Evaluating Postoperative Hidden Blood Loss in Proximal Femoral Nail Anti-Rotation Fixation: The Role of Greater Trochanter Fracture Comminution

Introduction

Intertrochanteric fracture is a severe and common injury that occurs predominantly in the elderly [1]. Fracture fixation with PFNA is a minimally invasive surgery with a small incision (Figure 1) and minimal intraoperative blood loss [2,3]. However, overall blood loss can be substantially greater than that observed intraoperatively [4]. One study showed that overall blood loss was 1473 mL more than that observed intraoperatively in patients undergoing PFNA for intertrochanteric fractures [5]. There are some reports of significant HBL following the operation [5–7]. The HBL refers to unobserved blood loss occurring during surgical procedures and in the postoperative period, which, although not easily detected, can lead to serious complications. Unfortunately, the HBL is often ignored in patients treated with intramedullary fixations because it is a relatively simple surgical procedure, with short duration of surgery and minimal intraoperative blood loss [8]. Larger amounts of HBL can lead to anemia, hypoproteinemia, and severe complications such as cerebral infarction, delirium, shock, and heart failure, endangering the lives of the elderly [9–13].

In our clinical practice, we have observed that that patients with comminuted fractures of the greater trochanter often have significantly increased postoperative HBL (Figures 2, 3). We hypothesized that a comminuted fracture in the greater trochanter is a major cause of massive postoperative HBL when PFNA is used to treat the femoral intertrochanteric fracture. To test this hypothesis, we retrospectively assessed data on postoperative complications, length of hospital stay, and postoperative HBL of patients undergoing PFNA for intertrochanteric fractures in our hospital over the past 5 years. This study compared postoperative HBL in 219 elderly patients with intertrochanteric fractures using PFNA fixation, stratified by greater trochanter comminution status (comminuted vs non-comminuted).

Material and Methods

ETHICS APPROVAL AND STUDY SUBJECTS:

This study was approved by the Medical Ethics Committee of Lianshui People’s Hospital Affiliated to Kangda College (approval no: 2019–014). All methods were performed in accordance with the Declaration of Helsinki. We retrospectively analyzed date on 219 patients who underwent PFNA for intertrochanteric fractures of the femur between March 2019 and June 2024. Inclusion criteria were: (1) 65< age <89 years, (2) injury caused by low-energy trauma, (3) duration of surgery <60 min, and (5) time between surgery and injury <2 days. Exclusion criteria were: (1) patients with coagulation disorder, and (2) patients who received a blood transfusion due to severe anemia.

STUDY DESIGN:

According to whether there was a comminuted fracture in the greater trochanter of the femur, 219 patients were divided into Group A and Group B. The patients with an intact greater trochanter or those with fractures divided into 2 fragments were assigned to Group A (n=68), while the patients with 3 or more fragments were assigned to Group B (n=151). The height and weight of all patients were recorded preoperatively. Since the patients could not be weighted on a conventional scale, their weight was estimated by the orthopedic surgeon supported by the patients’ own information. Upon admission, all patients received anticoagulant treatment with subcutaneous injections of low-molecular-weight heparin calcium every 12 hours. Anticoagulation treatment was suspended 12 h before surgery.

SURGICAL PROCEDURE:

During the surgery, the patients received intraspinal anesthesia, were placed on a traction operating table, and underwent closed reduction of the fracture under fluoroscopic guidance using a C-arm X-ray machine. The incision was made above the apex of the greater trochanter, approximately 3 cm in length. With the apex of the greater trochanter as the entry point, a guide needle was inserted into the femoral bone marrow cavity. The intramedullary nail was inserted into the medullary cavity along the guidance needle after creating a proximal femoral channel using an electric drill. Under fluoroscopic guidance, a Kirschner wire was drilled below the central axis of the femoral neck. Then, a spiral blade with appropriate length was hammered into the femoral neck along the Kirschner wire. A screw was inserted into the tail of the intramedullary nail to firmly attach the spiral blade to the intramedullary nail. After a screw was drilled into the bilateral cortical bone of the proximal femur through the distal hole of the intramedullary nail, the fracture was fixed with PFNA. No drainage tube was placed in the incision.

HBL MEASURES:

HBL was calculated as follows [10,14]:

Overt blood loss was defined as the intraoperative blood loss (calculated as the liquid in the suction bottle minus the irrigation fluid used during the operation, plus the net weight increase from weighing gauze dressings, etc.) combined with postoperative visible blood loss (wound drainage).

The estimated total blood volume (TBV) was calculated as follows:

Hct_0h was the hematocrit (Hct) level at the beginning of the operation, and Hct_48h was the patient’s Hct 48 hours after the operation.

OTHER OUTCOME MEASURES:

Various complications were prevented and treated, and anticoagulant treatment resumed 12 hours after surgery. The surgery duration was recorded. Postoperative patients were closely monitored for complications such as shock, acute cerebral infarction, and heart failure. A head CT scan was performed again 24 hours after surgery to compare with preoperative results for acute cerebral infarction.

STATISTICAL ANALYSIS:

Statistical analysis was performed using SPSS version 24.0 software (SPSS, Inc., Chicago, IL, USA). Descriptive data are expressed as mean±standard deviation (SD), median (min-max), or number. The chi-square test was used to compare categorical variables between the groups, while Welch’s t test was used to compare numerical variables between the groups. P values <0.05 were considered statistically significant.

Results

Patients who received blood transfusions after surgery were excluded from the study due to significant impacts on their hemoglobin level results. In Group A, 3 patients were excluded, and in Group B, 12 patients were excluded.

Group A comprised 16 males and 52 females (mean age 76.45±9.77 years; range 63–89), while Group B included 43 males and 108 females (mean age 78.27±11.02 years; range 66–87). No significant intergroup differences were observed in sex distribution (P=0.512) and age (P=0.168).

Hypertension (55.88% vs 50.99%), diabetes mellitus (30.88% vs 32.45%), and old cerebral infarction (26.47% vs 24.50%) were the predominant comorbidities, with no significant intergroup differences observed in hypertension (P=0.082), diabetes mellitus (P=0.148), or prior cerebral infarction (P=0.381).

The mean operative duration was similar between the 2 groups – 39.91±8.09 minutes (range 23–55) in Group A and 40.24±7.89 minutes (range 20–54) in Group B (P=0.077). Demographic and clinical characteristics of patients are shown in Table 1.

The mean intraoperative blood loss was significantly lower in Group A (70.01±24.14 ml; range 50–115 ml) compared to Group B (98.55±29.78 ml; range 70–210 ml) (P=0.000). Group A had a mean HBL of 758.0±195.5 mL (range: 580.1–1208.4), while Group B had a significantly higher value of 1151.5±282.2 mL (range: 1040.1–1413.0) (P=0.000). These findings collectively suggest that comminuted fractures of the greater trochanter are associated with an increased risk of hemorrhage during and after surgery. Furthermore, statistically significant differences were demonstrated in postoperative complications – acute cerebral infarction (P=0.015), hemorrhagic shock (P=0.041), and heart failure (P=0.036) – and hospital length of stay (P<0.000) (Table 2).

Discussion

The clinical research results showed that the patients with comminuted fractures of the greater trochanter had significantly greater postoperative HBL than those with non-comminuted fractures. Patients with comminuted fractures had significantly higher risks of postoperative acute cerebral infarction, hemorrhagic shock, and heart failure, and a significantly longer average hospital stay, compared to patients with non-comminuted fractures.

Our findings agree with those of Yu et al, who found that PFNA and dynamic hip screw (DHS) techniques result in considerable postoperative HBL when treating geriatric intertrochanteric fractures, with PFNA showing significantly greater HBL compared to DHS [8]. Studies by other scholars have also confirmed that substantial hidden blood loss is frequently associated with PFNA internal fixation following intertrochanteric femoral fractures [4–7]. The primary contributors to high HBL after PFNA fixation of femoral intertrochanteric fractures in elderly patients include: (1) inadequate interstitial fluid return, (2) hemolysis, (3) damage to red blood cells, and (4) ongoing blood loss before and after surgery [15]. Other factors also played significant roles, including the use of anticoagulants, osteoporosis, fracture reduction, and intramedullary penetration, including use of anticoagulant, osteoporosis, fracture reduction, and intramedullary penetration [5,16–19]. However, their analysis did not account for the potential impact of greater trochanter comminution status (whether the fracture was comminuted or not) on the volume of HBL. The present retrospective analysis of 219 cases over the past 5 years found a significant association between comminuted fractures of the greater trochanter and large volumes of postoperative HBL.

Several studies have revealed a close relationship between HBL following intramedullary nailing fixation and the classification of intertrochanteric fractures. The main classification systems for such fractures include the AO and Evans classifications. The results indicate that unstable or advanced types of intertrochanteric fractures are associated with increased HBL [20]. However, our study did not use the aforementioned traditional classification systems but instead focused on the severity of greater trochanteric fractures. Patients with an intact greater trochanter or those with fractures divided into 2 fragments were included in Group A, while patients with 3 or more fragments were included in Group B. According to the Evans classification, Group A included Type I, Type IIB, and reverse intertrochanteric fractures, while Group B included Type IIA and Type III. According to the AO classification, Group A included Types A1, A21, A22, and A3, while Group B included Type A23.

Postoperative acute cerebral infarction is closely related to hypoperfusion of cerebral tissue, often secondary to acute excessive blood loss [21–23]. Hemorrhagic shock and heart failure result directly from acute excessive blood loss [24,25]. Excessive blood loss and acute anemia increase the risk of cardio-cerebrovascular events, which are associated with high mortality rates [26]. The increased average length of hospital stay results from various complications [27]. All of these complications can be caused by massive postoperative HBL. The above results confirmed our hypothesis.

To understand this study’s hypothesis, the local anatomical structure of the femoral trochanter and its pathological manifestations after injury and surgery must be carefully analyzed. The greater trochanter is mainly composed of cancellous bone, which contains a many of tiny blood vessels [28]. Intertrochanteric fractures are a type of metaphyseal fracture with rich blood supply [19]. When a femoral intertrochanteric fracture occurs, the small blood vessels in the cancellous bone are also destroyed [29]. Additionally, the integrity of the cortical bone and surrounding periosteum is damaged, reducing the ability to restrict expansion of the hematoma [30]. During the surgery, the processes of fracture reduction and intramedullary penetration destroy the small blood vessels temporarily blocked by clots, resulting to persistent bleeding [31–33]. The displacement of bone fragments in comminuted fractures is much greater than in non-comminuted fractures [34]. Subsequently, the degree of small-vessel damage inevitably increases with the degree of comminution of the fracture [35]. The blood is more likely to seep into the tissue compartments through the severely injured cortical bone and periosteum, and the pressure inside the hematoma is reduced, making it difficult to stop bleeding. Therefore, the amount of HBL after surgery will naturally increase. A large amount of blood diffuses under the deep fascia and/or within the superficial fascia, leading to the formation of large areas of cyan-purple ecchymosis [36]. The aforementioned are the pathologic basis of massive HBL after PFNA internal fixation for comminuted fracture of the greater trochanter of the femur.

Our study has some limitations to consider. First, the sample size was not large, potentially leading to small deviations in the study results. Second, the degree of osteoporosis in patients was inconsistent, slightly affecting the study results. Third, differences in coagulation function among patients would affect the amount of blood lost after surgery. Fourth, due to concerns about the large impact on the hemoglobin results, the patients receiving blood transfusions due to massive HBL were excluded from the study—3 patients in Group A and 12 patients in Group B were excluded, and their data were not analyzed and compared, resulting in a smaller difference in postoperative HBL between the groups, but this did not affect our conclusion, and in fact supported it. Fifth, the conclusion of this study lacked significant innovation and did not present technical methods for mitigating bleeding. We will conduct further research in the future, enlarge the sample size, and stratify patients based on degree of osteoporosis and coagulation function to narrow the differences between groups and obtain more precise results. Particularly, we will focus on minimizing HBL and addressing complications arising from it. Sixth, due to the inability to accurately measure patients’ height and weight, these values could only be estimated based on the orthopedic surgeon’s clinical experience. This approximation might have introduced variability in the calculated TBV, thereby ultimately affecting the accuracy of HBL determination. Finally, no standard method has been established for measuring intraoperative and postoperative blood loss. Consequently, our evaluation relied on comparison with an established technique rather than against the actual quantity. The assessment of so-called ‘true’ blood loss was limited by methodological constraints.

Conclusions

When PFNA is used for internal fixation of intertrochanteric fractures of the femur, although there are many factors that can lead to massive postoperative HBL, comminuted fractures of the greater trochanter are also a significant factor that cannot be ignored, and the orthopedic team members need to be aware of the risk. Corresponding measures should be taken to decrease blood loss, thereby ensuring perioperative safety of patients.