Fracture healing: A review of clinical, imaging and laboratory diagnostic options

Reconstruction of gap non-union tibia with composite use of extramedullary fixation and bone transport by monorail fixator: a prospective case series

Introduction

Non-union is a complex, multifactorial orthopaedic problem that requires multiple treatment modalities for its management. It can result from infection, segmental bone loss, soft-tissue loss, and associated host factors. External fixators as management of gap non-union are bulky and give rise to a number of complications In our study, we have described a technique where we have used extramedullary fixation in the form of a tibial locking plate and transportation of part of the tibial bone after corticotomy by a monorail fixator.

Materials and Methods

The procedure was done in two stages where internal and external fixation was done after creating a gap at the non-union site. The bone was transported after corticotomy and fixed to the internal fixation device in the second stage. The external fixator was removed in the second stage and the patient was then followed up till the bony union. The evaluation was done by functional and radiological assessment along with the complications noted with the described procedure.

Results

Ten patients were enrolled in the study with a mean age of 33 years. The mean age of the patients was 33.7 ± 11.32 years with a mean size of the defect was 4.8 ± 1.7 cm. At 30 weeks out of nine patients, three patients had excellent and six had good functional results on the Association of Surgeons for Application and Methodology of Ilizarov (ASAMI) scale. The composite Musculoskeletal Tumor Society (MSTS) score was 76.66 % at the end of 30 weeks of follow-up. The mean time of consolidation was 134.4 days, whereas the mean union time was 145 days from index surgery. Ankle stiffness was the most common complication affecting 50% of the patients. Following closely was pin tract infection, which was present in 40% of the patients. According to Paley's classification, there were 11 obstacles, two problems and none were true complications.

Conclusion

The integrated fixation is both safe and effective and has the advantage of early removal of the external fixator and a low complication rate as compared to use of a bulky conventional fixator alone. Moreover, it gives protection to the regenerated bone for a long period. So, this technique can be recommended for the management of segmental tibial defects.

Opioid-Sparing Nonsteroid Anti-inflammatory Drugs Protocol in Patients Undergoing Intramedullary Nailing of Tibial Shaft Fractures: A Randomized Control Trial

INTRODUCTION

Nonsteroidal anti-inflammatory drugs (NSAIDs) are effective analgesics commonly used in fracture management. Although previously associated with delayed fracture healing, multiple studies have demonstrated their safety, with minimal risks of fracture healing. Given the current opioid crisis in the United States, alternate pain control modalities are essential to reduce opioid consumption. This study aims to determine whether the combination of oral acetaminophen and intravenous ketorolac is a viable alternative to opioid-based pain management in closed tibial shaft fractures treated with intramedullary nailing.

METHODS

We conducted a randomized controlled trial evaluating postoperative pain control and opioid consumption in patients with closed tibial shaft fractures who underwent intramedullary nailing. Patients were randomized into an NSAID-based pain control group (52 patients) and an opioid-based pain control group (44 patients). Visual analog scale (VAS) scores and morphine milligram equivalents (MMEs) were evaluated at 12-hour postoperative intervals during the first 48 hours after surgery. Nonunion and delayed healing rates were recorded for both groups.

RESULTS

A statistically significant decrease in MMEs was noted at every measured interval (12, 24, 36, and 48 hours) in the NSAID group compared with the opioid group ( P -value 0.001, 0.001, 0.040, 0.024, respectively). No significant change in visual analog scale scores was observed at 12, 36, and 48 hours between both groups ( P -value 0.215, 0.12, and 0.083, respectively). A significant decrease in VAS scores was observed at the 24-hour interval in the NSAID group compared with the opioid group ( P -value 0.041). No significant differences in union rates were observed between groups ( P -value 0.820).

DISCUSSION

Using an NSAID-based postoperative pain protocol led to a decrease in opioid consumption without affecting pain scores or union rates. Owing to the minimal risk of short-term NSAID use, their role in the perioperative management of tibia shaft fractures is justified, especially when they reduce opioid consumption markedly.

LEVEL OF EVIDENCE

Therapeutic Level I.

Mobilizing Endogenous Progenitor Cells Using pSDF1α-Activated Scaffolds Accelerates Angiogenesis and Bone Repair in Critical-Sized Bone Defects

Mobilizing endogenous progenitor cells to repair damaged tissue in situ has the potential to revolutionize the field of regenerative medicine, while the early establishment of a vascular network will ensure survival of newly generated tissue. In this study, a gene-activated scaffold containing a stromal derived factor 1α plasmid (pSDF1α), a pro-angiogenic gene that is also thought to be involved in the recruitment of mesenchymal stromal cells (MSCs) to sites of injury is described. It is shown that over-expression of SDF1α protein enhanced MSC recruitment and induced vessel-like structure formation by endothelial cells in vitro. When implanted subcutaneously, transcriptomic analysis reveals that endogenous MSCs are recruited and significant angiogenesis is stimulated. Just 1-week after implantation into a calvarial critical-sized bone defect, pSDF1α-activated scaffolds are recruited MSCs and rapidly activate angiogenic and osteogenic programs, upregulating Runx2, Dlx5, and Sp7. At the same time-point, pVEGF-activated scaffolds are recruited a variety of cell types, activating endochondral ossification. The early response induced by both scaffolds leads to complete bridging of the critical-sized bone defects within 4-weeks. The versatile cell-free gene-activated scaffold described in this study is capable of harnessing and enhancing the body's own regenerative capacity and has immense potential in a myriad of applications.

Cellular therapies for bone repair: current insights

Mesenchymal stem cells are core to bone homeostasis and repair. They both provide the progenitor cells from which bone cells are formed and regulate the local cytokine environment to create a pro-osteogenic environment. Dysregulation of these cells is often seen in orthopaedic pathology and can be manipulated by the physician treating the patient. This narrative review aims to describe the common applications of cell therapies to bone healing whilst also suggesting the future direction of these techniques.

Nonunion Rate Following Primary Arthrodesis for Acute Lisfranc Injuries

Injury to the tarsometatarsal joint (TMT) results in instability throughout the midfoot that does not often improve with conservative management. If instability is identified, surgical intervention is frequently recommended, either open reduction and internal fixation (ORIF) or primary arthrodesis (PA). These 2 treatment options have been compared in the literature multiple times, often reporting similar outcomes. Due to this, as well as the need for subsequent hardware removal after ORIF has led many surgeons towards PA at the index surgery. Concern for nonunion is a leading concern with surgeons who advocate instead for ORIF. The purpose of this study is to review patients who underwent PA and observe nonunion rates. Nonunion at the TMT has been previously studied, but only in the chronic setting. We performed a retrospective study of 34 patients who had PA in the management of an acute Lisfranc injury. The average age in our study was 43.9 years old (range 19-72, SD 17.4) with an average follow-up of 9.4 months (range 4-33, SD 6.2). Radiographs were evaluated for signs of nonunion at regular postoperative intervals. Within the patients included in the study, a total of 71 TMT joints were fused. Overall successful fusion rate was 95.8% at an average of 7.9 weeks (range 6-12, SD 1.4) postoperatively. Individual nonunion rates at the first, second, and third TMT were 0%, 1.4% and 2.8% respectively. Our study demonstrates that primary arthrodesis provides a predictable outcome with low nonunion rates in the management of acute Lisfranc injury.

Usefulness of double plate fixation after failed ORIF for clavicle shaft fracture

PURPOSE

We aimed to evaluate the clinical and radiological outcomes of double plate fixation for failed clavicle shaft fracture surgery.

MATERIALS AND METHODS

We analyzed 14 patients who underwent double plate fixation due to plate failure after clavicle shaft fracture surgery from March 2016 to March 2021. The study used 3.5 mm locking compression plates for superior clavicle and anterior reconstruction in all patients. In addition, moldable allograft bone was used to fill the bone defect. Clinical and radiological evaluation was performed immediately, at 2 and 4 weeks, and 3, 6, 9, and 12 months postoperatively. The visual analog scale (VAS), University of California at Los Angeles (UCLA) shoulder scale, and American Shoulder and Elbow Surgeons (ASES) scores and range of motion of the shoulder were evaluated as clinical results. For radiological evaluation, anteroposterior, caudal, and cephalad views of both clavicles were used. Successful bone union was defined as complete adjoining of the fracture site through callus formation.

RESULTS

Successful bone union was achieved in all patients, and the mean time to bone union was 16.7 ± 1.2 weeks (range, 12-24 weeks). Statistically significant improvement in forward flexion and external and internal rotation was observed from 135.5° ± 6.3, 45.2° ± 5.3, and 13° ± 2.3 preoperatively to 157.0° ± 9.3, 68.7° ± 6.3, and 9.8° ± 3.1 at the final follow-up, respectively. The VAS score improved from an average of 6.2 ± 2.8 preoperatively to 1.3 ± 0.7 at the final follow-up, which was statistically significant (P = 0.018). In addition, the ASES score significantly increased from a mean of 52.1 ± 6.3 points preoperatively to 83.6 ± 7.8 points at the final follow-up (P = 0.001). The average UCLA shoulder score was 16.7 ± 1.4 and 31.4 ± 2.2 points preoperatively and at the final follow-up, respectively, which was statistically significant (P = 0.001).

CONCLUSION

Double plate fixation has shown good results after failed open reduction and internal fixation (ORIF) for clavicle shaft fractures. Therefore, in complicated situations after ORIF, double plate fixation is considered a surgical treatment option.

Development and validation of predictive nomogram for postoperative non-union of closed femoral shaft fracture

Closed femoral shaft fracture is caused by high-energy injuries, and non-union exists after operation, which can significantly damage patients' body and mind. This study aimed to explore the factors influencing postoperative non-union of closed femoral shaft fractures and establish a predictive nomogram. Patients with closed femoral shaft fractures treated at Hebei Medical University Third Hospital between January 2015 and December 2021 were retrospectively enrolled. A total of 729 patients met the inclusion criteria; of them, those treated in 2015-2019 comprised the training cohort (n = 617), while those treated in 2020-2021 comprised the external validation cohort (n = 112). According to multivariate logistic regression analysis, complex fractures, bone defects, smoking, and postoperative infection were independent risk factors. Based on the factors, a predictive nomogram was constructed and validated. The C-indices in training and external validation cohorts were 0.818 and 0.781, respectively; and the C-index of internal validation via bootstrap resampling was 0.804. The Hosmer-Lemeshow test showed good fit of the nomogram (P > 0.05) consistent with the calibration plot results. The clinical effectiveness was best at a threshold probability of 0.10-0.40 in decision curve analysis. The risk prediction for patients with fractures using this nomogram may aid targeted prevention and rehabilitation programs.

Bioinformatics Analysis and Experimental Validation of Differential Genes and Pathways in Bone Nonunions

Non-union fractures pose a significant clinical challenge, often leading to prolonged pain and disability. Understanding the molecular mechanisms underlying non-union fractures is crucial for developing effective therapeutic interventions. This study integrates bioinformatics analysis and experimental validation to unravel key genes and pathways associated with non-union fractures. We identified differentially expressed genes (DEGs) between non-union and fracture healing tissues using bioinformatics techniques. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analyses were employed to elucidate the biological processes and pathways involved. Common DEGs were identified, and a protein-protein interaction (PPI) network was constructed. Fibronectin-1 (FN1), Thrombospondin-1 (THBS1), and Biglycan (BGN) were pinpointed as critical target genes for non-union fracture treatment. Experimental validation involved alkaline phosphatase (ALP) and Alizarin Red staining to confirm osteogenic differentiation. Our analysis revealed significant alterations in pathways related to cell behavior, tissue regeneration, wound healing, infection, and immune responses in non-union fracture tissues. FN1, THBS1, and BGN were identified as key genes, with their upregulation indicating potential disruptions in the bone remodeling process. Experimental validation confirmed the induction of osteogenic differentiation. The study provides comprehensive insights into the molecular mechanisms of non-union fractures, emphasizing the pivotal roles of FN1, THBS1, and BGN in extracellular matrix dynamics and bone regeneration. The findings highlight potential therapeutic targets and pathways for further investigation. Future research should explore interactions between these genes, validate results using in vivo fracture models, and develop tailored treatment strategies for non-union fractures, promising significant advances in clinical management.

Advances with Platelet-Rich Plasma for Bone Healing

Despite significant advances in the understanding and delivery of osteosynthesis, fracture non-union remains a challenging clinical problem in orthopaedic surgery. To bridge the gap, basic science characterization of fracture healing provides a platform to identify and target biological strategies to enhance fracture healing. Of immense interest, Platelet-rich plasma (PRP) is a point of care orthobiologic that has been extensively studied in bone and soft tissue healing given its relative ease of translation from the benchtop to the clinic. The aim of this narrative review is to describe and relate pre-clinical in-vitro and in-vivo findings to clinical observations investigating the efficacy of PRP to enhance bone healing for primary fracture management and non-union treatment. A particular emphasis is placed on the heterogeneity of PRP preparation techniques, composition, activation strategies, and delivery. In the context of existing data, the routine use of PRP to enhance primary fracture healing and non-union management cannot be supported. However, it is acknowledged that extensive heterogeneity of PRP treatments in clinical studies adds obscurity; ultimately, refinement (and consensus) of PRP treatments for specific clinical indications, including repetition studies are warranted.

Novel approaches to correlate computerized tomography imaging of bone fracture callus to callus structural mechanics

Estimating the mechanical properties of bone in vivo without destructive testing would be useful for research and clinical orthopedic applications. Micro-computerized tomography (μCT) imaging can provide quantitative, high-resolution 3D representations of bone morphology and is generally the basis from which bone mechanical properties are non-destructively estimated. The goal of this study was to develop metrics using qualitative and quantitative aspects of bone microarchitecture derived from μCT imaging to estimate the mechanical integrity of bone fracture calluses. Mechanical testing data (peak torque) and μCT image data from 12 rat femur fractures were collected at 4 weeks after fracture. MATLAB was used to analyze the callus μCT imaging data which were then correlated to the empirically determined peak torque of the callus. One metric correlated Z-rays, linear contiguities of voxels running parallel to the neutral axis of the femur and through the fracture callus, to peak torque. Other metrics were based on voxel linkage values (LVs), which is a novel measurement defined by the number of voxels surrounding a given voxel (ranging from 1 to 27) that are all above a specified threshold. Linkage values were utilized to segment the callus and compute healing scores (termed eRUST) based on the modified Radiographic Union Score for Tibial fractures (mRUST). Linkage values were also used to calculate linked bone areas (LBAs). All metrics positively correlated with peak torque, yielding correlations of determination (R2) of 0.863 for eRUST, 0.792 for Z-ray scoring, and 0.764 for a normalized Linked Bone Area metric. These novel metrics appear to be promising approaches for extrapolating fracture callus structural properties from bone microarchitecture using objective analytical methods and without resorting to computationally complex finite element analyses.

Predictors requiring special attention to prevent clavicle fracture nonunion: a systematic review of literature

Background

Clavicle fracture (CF) is the tenth most prevalent fracture, accounting for an annual incidence of 37/10,000. This systematic review highlights the factors contributing to the nonunion union of the clavicular fracture.

Method

A systematic search was conducted using three web-based databases up to August 12, 2022, for conducting qualitative analysis. Articles were screened for relevance, and only studies that met inclusion criteria based on PECOS; P (patients): participants diagnosed with clavicular fracture; E (exposure): nonunion, C (control): not applicable; O (outcomes): factors contributing to nonunion or delayed union; S (studies): trials and observational studies. The Newcastle-Ottawa Scale was used to assess the quality of the cohort studies. The Cochrane risk of bias tool was used to assess the bias in randomized control trials.

Results

Ten studies were selected after the final literature search. Two thousand seven hundred and sixty-six adult participants who were radiologically and clinically diagnosed with nonunion clavicular fracture were included to pool the qualitative results. Fall was the most dominant cause of clavicular fracture, followed by road traffic collisions. Open reduction was widely used to treat nonunion correction. The qualitative results suggested a prominent correlation of nonunion with advancing age, female gender, high energy trauma, high Disabilities of the Arm, Shoulder, and Hand Score, smoking, fracture displacement, clavicular shortening, the callus on radiography, and fracture movement. The mid-shaft fracture was the most dominant type of fracture in the included studies; highly associated with nonunion in comparison to medial or lateral CF. The previous history of operation was an independent factor contributing to nonunion.

Conclusion

The results of this systematic review suggested the predictors contributing to nonunion in the CF. Demographic factors such as advancing age with female gender are at higher risk of developing clavicular nonunion. Smoking was the most dominantly highlighted environmental factor contributing to nonunion. Diaphyseal or midshaft fracture was the most common site for nonunion. Therefore, we suggested that patients with the predictors mentioned above require special attention to prevent nonunion of the CFs. More studies should be conducted on this subject to assess the factors that pose a risk associated with the nonunion of the bone for better clinical management and outcomes of the fracture.

Treatment of recalcitrant femur nonunion with pedicled corticoperiosteal medial femoral condyle flap

Periosteal or osteoperiosteal medial femoral condyle (MFC) flaps may be good options for atrophic nonunion. The aim of this study was to evaluate the effectiveness and safety of pedicled MFC flap in the treatment of recalcitrant femur nonunion without bone defect. Thirteen patients (11 male and 2 female), who suffered recalcitrant femur nonunion and were treated with pedicled osteoperiosteal MFC flap between January 2014 and April 2018, were included in this study. Patient files were reviewed retrospectively. Atrophic or recalcitrant 2/3 distal femoral nonunion were the indications for this clinical procedure. Demographics and operative data, flap size, visual analog scale (VAS) score, time to union, and complications were evaluated. A total of 13 patients underwent femur nonunion treatment with MFC flap after an average of 3.4 previous surgical procedures. The median age was 34 (Q1: 32.5, Q3:43) years old. The mean flap size was 4.3 × 6.4 cm, all nonunions healed in a median 5 months (Q1: 4.5, Q3: 6). There were an intraoperative knee medial collateral ligament injury in a patient, hematoma in a patient, and seroma in two patients. The median length of the follow-up was 40 months (Q1: 30, Q3: 47). There wasn't any additional complication in long-term follow-up. Functional outcomes were satisfactory. The median preoperative VAS score was 7 (Q1: 6, Q3: 9.5), decreasing to 1 (Q1: 0, Q3: 1) at the 6-month follow-up, and further reducing to 0 (Q1: 0, Q3: 1) at the 24-month follow-up. The nonunion period ranged from 6 to 18 months. The pedicled MFC flap is a good option for recalcitrant femur nonunion where larger vascularized flaps are not warranted. It is easy to harvest, does not require microvascular anastomosis, is effective, and offers minimal donor site morbidity.

A Murine Delayed-Healing Model Associates Immune Response with Functional Bone Regeneration after Trauma

Nonunion and delayed-union fractures pose a significant clinical challenge, often leading to prolonged morbidity and impaired quality of life. Fracture-induced hematoma and acute inflammation are crucial for establishing the healing cascade. However, aberrant inflammatory phenotypes can suppress healing and cause bone resorption. Elucidating these mechanisms is necessary to develop potent immunomodulatory therapies and prevent nonunion. Here, we report a delayed fracture healing model enabling the modulation of interfragmentary strain that mimics the etiology of hypertrophic nonunions to elucidate the role of dysregulated immune response in poor healing outcomes. High interfragmentary strain (>15%) was associated with larger callus volumes but delayed bone healing, increased inflammation, and inferior healing outcomes, while lower strain levels (<5%) corresponded to normal bone healing. In addition, we found distinct differences in the ossification, chondrification, and fibrosis patterns between high and low-strain groups, underscoring the significant impact of strain on the healing process. A comprehensive analysis of the systemic immune response revealed dynamic alterations in immune cell populations and factors, particularly within the early hours and days post-fracture. Several immune factors exhibited significant correlations with various functional healing outcomes, indicating their potential as predictive markers for assessing fracture healing progression. Our results also highlighted the significance of timely resolution of proinflammatory signals and the elevation of pro-regenerative immune cell phenotypes in promoting bone regeneration. Multivariate analysis revealed that CD25+ T-regulatory cells were influential in predicting proper bone healing, followed by CD206+ macrophages, underscoring the pivotal role of immune cell populations in the bone healing process. In conclusion, our study provides valuable insights into the intricate interplay between interfragmentary strain, immune response, and the ultimate outcomes of fracture healing. By shedding light on the underlying mechanisms that drive hypertrophic nonunion pathogenesis, our research lays the foundation for enhanced surgical management of nonunions and offers a promising avenue for developing targeted therapeutic interventions and personalized treatment strategies for individuals suffering from fracture nonunion.

Use of locked plates and mono-rail fixator in segmental tibial defects: A prospective interventional study

Introduction

The management of gap non-union is a major challenge to both the clinician and the patient as it is technically difficult, time-intensive, and physically arduous for the patient along with an unpredictable result. Gap non-union can arise from extrusion of bony fragment at the time of trauma or after debridement of unhealthy bone later. Moreover, Tibia because of its subcutaneous anatomy can easily undergo bone-loss and segmental defect. Among various methods available for managing gap non-union of tibia distraction osteogenesis using either ilizarov fixator or mono-rail fixator is the most popular one. Here we present functional and bony outcomes of combined use of locking plate and Limb Reconstruction System (LRS) in tibial gap non-union and assess whether it decreases fixator time and related complications.

Patients and methods

A prospective intervention study constituting 10 patients with Paley's type B1 tibial gap non-union over a period of 22months. In first stage, debridement was done; tibial locking plate and mono-rail fixator were applied along with corticomy at proximal tibia. Distraction was started 7-14 days later. At the end of distraction phase, fixator was removed and transported segment was fixed with screws with or without bone grafting at docking site. Patients were followed up every 6 weeks for radiological and clinical assessment. Functional assessment using Application for the Study and Application of the Method of Ilizarov (ASAMI) functional score, and Musculoskeletal Tumour Society (MSTS) functional score while bone outcome was assessed with ASAMI bone score. Quality of regenerate was assessed by Fernandez-Esteve grading. Detailed scoring was done at the time of index surgery, at the time of LRS removal and at the time of consolidation phase.

Results

All the 10 patients were male with mean age of 33 years. The mean defect size was 4.94 cm after debridement. Minimum duration of follow up was 30 weeks after removal of LRS. Mean duration between trauma and inclusion in the study was 17.7 months. The median external fixator index was 15.63 days/cm. The complication rate was 1.3/patient. According to Paley's classification, there were eleven problems and two obstacles, and no true complications. Both ASAMI bone score and functional scores were excellent in three and good in six patients. The median MSTS composite score was 76.66%.

Conclusion

The integrated fixation is an effective and satisfactory method enabling early external fixator removal with low rate of complication. So, this technique can be recommended for the management of segmental tibial defects.

Level of evidence

II.

Universal Long Bone Nonunion Classification

Aim and background

The management of bone union disorders is a complex problem in orthopaedics, requiring a reliable and comprehensive classification system for accurate diagnosis and treatment. Despite advances in understanding pathophysiology, diagnosis, and treatment in this area, there is no generally accepted classification system. The aim of our work was to create a comprehensive classification, which will systemize the vast majority of bone union disorders, underline their differences and form the basis for their treatment.

Methods

The key criteria for nonunion evaluation and treatment were identified based on the conducted literature review: Time from the initial event (delayed union or nonunion), location, type of pathology (A, Hypertrophic; B, Normotrophic; C, Oligotrophic) and the presence of hardware. Based on these criteria the ULBNC has been developed. Atrophic nonunions were excluded from this classification as they are considered segmental bone defects with special classification.

Results

The ULBNC is based on the same principles of coding as the "gold standard" AO/OTA Fractures Classification system with alpha-numeric coding "from simple to complex." The choice of treatment method depends on the type, group, and subgroup of the nonunion as described.

Conclusion

Universal Long Bone Nonunion Classification (ULBNC) is an alphanumeric system that describes the localization, type of pathology and morphologic characteristics of a nonunion. The use of ULBNC in practice and research will optimize and standardize the treatment of various types of bone healing disorders and eventually improve clinical outcomes.

How to cite this article

Solomin LN, Semenistyy AA, Komarov AV, et al. Universal Long Bone Nonunion Classification. Strategies Trauma Limb Reconstr 2023;18(3):169-173.

Outcomes After Acute Versus Delayed Total Elbow Arthroplasty for the Treatment of Distal Humerus Fractures

Purpose

Compare outcomes of acute versus delayed total elbow arthroplasty (TEA) following distal humerus fractures (DHF).

Methods

This retrospective study included 39 patients who underwent primary TEA with semiconstrained implants for DHF, either within 4 weeks of their injury or after failing initial open reduction and internal fixation (ORIF) or nonsurgical management, between June 1, 2003 and February 1, 2018 with minimum 1-year follow-up. Our outcome measures included QuickDASH (Disabilities of the Arm, Shoulder, and Hand) score, complications, reoperations, and range of motion (ROM). Demographics, clinical variables, and outcomes were compared using the Student's t-test, Mann-Whitney U test, and Fisher's exact test as appropriate. Kaplan-Meier curves for mortality, implant survivorship, and reoperation were created.

Results

Our patients were categorized into acute TEA (n = 22), ORIF to TEA (n = 10), and nonsurgical to TEA (n = 7) treatment groups. Additional analysis was performed comparing acute to delayed TEA, which combined data from failed ORIF and nonsurgical cohorts. The median follow-up, average age, and median Charlson comorbility index were similar between groups. The most common fracture pattern was AO13C. At median follow-up of 5.8 years, QuickDASH differed between cohorts: mean of 31 (SD 19) in acute TEA and 52 (SD 27) in delayed TEA, which further subdivided to 44.2 (SD 25) in failed ORIF and 76 (SD 23) in failed nonsurgical management. Poorer QuickDASH scores at final follow-up were associated with delayed TEA, initial nonsurgical management, and depression. Surgical complications were associated with delayed TEA. Higher Charlson comorbidity index was associated with death. No variables were associated significantly with ROM, revision, or reoperation.

Conclusion

Comminuted DHFs are difficult to treat in the elderly with high rates of complication and poor function after surgery. Our study suggests TEA performed acutely result in satisfactory outcomes and should be a consideration for patients at high risk of failing ORIF or nonsurgical management.

Type of Study/Level of Evidence

Therapeutic, III.

Dual-Energy CT-based Opportunistic Volumetric Bone Mineral Density Assessment of the Distal Radius

Background In patients with distal radius fractures (DRFs), low bone mineral density (BMD) is associated with bone substitute use during surgery and bone nonunion, but BMD information is not regularly available. Purpose To evaluate the feasibility of dual-energy CT (DECT)-based BMD assessment from routine examinations in the distal radius and the relationship between the obtained BMD values, the occurrence of DRFs, bone nonunion, and use of surgical bone substitute. Materials and Methods Scans in patients who underwent routine dual-source DECT in the distal radius between January 2016 and December 2021 were retrospectively acquired. Phantomless BMD assessment was performed using the delineated trabecular bone of a nonfractured segment of the distal radius and both DECT image series. CT images and health records were examined to determine fracture severity, surgical management, and the occurrence of bone nonunion. Associations of BMD with the occurrence of DRFs, bone nonunion, and bone substitute use at surgical treatment were examined with generalized additive models and receiver operating characteristic analysis. Results This study included 263 patients (median age, 52 years; IQR, 36-64 years; 132 female patients), of whom 192 were diagnosed with fractures. Mean volumetric BMD was lower in patients who sustained a DRF (93.9 mg/cm3 vs 135.4 mg/cm3; P < .001), required bone substitutes (79.6 mg/cm3 vs 95.5 mg/cm3; P < .001), and developed bone nonunion (71.1 mg/cm3 vs 96.5 mg/cm3; P < .001). Receiver operating characteristic curve analysis identified these patients with an area under the curve of 0.71-0.91 (P < .001). Lower BMD increased the risk to sustain DRFs, develop bone nonunion, and receive bone substitutes at surgery (P < .001). Conclusion DECT-based BMD assessment at routine examinations is feasible and could help predict surgical bone substitute use and the occurrence of bone nonunion in patients with DRFs. © RSNA, 2023 Supplemental material is available for this article. See also the editorial by Carrino in this issue.

The Impact of Surgical Timing After Ankle Fracture on Clinical and Long-Term Patient Reported Outcomes

The goal of this study is to evaluate the effect of time-to-surgery following closed ankle fractures on long-term patient reported outcomes, fracture healing, and wound complications. To date, little research has been done focusing on the impact "time to definitive fixation" has on patient reported outcomes. We performed a retrospective analysis of 215 patient records who underwent open reduction and internal fixation (ORIF) for an ankle fracture from July 2011 to July 2018. A total of 86 patients completed the patient reported outcome measurement information systems (PROMIS) survey at long-term follow-up. Primary outcomes were the rate of delayed union, postoperative wound complications, patient reported outcome measurement information system (PROMIS) pain interference (PI), and physical function (PF) scores. No differences were found when comparing time to surgery on a continuous scale with rates of delayed union, nonunion, or wound complications (p = .84, .47, and .63, respectively). PROMIS scores were collected at a median of 4.5 years (2.0 interquartile range (IQR), range 2.5-12.3) postoperatively. The time from ankle fracture to surgery was independently associated with worse PROMIS PI scores (unstandardized β 0.38, 95% CI 0.07-0.68) but not PROMIS PF scores. Severe Lauge-Hansen injuries were independently associated with decreased PROMIS PF scores (unstandardized β -7.02, 95% CI -12.0 to -2.04). Increased time to surgical intervention and severe Lauge-Hansen injuries were independently associated with worse long-term patient reported outcomes. Surgical timing did not impact union rates or wound complications. Surgeons should be aware that delaying ankle fracture repair beyond 12 days after injury may negatively affect long-term patient reported pain scores.

Return to sport after forearm fractures in children: A scoping review and survey

Purpose

A common question faced by clinicians is when a child may return to sport after treatment for a pediatric forearm fracture. There are few published recommendations and fewer supported by evidence. The aims of this study were to summarize existing published recommendation for return to sport after pediatric forearm fractures and to conduct a survey to determine usual clinical recommendations.

Methods

A scoping review was performed on Ovid MEDLINE, Cochrane Central Register of Controlled Trials, Embase, Scopus, and Google Scholar in accordance with the Joanna Briggs Institute guidelines. In addition, 64 orthopedic surgeons were anonymously surveyed asking for recommendations regarding return to sport after pediatric forearm fractures. Participants were to assume children were 9 years old and played a sport with an average risk of forearm injury.

Results

Twenty-two publications for return to sport were retrieved. Children with distal radius buckle fractures safely commonly returned to sport by 4 weeks after initial injury, while survey respondents recommended over 6 weeks. Survey respondents valued fracture stability the highest when making return to sport recommendations. Children with simple, metaphyseal, single-bone fractures were usually allowed to return to sport at 8-10 weeks post-injury. Diaphyseal and complete fractures were prescribed longer return to sport intervals. Australian respondents also prescribed longer return to sport intervals.

Conclusion

Children with distal radius buckle fractures may return to sport by 4 weeks after initial injury, sooner than recommended. Published recommendations remain limited for other fractures. However, our survey suggests children with simple, metaphyseal, single-bone fractures may return to sport at 8-10 weeks. Children with diaphyseal and complete fractures should abstain from sport for longer than metaphyseal and greenstick fractures, respectively.

Level of evidence

level V.

Management of Traumatic Femur Fractures: A Focus on the Time to Intramedullary Nailing and Clinical Outcomes

Background: Femur shaft factures (FSF) are common injuries following high-energy mechanisms mainly involving motor vehicle crashes (MVC). We evaluated the timings of nailing management and analyzed the pattern of fracture union and outcome in a level 1 trauma center. Methods: This was a retrospective observational study of all the admitted trauma patients who sustained femoral fractures between January 2016 and September 2020. Data were analyzed and compared based on time to Intramedullary Nailing (IMN) (<12 h, 12–24 h and >24 h) and outcomes of FSF (union, delayed union and nonunion). Results: A total of 668 eligible patients were included in the study, of which the majority were males (90.9%) with a mean age of 34.5 ± 15.8, and 54% of the injuries were due to MVCs. The chest (35.8%) was the most commonly associated injured body region, followed by the pelvis (25.9%) and spine (25.4%). Most of femur fractures (93.3%) were unilateral, and 84.4% were closed fractures. The complete union of fractures was observed in 76.8% of cases, whereas only 4.2% and 3.3% cases had delayed union and nonunion, respectively, on the clinical follow-up. Patients in the delayed IMN (>24 h) were severely injured, had bilateral femur fracture (p = 0.001) and had higher rate of external fixation, blood transfusion, pulmonary complications and prolonged hospitalization. Non-union proportion was greater in those who had IMN <24 h, whereas a delayed union was greater in IMN done after 24 h (p = 0.5). Those with a nonunion femur fracture were more likely to have bilateral fracture (p = 0.003), frequently had retrograde nailing (p = 0.01), and high-grade femur fracture (AO type C; p = 0.04). Conclusion: This study showed that femur fracture is not uncommon (8.9%), which is manifested with the variety of clinical characteristics, depending on the mechanism, management and outcome in our center. Bilateral fracture, retrograde nailing and AO classification type C were the significant risk factors of non-union in patients with diaphyseal fractures. The timing of IMN has an impact on the fracture union; however, it is not a statistically significant difference. Therefore, the treating physicians should consider the potential risk factors for a better outcome by careful selection of treatment in sub-groups of patients.

Use of Teriparatide in preventing delayed bone healing and nonunion: a multicentric study on a series of 20 patients

BACKGROUND

Delayed bone healing and nonunions represent a great challenge for the orthopedic surgeon. In addition to traditional surgical approaches, increasing attention is being given to the use of systemic anabolic therapy with Teriparatide, whose efficacy in preventing osteoporotic fractures is widely validated and whose application as a promoter of bone healing has been described but it is still debated. The aim of the study was to evaluate bone healing in a series of patients with delayed unions or nonunions treated with Teriparatide in conjunction with eventual appropriate surgical procedure.

METHODS

Twenty patients with an unconsolidated fracture that were treated at our Institutions from 2011 to 2020 with Teriparatide were retrospectively included into the study. The pharmacological anabolic support was used off-label with a planned duration of 6 months; radiographic healing was evaluated at 1-, 3- and 6-months follow-up outpatient visits over plain radiographs. Also, eventual side-effects were registered.

RESULTS

Radiographic signs indicative of favorable evolution of the bone callus were observed as early as at 1 month of therapy in 15% of cases; at 3 months, healing progression was appreciated in 80% of cases and complete healing in 10%; at 6 months, 85% of delayed and nonunions had healed. In all patients, the anabolic therapy was well tolerated.

CONCLUSIONS

In accordance to Literature, this study suggests that Teriparatide plays a potentially important role in the treatment of some forms of delayed unions or nou-nions, even in the presence of failure of hardware. The results suggest a greater effect of the drug when associated with a condition in which the bone is in an active phase of callogenesis, or with a "revitalizing" treatment which represents a local (mechanical and/or biological) stimulus to the healing process. Despite the small sample size and the variety of cases, the efficacy of Teriparatide in treating delayed unions or nonunions emerged, highlighting how this anabolic therapy can represent a useful pharmacological support in the treatment of such a pathology. Although the results obtained are encouraging, further studies, particularly prospective and randomized, are needed to confirm the efficacy of the drug, and define a specific treatment algorithm.

Clinical and Radiological Outcomes of Gustilo-Anderson Type IIIB Open Fractures in 125 Patients

INTRODUCTION

This study describes single-centre outcomes of Gustilo-Anderson type IIIB open fractures in relation to the current standards in the United Kingdom, which aim at performing skeletal fixation and soft tissue coverage at an early stage to salvage the limb and achieve bone union with a minimum infection rate.

METHODS

A total of 125 patients with 134 Gustilo-Anderson type IIIB open fractures, who had definitive skeletal fixation with soft tissue coverage between June 2013 and October 2021, were prospectively followed up and included in this study.

RESULTS

Initial debridement was performed within 12 hours from the time of injury for 62 (49.6%) patients and within 24 hours for 119 (95.2%) patients (mean= 12.4 hours). Definitive skeletal fixation and soft tissue coverage were achieved within 72 hours for 25 (20%) patients and within seven days for 71 (57%) patients (mean= 8.5 days). The mean follow-up duration was 43.3 (6-100) months, and the limb salvage rate was 97.1%. The occurrence of deep infections was associated with time from injury to initial debridement (p=0.049). Three patients (2.4%) developed deep (metalwork) infections, all three had their initial debridement performed within 12 hours from the time of injury. There was no association between time to definitive surgery and the development of deep infection (p=0.340). Bone union was achieved in 84.3% of patients following their primary surgery. Time to union was associated with fixation modality (p=0.002) and type of soft tissue coverage (p=0.028), and was negatively correlated with time to initial debridement (p=0.002, correlation coefficient -0.321). There was a 0.27-month decrease in time to union for every hour delay in time to debridement (p=0.021).

CONCLUSION

Delaying initial debridement or definitive fixation and soft tissue coverage didn't increase the rate of deep (metalwork) infections. The time to achieve bone union was negatively correlated with the time from injury to initial debridement. We advise prioritising surgical technique and availability of expertise over strict adherence to time thresholds of surgeries.

The Impact of Smoking on Delayed Osseous Union After Arthrodesis Procedures in the Hand and Wrist

PURPOSE

The purpose of this study was to evaluate the relationship between smoking and delayed radiographic union after hand and wrist arthrodesis procedures. We hypothesized that smoking would be associated with a higher rate of delayed union.

METHODS

All cases of hand or wrist arthrodesis procedures in patients aged ≥18 years from 2006 to 2020 were identified. Cases were included if they had >90 days of radiographic follow-up or evidence of union before 90 days. Baseline demographics were recorded for each case including smoking status at the time of surgery. Complications were recorded and all postoperative radiographs were reviewed to assess for evidence of delayed union (defined as lack of osseous union by 90 days after surgery). We compared active smokers and nonsmokers and performed a logistic regression analysis to estimate the odds of experiencing a delayed radiographic union.

RESULTS

A total of 309 arthrodesis cases were included and 24% were active smokers. Overall, radiographic evidence of a delayed union was found in 17% of cases. Smokers were significantly more likely to have a delayed union compared with nonsmokers (27% vs 14%). Results of the adjusted logistic regression analysis demonstrated that there was a significantly increased odds of experiencing a delayed union for patients who were active smokers compared with nonsmokers (odds ratio, 2.20; 95% confidence interval, 1.09-4.43). In addition, the rate of symptomatic nonunion requiring reoperation was higher in smokers (15%) compared with nonsmokers (6%).

CONCLUSIONS

Smoking was associated with increased odds of delayed radiographic union in patients undergoing hand and wrist arthrodesis procedures. Patients should be counseled appropriately on the risks of smoking on bone healing and encouraged to abstain from nicotine use in the perioperative period.

TYPE OF STUDY/LEVEL OF EVIDENCE

Prognostic II.

Non-union of Conservatively Managed Radial Neck Fractures in Adults: A Systematic Review

Non-union of radial neck fractures in adults is rare. This review aims to identify factors contributing to the non-union of undisplaced radial neck fractures and assess treatment options and outcomes.

Systematic searches of English articles in PubMed, Embase, Ovid Medline, Cochrane Central Register of Controlled Trials, and Cochrane Database of Systematic Reviews were undertaken in September 2021 according to the PRISMA guidelines. The search terms were (fracture) AND (radial neck) AND (non-union OR non-union). Eligible studies reported adults who experienced undisplaced radial neck fractures that went on to non-union without prior surgical intervention.

Fifteen case reports/series were included involving 29 non-unions in 27 patients. The largest study included eight patients. There were 11 males (38%) and 18 females (62%). The average age at the time of the presentation was 55 (range: 29-73). In 13 cases, comorbidities were commented on, including association with smoking in 4 (30%), diabetes in 3 (23%), and excessive alcohol in 5 (38%). The average time from injury to a diagnosis of non-union was 6.7 (range: 2-24) months. The average time of follow-up was 28.6 (range:6-84) months. Eight minimally symptomatic or asymptomatic non-unions were managed conservatively without complication. Seventeen symptomatic non-unions were managed operatively. Treatments included open fixation (1), open fixation with bone grafting (1), bone grafting alone (2), arthroplasty (2), radial head resection (2), and unknown surgery (7). Patients managed operatively achieved full or near-full, asymptomatic range of motion at an average of 5.4 (3-12) months postoperatively.

Non-union is a rare complication of an adult radial neck fracture, and risk factors may include female gender, smoking, diabetes, and chronic alcohol. Persistence with non-operative management is encouraged as it can resolve symptoms with or without a radiographic union. Operative options range from bone grafting +/- fixation to arthroplasty. On average, the time from injury to the decision made to operate is 6.5 (3-12) months. A comfortable, functional range of motion is possible with all treatment strategies.

Injectable nanoporous microgels generate vascularized constructs and support bone regeneration in critical-sized defects

Large and aberrant bone fractures require ossification and concomitant vascularization for proper healing. Evidence indicates that osteogenesis and vessel growth are coupled in bone fractures. Although the synergistic role of endothelial cells has been recognized, vascularizing large bone grafts remains a challenge and has apprehended the clinical translation of engineered bone constructs. Here, we describe a facile method to fabricate vascularized constructs using chitosan and gelatin-based microgels that promote osteogenesis of human mesenchymal stromal cells (MSC) while supporting endothelial sprouting and network formation. The microgels are enzymatically degradable and had a high hydration rate with a volume swelling ratio of ~ 493% and a polymer density of ~ 431 mg/cm3, which is comparable to that of native skeletal tissues. AFM indentation of the surface showed an average Young's modulus of 189 kPa, falling in a range that is conducive to both osteogenesis and vasculogenesis. The osteogenic microgel containing chitosan, gelatin, and hydroxyapatite, mimicking the bone matrix, supported robust attachment, proliferation, and differentiation of MSC. On the other hand, the vasculogenic microgels containing only gelatin, enriched endothelial phenotype and enabled vascular networks formation when embedded in 3D matrices. Combining the two types of microgels created a hybrid construct that sustained the functions of both osteogenic and vasculogenic microgels and enhanced one another. Using a murine model, we also show that the osteogenic microgels regenerate bone in a critical-sized defect with > 95% defect closure by week 12. These multifunctional microgels can be administered minimally invasively and can conformally fill large bone defects. This work lays the foundation to establish principles of designing multiphasic scaffolds with tissue-specific biophysical and biochemical properties for regenerating vascularized and interfacial tissues.

Medial oblique malleolar osteotomy for approach of medial osteochondral lesion of the talus

PURPOSE

The medial malleolar osteotomy is commonly performed to gain access to the medial talar dome for treatment of osteochondral lesions of the talus. The primary aim of this study was to assess osseous healing based on postoperative radiographs to determine consolidation, non-union and malreduction rates.

METHODS

Sixty-seven cases were reviewed where an oblique uniplanar medial malleolar osteotomy was performed to gain access to the medial talar dome for addressing an osteochondral lesion. Two, respectively three fully threaded 3.5 mm corticalis screws were used to fixate the osteotomy. Postoperative radiographs were reviewed to assess consolidation, non-union, malreduction and dislocation of the osteotomy.

RESULTS

Out of 67 patients, 66 patients had a consolidation of the osteotomy. 23.9% of the cases showed malreduction of the osteotomy. One patient suffered a non-union, which required a revision surgery. No significant difference was shown between two and three screws used for fixation in terms of malreduction and consolidation of the osteotomy. Eighty-four percent of the patients underwent hardware removal due to pain or medial impingement.

CONCLUSION

The oblique medial malleolar osteotomy is a safe and relatively simple procedure with a high consolidation rate and low revision providing excellent exposure of the talus. The moderately high malreduction rate and required hardware removal surgery by most of the patients are relevant factors which should be considered before performing this surgery.

LEVEL OF EVIDENCE

Level III, retrospective cohort study.

Reactive sulfur and selenium species in the regulation of bone homeostasis

Reactive oxygen species (ROS) are important modulators of physiological signaling and play important roles in bone tissue regulation. Both reactive sulfur species (RSS) and reactive selenium species (RSeS) are involved in ROS signaling, and recent work suggests RSS and RSeS involvement in the regulation of bone homeostasis. For example, RSS can promote osteogenic differentiation and decrease osteoclast activity and differentiation, and the antioxidant activity of RSeS play crucial roles in balancing bone remodeling. Here, we outline current research progress on the application of RSS and RSeS in bone disease and regeneration. Focusing on these investigations, we highlight different methods, tools, and sources of RSS and RSeS, and we also highlight future opportunities for delivery of RSS and RSeS in biological environments relating to bone.

Wireless Measurements Using Electrical Impedance Spectroscopy to Monitor Fracture Healing

There is an unmet need for improved, clinically relevant methods to longitudinally quantify bone healing during fracture care. Here we develop a smart bone plate to wirelessly monitor healing utilizing electrical impedance spectroscopy (EIS) to provide real-time data on tissue composition within the fracture callus. To validate our technology, we created a 1-mm rabbit tibial defect and fixed the bone with a standard veterinary plate modified with a custom-designed housing that included two impedance sensors capable of wireless transmission. Impedance magnitude and phase measurements were transmitted every 48 h for up to 10 weeks. Bone healing was assessed by X-ray, µCT, and histology. Our results indicated the sensors successfully incorporated into the fracture callus and did not impede repair. Electrical impedance, resistance, and reactance increased steadily from weeks 3 to 7-corresponding to the transition from hematoma to cartilage to bone within the fracture gap-then plateaued as the bone began to consolidate. These three electrical readings significantly correlated with traditional measurements of bone healing and successfully distinguished between union and not-healed fractures, with the strongest relationship found with impedance magnitude. These results suggest that our EIS smart bone plate can provide continuous and highly sensitive quantitative tissue measurements throughout the course of fracture healing to better guide personalized clinical care.

Is Atrophic Nonunion a Misnomer - A Hospital-based Prospective Cross-Sectional Study

Objective  The present study was conducted to estimate histologically the proportion of avascularity of fracture ends in case of nonunion of long bones. Methods  A total of 15 cases of established quiescent nonunion were operated according to the standard protocol and the fracture ends were evaluated histologically. The biopsied tissue was briefly fixed with formalin, embedded with paraffin (FFPE), and 5-micron sections were stained with hematoxylin and eosin according to standard protocols. Immunohistochemistry with anti-CD31 antibody (JC70A clone, DBS) was performed manually using standard protocols. Results  All cases of quiescent nonunion were included; radiologically, 2 cases were oligotrophic, and 13 cases were of atrophic nonunion. A total of 20% of the patients were females, 40% were in the age group between 31and 40 years old, and, radiologically, all cases were of atrophic nonunion. All cases showed positivity for CD-31 on immunohistochemistry. The blood vessel density was category I in 13.33% of the cases and category II in 86.67% of the cases. Four cases presented with mild inflammation and two presented with moderate inflammation. The average vessel count was 10 per high power field in the age groups between 20 and 30, 31 and 40, and 41and 50 years old. The age group between 61 and 70 years old showed an average vessel count of 4 per high power field. The difference in the vessel counts of oligotrophic and atrophic nonunion was not significant. No correlation was observed in the density of vessel count and duration of nonunion Conclusion  The nomenclature for the classification of nonunion into atrophic, oligotrophic, and hypertrophic needs revision. Our findings do not support that atrophic and oligotrophic nonunion are histologically different.

Cortical allograft strut augmented with platelet-rich plasma for the treatment of long bone non-union in lower limb- a pilot study

Background

The autogenous iliac bone graft is the first choice of surgical treatment for long bone non-union. However, many factors limit the use of autogenous bone, such as insufficient bone harvest and complications in the donor site. This study aimed to pilot-test the effectiveness of the cortical allograft strut augmented with Platelet-rich plasma (PRP) on long bone non-union in the lower limb.

Method

This study was a one-armed pilot trial, with thirteen men and four women patients scheduled for surgery. Revision surgery for managing long bone non-union included debridement, internal fixation of the cortical allograft strut, and adding PRP in the fracture site. After surgery, outcome measurements of healing rate, healing time, the incidence of revision, and complications, were assessed at least one-year follow-up.

Results

Fourteen of seventeen participants completed all follow-ups. The mean age of 14 patients was 35.9 years (range, 18–56 years), and the mean BMI was 22.44 ± 1.53 kg/m². All nonunions united after the operation. The mean healing time was 4.6 ± 0.7 months. There was no revision or complication.

Conclusion

Cortical allograft strut augmented with PRP led to healing long bone non-union in the lower limb. More clinical research is required before widespread use.

Outcomes of the Treatment of Fracture Non-union Using Combined Magnetic Field Bone Growth Stimulation: Experiences From a UK Trauma Unit

Introduction: Fracture non-union is a distressing diagnosis for both patients and clinicians. Several methods have been tried to help promote bone healing. Some of the non-operative strategies include the use of pulsed ultrasound and electrical or magnetic bone stimulators. This study aimed at assessing the outcomes of patients treated with combined magnetic field (CMF) bone stimulators.

Methods: All patients with confirmed fracture non-union treated using a CMF bone growth stimulator between May 2019 and December 2021 were included in the study. These were followed up at regular three-month intervals and monitored for signs of clinical and radiological union. The minimum patient follow-up was six months. Our primary outcome measure was union rates following CMF treatment. The secondary outcome measures were time to union and fracture type/configuration in relation to non-union.

Results: A total of 29 patients were included. Of the patients, 52% were female. The average age of the patients was 53.42 years (SD: 17.66 years). Four were excluded because their follow-up period was less than six months. Patients were started on CMF bone growth stimulant treatment between four and 27 months from the initial fracture (mean: 11.56 months). The majority of the patients had tibial shaft (21%), distal femur (17%), ankle (10%) and distal humerus (10%) fractures. The overall success rate was 84% (n=21), with a mean time to union of 6.62 months.

Conclusion: Bone growth stimulators using combined magnetic fields are a viable treatment option for established fracture non-union. They can result in improved outcomes and can avoid risks and costs associated with surgical options to treat non-union. However, more studies need to be conducted to establish the efficacy of these methods conclusively.

Cryogel Scaffold-Mediated Delivery of Adipose-Derived Stem Cells Promotes Healing in Murine Model of Atrophic Non-Union

Non-union is defined as the permanent failure of a bone to heal and occurs clinically in 5% of fractures. Atrophic non-unions, characterized by absent/minimal callus formation, are poorly understood and difficult to treat. We recently demonstrated a novel murine model of atrophic non-union in the 3.6Col1A1-tk (Col1-tk) mouse, wherein dosing with the nucleoside analog ganciclovir (GCV) was used to deplete proliferating osteoprogenitor cells, leading to a radiographic and biomechanical non-union after the mid-shaft femur fracture. Using this Col1-tk atrophic non-union model, we hypothesized that the scaffold-mediated lentiviral delivery of doxycycline-inducible BMP-2 transgenes would induce osteogenesis at the fracture site. Cryogel scaffolds were used as a vehicle for GFP+ and BMP-2+ cell delivery to the site of non-union. Cryogel scaffolds were biofabricated through the cross-linking of a chitosan-gelatin polymer solution at subzero temperatures, which results in a macroporous, spongy structure that may be advantageous for a bone regeneration application. Murine adipose-derived stem cells were seeded onto the cryogel scaffolds, where they underwent lentiviral transduction. Following the establishment of atrophic non-unions in the femurs of Col1-tk mice (4 weeks post-fracture), transduced, seeded scaffolds were surgically placed around the site of non-union, and the animals were given doxycycline water to induce BMP-2 production. Controls included GFP+ cells on the cryogel scaffolds, acellular scaffolds, and sham (no scaffold). Weekly radiographs were taken, and endpoint analysis included micro-CT and histological staining. After 2 weeks of implantation, the BMP-2+ scaffolds were infiltrated with cartilage and woven bone at the non-union site, while GFP+ scaffolds had woven bone formation. Later, timepoints of 8 weeks had woven bone and vessel formation within the BMP-2+ and GFP + scaffolds with cortical bridging of the original fracture site in both groups. Overall, the cell-seeded cryogels promoted osseous healing. However, while the addition of BMP-2 promoted the endochondral ossification, it may provide a slower route to healing. This proof-of-concept study demonstrates the potential for cellularized cryogel scaffolds to enhance the healing of non-unions.

Reliability of Modified Radiographic Union Score for Tibia Scores in the Evaluation of Femoral Shaft Fractures in a Low-resource Setting

INTRODUCTION

The modified Radiographic Union Score for Tibia (RUST) fractures was developed to better describe fracture healing, but its utility in resource-limited settings is poorly understood. This study aimed to determine the validity of mRUST scores in evaluating fracture healing in diaphyseal femur fractures treated operatively at a single tertiary referral hospital in Tanzania.

METHODS

Radiographs of 297 fractures were evaluated using the mRUST score and compared with outcomes including revision surgery and EuroQol five dimensions questionnaire (EQ-5D) and visual analog scale (VAS) quality-of-life measures. Convergent validity was assessed by correlating mRUST scores with EQ-5D and VAS scores. Divergent validity was assessed by comparing mRUST scores in patients based on revision surgery status.

RESULTS

The mRUST score had moderate correlation (Spearman correlation coefficient 0.40) with EQ-5D scores and weak correlation (Spearman correlation coefficient 0.320) with VAS scores. Compared with patients who required revision surgery, patients who did not require revision surgery had higher RUST scores at all time points, with statistically significant differences at 3 months (2.02, P < 0.05).

DISCUSSION

These results demonstrate that the mRUST score is a valid method of evaluating the healing of femoral shaft fractures in resource-limited settings, with high interrater reliability, correlation with widely used quality of life measures (EQ-5D and VAS), and expected divergence in the setting of complications requiring revision surgery.

Animal models of impaired long bone healing and tissue engineering- and cell-based in vivo interventions

Bone healing after injury typically follows a systematic process and occurs spontaneously under appropriate physiological conditions. However, impaired long bone healing is still quite common and may require surgical intervention. Various complications can result in different forms of impaired bone healing including nonunion, critical-size defects, or stress fractures. While a nonunion may occur due to impaired biological signaling and/or mechanical instability, a critical-size defect exhibits extensive bone loss that will not spontaneously heal. Comparatively, a stress fracture occurs from repetitive forces and results in a non-healing crack or break in the bone. Clinical standards of treatment vary between these bone defects due to their pathological differences. The use of appropriate animal models for modeling healing defects is critical to improve current treatment methods and develop novel rescue therapies. This review provides an overview of these clinical bone healing impairments and current animal models available to study the defects in vivo. The techniques used to create these models are compared, along with the outcomes, to clarify limitations and future objectives. Finally, rescue techniques focused on tissue engineering and cell-based therapies currently applied in animal models are specifically discussed to analyze their ability to initiate healing at the defect site, providing information regarding potential future therapies. In summary, this review focuses on the current animal models of nonunion, critical-size defects, and stress fractures, as well as interventions that have been tested in vivo to provide an overview of the clinical potential and future directions for improving bone healing.

Bone turnover markers as surrogates of fracture healing after intramedullary fixation of tibia and femur fractures

Aims

Bone turnover markers (BTMs) follow distinct trends after fractures and limited evidence suggests differential levels in BTMs in patients with delayed healing. The effect of vitamin D, and other factors that influence BTMs and fracture healing, is important to elucidate the use of BTMs as surrogates of fracture healing. We sought to determine whether BTMs can be used as early markers of delayed fracture healing, and the effect of vitamin D on BTM response after fracture.

Methods

A total of 102 participants aged 18 to 50 years (median 28 years (interquartile range 23 to 35)), receiving an intramedullary nail for a tibial or femoral shaft fracture, were enrolled in a randomized controlled trial comparing vitamin D₃ supplementation to placebo. Serum C-terminal telopeptide of type I collagen (CTX; bone resorption marker) and N-terminal propeptide of type I procollagen (P1NP; bone formation marker) were measured at baseline, six weeks, and 12 weeks post-injury. Clinical and radiological fracture healing was assessed at three months.

Results

CTX and P1NP concentrations peaked at six weeks in all groups. Elevated six-week CTX and P1NP were associated with radiological healing at 12 weeks post-injury (odds ratio (OR) 10.5; 95% confidence interval 2.71 to 53.5, p = 0.002). We found no association between CTX or P1NP and functional healing. Baseline serum 25(OH)D showed a weak inverse relationship with P1NP (p = 0.036) and CTX (p = 0.221) at 12 weeks, but we observed no association between vitamin D supplementation and either BTM.

Conclusion

Given the association between six-week BTM concentrations and three-month radiological fracture healing, CTX and P1NP appear to be potential surrogate markers of fracture healing.

Cite this article: Bone Joint Res 2022;11(4):239–250.

Roles of Trauma CT and CTA in Salvaging the Threatened or Mangled Extremity

Extremity arterial injuries account for up to 50% of all arterial traumas. The speed, accuracy, reproducibility, and close proximity of modern CT scanners to the trauma bay have led to the liberal use of CT angiography (CTA) when a limb is in ischemic jeopardy or is a potential source of life-threatening hemorrhage. The radiologist plays a critical role in the rapid communication of findings related to vessel transection and occlusion. Another role of CT that is often overlooked involves adding value to surgical planning. The following are some of the key questions addressed in this review: How does CTA help determine whether a limb is salvageable? How do concurrent multisystem injuries affect decision making? Which arterial injuries can be safely managed with observation alone? What damage control techniques are used to address compartment syndrome and hemorrhage? What options are available for definitive revascularization? Ideally, the radiologist should be familiar with the widely used Gustilo-Anderson open-fracture classification system, which was developed to prognosticate the likelihood of a functional limb salvage on the basis of soft-tissue and bone loss. When functional salvage is feasible or urgent hemorrhage control is required, communication with trauma surgeon colleagues is augmented by an understanding of the unique surgical, endovascular, and hybrid approaches available for each anatomic region of the upper and lower extremities. The radiologist should also be familiar with the common postoperative appearances of staged vascular, orthopedic, and plastic reconstructions for efficient clinically relevant reporting of potential down-range complications. Online supplemental material is available for this article. ^©RSNA, 2022.

Bone Union Assessment with Computed Tomography (CT) and Statistical Associations with Mechanical or Histological Testing: A Systematic Review of Animal Studies

Objective and accurate assessment of bone union after a fracture, arthrodesis, or osteotomy is relevant for scientific and clinical purposes. Bone union is most accurately imaged with computed tomography (CT), but no consensus exists about objective assessment of bone union from CT images. It is unclear which CT-generated parameters are most suitable for bone union assessment. The aim of this review of animal studies is to find which CT-generated parameters are associated most strongly with actual bone union. Scientific databases were systematically searched. Eligible studies were studies that (1) were animal studies, (2) created a fracture, (3) assessed bone union with CT, (4) performed mechanical or histological testing as measure of actual bone union, and (5) associated CT-generated outcomes to mechanical or histological testing results. Two authors selected eligible studies and performed risk of bias assessment with QUADAS-2 tool. From 2567 studies that were screened, thirteen studies were included. Most common CT parameters that were investigated were bone mineral density, bone volume, and total callus volume. Studies showed conflicting results concerning the associations of these parameters with actual bone union. CT-assessed torsional rigidity (assessed by three studies) and callus density (assessed by two studies) showed best results. The studies investigating these two parameters reported moderate to strong associations with actual bone union. CT-assessed torsional rigidity and callus density seem the most promising parameters to represent actual bone union after a fracture, arthrodesis, or osteotomy.Prospero trial registration number: CRD42020164733.

Modal Frequencies Associations with Musculoskeletal Components of Human Legs for Extracorporeal Bone Healing Assessment Based on a Vibration Analysis Approach

Reliable and quantitative assessments of bone quality and fracture healing prompt well-optimised patient healthcare management and earlier surgical intervention prior to complications of nonunion and malunion. This study presents a clinical investigation on modal frequencies associations with musculoskeletal components of human legs by using a prototype device based on a vibration analysis method. The findings indicated that the first out-of-plane and coupled modes in the frequency range from 60 to 110 Hz are associated with the femur length, suggesting these modes are suitable quantitative measures for bone evaluation. Furthermore, higher-order modes are shown to be associated with the muscle and fat mass of the leg. In addition, mathematical models are formulated via a stepwise regression approach to determine the modal frequencies using the measured leg components as variables. The optimal models of the first modes consist of only femur length as the independent variable and explain approximately 43% of the variation of the modal frequencies. The subsequent findings provide insights for further development on utilising vibration-based methods for practical bone and fracture healing monitoring.

FDA-approved bone grafts and bone graft substitute devices in bone regeneration

To induce bone regeneration there is a complex cascade of growth factors. Growth factors such as recombinant BMP-2, BMP-7, and PDGF are FDA-approved therapies in bone regeneration. Although, BMP shows promising results as being an alternative to autograft, it also has its own downfalls. BMP-2 has many adverse effects such as inflammatory complications such as massive soft-tissue swelling that can compromise a patient's airway, ectopic bone formation, and tumor formation. BMP-2 may also be advantageous for patients not willing to give up smoking as it shows bone regeneration success with smokers. BMP-7 is no longer an option for bone regeneration as it has withdrawn off the market. PDGF-BB grafts in studies have shown PDGF had similar fusion rates to autologous grafts and fewer adverse effects. There is also an FDA-approved bioactive molecule for bone regeneration, a peptide P-15. P-15 was found to be effective, safe, and have similar outcomes to autograft at 2 years post-op for cervical radiculopathy due to cervical degenerative disc disease. Growth factors and bioactive molecules show some promising results in bone regeneration, although more research is needed to avoid their adverse effects and learn about the long-term effects of these therapies. There is a need of a bone regeneration method of similar quality of an autograft that is osteoconductive, osteoinductive, and osteogenic. This review covers all FDA-approved bone regeneration therapies such as the "gold standard" autografts, allografts, synthetic bone grafts, and the newer growth factors/bioactive molecules. It also covers international bone grafts not yet approved in the United States and upcoming technologies in bone grafts.

The problem of dating fractures: A retrospective observational study of radiologic features of fracture healing in adults

Accurate dating of bone fractures can be crucial in the context of forensic trauma analysis since it may provide essential information for the corroboration or contradiction of statements by victims or suspects in cases of domestic abuse or torture. The different stages of bone healing have been well described in the existing literature, and some previous studies attempted to define related timelines particularly in the paediatric population. However, the bone healing process can be very variable and despite the importance of the topic in the forensic field, so far little is known about the radiological appearance of bone fractures at different healing stages, and how this correlates with time, especially in an adult population. The aim of this retrospective observational study was to describe the temporal aspect of pre-defined healing stages as they appear on radiographs of tubular bone fractures in adults, and explore the effect of potential cofounding variables. A dynamic nomogram was developed as a user-friendly tool to be eventually applied in clinical or medico-legal settings. This study showed that the posttraumatic time interval (PTTI) increased progressively with the pre-defined healing stages. However, confounding factors, such as patients' age, sex, and location of the fracture need to be accounted for in the final estimation model. Further studies are needed to explore more potentially confounding variables to refine the presented outcomes. Better knowledge of the effect of different confounding variables in the dating of fracture healing will contribute to greater accuracy of PTTI estimation of bone fractures in adults.

A Novel Capacitive Measurement Device for Longitudinal Monitoring of Bone Fracture Healing

The healing process of surgically-stabilised long bone fractures depends on two main factors: (a) the assessment of implant stability, and (b) the knowledge of bone callus stiffness. Currently, X-rays are the main diagnostic tool used for the assessment of bone fractures. However, they are considered unsafe, and the interpretation of the clinical results is highly subjective, depending on the clinician’s experience. Hence, there is the need for objective, non-invasive and repeatable methods to allow a longitudinal assessment of implant stability and bone callus stiffness. In this work, we propose a compact and scalable system, based on capacitive sensor technology, able to measure, quantitatively, the relative pins displacements in bone fractures treated with external fixators. The measurement device proved to be easily integrable with the external fixator pins. Smart arrangements of the sensor units were exploited to discriminate relative movements of the external pins in the 3D space with a resolution of 0.5 mm and 0.5°. The proposed capacitive technology was able to detect all of the expected movements of the external pins in the 3D space, providing information on implant stability and bone callus stiffness.

Bone Healing and Inflammation: Principles of Fracture and Repair

Bones comprise a significant percentage of human weight and have important physiologic and structural roles. Bone remodeling occurs when healthy bone is renewed to maintain bone strength and maintain calcium and phosphate homeostasis. It proceeds through four phases: (1) cell activation, (2) resorption, (3) reversal, and (4) bone formation. Bone healing, on the other hand, involves rebuilding bone following a fracture. There are two main types of bone healing, primary and secondary. Inflammation plays an integral role in both bone remodeling and healing. Therefore, a tightly regulated inflammatory response helps achieve these two processes, and levels of inflammation can have detrimental effects on bone healing. Other factors that significantly affect bone healing are inadequate blood supply, biomechanical instability, immunosuppression, and smoking. By understanding the different mechanisms of bone healing and the factors that affect them, we may have a better understanding of the underlying principles of bony fixation and thereby improve patient care.

The orthopaedic surgeon's clinical and experimental experience affect methods used for the fracture healing assessment (FHA) - An International Survey

Detection of fracture healing (FH), which depends on assessment methods, is a crucial factor affecting treatment. The study aimed to examine orthopedic surgeons in terms of practical methods of fracture healing (FHA) assessment (physical, imaging, measurement, and laboratory) and to check whether surgeons participating in clinical and laboratory experiments or only clinical practitioners prefer different FHA methods. An International Survey on Fracture Healing Assessment Methods was developed and distributed through the Web-based survey portal. Ninety-three orthopedic surgeons, on average age 41.46 years, from 24 countries participated in the study. Thirty-one respondents (33.3%) reported dealing with fractures both in the clinic and in experimental studies, six (6.5%) reported dealing with fractures only in laboratory research work, and fifty-six (60.2%) indicated that they dealt with fractures only clinically. The survey's internal consistency was significantly high (Cronbach's alpha coefficients ranged from 0.84 to 0.96). The majority of respondents (80.83%) use specific clinical criteria to define a fracture union. The FHA was mainly based on the physical examination and plain radiograms. Laboratory findings, patient-oriented outcomes scores, and quantitative methods are rarely used. Orthopaedic surgeons dealing with fractures both in the clinic and in laboratory fracture research studies are more likely to use more quantitative FHA methods. Future research is needed to improve the international standard of the FHA methods for use in research, clinical trials, and clinical practice. Using a quantitative, reliable, and standardized approach, including online support, can be valuable for increasing compliance in the orthopedic surgeon population, effectively improving the adherence of fracture healing assessment in clinical conditions, and improving early detection of fracture healing disorders, improving fracture efficiency treatment.

The emergency medicine management of clavicle fractures

BACKGROUND

Clavicle fractures are common. An emergency physician needs to understand the diagnostic classifications of clavicle fractures, have a plan for immobilization, identify associated injuries, understand the difference between treating pediatric and adult patients, and have an approach to multimodal pain control. It is also important to understand when expert orthopedic consultation or referral is indicated.

OBJECTIVE OF THE REVIEW

To provide an evidence-based review of clavicle fracture management in the emergency department.

DISCUSSION

Clavicle fractures account for up to 4% of all fractures evaluated in the emergency department. They can be separated into midshaft, distal, and proximal fractures. They are also classified in terms of their degree of displacement, comminution and shortening. Emergent referral is indicated for open fractures, posteriorly displaced proximal fractures, and those with emergent associated injuries. Urgent referral is warranted for fractures with greater than 100% displacement, fractures with >2 cm of shortening, comminuted fractures, unstable distal fractures, and floating shoulder. Nondisplaced or minimally displaced fractures with no instability or associated neurovascular injury are managed non-operatively with a sling. Pediatric fractures are generally managed conservatively, with adolescents older than 9 years-old for girls and 12 years-old for boys being treated using algorithms that are similar to adults.

CONCLUSIONS

When encountering a patient with a clavicle fracture in the emergency department the fracture pattern will help determine whether emergent consultation or urgent referral is indicated. Most patients can be discharged safely with sling immobilization and appropriate outpatient follow-up.

Pain during physical examination of a healing upper extremity fracture

The evidence that symptom intensity and magnitude of limitations correlate with thoughts and emotions means that subjective signs, such as pain with physical examination, reflect both physical and mental health. During a 1-month evaluation of a rapidly healing upper extremity fracture with no risk of nonunion, 117 people completed measures of adaptiveness to pain and pain during the physical examination. Greater pain during examination correlated with less adaptive responses to pain and older age. This finding raises questions about using tenderness to assess fracture union.Level of evidence: II.

Failure analysis and recommendations for treatment of posttraumatic non-unions of the distal humerus during childhood

PURPOSE

Non-unions of the distal humerus are rare complications of common children's fractures such as radial condyle fractures and supracondylar fractures. The aim of this paper was to update the knowledge about etiology, reasons, management, and results of these troublesome, and sometimes debilitating entities.

METHODS

The sparse literature concerning nonunions following condylar or supracondylar fractures was analyzed together with the presentation of some typical clinical cases.

RESULTS

In most of the cases, non-unions were induced by neglect, unstable fixation, too early implant removal, too much revision surgery, and an inconsequent transfer of follow-up algorithms, or combinations of the above. Treatment of non-union should start as early as possible because the effort of required surgery increases with time that the nonunion has been neglected. Often a combination of stable fixation of the pseudarthrosis and correction of the elbow axis are necessary to achieve a satisfying outcome.

CONCLUSION

In pediatric traumatology, qualified and consequent care for children's fractures of the distal humerus can prevent rare complications such as non-unions in almost any situation. If such a disturbance of healing is noticed, immediate and adequate, i.e. children specific surgical consequences achieve best results.

Changes of bone turnover markers after elderly hip fracture surgery

INTRODUCTION

Bone turnover markers (BTMs) can be used to monitor bone metabolism, while the actual clinical changing in hip fracture had not been certified to evaluate the changes of BTMs during the healing process after surgery of elderly hip fractures; and to get the effects of operation type, gender, serum 25(OH)D level, and age on bone turnover markers.

MATERIALS AND METHODS

A total of 100 elderly cases with hip fracture were selected, including 74 females and 26 males, and the patients were followed to 180-230 days after surgery. Serum levels of N-propeptide of type 1 collagen (P1NP), C-terminal crosslinking telopeptides of type 1 collagen (CTX), Osteocalcin (OC), and 25 hydroxy vitamin D (25OHD) were investigated. Bone mineral density (BMD) was measured with dual-energy X-ray absorptiometry (DXA).

RESULTS

(1) P1NP and CTX showed peak time at 30-60 days after operation, while OC keep going even at 180-230 days; P1NP showed less than 4 times elevation during healing, CTX and OC only had less than 2 times rise. (2) Female had higher serum CTX and OC than male, intramedullary nailing for intertrochanteric fracture patients had higher P1NP than hip replacement for femoral neck fracture patients, and both the degrees of increase were less than 50%. (3) Serum average 25(OH)D level had no effect on BTMs during the fracture healing; different from the young old (65-84 years), serum OC level of eldest older patients(≥ 85 years) decreased early in the process of fracture healing.

CONCLUSIONS

BTMs reached the peak level in 30-60 days after surgery, P1NP showed less than 4 times elevation, and CTX and OC had less than 2 times rise. It was not necessary to take gender into account when observing P1NP, and it was not necessary to take fracture and operation type into account when observing CTX and OC.

Quick-DASH as a main early outcome of humeral shaft fractures: A Latin American multicenter prospective study

PURPOSE

The main objective of this study was to evaluate the Quick-Disabilities of the Arm, Shoulder and Hand Score (DASH) score as the main early (90 days) outcome in a prospective multicenter observational Latin American study on isolated humeral shaft fractures.

METHODS

From December 2015 to April 2017, in six Latin American countries, patients 18 years or older with a closed, isolated nonpathological 12A, 12B, or 12C AO/OTA (Arbeitsgemeinschaft für Osteosynthesefragen/Orthopaedic Trauma Association) fractures were included. The 90 (±10)-day Quick-DASH score was used to compare the results of the different treatments. The secondary outcomes were patient treatment satisfaction, shoulder and elbow range of motion, and radiographic evaluation.

RESULTS

A total of 92 patients successfully completed the Quick-DASH questionnaire. Surgical treatments resulted in better outcomes than nonsurgical treatment, but only minimally invasive plate osteosynthesis produced significantly lower Quick-DASH scores than nonsurgical treatment (p < 0.05). There were strong correlations between patient self-evaluation and the Quick-DASH score (p < 0.0005) but not between the Quick-DASH score and radiographic fracture healing. No significant difference was found between the treatments regarding the rate of return to work, but the medical center had a significant influence on treatment choice (p < 0.0005).

CONCLUSION

The high correlation between Quick-DASH score and patient satisfaction and functional outcome indicates that the Quick-DASH questionnaire is a suitable tool for evaluating adult humeral shaft fracture outcomes. Patients with a Quick-DASH score below 15 could be considered recovered, and patients with a Quick-DASH score above 40 could be considered not yet recovered. Quick-DASH scores were not significantly associated with radiographic fracture healing.

Modeling Complex Orthopedic Trauma in Rodents: Bone, Muscle and Nerve Injury and Healing

Orthopedic injury can occur from a variety of causes including motor vehicle collision, battlefield injuries or even falls from standing. Persistent limb pain is common after orthopedic injury or surgery and presents a unique challenge, as the initiating event may result in polytrauma to bone, muscle, and peripheral nerves. It is imperative that we understand the tissue-specific and multicellular response to this unique type of injury in order to best develop targeted treatments that improve healing and regeneration. In this Mini Review we will first discuss current rodent models of orthopedic trauma/complex orthotrauma. In the second section, we will focus on bone-specific outcomes including imaging modalities, biomechanical testing and immunostaining for markers of bone healing/turnover. In the third section, we will discuss muscle-related pathology including outcome measures of fibrosis, muscle regeneration and tensile strength measurements. In the fourth section, we will discuss nervous system-related pathology including outcome measures of pain-like responses, both reflexive and non-reflexive. In all sections we will consider parallels between preclinical outcome measures and the functional and mechanistic findings of the human condition.

A novel quantitative and reference-free ultrasound analysis to discriminate different concentrations of bone mineral content

Bone fracture is a continuous process, during which bone mineral matrix evolves leading to an increase in hydroxyapatite and calcium carbonate content. Currently, no gold standard methods are available for a quantitative assessment of bone fracture healing. Moreover, the available tools do not provide information on bone composition. Whereby, there is a need for objective and non-invasive methods to monitor the evolution of bone mineral content. In general, ultrasound can guarantee a quantitative characterization of tissues. However, previous studies required measurements on reference samples. In this paper we propose a novel and reference-free parameter, based on the entropy of the phase signal calculated from the backscattered data in combination with amplitude information, to also consider absorption and scattering phenomena. The proposed metric was effective in discriminating different hydroxyapatite (from 10 to 50% w/v) and calcium carbonate (from 2 to 6% w/v) concentrations in bone-mimicking phantoms without the need for reference measurements, paving the way to their translational use for the diagnosis of tissue healing. To the best of our knowledge this is the first time that the phase entropy of the backscattered ultrasound signals is exploited for monitoring changes in the mineral content of bone-like materials.