Femoral head necrosis is caused by ischemia of the femoral head, so it is also called “ischemic necrosis”, and other bones in the human body can also develop, collectively called “osteonecrosis”. The common causes are “trauma” (such as femoral neck fracture, hip dislocation, femoral head crush injury, etc.), diving decompression disease, long-term use of hormonal drugs, gout, rheumatoid, congenital hip dysplasia, etc. It can be clinically divided into four stages: Stage I: clinical symptoms are not obvious, only hip discomfort after exertion. changes on X-ray and CT are not obvious or there are dotted density changes, MRI and bone isotope scan can be found. Stage II: discomfort or pain in the hip after exertion, which may radiate into the knee and improve after rest, with slight density changes on X-ray, CT, and obvious changes on bone scan and MRI. Stage III: pain is more severe, there is pain at rest, there can be functional limitation, there are changes such as bone trabecular fracture and bone cortical discontinuity or appearance on X-ray and CT, cystic-like changes, uneven density, etc. At this time, the femoral head has been fractured, but the shape is not changed much. In stage IV, there is severe pain and functional impairment, and the femoral head is deformed with gap changes on X-ray and CT or with hip joint deformation.
Clinical manifestations
1.Symptoms
(1) Pain The earliest symptom is pain in the hip or knee joint. The pain may be continuous or intermittent. Gradually or suddenly, there is pain, dull pain or soreness and discomfort in the hip or knee, often radiating to the inguinal region or the posterior or lateral side of the hip, or the medial side of the knee, and there is numbness in this region. It can be temporarily relieved after conservative treatment, but will come back after a period of time. The primary disease varies greatly in time from the onset of pain.
(2) Joint stiffness and limitation of movement In the early stage, patients have normal or slight loss of hip movement, which is manifested as impaired movement in a certain direction, especially internal rotation. In the late stage, due to hypertrophy and contracture of the joint capsule, the movement of the hip joint in all directions is severely restricted, the hip joint fuses and hip joint stiffness appears.
(3) Claudication Early patients may have intermittent claudication due to increased pressure in the femoral head, which improves after resting, while late patients may have persistent claudication due to femoral head collapse and hip subluxation. Patients with osteoarthritis often have claudication due to pain and morning stiffness, and claudication is aggravated in the late stage due to flexion, external rotation and internal deformity.
2.Signs
Local deep pressure pain, pressure pain at the stop of the adductor muscle, and positive axial percussion pain in some patients. In the early stage, the hip joint pain, Thomas’ sign and 4-character test are positive; in the late stage, the femoral head collapse, hip dislocation, Allis’ sign and single leg independence test are positive. Other signs include limited abduction, external rotation or internal rotation, shortening of the affected limb, muscle atrophy, and even signs of subluxation.
Laboratory and other ancillary tests
1.X-ray examination X-ray film can observe and study the morphology of joint surface, joint space and bone structure, but it does not show any imaging changes before the bone repair begins, so it is not significant for early diagnosis.
2, CT examination CT imaging has a higher resolution of the tissue, CT scan shows proliferation, sclerosis, fragmentation and cystic changes in the osteonecrosis area, which is clearer than conventional X-rays and can be more localized, so it has a guiding significance for the treatment hair program.
However, CT also has to wait for the density of bone tissue on X-ray to change before a diagnosis can be made, and at the same time, the overall situation of the hip joint and acetabulum is not sufficiently observed. Therefore, CT examination is not applicable to the early diagnosis of femoral head necrosis.
MRI is the most sensitive and accurate method to diagnose early ischemic necrosis of the femoral head because of its high soft tissue discriminatory ability. In the late stage of osteonecrosis can provide in anatomical changes, MRI has its unique superiority.
4. Radionuclide imaging
In the early stage of ischemic necrosis of the femoral head, the local blood supply and metabolism are low, the uptake of radionuclide by the affected femoral head is reduced, and the affected head/healthy head ratio is decreased. The severity of the ischemic necrosis can be determined by the magnitude of the decrease in the affected head/healthy head ratio. Nuclear bone scan can show the lesion when the blood supply to the femoral head is reduced without early clinical symptoms.
5.Digital Subtraction Angiography (DSA) can clearly show the blood supply of the arteries in the upper and lower femoral head, providing a good and precise indication for the choice of surgery and treatment.
Diagnostic basis
1.History History of trauma, hormone consumption, alcoholism, rheumatism, decompression work, etc.
2.Signs and symptoms There are hip pain, limited activity, limp; inguinal midpoint pressure pain, Thomas sign, 4-character test positive, the affected limb can be shortened, muscle atrophy, and even signs of subluxation.
3.Auxiliary examination X-ray film suggests ischemic necrosis of the femoral head.
4.For highly suspected ischemic necrosis of the femoral head, CT or MRI examination should be performed if there is no necrotic change on X-ray.
How to observe the destruction of the cartilage surface of the hip joint
With the development of ischemic necrosis of the femoral head, it is difficult to avoid the destruction of the articular cartilage surface of the femoral head by fragmentation and exfoliation and the cartilage surface of the acetabulum, and the damage of the articular cartilage surface determines the choice of treatment and the prognosis. We are currently trying to observe the condition of the cartilage surfaces of the hip joint through arthroscopic techniques to determine further therapeutic measures.
How to manage necrotic bone lesions in the femoral head
How to deal with the dead bone in the necrotic femoral head is a very difficult problem for clinicians. In fact, once necrosis of the femoral head has occurred, repair of the necrotic bone also begins to occur. However, how can we promote the repair of necrotic bone and the generation of new bone as soon as possible? The method was to remove all the necrotic bone from the femoral head and implant iliac bone, cancellous bone, etc. However, due to the insufficient mechanical strength of cancellous bone in the process of osteogenesis, secondary collapse occurred in the end, and later it was replaced by implanting suture bone flap with myotome or greater trochanter bone flap with vascular tip, and adding fibula bone flap and iliac bone flap, cancellous bone and BMP, etc. However, regardless of the method, the patient will not be able to have the flap implanted. However, no matter which method is used, patients need months or even years of bed rest and avoid weight-bearing on the affected limb, and such a long rehabilitation process is bound to have a serious negative impact on the life and work of young patients. How to promote the repair and reconstruction of the necrotic area and shorten the healing process is the serious challenge we face.
How to deal with the collapsed femoral head
Once the femoral head is deformed, osteoarthritis of the hip joint will inevitably occur. Therefore, in the treatment of femoral head necrosis, attention must be paid to prevent or correct the collapse of the femoral head. If the femoral head has not collapsed yet, but the density of the upper side of the femoral head is reduced or crescentic, the patient should avoid weight-bearing and wait until the density of the outer side of the femoral head is gradually increased and uniform before going down. For those whose femoral head has collapsed, surgical methods should be used to restore the shape of the femoral head as much as possible by using bone flaps and musculoskeletal flaps to jack up the collapsed area, so as to ensure the long-term efficacy of the treatment of femoral head necrosis and reduce the occurrence of osteoarthritis, but the destruction of the cartilage surface of the femoral head is still difficult to repair.
How to correct the ischemic state of femoral head necrosis
Although there are many theories on the pathological mechanism of femoral head necrosis. However, regardless of the cause, ischemia of the femoral head is the basic pathology of femoral head necrosis. After the femoral head is in an ischemic state, the normal metabolism and function of bone cells and bone tissue will be affected and necrosis will occur. Vascular implantation was studied as early as the 1960s to promote bone growth and repair, but later it was found that the blood supply from larger arteries was not good.
In recent years, the main purpose of Chinese and Western drug interventions for the treatment of femoral head necrosis is to improve the ischemic state of the femoral head and to promote the revascularization of the femoral head. Correcting the ischemic state of the femoral head is the primary problem in the treatment of femoral head, but how to observe the small vascular bundles implanted during and after surgery to prevent their embolization should have more intuitive and effective detection and treatment means.
Hyperbaric oxygen therapy
The patient inhaled pure oxygen with a mask in a hyperbaric chamber at 2 to 2.4 atmospheres for 20*3 minutes/day, 6 times a week, for a total of 100 treatments. 81% of patients with stage I femoral head ischemic necrosis recovered normal MRI after hyperbaric oxygen therapy, while only 17% of patients without hyperbaric oxygen therapy recovered, thus it is believed that hyperbaric oxygen can effectively treat stage I femoral head ischemic necrosis. It is also useful for all other stages of femoral head necrosis. Hyperbaric oxygen can rapidly increase blood oxygen partial pressure and tissue oxygen partial pressure, which is beneficial to tissue repair and healing; the local vasoconstrictive effect of hyperbaric oxygen and the increase of tissue oxygen partial pressure can help reduce edema of diseased tissues, lower intraosseous pressure, restore venous return and improve microcirculation; hyperbaric oxygen can enhance the deformability of red blood cells, inhibit blood coagulation system and platelet activation, and reduce blood viscosity. These effects help to arrest or reverse the process of ischemic necrosis of the femoral head and promote recovery. Therefore, hyperbaric oxygen therapy is a non-invasive treatment, and combined with other non-surgical treatments or surgical treatments is one of the best options for treating early ischemic necrosis of the femoral head, and hyperbaric oxygen is a more ideal treatment for femoral head necrosis
How to prevent secondary osteonecrosis of the femoral head
Although the treatment of osteonecrosis of the femoral head is very rich, it is still an incurable disease so far, and there is no effective preventive measure for idiopathic osteonecrosis of the femoral head. Therefore, early diagnosis is the key to delaying or stopping the development of osteonecrosis. Reasonable treatment methods should be adopted for the primary diseases that may cause secondary necrosis of the femoral head, such as femoral head fracture, femoral neck fracture and femoral intertrochanteric fracture, which should be treated with less trauma and reliable fixation, to avoid the hematological destruction of the femoral head of medical origin; treatment of hip dislocation and acetabular fracture, avoiding early weight-bearing of the affected limb should be given sufficient attention. After organ transplantation, rheumatoid arthritis, systemic lupus erythematosus, certain skin and eye diseases that require immunosuppressive drugs should be weighed comprehensively, and the possibility of causing femoral head necrosis should be fully considered when using the drugs.
At present, there are two categories of treatment methods for femoral head necrosis: non-surgical and surgical. Non-surgical treatments include bed rest, avoidance of weight-bearing devices for the affected limbs, hyperbaric oxygen therapy, electrical stimulation therapy, internal and external application of Chinese medicine and interventional therapy, etc. Surgical methods to preserve the femoral head include medullary decompression, free bone grafting, inter-rotor osteotomy, bone flap transplantation with myotomal or vascular tissues, etc.; surgical methods to preserve the hip joint include Artificial prosthesis replacement, of which there are femoral head surface replacement, artificial femoral head replacement, total hip replacement and hip fusion.
For patients with femoral head necrosis up to Ficat late stage III, especially for children with femoral head necrosis, we use internal and external methods, and according to the evidence, we apply the methods of tonifying the kidney and benefiting the marrow, removing dampness and phlegm, activating blood circulation and removing blood stasis, and combine with stent protection and avoiding weight-bearing on the affected limb, and other comprehensive methods are effective in reducing the pain of the affected hip and delaying the further development of necrosis.
For lesions with necrosis reaching Ficat late stage III or later, the efficacy of using necrotic lesion removal, free bone graft filling or bone flap transplantation with myotomal or vascular tissues still needs further observation and research. Although postoperative hip pain was relieved, further development of femoral head necrosis existed in most cases, and we speculate that the reduction of postoperative hip pain may be due to the destruction of the nerve branches of the hip joint or the reduction of intramedullary pressure.
In the past, hip fusion was mainly used for young patients who needed heavy physical labor, but because of the serious impact on work and life after surgery, some patients strongly requested another surgery for artificial joint replacement. However, due to the destruction of the hip muscle groups or disuse atrophy, the function of the joint after the arthroplasty is significantly worse than that of the non-fused artificial joint.
Active and rational treatment of the primary disease is the key to prevent secondary femoral head necrosis. Due to the interdisciplinary treatment of rheumatoid arthritis, gout and many other diseases, non-specialists are keen to apply hormones in large quantities for a long time to obtain pain relief, failing to consider the consequences of secondary necrosis of the femoral head, and such cases are not uncommon in clinical practice. Once the artificial joint replacement is received, Chinese herbal medicine is used to replace hormone treatment for the primary disease to prevent necrosis of the femoral head on the healthy side. In osteoporotic patients, anti-inflammatory pain is not used to prevent heterotopic bone substitution to delay the revision surgery.
The prognosis and regression of this disease are closely related to the extent of ischemic necrosis of the femoral head, whether there is femoral head collapse and the degree of collapse, and the time the patient receives treatment. For ischemic necrosis of the femoral head in Ficat stage I and II, the recent results are satisfactory after combined Chinese and Western medicine treatment; patients with Ficat stage III or above have a tendency to develop further because the femoral head has collapsed, especially for patients with alcoholic femoral head necrosis and obese body shape, the prognosis is mostly poor.