ACL Injury : Anterior Cruciate Ligament sprain



ACL Defined

A Runner’s ACL injury may occur when there is an overstretching to the knees ligament.  The knee joint is said to be the largest joints in the human body. This is a sophisticated and yet vital organ for athletes. It is made up of complex hinge structure and cushioning material (cartilages) it has ligaments that control movement. The thigh bone and the shin are held by the ligaments that help you to walk, run and bend with ease.

Mostly this happens when an athlete rapidly stops or changes direction. Medical experts claim that such motion impacts the knee by making it buckle or lock. The overstretching in the ligament can cause a tear that may be partial or full. More sporting or athletic activity following the injury may cause more damage to the ligament. The ACL is one of the four major ligaments that is known to provide stability to the knee joint. The ligaments are fibrous bands that attach bone to bone. As an athlete, it is important to note that this structure is what controls the motion of the knee joint. It also protects your lower leg from sliding too far forward.


ACL Epidemiology

Research shows that in the United States there are between 100,000 to 200,000 ACL injuries per year. The incidence in the general population is reported to be standing at approximate of 1-3500 in a year. However, this observation is not conclusive as there is no available standard surveillance mechanism for the general population. The records available are for the athletes who are just a small percentage of the population. Mostly, ACL tears are non-contact athletic injuries, and football players are reported to have high incidences of the knee injuries. Recreational alpine skiers are also at a high rate of getting the injury. Women’s ice hockey and men’s baseball have the lowest incidences of getting these injuries.

The Runner’ ACL Injury Symptoms And Signs

• Popping sound or sensation in the knee. There may occur a loud pop sound inside the knee when thee tear happens.
• Severe pain and inability to undertake sporting activities like jumping, running or bending.
• Swelling in the knee that occurs a few hours after the impactful event
• An athlete can have a visible deformity after the injury occurs.
• Loss of range of motion
• The athlete may experience the feeling of instability or “giving way” or “giving out” with weight bearing
• A black or blue discoloration appears around the knee due to bleeding in the knee joint.
• The injured ligament may lack tension capability.

Types of sprains

The ACL injury can be classified through the grading system as shown below:
Grade I- This class is composed of mild injuries that occur due to tiny tears in the ACL. They may stretch the ligament out of shape but won’t hinder the knee from supporting the weight.
Grade II – Here the ligament is partially torn. The knee becomes unstable, walking and standing at this level may be marred by difficulty.

Grade III – This is a severe injury and the ACL is completely torn. The knee is very unstable at this level. Walking, standing and other activities may be almost unachievable.


ACL injuries are often associated with sports that involve sudden stops, jumping, or changes in direction. The popular games where individuals can suffer ACL injury are soccer, basketball, football downhill skiing, volleyball, and gymnastics.   An ACL injury usually causes instability in the knee, and the patient may suffer pain and difficulty while walking, running, pivoting jumping or landing. An injury to the knee, doctors say, can be one, of the most devastating and difficult injuries to recover from.   In a nutshell here are the causes of ACL injury:
Rapidly slowing down
• A sudden change of direction
• Pivoting while your foot is firmly planted
• Forceful landing from a jump
• Incorrectly landing from a jump
• Sudden stopping
• A direct blow or collision to or on the knee like in football tackles.

ACL Risk factors

Sportspersons engaging in soccer, basketball, volleyball, downhill skiing and running are at much high risk of suffering these injuries. Females are four times likely to suffer the injury than males in the same sport and same level. It is indicated that in college the risk of ACL injury on any particular athlete is as high as 16 percent over a four –year period.


Runners’ ACL injuries are common among young sportsmen. It is estimated that America is having more than 250,000 people suffering from it each year. It is more prevalent to people in athletes and those aged between 15 and 45. As more and more people are engaging in sporting activity, these injuries have been seen to increase.

Non-contact ACL injury

It has been confirmed that most of the ACL tears are non-contact. This tear can occur when a sportsperson twists his or her knee in a forceful way or when you plant your leg and suddenly change direction. Most of the tear occurs in sporting traumas which comes with cutting and planting. An overstretching causing the tear can occur during a change of motion or during running.

ACL Injury among Female athletes

Females are observed to have a higher risk of suffering an ACL injury than men. The reason behind this observation can be the understanding that females tend to change direction differently from men. The changing of direction is known to be the major cause of the injuries. This trend can be changed through supervised training, which improves leg strength and jumps landing techniques.

Sports specialists have demonstrated that supervised training for female athletes in high school and college may serve to reduce ACL injury rate in volleyball and basketball players. Subsequently, soccer and football players have shown indications they are benefiting from such supervised training.   The training may involve programs to improve lower body and trunk strength. This will serve to re-train jumping and cutting which eventually decreases the risk of a tear in females. Those who fail to have training programs will continue suffering from tears and injury while attending such a program might reduce the risk by a large percentage.

Recommended Knee strengthening exercises

The alternative for surgery would be to use isometric exercises that can strengthen the weak muscles around the knee. Some of this strengthening exercise includes the following:
Quadriceps strengthener- you can do it by laying on the back, placing a rolled towel or a small soft roller beneath the knee lift the thigh muscles so as to straighten the knee muscle. Hold the contraction for 5 seconds then release. Repeat this exercise 10 times on each side.
Straight leg raise- this involves lying on the back and raising one leg to up to 6 inches while the other is laying flat on the floor. Hold the raised leg up for 10 seconds then release. Repeat the exercise for some time then try it on the other side.
Hip abduction- here you will lay on the back on the floor. Then bend knees keeping the feet on the floor. Place a small pillow between the knees. Then squeeze the legs towards the pillow and hold for up to 10 seconds release and repeat for 20 times.
Hip raise- laying on the floor and bending the knees, keeping the feet on the floor. Make your heels move closer to the butt. Pushing off with the heels, lift the hips up towards the ceiling and hold for 10 seconds. Release and repeat for 20 times.

ACL Injury Prevention And Prevention Programs

Exercise and expert or supervised training are the most efficient way of preventing risks of incurring this injury. Young athletes are always advised by their trainers to protect their knees. Here are tips that would help you in protecting the knees form an injury:
• Developing body awareness and strength to help in supporting the knees
Learning how to jump, land, stop and move with knees directly over the foot.
• Never at any point allow your knees to collapse inward.
• Consider having exercises that help to strengthen the hips and thighs.
Warming up and stretching before engaging in a sporting activity is an important practice in preventing knee injury.
• When training the intensity of the practice ad motion should be done gradually. A sudden increase in intensity can cause strain or harm to the ligaments.

Athletes should at all-time wear comfortable shoes. The shoes should be supporting and fit well on your feet and also be suitable for your sporting activity. Athletes who have issues with foot alignment need to consult their doctor on the appropriate shoe insert they can use to correct the problem.

Football players can ask the sports medicine doctor of the specific shoe cheats that are would serve to reduce the risk of knee injuries.  For sportspersons who engage in skiing, it is advisable to use two mode release bindings; they should be installed and adjusted properly. The boots and binding should be compatible and in a superb working condition.

Female athletes are often advised to have an ACL conditioning program. Such a program will work on balance, agility, and performance drill. It is most applicable in the warm-up phase of training.

• The ACL injury prevention program is recommended to be performed 2-3 times per week. This program should include warming up, stretching, strengthening, plyometrics (jumping and balance drills), agility drills, and cooling down.  The programs will further improve flexibility, balance, and ability to jump and land safely.  The warming up is necessary before starting to play as it will initiate blood to get circulating to muscle and joints as you start the sporting activity.  Stretching will ensure you are flexible enough, make a smooth motion, and maintain a suitable form.

Strengthening can be achieved by doing squats, lunges and other exercises that focus on the thighs and hips. Squatting can be effective when done while standing while the feet are hip-width apart. Then you can sit back while bending from your hips and knees. Stick your buttocks out and let the chest stand high. While squatting always ensure the knees are behind the toes. The knees should always be facing straight ahead as you squat.  Working on exercises that help strengthen the muscles around the back, chest, abdomen, and hips would be a worthy effort in making you become a powerful athlete.

• Injuries to the knee often occur when an athlete is off-balance. When you practice on stability, you will be better balanced in the playing field.  You will need to undertake jumping and landing exercise like jumping and spring while striving to land when the feet and knees are facing straight ahead. Avoid as much as possible not to knock the knees and always ensure the knees are not turning in.  When practicing always ensure the movement are of good quality to avoid the risks of injuries or harm.

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It is always good to take rest. Continuing with practice, games, and activities for a prolonged time might be detrimental in by making the techniques get sloppy and expose you to risks. Taking rest like having rest days, adequate sleep time, and alternating workout are strategies that can ensure there is no injuries and will additionally assist is making you perform excellently in the sports.

Clinical analysis and diagnosis: When to see a doctor

An athlete or any other person who has suffered a runner’s ACL injury should plan to visit a doctor on he or she notices signs or symptoms of the injury. As the knee is a complex joint with bones, ligaments tendons and tissues working together it should be attended immediately to avoid more secondary damage. A doctor will accurately diagnose and determine the severity of an injury and recommend or institute the most appropriate treatment.  In an effort to know exactly what type of injury you have or how it occurred, the doctor can ask a number of questions. Such questions might include:
Inquiring on the type of movement the athlete was having that caused the injury. He or she may want to establish if there was a knee twist, sudden stopping, pivoting, direct contact or a chance of hyperextension.  Asking if there was a ‘pop’ sound when the knee injury happened and how long it took for swelling to appear after the injury.
• Ask if the injury or the severe knee pain sidelined the athlete immediately after its occurrence. The doctor would also need to ask if the knee felt unsteady and could not bear weight after the injury.  If the injury occurred when you were on training or competing sessions, the doctor might need to contact the coach or trainer to have their observation on how the injury occurred or made you react.
• The doctor will then go ahead to examine and compare the injured knee with the uninjured one. He will check for signs of abnormal physical changes, swelling, pain, tenderness, liquid build up inside the knee and possible changes in color. The doctor will test the knees range of motion and see if it is too painful or too swollen.  Pushing through the ligaments is necessary to establish their strength. Your doctor will ask you to bend your knee and then he or she will gently pull forward the lower part of the leg.
When the ligament is torn, the lower leg will have a tendency of moving forward and creating an appearance of an “underbite” or a protruding “lower lip” on the knee joint.  When the lower leg is displaced forward by a large scale from its normal position, then that would mean the damage is greater and the instability is bigger.  When the injury is on a large scale, a doctor can recommend Magnetic resonance imaging scan or conducting a camera-guided surgery (arthroscopy) to offer a clear view of the damaged ACL.
• The partial ACL tears are often diagnosed through arthroscopy.  X-rays can also be utilized to show whether there are some broken bones around the knee area. However, this is not the final diagnostic procedure as X-rays can’t be used to check the soft tissues and like the ligaments and the tendons.  Magnetic Resonance Imaging (MRI) is better placed to view tissues and tendons as it uses radio waves and has a stronger magnetic field. It will be necessary to show the extent of an ACL injury and possible damage to the tissues.  An ultrasound would be necessary as it uses sound waves to visualize internal structures. It is a better and accurate way to show damages to the ligaments, tendons and the muscles around the knee joint.

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When an athlete is suspected to have incurred an ACL injury, it is advisable to use the following measures:
• Place ice on the injured knee for 20 minutes,  find a way to compress the injured area.
• Assist the injured athlete in walking on crutches. The crutches will be important in eliminating pressure on the injured knee and gaining stability
• Raise the leg having an injured knee above the level of the heart,  apply pain reliever and anti-inflammatory drugs.
• Visit a doctor as soon as you can. The doctor will assess the damage and plan on the necessary procedures
• Avoid engaging in sports or other activities when you realize you have a knee injury. More activities may complicate the injury and cause secondary damage.
Other Treatment
An ACL injury is something that can keep you off the track. It is good to seek immediately once you start to feel some excruciating pain in your knee joint. You can also consider visiting your physician once you have an impactful stop, jumping landing or any other event in the field that you suspect might have an impact on your knee. ACL injuries can be treated when long-term damages have occurred.  The first steps of treating An ACL injury involve the RICE rule:
Rest the joint
Ice the injured area to reduce the swelling
Compress the swollen area with an elastic bandage
Elevate the injured area
The doctor might recommend the wearing of a knee brace and administering an anti-inflammatory drug to the athlete. These drugs include Ibuprofen which relieves pain and eases swelling. Upon the subsiding of pain, the doctor will plan for a rehabilitation program for the athlete to help strengthen the muscles around the knee. Rehabilitation will serve to strengthen the knee and stabilize the knee joint and prevent it from more damage.



Surgery might be considered for people in a sporting activity that deals with a lot of pivoting and jumping. The surgery is necessary when the athlete wants to return to the field in the shortest time possible.   Surgery is recommended if:
• The athletic patient wants to return to sport soon
• There is a big damage to the knee. For instance, if it involves more than one ligament or the cartilage in the knee is damaged
• The patient is young and active
• When the injury makes the knee to buckle during the everyday activities

Grade III injury can be treated with RICE, bracing and rehab. But once the swelling subsides, reconstructive surgery can be undertaken using autograft- a piece of your own tissue or allograft- a piece of donors tissue. During the surgery, the doctor inserts surgical instruments and a small camera inside the knee. The camera is then connected to a displaying monitor to enable the surgeon to see all ligaments and tissues in the knee.

The surgeon will also attend to other damages found in the knee. The injured ACL will be replaced with a new one that will become your new ligament. The new ligaments are often attached to the bone through screws or some support devices. The area is then closed by use of stitches and a dressing applied on top. Most of the knee reconstruction is done using arthroscopic surgery. Smaller incisions used in this surgery are known to cause less scarring, unlike the traditional open surgery.

Non-operative treatment

Non-athletes who have an ACL tear in an occasional activity may choose to have rehabilitation and do away with the surgery. Such people are often less active and rare engage in a sporting activity like cutting and pivoting. It is, therefore, common knowledge that such a person will continue to function normally even without the reconstructive surgery.   Sometimes athletes are in a dilemma on using braces or surgery to correct the injury. Sports medical experts have shown that some off-shelf braces may not protect the knee from secondary injuries especially among the athletic or active population. When using the braces, it’s always advisable to involve your doctor who can guide on the best braces to use.


When patients adhere to the rehabilitation program, they have a high chance of fully recovering. 90% of the patients completely recover from the injury. Grade III ACL patients are observed to have a high chance of developing Osteoarthritis around the injured joint knee. A study showed that 50 % to 60% of patients who have had severe knee injury would be having osteoarthritis in 5 years after the injury.


Athletes who have had a runner’s ACL injury may develop knee osteoarthritis. This is a complication where the joint cartilage deteriorates, and the smooth surfaces inside the knee roughen. Patients have a high risk of having arthritis even after having the reconstructive surgery of the ligament. The factors that determine the occurrence of arthritis include the severity of the injury, the presence of related injuries in the knee joint and level of activity after treatment.

The Reconstruction



It is important to note that a patient will resume a session of rehabilitation immediately after the surgery. A week after surgery, the patient will be needed to do gentle motion exercises, strengthening exercises and weight-bearing exercises. With time, the patient can enter into more physical therapies that may include functional movement, advanced strengthening, and balance activities. Such activities should be approved by the treating surgeon to ensure there is no pressure or damage to the earlier injured knee. The exercises are mainly dependent on the severity of the injuries and the complexity of the surgery.
By the fourth month, the patient can consider having a walking or jogging program depending on the level of injury and complexity of the surgery. The athletic patients might be taken through sport related activities like hopping, jumping and agility drills.   After six months, the patient will be able to return to normal activity. The athletic patient can return to the field in eight to twelve months after the ACL reconstructive surgery.

Infection after ACL surgery

Research has shown that an infection can occur during the ACL reconstructive surgery. Mostly such an infection can come with the ACL graft.  Infection after the reconstructive surgery is a rare complication. The chance of getting such an infection is shown by studies to be less than 1%. In this rare occurrence, the infection can occur when bacteria are able to grow inside your body. Small infections can be fought by the immune system, but once they are severe, the system may be incapable of eradicating it. This will call for medical attention.

Infection may occur when joints are susceptible to infection. When there is an infection in the joints, surgery might be necessary to clean it.   When the grafts installed in the knee during surgery have no blood supply, the antibiotics administered to such a patient. This might make the infection to be severe. However, such cases are very rare and can be treated using surgery and administering antibiotics.   The infection can be avoided by ensuring sterile procedure in the hospital operating room, during surgery the patient can be issued with antibiotics. The affected knee might also need to be taken sterilized. You can also ask the doctor of ways to minimize the risk of developing an infection.

Wrapping Up

As with all health concerns, there are many questions to be answered.  Make sure you consult your health care provider before using any information. To assist here are some frequently asked questions to begin your research. Be safe and healthy.

What should an older person do if they get an ACL injury?  Doctors get this common question from older patients. The best thing to do for such a person is to take enough rest as their healing process tends to be slow with the advancement in age. If such a person has a Grade II or Grade III injury, they might need to consider changing their sporting activities and limit themselves from sports that involve cutting and pivoting. Less physical sports would minimize the risk of more injuries or developing complications. Undergoing rehabilitation would also be necessary to have controlled exercises.

How long can one take before returning to sporting activity?
This is dependent on the type of injury one had. Those with severe injuries take longer to heal. The treatment procedure will also have an influence on the time you take before returning to the field. Athletes tend to return to the field soon because they are placed under reconstructive surgery that allows them to heal in real time.

What exercises can minimize the risk of Runner’s ACL injury?
There are activities athletes can undertake to minimize the risk of injury. Such exercises include knee, thighs, and hips strengthening exercises. For instance, an athlete can consider Squats, warm-up, stretching, leg lunges, supervised jumping and landing sessions.

Should I have reconstructive surgery to have my ACL injury treated?
It is not necessary that one go through reconstructive surgery. The surgery is necessary for athletes who want to return to the field soon. For other persons, who are not in sport there are alternative means to attend to the injury. This includes rehabilitative treatment, which works on strengthening the muscles, tendons, and ligaments in the knee.

How can I avoid re-tearing an ACL injury?
This can be avoided by limiting pivoting, forceful landing, bad shoes, pivoting or such activities after you suspect you have an injury. When you have an injury, you should visit your doctor soon to have the situation assessed.




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