[Comparison of the efficacy of LARS ligament and autogenous hamstring tendon plus high-strength suture in posterior cruciate ligament reconstruction].

OBJECTIVE: To compare the clinical efficacy of ligament advanced reinforcement system (LARS) and autogenous hamstring tendon plus high-strength suture in arthroscopic reconstruction of posterior cruciate ligament(PCL). METHODS: A total of 96 patients with simple PCL injury treated with arthroscopic posterior cruciate ligament reconstructive surgery admitted to our hospital between August 2019 and December 2021 were selected for complete follow-up. There were 78 males and 18 females, 40 cases of left leg and 56 cases of right leg, the aged from 20 to 56 years old with an average of (32.50±8.68 ) years old. The transplants were divided into two groups:LARS group (52 cases) and autogenous hamstring tendon plus high-strength suture group (44 cases). In the LARS group, there were 42 males and 10 females;with an average age of (31.84±8.62) years old;body mass index (BMI) was (24.73±2.29) kg﹒m-2;7 mm LARS was used to reconstruct PCL. In the autologous tendon group, there were 36 males and 8 females, with an average age of (33.06±8.99) years old, BMI was (23.52±2.16) kg·m-2, and the PCL was reconstructed with four strands of hamstring tendons and three pieces of Ethibond suture. All patients underwent functional rehabilitation guided exercise and were followed up regularly after surgery to objectively evaluate the stability of the knee joint by KT-1000 measurement of knee relaxation, and subjective evaluation of knee function by Lysholm score, Tegner score, and International Knee Documentation Council (IKDC) score. Data from preoperative, 3, 6, and 12 month follow-up were collected and analyzed by SPSS software to compare postoperative recovery and ligament relaxation between the two groups of patients. RESULTS: Ninety-six patients were followed up for 12 months. KT-1000 measurement of knee joint in autogenous tendon group and LARS group before operation [(10.73±1.46) points vs (10.55±1.53) points], 6 months after operation[(3.02±0.75) points vs (2.35±0.60) points], 12 months after operation[(3.77±1.76) points vs (2.44±0.60) points]. There was significant difference between the two groups at 6 and 12 months after operation (P<0.05), but there was no significant difference between the two groups at 3 months after operation (P>0.05). In the autogenous tendon group and LARS group, before operation and 12 months after operation, total Lysholm score [(40.6±16.8), (91.25±6.35) points vs (51.92±18.52), (92.35±5.30) points], Tegner score[(1.8±0.7), (5.8±0.6) points vs(1.7±0.8)、(5.7±0.7) points] and total IKDC score[(54.50±6.33), (83.90±3.93) points vs (54.40±4.24), (83.62±3.64) points], the differences were statistically significant (P<0.05), indicating that the knee function of the two groups was improved after surgery. At 3 and 6 months after operation in the autogenous tendon group and LARS group, the total Lysholm score[(65.86±11.54), (74.60±6.46) points vs (73.46±6.42), (86.73±4.62) points], Tegner score[(2.5±0.6), (3.5±0.5) points vs (4.3±0.7), (5.0±1.4) points], the total scores of IKDC [(55.78±2.68), (70.62±4.74) points vs (65.31±4.60), (79.71±2.93) points]. The difference between two groups was statistically significant (P<0.05). The results showed that the function of the knee joint in the LARS group was better than that the autologous tendon group. However, at 12 months after the operation, there was no significant difference in the score of knee joint function between the two groups (P>0.05). The results showed that the stability of LARS group was better than that of autologous tendon group. CONCLUSION: Both the autogenous hamstring tendon plus high-strength suture and LARS reconstruction can significantly improve the knee function and stability, with satisfactory postoperative results. Howervr the LARS provides superior postoperative stability.

Porous Carbon Membrane-Supported Atomically Dispersed Pyrrole-Type FeN4 as Active Sites for Electrochemical Hydrazine Oxidation Reaction.

The rational design of catalytically active sites in porous materials is essential in electrocatalysis. Herein, atomically dispersed Fe-Nx sites supported by hierarchically porous carbon membranes are designed to electrocatalyze the hydrazine oxidation reaction (HzOR), one of the key techniques in electrochemical nitrogen transformation. The high intrinsic catalytic activity of the Fe-Nx single-atom catalyst together with the uniquely mixed micro-/macroporous membrane support positions such an electrode among the best-known heteroatom-based carbon anodes for hydrazine fuel cells. Combined with advanced characterization techniques, electrochemical probe experiments, and density functional theory calculation, the pyrrole-type FeN4 structure is identified as the real catalytic site in HzOR.