Stability of internal versus external fixation in osteoporotic pelvic fractures - a biomechanical analysis

Anterior internal versus external fixation of unstable pelvis fractures was not associated with discharge destination, critical care, length of stay, or hospital charges

PURPOSE

Determine if anterior internal versus supra-acetabular external fixation of unstable pelvic fractures is associated with care needs or discharge.

METHODS

A retrospective cohort study was performed at two tertiary trauma referral centers. Adults with unstable pelvis fractures (AO/OTA 61B/61C) who received operative fixation of the anterior and posterior pelvic ring by two orthopedic trauma surgeons from October 2020 to November 2022 were included. The primary outcome was discharge destination. Secondary outcomes included intensive care unit (ICU) or ventilator days, length of stay, and hospital charges.

RESULTS

Eighty-three eligible patients were 38.6% female, with a mean age of 47.2 ± 20.3 years and BMI 28.1 ± 6.4 kg/m2. Fifty-nine patients (71.1%) received anterior pelvis internal fixation and 24 (28.9%) received external fixation. External fixation was associated with weight-bearing restrictions (91.7% versus 49.2%, p = 0.01). No differences in demographic, functional status, insurance type, fracture classification, or injury severity measures were observed by treatment. Internal versus external anterior pelvic fixation was not associated with discharge to home (49.2% versus 29.2%, p = 0.10), median ICU days (3.0 [interquartile range (IQR) 7.8 versus 5.5 [IQR 4.3], p = 0.14, ventilator days (0 [IQR 6.0] versus 0 [IQR 2.8], p = 0.51), length of stay (13.0 [IQR 13.0] versus 17.5 (IQR 20.5), p = 0.38), or total hospital charges (US dollars 180,311 [IQR 219,061.75] versus 243,622 [IQR 187,111], p = 0.14).

CONCLUSIONS

Anterior internal versus supra-acetabular external fixation of unstable pelvis fractures was not significantly associated with discharge destination, critical care, hospital length of stay, or hospital charges. This sample may be underpowered to detect differences between groups.

LEVEL OF EVIDENCE

Therapeutic Level IV.

Evaluating the stability of external fixators following pelvic injury: A systematic review of biomechanical testing methods

INTRODUCTION

This systematic review aims to identify previously used techniques in biomechanics to assess pelvic instability following pelvic injury, focusing on external fixation constructs.

METHODS

A systematic literature search was conducted to include biomechanical studies and to exclude clinical trials.

RESULTS

Of an initial 4666 studies found, 38 met the inclusion criteria. 84% of the included studies were retrieved from PubMed, Scopus, and Web of Science. The studies analysed 106 postmortem specimens, 154 synthetic bones, and 103 computational models. Most specimens were male (97% synthetic, 70% postmortem specimens). Both the type of injury and the classification system employed varied across studies. About 82% of the injuries assessed were of type C. Two different fixators were tested for FFPII and type A injury, five for type B injury, and fifteen for type C injury. Large variability was observed for external fixation constructs concerning device type and configuration, pin size, and geometry. Biomechanical studies deployed various methods to assess injury displacement, deformation, stiffness, and motion. Thereby, loading protocols differed and inconsistent definitions of failure were determined. Measurement techniques applied in biomechanical test setups included strain gauges, force transducers, and motion tracking techniques.

DISCUSSION AND CONCLUSION

An ideal fixation method should be safe, stable, non-obstructive, and have low complication rates. Although biomechanical testing should ensure that the load applied during testing is representative of a physiological load, a high degree of variability was found in the current literature in both the loading and measurement equipment. The lack of a standardised test design for fixation constructs in pelvic injuries across the studies challenges comparisons between them. When interpreting the results of biomechanical studies, it seems crucial to consider the limitations in cross-study comparability, with implications on their applicability to the clinical setting.

[Diagnostics and treatment of insufficiency fractures of the pelvis]

Insufficiency fractures of the pelvis have increased in recent years, primarily due to the demographic change and the incidence will continue to rise. In addition to conventional X‑rays, the diagnostics always require slice imaging. Unlike high-energy trauma magnetic resonance imaging (MRI) plays an important role in insufficiency fractures. Once the fracture has been diagnosed, in addition to the extent of instability in the anterior and posterior pelvic rings, the pain symptoms are crucial for the decision on surgical treatment. The basic principle is to stabilize as little as possible but as much as necessary. There are currently a variety of procedures that can be applied as a minimally invasive procedure, especially for the often slightly or displaced insufficiency fractures. The decisive factor for treatment is that it enables early mobilization of the patients. All of these measures must be accompanied by thorough diagnostics of osteoporosis and the appropriate treatment.

Clinical and epidemiological characteristics of 369 patients with pelvic fractures in Eastern Zhejiang Province of China: a retrospective study

BACKGROUND

Data on the epidemiological characteristics and prognostic factors of patients with pelvic fractures are lacking, particularly in China. This study aimed to summarise the clinical and epidemiological characteristics of patients with pelvic fractures in eastern Zhejiang Province, China, and to identify risk factors for poor prognosis.

METHODS

The clinical data of 369 patients with pelvic fractures admitted to the Ningbo No. 6 Hospital between September 2020 and September 2021 were retrospectively analysed. Data on the demographic characteristics; fracture classification; injury time, cause, and site; treatment plan; and prognosis were collected using the Picture Archiving and Communication System and the Hospital Information System. Differences in constituent proportions were analysed using the chi-square test. Logistic regression analysis was used to identify factors affecting patient prognosis. Statistical significance was set at p ≤ 0.05.

RESULTS

Among the 369 patients, there were 206 men and 163 women, at a ratio of 1.26:1, and the average age was 53.64 ± 0.78 years. More than 50% of patients were aged 41-65 years. The average length of hospital stay was 18.88 ± 1.78 days. The three most common causes of pelvic fractures were traffic accidents (51.2%), falls from height (31.44%), and flat-ground falls (14.09%). There were significant differences in the distribution of the three causes of injury depending on age (p < 0.001), sex (p < 0.001), and occupation (p < 0.0001). Most patients were manual workers (48.8%). Furthermore, most patients (n = 262, 71.0%) underwent surgical treatment for pelvic fractures. Postoperative complications occurred in 26 patients (7.05%), and infection was the main complication (73.08%). Age (p = 0.013), occupation (p = 0.034), cause of injury (p = 0.022), treatment options (p = 0.001), and complications (p < 0.0001) were independent factors affecting the prognosis of patients with pelvic fractures. One death (0.027%) occurred, which was due to severe blood loss.

CONCLUSIONS

Age, occupation, cause of injury, treatment options and complications were factors affecting patient prognosis. In addition, changes in blood flow and prevention of infection warrant attention.

Is cement-augmented sacroiliac screw fixation with partially threaded screws superior to that with fully threaded screws concerning compression and pull-out force in fragility fractures of the sacrum? - a biomechanical analysis

Background

Providing a stable osteosynthesis in fragility fractures of the pelvis can be challenging. Cement augmentation increases screw fixation in osteoporotic bone. Generating interfragmentary compression by using a lag screw also improves the stability. However, it is not known if interfragmentary compression can be achieved in osteoporotic sacral bone by cement augmentation of lag screws.

The purpose of this study was to compare cement-augmented sacroiliac screw osteosynthesis using partially versus fully threaded screws in osteoporotic hemipelvises concerning compression of fracture gap and pull-out force.

Methods

Nine fresh-frozen human cadaveric pelvises with osteoporosis were used. In all specimens, one side was treated with an augmented fully threaded screw (group A), and the other side with an augmented partially threaded screw (group B) after generating a vertical osteotomy on both sides of each sacrum. Afterwards, first a compression test with fracture gap measurement after tightening of the screws was performed, followed by an axial pull-out test measuring the maximum pull-out force of the screws.

Results

The fracture gap was significantly wider in group A (mean: 1.90 mm; SD: 1.64) than in group B (mean: 0.91 mm; SD: 1.03; p = 0.028).

Pull-out force was higher in group A (mean: 1696 N; SD: 1452) than in group B (mean: 1616 N; SD: 824), but this difference was not statistically significant (p = 0.767).

Conclusions

Cement augmentation of partially threaded screws in sacroiliac screw fixation allows narrowing of the fracture gap even in osteoporotic bone, while resistance against pull-out force is not significantly lower in partially threaded screws compared to fully threaded screws.

Which factors influence treatment decision in fragility fractures of the pelvis? - results of a prospective study

BACKGROUND

The aim of the present study was to describe specific characteristics of patients suffering from pelvic fragility fractures and evaluate factors that might influence treatment decisions which may optimize treatment pathways and patient mobility in the future.

METHODS

A prospective study with patients suffering from fractures of the pelvis and aged 60 years or above was performed between 2012 and 2016. Data acquisition took place at admission, every day during hospitalization and at discharge.

RESULTS

One hundred thirty-four patients (mean age of 79.93 (± 7.67) years), predominantly female (84%), were included. Eighty-six patients were treated non-operatively. Forty-eight patients underwent a surgical procedure. The main fracture types were B2 fractures (52.24%) and FFP IIb fractures (39.55%). At the time of discharge, pain level (NRS) could be significantly reduced (p <  0.001). Patients who underwent a surgical procedure had a significantly higher pain level on day three and four compared to the non-operative group (p = 0.032 and p = 0.023, respectively). Significant differences were found in the mobility level: patients treated operatively on day four or later were not able to stand or walk on day three as compared to non-operatively treated patients. Regarding B2 fractures, a significantly higher mobility level difference between time of admission and discharge was found in patients treated with a surgical procedure compared to patients treated non-operatively (p = 0.035).

CONCLUSIONS

Fracture type, mobility level and pain level influence the decision to proceed with surgical treatment. Especially patients suffering from B2 fractures benefitted in terms of mobility level at discharge when treated operatively.

LEVEL OF EVIDENCE

II.

Minimally invasive internal fixation for unstable pelvic ring fractures: a retrospective study of 27 cases

Background

This study aimed to evaluate the radiographic and clinical outcomes of anterior subcutaneous internal fixation (INFIX) with or without posterior fixation for the treatment of unstable pelvic fractures.

Methods

Intraoperative blood loss, operation time, and duration of hospital stay were recorded, and fracture union and postoperative complications were evaluated. The fracture reduction quality was evaluated using the Matta score, pelvic deformity index (PDI), and pubic symphyseal width (PSW). In addition, the functional recovery and general quality of life were evaluated using the Majeed score and the 12-Item Short-Form Survey (SF-12), respectively. Furthermore, sacral nerve injury was evaluated using the Gibbons classification.

Results

Twenty-seven patients (14 males and 13 females) with an average age of 37.4 years were followed up for a mean of 22 months. The average operation time, median intraoperative blood loss, and average duration of hospital stay were 129 ± 47 min, 100 mL, and 22 ± 13 days, respectively. All patients achieved bony union with an average union time of 13.3 weeks. Furthermore, the average PDI and PSW were 0.07 ± 0.04 vs. 0.04 ± 0.03 (P = 0.009) and 1.15 ± 1.36 vs. 0.54 ± 0.17 (P = 0.048) before and after the operation, respectively. In 78% of the patients, the Matta or Majeed scores were excellent or good. The SF-12 physical and mental health scores were 45.1 ± 10.2 and 53.2 ± 6.3, respectively. Furthermore, one superficial surgical site infection, one loosening of INFIX, one lateral femoral cutaneous nerve irritation, one femoral nerve injury, and two implant discomforts due to the bar were noted. Among five patients with sacral nerve injuries, four were asymptomatic, and one just had paresthesia at the last follow-up.

Conclusion

INFIX with or without sacroiliac screws can achieve satisfactory radiographic and functional outcomes in the treatment of unstable pelvic ring fractures.

Trial registration

ChiCTR2000038812. Registered 04 October 2020. Retrospectively registered.

A Novel Instant 3-Dimensional Printing System for Postoperative Fracture Patients: A Comparative Cohort Study

Background

Traditional plaster (TP) is a widely used auxiliary fixation (AF) approach for postoperative fracture patients. However, patient discomfort and inconvenience to clinicians has limited its application. We introduce a novel instant 3-dimensional printing appliance system (3D-AS) to address such issues.

Material/Methods

Twenty-seven postoperative fracture patients were divided randomly between a TP group and a 3D-AS group, and analyzed retrospectively. Radiographic images during follow-up were evaluated for fracture healing and fracture reduction quality. The range of motion (ROM) was recorded to assess motor performance. Patient pain was assessed using the Visual Analogue Scale (VAS). Complications were also compared between the 2 groups.

Results

The patients comprised 17 men and 10 women with ages ranging from 21 to 69 years (mean age: 47.35). All patients completed a follow-up visit (range: 14–19 months, mean: 13.59 months). Although no significant difference was found between general characteristics (P>0.05) and the time of fracture union (P>0.05), significant differences between groups were seen in complications (P<0.05), VAS (P<0.01), patient satisfaction (P<0.05), and ROM for the upper joints (P<0.05).

Conclusions

Our study suggests that 3D-AS provides better upper-limb ROM and more comfortable healing for postoperative fracture patients, indicating that it can be recommended for use in such patients.