Microfracture surgery combined with platelet-rich plasma injection in treating osteochondral lesions of talus: A system review and update meta analysis.

BACKGROUND: To systematically evaluate the efficacy of arthroscopic microfracture surgery combined with platelet-rich plasma (PRP) injection in treating osteochondral lesions of talus (OLT). METHOD: A computer-based search of the PubMed, EMbase, Cochrane Library was developed. The search time was dated in December 2022. Randomized controlled trials and prospective case control studies comparing the treatment of OLT with microfracture surgery combined with PRP injection and microfracture surgery alone were included. The quality of the literatures were evaluated. Meta analysis was completed using the data of postoperative pain and function scores of the ankle joint reported in the literature. RESULTS: Five randomized controlled trials with a total of 198 patients were included. Compared with microfracture surgery alone, meta-analysis showed that the postoperative visual analogue scale (VAS) score for ankle pain was significantly lower (P < 0.001), and the American Orthopaedic Foot and Ankle Society score (AOFAS) was significantly better ( P < 0.001) in the group of microfracture surgery combined with PRP injection. The change of VAS and AOFAS was also significantly better in the group of microfracture surgery combined with PRP injection (P < 0.001). CONCLUSION: Arthroscopic microfracture surgery combined with PRP injection in treating OLT can significantly reduce pain and improve ankle function. More long-term follow-up, high-quality studies are needed. LEVEL OF EVIDENCE: II.

Biomechanics of calcaneus impacted by talus: a dynamic finite element analysis.

This paper aimed to investigate the biomechanical changes during the talus impact with the calcaneus at varying velocities. Various three-dimensional reconstruction software was utilized to construct a finite element model that consisted of the talus, calcaneus, and ligaments. The explicit dynamics method was used to explore the process of the talus impacting on the calcaneus. The velocity of impact was altered from 5 m/s to 10 m/s with a 1 m/s interval. Stress readings were collected from the posterior, intermediate, and anterior subtalar articular (PSA, ISA, ASA), calcaneocubic articular (CA), Gissane Angle (GA), calcaneal base (BC), medial wall (MW), and lateral wall (LW) of the calcaneus. The changes in the amount and distribution of stress in the different regions of the calcaneus that varied with velocity were analysed. The model was validated through comparison with findings from the existing literature. During the process of impact between the talus and calcaneus, the stress in the PSA reached its peak first. Notably, stress was concentrated mainly in the PSA, ASA, MW, and LW of the calcaneus. At varying impact velocities of the talus, the mean maximum stress of the PSA, LW, CA, BA, and MW exhibited statistically significant differences (P values were 0.024, 0.004, <0.001, <0.001, and 0.001, respectively). However, the mean maximum stress of the ISA, ASA, and GA was not statistically significant (P values were 0.289, 0.213, and 0.087, respectively). In comparison with the velocity at 5 m/s, the mean maximum stress increases in each region of the calcaneus at a velocity of 10 m/s were as follows: PSA 73.81%, ISA 7.11%, ASA 63.57%, GA 89.10%, LW 140.16%, CA 140.58%, BC 137.67%, MW 135.99%. The regions of stress concentration were altered, and the magnitude and sequence of peak stress in the calcaneus also varied according to the velocity of the talus during impact. In conclusion, the velocity of the talus during impact had a significant influence on the magnitude and distribution of stress within the calcaneus, which was a crucial factor in the development of calcaneal fractures. It was possible that the magnitude and sequence of stress peaks played a vital role in determining the emergence of fracture patterns.

Benchmark dose for cadmium exposure and elevated N-acetyl-ß-D-glucosaminidase: a meta-analysis.

Cadmium (Cd) is a well-known nephrotoxic contaminant, and N-acetyl-ß-D-glucosaminidase (NAG) is considered to be an early and sensitive marker of tubular dysfunction. The link between Cd exposure and NAG level enables us to derive the benchmark dose (BMD) of Cd. Although several reports have already documented urinary Cd (UCd)-NAG relationships and BMD estimations, high heterogeneities arise due to the sub-populations (age, gender, and ethnicity) and BMD methodologies being employed. To clarify the influences that these variables exert, firstly, a random effect meta-analysis was performed in this study to correlate the UCd and NAG based on 92 datasets collected from 30 publications. Later, this established correlation (Ln(NAG) = 0.51 × Ln(UCd) + 0.83) was applied to derive the UCd BMD5 of 1.76 µg/g creatinine and 95 % lower confidence limit of BMD5 (BMDL5) of 1.67 µg/g creatinine. While the regressions for different age groups and genders differed slightly, it is age and not gender that significantly affects BMD estimations. Ethnic differences may require further investigation given that limited data is currently available. Based on a comprehensive and systematic literature review, this study is a new attempt to quantify the UCd-NAG link and estimate BMD.

[Changes in peripheral blood T lymphocyte subsets of rabbits in early stage after transplantation of tissue engineered bone constituted by biologically-derived scaffold].

OBJECTIVE: To observe the changes in the peripheral blood T lymphocyte subsets and the histomorphology of the transplanted tissues in the rabbits in the early stage after transplantation of the tissue engineered bone constituted by the biologically-derived scaffold and to confirm the feasibility of the biologically-derived materials as a scaffold in the bone tissue engineering. METHODS: Forty-eight healthy New Zealand rabbits (weight, 2. 0-2.5 kg) with a 1-cm defect were equally and randomly divided into 4 groups: Groups A-D. The partial demineralized freeze-dried bone (PDFDB), the tissue engineered bone constructed by the osteoblasts derived from the lactant rabbit periosteum as a seeding cell, the xenogeneic cancellous bone undergoing the antigen self-digestion, partial demineralization and freeze-dried process as a scaffold, and the fresh xenogeneic allografting bone were respectively transplanted into the segmental defects of the rabbit radii in Groups A-D. To examine the effects of the 4 different materials, the flow cytometry was used to observe the changes in the T lymphocyte subsets in the rabbit peripheral blood at 1, 2, and 4 weeks after the operations and to examine the osteogenesis achieved by the 4 materials, the histological observations were also performed at 2, 4, 8, and 12 weeks after the operations. RESULTS: Two weeks after the tissue engineered bone transplantation in Group B, the osteoblasts and chondroblasts were found in the apertures of the scaffold, the new bone formation could be observed, the osteoclasts could be seen in the peripheral zone, and some of the netlike frameworks were destroyed and absorbed. Four weeks after the operation, the histological observation revealed that the osteocartilagionous callus turned into a woven bone. The peripheral blood T lymphocyte subsets of CD4+ and CD8+ were significantly greater in number 1-2 weeks after the operations and in Groups A and B than before the operations and in the other groups (P<0. 05);4 weeks after the operations the T lymphocyte subset of CD4+ was only slightly greater in number than before the operations, but with no statistically significant difference (P>0.05). In Group C, the increase of the T lymphocyte subsets of CD4+ and CD8+ was not significant after the operation (P>0.05). The T lymphocyte subsets of CD4+ and CD8+ were significantly greater in number 1, 2 and 4 weeks after the operations and in Group D than before the operation and in the other groups (P<0.05). CONCLUSION: The tissue engineered bone constructed by the partial demineralized freeze-dried bone as a scaffold does not cause a serious immunologic rejection in the early stage after the transplantation and does not affect its good ability to repair the bone defect. The biologically-derived bone can be used as a scaffold in the bone tissue engineering.

[Experimental study of periosteal osteoblasts coculture with freeze-dried demineralized bone matrix].

OBJECTIVE: To investigate the feasibility of freeze-dried demineralized bone matrix (FDBM) as scaffold material in bone tissue engineering. METHODS: Osteoblasts which were isolated from cranial periosteum of New Zealand rabbits were cultured as the seeding cells, then the cells were cocultured with heterogenous FDBM in vitro. The cell-material complex was observed under phase microscope, light microscope and electronic scanning microscope in order to evaluate the interaction between cells and FDBM. RESULTS: Eight hours after coculture, the osteoblasts adhered to FDBM scaffolds. Seven days later, the osteoblasts differentiated and proliferated in FDBM network. Extracellular matrix was secreted and calcium nodes were formed among osteoblasts. CONCLUSION: FDBM is a good scaffold material for the bone tissue engineering.