Patellar Tendon Graft Reconstruction of the ACL (2023)

Patellar Tendon Graft Reconstruction of the ACL (1)


The anterior cruciate ligament (ACL) is a major stabilizer of the knee joint. This key knee ligament is commonly torn during sports activities. The standard operation to fix a torn ACL is with a patellar tendon graft. The surgeon takes out the middle section of the patellar tendon below the kneecap (patella). This new graft includes the strip of tendon, along with attached plugs of bone on each end. For this reason, it is sometimes referred to as a bone-patellar-tendon-bone graft. The surgeon removes the torn ACL and puts the new graft into the knee, making sure to line it up just like the original ligament.

Many types of tissue grafts have been tried. The patellar tendon graft has proven to be one of the strongest for ACL reconstruction. Patients who have this operation generally get back to their usual activities and sports. They often do so faster than people who have their ACL reconstructed with other types of tissue grafts.

This guide will help you understand

  • what parts of the knee are treated during surgery
  • how surgeons perform the operation
  • what to expect before and after the procedure

Related Document: A Patient's Guide to Anterior Cruciate Ligament Injuries


What parts of the knee are involved?

Ligaments are tough bands of tissue that connect the ends of bones together. The ACL is located in the center of the knee joint where it runs from the backside of the femur (thighbone) to the front of the tibia (shinbone).

Patellar Tendon Graft Reconstruction of the ACL (2)

The ACL runs through a special notch in the femur called the intercondylar notch and attaches to a special area of the tibia called the tibial spine.

The patellar tendon is a thick and strong band of connective tissue on the front of the knee. It starts at the bottom of the patella and fastens just below the knee to a bony bump on the front of the tibia, called the tibial tubercle. When using the patellar tendon as an ACL graft, surgeons remove a strip from the middle of it. The graft includes the bony attachments from the bottom of the patella and from the tibial tubercle.

Related Document: A Patient's Guide to Knee Anatomy

(Video) What is a Patellar Tendon Autograft Surgery? - ACL Series


What does the surgeon hope to accomplish?

The main goal of ACL surgery is to keep the tibia from moving too far forward under the femur bone and to get the knee functioning normally again.

Many surgeons prefer to use the patellar tendon when reconstructing the ACL. The graft is often chosen because it is one of the strongest ACL grafts. It's easy to get to, holds well in its location, and generally heals fast.

The anatomy of the graft helps to speed healing and to create a solid connection. When the surgeon implants the new graft, the bony plugs on each end of the graft fit inside a tunnel of bone. This means there is bone-to-bone contact. The body treats the contact of these two bony surfaces as it would a broken bone. It responds by healing the two surfaces together. Healing at the bone-to-bone surface fixes the patellar tendon graft in place.


What do I need to know before surgery?

You and your surgeon should make the decision to proceed with surgery together. You need to understand as much about the procedure as possible. If you have concerns or questions, you should talk to your surgeon.

Once you decide on surgery, you need to take several steps. Your surgeon may suggest a complete physical examination by your regular doctor. This exam helps ensure that you are in the best possible condition to undergo the operation.

You may also need to spend time with the physical therapist who will be managing your rehabilitation after surgery. This allows you to get a head start on your recovery. One purpose of this preoperative visit is to record a baseline of information. Your therapist will check your current pain levels, your ability to do your activities, and the movement and strength of each knee.

A second purpose of the preoperative visit is to prepare you for surgery. Your therapist will teach you how to walk safely using crutches or a walker. And you'll begin learning some of the exercises you'll use during your recovery.

On the day of your surgery, you will probably be admitted to the surgery center early in the morning. You shouldn't eat or drink anything after midnight the night before.

(Video) What are the different ACL Grafts? | Which one is best? Patella vs Hamstring

Surgical Procedure

What happens during the operation?

Most surgeons perform this surgery using an arthroscope, a small fiber-optic TV camera that is used to see and operate inside the joint. Only small incisions are needed during arthroscopy for this procedure. The operation doesn't require the surgeon to open the knee joint.

Before surgery you will be placed under either general anesthesia or a type of spinal anesthesia. The surgeon begins the operation by making two small openings into the knee, called portals. These portals are where the arthroscope and surgical tools are placed into the knee. Care is taken to protect the nearby nerves and blood vessels.

A small incision is also made below the patella. Working through this incision, the surgeon takes out the middle section of the patellar tendon, along with the bone attachments on each end. The bone plugs are rounded and smoothed. Holes are drilled in each bone plug to place sutures (strong stitches) that will pull the graft into place.

Next, the surgeon prepares the knee to place the graft. The remnants of the original ligament are removed. The intercondylar notch (mentioned earlier) is enlarged so that nothing will rub on the graft. This part of the surgery is referred to as a notchplasty.

Once this is done, holes are drilled in the tibia and the femur to place the graft. These holes are placed so that the graft will run between the tibia and femur in the same direction as the original ACL.

The graft is then pulled into position using sutures placed through the drill holes. Screws are used to hold the bone plugs in the drill holes.

To keep fluid from building up in your knee, the surgeon may place a tube in your knee joint. The portals and skin incision are then stitched together, completing the surgery.


What problems can happen with this surgery?

As with all major surgical procedures, complications can occur. This document doesn't provide a complete list of the possible complications, but it does highlight some of the most common problems. Some of the most common complications following patellar tendon graft reconstruction of the ACL are

(Video) ACL Reconstruction Graft Options

  • anesthesia complications
  • thrombophlebitis
  • infection
  • problems with the graft
  • problems at the donor site
Anesthesia Complications

Most surgical procedures require that some type of anesthesia be done before surgery. A very small number of patients have problems with anesthesia. These problems can be reactions to the drugs used, problems related to other medical complications, and problems due to the anesthesia. Be sure to discuss the risks and your concerns with your anesthesiologist.

Thrombophlebitis (Blood Clots)

Thrombophlebitis, sometimes called deep venous thrombosis (DVT), can occur after any operation, but is more likely to occur following surgery on the hip, pelvis, or knee. DVT occurs when blood clots form in the large veins of the leg. This may cause the leg to swell and become warm to the touch and painful. If the blood clots in the veins break apart, they can travel to the lung, where they lodge in the capillaries and cut off the blood supply to a portion of the lung. This is called a pulmonary embolism. (Pulmonary means lung, and embolism refers to a fragment of something traveling through the vascular system.) Most surgeons take preventing DVT very seriously. There are many ways to reduce the risk of DVT, but probably the most effective is getting you moving as soon as possible after surgery. Two other commonly used preventative measures include

  • pressure stockings to keep the blood in the legs moving
  • medications that thin the blood and prevent blood clots from forming

Following surgery, it is possible that the surgical incision can become infected. This will require antibiotics and possibly another surgical procedure to drain the infection.

Problems with the Graft

After surgery, the body attempts to develop a network of blood vessels in the new graft. This process, called revascularization, takes about 12 weeks. The graft is weakest during this time, which means it has a greater chance of stretching or rupturing. A stretched or torn graft can occur if you push yourself too hard during this period of recovery. When revascularization is complete, strength in the graft gradually builds. A second surgery may be needed to replace the graft if it is stretched or torn.

Problems at the Donor Site

Problems can occur at the donor site (the area below the patella where the graft was taken from the knee). A major drawback of taking out a piece of the patellar tendon to reconstruct the ACL is that most patients end up having difficulty kneeling down long after surgery. Lingering pain in the front of the knee is also common.

A portion of bone is taken from the bottom of the patella during the graft procedure. This can weaken the patella. In rare cases, heavy use of the quadriceps muscle (on the front of the thigh) can cause the patella to fracture. This often requires a second surgery to repair the broken patella.

Taking tissue from the center of the patellar tendon can also cause problems. The body attempts to heal the area but sometimes produces too much scar tissue. The extra scar tissue that forms around the donor site may prevent normal motion in the knee. The patellar tendon is not as strong as it was before surgery. In rare cases, this has been linked to a tear in the patellar tendon. Also, the patellar tendon may become easily inflamed. And problems in this area can keep the quadriceps from regaining normal control and strength.

After Surgery

What should I expect after surgery?

You may use a continuous passive motion (CPM) machine immediately afterward to help the knee begin moving and to alleviate joint stiffness. The machine straps to the leg and continuously bends and straightens the joint. This continuous motion is thought to reduce stiffness, ease pain, and keep extra scar tissue from forming inside the joint. The CPM is often used with a form of cold treatment that circulates cold water through hoses and pads around your knee.

Most ACL surgeries are now done on an outpatient basis. Many patients go home the same day as the surgery. Some patients stay one to two nights in the hospital if necessary. The tube placed in your knee at the end of the surgery is usually removed after 24 hours.

(Video) Does a patellar tendon graft for ACL surgery cause knee pain?

Your surgeon may also have you wear a protective knee brace for a few weeks after surgery. You'll use crutches for two to four weeks in order to keep your knee safe, but you'll probably be allowed to put a comfortable amount of weight down while you're up and walking.


What will my recovery be like?

Patients usually take part in formal physical therapy after ACL reconstruction. The first few physical therapy treatments are designed to help control the pain and swelling from the surgery. The goal is to help you regain full knee extension as soon as possible.

The physical therapist will choose treatments to get the quadriceps muscles toned and active again. Muscle stimulation and biofeedback, which involve placing electrodes over the quadriceps muscle, may be needed at first to get the muscle going again and to help retrain it.

As the rehabilitation program evolves, more challenging exercises are chosen to safely advance the knee's strength and function. Specialized balance exercises are used to help the muscles respond quickly and without thinking. This part of treatment is called neuromuscular training. If you need to stop suddenly, your muscles must react with just the right amount of speed, control, and direction. After ACL surgery, this ability doesn't come back completely without exercise.

Neuromuscular training includes exercises to improve balance, joint control, muscle strength and power, and agility. Agility makes it possible to change directions quickly, go faster or slower, and improve starting and stopping. These are important skills for walking, running, and jumping, and especially for sports performance.

When you get full knee movement, your knee isn't swelling, and your strength and muscle control are improving, you'll be able to gradually go back to your work and sport activities. Some surgeons prescribe a functional brace for athletes who intend to return quickly to their sports.

Ideally, you'll be able to resume your previous lifestyle activities. However, athletes are usually advised to wait at least six months before returning to their sports. Most patients are encouraged to modify their activity choices.

You will probably be involved in a progressive rehabilitation program for four to six months after surgery to ensure the best result from your ACL reconstruction. In the first six weeks following surgery, expect to see the physical therapist two to three times a week. If your surgery and rehabilitation go as planned, you may only need to do a home program and see your therapist every few weeks over the four to six month period.

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How strong is a patellar tendon ACL graft? ›

The initial graft tensile strength of bone-patellar tendon-bone autograft is 2977 N with a stiffness of 620 N/mm. This is over 1.5 times the strength and 4 times the stiffness of the native ACL. Additionally, graft fixation should be secure enough to allow early rehabilitation with rapid incorporation of the graft.

What is the recovery time for ACL reconstruction with patellar tendon graft? ›

The graft is strong enough to allow sport at around 6 months however other factors come into play such as confidence, fitness and adequate fitness and training. Professional sportsmen often return at 6 months but recreational athletes may take 10 -12 months depending on motivation and time put into rehabilitation.

How do I know if my ACL graft has failed? ›

The signs of ACL graft failure can include swelling, pain within the knee, locking within the knee, a mechanical block (which can be due to a bucket-handle tear of the meniscus), lack of full motion, and difficulty with twisting, turning, and pivoting.

What is the strongest graft for ACL reconstruction? ›

The strongest option is the BTB graft. The graft incorporates more solid into the bone due to the bone plugs on either end of the tendon. However, BTB grafts have been known to have the slowest recovery time when it comes to meeting rehab milestones and returning to sport.

Will my knee be 100% after ACL surgery? ›

ACL Surgery Recovery Time

For some, it can take up to two years to get back to 100%.

When is ACL graft weakest? ›

The graft complex is actually at its weakest at around the 6 week post operative mark. Kinematic research has shown that open chain exercises cause significantly more anterior tibial displacement and hence more strain on the graft than closed chain exercises.

Does patellar tendon grow back after ACL graft? ›

We use the patellar tendon because it has a higher success rate than the other graft options available. It is the strongest type of graft found in the body and is just as strong as a normal ACL. The other benefit is that the tendon will grow back after taking the tissue out to create the new ACL.

How many years does ACL graft last? ›

Rebuilt to last

Not only is the procedure effective, but repaired tendons perform like new. Reconstruction patients even 20 years later revealed excellent performance, with over 85% still active.

Is your knee stronger after ACL reconstruction? ›

Conclusion: An ACL graft after a reconstruction surgery is initially stronger, but over time becomes weaker, and eventually is almost as strong as your original ACL. These changes occur as a result of the body's natural reaction to the new ACL graft.

Can I damage my ACL graft? ›

You are most at risk of tearing your ACL graft when you return to sport following your ACL reconstruction. Returning to sport within 9 months of ACL surgery puts you at a higher chance of tearing your ACL graft.

What percentage of ACL grafts fail? ›

Unfortunately, ACL graft failures are reported in up to 34.2% in athletes, representing a traumatic and career-threatening event. It can be convenient to understand the various risk factors for ACL failure, in order to properly inform the patients about the expected outcomes and to minimize the chance of poor results.

What is the most painful ACL graft? ›

1, 2 Still, the most commonly used autografts for ACL reconstruction are the bone-patellar tendon-bone (BPTB) and hamstring tendons (HT). There is some evidence to suggest that BPTB autografts produce more pain than HT autografts both in the immediate postoperative period as well as in the long term.

What is the gold standard for ACL reconstruction? ›

The patellar tendon graft (PTG) has always been the gold standard for anterior cruciate ligament (ACL) reconstruction.

What is the price of ACL graft? ›

ACL Ligament Reconstruction Surgery Cost in India is between 2.5 lakh to 3.5 lakh.

What is the gold standard for ACL repair? ›

Patellar Tendon

It is the graft with the longest track record and is consider by many to be the “gold-standard” for ACL reconstruction. In most circumstances this is the graft recommended for professional athletes and in any young active individual.

What is the hardest part of ACL recovery? ›

Full immobilization is the worst thing you can do after ACL surgery.o avoid this, make sure to begin rehabilitation right away and begin weight-bearing with your crutches and your brace to promote healing. Anterior Knee Pain: The front of your knee hurts, generally around your kneecap.

How long after ACL surgery can you bend your knee 90 degrees? ›

How Long Does it Take to Fully Bend Your Knee After ACL Surgery? Full knee flexion after ACL surgery is typically achieved gradually over time, with about 90 degrees of knee flexion reached by the end of week one post-op and full knee flexion achieved by week 4-6.

Are you more likely to tear your other ACL after surgery? ›

However, studies have indicated that the chance of re-tearing the ACL following surgery is modest, ranging from 2 to 10 percent. This suggests that for every 100 individuals who undergo ACL reconstruction, 2 to 10 will tear their ACL again.

What is the danger zone for ACL reconstruction? ›

The 'danger zone' is between 3 to 9 months. As the graft develops a new blood supply within the knee after surgical reconstruction, the new cells remodel the graft and it becomes stronger. By 9 months, the graft will look and function like a new ligament and should be strong enough to cope with a full return to sports.

When is the ACL graft the strongest? ›

James Andrews and since has shown similar data2, the initial graft strength of a 10 mm graft right after the surgery is about 120% of that of an intact ACL. A 14mm graft is even stronger. However, at 6-8 weeks post-op the graft strength deteriorates to about 60% of the intact ACL.

What is the average ACL graft size? ›

Indeed, the graft needs to be around 70 mm long, with 20 mm on the femoral and tibial sides and 27 to 42 mm in the joint space. An adjustable Pullup cortical suspension device on each side allows the surgeon to adjust the graft length in the tunnels and to manage graft tension.

What are the advantages of patellar tendon graft? ›

From a biologic standpoint, the advantage of a patellar tendon graft is that the graft bone heals to host bone in six weeks, which is faster than the 8 to 12 weeks it takes for soft tissue healing.

What happens to the patella after ACL surgery? ›

A major drawback of taking out a piece of the patellar tendon to reconstruct the ACL is that some patients end up having difficulty kneeling down. Lingering pain in the front of the knee is also possible. A portion of bone is taken from the bottom of the patella during the graft procedure. This can weaken the patella.

How do you strengthen patellar tendon after ACL surgery? ›

Therapeutic Exercises:

Knee extensions 90°-45°, progress to eccentrics. Advance closed kinetic chain activities (leg press, one-leg mini squats 0-45° of flexion, step-ups begin at 2” progress to 8”, etc.) Progress proprioception activities (slide board, use of ball, racquet with balance activities,etc.)

Will my ACL ever be the same after surgery? ›

Knee function after ACL repair depends on a lot of factors, which can vary — sometimes a lot — from one person to another. After surgery, you can expect to begin physical therapy fairly quickly. Physical therapy helps your knee regain flexibility and strength while also promoting healing of the joint tissues.

What happens 20 years after ACL surgery? ›

36% of the patients had suffered a rupture of either the opposite knee's ACL or tore the graft in the surgical knee. Patients are often still very active. 20 years after surgery, 35% of patients still engaged in very strenuous activities like soccer. 15% engaged in strenuous activities like tennis or skiing.

What happens if you stretch your ACL graft? ›

Anterior cruciate ligament graft stretching can lead to the following conditions: chronic instability. chondral injury. meniscal tears.

When is ACL weakest after reconstruction? ›

This usually starts at approximately weeks 6–8 at which time animal studies have shown that the graft is at its weakest point in the post reconstruction process [16]. Some studies indicate that the graft may only reach failure loads of 11 to 50% at 1 year post-operative [17].

Is a cadaver ACL better than a hamstring? ›

What is this? The results of this research showed that people who had ACL surgery with a hamstring ACL graft from their own body had an 8% failure rate at 10 year follow up. In stark contrast, the group that underwent an ACL reconstruction with a cadaver (Allograft) ACL graft had a failure rate of 26%.

What is the most common ACL graft? ›

The patellar tendon and hamstring autografts are the most common choices for ACL reconstruction. The patellar tendon runs from the knee cap (patella) to the lower leg bone (tibia). Surgeons have the most experience with this autograft and it is the most widely used.

Can you tear your patellar tendon after ACL surgery? ›

Use of the central one third bone–patellar tendon–bone autograft is an accepted technique for anterior cruciate ligament (ACL) reconstruction. Patellar tendon rupture following ACL reconstruction is an acknowledged, although rarely reported, complication of this procedure.

Is it easy to damage ACL graft? ›

Recovery from ACL surgery is a slow process, and the types of activities you do at the start of your recovery rarely put enough stress on the new graft to cause a tear. This means that it will be very hard to reinjure/rupture your ACL graft right after your surgery.

How strong is a tendon graft? ›

Double-looped semitendinosus grafts have a stiffness of 861 to 954 KN/M and can sustain maximum loads of 4304 to 4590 N.


1. Hamstring Autograft Technique for ACL Reconstruction Surgery
(MedStar Health)
2. Patellar Tendon Graft Harvest
(Memorial Hermann)
3. Allograft ACL Reconstruction Surgery performed by Kevin R. Stone, MD
(The Stone Clinic)
4. ACL Reconstruction With a Bone Patellar Bone Graft
5. Knee Arthroscopy: ACL Reconstruction (Bone Patellar Tendon Bone Autograft + Meniscus Repair Surgery)
(Mark Ayzenberg, MD)
6. Advancements in Quadriceps Tendon ACL Reconstruction
(What's New in Orthopedics)


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