Yes—knee replacement often removes the ACL and sometimes the PCL, while most major tendons stay intact and are repaired if split.
You’re not overthinking this. The words “tendon” and “ligament” sound like the stuff that makes your knee work, so the idea of cutting them can feel scary.
Here’s the plain truth. A knee replacement does involve cutting through soft tissue to reach the joint, and most total knee replacements remove at least one ligament inside the joint. At the same time, surgeons work to keep the main tendon system that straightens your knee working well.
This article is general information, not medical advice. Your surgeon’s plan can differ based on your anatomy, arthritis pattern, and implant choice.
How Knee Replacement Reaches The Joint
A total knee replacement starts with an incision, then the surgeon opens the layers over the joint. The goal is a clear view of the damaged surfaces so the new parts sit in the right place.
Most approaches move the kneecap aside so the surgeon can work on the thigh and shin bones. This is the part that makes many people think tendons were cut, since the front of the knee is dense with tendon tissue.
- Make The Skin Incision — A front cut lets the surgeon reach the joint.
- Open The Joint Lining — The capsule is opened so the kneecap can move aside.
- Move The Kneecap Safely — The kneecap is shifted while its tendon attachment stays in place.
- Remove Damaged Bone And Cartilage — Worn surfaces are trimmed so the implant matches your alignment.
- Close And Repair Soft Tissue — The capsule and split tendon fibers are stitched closed.
If you hear “quad-sparing” or “muscle-sparing,” it refers to how the surgeon works around the quadriceps tendon and thigh muscle. The deeper joint work stays similar.
Your operative note may say “arthrotomy,” meaning an opening into the joint capsule. That opening is closed with sutures so the capsule heals.
You may also see phrases that describe kneecap handling.
- Read “Medial Parapatellar” — The opening runs along the inner edge of the kneecap area.
- Read “Subvastus” — The surgeon works under the inner thigh muscle to move the kneecap.
- Read “Lateral Release” — Tight tissue on the outer side is loosened to help the kneecap track.
Tendons And Ligaments In Knee Replacement Surgery: What Gets Cut
It helps to separate three categories. The ligaments inside the joint, the ligaments on the sides of the knee, and the tendons that move the knee. They don’t all get treated the same way.
Inside the joint, the anterior cruciate ligament (ACL) is often removed in total knee replacement. The posterior cruciate ligament (PCL) may be kept or removed, depending on the implant style and the condition of the ligament.
On the sides, the medial and lateral collateral ligaments usually stay in place. Surgeons may “release” tight tissue on one side to straighten the leg, yet that is not the same as removing the whole ligament.
In knees with a big bow-leg or knock-knee shape, scarred tissue, or old ligament injuries, balancing can take more work. Surgeons may loosen tight tissue, tighten loose tissue with sutures, or use an implant with added constraint that gives extra side-to-side control. That choice is about stability, not strength.
For tendons, the big picture is reassuring. The patellar tendon and quadriceps tendon keep doing their job after surgery. Some approaches split a small portion of quadriceps tendon fibers to open the knee, then repair them during closure.
- Ligaments Inside The Joint — The ACL is often removed; the PCL depends on the implant plan.
- Ligaments On The Sides — The collateral ligaments are usually preserved and balanced, not taken out.
- Tendons In Front — The extensor tendon system stays intact; any split fibers are repaired.
Ligaments That Are Commonly Removed
When people ask “are tendons and ligaments cut during knee replacement?” they usually mean total knee replacement, not a partial replacement. In a partial knee replacement, more of your natural joint structures can stay, since the surgeon replaces only one compartment.
In most total knee replacements, surgeons remove the ACL to make room for the implant and to let the new joint surfaces track properly. AAOS describes this pattern when explaining implant designs and why the ACL is often removed.
The PCL is the next one to know. Some implants keep it (often called cruciate-retaining). Other implants remove it and use implant geometry to guide motion (often called posterior-stabilized).
Want a simple gut-check? If your surgeon says your implant will “keep the PCL,” you’ll likely keep that ligament. If they say the implant will “substitute for the PCL,” it is usually removed. For a plain-language outline of knee joint replacement, see MedlinePlus knee joint replacement.
- Expect The ACL To Go — It’s commonly removed in total knee replacement.
- Ask About The PCL — It may be preserved or removed, based on implant style.
- Count On Side Stability — The collateral ligaments are usually kept and balanced.
Tendons And Muscles: What Gets Split And What Stays Whole
Your knee’s “power cable” is the extensor mechanism—quad muscle, quad tendon, kneecap, patellar tendon. That system straightens the knee and controls stairs, chairs, and getting up from the floor.
Most knee replacements do not detach the patellar tendon from the kneecap or from the shin bone. That’s a relief for many people, since a full detachment would change rehab a lot.
Where does tendon cutting show up? Some common approaches make an opening that crosses the upper part of the kneecap area, which can include a split through part of the quadriceps tendon fibers. That split is then stitched during closure, much like any other tendon repair.
Other approaches work under or around the thigh muscle to reduce tendon splitting. The tradeoff can be a tighter working space, and not every knee or body shape is a match for every approach.
- Protect The Patellar Tendon — It usually stays attached and is moved, not cut free.
- Repair Any Split Fibers — If the quadriceps tendon is split, it is sutured closed.
- Balance Soft Tissue Tension — Small releases can help the knee track and straighten.
Implant Choices That Change Ligament Handling
Implant design plays a big role in what happens to the PCL, and it helps explain why two friends can have “knee replacement” yet hear different details.
Some people hear “bicruciate-retaining” and assume it’s standard. It’s one option, and it’s not offered everywhere. If keeping both cruciate ligaments matters to you, ask if your surgeon offers it.
AAOS lays out the main implant categories and explains how some designs keep the PCL while others substitute for it. You can read their breakdown on knee replacement implant designs.
| Implant Style | Cruciate Ligaments Kept | How Motion Is Guided |
|---|---|---|
| Cruciate-Retaining | PCL kept, ACL usually removed | Your PCL helps control back-and-forth motion |
| Posterior-Stabilized | ACL and PCL removed | Implant parts guide motion in place of the PCL |
| Bicruciate-Retaining | ACL and PCL kept | Implant is built to mimic ligament control |
Even within the same implant family, surgeons may make small soft-tissue releases so the knee straightens and bends without wobbling. That step is often called soft-tissue balancing. It’s less about “cutting ligaments out” and more about adjusting tension so the new joint tracks smoothly.
Healing, Rehab, And What You’ll Feel In The First Weeks
It’s normal to feel soreness in the front of the knee after surgery, even if your main tendons were not detached. The skin incision, joint capsule opening, and tendon-splitting (when done) all need time to heal.
Most people notice two flavors of discomfort. One is surface tenderness around the incision. The other is a deeper ache or tightness that shifts as swelling changes and as you start bending and straightening the knee more.
- Work On Straightening Early — Full extension helps walking and reduces a bent-knee limp.
- Build Bend Gradually — Flexion comes with repetition, swelling control, and patience.
- Use Ice And Elevation — Lower swelling helps pain and helps you move more freely.
- Do The Home Exercises — Short, frequent sessions beat one long grind.
- Protect The Wound — Follow your discharge sheet for showering and dressing care.
Call your surgical office right away if you notice spreading redness, drainage, a fever, chest pain, or sudden calf swelling. Those signs need a same-day check.
If your surgeon did split part of the quadriceps tendon, you may feel extra pulling above the kneecap during early bending. That sensation often eases as the tendon repair and capsule heal and as the thigh muscle wakes back up.
Questions Worth Asking Your Surgeon
You don’t need to memorize anatomy to get a clear plan. A short list of direct questions can tell you what will be kept, what will be removed, and what your rehab will center on.
- Ask Which Ligaments Will Stay — Get a clear answer on the ACL and PCL in your case.
- Ask Which Approach Will Be Used — Learn if the quadriceps tendon is split or worked around.
- Ask How The Kneecap Will Be Managed — Patella tracking and resurfacing plans vary.
- Ask What Rehab Targets Come First — Know the early goals for straightening and walking.
- Ask What Red Flags Mean A Call — Get a simple list of symptoms that need prompt review.
If you want one line to bring, say, “Please tell me which ligaments you plan to keep, and whether any tendon fibers will be split and repaired.” It’s direct, and it invites a plain-language answer.
Key Takeaways: Are Tendons And Ligaments Cut During Knee Replacement?
➤ ACL removal is common in total knee replacement.
➤ PCL may be kept or removed, based on implant style.
➤ Side ligaments usually stay and are balanced for stability.
➤ Patellar tendon stays attached in most cases.
➤ Ask your surgeon about approach, repairs, and rehab goals.
Frequently Asked Questions
Does A Partial Knee Replacement Cut The ACL?
Often, no. Many partial knee replacements keep both cruciate ligaments, since only one compartment is resurfaced. Still, your surgeon may change the plan if a ligament is torn or the arthritis pattern is wider than expected.
Ask if your ACL is intact on imaging and if the other compartments are healthy.
Will Removing The ACL Make My New Knee Feel Unstable?
Not in the way people picture with a sports ACL tear. The implant’s shape and the preserved side ligaments guide stability during walking. If you feel buckling after surgery, tell your therapist and surgeon so they can check strength, swelling, and alignment.
Swelling and quad weakness can mimic instability early on.
Is The Quadriceps Tendon Always Cut In Total Knee Replacement?
No. Some approaches split part of the quadriceps tendon, then repair it during closure. Other approaches work under the thigh muscle to reach the joint with less tendon splitting. Your body shape, stiffness, and surgeon’s routine affect which route fits.
Subvastus and midvastus routes may spare tendon splitting for some knees.
How Can I Tell Which Implant Type I’m Getting?
Ask your surgeon to name it in plain words, like cruciate-retaining, posterior-stabilized, or another design. You can also check your pre-op paperwork or implant consent form. If you see language about “substituting for the PCL,” that points to posterior-stabilized style.
Ask if it has a post-and-cam, or keeps your PCL.
What If My Side Ligaments Are Damaged Before Surgery?
Tell your surgeon about any old ligament injuries, even if they happened years ago. They may order stress X-rays or plan a more constrained implant that adds stability. Rehab can still go well, yet the brace plan and early walking plan may differ.
Old MCL tears can need a more constrained implant.
Wrapping It Up – Are Tendons And Ligaments Cut During Knee Replacement?
Yes. In most total knee replacements, the ACL is removed, and the PCL may be kept or removed. Major tendons that straighten the knee usually stay attached, though some approaches split a portion of quadriceps tendon fibers and repair them. If you want certainty, ask your surgeon which ligaments will stay and what soft-tissue repairs they plan.
Mo Maruf
I created WellFizz to bridge the gap between vague wellness advice and actionable solutions. My mission is simple: to decode the research and give you practical tools you can actually use.
Beyond the data, I am a passionate traveler. I believe that stepping away from the screen to explore new environments is essential for mental clarity and physical vitality.