This document discusses avascular necrosis of the femoral head. It begins by defining avascular necrosis as bone death associated with disrupted blood flow, often caused by corticosteroid use or alcoholism. It then covers the pathogenesis, classifications based on radiographic findings, diagnosis using MRI and CT scans, and various treatment approaches. For pre-collapse cases, core decompression and bone grafting are discussed. Total hip arthroplasty is the treatment for advanced collapse or cartilage damage. The document provides details on advantages and disadvantages of different surgical techniques.

1. AVASCULAR NECROSIS OF
THE
FEMORAL HEAD
Dr. Sanjay saini
2nd Year Junior Resident
Dept Of Orthopedics
S.M.S Medical college and Hospital Jaipur

2. DEFINATION
• Avascular necrosis is death of bone that may be associated with
circulatory disruption from various factors. Corticosteroid use
and excessive alcohol intake are associated with >80% of the
cases.
• These factors diminish femoral perfusion through mechanisms
including vascular endothelial damage and microvascular
thrombosis.
• It also induce intramedullary adipogenesis, which increases
intraosseous pressure leading to venous stasis and arterial
obstruction.

3. PATHOGENESIS
• Corticosteroids can decrease osteoblast production, increase
osteocyte apoptosis, and prolong the osteoclast lifespan.
• Clinicians should exercise a high level of suspicion in at-risk
patients (those who use corticosteroids consume excessive
alcohol, have sickle cell disease, etc.) in order to diagnose
osteonecrosis of the femoral head in its earliest stage.

4. CLASSIFICATION
Stage Description
I. Normal radiograph and abnormal MRI findings
II. No crescent sign, radiographic evidence of sclerosis, osteolysis, or
focal osteoporosis
III. Subchondral fracture, fracture in the necrotic portion, and/or
flattening of the femoral head on radiograph or CT scan
III A. Femoral head depression of <2 mm
III B. Femoral head depression of >2 mm
IV. Evidence of osteoarthritis, joint space narrowing, and degenerative
acetabular change

6. DIAGNOSIS
• The diagnosis of ONFH typically involves radiographs and
magnetic resonance imaging (MRI). MRI is up to 100% sensitive
for this diagnosis.
• The presence of subchondral fracture suggests disease
progression and may help to define the treatment course.
Computed tomography (CT) may be superior to MRI in detecting
subchondral fractures.
• Successful treatment depends on accurate staging. There is no
consensus regarding the best classification system since many
have demonstrated limited interobserver and intra observer
reliability

7. TREATMENT
Operative:
1. Precollapse:
• Core decompression
• Multiple small-diameter drilling
• Adjunctive bone-grafting
• Cell-based therapy
• Non vascularized bone-grafting
• Vascularized bone-grafting
• Tantalum rod
• Rotational osteotomy
• Angular osteotomy
2. Postcollapse:
• Total hip arthroplasty
Non Operative:
• Observation
• Weight-bearing restriction
• Bisphosphonates
• Anticoagulants
• Vasodilators
• Acetylsalicylic acid
• Extracorporeal shockwave
therapy
• Pulsed electromagnetic
fields
• Hyperbaric oxygen

8. NONOPERATIVE THERAPY
• Avascular narcosis typically follows a progressive course, with a majority of
untreated lesions leading to collapse.
• Nonsurgical treatment modalities have generally been ineffective at halting
progression. They are not appropriate in early stages when attempting to
preserve the native joint, except for rarely encountered, small-sized, medially
located lesions.
• Recent studies have evaluated the efficacy of pharmacological therapy including
bisphosphonates anticoagulants, vasodilators, acetylsalicylic acid, and lipid
lowering agents. Biophysical modalities including extracorporeal shockwave
therapy, pulsed electromagnetic fields and hyperbaric oxygen have also been
investigated.
• However, studies have been small-scale, single-center, and of low-level
evidence, often with inconclusive results. Therefore, these modalities remain
experimental.

9. OPERATIVE TREATMENT
 Core Decompression
• For precollapse Avascular narcosis, core decompression (CD)
procedures can be performed in an attempt to preserve the
femoral head.
• They have been used for >50 years and have been shown to
outperform nonoperative management of precollapse lesions.
• There appears to be a consensus in the literature that CD is more
effective than nonoperative management on the basis of a few
older small-scale randomized studies.
• CD is typically performed under fluoroscopic guidance based on
the lesion location depicted by MRI.

10. CONTD…..
 The use of MRI for real-time 3-dimensional CD guidance is
technically feasible, safe, and accurate.
 Some authors have reported using multiple small-diameter (3 to
8-mm) drilling rather than a large single core, as they may be less
invasive and decrease the risk of fractures.
 Attempts have been made to enhance the results of CD with bone
grafts, synthetic bone substitutes, bone morphogenetic proteins,
tantalum rods, or adjunctive cells.

11. A trocar is introduced into the necrotic lesion using light mallet blows under
fluoroscopic guidance.

12. ADVANTAGES
 Ease of availability
 Potential for multilineal differentiation (osteoblasts,
chondrocytes, lipocytes, tenocytes, etc.)
 No risk of malignant transformation
 Free of ethical issues
 Can be combined with osteoconductive materials (e.g., various
bone grafts).
 Need for additional surgical procedure
 Potential for harvest site morbidity

13. DISADVANTAGES
 Increased cost and surgical time
 Need for additional equipment
 Not osteoconductive
 Does not provide structural support
 Inherent differences in sample composition among individual
patients
 The number of osteogenic progenitor cells that are being
implanted is unknown at the time of the procedure

14. ADVANTAGES AND DISADVANTAGES
OF VARIOUS VASCULARIZED BONE-
GRAFTING TECHNIQUES
Technique Advantages Disadvantages
1. Lateral femoral
circumflex vessel-
pedicled iliac bone
• Minimal donor-site morbidity
• Corticocancellous, unicortical, or
bicortical bone
• Large amounts of cancellous bone
can be harvested as additional
graft material
• Long, large-diameter pedicle
facilitates blood flow
• No need for microsurgery
• Potential damage to
lateral femoral
cutaneous and
ilioinguinal nerves

15. Technique Advantages Disadvantages
2.Greater trochanter
flap
• No need for
microsurgery
• May not provide as much
support as fibular grafts
3. Free vascularized
fibular graft
• Endosteal and
periosteal blood supply
• Dual blood supply
allows for different
osteotomies
• Cortical bone provides
good structural support
• No cancellous bone
• Flexor hallucis longus
contracture
• Claw toe deformity
• Peroneal nerve injury
Gait alterations Ankle
instability
4. Sartorius muscle
-pedicled iliac bone
• No need for
microsurgery
• May not provide as much
support as fibular grafts
5. Gluteus medius
-pedicled greater
trochanter flap
• No need for
microsurgery
• May affect hip mobility
May not provide as much
support as fibular grafts

16. TOTAL HIP ARTHROPLASTY
 THA has been the treatment of choice for symptomatic advanced
stage femoral head collapse, particularly when secondary
acetabular changes are noted.
 Suitable candidates for THAs include patients who have large
lesions with or without collapse or those who have cartilage
delamination without apparent collapse.
 THA has been shown to yield excellent results in multiple
studies with outcomes comparable with those for patients who
have other diagnoses

19. 