AVASCULAR NECROSIS OF THE
Avascular Necrosis (AVN) of the femoral head is a
pathological process that results from interruption of
the blood supply to the bone.
Also known as Osteonecrosis/ Osteochondritis
Dissecans/ Chandler’s Disease
First described by Munro in 1738.
In 1835 Curveilhier depicted femoral head
morphological changes secondary to interruption of
First large sample size report by Mankin in 1962.
!!Compromise of the already tenuous blood supply!!
10-25% of traumatic hip dislocations,
risk with duration.
Non displaced femoral neck fractures 10%.
Displaced femoral neck fractures 15-50%.
True incidence of atraumatic AVN unknown but 518% of THR’s performed in US are for AVN.
Men:Women = 4:1
OA in relatively young patients; mean age at
Atraumatic AVN is bilateral in 30-70% but typically
Mechanical interruption of blood supply in traumatic
Precise genesis of atraumatic AVN is unclear. It is
hypothesized that various etiological factors:
Compromise the blood supply of the subchondral
Direct toxic effect on cells, with cellular necrosis
and impaired remodeling potential of the
subchondral bone with eventual collapse.
Iatrogenic sec. to
High dose oral corticosteroid regimens have a
Quantifying amount of alcohol intake that increases
risk of AVN has been problematic.
A prospective study suggests patients consuming
400ml of alcohol per week were 9.8 times more
likely to develop AVN.
Exact mechanism of atraumatic AVN not clearly
Extraosseous vascular factor
I. Arterial factors
Intraosseous vascular factors
I. Arterial factors
II. Venous factors
EXTRAOSSEUS VASCULAR FACTORS
Femoral Head blood supply is an End-Organ
System with poor collateral development
Trauma to the hip may lead to contusion or
mechanical interruption to the Lateral Retinacular
Vessels (main blood supply of the femoral head &
INTRAOSSEUS VASCULAR FACTORS
Circulating microemboli that block the
microcirculation of the femoral head
In conditions like-
Fat emboli (hyperlipidemia associated with
Sickle Cell Disease
Nitrogen bubbles in Caisson Disease
INTRAOSSEUS VASCULAR FACTORS
Enlargement of intramedullary fat cells or fatloading osteocytes causes the cells to expand; this
may be the most significant factor l/t obstruction of
Reducing venous outflow & causing stasis
S/i Caisson disease & SCD
Ficat et al demonstrated increased bone marrow pressure in the
femoral necks of a large number of patients with avascular necrosis
of the femoral head (AVN).
Alcohol & Steroid
Hypertrophy of Fat cells
Gaucher cells & Inflammatory cells
Encroach on intraosseous capillaries
Direct toxic metabolic effect on
Trauma, Infection & Arthritis
Effusions within the Hip joint
Tamponade of the LEVs
Non specific signs and symptoms
Pain and limitation of
Mostly localized to groin area but may also manifest
in the ipsilateral buttock, knee or greater trochanter
Passive ROM limited and painful, esp. forced
Distinct limitation of passive abduction.
SLR against resistance provokes pain.
“Log-roll” may elicit pain consistent with active
Patients with chronic symptoms may have flexion
Various investigations depending upon the
A-P and frog-leg lateral (cross table lateral is less
Early changes not visible but, over time, a
predictable pattern of radiographic change
Steinberg ME. Diagnostic imaging and role of stage and lesion size in
determining outcome in osteonecrosis of the femoral head. Tech Orthop.
Radiolucencies and sclerosis
Bone resorption and new bone formation
Progressive microfractures, subchondral collapse
Degenerative joint disease
Complete collapse of head with arthritic changes
NECROTIC ANGLE OF KERBOUL
Necrotic angle >200 degrees
Less favorable outcomes with
certain head sparing
(Beltran et al)
Indispensable for Accurate Staging of AVN because images
Size of the lesion
Gross estimates of stage
Avascular necrosis of the femoral head: high-field-strength MR imaging with histologic correlation.Lang P, Jergesen HE, Moseley ME,
Block JE, Chafetz NI, Genant HK. Radiology. 1988 Nov; 169(2):517-24.
Can also show revascularization.
Objective evidence of tissue changes in response
to treatment, allowing sequential evaluation on
Understanding and treating osteonecrosis of the femoral head.Mont MA, Jones LC, Sotereanos DG, Amstutz HC, Hungerford DS.
Instr Course Lect. 2000; 49():169-85.
T1 weighted image:
Subchondral changes in
of head with single line
normal from ischemic
T2 weighted image:
High signal line inside
a low signal line
Useful only in separating late pre-collapse stage
from early collapse
Steinberg ME. Diagnostic imaging and role of stage and lesion size in determining outcome in osteonecrosis of the femoral head.
Tech Orthop. 2001;16:6–15
Technetium 99m diphosphonate imaging is also a
Khanuja HS, Mont MA, Etienne G, Hungerford DS. Treatment algorithm for osteonecrosis of the hip. Techn Orthop. 2001;16:80–9
Arlet and Ficat in 1960’s
described a 3 part
staging system. Later a
4th stage was added in
Relies solely on plain radiographs, which are unrevealing early on.
No measurement of lesion size or articular surface involvement.
Steinberg ME, Hayken GD, Steinberg DR. A quantitative system for staging avascular necrosis. J Bone Joint Surg Br. 1995;77:34-41.)
Sugano et al. The 2001 revised criteria for diagnosis, classification, and staging of idiopathic osteonecrosis of the femoral head. Journal
of Orthopaedic Science. September 2002, Volume 7, Issue 5, pp 601-605.
TRANSIENT OSTEOPOROSIS OF HIP (TOH)
No findings of bone infarction or repair, which are the hallmarks of
The pathologic picture is primarily one of marrow edema, hence also
referred to as Bone marrow edema syndrome (BMES) .
Clinically, pain is usually more sudden, severe.
In females, esp.during 3rd trimester of pregnancy
Dx can be made readily based on MRI in most cases.
TOH is usually self-limiting. Rx is protected weight bearing to prevent
A diffuse low signal intensity in the T1-weighted image and a high
intensity in the T2-weighted image
Preserve rather than Replacing Femoral Head &
Early Intervention has favorable impact on the
disease prognosis irrespective of the treatment
NON OPERATIVE TREATMENT
RESTRICTED WEIGHT BEARING:
Very few studies.
Cane or crutch ambulation.
Small pre-collapse lesions:
Take longer to become symptomatic
Rarely may resolve spontaneously.
A meta-analysis of RWB as a Rx modality; 21
studies in 819 hips:
Only 22.7% were satisfactory clinically
67% required hip arthroplasty or a salvage
Now universally agreed, it is not an appropriate
Review Core decompression versus nonoperative management for osteonecrosis of the hip.Mont MA, Carbone JJ, Fairbank AC,
Clin Orthop Relat Res. 1996 Mar; (324):169-78.
LIPID LOWERING AGENTS
Prithcett in a clinical study reported that, at a mean
of 7.5 yrs, only 1% of 284 patients taking
corticosteroids along with STATINS developed AVN
of femoral head in contrast to a prevalence of 320% in patients taking steroids alone.
Statin therapy decreases the risk of osteonecrosis in patients receiving steroids. Pritchett JW. Clin Orthop Relat Res.
2001 May; (386):173-8.
Glueck et al reported the use of Anabolic steroid
Stanozolol (6mg/day) in patients who had
hypofibrinolysis associated with a high level
plasminogen activator activity. All patients showed a
decrease of symptoms at one year following
Idiopathic osteonecrosis, hypofibrinolysis, high plasminogen activator inhibitor, high lipoprotein(a), and therapy with
Stanozolol.Glueck CJ, Freiberg R, Glueck HI, Tracy T, Stroop D, Wang Y. Am J Hematol. 1995 Apr; 48(4):213-20.
Meizer et al studied the use of prostacyclin
derivative Iloprost, in patients with osteonecrosis of
femoral head and bone marrow edema syndrome.
Among 17 patients with early stage AVN, all had
clinical and radiographic improvement at one year.
MRI-controlled analysis of 104 patients with painful bone marrow edema in different joint localizations treated with the prostacyclin
analogue iloprost. Meizer R et al. Wien Klin Wochenschr. 2005 Apr; 117(7-8):278-86.
Glueck et al used enoxaparin (60mg/day, 12
weeks) to treat patients of thrombophilic or
hypofibrinolytic disorders and early stages of AVN.
AT 2 yrs, 89% had not required surgery and were
still in Ficat stage 1 or 2. They suggested that Rx of
the underlying coag. Disorder may arrest or delay
progression of AVN if started early.
Enoxaparin prevents progression of stages I and II osteonecrosis of the hip.Glueck CJ, Freiberg RA, Sieve L, Wang P. Clin
Orthop Relat Res. 2005 Jun; (435):164-70.
Lai et al, in a study of patients with Steinberg Stage
2 or 3 osteonecrosis of the femoral head who were
either treated with alendronate (70mg/day for 25
weeks) or assigned to a control group. At a
minimum of 2 year follow up:
Only 2 of 29 hips in alendronate group had loss of
femoral head integrity compared with 19 of 25 hips
in control group (p<0.001)
1 hip in alendronate group and 16 hips in control
group underwent THR.
However doses required and duration of treatment
are yet to be clearly defined.
Also long term effect of these drugs, many of which
have extremely long half lives, on normal bone
homeostasis and turnover also merits caution.
The use of alendronate to prevent early collapse of the femoral head in patients with nontraumatic osteonecrosis. A randomized
clinical study. Lai KA, Shen WJ, Yang CY, Shao CJ, Hsu JT, Lin RM. J Bone Joint Surg Am. 2005 Oct; 87(10):2155-9.
EXTERNAL, BIOPHYSICAL, NON OPERATIVE
PULSED ELECTROMAGNETIC FIELD STIMULATION
Two fundamental mechanisms of action:
1. Important role in control of local inflammmation.
2. These favor repair activity and can potentiate the healing process by
stimulating neo-vascularization and new bone formation.
Biophysical stimulation with pulsed electromagnetic fields in osteonecrosis of the femoral head.Massari L, Fini M, Cadossi R,
Setti S, Traina GC. J Bone Joint Surg Am. 2006 Nov; 88 Suppl 3():56-60.
Radiographic progression in Ficat stage II . Hips treated with core
decompression (CD) plus pulsed electromagnet fields (PEMF) exhibit
33% less radiographic progression than hips treated with CD alone (P
EXTRACORPOREAL SHOCKWAVE THERAPY
Wang et al compared the results of ESWT with non
vascularized fibular grafting in 23 patients.
At a mean of 25 months, 79% of the ESWT
recipients had improved HHS as compared to only
29% of those with non-vascularised fibular grafting
Treatment for osteonecrosis of the femoral head: comparison of extracorporeal shock waves with core decompression and
bone-grafting. Wang CJ, Wang FS, Huang CC, Yang KD, Weng LH, Huang HY. J Bone Joint Surg Am. 2005 Nov;
HYPERBARIC OXYGEN (HBO)
Thus reducing intraosseus pressure and improving
Reis et al, reported the use of HBO in 12 patients
(16 hips) with Steinberg stage 1 disease. Each
patient was given 100% oxygen via a mask at 2-2.4
atmospheres for 90 minutes for 100 consecutive
They reported that 13 of the 16 femoral heads
subsequently appeared normal on MRI after this
Hyperbaric oxygen therapy as a treatment for stage-I avascular necrosis of the femoral head. Reis ND, Schwartz O, Militianu D,
Ramon Y, Levin D, Norman D, Melamed Y, Shupak A, Goldsher D, Zinman C. J Bone Joint Surg Br. 2003 Apr; 85(3):371-5.
§ Total Hip
§ Hip Resurfacing
Based on the concept that increased intramedullary
pressure is involved in the pathogenesis of AVN.
Wang et al have shown short term effect of
increased femoral head blood flow due to core
decompression in the rabbit model.
Core decompression is expected to relieve pain &
to allow creeping substitution to the necrotic area
by bringing the blood supply through th drill
The effect of core decompression on femoral head blood flow in steroid-induced avascular necrosis of the femoral head.
Wang GJ, Dughman SS, Reger SI, Stamp WG. J Bone Joint Surg Am. 1985 Jan; 67(1):121-4.
A meta-analysis of 24 reports
analyzing 1206 hips treated
with or without cancellous
bone grafting revealed an
overall clinical success rate of
63.5%. Less than 33% of the
hips required a replacement
or salvage procedure during
the follow-up period.
Core decompression versus nonoperative management for osteonecrosis of the hip.Mont MA, Carbone JJ, Fairbank AC. Clin
Orthop Relat Res. 1996 Mar; (324):169-78.
Conventional method involves the use of an 810mm trephine or cannula inserted under
flouroscopic guidance to penetrate the lesion.
Kim et al compared the efficacy of two drilling
methods (multiple drillings vs conventional core
decompression)in treatment of pre collapse
osteonecrosis in 54 patients.
The average pre and post operative HHS were
The group that had undergone multiple drillings
(3mm drill bits) had significantly longer time before
collapse (42.3 m vs 22.6m)
Lower rates of collapse within 3 yrs after operation
(55% vs 85.7%)
Kim SY, Kim DH, Park IH. Multiple drilling compared with core decompression for the treatment of osteonecrosis of the femoral
head. J Bone Joint Surg Br. 2004;86:149
Currently recommended for the treatment of Ficat
stage 1 or 2A, small central lesions in young, nonobese patients who are not taking steroids.
Campbell’s Operative Orthopedics. 12th Edition
USE OF OSTEOINDUCTIVE SUBSTANCES
ALONG WITH CORE DECOMPRESSION
Bone Morphogenic Proteins:
Lieberman et al suggested that core decompression
may be more effective if combined with BMP and/or
Treatment of osteonecrosis of the femoral head with core decompression and human bone morphogenetic protein. Lieberman
JR, Conduah A, Urist MR. Clin Orthop Relat Res. 2004 Dec; (429):139-45.
Bone marrow mesenchymal cell grafting:
Mesenchymal stem cells (MSC) from adult bone
marrow are multipotent that can diff. into
fibroblastic, osteogenic, myogenic, adipogenic and
Osteonecrosis is associated with a decrease in
progenitor cells in the proximal femur.
MRI has shown that conversion of red to fatty
marrow occurs prematurely in some patients with
Fatty marrow conversion of the proximal femoral metaphysis in osteonecrotic hips. Koo KH, Dussault RG, Kaplan PA, Ahn IO,
Kim R, Devine MJ, Cui Q, Cho SH, Wang GJ. Clin Orthop Relat Res. 1999 Apr; (361):159-67.
As a consequence intramedullary vascularity is
altered and may be a predisposing factor to AVN.
Lack of osteogenic cells also can influence bone
repair which occurs after osteonecrosis.
The current guidelines are that these should be
instilled in a conc. of 2X106 stem cells in nontraumatic precollapse stage of AVN.
The use of percutaneous autologous bone marrow transplantation in nonunion and avascular necrosis of bone. Hernigou P,
Poignard A, Manicom O, Mathieu G, Rouard H. J Bone Joint Surg Br. 2005 Jul; 87(7):896-902
Various studies e.g. Gangji et al (2005), Yan et al
(2006), Deltro et al (2008) have concluded that
percutaneous decompression augmented by MSC
implantation is safe and more efficacious than
Treatment of osteonecrosis of the femoral head with implantation of autologous bone-marrow cells. Surgical technique. Gangji V,
Hauzeur JP. J Bone Joint Surg Am. 2005 Mar; 87 Suppl 1(Pt 1):106-12.
Treatment of osteonecrosis of the femoral head by percutaneous decompression and autologous bone marrow mononuclear cell
infusion. Yan ZQ, Chen YS, Li WJ, Yang Y, Huo JZ, Chen ZR, Shi JH, Ge JB. Chin J Traumatol. 2006 Feb; 9(1):3-7
Daltro GC, Fortuna VA, Salvino de Araújo SA, FerrazLessa PI, Sobrinho UA, Borojevic R. Femoral head necrosis treatment with
autologous stem cells in sickle cell disease. Acta Orthop Bras. 2008;16:44–8.
Bone grafting procedures are a group of joint
preserving techniques that involve the removal of
the diseased femoral head segment, followed by its
replacement with 1 or more of a variety of bone
These are most valuable in treating patients with
Stage I & II disease
TECHNIQUES OF BONE GRAFTING
Grafting through lateral core track
Grafting through femoral neck window
Grafting through articular surface window
Avoidance of surgical dislocation of the hip
Low Complication Rate
Can be performed bilaterally under one anesthetic
Disadvantages:Inability to directly visualize the joint surfaces
Inexact nature of removing diseased bone & replacing it
with bone graft under fluoroscopic guidance
Risk of postoperative #
LIGHT BULB PROCEDURE
A window is created to expose the
anterior femoral neck, at the level
of the junction of the femoral head
When Combined with a Bone
Grafting procedure, referred to as
the “light bulb” procedure.
Advantage is the improved
access to the necrotic femoral
head segment & the avoidance of
direct iatrogenic cartilage damage
Disadvantage is the creation of
a cortical defect in the femoral
neck, which raises the risk of
The 3rd method of accessing the necrotic segment of the femoral head is known as
the “Trapdoor” approach
With this method, the hip is surgically dislocated using a technique aimed at
preserving the blood supply to the femoral head & neck
Once exposed, a “trapdoor” window is made in the femoral head cartilage to
access the diseased subchondral bone
When combined with a bone grafting procedure, referred as the “Trapdoor”
Advantage : Exposure allows a direct evaluation of the cartilage surface &
underlying diseased femoral head segment & allows for
precise bone graft placement.
Disadvantage : Demanding technical nature
Iatrogenic cartilage damage & osteonecrosis
Most authors recommend non-vascularised bone
grafts for hips with less than 2mm of femoral head
depression or those in which core decompression
has failed and there is no acetabular involvement
(Ficat stage 1 and 2)
Campbell’s Operative Orthopedics. 12th edition
cortical bone grafts
are typically prepared
as several struts that
support under the
articular surface within
the evacuated segment
This construct is often
cancellous bone graft
in an effort to improve
Local pedicled grafts
,which do not require
grafts, which require
POROUS TANTALUM ROD INSERTION
A novel approach in the treatment of stage I & II precollapse osteonecrosis
This rod functions analogously to a Cortical Strut Graft allowing
structural & osteoconductive properties
The main biomechanical effect is to rotate the
necrotic or collapsing segment of the hip out of the
weight bearing zone, replacing it with a segment of
articular cartillage of the femoral head supported by
healthy viable bone.
Additionally, may also reduce venous hypertension
and decrease intramedullary pressure.
TYPES OF OSTEOTOMIES
2 main types have been described:
Trans-trochanteric rotational osteotomy
Intertrochanteric varus or valgus osteotomy(usually
combined with either flexion or extension)
IDEAL PATIENT FOR OSTEOTOMY
Not being treated with long term steroids
Minimal osteoarthritic changes, with no loss of joint
space or acetabular involvement
Small combined necrotic angle
Subsequent conversion to THR may be difficult
Shannon BD, Trousdale RT. Femoral osteotomies for avascular necrosis of the femoral head. Clin Orthop Relat Res.
VALGUS OSTEOTOMY WITH FLEXION AND
THR has a higher rate of failure in this cohort.
May be because of the relative youth of these
patients and lack of other factors limiting physical
Accordingly, temporizing procedures have evolved
Total resurfacing arthroplasty
Resurfacing procedures have demonstrated clinical
but current short- and long-term results for
resurfacing procedures remain variable
Schmalzried TP. Total resurfacing for osteonecrosis of the hip. Clin Orthop
Relat Res. 2004;429:151-156.
Adili A, Trousdale RT. Femoral head resurfacing for the treatment of
osteonecrosis in the young patient. Clin Orthop Relat Res. 2003;417:93-101.
Grecula MJ. Resurfacing arthroplasty in osteonecrosis of the hip. Orthop Clin
North Am. 2005;36(2):231-242.
TOTAL HIP ARTHROPLASTY
TOC for advanced osteonecrosis of the hip
(University of Pennsylvania Stages IVB–VIC)
Excellent pain relief & functional improvements
More recent studies at intermediate follow up up to
10 years have demonstrated similar survivorship
compared to total hip replacement for
Kim YH, Oh SH, Kim JS, et al. Contemporary total hip arthroplasty with and without cement in patients with osteonecrosis of the
femoral head. J Bone Joint Surg Am. 2003;85-A(4):675-681.
Operated at Ortho Unit-I
Bone & Joint Surgery Hospital
• Name: Shareef Ahmad
• Dx: Idiopathic AVN
• Rx: Non-cemented total hip