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Pineda Guzman RA, Naughton N, Majumdar S, Damon B, Kersh ME. Assessment of Mechanically Induced Changes in Helical Fiber Microstructure Using Diffusion Tensor Imaging. Ann Biomed Eng 2024; 52:832-844. [PMID: 38151645 DOI: 10.1007/s10439-023-03420-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2023] [Accepted: 12/04/2023] [Indexed: 12/29/2023]
Abstract
Noninvasive methods to detect microstructural changes in collagen-based fibrous tissues are necessary to differentiate healthy from damaged tissues in vivo but are sparse. Diffusion Tensor Imaging (DTI) is a noninvasive imaging technique used to quantitatively infer tissue microstructure with previous work primarily focused in neuroimaging applications. Yet, it is still unclear how DTI metrics relate to fiber microstructure and function in musculoskeletal tissues such as ligament and tendon, in part because of the high heterogeneity inherent to such tissues. To address this limitation, we assessed the ability of DTI to detect microstructural changes caused by mechanical loading in tissue-mimicking helical fiber constructs of known structure. Using high-resolution optical and micro-computed tomography imaging, we found that static and fatigue loading resulted in decreased sample diameter and a re-alignment of the macro-scale fiber twist angle similar with the direction of loading. However, DTI and micro-computed tomography measurements suggest microstructural differences in the effect of static versus fatigue loading that were not apparent at the bulk level. Specifically, static load resulted in an increase in diffusion anisotropy and a decrease in radial diffusivity suggesting radially uniform fiber compaction. In contrast, fatigue loads resulted in increased diffusivity in all directions and a change in the alignment of the principal diffusion direction away from the constructs' main axis suggesting fiber compaction and microstructural disruptions in fiber architecture. These results provide quantitative evidence of the ability of DTI to detect mechanically induced changes in tissue microstructure that are not apparent at the bulk level, thus confirming its potential as a noninvasive measure of microstructure in helically architected collagen-based tissues, such as ligaments and tendons.
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Affiliation(s)
| | - Noel Naughton
- Beckman Institute for Advanced Science & Technology, University of Illinois Urbana-Champaign, Urbana, IL, USA
| | - Shreyan Majumdar
- Beckman Institute for Advanced Science & Technology, University of Illinois Urbana-Champaign, Urbana, IL, USA
| | - Bruce Damon
- Beckman Institute for Advanced Science & Technology, University of Illinois Urbana-Champaign, Urbana, IL, USA
- Carle Clinical Imaging Research Program, Stephens Family Clinical Research Institute, Carle Health, Urbana, IL, USA
- Department of Bioengineering, University of Illinois Urbana-Champaign, Urbana, IL, USA
- Department of Biomedical Engineering, Vanderbilt University, Nashville, TN, USA
- Vanderbilt University Institute of Imaging Science, Vanderbilt University Medical Center, Nashville, TN, USA
- Department of Radiology and Radiological Science, Vanderbilt University, Nashville, TN, USA
- Carle Illinois College of Medicine, University of Illinois Urbana-Champaign, Urbana, IL, USA
| | - Mariana E Kersh
- Department of Mechanical Science & Engineering, University of Illinois Urbana-Champaign, Urbana, IL, USA.
- Beckman Institute for Advanced Science & Technology, University of Illinois Urbana-Champaign, Urbana, IL, USA.
- Carle Illinois College of Medicine, University of Illinois Urbana-Champaign, Urbana, IL, USA.
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2
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Chen W, Zhou Q, Tang J. Material Properties of Fiber Bundles of the Superficial Medial Collateral Ligament of the Knee Joint. J Biomech Eng 2024; 146:031003. [PMID: 38217110 DOI: 10.1115/1.4064476] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2023] [Accepted: 12/27/2023] [Indexed: 01/15/2024]
Abstract
The superficial medial collateral ligament (sMCL) of the human knee joint has functionally separate anterior and posterior fiber bundles. The two bundles are alternatively loaded as the knee flexion angle changes during walking. To date, the two bundles are usually not distinguished in knee ligament simulations because there has been little information about their material properties. In this study, we conducted quasi-static tensile tests on the sMCL of matured porcine stifle joints and obtained the material properties of the anterior bundle (AB), posterior bundle (PB), and whole ligament (WL). AB and PB have similar failure stress but different threshold strain, modulus, and failure strain. As a result, we recommend assigning different material properties (i.e., modulus and failure strain) to the two fiber bundles to realize biofidelic ligament responses in human body models. However, it is often inconvenient to perform tensile tests on AB and PB. Hence, we proposed a microstructural model-based approach to predict the material properties of AB and PB from the test results of WL. Such obtained modulus values of AB and PB had an error of 2% and 0.3%, respectively, compared with those measured from the tests. This approach can reduce the experimental cost for acquiring the needed mechanical property data for simulations.
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Affiliation(s)
- Wentao Chen
- State Key Laboratory of Automotive Safety and Energy, School of Vehicle and Mobility, Tsinghua University, Beijing 100084, China
| | - Qing Zhou
- State Key Laboratory of Automotive Safety and Energy, School of Vehicle and Mobility, Tsinghua University, Beijing 100084, China
| | - Jisi Tang
- State Key Laboratory of Automotive Safety and Energy, School of Vehicle and Mobility, Tsinghua University, Beijing 100084, China
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3
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Iannucci LE, Riak MB, Meitz E, Bersi MR, Gruev V, Lake SP. Effect of matrix properties on transmission and reflectance mode division-of-focal-plane Stokes polarimetry. JOURNAL OF BIOMEDICAL OPTICS 2023; 28:102902. [PMID: 37441242 PMCID: PMC10334992 DOI: 10.1117/1.jbo.28.10.102902] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/05/2023] [Revised: 05/18/2023] [Accepted: 05/23/2023] [Indexed: 07/15/2023]
Abstract
Significance Division-of-focal-plane Stokes polarimetry is emerging as a powerful tool for the microstructural characterization of soft tissues. How individual extracellular matrix (ECM) properties influence polarimetric signals in reflectance or transmission modes of quantitative polarized light imaging (QPLI) is not well understood. Aim We aimed to investigate how ECM properties affect outcomes obtained from division-of-focal-plane polarimetric imaging in reflectance or transmission modes. Approach Tunable collagen gel phantoms were used to modulate ECM properties of anisotropy, collagen density, crosslinking, and absorber density; the effects of degree of linear polarization (DoLP) and angle of polarization (AoP) on polarimetry outcomes were assessed. A model biological tissue (i.e., bovine tendon) was similarly imaged and evaluated using both reflectance and transmission modes. Results Reflectance QPLI resulted in decreased DoLP compared with transmission mode. A 90 deg shift in AoP was observed between modes but yielded similar spatial patterns. Collagen density had the largest effect on outcomes besides anisotropy in both imaging modes. Conclusions Both imaging modes were sufficiently sensitive to detect structural anisotropy differences in gels of varying fiber alignment. Conclusions drawn from phantom experiments should carry over when interpreting data from more complex tissues and can help provide context for interpretation of other Stokes polarimetry data.
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Affiliation(s)
- Leanne E. Iannucci
- Washington University in St. Louis, McKelvey School of Engineering, Department of Biomedical Engineering, St. Louis, Missouri, United States
| | - Matthew B. Riak
- Washington University in St. Louis, McKelvey School of Engineering, Department of Mechanical Engineering and Materials Science, St. Louis, Missouri, United States
| | - Ethan Meitz
- Washington University in St. Louis, McKelvey School of Engineering, Department of Mechanical Engineering and Materials Science, St. Louis, Missouri, United States
| | - Matthew R. Bersi
- Washington University in St. Louis, McKelvey School of Engineering, Department of Mechanical Engineering and Materials Science, St. Louis, Missouri, United States
| | - Viktor Gruev
- University of Illinois Urbana-Champaign, Department of Electrical and Computer Engineering, Champaign, Illinois, United States
| | - Spencer P. Lake
- Washington University in St. Louis, McKelvey School of Engineering, Department of Biomedical Engineering, St. Louis, Missouri, United States
- Washington University in St. Louis, McKelvey School of Engineering, Department of Mechanical Engineering and Materials Science, St. Louis, Missouri, United States
- Washington University in St. Louis, School of Medicine, Department of Orthopaedic Surgery, St. Louis, Missouri, United States
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4
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Beaulieu ML, Ashton-Miller JA, Wojtys EM. Loading mechanisms of the anterior cruciate ligament. Sports Biomech 2023; 22:1-29. [PMID: 33957846 PMCID: PMC9097243 DOI: 10.1080/14763141.2021.1916578] [Citation(s) in RCA: 19] [Impact Index Per Article: 19.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/31/2020] [Accepted: 04/08/2021] [Indexed: 01/26/2023]
Abstract
This review identifies the three-dimensional knee loads that have the highest risk of injuring the anterior cruciate ligament (ACL) in the athlete. It is the combination of the muscular resistance to a large knee flexion moment, an external reaction force generating knee compression, an internal tibial torque, and a knee abduction moment during a single-leg athletic manoeuvre such as landing from a jump, abruptly changing direction, or rapidly decelerating that results in the greatest ACL loads. While there is consensus that an anterior tibial shear force is the primary ACL loading mechanism, controversy exists regarding the secondary order of importance of transverse-plane and frontal-plane loading in ACL injury scenarios. Large knee compression forces combined with a posteriorly and inferiorly sloped tibial plateau, especially the lateral plateau-an important ACL injury risk factor-causes anterior tibial translation and internal tibial rotation, which increases ACL loading. Furthermore, while the ACL can fail under a single supramaximal loading cycle, recent evidence shows that it can also fail following repeated submaximal loading cycles due to microdamage accumulating in the ligament with each cycle. This challenges the existing dogma that non-contact ACL injuries are predominantly due to a single manoeuvre that catastrophically overloads the ACL.
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Affiliation(s)
- Mélanie L. Beaulieu
- Department of Orthopaedic Surgery, University of Michigan, Ann Arbor, MI, USA
| | - James A. Ashton-Miller
- Department of Mechanical Engineering, University of Michigan, Ann Arbor, MI, USA
- Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI, USA
| | - Edward M. Wojtys
- Department of Orthopaedic Surgery, University of Michigan, Ann Arbor, MI, USA
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5
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Wu X, Pankow M, Onuma T, Huang HYS, Peters K. Comparison of High-Speed Polarization Imaging Methods for Biological Tissues. SENSORS (BASEL, SWITZERLAND) 2022; 22:8000. [PMID: 36298350 PMCID: PMC9607302 DOI: 10.3390/s22208000] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/08/2022] [Revised: 10/03/2022] [Accepted: 10/18/2022] [Indexed: 06/16/2023]
Abstract
We applied a polarization filter array and high-speed camera to the imaging of biological tissues during large, dynamic deformations at 7000 frames per second. The results are compared to previous measurements of similar specimens using a rotating polarizer imaging system. The polarization filter eliminates motion blur and temporal bias from the reconstructed collagen fiber alignment angle and retardation images. The polarization imaging configuration dose pose additional challenges due to the need for calibration of the polarization filter array for a given sample in the same lighting conditions as during the measurement.
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Affiliation(s)
- Xianyu Wu
- Department of Mechanical and Aerospace Engineering, North Carolina State University, Raleigh, NC 27695, USA
- School of Mechanical Engineering and Automation, Fuzhou University, 2 Xueyuan Rd., Fuzhou 350116, China
| | - Mark Pankow
- Department of Mechanical and Aerospace Engineering, North Carolina State University, Raleigh, NC 27695, USA
| | - Taka Onuma
- Photron Limited, Kanda Jinbo-Cho 1-105, Chiyoda-Ku, Tokyo 101-0051, Japan
| | - Hsiao-Ying Shadow Huang
- Department of Mechanical and Aerospace Engineering, North Carolina State University, Raleigh, NC 27695, USA
| | - Kara Peters
- Department of Mechanical and Aerospace Engineering, North Carolina State University, Raleigh, NC 27695, USA
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Chang PS, Solon LF, Lake SP, Castile RM, Hill JR, Brophy RH. Mechanical and Microstructural Properties of Meniscus Roots Vary by Location. Am J Sports Med 2022; 50:2733-2739. [PMID: 35862621 DOI: 10.1177/03635465221106746] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
BACKGROUND Despite the growing awareness of the clinical significance of meniscus root tears, there are relatively limited biomechanical and microstructural data available on native meniscus roots that could improve our understanding of why they are injured and how to best treat them. PURPOSE/HYPOTHESIS The purpose of the study was to measure the material and microstructural properties of meniscus roots using mechanical testing and quantitative polarized light imaging. The hypothesis was that these properties vary by location (medial vs lateral, anterior vs posterior) and by specific root (anteromedial vs anterolateral, posteromedial vs posterolateral). STUDY DESIGN Descriptive laboratory study. METHODS Anterior and posterior meniscus roots of the medial and lateral meniscus were isolated from 22 cadavers (10 female, 12 male; mean ± SD age, 47.1 ± 5.1 years) and loaded in uniaxial tension. Quantitative polarized light imaging was used to measure collagen fiber organization and realignment under load. Samples were subjected to preconditioning, stress-relaxation, and a ramp to failure. Time-dependent relaxation behavior was quantified. Modulus values were computed in the toe and linear regions of the stress-strain curves. The degree of linear polarization (DoLP) and angle of polarization-measures of the strength and direction of collagen alignment, respectively-were calculated during the stress-relaxation test and at specific strain values throughout the ramp to failure (zero, transition, and linear strain). RESULTS Anterior roots had larger moduli than posterior roots in the toe (P = .007) and linear (P < .0001) regions and larger average DoLP values at all points of the ramp to failure (zero, P = .016; transition, P = .004; linear, P = .002). Posterior roots had larger values across all regions in terms of standard deviation angle of polarization (P < .001). Lateral roots had greater modulus values versus medial roots in the toe (P = .027) and linear (P = .014) regions. Across all strain points, posterolateral roots had smaller mean DoLP values than posteromedial roots. CONCLUSION Posterior meniscus roots have smaller modulus values and more disorganized collagen alignment at all strain levels when compared with anterior roots. Posterolateral roots have lower strength of collagen alignment versus posteromedial roots. CLINICAL RELEVANCE These data findings may explain at least in part the relative paucity of anterior meniscus root tears and the predominance of traumatic posterolateral roots tears as compared with degenerative posteromedial root tears.
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Affiliation(s)
- Peter S Chang
- Department of Orthopedic Surgery, Washington University School of Medicine in St. Louis, St Louis, Missouri, USA
| | - Lorenzo F Solon
- Department of Mechanical Engineering, and Material Science, Washington University in St. Louis, St Louis, Missouri, USA
| | - Spencer P Lake
- Department of Mechanical Engineering, and Material Science, Washington University in St. Louis, St Louis, Missouri, USA
| | - Ryan M Castile
- Department of Mechanical Engineering, and Material Science, Washington University in St. Louis, St Louis, Missouri, USA
| | - J Ryan Hill
- Department of Orthopedic Surgery, Washington University School of Medicine in St. Louis, St Louis, Missouri, USA
| | - Robert H Brophy
- Department of Orthopedic Surgery, Washington University School of Medicine in St. Louis, St Louis, Missouri, USA
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7
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Solon LF, Castile RM, Smith MV, Lake SP. Mechanical properties and microstructural organization of common ulnar collateral ligament grafts: Palmaris longus and gracilis tendons. J Orthop Res 2022; 40:1865-1871. [PMID: 34786748 DOI: 10.1002/jor.25209] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/29/2021] [Revised: 10/25/2021] [Accepted: 10/30/2021] [Indexed: 02/04/2023]
Abstract
Ulnar collateral ligament (UCL) injuries are becoming increasingly common. The palmaris longus (PL) and gracilis (GR) tendons are the most common grafts used in UCL reconstructions. While clinical studies have demonstrated relatively similar outcomes for either graft, there is little quantitative data describing these grafts from a material perspective, specifically the mechanical and microstructural properties of these tissues and how they respond under dynamic loading. The purpose of this descriptive laboratory study was to quantify and compare the mechanical and microstructural properties of PL and GR tendons. A total of 13 PL and 11 GR cadaveric human tendons were obtained. Each specimen was divided into three subregions and subjected to preconditioning, ramp-and-hold stress-relaxation and ramp-to-failure testing. Mechanical parameters were computed for each sample, and a polarized light imaging technique was used to simultaneously evaluate dynamic microstructural properties during testing. The PL had larger toe- and linear-region modulus values than the GR. Within the GR, the distal subregion had stronger collagen alignment than the proximal subregion at the zero, transition and linear portions of the stress-strain curve. The PL and GR, have similar mechanical properties and similar microstructural alignment under load. The PL graft has similar properties throughout its length whereas the GR properties exhibited slight differences in strength of alignment along its length. The PL and GR exhibit larger moduli values and more strongly/uniformly aligned collagenous microstructure when qualitatively compared to data previously published on the native UCL.
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Affiliation(s)
- Lorenzo F Solon
- Department of Biology, Washington University in St. Louis, St. Louis, Missouri, USA
| | - Ryan M Castile
- Department of Mechanical Engineering and Materials Science, Washington University in St. Louis, St. Louis, Missouri, USA
| | - Matthew V Smith
- Department of Orthopaedic Surgery, Washington University in St. Louis, St. Louis, Missouri, USA
| | - Spencer P Lake
- Department of Mechanical Engineering and Materials Science, Washington University in St. Louis, St. Louis, Missouri, USA.,Department of Orthopaedic Surgery, Washington University in St. Louis, St. Louis, Missouri, USA
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8
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Castile RM, Cannon PC, Smith MV, Brophy RH, Lake SP. Donor age and sex have limited effects on the mechanical and microstructural properties of human connective tissues. J Orthop Res 2022; 40:1844-1852. [PMID: 34676910 DOI: 10.1002/jor.25200] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/29/2021] [Revised: 09/15/2021] [Accepted: 10/18/2021] [Indexed: 02/04/2023]
Abstract
Connective tissues, such as tendons, ligaments, and capsules, play a large role in locomotion and joint stability and are often subjected to traumatic injuries and degeneration. The purpose of this study was to evaluate if the mechanical and microstructural properties of connective tissues correlate with the age and sex of the human donor. Dissected samples were prepared for mechanical testing, consisting of 10 cycles of preconditioning, a stress-relaxation ramp and hold, and a quasi-static ramp to failure. During the testing protocol, the microstructural organization of tissues was analyzed using quantitative polarized light imaging. A linear mixed model was used to assess whether tissue type, donor age, or donor sex were significantly associated with mechanical and microstructural tissue properties. Tissue type had a significant effect on all parameters, while donor age and sex did not. Groupings by tissue type (i.e., tendon vs. ligament vs. capsule) were evident for microstructural data, with tendons having a tighter grouping and ligaments having a larger spread of values. The interaction of tissue type and age yielded a significant effect for linear modulus only (p = 0.007), with the palmaris tendon appearing to have the largest contribution to this effect. There were no significant interaction effects between sex and tissue type or donor age. Donor age appears to affect linear modulus in some, but not all, tissue types. Otherwise, age and sex do not have significant effects on the mechanical and microstructural properties of the range of connective tissues that were analyzed in this study.
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Affiliation(s)
- Ryan M Castile
- Department of Mechanical Engineering & Materials Science, Washington University in St. Louis, St. Louis, Missouri, USA
| | - Paul C Cannon
- Statistics and Data Science, Bringham Young University - Idaho, Rexburg, Idaho, USA
| | - Matthew V Smith
- Department of Orthopaedic Surgery, Washington University in St. Louis, St. Louis, Missouri, USA
| | - Robert H Brophy
- Department of Orthopaedic Surgery, Washington University in St. Louis, St. Louis, Missouri, USA
| | - Spencer P Lake
- Department of Mechanical Engineering & Materials Science, Washington University in St. Louis, St. Louis, Missouri, USA.,Department of Orthopaedic Surgery, Washington University in St. Louis, St. Louis, Missouri, USA
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Badawy CR, Jan K, Beck EC, Fleet N, Taylor J, Ford K, Waterman BR. Contemporary Principles for Postoperative Rehabilitation and Return to Sport for Athletes Undergoing Anterior Cruciate Ligament Reconstruction. Arthrosc Sports Med Rehabil 2022; 4:e103-e113. [PMID: 35141542 PMCID: PMC8811493 DOI: 10.1016/j.asmr.2021.11.002] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2021] [Accepted: 11/09/2021] [Indexed: 12/16/2022] Open
Abstract
Despite advancements in our understanding of anterior cruciate ligament (ACL) injury prevention and nonsurgical management, ACL reconstruction continues to occur at an alarming rate. Among athletic patients, individuals participating in basketball, soccer, and football have the highest incidence of ACL injury, often requiring surgical intervention. To ensure the optimal treatment strategy for return to sport and prevention of secondary graft re-tear, it is important to tailor to the specific demands of the injured athlete and apply evidence-based best practices and rehabilitation principles. The purpose of this review is to provide readers with a brief background regarding ACL injuries, a focused review of clinical outcome studies after ACL reconstruction, and an updated framework with expert-guided recommendations for postoperative rehabilitation and return to sporting activity. Currently, there is no gold standard for rehabilitation after ACL reconstruction, highlighting the need for robust studies evaluating the best modalities for athlete rehabilitation, as well as determining the efficacy of new tools for improving therapy including blood flow restriction therapy and neuromuscular electrical stimulation. Based on clinical experience, a renewed focus on objective, criteria-based milestones may maximize the ability of return to preinjury levels of athletic function.
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Affiliation(s)
- Charles R Badawy
- Department of Orthopedic Surgery, Wake Forest Baptist Health, Winston-Salem, North Carolina, U.S.A
| | - Kyleen Jan
- University of Illinois College of Medicine, Chicago, Illinois, U.S.A
| | - Edward C Beck
- Department of Orthopedic Surgery, Wake Forest Baptist Health, Winston-Salem, North Carolina, U.S.A
| | - Niles Fleet
- Department of Athletics, Wake Forest University, Winston-Salem, North Carolina, U.S.A
| | - Jeffrey Taylor
- Department of Physical Therapy, High Point University, High Point, North Carolina, U.S.A
| | - Kevin Ford
- Department of Physical Therapy, High Point University, High Point, North Carolina, U.S.A
| | - Brian R Waterman
- Department of Orthopedic Surgery, Wake Forest Baptist Health, Winston-Salem, North Carolina, U.S.A
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Kiapour AM, Flannery SW, Murray MM, Miller PE, Fleming BC, Sant N, Portilla G, Sanborn R, Freiberger C, Henderson R, Barnett S, Ecklund K, Yen YM, Kramer DE, Micheli LJ, Fleming BC. Regional Differences in Anterior Cruciate Ligament Signal Intensity After Surgical Treatment. Am J Sports Med 2021; 49:3833-3841. [PMID: 34668789 PMCID: PMC8829819 DOI: 10.1177/03635465211047554] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
BACKGROUND Magnetic resonance-based measurements of signal intensity have been used to track healing of surgically treated anterior cruciate ligaments (ACLs). However, it is unknown how the signal intensity values in different regions of the ligament or graft change during healing. HYPOTHESES (1) Normalized signal intensity of the healing graft or repaired ACL is heterogeneous; (2) temporal changes in normalized signal intensity values differ among the tibial, middle, and femoral regions; and (3) there are no differences in regional normalized signal intensity values 2 years postoperatively among grafts, repaired ACLs, and contralateral native ACLs. STUDY DESIGN Cohort study; Level of evidence, 2. METHODS Magnetic resonance imaging scans were analyzed from patients in a trial comparing ACL reconstruction (n = 35) with bridge-enhanced ACL repair (n = 65). The ACLs were segmented from images acquired at 6, 12, and 24 months postoperatively and were partitioned into 3 sections along the longitudinal axis (femoral, middle, and tibial). Linear mixed modeling was used to compare location-specific differences in normalized ligament signal intensity among time points (6, 12, and 24 months) and groups (ACL reconstruction, repair, and contralateral native ACL). RESULTS For grafts, the middle region had a higher mean normalized signal intensity when compared with the femoral region at all time points (P < .01) but compared with the tibial region only at 6 months (P < .01). For repaired ACLs, the middle region had a higher mean normalized signal intensity versus the femoral region at all time points (P < .01) but versus the tibial region only at 6 and 12 months (P < .04). From 6 to 24 months, the grafts showed the greatest reduction in normalized signal intensity in the femoral and middle regions (vs tibial regions; P < .01), while there were no regional differences in repaired ACLs. At 2 years after surgery, repaired ACLs had a lower normalized signal intensity in the tibial region as compared with reconstructed grafts and contralateral native ACLs (P < .01). CONCLUSION The results suggest that graft remodeling is location specific. Repaired ACLs were more homogeneous, with lower or comparable normalized signal intensity values at 2 years as compared with the contralateral native ACL and reconstructed grafts.
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Affiliation(s)
- Ata M. Kiapour
- Department of Orthopaedic Surgery and Sports Medicine, Boston Children’s Hospital, Harvard Medical School, Boston, MA 02115
| | - Sean W. Flannery
- Department of Orthopaedics, Warren Alpert Medical School of Brown University, Rhode Island Hospital, Providence RI 02818
| | - Martha M. Murray
- Department of Orthopaedic Surgery and Sports Medicine, Boston Children’s Hospital, Harvard Medical School, Boston, MA 02115
| | - Patricia E. Miller
- Department of Orthopaedic Surgery and Sports Medicine, Boston Children’s Hospital, Harvard Medical School, Boston, MA 02115
| | | | - Braden C. Fleming
- Department of Orthopaedics, Warren Alpert Medical School of Brown University, Rhode Island Hospital, Providence RI 02818
| | - Nicholas Sant
- Investigation performed at Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts, USA
| | - Gabriela Portilla
- Investigation performed at Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts, USA
| | - Ryan Sanborn
- Investigation performed at Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts, USA
| | - Christina Freiberger
- Investigation performed at Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts, USA
| | - Rachael Henderson
- Investigation performed at Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts, USA
| | - Samuel Barnett
- Investigation performed at Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts, USA
| | - Kirsten Ecklund
- Investigation performed at Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts, USA
| | - Yi-Meng Yen
- Investigation performed at Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts, USA
| | - Dennis E Kramer
- Investigation performed at Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts, USA
| | - Lyle J Micheli
- Boston Children's Hospital Boston, Massachusetts, USA.,Investigation performed at Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts, USA
| | - Braden C Fleming
- Department of Orthopaedics, Warren Alpert Medical School of Brown University, Rhode Island Hospital, Providence, Rhode Island, USA.,Investigation performed at Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts, USA
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11
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Ranmuthu CDS, MacKay JW, Crowe VA, Kaggie JD, Kessler DA, McDonnell SM. Quantitative analysis of the ACL and PCL using T1rho and T2 relaxation time mapping: an exploratory, cross-sectional comparison between OA and healthy control knees. BMC Musculoskelet Disord 2021; 22:916. [PMID: 34717593 PMCID: PMC8556921 DOI: 10.1186/s12891-021-04755-y] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/16/2021] [Accepted: 09/28/2021] [Indexed: 12/18/2022] Open
Abstract
Background Quantitative magnetic resonance imaging (MRI) methods such as T1rho and T2 mapping are sensitive to changes in tissue composition, however their use in cruciate ligament assessment has been limited to studies of asymptomatic populations or patients with posterior cruciate ligament tears only. The aim of this preliminary study was to compare T1rho and T2 relaxation times of the anterior cruciate ligament (ACL) and posterior cruciate ligament (PCL) between subjects with mild-to-moderate knee osteoarthritis (OA) and healthy controls. Methods A single knee of 15 patients with mild-to-moderate knee OA (Kellgren-Lawrence grades 2–3) and of 6 age-matched controls was imaged using a 3.0 T MRI. Three-dimensional (3D) fat-saturated spoiled gradient recalled-echo images were acquired for morphological assessment and T1ρ- and T2-prepared pseudo-steady-state 3D fast spin echo images for compositional assessment of the cruciate ligaments. Manual segmentation of whole ACL and PCL, as well as proximal / middle / distal thirds of both ligaments was carried out by two readers using ITK-SNAP and mean relaxation times were recorded. Variation between thirds of the ligament were assessed using repeated measures ANOVAs and differences in these variations between groups using a Kruskal-Wallis test. Inter- and intra-rater reliability were assessed using intraclass correlation coefficients (ICCs). Results In OA knees, both T1rho and T2 values were significantly higher in the distal ACL when compared to the rest of the ligament with the greatest differences in T1rho (e.g. distal mean = 54.5 ms, proximal = 47.0 ms, p < 0.001). The variation of T2 values within the PCL was lower in OA knees (OA: distal vs middle vs proximal mean = 28.5 ms vs 29.1 ms vs 28.7 ms, p = 0.748; Control: distal vs middle vs proximal mean = 26.4 ms vs 32.7 ms vs 33.3 ms, p = 0.009). ICCs were excellent for the majority of variables. Conclusion T1rho and T2 mapping of the cruciate ligaments is feasible and reliable. Changes within ligaments associated with OA may not be homogeneous. This study is an important step forward in developing a non-invasive, radiological biomarker to assess the ligaments in diseased human populations in-vivo. Supplementary Information The online version contains supplementary material available at 10.1186/s12891-021-04755-y.
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Affiliation(s)
- Chanuka D S Ranmuthu
- School of Clinical Medicine, Addenbrooke's Hospital, University of Cambridge, Cambridge, CB2 0SP, UK. .,, London, UK.
| | - James W MacKay
- Department of Radiology, Addenbrooke's Hospital, University of Cambridge, Cambridge, CB2 0QQ, UK.,Norwich Medical School, University of East Anglia, Norwich Research Park, Norwich, NR4 7UY, UK
| | - Victoria A Crowe
- Cambridge University Hospitals NHS Foundation Trust, Addenbrooke's Hospital, Cambridge, CB2 0QQ, UK
| | - Joshua D Kaggie
- Department of Radiology, Addenbrooke's Hospital, University of Cambridge, Cambridge, CB2 0QQ, UK
| | - Dimitri A Kessler
- Department of Radiology, Addenbrooke's Hospital, University of Cambridge, Cambridge, CB2 0QQ, UK
| | - Stephen M McDonnell
- Division of Trauma & Orthopaedic Surgery, Addenbrooke's Hospital, University of Cambridge, Cambridge, CB2 0QQ, UK
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Sikidar A, Marieswaran M, Kalyanasundaram D. Estimation of forces on anterior cruciate ligament in dynamic activities. Biomech Model Mechanobiol 2021; 20:1533-1546. [PMID: 33880694 DOI: 10.1007/s10237-021-01461-5] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2020] [Accepted: 04/10/2021] [Indexed: 01/13/2023]
Abstract
In this work, a nonlinear strain rate dependent plugin developed for the OpenSim® platform was used to estimate the instantaneous strain rate (ISR) and the forces on the ACL's anteromedial (aACL) and posterolateral (pACL) bundles during walking and sudden change of direction of running termed as 'plant-and-cut' (PC). The authors obtained the kinematics data for walking via optical motion capture. PC movements, along with running kinematics, were obtained from the literature. A nonlinear plugin developed for ligaments was interfaced with OpenSim® platform to simulate walking and PC motions with a flexed knee and an extended knee. PC phase is sandwiched between an approach phase and take-off phase and was studied at various event velocities (1.8, 3, and 4.2 m s-1), and angles of PC (23°, 34°, and 45°) as encountered in adult ball games. In both cases of PC-with-extended knee and PC-with-flexed-knee, the maximum forces on both the ACL bundles were observed after the take-off phase. A maximum force of ~ 35 N kg-1 of body weight (BW) was observed on aACL after the take-off phase for an event velocity of 4.2 m s-1. In the posterolateral bundle (pACL), the maximum forces (~ 40 N kg-1 of BW) were observed towards the end of the mid-swing phase (after the take-off phase) for the various combinations of the parameters studied. The forces observed in the simulation of PC-with-flexed-knee and PC-with-extended-knee has resulted in magnitude higher than sustainable by the adults. This study is novel in attempting to incorporate differing rates-of-strain that have been shown to alter soft tissue properties into the OpenSim® musculoskeletal model. The proposed model can be used by researchers to predict the forces during various kinematic activities for other soft tissues.
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Affiliation(s)
- Arnab Sikidar
- Centre for Biomedical Engineering, Indian Institute of Technology Delhi, New Delhi, 110016, India
| | - M Marieswaran
- Department of Sports Biomechanics, School of Sports Sciences, Central University of Rajasthan, Bandar Sindi, Ajmer, Rajasthan, 305817, India
| | - Dinesh Kalyanasundaram
- Centre for Biomedical Engineering, Indian Institute of Technology Delhi, New Delhi, 110016, India.
- Department of Biomedical Engineering, All India Institute of Medical Sciences, New Delhi, 110029, India.
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13
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Patel RM, Castile RM, Jenkins MJ, Lake SP, Brophy RH. Microstructural and Mechanical Properties of the Anterolateral Ligament of the Knee. Am J Sports Med 2021; 49:172-182. [PMID: 33381993 DOI: 10.1177/0363546520974381] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
BACKGROUND The variable anatomy and controversy of the anterolateral ligament (ALL) reflect the complex relationship among the anterolateral knee structures. PURPOSE/HYPOTHESIS The purpose was to quantify the microstructural and mechanical properties of the ALL as compared with the anterolateral capsule (ALC) and lateral collateral ligament (LCL). The primary hypotheses were that (1) there is no difference in these properties between the ALL and ALC and (2) the LCL has significantly different properties from the ALL and ALC. STUDY DESIGN Descriptive laboratory study. METHODS The LCL, ALL, and ALC were harvested from 25 cadaveric knees. Mechanical testing and microstructural analyses were performed using quantitative polarized light imaging. The average degree of linear polarization (AVG DoLP; mean strength of collagen alignment) and standard deviation of the angle of polarization (STD AoP; degree of variation in collagen angle orientation) were calculated. RESULTS Linear region moduli were not different between the ALC and ALL (3.75 vs 3.66 MPa, respectively; P > .99). AVG DoLP values were not different between the ALC and ALL in the linear region (0.10 vs 0.10; P > .99). Similarly, STD AoP values were not different between the ALC and ALL (24.2 vs 21.7; P > .99). The LCL had larger modulus, larger AVG DoLP, and smaller STD AoP values than the ALL and ALC. Of 25 knee specimens, 3 were observed to have a distinct ALL, which exhibited larger modulus, larger AVG DoLP, and smaller STD AoP values as compared with nondistinct ALL samples. CONCLUSION There were no differences in the mechanical and microstructural properties between the ALL and ALC. The ALC and ALL exhibited comparably weak and disperse collagen alignment. However, when a distinct ALL was present, the properties were suggestive of a ligamentous structure. CLINICAL RELEVANCE The properties of the ALL are similar to those of a ligament only when a distinct ALL is present, but otherwise, for the majority of specimens, ALL properties are closer to those of the capsule. Variability in the ligamentous structure of the ALL suggests that it may be more important in some patients than others and reconstruction may be considered in selective patients. Further study is needed to better understand its selective role and optimal indications for reconstruction.
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Affiliation(s)
- Ronak M Patel
- Washington University in St Louis, St Louis, Missouri, USA
| | - Ryan M Castile
- Washington University in St Louis, St Louis, Missouri, USA
| | | | - Spencer P Lake
- Washington University in St Louis, St Louis, Missouri, USA
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14
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Fiber splay precludes the direct identification of ligament material properties: Implications for ACL graft selection. J Biomech 2020; 113:110104. [PMID: 33161304 DOI: 10.1016/j.jbiomech.2020.110104] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2020] [Revised: 09/08/2020] [Accepted: 10/17/2020] [Indexed: 11/20/2022]
Abstract
Anterior cruciate ligament (ACL) injuries typically require surgical reconstruction to restore adequate knee stability. The middle third of an injured patient's patellar tendon (PT) is a commonly used graft for ACL reconstruction. However, many clinicians and researchers question whether it is the best option, as several studies have suggested that it is a stiffer material than the ACL. Still, there is little to no consensus on even the most basic material property of ligaments/tendons: the tangent modulus in the fiber direction, or slope of the linear portion of the uniaxial stress-strain curve. In this study, we investigate the effect of fiber splay (the tendency of collagen fibers to spread out near the enthesis) on the apparent tangent modulus. Using a simplified theoretical model, we establish a quantity we call the splay ratio, which describes the relationship between splay geometry and the apparent tangent modulus. We then more rigorously investigate the effect of the splay ratio on the apparent tangent modulus of the ovine PT and anteromedial and posterolateral regions of the ACL using experimental and computational methods. Both approaches confirmed that splay geometry significantly affects the apparent material behavior. Because true material properties are independent of geometry, we conclude that the macroscopic response of ligaments and tendons is not sufficient for the characterization of their material properties, but rather is reflective of both material and structural properties. We further conclude that the PT is probably not a stiffer material than ACL, but that the PT graft is likely a stiffer structure than either ACL region.
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15
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Castile RM, Jenkins MJ, Lake SP, Brophy RH. Microstructural and Mechanical Properties of Grafts Commonly Used for Cruciate Ligament Reconstruction. J Bone Joint Surg Am 2020; 102:1948-1955. [PMID: 32740264 DOI: 10.2106/jbjs.19.01395] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
BACKGROUND Injuries to the anterior cruciate ligament and posterior cruciate ligament are common, and often are treated with reconstruction. Limited quantitative data are available describing material properties of grafts used for reconstructions such as the bone-patellar tendon-bone (BPTB), hamstring tendon (HS), and quadriceps tendon (QT). The purpose of this study was to quantify and compare microstructural and mechanical properties of BPTB, HS, and QT grafts. METHODS Forty specimens (13 BPTB, 13 HS, and 14 QT grafts) from 24 donors were used. Specimens were subjected to preconditioning, stress relaxation, and ramp to failure. Mechanical parameters were calculated for each sample, and polarization imaging was used to evaluate the direction and strength of collagen fiber alignment during testing. RESULTS QT had the largest modulus values, and HS had the smallest. BPTB exhibited the least disperse collagen organization, while HS were the least strongly aligned. Microstructural properties showed more strongly aligned collagen with increasing load for all grafts. All tissues showed stress relaxation and subtle microstructural changes during the hold period. CONCLUSIONS The mechanical and microstructural properties differed significantly among BPTB, HS, and QT grafts. QT exhibited the largest moduli and greatest strength of collagen alignment, while HS had the smallest moduli and least strongly aligned collagen. CLINICAL RELEVANCE This study identified mechanical and microstructural differences among common grafts and between these grafts and the cruciate ligaments they replace. Further research is needed to properly interpret the clinical relevance of these differences.
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Affiliation(s)
- Ryan M Castile
- Departments of Mechanical Engineering & Materials Science (R.M.C., M.J.J., and S.P.L.) and Orthopaedic Surgery (S.P.L. and R.H.B.), Washington University in St. Louis, St. Louis, Missouri
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16
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Owen King N, Gruev V, Lake SP. Implementation of a logarithmic division-of-focal-plane polarimeter to quantify changes in collagen alignment at varying levels of illumination. APPLIED OPTICS 2020; 59:7813-7820. [PMID: 32976451 DOI: 10.1364/ao.398362] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/01/2020] [Accepted: 08/02/2020] [Indexed: 06/11/2023]
Abstract
We examine the impact of illumination, aperture, and sample thickness on two division-of-focal-plane (DoFP) polarimeters, one created using a standard 3 T pixel and the other with a forward-biased, logarithmic pixel. Across all measured metrics the logarithmic DoFP polarimeter was better able to track real-time changes in collagen alignment than the standard DoFP polarimeter.
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17
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Otani T, Kobayashi Y, Tanaka M. Computational study of kinematics of the anterior cruciate ligament double-bundle structure during passive knee flexion–extension. Med Eng Phys 2020; 83:56-63. [DOI: 10.1016/j.medengphy.2020.07.015] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2019] [Revised: 05/28/2020] [Accepted: 07/13/2020] [Indexed: 10/23/2022]
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18
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Robbins AB, Freed AD, Moreno MR. Characterizing the non-linear mechanical behavior of native and biomimetic engineered tissues in 1D with physically meaningful parameters. J Mech Behav Biomed Mater 2020; 102:103509. [DOI: 10.1016/j.jmbbm.2019.103509] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2019] [Revised: 10/16/2019] [Accepted: 10/23/2019] [Indexed: 01/06/2023]
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19
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Nagai K, Gale T, Chiba D, Su F, Fu FH, Anderst W. The Complex Relationship Between In Vivo ACL Elongation and Knee Kinematics During Walking and Running. J Orthop Res 2019; 37:1920-1928. [PMID: 31042309 PMCID: PMC6719793 DOI: 10.1002/jor.24330] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/21/2018] [Accepted: 04/23/2019] [Indexed: 02/04/2023]
Abstract
In vivo anterior cruciate ligament (ACL) bundle (anteromedial bundle [AMB] and posterolateral bundle [PLB]) relative elongation during walking and running remain unknown. In this study, we aimed to investigate in vivo ACL relative elongation over the full gait cycle during walking and running. Ten healthy volunteers walked and ran at a self-selected pace on an instrumented treadmill while biplane radiographs of the knee were acquired at 100 Hz (walking) and 150 Hz (running). Tibiofemoral kinematics were determined using a validated model-based tracking process. The boundaries of ACL insertions were identified using high-resolution magnetic resonance imaging (MRI). The AMB and PLB centroid-to-centroid distances were calculated from the tracked bone motions, and these bundle lengths were normalized to their respective lengths on MRI to calculate relative elongation. Maximum AMB relative elongation during running (6.7 ± 2.1%) was significantly greater than walking (5.0 ± 1.7%, p = 0.043), whereas the maximum PLB relative elongation during running (1.1 ± 2.1%) was significantly smaller than walking (3.4 ± 2.3%, p = 0.014). During running, the maximum AMB relative elongation was significantly greater than the maximum PLB relative elongation (p < 0.001). ACL relative elongations were correlated with tibiofemoral six degree-of-freedom kinematics. The AMB and PLB demonstrate similar elongation patterns but different amounts of relative elongation during walking and running. The complex relationship observed between ACL relative elongation and knee kinematics indicates that ACL relative elongation is impacted by tibiofemoral kinematic parameters in addition to flexion/extension. These findings suggest that ACL strain is region-specific during walking and running. © 2019 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 37:1920-1928, 2019.
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Affiliation(s)
- Kanto Nagai
- Department of Orthopaedic Surgery, University of Pittsburgh, Pittsburgh, Pennsylvania, USA.,Department of Orthopaedic Surgery, Kobe University Graduate School of Medicine, Kobe, Hyogo, Japan
| | - Tom Gale
- Department of Orthopaedic Surgery, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Daisuke Chiba
- Department of Orthopaedic Surgery, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Favian Su
- Department of Orthopaedic Surgery, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Freddie H. Fu
- Department of Orthopaedic Surgery, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - William Anderst
- Department of Orthopaedic Surgery, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
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20
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Tisherman R, Wilson K, Horvath A, Byrne K, De Groot J, Musahl V. Allograft for knee ligament surgery: an American perspective. Knee Surg Sports Traumatol Arthrosc 2019; 27:1882-1890. [PMID: 30888445 DOI: 10.1007/s00167-019-05425-2] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/13/2018] [Accepted: 02/15/2019] [Indexed: 11/25/2022]
Abstract
PURPOSE Allografts are frequently use for ligamentous reconstruction at the knee. In the United States, tissue donation and distribution are highly regulated processes with thorough oversight from private and government entities. Allograft is widely available in the United States and allograft procurement is a large industry with varying procurement, sterilization, processing, and distribution procedures. It is important to understand allograft regulation and processing which may affect graft mechanical properties and biological graft integration. METHODS English-language literature, United States government and regulatory agency statues pertaining to allograft procurement, distribution, and usage were reviewed and the findings summarized. RESULTS During the processing of allograft, multiple factors including sterilization procedures, irradiation, storage conditions, and graft type all affect the biomechanical properties of the allograft tissue. Biological incorporation and ligamentization of allograft does occur, but at a slower rate compared with autograft. For ligamentous reconstruction around the knee, allograft offers shorter operative time, no donor-site morbidity, but has shown an increased risk for graft failure compared to autograft. CONCLUSION This article reviews the regulations on graft tissue within the United States, factors affecting the biomechanics of allograft tissue, differences in allograft tissue choices, and the use of allograft for anterior cruciate ligament reconstruction and multiligamentous knee injury reconstruction. LEVEL OF EVIDENCE V.
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Affiliation(s)
- Robert Tisherman
- Department of Orthopaedic Surgery, University of Pittsburgh, 3471 Fifth Avenue Suite 1010, Pittsburgh, PA, 15213, USA.
| | - Kevin Wilson
- Department of Orthopaedic Surgery, University of Pittsburgh, 3471 Fifth Avenue Suite 1010, Pittsburgh, PA, 15213, USA
| | - Alexandra Horvath
- Department of Orthopaedics, Institute of Clinical Sciences, The Sahlgrenska Academy, University of Gothenburg, Göteborg, Sweden
| | - Kevin Byrne
- Department of Orthopaedic Surgery, University of Pittsburgh, 3471 Fifth Avenue Suite 1010, Pittsburgh, PA, 15213, USA
| | - Joseph De Groot
- Department of Orthopaedic Surgery, University of Pittsburgh, 3471 Fifth Avenue Suite 1010, Pittsburgh, PA, 15213, USA
| | - Volker Musahl
- Department of Orthopaedic Surgery, University of Pittsburgh, 3471 Fifth Avenue Suite 1010, Pittsburgh, PA, 15213, USA
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21
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Smith MV, Castile RM, Brophy RH, Dewan A, Bernholt D, Lake SP. Mechanical Properties and Microstructural Collagen Alignment of the Ulnar Collateral Ligament During Dynamic Loading. Am J Sports Med 2019; 47:151-157. [PMID: 30495972 DOI: 10.1177/0363546518812416] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
BACKGROUND The ulnar collateral ligament (UCL) microstructural organization and collagen fiber realignment in response to load are unknown. PURPOSE/HYPOTHESIS The purpose was to describe the real-time microstructural collagen changes in the anterior bundle (AB) and posterior bundle (PB) of the UCL with tensile load. It was hypothesized that the UCL AB is stronger and stiffer with more highly aligned collagen during loading when compared with the UCL PB. STUDY DESIGN Descriptive laboratory study. METHODS The AB and PB from 34 fresh cadaveric specimens were longitudinally sectioned to allow uniform light passage for quantitative polarized light imaging. Specimens were secured to a tensile test machine and underwent cyclic preconditioning, a ramp-and-hold stress-relaxation test, and a quasi-static ramp to failure. A division-of-focal-plane polarization camera captured real-time pixelwise microstructural data of each sample during stress-relaxation and at the zero, transition, and linear points of the stress-strain curve. The SD of the angle of polarization determined the deviation of the average direction of collagen fibers in the tissue, while the average degree of linear polarization evaluated the strength of collagen alignment in those directions. Since the data were nonnormally distributed, the median ± interquartile range are presented. RESULTS The AB has larger elastic moduli than the PB ( P < .0001) in the toe region (median, 2.73 MPa [interquartile range, 1.1-5.6 MPa] vs 0.65 MPa [0.44-1.5 MPa]) and the linear region (13.77 MPa [4.8-40.7 MPa] vs 1.96 MPa [0.58-9.3 MPa]). The AB demonstrated larger stress values, stronger collagen alignment, and more uniform collagen organization during stress-relaxation. PB collagen fibers were more disorganized than the AB during the zero ( P = .046), transitional ( P = .011), and linear ( P = .007) regions of the stress-strain curve. Both UCL bundles exhibited very small changes in collagen alignment (SD of the angle of polarization) with load. CONCLUSION The AB of the UCL is stiffer and stronger, with more strongly aligned and more uniformly oriented collagen fibers, than the PB. The small changes in collagen alignment indicate that the UCL response to load is due more to its static collagen organization than to dynamic changes in collagen alignment. CLINICAL RELEVANCE The UCL collagen organization may explain its susceptibility to injury with repetitive valgus loads.
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Affiliation(s)
- Matthew V Smith
- Department of Orthopaedic Surgery, Washington University, St Louis, Missouri, USA
| | - Ryan M Castile
- Department of Mechanical Engineering and Materials Science, Washington University, St Louis, Missouri, USA
| | - Robert H Brophy
- Department of Orthopaedic Surgery, Washington University, St Louis, Missouri, USA
| | - Ashvin Dewan
- Methodist Orthopedic Specialists of Texas, Sugar Land, Texas, USA
| | - David Bernholt
- Department of Orthopaedic Surgery, Washington University, St Louis, Missouri, USA
| | - Spencer P Lake
- Department of Orthopaedic Surgery, Washington University, St Louis, Missouri, USA.,Department of Mechanical Engineering and Materials Science, Washington University, St Louis, Missouri, USA
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22
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Eekhoff JD, Fang F, Kahan LG, Espinosa G, Cocciolone AJ, Wagenseil JE, Mecham RP, Lake SP. Functionally Distinct Tendons From Elastin Haploinsufficient Mice Exhibit Mild Stiffening and Tendon-Specific Structural Alteration. J Biomech Eng 2018; 139:2654667. [PMID: 28916838 DOI: 10.1115/1.4037932] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2017] [Indexed: 12/23/2022]
Abstract
Elastic fibers are present in low quantities in tendon, where they are located both within fascicles near tenocytes and more broadly in the interfascicular matrix (IFM). While elastic fibers have long been known to be significant in the mechanics of elastin-rich tissue (i.e., vasculature, skin, lungs), recent studies have suggested a mechanical role for elastic fibers in tendons that is dependent on specific tendon function. However, the exact contribution of elastin to properties of different types of tendons (e.g., positional, energy-storing) remains unknown. Therefore, this study purposed to evaluate the role of elastin in the mechanical properties and collagen alignment of functionally distinct supraspinatus tendons (SSTs) and Achilles tendons (ATs) from elastin haploinsufficient (HET) and wild type (WT) mice. Despite the significant decrease in elastin in HET tendons, a slight increase in linear stiffness of both tendons was the only significant mechanical effect of elastin haploinsufficiency. Additionally, there were significant changes in collagen nanostructure and subtle alteration to collagen alignment in the AT but not the SST. Hence, elastin may play only a minor role in tendon mechanical properties. Alternatively, larger changes to tendon mechanics may have been mitigated by developmental compensation of HET tendons and/or the role of elastic fibers may be less prominent in smaller mouse tendons compared to the larger bovine and human tendons evaluated in previous studies. Further research will be necessary to fully elucidate the influence of various elastic fiber components on structure-function relationships in functionally distinct tendons.
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Affiliation(s)
- Jeremy D Eekhoff
- Department of Biomedical Engineering, Washington University in St. Louis One Brookings Drive, St. Louis, MO 63130
| | - Fei Fang
- Department of Mechanical Engineering and Materials Science, Washington University in St. Louis, One Brookings Drive, St. Louis, MO 63130
| | - Lindsey G Kahan
- Department of Biomedical Engineering, Washington University in St. Louis, One Brookings Drive, St. Louis, MO 63130
| | - Gabriela Espinosa
- Department of Biomedical Engineering, Washington University in St. Louis, One Brookings Drive, St. Louis, MO 63130
| | - Austin J Cocciolone
- Department of Biomedical Engineering, Washington University in St. Louis, One Brookings Drive, St. Louis, MO 63130
| | - Jessica E Wagenseil
- Department of Mechanical Engineering and Materials Science, Washington University in St. Louis, One Brookings Drive, St. Louis, MO 63130
| | - Robert P Mecham
- Department of Cell Biology and Physiology, Washington University in St. Louis, 660 South Euclid Avenue, St. Louis, MO 63110
| | - Spencer P Lake
- Department of Mechanical Engineering and Materials Science, Washington University in St. Louis, One Brookings Drive, St. Louis, MO 63130.,Department of Biomedical Engineering, Washington University in St. Louis, One Brookings Drive, St. Louis, MO 63130.,Department of Orthopaedic Surgery, Washington University in St. Louis, One Brookings Drive, St. Louis, MO 63130 e-mail:
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Cronin TW, Garcia M, Gruev V. Multichannel spectrometers in animals. BIOINSPIRATION & BIOMIMETICS 2018; 13:021001. [PMID: 29313524 DOI: 10.1088/1748-3190/aaa61b] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Multispectral, hyperspectral, polarimetric, and other types of multichannel imaging spectrometers are coming into common use for a variety of applications, including remote sensing, material identification, forensics, and medical diagnosis. These instruments are often bulky and intolerant of field abuse, so designing compact, reliable, portable, and robust devices is a priority. In contrast to most engineering designs, animals have been building compact and robust multichannel imaging systems for millennia-their eyes. Biological sensors arise by evolution, of course, and are not designed 'for' a particular use; they exist because the creatures that were blessed with useful mutations were better able to survive and reproduce than their competitors. While this is an inefficient process for perfecting a sensor, it brings unexpected innovations and novel concepts into visual system design-concepts that may be useful in the inspiration of new engineered solutions to problematic challenges, like the ones mentioned above. Here, we review a diversity of multichannel visual systems from both vertebrate and invertebrate animals, considering the receptor molecules and cells, spectral sensitivity and its tuning, and some aspects of the higher-level processing systems used to shape spectral (and polarizational) channels in vision. The eyes of mantis shrimps are presented as potential models for biomimetic multichannel imaging systems. We end with a description of a bioinspired, newly developed multichannel spectral/polarimetric imaging system based on mantis shrimp vision that is highly adaptable to field application.
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Affiliation(s)
- Thomas W Cronin
- Department of Biological Sciences, University of Maryland Baltimore County, Baltimore, MD 21250, United States of America
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Biomechanics of human parietal pleura in uniaxial extension. J Mech Behav Biomed Mater 2017; 75:330-335. [DOI: 10.1016/j.jmbbm.2017.07.044] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2017] [Revised: 07/21/2017] [Accepted: 07/28/2017] [Indexed: 12/17/2022]
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Noailles T, Boisrenoult P, Sanchez M, Beaufils P, Pujol N. Torsional Appearance of the Anterior Cruciate Ligament Explaining "Ribbon" and Double-Bundle Concepts: A Cadaver-based Study. Arthroscopy 2017; 33:1703-1709. [PMID: 28865572 DOI: 10.1016/j.arthro.2017.03.019] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/11/2016] [Revised: 02/27/2017] [Accepted: 03/14/2017] [Indexed: 02/02/2023]
Abstract
PURPOSE To investigate the effect of the anterior cruciate ligament (ACL) torsion in 90° knee flexion on the morphological appearance of the ACL. METHODS Sixty knees from fresh frozen anatomical specimens were dissected. Eighteen knees were excluded according to selection criteria (torn ACL, mucoid degeneration of the ACL, arthritic lesions of the notch, or knees harboring synovial inflammatory pathologies). After the removal of the synovial membrane, the morphology of the ligamentous fibers of the ACL and the twist were analyzed. Twisting of the ACL was measured using a goniometer in 90° knee flexion and defined by the angle of external rotation of the femur on the axis of the tibia required to visualize a flat ACL. The orientation of tibial and femoral footprint was described in a coronal plane for the tibia and a sagittal plane for the femur. RESULTS In the 42 knees that were finally included, the ACL was always displayed as a single ribbon-like structure. The torsion of the fibers was on average 83.6° (± 9.4°) in 90° knee flexion. The twisting could be explained by the different orientations of the femoral (vertical in a sagittal plane) and tibial (horizontal in a coronal plane) footprints. An intraligamentous proximal cleavage area was encountered in 11 cases (i.e., 26%). CONCLUSIONS The ACL is a twisted structure with 83.6° of external torsion of fibers in 90° knee flexion. It is the torsion in the fibers, due to the relative position of bone insertions, which gives the ACL the appearance of being double bundle. CLINICAL RELEVANCE The concept of the torsional flat structure of the native ACL may be of importance during ACL reconstruction, both in terms of graft choice (flat rather than cylindrical) and of technical positioning (torsion).
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Affiliation(s)
- Thibaut Noailles
- Service d'Orthopédie Traumatologie, Centre Hospitalier de Versailles, Hôpital André Mignot, Le Chesnay, France.
| | - Philippe Boisrenoult
- Service d'Orthopédie Traumatologie, Centre Hospitalier de Versailles, Hôpital André Mignot, Le Chesnay, France
| | - Matthieu Sanchez
- Service d'Orthopédie Traumatologie, Centre Hospitalier de Versailles, Hôpital André Mignot, Le Chesnay, France
| | - Philippe Beaufils
- Service d'Orthopédie Traumatologie, Centre Hospitalier de Versailles, Hôpital André Mignot, Le Chesnay, France
| | - Nicolas Pujol
- Service d'Orthopédie Traumatologie, Centre Hospitalier de Versailles, Hôpital André Mignot, Le Chesnay, France
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Zhao L, Lee PV, Ackland DC, Broom ND, Thambyah A. Microstructure Variations in the Soft-Hard Tissue Junction of the Human Anterior Cruciate Ligament. Anat Rec (Hoboken) 2017; 300:1547-1559. [DOI: 10.1002/ar.23608] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2016] [Revised: 03/21/2017] [Accepted: 04/06/2017] [Indexed: 01/18/2023]
Affiliation(s)
- Lei Zhao
- Experimental Tissue Mechanics Laboratory; Department of Chemical and Materials Engineering, University of Auckland; Auckland New Zealand
| | - Peter V.S. Lee
- Department of Biomedical Engineering; University of Melbourne; Victoria Australia
| | - David C. Ackland
- Department of Biomedical Engineering; University of Melbourne; Victoria Australia
| | - Neil D. Broom
- Experimental Tissue Mechanics Laboratory; Department of Chemical and Materials Engineering, University of Auckland; Auckland New Zealand
| | - Ashvin Thambyah
- Experimental Tissue Mechanics Laboratory; Department of Chemical and Materials Engineering, University of Auckland; Auckland New Zealand
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Lee W, Rahman H, Kersh ME, Toussaint KC. Application of quantitative second-harmonic generation microscopy to posterior cruciate ligament for crimp analysis studies. JOURNAL OF BIOMEDICAL OPTICS 2017; 22:46009. [PMID: 28451692 DOI: 10.1117/1.jbo.22.4.046009] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/02/2017] [Accepted: 04/11/2017] [Indexed: 05/03/2023]
Abstract
We use second-harmonic generation (SHG) microscopy to quantitatively characterize collagen fiber crimping in the posterior cruciate ligament (PCL). The obtained SHG images are utilized to define three distinct categories of crimp organization in the PCL. Using our previously published spatial-frequency analysis, we develop a simple algorithm to quantitatively distinguish the various crimp patterns. In addition, SHG microscopy reveals both the three-dimensional structural variation in some PCL crimp patterns as well as an underlying helicity in these patterns that have mainly been observed using electron microscopy. Our work highlights how SHG microscopy could potentially be used to link the fibrous structural information in the PCL to its mechanical properties.
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Affiliation(s)
- Woowon Lee
- University of Illinois at Urbana-Champaign, Department of Mechanical Science and Engineering, Urbana, Illinois, United StatesbUniversity of Illinois at Urbana-Champaign, PROBE Lab, Urbana, Illinois, United States
| | - Hafizur Rahman
- University of Illinois at Urbana-Champaign, Department of Mechanical Science and Engineering, Urbana, Illinois, United States
| | - Mariana E Kersh
- University of Illinois at Urbana-Champaign, Department of Mechanical Science and Engineering, Urbana, Illinois, United States
| | - Kimani C Toussaint
- University of Illinois at Urbana-Champaign, Department of Mechanical Science and Engineering, Urbana, Illinois, United StatesbUniversity of Illinois at Urbana-Champaign, PROBE Lab, Urbana, Illinois, United StatescUniversity of Illinois at Urbana-Champaign, Department of Electrical and Computer Engineering, Urbana, Illinois, United StatesdUniversity of Illinois at Urbana-Champaign, Department of Bioengineering, Urbana, Illinois, United States
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Miller RM, Rahnemai-Azar AA, Sürer L, Arilla FV, Fu FH, Debski RE, Musahl V. Tensile properties of a split quadriceps graft for ACL reconstruction. Knee Surg Sports Traumatol Arthrosc 2017; 25:1249-1254. [PMID: 26869030 DOI: 10.1007/s00167-016-4019-z] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/06/2015] [Accepted: 01/20/2016] [Indexed: 01/14/2023]
Abstract
PURPOSE Anatomic double-bundle ACL reconstruction can be performed using different grafts, such as quadriceps tendon. Grafts can be split in either coronal or sagittal planes to approximate the two bundles of the native ACL, but it is unknown whether a difference exists in the graft tensile properties depending on splitting plane. The purpose of this study was to evaluate the tensile properties of split human quadriceps tendon-bone grafts. METHODS Twenty full-thickness quadriceps tendon-bone grafts were prepared to mimic grafts for double-bundle ACL reconstruction. Ten grafts were split in the sagittal plane, and ten were split in the coronal plane. Each graft underwent cyclic creep testing and load-to-failure testing to compare creep, ultimate load, ultimate elongation, stiffness, and tangent modulus between splitting planes. All parameters were compared between splitting groups (significance p < 0.05). RESULTS Lateral halves of grafts split in the sagittal plane exhibited a percent creep of 42.5 ± 12.4 %, ultimate load of 445 ± 210 N, ultimate elongation of 7.3 ± 1.9 mm, stiffness of 75.7 ± 19.9 N/mm, and tangent modulus of 174.0 ± 99.8 MPa. No differences were found between halves within split tendons or between splitting planes (n.s.). CONCLUSIONS Overall, splitting quadriceps tendon grafts for anatomic double-bundle ACL reconstruction results in similar tensile properties regardless of splitting plane. Surgeons can split quadriceps tendon in either splitting plane, but should take care to preserve fibres as much as possible. This study provides data that support the use of both coronal and sagittal splits of quadriceps tendons for anatomic double-bundle ACL reconstruction.
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Affiliation(s)
- R Matthew Miller
- Orthopaedic Robotics Laboratory, University of Pittsburgh, 408 Center for Bioengineering, 300 Technology Drive, 306 CNBIO, Pittsburgh, PA, 15219, USA
- Department of Bioengineering, Swanson School of Engineering, University of Pittsburgh, 300 Technology Drive, 306 CNBIO, Pittsburgh, PA, 15219, USA
| | - Amir Ata Rahnemai-Azar
- Orthopaedic Robotics Laboratory, University of Pittsburgh, 408 Center for Bioengineering, 300 Technology Drive, 306 CNBIO, Pittsburgh, PA, 15219, USA
- Department of Bioengineering, Swanson School of Engineering, University of Pittsburgh, 300 Technology Drive, 306 CNBIO, Pittsburgh, PA, 15219, USA
- Department of Orthopaedic Surgery, University of Pittsburgh, 3471 Fifth Avenue, 1010 Kaufmann Building, Pittsburgh, PA, 15213, USA
| | - Levent Sürer
- Orthopaedic Robotics Laboratory, University of Pittsburgh, 408 Center for Bioengineering, 300 Technology Drive, 306 CNBIO, Pittsburgh, PA, 15219, USA
- Department of Orthopaedic Surgery, University of Pittsburgh, 3471 Fifth Avenue, 1010 Kaufmann Building, Pittsburgh, PA, 15213, USA
| | - Fabio V Arilla
- Orthopaedic Robotics Laboratory, University of Pittsburgh, 408 Center for Bioengineering, 300 Technology Drive, 306 CNBIO, Pittsburgh, PA, 15219, USA
- Department of Orthopaedic Surgery, University of Pittsburgh, 3471 Fifth Avenue, 1010 Kaufmann Building, Pittsburgh, PA, 15213, USA
| | - Freddie H Fu
- Orthopaedic Robotics Laboratory, University of Pittsburgh, 408 Center for Bioengineering, 300 Technology Drive, 306 CNBIO, Pittsburgh, PA, 15219, USA
- Department of Orthopaedic Surgery, University of Pittsburgh, 3471 Fifth Avenue, 1010 Kaufmann Building, Pittsburgh, PA, 15213, USA
| | - Richard E Debski
- Orthopaedic Robotics Laboratory, University of Pittsburgh, 408 Center for Bioengineering, 300 Technology Drive, 306 CNBIO, Pittsburgh, PA, 15219, USA.
- Department of Bioengineering, Swanson School of Engineering, University of Pittsburgh, 300 Technology Drive, 306 CNBIO, Pittsburgh, PA, 15219, USA.
- Department of Orthopaedic Surgery, University of Pittsburgh, 3471 Fifth Avenue, 1010 Kaufmann Building, Pittsburgh, PA, 15213, USA.
| | - Volker Musahl
- Orthopaedic Robotics Laboratory, University of Pittsburgh, 408 Center for Bioengineering, 300 Technology Drive, 306 CNBIO, Pittsburgh, PA, 15219, USA
- Department of Bioengineering, Swanson School of Engineering, University of Pittsburgh, 300 Technology Drive, 306 CNBIO, Pittsburgh, PA, 15219, USA
- Department of Orthopaedic Surgery, University of Pittsburgh, 3471 Fifth Avenue, 1010 Kaufmann Building, Pittsburgh, PA, 15213, USA
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Skelley NW, Castile RM, Cannon PC, Weber CI, Brophy RH, Lake SP. Regional Variation in the Mechanical and Microstructural Properties of the Human Anterior Cruciate Ligament. Am J Sports Med 2016; 44:2892-2899. [PMID: 27456027 DOI: 10.1177/0363546516654480] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
BACKGROUND The anteromedial (AM) bundle of the anterior cruciate ligament (ACL) has a higher modulus and failure stress than does the posterolateral (PL) bundle. However, it is unknown how these properties vary within each bundle. PURPOSE To quantify mechanical and microstructural properties of samples within ACL bundles to elucidate any regional variation across the ligament. We hypothesized that there are no differences within each bundle in contrast to cross-bundle variation. STUDY DESIGN Descriptive laboratory study. METHODS Sixteen human ACLs were dissected into AM and PL bundles. Three samples were taken from each bundle in an ordered sequence from AM (region 1 AM bundle) to PL (region 6 PL bundle). Each sample was tested in uniaxial tension, using quantitative polarized light imaging (QPLI) to quantify collagen fiber alignment. After preconditioning, samples were subjected to a stress-relaxation (SR) test followed by quasistatic ramp-to-failure (RF). Peak and equilibrium stress values were computed from the SR test and modulus quantified in the toe- and linear-regions of the RF. QPLI values describing collagen orientation (angle of polarization [AoP]) and strength of alignment (degree of linear polarization [DoLP]) were computed for the SR test and at points corresponding to the zero, transition point, and linear region of the RF. RESULTS Toe- and linear-region modulus values decreased from region 1 to 6. Slopes of regression lines increased for the average DoLP during RF, with significance at higher strains. The standard deviation of AoP values decreased during RF, indicating tighter distribution of orientation angles, with significant correlations at all points of the RF. During SR, stress values uniformly decreased but did not show significant linear regression by region. DoLP and AoP values changed slightly during SR and demonstrated significant linear variation by region at both peak and equilibrium points. CONCLUSION Most microstructural and material properties evaluated in this study appear to follow a linear gradient across the ACL, rather than varying by bundle. CLINICAL RELEVANCE This AM-to-PL variation provides a more accurate description of functional tissue anatomy and can be used to assess and guide techniques of ACL reconstruction.
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Affiliation(s)
- Nathan W Skelley
- Department of Orthopaedic Surgery, Barnes-Jewish Hospital/Washington University in St Louis School of Medicine, St Louis, Missouri, USA
| | - Ryan M Castile
- Department of Mechanical Engineering and Materials Science, Washington University in St Louis, St Louis, Missouri, USA
| | - Paul C Cannon
- Monsanto Global Production Technology Analytics, St Louis, Missouri, USA
| | - Christian I Weber
- Department of Biomedical Engineering, Washington University in St Louis, St Louis, Missouri, USA
| | - Robert H Brophy
- Department of Orthopaedic Surgery, Barnes-Jewish Hospital/Washington University in St Louis School of Medicine, St Louis, Missouri, USA
| | - Spencer P Lake
- Department of Orthopaedic Surgery, Barnes-Jewish Hospital/Washington University in St Louis School of Medicine, St Louis, Missouri, USA .,Department of Mechanical Engineering and Materials Science, Washington University in St Louis, St Louis, Missouri, USA.,Department of Biomedical Engineering, Washington University in St Louis, St Louis, Missouri, USA
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Wright JO, Skelley NW, Schur RP, Castile RM, Lake SP, Brophy RH. Microstructural and Mechanical Properties of the Posterior Cruciate Ligament: A Comparison of the Anterolateral and Posteromedial Bundles. J Bone Joint Surg Am 2016; 98:1656-1664. [PMID: 27707852 DOI: 10.2106/jbjs.16.00032] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
BACKGROUND The microstructural organization (collagen fiber alignment) of the posterior cruciate ligament (PCL), which likely corresponds with its functional properties, has only been described qualitatively in the literature, to our knowledge. The goal of this study was to quantify the tensile mechanical and microstructural properties of the PCL and compare these qualities between the anterolateral and posteromedial bundles. METHODS Twenty-two knee specimens from 13 donors (8 male and 5 female; mean age [and standard deviation] at the time of death, 43.0 ± 4.1 years; mean body mass index, 30.0 ± 6.7 kg/m2) were dissected to isolate the PCL, and each bundle was split into 3 regions. Mechanical testing of each regional sample consisted of preconditioning followed by a ramp-and-hold stress-relaxation test and a quasi-static ramp-to-failure test. Microstructural analysis was performed with use of a high-resolution, division-of-focal-plane polarization camera to evaluate the average direction of collagen orientation and the degree to which the collagen fibers were aligned in that direction. Results were compared between the anterolateral and posteromedial bundles and across the regions of each bundle. RESULTS The anterolateral and posteromedial bundles demonstrated largely equivalent mechanical and microstructural properties. Elastic moduli in the toe and linear regions were not different; however, the posteromedial bundle did show significantly more stress relaxation (p = 0.004). There were also few differences in microstructural properties between bundles, which again were seen only in stress relaxation. Comparing regions within each bundle, several mechanical and microstructural parameters showed significant relationships across the posteromedial bundle, following a gradient of decreasing strength and alignment from anterior to posterior. CONCLUSIONS The PCL has relatively homogenous microstructural and mechanical properties, with few differences between the anterolateral and posteromedial bundles. This finding suggests that distinct functions of the PCL bundles result primarily from size and anatomical location rather than from differences in these properties. CLINICAL RELEVANCE These properties of the PCL can be used to assess the utility of graft choices and operative techniques for PCL reconstruction and may partly explain limited differences in the outcomes of single-bundle compared with double-bundle reconstruction techniques for the PCL.
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Affiliation(s)
- Jon O Wright
- Departments of Orthopaedic Surgery (J.O.W., N.W.S., S.P.L, and R.H.B.), Mechanical Engineering and Materials Science (R.P.S., R.M.C., and S.P.L.), and Biomedical Engineering (S.P.L.), Washington University in St. Louis, St. Louis, Missouri Department of Orthopaedic Surgery, Beaumont Health, Royal Oak, Michigan
| | - Nathan W Skelley
- Departments of Orthopaedic Surgery (J.O.W., N.W.S., S.P.L, and R.H.B.), Mechanical Engineering and Materials Science (R.P.S., R.M.C., and S.P.L.), and Biomedical Engineering (S.P.L.), Washington University in St. Louis, St. Louis, Missouri
| | - Reid P Schur
- Departments of Orthopaedic Surgery (J.O.W., N.W.S., S.P.L, and R.H.B.), Mechanical Engineering and Materials Science (R.P.S., R.M.C., and S.P.L.), and Biomedical Engineering (S.P.L.), Washington University in St. Louis, St. Louis, Missouri
| | - Ryan M Castile
- Departments of Orthopaedic Surgery (J.O.W., N.W.S., S.P.L, and R.H.B.), Mechanical Engineering and Materials Science (R.P.S., R.M.C., and S.P.L.), and Biomedical Engineering (S.P.L.), Washington University in St. Louis, St. Louis, Missouri
| | - Spencer P Lake
- Departments of Orthopaedic Surgery (J.O.W., N.W.S., S.P.L, and R.H.B.), Mechanical Engineering and Materials Science (R.P.S., R.M.C., and S.P.L.), and Biomedical Engineering (S.P.L.), Washington University in St. Louis, St. Louis, Missouri
| | - Robert H Brophy
- Departments of Orthopaedic Surgery (J.O.W., N.W.S., S.P.L, and R.H.B.), Mechanical Engineering and Materials Science (R.P.S., R.M.C., and S.P.L.), and Biomedical Engineering (S.P.L.), Washington University in St. Louis, St. Louis, Missouri
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Castile RM, Skelley NW, Babaei B, Brophy RH, Lake SP. Microstructural properties and mechanics vary between bundles of the human anterior cruciate ligament during stress-relaxation. J Biomech 2016; 49:87-93. [DOI: 10.1016/j.jbiomech.2015.11.016] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2015] [Revised: 11/13/2015] [Accepted: 11/17/2015] [Indexed: 11/29/2022]
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