Comparison of DAA and PLA Approaches for Total Hip Replacement in the Treatment of Femoral Neck Fractures

Objectives: Femoral neck fractures are becoming more common within no-wadays. This research is to explore the clinical effect of primary total hip replacement (THA) via direct anterior approach (DAA) and posterolateral approach (PLA) in the treatment of femoral neck fracture. Methods: Retrospective analysis of 100 cases of elderly patients with femoral neck fracture who underwent total hip arthroplasty admitted to Tianyou Hospital affiliated to Wuhan University of Science and Technology from January 2019 to January 2022. 50 patients treated with DAA approach were included in the observation group, and 50 patients treated with PLA approach were included in the control group. The operation indexes, postoperative acetabular abduction angle and anteversion angle, hip joint function, Harris score and complications were compared between the two groups. Result: The length of incision in the observation group was shorter than that in the control group, and the amount of intraoperative bleeding and postoperative hospital stay were shorter than those in the control group (P < 0.05); There was a statistically significant difference between the two groups in the ratio of acetabular abduction angle and its safe zone, and the length difference of both lower limbs (P < 0.05), while there was no statistically significant difference between the two groups in the ratio of acetabular anteversion angle and its safe zone, eccentricity, and its recovery rate (P > 0.05); Harris score of hip joint: 6 months after operation, the anterior approach group was


Background
Femoral neck fracture is a common fracture disease in the elderly. With the change of transportation and the aging of the population, the incidence rate of femoral neck fracture increases year by year [1]. The main treatment for femoral neck fracture in the elderly is hip replacement, and the recovery of hip joint function after operation is of great significance [2]. For such patients, hip replacement and other surgical treatments are often used in clinical practice to improve symptoms, promote the recovery of independent activities, and improve the quality of life of patients [3]. The posterolateral approach (PLA) is often used clinically, which is easy to operate, but will damage the external rotator muscles and the posterior joint capsule, which is easy to cause complications such as dislocation of the prosthesis after surgery, and is not conducive to the recovery of joint function [4]. The DAA approach is to perform hip joint replacement from the muscle space between the rectus femoris and the sartorius, tensor fascia lata. Compared with PLA, it has the advantages of minimally invasive, less damage, and faster early functional recovery [5]. In recent years, hidden blood loss has gradually attracted the attention of clinicians and has been regarded as a reference index for functional recovery after joint replacement. Hidden blood loss is found after joint replacement and treated in time to fully restore blood circulation function, which is conducive to postoperative recovery of patients. Therefore, this study will compare the two surgical approaches and analyze their efficacy and complications.

General Information
Retrospective analysis was made on 100 patients with femoral neck fracture who needed THA from January 2019 to January 2022 in the author's hospital. They were randomly divided into control group and observation group with 50 cases each. The control group consisted of 22 males and 28 females, aged from 61 to 78 years, with an average age of (70.01 ± 2.22) years; Affected side: left side 24 cases, right side 26 cases. The observation group consisted of 20 males and 30 females, aged from 63 to 77 years, with an average age of (69.02 ± 3.52) years; Affected side: left side 22 cases, right side 28 cases. There was no significant dif- ference in general data between the two groups (P > 0.05). The study was approved by the hospital ethics committee, the operator has informed the patient of the research purpose before and after the operation, and the patient has known and signed the relevant informed consent form.

Preoperative Preparation
All patients have completed preoperative routine examinations: blood routine examination, biochemical examination, erythrocyte sedimentation rate, C-reactive protein, fasting blood glucose, blood coagulation function, lower limb blood vessel color ultrasound, heart color ultrasound, electrocardiogram, etc. The coagulation function and other indicators were evaluated in detail, and the appropriate prosthesis type and placement position were selected through preoperative template measurement.

DAA Group
The patient lies flat on the operating table, the pubic symphysis is directly oppo- the medullary cavity, place the prosthesis, and reposition the joint, After the activity of hip joint is confirmed to be good and stable, clean the joint cavity, suture layer by layer, and sterilize and bandage.

PLA Group
The patient lies on the healthy side of the operating bed. After anesthesia, the

Postoperative Treatment
The two groups of patients were given the same treatment plan after surgery, and the patients began ankle pump exercise after anaesthesia awake. In the observation group, there was no special position restriction after operation, and the patients could move to the ground early; In the control group, the affected lower limbs should be kept in a neutral and abduction position after operation. When rolling over, a pillow should be clamped between the legs. After lying in bed for about 3 days, the affected lower limbs can be moved to the ground.  SPSS 22.0 software was used for statistical analysis. T-test was used for data analysis and comparison; Chi square test was used to compare the counting data.

Results
All patients were followed up for 12 months.

Comparison of Surgical Conditions and Imaging Indexes of Prosthesis Installation between the Two Groups
Compared with PLA group, DAA group had less hospital stay, less intraoperative bleeding, less postoperative drainage, and longer operation time, with statistically significant differences (P < 0.05), see Table 1 for details. There was no significant difference in the anteversion between the two groups (P > 0.05); The difference in abduction angle and length of both lower limbs between the two groups was statistically significant (P < 0.05), see Table 2

Comparison of Hip Joint Function between Two Groups
See Table 3. The excellent and good rate of Harris score of hip joint: 6 months after operation, the anterior approach group was significantly higher than the posterolateral approach group (P < 0.05). There was no significant difference between the two groups 12 months after operation (P > 0.05). Typical cases are shown in Figure 1, Figure 2. Figure 1 shows a 75-year-old female patient with left femoral neck fracture who was operated through the DAA approach. Figure 1

Discussion
THA is one of the commonly used surgical methods for the treatment of femoral neck fracture, and its clinical efficacy has been widely recognized [8] [9] [10].
However, THA is also one of the reported surgeries with large blood loss (average 1735 ml) [11]. Therefore, reducing THA perioperative blood loss has become a problem that clinical orthopedics doctors pay close attention to and urgently need to solve.
THA has a variety of surgical approaches, among which the posterolateral approach is more commonly used and has the advantages of simple and intuitive operation [12] [13]. However, in recent years, relevant studies [14] [15] believe that THA via posterolateral approach tends to increase the risk of traumatic complications and is not conducive to postoperative rehabilitation of patients.
The DAA approach has gradually become the latest choice for joint surgeons at home and abroad because of its advantages such as less damage to surrounding tissues, quick recovery after operation, etc. [16] [17]. In this study, the amount of intraoperative bleeding, postoperative drainage and hospital stay in the DAA group were less than those in the PLA group, and the differences were statistically significant (P < 0.05). The authors believe that the above results are mainly related to the anatomical advantages of the DAA approach. The DAA approach is superior to the PLA approach in reducing the damage to the patient's tissues, alleviating the patient's pain, and speeding up the patient's recovery.
THA is a very mature operation, whether through DAA or PLA approach, it can often achieve good surgical results. In this study, the Harris score of DAA group was higher than that of PLA group in the early postoperative period, with a statistically significant difference (P < 0.05), but the difference between the two groups was narrowing over time. The results of Wang et al.'s meta-analysis of THA [18] showed that there was no significant difference in Harris scores between DAA and PLA approaches. The reason for analysis is that minimally invasive DAA total hip arthroplasty is less likely to damage the nerves of patients, which can effectively protect the stability of muscle tissue and the rear of the hip joint, and it can make the range of motion of the hip joint unrestricted, which can enable patients to do bending, adduction and other actions earlier, and recover faster after surgery [19]. The posterolateral total hip arthroplasty needs to cut off the muscle group, resulting in soft tissue damage and slow recovery of hip joint function [20]. The author believes that the existence of this difference in this study is still related to the fact that the patients after DAA approach have less pain and better comfort, so they can take early rehabilitation exercise, and the hip joint activity is not restricted.
In this study, 10 patients (8.55%) in the DAA group had a length difference of more than 10 mm, while 17 patients (17.17%) in the PLA group had a statistically significant difference (P < 0.05). Gong Dawei et al. [21] believed that the DAA approach could better control the difference in the length of both legs. The author believes that the existence of this difference is related to the different po- sitions of the two surgical approaches. The DAA group is in supine position, and the PLA group is in lateral position. The supine position can directly touch the bilateral anterior superior iliac spine, and the length of both lower limbs can be compared more intuitively. At the same time, the supine position enables the operator to have a more intuitive view of the placement of the acetabular prosthesis, and the pelvic position is more stable, which can better ensure that the acetabular prosthesis is located in the safety zone [22].
Limitations of this study: 1) This study is a retrospective study, with relatively low evidence level and short follow-up time, which cannot reflect the long-term efficacy of PLA and DAA approaches. 2) This study only focuses on the cases of unilateral total hip replacement, and does not analyze and study the cases of bilateral total hip replacement. The research content is not comprehensive enough.
In conclusion, compared with the PLA approach, the DAA approach is more consistent with the concept of rapid rehabilitation, with advantages such as less trauma, fewer complications, fast recovery, and good short-term effect. However, the implementation of the DAA approach is also limited by its disadvantages such as the need for special eccentric tools and long learning curve. Therefore, under the condition that the hardware conditions are met and the DAA approach is skillfully mastered, the DAA approach is a reliable and effective surgical method, which can more effectively promote the recovery of patients' hip joint function.