Diagnosis and Treatment of ACL
Injuries
Jeff Martin DO
Author has no conflicts of interest to
disclose
Goals:
Improve knowledge and treatment of ACL tears
from injury through treatment and rehabilitation.
Introduction
• 150,000-400,000 ACL tears annually
• Chronic ACL deficient knees associated with
– chondral injuries
– complex unrepairable meniscal tears
– relation with arthritis is controversial
• 2nd most commonly tested topic on yearly
Orthopedic resident inservice test over the
last ten years
The Female Athlete
• Women athletes have 4-6x rate of ACL injuries
then males
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Increased Q angle
Valgus Leg alignment
Effects of estrogen
Small ACL width
Narrow femoral notch
Increased Joint Laxity
Jump patterns (extended knee with greater hip
adduction moments)
• Focus of ACL injury prevention programs which have shown
decreased incidence of ACL tears
Prevention
Level 2 evidence shows that high intensity
plyometrics coupled with balance training and
strengthening improves neuromuscular
feedback
This reduces ligamentous strain during pivoting
and landing activities
For the training regimen to be effective, a
minimum of 1 session per week for 6 weeks needs
to be implemented
• neuromuscular training / plyometrics (jump
training)
• land from jumping in less valgus and more
knee flexion
• increasing hamstring strength to decrease
quadriceps dominance ratio
Anatomy
• Primary function is to prevent anterior
translation of the tibia
• Secondary role in preventing internal rotation
of tibia
Anatomy of ACL
 ACL attachments:
 Arises from posteromedial corner of the lateral
femoral condyle in the intercondylar notch
 Broad insertion at anterior intercondylar
portion of the tibia
 length of 38 mm (range 25 to 41 mm)
 width of 10 mm (range 7 to 12 mm)
 ACL is intra-articular and extra-synovial
 Blood supply is the middle genicular artery
 Due to relatively poor blood supply, ACL has little
intrinsic capacity to heal
ACL composed of Two Bundles
Anteromedial
• Tight in Flexion 45-60
• Controls anterior
Translation
Posterolateral
• Tight in Extension
• Rotator Stability and
anterior motion
Mechanism of Injury
• typically, the ACL is torn in a noncontact
deceleration situation that produces a valgus
twisting injury
• this usually occurs when the athlete lands on the
leg and quickly pivots in the opposite direction
• Other Mechanisms
- hyperextension
- marked internal rotation of tibia on femur
- pure deceleration
Presentation
• Classic “pop”
• 70 - 80% of acute hemarthroses are secondary
to ACL injury
Physical Exam ACL
• Quadriceps avoidance gait
– most patients will alter their gait in
order to avoid anterior displacement
of the tibia which occurs with
quadriceps contraction
• between 0 to 45 deg of flexion,
contraction of the quadriceps will
cause anterior translation of the
tibia (which is normally resisted by
the ACL)
• Lachman (most sensitive)
• Anterior drawer
• pivot shift (most specific, usually
done under anesthesia)
• Classic O’Donoghue Triad (Terrible Triad) rare
– ACL, MCL, medial meniscus
• Lateral meniscus
– Acute
• Medial meniscus
– Chronic
• At the time of injury approximately 1/3 of
patients will have meniscal tears
Imaging ACL Tear
• Plain radiograph
– Segond (capsular sign)
• Small fracture at periphery of proximal lateral tibia
Imaging
• MRI
• ACL Tear best seen on sagittal view
• Osteochondral contusion @ middle third of the lateral femoral
condyle and posterior third of the lateral tibial plateau
• 50% injuries
Treatment
• Nonoperative
– low demand patients with decreased laxity
– increased meniscal/cartilage damage linked to
• loss of meniscal integrity
• frequency of buckling episodes
• High level of activity (e.g. jumping, cutting, side-to-side
sports, heavy manual labor)
Operative (ACL reconstruction)
• Indications
• in younger, more active patients (reduces
incidence of mensical or chondral injury)
• older active patients (Age >40 is not
contraindication if high demand athlete)
• ACL reconstruction failure
• Attempted ligament "repair" has high failure
rate
Surgical Techniques
• 2006 study with BTB (minimum 13 year follow
up) showed 79% of patients had radiographic
evidence of degenerative changes
• 2007 meta-analysis reported only 33-41%
normal knee scores after ACL reconstructions
Tunnel Placement
• Transtibial Technique has tendency to place femoral tunnel
vertical=less rotational stability
• Anatomic ACL reconstructions- place tunnnels in native
femoral and tibial attachment sites
Double Bundle vs Single Bundle
• Some biomechanical evidence suggests that
double bundle reconstructions result in better
restoration of knee stability
• No clinical evidence of difference
Surgery
• Arthroscopic Assisted ACL Reconstruction
with Patellar tendon Autograft
– 1) If certain ACL is nonfunctional (side to side
difference of >5mm), harvest autograft before
the arthroscopy. If not certain, evaluate the
knee arthroscopically first.
Surgery
• 2) The middle third
(~10mm) of the patellar
tendon is harvested with
bone plugs from the tibia
and patella. Bone plugs
are trimmed to facilitate
passage through the
osseus tunnel. Holes are
drilled in the bone plugs to
pass nylon sutures.
Arthroscopy.
Surgery
• 3) Arthroscopic Soft tissue
debridement of ACL attachment
sites
• 4) Position and prepare osseus
tunnels
– Length of tibial tunnel is calculated
– Cannulated core drill used to create
a tibial tunnel and then a femoral
tunnel for transtibial technique
– Accessory medial portal can do
tibial or femoral tunnel first.
• 5) Graft implantation and
fixation
– Pin is retrograded through
tunnels and out anterolateral
thigh
– suture on graft is threaded
through the pin and the
suture and graft are pulled
through tunnel into the joint
– Bone plugs are fixed by
interference screws and
inserted flush with the bone
tendon junction
Surgery
• 6) Knee flexed through full ROM, pivot and lachman
tests performed
– Core of bone from the tibial tunnel used to fill bony defect
of the patella
– Patellar tendon loosely re-approximated to prevent any
palpable gaps w/out shortening the patella tendon
– Peritenon, subcutaneous tissue, skin closed in separate
layer
Graft Options in ACL Reconstruction
Autograft
Bone-patella tendonbone
Hamstring
Quadriceps
Allograft
Bone-patella tendon-bone
Hamstring
Quadriceps
Tibialis anterior
Tibialis posterior
Achilles tendon
Fascia lata
Peroneus longus
ACL Autografts
 Advantages:
 No issue regarding cost
and availability of graft
 No risk of disease
transmission
 Good potential of bonegraft interface
 No tissue rejection
 Disadvantages
 More wound pain
 More prominent scar
 Longer surgical time
 Donor site morbidity
ACL AutoGrafts Load to Failure
• Native ACL 2160N
• 10mm BTB 2977N
• Quadrupled Hamstring
4090N
• Quadriceps 2352 N
1 N = 1 kg⋅m/s2
Bone-patella tendon-bone
For past few decades,
Gold Standard for ACL
Reconstruction
Clinical Studies have not
shown significant
differences between
grafts
Ease of harvest
Bone-to-bone healing
with secure fixation
Bone-patella tendon-bone
Disadvantages
Potential negative effect on
the knee extensor
mechanism
Anterior knee pain / kneeling
pain
Risk for patella fracture
Anterior knee numbness
Hamstring tendon
 Combined semitendinosus
and gracilis hamstring
tendons
 Less anterior knee pain, no
disruption of knee extensor
mechanism, and less risk
for patella fracture
 Quadrupled Hamstring
strongest Graft 4090N
nearly double native ACL
Hamstring tendon
• Potential Limitations:
• Slower soft-tissue graft-tunnel healing (when
compared to bone-to-bone healing with patella
tendon grafts)
• Potential for tunnel widening and graft laxity
• Functional hamstring weakness from graft
harvesting
• Some studies show lower return to pre-injury
activity levels
Quadriceps tendon
Noted to be more
difficult to harvest
Potential for anterior
knee pain
Persistent quadriceps
weakness?
Thicker then patellar
tendon
Graft Selection in Anterior Cruciate Ligament Reconstruction Walter R. Shelton, MD
Bryan C. Fagan, MD JAAOS 2011;19: 259-264
Allografts
 Wide range of graft sources and availability
 Availability of larger grafts
 Quicker surgical time
 No donor site morbidity
 Lower incidence of post-operative arthrofibrosis
 Faster immediate post-operative recovery and less postoperative pain
 Easier rehabilitation
 Useful in revision ACL reconstruction procedures
ACL Allografts
 Disadvantages
 Expensive ($1500)
 Risk (minimal) of tissue rejection
 Risk (minimal) of disease transmission
 Relatively longer healing time of the graft
 Variability in mechanical properties of ACL allografts
 In some studies higher failure rates
When irradiated and chemically processed grafts were
excluded, then failure rates were no longer statistically
significant
Gamma Irradiation of ACL Allografts
 One of the most widely utilized forms of secondary graft sterilization is
gamma irradiation
 Known pathogens include HIV, hepatitis, bacteria, and fungus
 Susceptibilities:
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Non-spore-forming bacteria: 0.5 Mrad
Bacterial spores: 2.1 Mrad
Yeast/Mold: 0.8 Mrad
HIV: 1.5 – 4 Mrad
 Irradiation doses > 2 Mrad have demonstrated decreases in
biomechanical properties of the allograft
 Increased elongation and decreased stiffness, maximum force, strain, and
maximum stress
 Disruption of collagen organization and cleaving of polypeptide bonds
 Studies have shown that lower irradiation levels (1.0 – 2.0 Mrad) do not
compromise graft biomechanical properties
 These doses will not eliminate HIV, hepatitis, and spore-forming bacteria.
 Demonstrates the importance of adequate screening
ACL Tears in Children
• Treatment in Children (< 14 yrs with open physis)
– strongly consider operative
• activity limitation impractical
• transphyseal soft tissue grafts rarely lead to growth
disturbances
• avoid transphyseal metallic fixation
• Fixation outside the physis (over the top techniques)
Rehab
ROM
Immediate ROM is more beneficial to a healing graft
than delayed motion
Immediate ROM and CPM have not been shown to
endanger ACL grafts
ROM helps prevent scar tissue formation in the
intercondylar notch and elsewhere
Knee extension loss is one of the more common
complications after ACL recon
Immediate, full, passive, terminal extension is required
Rehab
Weight Bearing
At least partial weight bearing should begin initially
to ensure that proper gait sequence and cadence can
be performed
Immediate weight bearing has been shown to decrease
incidence of anterior knee pain
Pain should be controlled to allow progression to full
weight bearing (avoids quadriceps avoidance gait)
Some protocols limit weight bearing after soft-tissue
fixation methods
– early rehab
• focus rehab on exercises that do not place excess stress on
graft
– appropriate rehab
» isometric hamstring contractions at any angle
» isometric quadriceps, or simultaneous quadriceps and
hamstrings contraction
» active knee motion between 35 degrees and 90 degrees of
flexion
» emphasize closed chain (foot planted) exercises
– avoid
» isokinetic quadricep strengthening (15-30°) during early rehab
» open chain quadriceps strengthening
Outcomes
An evaluation of NFL wide receivers and running
backs after ACL reconstruction showed only 80% of
the athletes returned to play
Of those returning, there was a 30% decrease in
statistical performance
Revision reconstructions result in 60% return to
athletic activity, but with decrease level of
performance
Most common reason for ACL recon failure?
Technical failure (tunnel placement)
Single stage vs two stage revisions are dictated by
tunnel quality and degree of osteolysis
Complications
• Infection
– septic arthritis
• Staph aureus most common
– treatment
• immediate arthroscopic I&D
• often can retain graft with multiple I&Ds and abx (6 weeks minimum)
• Loss of motion & arthrofibrosis
– preoperative prevention
• be sure patient has regained full ROM and swelling gone before you
operate
– operative prevention
• proper tunnel placement is critical to have full range of motion
– postop prevention
• aggressive cryotherapy (ice)
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Infrapatellar contracture syndrome
Patella Tendon Rupture
RSD (complex regional pain syndrome)
Patella fracture
Hardware failure
Tunnel osteolysis
Late arthritis
– Thought to be related to meniscal integrity
• Local nerve irritation
– saphenous nerve
• Cyclops lesion
– fibroproliferative tissue blocks extension
– "click" heard at terminal extension
Thank You
References
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Graft Selection in Anterior Cruciate Ligament Reconstruction Walter R.
Shelton, MD Bryan C. Fagan, MD J Am Acad Orthop Surg 2011;19: 259264Copyright 2011 by the American Academy of Orthopaedic
Surgeons.BiomechanicsMay 2011, Vol 19, No 5259Review Article
Does ACL Reconstruction Alter Natural History? A Systematic Literature Review
of Long-Term Outcomes Chalmers P et al. J Bone Joint Surg Am, 2014 Feb
19;96(4):292-300.
MR Imaging of Complications of Anterior Cruciate Ligament Graft
Reconstruction. Bencardino J et al. Radiographics, 2009 Nov Vol 29 2115-2127
Nonsurgical or Surgical Treatment of ACL Injuries: Knee Function, Sports
Participation, and Knee Reinjury The Delaware-Oslo ACL Cohort Study.
Grindem H et al. Bone Joint Surg Am, 2014 Aug 06;96(15):1233-1241.
Comparison of Functional Outcome Measures After ACL Reconstruction in
Competitive Soccer Players, A Randomized Trial. Mohammadi F et al. Bone
Joint Surg Am, 2013 Jul 17;95(14):1271-1277.
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