Menisci are crucial structures for knee homeostasis: they provide increase of congruence between the articular surfaces of the distal femur and tibial plateau, bear loading, shock absorption, lubrication, and proprioception. After a meniscal lesion, the golden rule, now, is to save as much meniscus as possible: only the meniscus tissue which is identified as unrepairable should be excised and meniscal sutures find more and more indications. Several different methods have been proposed to improve meniscal healing. They include very basic techniques, such as needling, abrasion, trephination and gluing, or more complex methods, such as synovial flaps, meniscal wrapping, or the application of fibrin clots. Basic research of meniscal substitutes has also become very active in the last decades. The features needed for a meniscal scaffold are: promotion of cell migration, it should be biomimetic and biocompatible, it should resist forces applied and transmitted by the knee, it should slowly biodegrade and should be easy to handle and implant. Several materials have been tested, that can be divided into synthetic and biological. The first have the advantage to be manufactured with the desired shapes and sizes and with precise porosity dimension and biomechanical characteristics. To date, the most common polymers are polylactic acid (PGA); poly-(L)-lactic acid (PLLA); poly- (lactic-co-glycolic acid) (PLGA); polyurethane (PU); polyester carbon and polycaprolactone (PCL). The possible complications, more common in synthetic than natural polymers are poor cell adhesion and the possibility of developing a foreign body reaction or aseptic inflammation, leading to alter the joint architecture and consequently to worsen the functional outcomes. The biological materials that have been used over time are the periosteal tissue, the perichondrium, the small intestine submucosa (SIS), acellular porcine meniscal tissue, bacterial cellulose. Although these have a very high biocompatibility, some components are not suitable for tissue engineering as their conformation and mechanical properties cannot be modified. Collagen or proteoglycans are excellent candidates for meniscal engineering, as they maintain a high biocompatibility, they allow for the modification of the porosity texture and size and the adaptation to the patient meniscus shape. On the other hand, they have poor biomechanical characteristics and a more rapid degradation rate, compared to others, which could interfere with the complete replacement by the host tissue. An interesting alternative is represented by hydrogel scaffolds. Their semi-liquid nature allows for the generation of scaffolds with very precise geometries obtained from diagnostic images (i.e. MRI).

Promising results have been reported with alginate and polyvinyl alcohol (PVA). Furthermore, hydrogel scaffolds can be enriched with growth factors, platelet-rich plasma (PRP) and Bone Marrow Aspirate Concentrate (BMAC). In recent years, several researchers have developed meniscal scaffolds combining different biomaterials, to optimize the mechanical and biological characteristics of each polymer. For example, biological polymers such as chitosan, collagen and gelatin allow for excellent cellular interactions, on the contrary synthetic polymers guarantee better biomechanical properties and greater reliability in the degradation time. Three-dimensional (3D) printing is a very interesting method for meniscus repair because it allows for a patient-specific customization of the scaffolds. The optimal scaffold should be characterized by many biophysical and biochemical properties as well as bioactivity to ensure an ECM-like microenvironment for cell survival and differentiation and restoration of the anatomical and mechanical properties of the native meniscus. The new technological advances in recent years, such as 3D bioprinting and mesenchymal stem cells management will probably lead to an acceleration in the design, development, and validation of new and effective meniscal substitutes.

Summary:

Hamstring tendons (HT) represent a widely used autograft for ACL reconstruction. Harvesting, processing and pretensioning procedures together with the time out of the joint could theoretically hamper tendon cells (TCs) viability. The authors hypothesize that HT cells are not impaired at the end of the surgical procedures and their tenogenic phenotype may be strongly improved by exposure to PEMF.

Introduction and Objective

Kinematic Alignment (KA) is a surgical technique that restores the native knee alignment following Total Knee Arthroplasty (TKA). The association of this technique with a medial pivot implant design (MP) attempts to reestablish the physiological kinematics of the knee. Aim of this study is to analyze the clinical and radiological outcomes of patients undergoing MP-TKA with kinematic alignment, and to assess the effect of the limb alignment and the orientation of the tibial component on the clinical outcomes.

PURPOSE OF THE STUDY: We reported of eleven cases of early spontaneous osteonecrosis (SO) of the knee successfully treated with an extracorporeal shock-wave treatment (ESWT).

Traumatic and vascular theories have been proposed as the cause of the SO, lack of blood in some critical areas, such as subchondral bone of femoral condyles or tibial plateaus, has been considered the underlying condition of this pathology.

ESWT can be suggested as an effective conservative treatment for SO of the knee.

MATERIALS AND METHODS: Ten patients with medial femoral condyle osteonecrosis of the knee (one bilateral) were evaluated. Exclusion criteria was evidence of a structural collapse of subchondral bone. Two patients had received a femoro-popliteal by-pass within the last year, while others five presented a deficit of the vascular axis of the homolateral lower limb documented by an eco-colordoppler. A clinical evaluation was taken at the diagnosis using KSS, PPI, NRS and VAS. Plain radiographs and MRI confirmed the diagnosis of osteonecrosis.

Patients were treated with a cycle of three ESWT performed with 2000 pulses of 0,28 mJ/mm2 with Wolf Piezoson 300 with 6,5 MHz ultrasounds for three times in a month.

Clinical evaluation was performed at first and at third month after treatment and a MRI evaluation was performed at fourth month after treatment.

RESULTS: Clinical evaluation showed a significant improvement of symptoms and articular functionality. MRI of all cases revealed the continuity of the cartilage with a reduction in bone marrow edema and no collapse of lesion.

DISCUSSION: In our study, a single cycle of ESWT produced an improvement of the clinical and MRI aspects in eleven cases of SO of the knee. The neo-angiogenetic effect of the ESWT appears to accelerate the time for the symptom remission.

ESWT might have the potential to avoid the need for surgical treatment.

Introduction: The purpose of this work is to create an in vitro model of engineered osteochondral composite by combining a cylinder of calcium phosphate and cartilage tissue produced by isolated swine articular chondrocytes seeded onto fibrin glue.

Methods: Swine articular chondrocytes were enzimatically isolated and seeded onto fibrin glue. Immediately before gel polymerization, the fibrin glue was placed in contact with the cylinders of calcium phosphate. The osteochondral composites were left in standard culture conditions for 1,3,6 weeks. At the end of experimental times the samples were macroscopically analysed and processed for histological evaluation.

Results: Preliminary data showed a macroscopically integrity of the osteochondral samples. Histology showed cartilage like tissue maturing within the fibrin glue scaffold.

Discussion: The results demonstrate that isolated chondrocytes, seeded onto fibrin glue, produce a cartilage-like matrix that integrates with a cylinder of calcium phosphate.

This tissue engineered osteochondral composite could represent a valuable model for further in vivo studies on the repair of osteochondral lesions.

Background: The aim of this study is to evaluate the efficacy of extracorpereal shock wave therapy (ESWT) in some of most frequent muscularskeletal pathologies.

Material and methods: From July to October 2004 310 patients were treated with ESWT, suffering from the following pathologies: 96 symptomatic calcific tendonitis of the shoulder, 53 symptomatic sub-acromial impingement, 48 humeral epichondylitis, 52 plantar fasciitis, 24 pertrochanteric bursitis, 15 Achilleous tendinopathy and 22 patellar tendinopathy.

Patients were evaluated clinically and instrumentally before the first application and at one and three months of follow-up. Three disability scales we utilized (NRS, Mcgill Pain Questionnaire e Chronic Pain Grade Questionnaire).

Results: We observed a reduction of the pain and an increase of the articular functionality in 83% of calcific tendonitis of the shoulder, in 55% of sub-acromial impingement, in 76% of epichondylitis, in 74% of palantar fasciitis, in 90% of pertrochanteric bursitis, in 82% of Achilleous tendinopathy and in 86% of patellar tendinopaty.

Discussion: The data confirm the therapy with ESWT is efficient in some of most frequent musculoskeletal pathologies, with variable outcome in the various pathologies under investigation.

The purpose of this work was to create an in vitro model of tissue-engineered cartilage structure produced by isolated swine articular chondrocytes, expanded in culture and seeded onto a biological scaffold.

Swine articular chondrocytes were enzymatically isolated from pig joints and expanded in monolayer culture. When confluence was reached, cells were resuspended and seeded in vitro onto biological collagen scaffolds for 3, 4 and 6 weeks. Samples were retrieved from the culture and analysed macroscopically and biomechanically by compressive test. Gross evaluation was performed by simple probing, sizing and weighing the samples at all time periods. A baseline of the values was also recorded at time 0. Then, samples were biomechanically tested by unconfined compression and shear tests. Finally, the samples were fixed in 4% paraformaldehyde and processed for histological evaluation. Some samples were stained with Safranin-o, and some others subjected to immunostaining analysis for type II collagen.

Upon retrieval, samples showed dimensional enlargement and mass increase over time and gross mechanic integrity by simple probing. A biomechanical test demonstrated an initial reduction in the values of compressive and shear parameters, followed by a consistent increase throughout the tested time points. Histology showed cartilage-like tissue maturing over time within the biological scaffold.

The results from this study demonstrate that isolated chondrocytes could be seeded onto a biological collagen scaffold, producing cartilage-like matrix with tissue-specific morphology and biomechanical integrity. This tissue-engineered cartilage structure is easily reproducible and it could represent a valuable model for studying the behaviour of different variables on the newly formed cartilage.