Hospital for Special Surgery, New York, NY, USA.
Seoul Foot and Ankle Center, Dubalo Orthopaedic Clinic, Seoul, Republic of Korea.
Foot Ankle Int. 2022 Apr;43(4):474-485. doi: 10.1177/10711007211050639. Epub 2021 Oct 23.
The dome-type osteotomy is a powerful technique for deformity correction of the limb. However, there is limited information about the utility of dome supramalleolar osteotomy (SMO) in ankle joint preservation surgery. This study aimed to describe the technique and indications for dome SMO in distal tibial malalignment.
Twenty-three patients (23 ankles) who underwent dome SMO with a 2-year follow-up were reviewed. Dome SMO was indicated when there were opposing deformities in the ankle and lower limb mechanical axis (ie, varus ankle deformity with valgus lower limb alignment and vice versa) where inherent translation following conventional wedge-type osteotomies could worsen the deformity of the entire lower limb. Patients were divided into 2 groups based on preoperative ankle alignment: the varus ankle group (n = 11) and the valgus ankle group (n = 12). The radiographic correction was assessed using 6 parameters from weightbearing ankle and hindfoot alignment views. In addition, the lower limb mechanical axis was assessed with ankle center deviation (ACD) from the hip-knee (HK) line on the whole limb radiograph, and the weightbearing line (WBL) point was measured to identify changes in the weightbearing load within the ankle joint.
Preoperatively, the varus ankle group had varus ankle deformity (tibiotalar angle [TTA], 76.5 ± 5.8 degrees) with valgus lower limb mechanical axis, whereas the valgus ankle group had valgus ankle deformity (TTA, 99.1 ± 4.5 degrees) with varus lower limb mechanical axis alignment. Postoperatively, a significant improvement in the ankle alignment and the lower limb mechanical axis was observed in both groups. The ACD significantly changed toward the HK line, suggesting an improved lower limb mechanical axis, and the WBL point showed a significant shift of the weightbearing axis toward the uninvolved area within the ankle joint.
Dome SMO demonstrated a successful correction of local deformity while simultaneously realigning the hip-knee-ankle axis toward neutral. Additionally, an effective load shifting toward an uninvolved area within the ankle joint was observed.
Level IV, case series.
穹顶式截骨术是矫正肢体畸形的有力技术。然而，关于踝关保留手术中穹顶距下骨切开术（SMO）的应用信息有限。本研究旨在描述胫骨远端对线不良时穹顶 SMO 的技术和适应证。
回顾性分析了 23 例（23 足）接受穹顶 SMO 治疗并随访 2 年的患者。当踝和下肢机械轴存在相反的畸形（即内翻踝畸形伴下肢对线外旋，反之亦然），且常规楔形截骨术后的固有平移可能加重整个下肢的畸形时，考虑行穹顶 SMO。根据术前踝关节对线，将患者分为 2 组：内翻踝组（n=11）和外翻踝组（n=12）。采用负重位踝关节和后足对线片的 6 项参数评估放射学矫正情况。此外，通过下肢全长片上的踝中心偏离（ACD）从髋膝（HK）线评估下肢机械轴，测量负重线（WBL）点以确定踝关节内负重负荷的变化。
术前，内翻踝组有内翻踝畸形（距骨跟骨角[TTA]，76.5±5.8 度）伴下肢机械轴外旋，而外翻踝组有外翻踝畸形（TTA，99.1±4.5 度）伴下肢机械轴内旋。术后，两组踝关节对线和下肢机械轴均有显著改善。ACD 明显向 HK 线靠拢，提示下肢机械轴得到改善，WBL 点显示负重轴向踝关节未受累区域明显转移。
穹顶 SMO 成功矫正了局部畸形，同时使髋膝踝轴向中立位重新对线。此外，还观察到踝关节内未受累区域的有效负荷转移。
IV 级，病例系列。
