Ligaments are one of the primary structures providing stability to the knee joint. There are four main ligaments and components of the knee which include: lateral collateral ligament (LCL), anterior cruciate ligament (ACL), posterior cruciate ligament (PCL), and medial collateral ligament (MCL). An injury to one or more ligaments of the knee can result in immediate pain or swelling, and in some cases, difficulty moving or bearing weight through the knee. This can influence an individual’s ability to walk or run immediately after the injury.
Knee ligament injuries can involve a sprain or complete tear of one or more ligaments. These injuries result from excessive force or twisting at the knee during a fall or high-impact force. The direction of force or twist at the knee will influence which ligament becomes injured. Sport-related injuries are a common cause of knee ligament injuries, however, any trauma to the knee can result in a ligament injury.
Four ligaments in the knee are subject to injury from falls or direct trauma. Although the knee functions well with normal activity, it is the most frequently injured joint in the body when exposed to trauma. Excessive twisting or stretching forces will overcome ligament structures, resulting in either sprain or tear. The direction of force will determine which ligament(s) are injured.
ACL injuries are more common in female athletes and in sports that involve pivoting or cutting. Other causes can include an auto accident, a fall, or twisting when stepping down off a step.
Depending on the severity, a knee ligament injury may include a loud popping sound or sudden onset of pain. Swelling is common within the first 24 hours of injury. This type of injury may result in the knee feeling unstable or unable to bear weight through the injured leg. Full knee range of motion may be limited due to pain or swelling.
Immediate pain and swelling in the knee may follow an injury, and depending on severity, the knee may not be able to move normally or bear weight.
Knee ligament injuries can be diagnosed by a thorough hands-on examination. Physical therapists have a series of examination steps and ligamentous integrity tests to identify the presence of ligament injuries. Ligament injury can be further confirmed through magnetic resonance imaging (MRI).
Grade 1 or 2 ligament sprains can be treated conservatively with physical therapy. Grade 3 sprains occur when the ligament is completely torn or ruptured. In many cases, depending on the activity level and goals of an individual, grade 3 injuries require surgical intervention for recovery.
For a complete (grade 3) tear of the ligament, knee surgery will be indicated in most cases. Recovery after surgery will vary according to the surgeon's protocol and the type and severity of the injury. For most partial tears (grades 1 or 2), surgery is not needed and a full recovery can be gained through personalized physical therapy. Treatment focuses on strengthening of the quadriceps, hamstring and gluteal muscles, while restoring normal mobility as the ligament heals. End-stage coordination exercises (also known as proprioceptive exercises) are needed to ensure an athlete or worker is ready to return to full activity. This will ensure the muscles react quickly in a coordinated manner to protect the knee from future trauma.
Physical therapists will aim to treat the pain or swelling initially if the injury is acute. The next goal of rehabilitation will be to restore range of motion and strength to the knee and surrounding joints. Results Physiotherapy uses a hands-on approach and combines that with an individualized exercise program to achieve optimal outcomes. Recovery for low-grade sprains (grade 1 or 2) can be gained through physical therapy alone and may take 2-6 weeks in duration. Grade 3 injuries, may warrant surgery in many cases and will include physical therapy for 4-8 months following surgery. This may take up to 12 months to fully recover.
Strengthening the muscles around the knee and training muscle control through exercise can assist with injury prevention. Training and agility activities including pivoting, cutting, and jumping are important for athletic injury prevention. Additionally, year-round conditioning and proper warm-up is recommended for athletes.
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