An alphanumeric classification of osteoporotic pelvic ring injuries

Biomechanical evaluation of an experimental internal ring fixator (RingFix) for stabilization of pelvic ring injuries on an osteoporotic bone model

During the last decades, effective pain reduction and early mobilization were identified as the central priorities in therapy of insufficiency fractures of the pelvis. For operative treatment minimally-invasive stabilization techniques are favored. While there is consensus on the significance of sufficient dorsal stabilization the role of additional fixation of the anterior fracture component stays under discussion. Within the present study we developed an internal ring fixator system (RingFix) with the question whether an in-itself-closed construct can improve stability of the entire ring structure. RingFix was evaluated on an osteoporotic bone model with a standardized FFP IIIc fracture within an established biomechanical setup regarding its primary stabilization potential. Further, it was compared to transiliac-transsacral screw fixation with and without stabilization of the anterior fracture component. The transiliac-transsacral fixation with separate screw fixation of the anterior fracture showed significantly higher stability than the RingFix and the transiliac-transsacral screw fixation without anterior stabilization. Our results show that stabilization of the anterior fracture component relevantly improves the stability of the entire ring construct. As a bridging stabilizer, RingFix shows biomechanical advantages over an isolated dorsal fracture fixation, but inferior results than direct stabilization of the single fracture components.

Acetabular fractures in geriatric patients: epidemiology, pathomechanism, classification and treatment options

The incidence of geriatric acetabular fractures has shown a sharp increase in the last decades. The majority of patients are male, which is different to other osteoporotic fractures. The typical pathomechanism generally differs from acetabular fractures in young patients regarding both the direction and the amount of force transmission to the acetabulum via the femoral head. Geriatric fractures very frequently involve anterior structures of the acetabulum, while the posterior wall is less frequently involved. The anterior column and posterior hemitransverse (ACPHT) fracture is the most common fracture type. Superomedial dome impactions (gull sign) are a frequent feature in geriatric acetabular fractures as well. Treatment options include nonoperative treatment, internal fixation and arthoplasty. Nonoperative treatment includes rapid mobilisation and full weighbearing under analgesia and is advisable in non- or minimally displaced fractures without subluxation of the hip joint and without positive gull sign. Open reduction and internal fixation of geriatric acetabular fractures leads to good or excellent results, if anatomic reduction is achieved intraoperatively and loss of reduction does not occur postoperatively. Primary arthroplasty of geriatric acetabular fractures is a treatment option, which does not require anatomic reduction, allows for immediate postoperative full weightbearing and obviates several complications, which are associated with internal fixation. The major issue is the fixation of the acetabular cup in the fractured bone. Primary cups, reinforcement rings or a combination of arthroplasty and internal fixation may be applied depending on the acetabular fracture type.

Do we need to fix the anterior fracture component in insufficiency fractures of the pelvis? A biomechanical comparison on an FFP type IIIc fracture in an osteoporotic pelvic bone model

There is a growing understanding of the specific characteristics of insufficiency fractures of the pelvis and of general requirements for the treatment of affected patients with focus on early mobilization and effective pain reduction as the main goals of therapy. While there is consensus on the significance of achieving stability of the dorsal pelvic ring structures there is still an open discussion about the potential benefits of additional stabilization of an anterior fracture component. Within a biomechanical test setup, two established methods of dorsal fracture fixation were tested under axial loading (25-1200 N; 1000 test cycles) on an explicit osteoporotic bone model (n = 32) with a standardized FFP type IIIc fracture with and without additional fixation of the anterior fracture component. Dorsal fixation was performed with and long and a short 7.3 mm cannulated screw in S1 in one group (n = 16), and a trans sacral bar with an additional short 7.3 mm cannulated screw in S1 in the other group (n = 16). Half of the samples received a 7.3 mm cannulated retrograde transpubic screw for anterior fixation. The fixation with the trans sacral bar and the additional anterior screw fixation showed the highest rate of stability (p = 0.0014), followed by the double SI-screw fixation with stabilization of the anterior fracture (p = 0.0002). During testing, we observed the occurrence of new sacral fractures contralateral to the initial fracture in 22/32 samples. The results let us assume that stabilization of an additional anterior fracture component relevantly improves the stability of the entire ring construct and might prevent failure of the dorsal stabilization or further fracture progression.

[Sacral H-shaped fractures between traumatic, insufficiency and fatigue fractures : Similarities, differences and controversies]

In the basic entirety of stress fractures, insufficiency fractures are defined as fractures caused by prolonged normal or physiological loading of a bone with insufficient elastic resistance. This clearly distinguishes it from fatigue fractures, in which excessive loads are continuously applied to a bone with normal elastic resistance. According to Pentecost (1964) both entities of stress fracture result from "the inherent inability of the bone to withstand stress applied without violence in a rhythmical, repeated, subthreshold manner". This distinguishes them from acute traumatic fractures. In the clinical routine these differences are not always so clearly presented. The example of the H‑shaped sacral fracture is used to illustrate the relevance of a clear terminology. In this context, current controversies in the treatment of sacral insufficiency fractures are discussed.

Internal fixation of radiation-induced fragility fractures of the pelvis: a case series

BACKGROUND

The optimal treatment for radiation-induced fragility fractures of the pelvis (RI-FFP) is not well evaluated due to the rarity of the condition.

PURPOSE

The aim of this retrospective study was to assess the prevalence of RI-FFP, the radiological and clinical outcomes as well as the complications of patients treated with internal fixation.

METHODS

A retrospective review of our database was performed to identify all surgically treated patients with RI-FFP. Surgical stabilization was recommended for patients with FFP type III and FFP type IV. Surgical stabilization was also recommended after 5-7 days for patients with FFP type II in case of unsuccessful conservative treatment. Demographic data, fracture patterns according to the FFP classification of Rommens and Hofmann, type of treatment and surgery-related complications including nonunion, hardware failure, fracture progression (secondary fracture) or infection were documented.

RESULTS

Among 500 patients with FFP, the prevalence of patients with RI-FFP was 1% (5/500): 5 patients with a median age of 79 years (76-79). The median time interval from radiation to fracture was 18 months (18-24). All of them underwent internal fixation. Two patients experienced surgery-related complications, one due to hardware failure and one due to fracture progression. At median follow-up of 27 months, all fractures had healed. Patients reached a good level of mobility with a median Parker Mobility Score of 7 and suffered moderate pain with a median value of 2.5 on the numeric rating scale.

CONCLUSION

RI-FFP remains a rare injury (1%). In our experience, patients, who underwent surgical treatment, obtained a high level of mobility and a moderate pain score after 2 years of follow-up. Internal fixation can be recommended in RI-FFP. Because bone healing may be impaired due to previous irradiation, highly stable constructs are required to avoid fracture progression or revision surgery.

LEVEL OF EVIDENCE

III, retrospective study.

Fragility Fractures of the Pelvis: Current Practices and Future Directions

PURPOSE OF REVIEW

To summarise the current evidence and clinical practices for patients with fragility fractures of the pelvis (FFP).

RECENT FINDINGS

FFPs are an increasingly prevalent and recognised problem in the elderly population. Recent evidence indicates they have a significant impact on function, morbidity and mortality. While traditional management of FFPs was predominantly non-surgical, surgical options have been increasingly used, with a range of surgical methods available. To date, limited consensus exists on the optimal strategy for suitable patient selection, and clinical trials in this population have proved problematic. The management of FFPs requires a multi-faceted approach to enhance patient care, including adequate pain control, minimisation of complications and optimisation of medical management. Early return to mobilisation should be a key treatment goal to maintain functional independence. The selection of patients who will maximally benefit from surgical treatment, and the most appropriate surgical strategy to employ, remains contentious.

The impact of specific fracture characteristics of low-energy fractures of the pelvis on mortality

Background

Pelvic fractures in older patients are associated with relevant morbidity and mortality. Both might be determined by fracture morphology and/or patient characteristics. The aim of this project is to investigate the prognostic value of specific fracture characteristics with respect to overall survival and to compare it with an established classification system.

Methods

Retrospective analysis of patients ≥ 60 years, treated conservatively for a CT-scan verified, low-energy pelvic ring fracture between August 2006 and December 2018. Survival data was available from patients’ charts and cantonal or national registries.

The prognostic value of fracture characteristic describing the anterior and posterior involvement of the pelvic ring was investigated. This analysis was repeated after patients were stratified into a high-risk vs a low-risk group according to patient characteristic (age, gender, comorbidities, mobility, living situation). This allowed to assess the impact of the different fracture morphologies on mortality in fit vs. frail senior patients separately.

Results

Overall, 428 patients (83.4% female) with a mean age of 83.7 years were included. Two thirds of patients were still living in their home and mobile without walking aid at baseline. In-hospital mortality was 0.7%, overall, one-year mortality 16.9%. An independent and significant association of age, gender and comorbidities to overall survival was found. Further, the occurrence of a horizontal sacral fracture as well as a ventral comminution or dislocation was associated with an increased mortality. The effect of a horizontal sacral fracture was more accentuated in low-risk patients while the ventral fracture components showed a larger effect on survival in high-risk patients.

Conclusion

Specific fracture characteristics may indicate a higher risk of mortality in conservatively treated patients with a low-energy pelvic ring fracture. Hence, they should be taken into account in future treatment algorithms and decisions on patient management.

Low interobserver and intraobserver reliability using the Matta radiographic system for intraoperative assessment of reduction following acetabular ORIF

INTRODUCTION

The system described by Matta for rating acetabular fracture quality of reduction following ORIF has been used extensively throughout the literature. However, the reliability of this system remains to be validated. We sought to determine the interobserver and intraobserver reliability of this system when used by fellowship-trained pelvic and acetabular surgeons to evaluate intraoperative fluoroscopy.

METHODS

This is a retrospective evaluation of a prospectively collected acetabular fracture database at an academic level I trauma center. The quality of reduction of all acetabular fractures treated with open reduction internal fixation (ORIF) between May 2013 and December 2015 was assessed using three standard intraoperative fluoroscopic views (anteroposterior and two 45˚ oblique Judets). Displacement of ≤1 mm was considered to be an anatomic reduction, 2-3 mm imperfect, and >3 mm poor according to the system described by Matta. A total of 107 acetabular fractures treated with ORIF with complete intraoperative fluoroscopic images during that time period were available for review. Acetabular fracture reductions were reviewed by the operative surgeon at the time of surgery and subsequently reviewed by two fellowship-trained pelvic and acetabular surgeons. All reduction assessments were performed in a blinded fashion. The primary outcome measure was interobserver reliability for assessing reduction quality. This was evaluated using a weighted kappa (κ_w) statistic between each evaluator and the operative surgeon and a generalized kappa (κ_g) for all 3 surgeons. After a 6-week "washout interval," the surgeons reviewed the images again and intraobserver agreement was calculated using a weighted kappa statistic.

RESULTS

Interobserver reliability based on the initial assessment was low (κ_g = 0.09); however, did slightly improve with the second assessment to fair (κ_g = 0.24). Intraobserver reliability ranged from slight (κ_w = 0.20) to moderate (κ_w = 0.53) among the surgeons.

DISCUSSION

Low interobserver and intraobserver reliability was found when quality of reduction was assessed with intraoperative fluoroscopic images by the operative and two other pelvic and acetabular surgeons using the Matta system. Given the importance of an anatomic reduction on functional and radiographic outcomes, an accurate and reliable system for assessing intraoperative quality of reduction is essential.

Focusing on individual morphological fracture characteristics of pelvic ring fractures in elderly patients can support clinical decision making

Introduction

Pelvic ring fractures in the elderly are often caused by minor trauma. Treatment of these patients is currently based on fracture classification, clinical course, and ability to mobilize. Our aim was to identify morphological fracture characteristics with potential prognostic relevance and evaluate their association with clinical decision making and outcome, as well as their interobserver reliability.

Methods

Five fracture characteristics were investigated as potential variables: 1. Extent of the dorsal pelvic ring fracture (absent, unilateral, bilateral); 2. Extent of the ventral pelvic ring fracture (absent, unilateral, bilateral); 3. Presence of a horizontal sacral fracture; 4. Ventral dislocation; 5. Ventral comminution.

These characteristics were assessed retrospectively in a series of 548 patients. The association of their presence with the decision to perform surgery, failure of conservative treatment and the length of hospital stay (LOS) was determined. Further, the inter-observer reliability for the specific characteristics was calculated and the relation with survival assessed.

Results

Four of the five evaluated characteristics showed an association with clinical decision making and patient management. In particular the extent of the dorsal fractures (absent vs. unilateral vs. bilateral) (OR = 7.0; p < 00.1) and the presence of ventral comminution/dislocation (OR = 2.4; p = 0.004) were independent factors for the decision to perform surgery. Both the extent of the dorsal fracture (OR = 1.8; p < 0.001) and the presence of ventral dislocation (OR = 1.7; p = 0.003) were independently associated with a prolonged overall LOS.

The inter-observer agreement for the fracture characteristics ranged from moderate to substantial.

A relevant association with increased mortality was shown for horizontal sacral and comminuted ventral fractures with hazard ratios (HR) of 1.7 (95% CI: 1.1, 2.5; p = 0.008) and HR = 1.5 (95% CI: 1.0, 2.2; p = 0.048).

Conclusion

In the elderly, the extent of the dorsal fractures and the presence of ventral comminution/dislocation were associated to the decision to undergo surgery, failure of conservative treatment and length of stay. Survival was related to horizontal sacral fractures and ventrally comminuted fractures. These characteristics thus represent a simplified but highly informative approach for the evaluation of pelvic ring fractures in the elderly. This approach can support clinical decision making, promote patient-centred treatment algorithms and thus improve the outcome of individualized care.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12877-022-03222-0.

OF-Pelvis classification of osteoporotic sacral and pelvic ring fractures

Objectives

Osteoporotic fractures of the pelvis (OFP) are an increasing issue in orthopedics. Current classification systems (CS) are mostly CT-based and complex and offer only moderate to substantial inter-rater reliability (interRR) and intra-rater reliability (intraRR). MRI is thus gaining importance as a complement.

This study aimed to develop a simple and reliable CT- and MRI-based CS for OFP.

Methods

A structured iterative procedure was conducted to reach a consensus among German-speaking spinal and pelvic trauma experts over 5 years. As a result, the proposed OF-Pelvis CS was developed. To assess its reliability, 28 experienced trauma and orthopedic surgeons categorized 25 anonymized cases using X-ray, CT, and MRI scans twice via online surveys. A period of 4 weeks separated the completion of the first from the second survey, and the cases were presented in an altered order. While 13 of the raters were also involved in developing the CS (developing raters (DR)), 15 user raters (UR) were not deeply involved in the development process.

To assess the interRR of the OF-Pelvis categories, Fleiss’ kappa (κ_F) was calculated for each survey. The intraRR for both surveys was calculated for each rater using Kendall’s tau (τ_K). The presence of a modifier was calculated with κ_F for interRR and Cohen’s kappa (κ_C) for intraRR.

Results

The OF-Pelvis consists of five subgroups and three modifiers. Instability increases from subgroups 1 (OF1) to 5 (OF5) and by a given modifier. The three modifiers can be assigned alone or in combination.

In both surveys, the interRR for subgroups was substantial: κ_F = 0.764 (Survey 1) and κ_F = 0.790 (Survey 2). The interRR of the DR and UR was nearly on par (κ_F Survey 1/Survey 2: DR 0.776/0.813; UR 0.748/0.766). The agreement for each of the five subgroups was also strong (κ_F min.–max. Survey 1/Survey 2: 0.708–0.827/0.747–0.852). The existence of at least one modifier was rated with substantial agreement (κ_F Survey 1/Survey 2: 0.646/0.629).

The intraRR for subgroups showed almost perfect agreement (τ_K = 0.894, DR: τ_K = 0.901, UR: τ_K = 0.889). The modifier had an intraRR of κ_C = 0.684 (DR: κ_C = 0.723, UR: κ_C = 0.651), which is also considered substantial.

Conclusion

The OF-Pelvis is a reliable tool to categorize OFP with substantial interRR and almost perfect intraRR. The similar reliabilities between experienced DRs and URs demonstrate that the training status of the user is not important. However, it may be a reliable basis for an indication of the treatment score.

The FFP-classification: From eminence to evidence

Fragility fractures of the pelvis (FFP) are a clinical entity with a rapidly growing incidence among elderly women. The characteristics of these fractures are different from those appearing after high-energy trauma. In 2013, the comprehensive FFP-classification provided a new framework for analysis of these fractures. It is based on the estimation of loss of stability in the pelvic ring. It is connected with recommendations for surgical treatment, justified by the fact that higher instabilities will need surgical stabilization. Since ist appearance, we can observe an increasing clinical-scientific interest in FFP. Multiple publications use the FFP-classification studying the characteristics of fractures, choice of treatment and outcome. Other studies focus on minimal-invasive techniques for stabilization. The actual knowledge describes higher mortality rates as the reference population, lower mortality rates after operative treatment but for the price of surgery-related complications. Mobility, independency and quality of life are worse than before the fracture, independent of the FFP-classification and the type of treatment. The classification triggered a rapid increase of expertise. This publication gives a detailed overview on the evolution from eminence to evidence.