Modified Stoppa Approach Alone or in Combination with a Lateral Window for Acetabular Fractures Involving Both Columns

Abstract

Purpose

Complex acetabular fractures involving both columns often require two approaches, one anterior and other posterior, for adequate reduction and fixation. Treatment of such fractures using modified Stoppa approach (MSA) either alone or in combination with lateral window of the ilio-inguinal approach has been reported. Whether this line of management is appropriate or not is a matter of further investigation. This study presents the clinical and radiological outcomes of acetabular both-column fractures using this approach.

Materials and Methods

Forty-one patients treated with MSA for anterior column with posterior hemi transverse (AC with PHT), associated both columns, T-type, and transverse fractures were postoperatively assessed at a minimum of one year. Their immediate postoperative reduction quality, as well as the clinical, radiological, and functional outcomes at the most recent follow-up visit were reviewed.

Results

Most patients were young males injured in motor vehicle accidents who underwent surgery after a mean delay of 4.8 days. The mean surgical time was 122.44 minutes, and mean blood loss was 413.41 mL. AC with PHT fracture was the most common. In 78.0% of cases, anatomical reduction was achieved. At one year, excellent radiologic, clinical, and functional outcomes were observed in 78.0%, 51.2%, and 73.2% patients, respectively. There were eight cases with major complications.

Conclusion

Using the MSA with satisfactory short-term results, it was possible to address acetabular fractures involving both the anterior and posterior elements in a select group of patients. A pelvi-acetabular surgeon should have expertise in using multiple surgical approaches including the MSA.

INTRODUCTION

Anatomical reduction and stable fixation are required for displaced acetabular fractures^1-3). Many surgical approaches have been described previously, but the choice is based on the pattern of fracture, direction of displacement, skin condition at incision site, and duration since injury^2-4). The best means of choosing an approach is to obtain the best possible visualisation of the fracture with adequate space for use of instruments and implant placement with minimum collateral damage^1-4).

The Kocher Langenbeck approach is considered the workhorse for fractures that need to be addressed posteriorly, such as those fractures where the posterior structures of the acetabulum are fractured and displaced. The ilioinguinal (IL) approach is often used for the fixation of fractures involving the anterior structures¹⁾. However, these two approaches need to be performed together at times, either in the same or different anesthetic settings, for adequate and appropriate reduction and fixation of acetabular fractures⁴⁾.

Rives et al.⁵⁾ and Stoppa et al.⁶⁾ described an anterior suprapubic approach that they utilized for performing mesh repair of recurrent inguinal hernias. Cole and Bolhofner⁷⁾, and Hirvensalo et al.⁸⁾ used a modification of the approach described by Stoppa et al.⁶⁾, for approaching and fixing acetabular fractures via an intrapelvic but extraperitoneal route. This is an anterior approach and provides visualization of fractures involving the quadrilateral plate. From inside the pelvic cavity, further visualization is possible up to the posterior column⁹⁾. Currently, this modified Stoppa approach (MSA) is used for fixation of acetabular fractures such as anterior column with posterior hemi transverse (AC with PHT), both-column, and T-type. Reducing the probability of intraoperative complications, the MSA avoids the middle window of the IL approach. For high anterior column and iliac blade fractures, an additional lateral window of the IL approach must be created. A few studies have been published reporting the results of similar cases treated surgically by MSA^10-17).

This study aimed to examine the hypothesis that in suitably identified fracture types, the MSA would be adequate to obtain satisfactory results and outcomes. The clinical and radiological outcomes were assessed in patients with both-column, AC with PHT, and T-type acetabular fractures. Using the MSA, both the anterior and posterior components were fixed in these select patients. Matta’s system for radiological outcome, Harris hip score (HHS) and Merle d’Aubigné scores were used for assessment.

MATERIALS AND METHODS

The prospective observational study was performed at SMS Medical College, Jaipur, India from February 2021 to December 2023 after obtaining SMS Medical College’s Institutional Review Board approval (No. 488/MC/EC/2021). Only patients aged 18 to 65 years who had a T-type fracture, anterior wall/column plus posterior hemi-transverse fracture, or both-column fracture, and were treated surgically using the MSA were considered for enrolment. Those who provided consent were included. Study exclusions included patients who required a separate posterior approach, had a head injury or major abdominothoracic injuries, had medical conditions necessitating the surgery to be deferred for more than 14 days, and those who didn’t provide consent or later withdrew consent.

Plain radiographs (antero-posterior and Judet views) were obtained during the pre-operative period. Computed tomography (CT) scans were obtained for fracture classification and planning the steps of fixation. Patients underwent surgery on a radiolucent operating table. The type of anaesthesia used was determined at the discretion of the anesthesiologists. Antibiotics for surgical prophylaxis was administered and, prior to prepping and draping, an indwelling Foley catheter was placed. The operating surgeon stood on the side opposite the fracture and made a vertical midline incision from 2 cm below the umbilicus to 1 cm above the symphysis pubis. The anterior rectus abdominis fascia was cut and the rectus abdominis was split in the midline. Blunt dissection was then performed to reach the retroperitoneal space. Using a malleable retractor, the bladder was mobilised away from the field. The periosteum and iliopectineal fascia were released from the superior pubic ramus. The corona mortis was explored and then either tied or cauterised. Using a retractor, external iliac vessels were identified, elevated, and protected along with the iliopsoas muscle. Surgical exposure continued posteriorly along the pelvic brim up to the sacroiliac joint. The obturator neurovascular bundle was identified in the fat on the medial surface of obturator internus muscle. It was then dissected and mobilized with a retractor.

Placement of a Schanz screw on a T-handle in the proximal femur was used for fracture reduction by lateral traction and indirect manipulation. An additional lateral iliac window was created for fractures with high anterior column involvement. This additional window allowed us to reduce and fix the anterior column as well as allowed for placement of reduction clamps or Schanz screws for reduction maneuvers. Depending on the fracture pattern and the available working space, the quadrilateral plate was reduced utilizing a modified Weber clamp, Cobb elevator or ball tipped spike pusher. Internal fixation was done after reduction with curved plates placed perpendicular to the fracture along the iliopectineal line and quadrilateral plate. Interfragmentary screws were used as required. Based on the fracture configuration and the extent of reduction achieved, the posterior column was fixed with either screws or a plate (Fig. 1-3).

Fig. 1.

Anteroposterior and iliac views of a patient showing the fixation of both the anterior and posterior column with reconstruction plates.

Fig. 2.

Radiographs showing the fixation of the anterior column and the quadrilateral plate with reconstruction plate and the posterior column with an interfragmentary screw.

Fig. 3.

A 22-year-old male patient suffered a T-type acetabular fracture following a vehicular accident. (A) Anteroposterior radiograph. (B) Computed tomography (CT) with three-dimensional reconstruction. (C) Axial CT image. This patient underwent surgery by modified Stoppa approach only. (D) Application of posterior column plate through the approach (arrow A) and two plates for anterior column fixation (arrow B). (E, F) Intraoperative image intensifier images of the same.

Bed-side mobilization was initiated from the first postoperative day. After the third postoperative day, strict non-weight bearing ambulation was allowed using a pair of axillary crutches or walker. Ankle and knee range of motion exercises were encouraged. Patients were kept non-weight bearing for the first six weeks. Partial weight bearing was permitted after signs of fracture consolidation were confirmed on radiographs. Radiographs were obtained during the immediate postoperative period, at six weeks and then monthly until union was achieved. After radiological union, each patient was followed up both clinically and radiologically every three months up to one year after surgery. Afterwards, they were followed up annually. Demographic details, mode of injury, fracture type, operating time and the estimated blood loss were recorded. Quality of the reduction was assessed on the immediate postoperative radiograph. Merle d’Aubigné score, HHS, and radiographic outcome (Matta criteria) were assessed during the most recent follow-up visit which was conducted at a minimum of one year after surgery. Using Matta’s system for assessment of radiological outcomes, the lowest of the three scores was considered as the grade for that case. Next, the collected data was entered in a Microsoft Office 2024 Excel spreadsheet (Microsoft) and analyzed using IBM SPSS Statistics (ver. 25; IBM Corp.). Descriptive statistics and mean values were used to report the results. An independent sample t-test was used to determine statistical significance.

RESULTS

Forty-seven patients were considered for study enrolment. Forty-one patients fulfilled the criteria for inclusion in this study. Of these patients, 44.78% were aged between 21 and 30 years. The mean age was 33.17 years. The majority of patients were male (73.2%). Table 1 displays the demographic characteristics of study participants. The reduction quality in immediate postoperative radiographs was within 1 mm (anatomical reduction) in 32 patients. However, it was incongruent in three patients. Table 2 presents the details related to reduction quality as well as the radiological and clinical outcomes at one year after surgery. The radiological grading was noted to be excellent in 32 patients at one year. While the HHS was excellent in 30 patients, the clinical outcomes based on the Merle d’Aubigné score was excellent in 21 patients. A statistically significant association (P<0.001) between the immediate postoperative reduction quality, and Merle d’Aubigné score, and HHS was obtained.

Table 1.

Demographic Characteristics of Study Participants

Variable	Value
Mean age (yr)	33.17 (18-65)
Sex, male:female	30:11 (73.2:26.8)
Mode of injury
Road traffic accident	32 (78.0)
Fall from height	8 (19.5)
Fall heavy object	1 (2.4)
Mean surgical delay (interval between injury and surgery) (day)	4.8 (4-8)
Fracture type
AC with PHT	20 (48.8)
Both column	15 (36.6)
T-type	6 (14.6)
Mean operative time (min)	122.44 (90-180)
Mean blood loss (mL)	413.41 (320-580)

Values are presented as mean (range) or number (%).

AC with PHT: anterior column with posterior hemi transverse.

Table 2.

Outcome Measures Assessed in This Study

Variable	Results
Quality of reduction on immediate postoperative radiographs
Anatomical reduction (≤1 mm)	32 (78.0)
Congruent reduction (>1 to <3 mm)	6 (14.6)
Incongruent reduction (≥3 mm)	3 (7.3)
Radiological grading by Matta’s method (after one year of surgery)
Excellent	32 (78.0)
Good	5 (12.2)
Fair	2 (4.9)
Poor	2 (4.9)
Clinical grading by Merle d’Aubigné hip score (after one year of surgery)
Excellent	21 (51.2)
Very Good	12 (29.3)
Good	4 (9.8)
Fair	2 (4.9)
Poor	2 (4.9)
Functional outcome using the Harris hip score (after one year of surgery)
Excellent	30 (73.2)
Good	5 (12.2)
Fair	3 (7.3)
Poor	3 (7.3)

Values are presented as number (%).

Table 3 details the complications encountered during treatment. During surgery, two patients suffered iatrogenic external iliac vein injury, which was subsequently repaired by the cardiovascular team. Three patients suffered iatrogenic obturator nerve injury noted in the postoperative period. Fortunately, all resolved spontaneously by five months after surgery. Three patients had serous discharge from the incision site without any other systemic features of infection. They were diagnosed with superficial surgical site infection and treated with antibiotics.

Table 3.

Complications Encountered during the Follow-up Period

Variable	Results
External iliac vein injury	2 (4.9)
Surgical site infection	3 (7.3)
Obturator nerve palsy	3 (7.3)

Values are presented as number (%).

DISCUSSION

Operative acetabular fracture management is technically challenging, especially in cases with both anterior and posterior involvement of the acetabular structures. This can be attributed to the complex anatomy, difficult approaches, proximity of vital vascular and neural structures, and limited availability of normal bony surface for implant placement and fixation. Extensile approaches, such as the extended iliofemoral and IL approaches, provide access to the anterior aspect of the acetabulum. When these approaches are combined with the Kocher Langenbeck approach, they provide adequate access for the fixation of complex fractures involving both the anterior and posterior structures. These combined approaches can be performed in the same or different anesthetic sittings¹⁸⁾. However, such approaches can be accompanied by complications, including increased probability of wound infection, vascular injury, neurologic injury, and blood loss^1,2,10,19). The MSA has a few advantages over the extensile approaches. The MSA avoids dissection of the middle neurovascular window of the classical IL approach and allows for direct visualization of the pelvis from the pubic body anteriorly to the sacroiliac joint posteriorly^7-10).

Sagi et al.¹⁰⁾ stated that when “executed correctly, the modified Rives-Stoppa approach provides access to the pubic body, superior ramus, pubic root, ilium above and below the pectineal line, quadrilateral plate, the medial aspect of the posterior column, the sciatic buttress, and the anterior sacroiliac joint.” The anastomoses between the external iliac artery and the obturator artery are well visualized allowing for better control of the hemostasis. After being initially described approximately thirty years ago, the MSA has been adopted by an increasing number of surgeons.

Many studies on the use of MSA have been published in recent years. The majority of them have studied general parameters like gender (sex), age, mode of injury, injury to surgery interval, surgical duration, and estimated blood loss. Immediate postoperative radiographs have been used to assess the quality of reduction and, the radiological criteria of Matta, Merle d’Aubigné score and HHS for were used in the outcome assessment. This relative uniformity across the studies allows for an objective comparison of results. Many studies have presented results in which surgeons have used the MSA for fixation of the anterior column fractures, and as a component of combined approaches for comprehensive acetabular fracture fixation^{7,10,12,15,17)}. While they do provide a comprehensive results, in our opinion this clubbing together of relatively simple fractures like isolated anterior column and wall, and of severe fractures that cannot be fixed without an additional posterior approach in the same study has the potential to skew the results. In the first category of cases, surgical duration, estimated blood loss, and immediate postoperative reduction quality is expected to be much better than those in the second category. However, neither category reflects the actual results of those cases that have involvement of both the anterior and posterior acetabular components and are amenable to being managed by MSA.

Important inferences drawn from this study include treatment of a younger (mean age, 33.17 years), predominantly male (M:F ratio of 2.7:1) patient population injured in road traffic accidents (RTA) (78.0% cases) who underwent surgery with a mean delay of 4.8 days between the injury and the surgery. These parameters are similar throughout the literature published and reflect the trend of young males involved in high velocity motor vehicle accidents, irrespective of their nationality. Furthermore, the mean delay period is similar, which we believe is due to the mean time needed by patients with these life-threatening injuries to become fit for undergoing major surgical procedures.

In our study, mean estimated blood loss was 413.41± 48.14 mL, and mean surgical duration was 122.44±19.72 minutes. While mean surgical duration was similar to that reported by other surgeons, estimated blood loss was on the lower side when compared to other studies. Our study had 20 patients with an AC with PHT (48.8%), 15 patients with associated both-column (36.6%), and 6 patients with T-type fractures (14.6%). Thus, AC with PHT was the most common fracture type observed. Jakob et al.²⁰⁾ also reported this concurrent finding. In contrast, Sagi et al.¹⁰⁾, Kilinc et al.¹⁴⁾, Singh et al.¹⁵⁾, Salama et al.¹⁶⁾, Çağlar et al.²¹⁾, and Verbeek et al.²²⁾ have all found associated both-column fractures to be the most common pattern in their respective series. While it is difficult to identify or postulate the cause, most patients with AC with PHT fractures were involved in roadside accidents involving two wheelers. Further investigations should focus on whether the type of automobile involved in the RTA factors into the resulting fracture pattern.

While our team always fixed the anterior column and the quadrilateral plate with plates, the posterior column was fixed with a plate in 25 patients and with interfragmentary screws in 16 patients. One patient needed an additional iliac wing plate. Thus, an additional lateral window had to be made in 17 patients for either a posterior column screw or the iliac blade plating. This combined use of a lateral window with the MSA has been termed by Rocca et al.²³⁾ as the anterior combined endopelvic (ACE) approach. The ACE approach was highly recommended when the fracture involved the quadrilateral surface and anterior column. Yang et al.²⁴⁾ retrospectively, studied 57 patients in whom a similar approach was used. They termed it a modified Stoppa combined with an iliac fossa approach. Yang et al.²⁴⁾ also concluded that such an approach can achieve satisfactory reduction quality and hip function and might be a valuable alternative to the IL approach for the surgical acetabular fracture management.

This study found that the reduction quality was anatomical in 78.0%, congruent in 14.6%, and incongruent in 7.3%. Incongruent reduction was seen in two patients with AC with PHT fractures, and one with both-column fractures. Both patients with AC with PHT fractures were more than 60 years old and had dome impaction. Dome impactions may be difficult to reduce and fix, especially in the older patients with osteoporotic bones. While Singh et al.¹⁵⁾ reported an 86.6% anatomic reduction rate, almost all other studies have reported an anatomical reduction rate in approximately 50% to 70% of the cases.

When surgical outcomes at one year are considered, we found excellent, good, fair, and poor scores as per Matta’s system in 78.0%, 12.2%, 4.9%, and 4.9% cases, respectively. Excellent outcomes were reported by Singh et al.¹⁵⁾ in 80% of cases, by Isaacson et al.¹¹⁾ in 75% of cases, and Sagi et al.¹⁰⁾ in 92% of cases. Thus, most studies show excellent and good radiological outcomes by the MSA. In this series, a statistically significant correlation was observed between the initial reduction quality and Matta’s score (P<0.001). The Merle d’Aubigné score and HHS scores were excellent in 51.2% and 73.2% of patients in our study. Moreover, all other studies we reviewed have noted a similar excellent rates. Notably, these scores also correlate well with the initial reduction quality and with the Matta radiological scores. It can thus be inferred that the initial reconstruction is a deciding factor as to how well a joint will function, provided other factors have minimal influence. At one year follow-up, six patients had developed arthritic changes. They had poor HHS and Merle d’Aubigné scores.

Our reported complications have previously been reported by other surgeons^10-17,21). A total of eight major complications related to the surgical exposure and procedure were noted—external iliac vein injury in two cases, obturator nerve injury in three cases, and surgical site infection in three cases. Injury frequency was no more than that previously reported in the literature.

When the surgical delay, blood loss, surgical time, HHS were used to study the follow-up clinical grading (P=0.58, 0.45, 0.38, 0.43, and 0.35, respectively), we found no statistically significant differences during our evaluation for any association of different variables with the clinical outcomes. In our study, the mean values of HHS were 92.84, 80.83, and 6.35 for anatomical reduction, congruent reduction, and incongruent reduction, respectively. A statistically significant difference was observed among the groups with ANOVA and post hoc analysis. The mean values of the Merle d’Aubigné score were 17.63 in anatomical reduction, 15.33 in congruent reduction, and 13.33 in incongruent reduction. The relationship between reduction quality and clinical outcomes was found to be statistically significant (P<0.001).

Notably, there are a few important limitations of this study. While the sample size of 41 is not very small, minimum follow-up duration for reporting was limited to one year which is most likely an inadequate length of time to report on long-term outcomes. Ideally, a larger number of patients with a longer follow-up period would have been better as an injured acetabular cavity can lead to arthritic changes later. Given that by one year we tend to see arthritic changes in cases of unsatisfactory reduction, we believe this short term follow-up period provided a snapshot of the hip status. Reduction quality was assessed on radiographs and not by CT scan. While CT would be the ideal investigation to measure the fracture gap accurately in the postoperative period, in most cases we could not obtain it due to cost constraints of patients who were paying out of pocket. As most patients did not have CT scans, CTs were not used for analysis. There was no comparison group in this study. A randomized trial having treatment by the MSA approach as one arm of study, and a combined approach as the second arm would have been ideal. However, given that, at present, most cases requiring an anterior approach to the fracture are being surgically treated by us using the MSA, having a comparison group was impractical.

CONCLUSION

Despite the previously described limitations, results obtained in this study do support the use of the MSA for addressing all of the components of selected acetabular fractures. While it is at the surgeon’s discretion to decide if a single approach (the MSA) is used for these fractures or not, a trauma surgeon caring for patients with acetabular fractures must be well versed in this approach.

Funding Statement

Funding No funding to declare.