The promotive role of USP1 inhibition in coordinating osteogenic differentiation and fracture healing during nonunion.

BACKGROUND: Nonunion is a failure of fracture healing and a major complication after fractures. Ubiquitin-specific protease 1 (USP1) is a deubiquitinase that involved in cell differentiation and cell response to DNA damage. Herein we investigated the expression, function and mechanism of USP1 in nonunion. METHODS AND RESULTS: Clinical samples were used to detect the USP1 expression in nonunion. ML323 was selected to inhibit USP1 expression throughout the study. Rat models and mouse embryonic osteoblasts cells (MC3T3-E1) were used to investigate the effects of USP1 inhibition on fracture healing and osteogenesis in vivo and in vitro, respectively. Histological changes were examined by micro-computerized tomography (Micro-CT), hematoxylin & eosin (H&E) staining and Masson staining. Alkaline phosphatase (ALP) activity detection and alizarin red staining were used for osteogenic differentiation observation. The expression of related factors was detected by quantitative real-time PCR, western blot or immunohistochemistry (IHC). It was shown that USP1 was highly expressed in nonunion patients and nonunion rats. USP1 inhibition by ML323 promoted fracture healing in nonunion rats and facilitated the expression of osteogenesis-related factors and the signaling of PI3K/Akt pathway. In addition, USP1 inhibition accelerated osteogenic differentiation and promoting PI3K/Akt signaling in MC3T3-E1 cells. CONCLUSIONS: USP1 inhibition plays a promotive role in coordinating osteogenic differentiation and fracture healing during nonunion. PI3K/Akt may be the downstream pathway of USP1.

Percutaneous injection of platelet-rich plasma to treat atrophic nonunion after internal fixation of ulnar fracture: a case report.

Non-union is a serious postoperative complication of fracture. Early detection and intervention can avoid revision surgery. Platelet-rich plasma releases many active tissue factors and has potential to promote fracture healing. Percutaneous injection of platelet-rich plasma at the fracture site may avoid surgical treatment when non-union occurs. We present a case of atrophic non-union of an ulna fracture treated conservatively with percutaneous injection of platelet-rich plasma.

Double trapezia sign: A new radiologic sign of scaphoid nonunion.

In scaphoid nonunion, pseudarthrosis and sclerotic change occur at the nonunion site. These changes make a distal fragment look like a trapezium on plain radiographs and we called this phenomenon the double trapezia sign. The purpose of this study was to estimate the diagnostic reliability of the double trapezia sign and its clinical and prognostic implications for the scaphoid nonunion.A retrospective review of 124 patients who underwent surgical treatment because of scaphoid nonunion between January 2007 and December 2017 was performed. Two hand surgeons and 1 musculoskeletal radiologist reviewed preoperative plain radiographs independently. Each observer evaluated the plain radiographs in 2 separate sessions at least 3 weeks apart to assess intraobserver and interobserver reliabilities of the double trapezia sign. To assess clinical and prognostic implications of the double trapezia sign, the patients were divided into the positive and nonpositive groups, and several variables such as age, sex, duration of nonunion, size of the distal fragment, avascular necrosis (AVN) of the proximal fragment, type of bone graft, healing time, and failure rate were compared between the 2 groups.The kappa values of intraobserver and interobserver reliabilities were >0.8, corresponding to almost perfect agreement. There were 58 patients in the positive group and 66 patients in the nonpositive group. The mean duration of nonunion was 38.5 months in the positive group and 12.2 months in the nonpositive group (P < .001). The size of distal fragment was 49.6% and 60.9%, respectively (P < .001). The AVN of proximal fragment was 24.1% and 54.5%, respectively (P = .001). The mean healing time was 4.1 and 6.4 months, respectively (P < .001). The failure rate was 13.8% and 27.3%, respectively (P = .066).In conclusion, the double trapezia sign is a valuable radiographic sign of scaphoid nonunion. The double trapezia sign is easily identifiable on plain radiographs and has excellent intra- and interobserver reliabilities. The positive double trapezia sign implies mid-waist nonunion, long duration of nonunion, less possibility of AVN, and favorable postoperative prognosis.

Acute correction and intramedullary nailing of aseptic oligotrophic and atrophic tibial nonunions with deformity.

OBJECTIVES: This study aims to describe the important points for treatment of aseptic tibial oligotrophic and atrophic nonunions by intramedullary nailing (IMN). PATIENTS AND METHODS: The retrospective study included 17 biologically nonactive nonunion patients (12 males, 5 females; mean age 36.4 years; range, 19 to 49 years) operated between February 2010 and November 2017 by deformity correction, static IMN and autografting. The mean follow-up time was 4.2 (range, 3 to 7) years. The initial fracture management was external fixator for all patients. Fourteen patients had open fractures initially. Six patients had valgus, four patients had varus, three patients had oblique plane, and four patients had external rotational deformity. Nonunion diagnosis was established on the basis of the patient history and physical examination based on plain radiographs, computed tomography or both. All patients were evaluated by the same protocol to exclude any infection. RESULTS: The median time from injury to nailing was mean 10.3 (range, 6.1 to 36.5) months. Radiologic and clinical union was achieved in all patients. The mean union time was 3.64 (range, 3 to 6) months. Three patients had positive intraoperative bacteriological culture. In four patients, dynamization was necessary for consolidation. Late deep infection developed in three patients after union, and all infected cases were operated by implant removal, debridement, and appropriate antibiotics. CONCLUSION: Intramedullary nailing and autografting after external fixator provide good results for the treatment of aseptic biologically nonactive nonunions with deformity. Reamed IMN ensures sufficient deformity correction, biological environment, and mechanical stability. The infection risk should always be kept in mind and patients should be followed-up closely to prevent complications.

The neurofibromatosis type I gene promotes autophagy via mTORC1 signalling pathway to enhance new bone formation after fracture.

Bone fracture is one of the most common injuries. Despite the high regenerative capacity of bones, failure of healing still occurs to near 10% of the patients. Herein, we aim to investigate the modulatory role of neurofibromatosis type I gene (NF1) to osteogenic differentiation of bone marrow-derived mesenchymal stem cells (BMSCs) and new bone formation after fracture in a rat model. We studied the NF1 gene expression in normal and non-union bone fracture models. Then, we evaluated how NF1 overexpression modulated osteogenic differentiation of BMSCs, autophagy activity, mTORC1 signalling and osteoclastic bone resorption by qRT-PCR, Western blot and immunostaining assays. Finally, we injected lentivirus-NF1 (Lv-NF1) to rat non-union bone fracture model and analysed the bone formation process. The NF1 gene expression was significantly down-regulated in non-union bone fracture group, indicating NF1 is critical in bone healing process. In the NF1 overexpressing BMSCs, autophagy activity and osteogenic differentiation were significantly enhanced. Meanwhile, the NF1 overexpression inhibited mTORC1 signalling and osteoclastic bone resorption. In rat non-union bone fracture model, the NF1 overexpression significantly promoted bone formation during fracture healing. In summary, we proved the NF1 gene is critical in non-union bone healing, and NF1 overexpression promoted new bone formation after fracture by enhancing autophagy and inhibiting mTORC1 signalling. Our results may provide a novel therapeutic clue of promoting bone fracture healing.

Value of SPECT/CT in the assessment of necrotic bone fragments in patients with delayed bone healing or non-union after traumatic fractures.

OBJECTIVE: To evaluate the value of single-photon emission computed tomography / computed tomography (SPECT/CT) compared with planar bone scintigraphy (BS) in the assessment of necrotic bone fragments in patients with delayed bone healing or non-union after traumatic fractures. METHODS: Retrospective evaluation of patients with traumatic fractures and suspected delayed healing or non-union and/or persistent pain or suspected infection who had undergone planar late phase BS and SPECT/CT between 2011 and 2018. On the BS and SPECT/CT images, a necrotic fragment was considered if there was an area of absent radiotracer uptake (photopenia) related to bone at the fracture site. Histology served as a reference standard (presence or absence of necrotic bone fragments). If histology was not available, intraoperative findings and combined clinical and imaging follow-up served as reference standards. RESULTS: In 37 consecutive patients with traumatic fractures (femur (n = 18), tibia (11), humerus (6), radius (1), jaw (1)), necrotic bone fragments were suspected in 11 fractures (29.7%) on BS and in 16 fractures (43.2%) on SPECT/CT. 35 fractures (94.6%) had metallic implants. Histology showed necrotic fragments in 10/11 (90.9%) patients. For the detection of necrotic bone fragments, SPECT/CT showed sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of 100%, 95%, 94%, 100%, and 97%, respectively, and BS 67%, 95%, 91%, 81%, and 83%, respectively. SPECT/CT significantly outperformed BS with better area under curve (AUC) for SPECT/CT (0.9773) compared to planar imaging (0.8106) (p-value < 0.01). CONCLUSIONS: SPECT/CT is an accurate tool in the assessment of necrotic bone fragments in patients with delayed bone healing or non-union after traumatic bone fractures and is superior to conventional planar BS. ADVANCES IN KNOWLEDGE: SPECT/CT is accurate and superior to planar BS in identification of necrotic bone fragments, responsible for delayed bone healing/non-union after fractures.

NSM00158 Specifically Disrupts the CtBP2-p300 Interaction to Reverse CtBP2-Mediated Transrepression and Prevent the Occurrence of Nonunion.

Carboxyl-terminal binding proteins (CtBPs) are transcription regulators that control gene expression in multiple cellular processes. Our recent findings indicated that overexpression of CtBP2 caused the repression of multiple bone development and differentiation genes, resulting in atrophic nonunion. Therefore, disrupting the CtBP2-associated transcriptional complex with small molecules may be an effective strategy to prevent nonunion. In the present study, we developed an in vitro screening system in yeast cells to identify small molecules capable of disrupting the CtBP2-p300 interaction. Herein, we focus our studies on revealing the in vitro and in vivo effects of a small molecule NSM00158, which showed the strongest inhibition of the CtBP2-p300 interaction in vitro. Our results indicated that NSM00158 could specifically disrupt CtBP2 function and cause the disassociation of the CtBP2-p300-Runx2 complex. The impairment of this complex led to failed binding of Runx2 to its downstream targets, causing their upregulation. Using a mouse fracture model, we evaluated the in vivo effect of NSM00158 on preventing nonunion. Consistent with the in vitro results, the NSM00158 treatment resulted in the upregulation of Runx2 downstream targets. Importantly, we found that the administration of NSM00158 could prevent the occurrence of nonunion. Our results suggest that NSM00158 represents a new potential compound to prevent the occurrence of nonunion by disrupting CtBP2 function and impairing the assembly of the CtBP2-p300-Runx2 transcriptional complex.

Nandrolone decanoate in induced fracture nonunion with vascular deficit in rat model: morphological aspects.

BACKGROUND: The nonunion fracture is a relatively frequent complication in both human and veterinary medicine. Specifically, atrophic fracture nonunions are difficult to treat, with revision surgery usually providing the best prognosis. Anabolic steroids, such as nandrolone decanoate (ND), have been reported to have beneficial clinical effects on bone mass gain during osteoporosis; however, their utility in promoting regeneration in atrophic nonunions has not been documented. Our objective was to examine morphological changes induced by the ND in experimental fracture nonunion with vascular deficit in the rat model. METHODS: Fourteen adult Wistar rats had an atrophic fracture nonunion induced in the diaphysis of their left femur. Rats were allocated into two groups: control group and nandrolone decanoate group. Rats in the latter group were given nandrolone decanoate (1.5 mg/kg IM, once a week, during 4 weeks after confirmation of fracture nonunion radiographically). Radiographic and anatomopathological examination, micro-tomography and histological analysis were assessed to characterize the morphological changes promoted by the nandrolone decanoate use. RESULTS: Based on radiology, anatomopathological evaluation, computed micro-tomography and conventional microscopy, nandrolone decanoate promoted bone regeneration at the fracture nonunion site by increasing the cellularity at the fracture site. Percentage of collagen was not significantly different between groups, consistent with high-quality regenerated bone. CONCLUSION: The anabolic steroid nandrolone decanoate improved bone mass and regeneration without affecting collagen production and therefore has potential for improving outcomes for atrophic fracture nonunion.

Inflammatory processes and elevated osteoclast activity chaperon atrophic non-union establishment in a murine model.

BACKGROUND: Delayed bone healing, especially in long bones poses one of the biggest problems in orthopeadic and reconstructive surgery and causes tremendous costs every year. There is a need for exploring the causes in order to find an adequate therapy. Earlier investigations of human scaphoid non-union revealed an elevated osteoclast activity, accompanied by upregulated levels of TGF-beta and RANKL. Interestingly, scaphoid non-union seemed to be well vascularized. METHODS: In the current study, we used a murine femur-defect model to study atrophic non unions over a time-course of 10 weeks. Different time points were chosen, to gather insights into the dynamic processes of non-union establishment. RESULTS: Histological analyses as well as western blots and qRT-PCR indicated enhanced osteoclast activity throughout the observation period, paralleled by elevated levels of TGF-beta, TNF-alpha, MMP9, MMP13 and RANKL, especially during the early phases of non-union establishment. Interestingly, elevated levels of these mediators decreased markedly over a period of 10 weeks, as inflammatory reaction during non-union establishment seemed to wear out. To our surprise, osteoblastogenesis seemed to be unaffected during early stages of non-union establishment. CONCLUSION: Taken together, we gained first insights into the establishment process of atrophic non unions, in which inflammatory processes accompanied by highly elevated osteoclast activity seem to play a leading role.

Defective Proliferation and Osteogenic Potential with Altered Immunoregulatory phenotype of Native Bone marrow-Multipotential Stromal Cells in Atrophic Fracture Non-Union.

Bone marrow-Multipotential stromal cells (BM-MSCs) are increasingly used to treat complicated fracture healing e.g., non-union. Though, the quality of these autologous cells is not well characterized. We aimed to evaluate bone healing-related capacities of non-union BM-MSCs. Iliac crest-BM was aspirated from long-bone fracture patients with normal healing (U) or non-united (NU). Uncultured (native) CD271highCD45low cells or passage-zero cultured BM-MSCs were analyzed for gene expression levels, and functional assays were conducted using culture-expanded BM-MSCs. Blood samples were analyzed for serum cytokine levels. Uncultured NU-CD271highCD45low cells significantly expressed fewer transcripts of growth factor receptors, EGFR, FGFR1, and FGRF2 than U cells. Significant fewer transcripts of alkaline phosphatase (ALPL), osteocalcin (BGLAP), osteonectin (SPARC) and osteopontin (SPP1) were detected in NU-CD271highCD45low cells. Additionally, immunoregulation-related markers were differentially expressed between NU- and U-CD271highCD45low cells. Interestingly, passage-zero NU BM-MSCs showed low expression of immunosuppressive mediators. However, culture-expanded NU and U BM-MSCs exhibited comparable proliferation, osteogenesis, and immunosuppression. Serum cytokine levels were found similar for NU and U groups. Collectively, native NU-BM-MSCs seemed to have low proliferative and osteogenic capacities; therefore, enhancing their quality should be considered for regenerative therapies. Further research on distorted immunoregulatory molecules expression in BM-MSCs could potentially benefit the prediction of complicated fracture healing.

Clinical pathologies of bone fracture modelled in zebrafish.

Reduced bone quality or mineral density predict susceptibility to fracture and also attenuate subsequent repair. Bone regrowth is also compromised by bacterial infection, which exacerbates fracture site inflammation. Because of the cellular complexity of fracture repair, as well as genetic and environmental influences, there is a need for models that permit visualisation of the fracture repair process under clinically relevant conditions. To characterise the process of fracture repair in zebrafish, we employed a crush fracture of fin rays, coupled with histological and transgenic labelling of cellular responses; the results demonstrate a strong similarity to the phased response in humans. We applied our analysis to a zebrafish model of osteogenesis imperfecta (OI), which shows reduced bone quality, spontaneous fractures and propensity for non-unions. We found deficiencies in the formation of a bone callus during fracture repair in our OI model and showed that clinically employed antiresorptive bisphosphonates can reduce spontaneous fractures in OI fish and also measurably reduce fracture callus remodelling in wild-type fish. The csf1ra mutant, which has reduced osteoclast numbers, also showed reduced callus remodelling. Exposure to excessive bisphosphonate, however, disrupted callus repair. Intriguingly, neutrophils initially colonised the fracture site, but were later completely excluded. However, when fractures were infected with Staphylococcus aureus, neutrophils were retained and compromised repair. This work elevates the zebrafish bone fracture model and indicates its utility in assessing conditions of relevance to an orthopaedic setting with medium throughput.This article has an associated First Person interview with the first author of the paper.

miR-381 modulates human bone mesenchymal stromal cells (BMSCs) osteogenesis via suppressing Wnt signaling pathway during atrophic nonunion development.

The osteogenic differentiation of human bone mesenchymal stromal cells (BMSCs) has been considered as a central issue in fracture healing. Wnt signaling could promote BMSC osteogenic differentiation through inhibiting PPARγ. During atrophic nonunion, Wnt signaling-related factors, WNT5A and FZD3 proteins, were significantly reduced, along with downregulation of Runx2, ALP, and Collagen I and upregulation of PPARγ. Here, we performed a microarray analysis to identify differentially expressed miRNAs in atrophic nonunion tissues that were associated with Wnt signaling through targeting related factors. Of upregulated miRNAs, miR-381 overexpression could significantly inhibit the osteogenic differentiation in primary human BMSCs while increase in PPARγ protein level. Through binding to the 3'UTR of WNT5A and FZD3, miR-381 modulated the osteogenic differentiation via regulating ß-catenin nucleus translocation. Moreover, PPARγ, an essential transcription factor inhibiting osteogenic differentiation, could bind to the promoter region of miR-381 to activate its expression. Taken together, PPARγ-induced miR-381 upregulation inhibits the osteogenic differentiation in human BMSCs through miR-381 downstream targets, WNT5A and FZD3, and ß-catenin nucleus translocation in Wnt signaling. The in vivo study also proved that inhibition of miR-381 promoted the fracture healing. Our finding may provide a novel direction for atrophic nonunion treatment.

Non-union: Indications for external fixation.

External fixation is currently used as the definitive mode of fracture stabilisation in the management of ˜50% of long-bone non-unions. Distinction between non-union and delayed union is a diagnostic dilemma especially in fractures healing by primary bone repair. This distinction is important, as non-unions are not necessarily part of the same spectrum as delayed unions. The aetiology of a fracture non-union is usually multifactorial and the factors can be broadly categorized into mechanical factors, biological (local and systemic) factors, and infection. Infection is present in ˜40% of fracture non-unions, often after open fractures or impaired wound healing, but in 5% of all non-unions infection is present without any clinical or serological suspicion. General indications for external fixation include clinical scenarios where; 1) percutaneous correction of alignment, or mechanical stimulation of the non-union site is required; 2) fixation of juxta-articular or 'emmental' bone fragments is necessary; and 3) staged bone or soft tissue reconstruction is anticipated. Specific anatomical indications include infected non-unions of the tibia, humerus, and juxta-articular bone. External fixation is an essential tool in the management of fracture non-unions. However, with greater understanding of the outcomes associated with both external and internal fixation the relative indications are now being refined.

Treatment of atrophic nonunion via autogenous ilium grafting assisted by vertical fixation of double plates: A case series of patients.

OBJECTIVE: To investigate the efficacy of the treatment of atrophic nonunion using structural autogenous ilium bone grafting in combination with vertical fixation of double plates. METHODS: This retrospective study analysed the clinical data from consecutive patients with atrophic nonunion who underwent autogenous ilium grafting in combination with double-plate vertical fixation. The injury type and the bone affected by nonunion, the duration of nonunion and the outcomes following surgery were recorded for all patients. RESULTS: The study enrolled 43 patients with atrophic nonunion of the upper and lower limbs: 17 patients with tibial nonunion, 21 with femoral nonunion, four with humeral nonunion and one with radial shaft nonunion. The mean duration of postoperative follow-up was 14.5 months (range, 8-28 months). A total of 43 of 43 patients (100%) achieved a healed nonunion fracture without the occurrence of complications such as infection, fracture of internal fixation or pain in the harvesting site. Comprehensive postoperative assessments of bone healing and function were observed to be good and/or excellent in all 43 patients. CONCLUSION: Structural autogenous ilium grafting used in combination with double-plate vertical fixation can provide a stable structural environment for near optimal bone healing in patients with atrophic nonunion.

Periosteal Mesenchymal Progenitor Dysfunction and Extraskeletally-Derived Fibrosis Contribute to Atrophic Fracture Nonunion.

Atrophic nonunion represents an extremely challenging clinical dilemma for both physicians and fracture patients alike, but its underlying mechanisms are still largely unknown. Here, we established a mouse model that recapitulates clinical atrophic nonunion through the administration of focal radiation to the long bone midshaft 2 weeks before a closed, semistabilized, transverse fracture. Strikingly, fractures in previously irradiated bone showed no bony bridging with a 100% nonunion rate. Radiation triggered distinct repair responses, separated by the fracture line: a less robust callus formation at the proximal side (close to the knee) and bony atrophy at the distal side (close to the ankle) characterized by sustained fibrotic cells and type I collagen-rich matrix. These fibrotic cells, similar to human nonunion samples, lacked osteogenic and chondrogenic differentiation and exhibited impaired blood vessel infiltration. Mechanistically, focal radiation reduced the numbers of periosteal mesenchymal progenitors and blood vessels and blunted injury-induced proliferation of mesenchymal progenitors shortly after fracture, with greater damage particularly at the distal side. In culture, radiation drastically suppressed proliferation of periosteal mesenchymal progenitors. Radiation did not affect hypoxia-induced periosteal cell chondrogenesis but greatly reduced osteogenic differentiation. Lineage tracing using multiple reporter mouse models revealed that mesenchymal progenitors within the bone marrow or along the periosteal bone surface did not contribute to nonunion fibrosis. Therefore, we conclude that atrophic nonunion fractures are caused by severe damage to the periosteal mesenchymal progenitors and are accompanied by an extraskeletal, fibro-cellular response. In addition, we present this radiation-induced periosteal damage model as a new, clinically relevant tool to study the biologic basis of therapies for atrophic nonunion. © 2018 American Society for Bone and Mineral Research.

Reamer-Irrigator-Aspirator bone graft harvesting for treatment of segmental bone loss: analysis of defect volume as independent risk factor for failure.

INTRODUCTION: The management of segmental bone loss poses a significant clinical challenge. The purpose of this study was to conduct a retrospective evaluation of our experience in treating segmental bone loss, using Reamer-Irrigator-Aspirator (RIA)-harvested autologous bone graft. MATERIALS AND METHODS: Between June 2008 and March 2015, 81 patients were treated with the RIA technique for multiple purposes. Inclusion criteria for this study were skeletal mature patients with segmental bone loss, due to acute trauma or non-union, who were treated with RIA-harvested bone graft. Exclusion criteria were skeletal immaturity, pathological fractures and indications for the RIA system other than bone graft harvesting. The primary outcome parameter was clinical and radiographical bone healing. RESULTS: During the study period, 72 patients met the inclusion criteria. In total, 39 patients (54.2%) were classified as having clinical and radiographical bone healing. Although univariate analysis could not reveal any significant influence of specific risk factors to predict the outcome, there was a trend towards statistical significance for defect volume. Further analysis indeed revealed that smaller defect volumes (< 8 cm3) had a lower risk of non-union. CONCLUSIONS: In approximately half of our study population, the use of the RIA technique for autologous bone graft harvesting in cases of segmental bone loss resulted in a successful outcome with bone healing. Defect size seems to be a critical issue regarding the outcome. Although our results are less promising than previously published, the RIA technique has its place in the treatment algorithm of segmental bone defects.

Unusual presentation of recurrent subtrochanteric non-union in a patient with hip arthrodesis: A case report.

This case report describes the management and therapeutic solution for the treatment of subtrochanteric non-union in a patient with hip arthrodesis. Two techniques can be used in the treatment of these non-unions: a closed intramedullary nailing or an open technique with plate, preferably carried out together with cortical bone graft. The surgical technique varies depending on the fixation method used for the initial treatment of the fracture and on the characteristics of the non-union. We report an unusual case of a patient who started her long clinical history more than 40 years ago with a septic arthritis of the hip healed in arthrodesis. 35 years later, after having undergone various surgeries, she fractured the proximal femur, which had to be operated seven times before reaching healing. Satisfactory outcomes were finally obtained. Arthrodesis proved to be the main cause of failed healing and of the recurrent non-union.

[Expression of transforming growth factor 1 and bone morphogenetic protein 9 in human nonunion tissues and its clinical significance].

OBJECTIVE: To examine the expression of transforming growth factor 1(TGF-ß1) and bone morphogenetic protein-9 (BMP-9) in human nonunion tissues, and to evaluate the clinical significance.
 Methods: The number of hypertrophic nonunion tissue samples and atrophic nonunion tissue samples were collected from Department of Orthopedics, the Second Xiangya Hospital of Central South University and Suzhou Kowloon Hospital Affiliated to School of Medicine of Shanghai Jiao Tong University between 2010 and 2014. Semi-quantification of SP immunohistochemical method and pathological image analysis software IPP6.0 were used to analyze the expression of TGF-ß1 and BMP-9. Nonunion type, patients' age and nonunion time were statistical analyzed.
 Results: The absorbance values of TGF-ß1 and BMP-9 in the hypertrophic nonunion tissues were 0.3236±0.0390 and 0.1337±0.0400, respectively; while the absorbance values ofTGF-ß1 and BMP-9 in the atrophic nonunion tissues were 0.3191±0.0369 and 0.1373±0.0423, respectively, with no significant difference between the two types of tissues (both P>0.05). There was also no significant difference in patients' age and bone nonunion time between them (all P>0.05).
 Conclusion: There is no significant difference in osteogenic potential between the hypertrophic nonunion tissues and the atrophic nonunion tissues.

Correlation of CT imaging and histology to guide bone graft selection in scaphoid non-union surgery.

INTRODUCTION: For the treatment of scaphoid non-unions (SNU), different surgical techniques, including vascularized and non-vascularized bone grafts, are applied. Besides stability, vascularity, and the biological situation at the non-union site are important for healing and the appropriate choice of treatment. We assessed the healing potential of SNUs by histological parameters and compared it to CT parameters of bone structure and fracture location. Based on the results, we developed a CT classification and a treatment algorithm to impact graft selection in SNU surgery. PATIENTS AND METHODS: Preoperative 2D-CT reformations of 29 patients were analyzed for trabecular structure, sclerosis, and fragmentation of the proximal fragment. The fracture location was assessed on 3D-CT reconstructions and grouped in three zones depending on the potential blood supply. Samples were taken during surgery for histological evaluation. Histological parameters of bone healing were defined and a bone healing capacity score (BHC), reflecting histological bone viability, was calculated. CT findings were compared to BHC, age of SNU, and time to union. RESULTS: Cases with trabecular structure and without fragmentation showed a statistically significant higher BHC. Time to union was significantly faster if trabecular structure was present and sclerosis was absent. In intraarticular proximal pole non-unions, where no blood supply is assumed, the BHC was statistically significantly lower and time to union was longer compared to SNUs of the other locations. A statistically significant correlation between BHC and time to union was found in the proximal and distal fragment with higher BHC associated with faster healing. CONCLUSIONS: CT parameters of bone structure and fracture location can reflect histological healing capacity of SNUs. This can guide bone graft selection in SNU surgery.

Nonunion fracture healing: Evaluation of effectiveness of demineralized bone matrix and mesenchymal stem cells in a novel sheep bone nonunion model.

Nonunion treatment has a high rate of success, although recalcitrant nonunion may determine the need for amputation. Therefore, new treatment options are continuously investigated in order to further reduce the risk of nonunion recurrence. This study aimed to (a) develop a new large animal model for bone atrophic nonunion and (b) compare the efficacy of demineralized bone matrix (DBM) and DBM in combination with mesenchymal stem cells (MSC) in the new nonunion model. The new model consists of a noncritical, full-thickness segmental defect created in the sheep tibia, stabilized by an intramedullary nail, and involves the creation of a locally impaired blood supply achieved through periosteum excision and electrocauterization of the stump ends. Six weeks after defect creation, lack of hard tissue callus and established nonunion was observed in all operated tibiae both by radiographic and clinical evaluation. Nonunion was treated with allogeneic DBM or autologous MSC cultivated on DBM particles (DBM + MSC) for 1 day before implantation. Twelve weeks after treatment, radiographic, microtomographic, histologic, and histomorphometric analysis showed the formation of bone callus in DBM group, whereas the fracture healing appeared at an early stage in DBM + MSC group. Torsional strength and stiffness of the DBM group appeared higher than those of DBM + MSC group, although the differences were not statistically significant. In conclusion, a new sheep bone nonunion model resembling the complexity of the clinical condition was developed. DBM is an effective option for nonunion treatment, whereas MSC do not improve the healing process when cultivated on DBM particles before implantation.