laura Chernak Slane
- KU Leuven, Institute for Orthopaedic Research and Training, UZ Pellenberg, Weligerveld 1/Blok 1, Pellenberg, Leuven 3212, Belgium.
| | - Félix Dandois
- KU Leuven, Institute for Orthopaedic Research and Training, UZ Pellenberg, Weligerveld 1/Blok 1, Pellenberg, Leuven 3212, Belgium
| | - Stijn Bogaerts
- KU Leuven, Institute for Orthopaedic Research and Training, UZ Pellenberg, Weligerveld 1/Blok 1, Pellenberg, Leuven 3212, Belgium; University Hospitals Leuven, Campus Pellenberg, Pellenberg, Belgium
| | - Lennart Scheys
- KU Leuven, Institute for Orthopaedic Research and Training, UZ Pellenberg, Weligerveld 1/Blok 1, Pellenberg, Leuven 3212, Belgium; University Hospitals Leuven, Campus Pellenberg, Pellenberg, Belgium
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Abstract
This review, the first in a series of minireviews on the passive mechanical properties of skeletal muscles, seeks to summarize what is known about the muscle deformations that allow relaxed muscles to lengthen and shorten. Most obviously, when a muscle lengthens, muscle fascicles elongate, but this is not the only mechanism by which muscles change their length. In pennate muscles, elongation of muscle fascicles is accompanied by changes in pennation and changes in fascicle curvature, both of which may contribute to changes in muscle length. The contributions of these mechanisms to change in muscle length are usually small under passive conditions. In very pennate muscles with long aponeuroses, fascicle shear could contribute substantially to changes in muscle length. Tendons experience moderate axial strains even under passive loads, and, because tendons are often much longer than muscle fibers, even moderate tendon strains may contribute substantially to changes in muscle length. Data obtained with new imaging techniques suggest that muscle fascicle and aponeurosis strains are highly nonuniform, but this is yet to be confirmed. The development, validation, and interpretation of continuum muscle models informed by rigorous measurements of muscle architecture and material properties should provide further insights into the mechanisms that allow relaxed muscles to lengthen and shorten.
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Affiliation(s)
- R. D. Herbert
- Neuroscience Research Australia (NeuRA), Sydney, Australia
- University of New South Wales, Sydney, Australia
| | - B. Bolsterlee
- Neuroscience Research Australia (NeuRA), Sydney, Australia
- University of New South Wales, Sydney, Australia
| | - S. C. Gandevia
- Neuroscience Research Australia (NeuRA), Sydney, Australia
- University of New South Wales, Sydney, Australia
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Slane LC, Dandois F, Bogaerts S, Vandenneucker H, Scheys L. Non-uniformity in the healthy patellar tendon is greater in males and similar in different age groups. J Biomech 2018; 80:16-22. [PMID: 30224164 DOI: 10.1016/j.jbiomech.2018.08.021] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2018] [Revised: 07/20/2018] [Accepted: 08/11/2018] [Indexed: 12/12/2022]
Abstract
There is increasing evidence that tendons are heterogeneous and take advantage of structural mechanisms to enhance performance and reduce injury. Fascicle-sliding, for example, is used by energy-storing tendons to enable them to undergo large extensions while protecting the fascicles from damage. Reductions in fascicle-sliding capacity may thus predispose certain populations to tendinopathy. Evidence from the Achilles tendon of significant superficial-to-deep non-uniformity that is reduced with age supports this theory. Similar patellar tendon non-uniformity has been observed, but the effects of age and sex have yet to be assessed. Healthy adults (n = 50, 25M/25F) from a broad range of ages (23-80) were recruited and non-uniformity was quantified using ultrasound speckle-tracking during passive knee extension. Significant superficial-to-deep non-uniformity and proximal/distal variations were observed. No effect of age was found, but males exhibited significantly greater non-uniformity than females (p < 0.05). The results contrast with previous findings in the Achilles tendon; in this study, tendons and tendon regions at high risk for tendinopathy (i.e. males and proximal regions, respectively) exhibited greater non-uniformity, whereas high-risk Achilles tendons (i.e. older adults) previously showed reduced non-uniformity. This suggests that non-uniformity may be dominated by factors other than fascicle-sliding. Anatomically, the varied proximal attachment of the patellar tendon may influence non-uniformity, with quadriceps passive resistance limiting superficial tendon movement, thus linking flexibility, non-uniformity and injury risk. This study also provides evidence of a differential effect of aging on the patellar tendon compared with evidence from prior studies on other tendons necessitating further study to elucidate links between non-uniformity and injury.
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Affiliation(s)
- Laura Chernak Slane
- KU Leuven, Institute for Orthopaedic Research and Training, Leuven, Belgium.
| | - Félix Dandois
- KU Leuven, Institute for Orthopaedic Research and Training, Leuven, Belgium
| | - Stijn Bogaerts
- KU Leuven, Department of Development and Regeneration, Leuven, Belgium; University Hospitals Leuven, Campus Pellenberg, Pellenberg, Belgium
| | - Hilde Vandenneucker
- KU Leuven, Institute for Orthopaedic Research and Training, Leuven, Belgium; University Hospitals Leuven, Campus Pellenberg, Pellenberg, Belgium
| | - Lennart Scheys
- KU Leuven, Institute for Orthopaedic Research and Training, Leuven, Belgium; University Hospitals Leuven, Campus Pellenberg, Pellenberg, Belgium
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Slane LC, Dandois F, Bogaerts S, Vandenneucker H, Scheys L. Patellar tendon buckling is altered with age. Med Eng Phys 2018; 59:15-20. [PMID: 30061067 DOI: 10.1016/j.medengphy.2018.04.024] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2018] [Revised: 03/22/2018] [Accepted: 04/30/2018] [Indexed: 10/28/2022]
Abstract
Recent evidence has revealed that the patellar tendon exhibits buckling during passive knee extension, wherein the tendon folds back onto itself. The clinical relevance of such buckling is unclear, but it has been suggested that it serves to protect the patellar tendon from rupture when subjected to a sudden extreme contraction. Although prior evidence suggests buckling occurs universally, it is poorly understood, and may be influenced by age and sex. Healthy adults (n = 41, aged 21-80 years) were recruited to assess age- and sex-based differences in patellar tendon buckling during passive knee extension. 93% of subjects exhibited buckling in extension, with buckling more prominent in the distal tendon. No age- or sex-based differences in buckling magnitude were observed, but a significant age-based difference in buckling angle was found, with the tendon unbuckling later in flexion in younger adults compared with middle-aged (p = 0.025) and older (p = 0.014) adults. Intrinsic factors were also linked with buckling; for example, smaller maximum knee extension (i.e. less flexibility) correlated with smaller buckling magnitude (p = 0.037, R2 = 0.116), suggesting a link between patellar tendon buckling and joint-level mechanics. These results suggest that buckling is an inherent component of normal knee function that older adults may be failing to take advantage of, predisposing them to injury. Further study will be critical to elucidate the clinical implications of patellar tendon buckling.
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Affiliation(s)
- Laura Chernak Slane
- Institute for Orthopaedic Research and Training (IORT), KU Leuven, UZ Pellenberg, Weligerveld 1/Blok 1, Pellenberg, 3212 Leuven, Belgium.
| | - Félix Dandois
- Institute for Orthopaedic Research and Training (IORT), KU Leuven, UZ Pellenberg, Weligerveld 1/Blok 1, Pellenberg, 3212 Leuven, Belgium
| | - Stijn Bogaerts
- Institute for Orthopaedic Research and Training (IORT), KU Leuven, UZ Pellenberg, Weligerveld 1/Blok 1, Pellenberg, 3212 Leuven, Belgium; University Hospitals Leuven, Campus Pellenberg, Pellenberg, Belgium
| | - Hilde Vandenneucker
- Institute for Orthopaedic Research and Training (IORT), KU Leuven, UZ Pellenberg, Weligerveld 1/Blok 1, Pellenberg, 3212 Leuven, Belgium; University Hospitals Leuven, Campus Pellenberg, Pellenberg, Belgium
| | - Lennart Scheys
- Institute for Orthopaedic Research and Training (IORT), KU Leuven, UZ Pellenberg, Weligerveld 1/Blok 1, Pellenberg, 3212 Leuven, Belgium; University Hospitals Leuven, Campus Pellenberg, Pellenberg, Belgium
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Gijsbertse K, Sprengers A, Naghibi Beidokhti H, Nillesen M, de Korte C, Verdonschot N. Strain imaging of the lateral collateral ligament using high frequency and conventional ultrasound imaging: An ex-vivo comparison. J Biomech 2018; 73:233-237. [PMID: 29628130 PMCID: PMC5947823 DOI: 10.1016/j.jbiomech.2018.03.035] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2017] [Revised: 03/16/2018] [Accepted: 03/21/2018] [Indexed: 12/16/2022]
Abstract
Recent first attempts of in situ ultrasound strain imaging in collateral ligaments encountered a number of challenges and illustrated a clear need for additional studies and more thorough validation of the available strain imaging methods. Therefore, in this study we experimentally validated ultrasound strain measurements of ex vivo human lateral collateral ligaments in an axial loading condition. Moreover, the use of high frequency ultrasound (>20 MHz) for strain measurement was explored and its performance compared to conventional ultrasound. The ligaments were stretched up to 5% strain and ultrasound measurements were compared to surface strain measurements from optical digital image correlation (DIC) techniques. The results show good correlations between ultrasound based and DIC based strain measures with R2 values of 0.71 and 0.93 for high frequency and conventional ultrasound, subsequently. The performance of conventional ultrasound was significantly higher compared to high frequency ultrasound strain imaging, as the high frequency based method seemed more prone to errors. This study demonstrates that ultrasound strain imaging is feasible in ex vivo lateral collateral ligaments, which are relatively small structures. Additional studies should be designed for a more informed assessment of optimal in vivo strain measurements in collateral knee ligaments.
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Affiliation(s)
- Kaj Gijsbertse
- Orthopaedic Research Laboratory, Department of Orthopedics, Radboud University Medical Center, Nijmegen, The Netherlands.
| | - André Sprengers
- Orthopaedic Research Laboratory, Department of Orthopedics, Radboud University Medical Center, Nijmegen, The Netherlands; Laboratory of Biomechanical Engineering, University of Twente, Enschede, The Netherlands
| | - Hamid Naghibi Beidokhti
- Orthopaedic Research Laboratory, Department of Orthopedics, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Maartje Nillesen
- Medical Ultrasound Imaging Center (MUSIC), Department of Radiology and Nuclear Medicine, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Chris de Korte
- Medical Ultrasound Imaging Center (MUSIC), Department of Radiology and Nuclear Medicine, Radboud University Medical Center, Nijmegen, The Netherlands; Physics of Fluids Group, MESA+ Institute for Nanotechnology, and MIRA Institute for Biomedical Technology and Technical Medicine, University of Twente, Enschede, The Netherlands
| | - Nico Verdonschot
- Orthopaedic Research Laboratory, Department of Orthopedics, Radboud University Medical Center, Nijmegen, The Netherlands; Laboratory of Biomechanical Engineering, University of Twente, Enschede, The Netherlands
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Slane LC, Bogaerts S, Thelen DG, Scheys L. Nonuniform Deformation of the Patellar Tendon During Passive Knee Flexion. J Appl Biomech 2018; 34:14-22. [PMID: 28787221 DOI: 10.1123/jab.2017-0067] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
The purpose of this study was to evaluate localized patterns of patellar tendon deformation during passive knee flexion. Ultrasound radiofrequency data were collected from the patellar tendons of 20 healthy young adults during knee flexion over a range of motion of 50°-90° of flexion. A speckle tracking approach was used to compute proximal and distal tendon displacements and elongations. Nonuniform tissue displacements were visible in the proximal tendon (P < .001), with the deep tendon undergoing more distal displacement than the superficial tendon. In the distal tendon, more uniform tendon motion was observed. Spatial variations in percent elongation were also observed, but these varied along the length of the tendon (P < .002), with the proximal tendon remaining fairly isometric while the distal tendon underwent slight elongation. These results suggest that even during passive flexion the tendon undergoes complex patterns of deformation. Proximal tendon nonuniformity may arise from its complex anatomy where the deep tendon inserts onto the patella and the superficial tendon extends to the quadriceps tendon. Such heterogeneity is not captured in whole tendon average assessments, emphasizing the relevance of considering localized tendon mechanics, which may be key to understanding tendon behavior and precursors to injury and disease.
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Hösl M, Böhm H, Seltmann M, Dussa CU, Döderlein L. Relationship between radiographic patella-alta pathology and walking dysfunction in children with bilateral spastic Cerebral Palsy. Gait Posture 2018; 60:28-34. [PMID: 29149666 DOI: 10.1016/j.gaitpost.2017.11.006] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/18/2016] [Revised: 11/02/2017] [Accepted: 11/09/2017] [Indexed: 02/02/2023]
Abstract
BACKGROUND Patella-alta is very common in patients with Cerebral Palsy (CP). While several diagnostic x-ray indices have been developed for patella-alta in general, the specific relationship with walking dysfunction in CP is only partly understood. METHODS 33 participants with bilateral spastic CP between 4 and 20 years (GMFCS I-II without previous surgery) that underwent 3D gait analysis as well as a radiographic exam within 0.8 (SD 1.2) months were retrospectively included. The Caton-Deschamps, the Insall-Salvati and the Koshino-Index, as well as the moment-arms of the quadriceps, the pattelar-tendon length and patellar tilt angle were analyzed from x-rays. During gait, tempo-spatial parameters, the knee flexion kinematics, the knee moments and the moment impulse were calculated and correlated to x-ray parameters. RESULTS Smaller quadriceps moment-arms were related to slower walking speed (r=0.48, P=0.005) and less knee extension during stance (r=0.68 P<0.001). Smaller quadriceps moment arms and longer patellar-tendons were also significantly related to a larger knee flexion moment impulse in the second half of the stance phase (r=-0.36, P=0.045 and r=0.39, P=0.028) and hence to more abnormal knee loads. Yet, none of the traditional indices was related to any parameter of gait. INTERPRETATION Traditional radiographic indices for patella-alta possess little to no informative value for walking dysfunction in individuals with CP suspected to have knee pathology. Smaller moment-arms are a key feature of patellofemoral pathology in CP reducing the knee extensor mechanism, an aspect which is not sufficiently picked up by traditional indices.
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Affiliation(s)
- Matthias Hösl
- Schön Klinik Bad Aibling, Hospital for Neurology and Neurological Rehabilitation, Kolbermoorer Str. 72, 83043, Bad Aibling, Germany.
| | - Harald Böhm
- Orthopaedic Hospital for Children, Behandlungszentrum Aschau GmbH, Bernauer Str. 18, 83229, Aschau im Chiemgau, Germany
| | - Michaela Seltmann
- Department of Sport and Health Sciences, Technische Universität München, Uptown München-Campus D, Georg-Brauchle-Ring 60/62, 80992, München, Germany; Schön Klinik München Harlaching, Harlachinger Straße 51, 81547, München, Germany
| | - Chakravarthy Ugandhar Dussa
- Orthopaedic Hospital for Children, Behandlungszentrum Aschau GmbH, Bernauer Str. 18, 83229, Aschau im Chiemgau, Germany
| | - Leonhard Döderlein
- Orthopaedic Hospital for Children, Behandlungszentrum Aschau GmbH, Bernauer Str. 18, 83229, Aschau im Chiemgau, Germany
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