Department of Pediatric Orthopedics, Chang Gung Memorial Hospital, Chang Gung University, Taoyuan, Taiwan.
J Pediatr Orthop. 2022 Apr 1;42(4):e384-e389. doi: 10.1097/BPO.0000000000002076.
Distal femur extension osteotomy (DFEO) is a common treatment for knee flexion contracture and crouch gait in patients with cerebral palsy (CP), but skeletally immature patients tend to develop genu valgum deformities after DFEO. This study aimed to report the tendency of valgus changes after DFEO and determine the risk factors for subsequent surgery for excessive genu valgum.
This retrospective case-control study included 25 children with CP who underwent DFEO in 44 limbs for knee flexion contractures ≥15 degrees at a mean age of 11.0 years. Radiologic measurements included the anatomic lateral distal femoral angle (aLDFA), anatomic tibiofemoral angle (aTFA), medial proximal tibia angle, and plate-condyle angle, postoperatively and at the latest follow-up. Age, sex, preoperative knee flexion contracture angle, Gross Motor Function Classification System level, and radiographic measurements were compared between children with and without subsequent guided growth for genu valgum.
A significant valgus change was observed at the distal femur in the first postoperative year (aLDFA from 83.6 to 80.1 degrees, P<0.001; aTFA from 176.1 to 172.5 degrees, P<0.01; plate-condylar angle from 5.3 to 9.5 degrees, P<0.001). Valgus changes occurred in 36 of the 44 limbs (82%) by an average of -4.6 degrees in the aLDFA, and subsequent guided growth was performed in 5 patients (20%). Guided growth for genu valgum was associated with a greater postoperative valgus angle (aLDFA: 78.0 vs. 84.9 degrees, P<0.01) but not with age, Gross Motor Function Classification System level, or preoperative flexion contracture.
Distal metaphyseal osteotomies and distally placed angled plates near the physis are associated with valgus changes following growth. We recommend making a slight varus alignment during DFEO to compensate for subsequent valgus changes.
Level III-therapeutic, retrospective comparative study.
股骨远端延长截骨术（DFEO）是治疗脑瘫（CP）患者膝关节屈曲挛缩和蹲伏步态的常用方法，但在骨骼未成熟的患者中，DFEO 后往往会出现膝内翻畸形。本研究旨在报告 DFEO 后发生外翻变化的趋势，并确定随后因过度膝内翻行手术治疗的危险因素。
本回顾性病例对照研究纳入了 25 名 CP 患儿，44 条肢体因膝关节屈曲挛缩≥15°行 DFEO，平均年龄为 11.0 岁。影像学测量包括解剖外侧远端股骨角（aLDFA）、解剖胫骨股骨角（aTFA）、内侧胫骨近端角和钢板-髁突角，术后和末次随访时进行测量。比较了膝内翻畸形的儿童与未行后续引导生长的儿童的年龄、性别、术前膝关节屈曲挛缩角度、粗大运动功能分类系统（GMFCS）分级和影像学测量结果。
术后第一年观察到远端股骨明显的外翻变化（aLDFA 从 83.6°变为 80.1°，P<0.001；aTFA 从 176.1°变为 172.5°，P<0.01；钢板-髁突角从 5.3°变为 9.5°，P<0.001）。44 条肢体中有 36 条（82%）出现平均-4.6°的 aLDFA 外翻变化，其中 5 名患者（20%）行后续引导生长治疗。膝内翻畸形的引导生长与术后更大的外翻角度（aLDFA：78.0°比 84.9°，P<0.01）相关，而与年龄、GMFCS 分级或术前的屈曲挛缩无关。
骺端截骨术和骺板附近的远端成角钢板与生长后的外翻变化有关。我们建议在 DFEO 时做轻微的内翻对线，以补偿随后的外翻变化。
III 级-治疗性回顾性比较研究。
