Femur intertrochanteric fractures have a high incidence in the elderly population, and most of them are comminuted fractures.Operation is the preferred clinical treatment, which can not only effectively treat, but also significantly reduce the complications caused by long-term bed rest. There are mainly two kinds of surgical treatment: extramedullary fixation and intramedullary fixation. And intramedullary fixation seems better.It is mainly reflected in the following aspects :(1) the arm of force is short, torque is small, and it’s biomechanically stable; (2) minimally invasive operation, small incision and less intraoperative blood loss; (3) the fracture end does not need to be exposed, causing less damage to the periosteum and soft tissues, which can make the fracture heal better. Therefore, intramedullary fixation is becoming the preferred method in the surgical treatment of intertrochanteric fractures.
Perioperative blood loss may lead to many complications and poor prognosis. It also increases the incidence of infection and deep vein thrombosis. The patient's mortality rate also increases. Therefore, in the treatment of intertrochanteric fractures, it is importent to find the causes of perioperative blood loss. Hidden blood loss accounts for a high percentage of total perioperative blood loss in patients with intertrochanteric fractures. If the presence of hidden blood loss is not paid attention to, it will often lead to anemia or low blood volume in patients, which will affect the postoperative recovery and even cause serious consequences. At present, the biological mechanism of hidden blood loss has not been clearly studied. And the existing researches believe that the causes of hidden blood loss mainly include the following aspects: 1) when the blood enters the tissue or the joint cavity, it no longer participates in the humoral circulation, 2) red blood cell hemolysis caused by injury. Some stress during the operation, such as trauma and anesthesia, may lead to changes of the blood internal environment, red blood cell peroxidation damage, red blood cell damage in the process of autologous blood transfusion and other factors may cause hemolysis, thus making the hidden blood loss more serious. 3) gastrointestinal stress ulcer caused by trauma and surgery will also cause the occurrence of hidden blood loss.
In this study, factors affecting perioperative hidden blood loss in patients with intertrochanteric fractures were analyzed. And it was found that unstable fractures, advanced age, osteoporosis and general anesthesia were independent risk factors for increasing hidden blood loss. The form and mechanism of fracture injury determine the degree of comminution and the degree of damage to the surrounding soft tissue. That is to say, it determines the type of fracture. Patients with different degrees of injury also have some differences in blood loss, which indicates that there is a certain correlation between the amount of hidden blood loss and the type of fracture. Some investigators found significant differences in mean hemoglobin decrease between patients with intra and extracapsular fractures. Kumar et al. also observed significant differences in the amount of hidden blood loss in patients with different fracture types. Some researchers found hidden blood loss of patients with Evans Ⅰ, Ⅱ type of fractures was significantly lower than Ⅲ, Ⅳ type. The results of this study showed that the hidden blood loss of patients with unstable fractures was significantly higher than patients with stable fractures. All the above studies have shown that there is a certain correlation between fracture type and hidden blood loss. So we should pay attention to the review of patients' blood routine and take timely blood transfusion during treatment.
The selection of anaesthesia, the use of anticoagulant drugs and the age are also key factors affecting the perioperative hidden blood loss. It has been reported that the amount of hidden blood loss is significantly higher in patients under general anesthesia than those under epidural anesthesia. This may be related to the fact that the antifibrinolysis ability of patients under general anesthesia is lower than that of patients under epidural anesthesia. During the treatment of lower limb surgery patients, a certain amount of anticoagulant drugs will be used in order to prevent the formation of venous thrombosis. So the amount of hidden blood loss will also increase. In patients with total hip replacement, researchers found that the amount of hidden blood loss in patients older than 70 was significantly higher than patients younger than 70. In this study, the amount of hidden blood loss was significantly higher in patients over 60 years old than in patients under 60 years. The reason may be that the older has a significant reduction in the function of cardiovascular system, blood vessels occur hyaline degeneration, and muscle atrophy. All of these factors can cause the decline in body's regulation ability. This makes the organization clearance fluid fail to supplement of blood circulation quickly. Finally, it increases the hidden loss of blood. The effect of gender on the amount of hidden blood loss is still controversial. Most researchers believe that there is no significant difference between male and female patients with intertrochanteric femur fracture. However, still some researchers believe that there are significant differences in the amount of hidden blood loss between different genders. The results of our study indicate that gender is not a risk factor for hidden blood loss, which is consistent with most reports.
At present, there are few reports on the effect of bone density on perioperative blood loss in patients with intertrochanteric fractures. In our study, there were significant differences in the amount of hidden blood loss between groups with different bone mineral density. This may because that for patients with low bone density, bone trabeculae become thin, and some even fracture. Osteoporosis may cause the enlargement of bone marrow space, the appearance of micropores and cancellation of bone cortex, and the enlargement of periosteal pores, cortical pores, and endosteum pores. As a result of the above changes, when the blood vessels are damaged after bone fracture, the blood entering the medullary cavity is more likely to flow into the surrounding tissues, resulting in local hematoma around the bone.Finally, it increases the amount of blood loss during the perioperative period. In addition, osteoporosis patients are generally older, the body's self-regulation ability is weakened, vascular elasticity is poor, which also increases the risk of hidden blood loss. In order to explore whether osteoporosis can lead to changes in hematopoietic function in the body, some researchers made a mouse model of osteoporosis and conducted a study. The results showed that with the decrease of bone density in the body, hematopoietic function gradually decreased. And the results showed that osteoporosis can cause the weakening of hematopoietic function in the body. Therefore, it was speculated that the hematopoietic function of patients with osteoporosis was also weak, and the compensatory ability of the body was also relatively poor after the operation. This resulted in the low value of Hb and HCT in the patients after the operation. So we might measure more hidden blood loss during the perioperative period for osteoporosis patients. For this reason, we should assess the bone density of the patient before surgery according to the imaging examination and the patient's medical history. Once the diagnosis of osteoporosis is made, anti-osteoporosis treatment should be initiated. Strengthen the monitoring and management of the hidden blood loss in the perioperative period of osteoporosis patients, and making reasonable intervention to osteoporosis, can together accelerate the postoperative recovery of patients.