Optimal treatment for symptomatic talus Osteochondral Lesions (OCLs) where primary surgical techniques have failed has not been established. Recent advances have focussed on biological repair such as Autologous Chondrocyte Implantation (ACI) however funding for this treatment is limited. Stem cell therapy in the ankle has not been assessed. The purpose of this pilot study was to evaluate the safety and efficacy of stem cell therapy in the treatment of ankle OCLs. The study was approved by the new procedures committee. Between January 2015 and December 2016, 26 patients, mean age of 36 years (range 16–58 years) with persisting disabling symptoms underwent Complete Cartilage Regeneration (CCR) using stem cells for failed primary treatment for ankle OCLs. Treatment involved iliac crest bone marrow aspiration, centrifugation to obtain bone marrow concentrate (BMC), and then injection of the BMC combined with hyaluronic acid into the OCL. Any necessary additional procedures, e.g. bone grafting or lateral ligament reconstruction were also undertaken. In 18 patients the lesion was on the medial talar dome, in 5 the lateral talar dome, 2 multiple, 1 tibial plafond. The Manchester-Oxford Foot Questionnaire (MOXFQ) was utilised to assess outcome. Average pre-operative MOXFQ scores were Walking dimension −78, Pain dimension − 65, and Social dimension − 64.2. Average 3 month post-operative MOXFQ scores were Walking − 54.8, Pain − 35.4, Social − 38.9. Average 6 month post-operative MOXFQ scores were Walking − 34.4, Pain − 35.4, Social − 28. Two patients from the beginning of the series had AOFAS scores only which improved from an average of 55 pre-operatively to 76 post-operatively. No early complications were noted. We conclude that CCR treatment is a safe treatment for talus OCLs in patients who have failed primary treatment. The procedure avoids two-stage surgery of ACI in some patients without large cysts. The early clinical outcome is favourable with no complications noted. Longer term follow-up is required

Due to unsatisfactory results and reported drawbacks of anterior cruciate ligament (ACL) reconstruction new regenerative approaches based on tissue-engineering strategies are currently under investigation. It was the purpose of this study to determine if a novel silk fiber-based ACL scaffold is able to initiate osteointegration in the femoral and tibial bone tunnels under in vivo conditions. Furthermore we tested if the osteointegration process will be improved by intraoperatively seeding the scaffolds with the autologous stromal vascular fraction, an adipose-derived, stem cell-rich isolate from knee fat pads.

In this controlled laboratory study, 33 sheep underwent ACL resection and were then randomly assigned to 2 experimental groups: ACL reconstruction with a scaffold alone and ACL reconstruction with a cell-seeded scaffold. Half of the sheep in each group were randomly chosen and euthanized 6 months after surgery and the other half at 12 months. To analyze the integration of the silk-based scaffold in the femoral and tibial bone tunnels, hard tissue histology and micro-computed tomography measurements were performed.

The histological workup showed that in all treatment groups, with or without the application of the autologous stromal vascular fraction, an interzone of collagen fibers had formed between bone and silk-based graft. This collagen-fiber continuity partly consisted of Sharpey fibers, comparable with tendon-bone healing known for autografts and allografts. Insertion sites were more broad based at 6 months and more concentrated on the slightly protruding, bony knoblike structures at 12 months. Histologically, no differences between the treatment groups were detectable. Analysis of micro-computed tomography measurements revealed a significantly higher tissue density for the cell-seeded scaffold group as compared with the scaffold-alone group in the tibial but not femoral bone tunnel after 12 months of implantation.

The novel silk fiber-based scaffold for ACL regeneration demonstrated integration into the bone tunnels via the formation of a fibrous interzone similar to allografts and autografts. Histologically, additional cell seeding did not enhance osteointegration. No significant differences between 6 and 12 months could be detected. After 12 months, there was still a considerable amount of silk present, and a longer observation period is necessary to see if a true ligament-bone enthesis will be formed.

The zonal organization of articular cartilage is crucial in providing the tissue with mechanical properties to withstand compression and shearing force. Current treatments available for articular cartilage injury are not able to restore the hierarchically organized architecture of the tissue. Implantation of zonal chondrocyte as a multilayer tissue construct could overcome the limitation of current treatments. However, it is impeded by the lack of efficient zonal chondrocyte isolation protocol and dedifferentiation of chondrocytes during expansion on tissue culture plate (TCP). This study aims to develop a protocol to produce an adequate number of high-quality zonal chondrocytes for clinical application via size-based zonal chondrocyte separation using inertial spiral microchannel device and expansion under dynamic microcarrier culture.

Full thickness (FT) chondrocytes isolated from porcine femoral condyle cartilage were subjected to two serial of size-based sorting into three subpopulations of different cell sizes, namely small (S1), medium (S2), and large (S3) chondrocytes. Zonal phenotype of the three subpopulations was characterised. To verify the benefit of stratified zonal chondrocyte implantation in the articular cartilage regeneration, a bilayer hydrogel construct composed of S1 chondrocytes overlaying a mixture of S2 and S3 (S2S3) chondrocytes was delivered to the rat osteochondral defect model. For chondrocyte expansion, two dynamic microcarrier cultures, sort-before-expansion and sort-after-expansion, which involved expansion after or before zonal cells sorting, were studied to identify the best sort-expansion strategy.

Size-sorted zonal chondrocytes showed zone-specific characteristics in qRT-PCR with a high level of PRG4 expression in S1 and high level of aggrecan, Type II and IX collagen expression in S2 and S3. Cartilage reformation capability of sorted zonal chondrocytes in three-dimensional fibrin hydrogel showed a similar trend in qRT-PCR, histology, extracellular matrix protein quantification and mechanical compression test, indicating the zonal characteristics of S1, S2 and S3 as superficial (SZ), middle (MZ) and deep (DZ) zone chondrocytes, respectively. Implantation of bilayered zonal chondrocytes resulted in better cartilage tissue regeneration in a rat osteochondral defect model than FT control group, with predominantly Type II hyaline cartilage tissue and significantly lower Type I collagen. Dynamic microcarrier expansion of sorted zonal chondrocytes was able to retain the zonal cell size difference that correlate to zonal phenotype, while maintaining the rounded chondrocyte morphology and F-actin distribution similar to that in mature articular cartilage. With the better retention of zonal cell size and zonal phenotype relation on microcarrier, zonal cells separation was achievable in the sort-after-expansion strategy with cells expanded on microcarrier, in comparison to cells expanded on TCP.

Inertial spiral microchannel device provides a label-free and high throughput method to separate zonal chondrocytes based on cell size. Stratified implantation of zonal chondrocytes has the potential to improve articular cartilage regeneration. Dynamic microcarrier culture allows for size-based zonal chondrocyte separation to be performed on expanded chondrocytes, thus overcoming the challenge of limited tissue availability from the patients. Our novel zonal chondrocyte isolation and expansion protocol provide a translatable strategy for stratified zonal chondrocyte implantation that could improve articular cartilage regeneration of critical size defects.

Adult articular cartilage mechanical functionality is dependent on the unique zonal organization of its tissue. Current mesenchymal stem cell (MSC)-based treatment has resulted in sub-optimal cartilage repair, with inferior quality of cartilage generated from MSCs in terms of the biochemical content, zonal architecture and mechanical strength when compared to normal cartilage. The phenotype of cartilage derived from MSCs has been reported to be influenced by the microenvironmental biophysical cues, such as the surface topography and substrate stiffness. In this study, the effect of nano-topographic surfaces to direct MSC chondrogenic differentiation to chondrocytes of different phenotypes was investigated, and the application of these pre-differentiated cells for cartilage repair was explored.

Specific nano-topographic patterns on the polymeric substrate were generated by nano-thermal imprinting on the PCL, PGA and PLA surfaces respectively. Human bone marrow MSCs seeded on these surfaces were subjected to chondrogenic differentiation and the phenotypic outcome of the differentiated cells was analyzed by real time PCR, matrix quantification and immunohistological staining. The influence of substrate stiffness of the nano-topographic patterns on MSC chondrogenesis was further evaluated. The ability of these pre-differentiated MSCs on different nano-topographic surfaces to form zonal cartilage was verified in in vitro 3D hydrogel culture. These pre-differentiated cells were then implanted as bilayered hydrogel constructs composed of superficial zone-like chondro-progenitors overlaying the middle/deep zone-like chondro-progenitors, was compared to undifferentiated MSCs and non-specifically pre-differentiated MSCs in a osteochondral defect rabbit model.

Nano-topographical patterns triggered MSC morphology and cytoskeletal structure changes, and cellular aggregation resulting in specific chondrogenic differentiation outcomes. MSC chondrogenesis on nano-pillar topography facilitated robust hyaline-like cartilage formation, while MSCs on nano-grill topography were induced to form fibro/superficial zone cartilage-like tissue. These phenotypic outcomes were further diversified and controlled by manipulation of the material stiffness. Hyaline cartilage with middle/deep zone cartilage characteristics was derived on softer nano-pillar surfaces, and superficial zone-like cartilage resulted on softer nano-grill surfaces. MSCs on stiffer nano-pillar and stiffer nano-grill resulted in mixed fibro/hyaline/hypertrophic cartilage and non-cartilage tissue, respectively. Further, the nano-topography pre-differentiated cells possessed phenotypic memory, forming phenotypically distinct cartilage in subsequent 3D hydrogel culture. Lastly, implantation of the bilayered hydrogel construct of superficial zone-like chondro-progenitors and middle/deep zone-like chondro-progenitors resulted in regeneration of phenotypically better cartilage tissue with higher mechanical function.

Our results demonstrate the potential of nano-topographic cues, coupled with substrate stiffness, in guiding the differentiation of MSCs to chondrocytes of a specific phenotype. Implantation of these chondrocytes in a bilayered hydrogel construct yielded cartilage with more normal architecture and mechanical function. Our approach provides a potential translatable strategy for improved articular cartilage regeneration using MSCs.

Injured skeletal muscle repairs spontaneously via regeneration, however, this process is often incomplete because of fibrotic tissue formation. In our study we wanted to show improved efficiency of regeneration process induced by antifibrotic agent decorin in a combination with Platelet Rich Plasma (PRP)-derived growth factors. A novel human myoblast cell (hMC) culture, defined as CD56 (NCAM)+ developed in our laboratory, was used for evaluation of potential bioactivity of PRP and decorin. To determine the their effect on the viability of hMC we performed a MTT assay. To perform the cell proliferation assay, hMCs were separately seeded on plates at a concentration of 30 viable cells per well. Cell growth medium prepared with different concentrations of PRP exudates (5%, 10%, and 20%) and decorin (10 ng/mL, 25 ng/mL, and 50 ng/mL) were added and incubated for 7 days. After incubation we stained the cells with crystal-violet and measured the absorbance.

To study the expression of Transforming Growth Factor Beta (TGF-β) and myostatin (MSTN), two main fibrotic factors in the process of muscle regeneration we performed several ELISA assays in groups treated with all therapeutic agents (PRP, decorin and their combination). Further, we have studied the ability of these agents to influence the differential cascade of dormant myoblasts towards fully differentiated myotubes by monitoring step wise activation of single nuclear factors like MyoD and Myogenin via multicolor flow cytometry. We stained the cells simultaneously with antibodies against CD56, MyoD and myogenin. We acquired cell images of 5,000 events per sample at 40 x magnification using 488 nm and 658 nm lasers and fluorescence was collected using three spectral detection channels. We analysed the cells populations according to expression of single or multiple markers and their ratios.

Finally, we examined the treated cell populations using a multicolour laser microscope after staining for desmin (a key marker of myogenic differentiation of hMC), α-tubulin, and nuclei. Optical images were acquired at the center of chamber slides where the cell density is at its highest using a Leica TCS SP5 II confocal microscope and analysed using Photoshop CS6, where a “Color Range” tool was used in combination with a histogram palette to count the pixels that correspond to desmin-positive areas in an image.

The mitochondrial activity of cells, as determined by the MTT assay, was significantly increased (p < 0 .001) after exposure to tested concentrations of PRP exudate. Similarly, viability was elevated in all tested concentrations of decorin. PRP exudate enhanced the viability of cells to more than 400% when compared to the control (p < 0 .001). The viability of cells treated with PRP exudates was also significantly higher when compared to decorin (p < 0 .001). Decorin did not show a significant effect on cell proliferation compared to the control, however, cultivation with PRP exudate leads to a 5-fold increase in cell proliferation (p < 0 .001). Decorin was shown to down-regulate the expression of TGF-β when compared to the control by more than 15% (p < 0 .001) but significantly less than PRP exudate p < 0 .005). PRP significantly down-regulated TGF-β expression by more than 30% (p < 0 .001). Similarly, the MSTN expression levels were significantly down-regulated by decorin and PRP. MSTN levels of cells treated with decorin were decreased by 28.4% (p < 0 .001) and 23.1% by PRP (p < 0 .001) when compared to the control group.

Using flow cytometry we detected a 39.1% increase in count of myogenin positive cells in the PRP-treated group compared to the control. Moreover, there was a 3.09% increase in cells positive only for myogenin, whereas no such cells were found in the control cell population. The population of cells positive only for myogenin is considered as fully differentiated and capable of fusion into myotubes as well as future mucle fibers and is thus of great importance for muscle regeneration. At the same time 20.6% fewer cells remained quiescent (positive only for CD56). Cells positive for both MyoD and myogenin represent the population that shifted significantly towards mature myocites during myogenesis but are not yet fully committed.

Finally, a statistically significant up-regulation of desmin expression (p < 0 .01 for the PRP treated group, p < 0 .005 for the decorin and PRP + decorin treated groups) was present in all therapeutic groups when compared to the control. While no significant difference was found between the PRP and decorin-treated groups, their combination led to a more than 3-fold increase (p < 0 .005) of desmin expression when compared to single bioactives.

PRP can be a highly potential therapeutic agent for skeletal muscle regeneration and repair, especially if in combination with a TGF-β antagonis decorin. Achieving better healing could likely result in faster return to play and lower reinjury rate.

Osteochondral (OC) defects of the knee are associated with pain and significant limitation of activity. Studies have demonstrated the therapeutic efficacy of mesenchymal stem cell (MSC) therapies in treating osteochondral defects. There is increasing evidence that the efficacy of MSC therapies may be a result of the paracrine secretion, particularly exosomes. Here, we examine the effects of MSC exosomes in combination with Hyaluronic Acid (HA) as an injectable therapy on functional osteochondral regeneration in a rabbit osteochondral defect model.

Exosomes were purified from human MSC conditioned medium by size fractionation. A circular osteochondral defect of 4.5 mm diameter and 2.5 mm depth was surgically created in the trochlear grooves of 16 rabbit knees. Thereafter, eight knees received three weekly injections of 200 µg of exosomes in one ml of 3% HA, and the remaining eight knees received three weekly injections of one ml of 3% HA only. The rabbits were sacrificed at six weeks. Analyses were performed by macroscopic and histological assessments, and functional competence was analysed via Young Modulus calculation at five different points (central, superior, inferior, medial and lateral) of the repaired osteochondral defect site.

MSC exosomes displayed a modal size of 100 nm and expressed exosome markers (CD81, TSG101 and ALIX). When compared to HA alone, MSC exosomes in combination with HA showed significantly better repair histologically and biomechanically. The Young Modulus was higher in 4 out of the 5 points. In the central region, the Young Modulus of MSC exosome and HA combination therapy was significantly higher: 5.42 MPa [SD=1.19, 95% CI: 3.93–6.90] when compared to HA alone: 2.87 MPa [SD=2.10, 95% CI: 0.26–5.49], p < 0 .05. The overall mean peripheral region was also significantly higher in the MSC exosome and HA combination therapy group: 5.87 MPa [SD=1.19, 95% CI: 4.40–7.35] when compared to HA alone: 2.70 MPa [SD=1.62, 95% CI: 0.79–4.71], p < 0 .05. The inferior region showed a significantly higher Young Modulus in the combination therapy: 7.34 MPa [SD=2.14, 95% CI: 4.68–10] compared to HA alone: 2.92 MPa [SD=0.98, 95% CI: 0.21–5.63], p < 0.05. The superior region showed a significantly higher Young Modulus in the combination therapy: 7.31 MPa [SD=3.29, 95% CI: 3.22–11.39] compared to HA alone: 3.59 MPa [SD=2.55, 95% CI: 0.42–6.76], p < 0.05. The lateral region showed a significantly higher Young Modulus in the combination therapy: 8.05 MPa [SD=2.06, 95% CI: 5.49–10.61] compared to HA alone: 3.56 MPa [SD=2.01, 95% CI: 1.06–6.06], p < 0.05. The medial region showed a higher Young Modulus in the combination therapy: 6.68 MPa [SD=1.48, 95% CI: 4.85–8.51] compared to HA alone: 3.45 MPa [SD=3.01, 95% CI: −0.29–7.19], but was not statistically significant. No adverse tissue reaction was observed in all the immunocompetent animals treated with MSC exosomes.

Three weekly injections of MSC exosomes in combination with HA therapy results in a more functional osteochondral regeneration as compared to HA alone.

Millions of medical devices made of synthetic or modified natural materials all trigger a similar reaction—the foreign body reaction. Biocompatibility, for materials that pass routine cytoxicity assays, is largely associated with a mild foreign body reaction. I.e. a thin, avacular, collagenous, non-adherent foreign body capsule. The implant is incorporated into a dead-zone of acellular scar. The contemporary tissue engineering paradigm would suggest that synthetic polymers and scaffolds lacking cellular, biomolecule or biomimetic elements will give this same fibrotic, avascular healing reaction.

In this talk, a synthetic biomaterial will be described that readily integrates into tissue and may stimulate spontaneous reconstruction of tissue. The material is fabricated by a process called sphere-templating and it can be made from many synthetic polymers including hydrogels, silicones and polyurethanes. All pores are identical in size and interconnected. Studies from our group have shown optimal healing (as suggested by extensive vascularity and minimal fibrosis) for spherical pores of 30–40 m size. The integrative healing noted is independent of biomaterial. Similar results are observed with sphere-templated silicone rubber and pHEMA hydrogel. In addition, surface chemical modification of the hydrogel with carbonyl diimidazole, or immobilisation on the hydrogel of collagen I or laminin did not change the healing response.

Also, good healing results have been seen upon implantation in skin (subcutaneous, percutaneous), heart muscle, sclera, skeletal muscle, bone and vaginal wall. We consistently find the pore spaces heavily populated by monocytic cells that stain for macrophage cell surface markers. However, at long implantation times (16 or more weeks), the ability to stain for macrophage surface markers decreases. It could be possible that these cells populating the implants are differentiating into other tissues. Thus, such materials may represent a path to cell-free tissue engineering. Others have seen similar healing results, via completely different materials strategies, generally involving biological molecules. The in vivo results from our group and related results from other groups suggest we are on the cusp of a revolution in healing, biomaterials integration and tissue reconstruction. Also, the boundaries between biomaterials and tissue engineering continue to blur.

Autologous cell therapy using stem cells and progenitor cells is considered to be a popular approach in regenerative medicine for the repair and regeneration of tissue and organs. In orthopaedic practice, autologous cell therapy has become a major focus, particularly, as a feasible treatment for tendon injury.

Tendons are dense connective tissue that bridge bone to muscle and transmit forces between muscle and bone to maintain mechanical movement. Tendons are poorly vascularised and have very little capacity to self-regenerate. Degeneration of tendon is often caused by injury. The pathogenesis of tendon injury, commonly known as tendinosis, is not an inflammatory condition but is secondary to degenerative changes, including disruption of the collagen matrix, calcification, vascularisation and adipogenesis. The aetiology of tendinosis is considered to be multifactorial and the pathogenesis is still unclear. Intrinsic factors such as a lack of blood and nutrition supply and extrinsic factors such as acute trauma and overuse injury caused by repetitive strain, have been implicated as contributors to the pathogenesis of tendinosis. More recent studies suggest that programmed tendon cell death (tenocyte apoptosis) may play a major role in the development of tendinosis. Such cellular abnormalities may influence the capacity of tendon to maintain its integrity.

Traditional treatments such as anti-inflammatory drugs, steroid injections and physiotherapy are aimed at symptom relief and do not address the underlying pathological changes of degeneration. Here, we propose that autologous cell therapy may be an innovative and promising treatment for tendon injury. We will present evidence that suggest that autologous tendon cell therapy may be feasible to repair and regenerate tendon.

We will also present data summarising the preclinical evaluation of autologous tendon cell therapy in animal models and the safety and tolerability of autologous tendon cell therapy in humans in studies, which are currently conducted at the Centre for Orthopaedic Research at the University of Western Australia.

Excellent reconstruction of bone will be described induced by a synthetic biomaterial without a calcium phosphate mineral phase or growth factors, and with a pore size of 35 m. The material is fabricated by a process called sphere-templating and it can be made from many synthetic materials including hydrogels, silicones, polyurethanes and glasses. All pores are identical in size and interconnected. Studies from our group have shown optimal healing in soft tissue (as suggested by extensive vascularity and minimal fibrosis) for spherical pores of 30–40 m size. Sphere-templated hydrogel implants in bone were performed using the following procedure: Under appropriate anesthesia, 18–24month old NZW rabbits underwent medial parapatellar arthrotomy, with exposure of the medial femoral condyle. A 3.5 mm end-cutting drill, locked in a rigid armature, was used to create a host graft site at the center of the articular cartilage lesion, with depth of cut matched to the sphere-templated construct thickness of 2 mm. Animals were sacrificed at one day, 28 days, and 12 weeks. After sacrifice, the femora were isolated and the condyles dissected. Condyles were fixed in 4% paraformaldehyde at 4°C for 48 hrs, decalcified in Immunocal for 14 days at 4°C and paraffin embedded. Specimens were sectioned to a thickness and stained with Safranin- O/Fast Green, hematoxylin/eosin or Masson's trichrome. Prior to decalcification, selected samples were evaluated by micro-CT utilising a Skyscan 1076 microCT low dose in-vivo X-ray scanner, slice imaging and 3D image reconstruction. Both histologically, and with micro-CT imaging, excellent tissue and mineral reconstruction was observed in the sphere templated material. The contralateral control, drilled but without implant, showed essentially no reconstruction.

Since the classical paradigm for bone reconstruction requires either autologous bone, cadaver bone, or calcium phosphate scaffolds with pores >150 microns, the healing observed here suggests new avenues for bone regeneration.

Gene-activated scaffolds have shown potential in localised gene delivery resulting in bone tissue regeneration. In this study, the ability of two gene delivery vectors, polyethyleneimine (PEI) and nano-hydroxyapatite (nHA), to act as carriers for the delivery of therapeutic genes when combined with our collagen-nHA (coll-nHA) scaffolds to produce gene-activated scaffolds [1, 2], was determined. In addition, coll-nHA-dual gene scaffolds containing both an angiogenic gene and an osteogenic gene were assessed for bone healing in an in vivo Wistar rat calvarial defect model. When cells were applied to the coll-nHA scaffolds under osteogenic conditions in vitro, the dual scaffolds exhibited significantly superior osteogenic potential when analysed using microCT, calcium quantification and histology compared to single-gene scaffolds and gene-free controls. When the dual scaffolds were assessed in vivo, the nHA dual scaffold outperformed all other groups as early as 4 weeks post-implantation as determined using X-ray, microCT, quantification of new bone volume, histology and vessel formation. This research has demonstrated the potential of using novel coll-nHA scaffolds for therapeutic gene therapy while also being capable of simultaneously delivering numerous genes. This study underlines the effect of specifically tailoring gene-activated scaffolds for bone regeneration applications.

Biomaterials used in regenerative medicine should be able to support and promote the growth and repair of natural tissues. Bioactive glasses (BGs) have a great potential for applications in bone tissue engineering [1, 2]. As it is well known BGs can bond to host bone and stimulate bone cells toward osteogenesis. Silicate BGs, e.g. 45S5 Bioglass® (composition in wt.%: 45 SiO₂, 6 P₂O₅, 24, 5 Na₂O and 24.5 CaO), exhibit positive characteristics for bone engineering applications considering that reactions on the material surface induce the release of critical concentrations of soluble Si, Ca, P and Na ions, which can lead to the up regulation of different genes in osteoblastic cells, which in turn promote rapid bone formation. BGs are also increasingly investigated for their angiogenic properties.

This presentation is focused on cell behavior of osteoblast-like cells and osteoclast-like cells on BGs with varying sample geometry (including dense discs for material evaluation and coatings of highly porous Al₂O₃-scaffolds as an example of load-bearing implants). To obtain mechanically competent porous samples with trabecular architecture analogous to those of cancellous bone, in this study Al₂O₃ scaffolds were fabricated by the well-known foam replication method and coated with Bioglass® by dip coating.

The resulted geometry and porosity were proven by SEM and μCT. Originating from peripheral blood mononuclear cells formed multinucleated giant cells, i.e. osteoclast-like cells, after 3 weeks of stimulation with RANKL and M-CSF. Thus, the bioactive glass surface can be considered a promising material for bone healing, providing a surface for bone remodeling. Osteoblast-like cells and bone marrow stromal cells were seeded on dense bioactive glass substrates and coatings showing an initial inhibited cell attachment but later a strong osteogenic differentiation. Additionally, cell attachment and differentiation studies were carried out by staining cytoskeleton and measuring specific alkaline phosphatase activity. In this context, 45S5 bioactive glass surfaces can be considered a highly promising material for bone tissue regeneration, providing very fast kinetics for bone-like hydroxyapatite formation (mineralization). Our examinations revealed good results in vitro for cell seeding efficacy, cell attachment, viability, proliferation and cell penetration onto dense and porous Bioglass®-coated scaffolds.

Recent in vivo investigations [3] have revealed also the angiogenic potential of bioactive glass both in particulate form and as 3D scaffolds confirming the high potential of BGs for bone regeneration strategies at different scales. Implant surfaces based on bioactive glasses offer new opportunities to develop these advanced biomaterials for the next generation of implantable devices and tissue scaffolds with desired tissue-implant interaction.

INTRODUCTION

The menisci play a fundamental biomechanical role in the knee and also help in the maintaining of the articular homeostasis; thus, either a lesion or the complete absence of the menisci can invalidate the physiological function of the knee causing important damages, even at long term. Unfortunately, meniscal tears are often found during the ordinary orthopaedic practice while the regenerative potential of this kind of tissue is very low and limited to its peripheral-vascularized part; this is why the majority of these common arthroscopic findings are not reparable and often the surgeon is almost forced to perform a partial, subtotal or even total meniscectomy, regardless of the well-known consequences of this kind of surgery.

Subchondral drillings for articular cartilage defects usually result in fibrocartilage repair, which is inferior biomechanically compared to hyaline cartilage. We postulate that intra-articular injections with autologous marrow-derived stem cells (MSC) and hyaluronic acid (HA) can improve the quality of repair cartilage.

We tested this hypothesis in a goat model by creating an articular cartilage defect in the stifle joint and conducted subchondral drillings. The animals were divided into three groups: Group A (control) no injections, Group B (HA) weekly injection of 1 ml sodium hyaluronate for three weeks, Group C (HA+MSC) similar to Group B but with 2 mls autologous MSC in addition to HA. MSC were obtained by bone marrow aspiration, centrifuged, and divided into aliquots, which were cryopreserved. Fifteen animals were equally divided between the groups and sacrificed at 24 weeks after surgery where the joint was harvested and examined macroscopically and histologically.

Of the 15 animals, two had died in Group A and one was excluded from Group C due to an infection. In Group A, repair constituted mainly of scar tissue, while in Group B, there was less scar tissue, with small amounts of proteoglycan and collagen II at the osteochondral junction. In contrast, repair cartilage from Group C animals demonstrated almost complete coverage of the defect with evidence of hyaline cartilage regeneration. Histology as assessed by Gill scoring was significantly better in Group C with one-way ANOVA giving an F-statistic of 10.611 with a p-value of 0.004, which was highly significant.

Post-operative intra-articular injections of autologous MSC in combination with HA following subchondral drillings into chondral defects resulted in better cartilage repair.

Articular cartilage repair remains a challenge in orthopedic surgery, as none of the current clinical therapies can regenerate the functional hyaline cartilage tissue. In this study, we proposed a one-step surgery strategy that uses autologous bone marrow mesenchymal stem cells (MSCs) embedded in type II collagen (Col-II) gels to repair the full thickness chondral defects in minipig models. Briefly, 8 mm full thickness chondral defects were created in both knees separately, one knee received Col-II + MSCs transplantation, while the untreated knee served as control. At 1, 3 and 6 months postoperatively, the animals were sacrificed, regenerated tissue was evaluated by magnetic resonance imaging, macro- and microscopic observation, and histological analysis. Results showed that regenerated tissue in Col-II + MSCs transplantation group exhibited significantly better structure compared with that in control group, in terms of cell distribution, smoothness of surface, adjacent tissue integration, Col-II content, structure of calcified layer and subchondral bone. With the regeneration of hyaline-like cartilage tissue, this one step strategy has the potential to be translated into clinical application.

Subchondral drillings for articular cartilage repair give functional improvement that peaks at 24 months after surgery. We postulate that intra-articular injections with autologous peripheral blood stem cells (PBSC) and hyaluronic acid (HA) following subchondral drillings can improve the repair process.

Thirty-four patients with full thickness chondral defects of the knee joint underwent subchondral drillings. The operated knees were then placed on continuous passive motion for a period of two hours per day for four weeks, with partial weight-bearing for the first six weeks. PBSC were harvested by apheresis and divided into aliquots which were cryopreserved. One week after surgery, weekly intra-articular injections of 2.5 mLs PBSC mixed with 2 mLs of sodium hyaluronate were given for five weeks after surgery. Patients were followed up for an average of 11 months (range 6–20) and assessed using serial MRI scans. Second look arthroscopy and chondral biopsies were obtained in five patients. International Knee Documentation Committee (IKDC) scores were compared with previous microfractures results from the Mithoefer cohort study using linear interpolation to generate time-based predicted values. The difference was compared using a two-tailed, one-sample T-test against a value of zero.

Serial MRI scans showed healing of subchondral bone and evidence of cartilage regeneration that was confirmed on arthroscopy with good integration into surrounding cartilage with no delamination. Biopsy specimens showed attributes typical of hyaline cartilage with good cellular morphology, abundant proteoglycans and Type II collagen. No oedema or degenerative changes were seen. The IKDC data was on average 12.8 points (95% CI 6.5-19.1) higher than the Mithoefer group with p=0.0002.

Intra-articular injections of PBSC and HA following subchondral drillings resulted in good repair tissue based on MRI, arthroscopic, and histological criteria, with IKDC scores superior to standard microfracture surgery.

Our aim was to accurately determine whether muscle atrophy and fatty infiltration are reversible following cuff repair. Patients with a repairable cuff-tear were recruited and assessed clinically and radiologically (Magnetic Resonance Imaging). At surgery, supraspinatus was biopsied. Post-operatively, patients underwent clinical evaluation at standardised intervals, with further MRI and an ultrasound guided biopsy of supraspinatus at 12 months.

MRI was used to characterize cuff-tears and determine the degree of muscle atrophy and fatty infiltration. Biopsy samples were fixed on-site and transported for processing. Morphometric assessments of myofibres were made and mean cross-sectional areas calculated using validated techniques. The pathologist was blinded to sample details. Statistical analysis was performed to assess differences in mean myofibre area following cuff repair and correlated with radiological findings.

Eight patients were available for completed histological and radiological analysis. Six (two re-tears) demonstrated sizeable and highly statistically significant improvements in mean myofibre cross-sectional area (P=0.000–0.0253). Of the two not showing any increase in myofibre area, neither result was statistically significant (P=0.06, 0.2); one was a re-tear and one was a repair of a partial-thickness tear. Radiologically, the muscle and fatty changes had not demonstrably changed.

Our finding that myofibre cross-sectional area increases following cuff repair suggests muscle atrophy is a potentially reversible process. Even with re-tears, improvements were seen. MRI features of fatty infiltration and muscle atrophy were not seen to improve however. It is likely that radiological assessment is not sensitive enough to demonstrate the reversibility of muscle atrophy seen on histological analysis at one year.

Introduction and aims

Growth plate cartilage is responsible for bone growth in children. Injury to growth plate can often lead to faulty bony repair and bone growth deformities, which represents a significant clinical problem. This work aims to develop a biological treatment.

Painful neuromas may follow traumatic nerve injury. We carried out a double-blind controlled trial in which patients with a painful neuroma of the lower limb (n = 20) were randomly assigned to treatment by resection of the neuroma and translocation of the proximal nerve stump into either muscle tissue or an adjacent subcutaneous vein. Translocation into a vein led to reduced intensity of pain as assessed by visual analogue scale (5.8 (sd 2.7) vs 3.8 (sd 2.4); p < 0.01), and improved sensory, affective and evaluative dimensions of pain as assessed by the McGill pain score (33 (sd 18) vs 14 (sd 12); p < 0.01). This was associated with an increased level of activity (p < 0.01) and improved function (p < 0.01).

Transposition of the nerve stump into an adjacent vein should be preferred to relocation into muscle.