How can you injure the ACL?
The most common mechanism of injury of the ACL is the combination of sudden stopping and pivoting or twisting on the leg. The ACL can also injure in contact sports where the player is clipped forcing the knee into an abnormal position.

Who is at risk?
There are a multitude of scientific studies indicating that females are at a 4-6 times higher risk of ligamentous knee injuries compared to their male counterparts. A high percentage of these injuries occur in non-contact sports, but also with sports involving pivoting, cutting and landing from a jump.

Signs and symptoms that you may have an ACL injury:
The player will most likely experience a "pop" following a feeling of instability, pain and increased swelling of the knee joint. Over the next several hours, pain will increase and it may even be difficult to walk. Later, a feeling of giving way or buckling in the knee joint may be reported.

Treatment Options for the ACL:

1. Conservative Treatment: Some patients, particularly those over the age of 30 who are not highly active, may not require surgery. These patients can function very well as long as they avoid high risk sports such as skiing, basketball, soccer and football. Wearing a knee brace may help stabilize the knee, improve function and can help prevent re-injury. These patients should participate in physical therapy to restore strength, power and endurance in the knee joint.
   
2. Limited Arthroscopic Surgery: ACL injuries may also be accompanied by injuries to additional structures of the knee joint including torn meniscus or fragments of the articular cartilage creating a loose body in the joint. Symptoms include the knee joint locking, pain and swelling. Arthroscopic surgery can remove the torn meniscus or loose body improving the patient's pain and eliminating locking; however will not resolve the instability of the knee associated with the torn ACL.
   
3. ACL reconstruction: ACL reconstruction involves replacing the ACL with a tendon (or a graft) with another structure within the knee. There are generally three different grafts that orthopedic surgeons use. The surgeon chooses the type of graft depending on the patient's age, activity level and personal preference. The rehabilitation is similar for all three grafts.

ACL Reconstruction (3 general types):

1. Middle third patellar tendon: the tendon that connects the knee cap to the shin bone (tibia).
   
2. Hamstring tendon: the tendon of the back of the thigh muscle take from the inner thigh to the back of the knee is used.
3. Allograft: tendon grafts taken from a cadaver.

Rehabilitation after surgery (2 protocols):
There are several different protocols that orthopedic surgeons recommend following surgery. Listed below are examples of activities on a timeline (accelerated for athletes vs. non-accelerated for patellar third reconstruction) that your doctor may prescribe. Please be advised that this is only a sample protocol and your doctor will recommend what is best for you. It should also be noted that an accelerated protocol will most likely not allow for a quicker return to competitive sport any sooner than non-accelerated protocol.

Some examples of exercises:

Non-Accelerated Protocol	Week 1	Week 2	Week 3	Week 4	Week 5	Week 6	Week 7	Week 12-16	Week 16-24
Phase 1 (Week 0-2)
Quadriceps Setting
Patellar Mobilization
Heel Slides
Sitting Heel Slides
Heel Prop
Prone Hang
Straight Leg Raise
Hip Abduction
Ankle Pumps
Phase 2 (Week 2-6)
Stationary Bicycle
Water Workout (Optional)
Aqua Jogger Exercise
Flutter-kick swimming
Standing Hamstring Curl
Standing Toe Raises
1/3 Knee Bends
Wall Slides
Phase 3 (Week 6-12)
Balance Training
Hamstring Stretch
Quadriceps Stretch
Calf Stretch
Phase 4 (Week 12-16)
Aerobic Conditioning:
Stairmaster
Elliptical/Nordic Track
Swimming
Seated Leg Press
Resisted Hamstring Curls
Hip Abduction/Adduction
Roman Chair
Calf Raise Machine
Single Leg Step Up/Down
Single Leg Wall Slide
Single Leg Squat to Chair

Accelerated Protocol	Week 1	Week 2	Week 3	Week 4	Week 6	Week 8	Week 10	Week 10-16	Week 16-24
Phase 1 (Week 0-2)
Ankle Pumps
Straight Leg Raises (3-way)
Quadriceps Setting
Hamstring Stretch
Mini-squats
Weight Shifts
Patellar Mobilization
Prone Hang
Multi-angle Isometrics
Standing Hamstring Curl
Phase 2 (Week 2-4)
Leg Press
Front and Side Lunge
Half Squat
Stationary Bicycle
Pool Program (Optional)
Lateral Lunge
Lateral Step-ups
Front Step-ups
Phase 3 (Week 4-10)
Hamstring Curls
Hip Abduction/Adduction
Hip Flexion/Extension
Wall Squats
Calf Raises
Balance Training
Backward Running
Forward Running
Balance with Throwing
Plyometric leg press
Pertubation Training
Walking Program
Aerobic Conditioning
Plyometric Training
Phase 4 (Week 10-16)
Continue with Strength and Balance Training as above
Phase 5 (Week 16-22)
Return to Sport

Prevention of ACL injury:
As previously stated, females are at a greater risk of injury. Furnace Brook Physical Therapy has developed a strength, conditioning and plyometric jumping program proven to decrease the incidence of this particular type of injury. For more information please refer to "Raise the Roof" program listed under specialty programs.