Osteonecrosis of the femoral head (ONFH) is a series of pathological changes and clinical manifestations in which the blood supply to the femoral head is impaired or interrupted, resulting in the death of bone marrow components and bone cells, followed by repair and subsequent structural changes or even collapse of the femoral head.
Who are the frequent patients of osteonecrosis of the femoral head?
The groups at risk for ONFH include
① Hip trauma: femoral head and neck fracture, acetabular fracture, hip dislocation, severe sprain of the hip or contusion with intra-articular hematoma;
② Prolonged high dose application of glucocorticoids;
③Long-term heavy alcohol consumption;
④High coagulation and low fibrinolytic tendency and autoimmune disease, use of GCs;
⑤ history of decompression chamber work.
How to stage femoral head necrosis?
ONFH is classified according to clinical manifestations (Table 1).
①Pre-clinical (stage I): no symptoms and signs;
②Early stage (stage II): no symptoms or only mild hip discomfort, including discomfort in the groin or greater trochanter, hip pain with strong internal rotation, and no significant impairment of joint movement;
③Pre-collapse stage (middle stage, stage III): more severe acute hip pain, mild claudication, limited internal rotation, and increased pain with strong internal rotation;
(iv) Collapse stage (middle and late stage, stage IV): moderate to severe pain, limp, and moderate limitation of internal rotation and abduction of joint flexion;
⑤ Osteoarthritis stage (late stage, stage V): severe pain, increased claudication, significantly limited joint movement (flexion, internal rotation, internal rotation), joint deformity (flexion external rotation, internal rotation).
(Click on the picture to see more clearly)
How is femoral head necrosis classified?
Based on the femoral head site occupied by the necrotic foci, our consensus adopts the China-Japan Friendship Hospital (CJFH) staging (Figure 1), which is divided into
M type (medial type) – necrotic foci occupy the medial column;
C-type (central type) – necrotic foci occupy the central column;
Type L1 (sub-lateral) – necrotic foci occupy the lateral, middle and medial columns, but the lateral column is partially preserved;
Type L2 (extreme lateral) – necrotic foci occupy the lateral column, with the central and medial columns remaining;
L3 (total femoral head type) – necrotic foci occupy the whole femoral head.
How to detect femoral head necrosis among millions of diseases?
Diagnosis can be made by meeting one of the following tests.
1.X-ray: necrotic foci are surrounded by sclerotic bands, segmental collapse, crescentic sign, femoral head collapse but joint space is maintained.
2) MRI: T1WI, banded low signal; T2WI, double line sign; T2WI lipid suppression, high signal band around the circumference of the necrotic foci; T2WI lipid suppression, bone marrow edema of the femoral head and neck in addition to the focal area, and T1WI is banded low signal.
3) CT: well-defined necrotic foci with subchondral fractures.
How is the differential diagnosis of femoral head necrosis?
ONFH is generally not difficult to diagnose, but should be differentiated from the following diseases.
1, MRI shows painful hip disease with bone marrow edema in the femoral head and neck;
2, temporary osteoporosis;
3, osteochondral lesions (subchondral incomplete fracture, intra-femoral head tumor);
4, hip diseases originating from cartilage (idiopathic osteoarthritis in young and middle-aged people, hip dysplasia secondary to osteoarthritis, ankylosing spondylitis, rheumatoid arthritis);
5, hip synovial lesions (hyperpigmented villous nodular synovitis, synovial osteochondromatosis)
K.O femoral head necrosis, clinical swelling do?
1, drug treatment.
For early ONFH can be used anticoagulation, pro-fibrinolytic, vasodilator drugs, such as low-molecular heparin, prostaglandin, etc. Application of drugs to inhibit osteolysis and increase osteogenesis, such as phosphate preparations, methyldopa, etc.. Depending on the situation of necrosis, drugs can be used alone or in combination with hip preservation surgery.
2.Hip preservation surgery treatment Hip preservation surgery treatment
Marrow core decompression or combined with autologous bone marrow single nucleus cell implantation: it is still in the experimental stage and should be used with caution;
Focal clearance, bone grafting with or without hematopoiesis: the accesses for focal clearance include trans-femoral subtrochanteric, anterior trans-femoral, cervical junction opening and trans-femoral cartilage flap;
Osteotomy: there are rotational osteotomy of the femoral head and neck via the greater trochanter, and inversion osteotomy of the femoral head and neck via the inferior trochanter. The selection of tantalum rods should be cautious, and transcatheter intervention alone is not recommended.
3.Artificial joint replacement
A significant proportion of ONFH patients eventually have to receive artificial joint replacement, there are generally four kinds.
① surface replacement: limited indications, not suitable for necrosis volume is large, gold on the gold bearing surface complications make the application of the amount of decline.
② Femoral head replacement: limited indications due to unpredictability of postoperative pain and acetabular wear.
③Total hip arthroplasty with a short-stemmed femoral prosthesis: in development.
④Total hip arthroplasty: it is the most classic and models mature, the effect is definitely lasting artificial joint surgery, applicable to most of the stage IV and V ONFH patients, for middle-aged and young patients it is recommended to use wear-resistant load-bearing surface (tau to tau, tau to high cross-linked polyethylene), biological bone growing into the type of prosthesis.
What are the treatment principles for different stages and subtypes of femoral head necrosis?
①Stage I and II, type M: perform follow-up, observation or comfort treatment.
②Stage I and II, type C: extracorporeal shock wave, medullary decompression or lesion removal, autologous bone marrow transplantation or compression osteotomy, and drug treatment.
③Stage Ⅰ, Ⅱ, L1 type: focal removal, support bone graft (bone graft with blood vessels or blood transport) or compression bone grafting, drug treatment; <35 years old can choose inversion osteotomy.
(④Stage I and II, L2 and L3 types: lesion removal, support bone graft (with blood vessels or with blood transport bone graft) or compression bone grafting; trans-femoral rotational osteotomy can be chosen for L2 types <35 years old.
⑤ Stage Ⅲ: for <50 years old, hip preservation is the main method, and the method is the same as ④; for >50 years old, artificial arthroplasty can be chosen because of heavy pain and poor joint function.
(6) Stage IVa and IVb: those <40 years old should try to preserve the hip; those >40 years old can choose artificial arthroplasty because of heavy pain and poor joint function.
(vii) Stage IVc, V: artificial joint replacement can be chosen because of heavy pain and poor joint function.