The Lateral Stress Radiograph Identifies Occult Instability of Lateral Compression Pelvic Ring Injuries Without Sedation

Standardization and Reproducibility of Dynamic Stress Testing for Occult Pelvic Ring Instability

INTRODUCTION

Examination under anesthesia (EUA) (stress fluoroscopy) is commonly done after pelvic ring injury to identify occult instability because unstable disruptions may displace causing morbidity. The force applied during EUA for these injuries has not been standardized. The purpose of this study was to examine the forces used during the EUA by experienced orthopaedic trauma pelvic surgeons.

METHODS

Orthopaedic traumatologists performed simulated EUA on a cadaver at two North American pelvis and acetabular courses using internal rotation (IR), external rotation, and push-pull maneuvers while wearing a handheld dynamometer to measure force. All surgeons used a comparable method, and each performed EUA multiple times. Maximum forces were measured in Newton (N).

RESULTS

Eighteen surgeons participated. Four had been practicing for <5 years, six for 5 to 10 years, six for 11 to 20 years, and two for >20 years. Surgeons applied a force ranging from 40.4 to 374.9 N during IR, 72.9 to 338.4 N during external rotation, and 25 to 323 N during push-pull, with notable variability seen between surgeons. Three surgeons (18%) had >50-N variability on serial trials of a single EUA maneuver (IR).

DISCUSSION

This is the first study evaluating the forces applied during pelvic EUA used to assess ring stability. Notable variability existed among surgeons performing EUA and in serial examinations by the same surgeon. Additional study is needed to standardize the displacement measured and threshold for instability that guides management.

Stability before and after percutaneous anterior medullary fixation of lateral compression 1 and 2 pelvic ring disruptions: Should surgeons prioritize the anterior ring?

PURPOSE

Surgical intervention for lateral compression (LC) 1 and 2 pelvic ring fractures is controversial. Posterior ring stabilization remains the most common mode of initial fixation. However, greater mechanical instability is observed in the anterior component of LC pelvic fractures. This study tested whether reduction and percutaneous superior ramus fixation will decrease the instability of LC pelvic fractures on intraoperative fluoroscopic imaging.

METHODS

All adult patients (≥ 18 years) presenting with either a Young-Burgess LC1 or LC2 pelvic ring disruption treated operatively with percutaneous anterior followed by posterior fixation by a single surgeon from July 2021 to June 2023 were retrospectively reviewed. Displacement of the anterior ring to intraoperative manual internal rotation stress examination under fluoroscopy was compared before and after anterior pelvic ring reduction and fixation and prior to posterior pelvic ring fixation. Pre- and post-operative visual analog scores (VAS) for pain were also compared.

RESULTS

Twenty-one patients with a mean age of 48.7 years were included. Fifteen patients (71.4%) presented with an LC1, and six (28.6%) with an LC2 injury patterns. Anterior pelvic fixation alone provided 7.5mm reduction in mean displacement of the anterior pelvic ring (pre-operative = 9.2 mm vs. post-operative = 1.6 mm, p < 0.001). VAS significantly decreased from 7.2 one-day pre-operatively to 2.2 twenty-four h post-operatively (p < 0.001).

CONCLUSIONS

Reduction and fixation of the anterior pelvic ring prior to posterior fixation for LC1 and LC2 pelvic ring disruptions substantially improves mechanical stability on intraoperative stress examination. Combination of percutaneous anterior and posterior fixation significantly decreased VAS above the MCID 24 h after stabilization.

Surgical complications after fixation of minimally displaced lateral compression type 1 pelvic ring injuries

PURPOSE

To review surgical complications after fixation of stress-positive minimally displaced (< 1 cm) lateral compression type 1 (LC1) pelvic ring injuries.

METHODS

A retrospective study at a level one trauma center identified patients who received surgical fixation of isolated LC1 pelvic ring injuries. Surgical complications and additional procedures were reviewed.

RESULTS

Sixty patients were included. The median age was 61 years (Interquartile range 40-70), 65% (n = 39) were women, and 57% (n = 34) had high-energy mechanisms. Anterior-posterior, posterior-only, and anterior-only fixation constructs were used in 77% (n = 46), 15% (n = 9), and 8% (n = 5) of patients. Anterior fixation was performed with rami screw fixation in 82% (49/60), external fixation in 2% (1/60), and open reduction and plate fixation in 2% (1/60). There were 15 surgical complications in 23% (14/60), and 12 additional procedures in 17% (10/60). Complications included loss of reduction ≥ 1 cm (8%), symptomatic hematomas (8%), symptomatic backout of unicortical retrograde rami screws (5%), deep infection of the pelvic space after a retrograde rami screw (1.6%), and iatrogenic L5 nerve injury (1.6%). All losses of reduction involved geriatric females with distal rami fractures sustained in ground-level falls. Loss of reduction was found to be more likely in patients with low energy mechanisms (proportional difference (PD) 62%, 95% confidence interval (CI) 18% to 76%; p = 0.01) and 2 versus 1 posterior pelvic screws (PD 36%; CI 0.4% to 75%; p = 0.03).

CONCLUSIONS

Surgical complications and additional procedures routinely occurred after fixation of LC1 injuries. Patients should be appropriately counseled on the risks of surgical fixation of these controversial injuries.

LEVEL OF EVIDENCE

Diagnostic, Level III.

Variables Associated With Loss of Fixation of Retrograde Rami Screws in Minimally Displaced Lateral Compression Type 1 Pelvic Ring Injuries

OBJECTIVES

To evaluate variables associated with loss of fixation of retrograde rami screws in the treatment of stress-positive minimally displaced lateral compression type 1 (LC1) injuries.

METHODS

DESIGN

Retrospective comparative study.

SETTING

Level 1 trauma center.

PATIENT SELECTION CRITERIA

Stress-positive minimally displaced (<1 cm) LC1 pelvic ring injuries treated with retrograde rami screws.

OUTCOME MEASURES AND COMPARISONS

Loss of fixation, defined as >5 mm of pelvic fracture displacement based on the radiographic tear-drop distance or >5 mm of implant displacement on follow-up radiographs; revision surgery for loss of fixation.

RESULTS

Thirty-eight patients with 40 retrograde rami screws were analyzed. Median patient age was 64 years (interquartile range 42.5-73.3 years), 71.1% (n = 27/38) were female, and 52.6% (n = 20/38) of injuries were secondary to low-energy mechanisms. Loss of fixation occurred in 17.5% (n = 7/40) of screws with 10% (n = 4/40) requiring revision surgery. On univariate analysis, patients who had a loss of fixation were more likely to have greater dynamic displacement on stress radiographs (22.0 vs. 15.2 mm; median difference 5.6 mm, confidence interval [CI] -19.2 to 10.3; P = 0.04), unicortical rami screws (71.4% vs. 9.1%; proportional difference 62.3%, CI 8.8%-22.6%; P = 0.001), and partially threaded rami screws (71.4% vs. 21.2%; proportional difference 50.2%, CI 10.0%-77.6%; P = 0.01). The remaining variables had no observed association ( P ≥ 0.05) with loss of fixation, including age, sex, body mass index, energy of injury mechanism, tobacco use, American Society of Anesthesiologist score, sacral fracture type, distal rami fractures, rami comminution, number of sacral screws, fully threaded sacral screws, transsacral screws, or rami screw diameter. On multivariate analysis, only unicortical rami screws ( P = 0.01) remained associated with loss of fixation.

CONCLUSIONS

Retrograde rami screws had a high rate of loss of fixation in minimally displaced LC1 pelvic ring injuries, and this was associated with unicortical screws. These screws should be avoided when possible.

LEVEL OF EVIDENCE

Prognostic Level III. See Instructions for Authors for a complete description of levels of evidence.

Pelvic Ring Injuries: Stable or Not?

Pelvic ring injuries occur in varying severity and in vastly different patient demographics. Knowledge regarding which of these injuries require surgical intervention and which can be managed nonsurgically continues to evolve. Previous studies have shown validated criteria for sacral fractures and the posterior ring, explored the role of examination under anesthesia, and other forms of dynamic imaging. Although there is substantial information available, a comprehensive synthesis of this information is lacking. This article provides a comprehensive review of radiographic markers suggestive of stability, discusses treatment strategies, and proposes a treatment algorithm that is easily understood and applicable to not only those with a trauma background but also the general orthopaedic surgeon who will see these injuries frequently while on call.

Pelvic binder radiography detects occult instability in cadaveric simulated lateral compression type I (LC1) pelvic fractures

OBJECTIVES

Occult instability in minimally displaced lateral compression (LC) pelvic ring injuries may have clinical relevance for treatment. We describe two novel LC pelvis fracture stress examinations - pelvic binder stress radiography (PBR) and pelvic binder stress bladder manometry (PBM) - which do not require sedation, anesthesia, patient transport, or radiation of personnel.

METHODS

A biomechanical study was performed with five fresh elderly cadavers. Sequential osteotomies of the pelvis simulated increasingly unstable LC pelvis fracture patterns (OTA/AO 61A2.2, 61B1.1a, 61B1.1b, 61B2.1). Compressive force was quantitatively applied using a pelvic binder and scale. Pelvis fracture displacement was measured on AP and inlet fluoroscopic views. Pelvic bladder pressure (PBM) was measured using a Foley catheter as a water column.

RESULTS

Fracture displacement strongly correlated with force applied (R2=0.600-0.963). PBR discriminated between simulated LC injuries. Mean displacement of 61B1.1b injuries >1cm was observed at 3.8kg on AP view and 5kg on inlet view. Mean displacement of 61B1.1a injuries >1cm was observed at 8.2kg on AP view and 9.3kg on inlet view. 61A2.2 injuries did not displace >1cm at forces up to 10kg. >95% of 61B1.1a and 61B1.1b injuries displaced >1cm at 10kg. PBM moderately correlated with force applied (R2=0.517-0.842) but did not discriminate between LC injuries.

CONCLUSIONS

PBR is feasible, precisely quantified occult mechanical instability in simulated LC pelvis fractures in response to reproducible applied force, and discriminated between simulated LC pelvis fractures. PBM did not discriminate between simulated LC fractures. A clinical trial to validate the safety and efficacy of PBR for assessing occult instability in LC pelvis fracture is warranted.

Fracture displacement of lateral compression type 1 (LC1) Pelvic Ring Injuries: Which measurement methods are reliable and does displacement correlate with adverse events?

PURPOSE

To determine the interobserver reliability of perceived displacement (PD) ≥ 1 cm of lateral compression type 1 (LC1) pelvic ring fractures and to determine if PD correlated with published methods of measuring fracture displacement and adverse events.

METHODS

The injury and follow-up radiographs of 10 patients with nonoperative minimally displaced LC1 injuries were reviewed by 27 orthopaedic trauma surgeons to determine if they perceived an interval fracture displacement ≥ 1 cm. Perceived displacement (PD) was compared to 11 measurements of displacement: the difference in heights of iliac crests (IC), sourcils, and ischial tuberosities on AP/outlet radiographs; the distance from femoral head (FH) to the sacral midline and the distance between the radiographic teardrops (TD) on the AP; the distance from the TD to sacral midline and the difference in distances between the SI joints and the contralateral TD on the inlet. The interobserver reliability and correlation of PD and measured displacement was calculated. The association between PD and adverse events was also evaluated.

RESULTS

PD had weak interobserver reliability (kappa = 0.46). Many of the measurements of displacement were poorly sensitive for PD. The magnification-corrected AP TD measurement had the highest sensitivity (100%) for PD and excellent interobserver reliability (Intraclass correlation 0.97), but had a low specificity (57.1%). All three patients with PD had adverse events while patients without PD had uneventful recoveries (p = 0.008).

CONCLUSIONS

The AP TD measurement detected all cases of PD and had excellent reliability. PD was associated with adverse events, suggesting that accurate and reliable measurements of displacement are warranted.

LEVEL OF EVIDENCE III

Diagnostic.

Postmobilization Plain Radiography After Lateral Compression Type 1 Pelvic Ring Injury Does Not Affect Treatment

INTRODUCTION

The purpose of this study was to describe the practice of postmobilization radiography after lateral compression type 1 pelvis ring injury. We hypothesized that postmobilization radiographs would be more frequent over time and would not influence treatment.

METHODS

Displacement of pelvis ring injury on initial and final plain radiographs was measured. Frequency of postmobilization radiography was determined, and the impact on treatment and final radiographical outcome were assessed.

RESULTS

Of the 156 patients reviewed, 98 (62.8%) were women and mean age was 60.1 years. Thirty-three of 156 patients (21.2%) had a postmobilization radiograph. Over 5 years, radiographs increased to 67% of presenting patients. None of the patients who received postmobilization plain radiographs (n = 33) had any change in clinical plan afterward; all continued with nonsurgical care. Initial fracture characteristics and alignment were no different for patients with postmobilization radiographs. Final alignment was unchanged in nearly 70%. Overall, 74% of all nonsurgical patients experienced no change in alignment, with similar rates among the patients with postmobilization radiographs.

DISCUSSION

Patients with an lateral compression type 1 fracture demonstrated no changes in care after receiving postmobilization radiographs. However, the frequency of postmobilization radiographs increased over time, denoting opportunities to reduce costs and to improve efficiency and safety.

Early Outcomes of Operative Versus Nonoperative Management of Stress-Positive Minimally Displaced Lateral Compression Type 1 Pelvic Ring Injuries

OBJECTIVES

To compare the early outcomes of patients with stress-positive minimally displaced lateral compression type 1 (LC1b) pelvic ring injuries managed with or without operative fixation.

DESIGN

Retrospective comparison study.

SETTING

Level 1 trauma center.

PATIENTS/PARTICIPANTS

Forty-three patients with LC1b injuries.

INTERVENTION

Operative versus nonoperative.

MAIN OUTCOME MEASUREMENTS

Discharge to subacute rehabilitation (SAR); 2- and 6-week pain visual analog score, opioid use, assistive device use, percentage of normal single assessment numerical evaluation, SAR status; fracture displacement; and complications.

RESULTS

The operative group did not differ in age, gender, body mass index, high-energy mechanism, dynamic displacement stress radiographs, complete sacral fractures, Denis sacral fracture classification, Nakatani rami fracture classification, follow-up length, or American Society of Anesthesiologists classification. The operative group was less likely to be using an assistive device at 6 weeks [observed difference (OD) -53.9%, 95% confidence interval (CI) -74.3% to -20.6%, OD/CI 1.00, P = 0.0005], less likely to remain in an SAR at 2 weeks (OD -27.5%, CI, -50.0% to -2.7%, OD/CI 0.58, P = 0.02), and had less fracture displacement at follow-up radiographs (OD -5.0 mm, CI, -9.2 to -1.0 mm, OD/CI 0.61, P = 0.02). There were no other differences in outcomes between treatment groups. Complications occurred in 29.6% (n = 8/27) of the operative group compared with 25.0% (n = 4/16) of the nonoperative group resulting in 7 and 1 additional procedures, respectively.

CONCLUSIONS

Operative treatment was associated with early benefits over nonoperative management, including shorter time using assistive devices, less SAR use, and less fracture displacement at follow-up.

LEVEL OF EVIDENCE

Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.

Post Post-Mobilization Films for LC1 Pelvic Ring Injuries: Follow up Stress Imaging Demonstrates Minimal Utility

OBJECTIVE

To assess the utility of outpatient postmobilization radiographs in the nonoperative treatment of lateral compression type I (LC1) (OTA/AO 61-B1) pelvic ring injuries.

DESIGN

Retrospective series.

SETTING

Academic, Level 1 trauma center, 2008-2018.

PATIENTS/PARTICIPANTS

A series of 173 patients with nonoperatively treated LC1 pelvic ring injuries was identified. Of these, 139 received a complete set of outpatient pelvic radiographs with which to assess displacement.

INTERVENTION

Outpatient pelvic radiographs to assess additional fracture displacement and potential need for surgical intervention.

MAIN OUTCOME MEASUREMENTS

Rate of conversion to late operative intervention based on radiographic displacement.

RESULTS

No patient in this cohort received late operative intervention. A majority of the patients sustained incomplete sacral fractures (82.6%) and unilateral rami fractures (75.1%), and 92.8% demonstrated less than 10 mm of displacement on their final radiographs.

CONCLUSIONS

There is a low utility of repeat outpatient radiographs of stable, nonoperative LC1 pelvic ring injuries as they do not undergo late displacement.

LEVEL OF EVIDENCE

Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.

Nonoperative management of minimally displaced lateral compression type 1 (LC1) injuries with comminuted rami fractures is associated with late displacement

PURPOSE

Rami comminution has been found to be predictive of lateral compression type 1 (LC1) injury instability on examination under anesthesia (EUA) and lateral stress radiographs (LSR). The purpose of this study was to evaluate how rami comminution and subsequent operative vs. nonoperative management impact the late displacement of these injuries.

METHODS

Retrospective review of a prospectively collected LC1 database was performed to identify all patients with minimally displaced LC1 injuries (< 1 cm) and follow-up radiographs over a four-year period (n = 125). Groups were separated based on the presence of rami comminution and subsequent management, including rami comminution/operative (n = 49), rami comminution/nonoperative (n = 54), and no comminution/nonoperative (control group, n = 22). The primary outcome was late fracture displacement, analyzed as both a continuous variable and as late displacement ≥ 5 mm.

RESULTS

As a continuous variable, late fracture displacement was lower in the comminuted rami/operative group as compared to the comminuted rami/nonoperative group (PD: -3.0 mm, CI: -4.8 to -1.6 mm, p = 0.0002) and statistically non-different from control. Late displacement ≥ 5 mm was significantly more prevalent in the comminuted rami/nonoperative group than in the comminuted rami/operative and no comminution/nonoperative groups (control)(PD: -33.9%, CI: -49.0% to -16.1%, p = 0.0002 and PD: -30.0%, CI: -48.2% to -6.5%, p = 0.02, respectively).

CONCLUSION

Late fracture displacement was greatest in the group with rami comminution/nonoperative management. Rami comminution, which has been previously associated with dynamic displacement on EUA and LSR, is also associated with a higher incidence of late displacement when managed nonoperatively.

LEVEL OF EVIDENCE

Level III, prognostic retrospective cohort study.

Does sequential examination under anaesthesia provide a reliable method to determine a management plan for unstable lateral compression pelvic ring injuries? a prospective study

PURPOSE

To assess the reliability of sequential examination under anaesthesia (EUA) to determine pelvic instability and to evaluate radiological and functional outcomes in unstable lateral compression (LC) injuries.

METHODS

A prospective case series study was conducted from 2020 to 2022 at a university hospital on 43 cases with LC injuries that met the inclusion criteria. Sequential EUA was carried out in three steps. Posterior-only fixation or anterior-posterior fixation was done according to the algorithm. Each patient was followed up for at least 12 months, both radiologically and functionally.

RESULTS

Forty cases proved unstable and were fixed. None showed secondary displacement in the anterior-posterior fixation group. However, five cases (19.2%) of the posterior-only fixation group showed secondary displacement with a mean of 5.9 mm. Four cases of them had tetra-ramic injuries. There is a high tendency for secondary displacement at 14.5 mm or more preoperative displacement of the rami. Patients with secondary displacement showed comparable functional outcome scores to patients without secondary displacement. Posterior-only fixation showed shorter operative time, lesser radiological exposure, blood loss and iatrogenic nerve injury than anterior-posterior fixation.

CONCLUSION

EUA is a reliable method to determine pelvic instability and management plan for LC fractures with unilateral anterior ring injury. Anterior-posterior fixation is needed if there is a tetra-ramic fracture or initial anterior ring displacement of 14.5 mm or more, irrespective of EUA.

Geriatric Patients Presenting With Isolated Pubic Rami Fractures and Inability to Mobilize May Have Occult Lateral Compression Pelvic Ring Injuries With Dynamic Instability

OBJECTIVES

To determine the incidence of patients with isolated pubic rami fractures on computed tomography scans who have dynamic instability secondary to occult lateral compression pelvic ring injuries.

DESIGN

Retrospective comparison study.

SETTING

Urban level 1 trauma center.

PATIENTS/PARTICIPANTS

This study included geriatric patients with isolated pubic rami fractures and inability to mobilize secondary to pain.

INTERVENTION

Lateral stress radiographs of pelvis to evaluate for ≥1 cm dynamic instability.

MAIN OUTCOME MEASUREMENTS

Physical therapy clearance, hospital length of stay, and discharge location.

RESULTS

A total of 19 patients were identified over 12 months. Patients were predominantly geriatric (median age: 75 years, interquartile range: 67 to 90), woman (11/19), with unilateral (17/19) comminuted distal rami fractures (12/19) sustained in ground-level falls (12/19). Dynamic instability was identified in 42% of patients (8/19). Magnetic resonance imaging, obtained in 6 of these patients, demonstrated occult posterior ring fractures in all cases. Patients with dynamic instability were more likely to have comminuted distal rami fractures (Nakatani type 1b) and a longer hospital length of stay. There was also a trend for these patients to be unable to clear physical therapy by discharge (63% (5/8) versus 36% (4/11)). The 90-day mortality rate of the cohort was 16% (3/19).

CONCLUSIONS

Patients presenting with seemingly isolated pubic rami fractures on radiographs and computed tomography scans who are unable to mobilize may have occult lateral compression injuries with dynamic instability.

LEVEL OF EVIDENCE

Diagnostic Level III. See Instructions for Authors for a complete description of levels of evidence.

Surgical stabilisation in equivocal pelvic ring injuries - Into the grey zone

Pelvic ring injuries comprise a spectrum of bony, ligamentous and muscular injuries, described by several common classification systems. However, the majority of injuries lie in areas of intermediate severity, where complexity and variable nature make it extremely hard to define in detail. This fact and associated injuries make it extremely difficult to conduct randomised control trials, with purpose to direct treatment guidelines. Thus, special interest and expertise are required by pelvic trauma surgeons, while surgical indications and fixation methods rely on their experience, at least in part. Namely, a significant grey zone of indication exists. As fixation methods evolve, specifically percutaneous fixation using osseous fixation pathways, some injuries in which morbidity bound with surgical fixation was considered too high relative to its benefits, may be considered eligible for surgical treatment nowadays. Moreover, due to significant progress in the treatment of the acute polytrauma casualties, the survival rate increased over the years, emphasizing the effect of long-term morbidity and functional outcome of pelvic ring injuries. The purpose of this manuscript is to describe the equivocal areas of controversies, hence "the grey zone", and to provide the readership with up-to-date published data. We aimed to collect and detail clinical and radiological clues in the diagnosis of intermediate unstable anterior-posterior compression and lateral compression injuries, and for the selection of treatment methods and sequence. Recent publications have provided some insights into specific injury features that are correlated with increased chance of instability, pain and delay in ambulation. Specific focus is given to the utility of examination under anaesthesia in selected cases. Other publications surveyed the shared experience of pelvic trauma surgeons as for the classification, indication and treatment sequence of pelvic ring injuries. Although the data hasn't matured yet to a comprehensive treatment algorithm, it may serve clinicians well when making treatment decisions in the grey zone of pelvic ring injuries, and serve as a basis for future prospective studies.

The EMS stress view: occult pelvic instability revealed by pre-hospital pelvic binder placement

PURPOSE

To describe and evaluate the serendipitous pelvic binder stress radiographs of lateral compression type (LC) pelvic ring injuries.

METHODS

This was a retrospective case series performed at a single, level I academic trauma center from 2016 to 2018. All patients presenting with a minimally displaced LC pelvic ring injury were reviewed (< 10 cm displacement on static pelvic radiographs). Patients with X-rays (XR) in a pelvic binder (EMS stress) and with the pelvic binder removed were included. Pelvic ring stability was determined by attending surgeon evaluation of EMS stress radiographs versus static XR of the pelvis. Patients were treated non-operatively and allowed to weight bear or taken to the operating room for exam under anesthesia (EUA) and potential operative fixation. Clinical success of treatment was determined by evaluation of further displacement at the completion of their most recent follow-up.

RESULTS

Thirty-seven patients of the initial 398 reviewed met inclusion criteria. Fourteen of 37 patients (38%) were categorized as stable with no significant pelvis displacement seen on EMS stress and were treated non-operatively without further sequelae (4.6 months mean follow-up). The remaining 23/37 (62%) were treated operatively. Occult instability was identified on EMS stress in 14 (61%) of those 23 patients and the remainder were determined to be unstable based upon fracture pattern or EUA. All patients went on to successful treatment without significant pelvic deformity (7.8 months mean follow-up).

CONCLUSION

The EMS stress XR is a valuable, opportunistic evaluation in LC pelvic ring injuries. This evaluation is a useful diagnostic adjunct to alert the provider that additional stress imaging may be indicated to evaluate for occult pelvic ring instability.

Pelvic ring injuries: recent advances in diagnosis and treatment

Pelvic ring injuries typically occur from high-energy trauma and are often associated with multisystem injuries. Prompt diagnosis of pelvic ring injuries is essential, and timely initial management is critical in the early resuscitation of polytraumatized patients. Definitive management of pelvic ring injuries continues to be a topic of much debate in the trauma community. Recent studies continue to inform our understanding of static and dynamic pelvic ring stability. Furthermore, literature investigating radiographic and clinical outcomes after nonoperative and operative management will help guide trauma surgeons select the most appropriate treatment of patients with these injuries.

Evaluation of anterior translation in total knee arthroplasty utilizing stress radiographs

BACKGROUND

Flexion instability is a common cause for revision after total knee arthroplasty (TKA); however, little objective criteria exist to determine excessive laxity in flexion. This study sought to determine the reliability of stress radiographs for flexion laxity using manual stress as well as a commercially available flexion stress device, with the hypothesis that a commercially available force device would provide increased translation compared to manual stress, and radiographic measurements would be reproducible.

METHODS

Ten patients who previously underwent TKA with non-hinged components were prospectively and consecutively enrolled at a single center to undergo stress radiographs. Three lateral radiographs with the knee at 90° of flexion were obtained for each patient: rest, commercial stress device at 150N, and manual stress. Calibrated radiographs were evaluated by two raters, and inter-rater and intra-rater reliability were determined using intraclass correlation coefficients (ICC).

RESULTS

Ten patients (seven female) with mean age 72 (range 55-82) years and average duration from surgery 36 (range 12-96) months were evaluated. The commercial stress device provided significantly less anterior translation than manual stress (- 0.3 mm vs. 3.9 mm; p < 0.01). Two patients reported pain with use of the stress device. Inter-observer reliability of measurements was good for commercial stress (ICC = 0.86) and excellent for manual stress (ICC = 0.94). Eighty-five percent of measurements were within 1 mm between observers. Intra-observer reliability of measurements was good to excellent for both the stress device and manual stress.

CONCLUSIONS

Lateral stress radiographs may assist in the objective evaluation of flexion instability. A commercially available product provided less translation than manual stress; however, measurements were reliable and reproducible between observers. Further research is required to correlate translation with stress radiographs to patient outcomes following revision arthroplasty.

Surgical treatment of sacral nonunions

Sacral fractures are complex injuries that follow a bimodal distribution, typically involving acute high energy trauma in young adults and low energy trauma in older adults (> 65 years old). Nonunion is a rare but debilitating potential complication of undiagnosed or improperly managed sacral fractures. Various surgical techniques, including open reduction and internal fixation, sacroplasty, and percutaneous screw fixation, have been used to manage these fracture nonunions. In addition to reviewing the initial management of sacral fractures and the risk factors for fracture nonunion, this article describes techniques, specific cases and outcomes of these treatment strategies.

Combined Anterior-Posterior versus Posterior-Only Fixation of Stress-Positive Minimally Displaced Lateral Compression Type 1 (LC1) Pelvic Ring Injuries

OBJECTIVES

To compare hospital outcomes and late displacement between stress-positive minimally displaced lateral compression type 1 (LC1) pelvic ring injuries treated with combined anterior-posterior versus posterior-only fixation.

DESIGN

Retrospective comparative cohort.

SETTING

Urban level-one trauma center.

PATIENTS/PARTICIPANTS

LC1 injuries managed operatively.

INTERVENTION

Anterior-posterior versus posterior-only fixation.

MAIN OUTCOME MEASUREMENTS

Physical therapy (PT) clearance, discharge location, hospital length of stay (LOS), inpatient morphine equivalent doses (MED), and fracture displacement at follow-up.

RESULTS

Groups were similar in demographic and injury characteristics (age, high energy mechanism, ASA score, stress displacement, and rami/sacral fracture classifications). Anterior-posterior fixation resulted in longer operative times (median difference (MD): 27.0 minutes, 95% confidence interval (CI): 17.0 to 40.0, P < 0.0001) and had a trend of increased estimated blood loss (MD: 10 mL, CI: 0 to 30, P = 0.07). Patients with anterior-posterior fixation required less inpatient MEDs (MD: -180.0, CI: -341.2 to -15.0, P = 0.02), were more likely to clear PT by discharge (100% vs. 70%, proportional difference (PD): 30%, CI: 2.0%-57.2%, P = 0.02), were less likely to discharge to rehabilitation facilities (0% vs. 30%, PD: 30%, CI: 2.0%-57.2%, P = 0.02), and had a trend of less days to clear PT after surgery (MD: -1, CI: -2 to 0, P = 0.09) and decreased LOS (MD: -1, CI: -4 to 1, P = 0.17). Late fracture displacement did not differ between groups.

CONCLUSION

Anterior-posterior fixation of LC1 injuries was associated with an improved early hospital course-specifically, reduced inpatient opioid use and an increased number of patients who could clear PT and discharge home.

LEVEL OF EVIDENCE

Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.

Comparing Emergency Department Stress of Lateral Compression Type 1 Pelvis Fractures With a Validated Instability Scoring System

INTRODUCTION

Lateral compression type 1 (LC1) pelvic ring injuries represent a heterogeneous group of fractures with controversial surgical indications. Recently, multiple institutions have suggested the safety and reliability of an emergency department (ED) stress to evaluate for occult instability. The purpose of this study was to correlate ED stress examination of LC1 pelvis fractures against a validated fracture instability scoring system.

METHODS

This was a retrospective review of a consecutive series of 70 patients presenting with minimally displaced LC1 fractures at a level 1 academic trauma center. All patients were stressed in the ED radiology suite, and displacement was measured by comparing calibrated stress radiographs with static radiographs (>10 mm displacement defined positivity). ED stress results were compared with radiographic scores assigned according to the validated Beckmann scoring system (score <7: stable-nonsurgical recommendation; score 7 to 9: indeterminant recommendation; and score >9: unstable-surgical recommendation).

RESULTS

Thirteen patients had a positive ED stress examination, and 57 patients stressed negative. The mean displacement was significantly different between the three groups (Beckmann 5 to 6: 3.31 mm, SD = 2.4; Beckmann 7 to 9: 4.23 mm, SD = 3.2; Beckmann 10+: 12.1 mm, SD = 8.6; P < 0.001). Zero of 18 patients in the stable group stressed positive, and only 3 of 38 patients in the indeterminant group stressed positive (7.9%). Finally, 10 of 14 patients in the unstable group stressed positive (71.4%; P < 0.001). Sacral displacement (P = 0.001), superior ramus location (P < 0.02), and sacral columns (P < 0.001) significantly predicted ED stress positivity in multivariate analysis.

CONCLUSIONS

Comparison of a validated instability scoring system with ED stress examination of minimally displaced LC1 fractures in awake and hemodynamically stable patients showed excellent correlation. This suggests that the ED stress examination is a useful diagnostic adjunct. LC1 fracture characteristics should be analyzed to determine which pelvic fracture characteristics determine occult instability before stress examination.

LEVEL OF EVIDENCE

Level III diagnostic.

Anterior Pelvic Ring Fracture Pattern Predicts Subsequent Displacement in Lateral Compression Sacral Fractures

OBJECTIVE

To determine if anterior pelvic fracture pattern in lateral compression (LC) sacral fractures correlates with subsequent displacement on examination under anesthesia (EUA) or follow-up in both nonoperative and operative cases.

DESIGN

Retrospective cohort study.

SETTING

Level 1 trauma center.

PATIENTS

Two hundred twenty-seven skeletally mature patients with traumatic LC (OTA/AO 61B1.1, 61B2.1-2, and 61B3.1-2) pelvic ring injuries treated nonoperatively, with EUA, or with pelvic fixation were included.

INTERVENTION

The study intervention included retrospective review of patients' charts and radiographs.

MAIN OUTCOME MEASUREMENT

Displacement on EUA or follow-up radiographs (both operative and nonoperative) correlated with anterior pelvic ring fracture pattern.

RESULTS

Independent of sacral fracture pattern (complete or incomplete), risk of subsequent displacement on EUA or at follow-up after both nonoperative and operative treatments correlated strongly with ipsilateral superior and inferior pubic rami fractures that were either comminuted (95.6%, P < 0.001) or oblique (100%, P < 0.001). Patients with transverse or lack of inferior pubic ramus fracture did not displace (0%, P < 0.001). Out of 21 LC injuries treated with posterior-only fixation, displacement at follow-up occurred in all 11 patients (100%) with comminuted and/or oblique superior and inferior pubic rami fractures. Nakatani zone I and II rami fractures correlated most with risk of subsequent displacement.

CONCLUSIONS

Unstable anterior fracture patterns are characterized as comminuted and/or oblique fractures of ipsilateral superior and inferior pubic rami. EUA should be strongly considered in these patients to disclose occult instability, for both complete and incomplete sacral fracture patterns. Additionally, these unstable anterior fracture patterns are poor candidates for posterior-only fixation and supplemental anterior fixation should be considered. Irrespective of sacral fracture pattern (complete or incomplete), nonoperative management is successful in patients with transverse or lack of inferior pubic ramus fractures.

LEVEL OF EVIDENCE

Prognostic Level III. See Instructions for Authors for a complete description of levels of evidence.

Lateral Stress Radiographs of Lateral Compression Type 1 Pelvic Injuries, With the Injured Side Down or Up, Reliably Measure Occult Instability

OBJECTIVES

To evaluate the interobserver reliability of measured displacement and occult instability of minimally displaced lateral compression type 1 (LC1) fractures on lateral stress radiographs (LSRs) and to compare differences in displacement between LSR with the injured side down (ID) and up (IU).

DESIGN

Retrospective review.

SETTING

Urban Level 1 trauma center.

PATIENTS/PARTICIPANTS

Twenty-three adult patients with minimally displaced (&lt;1 cm) LC1 injuries.

INTERVENTION

None.

MAIN OUTCOME MEASUREMENTS

Three orthopaedic surgeons measured the distance between the radiographic teardrops on LSR and supine anteroposterior pelvic radiographs to calculate dynamic fracture displacement. The interobserver reliability of the measured displacement, a continuous variable, was assessed by calculating the intraclass correlation coefficient. The interobserver reliability of occult instability (≥10 mm of displacement on LSR), a categorical variable, was assessed by calculating the kappa value. Matched-pairs analysis was performed to calculate the mean difference of measurements between observers and between ID and IU LSR.

RESULTS

The interobserver reliability of the measured displacement was excellent (intraclass correlation coefficient 0.93). The mean difference in measurements between observers ranged from -1.8 to 0.96 mm. The mean difference in the measured displacement between ID and IU LSRs for each observer ranged from -0.6 to 0.3 mm. There was 83% (19/23 cases) agreement on the presence of occult instability (≥10 mm of displacement on LSR) on both ID and IU LSRs. The interobserver reliability of occult instability was moderate (kappa 0.76).

CONCLUSIONS

Measured fracture displacement and occult instability of minimally displaced LC1 injuries were reliably measured and identified on LSR, regardless of the laterality.

Rami Comminution Is Associated With Displacement of Minimally Displaced Lateral Compression Type 1 Injuries on Lateral Stress Radiographs

OBJECTIVES

To determine whether displacement on lateral stress radiographs (LSRs) in patients with minimally displaced lateral compression type 1 pelvic ring injuries is associated with any demographic and/or injury characteristics.

DESIGN

Retrospective comparative cohort.

SETTING

Urban level 1 trauma center.

PATIENTS/PARTICIPANTS

Ninety-three consecutive patients with minimally displaced lateral compression type 1 injuries.

INTERVENTION

Displacement of pelvic ring injury on LSR (≥10 mm vs. &lt;10 mm).

MAIN OUTCOME MEASUREMENTS

Demographic and injury characteristics (mechanism of injury, Nakatani rami classification, rami comminution, Denis zone, complete/incomplete sacral fracture, sacral comminution).

RESULTS

65.6% of patients (n = 61) had ≥10 mm of displacement on LSR. On univariate analysis, displacement was associated with increased age [median difference 11: confidence interval (CI), 2-23], female sex [proportional difference (PD): 25.1%, CI, 3.9%-44.4%], Nakatani classification (type I PD: 27.9%, type II PD: -19.5%), and rami comminution (PD: 55.6%, CI, 35.4%-71.3%). On multivariate analysis, displacement was only associated with rami comminution (odds ratio: 16.48, CI, 4.67-58.17). Displacement was not associated with energy of injury mechanism, sacral fracture Denis zone, complete sacral fracture, sacral comminution, or bilateral rami fractures.

CONCLUSIONS

Although rami comminution was the only variable found to be independently associated with displacement ≥10 mm on LSR, no single variable perfectly predicted displacement. Future studies are needed to determine whether displacement on stress radiographs should change the management of these injuries.

LEVEL OF EVIDENCE

Prognostic Level III. See Instructions for Authors for a complete description of levels of evidence.

Minimally invasive transiliac anatomical locking plate for posterior pelvic ring injury: A technical trick of the gull wing plate

Posterior pelvic ring injuries commonly involve sacral fractures, which are difficult to reduce and stabilize. Because conservative treatment requires long-term bedrest and leads to unsatisfactory outcomes, surgical intervention is a beneficial option to protect neurological structures and provide sufficient stability for early mobilization. Several studies have investigated a variety of internal fixation techniques, such as iliosacral screws, transiliac bars, spinal instruments, and transiliac plates. The gull wing plate (GWP) is a pre-contoured anatomical locking plate with two cancellous screws (φ6.5 mm) and four locking screws (φ5.0 mm), the design of which is unique among posterior tension-band plates. The GWP provides reliable stability of the posterior construct of the pelvic ring and accelerates rehabilitation. Compared to alternative surgical techniques for posterior fixation, the simple surgical procedure of the GWP is minimally invasive and highly reproducible, which leads to fewer complications and less radiation exposure.

Indications for cement augmentation in fixation of geriatric intertrochanteric femur fractures: a systematic review of evidence

INTRODUCTION

Achieving durable mechanical stability in geriatric intertrochanteric proximal femur fractures remains a challenge. Concomitant poor bone quality, unstable fracture patterns, and suboptimal reduction are additional risk factors for early mechanical failure. Cement augmentation of the proximal locking screw or blade is one proposed method to augment implant anchorage. The purpose of this review is to describe the biomechanical and clinical evidence for cement augmentation of geriatric intertrochanteric fractures, and to elaborate indications for cement augmentation.

METHODS

The PubMed database was searched for English language studies up to January 2021. Studies that assessed effect of calcium phosphate or methylmethacrylate cement augmentation during open reduction and internal fixation of intertrochanteric fractures were included. Studies with sample size < 5, nontraumatic or periprosthetic fractures, and nonunion or revision surgery were excluded. Study selection adhered to PRISMA criteria.

RESULTS

801 studies were identified, of which 40 met study criteria. 9 studies assessed effect of cement augmentation on fracture displacement. All but one found that cement decreased fracture displacement. 10 studies assessed effect of cement augmentation on total load or cycles to failure. All but one demonstrated that augmented implants increased this variable. Complication rates of cement augmentation during ORIF of intertrochanteric fractures ranged from 0 to 47%, while non-augmented implants ranged from 0 to 51%. Reoperation rates ranged from 0 to 11% in the cement-augmented group and 0 to 11% in the non-augmented group. Fixation failure ranged from 0 to 11% in the cement-augmented group and 0 to 20% in the non-augmented group. Nonunion ranged from 0 to 3.6% in the cement-augmented group and 0 to 34% in the non-augmented group.

CONCLUSIONS

Calcium phosphate or PMMA-augmented CMN fixation of IT fractures increased construct stability and improved outcomes in biomechanical and early clinical studies. The findings of these studies suggest an important role for cement augmentation in patient populations at high risk of mechanical failure.

The lateral stress radiograph: an effective alternative to examination under anesthesia for identifying occult instability in minimally displaced lateral compression pelvic ring injuries

PURPOSE

The purpose of this study was to review the practice of utilizing lateral stress radiographs (LSRs) to identify occult instability (≥ 10 mm of dynamic displacement on LSRs) of minimally displaced lateral compression type 1 (LC1) pelvic ring injuries and to evaluate for associations between instability and patient demographics, injury characteristics, and hospital course.

METHODS

A retrospective review of a prospective registry from 2018 to 2022 identified 151 patients with LC1 injuries. LSRs were obtained in 86.8% (131/151) of patients. Three (2.2%) patients were excluded for malrotation of LSRs, leaving 128 patients for analysis.

RESULTS

The median maximum dynamic displacement on LSRs was 12.2 mm (IQR: 5.9 to 17.3). Occult instability was present in 62.5% (80/128) of patients and was associated with older age (Median difference 11.0 years, 95% CI 3.0 to 20.0), Nakatani type 1 rami fractures (73.7% vs. 47.9%, p = 0.001), and rami fracture comminution (Proportional difference 58.7%, 95% CI 42.8 to 71.3%), but not gender, high-energy mechanism, bilateral rami fractures, Denis classification, sacral fracture completeness, or sacral comminution. Patients with occult instability took longer to ambulate 15 feet and clear physical therapy (PT), were more likely to be unable to clear PT by hospital day 3 or by time of discharge, had longer hospital stays, and were more likely to require rehabilitation facilities.

CONCLUSION

LSRs were obtained in a majority of patients. Occult instability was frequently present and associated with older age, comminuted distal pubic rami fractures, longer hospital stays, longer times to mobilize and clear PT, and an increased need for rehabilitation facilities.

The effect of pelvic ring rotation and tilt on the radiographic teardrop distance: an important consideration in the assessment of dynamic displacement on stress radiographs

PURPOSE

The purpose of this study was to determine the effect of rotation and tilt on the radiographic teardrop distance (TD) on anteroposterior (AP) pelvis radiographs.

METHODS

Radiographic examination of a pelvis models was conducted utilizing increasing degrees of beam rotation and tilt on portable C-arm fluoroscopy. The TD, x-plane rotation (symphyseal-mid-sacrum distance (SMS)), and y-plane tilt (sacroiliac joint-symphysis distance (SIS)) were measured by four independent observers. Interobserver reliability was assessed using intraclass correlations.

RESULTS

TD was altered by less than 2 mm with up to 7.5° fluoroscopic rotation (SMS: 3 cm) and up to 30° of inlet and 15° of outlet (SIS: ± 3.3 cm). SMS distance effectively corresponded to the degree of rotation present (r = 1.00, CI: 0.97 to 1.00, p < 0.0001) and was strongly correlated to TD (r = -0.95, CI: -0.99 to -0.67, p = 0.001). SIS distance effectively corresponded to the degree of tilt present (r = -0.97, CI: -0.99 to -0.88, p < 0.0001) and was correlated to TD (r = 0.94, CI: 0.75 to 0.99, p = 0.0001). Linear regression models determined that, with every degree of rotation and tilt, TD was altered by 0.4 mm and 0.09 mm, respectively (p = 0.0004, r² = 0.93 and p < 0.0001, r² = 0.94, respectively). Interobserver reliability among observers was excellent (0.92).

CONCLUSION

The TD has excellent interobserver reliability and is minimally impacted by up to 7.5° of rotation, 30° inlet tilt, and 15° of outlet tilt. Utilization of these thresholds may ensure reliability of TD measurements when assessing pelvis stress radiographs.

Pelvic ring injuries after alpine ski and snowboard accidents

PURPOSE

The purpose of this study was to analyze the patient/injury characteristics and associated hospital course of patients sustaining traumatic pelvic ring injuries after alpine ski and snowboard accidents at a level one trauma center in the Rocky Mountain region.

METHODS

Patient/injury characteristics were obtained from patients presenting with pelvic ring injuries after alpine ski (n = 55) and snowboard (n = 9) accidents. Characteristics and outcomes analyzed included mechanism of injury, pelvic ring classification (Young-Burgess and Tile), hospital admission, physical therapy (PT) clearance, ambulation, length of stay, inpatient morphine milligram equivalents (MME), and discharges to rehabilitation facility.

RESULTS

Snowboarders were more often younger, male, tobacco/substance users, and more likely to be injured by a fall from height than skiers. There were no differences in injury classification or hospital course outcomes between alpine sports. Most common injuries included lateral compression type 1 (LC1) injuries (37.5%), isolated pubic ramus fractures (31.3%), and isolated iliac wing fractures (15.6%). LC1 injuries were unstable in 50% of cases and associated with increased admissions (proportional difference: 47.5%, CI: 23.8-64.5%, p = 0.0002), longer time to PT clearance (median difference(MD): 1.0 day, CI: 0-2.0, p = 0.03), longer LOS (MD: 2.0, CI: 0-2.0, p = 0.02), and increased inpatient MMEs (MD: 197.9 MME, CI: 30.0-420.0, p = 0.02), as compared to other pelvic ring injuries.

CONCLUSION

The majority of pelvic ring injuries from alpine ski and snowboard accidents were LC1 injuries, half of which were unstable, resulting in longer hospital stays, time to PT clearance/ambulation, and opioid use.

Nonoperative Management of Minimally Displaced Lateral Compression Type 1 Pelvic Ring Injuries With and Without Occult Instability

OBJECTIVES

To determine the association of pelvic fracture displacement on lateral stress radiographs (LSRs) with the hospital course of patients with minimally displaced lateral compression type 1 (LC1) pelvic injuries.

DESIGN

Retrospective review.

SETTING

Level 1 trauma center.

PATIENTS/PARTICIPANTS

Twenty-eight adult patients with minimally displaced (<1 cm) LC1 injuries.

INTERVENTION

Nonoperative management.

MAIN OUTCOME MEASUREMENTS

Delayed operative fixation, days to clear physical therapy, mobilization, hospital length of stay, and total hospital opioid morphine equivalent dose.

RESULTS

LSR displacement was correlated with delayed operative fixation [r = 0.23, 95% confidence interval (CI) 0.05-1.11; P = 0.01], days to clear PT (r = 0.13, CI 0.01-0.28; P = 0.02), length of stay (r = 0.13, CI 0.006-0.26; P = 0.02), and opioid morphine equivalent dose (r = 19.4, CI 1.5-38.1; P = 0.03). A receiver operating characteristic curve for delayed operative fixation over LSR displacement had an area under the curve of 0.87. The LSR displacement threshold that maximized sensitivity and specificity for detecting patients who required delayed fixation was 10 mm (100% sensitivity and 78% specificity). Ten of the 15 patients with ≥10 mm of displacement on LSRs underwent delayed operative fixation for pain with mobilization at a median of 6 days (interquartile range 3.7-7.5). Patients with ≥10 mm of displacement on LSRs took longer to clear PT, took longer to walk 15 feet, had longer hospital stays, and used more opioids.

CONCLUSIONS

LC1 fracture displacement on LSRs is associated with delayed operative fixation, difficulty mobilizing secondary to pain, longer hospital stays, and opioid use.

LEVEL OF EVIDENCE

Prognostic Level III. See Instructions for Authors for a complete description of levels of evidence.

Indications for surgical fixation of low-energy pelvic ring fractures in elderly: a systematic review

INTRODUCTION

There are no generally accepted criteria for when and how to fixate osteoporotic pelvic ring fractures in elderly. This systemic review aims to summarize the currently available literature regarding the indications and methods for surgical fixation of fragility fractures of the pelvic ring in elderly patients after low-energy trauma.

MATERIALS AND METHODS

The Pubmed and Embase databases were searched using the key words pelvic fractures, geriatric, fragility, osteoporosis, and surgical fixation, and their synonyms. Extracted data including the indication, method of operative fixation, and post-operative outcomes (pain levels, mobility, complications and mortality) were analyzed using descriptive statistics. The studies were too heterogeneous to perform a meta-analysis.

RESULTS

Eleven cohort studies (3 comparative and 8 noncomparative) were included. The methodological quality was poor to moderate; the studies were heterogeneous regarding study design and reported outcomes. In all included studies operative treatment for all fracture types was preceded by a period of conservative treatment comprising physiotherapy-guided full weight-bearing. Time to surgery differed widely. For posterior ring fixation, the majority of the included studies used minimally invasive surgery with trans-iliosacral screws. Five studies described a form of additional fixation of the anterior pelvic ring but did not report the indications.

CONCLUSIONS

Fixation of low-energy pelvic ring fractures in elderly is commonly performed after a period of conservative treatment, with persistent pain as the most frequent indication for fixation. Fracture classification based on stability seems to be of secondary importance. Timing for surgical fixation of the pelvic ring fracture in elderly patients remains diverse. Large well-designed comparative prospective studies and randomized controlled trials are needed to provide clearly substantiated guidelines.

Emergency Department Stress Radiographs of Lateral Compression Type-1 Pelvic Ring Injuries Are Safe, Effective, and Reliable

BACKGROUND

Occult instability of lateral compression type-1 (LC1) pelvic ring injuries may be determined with a fluoroscopic stress examination under anesthesia (EUA) performed in the operating room. We hypothesized that LC1 injuries, similar to some fractures of the extremities, could be radiographically stressed for stability in the emergency department (ED). Our primary objective was to determine if stress examination of LC1 fractures could be safely and accurately performed in the ED and could be tolerated by patients.

METHODS

A prospective, consecutive series of 70 patients with minimally displaced LC1 pelvic injuries (<10-mm displacement on presentation) underwent stress examinations performed by the on-call orthopaedic resident in the ED radiology suite. The stress examination series included static 40° inlet, internal rotation stress inlet, and external rotation stress inlet views. Pelvic fractures that had positive stress results (≥10 mm of overlap of the rami) were indicated for a surgical procedure. These fractures also underwent EUA in order for the 2 techniques to be compared.

RESULTS

All patients tolerated the ED stress examination without general anesthetic or hemodynamic instability. Fifty-seven patients (81%) had negative stress results and were allowed to bear weight. All patients with negative stress results who had 3-month follow-up went on to radiographic union without substantial displacement. For the patients with a positive stress result in the ED, the mean displacement was 15.15 mm (95% confidence interval [CI], 10.8 to 19.4 mm) for the ED stress test and 15.60 mm (95% CI, 11.7 to 19.4 mm) for the EUA (p = 0.86). Two patients with a negative ED stress test did not mobilize during their hospitalization and underwent EUA and conversion to a surgical procedure. Thus, a total of 11 patients underwent both stress testing in the ED and EUA; no patient had a positive result on one test but a negative result on the other.

CONCLUSIONS

ED stress examination of LC1 injuries is a safe and reliable method to determine pelvic ring stability. The displacement measured in the ED stress examination is similar to the displacement measured under general anesthesia. Furthermore, a negative ED stress examination predicts successful nonoperative treatment. Given the results of this study, we encourage the use of stress examination in the ED for LC1-type injuries involving complete sacral fractures only. Widescale adoption of this streamlined protocol may substantially diminish cost, anesthetic risk, and potential operations for patients.

LEVEL OF EVIDENCE

Diagnostic Level II. See Instructions for Authors for a complete description of levels of evidence.

Unstable minimally displaced lateral compression type 1 (LC1) pelvic ring injuries have a similar hospital course as intertrochanteric femur fractures

INTRODUCTION

The purpose of this study was to evaluate how the hospital course of minimally displaced LC1 fractures, with and without occult instability, compares with that of intertrochanteric femur fractures.

PATIENTS AND METHODS

Retrospective comparative cohort analysis at an urban level one trauma center of 40 consecutive patients with an isolated LC1 pelvic ring injury and 40 age/sex matched patients with an isolated intertrochanteric femur fracture was performed. Medical records and radiographs were reviewed for patient and injury characteristics, including demographics, displacement, time to surgery, ambulation, physical therapy (PT) clearance, hospital length of stay (LOS), and inpatient morphine milligram equivalents (MME).

RESULTS

The LC1 pelvic ring injury group included 26 (65%) patients with ≥ 10 mm of displacement on lateral stress radiographs. The unstable LC1 group, compared to the stable LC1 group, had a greater LOS (median difference (MD): 2 days, 95% confidence interval (CI): 1 to 4, p = 0.0004), longer time to ambulate 15 feet (MD: 1 day, CI: 1 to 2, p = 0.0002), longer time to clear PT (MD: 2 days, CI: 1 to 3, p = 0.0003), and more inpatient MMEs (MD: 386 MME, CI: 225.8 to 546.7, p = 0.0002). The unstable LC1 and intertrochanteric fracture groups had no detectable differences in LOS (p = 0.24), days to ambulate 15 feet (p = 0.46), days to clear PT (p = 0.95), and inpatient MMEs (p = 0.06).

CONCLUSION

Patients with minimally displaced unstable LC1 injuries had worse hospital courses than stable LC1 injuries and similar hospital courses as intertrochanteric femur fractures. These findings emphasize the associated morbidity of unstable LC1 injuries.

LEVEL OF EVIDENCE

Level III, Retrospective cohort study.

Sacral Fracture Completeness in Lateral Compression Type 1 Pelvic Ring Injuries Has Weak Interobserver Reliability

OBJECTIVES

To determine the agreement between fellowship-trained orthopaedic trauma surgeons in evaluating sacral fracture completeness in the setting of minimally displaced lateral compression type 1 pelvic ring injuries.

DESIGN

Survey study.

SETTING

Urban Level 1 trauma center.

PATIENTS/PARTICIPANTS

This study included 10 fellowship-trained orthopaedic trauma surgeons reviewing 10 cases of minimally displaced lateral compression type 1 injuries with proven occult instability (≥10 mm of fracture displacement on lateral stress radiographs). Sacral fractures were considered complete (n = 5; fracture line exiting posterior cortex of sacrum) or incomplete (n = 5).

INTERVENTION

Participants reviewed videos of all axial computed tomography images of the sacrum and were asked if the sacral fracture was complete or incomplete.

MAIN OUTCOME MEASUREMENTS

Interobserver reliability of completeness of sacral fracture.

RESULTS

Interobserver reliability among surgeons for completeness of sacral fractures was considered to be weak (k = 0.46) with a 95% confidence interval that ranged from minimal (k = 0.37) to weak (k = 0.55). None of the 5 unstable sacral fractures that were considered to be complete garnered 100% agreement among surgeons. Agreement for each of these cases ranged from 40% to 90%. In contrast, 4 of the 5 unstable sacral fractures considered to be incomplete had 100% agreement.

CONCLUSIONS

Completeness of sacral fractures had weak interobserver reliability among fellowship-trained orthopaedic trauma surgeons. Sacral fractures that were considered incomplete by all surgeons did have occult instability. These results highlight the large potential for error created by using sacral fracture completeness as a criterion to rule out occult instability.

LEVEL OF EVIDENCE

Diagnostic Level III. See Instructions for Authors for a complete description of levels of evidence.

Lateral compression type 1 (LC1) pelvic ring injuries: a spectrum of fracture types and treatment algorithms

Lateral compression type 1 (LC1) fractures are the commonest pelvic ring injury. However, they represent a heterogenous spectrum of injury mechanisms and fracture patterns, resulting in a lack of strong evidence for a universally agreed treatment algorithm. Although consensus exists that LC1 fractures have a preserved posterior ligamentous complex and are vertically stable, controversy persists around defining internal rotational instability. As such, treatment strategies extend from routine non-operative management through to dynamic imaging such as examination under anaesthetic (EUA) or stress radiographs to guide fixation algorithm. Multiple protocols sit between these two, all with slightly different thresholds for advocating surgery or otherwise, exemplifying a broad lack of consensus that is not seen for other, more severe, grades of pelvic ring injury. In the following review we discuss the evolving concepts of pelvic ring instability and management, starting from a historical perspective, through to current trends and controversies in LC1 fracture treatment. Emerging directions for research and emerging pharmacological and surgical treatments/technologies are also considered and expert commentary from 3 leading centres provided. The distinction is made between LC1 fracture arising from high-energy trauma and those following low-energy falls from standing height (so-called fragility fractures of the pelvis-FFP), since these two patient groups have different functional requirements and medical vulnerabilities. Issues pertaining to FFP are considered separately.

Cephalomedullary helical blade is independently associated with less collapse in intertrochanteric femur fractures than lag screws

OBJECTIVES

Excessive fracture site collapse and shortening in intertrochanteric femur fractures alter hip biomechanics and patient outcomes. The purpose of the study was to compare extent of collapse in cephalomedullary nails with blades or lag screws. We hypothesized that there would be no difference in collapse between helical blades and lag screws.

DESIGN

Retrospective cohort study.

SETTING

Single U.S. Level I Trauma Center.

PATIENTS

171 consecutive patients treated with cephalomedullary nails with either lag screw or blade for AO/OTA 31A1-3 proximal femur fractures and minimum 3-month follow-up.

INTERVENTION

Lag screw or helical blade in a cephalomedullary nail.

OUTCOME MEASURES

The primary outcome was fracture site collapse at 3 months.

RESULTS

There was a significantly higher proportion of reverse-oblique and transverse intertrochanteric femur fractures (31-A3) in the lag screw group (15/42 vs 25/129). A3 patterns were associated with more collapse. There was significantly less collapse in the blade group (median 4.7 mm, inter-quartile range 2.5-7.8 mm) than the screw group (median 8.4 mmm, inter-quartile range 3.7-11.2 mm, p 0.006). Median collapse was no different between blades and screws when comparing stable and unstable patterns. However, blades were independently associated with 2.5 mm less collapse (95%CI - 4.2, - 0.72 mm, p 0.006) and lower likelihood of excessive collapse (> 10 mm at 3 months, OR 0.3, 95% CI 0.13-0.74, p 0.007), regardless of fracture pattern.

CONCLUSIONS

Helical blades are independently associated with significantly less collapse than lag screws in intertrochanteric proximal femur fractures, after adjusting for unstable fracture patterns. In fracture patterns at risk for collapse, surgeons can consider use of a helical blade due to its favorable sliding properties compared to screws.

Mobilization versus displacement on lateral stress radiographs for determining operative fixation of minimally displaced lateral compression type I (LC1) pelvic ring injuries

PURPOSE

Operative fixation of minimally displaced lateral compression type I (LC1) pelvic ring injuries is considered by some if the patient is unable to mobilize or displacement is seen on stress radiographs. The purpose of this study was to compare these methods of determining operative fixation.

METHODS

A retrospective study of a prospectively gathered registry of LC1 injuries was performed before and after the adoption of a mobilization protocol. Fixation was considered if the patient was unable to mobilize 15 feet on the second day of admission. Prior to this protocol, all patients with displacement of ≥ 10 mm on stress radiographs were offered fixation. All patients received lateral stress radiographs (LSR), an anteroposterior pelvis radiograph in the lateral decubitus positions without sedation, to assess stability.

RESULTS

There were 21 and 18 patients treated under the stress radiograph and mobilization protocols. Displacement ≥ 10 mm was present in 12 (57%) and six (33%) patients in the LSR and mobilization groups. Under the mobilization protocol, patients with ≥ 10 mm of displacement on LSR all had incomplete sacral fractures and were less likely to mobilize (2 (33%) vs. 11 (92%); 95% confidence interval of the difference (CID) - 86 to - 9%). The mobilization protocol did not identify all cases of occult instability and resulted in an increased time to surgery compared to the LSR protocol (5 vs. 2 days, 95% CID 1 to 5).

CONCLUSION

Under the mobilization protocol, unstable LC1 injuries were less likely to mobilize and the time to surgery was increased.

Trochanteric fixation nail advanced with helical blade and cement augmentation: early experience with a retrospective cohort

Intra-articular screw cut-out is a potential complication of intertrochanteric femur fracture fixation with a cephalomedullary nail. Cement augmentation of fixation in the proximal segment offers the prospect of increased stability and fewer complications, but clinical experience with non-resorbable cement is limited. To determine the handling properties and efficacy of this new technique, we performed a retrospective propensity-matched cohort of forty-four geriatric intertrochanteric femur fractures treated with a cephalomedullary nail with (n = 11) or without (n = 33) augmentation with non-resorbable cement injected into the proximal segment. In the patients treated with cement augmentation, at minimum 3-month follow-up, there were no instances of intra-articular cut-out, and no increase in re-operation compared to conventional fixation. Cement augmentation appears to be safe and effective in geriatric intertrochanteric femur fractures to mitigate risk of cut-out.

Assessment of instability in type B pelvic ring fractures

Pelvic ring fractures have increased in incidence and operative fixation over the past several decades. These are dynamic injuries but decisions on operative management are still often made on the basis of static imaging. Expert opinion varies greatly on which injuries require fixation and how much fixation. Examination under anaesthesia has been shown to guide management of pelvic injuries by more accurately assessing levels of instability.