Definition: 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 common fractures in the elderly. It is especially common in elderly women.
Fracture type and displacement
According to the relationship between the two ends of the fracture are classified as
Adductor type, the femoral head is abducted, the upper part of the fracture is embedded, the head and neck are in an abductor relationship, the femoral head is not displaced and rotated in the lateral view, also called embedded type, the most stable.
intermediate type, the X-ray orthopantomograph is the same as the abductor type, while the lateral view shows the femoral head posteriorly tilted and a cleft in front of the fracture line, which is actually the intermediate stage of transition to the involutor type.
The inversion type, where the two fracture ends are completely misaligned, is also known as the dislocation type.
The fracture site is divided into.
Subcranial type, where all fracture surfaces are located at the craniocervical junction and the proximal end of the fracture is not carried to the neck, which is less common.
The cephalocervical type, in which the outer upper part of the fracture surface passes under the head and the inner lower part carries part of the medial cervical cortex in a beak shape, is the most common type.
The transcervical type, in which the fracture surface passes completely through the neck, is rare and is thought to be almost nonexistent in elderly patients.
The basal type, in which the fracture surface is close to the inter-rotor line. The subcranial, craniocervical, and transcranial types are intracapsular fractures; the basal type is extracapsular and should be included in the trochanteric fracture because it has good healing and is different in nature from the intracapsular fracture.
Pauwels’ classification
Pauwels’ classification: According to the angle between the fracture line and the vertical line of the femoral stem, the fracture is classified as Type I, <30°; Type II, 30°-50°, >50°. The greater the inclination of the fracture line, the more unstable it is. If the angle is less than 30°, the fracture surfaces are embedded in each other, the position is stable and easy to heal; if it is greater than 50°, the fracture is subjected to greater shear stress, the position is unstable and the prognosis is poor. However, the measurement of this angle should be accurately measured after the distal end of the fracture is placed in the internal rotation position and the anterior tilt angle is eliminated, so it is of little value before repositioning.
Garden classification
Garden’s classification: according to the degree of dislocation, it is divided into: type I, no dislocation; type II, mild dislocation; type III, head abduction, distal upward displacement and mild external rotation; type IV, distal upward displacement and external rotation obviously. Since the femoral neck bones in the elderly are osteoporotic and fragile and subject to higher stress, only a small external force of rotation is required to cause a fracture. Almost all femoral neck fractures in the elderly are caused by indirect violence, mainly external rotation, such as falls on flat ground or sudden twisting of lower limbs. In a small number of young adults, femoral neck fractures are caused by strong direct violence, such as a vehicle impact or a fall from a height, or even multiple injuries at the same time.
Symptoms
1.Deformity: the affected limb mostly has mild hip flexion and knee flexion and external rotation deformity
2.Pain: In addition to spontaneous pain in the hip, the 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 the traction of the muscle groups, thus shortening the affected limb.
The diagnosis can be made clearly by radiographs. In particular, the frontal and lateral radiographs of the sciatic hip joint can determine the type of fracture, its location, displacement and the choice of treatment.
Clinical diagnosis
A history of trauma, pain and limited movement of the affected limb is obvious. Х radiographs can determine the fracture site and displacement. Non-union of the femoral neck fracture is clinically manifested 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. There is also a proportion of patients with post-injury traumatic arthritic changes of the hip joint.
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 an average of 5-6 months, and the fracture non-healing rate is high, averaging about 15%. The 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 fractures, generally the affected limb is traction or anti-foot external rotation shoes for 8 to 12 weeks to prevent the affected limb from external rotation and internal rotation, which takes about 3 to 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 plaster fixation, it is rarely used and is 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 as follows: ①Smith-Petersen triple-edged nail internal fixation: Since 1929, when Smith-Petersen first created the 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. ②Sliding internal fixation: various types of compression nails or pins are available. The compression nail or pin can slide in the sleeve, and when there is absorption on both sides of the fracture line, the nail slides in 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. The commonly used ones are Charnley’s compression screw with spring and Siffert’s Corkscrew Bolt. ④Multi-pin (or nail) internal fixation: 2 to 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 securely 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 tibial strip and inserting it into the femoral head under the greater trochanter, or filling the bone defect with cancellous bone, etc. ② Bone grafting with tip: the more commonly used is suturing muscle tip bone flap bone grafting. 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 fractures, fractures that do not heal, or ischemic necrosis of the 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 required. At present, the commonly used types of artificial hip joints include cobalt alloy pearl surface artificial femoral head, nitrogen injected titanium alloy microporous surface artificial femoral head, double-action central locking ring artificial femoral head, etc. If the acetabulum is damaged, it can be replaced with high polymer polyethylene artificial molar, and the clinical application has achieved better results.
Conservative treatment
For fresh non-displaced stable abductor fractures, skin traction or thong shoes are used.
Complications
1. General complications of early and late orthopaedic surgery.
Including pelvic fracture, joint dislocation, internal organ injury, fracture elsewhere, hemorrhage, shock, etc.
2.Special complications.
Including non-union of femoral neck fracture, ischemic necrosis of femoral head, traumatic arthritis, etc.
The fracture may also damage these vessels, causing necrosis of the femoral head, or the fracture may not heal. The most common and serious complications are osteonecrosis and necrosis of the femoral head.
1. delayed healing and nonunion Fractures of the femoral neck that have not completely healed within 6 months after treatment should be diagnosed as delayed healing. The occurrence of bone non-union after femoral neck fracture is related to age, degree of fracture displacement, fracture line location and severity of osteoporosis, etc. Many patients can suffer from re-displacement as a result. According to the survival of the femoral head, we should choose to do bone flap grafting or arthroplasty with blood supply again, and those with head necrosis or existing displacement should do artificial joint replacement. 2, ischemic necrosis of the femoral head The fracture has healed, the femoral head necrosis has not been seriously deformed, the clinical symptoms are mild, there is no need to rush to surgery. They can maintain a normal life and prevent excessive weight bearing and exercise. Many patients can maintain a normal life and light work for many years after ischemic necrosis of the femoral head. Patients with symptoms of osteoarthritis can take herbal medicine or non-steroidal anti-inflammatory drugs. After the pain and dysfunction become significantly worse, total hip arthroplasty needs to be considered.