Principles of Nonunion Management: State of the Art

A systematic scoping review of the latest data on orthobiologics in the surgical treatment of non-union

INTRODUCTION

Recent studies have shown a growing concern regarding the cost-effectiveness and the lack of supporting data for the biologic agents that are being increasingly used in the orthopedic field. Our aim was to conduct a systematic scoping review of recent publications (last five years) on the use of orthobiologics to treat fracture non-union and summarize the latest available data.

PATIENTS AND METHODS

The inclusion criteria for this review were articles published in English, from 2016 to 2022, and focusing on the use of orthobiologics for the surgical treatment of non-union. Searches were conducted in March 2023 using Pubmed/MEDLINE and Embase. Studies on spinal fusion or gene therapy were excluded. Reviews, case reports with five cases or less, conference proceedings, preliminary reports, pediatric or non-human studies were excluded as well.

RESULTS

The search found 1807 articles, 15 were eligible after PRISMA checklist and exclusions. The evidence was heterogenous and there was only one level II RCT. Recent data suggests that bone morphogenic protein (BMP-2) products could be effective for septic and aseptic tibial non-unions. However, the evidence was not conclusive regarding BMP-7, plasma rich platelets (PRP), stem cells or demineralized bone matrix (DBM).

DISCUSSION

Every non-union case is different in terms of bone defect, biology, mechanical stability, surgical technique and host factors, which contributes to the conflicting reports on the efficacy of orthobiologics in the literature. We might never see a level 1, high powered and robust study defining the efficacy, safety profile and cost-effectiveness of such products.

LEVEL OF EVIDENCE

IV.

Proximal tibial replacement with megaprosthesis in the setting of proximal tibial nonunion: A case report

Background

Fracture nonunion is a major concern among an orthopaedic patient population, especially in those who have sustained traumatic fractures involving the tibia. Strong risk factors for nonunion include age, smoking history, and a poor diet. The incidence of nonunion also increases with each additional failed surgical intervention.

Methods

Our retrospective case study involved 56-year-old woman with a history of chronic low back pain, osteopenia, malnutrition, smoking, marijuana use, and alcohol use, who presented with a proximal tibia fracture after a fall, initial treatment included temporization with multiplanar external fixation and subsequent internal fixation. Five weeks later, she presented with atrophic nonunion. She subsequently underwent multiple unsuccessful surgeries to address her nonunion, including open repair with bone grafting and multiplanar external fixation for bone transport. Ultimately, the nonunion was addressed by proximal tibia replacement with megaprosthesis with excellent clinical results.

Results and conclusion

Replacement of a proximal tibia with megaprosthesis is a viable option for limb salvage, especially when all alternative treatments have been unsuccessful.

Assessment, Diagnosis and Management Strategies for Forearm Shaft Non-union: A Contemporary Perspective

Forearm non-union poses a challenge in orthopaedic surgery due to its intricate anatomy and functional significance. This review provides a comprehensive overview of the assessment, diagnosis and management of forearm non-union. Initial evaluation involves a meticulous history, physical examination and imaging studies to identify factors contributing to non-union, including infection. Surgical approaches are discussed, with emphasis on restoring biomechanical stability and promoting bone healing. Treatment options range from autografts to allografts, with considerations for vascularised bone transfers in complex cases. Decision-making strategies are outlined, considering patient-specific factors and individualised treatment plans. Special considerations for specific types of forearm non-unions are addressed, along with postoperative care protocols to optimise healing and functional outcomes. Overall, this review aims to provide clinicians with a comprehensive understanding of forearm non-union management based on current evidence and clinical practice. Level of Evidence: Level V (Therapeutic).

[Non-unions of the upper extremities]

The diagnosis and treatment of non-unions still represents an interdisciplinary challenge. Therefore, prevention, early detection and specific treatment are of great importance. Non-unions of the upper extremities, although less common than that of the lower extremities, requires special attention for successful treatment due to the central role of the shoulder girdle and arm in day to day activities. Successful treatment of non-unions requires a comprehensive evaluation of the patient's medical history, a thorough clinical examination and in particular radiological imaging. In order to effectively treat the pseudarthrosis it is crucial to distinguish between pseudarthroses that are suspected to be due to infections and those that are not. This article presents a treatment algorithm for managing both pseudarthrosis due to infection and pseudarthrosis without infection in the upper extremities.

Bone marrow aspirate and bone marrow aspirate concentrate: Does the literature support use in long-bone nonunion and provide new insights into mechanism of action?

PURPOSE

To assess the use of bone marrow aspirate (BM) and bone marrow aspirate concentrate (BMAC) in the treatment of long-bone nonunion and to understand mechanism of action.

METHODS

A systematic review of PubMed and EBSCOHost was completed to identify studies that investigated the use of BM or BMAC for the diagnosis of delayed union and/or nonunion of long-bone fractures. Studies of isolated bone marrow-mesenchymal stem cells (BM-MSCs) and use in non-long-bone fractures were excluded. Statistical analysis was confounded by heterogeneous fracture fixation methods, treatment history, and scaffold use.

RESULTS

Our initial search yielded 430 publications, which was screened down to 25 studies. Successful treatment in aseptic nonunion was reported at 79-100% (BM) and 50-100% (BMAC). Septic nonunion rates were slightly better at 73-100% (BM) and 83.3-100% (BMAC). 18/24 studies report union rates > 80%. One study reports successful treatment of septic nonunion with BMAC and no antibiotics. A separate study reported a significant reduction in autograft reinfection rate when combined with BMAC (P = 0.009). Major adverse events include two deep infections at injection site and one case of heterotopic ossification. Most studies note transient mild donor site discomfort and potential injection site discomfort attributed to needle size.

CONCLUSION

The current literature pertaining to use of BM/BMAC for nonunion is extremely heterogeneous in terms of patient population and concomitant treatment modalities. While results are promising for use of BM/BMAC with other gold standard treatment methodologies, the literature requires additional Level I data to clarify the impact of role BM/BMAC in treating nonunion when used alone and in combination with other modalities.

LEVEL OF EVIDENCE

Level III.

Prognostic factors of extracorporeal shockwave therapy in the treatment of nonunion in long bones: a retrospective study

BACKGROUND

Nonunion of long bone fractures is a significant complication following surgical fixation, with an incidence ranging from 5% to 10%. Surgical intervention is the standard treatment for nonunions, but it may come with potential complications. Nonoperative approaches, such as Extracorporeal Shockwave Therapy (ESWT), have been advocated as alternatives.

METHODS

The retrospective study, conducted between January 2004 and January 2018, 91 patients who underwent ESWT for tibia or femur nonunions were included. Nonunion was defined based on radiographic criteria and clinical symptoms. The nonunion morphology was categorized as hypertrophic, oligotrophic, or atrophic. ESWT was administered using the OssaTron device in a single treatment session. Bony union was defined as the presence of bridging callus over fracture site with more than three-fourths of the circumference in both planes within the 12-month postoperative period.

RESULTS

The study included 91 patients, with an overall union rate of 62.6%. Higher healing rate was observed in trophic nonunion(69.9%) than atrophic nonunion(33.3%). Multivariate analysis identified the number of surgeries, maximum fracture gap, and atrophic nonunion as independent factors influencing the risk of fracture nonunion after ESWT. ROC curves were generated for these factors, providing more than one surgical interventions, and fracture gap greater than 3.94 mm as negative predictors of ESWT for long bone nonunions.

CONCLUSION

The study's primary findings suggest that ESWT is effective in achieving bony union for nonunions in long bones(62.6%). Despite the overall positive results, the study highlights that atrophic nonunions, larger fracture gaps more than 3.94 mm, and multiple surgeries are associated with poorer outcomes.

The induced membrane technique for the management of infected segmental bone defects

Aims

The aim of the present study was to assess the outcomes of the induced membrane technique (IMT) for the management of infected segmental bone defects, and to analyze predictive factors associated with unfavourable outcomes.

Methods

Between May 2012 and December 2020, 203 patients with infected segmental bone defects treated with the IMT were enrolled. The digital medical records of these patients were retrospectively analyzed. Factors associated with unfavourable outcomes were identified through logistic regression analysis.

Results

Among the 203 enrolled patients, infection recurred in 27 patients (13.3%) after bone grafting. The union rate was 75.9% (154 patients) after second-stage surgery without additional procedures, and final union was achieved in 173 patients (85.2%) after second-stage surgery with or without additional procedures. The mean healing time was 9.3 months (3 to 37). Multivariate logistic regression analysis of 203 patients showed that the number (≥ two) of debridements (first stage) was an independent risk factor for infection recurrence and nonunion. Larger defect sizes were associated with higher odds of nonunion. After excluding 27 patients with infection recurrence, multivariate analysis of the remaining 176 patients suggested that intramedullary nail plus plate internal fixation, smoking, and an allograft-to-autograft ratio exceeding 1:3 adversely affected healing time.

Conclusion

The IMT is an effective method to achieve infection eradication and union in the management of infected segmental bone defects. Our study identified several risk factors associated with unfavourable outcomes. Some of these factors are modifiable, and the risk of adverse outcomes can be reduced by adopting targeted interventions or strategies. Surgeons can fully inform patients with non-modifiable risk factors preoperatively, and may even use other methods for bone defect reconstruction.

Orthobiologics in delayed union and non-union of adult long bones fractures: A systematic review

Background

Fracture healing poses a significant challenge in orthopedics. Successful regeneration of bone is provided by mechanical stability and a favorable biological microenvironment. This systematic review aims to explore the clinical application of orthobiologics in treating aseptic delayed union and non-union of long bones in adults.

Methods

A systematic review was conducted following the Preferred Reporting Items for Systematic Review and Meta-Analyses (PRISMA) guidelines. Three databases were explored, with no date restrictions, using keywords related to orthobiologics and delayed union and non-union. Eligible studies included human clinical studies in English, with available full texts, examining orthobiologics such as platelet-rich plasma (PRP), mesenchymal stem cells (MSCs), and bone morphogenetic protein (BMPs) for treating aseptic delayed unions and non-unions in adults. Animal studies, in vitro research, and studies on non-unions due to congenital defects, tumors or infections were excluded.

Results

The initial search identified 9417 studies, with 20 ultimately included in the review. These studies involved 493 patients affected by non-union and 256 patients affected by delayed union, with an average age respectively of 40.62 years and 41.7 years. The mean follow-up period was 15.55 months for non-unions and 8.07 months for delayed unions. PRP was the most used orthobiologic, and outcomes were evaluated through time to union, functional scores, and clinical examinations. The results indicated that orthobiologics, especially PRP, tended to yield better outcomes compared to surgical procedures without biological factors.

Conclusion

This systematic review suggests that orthobiologics, such as PRP, BMPs, and MSCs, can be effective and safe in the management of delayed union and non-union fractures. These biological treatments have the potential to improve union rates, reduce healing times, and enhance functional outcomes in patients with non-union fractures. Further research is essential to refine treatment protocols and determine the most suitable orthobiologic for specific patient populations and fracture types.

Application of double plate fixation combined with Masquelet technique for large segmental bone defects of distal tibia: a retrospective study and literature review

BACKGROUND

There is no effective consensus on the choice of internal fixation method for the Masquelet technique in the treatment of large segmental bone defects of the distal tibia. Thus, the study aimed to investigate the outcomes of the Masquelet technique combined with double plate fixation in the treatment of large segmental bone defects.

METHODS

This was a retrospective study involving 21 patients with large segmental bone defects of the distal tibia who were treated between June 2017 and June 2020. The length of bone defect ranged from 6.0 cm to 11 cm (mean, 8.19 cm). In the first stage of treatment, following complete debridement, a cement spacer was placed to induce membrane formation. In the second stage, double plate fixation and autologous cancellous bone grafting were employed for bone reconstruction. Each patient's full weight-bearing time, bone healing time, and Iowa ankle score were recorded, and the occurrence of any complications was noted.

RESULTS

All patients were followed up for 16 to 26 months (mean, 19.48 months). The group mean full weight-bearing time and bone healing time after bone grafting were 2.41 (± 0.37) months and 6.29 (± 0.66) months, respectively. During the treatment, one patient had a wound infection on the medial side of the leg, so the medial plate was removed. The wound completely healed after debridement without any recurrence. After extraction of iliac bone for grafting, one patient had a severe iliac bone defect, which was managed by filling the gap with a cement spacer. Most patients reported mild pain in the left bone extraction area after surgery. The postoperative Iowa ankle score range was 84-94 (P < 0.05). In this cohort, 15 cases were rated as "excellent", and 6 cases as "good" on the Iowa ankle scoring system.

CONCLUSION

The Masquelet technique combined with double plate fixation is a safe and effective method for the treatment of large segmental bone defects of the distal tibia.

Principles and Evaluation of Bony Unions

Nonunion is a common and costly problem. Unfortunately, there is no widely agreed upon and standardized definition for nonunion. The evaluation of bony union should start with a thorough history and physical examination. The clinician should consider patient-dependent as well as patient-independent characteristics that may influence the rate of healing and evaluate the patient for physical examination findings suggestive of bony union and infection. Radiographs and clinical examination can help confirm a diagnosis of union. When the diagnosis is in doubt, however, advanced imaging modalities as well as laboratory studies can help a surgeon determine when further intervention is necessary.

Suppression of DNMT2/3 by proinflammatory cytokines inhibits CtBP1/2-dependent genes to promote the occurrence of atrophic nonunion

Failure of bone healing after fracture often results in nonunion, but the underlying mechanism of nonunion pathogenesis is poorly understood. Herein, we provide evidence to clarify that the inflammatory microenvironment of atrophic nonunion (AN) mice suppresses the expression levels of DNA methyltransferases 2 (DNMT2) and 3A (DNMT3a), preventing the methylation of CpG islands on the promoters of C-terminal binding protein 1/2 (CtBP1/2) and resulting in their overexpression. Increased CtBP1/2 acts as transcriptional corepressors that, along with histone acetyltransferase p300 and Runt-related transcription factor 2 (Runx2), suppress the expression levels of six genes involved in bone healing: BGLAP (bone gamma-carboxyglutamate protein), ALPL (alkaline phosphatase), SPP1 (secreted phosphoprotein 1), COL1A1 (collagen 1a1), IBSP (integrin binding sialoprotein), and MMP13 (matrix metallopeptidase 13). We also observe a similar phenomenon in osteoblast cells treated with proinflammatory cytokines or treated with a DNMT inhibitor (5-azacytidine). Forced expression of DNMT2/3a or blockage of CtBP1/2 with their inhibitors can reverse the expression levels of BGLAP/ALPL/SPP1/COL1A1/IBSP/MMP13 in the presence of proinflammatory cytokines. Administration of CtBP1/2 inhibitors in fractured mice can prevent the incidence of AN. Thus, we demonstrate that the downregulation of bone healing genes dependent on proinflammatory cytokines/DNMT2/3a/CtBP1/2-p300-Runx2 axis signaling plays a critical role in the pathogenesis of AN. Disruption of this signaling may represent a new therapeutic strategy to prevent AN incidence after bone fracture.

Delivery of Growth Factors to Enhance Bone Repair

The management of critical-sized bone defects caused by nonunion, trauma, infection, malignancy, pseudoarthrosis, and osteolysis poses complex reconstruction challenges for orthopedic surgeons. Current treatment modalities, including autograft, allograft, and distraction osteogenesis, are insufficient for the diverse range of pathology encountered in clinical practice, with significant complications associated with each. Therefore, there is significant interest in the development of delivery vehicles for growth factors to aid in bone repair in these settings. This article reviews innovative strategies for the management of critical-sized bone loss, including novel scaffolds designed for controlled release of rhBMP, bioengineered extracellular vesicles for delivery of intracellular signaling molecules, and advances in regional gene therapy for sustained signaling strategies. Improvement in the delivery of growth factors to areas of significant bone loss has the potential to revolutionize current treatment for this complex clinical challenge.

Treatment of infected bone defects with the induced membrane technique

Aims

This study aimed to evaluate the effectiveness of the induced membrane technique for treating infected bone defects, and to explore the factors that might affect patient outcomes.

Methods

A comprehensive search was performed in PubMed, Embase, and the Cochrane Central Register of Controlled Trials databases between 1 January 2000 and 31 October 2021. Studies with a minimum sample size of five patients with infected bone defects treated with the induced membrane technique were included. Factors associated with nonunion, infection recurrence, and additional procedures were identified using logistic regression analysis on individual patient data.

Results

After the screening, 44 studies were included with 1,079 patients and 1,083 segments of infected bone defects treated with the induced membrane technique. The mean defect size was 6.8 cm (0.5 to 30). After the index second stage procedure, 85% (797/942) of segments achieved union, and 92% (999/1,083) of segments achieved final healing. The multivariate analysis with data from 296 patients suggested that older age was associated with higher nonunion risk. Patients with external fixation in the second stage had a significantly higher risk of developing nonunion, increasing the need for additional procedures. The autografts harvested from the femur reamer-irrigator-aspirator increased nonunion, infection recurrence, and additional procedure rates.

Conclusion

The induced membrane technique is an effective technique for treating infected bone defects. Internal fixation during the second stage might effectively promote bone healing and reduce additional procedures without increasing infection recurrence. Future studies should standardize individual patient data prospectively to facilitate research on the affected patient outcomes.

Management of aseptic nonunions and severe bone defects: let us get this thing healed!

Effective nonunion and bone defect management requires consideration of multiple potential contributing factors including biomechanics, biology, metabolic, and patient factors. This article reviews these factors as well as several potential nonunion or bone defect treatments including bone grafts, bone graft substitutes, the induced membrane technique, and distraction osteogenesis. A summary of these concepts and guidelines for an overall approach to management are also provided.

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.

Nail breakage in patients with hypertrophic pseudoarthrosis after subtrochanteric femur fracture: treatment with exchanging nail and decortication

In this study, we aimed to show the results of exchange nail and decortication in patients whose subtrochanteric femur fractures were treated with intramedullary nails and subsequently developed fracture nonunion and nail breakage com- plications. This study consisted of patients presenting with subtrochanteric femur fractures between January 2013 and April 2019 who underwent surgery and later experienced nail breakage due to hypertrophic nonunion. There were a total of 10 patients aged 26-62 years (Avg 40,30, SD: 9,989). Nine patients were smokers, and 1 patient had diabetes and hypertension. Three patients were admitted to the trauma center due to a car accident and 7 patients were admitted because of a fall. The infection parameters of all patients were normal. All patients had pathological movement complications and pain at the fracture site. Preoperatively, medulla diameter was measured with standard radiography in all patients. The diameters of the old nails applied to the patients ranged from 10 to 12 mm, and the diameters of the newly applied nails ranged from 14 to 16 mm. The fracture lines of all patients were opened to remove the broken nails, and decortication was performed. No additional autograft or allograft was applied to any patient. Union was achieved in all patients. We conclude that the use of larger diameter nails in conjunction with decortication will prevent nail breakage, improve healing and provide early union in patients with subtrochanteric femur fractures with hypertrophic pseudoarthrosis.

Bone Healing Gone Wrong: Pathological Fracture Healing and Non-Unions-Overview of Basic and Clinical Aspects and Systematic Review of Risk Factors

Bone healing is a multifarious process involving mesenchymal stem cells, osteoprogenitor cells, macrophages, osteoblasts and -clasts, and chondrocytes to restore the osseous tissue. Particularly in long bones including the tibia, clavicle, humerus and femur, this process fails in 2-10% of all fractures, with devastating effects for the patient and the healthcare system. Underlying reasons for this failure are manifold, from lack of biomechanical stability to impaired biological host conditions and wound-immanent intricacies. In this review, we describe the cellular components involved in impaired bone healing and how they interfere with the delicately orchestrated processes of bone repair and formation. We subsequently outline and weigh the risk factors for the development of non-unions that have been established in the literature. Therapeutic prospects are illustrated and put into clinical perspective, before the applicability of biomarkers is finally discussed.

Long Non-Coding RNAs Within Macrophage-Derived Exosomes Promote BMSC Osteogenesis in a Bone Fracture Rat Model

Purpose

To investigate the effect of macrophage exosomal long non-coding (lnc)RNAs on bone mesenchymal stem cell (BMSC) osteogenesis and the associated mechanism.

Methods

Rat BMSCs and spleen macrophages were co-cultured with serum derived from the fracture microenvironment of rat tibia. BMSC osteogenesis was evaluated using Alizarin red staining and the expression of BMP-2, RUNX2, OPN, and OC mRNA. BMSC osteogenesis was evaluated after co-culture with macrophages stimulated using hypoxic conditions or colony-stimulating factor (CSF). The uptake of macrophage-derived exosomes by BMSCs was evaluated using the exosome uptake assay. High-throughput sequencing and bioinformatics analyses were performed to identify key lncRNAs in the macrophage exosomes. The effect of lncRNA expression levels on BMSC osteogenesis was also assessed using a lncRNA overexpression plasmid and siRNA technology. M1 and M2 macrophages were distinguished using flow cytometry and the key exosomal lncRNA was detected by in situ hybridization.

Results

In the fracture microenvironment, macrophages (stimulated using either hypoxia or CSF) significantly increased the osteogenic ability of BMSCs. We showed that BMSCs assimilated macrophage-derived vesicles and that the inhibition of exosomal secretion significantly attenuated the macrophage-mediated induction of BMSC osteogenesis. The hypoxia condition led to the up-regulation of 310 lncRNAs and the down-regulation of 575 lncRNAs in macrophage exosomes, while CSF stimulation caused the up-regulation of 557 lncRNAs and the down-regulation of 407 lncRNAs. In total, 108 lncRNAs were co-up-regulated and 326 lncRNAs were co-down-regulated under both conditions. We eventually identified LOC103691165 as a key lncRNA that promoted BMSC osteogenesis and was expressed at similar levels in both M1 and M2 macrophages.

Conclusion

In the fracture microenvironment, M1 and M2 macrophages promoted BMSC osteogenesis by secreting exosomes containing LOC103691165.

3D-Printing for Critical Sized Bone Defects: Current Concepts and Future Directions

The management and definitive treatment of segmental bone defects in the setting of acute trauma, fracture non-union, revision joint arthroplasty, and tumor surgery are challenging clinical problems with no consistently satisfactory solution. Orthopaedic surgeons are developing novel strategies to treat these problems, including three-dimensional (3D) printing combined with growth factors and/or cells. This article reviews the current strategies for management of segmental bone loss in orthopaedic surgery, including graft selection, bone graft substitutes, and operative techniques. Furthermore, we highlight 3D printing as a technology that may serve a major role in the management of segmental defects. The optimization of a 3D-printed scaffold design through printing technique, material selection, and scaffold geometry, as well as biologic additives to enhance bone regeneration and incorporation could change the treatment paradigm for these difficult bone repair problems.

ON Path: outpatient nonunion pathway for lower-extremity nonunions

Objectives

The purpose of this study was to assess the safety and efficacy of outpatient and short-stay surgical nonunion treatment by incorporating minimally invasive surgical techniques, multimodal pain control, and a modernized postoperative protocol.

Design

Retrospective case series.

Setting

Tertiary referral hospital and hospital outpatient department.

Patients

All consecutive nonunion surgeries performed by 1 surgeon between 2014 and 2019 were identified. Outpatient and short-stay surgeries for patients with nonunion of the tibia and femur were eligible (n = 50).

Intervention

Outpatient and short-stay surgical nonunion treatment by incorporating minimally invasive surgical techniques, multimodal pain control, and a modernized postoperative protocol.

Main Outcome Measurements

Length of stay, postoperative emergency department visits, all complications, reoperations, and time to union.

Results

Fifty patients were eligible, with 32 male patients (64%) and an average age of 46.5 years. The patient cohort consisted of 28 femur (56%) and 22 tibia (44%) nonunions. The average length of stay was 0.36 days. Seven patients (14%) required reoperation, 6 patients because of deep infection and 1 patient because of painful implant removal. Four patients (8%) presented to the emergency department within 1 week of surgery. One patient requiring amputation and patients lost to follow-up were excluded from the union rate calculation. For the remaining patients (46/50), 100% (46/46) united their nonunion. The average time to radiographic union was 7.82 months.

Conclusions

An outpatient pathway is safe and effective for medically appropriate patients undergoing nonunion surgery. Outpatient nonunion surgery is a reasonable alternative that achieves similar outcomes compared with inpatient nonunion studies in the published literature.

Level of Evidence

IV.

Evaluation of the effect of preoperative hemoglobin level and proinflammatory factors on intertrochanteric fracture union

BACKGROUND

Intertrochanteric fractures are associated with high mortality and morbidity, so these patients should undergo fracture fixation surgery immediately. Despite surgery, the possibility of fracture fusion may not occur due to the association with various causes. Therefore, our aim is to investigate these factors (TNF‑a, IL‑1, Hb) and their effect on fracture union after fixation.

METHODS

From 2018 to 2020, at our orthopedic trauma center, 163 patients older than 50 years with intertrochanteric fractures underwent DHS fixation surgery. Patients were divided into anemic and non-anemic groups in terms of preoperative hemoglobin level (standard hemoglobin 11 mg/dl). For 3 months, patients were assessed for union and failure fixation criteria, levels of proinflammation (TNF‑α, IL-1) and level of hemoglobin.

RESULTS

The results show that out of 163 patients with fractures, at the time of initial admission, 74 patients had less than 11 hemoglobin g/dl. Patients with union fractures had higher hemoglobin levels than patients with non-union (11.71 ± 1.51 versus 11.24 ± 1.96), which was statistically significant between hemoglobin and union level (p = 0.030). At the end of the third visit (third month), 44 (59.5%) anemic patients received union completly, while among the patients with normal hemoglobin level, 32 (36%) received union bread, which was statistically significant (p = 0.003). There were no statistically significant differences between proinflammatory factors before surgery and 3 months after surgery (p > 0.05).

CONCLUSION

Due to the effect of anemia and proinflammatory factors in the process of healing fractures and bone formation and creating musculoskeletal balance, low hemoglobin level before surgery has a significant effect on fracture union and failure of fixation. So it is recommended to correct this anemia in these patients before surgery and during follow-up.

Ultrasound-guided injection of platelet-rich plasma or cord blood platelet-rich plasma in nonunion: a randomized controlled trial

Aim: To compare the ability of autologous platelet-rich plasma (PRP) and cord blood PRP (PRPc) to accelerate bone healing. Patients & methods: 71 patients with mechanically stable nonunion were treated weekly (3 consecutive weeks) with ultrasound-guided percutaneous injections of PRP or PRPc in a controlled randomized clinical trial. The primary outcome was healing (12 months) and secondary outcomes were radiological evolution (2 and 6 months) and changes in pain intensity (6 months). Results & conclusion: Bone consolidation was assessed over time without significant differences between PRP and PRPc treatment. In patients with persistent nonunion, pain perception decreased more after PRP treatment. PRPc appears to be a valid alternative when specific clinical conditions suggest avoiding the use of autologous blood products.

Clinical Application of Adipose Derived Stem Cells for the Treatment of Aseptic Non-Unions: Current Stage and Future Perspectives-Systematic Review

Fracture non-union is a challenging orthopaedic issue and a socio-economic global burden. Several biological therapies have been introduced to improve traditional surgical approaches. Among these, the latest research has been focusing on adipose tissue as a powerful source of mesenchymal stromal cells, namely, adipose-derived stem cells (ADSCs). ADSC are commonly isolated from the stromal vascular fraction (SVF) of liposuctioned hypodermal adipose tissue, and their applications have been widely investigated in many fields, including non-union fractures among musculoskeletal disorders. This review aims at providing a comprehensive update of the literature on clinical application of ADSCs for the treatment of non-unions in humans. The study was performed according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA). Only three articles met our inclusion criteria, with a total of 12 cases analyzed for demographics and harvesting, potential manufacturing and implantation of ADSCs. The review of the literature suggests that adipose derived cell therapy can represent a promising alternative in bone regenerative medicine for the enhancement of non-unions and bone defects. The low number of manuscripts reporting ADSC-based therapies for long bone fracture healing suggests some critical issues that are discussed in this review. Nevertheless, further investigations on human ADSC therapies are needed to improve the knowledge on their translational potential and to possibly achieve a consensus on their use for such applications.

Treatment of Recalcitrant Femoral Shaft Nonunion With Medial Femoral Condyle Pedicled Autograft: Technical Trick

SUMMARY

Nonunited fractures of the femoral shaft and distal femur are usually successfully addressed with stabilization with or without autogenous bone grafting. For the small subset of these problems that prove recalcitrant to front-line treatment, a pedicled medial femoral condyle (MFC) bone flap can provide a source of vascularized autograft with minimal donor site morbidity. The MFC has gained recent widespread adoption as a free vascularized bone transfer, and here, we present a surgical technique and retrospective analysis of patients treated with a pedicled MFC technique. This serves as a useful treatment option for these difficult problems and may be especially helpful in low resource environments or where microsurgical anastomosis is not feasible.

Clinical and Patient-Reported Outcomes After Hybrid Russe Procedure for Scaphoid Nonunion

Background: Hybrid Russe technique for the treatment of scaphoid nonunion with humpback deformity has been described with a reported 100% union rate. We sought to evaluate the reproducibility of this technique. Methods: We completed a retrospective chart review of patients with a scaphoid waist nonunion and humpback deformity treated with the hybrid Russe technique from 2015 to 2019 with a minimum of 3-month follow-up. Twenty patients with 21 nonunions were included (mean follow-up: 7.0 months). Scapholunate angle was the primary outcome measure. Secondary outcomes included: intrascaphoid angle, radiolunate angle, pain on the visual analog scale (VAS), and Quick Disabilities of the Arm, Shoulder, and Hand (QuickDASH) score. Other variables included: time to computed tomography (CT) union, range of motion, and complications. Descriptive statistics were presented. Pre- and postoperative angles, VAS, and QuickDASH scores were evaluated with Wilcoxon signed rank tests. Results: The mean scapholunate angle improved -17.6° ± 6.4°. The mean intrascaphoid angle improved 28.2° ± 6.3°. The mean radiolunate angle improved 12.8° ± 8.8°. Of the 21 scaphoids, 20 (95%) demonstrated union on a CT scan. One patient was diagnosed with a nonunion. In total, 90% of patients noted symmetric range of motion compared with the contralateral side. The mean VAS pain score improved 6 ± 3 points. The mean QuickDASH score improved 10 ± 8 points. Complications (aside from nonunion) included 1 patient with persistent wrist pain that resolved with removal of hardware. Conclusions: The hybrid Russe technique for the treatment of scaphoid nonunions with humpback deformity demonstrates a 95% union rate. This technique is effective, reproducible, and may serve as an alternative to techniques that include structural grafts from distant sites.

Reamer-irrigator-aspirate versus bone marrow aspirate concentrate for osteoprogenitor cell retention and osteoinductive protein release on cancellous bone

Bone defects often require operative intervention with the use of bone graft. Two sources of autologous bone graft include reamer-irrigator-aspirate (RIA) and bone marrow aspirate concentrate (BMC). Osteoprogenitor cells and osteoconductive proteins have been identified in both sources. This study collected samples of these cells and proteins from a canine model and cultured them on human cancellous allograft bone blocks. Findings suggest that BMC may be preferred for indications that allow for delivery via injection, saturation of the patient's tissues, or an implanted scaffold, whereas RIA may be preferred when the biologic augment is delivered as a scaffold or graft.

Nerve growth factor promotes osteogenic differentiation of MC3T3-E1 cells via BMP-2/Smads pathway

BACKGROUND

Exogenous nerve growth factor (NGF) can induce osteogenic precursor cell differentiation and promote fracture healing. However, the molecular mechanism by which NGF induces osteogenesis is not well understood. BMP-2 has good osteogenic efficacy and is one of the most osteogenic-inducing growth factors known. Therefore, this study aimed to determine whether NGF induces osteogenic differentiation of mouse embryonic osteogenic precursor cell line MC3T3-E1 by BMP-2 and search further mechanisms of NGF on BMP-2.

METHODS

MC3T3-E1 cells were treated with NGF at a concentration gradient for indicated times, after which the cell viability was measured by CCK-8 kit. Osteogenic differentiation was detected with quantification of alkaline phosphatase (ALP) activity also visualized with ALP staining. The transcription and expression of relevant genes were detected by qPCR and western blotting, respectively. NGF's effect on BMP2 was studied with qPCR and luciferase reporter assay. The phosphorylation of Smads was probed with specific antibodies by western blotting, and the location of Smads was observed through immunofluorescence.

RESULTS

We found that NGF promoted proliferation and osteogenic differentiation of MC3T3-E1, increased the expression level of BMP-2, as well as the phosphorylation and nuclear translocation of Smad1/5/8. However, neutralization of BMP-2 with si-BMP-2 or BMP-2 signal inhibitors reversed NGF induced phosphorylation and nuclear translocation of Smad1/5/8, as well as the expression of Runx2, type I collagen, osteocalcin and osteopontin. In addition, si-BMP-2 abrogated NGF-induced ALP activity.

CONCLUSION

NGF induced osteogenic differentiation of MC3T3-E1 cells through BMP-2/Smads pathway and induction of Runx2. Our study would provide a theoretical basis for clinical treatment of fractures using NGF.

Non-union bone fractures

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

Platelet-Rich Plasma Combined With Autologous Grafting in the Treatment of Long Bone Delayed Union or Non-union: A Meta-Analysis

Background: Platelet-rich plasma (PRP) has been suggested as an emerging treatment for bone defects. However, whether PRP could enhance the therapeutic efficacy of autologous bone grafting for long bone delayed union or non-union remains unknown. A meta-analysis of randomized and non-randomized controlled trials (RCT and NRCT) was performed to summarize current evidence. Methods: Relevant RCTs and NRCTs comparing the influences of autologous bone grafting on healing of long bone delayed union or non-union with and without PRP were obtained by searching PubMed, Embase, Cochrane's Library, China National Knowledge Infrastructure, and WanFang databases from inception to September 10, 2020. A random-effect model was applied to pool the results with the incorporation of the potential heterogeneity. Subgroup analysis according to study design was also performed. Results: Six RCTs and two NRCTs with 420 patients were included. Compared to patients allocated to autologous bone grafting alone, those allocated to combined treatment with PRP and autologous bone grafting were not associated with higher rates of radiographic bone healing [risk ratio (RR): 1.06, 95% confidence interval (CI): 0.99-1.13, P = 0.09; I ² = 24%] or excellent/good posttreatment limb function (RR: 1.14, 95% CI: 0.95-1.37, P = 0.37; I ² = 0%) but was associated with a shorter healing time (mean difference: -1.35 months, 95% CI: -1.86 to -0.84, P < 0.001; I ² = 58%). Subgroup analysis according to study design showed similar results for the above outcomes (P-values for subgroup difference all >0.10). Conclusions: Combined treatment with PRP and autologous bone grafting may be effective to accelerate the healing of long bone delayed union or non-union compared to autologous bone grafting alone.

Infected Nonunion of the Tibia Due to Paenibacillus turicensis in a Healthy Young Adult After an All-Terrain Vehicle Accident

We present the case of a 19-year-old man with an open fracture of the tibia and fibula secondary to an accident with an all-terrain vehicle. He underwent operative excisional irrigation, debridement, and fixation on the day of injury. His course was complicated by nonunion of the tibia fracture. Infection is a common factor in fracture nonunion, even in patients who receive appropriate surgical and antimicrobial management. Paenibacillus turicensis, an organism adapted to survive in the environment via spore formation, was responsible for nonunion in our patient. A brief discussion of this unusual organism, fracture nonunion, and the role of infection in etiology of nonunion follows.

Do the successful revision surgery for humeral nonunion solve all the effects on health-related quality of life? A retrospective cohort study

Background

The aim of this study is to evaluate the effects of successful revision operation on health quality of life(QoL) and functional outcome in humeral nonunion patients.

Methods

This retrospective study included 62 patients with humeral nonunion from Northwest China, who were admitted to the Department of Trauma Surgery, Honghui Hospital between March 2013 and September 2019. The following data were retrospectively evaluated: demographic data, clinical data, imaging findings, and treatment methods. The QoL assessment indicators for humeral nonunion patients included the SF-12 mental component summary (MCS) and physical component summary (PCS),brief pain inventory-severity(BPI-S) and brief pain inventory-interference (BPI-I). The mayo elbow performance score (MEPS) was used to assess the elbow function of the patients.

Results

Successful revision surgery significantly improved the patient's PCS, MCS, BPI-S and BPI-I scores (p<0.001). According to the MEPS criteria, the excellent and good rates were 95.16% in this study. The impact of humeral nonunion on mental health was comparable with the reported impact of stroke and type II diabetes (p>0.05).The impact of post-op on physical health was comparable with the reported impact of COPD, silicosis, hypertension, barrentt’s esophagus and lower urinary tract symptoms(p>0.05).

Conclusion

Humeral nonunion is a devastating chronic medical condition that negatively affects both physical and mental health as well as quality of life. Although the effects of pain in the body can be completely relieved by treatment, the entire medical process may cause everlasting psychological trauma to the patient.

Closed Compression Nailing Using a New-Generation Intramedullary Nail without Autologous Bone Grafting for Humeral Shaft Nonunion

Introduction

Although the recommended treatment for humeral shaft nonunion is compression plating with autologous bone grafting, we treated a case of humeral shaft nonunion with an intramedullary nail (IMN) without bone grafting. Presentation of Case. Osteosynthesis with IMN was performed on a 24-year-old man with a humeral shaft fracture at another hospital. However, bony union was not obtained 1 year after the first surgery, and he was referred to our institution. We treated the nonunion with exchange nailing without autologous bone grafting using compression function of the nail, leading to bony union at 7 months postoperatively. At the final follow-up 2 years and 4 months postoperatively, the patient had full range of motion in the left shoulder and elbow joints. Discussion. Compression plating with autologous bone grafting is reported to be the gold standard for the treatment of humeral shaft nonunion. IMN is advantageous for minimal invasion; however, the conventional type of IMN cannot apply compression force between fragments and does not have sufficient stability against rotational force. In this case, we used an IMN that could apply compression between the fragments and which had rotational stability via many screws. We did not perform bone grafting because the current nonunion was adjudged to be biologically active, and we achieved good functional results.

Conclusion

We treated humeral shaft nonunion using IMN with compression, but without bone grafting, leading to successful clinical outcomes. This strategy might be an appropriate choice for the treatment of humeral shaft nonunion with biological activity.

Successful Arthroscopic Fixation of a Posterior Wall Acetabular Fracture Nonunion on a Patient With Femoroacetabular Impingement: A Case Report

CASE

This report presents the results of a hip arthroscopic technique that was used to treat an unusual posterior wall acetabular fracture nonunion. A 30-year-old man presented with 1 year of persistent left-sided buttock and groin pain with associated feeling of instability when climbing stairs. Magnetic resonance imaging demonstrated a small left acetabular posterior wall fracture nonunion. We describe outpatient treatment with reduction and cannulated screw fixation using arthroscopic techniques that permitted immediate partial weight bearing and achieved excellent outcomes at 1 year.

CONCLUSION

Arthroscopic fixation of an acetabular posterior wall fracture nonunion may be a feasible treatment option in select cases.

Toll-like receptor activation of equine mesenchymal stromal cells to enhance antibacterial activity and immunomodulatory cytokine secretion

OBJECTIVE

To evaluate effects of Toll-like and nucleotide-binding oligomerization domain (NOD)-like receptor (TLR, NLR) ligand stimulation of equine mesenchymal stromal cells (MSCs) on antibacterial and immunomodulatory properties in vitro.

STUDY DESIGN

Controlled laboratory study.

SAMPLE POPULATION

Equine bone-marrow-derived MSCs (three horses).

METHODS

MSCs were stimulated with TLR (polyinosinic:polycytidylic acid [pIC] and lipopolysaccharide [LPS]) and NLR agonists (γ-d-Glu-mDAP [IE-DAP]) for 2 h, and plated at 1 × 10⁵ cells/well 24 h. MSC-conditioned media (MSC-CM) were collected and assessed for antimicrobial peptide cathelicidin/LL-37 production, bactericidal action against multidrug-resistant planktonic and biofilm Staphylococcus aureus and neutrophil phagocytosis. Bacterial growth was measured by plating bacteria and counting viable colonies, reading culture absorbance, and live-dead staining with confocal microscopy imaging. Following initial comparison of activating stimuli, TLR3-agonist pIC protocols (cell density during activation and plating, culture time, %serum) were further optimized for bactericidal activity and secretion of interleukin-8 (IL-8), monocyte-chemoattractant-protein (MCP-1), and cathelicidin/LL37.

RESULTS

MSCs stimulation with pIC (p = .004) and IE-DAP (p = .03) promoted increased bactericidal activity, evidenced by reduced viable planktonic colony counts. PIC stimulation (2 × 10⁶ cells/ml, 2 h, 10 μg/ml) further suppressed biofilm formation (p = .001), enhanced neutrophil bacterial phagocytosis (p = .009), increased MCP-1 secretion (p < .0001), and enhanced cathelicidin/LL-37 production, which was apparent when serum concentration in media was reduced to 1% (p = .01) and 2.5% (p = .05).

CONCLUSION

TLR-3 pIC MSCs activation was most effective to enhance antibacterial and cytokine responses, which were affected by serum reduction.

CLINICAL SIGNIFICANCE

In vitro TLR-3 activation of equine MSCs tested here may be a strategy to improve antibacterial properties of MSCs to treat antibiotic-resistant infections.

The Fate of Patients After a Staged Nonunion Procedure for Known Infection

OBJECTIVES

To determine the factors associated with successful union and eradication of infection in the setting of staged procedures to treat obviously infected nonunions of long bones. We hypothesize that patients with positive intraoperative cultures obtained at the time of definitive surgery for infected nonunions are more likely to have persistent nonunion than those with negative cultures.

DESIGN

Multicenter retrospective review.

SETTING

Eight academic Level 1 trauma centers.

PATIENTS/PARTICIPANTS

Patients who underwent staged management for obviously infected nonunion of a long bone.

MAIN OUTCOME MEASUREMENTS

For each patient, initial fracture management, management of retained implants, number of debridements, grafting, bacteriology, antibiotic course, bone defect management, soft-tissue coverage, and definitive surgery performed were reviewed.

RESULTS

A total of 134 patients were treated with staged procedures for obviously infected nonunion of a long bone (mean age 49 years, 60% open fractures, and mean follow-up 22 months). During definitive procedures, 120 patients had intraoperative cultures taken with 43% having positive cultures. For culture-positive patients, 41 patients achieved eventual union and 10 had persistent nonunion. Of 69 culture-negative patients, 66 achieved eventual union and 3 had persistent nonunion. The number of patients with union versus persistent nonunion was statistically significant between culture-positive and culture-negative groups (P = 0.015).

CONCLUSIONS

Management of infected nonunion in long bones with staged treatments before definitive fixation are beneficial but ultimately less effective when performed in the setting of positive bacterial cultures at the time of definitive management.

LEVEL OF EVIDENCE

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

The induced membrane technique for bone defects: Basic science, clinical evidence, and technical tips

The clinical management of large bone defects continues to be a difficult clinical problem to manage for treating surgeons. The induced membrane technique is a commonly employed strategy to manage these complex injuries and achieve bone union. Basic science and clinical evidence continue to expand to address questions related to the biology of the membrane and how interventions may impact clinical outcomes. In this review, we discuss the basic science and clinical evidence for the induced membrane technique as well as provide indications for the procedure and technical tips for performing the induced membrane technique.

Scope and Limits of Teriparatide Use in Delayed and Nonunions: A Case Series

Nonunion is known to occur in up to 10% of all bone fractures. Until recently, the treatment options considered in cases of delayed union and nonunion focused on revision surgery and improvement of local healing. Lately, teriparatide has been introduced as an osteoanabolic factor that induces fracture healing in cases with delayed or nonunions. We report on a series of five cases of delayed and nonunions treated with teriparatide: delayed unions of an atypical femoral fracture, of a multifragmentary clavicle fracture, and of a periprosthetic humeral fracture; nonunion of a tibial and fibular fracture; and infected nonunion of a tibial and fibular fracture. Based on this series, the indications and limits of application of teriparatide in cases of impaired fracture healing are discussed. Due to the “off-label” character of this application, informed consent, and cost coverage from the healthcare insurance must be obtained prior to treatment. In our experience and according to the limited existing literature, teriparatide is a safe feasible treatment in cases of delayed and nonunions with a reasonable need of resources. While adequate biomechanical stability remains the cornerstone of fracture healing, as well as healing of nonunions, teriparatide could help avoid repetitive surgeries, especially in atrophic delayed and nonunions, as well as in patients with impaired fracture healing undergoing bisphosphonate therapy. There is an urgent need for widely accepted definitions, standardized protocols, as well as further clinical trials in the field of impaired fracture healing.

The induced membrane technique for the management of long bone defects

AIMS

The purpose of this study was to: review the efficacy of the induced membrane technique (IMT), also known as the Masquelet technique; and investigate the relationship between patient factors and technique variations on the outcomes of the IMT.

METHODS

A systematic search was performed in CINAHL, The Cochrane Library, Embase, Ovid MEDLINE, and PubMed. We included articles from 1 January 1980 to 30 September 2019. Studies with a minimum sample size of five cases, where the IMT was performed primarily in adult patients (≥ 18 years old), in a long bone were included. Multivariate regression models were performed on patient-level data to determine variables associated with nonunion, postoperative infection, and the need for additional procedures.

RESULTS

A total of 48 studies were included, with 1,386 cases treated with the IMT. Patients had a mean age of 40.7 years (4 to 88), and the mean defect size was 5.9 cm (0.5 to 26). In total, 82.3% of cases achieved union after the index second stage procedure. The mean time to union was 6.6 months (1.4 to 58.7) after the second stage. Our multivariate analysis of 450 individual patients showed that the odds of developing a nonunion were significantly increased in those with preoperative infection. Patients with tibial defects, and those with larger defects, were at significantly higher odds of developing a postoperative infection. Our analysis also demonstrated a trend towards the inclusion of antibiotics in the cement spacer having a protective effect against the need for additional procedures.

CONCLUSION

The IMT is an effective management strategy for complex segmental bone defects. Standardized reporting of individual patient data or larger prospective trials is required to determine the optimal implementation of this technique. This is the most comprehensive review of the IMT, and the first to compile individual patient data and use regression models to determine predictors of outcomes. Cite this article: Bone Joint J 2020;102-B(12):1723-1734.

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

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

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

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

Nonunion - consensus from the 4th annual meeting of the Danish Orthopaedic Trauma Society

Nonunions are a relevant economic burden affecting about 1.9% of all fractures. Rather than specifying a certain time frame, a nonunion is better defined as a fracture that will not heal without further intervention.

Successful fracture healing depends on local biology, biomechanics and a variety of systemic factors. All components can principally be decisive and determine the classification of atrophic, oligotrophic or hypertrophic nonunions. Treatment prioritizes mechanics before biology.

The degree of motion between fracture parts is the key for healing and is described by strain theory. If the change of length at a given load is > 10%, fibrous tissue and not bone is formed. Therefore, simple fractures require absolute and complex fractures relative stability.

The main characteristics of a nonunion are pain while weight bearing, and persistent fracture lines on X-ray.

Treatment concepts such as ‘mechanobiology’ or the ‘diamond concept’ determine the applied osteosynthesis considering soft tissue, local biology and stability. Fine wire circular external fixation is considered the only form of true biologic fixation due to its ability to eliminate parasitic motions while maintaining load-dependent axial stiffness. Nailing provides intramedullary stability and biology via reaming. Plates are successful when complex fractures turn into simple nonunions demanding absolute stability. Despite available alternatives, autograft is the gold standard for providing osteoinductive and osteoconductive stimuli.

The infected nonunion remains a challenge. Bacteria, especially staphylococcus species, have developed mechanisms to survive such as biofilm formation, inactive forms and internalization. Therefore, radical debridement and specific antibiotics are necessary prior to reconstruction.

Cite this article: EFORT Open Rev 2020;5:46-57. DOI: 10.1302/2058-5241.5.190037

Nonunited Lower Extremity Fractures Initially Repaired Outside the Developed Western World Develop a High Rate of Postoperative Complications After Nonunion Repair

OBJECTIVES

To evaluate the clinical and functional outcomes after operative repair of nonunited lower extremity fractures initially repaired outside the developed Western world.

DESIGN

Retrospective analysis of prospectively collected data.

SETTING

Academic medical center.

PATIENTS/PARTICIPANTS

From September 2004 through February 2017, 227 patients who underwent operative repair of a lower extremity fracture nonunion were prospectively enrolled in a research registry. All patients underwent previous fracture surgery and had at least 12 months of postoperative follow-up.

INTERVENTION

Repair of lower extremity fracture nonunion.

MAIN OUTCOME MEASUREMENTS

Postoperative complications, reoperation rate, time to union, and functional outcomes were assessed using the Short Musculoskeletal Function Assessment and Visual Analog Scale pain scores. Univariate and multivariate analyses were performed to evaluate the differences in patients who underwent initial fracture repair outside the developed Western world as opposed to within the United States.

RESULTS

Twenty-one patients (9.3%) underwent initial fracture repair outside the developed Western world. These patients had a greater incidence of infected nonunions (47.6% vs. 23.3%; P = 0.015) and failure of a previous implant at the time of presentation (52.4% vs. 22.8%; P = 0.003) than those initially managed within the United States. This cohort also experienced a greater rate of postoperative complications after nonunion repair (23.8% vs. 6.3%; P = 0.016). The geographic location of initial fracture repair was not associated with postoperative Short Musculoskeletal Function Assessment scores or Visual Analog Scale pain scores after controlling for possible confounding variables.

CONCLUSIONS

Patients who present with a nonunited lower extremity fracture initially repaired outside the developed Western world experience a high rate of postoperative complications after fracture nonunion repair but can expect good short- and long-term functional outcomes.

LEVEL OF EVIDENCE

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

Cell-Based Therapies for the Treatment of Fractures

Ongoing studies investigating fracture healing have uncovered and allowed investigators to gain a better understanding of where the variety of cells, which participate in this process, originate, and how they communicate as well as how they can be enhanced to successfully heal a fracture when the process has slowed or failed completely. This brief review will highlight some of the recent findings regarding the role the immune system in fracture healing and how these cells communicate with each other during the healing process. In addition, two 2 methods that have recently been shown to be promising techniques in supporting fracture when it stalls or reversing the process, when the fracture has failed to heal, will also be described.

Hip Fracture Nonunions: Diagnosis, Treatment, and Special Considerations in Elderly Patients

In the United States, more than 300,000 hip fractures occur annually in the elderly population with associated significant morbidity and mortality. Both intracapsular and extracapsular hip fractures have inherent treatment challenges and therefore are at risk of nonunion complications. A systematic assessment including radiographic, metabolic, and infectious evaluations should be completed for all patients suspected of nonunion. Failed internal fixation of intracapsular hip fractures is typically treated with arthroplasty, while extracapsular proximal femur nonunions may be amenable to revision internal fixation or arthroplasty. While not a classic hip fracture, bisphosphate associated subtrochanteric femur fractures affect a similar patient population and are historically difficult to treat. Atypical subtrochanteric femur fractures are at increased risk of nonunion given the altered biologic environment secondary to bisphosphonate use; therefore adjuvant therapies may be beneficial in setting of revision fixation. Having a thorough understanding of nonunion risks, recognition, evaluation, and treatment is necessary for appropriate patient care.

Therapy of aseptic nonunions with parathyroid hormone

The absence of osseous consolidation of a fracture for 9 or more months with no potential to heal is defined as nonunion. Both for the patient and from a socioeconomic point of view, nonunions represent a major problem. Hypertrophic, vital nonunions are distinguished from atrophic avital ones. Risk factors for a delayed fracture healing are insufficient immobilisation, poor adaptation of the fracture surfaces or residual instability, interposition of soft tissue within the fracture gap, as well as circulation disturbances and infections. The incidence of nonunions after fractures of the long bones lies between 2.6 and 16% depending on the surgical technique used. In human and animal studies, a positive effect of parathyroid hormone (PTH) on fracture healing has been shown. PTH has a direct stimulatory effect on osteoblasts and osteoclasts. In addition, it appears to influence the effect of osseous growth factors. In this prospective study, 32 patients with nonunions were treated with teriparatide to investigate the effects of PTH on fracture healing. Definitive healing of the nonunions following PTH treatment could be observed in 95% of the cases.