Pain After Knee Surgery: Quadriceps Avoidance (What It Is and How to Correct It)

Knee pain and injury can happen during anything from high-intensity sports to many everyday activities — the knee is, after all, a pretty fundamental part of our movement.    And depending on the severity of the injury that occurs, sometimes the safest solution is to opt for surgery.

While surgical procedures aren’t anyone’s favorite option, there’s some (bittersweet) solace in recognizing that knee surgeries are actually really common — approximately 600,000 total knee replacements are performed each year (and that doesn’t even include other forms of surgical procedures, like ACL reconstruction or meniscectomies).

With knee surgeries being performed so frequently, medical professionals have a surplus of 

In our clinic, for instance, we have advanced technology to collect individualized data and create custom treatment plans, and we also have the means to notice commonalities in biomechanical deficiencies across all our post-op knee clients.

Some of the most common developments we see after surgery are gait deviations. Experiencing pain in the knee can have a powerful effect on one’s confidence to walk normally, thus leading to compensations to avoid potentially exacerbating the pain.

So, we’re here to break down why this happens for so many people, how it affects your movement, and what you can do to avoid (or correct) it in the long-term.

When Can I Walk Again After Knee Surgery?

Before we dig into the details behind gait deviations, let’s start by addressing the first major question most people have right after surgery: “When can I walk again?”

For the most part, a majority of people are capable of ambulation (i.e., walking without any additional assistance) early in their recovery stages. And from a rehabilitation standpoint, an early return to gait practice is encouraged — as long as it’s with the proper muscular strength, full range of motion, and sufficient balance.

The biggest pitfall to walking soon after surgery is that many people tend to ditch their crutches or cane a little too eagerly. It’s often still possible for them to walk around with assistive devices, but not without a certain degree of hobbling and compensation in their gait.

Without proper biomechanics, walking early into rehabilitation can be detrimental to your gait in the long run, particularly in regards to quadriceps avoidance (which we’ll define further in just a second).

As is with most activities, the quality of your movement is paramount over the quantity of it. Though it’s tempting to get right back to walking, it’s imperative to relearn safe biomechanics to ensure that your gait normalizes throughout your recovery.

So, What Is a Quadriceps Avoidance Pattern?

There can be a lot of nuance to the term, but the overarching definition is decidedly straightforward. When someone walks with quadriceps avoidance, their gait pattern has deviated in a way that avoids sufficient activation and workload within the quadriceps muscles.

Quadriceps avoidance frequently occurs as a result of pain avoidance, but plenty of other issues can contribute, too — some people experience excess swelling or limited range of motion in their recovery, and others have weakened quadriceps muscles. (Some individuals may also alter their gait to avoid unpleasant joint sounds, otherwise known as crepitus.)

In most cases, avoiding the quadriceps tends to develop soon after surgery, as this is when your knee is most vulnerable to the aforementioned problems. But, as time progresses, this gait adaptation can become habitual, ultimately resulting in longer term biomechanical deficiencies. Multiple studies have shown gait deviations up to 8-12 months after knee surgeries

But, just because it’s a common issue doesn’t mean it’s inevitable. Let’s take a closer look at what it really means to “avoid your quadriceps” while walking and why it matters for safe recovery…

The Role of the Quadriceps Muscles in Walking

The main purpose of the quadriceps muscle is to support your bodyweight while walking, particularly when the knee is in a flexed (bent) position. This kind of knee flexion occurs during the “loading response” phase of your gait, which is when a majority of your body weight is shifted onto your leading leg:

But even before your quads have to bear your bodyweight, they’re already being utilized to achieve full extension at the knee, too.

This occurs during terminal swing, which is the moment just before your foot makes contact with the ground for your next step. During this swing phase, your quads extend (straighten) the knee joint in preparation for the impact of your foot making contact with the ground, and they will stay active throughout the flexion of your knee (up until about the mid-stance phase of your gait).

The graph here represents the activation levels of the rectus femoris muscle (your frontmost thigh muscle) during a walking gait analysis:

Because the quadriceps play such a key role in sufficient knee extension and flexion, it’s important to ensure they remain active and strong to protect the knee joint from insufficient shock absorption.

How Can I Tell If I Walk with Quadriceps Avoidance?

One of the biggest indicators for quadriceps avoidance is your knee’s range of motion (ROM).

In order for the lower extremity to adequately absorb shock and progress the body forward, the knee has to have a functional range of knee extension and flexion.

Assessing your ROM can be tricky, especially when it comes down to the nitty gritty details, but you can potentially get a feel for it based on how well (or how comfortably) you can bend and straighten your surgical knee.

But of course, working with a guesstimate isn’t the most targeted approach — that’s why our clinic utilizes advanced sensor technology to measure the hard data behind your individual movement.

Ideal Range of Motion for Walking

Here’s the breakdown of ideal biomechanics for your knee:

At initial contact, your knee should be at or near full extension (around 0-5 degrees). This helps create a rigid “hinge” at the knee as your body weight shifts over your heel.

Following initial contact is the loading response phase, which is where your knee should start to bend to help absorb the increased loading from your bodyweight. Ideally, your knee should flex to approximately 20 degrees for sufficient muscle contraction and shock absorption.

Right after loading response, your knee will return back to full extension to assist with triple extension and forward propulsion.

So, in a typical, unimpaired gait, your knee ROM should progress from 0 degrees (initial contact) to 20 degrees (loading response), then back to 0 degrees (mid-stance).

Comparing the Data: Proper vs. Improper Walking Gait

However, with quadriceps avoidance, your knee is significantly more limited in its full ROM, meaning it can’t achieve the same kind of flexion as it ideally should.

For those of you who are more visual learners, here are some data examples of knee flexion between an unimpaired gait versus one with quadriceps avoidance:

As you can see, there’s quite a noticeable disparity between both. The second graph has more of a straight line between each large peak, which represents a lack of knee flexion between the loading response and mid-stance phases. This line represents your gait if your knee appeared to be fully straight through the duration of a gait cycle, similar to how it’s represented in this video example:

In some cases of quadriceps avoidance, the individual may be able to achieve sufficient ROM in the knee, but they may still walk with a locked or extended knee during their gait cycle. This can indicate more of a mental block, where they’re hesitant to intentionally bear their full weight on the leg.

This is an important point to address: quadriceps avoidance is usually a subconscious habit brought on by neuromuscular pathways when there’s any sign of atrophy, weakness, or pain in or around the quadriceps muscles. Your body responds by straightening the knee to provide “bony” stability where the muscular stability is lacking.

How Can I Prevent (or Correct) Quadriceps Avoidance?

The key to prevention is to start it right away — or at least as soon as possible.

At the beginning of rehabilitation, it’s important to immediately address any limitations in your quadriceps activation and strength. This can be measured with EMG muscle analysis or visual/tactile assessments (like during a quad set or straight leg raise).

Be sure that the exercises used to reestablish quadriceps functionality are targeted to the muscle group; all too often, other lower extremity muscles like the gluteus maximus will take over during training, causing the workouts to be moot.

After enough progression, your surgeon can inform you when it’s safe to begin weight-bearing on the surgical leg. At this point, you can start closed-chain lower extremity strength training with exercises like step-downs or lunges. To ensure your exercises are targeted enough to the quadriceps (specifically for the purposes of walking), focus your work on performing eccentric strengthening drills. This can be done with a band around the knee during said step-downs, lunges, and terminal knee extensions.

Of course, to get a more custom approach for your rehabilitation, don’t forget to speak with your local physical therapist to make steady progress. Normalizing your walking gait takes specific biofeedback training with video, angle measurements, and tactile cueing.

Work Those Quadriceps!

As much as gait deviations are common after knee surgery, remember that they aren’t something to neglect or gloss over. Because it’s often such a subconscious reaction to avoiding knee pain, it’s easy to make a habit out of — making it harder to correct in the aftermath.

It’s entirely normal to feel hesitant or nervous about performing certain exercises and regularized walking gait, but remember: your surgeon and physical therapist will be alongside your recovery, ensuring safe measures and proper form all throughout.

Plus, now you have this blog to help guide you, too! You’ve found the perfect resource to start your journey to gait retraining; so go forth, and walk freely.

Originally published 09-12-2016, updated on 09-15-2021

By Dr. Kevin Vandi DPT OCS CSCS

Dr. Vandi is the founder of Competitive EDGE Physical Therapy — with his background in physical therapy, orthopedics, and biomechanics, he is a highly educated, compassionate specialist. Using state-of-the-art motion analysis technology and data-driven methodologies, Kevin has assisted a wide range of clients, from post-surgery patients to youth and professional athletes. When he isn’t busy working or reading research, he spends his time with his wife Chrissy and their five wonderful children, often enjoying the outdoors and staying committed to an active lifestyle.

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