Surgical technique: a simple technique for closing the capsule of the hip in posterolateral approach total hip arthroplasty (2025)

Background

Repair of the posterior soft tissue via a posterolateral approach following total hip arthroplasty has been reported to mitigate the risk of dislocation. The joint capsule serves as the primary protective barrier, and while previous techniques for closure have been predominantly complex, we present a novel, simplified technique for joint capsule closure.

Methods

A total of 215 patients who underwent primary THA via the posterolateral approach at our hospital from May 2018 to December 2022 were retrospectively enrolled in this study: 111 patients had their joint capsules sutured using traditional methods, while 114 patients had their joint capsules sutured using the new technology.

Results

Compared to the traditional suture group, the novel joint capsular suture group exhibited shorter operation times (p = 0.004) and reduced postoperative drainage volumes (p < 0.001). There were no significant differences in intraoperative blood loss, acetabular anteversion angle and abduction angle between the two groups. Although the Harris scores at 2 weeks, 3 months, and 6 months after surgery were marginally greater in the novel joint capsular suture group than in the traditional suture group, these differences did not reach statistical significance. Regarding adverse reactions observed during follow-up, hematoma occurred in seven patients (6.6%), and dislocation occurred in four patients (3.6%) in the traditional suture group; conversely, within the new joint capsule suture group, there were only two patients (1.8%) of hematoma with no instances of dislocation recorded thus far.

Conclusions

The preliminary results show that this new capsular closure technique allows the joint capsule to close more tightly and is an effective technique for reducing the rate of early postoperative dislocation.

The posterolateral approach has become the classic surgical approach in total hip arthroplasty because it involves clear exposure of the femur and acetabulum and can allow more accurate placement of the prosthesis. However, in the posterolateral approach, the external rotator muscle group, joint capsule and other structures need to be separated, which destroys the integrity and protection of the posterior soft tissue, which is an important reason for the greater dislocation rate in the posterolateral approach than in the anterolateral approach [1]. Some studies have reported that the incidence of posterior dislocation of the hip joint after THA via the posterolateral approach is 8%, while that after THA via the anterior approach is only 2% [2].

Historically, the earliest posterolateral approach was to remove the posterolateral joint capsule without suturing the external rotator muscle group, resulting in a lack of soft tissue restraint behind the hip in the early postoperative period [3], and new scar tissue needs to be formed to restrain the hip in the later period, which is why most dislocations occur in the early postoperative period [4, 5]. Currently, with changes in concept, the repair of posterior soft tissue has received increasing attention. The joint capsule is particularly critical as the first barrier to prevent dislocation. For decades, many senior orthopedic surgeons have proposed a variety of surgical techniques to repair posterior soft tissue damage during surgery, including the repair of the joint capsule. Based on the results, it seems that each technique reduces the risk of postoperative dislocation. However, most of these techniques are complicated or involve combining the joint capsule with the external rotator muscle group for suture fixation [6,7,8,9].

This article describes our novel, simple, fast and easy-to-master joint capsule closure technique. Our tests revealed that the joint capsule could close more tightly, thereby reducing the dislocation rate. In addition, the support for the idea of layering suturing of the posterior soft tissue is also presented.

Patients who underwent primary THA via the posterolateral approach at our hospital between May 2018 to December 2022 were retrospectively enrolled. Patients with developmental dysplasia of the hip (DDH), neurological disorders, or deficient hip musculature, or those who underwent bilateral THA simultaneously were excluded. Additionally, patients who did not complete the Harris scale before surgery or at 2 weeks, 3 months, or 6 months after surgery were also excluded. Ultimately, 22 patients with congenital dysplasia of the hip were excluded, and 5 patients who underwent simultaneous bilateral THA were excluded. Twenty patients were lost to follow-up during the postoperative Harris evaluation. A total of 215 patients were enrolled. Among them, the joint capsules of 111 patients were sutured via the traditional suture technique, and the joint capsules of 114 patients were sutured via a new technique. (Fig.1).

Surgical technique

All the operations were performed by P.T., who was a senior surgeon. All of the procedures were performed using the same type of cementless acetabular (Trilogy, Zimmer, Warsaw, Indiana) and femoral components (Fiber Metal Taper, Zimmer). The mean size of the acetabular component was 47mm (range 40–55mm), and ceramic prosthetic heads were used. All patients underwent surgery in a lateral position through a posterolateral approach. The skin, subcutaneous tissue and fascia lata were cut, the gluteus maximus muscle was bluntly separated, and the hip joint was exposed after an incision was made in part of the external rotator muscle group, while the piriformis muscle is preserved. The hip joint was exposed after the “T” incision. After the hip joint was dislocated, the soft tissue around the femoral neck was cleaned, the osteotomy distance was measured, the femoral head was removed, the acetabulum was polished, and the acetabular prosthesis and appropriate liner were placed. Then, the hip joint was flexed, adducted and externally rotated, and the femoral neck was lifted to fully expose the proximal femoral medullary cavity. After the medullary cavity was expanded to the appropriate size, the femoral prosthesis was placed, and the hip joint was reduced. After the X-ray images showed that the prosthesis was in good position, the incision was sutured and closed.

The procedure for the novel capsule suturing technique was as follows: The joint capsule was closed with a single 2-gauge Ethibond suture. The first needle passed through the broken ends of the joint capsule (Fig.2A). The second needle was passed through both stumps 1cm from the first needle’s exit point (in the opposite direction to the first needle); then, two fingers of one hand passed through the coil, and the other hand pinches the needle and the tail end of the thread (Figs.2B-C and 3-A). The coil is turned over to form two loops. The needle was cut off, the two ends of the thread were pinched through the two loops formed by the flip (Figs.2D-E and 3B), the two ends of the thread were pulled completely out, the ends were pulled tightly, and 5 surgical knots were tied (Fig.2F). For suturing the external rotator group, we used an attachment to the greater trochanter. The hip joint stability and the integrity of the posterior soft tissue repair were checked again, and the incision was closed layer by layer after the drainage tube was placed. In the traditional suture group, the joint capsule and the external rotator muscle group were also sutured by layers, but the joint capsule was sutured by simple interrupted suture.

Postoperative rehabilitation

All patients were treated with similar postoperative treatment and rehabilitation protocols. Symptomatic and supportive treatments, such as prevention of infection, prevention of thrombosis, and pain relief, were routinely performed. Postoperative dislocation prevention measures included the flexion of the affected hip joint not exceeding 90° for 3 months, such as the prohibition of sitting on a low stool or wearing socks. Within 3 months, the trapezoidal pad was placed between the knees while the patient rolled over to avoid excessive adduction and internal rotation of the hip. In addition, there were no restrictions on the patient’s weight.

Evaluation

The author (YY. J.), who was not involved in the operation, evaluated the patients with the Harris scale before surgery and 2 weeks, 3 months, and 6 months after surgery. We also reviewed the patients’ operation time, intraoperative blood loss, postoperative drainage volume, and postoperative adverse reactions.

Statistical analyses

The Kolmogorov‒Smirnov test was used to evaluate the normality of the distribution of the data. T tests were used to assess normally distributed continuous variables, which are expressed as the mean ± standard deviation. Categorical variables were compared using the chi-square test for between-group comparisons. SPSS statistical software (version 27.0, SPSS Inc., Armonk, New York) was used for all the statistical analyses. After statistical processing, the difference was statistically significant (p < 0.05).

Table 1 Summarizes the patient demographics. There were no significant differences in age, sex, or BMI between the two groups. Table2 summarizes the clinically observed outcome measures. The operation time was shorter (p = 0.004) and the postoperative drainage volume was lower (p < 0.001) in the novel capsular suture group than in the traditional suture group. There were no significant differences in intraoperative blood loss, acetabular anteversion angle and abduction angle between the two groups. The Harris scores at 2 weeks, 3 months, and 6 months after surgery were slightly greater in the novel capsular suture group than in the conventional suture group, but this difference did not reach statistical significance. In terms of adverse reactions, hematoma occurred in 7 patients (6.6%), and dislocation occurred in 4 patients (3.6%) in the traditional suture group. There were 2 patients (1.8%) with hematoma and no dislocation in the new capsule suture group

Regardless of the surgical approach, dislocation after hip replacement has an extremely negative impact on patients, with prolonged treatment and increased medical costs. In the posterolateral approach, postoperative dislocation is of particular concern. The idea that strengthening the repair of posterior soft tissue can reduce the occurrence of dislocation has gradually been recognized. Kwon et al. [10] reported that the relative dislocation risk of posterior soft tissue without repair was 8.21 times greater than that of soft tissue repair. A meta-analysis showed that posterior soft tissue repair resulted in lower dislocation rates and higher hip Harris scores than no repair [11]. Moon et al. [1] reported that ineffective posterior soft tissue repair was significantly associated with the occurrence of postoperative dislocation, and the relative risk of dislocation increased by 6.44 times after ineffective posterior soft tissue repair. Therefore, choosing a repair technique that can improve the success rate of posterior soft tissue repair is highly important for reducing the postoperative dislocation rate.

The posterior soft tissue of the hip joint is mainly divided into two layers: the joint capsule and the external rotator muscle. Some studies do not use layer-by-layer sutures. Browne et al. [6] reported the use of figural sutures to suture the external rotator muscle group and joint capsule to the gluteus minimus muscle, and 1 dislocation occurred in 178 patients, for a dislocation rate of 0.6%. Zhang et al. [12] used anchors to suture the external rotator muscle group and joint capsule to the greater trochanter, and no dislocation occurred in 220 patients. However, by drilling a hole in the greater trochanter, the joint capsule and the external rotator muscle group are sutured to the greater trochanter together, which is the suturing method reported in most studies at present [7, 8, 13, 14]. According to the study of Ko et al. [13], 28 cases of dislocation occurred among 1483 patients, for a dislocation rate of 1.89%. In the study of Kumar et al. [8], 4 out of 512 patients were dislocated, for a dislocation rate of 0.78%. In other studies, the two layers were sutured. Dixon et al. [15] sutured the joint capsule to the posterior edge of the gluteus medius tendon, and dislocation occurred in 1 out of 255 patients, for a dislocation rate of 0.6%. Tsai et al. [16] used a U-shaped incision to open the joint capsule, repaired the joint capsule to its original position after prosthesis placement, and then repaired the external rotator muscle group. There was no dislocation in 62 patients. Jurkutat et al. [17] also used layered sutures to close the posterior soft tissue structure, and dislocation occurred in 3 of 992 patients, for a dislocation rate of 0.3% (Table3).

According to our results, compared with traditional suturing, the new joint capsular suture technique has a better closure effect; reduces the postoperative drainage volume, dislocation rate and incidence of various adverse reactions; and does not increase the amount of intraoperative blood loss. At the same time, the operation time decreased, and the postoperative Harris score increased. This technique also has a lower dislocation rate than the previous suture technique. Compared with most of the previous complex suture techniques involving multiple steps, this technique is simple, quick and easy to learn and master. Furthermore, we preserved the piriformis muscle during surgery, as previous studies have demonstrated its role in enhancing hip stability [22–23]. At least half a year of follow-up, the new capsular suturing technique demonstrated good repair of the posterior soft tissue and reduced the incidence of serious consequences of hip dislocation. However, according to previous studies, dislocation mostly occurs within the first few months after surgery [24]. In addition, we performed a layered suture between the joint capsule and the external rotator muscle group. Compared with combined sutures, layered sutures are more conducive to the repair and healing of posterior soft tissue and reduce the dislocation rate [25], which has been proven by imaging evidence [26].

In conclusion, we believe that this new suture technique has a certain degree of reliability and is worthy of promotion. In addition, we will conduct a prospective trial of this technique in the future.

THA:

Total hip arthroplasty

DDH:

Developmental dysplasia of the hip

Author notes

1. Ruinan Chen and Yaoyu Jin contributed equally to this work and share first authorship.

Authors and Affiliations

1. The First Clinical College of Zhejiang Chinese Medical University, Hangzhou, 310053, China

   Ruinan Chen,Lei Chen&Penglei Chen

2. The First People’s Hospital of Longwan District, WenZhou, 325024, WenZhou, China

   Yaoyu Jin

3. The First Affiliated Hospital of Zhejiang Chinese Medical University (Zhejiang Hospital of Traditional Chinese Medicine), 54 Youdian Road, Hangzhou, Zhejiang Province, 310006, China

   Shuaijie Lyu,Peijian Tong&Xun Liu

Contributions

RN C and X L contributed to the study conception and design. RN C and YY J performed the data analysis and made significant contributions to the creation of figures and manuscript. All authors participated in data interpretation and manuscript revision. All the authors have read and approved the final manuscript.

Corresponding author

Correspondence to Xun Liu.

Ethics approval and consent to participate

All procedures performed in studies involving human participants were in accordance with the ethical standards of the institutional and national research committee and with the 1964 Helsinki declaration and its later amendments. The protocol of this study was approved by the Research Ethics Committee of Zhejiang University of Traditional Chinese Medicine First Affiliated Hospital. Owing to the retrospective nature of the study, a waiver of informed consent was granted.

Consent for publication

Not applicable.

Competing interests

The authors declare no competing interests.

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