Knee dislocation: Difference between revisions
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==Background== | ==Background== | ||
*Popliteal artery injury | *Popliteal artery injury is common | ||
**Neurologic | **About 25% of cases | ||
*Spontaneous reduction | **Neurologic deficit may indicate vascular injury | ||
*Spontaneous reduction common | |||
**About 50% self-reduce, usually en route to ED | |||
===Types=== | ===Types=== | ||
*Anterior (40%) | *Anterior (40%) | ||
** | **Hyperextension | ||
** | **Associated injuries to PCL, ACL, and medial or lateral ligaments common | ||
*Posterior (33%) | *Posterior (33%) | ||
** | **Usually due to impact with dashboard during motor vehicle collision | ||
**Popliteal artery often injured | |||
*Lateral (18%) | *Lateral (18%) | ||
*Medial (4%) | *Medial (4%) | ||
==Clinical Features== | ==Clinical Features== | ||
* | *Instability in multiple directions | ||
* | *Evidence of collateral ligamentous injury combined with peroneal nerve palsy | ||
* | *History of high-energy mechanism | ||
* | **Patients with BMI > 40 commonly report low-energy mechanism | ||
*Affected knee may hyperextend relative to unaffected knee when leg is lifted by the foot | |||
===Associated Injuries=== | ===Associated Injuries=== | ||
*Popliteal injury | *Popliteal artery injury<ref>Tintinalli, J. E., Stapczynski, J. S., Ma, O. J., Yealy, D. M., Meckler, G. D., & Cline, D. (2016). Injuries to Bones and Joints In Tintinalli's emergency medicine: A comprehensive study guide (Eighth edition.) (pp1863-1864). New York: McGraw-Hill Education.</ref> | ||
** | **Cannot rule out based on normal distal pulses and Ankle Brachial Index (ABI) > 0.9 | ||
* | ***Requires definitive vascular imaging or serial exams | ||
*Neurologic injuries | |||
**Common peroneal nerve injury (25%) | **Common peroneal nerve injury (25%) | ||
***Test for | ***Test for: | ||
**Tibial nerve injured less | ****Sensation in 1st dorsal web space | ||
****Dorsiflexion of foot | |||
****Toe extension | |||
**Tibial nerve injured (less common) | |||
*[[Fractures]] | *[[Fractures]] | ||
**Femur and tibia most common | **Femur and tibia most common | ||
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==Evaluation== | ==Evaluation== | ||
[[File:PosteriorKneeDIsclocation.jpg|thumb|Plain lateral X-ray of the left knee showing a posterior knee dislocation]] | |||
[[File:Lateral-knee-dislocation-1.jpg|thumb|A lateral dislocation of the knee]] | |||
[[File:CTAngioOcclusionRtPop.jpg|thumb|CT angiogram 3D reconstruction, posterior view showing a normal artery on the left, and occlusion to right popliteal artery as a result of a knee dislocation]] | |||
*Knee x-ray (to rule-out fracture) | *Knee x-ray (to rule-out fracture) | ||
*Vascular assessment | *Vascular assessment | ||
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==Management== | ==Management== | ||
*Reduce immediately | *Reduce immediately | ||
**Posterior dislocation | **Avoid additional arterial injury by limiting excessive force during reduction | ||
===Posterior dislocation<ref name="Procedures for orthopedic emergencies">Davenport M. Procedures for orthopedic emergencies. In: Bond M, ed. Orthopedic Emergencies: Expert Management for the Emergency Physician. Cambridge: Cambridge University Press; October 31, 2013.</ref>=== | |||
#Grasp proximal tibia | |||
#Have assistant grasp distal femur and provide gentle counter-traction | |||
#Apply longitudinal traction to proximal tibia | |||
#Move proximal tibia anteriorly | |||
*Monitor for compartment syndrome | #Immobilize in 10-15 degrees of flexion | ||
** | #Assess neurovascular status | ||
** | #Obtain post-reduction imaging | ||
*** | |||
===Anterior dislocation<ref name="Procedures for orthopedic emergencies">Davenport M. Procedures for orthopedic emergencies. In: Bond M, ed. Orthopedic Emergencies: Expert Management for the Emergency Physician. Cambridge: Cambridge University Press; October 31, 2013.</ref>=== | |||
#Grasp distal femur | |||
#Have assistant grasp proximal tibia and provide gentle counter-traction | |||
#Pull distal femur proximally | |||
#Move distal femur anteriorly | |||
#Immobilize in 10-15 degrees of flexion | |||
#Assess neurovascular status | |||
#Obtain post-reduction imaging | |||
*Monitor for [[compartment syndrome]] | |||
**No pulses: reduce immediately | |||
**No pulses post reduction: surgical exploration | |||
***Ischemic time >8 hours has amputation rates as high as 86% | |||
==Disposition== | ==Disposition== | ||
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*Consider trauma consult depending on mechanism and additional injuries | *Consider trauma consult depending on mechanism and additional injuries | ||
==See Also== | |||
*[[Knee (Main)]] | |||
*[[Patella dislocation]] | |||
==External Links== | |||
*Standard: <https://emergencymedicinecases.com/occult-knee-injuries/> | *Standard: <https://emergencymedicinecases.com/occult-knee-injuries/> | ||
==References== | ==References== | ||
<references/> | <references/> | ||
*Review of Orthopaedics, 6th Edition, Mark D. Miller MD, Stephen R. Thompson MBBS MEd FRCSC, Jennifer Hart MPAS PA-C ATC, an imprint of Elsevier, Philadelphia, Copyright 2012 | *Review of Orthopaedics, 6th Edition, Mark D. Miller MD, Stephen R. Thompson MBBS MEd FRCSC, Jennifer Hart MPAS PA-C ATC, an imprint of Elsevier, Philadelphia, Copyright 2012 | ||
*AAOS Comprehensive Orthopaedic Review, Jay R. Leiberman. Published by American Academy of Orthopaedic Surgeons, Rosemont IL. Copyright 2009 | *AAOS Comprehensive Orthopaedic Review, Jay R. Leiberman. Published by American Academy of Orthopaedic Surgeons, Rosemont IL. Copyright 2009 | ||
*Levy BA, Fanelli GC, Whelan DB, Stannard JP, MacDonald PA, Boyd JL, Marx RG, Stuart MJ. Knee Dislocation Study Group. Controversies in the treatment of knee dislocations and multiligament reconstruction. J Am Acad Orthop Surg. 2009 Apr;17(4):197-206. http://www.ncbi.nlm.nih.gov/pubmed/19307669 | *Levy BA, Fanelli GC, Whelan DB, Stannard JP, MacDonald PA, Boyd JL, Marx RG, Stuart MJ. Knee Dislocation Study Group. Controversies in the treatment of knee dislocations and multiligament reconstruction. J Am Acad Orthop Surg. 2009 Apr;17(4):197-206. http://www.ncbi.nlm.nih.gov/pubmed/19307669 | ||
[[Category:Orthopedics]] | [[Category:Orthopedics]] |
Revision as of 06:39, 17 May 2019
Background
- Popliteal artery injury is common
- About 25% of cases
- Neurologic deficit may indicate vascular injury
- Spontaneous reduction common
- About 50% self-reduce, usually en route to ED
Types
- Anterior (40%)
- Hyperextension
- Associated injuries to PCL, ACL, and medial or lateral ligaments common
- Posterior (33%)
- Usually due to impact with dashboard during motor vehicle collision
- Popliteal artery often injured
- Lateral (18%)
- Medial (4%)
Clinical Features
- Instability in multiple directions
- Evidence of collateral ligamentous injury combined with peroneal nerve palsy
- History of high-energy mechanism
- Patients with BMI > 40 commonly report low-energy mechanism
- Affected knee may hyperextend relative to unaffected knee when leg is lifted by the foot
Associated Injuries
- Popliteal artery injury[1]
- Cannot rule out based on normal distal pulses and Ankle Brachial Index (ABI) > 0.9
- Requires definitive vascular imaging or serial exams
- Cannot rule out based on normal distal pulses and Ankle Brachial Index (ABI) > 0.9
- Neurologic injuries
- Common peroneal nerve injury (25%)
- Test for:
- Sensation in 1st dorsal web space
- Dorsiflexion of foot
- Toe extension
- Test for:
- Tibial nerve injured (less common)
- Common peroneal nerve injury (25%)
- Fractures
- Femur and tibia most common
- Check hip and ankle joints for associated fracture
- Avulsion fractures common
- Compartment syndrome risk high with vascular compromise
Differential Diagnosis
Knee diagnoses
Acute knee injury
- Knee dislocation
- Knee fractures
- Meniscus and ligament knee injuries
- Patella dislocation
- Patellar tendonitis
- Patellar tendon rupture
- Quadriceps tendon rupture
Nontraumatic/Subacute
- Arthritis
- Gout and Pseudogout
- Osgood-Schlatter disease
- Patellofemoral syndrome (Runner's Knee)
- Patellar tendonitis (Jumper's knee)
- Pes anserine bursitis
- Popliteal cyst (Bakers cyst)
- Prepatellar bursitis (nonseptic)
- Septic bursitis
- Septic joint
- DVT
Evaluation
- Knee x-ray (to rule-out fracture)
- Vascular assessment
- Assess popliteal and distal pulses
- Measure ABIs
- ABI >0.9 - serial exams
- ABI <0.9 - arterial duplexes or CT angio
- Consider CT Angiography:
- Asymmetric pulses
- ABI <0.9
- Clinical concern of vascular injury (ischemia, hemorrhage, or expanding hematoma)
Management
- Reduce immediately
- Avoid additional arterial injury by limiting excessive force during reduction
Posterior dislocation[2]
- Grasp proximal tibia
- Have assistant grasp distal femur and provide gentle counter-traction
- Apply longitudinal traction to proximal tibia
- Move proximal tibia anteriorly
- Immobilize in 10-15 degrees of flexion
- Assess neurovascular status
- Obtain post-reduction imaging
Anterior dislocation[2]
- Grasp distal femur
- Have assistant grasp proximal tibia and provide gentle counter-traction
- Pull distal femur proximally
- Move distal femur anteriorly
- Immobilize in 10-15 degrees of flexion
- Assess neurovascular status
- Obtain post-reduction imaging
- Monitor for compartment syndrome
- No pulses: reduce immediately
- No pulses post reduction: surgical exploration
- Ischemic time >8 hours has amputation rates as high as 86%
Disposition
- Institution will dictate admission process
- Suggested algorithm
- If: Strong pulses + ABI >0.9 + normal doppler, admit for obs and serial vascular exams
- If: Good perfusion + asymmetric pulses or ABI <0.9 or abnormal doppler, consult vascular surgery + obtain CTA
- If: Weak pulses or signs of ischemia = emergent vascular surgery consult and OR
- Suggested algorithm
- Consider trauma consult depending on mechanism and additional injuries
See Also
External Links
References
- ↑ Tintinalli, J. E., Stapczynski, J. S., Ma, O. J., Yealy, D. M., Meckler, G. D., & Cline, D. (2016). Injuries to Bones and Joints In Tintinalli's emergency medicine: A comprehensive study guide (Eighth edition.) (pp1863-1864). New York: McGraw-Hill Education.
- ↑ 2.0 2.1 Davenport M. Procedures for orthopedic emergencies. In: Bond M, ed. Orthopedic Emergencies: Expert Management for the Emergency Physician. Cambridge: Cambridge University Press; October 31, 2013.
- Review of Orthopaedics, 6th Edition, Mark D. Miller MD, Stephen R. Thompson MBBS MEd FRCSC, Jennifer Hart MPAS PA-C ATC, an imprint of Elsevier, Philadelphia, Copyright 2012
- AAOS Comprehensive Orthopaedic Review, Jay R. Leiberman. Published by American Academy of Orthopaedic Surgeons, Rosemont IL. Copyright 2009
- Levy BA, Fanelli GC, Whelan DB, Stannard JP, MacDonald PA, Boyd JL, Marx RG, Stuart MJ. Knee Dislocation Study Group. Controversies in the treatment of knee dislocations and multiligament reconstruction. J Am Acad Orthop Surg. 2009 Apr;17(4):197-206. http://www.ncbi.nlm.nih.gov/pubmed/19307669