Courtesy Dr Frank Noyes, Dr Ashok Shyam, Ortho TV

PCL and Posterolateral Corner Injuries

Overview

Posterior cruciate ligament (PCL) injuries are less common than ACL injuries but are often more technically demanding to diagnose and treat. These injuries frequently occur following high-energy trauma and are commonly associated with multiligament knee injuries.

Associated injuries may include:

PCL + MCL injury
PCL + posterolateral corner (PLC) injury
PCL + ACL injury
Knee dislocations

Mechanism of Injury

Common Mechanisms

The classic mechanism involves:

Direct anterior blow to the tibia causing posterior tibial displacement

Common causes include:

Sports-related contact injuries
Road traffic accidents
Motorcycle accidents

Initial Assessment

Rule Out Neurovascular Injury

The first and most important step is evaluation for vascular injury, particularly involving the popliteal artery.

Posterior tibial displacement can stretch vascular structures and cause:

Immediate vascular compromise
Delayed vascular injury

Important Principles

Frequent neurovascular monitoring is essential
Early vascular surgery involvement may be required
Knee dislocations should always be considered limb-threatening injuries

PCL Anatomy

Structural Components

The PCL is the largest ligament in the knee and consists of:

Anteromedial bundle
Posterolateral bundle

Associated structures include:

Ligament of Wrisberg
Ligament of Humphrey

Function

The PCL primarily functions to:

Prevent posterior tibial translation
Stabilize the knee during flexion

Non-Operative Management of Isolated PCL Tears

Why Conservative Treatment Works

Compared to the ACL, the PCL has:

Better vascularity
Greater healing potential

Many isolated PCL injuries can heal satisfactorily without surgery.

Treatment Principles

The key objective is maintaining the tibia in an anteriorly reduced position while healing occurs.

Methods

Posterior support brace
Cast with posterior padding
Prevention of posterior sag

Typical Protocol

Immobilization for approximately 4 weeks
Controlled rehabilitation afterward

Outcomes

Possible healing outcomes include:

Complete healing
Partial healing with mild posterior laxity
Functional stability despite residual laxity

Posterior laxity less than approximately 6 mm may still allow good function without surgery.

Indications for Surgery

Surgical reconstruction is generally indicated for:

Posterior translation greater than 10–12 mm
Persistent instability
Difficulty with deceleration activities
Instability while walking downhill
Combined ligament injuries

Graft Considerations in PCL Reconstruction

Single-Bundle vs Double-Bundle Reconstruction

Double-Bundle Reconstruction

Advantages:

More anatomical

Disadvantages:

Technically demanding

Current Trend

Many surgeons now prefer:

Large single-bundle graft reconstruction

This can adequately cover approximately 60–70% of the native footprint and provides satisfactory clinical outcomes.

Graft Options

Common graft choices include:

Quadriceps Tendon Autograft

Often preferred in athletes because of:

Large graft diameter
Strong fixation potential

Achilles Tendon Allograft

Useful especially in:

Multiligament reconstructions

Allografts

Advantages:

Reduced donor-site morbidity
Useful when multiple grafts are required

Bone–Patellar Tendon–Bone Graft

Usually considered too small for isolated PCL reconstruction.

Surgical Technique of PCL Reconstruction

Modern Techniques

Current approaches commonly use:

All-inside arthroscopic reconstruction

Older open posterior approaches are now less frequently used.

Technical Challenges

Neurovascular Risk

One of the greatest technical concerns is the proximity of the popliteal neurovascular structures.

Important point:

Neurovascular structures may lie only 4–5 mm from the tibial tunnel

This creates significant risk during tunnel preparation.

Instrumentation

Specialized instrumentation improves safety and accuracy.

Common tools include:

Curved instruments for posterior access
Safety drill guides
Posterior arthroscopic portals
Flip-cutter systems

Tibial Tunnel Placement

Landmark

The tibial tunnel is placed near the:

“Teardrop” area of the posterior tibia

Key Precautions

Avoid drilling below the teardrop
Avoid posterior capsule violation
Use controlled drilling techniques

Femoral Tunnel Placement

Goal

Restore anatomic femoral footprint coverage

Common Techniques

Outside-in drilling
Flip-cutter technique

The flip-cutter technique has become increasingly popular because it simplifies tunnel creation.

Graft Fixation

Femoral Side

Commonly uses:

Suspensory fixation
Button systems

Tibial Side

Usually fixed with:

Interference screw fixation

Rehabilitation After PCL Reconstruction

Key Principles

Rehabilitation is critical for successful outcomes.

Important Goals

Prevent posterior sag
Protect graft healing
Restore controlled motion

Early Rehabilitation Precautions

Avoid Early Hamstring Activation

Hamstring contraction increases posterior tibial translation and may stress the graft.

Bracing

Braces should maintain:

Anterior tibial support

Motion

Early controlled range of motion is encouraged
Excessive stress should be avoided

Posterolateral Corner (PLC) Injuries

Importance

PLC injuries commonly accompany PCL injuries and must be recognized and treated appropriately.

Failure to address PLC instability can lead to:

Persistent instability
PCL graft failure

Structures Involved in PLC Injuries

Key structures include:

Fibular collateral ligament (LCL)
Popliteus tendon
Posterior capsule

Management of PLC Injuries

Acute Injuries

Typically treated with:

Repair plus reconstruction

Common strategy:

Single graft spanning fibula to femur

Chronic PLC Injuries

Usually require formal reconstruction using:

Achilles tendon allograft
Bone–tendon–bone grafts

Posterolateral Advancement

Indication

Stretch injuries without complete rupture

Technique

Existing posterolateral structures are advanced and tightened.

Most commonly used in:

Chronic laxity situations

Surgical Principles in PLC Reconstruction

Protect the Common Peroneal Nerve

Identification and protection of the nerve are mandatory during surgery.

Goals of Reconstruction

Restore lateral stability
Prevent hyperextension instability

Rehabilitation After PLC Reconstruction

Rehabilitation following PLC surgery is generally more cautious than ACL rehabilitation.

Common Strategies

Rigid immobilization initially
Bivalve cast or brace
Supervised controlled motion progression

Key Takeaways

Always rule out vascular injury first
Many isolated PCL tears heal successfully without surgery
Surgery is indicated for significant instability or combined injuries
PCL reconstruction is technically demanding
Proper tunnel placement is critical
PLC injuries must be treated to prevent graft failure
Rehabilitation plays a major role in final outcome

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