Initial Evaluation and
Treatment of Knee Pain
in Adults
Jose Yasul, MD
April 29, 2009
Goals
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Make a decision and start treatment
Knee / Shoulder anatomy
Common pain patterns
Frequently encountered causes
Specific examination skills
Imaging
Labs
Differential diagnosis
Disclosure Slide
No relevant financial relationship exists to
potential commercial bias
Musculoskeletal Numbers
• Back 23%
• Knee 19%
• Shoulder 16%
Urwin M, Symmons D, Alison T, et al. Estimating the burden of musculoskeletal disorders in the
community: the comparative prevalence of symptoms at different anatomical sites, and the relation to
social deprivation. Ann Rheum Dis. 1998;57(11):649-655.
Knee Anatomy
• Bones
• Ligaments
• Menisci
History
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Time Course
Mechanism of injury
Pain characteristics
Mechanical symptoms
Effusion
Medical History
Acute Onset (Questions I ask)
• Date of injury
• Mechanism
• Able to walk or continue activity immediately
after injury
• Able to walk or bear weight since injury
• Effusion / bruising
• Mechanical symptoms
• 1st injury?
• Prior lower extremity injuries
Focused Physical Exam
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Inspection and palpation
Range of motion
Ligaments
Menisci
Patellofemoral assessment
Gait
Inspection and palpation / ROM
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Erythema, swelling, bruising, discoloration
Musculature
Pain, warmth, effusion
Point tenderness
Range of motion
Cruciate ligaments
• ACL
>Anterior drawer
>Lachman’s
>Pivot Shift
• PCL
>Posterior sag sign
>Posterior drawer test
Collateral ligaments
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MCL – Valgus stress
LCL – Varus stress
Compare to uninjured side
0 and 30 degrees of flexion
Menisci
• Joint line tenderness
• McMurray’s test
>Lateral meniscus – IR tibia + valgus stress
>Medial meniscus – ER tibia + varus stress
• Ege's test – May be the most sensitive
Imaging (X-rays)
• Bilateral AP Weight bearing
• Lateral
• Merchant’s view
Knee Fractures
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Patella fractures
Femoral condyle fractures
Tibial eminence fractures
Tibial tubercle fractures
Tibial plateau fractures
Quadriceps Injuries
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Quadriceps contusion
Quadriceps tendon sprain / rupture
Quadriceps muscle partial tear
Acute hamstring injuries tend to be more
proximal
• Acute calf injuries tend to be more distal
ACL
• Non-contact deceleration
• Plant and sharp turn – Anterior
displacement of tibia causes sprain or
rupture of ACL
• “Pop” felt followed by pain causing patient
to cease activity with swelling within 2 hrs
ACL
• Acutely moderate to
severe joint effusion
• Guarding and
hemearthrosis limits
testing in the acute phase
• Lachman test
• X-ray – tibial spine
avulsion
• MRI
MCL & LCL
• MCL more common than LCL
• Results from Valgus and varus stress
respectively
• Tenderness at respective joint line
• Valgus/varus stress at 0 & 30º reproduce
pain
• (+) endpoint grade I/II sprain
• (-) endpoint grade III sprain
Meniscal tear
• Sudden twisting injury or a prolonged
degenerative process
• Recurrent locking with squatting / twisting
• Tender joint line
• Quad atrophy
• McMurray testing / Ege’s testing
• MRI
Septic arthritis
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More common in immune compromised
Abrupt onset of pain
Warm, swollen, and exquisitely tender
MINIMAL motion causes INTENSE pain
Arthrocentesis
-WBC > 50,000/mm3
- Gram stain – Staph, Strep, Gonorrhea
• Blood – Elevated WBC, ESR, CRP
Make a Decision - DDx
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Knee contusion
Fracture
Muscle / tendon strain or rupture
Ligament strain or rupture
Meniscal injury
Infection
Exacerbation of chronic knee pain
Treatment goals
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Stabilize knee
Prevent further injury
Regain full function
Cause no harm
Treatments
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Reassurance
Limit activity / RICE
Braces and immobilizers
Crutches and canes (weight bearing status)
Home exercise program
Pain meds (Do not prevent further injury)
Follow up
Further imaging
Consultation / Referrals / admission
Chronic Onset (Questions I ask)
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How long?
What were you doing when pain first noticed
Prior injuries
Pain all the time or come and go
Swelling
Mechanical symptoms
What makes it better / worse (Theatre sign)
Treatments? (Rehab, bracing, meds)
Physical Examination
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Inspection and palpation
Range of motion
Ligaments
Menisci
Patellofemoral assessment
Feet & Shoes
Patellofemoral assessment
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Patient supine and knee in extension
Effusion in suprapatellar pouch
Tracking of patella
Crepitus
VMO tone
Patella apprehension test
Patellar grind
Feet & Shoes
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Pes planus
Posterior tibia tendon dysfunction
Treadwear
Solid sole
Imaging
• Adults 3 views
>AP
>Lateral
>Merchant’s or Sunrise
(Note: Teens, add notch or tunnel view )
Labs
• ? Of septic arthritis
>Blood – CBC-d, ESR, CRP
>Joint fluid
-cell count with differential
-glucose & protein
-bacterial culture
• Simple joint effusion
• Hemearthrosis
• Fat globules
Differential Diagnosis
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Patellofemoral pain syndrome
Medial plica syndrome
Pes anserine bursitis
Trauma – ligament sprains or meniscal tear
Inflammatory arthropathy
Septic arthritis
Older adults
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Osteoarthritis
Crystal induced inflammatory arthropathy
Gout, pseudogout
Popliteal cyst (Baker’s cyst)
Patellofemoral syndrome
(chondromalacia)
• The most common diagnosis in outpatients
presenting with knee pain
• Anterior pain - mild to moderate severity
• “Theater sign”
• Poorly localized “Circle sign”
• “Knee giving way”
• A final common pathway
Osteoarthritis
• Aggravated by weight bearing and relieved
by rest
• No systemic symptoms, morning stiffness
• Episodes of acute synovitis
• PE reveals decreased ROM, crepitus, mild
joint effusion, possibly palpable osteophytes
Osteoarthritis
• X-rays – Wt bearing
AP, lateral, Merchant
• Joint space narrowing
• Subchondral bony
sclerosis
• Cystic changes
• osteophytes
Crystal induced inflammatory
arthropathy
• Gout – Sodium urate crystals precipitate
and cause inflammatory response
• Pseudogout – Calcium pyrophosphate
• PE – Red, warm, swollen, tender
• Arthrocentesis
WBC – 2,000 to 75,000 per mm3
Protein – high (>32g/dL)
Glucose – 75% of serum
Gout Crystals
Pseudogout – Calcium
pyrophosphate
• CPPD crystals in the
fluid
• rhomboid or rodshaped, weakly
positively birefringent
crystals on polarized
light microscopy of
synovial fluid
Medial plica syndrome
• Frequently overlooked
source of medial knee pain
• Redundant joint synovium
inflamed with repetitive
overuse
• Tender, mobile nodularity
medial aspect of knee just
anterior to the joint line
• Medial knee pain
• Worse with repetitive
flexion and extension
Pes anserine bursitis
• Medial knee pain
• Worse with repetitive
flexion and extension
• Exam
>No effusion
>tenderness just post.
& distal to med jt line
>Pain reproduced by
valgus stress or
resisted knee flexion
Popliteal cyst (Baker’s cyst)
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Mild to moderate pain in popliteal area
The most common synovial cyst
Usually a response to preceding trauma
Posteromedial aspect at the level of the
gastrocnemiosemimembranous bursa
• Palpable fullness posteromedially
• McMurray test may be positive
Popliteal cyst (Baker’s cyst)
Definitive diagnosis of a
popliteal cyst may be
made with
arthrography,
ultrasonography, CT
scanning, or, less
commonly, MRI
Make a Decision - DDx
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Patellofemoral pain syndrome
Osteoarthritis
Crystal induced inflammatory arthropathy
Gout, pseudogout
Trauma – ligament sprains or meniscal tear
Medial plica syndrome
Pes anserine bursitis
Septic arthritis
Popliteal cyst (Baker’s cyst)
Treatments
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Reassurance
Limit activity
Braces and immobilizers
Crutches and canes (weight bearing status)
Home exercise program
Pain meds (Do not prevent further injury)
Steroids (Oral or injectable)
Follow up
Further imaging
Consultation / Referrals / admission
The role of the physician is to
entertain the patient while
Nature takes its course.
Voltaire