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.

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.

Technical and clinical feasibility of contrast-enhanced ultrasound evaluation of long bone non-infected nonunion healing.

PURPOSE: To assess the technical feasibility of contrast-enhanced ultrasound (CEUS) in the monitoring of non-infected long bone nonunion healing. METHODS: Twenty-five patients (16 males; mean age: 40.4 ± 11.7) with long bone nonunion were treated using surgery and mesenchymal stem cells and platelet-rich plasma. They performed CEUS up to 15 days before, 7 days, 4 and 8 weeks after treatment. To categorize the angiogenesis around the fracture site, the microvascular blood flow from CEUS was classified into four categories, depending on the portion of the investigated area that was involved in the neovascularization process: grade 0 = 0%; grade 1 = 0-30%; grade 2 = 30-70%; grade 3 = 70-100%. Nonparametric Friedman and Wilcoxon statistics were used. RESULTS: Before treatment, neovascularization was graded as 0 in 15/25 patients, as 1 in 10/25. Vascularity significantly increased over time (P < 0.001), namely: 1 (25th-75th percentile = 1-2) at 7 days; 2 (1-2) at 4 weeks; 3 (0-2) at 8 weeks. All patients but one showed early progressive increase in neovascularization well identified with CEUS at the fracture site. CONCLUSION: CEUS is a feasible method to monitor healing in patients with long bone nonunion.

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.

[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.

Hypoxia and Reactive Oxygen Species Homeostasis in Mesenchymal Progenitor Cells Define a Molecular Mechanism for Fracture Nonunion.

Fracture nonunion is a major complication of bone fracture regeneration and repair. The molecular mechanisms that result in fracture nonunion appearance are not fully determined. We hypothesized that fracture nonunion results from the failure of hypoxia and hematoma, the primary signals in response to bone injury, to trigger Bmp2 expression by mesenchymal progenitor cells (MSCs). Using a model of nonstabilized fracture healing in transgenic 5'Bmp2BAC mice we determined that Bmp2 expression appears in close association with hypoxic tissue and hematoma during the early phases of fracture healing. In addition, BMP2 expression is induced when human periosteum explants are exposed to hypoxia ex vivo. Transient interference of hypoxia signaling in vivo with PX-12, a thioredoxin inhibitor, results in reduced Bmp2 expression, impaired fracture callus formation and atrophic-like nonunion by a HIF-1α independent mechanism. In isolated human periosteum-derived MSCs, BMP2 expression could be induced with the addition of platelets concentrate lysate but not with hypoxia treatment, confirming HIF-1α-independent BMP2 expression. Interestingly, in isolated human periosteum-derived mesenchymal progenitor cells, inhibition of BMP2 expression by PX-12 is accomplished only under hypoxic conditions seemingly through dis-regulation of reactive oxygen species (ROS) levels. In conclusion, we provide evidence of a molecular mechanism of hypoxia-dependent BMP2 expression in MSCs where interference with ROS homeostasis specifies fracture nonunion-like appearance in vivo through inhibition of Bmp2 expression. Stem Cells 2016;34:2342-2353.

BMP-2-coated mineral coated microparticles improve bone repair in atrophic non-unions.

Atrophic non-unions are a major clinical problem. Mineral coated microparticles (MCM) are electrolyte-coated hydroxyapatite particles that have been shown in vitro to bind growth factors electrostatically and enable a tuneable sustained release. Herein, we studied whether MCM can be used in vivo to apply Bone Morphogenetic Protein-2 (BMP-2) to improve bone repair of atrophic non-unions. For this purpose, atrophic non-unions were induced in femurs of CD-1 mice (n = 48). Animals either received BMP-2-coated MCM (MCM + BMP; n = 16), uncoated MCM (MCM; n = 16) or no MCM (NONE; n = 16). Bone healing was evaluated 2 and 10 weeks postoperatively by micro-computed tomographic (µCT), biomechanical, histomorphometric and immunohistochemical analyses. µCT revealed more bone volume with more highly mineralised bone in MCM + BMP femurs. Femurs of MCM + BMP animals showed a significantly higher bending stiffness compared to other groups. Histomorphometry further demonstrated that the callus of MCM + BMP femurs was larger and contained more bone and less fibrous tissue. After 10 weeks, 7 of 8 MCM + BMP femurs presented with complete osseous bridging, whereas NONE femurs exhibited a non-union rate of 100 %. Of interest, immunohistochemistry could not detect macrophages within the callus, indicating a good biocompatibility of MCM. In conclusion, the local application of BMP-2-coated MCM improved bone healing in a challenging murine non-union model and, thus, should be of clinical interest in the treatment of non-unions.

Delayed Fracture Healing in Diabetics with Distal Radius Fractures.

PURPOSE OF THE STUDY Diabetics may have an increased fracture risk, depending on disease duration, quality of metabolic adjustment and extent of comorbidities, and on an increased tendency to fall. The aim of this retrospective one-centre study consisted in detecting differences in fracture healing between patients with and without diabetes mellitus. Data of patients with the most common fracture among older patients were analyzed. MATERIAL AND METHODS Classification of distal radius fractures was established according to the AO classification. Inital assessment and followup were made by conventional x-rays with radiological default settings. To evaluate fracture healing, formation of callus and sclerotic border, assessment of the fracture gap, and evidence of consolidation signs were used. RESULTS The authors demonstrated that fracture morphology does not influence fracture healing regarding time span, neither concerning consolidation signs nor in fracture gap behavior. However, tendency for bone remodeling is around 70% lower in investigated diabetics than in non-diabetics, while probability for a successful fracture consolidation is 60% lower. CONCLUSIONS To corroborate the authors hypothesis of delayed fracture healing in patients with diabetes mellitus, prospective studies incorporating influencing factors like duration of metabolic disease, quality of diabetes control, medical diabetes treatment, comorbidities and secondary diseaseas, like chronic nephropathy and osteoporosis, have to be carried out. Key words: diabetes, delayed fracture healing, distal radius fractures, callus formation, blood glucose level, osteoblasts.

Biomarkers of inflammation and innate immunity in atrophic nonunion fracture.

BACKGROUND: Nonunion is a failure of healing following a bone fracture. Its physiopathology remains partially unclear and the discovery of new mediators could promote the understanding of bone healing. METHODS: Thirty-three atrophic nonunion (NU) patients that failed to demonstrate any radiographic improvement for 6 consecutive months were recruited for providing serum samples. Thirty-five healthy volunteers (HV) served as the control group. Proteomics studies were performed using SELDI-TOF-MS and 2D-DIGE approaches, associated or not with Proteominer® preprocessing, to highlight biomarkers specific to atrophic nonunion pathology. Peak intensities were analyzed by two statistical approaches, a nonparametric Mann-Whitney U tests (univariate approach) and a machine-learning algorithm called extra-trees (multivariate approach). Validation of highlighted biomarkers was performed by alternative approaches such as microfluidic LC-MS/MS, nephelometry, western blotting or ELISA assays. RESULTS: From the 35 HV and 33 NU crude serum samples and Proteominer® eluates, 136 spectra were collected by SELDI-TOF-MS using CM10 and IMAC-Cu(2+) ProteinChip arrays, and 665 peaks were integrated for extra-trees multivariate analysis. Accordingly, seven biomarkers and several variants were identified as potential NU biomarkers. Their levels of expression were found to be down- or up-regulated in serum of HV vs NU. These biomarkers are inter-α-trypsin inhibitor H4, hepcidin, S100A8, S100A9, glycated hemoglobin ß subunit, PACAP related peptide, complement C3 α-chain. 2D-DIGE experiment allowed to detect 14 biomarkers as being down- or up-regulated in serum of HV vs NU including a cleaved fragment of apolipoprotein A-IV, apolipoprotein E, complement C3 and C6. Several biomarkers such as hepcidin, complement C6, S100A9, apolipoprotein E, complement C3 and C4 were confirmed by an alternative approach as being up-regulated in serum of NU patients compared to HV controls. CONCLUSION: Two proteomics approaches were used to identify new biomarkers up- or down-regulated in the nonunion pathology, which are involved in bone turn-over, inflammation, innate immunity, glycation and lipid metabolisms. High expression of hepcidin or S100A8/S100A9 by myeloid cells and the presence of advanced glycation end products and complement factors could be the result of a longstanding inflammatory process. Blocking macrophage activation and/or TLR4 receptor could accelerate healing of fractured bone in at-risk patients.

Predicting delayed union in osteoporotic vertebral fractures with consecutive magnetic resonance imaging in the acute phase: a multicenter cohort study.

This study demonstrated the predictive values of radiological findings for delayed union after osteoporotic vertebral fractures (OVFs). High-signal changes on T2WI were useful findings. INTRODUCTION: The purpose of the present study is to determine predictive radiological findings for delayed union by magnetic resonance imaging (MRI) and plain X-rays at two time points in the acute phase of OVFs. METHODS: This multicenter cohort study was performed from 2012 to 2015. A total of 218 consecutive patients with OVFs ≤2 weeks old were enrolled. MRIs and plain X-rays were performed at the time of enrollment and at 1- and 6-month follow-ups. Signal changes on T1-weighted imaging (T1WI) were classified as diffuse low-, confined low-, or no-signal change; those on T2WI were classified as high (similar to the intensity of cerebrospinal fluid), confined low-, diffuse low-, or no-signal change. The angular motion of the fractured vertebral body was measured with X-rays. RESULTS: A total of 153 patients completed the 6-month follow-up. A high-signal change on T2WI was most useful in predicting delayed union. Sensitivity, specificity, and positive predictive values were 53.3, 87.8, and 51.6 % at enrollment and 65.5, 84.8, and 51.4 % at the 1-month follow-up, respectively. The positive predictive value increased to 62.5 % with observation of high- or diffuse low-signal changes at both enrollment and the 1-month follow-up. The cutoff value of vertebral motion was 5 degrees. Sensitivity and specificity at enrollment were 52.4 and 74.1 %, respectively. CONCLUSIONS: This study demonstrated the radiological factors predicting delayed union after an OVF. T2 high-signal changes showed the strongest association with delayed union. Consecutive MRIs were particularly useful as a differential tool to predict delayed union following OVFs.

Bone morphogenetic protein 2 and decorin expression in old fracture fragments and surrounding tissues.

Bone morphogenetic protein 2 (BMP-2) can promote fracture healing. Although the complex role BMP-2 in bone formation is increasingly understood, the role of endogenous BMP-2 in nonunion remains unclear. Decorin (DCN) can promote the formation of bone matrix and calcium deposition to control bone morphogenesis. In this study, tissue composition and expression of BMP-2 and DCN were detected in different parts of old fracture zones to explore inherent anti-fibrotic ability and osteogenesis. Twenty-three patients were selected, including eight cases of delayed union and 15 cases of nonunion. Average duration of delayed union or nonunion was 15 months. Fracture fragments and surrounding tissues, including bone grafts, marrow cavity contents, and sticking scars, were categorically sampled during surgery. Through observation and histological testing, component comparisons were made between fracture fragments and surrounding tissue. The expression levels of DCN and BMP-2 in different tissues were detected by immunohistochemical staining and real-time polymerase chain reaction. The expression of DCN and BMP- 2 in different parts of the nonunion area showed that, compared with bone graft and marrow cavity contents, sticking scars had the highest expression of BMP-2. Compared with the marrow cavity contents and sticking scars, bone grafts had the highest expression of DCN. The low antifibrotic and osteogenic activity of the nonunion area was associated with non-co-expression of BMP-2 and DCN. Therefore, the co-injection of osteogenic factor BMP and DCN into the nonunion area can improve the induction of bone formation and enhance the conversion of the old scar, thereby achieving better nonunion treatment.

Effect of VEGF-A165 addition on the integration of a cortical allograft in a tibial segmental defect in rabbits.

PURPOSE: Long-bone segmental defects caused by infection, fracture, or tumour are a challenge for orthopaedic surgeons. Structural allografts are sometimes used in their treatment but their poor biological characteristics are a liability. The objective of this study was to determine whether the addition of recombinant vascular endothelial growth factor-A (VEGF) to a structural allograft improved its integration into a rabbit tibial segmental defect in a non-union model. METHODS: Tibial segmental defects were filled with heat sterilized allogenic tubular tibiae sections and then stabilized with a screw plate. In the VEGF treatment group (n = 6 tibiae), 2 µg of VEGF added to a 50 µl matrigel solution was inserted into the allograft cavity. In the control group (n = 6 tibiae), only matrigel was added. After 12 weeks, macroscopic and microscopic analysis, radiographs, and computerized micro-tomography (micro-CT) were performed. If allograft consolidation was present, a torsional resistance analysis was performed. RESULTS: Addition of VEGF to the allograft decreased the rate of osteosynthesis failure compared with the control group (1/6 vs. 5/6, p = 0.08), increased trabecular continuity evaluated by micro-CT in the bone-allograft interphases (8/12 vs. 2/12, p = 0.036) and histological trabecular continuity (7/12 vs. 0/12, p = 0.0046). Full consolidation was observed in three tibiae of the VEGF group and one in the control group (differences not significant); however, torsional resistance showed no significant differences (n.s.). CONCLUSION: Addition of VEGF to a structural allograph inserted into a rabbit tibial segmental defect increased allograft integration rate. Further research in this direction might help clinicians in dealing with large bone defects.

Distal scaphoid resection for degenerative arthritis secondary to scaphoid nonunion: a 20-year experience.

PURPOSE: To evaluate the long-term results of distal scaphoid excision for degenerative arthritis secondary to scaphoid nonunion and compare them with our original results published in 1999. METHODS: Nineteen patients who were treated by distal scaphoid resection arthroplasty from 1987 through 2010 were included. The mean follow-up was 15 years (range, 10-25 y) vs 4 years in the previous study. Clinical evaluation included measurement of the visual analog pain scale, wrist range of motion, and grip strength. Radiographs were taken at follow-up to assess for signs of arthritis and wrist collapse. RESULTS: The outcomes of this procedure include increased grip strength and total arc of motion, a small decrease in revised carpal height ratio, and a small increase in radiolunate angle. Two patients failed distal scaphoid resection arthroplasty necessitating proximal row carpectomy (1) and wrist arthrodesis (1) for recalcitrant pain. More than half of the remaining patients developed midcarpal arthritis on radiographs that was asymptomatic. No patients developed radiolunate arthritis. CONCLUSIONS: This study showed that distal scaphoid resection arthroplasty produced favorable, long-term clinical results and did not result in noteworthy wrist collapse. Midcarpal arthritis, which may develop after the procedure, did not cause appreciable deterioration in patient outcomes. This procedure also did not eliminate the option of using additional, more conventional reconstructive procedures if needed. TYPE OF STUDY/LEVEL OF EVIDENCE: Therapeutic IV.

[Detritic synovitis and rare skeletal diseases]. / Detritussynovialitis und seltene Skeletterkrankungen.

Detritic synovitis represents a common finding in routine orthopedic pathology. Microscopically, the synovium displays cartilaginous and bony fragments in the synoviocyte layer or within the subsynovial soft tissues associated with resorptive changes. In the vast majority of cases, detritic synovitis is associated with conditions leading to the destruction of articular cartilage and subchondral bone, such as severe osteoarthritis, collapsed avascular necrosis, diabetes mellitus, Charcot arthropathy or non-union fractures. The objective of this article is to review the literature regarding the microscopic findings in ochronosis, rapidly destructive hip disease and apatite crystal depositions that can enable a confident diagnosis or a limited differential diagnosis of detritic synovitis.

Shoulder motion, strength, and functional outcomes in children with established malunion of the clavicle.

BACKGROUND: Recent investigations of displaced clavicle fractures in adults have demonstrated a higher prevalence of nonunion, symptomatic malunion, diminished functional outcome, and decreased strength with nonoperative treatment. Although these data have led to increased surgical management of displaced fractures, little published information is available regarding the consequences of malunion in the pediatric population. The purpose of this investigation was to assess pain, functional outcome, range of motion, and strength in children with displaced clavicle fractures treated nonoperatively. METHODS: Clinical evaluation of 16 patients with mid-diaphyseal clavicle fractures and >2 cm of initial displacement was performed; all had undergone nonoperative treatment and went on to radiographic malunion. The mean age at the time of injury was 12.2±3.3 years. Pain, aesthetic appearance, and satisfaction with treatment were rated by patients on a visual analog scale (VAS) (range 0 to 10 with 10 indicating the worst score). Patient-based outcomes were assessed with the Disabilities of the Arm, Shoulder, and Hand (DASH) questionnaire and the Pediatric Outcomes Data Collection Instrument (PODCI). Bilateral shoulder motion was measured by a physical therapist. Isokinetic strength testing of the bilateral shoulders was performed with a Biodex dynometer. Range of motion and strength were analyzed with a multivariable regression, controlling for hand dominance. The mean follow-up was 27.2 months after injury. RESULTS: All displaced fractures treated nonoperatively achieved union. Overall, there was reduced forward flexion and abduction on the injured side compared with the contralateral sides of 7.3 and 6.5 degrees, respectively, adjusted for hand dominance (P<0.05). Biodex testing did not detect any significant difference in abduction or adduction torque or power between affected and unaffected shoulders. The mean VAS score for pain was 1.6, with 4 patients reporting pain ≥to 3. The mean VAS scores for satisfaction with aesthetic appearance was 2.7, with 4 patients reporting scores >5. The mean VAS scores for satisfaction with treatment was 2.0, with only 1 patient scoring >5. The mean DASH score was 4.9±7.5, with 3 patients scoring ≥10. The mean scores on the DASH sports and performing arts module was 1.9±4.2, with only 1 patient scoring ≥10. The mean global PODCI score was 94.5±6.0. The mean PODCI scores for upper extremity function, sports, and pain were 97.9±5.5, 95.4±5.3, and 84.6±20.5, respectively. Only 1 patient was symptomatic enough to require corrective osteotomy. CONCLUSIONS: Skeletally immature patients with established clavicle fracture malunions do not develop clinically meaningful loss of shoulder motion or abduction/adduction strength. Routine surgical fixation for displaced, nonsegmental clavicle fractures may not be justified based upon concerns regarding shoulder motion and strength alone. Further investigation is required to determine the risk factors and causes of pain and functional compromise in the minority of pediatric patients with symptomatic malunions. LEVEL OF EVIDENCE: Level IV.

Three key factors affecting treatment results of low-intensity pulsed ultrasound for delayed unions and nonunions: instability, gap size, and atrophic nonunion.

BACKGROUND: If some predictable factors that affect the treatment results of low-intensity pulsed ultrasound (LIPUS) for delayed union or nonunion could be determined, these might provide us with suggestions for whether LIPUS should be used as an alternative treatment for surgery or an adjuvant therapy after surgery. Therefore, the objective of the present study was to determine what factors affected failure of fracture healing after LIPUS for delayed unions and nonunions. METHODS: A one-year observational retrospective cohort study was conducted with a consecutive cohort of 101 delayed unions and 50 nonunions after long bone fractures that were treated with LIPUS between May 1998 and April 2007. The main outcome measure was radiographic determination of osseous bone union status within one year after start of LIPUS therapy. Statistical evaluation was used to recognize predictable factors that affect treatment results of LIPUS for delayed union and nonunion. RESULTS: Delayed union group (n = 101): Seventy-five delayed unions (74.3%) united without an additional major surgical intervention. Failure of LIPUS therapy was associated with types of nonunion (atrophic/oligotrophic vs. hypertrophic, relative risk 23.72 [95% CI 1.20-11.5], p < 0.01), instability at fracture site (unstable vs. stable, relative risk 3.03 [95% CI 1.67-5.49], p < 0.001), and maximum fracture gap size not less than 9 mm (relative risk 3.30 [95% CI 1.68-6.45]). Nonunion group (n = 50): Thirty-four nonunions (68.0%) united without an additional major surgical intervention. Failure of LIPUS therapy was associated with method of fixation (intramedullary nail vs. others, relative risk 4.50 [95% CI 1.69-12.00], p < 0.001), instability at fracture site (unstable vs. stable, relative risk 4.56 [95% CI 2.20-9.43], p < 0.0001), and maximum fracture gap size not less than 8 mm (relative risk 5.09 [95 % CI 1.65-15.67]). CONCLUSIONS: LIPUS should be applied as an adjuvant therapy in combination with surgical intervention for an established atrophic nonunion with instability and/or with larger fracture gap.

Smoking as a predictor of negative outcome in diaphyseal fracture healing.

PURPOSE: The purpose of this study was to evaluate the impact of tobacco abuse in the consolidation of fractures. METHODS: We retrospectively identified all patients with a diaphyseal fracture (femur, tibia, or humerus), between January 1999 and December 2010, in our orthopaedic trauma registry (Erasme hospital, Brussels, Belgium). Thirty-eight diaphyseal nonunions (ten femurs, 16 tibias and 12 humerus) were identified. Each nonunion was paired (on age, sex and location) with two control-healed fractures (76 control patients). The chi-squared test and a binary logistic regression were used for statistical analysis. RESULTS: In multivariate analysis, smoking (tobacco use) was significantly associated with nonunion, whether the fracture was open or closed (p < 0.01). In univariate analysis, open fracture was associated with a higher risk of nonunion (p < 0.05), while external fixation was associated with better bone healing (p < 0.05). CONCLUSION: Tobacco is confirmed as a deleterious factor for diaphyseal bone healing.

The treatment of segmental bone defects in rabbit tibiae with vascular endothelial growth factor (VEGF)-loaded gelatin/hydroxyapatite "cryogel" scaffold.

The aim of this study was to investigate the effectiveness of a novel hydroxyapatite containing gelatin scaffold--with and without local vascular endothelial growth factor (VEGF) administration--as the synthetic graft material in treatment of critical-sized bone defects. An experimental nonunion model was established by creating critical-sized (10 mm. in length) bone defects in the proximal tibiae of 30 skeletally mature New Zealand white rabbits. Following tibial intramedullary fixation, the rabbits were grouped into three: The defects were left empty in the first (control) group, the defects were grafted with synthetic scaffolds in the second group, and synthetic scaffolds loaded with VEGF were administered at bone defects in the third group. Five rabbits in each group were killed on 6th and 12th weeks, and new bone growth was assessed radiologically, histologically and with dual-energy X-ray absorptiometry (DEXA). At 6 weeks, VEGF-administered group had significantly better scores than the other two groups. The second group also had significantly better scores than the control group. At 12 weeks, while no significant difference was noted between the second and third groups, these two groups both had significantly better scores in all criteria compared with the control group. There were no signs of complete fracture healing in the control group. The administration of hydroxyapatite containing gelatin scaffold yielded favorable results in grafting the critical-sized bone defects in this experimental model. The local administration of VEGF on the graft had a positive effect in the early phase of fracture healing.

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.

Scapholunate advanced collapse and scaphoid nonunion advanced collapse: MDCT arthrography features.

OBJECTIVE: The aim of this article is to present the imaging features of scapholunate advanced collapse (SLAC) and scaphoid nonunion advanced collapse (SNAC) on MDCT arthrography. CONCLUSION: MDCT arthrography is an excellent tool for patients with clinically suspected SLAC or SNAC wrist because it allows identification of the spectrum of findings for diagnosis and proper classification, which directly impact management.