Functional instability: subjective feeling of ankle instability or ankle "giving way"
Mechanical instability: ankle movement beyond physiologic limit of ROM
Instability can be demonstrated on physical exam or stress radiography
Instability may be present with inversion, eversion, or rotation of ankle
Subtalar joint largely refers to posterior subtalar joint (PSTJ) in this chapter: subtalar instability may affect both anterior and posterior subtalar joints, but imaging manifestations are visible at PSTJ
IMAGING
General Features
Radiographic Findings
MR Findings
Imaging Recommendations
DIFFERENTIAL DIAGNOSIS
PATHOLOGY
General Features
Staging, Grading, & Classification
Relevant Anatomy
CLINICAL ISSUES
Presentation
Natural History & Prognosis
Treatment
DIAGNOSTIC CHECKLIST
Consider
Image Interpretation Pearls
Selected References
Hur ES et al: Lateral Ligament instability: review of pathology and diagnosis. Curr Rev Musculoskelet Med. 13(4):494-500, 2020
Zeng G et al: Open Broström-Gould repair vs arthroscopic anatomical repair of the anterior talofibular ligament for chronic lateral ankle instability. Foot Ankle Int. 41(1):44-9, 2020
Yoon DY et al: Differences between subtalar instability and lateral ankle instability focusing on subtalar ligaments based on three dimensional isotropic magnetic resonance imaging. J Comput Assist Tomogr. 42(4):566-73, 2018
Aynardi M et al: Subtalar instability. Foot Ankle Clin. 20(2):243-52, 2015
Burrus MT et al: Predictors of peroneal pathology in Broström-Gould ankle ligament reconstruction for lateral ankle instability. Foot Ankle Int. 36(3):268-76, 2015
Barg A et al: Subtalar instability: diagnosis and treatment. Foot Ankle Int. 33(2):151-60, 2012
Weindel S et al: Subtalar instability: a biomechanical cadaver study. Arch Orthop Trauma Surg. 130(3):313-9, 2010
Ferran NA et al: Ankle instability. Sports Med Arthrosc. 17(2):139-45, 2009
Alparslan L et al: Lateral ankle instability: MR imaging of associated injuries and surgical treatment procedures. Semin Musculoskelet Radiol. 12(4):346-58, 2008
Kirby AB et al: Magnetic resonance imaging findings of chronic lateral ankle instability. Curr Probl Diagn Radiol. 34(5):196-203, 2005
Hintermann B et al: Medial ankle instability: an exploratory, prospective study of fifty-two cases. Am J Sports Med. 32(1):183-90, 2004
Michelson J et al: The effect of ankle injury on subtalar motion. Foot Ankle Int. 25(9):639-46, 2004
Hintermann B et al: Arthroscopic findings in patients with chronic ankle instability. Am J Sports Med. 30(3):402-9, 2002
Keefe DT et al: Subtalar instability. Etiology, diagnosis, and management. Foot Ankle Clin. 7(3):577-609, 2002
Larsen E et al: Association of ankle instability and foot deformity. Acta Orthop Scand. 61(2):136-9, 1990
Functional instability: subjective feeling of ankle instability or ankle "giving way"
Mechanical instability: ankle movement beyond physiologic limit of ROM
Instability can be demonstrated on physical exam or stress radiography
Instability may be present with inversion, eversion, or rotation of ankle
Subtalar joint largely refers to posterior subtalar joint (PSTJ) in this chapter: subtalar instability may affect both anterior and posterior subtalar joints, but imaging manifestations are visible at PSTJ
IMAGING
General Features
Radiographic Findings
MR Findings
Imaging Recommendations
DIFFERENTIAL DIAGNOSIS
PATHOLOGY
General Features
Staging, Grading, & Classification
Relevant Anatomy
CLINICAL ISSUES
Presentation
Natural History & Prognosis
Treatment
DIAGNOSTIC CHECKLIST
Consider
Image Interpretation Pearls
Selected References
Hur ES et al: Lateral Ligament instability: review of pathology and diagnosis. Curr Rev Musculoskelet Med. 13(4):494-500, 2020
Zeng G et al: Open Broström-Gould repair vs arthroscopic anatomical repair of the anterior talofibular ligament for chronic lateral ankle instability. Foot Ankle Int. 41(1):44-9, 2020
Yoon DY et al: Differences between subtalar instability and lateral ankle instability focusing on subtalar ligaments based on three dimensional isotropic magnetic resonance imaging. J Comput Assist Tomogr. 42(4):566-73, 2018
Aynardi M et al: Subtalar instability. Foot Ankle Clin. 20(2):243-52, 2015
Burrus MT et al: Predictors of peroneal pathology in Broström-Gould ankle ligament reconstruction for lateral ankle instability. Foot Ankle Int. 36(3):268-76, 2015
Barg A et al: Subtalar instability: diagnosis and treatment. Foot Ankle Int. 33(2):151-60, 2012
Weindel S et al: Subtalar instability: a biomechanical cadaver study. Arch Orthop Trauma Surg. 130(3):313-9, 2010
Ferran NA et al: Ankle instability. Sports Med Arthrosc. 17(2):139-45, 2009
Alparslan L et al: Lateral ankle instability: MR imaging of associated injuries and surgical treatment procedures. Semin Musculoskelet Radiol. 12(4):346-58, 2008
Kirby AB et al: Magnetic resonance imaging findings of chronic lateral ankle instability. Curr Probl Diagn Radiol. 34(5):196-203, 2005
Hintermann B et al: Medial ankle instability: an exploratory, prospective study of fifty-two cases. Am J Sports Med. 32(1):183-90, 2004
Michelson J et al: The effect of ankle injury on subtalar motion. Foot Ankle Int. 25(9):639-46, 2004
Hintermann B et al: Arthroscopic findings in patients with chronic ankle instability. Am J Sports Med. 30(3):402-9, 2002
Keefe DT et al: Subtalar instability. Etiology, diagnosis, and management. Foot Ankle Clin. 7(3):577-609, 2002
Larsen E et al: Association of ankle instability and foot deformity. Acta Orthop Scand. 61(2):136-9, 1990
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