Transcript Posterolateral Rotatory Instability of the Knee

Posterolateral Rotatory
Instability of the Knee
Steven A. Seeker, M.D.
Objectives
 Define
posterolateral rotatory instability
of the knee
 Evolution of the human knee
 Anatomy and biomechanics of the
posterolateral corner
 Clinical presentation and treatment
options for acute and chronic instability
of the posterolateral corner of the knee
Definition
 Hughston
et al. JBJS 1976
 Posterior subluxation of the lateral tibial
plateau that can occur with an external
rotation torque in knees with pathologic
laxity of the posterolateral corner
 Symptoms can occur acutely after
violent injury or develop insidiously after
relatively mild injury
Evolution of human knee

Complex anatomy due
to evolution
 Early on, both the tibia
and fibula articulated
with the femur
 As the human knee
evolved, the fibula and
attached capsule
moved distally
Evolution of human knee

The popliteus
attachment moved
from the fibular head
to the femur creating
an intra-articular
portion
 Biceps attachment
moved from the
capsule and tibia to
the fibula
Posterolateral corner
“
Dark side of the knee “Andrews 1988
 Varying anatomy and inconsistent
terminology of the popliteofibular
ligament
Anatomy of the posterolateral
corner
 Three
distinct layers
Anatomy of the posterolateral
corner
First layer

Iliotibial tract
attaching to the tibia
at Gerdy’s tubercle

Biceps femoris
attaching to the fibular
head
Second layer

Quadriceps
retinaculum anteriorly

Patellofemoral and
patellomeniscal
ligaments posteriorly
Third layer

Superficial lamina:
Lateral collateral
ligament
Fabellofibular
ligament
Third layer

Superficial lamina:
Lateral collateral
ligament
Fabellofibular
ligament
Third layer

Deep lamina:
Coronary ligament
and popliteal hiatus
Popliteus
Arcuate ligament
Popliteofibular
ligament
Oblique popliteal
ligament
Third layer

Deep lamina:
Coronary ligament
and popliteal hiatus
Arcuate ligament
Popliteofibular
ligament
Oblique popliteal
ligament
Variable anatomy
 Seebacher
et al. JBJS 1982
 35 cadaver knees
 Conclusions:
arcuate ligament alone in 13%
fabellofibular ligament alone in 20%
both in 67%
no mention of popliteofibular ligament
Variable anatomy
 Sudasna
and Harnsiriwattanagit 1990
 Dissection of fifty cadaver knees
 Conclusions:
“Fibular origin of the popliteus”
(Popliteofibular ligament) in 98%
Fabellofibular ligament in 68%
Arcuate ligament in 24%
Variable anatomy
 Watanabe
et al. arthroscopy 1993
 115 cadaver dissections
 Conclusions:
lateral collateral and popliteus present
in all knees
“popliteus muscle with origin from the
fibular head” (popliteofibular ligament)
present in 94% of knees
Popliteofibular ligament (PFL)

Oversight in anatomy texts
resulted in disappearance of
this structure until only
recently

Maynard et al. Am J Sports
Med 1996 reported on the
“rediscovery of the PFL”
Popliteofibular ligament (PFL)

This appears to be an
important static stabilizer of
the posterolateral corner
Popliteofibular ligament (PFL)
 Maynard
et al. Am J Sports Med 1996
 Cross sectional area of PFL only slightly
less than FCL
 Maximal force to failure PFL (425 N)
FCL (747 N)
Popliteofibular ligament (PFL)
 Veltri
et al. Am J Sports Med 1996
 PFL and
popliteus were important in
resisting posterior translation, primary
varus rotation, and external rotation
Blood supply

Popliteal artery

Genicular arteries
Review of anatomy
 Three
 First
layers of the posterolateral corner
layer are dynamic stabilizers
 Second
layer relatively unimportant
Review of anatomy
 Third
layer: static stabilizers and most
important layer
FCL and popliteus are always present
PFL present in majority of knees
arcuate and fabellofibular ligaments are
variable
coronary ligaments are very loose to
allow for very mobile lateral meniscus
Biomechanics
Biomechanics

Nielson et al. Arch Orthop Trauma Surg
1984, 1985
 Lateral collateral and posterolateral capsule
resist varus and external rotation of the tibia
 Popliteus resists varus from 0-900 and resists
external rotation from 20-1300 of flexion
 PLC also is a secondary restraint to posterior
translation, but isolated sectioning of the PCL
does not affect varus or external rotation
Biomechanics

Gollehon et al. JBJS 1987
 PCL resists posterior translation
 Sectioning of PLC/FCL causes the greatest
increase in varus and external rotation at 30o
of flexion
 Additional sectioning of PCL causes greater
increase in varus and external rotation
 ACL/PLC sectioning causes tibial internal
rotation and anterior translation to be
increased at 30o and 60o
 ACL or PLC sectioning alone does not
increase tibial internal rotation
Biomechanics
 Markolf
et al. JBJS 1993
 Sectioning
of PLC significantly
increases the force on the PCL between
45o and 90o of flexion
 Sectioning of PLC increases mean force
on ACL at all flexion angles
Biomechanics
 Noyes
et al. Am J Sports Med 1993
 Sectioning PLC increases lateral tibial
plateau posterior translation at 30o but
not at 90o
 Sectioning of PLC and PCL increases
posterior subluxation of both plateaus at
both 30o and 90o
Biomechanics
 LaPrade
et al. Am J Sports Med 1999
 Forces in ACL grafts when the
posterolateral corner had been
sectioned were increased with coupled
varus and external rotation at 0o and 30o
of flexion
Biomechanics
 Skyhar
et al. JBJS 1993
 Ten cadaver knees
 Combined sectioning of PLC and PCL
resulted in significantly more
patellofemoral contact force than
sectioning of the PCL alone
Biomechanics
 Summary:
 Isolated
PCL tear does not increase
primary varus or external rotation
 Isolated FCL tear causes a mild
increase in varus angulation which is
greatest at 30o of flexion
 Injury of PLC with intact PCL results in
maximal increase of varus, external
rotation and posterior translation at 30o
of flexion
Biomechanics
 Summary:
at 90o, the PCL fibers become
tight and exert a secondary constraint
on varus and external rotation
 PCL and PLC complete injury cause
increased varus, external rotation and
posterior translation at all flexion angles
 Cruciate ligament grafts are at
increased risk of failure in knees with
posterolateral rotatory instability
 However,
Examination of the
posterolateral corner
 History
and physical exam
special tests
 Radiographic evaluation
 Magnetic resonance imaging
 Arthroscopic evaluation
History
 Pain
in posterolateral knee
 Peroneal nerve symptoms?
 May have medial or lateral joint line pain
 Instability with knee in extension
Physical examination
 Edema,
ecchymosis, induration and
tenderness
 Full ligament exam and neurovascular
exam in all patients
 May have standing varus alignment or a
varus thrust with walking
 May walk a flexed knee due to pain and
instability with knee hyperextension
Special tests
 Posterior
drawer
 Tibial external rotation (dial) test
 Posterolateral external rotation test
 Reverse pivot shift test
 External rotation recurvatum test
Posterior drawer
Performed at 30o and
90o
 Laxity at 30o indicates
PLC injury
 Laxity at 90o indicates
PCL injury
 May appear like an
ACL injury, but tibia is
posterior and ACL
endpoint is good

Tibial external rotation (dial)
test

Performed while
prone at 30o and 90o
 PLC only:
increased at 30o
only
 PCL only:
no side to side
difference
 PCL and PLC:
increased at 30o and
90o
Posterolateral external
rotation test
Performed at 30o
and 90o with coupled
posterior and
external rotation
force
 Similar results to
drawer and dial
tests

Reverse pivot shift test

Sensation of
reduction when the
flexed, externally
rotated tibia
knee is extended
with a valgus
applied force
 May be positive in
up to 35% of normal
knees during EUA
 May be PLC or PCL
injury
External rotation recurvatum
test

Elevation of lower
extremity by great
toe results in
hyperextension,
varus and external
rotation
PCL vs. PLC vs. Both
Radiographic evaluation

Plain film
radiographs may
show avulsion
fractures, widened
lateral joint line
Segond fracture
(lateral capsular
sign may be
present)
Magnetic resonance imaging

Yu et al. Radiology
1996
 T2 weighted coronal
oblique MRI give
best resolution of
PLC
 LaPrade et al. Am J
Sports Med 2000
 Developed protocol
for PLC imaging
Arthroscopy

Valuable to evaluate
popliteus and
meniscus, as well as
articular surface
injuries prior to open
repair
 “Drive through sign”
 Caution:
fluid extravasation
Grading of injury
1: no abnormal motion with 0 –
5mm of joint opening, and definite end
point
 Grade 2: slight to moderate abnormal
joint motion with 6 – 10 mm joint
opening, and definite end point
 Grade 3: markedly abnormal joint
motion with greater than 10 mm joint
opening, and no endpoint
 Grade
Grading of injury
 Kannus
Am J Sports Med 1989
 23 patients with grade 2 and 3 injuries
treated non-operatively
 8 year follow-up
 11 patients with grade 2 lesions
excellent or good knee scores, 9 were
asymptomatic, all had residual laxity, no
DJD
 12 patients with grade 3 lesions fair or
poor knee scores, but not all isolated
PLC injury, DJD in 6 patients
Treatment
 Non-operative
treatment
 Operative treatment
1. Acute injury
2. Chronic instability
Non-operative treatment
 Isolated
posterolateral corner injuries
are treated with a hinged knee brace to
prevent varus and external rotation
 The literature supports non-operative
management of all grade 1 and 2
isolated PLC injuries
 However, may consider operative
management of grade 2 lesion if
cruciate reconstruction is planned
Operative treatment
 Acute
injury:
Direct repair within 3 weeks to avoid
“matted mess” has best outcome
+/- augmentation
 Chronic instability:
Reconstruction
Surgical approach

Incision
Surgical approach

Internervous plane:
between ITB and BF
 May osteotomize
Gerdy’s tubercle for
better visualization
 Must see the
common peroneal
nerve
Direct repair

Skin incision often is
the only dissection
needed in acute
injuries
 Repair deep
structures first,
followed by
superficial structures
Direct repair

May need to
augment structures
with autograft or
allograft if structures
are not repairable
 Combination of
techniques used to
repair all structures
Order of evaluation / repair
 Coronary
ligament: evaluate for tears or
avulsion from tibia – fix with sutures or
anchors
 Popliteus and popliteofibular ligaments:
fix with anchors or pull-out sutures if
avulsed or Kessler sutures if torn
 FCL: sutures or anchors
 Arcuate and fabellofibular ligaments:
variable, but should be repaired if torn
or avulsed
Reconstruction of chronic
instability
 Often
needed after grade 3 injuries
treated non-operatively
 Surgical dissection more difficult
secondary to scar
 Goals: restore function and stability to
the knee
Special considerations for
reconstruction

Alignment: full
length x-rays of
lower extremity to
evaluate
 Varus with lateral
thrust: HTO prior to
reconstruction of
posterolateral
structures or repair
will stretch out
High tibial osteotomy

Not like HTO for
DJD
 Long lateral incision
centered over ITB
 Gerdy’s tubercle
advanced with bone
plug
 Avoid disruption of
proximal tib-fib joint,
as this will worsen
PLC symptoms
High tibial osteotomy
Gerdy’s fixed with
6.5mm screw
 Osteotomy fixed
with staples
 Fibular osteotomy
should be performed
at the mid fibula
level
 Reassess PLC at 6
months, symptoms
may resolve with realignment

High tibial osteotomy
 Alternatively,
a medial opening wedge
osteotomy of the proximal tibia can be
performed
 Advantages: avoids the proximal tib / fib
joint and posterolateral structures
 Disadvantages: 2 surfaces to heal
+/- use of allograft or ICBG
Posterolateral corner
reconstruction
Advancement of femoral
attachment of FCL and PT
Hughston and Jacobson

Advancement of FCL /
popliteus and lateral
gastroc origin with
suturing of FCL to
gastroc
 96 knees
follow-up 4 years
85% objectively good
78% subjectively good
80% functionally good
Advancement of femoral
attachment of FCL and PT
Hughston and Jacobson

Advancement fixed
with knee at 90o
 Criticized because it
does not address
PFL or popliteus
musculotendinous
junction
Advancement of femoral
attachment of FCL and PT
Hughston and Jacobson

Knee is placed in a
controlled motion
brace with 45 degree
extension block
 Flexion is encouraged
to prevent
patellofemoral
problems
Biceps tenodesis
(Clancy and Sutherland)

Anchor the biceps to
the lateral femoral
condyle to reduce the
deforming force in
external rotation and to
recreate the FCL
 39 patients, average
follow-up of 32 months
77% no ADL restriction
54% return to sports
Biceps tenodesis
(Clancy and Sutherland)

Wascher Am J Sports
Med 1993
biomechanical study
showed that this was
effective, but it
overconstrained the
joint
 Veltri et al. Am J
Sports Med 1996
this does not address
the popliteus or PFL
Biceps tenodesis
(Clancy and Sutherland)

Many authors have
been reluctant to
attempt this because
of the difficulty in
salvaging the knee if
this fails
Recession of PT and FCL
(Jakob and Warner)

When the popliteus
and FCL are
stretched, but intact,
the femoral
attachment may be
recessed and fixed by
a screw / washer
 Advantage is isometric
placement
Recession of PT and FCL
(Jakob and Warner)

If the PFL is intact,
this procedure
should tighten this
structure as well
Posterolateral corner sling
(Albright and Brown)

Uses autograft or
allograft to recreate the
static effect of the
popliteus
 Central third of the ITB
is harvested and left
attached to Gerdy’s
tubercle
 Tunnel drilled through
lateral tibia to the point
of normal popliteus
passage on the
posterior lateral plateau
Posterolateral corner sling
(Albright and Brown)

Graft is fixed just
proximal to the origin of
the FCL
 30 patients
8 excellent (no joint
pathology)
10 poor (joint pathology
or instability)
6 additional procedures
 Does not address PFL
or FCL
Anatomic reconstruction of PT
and/or PFL and/or FCL
(Veltri and Warren)

Suggested anatomic
reconstruction of all
injured / attenuated
structures
 Popliteus: reconstruct
with allograft (achilles)
similar to Albright’s
procedure
fix with suture and
buttons or interference
screws
Anatomic reconstruction of PT
and/or PFL and/or FCL
(Veltri and Warren)

Popliteofibular ligament:
similar, but tunnel drilled
through fibula to recreate
origin of PFL ligament
fixed to lateral epicondyle
just proximal to FCL origin
secured with buttons or
interference screws
Anatomic reconstruction of PT
and/or PFL and/or FCL
(Veltri and Warren)

Popliteus and PFL:
combine both
reconstructions with
a single split achilles
allograft with bone
end of the graft
secured to the femur
Anatomic reconstruction of PT
and/or PFL and/or FCL
(Veltri and Warren)

Popliteus, PFL and
FCL: If FCL also
requires reconstruction,
use distally based
segment of the biceps
femoris with fixation to
the epicondyle with
screw and soft tissue
washer
Anatomic reconstruction of PT
and/or PFL and/or FCL
(Veltri and Warren)

Patient is placed in
a hinged knee brace
to prevent varus and
external rotation
 Toe touch weightbearing with brace
locked in extension
 Allowed motion
when NWB
Anatomic reconstruction of PT
and/or PFL and/or FCL
(Veltri and Warren)

Bike at 4 weeks
 Closed chain at 6
weeks
 Jogging at 4 months
 Brace worn for 6
months
 Return to sports at
6-9 months
Anatomic reconstruction of PT
and/or PFL and/or FCL
(Veltri and Warren)

This technique is
relatively new and
there are no long
term follow-up
studies
 Promising because
of anatomic
reconstruction of
injured structures
Order of repair of the multiply
ligamentously injured knee
 Most
authors at the recent AAOS
suggested fixing the PLC prior to ACL or
PCL repair
 If all three are injured, fix the PLC first at
300, followed by the PCL
 ACL may be fixed at a later date
Review of Posterolateral
corner
 Anatomy
is variable, but the FCL,
popliteus and popliteofibular ligaments
are present in most knees
 Careful physical examination of all
ligaments will allow the diagnosis of
injury to the PLC
 PLC laxity is greatest at 30o of knee
flexion
 Arthroscopy and MRI are useful
adjuncts to physical exam
Review of Posterolateral
corner
 Grade
1 and 2 isolated lesions can be
treated conservatively
 Grade 3 lesions should be treated
operatively
 Early operative intervention has the best
chance of a good result
 Late reconstruction is a salvage
procedure
 Prognosis is related to other related
pathology (ie. DJD, meniscus tear, etc.)
Review of Posterolateral
corner
 Multiple
methods of reconstruction are
available
 Anatomic reconstruction is a promising
new method of reconstruction, but
follow-up studies are not yet available