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

Patient Preferences for Operative Versus Nonoperative Treatment of LC1 Pelvis Fracture: A Discrete Choice Experiment

OBJECTIVES

To quantify how patients with lateral compression type 1 (LC1) pelvis fracture value attributes of operative versus nonoperative treatment.

METHODS

DESIGN

Discrete choice experiment.

SETTING

Three US Level 1 trauma centers.

PATIENT SELECTION CRITERIA

Adult survivors of an LC1 pelvis treated between June 2016 and March 2023 were identified from institutional registries. The choice experiment was administered as a survey from March through August 2023.

OUTCOME MEASURES AND COMPARISONS

Participants chose between 12 hypothetical comparisons of treatment attributes including operative or nonoperative care, risk of death, severity of pain, risk of secondary surgery, shorter hospital stay, discharge destination, and independence in ambulation within 1 month of injury. The marginal utility of each treatment attribute, for example, the strength of participants' aggregate preference for an attribute as indicated by their survey choices, was estimated by multinomial logit modeling with and without stratification by treatment received.

RESULTS

Four hundred forty-nine eligible patients were identified. The survey was distributed to 182 patients and collected from 72 patients (39%) at a median 2.3 years after injury. Respondents were 66% female with a median age of 59 years (IQR, 34-69 years). Before injury, 94% ambulated independently and 75% were working; 41% received operative treatment. Independence with ambulation provided the highest relative marginal utility (21%, P < 0.001), followed by discharge to home versus skilled nursing (20%, P < 0.001), moderate versus severe postdischarge pain (17%, P < 0.001), shorter hospital stay (16%, P < 0.001), secondary surgery (15%, P < 0.001), and mortality (10%, P = 0.02). Overall, no relative utility for operative versus nonoperative treatment was observed (2%, P = 0.54). However, respondents strongly preferred the treatment they received: operative patients valued operative treatment (utility, 0.37 vs. -0.37, P < 0.001); nonoperative patients valued nonoperative treatment (utility, 0.19 vs. -0.19, P < 0.001).

CONCLUSIONS

LC1 pelvis fracture patients valued independence with ambulation, shorter hospital stay, and avoiding secondary surgery and mortality in the month after their injury. Patients preferred the treatment they received rather than operative versus nonoperative care.

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.

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.

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.

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.