abank day 4-6

1. PREFERRED RESPONSE 4

2. Patients with multiple injuries including a pelvic ring fracture who present with hemodynamic instability should have a pelvic binder or circumferential pelvic sheet placed as part of their initial resuscitation.

A systematic approach to search for sources of bleeding and control ongoing hemorrhage is necessary for patients who present with hemodynamic changes in the setting of a pelvic ring fracture. Management of continued hypotension after pelvic binder placement is controversial and varies among trauma centers.

Krieg et al. prospectively evaluated 16 patients with unstable pelvic ring injuries initially managed with a novel circumferential compression device. The authors found substantial reduction in pelvic width with the use of this compressive device in patients with volume expanding pelvic ring fractures.

Croce et al. retrospectively compared patients with unstable pelvic ring injuries who were treated with either emergent pelvic fixation (EPF) or a pelvic orthotic device (POD). The authors found that those patients treated with POD had decreased transfusion requirements and shorter length of hospital stay.

Routt et al describe their technique for circumferential pelvic antishock sheeting (CPAS). The authors provide an illustrative case and discuss the potential advantages of sheet application versus other techniques of pelvic stabilization.

Incorrect Answers:Answer 1: External fixation of pelvic ring fractures can be used to assist with resuscitation but pelvic binder application should be attempted firstAnswer 2: The use of pelvic angiography is controversial and institution specific however some centers utilize pelvic angiography as part of the algorithm for management of ongoing hemorrhage.Answer 3: Pelvic packing is utilized in some centers to control ongoing pelvic hemorrhage however it is not used as initial management of patients with hemodynamic instabilityAnswer 5: Percutaneous iliosacral screws can also be utilized as a form of resuscitation however they should not be used as as first line of management


The clinical presentation is consistent for a mildly displaced parasymphyseal fracture in a pediatric patient with an open triradiate cartilage. Weight bearing as tolerated is the most appropriate treatment.

In skeletally immature pelvic ring fractures, the majority of cases can be treated nonoperatively. Open reduction and internal fixation is required for acetabular fractures with >2 mm of fracture displacement and for any intra-articular or triradiate cartilage fracture displacement >2 mm. External fixation is necessary for pelvic ring displacement of >2 cm to prevent limb-length discrepancies.

Holden et al. emphasize that children with open triradiate cartilage have different fracture patterns than do children whose triradiate cartilage has closed. They report because of the immaturity of the pelvis, the iliac wing is weaker than the elastic pelvic ligaments, resulting in bone failure before pelvic ring disruption has a chance to occur. For this reason fractures usually involve the pubic rami and iliac wings and rarely require surgical treatment.

Spiguel et al. reviewed 2850 pediatric trauma admissions at their institution and reviewed cases with a pelvic ring fracture. They found that although pelvic fractures are an uncommon injury in pediatric trauma patients, the morbidity associated with these injuries is significant. They report while the majority of pelvic fractures in children are treated nonoperatively, more than one-half of these patients have concomitant injuries requiring operative management.

Figure A shows an inferior rami fracture in a pediatric patient with an open triradiate cartilage.

Incorrect Answers:Answers 1,3,4,5: These treatment options are not appropriate in a stable pelvic ring fracture in a child with open triradiate cartilage.


The patient has an Anterior-Posterior Compression type 3 pelvic ring injury (APC3), and this injury places the patient at risk of life- threatening hemorrhage. The most appropriate next step in the trauma bay is to place the patient in a pelvic binder in order to minimize pelvic volume and impart stability to the injured hemipelvis to allow for clot formation.

Pelvic fractures are high energy injuries with a high association of concomitant musculoskeletal trauma and damage to multiple organ systems. It is important that any patient with a high-energy pelvic ring injury undergo a complete work-up including a CT of the chest abdomen and pelvis to look for alternative sources of bleeding. Application of a pelvic binder should occur once a pelvic ring injury is identified as part of the ongoing resuscitation of the patient.

Karadimas et al. retrospectively reviewed 34 patients at a single center who underwent pelvic arterial embolization as part of their resuscitation. APC injuries had the highest mean transfusion rate during the initial 24 hours, and the overall mortality for pelvic fractures requiring embolization was 23.5% in this series.

Manson et al. conducted a retrospective case-controlled study, evaluating mortality factors on LC-1 fractures. They found that in LC-1 fractures, the sacral fracture pattern does not predict mortality; however, mortality rate was increased in patients with a brain injury, chest injury, or abdominal injury.

Figure A demonstrates an APC3 pelvic ring injury with widening of both the symphysis and the right SI joint. Illustration A demonstrates the same injury as seen in Figure A after application of a pelvic binder with improved alignment of the pelvic ring. Illustration B shows appropriate application of a pelvic binder in a multiply injured patient.

Incorrect Answers:Answer 1: While this patient may need to go emergently to the OR for multiple reasons, the work-up needs to be completed. However, the patients pelvis should be stabilized with a pelvic binder in the interim.Answer 2: These images should be obtained, but the pelvis should be closed with a pelvic binder first.Answer 3: While the pelvis may not be the only location of bleeding, the patient has a known source for bleeding, and it can be quickly stabilized with a pelvic binder. After the pelvic binder is placed, continued resuscitation and investigation of other possible locations of bleeding should occur.Answer 4: While this patient may benefit from embolization, the first step is to close down the pelvis. Closing down the pelvis may prevent the need for embolization.


Alternating single-leg-stance radiographs are used for the diagnosis of chronic or subtle pelvic instability.

Pelvic instability is a rare etiology of lumbar and low-back discomfort; patients report subjective instability and mechanical symptoms. Static radiographs (AP pelvis, inlet pelvis, outlet pelvis) are often not adequate for diagnosis of this condition.

Garras et al. performed a study of healthy volunteers and reported on the normal range of physiologic motion with single leg stance radiographs. They found that multiparous women exhibited the most symphyseal motion with alternating single leg stance weightbearing AP pelvic radiographs, and up to 5mm of symphyseal translation was seen in healthy, asymptomatic patients.

Siegel et al. reviewed 38 patients with pelvic instability and pain. They found that single leg stance radiographs were more indicative of instability than standard AP pelvis and inlet/outlet radiographs. They found that up to 5 cm of sympyhseal translation can be present with these injuries.

Illustration A shows a single leg stance (left leg) AP pelvis radiograph with cephalad displacement of the left hemipelvis. Illustration B shows a single leg stance (right leg) AP pelvis radiograph, with cephalad displacement of the right hemipelvis.

Incorrect Answers:Answer 1,3,4,5: Standing alternating single-leg-stance radiographs are not used for diagnosis or evaluation of these disorders.


The lateral sacral view is used to place percutaneous iliosacral screws. Sacral alar morphology has been shown to be variable from patient to patient. Therefore, intraoperative fluoroscopy is recommended. During placement of the screws, the L5 nerve root is at risk.

Routt et al (1997) examined the sacral slope and sacral alar anatomy in cadavers and a series of patients. They determined that the pelvic outlet and lateral sacral plain films provide the best plain radiographic view of the sacral ala. They recommended routine usage of these views intraoperatively to guide screw placement.

Routt et al (2000) reported on the early complications of percutaneous placement of iliosacral screws for treatment of posterior pelvic ring disruptions. While technically challenging, this technique leads to less blood loss and lower rates of infection compared to traditional open techniques.

Barei et al described methods of anterior and posterior pelvic ring disruptions. They determined that successful placement depends on accurate closed reduction, excellent intraoperative fluoroscopic imaging, and detailed preoperative planning. Early treatment decreased hemorrhage, provides patient comfort, and allows early mobilization.


Figure A shows an unstable bilateral pelvic ring injury. Percutaneous posterior iliosacral screw fixation places the L5 nerve root at risk as it courses across the sacral ala. Injury to the L5 nerve root would typically result in weakness in great toe extension and sensory changes on the dorsum of the foot. It is important to notice that L5 often partially innervates tibialis anterior along with L4, so weakness to ankle dorsiflexion may be present as well. Illustration A shows the post-operative films with bilateral iliosacral screws.

Routt et al examined the sacral slope and sacral alar anatomy in cadavers and a series of consecutive patients. They determined that the pelvic outlet and lateral sacral plain films provide the best plain radiographic views of the sacral ala. They recommended routine usage of these views intraoperatively to guide screw placement.

In another study, Routt et al reported on the early complications of percutaneous placement of iliosacral screws for treatment of posterior pelvic ring disruptions. While technically challenging, this technique leads to less blood loss and lower rates of infection compared to traditional open techniques.

Illustration B displays the root diagrams for sensation, reflex, and motor of the L4-S1 nerves.

Incorrect answers:1: Weakness to knee extension would be caused primarily by an injury to the L4 nerve root.2: Decreased patellar reflex would be caused primarily by an injury to the L4 nerve root.4: Weakness in ankle plantar flexion would be caused primarily by an injury to the S1 nerve root.5: Decreased Achilles reflex would be caused primarily by an injury to the S1 nerve root.

Illustrations:AB


The outlet view best guides superior-inferior screw orientation during percutaneous S1 screw placement. This is due to the relative forward flexion of the sacrum and pelvis due to pelvic incidence. A lateral sacral view and an inlet pelvis view would best guide anterior-posterior screw orientation.

Routt et al did a review of percutaneous techniques of pelvic surgery. Although anterior pelvic external fixation remains the most common form of percutaneous pelvic fixation, iliosacral screws have the advantage of stabilizing pelvic disruptions directly while diminishing operative blood loss and operative time. They stress importance of a thorough knowledge of pelvic osseous anatomy, injury patterns, deformities, and their fluoroscopic correlations for surgical success.

Routt et al also looked at the complications that can result from percutaneous iliosacral screw placement. Complications ranged from inability for adequate imaging due to patient obesity, L5 nerve root injuries, fixation failure, and sacral nonunions. They support quality triplanar fluoroscopic imaging during iliosacral screw insertions to help accurately reduce injured posterior pelvic rings.

Illustration A is an example of an outlet view image status post anterior pelvic ring plating and percutaneous iliosacral screw. This outlet view allows superior S1 neural foramen visualization to help guide screw placement and avoid nerve injury.


APC II injuries are unstable injuries and occur as a result of high-energy trauma. Anatomic structures which are injured or torn include the pubic symphysis, anterior iliosacral ligaments, and the sacrotuberous ligaments. The posterior sacroiliac ligaments are spared in APC-II injuries, and differentiate an APC-II injury from an APC-III injury, in which the posterior ligaments are also torn.

Burgess et al review the classifications of pelvic ring disruptions and their association with mortality. They concluded that APC injuries required more blood replacement and were related to death more often than lateral compression, vertical shear, or combined mechanism pelvic injuries.

Tile studied the anatomy of anterior to posterior pelvic ring injuries. Although the anterior structures, the symphysis pubis and the pubic rami, contribute to 40% to the stiffness of the pelvis, clinical and biomechanical studies have shown that the posterior sacroiliac complex is more important to pelvic-ring stability. The posterior sacroiliac ligamentous complex is more important to pelvic-ring stability than the anterior structures and therefore, the classification of pelvic fractures is based on the stability of the posterior lesion.


Lateral compression type II fractures (as described by the Young-Burgess Classification System) are associated with a crescent fracture of the iliac wing located on the side of impact. A representative CT scan image and illustration of this injury are shown in Illustrations A and B respectively. A table describing each pelvic injury and their associated complications is shown in Illustration C. Illustration D shows each Young-Burgess pelvic injury type.

Burgess et al discuss the effectiveness of a treatment protocol as determined by their pelvic injury classification and hemodynamic status. The injury classification system was based on lateral compression, anteroposterior compression, vertical shear, and combined mechanical injury types. They found that their classification-based treatment protocols reduce the morbidity and mortality related to pelvic ring disruption.

Tile discusses acute pelvic trauma and his classification system for pelvic injuries (ie. Types A, B, and C). He states that any classification system must be seen only as a general guide to treatment, and that the management of each patient requires careful, individualized decision making.

Incorrect Answers:Answer 2: This describes an APC-II injuryAnswer 3: This describes an APC-III injuryAnswer 4: This describes and LC-I injuryAnswer 5: This describes an LC-III injury (ie. "wind-swept pelvis")11. PREFERRED RESPONSE 2

In the management of patients with multiple injuries, controversy often arises as to the appropriate method of initial pelvic stabilization. It is generally agreed upon that applying an external frame is appropriate in the setting of an unstable patient with intraperitoneal fluid and labile blood pressure. Ex-fix placement can support hemodynamic stabilization and assist the general surgeons with their laparotomy procedure. Plate or screw fixation of the pelvis should be delayed because the laparotomy takes precedence in a patient who is hemodynamically unstable, and internal fixation in the presence of bowel contamination can result in increased rates of infection.

Furthermore, Tile noted increased septic complications with intrapelvic hardware fixation in the setting of intraperitoneal soft tissue damage and bleeding. Angiography and embolization may help with the pelvic bleeding, but will not stabilize the pelvis during the laparotomy. The review article by Tile et al discusses the assessment of the patient with a pelvic injury, and summarizes the various methods of temporary and definitive pelvic fixation.


Of the pelvic ring injuries, APC type III have the highest rate of mortality, blood loss, and need for transfusion. They also have a high rate of urogenital injury and abdominal organ injury. Lateral compression injuries (especially type III) have the highest rate of head injury. Vertical shear and combined injuries also have significant rates of concomitant injuries. The referenced article by Dalal et al is a review of Shock Trauma's pelvic ring injuries; they found significant increases in associated injuries as the grade of pelvic ring injury increased, regardless of mechanism/pattern. The aforementioned information was also found to be true with their patient review.


Unstable anteroposterior compression (APC) pelvic fractures are most appropriately managed with a pelvic binder or circumferential pelvic sheeting as described by Routt et al in the emergency room prior to definitive treatment. Illustration A demonstrates the utility of circumferential wrapping for the case shown in Figure A. Rapid, temporary fixation of unstable pelvic fracture patients with hemodynamic instability can be performed in the trauma bay. Pelvic binders can remain in place during further diagnostic tests such as pelvic vessel angiography.

Bottlang et al performed a cadaveric study in JBJS of Young-Burgess type-II and III anteroposterior compression fractures and found that a pelvic binder reduced rotation instability by 61%.

The study by Krieg et al followed 16 patients treated with pelvic binders and found that the binder reduced the pelvic fracture displacement by 9% which closely approximated the reduction achieved with definitive fixation.

The Bottlang article published in JOT is a cadaveric study which determined that 180 +/- 50 Newtons of circumferential compression is needed to stabilize an unstable pubis symphysis diastasis. Tile Type A pelvic fractures are stable and include avulsion, iliac-wing, anterior-arch fracture due to a direct blow, or transverse sacrococcygeal fractures.


High energy pelvic injuries such as the one seen in Figure A continues to be a source of high mortality in orthopaedics. Active involvment of the orthpaedic surgeon in managing these life threatening injuries remains critical. A sheet or pelvic binder needs to be emergently applied in this clinical scenario. An aggressive resuscitation protocol must also be initiated. The review article by Hak et al discussed the advances in prehospital, interventional, surgical, and critical care that have led to increase survival rates for pelvic injuries. Gonzalez et al found that initial coagulopathy in trauma patients was associated with decreased survival. They noted that hypothermia and acidosis was well managed but pre-ICU coagulopathy was the most difficult to treat. They recommended early FFP in a FFP:PRBC ratio of 1:1


According to the referenced article by Griffin et al, the risk of postoperative loss of reduction is greatest with a vertical sacral fracture pattern (13%, all within 3 weeks). There was no significant association between failure and anterior fixation method, iliosacral screw arrangement or length, or any demographic or injury variable.

Their conclusion: "Percutaneous iliosacral screw fixation is a useful technique in the management of vertically unstable pelvic fractures, but a vertical sacral fracture should make the surgeon more wary of fixation failure and loss of reduction."


Pelvic external fixation with supraacetabular pins through the AIIS can be utilized to stabilize a pelvic fracture. While using this technique, care must be taken not to injure the lateral femoral cutaneous nerve (LFCN). Gardner et al describe the technique for placement of supraacetabular external fixation pins and state that pins in this location are more stable biomechanically compared to other locations in the iliac crest. Grothaus et al performed a cadaveric study to determine the anatomic detail and variation of the LFCN and the distances it traveled from various landmarks.The found the nerve to potentially be at risk as far as 7.3 cm medial to the anterior superior iliac spine along the inguinal ligament and as much as 11.3 cm distal on the sartorius muscle from the anterior superior iliac spine. Riina et al performed a cadaveric study to define the neurovascular structures at risk with the placement of anterior-posterior locking screws in the proximal femur. They found that risks to the neurovascular structures during anterior-posterior locking in the proximal femur are diminished if locking is performed above the level of the lesser trochanter.


Figure A, a coronal CT image, shows a vertical sacral fracture, which creates a vertically unstable pelvic ring. Percutaneous iliosacral screw fixation is a useful technique in the management of vertically unstable pelvic fractures, but a vertical sacral fracture should make the surgeon more wary of fixation failure and loss of reduction.

According to the referenced study by Griffin et al, fixation failure of iliosacral screws was significantly associated with vertical sacral fractures and not with any of the other answers listed above. All cases of hardware failure occured within the first 3 weeks; a lesser relationship between hardware failure and sacroiliac joint injury was noted.


Figure A shows an APC III injury, which is a rotationally and vertically unstable injury, with damage to the anterior ring, pelvic floor, and posterior ligamentous stabilizing structures.

The referenced study by Sagi et al found that biomechanically, a percutaneous iliosacral screw and anterior ring internal fixation was the most stable construct. In addition, he found no biomechanical support for addition of a second iliosacral screw.


Unstable pelvic fractures can be devastating injuries often resulting in significant morbidity and even death.

According to the referenced study by Smith et al, fracture pattern and angiography/embolization were not predictive of mortality in patients with unstable pelvic injuries. The three factors they found to be predictive were: increased blood transfusions in the first 24 hours, age >60 years, and increased ISS or RTS scores. Deaths were most commonly from exsanguination (24 hours).

Incorrect Answers: Choices 1-4 do not correlate with increased blood transfusions to the extent of Option 5.


Unstable anterior and posterior pelvic ring injuries are amenable to percutaneous treatment if reduction is able to be obtained in a closed manner and appropriate radiographic visualization is able to be achieved. In the 1996 reference by Routt et al, proper SI screw placement is described. Pelvic inlet, outlet, and lateral sacral images must be obtained to safely place a percutaneous iliosacral screw. The iliac cortical density seen adjacent to the SI joint is the anterior edge of the insertion safe zone, and is only able to be seen on the lateral image. Failure to place the screw behind this radiographic line would lead to an "in-out-in" screw (in the ilium, and then exiting anterior to the sacral ala, only to re-enter in the sacral body), which would cause direct injury to the L5 nerve root.

In the 2000 reference by Routt et al, they state "a thorough knowledge of pelvic osseous anatomy, injury patterns, deformities, and their fluoroscopic correlations are mandatory for percutaneous pelvic fixation to be effective."

Illustration A shows a representative lateral sacral radiograph, with the major anatomic landmarks labeled. Safe SI screw insertion in the S1 body should be underneath the sacral ala line to minimize risk of a "in-out-in" screw that would come out in the area of the ala and injure the L5 nerve root that sits directly on top of this structure. Dysmorphic pelvic rings will often have a more vertical sacral line, or one that starts more inferiorly.

21. 22. PREFERRED RESPONSE 2

The figure shows an anteroposterior pelvic ring injury. The most common urological injury with pelvic ring injuries remains the posterior urethral tear, followed by bladder rupture.

Watnik et al notes lower urinary tract (bladder to end of urethra) injuries in up to 25% of patients with this injury. He reports that when contaminated urine communicates with the anterior arch, the possibility of infection exists, and early repair of bladder disruptions with simultaneous anterior arch plating minimizes this risk.

Routt et al notes that even with simultaneous treatment of these injuries, complications are common (late stricture in 44%, impotence in 16%, delayed incontinence in 20% of females, anterior deep pelvic infection in 4%). Despite this, they report that early urological repairs are easily performed at the time of anterior pelvic open reduction and internal fixation.


Pelvic ring injuries are associated with a high incidence of mortality mainly due to retroperitoneal hemorrhage. Early stabilization is an integral part of hemorrhage control. Temporary stabilization can be provided by a pelvic sheet, sling, or an inflatable garment. However, these devices lack control of the applied circumferential compression.

Krieg et al showed a pelvic circumferential compression device (PCCD) significantly reduced the pelvic width by 9.9 +/- 6.0% of external rotation (APC) pelvic injuries, and did not overcompress internal rotation (LC) injuries.

Bottlang et al determined that a widened pelvis can be effectively reduced in the emergency department with a pelvic strap (binder). While the other choices are urgent as well, hypotension caused by pelvic widening demands the most immediate attention.


The posterior sacroiliac ligaments are not disrupted in an APC type II pelvic fracture.

Young and Burgess classification of pelvic ring injuries is largely based on the mechanism and energy of injury. An APC type I involves slight widening of pubic symphysis and/or anterior sacroiliac (SI) joint. An APC II is a continuation of this force, and additionally involves a disrupted anterior SI joint, as well as sacrotuberous and sacrospinous ligaments. An APC III also involves disrupted posterior SI ligaments, causing complete SI joint disruption with potential translational and rotational displacement.

The reference by Young et al is a classic article that describes the Young and Burgess classification of pelvic ring injuries. They retrospectively analyzed pelvic ring radiographs and discussed four patterns of injury: anteroposterior compression, lateral compression, vertical shear, and a complex/combined pattern.

The reference by Burgess et al is a validation of the aforementioned classification and study, as they reviewed 210 consecutive patients who sustained a pelvic ring injury. They validated the classification scheme and found that overall blood replacement averaged: lateral compression, 3.6 units; anteroposterior compression, 14.8 units; vertical shear, 9.2 units; combined mechanical, 8.5 units. Overall mortality was: lateral compression, 7.0%; anteroposterior, 20.0%, vertical shear, 0%; combined mechanical, 18.0%.

Illustration A shows an APC-II injury pattern - (a) is an outlet radiograph, (b) is an axial CT cut, (c) is a 3-D CT cut, and (d) is a representative fixation construct.

Incorrect answers:1,2,4,5: An APC - 2 pelvic ring injury involves injury to all of these structures.


The clinical presentation and radiograph is consistent with an open-book type parturition-induced pelvic dislocation.

The case series by Kharrazi et al reports four patients treated with open-book type parturition-induced pelvic dislocations. The authors advocate nonoperative treatment with bedrest and a properly positioned pelvic binder in the acute setting for patients with a symphyseal diastasis less than 4.0 cm. All four patients had significant symptoms and radiographic widening (anterior splaying) of the sacroiliac joints. The three patients who had presented acutely were treated with closed reduction and application of a pelvic binder, while two had closed reduction of their pelvic dislocation while anesthetized with a general anesthetic. At latest follow-up the diastasis at the pubic symphysis reduced to an average of 1.7 cm (range: 1.5-2.0) The authors advocate nonoperative treatment with bedrest and a properly positioned pelvic binder in the acute setting for patients with a symphyseal diastasis of 4.0 cm of less and operative treatment for diastasis greater than 4cm.


Care must be taken when placing a retractor on the anterior aspect of the sacrum, as the L4 and L5 nerve roots are both at risk.

Illustration A shows a diagram of the lumbosacral plexus, indicating the proximity of the L4 and L5 nerve roots to the anterior sacrum and SI joint.

The first referenced article by Atlihan et al reported on the anatomy of the anterior sacroiliac joint and reported that the L4 nerve root is within 1 cm of the joint at its inferior margin.

The second article by Ebraheim et al found that the L4 and L5 nerve roots are 10 mm medial to the sacroiliac joint at the pelvic brim.


An anterior approach to the sacroiliac (SI) joint is indicated with displaced SI joint dislocations that cannot be reduced with closed or percutaneous techniques. One contraindication to anterior exposure of the SI joint is comminuted sacral fracture patterns.

Posterior pelvic ring injuries that are unable to be reduced by closed techniques may require open reduction via anterior or posterior approaches. Relative contraindications to anterior approach include comminuted sacral fractures, morbid obesity, iliac wing external fixation, and ipsilateral diverting colostomy. In the presence of a comminuted sacral fracture, aggressive medial dissection would be required and would place the L5 nerve root at risk.

Simpson et al describe their initial results with open reduction and internal fixation of the SI joint via an anterior exposure in a series of 16 patients. They note that sacral alar comminution is a contraindication to the anterior approach

Jones provides an overview of the operative treatment of posterior pelvic ring injuries. He demonstrates reduction and fixation techniques via both anterior and posterior exposures.

Incorrect Answers:Answer 2: Prior laparotomy is not a contraindication to open anterior approach if the bowel is in continuity and there is no evidence of wound infectionAnswer 3: Supracetabular external fixation does not interfere with anterior approach to the SI jointAnswer 4: Anterior pelvic ring injuries such as parasymphyseal fractures do not affect the choice of approachAnswer 5: An ipsilateral proximal femur fracture does not affect the choice of approach


The injury shown in Video V reveals a right sided posterior ilium fracture, which is known as a crescent fracture. The presence of a crescent fracture is consistent with a lateral compression type 2 injury; this differentiates this from a type I injury. The ipsilateral anterior sacrum has a small impaction injury anteriorly while the contralateral SI joint has a minor amount of anterior sacral impaction indicative of a lateral compression type I injury.

The reference by Burgess et al is the primary source of the mechanism classification of pelvic ring injuries. Overall blood replacement averaged 5.9 units (lateral compression, 3.6 units; anteroposterior compression, 14.8 units; vertical shear, 9.2 units; combined mechanical, 8.5 units). Overall mortality was 8.6% (lateral compression, 7.0%; anteroposterior, 20.0%, vertical shear, 0%; combined mechanical, 18.0%).

Incorrect answers:1: The presence of a crescent fracture means this is at least a LC-2 injury. The left-sided fracture pattern is consistent with an LC-1 pattern.3: A vertical shear fracture pattern would exhibit some vertical displacement and does not typically exhibit the crescent fragment.4: The fracture pattern does not match an anterior-posterior compression pattern.5: The fracture pattern does not match an anterior-posterior compression pattern.


Penetration of an iliosacral screw through the sacral ala would injure the ipsilateral L5 nerve root (great toe dorsiflexion). This can be avoided with proper understanding of the sacral anatomy as well as iliosacral screw starting points. The three required views for placement of this screw are: lateral sacral, pelvic inlet, and pelvic outlet.

The referenced study by Ziran et al is an excellent review of fluoroscopic evaluation of screw placement. They reported that the anterior border of the S1 body is best seen with overlap of the S1 and S2 anterior cortex while the superior aspect of the S1 foramen is best seen with overlap of the S2 foramen on the superior pubic ramus.

The referenced study by Routt et al reviewed 177 patients with pelvic ring injuries treated with these screws and found that quality triplanar imaging decreased intraoperative and postoperative complications. They also recommend supplemental fixation of iliosacral screws with posterior plating in noncompliant patients.


This question is a simple review of anatomy and nerve innervation. The L5 root is at risk with an "in-out-in" screw, as described in the question, as the nerve root is just anterior to the sacral ala as it enters the true pelvis. L5 is primarily evaluated by extensor hallucis longus function. L4 is tested with tibialis anterior function and S1 by gastroc-soleus function (ankle plantarflexion).


Figure A shows an intraoperative outlet view, which provides the best visualization of the neural foramina (and possible screw placement into these foramina). This view provides information regarding cephalad-caudad placement of the screw, whereas the inlet view provides information regarding the anterior-posterior position of the screw. The lateral sacral view provides information regarding the sagittal curvature of the sacral ala and gives information regarding possible iatrogenic L5 nerve injury as it goes over the sacral ala.

The referenced article by Routt et al is a review article regarding the safety and techniques of percutaneous pelvic ring fixation.

32. PREFERRED RESPONSE 5The clinical scenario is consistent with a high-energy sacral fracture. The radiographs in figures A and B demonstrate a sacral fracture with posterior displacement of the right hemipelvis seen on the inlet view. Figures C and D are axial and sagittal CT images which show a displaced fracture of the right hemisacrum along with a transvere fracture component through the S3 body . Diminished perianal sensation is concerning for an S2 nerve root injury.

Mehta et al reviewed the current management of sacral fractures. They note that the S1 and S2 nerve roots are more likely to be injured with sacral fractures as they occupy 1/3 to 1/4 of the neural foramina, as opposed to S3 and S4, which only occupy 1/6 of the neural foramina.

Robles reviewed the current literature to ascertain principles of evaluation and treatment for transverse sacral fractures. The author notes that injury to nerve roots S2 to S5 is manifested by impairment of urinary and anal continence and sexual function.

The first illustration demonstrates the sacral nerve root dermatomal distribution. The second shows a pelvic cadaver dissection demonstrating the sacral nerve roots as they exit the foramina.


Answering this question relies on knowledge of the Denis classification of sacral fractures and their associated risks of nerve injury. Figure A represents a Denis Zone 3 (medial to the foramina) sacral fracture, which has the highest associated risk of nerve injury.

Denis et al outlined a novel classification system of sacral fractures based on the position of the fracture line relative to the sacral foramina. The authors found a 56.7% incidence of nerve injury in fractures that extended medial to the sacral foramina (zone 3), compared with 28.4% for fractures through the foramina (zone 2), and 5.9% for fractures lateral to the foramina (zone 1).

Mehta et al reviewed the current principles for management of sacral fractures. They note that bowel, bladder and sexual dysfunction occur in 76% of patients with zone 3 sacral fractures.

Illustration A below demonstrates the Denis classification of sacral fractures.

Incorrect Answers:2. Figure B shows a zone 1 sacral fracture, which has a 5.9% incidence of nerve injury3. Figure C shows a zone 2 sacral fracture, which has a 28.4% incidence of nerve injury4. Figure D shows a sacroiliac joint dislocation, not a sacral fracture5. Figure E shows a zone 1 sacral fracture with an associated iliac fracture (crescent fracture)


Combined iliosacral and lumbopelvic fixation (triangular osteosynthesis) for sacral fractures has the greatest stiffness when used for an unstable sacral fracture.

The referenced article by Schildhauer et al is a cadaveric study that examined the biomechanical properties of different fixation constructs under cyclic loading and demonstrates that triangular osteosynthesis for unstable transforaminal sacral fractures provides significantly greater stability than iliosacral screw fixation under in-vitro cyclical loading.

Illustration below shows the radiographic appearance of lumbopelvic fixation. The addition of iliosacral fixation would complete triangular osteosynthesis.


The posterior wall is best visualized on the obturator oblique pelvic view.

The obturator oblique and iliac oblique views make up the Judet views that are used to evaluate acetabular fractures, along with a standard AP pelvis radiograph. The obturator oblique pelvic view is best to view the anterior column and posterior wall in detail. The iliac oblique shows the profile of involved iliac wing, the posterior column, and the anterior wall.

Letournel reviewed his classification and treatment protocols, based on his 22 years of experience at that time. He noted that perfect anatomical reduction of the acetabulum led to the best outcomes.

Patel et al reviewed of the Letournel classification, and they found moderate to high inter- and intra-observer reliability with this classification system. The presence of articular displacement, marginal impaction, incongruity, intra-articular fragments and osteochondral injuries to the femoral head were found to have less reliability (intra- and interobserver).

Illustration A shows a right-sided obturator oblique radiograph, while Illustration B shows a right-sided iliac oblique radiograph. Illustration C shows a diagram of the obturator oblique radiograph, with the radiographic lines marked out.

Incorrect Answers:

Answers 1: Inlet pelvic imaging is best for assessing pelvic ring injuries (rotation and anterior-posterior or medial-lateral translation).

Answers 2: Outlet pelvic imaging is best for assessing pelvic ring injuries (proximal-distal translation, rotation).

Answers 3: AP pelvis is a good screening tool for pelvic and acetabular fractures.

Answers 5: Iliac oblique pelvis is best for assessing the posterior column and anterior wall of the acetabulum.


Dynamic fluoroscopic examination of the affected hip under anesthesia is considered the best method of predicting hip stability. Fragment size, which can be calculated using the Keith, Moed, or Calkins method, can be used to predict hip stability radiographically, however they are not as accurate. In general it is thought that posterior wall fractures involving less than 20% of the posterior wall are stable, whereas those involving greater than 40%-50% are unstable. Unfortunately, this leaves an indeterminent zone (20-40%) which does not provide guidance in treatment.

Moed et al retrospectively reviewed 33 patients with posterior wall fractures who underwent dynamic fluoroscopic stress testing and compared the results of this testing to the Moed, Calkins, and Keith method of hip stability prediction. They found that the Moed method is the only reliable technique that is predictive of hip stability for small fracture fragments while also being predictive of instability for large fracture fragments. However, they also stated that there remain a substantial number of fractures involving 20% or more of the posterior wall that are both stable and unstable by examination under anesthesia. Therefore, they recommend dynamic fluoroscopic examination for assessment of hip stability in the presence of a posterior wall fracture.

Tornetta et al conducted a study in which dynamic fluoroscopic stress views were taken of 41 acetabular fractures that met the criteria for non-operative management to determine subtle signs of instability. Of the 41 fractures, 38 were found to be stable and 91% of these had good or excellent outcomes at 2.7 years. They concluded that dynamic stress views can identify subtle instability in patients who would normally be considered for non-operative treatment.

incorrect answers:

1-> Keith Method - Depth of the fracture segment in injured hip is compared to the contralateral intact posterior wall depth at the level of the fovea

2-> Moed - Depth of the fracture segment in the injured hip is compared to contralateral posterior wall depth at the level of the greatest amount of fracture involvement

3-> Calkins - Length of posterior acetabular arc from each hip is compared at the level of the greatest amount of fracture involvement.


Joint stability is critical for successful nonoperative management of posterior wall acetabular fractures. Recent evidence has established that dynamic fluoroscopic stress examination is the best method to determine joint stability in the setting of a posterior wall fracture. The obturator oblique view allows for the best evaluation of hip joint stability during examination for posterior wall fractures.

Grimshaw and Moed retrospectively reviewed the results of patients with posterior wall acetabular fractures managed nonoperatively after evaluation with dynamic fluoroscopic stress tests. At two year follow up, all had good to excellent Merle dAubigne clinical scores for hip function and no evidence of post-traumatic hip arthritis on AP pelvis radiographs.

Tornetta retrospectively reviewed his results managing patients with dynamic fluoroscopic stress examination for acetabular fractures which met radiographic nonoperative criteria. Good-to-excellent clinical results were seen in 91% of patients managed nonoperatively

Tornetta reviewed management of acetabular fractures and Tornetta and Mostafavi separately reviewed management of hip dislocations. In both articles, emphasis is placed on dynamic examination of posterior wall fractures as instability has been seen with fractures comprising as little as 15% of the posterior wall.

Illustration A demonstrates two fluoroscopic images from a dynamic stress exam of a patient with a posterior wall fracture. The image obtained in the obturator oblique view clearly demonstrates that the femoral head loses congruency with the acetabular dome.

Incorrect Answers:Answers 1 & 2: Posterior wall fragment size less than 40% was historically used as an indirect measure of stability, however measurements of fragment size may be unreliable and instability has been seen with fractures much smaller than 40%Answer 3: A history of hip dislocation was thought to indicate a more unstable fracture. In the level IV study by Grimshaw and Moed, patients with an associated hip dislocation who were stable under stress exam had no significant difference in outcome with nonoperative management.Answer 5: The iliac oblique view is used to evaluate the anterior wall and posterior column. Displacement or instability of the posterior wall would not be seen with this view


The obturator oblique-inlet view, as seen in Illustration A, best demonstrates the position of a supra-acetabular screw or pin relative to the tables of the ilium.

Starr et al review their initial results and technique of closed or limited open reduction and percutaneous fixation of acetabular fractures. They defined two groups of patients who may benefit from this technique; elderly patients with multiple comorbidities to facilitate early mobilization and restore hip morphology, and young patients with elementary fracture patterns and multiple associated injuries.

Starr et al describe their operative technique and outcomes for a case series of 3 patients using percutaneous acetabular fixation to augment open reduction of acetabular fractures. The authors state that, for placement of an anterior colum ramus screw, an iliac oblique-inlet (not obturator oblique-inlet) will ensure that the screw is within the medullary canal of the ramus and does not exit anterior or posterior.

Gardner and Nork describe a technique for placement of a large femoral distractor in the supra-acetabular region to compress displaced posterior pelvic ring injuries. They note that the obturator oblique-inlet view is necessary to view the entire length of the pin as well as to ensure that pin remains in bone.

Incorrect answers:Answer 1: Relationshiop of the screw to the acetabulum is best evaluated with the obturator oblique-outlet view as well as the iliac oblique viewAnswer 2: The iliac oblique view is used to ensure the trajectory of the screw is superior to the sciatic notchAnswer 3: The Obturator oblique-outlet view, otherwise known as the "teepee" or "tear drop" view, is used to identify the start for supra-acetabular implant placementAnswer 4: The gluteal pillar is not utilized as a start point when placing supraacetabular fixation, and the obturator oblique-inlet view would not be ideal to visualize this region of the pelvis

Illustrations:A


Figures A through C depict and AP pelvis and Judet views of a T-type fracture of the right acetabulum. The ilioinguinal approach provides access to the anterior wall and anterior column for fracture fixation, in addition to allowing fixation of the nondisplaced posterior transverse fracture line. The lateral femoral cutaneous nerve (LFCN) is at risk in the superficial part of the dissection. Another option for the approach would be the modified Stoppa, which would also allow excellent access to the anterior column as well as the internal aspect of the iliac wing and quadrilateral plate.

Five basic and 5 associated acetabular fractures.

Incorrect Answers:

Answer 1. Kocher-Langenbeck: access for posterior wall and column fractures

Answer 2. Watson-Jones: anterolateral approach best for the hip, not the anterior column of the acetabulum.

Answer 3. Extended iliofemoral: visualization for both column fractures

Answer 5. Hardinge approach: lateral approach for THA


The patients hip radiograph demonstrates an os acetabuli marginalis superior which is a benign accessory ossification center found in the superior aspect of the acetabulum. This can be commonly confused with an acute fracture or avascular necrosis. Although the os acetabuli marginalis superior occasionally persists into adult life, it usually fuses to the acetabulum by the time an individual reaches age 20.

Caudle et al provide a case report of a a patient with a painful os acetabuli marginalis superior. This was successfully treated with resection of the fragment, and bone grafting. This was noted to be a very unusual source of hip pain in adolescents.

Incorrect Answers

2-The fovea capitis is the depression on the head of the femur where the ligamentum teres inserts. This can appear as a small ossicle on the surface of femoral heads in skeletally immature patients. An example of this is shown in Illustration A.

3-Myositis ossificans is soft tissue calcification which develops after trauma, or more rarely, surgery. An example of myositis ossificans around the hip is shown in Illustration B.

4-Avascular necrosis of the femoral head classically occurs in patient with a history of alcoholism, steroid use, or sickle cell disease. Radiographs can demonstrate femoral head sclerosis, and eventually collapse of the articular surface. An example of femoral head AVN in a patient with sickle cell disease is shown in Illustration C.

5-Acetabular fractures occur in the setting of trauma, and are relatively rare in the pediatric population. An example of a left sided acetabular fracture is shown in Illustration D. Illustration E shows a right sided acetabular fracture through the triradiate cartilage.

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Patient functional outcomes after acetabular fractures have been shown to be related to postoperative hip strength, regardless of surgical approach.

The reference by Borrelli et al evaluated muscle strength and outcomes after acetabular surgery via an anterior approach. They report that hip extension strength was affected least (6%), whereas abduction, adduction, and flexion strength was affected to a greater degree. They note that hip muscle strength after operative treatment of a displaced acetabular fracture directly influences patient outcome.

The reference by Engsberg et al is a review of patients that underwent ORIF of acetabular fractures through anterior or posterior approaches. They report that maximizing hip muscle strength may improve gait, and improvement in hip muscle strength and gait is likely to improve functional outcome. Worsening functional outcomes were correlated with decreased gait kinematics and stride length.

REFERENCES:

1. Borrelli J Jr, Ricci WM, Anglen JO, Gregush R, Engsberg J. Muscle strength recovery and its effects on outcome after open reduction and internal fixation of acetabular fractures. J Orthop Trauma. 2006 Jul;20(6):388-95.PMID:16825963 (Link to Abstract)2. Engsberg JR, Steger-May K, Anglen JO, Borrelli J Jr. An analysis of gait changes and functional outcome in patients surgically treated for displaced acetabular fractures. J Orthop Trauma. 2009 May-Jun;23(5):346-53.PMID:19390362 (Link to Abstract)42. PREFERRED RESPONSE 3

Operative treatment is indicated for most displaced acetabular fractures to allow early ambulatory function and to decrease the chance of post-traumatic arthritis. Among the various surgical approaches, the Kocher-Langenbeck allows direct exposure of both the posterior column and posterior wall. Indications for using this exposure include posterior wall fractures, posterior column fractures, combined posterior wall/posterior column fractures, and simple transverse fractures.

REFERENCES:

1. Routt ML. Surgical treatment of acetabular fractures. In: Browner BD, Jupiter JB, Levine AM, Trafton PG, Krettek C, eds. Skeletal Trauma: Basic Science, Management, and Reconstruction, 4th ed. Philadelphia, PA: WB Saunders; 2009:1171-1218.

2. Smith WR, Ziran BH, Morgan SJ, eds. Fractures of the Pelvis and Acetabulum, 2nd ed. New York, NY: Informa Healthcare Publishers; 2007:362-374.


As reviewed in the referenced article by Starr et al, when placing a retrograde pubic rami screw, the pelvic inlet iliac oblique view will best determine the anteroposterior placement of the screw in the pubic ramus. To ensure placement outside of the joint, the outlet obturator oblique is best, but all other views should be incorporated into determination of the position of fixation, as the corridor for this screw placement is quite narrow.

Illustration A shows a left sided inlet iliac view on a pelvic bone model.

REFERENCES:

1. Riley MC. Fractures of the acetabulum. In: Bucholz RW, Tornetta P, Heckman JD, Koval KJ, Court-Brown CM, eds. Rockwood and Green's Fractures in Adults, 6th ed. Philadelphia, PA: Lippincott Williams & Wilkins; 2006:1665-1715.

2. Starr AJ, Reinert CM, Jones AL. Percutaneous fixation of the columns of the acetabulum: a new technique. J Orthop Trauma. 1998 Jan;12(1):51-8.PMID:9447519 (Link to Abstract)44. PREFERRED RESPONSE 3

Figure A is an AP radiograph of a hip hemiarthroplasty.

Contact pressures from an insturmented hip endoprosthesis can have important implications in both implant positioning and rehabilitation protocols.

Hodge et al implanted a pressure-measuring Moore-type endoprosthesis in a patient who had sustained a displaced fracture of the femoral neck. They used this prosthesis to determine the measurement and telemetry of contact pressures in the hip for 36 months post-operatively. The highest pressure, eighteen megapascals, was recorded while the patient was getting up from a chair using the affected leg and was localized in the posterior superior portion of the acetabulum. This can be important in the post-operative care of acetabular fractures, as patients are at increased risk of loss of fixation with greater acetabular contact forces. Interestingly, peak pressures in vivo were found to be considerably higher than previously measured pressures in vitro.

Incorrect Answers:

1,2,4,5,-These regions of the acetabulum have less contact pressure compared to the posterior superior portion.

REFERENCES:

1. Hertling D, Kessler R. Management of Common Musculoskeletal Disorders: Hip, 4th ed. Philadelphia, PA: Lippincott Williams & Wilkins; 2005:441-486.

2. Hodge WA, Carlson KL, Fijan RS, Burgess RG, Riley PO, Harris WH, Mann RW. Contact pressures from an instrumented hip endoprosthesis. J Bone Joint Surg Am. 1989 Oct;71(9):1378-86.PMID:2793891 (Link to Abstract)45. PREFERRED RESPONSE 4

The "corona mortis" (translated as crown of death) artery is a vascular variant that joins the external illiac and the obturator artery as it crosses the superior pubic ramus. Tornetta et al did a study where "fifty cadaver halves were dissected to determine the occurrence and location of the corona mortis. Anastomoses between the obturator and external iliac systems occurred in 84% of the specimens. Thirty-four percent had an arterial connection, 70% had a venous connection, and 20% had both. The distance from the symphysis to the anastomotic vessels averaged 6.2 cm (range, 3-9 cm)." The corona mortis can be injured in superior ramus fractures and iatrogenically while plating pelvic ring injuries using the ilioinguinal approach.

Illustrations:A

REFERENCES:

1. Tornetta P III, Hochwald N, Levine R: Corona mortis: Incidence and location. Clin Orthop Relat Res 1996;329:97-101PMID:8769440 (Link to Abstract)2. Letournel E, Judet R: Fractures of the Acetabulum, ed 2. New York, NY, Springer-Verlag, 1993, pp 375-381


The radiograph in Figure A shows a transverse acetabulum fracture. The iliopectineal (anterior column) and ilioischial lines (posterior column) are interrupted, revealing bicolumnar involvement; however, this is different than the both column fracture, as a transverse pattern has articular surface still in continuity with the axial skeleton via the sacroiliac joint.

The referenced article by Patel et al showed a wide variation of inter and intra-observer agreement in interpreting radiographs of acetabular fractures, with high agreement for basic radiographic classification and only slight to moderate agreement for other radiologic variables such as impaction.

The other referenced article by Letournel is a great review article regarding the initial classification of these fractures as well as a quick summary of his outcomes.

REFERENCES:

1. 2. Letournel E: Acetabulum fractures: Classification and management. Clin Orthop Relat Res 1980;151:81-106PMID:7418327 (Link to Abstract)2. Patel V, Day A, Dinah F, et al: The value of specific radiological features in the classification of acetabular fractures. J Bone Joint Surg Br 2007;89:72-76PMID:17259420 (Link to Abstract)47. PREFERRED RESPONSE 4

The pelvic spur sign is indicative of a both column acetabular fracture. It is best seen on an AP or obturator oblique x-ray. The spur is the intact portion of the ilium, still attached to the axial skeleton and seen posterosuperior to the displaced acetabulum (typically medially displaced).

Illustration A shows the spur sign (arrows) on a CT image, while illustration B shows an obturator oblique of the pelvis and the spur sign is shown with the long tailed arrow (on the left of the image).

Illustrations:A & B

REFERENCES:

1. Letournel E, Judet R: Fractures of the Acetabulum, ed 2. Berlin, Heidelberg, Germany, Springer-Verlag, 1981

2. Vrahas MS, Tile M: Fractures of the acetabulum, in Bucholz RW, Heckman JD (eds): Rockwood and Greens Fractures in Adults, ed 5. Philadelphia, PA, Lippincott Williams & Wilkins, 2001, pp 1513-1545


CT scanning is indicated in acetabular fractures for determination of surgical approach and techniques, evaluation of marginal impaction and presence of intra-articular loose bodies (especially after hip dislocation), and evaluation of fracture piece sizes and relative positions.

Kellam et al reviewed their initial experience with CT scanning and acetabular fractures, and noted a 25% change in surgical planning when CT was utilized versus plain radiographs; they also noted the ability to detect marginal impaction and fracture size/position was improved with CT.

REFERENCES:

1. Kellam JF, Messer A. Evaluation of the role of coronal and sagittal axial CT scan reconstructions for the imaging of acetabular fractures. Clin Orthop Relat Res. 1994 Aug;(305):152-9.PMID:8050224 (Link to Abstract)2. Letournel E, Judet R: Fractures of the Acetabulum, ed 2. Berlin, Springer-Verlag, 1993, pp 29-61


A both column acetabular fracture is defined as an acetabular fracture with no articular surface in continuity with the remaining posterior ilium (and therefore, axial skeleton). The spur sign is a radiological sign seen with these fractures, and is the posterio-inferior aspect of the intact posterior ilium. The spur sign and other radiographic findings consistent with a both column acetabular fracture can be seen in Illustration A (AP), Illustration B (obturator oblique), and Illustration C (iliac oblique).

Illustrations:ABC

REFERENCES:

1. Letournel E, Judet R: Fractures of the Acetabulum. New York, NY, Springer-Verlag, 1993, pp 253-254

2. Vrahas MS, Tile M: Fractures of the acetabulum, in Bucholz RW, Heckman JD (eds): Rockwood and Greens Fractures in Adults, ed 5. Philadelphia, PA, Lippincott Williams & Wilkins, 2001, pp 1513-1545


Early fixation of acetabular fractures is associated with lesser organ dysfunction, so therefore answer three is not true.

Plaisier et al showed the timing of acetabular and pelvic ring fracture fixation greatly impacted patient outcome. Patients who had fixation within 24 hours of injury showed shorter length of stay in the hospital and ICU (decreased number of ventilator days), improved functional outcomes including a highly likelihood of being discharged to home as opposed to a rehabilitation facility, and lesser organ dysfunction.

The reference by Matta et al is a classic article that shows that patients fixed within 3 weeks of injury showed both a higher rate of anatomical reduction and lower overall complication rate than patients with similar fracture patterns treated after 3 weeks.

REFERENCES:

1. Baumgaertner MR, Tornetta P III (eds): Orthopaedic Knowledge Update: Trauma 3. Rosemont, IL, American Academy of Orthopaedic Surgeons, 2005, pp 271-280

2. Plaisier BR, Meldon SW, Super DM, et al: Improved outcome after early fixation of acetabular fractures. Injury 2000;31:81-84PMID:10748809 (Link to Abstract)3. Matta JM. Fractures of the acetabulum: accuracy of reduction and clinical results in patients managed operatively within three weeks after the injury. J Bone Joint Surg Am. 1996 Nov;78(11):1632-45.PMID:8934477 (Link to Abstract)51. PREFERRED RESPONSE 2

Figures A through D show a comminuted both column acetabular fracture. In this injury, both columns are involved, with the acetabulum losing all connection to the axial skeleton (sacrum). This differentiates it from all other patterns, where at least part of the acetabular cartilage maintains connection to the sacrum.

Figure C shows the ischial spur, which is classically known as the spur sign and most easily seen on the obturator oblique radiograph.

Incorrect Answers:Answer 1: This injury has axial skeleton attachment to the acetabular cartilage through the posterior column.Answer 3: This injury has axial skeleton attachment to the acetabular cartilage through the anterior and posterior columns.Answer 4: This injury has axial skeleton attachment to the acetabular cartilage through the anterior column as well as the posterior column, depending on fracture pattern.Answer 5: This injury has no posterior column involvement, and therefore the posterior column maintains the axial skeleton attachment to the acetabulum.

REFERENCES:

1. Letournel E, Judet R: Associated transverse and posterior wall fractures, in Letournel F, Judet R (eds): Fractures of the Acetabulum, ed 2. Berlin, Heidelberg, Springer-Verlag, 1993, pp 201-221

2. Reilly MC: Fractures of the acetabulum, in Rockwood and Greens Fractures in Adults, ed 6. Philadelphia, PA, Lippincott Williams & Wilkins, 2006, pp 1665-1714


Borrelli et al examined the intraneural pressure of the sciatic nerve with the hip and knee in various different positions. They found that the "sciatic nerve appeared to exceed published critical thresholds for alterations of blood flow and neural function only when the hip was flexed to 90 degrees and the knee was fully extended." As a result, the leg is typically position with the hip in extension (or minimal flexion) and the knee in about 90 degrees of flexion when performing acetabular surgery via a posterior approach.


The axial CT cut and Judet radiographic view shown reveals a transverse fracture pattern according to the Letournel classification system. This can be determined by the fact that the articular surface of the acetabulum is attached to the intact portion of the ilium, which is connected to the axial skeleton posteriorly through the sacroiliac joint. This differs from a both-column fracture, in which the articular surface of the acetabulum has no attachments to the axial skeleton due to fracture line(s). The axial CT scan also shows a vertical fracture line which is typical of a transverse fracture pattern.

Durkee et al review the classification schemes for these injuries, as well as comment on the importance of quality images (Judet views, CT, etc).

Figures A and B show a transverse acetabular fracture with mild displacement.


Madhu et al showed time to surgery was a significant predictor of radiological and functional outcome for both elementary and associated displaced fractures of the acetabulum. Both anatomic reduction and functional outcome significantly worsened as time to surgery increased. It was found anatomic reduction was more likely when surgery was within 15 days for elementary fracture and 5 days for associated.

Incorrect answers:2: No data exists showing a decrease in heterotopic ossification as time to surgery increases.3: Neurologic injury is more associated with the initial injury.4,5: Multi-organ failure was not commented on, but infection showed a trend towards being more likely with longer time to surgery.


The external iliac and obturator artery anastomose to form the corona mortis. During the Stoppa or ilioinguinal approach to the pelvis, you need to be careful of the corona mortis because the vessels can cause significant bleeding especially if they retract into the pelvis. In the Tornetta et al article, fifty cadaver halves were dissected to determine the occurrence and location of the corona mortis. Anastomoses between the obturator and external iliac systems occurred in 84% of the specimens. Thirty-four percent had an arterial connection, 70% had a venous connection, and 20% had both. The distance from the symphysis laterally to the anastomotic vessels averaged 6.2 cm. The Okcu et al article showed similar results in 150 cadavers: they found vascular anastomoses between the obturator and external iliac systems in 61% of the sides, and anastomotic veins in 52% of the exposures. The mean distance between the anastomotic arteries and the symphysis pubis was 6.4 cm, and 5.6 cm for the communicating veins. There seemed to be no significant difference between genders in the incidence of corona mortis and the distance between communicating vessels and the symphysis pubis.


There are 5 simple and 5 associated fracture types according to the classification system created by Judet and Letournel. The key feature which distinguishes both column fractures from other associated types is that all articular segments are detached from the intact portion of the ilium, which remains attached to the sacrum through the SI joint.

Although the transverse plus posterior wall, T-shaped, and anterior plus posterior hemi-transverse fractures all show involvement of the anterior and posterior columns, they are not both columns because a portion of the articular surface remains in its normal position, attached to intact ilium.

The intact ilium is responsible for the "spur sign" noted most prominently on the obturator oblique radiograph.

Illustration A demonstrates the 10 types of acetabular fractures as created by Judet and Letournel. Illustration B is an example of a both column acetabular fractures as seen on the obturator oblique radiograph.

Illustration A

Illustration B

REFERENCES:

1. Browner BD, Jupiter JB, Levine AM (eds): Skeletal Trauma. Philadelphia, PA, WB Saunders, 1992

2. Kellam and Tile, Fractures of the Pelvis and Acetabulum


The patient described in this question has sustained an insufficiency fracture, with the radiograph showing significant osteopenia with comminution of both columns, the dome and the medial wall. Treatment of this problem should include reduction and fixation of the column(s) and placement of a total hip arthroplasty (THA), with use of flanged and/or custom acetabular components as needed.

The first referenced article by Weber et al reviewed delayed THA in acetabular fractures, and reported a 78% 10-year survival rate, with worse outcomes in patients < 50yrs, males, weight >80kg, and patients with large residual segmental acetabular defects.

The second referenced article by Jiminez et al reviews the the use of THA after acetabular fractures, either in a delayed or acute fashion. He reviews the techniques of reduction and arthroplasty placement.

The third referenced article by Mears reviews acute THA in osteopenic acetabular fractures, with presentation of treatment algorithms and techniques. He reviews available case series on the subject, with a review of the techniques utilized.

REFERENCES:

1. Weber M, Berry DJ, Harmsen WS: Total hip arthroplasty after operative treatment of an acetabular fracture. J Bone Joint Surg Am 1998;80:1295-1305PMID:9759814 (Link to Abstract)2. Jimenez ML, Tile M, Schenk RS: Total hip replacement after acetabular fracture. Orthop Clin North Am 1997;28:435-446PMID:9208835 (Link to Abstract)3. Mears DC. Surgical treatment of acetabular fractures in elderly patients with osteoporotic bone. J Am Acad Orthop Surg. 1999 Mar-Apr;7(2):128-41.PMID:1021782058. PREFERRED RESPONSE 4

Negative outcome factors have been shown to include: increasing patient age, time from injury to surgery (>3 weeks), intraoperative complications, femoral head bone or cartilage injury, and fracture reduction > 1-2mm from anatomic. Choice of surgical approach has not been shown to affect patient outcomes.

The referenced study by Matta evaluated outcomes of displaced acetabular fractures. The overall clinical result was excellent for 104 hips (40 per cent), good for ninety-five (36 per cent), fair for twenty-one (8 per cent), and poor for forty-two (16 per cent). The clinical result was related closely to the radiographic result. These findings indicate that in many patients who have a complex acetabular fracture the hip joint can be preserved and post-traumatic osteoarthrosis can be avoided if an anatomical reduction is achieved.


In the cited study, researchers measured tissue fluid pressure within the sciatic nerve in cadaveric specimens using a pressure transducer. The hip and knee were taken through a combination of ranges and found that the clinically relevant increase in pressure happened with the hip flexed at 90 degrees and the knee fully extended. They concluded that increased intraneural pressure was related to excursion of the nerve as linear distance between the greater sciatic notch and the distal leg increase. Hence, according to the question stem, to avoid traction injury, the reverse position should be implemented (hip extension and knee flexion).


Letournel and Judet developed a schematic representation of the acetabulum as being contained within asymmetric long anterior and short posterior arms of an inverted Y.

On the bony pelvis, the ilioischial component becomes that posterior column and the iliopectineal line becomes the anterior column. The Judet-Letournel classification system is based on this scheme. By careful evaluation of landmarks on a standard AP pelvis radiograph, as well as on 45-degree oblique obturator and iliac views, the extent of injury can be determined accurately.

The AP view usually demonstrates the six fundamental landmarks relatively well as seen in illustration A. The obturator oblique view reveals additional information about the anterior column and posterior wall(see illustration A(B), B). In an obturator oblique view the x-ray beam is centered on and almost perpendicular to the obturator foramen. The iliac oblique view visualizes the posterior column and anterior wall (illustration A(C), C). This view also shows the best detail of the iliac wing as the radiographic beam is roughly perpendicular to the iliac wing. Inclusion of the opposite hip is essential for evaluation of symmetrical contours that may have slight individual variations and to evaluate the width of the normal articular cartilage in each view in a pelvic series (AP, Judet's) .

Illustration A

Illustration B

Illustration C


The radiograph and CT images shown in A-D show an acute both column acetabular fracture with segmental posterior column comminution. For difficult fractures with anterior displacement in which access to the entire anterior column is required, the ilioinguinal or Stoppa approach is ideal. These approaches allow access to the anterior column as far as the symphysis and includes the quadrilateral plate. Most both-column fractures can also be managed through these approaches, but only if the posterior fragment is large and in one piece. In this case, the posterior column is in several pieces and requires either two approaches or an extended approach, such as the iliofemoral. The original description of the ilioinguinal approach makes intraarticular visualization of the hip impossible. If visualization of the joint is required, a T extension of the incision just medial to the anterior-superior iliac spine can be made. Most surgeons accept that the joint is reduced when the fracture lines inside the pelvis are reduced, and thus this extension is very rarely used.

The extended iliofemoral approach gives excellent visualization of the outer table of the ilium, the superior dome, and the posterior column. The anterior column can be visualized to the iliopectineal eminence. The exposure is similar to that provided by the triradiate approach with the additional benefit of access to the bone above the sciatic notch. The approach can be extended to provide exposure to the iliac fossa; however, this is very rarely necessary and should be avoided. Extending the approach to the inside of the pelvis greatly increases the risk of devascularizing segments of the acetabulum.

REFERENCES:

1. Letournel E, et al (eds). Fractures of the Acetabulum, ed. 2. 1993


Transverse acetabular fractures separate the innominate bone into two fragments, the superior iliac and the inferior ischiopubic, by a single fracture line that crosses the acetabulum horizontally. The iliopectineal and ilioischial lines are disrupted on the AP pelvis radiograph. Axial CT scan of this fracture pattern at the level of the dome will show a vertical anterior to posterior fracture line. Illustrations A-C show AP and Judet pelvic radiographs of a transverse fracture. Illustration D demonstrates the axial CT appearance of this fracture type. Answer choice 2 is describing a both column injury, and answer choice 3 describes a T-type fracture pattern. Answer choices 4 and 5 describe an anterior column and posterior column injury respectively. Judet et al provide one of the first comprehensive reviews on acetabular surgical approaches, fracture types, and radiographic anatomy. Illustration E demonstrates the acetabular classification scheme developed by Judet.

Illustrations:ABCDE

REFERENCES:

1. Letournel E, Judet R (eds): Fractures of the Acetabulum, ed 2. Berlin, Germany, Springer Verlag, 1993.

2. 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 Dec;46:1615-46.PMID:14239854 63. PREFERRED RESPONSE 2

The images demonstrate a posterior column acetabular fracture. These are best surgically treated with a Kocher-Langenbeck approach, which allows access to the posterior column and posterior wall. Figure A shows disruption of the ilioischial line with an intact iliopectineal line which is diagnostic of this fracture pattern. The CT image in Figure D shows the characteristic horizontal (coronal) orientation of the column fracture when viewed on an axial CT. Illustration A shows the radiographic landmarks used in diagnosing acetabular fractures. Illustrations B and C show the orientation of column and wall fractures respectively. Ilioinguinal and Stoppa approaches allow access for anterior column fixation and symphysis fixation respectively. The extended iliofemoral approach can be used to treat both column injuries, but has high rates of post-operative heterotopic ossification.

Illustrations:ABC


Moed et al performed a study to determine the clinical outcome in patients in whom a displaced fracture of the posterior wall of the acetabulum had been treated by open reduction and internal fixation. They were able to show good to excellent clinical results for patients who underwent anatomic reduction and internal fixation of posterior wall acetabulum fractures as assessed using radiographs. Fractures in elderly patients and patients who sustained extensive comminution were more likely to have worse clinical result.

In a separate study, Moed et al. evaluated the results of 67 patients who underwent ORIF of a posterior wall fractures by assessing the accuracy of postoperative AP pelvis, obturator oblique films, iliac oblique films, and CT scans. They found that postoperative pelvic CT scan was the most accurate way to judge final fracture reduction and was able to pick up residual fracture displacements that were not seen on postoperative plain radiographs. They concluded that the accuracy of reduction as assessed on postoperative CT scan was the most reliable indicator of clinical outcomes.

1)PREFERRED RESPONSE 2

The radiograph shown in Figure A reveals a left hip dislocation, with some obscuring of detail secondary to the trauma backboard. CT scans should be obtained following a hip dislocation to evaluate for fractures or impacted areas of the femoral head or acetabulum, as well as noncongruent reductions and free intraarticular joint fragments.

The referenced study by Brumback et al comments on the importance of post-reduction CT scans and found that 23% of their posterior wall fractures had associated marginal impaction, with 94% of these discovered via preoperative CT scan.

2) PREFERRED RESPONSE 1

Traumatic hip dislocation results from the dissipation of a large amount of energy about the hip joint. Clinically, these forces often are first transmitted through the knee en route to the hip. It is therefore logical to look for coexistent ipsilateral knee injury in patients with a traumatic hip dislocation.

Schmidt, et al, prospectively evaluated the ipsilateral knee of all patients who had a traumatic hip dislocation and found that 93% had abnormalities on MRI of the knee, with effusion (37%), bone bruise (33%), and meniscal tear (30%) being the most common findings. They suggest liberal use of MRI to the ipsilateral knee if injury is suspected.

3) PREFERRED RESPONSE 4

Figure D represents a Pipkin II femoral head fracture, which is defined as a fracture which is superior to the fovea. Differentiation between Pipkin I and Pipkin II fractures can be important, as suprafoveal injuries often require surgical fixation. Illustration A demonstrates the Pipkin fracture types.

Droll et al review femoral head fracture evaluation and treatment. They discuss non-operative indications (typically reserved for Pipkin I injuries) which include an anatomic or near anatomic reduction (15 degrees) was seen in 22% of their patients via CT scan after intramedullary nailing. There was a significant difference depending on the time of surgery, with significantly more malrotation during the night shift. Increased fracture comminution also significantly increased malrotation rates. No significant increases were seen with the other answers listed above.


Ipsilateral femoral neck fractures are seen in 1-9% of femoral shaft fractures and the femoral neck must be properly imaged either preoperatively or intraoperatively in any patient with a femoral shaft fracture. Dedicated hip films, possibly including an internal rotation AP, should be obtained before entering the OR.

Daffner et al reported that in 11 of 20 cases of combined femoral shaft and neck fractures, the initial preoperative radiographs did not demonstrate the femoral neck fracture. Intraoperative fluoroscopy should also be used to evaluate for a femoral neck fracture both before (to evaluate for unrecognized fx) and after (to evaluate for iatrogenic fx) IM nailing.

Tornetta et al also describe using preoperative CT scans to evaluate for a femoral neck fracture and found that they were able to reduce the number of missed ipsilateral femoral neck fractures.


Figure A shows a femoral shaft fracture treated with an antegrade femoral nail. Long term deficits are weakness with knee extension (quadriceps) and hip abduction (glutei muscles).

The referenced study by Kapp et al noted long term quadriceps weakness as well as decreased bone mineral density in the femur (femoral neck by 9%, the lateral cortex by 20% and the medial cortex by 13%). It is unclear whether this is due to the injury, treatment, or a combination of both.

The second referenced study by Archdeacon et al also noted weakness in hip abduction, which showed time dependent improvement. He reports that increased early ipsilateral trunk lean is associated with worse recovery of abduction strength.


In the referenced study by Ricci et al, antegrade femoral nailing was shown to have an increased rate of hip pain as compared to retrograde femoral nailing, while having a similar rate of union, time to union, rate of malalignment, and operative time. Hip pain was signficantly higher in the antegrade nailing group, while knee pain was significantly greater in the retrograde group.

The referenced study by Winquist et al noted a 99.1% union rate with intramedullary nailing.

The referenced study by Moed et al noted a 6% nonunion rate in non-reamed retrograde femoral nailing with nail dynamization at 6-12 weeks and early weightbearing.


According to the study by Egol et al, the average femoral anterior radius of curvature was 120 cm (+/- 36 cm), and currently available femoral nails have a greater radius of curvature (i.e. more straight). This mismatch has been shown to lead to an increased risk of perforation of the anterior distal femur as the nail is impacted into the canal.

The referenced study by Tencer et al noted an increased risk of iatrogenic femoral fracture with anterior starting point >6mm from the anatomic axis. They recommend starting in line with the femoral axis, or just a few millimeters anterior in order to minimize this risk.

Illustration A depicts anterior femoral cortex penetration secondary to nail/femur radius of curvature mismatch.

Illustrations: A


Reamed intramedullary femoral nailing is associated with a higher rate of union than nonreamed femoral nailing.

The reference by the Canadian group randomized 224 patients to reamed vs. unreamed femoral nails and found that the relative risk of nonunion was 4.5x greater without reaming, and nonunion was also greater with the use of a small-diameter nail.

The referenced article by Tornetta et al randomized 81 patients to reamed or unreamed nails and found more intraoperative technical complications in the group without reaming. There was no statistical difference in OR time, transfusion requirement or pulmonary complications between the groups. This study showed the overall union rate was similar but when they selected out distal femur fractures, the reamed group healed faster.

The reference by Brumback et al is a review of reamed v. nonreamed nailing, with discussions of reaming techniques and the importance of proper reamer technology and usage.


Patients with retrograde femoral nails commonly have knee pain, while antegrade nails commonly have hip pain, abductor weakness and heterotopic ossification of the abductors.

Ostrums randomized prospective study of 100 patients with reamed femoral nails found 22% of antegrade nail patients had proximal hip pain, weak hip abductors or trendelenburg gait. No significant difference was found in set-up time, operative time, knee motion or pain, or infection rates.

Ricci performed a retrospective study of 293 fractures and found that the antegrade femoral nail group had more hip pain (10% vs 4%) and the retrograde nail group had more knee pain (36% vs 9%). There was no difference in healing, malunion, non-union or other complications.

Tornetta performed a randomized controlled comparison of 69 femur fractures and found more problems of length and rotation using a retrograde nailing. There was no difference in time to union, operating time, blood loss, complications, size of nail or reamer, or transfusion requirements.


Heterotopic ossification (HO) prophylaxis with indomethacin has been shown to increase the risk of long-bone nonunion.

Indomethacin therapy has been shown to be an effective means of preventing HO formation, however literature has shown that it increases the risk of long bone and acetabular nonunion. Indomethacin works primarily by inhibiting IGF-1, which is a different mechanism from other NSAID's which typically inhibit the COX enzymes. IGF-1 is important for bone healing, and its inhibition may be a risk factor for delayed bone healing.

Burd et al performed a study to determine if patients with an acetabular fracture, who received indomethacin for prophylaxis against HO, were at risk of delayed healing or nonunion of any associated fractures of long bones. The study group consisted of 112 patients who had sustained at least one concomitant fracture of a long bone; of which 36 needed no prophylaxis, 38 received focal radiation and 38 received indomethacin. When comparing patients who received indomethacin with those who did not, a significant difference was noted in the rate of long bone nonunion (26% vs 7%).

Jordan et al performed a study to document the efficacy of variable treatment durations with indomethacin prophylaxis for HO and its effect on union of the PW in operatively treated acetabular fractures. Patients were randomly assigned to one of four treatment groups: (1) placebo for 6 weeks, (2) 3 days of indomethacin followed by placebo for a total of 6 weeks, (3) 1 week of indomethacin followed by 5 weeks of placebo, and (4) 6 weeks of indomethacin and followed for 1 year. The authors concluded that the use of prophylactic postoperative indomethacin increases the incidence of symptomatic nonunion of the PW as assessed by CT scan and pain VAS.

Incorrect Answers:

2-Based on the Jordan et al reference, indomethacin increases the risk of posterior wall nonunion

3-There is no evidence that treatment with indomethacin decreases time to union

4-There is no definitive evidence that indomethacin is superior to radiation in the prevention of HO. Recent data actually is in favor of radiation treatment both to prevent nonunion, and its superiority in preventing HO formation.

5-Indomethacin increases the risk of nonunion, which would therefore increase the need for re-operation.


Usage of a piriformis (straight) nail through a greater trochanteric entry portal will bring the fracture into varus, as the greater trochanteric entry site's axis is lateral to the femoral shaft, and advancement of the nail causes the two axes to become colinear, leading to varus. The referenced study by Ostrum notes that usage of a greater trochanteric starting point is safe in obese patients; he recommends usage of a larger incision and maximum leg adduction.

The referenced study by Winquist et al is a classic review of femoral nailing, and emphasizes the importance of starting point selection and fracture reduction to maximize clinical outcomes (99.1% union rate in their series of 520 patients).


The greatest amount of injury to hip abductor musculature is seen with piriformis starting points as compared to the other options listed above. Increased rate of injury to the piriformis tendon, medial femoral circumflex artery branches, gluteus minimus, and superior gluteal nerve branches are noted with the piriformis starting site. Increased injury to the gluteus medius is seen with a greater trochanteric starting point.

The referenced study by Dora et al noted increased injury to the piriformis tendon with a piriformis starting point (as compared to a more lateral insertion site).

The classic referenced article by Johnson et al notes that anterior placement of the starting point >6mm over the recommended start leads to increased hoop stresses and possible burst-type fractures.

The classic referenced study by Winquist et al reviewed their series of 520 femur fractures treated by antegrade nailing; they report a 99.1% union rate.

Illustrations: A


Ipsilateral femoral neck and shaft fractures occur in high energy injuries, with a reported incidence of 2.5-9%. The diagnosis of neck fracture is delayed in 19%-31% of patients. The neck fracture line is almost vertical and nondisplaced, or minimally displaced in 26% to 59% of cases. Two major complications, AVN of the femoral head and non-union of the neck result from neck fracture; therefore, it takes precedence. Dedicated protocols of femoral neck frac

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