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Imaging adult hip pain
Department of Imaging and Interventional Oncology Prince of Wales Hospital
James F Griffith
What’s hip in hip imaging
º Early onset OA º Hip dysplasia º Femoroacetabular impingement (FAI)
º Non-FAI impingement syndromes of hip
º Abductor tendon problems (greater trochanteric pain syn.)
Acetabular lines
Acetabulum ‘vinegar bowl’ [Lt]
Sourcil ‘eyebrow’ [Fr]
Hip dysplasia - too shallow
Acetabulum should cover ~ 80% of the femoral head
Mild Moderate Severe
Hip dysplasia - too deep
º Floor of acetabular fossa extends beyond ilioischial line
normal profunda
Centre-edge (CE) angle
º Normal centre-edge (CE) angle 25 - 400 º Abnormal < 200 or > 400
Beltran LS et al AJR 2012
Acetabular index
º Normal acetabular index 0 -10 degrees º Negative value indicates profunda
Acetabular retroversion
Three radiographic signs of acetabular retroversion
head-neck junction ‘pistol-grip deformity’
Proximal femoral morphology
Osseous bump Os supra-acetabulare
º These radiographic abnormalities are reliable
Femoroacetabular Impingement (FAI)
º Not as common in the East º Leads to premature labral injury & premature OA º Cam-type, pincher-type & mixed type
Cam-type
α=39° α=64°
Cam-type
Normal alpha angle < 550
Cam-type
Most severe cam-type deformity at anterosuperior plane → renewed interest in radial hip imaging (should use 600 as cut-off)
Sutter R et al Radiology 2012
Insert Movie 1
Normal Protrusio
Pincher (protrusio) global overcoverage
Pincher (retroversion) Focal overcoverage
Femoral torsion
↓ femoral torsion Impingement in internal rotation
↑ femoral torsion Impingement in external rotation
Sutter R et al Radiology 2012
Femoral torsion
Normal femoral torsion = 12- 150
Sutter R et al Radiology 2012
FAI – controversy
º Very high no. of asymptomatic radiographic deformity º Only small number → osteoarthritis
Hartofilakidis G et al JBJS 2011
º Level of activity clearly important
Hartofilakidas G et al JBJS 2011 deBruin F et al Eur Radiol 2013
º Considerable inherent variability in imaging assessment
º FAI is a clinical diagnosis º “Acetabular ±femoral morphological tendency to FAI”
Pelvic tilt
>Pelvic tilt ↑ acetabular coverage → ↑ likelihood of impingement
Sutter R et al AJR 2013
Morphology – so what ??
º Very little can be done º Operative success questionable º Helps to explain symptoms º Potential for prevention
Shallow acetabulum Deep acetabulum
Retroverted acetabulum Proximal femoral dysplasia
Hip pain, Labral injury Premature OA
Labral tear description
Frayed
Full thickness
Degenerate
Partial thickness
Labral tear description
Frayed Degenerate
Labral tear description
Partial thickness Full thickness
Labral / paralabral cyst
• Anterior • Superior • Posterior
6
12
3
9
Reverse clock-face
Labral tear localisation
Labral tears
55% tears occur just between 3 – 12 o’clock 95% occur between 3-12 o’clock & beyond
3 12
Sublabral sulcus in 20%
At anteroinferior & posteroinferior aspects
Iliopsoas impingement
º Isolated anterior labral tear at 3 o’ clock º Considered due to iliopsoas impingement
Blankenbaker DG et al AJR 2012
Articular cartilage
Hip cartilage very thin (3.5mm - 4mm in total)
Articular cartilage
Cartilage delamination & ligamentum teres tear
Hip Traction
Llopis E et al AJR 2008
No traction Traction
Arthrography – Yes or No
º Direct arthrography more sensitive º Loose effect of seeing hip joint effusion º Moderate post-arthropathy pain is common,
delayed & lasts~2 days º Non-invasive → invasive investigation
º Time consuming, ↑ cost, ↓ unit productivity
3.0T or 1.5T Cardiac coil (6 element SENSE)
T2 SPIR obl cor
PD obl cor
PD FS obl ax
PD FS obl sag
± T2 FS (whole pelvis)
±PD axial (whole pelvis)
Ischiofemoral impingement
º Impingement of quadratus femoris m.
º More common in women º Deep-seated buttock pain
º Often bilateral, but only one side symptomatic º Can respond to steroid/ long acting LA injection
Ischiofemoral impingement
º Ischiofemoral distance º 13.5mm ±5mm in patients vs 23 ±8mm controls
Torriani M et al AJR 2009
Ischiofemoral impingement
Insert Movie 2
Gr. trochanter - facets
Anterior facet
Lateral facet
Gr. trochanter - facets
Posterosuperior & Posterior facets
Gr. trochanter - facets
Gr. trochanter – tendon insertions
Glut. minimus Glut medius
Gr. trochanter – tendon insertions
Gr. trochanter – bursa
Glut. Min. bursa Glut med bursa Trochanteric
Abductor tendons
Gluteus minimus Gluteus medius
Abductor tendon tears
Gluteus minimus tear
Peritendinitis
Abductor tendon tears
Gluteus minimus avulsion
Abductor tendinosis & tears
º Very high % are bilateral & asymptomatic º Tears much more likely to be symptom indicative
Blankenbaker DG et al Skel Radiol 2008
45 volunteers (38 years)… 3T MRI
º 69% had labral tears º 13% has labral / paralabral cysts º 24% had chondral defects º 11% acetabular bone oedema º 22% has fibrocystic change in head/neck region º 20% had osseous bumps º 16% had subchondral cysts º Overall, 73% has some abnormality
Register B et al Amer Jour Sports Med 2013
Hip imaging is hip!
º Things might look a bit messy
º Plenty to be happy about!
Thank you!