ACL Injuries

Scroll down for: Overview, Symptoms, Diagnosis, Treatment, Recovery & FAQ’s

Overview

The knee is a commonly injured joint.

Within recent years, the increase in ACL (anterior cruciate ligament) injuries has been remarkable. Trauma to this ligament within the knee can be serious, and injuries to it usually occur during athletic activity.

Why are knee injuries so common?

The knee is particularly vulnerable to injury. It is the joint between the two longest bones of the body, and the entire weight of the body is transferred to the foot through the knee. The knee is also more prone to injury because its stability decreases as it bends. The menisci and the ligaments provide less effective support to the bent knee.

What does the inside of the knee look like and where is the ACL?

The knee joint contains bones, ligaments, muscle tendons, cartilage, nerves, and blood vessels. A fibrous joint capsule made of collagen surrounds the joint and encircles the end of each bone to give the knee stability.

Symptoms

What are the signs and symptoms of an ACL injury?

A twist or strain has occurred which causes the following signs:

“Pop” – Many patients, but not all, will hear or feel a “pop” when the ACL tears.
Immediate onset of swelling – This is an indication that there is bleeding from the injured ligament.
Pain – Most patients experience quite a bit of pain with an ACL injury.
Instability – Patients often describe a buckling or unstable sensation in the knee.

Diagnosis

How is an ACL injury diagnosed?

The orthopaedic surgeon will want to know the history of the knee injury and will determine if the signs and symptoms of an ACL injury are present.

After taking a history, the orthopaedic surgeon will perform a physical examination. The doctor will perform manual tests on the knee to determine the amount of instability that exists.

The Lachman Test, Anterior Drawer Test, and Pivot Shift Test are exams the doctor may use to see how much the tibia moves in relation to the femur.

Pain, swelling, and muscle spasms in the early stages of an injury may make it difficult for the doctor to diagnose the degree of instability with manual tests. An arthrometer, a machine that measures joint looseness in the knee, may be used.

X-rays can reveal signs of bone fractures, chips, or arthritis. Since X-rays can only show bone, a Magnetic Resonance Image (MRI) may be ordered to assess damage to soft tissue such as ligaments, tendons, and cartilage. An MRI is a non-operative procedure that allows the surgeon to determine the amount of damage to the ACL and any other structures of the knee.

If further testing is needed to clearly evaluate the problem, an arthroscopy may be recommended. During an arthroscopy, a tiny fiberoptic scope is inserted into the joint. The doctor uses this scope to visually assess the damage. In most cases, a diagnosis can be made without using this surgical procedure.

Treatment

How is an ACL injury treated?

The common recommendation for immediate treatment of an ACL injury is the well-known rule of RICE:

Rest the knee by using crutches and keeping weight off of it
Ice the knee
Compress the knee with a wrap
Elevate the leg

These measures will help control swelling. The doctor may also drain the joint of excess fluid to reduce pressure. After the initial injury symptoms have subsided and the diagnosis has been established, the orthopaedic surgeon will look at the history of the injury and the patient’s activity level to determine what treatment is best for the patient.

How old is the knee injury?
Does the patient continue to have recurrent instability?
How old is the patient and what types of activities does this patient enjoy?
What level of activity does this patient wish to return to?
Are there other associated injuries?

The two basic treatment choices for an ACL injury are:

Non-Operative treatment with rehabilitation and bracing, and Surgical Treatment

Non-Operative

The ACL does not reliably heal well on its own. Although this is true, about one-third of all patients will do well without surgery. A patient who does well without surgery is:

Older or less active
One who decreases his or her activity level
One who avoids pivoting sports

These patients can expect a fair to good outcome just by learning to cope with their injury.

Patients who do not do well with non-operative treatment are usually described as:

Younger or active patients
Those who like to participate in pivoting sports

These patients are more at risk for reinjury. For these people, the likelihood of further damage to other ligaments or cartilage is quite high. A common reinjury is tearing a meniscus, which can lead to degenerative arthritis in the years to come.

Patients who are less active and do not participate in pivoting sports can continue to have a high quality of life with a good rehabilitation program. A partial tear to the ACL is usually treated in this manner.

Surgical Treatment

Patients for whom surgery is generally recommended:

Active individuals who participate in any sport with pivoting – such as soccer, tennis, basketball, football, or skiing
Patients who continue to experience instability after going through a rehabilitation program
Those with injuries involving more than one ligament

It is important to consider the patient’s commitment to the rehabilitation program following an ACL surgical procedure. This is especially critical if a meniscal repair is also required. The patient must agree to carefully follow the recovery timetable outlined by the doctor.

The timing of an operation is important to prevent stiffness after surgery and obtain the best results. It is helpful when:

Range of motion is adequate
Swelling is reduced
Quadricep muscles are functional

It often takes about three weeks for the knee to reach this point.

Is there a simple way to repair the damaged ACL without a reconstruction?

In a direct repair the ends of the torn ligament are sewn together. This procedure is usually not recommended, as the ends of the ligament do not heal reliably. Direct repairs of the ligament to the bone may heal; however, this, also is not always reliable.

Recovery

Following surgery, the patient will be started on a structured rehabilitation program.

For more specific information please click here: Post Op Care

How is an ACL injury treated?

Patient commitment and involvement are essential for a good functional result. The specific exercises and program timelines vary depending on the graft source used, and whether surgical repair to other injured structures was performed.

The first phase of rehabilitation emphasizes range of motion, which is critical to avoid knee stiffness.

A continuous passive motion (CPM) machine is used in the recovery room and the first night. This machine gently and steadily bends and straightens the patient’s knee.
Crutches are used for the first 7 -10 days after surgery for comfort. Full weight bearing would be painful.
Riding a stationary bike without resistance and pool exercises to increase motion usually begin about 2 weeks after the surgery.
Driving is allowed when the patient is comfortable and has mobility, often as early as 2 weeks after the operation.

The patient returns for an office visit about 2 weeks after the surgery so the incision and range of motion can be checked.

The second phase of rehabilitation incorporates strengthening and usually begins about 6 weeks after surgery.

A sports cord (an elastic resistance strengthening tool) and the treadmill are initially used.
Use of a stair-stepper or elliptical trainer is added at about 8 weeks.
Strengthening using weights is allowed at 2 – 3 months.

The third phase of rehabilitation adds sport-specific exercises.

Running is allowed at 3 months.
Pivoting and twisting activities can begin at 4 to 5 months.

This phase is usually customized for the patient’s sports and activity level.

The final phase of rehabilitation involves a supervised return to sports.This usually occurs approximately 6 months after reconstructive surgery.

Are knee braces used after ACL reconstruction?

Bracing after an ACL reconstruction depends on the surgeon’s preference. Some surgeons use no bracing while some use braces only during the rehabilitation phase. Still others recommend that patients always use a brace.

A post-operative brace is often used immediately after surgery. This is a large, sturdy brace that limits motion and helps protect the repair from an unexpected fall or twist. This type of brace is easily adjusted to accommodate the changes in the knee as swelling subsides.

A functional brace is lighter and less bulky and is often used during later stages of rehabilitation to protect the ACL reconstruction. Some surgeons recommend continued use of a custom-fit functional brace as a “safety-belt” during sports after this type of surgery.

What type of follow-up is done after an ACL reconstruction?

Usually, about a year following surgery, the doctor will evaluate the knee to measure the final results of the reconstruction in these areas:

Motion
Stability
Symptoms such as pain or swelling
How well the knee functions in daily living
Whether or not the patient has been able to return to sports

Some of these follow-up exams have shown that 90 to 95% of patients with ACL reconstructions have good to excellent results.

What types of complications can occur with an ACL reconstruction?

Stiffness in the joint, or lack of extension, is the most common complaint. This is why it is important to wait for motion to return and swelling to go down before surgery, and to follow the rehabilitation instructions given by the doctor and therapist.

Failure of the graft, reinjury to the ACL, or injury to other structures in the knee are possible, and can cause recurrent instability. Blood clots and infection in the joint are very rare occurrences.

FAQ

Can the ACL heal by itself?

Some knee ligaments, such as the medial collateral ligament (MCL), heal reliably without surgery. Some partially torn ACLs, particularly in children and adolescents, may also heal without surgery. However, a complete tear of the ACL rarely heals. This is probably due to the amount of energy involved in the injury, the lack of blood supply, and the interior location of the ACL. The torn ACL may scar back to the intact PCL within the knee, but this rarely returns stability to the knee. In fact, even when the ends of a torn ligament are sutured together (called a primary or direct repair), the ligament does not reliably heal. Therefore, surgery for a complete ACL tear (an ACL reconstruction) involves replacing the ACL with other tissue (a graft).

Is surgery always needed for an ACL tear?

Surgery is not required for all ACL injuries. Partial tears, in which a physical examination shows a relatively stable knee, may be treated with bracing and rehabilitation. Even some patients with complete ACL tears do not need reconstruction. These “copers” are typically older patients with lower physical activity, who do not participate in pivoting and cutting activities.

Why should the ACL be reconstructed?

One reason to reconstruct the ACL is to provide knee stability that allows for return to activities and sports. Another reason is to provide knee stability in order to prevent more injury, such as a meniscal tear, which may eventually lead to degenerative joint disease.

Is an MRI needed to diagnose an ACL tear?

An MRI is not always required to diagnose an ACL tear. An ACL tear can be accurately diagnosed with a physical examination. However, when the knee is very swollen and painful, an accurate examination can be difficult. Also, an MRI can be useful to reveal other associated injuries such as meniscal tears, a PCL tear, or injury to other supporting structures.

Which is the best graft to use for an ACL reconstruction?

There are advantages and disadvantages to the many technical aspects of an ACL reconstruction including the type of graft, methods of securing the graft, and rehabilitation protocols. There is no clear consensus as to which graft is best. In the end, the surgeon’s experience with the chosen technique and the patient’s commitment to the rehabilitation program are probably more important factors in a functional outcome.

When can I play sports again after ACL reconstruction?

Rehabilitation programs after ACL reconstruction are constantly evolving, shortening the return to sports. Most patients can start to return to their sports about 6 months after reconstruction.

ACL Injuries New York, ACL Injuries Specialist Dr Glashow