In my practice, I often see patients in Dhaka who know about the ACL but are much less familiar with the posterior cruciate ligament, or PCL. That is understandable. PCL injuries are less common than ACL injuries, and they can be more subtle in the early stage. But they still matter a great deal. A PCL injury can affect knee stability, walking confidence, sports performance, and long-term joint health if it is missed or poorly managed. [1][2]
One important point I want Bangladeshi patients to understand is this: a PCL injury is not always as dramatic as an ACL tear, but that does not make it unimportant. Some isolated PCL injuries can heal well with appropriate bracing and rehabilitation. Others, especially when combined with damage to other ligaments, cartilage, or bone, may require surgery. [1][2]
For patients across Bangladesh, this injury commonly follows road traffic trauma, motorcycle crashes, falls onto a bent knee, or sports-related impact. The treatment plan depends on how severe the tear is, whether the knee remains stable, and whether other structures are injured at the same time. [1][2]
What the posterior cruciate ligament does
The PCL is one of the four major stabilizing ligaments of the knee. It sits behind the ACL inside the knee joint and mainly prevents the shin bone, or tibia, from moving too far backward relative to the thigh bone, or femur. [1][2]
Why it matters
I usually explain to my patients that the PCL helps the knee stay controlled when force tries to push the tibia backward. It also contributes, to a lesser degree, to resisting varus, valgus, and rotational forces. [2]
The PCL is thicker and stronger than the ACL, which is one reason it is injured less often. [1][2] But when enough force is applied, the injury can be significant.
Common causes of PCL injury
PCL injuries usually require a strong force.
Typical injury mechanisms
- a bent knee hitting a dashboard in a car crash [1][2]
- a fall onto a flexed knee during sports [1][2]
- a direct blow to the front of the knee [1]
- twisting or hyperextension injury [1]
AAOS notes that a direct blow to the front of a bent knee and hyperextension-type forces are classic causes. [1] StatPearls also notes that dashboard injuries and falls forward onto a flexed knee are among the most common mechanisms. [2]
In Bangladesh, I see these injuries not only in athletes but also in everyday road traffic trauma, especially among motorcycle riders and passengers.
Symptoms of a PCL injury
Patients do not always notice the same kind of sudden instability that they might describe after an ACL tear. That can delay evaluation.
Common symptoms
- pain in the knee after injury [1]
- swelling that appears steadily and fairly quickly [1]
- knee stiffness [1]
- limp or difficulty walking [1]
- a feeling that the knee may give way [1]
Some patients can still walk, which creates a false sense that the injury is minor. But persistent pain, swelling, or instability after the mechanism I described above should never be ignored.
Why PCL injuries can be missed
One important point I want Bangladeshi patients to understand is that a PCL injury may be less obvious than other knee injuries.
AAOS specifically notes that PCL injuries are often subtle and more difficult to evaluate than some other ligament injuries. [1] A person may think it is just a bruise from impact, especially after a fall or a dashboard injury, but deeper ligament damage may still be present.
This is one reason I pay close attention to the mechanism of injury.
Isolated PCL injury versus combined injury
This is a very important distinction.
Isolated PCL injury
If only the PCL is injured and the rest of the knee is stable, the outcome can often be good with non-surgical treatment. AAOS notes that many isolated PCL tears are partial tears with the potential to heal on their own, and some patients can return to sports without major instability problems. [1]
Combined ligament injury
Sometimes the PCL is torn together with:
- ACL
- posterolateral corner structures
- collateral ligaments
- cartilage
- meniscus
- bone
AAOS emphasizes that PCL injuries often occur along with injuries to other structures in the knee. [1] When that happens, the treatment decision becomes more complex and surgery is more likely.
How I evaluate a suspected PCL injury
When I evaluate patients with this problem, I start with the story of the injury, because the mechanism often gives the first major clue.
History
I ask about:
- whether the knee hit a dashboard
- whether the person fell directly onto a bent knee
- whether swelling came early
- whether the knee feels unstable
- whether walking, stairs, or sports feel unsafe
- whether there was another major trauma around the same time
Physical examination
On examination, I assess:
- swelling or effusion
- range of motion
- overall ligament stability
- tenderness around the joint lines
- signs of associated injury
AAOS notes that the injured knee may appear to sag backward when bent and may slide backward too far, especially beyond 90 degrees of flexion. [1]
StatPearls highlights that the posterior drawer test is the most accurate physical test for assessing PCL integrity. [2]
Imaging tests
X-rays
X-rays do not show the PCL directly, but they can show fractures or an avulsion injury where a piece of bone is pulled off. [1]
MRI
MRI is usually the most useful imaging study to evaluate the PCL and associated cartilage, meniscus, and ligament damage. [1]
