胫骨机械轴定位器在伴胫骨关节外畸形的人工全膝关节置换术中的应用

APPLICATION OF TIBIAL MECHANICAL AXIS LOCATOR IN TIBIAL EXTRA-ARTICULAR DEFORMITY IN TOTAL KNEE ARTHROPLASTY

目的探讨自制胫骨机械轴定位器在伴胫骨关节外畸形的人工全膝关节置换术(total kneearthroplasty,TKA)中改善胫骨下肢力线的应用价值。方法 2012年1月-8月,收治13例21膝伴胫骨关节外畸形的骨性关节炎患者。男5例8膝,女8例13膝;年龄58～78岁,平均66.5岁。病程2～5年,平均3.5年。膝关节学会评分系统(KSS)评分为(45.5±15.5)分。膝关节外翻1例2膝,内翻12例19膝。术前摄双下肢全长X线片,患者均存在10～21°胫骨关节外内、外翻弓状畸形。术前应用自制胫骨机械轴定位器,在X线透视下确定并标记冠状位胫骨机械轴。术中使用胫骨髓外定位装置根据标记的机械轴进行截骨。结果术后切口均Ⅰ期愈合,无感染及关节不稳等并发症发生。患者均获随访,随访时间5～12个月,平均8.3个月。术后第3天X线片检查示,1例1膝偏差角为2.9°,余均<2°,力线准确率达95.2%;随访期间无假体松动及不稳发生。末次随访时,患者膝关节功能KSS评分为(85.5±15.0)分,与术前比较差异有统计学意义(t=12.82,P=0.00)。结论自制胫骨机械轴定位器可提高伴胫骨关节外畸形的TKA术中胫骨下肢力线的准确率。

Objective To explore the application value of self-made tibial mechanical axis locator in tibial extra-articular deformity in total knee arthroplasty （TKA） for improving the lower extremity force line. Methods Between January and August 2012, 13 cases （21 knees） of osteoarthritis with tibial extra-articular deformity were treated, including 5 males （8 knees） and 8 females （13 knees） with an average age of 66.5 years （range, 58-78 years）. The disease duration was 2-5 years （mean, 3.5 years）. The knee society score （KSS） was 45.5 ± 15.5. Extra-articular deformities included 1 case of knee valgus （2 knees） and 12 cases of knee varus （19 knees）. Preoperative full-length X-ray films of lower extremities showed 10-21° valgus or varus deformity of tibial extra joint. Self-made tibial mechanical axis locator was used to determine and mark coronal tibial mechanical axis under X-ray before TKA, and then osteotomy was performed with extramedullary positioning device according to the mechanical axis marker. Results All incisions healed by first intention, without related complications of infection and joint instability. All patients were followed up 5-12 months （mean, 8.3 months）. The X-ray examination showed 〈 2° knee deviation angle in the others except 1 case of 2.9° knee deviation angle at 3 days after operation, and the accurate rate was 95.2%. No loosening or instability of prosthesis occurred during follow-up. KSS score was 85.5 ± 15.0 at last follow-up, showing significant difference when compared with preoperative score （t=12.82, P=0.00）. Conclusion The seft-made tibial mechanical axis locator can improve the accurate rate of the lower extremity force line in TKA for tibia extra-articular deformity.