Anterior Cruciate Ligament (ACL) injuries: A general overview

Anterior Cruciate Ligament (ACL) injuries: A general overview

Since I was on the topic of Anterior Cruciate Ligament(ACL) injuries in the adolescent female last week, I would like to broaden the scope and cover some more grounds on ACL injury. This time, my attention is on the rates of ACL injuries, how many people actually return back to sport after an anterior cruciate ligament reconstruction (ACLR), patello-femoral joint (PFJ) pain during rehabilitation, and some Return to sport (RTS) outcome measures that should be “non-negotiable” when deciding on return to play.

A case study performed on 242 patients – all under the age of 18 years-old – who underwent primary ACLR, found that 75 (30%) had sustained another injury to their surgical graft, or to their opposite ACL, or both within 15 years of having the primary surgery performed.1 Taking a wider look across an older age group it appears that as we get older, the success of primary ACLR is marginally better. A systematic review and meta-analysis of 1004 patients (mean age 30 years, 66% male) found that within 2 years of primary ACLR, 13.5% had failed.2 Another review found that 12% of primary ACLR will fail at least 10 years follow-up.3

Key message – Surgery is not always 100% successful. The key period of rehab is obviously the first 12 months post-operatively, but on-going regular strength and conditioning (2-3 x per week) is essential whilst the person is still playing sport.

In regards to Return to Sports (RTS), the number of people that RTS following ACLR is really surprising. One study in particular found that 81% of people will return to any sport, 65% had returned to pre-injury level of sport, and only 55% of people had returned back to competitive sport.4 In a study by the same authors, they found that less than 50% of people went back to competitive sport within 2-7 years following ACLR.5

Key message – Be realistic with your patient/athlete that there is a high chance that they won’t return to their pre-injury or competitive level of play after their ACLR. And that is totally OK. Life, work and family often take priority. Do encourage modified exercise options though, for on-going general health and well-being.

Following on from this, in regards to actual clearance from the medical team to RTS, it is very surprising to read that only 13% of 264 studies on ACLR used objective outcome measures to decide if a person was ready to r eturn to sports. Even more worrying was that 40% of the studies did not report any outcome measures, and 32% of the studies found that patients were being cleared to RTS based purely on post-operative time frames.6 With this information, it is no wonder why we have such high re-injury rates. Of course, clinical tests carried out by the treating orthopedic surgeon are of absolute importance – i.e. absence of swelling, full knee active range of motion, negative Lachman’s test and a negative pivot-shift test – but I think a marriage of both clinical tests and functional tests are essential before the athlete returns to play. I have provided a link to a paper that provides a very clear criterion-based progression from ACLR through to RTS, and I feel that we should all be using this model (or one very similar to it) with all of our ACLR patients/athletes.

Key message: Use objective measures to determine if your patient is ready to return to sports. Don’t just assume that they are ready to RTS after 12 months.

Lastly, this is one particular area that I feel very strongly about, so forgive me in advance if I get a little bit “ranty”, but PFJ pain should not be viewed as “collateral damage”  during ACLR, particularly during the first 1-2 months post-op. I’ve seen one too many patients advised to push through the pain, only for them to have a very slow recovery and poor overall outcome. In my opinion, PFJ pain is a sign that rehab has been inadequate and the vastus medialis oblique, glute medius and the hamstrings on the operated leg still need A LOT of work.

There has been some very interesting research performed on the incidence of PFJ osteoarthritis (OA) in patients who have undergone ACLR. The first study found that PFJ OA (on X-Ray) was present in 34 of 70 patients (47%) within 5-10 years following ACLR.7 What is even more concerning, another study found that PFJ OA (on MRI) was found in 19 of the 111 patients (17%) at 1-year follow-up, with men 6x more likely to have PFJ OA compared to women. These MRI findings were absent in uninjured controls.8

Key message: Neglect the PFJ at your patients peril!!

That is all for now! I hope you get something out of this summary of information. As always, please feel free to comment if you think that I have missed something, and as always, please share this post with people that you think would like to read it.

Have a great week!


  1. Morgan MD, Salmon LJ, Waller A, Roe JP, Pinczewski LA. Fifteen-Year Survival of Endoscopic Anterior Cruciate Ligament Reconstruction in Patients Aged 18 Years and Younger. The American journal of sports medicine. 2016 Feb;44(2):384-92. PubMed PMID: 26759030. Epub 2016/01/14. eng.
  2. Wright RW, Gill CS, Chen L, Brophy RH, Matava MJ, Smith MV, et al. Outcome of revision anterior cruciate ligament reconstruction: a systematic review. J Bone Joint Surg Am. 2012 Mar 21;94(6):531-6. PubMed PMID: 22438002. Pubmed Central PMCID: PMC3298683. Epub 2012/03/23. eng.
  3. Crawford SN, Waterman BR, Lubowitz JH. Long-term failure of anterior cruciate ligament reconstruction. Arthroscopy. 2013 Sep;29(9):1566-71. PubMed PMID: 23820260. Epub 2013/07/04. eng.
  4. Ardern 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 aspects of physical functioning and contextual factors. British journal of sports medicine. 2014 Nov;48(21):1543-52. PubMed PMID: 25157180. Epub 2014/08/27. eng.
  5. Ardern CL, Taylor NF, Feller JA, Webster KE. Return-to-sport outcomes at 2 to 7 years after anterior cruciate ligament reconstruction surgery. The American journal of sports medicine. 2012 Jan;40(1):41-8. PubMed PMID: 21946441. Epub 2011/09/29. eng.
  6. Barber-Westin SD, Noyes FR. Factors used to determine return to unrestricted sports activities after anterior cruciate ligament reconstruction. Arthroscopy. 2011 Dec;27(12):1697-705. PubMed PMID: 22137326. Epub 2011/12/06. eng.
  7. Culvenor AG, Lai CC, Gabbe BJ, Makdissi M, Collins NJ, Vicenzino B, et al. Patellofemoral osteoarthritis is prevalent and associated with worse symptoms and function after hamstring tendon autograft ACL reconstruction. British journal of sports medicine. 2014 Mar;48(6):435-9. PubMed PMID: 24285782. Epub 2013/11/29. eng.
  8. Culvenor AG, Collins NJ, Guermazi A, Cook JL, Vicenzino B, Khan KM, et al. Early knee osteoarthritis is evident one year following anterior cruciate ligament reconstruction: a magnetic resonance imaging evaluation. Arthritis & rheumatology (Hoboken, NJ). 2015 Apr;67(4):946-55. PubMed PMID: 25692959. Epub 2015/02/19. eng.

Opinions expressed by physiogramworld contributors are their own.

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2 thoughts on “Anterior Cruciate Ligament (ACL) injuries: A general overview

  1. Alyssa says:

    Nice article! What objective measures, particularly functional measures, would you suggest for a young competitive athlete for RTS?

  2. Kitara says:

    I have provided a link to a paper that provides a very clear criterion-based progression from ACLR through to RTS, and I feel that we should all be using this model (or one very similar to it) with all of our ACLR patients/athletes.

    I really like this article, especially going through 6 knee surgeries myself to keep playing Division I college basketball. I was wondering where the link was you are referring to in the statement above.


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