Efficacy of a Cellular Bone Allograft for Foot and Ankle Arthrodesis and Revision Nonunion Procedures

Radiographical outcomes of a cellular based allograft following foot/ankle arthrodesis in patients with risk for non-union

Morbidity associated with autograft harvest has led to the need for alternative bone grafts during fusion surgical procedures. The purpose of this study is to evaluate the efficacy of a cellular bone allograft (CBA) in patients who underwent foot/ankle fusion surgery. Retrospective data of patients who underwent foot/ankle arthrodesis using a CBA between XXXX and XXXX were collected from a single site. Patients were at least 18 years of age at the time of surgery and had ankle/foot surgery with Trinity ELITE CBA as the primary or only bone graft. Patients' radiographic union was assessed at three (3) months, six (6) months, nine (9) months, and twelve (12) months. Twenty-two (22) patients and 29 joints were evaluated. The mean age and BMI of the cohort were 54±9yrs and 30.5±6kg/m2, respectively. The surgical indications were degenerative joint diseases, trauma, and arthritis. All patients except one had at least one risk factor for non-union. At 12 months, 21 of the 22 patients (95%) attained successful fusion with an average time of 6 months. In addition, there was a 100% fusion among patients with prior failed fusion, nicotine use, diabetes, neuropathy, and osteoporosis. There was no significant difference in time to fusion between patients with non-union risk factor(s) ≤ 1 and ≥ 2 (p=0.71). No complication or adverse event was reported following the surgery. The use of CBA resulted in high fusion among patients with the risk of non-union. CBA is a viable bone graft substitute for autograft in foot/ankle arthrodesis procedures.

CT-Verified Union Rate Following Arthrodesis of Ankle, Hindfoot, or Midfoot: A Systematic Review

BACKGROUND

Ankle, hindfoot, and midfoot arthrodesis surgeries are standard procedures performed in orthopaedics to treat pain and functional disabilities. Although fusions can effectively improve pain and quality of life, nonunions remain a significant concern for surgeons. With the increased availability of computed tomography (CT), more surgeons rely on this modality for increased accuracy in determining whether a fusion was successful. The objective of this study was to report the rates of CT-confirmed fusion following ankle, hindfoot, or midfoot arthrodesis.

METHODS

A systematic review was performed using EMBASE, Medline, and Cochrane central register from January 2000 to March 2020. Inclusion criteria included studies with adults (<18 years) that received 1 or multiple fusions of the ankle, hindfoot, or midfoot. At least 75% of the study cohort must have been evaluated by CT postoperatively. Basic information was collected, including journal, author, year published, and level of evidence. Other specific information was collected, including patient risk factors, fusion site, surgical technique and fixation, adjuncts, union rates, criteria for successful fusion (%), and time of CT. Once data were collected, a descriptive and comparative analysis was performed.

RESULTS

Included studies (26, n = 1300) had an overall CT-confirmed fusion rate of 78.7% (69.6-87.7). Individual joints had an overall fusion rate of 83.0% (73-92.9). The highest rate of union was in the talonavicular joint (TNJ).

CONCLUSION

These values are lower than previous studies, which found the same procedures to have greater than 90% fusion rates. With these updated figures, as confirmed by CT, surgeons will have better information for clinical decision making and when having informed consent conversations.

A Retrospective Analysis of Outcomes From Foot and Ankle Arthrodesis and Open Reduction and Internal Fixation Using Cellular Bone Allograft Augmentation

BACKGROUND

ViviGen is an allogeneic cellular bone matrix product containing lineage-committed bone cells, and can be used as an alternative to autograft bone or other augments to aid in arthrodesis or to enhance bony healing in open reduction and internal fixation (ORIF) procedures.

METHODS

This study included 153 consecutive patients undergoing ankle, midfoot, or hindfoot arthrodesis or ORIF procedures from January 2017 to October 2018, in which an allogeneic cellular bone matrix product was used to aid in bony healing. Retrospective chart review identified patient demographic factors and medical comorbidities and evaluated clinical and radiographic data to determine fusion/union rate and complications.

RESULTS

The overall fusion rate for the arthrodesis cohort was 97/113 (85.8%). The overall complication rate in this cohort was 22/113 (19.5%). Smokers had significantly lower rates of fusion compared with nonsmokers (P = .01). The observed bony healing rate for the ORIF cohort was 19/22 (86.4%), with a complication rate of 3/22 (13.6%).

CONCLUSION

With satisfactory fusion rates and relatively few complications, our findings suggest that ViviGen is a safe and efficacious alternative to other forms of bone graft augmentation for fusion and ORIF procedures about the foot and ankle. Further study is needed to compare the efficacy of ViviGen with autograft bone and other augments.

LEVELS OF EVIDENCE

Level IV: Case series.

Treatment of Infected Nonunions With Bone Defects Using Autologous Bone Graft and Absorbable Antibiotic-Loaded Calcium Sulfate-Hydroxyapatite Paste

BACKGROUND

Revision surgery in the presence of infection carries high risks. We describe our results using a new technique to treat these challenging problems. We treated infected nonunions with cavitary voids with adjuvant antibiotic loaded calcium sulfate-hydroxyapatite paste composite and autologous bone graft (ABG) layer technique coupled with stable fixation.

METHODS

Thirty consecutive patients who underwent revision foot and ankle surgery for an infected nonunion were prospectively studied. Following multidisciplinary team workup, surgical debridement and biopsies were undertaken. Bone voids were measured and classified according to containment and size. ABG was mixed and layered with an adjuvant antibiotic-loaded calcium sulfate-hydroxyapatite paste followed by surgical reconstruction including arthrodesis and fixation. Empirical and pathogen-specific antibiotics were instituted until intraoperative sample-specific antibiotics were identified and used. Patients were prospectively followed up for a minimum of 1 year.

RESULTS

The male-female ratio was 16:14, mean age was 51.3 years, and 23.3% smoked at definitive surgery. Void volume was <1 cm³ (n=9), 1-2 cm³ (n = 13), and >2 cm³ (n=8). No patients either were lost to follow-up or had a further infective episode at a mean of 38.3 months; 86.7% united with fusion on imaging. Four patients had radiographic evidence of nonunion; 3 were asymptomatic and 1 required revision surgery (void >2 cm³). Independent ambulation was achieved at an average of 12 weeks, at 1 year mean American Orthopaedic Foot & Ankle Society score was 77.7 (SD 9.59), and the Manchester-Oxford Foot Questionnaire reached an effect size >0.5 in all domains at 1 year following surgery. The union rate was independent of smoking status and vitamin D deficiency (P = .94).

CONCLUSION

Layered autologous bone grafting with adjuvant antibiotic-loaded calcium sulfate-hydroxyapatite paste has been shown to be effective and safe in revision arthrodesis, with low comorbidities in void gaps without infection recurrence.

Nonoperative and Operative Soft-Tissue and Cartilage Regeneration and Orthopaedic Biologics of the Foot and Ankle: An Orthoregeneration Network Foundation Review

Orthoregeneration is defined as a solution for orthopaedic conditions that harnesses the benefits of biology to improve healing, reduce pain, improve function, and optimally, provide an environment for tissue regeneration. Options include drugs, surgical intervention, scaffolds, biologics as a product of cells, and physical and electromagnetic stimuli. The goal of regenerative medicine is to enhance the healing of tissue after musculoskeletal injuries as both isolated treatment and adjunct to surgical management, using novel therapies to improve recovery and outcomes. Various orthopaedic biologics (orthobiologics) have been investigated for the treatment of pathology involving the foot and ankle (including acute traumatic injuries and fractures, tumor, infection, osteochondral lesions, arthritis, and tendinopathy) and procedures, including osteotomy or fusion. Promising and established treatment modalities include 1) bone-based therapies (such as cancellous or cortical autograft from the iliac crest, proximal tibia, and/or calcaneus, fresh-frozen or freeze-dried cortical or cancellous allograft, including demineralized bone matrix putty or powder combined with growth factors, and synthetic bone graft substitutes, such as calcium sulfate, calcium phosphate, tricalcium phosphate, bioactive glasses (often in combination with bone marrow aspirate), and polymers; proteins such as bone morphogenic proteins; and platelet-derived growth factors; 2) cartilage-based therapies such as debridement, bone marrow stimulation (such as microfracture or drilling), scaffold-based techniques (such as autologous chondrocyte implantation [ACI] and matrix-induced ACI, autologous matrix-induced chondrogenesis, matrix-associated stem cell transplantation, particulated juvenile cartilage allograft transplantation, and minced local cartilage cells mixed with fibrin and platelet rich plasma [PRP]); and 3) blood, cell-based, and injectable therapies such as PRP, platelet-poor plasma biomatrix loaded with mesenchymal stromal cells, concentrated bone marrow aspirate, hyaluronic acid, and stem or stromal cell therapy, including mesenchymal stem cell allografts, and adipose tissue-derived stem cells, and micronized adipose tissue injections. LEVEL OF EVIDENCE: Level V, expert opinion.

Glycyrrhizic Acid Promotes Osteogenic Differentiation of Human Bone Marrow Stromal Cells by Activating the Wnt/β-Catenin Signaling Pathway

Glycyrrhizic acid (GA) is a major triterpene glycoside isolated from liquorice root that has been shown to inhibit osteoclastogenesis. However, there have been no reports regarding the effect of GA on osteogenic differentiation. Therefore, this study was performed to explore the effects and mechanism of action of GA on osteogenesis. A CCK-8 array was used to assess cell viability. The osteogenic capability was investigated by real-time quantitative PCR, western blotting and immunofluorescence analyses. ALP staining and ARS were used to evaluate ALP activity and mineralization, respectively. GA-GelMA hydrogels were designed to verify the therapeutic effects of GA in vivo by radiographic analysis and histological evaluation. Our results show that GA had no significant influence on the viability or proliferation of human bone marrow stromal cells (hBMSCs). GA promoted osteogenic differentiation and enhanced calcium deposition. Furthermore, ratio of active β-catenin and total β-catenin protein increased after treatment with GA. Wnt/catenin signaling inhibitor partially attenuated the effects of GA on osteogenic differentiation. In a mouse femoral fracture model, GA-GelMA hydrogels accelerated bone healing. Our results show that GA promotes the osteogenic differentiation of hBMSCs by modulating the Wnt/β-catenin signaling pathway. GA-GelMA hydrogels promoted bone fracture healing. GA has potential as a cost-effective treatment of bone defects.

Allografts and Spinal Fusion

BACKGROUND

Back pain is a common chief complaint within the United States and is caused by a multitude of etiologies. There are many different treatment modalities for back pain, with a frequent option being spinal fusion procedures. The success of spinal fusion greatly depends on instrumentation, construct design, and bone grafts used in surgery. Bone allografts are important for both structural integrity and providing a scaffold for bone fusion to occur.

METHOD

Searches were performed using terms "allografts" and "bone" as well as product names in peer reviewed literature Pubmed, Google Scholar, FDA-510k approvals, and clinicaltrials.gov.

RESULTS

This study is a review of allografts and focuses on currently available products and their success in both animal and clinical studies.

CONCLUSION

Bone grafts used in surgery are generally categorized into 3 main types: autogenous (from patient's own body), allograft (from cadaveric or living donor), and synthetic. This paper focuses on allografts and provides an overview on the different subtypes with an emphasis on recent product development and uses in spinal fusion surgery.

Arthroscopic Contribution of Synthetic Graft in Tibiotalocalcaneal Arthroscopic Fusions

Nonunion is a frequent complication of tibiotalocalcaneal arthrodesis. The risk of nonunion increases significantly for those patients with systemic comorbidities and smokers. The purpose of this article is to show the proper way to supplement our arthroscopic fusion surgeries with biomaterial (peptide-15) graft. We have achieved an increase in consolidation rates in complex patient cases. We can conclude that this is a simple and reproducible technique.

Is adjunction of advanced platelet-rich fibrin (A-PRF) useful in first metatarsophalangeal joint arthrodesis? A retrospective cohort study

PURPOSE

First metatarsophalangeal (MTPJ1) fusion represents the gold standard treatment for end-stage hallux rigidus (HR). The aim of this study was to assess efficacy and safety of A-PRF in promoting union after MTPJ1 arthrodesis. Our hypothesis was that the use of A-PRF may reduce the non-union rate and the time to fusion in the treatment of HR.

METHODS

14 patients that had undergone MTPJ1 arthrodesis with A-PRF adjunction with 21 standard MTPJ1 fusions were retrospectively reviewed. The fusion rate and time to fusion (clinically and radiographically) were assessed at 6, 12 weeks and at the longest follow-up; the clinical status at final follow-up through forefoot AOFAS, EQ5d, SEFAS and VAS-pain scores; the complication rate.

RESULTS

At 6-weeks, bony union was achieved in 100% of patients in the A-PRF group compared to 70% in the control group, but this difference was not statistically significant (p=0.22). At final follow-up (41 months), union rate in the control group reached 92% (one non-union). AOFAS, VAS and EQ-5d scores showed similar results for the two groups (p=0.86, p=0.12 and p=0.61, respectively); only SEFAS score revealed a difference favoring the A-PRF group (p=0.04). No revision surgery or complication was recorded in any group.

CONCLUSIONS

A tendency for increased union rate was mainly found at 6 weeks in patients treated with MTPJ1 fusion associated to A-PRF compared to isolated fusion. The use of A-PRF was not associated with an increased complication rate at final follow-up.

LEVEL OF EVIDENCE

Level 3, therapeutic study, retrospective comparative study.

Exosomes in the Repair of Bone Defects: Next-Generation Therapeutic Tools for the Treatment of Nonunion

Nonunion with bone defects, a common complication after long bone fracture, is a major challenge for orthopaedic surgeons worldwide because of the high incidence rate and difficulties in achieving successful treatment. Bone defects are the main complications of nonunion. The conventional biological treatments for nonunion with bone defects involve the use of autologous bone grafts or bone graft substitutes and cell-based therapy. Traditional nonunion treatments have always been associated with safety issues and various other complications. Bone grafts have limited autologous cancellous bone and there is a risk of infection. Additionally, problems with bone graft substitutes, including rejection and stimulation of bone formation, have been noted, and the health of the stem cell niche is a major consideration in cell-based therapy. In recent years, researchers have found that exosomes can be used to deliver functional RNA and mediate cell-to-cell communication, suggesting that exosomes may repair bone defects by regulating cells and cytokines involved in bone metabolism. In this review, we highlight the possible relationships between risk factors for nonunion and exosomes. Additionally, we discuss the roles of exosomes in bone metabolism and bone regeneration.

The Use of Bone Grafts, Bone Graft Substitutes, and Orthobiologics for Osseous Healing in Foot and Ankle Surgery

Achieving fusion in osseous procedures about the foot and ankle presents unique challenges to the surgeon. Many patients have comorbidities that reduce osseous healing rates, and the limited space and high weightbearing demand placed on fusion sites makes the choice of bone graft, bone graft substitute, or orthobiologic agent of utmost importance. In this review, we discuss the essential characteristics of grafts, including their osteoconductive, osteoinductive, osteogenic, and angiogenic properties. Autologous bone graft remains the gold standard and contains all these properties. However, the convenience and lack of donor site morbidity of synthetic bone grafts, allografts, and orthobiologics, including growth factors and allogenic stem cells, has led to these being used commonly as augments.

What Is the Treatment "Algorithm" for Infection After Ankle or Hindfoot Arthrodesis?

RECOMMENDATION

There is no universal algorithm for addressing the infected ankle or subtalar arthrodesis. A potential algorithm created by consensus is.

LEVEL OF EVIDENCE

Consensus.

DELEGATE VOTE

Agree: 100%, Disagree: 0%, Abstain: 0% (Unanimous, Strongest Consensus).

Small Molecules Enhance Scaffold-Based Bone Grafts via Purinergic Receptor Signaling in Stem Cells

The need for bone grafts is high, due to age-related diseases, such as tumor resections, but also accidents, risky sports, and military conflicts. The gold standard for bone grafting is the use of autografts from the iliac crest, but the limited amount of accessible material demands new sources of bone replacement. The use of mesenchymal stem cells or their descendant cells, namely osteoblast, the bone-building cells and endothelial cells for angiogenesis, combined with artificial scaffolds, is a new approach. Mesenchymal stem cells (MSCs) can be obtained from the patient themselves, or from donors, as they barely cause an immune response in the recipient. However, MSCs never fully differentiate in vitro which might lead to unwanted effects in vivo. Interestingly, purinergic receptors can positively influence the differentiation of both osteoblasts and endothelial cells, using specific artificial ligands. An overview is given on purinergic receptor signaling in the most-needed cell types involved in bone metabolism-namely osteoblasts, osteoclasts, and endothelial cells. Furthermore, different types of scaffolds and their production methods will be elucidated. Finally, recent patents on scaffold materials, as wells as purinergic receptor-influencing molecules which might impact bone grafting, are discussed.

Use of Patient-Specific 3D-Printed Titanium Implants for Complex Foot and Ankle Limb Salvage, Deformity Correction, and Arthrodesis Procedures

BACKGROUND

The advancement of 3D printing technology has allowed for the use of custom-designed implants for difficult-to-treat foot and ankle pathologies. This study reports on the radiographic and functional outcomes of a case series of patients treated with patient-specific 3D-printed titanium implants.

METHODS

Fifteen consecutive patients treated with custom-designed 3D-printed implant cages for severe bone loss, deformity correction, and/or arthrodesis procedures were included in this study. A minimum of 1 year of clinical and radiographic follow-up was required. No patients were lost to follow-up. Patients completed a visual analog scale for pain, the Foot and Ankle Ability Measure Activities of Daily Living score, and the American Orthopaedic Foot & Ankle Society Score outcomes questionnaires preoperatively and at most recent follow-up. All patients had postoperative radiographs and computed tomography (CT) scans to assess bony incorporation. The mean age was 53.3 years (range, 22-74 years) with a mean follow-up of 22 months (range, 12-48 months) for these 15 patients.

RESULTS

Radiographic fusion verified by CT scan occurred in 13 of 15 patients. There was significant improvement in pain and all functional outcome score measures. All patients who went on to fusion were satisfied with their surgery. There were 2 failures, consisting of 1 infection and 1 nonunion, with an overall clinical success rate of 87%.

CONCLUSION

These patients demonstrated the successful use of patient-specific 3D-printed titanium implants to treat complex large bony defects, deformities, and arthrodesis procedures. These implants offer surgeons a novel and promising approach to treat both lower extremity pain and deformity that is not always available with current techniques.

LEVEL OF EVIDENCE

Level IV, retrospective case series.

Diaphyseal long bone nonunions - types, aetiology, economics, and treatment recommendations

The intention of the current article is to review the epidemiology with related socioeconomic costs, pathophysiology, and treatment options for diaphyseal long bone delayed unions and nonunions. Diaphyseal nonunions in the tibia and in the femur are estimated to occur 4.6-8% after modern intramedullary nailing of closed fractures with an even much higher risk in open fractures. There is a high socioeconomic burden for long bone nonunions mainly driven by indirect costs, such as productivity losses due to long treatment duration. The classic classification of Weber and Cech of the 1970s is based on the underlying biological aspect of the nonunion differentiating between "vital" (hypertrophic) and "avital" (hypo-/atrophic) nonunions, and can still be considered to represent the basis for basic evaluation of nonunions. The "diamond concept" units biomechanical and biological aspects and provides the pre-requisites for successful bone healing in nonunions. For humeral diaphyseal shaft nonunions, excellent results for augmentation plating were reported. In atrophic humeral shaft nonunions, compression plating with stimulation of bone healing by bone grafting or BMPs seem to be the best option. For femoral and tibial diaphyseal shaft fractures, dynamization of the nail is an atraumatic, effective, and cheap surgical possibility to achieve bony consolidation, particularly in delayed nonunions before 24 weeks after initial surgery. In established hypertrophic nonunions in the tibia and femur, biomechanical stability should be addressed by augmentation plating or exchange nailing. Hypotrophic or atrophic nonunions require additional biological stimulation of bone healing for augmentation plating.