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Fung AK, Li Y, Wang J, Leahy TP, Shetye SS, Liu XS, Soslowsky LJ. Long-Term Effects of Reproduction and Lactation on the Rat Supraspinatus Tendon and Proximal Humerus. J Biomech Eng 2024; 146:060905. [PMID: 37792487 PMCID: PMC11005856 DOI: 10.1115/1.4063628] [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: 06/29/2023] [Revised: 09/12/2023] [Accepted: 09/25/2023] [Indexed: 10/06/2023]
Abstract
During pregnancy and breastfeeding, women undergo hormonal fluctuations required for fetal development, parturition, and infant growth. These changes have secondary consequences on the maternal musculoskeletal system, increasing the risk for joint pain and osteoporosis. Though hormone levels return to prepregnancy levels postpartum, women may experience lasting musculoskeletal pain. Sex disparities exist in the prevalence of musculoskeletal disorders, but it remains unclear how reproductive history may impact sex differences. Specifically, the effects of both reproductive history and sex on the rotator cuff have not been studied. Pregnancy and lactation affect bone microstructure, suggesting possible impairments at the enthesis of rotator cuff tendons, where tears commonly occur. Therefore, our objective was to evaluate how reproductive history affects sex differences of the supraspinatus tendon and proximal humerus using male, virgin female, and female rats with a history of reproduction (referred to as reproductive females). We hypothesized tendon mechanical properties and humeral bone microstructure would be inferior in reproductive females compared to virgin females. Results showed sex differences independent of reproductive history, including greater tendon midsubstance modulus but lower subchondral bone mineral density (BMD) in females. When considering reproductive history, reproductive rats exhibited reduced tendon insertion site modulus and trabecular bone micro-architecture compared to virgin females with no differences from males. Overall, our study identified long-term changes in supraspinatus tendon mechanical and humeral trabecular bone properties that result following pregnancy and lactation, highlighting the importance of considering reproductive history in investigations of sex differences in the physiology and pathology of rotator cuff injuries.
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Affiliation(s)
- Ashley K. Fung
- McKay Orthopaedic Research Laboratory, Department of Orthopaedic Surgery, University of Pennsylvania,Philadelphia, PA 19104; Department of Bioengineering, University of Pennsylvania,Philadelphia, PA 19104
| | - Yihan Li
- McKay Orthopaedic Research Laboratory, Department of Orthopaedic Surgery, University of Pennsylvania,Philadelphia, PA 19104; Department of Bioengineering, University of Pennsylvania,Philadelphia, PA 19104
- University of Pennsylvania
| | - Jasmine Wang
- McKay Orthopaedic Research Laboratory, Department of Orthopaedic Surgery, University of Pennsylvania,Philadelphia, PA 19104; Department of Bioengineering, University of Pennsylvania,Philadelphia, PA 19104
- University of Pennsylvania
| | - Thomas P. Leahy
- McKay Orthopaedic Research Laboratory, Department of Orthopaedic Surgery, University of Pennsylvania,Philadelphia, PA 19104; Department of Bioengineering, University of Pennsylvania,Philadelphia, PA 19104
- University of Pennsylvania
| | - Snehal S. Shetye
- McKay Orthopaedic Research Laboratory, Department of Orthopaedic Surgery, University of Pennsylvania, Philadelphia, PA 19104
| | - X. Sherry Liu
- McKay Orthopaedic Research Laboratory, Department of Orthopaedic Surgery, University of Pennsylvania,332A Stemmler Hall, Philadelphia, PA 19104-6081; Department of Bioengineering, University of Pennsylvania, 3450 Hamilton Walk, Philadelphia, PA 19104-6081
| | - Louis J. Soslowsky
- McKay Orthopaedic Research Laboratory, Department of Orthopaedic Surgery, University of Pennsylvania,307A Stemmler Hall, Philadelphia, PA 19104-6081; Department of Bioengineering, University of Pennsylvania, 3450 Hamilton Walk, Philadelphia, PA 19104-6081
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Hartman H, Cacace A, Leatherman H, Ashkani-Esfahani S, Guss D, Waryasz G, DiGiovanni CW, Gianakos AL. Gender Differences in Achilles Tendon Ruptures-A Retrospective Study and a Review of the Literature. J Foot Ankle Surg 2024:S1067-2516(24)00087-5. [PMID: 38763172 DOI: 10.1053/j.jfas.2024.04.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/14/2023] [Revised: 04/21/2024] [Accepted: 04/22/2024] [Indexed: 05/21/2024]
Abstract
Achilles tendon ruptures are common injuries typically sustained during sport with higher incidence in men, though little is understood regarding sex-specific risk factors or outcomes following injury management. This cross-sectional clinical study and systematic review aimed to examine sex-specific Achilles tendon rupture incidence and outcomes following intervention. This study included patients who sustained a rupture between 2011-2021, were ≥18 years old, and who had a minimum follow-up of at least six months, and evaluated age, sex, sport involvement, mechanism of injury, and postoperative complications and revision. Separately, a systematic literature review in the PubMed, EMBASE, and Cochrane databases was performed. A total of 705 male and 158 female patients were included in this retrospective study. 71.1% of men and 52.5% of women sustained a sports-related rupture (p < .001), with sport involvement demonstrating a positive correlation with revision rate (coefficient = 0.09, p = .02). A total of 21 studies with 250,907 patients (87,514 male, 35,792 female) were included in the systematic review. All studies revealed an increased incidence of ATR in men. Functional outcomes were worse in women, and female sex was an independent risk factor for postoperative complications and need for revision surgery. This study demonstrated a higher incidence of sports-related ATR in men than women, likely related to their higher ball sport participation. Although the retrospective analysis did not find a significant difference in complication or revision rates, the systematic review demonstrates poorer functional outcomes, with increased likelihood for postoperative complication and revision surgery in women as compared to men.
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Affiliation(s)
- Hayden Hartman
- DeBusk College of Osteopathic Medicine, Lincoln Memorial University, Knoxville, TN.
| | - Alexis Cacace
- Foot and Ankle Research and Innovation Lab (FARIL), Department of Orthopaedic Surgery, Massachusetts General Hospital, Harvard Medical School, Boston, MA
| | - Hadley Leatherman
- Foot and Ankle Research and Innovation Lab (FARIL), Department of Orthopaedic Surgery, Massachusetts General Hospital, Harvard Medical School, Boston, MA
| | - Soheil Ashkani-Esfahani
- Foot and Ankle Research and Innovation Lab (FARIL), Department of Orthopaedic Surgery, Massachusetts General Hospital, Harvard Medical School, Boston, MA; Foot and Ankle Center, Department of Orthopaedic Surgery, Massachusetts General Hospital, Newton Wellesley Hospital, Harvard Medical School, Boston, MA
| | - Daniel Guss
- Foot and Ankle Research and Innovation Lab (FARIL), Department of Orthopaedic Surgery, Massachusetts General Hospital, Harvard Medical School, Boston, MA; Foot and Ankle Center, Department of Orthopaedic Surgery, Massachusetts General Hospital, Newton Wellesley Hospital, Harvard Medical School, Boston, MA
| | - Gregory Waryasz
- Foot and Ankle Research and Innovation Lab (FARIL), Department of Orthopaedic Surgery, Massachusetts General Hospital, Harvard Medical School, Boston, MA; Foot and Ankle Center, Department of Orthopaedic Surgery, Massachusetts General Hospital, Newton Wellesley Hospital, Harvard Medical School, Boston, MA
| | - Christopher W DiGiovanni
- Foot and Ankle Research and Innovation Lab (FARIL), Department of Orthopaedic Surgery, Massachusetts General Hospital, Harvard Medical School, Boston, MA; Foot and Ankle Center, Department of Orthopaedic Surgery, Massachusetts General Hospital, Newton Wellesley Hospital, Harvard Medical School, Boston, MA
| | - Arianna L Gianakos
- Foot and Ankle Research and Innovation Lab (FARIL), Department of Orthopaedic Surgery, Massachusetts General Hospital, Harvard Medical School, Boston, MA; Department of Orthopaedic Surgery, Yale Medicine, Orthopaedics and Rehabilitation, New Haven, CT
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Campbell TM, Godbout C, Trudel G. Achilles tendons change shape after 21 days of bedrest: A crossover study. Ann Phys Rehabil Med 2024; 67:101818. [PMID: 38479113 DOI: 10.1016/j.rehab.2024.101818] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2023] [Revised: 12/12/2023] [Accepted: 12/20/2023] [Indexed: 04/13/2024]
Affiliation(s)
- T Mark Campbell
- Department of Physical Medicine and Rehabilitation, Elisabeth Bruyère Hospital, Ottawa, Ontario, Canada; Department of Cellular and Molecular Medicine, Faculty of Medicine, University of Ottawa, Ottawa, Ontario, Canada; Department of Medicine, The Ottawa Hospital, Ottawa, Ontario, Canada; Bone and Joint Research Laboratory, The Ottawa Hospital Research Institute, Ottawa, Ontario, Canada; Division of Physical Medicine and Rehabilitation, Department of Medicine, Faculty of Medicine, University of Ottawa, Ottawa, Ontario, Canada.
| | - Charles Godbout
- Department of Medicine, The Ottawa Hospital, Ottawa, Ontario, Canada
| | - Guy Trudel
- Department of Medicine, The Ottawa Hospital, Ottawa, Ontario, Canada; Bone and Joint Research Laboratory, The Ottawa Hospital Research Institute, Ottawa, Ontario, Canada; Division of Physical Medicine and Rehabilitation, Department of Medicine, Faculty of Medicine, University of Ottawa, Ottawa, Ontario, Canada; Department of Biochemistry, Microbiology and Immunology, University of Ottawa, Ottawa, Ontario, Canada
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Gianakos AL, Hartman H, Kerkhoffs GMMJ, Calder J, Kennedy JG. Sex differences in biomechanical properties of the Achilles tendon may predispose men to higher risk of injury: A systematic review. J ISAKOS 2024; 9:184-191. [PMID: 37967617 DOI: 10.1016/j.jisako.2023.11.001] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2023] [Revised: 11/05/2023] [Accepted: 11/06/2023] [Indexed: 11/17/2023]
Abstract
IMPORTANCE Men have a higher risk of Achilles tendon (AT) injury, and the impact of morphological and mechanical sex differences may play a role. AIM The aim of this study is to systematically review the literature to determine whether there are sex-specific differences in AT morphological and mechanical properties and analyze how these differences may impact AT injury in both men and women. EVIDENCE REVIEW A systematic literature search of articles published between 2001 and 2021, in the MEDLINE, EMBASE, and Cochrane databases was performed during May 2022 according to PRISMA. The primary outcome measures included sex-related differences in the mechanical and morphological properties of the Achilles tendon. Secondary outcomes included impact of sex on Achilles tendon properties and adaptation. FINDINGS Nineteen studies with a total of 1,143 participants (613 men and 530 women) were included in this systematic review. Men had increased measurements when compared with women in the following: AT length, thickness, cross-sectional area (CSA), stiffness, peak force, loading rate, and voluntary muscle contraction. Women had an increase in CSA deformation, strain, and compliance. CONCLUSIONS AND RELEVANCE Our study demonstrates that men have an increased AT length, thickness, and CSA, indicating that men may be subjected biomechanically to higher loads in their day-to-day activities. In addition, men have lower deformation and compliance properties, along with increased AT stiffness, reducing their capacity to adapt during loading, potentially increasing their risk of injury. LEVEL OF EVIDENCE IV.
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Affiliation(s)
- Arianna L Gianakos
- Department of Orthopaedic Surgery, Yale Medicine Orthopaedics and Rehabilitation, New Haven, CT, 06519, USA
| | - Hayden Hartman
- Lincoln Memorial University, DeBusk College of Osteopathic Medicine, Knoxville, TN, 37932, USA.
| | - Gino M M J Kerkhoffs
- Department of Orthopaedic Surgery and Sports Medicine, Amsterdam Movement Sciences, Amsterdam UMC, Location AMC, University of Amsterdam, Amsterdam, the Netherlands; Academic Center for Evidence-Based Sports Medicine, Amsterdam UMC, Amsterdam, the Netherlands; Amsterdam Collaboration for Health and Safety in Sports, International Olympic Committee Research Center, Amsterdam UMC, Amsterdam, the Netherlands
| | | | - John G Kennedy
- Department of Orthopaedic Surgery, New York University Langone Health, New York, NY, 10002, USA
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Ashton DM, Blaker CL, Hartnell N, Haubruck P, Hefferan SA, Little CB, Clarke EC. Challenging the Perceptions of Human Tendon Allografts: Influence of Donor Age, Sex, Height, and Tendon on Biomechanical Properties. Am J Sports Med 2023; 51:768-778. [PMID: 36594505 DOI: 10.1177/03635465221143385] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
BACKGROUND The use of allograft tendons has increased for primary and revision anterior cruciate ligament reconstruction, but allograft supply is currently limited to a narrow range of tendons and donors up to the age of 65 years. Expanding the range of donors and tendons could help offset an increasing clinical demand. PURPOSE To investigate the effects of donor age, sex, height, and specific tendon on the mechanical properties of a range of human lower leg tendons. STUDY DESIGN Descriptive laboratory study. METHODS Nine tendons were retrieved from 39 fresh-frozen human cadaveric lower legs (35 donors [13 female, 22 male]; age, 49-99 years; height, 57-85 inches [145-216 cm]) including: Achilles tendon, tibialis posterior and anterior, fibularis longus and brevis, flexor and extensor hallucis longus, plantaris, and flexor digitorum longus. Tendons underwent tensile loading to failure measuring cross-sectional area (CSA), maximum load, strain at failure, ultimate tensile strength, and elastic modulus. Results from 332 tendons were analyzed using mixed-effects linear regression, accounting for donor age, sex, height, and weight. RESULTS Mechanical properties were significantly different among tendons and were substantially greater than the effects of donor characteristics. Significant effects of donor sex, age, and height were limited to specific tendons: Achilles tendon, tibialis posterior, and tibialis anterior. All other tendons were unaffected. The Achilles tendon was most influenced by donor variables: greater CSA in men (β = 15.45 mm2; Šidák adjusted P < .0001), decreased maximum load with each year of increased age (β = -17.20 N per year; adjusted P = .0253), and increased CSA (β = 1.92 mm2 per inch; adjusted P < .0001) and maximum load (β = 86.40 N per inch; adjusted P < .0001) with each inch of increased height. CONCLUSION Mechanical properties vary significantly across different human tendons. The effects of donor age, sex, and height are relatively small, are limited to specific tendons, and affect different tendons uniquely. The findings indicate that age negatively affected only the Achilles tendon (maximum load) and challenge the exclusion of donors aged >65 years across all tendon grafts. CLINICAL RELEVANCE The findings support including a broader range of tendons for use as allografts for anterior cruciate ligament reconstruction and reviewing the current exclusion criterion of donors aged >65 years.
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Affiliation(s)
- Dylan M Ashton
- Murray Maxwell Biomechanics Laboratory, Institute of Bone and Joint Research, Kolling Institute; Northern Sydney Local Health District; Sydney Musculoskeletal Health, Faculty of Medicine and Health, University of Sydney, St Leonards, Australia
| | - Carina L Blaker
- Murray Maxwell Biomechanics Laboratory, Institute of Bone and Joint Research, Kolling Institute; Northern Sydney Local Health District; Sydney Musculoskeletal Health, Faculty of Medicine and Health, University of Sydney, St Leonards, Australia
| | | | - Patrick Haubruck
- Heidelberg Trauma Research Group, Centre for Orthopaedics, Trauma Surgery and Spinal Cord Injury, Trauma and Reconstructive Surgery, Heidelberg University Hospital, Heidelberg, Germany.,Raymond Purves Bone and Joint Research Laboratories, Institute of Bone and Joint Research, Kolling Institute; Northern Sydney Local Health District; Sydney Musculoskeletal Health, Faculty of Medicine and Health, University of Sydney, St Leonards, Australia
| | - Samantha A Hefferan
- Murray Maxwell Biomechanics Laboratory, Institute of Bone and Joint Research, Kolling Institute; Northern Sydney Local Health District; Sydney Musculoskeletal Health, Faculty of Medicine and Health, University of Sydney, St Leonards, Australia
| | - Christopher B Little
- Raymond Purves Bone and Joint Research Laboratories, Institute of Bone and Joint Research, Kolling Institute; Northern Sydney Local Health District; Sydney Musculoskeletal Health, Faculty of Medicine and Health, University of Sydney, St Leonards, Australia
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Häußler TC, Kornmayer M, Scheich M, Fischer A, Feichtenschlager CJ, Rohwedder T. Retrospective multicentre evaluation of common calcaneal tendon injuries in 66 cats. Part 1: study population, injury specification and classification. J Feline Med Surg 2023; 25:1098612X221131253. [PMID: 36706012 PMCID: PMC10812052 DOI: 10.1177/1098612x221131253] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
OBJECTIVES The objective of the first part of this retrospective multicentre study was to identify and classify common calcaneal tendon (CCT) injuries in a study population of 66 cats. METHODS The medical records of five different small animal referral centres and veterinary teaching hospitals between 2010 and 2020 were reviewed. In addition to patient-specific data, CCT injuries were characterised in detail. Diagnostic modalities and further comorbidities were recorded. RESULTS Sixty-six cats met the inclusion criteria. The mean age of the cats was 7.5 years (range 0.5-16.3) and their mean body weight (BW) was 4.6 kg (range 1.5-9.0). Thirty-four spayed females (51.5%), five intact females (7.6%) and 27 castrated males (40.9%) were included. Most cases involved closed injuries of the CCT (69.7%). Twenty-one of 46 cats had closed atraumatic injuries (45.7%). Open injuries (30.3%) were most commonly lacerations (65%). Twenty-one injuries were classified as atraumatic (31.8%), whereas 25 were traumatic (37.9%). With every year of age, the odds of having an atraumatic injury increased by a factor of 1.021. Cats with atraumatic injuries had a higher mean BW than cats with traumatic injuries, but the difference was not statistically significant. Acute injuries were recorded in 40.9% of cases, whereas 51.5% of cats had a subacute CCT injury and 7.6% had chronic lesions. Most acute lesions were Meutstege type I injuries (55.6%). Subacute and chronic lesions were more commonly Meutstege type IIc injuries (58.8% and 60%, respectively). Considering all CCT injuries, a Meutstege type IIc injury was most common (53%). CONCLUSIONS AND RELEVANCE The most common type of injury was Meutstege type IIc. Cats with atraumatic injuries had a higher mean BW than cats with traumatic injuries, but the difference was not statistically significant. Older cats more commonly presented with atraumatic CCT injuries.
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Affiliation(s)
- Thomas C Häußler
- Department of Veterinary Clinical Sciences, Small Animal Clinic – Surgery, Justus-Liebig-University, Giessen, Germany
| | - Matthias Kornmayer
- Clinic for Small Animal Surgery and Reproduction, Ludwig-Maximilians-University, Munich, Germany
| | | | | | - Christian J Feichtenschlager
- Department of Veterinary Clinical Sciences, Small Animal Clinic – Surgery, Justus-Liebig-University, Giessen, Germany
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Freedman BR, Adu-Berchie K, Barnum C, Fryhofer GW, Salka NS, Shetye S, Soslowsky LJ. Nonsurgical treatment reduces tendon inflammation and elevates tendon markers in early healing. J Orthop Res 2022; 40:2308-2319. [PMID: 34935170 PMCID: PMC9209559 DOI: 10.1002/jor.25251] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/28/2021] [Revised: 12/07/2021] [Accepted: 12/19/2021] [Indexed: 02/04/2023]
Abstract
Operative treatment is assumed to provide superior outcomes to nonoperative (conservative) treatment following Achilles tendon rupture, however, this remains controversial. This study explores the effect of surgical repair on Achilles tendon healing. Rat Achilles tendons (n = 101) were bluntly transected and were randomized into groups receiving repair or non-repair treatments. By 1 week after injury, repaired tendons had inferior mechanical properties, which continued to 3- and 6-week post-injury, evidenced by decreased dynamic modulus and failure stress. Transcriptomics analysis revealed >7000 differentially expressed genes between repaired and non-repaired tendons after 1-week post-injury. While repaired tendons showed enriched inflammatory gene signatures, non-repaired tendons showed increased tenogenic, myogenic, and mechanosensitive gene signatures, with >200-fold enrichment in Tnmd expression. Analysis of gastrocnemius muscle revealed elevated MMP activity in tendons receiving repair treatment, despite no differences in muscle fiber morphology. Transcriptional regulation analysis highlighted that the highest expressed transcription factors in repaired tendons were associated with inflammation (Nfκb, SpI1, RelA, and Stat1), whereas non-repaired tendons expressed markers associated with tissue development and mechano-activation (Smarca1, Bnc2, Znf521, Fbn1, and Gli3). Taken together, these data highlight distinct differences in healing mechanism occurring immediately following injury and provide insights for new therapies to further augment tendons receiving repaired and non-repaired treatments.
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Affiliation(s)
- Benjamin R Freedman
- McKay Orthopedic Research Laboratory, University of Pennsylvania, Philadelphia, Pennsylvania, USA
- John A Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, Massachusetts, USA
- Wyss Institute for Biologically Inspired Engineering at Harvard University, Boston, Massachusetts, USA
| | - Kwasi Adu-Berchie
- John A Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, Massachusetts, USA
- Wyss Institute for Biologically Inspired Engineering at Harvard University, Boston, Massachusetts, USA
| | - Carrie Barnum
- McKay Orthopedic Research Laboratory, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - George W Fryhofer
- McKay Orthopedic Research Laboratory, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Nabeel S Salka
- McKay Orthopedic Research Laboratory, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Snehal Shetye
- McKay Orthopedic Research Laboratory, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Louis J Soslowsky
- McKay Orthopedic Research Laboratory, University of Pennsylvania, Philadelphia, Pennsylvania, USA
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Abstract
Tendons are collagen-rich musculoskeletal tissues that possess the mechanical strength needed to transfer forces between muscles and bones. The mechanical development and function of tendons are impacted by collagen crosslinks. However, there is a limited understanding of how collagen crosslinking is regulated in tendon during development and aging. Therefore, the objective of the present review was to highlight potential regulators of enzymatic and non-enzymatic collagen crosslinking and how they impact tendon function. The main collagen crosslinking enzymes include lysyl oxidase (LOX) and the lysyl oxidase-like isoforms (LOXL), whereas non-enzymatic crosslinking is mainly mediated by the formation of advanced glycation end products (AGEs). Regulators of the LOX and LOXL enzymes may include mechanical stimuli, mechanotransducive cell signaling pathways, sex hormones, transforming growth factor (TGF)β family, hypoxia, and interactions with intracellular or extracellular proteins. AGE accumulation in tendon is due to diabetic conditions and aging, and can be mediated by diet and mechanical stimuli. The formation of these enzymatic and non-enzymatic collagen crosslinks plays a major role in tendon biomechanics and in the mechanisms of force transfer. A more complete understanding of how enzymatic and non-enzymatic collagen crosslinking is regulated in tendon will better inform tissue engineering and regenerative therapies aimed at restoring the mechanical function of damaged tendons.
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Affiliation(s)
- A.J. Ellingson
- Chemical and Biological Engineering, University of Idaho, Moscow, ID, USA
| | - N.M. Pancheri
- Chemical and Biological Engineering, University of Idaho, Moscow, ID, USA
| | - N.R. Schiele
- Chemical and Biological Engineering, University of Idaho, Moscow, ID, USA,Address for correspondence: Nathan R. Schiele, Chemical and Biological Engineering, University of Idaho, 875 Perimeter Dr. MS 0904, Moscow, ID, USA. Telephone number: 208 8859063
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Leahy T, Nuss C, Evans MK, Fung A, Shetye S, Soslowsky LJ. Achilles Tendon Ruptures in Middle-Aged Rats Heal Poorly Compared With Those in Young and Old Rats [Formula: see text]. Am J Sports Med 2022; 50:170-181. [PMID: 34851182 PMCID: PMC8819270 DOI: 10.1177/03635465211055476] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
BACKGROUND Achilles tendon ruptures are painful and debilitating injuries and are most common in middle-aged patients. There is a lack of understanding of the underlying causes for increased rupture rates in middle-aged patients and how healing outcomes after a rupture might be affected by patient age. Therefore, the objective of this study was to define age-specific Achilles tendon healing by assessing ankle functional outcomes and Achilles tendon mechanical and histological properties after a rupture using a rat model. HYPOTHESIS Rats representing the middle-aged patient population would demonstrate reduced healing capability after an Achilles tendon rupture, as demonstrated by a slower return to baseline ankle functional properties and inferior biomechanical and histological tendon properties. STUDY DESIGN Controlled laboratory study. METHODS Fischer 344 rats were categorized by age to represent young, middle-aged, and old patients, and Achilles tendon ruptures were induced in the right hindlimb. Animals were allowed to heal and were euthanized at 3 or 6 weeks after the injury. In vivo functional assays and ultrasound imaging were performed throughout the healing period, and ex vivo tendon mechanical and histological properties were assessed after euthanasia. RESULTS Rats representing middle-aged patients displayed reduced healing potential compared with the other age groups, as they demonstrated decreased recovery of in vivo functional and ultrasound assessment parameters and inferior mechanical and histological properties after an Achilles tendon rupture. CONCLUSION These findings may help explain the increased rupture rate observed clinically in middle-aged patients by suggesting that there may be altered tendon responses to daily trauma. CLINICAL RELEVANCE The results provide novel data on age-specific healing outcomes after an Achilles tendon rupture, which underscores the importance of considering a patient's age during treatment and expectations for outcomes.
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Affiliation(s)
- Thomas Leahy
- McKay Orthopaedic Laboratory, University of Pennsylvania, Philadelphia, PA, USA
- Department of Bioengineering, University of Pennsylvania, Philadelphia, PA, USA
| | - Courtney Nuss
- McKay Orthopaedic Laboratory, University of Pennsylvania, Philadelphia, PA, USA
| | - Mary Kate Evans
- McKay Orthopaedic Laboratory, University of Pennsylvania, Philadelphia, PA, USA
- Department of Bioengineering, University of Pennsylvania, Philadelphia, PA, USA
| | - Ashley Fung
- McKay Orthopaedic Laboratory, University of Pennsylvania, Philadelphia, PA, USA
- Department of Bioengineering, University of Pennsylvania, Philadelphia, PA, USA
| | - Snehal Shetye
- McKay Orthopaedic Laboratory, University of Pennsylvania, Philadelphia, PA, USA
| | - Louis J. Soslowsky
- McKay Orthopaedic Laboratory, University of Pennsylvania, Philadelphia, PA, USA
- Department of Bioengineering, University of Pennsylvania, Philadelphia, PA, USA
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Bolam SM, Satokar VV, Konar S, Coleman B, Monk AP, Cornish J, Munro JT, Vickers MH, Albert BB, Musson DS. A Maternal High Fat Diet Leads to Sex-Specific Programming of Mechanical Properties in Supraspinatus Tendons of Adult Rat Offspring. Front Nutr 2021; 8:729427. [PMID: 34589513 PMCID: PMC8473632 DOI: 10.3389/fnut.2021.729427] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2021] [Accepted: 08/16/2021] [Indexed: 12/16/2022] Open
Abstract
Background: Over half of women of reproductive age are now overweight or obese. The impact of maternal high-fat diet (HFD) is emerging as an important factor in the development and health of musculoskeletal tissues in offspring, however there is a paucity of evidence examining its effects on tendon. Alterations in the early life environment during critical periods of tendon growth therefore have the potential to influence tendon health that cross the lifespan. We hypothesised that a maternal HFD would alter biomechanical, morphological and gene expression profiles of adult offspring rotator cuff tendon. Materials and Methods: Female Sprague-Dawley rats were randomly assigned to either: control diet (CD; 10% kcal or 43 mg/g from fat) or HFD (45% kcal or 235 mg/g from fat) 14 days prior to mating and throughout pregnancy and lactation. Eight female and male offspring from each maternal diet group were weaned onto a standard chow diet and then culled at postnatal day 100 for tissue collection. Supraspinatus tendons were used for mechanical testing and histological assessment (cellularity, fibre organisation, nuclei shape) and tail tendons were collected for gene expression analysis. Results: A maternal HFD increased the elasticity (Young's Modulus) in the supraspinatus tendon of male offspring. Female offspring tendon biomechanical properties were not affected by maternal HFD. Gene expression of SCX and COL1A1 were reduced in male and female offspring of maternal HFD, respectively. Despite this, tendon histological organisation were similar between maternal diet groups in both sexes. Conclusion: An obesogenic diet during pregnancy increased tendon elasticity in male, but not female, offspring. This is the first study to demonstrate that maternal diet can modulate the biomechanical properties of offspring tendon. A maternal HFD may be an important factor in regulating adult offspring tendon homeostasis that may predispose offspring to developing tendinopathies and adverse tendon outcomes in later life.
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Affiliation(s)
- Scott M. Bolam
- Bone and Joint Laboratory, University of Auckland, Auckland, New Zealand
- Department of Orthopaedic Surgery, Auckland City Hospital, Auckland, New Zealand
| | - Vidit V. Satokar
- Liggins Institute, University of Auckland, Auckland, New Zealand
| | - Subhajit Konar
- Bone and Joint Laboratory, University of Auckland, Auckland, New Zealand
| | - Brendan Coleman
- Department of Orthopaedic Surgery, Middlemore Hospital, Auckland, New Zealand
| | - Andrew Paul Monk
- Department of Orthopaedic Surgery, Auckland City Hospital, Auckland, New Zealand
- Auckland Bioengineering Institute, University of Auckland, Auckland, New Zealand
| | - Jillian Cornish
- Bone and Joint Laboratory, University of Auckland, Auckland, New Zealand
| | - Jacob T. Munro
- Bone and Joint Laboratory, University of Auckland, Auckland, New Zealand
- Department of Orthopaedic Surgery, Auckland City Hospital, Auckland, New Zealand
| | - Mark H. Vickers
- Liggins Institute, University of Auckland, Auckland, New Zealand
| | | | - David S. Musson
- Bone and Joint Laboratory, University of Auckland, Auckland, New Zealand
- Department of Nutrition, University of Auckland, Auckland, New Zealand
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Riggin CN, Rodriguez AB, Weiss SN, Raja HA, Chen M, Schultz SM, Sehgal CM, Soslowsky LJ. Modulation of vascular response after injury in the rat Achilles tendon alters healing capacity. J Orthop Res 2021; 39:2000-2016. [PMID: 32936495 PMCID: PMC7960560 DOI: 10.1002/jor.24861] [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] [Received: 02/20/2020] [Revised: 09/02/2020] [Accepted: 09/14/2020] [Indexed: 02/04/2023]
Abstract
Tendons are relatively hypovascular but become hypervascular during both injury and degeneration. This is due to the angiogenic response, or the formation of new blood vessels, to tissue injury. The objective of this study was to evaluate the effect of vascular modulation in the rat Achilles tendons during healing. Fischer rats received a bilateral Achilles incisional injury followed by local injections of vascular endothelial growth factor (VEGF), anti-VEGF antibody (B20.4-1-1), or saline either early or late during the healing process. Vascular modulation and healing were evaluated using multiple in vivo ultrasound imaging modalities, in vivo functional assessment, and ex vivo measures of tendon compositional and mechanical properties. The late delivery of anti-VEGF antibody, B20, caused a temporary reduction in healing capacity during a time point where vascularity was also decreased, and then an improvement during a later time point where vascularity was increased relative to control. However, VEGF delivery had a minimal impact on healing and vascular changes in both early and late delivery times. This study was the first to evaluate vascular changes using both in vivo imaging methods and ex vivo histological methods, as well as functional and mechanical outcomes associated with these vascular changes. Clinical significance: this study demonstrates that the alteration of vascular response through the delivery of angiogenic growth factors has the ability to alter tendon healing properties.
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Affiliation(s)
- Corinne N Riggin
- McKay Orthopaedic Research Laboratory, University of Pennsylvania, 307A Stemmler Hall, 36 Street & Hamilton Walk, Philadelphia, PA 19104
| | - Ashley B Rodriguez
- McKay Orthopaedic Research Laboratory, University of Pennsylvania, 307A Stemmler Hall, 36 Street & Hamilton Walk, Philadelphia, PA 19104
| | - Stephanie N Weiss
- McKay Orthopaedic Research Laboratory, University of Pennsylvania, 307A Stemmler Hall, 36 Street & Hamilton Walk, Philadelphia, PA 19104
| | - Harina A Raja
- McKay Orthopaedic Research Laboratory, University of Pennsylvania, 307A Stemmler Hall, 36 Street & Hamilton Walk, Philadelphia, PA 19104
| | - Mengcun Chen
- McKay Orthopaedic Research Laboratory, University of Pennsylvania, 307A Stemmler Hall, 36 Street & Hamilton Walk, Philadelphia, PA 19104
| | - Susan M Schultz
- Department of Radiology, University of Pennsylvania, 1 Silverstein, 3400 Spruce Street, Philadelphia, PA 19104
| | - Chandra M Sehgal
- Department of Radiology, University of Pennsylvania, 1 Silverstein, 3400 Spruce Street, Philadelphia, PA 19104
| | - Louis J Soslowsky
- McKay Orthopaedic Research Laboratory, University of Pennsylvania, 307A Stemmler Hall, 36 Street & Hamilton Walk, Philadelphia, PA 19104,Corresponding Author: Louis J Soslowsky, McKay Orthopaedic Research Laboratory, University of Pennsylvania, 307A Stemmler Hall, 36 Street & Hamilton Walk, Philadelphia, PA 19104, , Phone: 215-898-8653, Fax: 215-573-2133
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12
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Counihan M, Leahy T, Nuss C, Newton J, Mohanty S, Soslowsky LJ, Farber D. Limited Scar Resection for Chronic Achilles Tendon Repair: Use of a Rat Model. Am J Sports Med 2021; 49:2707-2715. [PMID: 34197235 PMCID: PMC8653705 DOI: 10.1177/03635465211023096] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
BACKGROUND Achilles tendon rupture diagnosis is frequently missed, leading to the development of a chronic rupture that requires surgical intervention to remove scar tissue and return the elongated Achilles tendon to appropriate functional length. The limited scar resection (LSR) intervention strategy may provide an advantage over other techniques, as it is less invasive and nondestructive to other tissues, although there is little evidence comparing outcomes between intervention strategies. HYPOTHESIS The LSR technique would be a viable treatment option for chronic Achilles tendon ruptures and would perform comparably with a more clinically accepted procedure, the gastrocnemius fascial turndown (GFT), in postintervention functional outcome measures and tendon mechanical and histological properties. STUDY DESIGN Controlled laboratory study. METHODS Chronic Achilles tendon ruptures were induced in the right hindlimb of Sprague-Dawley rats by Achilles tendon transection without repair, immobilization in dorsiflexion, and 5 weeks of cage activity. Animals were randomly divided between the intervention strategy groups (LSR and GFT), received 1 week of immobilization in plantarflexion, and were sacrificed at 3 or 6 weeks postintervention. In vivo functional outcome measures (gait kinetics, passive joint function, tendon vascular perfusion) were quantified during healing, and tendon mechanical and histological properties were assessed postsacrifice. RESULTS When compared with the GFT, the LSR technique elicited a faster return to baseline in gait kinetics, although there were few differences between groups or with healing time in other functional outcome measures (passive joint function and vascular perfusion). Quasi-static mechanical properties were improved with healing in both surgical intervention groups, although only the LSR group showed an improvement in fatigue properties between 3 and 6 weeks postintervention. Histological properties were similar between intervention strategies, except for decreased cellularity in the LSR group at 6 weeks postintervention. CONCLUSION The LSR technique is a viable surgical intervention strategy for a chronic Achilles tendon rupture in a rodent model, and it performs similarly, if not better, when directly compared with a more clinically accepted surgery, the GFT. CLINICAL RELEVANCE This study supports the increased clinical use of the LSR technique for treating chronic Achilles tendon rupture cases.
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Affiliation(s)
- Matthew Counihan
- McKay Orthopaedic Laboratory, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Thomas Leahy
- McKay Orthopaedic Laboratory, University of Pennsylvania, Philadelphia, Pennsylvania, USA
- Department of Bioengineering, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Courtney Nuss
- McKay Orthopaedic Laboratory, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Joseph Newton
- McKay Orthopaedic Laboratory, University of Pennsylvania, Philadelphia, Pennsylvania, USA
- Department of Bioengineering, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Sarthak Mohanty
- McKay Orthopaedic Laboratory, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Louis J. Soslowsky
- McKay Orthopaedic Laboratory, University of Pennsylvania, Philadelphia, Pennsylvania, USA
- Department of Bioengineering, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Daniel Farber
- McKay Orthopaedic Laboratory, University of Pennsylvania, Philadelphia, Pennsylvania, USA
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13
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Elgart B, Pietrosimone LS, Lucero A, Stafford HC, Berkoff DJ. Identifying achilles tendon structure differences by ultrasound tissue characterization in asymptomatic individuals. Scand J Med Sci Sports 2021; 31:1914-1920. [PMID: 34170573 DOI: 10.1111/sms.14003] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2021] [Accepted: 06/17/2021] [Indexed: 02/05/2023]
Abstract
Ultrasound Tissue Characterization (UTC) is a modality that can be utilized to characterize tendon tissue structure using ultrasonographic imaging paired with a computer algorithm to distinguish echo-types. Several studies have demonstrated UTCs ability to distinguish Achilles tendon morphology changes, but no study has established normative data of the Achilles tendon in the general population. The aim of this study was to determine UTC echo-type distribution in the Achilles tendon in an asymptomatic population. UTC scans were completed and analyzed on 508 participants without Achilles tendinopathy. Dedicated UTC-algorithms were used to distinguish and calculate echo-type percentages and the fiber type distribution was compared. The overall sample echo-type percentages demonstrated greater levels of Type I and II echo-types, 65.73% and 32.00%, respectively, and lower levels of Type III and IV echo-types, 1.74% and 0.57%, respectively. In addition, females had lower levels of Echo-type I compared to men and greater levels of echo-type II (p < 0.001). We also found that African-Americans had significantly greater amounts of echo-type I and lesser amounts of echo-type II when compared to Caucasians (p < 0.05). The results of this study create a normative data set for future UTC studies to utilize as a baseline for the evaluation of Achilles tendons. In addition, it demonstrated tendon type differences between sexes and races that need to be accounted for in future studies.
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Affiliation(s)
- Brian Elgart
- University of North Carolina at Chapel Hill School of Medicine, Chapel Hill, NC, USA
| | - Laura S Pietrosimone
- Department of Orthopaedic Surgery, Doctor of Physical Therapy Division, Duke University, Durham, NC, USA
| | - Angela Lucero
- Anesthesiology, Johns Hopkins University, Baltimore, MD, USA
| | | | - David J Berkoff
- Department of Orthopaedics, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
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14
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Khandare S, Smallcomb M, Klein B, Geary C, Simon JC, Vidt ME. Comparison between dry needling and focused ultrasound on the mechanical properties of the rat Achilles tendon: A pilot study. J Biomech 2021; 120:110384. [PMID: 33773298 PMCID: PMC8089046 DOI: 10.1016/j.jbiomech.2021.110384] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2020] [Revised: 02/18/2021] [Accepted: 03/10/2021] [Indexed: 11/25/2022]
Abstract
In the U.S., approximately 14 million tendon and ligament injuries are reported each year. Dry needling (DN) is a conservative treatment introduced to alleviate pain and restore function; however, it is invasive and has mixed success. Focused ultrasound (fUS) is a non-invasive technology that directs ultrasound energy into a well-defined focal volume. fUS induces thermal and/or mechanical bioeffects which can be controlled by the choice of ultrasound parameters. fUS could be an alternative to DN for treatment of tendon injuries, but the bioeffects must be established. Thus, the purpose of this pilot study was to compare the effect of DN and fUS on the mechanical properties and cell morphology of 30 ex vivo rat Achilles tendons. Tendons were randomly assigned to sham, DN, or fUS, with 10 tendons per group. Within each group, 5 tendons were evaluated mechanically, and 5 tendons were analyzed histologically. Elastic modulus in the DN (74.05 ± 15.0 MPa) group was significantly lower than sham (149.84 ± 59.1 MPa; p = 0.0094) and fUS (128.84 ± 28.3 MPa; p = 0.0453) groups. Stiffness in DN (329.05 ± 236.8 N/mm; p = 0.0034) and fUS (315.26 ± 68.9 N/mm; p = 0.0027) groups were significantly lower than sham (786.10 ± 238.7 N/mm) group. Histologically, localized necrosis was observed in 3 out of 5 tendons exposed to fUS, with surrounding tissue unharmed; no evidence of cellular injury was observed in DN or sham groups. These results suggest that fUS preserves the mechanical properties of tendon better than DN. Further studies are needed to evaluate fUS as an alternative, noninvasive treatment modality for tendon injuries.
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Affiliation(s)
- Sujata Khandare
- Biomedical Engineering, Pennsylvania State University, University Park, PA, USA
| | - Molly Smallcomb
- Graduate Program in Acoustics, Pennsylvania State University, University Park, PA, USA
| | - Bailey Klein
- Biomedical Engineering, Pennsylvania State University, University Park, PA, USA
| | - Colby Geary
- Biomedical Engineering, Pennsylvania State University, University Park, PA, USA
| | - Julianna C Simon
- Biomedical Engineering, Pennsylvania State University, University Park, PA, USA; Graduate Program in Acoustics, Pennsylvania State University, University Park, PA, USA
| | - Meghan E Vidt
- Biomedical Engineering, Pennsylvania State University, University Park, PA, USA; Physical Medicine & Rehabilitation, Penn State College of Medicine, Hershey, PA, USA.
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15
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Huegel J, Nuss CA, Chan PYW, Cheema AN, Kuntz AF, Soslowsky LJ. Chronic Nicotine Exposure Minimally Affects Rat Supraspinatus Tendon Properties and Bone Microstructure. Ann Biomed Eng 2021; 49:1333-1341. [PMID: 33145676 PMCID: PMC8062272 DOI: 10.1007/s10439-020-02667-x] [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: 05/20/2020] [Accepted: 10/20/2020] [Indexed: 11/26/2022]
Abstract
Cigarette smoking is the largest cause of preventable deaths, and a known risk factor for musculoskeletal issues including rotator cuff tendon tears. Tendon degeneration is believed to be due in part to changes in tendon cell health and collagen structure. Several studies have demonstrated that exposure to nicotine negatively impacts tendon healing, but surprisingly, nicotine exposure was shown to increase rat supraspinatus tendon stiffness. In order to address this seeming contradiction, the objective of this study was to comprehensively investigate the effects of long-term (18 weeks) exposure of nicotine on tendon-to-bone microstructural properties in a rat model. We hypothesized that long term subcutaneous nicotine delivery would lead to diminished tendon mechanical properties, decreased bone microstructure in the humeral head, and altered tendon cell morphology compared to age-matched control rats receiving saline. Results demonstrated a small decrease in tendon size and stiffness, with decreased cell density in the tendon midsubstance. However, no differences were found in the enthesis fibrocartilage or in the underlying subchondral or trabecular bone. In conclusion, our study revealed limited effects of nicotine on the homeostatic condition of the supraspinatus tendon, enthesis, and underlying bone. Future studies are needed to ascertain effects of other components of tobacco products.
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Affiliation(s)
- Julianne Huegel
- McKay Orthopaedic Research Laboratory, University of Pennsylvania, 3450 Hamilton Walk, 371 Stemmler Hall, Philadelphia, PA, 19104-6081, USA
| | - Courtney A Nuss
- McKay Orthopaedic Research Laboratory, University of Pennsylvania, 3450 Hamilton Walk, 371 Stemmler Hall, Philadelphia, PA, 19104-6081, USA
| | - Peter Y W Chan
- McKay Orthopaedic Research Laboratory, University of Pennsylvania, 3450 Hamilton Walk, 371 Stemmler Hall, Philadelphia, PA, 19104-6081, USA
| | - Adnan N Cheema
- McKay Orthopaedic Research Laboratory, University of Pennsylvania, 3450 Hamilton Walk, 371 Stemmler Hall, Philadelphia, PA, 19104-6081, USA
| | - Andrew F Kuntz
- McKay Orthopaedic Research Laboratory, University of Pennsylvania, 3450 Hamilton Walk, 371 Stemmler Hall, Philadelphia, PA, 19104-6081, USA
| | - Louis J Soslowsky
- McKay Orthopaedic Research Laboratory, University of Pennsylvania, 3450 Hamilton Walk, 371 Stemmler Hall, Philadelphia, PA, 19104-6081, USA.
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16
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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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17
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Healthy women confined to 60 days of bed rest showed no change in Achilles tendon dimensions but reduced calcaneal bone density. Ann Phys Rehabil Med 2020; 64:101412. [PMID: 32619632 DOI: 10.1016/j.rehab.2020.05.014] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2019] [Revised: 05/19/2020] [Accepted: 05/24/2020] [Indexed: 11/22/2022]
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18
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Bonilla KA, Pardes AM, Freedman BR, Soslowsky LJ. Supraspinatus Tendons Have Different Mechanical Properties Across Sex. J Biomech Eng 2020; 141:2701591. [PMID: 30167668 DOI: 10.1115/1.4041321] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2017] [Indexed: 12/31/2022]
Abstract
Sex differences in the mechanical properties of different musculoskeletal tissues and their impact on tendon function and disease are becoming increasingly recognized. Tendon mechanical properties are influenced by the presence or absence of sex hormones and these effects appear to be tendon- or ligament-specific. The objective of this study was to determine how sex and hormone differences in rats affect supraspinatus tendon and muscle properties. We hypothesized that male supraspinatus tendons would have increased cross-sectional area but no differences in tendon material properties or muscle composition when compared to supraspinatus tendons from female or ovariectomized (OVX) female rats. Uninjured supraspinatus tendons and muscles from male, female, and OVX female rats were collected and mechanical and histological properties were determined. Our analysis demonstrated decreased dynamic modulus and increased hysteresis and cross-sectional area in male tendons. We found that male tendons exhibited decreased dynamic modulus (during low strain frequency sweep and high strain fatigue loading), increased hysteresis, and increased cross-sectional area compared to female and OVX female tendons. Despite robust mechanical differences, tendon cell density and shape, and muscle composition remained unchanged between groups. Interestingly, these differences were unique compared to previously reported sex differences in rat Achilles tendons, which further supports the concept that the effect of sex on tendon varies anatomically. These differences may partially provide a mechanistic explanation for the increased rate of acute supraspinatus tendon ruptures seen in young males.
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Affiliation(s)
- K A Bonilla
- McKay Orthopaedic Laboratory, University of Pennsylvania, Philadelphia, PA 19104
| | - A M Pardes
- McKay Orthopaedic Laboratory, University of Pennsylvania, Philadelphia, PA 19104
| | - B R Freedman
- McKay Orthopaedic Laboratory, University of Pennsylvania, Philadelphia, PA 19104.,John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, MA 02138.,Wyss Institute for Biologically Inspired Engineering, Harvard University, Cambridge, MA 02115
| | - L J Soslowsky
- McKay Orthopaedic Laboratory, University of Pennsylvania, Stemmler Hall, 3450 Hamilton Walk, Philadelphia, PA 19104 e-mail:
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19
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Ryan CNM, Zeugolis DI. Engineering the Tenogenic Niche In Vitro with Microenvironmental Tools. ADVANCED THERAPEUTICS 2019. [DOI: 10.1002/adtp.201900072] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Affiliation(s)
- Christina N. M. Ryan
- Regenerative, Modular and Developmental Engineering LaboratoryBiomedical Sciences BuildingNational University of Ireland Galway Galway H91 W2TY Ireland
- Science Foundation Ireland, Centre for Research in Medical DevicesBiomedical Sciences BuildingNational University of Ireland Galway Galway H91 W2TY Ireland
| | - Dimitrios I. Zeugolis
- Regenerative, Modular and Developmental Engineering LaboratoryBiomedical Sciences BuildingNational University of Ireland Galway Galway H91 W2TY Ireland
- Science Foundation Ireland, Centre for Research in Medical DevicesBiomedical Sciences BuildingNational University of Ireland Galway Galway H91 W2TY Ireland
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20
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Onset of neonatal locomotor behavior and the mechanical development of Achilles and tail tendons. J Biomech 2019; 96:109354. [PMID: 31630773 DOI: 10.1016/j.jbiomech.2019.109354] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2019] [Revised: 08/21/2019] [Accepted: 09/18/2019] [Indexed: 12/27/2022]
Abstract
Tendon tissue engineering approaches are challenged by a limited understanding of the role mechanical loading plays in normal tendon development. We propose that the increased loading that developing postnatal tendons experience with the onset of locomotor behavior impacts tendon formation. The objective of this study was to assess the onset of spontaneous weight-bearing locomotion in postnatal day (P) 1, 5, and 10 rats, and characterize the relationship between locomotion and the mechanical development of weight-bearing and non-weight-bearing tendons. Movement was video recorded and scored to determine non-weight-bearing, partial weight-bearing, and full weight-bearing locomotor behavior at P1, P5, and P10. Achilles tendons, as weight-bearing tendons, and tail tendons, as non-weight-bearing tendons, were mechanically evaluated. We observed a significant increase in locomotor behavior in P10 rats, compared to P1 and P5. We also found corresponding significant differences in the maximum force, stiffness, displacement at maximum force, and cross-sectional area in Achilles tendons, as a function of postnatal age. However, the maximum stress, strain at maximum stress, and elastic modulus remained constant. Tail tendons of P10 rats had significantly higher maximum force, maximum stress, elastic modulus, and stiffness compared to P5. Our results suggest that the onset of locomotor behavior may be providing the mechanical cues regulating postnatal tendon growth, and their mechanical development may proceed differently in weight-bearing and non-weight-bearing tendons. Further analysis of how this loading affects developing tendons in vivo may inform future engineering approaches aiming to apply such mechanical cues to regulate engineered tendon formation in vitro.
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21
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Javidi M, McGowan CP, Schiele NR, Lin DC. Tendons from kangaroo rats are exceptionally strong and tough. Sci Rep 2019; 9:8196. [PMID: 31160640 PMCID: PMC6546749 DOI: 10.1038/s41598-019-44671-9] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2018] [Accepted: 05/17/2019] [Indexed: 11/14/2022] Open
Abstract
Tendons must be able to withstand the forces generated by muscles and not fail. Accordingly, a previous comparative analysis across species has shown that tendon strength (i.e., failure stress) increases for larger species. In addition, the elastic modulus increases proportionally to the strength, demonstrating that the two properties co-vary. However, some species may need specially adapted tendons to support high performance motor activities, such as sprinting and jumping. Our objective was to determine if the tendons of kangaroo rats (k-rat), small bipedal animals that can jump as high as ten times their hip height, are an exception to the linear relationship between elastic modulus and strength. We measured and compared the material properties of tendons from k-rat ankle extensor muscles to those of similarly sized white rats. The elastic moduli of k-rat and rat tendons were not different, but k-rat tendon failure stresses were much larger than the rat values (nearly 2 times larger), as were toughness (over 2.5 times larger) and ultimate strain (over 1.5 times longer). These results support the hypothesis that the tendons from k-rats are specially adapted for high motor performance, and k-rat tendon could be a novel model for improving tissue engineered tendon replacements.
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Affiliation(s)
- Mehrdad Javidi
- Voiland School of Chemical Engineering and Bioengineering, Washington State University, PO Box 646515, Pullman, WA, 99164, USA
| | - Craig P McGowan
- Department of Biological Sciences, University of Idaho, 875 Perimeter Drive, MS 3051, Moscow, ID, 83844, USA.,WWAMI Medical Education Program, University of Idaho, 875 Perimeter Drive, MS 4207, Moscow, ID, 83844, USA.,Washington Center for Muscle Biology, Washington State University, PO Box 646515, Pullman, WA, 99164, USA
| | - Nathan R Schiele
- Department of Biological Engineering, University of Idaho, 875 Perimeter Dr. MS 0904, Moscow, ID, 83844, USA
| | - David C Lin
- Voiland School of Chemical Engineering and Bioengineering, Washington State University, PO Box 646515, Pullman, WA, 99164, USA. .,Washington Center for Muscle Biology, Washington State University, PO Box 646515, Pullman, WA, 99164, USA. .,Department of Integrative Physiology and Neuroscience, Washington State University, PO Box 647620, Pullman, WA, 99164, USA.
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22
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Freedman BR, Mooney DJ. Biomaterials to Mimic and Heal Connective Tissues. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2019; 31:e1806695. [PMID: 30908806 PMCID: PMC6504615 DOI: 10.1002/adma.201806695] [Citation(s) in RCA: 107] [Impact Index Per Article: 21.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/15/2018] [Revised: 01/27/2019] [Indexed: 05/11/2023]
Abstract
Connective tissue is one of the four major types of animal tissue and plays essential roles throughout the human body. Genetic factors, aging, and trauma all contribute to connective tissue dysfunction and motivate the need for strategies to promote healing and regeneration. The goal here is to link a fundamental understanding of connective tissues and their multiscale properties to better inform the design and translation of novel biomaterials to promote their regeneration. Major clinical problems in adipose tissue, cartilage, dermis, and tendon are discussed that inspire the need to replace native connective tissue with biomaterials. Then, multiscale structure-function relationships in native soft connective tissues that may be used to guide material design are detailed. Several biomaterials strategies to improve healing of these tissues that incorporate biologics and are biologic-free are reviewed. Finally, important guidance documents and standards (ASTM, FDA, and EMA) that are important to consider for translating new biomaterials into clinical practice are highligted.
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Affiliation(s)
- Benjamin R Freedman
- John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, MA, 02138, USA
- Wyss Institute for Biologically Inspired Engineering, Harvard University, Boston, MA, 02115, USA
| | - David J Mooney
- John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, MA, 02138, USA
- Wyss Institute for Biologically Inspired Engineering, Harvard University, Boston, MA, 02115, USA
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23
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Cheema AN, Newton JB, Boorman-Padgett JF, Weiss SN, Nuss CA, Gittings DJ, Farber DC, Soslowsky LJ. Nicotine impairs intra-substance tendon healing after full thickness injury in a rat model. J Orthop Res 2019; 37:94-103. [PMID: 30345583 PMCID: PMC6411046 DOI: 10.1002/jor.24167] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/27/2018] [Accepted: 10/11/2018] [Indexed: 02/04/2023]
Abstract
Nicotine is harmful to many bodily systems; however, the effects of nicotine on intra-substance tendon healing remain largely unexplored. The purpose of this study was to examine the functional, structural, and biomechanical effects of nicotine on the healing of Achilles tendons in rats after an acute full-thickness injury. Sixty Sprague-Dawley rats were enrolled in this study. Half were exposed to 0.9% saline and half to 61 ng/mL of nicotine for 3 months via subcutaneous osmotic pumps. At 3 months, all rats underwent blunt full thickness transection of the left Achilles tendon and were immobilized for one week in plantarflexion. In-vivo assays were conducted prior to injury, at 21 days, and at 42 days post-injury and included the following: Functional limb assessment, passive joint mechanics, and vascular evaluation. Rats were sacrificed at 21 and 42 days for biomechanical testing and histologic evaluation. Rats exposed to nicotine demonstrated decreased vascularity, greater alteration in gait mechanics, and increased passive ROM of the ankle joint. Biomechanically, the nicotine tendons failed at lower maximum loads, were less stiff, had smaller cross-sectional areas and had altered viscoelastic properties. Histologically, nicotine tendons demonstrated decreased vessel density at the injury site. This study demonstrates that nicotine leads to worse functional outcomes and biomechanical properties in tendons. The decreased vascularity in the nicotine group may suggest an underlying mechanism for inferior tendon healing. Patients should be counseled that using nicotine products increase their risk of poor tendon healing and may predispose them to tendon re-rupture. © 2018 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res.
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Affiliation(s)
| | | | | | | | | | | | | | - Louis J. Soslowsky
- Corresponding Author: Louis J. Soslowsky, McKay Orthopaedic Research Laboratory, University of Pennsylvania, 3450 Hamilton Walk, 110 Stemmler Hall, Philadelphia, PA 19104-6081, United States of America, Phone: 215-898- 8653, Fax: 215-573- 2133,
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24
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Szczesny SE, Aeppli C, David A, Mauck RL. Fatigue loading of tendon results in collagen kinking and denaturation but does not change local tissue mechanics. J Biomech 2018. [PMID: 29519673 DOI: 10.1016/j.jbiomech.2018.02.014] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Fatigue loading is a primary cause of tendon degeneration, which is characterized by the disruption of collagen fibers and the appearance of abnormal (e.g., cartilaginous, fatty, calcified) tissue deposits. The formation of such abnormal deposits, which further weakens the tissue, suggests that resident tendon cells acquire an aberrant phenotype in response to fatigue damage and the resulting altered mechanical microenvironment. While fatigue loading produces clear changes in collagen organization and molecular denaturation, no data exist regarding the effect of fatigue on the local tissue mechanical properties. Therefore, the objective of this study was to identify changes in the local tissue stiffness of tendons after fatigue loading. We hypothesized that fatigue damage would reduce local tissue stiffness, particularly in areas with significant structural damage (e.g., collagen denaturation). We tested this hypothesis by identifying regions of local fatigue damage (i.e., collagen fiber kinking and molecular denaturation) via histologic imaging and by measuring the local tissue modulus within these regions via atomic force microscopy (AFM). Counter to our initial hypothesis, we found no change in the local tissue modulus as a consequence of fatigue loading, despite widespread fiber kinking and collagen denaturation. These data suggest that immediate changes in topography and tissue structure - but not local tissue mechanics - initiate the early changes in tendon cell phenotype as a consequence of fatigue loading that ultimately culminate in tendon degeneration.
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Affiliation(s)
- Spencer E Szczesny
- Department of Orthopaedic Surgery, University of Pennsylvania, 110 Stemmler Hall, 36th Street & Hamilton Walk, Philadelphia, PA 19104, United States; Department of Biomedical Engineering, Department of Orthopaedics and Rehabilitation, Pennsylvania State University, 205 Hallowell Building, University Park, PA 16802, United States.
| | - Céline Aeppli
- Eidgenössische Technische Hochschule, Rämistrasse 101, 8092 Zürich, Switzerland
| | - Alexander David
- Department of Bioengineering, 240 Skirkanich Hall, 210 South 33rd Street, University of Pennsylvania, Philadelphia, PA 19104, United States
| | - Robert L Mauck
- Department of Orthopaedic Surgery, University of Pennsylvania, 110 Stemmler Hall, 36th Street & Hamilton Walk, Philadelphia, PA 19104, United States; Department of Bioengineering, 240 Skirkanich Hall, 210 South 33rd Street, University of Pennsylvania, Philadelphia, PA 19104, United States; Translational Musculoskeletal Research Center, Corporal Michael J. Crescenz Veterans Affairs Medical Center, 3900 Woodland Avenue, Philadelphia, PA 19104, United States
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25
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Ackerman JE, Bah I, Jonason JH, Buckley MR, Loiselle AE. Aging does not alter tendon mechanical properties during homeostasis, but does impair flexor tendon healing. J Orthop Res 2017; 35:2716-2724. [PMID: 28419543 PMCID: PMC5645212 DOI: 10.1002/jor.23580] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/23/2016] [Accepted: 04/12/2017] [Indexed: 02/04/2023]
Abstract
Aging is an important factor in disrupted homeostasis of many tissues. While an increased incidence of tendinopathy and tendon rupture are observed with aging, it is unclear whether this is due to progressive changes in tendon cell function and mechanics over time, or an impaired repair reaction from aged tendons in response to insult or injury. In the present study, we examined changes in the mechanical properties of Flexor Digitorum Longus (FDL), Flexor Carpi Ulnaris (FCU), and tail fascicles in both male and female C57Bl/6 mice between 3 and 27 months of age to better understand the effects of sex and age on tendon homeostasis. No change in max load at failure was observed in any group over the course of aging, although there were significant decreases in toe and linear stiffness in female mice from 3 to 15 months, and 3 to 27 months. No changes in cell proliferation were observed with aging, although an observable decrease in cellularity occurred in 31-month old tendons. Given that aging did not dramatically alter tendon mechanical homeostasis we hypothesized that a disruption in tendon homeostasis, via acute injury would result in an impaired healing response. Significant decreases in max load, stiffness, and yield load were observed in repairs of 22-month old mice, relative to 4-month old mice. No changes in cell proliferation were observed between young and aged, however, a dramatic loss of bridging collagen extracellular matrix was observed in aged repairs suggest that matrix production, but not cell proliferation leads to impaired tendon healing with aging. Results © 2017 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 35:2716-2724, 2017.
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Affiliation(s)
- Jessica E. Ackerman
- Center for Musculoskeletal Research, Department of Orthopaedics & Rehabilitation, University of Rochester Medical Center, Rochester, NY 14642
| | - Ibrahima Bah
- Center for Musculoskeletal Research, Department of Orthopaedics & Rehabilitation, University of Rochester Medical Center, Rochester, NY 14642,Department of Biomedical Engineering, University of Rochester, Rochester, NY 14642
| | - Jennifer H. Jonason
- Center for Musculoskeletal Research, Department of Orthopaedics & Rehabilitation, University of Rochester Medical Center, Rochester, NY 14642
| | - Mark R. Buckley
- Center for Musculoskeletal Research, Department of Orthopaedics & Rehabilitation, University of Rochester Medical Center, Rochester, NY 14642,Department of Biomedical Engineering, University of Rochester, Rochester, NY 14642
| | - Alayna E. Loiselle
- Center for Musculoskeletal Research, Department of Orthopaedics & Rehabilitation, University of Rochester Medical Center, Rochester, NY 14642,Corresponding Author: Alayna E. Loiselle, PhD, Center for Musculoskeletal Research, University of Rochester Medical Center, 601 Elmwood Ave, Box 665, Rochester, NY, 14642, Phone: 585-275-7239, Fax: 585-276-2177,
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26
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Bordvik DH, Haslerud S, Naterstad IF, Lopes-Martins RAB, Leal Junior ECP, Bjordal JM, Joensen J. Penetration Time Profiles for Two Class 3B Lasers inIn SituHuman Achilles at Rest and Stretched. Photomed Laser Surg 2017; 35:546-554. [DOI: 10.1089/pho.2016.4257] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Affiliation(s)
- Daniel Huseby Bordvik
- NorPhyPain Research Group, Faculty of Health and Social Sciences, Centre for Evidence Based Practice, Bergen University College, Bergen, Norway
- Physiotherapy Research Group, Department of Global Public Health and Primary Care, University of Bergen, Bergen, Norway
- Haugesund Rheumatological Hospital, Rehabilitation West A/S, Haugesund, Norway
| | - Sturla Haslerud
- NorPhyPain Research Group, Faculty of Health and Social Sciences, Centre for Evidence Based Practice, Bergen University College, Bergen, Norway
- Physiotherapy Research Group, Department of Global Public Health and Primary Care, University of Bergen, Bergen, Norway
| | - Ingvill Fjell Naterstad
- NorPhyPain Research Group, Faculty of Health and Social Sciences, Centre for Evidence Based Practice, Bergen University College, Bergen, Norway
- Physiotherapy Research Group, Department of Global Public Health and Primary Care, University of Bergen, Bergen, Norway
| | - Rodrigo Alvaro Brandão Lopes-Martins
- Nucleous of Technological Research—NPT, Post-Graduate Program in Biomedical Engineering, University of Mogi das Cruzes (UMC), Mogi das Cruzes, São Paulo, Brazil
| | | | - Jan Magnus Bjordal
- NorPhyPain Research Group, Faculty of Health and Social Sciences, Centre for Evidence Based Practice, Bergen University College, Bergen, Norway
- Physiotherapy Research Group, Department of Global Public Health and Primary Care, University of Bergen, Bergen, Norway
- Department of Occupational Therapy, Physiotherapy and Radiography, Bergen University College, Bergen, Norway
| | - Jon Joensen
- NorPhyPain Research Group, Faculty of Health and Social Sciences, Centre for Evidence Based Practice, Bergen University College, Bergen, Norway
- Physiotherapy Research Group, Department of Global Public Health and Primary Care, University of Bergen, Bergen, Norway
- Department of Occupational Therapy, Physiotherapy and Radiography, Bergen University College, Bergen, Norway
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27
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Sarver DC, Kharaz YA, Sugg KB, Gumucio JP, Comerford E, Mendias CL. Sex differences in tendon structure and function. J Orthop Res 2017; 35:2117-2126. [PMID: 28071813 PMCID: PMC5503813 DOI: 10.1002/jor.23516] [Citation(s) in RCA: 46] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/14/2016] [Accepted: 01/06/2017] [Indexed: 02/04/2023]
Abstract
Tendons play a critical role in the transmission of forces between muscles and bones, and chronic tendon injuries and diseases are among the leading causes of musculoskeletal disability. Little is known about sex-based differences in tendon structure and function. Our objective was to evaluate the mechanical properties, biochemical composition, transcriptome, and cellular activity of plantarflexor tendons from 4 month old male and female C57BL/6 mice using in vitro biomechanics, mass spectrometry-based proteomics, genome-wide expression profiling, and cell culture techniques. While the Achilles tendons of male mice were approximately 6% larger than female mice (p < 0.05), the cell density of female mice was around 19% greater than males (p < 0.05). No significant differences in mechanical properties (p > 0.05) of plantaris tendons were observed. Mass spectrometry proteomics analysis revealed no significant difference between sexes in the abundance of major extracellular matrix (ECM) proteins such as collagen types I (p = 0.30) and III (p = 0.68), but female mice had approximately twofold elevations (p < 0.05) in less abundant ECM proteins such as fibronectin, periostin, and tenascin C. The transcriptome of male and female tendons differed by only 1%. In vitro, neither the sex of the serum that fibroblasts were cultured in, nor the sex of the ECM in which they were embedded, had profound effects on the expression of collagen and cell proliferation genes. Our results indicate that while male mice expectedly had larger tendons, male and female tendons have very similar mechanical properties and biochemical composition, with small increases in some ECM proteins and proteoglycans evident in female tendons. © 2017 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 35:2117-2126, 2017.
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Affiliation(s)
- Dylan C Sarver
- Department of Orthopaedic Surgery, Section of Plastic Surgery, University of Michigan Medical School, Ann Arbor, MI, USA
| | - Yalda Ashraf Kharaz
- Department of Musculoskeletal Biology, Institute of Ageing and Chronic Disease, University of Liverpool, Liverpool, UK
| | - Kristoffer B Sugg
- Department of Orthopaedic Surgery, Section of Plastic Surgery, University of Michigan Medical School, Ann Arbor, MI, USA,Department of Molecular & Integrative Physiology, Section of Plastic Surgery, University of Michigan Medical School, Ann Arbor, MI, USA,Department of Surgery, Section of Plastic Surgery, University of Michigan Medical School, Ann Arbor, MI, USA
| | - Jonathan P Gumucio
- Department of Orthopaedic Surgery, Section of Plastic Surgery, University of Michigan Medical School, Ann Arbor, MI, USA,Department of Molecular & Integrative Physiology, Section of Plastic Surgery, University of Michigan Medical School, Ann Arbor, MI, USA
| | - Eithne Comerford
- Department of Musculoskeletal Biology, Institute of Ageing and Chronic Disease, University of Liverpool, Liverpool, UK
| | - Christopher L Mendias
- Department of Orthopaedic Surgery, Section of Plastic Surgery, University of Michigan Medical School, Ann Arbor, MI, USA,Department of Molecular & Integrative Physiology, Section of Plastic Surgery, University of Michigan Medical School, Ann Arbor, MI, USA,Corresponding Author: Christopher L Mendias, PhD, Department of Orthopaedic Surgery, University of Michigan Medical School, 109 Zina Pitcher Place, BSRB 2017, Ann Arbor, MI 48109-2200, 734-764-3250, 734-647-0003 fax,
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28
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Temporal Healing of Achilles Tendons After Injury in Rodents Depends on Surgical Treatment and Activity. J Am Acad Orthop Surg 2017; 25:635-647. [PMID: 28837456 PMCID: PMC5603242 DOI: 10.5435/jaaos-d-16-00620] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
INTRODUCTION Achilles tendon ruptures affect 15 of 100,000 women and 55 of 100,000 men each year. Controversy continues to exist regarding optimal treatment and rehabilitation protocols. The objective of this study was to investigate the temporal effects of surgical repair and immobilization or activity on Achilles tendon healing and limb function after complete transection in rodents. METHODS Injured tendons were repaired (n = 64) or left nonrepaired (n = 64). The animals in both cohorts were further randomized into groups immobilized in plantar flexion for 1, 3, or 6 weeks that later resumed cage and treadmill activity for 5, 3, or 0 weeks, respectively (n = 36 for each regimen), which were euthanized at 6 weeks after injury, or into groups immobilized for 1 week and then euthanized (n = 20). RESULTS At 6 weeks after injury, the groups that had 1 week of immobilization and 5 weeks of activity had increased range of motion and decreased ankle joint toe stiffness compared with the groups that had 3 weeks of immobilization and 3 weeks of activity. The groups with 6 weeks of immobilization and no activity period had decreased tendon cross-sectional area but increased tendon echogenicity and collagen alignment. Surgical treatment dramatically decreased fatigue cycles to failure in repaired tendons from groups with 1 week of immobilization and 5 weeks of activity. Normalized comparisons between 1-week and 6-week postinjury data demonstrated that changes in tendon healing properties (area, alignment, and echogenicity) were maximized by 1 week of immobilization and 5 weeks of activity, compared with 6 weeks of immobilization and no activity period. DISCUSSION This study builds on an earlier study of Achilles tendon fatigue mechanics and functional outcomes during early healing by examining the temporal effects of different immobilization and/or activity regimens after initial postinjury immobilization. CONCLUSION This study demonstrates how the temporal postinjury healing response of rodent Achilles tendons depends on both surgical treatment and the timing of immobilization/activity timing. The different pattern of healing and qualities of repaired and nonrepaired tendons suggest that two very different healing processes may occur, depending on the chosen immobilization/activity regimen.
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29
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Pardes AM, Beach ZM, Raja H, Rodriguez AB, Freedman BR, Soslowsky LJ. Aging leads to inferior Achilles tendon mechanics and altered ankle function in rodents. J Biomech 2017; 60:30-38. [PMID: 28683928 DOI: 10.1016/j.jbiomech.2017.06.008] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2017] [Revised: 06/03/2017] [Accepted: 06/06/2017] [Indexed: 12/29/2022]
Abstract
Spontaneous rupture of the Achilles tendon is increasingly common in the middle aged population. However, the cause for the particularly high incidence of injury in this age group is not well understood. Therefore, the objective of this study was to identify age-specific differences in the Achilles tendon-muscle complex using an animal model. Functional measures were performed in vivo and tissues were harvested following euthanasia for mechanical, structural, and histological analysis from young, middle aged, and old rats. Numerous alterations in tendon properties were detected across age groups, including inferior material properties (maximum stress, modulus) with increasing age. Differences in function were also observed, as older animals exhibited increased ankle joint passive stiffness and decreased propulsion force during locomotion. Macroscale differences in tendon organization were not observed, although cell density and nuclear shape did vary between age groups. Muscle fiber size and type distribution were not notably affected by age, indicating that other factors may be more responsible for age-specific Achilles tendon rupture rates. This study improves our understanding of the role of aging in Achilles tendon biomechanics and ankle function, and helps provide a potential explanation for the disparate incidence of Achilles tendon ruptures in varying age groups.
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Affiliation(s)
- A M Pardes
- McKay Orthopaedic Laboratory, University of Pennsylvania, Philadelphia, PA, USA
| | - Z M Beach
- McKay Orthopaedic Laboratory, University of Pennsylvania, Philadelphia, PA, USA
| | - H Raja
- McKay Orthopaedic Laboratory, University of Pennsylvania, Philadelphia, PA, USA
| | - A B Rodriguez
- McKay Orthopaedic Laboratory, University of Pennsylvania, Philadelphia, PA, USA
| | - B R Freedman
- McKay Orthopaedic Laboratory, University of Pennsylvania, Philadelphia, PA, USA
| | - L J Soslowsky
- McKay Orthopaedic Laboratory, University of Pennsylvania, Philadelphia, PA, USA.
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30
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Freedman BR, Fryhofer GW, Salka NS, Raja HA, Hillin CD, Nuss CA, Farber DC, Soslowsky LJ. Mechanical, histological, and functional properties remain inferior in conservatively treated Achilles tendons in rodents: Long term evaluation. J Biomech 2017; 56:55-60. [PMID: 28366437 PMCID: PMC5393933 DOI: 10.1016/j.jbiomech.2017.02.030] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2016] [Revised: 02/22/2017] [Accepted: 02/27/2017] [Indexed: 12/31/2022]
Abstract
Conservative treatment (non-operative) of Achilles tendon ruptures is suggested to produce equivalent capacity for return to function; however, long term results and the role of return to activity (RTA) for this treatment paradigm remain unclear. Therefore, the objective of this study was to evaluate the long term response of conservatively treated Achilles tendons in rodents with varied RTA. Sprague Dawley rats (n=32) received unilateral blunt transection of the Achilles tendon followed by randomization into groups that returned to activity after 1-week (RTA1) or 3-weeks (RTA3) of limb casting in plantarflexion, before being euthanized at 16-weeks post-injury. Uninjured age-matched control animals were used as a control group (n=10). Limb function, passive joint mechanics, tendon properties (mechanical, histological), and muscle properties (histological, immunohistochemical) were evaluated. Results showed that although hindlimb ground reaction forces and range of motion returned to baseline levels by 16-weeks post-injury regardless of RTA, ankle joint stiffness remained altered. RTA1 and RTA3 groups both exhibited no differences in fatigue properties; however, the secant modulus, hysteresis, and laxity were inferior compared to uninjured age-matched control tendons. Despite these changes, tendons 16-weeks post-injury achieved secant stiffness levels of uninjured tendons. RTA1 and RTA3 groups had no differences in histological properties, but had higher cell numbers compared to control tendons. No changes in gastrocnemius fiber size or type in the superficial or deep regions were detected, except for type 2x fiber fraction. Together, this work highlights RTA-dependent deficits in limb function and tissue-level properties in long-term Achilles tendon and muscle healing.
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Affiliation(s)
| | - George W Fryhofer
- McKay Orthopedic Research Laboratory, Philadelphia, PA, United States
| | - Nabeel S Salka
- McKay Orthopedic Research Laboratory, Philadelphia, PA, United States
| | - Harina A Raja
- McKay Orthopedic Research Laboratory, Philadelphia, PA, United States
| | - Cody D Hillin
- McKay Orthopedic Research Laboratory, Philadelphia, PA, United States
| | - Courtney A Nuss
- McKay Orthopedic Research Laboratory, Philadelphia, PA, United States
| | - Daniel C Farber
- McKay Orthopedic Research Laboratory, Philadelphia, PA, United States
| | - Louis J Soslowsky
- McKay Orthopedic Research Laboratory, Philadelphia, PA, United States.
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31
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Fryhofer GW, Freedman BR, Hillin CD, Salka NS, Pardes AM, Weiss SN, Farber DC, Soslowsky LJ. Postinjury biomechanics of Achilles tendon vary by sex and hormone status. J Appl Physiol (1985) 2016; 121:1106-1114. [PMID: 27633741 DOI: 10.1152/japplphysiol.00620.2016] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2016] [Accepted: 09/12/2016] [Indexed: 12/11/2022] Open
Abstract
Achilles tendon ruptures are common injuries. Sex differences are present in mechanical properties of uninjured Achilles tendon, but it remains unknown if these differences extend to tendon healing. We hypothesized that ovariectomized females (OVX) and males would exhibit inferior postinjury tendon properties compared with females. Male, female, and OVX Sprague-Dawley rats (n = 32/group) underwent acclimation and treadmill training before blunt transection of the Achilles tendon midsubstance. Injured hindlimbs were immobilized for 1 wk, followed by gradual return to activity and assessment of active and passive hindlimb function. Animals were euthanized at 3 or 6 wk postinjury to assess tendon structure, mechanics, and composition. Passive ankle stiffness and range of motion were superior in females at 3 wk; however, by 6 wk, passive and active function were similar in males and females but remained inferior in OVX. At 6 wk, female tendons had greater normalized secant modulus, viscoelastic behavior, and laxity compared with males. Normalized secant modulus, cross-sectional area and tendon glycosaminoglycan composition were inferior in OVX compared with females at 6 wk. Total fatigue cycles until tendon failure were similar among groups. Postinjury muscle fiber size was better preserved in females compared with males, and females had greater collagen III at the tendon injury site compared with males at 6 wk. Despite male and female Achilles tendons withstanding similar durations of fatigue loading, early passive hindlimb function and tendon mechanical properties, including secant modulus, suggest superior healing in females. Ovarian hormone loss was associated with inferior Achilles tendon healing.
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Affiliation(s)
- George W Fryhofer
- McKay Orthopaedic Laboratory, Department of Orthopaedic Surgery, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Benjamin R Freedman
- McKay Orthopaedic Laboratory, Department of Orthopaedic Surgery, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Cody D Hillin
- McKay Orthopaedic Laboratory, Department of Orthopaedic Surgery, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Nabeel S Salka
- McKay Orthopaedic Laboratory, Department of Orthopaedic Surgery, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Adam M Pardes
- McKay Orthopaedic Laboratory, Department of Orthopaedic Surgery, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Stephanie N Weiss
- McKay Orthopaedic Laboratory, Department of Orthopaedic Surgery, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Daniel C Farber
- McKay Orthopaedic Laboratory, Department of Orthopaedic Surgery, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Louis J Soslowsky
- McKay Orthopaedic Laboratory, Department of Orthopaedic Surgery, University of Pennsylvania, Philadelphia, Pennsylvania
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