Tendinopathy

{{Short description|Inflammation of the tendon}} {{cs1 config|name-list-style=vanc}} {{distinguish|Tenonitis|Tenosynovitis}} {{Infobox medical condition (new) | name = Tendinopathy | synonyms = tendinitis, tendinosis<ref name=AFP2005>{{cite journal |vauthors=Wilson JJ, Best TM |title=Common overuse tendon problems: A review and recommendations for treatment |journal=American Family Physician |volume=72 |issue=5 |pages=811–8 |date=Sep 2005 |pmid=16156339 |url=http://www.aafp.org/afp/20050901/811.pdf |access-date=2007-04-02 |archive-date=2007-09-29 |archive-url=https://web.archive.org/web/20070929105600/http://www.aafp.org/afp/20050901/811.pdf }}</ref> | image = Achilles-tendon.jpg | image_size = 200px | caption = Achilles tendon (a commonly affected tendon) | pronounce = | field = Orthopedics | symptoms = Pain, swelling<ref name=NIH2017/> | complications = | onset = | duration = | types = | causes = Injury from vacation repetitive activities, overuse<ref name=NIH2017/> | risks = | diagnosis = Based on symptoms, examination, medical imaging<ref name=NIH2017Diag/> | differential = | prevention = | treatment = Rest, NSAIDs, splinting, physiotherapy<ref name=NIH2017/> | medication = | prognosis = 80% better within 6 months for overuse tendinopathy<ref name=AFP2005/> | frequency = Common<ref name=AFP2005/><ref name=NIH2017/> | deaths = }}

'''Tendinopathy''' is a type of tendon disorder that results in pain, swelling, and impaired function.<ref name=NIH2017>{{cite web |title=Tendinitis |url=https://www.niams.nih.gov/health-topics/tendinitis/advanced |archive-url=https://web.archive.org/web/20171004212713/https://www.niams.nih.gov/health-topics/tendinitis/advanced |archive-date=October 4, 2017 |website=National Institute of Arthritis and Musculoskeletal and Skin Diseases |access-date=11 June 2024 |language=en |date=September 2021}}</ref> The pain is typically worse with movement.<ref name=NIH2017/> It most commonly occurs around the shoulder (rotator cuff tendinitis, biceps tendinitis), elbow (tennis elbow, golfer's elbow), wrist, hip, knee (jumper's knee, popliteus tendinopathy), or ankle (Achilles tendinitis).<ref name=AFP2005/><ref name=NIH2017/>

Causes may include an injury or repetitive activities.<ref name=NIH2017/> Less common causes include infection, arthritis, gout, thyroid disease, diabetes and the use of quinolone antibiotic medicines.<ref name="BMJ2002">{{cite web |date=1 June 2002 |title=Fluoroquinolones and risk of Achilles tendon disorders: case-control study |url= https://www.bmj.com/rapid-response/2011/10/29/tendinopathy-quinolones |access-date=21 September 2022 |website=British Medical Journal |language=en}}</ref><ref name="NIH2017Cau">{{cite web |date=12 April 2017 |title=Tendinitis |url=https://www.niams.nih.gov/health-topics/tendinitis/advanced#tab-causes |archive-url=https://web.archive.org/web/20171004212713/https://www.niams.nih.gov/health-topics/tendinitis/advanced#tab-causes |archive-date=October 4, 2017 |access-date=18 November 2018 |website=National Institute of Arthritis and Musculoskeletal and Skin Diseases |language=en}}</ref> Groups at risk include people who do manual labor, musicians, and athletes.<ref name=NIH2017/> Diagnosis is typically based on symptoms, examination, and occasionally medical imaging.<ref name=NIH2017Diag>{{cite web |title=Tendinitis |url=https://www.niams.nih.gov/health-topics/tendinitis/advanced#tab-diagnosis |archive-url=https://web.archive.org/web/20171004212713/https://www.niams.nih.gov/health-topics/tendinitis/advanced#tab-diagnosis |archive-date=October 4, 2017 |website=National Institute of Arthritis and Musculoskeletal and Skin Diseases |access-date=18 November 2018 |language=en |date=12 April 2017}}</ref> A few weeks following an injury little inflammation remains, with the underlying problem related to weak or disrupted tendon fibrils.<ref>{{cite journal |vauthors=Khan KM, Cook JL, Kannus P, Maffulli N, Bonar SF |title=Time to abandon the "tendinitis" myth: Painful, overuse tendon conditions have a non-inflammatory pathology |journal=BMJ |volume=324 |pages=626–7 |date=2002-03-16 |doi= 10.1136/bmj.324.7338.626|pmid=11895810 |pmc=1122566 |issue=7338 }}</ref>

Treatment may include rest, NSAIDs, splinting, and physiotherapy.<ref name=NIH2017/> Less commonly steroid injections or surgery may be done.<ref name=NIH2017/> About 80% of overuse tendinopathy patients recover completely within six months.<ref name=AFP2005/> Tendinopathy is relatively common.<ref name=NIH2017/> Older people are more commonly affected.<ref name=NIH2017/>

==Signs and symptoms== Symptoms include tenderness on palpation, swelling, and pain, often when exercising or with a specific movement.<ref>{{cite journal|title=Management of tendinopathy|journal=Am J Sports Med|pmid=19188560 | doi=10.1177/0363546508324283|volume=37|issue=9|date=Sep 2009|pages=1855–67|vauthors=Rees JD, Maffulli N, Cook J|s2cid=1810473}}</ref>

==Cause== Causes may include an injury or repetitive activities.<ref name=NIH2017/> Groups at risk include people who do manual labor, musicians, and athletes.<ref name=NIH2017/> Less common causes include infection, arthritis, gout, thyroid disease, and diabetes.<ref name=NIH2017Cau/> Obesity, or more specifically, adiposity or fatness, has also been linked to an increasing incidence of tendinopathy.<ref>{{cite journal |vauthors=Gaida JE, Ashe MC, Bass SL, Cook JL |date=2009 |title=Is adiposity an under-recognized risk factor for tendinopathy? A systematic review |journal=Arthritis Rheum |volume=61 |issue=6 |pages=840–9 |doi=10.1002/art.24518 |pmid=19479698 |doi-access=free}}</ref>

Quinolone antibiotics are associated with increased risk of tendinitis and tendon rupture.<ref name=FDA2016>FDA May 12, 2016 [https://www.fda.gov/drugs/drug-safety-and-availability/fda-drug-safety-communication-fda-advises-restricting-fluoroquinolone-antibiotic-use-certain FDA Drug Safety Communication: FDA advises restricting fluoroquinolone antibiotic use for certain uncomplicated infections; warns about disabling side effects that can occur]</ref> A 2013 review found the incidence of tendon injury among those taking fluoroquinolones to be between 0.08 and 0.2%.<ref name=QuinTendon2013>{{cite journal|last1=Stephenson|first1=AL|last2=Wu|first2=W|last3=Cortes|first3=D|last4=Rochon|first4=PA|title=Tendon Injury and Fluoroquinolone Use: A Systematic Review.|journal=Drug Safety|date=September 2013|volume=36|issue=9|pages=709–21|pmid=23888427|doi=10.1007/s40264-013-0089-8|s2cid=24948660}}</ref> Fluoroquinolones most frequently affect large load-bearing tendons in the lower limb, especially the Achilles tendon which ruptures in approximately 30 to 40% of cases.<ref>{{cite journal|last=Bolon|first=Brad|date=2017-01-01|title=Mini-Review: Toxic Tendinopathy|journal=Toxicologic Pathology|pages=834–837|doi=10.1177/0192623317711614|issn=1533-1601|pmid=28553748|volume=45|issue=7|doi-access=free}}</ref>

===Types=== Examples include:

* Achilles tendinitis * Calcific tendinitis * Patellar tendinitis (jumper's knee)

==Pathophysiology== As of 2016, the pathophysiology of tendinopathy is poorly understood. While inflammation appears to play a role, the relationships among changes to the structure of tissue, the function of tendons, and pain are not understood and there are several competing models, none of which have been fully validated or falsified.<ref name="Millar">{{cite journal|last1=Millar|first1=NL|last2=Murrell|first2=GA|last3=McInnes|first3=IB|title=Inflammatory mechanisms in tendinopathy - towards translation.|journal=Nature Reviews. Rheumatology|date=25 January 2017|volume=13|issue=2|pages=110–122|doi=10.1038/nrrheum.2016.213|pmid=28119539|s2cid=10794196}}</ref><ref>{{cite journal|last1=Cook|first1=JL|last2=Rio|first2=E|last3=Purdam|first3=CR|last4=Docking|first4=SI|title=Revisiting the continuum model of tendon pathology: what is its merit in clinical practice and research?|journal=British Journal of Sports Medicine|date=October 2016|volume=50|issue=19|pages=1187–91|pmid=27127294|pmc=5118437|doi=10.1136/bjsports-2015-095422}}</ref> Molecular mechanisms involved in inflammation includes release of inflammatory cytokines like IL-1β which reduces the expression of type I collagen mRNA in human tenocytes and causes extracellular matrix degradation in the tendon.<ref name="Millar"/> In a 2020 systematic review, it was noted that while various inflammatory markers were present in two thirds of the reviewed articles, the heterogenicity of data and lack of comparable studies meant no conclusion about a common pathophysiology from this systematic review.<ref>{{cite journal |vauthors=Jomaa G, etal |title=A systematic review of inflammatory cells and markers in human tendinopathy |journal=BMC Musculoskelet Disord |date=2020 |volume=21 |issue=1 |page=78 |doi=10.1186/s12891-020-3094-y|pmid=32028937 |pmc=7006114 |doi-access=free }}</ref>

There are multifactorial theories that could include: tensile overload, tenocyte related collagen synthesis disruption, load-induced ischemia, neural sprouting, thermal damage, and adaptive compressive responses. The intratendinous sliding motion of fascicles and shear force at interfaces of fascicles could be an important mechanical factor for the development of tendinopathy and predispose tendons to rupture.<ref>{{cite journal|vauthors=Sun YL, etal |title=Lubricin in Human Achilles Tendon: The Evidence of Intratendinous Sliding Motion and Shear Force in Achilles Tendon|journal=J Orthop Res|date=2015|volume=33|issue=6|pages=932–7|doi=10.1002/jor.22897|pmid=25864860|s2cid=20575820 |doi-access=free}}</ref>

The most commonly accepted cause for this condition is seen to be an overuse syndrome in combination with intrinsic and extrinsic factors leading to what may be seen as a progressive interference or the failing of the innate healing response. Tendinopathy involves cellular apoptosis, matrix disorganization and neovascularization.<ref>{{cite book|chapter-url=https://www.ncbi.nlm.nih.gov/books/NBK448174/|title=StatPearls|last1=Charnoff|first1=Jesse|last2=Naqvi|first2=Usker|date=2017|publisher=StatPearls Publishing|location=Treasure Island (FL)|pmid=28846334|chapter=Tendinosis (Tendinitis)}}</ref>

Classic characteristics of "tendinosis" include degenerative changes in the collagenous matrix, hypercellularity, hypervascularity, and a lack of inflammatory cells which has challenged the original misnomer "tendinitis".<ref name="pmid21144004">{{cite journal|vauthors=Fu SC, Rolf C, Cheuk YC, Lui PP, Chan KM | title=Deciphering the pathogenesis of tendinopathy: a three-stages process. | journal=Sports Med Arthrosc Rehabil Ther Technol | year= 2010 | volume= 2 | page= 30 | pmid=21144004 | doi=10.1186/1758-2555-2-30 | pmc=3006368 | doi-access=free }}</ref><ref name="pmid19591655">{{cite journal |vauthors=Abate M, Silbernagel KG, Siljeholm C, Di Iorio A, De Amicis D, Salini V, Werner S, Paganelli R |title=Pathogenesis of tendinopathies: inflammation or degeneration? |journal=Arthritis Research & Therapy |volume=11 |issue=3 |page=235 |year=2009 |pmid=19591655 |pmc=2714139 |doi=10.1186/ar2723 |doi-access=free }}</ref>

For chronic tennis elbow, histological findings include granulation tissue, microrupture, degenerative changes, and there is no traditional inflammation. As a consequence, "lateral elbow tendinopathy or tendinosis" is used instead of "lateral epicondylitis".<ref name="du ToitStieler2008">{{cite journal|last1=du Toit|first1=C|last2=Stieler|first2=M|last3=Saunders|first3=R|last4=Bisset|first4=L|last5=Vicenzino|first5=B|title=Diagnostic accuracy of power Doppler ultrasound in patients with chronic tennis elbow|journal=British Journal of Sports Medicine|volume=42|issue=11|year=2008|pages=572–576|issn=0306-3674|doi=10.1136/bjsm.2007.043901|pmid=18308874|hdl=10072/22142|s2cid=3274396|hdl-access=free}}</ref> Examination of pathologic tennis elbow tissue reveals noninflammatory tissue, so the term "angiofibroblastic tendinosis" is also used.<ref name="pmid1423702">{{cite journal |vauthors=Nirschl RP |title=Elbow tendinosis/tennis elbow |journal=Clin Sports Med |volume=11 |issue=4 |pages=851–70 | date=October 1992 |pmid=1423702 |doi= 10.1016/S0278-5919(20)30489-0}}</ref>

Cultures from tendinopathic tendons contain an increased production of type III collagen.<ref name="pmid10921640">{{cite journal|vauthors=Maffulli N, Ewen SW, Waterston SW, Reaper J, Barrass V | title=Tenocytes from ruptured and tendinopathic achilles tendons produce greater quantities of type III collagen than tenocytes from normal achilles tendons. An in vitro model of human tendon healing. | journal=Am J Sports Med | year= 2000 | volume= 28 | issue= 4 | pages= 499–505 | doi= 10.1177/03635465000280040901 | pmid=10921640 | s2cid=13511471 }}</ref><ref name="pmid25383170">{{cite journal|vauthors=Ho JO, Sawadkar P, Mudera V | title=A review on the use of cell therapy in the treatment of tendon disease and injuries. | journal=J Tissue Eng | year= 2014 | volume= 5 | article-number= 2041731414549678 | pmid=25383170 | doi=10.1177/2041731414549678 | pmc=4221986 }}</ref>

Longitudinal sonogram of the lateral elbow displays thickening and heterogeneity of the common extensor tendon that is consistent with tendinosis, as the ultrasound reveals calcifications, intrasubstance tears, and marked irregularity of the lateral epicondyle. Although the term "epicondylitis" is frequently used to describe this disorder, most histopathologic findings of studies have displayed no evidence of an acute, or a chronic inflammatory process. Histologic studies have demonstrated that this condition is the result of tendon degeneration, which causes normal tissue to be replaced by a disorganized arrangement of collagen. Therefore, the disorder is more appropriately referred to as "tendinosis" or "tendinopathy" rather than "tendinitis".<ref name="pmid16998100">{{cite journal |vauthors=McShane JM, Nazarian LN, Harwood MI |title=Sonographically guided percutaneous needle tenotomy for treatment of common extensor tendinosis in the elbow |journal=J Ultrasound Med |volume=25 |issue=10 |pages=1281–9 | date=October 2006 |pmid=16998100 |doi= 10.7863/jum.2006.25.10.1281|s2cid=22963436 |doi-access=free }}</ref>

Colour Doppler ultrasound reveals structural tendon changes, with vascularity and hypo-echoic areas that correspond to the areas of pain in the extensor origin.<ref name="ZeisigÖhberg2006">{{cite journal|last1=Zeisig|first1=Eva|last2=Öhberg|first2=Lars|last3=Alfredson|first3=Håkan|title=Sclerosing polidocanol injections in chronic painful tennis elbow-promising results in a pilot study|journal=Knee Surgery, Sports Traumatology, Arthroscopy|volume=14|issue=11|year=2006|pages=1218–1224|issn=0942-2056|doi=10.1007/s00167-006-0156-0|pmid=16960741|s2cid=23469092}}</ref>

Load-induced non-rupture tendinopathy in humans is associated with an increase in the ratio of collagen III:I proteins, a shift from large to small diameter collagen fibrils, buckling of the collagen fascicles in the tendon extracellular matrix, and buckling of the tenocyte cells and their nuclei.<ref name="pmid24571576">{{cite journal|vauthors=Pingel J, Lu Y, Starborg T, Fredberg U, Langberg H, Nedergaard A, etal | title=3-D ultrastructure and collagen composition of healthy and overloaded human tendon: evidence of tenocyte and matrix buckling. | journal=J Anat | year= 2014 | volume= 224 | issue= 5 | pages= 548–55 | pmid=24571576 | doi=10.1111/joa.12164 | pmc=3981497}}</ref>

== Diagnosis == thumb|300px|Diagram illustrating tendonitis and tendon rupture Symptoms can vary from aches or pains and local joint stiffness, to a burning that surrounds the whole joint around the inflamed tendon. In some cases, swelling occurs along with heat and redness, and there may be visible knots surrounding the joint. With this condition, the pain is usually worse during and after activity, and the tendon and joint area can become stiff the following day as muscles tighten from the movement of the tendon. Many patients report stressful situations in their life in correlation with the beginnings of pain which may contribute to the symptoms.{{citation needed|date=October 2020}}

=== Medical imaging ===

Ultrasound imaging can be used to evaluate tissue strain, as well as other mechanical properties.<ref name="pmid21030024">{{cite journal |vauthors=Duenwald S, Kobayashi H, Frisch K, Lakes R, Vanderby R |title=Ultrasound echo is related to stress and strain in tendon |journal=J Biomech |volume=44 |issue=3 |pages=424–9 |date=February 2011 |pmid=21030024 |pmc=3022962 |doi=10.1016/j.jbiomech.2010.09.033 }}</ref> Ultrasound-based techniques are becoming more popular because of its affordability, safety, and speed. Ultrasound can be used for imaging tissues, and the sound waves can also provide information about the mechanical state of the tissue.<ref name="pmid22542220">{{cite journal |vauthors=Duenwald-Kuehl S, Lakes R, Vanderby R |title=Strain-induced damage reduces echo intensity changes in tendon during loading |journal=J Biomech |volume=45 |issue=9 |pages=1607–11 |date=June 2012 |pmid=22542220 |pmc=3358489 |doi=10.1016/j.jbiomech.2012.04.004 }}</ref>

==Treatment==

Treatment of tendon injuries is largely conservative. Use of non-steroidal anti-inflammatory drugs (NSAIDs), rest, and gradual return to exercise is a common therapy. A meta-analysis revealed that exercise using weights or a resistance band is more effective than using bodyweight alone. In addition, having rest days is more effective than exercising every day.<ref>{{Cite journal |last1=Pavlova |first1=Anastasia Vladimirovna |last2=Shim |first2=Joanna S. C. |last3=Moss |first3=Rachel |last4=Maclean |first4=Colin |last5=Brandie |first5=David |last6=Mitchell |first6=Laura |last7=Greig |first7=Leon |last8=Parkinson |first8=Eva |last9=Alexander |first9=Lyndsay |last10=Brown |first10=Victoria Tzortziou |last11=Morrissey |first11=Dylan |last12=Cooper |first12=Kay |last13=Swinton |first13=Paul A. |date=2023-10-01 |title=Effect of resistance exercise dose components for tendinopathy management: a systematic review with meta-analysis |url=https://bjsm.bmj.com/content/57/20/1327 |journal=British Journal of Sports Medicine |language=en |volume=57 |issue=20 |pages=1327–1334 |doi=10.1136/bjsports-2022-105754 |issn=0306-3674 |pmid=37169370|pmc=10579176 }}</ref><ref>{{Cite journal |date=15 February 2024 |title=Weights, resistance bands and rest days are best for tendinopathy |url=https://evidence.nihr.ac.uk/alert/weights-resistance-bands-rest-days-best-tendinopathy/ |journal=NIHR Evidence|doi=10.3310/nihrevidence_61938 |url-access=subscription |doi-access=free }}</ref> Resting assists in the prevention of further damage to the tendon. Ice, compression and elevation are also frequently recommended. Physical therapy, occupational therapy, orthotics or braces may also be useful. Initial recovery is typically within two to three days and full recovery is within three to six months.<ref name=AFP2005/> Tendinosis occurs as the acute phase of healing has ended (six to eight weeks) but has left the area insufficiently healed. Treatment of tendinitis helps reduce some of the risks of developing tendinosis, which takes longer to heal.{{citation needed|date=October 2020}}

There is tentative evidence that low-level laser therapy may also be beneficial in treating tendinopathy.<ref name="pmid19708800">{{cite journal |vauthors=Tumilty S, Munn J, McDonough S, Hurley DA, Basford JR, Baxter GD |title=Low level laser treatment of tendinopathy: a systematic review with meta-analysis |journal=Photomedicine and Laser Surgery |volume=28 |issue=1 |pages=3–16 |date=February 2010 |pmid=19708800 |doi=10.1089/pho.2008.2470 |s2cid=10634480 }}</ref> The effects of deep transverse friction massage for treating tennis elbow and lateral knee tendinitis is unclear.<ref>{{cite journal|last1=Loew|first1=Laurianne M|last2=Brosseau|first2=Lucie|last3=Tugwell|first3=Peter|last4=Wells|first4=George A|last5=Welch|first5=Vivian|last6=Shea|first6=Beverley|last7=Poitras|first7=Stephane|last8=De Angelis|first8=Gino|last9=Rahman|first9=Prinon|date=2014-11-08|title=Deep transverse friction massage for treating lateral elbow or lateral knee tendinitis|journal=Cochrane Database of Systematic Reviews|volume=2014 |issue=11|article-number=CD003528|doi=10.1002/14651858.cd003528.pub2|pmid=25380079|issn=1465-1858|pmc=7154576}}</ref>

=== Exercise Therapy === Exercise based rehab is commonly used in the conservative management of tendinopathy. Strengthening exercises targeting the affected tendon, including eccentric, concentric, and isometric contractions, are frequently prescribed in clinical practice. Eccentric loading exercises, which involve muscle contraction while the muscle lengthens, are the most commonly used interventions for conditions such as patellar tendinopathy. A systematic review of randomized controlled trials involving individuals with chronic patellar tendinopathy found low- to very-low-quality evidence regarding the benefits of exercise compared with no treatment, glucocorticoid injections, or surgery. While exercise programs may reduce pain in some cases, studies have generally shown little or no difference in long-term function, pain outcomes, or return-to-sport rates when compared with other interventions.<ref>{{Cite journal |last=Lopes |first=Alexandre D |last2=Rizzo |first2=Rodrigo RN |last3=Hespanhol |first3=Luiz |last4=Costa |first4=Leonardo OP |last5=Kamper |first5=Steven J |date=2025-05-27 |editor-last=Cochrane Central Editorial Service |title=Exercise for patellar tendinopathy |url=http://doi.wiley.com/10.1002/14651858.CD013078.pub2 |journal=Cochrane Database of Systematic Reviews |language=en |volume=2025 |issue=5 |doi=10.1002/14651858.CD013078.pub2}}</ref>

===NSAIDs=== NSAIDs may be used to help with pain.<ref name=AFP2005/> They however do not alter long term outcomes.<ref name=AFP2005/> Other types of pain medication, like paracetamol (acetaminophen), may be just as useful.<ref name=AFP2005/>

===Steroids=== Steroid injections have not been shown to have long term benefits for tendonitis, but appear to improve pain and function in the short term more effectively than other treatments except NSAIDs.<ref>{{cite journal |vauthors=Gaujoux-Viala C, Dougados M, Gossec L |title=Efficacy and safety of steroid injections for shoulder and elbow tendonitis: a meta-analysis of randomised controlled trials |journal=Ann. Rheum. Dis. |volume=68 |issue=12 |pages=1843–9 |date=December 2009 |pmid=19054817 |pmc=2770107 |doi=10.1136/ard.2008.099572 | quote = Conclusions: Steroid injections are well tolerated and more effective for tendonitis in the short-term than pooled other treatments, though similar to NSAIDs. No long-term benefit was shown.}}</ref> They appear to have little benefit in tendinitis of the rotator cuff.<ref>{{cite journal |last1=Mohamadi |first1=A |last2=Chan |first2=JJ |last3=Claessen |first3=FM |last4=Ring |first4=D |last5=Chen |first5=NC |title=Corticosteroid Injections Give Small and Transient Pain Relief in Rotator Cuff Tendinosis: A Meta-analysis. |journal=Clinical Orthopaedics and Related Research |date=January 2017 |volume=475 |issue=1 |pages=232–243 |doi=10.1007/s11999-016-5002-1 |pmid=27469590|pmc=5174041 }}</ref> There are some concerns that they may have negative effects.<ref>{{cite journal |last1=Dean |first1=BJ |last2=Lostis |first2=E |last3=Oakley |first3=T |last4=Rombach |first4=I |last5=Morrey |first5=ME |last6=Carr |first6=AJ |title=The risks and benefits of glucocorticoid treatment for tendinopathy: a systematic review of the effects of local glucocorticoid on tendon. |journal=Seminars in Arthritis and Rheumatism |date=February 2014 |volume=43 |issue=4 |pages=570–6 |doi=10.1016/j.semarthrit.2013.08.006 |pmid=24074644}}</ref>

===Other injections=== There is insufficient evidence on the routine use of injection therapies (autologous blood, platelet-rich plasma, deproteinised haemodialysate, aprotinin, polysulphated glycosaminoglycan, skin derived fibroblasts etc.) for treating Achilles tendinopathy.<ref>{{cite journal|last1=Kearney|first1=RS|last2=Parsons|first2=N|last3=Metcalfe|first3=D|last4=Costa|first4=ML|title=Injection therapies for Achilles tendinopathy.|journal=The Cochrane Database of Systematic Reviews|date=26 May 2015|volume=2015 |issue=5|article-number=CD010960|doi=10.1002/14651858.CD010960.pub2|pmid=26009861|pmc=10804370 |url=https://wrap.warwick.ac.uk/100504/1/WRAP-injection-therapies-Achilles-tendinopathy-Kearney-2015.pdf}}</ref> As of 2014 there was insufficient evidence to support the use of platelet-rich therapies for treating musculoskeletal soft tissue injuries such as ligament, muscle and tendon tears and tendinopathies.<ref>{{cite journal|title=Cochrane Database of Systematic Reviews|last1=Moraes|first1=Vinícius Y|last2=Lenza|first2=Mário|last3=Tamaoki|first3=Marcel Jun|last4=Faloppa|first4=Flávio|last5=Belloti|first5=João Carlos|date=2014-04-29|doi=10.1002/14651858.cd010071.pub3|pmid= 24782334|issue=4|journal=Cochrane Database Syst Rev|volume=2014 |article-number=CD010071|pmc=6464921}}</ref>

==Prognosis== Initial recovery from overuse tendinosis is usually within two to three months, and 80% will recover fully within three to six months.<ref name=AFP2005/>

==Epidemiology== Tendon injury and resulting tendinopathy are responsible for up to 30% of consultations to sports doctors and other musculoskeletal health providers.<ref>{{cite journal|title=Assessing health needs in primary care. Morbidity study from general practice provides another source of information|journal=BMJ|pmid=7787617 | volume=310|issue=6993|date=Jun 1995|page=1534|doi=10.1136/bmj.310.6993.1534d|pmc=2549904|vauthors=McCormick A, Charlton J, Fleming D}}</ref> Tendinopathy is most often seen in tendons of athletes either before or after an injury but is becoming more common in non-athletes and sedentary populations. For example, the majority of patients with Achilles tendinopathy in a general population-based study did not associate their condition with a sporting activity.<ref>{{cite journal|vauthors=de Jonge S, etal |title=Incidence of midportion Achilles tendinopathy in the general population|journal=Br J Sports Med|date=2011|volume=45|issue=13|pages=1026–8|pmid=21926076 |doi=10.1136/bjsports-2011-090342|url=https://repub.eur.nl/pub/30870 |s2cid-access=free |via=RePub |hdl=1765/30870|s2cid=206879020|hdl-access=free |url-status=live |archive-url=https://web.archive.org/web/20231009163141/https://repub.eur.nl/pub/30870/ |archive-date= Oct 9, 2023 }}</ref> In another study the population incidence of Achilles tendinopathy increased sixfold from 1979–1986 to 1987–1994.<ref>{{cite journal | last1=Leppilahti | first1=Juhana | last2=Puranen | first2=Jaakko | last3=Orava | first3=Sakari | title=Incidence of Achilles tendon rupture | journal=Acta Orthopaedica Scandinavica | volume=67 | issue=3 | date=1996 | issn=0001-6470 | doi=10.3109/17453679608994688 | pages=277–279| pmid=8686468 }}</ref> The incidence of rotator cuff tendinopathy ranges from 0.3% to 5.5% and annual prevalence from 0.5% to 7.4%.<ref>{{cite journal|last1=Littlewood|first1=Chris|last2=May|first2=Stephen|last3=Walters|first3=Stephen|date=2013-10-01|title=Epidemiology of rotator cuff tendinopathy: a systematic review|journal=Shoulder & Elbow|language=en|volume=5|issue=4|pages=256–265|doi=10.1111/sae.12028|s2cid=74208378|issn=1758-5740}}</ref>

==Terminology== Tendinitis is a very common, but misleading term. By definition, the suffix "-itis" means "inflammation of". Inflammation<ref>{{cite journal|title=Inflammation|url=https://medical-dictionary.thefreedictionary.com/Inflammation|journal=The Free Dictionary}}</ref> is the body's local response to tissue damage which involves red blood cells, white blood cells, blood proteins with dilation of blood vessels around the site of injury. Tendons are relatively avascular.<ref>{{cite journal|title=avascular|url=https://medical-dictionary.thefreedictionary.com/avascular|journal=The Free Dictionary}}</ref> Corticosteroids are drugs that reduce inflammation. Corticosteroids can be useful to relieve chronic tendinopathy pain, improve function, and reduce swelling in the short term. However, there is a greater risk of long-term recurrence.<ref name="ReesStride2013">{{cite journal|last1=Rees|first1=J. D.|last2=Stride|first2=M.|last3=Scott|first3=A.|title=Tendons - time to revisit inflammation|journal=British Journal of Sports Medicine|volume=48|issue=21|year=2013|pages=1553–1557|issn=0306-3674|doi=10.1136/bjsports-2012-091957|pmid=23476034|pmc=4215290}}</ref> They are typically injected along with a small amount of a numbing drug called lidocaine. Research shows that tendons are weaker following corticosteroid injections.

Tendinitis is still a very common diagnosis, though research increasingly documents that what is thought to be tendinitis is usually tendinosis.<ref>{{cite journal | title = Tendinopathy: Why the Difference Between Tendinitis and Tendinosis Matters|doi=10.3822/ijtmb.v5i1.153 |pmid=22553479 |pmc=3312643 | volume=5 |issue=1 |pages=14–7 | journal=International Journal of Therapeutic Massage & Bodywork: Research, Education, & Practice|year=2012 |last1=Bass |first1=Lmt |doi-access=free }}</ref>

Anatomically close but separate conditions are: *Enthesitis, wherein there is inflammation of the entheses, the sites where tendons or ligaments insert into the bone.<ref>{{cite journal| title=Enthesitis | journal=Best Practice & Research Clinical Rheumatology |vauthors=D'Agostino MA, Olivieri I |publisher=Clinical Rheumatology |volume=20|issue=3 | pages=473–86 | doi=10.1016/j.berh.2006.03.007 | date= June 2006 | pmid=16777577}}</ref><ref>{{cite dictionary |url=https://medical-dictionary.thefreedictionary.com/enthesitis |entry=Enthesitis |dictionary=The Free Dictionary|year=2009| access-date=2010-11-27|title=Enthesitis }}</ref> It is associated with HLA B27 arthropathies such as ankylosing spondylitis, psoriatic arthritis, and reactive arthritis.<ref name="Schett2017">{{cite journal|last1=Schett|first1=G|last2=Lories|first2=RJ|last3=D'Agostino|first3=MA|last4=Elewaut|first4=D|last5=Kirkham|first5=B|last6=Soriano|first6=ER|last7=McGonagle|first7=D|title=Enthesitis: from pathophysiology to treatment|journal=Nature Reviews Rheumatology|date=November 2017|volume=13|issue=12|pages=731–741|doi=10.1038/nrrheum.2017.188|pmid=29158573|s2cid=24724763|type=Review}}</ref><ref name="Schmitt2017">{{cite journal|last1=Schmitt|first1=SK|title=Reactive Arthritis|journal=Infectious Disease Clinics of North America|date=June 2017|volume=31|issue=2|pages=265–277|doi=10.1016/j.idc.2017.01.002|pmid=28292540|type=Review}}</ref> *Apophysitis, inflammation of the bony attachment, generally associated with overuse among growing children.<ref name=Osgood-Schlatter>{{cite web | url=https://orthokids.org/Condition/Osgood-Schlatter-s |title = OrthoKids - Osgood-Schlatter's Disease}}</ref><ref name=Kidshealth>{{cite web|url=https://kidshealth.org/parent/medical/bones/severs_disease.html |title=Sever's Disease |publisher=Kidshealth.org |access-date=2014-04-29}}</ref><ref name="pmid15555843">{{cite journal |vauthors=Hendrix CL |title=Calcaneal apophysitis (Sever disease) |journal=Clinics in Podiatric Medicine and Surgery |volume=22 |issue=1 |pages=55–62, vi |year=2005 |pmid=15555843 |doi=10.1016/j.cpm.2004.08.011}}</ref>

==Research==

The use of a nitric oxide delivery system (glyceryl trinitrate patches) applied over the area of maximal tenderness was found to reduce pain and increase range of motion and strength.<ref>{{cite journal|vauthors=Murrell GA |title=Using nitric oxide to treat tendinopathy |journal=Br J Sports Med |year=2007 |issue=4 |volume=41 |pages=227–31 |pmid =17289859|pmc=2658939 |doi=10.1136/bjsm.2006.034447}}</ref>

A promising therapy involves eccentric loading exercises involving lengthening muscular contractions.<ref name="Rowe-2012">{{cite journal |vauthors=Rowe V, Hemmings S, Barton C, Malliaras P, Maffulli N, Morrissey D |title=Conservative management of midportion Achilles tendinopathy: a mixed methods study, integrating systematic review and clinical reasoning |journal=Sports Med |volume=42 |issue=11 |pages=941–67 |date=November 2012 |pmid=23006143 |doi=10.2165/11635410-000000000-00000 }}</ref>

==Other animals== Bowed tendon is a horseman's term for tendinitis (inflammation) and tendinosis (degeneration), most commonly seen in the superficial digital flexor tendon in the front leg of horses.

Mesenchymal stem cells, derived from a horse's bone marrow or fat, can be used for tendon repair in horses.<ref name="pmid19412395">{{cite journal|vauthors=Koch TG, Berg LC, Betts DH | title=Current and future regenerative medicine - principles, concepts, and therapeutic use of stem cell therapy and tissue engineering in equine medicine. | journal=Can Vet J | year= 2009 | volume= 50 | issue= 2 | pages= 155–65 | pmid=19412395 | pmc=2629419 }}</ref>

==References== {{Reflist}}

{{Medical resources | DiseasesDB = 31624 | ICD11 = {{ICD11|FB55.Z}} | ICD10 = {{ICD10|M|77|9|m|70}} | ICD9 = {{ICD9|726.90}} | ICDO = | OMIM = | MedlinePlus = 001229 | eMedicineSubj = emerg | eMedicineTopic = 570 | MeshID = D052256 }}

Category:Disorders of fascia Category:Inflammations Category:Overuse injuries Category:Pain Category:Wikipedia medicine articles ready to translate