There are many causes of claudication, such as unequal length of both lower limbs, functional limitation of hip, knee and ankle joints, tilt of the pelvis, deformity of the spine, muscle spasm or weakness, pain, psychological factors, etc. The main causes of claudication in patients with femoral head necrosis are pain and functional limitation, and shortening of the affected limbs. If the femoral head collapses and causes shortening of the affected limb, the ipsilateral pelvis drops when the leg lands, causing the ipsilateral shoulder to tilt and sink, and the opposite swing leg has excessive hip and knee flexion with increased ankle dorsiflexion, resulting in a sloping shoulder step.
The affected leg is often in a pain-proof gait, and the affected foot is lifted as soon as it hits the ground, while the healthy foot lands heavily and for a long time. The functional limitation is mainly manifested by the internal retraction of the affected hip, and the knee joint on the affected side will be tightly close to the healthy side, and even the two inner knees rub against each other.
What are the factors that lead to femoral head necrosis?
1. Long-term alcohol consumption, usually with a history of 5-10 years of alcohol consumption;
2, long-term history of hormone use, such as chronic nephritis, lupus erythematosus, scleroderma, etc. need to take hormones, there is also the abuse of hormones, etc.;
3, history of trauma, such as femoral neck fracture, hip dislocation, femoral head fracture, etc. The younger the patient with femoral neck fracture, the greater the chance of postoperative complications of osteonecrosis of the femoral head;
Why is osteonecrosis likely to occur in the femoral head?
Osteonecrosis can occur in any part of the body, and more than 40 cases of ischemic necrosis have been identified, which are related to biomechanical and anatomical characteristics. Because the femoral head is the terminal blood vessels are fan-shaped 20~25 branches, forming an arterial and venous ring at the junction of the head and neck, which originates from the internal and external spinous femoral artery.
1.Heavy load
The hip joint is the largest joint in the human body, supporting the weight of the entire trunk, the pressure between the head and the socket is bound to increase, maintaining this large pressure for a long time, which not only easily causes structural damage, but also affects the local blood flow circulation.
2.High 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 the femoral head neck between the formation of 132 ° angle, the gravity of the trunk is from the acetabulum through the femoral head, neck migration to the femoral stem, the force line is not vertical, the formation of shear force. Therefore, the physiological pressure on the head and neck is much greater than that on 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.
4.Low blood supply
The blood supply of the femoral head mainly relies on the lateral support band and the medial support band arteries issued by the extracapsular arterial ring. The amount of anastomosing branches of the vessels is small and weak, and when one vessel is blocked and the other cannot compensate in time, it will cause the impaired blood supply to the femoral head.
Why does femoral head necrosis mostly occur on the anterolateral side?
After femoral head necrosis, bone fragmentation, collapse and flattening of the head shape are often seen, which are common phenomena of necrosis. Through the observation of a large number of clinical cases, it is found that most of the femoral head necrosis begins to occur in the anterolateral side, which is mainly due to the gravitational concentration.
A large number of clinical facts prove that stress concentration can fracture the trabeculae under the cartilage, which can compress the bone and increase the compressive stress in the bone marrow, eventually leading to osteonecrosis. Most of the patients we have seen with old unconnected femoral neck fractures have kept their femoral head round and not collapsed. Below the outer edge of the acetabulum, which is on the outside of the femoral head, is the main part of the femoral head that bears weight and is therefore susceptible to necrosis.
What are the clinical manifestations of ischemic necrosis of the femoral head?
The disease has a slow onset and a long course, and there may be no obvious symptoms at the beginning of the disease. The most common early symptom is mild pain in the hip, especially after exertion or walking for a long time, and the pain often radiates to the groin area or the posterior and lateral hip or medial knee. With the aggravation of claudication and hip pain, the affected hip shows mild flexion, adduction deformity, abduction and limitation of internal rotation activities. The symptoms may continue to worsen and manifest as osteoarthritis symptoms in the late stage.
What are the exercise precautions for patients with femoral head necrosis?
1, necrosis of the femoral head needs to be bedridden, to carry out functional exercises of the upper limbs, with the aid of pullers and other equipment, while paying attention to the activities of the knee and ankle joints and the hip joint on the healthy side.
2, in the process of activity, prevent falls, because the hip joint movement of femoral head necrosis is limited, the bone is fragile, so the reaction ability is reduced, easy to fracture, it is best to have someone to take care of when outdoor activities.
3, in the middle and late stages of femoral head necrosis, the hip joint activity is more severely restricted, but also insist on walking with crutches, if you can’t walk with crutches, you can take a wheelchair vehicle for outdoor activities.
4, the early stage of femoral head necrosis can walk with the help of crutches, bilateral femoral head necrosis walking with the help of crutches, can be developed according to the condition of the morning and evening walking distance. If the condition allows, good physical condition, you can ride a bicycle or tricycle.
Since these manifestations are not only seen in ischemic necrosis of the femoral head, they are easily confused with other diseases such as lumbar disc herniation and ankylosing spondylitis, so you should go to a specialist hospital to find a doctor to confirm the diagnosis.