II. Anatomy: Normal Tendon

  1. Tendons
    1. Tightly packed CollagenCollagen fibers produced by tenocytes and tenoblasts
    2. High strength, flexibility and elasticity that can withstand prolonged and repeated load bearing
    3. Tendons have decreased oxygen demand, and heal more slowly than other soft tissue
  2. Collagen fibers
    1. Collagen fibrils organized into budles of fibers
      1. Each bundle organized into larger bundles
    2. Interwoven with other tendon components
      1. Proteoglycans
      2. Elastin
      3. Lipids
  3. Tendon sheath (epitenon)
    1. Contains nerves and vessels supplying tendon
  4. Osteotendinous Junction (Tendon attachment to bone)
    1. Muscle force is transmitted to this site
    2. Site of most Tendon Injury
    3. Tendons are most hypovascular at this site
      1. Osteotendinous junction most prone to Hypoxia
      2. Appears to be important in Tendinopathy development

III. Types: Tendinopathy

  1. Tendinopathy
    1. Tendon Injury with secondary degeneration and decreased healing WITHOUT significant inflammation
    2. Associated with tendon pain and tendon thickening
  2. Tendonitis (Misnomer; Tendinosus or Tendinopathy are typically the more accurate term)
    1. Acute inflammatory Tendinopathy
      1. Implies tendon inflammation, whereas most Tendinopathy chronic injury is degenerative
    2. True Tendonitis at presentation is uncommon
      1. Sudden onset, resolves completely in days to weeks
      2. Most tendon injuries at presentation are chronic
  3. Tendinosus (histologic term)
    1. Describes most chronic tendon overuse injuries
    2. Chronic course over 3-6 months
      1. Incomplete resolution in up to 20%
    3. Associated with chronic degenerative changes
      1. Collagen degenerates into disordered structure
      2. Proteoglycan ground substance increases
      3. Neovascularization
    4. Key related points
      1. NSAIDs do not help and in fact delay healing (non-inflammatory condition)
      2. Absolute rest delays healing (tendons heal best when under some level of tension)

IV. Risk Factors

  1. Intrinsic Factors
    1. Aging
      1. Tendons become stiff, with decreased perfusion, decreased healing and increased degeneration
    2. Anatomic Factors
      1. Muscle Weakness
      2. Inflexibility
      3. Malalignment
      4. Imbalance
    3. Systemic Factors
      1. Tobacco Abuse
      2. Obesity
      3. Diabetes Mellitus
      4. Rheumatologic Disorders (e.g. Gout, Collagen Vascular Disease)
  2. Extrinsic Factors
    1. Corticosteroids
    2. Overuse or misuse of tools, Exercise equipment (often with improper technique)
    3. Lack of protective equipment

VI. History

  1. New or changed activity (esp. repetitive) preceding injury?
  2. Work related injury?
  3. Pain and swelling location, timing and palliative and provocative measures

VII. Exam

  1. See specific examinations for involved region
  2. Symmetric or asymmetric findings?
  3. Evaluate for swelling and tenderness over involved tendons
  4. Passive and active range of motion
  5. Motor Strength
  6. Weigh bearing including arch exam (lower extremity Tendinopathy)

VIII. Symptoms

  1. Gradual onset of localized pain at tendon insertion
  2. Associated with new or increased activity
  3. Initially, limited to sharp pain during activity
  4. Later, dull pain may persist even at rest

IX. Imaging

  1. XRay
    1. Imaging is not typically needed in acute Tendinopathy without Trauma or suspicion for Fracture
    2. Consider when evaluating differential diagnosis of pain source, especially with persistent pain >6 weeks
  2. Ultrasound
    1. Most tendons are well visualized on Ultrasound and offer a dynamic, real-time observation
    2. However, Ultrasound is highly operator dependent
    3. See Shoulder Ultrasound
    4. See Elbow Ultrasound
    5. See Wrist Ultrasound
    6. See Hip Ultrasound
    7. See Knee Ultrasound
    8. See Ankle Ultrasound
  3. MRI
    1. Consider in persistent and refractory course in which xray and Ultrasound are non-diagnostic
    2. Consider that even MRI, which is operator independent, is still non-specific (Test Specificity 70%)

X. Management

  1. RICE-M
  2. Local Cold Therapy (Cryotherapy)
  3. Orthotics (e.g. Tennis Elbow counterforce strap)
  4. Stretching and Strengthening Exercises
    1. Start after acute pain has resolved
    2. Eccentric Exercises (loading Muscles/tendons as they are being lengthened) are preferred
  5. Medications to consider at initial onset (acute phase)
    1. Brief NSAID course for 7-14 days (systemic or Topical NSAID)
    2. Local Corticosteroid Injection
      1. May be more effective than NSAIDs in acute pain
      2. Does not change longterm course of Tendinopathy
      3. Risk of delayed healing
      4. Risk of tendon rupture (esp. with repeated injection), but relatively rare complication (<1%)
        1. Coombes (2010) Lancet 376(9754): 1751-67 [PubMed]
  6. Medications to consider for persistent and refractory Tendinopathy
    1. Topical Nitroglycerin
      1. Usage
        1. May reduce pain with activity and improve strength
        2. Apply one quarter of a 5 mg Nitroglycerin patch daily to affected area
        3. Requires a Nitroglycerin-free period of 12 hours per day
        4. Systemic Nitroglycerin adverse effects may occur (e.g. Headache)
      2. Efficacy: Mixed Results
        1. Some studies have shown improved pain, strength and patient satisfaction
          1. Gambito (2010) Arch Phys Med Rehabil 91(8): 1291-305 [PubMed]
        2. Other studies show not significantly better than Placebo in acute or chronic Tendinopathy
          1. Loescher (2022) Am Fam Physician 105(2): 196-7 [PubMed]
  7. Sports medicine techniques (consider if lack of improvement in 8 to 12 weeks with other measures)
    1. Tendon fenestration
      1. Rapidly move needle through area of injured tendon resulting in micro-Trauma
      2. Results in local bleeding and regenerative factor infiltration into the area
      3. May be performed with or without Corticosteroid Injection
    2. Dry needling
      1. Thin needle placed within thickened or painful area of Muscle or tendon
      2. May be performed with electrical stimulation
    3. Platelet-rich plasma injections
      1. Growth factors released from Platelets aid tissue rapair and regeneration
      2. Should be combined with a physical therapy directed program
  8. Physical Therapy modalities
    1. Local Therapeutic Ultrasound
    2. Iontophoresis and Phonophoresis
    3. Extracorporeal Shock Wave Therapy (ESWT)

XI. Prevention

  1. Prevent overuse injury
    1. See Athletic Injury
    2. See Occupational Injury
  2. Lower Extremiy Tendinopathy
    1. Ensure Proper Shoe Fit (or Running Shoe)
    2. Avoid provocative factors (e.g. high heals)
  3. Upper Extremity Tendinopathy
    1. See Overuse Syndromes of the Hand and Wrist

XII. Prognosis

  1. Refractory course to 3-6 months of conservative management in 10-45% of Tendinopathy patients

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Related Studies

Ontology: Tendinitis (C0039503)

Definition (MEDLINEPLUS)

Tendons are flexible bands of tissue that connect muscles to bones. They help your muscles move your bones. Tendinitis is the severe swelling of a tendon.

Tendinitis usually happens after repeated injury to an area such as the wrist or ankle. It causes pain and soreness around a joint. Some common forms of tendinitis are named after the sports that increase their risk. They include tennis elbow, golfer's elbow, pitcher's shoulder, swimmer's shoulder, and jumper's knee.

Doctors diagnose tendinitis with your medical history, a physical exam, and imaging tests. The first step in treatment is to reduce pain and swelling. Rest, wrapping or elevating the affected area, and medicines can help. Ice is helpful for recent, severe injuries. Other treatments include ultrasound, physical therapy, steroid injections, and surgery.

Definition (NCI) Inflammation of a tendon, usually resulting from an overuse injury. It is characterized by swelling of the tendon, tenderness around the inflamed tendon, and pain while moving the affected area of the body.
Definition (MSH) Inflammation of TENDONS. It is characterized by the degeneration of tendons accompanied by an inflammatory repair response, fibroblastic proliferation, and formation of granulation tissue. Tendinitis is not a clinical diagnosis and can be confirmed only by histopathological findings.
Concepts Disease or Syndrome (T047)
MSH D052256
ICD10 M77.9
SnomedCT 268091003, 202893001, 312785002, 267996008, 156665008, 34840004
French TENDINITE, Tendinite, Ténosite
English TENDINITIS, tendonitis (diagnosis), tendonitis, Tendinitis NOS, Tendinitis NOS (disorder), Tendonitis NOS, Tendon inflamed, Inflammatory disorder of tendon, Tendinitis (disorder), tendinitis, disease (or disorder); tendon, inflammatory, inflammation; tendon, tendon; disorder, inflammatory, tendon; inflammation, Tendinitis, NOS, Tendonitis, NOS, Tendinitides, Tendinitis, Tendonitides, Tendonitis
Portuguese TENDINITE, Tendinite
Spanish TENDINITIS, Tendinitis, tendinitis, SAI (trastorno), tendinitis, SAI, tendinitis (trastorno), tendinitis, tendonitis
German TENDINITIS, Tendinitis, Tendonitis, Sehnenentzündung
Japanese 腱炎, ケンエン
Czech tendinitida, Tendinitida
Italian Tendinite
Hungarian Tendinitis
Norwegian Tendinitt
Dutch aandoening; pees, inflammatoir, ontsteking; pees, pees; aandoening, inflammatoir, pees; ontsteking, tendinitis

Ontology: Tendon Injuries (C0039504)

Definition (MSHCZE) Poranění fibrózních (vazivových) provazců pojivové tkáně, které připojují svaly ke kostem a jiným strukturám. R
Definition (MSH) Injuries to the fibrous cords of connective tissue which attach muscles to bones or other structures.
Definition (CSP) damage inflicted on any tendon as the direct or indirect result of an external force, with or without disruption of structural continuity.
Concepts Injury or Poisoning (T037)
MSH D013708
SnomedCT 240037007
English Injuries, Tendon, Injury, Tendon, Tendon Injuries, TENDON INJURY, Tendon Injury, tendon injury, INJ TENDON, TENDON INJ, Tendon Injuries [Disease/Finding], tendon injuries, injury tendons, injuries tendons, injuries tendon, tendon injury (diagnosis), Tendon injury, Injury of tendon, Tendon injury (disorder), injury; tendon, tendon; injury
Italian Lesione di tendine, Lesioni del tendine
Swedish Senskador
Japanese ケンソンショウ, 腱外傷, 腱損傷, 損傷-腱
Czech šlachy - poranění, Poranění šlachy
Finnish Jännevammat
French ATTEINTE TENDINEUSE, Blessures des tendons, Blessures du tendon, Blessures tendineuses, Lésion d'un tendon, Traumatismes tendineux, Traumatismes du tendon, Lésions traumatiques des tendons, Traumatismes des tendons
Portuguese LESAO DO TENDAO, Lesões dos Tendões, Lesão traumática de tendão, Traumatismos dos Tendões
German SEHNENVERLETZUNG, Sehnenverletzung, Sehnenverletzungen
Polish Urazy ścięgien
Hungarian Ínsérülés
Norwegian Skader, sene, Seneskader, Tendoskader, Skader, tendo
Spanish Lesiones de los Tendones, lesión de tendón (trastorno), lesión de tendón, lesión tendinosa, Lesión traumática de tendón, Traumatismos de los Tendones
Dutch letsel; pees, pees; letsel, peesletsel, Peestrauma, Peestraumata, Trauma, pees-, Traumata, pees-

Ontology: Muscle strain (C0080194)

Concepts Injury or Poisoning (T037)
MSH D013180
ICD10 M62.6
SnomedCT 269324003, 203094001, 367127009, 156726002, 157257005, 48532005
English Muscle strain, strain (diagnosis), strain, strain of unspecified muscle, strain of unspecified muscle (diagnosis), muscle pull, muscles pull, muscles pulled, muscles strained, strain muscle, pulled muscle, muscle pulled, muscle pulls, muscles pulling, strained, strains, muscle strained, pull muscle, Strain;muscle(s), muscles strains, muscle pull or tear, muscle pulling, muscle strains, muscles strain, Muscle Strain, Muscle strain (finding), Strain, Pulled muscle, Muscle strain (disorder), muscle; strain, strain; muscle, Strain, NOS, Strains, muscle strain
Italian Stiramento muscoloare, Muscolo stirato, Stiramento
Dutch verrekking, verrekte spier, overbelasting; spier, spier; overbelasting, Spierverrekking, spierverrekking
French Etirement de muscle, Foulure, Foulures, Claquage de muscle
German Zerrung, gezerrter Muskel, Zerrungen, Muskelzerrung
Portuguese Luxação, Músculo distendido, Luxação muscular
Spanish Distensión muscular, distensión muscular (trastorno), distensión muscular, Desgarre muscular
Czech Natažení, namožení svalu, Natažení, namožení, Natažený sval, natažení, namožení
Korean 근육긴장
Japanese ニクバナレ, 肉離れ
Hungarian Izomhúzódás, Húzódás, Izomrándulás
Norwegian Forstrekking

Ontology: Tendinopathy (C1568272)

Definition (MSH) Clinical syndrome describing overuse tendon injuries characterized by a combination of PAIN, diffuse or localized swelling, and impaired performance. Distinguishing tendinosis from tendinitis is clinically difficult and can be made only after histopathological examination.
Concepts Disease or Syndrome (T047)
MSH D052256
English Tendinopathy, Tendinopathy [Disease/Finding], Tendinopathies
Swedish Tendinopati
Czech tendinopatie
Finnish Tendinopatia
Polish Zapalenie ścięgna, Choroby ścięgna
Japanese 腱炎, 腱障害
Norwegian Senebetennelse, Sene degenerasjon
Spanish Entesiopatía, Tendinopatía
Portuguese Tendinopatia
German Tendopathie
Italian Tendinopatia
French Tendinopathie

Ontology: Tendinosis (C1568363)

Definition (MSH) A disorder of TENDONS characterized by COLLAGEN degeneration, other changes to tenocytes and the EXTRACELLULAR MATRIX, and a lack of inflammatory cells. It is caused by aging, microtrauma, or vascular compromise. Tendinosis is not a clinical diagnosis and can be confirmed only by histopathological findings.
Concepts Disease or Syndrome (T047)
MSH D052256
SnomedCT 430671000124105
English Tendinosis, Tendinosis (finding), Tendinoses
Dutch tendinose
Portuguese Tendinose, Tendino
Japanese 腱症, ケンショウ
Czech tendinóza, Tendinóza
Spanish Tendinosis
French Tendinose
German Tendinose
Hungarian Tendinosis
Norwegian Tendinose
Italian Tendinosi