The ACL Conundrum

13.Oct.15 | Legacy

By Steven Whytcross

One of the issues I have with the sports medicine community is our habit of following trends, especially in the case of jumping on the back of the latest research article to justify our “evidenced based practice”.

Over the last few years some fascinating and potentially game changing research has emerged regarding ACL injuries. The evidence shows that

  • Not all ACL injuries require surgery to return to sport
  • ACL reconstruction does not reduce osteoarthritis in the knee
  • Almost half of the people who have an ACL reconstruction stop participating in their competitive sport after surgery

All of this information should add to our conversations with those unlucky patients with ACL injuries. This increased knowledge of outcomes may effect a patient’s decision, short or long-term, in regard to the wont for surgery. But the thing is, ultimately research is still just that… research.

In order to integrate the research findings into practice, we must do more than just read the abstract and recommendations of a study. We must consider the limitations of study design, the population and any resulting bias. We then must consider our own clinical experience and determine how this fits with our every-day practice. It’s easy to jump on a bandwagon, but if we want to truly help our clients we need a considered and informed approach in our management.

Frobell et al (2010) published a large randomised controlled trial of ACL outcomes in surgically and conservatively managed patients and the group recently released a 5-year follow-up (2014). The initial study found that differences in patient satisfaction (on functional outcome scores) and return to sport rates at 2-year follow-up were not significant between groups. Their recommendation was that conservative management should be considered as a primary treatment option in managing an ACL injury.

But if we look closer, 51% of patients in the conservative rehab group ended up having a delayed ACL reconstruction. At this stage, picking the patient who will be happy with their knee without surgery is no better than a toss of the coin. Personally, I need better odds than that to recommend conservative management to a patient who is highly active. Let’s not forget that if we get it wrong – a delayed reconstruction costs more time and money and an even longer return to sport. Interestingly, in the study by Frobell, the patient satisfaction score at 2-years was the same between the two treatment groups, but at 1 year the patients who underwent early surgery had better scores. As we practice within the biopsychosocial model, maybe we need to consider the “psych” element of the extra year required to be happy with a conservatively managed knee.

Our inability to pick the patient who will be able to “cope” with an ACL deficient knee was highlighted in the study by Hurd in 2008. A cohort of 832 patients ended up, after an extensive screening, prehab and rehab protocol, with only 25 patients returning to sport without surgery. While this study also has some downfalls (it was run out of a surgeons office so possibly some population bias, the tolerance for ongoing symptoms and additional pathology was very low, and the prehab protocol was possibly a bit too short), it does reinforce the fact that we aren’t very good at picking the patient who will be able to return to sport without surgery.

Avoiding or delaying the onset of OA has long been a motivation for both patients and therapists when considering ACL surgery. The Frobell study (2014) shows ACL surgery does not prevent arthritis and (although not statistically) significant may actually lead to progression of the disease. This information should definitely be conveyed to our clients especially the one’s who are looking for a fast return to sport.

A study by Eckstein et al (2015) has shown that cartilage homeostasis in the knee is effected following ACL injury, particularly in the first two years.  Articular cartilage is fundamental to our joint health and function; surely we need to consider the cartilage changes that occur post-injury. We commonly accept that progressive loading will result in improved tissue capacity in muscle, tendon and bone.  The same rule exists for all mechanosensitive tissues including cartilage. The OA changes seen in both groups is likely evidence of aberrant loading due to kinematic changes that occur, resultant of a change in normal anatomy, that can’t be normalized with surgery. Alternatively, the advancement seen in knee OA following ACL injury may be due to patients returning to sport before the ‘whole’ knee has had a chance to recover sufficiently; technically the surgery isn’t to blame it’s the rehab.

Finally, there is the body of work by Ardern et al (2011 & 2014) looking at return to sport rates following ACL surgery. The systematic review finds that only 55% of patients return to competitive sport and further, only 65% to their previous level.  If we stop there we can conclude that return to sport following ACL reconstruction is poor and in light of the Frobell study start to question whether surgery is worthwhile. This Ardern paper also highlights that professional athletes are twice as likely to overcome an ACL reconstruction and return to their previous level, bringing the need for surgery in a sub-elite population further into question.

When reading the review more closely, the authors clearly recognise that the rates of return to sport and level of participation are due to a multitude of variables. While sex, age, social factors are non-modifiable factors for the therapist, there are modifiable factors that are placed squarely on our shoulders that influence a patients likely return to sport. The major modifiable factor identified is fact that restoring physical capacity of the patient is the key to patients achieving their return to sport goals. Another significant factor to consider is psychological, regarding the development of kinesiophobia during the post-operative phase. Ultimately, and this should be of no surprise, a patient’s rehab will largely determine whether or not they reach their sporting goals; it is our responsibility to help them get there with a structured, goal-oriented program that encompasses both a physical and psychological recovery.

In my opinion, the research presented throughout this blog gives heart to the patient who can’t undergo surgery; that there is a strong chance of them returning to sport. That said, until we are able to pick the athlete that can or cannot cope with an ACL deficient knee, surgical reconstruction will remain my preference for the active patient with hopes of returning to sport.

We as sports injury practitioners need to be better at educating our patients and managing their expectations, not only regarding their current injury, but also the long-term health of their knee. We need to ensure that when they return to sport their rehab has been exceptional and they are prepared for the demands of their chosen activity. If we can’t achieve this, we are doing our patients a disservice increasing their risk of early OA and failing to achieve their sporting goals.


Steve Whytcross is a director of Physiosports Brighton and a Specialist Sports Physiotherapist (as awarded by the Australian College of Physiotherapy). He has practiced in both Melbourne and London over the last 16 years in multidisciplinary private practices with both elite and recreational athletes.

You can follow Steve on twitter @stevewhytcross