Knee > ACL Tear > Treatments


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Non-operative treatment for ACL (anterior cruciate ligament) tears may include the use of a brace in conjunction with exercises designed to strengthen the muscles around the knee. Instead of relying on the ACL for support, you will need strong hamstring muscles in the back of your thigh and quadriceps muscles in the front of your thigh to stabilize your knee so it can support your weight. Your physician may initially prescribe a rehabilitative knee brace, designed to stop your knee from flexing past a certain point. These stiff, light-weight braces are restrictive but allow some motion. As you regain strength and stability in the knee, your physician may recommend a functional knee brace, which is more flexible and designed to be worn during daily activities. You need to reduce two main forces from stressing your knee during rehab and daily activities: rotation (the shinbone and thighbone twisting in opposite directions) and translation (the shinbone moving forward in relation to the thighbone).


Off-the-shelf functional knee braces are sized according to the circumference of your thigh six inches above your kneecap. Custom braces are fit by measuring your thigh, knee, and calf with an instrument provided by the brace manufacturer. Choose the longest possible brace that fits without restricting your movement. More durable brace materials are more important if you plan on being active. Be sure a physician trains you to position the brace hinges around your knee so it bends normally. Check the brace's position regularly and reposition the brace if it slips. Do not rely on the brace for support. Be cautious when moving and be prepared to limit your involvement in physical activities. There is no evidence that wearing a brace prevents injury.


You will likely feel pain and discomfort for the first few days after the injury, and your doctor will prescribe pain medications as needed. These will likely be mild, over-the-counter painkillers such as ibuprofen or acetaminophen. Rest your knee as often as possible, elevating it above your heart level, and icing it for between 20 and 30 minutes a few times a day to reduce pain and swelling. As soon as possible, you should begin using a CPM (Continuous Passive Motion) machine while in bed. Your physician usually can arrange to get you a CPM. This flexes and extends the knee and prevents the joint from becoming stiff due to inactivity. You are encouraged to begin walking and putting some weight on your knee immediately with the aid of crutches and a rehabilitative brace. You may need to use crutches for between two days and three weeks. Within two weeks, the majority of patients should be able to walk carefully without crutches. Be careful to avoid activities that put your knee at risk. Anything in which you might twist your knee can lead to further injury. With proper physical therapy, people who lead more sedentary lives can often return to work within a week, and after four or six weeks most can resume driving then. More active people may need more time to recover before returning to work.


Your physician may prescribe visits to a physical therapist to begin supervised strengthening exercises as soon as possible after your orthopedic evaluation. Non-operative recovery from a torn ACL takes an average of between four and six months with 45-minute exercise sessions three days a week. Though everyone's rehab program is slightly different, physical therapy for a torn ACL follows a general pattern. The first three weeks are usually spent restoring a full range of motion to your knee and recovering to the point of being able to walk without crutches. Movement may initially be painful, but it is important to not allow your knee to stiffen. Rehab progresses to resistive exercises to strengthen muscles around the knee. During this time, you should be able to resume functional activities like stair climbing, single leg support, swimming, and driving. After about three months, the emphasis will change from strengthening to functional training, as you begin exercises ­ specifically geared for your activities and lifestyle ­ to regain balance and control over your body. These may include more vigorous warmups on a stationary bike, elliptical trainer, or treadmill. You should be able to return to normal activities after about four months. Physicians usually suggest that you continue strength training even after your knee has been rehabilitated. Your doctor will likely check your ACL for strength and endurance. After your physician measures knee strength, you may be able to exercise at full strength and compete in your favorite activities. However, your ability to exercise may remain limited to walking and light activity even after rehabilitation. If your knee continues to buckle and remains unstable after rehab, non-operative treatment of your ACL tear may not have been effective. You should consult your physician about undergoing a more aggressive treatment.


   Knee strengthening exercises: Ligament injuries

Prevention [top]

Strengthening the hamstrings and quadriceps muscles will help prevent further knee injury. The more agressive and dedicated you are during rehab, the greater ther chance you will maintain a stable knee. After up to six months of rehab, your knee may feel strong but your will not help stabilize you knee as it did before the injury. You may be vulnerable to further injury. Many of the exercises and activities that are popular for fitness put stress on your knees. To prevent further ACL injuries it is important to learn knee-sparing exercise techniques by dividing your activities into three components:

   Daily living - the average person takes between 12,000 and 15,000 steps a day, exerting a force between two and five times your body weight on your knees. After a knee injury, take it easy on your knees during the day whenever possible to save them for activities and exercise. Avoid stairs when there is an elevator, take the shortest path when walking, and consider wearing athletic shoes designed to absorb shock.

   Muscle strengthening/conditioning - activities themselves are not a substitute for conditioning. It is essential to adhere to the muscle strengthening program you learned in rehab throughout the remainder of your life. The best strengthening programs are low-impact and non-weight-bearing, like stationary bikes and certain weightlifting programs, so that the knees do not have to absorb shock.

   Recreation - your sport or activity of choice helps maintain mental and physical well-being, but it is not a conditioning program. Sports that require twisting and quick direction changes put great strain on your knee. Without surgery to repair your ACL, you should avoid sports like basketball, soccer, skiing, running, and football that stress your joint.

PAIN [top]

A small amount of pain is normal during physical activity, but if you feel so much pain in your knee to warrant taking a painkiller before an activity, you should consider cutting back or stopping. Do not play through the pain after an ACL injury - it may be a sign that your activity is putting too much stress on your knee.


Some people feel safe wearing a knee brace after an ACL injury, but if the brace is too tight, it can cause added pain afterward an activity. If you do wear a brace, wear one that has a kneecap hole or padding. There is no evidence that braces prevent injuries, meaning they are not a substitute for increasing your muscle strength. Always consult your physician before buying a knee brace.

Physical Therapy
   Home Recovery
Reconstruction: Bone-Patellar Tendon-Bone Autograft or Allograft
Reconstruction: Quadrupled Hamstring Autograft or Allograft
Reconstruction: Quadriceps Tendon Autograft or Allograft

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