Crescent Technique with Dual C-Shaped Reconstruction Plates for Posterior Acetabular Wall Fractures: An Invited Commentary

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Crescent Technique with Dual C-Shaped Reconstruction Plates for Posterior Acetabular Wall Fractures

In the article of “Crescent Technique Dual C-shaped Reconstruction Plates for Posterior Acetabular Wall Fractures,” the authors aimed to introduce a novel fixation method for posterior wall fracture and evaluate its feasibility [1]. They retrospectively analyzed 37 posterior wall fracture patients who underwent the crescent technique using dual c-shaped plates (overlapping distal ends), and concluded that this crescent technique was an effective and reliable fixation method for posterior wall acetabular fracture. It was a well-written and interesting paper which was enlightening. However, we would like to make some comments on the treatment of posterior wall fracture based on this study.

It was reported that posterior wall fracture was the most common type of acetabular fractures [2–4]. First of all, we should fully understand its injury mechanism. Most posterior wall fractures were caused by posterosuperior impaction from femoral head; thus, hip dislocation was always accompanied [5]. Emergency hip reduction and continuous preoperative traction of ipsilateral lower extremity were essential to lower the difficulty of fracture reduction. Posterior wall fractures could be subdivided into three subtypes according to Letournel–Judet classification system (single fragment, multiple fragments, and marginal impaction) [6]. Displaced fragments could be clearly revealed in the obturator oblique view and computed tomography (CT) scans [6].

As an unstable intra-articular fracture, open reduction and internal fixation were recommended for most posterior wall fractures. Serious complications including secondary hip dislocation may occur for the patients received unsuitable treatment. The majority of posterior wall detachment could be exposed through Kocher–Langenbeck (KL) approach without trochanteric osteotomy [6]. Thus, we applauded for the not application of trochanteric osteotomy during the surgical procedures in the study. The sciatic nerve should be located first and protected throughout the surgical procedures. Early exploration of sciatic nerve should be conducted if neurologic defect was accompanied. The integrity of capsule should be evaluated during the surgical process and timely capsulorrhaphy was essential if it was seriously torn. Capsular attachments provided the blood supply of displaced fragment; thus, dissection joint capsule from the posterior wall fracture was not recommended to avoid the formation free-and-devitalized wall fragment. What’s more, the capsular attachments may be conducive to the reduction and temporary fixation for the displaced fragments. It was required to remove intraarticular hematomas and free fragments within the articular cavity, which could be identified preoperatively on the CT scans. To avoid traumatic arthritis or femoral head necrosis, anatomical reduction of impacted articular surface was indispensable, usually using the femoral head as a template [6]. A void underneath from the impacted cancellous bone was formed after taking a small osteotomy several millimeters above the impacted fragment. Then, autogenous or freeze-dried cancellous allograft and subchondral mini-screws or bioabsorbable pegs fixation were recommended. Drainage should be routinely performed after the fixation in KL approach. Regular indomethacin treatment was a common method to prevent heterotrophic ossification, which may lead to poor clinical results. Although relevant techniques described were not presented in this manuscript, they were extremely important for the surgical treatment of posterior wall fractures.

Several fixation device had been applied to stabilize the fragments in the past decades; however, the choice of internal fixation was still controversial [4, 7]. It was reported that acceptable clinical results could be obtained through screw fixation alone for the patients with single posterior wall fragment [4]. However, plate fixation was essential for committed fractures or with severe osteoporosis because screws fixation alone could not provide adequate stability for the displaced fragments. Spring plate was recommended for patients with thin, small posterior wall fragments [7, 8]. The authors reported that dual C-shaped overlapped reconstruction plates were successfully inserted to accomplish the fixation of posterior wall fragments [1]. The buttress effect may be increased through crescent technique using two overlapping C-shaped plates. However, related biomechanical research should be performed to testify the hypothesis. The crescent technique may even applied to manage the detachment of posterior column because it could better encircle the acetabulum. While, the placement of overlapping plates was complex and technique demanding, repeated contouring of reconstruction plates was required to conform the anatomy of posterior wall, which would lower the strength of plate and was time consuming. Intraoperative adjustment of fixation device was difficult because the area of second plate was determined once the first one was inserted. Screw penetration into hip joint may occur for the crescent technique because of indirect visualization of articular surface of the acetabulum. How to lower the rate of penetration should not be neglected in the study. The advantages of the technique presented in this study over two reconstruction plates without overlapping should be emphasized in the manuscript. The subtypes of the posterior wall fractures were not involved and all cases recruited into this study totally received crescent technique fixation, which may be an inaccurate choice of fixation. For the patients with a simple fragment, the crescent technique may be unnecessary because single plate with screws insertion could provide adequate stability of acetabulum. After reading the paper, we thought the crescent technique especially suitable for the fixation of comminuted posterior wall fractures, which should be clearly elaborated in the manuscript. As far as I know, a kind of W-shaped acetabular angular plate (WAAP) especially designed for comminution of the posterior wall had been applied in the clinical practice [9]. The WAAP with different sizes conformed the specific anatomy of acetabulum; then, intraoperative pre-contouring procedures could be avoided. The majority area of posterior wall could be stabilized through single WAAP because there were two rows of holes for screw inserting. Thus, the placement and intraoperative adjustment of WAAP were much easier than those of crescent technique. Biomechanical tests showed that it could provide adequate stability for posterior/wall fractures [10]. What’s more, the drilling angles were specially designed away from the hip joint in the dangerous area. Thus, the incidence of screw penetration and intraoperative radiograph exposure may be lowered. Three dimensional printing digital technology had been applied in the diagnosis and preoperative surgical planning for posterior wall fractures. Individualized plate with screws could be made according to relevant information of displaced fractures with the assistance of three dimensional printing technology, which was a promising fixation technique.

Although there were some limitations in this study, it called our attention to the treatment of acetabular posterior wall fractures. Additionally, a novel fixation technique of displaced posterior wall fragments was proposed. In the future, more patients should be recruited to conduct prospective control studies involving multiple fixation techniques (lag screws, spring plate, crescent technique, WAAP) among different subtypes of posterior wall fractures respectively in order to determine the choice of individualized treatment according to the characteristics of displaced fragments.

Declaration of interest

The authors declare no conflict of interests regarding the publication of this article.