Mechanical stimulation-induced purinome priming fosters osteogenic differentiation and osteointegration of mesenchymal stem cells from the bone marrow of post-menopausal women.

BACKGROUND: Mechanical stimulation (MS) significantly increases the release of adenine and uracil nucleotides from bone marrow-derived mesenchymal stem cells (BM-MSCs) undergoing osteogenic differentiation. Released nucleotides acting via ionotropic P2X7 and metabotropic P2Y6 purinoceptors sensitive to ATP and UDP, respectively, control the osteogenic commitment of BM-MSCs and, thus, bone growth and remodelling. Yet, this mechanism is impaired in post-menopausal (Pm)-derived BM-MSCs, mostly because NTPDase3 overexpression decreases the extracellular accumulation of nucleotides below the levels required to activate plasma membrane-bound P2 purinoceptors. This prompted us to investigate whether in vitro MS of BM-MSCs from Pm women could rehabilitate their osteogenic commitment and whether xenotransplantation of MS purinome-primed Pm cells promote repair of critical bone defects in an in vivo animal model. METHODS: BM-MSCs were harvested from the neck of femora of Pm women (70 ± 3 years old) undergoing total hip replacement. The cells grew, for 35 days, in an osteogenic-inducing medium either submitted (SS) or not (CTR) to MS (90 r.p.m. for 30 min) twice a week. Increases in alkaline phosphatase activity and in the amount of osteogenic transcription factors, osterix and osteopontin, denoted osteogenic cells differentiation, while bone nodules formation was ascertain by the alizarin red-staining assay. The luciferin-luciferase bioluminescence assay was used to quantify extracellular ATP. The kinetics of the extracellular ATP (100 µM) and UDP (100 µM) catabolism was assessed by HPLC. The density of P2Y6 and P2X7 purinoceptors in the cells was assessed by immunofluorescence confocal microscopy. MS-stimulated BM-MSCs from Pm women were xenotransplanted into critical bone defects drilled in the great trochanter of femora of one-year female Wistar rats; bone repair was assessed by histological analysis 10 days after xenotransplantation. RESULTS: MS-stimulated Pm BM-MSCs in culture (i) release 1.6-fold higher ATP amounts, (ii) overexpress P2X7 and P2Y6 purinoceptors, (iii) exhibit higher alkaline phosphatase activity and overexpress the osteogenic transcription factors, osterix and osteopontin, and (iv) form larger bone nodules, than CTR cells. Selective blockage of P2X7 and P2Y6 purinoceptors with A438079 (3 µM) and MRS 2578 (0.1 µM), respectively, prevented the osteogenic commitment of cultured Pm BM-MSCs. Xenotransplanted MS purinome-primed Pm BM-MSCs accelerated the repair of critical bone defects in the in vivo rat model. CONCLUSIONS: Data suggest that in vitro MS restores the purinergic cell-to-cell communication fostering the osteogenic differentiation and osteointegration of BM-MSCs from Pm women, a strategy that may be used in bone regeneration and repair tactics.

Scott-Taor Syndrome: A Clinical Case Report.

Scott-Taor syndrome is a benign bone dysplasia with less than 50 cases reported. The latter is an autosomal dominant disease characterized mainly by patellar a/hypoplasia and bilateral malunion ossification of the ischiopubic junction, a wide gap between the first and second toes. The diagnosis is clinical and radiographical. Here, we present a 17-year-old female patient with this rare syndrome. Considering this diagnosis is crucial for a better understanding of the pathology and to effectively contextualize the patient's clinical findings.

Effective VTE prophylaxis with enoxaparin after elective THR or TKR: a retrospective observational study.

Background: Orthopedic patients are at the highest risk for venous thromboembolism (VTE). Nowadays, with VTE prophylaxis as a routine in patients undergoing total hip replacement (THR) and total knee replacement (TKR), fatal pulmonary embolism (PE) is rare and the rates of symptomatic VTE within 3 months dropped to 1.3%-10%, compared with the rates of 50%-70% before VTE prophylaxis implementation. In this study, we aim to evaluate the VTE prophylaxis and incidence in patients who underwent THR and TKR in Centro Hospitalar Universitário de Santo António (CHUdSA). Methods: We included 483 patients who underwent elective THR or TKR in CHUdSA from March 2019 to February 2020 and who were under enoxaparin as a VTE prophylaxis drug. All data related to prescribed enoxaparin were collected from the nationwide common electronic drug prescription system (PEM). Results: Of the 483 eligible patients, 192 (39.75%) underwent elective THR and 291 (60.25%) underwent TKR. Enoxaparin was prescribed for 31.86 ± 5.98 and 30.28 ± 5.97 days, on average, for the THR and TKR groups, respectively (P = .005). Patients completed, on average, 29.38 ± 8.12 days and 28.20 ± 7.32 days of VTE prophylaxis with enoxaparin in the THR and TKR groups, respectively (P = .098). The incidence of VTE was approximately 3.13% and 0.69% in the THR and TKR groups, respectively (P = .064). Conclusion: In CHUdSA, we usually prescribe enoxaparin 40 mg once daily for up to 35 days for VTE prophylaxis after THR or TKR. High therapeutic compliance rates resulted in very few events.

Total knee arthroplasty coronal alignment and tibial base stress-a new numerical evaluation.

Background: Total knee arthroplasty (TKA) is one of the most frequently performed orthopedic procedures. The correct positioning and alignment of the components significantly affects prosthesis survival. Considering the current controversy regarding the target of postoperative alignment of TKA, this study evaluated the tension at tibial component interface using two numerical methods. Methods: The stress of the prosthesis/bone interface of the proximal tibial component was evaluated using two numerical methods: the finite element method (FEM) and the new meshless method: natural neighbor radial point interpolation method (NNRPIM). The construction of the model was based on Zimmers NexGen LPS-Flex Mobile® prosthesis and simulated the forces by using a free-body diagram. Results: Tibiofemoral mechanical axis (TFMA) for which a higher number of nodes are under optimal mechanical tension is between 1° valgus 2° varus. For values outside the interval, there are regions under the tibial plate at risk of bone absorption. At the extremities of the tibial plate of the prosthesis, both medial and lateral, independent of the alignment, are under a low stress. In all nodes evaluated for all TFMA, the values of the effective stresses were higher in the NNRPIM when compared with the FEM. Conclusion: Through this study, we can corroborate that the optimal postoperative alignment is within the values that are currently considered of 0 ± 3° varus. It was verified that the meshless methods obtain smoother and more conservative results, which may make them safer when transposed to the clinical practice.

Silencing NTPDase3 activity rehabilitates the osteogenic commitment of post-menopausal stem cell bone progenitors.

BACKGROUND: Endogenously released adenine and uracil nucleotides favour the osteogenic commitment of bone marrow-derived mesenchymal stromal cells (BM-MSCs) through the activation of ATP-sensitive P2X7 and UDP-sensitive P2Y6 receptors. Yet, these nucleotides have their osteogenic potential compromised in post-menopausal (Pm) women due to overexpression of nucleotide metabolizing enzymes, namely NTPDase3. This prompted us to investigate whether NTPDase3 gene silencing or inhibition of its enzymatic activity could rehabilitate the osteogenic potential of Pm BM-MSCs. METHODS: MSCs were harvested from the bone marrow of Pm women (69 ± 2 years old) and younger female controls (22 ± 4 years old). The cells were allowed to grow for 35 days in an osteogenic-inducing medium in either the absence or the presence of NTPDase3 inhibitors (PSB 06126 and hN3-B3s antibody); pre-treatment with a lentiviral short hairpin RNA (Lenti-shRNA) was used to silence the NTPDase3 gene expression. Immunofluorescence confocal microscopy was used to monitor protein cell densities. The osteogenic commitment of BM-MSCs was assessed by increases in the alkaline phosphatase (ALP) activity. The amount of the osteogenic transcription factor Osterix and the alizarin red-stained bone nodule formation. ATP was measured with the luciferin-luciferase bioluminescence assay. The kinetics of the extracellular ATP (100 µM) and UDP (100 µM) catabolism was assessed by HPLC RESULTS: The extracellular catabolism of ATP and UDP was faster in BM-MSCs from Pm women compared to younger females. The immunoreactivity against NTPDase3 increased 5.6-fold in BM-MSCs from Pm women vs. younger females. Selective inhibition or transient NTPDase3 gene silencing increased the extracellular accumulation of adenine and uracil nucleotides in cultured Pm BM-MSCs. Downregulation of NTPDase3 expression or activity rehabilitated the osteogenic commitment of Pm BM-MSCs measured as increases in ALP activity, Osterix protein cellular content and bone nodule formation; blockage of P2X7 and P2Y6 purinoceptors prevented this effect. CONCLUSIONS: Data suggest that NTPDase3 overexpression in BM-MSCs may be a clinical surrogate of the osteogenic differentiation impairment in Pm women. Thus, besides P2X7 and P2Y6 receptors activation, targeting NTPDase3 may represent a novel therapeutic strategy to increase bone mass and reduce the osteoporotic risk of fractures in Pm women.

Knee positioning systems for X-ray environment: a literature review.

The knee is one of the most stressed joints of the human body, being susceptible to ligament injuries and degenerative diseases. Due to the rising incidence of knee pathologies, the number of knee X-rays acquired is also increasing. Such X-rays are obtained for the diagnosis of knee injuries, the evaluation of the knee before and after surgery, and the monitoring of the knee joint's stability. These types of diagnosis and monitoring of the knee usually involve radiography under physical stress. This widely used medical tool provides a more objective analysis of the measurement of the knee laxity than a physical examination does, involving knee stress tests, such as valgus, varus, and Lachman. Despite being an improvement to physical examination regarding the physician's bias, stress radiography is still performed manually in a lot of healthcare facilities. To avoid exposing the physician to radiation and to decrease the number of X-ray images rejected due to inadequate positioning of the patient or the presence of artefacts, positioning systems for stress radiography of the knee have been developed. This review analyses knee positioning systems for X-ray environment, concluding that they have improved the objectivity and reproducibility during stress radiographs, but have failed to either be radiolucent or versatile with a simple ergonomic set-up.

Effects of tailored lateral wedge insoles on medial knee osteoarthritis based on biomechanical analysis: 12-week randomized controlled trial.

BACKGROUND: Lateral wedge insoles adjusted by biomechanical analysis may improve the condition of patients with medial knee osteoarthritis. DESIGN: This is a prospective, randomized, controlled, single-blind clinical trial. SETTING: The study was conducted in a biomechanics laboratory. SUBJECTS: A total of 38 patients with medial knee osteoarthritis were allocated to either an experimental group (lateral wedge insoles) or a control group (neutral insoles). INTERVENTIONS: Experimental group (n = 20) received an adjusted lateral wedge insole of 2, 4, 6, 8, or 10 degrees, after previous biomechanical analysis. Control group (n = 18) received a neutral insole (0 degrees). All patients used the insoles for 12 weeks. MAIN MEASURES: Visual analogue scale, Knee Injury and Osteoarthritis Outcome Score questionnaire, biomechanical parameters: first and second peak of the external knee adduction moment and knee adduction angular impulse, and physical performance tests: 30-second sit-to-stand test, the 40-m fast-paced walk test, and the 12-step stair-climb test. RESULTS: After 12 weeks, between-group differences did not differ significantly for pain intensity (-12.5 mm, (95% CI -29.4-4.4)), biomechanical parameters (p = 0.05), Knee Injury and Osteoarthritis Outcome Score, and physical performance tests, except on the Knee Injury and Osteoarthritis Outcome Score subscale other symptoms (p = 0.002; 13.8 points, (95% CI 5.6-22.0)). CONCLUSION: Tailored wedge insoles were no more effective at improving biomechanical or clinically meaningful outcomes than neutral insoles, except on symptoms. More participants from the experimental group reported they felt some improvement. However, these effects were minimal and without clinical significance.

Surgical Treatment for Congenital Dislocation of the Patella in a Young Adult: A Case Report.

CASE: We present an 18-year-old man with poor alignment of the lower limbs, marked by congenital dislocation of the left patella, with gait impairment, and an associated 20° flexion contracture. Surgical treatment was performed with a single complex procedure with the release of the lateral retinaculum, capsule, and iliotibial tract, followed by a subtraction trochleoplasty, tibial tubercle transfer, elongation of the quadriceps tendon, and anatomical reconstruction of the medial patellofemoral ligament. At the 5-year follow-up, the patient had a significant improvement in gait pattern, with the patella centered on the new trochlear groove without any signs of patellar instability. CONCLUSIONS: The approach of congenital dislocation of the patella is controversial, and although numerous procedures have been described in children, the approach in adults should be individually tailored. In this case, trochlear deepening and preserving the trochlear cartilage proved to be an effective option for treating a congenital dislocation.