orthopaedics and trauma

1. Knee Dislocation
William R. Creevy, MS, MD
Assistant Professor and Vice Chairman
Department of Orthopaedic Surgery
Boston University Medical Center
Mark A. Neault, MD
Brian D. Busconi, MD
University of Massachusetts Medical School

2. 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

3. 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

4. Epidemiology
true incidence is probably underreported
20% - 50% spontaneously reduced
practice environment
trauma center
sports medicine practice
general orthopaedics

5. Anatomy
4 ligament structures
ACL
PCL
MCL
PLC
LCL
popliteus
biceps femoris
ITB

6. Anatomy
popliteal artery
adductor hiatus
soleus arch
tension injury
hyperextension
posterior

7. Anatomy
peroneal nerve
biceps femoris
fibular neck
tension
varus
direct injury

8. 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

9. Pathomechanics
Kennedy, 1963
10 cadaveric knee specimens
hyperextension
ACL
PCL
posterior capsule @ 30º
popliteal artery @ 50º

10. 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

11. Classification
purpose
determine prognosis (outcome)
guide treatment
historical: Kennedy (1963)
tibial position with respect to femur
visual inspection
radiograhs
documented dislocation
both cruciates torn

12. 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)

13. 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 + collateral
ACL + collateral
PCL + collateral
ACL / PCL collaterals intact

14. 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

15. 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

16. 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?

17. 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

18. 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

19. 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

20. 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?

21. Vascular Injuries: Principles
1. 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.

22. Vascular Injuries: Principles
5. 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.

23. 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

24. 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

25. 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)

26. Case Example: KD-IIIM

27. 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

28. 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?

29. 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

30. 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

31. 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

32. 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?

33. Associated Injuries: Polytrauma
Mills 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

34. Associated Injuries: Polytrauma
Mills 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%

35. Associated Injuries: Polytrauma
Mills 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

36. Associated Injuries: Polytrauma
Mills 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

37. Imaging the Dislocated Knee
Plain X-ray
MRI
Arteriogram
Venography
CT Scan
Bone Scan

38. Plain Radiographs
Views
AP & lateral
45° oblique
Patellar sunrise
Findings
Obvious dislocation
Irregular/asymmetric joint
space
Lateral capsular sign (Segond)
Avulsions
Osteochondral defects

39. 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

40. Early Management of
Knee 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

41. 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

42. Irreducible Knee Dislocation
Posterolateral
“Dimple Sign”
Puckering of anteromedial skin
Buttonhole
Medial femoral condyle thru medial retinaculum /
capsule
Watch Skin Necrosis
Open Reduction Required

43. Initial Stabilization of
Knee Dislocations
Knee Immobilizer
Offers stability
External Fixation
Better for grossly unstable knee
Protects vascular repair
Skin care for open injuries
NO Casting

44. 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

45. 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!!

46. Treatment: Recommendations
view the injury in the context of the whole
patient
individualized treatment
multiple variables
4 “key issues” that influence decision making

47. Treatment: Recommendations
KEY ISSUES
1. Associated injuries
vascular injury
nerve injury
multi trauma
head injury
poor soft tissue envelope
LIMITED SURGICAL INTERVENTION

48. Treatment: Recommendations
KEY ISSUES
2. Presence of ligament avulsions
“simplified” surgical treatment
re-attachment
EARLY OPEN SURGERY

49. Treatment: Recommendations
KEY ISSUES
3. Complete posterolateral corner disruption is
best treated with early open repair
LATE RECONSTRUCTION DIFFICULT

50. Treatment:Recommendations
KEY 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

51. 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

52. Non-operative Treatment
removal of fixator under anesthesia
arthroscopy
manipulation for flexion
assessment of residual laxity

53. 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

54. 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

55. 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

56. Treatment of Specific Patterns

57. 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

58. 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

59. 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

60. 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

61. 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 30º
varus stable

62. Case Example: KD-IIIM
closed reduction and brace
arteriogram normal
MRI
mid-substance ACL and PCL
midsubstance MCL
EUA and stress radiographs

63. Case Example: KD-IIIM
diagnostic arthroscopy

64. Case Example: KD-IIIM

65. Case Example: KD-IIIM

66. Case Example: KD-IIIM

67. Case Example: KD-IIIM

68. PCL Reconstruction: “Double Bundle”

69. 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

70. 42 female
unrestrained front seat passenger MVA
multiple injuries
laparotomy
spleenectomy, hepatic packing
LC-1 pelvis
[R] knee dislocation
Case Example: KD-IIIL

71. knee examination
Lachman 3+
posterior drawer 3+
valgus stable
varus 3+ @ 0º and 30 º
ER ↑ all degrees
radiographs normal
arteriogram normal
immobilized in extension x 2 weeks
Case Example: KD-IIIL

72. Case Example: KD-IIIL

73. lateral exposure
anatomic repair
ITB
biceps femoris
popliteus
tibial
fibular
LCL
posterior capsule
meniscus
Case Example: KD-IIIL

74. Case Example: KD-IIIL

75. Case Example: PCL Femoral “Peel-Off”

76. 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

77. Case Example: KD-IIILC
examination 3 hours after injury
effusion: none?
swelling: severe, diffuse, ecchymosis
tenderness: sedated
ROM: 15/0/120
neurovascular: absent DP/PT pulses
cool pale foot
motor / sensory NA

78. Case Example: KD-IIILC
stability examination after injury
Lachman 3+
posterior drawer 3+
valgus stable
varus 3+ @ 0º and 30 º
ER ↑ all degrees
isolated injury
immediate treatment
4 compartment fasciotomy
“on table” arteriogram in OR
vascular reconstitution with RSV
open lateral repair

79. Case Example: KD-IIILC

80. Case Example: KD-IIILC

81. 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

82. 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

83. 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

84. 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

85. 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
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Lower Extremity
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