We aim to analyze the role of patient-related factors on the yield of progenitor cells in the bone marrow aspiration concentrate (BMAC). We performed a retrospective analysis of patients who underwent autologous iliac crest-based BMAC therapy between Jan 2021–and June 2021. Patient-related factors such as age, sex, and comorbidities and procedure variables such as aspirate volume were analyzed. The yield of the bone marrow aspiration concentrate was assessed with MNC count and CFU assay from the aspirates. 63 patients with a mean age of 51.33±17.98 years were included in the study. There were 31 males and 32 females in the study population with a mean volume of 67.16±17.312 ml being aspirated from the iliac crest for the preparation of BMAC. The final aspirate had a mean MNC count of 20.16±15.73×10^6 cells which yielded a mean of 11±12 CFUs. We noted significant negative correlation between age and MNC count (r=minus;0.671, p<0.001) and CFUs (r=minus;0.688, p<0.001). We did not find the sex to have any significant role in MNC (p=0.082) count or CFUs formed (p=0.348). The presence of comorbidity significantly reduced the MNC count (p=0.003) and CFUs formed (p=0.005). The aspiration volume significantly negatively correlated with MNC count (r=minus;0.731, p<0.001) and CFUs (r=minus;0.618, p<0.001). The MNC count and CFUs formed from the BMAC depend on the patient-specific subjective variables such as age, and comorbid conditions present in them. Sex and volume of aspiration do not alter the MNC count or the CFUs formed from BMAC

The optimal treatment strategy for post-traumatic long bone non-unions is subject of an ongoing discussion. At the Maastricht University Medical Center (MUMC+) the induced membrane technique is used to treat post-traumatic long bone non-unions. This technique uses a multimodal treatment algorithm involving bone marrow aspirate concentrate (BMAC), the reamer-irrigator-aspirator (RIA) and P-15 bioactive peptide (iFactor, Cerapedics). Bioactive glass (S53P4 BAG, Bonalive) is added when infection is suspected. This study aims to objectify the effect of this treatment algorithm on the health-related quality of life (HRQoL) of patients with post-traumatic long bone non-unions. We hypothesized that HRQoL would improve after treatment. From January 2020 to March 2023, consecutive patients who were referred to a multidisciplinary (trauma, orthopaedic and plastic surgery) non-union clinic at the MUMC+, The Netherlands, were evaluated using the Non-Union Scoring System (NUSS). The EQ-5D-5L questionnaire and the Lower Extremity Functional Scale (LEFS) were employed to obtain HRQoL outcomes both prior to and subsequent to surgery, with a follow-up at 6, 18 and 35 weeks. Seventy-six patients were assessed at baseline (T0), with a mean NUSS of 40 (± 13 SD). Thirty-eight patients had their first follow-up, six weeks after surgery (T1). Thirty-one patients had a second follow-up at 18 weeks (T2), and twenty patients had the third follow-up at 35 weeks (T3). The EQ-5D index mean at baseline was 0.480, followed by an index of 0.618 at T1, 0.636 at T2, and 0.702 at T3. A significant difference was found in the HRQoL score between T0 and T1, as well as T2 and T3 (p<0.001; p=0.011). The mean LEFS significantly increased from 26 before intervention to 34, 39, and 43 after treatment (p<0.001; p=0.033; p=0.016). This study demonstrated a significant improvement in the health-related quality of life of patients with post-traumatic long bone non-unions after the standardized treatment algorithm following the induced membrane technique

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

Abstract. Objectives. Bone marrow aspirate concentrate (BMAC), together with fibrin glue (Tisseel, Baxter, UK) and Hyaluronic acid (HA) were used as a one-step cell therapy treating patients with ankle cartilage defects in our hospital. This therapy was proven to be safe, with patients demonstrating a significant improvement 12 months post-treatment. Enriched mesenchymal stem cells (MSCs) in BMAC are suggested inducers of cartilage regeneration, however, currently there is no point-of-care assessment for BMAC quality; especially regarding the proportion of MSCs within. This study aims to characterise the cellular component of CCR-generated BMAC using a point-of-care device, and to investigate if the total nucleated cell (TNC) count and patient age are predictive of MSC concentration. Methods. During surgery, 35ml of bone marrow aspirate (BMA) was collected from each patients’ iliac crest under anaesthesia, and BMAC was obtained via a commercial kit (Cartilage Regeneration kit, CCR, Innotec. ®. , UK). BMAC was then mixed with thrombin (B+T) for injection with HA and fibrinogen. In our study, donor-matched BMA, BMAC and B+T were obtained from consented patients (n=12, age 41 ± 16years) undergoing surgery with BMAC therapy. TNC, red blood cell (RBC) and platelet (PLT) counts were measured via a haematology analyser (ABX Micros ES 60, Horiba, UK), and the proportion of MSCs in BMA, BMAC and B+T were assessed via colony forming unit-fibroblast (CFU-F) assays. Significant differences data in matched donors were tested using Friedman test. All data were shown as mean ± SD. Results. Mean TNC counts in BMA and BMAC were not significantly different (14.0 ± 4.4 million/ml and 19.4 ± 32.9 million/ml, respectively, P>0.9999). However, TNC counts were significantly lower in B+T compared to BMAC (9.7 ± 24.5 million/ml and 19.4 ± 32.9 million/ml, respectively, P=0.0167). Similarly, PLT counts were decreased in B+T compared to BMAC (40.7 ± 30.7 million/ml and 417.5 ± 365.5 million/ml, respectively, P<0.0001), however, PLTs were significantly concentrated in BMAC compared to BMA (417.5 ± 365.5 million/ml and 114.8 ± 61.6 million/ml, respectively, P=0.0429). RBC counts were significantly decreased in BMAC and B+T compared to BMA (P=0.0322 and P<0.0001, respectively). Higher concentration of MSCs were observed in BMAC compared to BMA (0.006% ± 0.01% and 0.00007% ± 0.0001%, respectively, P=0.0176). Similar to TNCs and PLTs, the proportion of MSCs significantly decreased in B+T compared to BMAC (0.0004% ± 0.001% and 0.006% ± 0.01%, respectively, P=0.0023). Furthermore, patient age and TNC counts did not correlate with MSC concentration (Spearman's Rank test, P=0.3266 and P=0.4880, respectively). Conclusions. BMAC successfully concentrated PLTs, but BMAC preparations were highly variable. Mixing BMAC and thrombin however, as described in the CCR protocol, resulted in a dramatic reduction in TNCs, PLTs and MSCs. TNC counts and patient age could not be used to predict the MSC proportion in the BMAC based on current data. Future work aims to look at the biomolecule profile of BMAC plasma, and to correlate them to patient clinical outcomes. Declaration of Interest. (a) fully declare any financial or other potential conflict of interest