Sports Medicine: Just the Facts

RADIOGRAPHIC LINES AND ANGLES IN SPORTS MEDICINE 613

• Disruption: Fracture of posterior column of acetabu-
  lum.

TEARDROP
•Vertical tear drop shaped line, medial to femoral head.

• Cortical border of quadrangular plate.
  •Normal: Teardrop shape


• Disruption: Fracture or penetration through acetabu-
  lum into pelvis.


• Femoral head >5–8 mm lateral teardrop: Lateral dis-
  placement of femoral head from osteophyte or intra-
  articular loose body.

PERKIN’SVERTICALLINE
•Vertical line drawn through upper outer rim of acetab-
ulum.

HILGENREINER’SLINE

• Horizontal line drawn between inferior parts of the
  ilium.


• The femoral head ossification center should lie in the
  distal medial quadrant formed by the Hilgenreiner’s
  and Perkin’s lines.

SHENTON’SLINE
•Traces the arc of the obturator foramen and the med-
ical femoral neck.

• Disrupted in dislocation of the hip.


• May not appear intact in normal children until age 1.

ACETABULARINDEX(HILGENREINER’SANGLE)

• Line drawn along roof of acetabulum; intersecting
  with Hilgenreiner’s line.

AGE GIRLS BOYS

Birth < 36 °< 30 °

6 months < 28 °< 25 °

1 year <25°< 24 °

7 years <19°< 18 °

• Angles greater than above at risk for progressive dys-
  plasia.

EPIPHYSEALANGLE

• Line along proximal femoral epiphysis intersecting
  with Hilgenreiner’s line.


• Normal: <25°
  •Developmental coxa vara 40–70°.

WIBERG’SCENTEREDGEANGLE(CE ANGLE)
•Formed by two lines originating from center of
femoral head:

• One perpendicular to a line connecting the centers
  of the two femoral heads, drawn superiorly into the
  baseline of the acetabulum.


• One connecting the center of the femoral head with
  the superior femoral lip.


• Decreased in dysplasia of the acetabulum

AGE (YEARS) LOWEST NORMAL CE ANGLE VALUE

5–8 19 °

9–12 12–25°

13–20 26–30°

KLINE’SLINE

• Line drawn along the superior femoral neck.


• Normal: Symmetrical R and L


• If the line transects less of the femoral physis on one
  side, suggests slipped capital femoral epiphysis.

KNEE

Q ANGLE

• Anterior superior iliac spine (ASIS) to center of
  patella and tibial spine to center of patella.


• Normal <10–15°male; <15–20°female

INSALLRAT I O

• Lateral X-ray with knee flexed 30°.


• Ratio of length of patella to length of patellar tendon.


• Normal =1:1


• 0.8 or less Patella alta


• 1.2 or more Patella baja

SULCUSANGLE

• On merchant view.


• Line across lowest part of intracondylar sulcus to
  highest points on medial and lateral condyles.


• Normal: 126–150°


• Larger angles associated with patellar subluxation/
  dislocation.

CONGRUENCEANGLE

• On merchant view.


• Line from apex of sulcus angle to lowest point of
  patellar articular ridge and a line that bisects the
  sulcus angle.
  •Normal: − 6 °(male); − 10 °(female)


• Above 15°abnormal and associated with patellar sub-
  luxation/dislocation.

LATERALPATELLOFEMORALANGLE

• On merchant view.


• Line drawn down the lateral surface of the patella and
  line drawn along the medial and lateral femoral
  condyles.