Total Hip Replacement vs. Internal Fixation in the Treatment of Femoral Neck Fractures in the Elderly

Background: To evaluate the effects of total hip replacement and internal fixation on the outcome of femoral neck fractures in the elderly. Methods: A retrospective study was conducted in a total of 79 individuals diagnosed with Garden I or Garden II femoral neck fractures aged from 56-71 years old from October 2012 to May 2019. Patients treated with total hip replacement were grouped into group 1, while those treated with internal fixation were grouped into group 2. Baseline characteristics were compared between the two groups to eliminate extra factors. Postoperative activity time, blood loss, length of hospital stay, and length of surgical incision were compared between the two groups. Besides, postoperative complications and hip function (Harris score) were detected to evaluate the final effects in the two groups. Results: Baseline characteristics were similar between the groups, but the mean duration of surgery was more in group 1 than that in group 2 ( p <0.0001). Blood loss and length of surgical incision were both larger in group 1. However, the incidence of such postoperative complications as lung infection, urinary tract infection and thrombosis of lower limb was lower in group 1 compared with those in group 2. Moreover, the hip function (Harris score) was also better after total hip replacement compared with that after internal fixation. Conclusions: Total hip replacement provides satisfactory clinical outcomes, but with longer operation time and increased blood loss compared with internal fixation.

postoperative complications as lung infection, urinary tract infection and thrombosis of lower limb was lower in group 1 compared with those in group 2. Moreover, the hip function (Harris score) was also better after total hip replacement compared with that after internal fixation.
Conclusions: Total hip replacement provides satisfactory clinical outcomes, but with longer operation time and increased blood loss compared with internal fixation.

Background
The femoral neck fracture is of high frequency in the elderly clinically [1][2][3]. With the global aging of population, the proportion of the elderly has been increasing, and the incidence of femoral neck fractures is also rising as expected [4][5][6]. It is estimated that 3 the number of patients with hip fractures will be up to approximately 6 million in the world by 2050 [7]. With the improvement of medical technology, the development of built-in materials and the progress in surgical techniques, the surgical treatment for femoral neck fractures has been widely recognized. The common surgical treatment includes the open or closed hollow screw internal fixation, muscle bone flap, and artificial hemi/total hip replacement. It has been found in studies that reduction internal fixation can be performed for patients aged below 60 years old, while hip replacement can be conducted for patients aged above 80 years old [8]. However, the initial surgical methods for patients with femoral neck fractures aged 60-80 years old are still controversial [8,9].
Due to the influences of life expectancy, preoperative living ability, mental state, postoperative functional recovery and quality of life, the risk of avascular necrosis and nonunion of the femoral head is higher in patients undergoing internal fixation, with a higher possibility of reoperation, so it is difficult to be accepted by patients [10,11].
However, there are also such problems as short durable years and prosthesis dislocation in total hip replacement [12]. Previous studies indicated that the optimal treatment factors for femoral neck fractures include fracture displacement, patient's age, risk status, functional requirements, cognitive function and physical ability [13][14][15][16]. In addition, with the extension of human life expectancy and the diversity and complexity of diseases, the expected life span of patients increases or decreases, making it difficult for clinicians to perform joint replacement [17]. Surgical treatment should be adopted for Garden I and II impacted fractures without displacement, unless there are surgical contraindications. This prospective randomized study was conducted to reveal different outcomes of total hip replacement and internal fixation in patients with Garden I or Garden II femoral neck fractures.

Methods 4
After Ethics Committee of Affiliated Dongtai Hospital of Nantong University approved the study, this retrospective study was performed in Affiliated Dongtai Hospital of Nantong University from January 2015 to September 2018. Inclusion criteria: patients aged 60-80 years old, with the time from injury to admission <one week, and Garden I or II femoral neck fracture, and those receiving total hip arthroplasty or internal fixation with closed reduction and hollow compression screw. Exclusion criteria: patients aged <60 or >80 years old, those with open comminuted fractures or multiple fractures at any site at low extremities, or a previous history of surgery on lower limbs. According to surgical methods, the patients were divided into total hip replacement group (group 1, n = 40) and internal fixation group (group 1, n = 39). In group 1 (mean age = 63.75±4.07, male/female ratio = 11:29), patients received total hip replacement by using hip prosthesis, acetabulum screw, Ceramic ball head (Dragonbio, Wuhan, China) and BENCOX Delta Head. In group 2 (mean age = 63.36±3.93, female / male ratio = 27:12), 3.3 mm locking compression plate (MEDIOX, Eger, Hungary) was employed to fix fractures. The mechanism of injury and fracture type were similar in both groups ( Table I). The same team conducted all the sugery.

Surgical technique
In group 1, the operation was performed under a lateral position through the modified Hardinge approach [18] after general anesthesia or continuous epidural anesthesia. The skin was cut open layer by layer along the greater trochanter of femur to expose the hip joint, the femoral head was excised, the circumferential cartilage and round ligament were removed, and the acetabulum cartilage was honed from small to large using the file at the abduction of 40-45° and anteversion of 15-25°. Then according to the size of file, the appropriate acetabular cup with lining was placed, followed by femoral medullary overreaming at the anteversion of 10-15°. According to the size of medullary file, the appropriate femoral prosthesis was placed for reduction, as well as flexion and extension, adduction, internal and external rotation of hip joint. After there was no dislocation trend, the femoral head prosthesis was officially installed for the reduction of hip joint, and the stability of hip joint was checked again. After there was no dislocation trend, the wound was washed, the negative pressure drainage tube was placed, and the skin was sutured layer by layer, followed by pressure dressing (Figure 1).
In group 2, the C arm-assisted closed replacement was performed under a horizontal position after general anesthesia or continuous epidural anesthesia. After anatomical reduction, routine disinfection and draping, a guide pin was percutaneously drilled in parallel to the femoral neck at 3-4 cm below the greater tuberosity of femur, which was also parallel to the axis of the femoral neck and the anteversion angle. After the position was confirmed, three guide pins were drilled in a parallel and triangular manner. After the angle and position were confirmed again, a small incision (about 1 cm long) was percutaneously made along the guide pin, and the drill hole was expanded using the hollow drill under the protection of the sleeve. After depth detection, the appropriate hollow screw was screwed into the bone, with the screw tip at about 0.5-1 cm below the articular surface without penetrating the articular surface. The other two screws were also screwed along the other two guide pins in the same way, and the guide pins were pulled out after the satisfactory position, angle and depth were confirmed, followed by routine suture of wound ( Figure 2).

Statistical analysis
All data were analyzed by statistical software Statistical Product and Service Solutions (SPSS) 19.0 (SPSS Inc., Chicago, IL, USA), and quantitative data were shown as mean ± standard. Unpaired t-test was used for quantitative data in single-factor test. Rank sum test was used for data not meeting normal distribution. Quantitative data were shown as 6 rate or percentage, and χ 2 test was performed. p<0.05 demonstrated that the difference was statistically significant.

Results
The baseline characteristics were similar in the two groups. The time from onset to surgery was (4.68±1.56) days in group 1 and (4.90±1.55) days in group 2. In addition, Comparison of hypertension, diabetes, rheumatoid arthritis and coronary heart disease between the two groups suggested no statistically significant differences (p>0.05) ( Table   I).
As shown in Table II Postoperative complications were also used to compare two groups (Table III) (Table IV).
Moreover, the Harris score was markedly increased in both group 1 and group 2 from 3 months to 6 months or 6 months to 12 months after surgery ( Figure 3).

Conclusions
Total hip replacement has longer operation time and larger trauma, which requires better physical conditions of patients compared with internal fixation. However, it can enable the 9 patients to go to ground activity earlier, conduct limb partial weight bearing and functional exercise in shorter time, and realize better postoperative hip function recovery.
The internal fixation has relatively short operation time and small trauma, but the patients are not able to conduct weight bearing and corresponding functional exercise for a long time. In clinic, the patients' age, fracture type and body shape should be considered comprehensively to choose the most appropriate surgery.

Declarations
Ethics approval and consent to participate The study was approved by the Ethics Committee of Affiliated Dongtai Hospital of Nantong University.

Consent for publication
Not applicable.

Availability of data and materials
The datasets in the study are available from the corresponding author on reasonable request.

Competing interests
The authors declared that they have no conflict of interest.        Harris score was markedly increased in two groups at the point of 3 months, 6 months and 12 months after surgery. The score in group 1 was more than that of group 2 at three different times.