Junchao Guo1, Lizhen Wang2, Rui Mao2, Cheng Chang3, Jianmin Wen4, Yubo Fan5. 1. Beijing Key Laboratory of Rehabilitation Technical Aids for Old-Age Disability, Key Laboratory of Human Motion Analysis and Rehabilitation Technology of the Ministry of Civil Affairs, National Research Center for Rehabilitation Technical Aids, 100176 Beijing, PR China. 2. Key Laboratory for Biomechanics and Mechanobiology of Ministry of Education, School of Biological Science and Medical Engineering, Beihang University, 100191 Beijing, PR China. 3. Wangjing Hospital, China Academy of Chinese Medical Sciences, Beijing, PR China. 4. Wangjing Hospital, China Academy of Chinese Medical Sciences, Beijing, PR China. Electronic address: wjm5734@263.net. 5. Beijing Key Laboratory of Rehabilitation Technical Aids for Old-Age Disability, Key Laboratory of Human Motion Analysis and Rehabilitation Technology of the Ministry of Civil Affairs, National Research Center for Rehabilitation Technical Aids, 100176 Beijing, PR China; Key Laboratory for Biomechanics and Mechanobiology of Ministry of Education, School of Biological Science and Medical Engineering, Beihang University, 100191 Beijing, PR China. Electronic address: yubofan@buaa.edu.cn.
Abstract
BACKGROUND: Deformity of the first ray in hallux valgus patient has been deemed to mainly contribute to instability of the metatarsophalangeal joint. However, it is not clear whether the fixation of the distal osteotomy fragment and transposition of the sesamoid represent the best method for hallux valgus treatment. The aim of this study was to examine how postoperative hallux valgus osteotomy affects the stability of the first ray. METHODS: To accurately investigate the biomechanical behavior of the first ray in pre-/postoperative hallux valgus patients, we described the relative displacement and stress distribution of the first metatarsal bone and sesamoid by imageology, test measurement and foot finite element model. FINDINGS: Compared with the preoperative hallux valgus, the plantar pressure decreased by 47.8% and was redistributed on second metatarsal region. The peak stress and relative displacement of the distal osteotomy fragment increased by +55.7% and -59.9%, respectively. The movement of this component shifted toward the positive sagittal axis direction. In addition, the relative displacement of sesamoid decreased by 87.4% (0.18 mm) in vertical axis direction and the stress was also redistributed on medial and lateral region. Moreover, the strain of the medial main ligament was more favorable to reconstruct function of the first ray. INTERPRETATION: The findings showed that the osteotomy method was helpful for stability of the first ray. This would provide the stability suggestions for postoperative hallux valgus fixation and guide further rehabilitation.
BACKGROUND: Deformity of the first ray in hallux valguspatient has been deemed to mainly contribute to instability of the metatarsophalangeal joint. However, it is not clear whether the fixation of the distal osteotomy fragment and transposition of the sesamoid represent the best method for hallux valgus treatment. The aim of this study was to examine how postoperative hallux valgus osteotomy affects the stability of the first ray. METHODS: To accurately investigate the biomechanical behavior of the first ray in pre-/postoperative hallux valguspatients, we described the relative displacement and stress distribution of the first metatarsal bone and sesamoid by imageology, test measurement and foot finite element model. FINDINGS: Compared with the preoperative hallux valgus, the plantar pressure decreased by 47.8% and was redistributed on second metatarsal region. The peak stress and relative displacement of the distal osteotomy fragment increased by +55.7% and -59.9%, respectively. The movement of this component shifted toward the positive sagittal axis direction. In addition, the relative displacement of sesamoid decreased by 87.4% (0.18 mm) in vertical axis direction and the stress was also redistributed on medial and lateral region. Moreover, the strain of the medial main ligament was more favorable to reconstruct function of the first ray. INTERPRETATION: The findings showed that the osteotomy method was helpful for stability of the first ray. This would provide the stability suggestions for postoperative hallux valgus fixation and guide further rehabilitation.