SI Joint

Question 1

anatomy and clinical implications

Answer 1

anatomical structures do not function in isolation
sacrum, pelvis, spine and connections to appendicular skeleton are functionally interrelated
“the most contentious issue in SIJ research is mobility of the joint”

Question 2

historical perspective

Answer 2

SIGJs mobile only during pregnancy
SIJ shown to be mobile in both men and women
nutation and counternutation (flexion/extension)
X-ray analysis during supine to stand showed 0.5-0.7 cm motion (nutation - relative between endpoints)

Question 3

SI joint

-from the 1930s through 1980s, SIJ fell out of favor as scientifice explanation for…

Answer 3

LBP

Question 4

SIJ joint current view (still controversial)

Answer 4

primary function
-stable support to upper body
limited mobility, but sacral movement involves SIJ, directly influences discs and higher lumbar joints
nutation/counternutation of sacrum affects L5/S1
finite element models estimate a 1 cm leg length discrepancy results in 5-fold increase in SIJ loads

Question 5

SIJ mobility - motion studies

Answer 5

6 mm translation during nutation
5 mm translation (rods in iliac bones)
2 degrees movement between double and single leg stance (surgical rods in ilia and sacrum)
CONCLUSION: current studies support limited motion of about 2 degrees in all 3 planes

Question 6

correlation between clinical tests and relative SIJ hypomobility (radiographic method)

Answer 6

no correlation

Question 7

SIJ mobility assessment

• intrarater reliability
• interrater reliability

Answer 7

intra
-kappa: -0.005 to 0.073
inter
-kappa: -0.032 to 0.081

Question 8

SIG mobility assment validity

-false positive rate

Answer 8

16%

Question 9

SIJ radiostereometric recorded motion

Answer 9

0.2 to 0.6 degrees (too small to detect manually)

Question 10

why do we use the Gillet Test if we can’t use it to reliably determine SIJ motion?

Answer 10

balance challenge - SIJ “locks” for stability

movement of the external pelvis relative to the hips gives the illusion that the SIJ are repositioned

Question 11

standing flexion test

-utility

Answer 11

represents a non-specific change in lumbo-pelvic-hip mechanics, not specific to SIJ

Question 12

what do we do with this information and these tests

Answer 12

go back to regional interdependence
we can gain information about movement strategies, patterns and control from these tests
-we are movement specialists
avoid making pathoanatomic diagnoses from these test findings - they do not give us underlying mechanisms for pain
can still be used to provide some information that guides treatment