This document discusses osteonecrosis of the femoral head, including risk factors, pathogenesis theories, classifications, diagnosis, and treatment options. Key points: - Risk factors include corticosteroid use, smoking, sickle cell anemia and others. Theories on causes include toxicity, vascular issues, but the process is likely multifactorial. - Diagnosis involves radiographs, bone scans and MRI, which can detect early-stage disease. - Treatment depends on disease stage and size. Options include core decompression, bone grafting, osteotomies and arthroplasty. Younger patients with smaller lesions may be candidates for bone-preserving options, while larger lesions often require joint replacement.

1. OSTEONECROSIS OF THE
FEMORAL HEAD
Dr. morteza dehnokhalaji
TUMS
2016

2. risk factors
• Trauma
• Corticosteroid use
• alcohol abuse
• Smoking
• Hemoglobinopathies (e.g., sickle cell anemia)
• coagulation disorders
• Myeloproliferative disorders (Gaucher disease, leukemia)
• caisson disease
• HIV infection
• Pregnancy
• idiopathic osteonecrosis.

3. theories on the pathogenesis
1. direct cellular toxicity
2. coagulopathic states
3. hyperlipidemia with fat emboli
4. vascular interruptions or abnormalities
5. elevated bone marrow pressure
• None of these theories can fully account for the variety of
causes.
• Most patients with the risk factors just mentioned never
develop osteonecrosis
• many patients without identifiable risk factors do acquire
the disease.
• process is most likely multifactorial.

4. CLASSIFICATIONS

6. DIAGNOSIS
• Patients are typically asymptomatic early
• eventually have groin pain on ambulation.
• Plain radiographs should be obtained
– AP and frog-leg lateral views
• Radiographic changes
• normal in the early stages
• increased density or lucency in the femoral head.
• the pathognomonic crescent
– best seen on frog-leg lateral views
• In the end stages of the disease
– femoral head collapse
– severe arthritic changes

7. Bone scanning
• useful, especially in assessing the status of
multiple joints
• The uptake of technetium-99m
– decreased in the very early stage of disease
– variable or increased at a stage when symptoms
occur
• there is no relationship between the
scintigraphic appearance of the femoral head
and the pain and function of the hip

8. MRI
• earlier diagnosis
• allow determination of the exact stage and extent of the
pathological process without use of invasive methods.
• Differentiation between transient osteoporosis and
osteonecrosis
• useful in following the progression of the disease
• evaluating the efficacy of treatment.
• When plain radiographs show changes in only one joint
– define clearly the extent of the disease in the symptomatic hip
– evaluate the asymptomatic hipallow detection of the disease
in the early stages when most treatments are more effective

9. TREATMENT
• the rate of progression is high, especially in symptomatic
patients
• Asymptomatic osteonecrosis
– the lesion < 30% of the area of the femoral head  remain
asymptomatic in most patients (95%) for > 5 years
– lesion size increased the percentage of painful osteonecrosis
increased up to 83% in hips with large lesions (>50% of the
area of the femoral head)
• When subchondral collapse occurs and joint space is lost
inevitable progressive osteoarthritis
• extremely poor prognosis, with a rate of femoral head
collapse of greater than 85% at 2 years in symptomatic
patients (stage I or II disease)

10. core decompression
• The theoretical advantage
– relieves intraosseous pressure caused by venous
congestion improved vascularity  possibly
slowing the progression of the disease
• the results of core decompression are better
than the results of nonoperative treatment
• the earlier the stage of the diseasethe
better the results
• the best results reported in stage I hips

11. core decompression
• INDICATIONS:
– Ficat stage I and IIA
– small central lesions in young
– Non obese patients who are not taking steroids
• ADVANTAGES:
– relatively simple to perform
– a very low complication rate
– The surgical field for subsequent total hip arthroplasty, if needed, is
not substantially altered
• For more advanced Ficat stages (IIB or III):
– the results of core decompression are much less predictable,
– so alternative treatment methods should be explored
• > 30% of patients, even with early-stage disease, will likely require
THA within 4 to 5 years of core decompression surgery

13. POSTOPERATIVE CARE
• Partial weight bearing (50%) on crutches for at
least 6 weeks
– protect the cortical window
• In patients with advanced disease, protected
weight bearing is prolonged.

14. CORE DECOMPRESSION—
PERCUTANEOUS TECHNIQUE
• using multiple small drillings with a 3.2-mm
Steinmann pin
• lower rate of femoral head collapse
• low morbidity
• few or no surgical complications.

16. POSTOPERATIVE CARE
• Physical therapy
– Gait reconditioning with a cane or crutches
• Protected weight bearing (approximately
50%) for 5 to 6 weeks  then advanced to full
WB as tolerated
• High-impact loading such as jogging or
jumping is not permitted for 12 months

17. BONE GRAFTING
• Successful results after core decompression with
structural bone grafting 50% to 80%
• No difference between tibial or fibular
autogenous grafts and fibular allografts
• comparing vascularized and nonvascularized
fibular grafts for large lesions (>30% of the
femoral head)
– better clinical results and more effective prevention
of femoral head collapse with vascularized grafting

18. • nonvascularized bone grafts
– less than 2 mm of femoral head depression
– core decompression failed
– no acetabular involvement (Ficat stage I or II)
• The bone grafts technique
– standard core track technique, “trapdoor”
technique
– “lightbulb” technique

20. VASCULARIZED FIBULAR GRAFTING
• good results in 80% to 91%
• reasonable option for patients younger than 50
years without collapse of the femoral head
• for patients older than 50 THA is indicated if
symptoms warrant surgical intervention
• Concurrent steroid use is not a contraindication
for this procedure
• not indicated for patients with asymptomatic
early-stage osteonecrosis because the results of
core decompression are equally effective for this
group of patients.

22. PROXIMAL FEMORAL OSTEOTOMY
• move the involved necrotic segment of the
femoral head from the principal weight-bearing
area. These procedures have achieved
• best results for small-sized or medium-sized
lesions (<30% femoral head involvement) in
young patients(<55Y) in whom it is optimal to
delay a THA
• idiopathic or posttraumatic osteonecrosis did
better than alcohol-induced or steroid-induced
necrosis.

23. • A valgus-extension intertrochanteric
osteotomy combined with curettage of the
avascular segment and autogenous bone
grafting was reported to have an 87% success
rate at 65 months.

24. • A transtrochanteric
rotational osteotomy

25. RESURFACING HEMIARTHROPLASTY
• If osteonecrosis involves >30% of the head
• an attractive alternative for young patients
with advanced osteonecrosis because very
little bone is sacrificed

26. TOTAL HIP ARTHROPLASTY AND
BIPOLAR HEMIARTHROPLASTY
• Most series that have examined unipolar and
bipolar hemiarthroplasty for the treatment of
osteonecrosis have reported uniformly poor
results.
• The results of primary total joint replacement
for osteonecrosis are now approaching the
results reported for osteoarthritis in age-
matched patients.