Date Published: September 12, 2019
Publisher: Sociedade Brasileira para o Desenvolvimento da Pesquisa em Cirurgia
Author(s): Degong Mu, Jing Yu, Junhao Lin, Chen Li, Baohui Hao, Feng Gu, Chao Liu, Lei Tan, Dong Zhu, Xizheng Zhang.
To investigate the effect of intermittent vibration at different intervals on bone fracture healing and optimize the vibration interval.
Ninety sheep were randomized to receive no treatment (the control group), incision only (the sham control group), internal fixation with or without metatarsal fracture (the internal fixation group), and continuous vibration in addition to internal fixation of metatarsal fracture, or intermittent vibration at 1, 2, 3, 5, 7 and 17-day interval in addition to internal fixation of metatarsal fracture (the vibration group). Vibration was done at frequency F=35 Hz, acceleration a=0.25g, 15 min each time 2 weeks after bone fracture. Bone healing was evaluated by micro-CT scan, bone microstructure and mechanical compression of finite element simulation.
Intermittent vibration at 7-day interval significantly improved bone fracture healing grade. However, no significant changes on microstructure parameters and mechanical properties were observed among sheep receiving vibration at different intervals.
Clinical healing effects should be the top concern. Quantitative analyses of bone microstructure and of finite element mechanics on the process of fracture healing need to be further investigated.
Fracture healing is a complex process that involves the coordination of a sequence of biological events, and is delayed in approximately 5-10% of bone fractures due to various causes1,2. Efforts have been made to shorten healing time, and improve healing quality. During t bone development and growth, the size, shape and intensity of the bone largely depend on mechanical stimulation, the responses to which could promote bone modeling and remodeling3.
The study protocol was approved by the local ethics committee at the authors’ affiliated institutions. All experiment procedures were carried out in accordance with the Regulatory Guideline on the Use of Experimental Animals (China, 2011). Ninety healthy 1-year-old shorttailed Han sheep (Jilin Animal Experimental Center, Jilin, China) were housed in the same environment including lighting, ventilation, humidity, and temperature, with ad libitum access to sunshine, water and food. The sheepcotes were regularly cleaned up to ensure a good feeding environment.
Based on our results, to compare with natural fracture healing, we first found that low load mechanical vibration can improve fracture healing. Intermittent vibration effect on healing is better than continuous vibration effect, the best effect of 71.4% of recovery with grade 3 was observed in sheep receiving intermittent vibration at 7-day interval; on the contrary, only 14.3% of recovery with grade 3 was found in sheep undergoing natural healing without vibration treatment).
Clinical healing effects should be the top concern. The quantitative analyses of bone microstructure and of finite element mechanics on the process of fracture healing need to be further investigated.