Biosynthetic scaffolds for partial meniscal loss: A systematic review from animal models to clinical practice.

Acute or degenerative meniscus tears are the most common knee lesions. Meniscectomy provides symptomatic relief and functional recovery only in the short- to mid-term follow-up but significantly increases the risk of osteoarthritis. For this reason, preserving the meniscus is key, although it remains a challenge. Allograft transplants present many disadvantages, so during the last 20 years preclinical and clinical research focused on developing and investigating meniscal scaffolds. The aim of this systematic review was to collect and evaluate all the available evidence on biosynthetic scaffolds for meniscus regeneration both in vivo and in clinical studies. Three databases were searched: 46 in vivo preclinical studies and 30 clinical ones were found. Sixteen natural, 15 synthetic, and 15 hybrid scaffolds were studied in vivo. Among them, only 2 were translated into clinic: the Collagen Meniscus Implant, used in 11 studies, and the polyurethane-based scaffold Actifit®, applied in 19 studies. Although positive outcomes were described in the short- to mid-term, the number of concurrent procedures and the lack of randomized trials are the major limitations of the available clinical literature. Few in vivo studies also combined the use of cells or growth factors, but these augmentation strategies have not been applied in the clinical practice yet. Current solutions offer a significant but incomplete clinical improvement, and the regeneration potential is still unsatisfactory. Building upon the overall positive results of these "old" technologies to address partial meniscal loss, further innovation is urgently needed in this field to provide patients better joint sparing treatment options.

Assessing conformal thin film growth under nonstochastic deposition conditions: application of a phenomenological model of roughness replication to synthetic topographic images.

In this work, a simple method to follow the evolution of the surface of thin films during growth on substrates characterised by high roughness is detailed. To account for real cases as much as possible, the approach presented is based on the hypothesis that deposition takes place under nonstochastic conditions, such as those typical of many thin film processes in industry and technology. In this context, previous models for roughness replication, which are mainly based on idealised deposition conditions, cannot be applied and thus ad hoc approaches are required for achieving quantitative predictions. Here it is suggested that under nonstochastic conditions a phenomenological relation can be proposed, mainly based on local roughening of surface, to monitor the statistical similarity between the film and the substrate during growth or, in other words, to detect changes of the bare substrate morphological profile occurring during the film growth on top. Such approximation is based on surface representation in terms of power spectral density of surface heights, derived from topographic images; in this work, such method will be tested on two separate batches of synthetic images which simulate thin films growth onto a real rough substrate. In particular, two growth models will be implemented: the first reproduces the surface profile obtained during an atomic force microscopy measurement by using a simple geometrical envelope of surface, regardless the thin film growth mechanism; the second reproduces the columnar growth expected under nonstochastic deposition conditions. It will be shown that the approach introduced is capable to highlight differences between the two batches and, in the second case, to quantitatively account for the replication of the substrate roughness during growth. The results obtained here are potentially interesting in that they account essentially for the geometrical features of the surfaces, and as such they can be applied to synthetic depositions that reproduce different thin film depositions and experimental contexts.

Thin film deposition onto rough surfaces is widespread among many industrial and technological applications such as photovoltaics, microelectronics, optics and biomedicine just to mention a few. In such cases, compared to substrate morphology, film deposition may be required to improve certain surface functionalities through roughening or smoothing of the pristine substrate morphology to accomplish different needs or applications. This raises a simple and legitimate question: how could the degree of replication of the substrate morphology after film deposition be determined? Quantitative approaches to this issue involve statistical descriptions of the two interfaces in terms of power spectral densities retrieved from scanning probe microscopy images of the surface. However, this requires an in-depth knowledge of the physics behind the process of film formation, leading to a complication in that models providing quantitative predictions for film conformality are based on ideal deposition conditions; thus, numerical results remained so far restricted to the case of atomically flat, and mostly unrealistic, surfaces. To tackle into this subject, an approximation is suggested that is based on phenomenological considerations and on the hypothesis that deposition is nonideal. On these premises, a simple conformality factor derived from a linear relation is introduced to relate the substrate and the evolving film morphology. Such approach is then applied to simulated atomic force microscopy images which describe the film growth onto a real substrate. Two models will be implemented: the first uses a simple geometrical envelope of the surface that uniquely matches with experiments without keeping into account the mechanism of growth, while the second reproduces the columnar growth expected under real deposition conditions. The application of conformality factors to the images so obtained shows that the second model accomplishes well to the final goal of obtaining quantitative results and enables to retrieve quantitative information especially in case of micro or nanometrically structured surfaces.

Emerging Advanced Technologies Developed by IPR for Bio Medical Applications ­.A Review.

Over the last decade, research has intensified worldwide on the use of low-temperature plasmas in medicine and healthcare. Researchers have discovered many methods of applying plasmas to living tissues to deactivate pathogens; to end the flow of blood without damaging healthy tissue; to sanitize wounds and accelerate its healing; and to selectively kill malignant cancer cells. This review paper presents the latest development of advanced and plasma-based technologies used for applications in neurology in particular. Institute for Plasma Research (IPR), an aided institute of the Department of Atomic Energy (DAE), has also developed various technologies in some of these areas. One of these is an Atmospheric Pressure Plasma Jet (APPJ). This device is being studied to treat skin diseases, for coagulation of blood at faster rates and its interaction with oral, lung, and brain cancer cells. In certain cases, in-vitro studies have yielded encouraging results and limited in-vivo studies have been initiated. Plasma activated water has been produced in the laboratory for microbial disinfection, with potential applications in the health sector. Recently, plasmonic nanoparticle arrays which allow detection of very low concentrations of chemicals is studied in detail to allow early-stage detection of diseases. IPR has also been developing AI-based software called DeepCXR and AIBacilli for automated, high-speed screening and detection of footprints of tuberculosis (TB) in Chest X-ray images and for recognizing single/multiple TB bacilli in sputum smear test images, respectively. Deep Learning systems are increasingly being used around the world for analyzing electroencephalogram (EEG) signals for emotion recognition, mental workload, and seizure detection.

How cartilage status can be related to joint loads in anterior cruciate ligament reconstruction: a preliminary analysis including MRI t2 mapping and joint biomechanics.

The knee is the largest and most complex joint in the human body. Traumatic events, such as anterior cruciate ligament (ACL) tear, can lead to an alteration of joint tissues homeostasis. Literature reports an evident correlation between abnormal joint biomechanics and the status of articular tissues. These alterations, due to a sub-optimal ACL reconstruction, may result in an increasing risk of developing degenerative pathologies, such as osteoarthritis. Thus, the identification of the optimal surgical technique is a highly demanding issue in ACL reconstruction. The aim of this study was to analyze the correlation between joint cartilage conditions and knee biomechanics in ACL reconstructions, by integrating MRI T2 mapping investigations, radiostereophotogrammetry-based gait analysis and subject-specific musculoskeletal modelling.

Effects of working gas pressure on zirconium dioxide thin film prepared by pulsed plasma deposition: roughness, wettability, friction and wear characteristics.

In joint arthroplasty one of the main issues related to the failure of prosthetic implants is due to the wear of the ultra-high molecular weight polyethylene (UHMWPE) component. Surface treatments and coatings have been recognized as enhancing methods, able to improve the tribological properties of the implants. Therefore, the main objective of this work was to investigate the possibility to fabricate yttria-stabilized zirconia (YSZ) coatings on a metal (AISI 316-L) substrate by means of Pulsed Electron Deposition, in order to improve the tribological behavior of the polymer-metal coupling, by reducing the initial wear of the UHMWPE component. In order to optimize the coating characteristics, the effects of working gas pressure on both its morphological and tribological properties were analyzed. Morphological characterization of the films was evaluated by Atomic Force Microscopy (AFM). Coating wettability was also estimated by contact angle (CA) measurement. Tribological performance (coupling friction and wear of UHMWPE) was evaluated by using a ball-on-disc tribometer during highly-stressing tests in dry and lubricated (i.e. NaCl and serum) conditions; friction and wear were specifically evaluated at the initial sliding distances - to highlight the main effect of coating morphology - and after 100m - where the influence of the intrinsic materials properties prevails. AFM analysis highlighted that the working pressure heavily affected the morphological characteristics of the realized films. The wettability of the coating at the highest and lowest deposition pressures (CA ~ 60°, closed to substrate value) decreased for intermediate pressures, reaching a maximum CA of ~ 90°. Regarding tribological tests, a strong correlation was found in the initial steps between friction coefficient and wettability, which decreased as the distance increased. Concerning UHMWPE wear associated to coated counterpart, at 100m a reduction rate of about 7% in dry, 12% in NaCl and 5% in presence of serum was obtained compared to the uncoated counterpart. Differently from what highlighted for friction, no correlation was found between wear rate and morphological parameters. These findings, in agreement with literature, underlined the effect of the deposition pressure on the morphological properties, but suggested that physical characteristics are influenced too. Further research on the deposition process will be required in order to improve the tribological performance of the coating at long distances, addressing - above all - orthopedic applications.

Tribological characterization of zirconia coatings deposited on Ti6Al4V components for orthopedic applications.

One of the most important issues leading to the failure of total joint arthroplasty is related to the wear of the plastic components, which are generally made of ultra high molecular weight polyethylene (UHMWPE). Therefore, the reduction of joint wear represents one of the main challenges the research in orthopedics is called to address nowadays. Surface treatments and coatings have been recognized as innovative methods to improve tribological properties, also in the orthopedic field. This work investigated the possibility to realize hard ceramic coatings on the metal component of a prosthesis, by means of Pulsed Plasma Deposition, in order to reduce friction and wear in the standard coupling against UHMWPE. Ti6Al4V substrates were coated with a 2 µm thick yttria-stabilized zirconia (YSZ) layer. The mechanical properties of the YSZ coatings were assessed by nanoindentation tests performed on flat Ti6Al4V substrates. Tribological performance was evaluated using a ball-on-disk tribometer in dry and lubricated (i.e. with fetal bovine serum) highly-stressing conditions, up to an overall distance of 10 km. Tribology was characterized in terms of coefficient of friction (CoF) and wear rate of the UHMWPE disk. After testing, specimens were analyzed through optical microscopy and SEM images, in order to check the wear degradation mechanisms. Progressive loading scratch tests were also performed in dry and wet conditions to determine the effects of the environment on the adhesion of the coating. Our results supported the beneficial effect of YSZ coating on metal components. In particular, the proposed solution significantly reduced UHMWPE wear rate and friction. At 10 km of sliding distance, a wear rate reduction of about 18% in dry configuration and of 4% in presence of serum, was obtained by the coated group compared to the uncoated group. As far as friction in dry condition is concerned, the coating allowed to maintain low CoF values until the end of the tests, with an overall difference of about 40% compared to the uncoated balls. In wet conditions, the friction values were found to be comparable between coated and uncoated materials, mainly due to a premature delamination of the coating. Scratch tests in wet showed in fact a reduction of the critical load required to a complete delamination due to a formation of blister, although no change or damage occurred at the coating during the soaking period. Although conditions of high values of contact pressure were considered, further analyses are however required to fully understand the behavior of YSZ coatings in wet environment and additional research on the deposition process will be mandatory in order to improve the coating tribological performance at long distances addressing orthopedic applications.

Optimizing thickness of ceramic coatings on plastic components for orthopedic applications: A finite element analysis.

Realizing hard ceramic coatings on the plastic component of a joint prosthesis can be strategic for the mechanical preservation of the whole implant and to extend its lifetime. Recently, thanks to the Plasma Pulsed Deposition (PPD) method, zirconia coatings on ultra-high molecular weight polyethylene (UHMWPE) substrates resulted in a feasible outcome. Focusing on both the highly specific requirements defined by the biomedical application and the effective possibilities given by the deposition method in the perspectives of technological transfer, it is mandatory to optimize the coating in terms of load bearing capacity. The main goal of this study was to identify through Finite Element Analysis (FEA) the optimal coating thickness that would be able to minimize UHMWPE strain, possible insurgence of cracks within the coating and stresses at coating-substrate interface. Simulations of nanoindentation and microindentation tests were specifically carried out. FEA findings demonstrated that, in general, thickening the zirconia coating strongly reduced the strains in the UHMWPE substrate, although the 1 µm thickness value was identified as critical for the presence of high stresses within the coating and at the interface with the substrate. Therefore, the optimal thickness resulted to be highly dependent on the specific loading condition and final applications.

Modifying bone scaffold architecture in vivo with permanent magnets to facilitate fixation of magnetic scaffolds.

The fundamental elements of tissue regeneration are cells, biochemical signals and the three-dimensional microenvironment. In the described approach, biomineralized-collagen biomaterial functions as a scaffold and provides biochemical stimuli for tissue regeneration. In addition superparamagnetic nanoparticles were used to magnetize the biomaterials with direct nucleation on collagen fibres or impregnation techniques. Minimally invasive surgery was performed on 12 rabbits to implant cylindrical NdFeB magnets in close proximity to magnetic scaffolds within the lateral condyles of the distal femoral epiphyses. Under this static magnetic field we demonstrated, for the first time in vivo, that the ability to modify the scaffold architecture could influence tissue regeneration obtaining a well-ordered tissue. Moreover, the association between NdFeB magnet and magnetic scaffolds represents a potential technique to ensure scaffold fixation avoiding micromotion at the tissue/biomaterial interface.

Innovative magnetic scaffolds for orthopedic tissue engineering.

The use of magnetism in tissue engineering is a very promising approach, in fact magnetic scaffolds are able not only to support tissue regeneration, but they can be activated and work like a magnet attracting functionalized magnetic nanoparticles (MNPs) injected close to the scaffold enhancing tissue regeneration. This study aimed to assess the in vivo biocompatibility and osteointegrative properties of novel magnetic scaffolds. Two hydroxyapatite/collagen (70/30 wt %) magnetic scaffolds were magnetized with two different techniques: direct nucleation of biomimetic phase and superparamagnetic nanoparticles (MNPs) on self-assembling collagen fibers (MAG-A) and scaffold impregnation in ferro-fluid solution (MAG-B). Magnetic scaffolds were implanted in rabbit distal femoral epiphysis and tibial mid-diaphysis. Histopathological screening showed no inflammatory reaction due to MNPs. Significantly higher bone healing rate (ΔBHR) results were observed in MAG-A in comparison to MAG-B. Significant differences were also found between experimental times with an increase in ΔBHR from 2 to 4 weeks for both scaffolds in trabecular bone, while only for MAG-B (23%, p < 0.05) in cortical bone. The proposed magnetic scaffolds seem to be promising for magnetic guiding in orthopedic tissue engineering applications and they will be suitable to treat also several pathologies in regenerative medicine area.

Anatomic double-bundle and over-the-top single-bundle with additional extra-articular tenodesis: an in vivo quantitative assessment of knee laxity in two different ACL reconstructions.

PURPOSE: Combinations of intra- and extra-articular procedures have been proposed for anterior cruciate ligament reconstruction with the aim of achieving an optimal control of translational and rotational knee laxities. Recently, the need for better reproducing the structural and functional behavior of the native anterior cruciate ligament led to the definition of anatomic double-bundle surgical approach. This study aimed to quantitatively verify whether the in vivo static and dynamic behavior obtained using over-the-top single-bundle with extra-articular tenodesis reconstruction was comparable to the results achieved by anatomic double-bundle approach. METHODS: Thirty-five consecutive patients, with an isolated anterior cruciate ligament injury, were included in the study. Standard clinical laxities and pivot-shift test were quantified before and after anterior cruciate ligament reconstruction by means of a surgical navigation system dedicated to kinematic assessment; displacements of medial and lateral compartment during stress tests were also analyzed. RESULTS: Single-bundle with extra-articular tenodesis approach presented statistically better laxity reduction in varus/valgus stress test at full extension and in internal/external rotation at 90° of flexion; lateral plasty controlled better the lateral compartment during drawer test and varus/valgus stress test both at 0° and 30° of flexion and both the compartments during internal/external rotation at 90° of flexion. On the other hand, pivot-shift phenomenon was better controlled by anatomic double-bundle reconstruction. CONCLUSIONS: Both the reconstructions worked similarly for static knee laxity. The extra-articular procedure played an important role in better constraining the displacement of lateral tibial compartment, whereas the anatomic double-bundle reconstruction better restored the dynamic behavior of knee joint highlighted under pivot-shift stress test. STUDY DESIGN: Case series.

Vascularity and neuroreceptors of the pes anserinus: anatomic study.

The primary aim of this work was to evaluate the neurovascular network of the pes anserinus (PA) at its tibial insertion because the PA is often used for anterior cruciate ligament (ACL) reconstruction. Four fresh cadaver knees were injected with India ink gelatin solution and the arteries that supply blood to the PA were identified; microscopic studies of vessels and nerve fibers were also performed. Superficial and deep branches of the inferior medial genicular artery contribute to an arterial arch that courses deep to the PA insertion. A widespread array of small vessels and nerve fibers penetrate the PA insertion and course along the length of the gracilis and semitendinosus tendons. Computer analysis revealed that the mean diameter of the vessels decreased from 2201 microm at the insertion to 661 microm midway along the length of the tendon (mean tendon length = 17 cm; range = 13-21 cm); the cross-sectional area of the vessels per histologic section decreased from 336.37-137.05 microm(2). This study demonstrates that the PA insertion is well vascularized and richly innervated and that these morphological features continue along the length of the tendons.

Arthroscopic autologous chondrocyte transplantation: technical note.

We describe an arthroscopic surgical technique for tissue engineered cartilage grafting. A three-dimensional hyaluronic acid support is used for autologous chondrocyte culturing. The technique reduces morbidity of classic autologous implant and avoids open surgery and the use of a periosteal flap. The procedure includes the advantages of arthroscopic osteochondral grafting without donor site morbidity. With this technique is possible to reduce the patient morbidity, time and cost of surgery.

Micromotion between the half bearings in the interax prosthesis: a roentgen stereophotogrammetric analysis.

We assessed the migration and movement between the half-bearings of the Interax prosthesis in 18 patients using roentgen stereophotogrammetric analysis (RSA). This study showed movements of the tibial component even in successful knee arthroplasty: 17 prostheses migrated only initially and remained stable after 1 year, whereas 1 prosthesis migrated consistently throughout 3-year follow-up. RSA revealed no or minimal displacement between the half-bearings until the 4-year follow-up, confirming that their fixation to the baseplate was adequate. In the case of loosening, a rotation about the longitudinal axis of 1.3 degrees and a medial-lateral translation of 0.5 mm was observed between the half-bearings. Cold flow was revealed by RSA in the posterior region of the medial half-bearing.

Results of the original Putti-Platt procedure for shoulder instability: review of Putti's scholar experience.

Twenty patients who underwent Putti-Platt shoulder capsulorraphy were retrospectively evaluated at long-term follow-up (24-34 years). The aim of this study was to analyse the efficacy and possible degenerative changes associated with this procedure. Patients' charts were reviewed to analyse the pre-operative picture, surgical technique and post-operative program. All patients were re-examined using ASES, Rowe and Lysholm scales. Range of movement (ROM) of the shoulder operated on was compared with the non-operated one. A-P, axillary and outlet views were taken for radiographic control. Samilson criteria were followed to determine the degree of arthrosis. Clinical outcome was satisfactory in 85% of the cases with only three cases with fair results (15%). No recurrence was present in this series. The mean limitation of external rotation in abduction was 9 degrees with respect to the contra-lateral shoulder. Severe degenerative changes were observed in two cases. In conclusion, after a long follow-up period, the Putti-Platt technique has shown highly satisfactory results, with an incidence of loss of motion and joint degeneration changes similar to other procedures.

The mobility of the proximal tibio-fibular joint. A Roentgen Stereophotogrammetric Analysis on six cadaver specimens.

In six cadaver specimens the mobility of the proximal fibula in relation to the tibia was investigated during plantar/dorsiflexion of the ankle, using Roentgen Stereophotogrammetric Analysis (RSA). The role of the ankle joint, and of the calcaneofibular and talofibular ligaments was also evaluated. The greatest movements were observed along the mediolateral and anterior-posterior axes, resulting in an anterolateral displacement of the fibula head during dorsiflexion and in a postero-medial displacement during plantarflexion. This study demonstrated a limited mobility of the proximal tibiofibular joint. Moreover, the ligament cutting and the presence of constraints in the ankle region did not show any effect on the fibular movement.

Use of autologous grafts for reconstruction of osteochondral defects of the knee.

This study reports on 13 patients (mean age: 31 years) with a femoral condyle defect >1.5 cm2 who underwent treatment with an osteochondral graft of the same size obtained from the superior aspect of the lateral condyle, preserving the patellar groove. Mean follow-up was 61.5 months (range: 13-141 months). Twelve results were rated clinically as satisfactory with patients able to resume their normal pre-injury level of activity, and 1 case was rated as poor. No patient reported any patellar problems. Radiographic and computed tomographic evaluation demonstrated good integration of the graft in the host bone. The results of this technique at relatively long-term follow-up are encouraging, with a high percentage of subjective satisfaction. This technique appears to be reliable and provides a valid solution for treatment of wide cartilage defects when other techniques are too complex or inadequate.

Variation of the spatial position computed by Roentgen Stereophotogrammetric Analysis (RSA) under non-standard conditions.

Roentgen Stereophotogrammetric Analysis (RSA) has been applied to different kinds of research in order to obtain important information in the biomechanics field. Operative requirements change according to the type of investigation and sometimes practical conditions do not always permit one to respect standard specifications. The aim of this paper is to verify the reliability of the system under non-standard conditions, studying the effects of the focus-to-film distance on the determination of 3D co-ordinates of markers. The application of statistical analysis, consisting of two and three way ANalysis Of VAriance (ANOVA), showed that focus-to-film distance is not a significant source of variation, i.e., the system can correctly compute the marker position inside the calibrated space under all conditions of magnification. Since we obtained a fluctuation due to focal distance change of 10(-5) mm (LSD for 95% confidence level), we can assert that this source causes a variation strictly within the limits required by clinical investigations. Thus, this study contributes to improving the flexibility of RSA in clinical applications, making the technical requirements of the radiographic set-up less constraining.

Total knee arthroplasty without patellar resurfacing in active and overweight patients.

Overweight patients are often considered poor candidates for total knee arthroplasty (TKA). A retrospective study of this was done on 47 osteoarthritic knees treated by TKA without patella resurfacing between March 1991 and June 1993. The Hospital for Special Surgery (HSS) rating system was used for clinical evaluation, and radiographs to study the degree of osteoarthritis and radiolucency. Correlations between overweight, range of motion (ROM) and stage of patellar damage and other measured variables (HSS score, patellar pain and radiolucency) were studied. Overweight was not correlated with HSS score, radiolucency or patellar pain. ROM was significantly correlated with patellar pain and HSS score, with better results in patients with ROM between 90 degrees and 110 degrees. Therefore, we believe that TKA in osteoarthritic knees can lead to successful results, even in active or overweight patients.

Arthroscopic management of recurrent anterior dislocation of the shoulder: analysis of technical modifications on the Caspari procedure.

Arthroscopic treatment was performed on 71 patients with recurrent shoulder dislocations; all of the patients had monoplanar anterior instability attributable to arthroscopically diagnosed Bankart lesion. Of the 71 operations, 29 were performed using the original Caspari technique (follow-up, 59 months), and 42 were performed after modifications made in the original technique (follow-up, 38 months), notably improved preparation of the capsular reinsertion zone and increase in the number of monofilament points and their anchorage directly to the bone, on the spine of the scapula. We compared the results obtained in these two differently treated groups, taking into account several factors in the patient's history and clinical condition. These included the number of dislocation episodes before the operation, as well as clinical findings regarding stability, movement, function and pain (Rowe scale score), contralateral shoulder laxity, level of preoperative versus postoperative athletic activity, and postoperative recurrence rate. In the Caspari-treated group, we obtained 66% satisfactory results compared with the 90% obtained in the second group. The recurrence rate was 27% in the first group compared with 4.8% in the second group. These data were statistically significant. No correlation was found between preoperative number of dislocations and recurrence rate, nor for contralateral shoulder laxity. No significant difference was found regarding resumption of sport activity in the two groups. Our data indicate that, with accuracy in patient selection and effective surgical technique, the recurrence rate can be reduced, and results similar to those of the arthrotomic technique may be obtained.