Reliability of RUST and modified RUST scores for evaluation of union in pediatric and adult femoral shaft fractures

Improvements in Pediatric Bone Loss Reconstruction With the Induced Membrane Technique

BACKGROUND

The induced membrane technique is now widely used for pediatric diaphyseal bone loss due to various etiologies. Although consolidation rates remain satisfactory, complications, and healing delays may occur requiring additional procedures. We studied a series of induced membrane bone reconstructions in which the second stage included an embedded endomembranous non vascularized fibular shaft, in addition to iliac bone grafts. The purpose of this study was to analyze the results in terms of bone consolidation and complications.

METHODS

This is a retrospective comparative and multicentric study of 32 children with large bone loss treated with the induced membrane reconstruction technique. Patients were divided into 2 groups according to the graft used during the second stage. The first group (G1) of 16 patients had a nonvascularized fibula embedded inside the membrane in addition with the corticocancellous grafts from the iliac crest. The second group (G2) of 16 patients underwent reconstruction using the original technique, with iliac crest graft only.

RESULTS

The 2 groups were similar in terms of etiologies of bone loss and follow-up (mean: 44 mo for G1 and 49 mo for G2). Mean bone losses were 15.4 cm (range: 2 to 25; SD: 5.6) for G1 and 10.6 cm (range: 3 to 19; SD: 5.2) for G2. In the first group, all patients healed primarily, with a mean time of 5.9 months (range: 4 to 8; SD: 1.6). In the second group, 2 of 16 patients did not healed; for the others 14, healing mean time was 6.9 months (range: 3 to 12; SD: 2.7). The short-term and long-term complications rates were 38% to 19% for G1 and 50% to 31% for G2, respectively. Regarding the donor site, the fibulas reconstructed spontaneously with a mean time of 4.8 months (range: 3 to 6; SD: 1.2).

CONCLUSIONS

The integration of a nonvascularized fibula during the second stage of the induced membrane technique appears to improve the consolidation rate in the pediatric population.

LEVEL OF EVIDENCE

Level III-Retrospective comparative study.

Patient-Reported Outcome Measurement Information Systems Physical Function and Pain Interference Scores Are Correlated With Tibial Shaft Fracture Nonunion Following Intramedullary Nailing

OBJECTIVES

To assess trends in Patient-Reported Outcome Measurement Information Systems (PROMIS) Physical Function (PF) and Pain Interference (PI) in surgically treated tibial shaft fracture patients progressing to union versus nonunion.

METHODS

DESIGN

Retrospective cohort study.

SETTING

Level 1 trauma center.

PATIENT SELECTION CRITERIA

Patients with operatively treated tibial shaft fractures (AO/OTA 42-A, B, C) using an intramedullary nail.

OUTCOME MEASURES AND COMPARISONS

PROMIS PF and PI were compared between patients progressing to union and patients requiring nonunion repair.

RESULTS

A total of 234 patients (196 union, 38 nonunion) were included consisting 144 men and 90 women. The mean age of included patients was 40.8 years. A significant difference in mean PROMIS PF between union and nonunion patients was observed at 1-3 months ( P = 0.005), 3-6 months ( P < 0.001), 6-9 months ( P = 0.003), and 6-12 months ( P = 0.018). The odds of developing nonunion for every unit decrease in PROMIS PF was significant at 3-6 months (OR 1.07, P = 0.028) and 6-9 months (OR 1.17, P = 0.015). A significant difference in mean PROMIS PI between union and nonunion patients was observed at 1-3 months ( P = 0.001), 3-6 months ( P = 0.005), and 6-9 months ( P = 0.005). The odds of developing nonunion for every unit increase in PROMIS PI was significant at 1-3 months (OR 1.11, P = 0.005), 3-6 months (OR 1.10, P = 0.011), and 6-9 months (OR 1.23, P = 0.011).

CONCLUSIONS

Poorly trending PROMIS PF and PI in the clinical setting is a factor that can be used to evaluate progression to nonunion following tibial shaft repair where imaging studies may lag behind.

LEVEL OF EVIDENCE

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

In Vivo Investigation of 3D-Printed Calcium Magnesium Phosphate Wedges in Partial Load Defects

Bone substitutes are ideally biocompatible, osteoconductive, degradable and defect-specific and provide mechanical stability. Magnesium phosphate cements (MPCs) offer high initial stability and faster degradation compared to the well-researched calcium phosphate cements (CPCs). Calcium magnesium phosphate cements (CMPCs) should combine the properties of both and have so far shown promising results. The present study aimed to investigate and compare the degradation and osseointegration behavior of 3D powder-printed wedges of CMPC and MPC in vivo. The wedges were post-treated with phosphoric acid (CMPC) and diammonium hydrogen phosphate (MPC) and implanted in a partially loaded defect model in the proximal rabbit tibia. The evaluation included clinical, in vivo µ-CT and X-ray examinations, histology, energy dispersive X-ray analysis (EDX) and scanning electron microscopy (SEM) for up to 30 weeks. SEM analysis revealed a zone of unreacted material in the MPC, indicating the need to optimize the manufacturing and post-treatment process. However, all materials showed excellent biocompatibility and mechanical stability. After 24 weeks, they were almost completely degraded. The slower degradation rate of the CMPC corresponded more favorably to the bone growth rate compared to the MPC. Due to the promising results of the CMPC in this study, it should be further investigated, for example in defect models with higher load.

Radiographic outcomes and non-union factor analysis in fragmentary segmental femoral shaft fractures (AO/OTA 32C3) treated with reamed antegrade nailing

This study retrospectively assessed radiographic outcomes and risk factors associated with non-union in femoral shaft fragmentary segmental fractures (AO/OTA 32C3) treated with reamed antegrade intra-medullary nailing. Radiological outcomes, including union and alignment, were evaluated. The risk factors for non-union were investigated, including demographics and treatment-related characteristics, such as the number of interlocking screws, segmentation length, main third fragment length, distance of the main third fragment, width ratio and exposed nail length in one cortex from immediate post-operative radiographs. Multivariate logistic regression was used for statistical analysis. Among 2295 femoral shaft fracture patients from three level-1 trauma centers, 51 met the inclusion criteria. The radiological union was achieved in 37 patients (73%) with a mean union time of 10.7 ± 4.8 months. The acceptable axial alignment was observed in 30 patients (59%). Multiple logistic regression analysis identified only exposed nail length as a significant risk factor for non-union (odds ratio: 1.599, p = 0.003) and the cut-off value was 19.1 mm (sensitivity, 0.786; specificity, 0.811). The study revealed high rates of non-union (27%) and malalignment (41%). Therefore, patients who underwent intramedullary nailing with an exposed nail length greater than 19.1 mm or about twice the nail diameter should be cautioned of the potential non-union.

Plate augmentation and hybrid bone grafting are effective treatments for atrophic nonunion of the femur with the original intramedullary nail retained in situ

The purpose of this study is to evaluate the efficacy of plate augmentation and hybrid bone grafting for treating atrophic nonunion of the femur with original intramedullary nail retained in situ.In this study, 36 patients with atrophic nonunion of the femur who underwent surgery using the technique of plate augmentation and a hybrid bone grafting while retaining the original intramedullary nail in situ in Xi'an Honghui Hospital from January 2019 to December 2021 were enrolled. 28 patients who met the inclusion and exclusion criteria were ultimately included in the study. These 28 patients, consisting of 20 males and 8 females with a mean age of 38 years, were evaluated based on factors such as operation time, intraoperative blood loss, the average hospitalization days. Additionally, the results and function of these patients were evaluated by union time, Wu's scores of limb function and incidence of serious complications.All 28 patients achieved bone union at the 12 month follow-up, with an average follow-up time of 14.6 ± 4.2 months.The average operation time was 68.3 ± 11.2 min, and the average intraoperative blood loss was 140 ± 22.6 ml. Patients were hospitalized for an average of 5.8 ± 1.1 days. Full clinical and radiological bone union was achieved on average at 5.1 ± 1.9 months. The mean value of Wu's scores at the 12 month follow-up was significantly higher than before the operation. Limb function was excellent in 27 patients and good in one patient at the 12 month follow-up. However, five patients experienced the lower limb vein thrombosis, including one deep vein thrombosis and four lower limb intermuscular vein thromboses. One patient had a superficial infections of the surgical incision site, while three patients reported pain and numbness where their iliac bone graft was extracted at the 12 month follow-up. The technique of plate augmentation and hybrid bone grafting, combined with retaining the original intramedullary nail in situ has been shown to be a safe, effective, simply and standardizable practice for treating atrophic femoral nonunion with an intact original IMN fixation.

Computer-Based Mechanobiological Fracture Healing Model Predicts Non-Union of Surgically Treated Diaphyseal Femur Fractures

As non-unions are still common, a predictive assessment of healing complications could enable immediate intervention before negative impacts for the patient occur. The aim of this pilot study was to predict consolidation with the help of a numerical simulation model. A total of 32 simulations of patients with closed diaphyseal femoral shaft fractures treated by intramedullary nailing (PFNA long, FRN, LFN, and DePuy Synthes) were performed by creating 3D volume models based on biplanar postoperative radiographs. An established fracture healing model, which describes the changes in tissue distribution at the fracture site, was used to predict the individual healing process based on the surgical treatment performed and full weight bearing. The assumed consolidation as well as the bridging dates were retrospectively correlated with the clinical and radiological healing processes. The simulation correctly predicted 23 uncomplicated healing fractures. Three patients showed healing potential according to the simulation, but clinically turned out to be non-unions. Four out of six non-unions were correctly detected as non-unions by the simulation, and two simulations were wrongfully diagnosed as non-unions. Further adjustments of the simulation algorithm for human fracture healing and a larger cohort are necessary. However, these first results show a promising approach towards an individualized prognosis of fracture healing based on biomechanical factors.

Clinical Assessments of Fracture Healing and Basic Science Correlates: Is There Room for Convergence?

PURPOSE OF REVIEW

The purpose of this review is to summarize the clinical and basic science methods used to assess fracture healing and propose a framework to improve the translational possibilities.

RECENT FINDINGS

Mainstays of fracture healing assessment include clinical examination, various imaging modalities, and assessment of function. Pre-clinical studies have yielded insight into biomechanical progression as well as the genetic, molecular, and cellular processes of fracture healing. Efforts are emerging to identify early markers to predict impaired healing and possibly early intervention to alter these processes. Despite of the differences in clinical and preclinical research, opportunities exist to unify and improve the translational efforts between these arenas to develop and optimize our ability to assess and predict fracture healing, thereby improving the clinical care of these patients.

The technique of "autologous bone grafting through channels" combined with double-plate fixation is effective treatment of femoral nonunion

PURPOSE

The aims of this retrospective study were to evaluate the effective treatment of femoral nonunion using the technique of "autologous bone grafting through channels" combined with double-plate fixation.

METHODS

In this study, 186 patients with nonunion fracture of femur who underwent surgery using the technique of "autologous bone grafting through channels" combined with double-plate fixation in Hong Hui Hospital from May 2010 to July 2020 were enrolled. Totally, 122 males and 64 females with mean age of 44 years were evaluated. These patients were evaluated for the full clinical and radiological union time, duration of follow-up, levels of post-operative limb shortening, and range of motion of adjacent joints, and incidence of serious complications.

RESULTS

The mean follow-up time was 22 ± 6.2 months (range 12-44 months). Mean union time from surgery using our technique to full clinical and radiological union was 7.6 ± 1.2 months (range 4-9 months). All patients have achieved the union after one operation or two operations using the technique. The one-operation union rate is 98.4%. Post-operative severe complications were seen in seven patients which included deep vein thrombosis; the surgical site infection and the fracture nonunion. The range of motion in the adjacent joint of 17.7% (33/186) in all patients have an effect to the limb function. Six patients have the limb shortening more than 10 mm after surgery.

CONCLUSION

The technique of "autologous bone grafting through channels" combined with double-plate fixation is showed to be safe, effective, and easy to master and operate surgical option for treating the femoral nonunion.

Effect of the degree of displacement of the third fragment on healing of femoral shaft fracture treated by intramedullary nailing

Objective

To investigate the effect of the degree of displacement of a femoral shaft fracture with the third fragment on fracture healing after intramedullary nailing.

Methods

In total, 216 patients with closed comminuted femoral fracture admitted to Lianyungang Hospital affiliated to Xuzhou Medical University from February 2010 to February 2016 were analyzed retrospectively. Among these patients, 142 were males and 74 were females, the mean age was 38 years (range 17–64 years), and 95 cases were on the right, while 121 cases were on the left. All patients were treated with a femoral interlocking intramedullary nail. Referring to the femoral shaft diameter, the degree of displacement of the third fragment was classified into four grades: grade I (displacement was less than a third of the diameter of the shaft): 121 cases; grade II (greater than a third of the diameter and less than two thirds): 52 cases; grade III (greater than two thirds of the diameter): 28 cases; and grade IV (fracture fragment turnover): 15 cases. According to the modified Radiological Union Scale for Femur (mRUSF), the fracture union rate and the mean union time of the fracture, the effect of the degree of displacement of the third fragment on fracture healing was evaluated.

Results

In total, 216 patients with a mean follow-up of 15.9 months (range 6–31 months) met the inclusion criteria. The best fracture healing was the grade I displacement, with a union rate of 89.2% and a mean union time of 7.7 months. The poorest fracture healing was for the grade IV displacement, with a union rate of 13.3% and a mean union time of 16.5 months. The healing was moderate in the grade II and III displacements, with a union rate of 46.2% and 28.6%, respectively, and a mean union time of 8.6 months and 13.5 months, respectively (P < 0.05).

Conclusions

The third fragment with grade I displacement requires no intervention, whereas fractures with grade IV displacement should be reduced to as near as possible to the diaphyseal bone defect to avoid nonunion. The third fragments with the grade II or III displacement should be treated with closed reduction whenever possible to achieve a displacement within the range of grade I to minimize the incidence of nonunion.

Validation of the modified radiographic union score for tibia fractures (mRUST) in murine femoral fractures

Bony union is a primary predictor of outcome after surgical fixation of long bone fractures. Murine models offer many advantages in assessing bony healing due to their low costs and small size. However, current fracture recovery investigations in mice frequently rely on animal sacrifice and costly analyses. The modified Radiographic Union Score for Tibia fractures (mRUST) scoring system is a validated metric for evaluating bony healing in humans utilizing plain radiographs, which are relatively inexpensive and do not require animal sacrifice. However, its use has not been well established in murine models. The aim of this study was to characterize the longitudinal course of mRUST and compare mRUST to other conventional murine fracture analyses. 158 mice underwent surgically created midshaft femur fractures. Mice were evaluated after fracture creation and at 7, 10, 14, 17, 21, 24, 28, 35, and 42 days post-injury. mRUST scoring of plain radiographs was performed by three orthopaedic surgeons in a randomized, blinded fashion. Interrater correlations were calculated. Micro-computed tomography (μCT) was analyzed for tissue mineral density (TMD), total callus volume (TV), bone volume (BV), trabecular thickness, trabecular number, and trabecular separation. Histomorphometry measures of total callus area, cartilage area, fibrous tissue area, and bone area were performed in a blinded fashion. Ultimate torque, stiffness, toughness, and twist to failure were calculated from torque-twist curves. A sigmoidal log-logistic curve fit was generated for mRUST scores over time which shows mRUST scores of 4 to 6 at 7 days post-injury that improve to plateaus of 14 to 16 by 24 days post-injury. mRUST interrater correlations at each timepoint ranged from 0.51 to 0.86, indicating substantial agreement. mRUST scores correlated well with biomechanical, histomorphometry, and μCT parameters, such as ultimate torque (r=0.46, p<0.0001), manual stiffness (r=0.51, p<0.0001), bone percentage based on histomorphometry (r=0.86, p<0.0001), cartilage percentage (r=-0.87, p<0.0001), tissue mineral density (r=0.83, p<0.0001), BV/TV based on μCT (r=0.65, p<0.0001), and trabecular thickness (r=0.78, p<0.0001), among others. These data demonstrate that mRUST is reliable, trends temporally, and correlates to standard measures of murine fracture healing. Compared to other measures, mRUST is more cost-effective and non-terminal. The mRUST log-logistic curve could be used to characterize differences in fracture healing trajectory between experimental groups, enabling high-throughput analysis.

Radiographic union score for tibia (RUST) scoring system in adult diaphyseal femoral fractures treated with intramedullary nailing: an assessment of interobserver and intraobserver reliability

OBJECTIVES

The Radiographic Union Score for Tibia (RUST) scoring system has been validated in multiple studies assessing the healing of tibial fractures. Our objective was to assess the interobserver and intraobserver reliability for the RUST in diaphyseal femoral fractures treated with intramedullary (IM) nailing.

PATIENTS AND METHODS

A total of 60 sets of anteroposterior (AP) and lateral radiographs of diaphyseal femoral fractures treated by reamed IM nailing were randomly selected from a prospectively collected database. The 60 sets of radiographs were then scored by three reviewers using the RUST system. Interobserver reliability was measured at initial scoring. The 60 sets of radiographs were scored again by the three reviewers to calculate the intraobserver reliability.

RESULTS

The RUST scores ranged from 4 to 12 with a mean score of 11.3 ± 1.3. The interobserver intraclass correlation coefficient (ICC) was 0.87 (95% CI, 0.81-0.92) and the intraobserver ICC was 0.91 (95% CI, 0.88-0.94), which indicated excellent agreement.

CONCLUSION

This study demonstrated that the RUST system can be used reliably in the assessment of healing in diaphyseal femur fractures treated by reamed intramedullary nailing, with excellent interobserver and intraobserver reliability.