Anterior Cruciate Ligament Tears and Their Treatment: arthroscopic and minimally-invasive surgery for ACL reconstruction
Edited By: Christopher J. Wahl, M.D., Suzanne L. Slaney, PA-C, ATC, MMS
Last updated Friday, October 20, 2006
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Figure 3 - Arthroscopic view of a right knee. Several years after a tear, the ACL has almost completely resorbed from the knee.
Figure 4 - Bone-patellar tendon-bone graft. Left, the graft is harvested from the patellar tendon. Middle, the graft has bone 'plugs' at each end. Right, the bone plugs are docked into the femur and tibia. The patellar tendon becomes the ACL (arrow). Diagram courtesy of Smith+Nephew Endoscopy.
Figure 5a - Schematic drawing (top) and intra-operative photograph (bottom) of a prepared quadrupled hamstring autograft.
Figure 5b - Arthroscopic view of a knee after ACL reconstruction of the ACL using a hamstring autograft.
Figure 6 - Schematic diagram of a double-bundle ACL reconstruction. Diagram courtesy of Smith+Nephew Endoscopy.
Considering surgery
Who should consider arthroscopic anterior cruciate ligament (acl) reconstruction for anterior cruciate ligament - acl - tear and in what cases?
The
ultimate decision to surgically reconstruct the ACL depends greatly on the
patient’s post-injury knee stability, ability to carry out activities of daily
living, activities and athletic endeavors, and expectations to return to such
activities.
Arthroscopic ACL reconstruction is considered when:
- The patient is a young
individual or athlete who will be at significant risk for disability
and/or further knee injury if normal knee mechanics are not restored
- The episodes of instability are
a significant problem for the patient, and inhibit his or her ability to
perform the activities of daily living, sporting activities, or
job-specific requirements
- The patient has truly exhausted
non-operative treatments, like physical therapy, and are still having
frequent giving-way episodes, instability, and an inability to perform the
usual activities of daily living or walk without assistive devices such as
crutches or a brace
- There is concomitant injury to
other structures in the knee
- The patient is sufficiently
healthy to undergo the procedure
- The patient understands and
accepts the risks and alternatives to the procedure
- An appropriate and
comprehensive diagnostic evaluation has been performed and the nature of
the problem is clear
- The surgeon is experienced and
familiar with the techniques and treatments for arthroscopic ACL
reconstruction
- The patient is capable and
willing to comply with a comprehensive post-operative physical therapy
program
Even
if a patient believes their knee instability is minimal (they are not having
frequent “buckling” episodes), the knee will still incur “wear and tear”. This will essentially lead to osteoarthritis
by roughening the joint surfaces, adding additional forces to the menisci and
thereby damaging this tissue. Other
stabilizing ligaments in the knee will be stressed as they compensate for
additional forces that the intact ACL would typically act against.
What happens if nothing is done for anterior cruciate ligament - acl - tear (best case/worst case scenarios)?
For individuals who choose to not have surgery,
rehabilitation of the injured knee is frequently recommended. In order to restore as much function as is
possible; a rehabilitative treatment program may help to prevent instability
and “giving way” episodes.
Rehabilitation will focus on strengthening the muscles around the knee
in order to provide better support, control, and stability.
There is
nothing inherently dangerous about a mildly unstable knee so long as the
patient is able to be adequately braced and willing to use appropriate
assistive devices (cane, crutch, or walker) that will prevent falls or further
injuries. This may require significant changes in lifestyle and activities to
reduce the risk of instability events. For instance, an individual may have to
avoid activities such as basketball or soccer and participate in non-impact
activities such as biking or swimming for fitness. The goal is for patients to
find activities where the knee feels stable and is pain free.
A minority of patients will continue to have instability
to the degree that they are unable to walk or put weight on the extremity without
it buckling on them. These persons are
best served by surgery to stabilize the knee and restore function.
With or without surgery, a knee that has an ACL injury is
at risk to develop osteoarthritis in the knee over time. Even a perfectly performed surgery cannot
restore absolutely ideal knee kinematics.
However, the arthritis usually takes years to develop if the mechanics
of the knee are optimized.
What options exist for surgery for anterior cruciate ligament - acl - tear?
Patients should be aware that there are different grafts
available for use when reconstructing the ACL.
Due to the uniqueness of each knee and injury from person to person it
is best to discuss the different possibilities with an appropriately trained
orthopedic surgeon.
What is the
difference between ‘repair’ and ‘reconstruction’?
A surgical ‘repair’ of the ACL alludes to the ability
to leave the injured ligament in place and attempt to ‘fix’ it back to the
tibia or femur from which it has torn.
In rare cases, the ligament will have pulled off of the bone
(occasionally taking a small piece of bone with it). In such cases, the surgeon can suture the
ligament or screw the avulsed bone back down and restore some if not all of the
ligament function. However, the torn ACL
is rarely able to be “repaired” because during most tears, the ligament tears at its midpoint (like a frayed
rope). Over time, the ligament may
become completely absent. Figure 3. Even if partially intact, the torn ACL sustains
a degree of tissue damage and repair of the original ligament tissue has shown
to provide relatively poor functional results.
‘Reconstruction’ of the ACL alludes to ‘substituting’ for
the ligament by providing a new ligament.
In reality, the surgeon creates a soft tissue substitute called a
“graft” that reestablishes knee stability and provides a scaffold. Miraculously, the patient’s body will
recognize this graft scaffold, populate it with living cells, and permanently
attach it in place. Over a relatively
short time (about 4 to 6 months) this new ‘ligament’ takes on the appearance
and function of the normal ACL. The
functional results of ACL reconstruction are predictably excellent, and the
overwhelming majority of patients are able to get back to the same or higher
degree of athletic activity without pain or instability. Figure 2, Video 2.
Where does the ‘graft’ come from?
Because the tissue
graft is really serving as a temporary scaffold, there are many different
options. In general, there are 2
categories of grafts: those that are
taken from elsewhere in the patient’s body (called autograft) and tissues that are donated from persons who are organ
donors (called allograft). In addition, there are several different
anatomic sources of ‘autograft’ and ‘allograft’. There is no absolute “right” choice for
graft, and the decision is usually based on various patient factors and the
surgeon’s preference. Each has
advantages and disadvantages that will be discussed below.
Patellar Tendon Autograft
The ‘bone-patellar
tendon-bone’ autograft, or “BPTB” is a widely used source for ACL
reconstruction. In general, the surgeon
takes the middle 1/3 of the patellar ligament that runs from the bottom of the
kneecap (patella) to the front of the tibia.
This graft is ‘harvested’ with bone blocks from the patella and tibia
respectively. These bone blocks can then
be secured into bone tunnel ‘sockets’ that are placed at the anatomic location
where the ACL originates on the femur (the ‘origin’) and the anatomic location
where the ACL ends at the tibia (the ‘insertion’). BPTB autograft has been used for a long time
and has an established track record. The
body heals the bony portions of the graft to bone, and the ligament between
serves as the substitute ACL. Advantages
of this graft include its stiffness, strength, and low re-tear rate. It is also rapidly incorporated into the
patient. Potential disadvantages include
temporary or permanent pain at the front of the knee, slight motion losses, and
a more difficult/painful early postoperative course. Figure
4.
Hamstring Tendon Autograft
Five hamstring
tendons help to flex the knee. It is
possible to use one or two of these tendons, from the inner part of the knee to
reconstruct the ACL. Hamstring autograft
has also been in use for a long time and has a very good track record. There is no bone harvested with the hamstring
tendons, and therefore the harvest is easier for the patient with respect to
pain. While the hamstring tendons used
are technically stronger than the BPTB construct, the methods to fix the soft
tissue graft into the sockets is generally less stiff. Advantages to hamstring grafts are that they
are strong, easy and relatively painless to remove, and do not result in
long-term knee pain. Disadvantages
include the fact that the reconstructed ligament may not be quite as stiff,
they are slower to incorporate, and there is controversy about whether there
may be a slight loss in total hamstring strength after they are harvested. For many surgeons, this is the graft of
choice. Figure
5a-b.
Quadriceps Tendon Autograft
A ‘hybrid’ graft
is the quadriceps tendon autograft. This
graft uses a bone plug from the upper kneecap and some of the tendon soft
tissue from the quadriceps (thigh) muscle tendon at the knee. This graft is not as widely used, but has a
very reliable track record. Advantages
are that the quad tendon graft probably results in little long-term knee pain,
it is strong, and uses bony healing at one end.
Disadvantages are that it is slightly more painful to harvest in the
short term, and may not be as stiff as the BPTB.
Allograft
Allograft is
donated tissue from organ donors. There
are many different sources of donor tendons and ligaments that can be used for
ACL reconstruction. In addition to
allograft BPTB and hamstring and quadriceps tendon, other grafts are also used,
such as the tibialis anterior and tibialis posterior. Advantages to allograft is that they do not
require the harvest of normal tissues from the patient with the ACL tear, so
there is no “donor site” pain. The
grafts are also typically robust and strong.
However, there are theoretical risks of disease transmission from the
donated tissue. Nationally, this risk is
about 1:1.5-million for the transmission of HIV, and about 1:470,000 for
hepatitis. The donated allografts DO NOT
result in a significant immune response, and the patient does not have to take
medication or worry about “rejection”.
Allografts have a slightly higher re-rupture rate than BPTB, hamstring,
and quad tendon graft. They have been
commonly used for revision (repeat) ACL reconstructions and the reconstruction
of multiple ligaments, however, the predictably good results of allograft use have
led many surgeons to use these grafts in primary ACL reconstructions, even in
young athletes.
Are there different ways to reconstruct the ACL?
Aside from graft
choice, the other major consideration for the patient and surgeon is whether to
consider a “double bundle” ACL reconstruction.
The native ACL controls both translation
of the tibia under the femur in the front/back plane and also the rotation of the tibia. While the ACL is made of millions of small
fibers, these fibers are generally arranged into two major “bundles”. One bundle is predominantly a translation
stabilizer, and the other a rotation stabilizer. Some surgeons advocate the substitution of
both of the separate bundles to control the translation and rotation more
completely. The reason this is important
is that the single-bundle ACL reconstructed knee is still prone to develop
osteoarthritis over the long term. It is
possible that this is because a single bundle can not restore normal mechanics
to the knee. However, the theoretical
advantages to double bundle reconstruction have not been proven in long-term
studies. At our institution, we perform
double bundle reconstructions when patients request them, and in special cases
that are prone to rotational instability. Figure 6.
When performed by an experienced surgeon, how effective is arthroscopic anterior cruciate ligament (acl) reconstruction for anterior cruciate ligament - acl - tear likely to be and how long will the benefit last?
In the hands of an experienced surgeon, arthroscopic ACL
reconstruction (no matter what graft is used or what technique) is usually very
effective at eliminating instability and restoring comfort and function to the
knee of a well-motivated patient. The
greatest benefits are often the ability to perform the usual activities of
daily living and participating in sports or demanding activities without the
fear of giving way, locking, or pain. As
long as the knee is cared for properly and subsequent traumatic injuries are
avoided, the benefits of the surgery should be permanent.How urgent is arthroscopic anterior cruciate ligament (acl) reconstruction for anterior cruciate ligament - acl - tear?
Reconstruction of the ACL is not an emergency. It is
actually recommended to wait at least a few weeks after the initial injury to
allow the inflammation to decrease and for the patient to regain full knee
range of motion. This will contribute to
a more successful return of motion and muscle strength after the surgical
procedure. Except in special cases, it
is generally advised to rehabilitate the knee first, to see if instability
becomes a true problem before considering ACL reconstruction.
Before surgery is undertaken, the patient needs to:
- Be in optimal health
- Understand and accept the surgical alternatives,
options, risks and benefits
- Have considered, discussed and or attempted
non-operative measures to treat the problem
- Have undergone a comprehensive examination that
includes appropriate diagnostic images such as X-rays and MRIs to define any
additional factors contributing to the problem
- Seek out a surgeon who is experienced in arthroscopic surgery and reconstructing the ACL
What are the most frequent and most serious risks of arthroscopic anterior cruciate ligament (acl) reconstruction for anterior cruciate ligament - acl - tear? How common are they?
The risks of an ACL reconstruction procedure include but
are not limited to the following:
- Infection
- Temporary or permanent injury to the nerves and
blood vessels around the knee
- Excessive joint stiffness
- Pain
- Scarring
- Immune reactions to donated tissue or suture
materials (very low risk)
- Disease transmission from the donated tissue
(exceedingly low risk)
- Failure of the reconstructed ligament
- The need for additional surgeries
- Anesthesia
The experienced and cautious surgical team uses
special techniques to minimize all the above risks. Although adverse events following this
surgical procedure are rare, they can occur and are not completely eliminated.If risks occur during or after arthroscopic anterior cruciate ligament (acl) reconstruction for anterior cruciate ligament - acl - tear how are they managed?
Many of the
risks of an ACL reconstruction can be effectively managed if they are promptly
identified and treated.
- Infections may require a
wash-out of the joint, and rarely removal of the implanted tissue.
- Blood vessel or nerve injuries
are rarely caused by the surgical procedure. Most of theses injuries resolve
spontaneously overtime, but occasionally such an injury may require
surgical repair. It is common to
have decreased sensation around the incision sites. This numbness may or may not entirely
resolve in time.
- Excessive stiffness of the
joint is rare in the person who is cooperative with the postoperative
rehabilitation program, and most of the stiffness will respond to
exercises.
- Pain is a likely response after
a surgical procedure that can be treated with medications, rest, ice, and
compliant rehabilitation. As
healing progresses overtime, the pain will diminish.
- Individuals scar and heal
differently, and it is inevitable that anyone undergoing a surgical
procedure will have scars. To allow
for proper healing and therefore less scarring, the patient should follow
post-operative instructions provided by their surgeon on how to care for
their incisions.
- The risk of disease
transmission from donor tissue is very small, but cannot be
disregarded. All potential donors
undergo strict screening that meets the guidelines of the American
Association of Tissue Banks and the Food and Drug Administration. The tissue is thoroughly tested for HIV
(risk of contracting HIV through donor tissue is less than 1 in 1.67
million), hepatitis (risk of contracting hepatitis is less than 1 in
470,000), and other infectious diseases.
The transplant is then prepared and processed to prevent the
transmission of bacteria and viruses according to United States Federal
guidelines.
If a patient has questions or concerns about the “normal”
course after surgery, the surgeon should be informed as soon as possible and be
available to explain the expected course and outcome.
Surgery for Anterior cruciate ligament - ACL - tear at the University of Washington, Department of Orthopaedics and Sports Medicine, Seattle, Washington
If you are interested in making an appointment to discuss this procedure in Seattle, you can request an appointment using our online referrals website. To request a referral online, please click here. You can also call 206-543-1552 or 425-646-7777 to make an appointment. Our clinical center is located in Seattle Washington, USA
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