Recombinant human platelet-derived growth factor-BB and beta-tricalcium phosphate (rhPDGF-BB/β-TCP): an alternative to autogenous bone graft

Subtalar Arthrodesis with Use of Adipose-Derived Cellular Bone Matrix Compared with Autologous Bone Graft: A Multicenter, Randomized Controlled Trial

UPDATE

This article was updated on November 7, 2019, because of a previous error. On page 1909, in the section entitled "Discussion," the sentence that had read "Radiographic nonunion rates of 69.2% and 45.6% were observed at 6 months for ACBM and autograft, respectively, as measured on CT scans; however, these nonunion rates do account for patients who were considered to have attained fusion according to traditional methods, including absence of pain and swelling and presence of arthrodesis on radiographs" now reads "Radiographic nonunion rates of 69.2% and 45.6% were observed at 6 months for ACBM and autograft, respectively, as measured on CT scans; however, these nonunion rates do not account for patients who were considered to have attained fusion according to traditional methods, including absence of pain and swelling and presence of arthrodesis on radiographs."An erratum has been published: J Bone Joint Surg Am. 2019 XXX.

BACKGROUND

Subtalar arthrodesis effectively treats subtalar joint arthritis when other interventions have failed. Nonunion is a known complication of subtalar arthrodesis, with reported rates ranging from 5% to 45%. Historically, open arthrodesis has been performed with use of autologous bone graft; however, there are inherent disadvantages to autologous bone graft, including donor-site morbidity. Mesenchymal stem cells, when placed on a cellular scaffold, have shown promise as an alternative to autologous bone graft. The purpose of this multicenter, randomized controlled trial was to assess the safety and efficacy of an adipose-derived cellular bone matrix (ACBM) composite made with live cells compared with autograft in subtalar arthrodesis.

METHODS

A total of 140 patients were enrolled in a prospective, randomized (1:1) controlled trial performed at 6 clinical sites in the U.S. End points, including radiographic, clinical, and functional outcomes, were assessed over 2 years of follow-up.

RESULTS

A total of 109 patients underwent arthrodesis with ACBM (52 patients) and autograft (57 patients). At 6 months, fusion was achieved in 16 patients (30.8%) in the ACBM group and 31 patients (54.4%) in the autograft group as measured on computed tomography (p = 0.024), and in 41 patients (78.8%) in the ACBM group and 50 patients (87.7%) in the autograft group as assessed on clinical and radiographic evaluation (p = 0.213). Quality-of-life outcome measures demonstrated significant functional improvement from baseline for both groups. Fewer cases of serious adverse events occurred in the autograft group (10.5%) compared with the ACBM group (23.1%) (p = 0.078).

CONCLUSIONS

In patients who require subtalar arthrodesis, the use of ACBM demonstrated lower rates of radiographic fusion compared with treatment with autograft. The nonunion rate in the autologous group, as measured on computed tomography, was high. Good clinical outcomes were achieved in spite of the high non-union rates.

LEVEL OF EVIDENCE

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

Regenerative Materials for Surgical Reconstruction: Current Spectrum of Materials and a Proposed Method for Classification

Chronic wound management is an enormous economic strain and quality-of-life issue for patients. Current treatments are ineffective or expensive and invasive. Materials (native and artificial) can act as the basis to enhance wound repair but often fall short of complete healing. The therapeutic index of materials have often been enhanced by combining them with drug or biologic elution technologies. Combination of materials with living drugs (cells) presents a new paradigm for enhancing therapy. Cell material interaction and therapeutic output will depend on variables ascribed to the living drug as well as variables ascribed to the underlying matrix. In this article, we review medical matrices currently approved by the US Food and Drug Administration (FDA) that would likely be the first generation of materials to be used in this manner. Currently there are hundreds of different materials on the market. Identification of the right combinations would benefit from a classification scheme to group materials with similar composition or derivation. We provide a classification scheme and FDA documentation references that should provide researchers and clinicians a starting point for testing these materials in the laboratory and rapidly transitioning cell therapies to the bedside.

Orthobiologics

Use of orthobiologics in sports medicine and musculoskeletal surgery has gained significant interest. However, many of the commercially available and advertised products are lacking in clinical evidence. Widespread use of products before fully understanding their true indications may result in unknown adverse outcomes and may also lead to increased health care costs. As more products become available, it is important to remain judicial in use and to practice evidence-based medicine. Likewise, it is important to continue advances in research in hopes to improve surgical outcomes. This article reviews clinical evidence behind common orthobiologics in the treatment of foot and ankle pathology.

Biomaterials for topical and transdermal drug delivery in reconstructive transplantation

Lifelong systemic immunosuppression remains the biggest challenge in vascularized composite allotransplantation (VCA) due to the adverse effects it causes. Since VCA is a life-enhancing procedure as compared with solid organ transplant which is life-saving; one needs to weigh the benefits and risks carefully. Thus, there is a huge unmet clinical need to design biomaterial-based vehicles that can deliver drugs more efficiently, topically and locally to eliminate adverse effects of systemic immune suppression. This review discusses several biomaterial-based systems that have been carefully designed, conceived and attempted to make VCA a more patient compliant approach. Variety of promising preclinical studies has shown the feasibility of the approaches, and clinical trials are required to bridge the gap. Several challenges for the future and new approaches have been discussed.

Recombinant Human Platelet-Derived Growth Factor BB in Combination With a Beta-Tricalcium Phosphate (rhPDGF-BB/β-TCP)-Collagen Matrix as an Alternative to Autograft

BACKGROUND

Joint arthrodesis often employs autograft to promote union; graft harvesting can lead to perioperative morbidity. A Canadian randomized controlled trial (RCT) demonstrated that recombinant human platelet-derived growth factor BB homodimer (rhPDGF-BB) combined with beta-tricalcium phosphate (β-TCP)-collagen was a safe, effective alternative to autograft. This multicenter North American RCT compared the safety and efficacy of rhPDGF-BB/β-TCP-collagen with autograft for ankle and hindfoot fusion. Subclassification using propensity scores (PS) incorporated patients from previous trials for enhanced statistical power for noninferiority testing and broader review of treatments.

METHODS

Patients requiring ankle or hindfoot arthrodesis and supplemental bone graft were treated with rhPDGF-BB/β-TCP-collagen (n = 69) or autograft (n = 35). Outcomes included joint fusion on computed tomography (24 weeks), clinical healing status, visual analog scale (VAS) pain, Short-Form 12 (SF-12), American Orthopaedic Foot & Ankle Society (AOFAS) Ankle-Hindfoot Scale, and Foot Function Index (FFI) scores over 52 weeks. PS methodology addressed potential selection bias arising from pooling data among these patients and 2 previous RCTs with similar inclusion criteria, surgical techniques, graft harvest techniques, and outcomes. All 132 rhPDGF-BB/β-TCP-collagen-treated patients and 167 of 189 candidate autograft-treated controls were selected for comparison by an independent statistician blinded to outcomes.

RESULTS

In the PS subclassification, 68.1% treatment patients and 68.4% controls achieved >50% osseous bridging at fusion sites. Clinical healing status was achieved in 84.8% of treated patients and 90.7% of controls at 52 weeks. Clinical, functional, and quality of life results demonstrated noninferiority of rhPDGF-BB/β-TCP-collagen to autograft. Safety-related outcomes were equivalent.

CONCLUSION

PS subclassification analysis of 3 RCTs demonstrated that rhPDGF-BB/β-TCP-collagen was as effective as autograft for ankle and hindfoot fusions, with less pain and morbidity than treatment with autograft.

LEVEL OF EVIDENCE

Level I, prospective randomized study.

Optimizing Results in Diabetic Charcot Reconstruction

Reconstruction of the diabetic Charcot foot can be a challenge even for the most experienced foot and ankle surgeon. The first portion of this article discusses the preoperative evaluation with an emphasis on factors that can be modified before surgical reconstruction to help optimize surgical results. The second portion of the article focuses on intraoperative methods and techniques to help improve postoperative outcomes. Surgeons should strive to provide high-quality, cost-effective care by optimizing patient selection and perioperative care. Objective measures of patient outcomes will become increasingly important with the transition from volume-based to value-based care.

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.

[Stimulation of fracture healing by growth factors and cell-based technologies]

Bone has the special capability to completely regenerate after trauma and to re-establish its original geometry and biomechanical stability corresponding to the pretrauma conditions. Nevertheless, in daily clinical practice impaired fracture healing and nonunions are regular complications as a result of inadequate mechanical stability and/or insufficient biological processes around the fracture region. Since the beginning of the millennium, intensive research on the physiological processes in bone healing as well as the production and clinical administration of growth factors have enabled the possibility to improve the local biological processes during fracture healing by osteoinduction. Although the initial clinical results, particularly of bone morphogenetic proteins, in fracture healing were promising, growth factors did not become established for unrestricted use in the clinical application. Currently, additional growth factors are being investigated with respect to the potential supportive and osteoinductive characteristics for enhancement of fracture healing and possible clinical applications. Furthermore, the development of cell-based technologies is another promising approach to positively stimulate fracture healing. In addition to the gold standard of autologous bone grafting, harvesting of mesenchymal stroma cells by aspiration has gained in importance in recent years. Allogeneic bone cell transplantation procedures and in particular gene therapy are promising new strategies for the treatment of disorders of fracture healing. This review gives an overview of present and future possibilities for modulation of fracture healing by growth factors and cell-based technologies.

Tibiotalocalcaneal Arthrodesis Utilizing a Titanium Intramedullary Nail With an Internal Pseudoelastic Nitinol Compression Element: A Retrospective Case Series of 33 Patients

Nitinol has been shown to generate durable compression under loading via pseudoelastic shape memory. The purpose of this study was to evaluate the effectiveness of a hindfoot arthrodesis nail with an internal pseudoelastic nitinol compression element. Patients who had undergone tibiotalocalcaneal arthrodesis from 2013 to 2016 were identified at 2 tertiary referral centers (12-week follow-up minimum). Patients managed with a tibiotalocalcaneal nail with an internal nitinol compression element were identified for review. Sagittal computed tomographic scan reformats were reviewed to calculate a percentage of joint surface bony union. Intraoperative and postoperative radiographs were compared to calculate postoperative screw position change generated by the nitinol element, a surrogate for postoperative unloading of compressive forces. Thirty-three patients were included in analysis and 81% of patients had successful union of both tibiotalar and subtalar joints. Overall, 90% of all arthrodesis surfaces united. The union rate of arthrodesis surfaces among patients without Charcot osteoarthropathy was 94%. A history of Charcot was identified as a risk factor for subtalar nonunion (p = .04) and was associated with less complete computed tomography-based tibiotalar union: 94% versus 71% (p < .01). The posterior-to-anterior screw translated an average of 3.9 mm proximally relative to the rigid portion of the nail from intraoperative to initial postoperative radiographs (p < .0001). High rates of computed tomography-confirmed union were demonstrated in the face of challenging clinical scenarios. Shortening of the pseudoelastic nitinol element occurs early in the postoperative period, indicating continued unloading of the nitinol compression element through the arthrodesis sites after initial implantation.

Innovative Biomaterials for Bone Regrowth

The regenerative medicine, a new discipline that merges biological sciences and the fundamental of engineering to develop biological substitutes, has greatly benefited from recent advances in the material engineering and the role of stem cells in tissue regeneration. Regenerative medicine strategies, involving the combination of biomaterials/scaffolds, cells, and bioactive agents, have been of great interest especially for the repair of damaged bone and bone regrowth. In the last few years, the life expectancy of our population has progressively increased. Aging has highlighted the need for intervention on human bone with biocompatible materials that show high performance for the regeneration of the bone, efficiently and in a short time. In this review, the different aspects of tissue engineering applied to bone engineering were taken into consideration. The first part of this review introduces the bone cellular biology/molecular genetics. Data on biomaterials, stem cells, and specific growth factors for the bone regrowth are reported in this review.

Orthobiologics for Bone Healing

Orthobiologics are a group of biological materials and substrates that promote bone, ligament, muscle, and tendon healing. These substances include bone autograft, bone allograft, demineralized bone matrix, bone graft substitutes, bone marrow aspirate concentrate, platelet-rich plasma, bone morphogenetic proteins, platelet-derived growth factor, parathyroid hormone, and vitamin D and calcium. Properties of orthobiologics in bone healing include osteoconduction, osteoinduction, and osteogenesis. This article discusses the important properties of orthobiologics in bone healing, many of the orthobiologics currently available for bone healing, the related literature, their current clinical uses in sports medicine, and systemic factors that inhibit bone healing.

Comparison and Use of Allograft Bone Morphogenetic Protein Versus Other Materials in Ankle and Hindfoot Fusions

Bone grafting is a common procedure in foot and ankle surgery. Because autogenous graft use results in comorbidity to the patient, the search has been ongoing for the ideal substitute. A novel processing technique for allograft using bone marrow, which retains many of the growth factors, has shown promise in the spinal data and early reports of foot and ankle surgery. We performed a retrospective, comparative study of patients undergoing hindfoot and ankle arthrodesis, with a total of 68 patients included. Of the 68 patients, 29 (42.65%) received a bone morphogenetic protein allograft and 39 (57.35%) did not. The patient demographics and social and medical history were similar between the 2 groups and both groups had a similar time to union (p = .581). Of the 29 patients in the bone morphogenetic protein allograft group, 3 (10.3%) experienced nonunion and 4 (13.8%) developed a complication. Of the 39 patients undergoing other treatment, 7 (17.9%) experienced nonunion and 14 (35.9%) developed a complication. The difference for nonunion was not statistically significant (p = .5). However, the difference in the overall complication rate was statistically significant (p = .04). We found that this novel bone graft substitute is safe and can be used for foot and ankle arthrodesis.

Application of enamel matrix derivative and deproteinized bovine bone for the treatment of peri-implantitis after decontamination with an ultrasonic scaler: A case report

RATIONALE

The purpose of this report is to present a case of peri-implantitis with successful regeneration. The surface of the affected dental implant was decontaminated with an ultrasonic scaler and treated with bovine-derived hydroxyapatite and enamel matrix derivative.

PATIENT CONCERNS

A 52-year-old male was referred for evaluation of a dental implant placed in the mandibular right second premolar area.

DIAGNOSIS

The radiographic evaluation showed the loss of supporting bone around the dental implant. Bleeding upon probing and suppuration were observed, with the deepest probing depth at 6 mm.

INTERVENTIONS

The area was firstly treated with a nonsurgical approach. After re-evaluation, a full-thickness flap was elevated. The area was well debrided using various instruments, including curettes and an ultrasonic scaler. The defect area was grafted with bovine-derived hydroxyapatite and enamel matrix derivative.

OUTCOMES

Histopathologic evaluation revealed chronic inflammation with fibrosis and calcification. The evaluation at 2 years and 3 months after surgery showed that the prosthesis was functioning well. Bleeding upon probing and suppuration was not noted, and reduction of probing depth was seen, with the deepest depth at 4 mm. The area showed maintenance of graft material with increased radiopacity around the dental implant.

LESSONS

In conclusion, a case of peri-implantitis can be successfully treated with bovine-derived hydroxyapatite and enamel matrix derivative after surface decontamination with an ultrasonic scaler.

Bone regeneration strategies: Engineered scaffolds, bioactive molecules and stem cells current stage and future perspectives

Bone fractures are the most common traumatic injuries in humans. The repair of bone fractures is a regenerative process that recapitulates many of the biological events of embryonic skeletal development. Most of the time it leads to successful healing and the recovery of the damaged bone. Unfortunately, about 5-10% of fractures will lead to delayed healing or non-union, more so in the case of co-morbidities such as diabetes. In this article, we review the different strategies to heal bone defects using synthetic bone graft substitutes, biologically active substances and stem cells. The majority of currently available reviews focus on strategies that are still at the early stages of development and use mostly in vitro experiments with cell lines or stem cells. Here, we focus on what is already implemented in the clinics, what is currently in clinical trials, and what has been tested in animal models. Treatment approaches can be classified in three major categories: i) synthetic bone graft substitutes (BGS) whose architecture and surface can be optimized; ii) BGS combined with bioactive molecules such as growth factors, peptides or small molecules targeting bone precursor cells, bone formation and metabolism; iii) cell-based strategies with progenitor cells combined or not with active molecules that can be injected or seeded on BGS for improved delivery. We review the major types of adult stromal cells (bone marrow, adipose and periosteum derived) that have been used and compare their properties. Finally, we discuss the remaining challenges that need to be addressed to significantly improve the healing of bone defects.

The role of biologic in foot and ankle trauma-a review of the literature

PURPOSE OF REVIEW

The use of biologics in orthopedics is becoming increasingly popular as an adjuvant in healing musculoskeletal injuries. Though many biologics involved in the management of foot and ankle injuries are used based on physician preference, reports of improved outcomes when combined with standard operative treatment has led to further clinical interest especially in foot and ankle trauma.

RECENT FINDINGS

The most recent studies have shown benefits for biologic use in patients predisposed to poor bone and soft tissue healing. Biologics have shown benefit in treating soft tissue injuries such as Achilles ruptures as well as the complications of trauma such as non-unions and osteoarthritis. Biologics have shown some benefit in improving functional and pain scores, as well as reducing time to heal in foot and ankle traumatic injuries, with particular success shown with patients that have risk factors for poor healing. As the use of biologics continues to increase, there is a need for high-level studies to confirm early findings of lower level reports.

Living Cryopreserved Bone Allograft as an Adjunct for Hindfoot Arthrodesis

Hindfoot arthrodesis is a frequently performed procedure by foot and ankle surgeons. The relatively high nonunion rate associated with these procedures has led surgeons to use adjunctive bone graft to help augment osseous union. Cellular bone allografts are a specific type of graft that incorporates osteoconductive, osteoinductive, and osteogenic properties while also eliminating the common disadvantages of autografts and traditional allografts. This article discusses the role of cellular bone allografts in hindfoot arthrodesis procedures, a review of current literature, and a comparison of available products.

Degradation of extracellular matrix regulates osteoblast migration: A microfluidic-based study

Bone regeneration is strongly dependent on the capacity of cells to move in a 3D microenvironment, where a large cascade of signals is activated. To improve the understanding of this complex process and to advance in the knowledge of the role of each specific signal, it is fundamental to analyze the impact of each factor independently. Microfluidic-based cell culture is an appropriate technology to achieve this objective, because it allows recreating realistic 3D local microenvironments by taking into account the extracellular matrix, cells and chemical gradients in an independent or combined scenario. The main aim of this work is to analyze the impact of extracellular matrix properties and growth factor gradients on 3D osteoblast movement, as well as the role of cell matrix degradation. For that, we used collagen-based hydrogels, with and without crosslinkers, under different chemical gradients, and eventually inhibiting metalloproteinases to tweak matrix degradation. We found that osteoblast's 3D migratory patterns were affected by the hydrogel properties and the PDGF-BB gradient, although the strongest regulatory factor was determined by the ability of cells to remodel the matrix.

Emerging Concepts in Treating Cartilage, Osteochondral Defects, and Osteoarthritis of the Knee and Ankle

The management and treatment of cartilage lesions, osteochondral defects, and osteoarthritis remain a challenge in orthopedics. Moreover, these entities have different behaviors in different joints, such as the knee and the ankle, which have inherent differences in function, biology, and biomechanics. There has been a huge development on the conservative treatment (new technologies including orthobiologics) as well as on the surgical approach. Some surgical development upraises from technical improvements including advanced arthroscopic techniques but also from increased knowledge arriving from basic science research and tissue engineering and regenerative medicine approaches. This work addresses the state of the art concerning basic science comparing the knee and ankle as well as current options for treatment. Furthermore, the most promising research developments promising new options for the future are discussed.

Bone Marrow Aspirate Concentrate and Its Uses in the Foot and Ankle

Bone marrow aspirate has been used for the adjunctive treatment of numerous pathologic conditions in orthopedics. Viable cells are found in aspiration from many different anatomic regions of the body. Concentration of these cells has been shown to improve healing due to the increased number of certain important cells. This article discusses the mechanisms involved and reviews the literature.

Allograft Bone: What Is the Role of Platelet-Derived Growth Factor in Hindfoot and Ankle Fusions

Arthrodesis of the ankle or foot is a common procedure for chronic pain and disability. Nonunion remains a prevalent complication among arthrodesis procedures. Some patients present with an inherent risk of developing a nonunion. Allograft biologics have gained popularity in an effort to reduce complications such as nonunion. Various biologics bring unique properties while maintaining a singular purpose. Platelet-derived growth factor (PDGF) may be introduced into a fusion site to facilitate healthy bony consolidation. The purpose of this article is to review the benefits and modalities of PDGF and how it can improve patient outcomes in ankle and hindfoot fusions.

Comparison of Posterior Approach With Intramedullary Nailing Versus Lateral Transfibular Approach With Fixed-Angle Plating for Tibiotalocalcaneal Arthrodesis

BACKGROUND

A variety of operative approaches and fixation techniques have been described for tibiotalocalcaneal (TTC) arthrodesis. The intramedullary (IM) nail and lateral, fixed-angle plating are commonly used because of ease of use and favorable biomechanical properties. A lateral, transfibular (LTF) approach allows for direct access to the tibiotalar and subtalar joints, but the posterior, Achilles tendon-splitting (PATS) approach offers a robust soft tissue envelope. The purpose of this study was to compare the results of TTC arthrodesis with either a PATS approach with IM nailing or LTF approach with fixed-angle plating.

METHODS

A retrospective review was performed on all patients who underwent simultaneous TTC arthrodesis with minimum 1 year clinical and radiographic follow up. Patients were excluded if they underwent TTC arthrodesis through an approach other than PATS or LTF, and received fixation without an IM nail or fixed-angle plate. Primary outcomes examined were union rate, revisions, and complications. Thirty-eight patients underwent TTC arthrodesis with a PATS approach and IM nailing, and 28 with a LTF approach and lateral plating.

RESULTS

The overall union rate was 71%; 76% (29 of 38 patients) for the PATS/IM nail group, and 64% (18 of 28) for LTF/plating group ( P = .41). Symptomatic nonunion requiring revision arthrodesis occurred in 16% (6 of 38) of the PATS/IM nail group versus 7% (2 of 28) in the LTF/lateral plating group ( P = .45). There were no significant differences in individual tibiotalar or subtalar union rates, superficial wound problems, infection, symptomatic hardware, stress fractures, or nerve irritations.

CONCLUSION

Union, revision, and complication rates were similar for TTC arthrodesis performed with a PATS approach and IM nail compared with an LTF approach and fixed-angle plate in a complex patient population. Both techniques were adequate, especially when prior incisions, preexisting hardware, or deformity preclude options.

LEVEL OF EVIDENCE

Level III, retrospective comparative study.

* Roughness and Hydrophilicity as Osteogenic Biomimetic Surface Properties

Successful dental and orthopedic implant outcomes are determined by the degree of osseointegration. Over the last 60 years, endosseous implants have evolved to stimulate osteogenesis without the need for exogenous biologics such as bone morphogenetic proteins. An understanding of the interaction between cells and the physical characteristics of their environments has led to development of bioactive implants. Implant surfaces that mimic the inherent chemistry, topography, and wettability of native bone have shown to provide cells in the osteoblast lineage with the structural cues to promote tissue regeneration and net new bone formation. Studies show that attachment, proliferation, differentiation, and local factor production are sensitive to these implant surface characteristics. This review focuses on how surface properties, including chemistry, topography, and hydrophilicity, modulate protein adsorption, cell behavior, biological reactions, and signaling pathways in peri-implant bone tissue, allowing the development of true biomimetics that promote osseointegration by providing an environment suitable for osteogenesis.

Stem cell-derived exosomes: A promising strategy for fracture healing

OBJECTIVES

To describe the biological characteristics of exosomes and to summarize the current status of stem cell-derived exosomes on fracture healing. Meanwhile, future challenges, limitations and perspectives are also discussed.

METHODS

Search and analyze the related articles in pubmed database through the multi-combination of keywords like "stem cells","exosomes","bone regeneration" and "fracture healing".

CONCLUSION

Stem cell-derived exosome therapy for fracture healing has been enjoying popularity and is drawing increasing attention. This strategy helps to promote proliferation and migration of cells, as well as osteogenesis and angiogenesis, in the process of bone formation. Although the exact mechanisms remain elusive, exosomal miRNAs seem to play vital roles. Future studies are required to solve multiple problems before clinical application, including comprehensive and thorough understanding of exosomes, the exact roles of exosomes in regulating bone formation, and the optimal source, dose and frequency of treatment, as well as technical and safety issues. Moreover, studies based on fracture models of large animals are could offer guidance and are in demand.

Osseous Healing in Foot and Ankle Surgery with Autograft, Allograft, and Other Orthobiologics

In the surgical treatment of foot and ankle abnormality, many problems require bone grafting for successful osseous union. Nonunion, reconstruction, and arthrodesis procedures pose specific challenges due to bony defects secondary to trauma, malunions, or previous surgery. Nonunion in foot and ankle arthrodesis is a significant risk and is well documented in recent literature. This article is a review of the recent literature regarding the use of bone graft and orthobiologics in foot and ankle surgery.

Current Orthobiologics for Elective Arthrodesis and Nonunions of the Foot and Ankle

A fusion rate of 100% would be ideal. Despite adhering to sound surgical principles, complete compliance, and no adverse comorbidities, that 100% fusion rate goal is elusive. Orthobiologics are a special class of materials developed to enhance the fusion rates in foot and ankle arthrodesis sites. Whether orthobiologics are used for the first fusion or reserved for a nonunion is debatable, especially when considering cost.

Bone fracture healing in mechanobiological modeling: A review of principles and methods

Bone fracture is a very common body injury. The healing process is physiologically complex, involving both biological and mechanical aspects. Following a fracture, cell migration, cell/tissue differentiation, tissue synthesis, and cytokine and growth factor release occur, regulated by the mechanical environment. Over the past decade, bone healing simulation and modeling has been employed to understand its details and mechanisms, to investigate specific clinical questions, and to design healing strategies. The goal of this effort is to review the history and the most recent work in bone healing simulations with an emphasis on both biological and mechanical properties. Therefore, we provide a brief review of the biology of bone fracture repair, followed by an outline of the key growth factors and mechanical factors influencing it. We then compare different methodologies of bone healing simulation, including conceptual modeling (qualitative modeling of bone healing to understand the general mechanisms), biological modeling (considering only the biological factors and processes), and mechanobiological modeling (considering both biological aspects and mechanical environment). Finally we evaluate different components and clinical applications of bone healing simulation such as mechanical stimuli, phases of bone healing, and angiogenesis.

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

BACKGROUND

Bone graft substitutes are often required in patients at risk for nonunion, and therefore, an allograft that most closely mimics an autograft is highly sought after. This study explored the utility and efficacy of a cellular bone allograft used for foot and ankle arthrodesis and revision nonunion procedures in a patient population at risk for nonunion.

METHODS

An institutional review board-approved retrospective review of consecutive patients who underwent arthrodesis and revision nonunion procedures with a cellular bone allograft was performed at a single academic institution. No external sources of funding were provided for this study. Inclusion criteria included patients who were more than 1 year after surgery or less than 1 year after surgery if they had undergone a second operative procedure for nonunion or if they had computed tomography-documented union. Forty operative procedures in 36 patients with a mean follow-up of 13 months (range, 6-25 months) were included for data analysis. All patients had at least one of the following risk factors associated with nonunion: current smoker, diabetes, avascular necrosis (AVN) of the involved bone, active same-site operative infection, history of nonunion, previous same-site surgery, or gap of 5 mm or greater after joint preparation. The primary outcome was radiographic union.

RESULTS

The union rate in this high-risk population was 83% (33/40). Univariate analysis demonstrated that the use of a cellular bone allograft helped mitigate the presence of risk factors known to cause nonunion. There was no significant difference in fusion rates among groups with current smoking, AVN of the involved bone, active same-site operative infections, history of nonunion, rheumatoid arthritis on medication, previous same-site operative procedures or infections, or a gap of 5 mm or greater after joint preparation. However, in this population, diabetic and female patients remained at a high risk of recurrent nonunion ( P = .0015), despite the use of a cellular bone allograft. Chi-square analysis of patients with increasing numbers of risk factors directly correlated with an increased risk of nonunion ( P = .025). Four wound complications were reported in this cohort that required irrigation and debridement (10%).

CONCLUSION

These data demonstrated a union rate of 83% in patients with risk factors known to cause nonunion. The benefits of the use of a cellular bone allograft allowed for the avoidance of morbidity associated with autograft harvesting while still improving the local biology to facilitate fusion in a difficult patient population to attain a successful fusion mass.

LEVEL OF EVIDENCE

Level IV, retrospective case series.

Recombinant human platelet-derived growth factor-BB versus autologous bone graft in foot and ankle fusion: A systematic review and meta-analysis

Today, autogenous bone graft (ABG) is still considered as the gold standard for joint fusion. Recombinant human platelet-derived growth factor-BB (rhPDGF-BB) which is of chemotactic and mitogenic to mesenchymal stem cells and possesses outstanding osteogenetic potentials has been used for ankle and foot fusion in recent years. The goal of this article is to evaluate the safety and efficacy of rhPDGF-BB versus ABG in foot and ankle fusion. The PubMed MEDLINE, EMBASE, Web of Science, and Cochrane Library were systematic searched. Finally, three randomized controlled trials (RCTs) with 634 patients were enrolled in this study. Results of radiologic effectiveness which included CT and radiographic union rates revealed that there was no significant difference between rhPDGF-BB approach and ABG approach. Analysis of clinical results held the same outcomes expect that ABG group was superior in long-term Short Form-12 physical component scores. The pooled results also demonstrated that rhPDGF-BB was as safe as ABG in foot and ankle surgery. However, autograft harvesting procedure has some drawbacks such as donor-site pain and morbidity, additional operation time, blood loss, and scarring, which can be overcome by rhPDGF-BB. Thus, rhPDGF-BB is a viable alternative to autograft in foot and ankle fusion surgery. Yet, more high-quality RCTs with long-term follow-up are still required to make the final conclusion.

Clinical Outcomes of Nonunions of Hindfoot and Ankle Fusions

BACKGROUND

While nonunion after foot and ankle fusion surgery has been associated with poor outcomes, we are not aware of any longitudinal study on this subject. Thus, we prospectively evaluated the impact of nonunion on clinical outcomes of foot and ankle fusions and identified potential risk factors for nonunion after these procedures.

METHODS

Using data from a randomized clinical trial on recombinant human platelet-derived growth factor-BB (rhPDGF-BB; Augment Bone Graft, BioMimetic Therapeutics), union was defined either by assessment of computed tomography (CT) scans at 24 weeks by a reviewer blinded to the type of treatment or by the surgeon's composite assessment of clinical and radiographic findings at 52 weeks and CT findings at 24 or 36 weeks. The nonunion and union groups (defined with each assessment) were then compared in terms of clinical outcome scores on the American Orthopaedic Foot & Ankle Society Ankle-Hindfoot Scale (AOFAS-AHS), Foot Function Index (FFI), and Short Form-12 (SF-12) as well as age, sex, body mass index (BMI), smoking status, diabetes status, work status, and arthrodesis site.

RESULTS

Blinded CT assessment identified nonunion in 67 (18%) of 370 patients, and surgeon assessment found nonunion in 21 (5%) of 389 patients. Postoperatively, the nonunion group scored worse than the union group, regardless of the method used to define the nonunion, on the AOFAS-AHS and FFI, with mean differences of 10 and 12 points, respectively, when nonunion was determined by blinded CT assessment and 19 and 20 points when it was assessed by the surgeon. The nonunion group also had worse SF-12 Physical Component Summary scores. Differences between the union and nonunion groups were clinically meaningful for all outcome measures, regardless of the nonunion assessment method. The concept of an asymptomatic nonunion (i.e., imaging indicating nonunion but the patient doing well) was not supported. Patients with nonunion were more likely to be overweight, smokers, and not working.

CONCLUSIONS

This prospective longitudinal study demonstrated poorer functional outcomes in patients with a nonunion after foot and ankle fusion, regardless of whether the diagnosis of nonunion was based on CT only or on combined clinical, radiographic, and CT assessment.

LEVEL OF EVIDENCE

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

Injectable Recombinant Human Platelet-derived Growth Factor in Collagen Carrier for Hindfoot Fusion

Arthrodesis of the hindfoot is a common procedure for degenerative joint disease and/or severe deformity. Nonunion is a common complication from this procedure, causing an increased burden to the patient and health care system, often resulting in the need for revision surgery. Recombinant human platelet-derived growth factor (rhPDGF) has been shown to be a safe and effective tool to enhance arthrodesis rates in hindfoot surgery while avoiding the potential morbidity of bone grafting. This article provides a review of the role of rhPDGF in hindfoot fusions, and the surgical technique for performing an rhPDGF enhanced double-arthrodesis through a medial approach.

The Efficacy of Platelet-Derived Growth Factor as a Bone-Stimulating Agent

Nonunion remains the most impactful complication following ankle and hindfoot arthrodesis. Historically, surgeons have relied on autologous bone graft (ABG) to combat nonunion risk. Although effective, ABG remains limited in quantity, varies in quality, and can be associated with harvest site pain and morbidity. Use of alternative bone-stimulating agents, however, avoids harvesting an autograft, and provides a more predictable dose-response efficacy. This article highlights findings from basic science, animal, and human clinical research that led to the approval of Augment Bone Graft. We present an adaptation of the surgical techniques described for investigators participating in the pivotal trial.

The Use of Allostem in Subtalar Fusions

Subtalar arthrodesis is the mainstay for treatment of a variety of hindfoot problems associated with arthritis, however with an unpredictable if not high rate of nonunion. This article covers the use of adipose-derived stem cells as an adjunct or alternative to autologous or other bone grafting materials. Promising development and encouraging data exist with respect to the use of adipose-derived mesenchymal stem cells for bone arthrodesis, which is discussed in more detail in the article.

Efficacy of a Cellular Allogeneic Bone Graft in Foot and Ankle Arthrodesis Procedures

A cellular allogeneic bone graft can be used in patients at high risk for nonunion after arthrodesis surgery. This study explores the utility and efficacy of MAP3 in foot and ankle arthrodesis procedures. Map3 is a cellular allogeneic bone graft that contains osteogenic, osteoconductive, osteoinductive, and angiogenic properties. A total of 23 mostly high-risk patients were included in this study. The overall fusion rate was 83%. Univariate analysis demonstrated diabetic patients remain at risk of recurrent nonunion (P<.001) despite supplementation with MAP3. These data demonstrate successful fusion in high-risk patients when MAP3 is used.

The Role of Orthobiologics in Fracture Healing and Arthrodesis

Nonunion after tibial shaft fracture and hindfoot arthrodesis remains a major problem. Known risk factors include advanced age, immunosuppression, smoking, and diabetes. Several factors must be considered in the fracture healing process. This review evaluates the efficacy of orthobiologics in improving union rates after fracture or arthrodesis. Use of compounds have shown increased cellular proliferation experimentally. Percutaneous autologous bone marrow has shown increased cellular proliferation. Matrix supplementation has shown significant improvements in bone healing. Several studies have highlighted the importance of adequate graft fill over graft type. Patients at increased risk for nonunion would benefit most from these adjuvant therapies.

Bone Marrow Aspirate Concentrate for Bone Healing in Foot and Ankle Surgery

Autologous bone marrow aspirate concentrate (BMAC) has become a popular orthobiologic to augment bone healing. The potential benefit comes from osteoprogenitor cells and growth factors that can lead to new bone formation in the setting of foot and ankle arthrodesis procedures. BMAC has an excellent safety record and has demonstrated efficacy in animal models of bone healing. Although scant, the literature on the use of BMAC in foot and ankle surgery does demonstrate promise for this orthobiologic adjuvant.

Vancouver Experience of Recombinant Human Platelet-Derived Growth Factor

Joint arthrodesis utilizing autogenous bone graft remains the gold standard of treatment in fusion procedures of the foot and ankle. Graft harvest, however, has been associated with increased morbidity to patients as well as increased costs. With this in mind, multiple clinical studies have evaluated the efficacy of recombinant human platelet-derived growth factor (rh-PDGF-BB) with beta-tricalcium phosphate (B-TCP) to augment in foot and ankle arthrodesis with favorable results. These factors have led to the increased use of rh-PDGF-BB with B-TCP in Vancouver with good clinical results.

Bone healing in 2016

Delayed fracture healing and nonunion occurs in up to 5-10% of all fractures, and can present a challenging clinical scenario for the treating physician. Methods for the enhancement of skeletal repair may benefit patients that are at risk of, or have experienced, delayed healing or nonunion. These methods can be categorized into either physical stimulation therapies or biological therapies. Physical stimulation therapies include electrical stimulation, low-intensity pulsed ultrasonography, or extracorporeal shock wave therapy. Biological therapies can be further classified into local or systemic therapy based on the method of delivery. Local methods include autologous bone marrow, autologous bone graft, fibroblast growth factor-2, platelet-rich plasma, platelet-derived growth factor, and bone morphogenetic proteins. Systemic therapies include parathyroid hormone and bisphosphonates. This article reviews the current applications and supporting evidence for the use of these therapies in the enhancement of fracture healing.

The Importance of Sufficient Graft Material in Achieving Foot or Ankle Fusion

BACKGROUND

Nonunion, an important complication following foot and ankle arthrodesis, causes substantial morbidity and disability. In patients undergoing hindfoot and ankle arthrodesis, autogenous bone graft (autograft) or a suitable alternative is often used to promote osseous fusion across the joint. This study assessed the importance of adequate graft material in the fusion space to achieve joint fusion during ankle and hindfoot arthrodesis.

METHODS

This study used data from a previously published clinical trial of grafting material (recombinant human platelet-derived growth factor-BB with beta-tricalcium phosphate [rhPDGF-BB/β-TCP] or autograft) for healing in hindfoot and ankle arthrodesis to correlate the amount of graft fill at 9 weeks with ultimate healing. Patients who received supplemental graft material for ankle or hindfoot arthrodesis for end-stage ankle or hindfoot arthritis were stratified according to nonunion risk factors and surgical fusion site. Patients underwent arthrodesis using standard rigid internal fixation. Graft fill was defined as "adequate" if the material occupied ≥50% of the cross-sectional area of the fusion space on a computed tomography (CT) scan made at 9 weeks. Fusion was defined as osseous bridging of ≥50% of each articulation on a CT scan made at 24 weeks. Three hundred and seventy-nine patients with 573 joints (383 managed with rhPDGF-BB/β-TCP and 190 managed with autograft) that underwent arthrodesis had complete follow-up with 9-week and 24-week CT scans available.

RESULTS

Overall, 472 (82%) of 573 joints had adequate graft fill; of those, 383 (81%) were successfully fused at 24 weeks compared with 21 (21%) of 101 joints without adequate graft fill (p < 0.0001). Absolute fusion rate differences (joints with adequate fill minus those without adequate fill) were consistent across joints (61% to 63%) and for graft materials. The overall odds ratio (OR) of successful fusion in joints with adequate graft fill compared with those without adequate graft fill was 16.4 (95% confidence interval, 9.6 to 27.9).

CONCLUSIONS

This study demonstrates an association between the amount of graft material and successful hindfoot and ankle arthrodesis. Graft material filling of ≥50% of the fusion space at 9 weeks, regardless of type or origin, was associated with significantly higher fusion rates at 24 weeks.

LEVEL OF EVIDENCE

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

Total Hip Arthroplasty in 6690 Patients with Inflammatory Arthritis: Effect of Medical Comorbidities and Age on Early Mortality

Objective.

We analyzed early mortality after total hip arthroplasty (THA) in patients with inflammatory arthritis (IA), adjusting for medical comorbidities and socioeconomic background.

Methods.

Data on 6690 patients with IA who underwent THA during 1992–2012 were extracted from the Swedish Hip Arthroplasty Register. Data on comorbidity, measured using the Charlson Comorbidity Index (CCI), and socioeconomic data were gathered from the Swedish National Inpatient Register and Statistics Sweden. The CCI was divided into low (0), moderate (1–2), and high (> 2). Cox proportional hazards models were fitted to calculate adjusted HR of early mortality, with 95% CI.

Results.

Twenty-five patients (0.4%) died within 0–90 days, giving a 90-day unadjusted survival rate of 99.6% (CI 99.5–99.8). Comorbidity was associated with an increased risk of death within 90 days postoperatively [high vs low CCI: adjusted HR 9.0 (CI 1.6–49.9)]. There was a trend toward lower risk of death during the period 1999–2005, although patients operated on during this period had more comorbidities than those operated on from 1992 to 1998. A large proportion of patients was re-admitted to hospital within 90 days after the index procedure (30.2%), but rarely for cardiovascular reasons.

Conclusion.

Medical comorbidity and an age above 75 years are associated with a substantial increase in the risk of early death after THA in patients with IA. Awareness of potential risk factors may alert clinicians and thus improve perioperative care.

A study to evaluate the safety of platelet-derived growth factor for treatment of osteochondral defects of the talus

PURPOSE

An arthroscopic procedure for the treatment of osteochondral defects using platelet-derived growth factor (PDGF) carried out in a matrix of tricalcium phosphate was developed. This prospective, case-series-based study was designed to evaluate the safety and clinical utility of this procedure.

METHODS

Patients with an isolated osteochondral defect larger than 5 mm long, 3 mm wide, and 5 mm deep and smaller than 30 mm long, 25 mm wide, or 20 mm deep were considered for enrolment. Only patients with chronic lesions were enroled. Arthroscopic debridement was followed by the placement of recombinant human PDGF in a matrix of tricalcium phosphate. The Ankle Osteoarthritis Scale (AOS), visual analogue scale (VAS) for pain, and SF-36 questionnaires were administered at 0, 2, 6, 12, and 24 weeks. Magnetic resonance imaging (MRI) and computed tomography (CT) scans were taken before and after surgery.

RESULTS

Five patients were ultimately enroled in this proof-of-concept trial. All outcome measures demonstrated marked improvement from baseline to final follow-up: The mean weight bearing VAS pain score improved by 49%, and the mean AOS functional score improved by 28%. Bone healing was seen on CT, and reduction in oedema signal was seen on MRI.

CONCLUSION

This new procedure may offer a promising alternative for the treatment of osteochondral defects. Further high-quality studies are needed to confirm these results and to analyse the long-term effects of the procedure. The clinical relevance of this study is that the procedure may provide a less invasive option with improved bone healing compared to standard techniques .

LEVEL OF EVIDENCE

IV.

Extracellular signaling molecules to promote fracture healing and bone regeneration

To date, the delivery of signaling molecules for bone regeneration has focused primarily on factors that directly affect the bone formation pathways (osteoinduction) or that serve to increase the number of bone forming progenitor cells. The first commercialized growth factors approved for bone regeneration, Bone Morphogenetic Protein 2 and 7 (BMP2 and BMP7), are direct inducers of osteoblast differentiation. As well, newer generations of potential therapeutics that target the Wnt signaling pathway are also direct osteoinducers. On the other hand, some signaling molecules may play a role as mitogens and serve to increase the number of bone producing cells or may increase vascularization. This is true for factors such as Platelet Derived Growth Factor (PDGF) or Fibroblast Growth Factor (FGF). Vascular Endothelial Growth Factor (VEGF) likely has a special role. Not only does it induce new blood vessel formation, it also has direct effects on osteoblasts through endothelial cell-based BMP production. In addition to these pathways that classically have targeted bone production, there are also opportunities to target other aspects of the bone healing process such as inflammation, vascularization, and cell ingress to the fracture site. Bone regeneration is highly complex with defined, yet overlapping stages of healing. We will review established and novel extracellular signaling factors associated with various stages of fracture healing that could be targeted to promote enhanced bone regeneration. Importantly, multiple potential cell and tissues could be targeted to enhance healing in addition to focusing solely on osteoinductive therapeutics.

Prospective, Multicenter Evaluation of Allogeneic Bone Matrix Containing Viable Osteogenic Cells in Foot and/or Ankle Arthrodesis

BACKGROUND

Cellular bone allograft (CBA) possesses osteogenic, osteoinductive, and osteoconductive elements essential for bone healing. The purpose of this study was to assess the safety and effectiveness of CBA in foot and/or ankle arthrodeses.

METHODS

A prospective, multicenter, open-label clinical trial using CBA was performed. At 6 weeks and at 3, 6, and 12 months, imaging was performed and the subject's pain, function, and quality of life (QOL) status (Visual Analog Scale, American Orthopaedic Foot & Ankle Society Hindfoot Scale, and the Short Form 36) were recorded. The per protocol population consisted of 92 patients at 6 months and 76 patients at 12 months, with 153 and 129 total arthrodeses, respectively.

RESULTS

At 6 months, fusion rates were 68.5% for all patients and 81.1% for all joints; at 12 months, rates were 71.1% and 86.8%, respectively. Certain high-risk subjects (eg, with diabetes or obesity) had fusion rates comparable to those of normal patients. Statistically significant improvements in pain, function, and QOL were observed, and fusion correlated with both function and QOL outcomes at 6 and 12 months. There were no adverse events attributable to CBA.

CONCLUSION

Fusion rates using CBA were higher than or comparable to fusion rates with autograft that have been reported in the recent literature, and CBA fusion rates were not adversely affected by several high-risk patient factors. CBA was a safe and effective graft material to achieve fusion in patients with compromised bone healing and may provide an effective autograft replacement for foot and/or ankle arthrodeses.

LEVEL OF EVIDENCE

Level II, prospective study.

A new method for achieving compression in hindfoot arthrodesis

BACKGROUND

When performing hindfoot arthodeses, one goal of fixation is often to achieve compression across the joint. Traditional lag screws are applied eccentrically, providing compression more on the edge of the fusion. A new technique, using a post in one bone and a lag screw through the post to the other bone, may offer better compression across more of the joint.

METHODS

There are three parts to this study comparing a post-and-screw construct to traditional lag screws. Synthetic bone models, representative of the talonavicular joint, were created and assessed for biomechanical measures of compression. Next, the post-and-screw construct was tested in cadavers, under conditions representing early weight bearing after arthrodesis surgery. Finally, 18 patients who had a talonavicular fusion with a post-and-screw construct with one surgeon were compared to the previous 18 patients fixed with traditional screws.

RESULTS

In the synthetic bone model, the post-and-screw construct brought the centre of compression closer to the centre of the joint, suggesting compression was less eccentric. Neither traditional screws nor the post-and-screw construct were sufficiently strong to resist early weight bearing forces in cadaver specimens. In the clinical comparison, four patients had a painful nonunion when fixed with traditional screws, compared to none in the post-and-screw construct.

CONCLUSIONS

A post-and-screw construct spreads the forces of compression more uniformly across an arthrodesis, even when placed eccentrically. Although not all the biomechanical measures were superior, the post-and-screw construct achieved higher levels of successful fusion in patients. This technology may offer improved outcomes in some clinical scenarios and deserves further study.

LEVEL OF EVIDENCE

Level 3.

Prospective Randomized Controlled Trial of Hindfoot and Ankle Fusions Treated With rhPDGF-BB in Combination With a β-TCP-Collagen Matrix

BACKGROUND

Ankle and hindfoot arthrodesis is often supplemented with autograft to promote bony union. Autograft harvest can lead to increased perioperative morbidity. Purified recombinant human platelet-derived growth factor BB homodimer (rhPDGF-BB) has stimulated bone formation in mandibular defects and hindfoot fusion. This randomized controlled trial evaluated the efficacy and safety of rhPDGF-BB combined with an injectable, osteoconductive beta-tricalcium phosphate (β-TCP)-collagen matrix versus autograft in ankle and hindfoot fusions.

METHODS

Seventy-five patients requiring ankle or hindfoot fusion were randomized 5:1 for rhPDGF-BB/β-TCP-collagen (treatment, n = 63) or autograft (control, n = 12). Prospective analysis included 142 autograft control subjects from another clinical trial with identical study protocols. Standardized operative and postoperative protocols were used. Patients underwent standard internal fixation augmented with autograft or 0.3 mg/mL rhPDGF-BB/β-TCP-collagen. Radiologic, clinical, and quality-of-life outcomes were assessed over 52 weeks. Primary outcome was joint fusion (50% or more osseous bridging on computed tomography) at 24 weeks. Secondary outcomes included radiographs, clinical healing status, visual analog scale pain score, American Orthopaedic Foot & Ankle Society Ankle-Hindfoot Scale score, Foot Function Index score, and Short Form-12 score. Noninferiority P values were calculated.

RESULTS

Complete fusion of all involved joints at 24 weeks as indicated by computed tomography was achieved in 53 of 63 (84%) rhPDGF-BB/β-TCP-collagen-treated patients and 100 of 154 (65%) autograft-treated patients (P < .001). Mean time to fusion was 14.3 ± 8.9 weeks for rhPDGF-BB/β-TCP-collagen patients versus 19.7 ± 11.5 weeks for autograft patients (P < .01). Clinical success at 52 weeks was achieved in 57 of 63 (91%) rhPDGF-BB/β-TCP-collagen patients and 120 of 154 (78%) autograft patients (P < .001). Safety-related outcomes were equivalent. Autograft controls had 2 bone graft harvest infections.

CONCLUSIONS

Application of rhPDGF-BB/β-TCP-collagen was a safe, effective alternative to autograft for ankle and hindfoot fusions, eliminating the pain and morbidity associated with autograft harvesting.

LEVEL OF EVIDENCE

Level I, prospective randomized study.