Episode 276 | Two-Stage Revision ACL Reconstruction Part 2: The Surgery, the Research, and the Road Back

What is up team and welcome back to the ACL Athlete Podcast. Today, we are diving into part two of our series on two-stage ACL reconstruction. If you haven’t listened to part one yet, I’d encourage you to go back and start there. We covered what a two-stage is, why it happens, the specific indications that lead a surgeon to recommend it, and we opened with the story of an athlete I’m currently working with who’s navigating this process right now.

Part one is the foundation. This episode builds on it. For those of you who did listen to part one, here’s a quick recap before we go deeper. And for those of you who are like, “Let me get this recap so I don’t need to listen to it,” go listen to it. Put it on 2x, 3x speed—whatever you prefer. I know I talk slow sometimes, and there’s a lot of value in that episode.

So go listen to that. But for the recap here, a two-stage ACL reconstruction is a planned sequential revision strategy. There’s an intentional sequence to it. Stage one is a bone procedure and a clean-out procedure. The surgeon removes the old graft and hardware, cleans out the damaged tunnels, and fills them with a bone graft to restore the structural integrity of the knee.

The athlete leaves stage one with no ACL graft in place. Stage two happens months later, once imaging confirms the bone has healed, and that’s when the actual reconstruction is performed with a new graft in place. The two primary reasons this becomes necessary are tunnel widening beyond roughly 12 to 14 millimeters—give or take—where there simply isn’t enough solid bone to secure a new graft, and tunnel malposition, where the original surgery didn’t properly align things.

There are different surgical techniques, including anatomical and transtibial approaches, but those are two of the most common. Sometimes the new anatomic tunnel would overlap so significantly with the old tunnel that you can’t safely place the graft without filling it in and allowing it to heal first. They would essentially overlap with each other. I use the analogy of drilling one hole into a wall and then trying to drill another hole directly next to it—or at a different angle—but they intersect.

That makes it really hard to run something through, especially when you’re trying to place a screw. That screw helps anchor where the ACL is going to slide through. We don’t want excessive movement, and we want those tunnels as tight as possible to help secure that ACL in place. So that’s where we left off.

Today, we’re going into the surgery itself in more detail, the interstage period between stage one and stage two—which I’d argue is the most underappreciated part of this entire process—and what the research actually says about outcomes for this two-stage process, and what athletes and clinicians need to take away from all of this practically.

So let’s get into it.

So what is actually happening in that first surgery? I want to give you a clearer picture of what stage one involves because understanding it changes how you think about the interstage period that follows. When the surgeon goes into stage one, they’re not just doing a cleanup. They’re doing foundational reconstruction.

We’re talking about rebuilding the foundation. I compare this to fixing a home. Before you fix the house itself, you need to fix the foundation it’s built on. We can’t do a good stage two where we put a new ACL in if we don’t have a good foundation to start with—and that foundation is the bone itself.

That’s where the ACL is going to anchor. So they’re doing foundational reconstructive work on the bony architecture of the knee. The old graft gets removed. The hardware typically gets removed. Then the tunnels get debrided, meaning the surgeon clears out the fibrous tissue lining the walls until they get back to bleeding cancellous bone.

Sorry, that might sound a little graphic, but the bleeding actually isn’t a bad thing. That bleeding surface helps the bone graft integrate. It brings inflammatory and healing cells to the area and helps start the immune process needed to rebuild things.

None of that is something you’ll directly feel. You’ll have post-op soreness and discomfort, sure, but this process is necessary for the bone graft to integrate well. Then the tunnels get filled.

The material used to fill them matters, and your surgeon will make that decision based on tunnel size, your anatomy, their preferences, and their experience. The most commonly used options are autograft bone or allograft bone.

An autograft comes from your own body, often from the iliac crest—that hip bone you can feel if you place your hand there. An allograft comes from a donor. The iliac crest autograft is generally considered the gold standard because it carries living cells that drive incorporation and typically consolidates faster.

You can think about this similarly to ACL grafts. Autograft means your own tissue. Allograft means donor tissue. In general, allografts tend to integrate more slowly because your body processes them differently.

Most iliac crest autograft cases are ready for stage two somewhere in the range of four to six months. The trade-off is donor-site morbidity. There’s a second area of your body that was operated on, and that area can be sore for a while. Some athletes find that more disruptive than they expected.

Allograft bone dowels are common alternatives when surgeons or athletes want to avoid the donor site. These pre-shaped donor bone plugs are packed into the tunnels. Incorporation is reliable, but it typically takes longer. It could be three months, six months, or even nine months, depending on healing.

Some programs add bone marrow aspirate concentrate, often called BMAC, to allografts to try to accelerate healing biology. The evidence is still developing, but the rationale makes sense. I’m seeing more surgeons use it to try to optimize the healing environment.

But here’s the key thing to understand about stage one: before stage two can be scheduled, the surgeon needs imaging confirmation that the bone graft has incorporated. Plain radiographs around three months can provide an early look. A CT scan at four to six months typically gives the definitive picture.

If consolidation isn’t there, stage two gets delayed. The timeline is driven by biology—not the calendar. And if you’ve listened to this podcast long enough, you know biology is always in control.

A 14-year-old is going to heal differently than a 50-year-old. Every person’s healing timeline is different. That’s one of the hardest realities athletes need to accept early in this process.

Sometimes surgeons also address other issues during stage one. If they find a meniscus tear, they may repair it while they’re already in the knee. There can be other variables depending on the injury history and what led to the two-stage revision in the first place.

Now let’s talk about the interstage period, because this is the part no one really prepares you for.

This stretch between stage one and stage two averages around three to six months—sometimes longer. Your healthcare system can influence this too. Socialized systems may move slower. Other systems may move faster depending on availability and insurance logistics.

In my experience, this is the part athletes are least prepared for because they feel stuck in limbo. Your knee has no ACL. You know that. Every time you step off a curb, get out of a car, or walk on uneven ground, your brain remembers that your primary stabilizer is missing.

That awareness lives in the background. It compounds over time. And at the same time, you’re recovering from surgery without the emotional reward of knowing a new graft is already in place.

In a standard ACL reconstruction, once the early hard weeks are over, there’s a mental anchor. The graft is in. You’re building toward something. In the interstage period, you don’t have that anchor.

You’re also restricted. No cutting. No pivoting. No return to sport. And for many of these athletes, they’ve already been restricted for a long time.

Adding another three to six months on top of that builds real emotional weight.

From a rehab standpoint, the first six weeks focus on swelling control, restoring the full range of motion, and getting the quads active. We’re trying to create a quiet knee—a dry, happy knee.

After that, the focus shifts toward maintaining and building. Stationary bike work, pool work, cardiovascular training, and progressive loading all matter here.

And one tool I want to mention is Blood Flow Restriction Training (BFR). It can help athletes maintain muscle using loads far lighter than what’s normally needed to create a training effect. For ACLers in this stage, it can be incredibly valuable.

It’s not a silver bullet. If we can load heavy, we still will. But BFR helps fill a gap during this unique phase.

The goal entering stage two is not to sit still for six months. This is another prehab phase. We want strength, fitness, and capacity built up as much as possible before stage two.

And now let’s talk about the psychological piece. A 2025 study by Tarchala and colleagues published in Sports Traumatology Arthroscopy found that revision ACL patients scored 17 points lower on ACL-RSI compared to primary ACL patients. That’s a meaningful difference.

Another 2025 study by Mickeles and colleagues published in the Orthopedic Sports Medicine found that psychological readiness was the primary barrier to returning to sport after revision ACL reconstruction. Not strength. Not laxity. Not hop testing. The mental piece was the biggest barrier.

If you’re an athlete in this process, mental work is not optional. That means working with a sports psychologist if possible. It means tracking ACL-RSI scores. It means being honest about fear.

And if you’re a clinician, screen psychological readiness regularly. Don’t wait until physical clearance to realize your athlete isn’t mentally ready.

Now let’s talk about stage two. Once imaging confirms tunnel healing, stage two gets scheduled. The surgeon drills new tunnels into healed bone, places the new graft, and secures it. Done correctly, this reconstruction now has a much stronger structural foundation.

Graft choice matters here. The MARS Group found autografts were roughly 2.78 times less likely to re-rupture than allografts at two-year follow-up.

Common autograft choices include bone-patellar tendon-bone, quadriceps tendon, and hamstring tendon grafts. Each has trade-offs. Your surgeon should help guide that decision based on your anatomy, injury history, and prior surgeries.

Another procedure gaining attention is lateral extra-articular tenodesis, or LET. It adds rotational stability to the knee.

A 2025 meta-analysis by Sutton and colleagues found LET improved return-to-sport rates in revision ACL cases. It’s not needed for everyone, but it’s worth discussing.

After stage two, rehab generally follows the same broad progression as primary ACL reconstruction: protect the graft, restore motion, rebuild strength, develop power, progress to running, jumping, cutting, and eventually return to sport.

And remember—it’s criteria-based, not time-based.

That said, most athletes are realistically looking at 9 to 12 months after stage two. Many may need closer to 12 months or longer.

When you add the interstage period, total recovery often lands somewhere between 14 to 24 months.

That’s the honest timeline.

And athletes deserve to know that upfront.

The research on two-stage ACL reconstruction is still growing, but overall, it’s encouraging. Studies show comparable or better graft survival when the procedure is used for the right indications.

That doesn’t mean the process is easy. It’s demanding. The patient experience can be harder. But structurally, it can absolutely be the right call.

For athletes: trust your instincts if something feels off. Get second opinions. Find surgeons who truly understand revision cases.

For clinicians: ask better questions. Advocate for your athletes. And don’t dismiss red flags.

Treat the interstage period like the important training window that it is. Track psychological readiness intentionally.

And most importantly, stay objective.

To bring this full circle, the athlete I shared in part one is now in stage two rehab.

She’s not at the finish line yet. But what’s different now is clarity.

She knows what happened. She knows why the original surgery failed. She knows what was done in stage one. She knows what’s in her knee now.

And most importantly, she trusts her team. That clarity matters.

When a process is this long and demanding, athletes deserve clarity. They deserve answers. They deserve a plan. She’s getting there, and that’s what this is all about.

It’s not about perfect outcomes. It’s about informed athletes who understand their knee, trust their team, and know that the road—however long it is—is actually leading somewhere meaningful.

I just want to share with you guys that if you need any help in this process, we are here to help.

Thanks to all ACLers, clinicians, coaches, and support systems for listening to both parts of this series. If this was useful to you, share it with someone who needs it—an athlete going through this, a clinician working with one, or a parent trying to understand what their kid is facing.

This is the kind of information that changes how people experience this process. Being educated, informed, and empowered creates intention.

So reach out if you need help. We work with athletes in these situations every single day, and there is a path forward.

Please find our details in the show notes.

I’ll see you guys in the next episode. This is your host, Ravi Patel, signing off.