Use of Teriparatide to improve fracture healing: What is the evidence?

Increased β2-adrenergic signaling promotes fracture healing through callus neovascularization in mice

Traumatic brain injury (TBI) leads to skeletal changes, including bone loss in the unfractured skeleton, and paradoxically accelerates healing of bone fractures; however, the mechanisms remain unclear. TBI is associated with a hyperadrenergic state characterized by increased norepinephrine release. Here, we identified the β2-adrenergic receptor (ADRB2) as a mediator of skeletal changes in response to increased norepinephrine. In a murine model of femoral osteotomy combined with cortical impact brain injury, TBI was associated with ADRB2-dependent enhanced fracture healing compared with osteotomy alone. In the unfractured 12-week-old mouse skeleton, ADRB2 was required for TBI-induced decrease in bone formation and increased bone resorption. Adult 30-week-old mice had higher bone concentrations of norepinephrine, and ADRB2 expression was associated with decreased bone volume in the unfractured skeleton and better fracture healing in the injured skeleton. Norepinephrine stimulated expression of vascular endothelial growth factor A and calcitonin gene-related peptide-α (αCGRP) in periosteal cells through ADRB2, promoting formation of osteogenic type-H vessels in the fracture callus. Both ADRB2 and αCGRP were required for the beneficial effect of TBI on bone repair. Adult mice deficient in ADRB2 without TBI developed fracture nonunion despite high bone formation in uninjured bone. Blocking ADRB2 with propranolol impaired fracture healing in mice, whereas the ADRB2 agonist formoterol promoted fracture healing by regulating callus neovascularization. A retrospective cohort analysis of 72 patients with long bone fractures indicated improved callus formation in 36 patients treated with intravenous norepinephrine. These findings suggest that ADRB2 is a potential therapeutic target for promoting bone healing.

Parathyroid hormone and trabectedin have differing effects on macrophages and stress fracture repair

Stress fractures occur as a result of repeated mechanical stress on bone and are commonly found in the load-bearing lower extremities. Macrophages are key players in the immune system and play an important role in bone remodeling and fracture healing. However, the role of macrophages in stress fractures has not been adequately addressed. We hypothesize that macrophage infiltration into a stress fracture callus site promotes bone healing. To test this, a unilateral stress fracture induction model was employed in which the murine ulna of four-month-old, C57BL/6 J male mice was repeatedly loaded with a pre-determined force until the bone was displaced a distance below the threshold for complete fracture. Mice were treated daily with parathyroid hormone (PTH, 50 μg/kg/day) starting two days before injury and continued until 24 h before euthanasia either four or six days after injury, or treated with trabectedin (0.15 mg/kg) on the day of stress fracture and euthanized three or seven days after injury. These treatments were used due to their established effects on macrophages. While macrophages have been implicated in the anabolic effects of PTH, trabectedin, an FDA approved chemotherapeutic, compromises macrophage function and reduces bone mass. At three- and four-days post injury, callus macrophage numbers were analyzed histologically. There was a significant increase in macrophages with PTH treatment compared to vehicle in the callus site. By one week of healing, treatments differentially affected the bony callus as analyzed by microcomputed tomography. PTH enhanced callus bone volume. Conversely, callus bone volume was decreased with trabectedin treatment. Interestingly, concurrent treatment with PTH and trabectedin rescued the reduction observed in the callus with trabectedin treatment alone. This study reports on the key involvement of macrophages during stress fracture healing. Given these observed outcomes on macrophage physiology and bone healing, these findings may be important for patients actively receiving either of these FDA-approved therapeutics.

Therapeutic Efficacy of Chinese Patent Medicine Containing Pyrite for Fractures: A Systematic Review and Meta-Analysis

Background and Objectives: Korean and traditional Chinese medicine state that pyrite is effective for fracture treatment, but supporting clinical data are limited. This systematic review aimed to investigate the therapeutic role of Chinese patent medicine containing pyrite (CPMP) in clinical treatment for fractures. Materials and Methods: Seven electronic databases were searched using the keywords "pyrite", "pyritum", and "zirantong" between inception and December 2022, yielding 29 published clinical studies. Randomized controlled trials that included CPMP were considered eligible regardless of the fracture type. Quality assessment and meta-analysis of the included RCTs were also performed. Results: Most studies showed high heterogeneity (I2 > 50%) and significant results (p < 0.05). Compared to the results of the control group, CPMP was more effective in terms of the primary outcome related to the efficacy rate, including the total effective rate, callus growth rate, bone union, and edema disappearance time (all p < 0.00001) and in terms of secondary outcomes related to pain reduction, namely pain intensity and pain disappearance time, than the control group (both p < 0.01). CPMP was more effective than the control group in terms of erythrocyte sedimentation rate (p < 0.01), hematocrit (p < 0.01), erythrocyte aggregation (p < 0.05), and plasma viscosity (p < 0.05). CPMP did not cause serious side effects, and the incidence of complications was significantly less than that in the control group. Conclusions: CPMP may be a safe and effective alternative treatment for fractures and may be beneficial in preventing postoperative complications, reducing pain, relieving symptoms, and accelerating healing.

Osteoporosis: Molecular Pathology, Diagnostics, and Therapeutics

Osteoporosis is a major public health concern affecting millions of people worldwide and resulting in significant economic costs. The condition is characterized by changes in bone homeostasis, which lead to reduced bone mass, impaired bone quality, and an increased risk of fractures. The pathophysiology of osteoporosis is complex and multifactorial, involving imbalances in hormones, cytokines, and growth factors. Understanding the cellular and molecular mechanisms underlying osteoporosis is essential for appropriate diagnosis and management of the condition. This paper provides a comprehensive review of the normal cellular and molecular mechanisms of bone homeostasis, followed by an in-depth discussion of the proposed pathophysiology of osteoporosis through the osteoimmunological, gut microbiome, and cellular senescence models. Furthermore, the diagnostic tools used to assess osteoporosis, including bone mineral density measurements, biochemical markers of bone turnover, and diagnostic imaging modalities, are also discussed. Finally, both the current pharmacological and non-pharmacological treatment algorithms and management options for osteoporosis, including an exploration of the management of osteoporotic fragility fractures, are highlighted. This review reveals the need for further research to fully elucidate the molecular mechanisms underlying the condition and to develop more effective therapeutic strategies.

GelMA-based bioactive hydrogel scaffolds with multiple bone defect repair functions: therapeutic strategies and recent advances

Currently, the clinical treatment of critical bone defects attributed to various causes remains a great challenge, and repairing these defects with synthetic bone substitutes is the most common strategy. In general, tissue engineering materials that mimic the structural, mechanical and biological properties of natural bone have been extensively applied to fill bone defects and promote in situ bone regeneration. Hydrogels with extracellular matrix (ECM)-like properties are common tissue engineering materials, among which methacrylate-based gelatin (GelMA) hydrogels are widely used because of their tunable mechanical properties, excellent photocrosslinking capability and good biocompatibility. Owing to their lack of osteogenic activity, however, GelMA hydrogels are combined with other types of materials with osteogenic activities to improve the osteogenic capability of the current composites. There are three main aspects to consider when enhancing the bone regenerative performance of composite materials: osteoconductivity, vascularization and osteoinduction. Bioceramics, bioglass, biomimetic scaffolds, inorganic ions, bionic periosteum, growth factors and two-dimensional (2D) nanomaterials have been applied in various combinations to achieve enhanced osteogenic and bone regeneration activities. Three-dimensional (3D)-bioprinted scaffolds are a popular research topic in bone tissue engineering (BTE), and printed and customized scaffolds are suitable for restoring large irregular bone defects due to their shape and structural tunability, enhanced mechanical properties, and good biocompatibility. Herein, the recent progress in research on GelMA-based composite hydrogel scaffolds as multifunctional platforms for restoring critical bone defects in plastic or orthopedic clinics is systematically reviewed and summarized. These strategies pave the way for the design of biomimetic bone substitutes for effective bone reconstruction with good biosafety. This review provides novel insights into the development and current trends of research on GelMA-based hydrogels as effective bone tissue engineering (BTE) scaffolds for correcting bone defects, and these contents are summarized and emphasized from various perspectives (osteoconductivity, vascularization, osteoinduction and 3D-bioprinting). In addition, advantages and deficiencies of GelMA-based bone substitutes used for bone regeneration are put forward, and corresponding improvement measures are presented prior to their clinical application in near future (created with BioRender.com).

Increased beta2-adrenergic signaling is a targetable stimulus essential for bone healing by promoting callus neovascularization

Traumatic brain injury (TBI) is associated with a hyperadrenergic state and paradoxically causes systemic bone loss while accelerating fracture healing. Here, we identify the beta2-adrenergic receptor (Adrb2) as a central mediator of these skeletal manifestations. While the negative effects of TBI on the unfractured skeleton can be explained by the established impact of Adrb2 signaling on bone formation, Adrb2 promotes neovascularization of the fracture callus under conditions of high sympathetic tone, including TBI and advanced age. Mechanistically, norepinephrine stimulates the expression of Vegfa and Cgrp primarily in periosteal cells via Adrb2, both of which synergistically promote the formation of osteogenic type-H vessels in the fracture callus. Accordingly, the beneficial effect of TBI on bone repair is abolished in mice lacking Adrb2 or Cgrp, and aged Adrb2-deficient mice without TBI develop fracture nonunions despite high bone formation in uninjured bone. Pharmacologically, the Adrb2 antagonist propranolol impairs, and the agonist formoterol promotes fracture healing in aged mice by regulating callus neovascularization. Clinically, intravenous beta-adrenergic sympathomimetics are associated with improved callus formation in trauma patients with long bone fractures. Thus, Adrb2 is a novel target for promoting bone healing, and widely used beta-blockers may cause fracture nonunion under conditions of increased sympathetic tone.

Abstract Figure

Republication of "Stress Fractures of the Foot and Ankle in Athletes"

Stress fractures of the foot and ankle are common injuries in athletes. Management differs considerably based on fracture location and predisposing factors. Repetitive loading of the foot and ankle in athletes should result in physiologic bone remodeling in accordance with Wolff's law. However, when there is not sufficient time for complete healing to occur before additional loads are incurred, this process can instead lead to stress fracture. Assessment of the athlete's training regimen and overall bone health is paramount to both the discovery and treatment of these injuries, although diagnosis is often delayed in the setting of normal-appearing initial radiographs. While most stress fractures of the foot or ankle can usually be treated nonoperatively with a period of activity modification, fractures in certain locations are considered "high risk" due to poor intrinsic healing and may warrant more proactive operative management.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Quantification of Anti-Osteoporotic Anabolic Peptide in Stealth Lipid Nanovesicles Through Validated RP-HPLC Method

BACKGROUND

Teriparatide is a recombinant fragment of human parathyroid hormone, a potent osteoanabolic agent used for osteoporosis.

OBJECTIVE

The present study endeavored to develop a simple, rapid, and reliable reverse phase-high performance liquid chromatography (RP-HPLC) method for the determination of teriparatide in pegylated lipid nanovesicles for rapid formulation development/optimization.

METHOD

A rapid RP-HPLC-based analytical method was developed for the quantification of teriparatide in pegylated lipid nanovesicles. The method was optimized on a Waters XBridge C18 (4.6 × 150 mm, 10 μm) column with a mobile phase consisting of 0.1% formic acid in water and acetonitrile both in a linear gradient program. In the method, a short run time of 9 min was achieved at a flow rate of 1.0 mL/min with an injection volume of 50 µL at a detection wavelength of 210 nm. The developed method was validated according to the ICH Q2 (R2) guideline. The method was applied for the quantification of teriparatide in prepared pegylated lipid nanovesicles. Teriparatide encapsulated pegylated lipid nanovesicles were prepared by the ethanol injection method. Further, these vesicles were characterized for % entrapment efficiency (%EE), particle size, zeta potential, and morphology by Cryo-SEM.

RESULTS

The teriparatide was eluting at 4.8 min in the run. Further, for the method validation, the linear relationship between concentration and response was established over the concentration range of 50-250 µg/mL with the R2 > 0.999. The method sensitivity was shown with LOD and LOQ with the value of 100 ng/mL and 500 ng/mL, respectively. The method was found to be accurate and precise with the recovery ranging in 100 ± 2% and RSD <2%, respectively. Minor deliberate changes proved the robustness of the developed method.

CONCLUSIONS

These results indicated that the developed and validated method is accurate, precise, rapid, reliable, and fit for the quantification of teriparatide in different formulations.

HIGHLIGHTS

The RP-HPLC method was developed and validated for the quantification of teriparatide from novel pegylated lipid nanovesicles.

Rib Fractures in Professional Baseball Pitchers: Mechanics, Epidemiology, and Management

Pitching is a complex kinetic chain activity requiring the transfer of energy from the lower body, through the core and trunk, and finally through the arm to generate explosive acceleration of the baseball. As a result, large forces are generated in the trunk musculature and rib attachments from the late cocking phase of pitching through deceleration. The repetitive cumulative load and high pitch velocities put professional pitchers at risk of rib stress fracture. Given the potential for a prolonged recovery course and high rate of recurrence, early recognition of rib bone stress injury is critical to optimize care. Identifying torso strength imbalances, suboptimal pitching biomechanics (such as late or inadequate pelvic rotation), as well as metabolic deficiencies that may adversely affect bone health are essential to expedite safe return to play and prevent future injury. In this review, we discuss risk factors, mechanism of injury, typical clinical presentation, diagnostic imaging findings, and propose treatment and prevention strategies for rib stress fractures in overhand pitchers.

Surgical and Pharmacological Management of Periprosthetic Atypical Femoral Fractures: A Narrative Literature Review

Introduction

An increasing number of patients is annually undergoing total hip arthroplasty (THA), and a significant proportion of these patients are elderly and consequently at a higher risk of complications because of age, osteoporosis, and medical comorbidities. Periprosthetic femoral fractures (PFFs) are one of the worst complications of THA associated with high rates of unfavorable prognosis. Besides, in the last decade, a new independent disease entity called “atypical femoral fracture” (AFF) has been identified and defined by the American Society for Bone and Mineral Research (ASBMR) task force. Some PFFs present clinical history and radiographic aspect consistent with an AFF, meeting the ASBMR criteria for the diagnosis of AFF except that PFFs by themselves are an exclusion criterion for AFF. However, there is an increasing number of published studies suggesting that periprosthetic atypical femoral fractures (PAFFs) exist and should not be excluded by definition.

Significance

Nowadays, although there is an increasing interest in PAFFs, there are still very few studies published on the topic and a lack of consensus regarding their treatment. This narrative literature review aims to introduce this new emerging topic to a wider readership describing the characteristics of PAFFs and the state-of-the-art in their management.

Conclusions

Many authors agree that PAFFs should be considered as a subgroup of PFFs that have atypical characteristics; they also show a significant correlation with prolonged bisphosphonate use. A correct diagnosis is paramount for proper treatment of the disease that requires both surgical and medical actions to be taken.

Treatment of osteoporotic fractures in alkaptonuria by teriparatide stimulates bone formation and decreases fracture rate - A report of two cases

Two cases of advanced alkaptonuria (AKU) with co-existing osteoporosis are described. Case 1 developed multiple non-vertebral fragility fractures, while Case 2 developed vertebral fragility fractures, both refractory to bisphosphonates. Difficulties in diagnosing osteoporosis in AKU complicated by extensive calcifying and ossifying spondylosis are discussed. Both patients continued to fracture despite nitisinone therapy for metabolic control of AKU, as well as bisphosphonate antiresorptive therapy for osteoporosis. Subsequently the patients were treated with teriparatide 20 μg subcutaneous injections daily for two years, leading to reduction in fractures soon after commencing therapy in both cases. Markers of bone remodelling P1NP and CTX were stimulated. No complications due hypercalcaemia or calcification were encountered in either case. We conclude that teriparatide is an effective adjunct in the treatment of AKU when bisphosphonates prove ineffective.

•

Two case of osteoporosis are described in patients with the ultra-rare genetic disorder, Alkaptonuria (AKU)

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Diagnosis of osteoporosis in AKU is complicated by extensive calcifying and ossifying spondylosis

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Treatment of AKU with Nitisinone and or antiresorptive did not improve bone health in these patients

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Teriparatide led to a reduction in fractures and is an effective adjunct in AKU when bisphosphonates prove ineffective

Revision osteosynthesis after primary treatment of atypical ulnar fractures associated with bisphosphonate usage - Nonunion after ordinary open reduction and internal fixation

BACKGROUND

We performed revision surgeries to treat nonunion of bisphosphonate-associated ulnar fractures that had originally been treated, after misdiagnosis, using the typical open reduction/internal fixation (ORIF).

METHODS

Of nine cases of ulnar nonunion initially treated at other institutions, we performed revision surgeries on four that met our inclusion/exclusion criteria. All previous implants were removed; the areas of nonunion were resected, and strut bone grafts were inserted and fixed with locking plates. Radiological assessments were performed monthly for 3 months after surgery and then every 3 months for 1 year.

RESULTS

All patients were female, with a mean age of 71.8 years. All patients had been taking bisphosphonate for a mean of 7.2 years. The primary fixation methods used at other institutions were intra-medullary nailing (n = 1) and placement of 3.5-mm locking plates (n = 3). In one patient (patient 1), the contralateral (right) ulna developed a new fracture at 1 month after revision surgery on the left ulna. Another patient (patient 3) exhibited an incomplete fracture in the contralateral (right) ulna. All four patients exhibited hip fractures (bilateral in three). All revisions resulted in final union at a mean of 4.8 months postoperatively.

CONCLUSION

Atypical ulnar fractures should be suspected in elderly women on long-term bisphosphonate treatment. Union will fail with standard ORIF for atypical ulnar fractures, because the fracture occurred due to compromised normal bone metabolism as reflected in the bone resorption, remodeling, and healing processes. Revision osteosynthesis using a locking plate with callus resection and strut/cancellous bone graft provided satisfactory results.

LEVEL OF EVIDENCE

Therapeutic level IV.

Current evidence on potential of adipose derived stem cells to enhance bone regeneration and future projection

Injuries to the postnatal skeleton are naturally repaired through successive steps involving specific cell types in a process collectively termed “bone regeneration”. Although complex, bone regeneration occurs through a series of well-orchestrated stages wherein endogenous bone stem cells play a central role. In most situations, bone regeneration is successful; however, there are instances when it fails and creates non-healing injuries or fracture nonunion requiring surgical or therapeutic interventions. Transplantation of adult or mesenchymal stem cells (MSCs) defined by the International Society for Cell and Gene Therapy (ISCT) as CD105+CD90+CD73+CD45-CD34-CD14orCD11b-CD79αorCD19-HLA-DR- is being investigated as an attractive therapy for bone regeneration throughout the world. MSCs isolated from adipose tissue, adipose-derived stem cells (ADSCs), are gaining increasing attention since this is the most abundant source of adult stem cells and the isolation process for ADSCs is straightforward. Currently, there is not a single Food and Drug Administration (FDA) approved ADSCs product for bone regeneration. Although the safety of ADSCs is established from their usage in numerous clinical trials, the bone-forming potential of ADSCs and MSCs, in general, is highly controversial. Growing evidence suggests that the ISCT defined phenotype may not represent bona fide osteoprogenitors. Transplantation of both ADSCs and the CD105^- sub-population of ADSCs has been reported to induce bone regeneration. Most notably, cells expressing other markers such as CD146, AlphaV, CD200, PDPN, CD164, CXCR4, and PDGFRα have been shown to represent osteogenic sub-population within ADSCs. Amongst other strategies to improve the bone-forming ability of ADSCs, modulation of VEGF, TGF-β1 and BMP signaling pathways of ADSCs has shown promising results. The U.S. FDA reveals that 73% of Investigational New Drug applications for stem cell-based products rely on CD105 expression as the “positive” marker for adult stem cells. A concerted effort involving the scientific community, clinicians, industries, and regulatory bodies to redefine ADSCs using powerful selection markers and strategies to modulate signaling pathways of ADSCs will speed up the therapeutic use of ADSCs for bone regeneration.

Atypical periprosthetic femoral fractures of the hip: A PRISMA compliant systematic review

INTRODUCTION

Long-term use of bisphosphonates (BPs) is associated with Atypical Femoral Fracture (AFF). Theoretically, periprosthetic femoral fractures (PFF) should be excluded from the diagnosis of AFF. However, recently several studies reported the occurrence of PPFs around a hip arthroplasty presenting features of an AFF. The present study describes the characteristics of Atypical Periprosthetic Femoral Fracture (APFF) and evaluates the effectiveness of their management through a PRISMA compliant systematic review of the published case reports and series.

MATERIALS AND METHODS

A literature search was performed using "periprosthetic fracture" and "atypical femoral fracture" as keywords. Patients demographics, drug use, clinical and imaging characteristics, stem fixation and classification, management strategies for APFF and patients' outcomes, were also collected.

RESULTS

The present review included and analysed 17 patients from 12 studies. All APFFs occurred in females with a mean age of 75.9 years of age (range 43-87). In 11 patients, APFFs occurred around an uncemented stem, and in 6 around a cemented stem. Ten fractures were incomplete, and 7 complete. Conservative management was effective in 4 of 10 patients with incomplete fracture, while all patients with complete fractures underwent open reduction and internal fixation. A fracture non-union was observed in 5 patients and further surgery was required.

DISCUSSIONS

APFFs share several clinical and imaging characteristics with AFF. An appropriate and early diagnosis may allow to improve the outcome of these fractures, the management of which should be based on the same principles of that of AFFs.

CONCLUSIONS

Considering the low quality of published articles and the heterogeneity of the treatment used, a clear recommendation of the most appropriate treatment cannot be formulated.

Refracture after Ilizarov fixation of infected ununited tibial fractures-an analysis of eight hundred and twelve cases

INTRODUCTION

Refracture of the tibia after union is a challenging problem for the patients and the surgeons. The purpose of the current study is to present our experience in conservative management of such patients with refracture of infected ununited tibia after successful treatment by Ilizarov external fixator and bone transport.

MATERIAL AND METHODS

We reviewed the files of 812 patients with infected ununited tibia who were treated by debridement, corticotomy, and bone transport using Ilizarov methods in our institute between 1997 and 2017. Inclusion criteria were patients with refracture after union and removal of the Ilizarov apparatus. Twenty-two patients with 23 refracture tibia were included in the study. All the 23 tibias were treated conservatively by above knee cast that was converted to Sarmiento below knee cast after early callus formation, except in the case of upper tibial fracture that continued in above knee cast till union. Afterwards, a protective splint was used for additional two months.

RESULTS

There were 19 males (86.4%) and three females (13.6%), the mean age of the patients was 38.39 years, the mean time of Ilizarov external fixator application was 10.86 months (range, 6-17), and the mean time of refracture after fixator removal was 2.33 months. Union was achieved in 19 tibias (82.6%), with a mean time of 7.2 months (range, 4-12). Complications included five cases of skin irritation that was treated by large windows in the cast and changing the casts more frequently, three cases developed DVT (deep venous thrombosis), and axial deviation occured in four tibias (17.3%).

CONCLUSION

Conservative treatment of refractured tibia after removal of Ilizarov external fixator following treatment of infected non-union tibia by above knee cast is effective in achieving union. However, complications as skin irritation, DVT (deep venous thrombosis), and axial deviation can be anticipated.

Role of supplemental teriparatide therapy in management of osteoporotic intertrochanteric femur fractures

BACKGROUND

Despite the surgical advances, obtaining the desired outcome in osteoporotic intertrochanteric femur fractures is still a tough row to hoe for the surgeons. Consequently, the interest of the researchers has shifted towards establishing a holistic approach for managing such injuries. Teriparatide, a recombinant form of human parathyroid hormone, is a novel drug that has been proved to hasten fracture healing and in both animals and humans. We attempted to evaluate the influence of Teriparatide therapy in surgically fixed osteoporotic intertrochanteric femur fractures and provide the groundwork for further research in this area.

METHODS

The results of osteoporotic patients who underwent only Proximal Femur Nailing [PFN] for intertrochanteric femur fractures were prospectively compared to the patients who received an additional Teriparatide therapy. We aimed to identify the effect of Teriparatide on the time to fracture union, bone mineral density [BMD], and other fracture related post-operative complications. The functional outcome was assessed using the Lower extremity functional scale [LEFS].

RESULTS

All patients were followed up for 6 months by which time all the fractures united. However, in the Teriparatide group, time to fracture union was shortened by about 2 weeks and improvement in BMD and functional outcome were significantly better. The rate of migration of the helical, varus collapse, and femoral shortening did not show any relevant difference.

CONCLUSION

Our preliminary attempt shows that early union coupled with better functional improvement and a substantial increase in BMD tips the balance in favour of the Teriparatide therapy in osteoporotic patients with intertrochanteric femur fractures. Well-designed clinical trials conducted in a similar vein are further required to support our claim.

The impact of sequential therapy from short-term teriparatide to denosumab compared with denosumab alone in patients with osteoporotic hip fracture: a 1-year follow-up study

Background

Sequential therapy from bone-forming medication to resorptive agents is reportedly effective for patients with severe osteoporosis. The objective of this study is to determine the impact of implementing short-term teriparatide (TPTD) intervention before denosumab (DMab) therapy compared with DMab therapy alone for 1 year after hip fracture.

Methods

We retrospectively reviewed the medical records and radiographs of patients who were treated due to osteoporotic hip fracture. TPTD was administered to 22 patients for an average of 12.1 weeks after which the intervention was switched to DMab therapy for 12 months (group 1). DMab alone was administered to 16 patients for 12 months (group 2). Bone mineral density (BMD) was evaluated before and after treatment at the 1-year follow-up. The improvement of BMD in hip and spine was compared with the levels of bone turnover marker.

Results

The difference in femoral neck BMD was 0.005 ± 0.04 in group 1 and − 0.014 ± 0.10 in group 2 (p = 0.442). The difference of spine BMD was 0.043 ± 0.05 in group 1 and 0.052 ± 0.06 in group 2 (p = 0.640). BMD of the spine improved significantly in groups 1 and 2 (p < 0.001, p = 0.002). There was no statistical difference in C-terminal telopeptide and osteocalcin level.

Conclusion

Short-term TPTD administration followed by DMab alone was effective only in improving spine BMD. Short-term treatment with TPTD caused mild improvement in femur neck BMD compared with DMab alone. However, further research with a longer duration of TPTD treatment is warranted, as our findings lack statistical significance.

Does Teriparatide Improve Fracture Union?: A Systematic Review

We conducted an updated review of the evidence of teriparatide (TPTD) for fracture healing for the following questions. (1) Does it decrease fracture healing time?; (2) Can it be an alternative treatment for nonunion?; (3) Does it aid the union of atypical femoral fracture (AFF)? We searched PubMed, EMBASE, and Cochrane Library including “Fracture” AND “nonunion” AND “Teriparatide”. In total, 57 publications met our inclusion criteria were summarized. This systemic review of the available literature revealed that TPTD works positively with regard to enhancing fracture healing time and union of AFF. There are also many case studies on the use of TPTD could be a potential new safe treatment for nonunion with no side effects. However, level 1 studies on the evidence of TPTD are still lacking so far. Over the last decade, a growing body of evidence has accumulated suggesting that TPTD can be an adjunct to enhance fracture healing or a therapeutic option to treat nonunion, but greater evidences from large volume prospective trials are needed.

Nanocomposites drug delivery systems for the healing of bone fractures

The skeletal system is fundamental for the structure and support of the body consisting of bones, cartilage, and connective tissues. Poor fracture healing is a chief clinical problem leading to disability, extended hospital stays and huge financial liability. Even though most fractures are cured using standard clinical methods, about 10% of fractures are delayed or non-union. Despite decades of progress, the bone-targeted delivery system is still restricted due to the distinctive anatomical bone features. Recently, various novel nanocomposite systems have been designed for the cell-specific targeting of bone, enhancing drug solubility, improving drug stability and inhibiting drug degradation so that it can reach its target site without being removed in the systemic circulation. Such targeting systems could consist of biological compounds i.e. bone marrow stem cells (BMSc), growth factors, RNAi, parathyroid hormone or synthetic compounds, i.e. bisphosphonates (BPs) and calcium phosphate cement. Hydrogels and nanoparticles are also being employed for fracture healing. In this review, we discussed the normal mechanism of bone healing and all the possible drug delivery systems being employed for the healing of the bone fracture.

Enhancement of the effects of intermittent parathyroid hormone (1-34) by bone morphogenetic protein in a rat femoral open fracture model

Background

Nonunion in cases of open fracture is common. Both bone morphogenetic protein 2 (BMP-2) and parathyroid hormone (PTH) have been used to enhance bone healing. We investigated the combination of BMP-2 and PTH and examined the effects on a rat model of open femoral fractures.

Methods

Group I (n = 11) was implanted with control carrier. Group II (n = 12) was implanted with carrier containing 1 μg of recombinant human BMP-2 (rhBMP-2). Group III (n = 12) was implanted with carrier alone, followed by injections of PTH 1-34. Group IV (n = 11) was implanted with carrier containing 1 μg of rhBMP-2, followed by injections of PTH 1-34. Group V (n = 11) was implanted with carrier containing 10 μg of rhBMP-2. Group VI (n = 11) was implanted with carrier containing 10 μg of rhBMP-2, followed by injections of PTH 1-34. Rats were euthanized after 8 weeks, and their fractured femurs were explanted and assessed by manual palpation, radiographs, micro-computerized tomography, and histological analysis.

Results

Manual palpation tests showed that the fusion rates of groups III (66.7%), IV (63.6%), V (81.8%), and VI (81.8%) were considerably higher than those of group I. Groups V and VI had higher radiographic scores compared to group I. Micro-CT analysis revealed enhanced bone marrow density expressed as bone volume/tissue volume in groups V (61.88 ± 3.16%) and VI (71.14 ± 3.89%) versus group I (58.26 ± 1.86%). A histological analysis indicated that group VI had enhanced remodeling.

Conclusion

The combination of abundant rhBMP-2 and PTH enhanced bone healing and remodeling of newly formed bone in a rat femoral open fracture model.

Teriparatide as nonoperative treatment for femoral shaft atrophic nonunion: A case report

BACKGROUND

Femoral shaft fractures are a common type of fracture among adults and have high union rates. However, clinical decisions are difficult to make because of the different types of nonunions. Atrophic nonunion usually requires revision surgery combined with bone grafting. Furthermore, no study of teriparatide administration for femoral atrophic nonunion have been previously reported.

CASE SUMMARY

A 60-year-old woman had a right femoral shaft fracture due to a traffic accident, and she immediately underwent closed reduction and internal fixation surgery with an intramedullary nailing. However, after 6 mo of rehabilitation, the fracture site showed no signs of healing, and her condition was diagnosed as atrophic nonunion. Subsequently, teriparatide was administered for 6 mo. Complete union was observed at the fracture site 6 mo after teriparatide discontinued.

CONCLUSION

The use of teriparatide can be a promising treatment to improve the healing of nonunion fractures.

Dysfunctional stem and progenitor cells impair fracture healing with age

Successful fracture healing requires the simultaneous regeneration of both the bone and vasculature; mesenchymal stem cells (MSCs) are directed to replace the bone tissue, while endothelial progenitor cells (EPCs) form the new vasculature that supplies blood to the fracture site. In the elderly, the healing process is slowed, partly due to decreased regenerative function of these stem and progenitor cells. MSCs from older individuals are impaired with regard to cell number, proliferative capacity, ability to migrate, and osteochondrogenic differentiation potential. The proliferation, migration and function of EPCs are also compromised with advanced age. Although the reasons for cellular dysfunction with age are complex and multidimensional, reduced expression of growth factors, accumulation of oxidative damage from reactive oxygen species, and altered signaling of the Sirtuin-1 pathway are contributing factors to aging at the cellular level of both MSCs and EPCs. Because of these geriatric-specific issues, effective treatment for fracture repair may require new therapeutic techniques to restore cellular function. Some suggested directions for potential treatments include cellular therapies, pharmacological agents, treatments targeting age-related molecular mechanisms, and physical therapeutics. Advanced age is the primary risk factor for a fracture, due to the low bone mass and inferior bone quality associated with aging; a better understanding of the dysfunctional behavior of the aging cell will provide a foundation for new treatments to decrease healing time and reduce the development of complications during the extended recovery from fracture healing in the elderly.

Successful treatment of pathologic femoral shaft fracture associated with large arteriovenous malformations using a 3-dimensional external fixator and teriparatide: a case report

Background

Arteriovenous malformations (AVMs) are rare congenital vascular lesions associated with early quiescence, late expansion, and, ultimately, infiltration and destruction of local soft tissue and bone. The extremities are a common location. Incidence of bony involvement by AVM has been reported as high as 31%. However, there are few reports on management of pathologic fracture associated with AVM. Teriparatide is a recombinant parathyroid hormone (PTH) analogue consisting of the 1–34 fragment of PTH. Recently, some reports have shown the ability of teriparatide to improve fracture healing. Here, we present a case of pathologic femoral shaft fracture associated with large AVMs that was treated successfully by external fixation and teriparatide.

Case presentation

A 68-year-old Japanese woman, previously diagnosed as having large AVMs, sustained a right femoral shaft fracture due to a fall. At the time of admission, she presented with massive swelling and venous varicosities of the right thigh. Plain radiography of the right thigh revealed femoral shaft fracture with bony erosion and calcification of soft tissue. We planned closed reduction and intramedullary nailing with a unilateral external fixator following embolization of the feeding artery. However, closed reduction using the fracture table was difficult. When we attempted open reduction, massive bleeding (1000 mL) after incision of subcutaneous tissue occurred. Finally, we carefully applied a Taylor Spatial Frame. Fracture displacement was corrected successfully and bony union was obtained with administration of teriparatide 15 months after the initial surgery. The patient is able to walk using 1 cane.

Conclusion

We present the first report of pathologic fracture associated with large AVMs that achieved bony union using a 3-dimensional external fixator and teriparatide.

Bone-Fracture-Targeted Dasatinib-Oligoaspartic Acid Conjugate Potently Accelerates Fracture Repair

Approximately 6.3 million bone fractures occur annually in the United States, resulting in considerable morbidity, deterioration in quality of life, loss of productivity and wages, and sometimes death (e.g., hip fractures). Although anabolic and antiresorptive agents have been introduced for treatment of osteoporosis, no systemically administered drug has been developed to accelerate the fracture-healing process. To address this need, we have undertaken to target a bone anabolic agent selectively to fracture surfaces in order to concentrate the drug's healing power directly on the fracture site. We report here that conjugation of dasatinib to a bone fracture-homing oligopeptide via a releasable linker reduces fractured femur healing times in mice by ∼60% without causing overt off-target toxicity or remodeling of nontraumatized bones. Thus, achievement of healthy bone density, normal bone volume, and healthy bone mechanical properties at the fracture site is realized after only 3-4 weeks in dasatinib-targeted mice, but it requires ∼8 weeks in PBS-treated controls. We conclude that targeting of dasatinib to bone fracture surfaces can significantly accelerate the healing process at dasatinib concentrations that are known to be safe in oncological applications.

Stress Fractures of the Foot and Ankle in Athletes

Stress fractures of the foot and ankle are common injuries in athletes. Management differs considerably based on fracture location and predisposing factors. Repetitive loading of the foot and ankle in athletes should result in physiologic bone remodeling in accordance with Wolff’s law. However, when there is not sufficient time for complete healing to occur before additional loads are incurred, this process can instead lead to stress fracture. Assessment of the athlete’s training regimen and overall bone health is paramount to both the discovery and treatment of these injuries, although diagnosis is often delayed in the setting of normal-appearing initial radiographs. While most stress fractures of the foot or ankle can usually be treated nonoperatively with a period of activity modification, fractures in certain locations are considered “high risk” due to poor intrinsic healing and may warrant more proactive operative management.

Non-union after plate fixation

Approximately a third of patients presenting with long-bone non-union have undergone plate fixation as their primary procedure. In the assessment of a potential fracture non-union it is critical to understand the plating technique that the surgeon was intending to achieve at the primary procedure, i.e. whether it was direct or indirect fracture repair. The distinction between delayed union and non-union is a diagnostic dilemma especially in plated fractures, healing by primary bone repair. The distinction is important as nonunions are not necessarily part of the same spectrum as delayed unions. The etiology of a fracture non-union is usually multifactorial and the factors can be broadly categorized into mechanical factors, biological (local and systemic) factors, and infection. Infection is present in ~40% of fracture non-unions, often after open fractures or impaired wound healing, but in 5% of all non-unions infection is present without any clinical or serological suspicion. Methods to improve the sensitivity of investigation in the search of infection include the use of; sonication of implants, direct inoculation of theatre specimens into broth, and histological examination of non-union site tissue. Awareness should be given to the potential anti-osteogenic effect of bisphosphonates (in primary fracture repair) and certain classes of antibiotics. Early cases of delayed/non-union with sufficient mechanical stability and biologically active bone can be managed by stimulation of fracture healing. Late presenting non-union typically requires revision of the fixation construct and stimulation of the callus to induce fracture union.

MicroRNA-185 inhibits the growth and proliferation of osteoblasts in fracture healing by targeting PTH gene through down-regulating Wnt/β -catenin axis: In an animal experiment

Fracture healing is a repair process of a mechanical discontinuity loss of force transmission, and pathological mobility of bone. Increasing evidence suggests that microRNA (miRNA) could regulate chondrocyte, osteoblast, and osteoclast differentiation and function, indicating miRNA as key regulators of bone formation, resorption, remodeling, and repair. Hence, during this study, we established a right femur fracture mouse model to explore the effect microRNA-185 (miR-185) has on osteoblasts in mice during fracture healing and its underlying mechanism. After successfully model establishment, osteoblasts were extracted and treated with a series of mimics or inhibitors of miR-185, or siRNA against PTH. Quantitative reverse transcription polymerase chain reaction (qRT-PCR) and western blot analysis were performed to determine the levels of miR-185, PTH, β-catenin and Wnt5b. Cell viability, cycle distribution and apoptosis were detected by means of MTT and flow cytometry assays. Dual luciferase reporter gene assay verified that PTH is a target gene of miR-185. Osteoblasts transfected with miR-185 mimics or siRNA against PTH presented with decreased levels of PTH, β-catenin and Wnt5b which indicated that miR-185 blocks the Wnt/β -catenin axis by inhibiting PTH. Moreover, miR-185 inhibitors promoted the osteoblast viability and reduced apoptosis with more cells arrested at the G1 stage. MiR-185 mimics were observed to have inhibitory effects on osteoblasts as opposed to those induced by miR-185 inhibitors. Above key results indicated that suppression of miR-185 targeting PTH could promote osteoblast growth and proliferation in mice during fracture healing through activating Wnt/β -catenin axis.

The Effects of Systemic Therapy of PEGylated NEL-Like Protein 1 (NELL-1) on Fracture Healing in Mice

Fractures are common, with an incidence of 13.7 per 1000 adults annually. Systemic agents have been widely used for enhancing bone regeneration; however, the efficacy of these therapeutics for the management and prevention of fracture remains unclear. NEL-like protein 1 (NELL-1) is a potent pro-osteogenic cytokine that has been modified with polyethylene glycol (PEG)ylation [PEGylated NELL-1 (NELL-PEG)] to enhance its pharmacokinetics for systemic therapy. Our aim was to investigate the effects of systemic administration of NELL-PEG on fracture healing in mice and on overall bone properties in uninjured bones. Ten-week-old CD-1 mice were subjected to an open osteotomy of bilateral radii and treated with weekly injections of NELL-PEG or PEG phosphate-buffered saline as control. Systemic injection of NELL-PEG resulted in improved bone mineral density of the fracture site and accelerated callus union. After 4 weeks of treatment, mice treated with NELL-PEG exhibited substantially enhanced callus volume, callus mineralization, and biomechanical properties. NELL-PEG injection significantly augmented bone regeneration, as confirmed by high expression of bone turnover rate, bone formation rate, and mineral apposition rate. Consistently, the immunohistochemistry results also confirmed a high bone remodeling activity in the NELL-PEG-treated group. Our findings suggest that weekly injection of NELL-PEG may have the clinical potential to accelerate fracture union and enhance overall bone properties, which may help prevent subsequent fractures.

Bone grafts and biomaterials substitutes for bone defect repair: A review

Bone grafts have been predominated used to treat bone defects, delayed union or non-union, and spinal fusion in orthopaedic clinically for a period of time, despite the emergency of synthetic bone graft substitutes. Nevertheless, the integration of allogeneic grafts and synthetic substitutes with host bone was found jeopardized in long-term follow-up studies. Hence, the enhancement of osteointegration of these grafts and substitutes with host bone is considerably important. To address this problem, addition of various growth factors, such as bone morphogenetic proteins (BMPs), parathyroid hormone (PTH) and platelet rich plasma (PRP), into structural allografts and synthetic substitutes have been considered. Although clinical applications of these factors have exhibited good bone formation, their further application was limited due to high cost and potential adverse side effects. Alternatively, bioinorganic ions such as magnesium, strontium and zinc are considered as alternative of osteogenic biological factors. Hence, this paper aims to review the currently available bone grafts and bone substitutes as well as the biological and bio-inorganic factors for the treatments of bone defect.

Treatment of Atypical Ulnar Fractures Associated with Long-Term Bisphosphonate Therapy for Osteoporosis: Autogenous Bone Graft with Internal Fixation

Long-term bisphosphonate use has been suggested to result in decreased bone remodelling and an increased risk of atypical fractures. Fractures of this nature commonly occur in the femur, and relatively few reports exist to show that they occur in other bones. Among eight previous reports of atypical ulnar fractures associated with bisphosphonate use, one report described nonunion in a patient who was treated with cast immobilization and another described ulna nonunion in one of three patients, all of whom were treated surgically with a locking plate. The remaining two surgical patients achieved bone union uneventfully following resection of the osteosclerotic lesion and iliac bone grafting before rigid fixation. We hypothesized that the discontinuation of bisphosphonate therapy, the use of teriparatide treatment, and low-intensity pulsed ultrasound (LIPUS) might have been associated with fracture healing.

Alpinumisoflavone inhibits osteoclast differentiation and exerts anti-osteoporotic effect in ovariectomized mice

Alpinumisoflavone (AIF), a naturally occurring flavonoid compound exacted from Derris eriocarpa, has been found to have a number of pharmacological activities. However, its role in bone disorder has not been investigated. The aim of this study is to evaluate the osteoprotective effect of AIF on ovariectomy-induced bone loss in mice model and related underlying mechanisms. Our study provides experimental evidence that AIF could regulate the remodeling process of bone and exert osteoprotective effect against ovariectomy-induced bone loss. Moreover, our results show that AIF suppresses osteoclast differentiation by attenuating RANKL-induced activation of p38, ERK and JNK pathways and consequently represses the expression of c-Fos and NFATc1.

Effect of parathyroid hormone on healing in osteoporotic fractures via a phospholipase C-independent pathway

Objective

This study was performed to investigate the effect of parathyroid hormone (PTH) on healing in osteoporotic fractures via a phospholipase C (PLC)-independent pathway and explore the mechanism of PTH-mediated bone formation.

Methods

Ninety-six 12-week-old C57BL/6J female mice underwent bilateral ovariectomy. One month later, the lower third of the femur was fractured and the mice were treated using saline, PTH(1-28), PTH(1-34), zoledronic acid (ZA), PTH(1-28)+ZA, and PTH(1-34)+ZA. The mice were killed at weeks 2 and 4 in each group. Biomechanical testing and micro-computed tomography were performed.

Results

The formation and strength of the callus increased in all but the saline group. The mice treated with PTH(1-34) showed a significantly higher ultimate bending force, bending rigidity, bone mineral density, percent bone volume, and trabecular thickness than those treated with PTH(1-28). The PTH(1-34)+ZA group demonstrated the greatest improvements in the ultimate bending force, bending rigidity, bone mineral density, and relative bone volume.

Conclusions

PTH can promote fracture healing and callus hardness in ovariectomized mice by increasing callus formation and reconstructing trabecular bone via a PLC-independent pathway. PTH combined with ZA has a cumulative effect on the healing of fractures in ovariectomized mice.

Management of atypical femoral fracture: a scoping review and comprehensive algorithm

BACKGROUND

Atypical femoral fractures (AFF) are a rare type of femoral stress fracture recently described, potentially associated with prolonged bisphosphonate therapy. Evidence-based recommendations regarding diagnosis and management of these fractures are scarce. The purpose of this study is to propose an algorithm for the diagnosis and management of AFF.

METHODS

We performed a PubMed search of the last ten years using the keywords "atypical femoral fractures" and identified further articles through an evaluation of the publications cited in these articles. Relevant studies were included by agreement between researchers, depending on their specialization. Pertinent points of debate were discussed based on the available literature, allowing for consensus regarding the proposed management algorithm.

RESULTS

Using a systematic approach we performed a scoping review that included a total of 137 articles.

CONCLUSIONS

A practical guide for diagnosis and management of AFF based on the current concepts is proposed. In spite of the impressive large volume of published literature available since AFF were initially identified, the level of evidence is mostly poor, in particular regarding treatment choice. Therefore, further studies are required.

Bone pain: current and future treatments

Skeletal conditions are common causes of chronic pain and there is an unmet medical need for improved treatment options. Bone pain is currently managed with disease modifying agents and/or analgesics depending on the condition. Disease modifying agents affect the underlying pathophysiology of the disease and reduce as a secondary effect bone pain. Antiresorptive and anabolic agents, such as bisphosphonates and intermittent parathyroid hormone (1-34), respectively, have proven effective as pain relieving agents. Cathepsin K inhibitors and anti-sclerostin antibodies hold, due to their disease modifying effects, promise of a pain relieving effect. NSAIDs and opioids are widely employed in the treatment of bone pain. However, recent preclinical findings demonstrating a unique neuronal innervation of bone tissue and sprouting of sensory nerve fibers open for new treatment possibilities.