1. ACL injuries are common in sports and often occur during landing, pivoting, or deceleration. Female athletes have higher risk due to neuromuscular imbalances. 2. Autografts used in ACL reconstruction include the patellar tendon and hamstring tendon. Allografts also exist but have disadvantages. 3. Post-op rehabilitation follows 4 phases focusing first on protection then controlled training before intensive training and return to play. Functional tests assess readiness.

1.  
By Peter Batz, SPT

2.  The occurrence of injury to the Anterior Cruciate
Ligament (ACL) is reported to be as high as 46% of all
knee ligament injuries in sports
 Most anterior cruciate ligament (ACL) injuries occur by
noncontact mechanisms
 Anterior cruciate ligament injuries often occur during
landing from a jump, decelerating, or pivoting on one foot
while running.

3.  Female athletes who participate in jumping and pivoting sports are 4
to 6 times more likely to sustain an ACL injury than male athletes.
 When women land, decelerate, and pivot, increased knee instability-
due to four neuromuscular imbalances commonly observed in
female athletes-contribute to the ACL injury mechanism:
o 1. Ligament dominance (decreased dynamic neuromuscular control of the
joint, which is related to the knee abduction component of the injury
mechanism)
o 2. Quadriceps dominance (increased quadriceps recruitment and decreased
hamstring strength and recruitment, which is related to the extended knee
position component of the injury mechanism)
o 3. Leg dominance (side-to-side differences in strength, flexibility, and
coordination, which is related to the asymmetrical foot weighting component
of the injury mechanism)
o 4. Core instability (increased trunk motion, which is related to the foot
displaced away from the body center of mass component of the injury
mechanism).
 These imbalances cause female athletes to treat their knee joints as
a ball and socket joint while male athletes knees behave more like a
hinge joint.

4.  Autografts
o Patellar Tendon
o Hamstring Tendon
 Allografts

5.  When selected, the central 1/3 of the patellar tendon is
removed (~9-10mm long) with a block of bone at the
sites of attachment on the kneecap and tibia.
 Advantages
o Length of the patellar tendon is about the same as the ACL
o Bone ends of the graft can be placed into the bone where the
ACL attaches
• This allows for “bone to bone” healing
 Disadvantages
o Risk of patellar fracture or tendon tear following surgery
o Anterior knee pain is commonly reported post surgery

6.  When used in ACL surgery, two of the tendons of the
hamstring muscles are removed and bundled together to
create new ACL
 Advantages
o Anterior knee pain is not present as it is commonly with a
patellar graft
o Smaller incision to obtain the graft
 Disadvantages
o Fixation of this graft can be difficult as there are no bone ends
with this graft
o Longer period of healing time is necessary (longer recovery
time)

7.  Allografts come from a donor tissue, such as a cadaver.
 More commonly used in recreational athletes than in
competitive athletes.
 Advantages
o Using allografts allows for decreased operative time
o No need for multiple incisions to obtain the graft, leading to
decreased risk of infections
 Disadvantages
o Previously there was a risk of disease transmission when
cadavers were not screened properly.
• Still a risk today but much less likely
o Decreased strength of tissue compared to autografts

8.  Rehab can be divided into 4 phases
o Protection and controlled ambulation
o Controlled training
o Intensive training
o Return to play

9.  Usually last from 4-6 weeks
 Goals during this phase:
o Control pain/swelling
o Improve ROM
o Quadriceps activation
o ADL activities
 Functional Training
o Strengthening noninvolved limb
o Trunk and hip basic core stability exercises
o Cardiovascular (upper-body ergometer)
 Aquatic Therapy
o Gait training
o Simple exercises (ROM, balance)

10.  Begins from 4-6 to 8-12 weeks
 Criteria for this phase:
o Minimal pain/swelling
o Near full ROM
o Good patellar mobility
o Sufficient quadriceps control
o Normal gait pattern
 Goals for this phase:
o Prepare basic soccer neuromuscular control
o Prepare the player for the more intense phase 3
 Functional training to include:
o Core stability
o Balance training
o Strengthening involved limb (open/closed chain), use of thera-bands for resistance.
o Plyometrics
o Cardiovascular training (bike)
o Flexibility
 Aquatic Therapy
o Progression toward water running
o Flexibility/ROM
o Simulated basic soccer drills (heading the ball)

12.  Begins at 8-12 to 16-24 weeks
 Criteria to enter this phase:
o No pain/swelling
o Full ROM
o Good neuromuscular control at knee, hip, and trunk
o Quadriceps and hamstring strength >75% of noninvolved limb
o Good hop/jump and landing techniques
 Goals for this phase:
o Optimize soccer-specific neuromuscular control
o Prepare the player for return to team practice
 Functional training should include:
o Core stability/strengthening
o Strength training (body-machine exercise)
o Cardiovascular soccer specific training (interval, bike)
o Flexibility
o Water running: endurance training

16.  Phase 4 consists of two parts
o Return to reduced soccer practice
o Return to full soccer practice

17.  Can begin at 16-24 weeks or later
 Criteria to start this phase:
o No pain/swelling
o Symmetrical ROM
o Optimal soccer-specific neuromuscular control
o Quadriceps and hamstring strength >85% of noninvolved limb
o Hop index >80% of noninvolved limb
 Goal for this phase
o Bring the player back to unrestricted team practice, with full
possession of his/her soccer skills and conditioning
 Functional training to be done:
o Core stability/strengthening
o Strength training (body machine exercises) focused on addressing
remaining deficits
o Flexibility

18.  Same time frame
 Criteria for this phase:
o No pain/swelling
o Symmetrical ROM
o Optimal soccer-specific neuromuscular control
o Quadriceps and hamstring strength >95% of noninvolved limb
o Hop index >90% of noninvolved limb
o Final preparation of the player for the needs and demands of
competitive soccer.
 Functional Training to include:
o Continuation of additional training in the form of soccer specific
warm-ups.

19.  Hop Tests (4)
o Single hop for distance
o 6-m timed hop
o Triple hop for distance
o Crossover hop for distance
 Y-Balance Test
 Star excursion test

20.  For single leg hopping, stand on one foot with your toes
behind a marked line on the floor.
 Hop forward as far as possible, landing on the same foot from
which you took off
 Measure and record the distance you hopped in centimeters
o Must maintain landing for a minimum of 2 seconds
 Repeat the test a total of three times for both legs, recording
the distance hopped each time
 Results:
o The expected values for the injured leg in the single hop test are
137cm for males and 121cm for females at 4 months post surger. At
the 6 month mark, norms for the single hop test are 149 cm and 133
cm for males and females.

21.  For single leg distance hopping, stand on one foot with
your 6 meter line extending out in front of you
 Hop as quickly as you can on one foot until you reach
the end of the 6 meters
 Record the time it takes for you to hop 6 meters on one
foot.
 Results:
o Expected times 4 months after surgery are 2.7 seconds for
males and 3.0 seconds for females. Six months post ACL
surgery, the expected times are 2.4 seconds for males and 2.8
seconds for females.

22.  For straight line triple hopping, stand on one foot with
your toes behind a marked line on the floor
 Hop forward as far as possible for three consecutive
hops
 Measure and record the distance hopped in centimeters
 Repeat the test three times for both legs, recording
distance hopped each time
 Results:
o The norms at the 4 month post-op mark are 401cm for males
and 343cm for females. The expected norms at the 6-month
point after surgery are 420cm for males and 363cm for females.

23.  Mark a line on the floor about 6 meters long
 Stand on one foot and hop forward and over the line
 Continue hopping in a zig-zag pattern over the line for
three hops
 Record the distance hopped in centimeters for the
injured and uninjured leg.
 Results:
o Expected values at 4 months post-op are 358cm for males and
305cm for females. At the 6 month point it is 377cm for males
and 337cm for females.

24.  Used to determine abnormality between surgical and
non surgical leg post ACL repair.
 Distance hops:
o (mean involved leg/mean uninvolved leg) x 100% = LSI
 Timed hops:
o (mean uninvolved leg/mean involved leg) x 100% = LSI
 Abnormal LSI = < 85%

25.  https://www.youtube.com/watch?v=iNzGCet0Ll0

26.  Study of Y-balance test was performed on 184 collegiate
athletes
 It was determined that an anterior reach asymmetry of >
4cm between legs was the optimal cut-point for
predicting injury
o (Sensitivity=59%; Specificity=72%)
 This study suggested that the composite score was not
related to injury risk
o It was suggested that this was due to their needing to be cut off
scores for athletes need to be based on the sport which they
play

28.  Used to assess dynamic postural control
 Test is shown to have high inter and intra-rater reliability.
 Study by Herington et al. found that in ACL deficient
patients both their injured and uninjured legs showed
deficits when compared to the control group.
 It was thought that this may be due to a postural control
deficit which may make ACL deficient patients more
predisposed to ACL injury or re-injury.

31.  1. Herrington L, Hatcher J, Hatcher A, McNicholas M. A comparison of star excursion
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 5. Sears B. Single Leg Hop Testing. Available at:
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 6. Braegelmann B, Corbo J, and Himmerick R. Lower Extremity Functional Testing: Is my
Athlete Ready to Return to Sport? Available at:
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