3. ..
0 extracapsular arterieal ring at the base of the femoral neck;
- formed posteriorly by large branch of MFCA
- formed anteriorly by smaller branches of LFCA;
- superior & inferior gluteal artery have minor
contributions;
- ascending cervical branches
- these give rise to retinacular arteries;
- gives rise to subsynovial intra articular ring
- artery of ligamentum teres;
- derived from obturator or MFCA;
- inadequate to supply femoral head with displaced
fractures;
- forms the medial epiphyseal vessels;
- only small & variable amount of the femoral head is
nourished by artery of ligamentum teres;
4. ..
0 - epiphyseal blood supply:
- arises primarily from lateral epiphyseal vessels
that enter head posterosuperiorly;
- vessels from medial epiphyseal artery entering
thru ligamentum teres;
- epiphyseal arterial branches:
- arise as arteries of subsynovial intraarticular
ring;
- two groups of epiphyseal arteries: lateral &
inferior vessels;
- metaphyseal blood supply:
- arises from extracapsular arterial ring;
- arise from branches of ascending cervical
arteries, & subsynovial intra articular ring
5. Etiology and Risk Factors
0 Osteonecrosis can be associated with traumatic or
nontraumatic conditions
Traumatic Osteonecrosis-mechanical interruption of the circulation to the
femoral head.
1)displaced fracture of the femoral neck (15% to 50% )
2)Hip dislocation (10% to 25% )-dislocations of more than twelve hours in
duration being double that associated with dislocations that are reduced more
promptly
Nontraumatic Osteonecrosis
1) Corticosteroid intake-associationof osteonecrosis with corticosteroid
therapy in a number of respiratory and rheumatic conditions and in
patients who have undergone organ transplantation as well as on the
fact that patients with Cushing disease have a somewhat higher
prevalence of osteonecrosis. Higher doses, even for shorter duration,
present greater risks. Doses of corticosteroids of >20 mg/day appear
to be associated with a higher risk of osteonecrosis.
6. ..
2) Excessive alcohol use-intake OF >400 Ml of alcohol
per week increased the relative risk of
osteonecrosis 9.8-fold
3) Hemoglobinopathies including hemoglobin SS (sickle
cell disease), hemoglobin SC, and sickle
thalassemia (4% to 20% )
4) Caisson disease-Dysbaric osteonecrosis with deep
sea diving with poorly controlled decompression
5) Hypercoagulability -hereditary thrombophilia ,
impaired fibrinolysis , antiphospholipid
antibodies(anticardiolipin antibodies and lupus
anticoagulants), hyperlipidemia
8. Diagnosis
1) History -especially if the patient has one of the atraumatic conditions that are
associated with osteonecrosis
2) Symptom -deep pain in the groin
3) Physical examination-pain on internal rotation of the hip, a decreased range of
motion, an antalgic gait, and clicking in the hip when the necrotic fragment
has collapsed. Pain with internal rotation of the hip and a limited range of hip
motion are often signs that the femoral head has already collapsed.
4) Radiographic studies -anteroposterior and frog-leg lateral radiographs are
essential . Radiographic changes in the femoral head usually occur many
months after the onset of the disease and include cysts, sclerosis, or a
crescent sign. The crescent sign results from subchondral collapse of the
necrotic segment.
B) Magnetic resonance imaging has become the standard for diagnosing
osteonecrosis. It is 99% sensitive and specific. A single-density line on the
T1-weighted image demarcates the normal ischemic bone interface, and a
double-density line on the T2-weighted image represents the hypervascular
granulation tissue
C) Computed tomography scans
10. Classification and Staging
Ficat and Arlet originally developed a four-stage
classification system based on radiographic
changes and the functional exploration of bone,
which included intraosseous venography and
measurement of bone marrow pressure.
0Stage I Normal
0Stage II Sclerotic or cystic lesions
0Stage III Subchondral collapse
0Stage IV Osteoarthritis with decreased joint space
with articular collapse
11. University of Pennsylvania
system of classification0 University of Pennsylvania system of classification and staging
0 Stage 0 Normal or nondiagnostic radiograph, bone scan, and magnetic
resonance imaging
0 Stage I Normal radiograph; abnormal bone scan and/or magnetic
resonance imaging
0 A Mild (<15% of head affected)
0 B Moderate (15% to 30% of head affected)
0 C Severe (>30% of head affected)
0 Stage II Lucent and sclerotic changes in femoral head
0 A Mild (<15% of head affected)
0 B Moderate (15% to 30% of head affected)
0 C Severe (>30% of head affected)
12. ..
0 Stage III Subchondral collapse (crescent sign) without flattening
0 A Mild (<15% of articular surface)
0 B Moderate (15% to 30% of articular surface)
0 C Severe (>30% of articular surface)
0 Stage IV Flattening of femoral head
0 A Mild (<15% of surface and <2-mm depression)
0 B Moderate (15% to 30% of surface or 2 to 4-mm depression)
0 C Severe (>30% of surface or >4-mm depression)
0 Stage V Joint narrowing and/or acetabular changes
0 A Mild
0 B Moderate
0 C Severe
0 Stage VI Advanced degenerative changes
13. Treatment
The primary goals of treatment should be to relieve pain, to maintain a
congruent hip joint, and to delay the need for a total hip arthroplasty for
as long as possible
1) Core Decompression-currently is the most common procedure used to
treat the early stages of osteonecrosis of the femoral head. Originally,
core decompression was employed by Ficat and Arlet to obtain
histologic specimens to confirm that patients actually had osteonecrosis.
Since decompression of the femoral head allowed the intraosseous
pressure to return to normal, it was referred to as a core decompression
and thereby reduce the intraosseous pressure in the femoral head,
restore normal vascular flow, and subsequently alleviate the pain in the
hip.Core decompression can be performed alone or combined with
nonvascularized grafts (allograft bone or demineralized bone matrix) ,
vascularized bone grafts (fibula or iliac crest) , electrical stimulation.
The results of core decompression were substantially worse when there
had been collapse of the femoral head preoperatively
14. The fibular graft with the peroneal vessels is harvested from the
ipsilateral calf for insertion into the core in the femoral neck and head.
15. ..
0 The patients are usually placed on a fracture table. A
guide wire should be placed into the area of
osteonecrosis. It is critical that the starting hole for the
core decompression be made just proximal to the level
of the lesser trochanter to avoid the development of
stress fractures in the femur. A biopsy specimen should
be obtained whenever possible to provide definitive
confirmation of the diagnosis. Protective weight-bearing
with crutches is recommended for a minimum of six
weeks after the surgical procedure. Surgeons have
recommended combining core decompression with
nonvascularized or vascularized grafts to enhance bone
formation in the femoral head and to prevent fracture
through the proximal part of the femur.
16. ..
0 . The rationale for management of osteonecrosis of the femoral
head with a free vascularized fibular graft is based on five
principles:
0 (1) decompression of the femoral head,
0 (2) removal of the necrotic bone,
0 (3) replacement with fresh autogenous cancellous bone,
0 (4) support of the subchondral bone with a viable strong bone
strut, and
0 (5) revascularization and osteogenesis of the femoral head.
0 Most of the necrotic bone is removed and is replaced with
autogenous fresh cancellous bone from the greater trochanteric
area or fibula with its peroneal artery and two veins is inserted
into the core to within 3 to 5 mm of the subchondral area and is
stabilized with a 0.62-mm Kirschner wire
18. DISADVANTAGES
1) Extensive surgical procedure
2) Complications associated with the harvesting of
the fibula including motor weakness, subjective
discomfort in the ankle and other sites in the leg,
and sensory abnormalities in the lower limb.
So it is a reasonable option for patients under the age
of fifty without collapse of the femoral head
19. 2) Osteotomies based on the biomechanical effect of
removing the necrotic or collapsing segment of the
femoral head from the principal weight-bearing area of
the hip joint. This area is replaced with a segment of
articular cartilage of the femoral head that is
supported by healthy, viable bone . Two main types of
osteotomies have been utilized: transtrochanteric
rotational osteotomies and intertrochanteric varus or
valgus osteotomies (usually combined with flexion or
extension). Transtrochanteric rotational osteotomies
were first reported by Wagner and Zeiler in the 1960s.
A major concern about using an osteotomy as an
interim procedure is that it may be difficult to convert
the osteotomized hip to a total hip arthroplasty if
necessary.
20. ..
0The criteria for the selection of patients for
osteotomy include:
0(1) an age of less than forty-five years and a
painful hip;
0 (2) an early post-collapse or late pre-collapse
status of the hip, with no narrowing of the
joint space or acetabular involvement;
0 (3) a small-to-medium lesion
0 (4) no chronic use of high doses of
corticosteroids.
21. ..
3) Nonvascularized Bone-Grafting
The procedure provides decompression of the
osteonecrotic lesion, removal of the necrotic bone,
and structural support and scaffolding for repair and
remodeling of subchondral bone. Currently, three
distinct approaches can be used to introduce bone
graft into the femoral head; the cortical strut graft can
be introduced through
(1) a core tract,
(2) a window in the femoral neck (a "lightbulb"
procedure),
(3) a "trapdoor" that is made through the articular
cartilage in the femoral head.
22. ..
0 Cortical strut-grafting, a procedure popularized by
Phemister , Boettcher et al. , and Bonfiglio et al. This
technique involves the removal of an 8 to 10-mm-
diameter cylindrical core of bone from the femoral
head and neck. This core tract is then filled with
cortical strut grafts harvested from the ilium, fibula,
or tibia. Postoperatively, protected weight-bearing is
used for three to six months.
0 Another method of introducing bone graft is through a
window in the inferior aspect of the femoral neck,
and the necrotic bone is excavated from within the
femoral head , filling the defect of the femoral head
with cancellous bone graft .
23. ..
0 The term lightbulb procedure was introduced by
Rosenwasser et al. In this procedure, the cortical
window is lifted from the femoral head-neck junction .
Cancellous bone graft from the iliac crest is used to fill
the defect in the femoral head after complete
evacuation of the necrotic bone.
24. ..
Schematic diagram demonstrating the cortical window at the femoral
headneck junction. The defect within the femoral head can be filled with
autogenous bone graft or various bone-graftsubstitutes.
25. ..
0 Another approach to bone-grafting of the femoral head
is through a "trapdoor" that is made through the
articular cartilage of the femoral head.
Intraoperatively, the femoral head is dislocated and the
collapsed segment is exposed. An approximately 2-cm
flap is elevated from the chondral surface with use of
scalpels and osteotomes. The necrotic bone is then
removed from the femoral head with curets and burrs
until viable bone is reached. This void can then be
filled with various types of autogenous grafts or bone-
graft extenders. This procedure was first delineated in
detail by Meyers et al.
26. ..
4) Limited Femoral Resurfacing Arthroplasty
is a viable option in young patients with either an extensive
pre-collapse lesion or a post-collapse lesion without
acetabular involvement . This procedure offers several
advantages:
(1) the damaged cartilage on the femoral head is removed,
(2) femoral head and neck bone stock is preserved, and
(3) revision to a subsequent total hip arthroplasty is not
complicated
Potential candidates for limited resurfacing of the femoral head
include (1) young patients with no or minimal degeneration of
the acetabular cartilage presenting with either a crescent sign
or collapse of the femoral head and (2) young patients without
femoral head collapse but with extensive osteonecrotic
involvement of the femoral head ( femoral head involvement
of >50%).
28. ..
5) Total Hip Arthroplasty is the single treatment with the highest
likelihood of providing excellent early pain relief and a good
functional outcome.
The main indications for total hip arthroplasty are
(1) 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
(2) 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.
Contraindicated in (1) young patients with early-stage
osteonecrosis of the femoral head for whom treatment options
that save the femoral head are available, and (2) patients at
excessively high risk for complications of total hip arthroplasty
(alcoholic)
29. ..
0The underlying diagnosis associated with
osteonecrosis of the femoral head appears to
have an impact on implant durability (those
who used corticosteroids or abused ethanol or
systemic lupus erythematosus or an organ
transplant had worse prosthetic
durability).Many of these patients are young
and active or may have poor bone quality
secondary to chronic corticosteroid use,
ethanol abuse, or sickle cell disease
30. Increased risk for specific
complications in THR patients
0 Patients being managed with immunusuppression
(such as long-term corticosteroid therapy or post-
transplant regimens) may be at increased risk for
infection.
0 Higher risk for postoperative dislocation
31. Treatment Algorithm According to the University of Pennsylvania
System of Classification and Staging
0 I and II (Asymptomatic) Observation, pharmacological
treatment,possible core decompression ± bone-
grafting
0 IA, IB, IC, IIA, IIB, and IIC (Symptomatic) Core
decompression ± bone-grafting, vascularized graft
0 IC, IIC, IIIA, IIIB, IIIC, and IVA (Symptomatic) Bone-
grafting (vascularized or nonvascularized),
osteotomy,limited femoral head resurfacing, total hip
arthroplasty
0 IVB and IVC (Symptomatic) Limited femoral head
resurfacing, total hip arthroplasty
0 V and VI (Symptomatic) Total hip arthroplasty