ACL Bracing Protocols or Surgery Following ACL Rupture? What You Need to Know About the Cross Bracing Protocol and BLEX

An anterior cruciate ligament (ACL) injury is one of the most common and frustrating knee injuries, especially for active people. Traditionally, the main pathway after an ACL tear has been surgery (ACL reconstruction) followed by structured rehabilitation. But in recent years, new non-surgical treatment options have been getting more attention — especially ACL bracing protocols that aim to help the ACL heal itself.

Two of the most talked-about ACL bracing protocol approaches are the Cross Bracing Protocol (CBP) and the BLEX protocol. In this article, we’ll explain what these are, how they work, what the research says so far, and what you should consider if you’re weighing up your options.

Why is an ACL bracing protocol even an option for ACL injuries?

For decades, ACL tears were thought to have little to no healing potential. The standard recommendation was surgical reconstruction, especially for younger and active people. However, more recent studies have shown that in certain conditions, the ACL can heal — especially when the torn ends are brought close together and kept stable.

That’s where bracing comes in. The goal of these new ACL bracing protocols is to hold the knee in a position where the torn ends of the ACL are in contact, giving the ligament the best possible chance to heal naturally. This doesn’t work for everyone, but it may be a promising alternative for people who want to avoid surgery or are willing to try a different pathway.

The Cross Bracing Protocol (CBP)

The Cross Bracing Protocol was developed in Australia by Dr Mervyn Cross, and Dr Tom Cross, and has gained international interest. There are a few different versions of this ACL bracing protocol; a 6-week, 8-week, and the most commonly done 12-week protocol. We will be discussing the 12 week CBP here. However, for the 6 and 8 week protocols, you can read about them in the Cross Bracing Protocol information booklet, found here.

How it works

• The knee is braced at 90 degrees of flexion (a right angle – the same angle your knee is usually at when you’re sitting in a chair) immediately after injury.
• This position is thought to bring the torn ends of the ACL closer together, giving them a chance to heal.
• Over a period of weeks, the brace is gradually adjusted to allow more movement of the knee.

The process usually involves:

1. First 4 weeks – Knee is held at 90°. This can be uncomfortable, but it’s considered the most important stage for healing.
2. Weeks 4–12 – Gradual increase in range of motion is allowed by the brace, as well as a gradual increase in strengthening exercises while the brace is on.
3. After 12 weeks – Brace use is reduced, and progressive rehab exercises are emphasised.

What the research says

• Research into this ACL bracing protocol is still early, however, some research has found that about 90% of patients following CBP showed signs of ACL healing on MRI at 3 months.
• Many patients also reported good function and were able to return to sport without surgery.
• However, CBP is still relatively new, and larger long-term studies are needed to compare it directly with ACL reconstruction.

Pros

• Avoids surgery and its risks (e.g., infection, graft failure, re-injury).
• May allow the ACL to heal in its natural position.
• Early studies show promising healing rates.

Cons

• Requires strict adherence to the protocol — which means wearing a brace 24/7 at 90° flexion for a full month. This can be very restrictive for work, driving, and daily life.
• Not suitable for every type of ACL tear (e.g., complete ruptures right in the middle of the ACL may not respond as well i.e., this ACL bracing protocol tends to work better on tears closer to the attachment points of the ACL).
• Research is still early — we don’t yet know long-term outcomes compared to ACL reconstruction.

The BLEX Protocol

The BLEX protocol is another structured ACL bracing protocol, but with slightly different methods and goals. The BLEX protocol is an even newer protocol than the Cross Bracing Protocol.

How it works

• Instead of keeping the knee locked at 90°, BLEX bracing generally allows controlled movement at earlier stages.
• The aim is to balance healing conditions for the ACL with functional mobility and muscle activation.
• Patients typically progress through different stages of brace settings over several weeks, with a focus on early quadriceps activation and gradual return of knee motion.

What the research says

• Evidence for the BLEX protocol is not as strong or widely published as CBP yet.
• Some small studies and clinical reports suggest that structured bracing with early activation may help support healing while reducing stiffness and muscle wasting.
• More data is needed to determine exactly how effective it is compared to both CBP and traditional rehab pathways.

Pros

• May be easier for patients to tolerate because it allows some movement earlier.
• Focus on maintaining quadriceps function, which is critical after ACL injury.
• Could still support natural healing.

Cons

• Evidence is limited and not as well-established as CBP.
• May not hold the ACL ends in as close contact as the 90° CBP position.
• Still requires careful adherence to a strict protocol.

Comparing The ACL Bracing Protocols – CBP and BLEX

What about surgery?

ACL reconstruction is still the most common pathway worldwide. For many people — especially athletes in pivoting sports (like soccer, AFL, rugby league, netball, or basketball) — reconstruction may still provide the most reliable return to sport.

However, ACL bracing protocols like CBP and BLEX provide a potential non-surgical alternative for some patients. Importantly, if healing doesn’t occur as hoped, surgery can still be considered later.

Research also shows us that a 3 month strengthening program leads to the best outcomes for someone post-ACL surgery. That’s quicker recovery, and reduced risk of re-injury. That makes ACL bracing protocols like the ones that we have discussed today an excellent choice, as they are generally 3 months long and incorporate strengthening and range of motion exercises. That means that you don’t actually lose any time compared to if you were going to get an ACL reconstruction 3 months after the injury anyway.

Key considerations if you’re thinking about bracing

Timing matters – CBP in particular is designed for people who start the protocol very soon (preferably within the first week) after injury.

Type of tear – Certain tears (proximal tears, partial ruptures) may respond better than complete midsubstance tears.

Commitment – You’ll need to stick closely to the protocol for it to have the best chance of working.

Supervision – These protocols should only be followed under the guidance of a physiotherapist or orthopaedic specialist.

Expectations – Not everyone will get a fully healed ACL, and some people may still need surgery later.

How Physiotherapy Fits in

Whether you go through an ACL bracing protocol like the CBP, or BLEX, or even if you go down the surgical path, rehabilitation is essential. Physiotherapists play a key role in:

• Monitoring your progress.
• Helping you regain motion safely.
• Strengthening your quadriceps, hamstrings, and hip muscles.
• Guiding you through return-to-sport testing.

Without structured rehab, even the best bracing or surgical procedure won’t give you the function you need.

Final Thoughts

ACL Bracing protocols like the Cross Bracing Protocol and BLEX represent exciting new possibilities in ACL management. For years, surgery was the only serious option, but now we’re seeing evidence that under the right circumstances, the ACL may have the ability to heal itself.

The CBP has shown particularly promising results in early research, while BLEX aims to provide a slightly more flexible, patient-friendly approach. Both options are still emerging, and research is ongoing — so they aren’t a guaranteed replacement for surgery just yet.

If you’ve just injured your ACL and are wondering whether bracing might be an option for you, the best step is to talk with your physiotherapist or specialist as early as possible.

There You Have It

You have now come to the end of your comprehensive guide on what ACL bracing protocols are, and whether you should think about doing them, or just going for surgery. Your physio is going to be extremely important in your journey. While it may feel as though you have a long way to go, don’t worry, it will go quicker than you think. Good luck out there and stay healthy.

Book Here to get started on your journey today, or get in contact by email: [email protected], or phone: 0489 265 145. We look forward to hearing from you.