LARS韧带联合半关节置换治疗儿童膝关节周围恶性肿瘤的初步研究

Preliminary research of combining LARS and semi-joint replacement for malignant tumor around the knee in children

目的研究韧带增强重建系统（ligament advanced reinforcement system, LARS ）联合半关节置换治疗儿童膝关节周围恶性肿瘤初步临床疗效。方法回顾性分析2015年02月至2017年05月收治的9例膝关节周围恶性肿瘤患儿的病例资料，男5例，女4例；年龄5-12岁，平均9．2岁；随访时间6-28个月，平均13．5个月。术前病理诊断为尤文肉瘤3例、骨肉瘤6例，Enneking分期均ⅡB期。所有患者均按时接受规范的术前新辅助化疗，均接受肿瘤广泛切除及假体置换手术。根据术前CT、MRI确选择合适长度组配假体，韧带环形捆绑假体后并与残余交叉韧带、侧副韧带、关节囊及肌肉等缝合，重建于假体上。术后均给予辅助化疗及功能锻炼。随访骨折愈合、下肢发育及并发症等情况，并根据美国肌肉骨骼肿瘤学会（Musculoskeletal Tumor Society, MSTS）评分系统评分及双膝关节活动度（range of motion，ROM）进行功能评定。结果9例均顺利完成术后化疗，化疗中骨髓抑制均得到恢复，无其他严重化疗并发症。伤口均一期愈合。9例步态良好无明显跛行；下肢不等长为0．5～6．4cm，平均（2．9±1．8）em；股骨相差0．6～3．9cm，平均（1．9±1．O）cm，胫骨相差0．2-2．0cm，平均（0．8±0．5）cm。力线偏离膝关节中心距离为0．2-0．6cm，平均（0．3±0．1）cm；末次随访MSTS评分为（24．6±3．2）分，术前为（21．4±1．9）分，差异有统计学意义（t=2．71，P=0．03）；末次随访膝关节ROM为71．7°±18．2°，术前为69．1°±17．9°，差异有统计学意义（t=3．261，P=0．01）。本组无感染、脱位、骨折、似体断裂、假体松动等并发症，2例出现肺部转移，均带瘤牛存，无其他肿瘤转移或复发。结论LARS韧带联合半关节似体置换治疗儿童膝关节周同恶性肿瘤，术后关节功能恢复满意、手术操作简单、并发症少，保留对侧骨骺最大程度减少肢体不等长发生，但远期疗效需进一步随访。

Objective To study the preliminary effect of combining ligament advanced reinforcement system （LARS） and semi-joint replacement for malignant tumor around the knee in children. Methods 9 cases of malignant tumor around the knee （5 boys and 4 girls） from February 2015 to May 2017 were analyzed respectively. The average age was 9.2 years old （ranged from 5 to 12 years）. The follow-up time was 6 to 28 months, with an average of 13.5 months. The preoperational biopsy diagnosis respec- tively were Ewing sarcoma （3 eases） and osteosareoma （6 cases）. According to Enneking staging system, all 9 cases were staged as liB. The planned courses of standardized preoperative neoadjuvant chemotherapy were successfully given to all patients on time. All patients were given tumor extensive resection and modular prosthesis replacement. Suitable length prosthesis were prepared ac- cording to CT and MRI. LARS were annularly bundled to the prosthesis. Then residual patella ligaments, erueiate ligaments, collat- eral ligaments, capsules and muscles were tightly sutured to LARS. Adjuvant chemotherapy and functional exercise were given af- ter operation. Bone healing, limb discrepancy, and complications were regularly recorded. Functional outcomes were assessed by the system of the Museuloskeletal Tumor Society （MSTS） and the range of motion fROM） of both knee joints. Results All patients successfully received standardized chemotherapy. In all courses of chemotherapy, bone marrow all restored. No other major compli- cations occurred during chemotherapy. Primary healing of incisions were obtained. No obvious limb discrepancy. The average limb length discrepancy was 2.9±1.8 em （0.5-6.4 cm）, the femur was 1.9±1.0 cm （0.6±3.9 em）, the tibia was 0.8±0.5 cm （0.2-2.0 em）. The distance between the lower limb aligmnent and the center of the knee was 0.3 ±0.1 cm （0.2±0.6 cm）. MSTS score was 24.6±3.2 of the last follow-up, and 21.4±1.9 of preoperation, the difference was statistically significant （t=2.71, P=0.03）. ROM of the knee were 71.7°±18.2° at the last follow-up, and 69.1°±17.9° before operation, and the difference was statistically significant （t=3.261, P=0.01）. No infection, snapping knee, limp, dislocation, periprosthesis fractures, prosthetic broken or loosening. 2 case had lung metastasis and still survived. NO local recurrence or other metastasis cases. Conclusion LARS combined with semijoint replacement for the treatment of malignant tumor around the knee in children have a satisfactory postoperative joint function recovery and simple surgical technique and fewer complications, and preserve the contralateral osteophytes to minimize the occurrence of limb inequality, but the long-term efficacy needs further follow-up.