Cutting Through the Noise

An Evidence-Based ACL Rehab Q&A from 15 Years of Clinical Practice.

After dedicating the last decade of my 15-year physio career to the ACL, I've seen one thing consistently hold people back more than the injury itself.

Uncertainty.

Bad advice, outdated protocols, and a lack of clear direction can turn a 9-12 month recovery into a years-long struggle.

I've heard the same frustrations in my clinic, in the workshops I've run, and in the online courses I've presented on.

This post is trying to provide an antidote.

In this blog, I've compiled the most common and critical questions from both patients and physios that I’ve received over the years and answered them with everything I've learned from a decade in the trenches, backed by the best current research.

This hopefully answers your questions too.

Let's dive into the questions.

Q: I've just torn my ACL. Do I definitely need surgery?

A: This is often the first and biggest question on everyone's mind. For a long time, the default answer for a young, active person was a resounding "yes," and surgery rates have certainly climbed—one Australian study noted a 74% rise in ACL reconstructions for those under 25 (Zbrojkiewicz et al., 2018).

However, a wealth of high-quality research now tells us that immediate surgery is not the only path to a great outcome.

My philosophy, which is backed by this evidence, is to champion a "rehab-first" approach. Let’s look at why.

• Great outcomes are possible with rehab alone. A landmark study (Frobell et al., 2013) compared early surgery to a group that did rehab first with the option of later surgery. At the five-year follow-up, there were no significant differences in pain, function, or quality of life between the groups. The incredible finding? Nearly half (49%) of the people who started with rehab never ended up needing surgery at all. They became successful "copers" who could function at a high level without an ACL.

• You can train your knee to "cope". This ability to function without an ACL isn't necessarily something you're born with. Ground-breaking research (Thoma et al., 2019) showed that with just 10 targeted exercise sessions, 45% of patients who were initially considered "non-copers" (meaning their knee had pain, stiffness and instability) could change their status to "potential copers."

• Surgery doesn't guarantee a return to sport. It's a common myth that surgery is the only ticket back to the game. The data shows that only about 65% of non-elite athletes return to their pre-injury sport after surgery (Ardern et al., 2014).

• It's safe to wait. A common fear is that waiting for surgery will cause more damage to the cartilage or meniscus. However, research from Filbay (2019) shows there is no high-quality evidence to support this fear, provided a proper rehabilitation program is in place. In fact, waiting allows you to undergo a dedicated "prehab" program, which has been shown to lead to significantly better outcomes if you do end up having surgery later (Failla et al., 2016).

• The initial injury, not the treatment, is the biggest driver of future arthritis. Another valid concern is the long-term risk of osteoarthritis (OA). A major review (Poulsen et al., 2019) concluded that the risk of OA increases 4 to 6-fold after the initial injury, regardless of whether you have surgery or not.

So, the modern, evidence-based approach is to give everyone a trial of high-quality rehabilitation first. This allows many to avoid surgery altogether, and for those who still feel unstable and choose surgery, they go into it stronger, calmer, and better prepared for a successful outcome.

Q: I've decided on surgery. Is there anything I should do before the operation?

A: Absolutely. This is what we call "prehab," and it's one of the most powerful things you can do to improve your outcome. An athlete who goes into surgery with a "quiet" knee consistently has a smoother, faster, and more successful post-operative course.

The initial goals are non-negotiable:

• Calm the knee down: Eliminate as much swelling as possible - ideally no more than a trace of fluid on Sweep Testing. A swollen knee is an inhibited knee.

• Restore full range of motion: You must get your knee fully straight, matching the extension of your other leg. This is critical for getting your quads to recruit better

• Get strong: We aim for your quad and hamstring strength to be at least 90% of your uninjured leg before you go under the knife.

Once the knee is quiet, the real work begins. Ideally, you should complete at least 6 weeks, but preferably 12 weeks, of dedicated strength training before your operation.

This should look very similar to a standard gym program, hitting exercises like knee extensions, leg presses, squats, deadlifts, and calf raises 3-4 times per week, aiming for 3-4 sets of 8-12 reps per exercise. This gets you truly ready for the demands of surgery and the rehab that follows.

Click on the image above and go to Appendix section at the end for a great recipe of pre-op exercises

This prehab window is also the perfect time to get smart with our data.

We capture pre-operative strength and hop test data from the uninjured limb. This is crucial, aligning with the work from Wellsandt et al. (2017) and their Estimated Pre-injury Capacity (EPIC) concept. This research showed that using this pre-op data as the benchmark for the operated leg later on was more sensitive and specific for detecting second ACL injuries in the first 2 years upon returning to sport.

Q: I'm in the first 4-6 weeks after surgery. What should my main priorities be?

A: This is what I call "The Foundation Phase," and it's the most critical period for your long-term success. Think of it like building a house; if you don't get the foundations right, you're building on sand.

Based on my clinical experience and the evidence, including the seminal paper from Dr. Matt Buckthorpe and colleagues, here are the six key areas to focus on in the first 4-6 weeks.

1. Taming Pain and Swelling: This is fundamental. Pain and swelling aren't just annoying; they actively inhibit your muscles (that quad really doesn't like swelling!) and block your movement. You need to learn to monitor it (and if you’re a patient, get your physio to teach you how to monitor it via The Sweep Test or tape measure): if the knee puffs up or gets significantly sorer after an exercise, it's valuable feedback that you've likely pushed a bit too hard.

Practical Tip: We aim for pain to be consistently low (0-2/10) in the knee joint itself. For swelling, you can track your knee circumference with a tape measure around the kneecap. An increase of more than 1cm often suggests you've overdone it.

2. Reclaiming Range of Motion (ROM): Getting your knee bending and straightening is vital. Getting full knee extension (your leg completely straight) back as soon as possible is absolutely critical. Losing even a tiny bit of extension early can cascade into longer-term issues.

Practical Tip: Simple exercises like 'prone hangs' (lying face down on your bed with your leg hanging off the edge) are brilliant for extension. For flexion, gentle heel slides are a staple.

3. Waking Up the Muscles: After surgery, your brain often slams the brakes on your quad muscle, a phenomenon we call Arthrogenic Muscle Inhibition (AMI) or "quad shutdown". You cannot properly strengthen a muscle that your brain is actively inhibiting. Part of early rehab is overcoming this with smart exercise selection and specific tools if needed.

Practical Tip: A great early test is checking for 'quad lag'. Can you lie on your back and lift your straight leg off the bed without your knee bending? If you can do 10 reps smoothly, your quad is starting to fire properly.

4. Mastering Movement Quality: How you walk out of the clinic today genuinely impacts how you'll run in a few months. Compensatory movements like limping become ingrained habits incredibly quickly. Early rehab must include retraining a good quality walking pattern and fundamental movements.

Practical Tip: Before ditching crutches, we need to see minimal pain/swelling, full active knee extension (no lag!), and a reasonably 'normal' walking pattern. Don't rush this step!

5. The Head Game: An ACL injury is as much a mental battle as a physical one. Dealing with the shock, fear, and frustration is a massive part of the journey. Having solid emotional support from your physio, teammates, and family is vital.

6. Preserving Overall Fitness: While your knee needs careful management, don't let your general fitness disappear. Safe cardio options early on include an arm bike or stationary cycling once your knee bend allows. For strength, focus on your upper body and exercises for your uninjured leg.

Q: I hear a lot about tools like Cryotherapy devices, NMES, BFR, and the pool. What's your take?