Download The Joint Exam in Ehlers

The Joint Exam in Ehlers-Danlos
Syndrome
Dr. Elizabeth Russell M.D.
Div. Rheumatology
Medical College of Wisconsin
A continuum:
Normal range of motion
Laxity
Subluxation (voluntary)
Subluxation (involuntary)
Dislocation
Laxity is relative!
Many populations have considerably
greater joint laxity as “normal”
(ex. Egypt, India)
Laxity
Laxity is voluntary or involuntary
joint range of motion exceeding
accepted normal range.
Instability is laxity that results in
greater joint dysfunction (example:
subluxation) and is involuntary.
Laxity
What causes it?
Normal constraints to range of
motion of any joint are
multifactorial:
Bone contours
Capsule
Intraarticular meniscus
Ligaments
Muscles
Adjacent soft tissues
Gravity
Abnormal bone end contours
•Can be secondary to injury
•Can be secondary to congenital
malformation
Capsule abnormality
•Can be torn (trauma)
•Can have altered physical properties
(example Hypermobile EDS where
tissue structure allows greater
stretching in a tissue without inherent
recoil)
Intraarticular meniscus
Normally found in knee,
temporomandibular joints
Helps control excursion of bone ends,
distribute forces
Can be torn or undergo degeneration
Muscle abnormality
• Bulk of overlying muscle affects joint
motion allowed by spatial interference
• Tone of adjacent muscles helps hold bone
ends together: more tone = less likelihood
bone end excursion (example: subluxations
in EDS during sleep when muscle tone
decreased)
Adjacent soft tissue abnormality
Compliance of adjacent tissues
affects range of motion (example:
increased overlying collagen
deposition in scleroderma decreases
joint range of motion; converse in
forms of EDS where skin thin,
decreased fat in subdermis)
Effect of gravity!
Gravitational force exerted on
weight-bearing joints helps hold
joints together assuming alignment is
normal (example: this may be an
issue in EDS when involuntary
subluxations occur in bed at night in
lower extremity joints)
Assessment of Laxity/Instability:
Best Assessed by Physical Exam
Radiology largely a static
assessment;
Newer technologies will be dynamic
Assessment by Other Modalities:
•Ultrasound may be used for large
joint instability assessment; less
useful for small joints
•X-ray useful to assess end-point
excursion of bone ends
•MRI just starting to be utilized as
dynamic study
The Physical Exam
•Inspection: alignment important
•Palpation: can differentiate osseous
vs. soft tissue prominence
•Range of motion: key to assessing
laxity
•Instability testing
Laxity testing:
Can be done within only 1 plane or
assessed in multiple planes, keeping
normal physiologic range of motion
in mind (example: the shoulder needs
to tested in multiple planes given the
usual large ROM)
Special Techniques:
“Click Sign” for capsular laxity:
examiner distracts bones and
reopposes in effort to assess capsule
tightness. Look for dimpling of
overlying skin during distraction and
a “click” felt when articular surfaces
abut again
Video
Evaluation of joint laxity in a patient
with hypermobile EDS
What to do with exam data
Beighton scores: estimation of joint
laxity at 5 sites (thumb,
finger,elbow,knee,spine)
Hypermobility defined as values
greater than 6
Useful as a standard for comparison
Presence of small joint
hypermobility only
More associated with vascular form
of Ehlers-Danlos Syndrome
Presence of generalized
hypermobility
• Seen in most forms of Ehlers-Danlos
Syndrome (not dermatosparaxis) but most
noticeably in arthrochalasia and
hypermobile forms
Presence of large joint
hypermobility only
Most characteristic of hypermobile
form of Ehlers-Danlos Syndrome
In summary:
•Approaching assessment of hypermobility
should take into consideration various
factors that influence laxity
•Physical exam should look for excess
range of motion as well as for evidence of
subluxation
•Beighton scoring provides some
quantification of laxity