The function of the posterior cruciate ligament (PCL) is to prevent the femur from sliding off the anterior edge of the tibia and to prevent the tibia shifting posteriorly to the femur. A common cause of PCL injury is a direct blow to the bent knee, such as a knee that hits the dashboard in a car accident or falls hard on the knee, both events shifting the posterior tibia to the femur.
The posterior drawer test is one of the tests used by physicians and physiotherapists to detect injuries to PCL.
Surgery to repair a controversial posterior cruciate ligament due to placement and technical difficulties.
Additional tests of posterior cruciate ligament injuries are posterior sag tests , where, unlike the drawer tests, no active force is applied. Instead, the person is stretched out with a leg held by another so that the hip is folded to 90 degrees and 90 degrees knees. The main parameter in this test is the step-off , which is the shortest distance from the femur to the hypothetical line that pertains to the tibia's surface of the tibial and upward tuberosities. Typically, the step-off is approximately 1 cm, but decreases (Level I) or even absent (Level II) or upside (Level III) in injury to the posterior cruciate ligament.
Patients suspected of having a posterior ligament injury should always be evaluated for other frequent knee injuries in combination with PCL injuries. These include cartilage/meniscus injuries, bruises in the bones, ACL tears, fractures, posterolateral injuries and collateral ligament injuries.
Video Posterior cruciate ligament injury
Cause
Related anatomy
To understand how a posterior cruciate ligament injury can occur, one should consider the anatomical and physiological properties of PCL. The PCL is located inside the knee joint where it stabilizes the articulating bone, especially the femur and tibia, during movement. It comes from the lateral edge of the medial femoral condyle and the intercondyle notch roof then stretches, at the posterior and lateral angles, toward the posterior tibia just beneath the articular surface.
Related physiological features
Although each PCL is an integrated unit, they are described as separate anterolateral and posteromedial sections based on where the site and attachment functions of each section. During knee joint movement, PCL rotates such that the anterolateral part extends in knee flexion but not in knee extension and posteromedial bundle extends in extension rather than flexion.
The type of mechanism that causes PCL injuries
In this position, the PCL function to prevent tibia movements towards the posterior and to prevent oblique or patellar shifts. However, the disadvantages of each of the two parts make PCL vulnerable to injury during hyperflection, hyperextension, and in a mechanism known as a dash injury. Since the ligaments are viscoelastic (page 50) they can handle a higher amount of stress only when the load is raised slowly (p.30). When hyperflexion and hyperextension occur suddenly in combination with this viscoelastic behavior, PCL destroys shapes or rips. In the third and most common mechanism, the dashboard injury mechanism, the knee is impacted in the posterior direction during flexed knee against space above the tibia. This mechanism occurs in the excessive rotation of the external tibia and during falling which causes a combination of extension and tibia adduction, called the varus-extension voltage, or which occurs when the knee is flexed.
Maps Posterior cruciate ligament injury
Diagnosis
Prevention
Knee injury
Knee injuries are very common among athletes as well as people who are active on a regular basis and can always be prevented. Ligament tears cause more than forty percent of knee injuries and a posterior cruciate ligament is considered to be one of the less common injuries. Although less common, there are still important steps that can be taken to prevent this type of knee injury. Maintaining proper exercise and sports techniques is essential for injury prevention, which includes not exceeding the body or exceeding the proper range of knee motion, proper heating and cooling
Quadriceps and hamstring ratio
Another important aspect of keeping the injury-free knee is having strong quadriceps and hamstring muscles as it helps stabilize the knee. The hamstring ratio to the low quadriceps is associated with a knee injury and should be about eighty percent. Some exercises to strengthen the quadriceps and hamstring muscles include leg curls, lift legs, susceptible knee flexions with resistance bands and knee extensions. Some stretches to help prevent injury to the posterior cruciate ligament include stretching the hamstring muscles by extending the legs, pointing toes upward, leaning forward until the stretch is felt and held for a few seconds.
Exercise and stretch
In addition, balancing practice has also been adopted because it has been proven that people with poor balance have more knee injuries than those who have a good balance. Bosu's wobbly boards and balls are very common equipment used to balance and help prevent knee injuries as long as they are used with trained personnel. Another possible measure of prevention is wearing a knee strap to help stabilize the knee and protect it from injury, especially during a demanding sport such as football.
Treatment
It is possible for PCL to heal by itself. Surgery is usually required in ligament tears. Surgery usually occurs after a few weeks, to allow for decreased swelling and regular movement to return to the knee. A procedure called ligament reconstruction is used to replace a torn PCL with a new ligament, which is usually a graft taken from a hamstring or Achilles tendon from the parent pouch. Arthroscope allows complete evaluation of all knee joints, including the knee (patella), cartilage surface, meniscus, ligaments (ACL & PCL), and joint lining. Then, the new ligaments attached to the femur and lower leg with a screw to hold it in place.
Rehabilitation
Injury class
The posterior cruciate ligament lies inside the knee. Ligaments are strong tissue bands that connect bones. Similar to the anterior cruciate ligament, PCL connects the femur to the tibia. There are four different classification classes in which doctors classify PCL injuries: Grade I, PCL has a tear. Grade II, a minimal PCL ligament tear and become loose. Grade III, a fully torn PCL and knee can now be categorized as unstable. Grade IV, ligaments damaged along with other ligaments placed on the knee (ie ACL). With this level of PCL injury, there are different treatments available for such injuries.
Rehabilitation options
It is possible for PCL to heal itself without surgery while in Class I and II. PCL injuries diagnosed in this category can reduce their recovery time by performing certain rehabilitation exercises. Fernandez and Pugh (2012) found that after a diagnosis of PCL grade II, a 8-week multimodal treatment consisting of chiropractic lumbopelvic manipulation, physiotherapy, and an exercise program that emphasized the eccentric muscle contraction (lunges, foot squat, and stem stabilization ) that proved to be an effective way to recover from PCL injuries. For Class III and IV, operative surgery is recommended or usually required. Grafts is a method when handling PCL injuries that require surgery. With a graft, there are different methods such as the tibial inlay or tunnel method.
Epidemiology
Percentage of PCL for other knee injuries
According to a posterior cruciate ligament injury only causes 1.5 percent of all knee injuries (figure 2). If it is a single injury in the posterior cruciate ligament requiring surgery for only 1.1 percent compared to all other cruciate operations, but when there are multiple knee injuries, the posterior cruciate ligament accounts for 1.2 percent of injury.
National stats
In 2010 national statistics were performed by the Health and Quality Research Agency for a posterior cruciate ligament injury. They found that 463 patients were discharged due to multiple types of PCL injuries. The age group of 18 to 44 years was found to have the highest reported injury (figure 1). One of the reasons why this age group consists of most of the injuries to PCL is because people are still very active in sports at this age. Men were also reported to have more injuries to PCL (Figure 3).
Recommendations for operations
A grade III PCL injury with more than 10mm of posterior translation when posterior examination of the drawer is performed can be treated surgically. Patients who do not improve stability during physical therapy or develop increased pain will be recommended for surgery.
References
External links
- lljoints at The Anatomy Lesson by Wesley Norman (Georgetown University) ( antkneejointopenflexed )
- Dealing with Ligament Tearing at Knee
- http://www.orthspec.com/pdfs/PCL-injuries.pdf
Source of the article : Wikipedia
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