Treatment of recalcitrant atrophic non-union of the humeral shaft with BMP-7, autologous bone graft and hydroxyapatite pellets

Bone Morphogenic Protein for Upper Extremity Fractures: A Systematic Review

BACKGROUND

This review discusses success, time to healing, and complications of bone morphogenic proteins (BMPs) 7 and 2 in treating upper extremity nonunions.

METHODS

Systematic review identified 26 of 479 studies that met inclusion criteria. Publications described application of BMPs to acute and chronic upper extremity delayed unions/nonunions. Unions, complications, patient demographics, and fracture/healing patterns were pooled and analyzed.

RESULTS

Nonunions treated with BMP-7 (n=302) involved the humerus (64%), forearm (22%), clavicle (11%), and hand/wrist (3%), with prior surgical correction attempted in 84%. Nonunions treated with BMP-2 (n=96) involved the humerus (58%), hand/wrist (27%), forearm (14%), and clavicle (1%), with prior surgical correction attempted in all. Most nonunions (80%) were present for over 12 months before BMP application. Union rates of BMP-7 varied according to site: hand/wrist (95%), humerus (74%), forearm (29%), and clavicle (6.2%) nonunions achieved union as defined by study authors in 232 days (confidence interval=96-369, Q<0.001) on average. While not significant across studies, BMP-2 union rates were 71% of hand/wrist and 75% of humerus nonunions. Comparison of the BMPs demonstrates different proportions of success in humerus and hand/wrist fractures (P<.001) but not forearm fractures (P<.77) and longer time to radiographic union with BMP-7 (P<.011).

CONCLUSIONS

Most hand/wrist and humerus nonunions treated with BMP-7 and BMP-2 achieved union, with significant similarity among BMP-7 studies not observed in BMP-2 studies. Nonunions treated with BMP-7 have longer healing times yet similar complication rates compared with BMP-2. Overall, BMPs are an effective adjunct to fracture healing with acceptable complication profile.

Therapeutic Efficacy and Safety of Osteoinductive Factors and Cellular Therapies for Long Bone Fractures and Non-Unions: A Meta-Analysis and Systematic Review

Background: Long bone fractures display significant non-union rates, but the exact biological mechanisms implicated in this devastating complication remain unclear. The combination of osteogenetic and angiogenetic factors at the fracture site is an essential prerequisite for successful bone regeneration. The aim of this study is to investigate the results of the clinical implantation of growth factors for intraoperative enhancement of osteogenesis for the treatment of long bone fractures and non-unions. Methods: A systematic literature review search was performed according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines in the PubMed and Web of Science databases from the date of inception of each database through to 10 January 2022. Specific inclusion and exclusion criteria were applied in order to identify relevant studies reporting on the treatment of upper and lower limb long bone non-unions treated with osteoinductive or cellular factors. Results: Overall, 18 studies met the inclusion criteria and examined the effectiveness of the application of Bone Morphogenetic Proteins-2 and -7 (BMPs), platelet rich plasma (PRP) and mesenchymal stem cells (MSCs). Despite the existence of limitations in the studies analysed (containing mixed groups of open and close fractures, different types of fractures, variability of treatment protocols, different selection criteria and follow-up periods amongst others), their overall effectiveness was found significantly increased in patients who received them compared with the controls (I² = 60%, 95% CI = 1.59 [0.99–2.54], Z =1.93, p = 0.05). Conclusion: Administration of BMP-2 and -7, PRP and MSCs were considered effective and safe methods in fracture treatment, increasing bone consolidation, reducing time to repair and being linked to satisfactory postoperative functional scores.

Application of BMP in Bone Tissue Engineering

At present, bone nonunion and delayed union are still difficult problems in orthopaedics. Since the discovery of bone morphogenetic protein (BMP), it has been widely used in various studies due to its powerful role in promoting osteogenesis and chondrogenesis. Current results show that BMPs can promote healing of bone defects and reduce the occurrence of complications. However, the mechanism of BMP in vivo still needs to be explored, and application of BMP alone to a bone defect site cannot achieve good therapeutic effects. It is particularly important to modify implants to carry BMP to achieve slow and sustained release effects by taking advantage of the nature of the implant. This review aims to explain the mechanism of BMP action in vivo, its biological function, and how BMP can be applied to orthopaedic implants to effectively stimulate bone healing in the long term. Notably, implantation of a system that allows sustained release of BMP can provide an effective method to treat bone nonunion and delayed bone healing in the clinic.

Risk Factors for Development of a Recalcitrant Femoral Nonunion: A Single Surgeon Experience in 122 Patients

OBJECTIVES

The goals of the study were (1) to document the healing rates of femoral nonunions stratified by those that healed as intended, healed after a subsequent intervention, and those that did not heal; (2) to report the prevalence of recalcitrant femoral nonunions and (3) to identify specific demographic, injury, and treatment-related risk factors for the development of a recalcitrant nonunion.

DESIGN

Longitudinal observational cohort study.

SETTING

Academic Level 1 trauma center.

PATIENTS/PARTICIPANTS

One hundred twenty-two femoral nonunions treated with either a plate or intramedullary nail by a single surgeon between 1991 and 2018.

INTERVENTION

Bivariate and multivariate regression analysis were performed to identify specific demographic, injury, and treatment factors in patients who developed a recalcitrant nonunion.

RESULTS

Although 83.6% of the femoral nonunions eventually healed, only 66% "healed as intended" with 17.2% requiring 1 or more additional procedures to consolidate and 16.4% of nonunions failing to unite. There were no statistically significant differences in the recalcitrance rate when we compared treatment with conventional versus locked plates or primary versus exchange nailing. Risk factors for developing a recalcitrant nonunion were deep infection, current smokers, metabolic bone disease, and patients who had undergone 3 or more prior surgical procedures.

CONCLUSIONS

The use of both intramedullary nails and modern plates were associated with a high rate of recalcitrance. Infection, current smokers, metabolic bone disease, and 3 or more prior surgical procedures were predictors for the development of a recalcitrant nonunion.

LEVEL OF EVIDENCE

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

Growth Factors, Carrier Materials, and Bone Repair

This chapter provides an overview of the growth factors active in bone regeneration and healing. Both normal and impaired bone healing are discussed, with a focus on the spatiotemporal activity of the various growth factors known to be involved in the healing response. The review highlights the activities of most important growth factors impacting bone regeneration, with a particular emphasis on those being pursued for clinical translation or which have already been marketed as components of bone regenerative materials. Current approaches the use of bone grafts in clinical settings of bone repair (including bone grafts) are summarized, and carrier systems (scaffolds) for bone tissue engineering via localized growth factor delivery are reviewed. The chapter concludes with a consideration of how bone repair might be improved in the future.

Supramolecular self-assembling peptides to deliver bone morphogenetic proteins for skeletal regeneration

Recombinant human bone morphogenetic proteins (BMPs) have shown clinical success in promoting bone healing, but they are also associated with unwanted side effects. The development of improved BMP carriers that can retain BMP at the defect site and maximize its efficacy would decrease the therapeutic BMP dose and thus improve its safety profile. In this review, we discuss the advantages of using self-assembling peptides, a class of synthetic supramolecular biomaterials, to deliver recombinant BMPs. Peptide amphiphiles (PAs) are a broad class of self-assembling peptides, and the use of PAs for BMP delivery and bone regeneration has been explored extensively over the past decade. Like many self-assembling peptide systems, PAs can be designed to form nanofibrous supramolecular biomaterials in which molecules are held together by non-covalent bonds. Chemical and biological functionality can be added to PA nanofibers, through conjugation of chemical moieties or biological epitopes to PA molecules. For example, PA nanofibers have been designed to bind heparan sulfate, a natural polysaccharide that is known to bind BMPs and potentiate their signal. Alternatively, PA nanofibers have been designed to synthetically mimic the structure and function of heparan sulfate, or to directly bind BMP specifically. In small animal models, these bio-inspired PA materials have shown the capacity to promote bone regeneration using BMP at doses 10-100 times lower than established therapeutic doses. These promising results have motivated further evaluation of PAs in large animal models, where their safety and efficacy must be established before clinical translation. We conclude with a discussion on the possiblity of combining PAs with other materials used in orthopaedic surgery to maximize their utility for clinical translation.

Healing the Index Humeral Shaft Nonunion: Risk Factors for Development of a Recalcitrant Nonunion in 125 Patients

BACKGROUND

Humeral shaft nonunions are challenging to treat, and those that require >1 surgical procedure in order for a nonunion to heal are termed recalcitrant. Most studies on nonunion have evaluated the union rate independent of the number of procedures required to achieve union. The aims of the present study were (1) to compare the healing rates after the index operation for the treatment of a nonunion with conventional versus locked plating with or without graft augmentation, (2) to report the prevalence of recalcitrant nonunion, and (3) to identify risk factors that predict a recalcitrant nonunion.

METHODS

We performed a retrospective analysis of a prospectively collected database of 125 humeral shaft nonunions treated with open reduction and plate fixation by a single surgeon over 25 years. Univariate and multivariate regression analyses were performed to compare healing rates by type of plate fixation and biological augmentation and to identify demographic, injury, and treatment-related risk factors for the development of a recalcitrant nonunion.

RESULTS

One hundred and five patients (84%) had healing after the index procedure for the treatment of nonunion. Twenty patients (16.0%) required secondary procedures and were defined as having a recalcitrant nonunion. Eight of these patients (6.4% of the overall group) healed after the secondary interventions, and 12 (9.6% of the overall group) had a failure to unite. There were no significant differences in healing rates between conventional and locked plates or between the types of bone graft (autogenous or recombinant human bone morphogenetic protein). Risk factors for the development of a recalcitrant nonunion were plate fixation of the acute humeral fracture, a history of deep infection, and ≥2 prior procedures.

CONCLUSIONS

Plate fixation with bone graft augmentation remains a successful method for the treatment of humeral shaft nonunions. Neither plate type nor graft type reduced the risk of a recalcitrant nonunion. Factors that predicted a recalcitrant nonunion were operative fixation of the acute fracture with a plate, a history of deep infection, and ≥2 surgical procedures.

LEVEL OF EVIDENCE

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

Physical stimulations and their osteogenesis-inducing mechanisms

Physical stimulations such as magnetic, electric and mechanical stimulation could enhance cell activity and promote bone formation in bone repair process via activating signal pathways, modulating ion channels, regulating bonerelated gene expressions, etc. In this paper, bioeffects of physical stimulations on cell activity, tissue growth and bone healing were systematically summarized, which especially focused on their osteogenesis-inducing mechanisms. Detailedly, magnetic stimulation could produce Hall effect which improved the permeability of cell membrane and promoted the migration of ions, especially accelerating the extracellular calcium ions to pass through cell membrane. Electric stimulation could induce inverse piezoelectric effect which generated electric signals, accordingly up-regulating intracellular calcium levels and growth factor synthesis. And mechanical stimulation could produce mechanical signals which were converted into corresponding biochemical signals, thus activating various signaling pathways on cell membrane and inducing a series of gene expressions. Besides, bioeffects of physical stimulations combined with bone scaffolds which fabricated using 3D printing technology on bone cells were discussed. The equipments of physical stimulation system were described. The opportunities and challenges of physical stimulations were also presented from the perspective of bone repair.

Recalcitrant aseptic atrophic non-union of the shaft of the humerus after failure of surgical treatment: management by excision of non-union, bone grafting and stabilization by LCP in different modes

Non-union of the humeral shaft is infrequently noticed after surgical fixation. Sixty eight patients whose osteosynthesis of humeral shaft had failed leading to non-union were identified over a duration of 10 years from (January 2006 to December 2015). Clinical and radiographical follow-up was available for 64 patients (4 patients were lost for follow-up), with a mean age of 58 years (range 25-78 years). All patients had aseptic atrophic non-union of either: proximal shaft (n=12), mid shaft (n=38), and lower shaft (n=14). All these patients had failure of primary fixation, with a minimum duration from 36 to 110 weeks. Non-unions were operated by excision of non-union, autogenous bone grafting and osteosynthesis by locking compression plating. Adequate fixation of non-union with bone grafting was achieved in all patients. All non-unions healed well at an average of 16 weeks (range 6-36 weeks). The mean length of follow-up was 120 weeks (range 60-250 weeks). The mean range of movements following healing of non-union was forward flexion of 140°, external rotation and internal rotation of 30° at shoulder and average fixed flexion deformity of 10° and flexion of 130° at elbow. Two patients had postoperative radial nerve palsy because of neuropraxia, which recovered in eight weeks. Three patient developed superficial infections at the iliac crest, which settled with antibiotics, dressings in 3 weeks time and two patients had some discomfort over the fibular graft harvest site. In all patients complete clinical and radiological union was achieved with satisfactory outcome in terms of relief of symptoms and functional improvement in the range of movements. The main points in surgical treatment were complete excision of non-union, correction of deformity, use of plenty of corticocancellous graft, furthermore the use of intramedullary fibula and osteosynthesis by long locking compression plating in different modes of fixation provided good to excellent results and clinical outcome.

Management of resistant distal femur non-unions with allograft strut and autografts combined with osteosynthesis in a series of 22 patients

INTRODUCTION AND PURPOSE

Challenges to the surgeon in managing cases of resistant non-union of the distal femur include poor bone stock, disuse osteopenia and joint contractures. Procedures varying from simple bone grafting to megaprosthesis revision have been described. We successfully managed such cases using our technique of combining cortical allograft struts to augment the defect in the femoral condyle coupled with autogenous iliac crest bone grafting and locking plate osteosynthesis.

MATERIALS AND METHODS

Between April 2012 and May 2014, 22 patients who presented with resistant nonunions of the distal femur following initial surgery were managed using this technique. Cortical allograft struts were taken from the tissue bank of our institution. All patients were followed up post operatively and their time to union was noted. Functional outcome was calculated using LEFS (Lower extremity functional score). The average follow up of all our patients was 24 months.

RESULTS

All patients went on to achieve complete bony union. The average union time was 6.2 months (5 to 8 months). One patient who was a diabetic had superficial infection post operatively which was treated successfully with IV antibiotics. Average knee flexion was 110 degrees (80 to 130 degrees). The mean LEFS score was 72 (59 to 79).

CONCLUSION

Combing a locking plate fixation with the bone grafting technique of using an allograft strut to support the metaphyseal medial bone defect and autografts gives a good union and a good functional outcome in the management of resistant non-unions of the distal femur by enhancing the biology and providing a good structural support to the distal femur.

Effectiveness of exchange K-nail and augmented plating in aseptic femoral diaphyseal non-union

BACKGROUND

Femoral diaphyseal non-unions present difficult scenario to manage. There are multiple options but most of them still report varying incidences of failure. We combined the principles of augmented plating and exchange nailing and aim to study the effectiveness of this technique.

METHOD

A retrospective study at a tertiary trauma centre was conducted. Seventy patients (60 men, 10 women), average age 40.7±15.27 years (range 18-81 years) with diaphyseal femoral fracture non-unions treated between July 2010 and January 2015 were reviewed. The average interval between first and the last surgery was 18.07±17.65 months (range 4-96 months). Forty six patients had hypertrophic non-union and 24 patients had atrophic non-union. Twenty one patients had undergone a prior surgery for non-union, 13 dynamisation, 4 bone grafting, 1 augmented plating and 3 exchange nailing. Non-unions were treated with implant removal, freshening of bone edges and exchange K-nailing and augmented plating. Autologous bone grafting and raising of osteoperiosteal flaps was done in all cases. Outcome measures were radiographic evidence of fracture union at minimum three out of four cortices, knee range of motion as compared to opposite knee, and study of complications.

RESULTS

All patients demonstrated radiographic evidence of fracture union with an average time of 16.77±2.38 weeks (range 12-26 weeks). Mean knee range of motion of unaffected limb was 126±9.76° (range 90-140°) while in operated limb it was 121.1±11.36° (range 80-140°), p>0.01. Patients with hypertrophic non-unions, prior surgery for non-union and supra- or infra-isthmal non-unions had shorter union time. Two patients had superficial infection which was managed by superficial debridement and two patients had pain at proximal nail tip site which was managed by anti-inflammatory medication. None of the patients required additional surgery for implant removal.

CONCLUSION

Exchange K nailing with Bone graft and additional plating technique for non-union diaphyseal femur fracture achieved good union rates with minimal complication. In our series none of the patient required revision and the technique probably will further minimise the revision rates compared to current options for non-union femur.

Closing the gap: a novel technique for humeral shaft nonunions using cup and cone reamers

INTRODUCTION

Nonunion following closed treatment of humeral shaft fracture is estimated to be 5.5%. Many surgical techniques have been described to address humeral shaft nonunion including: open reduction, internal fixation (ORIF) with compression plating and bone graft, dual plating, cortical strut allograft and autograft, and adding biologic augmentation (BMP). The current standard of care includes ORIF with compression plating and bone grafting, but even this technique has an approximated 10% failure rate. We describe a novel surgical technique using cup and cone reamers, which were originally designed for metatarsophalangeal or metacarpalphalangeal arthrodesis. Cup and cone reamers are the appropriate size for mid-shaft, transverse humeral nonunions to ensure ideal apposition of healthy, bleeding bone.

METHODS AND PATIENTS

We retrospectively reviewed 3 patients with nonunion of the midshaft humerus which were treated with the cup and cone technique and a large fragment LCDC plate. An anterolateral approach was used in 2 cases and a posterior in the other. After exposure of fracture ends, 24-mm hemispherical convex and concave reamers were then used to ream the proximal and distal ends in order to create a "cup and cone" articulation of the fracture ends. All patients were followed for a minimum of 6 months with a mean follow-up of 12 months.

RESULTS

All patients treated with this technique achieved union, reported zero pain and full functional outcome. Specifically, patients had a mean age of 36.3 and the mean interval between injury and time to surgery was 11.5 months. Two of the patients presented with nonunions after attempted closed treatment and the other patient had 3 prior surgeries for infected nonunion. Union was achieved at a mean of 12 weeks.

CONCLUSION

To our knowledge, the use of cup and cone reamers for nonunion of the humerus has never been described. We describe a simple and effective technique for humeral shaft nonunions which has been successful in both septic and hypertrophic nonunions, as well as from multiple approaches-both anterolateral and posterior.