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ACL Tear


The ACL is a ligament deep in the middle of the knee that is important in providing stability to the knee while walking, running, and jumping. Ligaments are like leather bands that go from one bone to the other, providing stability to the joint. Without the ACL, there is increased movement between the thigh bone (Femur) and the shin bone (Tibia), causing the knee to be unstable.  This abnormal movement causes abnormal shear forces on the knee, and can often lead to early arthritis.  


The most common symptoms of an ACL tear is pain, swelling, buckling or a feeling of the knee giving out.  Although the unstable feeling may be present with walking, it sometimes is only present when stressing the knee further as in pivoting/cutting movements such as when running and changing direction suddenly.  There are also a small percentage of patients called "copers" who may lead a more sedentary life and do not put enough stress on the knee to notice instability of the knee.  

Dr. Steven Lee will perform a history and physical exam to help determine whether the ACL has been injured.  


Diagnostic Testing

An MRI is usually ordered to not only confirm the diagnosis, but to also look for other pathology that often occurs concomitantly with the ACL injury such as meniscus tears and articular cartilage damage.  



The treatment depends on a number of factors such as the grade/severity of the injury as well as patient factors such as age, activity level, as well as if there is noticeable instability.  There are some patients who may have a partial tear, who are relatively sedentary, and do not have instability with walking, or who are elderly or medically unfit to have surgery, that can be treated with a brace and physical therapy. 

However, most patients with a complete tear of the ACL, and who are relatively young or active will significantly benefit from surgery.  Activities such as running, jumping, or even going down stairs or changing directions suddenly will typically not be able to be performed without an intact ACL.  

While there are exceptions to every rule, most ACL tears cannot be repaired and will usually be reconstructed using a graft, either from your body (autograft) or from a donor (allograft).  Currently the gold standard for this reconstruction is using an autograft.  However, there are times when an allograft may offer a benefit, such as in patients who are over the age of 30, who do not put extreme stresses on their graft as would a professional athlete would or in those patients wishing to have the least amount of pain after surgery, such as those that need to return to work as soon as possible.  

Dr. Steven Lee has performed hundreds of ACL reconstructions, is part of the teaching faculty for the Lenox Hill Sports Medicine Fellowship (which is the oldest sports medicine fellowship in the country), and is currently the Associate Director at NISMAT, which is the first institute in the country dedicated to sports medicine research.  

Learn more about scheduling surgery. 

Postoperative Care

After surgery, Dr. Lee will typically recommend a hinged knee brace that is locked in extension for 4-6 weeks.  During this time, the patient is allowed to bear weight on the leg as long as the knee is kept straight in extension to the level of the patient's comfort.  The reason for this is that the Quadriceps tendon will typically go on strike and not work for the first 3-4 weeks.  Without a functioning Quadriceps tendon, the knee cannot hold up the patient's weight.  

Physical therapy is an important part of the healing process and is started as soon as possible after surgery.  Part of it entails regaining range of motion as soon as possible.  Dr. Lee will often recommend a device called a CPM to help patients regain motion as soon as possible.  Physical therapy can progress for a minimum of 3 months, and full activity, including sports can often be returned back to pre-injury levels by 6 months as long as the motion has returned, and the muscle strength has regained at least 80% of strength compared to the opposite side.  

Immediate Post-Operative Instructions

Please refer to the following pages for more information:


*It is important to note that all of the information above is not specific to anyone and is subject to change based on many different factors including but not limited to individual patient, diagnosis, and treatment specific variables.  It is provided as an educational service and is not intended to serve as medical advice.  Anyone seeking specific orthopedic advice or assistance should consult Dr. Steven Lee or an orthopedic specialist of your choice.


*Dr. Steven Lee is a board certified orthopedic surgeon and is double fellowship trained in the areas of Hand and Upper Extremity Surgery, and Sports Medicine. He has offices in New York City, Scarsdale, and Westbury Long Island. 

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