ACL Reconstruction Surgery

When the anterior cruciate ligament (ACL) is torn, it lacks the ability to heal itself.

How is the ACL injured?

The ACL ligament resists forwards movement and rotation of the tibia (shin bone) underneath the femur (thigh bone).  When it is stressed beyond it’s ability to resist, the ligament ruptures. This usually occurs with sudden changes of direction or speed when running or landing from a jump. In New Zealand, sporting accidents are responsible for the majority of ACL injuries.




Who needs ACL reconstruction?

Some people can cope without an ACL reconstruction, especially if they aren’t involved in pivoting sports, such as netball or rugby.  For these people, a guided rehabilitation program, followed by a gradually increasing activity, will enable them to get back to an active lifestyle.

However, if you want to participate in high-demand pivoting sports, or are experiencing ongoing episodes of instability, the usual treatment recommended is surgical reconstruction of the ACL.

This surgery involved transferring another tendon into the knee, as a substitute for the torn ACL. Most commonly hamstring tendons or a portion of the patella tendon is used.

Surgical Procedure

Surgery is only the first step in successful ACL reconstruction. Much of the outcome depends upon your participation in a rehabilitation program, both before and after surgery.

All surgery carries risks. Usually ACL reconstruction surgery is safe and routine. The likelihood of a life-threatening complication, damage to major blood vessels or nerves is very rare and unusual.  However there are specific complications, such as numbness on the shin, kneeling pain and the risk of reinjury.




When can I return to work?

Return to sport and work depends on a number of factors to do with your particular activities as well as how well your rehabilitation is progressing.

In general terms:

  • Sedentary work after 1-2 weeks
  • Light duties, involving being on your feet for a prolonged period after 4-6 weeks or so
  • Moderate duties involving carrying loads on uneven ground, climbing ladders etc after 2-3 months
  • If you have very heavy duties, or those requiring agility on uneven ground, you may not be able to get back to full duties for 4 months or more.


Returning to sport

An ACL injury is a potentially career-ending injury for an athlete. The best hope for returning to pivoting sports is with ACL reconstruction combined with a comprehensive rehabilitation.

In general terms, low resistance cycling may commence after 1-2 weeks, jogging after 3 months. It usually takes a minimum of 9 months to get your knee strength and muscle control back to an adequate level for a full return to contact or pivoting sports.

When we assess athletes who have had ACL reconstruction 90% of them have normal or near-normal strength, stability and movement. In spite of this, only 2/3 return to competitive sport, with less than half returning to their pre-injury level of sport.



What are the risks of re-injury?

The risk of re-injury following ACL reconstruction varies but can be greater than 10% in some groups of patients.  Reinjury risk is increased in:

  • Young athletes, especially those <20 years old
  • Participation in high-demand pivoting or contact sports (for example: soccer, netball or rugby)
  • Early return to sport
  • Inadequate knee rehabilitation

Because of this risk, we strongly recommend that all athletes who have been treated for ACL injury undergo a comprehensive rehabilitation program following surgery. A return to sport assessment should be completed by an experienced physiotherapist or your treating surgeon prior to participating in high-demand sports.




This information is a general guide only and is not a substitute for expert medical opinion from your treating health professional. If you are considering having an ACL reconstruction, you will need to discuss your suitability for surgery and the specific risks with your surgeon.