The efficacy of anatomical biomimetic reconstruction of the external rotator muscle group combined with repair of the annular ligament in hip replacement surgery

doi:10.21203/rs.3.rs-8260372/v1

Background With the significant increase in the incidence of femoral neck fractures in the elderly, optimizing the selection of surgical techniques has important clinical value for improving outcomes and reducing perioperative risks. Currently, the focus of related research has shifted from mechanical structural repair to biomechanically precise reconstruction based on the principles of biomimetic medicine. Although the theory of anatomical reduction and repair is widely accepted, further research is still warranted to achieve an optimal balance between repair stability and joint mobility through personalized treatment strategies.

Methods A retrospective cohort study was conducted involving 124 elderly patients with unilateral femoral neck fractures who were admitted to the Hospital between June 2021 and March 2023. All patients were operated on via a posterolateral approach. Based on comprehensive analysis of clinical data and preoperative physician–patient communication, 65 patients were assigned to the experimental group and underwent anatomical biomimetic reconstruction of the external rotators combined with repair of the zona orbicularis; the remaining 59 patients were assigned to the control group and received conventional suture repair (fixation of the joint capsule combined with the external rotator tendons to the greater trochanter). The following parameters were recorded for both groups: operative time, intraoperative blood loss, incision length, wound healing status, length of hospital stay, complication rate, and readmission rate. Postoperative outcomes including VAS score, Harris Hip Score, hip flexion–extension range of motion, and internal–external rotation range of motion were compared to evaluate the clinical utility of anatomical biomimetic reconstruction of the external rotators combined with zona orbicularis repair in unilateral hemiarthroplasty.

Results The two groups demonstrated comparable baseline characteristics (p>0.05). Perioperatively, the experimental group showed significantly reduced intraoperative blood loss and shorter incision length (p<0.05), while operative time was longer but not statistically significant. Wound healing (1 vs. 2 cases of Grade B healing) and hospital stay were similar between groups. Functional outcomes significantly favored the experimental group, with improved VAS scores, Harris hip scores, and hip range of motion (flexion-extension and internal-external rotation). Radiographically, the experimental group achieved greater anteversion (p<0.05) with comparable acetabular abduction angle. No cases of prosthetic loosening, periprosthetic infection, or fracture occurred during follow-up. Dislocation rates after discharge (1 vs. 3 cases, p>0.05) did not differ significantly, though a numerical trend favoring the experimental group was observed.

Conclusions Anatomical biomimetic reconstruction not only provides reliable joint stability but also enables superior functional outcomes, with a higher proportion of patients returning to their preinjury activity levels compared to conventional techniques. This offers a valuable perspective in the clinical decision-making process for surgical management.

Anatomical biomimetic reconstruction

external rotator muscle group

artificial hip replacement

Total hip arthroplasty (THA) serves as the definitive intervention for displaced femoral neck fractures in elderly patients and end-stage hip joint pathologies [1]. The posterolateral approach (PLA) has become the prevailing global standard due to its excellent acetabular exposure, preservation of the abductor mechanism, and technical convenience. However, this approach inherently requires division of the short external rotator muscles and the posterior joint capsule [2-5]. Disruption of these posterior stabilizers is strongly associated with postoperative dislocation—the second most common indication for THA revision, with reported incidence rates ranging from 1.1% to 10.7% [6-8]. Current evidence confirms that meticulous repair of these structures can effectively restore the posterior soft-tissue barrier and reduce dislocation risk. Although current mainstream repair techniques for the external rotators—such as bone-tendon repair, anchor suture fixation, and soft tissue-to-tissue repair—have demonstrated some efficacy in reducing dislocation rates, they inevitably present challenges including excessive tensile forces leading to avulsion fractures, secondary ruptures, and substantial cost burdens. The absence of a standardized reconstruction protocol and the frequent failure to achieve reliable mechanical restoration of the divided tissues remain major factors contributing to persistent joint instability [9-11]. This study focuses on the management strategy of the short external rotators and joint capsule—key stabilizers—in hemiarthroplasty. Its core contribution lies in proposing and validating an innovative technique designed to achieve "anatomically authentic reconstruction." This approach enables maximal restoration of the external rotators to their anatomical position, reduces dead space around the piriformis fossa, minimizes hematoma and fluid accumulation, and reconstitutes the joint capsule as a continuous tubular structure. Rather than being confined to simple tissue repair, this study moves beyond conventional practice by emphasizing precise reconstruction to restore the native anatomical architecture and biomechanical environment of the posterior hip complex.

Design

Retrospective cohort study

Time and location

The trial was conducted from June 2021 to March 2023 at the Department of Joint Surgery.

Inclusion criteria

① Diagnosed with femoral neck fracture based on preoperative anteroposterior and lateral X-ray images of the hip joint and CT three-dimensional reconstruction; ② Age ≥75 years old with complete clinical records; ③ Fresh fracture (time from injury to admission ≤7 days); ④ Garden classification type III or IV; ⑤ Preoperative assessment of bilateral lower limb motor function, sensory nerve conduction, and muscle strength showed no abnormalities; ⑥ All patients underwent posterior lateral approach hemiarthroplasty and were able to tolerate the surgical treatment method used in this study, and signed the relevant informed consent form.

Exclusion criteria

① Patients with underlying conditions such as severe heart, liver, or kidney dysfunction, or systemic malignant tumors that may lead to pathological fractures;② Patients with cognitive impairments who cannot cooperate with postoperative efficacy assessments (e.g., Alzheimer's disease, etc.); ③ Postoperative follow-up duration less than 12 months or missing critical data; ④ Concurrent fractures of the same-side lower limb or pelvis, active hip joint infection, prior hip joint surgery history, or developmental deformities; ⑤ Outerbridge grading of acetabular cartilage degeneration ≥ Grade III or radiologically confirmed Charcot joint disease; ⑥ Long-term use (continuous use ≥ 3 months) of corticosteroids or anticoagulant drugs within 1 year prior to surgery; ⑦ Bone density testing indicating severe osteoporosis (T-score ≤ -3.0 SD).

Participants and groups

A retrospective analysis was conducted on 124 elderly patients with unilateral femoral neck fractures who were admitted to the Department of Joint Surgery at the Hospital between June 2021 and March 2023. All enrolled patients underwent hemiarthroplasty via the posterolateral approach. Based on comprehensive clinical data and preoperative physician–patient communication, patients were allocated according to their preference into either the experimental group (n=65), which received anatomical biomimetic reconstruction of the external rotators combined with repair of the zona orbicularis, or the control group (n=59), which underwent conventional suture repair (fixation of the joint capsule and external rotator tendons to the greater trochanter). This study was approved by the institutional ethics committee of our hospital , and written informed consent was obtained from all participants.

Surgical method

Preoperative preparation

All patients underwent comprehensive imaging assessments upon admission to evaluate the acute/chronic nature and stability of fractures; Bone density assessment was used to evaluate bone quality; routine blood biochemical tests and 25-hydroxyvitamin D3 tests were performed, and tumor marker tests were conducted on all patients to assess their overall health status. Preoperative correction of anemia (iron supplements + EPO for patients with Hb < 90 g/L) and tranexamic acid administered in divided doses (1 g intravenous infusion 15 minutes before incision); the surgical site was covered with domestically produced 3M iodine film to prevent infection, and the prosthesis was provided by Tianjin Zhengtian Company .All surgical procedures were performed by the same senior attending surgeon in our department. Our institution has obtained the requisite certification to perform this specific technique.

Experimental group surgery method

Based on the patient's cardiopulmonary function and overall condition, spinal-epidural combined anesthesia is prioritized. General anesthesia is administered for patients with contraindications. Taking the right hip joint as an example, the patient is positioned in a lateral decubitus position. After routine disinfection and draping, a modified Gibson incision is made: Starting 5 cm distal to the iliac crest, the incision is made in an arc outward along the posterior border of the greater trochanter to the proximal femur. The subcutaneous tissue is incised layer by layer, and the gluteus maximus muscle fibers are bluntly dissected along their course to expose and protect the sciatic nerve. At the intertrochanteric crest, the attachment points of the external rotator muscle group, including the quadratus femoris muscle and the obturator internus and externus muscles, are transected. Expose the joint capsule. Incise the posterior joint capsule downward along the junction of the middle and outer thirds of the femoral neck at its attachment point on the femoral side. Do not perform any procedures on the acetabular side to preserve the labrum as much as possible. From this incision site, incise the joint capsule vertically along the acetabular margin, taking care to protect the labrum. Do not perform any special procedures on the posterior inferior portion of the joint capsule to maintain its integrity. The severed external rotator muscle group and joint capsule complex are folded back toward the muscle belly and temporarily fixed to the gluteus maximus fascia, forming a dynamic neural protective barrier to effectively prevent intraoperative traction injury to the sciatic nerve and its branches. The anteversion angle (15° ± 5°) is determined using a medullary cavity locator, and a graded medullary reaming technique is used to match the femoral prosthesis. After installing the trial model, assess lower limb length and joint stability. Once confirmed, implant the bone cement-type femoral stem. During acetabular side processing, ensure the tension of the external rotator muscle group-joint capsule complex is maintained to avoid excessive traction causing injury to the superior gluteal neurovascular bundle. Perform a stepwise four-point suture using absorbable sutures: the first suture is inserted vertically from the lateral margin of the piriformis fossa into the gluteus medius tendon, passing through and exiting from the medial side; the second suture is inserted from the opposite side of the wound margin, penetrating the tendinous tissue of the external rotator muscle group and the deep layer of the joint capsule from the outside to the inside; The third suture is inserted 1 cm from the previous suture in the opposite direction, penetrating from the inner layer of the joint capsule outward through the external rotator tendon membrane; the final suture is placed 1 cm from the third suture in the piriformis fossa region, vertically penetrating the gluteus medius tendon from the inside outward. After tying the suture, the external rotator tendon membrane complex is precisely anatomically repositioned slightly below the gluteus medius muscle and terminates near the piriformis fossa. Joint capsule reconstruction involves using high-strength tendon sutures to perform “edge-to-edge” anastomosis of the iliofemoral ligament and the annular ligament, restoring the integrity of the cylindrical structure of the joint capsule. After irrigation of the surgical field, the deep fascia, subcutaneous tissue, and epidermis are layered and sutured, with sterile dressings covering the wound.（Figure 1）

Control group surgery method

The control group underwent conventional posterior lateral approach total hip arthroplasty using conventional suturing techniques. The joint capsule and external rotator muscle tendons were woven together using high-strength tendon sutures, tested for tensile strength to rule out the possibility of avulsion, and then fixed to the greater trochanter. The remaining steps were the same as those in the experimental group.

Postoperative management

Postoperative continuous monitoring of hemodynamic parameters, routine thromboprophylaxis, sequential treatment with broad-spectrum antibiotics, NSAIDs combined with nerve block analgesia, proton pump inhibitors, and volume support protocols. For patients with lower limb swelling, vascular ultrasound angiography should be performed immediately to assess and rule out the possibility of embolism. If venous system abnormalities are confirmed, a multidisciplinary collaborative diagnosis and treatment mechanism should be initiated. Hemodynamic parameters should be dynamically monitored within 72 hours postoperatively. A tiered blood transfusion protocol should be implemented based on hemoglobin fluctuations (Hb < 100 g/L to assess transfusion indications, with transfusions administered as appropriate; Hb < 70 g/L for emergency transfusions). The affected limb should be immobilized in a neutral rotational position, and hip flexion-adduction-internal rotation composite movement patterns should be strictly restricted for 21 days postoperatively. Intermittent pneumatic compression therapy should be initiated 24 hours postoperatively to optimize venous return. The rehabilitation program is implemented in four progressive phases: isometric muscle strength training is initiated in the early perioperative period; after 48–72 hours postoperatively, protective weight-bearing with a walker is initiated following dynamic balance assessment; after 14 days, transition to crutch-assisted gait retraining; and by 4–6 weeks, achieve unassisted walking, concurrently establishing a protective joint range of motion training regimen.

Main Observation Indicators

（1）Perioperative-related indicators:Record the surgical duration, intraoperative blood loss, incision length, incision healing status, and hospital stay for both groups of patients.

（2）Efficacy evaluation indicators:Record the VAS scores, Harris scores, hip flexion-extension range of motion, internal rotation-external rotation range of motion, and time to full weight-bearing for both groups of patients at 1 month, 3 months, and 6 months postoperatively to evaluate clinical efficacy.Outcome data were prospectively collected by trained nursing staff through face-to-face interviews in the ward using standardized visual analog scale (VAS) and Harris Hip Score (HHS) instruments. Postoperative follow-up assessments were primarily conducted during outpatient visits. For patients unable to attend in-person appointments, structured telephone interviews or secure electronic questionnaire links were utilized to obtain VAS and HHS data. All assessors underwent standardized training to ensure inter-rater reliability. Loss to follow-up was documented to minimize attrition bias.

（3）Imaging-related indicators:Patients were followed up at regular outpatient visits at 1 month, 3 months, and 1 year postoperatively, with repeat X-rays of the affected hip joint in anteroposterior and lateral views, as well as pelvic X-rays. CT scans were performed as needed. Imaging studies were used to accurately measure the acetabular anteversion angle, abduction angle, and lower limb length, and to assess for prosthesis loosening or periprosthetic fractures.All radiographic assessments were independently performed by three attending physicians with the rank of associate chief or higher, all of whom were blinded to patient clinical information. To ensure reliability, the radiographic images were exchanged among the evaluators for a second round of independent review after the initial assessment. Any discrepancies in evaluation were resolved by a separate senior expert with advanced qualifications, thereby minimizing potential observer bias.

（4）Complication-related indicators：Closely monitor for dislocation or prosthesis-related infections during hospitalization and subsequent follow-up, and maintain detailed records.

Statistical analysis

Statistical analysis was performed using SPSS 27.0 software. The K-S test was used to assess the normality of continuous variables in the indicators. For data meeting the criteria for normal distribution, a two-sample t-test was conducted, with results expressed as mean ± standard deviation. Count data were presented as percentages, and intergroup comparisons were performed using the chi-square test; repeated measures data were analyzed using analysis of variance (ANOVA). All statistical analyses were performed using SPSS 27.0, with P < 0.05 considered statistically significant.The statistical methods and all results of this study were reviewed by a statistical expert at the Hospital .

Participant Analysis

A total of 130 patients with unilateral elderly femoral neck fractures were included and divided into two groups based on the method of posterior soft tissue repair of the hip joint: the experimental group (using anatomical biomimetic reconstruction of the external rotator muscle group combined with the iliotibial band repair, n=65) and the control group (using conventional suturing methods, n=59). Two and four patients in the experimental and control groups, respectively, were excluded due to incomplete follow-up data, resulting in 124 patients included in the final analysis.The flow chart of the two groupings is shown inFigure 2。

Comparison of the general data of the two groups

The experimental group included 26 males and 39 females, aged between 76 and 89 years, with an average age of (83.2 ± 5.3) years; the affected sites included 28 cases on the left side and 37 cases on the right side. Garden classification: 29 cases of type III and 36 cases of type IV. The control group included 25 males and 34 females, aged between 675 and 85 years, with an average age of (82.12 ± 2.65) years. The affected sites included 24 cases on the left side and 35 cases on the right side. According to the Garden classification, there were 25 cases of Type III and 34 cases of Type IV. There were no significant differences between the two groups in terms of general characteristics (p > 0.05).The specific analysis results are shown in Table 1.

Table 1 Comparison of general information between the two groups of patients

Indicator	Experimental Group(n=65)	Control Group(n=59)	Statistic Value	P
Gender(Male/Female, case)	26/39	25/34	χ²=0.06	P>0.05
Age	83.2±5.3	82.12±2.65	t=1.46	P>0.05
BMI	22.8±1.8	23.32±1.20	t=1.95	P>0.05
Side	28/37	24/35	χ²=0.04	P>0.05
Garden Classification (III/IV）	29/36	25/34	χ²=0.06	P>0.05
Surgical Waiting Time	3.0±0.82	3.0±0.8	t=0.46	P>0.05

Comparison of perioperative-related indicators

The experimental and control groups exhibited one and two cases of Grade II wound healing, respectively. All such incisions eventually healed well following a standardized protocol of active anti-infective therapy, regular dressing changes, and close monitoring. Comparative analysis revealed that the experimental group was associated with significantly less intraoperative blood loss and a shorter incision length than the control group (p < 0.05 for both). Although the operative time was longer in the experimental group, the difference did not reach statistical significance (p > 0.05). No significant intergroup differences were observed in final wound healing grade or the duration of hospital stay (p > 0.05).The specific analysis results are shown in Table 2.

Table 2 Comparison of perioperative data between the two groups of patients

Indicator	Experimental Group(n=65)	Control Group(n=59)	Statistic Value	P
Operation time	87.6±5.96	85.6±4.87	t=2.06	P>0.05
Intraoperative blood loss	223.6±15.13	237.5±14.66	t=-5.21	P<0.05
Incision length	8.42±0.3	9.06±0.4	t=-10.0	P<0.05
Incision healing status (case, Grade A, Grade B, Grade C)	64/1/0	57/2/0	χ2=1.54	P>0.05
Hospitalization time	11±1.5	11.5±1.8	t=-1.67	P>0.05

Comparison of efficacy evaluation indicators

The time to full weight-bearing activity did not differ significantly between the two groups (p > 0.05). However, compared with the control group, the experimental group demonstrated significantly better postoperative outcomes in terms of VAS scores, Harris hip scores, and hip range of motion (including both flexion–extension and internal–external rotation). These findings suggest that the experimental technique may yield superior long-term functional prognosis relative to the conventional approach.The specific analysis results are shown in Table 3、Table 4 andFigure 3.

Table 3 Comparison of VAS scores and Harris scores between the two groups of patients

Group	VAS			Harris
Group	1 month after surgery	3 months after surgery	6 months after surgery	1 month after surgery	3 months after surgery	6 months after surgery
Experimental Group	5.65±0.76	3.19±0.76	1.56±0.39	69.52±2.87	88.10±1.24	92.48±1.20
Control Group	5.78±0.86	5.03±0.69	2.00±0.71	67.54±2.90	87.02±1.19	90.01±1.50
t	0.58	8.23	3.21	2.01	3.57	6.89
p	P>0.05	P<0.05	P<0.05	P<0.05	P<0.05	P<0.05

Table 4 Extension-flexion ROM and internal-external rotation ROM in the two groups of patients

Group	Extension-flexion ROM			internal-external rotation ROM			Time to Full Weight-Bearing Activity
Group	1 month after surgery	3 months after surgery	6 months after surgery	1 month after surgery	3 months after surgery	6 months after surgery	Time to Full Weight-Bearing Activity
Experimental Group	78.63±2.99	101.68±3.54	130.54±2.16	47.62±2.60	60.19±3.61	69.36±2.97	37.96±4.82
Control Group	76.28±3.37	99.49±3.66	126.32±2.10	45.85±2.88	58.76±3.75	66.52±2.56	39.15±5.21
t	2.58	2.21	4.57	2.11	1.58	2.93	-1.21
p	P<0.05	P<0.05	P<0.05	P<0.05	P<0.05	P<0.05	P>0.05

Comparison of imaging-related indicators and incidence of complications

No significant intergroup difference was observed in the postoperative acetabular abduction angle (p > 0.05). In contrast, the experimental group exhibited a significantly greater anterior tilt angle compared with the control group (p < 0.05). During regular follow-up, no cases of prosthetic loosening, prosthesis-related infection, or periprosthetic fracture occurred in either group. No dislocations were recorded during hospitalization; however, after discharge, one dislocation occurred in the experimental group and three in the control group. All dislocations were successfully managed with closed reduction under anesthesia. The difference in dislocation rates between the groups was not statistically significant (p > 0.05).The specific analysis results are shown in Table 5.

Table 5 Comparison of postoperative imaging parameters and complication rates between the two groups of patients

Indicator	Experimental Group(n=65)	Control Group(n=59)	Statistic Value	P
AV	18.45±0.94	14.46±0.92	t=6.32	<0.001
ABD	42.65±2.18	43.58±2.02	t=-2.31	0.122
LLD	5.20±2.67	6.03±3.10	t=-1.57	0.116
AL	0/65	0/59	-	-
PFF	0/65	0/59	-	-
PJI-Hip	o/65	o/59	-	-
IP-THA-D	o/65	o/59	-	-
PD-THA-D	1/65	3/59	z=-0.116	0.26

Typical cases

Case 1: A 87-year-old woman was admitted to the hospital with a fall injury that caused pain and limitation of movement of the right hip joint for 3 hours. Physical examination: the right hip was mildly swollen, the right lower limb was shortened and externally rotated deformity, deep pressure pain at the midpoint of the right groin (+), percussion pain of the right greater trochanter (+), and pain in the right hip caused by longitudinal percussion on the right heel, and the orthopantomogram and lateral orthopantomogram of the right hip: discontinuity of cortical continuity of the right femoral neck was seen and a clear fracture line could be seen, so she was diagnosed as having a fracture of the right femoral neck, and she was actively perfected with the preoperative examination. The right artificial femoral head replacement was performed under combined lumbar and rigid anesthesia within 48 hours after the injury. The operation went smoothly and the prosthesis was in good position, and the preoperative and postoperative imaging data are shown in Figure 4.

Case 2 The patient is an 86-year-old woman who was admitted to the hospital with a fall injury that caused pain and limitation of movement of the right hip joint for 6 hours. Specialized examination: active and passive activities of the right hip joint in all directions were severely limited by pain, and the right inguinal region was positive for deep pressure pain and longitudinal percussion pain. Imaging examination: orthopantomogram of the pelvis + orthopantomogram of the right hip: right femoral neck fracture, actively improve the preoperative examination, exclude contraindications to the operation on the third day after the injury under general anesthesia, the right artificial femoral head replacement, the surgical process went smoothly, the prosthesis position is good, the preoperative and postoperative imaging data are shown in Figure 5.

As the largest ball-and-socket joint in the human body, the hip joint serves not only weight-bearing functions but also provides a wide range of motion. The key to these functions lies in the maintenance of joint stability, which depends on the synergistic action of strong surrounding ligaments, muscular complexes, and the joint capsule. Therefore, the ability to maintain intraoperative soft tissue balance is a critical determinant of surgical success. In hip arthroplasty, minimizing soft tissue damage or effectively repairing damaged structures helps optimize postoperative hip function and reduces the risk of early dislocation [14,15]. The external rotator complex originates from various bony structures and inserts on the medial aspect of the greater trochanter. Its coordinated contraction produces external rotation by pulling the femur posteromedially. A normal hip typically allows 40°–60° of external rotation, which is essential for maintaining normal gait. Selecting an appropriate surgical approach can significantly improve the overall health and functional prognosis of elderly patients with femoral neck fractures [16].

The posterolateral approach, as the conventional surgical route for hemiarthroplasty, generally requires division and subsequent repair of all external rotators to obtain adequate surgical exposure and facilitate osteotomy and prosthesis placement. Traditional direct end-to-end suture repair is prone to failure during early postoperative activity. With technological advances, several repair strategies have emerged: posterolateral anchor fixation into the greater trochanter, figure-of-eight “hernia repair” suturing to the greater trochanter, and anatomical reconstruction of the external rotator group [17-19]. Additionally, some surgeons attempt to preserve portions of the external rotators—particularly the piriformis muscle—during surgery, which ensures successful procedure completion while yielding favorable clinical outcomes [20,21]. Huang et al. further noted that using a piriformis-sparing posterolateral approach for hemiarthroplasty can provide immediate postoperative stability and facilitate early functional exercise [22]. This suggests that current techniques for repairing the external rotators still have room for optimization, warranting in-depth research to refine techniques and select the optimal repair strategy.

Existing studies have confirmed that disruption of the short external rotators and joint capsule during total hip arthroplasty (THA) leads to an imbalance between dynamic and static hip stabilizers, thereby increasing dislocation risk [23-26]. In situ anatomical reconstruction of the divided short external rotators and joint capsule helps restore posterior soft tissue tension balance, provides stable longitudinal support for the prosthesis, and promotes more uniform stress distribution in the periarticular tissues. This not only enables patients to perform limited weight-bearing functional exercises earlier in the postoperative period and shortens rehabilitation time, but also effectively improves hip joint function .

Compared with other methods, the technique adopted in this study demonstrated significantly superior outcomes in terms of postoperative VAS scores, Harris Hip Scores, and hip range of motion (flexion-extension and internal-external rotation). Moreover, this technique aims to reconstruct the short external rotators in a manner that closely replicates the patient’s native anatomy, restoring the muscle force arms to a near-physiological preoperative state, thereby optimizing postoperative muscle strength recovery. To some extent, this approach may avoid the risk of avulsion fractures or rerupture due to altered biomechanics during repair. The tendon insertion is further secured in the piriformis fossa slightly inferior to the gluteus medius. The advantage of this design is that during early rehabilitation, contraction of the gluteus medius is less likely to exert direct traction on the repaired short external rotators, reducing the risk of secondary injury and accelerating recovery. Furthermore, the study results indicated that the experimental group had significantly less intraoperative blood loss and a shorter incision length than the control group. The primary reason for this is believed to be the maximal restoration of the native anatomical position, which reduces bleeding caused by bone drilling, extensive soft tissue dissection, and vascular injury.

Additionally, this technique provides greater early postoperative stability. The study showed that patients in the experimental group achieved full weight-bearing significantly earlier than those in the control group. Cemented hemiarthroplasty provided immediate stability through rigid fixation, enabling earlier functional activities and rehabilitation training. Preliminary observations suggest that this reconstruction method is suitable for patients with good preoperative hip function and without significant contracture of the short external rotators or joint capsule.

In situ anatomical reconstruction of the divided short external rotators and joint capsule helps restore posterior soft tissue tension balance, provides stable longitudinal support for the prosthesis, and promotes more uniform stress distribution in the surrounding tissues. This not only facilitates early restricted weight-bearing exercises and shortens the rehabilitation period but also effectively improves hip function [27].

Our findings indicate that the experimental group showed statistically significant advantages over the control group in intraoperative blood loss and incision length (reductions of 14 mL and 0.6 cm, respectively; p < 0.05). However, caution is warranted when interpreting whether these statistical differences translate into meaningful clinical benefits. First, a reduction of 14 mL in blood loss is minimal in the context of an adult’s total blood volume—typically accounting for less than 1%—and is unlikely to substantially influence hemodynamic stability, transfusion requirements, or postoperative recovery. Moreover, this margin may vary with intraoperative conditions. Therefore, such a minor reduction in blood loss does not by itself constitute a compelling rationale for selecting one surgical technique over the other. Second, although a 0.6 cm shorter incision may offer cosmetic benefits for some patients, its impact on postoperative pain, wound healing quality, or long-term aesthetic outcomes is likely limited. Previous studies have suggested that differences in incision length on the order of 1–2 cm may be necessary to yield clinically discernible differences. Therefore, the comparative evaluation of these two surgical techniques should be based on a comprehensive assessment of clinically relevant outcomes.

Compared with other methods, in situ anatomical reconstruction of the short external rotators and joint capsule using the technique adopted in this study offers greater advantages in promoting hip function recovery, enhancing muscle strength, and accelerating patient rehabilitation. This technique aims to restore the short external rotators to a configuration that closely resembles the native anatomy, allowing muscle lever arms to approximate the preoperative state and thereby optimizing postoperative muscle recovery. The tendon insertion is further fixed in the piriformis fossa slightly below the gluteus medius. This approach offers the advantage of reducing direct traction from the gluteus medius on the repaired short external rotators during early rehabilitation, thereby lowering the risk of secondary injury and speeding up recovery. In addition, the technique provides greater stability in the early postoperative period, allowing patients to begin functional activities and rehabilitation earlier.

Limitations

This study has several limitations. Its retrospective design introduces a potential for selection bias. Additionally, the maximum follow-up period of one year may be insufficient for evaluating long-term outcomes such as prosthetic loosening and late dislocation; extended follow-up is therefore planned to better assess long-term efficacy. Furthermore, in elderly patients with comorbidities, the presence of underlying medical conditions may influence intraoperative blood loss—a relationship that warrants further investigation. The method of group allocation may also have introduced subjective bias, and the absence of subgroup analyses limits the ability to identify specific patient populations most likely to benefit from the technique. Consequently, future large-scale, multicenter studies are needed to validate these preliminary findings and further elucidate the potential advantages of the procedure.

We believe that this muscular reconstruction technique, combined with intraoperative strengthening of the capsular repair, provides sufficient joint stability to stabilize the patient immediately after surgery. In hemiarthroplasty for displaced intracapsular fractures, anatomical bionic reconstruction not only guarantees joint stability, but also achieves a better functional prognosis, as evidenced by a better return of the patient's activity level to the pre-injury state than with conventional reconstruction methods.

HA Hemiarthroplasty；PLA Posterolateral Approach；BMI Body Mass Index;VAS Visual analogue scale；AV Anteversion Angle；ABD Abduction Angle；PFF Periprosthetic Femoral Fracture；PJI-Hip Periprosthetic Joint Infection of the Hip；IP-THA-D Inpatient Dislocation；PD-THA-D Post-Discharge Dislocation；LLD Limb Length Discrepancy；AL Aseptic Loosening

Funding: Not applicable.

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No competing interests reported.

The efficacy of anatomical biomimetic reconstruction of the external rotator muscle group combined with repair of the annular ligament in hip replacement surgery

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