Li X, Ma SH, Gong HL, Wen J, Li FL, Xiao S. Surface electromyography signal characteristics of lower limb muscles in children with unilateral developmental dysplasia of the hip. World J Orthop 2026; 17(3): 115251 [DOI: 10.5312/wjo.v17.i3.115251]
Corresponding Author of This Article
Sheng Xiao, Consultant, Department of Pediatric Orthopedics, Hunan Provincial People’s Hospital, The First Affiliated Hospital of Hunan Normal University, No. 61 Jiefang West Road, Furong District, Changsha 410013, Hunan Province, China. 153816333@qq.com
Research Domain of This Article
Pediatrics
Article-Type of This Article
Retrospective Study
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This article is an open-access article which was selected by an in-house editor and fully peer-reviewed by external reviewers. It is distributed in accordance with the Creative Commons Attribution Non Commercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited and the use is non-commercial. See: http://creativecommons.org/licenses/by-nc/4.0/
Mar 18, 2026 (publication date) through Mar 16, 2026
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Journal Information of This Article
Publication Name
World Journal of Orthopedics
ISSN
2218-5836
Publisher of This Article
Baishideng Publishing Group Inc, 7041 Koll Center Parkway, Suite 160, Pleasanton, CA 94566, USA
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Li X, Ma SH, Gong HL, Wen J, Li FL, Xiao S. Surface electromyography signal characteristics of lower limb muscles in children with unilateral developmental dysplasia of the hip. World J Orthop 2026; 17(3): 115251 [DOI: 10.5312/wjo.v17.i3.115251]
Xin Li, Sheng-Hong Ma, Hao-Li Gong, Jie Wen, Fan-Ling Li, Sheng Xiao, Department of Pediatric Orthopedics, Hunan Provincial People’s Hospital, The First Affiliated Hospital of Hunan Normal University, Changsha 410013, Hunan Province, China
Co-first authors: Xin Li and Sheng-Hong Ma.
Co-corresponding authors: Fan-Ling Li and Sheng Xiao.
Author contributions: Li X contributed to conceptualization; Ma SH contributed to investigation; Gong HL contributed to formal analysis; Wen J contributed to methodology; Li FL contributed to % curation; Xiao S contributed to supervision; Li X and Ma SH contributed equally to this manuscript and are co-first authors; Li FL and Xiao S contributed equally to this manuscript and are co-corresponding authors. All authors approval the final manuscript.
Supported by the General Guidance Project of Scientific Research Topics of Hunan Provincial Health Commission, No. 202204073270.
Institutional review board statement: This study was approved by the Ethics Committee of Hunan Provincial People’s Hospital, The First Affiliated Hospital of Hunan Normal University (Approval No.[2025]-298). All procedures performed in studies involving human participants were in accordance with the ethical standards of the institutional research committee and with the Declaration of Helsinki and its later amendments or comparable ethical standards.
Informed consent statement: The authors affirm that human research participants provided informed consent for publication. All study participants, or their legal guardian, provided informed written consent prior to study enrollment.
Conflict-of-interest statement: All the authors report no relevant conflicts of interest for this article.
Data sharing statement: The datasets used and/or analyzed during the current study are available from the corresponding author on reasonable request.
Corresponding author: Sheng Xiao, Consultant, Department of Pediatric Orthopedics, Hunan Provincial People’s Hospital, The First Affiliated Hospital of Hunan Normal University, No. 61 Jiefang West Road, Furong District, Changsha 410013, Hunan Province, China. 153816333@qq.com
Received: October 17, 2025 Revised: November 12, 2025 Accepted: February 4, 2026 Published online: March 18, 2026 Processing time: 151 Days and 6.8 Hours
Abstract
BACKGROUND
Closed reduction and Salter osteotomy are commonly used to treat children with developmental dysplasia of the hip (DDH). However, it remains unclear whether the muscle activity of the lower extremities returns to normal or shows compensation and imbalance after surgery.
AIM
To evaluate changes in surface electromyography (EMG) signals of the main muscles in both lower limbs of children with unilateral DDH during standing and walking after closed reduction surgery or Salter osteotomy. We also aimed to quantify the differences in bilateral muscle activation and explore the characteristics of surface EMG signals of the muscles around the hip joint and the postoperative rehabilitation effects.
METHODS
The retrospective analysis was conducted on 59 children with unilateral DDH who received treatment in the pediatric orthopedics department of a single tertiary grade A hospital. Twenty-eight children underwent closed reduction and 31 children underwent Salter osteotomy combined with femoral shortening and rotational correction osteotomy. Surface EMG was used to compare the average root mean square (RMS) values, coordination ratio, and the ratio of the RMS values between the affected and healthy sides in the bilateral tensor fasciae latae, rectus femoris, medial hamstring, anterior tibialis, medial gastrocnemius, and gluteus maximus muscles during standing and walking at the final follow-up. Outcomes were further evaluated using the Harris hip score and the modified Severin classification.
RESULTS
The average follow-up period was 51.64 ± 34.85 months for the closed reduction group and 51.0 ± 34.76 months for the Salter osteotomy group. The average Harris score was 95.91 ± 1.01 in the Salter osteotomy group, which was lower than that of the closed reduction group (98.84 ± 0.82; P < 0.05). During walking, compared with the closed reduction group, the Salter osteotomy group showed significantly higher mean RMS values in the tensor fasciae latae on both the affected and healthy sides and in the rectus femoris on the affected side (P < 0.05). In addition, the synergistic contraction between the rectus femoris muscle and hamstring muscles was significantly increased (P < 0.05).
CONCLUSION
At the mid-term follow-up after surgery, the closed reduction and Salter osteotomy groups both achieved good functional scores and imaging results. However, during walking, muscle electrical activity of the tensor fasciae latae and rectus femoris on the affected side was increased in the Salter osteotomy group, suggesting that targeted postoperative rehabilitation exercises are warranted.
Core Tip: Closed reduction and Salter osteotomy are commonly used to treat children with developmental dysplasia of the hip. However, it remains unclear whether the muscle activity of the lower extremities returns to normal or shows compensation and imbalance after surgery. The aim of this study was to evaluate the changes in surface electromyography signals of the main muscles in both lower limbs of children with unilateral developmental dysplasia of the hip during standing and walking after closed reduction surgery or Salter osteotomy. We also aimed to quantify the differences in bilateral muscle activation and explore the characteristics of surface electromyography signals of the muscles around the hip joint and the postoperative rehabilitation effects.
