Acute knee injury - Revision history

Danbot: Strip excess bold

2026-03-22T09:31:19Z

Strip excess bold

← Older revision		Revision as of 09:31, 22 March 2026
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	==Clinical Features==		==Clinical Features==
	*Acute pain, swelling, inability to bear weight		*Acute pain, swelling, inability to bear weight
	*~~'''~~Immediate large effusion~~'''~~ (<2 hours) suggests hemarthrosis → ACL tear, fracture, or peripheral meniscal tear		*Immediate large effusion (<2 hours) suggests hemarthrosis → ACL tear, fracture, or peripheral meniscal tear
	*~~'''~~Locked knee~~'''~~ (inability to fully extend) → meniscal tear with displaced fragment		*Locked knee (inability to fully extend) → meniscal tear with displaced fragment
	*~~'''~~Giving way/instability~~'''~~ → ligamentous injury		*Giving way/instability → ligamentous injury
	*~~'''~~Patellar apprehension~~'''~~ → patellar subluxation/dislocation		*Patellar apprehension → patellar subluxation/dislocation

	===Key Exam Maneuvers===		===Key Exam Maneuvers===
	*~~'''~~Lachman test:~~'''~~ Most sensitive for ACL tear (anterior tibial translation at 20-30° flexion)		*Lachman test: Most sensitive for ACL tear (anterior tibial translation at 20-30° flexion)
	*~~'''~~Posterior drawer:~~'''~~ PCL integrity		*Posterior drawer: PCL integrity
	*~~'''~~Valgus stress (30°):~~'''~~ MCL integrity		*Valgus stress (30°): MCL integrity
	*~~'''~~Varus stress (30°):~~'''~~ LCL integrity		*Varus stress (30°): LCL integrity
	*~~'''~~McMurray test:~~'''~~ Meniscal tear (joint line tenderness is more sensitive)		*McMurray test: Meniscal tear (joint line tenderness is more sensitive)

	==Differential Diagnosis==		==Differential Diagnosis==
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	{{Knee x-rays}}		{{Knee x-rays}}
	*X-ray if Ottawa knee rules positive		*X-ray if Ottawa knee rules positive
	**~~'''~~Lipohemarthrosis~~'''~~ on lateral view (fat-fluid level in suprapatellar bursa) = occult fracture until proven otherwise		**Lipohemarthrosis on lateral view (fat-fluid level in suprapatellar bursa) = occult fracture until proven otherwise
	*MRI for suspected ligamentous or meniscal injury (usually outpatient)		*MRI for suspected ligamentous or meniscal injury (usually outpatient)
	*Aspiration if large tense effusion causing significant pain: send cell count, culture, crystals		*Aspiration if large tense effusion causing significant pain: send cell count, culture, crystals

	==Management==		==Management==
	*If x-rays ~~'''~~positive~~'''~~ (fracture): treat underlying condition, splint, orthopedic consult		*If x-rays positive (fracture): treat underlying condition, splint, orthopedic consult
	*If x-rays ~~'''~~negative~~'''~~ or not indicated per [[Ottawa knee rules]]:		*If x-rays negative or not indicated per [[Ottawa knee rules]]:
	**Perform full ligamentous exam		**Perform full ligamentous exam
	**~~'''~~Stable exam:~~'''~~ RICE (rest, ice, compression, elevation), crutches if unable to bear weight, NSAIDs		**Stable exam: RICE (rest, ice, compression, elevation), crutches if unable to bear weight, NSAIDs
	**~~'''~~Unstable exam or unable to evaluate~~'''~~ (pain/swelling): knee immobilizer + RICE, weight-bearing as tolerated with crutches		**Unstable exam or unable to evaluate (pain/swelling): knee immobilizer + RICE, weight-bearing as tolerated with crutches

	==Disposition==		==Disposition==

Danbot: Expand with concise EM-focused content: exam maneuvers, red flags, management algorithm

2026-03-21T01:18:37Z

Expand with concise EM-focused content: exam maneuvers, red flags, management algorithm

← Older revision		Revision as of 01:18, 21 March 2026
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	==Background==		==Background==
	{{Knee ligaments}}		{{Knee ligaments}}
			*Knee injuries are among the most common musculoskeletal complaints in the ED
			*Mechanism of injury guides the differential (valgus stress, hyperextension, twisting, direct impact)

	==Clinical Features==		==Clinical Features==
	*Acute ~~trauma and~~ pain to knee		*Acute pain, swelling, inability to bear weight
			*'''Immediate large effusion''' (<2 hours) suggests hemarthrosis → ACL tear, fracture, or peripheral meniscal tear
			*'''Locked knee''' (inability to fully extend) → meniscal tear with displaced fragment
			*'''Giving way/instability''' → ligamentous injury
			*'''Patellar apprehension''' → patellar subluxation/dislocation

			===Key Exam Maneuvers===
			*'''Lachman test:''' Most sensitive for ACL tear (anterior tibial translation at 20-30° flexion)
			*'''Posterior drawer:''' PCL integrity
			*'''Valgus stress (30°):''' MCL integrity
			*'''Varus stress (30°):''' LCL integrity
			*'''McMurray test:''' Meniscal tear (joint line tenderness is more sensitive)

	==Differential Diagnosis==		==Differential Diagnosis==
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	{{Ottawa knee rules}}		{{Ottawa knee rules}}
	{{Knee x-rays}}		{{Knee x-rays}}
			*X-ray if Ottawa knee rules positive
			**'''Lipohemarthrosis''' on lateral view (fat-fluid level in suprapatellar bursa) = occult fracture until proven otherwise
			*MRI for suspected ligamentous or meniscal injury (usually outpatient)
			*Aspiration if large tense effusion causing significant pain: send cell count, culture, crystals

	==Management==		==Management==
	*If ~~xrays are <u>~~positive~~</u>~~ (~~when indicated~~)		*If x-rays '''positive''' (fracture): treat underlying condition, splint, orthopedic consult
	**Treat underlying condition		*If x-rays '''negative''' or not indicated per [[Ottawa knee rules]]:
	*If ~~xrays are <u>~~negative~~</u>~~ or not indicated [[Ottawa knee rules]]		**Perform full ligamentous exam
	**Do full ~~knee~~ exam ~~to check for ligamentous/meniscal instability:~~		**'''Stable exam:''' RICE (rest, ice, compression, elevation), crutches if unable to bear weight, NSAIDs
	***Negative exam → RICE		**'''Unstable exam or unable to evaluate''' (pain/swelling): knee immobilizer + RICE, weight-bearing as tolerated with crutches
	***Positive exam or unable to evaluate ~~secondary to~~ pain/swelling → knee ~~brace~~ + RICE

	==Disposition==		==Disposition==
	*~~Depends on diagnosis; most often results in~~ outpatient ~~ortho~~ referral		*Most acute knee injuries are managed as outpatient with orthopedics referral
			*'''ED consult/admit:''' [[Knee dislocation]] (check vascular status — popliteal artery injury), open fractures, [[septic arthritis]]
			*Urgent orthopedics follow-up (within 1 week) for suspected ACL/meniscal tears, locked knee

	==See Also==		==See Also==
	*[[Knee diagnoses]]		*[[Knee diagnoses]]
			*[[Knee dislocation]]
	~~==External Links==~~		*[[Patellar dislocation]]
			*[[ACL tear]]

	==References==		==References==

Mholtz: Text replacement - "-->" to "→"

2017-11-17T10:28:30Z

Text replacement - "-->" to "→"

← Older revision		Revision as of 10:28, 17 November 2017
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	*If xrays are <u>negative</u> or not indicated [[Ottawa knee rules]]		*If xrays are <u>negative</u> or not indicated [[Ottawa knee rules]]
	**Do full knee exam to check for ligamentous/meniscal instability:		**Do full knee exam to check for ligamentous/meniscal instability:
	***Negative exam ~~-->~~ RICE		***Negative exam → RICE
	***Positive exam or unable to evaluate secondary to pain/swelling ~~-->~~ knee brace + RICE		***Positive exam or unable to evaluate secondary to pain/swelling → knee brace + RICE

	==Disposition==		==Disposition==

Mholtz at 14:19, 16 November 2017

2017-11-16T14:19:21Z

← Older revision		Revision as of 14:19, 16 November 2017
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	==References==		==References==
	<references/>		<references/>

			[[Category:Orthopedics]]

Rossdonaldson1: /* Management */

2017-11-09T06:49:13Z

Management

← Older revision		Revision as of 06:49, 9 November 2017
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	==Management==		==Management==
	*~~Knee brace, ice, elevation, ambulation as soon as comfortable~~		*If xrays are <u>positive</u> (when indicated)
	**~~Full knee immobilization generally~~ not indicated for ~~single ligament injuries~~		**Treat underlying condition
			*If xrays are <u>negative</u> or not indicated [[Ottawa knee rules]]
			**Do full knee exam to check for ligamentous/meniscal instability:
			***Negative exam --> RICE
			***Positive exam or unable to evaluate secondary to pain/swelling --> knee brace + RICE

	==Disposition==		==Disposition==

Rossdonaldson1: /* Disposition */

2017-11-09T06:41:51Z

Disposition

← Older revision		Revision as of 06:41, 9 November 2017
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	==Disposition==		==Disposition==
			*Depends on diagnosis; most often results in outpatient ortho referral

	==See Also==		==See Also==

Rossdonaldson1: /* Management */

2017-11-09T06:40:59Z

Management

← Older revision		Revision as of 06:40, 9 November 2017
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	==Management==		==Management==
			*Knee brace, ice, elevation, ambulation as soon as comfortable
			**Full knee immobilization generally not indicated for single ligament injuries

	==Disposition==		==Disposition==

Rossdonaldson1 at 06:35, 9 November 2017

2017-11-09T06:35:34Z

← Older revision		Revision as of 06:35, 9 November 2017
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	==Clinical Features==		==Clinical Features==
			*Acute trauma and pain to knee

	==Differential Diagnosis==		==Differential Diagnosis==

Rossdonaldson1: /* See Also */

2017-11-09T04:03:18Z

Rossdonaldson1: /* Evaluation */

2017-11-09T04:02:11Z

Evaluation

← Older revision		Revision as of 04:02, 9 November 2017
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	==Evaluation==		==Evaluation==
			{{Ottawa knee rules}}
	{{Knee x-rays}}		{{Knee x-rays}}

← Older revision		Revision as of 04:03, 9 November 2017
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	==See Also==		==See Also==
			*[[Knee diagnoses]]

	==External Links==		==External Links==