Knee pain can be debilitating. It can make everyday activities harder and can completely sideline us from sports, exercise and active hobbies. For athletes, knee injuries can end promising careers and impact their livelihoods.
While ACL (anterior cruciate ligament) injuries are the most common knee injuries in athletes and active people, PCL (posterior cruciate ligament) injuries are most likely to occur in car accidents.
Here’s what you should know about this important ligament, symptoms of PCL injuries and treatments to repair the damage.
What is the Posterior Cruciate Ligament (PCL)?
The posterior cruciate ligament is one of four ligaments in the knee. It is one of two ligaments–the PCL and the anterior cruciate ligament (ACL)–that connect the femur (thighbone) to the tibia (shinbone). Together, the PCL and the ACL form a X-shaped band of tissue that sits behind the center of the knee. This X-shaped band of ligaments helps stabilize the knee joint during certain movements.
The PCL is the largest and strongest ligament within the knee. It is responsible for the majority of stabilization against hyperflexion and against forward and backward movement of the femur and tibia.
Due to its size (it is 1.3 to 2 times thicker than the ACL), the PCL is less vulnerable to injury than the ACL. However, PCL tears and sprains still occur in certain situations, and they can cause serious instability and structural damage within the knee joint.
What Causes a Posterior Cruciate Ligament Tear?
Because of its strength and size, injuries to the PCL require a powerful external force.
Car accidents are the cause of most strains and injuries to the posterior cruciate ligament1. In fact, PCL injuries are sometimes called “dashboard” injuries because the ligament is often damaged when a knee makes contact with a dashboard during a car crash.
Another common cause of these injuries is falling onto a bent knee or being hit while playing a contact sport. Football, soccer, skiing and rugby produce a high rate of PCL injuries. This is because these sports require athletes to collide with one another, produce a high number of athlete falls, or both2. Overall, 57% of PCL injuries are caused by high-impact trauma to the knee3.
In addition to high-energy impacts, certain movements like hyperextension (bending the knee backward) can cause a PCL injury. Hyperextension of the knee can occur during sports like gymnastics, basketball, football, lacrosse and skiing. It can also occur during simple everyday movements, tripping or missteps.
Many PCL injuries occur in combination with damage to other ligaments, cartilage and tendons in the knee. In fact, 79% of grade III PCL tears cause concurrent damage to the ACL, MCL (medial collateral ligament) and the PLC (posterolateral corner).
Different Types of PCL Injuries
Like ACL injuries, PCL injuries are categorized by grades:
Grade I Sprain: The PCL is mildly damaged or stretched. Some instability and pain may occur, but the knee joint remains stable.
Grade II Sprain: This injury is known as a partial tear and occurs when the ligament is stretched severely enough to cause the ligament to become loose. The knee joint is destabilized and may have decreased range of motion. The knee may also periodically give out during movement.
Grade III Rupture: The PCL is completely torn, and the knee joint is totally destabilized. Other ligaments and structures in the knee may also be damaged.
Symptoms of Posterior Cruciate Ligament Injuries
According to the American Academy of Orthopaedic Surgeons, the main symptoms of a PCL injury are immediate pain and swelling, stiffness and instability in the knee joint.
Some individuals with a PCL injury may not experience severe pain, but may have swelling, difficulty walking or a feeling that the affected knee is “giving out” during movement.
How Are PCL Injuries Diagnosed?
If you suspect you have a damaged ligament in your knee, it is important to visit an orthopaedic doctor immediately.
During your appointment, your doctor will ask you about your symptoms and medical history and perform a physical examination of your knee. The physical examination will include movement tests that compare your injured knee to your non-injured knee. If you have a PCL injury, your doctor may note changes in appearance such as swelling or fluid on the knee, as well as changes in movement when the knee is bent or when you walk.
To confirm your diagnosis, you may also be asked to undergo X-rays and an MRI so your doctor can see damage to the bones and soft tissues of the knee. X-rays can show avulsion fractures (a chunk of bone that was torn off) that occurred during a PCL injury, while MRIs can show the PCL itself.
MRIs are the most accurate diagnostic test for identifying a ruptured PCL. However, they may not be conclusive for mild-to-moderate sprains.
If an MRI doesn’t provide enough insight on the extent of PCL damage, your doctor may recommend arthroscopy. This procedure provides your doctor with an inside look at the structures of your knee via a small camera that is inserted through a tiny incision.
Treatment of PCL Injuries
Treatment for PCL sprains and tears depends on the extent and age of the injury.
Grade I and Grade II sprains rarely require surgery. Over-the-counter pain medications like ibuprofen and naproxen can help control pain. Rest, ice, compression and elevation (the RICE method) is the first-line treatment for milder knee injuries. Physical therapy may also be recommended to restore stability, strength and function to the knee joint.
Grade III PCL ruptures typically require surgical treatment, especially if they occurred alongside other ligament, cartilage or bone injuries. Your orthopaedic doctor may also recommend surgery if you have suffered repeated PCL injuries or if you continue to have pain and knee instability after the healing and rehabilitation period.
PCL surgery reconstructs the posterior cruciate ligament using a tissue graft, usually from the patient’s own body. These surgeries can be performed in an outpatient surgery center under general anesthesia. Recovery from PCL reconstruction takes 8 to 12 months, on average.
Diagnosis and Treatment of PCL Injuries at Mobility Bone & Joint Institute
Mobility Bone & Joint Institute is the only practice in the Merrimack Valley that can diagnose diseases, infuse medications, and perform x-rays on site.
Do you have questions about the diagnosis and treatment of PCL injuries at Mobility Bone & Joint Institute?
Call (978) 794-1946 or click here to schedule an appointment at our Andover, MA office.
Call (603) 898-2220 or click here to schedule an appointment at our Salem, NH office.