Inhibition of fracture healing

Polyene phosphatidylcholine promotes tibial fracture healing in rats by stimulating angiogenesis dominated by the VEGFA/VEGFR2 signaling pathway

One of the factors that predispose to fractures is liver damage. Interestingly, fractures are sometimes accompanied by abnormal liver function. Polyene phosphatidylcholine (PPC) is an important liver repair drug. We wondered if PPC had a role in promoting fracture healing. A rat model of tibial fracture was developed using the modified Einhorn model method. X-rays were used to detect the progression of fracture healing. Progress of ossification and angiogenesis at the fracture site were analyzed by Safranin O/fast green staining and CD31 immunohistochemistry. To investigate whether PPC has a direct angiogenesis effect, HUVECs were used. We performed MTT, wound healing, Transwell migration, and tube formation assays. Finally, RT-qPCR and Western blot analysis were used to study the underlying mechanism. The results showed that PPC significantly shortened the apparent recovery time of mobility in rats. PPC treatment significantly promoted the formation of cartilage callus, endochondral ossification, and angiogenesis at the fracture site. In vitro, PPC promoted the proliferative viability of HUVECs, their ability to heal wounds, and their ability to penetrate membranes in the Transwell apparatus and increased the tube formation of cells. The transcription of VEGFA, VEGFR2, PLCγ, RAS, ERK1/2 and MEK1/2 was significantly up regulated by PPC. Further, the protein level results demonstrated a significant increase in the expression of VEGFA, VEGFR2, MEK1/2, and ERK1/2 proteins. In conclusion, our findings suggest that PPC promotes angiogenesis by activating the VEGFA/VEGFR2 and downstream signaling pathway, thereby accelerating fracture healing.

Current Management of Acute and Posttraumatic Critical Bone Defects

SUMMARY

Limb reconstruction in patients with critical-sized bone defects remains a challenge due to the availability of various technically demanding treatment options and a lack of standardized decision algorithms. Although no consensus exists, it is apparent from the literature that the combination of patient, surgeon, and institutional collaborations is effective in providing the most efficient care pathway for these patients. Success relies on choosing a particular surgical approach that manages infection, soft tissue defects, stability, and alignment. Recent systematic reviews demonstrate high success rates with the following management options: Ilizarov bone transport, Masquelet (induced membrane) technique, cancellous bone grafting, and vascularized bone grafts.

NSAID use in orthopedic surgery: A review of current evidence and clinical practice guidelines

Nonsteroidal anti-inflammatory drugs (NSAIDs) are a valuable class of medications for orthopedic surgeons and often play a pivotal role in pain control. However, there are many common stipulations resulting in avoidance of its use in the treatment of musculoskeletal disease. This review summarizes the mechanism of action of NSAIDs as well as provides an overview of commonly used NSAIDs and the differences between them. It provides a concise summary on the osseous effects of NSAIDs with regard to bone healing and heterotopic ossification. Most of all, it serves as a guide or reference for orthopedic providers when counseling patients on the risks and benefits of NSAID use, as it addresses the common stipulations encountered: "It irritates my stomach," "I have a history of bariatric surgery," "I'm already on a blood thinner," "I've had a heart attack," and "I've got kidney problems" and synthesizes both current research and society recommendations regarding safe use and avoidance of NSAIDs.

Refinement in Post-Operative Care for Orthopaedic Models: Implementing a Sheep Walking Cast (SWC) for Effective Tibial Fracture Management

In the healthcare system, lower leg fractures remain relevant, incurring costs related to surgical treatment, hospitalization, and rehabilitation. The duration of treatment may vary depending on the individual case and its severity. Casting as a post-surgical fracture treatment is a common method in human and experimental veterinary medicine. Despite the high importance of sheep in preclinical testing materials for osteosynthesis, there is no standardised cast system ensuring proper stabilisation and functionality of hind limbs during the healing of tibia fractures or defects. Existing treatment approaches for tibial osteosynthesis in laboratory animal science include sling hanging, external fixators, or former Achilles tendon incision. These methods restrict animal movement for 4-6 weeks, limit species-typical behaviour, and impact social interactions. Our pilot study introduces a Standardised Walking Cast (SWC) for sheep, enabling immediate physiological movement post surgery. Seven Rhone sheep (female, 63.5 kg ± 6.45 kg) each with a single tibia defect (6 mm mechanical drilled defect) underwent SWC application for 4 weeks after plate osteosynthesis. The animals bore weight on their operated leg from day one, exhibiting slight lameness (grade 1-2 out of 5). Individual step lengths showed good uniformity (average deviation: 0.89 cm). Group housing successfully started on day three after surgery. Weekly X-rays and cast changes ensured proper placement, depicting the healing process. This study demonstrates the feasibility of using an SWC for up to 72 kg of body weight without sling hanging via ceiling mounting or external fixation techniques. Allowing species-typical movement and social behaviour can significantly improve the physiological behaviour of sheep in experiments, contributing to refinement.

Metacarpal and Phalangeal Nonunions

The majority of phalangeal and metacarpal fractures will proceed to union when appropriately treated. However, when a nonunion does occur, it can lead to significant functional impairment for patients and societal costs. Operative intervention is typically required in these cases, but the technique can vary depending on each individual patient scenario. This article provides an overview of nonunions of the metacarpals and phalanges in the hand, including incidence, risk factors, current treatment options, and postoperative care.

Complication rates and modes of short and medium-term failure in Motec total wrist arthroplasty: an international cohort study

The aim of this study was to analyse the short- and medium-term complications of the Motec total wrist arthroplasty (TWA). Identifying exact modes of failure and their causes should allow surgeons to avoid or mitigate these risks in the future. Retrospective analysis of prospectively collected data from six hand surgeons at five international centres provided details of 171 Motec TWAs. The mean follow-up was 5.8 years (range 18 months to 12 years). There were 33 (19%) complications within our cohort, with a revision rate of 8.2% (14 revisions). There was no difference in complication rates between metal-on-metal and metal-on-polymer articulations. Failure of osseointegration was the most common complication. Problems with soft tissue balancing, implant impingement related osteolysis, bony impingement and metacarpal fracture were found to be other preventable causes of failure in this series. Elimination of these preventable complications will improve survival rates for this implant.Level of evidence: IV.

Myosin heavy chain 2 (MYH2) expression in hypertrophic chondrocytes of soft callus provokes endochondral bone formation in fracture

AIMS

Muscle-bone interactions during fracture healing are rarely known. Here we investigated the presence and significance of myosin heavy chain 2 (MYH2), a component of myosin derived from muscles, in fracture healing.

MAIN METHODS

We collected five hematoma and seven soft callus tissues from patients with distal radius fractures patients, randomly selected three of them, and performed a liquid chromatography-mass spectrometry (LC-MS) proteomics analysis. Proteomic results were validated by histological observation, immunohistochemistry, and immunofluorescence for MYH2 expression. These findings were further confirmed in a murine femoral fracture model in vivo and investigated using various methods in vitro.

KEY FINDINGS

The LC-MS proteomics analysis showed that MYH proteins were enriched in human soft calluses compared to hematoma. Notably, MYH2 protein is upregulated as high rank in each soft callus. The histological examination showed that MYH2 expression was elevated in hypertrophic chondrocytes within the human soft callus. Consistent with human data, Myh2 were significantly co-localized with Sox9 in hypertrophic chondrocytes of murine femoral fracture, in comparison to pre-hypertrophic and proliferating chondrocytes. Soluble MYH2 protein treatment increased MMP13 and RUNX2 expression in chondrocytes. In soluble MYH2 treatment, proliferation of chondrocytes was not altered, but the osteogenic and chondrogenic features of chondrocytes increased and decreased during differentiation, respectively.

SIGNIFICANCE

These findings indicate the potential of soluble MYH2 protein as a promising therapeutic strategy for promoting endochondral bone formation in chondrocytes following fracture.

Parathyroid hormone stimulates bone regeneration in an atrophic non-union model in aged mice

BACKGROUND

Non-union formation still represents a major burden in trauma and orthopedic surgery. Moreover, aged patients are at an increased risk for bone healing failure. Parathyroid hormone (PTH) has been shown to accelerate fracture healing in young adult animals. However, there is no information whether PTH also stimulates bone regeneration in atrophic non-unions in the aged. Therefore, the aim of the present study was to analyze the effect of PTH on bone regeneration in an atrophic non-union model in aged CD-1 mice.

METHODS

After creation of a 1.8 mm segmental defect, mice femora were stabilized by pin-clip fixation. The animals were treated daily with either 200 mg/kg body weight PTH 1-34 (n = 17) or saline (control; n = 17) subcutaneously. Bone regeneration was analyzed by means of X-ray, biomechanics, micro-computed tomography (µCT) imaging as well as histological, immunohistochemical and Western blot analyses.

RESULTS

In PTH-treated animals bone formation was markedly improved when compared to controls. This was associated with an increased bending stiffness as well as a higher number of tartrate-resistant acid phosphatase (TRAP)-positive osteoclasts and CD31-positive microvessels within the callus tissue. Furthermore, PTH-treated aged animals showed a decreased inflammatory response, characterized by a lower number of MPO-positive granulocytes and CD68-positive macrophages within the bone defects when compared to controls. Additional Western blot analyses demonstrated a significantly higher expression of cyclooxygenase (COX)-2 and phosphoinositide 3-kinase (PI3K) in PTH-treated mice.

CONCLUSION

Taken together, these findings indicate that PTH is an effective pharmacological compound for the treatment of non-union formation in aged animals.

Osteogenesis Stimulator Devices Reduce Surgical Intervention, Opioid Utilization, and Overall Costs in Patients with Fracture Nonunions

Background

Approximately 10% of fractures result in delayed union or nonunion. These cases result in pain and disability as well as increased utilization of healthcare resources such as pain medication, physical therapy, and subsequent surgery. Osteogenesis stimulator devices are a safe and low-cost, non-invasive option to aid healing in nonunion cases.

Objective

Study objectives aimed to evaluate real-world data of osteogenesis stimulator device usage in a variety of healthcare utilization endpoints including surgical intervention for nonunion, pain medication use, and overall healthcare costs. Data were stratified into three groups: the Stim Device group and the No Stim and Surgical control groups.

Methods

A retrospective analysis of a large claims-based database was conducted. The database was queried for adult patients having a diagnosis of nonunion, with evidence of a prior fracture in the previous 180 days (n = 11,010). The osteogenesis stimulator group (Stim Device group, n = 1,628) was defined as those patients having at least one claim for an osteogenesis stimulator in the period 90 to 180 days following fracture and up to 60 days following the nonunion diagnosis. The control group (No Stim group, n = 9,382) had a nonunion diagnosis with evidence of a fracture in the prior 180 days but did not receive a device. A total of 1,751 patients from the No Stim group were sub-grouped into surgical/operative controls (No Stim - Surgical group).

Results

Stim Device patients showed lower rates of surgical intervention for their bone nonunion compared to the No Stim patients (214/1,628, 13.1% vs. 1,751/9,382, 18.7%, p < 0.001). Stim Device patients had lower rates of opioid utilization post-index compared to No Stim patients (948/1,628, 58.2% vs. 6,359/9,382, 67.8%, p < 0.001). Overall healthcare costs were significantly reduced in the Stim Device group ($21,654) compared with No Stim ($29,101; p < 0.001) and Surgical ($35,914; p < 0.001) control groups.

Conclusion

The results show that bone growth stimulator devices have a positive individual and societal impact on treating patients with fracture nonunions.

Effects of dynamization timing and degree on bone healing of different fracture types

Dynamization, that is, increasing interfragmentary movement (IFM) by reducing fixation stiffness from a rigid to a more flexible state, has been successfully used in clinical practice to promote fracture healing. However, it remains unclear how dynamization timing and degree affect bone healing of different fracture types. Finite element models of tibial fractures based on the OTA/AO classification (Simple: A1-Spiral, A2-Oblique, A3-Transverse; Wedge: B2-Spiral, B3-Fragmented; Complex: C2-Segment, C3-Irregular), in combination with fuzzy logic-based mechano-regulatory tissue differentiation algorithms, were used to simulate the healing process when dynamization of varied degrees (dynamization coefficient or DC = 0-0.9; 0.9 represents 90% reduction in the fixation stiffness relative to a rigid fixation) were applied at different time points after fracture. The fuzzy logic-based algorithms have been validated with a preclinical animal model. The results showed that the healing responses of type A fractures were more sensitive to the changes in dynamization degree and timing comparing with type B or C fractures. Additionally, the optimal dynamization regime for each fracture type was different. For type A fractures, a moderate dynamization degree (e.g., DC = 0.5) applied after Week 1 promoted the recovery of biomechanical integrity. For type B and C fractures, the effective dynamization included a greater dynamization degree (DC = 0.7) applied after Week 2. Our results further demonstrated that the fracture morphology affected interfragmentary strain environments within the callus, leading to varied healing results for different fracture types. These results suggest that the effects of dynamization are highly dependent of the fracture types. Therefore, specific dynamization strategies should be chosen for different fracture types to achieve optimal healing outcomes.

Bisphosphonate conjugation enhances the bone-specificity of NELL-1-based systemic therapy for spaceflight-induced bone loss in mice

Microgravity-induced bone loss results in a 1% bone mineral density loss monthly and can be a mission critical factor in long-duration spaceflight. Biomolecular therapies with dual osteogenic and anti-resorptive functions are promising for treating extreme osteoporosis. We previously confirmed that NELL-like molecule-1 (NELL-1) is crucial for bone density maintenance. We further PEGylated NELL-1 (NELL-polyethylene glycol, or NELL-PEG) to increase systemic delivery half-life from 5.5 to 15.5 h. In this study, we used a bio-inert bisphosphonate (BP) moiety to chemically engineer NELL-PEG into BP-NELL-PEG and specifically target bone tissues. We found conjugation with BP improved hydroxyapatite (HA) binding and protein stability of NELL-PEG while preserving NELL-1's osteogenicity in vitro. Furthermore, BP-NELL-PEG showed superior in vivo bone specificity without observable pathology in liver, spleen, lungs, brain, heart, muscles, or ovaries of mice. Finally, we tested BP-NELL-PEG through spaceflight exposure onboard the International Space Station (ISS) at maximal animal capacity (n = 40) in a long-term (9 week) osteoporosis therapeutic study and found that BP-NELL-PEG significantly increased bone formation in flight and ground control mice without obvious adverse health effects. Our results highlight BP-NELL-PEG as a promising therapeutic to mitigate extreme bone loss from long-duration microgravity exposure and musculoskeletal degeneration on Earth, especially when resistance training is not possible due to incapacity (e.g., bone fracture, stroke).

Sildenafil, a phosphodiesterase-5 inhibitor, stimulates angiogenesis and bone regeneration in an atrophic non-union model in mice

Non-union formation represents a major complication in trauma and orthopedic surgery. The phosphodiesterase-5 (PDE-5) inhibitor sildenafil has been shown to exert pro-angiogenic and pro-osteogenic effects in vitro and in vivo. Therefore, the aim of the present study was to analyze the impact of sildenafil in an atrophic non-union model in mice. After creation of a 1.8 mm segmental defect, mice femora were stabilized by pin-clip fixation. Bone regeneration was analyzed by means of X-ray, biomechanics, photoacoustic and micro-computed tomography (µCT) imaging as well as histological, immunohistochemical and Western blot analyses at 2, 5 and 10 weeks after surgery. The animals were treated daily with either 5 mg/kg body weight sildenafil (n = 35) or saline (control; n = 35) per os. Bone formation was markedly improved in defects of sildenafil-treated mice when compared to controls. This was associated with a higher bending stiffness as well as an increased number of CD31-positive microvessels and a higher oxygen saturation within the callus tissue. Moreover, the bone defects of sildenafil-treated animals contained more tartrate-resistant acid phosphatase (TRAP)-positive osteoclasts and CD68-positive macrophages and exhibited a higher expression of the pro-angiogenic and pro-osteogenic markers cysteine rich protein (CYR)61 and vascular endothelial growth factor (VEGF) when compared to controls. These findings demonstrate that sildenafil acts as a potent stimulator of angiogenesis and bone regeneration in atrophic non-unions.

Factors Associated With Amputation Following Ankle Fracture Surgery

Patients with diabetes mellitus (DM) are at increased risk of complications following ankle fracture surgery. Previous research suggests that patients of low socioeconomic status are at increased risk of amputation following orthopedic complications. The purpose of this research was to determine if low socioeconomic status increases risk of below-knee amputation (BKA) following ankle fractures among patients with DM. The National Inpatient Sample (NIS) was queried from 2010 to 2014 to identify 125 diabetic patients who underwent ankle fracture surgical fixation followed by BKA. Two cohorts (BKA vs no BKA) and a multivariate logistic regression model were created to compare the effects of independent variables, including age, sex, race, primary payer, median household income by ZIP code, hospital location/teaching status, and comorbidities. The most predictive variables for BKA were concomitant peripheral vascular disease (odds ratio [OR] 5.35, 95% confidence interval [CI] 3.51-8.15), history of chronic diabetes-related medical complications (OR 3.29, CI 2.16-5.01), age in the youngest quartile (OR 2.54, CI 1.38-4.67), and male sex (OR 2.28, CI 1.54-3.36). Patient race and median household income were not significantly associated with BKA; however, risk of BKA was greater among patients with Medicaid (OR 2.23, CI 1.09-4.53) or Medicare (OR 1.85, CI 1.03-3.32) compared to privately insured patients. Diabetic inpatients with Medicaid insurance are at over twice the odds of BKA compared to privately insured patients following ankle fracture. Furthermore, peripheral vascular diseases, uncontrolled diabetes, younger age, and male sex each independently increase risk of BKA.

Fractures in elderly mice demonstrate delayed ossification of the soft callus: a cellular and radiographic study

OBJECTIVES

The aim of this study was to assess the cellular age-related changes in fracture repair and relate these to the observed radiographic assessments at differing time points.

METHODS

Transverse traumatic tibial diaphyseal fractures were created in 12-14 weeks old (young n = 16) and 18 months old (elderly n = 20) in Balb/C wild mice. Fracture calluses were harvested at five time points from 1 to 35 days post fracture for histomorphometry (percent of cartilage and bone), radiographic analysis (total callus volume, callus index, and relative bone mineral content).

RESULTS

The elderly mice produced an equal amount of cartilage when compared to young mice (p > 0.08). However, by day 21 there was a significantly greater percentage of bone at the fracture site in the young group (mean percentage 50% versus 11%, p < 0.001). It was not until day 35 when the elderly group produced a similar amount of bone compared to the young group at 21 days (50% versus 53%, non-significant (ns)). The callus area and callus index on radiographic assessment was not significantly different between young and elderly groups at any time point. Relative bone mineral content was significantly greater in the young group at 14 days (545.7 versus -120.2, p < 0.001) and 21 days (888.7 versus 451.0, p < 0.001) when compared to the elderly group. It was not until day 35 when the elderly group produced a similar relative bone mineral content as the young group at 21 days (888.7 versus 921.8, ns).

CONCLUSIONS

Elderly mice demonstrated a delay in endochondral ossification which was associated with a decreased relative bone mineral content at the fracture site and may help assess these cellular changes in a clinical setting.

Risk Factors for Reoperation to Promote Union in 1111 Distal Femur Fractures

OBJECTIVES

To identify modifiable and nonmodifiable risk factors for reoperation to promote union after distal femur fracture.

DESIGN

Multicenter retrospective cohort study.

SETTING

Ten Level-I trauma centers.

PATIENTS/PARTICIPANTS

Patients with OTA/AO 33A or C distal femur fractures (n = 1111).

INTERVENTION

Surgical fixation of distal femur fracture. Fixation constructs were classified as lateral plate, dual plate, nail, or nail plate combination.

MAIN OUTCOME MEASUREMENTS

The outcome of interest was unplanned reoperation to promote union.

RESULTS

There was an 11% (121/1111) rate of unplanned reoperation to promote union. In the multivariate analysis, predictive factors included body mass index [odds ratio (OR) = 1.18; 95% confidence interval (CI), 1.06-1.32; P < 0.01], intra-articular fracture (OR = 1.57; 95% CI, 1.01-2.45; P = 0.04), type III open injury (OR = 2.29; 95% CI, 1.41-3.72; P < 0.01), the presence of medial comminution (OR = 1.85; 95% CI, 1.14-3.06; P = 0.01), and medial translation on postoperative radiographs (OR = 1.23 per one 10th of condylar width; 95% CI, 1.01-1.48; P = 0.03). Construct type was not significantly predictive.

CONCLUSIONS

Eleven percent of distal femur fractures underwent unplanned reoperation to promote union. Body mass index, intra-articular fracture, type III open injury, medial comminution, and medial translation on postoperative radiographs were predictive factors. Construct type was not associated with unplanned reoperation; however, this conclusion was limited by small numbers in the dual plate and nail plate groups.

LEVEL OF EVIDENCE

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

Bone Grafting Outcomes in Smokers Undergoing High Tibial Osteotomy: A Systematic Review

This systematic review summarises the findings in the literature available to show outcomes of high tibial osteotomy (HTO) with bone grafting in smokers. It also studies the trend of complications, outcome measures used and overall outcomes like union, non-union or the need to perform revision surgeries. The aim is to find out if HTO done with bone grafting improves outcomes in smokers. Articles were shortlisted using Population, Intervention, Control, and Outcomes (PICO) search design and quality assessment was completed using Jadad, STROBE (Strengthening the Reporting of Observational studies in Epidemiology), Delphi, and Critical Appraisal Skills Program (CASP) followed by data extraction by two independent authors. There was union in 97.6% of smokers who received HTO with bone grafting. A case of non-union was treated with removal of metalwork and distraction osteogenesis. Three cases of unknown demographics had arthroplasty in the time frame from HTO with bone grafting to follow up. The commonest complication post surgery was metalwork causing soft tissue irritation and lateral proximal tibial cortex fracture. Following this review we can conclude that HTO with bone grafting could be considered as an option to achieve better outcomes in smokers. Bone grafting helps healing across osteotomy sites in smokers whose healing potential is poor. Autogenous Iliac crest bone grafting is ideal due to its osteoinductive and osteoconductive properties, but has the disadvantage of donor site morbidity.

Exosomes Derived from Adipose Stem Cells Enhance Bone Fracture Healing via the Activation of the Wnt3a/β-Catenin Signaling Pathway in Rats with Type 2 Diabetes Mellitus

Nonunion and delayed union are common complications of diabetes mellitus that pose a serious health threat to people. There are many approaches that have been used to improve bone fracture healing. Recently, exosomes have been regarded as promising medical biomaterials for improving fracture healing. However, whether exosomes derived from adipose stem cells can promote bone fracture healing in diabetes mellitus remains unclear. In this study, adipose stem cells (ASCs) and exosomes derived from adipose stem cells (ASCs-exos) are isolated and identified. Additionally, we evaluate the in vitro and in vivo effects of ASCs-exos on the osteogenic differentiation of bone marrow mesenchymal stem cells (BMSCs) and bone repair and the regeneration in a rat model of nonunion via Western blotting, immunofluorescence assay, ALP staining, alizarin red staining, radiographic examination and histological analysis. Compared with controls, ASCs-exos promoted BMSC osteogenic differentiation. Additionally, the results of Western blotting, radiographic examination and histological analysis show that ASCs-exos improve the ability for fracture repair in the rat model of nonunion bone fracture healing. Moreover, our results further proved that ASCs-exos play a role in activating the Wnt3a/β-catenin signaling pathway, which facilitates the osteogenic differentiation of BMSCs. All these results show that ASCs-exos enhance the osteogenic potential of BMSCs by activating the Wnt/β-catenin signaling pathway, and also facilitate the ability for bone repair and regeneration in vivo, which provides a novel direction for fracture nonunion in diabetes mellitus treatment.

Symptomatic Hammertoes Treatment Comparison: Peg-in-Hole Arthrodesis Versus End-to-End Screw Fixation

Proximal interphalangeal (PIP) arthrodesis technique utilizing the peg-in-hole arthrodesis was founded to avoid the use of retained internal fixation implants and thereby potentially decrease the concern of hardware complication. The specific aim of this study was to report the complication rates of the modified peg-in-hole arthrodesis technique and the end-to-end arthrodesis with single screw fixation technique for correcting symptomatic hammertoe deformities in lesser digits. This retrospective chart review included patients who underwent surgical hammertoe correction of lesser digits between the dates of January 2012 and December 2019. Patient demographic data and charts were reviewed to evaluate need for revision including screw/pin removal and complications related to corrective surgery. Five hundred ninety-three symptomatic hammertoe deformity cases (443 female, 150 male) were identified, with 113 cases (88 female, 25 male) treated with peg-in-hole arthrodesis technique and 480 cases (355 female, 125 male) treated with end-to-end arthrodesis with a single screw technique. The deformity recurrence rate was not significantly different between the two techniques (peg-in-hole: 10%, end-to-end: 13%, p = .428). There were 97 cases with postoperative complications that required re-operation (peg-in-hole: 7 cases, end-to-end: 90 cases) with the majority detected at <6 months. There was no statistically significant difference in reoperation rate between the peg-in-hole technique and the end-to-end arthrodesis technique reoperated with reasons excluding simple screw removal (p = .068). This study tended to show these two arthrodesis techniques have equivalent risks and similar success in bone healing; however, the peg-in-hole arthrodesis technique offers an advantage that does not result in retained hardware.

Osteoimmunology: The effect of autoimmunity on fracture healing and skeletal analysis

Understanding factors that affect bone response to trauma is integral to forensic skeletal analysis. It is essential in forensic anthropology to identify if impaired fracture healing impacts assessment of post-traumatic time intervals and whether a correction factor is required. This paper presents a synthetic review of the intersection of the literature on the immune system, bone biology, and osteoimmunological research to present a novel model of interactions that may affect fracture healing under autoimmune conditions. Results suggest that autoimmunity likely impacts fracture healing, the pathogenesis however, is under researched, but likely multifactorial. With autoimmune diseases being relatively common, significant clinical history should be incorporated when assessing skeletal remains. Future research includes the true natural healing rate of bone; effect of autoimmunity on this rate; variation of healing with different autoimmune diseases; and if necessary, development of a correction factor on the natural healing rate to account for impairment in autoimmunity.

Disorganization and Musculoskeletal Diseases: Novel Insights into the Enigma of Unexplained Bone Abnormalities and Fragility Fractures

PURPOSE OF REVIEW

Describe the potential contribution of disorganized tissue to the pathogenesis of bone abnormalities and fractures. Especially, fractures that are unexplained by bone loss (osteoporosis) or structural deterioration.

RECENT FINDINGS

Currently, bone fragility is primarily viewed as due to loss, or decay (osteoporosis). However, it is also acknowledged that this view is limited because it does not explain many fractures or abnormalities such as necrosis, sclerosis, or infarcts. Atypical femoral fractures (AFFs) during antiresorptive therapy are an example. Hence, it is proposed that another distinct mechanism is responsible for bone diseases. A remarkable bone property distinct from mass and decay is the organization (arrangement) of its components. Components must be perfectly assembled or well-stacked to ensure "the right amount of bone, at the right place". Disorganization is an aberration that is conspicuous in many diseases, more so in conditions poorly associated with bone mass and decay such as osteogenesis imperfecta, hypophosphatasia, and AFFs. However, despite the likely critical role of disorganization, this feature has received limited clinical attention. This review focuses on the potential contribution of disorganization to bone in health and diseases. Particularly, we propose that disorganization, by causing ineffective transfer of loads, may produce not only bone abnormalities (pain, necrosis, infarct, sclerosis, delayed healing) but also fractures, especially AFFs or stress fractures. A disorganized element is one that is where it shouldn't be (improperly stacked elements). Hence, disorganization can be measured by quantifying the extent to which a tissue (pixel within an image) is at an incorrect location.

General Considerations About Foot and Ankle Arthrodesis. Any Way to Improve Our Results?

Nonunion and adjacent joint osteoarthritis (OA) are known complications after a fusion procedure, and foot and ankle surgeons are commonly exposed to such disabling complications. Determining who is at risk of developing nonunion is essential to reducing nonunion rates and improving patient outcomes. Several evidenced-based modifiable risk factors related to adverse outcomes after foot and ankle arthrodesis have been identified. Patient-related risk factors that can be improved before surgery include smoking cessation, good diabetic control (HbAc1 <7%) and vitamin D supplementation. Intraoperatively, using less invasive techniques, avoiding joint preparation with power tools, using bone grafts or orthobiologics in more complex cases, high-risk patients, nonunion revision surgeries, and filling in bone voids at the arthrodesis site should be considered. Postoperatively, pain management with NSAIDs should be limited to a short period (<2 weeks) and avoided in high-risk patients. Furthermore, early postoperative weight-bearing has shown to be beneficial, and it does not seem to increase postoperative complications. The incidence of surrounding joint OA after foot and ankle fusion seems to increase progressively with time. Owing to its progression and high probability of being symptomatic, patients must be informed consequently, as they may require additional joint fusions, resulting in further loss of ankle/foot motion. In patients with symptomatic adjacent joint OA and unsatisfactory results after an ankle arthrodesis, conversion to total ankle arthroplasty (TAA) has become a potential option in managing these complex and challenging situations.

Diagnostic Imaging Studies on Local and Systemic Erythropoietin Application for Promoting Bone Regeneration in Rat Calvarial Defects

The purpose of this study was to compare the effects of local and systemic application of recombinant human erythropoietin (rhEPO) on the healing of rat calvarial defects. Twenty-four male skeletally-mature Wistar rats were used. Two bone 5 mm critical size defects were created in calvarial bones of each rat. In rats from experimental group I (n = 12), EPO was applied locally on a collagen cone in left defects, whereas a collagen cone soaked with physiological saline was placed in right defects. The rats from experimental group II were injected once intraperitoneally with 4900 IU/kg EPO; a collagen cone was only placed in left defects, whereas the right defects were left empty. The systemic effect of EPO treatment was monitored by haematological analyses on days 0, 30 and 90. Bone healing was monitored via radiography and computed tomography on the same time intervals. The results demonstrated that local EPO application had no significant effect on haemopoiesis, unlike the systemic application. At the same time, it resulted in new bone formation and therefore, could be successfully used as a means of promoting bone regeneration.

Identifying Risk Factors for Nonunion of the Modified Lapidus Procedure for the Correction of Hallux Valgus

There is a paucity of literature characterizing risk factors for nonunion associated with the modified Lapidus procedure for correction of hallux valgus. The purpose of this study was to evaluate risk factors associated with nonunion for Lapidus bunionectomies. Patients who underwent modified Lapidus procedure from 2009 to 2018 were retrospectively reviewed. Patient's age, sex, body mass index, prior bunionectomy, history of tobacco use, presence of diabetes mellitus or hypothyroidism, and fixation method were recorded along with pre- and postoperative radiographic parameters. A multiple logistic regression analysis was implemented to estimate the odds of nonunion. Of the 222 patients who met inclusion criteria, nonunion with modified Lapidus procedure was observed in 20 patients (9.01%). Odds of nonunion with modified Lapidus procedure were greater for patients who had undergone previous bunionectomy (odds ratio [OR] = 3.957, 95% confidence interval [CI]: 1.021-15.338), as body mass index increased (OR = 1.091, 95% CI: 1.018-1.170), and as preoperative HV angle increased (OR = 1.108, 95% CI: 1.020-1.203). Odds of nonunion were lower for patients as preoperative intermetatarsal angle increased (OR = 0.739, 95% CI: 0.580-0.941). No significant increased odds of nonunion were found between fixation methods.

The effect of anti-retroviral therapy on fracture healing : an in vivo animal model

AIMS

A number of anti-retroviral therapies (ART) have been implicated in potentially contributing to HIV-associated bone disease. The aim of this study was to evaluate the effect of combination ART on the fracture healing process.

METHODS

A total of 16 adult male Wistar rats were randomly divided into two groups (n = eight each): Group 1 was given a combination of Tenfovir 30 mg, Lamivudine 30 mg, and Efavirenz 60 mg per day orally, whereas Group 2 was used as a control. After one week of medication preload, all rats underwent a standardized surgical procedure of mid-shaft tibial osteotomy fixed by intramedullary nail with no gap at the fracture site. Progress in fracture healing was monitored regularly for eight weeks. Further evaluations were carried out after euthanasia by micro-CT, mechanically and histologically. Two blinded orthopaedic surgeons used the Radiological Union Scoring system for the Tibia (RUST) to determine fracture healing.

RESULTS

The fracture healing process was different between the two groups at week 4 after surgery; only two out of eight rats showed full healing in Group 1 (ART-treated), while seven out of eight rats had bone union in Group 2 (control) (p = 0.040). However, at week eight postoperatively, there was no statistical difference in bone healing; seven out of eight progressed to full union in both groups.

CONCLUSION

This study demonstrated that combination ART resulted in delayed fracture healing at week 4 after surgery in rats, but did not result in the development of nonunion.Cite this article: Bone Joint Res 2022;11(8):585-593.

Hypoxia Preconditioned Serum (HPS) Promotes Osteoblast Proliferation, Migration and Matrix Deposition

Interest in discovering new methods of employing natural growth factor preparations to promote bone fracture healing is becoming increasingly popular in the field of regenerative medicine. In this study, we were able to demonstrate the osteogenic potential of hypoxia preconditioned serum (HPS) on human osteoblasts in vitro. Human osteoblasts were stimulated with two HPS concentrations (10% and 40%) and subsequently analyzed at time points of days 2 and 4. In comparison to controls, a time- and dose-dependent (up to 14.2× higher) proliferation of osteoblasts was observed after 4 days of HPS-40% stimulation with lower lactate dehydrogenase (LDH)-levels detected than controls, indicating the absence of cytotoxic/stress effects of HPS on human osteoblasts. With regards to cell migration, it was found to be significantly faster with HPS-10% application after 72 h in comparison to controls. Further osteogenic response to HPS treatment was evaluated by employing culture supernatant analysis, which exhibited significant upregulation of OPG (Osteoprotegerin) with higher dosage (HPS-10% vs. HPS-40%) and longer duration (2 d vs. 4 d) of HPS stimulation. There was no detection of anti-osteogenic sRANKL (soluble Receptor Activator of NF-κB Ligand) after 4 days of HPS stimulation. In addition, ALP (alkaline phosphatase)-enzyme activity, was found to be upregulated, dose-dependently, after 4 days of HPS-40% application. When assessing ossification through Alizarin-Red staining, HPS dose-dependently achieved greater (up to 2.8× higher) extracellular deposition of calcium-phosphate with HPS-40% in comparison to controls. These findings indicate that HPS holds the potential to accelerate bone regeneration by osteogenic promotion of human osteoblasts.

Postmortem and Antemortem Forensic Assessment of Pediatric Fracture Healing from Radiographs and Machine Learning Classification

Simple Summary

Being able to estimate from X-rays alone how long ago a child’s bone was fractured is important for prosecuting suspected child abuse of living or dead children. This estimate can also help identify a child when all that remains are bones. Experts use various indicators to make these estimates of the age of healing and fully healed fractures, in living and deceased persons, even years after the injury occurred. However, it is not a precise science. We proposed a method using a new combination of indicators to classify fracture healing in children and adolescents. We tested its accuracy with a public database of X-rays of children’s fractures taken during the treatment and healing process. We used part of the X-ray database for training artificial intelligence (AI, or machine learning) programs to classify stages of bone healing when using our new system. We used another portion of the same database to test the performance of the AI system that had been trained with our new classification system. Our new system addresses certain classification ambiguities of a currently used system and is similar in accuracy.

Abstract

A timeline of pediatric bone healing using fracture healing characteristics that can be assessed solely using radiographs would be practical for forensic casework, where the fracture event may precede death by days, months, or years. However, the dating of fractures from radiographs is difficult, imprecise, and lacks consensus, as only a few aspects of the healing process are visible on radiographs. Multiple studies in both the clinical and forensic literature have attempted to develop a usable scale to assess pediatric bone healing on radiographs using various healing characteristics. In contrast to the orthopedic definition, a fracture in forensic casework is only considered to be healed when the area around the fracture has been remodeled to the point that the fracture is difficult to detect on a radiograph or on the surface of the bone itself, a process that can take several years. We subjectively assessed visible characteristics of healing in radiograms of fractures occurring in 942 living children and adolescents. By dividing these assessments into learning and test (validation) sets, the accuracy of a newly proposed fracture healing scale was compared to a previous study. Two machine learning models were used to test predictions of the new scale. All three models produced similar estimates with substantial imprecision. Results corroborate the Malone model with an independent dataset and support the efficacy of using less complex models to estimate fracture age in children.

Outcomes After Operative Reconstruction of Symptomatic Rib Nonunions

OBJECTIVE

To assess the outcomes of patients after rib nonunion reconstruction.

DESIGN

Retrospective case series.

SETTING

Level 1 trauma center.

PATIENTS/PARTICIPANTS

Between January 2007 and August 2019, 25 consecutive patients with 51 nonunions with disabling pain or chronic instability were treated for nonunited rib fractures.

INTERVENTION

Rib nonunion reconstructions performed using plate and screw fixation, recannalizing the medullary canal and augmented with autogenous iliac crest bone graft.

MAIN OUTCOME MEASUREMENTS

Patient demographics, mechanism of injury, number of rib nonunions, and postoperative radiographs were assessed. Satisfaction, patient-reported complications, return to occupation and activity, and general health measures were captured using patient questionnaires.

RESULTS

In 25 patients, 51 painful rib nonunions were surgically treated. The average length from injury to surgical rib reconstruction was 25.1 months (range = 3-118 months; median = 12 months). Follow-up was obtained in 18 of 25 patients (72%) with a mean of 46.1 months (range = 13-139 months). All ribs achieved radiographic union at an average of 12.3 weeks (range = 8-24 weeks) after surgery. Sixteen of 18 patients (89%) reported satisfaction with surgery and 15 patients (83%) reported mild to no pain at final follow-up. Five patients had complications that all resolved after subsequent treatment.

CONCLUSIONS

Successful treatment of symptomatic rib nonunion is possible using rib plates in conjunction with bone grafting and has high union rates, satisfactory results, and limited complications.

LEVEL OF EVIDENCE

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

Effect of Intramedullary Nailing Patterns on Interfragmentary Strain in a Mouse Femur Fracture: A Parametric Finite Element Analysis

Delayed long bone fracture healing and nonunion continue to be a significant socioeconomic burden. While mechanical stimulation is known to be an important determinant of the bone repair process, understanding how the magnitude, mode, and commencement of interfragmentary strain (IFS) affect fracture healing can guide new therapeutic strategies to prevent delayed healing or nonunion. Mouse models provide a means to investigate the molecular and cellular aspects of fracture repair, yet there is only one commercially available, clinically-relevant, locking intramedullary nail (IMN) currently available for studying long bone fractures in rodents. Having access to alternative IMNs would allow a variety of mechanical environments at the fracture site to be evaluated, and the purpose of this proof-of-concept finite element analysis study is to identify which IMN design parameters have the largest impact on IFS in a murine transverse femoral osteotomy model. Using the dimensions of the clinically relevant IMN as a guide, the nail material, distance between interlocking screws, and clearance between the nail and endosteal surface were varied between simulations. Of these parameters, changing the nail material from stainless steel (SS) to polyetheretherketone (PEEK) had the largest impact on IFS. Reducing the distance between the proximal and distal interlocking screws substantially affected IFS only when nail modulus was low. Therefore, IMNs with low modulus (e.g., PEEK) can be used alongside commercially available SS nails to investigate the effect of initial IFS or stability on fracture healing with respect to different biological conditions of repair in rodents.

Nine-year-long complex humeral nonunion salvaged by distraction osteogenesis technique: a case report and review of the literature

Background

Humeral nonunion with significant bone loss or shortening is uncommon and poses a complex clinical problem. We present a case of humeral nonunion with a large segmental bone defect treated with the distraction osteogenesis technique and remedy the radial nerve palsy produced during distraction osteogenesis by forearm tendon transfers. The reconstruction of upper limb function was achieved with satisfactory results. This case provides a referenceable alternative method for repairing large segmental bone defects due to complex nonunion of the upper extremity, as well as a remedy in the unfortunate event of radial nerve palsy, providing a reference and lessons learned for the treatment of similar cases and the management of possible complications.

Case presentation

A 31-year-old male patient experienced 9 years of hypertrophic nonunion due to an unreliable internal fixation. The radiographs showed the absence of bone bridging between the two fragments, loosening of the screws, and extensive osteolysis around the internal screws. The patient was treated with distraction osteogenesis. At the end of the distraction period, the patient unfortunately developed right radial nerve paresis, which was salvaged by forearm tendon transplantation, and finally reconstructed hand function and achieved bone union of the humerus.

Conclusion

Distraction osteogenesis, although not a panacea for all humeral nonunions with significant segmental bone loss, does offer a viable salvage procedure in this unusual and often complex clinical problem. When irreversible radial nerve palsy occurs during distraction, forearm tendon transfers can have a good clinical effect.

Focal Dome Osteotomy for the Treatment of Diaphyseal Malunion of the Lower Extremity

The treatment of malunion of the lower extremity diaphysis is challenging. Diaphyseal osteotomies require extra care to promote bone healing. This may be enhanced through osteotomies, which do not produce bone gaps and allow for compression. The focal dome osteotomy allows for rotation around an axis to correct angular deformity. The production of a successful arcuate or focal dome osteotomy requires a suitable soft tissue host. The deformity analysis is not complex but essential to assess the feasibility of correction and is required for perfect execution of the osteotomy. This tutorial explains the technique for focal dome osteotomy to correct angular deformities of the lower extremities, specifically in the diaphysis. Surgical correction for malunion, infected malunion, and infected mal-nonunion case examples are discussed. With meticulous planning and surgical technique, the focal dome osteotomy is a viable option for correcting diaphyseal malunions with compression techniques that allow a stable construct for early weight-bearing.

Inhibition of Pathological Increased Matrix Metalloproteinase (MMP) Activity for Improvement of Bone Regeneration in Diabetes

Patients with diabetes suffer from poor fracture healing. Molecular reasons are not fully understood and our previous gene expression microarray analyses of regenerating bones from mice with type 2 diabetes (db⁻/db⁻) revealed accelerated activation of pathways concerning matrix metalloproteases (MMPs). Thus, we picked out the pathological MMP acceleration as a target for profound gene expression analyses and additional therapeutic intervention in the present study. In the first part, gene expression of ECM degrading proteinases and inhibitors was investigated three and seven days postoperatively. Mmp3, Mmp9, Mmp13 and gene expression of MMP inhibitor Timp2 was significantly higher in regenerating bone fractures of db⁻/db⁻ compared to wild type animals. Timp1 and metalloproteinase AdamTS4 showed no differences. In the second part, we locally applied a single dose (1 µL of 5 µM solution) of the broad-spectrum molecular MMP inhibitor Marimastat on tibial defects in db⁻/db⁻. We performed immunohistochemical and histological stainings seven days post operation. Impaired bone healing, collagen content, angiogenesis, and osteoclast invasion in db⁻/db⁻ were restored significantly by application of Marimastat compared to PBS controls (n = 7/group). Hence, local intervention of bone defects by the molecular MMP inhibitor Marimastat might be an alternative therapeutic intervention for bone healing in diabetes.

Nonunion of traumatic rib fractures: a suitable indication for surgery?

PURPOSE

Nonunion of traumatic rib fractures is a clinical/radiological diagnosis caused by an alteration of bone healing reparative process. Since it is a painful condition, nonunion has a significative impact on patient's morbidity and quality of life. The aim of this study was to evaluate the outcomes after surgical stabilization of ribs affected by nonunion after traumatic fractures.

METHODS

We conducted a retrospective cohort analysis of all patients who were treated with surgical stabilization of nonunion after traumatic rib fractures. We analyzed demographic data as well as clinical and patient-reported outcomes.

RESULTS

Nineteen patients were identified and included in this analysis. Median age was 49 years (range 25-69 years). Mean length of stay was 5.4 days. No in-hospital mortality was observed. After a median follow-up of 46.94 months (range 0-103), 16 (84.2%) patients were completely asymptomatic, while 3 (15.8%) were still suffering from pain after surgery.

CONCLUSIONS

Surgical stabilization in patients affected by rib nonunion can be safely performed with few complications, good clinical outcomes and satisfactory quality of life.

Fracture, nonunion and postoperative infection risk in the smoking orthopaedic patient: a systematic review and meta-analysis

This systematic review and meta-analysis aimed to analyse negative effects of smoking in orthopaedic and trauma patients.

A PubMed search was carried out for studies published until July 2020 regarding effects of smoking on fracture risk, nonunion, infection after orthopaedic surgery, and persisting nonunion after scaphoid nonunion surgery. Random effects models calculated for outcome parameters, and relative risks (RR) with 95% confidence intervals are provided. No adjustments for covariates were made. Heterogeneity was assessed with Higgins’ I2, publication bias with Harbord’s p (Hp), sensitivity analysis performed on funnel plots and quality of studies was analysed using the Newcastle-Ottawa Scale.

Of 3362 retrieved entries, 69 were included in the final analysis. Unadjusted RR for smokers to develop vertebral (six studies, seven entries; RR: 1.61; p = 0.008; I2 = 89.4%), hip (11 studies, 15 entries; RR: 1.28; p = 0.007; I2 = 84.1%), and other fractures (eight studies, 10 entries; RR: 1.75; p = 0.019; I2 = 89.3%) was significantly higher. Postoperative infection risk was generally higher for smokers (21 studies; RR: 2.20; p < 0.001; I2 = 58.9%), and remained upon subgroup analysis for elective spinal (two studies; RR: 4.38; p < 0.001; I2 = 0.0%) and fracture surgery (19 studies; RR: 2.10; p < 0.001; I2 = 58.5%). Nonunion risk after orthopaedic (eight studies; RR: 2.15; p < 0.001; I2 = 35.9%) and fracture surgery (11 studies; RR: 1.85; p < 0.001; I2 = 39.9%) was significantly higher for smokers, as was persisting nonunion risk after surgery for scaphoid nonunion (five studies; RR: 3.52; p < 0.001; I2 = 0.0%). Sensitivity analysis for each model reduced heterogeneity whilst maintaining significance (all I2 < 20.0%).

Smoking has a deleterious impact on fracture incidence, and (subsequent) development of nonunions and postoperative infections.

Cite this article: EFORT Open Rev 2021;6:1006-1019. DOI: 10.1302/2058-5241.6.210058

Posterior spinal instrumentation and decompression with or without cross-link?

Background

Posterior lumbar instrumentation requires sufficient primary stiffness to ensure bony fusion and to avoid pseudarthrosis, screw loosening, or implant failure. To enhance primary construct stiffness, transverse cross-link (CL) connectors attached to the vertical rods can be used. Their effect on the stability of a spinal instrumentation with simultaneous decompression is yet not clear. This study aimed to evaluate the impact of CL augmentation on single-level lumbar instrumentation stiffness after gradual decompression procedures.

Methods

Seventeen vertebral segments (6 L1/2, 6 L3/4, 5 L5/S1) of 12 fresh-frozen human cadavers were instrumented with a transpedicular screw–rod construct following the traditional pedicle screw trajectory. Range of motion (ROM) of the segments was sequentially recorded before and after four procedures: (A) instrumented before decompression, (B) instrumented after unilateral laminotomy, (C) instrumented after midline bilateral laminotomy, and (D) instrumented after unilateral facetectomy (with transforaminal lumbar interbody fusion [TLIF]). Each test was performed with and without CL augmentation. The motion between the cranial and caudal vertebrae was evaluated in all six major loading directions: flexion/extension (FE), lateral bending (LB), lateral shear (LS), anterior shear (AS), axial rotation (AR), and axial compression/distraction (AC).

Results

ROM was significantly reduced with CL augmentation in AR by Δ0.03–0.18° (7–12%) with a significantly higher ROM reduction after more extensive decompression. Furthermore, slight reductions in FE and LB were observed; these reached statistical significance for FE after facetectomy and TLIF insertion only (Δ0.15; 3%). The instrumentation levels did not reveal any subgroup differences.

Conclusion

CL augmentation reduces AR-ROM by 7–12% in single-level instrumentation of the lumbar spine, with the effect increasing along with the extensiveness of the decompression technique. In light of the discrete absolute changes, CL augmentation may be warranted for highly unstable vertebral segments rather than for standard single-level posterior spinal fusion and decompression.

The influence of smoking and alcohol on bone healing: Systematic review and meta-analysis of non-pathological fractures

BACKGROUND

We aimed to comprehensively evaluate the associations between (i) smoking, (ii) preoperative smoking cessation time, (iii) nicotine replacement therapy (NRT), (iv) vaping, and (v) alcohol consumption and non-pathological fracture healing in adult patients. We also assessed the impacts of preoperative smoking cessation time, NRT, and vaping on wound healing and wound complications after any sort of surgery.

METHODS

We searched the MEDLINE, Embase, Cochrane CENTRAL, CINAHL, and AMED electronic databases from their inceptions until August 9th, 2021. Primary outcomes included delayed union rate, nonunion rate, and time to union. A random effects model was used. (Protocol registration: PROSPERO-CRD42019131454).

FINDINGS

One hundred and twenty-two studies with 417,767 patients were eligible for the systematic review and 71 of the studies with 39,920 patients were eligible for the meta-analysis. After non-pathological fracture treatment, the nonunion rate was significantly greater in the smoker group than in the non-smoker group (odds ratio [OR], 2·50, 95% confidence interval [1·73-3·61]); additionally, there was no significant difference in the nonunion rate (OR, 0·97 [0·40-2·38]) between the alcohol drinker group and the non-drinker group. The rate of wound infection after surgery was significantly reduced in the smoking cessation group (≥four weeks before surgery) compared to the continuous smoker group (OR, 0·37 [0·16-0·89]).

INTERPRETATION

Smoking is associated with higher rates of nonunion and deep surgical site infection after non-pathological fracture treatment. Smoking cessation (≥four weeks before surgery) is associated with a decreased rate of postoperative wound infection.

FUNDING

The China Scholarship Council (no. 201809120013).

Effects of Collagen- and Arginine-Fortified Osteokine Supplementation on Fracture Healing

Introduction

Delayed union or nonunion is an important clinical challenge for orthopedic surgeons. In addition to the main treatment algorithms, the use of nutritional supplements is increasingly common. In this study, we investigated the effects of nutritional supplements fortified with arginine and collagen on fracture healing.

Materials and methods

Twenty-four rats with femur fractures were divided into experimental and control groups. Intramedullary fixation was performed in both groups. 20 ml/kg nutritional supplement was given to the experimental group. Radiological examination was performed at third and sixth weeks, and histopathological examination was performed at the sixth week.

Results

No statistically significant difference was found between the radiological scores of the groups at the third and sixth weeks. Nutritional supplement affected the histological properties of callus. Histological evidence of bone healing was observed by the sixth week in both groups but the score was higher in nutritional supplement group. A statistically significant difference was found between the histopathological scores of the groups at the sixth week.

Conclusion

Arginine- and type two collagen-augmented traditional nutritional supplements may help to achieve more successful results in fracture healing.

Single-Cell RNA Sequencing Reveals B Cells Are Important Regulators in Fracture Healing

The bone marrow microenvironment is composed primarily of immune and stromal cells that play important roles in fracture healing. Although immune cells have been identified in mouse bone marrow, variations in their numbers and type during the fracture healing process remain poorly defined. In this study, single-cell RNA sequencing was used to identify immune cells in fracture tissues, including neutrophils, monocytes, T cells, B cells, and plasma cells. The number of B cells decreased significantly in the early stage of fracture healing. Furthermore, B cells in mice fracture models decreased significantly during the epiphyseal phase and then gradually returned to normal during the epiphyseal transformation phase of fracture healing. The B-cell pattern was opposite to that of bone formation and resorption activities. Notably, B-cell-derived exosomes inhibited bone homeostasis in fracture healing. In humans, a decrease in the number of B cells during the epiphyseal phase stimulated fracture healing. Then, as the numbers of osteoblasts increased during the callus reconstruction stage, the number of B cells gradually recovered, which reduced additional bone regeneration. Thus, B cells are key regulators of fracture healing and inhibit excessive bone regeneration by producing multiple osteoblast inhibitors.

Evaluation of Inflammatory Response Due to Use of Controlled Release Drug Delivery System of Chitosan Hydrogel Loaded with Buprenorphine and Ketorolac in Rat with Experimental Proximal Tibial Epiphysis Defect

Aims:A controlled release drug delivery system loaded with buprenorphine and ketorolac was synthesized and used in the experimental model of bone defect and while evaluating the inflammatory response, the repair process in the defects was investigated.Materials and methods:To determine the effectiveness of the synthesized the mentioned systems, 5 groups were defined; the control group, the chitosan hydrogel receiving group (chitosan group), the ketorolac-loaded chitosan hydrogel group (ketorolac group), the buprenorphine-loaded chitosan hydrogel receiving group (buprenorphine group), and the chitosan hydrogel-loading group loaded with a combination of ketorolac and buprenorphine (ketorolac-buprenorphine group).Results:The results showed that the population of leukocytes (tWBC) and neutrophils on different days of the study in the control group compared to other groups had a significant increase (P < 0.05) while on day 7 of the study in the ketorolac group these parameters decreased significantly compared to other groups (P < 0.05). While examining the histological changes in the experimental defect created in the proximal tibia of rats at different times, some inflammatory indices such as total and differential leukocyte population, plasma concentrations of TNF-α and IL-6 were compared in different groups (P < 0.05). The various evaluated data showed that among the different groups, in the control and ketorolac-buprenorphine groups, there was the lowest and highest control of inflammatory response and bone repair, respectively.Conclusion:In the ketorolac group due to the impact of ketorolac on leukocyte populations the best bone healing can be expected among the different treatment groups.

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

OBJECTIVES

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

LEVEL OF EVIDENCE

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

NSAID Use and Effects on Pediatric Bone Healing: A Review of Current Literature

This systematic review evaluates and synthesizes the available peer-reviewed evidence regarding the impact of non-steroidal anti-inflammatory drugs (NSAIDs) on fracture healing in skeletally immature patients. Evidence supports the use of NSAIDs in this patient population for adequate pain control without increasing the risk of nonunion, particularly in long bone fractures and pseudoarthrosis after spine fusion. However, further clinical studies are needed to fill remaining gaps in knowledge, specifically with respect to the spectrum of available NSAIDs, dosage, and duration of use, in order to make broad evidence-based recommendations regarding the optimal use of NSAIDs during bone healing in skeletally immature patients.

Diagnostic prediction of ovine fracture healing outcomes via a novel multi-location direct electromagnetic coupling antenna

Background

Expedient prediction of adverse bone fracture healing (delayed- or non-union) is necessary to advise secondary treatments for improving healing outcome to minimize patient suffering. Radiographic imaging, the current standard diagnostic, remains largely ineffective at predicting nonunions during the early stages of fracture healing resulting in mean nonunion diagnosis times exceeding six months. Thus, there remains a clinical deficit necessitating improved diagnostic techniques. It was hypothesized that adverse fracture healing expresses impaired biological progression at the fracture site, thus resulting in reduced temporal progression of fracture site stiffness which may be quantified prior to the appearance of radiographic indicators of fracture healing (i.e., calcified tissue).

Methods

A novel multi-location direct electromagnetic coupling antenna was developed to diagnose relative changes in the stiffness of fractures treated by metallic orthopaedic hardware. The efficacy of this diagnostic was evaluated during fracture healing simulated by progressive destabilization of cadaveric ovine metatarsals treated by locking plate fixation (n=8). An ovine in vivo comparative fracture study (n=8) was then utilized to better characterize the performance of the developed diagnostic in a clinically translatable setting. In vivo measurements using the developed diagnostic were compared to weekly radiographic images and postmortem biomechanical, histological, and micro computed tomography analyses.

Results

For all cadaveric samples, the novel direct electromagnetic coupling antenna displayed significant differences at the fracture site (P<0.05) when measuring a fully fractured sample versus partially intact and fully intact fracture states. In subsequent in vivo fracture models, this technology detected significant differences (P<0.001) in fractures trending towards delayed healing during the first 30 days post-fracture.

Conclusions

This technology, relative to traditional X-ray imaging, exhibits potential to greatly expedite clinical diagnosis of fracture nonunion, thus warranting additional technological development.

Early weight bearing in acetabular and pelvic fractures

Background and aim of the work:

The incidence of pelvic and acetabular fractures is increasing during the years, counting 37 pelvic fractures per 100000 people annually. No weight bearing or toe touch weight bearing are usually chosen in the initial management to allow fracture and ligamentous healing and avoid fracture displacement and fixation failure. On the other hand, early weight bearing may stimulate fracture healing and allow prompt functional recovery, faster return to work and recreational activities and reduce complications linked to late rehabilitation. Aim of the study is to review the literature about weight bearing indications for pelvic and acetabular fractures to highlight clinical and biomechanical evidence supporting early weight bearing.

Methods:

Two independent reviewers independently extracted studies on early weight bearing of pelvic and acetabular fractures. All selected studies were screened independently based on title and abstract. Then the full text of any article that either judged potentially eligible was acquired and reviewed again. Any disagreement was resolved by discussing the full text manuscripts.

Results:

44 studies including reviews, meta-analysis, clinical and biomechanical studies were selected.

Conclusions:

Despite biomechanical data, few clinical evidences can be found to support early weight bearing in pelvic and especially acetabular fractures treatment. The promising results of some clinical experiences, however, should direct further studies to clearly define the indications and limits of early weight bearing in these injuries. Recognizing intrinsic lesion stability and bone and fixation technique quality, together with patient age and compliance, should be the mainstay for post-operative management choice. (www.actabiomedica.it)

Evaluation of the Relation Between Preload Values and Pull-Out Force of the Cortical Screw Used in Bone Fracture

This study aims to examine the relation between pull-out strength and preload values of the cortical screw used in bone fracture fixation. The research question is that "Does the pull-out strength of the cortical screw used in the bone fracture fixation change with the preload values of the screw change?". To perform this purpose, the finite element method was selected due to its ease to evaluate and calculate the stresses on the whole model. Models of a cortical screw, partial plate, and bone were created using the SolidWorks program. The material properties of the bone were selected orthotropic material type. The bone fixed on the distal and proximal ends. The pull-out forces were applied at the bottom of the plate. The screw that has been loaded ranges from 100 N-700 N as preload. The pull-out forces were determined 200-400-600 N as in the literature. The results show that the pull-out strength of the screw was changed when the preloaded values higher than 400 N. However, it was seen that the pull-out strength does not substantially change when the preload values were lower than 400 N. When the preload values were applied ≥500 N, the maximum von Mises stresses on the screw exceeded the critical strength of the screw material. In conclusion, the critical preload value was determined as 500 N for the optimum pull-out strength.

Effectiveness of parathyroid hormone (PTH) analogues on fracture healing: a meta-analysis

This meta-analysis evaluated the evidence for the use of parathyroid hormone (PTH) analogues to improve fracture healing. Eligible studies were prospective randomised controlled trials of adults with acute fractures treated with a PTH analogue. PTH improved functional outcomes but did not affect fracture healing rate or reduce pain.

PURPOSE

This meta-analysis evaluated the evidence of parathyroid hormone (PTH) analogues in fracture healing. The use of PTH analogues to prevent osteoporotic fractures is well investigated, and studies are emerging on extended indications. One such indication receiving increasing attention is the effect of PTH in fracture healing; however, the overall degree of efficacy remains inconclusive.

METHODS

A systematic electronic database search of MEDLINE, EMBASE and the Cochrane Library was conducted for relevant articles in August 2019 with no date restrictions. Randomised controlled trials of adults with acute fractures treated with a PTH analogue were included. PTH was compared with a comparator intervention, placebo or no treatment.

RESULTS

PTH analogue treatment improved functional outcomes in a range of fracture types but did not affect the fracture healing rate or reduce pain. Most trials included in this review were in elderly patients with osteoporosis. There was no evidence that PTH treatment caused harm or impeded fracture healing.

CONCLUSIONS

Meta-analysis of published data supports the use of PTH analogues to improve functional outcomes but not fracture healing rate or pain for different fracture types. The evidence for PTH analogue use in fracture healing is less clear in younger, non-osteoporotic patient populations. Trial design was heterogeneous and of limited quality, justifying further original trials.

MiR-144-5p, an exosomal miRNA from bone marrow-derived macrophage in type 2 diabetes, impairs bone fracture healing via targeting Smad1

BACKGROUND

Patients with diabetes have an increased risk of nonunion and delayed union of fractures. Macrophages have been shown as a key player in diabetic complications. However, it remains obscure how diabetic milieu affects macrophage-derived exosomes and its implications on osteogenic differentiation of BMSCs. In this study, we aim to define the impact of diabetic milieu on macrophage-derived exosomes, role of extracellular vesicles in intercellular communication with BMSCs, and subsequent effects on osteogenic differentiation and fracture repair.

RESULTS

The osteogenic potential and the ability of fracture repair of exosomes derived from diabetic bone marrow-derived macrophages (dBMDM-exos) were revealed to be lower, as compared with non-diabetic bone marrow-derived macrophages (nBMDM-exos) in vitro and in vivo. Interestingly, miR-144-5p levels were sharply elevated in dBMDM-exos and it could be transferred into BMSCs to regulate bone regeneration by targeting Smad1. In addition, the adverse effects of dBMDM-exos on the osteogenic potential and the ability of fracture repair were reversed through the suppression of miR-144-5p inhibition in vitro and vivo.

CONCLUSIONS

The results demonstrated an important role of exosomal miR-144-5p in bone regeneration, offering insight into developing new strategy for the improvement of fracture healing in patients with diabetes mellitus.

The impact of smoking on outcomes following anterior cervical fusion-nonfusion hybrid surgery: a retrospective single-center cohort study

BACKGROUND

There is mixed evidence for the impact of cigarette smoking on outcomes following anterior cervical surgery. It has been reported to have a negative impact on healing after multilevel anterior cervical discectomy and fusion, however, segmental mobility has been suggested to be superior in smokers who underwent one- or two-level cervical disc replacement. Hybrid surgery, including anterior cervical discectomy and fusion and cervical disc replacement, has emerged as an alternative procedure for multilevel cervical degenerative disc disease. This study aimed to examine the impact of smoking on intermediate-term outcomes following hybrid surgery.

METHODS

Radiographical and clinical outcomes of 153 patients who had undergone continuous two- or three-level hybrid surgery were followed-up to a minimum of 2-years post-operatively. The early fusion effect, 1-year fusion rate, the incidence of bone loss and heterotopic ossification, as well as the clinical outcomes were compared across three smoking status groups: (1) current smokers; (2) former smokers; (3) nonsmokers.

RESULTS

Clinical outcomes were comparable among the three groups. However, the current smoking group had a poorer early fusion effect and 1-year fusion rate (P < 0.001 and P < 0.035 respectively). Both gender and smoking status were considered as key factors for 1-year fusion rate. Upon multivariable analysis, male gender (OR = 6.664, 95% CI: 1.248-35.581, P = 0.026) and current smoking status (OR = 0.009, 95% CI: 0.020-0.411, P = 0.002) were significantly associated with 1-year fusion rate. A subgroup analysis demonstrated statistically significant differences in both early fusion process (P < 0.001) and the 1-year fusion rate (P = 0.006) across the three smoking status groups in female patients. Finally, non-smoking status appeared to be protective against bone loss (OR = 0.427, 95% CI: 0.192-0.947, P = 0.036), with these patients likely to have at least one grade lower bone loss than current smokers.

CONCLUSIONS

Smoking is associated with poor outcomes following hybrid surgery for multilevel cervical disc disease. Current smokers had the poorest fusion rate and most bone loss, but no statistically significant differences were seen in clinical outcomes across the three groups.

Clinical and Radiographic Predictors of Nonunion in Open Tibial Shaft Fractures

Open fracture is a risk factor for nonunion of diaphyseal tibia fractures. Compared with closed injuries, there is a relative lack of scientific knowledge regarding the healing of open tibia fractures. The objective of this study was to investigate which patient, injury, and surgeon-related factors predict nonunion in open tibial shaft fractures. A cohort of 98 patients with 104 extra-articular open tibial shaft fractures (OTA/AO 41A2-3, 42A-C, and 43A) were treated surgically between 2007 and 2018 at a single level 1 trauma center and were retrospectively reviewed. Patients underwent irrigation and debridement followed by definitive intramedullary nailing or plate fixation. Patient, injury, and perioperative prognostic factors were analyzed as predictors of nonunion based on anteroposterior and lateral radiographs. The nonunion rate was 27.9% (n=29). There were 12 occurrences of deep infection (11.5%). The median follow-up was 14 months. High-energy mechanism of injury (hazard ratio [HR], 5.76), Gustilo-Anderson class IIIA injury (HR, 3.66), postoperative cortical continuity of 0% to 25% (HR, 2.90), early postoperative complication (HR, 4.20), and deep infection (HR, 2.25) were significant predictors of nonunion on univariable analysis (P<.05). On multivariable assessment, only high-energy mechanism of injury, Gustilo-Anderson class IIIA injury, and early postoperative complication reached significance as predictors of nonunion. These data also indicate that lack of cortical continuity is a significant univariable radiographic predictor of nonunion. This is potentially modifiable, may guide surgeons in selecting patients for early bone grafting procedures, and should be assessed carefully in this high-risk population. [Orthopedics. 2021;44(3):142-147.].

Skeletal System Biology and Smoke Damage: From Basic Science to Medical Clinic

Cigarette smoking has a negative impact on the skeletal system, as it reduces bone mass and increases fracture risk through its direct or indirect effects on bone remodeling. Recent evidence demonstrates that smoking causes an imbalance in bone turnover, making bone vulnerable to osteoporosis and fragility fractures. Moreover, cigarette smoking is known to have deleterious effects on fracture healing, as a positive correlation between the daily number of cigarettes smoked and years of exposure has been shown, even though the underlying mechanisms are not fully understood. It is also well known that smoking causes several medical/surgical complications responsible for longer hospital stays and a consequent increase in the consumption of resources. Smoking cessation is, therefore, highly advisable to prevent the onset of bone metabolic disease. However, even with cessation, some of the consequences appear to continue for decades afterwards. Based on this evidence, the aim of our review was to evaluate the impact of smoking on the skeletal system, especially on bone fractures, and to identify the pathophysiological mechanisms responsible for the impairment of fracture healing. Since smoking is a major public health concern, understanding the association between cigarette smoking and the occurrence of bone disease is necessary in order to identify potential new targets for intervention.

Clinical use of mass spectrometry (imaging) for hard tissue analysis in abnormal fracture healing

Common traumas to the skeletal system are bone fractures and injury-related articular cartilage damage. The healing process can be impaired resulting in non-unions in 5-10% of the bone fractures and in post-traumatic osteoarthritis (PTOA) in up to 75% of the cases of cartilage damage. Despite the amount of research performed in the areas of fracture healing and cartilage repair as well as non-unions and PTOA, still, the outcome of a bone fracture or articular cartilage damage cannot be predicted. Here, we discuss known risk factors and key molecules involved in the repair process, together with the main challenges associated with the prediction of outcome of these injuries. Furthermore, we review and discuss the opportunities for mass spectrometry (MS) - an analytical tool capable of detecting a wide variety of molecules in tissues - to contribute to extending molecular understanding of impaired healing and the discovery of predictive biomarkers. Therefore, the current knowledge and challenges concerning MS imaging of bone and cartilage tissue as well as in vivo MS are discussed. Finally, we explore the possibilities of in situ, real-time MS for the prediction of outcome during surgery of bone fractures and injury-related articular cartilage damage.