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Anterior Cruciate Ligament (ACL) Reconstruction

Anterior cruciate ligament injuries occur most often in the sporting population.
A torn anterior cruciate ligament is a common outcome from a major knee
injury. The anterior cruciate ligament is the primary stabiliser of the knee
joint. Thigh and calf muscles are secondary stabilisers of the knee joint.

If you have torn your anterior cruciate ligament you usually have a sudden
twisting movement with your leg fixed on the ground. A snap or pop may be
heard and the knee usually swells up within a few hours. The ligament either
snaps in half or is pulled from the femoral or tibial surfaces. Once completely
torn the ligament cannot repair itself. Partial tears may heal but the tendon
is often stretched causing the knee to give way. The anterior cruciate ligament
rupture will cause the knee to become unstable in certain movements. This occurs
usually when one pivots such as a sudden change in direction. The knee feels like
it is going to give way.

At the time of injury the other ligaments and cartilages in the knee may
be damaged. Most commonly the medial collateral ligament may tear and
either the medial or lateral meniscus may tear. This may result in locking
of the knee joint.

Initial treatment is important to reduce swelling and improve range of motion
by appropriate exercises. An x-ray is taken to exclude a fracture and
occasionally an MRI scan is arranged to further assess the knee joint. It
is quite common to see bone bruising on the MRI scan.

An anterior cruciate ligament reconstruction is recommended in patients
whose knees give way on repeated occasions. If you have built up your thigh
muscles and your knee does not give way then an anterior cruciate ligament
reconstruction may not be necessary. There is a theoretical argument to
do an anterior cruciate ligament reconstruction in order to preserve the
knee for the future. It has been proven that torn cartilages result in long-term osteoarthritis. It is yet to be proven that a torn anterior cruciate ligament
results in osteoarthritis but a torn anterior cruciate ligament with an unstable
knee may lead to a torn cartilage and therefore in the end, an arthritic knee. Reconstructing the anterior cruciate ligament may not prevent long-term
arthritic changes.

The surgery:

Two methods of anterior cruciate ligament reconstruction are available. The
first method uses the central third of the patellar tendon and the second
method uses the hamstring tendons from behind the knee. Both methods
have advantages and disadvantages and you should discuss with your
surgeon his preferred method.

The following steps outline the surgical procedure in anterior cruciate
ligament surgery:

  1. General anaesthetic.
  2. Hamstring or patellar tendon harvesting and preparation.
  3. Arthroscopy to clean up the knee joint, trim or repair any torn
    cartilages and prepare the femoral and tibial bone tunnels.
  4. The graft is passed through the tunnels and secured either with
    screws or staples.

Following anterior cruciate ligament reconstruction it is important to have a
regular physiotherapy exercise programme in order to rehabilitate the knee
and regain motion. It is most important to regain full extension.

Risks and complications:

General anaesthetic risks.

As anybody undergoes general or regional anesthesia (epidural anesthesia)
there are always risks associated with it. The risks of course are magnified if
you have abnormal general medical conditions, which may have affected the
functions of your vital organs such as heart, lungs and kidneys. Therefore a
complete evaluation of those systems has to be performed before you are
taken to the Operating theatre.

Specific risks:

  1. Infection.
  2. Deep vein thrombosis.
  3. Numbness just to the side of the incision.
  4. Stiffness.
  5. Reflex sympathetic dystrophy.
  6. Rupture of the graft.
  7. Damage to vessels and nerves.
  8. Ongoing instability and pain.


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