A fracture between the lower femoral head and the base of the femoral neck is called a femoral neck fracture and is one of the most common fractures in the elderly. It is especially common in elderly women.
Symptoms
1.Deformity: The affected limb has mild hip flexion and knee flexion and external rotation deformity.
2. Pain: In addition to spontaneous pain in the hip, pain is more obvious when moving the affected limb. Pain is also felt in the hip when the affected limb is knocked at the heel or the large ridge. There is often pressure pain below the midpoint of the inguinal ligament.
3. Swelling: Femoral neck fractures are mostly intracapsular fractures with little bleeding after the fracture and surrounded by the joint capsule and abundant muscle groups, therefore, local swelling is not easily visible in appearance.
4. Functional impairment: Patients with displaced fractures are unable to sit up or stand after the injury. However, there are some patients with nondisplaced linear fractures or insertion fractures who can still walk or ride a bicycle after the injury. Special attention should be paid to these patients so that a stable fracture without displacement does not become an unstable fracture with displacement due to missed diagnosis. There are still many such cases in clinical practice.
5. Shortening of the affected limb: In displaced fractures, the distal segment is displaced upward by muscle traction, and thus the affected limb becomes shorter.
Pathology
There are two basic factors for fractures to occur in adult elderly, one is the decrease of bone strength, and the other is the degeneration of the periprosthetic muscle groups in the elderly, which cannot effectively counteract the harmful stresses in the hip. Fractures of the femoral neck in young adults, on the other hand, are often due to severe injuries.
Clinical diagnosis
History of obvious trauma, pain in the affected limb, and limitation of movement. Х radiographs can determine the fracture site and displacement. Fracture of the neck of the femur does not heal clinically and is characterized by pain in the affected area, weakness of the affected limb and fear of weight bearing. On the X-ray, the following manifestations are observed.
(1) The fracture line is clearly visible.
(2) Cystic changes in the bone on both sides of the fracture line.
(3) In some patients, although the fracture line is not visible, the femoral neck continues to resorb and shorten during successive photographs, so that the triple-winged nail protrudes inward into the acetabulum or withdraws caudally outward.
(4) Gradual dislocation of the femoral head and gradual increase in the inward inclination of the femoral neck.
In patients who have been found to have non-union, the fracture may still heal after appropriate protection and treatment, such as limb weight-bearing restriction and reduction of limb activity.
The functional recovery of femoral neck fractures is not as good as other fractures. Generally speaking, only about half (50%) of the patients are able to achieve satisfactory functional recovery despite proper treatment, such as easy walking, no pain, and comfortable squatting. About 15% of diseased fractures do not heal. About 20-35% of patients develop necrosis of the femoral head. Some patients also develop traumatic arthritic changes of the hip joint after the injury.
Treatment
Before choosing the treatment, first of all, we should understand the general condition of the injured person, especially the elderly should pay attention to the comprehensive examination, blood pressure, heart, lung, liver, kidney and other major organ functions, combined with fracture comprehensive consideration.
Femoral neck fractures heal slowly, taking 5-6 months on average, and the fracture non-healing rate is high, averaging about 15%. Factors affecting fracture healing are related to age, fracture site, fracture type, degree of fracture and displacement, quality of repositioning, and the strength of internal fixation.
General treatment methods.
1.External fixation: Applicable to abductor and intermediate type fracture, generally most of the affected limb traction or anti-foot external rotation shoes are used for 8-12 weeks to prevent the affected limb from external rotation and internal rotation, which takes about 3-4 months to heal and rarely occurs non-healing or femoral head necrosis. However, there is a possibility of dislocation of the fracture in the early stage, so some people advocate the use of internal fixation as appropriate. As for external fixation in plaster, it is rarely used and limited to smaller children. Internal fixation is the most widely used indication. It is suitable for most of the internal fractures. Generally, it takes about 4-6 months to heal, and the fracture should continue to be observed until five years after surgery to facilitate early detection of ischemic necrosis of the femoral head.
2.Internal fixation: At present, hospitals with conditions adopt closed reduction internal fixation with the cooperation of TV X-ray machine, or open reduction internal fixation if there is no X-ray machine equipment. Before internal fixation, the fracture is repositioned manually, and then internal fixation is performed after confirming the anatomical repositioning of the fracture end. There are many forms of internal fixation, which are summarized in the following types.
(1) Smith-Petersen triple-edged nail internal fixation: Since 1929, when Smith-Petersen first created the use of triple-edged nail, the efficacy of femoral neck fracture has been significantly improved, and it is still one of the commonly used internal fixation methods.
(2) Sliding internal fixation: various types of compression nails or pins are available. The compression nail or pin can slide inside the sleeve, and when there is absorption on both sides of the fracture line, the nail slides inside the sleeve to shorten in order to keep the fracture end in close contact, and the early weight-bearing is more conducive to the insertion of the fracture end.
(3) Compression internal fixation: this kind of internal fixation with compression device can make the fracture ends embedded with each other to facilitate healing. Commonly used are Charnley’s compression screw with spring and Siffert’s Corkscrew Bolt.
(4) Multi-pin (or nail) internal fixation: 2-4 screws or steel nails are inserted respectively according to the bone structure and biomechanical principles of the upper end of the femur, which not only fixes firmly, but also reduces the damage to the femoral head. Such as Moore or Hagia pins, etc. In short, there are various forms of internal fixation.
3.Bone grafting at the same time of internal fixation: For difficult healing or old fracture, in order to promote its healing, bone grafting at the same time of internal fixation, there are two methods of bone grafting.
(1) Free bone grafting: such as taking fibula or tibia and inserting it into the femoral head under the greater trochanter, or filling the bone defect with cancellous bone, etc.
(2) Bone graft with tip: the more commonly used one is suturing muscle tip bone flap bone graft. With the progress of microsurgery technology, bone grafting with vascular tip has been carried out. For example, bone grafting of deep iliac artery flap.
4.Osteotomy: For more difficult healing or some old fractures, osteotomy can be performed selectively, such as inter-rotor osteotomy or sub-rotor osteotomy. Osteotomy has the advantages of easy operation, less shortening of the affected limb, and is conducive to fracture healing and functional recovery.
5.Arthroplasty: It is suitable for subtrochanteric femoral neck fractures in the elderly. For old femoral neck fracture, fracture does not heal, or ischemic necrosis of femoral head, if the lesion is limited to the head or neck, femoral head replacement is feasible, if the lesion has damaged the acetabulum, total hip replacement is needed. At present, the less common types of artificial hip joints are cobalt alloy pearl surface artificial femoral head, nitrogen injected titanium alloy microporous surface artificial femoral head, double-action central locking ring type artificial femoral head, etc. The acetabular damage is replaced by polymer polyethylene artificial molar, and the clinical application has achieved better results.