The quadrilateral surface, as the medial wall of the acetabulum, may be damaged easily with less force because of its relatively minimal bone stock.1 For fractures of this area, open reduction and internal fixation are the preconditions of a functional outcome.2–4 However, it is challenging to obtain reduction of the fractures through the traditional ilioinguinal and/or Kocher–Langenbeck approaches.5,6
The Stoppa approach, originally used for hernia repair, offers direct access to and visualization of both the quadrilateral surface and the medial aspect of the posterior column from the ischial spine to the greater sciatic notch.7–12 With the surgeon standing at the contralateral side, reduction and fixation of displaced fractures can be obtained through the Stoppa approach.13 Compared with the ilioinguinal or the Kocher–Langenbeck approach, a lower complication rate can be gained through the minimally invasive Stoppa approach.6,14 Thus, it has been widely employed to manage pelvic and acetabular fractures.13,14 Shazar et al15 reported that a better quality of reduction of displaced acetabular fractures could be gained through the Stoppa approach.
However, it is challenging to gain adequate stability with conventional reconstruction plates or lag screws for a quadrilateral surface involving comminuted or free-floating medial wall fragments.16 The authors' team designed a type of anatomic quadrilateral surface plate (AQSP) to accomplish the satisfactory fixation of displaced quadrilateral surface fractures (Figure 1). The purpose of this study was to assess the therapeutic effect of the AQSP through the Stoppa approach for displaced fractures of the quadrilateral surface.
Three combined holes (arrows) in the anatomic quadrilateral surface plate (A). The region for placement of the anatomic quadrilateral surface plate is shown (B).
Materials and Methods
Informed consent was obtained from each patient. All of the work, including the surgical methods and review, was performed in accordance with the guidelines approved by the institutional review board of the participating institution. Patients admitted to the authors' institution for displaced fractures involving the quadrilateral surface from February 2014 to February 2015 were reviewed. Inclusion criteria were as follows: closed unilateral acetabular fracture fixed with an AQSP through the Stoppa approach, age 18 to 65 years, no other injury (including injury of the brain or stomach), and a normal activity ability before the injury. The exclusion criteria were as follows: pathological fracture, open fracture, fracture involving other areas besides the pelvis, other risk factors affecting bone healing (eg, smoking, osteoporosis, metabolic diseases), and noncompletion of the 2-year follow-up.
In this study, all surgical procedures were performed by the same team, and all of the surgeons had more than 5 years of experience in acetabular surgery. The surgical procedures were performed in the supine decubitus and flexed position of the ipsilateral hip, which was maintained throughout the procedures to relax the tension of the femoral neurovascular bundle. A transverse or longitudinal skin incision was performed in the region 1 to 2 cm superior to the pubic symphysis. Then, a longitudinal split of the linea alba (the junction of the bilateral rectus fibers) was performed to expose the retropubic space. Both edges of the incision and the bladder were covered with a layer of gauze to decrease the incidence of iatrogenic injury. Separation of soft tissues, including the obturator vessels and muscles, was conducted to expose the pelvic ring and the quadrilateral surface. The insertion of the rectus in the lateral and anterior pubic body was partially released to lower the tension of the muscle. A straight retractor, which can also play an important role in the reduction of posterior detached fragments, was placed at the edge of the posterior fragment to obtain better exposure of the quadrilateral surface (Figure 2). In addition, the placement of a straight retractor may be helpful to avoid injury of the bladder during the drilling.
Location of placement of the straight retractor (A). Intraoperative application of the straight retractor (arrow) (B).
For the medially displaced fragments, an outward push force generated by a ball-spiked pusher and the distal traction of the lower limb were indispensable to obtaining reduction. Taking both-column fractures as an example, the fixed posterior iliac fragment, anteromedially displaced iliopubic fragment, and medially displaced ischial fragment were always observed (Figure 3A). With a continuing traction force on the lower limb, the reduction of the iliopubic fragment was obtained through the iliac fossa approach. Then, the medial displacement was reduced with an outward force from a ball-spiked pusher through the Stoppa approach (Figure 3B). The anterior and/or posterior displaced fragments were reduced with reduction forceps (Figures 3C–D). Once the reduction was achieved, a 2.5-mm K-wire was inserted cephalad to accomplish the temporary fixation of the fragments of the quadrilateral surface (Figure 4A). The K-wire also served as a “slide ladder” for the placement of the AQSP (Figure 4B). The AQSP, which was provisionally fixed to the medial aspect of the quadrilateral surface with the use of a ball-spiked pusher, was placed in the space between the obturator neurovascular bundle and the quadrilateral surface (Figure 4C). Finally, the screws were inserted to fix the main displaced fragments (Figures 4D–F). To reduce the rate of penetration into the hip joint, the screws were not inserted at the middle 3 holes of the plate. The obturator neurovascular bundle should be dissected and gently retracted medially to avoid oppressive injury when the AQSP is implanted. Careful attention was paid during the drilling near the sciatic spine to avoid iatrogenic injury of the sciatic nerve. Negative pressure drainage and suturing of the surgical incision were conducted after the reduction and fixation of the displaced fragments.
The reduction procedure for quadrilateral surface fragments in both-column fractures. The fixed posterior iliac fragment (I), anteromedi-ally displaced iliopubic fragment (II), and medially displaced ischial fragment (III) could be observed in both-column fractures (A). The outward push force on the quadrilateral surface was generated by a ball-spiked pusher (B). Application of the reduction forceps (C, D).
Surgical technique for placement of the anatomic quadrilateral surface plate. A 2.5-mm K-wire was inserted cephalad to accomplish the temporary fixation of fragments (A). The plate was placed with a “slide ladder” technique (B). There were 3 combined holes (arrows) in the anatomic quadrilateral surface plate. The plate was provisionally fixed with a K-wire and a ball-spiked pusher (C). The screws were inserted (D–F).
Twenty-four–hour antibiotic treatment was routinely administered to prevent wound infection. Active exercise of the ipsilateral hip joint was encouraged to avoid ankylosis. Follow-up was performed postoperatively at 1, 2, and 3 months and then every 3 months thereafter. Therapy and rehabilitation exercise were tailored according to the clinical and radiological results acquired at each follow-up visit. Full weight-bearing training began when the fracture line disappeared on the anteroposterior and Judet projections at follow-up.
Outcome Measures and Statistical Analysis
Operative time, intraoperative blood loss, quality of reduction, and healing of the fracture were recorded. The quality of reduction was assessed by postoperative radiograph and computed tomography scan according to the criteria described by Matta.17 Fracture healing was assessed on the radiographs performed at each follow-up visit. Nonunion was defined as a fracture line that had not completely disappeared within 9 months and had not shown further progression to healing during 3 consecutive months. The functional evaluation was done with the Merle d'Aubigné score at the final follow-up visit. Statistical data were processed using SPSS version 23.0 software (SPSS, Chicago, Illinois). The metrological continuous data were presented as mean±standard deviation.
Thirty-two patients received the AQSP fixation. Six patients were excluded for the following reasons: lost to follow-up (n=3), osteoporosis (n=1), and other injury (n=2). Twenty-six patients met the study inclusion criteria. There were 16 men and 10 women with a mean age of 37.5 years. There were 4 anterior column, 6 transverse, 5 anterior column and posterior hemitransverse, 4 T-shaped, and 7 both-column fractures (Table 1). The patients were followed for a mean of 28.81 months (range, 24–36 months). The mean operative time was 98.85±16.08 minutes, and the mean intraoperative blood loss was 353.85±124.84 mL. Anatomic reduction (<1 mm) was obtained in 23 patients (88.46%), and good reduction (1 to 3 mm) was obtained in 3 patients (11.54%). Poor reduction was not observed. All of the fractures healed well at a mean of 3.54 months. The mean Merle d'Aubigné score was 16.38±1.33 points at final follow-up. Intraoperative injury of the obturator nerve occurred in 2 patients, and the adduction weakness of their affected thigh resolved after 2 months of conservative treatment. Corona mortis injury occurred in a case during the exposure of fracture, and timely ligation was conducted to avoid uncontrolled bleeding. Permanent complications were not observed during follow-up.
The quadrilateral surface is the medial wall of the acetabulum, and its detachment is always caused by medial impact from the femoral head. Qureshi et al18 found that the displacement of the quadrilateral surface occurred in 10% to 15% of acetabular fractures. However, it was not regarded as a parameter in the gold standard Judet–Letournel classification system.19
The fractures of the quadrilateral surface are frequently associated with anterior column and posterior hemitransverse, both-column, transverse, posterior column, and/or T-shaped fractures.18,20 Most surgeons believe that operative management is indispensable to obtain the functional outcome for displaced acetabular fractures.4,21,22 The quality of reduction and fixation plays an important role in the ultimate outcome.17,23 Prasartritha et al5 used 3-dimensional computed tomography to study the broken quadrilateral surface, finding that its integrity was essential to maintaining the stability of the acetabulum. Although there has been much progress in treatment during the past few years, the management of quadrilateral surface fractures remains challenging.16,18
For patients with an adequate space for the ligamentum teres within a functioning hip, weight-bearing of the medial wall may be unnecessary. However, traumatic arthritis, which is caused by mismatching of the acetabular fossa and the femoral head, would be involved in the long-term rehabilitation process. Further, protrusio will ensue if the bone is weak in the relevant area. Thus, anatomic reduction and firm internal fixation for the medial wall is essential for most acetabular fractures.3,22,24 In the past, quadrilateral surface fractures involving both the anterior and the posterior columns were always stabilized with reconstruction plates through combined (ilioinguinal and Kocher–Langenbeck) approaches.25,26 Regarding the acetabulum as a “bowl,” only sidewalls could be fixed through conventional combined approaches. The bottom of the bowl could be exposed and fixed directly through the Stoppa approach, which was thus preferred in the treatment of displaced quadrilateral surface fractures (Figure 5). However, sufficient stability was difficult to gain through conventional fixation methods. Serious complications, including screw loosening and secondary displacement, may occur due to an insufficient buttress fixation or inadequate stability of displaced fragments (Figure 6).20,27,28
The red, blue, and green lines (arrows) indicate the regions that could be fixed with reconstruction plates through the ilioinguinal, Kocher–Langenbeck, and Stoppa approaches, respectively. A “bowl” representing the acetabulum (A). Computed tomography scan of the fractures of the quadrilateral surface (B).
The fixation failure of conventional techniques. A case of anterior column and posterior hemitransverse fracture fixed with plates and a lag screw through the ilioinguinal and Kocher–Langenbeck approaches. However, secondary detachment occurred in the rehabilitation process (A, B). Insufficient buttress fixation (arrows) for the quadrilateral surface with a conventional plate in a case of anterior column and posterior hemitransverse fracture (C, D).
In addition, it was indispensable to reshape the conventional plates repeatedly because of the specific anatomy of the quadrilateral surface, which would prolong the operative time and lower the buttress intensity of the plates.29 Furthermore, combined approaches may lead to a high rate of intraoperative complications. Antero-grade lag screws might be inserted from an anterior approach to fix the posterior column, and the posterior incision may thus be avoided. However, lag screws provided less stability of the fragments, and the insertion technique was demanding.30,31
For the fracture line involving the ilium, a lateral window of the ilioinguinal approach was added. Some intraoperative techniques for reduction and fixation have been presented in this study. The intact greater sciatic notch could serve as a reference mark for the reduction of displaced fragments. The entry point of the K-wire was a crucial issue in the surgical procedure because it determined the location of the AQSP. There were 3 combined holes in the AQSP (Figure 1), which could generate a compressive effect on the plate and the quadrilateral surface. In addition, the designed drilling directions of the locking hole could reduce the risk of screw penetration into the hip joint. Repeated precontouring was avoided for the patients fixed with the AQSP because of its specific shape. Additionally, sufficient stability of the quadrilateral surface could be obtained with the AQSP because of its excellent buttress effect. Thus, the AQSP has been widely employed to manage displaced fractures of the quadrilateral surface, and no failure of fixation was observed in this study (Figures 7–8).
Anterior column fracture fixed with the anatomic quadrilateral surface plate. Preoperative anteroposterior projection (A). Preoperative computed tomography scans (B–D). Preoperative 3-dimensional reconstruction (E). Surgical incision (F). Postoperative anteroposterior and Judet views (G–I). Postoperative computed tomography scans (J, K). Anteroposterior view at the 1-year follow-up (L).
Both-column fracture fixed with the anatomic quadrilateral surface plate. Preoperative antero-posterior and Judet views (A–C). Preoperative computed tomography scans (D, E). Postoperative anteroposterior and Judet views (F–H). Postoperative computed tomography scans (I, J). Anteroposterior projection on 6-month follow-up (K). Anteroposterior view at 1-year follow-up (L).
Compared with reconstruction plates through combined approaches, the blood loss and complication rate could be lower with the AQSP through the Stoppa approach because of its less invasive incision. However, iatrogenic injury of the obturator nerve bundle and corona mortis may accompany placement of the AQSP because it is much larger than the conventional plate. Because timely ligation of the corona mortis and standardized postoperative physical therapy for the obturator nerve injury were performed, permanent complications were avoided in this study.
This study had some limitations. There were a limited number of patients and no control group treated with conventional fixation methods. These factors may restrict the clinical popularity of the AQSP to some degree. However, because of its excellent fixation effect, fixation of the AQSP through the Stoppa approach could serve as a minimally invasive treatment for quadrilateral surface fractures. To further explore the feasibility of the AQSP for acetabular quadrilateral surface fractures, additional patients receiving fixation with conventional plates through various approaches (including ilioinguinal and/or Kocher–Langenbeck) should be recruited as controls.
Satisfactory fixation effect and functional outcome of displaced quadrilateral surface fragments could be obtained with an AQSP through the minimally invasive Stoppa approach.
- Laflamme GY, Delisle J, Leduc S, Uzel PA. Isolated quadrilateral plate fracture: an unusual acetabular fracture. Can J Surg. 2009;52(5):E217–E219.
- Judet R, Judet J, Letournel E. Fractures of the acetabulum: classification and surgical approaches for open reduction. Preliminary report. J Bone Joint Surg Am. 1964;46:1615–1646. doi:10.2106/00004623-196446080-00001 [CrossRef]
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|Patient No./Sex/Age, y||Fracture Type||Blood Loss, mL||Operative Time, min||Reduction Quality||Follow-up, mo||Time to Union, mo||Merle d'Aubigné Score, points||Complication|
|4/M/45||Anterior column||350||70||Good||28||2||16||Corona mortis injury|
|7/M/40||Anterior column and posterior hemitransverse||350||80||Anatomic||34||4||18||NR|
|9/M/36||Transverse||300||95||Anatomic||26||3||14||Obturator nerve injury|
|11/F/34||Anterior column and posterior hemitransverse||350||100||Anatomic||25||4||16||NR|
|13/F/45||Anterior column and posterior hemitransverse||300||130||Good||28||3||16||NR|
|15/F/42||Anterior column and posterior hemitransverse||350||100||Anatomic||27||4||16||NR|
|20/F/25||Transverse||500||100||Anatomic||32||4||16||Obturator nerve injury|
|22/M/64||Anterior column and posterior hemitransverse||250||85||Anatomic||25||3||17||NR|