[Correlational between the gap contact force and the degree of lower limb alignment correction in Oxford mobile bearing unicompartmental knee arthroplasty].

Objective: To study the correlation between joint contact force and postoperative lower extremity alignment in Oxford unicompartmental knee arthroplasty (OUKA) and provide reference data for predicting the lower extremity alignment after OUKA. Methods: It was a retrospective case series study. A total of 78 patients (92 knees) who underwent OUKA surgery from January 2020 to January 2022 in the Department of Orthopedics and Joint Surgery of China-Japan Friendship Hospital were included in this study, including 29 males and 49 females, aged (68.8±6.9) years. A custom-designed force sensor was used to measure gap contact force in the medial gap of OUKA. The patients were divided into groups according to the varus degree of lower limb alignment after operation. Relationship between the gap contact force and the alignment of the lower limbs after operation was analyzed with Pearson correlation analysis, and the gap contact force was compared between patients with different lower limbs alignment correcting results. Results: The mean contact force measured during the operation at 0° of knee extension was 81.7 N±57.8 N, and it was 96.1 N±54.5 N at 20° of knee flexion. The average postoperative knee varus angle was 2.9°±2.7°. The gap contact force at the 0° and 20° positions of the knee joint was negatively correlated with the varus degree of the postoperative lower limb alignment (r=-0.493, -0.331, both P<0.001). The distribution of gap contact force at 0° was different in each group, the contact force [M (Q1, Q3)] of the neutral position group(n=24) was 117.4 N (31.7 N, 233.0 N), and it was 63.7 N (11.3 N, 209.0 N), 31.5 N (8.3 N, 87.7 N) in the mild varus group (n=51) and the significant varus group (n=17), respectively, and the difference was statistically significant (P<0.001); while at 20°, only the difference between the significant varus group and the neutral position group was statistically significant (P=0.040). The gap contact force of the alignment satisfactory group at 0° and 20° was greater than those in the significant varus group (both P<0.05). The gap contact force measured at 0° and 20° was significantly greater in patients with preoperative significant flexion deformity than in patients without flexion deformity (or mild flexion deformity) (both P<0.05). Conclusions: OUKA gap contact force is related to the degree of lower limb alignment correction after the operation. In patients with well-corrected lower limb alignment after surgery, the median intraoperative knee joint gap contact force at 0° and 20° is 117.4 N and 92.5 N, respectively.

[Ferroptosis in laryngeal squamous cell carcinoma and its regulation by M2 macrophage-derived exosomes].

Objective: To investigate ferroptosis in laryngeal squamous cell carcinoma (LSCC) and its regulation by M2 macrophage-derived exosomes. Methods: LSCC and adjacent noncancerous tissue samples were collected from 32 patients treated in the Department of Otorhinolaryngology, Head and Neck Surgery of the Second Affiliated Hospital of Harbin between September 2018 and April 2021, including 26 males and 6 females, aged 43-79 years. The expressions of ferroptosis marker glutathione peroxidase 4(GPX4) in LSCC and adjacent noncancerous tissues were detected by immunohistochemistry and reverse transcriptase-polymerase chain reaction(RT-PCR). The correlations between GPX4 expression and clinicopathological factors in LSCC were analyzed. Biological changes of TU212 cells after treated with ferroptosis-induced agent erastin were detected by transmission electron microscope, cell counting kit-8(CCK-8), clone test, reactive oxygen species(ROS), malondialdehyde(MDA), glutathione(GSH), JC-1, RT-PCR and western blot. Exosomes were isolated from the supernatant of M0/M2 macrophages (M0-exos/M2-exos) and co-incubated with erastin-treated TU212 cells to detect the change of ferroptosis in cells of each group. The data were analyzed by SPSS software of version19.0. Results: GPX4 expression in LSCC tissues was significantly higher than that in adjacent noncancerous tissues (2.04±0.65 vs. 0.99±0.09, F=30.36, P<0.001), and was closely related to T stage and clinical stage (Ⅰ-Ⅱvs.Ⅲ-Ⅳ: 1.75±0.39 vs. 2.18±0.71, F=2.25, P<0.05; T1-2 vs. T3-4: 1.71±0.42 vs. 2.20±0.69, F=2.06, P<0.05). In TU212 cells treated with erastin, mitochondrial crest became smaller, membrane density increased, proliferation rate decreased, intracellular ROS level increased, mitochondrial membrane potential depolarized, GSH content decreased, intracellular MDA level increased and expressions of GPX4 mRNA and protein decreased. Change of M0 into M2 macrophages was induced by IL-4 stimulation. When erastin-treated TU212 cells were incubated with M2-exos, cell proliferation was partially restored and GPX4 expression was enhanced, and also with the recoveries of levels of ROS, MDA and GSH (all P<0.05). Conclusions: Ferroptosis is one of the cell death ways of LSCC. M2-exos may inhibit ferroptosis of LSCC cells.

[Application of rigid curved laryngoscope in the examination of hypopharynx and the treatment of early hypopharyngeal cancer].

Objective: To evaluate the efficacy of curved suspension laryngoscope assistant transoral surgery (CLATOS) in the examination of hypopharynx, and diagnosis and surgery of early hypopharyngeal carcinoma. Methods: Thirty-four patients who underwent detailed examination for lower part of hypopharynx and surgery for early hypopharyngeal carcinoma with CLATOS technique in the Second Affiliated Hospital of Harbin Medical University from January 2019 to January 2020 were analyzed retrospectively. The age ranged from 42 to 74 years old including 28 males and 6 females. Among them, 25 patients complaining of foreign body sensation in the pharynx for more than half a year with a poor exposure of the lower pharynx in the examination with flexible laryngoscope in the outpatient department were admitted to the hospital for the further examination with rigid curved laryngoscopy and 9 patients with stage T1-2 hypopharyngeal squamous cell carcinoma were operated with CLATOS technique. Preoperative, intraoperative and postoperative data were analized. Results: One case of squamous cell carcinoma in esophageal entrance (T1N0M0) and one case of carcinoma in pyriform sinus (T1N0M0) with cervical esophageal carcinoma (T1N0M0) were found in the 25 patients with foreign body sensation in the pharynx. En bloc resection of cancer was obtained in 9 patients with stage T1-2 hypopharyngeal carcinomas and 2 of them underwent tracheotomy. One patient with T1 retrocricoid carcinoma was found to have a carcinoma in situ at the lower part of posterior hypopharyngeal wall in the examination during follow-up, which was resected simultaneously. Postoperatively this patient developed a stenosis in the esophageal entrance, which was dilated twice until swallowing normally. Two patients of T2N0M0 and one of T2N1M0 underwent bilateral neck lymph node dissection just after the removal of primary tumors. During follow-up, none of the 9 patients showed tumor recurrence and complications such as dysphonia and dyspnea. Conclusion: CLATOS technique can provide a promising way in the examination of hypopharynx and the detection of early lesions of hypopharynx and esophageal entrance, and this technique has also the advantages such as full visual angle and easy operation for the resection of early hypopharyngeal carcinoma. The quality of life of patients can be improved while the tumor is removed en bloc with this technique.