Posterior cruciate ligament (PCL) tears
comprise 3% of outpatient knee injuries and
38% of acute traumatic knee hemarthroses
These injuries rarely occur in isolation, and
up to 95% of PCL tears occur in combination
with other ligament injuries
Anatomy of PCL
Mechanism of Injury
Clinical Evaluation
Investigations
Management
Tibial footprint is located
between the posterior horns of
two menisci about 1–1.5 cm
below the posterior tibial
margin in the ‘PCL facet’
AL and PL fibers further extend
upward and medially to be
attached onto the medial
femoral condyle.
ALB is attached mostly to the
roof of the intercondylar notch
and PLB to the medial side of the
wall
More Important
in Extension of
the knee
More Important in
Flexion of the knee
The PCL is also strengthened
by the meniscofemoral
ligaments (MFL), anteriorly
(ligament of Humphrey) and
posteriorly (ligament of
Wrisberg).
Tensile loads are in the range of 2k to 3kN
38 mm in length x 13 mm in diameter
Diameter is 1.3 times larger than the ACL
Restrains posterior tibial translation as the
knee moves from extension to flexion
throughout the arc of motion (0–120°)
especially from 30°–90° flexion
Posteromedial, posterolateral capsule and
collaterals aid in the posterior restraint
between 0° and 30° flexion
Covey et al. demonstrated that Posterior
translation of tibia increases by two fold (7.23
± 0.65 mm) at 90° flexion as compared with
20° flexion (3.41 ± 0.77 mm) at 74 N
posteriorly directed force over tibia after
selective sectioning of the PCL
The role the PCL plays in the rotational control of the knee
is still unclear, with many contradictory studies published
in the literature
It restricts internal rotation at all flexion angles, PMB
particularly was reported to be controlling rotation beyond
90º of flexion
It acts as a secondary stabilizer to rotational forces when
other ligaments are compromised and other ligaments may
provide control to rotation when the PCL is deficient
The deficiency of the PCL results in
increased joint contact pressures in the
medial and patellofemoral compartments
Untreated PCL deficiency have greater
incidence of medial and patellofemoral
compartment degeneration
Results showed significant posterior
subluxation of the tibia at 60° of flexion in the
PCL-deficient specimen, which resulted in
increased contact pressure and pressure
concentration in the medial compartment
Direct blow to proximal tibia with a flexed knee
(dashboard injury)
Hyperflexion with a plantar-flexed foot
Hyperextension injury
External rotation force on a weightbearing leg
with the knee in near full extension
History
Physical Examination
Exploring the mechanism of injury
Energy or velocity imparted to the knee
during the injury
Did the knee swell up immediately?
Could the patient bear weight? Did the knee
feel unstable?
Current symptoms including pain, stiffness,
instability
Look
Feel
Move
Posterior drawer test
Posterior sag test (godfrey test)
Quadriceps active test
Dial test
Varus/valgus stress
Performed at 90º of knee flexion, and has a
sensitivity of 90% and a specificity of 99%
Isolated PCL translate >10-12mm in neutral
and >6-8mm in internal rotation.
Combined ligamentous injuries translate
> 15mm in neutral and >10mm in internal
rotation.
A standard knee series, including
bilateral standing (AP),
AP flexion 45° weight bearing
Lateral and
Merchant patellar radiographs
should be evaluated for any evidence of avulsion
fractures, tibial subluxation and associated knee
injuries and chronic cartilage damage
Stress radiography has been gaining
popularity for the diagnosis of multi-
ligamentous knee injuries
It involves the application of a standardized
force to the knee to produce abnormal joint
displacement
Several techniques have been described
including hamstring contraction, gravity
assisted, the Telos device and single-leg
kneeling
The Telos device and kneeling have been
shown to be superior to other methods for
reproducibly demonstrating posterior knee
instability
A diagnostic algorithm has been validated where
side to side posterior translation difference has
been quantified
1. 0–7 mm = a partial PCL tear
2. 8–11 mm = isolated complete PCL tear
3. ≥12 mm = combined PCL and posterolateral
corner or posteromedial corner knee injury
High sensitivity (near 100%) and specificity (near
97%)
MRI is the radiologic study of choice in
diagnosing acute PCL tears, Although chronic
PCL injuries may be apparent on MRI it is not as
sensitive in diagnosing chronic tears
MRI may appear normal as soon as 3 months
following low-to moderate-grade PCL injuries
Normal PCL is homogeneously low signal on both
T2 and proton density weighted sequences,
lacking internal striations like ACL.
Normal PCL should measure 6 mm or less, when
measured from anterior to posterior in the
sagittal plane
There are two potential pitfalls if one relies
only on the sagittal plane
First, partial tears may be interpreted as
complete tears.
Second, mucoid degeneration may mimic a
PCL tear in the setting of a functionally stable
ligament
Nonoperative vs operative
Repair vs reconstruction
Autograft vs allograft
Single vs double bundle
Arthroscopic vs Open technique
Rehabilitation
Acute Isolated grade I and Grade II tears (posterior
tibal translation < 10mm)
Asymptomatic patients
Knee should be immobilized for 2-4weeks
Functional dynamic force braces have been designed
to keep the knee in anterior drawer to avoid laxity
during healing
Strengthening of quadriceps and avoiding hamstrings
use
Grade III injuries with >10 mm of posterior
tibial displacement
Symptomatic complete tears
PCL tears with other ligamentous injuries
(ACL, MCL, PLC)
Acute bony avulsion injuries of the PCL
attachment
Failure of conservative management
Long-term subjective evaluations of patients are very
comparable
At a mean of 17 years after non operative treatment,
Shelbourne et al. found a mean IKDC score of 73,
which compares to IKDC scores of 65 found by 2
nd
study of operative treatment that had much less
follow-up times of 9–10 years
Arthroscopic primary PCL repair with suture
augmentation can be performed in patients
with proximal soft tissue avulsion tears
Ligament remnants that can be re
approximated to the femoral wall and have
sufficient tissue quality to withhold sutures
can be primarily repaired rest needs
reconstruction
Eliminates donor-site morbidity
Multiple ligament injuries in which multiple
grafts will be required
Meta-analysis shows that the clinical
outcomes were similar between allograft
and autograft tendons for PCL
reconstruction
Theoretically has the advantages of availability,
consistency, and appropriate mechanical strength, no
donor site morbidity and no risk of disease transmission
Eg. Carbon fiber, dacron, bundled
polytetrafluoroethylene (GORE-TEX™), ABC carbon,
polyester
Longer term follow-up demonstrated recurrent
instability and chronic effusions hence their use is
controversial
Only AL bundle is reconstructed during
single-bundle PCL reconstruction
One femoral tunnel is made
Both auto and allografts can be used
Both ALB and PMB are reconstructed in
Double bundle PCLR
Theoretically it restore the normal
kinematics
It requires two separate femoral tunnels to
reconstruct ALB and PMB that puts femur at
risk for MFC fractures.
This systematic review found that double-
bundle reconstruction was superior to
single-bundle in biomechanical studies BUT
clinical outcomes showed no significant
differences between the two PCL
reconstruction techniques
Preferred technique is a single AL
bundle reconstruction because it
reduces surgery time and clinical
evidence demonstrates no advantage
Aims to simulate the tibial and femoral ALB
origins
Incase of DB PCLR a 5-mm bone bridge is
maintained between femoral tunnels
The main concern in this technique is the so-
called ‘killer turn’, the sharp angle on the tibial
tunnel exit that may produce abrasion,
attenuation and subsequent graft failure
Proximity of neurovascular structures to the PCL
insertion is another challenge. The anterior wall
of the popliteal artery lies approximately 7–10
mm from the posterior border of the PCL at 90°
of flexion
If only ALB is reconstructed the graft is
tensioned between 70°-90° of knee flexion
For Double bundle PMB is tensioned is full
knee extension
The two strongest advantages of tibial inlay
technique are its secure bone-to-bone
fixation on the tibia, and the elimination of
the “killer turn”
Both open and arthroscopic techniques are in
practice
Phase I ( 0 – 6 weeks)
Phase II (6weeks – 6 months)
Phase III (6 Months – 12 Months)
1
st
4 weeks= brace locked in full extension, passive ROM
up to 90° flexion, NWB with crutches
After 4 weeks= brace unlocked to 100°, passive ROM
beyond 90°,weight bearing as tolerated with crutches
and brace on
Quad sets ,Straight leg raise (SLR) with brace locked,
Ankle DF and PF, avoid active contraction of hamstrings
Patella mobilization
Discontinue brace and crutches at 6 weeks
Passive stretching
Closed chain exercises as tolerated
Maximum knee flexion: 10–15° terminal
flexion deficit is not unusual
Quadriceps strength 80–90 % of the
contralateral limb
Quadriceps symmetry
Open and closed chain exercises as tolerated
Return to sport-specific activity as tolerated
They found the overall complication
rate for arthroscopic knee surgery was
4.7 %; however, 20.1 % of PCL
reconstructions had a complication
Neurovascular injury
Loss of flexion ( 10-20 degrees)
Failure to obtain objective stability
Osteonecrosis of the medial femoral condyle