ACL (cruciate) tears: surgery or not?

Sports fans recognise this gut-wrenching scenario.   A football match is being televised when, suddenly, the action stops. A young athlete is on the ground  clutching their knee.  The replay shows that they  were brought down by a knee twisting action perhaps from a tackle or landing awkwardly from a mark. Commentators begin to speculate on whether they have ‘done their cruciate.’ Or perhaps: done it again.  Even before  the unfortunate young athlete is carted off,  the commentators are  pondering  how long  it will take them to get back to play after  reconstruction surgery. If they are to be believed, surgery is inevitable.

The  Anterior Cruciate Ligament (ACL) runs from the front of the top of the tibia (shin bone) to the back  of the femur  (thigh bone) within the knee joint.  It crosses the posterior ligament, hence the name cruciate (meaning a cross). The  cruciate ligaments are  part of the knee stability and proprioceptive (balance) complex that also includes ligaments, tendons, and muscles. The ACL’s main job is to help  stop the tibia  sliding  forward.  If   ruptured, a clinician can pull the lower leg further forward on the thigh than is normal, using what is  called an ‘anterior  draw  test.’ However, this test does not always explain function  [1] because the knee does not depend on the ACL alone for stability. I have seen young athletes with  a positive draw  test, (meaning thay have a ruptured ACL) but no problems playing sport or skiing (yes: really).

The belief that the cruciate ligament is essential for stability has, however, led many young athletes to surgery. Worldwide, the  number undergoing ACL surgery  is  increasing with  Australia in the lead[1].  Especially worrying (as I have written previously)  is the increasing  rate of knee surgery on children (1). Some blame this on Australia’s love of risky sports: for example, ACL tears are   a  common problem for young women playing  Australian Rules football, a contact sport. Our  belief that  tendons and  ligaments  alone are responsible for stability and the pressure on young athletes (including children) to undergo surgery  to fix them, undoubtedly   contribute to high numbers.

However, there is NO evidence that surgery is  more helpful than exercise rehabilitation [3].  1 in 5 suffer reinjury to either the repaired or other knee after surgery [4].  Around 10-15% of surgeries ‘fail’ in  the    short-term   while  long-term, failure may be as  high as 27% [5, 6].  Problems after surgery can also  include  tightness, loss of proprioception (balance) [7]  recurring inflammation and arthritis [8, 9].

However so called ‘conservative’ treatment that includes exercise (rather than surgery) or rest to promote healing is, unsurprisingly, controversial with surgeons. One surgeon,  quoted in the NBC health news**,  said it was ‘malpractice’. Strong words but there  is no convincing  evidence that surgery prevents long term pain/arthritis as is claimed [9, 12, 13].

For   years now,  the Swedish KANON trials  have been investigating whether  exercises that retrain  agility, balance, proprioception and  strength can be more effective, with less side effects, than surgery, and/or  can help surgical outcomes [10, 11].   One recent  KANON study, led by Dr Stephanie Filbay  from  the Centre for Health, Exercise and Sports Medicine (CHESM) at the University of Melbourne,   found that 90% of ACL tears in 80 participants (mostly athletes) showed signs of healing  after non- surgical  treatment [12]. The team used  a brace  to keep injured  knees  bent to  90 degrees to  help the torn ends of the ACL  fuse and heal.  Patients then had  physiotherapy for two months while  the  braces were slowly adjusted to allow more movement. Braces were removed after  three-months. MRIs  taken  then and again at six months, showed that most ACLs repaired themselves. Many participants  reported good knee stability and function,  and were able to return to their sport a year later [14].

According to  CHESM,  not all ACL tears are equal:  the degree of damage is a  factor in recovery or decision whether to undergo surgery  [3, 15].  They  have put out a helpful, on-line, guide to treatment options which, at the very least, suggest an exercise rehabilitation trial before any surgery.   I agree. Why not?  ​Even if you or your  patient decides to go ahead with surgery, it can only help. This  what they have to say:

‘Postponing the decision to have surgery does not result in worse outcomes compared to having surgery right after the injury [3] . ​

Research suggests that performing rehab for 1 to 6 months before surgery improves knee strength and function after surgery.

Two clinical trials conducted in Europe have shown that around 50% of people who start rehab with the option of having surgery later on, decided to have ACL surgery within two years.  These people included those who had a strong preference for surgery before the studies, and those who decided to enrol into the study so that they could bypass the waitlist for surgery. On the other hand, 50% of people in these trials were satisfied with the outcome of rehab without surgery.’ (https://www.aclinjurytreatment.com/treatment-options)

This means that it is very hard to find ‘good’ unbiased partipants given society’s strong beleif in surgery. However, despite this, half of those  in the trial  regained functional stability without surgery. 

I would add that the catch is, and this applies to those undergoing surgery as well, exercises must be kept up. Once prone to this injury, or pain related to it, chances are  you will be again WHETHER OR NOT SURGERY IS UNDERTAKEN [16].

So, take time and do the careful FULL rehab  before returning to sport to minimise long term problems [17]. Once a good neuromuscular exercise routine is established, keep at it. This should not be onerous.  Do not wait for pre-season training (a danger time for knees).  Know when muscles need time out. Or reconsider if the sport carries too high a risk of injury. This is a life sentence to helpful exercise, good match preparation, and sensible play,  not pain!

References

 1. Smith, T., et al., Is reconstruction the best management strategy for anterior cruciate ligament rupture? A systematic review and meta-analysis comparing anterior cruciate ligament reconstruction versus non-operative treatment. The Knee, 2014. 21(2): p. 462-470.

2. Zbrojkiewicz, D., C. Vertullo, and J.E. Grayson, Increasing rates of anterior cruciate ligament reconstruction in young Australians, 2000–2015. Medical Journal of Australia, 2018. 208(8): p. 354-358.

3.          Saueressig, T., et al., Primary surgery versus primary rehabilitation for treating anterior cruciate ligament injuries: a living systematic review and meta-analysis. British Journal of Sports Medicine, 2022. 56(21): p. 1241.

4.          Barber-Westin, S. and F.R. Noyes, One in 5 Athletes Sustain Reinjury Upon Return to High-Risk Sports After ACL Reconstruction: A Systematic Review in 1239 Athletes Younger Than 20 Years. Sports Health, 2020. 12(6): p. 587-597.

5.          Crawford, S.N., B.R. Waterman, and J.H. Lubowitz, Long-term failure of anterior cruciate ligament reconstruction. Arthroscopy, 2013. 29(9): p. 1566-71.

6.          Bach, B.R., Jr., Revision anterior cruciate ligament surgery. Arthroscopy, 2003. 19(10): p. 14-29.

7.          Fleming, J.D., R. Ritzmann, and C. Centner, Effect of an Anterior Cruciate Ligament Rupture on Knee Proprioception Within 2 Years After Conservative and Operative Treatment: A Systematic Review with Meta-Analysis. Sports Medicine, 2022. 52(5): p. 1091-1102.

8.          Lien-Iversen, T., et al., Does surgery reduce knee osteoarthritis, meniscal injury and subsequent complications compared with non-surgery after ACL rupture with at least 10 years follow-up? A systematic review and meta-analysis. British Journal of Sports Medicine, 2020. 54(10): p. 592.

9.          Webster, K.E. and T.E. Hewett, Anterior Cruciate Ligament Injury and Knee Osteoarthritis: An Umbrella Systematic Review and Meta-analysis. Clinical Journal of Sport Medicine, 2022. 32(2).

10.        Frobell, R.B., et al., A randomized trial of treatment for acute anterior cruciate ligament tears. New England Journal of Medicine, 2010. 363(4): p. 331-342.

11.        Frobell, R.B., et al., Treatment for acute anterior cruciate ligament tear: Five year outcome of randomised trial. BMJ (Online), 2013. 346(7895).

12.        Harris, K.P., et al., Tibiofemoral Osteoarthritis After Surgical or Nonsurgical Treatment of Anterior Cruciate Ligament Rupture: A Systematic Review. Journal of Athletic Training, 2017. 52(6): p. 507-517.

13.        Ekås, G.R., et al., Evidence too weak to guide surgical treatment decisions for anterior cruciate ligament injury: a systematic review of the risk of new meniscal tears after anterior cruciate ligament injury. British Journal of Sports Medicine, 2020. 54(9): p. 520.

14.        Filbay, S.R., et al., Healing of acute anterior cruciate ligament rupture on MRI and outcomes following non-surgical management with the Cross Bracing Protocol. British Journal of Sports Medicine, 2023. 57(23): p. 1490.

15.        Filbay, S.R., et al., Delaying ACL reconstruction and treating with exercise therapy alone may alter prognostic factors for 5-year outcome: an exploratory analysis of the KANON trial. British Journal of Sports Medicine, 2017. 51(22): p. 1622.

16.        Filbay, S.R., et al., Quality of life in anterior cruciate ligament-deficient individuals: a systematic review and meta-analysis. British Journal of Sports Medicine, 2015. 49(16): p. 1033.

17.        Van Ginckel, A., P. Verdonk, and E. Witvrouw, Cartilage adaptation after anterior cruciate ligament injury and reconstruction: implications for clinical management and research? A systematic review of longitudinal MRI studies. Osteoarthritis and Cartilage, 2013. 21(8): p. 1009-1024.

See also  

** Katie Camero and Jessica Herzberg: https://www.nbcnews.com/health/health-news/knee-injury-acl-treatment-heal-surgery-rcna99606

https://www.abc.net.au/listen/programs/healthreport/acl-injuries-on-the-rise-among-young-australians/9686810

https://www.abc.net.au/listen/programs/melbourne-afternoons/knee-reconstruction/104230784

Check out the CHESM site for assistance with decisions:

https://www.aclinjurytreatment.com/treatment-options

Photo: Getty Images

Nb: updated Feb 2025

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