Titanium versus stainless steel alloy bridge plates for distal femur fractures: Does callus form earlier with titanium?

INTRODUCTION: Distal femur fractures account for 3-6% of all femur fractures. Internal fixation of most distal femur fractures with an anatomic lateral locking plate should permit some motion at the metaphyseal portion of the fracture when secondary bone healing is planned by the operating surgeon. While several studies have been performed evaluating union rates for distal femur fractures with stainless steel and titanium plates, the timing of callus formation between stainless steel and titanium implants used as bridge plates for distal femur fractures (AO/OTA 33-A and -C) has been investigated to a lesser extent. We hypothesize that callus will be visualized earlier with post-operative radiographs with titanium versus stainless steel bridge plates. METHODS: We retrospectively reviewed a consecutive cohort of patients over 18 years of age with acute AO/OTA 33-A and 33-C fracture patterns treated with an isolated stainless steel or titanium lateral bridge plate within 4 weeks of injury by a single fellowship-trained orthopedic trauma surgeon from 2011 to 2020 at one academic Level 1 trauma center. An independent, fellowship-trained orthopedic trauma attending surgeon reviewed anterior-posterior (AP) and lateral radiographs from every available post-operative clinic visit and graded them using the Modified Radiographic Score for Tibia (mRUST). RESULTS: Twenty-five subjects were included in the study with 10 with stainless steel and 15 with titanium plates. There were no significant differences in demographics between both groups, including age, sex, BMI, injury classification, open versus closed, mechanism, and laterality. Statistically significant increased mRUST scores, indicating increased callus formation, were seen on 12-week radiographs (8.4 vs. 11.9, p = 0.02) when titanium bridge plates were used. There were no statistically significant differences in mRUST scores at 6 or 24-weeks, but scores in the titanium group were higher in at every timepoint. DISCUSSION: In conclusion, we observed greater callus formation at 12 weeks after internal fixation of 33-A and 33-C distal femur fractures treated with titanium locked lateral distal femoral bridge plates compared to stainless steel plates. Our data suggest that titanium metallurgy may have quicker callus formation compared to stainless steel if an isolated, lateral locked bridge plate is chosen for distal femur fracture fixation.

Moderate static magnetic field promotes fracture healing and regulates iron metabolism in mice.

BACKGROUND: Fractures are the most common orthopedic diseases. It is known that static magnetic fields (SMFs) can contribute to the maintenance of bone health. However, the effect and mechanism of SMFs on fracture is still unclear. This study is aim to investigate the effect of moderate static magnetic fields (MMFs) on bone structure and metabolism during fracture healing. METHODS: Eight-week-old male C57BL/6J mice were subjected to a unilateral open transverse tibial fracture, and following treatment under geomagnetic field (GMF) or MMF. The micro-computed tomography (Micro-CT) and three-point bending were employed to evaluate the microarchitecture and mechanical properties. Endochondral ossification and bone remodeling were evaluated by bone histomorphometric and serum biochemical assay. In addition, the atomic absorption spectroscopy and ELISA were utilized to examine the influence of MMF exposure on iron metabolism in mice. RESULTS: MMF exposure increased bone mineral density (BMD), bone volume per tissue volume (BV/TV), mechanical properties, and proportion of mineralized bone matrix of the callus during fracture healing. MMF exposure reduced the proportion of cartilage in the callus area during fracture healing. Meanwhile, MMF exposure increased the number of osteoblasts in callus on the 14th day, and reduced the number of osteoclasts on the 28th day of fracture healing. Furthermore, MMF exposure increased PINP and OCN levels, and reduced the TRAP-5b and ß-CTX levels in serum. It was also observed that MMF exposure reduced the iron content in the liver and callus, as well as serum ferritin levels while elevating the serum hepcidin concentration. CONCLUSIONS: MMF exposure could accelerate fracture healing via promote the endochondral ossification and bone formation while regulating systemic iron metabolism during fracture healing. This study suggests that MMF may have the potential to become a form of physical therapy for fractures.

Estrogen deficiency impedes fracture healing despite eliminating the excessive absorption of the posterior callus in a semi-fixed distal tibial fracture mouse model.

BACKGROUND: Treatment of distal tibial fractures is a challenge due to their specific anatomical location. However, there is no appropriate mouse model to simulate a clinical distal tibial fracture for basic research. The aim of this investigation was to evaluate the feasibility of simulating a clinical fracture of the distal tibia of mice and to investigate the effect of ovariectomy (OVX)-induced osteoporosis on fracture healing in this model. METHODS: Sixty female 8-week-old C57BL/6 mice were randomly divided into two groups, either sham or OVX. A semi-fixation distal tibia fracture was established in the right tibia after 8 weeks of OVX. The right tibias were collected at 7, 14, 21, and 28 days post fracture. RESULTS: In the semi-fixation distal tibia fracture model, the posterior callus in the sham group showed excessive bone resorption and lower bone mass phenotype compared with the anterior site; a similar trend was not found in the OVX group. At 28 days post fracture, the posterior callus was more mineralized than the anterior callus in the OVX group. Although the fracture healing of the sham group showed a special phenotype in this mode, the progress and quality of fracture healing were still better than those of the OVX group. CONCLUSION: A semi-fixed distal tibial closed fracture mouse model was successfully established. In this model, excess bone resorption of the posterior callus impaired normal fracture healing, but not in OVX-induced osteoporotic bone. Although the stress shielding effect was not observed in the OVX group, impaired bone healing caused by OVX was still present. Our results suggest that this fracture model may have potential for studies on distal tibial fractures and stress shielding.

Combined electric and magnetic field therapy for bone repair and regeneration: an investigation in a 3-mm and an augmented 17-mm tibia osteotomy model in sheep.

BACKGROUND: Therapies using electromagnetic field technology show evidence of enhanced bone regeneration at the fracture site, potentially preventing delayed or nonunions. METHODS: Combined electric and magnetic field (CEMF) treatment was evaluated in two standardized sheep tibia osteotomy models: a 3-mm non-critical size gap model and a 17-mm critical size defect model augmented with autologous bone grafts, both stabilized with locking compression plates. CEMF treatment was delivered across the fracture gap twice daily for 90 min, starting 4 days postoperatively (post-OP) until sacrifice (9 or 12 weeks post-OP, respectively). Control groups received no CEMF treatment. Bone healing was evaluated radiographically, morphometrically (micro-CT), biomechanically and histologically. RESULTS: In the 3-mm gap model, the CEMF group (n = 6) exhibited higher callus mineral density compared to the Control group (n = 6), two-fold higher biomechanical torsional rigidity and a histologically more advanced callus maturity (no statistically significant differences). In the 17-mm graft model, differences between the Control (n = 6) and CEMF group (n = 6) were more pronounced. The CEMF group showed a radiologically more advanced callus, a higher callus volume (p = 0.003) and a 2.6 × higher biomechanical torsional rigidity (p = 0.024), combined with a histologically more advanced callus maturity and healing. CONCLUSIONS: This study showed that CEMF therapy notably enhanced bone healing resulting in better new bone structure, callus morphology and superior biomechanical properties. This technology could transform a standard inert orthopedic implant into an active device stimulating bone tissue for accelerated healing and regeneration.

Effects of different intensities of intermittent pneumatic soft-tissue compression on bone defect repair.

BACKGROUND: To estimate the effects of different intensities of intermittent pneumatic soft-tissue compression on bone defect repair in an animal model. METHODS: Five mm radial bone defect in length was made in 64 mature New Zealand rabbits and all animals randomly assigned into four groups: Group A (control group without compression), Group B (5-7 kPa intensity), Group C (8-10 kPa intensity) and Group D (11-13 kPa intensity). On the fourth day after surgery, their legs were intermittently pneumatic compressed for 4 weeks. The stimulation lasted 30 min every day and the frequency of compression was 15 Hz. New bone formation in 4 groups was evaluated by gross observation, X-ray, Micro-CT, and histological staining at 2 and 4 weeks after surgery. RESULT: There was more new bony callus in the bone defect in group C than in other groups by gross observation and X-ray radiography at 2 and 4 weeks. The Micro-CT results showed more new bony callus, bone trabecula and higher bone mineral density in group C. Fluorescent labeling results showed the speed of new bone formation in Group C was faster than that in other groups, among which the control group had the slowest speed of new bone formation. The result of histology had shown that the trabeculae in bone callus in group C had a regular form, the trabeculae were wide and had a more become osteoblast around them. CONCLUSION: The intermittent pneumatic soft-tissue compression can accelerate new bone formation of bone defects and the optimal intensity is 8-10 kPa for repairing the rabbit radial bone defect.

Tetracalcium phosphate treatment on experimental fracture model in rats.

OBJECTIVES: This study aims to investigate the efficacy of tetracalcium phosphate (TTCP) on fracture healing in rat femurs. MATERIALS AND METHODS: Forty-two female Wistar Albino rats were randomized into two groups (Group 1 and Group 2, n=21 for each). The left femur of all animals was fractured by osteotomy after deep anesthesia with ketamine. Additional procedure was not applied to the rats in Group 1. Rats in Group 2, following osteotomy, were applied to the fracture line approximately 2 mL TTCP. The animals were sacrificed at Weeks 1, 2, and 3 after surgery (seven animals were sacrificed from each group each week) and the broken femurs were removed. The femurs were examined first radiographically and second histopathologically. RESULTS: Radiologically, callus maturity and bone union increased with time in both groups. However, no significant differences were found regarding callus maturity and bone union in weekly comparisons (anteroposterior plain: p=0.53, p=0.37, p=0.42, lateral plain: p=0.26, p=0.42, p=0.87). Histopathologically, the fractures healed normally as the weeks progressed in both groups. The histological scores of Group 2 were higher at Weeks 1, 2, and 3. In the evaluation, no significant difference was found between the groups in terms of histological scores except for the first week (p=0.024, p=104, p=462, respectively). CONCLUSION: Although there was no statistically significant difference in the histological evaluation of both groups, except for the first week, the histological scores of Group 2, which underwent TTCP in all weeks, were higher. According to the results of this study, we believe that TTCP may be beneficial, particularly in the early stages of fracture healing.

Optimal timing for intermittent administration of parathyroid hormone (1-34) for distraction osteogenesis in rabbits.

BACKGROUND: To date, the usefulness of parathyroid hormone [PTH (1-34)] in distraction osteogenesis has been reported in several studies. We aimed to determine the optimal timing of PTH (1-34) administration in a rabbit distraction osteogenesis model. METHODS: The lower hind leg of a Japanese white rabbit was externally fixed, and tibial osteotomy was performed. One week after the osteotomy, bone lengthening was carried out at 0.375 mm/12 h for 2 weeks. After 5 weeks, the lower leg bone was collected. Bone mineral density (BMD), peripheral quantitative computed tomography (pQCT), micro-computed tomography (micro-CT), and mechanical tests were performed on the distracted callus. The rabbits were divided into three groups according to the timing of PTH (1-34) administration: 4 weeks during the distraction and consolidation phases (group D + C), 2 weeks of the distraction phase (group D), and the first 2 weeks of the consolidation phase (group C). A control group (group N) was administered saline for 4 weeks during the distraction and consolidation phases. Furthermore, to obtain histological findings, lower leg bones were collected from each rabbit at 2, 3, and 4 weeks after osteotomy, and tissue sections of the distracted callus were examined histologically. RESULTS: The BMD was highest in group C and was significantly higher than group D. In pQCT, the total cross-sectional area was significantly higher in groups D + C, D, and C than group N, and the cortical bone area was highest in group C and was significantly higher than group D. In micro-CT, group C had the highest bone mass and number of trabeculae. Regarding the mechanical test, group C had the highest callus failure strength, and this value was significantly higher compared to group N. There was no significant difference between groups D and N. The histological findings revealed that the distracted callus mainly consisted of endochondral ossification in the distraction phase. In the consolidation phase, the chondrocytes were almost absent, and intramembranous ossification was the main type of ossification. CONCLUSION: We found that the optimal timing of PTH (1-34) administration is during the consolidation phase, which is mainly characterized by intramembranous ossification.

Can fracture healing be accelerated by serum transfer in head trauma cases? An experimental head trauma model in rats.

OBJECTIVES: In this study, we aimed to investigate whether the positive union effect caused by head trauma could be transferred between individuals. MATERIALS AND METHODS: Seventy-two male rats with an average weight of 375 g were used in this study and divided into four groups including 18 in each group. Group 1 consisted of serum donor rats that were exposed to head trauma, while Group 2 consisted of study rats with long bone fractures that were given the serum obtained from the rats in Group 1, Group 3 included control rats with isolated long bone fractures, and Group 4 included control rats with both head trauma and long bone fractures. For radiological evaluation, the ratio of the width of the callus to the width of the neighboring diaphysis was considered as the callus-to-diaphyseal ratio in the study and control groups. Histopathological and radiological evaluations was made on Days 10, 20, and 30. RESULTS: In evaluation of the radiological data regarding the callus-to-diaphyseal ratio, Group 3 was found to have significantly lower radiological values than Group 4 on Day 10 (p=0.006). Group 2 had significantly higher values than Group 3 (p=0.02). On Day 20, Group 2 exhibited significantly higher radiological values than Group 3 (p=0.004), but lower than Group 4 (p=0.032). As for Day 30, Group 2 exhibited significantly higher radiological values than Group 3, but lower than Group 4 (p=0.001). In the evaluation of the Huo scores obtained for histopathological evaluation, there was no significant difference among the groups on Days 10, 20, and 30 (p=0.295, p=0.569, and p=0.729, respectively). CONCLUSION: Our study results suggest that the osteoinductive effect after head trauma can be transmitted between individuals by means of serum transfer.

Effects of different vardenafil doses on bone healing in a rat fracture model.

OBJECTIVES: We aimed to investigate the radiological, biomechanical, histopathological, histomorphometric, and immunohistochemical effects of different doses of vardenafil on fracture healing. MATERIALS AND METHODS: Fifty-one rats were divided into three groups. Group V5 was given 5 mg/kg/day of vardenafil; Group V10 was given 10 mg/kg/day of vardenafil; and the control group was given the same volume of saline. Six rats from each group were sacrificed on Day 14 (early period) and the remaining rats were sacrificed on Day 42 (late period). Callus/femoral volume and bone mineral density were measured using micro-computed tomography. Five femurs from each group in the late period were examined by biomechanical tests. In addition to the histopathological and histomorphometric evaluations, immunohistochemical analyses were performed to examine the levels of inducible nitric oxide synthase (iNOS), transforming growth factor-3 (TGF-ß3), and nuclear factor kappa B (NF-κB) proteins. RESULTS: Both doses of vardenafil increased primary bone volume and maximal bone fracture strength in late period, compared to the control group (p<0.05). Histological healing scores of vardenafil groups were significantly higher in early period (p<0.001). While cartilaginous callus/total callus ratio in early period was higher, callus diameter/femoral diameter ratio in late period was lower in vardenafil groups (p<0.01). The NF-κB immunopositivity in V10 group decreased in early period, compared to control group (p<0.001). The TGF-ß3 and iNOS immunopositivity increased in both V5 and V10 groups, compared to the control group in early period, but returned to normal in late period. CONCLUSION: During the first period of fracture healing process in which vasodilation is mostly required with increasing inflammation, vardenafil has ameliorating effects on the bone union and supports fracture healing.

Impaired soft and hard callus formation during fracture healing in diet-induced obese mice as revealed by 3D contrast-enhanced computed tomography imaging.

The impact of diabetes mellitus on bone fracture healing is clinically relevant as the patients experience delayed fracture healing. Even though efforts have been made to understand the detrimental effects of type 2 diabetes mellitus (T2DM) on the fracture healing process, the exact mechanisms causing the pathophysiological outcomes remain unclear. The aim of this study was to assess alterations in bone fracture healing (tibial fracture surgery, intramedullary pinning) of diet-induced obese (DIO) mice, and to investigate the in vitro properties of osteochondroprogenitors derived from the diabetic micro-environment. High-resolution contrast-enhanced microfocus X-ray computed tomography (CE-CT) enabled a simultaneous 3D assessment of the amount and spatial distribution of the regenerated soft and hard tissues during fracture healing and revealed that osteogenesis as well as chondrogenesis are altered in DIO mice. Compared to age-matched lean controls, DIO mice presented a decreased bone volume fraction and increased callus volume and adiposity at day 14 post-fracture. Of note, bone turnover was found altered in DIO mice relative to controls, evidenced by decreased blood serum osteocalcin and increased serum CTX levels. The in vitro data revealed that not only the osteogenic and adipogenic differentiation of periosteum-derived cells (PDCs) were altered by hyperglycemic (HG) conditions, but also the chondrogenic differentiation. Elevated PPARγ expression in HG conditions confirmed the observed increase in differentiated adipocytes in vitro. Finally, chondrogenesis-related genes COL2 and COL10 were downregulated for PDCs treated with HG medium, confirming that chondrogenic differentiation is compromised in vitro and suggesting that this may affect callus formation and maturation during the fracture healing process in vivo. Altogether, these results provide novel insights into the alterations of long bone fracture repair and suggest a link between HG-induced dysfunctionality of osteochondroprogenitor differentiation and fracture healing impairment under T2DM conditions.

Case Report: Hyperplastic Callus of the Femur Mimicking Osteosarcoma in Osteogenesis Imperfecta Type V.

Background: Osteogenesis imperfecta (OI) type V is a rare form of OI which is often characterized by hyperplastic callus. Misdiagnosis is a possibility due to its rarity and because patients involved are mostly in adolescence, a predisposing age for osteosarcoma. Here, we report this case and aim to improve understanding of patients with OI type V and avoid misdiagnosis. Case Presentation: A male, 14-year-old patient was admitted to Jiangxi Provincial People's Hospital affiliated to Nanchang University in August 2020 due to repeated fractures for more than 11 years and swelling in his right leg for more than 4 years. The patient was diagnosed with OI in 2014 due to repeated fracture and was treated with bisphosphonates. The swelling was accompanied by huge callus formation. Prior to admission to our hospital in 2016 osteosarcoma was suspected by imaging and pathology, and amputation was recommended. OI-V was confirmed after more than four years of follow-up and genetic diagnosis, and the affected limb was preserved. Conclusion: The history of OI and lack of rapid progression suggested OI-V with a hyperplastic callus. Combined with genetic testing, the diagnosis was OI-V. Although the patient was at a predisposing age for osteosarcoma, diagnosis and treatment should be based on the medical history of the patient, imaging,and genetic testing, and sometimes even time-consuming retrospective observation.

Changes in macrophage and inflammatory cytokine expressions during fracture healing in an ovariectomized mice model.

BACKGROUND: Macrophages and inflammatory cytokines play important roles in bone fracture healing. However, the expression patterns of macrophages and inflammatory cytokines during fracture healing under the condition of postmenopausal osteoporosis have not been fully revealed. METHODS: Tibia transverse fracture was established 12 weeks after ovariectomy or sham operation in 16-week old female mice. Tibias were harvested before fracture or 1, 3, 5, 7, 14, 21, 28 days after fracture for radiological and histological examinations. M1/M2 inflammatory macrophages, osteal macrophages and gene expressions of tumor necrosis factor-α, interleukin-6, interleukin-1ß and macrophage conversion related molecules in the fracture haematoma or callus were also detected. RESULTS: The processes of fracture healing, especially the phases of endochondral ossification and callus remodeling, were delayed in ovariectomized mice. The expressions of tumor necrosis factor-α and interleukin-6, but not interleukin-1ß, in the fracture haematoma or callus were disturbed. Expressions of tumor necrosis factor-α were decreased at 1, 14 and 21 days post-fracture (DPF), and were increased at 3, 5 and 7 DPF. Interleukin-6 expressions at 1, 3 and 21 DPF were significantly increased. We found the decreases in M1 and M2 macrophages at 1 DPF of the initial inflammatory stage. M2 macrophages at 14 DPF of the middle stage and osteal macrophages at 14, 21 and 28 DPF of the middle and late stages of fracture healing were also reduced in ovariectomized mice. CONCLUSIONS: The expressions of macrophages and inflammatory cytokines were impaired in ovariectomized mice, which might contribute partially to poor fracture healing.

A quantitative and non-invasive vibrational method to assess bone fracture healing: a clinical case study.

Orthopaedics needs a robust diagnostic tool that can help or even replace traditional radiography in bone healing assessment, thus reducing patient exposure to ionizing radiation. We used a vibrational method to assess the healing of a complex fracture treated with external fixation, exploiting a quantitative and non-invasive procedure. Callus stiffening was monitored from the time of surgery until the fixator was removed. Our approach overcomes previous limitations and involves a longer period of healing monitoring (about 9 months), very frequent tests (bi-weekly), and the analysis of a single test configuration. The healing process was monitored by analysing the percentage increments of the squared resonant frequencies (SFIs), related to the stiffness variation and the changes in the frequency response functions. The results were validated by X-rays images, and revealed that the most sensitive parameter to quantify the healing was the SFI of the first resonant frequency which increased by about 20% per month during the formation of the woven callus and up to about 50% at the end of healing completion. This study confirms the potential of the vibrational method as an alternative to radiography in fracture healing assessment.

Effect of lengthening speed on the quality of callus and complications in patients with congenital pseudarthrosis of tibia.

PURPOSE: This study aims to evaluate the effect of lengthening speed on the quality of callus and complications during distraction osteogenesis and describe an optimal lengthening speed in patients with congenital pseudarthrosis of tibia (CPT). METHODS: Twenty-seven patients with CPT with a minimum follow-up of 36 months who underwent limb lengthening surgery between 1997 and 2016 with external fixator only were included in this study. All patients underwent lengthening procedures after achieving complete bone union in this study. Regenerate quality is evaluated according to the Li classification on the X-ray taken one month after the end of the distraction period. Complications were noted in post-operative follow-up period. Receiver operator characteristics (ROC) curve analysis was performed to obtain optimal lengthening speed for these patients. RESULT: The mean age at the time of surgery was 5.74 years. The mean lengthening speed was 0.596 mm/day. Follow-up period of 136.14 months with a mean lengthening period of 92.4 days. Mean amount of lengthening was 5.44 cm for patients with CPT. Total rate of callus with good morphological quality was calculated as 66%. According to ROC analysis, optimal cut-off values of lengthening speed for the obtaining good morphological quality callus was 0.564 mm/day for tibial lengthening in CPT. There was a significantly positive correlation between complication rate and lengthening speed for each group. CONCLUSION: We recommend a mean lengthening rate of 0.56mm/day for the lengthening procedures with external fixator in patients with CPT who had complete bone union at the area of pseudarthrosis.

Analysis of low-dose estrogen on callus BMD as measured by pQCT in postmenopausal women.

BACKGROUND: Osteoporosis affects elderly patients of both sexes. It is characterized by an increased fracture risk due to defective remodeling of the bone microarchitecture. It affects in particular postmenopausal women due to their decreased levels of estrogen. Preclinical studies with animals demonstrated that loss of estrogen had a negative effect on bone healing and that increasing the estrogen level led to a better bone healing. We asked whether increasing the estrogen level in menopausal patients has a beneficial effect on bone mineral density (BMD) during callus formation after a bone fracture. METHODS: To investigate whether estrogen has a beneficial effect on callus BMD of postmenopausal patients, we performed a prospective double-blinded randomized study with 76 patients suffering from distal radius fractures. A total of 31 patients (71.13 years ±11.99) were treated with estrogen and 45 patients (75.62 years ±10.47) served as untreated controls. Calculated bone density as well as cortical bone density were determined by peripheral quantitative computed tomography (pQCT) prior to and 6 weeks after the surgery. Comparative measurements were performed at the fractured site and at the corresponding position of the non-fractured arm. RESULTS: We found that unlike with preclinical models, bone fracture healing of human patients was not improved in response to estrogen treatment. Furthermore, we observed no dependence between age-dependent bone tissue loss and constant callus formation in the patients. CONCLUSIONS: Transdermally applied estrogen to postmenopausal women, which results in estrogen levels similar to the systemic level of premenopausal women, has no significant beneficial effect on callus BMD as measured by pQCT, as recently shown in preclinical animal models. TRIAL REGISTRATION: Low dose estrogen has no significant effect on bone fracture healing measured by pQCT in postmenopausal women, DRKS00019858 . Registered 25th November 2019 - Retrospectively registered. Trial registration number DRKS00019858 .

Effect of kirenol on the interaction between the WNT/ß-Catenin and RUNX2/TCF/LEF1 pathways in fracture healing in vivo.

OBJECTIVE: This study aimed to determine the effects of a natural diterpenoid, kirenol, on fracture healing in vivo in an experimental rat model of femur fracture and investigate its potential mechanism of action via the Wnt/ß-catenin pathway. METHODS: In this study, 64 male Wistar albino rats aged 5-7 weeks and weighing 261-348 g were randomly divided into 8 groups from A to L, with eight rats in each group. Standardized fractures were created in the right femurs of the rats and then fixed with an intramedullary Kirschner wire. Four experimental groups were administered 2 mg/kg/day kirenol (Groups C and G) and 4 mg/kg/day (Groups D and H) kirenol by oral gavage.Thereafter, the animals were sacrificed at two time points as follows: on the 10th day (Groups B, C and D) and on the 21st day (Groups F, G and H) after the surgery; fracture healing in each group was assessed radiologically and histopathologically. The Radiographic Union scale of tibia fracture scoring system was used in the radiological examination; callus volume and density were measured using computed tomography. In the histopathologic examination, the scoring system described by Huo et al. was used. Additionally, the mechanism of action was evaluated based on the analyses of protein expression of Wnt3a, LRP5, TCF-LEF1, ß-catenin, and Runx-2 proteins using western blot analysis. RESULTS: Among the animals sacrificed on the 10th day after the surgery, the highest histopathological and radiological scores were observed in Group D (p<0.05). Furthermore, the callus density (p<0.05) was highest in Group D. Among the animals sacrificed on the 21st day, the highest histopathological and radiological scores were found in Group H, although the differences among the groups were not significant (p>0.05). The callus volume and density were the highest in Groups G and H, respectively, although the differences among groups were not significant. CONCLUSION: Kirenol may improve fracture healing in a dose-dependent manner with the early activation of the Wnt/ß-catenin pathway and the activation of the Runx-2 pathway.

Oral administration of bovine lactoferrin accelerates the healing of fracture in ovariectomized rats.

INTRODUCTION: Lactoferrin has recently been reported for its potent bone growth effects. However, the effects of lactoferrin on the healing process of fragility fracture have not yet been studied, so the purpose of this study is to investigate whether oral administration of lactoferrin can promote the fracture healing in an OVX animal model. MATERIALS AND METHODS: Three months after bilateral ovariectomy, all rats underwent unilateral tibial osteotomy and were then randomly divided into control group and bovine lactoferrin (bLF) group. At 4 and 8 weeks post-fracture, animals were sacrificed, and the fractured tibiae and serum samples were collected for evaluation. RESULTS: Our results showed that bLF treatment not only accelerated the bone growth at an early stage of OPF healing but also shortened the remolding process of OPF healing. When compared to control group, bLF treatment induced a significant rise in callus BMD (by 35.0% at 4 weeks and by 39.7% at 8 weeks; both p < 0.05) consistent with enhanced biomechanical strength of the callus, with ultimate force increased by 3.39-fold at 4 weeks (p < 0.05) and 1.95-fold at 8 weeks (p < 0.05). Besides, bLF administration resulted in a substantial increase in serum levels of BALP and a significant decrease in serum levels of TRAP 5b and TNF-α. Moreover, both the RANKL/OPG mRNA ratio and the expression of TNF-α in the callus of bLF-treated group were markedly lower than those in the control group. CONCLUSIONS: At a dose of 85mg/kg/day orally administrated bLF potently promoted the bone healing following tibial fracture in OVX rats.

From two stages to one: acceleration of the induced membrane (Masquelet) technique using human acellular dermis for the treatment of non-infectious large bone defects.

INTRODUCTION: The induced membrane technique for the treatment of large bone defects is a two-step procedure. In the first operation, a foreign body membrane is induced around a spacer, then, in the second step, several weeks or months later, the spacer is removed and the Membrane pocket is filled with autologous bone material. Induction of a functional biological membrane might be avoided by initially using a biological membrane. In this study, the effect of a human acellular dermis (hADM, Epiflex, DIZG gGmbH) was evaluated for the treatment of a large (5 mm), plate-stabilised femoral bone defect. MATERIAL AND METHODS: In an established rat model, hADM was compared to the two-stage induced membrane technique and a bone defect without membrane cover. Syngeneous spongiosa from donor animals was used for defect filling in all groups. The group size in each case was n = 5, the induction time of the membrane was 3-4 weeks and the healing time after filling of the defect was 8 weeks. RESULTS: The ultimate loads were increased to levels comparable with native bone in both membrane groups (hADM: 63.2% ± 29.6% of the reference bone, p < 0.05 vs. no membrane, induced membrane: 52.1% ± 25.8% of the reference bone, p < 0.05 vs. no membrane) and were significantly higher than the control group without membrane (21.5%). The membrane groups were radiologically and histologically almost completely bridged by new bone formation, in contrast to the control Group where no closed osseous bridging could be observed. CONCLUSION: The use of the human acellular dermis leads to equivalent healing results in comparison to the two-stage induced membrane technique. This could lead to a shortened therapy duration of large bone defects.

Do antiosteoporotic drugs improve bone regeneration in vivo?

PURPOSE: Treatment of complex fractures in the elderly is a challenge for operative reconstruction due to degraded bone structure. Early peri-operative bone anabolic treatment could improve new bone formation, avoid implant loosening and accelerate fracture healing. METHODS: To compare the osteoanabolic potential of different drugs after distraction osteogenesis, 168 female Sprague-Dawley rats underwent lengthening of the right femur using a monolateral external fixator. Animals were randomly divided into six groups: vehicle-injected group, PTH(1-34), raloxifen, strontium ranelate, alendronate and simvastatin. Histomorphometry, CT-scanning, DEXA- and biomechanical analysis were performed to evaluate new bone formation, callus volume, mineralisation and biomechanical strength. Expression of bone metabolic mediators and differentiation indicators of distracted and intact bone were examined by RT-PCR and western blot. RESULTS: Histological analysis showed significant increase of the bone mass after treatment with PTH(1-34), raloxifen and strontium ranelate (p = 0.02). Raloxifen increased bone mineral content (BMC) of the whole distracted femur significantly (p = 0.007). Callus volume was significantly larger in the PTH(1-34), raloxifen and simvastatin groups (p = 0.001) compared to control. Ultimate load of distracted new formed bone was increased in PTH(1-34) and raloxifen groups. It seems that PTH(1-34) and raloxifen have a stronger effect on bone where a repair response is activated. Strontium ranelate demonstrates similar effects to PTH regarding new bone formation but shows low values for mineralisation and biomechanical strength. CONCLUSION: This study suggests that peri-operative treatment of complex and/or osteoporotic fractures with PTH(1-34) and raloxifen might be useful as a stimulator of bone formation and mineralisation to shorten the consolidation time in humans.

Carbon/PEEK nails: a case-control study of 22 cases.

BACKGROUND: Interest around carbon/PEEK plates and nails has been raising. The elastic modulus close to the bone, the high load-carrying capacity and radiolucency make CFR/PEEK materials a potential breakthrough. In the literature, there are abundant data about CFR/PEEK plates in the treatment of proximal humerus, distal radius and distal fibula fractures. In patients affected by bone metastasis, CFR/PEEK nails were proved effective and safe with 12 months of follow-up. Very little is known about performances of CFR/PEEK nails in patients affected by other pathologies. PURPOSES: The aim of the study was to evaluate safety and efficacy of CFR/PEEK nails in the treatment of various pathological conditions. It was also investigated whatever radiolucency of this nails could lead to a more objective evaluation of bone callus or disease site. PATIENTS AND METHODS: In the study group were included 20 patients (22 bone segments) who underwent CFR/PEEK nail implantation (eight humerus, one tibia, nine femur and four knee arthrodesis). They were affected by pathological fractures, and in four cases, they required an arthrodesis of the knee. They were retrospectively evaluated considering nail failures and bone callus or disease progression (RUSH scores). Mean follow-up time was 11 months (min 6.8-max 20.3). In the control group were included patients treated with titanium nails in the same institution for the same pathologies. An interclass correlation coefficient (ICC) analysis was performed in both groups considering RUSH scores by two expert surgeon from two institution to assess whether radiolucency could lead to a more objective evaluation of disease or bone callus site. RESULTS: The ICC of mean values between RUSH scores was 0.882 (IC 95%: 0.702-0.953) in the CFR/PEEK group, while it was 0.778 (IC 95%: 0.41-0.91) in the titanium group. Observers' evaluation showed a significantly higher obscuration by titanium nails than by CFR/PEEK nails. No osteosynthesis failures were reported in both groups. CONCLUSIONS: Our results confirm the safety of CFR/PEEK nails in the short-medium term. The radiolucency of these materials led our observers to perform more objective evaluations of bone callus formation or disease progression compared to the titanium group given the higher ICC. LEVEL OF EVIDENCE: III Case-control therapeutic study.