Evaluation and Management of Knee
Injuries
2007 Update
Courtesy of John Whiteside, MD
Knee is not the most commonly injured joint
(ankle), but it has…
Greatest susceptibility to wear and tear,
inflammatory and septic arthritis
Differential Diagnosis of Knee Pain:
1.
Internal derangement (Meniscus, Ligament, etc)
2.
Fracture
3.
Patellofemoral Pain Syndrome
4.
Cartilage loss (osteoarthritis or synovitis)
5.
Bursitis, tendonitis, friction syndromes (ITB, medial plica)
6.
Synovitis, inflammatory arthritidies
7.
Gout, pseudogout
8.
Referred pain from hip, spine, etc.
History:
Any trauma or acute injury?
Yes:
Mechanism of injury?
Direct blow?
Foot planted?
Decelerating?
Twisting?
Hyperextension? (consider
ACL)
Hear or feel “pop”? (noises are non-specific)
Injury stop play?
Bruise?
Swelling immediate (within 2 hours) or after
several hours (next day)?
Lock or give-way?
No:
Any new activities?
Increased volume?
Increased intensity?
Increased hills?
Increased weight-lifting?
Increased jumping?
Increased explosive movements (pylometrics)?
Pain:
Onset insidious or rapid?
Where does it hurt? Most?
Use one finger!
When does it hurt? Rest,
activity, up or down stairs?
Cinema sign?
Physical Exam of the Knee
1.
Patients must be comfortable and relaxed for exam
a. Inform patients what
you are doing and that goal is not to cause pain
b. Reassure that
testing will not hurt (and mean it!)
c. Avoid or skip tests
that cause pain. (I never do a
Patellar Grind Test.)
d. Test the uninjured
joint first--both for your comparison and to reassure patient.
e. Use an exam table
that solidly supports patient, neither narrow nor flimsy.
Any
quadriceps and/or hamstring tension will mask knee instability and invalidate
your exam.
2.
Look for concomitant injuries.
Any force significant enough to produce damage to one tissue will likely
damage others
3.
You must have a mental picture of the anatomy (some knees are chubby).
The exam is a deliberate process of considering each anatomic component
of the joint and evaluating it for pain and integrity.
4.
The knee exam is stepwise:
1. Survey visually
2. Check for effusion
3. Palpate structures
(use your MRI)
4. Stress:
a. Collateral ligaments
b. Cruciate ligaments
c. Menisci
A.
Survey Visually
1. Contusion.
Asymmetrical swelling, bruising, and abrasion
2. Bursitis.
Focal, extra-articular swelling and tenderness
a. Prepatellar -
kneeling
b. Superficial
Infrapatellar - kneeling
c. Pes Anserine - often
in the setting of Osteoarthritis
3. VMO atrophy?
4. “J” sign
5. Gait.
Some authors recommend “duck waddle” and squat as components of every
exam. These are effective for
quick, global screening of knee function (e.g. during preparticipation sports
physicals), but are not particularly helpful in the patient who presents with
knee injury.
B.
Check for Effusion
Effusion = fluid collected within the synovial
membrane of the knee joint.
Therefore, consider what is inside the synovial membrane.
Effusion implies injury to one of 3 structures:
Cruciate ligaments
Menisci
Articulating cartilage/bone
Effusion: Differential Diagnosis:
Intraarticular derangement (hemarthrosis)
Osteoarthritis
Gout
Pseudogout
Seronegative spondyloarthropathies (IBD,
psoriasis, Reiter’s)
Rheumatoid arthritis
(and other Connective Tissue Disorders)
Tumor
Infection
Large effusion:
“ballotable patella”
Small effusion:
milk the suprapatellar pouch and feel/watch for infrapatellar fluid
shift
C.
PALPATE STRUCTURES
Medial
1. Medial joint line
Þ
Fracture of tibial plataeu
(frequency of lateral > medial fx’s)
Medial compartment osteoarthritis
Medial meniscal tear
2.
Medial collateral ligament
Þ
MCL tear or strain
3.
Pes anserine bursa
Þ
Bursitis
4.
Medial plica (RARE!)
Þ
Medial plica syndrome
Anterior
1.
Superior-lateral aspect of patella
Þ
PFPS
2.
Prepatellar bursa
Þ
Bursitis
3.
Inferior pole of the patella
Þ
Patellar tendonitis, “jumper’s knee”
4.
Medial border of patella
Þ
Patellar subluxation or dislocation
5.
Tibial tubercle
Þ
Osgood-Schlatter disease
6.
Diffuse B/L knee pain & swelling
Not hot, red
Þ
OA in multiple compartments
Hot, red, tender
Þ
Inflammatory arthritis
(rheumatoid, crystalline)
Septic arthritis
Lateral
1. Lateral joint line
Þ
Fracture of tibial plateau
Lateral compartment Osteoarthritis
Lateral meniscal tear
2.
Lateral collateral ligament
Þ
LCL tear or strain
3.
Lateral femoral condyle
Þ
ITB friction syndrome
POSTERIOR
Popliteal pain and pressure is usually due to effusion and can be
associated with any injury to structures within the synovial capsule.
D.
PROVOCATIVE TESTS
1.
Patellar grind test (Clarke’s sign)
Not always useful or necessary.
Can be falsely positive and is quite painful in patients with PFPS.
2.
Stress the collateral ligaments
Apply valgus and varus stress to the knee at 30°
flexion and at 0°
flexion. Look and feel for joint
laxity and feel the character of end points.
Test can be falsely positive in the setting of osteoarthritis (or another
cause of cartilage wear).
Grade 1 Strain = Tenderness at ligament with NO
laxity at 30°
Grade 2 Strain = Minimal 30°
laxity (NO 0°
laxity). Solid end-point.
Grade 3 Strain = Significant 30°
laxity (minimal to no 0°
laxity). Soft, mushy or no
end-point. Joint space opens > 1
cm. Grade 3 = complete collateral
ligament rupture.
“Grade
4 Strain” = Positive 0°
laxity! Must consider ACL and/or
PCL tear.
3.
Stress the cruciate ligaments
a. ACL (least to
most sensitive)
1. Anterior drawer
test
?
Patient supine
and relaxed. Hamstring muscles
relaxed.
?
Hips flexed,
knees at 90°.
?
Examiner sits on
patient’s feet with thumbs on tibial plateau.
2.
Lachman’s test
?
Patient supine
(not watching) and relaxed (let the hips externally rotate).
Knee at 20°
-30°
flexion(can place over examiner’s knee).
?
Feel for
increased laxity and soft, mushy end-point.
Changes can be subtle; asymmetric laxity >1 cm can be associated with
complete ACL tear.
?
The Lachman’s
test done on the sideline is often the most accurate due to the lack of
reflexive muscle spasm and hemarthrosis
that occurs within hours after the injury.
3. Pivot shift test
?
Fully extend knee
and internally rotate foot.
?
Flex knee while
applying a valgus stress.
?
Watch & feel for
clunk of tibia on femur.
?
More specific but
difficult to perform when patient guarding.
The composite of all 3 tests is the most
sensitive and specific for detecting ACL injury.
In one review: 74% sensitivity, 95% specificity.
(Ref 1)
B. PCL
1. Posterior Drawer
?
Exactly like
anterior drawer testing.
2. Sag sign
?
In position for
drawer testing, note the “sag” of the tibia posterior (watch for loss of the
anterior skin-ridge associated with the tibial plateau!)
?
Sag corrects with
extension of knee against resistance.
4.
Stress the Menisci
The medial meniscus is injured far more commonly
than the lateral. The lateral
meniscus is attached only to the popliteus muscle and is more mobile than the
medial meniscus, which is attached to both the capsule and the medial collateral
ligament. Recall “unhappy triad”.
McMurray Test:
?
Patient supine
and relaxed.
?
Pain may prohibit
flexion of the knee. If considering
meniscal tear based on history and joint line tenderness, try internal/external
rotation of extended knee first.
?
Start with knee
fully flexed; stress applied during extension of the knee.
?
Hands are at the
heel and joint line. Evaluate for
pain and palpable click.
?
Medial meniscus:
Varus stress with internal rotation of foot.
RECALL that the toes and the knees point in different directions.
?
Lateral meniscus:
Valgus stress with external rotation of the foot.
?
McMurray’s test
can result in entrapment of posterior horn tears and result in palpable clunk.
While unable to entrap anterior horn tears (hence, no clunk), the test
usually exacerbates joint line pain.
?
Classically, a
palpable clunk at the joint line was considered positive.
Now, a reproduction of the patient’s pain during testing is also
considered positive.
(Ref. 2)
A.
IMAGING
Who needs an X-ray?
·
2 Decision Rules:
·
In 3/2005, Dr
Mark Ebell (AFP Editor) sited a 2001 study and said the Ottawa Knee Rule “should
not be used in pediatric populations.”
(Ref. 3)
However, a 2003 multicenter study of the
Obtain radiograph if:
1.
Younger than 12yo
or older than 50yo.
2.
Unable to take 4
steps in E.D./office.
Obtain radiograph if:
1.
Age 55 or older.
2.
Tenderness at
fibula head.
3.
Isolated
tenderness at patella.
4.
Inability to flex
knee to 90 degrees.
5.
Inability to bear
weight for 4 steps BOTH immediately and in office.
“The
Robb G, Reid D, Arroll B, et al. General
Practitioner diagnosis and management of acute knee injuries: summary of an
evidence-based guideline. Journal
of the
Causes and Treatment of Knee Pain
A.
Osteoarthritis
?
3 Compartments in
the knee. Medial compartment is
most susceptible to age-related degeneration
?
3 of 6 clinical
characteristics:
1.
Greater the 50 years old
2.
Morning stiffness less than 30 min
3.
Crepitis
4.
Bony tenderness
5.
Bony enlargement
6.
No warmth
?
4 radiographic
finding of OA:
1.
Asymmetrical joint space narrowing
2.
Bone sclerosis
3.
Osteophytes, “spurring”
4.
Subchondral cysts
History:
?
Achy pain for
weeks or months
?
Onset of symptoms
may be precipitated by minor injury or usual use of joint
?
Increased pain
after activity
?
Increased
stiffness after rest (<30min in morning)
Exam:
?
Anterior/Posterior pain with decreased ROM suggests effusion.
?
MTP at joint
line.
?
Positive crepitus
and palpable spurring.
?
Weight-bearing
radiographs are positive for changes listed above.
Treatment:
?
Relative rest
(weight loss, cane)
?
Moist heat
?
Activity
modification (decreased weight bearing)
?
Muscle
strengthening
?
Glucosamine
sulfate
?
Tylenol / NSAIDs
?
Steroid or
synvisc joint injection
?
Ice for flares
?
Quadricep
strengthening
B. Bursitis
?
Pes Anserine
bursitis is usually due to OA
?
Prepatellar
bursitis is usually due to trauma, “housemaid’s knee”
?
Differential
includes infection (Septic Bursitis) and Gout
Exam:
?
Focal tenderness
and swelling at bursa. Otherwise,
knee exam is normal.
?
Radiographs
normal except for soft tissue swelling.
?
Completely
extra-articular!
Treatment:
?
Aspirate!
?
If crystals,
treat underlying gout (can consider instilling steroid through needle).
?
If infection,
needs drainage and antibiotics.
?
If clear
(trauma), may consider steroid injection.
?
Approximately 95%
of cases (noninfectious) will resolve with patience, heat or ice, rest, and
NSAIDs.
E. Synovitis
?
Synovitis is
NOT a result of trauma, overuse
injury, joint degeneration or structural injury.
Synovitis: Differential Diagnosis:
?
Infectious
?
Reactive
arthritis (Reiter’s, IBD)
?
Rheumatoid
arthritis
?
Vasculitis
?
Lupus
?
Crystalline
arthritis
History:
?
Joint pain,
warmth, swelling, pain with weight-bearing
?
No trauma,
activity change, etc.
Exam:
?
Aspirate!
(see Table)
?
Joint tenderness,
warmth, swelling, and erythema
Treatment:
?
Depends upon
cause of synovitis.
C.
Septic Joint
?
Medical emergency
?
Gonococcal vs.
non-gonococcal (which is usually Staph. aureus)
History:
?
Joint pain,
warmth, swelling, pain with weight-bearing
Exam:
?
Aspirate!
?
Joint tenderness,
warmth, swelling, and erythema
?
Swelling and
tenderness extend beyond joint
?
Fever and high
WBC’s may be present
Treatment:
?
Gonococcal: IV
antibiotics
?
Non-gonococcal:
Emergent surgical or open drainage,
parenteral antibiotics
D.
Crystalline Arthropathy (Gout vs. Pseudogout)
?
Gout arthopathy
is akin to bad fudge
?
Normal serum
urate approximately 3 to 8
?
Acute attack can
occur in anyone with urate >6 (So, some attacks occur in pt’s with normal
urate!)
?
Most with
hyperuricemia never have attack.
(So, high urate does not make a diagnosis of Gout.)
?
Acute flares are
separated by asymptomatic intercritical periods.
?
Recurrence is the
rule as is insidious joint destruction.
?
Tophi appear
after 12 years on average.
History:
?
Joint pain,
warmth, swelling, pain with weight-bearing
?
Escalation of
pain to maximum within hours
?
Acute attacks in
single joint account for 80% of cases (Therefore, 20% of cases involve 2 or more
joints—don’t get fooled.)
Exam:
?
Aspirate!
?
Joint tenderness,
warmth, swelling, and erythema
?
Swelling and
tenderness extend beyond joint
?
Fever and high
WBC’s may be present
Treatment:
?
NSAIDs
?
Steroid injection
?
Colchicine
?
Allopurinol
F. Medial Collateral Ligament Strain or Tear
?
Often injured by
valgus stress in dirt-biking and in football (“clipping”)
?
Recall, 1st
degree strain has tenderness but no instability while 3rd degree
strain (MCL rupture) has gross instability at 30°
flexion.
History
?
Valgus stress to
knee
Exam
?
Tenderness along
MCL +/- instability
Treatment:
?
Rest
?
Ice
?
Protection with
hinged brace
?
Physical Therapy
G. Lateral Collateral Ligament Strain
?
Less common than
MCL injuries
History:
?
Varus stress to
knee
?
Usually occurs in
setting of large trauma to knee (MVA, etc.)
Exam:
?
Tenderness at LCL
+/- instability
Treatment:
?
Surgical repair
of severe LCL tears
?
Rest
?
Ice
?
Hinged brace
?
Physical Therapy
H. Anterior Cruciate Ligament Injury
?
Common in trauma,
but 70% of ACL injuries are NONCONTACT
?
Usually a
cutting, deceleration or hyper-extension movement
?
Hemarthosis
yields rapid swelling (severe within 2 hours)
?
female:male ratio
is 4-6:1 (Injuries increased dramatically after Title IX)
History:
?
Often feel “pop”
and immediate pain
?
Acute injury that
stops play
?
Describes
instability, laxity, “giving-out”
Exam:
?
Effusion (about
70% of patients presenting with hemarthosis)
?
Anterior drawer
sign
?
Lachman’s test
?
Pivot shift
?
SKIP THE MRI!
In one study, the overall accuracy of MRI for detecting ACL tear was 91%
while the accuracy of clinical diagnosis was 90%!!!!
(Ref 6)
Treatment:
?
Surgical
reconstruction recommended for adolescents and young adults.
?
Non-surgical
“conservative” therapy often leads to meniscal injuries, unstable knee
(“giving-out”) and accelerated osteoarthritis—particularly in patients active in
jumping or cutting sports.
?
Elderly with
sedentary, low-impact life-style may consider non-operative management
(physical therapy, bracing)
?
Physical Therapy
for proprioceptive training is well supported by evidence for both
post-reconstruction and ACL-deficient knees.
(Ref 5)
NOTE: In a recent trial of conservative
treatment of ACL ruptures, almost two thirds of those patients primarily treated
conservatively eventually returned for operative reconstruction.
(Ref 7)
I. Posterior Cruciate Ligament Injury
?
Less commonly
injured than ACL
?
Usually injured
in the setting of a large trauma to knee with posterior blow to the
tibia(consider concomitant injuries!).
Common settings: MVA (tibia hits dashboard), contact sports.
?
Less commonly
occurs with forced hyperextension
History:
?
Rarely feel tear
or “pop”
?
Instead report
vague discomfort and unsteadiness
Exam:
?
Posterior drawer
test is the most sensitive (90%) and specific (99%) for PCL injury
(Ref 8)
Treatment:
?
Non-operative vs
surgical reconstruction? “Clear
indications for surgical reconstruction of PCL do not exist.”
(Ref 8)
J. Meniscal Tear
?
Menisci (2)
cushion and stabilize the knee
?
Meniscal tear is
the most common knee injury
?
Usually, injury
is due to twisting on a planted foot
?
Nourished by
synovial fluid, so free bodies remain viable.
But, tears often do not heal due to poor vascular supply.
?
Medial injuries
are 10 times more common than lateral injuries because medial meniscus is less
mobile (attached to MCL).
History:
?
Often, no
twisting injury is recalled (Getting out of car-- esp. in elderly)
?
May feel pop or
tear
?
Pain at medial or
lateral joint line
?
Effusion develops
over hours (often reaches maximum on day 2)
?
May “lock”
Exam:
?
Effusion
?
Tender joint line
?
McMurray test
positive
?
Try treatment before MRI!
Overall accuracy of MRI for detecting meniscal tears was 68% for medial
and 86% for lateral tears. Accuracy
of clinical exam was 64% for mensical tears.
(Ref 6)
Treatment:
?
One third to one
half will “heal” to become asymptomatic without surgery
?
Meniscectomy may
accelerate osteoarthritis
?
Rest: first no
weight, then no twisting (consider crutches and then brace)
?
Ice
?
Crutches
?
MAYBE Physical
Therapy (quadriceps strengthening).
BUT:
?
“Physiotherapy
should not be routinely advocated following menisectomy.”
(Ref 5)
?
Swimming
?
Surgery if true
locking or persistent pain
MRI: Before ordering a test, question whether
the result of the test will change your management.
Greater than 1/3 of meniscal tears will become asymptomatic without
intervention. In addition, surgical
repair of tears occurring in the setting of DJD does not significantly improve
symptoms. Finally, MRI is positive
for meniscal tear in up to 1/3 of asymptomatic individuals!
(Ref 9)
K. Iliotibial Band Friction Syndrome (ITBFS)
?
Overuse injury
?
Exclusive to
athletes - usually runners
History
?
Complain of
lateral knee pain that develops during runs
Exam:
?
Tight ITB
?
Tender at lateral
femoral condyle
?
Often have
palpable (not audible) click or snap
at ITB with knee flexion
Treatment:
?
Reduced mileage
?
ITB/tensor fascia
lata stretching
?
Steroid injection
?
Ice, NSAIDs,
Physical Therapy
NOTE:
A recent systematic review was attempted to assess interventions for
ITBFS. They found only 4 RCT’s on
treatment: NSAIDs, deep friction massage, phonophoresis and corticosteroid
injection. They concluded that
“there seems limited evidence to suggest that the conservative treatments that
have been studied offer any significant benefit in the management of ITBFS.”
(Ref 10)
L. Patellofemoral Pain Syndrome (PFPS)
?
Anterior knee
pain
?
Classically
described in untrained females (high Q-angle) who are starting new activity
(untrained VMO)
?
However, can
occur in very trained athletes due to muscle imbalance
?
Only 20% of PFPS
is associated with chondromalacia patella (the pathologic term for cartilage
degeneration on the underside of the patellar facets)
History:
?
Similar to OA,
but PFPS is the most common cause of pain in individuals under 45 years old
?
Increased Q angle
?
Increased pain
with activity
?
Increased
stiffness with rest (cinema sign)
Exam:
?
VMO atrophy
?
Positive J-sign
?
Tender
superior-lateral pole of patella
?
Positive patellar
grind test (if done)
Treatment
?
Activity
modification
?
VMO strengthening
?
Hamstring,
quadricep and ITB stretching
?
Taping and
bracing has unproven benefit (Ref 11)
?
Ice, NSAIDs
?
Orthotics
?
Surgery (smooth
patella, release lateral retinaculum)
?
Self-limited?????
M. Tendonitis
?
Patellar
Tendinitis (“Jumper’s Knee“) much more common than Quadricep Tendinitis
?
Weight lifters
and jumping/sprinting athletes--pylometric (a.k.a. explosive) activities.
History:
?
Pain with
activity
?
Decreased knee
extension
?
Stiffness with
rest
Exam:
?
Tenderness at
tendon--usually at its insertion at the patella
?
Pain reproduced
by resisted extension of the knee
Treatment:
?
Rest
?
Heat/Ice
?
NSAIDs
?
Stretching
?
Rehab/strengthening of tendon
?
NEVER steroid
injection
N. Medial Plica Syndrome
?
Plica are folds
of the synovial membrane at the knee
?
Medial plica may
become locally inflamed or irritated by trauma or overuse
History:
·
Usually have
vague complaints of medial joint pain with activity (but may report acute onset
of surprisingly severe pain)
Exam:
?
Locally tender at
media plica (palpate a mobile nodularity noted at the anterior, medial joint
space)
?
Tender at medial
femoral condyle
?
Palpable snap at
50 – 70 degrees of knee flexion
Treatment:
?
Rest, Ice
?
Physical Therapy
(patella mobilization, stretching)
?
Surgery very
rarely
O.
Avascular Necrosis
?
Think of AN at
the femoral head, humeral head, and talus.
But, AN can occur in many joints.
?
Idiopathic, or
?
Secondary to:
steroid use
gout
alcohol
History:
?
Stiffness
(particularly in morning), limping
?
Vague,
poorly-localized pain
?
Gradual onset of
pain and swelling
?
Recurrent
effusion
?
> 50 yo
Exam:
?
May be focally
tender
?
Diagnosis made
with X-ray radiograph
Treatment:
?
Rest and NSAIDs
?
< 50% require
joint replacement
Osteochondritis Dissecans
=
idiopathic avascular necrosis in young adults and
children (<50yo). See
history and exam above.
P.
Osgood-Schlatter Disease
?
Classified as
osteochondritis or aseptic necrosis
?
History of
trauma vs. history of
pylometric activities
?
Occurs while
upper tibial epiphyseal plate is open (ages 8-15)
?
Males : Females =
3:1
History
?
Pain increases
with activity, stair climbing, squatting
Exam:
?
Local tenderness
?
Swelling
?
X-ray usually
normal; may see variable separation at physis
Treatment:
?
Rest
?
Stretching
?
NSAIDs, Ice after
activity
?
“Cho-Pat” or
patellar tendon brace?
Q.
Fractures of the Knee
?
Always secondary
to trauma
1.
Tibial plateau (common)
?
Usually traumatic
force to lateral knee such as a valgus stress
Treatment:
Displaced fractures require ORIF of depressed
plateau fragment
2.
Patella
?
Direct trauma
Table: Synovial Fluid Findings in
Joint Disease
References
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Evaluation of acute knee pain in primary care.
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Calmbach WL, Hutchens M.
Evaluation of patients presenting with knee pain.
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3.
Ebell MH. Evaluating the
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Bulloch B, Neto G, Plint A, Lim R, et al.
Validation of the Ottawa Knee Rule in children: A multicenter study.
Ann Emerg Med. 2003;
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5.
Robb G, Reid D, Arroll B, et al. General Practitioner diagnosis and
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Thomas S, Pullagura M, Robinson E, et al. The value of magnetic resonance
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Knee Surgery,
Sports Traumatology, Arthroscopy
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7.
Strehl A, Eggli S. The value
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8.
Brown JR, Trojian TH.
Anterior and posterior cruciate ligament injuries.
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9.
Boden SD, Davis DO, Dina TS, et al.
A prospective and blinded investigation of MRI of the knee.
Abnormal findings in asymptomatic individuals.
Clin Orthop
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10. Ellis
R, Hing W, Reid D. Iliotibial band
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11. D’hondt NE, Struijs PA, Kerkoffs GM, et al. “Orthotic devises for treating patellofemoral pain syndrome (Cochrane Review) CDSR 2002; CD 002267