OVERVIEW
• The knee joint is commonly injured due to variety of causes
• The knee joint is held in place by ligaments, anatomical structures that join two bones. There are four major ligaments and several secondary ones.
• The anterior cruciate ligament (ACL) and posterior cruciate ligaments (PCL) stabilize the knee joint during forward and backward movements and cross each other in the middle of the knee joint
• The medial collateral and lateral collateral ligament (LCL) stabilize the knee joint during side to side movements of the knee.
• The meniscus is made of tough rubbery cartilage and acts as a shock absorber between the femur and tibia
• Common knee injuries include sprains, overuse, bursitis, fractures, dislocations and ligament tears.
• Knee injuries usually occur due to twisting or bending of the knee during sports activities, trying to get out of a car or a direct blow to the knee from accidents, falls or sports injuries.
• The sensation of instability or a feeling of giving away at the knee is often due to an injury to one of the ligaments at least resulting in the bones not being held in position strongly enough.
• Non-ligament related causes of knee pain and instability include fractures, bursitis, patellar tendinitis and various types of arthritis
• Risk factors for knee injury include overuse, weak bones from osteoporosis, improper training, and playing high-impact sports such as football and soccer
• The predominant symptoms of knee injury include pain and swelling and limitation of movement

TYPES OF LIGAMENT INJURIES
• Ligament injuries usually occur due to a sudden injury where the knee buckles or forced into an abnormal position.
• Often, when a ligament is injured, it may be accompanied by partial or complete tear.
• Ligament injuries vary from microscopic tears to complete tears of the ligament that may not get better without surgery. Minor tears generally heal with some simple measures, where as more severe injuries often need further invasive treatments.

GRADING LIGAMENT INJURIES
Ligament sprains are graded according to the degree of stretching and tearing of the ligament fibers as well as the degree of instability in the knee joint
• Grade 1: The ligament is stretched and painful, but there is no tear and no instability of the knee joint
• Grade 2: There is mild degree of tear of the ligament fibers and some amount of instability.
• Grade 3: There is complete tear of the ligament fibers and the knee joint is unstable.

COMMON LIGAMENT INJURIES:
• Anterior Cruciate Ligament (ACL) Tear:
The ACL is central within the knee and connects the tibia and the femur. Most ACL tears require surgery.
• Medial Collateral Ligament (MCL) Tear:
The MCL is on the inner side of the knee joint and MCL tears most often occur when the knee is struck from the outside, pushing the inner side of the knee open. Most MCL tears heal with nonsurgical treatment.
• Posterior Cruciate Ligament (PCL) Tear:
The PCL crosses the ACL and prevents forward movement of the tibia. The PCL is typically injured by falling and landing on the knee joint. PCL tears can be treated non-surgically if their injury is isolated, but may need surgery when accompanied by other injuries
• Meniscal tears:
The menisci can be torn by sudden twisting of the knee while bearing weight on it or due to overuse or aging process.

CLINICAL FEATURES OF KNEE JOINT INJURY
The location and severity of knee pain varies according to the cause. Common signs and symptoms of knee joint injury include
• Pain and swelling
• Redness and warm to touch
• Stiffness
• Feeling of giving away or instability
• Popping or crunching noises
• Inability to straighten the knee fully

DIAGNOSIS OF LIGAMENT INJURY
PHYSICAL EXAMINATION:
• The doctor will perform a physical examination to look for pain and tenderness, warmth, any visible bruises, degree of mobility of the joint and perform tests to test the function of the various ligaments. For instance, the Lachman’s test is used to evaluate the anterior cruciate ligament.

IMAGING TESTS
• X-ray and CT scans can help to diagnose bone fractures or degenerative joint disease.
• Ultrasound uses sound waves to produce real-time images of the soft tissue structures inside and around the knee joint. The knee may be imaged in different positions during the ultrasound to detect specific problems.
• Magnetic resonance imaging (MRI) employs radio waves and a powerful magnet to produce images of the knee joint. This test is especially valuable in demonstrating injuries to soft tissues such as ligaments, tendons, muscles and cartilage.

TREATMENT OF LIGAMENT INJURIES
CONTROL SWELLING (RICE)
Rest to knee joint
Ice- Using crushed ice for 20 minutes, at least four times a day
Compression- An elastic bandage provides support and helps to reduce swelling.
Elevate- Elevation of knee

PHYSIOTHERAPY
Strengthening the muscles around knee by various exercises to reduce instability, exercises to correct movement patterns and learning the right technique during sports and activity. Exercises to improve balance and flexibility are also key to address.
Knee braces to support the area

CONTROL OF PAIN
Injection of corticosteroids, hyaluronic acid or platelet rich plasma into the knee joint may help in pain relief

SURGERY
Arthroscopic surgery is performed using a fiber-optic camera and long, narrow tools inserted through just a few small incisions around the knee. Arthroscopic surgery is done for removal of loose bodies from the knee joint, removal or repair of damaged cartilage and reconstructing torn ligaments

PROGNOSIS OF KNEE INJURY
• The prognosis varies according to the type and severity of the injury. If the injury is significant enough to require surgery, the recovery time will be prolonged.
• Simple strains or sprains may recover in one to two weeks. More severe injuries requiring arthroscopic surgery may take up to three months to recover.
• Major traumatic injuries to the knee may require even a year to recover fully

PREVENTING SPORTS INJURIES
• Warm up before each practice or competition. Do stretching exercises especially hamstrings, quadriceps, hip and calf muscles.
• Have a trainer during exercises
• Wear proper shoes for the sport
• Change running shoes after 300-500 miles.
• Never increase activity level more than 5-10% per week and only one parameter (i.e. intensity/distance/speed, distance/slope/duration) at a time