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Flexor Hallucis Longus Tendinopathy

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Other Names

  • FHL Tendonitis
  • FHL Tendinopathy
  • Flexor Hallucis Longus Tendinopathy
  • FHL Rupture
  • FHL Tenosynovitis
  • FHL Laceration
  • Dancer's Tendonitis
  • Stenosing tenosynovitis of the Flexor Hallucis Longus
  • Intersection Syndrome Foot
  • Intersection Syndrome of the Foot


  • This page refers to injuries to the Flexor Hallucis Longus (FHL) tendon
    • Although generally an overuse syndrome, this page includes tendon ruptures, lacerations and other tendinopathies



  • Rare and poorly described in the literature


  • General
    • Can occur as a result of impingement of the FHL tendon along the posterior ankle joint
    • FHL has been called the 'Achilles of the foot' due its role controlling midfoot supination and pronation
  • Intersection Syndrome Foot
    • Overall, poorly understood
    • Characterized by fibrosis of the intersection between the FHL and the FDL tendons at the Knot of Henry
    • Potential causes
      • Acute or chronic repetitive hyperextension of the 1st metatarsophalangeal joint
      • Partial tear of the FHL tendon at the knot


  • Overuse/ Tendinosis
    • Activities involving maximal plantarflexion, sports requiring repetitive forefoot push-off
  • In dancers/ ballet
    • Provoked by the recurrent movement caused by changing position from a plié position to a relevé position
      • Plié is a French term meaning to bend, relevé, is a ballet term meaning “raised.”[1]
      • The term relevé explains the action when a dancer rises up on their toes
    • Loaded hyperplantarflexed positioning of the ankle experienced in ballet (particularly en pointe)
    • Can cause direct compression of the FHL through kinking of the tendon where it enters the fibro-osseous tunnel posterior to the talus
  • FHL Laceration
    • Acute laceration


  • Fibro-osseous tunnel in tenosynovitis
    • Tends to occur in the fibro-osseous tunnel
    • Hypothesis 1[2]
      • Relative incongruity between the FHL and the fibro-osseous tunnel when the foot is in full plantarflexion
      • Could lead to abnormal stresses on the tendon when it is under extreme tension such as dancing on en pointe
    • Hypothesis 2
      • Distal excursion of the tendon during ankle and hallux dorsiflexion
      • Low-lying muscle belly just proximal to the fibro-osseous tunnel
      • As the FHL moves distally into the fibro-osseous tunnel, the muscle mass gets jammed into the tunnel, leading to inflammation or swelling

Associated Conditions


Risk Factors

  • Sports (classic)
    • Dancers[3]
    • Gymnasts
  • Sports (case reports)
    • Soccer referee[4]
    • Long distance runner[5]
  • Biomechanical
    • Excessive plantarflexion

Differential Diagnosis

Differential Diagnosis Ankle Pain

Differential Diagnosis Foot Pain

Clinical Features

  • History
    • In overuse syndromes, the onset of symptoms is insidious
    • Patients often report posteromedial ankle and, much less commonly, great toe pain
    • Pain is greatest while performing a plie position, during which the FHL tendon is stretched
    • Great toe locking with active range of motion
    • Crepitus along the posterior medial ankle
  • Physical Exam: Physical Exam Foot
    • Tenderness to direct palpation over the musculotendinous junction of the FHL
    • Pain with resisted flexion of the hallux IP joint[6]
    • Pain with forced plantarflexion of the ankle
    • Great toe 'triggers' with active or passive motion (no tenderness at the level of the 1st metatarsal head)
    • Pseudo Hallux Rigidus may be present, demonstrated by limitation of great toe dorsiflexion with knee extended, ankle dorsiflexed
  • Special Tests
    • Tomasen Test: Assess 1st MTP motion in maximal plantarflexion with moderate ankle dorsiflexion




  • Findings
    • Fluid around tendon (tenosynovitis) of the tendon sheath at the level of the ankle
    • Intrasubstance tendinous signal
    • In laceration, tendon ends may be retracted
  • In one study, 28/34 patients had MRI findings confirming the clinical exam[7]
  • Potential findings of 'Intersection Syndrome'
    • Peritendinous edema and fluid around the flexor hallucis longus at the level of the navicular and medial cuneiform (location of knot of henry)
    • Peritendinous edema and fluid involving the flexor hallucis longus (FHL) and flexor digitorum longus (FDL)


  • Dynamic ultrasound
    • Allows real time testing of FHL tendon through range of motion


  • Not applicable



  • Indications
    • First line in nearly all cases
  • Activity modification
    • Avoid provoking activities until symptoms are resolved
  • Correcting biomechanics (Dancers)
    • Reduce turnout of the hip so the dancer is working directly over the foot
    • Avoid hard floors when possible
    • Physical therapy with emphasis on strengthening the body's core
    • Firm, well-fitted shoes
    • Consider modification of mechanics
  • Immobilization
  • Orthotics
    • Emphasis on arch support
  • Physical Therapy
    • Emphasis on trunk (body and abdominal), back and pelvic muscles
    • Calf, FHL stretching exercises
  • Prevention
    • Preventative conditioning is important for dancers
    • Important to maintain conditioning during breaks, layoffs
    • Strength, flexibility and proprioception
    • Well fitting shoes when appropriate[8]
    • Use of floors with good resiliency and friction characteristics
    • Proper biomechanics


  • Indications
    • Acute FHL tendon laceration
    • Progressive tendonitis that fails nonoperative management

Rehab and Return to Play


  • Needs to be updated

Return to Play/ Work

  • Needs to be updated

Complications and Prognosis


  • Unknown


See Also


  1. Mira NO, Marulanda AF, Pena AC, Torres DC, Orrego JC. Study of Ballet Dancers During Cou-De-Pied Derrière with Demi-Plié to Piqué Arabesque. Journal of Dance Medicine & Science. 2019 Dec 15;23(4):150-8.
  2. Gould, N : Stenosing tenosynovitis of the flexor hallucis longus tendon at the great toe. Foot Ankle 2:46–48, 1981.
  3. Hamilton, WG, Geppert, MJ, Thompson, FM: Pain in the posterior aspect of the ankle in dancers. Differential diagnosis and operative treatment, J. Bone Joint Surg. 78A:1491–1500, 1996.
  4. Cooper, ME, Wolin, PM: Os trigonum syndrome with flexor hallucis longus tenosynovitis in a professional football referee, Med. Sci. Sports Exerc. 31:S493–S496, 1999.
  5. Romash, MM : Closed rupture of the flexor hallucis longus tendon in a long distance runner: report of a case and review of the literature, Foot Ankle Int. 15:433–436, 1994.
  6. owley KM, Jarvis DN, Kurihara T, Chang YJ, Fietzer AL, Kulig K. Toe flexor strength, flexibility and function and flexor hallucis longus tendon morphology in dancers and non-dancers. Medical problems of performing artists. 2015 Sep 1;30(3):152-6
  7. Michelson, James, and Laura Dunn. "Tenosynovitis of the flexor hallucis longus: a clinical study of the spectrum of presentation and treatment." Foot & ankle international 26.4 (2005): 291-303.
  8. Walter HL, Docherty CL, Schrader J. Ground reaction forces in ballet dancers landing in flat shoes versus pointe shoes. Journal of Dance Medicine & Science. 2011 Jun 15;15(2):61-4.
Created by:
John Kiel on 26 June 2019 22:07:58
Last edited:
4 October 2022 12:39:31