Knee dislocationMANAGEMENT

THIGH & KNEE · 12 SECTIONS

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454 items

☷ Legend

01Approach to the Critical Patient/attcp67

Immediate priorities

›Limb threat and resuscitation framing

›High risk vascular injury until proven otherwise

›Popliteal artery injury risk even with spontaneous reduction

›Ischemia time sensitivity

›Initial monitoring

›Continuous ECG

›Pulse oximetry

›Noninvasive blood pressure cycling

›Two large bore IV

›Pain control and anxiolysis

›IV opioid titration with cardiorespiratory monitoring

›Early plan for procedural sedation if reduction required

›Remove external constrictors

›Clothing removal around knee

›Jewelry removal if lower extremity edema expected

›Limb positioning

›Knee supported

›Avoid forced extension if deformity present

›Immediate orthopedic and vascular escalation triggers

›Pulseless limb

›Diminishing Doppler signal

›Expanding hematoma

›Active hemorrhage

›Hard neurologic deficit progression

Neurovascular time stamps

›Neurovascular documentation checkpoints

›Pre reduction exam time stamp

›Dorsalis pedis pulse palpation

›Posterior tibial pulse palpation

›Doppler signals if pulses not palpable

›Capillary refill

›Skin temperature

›Foot color

›Ankle brachial index if stable

›Peroneal nerve status

›Dorsiflexion strength

›Great toe extension strength

›Dorsum of foot sensation

›Tibial nerve status

›Plantarflexion strength

›Plantar foot sensation

›Post reduction exam time stamp

›Repeat pulses and Doppler

›Repeat motor and sensory testing

›Repeat cap refill and perfusion

Hemodynamic and vascular decision points

›Vascular injury screening pathway

›Hard signs

›Absent distal pulses

›Pulsatile bleeding

›Expanding hematoma

›Audible bruit or palpable thrill

›Distal ischemia

›Soft signs

›History of hemorrhage at scene

›Stable nonexpanding hematoma

›Neurologic deficit not explained by swelling alone

›ABI below threshold

›ABI interpretation

›ABI 0.90 or higher with normal exam

›Serial neurovascular exams pathway

›ABI below 0.90 or abnormal exam

›CT angiography pathway

›Compartment syndrome vigilance

›Pain out of proportion

›Pain with passive stretch ankle and toes

›Tense compartments

›Progressive paresthesia

›Diminishing pulses late finding

02History/hx44

Mechanism and timeline

›Injury context

›High energy mechanism

›Motor vehicle collision

›Dashboard mechanism

›Pedestrian struck

›Fall from height

›Low energy mechanism with obesity risk

›Ground level fall with twisting

›Sports pivot injury with deformity

›Time of injury

›Time since last normal distal perfusion

›Time since any spontaneous reduction

›Prehospital course

›EMS noted deformity

›EMS reduction attempt

›Splinting and traction used

›Pulses before and after any manipulation

Symptoms and red flags

›Limb threat symptoms

›Cool foot

›Pallor

›Numbness or tingling

›Weakness ankle or toes

›Severe pain despite analgesia

›Associated injury symptoms

›Hip pain

›Ankle pain

›Head injury symptoms

›Chest or abdominal pain

Risk modifiers

›Bleeding and thrombosis context

›Anticoagulants

›Antiplatelets

›Bleeding disorder

›Baseline limb function

›Prior knee instability

›Prior knee surgery

›Vascular history

›Peripheral arterial disease

›Prior bypass

›Diabetes with neuropathy

›Infection risk if open injury

›Wound contamination

›Farm exposure

›Water exposure

›Tetanus status

03Physical Exam/exam58

Primary limb exam

›Limb survey

›Deformity

›Anterior tibial displacement pattern suspicion

›Posterior tibial displacement pattern suspicion

›Medial or lateral displacement pattern suspicion

›Rotatory displacement pattern suspicion

›Skin

›Open wound

›Tenting

›Blanching threatened skin

›Ecchymosis

›Effusion and swelling

›Rapid tense swelling concern

›Hemarthrosis concern

Neurovascular exam

›Perfusion and pulses

›Dorsalis pedis pulse

›Palpable

›Doppler only

›Absent

›Posterior tibial pulse

›Palpable

›Doppler only

›Absent

›Capillary refill

›Normal

›Delayed

›Skin temperature

›Symmetric

›Cool distal

›ABI if stable

›Bilateral measurement

›Recheck after reduction

›Motor testing

›Peroneal nerve

›Ankle dorsiflexion

›Great toe extension

›Tibial nerve

›Ankle plantarflexion

›Toe flexion

›Sensory testing

›Peroneal nerve territory

›First web space

›Dorsum of foot

›Tibial nerve territory

›Plantar foot

Knee stability and associated injuries

›Gross instability markers

›Multidirectional laxity

›Inability to bear weight due to instability

›Extensor mechanism

›Straight leg raise

›Patellar position

›Joint above and below

›Hip exam

›Ankle exam

›PITFALLS

›Normal pulses do not exclude intimal popliteal injury

›Reduced knee can hide vascular compromise

›Peroneal nerve injury common and can be missed without focused exam

04Differential Diagnosis/ddx17

Traumatic knee and limb threats

›Knee dislocation traumatic

›ICD 10 S83.1 dislocation of knee

›SNOMED CT knee dislocation concept

›Vascular injury

›Popliteal artery injury

›Popliteal vein injury

›Compartment syndrome leg

›Fracture dislocation variants

›Tibial plateau fracture with instability

›Distal femur fracture with instability

›Patellar dislocation with hemarthrosis

›Tendon rupture mimics

›Quadriceps tendon rupture

›Patellar tendon rupture

Nontraumatic mimics

›Spontaneous hemarthrosis on anticoagulants

›Septic arthritis if atraumatic swelling and fever

›Crystal arthritis if atraumatic swelling pattern

05Laboratory Tests/lt20

Trauma baseline when indicated

›Selective labs

›Hemorrhage concern labs

›Complete blood count for anemia or bleeding

›Type and screen if transfusion possible

›Procedural sedation pathway labs by local protocol

›Point of care glucose if altered mental status

›Anticoagulation context

›INR if warfarin use

›Creatinine for DOAC clearance context

Ischemia and crush considerations

›Reperfusion risk labs when prolonged ischemia concern

›Potassium

›Hyperkalemia risk after reperfusion

›Creatinine

›Acute kidney injury risk

›Creatine kinase

›Rhabdomyolysis risk

›Venous blood gas if shock concern

›Lactate for hypoperfusion

PITFALLS

›Normal labs do not exclude vascular injury

›CK can be normal early after ischemia

06Diagnostic Tests/dt43

Scoring Systems

›Classification and vascular screening

›Schenck classification knee dislocation

›KD I single cruciate injury

›KD II bicruciate injury

›KD III medial or lateral plus bicruciate

›KD IV bicruciate plus both collateral ligaments

›KD V knee dislocation with periarticular fracture

›ABI thresholds

›ABI 0.90 or higher low likelihood major arterial injury

›ABI below 0.90 increased likelihood arterial injury

›Hard signs vascular injury

›Immediate vascular surgery involvement

›CT angiography bypass if unstable and going to OR

Radiographs

›Plain radiography knee and long bone coverage

›Knee series

›AP view

›Lateral view

›Sunrise or Merchant view if patellar concern and tolerated

›Femur and tibia fibula coverage

›Joint above and below principle for long bone injury suspicion

›Post reduction imaging

›Confirm alignment and detect fractures

MRI

›Ligament and soft tissue characterization

›Multiligament injury mapping for operative planning

›ACL

›PCL

›MCL

›LCL and posterolateral corner

›Meniscal injury

›Cartilage injury

›Timing coordination with orthopedics

›CT and CT angiography pathways

›CT knee

›Occult fracture suspicion after high energy mechanism

›Tibial plateau fracture detail for operative planning

›CT angiography lower extremity

›Abnormal pulses

›ABI below 0.90

›Soft signs with concerning mechanism

›Hard signs if stable enough for imaging

›Alternative imaging

›Duplex ultrasound when CT angiography not available and patient stable

›Formal angiography when endovascular intervention planned

07Disposition/dispo17

Level of care and transfer

›Admission default pathway

›Multiligament injury expectation

›Serial neurovascular exams requirement

›Pain control requirement

›MRI planning and operative coordination

›Immediate transfer triggers

›Vascular injury suspicion requiring vascular surgery capability

›Compartment syndrome concern requiring fasciotomy capability

›Open knee dislocation

›Irreducible dislocation

›Persistent neurologic deficit progression

Observation and monitoring

›Serial exam cadence

›Repeat pulses and Doppler at defined intervals per local protocol

›Repeat ABI after reduction and immobilization

›Immobilization disposition

›Long leg immobilization in near extension per orthopedic plan

›Non weight bearing until specialist reassessment

08Treatment/t99

Immediate life-saving interventions

›Limb ischemia response

›If pulseless or ischemic limb then immediate reduction attempt

›Parallel orthopedic and vascular consultation

›Prepare for emergent OR if perfusion not restored

›If hemodynamic instability then trauma resuscitation pathway

›Massive transfusion protocol criteria per local protocol

›Warmed fluids and active warming

›Analgesia and sedation readiness

›Airway and monitoring setup for procedural sedation

›Capnography

›Suction setup

›BVM and airway adjuncts

Immobilization and Splinting

›Immobilization strategy

›Posterior long leg splint

›Knee in slight flexion or near extension per stability

›Extra padding at malleoli and heel

›Knee immobilizer option

›Only if stable post reduction and swelling allows

›Principles

›Avoid circumferential casting in acute swelling phase

›Post splint neurovascular recheck

›Elevation and ice if soft tissue swelling

Reduction

›Reduction decision and technique

›Indications

›Obvious deformity

›Neurovascular compromise

›Threatened skin

›Caution triggers

›Open injury

›Antibiotics and tetanus pathway first when feasible

›Suspected vascular hard signs

›Parallel vascular involvement

›Analgesia and anesthesia options

›IV analgesia titration

›Fentanyl IV 25 to 50 micrograms

›Repeat every 3 to 5 minutes to effect

›Typical total 100 to 200 micrograms

›Hydromorphone IV 0.2 to 0.5 mg

›Repeat every 10 minutes to effect

›Typical total 1 to 2 mg

›Procedural sedation options

›Ketamine IV 1 to 2 mg per kg

›Additional 0.5 mg per kg as needed

›Emergence reaction mitigation per local protocol

›Propofol IV 0.5 to 1 mg per kg

›Additional 0.25 to 0.5 mg per kg as needed

›Hypotension risk monitoring

›Etomidate IV 0.1 to 0.15 mg per kg

›Additional 0.05 mg per kg as needed

›Myoclonus consideration

›Minimum monitoring standards alignment

›ACEP procedural sedation policy alignment Level B

›Capnography use when available

›Continuous cardiorespiratory monitoring

›Technique principles

›Inline traction

›Countertraction at thigh

›Gentle reversal of displacement direction

›Avoid repeated forceful attempts

›Post reduction requirements

›Immediate pulse reassessment

›Immediate Doppler reassessment if pulses not palpable

›Repeat motor and sensory exam

›Post reduction radiographs

›Immobilization in position of stability

›Failed reduction pathway

›Persistent deformity

›Urgent orthopedics

›Persistent pulseless limb after reduction

›Immediate vascular surgery

›Emergent OR pathway

Open fracture medications and timing

›Open injury prophylaxis

›Antibiotics timing

›First dose as early as possible

›Gustilo based antibiotic approach

›Type I or II suspected

›Cefazolin IV 2 g

›Repeat every 8 hours per local protocol

›Type III suspected

›Cefazolin IV 2 g

›Repeat every 8 hours per local protocol

›Gentamicin IV 5 to 7 mg per kg

›Once daily dosing per local protocol

›Soil or farm contamination

›Add anaerobic coverage per local protocol

›Tetanus prophylaxis

›Unknown or incomplete immunization

›Tetanus toxoid vaccine

›Tetanus immune globulin if indicated

DVT prophylaxis when relevant

›Thrombosis risk planning

›High risk features

›Lower limb immobilization

›Multiligament injury requiring surgery

›Reduced mobility

›Pharmacologic prophylaxis coordination

›Ortho service protocol

›Vascular injury pathway considerations

›Mechanical prophylaxis

›Intermittent pneumatic compression if admitted and no contraindication

09Special Populations/sp26

Pregnancy

›Maternal and fetal considerations

›Left lateral tilt positioning if supine hypotension concern

›Analgesic selection

›Avoid NSAIDs in later gestation per obstetric guidance

›Imaging and radiation

›Shielding when feasible

›CT angiography if limb threat and benefits outweigh risks

›Consultation

›Obstetrics involvement for viable gestation or trauma activation criteria

Geriatric

›Older adult considerations

›Low energy knee dislocation risk in obesity and frailty

›Higher vascular disease prevalence

›Lower threshold for CT angiography despite palpable pulses

›Delirium risk with opioids and sedatives

›Smaller titrated dosing

›Disposition

›Higher admission threshold for mobility and safety

Pediatrics

›Pediatric considerations

›Physeal injury risk with apparent dislocation pattern

›Salter Harris injury mimic

›Weight based analgesia and sedation

›Ketamine dosing per kg and age specific monitoring

›Nonaccidental trauma consideration when mechanism inconsistent

›Vascular assessment challenges

›Doppler and ABI feasibility limits

›Lower threshold for specialist involvement

10Background/b24

Epidemiology

›Frequency and context

›Rare injury overall

›High association with popliteal artery injury compared with other knee trauma

›High association with peroneal nerve injury

Pathophysiology

›Mechanism and anatomic threats

›Tibiofemoral articulation disruption

›Multiligament disruption common

›Popliteal artery tethering at adductor hiatus and soleal arch

›Intimal tear mechanism with traction

›Thrombosis progression despite initial perfusion

›Peroneal nerve vulnerability at fibular neck

Therapeutic Considerations

›Time dependence

›Earlier reperfusion associated with limb salvage

›Prolonged ischemia increases amputation risk

›Reduction rationale

›Restore alignment

›Relieve tension on neurovascular bundle

›Decrease skin compromise

›Vascular screening rationale

›Physical exam alone insufficient to exclude arterial injury

›ABI based selective imaging strategy commonly recommended in trauma pathways

›Evidence framing

›Expert consensus support for immediate reduction when ischemia present

›Class I style recommendation alignment for emergent limb reperfusion decisions

11Patient Discharge Instructions/pdi29

Copy discharge instructions

›Discharge rare and specialist directed

›Usually admitted or transferred for observation and operative planning

›If discharged under specialist plan

›Immobilization care

›Keep splint or immobilizer on

›Keep dry

›Do not adjust tight wraps without instructions

›Weight bearing

›Non weight bearing

›Crutches or walker use

›Elevation

›Leg elevated above heart when resting

›Ice

›15 to 20 minutes at a time

›Several times daily if swelling

›Pain plan

›Acetaminophen dosing per label and local guidance

›Avoid NSAIDs if instructed by surgeon

›Return immediately for

›Increasing pain not controlled

›New numbness or tingling

›New weakness toes or ankle

›Cool or pale foot

›Increasing tightness in calf

›Splint too tight or wet

›Fever or wound drainage if open injury

›Follow up

›Orthopedics within 24 to 72 hours or as arranged

›Vascular follow up if imaging abnormal or repair performed

12References/r10

Clinical guidelines and core sources

›Evidence and guidelines

›ATLS trauma evaluation principles for high energy extremity injury

›Trauma society guidance on knee dislocation vascular screening using ABI and selective imaging

›ACEP clinical policy procedural sedation and analgesia in the emergency department

›Orthopedic references for multiligament knee injury classification and management

›Vascular surgery references for extremity arterial injury hard and soft signs and imaging pathways

Decision tools and education sources

›Decision support and reviews

›Review articles on popliteal artery injury incidence after knee dislocation

›Reviews on ABI performance for excluding major arterial injury in blunt extremity trauma

›Surgical texts on KD Schenck classification and operative timing

Evidence & Review

Reviewed by SymptomDx Medical Team · Last reviewed March 6, 2026

SymptomDx is an educational tool for medical professionals. It does not replace clinical judgment. Verify all clinical data and drug dosages with authoritative sources.