PCL, PLC, Knee Dislocation

POSTGRAD ORTH Deiary Kader

Postgraduate OrthpaedicsFRCS(Tr&Orth) Revision Course

Professor Deiary KaderConsultant Orthopaedic & Trauma Surgeon

Knee Surgeon

Newcastle Nuffield


PCL and PLC

Professor Deiary Kader

Consultant Orthopaedic & Trauma Surgeon

Knee Surgeon

Newcastle Nuffield Hospital


Classification of knee

Stabilizers

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Lateral Complex

IT Tract

LCL

Popliteus

Biceps Femoris

Central Complex

ACL

PCL

Med Menx

Lat Menx

Medial Complex

MCL

Postromedial

Capsule

Semi-Memb

Pes anserinus


Paul F. Segond

a Paris surgeon

1879

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PCLThe strongest ligament in the knee

It is regarded as “a central stabilizer”

Originates from a broad crescent-shaped area in the

posterolateral medial femoral condyle

Inserts centrally posteriorly 1–1.5cm below articular surface

of the tibia

Has an average length of 38 mm and diameter of 13 mm

PCL and quadriceps are dynamic partners in stabilizing the

knee in the sagittal plane6


PCLMechanism of Injury

RTA

– High Velocity

– Often MLI

Sports

Uncommon

– Low Velocity

– Usually Partial

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Mechanism of injury

3% of all knee injuries

Direct injury dashboard at 90 is the most common

Falling on a flexed knee with foot in plantar flexion

Forced hyperextension (>30º) is associated with multi-

ligament injury

High association with fracture femur


PCL Injury Diagnosis

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Physical Exam

– Posterior Drawer

– Step off sign

Plain Radiographs

– Look for bony avulsions

– Standing films for chronic injuries (Arthritis)

– Stress Radiographs helpful

MRI

– Not Sensitive

– MLI (common)


PCLThree components:

AL: Antero-lateral: long and thick part, twice the size

of the posteromedial bundle; tightens in flexion

PM: Posteromedial: tight in extension

Meniscofemoral ligaments: mechanically very strong

Anterior: Humphrey’s ligament

Posterior: Wrisberg’s ligament


Ant Meniscofemoral lig

Humphrey


a. Ant Meniscofemoral lig

Humphrey

b. Post Meniscofemoral lig

Wrisberg


ACL & PCL Recon


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Diagnosis 1

MRI & PCL

Clinical examination is more reliable than MRI

scan

The PCL may be dysfunctional despite normal MRI

Kneeling stress x-ray shows the degree of posterior

translation


Diagnosis 2Clinical

Posterior drawer test at 90 and 30

Quadriceps active drawer test. Flex the knee to 60 and

control the foot then ask the patient to contract the

quads. The test is positive when the tibia reduces.

Posterior sag sign (step-off)

Posterolateral rotatory instability (Dial test prone)

External rotation recurvatum test


Grading of PCL instability

Normal tibia step-off is 10 mm at 90 flexion

Instability could be mild, moderate or severe

Grade I instability is when there is a 5-mm step-off

Grade II instability is when there is no step-off (flush)

Grade III instability is when there is –5 mm step-off

There is a high association between Grade III PCL

injury and posterolateral corner injury.


Management

In isolation, it often causes little long-term

instability. However, it may lead to medial

or PFJ pain (OA) at a later date.

More troublesome in soccer players due to

difficulty in deceleration.


Management 2Presentation

Acute isolated PCL injury is commonly missed

Present with very little pain in the knee without hemarthrosis

There may be only bruising at the popliteal fossa.

Chronic PCL injury on the other hand may present with pain in

the medial compartment or anterior knee pain.


Treatment

Treat acute, isolated PCL injury conservatively.

Extension brace with calf support (Posterior Tibial Support,

PTS Brace) until the pain subsides (4-6 weeks) with quadriceps

rehabilitation

Start early passive motion only in prone position to maintain

anterior tibia translation.


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PCL Reconstruction


Surgical reconstruction

Indications

Acute combined injuries

Acute bony avulsion

Symptomatic chronic PCL injuries that failed rehabilitation.

There is no difference in clinical outcome between single and

double bundle PCL reconstruction.


Complications

Immediate

Neurovascular injury popliteal vessels

Infection

Technical error → tunnel placement, graft tensioning, insecure fixation

Delayed

Loss of motion

Avascular necrosis (medial femoral condyle)

Recurrent or persistent laxity (common) when a combined injury is not

adequately addressed


Posterolateral Complex

Components:

– Biceps, ITB, Popliteus,

Popliteofibular ligament, arcuate

ligament, LCL

Function

– Resists External and Varus rotation

Mechanism of Injury

– Direct blow to anteromedial tibia

– Hyperextension/varus

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arcuate


The Posterolateral Corner

The LCL is a cord like structure 5-7 cm in length

Is the primary static restraint to varus opening of the knee

Secondary restraint to posterolateral rotation

The popliteus is a static and dynamic external rotation stabiliser.

The popletiofibular ligament acts as

a primary restraint to external rotation of

the tibia on the femur at 30º of flexion

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The Posterolateral Corner

(PLC)They are the primary stabilisers of external tibial rotation at

all knee flexion angles and the secondary restraints to

anterior and posterior translation

Isolated PLC sectioning produce a maximal average increase of

13° of ER at 30° of knee flexion and only an average increase of

5.3° at 90°.

Isolated PCL sectioning has no effect on external tibial rotation

Combined injury to the PCL and PLC leads to ER of 20.9° at

90° of knee flexion26


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Fib

Pop

Extension

The popliteus tendon inserted

10 mm distal

5 mm posterior to the lateral epicondyle

The LCL inserted

1-2 mm proximal

4-5 mm posterior to the lateral epicondyle


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Fibula head


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Popliteofibular LIG


LCL Examination

Opening @ 30º only

– Isolated LCL Injury

Opening @ 0º

– Injury to Posterolateral Capsule (+ Dial)

– Usually with ACL +/or PCL injury

Palpate LCL in Figure 4 Position

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ImagingPlain Films

– Check for Biceps/LCL Avulsion fracture

MRI

– Can be helpful

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Injury--TreatmentPartial

– Grade I & II Instability with a good end

point

– Nonsurgical Treatment

– 3 week immobilization in extension

Complete Acute

– Primary repair best

– Augment with allo/auto graft

Complete Chronic

– Reconstruct Popliteus and LCL

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InjuryPhysical Examination

– Dial Test

• Increased External

rotation (30o, 90o)

– Posterolateral external

rotation test

– External rotation

recurvatum34



Injury--TreatmentPartial

– Grade I & II Instability with a good end point

– Nonsurgical Treatment

– 3 week immobilization in extension

Complete Acute

– Primary repair best

– Augment with allo/auto graft

Complete Chronic

– Reconstruct Popliteus and LCL

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PLC Reconstruction

The reconstruction can be fibula based such as

modified Larson’s technique or combined tibia and

fibula based such as LaPrade’s anatomical

reconstruction.

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The principles of surgeryEarly repair (within 3 weeks) of torn and detached ligaments,

tendons and capsule in acute injuries. A combination of early

repair and reconstruction has been shown to provide better

results.

Late reconstruction of the two or three of the main stabilisers of

the posterolateral corner of the knee i.e. the lateral collateral

ligament, Popliteus tendon, and popliteofibular ligament in

chronic cases.

Combined ACL/PCL and PLC injury must be treated by

reconstruction of all injured ligaments.

Isolated ACL or PCL reconstruction without addressing the PLC

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Knee dislocation

Any triple-ligament knee injury constitutes a

frank dislocation. This is relatively rare but

a severe and potentially limb-threatening

injury.

High-energy injury such as RTA.

Sporting accident.

May be missed on initial assessment.

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Vascular Injuries

Previously it was thought there was a 50%

incidence of vascular compromise Now 3.3-18%

20%–30% incidence of nerve injury.

Fracture incidence may be as high as 60%.

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Classification Classified on the basis on tibial displacement in respect to the femur

Closed or open

High or low energy

Dislocation or subluxation

Neurovascular involvement

Anterior (common: 30-50% of dislocations, associated with intimal tears)

Posterior; also medial, lateral (highest rate of peroneal nerve injury) and

rotatory (usually irreducible) or combined

Hyperextension leads to anterior dislocation

Dashboard injury leads to posterior dislocation

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Examination

Valgus and varus laxity

Anteroposterior translation

Recurvatum

>10º hyperextension suggests ACL injury

>30º hyperextension indicates PCL injury

Rotation indicates MCL and LCL injury

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ManagementSurgical emergency

Deal with life-threatening injuries first

Circulation in A&E

Serial examination for 48 hours.

Ankle brachial Index (ABI)

ABI <0.9 is suggestive of significant arterial injury

Involve the vascular surgeon

Radiography before manipulation

– (assess direction and associated fracture)

Reduction as soon as possible in the emergency/operating Room

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Management

Immobilization in an extension knee splint

Check radiograph to confirm congruity, if not,

consider external fixator

Conservative management out of favour

Early surgical reconstruction and/or repair, is

currently recommended by the Knee Dislocation

Study Group

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ManagementSurgery as soon as the vascular surgeon allows

Most ACL/PCL/MCL can be treated with bracing the MCL followed by

combined ACL/PCL reconstruction once range of movement is

restarted, usually after 6 weeks.

ACL/PCL/posterolateral corner can be treated by repairing the

posterolateral corner acutely (within three weeks) and delayed ACL/PCL

reconstruction 8 weeks later.

Open dislocation, fracture dislocation and vascular compromise require

staged procedures.45


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Health & Medicine

PCL, PLC, Knee Dislocation