RhBMP-7 for the treatment of nonunion of fractures of long bones

Phase III clinical trial of autologous CD34 + cell transplantation to accelerate fracture nonunion repair

BACKGROUND

We previously demonstrated that CD34 + cell transplantation in animals healed intractable fractures via osteogenesis and vasculogenesis; we also demonstrated the safety and efficacy of this cell therapy in an earlier phase I/II clinical trial conducted on seven patients with fracture nonunion. Herein, we present the results of a phase III clinical trial conducted to confirm the results of the previous phase studies using a larger cohort of patients.

METHODS

CD34 + cells were mobilized via administration of granulocyte colony-stimulating factor, harvested using leukapheresis, and isolated using magnetic cell sorting. Autologous CD34 + cells were transplanted in 15 patients with tibia nonunion and 10 patients with femur nonunion, who were followed up for 52 weeks post transplantation. The main outcome was a reduction in time to heal the tibia in nonunion patients compared with that in historical control patients. We calculated the required number of patients as 15 based on the results of the phase I/II study. An independent data monitoring committee performed the radiographic assessments. Adverse events and medical device failures were recorded.

RESULTS

All fractures healed during the study period. The time to radiological fracture healing was 2.8 times shorter in patients with CD34 + cell transplantation than in the historical control group (hazard ratio: 2.81 and 95% confidence interval 1.16-6.85); moreover, no safety concerns were observed.

CONCLUSIONS

Our findings strongly suggest that autologous CD34 + cell transplantation is a novel treatment option for fracture nonunion.

TRIAL REGISTRATION

UMIN-CTR, UMIN000022814. Registered on 22 June 2016.

Bone Morphogenic Protein for Upper Extremity Fractures: A Systematic Review

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Effect of Recombinant Human Bone Morphogenetic Protein-2 (rhBMP-2) with Hydroxyapatite Carrier in Induced Membrane Technique: A Retrospective Propensity Score-Matched Study

OBJECTIVES

To determine the effect of recombinant human bone morphogenetic protein-2 (rhBMP-2) with hydroxyapatite (HA) carrier augmentation in managing critical-sized bone defect (CSBD) with induced membrane technique (IMT).

DESIGN

Retrospective comparative study.

SETTING

Academic level I trauma center.

PATIENTS/PARTICIPANTS

The study included 14 patients who underwent rhBMP-2 with HA carrier (rhBMP-2/HA) augmentation in IMT for managing CSBD (BMP group). Moreover, 14 patients who underwent IMT without rhBMP-2 augmentation were matched by propensity score analysis (non-BMP group).

INTERVENTION

IMT with or without rhBMP-2/HA augmentation.

MAIN OUTCOME MEASUREMENT

Changes in quality and quantity measurements of grafted bone to regenerated bone using serial computed tomography.

RESULTS

In the BMP and non-BMP groups, the changes in densities from grafted bone to regenerated bone were +379.63 Hounsfield unit and +248.55 Hounsfield unit (P = 0.034), changes in dense bone percentage were +37.52% and +23.31% (P = 0.027), corticalization rates under the plate were 79.70% and 39.30% (P = 0.007), changes in volume were -20.77% and -23.35% (P = 0.812), union rates were 85.71% and 78.57% (P = 0.622), numbers of patients requiring additional procedures were 4 and 3 (P = 0.663), and time to union were 316.3 and 585.45 days (P = 0.040), respectively.

CONCLUSIONS

RhBMP-2/HA augmentation increases the density of regenerated bone, enhances corticalization under the plate, and shortens the time to union while managing CSBD with IMT.

LEVEL OF EVIDENCE

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

Risk Factors and Consequences of Lower Extremity Fracture Nonunions in Veterans With Spinal Cord Injury

We used Veterans Health Administration (VHA) national administrative data files to identify a cohort (fiscal years 2005–2014) of veterans with spinal cord injuries and disorders (SCID) to determine risk factors for and consequences of lower extremity fracture nonunions. Odds ratios (OR) for fracture nonunion were computed using multivariable‐adjusted logistic regression models. We identified three risk factors for nonunion: (i) older age (OR = 2.29; 95% confidence interval [CI] 1.21–4.33), (ii) longer duration of SCID (OR = 1.02; 95% CI 1.00–1.04), and (iii) fracture site (distal femur), with OR (comparison distal femur) including distal tibia/fibula (OR = 0.14; 95% CI 0.09–0.24), proximal tibia/fibula (OR = 0.19; 95% CI 0.09–0.38), proximal femur (OR = 0.10; 95% CI 0.04–0.21), and hip (OR = 0.13; 95% CI 0.07–0.26). Nonunions resulted in multiple complications, with upwards of 1/3 developing a pressure injury, 13% osteomyelitis, and almost 25% requiring a subsequent amputation. Our data have identified a high‐risk population for fracture nonunion of older veterans with a long duration of SCID who sustain a distal femur fracture. In view of the serious complications of these nonunions, targeted interventions in these high‐risk individuals who have any signs of delayed union should be considered. © 2021 The Authors. JBMR Plus published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research. This article has been contributed to by US Government employees and their work is in the public domain in the USA.

Long-term patient-related quality of life after successfully treated aseptic non-unions of the long bones

BACKGROUND

Non-union after fracture depicts a devastating complication in trauma surgery and studies assessing patient-reported outcome measures after stable bone consolidation are rare. Therefore, we aimed to evaluate the long-term impact of aseptic long bone non-union on the patients' physical health state and psychological wellbeing. For this purpose, quality of life after successful surgical treatment of long bone non-union was assessed.

METHODS

Sixty-one patients with aseptic long bone non-union surgically treated in our department between November 2009 and March 2019 with achieved bone consolidation were included. Quality of life was evaluated with the EQ-5D and SF-36 outcome instruments as well as with an ICD-10 based symptom rating (ISR) and compared to normative data.

RESULTS

With a minimum follow-up time of one year after the last surgery (mean 4.7 ± 2.7 years) the mean physical health component score of the SF-36 was 38.9 ± 13.7 and the mean mental health component score of the SF-36 was 49.0 ± 5.9, indicating lower quality of life compared to German normative values of 48.4 ± 9.4 (p < .001) and 50.9 ± 8.8 (p = 1.61), respectively. The mean EQ-5D index value reached 0.827 ± 0.18 with an EQ-5D VAS rating of 64.4 ± 21.5 compared to scores of 0.922 (p < .001) and 72.9 ± 1.1 (p < .001) obtained from an age-matched reference population. Mean scores of the ISR did not reveal significant psychological symptom burden in any scale, while an individual analysis showed moderate to severe impairments in 11.5% of the patients in total.

CONCLUSION

Even 4.7 years on average after surgically successful treatment of aseptic long bone non-union, patients still report significant lower quality of life in comparison to normative data. Future clinical studies on non-unions should focus on patient-related outcome measures. Newly emerging treatment strategies and interdisciplinary approaches should be implemented to improve the overall quality of life of non-union patients.

Intervertebral Disc Degeneration: The Role and Evidence for Non-Stem-Cell-Based Regenerative Therapies

The use of non-stem-cell-based regenerative medicine therapies for lumbar discogenic pain is an area of growing interest. Although the intervertebral disc is a largely avascular structure, cells located within the nucleus pulposus as well as annulus fibrosis could be targeted for regenerative and restorative treatments. Degenerative disc disease is caused by an imbalance of catabolic and anabolic events within the nucleus pulposus. As catabolic processes overwhelm the environment within the nucleus pulposus, proinflammatory cytokines increase in concentration and lead to further disc degeneration. Non-stem-cell-based therapies, which include growth factor therapy and other proteins, can lead to an increased production of collagen and proteoglycans within the disc.

Comparison of bone morphogenetic protein and autologous grafting in the treatment of limb long bone nonunion: a systematic review and meta-analysis

BACKGROUND

Bone morphogenetic proteins (BMPs) have strong bone induction properties and can promote healing of fractures and other defects. However, BMP treatment efficacy for long bone nonunion remains controversial. The aim of this meta-analysis was to synthetically evaluate the advantages and disadvantages of BMP plus bone grafting (observation group) versus autologous bone grafting (control group) for limb long bone nonunion.

METHODS

PubMed, Embase, Web of Science, Cochrane Library, OVID, CNKI, Weipu Journal, Chinese Biomedical Literature, and WanFang were searched for randomized and non-randomized controlled trials published before November 2019. A meta-analysis of outcome indicators was performed using RevMan 5.3 and Stata 12.0.

RESULTS

Five randomized and four non-randomized controlled trials involving 30-124 cases were included, with a total of 655 nonunion cases. There were no significant group differences in postoperative healing rate, infection, and secondary operation rates (P > 0.05), but the study group demonstrated significantly shorter mean healing time (WMD = - 1.27, 95%CI - 1.67 to - 0.88, P < 0.00001), a greater frequency of excellent/good post-treatment limb function (RR = 1.18, 95%CI 1.01-1.39, P = 0.04), and lower intraoperative blood loss (P < 0.05). Alternatively, the hospitalization cost was significantly higher in the study group (P < 0.01).

CONCLUSIONS

Bone morphogenetic protein is a viable alternative to autologous bone grafting, with potential advantages of accelerated fracture healing and improved postoperative function.

Early efficacy evaluation of mesenchymal stromal cells (MSC) combined to biomaterials to treat long bone non-unions

BACKGROUND AND STUDY AIM

Advanced therapy medicinal products (ATMP) frequently lack of clinical data on efficacy to substantiate a future clinical use. This study aims to evaluate the efficacy to heal long bone delayed unions and non-unions, as secondary objective of the EudraCT 2011-005441-13 clinical trial, through clinical and radiological bone consolidation at 3, 6 and 12 months of follow-up, with subgroup analysis of affected bone, gender, tobacco use, and time since the original fracture.

PATIENTS AND METHODS

Twenty-eight patients were recruited and surgically treated with autologous bone marrow derived mesenchymal stromal cells expanded under Good Manufacturing Practices, combined to bioceramics in the surgical room before implantation. Mean age was 39 ± 13 years, 57% were males, and mean Body Mass Index 27 ± 7. Thirteen (46%) were active smokers. There were 11 femoral, 4 humeral, and 13 tibial non-unions. Initial fracture occurred at a mean ± SD of 27.9 ± 31.2 months before recruitment. Efficacy results were expressed by clinical consolidation (no or mild pain if values under 30 in VAS scale), and by radiological consolidation with a REBORNE score over 11/16 points (value of or above 0.6875). Means were statistically compared and mixed models for repeated measurements estimated the mean and confidence intervals (95%) of the REBORNE Bone Healing scale. Clinical and radiological consolidation were analyzed in the subgroups with Spearman correlation tests (adjusted by Bonferroni).

RESULTS

Clinical consolidation was earlier confirmed, while radiological consolidation at 3 months was 25.0% (7/28 cases), at 6 months 67.8% (19/28 cases), and at 12 months, 92.8% (26/28 cases including the drop-out extrapolation of two failures). Bone biopsies confirmed bone formation surrounding the bioceramic granules. All locations showed similar consolidation, although this was delayed in tibial non-unions. No significant gender difference was found in 12-month consolidation (95% confidence). Higher consolidation scale values were seen in non-smoking patients at 6 (p = 0.012, t-test) and 12 months (p = 0.011, t-test). Longer time elapsed after the initial fracture did not preclude the occurrence of consolidation.

CONCLUSION

Bone consolidation was efficaciously obtained with the studied expanded hBM-MSCs combined to biomaterials, by clinical and radiological evaluation, and confirmed by bone biopsies, with lower consolidation scores in smokers.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

LEVEL OF EVIDENCE

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

Topical cutaneous application of carbon dioxide via a hydrogel for improved fracture repair: results of phase I clinical safety trial

Background

Clinicians have very limited options to improve fracture repair. Therefore, it is critical to develop a new clinically available therapeutic option to assist fracture repair biologically. We previously reported that the topical cutaneous application of carbon dioxide (CO₂) via a CO₂ absorption-enhancing hydrogel accelerates fracture repair in rats by increasing blood flow and angiogenesis and promoting endochondral ossification. The aim of this study was to assess the safety and efficacy of CO₂ therapy in patients with fractures.

Methods

Patients with fractures of the femur and tibia were prospectively enrolled into this study with ethical approval and informed consent. The CO₂ absorption-enhancing hydrogel was applied to the fractured lower limbs of patients, and then 100% CO₂ was administered daily into a sealed space for 20 min over 4 weeks postoperatively. Safety was assessed based on vital signs, blood parameters, adverse events, and arterial and expired gas analyses. As the efficacy outcome, blood flow at the level of the fracture site and at a site 5 cm from the fracture in the affected limb was measured using a laser Doppler blood flow meter.

Results

Nineteen patients were subjected to complete analysis. No adverse events were observed. Arterial and expired gas analyses revealed no adverse systemic effects including hypercapnia. The mean ratio of blood flow 20 min after CO₂ therapy compared with the pre-treatment level increased by approximately 2-fold in a time-dependent manner.

Conclusions

The findings of the present study revealed that CO₂ therapy is safe to apply to human patients and that it can enhance blood flow in the fractured limbs.

Trial registration

This study has been registered in the UMIN Clinical Trials Registry (Registration number: UMIN000013641, Date of registration: July 1, 2014).

Physical Health and Psychological Outcomes in Adult Patients with Long-bone Fracture Non-unions: Evidence Today

Background: Research has suggested that bone fractures can hinder the health status of patients’ life. However, limited research has examined the impact that the healing process of a fracture has on the physical health and psychological state of individuals, particularly in considering the short- and long-term impact of having a fracture that fails to heal and drops into a non-union. The aim of this systematic review is to better understand the impact of fracture non-union to physical health and to respective psychological outcomes. Methods: Electronic databases ‘PubMed’, ‘Cochrane’, ‘PsycInfo’, ‘Medline’, ‘Embase’, ‘Web of Science’, and ‘CINAHL’ were used. Search terms used were nonunion OR non-union OR “non union” OR “long bone” OR “delayed union” AND “quality of life” OR qol OR depression OR anxiety OR psycholog* OR PTSD OR “post-traumatic stress disorder”. Studies published in the years 1995 to 2018 were included. Two independent reviewers carried out screening and data extraction. Studies were included if (1) participants were adult (human) patients with a traumatic non-union secondary to fracture/s; (2) outcomes measured included physical health and psychological wellbeing (e.g., PTSD, psychological trauma, depression, anxiety, etc.). Studies received emphasis if they compared those outcomes between: (1) The “non-union” group to a normative, matched population and (2) the “non-union group” to the same group after union was achieved. However, studies that did not use comparison groups were also included. Results: Out of the 1896 papers identified from our thorough literature search, 13 met the inclusion criteria. Quality assessment was done by the Methodological Index for Non-Randomized Studies (MINORS). Findings suggested that non-unions had a detrimental impact on physical health, and psychological difficulties often after recovery. Conclusions: Patients who experience a long bone non-union are at risk of greater psychological distress and lower physical health status. There is a need for early identification of psychological distress in patients with fracture non-unions and psychological provision should become part of the available treatment.

Recombinant Human Bone Morphogenetic Protein 7 Exerts Osteo-Catabolic Effects on Bone Grafts That Outweigh Its Osteo-Anabolic Capacity

This study aimed to investigate the effects of recombinant human bone morphogenetic protein (rhBMP-7) on human cancellous bone grafts (BGs) while differentiating between anabolic and catabolic events. Human BGs alone or supplemented with rhBMP-7 were harvested 14 weeks after subcutaneous implantation into NOD/Scid mice, and studied via micro-CT, histomorphometry, immunohistochemistry and flow cytometry. Immunohistochemical staining for human-specific proteins made it possible to differentiate between grafted human bone and newly formed murine bone. Only BGs implanted with rhBMP-7 formed an ossicle containing a functional hematopoietic compartment. The total ossicle volume in the BMP⁺ group was higher than in the BMP^- group (835 mm³ vs. 365 mm³, respectively, p < 0.001). The BMP⁺ group showed larger BM spaces (0.47 mm vs. 0.28 mm, p = 0.002) and lower bone volume-to-total volume ratio (31% vs. 47%, p = 0.002). Immunohistochemical staining for human-specific proteins confirmed a higher ratio of newly formed bone area (murine) to total area (0.12 vs. 0.001, p < 0.001) in the BMP+ group, while the ratio of grafted bone (human) area to total area was smaller (0.14 vs. 0.34, p = 0.004). The results demonstrate that rhBMP-7 induces BG resorption at a higher rate than new bone formation while creating a haematopoietic niche. Clinicians therefore need to consider the net catabolic effect when rhBMP-7 is used with BGs. Overall, this model indicates its promising application to further decipher BMPs action on BGs and its potential in complex bone tissue regeneration.

Comparison of the clinical effectiveness of Bone Morphogenic Protein (BMP) -2 and -7 in the adjunct treatment of lower limb nonunions

BACKGROUND

Substantial evidence exists demonstrating the individual effectiveness of both rhBMP-2 and -7 in the treatment of nonunions, data comparing the clinical effectiveness of adjunct rhBMP-2 and -7 remains scarce. Therefore, we examined our large single-center case series to compare the clinical effectiveness of both rhBMP-2 and -7 in non-union therapy aiming to answer: - Does a certain type of BMP have an advantageous effect on radiological outcome of applied lower limb non-union therapy? - Does application of a certain type of BMP have an advantageous effect on radiological outcome of infected lower limb nonunions? - Are there any additional risk factors associated with inferior outcome in context with an adjunct BMP treatment?

HYPOTHESIS

Both BMPs have the same effect on the radiological outcome of surgically treated lower limb nonunions.

PATIENTS AND METHODS

Single-center retrospective database analysis of a case series of patients with lower limb long bone nonunions receiving either a one- or two-stage (Masquelet-) procedure based on the "diamond concept" with application of rhBMP-2 or -7. The "diamond concept" summarizes core factors that need to be present to achieve bone healing. In particular, these factors relate to the optimization of the mechanical (stability) and biological environment (sufficient osteogenic and angiogenic cells, osteoconductive scaffolds and growth factors). All medical data from patients that received surgical treatment between 01/01/2010 and 31/12/2016 were assessed. In total, 356 patients were treated with BMPs and 156 patients 18 years or older with non-union of their tibia or femur having a follow-up of at least 1 year were included. Consolidation in context with type of rhBMP was compared and the influence of relevant risk factors assessed.

RESULTS

Consolidation rate was significantly higher in patients treated with rhBMP-2 (rhBMP-2: 42/46 (91%) vs. rhBMP-7: 64/110 (58%); p<0.001). In particular, application of rhBMP-2 increased the likelihood of consolidation for tibial nonunions (OR 32.744; 95%CI: 2.909-368.544; p=0.005) and when used in two-stage therapy (OR 12.095; 95% CI: 2.744-53.314; p=0.001). Furthermore, regression modeling revealed a higher correlation between application of rhBMP-2 and osseous consolidation in infected nonunions (OR 61.062; 95% CI: 2.208-1688.475; p=0.015) than in aseptic nonunions (OR 4.787; 95% CI: 1.321-17.351; p=0.017). Risk factors negatively influencing the outcome of non-union treatment in context with rhBMPs were identified as active smoking (OR 0.357; 95% CI: 0.138-0.927; p=0.024), atrophic nonunion (OR 0.23; 95% CI: 0.061-0.869; p=0.030), higher BMI (OR 0.919; 95% CI: 0.846-0.998; p=0.046) and a larger defect size (OR 0.877; 95% CI: 0.784-0.98; p=0.021).

DISCUSSION

Patients who received rhBMP-2 for the treatment of tibial nonunions and as part of the two-stage treatment had a significantly higher rate of healing compared to patients treated with rhBMP-7 regardless of infection.

LEVEL OF EVIDENCE

III, retrospective case-control study.

Molecular pathogenesis of fracture nonunion

Fracture nonunion, a serious bone fracture complication, remains a challenge in clinical practice. Although the molecular pathogenesis of nonunion remains unclear, a better understanding may provide better approaches for its prevention, diagnosis and treatment at the molecular level. This review tries to summarise the progress made in studies of the pathogenesis of fracture nonunion. We discuss the evidence supporting the concept that the development of nonunion is related to genetic factors. The importance of several cytokines that regulate fracture healing in the pathogenesis of nonunion, such as tumour necrosis factor-α, interleukin-6, bone morphogenetic proteins, insulin-like growth factors, matrix metalloproteinases and vascular endothelial growth factor, has been proven in vitro, in animals and in humans. Nitric oxide and the Wnt signalling pathway also play important roles in the development of nonunion. We present potential strategies for the prevention, diagnosis and treatment of nonunion, and the interaction between genetic alteration and abnormal cytokine expression warrants further investigation.

The translational potential of this article

A better understanding of nonunion molecular pathogenesis may provide better approaches for its prevention, diagnosis and treatment in clinical practice.

Long-term outcome following additional rhBMP-7 application in revision surgery of aseptic humeral, femoral, and tibial shaft nonunion

Background

Surgical revision concepts for the treatment of aseptic humeral, femoral, and tibial diaphyseal nonunion were evaluated. It was analyzed if the range of time to bone healing was shorter, and if clinical and radiological long-term outcome was better following application of additional recombinant human Bone Morphogenetic Protein-7 (rhBMP-7) compared to no additional rhBMP-7 use.

Methods

In a retrospective comparative study between 06/2006 and 05/2013, 112 patients diagnosed with aseptic diaphyseal humerus (22 patients), femur (41 patients), and tibia (49 patients) nonunion were treated using internal fixation and bone graft augmentation. For additional stimulation of bone healing, growth factor rhBMP-7 was locally administered in 62 out of 112 patients. Follow-up studies including clinical and radiological assessment were performed at regular intervals as well as after at least one year following nonunion surgery.

Results

One hundred and two out of 112 (humerus: 19, femur: 37, tibia: 47) nonunion healed within 12 months after revision surgery without any significant differences between the cohort groups. According to the DASH outcome measure for the humerus (p = 0.679), LEFS for the femur (p = 0.251) and the tibia (p = 0.946) as well as to the SF-12 for all entities, no significant differences between the treatment groups were found.

Conclusions

Aseptic diaphyseal nonunion in humerus, femur, and tibia healed irrespectively of additional rhBMP-7 application. Moreover, the results of this study suggest that successful nonunion healing can be linked to precise surgical concepts using radical removal of nonunion tissue, stable fixation and restoration of axis, length and torsion, rather than to the additional use of signaling proteins.

Trial registration

This clinical trial was conducted according to ICMJE guidelines as well as to the approval of the National Medical Board (Ethics Committee of the Bavarian State Chamber of Physicians; TRN: 2016-104) and has been retrospectively registered with the German Clinical Trails Register (TRN: DRKS00012652).

Heterotopic ossification after the use of recombinant human bone morphogenetic protein-7

AIM

To present the incidence of heterotopic ossification after the use of recombinant human bone morphogenetic protein-7 (rhBMP-7) for the treatment of nonunions.

METHODS

Bone morphogenetic proteins (BMPs) promote bone formation by auto-induction. Recombinant human BMP-7 in combination with bone grafts was used in 84 patients for the treatment of long bone nonunions. All patients were evaluated radiographicaly for the development of heterotopic ossification during the standard assessment for the nonunion healing. In all patients (80.9%) with radiographic signs of heterotopic ossification, a CT scan was performed. Nonunion site palpation and ROM evaluation of the adjacent joints were also carried out. Factors related to the patient (age, gender), the nonunion (location, size, chronicity, number of previous procedures, infection, surrounding tissues condition) and the surgical procedure (graft and fixation type, amount of rhBMP-7) were correlated with the development of heterotopic ossification and statistical analysis with Pearsons χ² test was performed.

RESULTS

Eighty point nine percent of the nonunions treated with rhBMP-7, healed with no need for further procedures. Heterotopic bone formation occurred in 15 of 84 patients (17.8%) and it was apparent in the routine radiological evaluation of the nonunion site, in a mean time of 5.5 mo after the rhBMP-7 application (range 3-12). The heterotopic ossification was located at the femur in 8 cases, at the tibia in 6, and at the humerus in οne patient. In 4 patients a palpable mass was present and only in one patient, with a para-articular knee nonunion treated with rhBMP-7, the size of heterotopic ossification affected the knee range of motion. All the patients with heterotopic ossification were male. Statistical analysis proved that patient’s gender was the only important factor for the development of heterotopic ossification (P = 0.007).

CONCLUSION

Heterotopic ossification after the use of rhBMP-7 in nonunions was common but it did not compromise the final clinical outcome in most cases, and affected only male patients.

Bone morphogenetic protein-2 provokes interleukin-18-induced human intervertebral disc degeneration

OBJECTIVES

Interleukin 18 (IL-18) is a regulatory cytokine that degrades the disc matrix. Bone morphogenetic protein-2 (BMP-2) stimulates synthesis of the disc extracellular matrix. However, the combined effects of BMP-2 and IL-18 on human intervertebral disc degeneration have not previously been reported. The aim of this study was to investigate the effects of the anabolic cytokine BMP-2 and the catabolic cytokine IL-18 on human nucleus pulposus (NP) and annulus fibrosus (AF) cells and, therefore, to identify potential therapeutic and clinical benefits of recombinant human (rh)BMP-2 in intervertebral disc degeneration.

METHODS

Levels of IL-18 were measured in the blood of patients with intervertebral disc degenerative disease and in control patients. Human NP and AF cells were cultured in a NP cell medium and treated with IL-18 or IL-18 plus BMP-2. mRNA levels of target genes were measured by real-time polymerase chain reaction, and protein levels of aggrecan, type II collagen, SOX6, and matrix metalloproteinase 13 (MMP13) were assessed by western blot analysis.

RESULTS

The serum level of patients (IL-18) increased significantly with the grade of IVD degeneration. There was a dramatic alteration in IL-18 level between the advanced degeneration (Grade III to V) group and the normal group (p = 0.008) Furthermore, IL-18 induced upregulation of the catabolic regulator MMP13 and downregulation of the anabolic regulators aggrecan, type II collagen, and SOX6 at 24 hours, contributing to degradation of disc matrix enzymes. However, BMP-2 antagonised the IL-18 induced upregulation of aggrecan, type II collagen, and SOX6, resulting in reversal of IL-18 mediated disc degeneration.

CONCLUSIONS

BMP-2 is anti-catabolic in human NP and AF cells, and its effects are partially mediated through provocation of the catabolic effect of IL-18. These findings indicate that BMP-2 may be a unique therapeutic option for prevention and reversal of disc degeneration.Cite this article: S. Ye, B. Ju, H. Wang, K-B. Lee. Bone morphogenetic protein-2 provokes interleukin-18-induced human intervertebral disc degeneration. Bone Joint Res 2016;5:412-418. DOI: 10.1302/2046-3758.59.BJR-2016-0032.R1.

The missing effect of human recombinant Bone Morphogenetic Proteins BMP-2 and BMP-7 in surgical treatment of aseptic forearm nonunion

INTRODUCTION

In this cohort study, the surgical revision concept of open compression plating and autologous bone grafting with and without additional application of BMP for treatment of aseptic ulna and/or radius shaft nonunion was evaluated. The purpose was to evaluate the clinical and radiological outcome, and to determine any difference in osseous healing, range of time between revision surgery and bone healing, and postoperative complications between the cohort groups.

PATIENTS AND METHODS

Between 01/2005 and 03/2015, a prospective, randomised, controlled cohort study was performed in a Level I Trauma Centre. Forty-nine patients were treated with the diagnosis of aseptic diaphyseal ulnar and/or radial shaft nonunion using compression plating and autologous bone grafting. Additional biological augmentation using BMP-2 or BMP-7 was performed in 24 patients. Clinical and radiological follow-up was performed six weeks, three and six months after revision surgery in accordance to the system by Anderson.

RESULTS

The study group consisted of 38 men and 11 women with a median age of 44 years (range 19-77). Twenty-four out of 49 patients obtained compression plating either with autologous iliac crest bone grafting (11/24 patients) or cancellous bone grafting (13/24 patients) and additional application of BMP-2 (4/24 patients) or BMP-7 (20/24 patients). The remaining 25 patients did not receive any additional application of BMP, but autologous bone grafting. The median follow-up was 15 months (range 6-54 months). Forty-six out of 49 nonunion healed within 12 months after revision surgery with a median time to union of six months. The clinical outcome, as assessed using the system by Anderson, as well as osseous healing, duration of time interval between revision surgery and bone healing, and postoperative complications did not demonstrate significant differences between the cohort groups.

DISCUSSION

Atrophic/oligotrophic forearm nonunion healed irrespective of additional application of BMP combined with autologous bone grafting. For successful treatment, radical resection of fibrous nonunion tissue and internal compression plate fixation is required with the aim of achieving high degree of rigid stability. Also, correction of angular deformities, restoration of length, and precise axial alignment of the distal radio-ulnar joint are mandatory prerequisites to successfully achieve bone healing.