Two Patients: Poor Outcomes after ACL Reconstruction
- Jeff Morton
- 7 days ago
- 11 min read
Do you ever review people who aren't doing great following ACL reconstruction? What are the things that you look out for, and what do you base your plan on?
In this blog I will present two people who presented with pain, stiffness and general dissatisfaction following their ACL operations, one who underwent hamstrings autograft and one who underwent bone-patella tendon-bone autograft. Both individuals have provided consent for me to use their clinical stories for teaching purposes however I will alter their stories slightly in order to further anonymise them.
At the time of meeting these people for the first time, both were in a similar timeframe (between 12-18 months post-op). Both had surprisingly similar clinical presentations; stiffness into flexion >110°, lacking at least 10° extension, deep pain within the knee that was hard to describe and significant atrophy of both the thigh and calf. Interestingly enough, both had undergone their operations abroad (outside the UK) and due to a number of reasons were unable to continue their rehabilitation post-operatively in a smooth manner due to changing locations.
On paper, it would be hard to pick these two apart. However, treating them both the same is destined to have different outcomes. The game here is to troubleshoot what is causing the issue in the first place, to provide high levels of care, send them in the right direction and save them from any more lost time.
Patient A - Let's call him Craig
Always a keen footballer and injury free up until his non-contact ACL tear, Craig was nearing the end of his tether regarding his knee. He felt like a shadow of his former self; previously incredibly social and athletic, his knee now dictated most of what he was able to do. Get around day to day? Sure, so long as it wasn't for hours on end. Work in a shop? Yeah, but with regular breaks and reduced duties. Football? Nope. Not even close.
What made things a little worse, he blamed himself for a lot of the problems he was having with his knee. He wasn't too co-operative with the rehabilitation at the start of the journey, the pain had taken him a little by surprise in the first couple of weeks and then with moving his whole life over to the UK the rehab programme fell off a cliff. When I first met him, he had waited months for his first appointment following his GP referral. He was grateful, but the wait had only added to his frustrations at this point.
I fully understood why he was so frustrated. When I came to assess the leg it was significantly atrophied and was incredibly stubborn when it came to movement beyond 10° extension and 100° flexion. He had undergone a BPTB autograft, and his scars were consistent with this. It didn't appear like there was a significant intra-articular effusion however it's hard to sweep test a knee that won't go fully straight!
In these situations, it can be easy to rush into providing advice and feeling the pressure to deliver the right rehabilitation intervention to restore RoM first and foremost, followed by regaining cross-sectional area of all musculature and peak force capabilities. However I would urge everyone to consider that fact that although you might be a physio (or other MSK rehabber), that doesn't mean everyone you meet has physiotherapy at the top of their needs list. We should always try and understand the problem a little better before jumping in, and have clarity that rehabilitation is what is going to be most beneficial for this person.
First things first. What did Craig actually have done to his knee? Obviously, an ACL reconstruction by his account and supported by the scars on his leg, but unfortunately we aren't seeing many simple isolated ACL ruptures these days. Did he also have any meniscal pathology that was operated on? A significant meniscal tear and subsequent repair attempt could have failed and be causing a mechanical block if it's become displaced again. So I ask him if he recalls any other problems such as cartilage or meniscus surgery at the time? Luckily, Craig is quite clear, it was just the ACL reconstruction.
My index of suspicion that there is a displaced meniscal tear or chondral flap lowers. Maybe he has a cyclops lesion, an area of arthrofibrosis at the footprint of his new ACL. Although this commonly presents mainly with a loss of extension (it can get caught in the intercondylar notch limiting full extension being allowed within the knee), it is a bit unusual for it to cause such significant problems with knee flexion... unless it's massive!
But there still could be something causing this lack of movement that is structural, and ruling out a structural cause is #1 on our list of things to do when presented with a patient suffering these problems.
This brought me back to the clinical exam and something that stood out as a little peculiar to me, one of the scars.
Stab wounds are made for a couple of reasons, but the most common one would be to assist with what we call 'suspensory fixation' this is where the graft is tensioned and held in place by something like an Endobutton. An Endobutton is just one type of fixation and it is a button that is fed through the femoral tunnel before being flipped and placed on the outer cortex of the bone. The button is wider than the tunnel and therefore holds the graft in place and the stab wound allows the surgeon to directly interact with it.
With all of the surgical techniques out there, I wasn't 100% sure if the presence of this scar was reflective of suspensory fixation but that wasn't really the interesting feature... it was the placement. It seemed just a bit too far anterior compared to what I usually see in people following ACL-R who have this type of fixation (that's pretty much all I see where I work!).
As physios, we aren't routinely taught to look out for scar placement but it is something I would encourage everyone reading this to do. Our surgical colleagues are very good at what they do on the whole, so learning what 'normal' looks like can help your clinical reasoning in situations like this, where something felt a bit off, as well as helping you piece together what actually happened in surgery.
This particular piece of information tipped my index of suspiscion of an intra-articular cause into the 'high' category; definitely enough to justify initiating investigations. In particular, I was interested in the position of the tunnels that were drilled in order to place the new ACL graft. Surgical techniques have evolved to the point where the importance of anatomical reconstruction (put the ACL graft in where the native one used to be) is appreciated and will give better outcomes on a more consistent basis compared to non-anatomical reconstructions. However, surgery can be tricky (a huge understatement), and getting the tunnels in the correct position can be part of this, especially as the native ACL femoral attachment sits right at the very back of the medial surface of the lateral femoral condyle.
If the tunnels aren't in the correct position (usually too far anterior), it can lead to graft impingement in the intercondylar notch / shelf leading to a loss of extension. With regards to flexion, anteriorly placed tunnels can cause impingement onto the PCL as the intercondylar notch becomes too crowded, or instead of maintaining consistent tension throughout movement the ACL graft can be slack in extension but remarkably tight in flexion, restricting the knee from bending into deep ranges (a concept called graft isometry).
So seeing this scar that seemed a bit too anterior for my liking seemed clinically relevant, and given that tunnels are drilled into bone, an X-Ray is always the first port of call to evaluate this. In particular, this needs to be a weight bearing X-Ray that has a 'PA' tunnel view (taken from the back, posterior-anterior) and a lateral view. AP views will always be included in the series but it is the tunnel view that might need an additional line in the request to make sure it is completed, for those of you out there who need to know that!
From left to right, we have the tunnel view (PA), lateral view and AP view. It seems that he did have suspensory fixation of his graft through the femoral tunnel, and screw fixation of the tibia.
What is 'normal' I hear you ask? Below are some photos that might prove useful for you to look at as a reference from Pinczewski et al (2008)
What are your thoughts on the positioning of Craig's tunnels here?
To me, there are two main findings; the position of the tunnels in the Sagittal plane and the orientation of the tibial screw indicating the inclination of the graft.
As suspected from the clinical history, clinical examination and subsequent reasoning - Craig's tunnels could well be the source of his issues, and his life circumstances whilst likely unhelpful may carry a little less weighting in the causality of his current situation.
In the above-left picture, the red star is where the femoral tunnel is situated and the blue is closer to the 'ideal' position.
If there is significant graft impingement in the intercondylar roof causing lack of extension, impingement onto the PCL in the notch or isometry issues. It might be the case that no amount of rehabilitation is going to improve the situation. And given the impact that this has had on Craigs life, referring for an orthopaedic opinion in the first instance is the correct choice. He went on to have a CT scan which also showed significant widening of the femoral tunnel and an MRI demonstrated a build up of arthrofibrosis also. He was able to undergo a single stage revision ACL reconstruction and thankfully did a lot better the second time around; it was a lot to go through.
Patient B - Let's call her Zoe
Zoe shared a lot of frustrations that Craig had, she had initially ruptured her ACL 2 years ago and was now around a year following her reconstruction with hamstring autograft. Basketball was her sport and she was extremely keen to be able to return to this, but appreciated it may still be a while off.
Zoe was approximately 10° off of full extension and had flexion to 120°, a full 20 degrees off of her contralateral knee. She had significant thigh wasting of >5cm compared to the other side indicative of quads, hamstring and adductor atrophy. It felt sore on prolonged weight bearing and when trying to exercise and her symptoms seemed deep and a little lateral, towards the joint line. She had no lateral extra-articular tenodesis (LET) but had undergone a lateral meniscal repair with an all inside stitch (important to note as this reduced the chances of irritation on other structures).
As with Craig, the first step is acknowledging that this isn't a 'typical' position to be in so far down the line from her surgery. With no access to the surgical notes, I was a little in the dark as to the state of the meniscus, articular cartilage and what other procedures may have been offered. However Zoe seemed to be quite coherent and her surgical scars didn't throw up any surprises unlike Craig.
Zoe had been doing some exercise for her knee whilst she had been managing solo following her move after University, but unfortunately it was not directed in a way that would address her deficits at this stage. Hearing this, it would be a reasonable starting point to get her started in the right direction to see if we can make any clinical progress.
The problem with this approach, in my view, is that it lacks any insight into the current state of the knee. These days, X-Rays and MRI's are easily accessible and a knee X-Ray has fairly negligble radiation in the long term, so in Zoe's case where she is struggling quite a lot, I find it hard to justify not investigating for an intra-articular cause.
Hopefully, following on from Craig's case you will see the value provided by a humble X-Ray to assess for tunnel position, and although unlikely, significant bony joint pathology.
Please see below lateral and tunnel view images and come up with your own assessment before you read on any further!
...
Not much to see there, right? For Zoe this is great news! There is no strong evidence on this investigation that anything drastic, like starting over from the beginning will need to be undertaken. That's hugely reassuring for someone who has been unable to fulfill their usual life activities for the past couple of years!
For us, it's reassuring but doesn't necessarily rule out an intra-articular cause. There could still be arthrofibrosis or a failed meniscus repair. We don't know the location or type of tear in the lateral meniscus so it could feasibly have displaced again!
This means moving on to an MRI, which in the interests of time I will assure you demonstrated no significant intra-articular pathology. This was a great, but confusing bit of information for me at the time. I was sure there was going to be something on the MRI to explain why she was as stiff and sore as she was.
My confusion aside, the immediate answer was clear. No surgical target to pursue. For Zoe to present as she did without an obvious structural cause was extreme, but not unheard of. On hearing the news, Zoe was pleased but also a little daunted at the road ahead; it wasn't going to be an easy ride for her.
Sure enough it wasn't easy, but without a doubt, being young was on her side. With no structural block to movement, the rehabilitation plan was clear. A relentless focus on restoring full extension first, because without it everything else doesn't really matter.
Active movement into the joint as often as possible, on the exercise bike daily with reassurance that discomfort would ease with consistency. And getting those muscles back! A 5cm thigh circumference difference and limb symmetry indices of 55% on quads and 60% on hamstrings need specific attention. Nothing complicated, just appropriate volume done consistently over months. Knee flexion followed the extension and strength gains as it usually does. Eight months later Zoe had a near straight knee, quads LSI above 80%, and was back playing basketball.
The Clinical Takeaway
If you were to read a handover of both Craig and Zoe, you would get a fairly similar picture, but as I mentioned at the start, you would get very different outcomes if you were to just put on your physio hat and start bashing away at rehab.
For Craig that would have likely ended in a significant flare of symptoms followed by a loss of trust in our profession and potentially never coming back to see us again. For Zoe, sure, the treatment would be what she needed in the end... but that only comes with a significant time investment from Zoe herself. A cost I'm unsure she would have paid if she wasn't assured by clear clinical reasoning and imaging results.
Hopefully you can see that the clinical reasoning that separated the management of these two patients is not complicated. However, it does require a specific kind of knowledge and understanding of what was done in surgery, what the scars tell you, what the imaging shows and what it means.
Crucially, it requires knowing when the problem sitting in front of you has a ceiling that no amount of rehabilitation is going to break through. In the current climate of superficial MSK teaching and lack of postgraduate guidance, unfortunately all of these points only come from deliberate exposure, curiosity, and working in environments where that knowledge is expected of you.
Thank you for reading
Jeff
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