There have been long-standing controversies in classifying the pelvic ring fractures as stable and unstable patterns. Olson has described stable injury as one that withstands the physiological forces incurred with protected weight bearing or bed to chair mobilization without abnormal deformation of the pelvis, until bony or soft tissue healing occurs . The unstable pelvic fractures are fraught with a number of complications and demand timely interventions including adequate resuscitation and appropriate, stable fixation to ameliorate the morbidity and mortality associated with these injuries .
The patients included in our study had the antero-posterior compression type of injury, most common of which are the APC type II disruptions. These injuries predominantly involve the young male population and typically follow high energy road traffic accidents. As already emphasised, the earliest interventions that can save lives in these situations are resuscitation and control and management of hemorrhage . The importance of the radiological investigations especially computerised axial tomography in the surgical planning cannot be understated, although resuscitation and patient stabilisation must take precedence over these diagnostic procedures.
Although the surgical management of the antero-posterior compression injuries has not been straight-forward[9–12] and fraught with a number of controversies, there is a general consensus on the need for adequate surgical fixation and stabilisation when the symphyseal gap exceeds 2.5 cm. Early non-invasive stabilisation using a pelvic binder or pelvic sling to provide circumferential compression, or emergent, mini-invasive, compression techniques using the external fixators or C-Clamp (Ganz et al) may be necessary to arrest life threatening bleeding. Symphysis contact by these external appliances may be achieved by delivering forces as high as 177 ± 44 N and 180 ± 50 N for reduction of the partially stable and unstable pelves, respectively. The ideal management is, however, provided by stable, internal fixation only . There again, the controversy arises on the adequacy of single symphyseal plating, the need for double (perpendicularly placed) symphyseal plates, the ideal placement site of the plates (superior or anterior symphyseal surfaces), the types of plates used (reconstruction or low contact dynamic compression plates), the situations that need additional posterior pelvic stabilization, and so on. Although approach to the pubic symphysis using Pfannensteil incision is well-established and universally employed, a few authors have suggested the feasibility of minimally invasive techniques with indirect reduction and percutaneous fixation using multiple screws [13–15].
Classification systems have been considered the key-stone in deciding the management protocols in pelvic fractures . Although, the need for an additional posterior ring stabilisation (apart from symphyseal plating) to negate the vertical instability at sacro-iliac joint in type III APC injuries has been well acclaimed, a similar fixation in type II injuries has been an issue of debate over the past few decades. The anterior sacro-iliac ligament gets violated in all cases where the pubic symphysis is displaced more than 2.5 cm. Kapandji  has proposed that a small amount of nutation (nodding) movements occurs at the sacro-iliac joints with physiological weight bearing in these conditions (APC II). These movements tend to get transmitted anteriorly to the pubic symphysis. Multiple forms of symphyseal plate fixations like 4-hole dynamic compression plates, special angled plates, long plates and double-plate fixation have all been tried in type II APC injuries [17–19]. Single, anteriorly placed symphyseal plate provides a greater resistance to external rotation forces than superiorly placed plates in these antero-posterior compression injuries and is biomechanically, a more rigid fixation .
Lange et al  had used the anterior 2-hole plate fixation in symphyseal diastasis. The symphyseal double plate fixation (combination of anterior and superior symphyseal plates) provides the most rigid fixation of all; however, the procedure requires considerable dissection, expertise and time and may be associated with significant blood loss. The anterior 2-hole plate is a much less rigid fixation and helps in accommodating the physiological motion at the symphysis, yet adequately resisting the tensile stresses across the symphysis without loss of reduction. The soft tissue collar and tether provided by the inguinal ligament are not disrupted by the minimal dissection required for two-hole plate fixation.
Simonian et al [21, 22] had concluded that combined anterior and posterior fixation was optimal for APC type II injuries. Dujardin et al  also reported a decrease in the micromotions at the SI joint in these injuries when combining anterior plate fixation with sacroiliac fixation compared with isolated anterior plate fixation. MacAvoy et al  on the other hand suggested that single anterior plating of the pubic symphysis had similar biomechanical properties to two plates in pelvis with isolated rotational instability. They reported no difference between single and double plate fixation of the symphysis. Tile et al  had also concluded single anterior symphyseal plating as the ideal and sufficient fixation for APC injuries with a displacement of the posterior ring of less than 1 cm (rotationally unstable but vertically stable pelvic ring).
We have evaluated the clinical and radiological outcomes in our patients to assess the influence of multiple variables on the long term results. The presence of posterior ring injuries (APC III vs. APC II) is known to have a significant negative impact on the long term outcome although in our series the results were comparable when the posterior ring disruptions were adequately stabilized simultaneously. Almost half of the patients with APC type III injuries in our series presented with significant blood loss and hypotension. The urethral injury, although seen in only one of our patients, commonly accompanies such injuries and occurs as a result of shear forces at the junction of the prostatic and membranous urethra. Bladder/urethral injuries are also known rare surgical complications that occur during operative fixation of the symphyseal diastasis following inadvertent invasion of the viscus by inexperienced surgeons. There was a single case of post-injury urethral rupture (5.2%) in our series. The management of these genito-urinary injuries has been controversial with one school of surgeons supporting a supra-pubic cystostomy followed by a secondary repair of the urethral stricture and another school supporting supra-pubic cystostomy and primary urethral repair at the same sitting. We had performed an immediate supra-pubic cystostomy followed by the secondary urethral repair by an expert urologist.
One of the patients in our series developed urinary bladder herniation postoperatively. This complication, most probably results from an inadequate reduction of the diastasis or improper repair of the rectus sheath. We believe that in cases with marked disruption of the symphysis, avulsion of one head of the rectus abdominis is a common finding and there is no need to detach the rectus abdominis from the other side. Further, transverse sectioning of the rectus abdominis should be avoided as this impairs subsequent repair and healing of the abdominal wall. A careful surgical dissection and a meticulous repair go a long way in preventing soft tissue problems like bladder herniation in long run.
Although we used double symphyseal plating in one of our patients with Type III injury, we found single symphyseal plate along with posterior fixation to be adequate in stabilising such fractures. Some authors have recommended double symphyseal plating to be more stable fixation modality in these injuries with biplanar instability [20, 26, 27]. However, from our experience, we believe that a single plate provides an equally stable construct when combined with posterior ring fixation. Some authors have also suggested double symphyseal plating as the lone stabilisation procedure in APC III. On the contrary we believe that, if the posterior ring disruption is neglected, such a construct leads to a more compromised stability biomechanically.
Although our sample size was small for appropriate statistical tests to be done, we believe that the addition of the superior symphyseal plate does not add to the stability offered by a single anterior plate (contrary to the claim in the literature that the double plating technique offers greater rigidity). We reported 3 cases of implant failure in our series. This could have been partly due to inadequate reduction of the diastasis and party due to improper repair of the rectus insetion. We also believe intactness of the rectus abdominis insertion significantly adds to the stability of the constructs and this should be ensured whenever possible.
Our study had a few potential limitations. We had not used any patient validated scores (SF 12 or SF 36) or the assessment of the Activities of Daily Living (ADL) to evaluate the outcome. Nevertheless we believe that the clinical and radiological scores used by us for follow up assessment give us a fair idea about the functional outcome in our patients. The smaller sample size in our study also prohibited application of tests of significance. Nevertheless we share our experience in management of these devastating injuries.
To conclude, we believe that there is no gross dissimilarity in the outcomes between isolated anterior and combined symphyseal (perpendicular) plating techniques in APC II injuries. Single anterior symphyseal plating along with posterior pelvic ring stabilisation provides a stable fixation in type III APC injuries. We also believe that the amount of reduction achieved (gap less than 1 cm) is an important, independent variable in determing the long term outcome. Limited dissection and preservation of intactness of rectus sheath go a long way in avoiding post-operative complications and ensuring a satisfactory long term outcome.