Femoral head necrosis is a common orthopaedic disease, which is a serious threat to human health and has become a hot spot of concern in the world of orthopaedics.
Definition】：Our experts suggest to combine the standards of the International Association of Bone Circulation Research (ARCO) and the American Academy of Orthopaedic Surgeons (AAOS) to define femoral head necrosis as (2006): Femoral head necrosis is a disease in which the blood supply to the femoral head is interrupted or damaged, causing the death of bone cells and bone marrow components and subsequent repair, which then leads to structural changes in the femoral head, femoral head collapse and joint dysfunction.
[Classification]: Traumatic osteonecrosis of the femoral head: it can be seen in femoral neck fracture, femoral head fracture, hip dislocation, hip dislocation and femoral neck or femoral head fracture. Non-traumatic femoral head necrosis: common causes: alcoholism, hormonal orthopedic common diseases, mostly seen in young and middle-aged people, mostly bilateral onset. Idiopathic femoral head necrosis: without any clear causative factors.
[Diagnosis]: Early diagnosis is difficult, and etiologic history is particularly important. In non-traumatic femoral head necrosis, it is often found that early femoral head necrosis has occurred on the opposite side when symptoms appear on one side for adjuvant MRI. Patients with a history of alcoholism and long-term hormone application are more vigilant and can detect femoral head necrosis early by taking the initiative to seek medical attention or by early MRI examination. In contrast, the X-ray manifestations of ARCO stage II and advanced cases are already obvious and easy to diagnose. The main points of diagnosis include: focus on understanding the medical history, careful physical examination, and early auxiliary examination.
1.X-ray: suitable for observing the morphology of femoral head (roundness, height, degree of collapse), but its sensitivity is poor.
2, CT: sensitivity is significantly lower than MRI, I do not recommend this examination.
3, ECT: sensitivity is better than CT, careful observation does have a cold zone, which can be detected at an extra early stage (stage 0 or pre-I). The presence of a hot zone, combined with the medical history, can help in the diagnosis. However, the specificity is poor. The femoral head/stem ratio should be measured for uptake of radionuclide counts (Wang Yisheng, 1996), and the mean head/stem ratio of normal adults is 2.5, and its positive result is 93.8% in accordance with the positive MRI result. Combined with the medical history (especially those who apply a lot of hormones and drink a lot of alcohol), femoral head necrosis should be suspected when the head/stem ratio is greater than 2.5, and when the head/stem ratio is greater than 3.0, it should be highly Suspected or can be initially diagnosed as femoral head necrosis.
4, MRI: the sensitivity is particularly high, and the sensitivity and specificity of early detection and diagnosis of femoral head necrosis reaches 99%, which should be preferred for the screening of early femoral head necrosis.
5.Functional bone examination (FBE): intraosseous pressure measurement, intraosseous venography, core biopsy. Normal intraosseous pressure of femoral head in adults: 2.67~4.00kPa (20~30mmHg), intraosseous pressure of femoral head necrosis: > 4.00kPa (30mmHg). Femoral head core biopsy has the most accurate results, and its disadvantage is that it is an invasive test.
【Treatment principle】: Making the correct diagnosis and staging is the key to decide the treatment plan. There are different staging methods for femoral head necrosis, each with its own advantages and disadvantages. Currently commonly used staging methods: treatment methods for ARCO staging.
Stage 0~II-A: medullary core decompression
Stage II-B ~ III-B: Osteotomy or bone grafting
Stage III-C ~ Stage IV: Artificial hip arthroplasty
Staging series therapy】.
Adhere to the principle of head-preserving treatment and adopt the new staged surgical therapy in order to obtain better results. First of all, accurate diagnosis, according to the patient’s age, etiology, medical history, stage, rate of progression, necrosis area, necrosis location, risk of collapse, degree of collapse and other various factors, analyze the individual characteristics of each case and develop an individualized treatment plan.
I. Conservative treatment
Early stage cases (0~I-A stage), without symptoms, can be treated conservatively.
1.Drugs Apply blood-activating and stasis-transforming Chinese herbs, geranium, Xianlingbao, lipid-lowering drugs, etc. It is best used for those with pre-I stage, which may receive certain effect. And it is difficult to find patients with stage or pre-I clinically. Therefore, prevention becomes very important.
2.Shockwave, hyperbaric oxygen, blood purification, etc.: clinical efficacy is to be observed in the long term.
Second, staged surgery therapy
For those who are diagnosed with femoral head necrosis and have symptoms, we adopt the following staged surgical therapy for femoral head necrosis with reference to ARCO international osteonecrosis staging standards.
(A) Stage 0~I-A
A 3~4mm fine needle borehole decompression procedure is administered. The purpose is to decompress the femoral head, open up the sclerotic zone, and induce increased blood circulation to the necrotic area. Autologous bone marrow cells or 2nd generation bone marrow stem cells can also be implanted at the same time.
(II) Stage I-A, I-B, II-A
A 10 mm diameter thick channel marrow core decompression is administered. The purpose is also to decompress the femoral head, open up the sclerotic zone and induce increased blood circulation to the necrotic area. Autologous bone marrow cells, bone marrow stem cells, autologous iliac bone, allogeneic bone, and osteoinductive active material can be implanted simultaneously to promote bone repair.
(III) Stage I-C, II-A, II-B, II-C
Bone grafting is administered. Objective: To completely remove necrotic bone, adequately implant bone, rebuild blood circulation, promote bone repair, restore biomechanical strength within the femoral head, and prevent collapse. The results of our previous studies showed that the results of coarse channel core decompression showed that the results of stage I-C were not as effective as those of stage II-A because of the large necrotic area (more than 30% of the femoral head), so it was considered appropriate to perform bone grafting for stage I-C. The efficacy of coarse channel core decompression for stage II-A was not as effective as those of stages I-A and I-B, and the lesion had progressed one level compared with stage I. Therefore, it was considered that coarse channel core decompression for stage II-A was feasible. However, bone grafting is more recommended.
(IV) Stage III-A~III-B
Bone grafting can still be performed in this stage. However, because the femoral head has collapsed and the lesion has escalated, the results of bone grafting are not as good as those in stage II. Some people advocate that artificial joint replacement (surface or total hip) can be considered for symptomatic stage III-B patients older than 40 years old, i.e., femoral head collapse of 2~4 mm.
Artificial joint replacement can be adopted.
(E) Stage III-C and IV Artificial hip replacement should be considered, which is an effective method for treating advanced femoral head necrosis.
Introduction of surgical methods.
(a) Decompression surgery The purpose is to decompress the femoral head, open up the sclerotic zone, promote increased blood circulation to the necrotic area, and promote bone repair. This method is less invasive, simple and easy to perform.
1. Fine needle drilling decompression surgery
2.Bone marrow core decompression with osteoinductive material (BMP) implantation or bone marrow stem cell transplantation
(B) Bone grafting: There are two types of bone grafting methods currently used: free fibula grafting with anastomosis of blood vessels and bone flap grafting with myotomy or vascular tissues.
1, the purpose of bone grafting
(1) To completely remove necrotic bone, implant bone flap (column) containing cortical bone or and metal support, repair collapse, restore the height of the femoral head, increase the support strength and support range, and improve its biomechanical properties;
(2) Provide blood flow and adequate bone grafting (bone marrow mass, bone strip, bone flap) or implant bone marrow cells, stem cells, and osteoinductive active material to promote bone repair (endograft reossification of the femoral head);
(3) To relieve hip joint pain, restore function and improve quality of life;
(4) Avoid or delay artificial prosthesis replacement, and do not prevent future artificial prosthesis replacement.
2.Indications for bone grafting
(1) Indications: Bone grafting is suitable for ARCO I-C, II-A, II-B, II-C stage femoral head necrosis. It can also be used for those with stage III-A and III-B, but the effect is not as good as that of those with pre-collapse.
(2) Not suitable for: those with ruptured or defective cartilage surface of the femoral head, those with severe collapse of the femoral head or simultaneous acetabular lesions. generally not used for patients over 50 years old.
(3) Artificial hip arthroplasty (THA)
The long-term efficacy of THA, whether cemented or non-cemented, for osteonecrosis is inferior to that of THA for other diseases, so we should provide clear preoperative information, precise and standard surgical operation, pay attention to the patient’s postoperative recovery, actively follow up, familiarize the patient with the precautions to be taken in life and work, and guide him/her to move and use the artificial joint correctly in order to prolong the service life of the artificial prosthesis.