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Nonoperative Treatment of PCL Injuries: Goals of Rehabilitation and the Natural History of Conservative Care

Wang, D., Graziano, J., Williams, R.J. and Jones, K.J., 2018. Nonoperative treatment of PCL injuries: goals of rehabilitation and the natural history of conservative care. Current reviews in musculoskeletal medicine, 11, pp.290-297.

In today’s letter

• Overview of how to treat posterior cruciate ligamant injuries conservatively

• A fun infographic for you to save and use in the future

• Main Takeaway = Quad work is the most important aspect of rehab.

• 3 resources to check out to further your knowledge about PCL rehab

• Meme of the week: Anyone else working in inpatient? 😄 

PCL Injury and Conservative Treatment

Compared to the more notorious ACL rupture, posterior cruciate ligament (PCL) injuries are not as common and majority of the time, do not require surgery (if it’s an isolated PCL injury). But it still contributes to knee stability heavily.

The knee can often compensate for a PCL tear, especially with the right rehab.

The body has a natural ability to heal itself, and for the majority of patients with isolated PCL injuries, this process works just fine.

Focusing on:

1. Strength training

2. Proprioception work

3. Functionally relevant exercises

Can help the knee get back to its “original” state.

Only in more severe cases, where instability or other complications are seen, might surgical intervention be necessary. So, for most people, starting with conservative treatment is a smart move, and the prognosis is often quite good.

Mechanism of Injury

PCL injuries usually happen from trauma—either from something like a car accident (where the tibia is pushed backward by the dashboard) or a sports-related impact.

Even though these injuries are less common than ACL tears, they often involve multiple knee structures, like the meniscus or other ligaments.

Changes in Knee Biomechanics

The biomechanics of the knee change significantly when the PCL is injured. Even if the patient doesn't feel the knee is severely affected, the altered mechanics can lead to long-term issues.

For example, after a PCL injury, the tibia often slides backward more than usual, and the knee’s rotation decreases when weight-bearing. This can cause uneven distribution of pressure across the knee joint, leading to more stress on certain areas, especially the medial side.

Over time, this can lead to cartilage wear, which may increase the risk of arthritis in the affected areas, especially the medial and patellofemoral compartments.

Even though the changes might seem minor at first, if not addressed, they could lead to chronic knee pain and long-term dysfunction. So, addressing these biomechanical changes early with strengthening, and range of motion exercises is key for preventing future problems

Rehabilitation

Nonoperative care often involves:

1. Bracing: To support the knee during early recovery.

2. Rehabilitation Programs: Tailored to symptoms and functional signs. The goal is to restore full range of motion, build strength (especially the quads), and gradually return to activities.

PCL Braces

During the 1st phase, a knee brace is often used for additional protection, especially in the first 2–4 weeks. The goal of bracing is to prevent excessive posterior tibial translation (backward movement of the tibia) while still allowing movement within a safe range.

The PCL Jack brace, which applies a dynamic anterior force, has been shown to significantly reduce posterior tibial sag over time. This can be worn for up to 4 months if necessary, typically allowing full weight-bearing through a safe range of motion (0°–110°).

Rehab

Rehabilitation focuses on restoring function and stability to the knee. Early rehab is about reducing swelling, reactivating the quadriceps, and improving range of motion.

For example, after an injury, the knee may swell, and the quads might become inhibited, making it hard to bend the knee or control movements. Rehab exercises start with gentle quadriceps activation and ROM control, gradually progressing to more complex exercises as the knee heals.

One interesting thing about PCL rehab is that while the ligament itself may not fully regain its original strength after conservative treatment, many people feel perfectly fine. Their body compensates for the injury, and they can return to their normal activities without the need for surgery.

A comprehensive rehab program focuses on muscle strengthening, improving knee mechanics, and helping the patient return to their daily activities or sports without instability or pain

Long-Term Outcomes

The long-term outcomes of untreated or poorly managed PCL injuries can be significant. If left unaddressed, there’s a greater chance that patients will develop arthritis, especially in the areas most impacted by the altered knee mechanics.

This is a real concern because over time, the irregular joint mechanics (like excessive pressure on the medial side) can lead to cartilage breakdown. It’s also important to remember that PCL injuries don’t just affect the ligament itself—they can increase the risk of irritation to other structures in the knee, like the meniscus.

The combination of these factors could eventually lead to the need for a knee replacement in more severe cases. That said, with good rehab, many people recover functionally without needing surgery, and the risk of arthritis may not be as high as some studies suggest, especially if the rehab is thorough and the knee is well-supported during recovery

Clinical Tip

Hamstring Strengthening

• Hamstring exercises should be avoided or performed with caution during the early phase (Weeks 1-6) of PCL rehabilitation.

• Avoid exercises that excessively activate the hamstrings, such as hamstring curls with heavy resistance or activities that involve deep knee flexion, as these could stress the posterior tibial translation (the backward movement of the tibia), which the PCL is meant to prevent.

• In the early stages, hamstring activation should be gentle and the knee positioning should not exceed 30 degrees of flexion. Focus on isometric hamstring exercises to avoid placing undue strain on the healing ligament

“Within 0°–30° of flexion, the hamstring cannot produce a posterior shear force and the anterior angle of the patellar tendon is always larger than that of the hamstring tendons . Therefore, active flexion exercise is permissible within this range of flexion. Active flexion exercise above 30° is unfavourable because a posterior shear force can occur above this angle. Therefore, inhibition of active hamstring exercise should only be done above 30° of flexion. However, hamstring strengthening could be possible by co-strengthening (co-contraction exercise) of the quadriceps and hamstring” Kim Et al (2013)

Top 3 Resources to Check Out

And learn more about the PCL

1. PCL non-operative Rehab protocol (PDF) - LINK

2. Assessing the PCL (VIDEO) - LINK

3. Athletes Vlog after sustaining a PCL injury

Meme of The Week

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