探讨双钢板内固定治疗肱骨远1/3骨折的生物力学特性及其对肘关节功能和肘关节活动度的影响。

选取本院2020年1月至2022年12月收治的160例肱骨远1/3骨折患者，随机分为传统内固定组（n=80）和双钢板内固定组（n=80），比较两组患者的手术指标、术后肘关节功能Mayo评分、肘关节评分、并发症发生率以及肩关节功能改善情况。采用人工骨建立肱骨远端C1型骨折模型，分别采用传统内固定和双钢板内固定，通过特定的软件进行建模，模拟生物力学的各种测试，进行有限元分析。依据术后Mayo评分将患者分为优良组（≥75分）和非优良组（<75分），分析两组患者的基本资料，Logistic回归分析影响患者手术疗效的因素。

双钢板内固定组的切口长度、手术时间、术中出血量、骨折愈合时间均显著低于传统内固定组（P<0.05）。双钢板内固定组的术后肘关节功能Mayo评分、肘关节活动度、肘关节评分、肩关节功能改善情况均显著高于传统内固定组（P<0.05）。双钢板内固定组的并发症发生率（6.25%）显著低于传统内固定组（21.25%，P<0.05）。有限元分析结果显示，双钢板内固定组的应力分布更均匀，应变能量密度更低，骨折稳定性更高，骨折愈合速度更快。Logistic分析结果显示，影响患者手术疗效的因素有年龄、性别、骨折类型、内固定方式、术中出血量、骨折愈合时间、并发症发生率等，其中内固定方式是最重要的影响因素（OR=8.32，95% CI：2.54~27.28，P<0.01）。

双钢板内固定治疗肱骨远1/3骨折具有良好的生物力学特性，能有效提高骨折稳定性，促进骨折愈合，改善肘关节功能和肘关节活动度，降低并发症发生率，是一种安全、有效、可靠的治疗方法。

The distal 1/3 fracture of the humeral shaft refers to the fracture from below the middle part to 2 cm above the condyle of the humerus. The structural and anatomical characteristics of the distal 1/3 of the humeral shaft make it a prone site for fracture. As the aging of society progresses, about 85% of the patients occur in people over 50 years of age, with the incidence peaking in the 60-90-year age group. For distal humerus fractures, non-surgical methods such as upper limb suspension fixation usually result in good treatment if there is no significant displacement. However, for severely displaced or comminuted fractures, surgical treatment with locking plate internal fixation is usually more effective. However, there are inconsistent conclusions about the clinical effectiveness of different internal fixation procedures, which increases the difficulty of selecting an appropriate clinical treatment strategy. The efficacy varies, especially in treating distal humerus 1/3 fracture with double plate internal fixation. Therefore, it is essential to analyze the factors affecting the therapeutic effect based on clinical data, evaluate the prognosis of patients accordingly, and provide timely and reasonable treatment to improve the quality of life of patients with distal humerus 1/3 fracture.

To investigate the biomechanical characteristics of double plate internal fixation in treating distal humerus 1/3 fracture and its effect on elbow joint function and elbow joint motion.

A total of 160 patients with distal 1/3 fracture of the humerus admitted to our hospital from January 2020 to December 2022 were randomly divided into a traditional internal fixation group (80 cases) and a double plate internal fixation group (80 cases) . The two groups’ surgical indicators, postoperative Mayo score of elbow function, elbow joint score, complication rate, and improvement of shoulder joint function were compared. The C1 fracture model of the distal humerus was established using artificial bone. Traditional internal fixation and double plate internal fixation were used, respectively. The model was modeled using special software, various biomechanical tests were simulated, and finite element analysis was performed. The patients were divided into the excellent group (≥75 points) and the non-excellent group (<75 points) according to the postoperative Mayo score. The primary data of the two groups were analyzed, and the factors affecting the surgical efficacy of the patients were analyzed using logistic regression.

The incision length, operation time, intraoperative blood loss, and fracture healing time in the double-plate internal fixation group were significantly lower than those in the traditional internal fixation group (P<0.05) . The improvement of elbow joint function Mayo score, elbow joint motion, elbow joint score, and shoulder joint function in the double-plate internal fixation group were significantly higher than in the traditional internal fixation group (P<0.05) . The complication rate of the double plate internal fixation group (6.25%) was significantly lower than that of the traditional internal fixation group (21.25%) (P<0.05) . The finite element analysis results showed that the stress distribution was more uniform, the strain energy density was lower, the fracture stability was higher, and the fracture healing speed was faster in the double-plate internal fixation group. Logistic analysis showed that age, gender, fracture type, internal fixation mode, intraoperative blood loss, fracture-healing time, and complication rate were the most important factors influencing the surgical outcome of patients (OR=8.32, 95% CI=2.54-27.28, P<0.01) .

The treatment of distal 1/3 humerus fracture with double plate internal fixation has good biomechanical properties, can effectively improve fracture stability, promote fracture healing, improve elbow joint function and elbow joint motion, and reduce the incidence of complications. It is a safe, effective, and reliable treatment method.