AVascular necrosis of the femoral head is caused by loss of blood supply to the femoral head. It has traumatic causes like hip dislocation or fractures, and non-traumatic causes like steroid use, alcoholism, radiation. Clinically it presents with groin pain and reduced range of motion. It is classified by stages of collapse from intact bone to arthritis. Treatment depends on stage, but includes non-weight bearing, core decompression, bone grafts, osteotomies, hemiarthroplasty or total hip arthroplasty for late stages. The goal is to delay collapse, relieve symptoms, and restore hip function.

1. AVASCULAR NECROSIS OF
FEMORAL HEAD
DR. Gaurav Singh
Central Institute of orthopaedics
VMMC & Safdarjung Hospital

2. BLOOD SUPPLY
H.V.CROCK (1965)
• 1. Extracapsular arterial ring of the femoral
neck which is formed by the medial and lateral
circumflex arteries which are in turn branches
of deep femoral artery.
• 2. Ascending cervical branches from the
extracapsular ring which further give rise to
metaphyseal and epiphyseal branches. They
are placed on medial, lateral, anterior and
posterior aspect of femoral neck.
• 3. Artery of round ligament which is a branch
of obturator artery.

3. Treuta (1957) – Variation in the blood supply with
age

4. Definition
• Avascular necrosis of the femoral head also known as aseptic necrosis
or ischemic necrosis is defined as a clinical entity which causes a
circumscribed area of bone necrosis that results due to loss of blood
supply to the femoral head

5. Etilology
• Multifactorial disease and the causes of avascular necrosis of head of
the femur are broadly classified into two categories, they are
traumatic and non-traumatic.
Traumatic
#Neck of femur Dislocation of hip joint
15% to 50%.
Prevalence of osteonecrosis,
depending on fracture
type, time until reduction,
and accuracy
of reduction.
10%-25%.
If more than 12hours to the
time since reduction,
prevalence doubles.

7. Non traumatic
Steroid use – 30% of prevalence out of all AVN.
10%-20% of steroid use develop AVN.
Renal transplantation, SLE and psoriasis.
Bilateral.
Per day dose, duration and TOTAL CUMULATIVE DOSE.
A meta-analysis of twenty-two studies of steroid- associated osteonecrosis
revealed a 4.6-fold increase in the rate of osteonecrosis for every 10 mg/ day
increase in mean daily dose.

8. Excessive alcohol - how much is excessive…???
• An intake of >400mL of alcohol per week increased the relative risk of
osteonecrosis 9.8-fold.
• Patterson et al.(1964) and Jones et al.(1968) reported 17% and Zinn
et al(1971) 16%.
• Various hypothesis suggested for pathogenesis – subchondral
osteoporosis and mircofractures, fat embolus obstructing end arteries
and changes in the coagulational properties leading to further
thromboembolic phenomenon.

9.  Radiation induced
Hemoglobinopathies
Gastro-renal diseases
Lipid storage disorders – Gaucher’s
Caisson disease

10. Clinical features
• Antalgic gait
• Tenderness over the groin region.
• Reduced range of motion of the affected hip joint mainly internal. Range
of motion may be associated with pain. Clicking sound at hip. Pain on
internal rotation and click is suggestive of already collapsed head.
• Axis deviation – Demonstrated when the patient is asked to fully flex the
hip joint the axis of the limb will be directed towards the axial of the same
side instead in being in line with the mid-clavicular line.
• Patient may be having deformities such as flexion and adduction
deformities.
• Shortening may be present.

11. Classification
• Ficat and Arlet classification (1964) –
Stage 0 – In the normal hip in bilateral involvement
Stage 1 – Symptoms - present
Raiological - absent

12. Stage 2 – Increased density
Cysts
Sclerosis
Intact sphericity

13. • Stage 3 – Deformed head without
the acetabular involvement.
Stage 4 - Arthritic changes

14. Association Research Circulation Osseous (ARCO)
system - 1993
• Same as Ficat and arlet.
• Stage 1,2 and 3 are further divided into 3 substages
Minimum <15%
Moderate 15% - 30%
Extensive >30%
• Crescent sign in stage 3

15. UNIVERSITY OF
PENNSYLVANIA
CLASSIFICATION
1995

16. MRI
• Can pick the lesion earlier then x-rays can do.
• Better sensitivity and specificity.
• Decreased or irregular intensity in both
T1 and T2.
• T2 - Double line sign.

17. Medical Management
• Non – weight bearing --- Prevents collapse of the femoral head.
Only a precautionary measure.
• NSAID’s – for pain relief.
• Lipid lowering drugs – In STEROID INDUCED AVN.
Prevents the divertion of conversion
osteoblasts into adipocytes.
Pritchett JW (2001) in a clinical study reported that, AVN in only 3 (1%)
of 284 patients who were taking high-dose corticosteroids along with
statins drugs in contrast to prevalence of 3-20% reported for patients
receiving high-dose corticosteroids without statins.

18. • Bisphosponates –
• Inhibit the resorptive action of mature osteoclasts.
• increase the level of apoptosis of osteoclasts in vitro and may
decrease apoptosis of osteoblasts and osteocytes
 Retard the progression of femoral head collapse and reduce the
incidence of total hip replacement .
Improve clinical function and pain.

19. Surgical
• Head preserving – all procedures are time buying.
necrosis
reduces vascularity odema
increases pressure
• Head replacement

20. Core decompression
• By Ficat and it was an accidental discovery.
• Principle is comparable to “Compartment syndrome”
• Intraosseous pressure reduced promotes new bone formation.
• Conventional method is by trephine (subtrochanteric fractures and
penetration into the joint), studies has shown good results with
multiple small drillings with 3-4mm.
• Has been proven only in the pre-collapse stage.
• Retards the progression to collapse.

21. Adjuvant to core decompression
• BMA - MSC’s conversion to osteoblasts.
• Bone graft
Non – vascularised
 Structural
support
 Promotes growth
of new blood
vessels
Vascularised
 Intact blood vessel so faster
and better.
 Vascular surgery and
microsurgery.
 Eg – iliac crest, fibula..

22. Muscle pedicle bone graft –
Eg -
TFL
Quadratus femoris
Sartorius

23. Osteotomies
• Principle - to change the weight bearing portion of the femoral head.
• Works best when involvenment is <30% or necrotic angle of less than
200
Transtrochanteric rotational osteotomies - by Wagner and Zeiler
performe osteotomy with a maximum of 180° of rotation of the
necrotic segment.

24. • Varus or valgus osteotomy with flexion or extension

25. TANTALUM ROD
• The new tantalum rod is made up of a biocompatible material with a
porosity of 75%. It has been used to replace the necrotic bone
segment to prevent collapse in Steinberg stage I-III femoral AVN. The
presence of pores allows rapid bony ingrowth.
• The disadvantage of the tantalum rod is that if the disease progresses,
the tip of tantalum rod in the collapsed femoral head may protrude
into the acetabulum.
• Moreover, there will be technical difficulty in removal of the tantalum
rod in case of complications because of its strong bio-integration to
the surrounding bone.

26. Hemi - replacement
• Hemiarthroplasty is an option in young patients with either an
extensive pre-collapse lesion or a post- collapse lesion without
acetabular involvement.
The damaged cartilage on the femoral head is removed
Revision to a subsequent total hip arthroplasty is not complicated

27. THA – “Ultimate surgery”
Indications
• Osteonecrosis of the femoral head and associated advanced
secondary degenerative arthritis with severe damage of the femoral
head articular cartilage and loss of acetabular cartilage and
• An older or low-demand patient with extensive involvement or
collapse of the femoral head as well as sufficient symptoms to justify
total hip arthroplasty.
Several authors have demonstrated that total hip arthroplasty provides
more complete and reliable pain relief compared to bipolar
arthroplasty.