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Preventing ACL graft re-ruptures and ensuring safe return to sport

There has been a fair amount of press lately surrounding Australia’s alarmingly high rate of anterior cruciate ligament (ACL) tears amongst our active and sporting populations. Surgery combined with physiotherapy and sports-specific strength and conditioning remains the staple treatment to ensure a safe return to sport.

Deciding when it is safe for you to return to your chosen sport, whilst more importantly, ensuring you do not re-rupture you new ACL (or also commonly the opposite ACL!) and ruin all their hard work, are two of the biggest challenges facing patients and athletes alike. Whilst the standard 9-12 months recovery guideline is a decent timeframe in terms of tissue and surgery healing, it does not address the various functional demands specific to your sport.   

Once you return to your chosen sport, there are some surprising stats from the research:

the risk or re-rupturing the repaired ACL can be up to 1 in 4 (Wright et al, 2007)

the risk of rupturing the ACL on the non-operated knee can be up to 1 in 5! (Wiggins et al, 2016)

The average time from the player returning to sport until re-rupture is 105 days (Kyritsis et al, 2016)

Alarmingly, for those who do have ACL surgery, 81% return to some form of sport, 65% return to their pre-injury level of sport, and only 55% return to competitive sports (Arden et al, 2014).

Research has identified some key findings that can increase the risk of re-damaging your ACL. These include:

  • Poor neuromuscular control and strength between the quadriceps and hamstrings muscles,
  • Insufficient balance, agility and co-ordination for the desired sport,
  • Being a younger athlete compared to being an older athlete,
  • Being male compared to female, and
  • Playing sport at the elite level.

So what can physio’s do to ensure not only you return to your desired sport, but also safely without risk of re-injury? A collection of tests can give very accurate information about your progress whilst guiding your rehabilitation team in deciding when it is safe for you to return to sport. Kyritsis et al, 2016 have found the six biggest tests that give us the most confidence are:

Return to sport test

Discharge with confidence when these criteria are met

Quadriceps-hamstring strength testing

Quadriceps strength deficit <10% at 60o

Single hop

Limb-symmetry index >90%

Triple hop

Limb-symmetry index >90%

Triple crossover hop

Limb-symmetry index >90%

On-field sports-specific rehabilitation

Fully completed

Running t-test

<11 seconds


What does this all mean? These tests show to the physio that your knee is functioning back to the same level – or marginally close to the same level – as your non-operated knee BEFORE you injured it. Also if your weights you are lifting are at the same level prior to your surgery, and your various field drills and agility requirements are back to or close to baseline, you can be confident that the risk of damaging your ACL is VERY minimal. Other questions to address can include:

  • Do I have the same level of fitness and conditioning before my injury?
  • Have I completed enough field training sessions to ensure I am confident enough to return to playing sport?
  • Do I have any concerns or worries before I play sport again?

Our job as physio’s is to ensure you get back to playing the sport that you love without re-injuring yourself. If we use the above six tests, combined with sport-specific assessments, both yourself and your physio can be confident that your knee has the strength and robustness to handle what your sport demands of it.


Arden CL, Taylor NF, Feller JA, Webster KE. Fifty-five per cent return to competitive sport following anterior cruciate ligament reconstruction surgery: an updated systematic review and meta-analysis including aspect of physical functioning and contextual factors. Br J Sports Med 2014; 48: 1543-1552.

Kyritsis P, Bahr R, Landreau P, Miladi R, Witvrouw. Likelihood of ACL graft rupture: not meeting six clinical discharge criteria before return to sport is associated with a four times greater risk of rupture. Br J Sports Med 2016; 50: 946-951.

Wiggins AJ, Grandhi RK, Schneider DK et al. Risk of secondary injury in younger athletes after anterior cruciate ligament reconstruction: a systematic review and meta-analysis. Am J Sports Med. Published online first: 15 Jan 2016.

Wright DW, Dunn WR, Amendola R et al. Risk of tearing the intact anterior cruciate ligament in the contralateral knee and rupturing the anterior cruciate ligament graft during the first 2 years after anterior cruciate ligament reconstruction: a prospective MOON cohort study. Am J Sports Med 2007; 35: 1131-4.

By Zach McKay