Knee Dislocation

William R. Creevy, MS, MDAssistant Professor and Vice Chairman

Department of Orthopaedic SurgeryBoston University Medical Center

Mark A. Neault, MDBrian D. Busconi, MD

University of Massachusetts Medical School

Knee Dislocation

“It is unlikely that any single physician personally cares for more than a few

knee dislocations in a lifetime of practice”

JBJS 1971

Epidemiology

AUTHOR CENTER CASES REFERENCE

Frassica 1992 Mayo Clinic 14 2 million admissions

Wascher 1997 New Mexico 33 5 years

Eastlack 1997 US Army 28 5 years

Moore 1990 Denver 0.12 % of all trauma admissions

Epidemiology true incidence is probably underreported 20% - 50% spontaneously reduced practice environment

trauma center sports medicine practice general orthopaedics

Anatomy 4 ligament structures

ACL PCL MCL PLC

LCL popliteus biceps femoris ITB

Anatomy popliteal artery adductor hiatus soleus arch tension injury

hyperextension posterior

Anatomy peroneal nerve biceps femoris fibular neck tension

varus direct injury

Pathomechanics mechanism of injury

low energy - sports high energy - MVA position of knee direction of applied force degree of exagerrated motion

hyperextension varus/valgus anterior flexion + posterior force posterior

Pathomechanics Kennedy, 1963

10 cadaveric knee specimens hyperextension

ACL PCL posterior capsule @ 30º popliteal artery @ 50º

Pathomechanics avulsion injuries of cruciates

clinical studies: Sisto (1985) & Frassica (1992) combined data

80% PCL avulsion (“femoral peel off”) 30% ACL avulsion

Schenck (1999) cadaveric cruciate injury model hyperextension with variable strain (velocity)

high (5400%/sec): stripping lesion femur low (100%/sec): mid-substance tear

Classification purpose

determine prognosis (outcome) guide treatment

historical: Kennedy (1963) tibial position with respect to femur

visual inspection radiograhs

documented dislocation both cruciates torn

Positional Classification: Problems 20% - 50% reduced at presentation does not define exact status of ligaments

collateral: MCL vs. LCL-PLC knee dislocation with intact PCL

Myers (1975), Shelbourne (1992), Cooper (1992) ACL + collateral “simple treatment” vascular injury less likely?

knee dislocation with intact ACL Schenck (1992)

fracture dislocation patterns: Moore (1981)

Classification: Structures Involved

V

C

N

III L ACL / PCL / LCL+PLC MCL intact

IV ACL / PCL / MCL / LCL+PLC

III M ACL / PCL / MCL LCL+PLC intact

Schenck 1992

II

arterial injury

nerve injury

fracture dislocation

Anatomic Classification of Knee Dislocations

I single cruciate + collateralACL + collateralPCL + collateral

ACL / PCL collaterals intact

Anatomic Classification combined series application

Walker (1994): 13 patients Eastlack (1997): 28 patients

type III most common III L poor outcome vs. III M

duration of disability arthrofibrosis Sickness Impact Profile Lysholm and IKDC scales

Utility of Anatomic Classification

requires surgeon to focus on what is torn directs treatment to what is injured accurate discussion of injuries among

clinicians comparison of similar injuries within wide

spectrum of knee dislocations

Associated Injuries: Vascular high incidence combined results of 11 published series

average: 32% range: 8% to 64%

pathology intimal tear arterial disruption

direction of dislocation: no difference low velocity: decreased incidence?

Associated Injuries: Vascular Jones (1979)

“significant” arterial injury 4 of 15 (27%) patients “normal” post-reduction pulses liberal arteriography

Kendal (1993) surgical arterial injuries always present with change in vascularity: physical exam

pulse deficit diminished capillary refill

Lynch (1991) doppler pressure measurement ABI > 0.9 no clinically important vascular injuries selective arteriography

Physical Examination Inspection

± Obvious deformity Consider immediate reduction Hint: Coexistent varus/valgus instability in extension = ACL/PCL

injury ± Hemarthrosis

May be absent 2° to capsular disruption Popliteal ecchymosis Evaluate skin Hyperextension

Physical Examination Vascular Exam

Dorsalis pedis and posterior tibial arteries Pulse absent

Consider immediate closed reduction– If still absent O.R. for exploration– If pulse returns consider angiogram vs. observation

8 hour ischemic time is MAXIMUM Pulse present

A.B.I. > 0.9 observe A.B.I < 0.9 angiogram &/or exploration

Associated Injuries: Vascular DeBakey (1946)

WWII 80% amputation rate popliteal artery injury not revascularized

Green (1977) knee dislocation with popliteal artery injury 90% amputation if not revascularized within 8 hours

WHAT IS THE ROLE OF ANGIOGRAPHY?

Vascular Injuries: Principles1. Evaluate and document the vascular status (DP/PT

pulses and capillary refill) in any patient with a proven or suspected knee dislocation.

2. Once the dislocation is reduced the circulation should be re-evaluated.

3. Revascularization should be performed within 8 hours.

4. Arteriography should not delay surgical reanastomosis.

Vascular Injuries: Principles5. It is unacceptable to suggest spasm as a cause for

decreased or absent pulses in an attempt to justify observation.

6. If arterial insufficiency or abnormality is present, there is a vascular injury.

7. Arterial injury is treated with excision of the damaged segment and reanastomosis with reverse saphenous vein graft.

8. An experienced vascular surgeon should be utilized to verify clinical findings and interpret studies.

Vascular Injuries: Recommendations[A] ischemic limb after reduction

immediate surgical exploration injury and location predictable arteriogram: only if additional associated proximal injury

[B] abnormal vascular status - viable limb diminished pulses decreased capillary refill ABI < 0.9 “urgent” arteriogram

Vascular Injuries: Recommendations[C] normal vascular status and no ligament or

extremity surgery normal PT/DP pulses and normal capillary refill ABI > 0.90 careful observation with serial exams

vascular surgery and invasive radiology “available” MRA/MRI

evaluate for non-occlusive (intimal) injury sensitivity and specificity uncertain arteriogram if abnormal

Vascular Injuries: Recommendations[D] normal vascular status - potential or

planned ligament or extremity surgery normal PT/DP pulses and normal capillary refill ABI > 0.90 careful observation with serial exams

vascular surgery and invasive radiology “available” MRA/MRI as part of pre-operative evaluation routine arteriogram within 24 - 48 hours intimal injury

anticoagulation no tourniquet limited and delayed surgery (10-14 days) no endoscopic PCL (tibial tunnel)

Case Example: KD-IIIM

Physical Examination

Neurologic Exam Peroneal Nerve

EHL &/or tibialis anterior strength Dorsal 1st web space sensation

Tibial Nerve FHL &/or gastroc/soleus strength Lateral border & plantar surface of foot sensation

Associated Injuries: Peroneal Nerve incidence: 14% to 35% most common with Type III L (varus) traction injury disruption rare: nerve repair precluded usually axonotmesis

observation poor prognosis (<25% functional return) 12-18 months role of delayed decompression?

Associated Injuries: Peroneal Nerve nerve injury has an important influence on

surgical decision making absent peroneal never function impairs limb

function and activity level limited ligament surgery

LCL + PLC repair PCL avulsion

Physical Examination Isolated Ligament Exam

ACL Lachman @ 30°

PCL Posterior drawer @ 90°

LCL/PLC Varus stress @ 30° and full extension Tibial E.R. @ 30° Posterior tibial translation @ 30°

MCL Valgus stress @ 30°

Patellar tendon

Physical Examination

Combined Ligament Exam LCL/PLC & Cruciate

Varus in full extension & 30° MCL & Cruciate (PCL)

Valgus in full extension & 30° PLC & PCL

Tibial E.R. @ 30° & 90° Posterior tibial translation @ 30° & 90°

Stability in full extension Excludes significant PCL or capsular injury

Associated Injuries: Polytrauma knee dislocation is a spectrum of injuries

simple low energy sports related isolated injury

complex high energy vehicular trauma associated extremity and multi-system injuries

important differences future functional activities ability to participated in rehabilitation program other systemic and/or physiologic factors?

Associated Injuries: PolytraumaMills WJ : Severe HO After High Energy Knee Dislocation: The

Predicitve Value of the Injury Severity Score; OTA 2001.

35 consecutive knee dislocations Harborview Medical Center associated injuries

23% popliteal artery 20% peroneal nerve

surgical treatment 29: open acute [< 4 weeks] 6: arthroscopic delayed [6 wk - 10 m] CPM and early motion as wound permitted

Associated Injuries: PolytraumaMills WJ : Severe HO After High Energy Knee Dislocation: The

Predicitve Value of the Injury Severity Score; OTA 2001.

heterotopic HO: 6 patients (17%) ISS = 26-50 GCS = 3T-15

no heterotopic HO: 29 patients (83%) ISS = 9-26 GCS = 10-15 (2 severe brain injury)

6 of 23 (26%) multiple injuries developed HO positive predicitve value ISS > 26 = 86%

Associated Injuries: PolytraumaMills WJ : Severe HO After High Energy Knee Dislocation: The

Predicitve Value of the Injury Severity Score; OTA 2001.

HO occurred only in open acute cases (6/29 = 20%) 14% major wound complications bi-crucite surgery = 100% HO range of motion

4 ankylosis + 2 less than 10 º arc 3 open release and excision of HO - unsuccessful

6 delayed arthroscopic with ISS < 20: no HO range of motion

flexion average: 129º 50% flexion contracture >5 º 2 manipulation / 1 open release

Associated Injuries: PolytraumaMills WJ : Severe HO After High Energy Knee Dislocation: The Predicitve

Value of the Injury Severity Score; OTA 2001.

what is an ISS >26? ISS = sum 3 highest AIS² non-lethal single system injury of greatest magnitude: ISS = 25 two system injury needed to obtain ISS > 26

conclusion multisystem trauma and early open surgery increase risk for HO and loss of

motion poor functional outcome - not correctable change in treatment protocol at Harborview

limited early surgery brace or external fixation delayed surgery

Imaging the Dislocated Knee Plain X-ray

MRI

Arteriogram

Venography

CT Scan

Bone Scan

Plain Radiographs

Views AP & lateral 45° oblique Patellar sunrise

Findings Obvious dislocation Irregular/asymmetric joint

space Lateral capsular sign (Segond) Avulsions Osteochondral defects

MRI indications: all knee dislocations and equivalents

valuable diagnostic tool pre-operative planning

identify ligament avulsions: femoral PCL MCL: injury location incision lateral structures: popliteus, LCL, biceps meniscal pathology

displaced in notch early surgery limited arthroscopy 2º extravasation

articular cartilage lesions

Early Management ofKnee Dislocations

Orthopedic Emergency!!! Assess Neurovascular Status Closed Reduction

“Dimple sign” = irreducible (posterlateral dislocation) If No Pulse s/p Reduction

Vascular exploration Knee Immobilizer vs. External Fixation

Technique of Closed Reduction Anterior

Traction & elevation of distal femur Posterior

Traction & extension of proximal tibia Lateral / Medial

Traction & translation Rotational

Traction & Derotation AVOID force applied against popliteal fossa

Irreducible Knee Dislocation

Posterolateral “Dimple Sign”

Puckering of anteromedial skin Buttonhole

Medial femoral condyle thru medial retinaculum / capsule

Watch Skin Necrosis Open Reduction Required

Initial Stabilization ofKnee Dislocations

Knee Immobilizer Offers stability

External Fixation Better for grossly unstable knee Protects vascular repair Skin care for open injuries

NO Casting

Treatment: General Considerations most authors recommend repair of the torn

structures non-operative treatment: “poor results” period of immobilization

shorter = improved motion + residual laxity longer = improved stability + limited motion

recent clinical series have reported “better” results with operative treatment

no prospective, controlled, randomized trials of comparable injuries

Treatment: General Considerations immobilization after operative treatment

permanent stiffness flexion contracture (loss of extension) decreased flexion

early ROM is absolutely essential stable ligament fixation cooperative reliable patient

once stiffness occurs it is very difficult to treat

A loose mobile knee is better than a stable stiff knee!!

Treatment: Recommendations view the injury in the context of the whole

patient individualized treatment multiple variables 4 “key issues” that influence decision making

Treatment: RecommendationsKEY ISSUES

1. Associated injuries vascular injury nerve injury multi trauma head injury poor soft tissue envelope

LIMITED SURGICAL INTERVENTION

Treatment: RecommendationsKEY ISSUES

2. Presence of ligament avulsions “simplified” surgical treatment re-attachment

EARLY OPEN SURGERY

Treatment: RecommendationsKEY ISSUES

3. Complete posterolateral corner disruption is best treated with early open repair

LATE RECONSTRUCTION DIFFICULT

Treatment:RecommendationsKEY ISSUES

4. Reconstitution of the PCL is important allows tibiofemoral positioning around which collateral and ACL surgery evolve ACL reconstruction prior to PCL is never

indicated

PCL IS THE CENTRAL PIVOT

Non-operative Treatment immobilization in extension for 6 weeks external fixation

“unstable” or subluxation in brace obese multi-trauma head injury vascular repair fasciotomy or open wounds

Non-operative Treatment removal of fixator under anesthesia arthroscopy

manipulation for flexion assessment of residual laxity

Results of Ligament Reconstruction

Shapiro and Freedman 1995 10 Knee Dislocations Tx: 7 Patients

Early, Open Allograft Recon of ACL/PCL

MCL/LCL/PLC 1 repaired at time of OR

Average f/u 51 months Results:

6 patients good-excellent 4 of 7 needed manipulation

Fanelli et al 1996 20 Knee Dislocations Tx - Scope assist recon

ACL/PCL Allograft/autograft MCL tx non-op PLC tx w/biceps femoris Timing

PLC wait 2-3 weeks MCL 6 weeks rehab

Minimum f/u 2 years Results: knee scores, instability

Results of Ligament Reconstruction

Noyes & Barber-Westin 1997 11 Knee Dislocations Tx - Scope assist

Recon ACL/PCL Allograft/autograft Repair Medial/Lateral

Average f/u 4.8 years Immediate Motion Post-Op Results

5 required manipulation 9 patients full ROM 3 patients good-excellent

Wascher et al 1999 13 Knee Dislocations Tx

Allograft, Scope ACL/PCL recon Repair medial/lateral

Average f/u 38 months Results

Mean arc of motion 130 2 manipulations 1 knee “normal”, 6 sports

Results of Ligament Reconstruction

Yeh et al 1999 25 Knee Dislocations Tx - Scope

PCL recon / delay ACL 1 repair medial/lateral Timing 2 weeks

Average f/u 2 years Results

ROM 0 - 130 3 required scope debride 21 returned to office work

Cole and Harner 1999 25 Knee Dislocation Tx

Scope ACL/PCL recon 6 PLC recon / 7 MCL repair

Average f/u 3 years Results

5 lost 15 flexion 9 normal, 13 near normal KT-1000 = 0.1mm Timing w/in 3 wks preferred

Treatment of Specific Patterns

Treatment: KD-I

ACL + MCL MCL - predictable healing cylinder cast immobilization in extension for 2

weeks hinged brace ROM delayed ACL reconstruction

motion restored residual laxity and desired activity level

Treatment: KD-I

ACL + LCL/PLC delayed surgery @ 14

capsular healing identification of lateral structures

arthroscopic ACL - femoral fixation instruments and experience with open techniques femoral fixation tibial fixation / ACL tensioned after LCL/PLC

open posterolateral repair / reconstruction

Treatment: KD-II

ACL + PLC collateral ligaments intact

hinged brace + early ROM extension stop at 0º

arthroscopic reconstruction after 6 weeks PCL only in most cases ACL/PCL limited to high demand patient sedentary individuals = no surgery

Treatment:KD-IIIM

ACL + PLC + MCL immobilization in extension early surgery (2 weeks)

EUA and limited diagnostic arthroscopy (MRI) single straight medial parapatellar incision open PCL reconstruction or repair MCL repair

Case Example: KD-IIIM 47 year old female pedestrian MVA isolated injury examination

diffuse swelling and ecchymosis ROM: 10/0/80 normal DP/PT pulses motor sensory normal ligament testing

Lachman 3+post drawer 3+valgus 3+ 0º and 30ºvarus stable

Case Example: KD-IIIM closed reduction and brace arteriogram normal MRI

mid-substance ACL and PCL midsubstance MCL

EUA and stress radiographs

Case Example: KD-IIIM diagnostic arthroscopy

Case Example: KD-IIIM

Case Example: KD-IIIM

Case Example: KD-IIIM

Case Example: KD-IIIM

PCL Reconstruction: “Double Bundle”

Treatment: KD-IIIL ACL + PLC + LCL/PLC immobilization in extension delayed surgery @ 14 days

diagnostic arthroscopy arthroscopic or open PCL open LCL/PLC

incisions are critical - avoid midline PCL = medial (open or arthroscopic) straight posterolateral

42 female unrestrained front seat passenger MVA multiple injuries

laparotomy spleenectomy, hepatic packing LC-1 pelvis [R] knee dislocation

Case Example: KD-IIIL

knee examinationLachman 3+posterior drawer 3+valgus stablevarus 3+ @ 0º and 30 ºER all degrees

radiographs normal arteriogram normal immobilized in extension x 2 weeks

Case Example: KD-IIIL

Case Example: KD-IIIL

lateral exposure anatomic repair

ITB biceps femoris popliteus

tibial fibular

LCL posterior capsule meniscus

Case Example: KD-IIIL

Case Example: KD-IIIL

Case Example: PCL Femoral “Peel-Off”

Case Example: KD-IIILC 25 year old male motorcycle vs. telephone pole scene:

deformity knee confused and combative intubated and sedated

ground ambulance to local ER knee dislocation reduced abnormal vascular exam

Medflight to BMC

Case Example: KD-IIILC examination 3 hours after injury

effusion: none?swelling: severe, diffuse, ecchymosistenderness: sedatedROM: 15/0/120neurovascular: absent DP/PT pulses

cool pale footmotor / sensory NA

Case Example: KD-IIILC stability examination after injury

Lachman 3+posterior drawer 3+valgus stablevarus 3+ @ 0º and 30 ºER all degrees

isolated injury immediate treatment

4 compartment fasciotomy “on table” arteriogram in OR vascular reconstitution with RSV open lateral repair

Case Example: KD-IIILC

Case Example: KD-IIILC

Results of Ligament Reconstruction

Noyes & Barber-Westin 1997 11 Knee Dislocations Tx - Scope assist

Recon ACL/PCL Allograft/autograft Repair Medial/Lateral

Average f/u 4.8 years Immediate Motion Post-Op Results

5 required manipulation 9 patients full ROM 3 patients good-excellent

Wascher et al 1999 13 Knee Dislocations Tx

Allograft, Scope ACL/PCL recon Repair medial/lateral

Average f/u 38 months Results

Mean arc of motion 130 2 manipulations 1 knee “normal”, 6 sports

Results of Ligament Reconstruction

Yeh et al 1999 25 Knee Dislocations Tx - Scope

PCL recon / delay ACL 1 repair medial/lateral Timing 2 weeks

Average f/u 2 years Results

ROM 0 - 130 3 required scope debride 21 returned to office work

Cole and Harner 1999 25 Knee Dislocation Tx

Scope ACL/PCL recon 6 PLC recon / 7 MCL repair

Average f/u 3 years Results

5 lost 15 flexion 9 normal, 13 near normal KT-1000 = 0.1mm Timing w/in 3 wks preferred

Management of Nerve Injury

Exploration vs. Observation Early AFO Early Achilles Stretching Wait on Nerve Conduction Studies

At least 6 weeks, possibly 3 months Dynamic Bracing

i.e. articulating AFO Tendon Transfers PRN

Management of Nerve Injury

Surgical Exploration Intact BUT damaged

Observation 1 year or more until return 50% never return

Disruption Primary repair Cable grafting Results

– No good studies to date

Knee Dislocation: Summary anatomic classification selective use of angiography individualized surgical treatment

associated injuries limited surgery “corner repair”

multi-trauma head injury vascular or nerve injury

PCL + collateral

LOOSE AND MOBILE IS BETTER THAN STIFF AND STABLE

Return to Lower Extremity

Index