Ligament Reconstruction

What Is The Acl?

The Anterior Cruciate Ligament is one of the major stabilising ligaments of the knee. It is a strong, rope like structure in the centre of the knee that helps to prevent the knee from slipping out of joint while performing sports and other activities that require pivoting or sudden changes in direction.

When this ligament is torn it does not heal, and this results in a feeling of instability, or giving way, when the individual attempts activities that require pivoting or sudden changes in direction. This giving way can result in further damage to other structures within the knee joint such as the meniscus or articular cartilage.

ACL reconstruction is a commonly performed surgical procedure to create a new ACL to replace the damaged ligament. With recent advances in arthroscopic techniques it can now be performed with a high level of success, minimal incisions, and low complication rates.

How Do You Know It's Torn?

Typically the injury occurs with a twisting movement or sudden change in direction, and is accompanied by a painful “pop” and/or sensation of the knee giving way. Generally the patient is unable to continue playing at the time of the injury. The knee frequently swells, often within a few hours, and there is a sensation that the knee is unstable or weak.


An ACL tear can usually be diagnosed by taking a detailed history of the injury and performing a thorough physical exam. Knee instability can be detected by a skilled examiner by applying specific stresses to the joint.

An Xray will rule out fractures or dislocations, and an MRI will confirm the exact nature of the ligament tear and reveal any associated damage to the cartilage or meniscus within the knee.

Initial treatment consists of simple steps to limit further damage to the knee ie :

  • Rest
  • Ice
  • Compression
  • Elevation

Following this initial period, further treatment depends upon several factors including the activity profile of the individual and the extent of instability they experience. Not everyone requires surgery as some people can compensate for the injured ligament by strengthening the muscles around the knee and avoiding activities which cause the knee to give way. If you have an ACL injury which is not reconstructed it is advised to give up activities which require twisting or pivoting as repeated episodes of giving way that these movements can cause can result in further damage to other structures within the knee such as the meniscus or cartilage. With repeated injuries to these structures arthritis may develop. In those who wish to remain active it is advised to reconstruct the ACL in order to return stability to the injured knee.

Indications for surgery

  • Young patients who wish to remain active
  • Anyone who wishes to participate in sports requiring pivoting or twisting
  • Those with occupations that require a stable knee, or where the knee giving way could be dangerous (eg builders, roofers, etc)
  • Those who are experiencing knee giving way during their day to day activities

The aim of surgery is to return the knee to its normal motion, and to prevent it from slipping or giving way. This is to allow the individual to participate in all their normal sporting activites (including those at the highest level), and to avoid further damage to other structures within the knee that can occur with repeated giving way.

When Should Surgery Be Done?

ACL reconstruction is an elective (not emergency) surgery and does not have to be performed immediately. In fact, it is generally advisable to wait for several days or weeks until swelling has resolved and range-of-motion has returned to normal. This will make recovery from surgery much easier and reduce the risk of complications. Physical therapy may be recommended prior to surgery. If the knee is “locked” due to cartilage tears or if there is other ligament damage, the surgeon may advise earlier surgery.

What Does Surgery Involve?

Improvement in surgical techniqes for ACL reconstruction in the past 10 years have resulted in surgery that is more successful, less painful, and with shorter recovery times than in the past.

The majority of the surgery is performed arthroscopically (“key hole”) using specialized instruments to access the centre of the knee. Firstly a small incision is made adjacent to the knee to identify the hamstring tendons which will be fashioned into the ligament graft that will be used to reconstruct the damaged ACL. Occasionally the central part of the patella tendon at the front of the knee may be utilized instead. Tunnels are drilled in the femur and tibia where the old ACL was attached and the replacement graft is then pulled through these tunnels and attached to the bone at each end.  Depending on the type of graft, it may be attached using screws, staples or other fixation devices. These act to hold the graft solidly whilst it heals into the tunnels.

At the time of the surgery the arthroscope allows the entire knee to be clearly visualized, and any other damage, such as cartilage or meniscus tears will also be repaired at the same time.

Click here to see Dr Fritsch perform an ACL reconstruction.


Surgery is performed either as a day only procedure, or with a single overnight stay. You will be able to walk immediately taking the full weight on your leg. Crutches are used for the first 7-10 days in order to help regain your normal walking pattern at the fastest possible rate. A brace is generally not required, and simple tablet painkillers are usually sufficient to control any discomfort. You will begin physiotherapy few days after surgery and continue this for between 3 and 6 months after surgery. Please refer to Dr Fritsch’s ACL rehabilitation protocol for more specific instructions regarding rehabilitation.

What Are The Risks Or Possible Complications Of Surgery?

Although rare, complications or adverse reactions can occur with any surgical procedure. These may include:

Adverse or allergic reactions to medications or anaesthetics.

Infection (<1% risk)

If this occurs it can be treated with either tablet or IV (through a drip) antibiotics. Rarely a further operation is required to wash the infection out of the joint. You will be given an antibiotic through the IV during your surgery to reduce the risk of infection.

Blood clots in the leg.

These are rare but if they develop will cause severe calf pain & swelling. IN some instances it is possible that the clot detaches from the leg vein and travels to the lungpossible embolus. Though extremely uncommon after ACL surgery this can cause serious consequences including death. Early mobilization to encourage circulation in the leg will help prevent this and if a blood clot does occur, you would need to take a “blood thinner” medication for several months.

Nerve damage

Some temporary skin numbness is normal around any incision as there are tiny fibres in the skin which cannot be avoided. Permanent nerve damage is rare and if it does occur post ACL surgery it is most often a small area of numbness that does not cause any significant disability. Very rarely there can be injury to the more important nerves or blood vessels of the leg resulting in weakness.

Joint stiffness

Scar tissue can form inside the knee (arthrofibrosis) leading to loss of motion. Advances in surgical technique and early physical therapy generally prevents this, but stiffness can still be a problem in a small percentage of cases.

Graft rerupture

In the same way the normal ACL can be ruptured, the reconstructed ligament can also retear. The retear rate is approximately 1% per year per knee, and if it does occur it can be reconstructed again using alternative tendon grafts.

Donor site pain

This refers to pain from the area where the graft tissue was obtained from (hamstrings/patella tendon). It is generally minimal and settle over time, though it is slightly more common when the patella tendon is used (thus the hamstring tendons are the first choice in most cases).

Whilst these complications are quite uncommon after ACL reconstruction it is important to realize that all surgery does have inherent risks. This list gives an outline of the possible complications, but please feel free to ask as many questions regarding your surgery as you need to be comfortable with the procedure. All care is taken to avoid these complications and in most cases the outcome is very successful

When Can I Return To Sports?

With normal progress, you can expect to return to sports activity 4 to 5 months after your surgery with a return to full sporting activites between 6 and 9 months post-op.


Anterior Cruciate Ligament reconstruction is a common and successful procedure which can return the majority of patients with this injury to full activity. Success is a combination of precise surgical technique and appropriate rehabilitation, and in the hands of an experienced surgeon the vast majority of patients can expect an excellent outcome.

The above information gives an overview of the common issues relating to this procedure. It is aimed at educating you about what is involved in ACL reconstruction. If you have any further questions please consult with your treating surgeon.

Click here to see Dr Fritsch perform an ACL reconstruction.

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