Will My Tibial Fracture Heal? Predicting Nonunion at the Time of Definitive Fixation Based on Commonly Available Variables

Nonunion Fractures: Trends in Epidemiology and Treatment of Femur Fractures, 2017-2022

BACKGROUND

The incidence of femur fractures has increased in recent years, along with the rate of surgery and subsequent nonunion following these fractures. Nonunion is a significant concern due to the burden it places on both patients and the healthcare system. This study aims to investigate the demographic factors associated with femoral shaft fracture nonunion by comparing two surgical management approaches: open reduction internal fixation (ORIF) with plating versus closed reduction and fixation using intramedullary nailing (IMN).

METHODS

The TriNetX database was queried using current procedural terminology (CPT) codes for surgical repair of femoral shaft fractures (FSFs), including IMN surgery (CPT: 27506) and femur ORIF (CPT: 27507). The subsequent chronological nonunion cases were identified using the 10th revision of the International Classification of Diseases (ICD-10) codes for femoral nonunion (S72.301K, S72.302K). Results were analyzed both descriptively and comparatively to assess differences among patients. Factors considered included age, sex, ethnicity, race, smoking status, and the type of surgical management (ORIF versus nailing) across the six-year study period.

RESULTS

From 2017 to 2022, the prevalence of femoral shaft fracture surgeries increased for both IMN and ORIF. The rate of nonunion was 2.1% following IMN and 1.7% following ORIF. The mean age for nonunion was 54 years (SD: 20) following IMN and 63 years (SD: 18) following ORIF. Patients with a positive smoking history had higher rates of nonunion compared to those without.

CONCLUSION

Our study revealed a relatively consistent rate of FSFs and nonunion over the six-year period. However, with a growing population, the absolute number of cases is steadily increasing, underscoring the burden on the healthcare system. This study contributes to the growing body of literature focused on improving patient outcomes and promoting health equity in fracture management practices.

A Scoring System for Predicting Nonunion After Intramedullary Nailing of Femoral Shaft Fractures

INTRODUCTION

Femoral shaft nonunion negatively affects patient quality of life. Although multiple risk factors have been identified for femoral shaft nonunion after intramedullary nail (IMN) fixation, there is no quantitative model for predicting nonunion.

STUDY DESCRIPTION

The study is a retrospective cohort study of patients with femoral shaft fractures treated at two level one trauma centers who were followed to fracture union or nonunion. Patient, injury, and surgical characteristics were analyzed to create a quantitative model for nonunion risk after intramedullary nailing.

METHODS

Eight hundred one patients aged 18 years and older with femoral shaft fractures treated with reamed, locked IMNs were identified. Risk factors including demographics, comorbidities, surgical variables, and injury-related characteristics were evaluated. Multivariate analysis was conducted, and several variables were included in a scoring system to predict nonunion risk.

RESULTS

The overall nonunion rate was 7.62% (61/801). Multivariate analysis showed significant association among pulmonary injury (odds ratio [OR] = 2.19, P = 0.022), open fracture (OR=2.36, P = 0.02), current smoking (OR=3.05, P < 0.001), postoperative infection (OR=12.1, P = 0.007), AO/OTA fracture pattern type A or B (OR=0.43, P = 0.014), and percent cortical contact obtained intraoperatively ≥25% (OR=0.41, P = 0.021) and nonunion. The scoring system created to quantitatively stratify nonunion risk showed that a score of 3 or more yielded an OR of 6.38 for nonunion (c-statistic = 0.693, P < 0.0001).

CONCLUSIONS

Femoral shaft nonunion risk is quantifiable based on several independent injury, patient, and surgical factors. This scoring system is an additional tool for clinical decision making when caring for patients with femoral shaft fractures treated with IMNs.

Impact of osteoporosis and osteoporosis medications on fracture healing: a narrative review

Antiresorptive medications do not negatively affect fracture healing in humans. Teriparatide may decrease time to fracture healing. Romosozumab has not shown a beneficial effect on human fracture healing.

BACKGROUND

Fracture healing is a complex process. Uncertainty exists over the influence of osteoporosis and the medications used to treat it on fracture healing.

METHODS

Narrative review authored by the members of the Fracture Working Group of the Committee of Scientific Advisors of the International Osteoporosis Foundation (IOF), on behalf of the IOF and the Société Internationale de Chirurgie Orthopédique et de Traumatologie (SICOT).

RESULTS

Fracture healing is a multistep process. Most fractures heal through a combination of intramembranous and endochondral ossification. Radiographic imaging is important for evaluating fracture healing and for detecting delayed or non-union. The presence of callus formation, bridging trabeculae, and a decrease in the size of the fracture line over time are indicative of healing. Imaging must be combined with clinical parameters and patient-reported outcomes. Animal data support a negative effect of osteoporosis on fracture healing; however, clinical data do not appear to corroborate with this. Evidence does not support a delay in the initiation of antiresorptive therapy following acute fragility fractures. There is no reason for suspension of osteoporosis medication at the time of fracture if the person is already on treatment. Teriparatide treatment may shorten fracture healing time at certain sites such as distal radius; however, it does not prevent non-union or influence union rate. The positive effect on fracture healing that romosozumab has demonstrated in animals has not been observed in humans.

CONCLUSION

Overall, there appears to be no deleterious effect of osteoporosis medications on fracture healing. The benefit of treating osteoporosis and the urgent necessity to mitigate imminent refracture risk after a fracture should be given prime consideration. It is imperative that new radiological and biological markers of fracture healing be identified. It is also important to synthesize clinical and basic science methodologies to assess fracture healing, so that a convergence of the two frameworks can be achieved.

Case Studies of a Simulation Workflow to Improve Bone Healing Assessment in Impending Non-Unions

Background: The healing potential of a fracture is determined by mechanical and biological factors. Simulation-based workflows can help assess these factors to assist in predicting non-unions. The aim of this study was the introduction of two use cases for a novel patient-specific simulation workflow based on clinically available information. Methods: The used software is an extension of the "Ulm Bone Healing model" and was applied in two cases with non-union development after fracture fixation to show its principal feasibility. The clinical and radiographic information, starting from initial treatment, were used to feed the simulation process. Results: The simulation predicted non-union development and axial deviation in a mechanically driven non-union. In the case of a biological non-union, a slow, incomplete healing course was correctly identified. However, the time offset in callus bridging was discordant between the simulation and the distinctly slower healing response in the clinical case. Conclusions: The simulation workflow presented in the two clinical use cases allowed for the identification of fractures at risk for impending non-union immediately after the initial fixation based on available clinical and radiographic information. Further validation in a large non-union cohort is needed to increase the model's precision, especially in biologically challenging cases, and show its validity as a screening instrument.

Computational models of bone fracture healing and applications: a review

Fracture healing is a very complex physiological process involving multiple events at different temporal and spatial scales, such as cell migration and tissue differentiation, in which mechanical stimuli and biochemical factors assume key roles. With the continuous improvement of computer technology in recent years, computer models have provided excellent solutions for studying the complex process of bone healing. These models not only provide profound insights into the mechanisms of fracture healing, but also have important implications for clinical treatment strategies. In this review, we first provide an overview of research in the field of computational models of fracture healing based on CiteSpace software, followed by a summary of recent advances, and a discussion of the limitations of these models and future directions for improvement. Finally, we provide a systematic summary of the application of computational models of fracture healing in three areas: bone tissue engineering, fixator optimization and clinical treatment strategies. The application of computational models of bone healing in clinical treatment is immature, but an inevitable trend, and as these models become more refined, their role in guiding clinical treatment will become more prominent.

RISK FACTORS AT NON-UNION OF TIBIAL FRACTURE TREATED WITH INTRAMEDULLARY NAIL

Objective

Identify the predictors associated with delayed union at 6 months and non-union at 12 months in tibial shaft fractures treated with intramedullary nailing (IMN).

Methods

This retrospective longitudinal study included a cohort of 218 patients who sustained tibial shaft fractures and received IMN between January 2015 and March 2022. We gathered data on a range of risk factors, including patient demographics, trauma intensity, associated injuries, fracture characteristics, soft tissue injuries, comorbidities, addictions, and treatment-specific factors. We employed logistic bivariate regression analysis to explore the factors predictive of delayed union and non-union.

Results

At the 6-month follow-up, the incidence of delayed union was 28.9%. Predictors for delayed union included flap coverage, high-energy trauma, open fractures, the use of external fixation as a staged treatment, the percentage of cortical contact in simple type fractures, RUST score, and postoperative infection. After 12 months, the non-union rate was 15.6%.

Conclusion

the main predictors for non-union after IMN of tibial shaft fractures are related to the trauma energy. Furthermore, the initial treatment involving external fixation and postoperative infection also correlated with non-union. Level of Evidence III; Retrospective Longitudinal Study.

Three predictive scores compared in a retrospective multicenter study of nonunion tibial shaft fracture

BACKGROUND

Delayed union, malunion, and nonunion are serious complications in the healing of fractures. Predicting the risk of nonunion before or after surgery is challenging.

AIM

To compare the most prevalent predictive scores of nonunion used in clinical practice to determine the most accurate score for predicting nonunion.

METHODS

We collected data from patients with tibial shaft fractures undergoing surgery from January 2016 to December 2020 in three different trauma hospitals. In this retrospective multicenter study, we considered only fractures treated with intramedullary nailing. We calculated the tibia FRACTure prediction healING days (FRACTING) score, Nonunion Risk Determination score, and Leeds-Genoa Nonunion Index (LEG-NUI) score at the time of definitive fixation.

RESULTS

Of the 130 patients enrolled, 89 (68.4%) healed within 9 months and were classified as union. The remaining patients (n = 41, 31.5%) healed after more than 9 months or underwent other surgical procedures and were classified as nonunion. After calculation of the three scores, LEG-NUI and FRACTING were the most accurate at predicting healing.

CONCLUSION

LEG-NUI and FRACTING showed the best performances by accurately predicting union and nonunion.

Comparison of Radiographic Outcomes Assessed via the Radiographic Union Scale for Tibial Fractures and Alkaline Phosphatase Levels during the Tibial Healing Process: A Series of Case Reports

BACKGROUND/OBJECTIVES

Tibial diaphysis fractures are common injuries resulting from high-to-low-energy traumas in patients of all age groups, but few reports currently provide complementary parameters for the assessment of bone healing processes in the postoperative period. Serum alkaline phosphatase (ALP) and the scores from the Radiographic Union Scale for Tibial Fractures (RUST) can promote new horizons in this context. Therefore, the aim of this study was to assess the behavior of ALP and RUST through within-subject comparisons from immediately post-surgery to 49 days after tibial diaphysis fracture repair.

METHODS

This article included four case studies where patients underwent the same procedures. Adults of both sexes aged 18 to 60 years with tibial fractures requiring surgery were included. After surgical intervention (T1), the patients were followed for 49 days after surgery, returning for follow-up appointments on the 21st (T2) and 49th (T3) days. At the follow-up appointments, new X-ray images were obtained, and blood samples were collected for ALP measurement.

RESULTS

Serum ALP levels increased by T2 following tibial reamed intramedullary nailing surgery. While this increase persisted into T3 for two patients, a decline was observed during the same period for the other two patients. Both events are indicative of the bone consolidation process, and RUST scores at the T3 corroborate this perspective for all patients included in this study. Considering that delta ALP (T3-T1 value) was lower in patients who exhibited the highest RUST score, we suggest that a synchronized analysis between ALP and RUST allows medics to diagnose bone consolidation.

CONCLUSIONS

Therefore, it can be concluded that the analysis of ALP alongside RUST may be complementary for evaluating bone consolidation following tibial reamed intramedullary nailing surgery, but future studies are needed to confirm this assertion.

Promoting bone callus formation by taking advantage of the time-dependent fracture gap strain modulation

Delayed union and non-union of fractures continue to be a major problem in trauma and orthopedic surgery. These cases are challenging for the surgeon. In addition, these patients suffer from multiple surgeries, pain and disability. Furthermore, these cases are a major burden on healthcare systems. The scientific community widely agrees that the stability of fixation plays a crucial role in determining the outcome of osteosynthesis. The extent of stabilization affects factors like fracture gap strain and fluid flow, which, in turn, influence the regenerative processes positively or negatively. Nonetheless, a growing body of literature suggests that during the fracture healing process, there exists a critical time frame where intervention can stimulate the bone's return to its original form and function. This article provides a summary of existing evidence in the literature regarding the impact of different levels of fixation stability on the strain experienced by newly forming tissues. We will also discuss the timing and nature of this "window of opportunity" and explore how current knowledge is driving the development of new technologies with design enhancements rooted in mechanobiological principles.

Approach to Tibial Shaft Nonunions: Diagnosis and Management

The tibia is the most common long bone at risk for nonunion with an annual incidence ranging from 12% to 19%. This topic continues to be an area of research as management techniques constantly evolve. A foundational knowledge of the fundamental concepts, etiology, and risk factors for nonunions is crucial for success. Treatment of tibial shaft nonunions often requires a multidisciplinary effort. This article provides guidance based on the most recent literature that can be used to aid the treating provider in the diagnosis, workup, and management of tibial shaft nonunions.

Predicting Union, Osteomyelitis, and Amputation Outcomes of Gustilo IIIC Open Tibial Fractures: A Retrospective Study

OBJECTIVE

Open tibial fractures are frequently encountered in high-energy traumas and can result in significant complications such as nonunion, osteomyelitis, and even amputation. Among open tibial fractures, Gustilo type IIIC cases are particularly challenging due to the concomitant occurrence of neurovascular injuries and soft tissue defects. This study aimed to assess factors that affect union time and complications in Gustilo IIIC tibial fractures.

METHODS

Patients who presented at our center with IIIC open tibial fractures from January 2000 to October 2020 were eligible for this retrospective analysis. Patient demographics, fracture characteristics, and the timing, number, and type of surgical intervention were documented. Outcomes of interest included union time, occurrence of osteomyelitis, and amputation. We performed univariate analyses including chi-squared test, Fischer's exact test, analysis of variance, and Kruskal-Wallis test based on the normality of the data and multivariate analyses including Cox proportional hazards model and logistic regression analyses.

RESULTS

Fifty-eight patients were enrolled and grouped by fracture healing time; eight had timely union (13.8%); 27 had late union (46.6%); eight had delayed union (13.8%); three had nonunion (5.2%); and 12 underwent amputation (20.7%). Nine fractures (15.5%) were complicated by osteomyelitis. Union time was prolonged in cases of triple arterial injury, distal third fractures, multiple trauma with injury severity score (ISS) ≥ 16 points, and increased bone defect length. Additionally, a bone gap >50 mm, diabetes mellitus, low body mass index, and triple arterial injury in the lower leg were significant risk factors for amputation. A time from injury to definitive soft tissue coverage of more than 22 days was the major risk factor for osteomyelitis. A scoring system to predict union time was devised and the predicted probability of union within 2 years was stratified based on this score.

CONCLUSION

IIIC tibial fractures involving the distal third of the tibia, fractures with bone defects, triple arterial injury, and multiple trauma with ISS ≥16 points demonstrated delayed union, and an effective prediction system for union time was introduced in this study. Early soft tissue coverage can reduce the risk of osteomyelitis. Finally, diabetes and severe bone and soft tissue defects pose a higher risk of amputation.

Advantages and Limitations of Diabetic Bone Healing in Mouse Models: A Narrative Review

Diabetes represents a major risk factor for impaired fracture healing. Type 2 diabetes mellitus is a growing epidemic worldwide, hence an increase in diabetes-related complications in fracture healing can be expected. However, the underlying mechanisms are not yet completely understood. Different mouse models are used in preclinical trauma research for fracture healing under diabetic conditions. The present review elucidates and evaluates the characteristics of state-of-the-art murine diabetic fracture healing models. Three major categories of murine models were identified: Streptozotocin-induced diabetes models, diet-induced diabetes models, and transgenic diabetes models. They all have specific advantages and limitations and affect bone physiology and fracture healing differently. The studies differed widely in their diabetic and fracture healing models and the chosen models were evaluated and discussed, raising concerns in the comparability of the current literature. Researchers should be aware of the presented advantages and limitations when choosing a murine diabetes model. Given the rapid increase in type II diabetics worldwide, our review found that there are a lack of models that sufficiently mimic the development of type II diabetes in adult patients over the years. We suggest that a model with a high-fat diet that accounts for 60% of the daily calorie intake over a period of at least 12 weeks provides the most accurate representation.

Can "Aseptic" Looking TIBIA Non-union be Result of an Unrecognized Subclinical Infection?

Introduction

The usual cause of a distal tibial fracture is a high-energy trauma. Although multiple options are available for their treatment such as intramedullary nailing, open plating, and external fixator, each of these options might result in a non-union. Knowing the type of non-union not only allows us to guess the cause but also directs us toward the best possible treatment. Despite this, we might still get surprises on the operating table due to pre-operative misdiagnosis.

Case Report

Reporting a case of a 42-year-old male with a 15-month-old left distal tibia non-union. The index injury was a grade 1 distal third tibia fibula fracture which was fixed with a plate and screws 15 months back. All the clinical and biochemical signs hinted toward the diagnosis of an aseptic non-union and the treatment was planned accordingly. However, intraoperative findings were much different due to which the surgeons had to improvise and change the intervention to an antibiotic-coated nail.

Conclusion

Although each variety of non-union has its set of signs and symptoms, they can be misleading. Different etiologies can coexist making it difficult to give a perfect pre-operative diagnosis and management. Non-unions, especially in the tibia, thus need meticulous understanding of the underlying disease process and extensive treatment strategies.

Risk factors and healthcare costs associated with long bone fracture non-union: a retrospective US claims database analysis

BACKGROUND

Few contemporary US-based long bone non-union analyses have recently been published. Our study was designed to provide a current understanding of non-union risks and costs, from the payers' perspective.

METHODS

The Merative™ MarketScan® Commercial Claims and Encounters database was used. Patients with surgically treated long bone (femur, tibia, or humerus) fractures in the inpatient setting, from Q4 2015 to most recent, were identified. Exclusion criteria included polytrauma and amputation at index. The primary outcome was a diagnosis of non-union in the 12 and 24 months post-index. Additional outcomes included concurrent infection, reoperation, and total healthcare costs. Age, gender, comorbidities, fracture characteristics, and severity were identified for all patients. Descriptive analyses were performed. Crude and adjusted rates of non-union (using Poisson regressions with log link) were calculated. Marginal incremental cost of care associated with non-union and infected non-union and reoperation were estimated using a generalized linear model with log link and gamma distribution.

RESULTS

A total of 12,770, 13,504, and 4,805 patients with femoral, tibial, or humeral surgically treated fractures were identified, 74-89% were displaced, and 18-27% were comminuted. Two-year rates of non-union reached 8.5% (8.0%-9.1%), 9.1% (8.6%-9.7%), and 7.2% (6.4%-8.1%) in the femoral, tibial, and humeral fracture cohorts, respectively. Shaft fractures were at increased risk of non-union versus fractures in other sites (risk ratio (RR) in shaft fractures of the femur: 2.36 (1.81-3.04); tibia: 1.95 (1.47-2.57); humerus: 2.02 (1.42-2.87)). Fractures with severe soft tissue trauma (open vs. closed, Gustilo III vs. Gustilo I-II) were also at increased risk for non-union (RR for Gustilo III fracture (vs. closed) for femur: R = 1.96 (1.45-2.58), for tibia: 3.33 (2.85-3.87), RR for open (vs. closed) for humerus: 1.74 (1.30-2.32)). For all fractures, younger patients had a reduced risk of non-union compared to older patients. For tibial fractures, increasing comorbidity (Elixhauser Index 5 or greater) was associated with an increased risk of non-union. The two-year marginal cost of non-union ranged from $33K-$45K. Non-union reoperation added $16K-$34K in incremental costs. Concurrent infection further increased costs by $46K-$86K.

CONCLUSIONS

Non-union affects 7-10% of surgically treated long bone fracture cases. Shaft and complex fractures were at increased risk for non-union.

WEDGE FRAGMENT VARIATIONS OF TIBIAL SHAFT FRACTURES WITH INTRAMEDULLARY NAILING

Introduction

Tibial shaft fracture is the most common long-bone fracture, and the standard treatment is intramedullary (IM) nail fixation. Regardless of the development of this technique pseudoarthrosis remains prevalent.

Objectives

Evaluate the correlation between wedge fragment size and displacement, displacement of the main fragments of the 42B2 type, and pseudoarthrosis incidence.

Methods

We retrospectively assessed all patients with 42B2 type fracture treated with IM nailing between January, 2015 and December, 2019. Six radiographic parameters were defined for preoperative radiographs in the anteroposterior (AP) and lateral views. Another six parameters were defined for postoperative radiographs at three, six, and 12 months. The Radiographic Union Score for Tibial Fractures score was used to assess bone healing.

Results

Of 355 patients with tibial shaft fractures, 51 were included in the study. There were 41 (82.0%) male patients, with a mean age of 36.7 years, 37 (72.5%) had open fractures, and 28 (54.9%) had associated injuries. After statistical analysis, the factors that correlated significantly with nonunion were wedge height > 18 mm, preoperative translational displacement of the fracture in the AP view > 18 mm, and final distance of the wedge in relation to its original anatomical position after IM nailing > 5 mm.

Conclusion

Risk factors for nonunion related to the wedge and42B2 fracture are wedge height > 18 mm, initial translation in the AP view of the fracture > 18 mm, and distance > 5 mm of the wedge from its anatomical position after IM nailing. Evidence level III; Retrospective comparative study .

Open fractures: Current treatment perspective

Severe open fractures present challenges to orthopaedic surgeons worldwide, with increased risks of significant complications. Although different global regions have different resources and systems, there continue to be many consistent approaches to open fracture care. Management of these complex injures continues to evolve in areas ranging from timing of initial operative debridement to the management of critical-sized bone defects. This review, compiled by representative members of the International Orthopaedic Trauma Association, focuses on several critical areas of open fracture management, including antibiotic administration, timing of debridement, bone loss, soft tissue management, and areas of need for future investigation.

Butterfly fragments in diaphyseal tibial fractures heal unpredictably: Should we be adopting other strategies for these high risk fractures?

INTRODUCTION

The natural history of diaphyseal tibial butterfly fragments is poorly documented. Numerous studies have analyzed risk factors for nonunions in the tibial shaft with known factors including Gustilo classification, ASA class, and cortical contact. However, the healing potential and ideal management of nonsegmental butterfly fragments in this setting remains unknown. The aim of this study was to determine the nonunion rate of diaphyseal tibial fractures with a butterfly fragment.

METHODS

A performed a retrospective review of patients at a single academic Level 1 Trauma Center from 2000-2020 who underwent intramedullary nailing of tibial shaft fractures. Those with non-segmental butterfly fragments (OTA/AO: 42-B) and minimum 12 month follow up were included. Morphologic measurements of butterfly fragments were performed to measure location, size, and displacement, and mRust scores at final follow up were calculated. Outcome measures were surgery to promote union, and mRust scores.

RESULTS

A total of 99 patients were included with 21 patients requiring revision surgery to promote union. Thirty six patients had open fractures and 77% of patients were male with a mean age of 34 (range: 12-80). Average follow up was 19 months (3 months - 12 years). The most common location of the butterfly fragment was the anterior cortex (42%), with a mean length of 7.8cm (SD: 3.3) and width of 1.8cm (SD: 0.5cm). At final follow-up 37% of fractures had persistent lucency without callus at the site of the butterfly while only 31% of fractures had remodeled cortex. Average time to complete healing was 13.3 months. Open fractures with butterfly fragments were more likely to go on to nonunion than closed (44% vs 9.2%, p=<0.001). The length of the butterfly fragment was not different between the union and nonunion groups (7.7 vs 7.5, P=0.42).

CONCLUSIONS

Open tibial shaft fractures with a butterfly fragment have a high risk of nonunion. Further research may seek to determine if adjunct treatment of butterfly fragments (ie inter-fragmentary compression) in the acute setting could improve healing rates.

Are pre- and postoperative true translational and angular displacement predictive of nonunion after intramedullary nail fixation of tibial shaft fractures?

PURPOSE

To determine if there is an association between pre-/postoperative translational and angular displacement with nonunion after intramedullary nail (IMN) fixation of tibial shaft fractures.

METHODS

Retrospective review of 120 patients with tibial shaft fractures undergoing IMN at an urban level-one trauma center was performed. Demographics, injury characteristics, and pre-/postoperative translational and angular fracture displacement in the coronal and sagittal planes were recorded. True fracture translational and angular displacement (TTD and TAD) were calculated by combining sagittal and coronal displacement utilizing the Pythagorean theorem.

RESULTS

10.8% of patients (n = 13) developed nonunion with remaining patients serving as the control. Groups were similar across age, sex, and BMI. Univariate analysis revealed no difference in pre-/postoperative TAD between nonunion and union groups and an increased preoperative TTD (median difference (MD): 6.2 mm, CI: 1.4-10.8 mm) and postoperative TTD (MD: 1.8 mm, CI: 0-3.7 mm) in the nonunion group. On multivariate analysis, however, only tobacco use and type 2 or 3 open fractures were associated with nonunion (OR: 5.1, CI: 1.2-22.8 and OR: 4.9, CI: 1.2-19.2, respectively).

CONCLUSION

True translational and angular displacement of tibial shaft fractures before and after IMN fixation were not independently associated with nonunion. Tobacco use and type 2 or 3 open fracture are independent factors for nonunion.

Combination of radiographic apparent bone gap and nonunion risk determination score improves accuracy of prediction of tibial shaft delayed union

BACKGROUND

There is a need for a novel therapeutic strategy for an earlier prediction of long bone union failure as compared to previous methodologies. This study aimed to determine whether a combination of two diagnostic tools would result in a more accurate diagnosis of delayed union.

METHODS

The inclusion criteria were as follows: patients with tibial shaft fracture who underwent treatment with intramedullary nailing (IMN) as definitive internal fixation (IF). The study included a total of 114 patients with 116 tibial shaft fractures treated with IMN as definitive IF. Radiographic apparent bone gap (RABG) and nonunion risk determination score (NURDS) can be used to predict nonunion. However, this study aimed to determine whether combination of RABG and NURDS could help deduce a more accurate prediction of delayed union.

RESULTS

The union rate was found to be 85% (99 fractures), the delayed union rate was found to be 15% (17 fractures), and the rate of nonunion requiring additional surgical intervention was estimated to be 4% (5 out of the 17 delayed union cases). Sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of RABG were found to be 82.3%, 76.0%, 36.8%, and 96.2%, respectively, when an RABG cutoff value of 5.0 mm was applied to our patient cohort. The sensitivity, specificity, PPV, and NPV of NURDS were found to be 47.1%, 82.0%, 30.8%, and 90.1%, respectively, when a NURDS cutoff value of 8.0% was applied to our patient cohort. When RABG and NURDS were above their respective cutoff values, the sensitivity and PPV were estimated to be 90.0% and 56.3%, respectively. When RABG and NURDS were below their respective cutoff values, the specificity and NPV were estimated to be 90.1% and 98.5%, respectively.

CONCLUSIONS

The combination of RABG and NURDS evaluation immediately after surgery helps surgeons identify patients who are at a high risk of delayed union, facilitating careful monitoring of these patients and consideration of additional treatments.

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.

Evaluation of the orthopaedic trauma association open fracture classification (OTA-OFC) as an outcome prediction tool in open tibial shaft fractures

INTRODUCTION

It was the goal of this study to determine if the Orthopaedic Trauma Association Open Fracture Classification (OTA-OFC) correlates with complication rates and to determine if it can be used as a predictive tool in the treatment of open tibial shaft fractures.

MATERIALS AND METHODS

Retrospective review from two high-volume level 1 trauma centers of open tibial shaft fractures over a 5 year period. Variables of interest included OTA-OFC, type of wound closure, 90-day wound complication, unplanned re-operation, non-union, and amputation.

RESULTS

501 consecutive open tibial shaft fractures. 57.3% (n = 287) were closed primarily; local soft tissue advancement/rotational flap was used in 9.6% (n = 48); free soft tissue transfer used in 22.8% (n = 114); 8.6% (n = 43) required amputation. Of those followed for 90 days (n = 419), 45 (9.0%) had a wound complication, of which 40 (8%) required an unplanned reoperation. 40 (8.0%) patients went on to a documented non-union. All OTA-OFC classification groups significantly correlated with type of definitive closure (r = 0.18-0.81, p < 0.05) with OTA-OFC skin showing the strongest correlation (r = 0.81). OTA-OFC bone loss weakly correlated with wound complication (r = 0.12, p = 0.02) and no OTA-OFC classification correlated with the need for an unplanned secondary procedure. OTA-OFC skin, muscle and arterial all weakly correlated with non-union (r = 0.18-0.25, p < 0.05). OTA-OFC muscle was predictive of non-union (OR = OR = 2.2, 95% CI = 1.2-4.1) and amputation (OR 9.3, 95% CI = 3.7-23.7). OTA-OFC arterial was also predictive of amputation (OR 4.8, 95% CI = 2.5-9.3).

CONCLUSIONS

The OTA-OFC correlates variably with the type of definitive closure, the development of a 90-day wound complication, and the occurrence of a non-union. Importantly, OTA-OFC muscle classification is predictive of non-union while both OTA-OFC muscle and arterial were predictive of amputation.

[Update on non-unions 2022 : Imaging diagnostics, classification and treatment algorithms]

BACKGROUND

Fracture healing is a complex regenerative process. An unconsolidated fracture that will not heal without further surgical intervention is called non-union. The causes are multifactorial. Diagnostic imaging is a central pillar and provides insights into the morphology and biology of the fracture as a basis for optimal surgical treatment decisions.

AIM

Knowledge of fracture healing, targeted radiological and nuclear medical diagnostics, and interdisciplinary standardized classification are of high importance for optimal treatment.

METHODS

In this article, the proven and modern diagnostic procedures are presented, an overview of the currently used scoring and classification models is given and the optimal therapeutic approach based on the extended "diamond concept" is addressed. A possible diagnostic and therapeutic approach is shown using an algorithm.

CONCLUSION

For successful treatment of pseudarthrosis, targeted radiological and nuclear medical diagnostics with old established but also newest methods, such as dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) and hybrid imaging, are necessary. An exact classification of non-unions using additional classification models makes it possible to determine and carry out the optimal surgical treatment at an early stage.

Base Deficit ≥ 6 within 24 h of Injury is a risk factor for fracture nonunion in the polytraumatized patient

BACKGROUND

Polytrauma patients are at risk for fracture nonunion, but the reasons are poorly understood. Increased base deficit (BD) is associated with hypovolemic shock. Although shock delays bone healing in animal models, there have been no clinical studies evaluating the impact of BD on nonunion risk.

MATERIALS AND METHODS

Patients age ≥ 16 with injury severity score > 16 that presented to an academic Level One trauma center with an operative femur or tibia fracture were reviewed. Clinical notes and radiographs were assessed to determine fracture healing status. Patient demographics, injury characteristics, BD, and number of packed red blood cell transfusions were recorded. Bivariate and multivariate analyses of multiple risk factors associated with nonunion were conducted to investigate the association of BD with nonunion.

RESULTS

The union group was comprised of 243 fractures; there were 36 fractures in the nonunion group. The following predictors were associated with nonunion: smoking (p = 0.009), alcohol use (p < 0.001), open fracture (p < 0.001), and treatment for deep infection at fracture site (p = 0.016). Additionally, worst BD over 24 h ≥ 6 (p = 0.031) was significant for nonunion development. A multivariate logistic regression analysis revealed worst BD ≥6 over 24 h remained significantly associated with the development of nonunion (odds ratio 3.02, p = 0.011) when adjusting for other risk factors.

CONCLUSIONS

A BD ≥ 6 within 24 h of admission was associated with a significantly increased risk of developing lower extremity fracture nonunion in polytrauma patients, even after adjusting for multiple other risk factors. Acute post-traumatic acidosis may have effects on long-term fracture healing.

Individualized Determination of the Mechanical Fracture Environment After Tibial Exchange Nailing-A Simulation-Based Feasibility Study

Non-union rate after tibial fractures remains high. Apart from largely uncontrollable biologic, injury, and patient-specific factors, the mechanical fracture environment is a key determinant of healing. Our aim was to establish a patient-specific simulation workflow to determine the mechanical fracture environment and allow for an estimation of its healing potential. In a referred patient with failed nail-osteosynthesis after tibial-shaft fracture exchange nailing was performed. Post-operative CT-scans were used to construct a three-dimensional model of the treatment situation in an image processing and computer-aided design system. Resulting forces, computed in a simulation-driven workflow based on patient monitoring and motion capturing were used to simulate the mechanical fracture environment before and after exchange nailing. Implant stresses for the initial and revision situation, as well as interfragmentary movement, resulting hydrostatic, and octahedral shear strain were calculated and compared to the clinical course. The simulation model was able to adequately predict hardware stresses in the initial situation where mechanical implant failure occurred. Furthermore, hydrostatic and octahedral shear strain of the revision situation were calculated to be within published healing boundaries—accordingly the fracture healed uneventfully. Our workflow is able to determine the mechanical environment of a fracture fixation, calculate implant stresses, interfragmentary movement, and the resulting strain. Critical mechanical boundary conditions for fracture healing can be determined in relation to individual loading parameters. Based on this individualized treatment recommendations during the early post-operative phase in lower leg fractures are possible in order to prevent implant failure and non-union development.

Pilot study of micromotion nailing for mechanical stimulation of tibial fracture healing

Aims

The study objective was to prospectively assess clinical outcomes for a pilot cohort of tibial shaft fractures treated with a new tibial nailing system that produces controlled axial interfragmentary micromotion. The hypothesis was that axial micromotion enhances fracture healing compared to static interlocking.

Methods

Patients were treated in a single level I trauma centre over a 2.5-year period. Group allocation was not randomized; both the micromotion nail and standard-of-care static locking nails (control group) were commercially available and selected at the discretion of the treating surgeons. Injury risk levels were quantified using the Nonunion Risk Determination (NURD) score. Radiological healing was assessed until 24 weeks or clinical union. Low-dose CT scans were acquired at 12 weeks and virtual mechanical testing was performed to objectively assess structural bone healing.

Results

A total of 37 micromotion patients and 46 control patients were evaluated. There were no significant differences between groups in terms of age, sex, the proportion of open fractures, or NURD score. There were no nonunions (0%) in the micromotion group versus five (11%) in the control group. The proportion of fractures united was significantly higher in the micromotion group compared to control at 12 weeks (54% vs 30% united; p = 0.043), 18 weeks (81% vs 59%; p = 0.034), and 24 weeks (97% vs 74%; p = 0.005). Structural bone healing scores as assessed by CT scans tended to be higher with micromotion compared to control and this difference reached significance in patients who had biological comorbidities such as smoking.

Conclusion

In this pilot study, micromotion fixation was associated with improved healing compared to standard tibial nailing. Further prospective clinical studies will be needed to assess the strength and generalizability of any potential benefits of micromotion fixation.

Cite this article: Bone Jt Open 2021;2(10):825–833.

A Machine Learning Algorithm to Identify Patients at Risk of Unplanned Subsequent Surgery After Intramedullary Nailing for Tibial Shaft Fractures

OBJECTIVES

In the SPRINT trial, 18% of patients with a tibial shaft fracture (TSF) treated with intramedullary nailing (IMN) had one or more unplanned subsequent surgical procedures. It is clinically relevant for surgeon and patient to anticipate unplanned secondary procedures, other than operations that can be readily expected such as reconstructive procedures for soft tissue defects. Therefore, the objective of this study was to develop a machine learning (ML) prediction model using the SPRINT data that can give individual patients and their care team an estimate of their particular probability of an unplanned second surgery.

METHODS

Patients from the SPRINT trial with unilateral TSFs were randomly divided into a training set (80%) and test set (20%). Five ML algorithms were trained in recognizing patterns associated with subsequent surgery in the training set based on a subset of variables identified by random forest algorithms. Performance of each ML algorithm was evaluated and compared based on (1) area under the ROC curve, (2) calibration slope and intercept, and (3) the Brier score.

RESULTS

Total data set comprised 1198 patients, of whom 214 patients (18%) underwent subsequent surgery. Seven variables were used to train ML algorithms: (1) Gustilo-Anderson classification, (2) Tscherne classification, (3) fracture location, (4) fracture gap, (5) polytrauma, (6) injury mechanism, and (7) OTA/AO classification. The best-performing ML algorithm had an area under the ROC curve, calibration slope, calibration intercept, and the Brier score of 0.766, 0.954, -0.002, and 0.120 in the training set and 0.773, 0.922, 0, and 0.119 in the test set, respectively.

CONCLUSIONS

An ML algorithm was developed to predict the probability of subsequent surgery after IMN for TSFs. This ML algorithm may assist surgeons to inform patients about the probability of subsequent surgery and might help to identify patients who need a different perioperative plan or a more intensive approach.

LEVEL OF EVIDENCE

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

Predicting fracture healing with blood biomarkers: the potential to assess patient risk of fracture nonunion

Fracture non-union is a significant orthopaedic problem affecting a substantial number of patients yearly. Treatment of nonunions is devastating to patients and costly to the healthcare system. Unfortunately, the diagnosis of non-union is typically made in a reactionary fashion by an orthopaedic surgeon based on clinical assessment and radiographic features several months into treatment. For this reason, investigators have been trying to develop prediction algorithms; however, these have relied on population-based approaches and lack the predictive capability necessary to make individual treatment decisions. There is also a growing body of literature focussed on identifying blood biomarkers that are associated with non-union. This review describes the research that has been done in this area. Further studies of patient-centered, precision medicine approaches will likely improve fracture non-union diagnostic/prognostic capabilities.

Factors predicting failure of internal fixations of fractures of the lower limbs: a prospective cohort study

Background

We assessed predictive factors of patients with fractures of the lower extremities caused by trauma. We examined which factors are associated with an increased risk of failure. Furthermore, the predictive factors were set into context with other long-term outcomes, concrete pain and physical functioning.

Methods

We performed a prospective cohort study at a single level I trauma center. We enrolled patients with traumatic fractures of the lower extremities treated with internal fixation from April 2017 to July 2018. We evaluated the following predictive factors: age, gender, diabetes, smoking status, obesity, open fractures and peripheral arterial diseases. The primary outcome was time to failure (nonunion, implant failure or reposition). Secondary outcomes were pain and physical functioning measured 6 months after initial surgery. For the analysis of the primary outcome, we used a stratified (according fracture location) Cox proportional hazard regression model.

Results

We included 204 patients. Overall, we observed failure in 33 patients (16.2 %). Most of the failures occurred within the first 3 months. Obesity and open fractures were associated with an increased risk of failure and decreased physical functioning. None of the predictors showed an association with pain. Age, female gender and smoking of more than ≥ 10 package years increased failure risk numerically but statistical uncertainty was high.

Conclusions

We found that obesity and open fractures were strongly associated with an increased risk of failure. These predictors seem promising candidates to be included in a risk prediction model and can be considered as a good start for clinical decision making across different types of fractures at the lower limbs. However, large heterogeneity regarding the other analyzed predictors suggests that “simple” models might not be adequate for a precise personalized risk estimation and that computer-based models incorporating a variety of detailed information (e.g. pattern of injury, x-ray and clinical data) and their interrelation may be required to significantly increase prediction precision.

Trial registration

NCT03091114.

Non-union bone fractures

The human skeleton has remarkable regenerative properties, being one of the few structures in the body that can heal by recreating its normal cellular composition, orientation and mechanical strength. When the healing process of a fractured bone fails owing to inadequate immobilization, failed surgical intervention, insufficient biological response or infection, the outcome after a prolonged period of no healing is defined as non-union. Non-union represents a chronic medical condition not only affecting function but also potentially impacting the individual's psychosocial and economic well-being. This Primer provides the reader with an in-depth understanding of our contemporary knowledge regarding the important features to be considered when faced with non-union. The normal mechanisms involved in bone healing and the factors that disrupt the normal signalling mechanisms are addressed. Epidemiological considerations and advances in the diagnosis and surgical therapy of non-union are highlighted and the need for greater efforts in basic, translational and clinical research are identified.

Scoring systems for early prediction of tibial fracture non-union: an update

Purpose

To evaluate the available tibial fracture non-union prediction scores and to analyse their strengths, weaknesses, and limitations.

Methods

The first part consisted of a systematic method of locating the currently available clinico-radiological non-union prediction scores. The second part of the investigation consisted of comparing the validity of the non-union prediction scores in 15 patients with tibial shaft fractures randomly selected from a Level I trauma centre prospectively collected database who were treated with intramedullary nailing.

Results

Four scoring systems identified: The Leeds-Genoa Non-Union Index (LEG-NUI), the Non-Union Determination Score (NURD), the FRACTING score, and the Tibial Fracture Healing Score (TFHS). Patients demographics: Non-union group: five male patients, mean age 36.4 years (18–50); Union group: ten patients (8 males) with mean age 39.8 years (20–66). The following score thresholds were used to calculate positive and negative predictive values for non-union: FRACTING score ≥ 7 at the immediate post-operative period, LEG-NUI score ≥ 5 within 12 weeks, NURD score ≥ 9 at the immediate post-operative period, and TFHS < 3 at 12 weeks. For the FRACTING, LEG-NUI and NURD scores, the positive predictive values for the development of non-union were 80, 100, 40% respectively, whereas the negative predictive values were 60, 90 and 90%. The TFHS could not be retrospectively calculated for robust accuracy.

Conclusion

The LEG-NUI had the best combination of positive and negative predictive values for early identification of non-union. Based on this study, all currently available scores have inherent strengths and limitations. Several recommendations to improve future score designs are outlined herein to better tackle this devastating, and yet, unsolved problem.

NURD 2.0: Prediction of tibial nonunion after intramedullary nail fixation at any time within 3 months after injury

Introduction Nonunion after fixation of long bones negatively impacts outcomes and requires additional surgery. The ability to predict likelihood of nonunion after tibial shaft fracture would be helpful to clinicians and patients. The goal of this work was to combine three previous models of tibial shaft nonunion at different time points into one overall model that incorporates time as a continuous variable. Methods We conducted a retrospective review at a Level I academic trauma center. The study cohort consisted of patients with tibial shaft fractures treated with nail insertion from 2007 through 2014, excluding patients who did not have contact between bone ends, those who had planned bone grafting for acute bone defects, and those who lacked adequate follow-up. Three previous models were combined: 382 patients at time 0, 323 at 6 weeks, and 240 at 12 weeks. The primary outcome variable was surgery for nonunion. Bivariate and multivariate regression analyses determined which of 42 clinical and radiographic variables were significantly associated with nonunion. Predictive power was evaluated using area under the curve (AUC). Results The original nonunion risk determination (NURD) score was significantly improved through addition of 6- and 12-week radiographic union scores for tibial fractures, infection and complications, smoking status, and need for flaps. Overall, over the course of 12 weeks, the NURD-based model produced an AUC of 0.87 at initial time of fixation that improved to >0.9 at 6 and 12 weeks. Data were used to bin patients into five clinically important risk strata (p < 0.001). Patients in the lowest risk strata had 0% probability of nonunion (0 of 97 patients); in the second lowest risk strata, 4% (three of 73 patients); and in the highest risk strata, 48% (38 of 80 patients). Conclusions We created a NURD 2.0 score that predicts nonunion at various time points during the first 3 months after fracture. The new model is a notable improvement over previous models. A computerized version allows surgeons and patients to use the score when making treatment decisions regarding need for nonunion surgery.

Prediction of delayed union of tibial shaft fracture treated with intramedullary nailing: multicenter-study analysis and literature review -the TRON study

PURPOSE

We aimed to 1) identify predictors of delayed and nonunion of tibial shaft fractures in patients treated with intramedullary nailing (IMN), including patient demographics and surgical factors, and 2) determine whether the nail/shaft ratio is associated with delayed and nonunion.

METHODS

This retrospective, multicenter study included 315 patients with tibial shaft fracture treated with IMN between 2014 and 2019 and excluded patients with insufficient follow-up for 12 months, lost data and inadequate radiographs. Finally, we analyzed 258 patients (184 males; 74 females). Main outcome measurements were delayed union at 6 and nonunion at 12 months after surgery as determined on anteroposterior and lateral radiographs. We extracted the following as risk factors of delayed and nonunion: age, sex, BMI, fracture site, fracture type, injury energy, smoking history, and nail/shaft ratio. We conducted logistic regression analysis to investigate risk factors of delayed and nonunion using these extracted items as explanatory variables.

RESULTS

Type C fracture was independently associated with delayed union (odds ratio 2.9, 95% confidential interval: 1.04-8.09, P = 0.04). Nail/shaft ratio was not an independent factor of delayed union. No independent explanatory factors were related to nonunion.

CONCLUSIONS

Type C fractures, which were unstable and fragmented, was associated with delayed union in tibia fractures treated with IMN, whereas nail thickness was not associated with delayed or nonunion fractures.

Civilian Ballistic Tibia Shaft Fractures Compared With Blunt Tibia Shaft Fractures: Open or Closed?

OBJECTIVES

To identify a group of ballistic tibia fractures, report the outcomes of these fractures, and compare them with both closed and open tibia fractures sustained by blunt mechanisms. We hypothesized that ballistic tibia fractures and blunt open fractures would have similar outcomes.

DESIGN

Retrospective cohort study.

SETTING

A single Level-1 trauma center.

PATIENTS/PARTICIPANTS

Adult patients presenting with ballistic (44), blunt closed (179), or blunt open (179) tibia fractures.

INTERVENTION

Intramedullary stabilization of tibia fracture.

MAIN OUTCOMES

Unplanned reoperation, soft tissue reconstruction, nonunion, compartment syndrome, and fracture-related infection.

RESULTS

Compared with the blunt closed group, the ballistic fracture group required more operations (P < 0.01), had a higher occurrence of soft tissue reconstruction (P < 0.01), and higher incidence of compartment syndrome (P = 0.02). Ballistic and blunt closed groups did not significantly differ in rates of unplanned reoperation (P = 0.67), nonunion (11.4% vs. 4.5%, P = 0.08), or deep infection (9.1% vs. 5.6%, P = 0.49). In comparison to the blunt open group, the ballistic group required a similar number of operations (P = 0.12), had similar rates of unplanned reoperation (P = 0.10), soft tissue reconstruction (P = 0.56), nonunion (11.4% vs. 17.9%, P = 0.49), and fracture-related infection (9.1% vs. 10.1%, P = 1.0) but a higher incidence of compartment syndrome (15.9% vs. 5.0%, P = 0.02).

CONCLUSIONS

Ballistic tibia fractures require more surgeries and have higher rates of soft tissue reconstruction than blunt closed fractures and seem to have outcomes similar to lower severity open fractures. We found a significantly higher rate of compartment syndrome in ballistic tibia fractures than both open and closed blunt fractures. When treating ballistic tibia fractures, surgeons should maintain a high level of suspicion for the development of compartment syndrome and counsel patients that ballistic tibia fractures seem to behave like an intermediate category between closed and open fractures sustained through blunt mechanisms.

LEVEL OF EVIDENCE

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

Compilation and Analysis of Web-Based Orthopedic Personalized Predictive Tools: A Scoping Review

Web-based personalized predictive tools in orthopedic surgery are becoming more widely available. Despite rising numbers of these tools, many orthopedic surgeons may not know what tools are available, how these tools were developed, and how they can be utilized. The aim of this scoping review is to compile and synthesize the profile of existing web-based orthopedic tools. We conducted two separate PubMed searches-one a broad search and the second a more targeted one involving high impact journals-with the aim of comprehensively identifying all existing tools. These articles were then screened for functional tool URLs, methods regarding the tool's creation, and general inputs and outputs required for the tool to function. We identified 57 articles, which yielded 31 unique web-based tools. These tools involved various orthopedic conditions (e.g., fractures, osteoarthritis, musculoskeletal neoplasias); interventions (e.g., fracture fixation, total joint arthroplasty); outcomes (e.g., mortality, clinical outcomes). This scoping review highlights the availability and utility of a vast array of web-based personalized predictive tools for orthopedic surgeons. Increased awareness and access to these tools may allow for better decision support, surgical planning, post-operative expectation management, and improved shared decision-making.

Biomedical research models in the science of fracture healing - Pitfalls & promises

Development of intervention strategies to stimulate fracture healing has long been a focus of musculoskeletal research. Considerable investment in empirical research has led to the discovery of several genes and signaling pathways that are involved in skeletal development and regeneration. However, there are currently very few biologic interventions that can efficiently be used to enhance fracture healing in clinical practice. This translational barrier is due in part to experimental barriers to mechanism discovery. Animal models, biomechanical models, finite element models, and mathematical models are a few examples of models that aid in the discovery of mechanisms. Understanding the advantages, limitations, and specialized uses of each model type is critical to our ability to interpret mechanistic insights from such research and to help bridge the translation gap between pre-clinical research and clinical practice. In this review, we look at specific modeling methods used in the study of the fracture healing mechanism. We also discuss the strength and limitations to translation of each method, hopefully leading to a better understanding of how we can use models to advance the study of fracture healing.

Predicting tibia shaft nonunions at initial fixation: An external validation of the Nonunion Risk Determination (NURD) score in the SPRINT trial data

BACKGROUND

Predictive models are common in orthopedic research; however, most models are not validated in an external population. The Nonunion Risk Determination (NURD) score was developed using a single-center cohort of 382 patients to reliably predict tibia shaft nonunions at the time of initial intramedullary nail fixation. The purpose of this study was to externally validate the NURD score using data from the SPRINT Trial.

METHODS

The SPRINT trial was a multicenter study comparing reamed versus unreamed intramedullary nails in tibial shaft fracture patients. We assessed the prognostic performance of the NURD score in the SPRINT trial data with comparisons of the c-statistics, calibration plots, and a comparison of predicted probabilities at cut-points defined in the study to derive the NURD score. In addition, we compared the odds ratios of the NURD score components between the derivation (NURD) and external validation (SPRINT) data.

RESULTS

The NURD score demonstrated significantly worse discrimination in the SPRINT data than was observed in the original data (c-statistic: 0.61 vs. 0.85, p<0.01). The NURD score was well-calibrated in the derivation and SPRINT data. The SPRINT data had less heterogeneity, as determined by the standard deviation of the linear predictors (NURD: 1.4 vs.

SPRINT

0.4). Once we adjusted for case-mix differences, the NURD score had similarly strong discrimination in the SPRINT data (c-statistic: 0.81 vs. 0.85, p = 0.17).

DISCUSSION

Based on our external validation, the NURD score lacks generalizability as it underperforms with respect to discrimination in the SPRINT trial data. However, after adjusting for case-mix differences, the performance of the NURD score is comparable between the two datasets, suggesting robust reproducibility.

Prevalence and influencing factors of nonunion in patients with tibial fracture: systematic review and meta-analysis

OBJECTIVE

The aim of this study is to assess the prevalence of nonunion in patients with tibia fracture and the association between influencing factors and tibia fracture nonunion.

METHOD

A database searches of PubMed, the Cochrane Library, EMBASE, China National Knowledge Infrastructure (CNKI), Weipu database, and Wanfang database from inception until June 2019 was conducted. The pooled prevalence, odds ratio (OR), and 95% confidence intervals (CI) were calculated with Stata software.

RESULTS

In this study, 111 studies involving 41,429 subjects were included. In the study of the relationship between influencing factors and tibia fracture nonunion, 15 factors significantly influenced the fracture union, including > 60 years old, male, tobacco smoker, body mass index > 40, diabetes, nonsteroidal anti-inflammatory drugs (NSAIDs) user, opioids user, fracture of middle and distal tibia, high-energy fracture, open fracture, Gustilo-Anderson grade IIIB or IIIC, Müller AO Classification of Fractures C, open reduction, fixation model, and infection.

CONCLUSION

The prevalence of nonunion in patients with tibia fracture was 0.068 and 15 potential factors were associated with the prevalence. Closed reduction and minimally invasive percutaneous plate osteosynthesis (MIPPO) have the low risks of nonunion for the treatment of tibial fractures.

The Life of a Fracture: Biologic Progression, Healing Gone Awry, and Evaluation of Union

New knowledge about the molecular biology of fracture-healing provides opportunities for intervention and reduction of risk for specific phases that are affected by disease and medications. Modifiable and nonmodifiable risk factors can prolong healing, and the informed clinician should optimize each patient to provide the best chance for union. Techniques to monitor progression of fracture-healing have not changed substantially over time; new objective modalities are needed.

Factors associated with subsequent surgical procedures after intramedullary nailing for tibial shaft fractures

Introduction

The reported rate of subsequent surgery after intramedullary nailing (IMN) of tibial shaft fractures (TSFs) is as high as 21%. However, most studies have not included the removal of symptomatic implant in these rates. The purpose of this study was to evaluate the subsequent surgery rate after IMN of TSFs, including the removal of symptomatic implants. Secondly, this study aimed to assess what factors are associated with subsequent surgery (1) to promote fracture and wound healing and (2) for the removal of symptomatic implants.

Methods

One-hundred and ninety-one patients treated with IMN for TSFs were retrospectively included. The rate of subsequent surgery was determined. Bi- and multivariable analysis was used to identify variables associated with subsequent surgery.

Results

Approximately half of patients (46%) underwent at least one subsequent surgical procedure. Forty-eight (25%) underwent a subsequent surgical procedure to promote fracture or wound healing. Age (P < 0.01), multi-trauma (P < 0.01), open fracture (P < 0.001) and index surgery during weekdays (P < 0.05) were associated with these procedures. Thirty-nine patients (20%) underwent a subsequent surgical procedure for removal of symptomatic implants. There was a significantly lower rate of implant removal in ASA II (11%) and ASA III–IV (14%) patients compared to ASA I patients (29%) (P < 0.05).

Conclusions

Patients treated with IMN for TSFs should be consented that about one-in-two patients will undergo an additional surgical procedure. Half of these procedures are required to promote wound or fracture healing; the other half are for symptomatic implant removal.

Level of evidence

Therapeutic level-IV.

Tibial Fracture Healing Score: A Novel Tool to Predict Tibial Nonunion

The aim of the study was to investigate the utility of a simple office-based tool in predicting the need for secondary intervention to obtain union in patients with tibial fractures. All patients 18 years and older with isolated tibial shaft fractures (OTA 41A, 42A-C, and 43A) treated with intramedullary nailing from 2013 to 2017 were screened. Eighty-seven patients met enrollment criteria. Surgeon assessment of the following 3 clinical parameters was performed at routine office visits and scored as follows: (1) pain (none/mild/decreased=1, no change/increased=0); (2) function (minimal limp/able to perform a single-leg stance=1, significant limp/unable to perform single-leg stance=0); and (3) examination (no/minimal pain with manipulation=1, pain with manipulation=0). Radiographic healing was assessed by the adjusted radiographic union scale in tibial fractures (aRUST). The tibial fracture healing score (TFHS) is the sum of 3 clinical scores (0 to 3) and aRUST score (1 to 3) at 3 months postoperatively. The overall nonunion rate was 11%. A RUST score of 5 or less and a sum of the 3 clinical scores of less than 2 at 3 months were found be predictive of nonunion. A TFHS of less than 3 at 3 months was more reliable in identifying patients requiring nonunion repair, especially for those with minimal radiographic healing (RUST score 6 or 7) at 3 months. The TFHS is a simple office-based clinical tool that may identify patients at high risk of nonunion (TFHS <3) following isolated tibial shaft fracture more effectively than clinical examination or radiographic assessment alone. [Orthopedics. 2020;43(4);e323-e328.].

Complications and subsequent surgery after intra-medullary nailing for tibial shaft fractures: Review of 8110 patients

BACKGROUND

Intramedullary nailing of tibial shaft fractures has been common practice for decades. Nevertheless, complications occur frequently, and subsequent surgery is often required. To improve our understanding on how we may improve trauma care for patients with tibial shaft fractures, this study systematically reviewed all currently available evidence to assess the incidence of complications and rate of re-operations following intramedullary nailing of traumatic tibial fractures.

METHODS

Trip Database, Medline, Scopus and Cochrane Library were searched on September 7th, 2018. Searches were limited to English studies published after January 1st, 1998. Studies were included if authors included more than 50 patients treated with intramedullary nailing for traumatic tibial fractures. Inclusion of studies and critical appraisal of the evidence was performed by two independent authors. Incidence of complications and rate of re-operations were reported with descriptive statistics.

RESULTS

Fifty-one studies involving 8110 patients treated with intramedullary nailing for traumatic tibial fractures were included. Mean age of patients was 37.5 years. The most frequent complication was anterior knee pain (23%), followed by non-union (11%). Eighteen percent of patients required at least one subsequent surgery. The most frequent indication of subsequent surgery was screw removal due to pain or discomfort (9%). Dynamization of the nail to promote union was reported in 8% of the cases. Nail revision and bone-grafting to promote union were applied in 4% and 2% respectively.

DISCUSSION & CONCLUSION

Patients treated with intramedullary nailing for tibial fractures need to be consented for high probability of adverse events as anterior knee pain, subsequent surgical procedures and bone healing problems are relatively common. However, based on current data it remains difficult to identify specifiers and determinants of an individual patient with specific fracture characteristics at risk for complications. Future studies should aim to establish patient specific risks models for complications and re-operations, such that clinicians can anticipate them and adjust and individualize treatment strategies.

Epidemiology, Clinical Assessments, and Current Treatments of Nonunions

PURPOSE OF REVIEW

The failure of bony union following a fracture, termed a fracture nonunion, has severe patient morbidity and economic consequences. This review describes current consensuses and future directions of investigation for determining why, detecting when, and effective treatment if this complication occurs.

RECENT FINDINGS

Current nonunion investigation is emphasizing an expanded understanding of the biology of healing. This has led to assessments of the immune environment, multiple cytokines and morphogenetic factors, and the role of skeletogenic stem cells in the development of nonunion. Detecting biological markers and other objective diagnostic criteria is also a current objective of nonunion research. Treatment approaches in the near future will likely be dominated by the development of specific adjunct therapies to the nonunion surgical management, which will be informed by an expanded mechanistic understanding of nonunion biology. Current consensus among orthopedists is that improved diagnosis and treatment of nonunion hinges first on discoveries at the bench side with later translation to the clinic.

Predicting Functional Outcomes Following Fracture Nonunion Repair-Development and Validation of a Risk Profiling Tool

OBJECTIVES

To develop a tool that can be used preoperatively to identify patients at risk of poor functional outcome following operative repair of fracture nonunion.

DESIGN

Retrospective analysis of prospectively collected data.

SETTING

Academic medical center.

PATIENTS/PARTICIPANTS

Three hundred twenty-eight patients who underwent operative repair of a fracture nonunion were prospectively followed for a minimum of 12 months post-operatively.

INTERVENTION

After randomization, 223 (68%) patients comprised an experimental cohort and 105 (32%) patients comprised a separate validation cohort. Within the experimental cohort, forward stepwise multivariate logistic regression was applied to 17 independent variables to generate a predictive model identifying patients at risk of having a poor functional outcome [Predicting Risk of Function in Trauma-Nonunion (PRoFiT-NU) Score].

MAIN OUTCOME MEASUREMENTS

Functional outcomes were assessed using the Short Musculoskeletal Function Assessment (SMFA). Poor outcome was defined as an SMFA function index greater than 10 points above the mean at 12 months post-operatively.

RESULTS

Significant predictors of poor outcome were lower extremity nonunion [odds ratio (OR) = 3.082; P = 0.021], tobacco use (OR = 2.994; P = 0.009), worker's compensation insurance (OR = 3.986; P = 0.005), radiographic bone loss (OR = 2.397; P = 0.040), and preoperative SMFA function index (OR = 1.027; P = 0.001). The PRoFiT-NU model was significant and a good predictor of poor functional outcome (χ(5) = 51.98, P < 0.0005; area under the receiver operating curve = 0.79). Within the separate validation cohort, 16% of patients had a poor outcome at a PRoFiT-NU score below 25% (low risk), 39% of patients had a poor outcome at a PRoFiT-NU score between 25% and 50% (intermediate risk), and 63% of patients had a poor outcome at a PRoFiT-NU score above 50% (high risk).

CONCLUSIONS

The PRoFiT-NU score is an accurate predictor of poor functional outcome following fracture nonunion repair.

LEVEL OF EVIDENCE

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

Surgical treatment outcomes of the Ilizarov and internal osteosynthesis methods in posttraumatic pseudarthrosis of the tibia-a retrospective comparative analysis

Introduction

This study compared surgical treatment outcomes of the Ilizarov and internal osteosynthesis methods in posttraumatic pseudarthrosis of the tibia.

Material and methods

In a retrospective comparative study, 75 patients were treated with the Ilizarov technique for aseptic posttraumatic pseudarthrosis of the tibia in the period 2000–2016. We compared them with the 51 patients from the control group, treated for tibial bone union disturbances using internal osteosynthesis methods, i.e., internal-fixation plates and intramedullary nails. The study groups were compared in terms of the rates of union, time to union, and the baseline-to-postoperative difference in lower leg deformity.

Results

Union rate in the Ilizarov group was 100% and the control group was 51.92% (p < 0.001). The median time to union suggests that patients from the Ilizarov group needed a shorter time to achieve bone union (203.00 days vs. 271.00 days) (p = 0.091). The effect size in the Ilizarov group was larger both in terms of reducing both limb deformity and shortening (it is worth noting, however, that the Ilizarov treatment was used in patients with higher baseline values of both these parameters). We observed no significant difference in terms of time to union between the group of patients with at least one risk factor for disturbance in fracture healing and the group with no risk factors. The following risk factors were considered: diabetes mellitus, corticosteroid therapy, smoking, alcohol dependence, and advanced lower-extremity vascular disease (p = 0.827).

Discussion

Our study demonstrated a high effectiveness of the Ilizarov method in the treatment of aseptic posttraumatic pseudarthroses of the tibia. The Ilizarov method seems to be worth considering in all cases where either the patient or the nature of injury is associated with additional risk factors and whenever there is a need for leg deformity correction or leg elongation.

Radiographic evaluations: Which are most effective to follow fracture healing?

The assessment of fracture healing is an imperative and fundamental clinical aspect within orthopaedics. Despite that, there have historically been non-reliable methods utilized to assess for fracture union and nonunion. In recent years, a number of radiographic assessment tools such as the Radiographic Union Score for Tibial fractures (RUST) and Radiographic Union Score for Hip fracture (RUSH) have been developed in order to improve the reliability of fracture assessment for union. These scores have not only increased the reliability of assessments but have also provided thresholds to aid in predicting nonunion as well as union. The nonunion risk determination (NURD) Score was also created to prognosticate these clinical presentations. With the large burdens of cost, lower quality of life and morbidity associated with fracture nonunion, these evaluation methods have provided orthopaedic surgeons with an improved ability to predict nonunion and assist in the management of patients. This review outlines the development, reliability testing as well as biomechanical validity testing associated with these scoring systems.

Hardware considerations in infection and nonunion management: When and how to revise the fixation

The occurrence of both nonunion and fracture-related infection provides challenges for both the patient and the treating orthopaedic surgeon, with the potential need for complex reconstructive procedures to achieve union and/or eradicate infection. In addition to addressing the multiple different factors that often contribute to nonunion, surgeons are often forced to deal with difficult hardware issues at the time of revision surgery including infected hardware, loose or failing hardware, malaligned hardware, or inappropriate hardware constructs. This article reviews common causes of nonunions with emphasis on infection management and provides indications and techniques for hardware removal in the context of an algorithmic approach to nonunion management with illustrative case examples.

The top three unanswered questions in the management of open fractures

Despite improvements in treatment strategies and emphasis on preventative measures, the management of open fractures continues to be a challenging endeavor for orthopaedic surgeons. Deep infections, delayed healing, and nonunion continue to be problematic complications associated with these devastating injuries. There remain many unanswered clinical questions regarding the management of these injuries and how the various aspects of care can be further optimized. There continues to be a paucity of evidence regarding how infection can best be treated and prevented, how to reliability predict bone healing/nonunion, and how bone healing can be best augmented in the setting of open fractures and their potential nonunions. This review aims to assess the current literature on these top unanswered questions and discuss the gaps in evidence that may be filled with future studies.

Virtual Mechanical Testing Based on Low-Dose Computed Tomography Scans for Tibial Fracture: A Pilot Study of Prediction of Time to Union and Comparison with Subjective Outcomes Scoring

BACKGROUND

Quantitative outcomes assessment remains a persistent challenge in orthopaedic trauma. Although patient-reported outcome measures (PROMs) and radiographic assessments such as Radiographic Union Scale for Tibial Fractures (RUST) scores are frequently used, very little evidence has been presented to support their validity for measuring structural bone formation or biomechanical integrity.

METHODS

In this pilot study, a sequential cohort of patients with a tibial shaft fracture were prospectively recruited for observation following standard reamed intramedullary nailing in a level-I trauma center. Follow-up at 6, 12, 18, and 24 weeks included radiographs and completion of PROMs (EuroQol 5-Dimension [EQ-5D] and pain scores). Low-dose computed tomography (CT) scans were also performed at 12 weeks. Scans were reconstructed in 3 dimensions (3D) and subjected to virtual mechanical testing via the finite element method to assess torsional rigidity in the fractured limb relative to that in the intact bone.

RESULTS

Patients reported progressive longitudinal improvement in mobility, self-care, activity, and health over time, but the PROMs were not correlated with structural bone healing. RUST scoring showed moderate intrarater agreement (intraclass coefficient [ICC] = 0.727), but the scores at 12 weeks were not correlated with the time to union (R = 0.104, p = 0.193) and were only moderately correlated with callus structural integrity (R = 0.347, p = 0.010). In contrast, patient-specific virtual torsional rigidity (VTR) was significantly correlated with the time to union (R = 0.383, p = 0.005) and clearly differentiated 1 case of delayed union (VTR = 10%, union at 36 weeks) from the cases in the normally healing cohort (VTR > 60%; median union time, 19 weeks) on the basis of CT data alone.

CONCLUSIONS

PROMs provide insight into the natural history of the patient experience after tibial fracture but have limited utility as a measure of structural bone healing. RUST scoring, although reproducible, may not reliably predict time to union. In contrast, virtual mechanical testing with low-dose CT scans provides a quantitative and objective structural callus assessment that reliably predicts time to union and may enable early diagnosis of compromised healing.

LEVEL OF EVIDENCE

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

Precision Medicine Applications to Manage Multiply Injured Patients With Orthopaedic Trauma

Precision medicine offers potential for improved outcomes by tailoring interventions based on patient-specific demographics and disease-specific data. Precision methods are relatively unexplored in trauma patients. New research is being looked at for precision methods to treat patients with large extremity wounds, nonunions, and fractures associated with polytrauma. Precision-based clinical decision tools are being validated to optimize timing for open wound definitive closure. Early patient-specific biomarkers to stratify nonunion risk within 1 week of fracture are being explored. Patient-specific data to stage timing of major fracture interventions in multiply injured patients are being interrogated.