Use of bone morphogenetic proteins in arthrodesis: clinical results

Neglected pelvic fragility fracture managed with unilateral triangular osteosynthesis

We report on the treatment of a neglected displaced vertical shear pelvic fracture with functional impairment 6 months after injury in a 74-year-old woman with underlying osteoporosis. She was managed with open reduction and internal fixation and grafting of her left SI joint, while the ipsilateral pubic rami fractures were treated conservatively. She achieved union and pain free weight bearing 6 months postoperatively. Appropriate evaluation of the pathology and selection of the appropriate treatment in this elderly patient cohort is essential for a successful outcome. Experienced surgical team and individualized treatment approach are also vital to optimize the result of treatment.

Hip fractures in the young polytrauma patient: a review and the latest data from the UK

Managing a hip fracture in a young adult patient in the setting of polytrauma is a particularly challenging prospect. In the UK between 2018 and 2020, 11,969 patients were recorded in the Trauma Audit and Research Network as a patient with polytrauma. Of these patients, 611 (5.1%) had a hip fracture. In this article, we discuss the initial assessment and management of these patients and common problems that are encountered and how the evidence available can help guide management.

Pelvic Girdle Pain, Hypermobility Spectrum Disorder and Hypermobility-Type Ehlers-Danlos Syndrome: A Narrative Literature Review

Pelvic girdle pain (PGP) refers specifically to musculoskeletal pain localised to the pelvic ring and can be present at its anterior and/or posterior aspects. Causes such as trauma, infection and pregnancy have been well-established, while patients with hypermobile joints are at greater risk of developing PGP. Research exploring this association is limited and of varying quality. In the present study we report on the incidence, pathophysiology, diagnostic and treatment modalities for PGP in patients suffering from Hypermobility Spectrum Disorder (HSD) and Hypermobility-Type Ehlers-Danlos Syndrome (hEDS). Recommendations are made for clinical practice by elaborating on screening, diagnosis and management of such patients to provide a holistic approach to their care. It appears that this cohort of patients are at greater risk particularly of mental health issues. Moreover over, they may require a multidisciplinary approach for their management. Ongoing research is still required to expand our understanding of the relationship between PGP, HSD and hEDS by appropriately diagnosing patients using the latest updated terminologies and by conducting randomised control trials to compare outcomes of interventions using standardised patient reported outcome measures.

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.

Bone morphogenic protein-2 use in revision total hip arthroplasty with acetabular defects

INTRODUCTION

The restoration of acetabular bone stock during revision hip arthroplasty remains a challenge. There have been no clinical series reporting the efficacy of bone morphogenic protein-2 (rhBMP-2) in the revision hip setting.

METHODS

We retrospectively reviewed the radiographs and records of 15 patients who received rhBMP-2 mixed with allograft bone chips (+BMP), and 14 who received allograft bone chips alone (-BMP) for their acetabular defect during revision total hip arthroplasty with a mean two-year follow up. Radiographs were evaluated for acetabular defect size, superior cup migration, and changes in the lateral cup abduction angle. Modified Harris hip scores were used for evaluation of clinical outcomes.

RESULTS

Patients in the +BMP group compared to the -BMP group had significantly larger amounts of cancellous bone chips used (72.1 ± 35.5 cc vs. 38.6 ± 14.1 cc; p = 0.003). Mean rhBMP-2 used per case was 7.4 ± 3.1 mg in the +BMP group. Three patients in the -BMP group had cup migration which was not observed in the +BMP group. Mean Harris hip scores (HHS) improved post-operatively in both groups (40.1 ± 20.9 to 71.9 ± 19, p < .0001). No local adverse reaction was noted in the +BMP group.

CONCLUSION

rhBMP-2 had modest clinical benefit in the setting of revision THA. Cost of this synthetic biologic versus the added clinical benefit should be carefully considered when being used in the revision hip setting.

Long-term safety and efficacy of human bone morphogenetic protein (HBMP) in the treatment of resistant non-unions and failed arthrodesis

The bone morphogenetic protein (BMP) has emerged as a suitable alternative to autogenous cancellous bone grafting and despite current knowledge about its mechanism; few studies provide evidence about the long-term safety of BMP. The aim of this investigation is to determine if BMP implantation is a safe and effective agent in a long-term setting for the treatment of patients with resistant non-unions and failed arthrodesis. This study is a retrospective case series study that was conducted on 55 patients who had received BMP. Collected data included all related surgical history, and clinical and X-ray data both pre-operatively and post-operatively. All patients were scheduled for follow-up evaluations at one week and 1, 3, 6, and 12 months post-operatively. Seven patients (13%) experienced adverse events related to their surgery with hBMP. Six patients (11%) experienced persistent non-union; five of these underwent further revision surgery. One patient (2%) developed an infected non-union. No patients experienced tumor induction, allergic reaction to hBMP. The remaining 48 patients achieved osseous union within six months of hBMP implantation. This study differs from previous studies that the use of hBMP is a safe and efficacious treatment method for resistant non-unions and failed arthrodesis in the long-term setting.

Upper limb non-unions treated with BMP-7: efficacy and clinical results

The management of upper limb non-unions can be challenging and often with unpredictable outcomes. In this study we present our experience with the use of BMP-7 in the treatment of upper limb non-unions. Between 2004 and 2011 all consecutive patients who were treated with BMP-7 were followed up prospectively until fracture union. Fracture union was assessed with regular radiological and clinical assessment. At the final follow up clinical assessment included the short Disabilities of the Arm, Shoulder and Hand (DASH) score. The minimum follow up was 12 months (12-36). In total 42 patients met the inclusion criteria with a mean age of 47 years. Anatomical distribution of the nonunion sites included 19 cases of mid/proximal forearm, 14 humeri, 6 distal radius and 3 clavicle. 35 patients had atrophic non-union, 11 had previous open fractures, and 10 had bone loss (range 1-3 cm). The mean number of operations performed and the mean time from injury to BMP-7 application was 1.5 and 26 months, respectively. 40 fractures had both clinical and radiological union whereas 2 patients had partial radiological union but a pain free range of motion. BMP-7 was applied in isolation in 1 case and in 41 cases the application was combined with autologous bone grafting. DASH scores were available at final follow up in 23 (55%) patients with a mean of 33 score (range 2-86.4). This study supports the view that the combination of ABG and BMP-7 can be considered as a successful treatment modality for the treatment of recalcitrant upper limb non-unions. Further studies preferably randomised controlled trials are desirable to throw more light into the role of BMP-7 in the treatment of upper limb nonunions.

Active implant combining human stem cell microtissues and growth factors for bone-regenerative nanomedicine

AIMS

Mesenchymal stem cells (MSCs) from adult bone marrow provide an exciting and promising stem cell population for the repair of bone in skeletal diseases. Here, we describe a new generation of collagen nanofiber implant functionalized with growth factor BMP-7 nanoreservoirs and equipped with human MSC microtissues (MTs) for regenerative nanomedicine.

MATERIALS & METHODS

By using a 3D nanofibrous collagen membrane and by adding MTs rather than single cells, we optimize the microenvironment for cell colonization, differentiation and growth.

RESULTS & CONCLUSION

Furthermore, in this study, we have shown that by combining BMP-7 with these MSC MTs in this double 3D environment, we further accelerate bone growth in vivo. The strategy described here should enhance the efficiency of therapeutic implants compared with current simplistic approaches used in the clinic today based on collagen implants soaked in bone morphogenic proteins.

Orthobiologics in Foot and Ankle Surgery

Exploration into the molecular aspects of the healing process has led to the development of autologous and recombinant biologic agents. These products, collectively known as orthobiologics, have the potential to optimize favorable outcomes with respect to bone and soft-tissue restoration and to maximize the natural healing response. These orthobiologics include platelet-derived growth factor, bone morphogenetic proteins, and platelet-rich plasma. Although the usefulness of these growth factors is well described in various fields of surgery, few data exist to support or oppose the specific application of growth factors in foot and ankle surgery.

The effect of low-level diode laser therapy on early differentiation of osteoblast via BMP-2/TGF-β1 and its receptors

OBJECTIVES

The objective of this study was to determine the effect of LLDL therapy on the gene expression of osteoblast markers of growth and differentiation.

MATERIALS AND METHODS

The MG-63 cell line was exposed to diode laser (ezLase) of 940 nm at 1-1.5 W and 3-4 J, and gene expressions (Runx-2, alkaline phosphatase [ALP], type I collagen [Col-I], osterix [OSX], osteocalcin [OSC], osteoprotegerin [OPG], bone morphogenetic protein [BMP]-2 and -7, transforming growth factor-β1 [TGF-β1], and TGF-β receptors [TGF-β R1, TGF-β R2; TGF-β R3]) were evaluated by quantitative RT-PCR.

RESULTS

LLDL treatment stimulated the expression of osteoblast differentiation markers ALP, Col-I, Runx-2, and OSX in relation to the doses applied (P < 0.05), but no changes were detected in OSC, OPG, or BMP-7 at any study dose. This effect may be mediated by TGF-β1 and BMP-2, given that the treatment increased their expression and that of TGF-β receptors R1, R2, and R3 (P < 0.001).

CONCLUSION

These results suggest that the biostimulatory effect of laser therapy on osteoblasts may be attributable to the release of autocrine factors in response to the irradiation. A clinical trial is warranted to test its therapeutic usefulness in bone tissue regeneration and to define a treatment protocol.

Tibiotalocalcaneal arthrodesis using a straight intramedullary nail

BACKGROUND

Tibiotalocalcaneal (TTC) arthrodesis is a proven solution for severe hindfoot arthropathy that reestablishes stability for plantigrade gait and alleviates pain, while correcting deformity. Intramedullary nailing is an effective option for fixation. The aim of this study was to determine clinical outcome, analyze the fusion rate, and determine final hindfoot alignment in a consecutive series of patients using a single-design straight intramedullary nail.

METHODS

This study evaluated 63 patients treated between 2006 and 2010 with at least 36 months of follow-up. Ten patients were excluded because of study inclusion criteria, and 4 were lost to follow-up, leaving 49 patients available for review. The average follow-up was 70.7 ± 15.1 months.

RESULTS

The American Orthopaedic Foot and Ankle Society score improved from 29.7 ± 15.1 before arthrodesis to 65.8 ± 14.6 after (P < .001) with 83.7% (41/49) of patients stating they were satisfied or very satisfied with the outcome. The hindfoot angle improved from -3 ± 15 degrees (varus) before the arthrodesis to 3.5 ± 4 degrees (valgus) after; the tibiotalar angle averaged 103 ± 4.2 degrees after the arthrodesis. Fusion occurred in both joints in 86% (42/49) of patients and in 93% (91/98) of all joints. The average time to fusion was 4.5 ± 2 months. Current smokers had a significantly (P = .03) higher risk of complications. Use of an allograft, with or without bone morphogenetic protein 2, led to comparable results even in the presence of a large bone defect.

CONCLUSION

These results are comparable to previously published studies using intramedullary nailing to achieve tibiotalocalcaneal arthrodesis. The complication concerns typically associated with straight nails were not found. We recommend using a retrograde intramedullary nail for the fixation of TTC arthrodesis and adding an allograft in cases of significant bone loss.

LEVEL OF EVIDENCE

Level IV, consecutive case series.

Bone morphogenetic protein and orthopaedic surgery: can we legitimate its off-label use?

PURPOSE

Bone morphogenetic proteins (BMP) are recombinant osteoinductive proteins with their primary role being to promote bone formation. The off-label use of BMP in orthopaedic surgery has dramatically increased. However, reports of complications with BMP have emerged, and the safety of these proteins in orthopaedics is questioned. The purpose of this review was to evaluate safe situations in which BMP should be used and situations in which their use should be restricted.

METHOD

We recorded all studies from PubMed database from 2002 (date of first authorisation for both BMPs) until January 2014 using "BMP" or "bone morphogenetic protein". Then we screened and extracted all studies dealing with orthopaedic surgery. All situations in which BMP were used, even cases reports, were considered, and complications reported were then listed.

RESULTS

Situations in which it seems safe and efficient to use BMP are long-bone nonunions, or arthrodesis as an alternative or combined to autograft in small-bone loss. Surgeons and patients should be aware of transient aseptic wound swelling when BMP is located superficially. The use of BMP in spine surgery for intersomatic fusion is efficient but should be restricted to approaches that respect the vertebral canal to avoid neurological complications.

CONCLUSION

This review is an off-label map of BMP use in orthopaedics during the past 10 years. Our results could provide a useful tool to help decisions around when to use a BMP in a specific complex, and sometimes off-label, situation.

Ankle arthrodesis fusion rates for mesenchymal stem cell bone allograft versus proximal tibia autograft

Ankle arthrodesis is commonly used in the treatment of ankle arthritis. The present study compared mesenchymal stem cell (MSC) bone allografts and proximal tibia autografts as adjuncts in performing ankle arthrodesis. A total of 109 consecutive ankle fusions performed from 2002 to 2008 were evaluated retrospectively. Of the 109 fusions, 24 were excluded from the present study, leaving 85 patients who had undergone ankle arthrodesis. Of the 85 patients, 41 had received a proximal tibia autograft and 44, an MSC bone allograft. These 2 groups were reviewed and compared retrospectively at least 2 years postoperatively for the overall fusion rate, interval to radiographic fusion, and interval to clinical fusion. A modified and adjusted American College of Foot and Ankle Surgeons ankle scale was used to measure patient satisfaction. The overall fusion rate was 84.1% in the MSC bone allograft group and 95.1% in the proximal tibia autograft group (p = .158). The corresponding mean intervals to radiographic fusion were 13.0 ± 2.5 weeks and 11.3 ± 2.8 weeks (p ≤ .001). The interval to clinical fusion was 13.1 ± 2.1 weeks and 11.0 ± 1.5 weeks (p ≤ .001) in the MSC bone allograft and proximal tibia autograft group, respectively. No statistically significant difference was found in the fusion rates between the MSC bone allograft and proximal tibia autograft groups. Also, no statistically significant difference was found between the preoperative and postoperative scores using a modified and adjusted American College of Foot and Ankle Surgeons ankle scale between the 2 groups (p = .41 and p = .44, respectively). A statistically significant delay to radiographic and clinical fusion was present in the MSC bone allograft group compared with the proximal tibia autograft group; however, no difference was found in patient satisfaction.

Effectiveness and Complications Associated With Recombinant Human Bone Morphogenetic Protein-2 Augmentation of Foot and Ankle Fusions and Fracture Nonunions

BACKGROUND

Recombinant human bone morphogenetic protein-2 (rhBMP-2) has been used to augment bone healing and fusion in a variety of orthopaedic conditions. However, there is a paucity of data evaluating the potential benefits of its use in foot and ankle surgery. The purpose of this study was to investigate the effectiveness and associated complications with the use of rhBMP-2 in high-risk foot and ankle fusions and fracture nonunions.

METHODS

A total of 51 cases in 48 patients undergoing foot and ankle fusions or fracture nonunion revisions and considered at high risk for subsequent nonunion were identified through a retrospective review in which rhBMP-2 was used as an augment for bone healing. Rate of union, time to union, and associated complications were evaluated.

RESULTS

Forty-seven of 51 high-risk cases treated with rhBMP-2 united for a per-case union rate of 92.2%. Seventy-eight of 82 individual sites treated with rhBMP-2 united for a per-site union rate of 95.1%. Of the successful unions, the mean time to union was 111 days (95% confidence interval, 101-121). There were no statistically significant differences in time to union with regard to supplementation with bone allograft or autograft or size of rhBMP-2 kit used. Complication rates were low.

CONCLUSION

rhBMP-2 was a safe and apparently effective adjunct to bony union in high-risk foot and ankle surgeries. Further randomized controlled trials are warranted.

LEVEL OF EVIDENCE

Level IV, retrospective case series.

Megaprosthesis in large bone defects: opportunity or chimaera?

INTRODUCTION

The development of new megaprosthesis for the treatment of large bone defects provides important options to orthopaedic oncologic surgeons for the replacement of skeletal segments, such as the long bones of the upper and lower limbs and the relative joints. We implanted megaprosthesis using either a one-step or two-step technique depending on the patient's condition. The aim of this study was to evaluate retrospectively both clinical and radiological outcomes in patients who underwent lower limb megaprosthesis implant.

MATERIALS AND METHODS

A total of 32 patients were treated with mono- and bi-articular megaprosthesis subdivided as follows: proximal femur, distal femur, proximal tibia and total femur. The mean follow-up of patients was about 18 months (range 3 months to 5 years). Clinical and serial radiographic evaluations were conducted using standard methods (X-ray at 45 days, 3, 6, 12, 18 and 24 months) and blood parameters of inflammation were monitored for at least 2 months.

RESULTS

Although the mean length of follow-up was only 18 months, the first patients to enter the study were monitored for 5 years and showed encouraging clinical results, with good articulation of the segments, no somato-sensory or motor deficit and acceptable functional recovery. During surgery and, more importantly, in pre-operative planning, much attention should be given to the evaluation of the extensor apparatus, preserving it and, when necessary, reinforcing it with tendon substitutes.

DISCUSSION

Megaprosthesis in extreme cases of severe bone loss and prosthetic failure is a potential solution for the orthopaedic surgeon. In oncological surgery, the opportunity to restore functionality to the patient (although not ad integrum) is important for both the patient and the surgeon. The high mortality associated with cancer precludes long-term patient follow-up; therefore, there is a lack of certainty about the survival of this type of prosthesis and any medium- to long-term complications that may occur. Nevertheless, patients should be considered as an oncologic patient, not because of the disease, but because of the limited therapeutic options available.

CONCLUSIONS

Megaprosthesis provides a valuable opportunity to restore functionality to patients with highly disabling diseases.

Release of growth factors and the effect of age, sex, and severity of injury after long bone fracture. A preliminary report

BACKGROUND AND PURPOSE

The systemic response after fracture is regulated by a complex mechanism involving numerous growth factors. In this study, we analyzed the kinetics of key growth factors following lower-limb long bone fracture.

MATERIALS AND METHODS

Human serum was isolated from 15 patients suffering from lower-limb long bone fracture (tibia/femur) requiring surgical fixation. The levels of platelet-derived growth factor (PDGF-BB), vascular edothelial growth factor (VEGF), insulin growth factor-I (IGF-I), and transforming growth factor β1 (TGF-β1) were assayed by colorimetric ELISA at different time points during the first week after fracture. 10 healthy volunteers made up the control group of the study. Serum levels of the growth factors measured were compared to age, sex, and injury severity score.

RESULTS

We found that there was a decline in the levels of PDGF-BB, IGF-I and TGF-β1 during the first 3 days after fracture. However, VEGF levels remained unchanged. The levels of all the growth factors studied then increased, with the highest concentrations noted at day 7 after surgery. No correlation was found between circulating levels of growth factors and age, injury severity score (ISS), blood loss, or fluid administration.

INTERPRETATION

There are systemic mitogenic and osteogenic signals after fracture. Important growth factors are released into the peripheral circulation, but early after surgery it appears that serum levels of key growth factors fall. By 7 days postoperatively, the levels had increased considerably. Our findings should be considered in cases where autologous serum is used for ex vivo expansion of mesenchymal stem cells. There should be further evaluation of the use of these molecules as biomarkers of bone union.

The influence of environmental factors on bone tissue engineering

Bone repair and regeneration are dynamic processes that involve a complex interplay between the substrate, local and systemic cells, and the milieu. Although each constituent plays an integral role in faithfully recreating the skeleton, investigators have long focused their efforts on scaffold materials and design, cytokine and hormone administration, and cell-based therapies. Only recently have the intangible aspects of the milieu received their due attention. In this review, we highlight the important influence of environmental factors on bone tissue engineering.

Ankle arthrodesis: a literature review

Ankle joint arthrodesis should be considered the gold standard procedure for end-stage ankle arthritis in the appropriate patient. Incisional approach and fixation technique should be based on the patient and specific needs. Arthrodesis can be achieved with adequate resection of cartilage, good compression across the fusion site, stable fixation, proper postoperative protocol, and patient compliance. It is important to remember that positioning of the ankle joint is a keystone in ankle arthrodesis. There are complications that can arise from the ankle fusion, including the need for further surgical intervention owing to arthritis in the subtalar and midtarsal joints.

TGF-β and BMP signaling in osteoblast differentiation and bone formation

Transforming growth factor-beta (TGF-β)/bone morphogenic protein (BMP) signaling is involved in a vast majority of cellular processes and is fundamentally important throughout life. TGF-β/BMPs have widely recognized roles in bone formation during mammalian development and exhibit versatile regulatory functions in the body. Signaling transduction by TGF-β/BMPs is specifically through both canonical Smad-dependent pathways (TGF-β/BMP ligands, receptors and Smads) and non-canonical Smad-independent signaling pathway (e.g. p38 mitogen-activated protein kinase pathway, MAPK). Following TGF-β/BMP induction, both the Smad and p38 MAPK pathways converge at the Runx2 gene to control mesenchymal precursor cell differentiation. The coordinated activity of Runx2 and TGF-β/BMP-activated Smads is critical for formation of the skeleton. Recent advances in molecular and genetic studies using gene targeting in mice enable a better understanding of TGF-β/BMP signaling in bone and in the signaling networks underlying osteoblast differentiation and bone formation. This review summarizes the recent advances in our understanding of TGF-β/BMP signaling in bone from studies of genetic mouse models and human diseases caused by the disruption of TGF-β/BMP signaling. This review also highlights the different modes of cross-talk between TGF-β/BMP signaling and the signaling pathways of MAPK, Wnt, Hedgehog, Notch, and FGF in osteoblast differentiation and bone formation.

Allograft cellular bone matrix as an alternative to autograft in hindfoot and ankle fusion procedures

This report summarizes the radiographic results of Osteocel Plus in 20 hindfoot and ankle fusions at a single center. The patient population was 40% female with an average age of 57.9 ± 16.1 years. Average body mass index was 33.8 ± 9.1. Risk factors included 3 smokers and 6 patients with diabetes. Primary surgical indications included trauma (50%), Charcot arthropathy (15%), foot drop with osteoarthritis (20%), primary osteoarthritis (10%), and total talar extrusion (5%). Nine patients had a history of prior hindfoot surgery in the same foot; however, only 2 of the cases reported in this series were revisions due to a failed prior surgery; the remaining 7 were treated for correction of a traumatic deformity (n = 5) or diagnosis at a new site in the same foot (n = 2). Treatment included subtalar joint arthrodesis (50%), ankle arthrodesis (40%), triple fusion (5%), and tibial-calcaneal-calcaneal-cuboid arthrodesis (5%). Solid fusion was observed in 100% of patients by the 6-month evaluation. Average time to fusion was 13.5 weeks. Although patients with a prior surgery trended toward a longer time to fusion than patients who underwent their first hindfoot and ankle procedure (14.4 ± 5.3 vs. 12.6 ± 5.7 weeks), the difference was not statistically significant (p = .47). There was no evidence of graft rejection or failure. This series demonstrates that mesenchymal stem cell-based bone allograft is a safe and effective bone-healing material with a high radiographic success rate in foot and ankle arthrodeses with successful and timely fusion rates.

The indications and use of bone morphogenetic proteins in foot, ankle, and tibia surgery

Tissue engineering is an area of rapid growth. Tissue engineering in orthopedic surgery involves the use of growth factors, mesenchymal stem cells, and scaffolds, individually or in combination, toward the growth and restoration of various musculoskeletal tissues, such as ligaments, tendons, muscles, nerves, and bone. These advances are constantly evolving in foot and ankle surgery as well. Bone morphogenetic proteins (BMPs) have played an integral role in the advancement of tissue engineering strategies across multiple orthopedic subspecialities and have proved to play a role in the development of bone and musculoskeletal tissues. BMPs have recently been applied in several areas of foot and ankle surgery, including acute fracture augmentation, nonunions, and arthrodesis, with promising results. This article reviews the key aspects of clinical translation of strategies in tissue engineering as well as current applications and results of BMP use in tibia, foot, and ankle surgery. Future applications of BMP and novel materials in foot and ankle surgery are also reviewed.