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Popliteal (Baker’s) Cyst
Normal Anatomy
The popliteal fossa
is diamond shaped
with four borders,
formed by the
muscles of the
posterior
compartment of
the leg and thigh.
Normal Anatomy
• The popliteal fossa is
the main channel for
neurovascular
structures entering and
leaving the leg.
• The tibial nerve and
common fibular nerve
are the most superifical
structures and the
popliteal artery is the
deepest.
Normal Anatomy
The GastrocnemiusSemimembranosus Bursa:
Pathophysiology
• “A benign swelling of the
semimembranous bursa found
behind the knee joint”
O’Sullivan 2014.
• Knee joint effusion
communicates with posterior
bursa through a valvular
opening
• Valve allows movement in one
directions only – out of knee
• Fluid collects in the bursa
causing enlargement and
bursitis
• Often referred to as a popliteal
cyst
Mechanism of Injury
• Bakers’ cysts can be
form by virtually any
cause of joint swelling:
arthritis, rheumatoid
arthritis, joint effusion,
meniscal tears, joint
capsule herniation into
the popliteal region
Classification
• Lindgren and Rauschning Criteria:
• Grade 0, absence of swelling and pain, no limitation of
range of motion;
• Grade 1, light swelling and/or a sense of posterior
tension after intense activity, minimal limitation of
range of motion;
• Grade 2, swelling and pain after normal activity, range
of motion limitation less than 20°
• Grade 3, swelling and pain even when resting, range of
motion limitation more than 20°
Classification
• Primary: No communication
between the distension of the
bursa and the knee joint with no
associated knee derangement,
majority seen in children.
• Secondary: communicates freely
with the bursa and the knee joint.
Majority are secondary.
Associated Pathologies
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•
•
•
•
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Rheumatoid arthritis
Osteoarthritis
Gout
Meniscal injury.
DVT
Popliteal artery
aneurysm
Subjective
• Age: Adult (if symptomatic), (50+ are
more likely.)
• Local pain at back of knee
• Pain when extending knee
• Posterior knee tightness on walking or
activity
• Reports Knee giving way or locking
• Clicking of the knee
• Knee stiffness
• History of meniscal injury, ACL injury
OA or RA
• Rupture: intense knee/calf pain,
swelling and redness.
Objective
• Palpable mass/swelling
at the posterior knee
joint line.
• Reduced knee ROM
• Pain at back of knee
when squatting.
Special Tests
Fouchers’ sign:
Knee in full extension and in 90 degrees flexion.
Examiner places thumbs around anterior knee joint line
and fingers into the fossa posteriorly.
Mass may be palpated at extension and disappear on
flexion to 45 degrees, whereas other masses may stay
firm.
Further Investigation
• Ultrasound or MRI
• Ultrasound has been
found to be a reliable,
rapid, and highly sensitive
technique of diagnosis.
• 5-18% prevalence rate by
MRI
• 40-42% prevalence rate
by ultrasound.
• Useful for differential
diagnosis.
Management
• Dependent on the cause
• Surgical intervention may be required if intra
articular pathology co-exists
• Conservative intervention manages symptoms
only
Conservative - Management
• Swelling management
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Massage
Ice
NSAID’s
Rest
• For restricted ROM: Manual therapy such as joint
mobilisations and home exercise programme of
quadriceps and hamstring stretches.
• For reduced strength: isometric knee strengthening
exercises
• Avoid high impact activities: substitute swimming or
cycling.
Surgical - Management
• Cyst aspiration
• Cyst drainage and injection of corticosteroid
into the cyst space
• Arthroscopy: resection of the valvular
opening, debridement
http://www.youtube.com/watch?v=nCcQU3ajfQ