Pelvic deformity is responsible for complaints in many clinical areas—pain, gait abnormalities, genitourinary system, etc.—and is beyond the scope of this chapter. Occasionally, failure to heal or a nonunion will eventually displace, resulting in an associated malalignment (see Fig. 8.3). Additionally, initial displacement or deformity can separate the bone enough to cause a nonunion (Fig. 8.6).

Permanent nerve damage is a common cause of disability following pelvic injuries. A nerve injury occurs in 46% of the patients with an unstable vertical pelvis [5]. The most commonly affected nerve roots are L5 and S1, but any root from L2 to S4 may be damaged. In Huittinen’s [5] study of 40 nerve injuries, 21 (52.5%) were traction injuries, 15 (37.5%) were complete disruptions, and 4 (10%) were compression injuries. Interestingly, the lumbosacral trunk and superior gluteal nerve sustained traction injuries, while most of the disruptions occurred in the roots of the cauda equina. Compression injuries occurred in the upper three sacral nerve foramina in patients with fractures of the sacrum. Furthermore, the traction and nerve disruption injuries occurred in the vertically unstable pelvic injuries, while the compressive nerve injuries occurred following lateral compression of the pelvis. Lateral compression injuries of the pelvis often impact portions of the sacral bone into the foramen, resulting in compression of the nerve, and may require decompression if neurologic examination worsens.

A thorough neurologic examination is necessary to determine any preoperative deficits, and for intra-operative as well as postoperative nerve monitoring. Disruption of peripheral nerves should be evaluated by nerve conduction/electromyography tests. Peripheral disruptions may be repaired with possible salvage of some function or more consistent return of protective sensation. Myelograms and magnetic resonance imaging (MRI) are used to rule out spinal nerve avulsions.

Our studies on malunions and nonunions show that 57% of the patients had a preoperative nerve injury and only 16% were resolving postoperatively [2, 3]. Only one patient in our studies would not have the nonunion/malunion surgery again, and this was due to a postoperative nerve complication. The patient underwent two operations on a 16-year-old nonunion that was extremely mobile. An L5 nerve root injury occurred from likely reducing a vertical malreduced hemipelvis almost 5 cm. The patient required reoperation for persistent nonunion. At the time of the second operation, the posterior fixation was changed. The complaints of deformity were completely resolved, but the patient still suffered from pain in the L5 nerve distribution, despite having a stable pelvis.

An important aspect of the preoperative assessment is to discover a patient’s understanding and expectations regarding their clinical problem. Significant discussion is necessary prior to making a decision for surgery. The patient must make the final decision based upon realistic goals and an understanding of the risk of complications. Specific symptoms of deformity, such as limb shortening, sitting imbalance, vaginal impingement, and cosmetic deformity, are expected to be reliably addressed by surgery. The patient must be cautioned, however, that while the majority of the deformity can be corrected, the actual anatomic result is usually less than perfect. In our series of pelvic malunions, only 76% of our reductions had less than 1 cm of residual deformity [2, 3].

Posterior pelvic pain in the absence of a demonstrable nonunion or instability is often difficult to explain and may not completely or reliably improve with the correction of the pelvic deformity. Ninety-five percent of patients with malunion of the pelvis report improvement of their pain; however, only 21% have complete relief of their posterior pain [2, 3]. Radiographic evidence of SI joint arthrosis is not a reliable indication of the cause of posterior pelvic pain. However, in patients with a pelvic nonunion, a significant reduction in pain is seen (see Figs. 8.1, 8.3, 8.4, and 8.5).

Radiographic assessment includes five standard pelvis X-ray views (AP, both 45° oblique views, 40° caudad, and 40° cephalad), a weight-bearing AP X-ray, computed tomography (CT) scan, and a three-dimensional CT. The CT scan can be used to make a three-dimensional pelvic model. This model helps the surgeon to understand the deformity and plan preoperatively. The displacement and rotation of all fragments need to be understood so that appropriate release and reduction of fragments can be obtained. An obturator oblique clearly shows the SI joint on the ipsilateral side, while a single-leg weight-bearing AP determines stability of the nonunions. Technetium bone scans may be helpful in identifying the activity of the nonunion (atrophic or hypertrophic) but are not routinely ordered. Together, these multiple plain films and CT scans are used to assess nonunions and deformities of the pelvis. The displacements are often complex and include rotational and translational displacements around a three ordinate axis.

Plain X-rays will often show the anterior rami nonunions (see Figs. 8.2, 8.3, 8.4 and 8.5). A CT scan with sagittal and coronal reconstructions are required to define the posterior pelvic nonunions (see Figs. 8.1 and 8.4). When viewing the CT, all of the slices need to be studied. Musculoskeletal radiologists sometimes call a nonunion because a particular slice may not have any apparent boney bridging, but following the individual pieces will often show some slices with boney bridging, eliminating the diagnosis of nonunion.

Evaluating the nonunion site radiographically can determine whether the nonunion is hypertrophic (needs stability), oligotrophic (may need stability and biology), or atrophic (needs biology). Atrophic nonunion s, especially in the pelvis, should alert the surgeon to the possibility of a hormonal, nutritional, or medical problem. Working with a bone endocrinologist is helpful in these difficult cases (see Figs. 8.4 and 8.5). Infection is always a concern in any nonunion, so C-reactive protein (CRP) , erythrocyte sedimentation rate (ESR) , and white blood count (WBC) are routinely ordered. In infected nonunions (see Figs. 8.1 and 8.4), these parameters are important to follow; the use of these labs on and off antibiotics can help determine when the infection is controlled enough to fix the nonunion.

The best treatment is prevention [1, 6–9]. But even after adequate treatment, nonunions can occur (see Figs. 8.1, 8.2, 8.3 and 8.4). The problem of malunions and nonunions appears most commonly after inadequate initial treatment of displaced fractures and unstable pelvic ring injuries (see Fig. 8.5) [10]. In the acetabulum, nonunions can occur in transverse fractures when these fractures are treated nonoperatively, with inadequate fixation (e.g., one-third tubular plates without lag screws instead of reconstruction plates and lag screws), or there are medical problems with the patient (e.g., malnutrition, vitamin D deficiency, rickets). In pelvic nonunions, the same possible causes exist, nonoperative or inadequate fixation and medical comorbidities. Because most of the weight is transferred through the posterior pelvis, anterior rami nonunions rarely exist and, if present, are rarely symptomatic. However, if not treated, rami nonunions in elderly patients can lead to additional pathological fractures (see Fig. 8.4). More commonly nonunions occur posteriorly and are due to unrecognized instability of the pelvis with vertical instability that is treated nonoperatively or with an external fixator. These nonunions progress to malunions. From the technical standpoint, late correction is very difficult; the anatomy is altered and less recognizable, and the potential complications are increased. Osteotomies can easily damage the structures that lie on the opposite side of the bone. Scarring around nerves prevents the fragments from moving freely without causing nerve palsy.

Indications for surgery include pain, pelvic ring instability, and clinical problems relating to the pelvic deformity (gait abnormalities, sitting problems, limb shortening, genitourinary symptoms, vaginal wall impingement, etc.). A thorough knowledge of pelvic anatomy is required to understand the three-dimensional deformity. Furthermore, extensive preoperative planning is needed to determine the proper order of exposures for release, reduction, and fixation. Because each patient is different, it behooves the surgeon to individualize the treatment.

Previous literature focused on simple nonunions. These patients often do not require extensive anterior and posterior ring releases and reduction, and respond to in situ fusion only (see Fig. 8.4). Pennal and Massiah showed that patients treated with surgery are significantly better than those treated conservatively [11]. In their study, 11 out of 18 surgery patients returned to preinjury occupation versus five out of 24 conservatively treated patients. In nonunion cases with significant displacement, in situ fusions are unrewarding and leave the patient with complaints related to deformity as well as significant pain (see Fig. 8.3).

Surgical technique in the presence of significant deformity can be complex and is beyond the scope of this chapter, but one must be familiar with correction of deformities along with the management of the nonunion. This chapter will focus on healing the bones that generally require only one stage versus the more complex three-stage reconstruction as described by Letournel [2, 3, 7].

A radiolucent table with image intensification is commonly used for the procedure. The Judet table is also useful for positioning the leg anywhere in space to help with the approaches and exposure. Somatosensory-evoked potentials and motor-evoked potentials have been used on some patients intra-operatively that require significant correction of vertical displacement and but are not routinely used.

Painful nonunions without deformity can be treated with stabilization, bone graft, or both. A technetium bone scan can indicate activity of the nonunion (atrophic [requires bone graft] or hypertrophic [requires stabilization]). In most cases, it is not necessary, and surgery involves both bone graft and stabilization.

The preparation of the bone is the same no matter where the nonunion occurs. Cultures are always taken regardless of how the nonunion looks. We have seen a number of culture-positive less virulent organisms that do not form pus but infect and prevent bones from healing. The two sides of the bone are exposed with as minimal stripping as possible. It is important to remember that the blood supply comes predominantly from the soft tissue. The surgeon burrs both sides of the bone until cortical bleeding is seen. The surgeon then either burrs or drills inside the nonunion site to penetrate any cortical cap and get bleeding from the cancellous bone. The surgeon then lays cancellous strips from bleeding to bleeding bone. This is covered with good bleeding muscle. The fixation is either intra-medullary (i.e., iliosacral screws) or plate fixation next to the cancellous graft not covering it.

Nonunions of rami fractures are rare. If they occur, they are often located in the medial aspect of the pubis bone or in the symphyseal region. Because more than 90% of weight bearing is posterior, many nonunions of the anterior pelvic ring are asymptomatic. Because these are so rare, they are often not part of the differential diagnosis, and some patients can be evaluated by several specialists (obstetrics and gynecology, general surgery, etc.) before an X-ray identifies a painful nonunion (see Fig. 8.2). Often, treatment of symptomatic superior rami nonunion will heal the inferior rami nonunion, especially if the nonunion is hypertrophic or the underlying medical comorbidity has been corrected (see Fig. 8.5). However, there are cases where plating both the superior and the inferior rami is required, especially in cases of atrophic nonunions (see Fig. 8.2).

A Foley catheter is always placed preoperatively. A Pfannenstiel incision is made 2 cm cephalad from the symphysis. The decussation of the fascia fibers of the rectus abdominis marks the division between the two heads of the rectus. The two heads are split, with extreme care being taken to avoid entering the bladder. The surgeon then inspects the bladder to detect any perforations. The Foley should be palpated to ensure that the urethra is intact. A malleable retractor or lap sponge is then used to hold the bladder away from the symphysis pubis. Two Hohmann retractors are used to retract the two heads of the rectus from the superior surface of the symphysis pubis. The superior surface of the superior rami is cleaned for the plate, but the anterior insertion of the rectus remains intact. A large Weber clamp or pelvic reduction clamp can be used anteriorly to hold the symphysis together or rami fracture together. Usually, a six-hole 3.5 mm curved reconstruction plate is then implanted. Clinical research supports the implantation of this device [12]. Rarely, when a patient has a very small symptomatic nonunion of the pubis or late painful instability of the symphysis, a symphyseal fusion is indicated. When a fusion of the symphysis is needed, an additional four-hole plate is used anterior to the symphysis with cancellous bone graft. Additionally, when fusion of the symphysis is indicated, an eight to ten-hole plate is used rather than a six-hole plate superiorly. Through the Pfannenstiel approach, the SI joints can be visualized and the quadrilateral surface exposed via the modified Stoppa approach [13]. Therefore, a plate can be placed from the symphysis to the SI joint along the brim superiorly bilaterally. Furthermore, a plate can be placed within the pelvis from the symphysis along the quadrilateral plate to the SI joint. Plates or screws can be used on the inferior rami (see Fig. 8.2) via a direct approach, with the patient in the lithotomy position. This position allows the surgeon to also perform a Pfannenstiel incision as well. Rarely, in already osteoporotic bone, rami nonunion can cause enough instability to cause insufficiency fractures posteriorly (see Fig. 8.4). Elderly simple rami fractures need to be worked up for osteoporosis to prevent this disastrous complication. The initial treatment of these insufficiency fractures includes touchdown weight bearing with no range of motion or exercises to that side for eight weeks. If the patient continues to be symptomatic, the pelvis is stabilized with posterior iliosacral screws (for posterior insufficiency fractures) and/or platting of rami fractures with another eight weeks of touchdown weight bearing. These patients are aggressively treated (parathyroid hormone, vitamin D, calcium, etc.) by a bone endocrinologist. Furthermore, the failure of rami to heal properly may cause further displacement and eventual pelvic malunion (see Fig. 8.3).