The most recent systematic review and meta-analysis on return to sport after ACL reconstruction demonstrated disappointing results. For the majority of us who don’t care for elite athletes, the return to sport figures are way off what they should be [REF].

This is a problem. Not only because these injuries and reconstructions are on the rise [REF] or because it is our sole job as physiotherapists to rehabilitate patients back to their previous state, but it has currently unknown socioeconomic consequences with regards to long term health conditions and burden on health services e.t.c.

Naturally, the first question we have to ask ourselves is… Why aren’t people returning to sport at much higher rates than what we currently have reported?

Unfortunately, this isn’t easy to answer, and reasons will be significantly varied depending on the individual, but we should look for themes. One of the biggest themes on why people don’t return to sport / exercises is related to psychological factors [REF, REF, REF].

What has consistently poor correlations with return to sport are biomechanical factors… they just don’t seem to matter as much as you would think to the patient (I do have nuance to this and I think that there is potential that 3D biomechanical deficits do relate to psychological readiness in terms of deceleration capacity or inability to express force in complex situations).

Fear of re-injury, or just not feeling right / lacking confidence seem to be common reasons for not returning to sport, so now we need to ask ourselves some further questions.

1. Can we impact on psychological factors such as fear of re-injury or confidence in the knee?

2. If we can, how on earth do we go about that?

Lets nip number 1 in the bud right away, you can ask any patient or physiotherapist, we definitely CAN impact on pscychological factors with patients by even just talking to them, let alone any physical interventions or rehab plans.

Number 2 – how do we do it?

I’ve not had any formal psychological training to make me better in this area, but this still doesn’t mean I can’t be impactful. The first thing I need to be aware of is my limitations; at the very least I should be able to identify people who are really struggling and be able to refer out to a sports psychologist.

But that isn’t overly common in my experience, so what about interventions?

If it’s one thing for certain, it isn’t a purely strengthening approach. Strong quads ≠ fully rehabilitated!

There are a lot of potential answers to this including cognitive training, reaction training, perturbation training, plyometric training, change of direction training e.t.c. But I’m not confident that any of these approaches would independently improve psychological readiness or confidence if studied, for one simple reason… they all completely ignore the environment that the patient is returning to.

Environment is kinda important… it dictates what decisions need to be made, what problems need to be solved with movement and how.

Imagine you are in a basketball game, you have the ball and are dribbling down the middle of the court. It’s winding down with less than a minute left in the 4th quarter and the game is tied. The pressure is on. You see your teammate come to set a pick on your defender on their left/your right indicating you should drive right only the lane to the basket is blocked by the massive centre on the oppositions team and your teammates own defender is pretty switched on and likely to switch. You’re already going at quite some speed and decide you’re going to have to crossover to fake out your opponent and cut to the left to get past.

If you’ve ever been in this situation, or an equivalent in another game, you know that these problems and decisions aren’t consciously thought through. Jesus, that would be exhausting and take quite a long time. No, what is happening here is that your perception is actually ‘embodied’.

Embodied perception essentially theorises that we perceive the environment not in physical dimensions or perceiving objects, but by directly perceiving the environment by what it ‘affords’ us.

Affordances, as they’re known, are invitations to action from the environment. They are not a constant phenomena. Returning to our basketball example, we aren’t directly perceiving the play of the game in terms of the position and size of the opponents or our teammates; we are perceiving how we can act in that given situation / environment. This can be affected by any number of things, maybe we are absolutely gassed and just don’t have the explosiveness to do this… or maybe we have just returned from an ACL reconstruction and despite the strength training and bouncing on the spot, we just don’t inherently feel like we can trust the knee or use it effectively.

Maybe the lack of experience of having to make complex movement decisions in a chaotic environment with our ‘new normal knee’ has come back to bite us on the ass.

So this is my proposal, why don’t we try to get people making these decisions in a complex environment earlier in the rehab process? Theoretically, it isn’t that difficult to do, we just have to make sure we protect the new ACL graft.

In brief, the main ingredient for an ACL rupture is the axial compressive forces within the jont which can contribute to a forceful pivot shift mechanism. The magnitude of this axial compressive force is significantly related to the magnitude of ground reaction force (or even simpler, how hard you hit the floor). If we can keep the forces to a minimum then we have a lot of wiggle room when it comes to tibial internal rotation, knee abduction and anterior tibial translation as although kinematically these make an ACL rupture easier, without the force behind it the ACL will likely be safe. (REF)

There are some caveats obviously, if the graft is BPTB then enough time needs to have passed for bony healing. If its hamstring graft or quads tendon then we need to give it time to stiffen up in the tibial and femoral tunnels and reduce the chances of it loosening. But from 3-4 months it isn’t an unreasonable suggestion!

To reduce the ground reaction forces we can implement a constraints led approach which essentially comes down to imposing rules such as:

• Keeping speed to a fast walk as maximum

• Having the basket lower than 10ft (Not jumping as high to rebound)

• Keep the field of play small (Reduce the space to build up speed)

• Reduce the number of players on the court

• No crossovers

Or you could take this to a football (soccer) setting:

• Reduce size of the field / pitch to keep speed to a limit

• No jogging or running (this would be a foul)

• Smaller goals (Discourages shots from far out which required large forces)

Scaled down games will allow patients to be embedded in increasingly chaotic environments where they can develop their sense of embodied perception. In other words, they can learn to solve the movement problems they are faced with their new knee.

This approach has the benefit of being ecologically valid compared to other approaches of dashing to blazepods or choosing / shouting out colours whilst completing a drill. I’m not saying that these interventions would have no effect at all, but they aren’t ecologically valid and continue to ignore the environment that the patient is returning to!

As far as I am aware, there is no specific research looking at this. And I am not aware of anywhere currently doing this (please get in touch if you are) so please don’t take this as me disregarding all other types of interventions as useless and suggesting this is superior.

It’s more… a gut feeling that this could be a great advancement for us, amongst everything else we are currently doing.

Let’s see where we are in 10 years!

Thanks for reading, and get in touch if you have anything to add.

Thanks,

Jeff