Guidelines Summary
Japanese Orthopaedic Association guidelines for osteonecrosis of the femoral head (ONFH) include the following recommendations and statements [39] :
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Unloading for ONFH with orthotics (canes and crutches) is useful for alleviating alleviate pain and improving walking function, but cannot be expected to prevent the progression of collapse of the femoral head or reduce the need for surgical treatment in the long term.
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Extracorporeal shock waves, electromagnetic field stimulation, and hyperbaric oxygen therapy for ONFH may be effective in alleviating pain. It is unclear whether these therapies can prevent the progression of femoral head collapse or reduce the need for surgical treatment.
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The long-term effect of bisphosphonate (alendronate, zoledronate) administration for ONFH on the prevention of femoral head collapse is unclear.
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Short-term results of core decompression for Ficat stage I ONFH are good; however, this surgery should not be selected for ONFH with Ficat stage II or higher. As there have been several cases with poor improvement of pain and progression to collapse of the femoral head even in Ficat stage I, it is necessary to consider the surgical indications based on detailed evaluation of the size and position of the necrotic area. Core decompression combined with bone marrow-derived cells and/or growth factors is expected to improve clinical outcomes compared to core decompression alone; however, clinical outcomes are still poor for cases of Ficat stage III or more.
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The results of vascularized bone grafting vary among reports, but good clinical outcomes can be expected in 60%–94% of cases when arthritic changes have not appeared.
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Femoral varus osteotomy is useful to relieve symptoms and prevent the progression of ONFH with sufficient intact area at the lateral femoral head. Patients with a postoperative intact ratio of more than 34% generally have a good clinical outcome.
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Transtrochanteric rotational osteotomy is useful to relieve symptoms and prevent the progression of the stage of ONFH with a wide necrotic area.
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The long-term results of contemporary cementless total hip arthroplasty have been generally good, and it is an effective treatment option for patients with low levels of osteolysis around the implant, dislocation, and deep infection.
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The long-term results show that cemented total hip arthroplasty have using modern cementing techniques is a generally good and useful treatment; however, there are fewer long-term reports on cemented acetabular components than on femoral components. The longevity of cemented acetabular components is slightly inferior to that of the femoral components.
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Bipolar hemiarthroplasty is indicated for ONFH at stage 3 or earlier without osteoarthritic changes. The mid-to long-term results of bipolar hemiarthroplasty for ONFH in stage 3 and earlier are generally good, making it a useful treatment; however, postoperative buttock and groin pain and migration of the outer head may occur.
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The short-to mid-term results of hip resurfacing arthroplasty for ONFH are generally good; however, there are few reports on its long-term results. An increase in serum metal ion concentration and the occurrence of femoral neck fracture have been reported. Indications must be strictly considered.
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Hip replacement for young people (age 50 years or less) is one of the most useful treatments for ONFH, with good mid-term results; survival rates in highly active young patients are 100% at 7–10 years postoperatively, when ceramic-on-ceramic or highly cross-linked polyethylene is used for bearing. However, long-term results need further verification. In addition, if a blood disorder such as sickle cell disease is involved in the occurrence of ONFH, the incidence of complications may increase and the implant survival rate may decrease.
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Osteonecrosis, hip. Anteroposterior radiograph showing Ficat stage III disease.
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MRI showing osteonecrosis of right hip, normal left hip.
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Bone scan showing osteonecrosis of right hip.
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Osteonecrosis, hip. Anteroposterior radiograph core biopsy.
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Osteonecrosis, hip. A radiograph of a limited femoral resurfacing performed for a collapsed femoral head with damaged femoral head cartilage and intact acetabular cartilage.
Tables
Stage |
Criteria |
0 |
Normal radiograph, bone scan, and magnetic resonance images |
I |
Normal radiograph. Abnormal bone scan and/or magnetic resonance images A: Mild (< 15 % of femoral head affected) B: Moderate (15–30 % of femoral head affected) C: Severe (>30 % of femoral head affected) |
II |
Cystic and sclerotic changes in femoral head A: Mild (< 15 % of femoral head affected) B: Moderate (15–30 % of femoral head affected) C: Severe (> 30 % of femoral head affected) |
III |
Subchondral collapse without flattening (crescent sign) A: Mild (< 15 % of femoral head affected) B: Moderate (15–30 % of femoral head affected) C: Severe (>30 % of femoral head affected) |
IV |
Flattening of femoral head A: Mild (< 15 % of surface and < 2 mm of depression) B: Moderate (15–30 % of surface and 2–4 mm of depression) C: Severe (>30 % of surface and > 4 mm of depression) |
V |
Joint narrowing or acetabular changes A: Mild B: Moderate C: Severe |
VI |
Advanced degenerative changes |
Stage |
Criteria |
0 |
Bone biopsy results consistent with osteonecrosis; other test results normal |
I |
Positive findings on bone scan, MRI, or both A: < 15% involvement of the femoral head (MRI) B: 15-30% involvement C: > 30% involvement |
II |
Mottled appearance of femoral head, osteosclerosis, cyst formation, and osteopenia on radiographs; no signs of collapse of femoral head on radiographic or CT study; positive findings on bone scan and MRI; no changes in acetabulum A: < 15% involvement of the femoral head (MRI) B: 15-30% involvement C: > 30% involvement |
III |
Presence of crescent sign lesions classified on basis of appearance on AP and lateral radiographs A: < 15% crescent sign or < 2-mm depression of femoral head B: 15-30% crescent sign or 2- to 4-mm depression C: > 30% crescent sign or > 4 mm depression |
IV |
Articular surface flattened; joint space shows narrowing; changes in acetabulum with evidence of osteosclerosis, cyst formation, and marginal osteophytes |
