IL-17RA Signaling in Prx1+ Mesenchymal Cells Influences Fracture Healing in Mice

Fracture healing is a complex series of events that requires a local inflammatory reaction to initiate the reparative process. This inflammatory reaction is important for stimulating the migration and proliferation of mesenchymal progenitor cells from the periosteum and surrounding tissues to form the cartilaginous and bony calluses. The proinflammatory cytokine interleukin (IL)-17 family has gained attention for its potential regenerative effects; however, the requirement of IL-17 signaling within mesenchymal progenitor cells for normal secondary fracture healing remains unknown. The conditional knockout of IL-17 receptor a (Il17ra) in mesenchymal progenitor cells was achieved by crossing Il17raF/F mice with Prx1-cre mice to generate Prx1-cre; Il17raF/F mice. At 3 months of age, mice underwent experimental unilateral mid-diaphyseal femoral fractures and healing was assessed by micro-computed tomography (µCT) and histomorphometric analyses. The effects of IL-17RA signaling on the osteogenic differentiation of fracture-activated periosteal cells was investigated in vitro. Examination of the intact skeleton revealed that the conditional knockout of Il17ra decreased the femoral cortical porosity but did not affect any femoral trabecular microarchitectural indices. After unilateral femoral fractures, Il17ra conditional knockout impacted the cartilage and bone composition of the fracture callus that was most evident early in the healing process (day 7 and 14 post-fracture). Furthermore, the in vitro treatment of fracture-activated periosteal cells with IL-17A inhibited osteogenesis. This study suggests that IL-17RA signaling within Prx1+ mesenchymal progenitor cells can influence the early stages of endochondral ossification during fracture healing.

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

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

Close negative correlation of local and circulating Dickkopf-1 and Sclerostin levels during human fracture healing

Wnt signaling is critically involved in fracture healing. Existing data predominantly relies on rodent models. Here, we explored local and circulating Dickkopf-1 (DKK1) levels in patients with respect to fracture healing and explore its association to sclerostin (SOST). 69 patients after surgical stabilization of long bone fractures of which six patients had impaired fracture healing were included in this study. Life-style and patient related factors with a known effect on DKK1 and SOST were recorded. DKK1 and SOST concentrations were measured using enzyme-linked immunosorbent assay (ELISA) at the fracture site and in circulation. DKK1 and SOST showed a close inverse correlation. In fracture hematoma and immediately after trauma DKK1 levels were significantly reduced while SOST levels were significantly increased, compared to healthy control. Postoperatively, DKK1 peaked at week 2 and SOST at week 8, again demonstrating a close negative correlation. Age and smoking status affected the balance of DKK1 and SOST, while type 2 diabetes and sex did not demonstrate a significant influence. Early postoperative elevation of SOST without compensatory DKK1 decrease was associated with fracture non-union in younger patients (< 50a). The close inverse correlation and very rapid dynamics of DKK1 and SOST locally as well as systemically suggest their critical involvement during human fracture healing. Importantly, as immediate compensatory feedback mechanism are apparent, we provide evidence that dual-blockade of DKK1 and SOST could be critical to allow for therapeutic efficiency of Wnt targeted therapies for fracture healing.

Approach to Tibial Shaft Nonunions: Diagnosis and Management

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

Flexible nailing: Pushing the indications for diametaphyseal lower-extremity fractures

Elastic stable intramedullary nailing (ESIN) has been shown to be an effective form of surgical management for lower-extremity diametaphyseal fractures in pediatric patients, but studies are limited because ESIN treatment for these fractures is relatively uncommon. We sought to determine whether ESIN can be used effectively in the most distal or proximal short-segment forms of these fractures. We queried the electronic medical record system at Johns Hopkins Hospital using Current Procedural Terminology codes for femur and tibia fractures treated with ESIN in patients under 18 years old between January 2015 and October 2022. Preoperative and postoperative radiographs were subsequently reviewed to identify patients with a proximal or distal third femoral or tibial shaft fracture treated with ESIN and to define criteria for short-segment diametaphyseal fractures. We used Beaty radiological criteria to evaluate radiographic outcomes and Flynn titanium elastic nails (TENs) outcome scale to assess clinical recovery after radiographic evidence of union. There were 43 children who met the inclusion criteria. Among them, 10 patients had short-segment diametaphyseal fractures. There were 22 (51.2%) who sustained femur fractures and 21 (48.8%) who sustained tibia fractures. Using Beaty radiologic criteria, ESIN was associated with more satisfactory outcomes in patients with distal or proximal third shaft fractures (32/33) than in patients with short-segment diametaphyseal fractures (7/10) (P = .03). Using the TENs outcome scale, 21 (63.4%) patients with distal or proximal third shaft fractures had excellent results, 11 (33.3%) had satisfactory results, and 1 (3%) had a poor result. Among patients with short-segment diametaphyseal fractures, 4 (40%) had excellent results, 5 (50%) had satisfactory results, and 1 (10%) had a poor result. There were no differences in TENs outcomes between the groups (P = .24). Patients with short-segment lower-extremity diametaphyseal fractures treated with ESIN had worse radiographic outcomes but did no worse clinically than patients with distal or proximal third shaft fractures. Consequently, ESIN should be considered a safe and effective surgical management option for pediatric patients with even the most distal or proximal forms of these fractures.

[A prospective study on treatment of Sanders type and calcaneal fractures with interlocking intramedullary nail fixation system]

Objective

To explore the effectiveness of interlocking intramedullary nail fixation system for Sanders type Ⅱ and Ⅲ calcaneal fractures by comparing with open surgery.

Methods

Forty patients (40 feet) with Sanders type Ⅱ and Ⅲ calcaneal fractures, who were admitted between May 2020 and December 2022 and met the selection criteria, were included in the study. They were randomly allocated into control group and minimally invasive group using a random number table method, with 20 cases in each group. The patients were treated with the interlocking intramedullary nail fixation system in the minimally invasive group and with steel plate internal fixation via a lateral L-shaped incision in the control group. There was no significant difference between the two groups ( P>0.05) in terms of gender, age, fracture classification and side, cause of injury, time from injury to admission, and preoperative width, length, height, Böhler angle, and Gissane angle of the calcaneus. The operation time, intraoperative blood loss, incision length, hospital stay, fracture healing time, incidence of complications, as well as pre- and post-operative imaging indicators (Böhler angle, Gissane angle, width, height, and length of the calcaneus) and American Orthopaedic Foot and Ankle Society (AOFAS) score of foot were recorded and compared between the two groups.

Results

The incision length, operation time, and hospital stay of the minimally invasive group were significantly shorter than those of the control group, and the intraoperative blood loss significantly reduced ( P<0.05). All patients of the two groups were followed up, with the follow-up time of 8-12 months (mean, 10.2 months) in the minimally invasive group and 8-12 months (mean, 10.4 months) in the control group. No complication occurred in the minimally invasive group after operation. One case of incision epidermal necrosis and 1 case of traumatic arthritis occurred in the control group after operation. However, there was no significant difference in the incidence of complications between the two groups ( P>0.05). At last follow-up, the AOFAS score was significantly higher in the minimally invasive group than in the control group ( P<0.05). Imaging examination showed that the calcaneal fractures of the two groups healed, and there was no significant difference in healing time between the two groups ( P>0.05). Compared with preoperative conditions, the Böhler angle and Gissane angle of the calcaneus in the two groups significantly increased, the width narrowed, and the height and length increased at 3 days after operation and the last follow-up, with significant differences ( P<0.05). There was no significant difference between 3 days after operation and last follow-up ( P>0.05). There was no significant difference between the two groups at each time point ( P>0.05).

Conclusion

The interlocking intramedullary nail fixation system in treatment of Sanders type Ⅱ and Ⅲ calcaneal fractures has the advantages of minimal trauma, shortened hospital stay, reliable fracture reduction and fixation, and satisfactory foot function recovery.

Overexpression of miR-7-5p Promoted Fracture Healing Through Inhibiting LRP4 and Activating Wnt/β-Catenin Pathway

Background. The bone healing after fracture had a great impact on the patients' life quality. However, how miR-7-5p participated in fracture healing has not been investigated. Methods. For in vitro studies, the pre-osteoblast cell line MC3T3-E1 was obtained. The male C57BL/6 mice were purchased for in vivo experiments, and the fracture model was constructed. Cell proliferation was determined by CCK8 assay, and alkaline phosphatase (ALP) activity was measured by commercial kit. Histological status was evaluated using H&E and TRAP staining. The RNA and protein levels were detected via RT-qPCR and western blotting, respectively. Results. Overexpression of miR-7-5p increased cell viability and ALP activity in vitro. Moreover, in vivo studies consistently indicated that transfection of miR-7-5p improved the histological status and increased the proportion of TRAP-positive cells. Overexpression of miR-7-5p suppressed LRP4 expression while upregulated Wnt/β-catenin pathway. Conclusion. MiR-7-5p decreased LRP4 level and further activated the Wnt/β-catenin signaling, facilitating the process of fracture healing.

Treatment of presumed aseptic non-union of the humeral shaft by osteosynthesis combining intramedullary nailing and screw plate

In 2020, the most common treatment for presumed aseptic non-union of the humeral shaft seems to be decortication, often associated with bone autografting, and stabilized by a screw plate. We propose to evaluate an original technique of rigid osteosynthesis combining intramedullary nailing and screw plate. Between January 2004 and January 2020, 45 patients underwent treatment of presumed aseptic non-union of the humeral shaft by osteosynthesis combining intramedullary nailing and a screw plate. The minimum radio-clinical follow-up was one year postoperatively. The series included 19 men and 26 women with a mean age of 53 years (range 19-84 years). Bone consolidation was achieved in 43 patients, a rate of 95.5%. Comparing patients who achieved bone consolidation with the two failed consolidations did not reveal any statistically significant factor. Interobserver agreement was almost perfect (k=0.93) for the use of the RUST for humeral shaft fractures treated with intramedullary nailing and screw plate. In our study, the treatment of presumed aseptic non- union of the humeral shaft with an osteosynthesis combining intramedullary nailing and screw plate gives, with 95.5% of bone consolidation, results equal to or even superior to the different treatments currently described in the literature.

Primary Ankle Fusion Using an Antegrade Nail Into the Talus for Early Treatment of OTA Type C3 Distal Tibial Plafond Fractures: A Preliminary Report

BACKGROUND

Type C3 distal tibial plafond fractures consistently show poor outcomes with high complication rates and significant risk of posttraumatic arthritis. We describe a minimally invasive technique of performing a primary ankle fusion using an anterograde tibial nail and compare our early results to traditional methods of fixation.

METHODS

During the acute admission, the patient undergoes an arthroscopic preparation of the ankle joint and insertion of an anterograde nail into the talus. This technique is described in detail and presented alongside a retrospective 5-year review of all adult C3 distal tibial plafond fractures from our center.

RESULTS

Twenty-six patients (8 open fractures) had been fixed traditionally using open reduction internal fixation (24 patients) and circular frames (2 patients) with an average follow-up of 20 months. Those internally fixed had protected weightbearing for 3 months. Complications included deep infection (12%), nonunion (8%), malunion (4%), severe posttraumatic osteoarthritis (27%), and the secondary conversion to ankle replacement/fusion (12%) requiring an average of 3 reoperations.Six patients underwent primary fusion (3 open fractures) with an average follow-up of 18 months. Patients were allowed to immediately weightbear. There were no reported complications and the primary fusion group demonstrated shorter hospital stays, faster return to work, and higher mean self-reported foot and ankle score (SEFAS) compared to those treated with ORIF.

CONCLUSION

C3 distal tibial plafond fractures are difficult to manage and there has not been a satisfactory method of treating them that allows early return to work, has a low risk of complications, and reduces the risk of posttraumatic tibiotalar arthritis.We present our initial results with a method that uses traditional arthroscopic techniques to prepare the tibiotalar joint together with minimally invasive anterograde tibiotalar nailing. In this initial report of a small group of patients, we found that surgery can be performed once the swelling has subsided after injury and that allowing weightbearing as tolerated did not appear to have a negative effect on initial outcomes.

LEVEL OF EVIDENCE

Level III, retrospective comparative study.

Technical aspects that may affect the outcomes of pediatric patients with both-bone forearm diaphyseal fractures treated using elastic stable intramedullary nails

We assessed the radiological and functional results of pediatric both-bone forearm diaphyseal fractures treated using elastic stable intramedullary nails (ESINs), as well as factors affecting the results. In total, 36 patients (33 males and three females; mean age, 11.6 years) were included. The mean follow-up time was 41.5 (18-96) months. Patient demographic characteristics and the details of the surgical techniques were analyzed retrospectively. In addition to standard radiographic evaluations, the ratio between the nail diameter and medullary canal diameter (ND/MCD) was measured, as well as the maximal radial bowing. According to the criteria of Price and Flynn, 28 (77.8%) and eight (22.2%) patients had excellent and good results, respectively. There were no cases of nonunion or delayed union. There was no significant difference in functional or radiological results according to whether titanium nails (24 patients) or stainless steel nails (12 patients) were used (all P  > 0.05). Nail prebending (performed in 19 patients) did not affect the functional or radiological results ( P  > 0.05). Loss of reduction was observed in four patients with an ND/MCD ratio <40%. The maximal radial bowing improved in all patients. The mean change was significantly greater in patients with diastases and 22D/4.1 fractures. Regardless of nail type or prebending status, surgery using ESIN placement effectively treats both-bone forearm diaphyseal fractures; radial bow remodeling outcomes are excellent. We recommend that the ND/MCD ratio should be 40-70%.

Comparing outcomes of plate augmentation, nail exchange, and nail exchange with plate augmentation in the treatment of atrophic femoral shaft nonunion after intramedullary nailing: a multicenter retrospective study

INTRODUCTION

Intramedullary (IM) nailing is the treatment of choice for femoral shaft fractures, but nonunion rates have been reported to be as high as 12%. Surgical interventions for nonunion involve exchange nailing or plate augmentation. Recently, a combined treatment of exchange nailing and plate augmentation has demonstrated good results, but its comparative effectiveness remains unclear. This study aimed to compare the clinical and radiographic outcomes of three different surgical interventions for atrophic femoral shaft nonunion, and investigate the factors that affect bone healing after reoperation.

MATERIALS AND METHODS

A retrospective study was conducted at five university hospitals involving 149 patients with aseptic atrophic nonunion after IM nailing. These patients underwent reoperation with plate augmentation, exchange nailing, or combined treatment. Clinical and radiographic outcomes were assessed and compared according to reoperation procedure. Logistic regression analysis was performed to identify factors affecting persistent nonunion after reoperation.

RESULTS

Of the cohort, 57 patients underwent plate augmentation, 64 underwent exchange nailing, and 28 received combined treatment. There were no significant differences in patient demographics among the groups. Exchange nailing produced a significantly lower union rate than did the combined treatment (82.8% vs. 100%, p = 0.016), whereas no significant difference was observed in the union rate and time to the union between plate augmentation and the combined treatment. Combined treatment showed the longest operative time and the greatest transfusion requirements. The risk factors for persistent nonunion included age, absence of autogenous bone grafts, and use of an exchange nailing technique.

CONCLUSIONS

Exchange nailing as a treatment for atrophic femoral shaft nonunion after IM nailing resulted in a lower union rate. The efficacy of the combined treatment requires further study, and persistent nonunion may be influenced by age, bone grafting, and surgical techniques. A comprehensive approach targeting both biological environment and mechanical stability is crucial in the treatment of atrophic femoral shaft nonunion.

Surgical Reconstruction of Canine Nonunion Fractures Using Bone Morphogenetic Protein-2-loaded Alginate Microbeads and Bone Allografts

BACKGROUND/AIM

Effective treatment of nonunion fractures is challenging as it requires a biological and mechanical environment to promote sufficient osteogenesis. Herein, we present a case series in which we evaluated the clinical efficacy of bone morphogenetic protein-2 (BMP-2)-loaded alginate microbeads and allografts in two dogs with nonunion fractures.

CASE REPORT

A 3-year-old, 2.3-kg, spayed female Pomeranian (Case 1) presented with intermittent lameness of the left forelimb after radial and ulnar fracture repair 8 weeks prior. A 4-year-old, 4.8-kg, spayed female Pomeranian (Case 2) was referred for non-weight-bearing lameness of the left hindlimb due to implant failure following left tibial fracture repair. Both dogs had atrophic bone ends and no bridging calluses at the fracture site on radiographs, and were diagnosed with nonviable nonunion fractures of the radius/ulna and tibia, respectively. The surgical approach involved implant removal, debridement, and fracture gap reconstruction. BMP-2 was loaded into alginate microbeads for a prolonged release with bone allograft chips in both cases. In Case 1, bead grafts were applied directly at the fracture site, while in Case 2, they were implanted inside a frozen cortical bone allograft as a scaffold to fill the large gap. Postoperative radiography revealed excessive callus formation, early radiographic bone union, and cortical bone remodeling, in line with improved lameness scores. At the final follow-up, gait was improved and the desired bone length and shape were achieved in both cases.

CONCLUSION

Simultaneous use of osteoinductive BMP-2 alginate microbeads and osteoconductive bone allografts yielded functionally and structurally favorable outcomes in canine nonunion fractures, without major complications.

Wound infection and healing in minimally invasive plate osteosynthesis compared with intramedullary nail for distal tibial fractures: A meta-analysis

To systematically explore the effects of minimally invasive plate osteosynthesis (MIPO) versus intramedullary nail (IMN) on wound infection and wound healing in patients with distal tibia fractures. A computerised search of PubMed, Web of Science, Cochrane Library, Embase, Wanfang, China Biomedical Literature Database (CBM) and China National Knowledge Infrastructure databases was performed, from their inception to October 2023, to identify relevant studies on the application of MIPO and IMN in patients with distal tibial fractures. The quality of the included literature was evaluated by two researchers based on inclusion and exclusion criteria, and basic information of the literature was collected, with wound infection, postoperative complications and wound healing time as the main indicators for analysis. Stata 17.0 software was applied for analysis. Overall, 23 papers and 2099 patients were included, including 1026 patients in the MIPO group and 1073 patients in the IMN group. The results revealed, when compared with IMN treatment, patients with distal tibia fractures who underwent MIPO treatment had a lower incidence of postoperative complications (OR = 0.33, 95% CI: 0.25-0.42, p < 0.001) and a shorter wound healing time (SMD = -1.00, 95% CI: -1.51 to -0.49, p < 0.001), but the incidence of postoperative wound infection was higher (OR = 2.01, 95% CI: 1.35-3.01, p = 0.001). Both MIPO and IMN are excellent treatments for distal tibia fractures. MIPO is effective in reducing the incidence of complications as well as shortening the time of wound healing time but increases the risk of wound infection. In clinical practice, surgeons can make individual choices based on the patient's wishes and proficiency in both techniques.

Macrophage-mediated fracture healing: Unraveling molecular mechanisms and therapeutic implications using hydrogel-based interventions

Fracture healing is a complex biological process that involves the orchestrated interplay of various cells and molecular signaling pathways. Among the key players, macrophages have emerged as critical regulators of fracture repair, influencing inflammation, tissue remodeling, and angiogenesis. Recent advances in hydrogel-based therapeutics have provided exciting opportunities to leverage the modulatory effects of macrophages for improving fracture healing outcomes. In the present study, we review the importance of macrophages in fracture repair and their potential therapeutic role in hydrogel-based interventions. We discuss the molecular mechanisms underlying macrophage-mediated effects on fracture healing, and how hydrogels can be utilized as a platform for macrophage modulation. Furthermore, we highlight the translation of hydrogel-based therapies from bench to bedside, including preclinical and clinical studies, and the challenges and opportunities in harnessing the therapeutic potential of macrophages in fracture repair. Overall, understanding the importance of macrophages in fracture healing and the potential of hydrogel-based therapeutics to modulate macrophage responses can pave the way for developing innovative approaches to improve fracture healing outcomes.

Outcomes of Humerus Nonunion Surgery in Patients With Initial Operative Fracture Fixation

OBJECTIVES

To describe outcomes following humerus aseptic nonunion surgery in patients whose initial fracture was treated operatively and to identify risk factors for nonunion surgery failure in the same population.

METHODS

DESIGN

Retrospective case series.

SETTING

Eight, academic, level 1 trauma centers.

PATIENTS SELECTION CRITERIA

Patients with aseptic humerus nonunion (OTA/AO 11 and 12) after the initial operative management between 1998 and 2019.

OUTCOME MEASURES AND COMPARISONS

Success rate of nonunion surgery.

RESULTS

Ninety patients were included (56% female; median age 50 years; mean follow-up 21.2 months). Of 90 aseptic humerus nonunions, 71 (78.9%) united following nonunion surgery. Thirty patients (33.3%) experienced 1 or more postoperative complications, including infection, failure of fixation, and readmission. Multivariate analysis found that not performing revision internal fixation during nonunion surgery (n = 8; P = 0.002) and postoperative de novo infection (n = 9; P = 0.005) were associated with an increased risk of recalcitrant nonunion. Patient smoking status and the use of bone graft were not associated with differences in the nonunion repair success rate.

CONCLUSIONS

This series of previously operated aseptic humerus nonunions found that more than 1 in 5 patients failed nonunion repair. De novo postoperative infection and failure to perform revision internal fixation during nonunion surgery were associated with recalcitrant nonunion. Smoking and use of bone graft did not influence the success rate of nonunion surgery. These findings can be used to give patients a realistic expectation of results and complications following humerus nonunion surgery.

LEVEL OF EVIDENCE

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

Comparative Clinical Effects and Risk Factors Associated With Vitamin D in Foot and Ankle Fracture and Arthrodesis Healing

Vitamin D deficiency in relation to bone metabolism and healing has been controversial and not well studied. However, hypovitaminosis has been widely identified within the orthopedic patient population. The current best evidence suggests a lack of data on this important topic. The ability to assess patients for optimum bone healing and metabolism is still in question due to lack of a suitable reliable biomarker and multiple other unknown variables affecting bone metabolism. To compound this effect, popular dermatological precautions in the last 20 to 30 years of avoiding sunlight also have the effect of further reducing serum vitamin D production in the skin. As a proof of concept, we performed a preliminary comparative observational retrospective review of orthopedic patients undergoing fracture and arthrodesis osseous healing to determine how serum vitamin D levels are associated with bone healing along with their confounding comorbidities. Based on our review, the current accepted vitamin D levels (≥20 ng/mL) are low and insufficient for fractures and for arthrodesis osseous healing due to observed high rates (>35%) of delayed unions, and an increased (>90%) in the number of multiple confounding comorbidities affecting bone healing process that are often not mentioned or captured in this type of study in previous literature. Obesity and diabetes are significant contributory risks factors, and the preliminary findings suggest that the current accepted adequate levels may not be enough for osseous healing. These low vitamin D levels appear to affect bone healing and prolong treatment, with worsening trends with diabetes and obesity comorbidities.

Effect of different composite plates on the healing of femoral fractures

In this paper, the effects of different composite plates on the healing of femoral fractures were studied by numerical simulation. The healing model of femoral fracture was established by ABAQUS display solver. Based on the fuzzy logic theory, the process of callus differentiation at femoral fracture was considered under the joint action of biological variables and mechanical stimulation, and the healing process of femur was simulated. Compare the stress on the screw, concentration of callus bone and cartilage, and callus healing performance of the carbon/epoxy composite (WSN3k) plate, glass/polypropylene composite (Twintex) plate, and stainless steel plate at various stages of bone healing, and investigate the impact of composite plates on the bone healing process. The results showed that the modulus of the plate had a notable impact on bone healing. Compared to stainless steel plate, the composite plate (due to its lower stiffness) exhibiting superior healing performance. Altering the sequence of composite laminates may modify the bone healing efficiency, and the wsn3k [0]18 composite plate exhibits superior healing performance.

Effect of postoperative fracture gap on bone union: A retrospective cohort analysis of simple femoral shaft fractures

BACKGROUND

Intramedullary nailing (IMN) is considered the gold-standard treatment for femoral shaft fractures. The post operative fracture gap is commonly recognized as a risk factor for nonunion. However, no evaluation standard for measuring the fracture gap size has yet been established. In addition, the clinical implications of the fracture gap size have also not been determined so far. This study aims to clarify how we should evaluate fracture gaps when assessing simple femoral shaft fractures with radiographs and to determine the acceptable cut-off value of the fracture gap size in simple femoral shaft fractures.

METHOD

A retrospective observational study with a consecutive cohort was conducted at the trauma center of a university hospital. We investigated the fracture gap using postoperative radiography and the postoperative bone union of transverse and short oblique femoral shaft fractures fixed by IMN. The receiver operating characteristic curve analysis was conducted to obtain the fracture gap's mean, minimum, and maximum cut-off values. Fisher's exact test was used at the cut-off value of the most accurate parameter.

RESULTS

In the four nonunions among the 30 cases, the analysis using ROC curves revealed that the maximum value had the highest accuracy among the maximum, minimum, and mean values of fracture-gap size. The cut-off value was determined to be 4.14 mm with high accuracy. Fisher's exact test showed that the incidence of nonunion was higher in the group with a maximum fracture gap of 4.14 mm or greater (risk ratio = not applicable, risk difference = 0.57, P = 0.001).

CONCLUSION

In simple transverse and short oblique femoral shaft fractures fixed with IMN, the fracture gap on radiographs should be evaluated by the maximum gap in the AP and lateral views. The remaining maximum fracture gap of ≥4.14 mm would be a risk factor for nonunion.

5-Year Radiographic and Functional Outcomes of Nonoperative Treatment of Completely Displaced Midshaft Clavicular Fractures in Teenagers

BACKGROUND

Optimal treatment of completely displaced midshaft clavicular fractures in adolescents remains controversial, with some favoring surgical management and others favoring a nonoperative approach. Few studies have comprehensively assessed longer-term nonoperative outcomes.

PURPOSE

To prospectively assess patient-reported outcomes (PROs) and radiographic remodeling ≥5 years after injury in teenagers undergoing nonoperative treatment of completely displaced clavicular fractures.

STUDY DESIGN

Case series; Level of evidence, 4.

METHODS

Adolescent patients previously enrolled in a prospective study from a single institution with nonoperatively treated, completely displaced midshaft clavicular fractures ≥5 years from injury were eligible for the study. Patients were clinically evaluated for scapular dyskinesia and strength deficits. Bilateral clavicular imaging assessed residual shortening, displacement, and angulation. PROs included the American Shoulder and Elbow Surgeons (ASES), the shortened version of the Disabilities of the Arm, Shoulder and Hand (QuickDASH), Marx Shoulder Activity Scale, cosmesis, and return to sports data.

RESULTS

A total of 24 patients were available for the follow-up, of whom 17 (71%) consented to additional imaging. The mean cohort age at the time of injury was 14.5 ± 1.1 years, with 88% being male. At a mean follow-up of 6.1 years, all fractures had healed, with no patient requiring secondary interventions. Significant remodeling was observed across all measurements, with improvements of 70% in shortening (22.8 to 6.8 mm; P < .001), 73% in superior displacement (13.4 to 3.6 mm; P < .001), and 83% in angulation (10.4° to 1.8°; P < .001). Thirteen patients (72%) had a >2-cm initial shortening, and all remodeled to <2 cm. PROs were almost universally excellent, with mean ASES, QuickDASH, and Marx activity scores of 99 ± 3, 1 ± 3, and 20 ± 1, respectively, with 79% of patients reporting perfect scores in all 3 domains. Most patients (58%) were completely satisfied with their shoulder appearance, 38% were more satisfied than not, 1 patient (4%) was neither satisfied nor dissatisfied, and no patients were dissatisfied. All patients except 1 who were interested in sports returned to sporting activities. PROs were not associated with bony remodeling (P > .05).

CONCLUSION

Teenaged patients with completely displaced clavicular fractures treated nonoperatively can expect excellent radiographic and clinical outcomes 5 years after injury.

Topology optimization of embracing fixator considering bone remodeling to mitigate stress shielding effect

The embracing fixator is one of the widely used internal fixation implants for bone fracture treatment. However, the stress shielding effect, a stress imbalance between the implant and bone caused by the mismatch in mechanical properties between them, is a significant and critical issue that may lead to treatment failure. Thus, it is of great importance to design the implant with an appropriate stiffness which can mitigate the stress shielding effect and provide the most favorable mechanical environment for bone healing and remodeling. To this end, a time-dependent topology optimization algorithm considering bone remodeling is proposed to optimize an embracing fixator used in the tibia fracture treatment. The change of callus density over time is simulated based on a bone remodeling model, and the callus density after a period of bone remodeling is selected to be the design objective to maximize. The design constraints include volume and the compliance of the whole fixation system. Meanwhile, the influence of the constraints on the regularity of material distribution of the optimized result is also studied. Besides, to test the effectiveness of the consideration of the bone remodeling in the embracing fixator design, a topology optimization concerning the minimization of the compliance of the entire system is also performed to make a comparison. Finally, the safety performance of optimized results considering bone remodeling is also verified by static analysis.

Evaluation of treatment processes in childhood fifth metacarpal bone (Boxer) fractures with QuickDASH scoring system

OBJECTIVE

Metacarpal fractures are one of the most common orthopedic injuries seen in emergency departments. Despite this, only a few data have been published about the epidemiology of metacarpal fractures. Simple radiographs are the standard imaging modality used to diagnose boxer fractures and determine the degree of angulation. Fractures and angulations should be identified by anteroposterior and lateral radiographs. The aim of this study was to follow the healing after closed reduction of fifth metacarpal neck fractures in a pediatric population using the QuickDASH score to determine whether it results in clinically significant improvement.

SUBJECTS AND METHODS

Between 2020 and 2022, our clinical record database for all metacarpal fractures treated at our institution was searched retrospectively every month. Children aged 18 years and younger with fifth metacarpal neck fractures treated with closed reduction and immobilization in our tertiary care emergency clinic were retrospectively reviewed.

RESULTS

52 pediatric patients were included in the study. The mean age at the time of injury was 14.04 years (SD=2.10, range=10-18 years). 92.30% (n=48) of the patients were male, and 7.70% (n=4) were female.

CONCLUSIONS

Accurate diagnosis and appropriate treatment are crucial in the management of childhood fifth metacarpal fractures to ensure proper healing, prevent long-term complications, and facilitate optimal functional recovery.

Biomechanical analysis of combi-hole locking compression plate during fracture healing: A numerical study of screw configuration

Locking compression plates (LCPs) have become a widely used option for treating femur bone fractures. However, the optimal screw configuration with combi-holes remains a subject of debate. The study aims to create a time-dependent finite element (FE) model to assess the impacts of different screw configurations on LCP fixation stiffness and healing efficiency across four healing stages during a complete fracture healing process. To simulate the healing process, we integrated a time-dependent callus formation mechanism into a FE model of the LCP with combi-holes. Three screw configuration parameters, namely working length, screw number, and screw position, were investigated. Increasing the working length negatively affected axial stiffness and healing efficiency (p < 0.001), while screw number or position had no significant impact (p > 0.01). The time-dependent model displayed a moderate correlation with the conventional time-independent model for axial stiffness and healing efficiency (ρ ≥ 0.733, p ≤ 0.025). The highest healing efficiency (95.2%) was observed in screw configuration C125 during the 4-8-week period. The results provide insights into managing fractures using LCPs with combi-holes over an extended duration. Under axial compressive loading conditions, the use of the C125 screw configuration can enhance callus formation during the 4-12-week period for transverse fractures. When employing the C12345 configuration, it becomes crucial to avoid overconstraint during the 4-8-week period.

Embracing ethical research: Implementing the 3R principles into fracture healing research for sustainable scientific progress

As scientific advancements continue to reshape the world, it becomes increasingly crucial to uphold ethical standards and minimize the potentially adverse impact of research activities. In this context, the implementation of the 3R principles-Replacement, Reduction, and Refinement-has emerged as a prominent framework for promoting ethical research practices in the use of animals. This article aims to explore recent advances in integrating the 3R principles into fracture healing research, highlighting their potential to enhance animal welfare, scientific validity, and societal trust. The review focuses on in vitro, in silico, ex vivo, and refined in vivo methods, which have the potential to replace, reduce, and refine animal experiments in musculoskeletal, bone, and fracture healing research. Here, we review material that was presented at the workshop "Implementing 3R Principles into Fracture Healing Research" at the 2023 Orthopedic Research Society (ORS) Annual Meeting in Dallas, Texas.

Unraveling IGFBP3-mediated m6A modification in fracture healing

BACKGROUND

This study investigates the role of IGFBP3-mediated m6A modification in regulating the miR-23a-3p/SMAD5 axis and its impact on fracture healing, aiming to provide insights into potential therapeutic targets.

METHODS

Utilizing fracture-related datasets, we identified m6A modification-related mRNA and predicted miR-23a-3p as a regulator of SMAD5. We established a mouse fracture healing model and conducted experiments, including Micro-CT, RT-qPCR, Alizarin Red staining, and Alkaline phosphatase (ALP) staining, to assess gene expression and osteogenic differentiation.

RESULTS

IGFBP3 emerged as a crucial player in fracture healing, stabilizing miR-23a-3p through m6A modification, leading to SMAD5 downregulation. This, in turn, inhibited osteogenic differentiation and delayed fracture healing. Inhibition of IGFBP3 partially reversed through SMAD5 inhibition, restoring osteogenic differentiation and fracture healing in vivo.

CONCLUSION

The IGFBP3/miR-23a-3p/SMAD5 axis plays a pivotal role in fracture healing, highlighting the relevance of m6A modification. IGFBP3's role in stabilizing miR-23a-3p expression through m6A modification offers a potential therapeutic target for enhancing fracture healing outcomes.