The PCL and anterior cruciate ligament (ACL) limit the motion of the tibia backward and forward, respectively. The lateral collateral ligament (on the outside of the knee) and the medial collateral ligament (on the inside of the knee) limit side-to-side knee motion.
Each year in the United States, about 25,000 PCL injuries are diagnosed, roughly one-tenth the number of diagnosed ACL injuries. Fifty percent of PCL injuries occur in conjunction with other knee ligament injuries, while the other 50 percent occur alone and are referred to as isolated PCL injuries.
PCL tears usually result from high force impacts, generally vehicular accidents or contact sports such as football, soccer, or hockey. PCL injuries also can occur in non-contact sports, such as gymnastics or skiing, but are much less common.
A PCL injury usually occurs during a direct hit below the knee while the leg is bent. In other cases, you may land directly on a bent knee, driving the tibia up and behind the knee and tearing the PCL. Extreme hyperextension of the leg (straightening beyond the normal limit) is a third type of trauma that may result in tears to the PCL and other knee ligaments.
If untreated, a torn PCL can change knee mechanics, resulting in abnormal motion and subsequent pain and instability. Over years, this wear and tear can lead to progressive degenerative arthritis.
Symptoms of PCL injuries include:
Unlike the "pop" and severe pain that may occur with a torn ACL, an isolated PCL injury may manifest itself simply as swelling in the knee that subsides over a few days or weeks. In many cases, patients may overlook the initial injury and fail to visit a doctor or specialist for evaluation. Unlike ACL injuries, isolated PCL injuries may not initially limit knee function, allowing you to return to normal activities.
Diagnosis of a PCL injury begins with an extensive history to learn how the injury occurred. The doctor must determine what position the leg was in at the time of injury and whether the injury involved contact or a noncontact mechanism (for example, twisting). In an acute, isolated PCL injury, there is usually a history of mild pain and swelling. If the PCL and other knee ligaments are torn, the knee is severely swollen and the person is completely disabled.
Once a thorough history is obtained, the doctor performs a physical exam of the knee to assess the stability of the ligaments. Using specific tests, the physician can diagnose PCL injuries by applying forces to the knee and feeling for abnormal motion.
The examiner also must assess other knee ligaments to rule out combined ligament injuries. In severe, multiple ligament injuries, nerves and blood vessels also may be damaged. These injuries must be evaluated immediately by a doctor.
It is difficult at times to completely assess all the damage that may have occurred in conjunction with a PCL injury. In this case, obtaining additional studies such as magnetic resonance imaging (MRI) exams can be very helpful. Magnetic resonance can show the ligaments, cartilage, and bone to give an accurate picture of the extent of the injury.
Treatment for a PCL injury depends on the extent of the patient's injury, the patient's age, and the patient's desired level of activity. A young, active person with a complete PCL tear may require surgery, whereas a sedentary, middle-aged individual with a partial tear may go directly into rehabilitation.
Extensive counselling of the patient by the doctor and therapist must occur before a final decision can be made on treatment. The options for treatment include a nonoperative strengthening program and surgical reconstruction of the damaged ligaments.
Athletes can take three steps to reduce their risk of PCL injuries:
The key to improving sports performance after a PCL injury is proper a rehabilitation program, and adhering to some of those same principles after the injury is gone.
Keep in mind that the single most important aspect of improving performance is stretching before and after you step onto the field, court, ice, or golf course.
Benefits derived from stretching include:
As an athlete, your number one concern is getting back to full strength as soon as possible so that you can return to training and competition. That is why appropriate rehabilitation is extremely important.
The goals of rehabilitation are to restore range of motion and to strengthen the quadriceps muscles, which help stabilize the knee. After surgery, you may have to use crutches and a knee brace. Exercises such as squats and leg presses are used because they put less stress on the knee.
Precautions you can take at home for minor PCL injuries include:
Once swelling subsides, you will need to follow a program of physical therapy to strengthen your quadriceps muscle and regain range of motion.
Some patients require surgery to stabilize the knee. Arthroscopic surgery, which uses small incisions and pencil-sized instruments, is used to determine and repair damage to the cartilage in the knee. Avulsion fractures (tearing away) may need to be fixed with internal screws to ensure proper healing. If the PCL is completely torn, it may be reconstructed using a portion of the patellar tendon or some other autograph.
The major objectives of rehabilitation from a PCL injury are to increase hip and knee flexibility, pain-free range of motion, and strengthen the thigh muscles. In severe cases, you should avoid activity that causes knee pain altogether. In these cases, you can still maintain cardiovascular fitness by swimming or cycling if allowed by your doctor.
In some of the following exercises, both legs are to be used, which is intended to prevent the uninjured leg from developing knee pain. (The uninjured leg is forced to assume some of the workload of the injured one and so is prone to injury.) These exercises may be done more than once daily. Three times daily is best, but work up to this amount gradually.
Once posterior knee pain has been minimized, you may be able to swim, cycle, walk, stair climb, weight train, or jog, as pain allows. These activities will help you to gradually resume your normal training regimen. Remember that stretching, strengthening, and range-of-motion exercises must be continued to reduce the risk of injury recurrence.
During the period when normal training should be avoided, alternative exercises may be used. These activities should not require any actions that create or intensify pain at the site of injury. They include:
The goal of rehabilitation is to return you to your sport or activity as soon as is safely possible. If you return too soon you may worsen your injury, which could lead to permanent damage. Everyone recovers from injury at a different rate. Return to your activity is determined by how soon your PCL injury recovers, not by how many days or weeks it has been since your injury occurred. It also depends on how serious the injury is. Instances where reconstructive surgery is required will obviously create a longer recovery period than patients with a strain or knee pain.
A good rule is to allow pain to dictate when you're ready to return to activity. You should return in moderation, and back off if you feel any pain.
A typical surgery patient may be able to ride a bike at three months, start running at five to seven months, and return to competitive sports after eight to 12 months. Full recovery may take up to two years.
The ultimate goal of PCL reconstructive surgery is to provide dynamic stability while maintaining full range of motion, so that athletes can return to competitive or recreational sports. Progress is assessed by the patient's perception of how stable the knee feels and by comparing the strength and stability of the injured and uninjured knees.
You may safely return to your sport or activity when, starting from the top of the list and progressing to the end, each of the following is true:
With proper rehabilitation, the first occurrence of pain that is diagnosed and treated in its early stages with rest, ice, elevation, and compression usually lasts two weeks. If the injury has recurred several times, full recovery may take as long as six weeks.
Should poor biomechanics be the underlying problem, returning to your sport may take longer. Some athletes with anterior knee pain caused by poor biomechanics of the foot, knee, or hip, find immediate relief from pain once fitted with appropriate and effective orthotic devices or patella tracking braces.
Frequent episodes of PCL injuries may result in a ligament tear. Such a complication may require surgical treatment, and full recovery under such circumstances can take up to two years, depending on the severity.