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!