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Condition/Disorder Synonyms

  • Achilles tendinitis

  • Achilles tendonitis

  • Achilles paratenonitis

ICD-9-CM Code1

  • 726.71 Achilles bursitis or tendonitis

ICD-10-CM Code2

  • M76.60 Achilles tendinitis, unspecified leg

Preferred Practice Pattern3

Key Features


  • Insertional Achilles tendinitis: fibers in middle portion of the tendon breakdown, degenerate, swell, thicken

  • Noninsertional Achilles tendonitis: pain in lower portion of heel at tendon attachment

  • Pain common at midportion of Achilles tendon

  • Typically lacks presence of inflammatory cells, probably more tendonosis then tendonitis

  • Typically associated with tissue degeneration

    • Two types

      • Lipoid: fatty tissue deposited in the tendon

      • Mucoid: conversion of tendon in softer material with gray or brown appearance

    • Thickening of tendon

    • Neovascularization

    • Increased presence of varicose nerve fibers

      • Most likely source of pain

Essentials of Diagnosis

  • Patient history and clinical examination

  • Ultrasound or MRI imaging

General Considerations

  • Address training errors and biomechanics deficits to prevent recurrence


  • People participating in athletic activity; condition can also occur in sedentary individuals

    • Runners: 7 to 9% prevalence4

  • Age: between 30 to 50 years of age (median)4

  • Sex: Males more than females4

  • Onset more common during training vs. competitive event

Clinical Findings

Signs and Symptoms

  • Pain with palpation of tendon 2 to 6 cm proximal to the insertion

  • Pain back of the heel

  • Tenderness changes position with tendon movement during dorsiflexion and plantarflexion (arc sign)

  • Increased swelling throughout the day

  • Thickening of the tendon

  • Decreased dorsiflexion range of motion (ROM)

  • Decreased gastrocnemius strength

  • Greater pronation/calcaneal varus and faster rate of max. pronation

  • Decreased plantar flexion strength and endurance verse uninvolved side

Functional Implications

  • Inability to climb stairs or ladder

  • Inability to push-off during ambulation

  • Decreased stride length during ambulation

Possible Contributing Causes

  • Intrinsic risk factors

    • Decreased dorsiflexion ROM

    • Decreased gastrocnemius strength

    • Greater pronation/Calcaneal varus and faster rate of max. pronation

    • Comorbidities

    • Obesity

    • Diabetes

    • Hyperlipidemia

    • Hypertension

  • Extrinsic risk factors

    • Training errors

      • Sudden increase in mileage or intensity or incline

      • Return from inactivity

    • Environmental factors

      • High incidence with training in cold weather

    • Faulty equipment

Differential Diagnosis

  • Achilles tendon rupture

  • Achilles tendon partial tear

  • Bone spur

  • Sural nerve pathology

  • Retrocalcaneal bursitis

  • Posterior ankle impingement

  • Accessory soleus muscle

  • S1 radiculopathy

  • Achilles tendon ossification

  • Achilles enthesopathy

  • Os trigonum

  • Systemic inflammatory disease

  • Xanthoma of the tendon: accumulation of cholesterol in patients with familial hypercholesterolemia

Means of Confirmation or Diagnosis


  • Ultrasonography: (sn=85%, sp=49%)

  • MRI: (sn=95%, ...

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