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Ankle Fracture

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(Redirected from Bimalleolar Fracture)

Other Names

  • Ankle Subluxation
  • Dislocated Ankle
  • Subluxed Ankle
  • Dislocated Ankle
  • Trimal fracture
  • Bimal fracture
  • Distal fibular fracture
  • Bimalleolar and bimalleolar-equivalent fractures
  • Posterior malleolus fractures
  • Bosworth fracture-dislocations
  • Open ankle fractures

Background

  • This page describes fractures, subluxations and dislocations of the Ankle Joint

History

  • The first detailed description of a specific ankle fracture mechanism is generally credited to Percivall Pott in 1768[1]

Epidemiology

  • Ankle Fracture
    • More than 250,000 annually in the United States[2]
  • Ankle Fracture-Dislocations
    • Tibiotalar dislocations may occur in 21-36% of ankle fractures[3]
    • Occurs more in males (72%) than female[4]
  • Isolated Dislocations
    • Isolated dislocations without concomitant fracture are rare but do happen[5]
    • Estimated incidence of pure ankle dislocation is 0.065% (13/20,000) in patients presenting with an ankle injury[4]

Introduction

Lateral ankle XR of open fibular fracture and tibiotalar dislocation
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Ankle Fracture Case
Bimalleolar Ankle Fracture Anterior-posterior (AP) view (left) of the ankle demonstrates fracture of the fibula visualized as cortical disruption along the lateral border and a subtle distal tibia fracture seen approximately 2 mm above the distal tip, with preservation of the posterior border of the tibia (seen on lateral view [right]). In addition, the AP view reveals widening of the medial aspect of the superior talar joint space compared with the lateral space, suggesting talar tilt. This pattern of distal fibula fracture with medial malleolus involvement is often due to supination-external rotation injury and is likely associated with significant joint instability if the deltoid ligament is disrupted.¹ A small avulsion of the talar neck is also seen along the medial border, opposite the site of the distal tibia fracture.[6]
The CT reconstructions and radiographs of ankle fracture-dislocations with four different injury mechanisms according to the Lauge-Hansen's classification. (A) Supination-adduction; (B) Supination-external rotation; (C) Pronation abduction; (D) Pronation-external rotation.[7]

General

  • Ankle fractures are characterized by a break of one or more bones forming the ankle joint
  • Most commonly involves the distal fibula or tibia
  • Usually caused by twisting injuries, falls, or trauma
  • Symptoms include pain, swelling, bruising, and difficulty walking
  • Diagnosis is made radiographically
  • Treatment ranges from bracing or casting to surgical fixation

Terminology

  • General
    • Ankle fracture refers to fracture of the bones which make up the ankle (talus, tibia, fibula)
    • Dislocation refers to loss of congruence of the joint usually associated with fractures
  • Unimalleolar fracture
  • Bimalleolar fracture
    • Fracture of two malleoli (most commonly lateral and medial)
    • 23% of ankle fractures
  • Trimalleolar fracture
    • fracture of all three malleoli (lateral, medial, and posterior)
    • 7% of ankle fractures
  • Isolate talus are discussed separately

Ankle Fracture Dislocation

  • More common than isolated dislocations (meaning no associated fractures)
  • Occurs due to abduction force causing displacement of the talus and malleolar fracture[8]

Isolated Dislocation

  • Posteromedial Dislocation
    • caused by maximal plantarflexion, axial load, and inversion of the ankle[9]
    • Often leads to open dislocation
  • Anterior Dislocation[4]
    • Occurs after maximum plantar flexion and ankle inversion allowing anterior movement of the talus
    • May lead to rupture of the anterolateral capsule, anterior talofibular ligament (ATFL), calcaneofibular ligament (CFL), and extensor and peroneal retinaculi
  • Superior Dislocation[4]
    • Forced dorsiflexion and ankle eversion may cause rupture of the tibiofibular syndesmosis and superior movement of the ankle joint

Mechanism of Injury

  • General
    • Most often occur by rotational mechanisms with the external forces transmitted through the foot via the talus to the malleoli
    • Lauge-Hansen ankle fracture classification (see below) attempts to describe injury based on position of foot at time of injury
  • Fracture-dislocations
    • A 2017 systemic review of pure dislocations showed that sporting injuries (31%) and motor vehicle accidents (30%) are the most common causes[4]

Associated Conditions

Anatomy of the Ankle Joint

Risk Factors

  • Medial malleolus hypoplasia
  • Ligamentous laxity
  • Weak peroneal muscles
  • History of ankle sprains
  • Previous ligamentous injury

Differential Diagnosis

Differential Diagnosis Ankle Pain

Clinical Features

Typical appearance of an ankle fracture

History

  • Mechanism is helpful to identify potential injury patterns[10]
    • The most common causes are twisting/rotational injuries and falls
    • Followed by sports, injuries
  • Patients endorse pain, swelling, inability to ambulate
  • Patient may describe deformity
  • Typically unable to bear weight immediately following the injury
  • Sense of instability or "giving way".

Physical Exam: Physical Exam Foot and Ankle

  • Inspection: assess for swelling, ecchymosis, and deformity
    • Skin tenting, break in skin may be present
    • Deformity is often obvious
  • Bony landmarks follow the Ottawa Ankle Rules
    • Fibula, the medial and lateral malleoli, base of the fifth metatarsal, navicular, and proximal fibula
  • Range of motion is almost universally limited
  • Plantar and dorsiflexion may be intact or too painful to assess
  • Careful, thorough neurovascular examination
  • Evaluate for antalgic gait or complete inability to bear weight

Special Tests

  • Currently, there are no validated special tests for ankle fractures

Evaluation

  • Weber C fracture with widening of joint space on stress view (note hand at bottom of XR)
    Weber C fracture with widening of joint space on stress view (note hand at bottom of XR)
  • Bimal equivalent on mortise view. Note the small avulsion fracture on the tip of the medial malleolus suggesting medial instability.
    Bimal equivalent on mortise view. Note the small avulsion fracture on the tip of the medial malleolus suggesting medial instability.
  • Lateral XR showing trimalleolar fracture with posterior dislocation of the talus relative to the tibia.
    Lateral XR showing trimalleolar fracture with posterior dislocation of the talus relative to the tibia.
  • Ankle XR mortis view showing trimalleolar fracture with unstable joint.
    Ankle XR mortis view showing trimalleolar fracture with unstable joint.

Radiographs

  • Standard Radiographs Ankle
    • Includes AP, lateral and mortise views
  • Pre-reduction radiographs
    • Important to rule out trauma mimicking ankle fracture dislocations (i.e. distal tibia fracture, subtalar dislocation)
    • However, do not delay reduction attempt if concern about compromised soft tissue
  • Post-reduction radiographs
    • Should be obtained
    • Useful for: adequacy of reduction, surgical planning and decision making
  • Do not provide adequate assessment of
    • Articular injury
    • Posterior malleolar involvement
    • Osteochondral Lesion size
    • Intra-articular loose bodies
    • Inadequate or malreduction
  • Findings

CT

  • Indications
    • Generally surgeon dependent and topic for research
  • Leung et al found preoperative CT allowed for detection of[11]
    • Posterior malleolar lesions
    • Intra-articular loose bodies
    • Bony avulsions
  • Operative planning
    • Black et al found ankle-fracture dislocations were more likely to be changed than fractures (31% vs 20%)[12]
    • Operative plans are altered in about 25% of ankle fractures due to additional findings on CT[11]

MRI

  • Not routinely required
  • Can be used to help characterize soft tissue injuries

Classification

Danis-Weber Classification
Decision making tree for ankle fractures proposed by Michelson and simplified by Ovaska[13]

Lauge-Hansen Ankle Fracture Classification

  • General
    • Developed in 1948 from cadaveric research looking at fracture patterns, foot position and direction of force[14]
    • Widely used but does not predict all ankle-fracture patterns
  • Supination /Adduction (SAD)
    • Talofibular sprain or distal fibular avulsion
    • Vertical medial malleolus and impaction of anteromedial distal tibia
  • Supination /External Rotation (SER)
    • Anterior tibiofibular ligament sprain
    • Lateral short oblique fibula fracture (anteroinferior to posterosuperior)
    • Posterior tibiofibular ligament rupture or avulsion of posterior malleolus
    • Medial malleolus transverse fracture or disruption of deltoid ligament
  • Pronation /Abduction (PAB)
    • Medial malleolus transverse fracture or disruption of deltoid ligament
    • Anterior tibiofibular ligament sprain
    • Transverse comminuted fracture of the fibula above the level of the syndesmosis
  • Pronation /External Rotation (PER)
    • Medial malleolus transverse fracture or disruption of deltoid ligament
    • Anterior tibiofibular ligament disruption
    • Lateral short oblique or spiral fracture of fibula (anterosuperior to posteroinferior) above the level of the joint
    • Posterior tibiofibular ligament rupture or avulsion of posterior malleolus

Danis Weber Classification

  • General
    • First presented by Danis in 1949, then popularized by Weber[15]
    • Classifies ankle fractures into 3 groups based on the level of lateral malleolus fracture seen on radiographs
    • Does not address medial and posterior injury patterns, not specific to ankle fracture-dislocations
    • Commonly referred to as the 'Weber classification'
  • Weber A
    • Infrasyndesmotic, stable
  • Weber B
    • Transsyndesmotic, can be stable or unstable
  • Weber C
    • Suprasyndesmotic, unstable

AO/OTA Classification System

  • 44A: infrasyndesmotic
  • 44B: transsyndesmotic
  • 44C: suprasyndesmotic

Management

Post-reduction and splinting radiograph of trimalleolar fracture
Fluoroscopy status post ORIF of trimalleolar fracture

Acute

  • Follow ATLS algorithm when indicated
    • Mechanism of injury will help suggest need for broader evaluation
  • Closed Reduction Ankle
    • Obvious fracture-dislocations should be reduced
    • Most commonly performed in Emergency department
    • Typically requires procedural sedation, intra-articular block
    • Placed in Posterior Short Leg Splint with Stirrup
    • Procedure is usually successful, however soft tissue can block closed reduction[16]

Nonoperative

Operative

  • Indications
    • Talar displacement
    • Bimalleolar fracture
    • Bimalleolar-equivalent fracture
    • Posterior malleolar fracture (> 25% or > 2mm step-off)
    • Bosworth fracture-dislocations
    • Open fractures
    • Nonunion
  • Technique
    • Open reduction, internal fixation
    • Role of external fixation is not well defined

Rehab and Return to Play

Early Rehab exercises
Intermediate rehab program
Advanced rehabilitation program

Ankle Fracture Rehab Protocol PDFs

Phase 1: Acute/Protective Phase (Weeks 0–2)[17]

  • Immobilization in a posterior splint, cast, or walking boot per surgeon preference
  • Elevation of the ankle above heart level to reduce swelling
  • Non-weight-bearing with crutches or assistive device (standard initial period in most protocols)
  • Cryotherapy and edema management
  • Exercises
    • Gentle active toe range of motion (ROM)
    • Isometric contractions of surrounding musculature as tolerated
  • DVT prophylaxis per institutional protocol

Phase 2: Early Mobilization (Weeks 2–6)

  • Early weight-bearing (as early as 2 weeks post-ORIF) in a walking boot is supported by recent trials[18]
    • Demonstrating non-inferior or superior functional outcomes
    • Similar complication rates compared with 6 weeks of non-weight-bearing
  • Transition to a removable ankle support (boot/brace) to allow gentle ankle mobilization[19]
    • Removable supports may provide better function than non-removable casts
  • Exercises/ Therapy
    • Begin passive and active ankle ROM exercises: dorsiflexion, plantarflexion, inversion, eversion
    • Ankle alphabet exercises and towel stretches
    • Scar mobilization (if surgical)
    • Gait training with progressive weight-bearing as tolerated

Phase 3: Progressive Strengthening (Weeks 6–8)

  • Progression to full weight-bearing and restoration of normal gait mechanics
  • Exercises/Therapy[20]
    • Full active and passive ROM in all planes
    • Isometric progressing to isotonic ankle strengthening (theraband resistance exercises in all planes)
    • Proprioception training: single-leg stance, wobble board, balance pad
    • Stationary cycling and pool-based exercises for cardiovascular conditioning
    • Gait normalization without assistive devices

Phase 4: Advanced Strengthening and Functional Training (Weeks 8–12)

  • Advanced ankle and intrinsic foot strengthening[21]
  • Pool running progressing to dry-land running (linear)
  • Progressive balance challenges: single-leg stance on unstable surfaces, Y-Balance Test training
  • Lateral and rotational functional movements
  • Incorporation of mobilization and balance exercises into the program
  • which has been shown to significantly improve pain, ROM, quality of life, and peak muscle torque
  • Stair climbing, step-ups, and eccentric calf strengthening

Phase 5: Sport-Specific Training and Return to Play (Weeks 12+)

  • Sport-specific agility drills: cutting, pivoting, jumping, landing
  • Plyometric training with progressive intensity
  • Full-speed running with directional changes
  • Sport-specific skill work (e.g., kicking, sprinting, court/field drills)
  • Gradual return to practice, then full competition

Return-to-Play Criteria

  • Radiographic evidence of fracture union[22]
  • Full, pain-free ROM (particularly dorsiflexion, compared to contralateral side)
  • Strength ≥90% of contralateral limb (isokinetic or manual testing)
  • Functional testing benchmarks:
    • Dorsiflexion lunge test (symmetry with contralateral side)
    • Star Excursion / Y-Balance Test (anterior reach within 3.3% of uninjured leg)
    • Agility T-test
    • Single-leg hop test / vertical jump test
  • No pain or swelling with sport-specific activities
  • Psychological readiness for return to competition

Expected Return-to-Sport Timelines

  • Nonoperatively managed (stable/undisplaced)[23]
    • mean ~20 weeks (range 4–52 weeks)
    • 100% return-to-sport rate
  • Operatively managed
    • Mean ~35 weeks (range 8–104 weeks)
    • 87% return-to-sport rate
  • Conservative management of stable fractures may allow a quicker return to sport with lower rates of persisting symptoms (17% vs. 71%)

Prognosis and Complications

Unstable weber B 6 weeks out from injury in a noncompliant patient. Note the significant callous formation.

Prognosis

  • Fracture-dislocations
    • Higher revision (ORIF) rate than nondislocated ankle fractures[24]
    • 82% of patients reported excellent or good outcomes with a mean follow up of 2-6 years[25]
    • More likely to have worse Foot and Ankle Outcome Score (FAOS) compared to non-dislocated fractures[26]
  • Postoperative
    • Patients tend to demonstrate significant improvement in function from 6 months to 1 year following surgery[27]
  • Early reduction helps with[28]
    • Reduced risk of neurovascular and skin complications
    • Releases soft-tissue tension
    • Reduce the time of cartilaginous impingement
    • Prevent or delay to surgery if indicated
  • Factors that may lead to worse outcomes[4]
    • Advanced age
    • Involvement of vascular injury
    • Delay timing for reduction
    • Inferior tibiofibular ligament injury

Acute complications

  • Soft tissue complications
    • Wound dehiscence, skin necrosis and infection are most common complications[29]
    • Increased soft-tissue injury increases risk of postoperative complications when not properly addressed
    • 3 fold increased risk when dislocation is present[30]
    • Delays in treatment of fracture-reduction increases risk of soft tissue complications
  • Malunion or nonunion during reduction
  • Open Fracture
    • Up to 1/3 of fracture-dislocations are open[31]
    • Higher reported incidence of open dislocation when fracture is absent
  • Osteochondral Lesion (OCL)
    • Present in up to 79% of all ankle fractures[32]
    • Risk increases with severity of of injury, notably in fracture-dislocations
    • Odds Ratio of 5.56 for dislocated vs non-dislocated fractures for developing OCL[33]
  • Intra-articular loose bodies
  • Articular Malreduction
    • Major predictive factor affecting outcomes
    • Associated with fracture comminution, poor bone quality, technical errors[34]
    • Higher risk in dislocated vs non-dislocated ankle fractures[35]
  • Posterior malleolar involvement
    • More common in dislocated vs non-dislocated fractures[35]

Late Complications

  • Post Traumatic Ankle Osteoarthritis[36] (PTOA)
    • One study found 14% of patients had PTOA[25]
    • Another study showed up to 63% of patients with ankle fracture-dislocations[37]
  • Stiffness
  • Degenerative changes
  • Joint instability
  • Capsular calcification
  • Chronic pain

See Also

Internal

External

References

  1. ↑ Pott P. Some Few General Remarks on Fractures and Dislocations. London: Hawes, Clarke, and Collins; 1768.
  2. ↑ Barrett, JA, Baron, JA, Karagas, MR, Beach, ML. Fracture risk in the U.S. medicare population. J Clin Epidemiol. 1999;52(3):243–249.
  3. ↑ Regier M, Petersen JP, Hamurcu A, Vettorazzi E, Behzadi C, Hoffmann M, Großterlinden LG, Fensky F, Klatte TO, Weiser L, Rueger JM, Spiro AS. High incidence of osteochondral lesions after open reduction and internal fixation of displaced ankle fractures: Medium-term follow-up of 100 cases. Injury. 2016 Mar;47(3):757-61.
  4. ↑ 4.0 4.1 4.2 4.3 4.4 4.5 Wight L, Owen D, Goldbloom D, Knupp M. Pure Ankle Dislocation: A systematic review of the literature and estimation of incidence. Injury. 2017 Oct;48(10):2027-2034.
  5. ↑ Fernandes, T . Mechanism of talo-tibial dislocation without fracture. J Bone Joint Br. 1976;58(B):364–365.
  6. ↑ Bhat, Sundeep R., and Gus M. Garmel. "Image Diagnosis: Ankle Fractures and Dislocations." The Permanente Journal 14.2 (2010): 54.
  7. ↑ Cao, Mu-Min, et al. "A systematic review of ankle fracture-dislocations: Recent update and future prospects." Frontiers in Surgery 9 (2022): 965814.
  8. ↑ LAUGE N. Fractures of the ankle; analytic historic survey as the basis of new experimental, roentgenologic and clinical investigations. Arch Surg. 1948 Mar;56(3):259-317. PMID: 18874737.
  9. ↑ Lamraski, G, Clegg, E. Unusual upward closed tibiotalar dislocation without fracture: a case report. Foot Ankle Surg. 2010;16(2):e44–e46.
  10. ↑ Lin, Chung‐Wei Christine, et al. "Rehabilitation for ankle fractures in adults." Cochrane database of systematic reviews 11 (2012).
  11. ↑ 11.0 11.1 Leung, KH, Fang, CX, Lau, TW, Leung, FK. Preoperative radiography versus computed tomography for surgical planning for ankle fractures. J Orthop Surg (Hong Kong). 2016;24(2):158–162.
  12. ↑ Black, EM, Antoci, V, Lee, JT. Role of preoperative computed tomography scans in operative planning for malleolar ankle fractures. Foot Ankle Int. 2013;34(5):697–704.
  13. ↑ Ovaska, Mikko. "Complications in ankle fracture surgery." Acta Orthopaedica 86.sup358 (2015): 1-35.
  14. ↑ Lauge, N . Fractures of the ankle; analytic historic survey as the basis of new experimental, roentgenologic and clinical investigations. Arch Surg. 1948;56(3):259–317.
  15. ↑ Danis, R . Les fractures malleolaires: théorie et pratique de l’osteosynthese [Malleolar fractures: Theory and practice of osteosynthesis.]. Paris, France: Masson; 1949.
  16. ↑ 14. Ermis, MN, Yagmurlu, MF, Kilinc, AS, Karakas, ES. Irreducible fracture dislocation of the ankle caused by tibialis posterior tendon interposition. J Foot Ankle Surg. 2010;49:166–171
  17. ↑ Bretherton, Christopher Patrick, et al. "Early versus delayed weight-bearing following operatively treated ankle fracture (WAX): a non-inferiority, multicentre, randomised controlled trial." The Lancet 403.10446 (2024): 2787-2797.
  18. ↑ Khojaly, Ramy, et al. "Immediate weight-bearing compared with non-weight-bearing after operative ankle fracture fixation: results of the INWN pragmatic, randomized, multicenter trial." JBJS 107.13 (2025): 1423-1438.
  19. ↑ Lin, Chung‐Wei Christine, et al. "Rehabilitation for ankle fractures in adults." Cochrane database of systematic reviews 11 (2012).
  20. ↑ Moseley, Anne M., et al. "Rehabilitation after immobilization for ankle fracture: the EXACT randomized clinical trial." Jama 314.13 (2015): 1376-1385.
  21. ↑ Salas-Gomez, Diana, et al. "Quantifying balance deficit in people with ankle fracture six months after surgical intervention through the Y-Balance test." Gait & Posture 95 (2022): 249-255.
  22. ↑ Clanton, Thomas O., et al. "Return to play in athletes following ankle injuries." Sports Health 4.6 (2012): 471-474.
  23. ↑ Robertson, Greg AJ, et al. "Epidemiology, management, and outcome of sport-related ankle fractures in a standard UK population." Foot & ankle international 35.11 (2014): 1143-1152.
  24. ↑ Pincus, D, Veljkovic, A, Zochowski, T, Mahomed, N, Ogilivie-Harris, D, Wasserstein, D. Rate and risk factors for intermediate-term reoperation after ankle fracture fixation: a population-based cohort study. J Orthop Trauma. 2017;31:e315–e320.
  25. ↑ 25.0 25.1 Lindsjo, U . Operative treatment of ankle fracture-dislocations: a follow-up study of 306/321 consecutive cases. Clin Orthop Relat Res. 1985(199):28–38.
  26. ↑ Sculco, PK, Lazaro, LE, Little, MM. Dislocation is a risk factor for poor outcome after supination external rotation type ankle fractures. Arch Orthop Trauma Surg. 2016;136(1):9–15.
  27. ↑ Nilsson, G, Jonsson, K, Ekdahl, C, Eneroth, M. (2007) Outcome and quality of life after surgically treated ankle fractures in patients 65 years or older. BMC Musculoskelet Disord. 8:127
  28. ↑ Payne, R, Kinmont, JC, Moalypour, SM. Initial management of closed fracture-dislocations of the ankle. Ann R Coll Surg Engl. 2004;86(3):177–181.
  29. ↑ Stufkens, SA, Knupp, M, Horisberger, M, Lampert, C, Hintermann, B. Cartilage lesions and the development of osteoarthritis after internal fixation of ankle fractures: a prospective study. J Bone Joint Surg Am. 2010;92(2):279–286.
  30. ↑ Kelly, PJ, Peterson, LF, Compound dislocation of the ankle without fracture. Am J Surg. 1962;103(2):170–172.
  31. ↑ Kelly, PJ, Peterson, LF, Compound dislocation of the ankle without fracture. Am J Surg. 1962;103(2):170–172.
  32. ↑ O’Loughlin, PF, Heyworth, BE, Kennedy, JG. Current concepts in the diagnosis and treatment of osteochondral lesions of the ankle. Am J Sports Med. 2010;38(2):392–404.
  33. ↑ Regier, M, Petersen, JP, Hamurcu, A. High incidence of osteochondral lesions after open reduction and internal fixation of displaced ankle fractures: medium-term follow-up of 100 cases. Injury. 2016;47(3):757–761.
  34. ↑ Berkes, MB, Little, MT, Lazaro, LE. Articular congruity is associated with short-term clinical outcomes of operatively treated SER IV ankle fractures. J Bone Joint Surg Am. 2013;95(19):1769–1775.
  35. ↑ 35.0 35.1 Warner, SJ, Schottel, PC, Hinds, RM, Helfet, DL, Lorich, DG. Fracture-dislocations demonstrate poorer postoperative functional outcomes among pronation external rotation IV ankle fractures. Foot Ankle Int. 2015;36(6):641–647.
  36. ↑ Wang YT, Wu XT, Chen H. Pure closed posteromedial dislocation of the tibiotalar joint without fracture. Orthop Surg. 2013 Aug;5(3):214-8
  37. ↑ Regan, DK, Gould, S, Manoli, A III, Egol, KA. Outcomes over a decade after surgery for unstable ankle fracture: functional recovery seen 1 year postoperatively does not decay with time. J Orthop Trauma. 2016;30(7):e236–e241
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