Subtrochanteric fracture of femur

Introduction to subtrochanteric fractures of the femur Subtrochanteric fracture of the femur refers to the fracture from the femoral trochanter to the junction between the middle and proximal femoral shaft, the narrowest part of the bone marrow cavity. The incidence is 10% to 34% of hip fractures. There are 2 groups of age groups, 20 to 40 years old and over 60 years old. Older group fractures are mostly caused by low-energy trauma, and younger group fractures are mostly caused by high-energy injuries, often combined with other fractures and injuries. The mortality of the subtrochanteric fractures of the femur has been reported by the authors ranging from 8.3% to 20.9%. Due to the distribution of physiological stress under the femoral trochanter, the surgical treatment has higher fracture nonunion and internal fixation loss rate. After the fracture occurs, the femoral shaft is shortened under the tension of the muscle, and the external rotation is deformed, and the femoral head and neck are outside. Exhibition, posterior tilt, therefore, the treatment of femoral subtrochanteric fractures is to correct the adduction of the femoral shaft, shortening, external rotation and femoral head and neck abduction and backward tilt, external rotation, restore the tension of the hip adductor muscle, Thereby restoring limb function. Therefore, the understanding of the biomechanical characteristics of the lower part of the femoral trochanter, the analysis of the fracture type, and the application of various types of internal fixation and the recognition of indications will directly affect the treatment effect. basic knowledge Sickness ratio: 0.05% Susceptible people: good for people aged 20 to 40 and over 60 Mode of infection: non-infectious Complications: fracture

Causes of subtrochanteric fractures

(1) Causes of the disease

Often caused by direct violence.

(two) pathogenesis

Simple subtrochanteric fractures are more common in young people, mostly caused by large direct violence. Many cases of fractures are comminuted, and subtrochanteric fractures associated with intertrochanteric fractures can occur in elderly patients with osteoporosis. Caused by a lighter trauma such as falling.

After the subtrochanteric fracture, the proximal end is flexed by the gluteal muscle, the iliopsoas and the external rotator, and the abduction, external rotation, and the distal end are affected by the adductor muscles and the lower limbs. Move inwards and shift backwards.

Prevention of subtrochanteric fracture of the femur

There is no effective preventive measure for this disease. Early detection and early diagnosis are the key to the prevention and treatment of this disease.

Complications of subtrochanteric fractures Complications

Hip inversion

Hip varus is the most common complication of subtrochanteric fracture. The root cause is that the abductor muscle is pulled at the distal end of the femur, and the insertion point of the inserted medullary needle is not correct. The prevention is the first accurate insertion of the medullary needle. Due to the proximal flexion, abduction, and external rotation of the fracture, it is difficult to accurately select the piriform fossa incision, and the opening of the femoral anatomical axis must be confirmed in the C-arm observation of the positive lateral plane. There are 2 ways to To reduce this difficulty, one is to receive the trunk, the second is to insert the proximal end of the fracture in the femoral neck, and the second reason is the incomplete structure of the medial femoral cortex. If it is open reduction, it must be reconstructed. The medial femoral integrity, indirect reduction, intraoperative attention to measure the anterior superior iliac spine to the first and second toes through the midpoint of the humerus, it is generally considered that <10 ° hip varus is acceptable, if the hip is inverted Large angle, you can perform osteotomy.

2. Fracture does not heal

The cause of nonunion of the fracture is internal fixation failure and fracture. There are three cases of internal fixation fracture and failure:

(1) proximal locking nail mis-locking: especially in the posterolateral femoral fracture, the proximal end of the fracture is displaced forward, and the proximal locking nail will enter the femoral head from the posterior side of the femoral neck. This locking should be avoided. The correct placement of the end lock nail requires the locking nail to be placed at the position of the femoral head under fluoroscopy. The proximal proximal locking pin should be located in the lower third of the femoral head, and the lateral position is at the center. Our experience is when the femoral head is locked, if In the positive side, 2 screws are not parallel, there must be 1 lock pin mislock, should be carefully checked and corrected.

(2) When the medullary needle is motorized, it is not locked: it can prevent the rotation and shortening of the limb. The fracture does not heal and remove the distal locking nail. Especially in osteoporosis, the proximal locking nail stress is inevitable, and the result is to the proximal locking. The nail fracture causes the fracture to not heal, so the motorization is not advocated before the fracture is healed. The distal locking nail can be taken before the intramedullary nail is taken after the fracture is healed, so as to improve the quality of the callus.

(3) Intramedullary nail rupture: the intramedullary nail fracture occurs mostly at the proximal keyhole and at the fracture line. The reason is that before the fracture is not healed, there is no regular review. The patient is completely weight-bearing in the early stage, and the fracture nonunion treatment should be re-fixed and Bone grafting.

Femoral subtrochanteric fracture symptoms Common symptoms Comminuted fractures Joint swelling Shock residual fracture

a local pain after injury, swelling, acute limb adduction, short deformity, local bleeding, often accompanied by hemorrhagic shock, due to strong external force, should pay attention to multiple injuries and combined injuries.

1. Seinsheimer classification

Seinsheimer is divided into 5 types based on the number of fracture blocks, the location and the shape of the fracture line.

Type I: no displacement or displacement of the fracture <2mm.

Type II: fracture displacement is two fracture blocks, divided into 3 subtypes, IIA small trochanteric transverse fracture; IIB spiral fracture, small trochanter in proximal fracture, IIC spiral fracture, small trochanter on the far side Fracture block.

Type III: There are 3 fracture blocks, in addition to the subtrochanteric fracture, IIIA, there is still a small trochanteric fracture, and IIIB has a butterfly fracture in the middle of the subtrochanteric fracture.

Type IV: comminuted fracture with 4 fracture blocks or more.

Type V: subtrochanteric fracture with intertrochanteric fracture.

2.Russell and Taylor classification

Russell and Taylor extend backward according to the continuity of the small trochanter and the fracture line to the large trochanter involving the piriform fossa. These two factors affect the treatment and propose one type:

Type I: The fracture line is not postponed to the piriform fossa. In the IA type fracture, the fracture and fracture line are extended from the small trochanter to the femoral isthmus area. This area can have various degrees of crushed bone, including bilateral cortical bone. Fragments; multiple fracture lines and fragments of type IB fractures are included in the small trochanter to the narrow region.

Type II fracture, the fracture line extends proximally to the large trochanter and piriform fossa, type IIA fracture, extending from the small trochanter through the femoral isthmus to the piriform fossa, but the small trochanter has no severe crushing or larger fracture block The IIB fracture line extends to the piriform fossa, and the medial cortex of the femur is comminuted, and the continuity of the small trochanter is lost.

Examination of subtrochanteric fractures

X-ray examination can confirm the diagnosis.

Diagnosis and diagnosis of subtrochanteric fractures of the femur

History of trauma, local pain and swelling after injury, with injured limb adduction, shortening deformity, more bleeding in the fracture, need to prevent hemorrhagic shock, greater traumatic violence, should pay attention to check for multiple trauma, X-ray examination That can confirm the diagnosis.

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