I. What is femoral head necrosis?
Femoral head necrosis, known as aseptic necrosis of the femoral head or ischemic necrosis of the femoral head, is a lesion caused by localized poor blood flow to the femoral head for various reasons, which leads to further ischemia, necrosis of bone cells, fracture of bone trabeculae, and collapse of the femoral head. Femoral head necrosis has become a multiple and common disease. Especially since the introduction of hormones and their widespread use, the incidence of femoral head necrosis has gradually increased. At present, there are about 30 million people suffering from this disease worldwide, and about 4 million in China. The latest survey shows that there is no significant gender difference in the occurrence of this disease, and it can occur at any age, while the incidence of the disease is significantly increased in people with a history of hormone application, hip trauma, alcohol abuse, and related diseases.
The disease can occur at any age but is most common between the ages of 31 and 60, with no gender difference. It starts with vague or dull pain in the hip joint or its surrounding joints, which worsens after activities.
Second, the clinical manifestation and diagnosis of femoral head necrosis
The clinical symptoms of osteonecrosis of the femoral head vary depending on the location and the size of the necrosis, most of the intra-medullary osteonecrosis is static and has no clinical symptoms, while small osteonecrosis has symptoms but has less impact on the function. Pain is often the main symptom of osteonecrosis, usually chronic and vague, in some cases the symptoms can be more severe, the pain can gradually increase with joint activity, and finally develop to pain even at rest, often need to take drugs to relieve. The affected joints are often restricted in movement, sometimes with localized pressure pain and claudication, and in severe cases, complete bilateral necrosis and resorption of the femoral head, making standing and walking impossible. In milder cases, if ischemic necrosis of the femoral head is suspected, further special tests must be done. We would like to emphasize the importance of using MRI examination for early diagnosis of ischemic necrosis of the femoral head. MRI examination is the most accurate among the existing examination methods, and nearly 500 cases of Ficat I and II treated by the authors were found to have no significant abnormalities on X-ray, while osteonecrosis was found on MRI examination. Therefore, MRI of both hips should be considered for patients with hip pain symptoms and no obvious abnormalities on X-ray radiographs. It is also feasible to include X-ray film, CT, MRI, nuclear bone scan, intramedullary pressure determination, tissue biopsy, etc.
Third, how to stage femoral head necrosis
Understanding the staging of femoral head necrosis has a very important role in the selection of treatment methods. There are many staging methods for femoral head necrosis, including Marcus, Ficat and Arlet, Steinberg and ARCO (Association for Research in Microcirculation of Bone), etc. Ficat and Arlet divide the ischemic necrosis of femoral head with clinical symptoms and confirmed by woven biopsy into four stages according to the X-ray performance. Stage II has a normal femoral head appearance but shows significant bone repair, including cystic degeneration and osteosclerosis. The radiolucent area seen on the X-ray shows histologically the area of bone resorption and the corresponding fibrous or granulation tissue. The osteosclerotic area is histologically represented by new bone overlying the dead bone at the edge of the necrotic area. In stage III, there is subchondral bone collapse or flattening of the femoral head. Stage IV shows joint space narrowing and secondary degenerative changes in the acetabulum (cystic degeneration, marginal bone formation, and cartilage destruction). When MRI was used to diagnose femoral head necrosis, Hungerford and Lennox combined MRI to add stage 0. The stage III of Ficat and Arlet’s staging was further divided into mild (less than 15% femoral head damage on X-ray), moderate (between 15% and 30% femoral head damage on X-ray), and severe (more than 30% femoral head damage on X-ray). The extent of femoral head damage on X-ray is greater than 30%). In view of the fact that the site of femoral head necrosis is related to its prognosis, the Association for Research in Osteomicrocirculation (ARCO) Committee on Nomenclature and Classification recommended its classification in an academic newsletter in 1993, combining the Ficat and Arlet classification system with the extent of femoral head damage and damage site, which is the most reasonable classification system at present, but its promotion still needs time.
Fourth, the common clinical treatment methods of femoral head necrosis
1.Non-surgical treatment
① Avoiding weight-bearing: including partial weight-bearing and non-weight-bearing, which is only applied to the necrosis of femoral head before collapse, i.e. Ficat I and II. From the literature, the effect of the treatment method of avoiding weight-bearing is not ideal, and the success rate is less than 15%. ②Pharmacological treatment: the application of drugs to treat femoral head necrosis is less reported, in short, the effect of drug treatment is not yet certain, but it is still an important research direction because of its non-invasive nature. ③Other treatment methods: such as electrical stimulation therapy, bloodletting therapy, hyperbaric oxygen therapy, etc., there are not many reports, and the effect needs to be further determined.
2.Surgical treatment
(1) Central decompression: The theory of central decompression for ischemic necrosis of femoral head is based on the theory of increased intraosseous pressure of osteonecrosis, which can reduce intraosseous pressure and increase blood flow in femoral head through central decompression, and central decompression can stimulate the growth of blood vessels in the decompression tunnel and promote the crawling replacement of necrotic bone. There are more articles about central decompression, and its efficacy is more controversial. Its efficacy is highly related to the stage of femoral head necrosis, and not much related to the etiology of femoral head necrosis.
(2) Osteotomy: The purpose of osteotomy is to change the main weight-bearing area of the femoral head, replacing the necrotic bone with normal bone as the main weight-bearing area. This method includes trans-rotor rotational osteotomy, inter-rotor internal osteotomy and inter-rotor external osteotomy, etc. It can also be combined with bone grafting treatment, mainly for patients with Ficat stage II and III and small lesions.
(3) Osteotomy: Osteotomy includes autologous cancellous bone graft, autologous cortical bone graft, allogeneic bone graft and cartilage graft, which can be combined with other treatment methods such as central decompression, electrical stimulation and osteotomy. Among them, autologous cancellous bone and cortical bone graft are more commonly used. Autologous cancellous bone has good osteogenesis induction and can promote the repair of necrotic femoral head, while cortical bone plays a supporting role for articular cartilage and subchondral bone in the necrotic area during the repair of femoral head. Bone grafting methods include bone grafting after central decompression, slotting bone grafting at the craniocervical junction, opening a window in the articular cartilage of the femoral head, lifting cartilage bone grafting and then resetting the cartilage. Bone grafting can be used in patients with Ficat stage II, early stage III and patients who have failed central decompression. The recent efficacy of this method is more certain, while the long-term efficacy is still controversial. However, it is worthwhile to accelerate the repair of the femoral head with the help of bone graft and shorten the bed rest time, and the combination of growth factors, electrical stimulation and other methods to promote bone healing can improve its efficacy.
(4) Bone graft with blood supply: There are more methods of bone graft with blood supply, and the grafted bone can come from the iliac bone, greater trochanter or fibula, and can be with myofibular or vascular tip, and the bone graft with blood supply can increase the blood supply to the femoral head and accelerate bone healing compared with ordinary bone graft. The clinical results are reported in the literature, but the X-ray improvement is not satisfactory, and a significant proportion of patients still need arthroplasty in the long-term follow-up.
(5) Hip arthroplasty: For advanced Ficat stage III or IV patients, total hip arthroplasty is the best choice.
V. Why artificial arthroplasty is needed for severe femoral head necrosis
Ischemic necrosis of the femoral head in adults mostly occurs in young and middle-aged people, the pathogenesis is still not very clear, it has been found that taking corticosteroids, trauma, alcohol abuse, high coagulation state can induce this disease, most patients will inevitably collapse of the femoral head if they do not receive treatment after the appearance of symptoms. The existing non-surgical and surgical treatments are not effective, and the success rate is less than 15% with weight-free treatment alone, while the efficacy of medullary decompression and bone graft with blood supply is not satisfactory either. For patients with advanced Ficat stage III or IV, total hip replacement is the best choice. There are two types of total hip prostheses: cemented and non-cemented. However, with the application of modern bone cement technology, the loosening rate of the prosthesis was significantly reduced, especially the cemented femoral stem prosthesis achieved satisfactory results, which made the cemented prosthesis popular again, but the loosening rate of the cemented acetabular prosthesis is still high. The non-cemented prosthesis has gradually gained attention since the 1980s, but there are problems of early micro-movement and subsidence of the prosthesis and high incidence of postoperative claudication and thigh pain, while the non-cemented acetabular prosthesis has achieved good early clinical results. The uncemented prosthesis is mainly used for young, well-boned or rehabilitated patients, while the cemented prosthesis is mainly used for older, osteoporotic patients. Since the postoperative effect of cemented femoral stem prosthesis is better than that of non-cemented type, and the non-cemented acetabular prosthesis is better than cemented type, the hybrid fixation of cemented femoral stem prosthesis and non-cemented acetabulum has gradually become popular in recent years. Unipolar or bipolar femoral head prosthesis hemi-acetabular replacement for femoral head necrosis has been discarded due to progressive wear of acetabular cartilage and loosening of the prosthesis, and the invasion of the bone marrow cavity is not conducive to rework. As patients with femoral head necrosis are relatively young, total hip replacement will eventually require revision surgery. Some people advocate that for patients with Ficat III stage acetabulum intact and younger, femoral head surface replacement should be performed, as this method preserves the intact bone bed, it is easy to perform revision surgery, and total hip replacement can be postponed, so it is a good excessive therapy.
VI. Femoral head necrosis
Early 3 signs femoral head necrosis is the destruction of blood supply to the femoral head joint surface tissue, resulting in ischemic necrosis of the femoral head. Femoral head necrosis is progressive, in the very early stage of the process the body issues some signals to draw the attention of patients, such as knee pain, claudication, hip pain.
1, knee pain
The early stage of femoral head necrosis is just a radiating pain in the knee joint, and this knee pain may continue for one or two years. This is a symptom that causes the most misdiagnosis rate in the early stage of femoral head necrosis, and it is also the culprit that causes the early stage of femoral head necrosis patients to lose the best time for treatment. Nearly 2/3 of patients with osteonecrosis of the femoral head will have knee pain in the early stage, and the appearance of this symptom will first be diagnosed as arthritis by the patients themselves or their doctors.
2.Crippling
The limping symptom in the early stage of femoral head necrosis patients does not attract attention. When the patient walks too long will feel the lower limbs sore and weak or limp, many people will consider this a normal phenomenon. However, when it is found that walking limp is reduced after rest, when sitting down with hip discomfort or soreness, you should be alert to the disease.
3.Hip pain
The symptom of hip pain, which many people will think is hip pain, may be misdiagnosed as sciatica or lumbar spine disease if the doctor does not examine it carefully. Hip pain is the most direct symptom manifestation of femoral head necrosis and should be examined in time to help correct diagnosis.
These three signs of early femoral head necrosis often appear singly and have a long course, resulting in a high rate of misdiagnosis.