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Myerson Lisfranc

Original Myerson-modified Hardcastle classification of Lisfranc fracture-dislocations

Per-foot morphology classification of displaced tarsometatarsal fracture-dislocations into total incongruity, medial or lateral partial incongruity, and partial or total divergence. The original five-pattern system communicates displacement topology but does not encode subtle-injury stability, ligament integrity, treatment indication or prognosis by itself.

vigenteMyerson, Fisher, Burgess and KenzoraOriginal 1986 five-pattern A-C system; later type D kept separate1986XR, CT
Fonte primária5 categorias
AType A, total incongruityB1Type B1, medial partial incongruityB2Type B2, lateral partial incongruityC1Type C1, partial divergenceC2Type C2, total divergence

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Categorias

Reescritas a partir da fonte e citadas
A
1 de 5

Type A, total incongruity

Total incongruity: the bases of all five metatarsals are displaced together in the same direction, classically homolateral lateral displacement but potentially dorsoplantar displacement. This is a displacement pattern of the entire tarsometatarsal complex, not merely widening of the Lisfranc interval.

CondutaObtain urgent foot-and-ankle specialist assessment and separately report reduction status, soft-tissue condition, fractures, comminution, neurovascular findings and physiologic stability. A displaced total-incongruity injury commonly requires reduction and stabilization, but the A label alone does not select fixation versus fusion or dictate timing; threatened skin, open injury, compartment syndrome or neurovascular compromise drives urgent action independently.
RiscoThe pattern represents extensive tarsometatarsal incongruity, but no validated contemporary probability of arthritis, fusion, reoperation or functional loss belongs to type A alone. In the historical 1986 cohort, reduction quality and late instability or degeneration were major outcome determinants across types; those center-era results cannot be converted into an individual type-A forecast.
verificadoFracture dislocations of the tarsometatarsal joints: end results correlated with pathology and treatmentMyerson et al. 1986, DOI 10.1177/107110078600600504, primary A-C classification and outcome discussion; Siddiqui et al. 2014, DOI 10.1148/rg.342125215, Myerson Table 2 and total-incongruity description; current ACR Acute Trauma to the Foot for imaging escalation.
B1
2 de 5

Type B1, medial partial incongruity

Partial or isolated incongruity with medial displacement of the first metatarsal base at the first tarsometatarsal joint, while the lateral four metatarsal bases are not part of a divergent displacement pattern. Confirm the first-ray direction across adequate projections rather than inferring B1 from an isolated fracture.

CondutaDescribe first-ray displacement, articular injury, reducibility, ligamentous and bony components and any instability under load when that can be assessed safely. Specialist management depends on true displacement or instability, cartilage injury, soft tissue and patient context. The morphology code supports planning but does not autonomously mandate one operation, and a reduced injury can remain unstable despite losing the original B1 appearance.
RiscoB1 has no portable per-type risk percentage. A partial pattern can be clinically consequential despite involving fewer rays, and missed or inadequately reduced instability can lead to painful post-traumatic degeneration. Prognosis depends more directly on recognition, anatomic alignment, ligament and cartilage injury, energy, treatment and follow-up than on the B1 token by itself.
verificadoFracture dislocations of the tarsometatarsal joints: end results correlated with pathology and treatmentMyerson et al. 1986, primary partial-incongruity framework; Siddiqui et al. 2014, Myerson Table 2, isolated first-tarsometatarsal displacement; Mahmoud et al. 2015 and Engelmann et al. 2023 for limits of observer reliability and applicability.
B2
3 de 5

Type B2, lateral partial incongruity

Partial or isolated incongruity with lateral displacement of one or more of the lateral four metatarsal bases, M2 through M5, without medial displacement of M1 creating divergence. State which rays and tarsometatarsal joints are involved because the same B2 code can represent different anatomic extents.

CondutaReport the involved lateral rays, occult fractures or comminution on CT when relevant, and assess first-ray position carefully because uncertain medial M1 displacement creates the B2-versus-C1 boundary. Management is based on displacement and instability, bony versus ligamentous anatomy, reducibility and patient factors; do not turn B2 into a universal procedure or infer stability from nonweightbearing alignment alone.
RiscoB2 can be subtle and therefore vulnerable to delayed recognition, but the classification supplies no validated B2-specific probability of poor outcome. Later series have not produced a universally transportable per-type prognosis. Preserve detection confidence, alignment, instability, cartilage injury and treatment quality rather than telling an agent that B2 is intrinsically the best or worst outcome group.
verificadoFracture dislocations of the tarsometatarsal joints: end results correlated with pathology and treatmentMyerson et al. 1986, primary partial-incongruity classification; Siddiqui et al. 2014, Myerson Table 2 and discussion of lesser-metatarsal displacement; ACR Acute Trauma to the Foot Variant 5 for CT or MRI when radiographs are normal or equivocal.
C1
4 de 5

Type C1, partial divergence

Partial divergent incongruity: M1 is displaced medially while fewer than all four lateral metatarsal bases are displaced laterally. The divergence direction and the count of affected lateral rays distinguish C1 from B2 and C2; when M1 direction or the full lateral column is not evaluable, retain that boundary uncertainty.

CondutaDivergence generally warrants prompt specialist review, careful soft-tissue assessment and anatomic characterization for reduction and stabilization planning. The code does not select a specific operation. CT can map fractures and comminution, while weightbearing evaluation or MRI may be needed for a separate stability or ligament question when safe and clinically appropriate.
RiscoC1 communicates a divergent injury but is not a calibrated risk stratum. Extent of joint involvement, high-energy or crush mechanism, articular damage, persistent instability, reduction quality and complications dominate outcome. Historical aggregate outcomes from displaced injuries and modern reliability studies must not be represented as a C1-specific probability.
verificadoFracture dislocations of the tarsometatarsal joints: end results correlated with pathology and treatmentMyerson et al. 1986, primary divergent subdivision; Siddiqui et al. 2014, Myerson Table 2, M1 medial with partial lateral-ray divergence; Mahmoud et al. 2015 and Engelmann et al. 2023 for reliability context.
C2
5 de 5

Type C2, total divergence

Total divergent incongruity: M1 is displaced medially and all four lateral metatarsal bases, M2 through M5, are displaced laterally. This differs from type A because the rays diverge rather than moving together in one homolateral direction.

CondutaProvide urgent specialist assessment, describe full-column displacement, fractures, articular comminution, soft-tissue threat, reduction status and associated injuries, and act immediately on open injury, neurovascular compromise or compartment syndrome. Extensive divergence often requires operative restoration of alignment, but C2 alone does not determine fixation method, fusion, timing or prognosis.
RiscoC2 denotes extensive divergent incongruity and plausibly high anatomic burden, yet the system contains no validated C2-specific rate of amputation, arthritis, fusion or disability. In the original high-energy cohort, direct crush injury and inadequate alignment were adverse across the series. Mechanism, soft tissue, cartilage, reduction and rehabilitation must remain explicit risk inputs.
verificadoFracture dislocations of the tarsometatarsal joints: end results correlated with pathology and treatmentMyerson et al. 1986, primary C2 definition and historical pathology, treatment and outcome correlations; Siddiqui et al. 2014, Myerson Table 2, complete divergent pattern; current ACR imaging pathway for unresolved or occult injury.
Lógica de decisão estruturada

Use the original five A-C patterns only, pair every code with anatomy, and keep subtle-injury stability, later type D, prognosis and treatment as separate layers.

{
  "categories": [
    {
      "outcome_code": "A",
      "congruity": "total_incongruity",
      "displaced_metatarsals": "M1_through_M5",
      "direction": "same_direction_homolateral_lateral_or_dorsoplantar"
    },
    {
      "outcome_code": "B1",
      "congruity": "partial_isolated_incongruity",
      "displaced_metatarsals": "M1",
      "direction": "medial"
    },
    {
      "outcome_code": "B2",
      "congruity": "partial_isolated_incongruity",
      "displaced_metatarsals": "one_or_more_of_M2_through_M5",
      "direction": "lateral"
    },
    {
      "outcome_code": "C1",
      "congruity": "partial_divergent_incongruity",
      "displaced_metatarsals": "M1_medial_plus_fewer_than_all_four_lateral_metatarsals",
      "direction": "divergent"
    },
    {
      "outcome_code": "C2",
      "congruity": "total_divergent_incongruity",
      "displaced_metatarsals": "M1_medial_plus_all_M2_through_M5_lateral",
      "direction": "divergent"
    }
  ],
  "applicability": {
    "use_for": "Morphologic communication of an acute Lisfranc tarsometatarsal fracture-dislocation with visible incongruity or displacement.",
    "classification_unit": "one_injured_foot",
    "required_inputs": [
      "side",
      "M1_through_M5_alignment",
      "direction_of_each_displaced_metatarsal_base",
      "extent_of_tarsometatarsal_incongruity",
      "weightbearing_status",
      "radiograph_or_CT_adequacy"
    ],
    "outside_scope": [
      "occult_or_subtle_stability_determination",
      "ligament_integrity",
      "Nunley_Vertullo_athletic_staging",
      "2015_type_D_subtyping",
      "operative_indication",
      "patient_specific_prognosis"
    ]
  },
  "classification_algorithm": [
    {
      "step": 1,
      "question": "Are all five metatarsal bases displaced together in the same direction?",
      "yes": "A",
      "no": "continue"
    },
    {
      "step": 2,
      "question": "Is only the first ray displaced medially while the lateral rays remain congruent?",
      "yes": "B1",
      "no": "continue"
    },
    {
      "step": 3,
      "question": "Are one or more lateral four metatarsal bases displaced laterally without medial M1 divergence?",
      "yes": "B2",
      "no": "continue"
    },
    {
      "step": 4,
      "question": "Is M1 displaced medially while lateral rays displace laterally?",
      "yes": "C_branch",
      "no": "out_of_schema_or_unresolved"
    },
    {
      "step": 5,
      "question": "In a divergent injury, are all four lateral metatarsals displaced?",
      "yes": "C2",
      "no": "C1"
    }
  ],
  "imaging_and_quality_gate": {
    "initial_assessment": "Use a complete foot radiographic series; when safe and feasible, bilateral weightbearing views improve assessment of subtle alignment and physiologic instability.",
    "CT_role": "CT defines occult fractures, articular comminution and three-dimensional displacement and is useful for operative planning, but a nonweightbearing CT does not by itself prove physiologic stability.",
    "MRI_role": "MRI can assess the Lisfranc ligament complex when radiographs or CT do not resolve a suspected ligamentous injury; ligament status is an additional variable, not an A-C code.",
    "current_ACR_next_test": "When acute Lisfranc injury remains suspected and radiographs are normal or equivocal, current ACR guidance rates CT without contrast or MRI without contrast as usually appropriate alternatives.",
    "adequacy_rule": "If the full first-through-fifth tarsometatarsal complex or displacement direction cannot be followed, return unclassifiable or the competing patterns rather than assigning from one projection."
  },
  "stability_and_variant_boundaries": {
    "morphology_not_stability": "The original A-C pattern describes displacement topology. It does not encode whether a subtle or reduced injury is stable under load.",
    "type_D_2018_extension": "Sivakumar and colleagues' 2018 topical review proposed D1 for a stable or nondisplaced injury with C1-M2 distance at most 2 mm and D2 for an unstable or displaced injury over 2 mm, with D2L ligamentous and D2B bony subtypes.",
    "noninterchangeability": "Type D is not part of the original five-code 1986 output. Do not silently append D1 or D2, or use its 2 mm stability boundary to redefine A, B or C.",
    "Nunley_Vertullo": "The Nunley-Vertullo system stages subtle athletic Lisfranc injury using clinical and weightbearing or stress information; it answers a different question and cannot be converted one-to-one to Myerson A-C.",
    "reduced_injury": "A previously reduced or spontaneously aligned injury may be clinically unstable yet out of schema for the original displaced-pattern classification."
  },
  "reporting_contract": {
    "required_output": "Report side, Myerson code and plain-language displacement pattern, then separately describe fractures, columns or joints involved, comminution, instability evidence, ligament injury and associated midfoot injury.",
    "no_code_only": "Because observer performance and applicability vary by image set and injury spectrum, never return the code without its anatomic descriptor.",
    "uncertainty": "If B2 versus C1 depends on uncertain M1 medial displacement, report that exact boundary and request a better aligned or weightbearing examination when clinically safe."
  },
  "management_boundary": {
    "historical_context": "In the original displaced-injury series, restoration and maintenance of anatomic alignment were central, and reduction quality strongly related to outcome; historical thresholds and operations are not a universal current per-code prescription.",
    "current_decision_inputs": "Treatment depends on displacement and instability, bony versus ligamentous anatomy, soft-tissue condition, reducibility, articular damage, patient factors, timing and specialist assessment.",
    "nonoperative_guard": "Do not infer that every B or C pattern mandates the same operation, and do not infer that a normal-appearing nonweightbearing study is safe for unrestricted loading.",
    "urgent_context": "Open injury, threatened skin, neurovascular compromise, compartment syndrome or irreducible dislocation requires urgent clinical action independent of the Myerson label."
  },
  "risk_and_reliability": {
    "original_cohort": "The 1986 historical cohort included 72 patients with 76 injuries; among the long-term analyzed feet, only 49 percent had excellent or good results, direct crush did poorly, reduction quality was a major determinant, and late instability or degeneration drove symptoms. These results are not calibrated per-type probabilities for contemporary care.",
    "reliability_2015": "After observer training on 39 radiographs, mean intraobserver ICC was 0.94 and interobserver ICC 0.81, supporting reproducibility in that study.",
    "reliability_2023": "A later 31-case radiograph-plus-CT study reported Myerson interobserver ICC 0.277 and intraobserver ICC 0.505, and many cases were considered non-applicable; differences in cohort, images and methods explain why reliability must not be advertised as universal.",
    "prognosis_guard": "Code alone does not predict post-traumatic arthritis, need for fusion, return to sport or patient-reported outcome; alignment, ligamentous damage, energy, cartilage injury and treatment quality materially affect prognosis."
  },
  "missing_input_behavior": [
    "If weightbearing or stress stability is unknown in a subtle injury, return stability unknown and do not force an A-C type.",
    "If M1 direction is not visible, do not distinguish B2 from C1 by guessing.",
    "If not all lateral rays are evaluable, do not distinguish C1 from C2.",
    "If the injury has been reduced before imaging, state that the original displacement pattern may be unrecoverable.",
    "If the requested code includes D1, D2, D2L or D2B, identify it as the later extension and do not claim it came from the 1986 five-pattern system."
  ],
  "supporting_sources": [
    {
      "role": "primary_classification_and_outcomes",
      "citation": "Myerson et al. Foot & Ankle. 1986;6:225-242",
      "doi": "10.1177/107110078600600504",
      "pmid": "3710321"
    },
    {
      "role": "later_type_D_extension",
      "citation": "Sivakumar et al. Orthopedics. 2018;41:e168-e175",
      "doi": "10.3928/01477447-20180213-07",
      "pmid": "29451936"
    },
    {
      "role": "imaging_application",
      "citation": "Siddiqui et al. RadioGraphics. 2014;34:514-531",
      "doi": "10.1148/rg.342125215"
    },
    {
      "role": "reliability_study",
      "citation": "Mahmoud et al. International Orthopaedics. 2015;39:2215-2218",
      "doi": "10.1007/s00264-015-2939-8",
      "pmid": "26224617"
    },
    {
      "role": "reliability_and_applicability_study",
      "citation": "Engelmann et al. Fuss und Sprunggelenk. 2023;21:333-340",
      "doi": "10.1016/j.fuspru.2023.07.007"
    },
    {
      "role": "current_imaging_guidance",
      "citation": "ACR Appropriateness Criteria Acute Trauma to the Foot",
      "doi": "10.1016/j.jacr.2020.01.019",
      "pmid": "32370964"
    }
  ],
  "source_locator": "Myerson et al. 1986, DOI 10.1177/107110078600600504, primary classification and historical outcome series; Sivakumar et al. 2018, DOI 10.3928/01477447-20180213-07, proposed type D extension; Siddiqui et al. 2014, DOI 10.1148/rg.342125215, Myerson table and imaging assessment; Mahmoud et al. 2015, PMID 26224617, observer reliability; Engelmann et al. 2023, DOI 10.1016/j.fuspru.2023.07.007, reliability and non-applicability; current ACR Acute Trauma to the Foot Variant 5 for CT or MRI after normal or equivocal radiographs."
}

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