With the improvement of living standards, people are becoming more and more concerned about their health problems. Among them, osteonecrosis of the femoral head is valued by the general public because of its increasing incidence year by year and its serious impact on patients’ walking ability. So, do you know about osteonecrosis of the femur? Do you know how to prevent and treat osteonecrosis of the femur in daily life?
First, what is osteonecrosis of the femur?
Osteonecrosis of the femoral head (ONFH), also known as ischemic necrosis of the femoral head, is a common and intractable disease in the field of orthopedics. 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.
Why is the femoral head susceptible to necrosis?
Osteonecrosis can occur in any part of the human skeleton, and the highest incidence of femoral head necrosis is mainly determined by biomechanical and anatomical characteristics.
Biomechanical factors
1. Heavy load. The hip joint is the largest joint in the human body, supporting the weight of the entire trunk, maintaining this large pressure for a long time, not only easy to cause structural damage, but also affect the local blood circulation.
2.Shear force. The hip joint is different from other weight-bearing joints as the two bone ends of the joint force line vertical, the femoral stem and femoral head neck between the formation of 132 degrees of the angle, the gravity of the trunk is from the acetabulum through the head of the femur, neck migration to the femoral stem, the force line is not vertical, the physiological pressure on the head and neck is much greater than other joints.
3.Large range of motion. The range of motion of the hip joint is second only to the shoulder joint, extension, adduction, abduction, rotation, etc. It can complete each axial movement, and there are more chances of injury.
Anatomical factors
An important reason for the prevalence of femoral head necrosis is its special anatomical structure. The blood supply of the femoral head mainly relies on the lateral supporting band and the medial supporting band arteries issued from the arterial ring outside the hip capsule, and the number of anastomosing branches of the vessels is small and weak. Femoral head side branch circulation is small, easy to damage and make the subchondral osteonecrosis.
Third, what are the causes of femoral head necrosis?
The causes of femoral head necrosis are diverse (about 60 kinds), complex, difficult to classify comprehensively and systematically, which is related to the pathogenesis is unclear, in the long-term theoretical research and clinical diagnosis and treatment of several common pathogenic factors, although the cause is different, but its common pathological manifestations is the femoral head ischemia, more consistent recognized theory is the blood supply is blocked.
Trauma leading to femoral head necrosis (30%).
Such as femoral neck fracture caused by external impact, hip dislocation, hip sprain and contusion, etc. Trauma is the main factor causing femoral head necrosis, but the occurrence and extent of traumatic femoral head ischemic necrosis mainly depends on the degree of vascular destruction and the compensatory ability of collateral circulation. The blood supply of the femoral head is supplied through an arterial ring at the base of the femoral neck. Fractures of the femoral neck inevitably lead to vascular damage, which has a 60-70% chance of leading to femoral head necrosis.
Medications cause femoral head necrosis (25%).
Such as bronchitis, asthma, rheumatism, rheumatoid, neck, shoulder, back and leg pain, diabetes, skin disorders, and long-term use of hormonal drugs, due to the massive or long-term use of hormones, is one of the reasons for the occurrence of femoral head necrosis, hormonal femoral head necrosis bilateral simultaneous onset is common, and more than half of all patients first one side of the onset, after several months or years, the other just onset, clinical manifestations of hip pain, swelling, swelling, and lower limb function is limited. The clinical manifestations are hip pain, swelling, chest tightness, limited function of lower limbs, etc.
Alcohol stimulation leads to femoral head necrosis (18%).
Chronic alcoholism is an important factor, due to the accumulation of alcohol in the body as a result of long-term heavy drinking, resulting in increased blood lipids and damage to liver function, elevated blood lipids, resulting in increased blood viscosity, slowing blood flow, causing changes in blood coagulation, thus blocking blood vessels, bleeding or fat embolism, resulting in osteonecrosis, which is clinically aggravated after drinking. The occurrence of femoral head necrosis is related to the individual alcohol metabolic rate.
Fourth, what is the performance of femoral head necrosis?
In the early stage, there can be no clinical symptoms, and usually the necrosis of the femoral head can be detected by MRI. Therefore, MRI is the most sensitive and accurate examination method to diagnose femoral head necrosis.
Clinical symptoms gradually appear in the later stage.
1. Pain
At the earliest appearance, the pain in the hip or knee joint is continuous or intermittent, gradually worsens, and even affects sleep in severe cases. The most obvious part is the root of the thigh.
2.Limited activity
Early normal or mildly restricted, the first to appear is the limitation of internal rotation.
3.Crippling
Intermittent claudication may occur in the early stage, which improves after rest, and persistent claudication in the late stage.
4.Signs
Local deep pressure pain: typical sites are the midpoint of the inguinal region and the stopping point of the adductor muscle.
Percussion pain: greater trochanteric percussion pain and longitudinal percussion pain.
Positive Thomas sign: the patient was lying on his back, and when the patient’s lower limbs were flattened on the examination table, the presence of anterior lumbar protrusion was positive. The patient was also made to hold the lower limbs of one side of the flexed knee with both hands, at which time the lumbar spine could be attached to the examination table, and the lower limbs of the opposite side could not be flattened, indicating a lesion on this side.
Positive “4” test: “4” test operation method: the patient lies on his back, one lower limb straight, the other lower limb in the shape of “4” placed at the knee joint near the straightened lower limb, and one hand Press the knee joint with one hand and press the iliac crest on the opposite side with the other hand, and press down simultaneously with both hands. When the pressure is applied, the sacroiliac joint appears to be painful and the knee joint on the bending side cannot touch the bed is considered positive.