Background: To investigate the efficacy and safety of autologous micro-fragmented adipose tissue (MF-AT) for improving joint function and cartilage repair in patients with knee osteoarthritis. Methods: From March 2019 to December 2020, 20 subjects (40 knees) between 50 and 65 years old suffering from knee osteoarthritis were enrolled in the study and administered a single injection of autologous MF-A. The data of all patients were prospectively collected. The Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), knee society score (KSS), hospital for special surgery (HSS) score, visual analogue score (VAS) pain score, changes in cartilage Recht grade on magnetic resonance imaging (MRI) and adverse events were analyzed before and 3, 6, 9, 12 and 18 months after injection. Results: The WOMAC, VAS, KSS and HSS scores at 3, 6, 9, 12 and 18 months after injection were improved compared with those before injection (p < 0.05). There was no significant difference in WOMAC scores between 9 and 12 months after injection (p > 0.05), but the WOMAC score 18 months after injection was worse than that at the last follow-up (p < 0.05). The VAS, KSS and HSS scores 9, 12 and 18 months after injection were worse than those at the last follow-up (p < 0.05). The Recht score improvement rate was 25%. No adverse events occurred during the follow-up. Conclusions: Autologous MF-AT improves knee function and relieves pain with no adverse events. However, the improved knee function was not sustained, with the best results occurring 9–12 months after injection and the cartilage regeneration remaining to be investigated.

Objective Both unilateral biportal endoscopic discectomy (UBED) and percutaneous endoscopic interlaminar discectomy (PEID) could achieve favorable outcomes for lumbar disc herniation (LDH). There are limited studies comparing the two different methods of endoscopic discectomy. The objective was to comprehensively compare the clinical outcome and muscle invasiveness of UBED and PEID for the treatment of LDH at L5/S1 level with at least 1‐year follow‐up. Methods The retrospective cohort study enrolled 106 LDH patients of L5/S1 level from January 2018 to December 2020. There were 51 patients who underwent UBED (22 males and 29 females, 43.8 ± 14.2 years old) and 55 patients underwent PEID (28 males and 27 females, 42.3 ± 13.8 years old). Clinical outcomes and surgical invasiveness were compared between the two groups for at least 1 year follow‐up. Clinical outcomes included visual analogue scale (VAS) scores, Oswestry Disability Index (ODI), complications, recurrence of LDH, intraoperative anesthesia time, operative time, number of intraoperative fluoroscopies, and postoperative length of stay. Surgical invasiveness was evaluated with serum CPK level and change rate of lean multifidus cross‐sectional area (LMCSA). Independent‐sample t test and paired sample t test were used to compare continuous data. Chi‐square test and Fisher's precision probability tests were used to analyze the categorical data. Results Both groups achieved favorable clinical outcomes at the last follow‐up, including VAS and ODI (all Ps <0.05). The intraoperative anesthesia time for UBED was longer, but with no difference of operative time. As for intraoperative fluoroscopy times (2.5 vs 2.4), postoperative length of stay (2.1 vs 2.0 days), postoperative complications (5.9% vs 3.6%), there were also no significant difference. The serum CPK level and change rate of LMCSA for UBED was higher than PEID at postoperative 1st day. At the last follow‐up, there was no significant difference in the change rate of LMCSA between the two groups (P = 0.096). Conclusions Both UBED and PEID could achieve favorable clinical outcomes for the treatment of L5/S1 LDH. Despite UBED is more invasive, the radiological manifestation of paraspinal muscle invasiveness was equal at last follow‐up with at least 1 year. UBED is a safe and innovative alternative choice for treatment of LDH at L5/S1 level.

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Objective: Bone cement releases a large amount of heat as it polymerizes. Skin burns caused by discarded bone cement are not well understood during arthroplasty. It is important to study the correlates and mechanisms of scalding and to accurately evaluate the severity of burns to guide treatment decisions.Methods: Standardized burns were created in eight anesthetized rabbits using different thicknesses of bone cement.Bone cement was uniformly stirred to make thicknesses of 1 mm, 4 mm, 8 mm, 12 mm, 16 mm, and 20 mm and a 20 Â 40 mm cuboid. Bone cement samples were then placed on the back of a rabbit, and the temperature changes were recorded with an industrial digital thermometer. One hour later, the appearance of scalded skin was observed, and the rabbits were euthanized. The scalded parts were cut to make pathological sections and stained with HE, and the differences in the depth of the scalded skin caused by different thicknesses of bone cement were observed under a light microscope.Results: Damage caused by 1 mm-, 4 mm-, 8 mm-, 12 mm-, 16 mm-, and 20 mm-thick bone cement samples mainly involved the epidermis, the papillary dermis, the reticular dermis layer, and the full thickness of the skin and the subcutaneous tissue. The maximum temperature of 1 mm, 4 mm, 8 mm, and 12 mm bone cementation had a statistically significant difference (p < 0.001), while there was no significant difference between 12 mm, 16 mm, and 20 mm samples (p = 0.856). The time to severe scalding with bone cement at temperatures above 70 C was significantly different between different thicknesses (p < 0.001). Conclusion:The heat released by different thicknesses of bone cement leads to different maximum temperatures and the duration of severe burns, resulting in different degrees of skin burns. Attention should be paid to discarded bone cement to prevent this potential complication in knee arthroplasty.