Aims. To evaluate whether low-intensity pulsed ultrasound (LIPUS) accelerates bone healing at osteotomy sites and promotes functional recovery after open-wedge high tibial osteotomy (OWHTO). Methods. Overall, 90 patients who underwent OWHTO without bone grafting were enrolled in this nonrandomized retrospective study, and 45 patients treated with LIPUS were compared with 45 patients without LIPUS treatment in terms of bone healing and functional recovery postoperatively. Clinical evaluations, including the pain visual analogue scale (VAS) and Japanese Orthopaedic Association (JOA) score, were performed preoperatively as well as six weeks and three, six, and 12 months postoperatively. The progression rate of gap filling was evaluated using anteroposterior radiographs at six weeks and three, six, and 12 months postoperatively. Results. The pain VAS and JOA scores significantly improved after OWHTO in both groups. Although the LIPUS group had better pain scores at six weeks and three months postoperatively, there were no significant differences in JOA score between the groups. The lateral hinge united at six weeks postoperatively in 34 (75.6%) knees in the control group and in 33 (73.3%) knees in the LIPUS group. The progression rates of gap filling in the LIPUS group were 8.0%, 15.0%, 27.2%, and 46.0% at six weeks and three, six, and 12 months postoperatively, respectively, whereas in the control group at the same time points they were 7.7%, 15.2%, 26.3%, and 44.0%, respectively. There were no significant differences in the progression rate of gap filling between the groups. Conclusion. The present study demonstrated that LIPUS did not promote bone healing and functional recovery after OWHTO with a locking plate. The routine use of LIPUS after OWHTO was not recommended from the results of our study. Cite this article: Bone Jt Open 2022;3(11):885–893

Aims. Although low-intensity pulsed ultrasound (LIPUS) combined with disinfectants has been shown to effectively eliminate portions of biofilm in vitro, its efficacy in vivo remains uncertain. Our objective was to assess the antibiofilm potential and safety of LIPUS combined with 0.35% povidone-iodine (PI) in a rat debridement, antibiotics, and implant retention (DAIR) model of periprosthetic joint infection (PJI). Methods. A total of 56 male Sprague-Dawley rats were established in acute PJI models by intra-articular injection of bacteria. The rats were divided into four groups: a Control group, a 0.35% PI group, a LIPUS and saline group, and a LIPUS and 0.35% PI group. All rats underwent DAIR, except for Control, which underwent a sham procedure. General status, serum biochemical markers, weightbearing analysis, radiographs, micro-CT analysis, scanning electron microscopy of the prostheses, microbiological analysis, macroscope, and histopathology evaluation were performed 14 days after DAIR. Results. The group with LIPUS and 0.35% PI exhibited decreased levels of serum biochemical markers, improved weightbearing scores, reduced reactive bone changes, absence of viable bacteria, and decreased inflammation compared to the Control group. Despite the greater antibiofilm activity observed in the PI group compared to the LIPUS and saline group, none of the monotherapies were successful in preventing reactive bone changes or eliminating the infection. Conclusion. In the rat model of PJI treated with DAIR, LIPUS combined with 0.35% PI demonstrated stronger antibiofilm potential than monotherapy, without impairing any local soft-tissue. Cite this article: Bone Joint Res 2024;13(7):332–341

Aims. This 501-patient, multi-centre, randomised controlled trial sought to establish the effect of low-intensity, pulsed, ultrasound (LIPUS) on tibial shaft fractures managed with intramedullary nailing. We conducted an economic evaluation as part of this trial. Patients and Methods. Data for patients’ use of post-operative healthcare resources and time taken to return to work were collected and costed using publicly available sources. Health-related quality of life, assessed using the Health Utilities Index Mark-3 (HUI-3), was used to derive quality-adjusted life years (QALYs). Costs and QALYs were compared between LIPUS and control (a placebo device) from a payer and societal perspective using non-parametric bootstrapping. All costs are reported in 2015 Canadian dollars unless otherwise stated. Results. With a cost per device of $3,995, the mean cost was significantly higher for patients treated with LIPUS versus placebo from a payer (mean increase = $3647, 95% confidence interval (CI) $3244 to $4070; p < 0.001) or a societal perspective (mean increase = $3425, 95% CI $1568 to $5283; p < 0.001). LIPUS did not provide a significant benefit in terms of QALYs gained (mean difference = 0.023 QALYs, 95% CI -0.035 to 0.069; p = 0.474). Incremental cost-effectiveness ratios of LIPUS compared with placebo were $155 433/QALY from a payer perspective and $146 006/QALY from a societal perspective. Conclusion. At the current price, LIPUS is not cost-effective for fresh tibial fractures managed with intramedullary nailing. Cite this article: Bone Joint J 2017;99-B:1526–32

We evaluated the effect of low-intensity pulsed ultrasound stimulation (LIPUS) on the remodelling of callus in a rabbit gap-healing model by bone morphometric analyses using three-dimensional quantitative micro-CT. A tibial osteotomy with a 2 mm gap was immobilised by rigid external fixation and LIPUS was applied using active translucent devices. A control group had sham inactive transducers applied. A region of interest of micro-CT was set at the centre of the osteotomy gap with a width of 1 mm. The morphometric parameters used for evaluation were the volume of mineralised callus (BV) and the volumetric bone mineral density of mineralised tissue (mBMD). The whole region of interest was measured and subdivided into three zones as follows: the periosteal callus zone (external), the medullary callus zone (endosteal) and the cortical gap zone (intercortical). The BV and mBMD were measured for each zone. In the endosteal area, there was a significant increase in the density of newly formed callus which was subsequently diminished by bone resorption that overwhelmed bone formation in this area as the intramedullary canal was restored. In the intercortical area, LIPUS was considered to enhance bone formation throughout the period of observation. These findings indicate that LIPUS could shorten the time required for remodelling and enhance the mineralisation of callus

The haematoma occurring at the site of a fracture is known to play an important role in bone healing. We have recently shown the presence of progenitor cells in human fracture haematoma and demonstrated that they have the capacity for multilineage mesenchymal differentiation. There have been many studies which have shown that low-intensity pulsed ultrasound (LIPUS) stimulates the differentiation of a variety of cells, but none has investigated the effects of LIPUS on cells derived from human fracture tissue including human fracture haematoma-derived progenitor cells (HCs). In this in vitro study, we investigated the effects of LIPUS on the osteogenic activity of HCs. Alkaline phosphatase activity, osteocalcin secretion, the expression of osteoblast-related genes and the mineralisation of HCs were shown to be significantly higher when LIPUS had been applied but without a change in the proliferation of the HCs. These findings provide evidence in favour of the use of LIPUS in the treatment of fractures

We investigated the effects of low-intensity pulsed ultrasound on distraction osteogenesis in a rabbit model. Callotasis of the right tibia was performed in 70 male Japanese white rabbits using mini-external fixators. In the first part of the study in 64 animals using normal distraction (waiting period seven days; distraction rate 0.5 mm/12 hours; distraction period ten days), we evaluated the distraction site by radiography, measurement of the bone mineral density (BMD), mechanical testing, and histology. In the second part in six rabbits using fast distraction (waiting period 0 days; distraction rate 1.5 mm/12 hours; distraction period seven days) the site was evaluated radiologically. Half of the animals (35) had received ultrasound to their right leg (30mW/cm. 2. ) for 20 minutes daily after ceasing distraction (ultrasound group), while rigid fixation only was maintained in the other half (control group). With normal distraction, the hard callus area, as shown by radiography, the BMD, and the findings on mechanical testing, were significantly greater in those receiving ultrasound than in the control group. Histological analysis showed no tissue damage attributable to exposure to ultrasound. With fast distraction, immature bone regeneration was observed radiologically in the control group, while bone maturation was achieved in the ultrasound group. We conclude that ultrasound can accelerate bone maturation in distraction osteogenesis in rabbits, even in states of poor callotasis

Aims

The aim of this double-blind prospective randomised controlled trial was to assess whether low intensity pulsed ultrasound (LIPUS) accelerated or enhanced the rate of bone healing in adult patients undergoing distraction osteogenesis.

This study was designed to test the hypothesis that the sensory innervation of bone might play an important role in sensing and responding to low-intensity pulsed ultrasound and explain its effect in promoting fracture healing. In 112 rats a standardised mid-shaft tibial fracture was created, supported with an intramedullary needle and divided into four groups of 28. These either had a sciatic neurectomy or a patellar tendon resection as control, and received the ultrasound or not as a sham treatment. Fracture union, callus mineralisation and remodelling were assessed using plain radiography, peripheral quantitative computed tomography and histomorphology. Daily ultrasound treatment significantly increased the rate of union and the volumetric bone mineral density in the fracture callus in the neurally intact rats (p = 0.025), but this stimulating effect was absent in the rats with sciatic neurectomy. Histomorphology demonstrated faster maturation of the callus in the group treated with ultrasound when compared with the control group. The results supported the hypothesis that intact innervation plays an important role in allowing low-intensity pulsed ultrasound to promote fracture healing

The December 2024 Wrist & Hand Roundup. 360. looks at: Variability in thumb ulnar collateral ligament rupture management across the UK: survey insights; Identifying five distinct hand osteoarthritis pain phenotypes highlights the impact of biopsychosocial factors; Long-term outcomes of MAÏA TMC joint prosthesis for osteoarthritis: a possible alternative to trapeziectomy; Diagnostic and management strategies for malignant melanoma of the hand; Early versus delayed surgery for distal radius fractures: comparable outcomes but higher complications in delayed treatment; Perioperative anticoagulant and antiplatelet use does not increase complications in wide-awake hand surgery; Variability in treatment of metacarpal shaft fractures highlights need for standardized care; Low-intensity pulsed ultrasound ineffective in reducing time to union for scaphoid nonunion post-surgery

Introduction and Objective. Nonunion is incomplete healing of fracture and fracture that lacks potential to heal without further intervention. Nonunion commonly presents with persistent pain, swelling, or instability. Those symptoms affect patient quality of life. It is known that using low intensity pulsed ultrasound (LIPUS) for fresh fractures promotes healing. However, effectiveness of LIPUS for nonunion is still controversial. If LIPUS is prove to be effective for healing nonunion, it can potentially provide an alternative to surgery. In addition, we can reduce costs by treating nonunion with LIPUS than performing revision surgery. Materials and Methods. The two authors carried out a systematic search of PubMed, Ovid MEDLINE, and the Cochrane Library. Meta-analysis of healing rate in nonunion and delayed union patients who underwent LIPUS was conducted based on the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) instruction method using a random effects model. Results. The initial search identified 652 articles. Of these, 541 were excluded on the basis of the title because they were either a review paper or covered an unrelated topic. The abstracts of the remaining 111 articles were examined further. That review resulted in a sample of 12 articles. We performed a meta-analysis with a random effects model using Open Meta Analyst software. The result of pooled effect size of healing rate was 73.4% (95%CI: 65.3–81.6%). Due to the fact that nonunion lacks potential to heal without further intervention, we suggest that the therapeutic effect of 73.4% from LIPUS is sufficiently effective. As far as we know, there are no trials comparing the therapeutic effectiveness of surgery and LIPUS, so it cannot be said which is more advantageous. However, the healing rate of revision surgery was reported between 68–96%; therefore, our result is within that range. Thus, if surgery is difficult due to complications, we can recommend LIPUS. Conclusions. Meta-analysis of healing rate of nonunion treated by low-intensity pulsed ultrasound is 73.4%, which suggests sufficient therapeutic effectiveness. Furthermore, we can say that LIPUS may provide an alternative treatment for nonunion patients who cannot tolerate revision surgery due to complications

Introduction. Articular cartilage injuries have a limited potential to heal and, over time, may lead to osteoarthritis, an inflammatory and degenerative joint disease associated with activity-related pain, swelling, and impaired mobility. Regeneration and restoration of the joint tissue functionality remain unmet challenges. Stem cell-based tissue engineering is a promising paradigm to treat cartilage degeneration. In this context, hydrogels have emerged as promising biomaterials, due to their biocompatibility, ability to mimic the tissue extracellular matrix and excellent permeability. Different stimulation strategies have been investigated to guarantee proper conditions for mesenchymal stem cell differentiation into chondrocytes, including growth factors, cell-cell interactions, and biomaterials. An interesting tool to facilitate chondrogenesis is external ultrasound stimulation. In particular, low-intensity pulsed ultrasound (LIPUS) has been demonstrated to have a role in regulating the differentiation of adipose mesenchymal stromal cells (ASCs). However, chondrogenic differentiation of ASCs has been never associated to a precisely measured ultrasound dose. In this study, we aimed to investigate whether dose-controlled LIPUS is able to influence chondrogenic differentiation of ASCs embedded in a 3D hydrogel. Materials and Methods. Human adipose mesenchymal stromal cells at 2∗10. 6. cells/mL were embedded in a hydrogel ratio 1:2 (VitroGel RGD®) and exposed to LIPUS stimulation (frequency: 1 MHz, intensity: 250 mW/cm. 2. , duty cycle: 20%, pulse repetition frequency: 1 kHz, stimulation time: 5 min) in order to assess its influence on cell differentiation. Hydrogel-loaded ASCs were cultured and differentiated for 2, 7, 10 and 28 days. At each time point cell viability (Live&Dead), metabolic activity (Alamar Blue), cytotoxicity (LDH), gene expression (COL2, aggrecan, SOX9, and COL1), histology and immunohistochemistry (COL2, aggrecan, SOX9, and COL1) were evaluated respect to a non-stimulated control. Results. Histological analysis evidenced a uniform distribution of ASCs both at the periphery and at the center of the hydrogel. Live & Dead test evidenced that the encapsulated ASCs were viable, with no signs of cytotoxicity. We found that LIPUS induced chondrogenesis of ASCs embedded in the hydrogel, as demonstrated by increased expression of COL2, aggrecan and SOX9 genes and proteins, and decreased expression of COL1 respect to the non-stimulated control. Conclusions. These results suggest that the LIPUS treatment could be a valuable tool in cartilage tissue engineering, to push the differentiation of ASCs encapsulated in a 3D hydrogel

Background. Fractures of the metatarsal bones are the most frequent fracture of the foot. Up to 70% involve the fifth metatarsal bone, of which approximately eighty percent are located proximally. Low-intensity pulsed ultrasound (LIPUS) has been shown to be a useful adjunct in the treatment of delayed fractures and non unions. However, there is no study looking at the success rate of LIPUS in fifth metatarsal fracture delayed unions. Objectives. The aim of our study was to investigate the use of LIPUS treatment for delayed union of fifth metatarsal fractures. Study Design & Methods. A retrospective review of patients who were treated with LIPUS following a delayed union of fifth metatarsal fracture was conducted over a three-year period (2013 – 2015). Delayed union was defined as lack of clinical and radiological evidence of union, bony continuity or bone reaction at the fracture site if 3 months has elapsed from the initial injury. Results. There were thirty patients (9 males, 21 females) in our cohort. The average age was 39.3 years. Type 2 fractures made up 43% of our cohort. Twenty-seven (90%) patients went on to progress to union clinically and radiologically following LIPUS treatment. Smoking (p=0.014) and size of fracture gap (p=0.045) were predictive of non-union. Conclusions. This is the first study looking at the use of LIPUS in the treatment of delayed union of fifth metatarsal fractures. We report a success rate of 90%. There is a role in the use of LIPUS in delayed union of fifth metatarsal fractures and can serve as an adjunct prior to consideration of surgery

Introduction. Low-intensity pulsed ultrasound (LIPUS) has been reported to enhance healing of fracture and nonunion. Bone morphogenetic protein-7 (BMP-7) has also been reported to promote bone formation. Recently, we demonstrated progenitor cells with osteogenic/chondrogenic differentiation potential existed in human fracture hematoma and nonunion tissue. Hypothesis. We hypothesised the combined application of LIPUS and BMP-7 would cause major effect on osteogenesis of hematoma-derived cells (HCs) and nonunion tissue-derived cells (NCs). Materials & Methods. HCs and NCs were isolated, and cultured. The cells were divided into two groups: (1) BMP-7 group: cells cultured in osteogenic medium (OM), and (2) BMP-7 + LIPUS group: cells cultured in OM with LIPUS treatment. LIPUS (30 mW/cm2, intensity at 1.5 MHz) was given for 20 minutes daily. Osteogenic differentiation potential and proliferation were analysed. Results. ALP activity, the gene expression of osteogenic genes, and mineralisation of HCs and NCs were shown to be higher in BMP-7 + LIPUS group than in BMP-7 group. There was no significant difference in cell proliferation between the two groups. Discussion. Our findings demonstrated the significant effect of LIPUS on the osteogenic differentiation of HCs and NCs induced by BMP-7. This study may provide significant evidence for the clinical combined application of BMP-7 and LIPUS for the treatment of severe bone fracture and nonunion

Objective. To determine what factors affect fracture healing with low-intensity pulsed ultrasound (LIPUS) for delayed unions and nonunions. Patients. A consecutive cohort of 101 delayed unions and 50 nonunions after long bone fractures treated with LIPUS between May 1998 and April 2007. Main Outcome and Measurements. Radiographic determination of osseous bone union within one year after start of LIPUS therapy. Recognition of predictable factors that affect treatment results of LIPUS. Main Results. 1) Delayed union group (n=101): Seventy-five delayed union (74.3%) united without an additional major surgical intervention. Failure of LIPUS therapy was associated with types of nonunion (atrophic vs. hypertrophic, RR 23.72 [95%CI: 1.20–11.5], p<0.01), instability at fracture site (unstable vs. stable, RR 3.03 [1.67–5.49], p<0.001), and maximum fracture gap size not less than 9 mm (RR 3.30 [1.68–6.45]). 2) 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 (IM nail vs. others, RR 4.50 [95%CI: 1.69–12.00], p<0.001), instability at fracture site (unstable vs. stable, RR 4.56 [2.20–9.43], p<0.0001), and maximum fracture gap size not less than 8 mm (RR 5.09 [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

Background: Low-intensity pulsed ultrasound (LIPUS) was shown to accelerate fracture healing with delayed unions and non-unions as well as fresh fractures. Objective: To know the factors which affected clinical results of LIPUS treatment for delayed unions and non-unions. Design: Prospective Cohort Study. Setting: University Hospital. Intervention: 192 delayed or non-unions of long bone or clavicle were treated by LIPUS from May 1998 to April 2007. Background factors (age and gender of patient, history of smoking, personality of each fracture, intervals from injury to application of LIPUS treatment) were prospectively investigated. All patients were followed up at the outpatient clinic and AP and lateral view of radiographs were taken usually every 4 weeks. Main outcome of this study was set as “bone union” and it was defined as cortical continuity in a minimum of three cortices on two views on radiographs and without pain at the fracture site on palpation. Main Outcome Measurement: The overall success rate was 75%, and the success rate of subcutaneous bones were higher (tibia: 81%, radius and ulna: 80%)than that of deeper bone (femur: 64%, humerus 58%). Logistic multi-variant regression showed that the greatest gap size between the main bone fragments (p< 0.0001), instability of a fracture site (p< 0.0001), and the intervals between injury to the application of LIPUS (p< 0.05) were independent predictors for the success of LIPUS treatment for delayed and non-unions. Conclusion: We believe that the greatest gap size of main fragments, instability of a fracture site, and the age of non-union are the factors that affected LIPUS clinical results

Aims: Low-intensity pulsed ultrasound has shown acceleration of bone healing in fresh fractures. The goal of this study is to assess the effect of low-intensity ultrasound on bone healing in established nonunion cases and following osteotomy. Methods: A non randomized trial on 29 cases, located in the tibia, femur, radius/ulna, scaphoid, humerus, metatarsal and clavicle, met the criteria for established nonunions. On average, the post-fracture period prior to the start of ultrasound treatment was 61 weeks. Daily, twenty-minute applications of low-intensity ultrasound at the site of the non-union were performed by the patients at home. In a placebo-controlled, randomized clinical trial double-blinded trial, 97 adults, who had undergone an osteotomy of the lower extremity were randomly allocated an active- or placebo ultrasound device. Every two weeks the patients were examined both clinical and radiological. Results: Twenty-five of the twenty-nine non-union cases (86%) healed in an average treatment time of 22 weeks. Forty-six patients (75 bones) were treated with an active ultrasound device and 44 patients (78 bones) with a placebo device were eligible for analysis. An overall reduction of time to consolidation of 32% was established. A nonunion, which had to be treated operatively, occurred in four cases in the placebo group and in none in the active group. No other prognostic variables were found. Conclusions: Low-intensity ultrasound can stimulate bone healing in osteotomies and nonunions. In patients with a fracture or osteotomy, who are at high risk of developing nonunion, low-intensity ultrasound can be valuable as additional therapy

Introduction: Goal of study to demonstrate that treatment with low-intensity pulsed ultrasound [LIPUS] results in greater increases in bone density and greater reductions in bone gap area as compared to sham control in tibia fractures with delayed union (no progression of healing for at least four months). Methods: Two primary effectiveness variables, change of bone density and gap area during treatment, were selected as surrogates for bone healing. Abbreviated treatment period was maximum that sham treatment could be administered ethically. Both variables measured by blinded central reviewers from CT-scans taken before/after termination of treatment. All adverse events recorded, evaluated. Treatment duration was 16wks. Patients instructed to apply device once daily for 20 minutes. Control devices were visually identical but did not transmit ultrasound waves. Neither patients nor physicians could recognize shams. Results: 101 patients enrolled (51 LIPUS, 50 sham), mean age 42.6 (active) versus 45.1 years (sham). Based on log-transformed data, mean improvement in bone density was 1.34 (90% CI 1.14 to 1.57) times greater for patients randomized to LIPUS compared to sham (p=0.002). A mean reduction in bone gap area also favored LIPUS treatment (p=0.014). Conclusion: Double-blind, intent-to-treat analyses demonstrated statistically significant superior effectiveness for LIPUS device compared to sham in terms of both endpoints over 16wks of treatment. Estimated increase in bone density among patients randomized to LIPUS treatment was 34% greater than among patients randomized to sham. A significantly greater mean reduction in bone gap area after LIPUS treatment was also shown. Evaluation of adverse events showed that ultrasound therapy is safe

Ultrasound has been shown to have positive biological effects, including increased angiogenic, chondrogenic, and osteogenic activities. The aim of our study was to evaluate the evidence available in the scientific literature for the ultrasound treatment for tendon healing. To identify “best evidence” published research a computerized literature search of Medline, Cochrane, PEDro, IME, IBECS and ENFISPO. Keywords used to identify the study population and interventions were: ultrasound, low intensity pulsed ultrasound, physiotherapy, clinical trial, meta-analysis, practice guideline, randomized controlled trial, repair tendon and tendon healing. The scientific evidence of the group of selected documents were measured using the scale described by the US Preventive Task Force. The assignment of the evidence level to each study was evaluated independently by two reviewers without communication among them. To determine inter-rather reliability Kappa index it was used (K) with a value of CI of 95%. The study populations were 39 pertinent recovered documents. The findings suggest that therapeutic ultrasound can increase in collagen synthesis and enhance the maturation of collagen fibrils of repairing tendons. Researchers have reported that therapeutic ultrasound could facilitate tissue recovery and US with dosages between 0.125–3 W/cm2 have been used in the treatment of tendon ruptures reported an improvement in both strength and energy absorption capacity of repairing rabbit or rat tendons with 1-MHz continuous US. Best results were: continuous US at 1 MHz, 0.5w/cm2 starting from day 5 after injury, 20 treatment sessions, 4 mi each session. There is not a general consensus on the choice of parameters for US treatment and the evidence for efficacy of therapeutic. Limits of studies: The time needed to develop such an interface in humans was reported to be much longer than that reported in animal models. Continuous and low-intensity pulsed ultrasound was able to accelerate tendon healing and facilitating earlier physiotherapy

Over the past 100 years, experimental and clinical studies have tried to accelerate fracture healing and to bring ununited fractures to union . Besides advances in surgical management, non-surgical means have been investigated. Mechanical enhancement of fracture healing using controlled micromotion has been used with some success but does not seem to have been applied to nonunions. Electrical stimulation has been found effective in hypertrophic nonunions, but less so in atrophic nonunions and in the presence of a gap; the various devices available have never gained wide acceptance for various reasons. Low-intensity pulsed ultrasound has been found effective to heal non-unions, especially hypertrophic, with a success rate around 85 % . High-energy extracorporeal shock wave therapy (ESWT) has also been found effective in non-union management, but this is still controversial and there is a need for prospective controlled studies. Biological action has also been attempted for a long time. All attempts to stimulate fracture healing using systemic drugs, diet supplementations, vitamins or hormones have been essentially unsuccessful unless when correcting a pre-existing deficiency . More recently, several molecules have demonstrated an osteoinductive capacity in animal studies; human recombinant BMP-2 is currently under investigation in clinical trials. Percutaneous injection of bone marrow into a non-union has also proved of interest, particularly following centrifugation to increase the number of osteoprogenitor cells; current research aims at selecting these cells prior to injection. To conclude, a number of non-surgical means are currently available which may be of interest to accelerate fracture healing or to heal nonunions. Some are totally non-invasive, others are minimally invasive; early results have been encouraging for several of them, but there is still a need for clinical validation using prospective controlled studies. Some of those methods may well turn into alternate solutions to surgery in the future . Cost is currently a limiting factor, as long as it is not reimbursed by national health systems in most countries

INTRODUCTION. Several reports suggest that low-intensity pulsed ultrasound stimulation (LIPUS) facilitates chondrogenesis. 1). Recently it has been suggested that LIPUS may be transmitted via Integrin: a protein which mediates cellular attachment between cells and extracellular matrix. 2). In this study, the Arg-Gly-Asp (RGD) amino acid sequence, which is a ligand of Integrin, was induced to the fibroin substrates by either gene transfer or physical mixing, and the variation of chndrocyte response to LIPUS was evaluated. EXPERIMENTAL METHODS. Three kinds of culture dishes coated with three diffrent fibroin aqueous solutions were prepared: 1 wild-type, 2 transgenic and 3 mixed. The wild-type aqueous solution was prepared from Bombyx mori silkworm cocoons. The transgenic aqueous solution was prepared from Bombyx mori silkworm cocoons in which RGD was interfused in the fibroin light chain. 3). The mixed aqueous solution was prepared simply by blending RGD peptides with the wild-type fibroin aqueous solution. Chondrocytes were asepically harvested from the joints of 4-week-old Japanese white rabbits and then subcultured on T-flasks and seeded at 2.0 × 10. 5. cells/dish. LIPUS stimulation, with spatial and temporal average intensity of 30 mW/cm. 2. and a frequency of 1.71 MHz with a 200 ms tone burst repeated at 1.0 kHz, was applied to the chondrocytes at 12, 36, 60 hours and administered for 20 minutes each time. GAG production and the number of chondrocytes were measured by the Dimethylmethylene blue (DMMB) method. 4). and the LDH method. 5). , respectively. Extracted mRNA from the chondrocytes was analyzed by using the Syber Green method, where the primers were designed for glyceraldehyde-3-phosphate dehydrogenase (GAPDH) as the house-keeping gene, aggrecan and Sox 9. This data was analyzed using the two-sided Student's t-test. RESULTS and DISCUSSION. In the transgenic group, the number of chondrocytes and GAG production were increased by the LIPUS stimulation in 1 day of culture (Fig. 1,2), and the mRNA expression levels of agrrecan (Fig. 3) and Sox 9 were increased in 2 days of culture. However the mRNA expression level of aggrecan was decreased after 3 days of culture. These LIPUS-derived changes were not found in the wild-type and mixed groups. We previously reported that the adhesive force between chondrocytes and RGD transgenic fibroin surfaces was higher than that for mixed fibroin, suggesting that adhesive force is translated via RGD which bonds covalently to the fibroin proteins for the transgenic group. The present results suggest that the early biological adhesion via RGD on the transgenic fibroin is sensitive to LIPUS