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Chronic Ankle Instability

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Other Names

  • Chronic Lateral Ankle Instability (CLAI)
  • Recurrent ankle sprain


  • This page refers to chronic instability of the Ankle Joint
    • Often termed 'Chronic Lateral Ankle Instability (CLAI)'



  • Ankle injuries account for 10-30% of all sports injuries[1]
  • Prevalence
    • Overall 25% (range 7% to 53%)[2]
    • With a history of ankle sprains 46% (range 9% to 76%)[2]


  • General
    • Vast majority of cases associated with preceding lateral ankle sprain(s) with failure to recover at least 6 weeks after injury
    • Ankle can not maintain mechanical, functional performance
    • Injury to ATFL and CFL play critical role in generating CLAI[3]
    • Can be difficult to distinguish ankle instability from subtalar instability
  • Definition
    • Partial or complete incompetence of the ATFL, CFL, or PTFL
    • The ATFL is most commonly injured, followed by CFL (20%), and PTFL (<10%)[4]
  • Functional instability
    • Depends on patient generated reports or complaints without a clear anatomical deficit
    • Characterized by impaired proprioception, diminished neuromuscular control, compromised strength, decreased postural control, tight Achilles tendon and weak peroneal muscles[5]
    • No clinical or radiographic evidence of instability
  • Mechanical instability
    • Instability identified on physical examination and radiographic evaluation
    • Characterized by objective ligament laxity
  • Mixed instability
    • Most cases of CLAI likely a combination of both mechanical and functional instability
  • Rotational ankle instability (RAI)
    • Some CLAI patients have a partial deltoid injury
    • Described as a combination of lesions in the medial (anterior deltoid ligament) and lateral ligament complex
    • Increase in talar rotation due to deltoid "open book" tear of the most anterior component

Associated Conditions


Risk Factors

Differential Diagnosis

Clinical Features

  • History
    • History of recurrent ankle sprains or severe inversion injury
    • They may describe the ankle as rolling or giving way
    • Often avoid provocative activities (weight bearing, exercise, uneven surfaces)
    • Associated symptoms in include pain, swelling, occasionally locking
  • Physical Exam: Physical Exam Ankle
    • There may be swelling aroound the lateral ankle
    • Tenderness at the ligamentous attachments of ATFL, CFL, etc
    • Evaluate for Hindfoot Varus, midfoot cavus
  • Special Tests



  • Standard Radiographs Ankle
  • Stress Radiographs Ankle
    • Performed while performing either an anterior drawer (AD) or talar tilt (TT) stress to the joint
    • AD: anterior translation of 10 mm or at least a 5-mm side-to-side difference when comparing the injured and uninjured ankles
    • TT: absolute TT of more than 10° or at least a 5° difference between ankles has been reported to correlate with ankle instability
    • When compared to cadaveric measurements using an Optotrak 3D sensor system, stress views underestimate displacement and angular values[7]
    • Instability on TT appears to correlate with MRI findings (need citation)


  • Reliable, validated for surgical decision making[8]
    • Sensitivity for identifying ATFL abnormality
    • Anticipates perioperative surgical technique in 90% of patients (repair or reconstruction)
  • Jolman et al retrospective analysis of MRI for CLAI[9]
    • Sensitivity: 82.6%
    • Specificity: 53.3%


  • Dynamic ultrasound can be used to evaluate ligaments, joint
  • Cho et al compared preoperative dynamic US to stress XR, MRI in 28 patients who underwent arthroscopic repair[10]
    • 100% of patients had a lax, wavy ATFL
    • Affected ATFL stretched to an average of 2.8 ± 0.3 cm under stress compared with only 2.3 ± 0.2 cm on the unaffected side
    • The authors could identify no significant difference in ATFL resting length between the injured and uninjured sides (P = 0.777)


  • Not applicable



  • Indications
    • Majority of cases initially
    • Especially true for cases that are thought to be primarily functional
  • Physical Therapy
    • Emphasis on neuromuscular and proprioceptive training
    • Neuromuscular training found to be effective in short term, unknown in long term[11]
  • Ankle Orthotics


  • Indications
    • Failure of conservative measures
    • Significant mechanical instability
  • Technique
    • Gould modification of Brostrom anatomic reconstruction
    • Tendon transfer and tenodesis (Watson-Jones, Chrisman-Snook, Colville, Evans)

Rehab and Return to Play


  • Needs to be updated

Return to Play/ Work

  • Needs to be updated

Complications and Prognosis


  • Nonoperative management
    • Patients with functional CLAI benefit more than mechanical CLAI with nonoperative management
    • Approximately 50% of athletes with functional CLAI will improve with conservative therapy (need citation)
  • Delay in surgical intervention
    • Initial conservative management delaying surgical intervention has not been associated with adverse outcomes (need citation)
  • Anatomic repair
    • Good or excellent results in 85% of patients[12]
  • Predictors of poor surgical outcome
    • Poor tissue[13]
    • Long-standing ankle instability
    • Cavovarus foot deformity
    • Ligamentous laxity


  • Postoperative
    • Wound complications
      • About 4% of nonanatomic tenodesis, 1.6% after anatomic repair[14]
    • Stiffness
    • Recurrent instability
    • Nerve problems
      • 9.7% for nonanatomic tenodesis, 3.8% for anatomic repair, and 1.9 for anatomic tenodesis[14]

See Also


  1. Hølmer P, Søndergaard L, Konradsen L, Nielsen PT, Jørgensen LN. Epidemiology of sprains in the lateral ankle and foot. Foot Ankle Int. 1994;15:72–4.
  2. 2.0 2.1 Lin, Chiao-I., et al. "The epidemiology of chronic ankle instability with perceived ankle instability-a systematic review." Journal of Foot and Ankle Research 14.1 (2021): 1-11.
  3. Bonnel F, Toullec E, Mabit C, Tourné Y, SOFCOT: Chronic ankle instability: Biomechanics and pathomechanics of ligaments injury and associated lesions. Orthop Traumatol Surg Res 2010;96:424-432.
  4. Espinosa N, Smerek J, Kadakia AR, Myerson MS. Operative management of ankle instability: reconstruction with open and percutaneous methods. Foot Ankle Clin. 2006;11:547-65.
  5. Coughlin MJ, Schenck RC, Jr, Grebing BR, Treme G. Comprehensive reconstruction of the lateral ankle for chronic instability using a free gracilis graft. Foot Ankle Int. 2004;25:231–41.
  6. Helgeson K. Examination and intervention for sinus tarsi syndrome. N Am J Sports Phys Ther. 2009;4:29–37.
  7. Hoffman E, Paller D, Koruprolu S, et al.: Accuracy of plain radiographs versus 3D analysis of ankle stress test. Foot Ankle Int 2011;32:994-999.
  8. Morvan A, Klouche S, Thes A, Hardy P, Bauer T: Reliability and validity of preoperative MRI for surgical decision making in chronic lateral ankle instability. Eur J Orthop Surg Traumatol 2018;28:713-719.
  9. Jolman S, Robbins J, Lewis L, Wilkes M, Ryan P: Comparison of magnetic resonance imaging and stress radiographs in the evaluation of chronic lateral ankle instability. Foot Ankle Int 2017;38:397-404.
  10. Cho JH, Lee DH, Song HK, Bang JY, Lee KT, Park YU: Value of stress ultrasound for the diagnosis of chronic ankle instability compared to manual anterior drawer test, stress radiography, magnetic resonance imaging, and arthroscopy. Knee Surg Sports Traumatol Arthrosc 2016;24:1022-1028.
  11. de Vries, Jasper S., et al. "Interventions for treating chronic ankle instability." Cochrane Database of Systematic Reviews 8 (2011).
  12. Bell SJ, Mologne TS, Sitler DF, Cox JS. Twenty-six-year results after Broström procedure for chronic lateral ankle instability. Am J Sports Med. 2006;34:975–8.
  13. Nakata K, Shino K, Horibe S, Natsu-Ume T, Mae T, Ochi T. Reconstruction of the lateral ligaments of the ankle using solvent-dried and gamma-irradiated allogeneic fascia lata. J Bone Joint Surg Br. 2000;82:579–82.
  14. 14.0 14.1 Sammarco VJ. Complications of lateral ankle ligament reconstruction. Clin Orthop Relat Res. 2001;391:123–32.
Created by:
John Kiel on 7 July 2019 08:14:28
Last edited:
3 October 2022 23:48:16