Posterior Cruciate Ligament Tears: Symptoms, Types, Causes and Treatment

Symptoms of Posterior Cruciate Ligament Tears

When the posterior cruciate ligament (PCL) is injured, the signs can be subtle compared to other ligament injuries—yet understanding the symptoms is crucial for early recognition and optimal recovery. Patients often overlook PCL injuries or attribute knee discomfort to other causes, making awareness of the symptom profile essential for both patients and clinicians.

Symptom	Description	Severity Spectrum	Sources
Pain	Aching or sharp pain at the back of the knee	Mild to severe	1 4 7
Swelling	Knee swelling, often within hours	Mild to significant	1 4 7
Stiffness	Difficulty bending or straightening	Common, can limit motion	1 4
Instability	Feeling of the knee “giving way”	More common in severe/combined tears	1 7

Table 1: Key Symptoms of PCL Tears

Pain and Swelling

Pain is the most immediate and consistent symptom following a PCL tear, usually felt deep within or at the back of the knee. Swelling commonly follows, appearing within a few hours after the injury and often leading to a feeling of tightness or fullness in the joint. This swelling may limit how much you can bend or straighten your knee comfortably 1 4 7.

Stiffness and Restricted Movement

Many people with a PCL injury notice their knee becoming stiff. This stiffness is partly due to swelling but can also result from the body’s instinct to protect the injured ligament. Movement may be especially difficult in the first hours to days after the injury 1 4.

Instability and Functional Problems

Unlike anterior cruciate ligament (ACL) injuries, PCL tears are less likely to cause immediate, dramatic instability. However, with more severe tears or those involving multiple ligaments, people may notice that their knee feels unstable, weak, or as if it might “give way,” especially when going downstairs or walking on uneven surfaces 1 7.

Subtle Presentations in Partial Tears

Partial PCL tears might not cause significant symptoms and can be easily overlooked. Some individuals may only notice a vague discomfort or sense that their knee isn’t functioning quite right, especially during athletic activity that involves stopping or changing direction quickly 4 5.

Types of Posterior Cruciate Ligament Tears

PCL tears are not all alike. Understanding the specific type and grade of injury can help guide decision-making for treatment and predict long-term outcomes. The classification of PCL injuries takes into account the severity, location, and whether other structures in the knee are also damaged.

Type	Description	Common Scenarios/Features	Sources
Grade I	Partial tear, minimal instability	Mild symptoms, usually non-surgical	3 8
Grade II	Partial tear, moderate instability	May affect function, treated conservatively or surgically	3 8
Grade III	Complete tear, severe instability	Often needs surgery, may involve other ligaments	8 7 5
Avulsion	Ligament pulls off a piece of bone	Common in children, surgical if displaced	4 7
Isolated	Only PCL is injured	Less common, typically low-impact	3 5 7
Combined	PCL and other knee ligaments injured	High-impact trauma, requires surgery	2 5 8

Table 2: Types and Classifications of PCL Tears

Grading Severity: I, II, and III

• Grade I (Mild): Only part of the PCL fibers are torn. The knee remains relatively stable with minimal functional loss. These injuries are most often managed with bracing and rehabilitation 3 8.
• Grade II (Moderate): A more significant portion of the ligament is torn, leading to noticeable looseness in the knee. Functional problems may arise, and treatment can be either conservative or surgical depending on symptoms 3 8.
• Grade III (Severe): The PCL is completely torn, resulting in pronounced instability. These are more likely to involve additional injuries to the meniscus, cartilage, or other ligaments, especially in high-energy trauma 8.

Avulsion Fractures

In some cases—especially in children—the PCL pulls off a fragment of bone from where it attaches, known as an avulsion fracture. These are often missed on standard X-rays and may require surgical repair if the bone fragment is significantly displaced 4 7.

Isolated vs. Combined Injuries

• Isolated PCL tears: These occur when only the PCL is damaged, generally the result of lower-energy trauma such as a sports injury or fall. They are less common than combined injuries 3 5 7.
• Combined PCL injuries: High-energy events like car accidents can injure the PCL along with other ligaments (ACL, MCL, LCL) and structures within the knee. These complex injuries typically require surgery 2 5 8.

Acute vs. Chronic Tears

Acute tears occur suddenly and are often linked to a specific incident, while chronic tears develop gradually, sometimes as a result of repeated minor injuries or unrecognized acute trauma 7 5.

Causes of Posterior Cruciate Ligament Tears

PCL tears have distinct causes, often differing from the more well-known ACL injuries. Understanding how and why these injuries occur can help with prevention and early recognition.

Cause	Mechanism/Scenario	At-risk Population	Sources
Direct blow	Force to front of upper tibia (“dashboard injury”)	Car accident victims	3 4 7
Sports trauma	Fall on flexed knee, hyperextension	Athletes, especially in contact sports	3 4 7
Hyperflexion	Extreme bending of the knee	Football, rugby players	3 4
Hyperextension	Knee forced backward beyond normal limits	Gymnasts, athletes	3 4
Combined trauma	Multiple ligaments injured in high-energy impact	Motor vehicle accidents, severe sports injuries	2 5 8

Table 3: Common Causes of PCL Tears

Direct Impact: The “Dashboard Injury”

Perhaps the most classic cause of a PCL tear is a direct blow to the front of the upper shin (tibia) while the knee is bent. In car accidents, this happens when the knee strikes the dashboard, driving the tibia backward and overstretching the PCL 3 4 7.

Sports-Related Injuries

Athletes are especially prone to PCL injuries due to the dynamic and sometimes unpredictable movements involved in sports:

• Falling onto a flexed knee (with the foot pointed downward) can force the tibia backward and tear the PCL 3 4.
• Hyperextension injuries, where the knee bends backward past its normal range, can rupture the ligament 3 4.
• Contact sports like football and rugby have higher rates of PCL injuries due to frequent tackles and falls 3 7.

High-Energy, Multiple-Ligament Injuries

Major trauma, such as that sustained in a severe automobile accident or a significant fall, often injures the PCL along with other knee structures. These combined injuries are complicated and typically require surgical intervention 2 5 8.

Pediatric Considerations

In children, PCL injuries more often involve an avulsion fracture—where the ligament pulls off a piece of bone rather than tearing through its substance. This is due to the relative weakness of growing bone compared to ligament strength in young people 4.

Less Common Mechanisms

• Hyperflexion: Forcing the knee into deep bending beyond its normal limits can place excessive strain on the PCL 3 4.
• Non-contact injuries: Although less common, sudden stops or changes in direction can sometimes lead to PCL tears, particularly in athletes 3.

Treatment of Posterior Cruciate Ligament Tears

Treatment of PCL tears has evolved, with most isolated injuries managed non-surgically, but surgical options reserved for severe, combined, or symptomatic chronic tears. The approach depends on the injury’s type, severity, and impact on knee function.

Treatment	Description	Typical Indication	Sources
Rest/Immobilization	Bracing, splinting to limit knee movement	Mild/acute isolated tears	1 3 7 8
Rehabilitation	Strengthening, range-of-motion exercises	All grades, critical for recovery	1 3 7
Surgical Repair	Ligament reconstruction, fixation	Severe (Grade III), combined injuries, failed conservative treatment	2 5 7 8
Pediatric Specific	Avulsion fracture fixation	Displaced avulsion fractures	4 7

Table 4: Main Treatment Options for PCL Tears

Non-Surgical Management

Most isolated PCL tears, particularly Grades I and II, respond well to non-operative treatment:

• Rest and immobilization: Initial management may involve splinting or bracing the knee in extension to prevent further injury 1 3 7.
• Rehabilitation: As soon as pain and swelling permit, physical therapy focuses on restoring range of motion and strengthening the quadriceps muscle, which helps stabilize the knee against backward movement of the tibia 1 3 7.
• Gradual return to activity: Once muscle strength and knee stability are restored, most patients can return to previous activities, although high-impact sports may require a more cautious approach 1 3 7.

Surgical Management

Surgery is reserved for specific situations:

• Acute Grade III tears: Complete PCL ruptures causing significant instability, especially in active individuals or those with physically demanding jobs, may require reconstruction 8.
• Combined ligament injuries: When the PCL tear occurs along with injuries to other ligaments (ACL, MCL, LCL), surgical repair is usually recommended to restore knee stability 2 5 8.
• Chronic symptomatic tears: Long-standing PCL injuries that continue to cause pain, instability, or functional limitations despite rehabilitation may benefit from surgery 7.

Surgical techniques:

• Single-bundle reconstruction: Focuses on restoring the larger anterolateral bundle, the most common surgical approach 3 8.
• Double-bundle reconstruction: Aims to more closely mimic natural ligament anatomy, potentially improving knee stability, but clinical differences remain under study 3 6 8.
• Tibial inlay techniques: Newer methods designed to reduce graft stretching and improve outcomes 6 7.

Pediatric Considerations

For children and adolescents, the treatment approach depends on the injury type:

• Minimally displaced avulsion fractures and mid-substance tears are generally managed non-operatively.
• Displaced avulsion fractures—where the bone fragment is significantly out of place—require surgical fixation to restore normal knee anatomy and function 4 7.

Emerging Approaches and Outcomes

Recent advances in surgical technique, imaging (such as stress radiography), and understanding of PCL anatomy have improved outcomes for both conservative and surgical management 6 8. The choice between single- and double-bundle reconstruction, as well as various fixation techniques, continues to evolve, with ongoing research needed to determine best practices 3 6 8.

Conclusion

Posterior cruciate ligament (PCL) tears can be complex and are often overlooked due to their subtle symptoms compared to other knee injuries. Early recognition, accurate classification, and tailored treatment strategies are essential for optimal recovery and prevention of long-term knee problems.

Key points:

• PCL tears often present with pain, swelling, stiffness, and, in severe cases, instability 1 4 7.
• They are classified by severity (Grade I-III), location (mid-substance vs. avulsion), and whether other structures are injured 3 4 8.
• Causes include direct blows (dashboard injuries), sports trauma, hyperflexion/hyperextension, and high-energy combined injuries 3 4 7.
• Most isolated PCL tears are managed non-surgically with rest and rehabilitation, while severe or combined injuries may require surgical reconstruction 1 3 7 8.
• Pediatric injuries often involve avulsion fractures, with treatment tailored to the degree of displacement 4.
• Ongoing research continues to refine both surgical and conservative treatment strategies, improving long-term outcomes for patients 6 8.

Understanding the nature of PCL injuries empowers patients and clinicians alike to make informed decisions and support a safe, successful return to activity.