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ACL Surgery Risks

As with any surgery, there are potential risks involved in ACL reconstruction. The decision to proceed with the surgery is made because the advantages of surgery outweigh the potential disadvantages.

It is important that you are informed of these risks before the surgery takes place.

Complications can be medical (general) or surgical complications specific to the knee.

Medical complications

Medical complications include those of the anesthetic and your general well being. Almost any medical condition can occur so this list is not complete. Complications include:

  • Allergic reactions to medications

  • Complications from nerve blocks such as infection or nerve damage

Surgical complications


Infection can occur with any operation. In the knee, this can be superficial or deep. Infection rates are approximately 1%. If it occurs, it can be treated with antibiotics but may require further surgery. Very rarely your ACL graft may need to be removed to eradicate infection. Tom Brady underwent ACL reconstruction and had a serious infection. This required reoperation; as is the typical case, the final outcome was positive (he subsequently was the MVP in the NFL!!)

Blood Clots (Deep Venous Thrombosis)

These can form in the calf muscles and can travel to the lung (Pulmonary embolism). These can occasionally be serious and even life threatening. If you get calf pain or shortness of breath at any stage, you should notify Dr. Pearle, your medical doctor, or go directly to the Emergency Room.

Fractures or Breaks in the Bone

Fractures or breaks can occur during surgery or afterwards if you fall. To repair these, you may require surgery.

Stiffness in the Knee

Ideally, your knee should bend fully but on occasion, may not bend as well as expected. It should also straighten fully. Occasionally, further surgery is needed to remove the scar tissue and restore motion.

ACL graft failure

ACL graft failure rate is varies with the age of the patient. Recent studies have shown a rerupture rate in teenages of approximately 10% but it drops to approximately 1-2% as we get older.

Wound Irritation or Breakdown

The operation will always cut some skin nerves, so you will inevitably have some numbness around the wound. This does not affect the function of your joint. You can also get some aching around the scar. Vitamin E cream and massaging can help reduce this.

Occasionally, you can get reactions to the sutures or a wound breakdown that may require antibiotics or rarely, further surgery.

Damage to Nerves and Blood Vessels

Rarely these can be damaged at the time of surgery. If recognized they are repaired but a second operation may be required. Nerve damage can cause a loss of feeling or movement below the knee and can be permanent.

Further Surgery

Further surgery for meniscal tears and scar tissue removal can be required after ACL reconstruction.


ACL tears are associated with the development of knee arthritis over the long term. It is currently unclear whether ACL surgery prevents the future development of arthritis.


Surgery is not a pleasant prospect for anyone, but for some people with ACL injury, it could mean the difference between leading a normal life or putting up with a debilitating condition. Surgery can be regarded as part of your treatment plan-it may help to restore function to your damaged joints as well as relieve pain.

ACL surgery is one of the most successful operations available today. It is an excellent procedure to improve the quality of life, return to cutting sports, and improve function.

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