neck of femur anatomy

1. Anatomy and classification neck
femur in young adult
Dr.Rajesh Kumar Rajnish
Dept. of Orthopaedics,
UCMS & GTB hospital, Delhi

2. Introduction
• Fractures of hip have been described as an
orthopaedic epidemic
• Estimated global incidence-1.66 million
fractures(1990).
• Expected to increase to 6.26 million fractures
by 2050.
• Approx. 50% of these-intracapsular fractures.

3. Hip joint
• Ball-and-socket joint
composed of head of
femur and acetabulum

4. Anatomy
Proximal femur
The outline of the proximal
end of the femur is
characterised by almost
spherical head, slightly
flattened neck and two
trochanters with
communicating
intertrochanteric ridge

5. • Physeal closure age 16yrs
• Neck-shaft angle
130°-135°
<Coxa vera
> Coxa valga

6. Anteversion (Medial femoral
torsion)
• Angle subtended by femoral
neck to the transcondylar
axis of the knee joint.
15°- 25°

7. Calcar Femorale
• Dense vertical palte of bone
from Posteromedial femoral
shaft under LT to GT
• Reinforcing posterinferior
femoral neck

8. Trabecular patterns
• Principal Compressive
Group
• Principal Tensile Group
• Greater Trochanteric
Group
• Secondary Compressive
Group
• Secondary Tensile
Group
• Ward's Triangle

9. Blood supply
Crock described three major groups of
vessels
• Extracapsular arterial ring
• Ascending cervical branches of arterial
ring
• Artery of ligamentum teres

10. • Formed at base of femoral neck at level of
capsular attachment
• Posteriorly – branch of medial circumflex
femoral artery
• Anteriorly – ring is completed by branches of
lateral circumflex femoral artery
• Minor contributions Superior and inferior
gluteal arteries
Extracapsular ring

11. Medial circumflex femoral artery
It is a branch of
• profunda femoral artery
• femoral artery (rarely)
• Participates in formation of extracapsular ring
• Major contributor in extracapsular ring

13. Medial circumflex femoral artery
Gives of various branches
– Medial ascending cervical arteries (inferior
retinacular, medial metaphyseal)
– Posterior ascending cervical arteries
– Arterial branches to superior gluteal artery
– Branches to greater trochanter

14. Lateral ascending cervical artery
– Terminal branch
– Gives off metaphyseal branches to neck &
continues as lateral epiphyseal artery, a prominent
vessel, for femoral head
– Provides most of blood supply to femoral head in
children 3 to 10 years of age

16. Lateral circumflex femoral artery
It is a branch of
• Profunda femoral artery
• Femoral artery (rarely)
• Participates in formation of extracapsular ring
• Gives anterior ascending cervical arteries to
neck and femoral head

18. Ascending cervical arteries
• Also known as retinacular arteries (Within
the capsule), described initially by Weitbrecht
• Derived from extracapsular arterial ring
• Enters capsule at base of neck
• Subsynovial course
• Supplies metaphysis and epiphysis

19. • Ascend on surface of femoral neck in four
groups:
– Anterior
– Posterior
– Medial
– Lateral
• Lateral group most important- largest
contributor to femoral head. If damaged More
chances of AVN

20. Subsynovial intra-articular arterial ring
• At the articular margin of femoral head
• Formed by vessels that penetrate the head (epiphyseal
arteries)
• Lateral epiphyseal vessels supplying lateral weight-
bearing portion most important
• Joined by vessels from ligamentum teres.

22. Artery of ligamentum teres
• Branch of
Obturator artery or Medial circumflex femoral
artery
• Gives blood supply to a small area of head of
the femur
• Contribute little blood supply to femoral head
until age 8 and then only about 20% as an
adult .
• Not sufficient to maintain blood supply of
feoral head.

23. Blood supply of metaphysis
• Extracapsular arterial ring
• Anastomoses with intramedullary branches of
the superior nutrient artery system
• Branches of the ascending cervical arteries
• Subsynovial intra-articular ring (descending
metaphyseal arteries)

24. Significance Blood supply of metaphysis
• Excellent vascular supply to
metaphysis explains the absence of
avascular changes in the femoral
neck as opposed to the head.

25. CLASSIFICATION
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ANATOMICAL LOCATION
• Subcapital
• Transcervical
• Basicervical (base of the neck fracture)

27. Classification
Pauwels Classification
• Based on the angle of the fracture line across
the femoral neck.
• Relates to biomechanical stability
• Predictive of more fixation failure and
nonunion with increasing angle
• More vertical fracture has more shear force

28. Classification
• Pauwels
– Angle describes vertical shear vector

29. Garden Classification
• Based on the degree of displacement of the
fracture noted on pre-reduction antero-
posterior x-rays in relation to trabecular line in
femoral head to those in acetabulum
• Most frequently used
• Four groups

30. Garden Classification
I Valgus impacted or
incomplete
II Complete
Non-displaced
III Complete
Partial displacement
IV Complete
Full displacement

31. Garden Classification
• Poor interobserver and intraobserver reliability.
• Outcome of undispalced and displaced fractures
are independent of grade assinged.
• Modified to:
– Non-displaced
• Garden I (valgus impacted)
• Garden II (non-displaced)
– Displaced
• Garden III and IV

32. Orthopaedic Trauma Association
(OTA) Classification
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• Alphanumeric fracture classification
• Femoral neck fractures are designated type 31B
• 31 is the proximal femur group and B the femoral
neck subgroup
• Its complexity limits its usefulness in routine
clinical practice
• Mainly used for research purposes
• Neither useful in selecting treatment option nor in
predicting outcome.

33. • B1 group fracture is undisplaced to minimally
displaced subcapital fracture
• B2 group includes transcervical fractures
through the middle or base of the neck
• B3 group includes all displaced non-impacted
subcapital fractures

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35. Singh Index
• Based on the pattern of proximal femoral
trabecular line
• A method of estimating degree of osteoporosis
• Six separate categories

36. Grade VI:
• All normal trabecular groups are visible
• Upper end of femur seems to be completely occupied by
cancellous bone
Grade V:
• Principal tensile & principal compressive trabeculae is
accentuated
• Ward's triangle appears prominent
Grade IV:
• Principal tensile trabeculae are markedly reduced but can still
be traced from lateral cortex to upper part of the femoral neck

37. • Grade III:
• A break in the continuity of the principal
tensile trabeculae opposite the greater trochanter
• this grade indicates definite osteoporosis
Grade II:
• Only principal compressive trabeculae stand out
prominently
Grade I:
• principal compressive trabeculae are markedly
reduced in number and are no longer prominent

39. Limitations
• Little practical value.
• Poor interobserver and intraobserver leves of
agreement
• Does not correlate with bone density as
measured.

40. Imaging and other Diagnostic Studies
Radiography
•Preferred initial
modality in evaluating
femoral neck fractures
•AP and Lateral views
•Lateral view gives idea
regarding dispalcement
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41. Limitations
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• Spiral fractures are difficult to assess on a
single view.
• Comminution is not easily demonstrated
• Some stress fractures are simply not visible on
plain images.

42. COMPUTED TOMOGRAPHY
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• Because of its superior resolution, cross-sectional
capabilities, and amenability to image
reconstruction in the coronal and saggittal planes,
• Useful for assessing fracture comminution
preoperatively and in determining the extent of
union (or lack there of) postoperatively.

43. MRI
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• In cases of doubtful diagnosis MRI may be useful
additional modality.
• Can also show soft tissue problems associated
with hip pain in absence of fracture.
Limitations
• Relative lack of widespread availability
• Its higher costs
• Exclusion of patients with cardiac pacemakers

44. Nuclear Medicine
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• In past technititium bone scan was used in
situations when plane radiography not able to
show fracture.
• Usually show positive result in fracture neck
femur.
• False negative results in osteopenic bone if
carried out within 48-72 hrs of injury.
• Sensitive but not specific
• CT scan is more accurate