scholarly journals Influence of high-frequency cyclical stimulation on the bone fracture-healing process: mathematical and experimental models

Author(s):  
María José Gómez-Benito ◽  
Libardo Andrés González-Torres ◽  
Esther Reina-Romo ◽  
Jorge Grasa ◽  
Belén Seral ◽  
...  

Mechanical stimulation affects the evolution of healthy and fractured bone. However, the effect of applying cyclical mechanical stimuli on bone healing has not yet been fully clarified. The aim of the present study was to determine the influence of a high-frequency and low-magnitude cyclical displacement of the fractured fragments on the bone-healing process. This subject is studied experimentally and computationally for a sheep long bone. On the one hand, the mathematical computational study indicates that mechanical stimulation at high frequencies can stimulate and accelerate the process of chondrogenesis and endochondral ossification and consequently the bony union of the fracture. This is probably achieved by the interstitial fluid flow, which can move nutrients and waste from one place to another in the callus. This movement of fluid modifies the mechanical stimulus on the cells attached to the extracellular matrix. On the other hand, the experimental study was carried out using two sheep groups. In the first group, static fixators were implanted, while, in the second one, identical devices were used, but with an additional vibrator. This vibrator allowed a cyclic displacement with low magnitude and high frequency (LMHF) to be applied to the fractured zone every day; the frequency of stimulation was chosen from mechano-biological model predictions. Analysing the results obtained for the control and stimulated groups, we observed improvements in the bone-healing process in the stimulated group. Therefore, in this study, we show the potential of computer mechano-biological models to guide and define better mechanical conditions for experiments in order to improve bone fracture healing. In fact, both experimental and computational studies indicated improvements in the healing process in the LMHF mechanically stimulated fractures. In both studies, these improvements could be associated with the promotion of endochondral ossification and an increase in the rate of cell proliferation and tissue synthesis.

Author(s):  
Satoshi Kimura ◽  
Keisuke Oe ◽  
Yohei Kumabe ◽  
Tomoaki Fukui ◽  
Takahiro Niikura ◽  
...  

Biomedicines ◽  
2021 ◽  
Vol 9 (6) ◽  
pp. 691
Author(s):  
Jan Barcik ◽  
Devakara R. Epari

The impact of the local mechanical environment in the fracture gap on the bone healing process has been extensively investigated. Whilst it is widely accepted that mechanical stimulation is integral to callus formation and secondary bone healing, treatment strategies that aim to harness that potential are rare. In fact, the current clinical practice with an initially partial or non-weight-bearing approach appears to contradict the findings from animal experiments that early mechanical stimulation is critical. Therefore, we posed the question as to whether optimizing the mechanical environment over the course of healing can deliver a clinically significant reduction in fracture healing time. In reviewing the evidence from pre-clinical studies that investigate the influence of mechanics on bone healing, we formulate a hypothesis for the stimulation protocol which has the potential to shorten healing time. The protocol involves confining stimulation predominantly to the proliferative phase of healing and including adequate rest periods between applications of stimulation.


2019 ◽  
Vol 19 (05) ◽  
pp. 1950021
Author(s):  
JALIL NOURISA ◽  
GHOLAMREZA ROUHI

To date, several studies have implied the importance of early stage mechanical stability in the bone fracture healing process. This study aimed at finding a correlation between the predicted different tissue phenotypes in the early stages of healing and the ultimate healing outcome. For this purpose, the process of fracture healing was numerically simulated employing an axisymmetric bi-phasic finite element (FE) model for three initial gap sizes of 1, 3 and 6[Formula: see text]mm and four initial interfragmentary strains (IFS) of 7%, 11%, 15% and 19%. The model was validated with experimental and other numerical studies from the literature. Results of this study showed that the amount of cartilage and fibrous tissue observed in the early stage after fracture can be used to qualitatively assess the outcome of complete bone healing process. Greater amount of cartilage in early stage of healing process yielded faster callus maturation, and delayed maturation of callus was predicted in the case of high fibrous tissue production. Results of this study can be used to provide an estimation of the performance of different fixation systems by considering the amounts of cartilage and fibrous tissues observed in the early stage of healing.


2020 ◽  
Vol 21 (1) ◽  
Author(s):  
K. Jäckle ◽  
J. P. Kolb ◽  
A. F. Schilling ◽  
C. Schlickewei ◽  
M. Amling ◽  
...  

Abstract Background Osteoporosis affects elderly patients of both sexes. It is characterized by an increased fracture risk due to defective remodeling of the bone microarchitecture. It affects in particular postmenopausal women due to their decreased levels of estrogen. Preclinical studies with animals demonstrated that loss of estrogen had a negative effect on bone healing and that increasing the estrogen level led to a better bone healing. We asked whether increasing the estrogen level in menopausal patients has a beneficial effect on bone mineral density (BMD) during callus formation after a bone fracture. Methods To investigate whether estrogen has a beneficial effect on callus BMD of postmenopausal patients, we performed a prospective double-blinded randomized study with 76 patients suffering from distal radius fractures. A total of 31 patients (71.13 years ±11.99) were treated with estrogen and 45 patients (75.62 years ±10.47) served as untreated controls. Calculated bone density as well as cortical bone density were determined by peripheral quantitative computed tomography (pQCT) prior to and 6 weeks after the surgery. Comparative measurements were performed at the fractured site and at the corresponding position of the non-fractured arm. Results We found that unlike with preclinical models, bone fracture healing of human patients was not improved in response to estrogen treatment. Furthermore, we observed no dependence between age-dependent bone tissue loss and constant callus formation in the patients. Conclusions Transdermally applied estrogen to postmenopausal women, which results in estrogen levels similar to the systemic level of premenopausal women, has no significant beneficial effect on callus BMD as measured by pQCT, as recently shown in preclinical animal models. Trial registration Low dose estrogen has no significant effect on bone fracture healing measured by pQCT in postmenopausal women, DRKS00019858. Registered 25th November 2019 - Retrospectively registered. Trial registration number DRKS00019858.


Author(s):  
L. Geris ◽  
R. Schugart ◽  
H. Van Oosterwyck

Wound and bone fracture healing are natural repair processes initiated by trauma. Over the last decade, many mathematical models have been established to investigate the healing processes in silico , in addition to ongoing experimental work. In recent days, the focus of the mathematical models has shifted from simulation of the healing process towards simulation of the impaired healing process and the in silico design of treatment strategies. This review describes the most important causes of failure of the wound and bone fracture healing processes and the experimental models and methods used to investigate and treat these impaired healing cases. Furthermore, the mathematical models that are described address these impaired healing cases and investigate various therapeutic scenarios in silico . Examples are provided to illustrate the potential of these in silico experiments. Finally, limitations of the models and the need for and ability of these models to capture patient specificity and variability are discussed.


2018 ◽  
Vol 40 ◽  
pp. 56
Author(s):  
Libardo Andrés González Torres ◽  
Stephany De Camilo e Alonso ◽  
Agnes Batista Meireles

Bone fractures has high incidence and despite its relevance and frequency, some bone healing process features are still unknown. In this work, it is computationally investigated the influence of low amplitude and high frequency mechanical stimulation on cell differentiation during bone healing, using a cell differentiation theory that relates two mechanical variables (strain and flow velocity of interstitial fluid) with the cell fate. For this purpose, a finite element model was developed to study three hypothetical situations, to determine in which proportion external stimulation influences bone healing. Firstly, the mechanical stimulus was computed as 20% of external mechanical stimulus and 80% of the stimulus during gait. Secondly, it was considered 50% external mechanical stimulus and 50% gait stimulus. Finally, it was considered a proportion of 80% external mechanical stimulus and 20% gait stimulus. The results indicated that hypothesis considering high proportions of external stimulation results in unreal delayed healing process and the first hypothetical situation proved to be that which best represents the real process. From the results obtained, it was concluded that external mechanical stimulation does not affected directly cell differentiation during bone healing. Thus, other processes such as flow of oxygen, nutrients or wastes must be considered.


2005 ◽  
Vol 58 (9-10) ◽  
pp. 507-512
Author(s):  
Djordje Gajdobranski ◽  
Ivan Micic ◽  
Milorad Mitkovic ◽  
Desimir Mladenovic ◽  
Miroslav Milankov

Introduction Establishing continuity of long bones in cases of impaired bone healing and pseudo-arthrosis is one of the most complex problems in orthopedics. Impaired bone healing The problem of impaired fracture healing is not new. As in other areas of human life, the roots of modern treatment of impaired bone healing lie in ancient medicine. A relatively high percentage of impaired bone healing, as well as unsatisfactory results of standard therapies of impaired bone healing and pseudoarthrosis demonstrate the actuality of this problem. This paper represents an attempt to pay respect to some of those who have dedicated their work to this problem in orthopedic surgery, and it is a historical review on impaired bone fracture healing. At the same time it should be an additional stimulus and challenge for orthopedic surgeons to further study impaired bone fracture healing, improve the existing and find new methods for their adequate treatment. Conclusion The authors are certain that the number of researchers throughout the world who have contributed to treatment modalities of impaired bone healing, is much higher, but not all are mentioned in this paper. However, it does not lessen their contributions to orthopedics.


2020 ◽  
Vol 10 (2) ◽  
Author(s):  
Al-Habib MF ◽  
Salman MO ◽  
Faleh FW ◽  
Al-Ani IM

Objective: To study the effect of both laser and ultrasound radiation on bone fracture healing process. Materials and Methods: Nd:YAG laser (1064 nm wavelength, 135 mW power, 16 joules energy) and ultrasound (1 MHz frequency, 50 mW/cm2 power intensity) were used in this work. Fifteen mature, male, albino rats, were divided into three groups and subjected to a partial fracture on the lateral aspect of femur by a sharp blade. The fi rst group of these animals served as control group. The second group was illuminated by the Nd:YAG laser for two minutes; the fi rst dose was given immediately after surgical fracture induction; the other doses were given on days two, three, six and then one dose weekly for the next three weeks while the third group were treated by the addition of the CW ultrasound perpendicular to the laser treatment in the second group. Results: The present study showed that ultrasound increases the penetration of laser power through the tissue. The histological assessments at day 28 after the fracture of fi rst group showed incomplete healing of the bone with disfi guration and disarrangement of Haversian system and the periosteum was not yet well developed. Treatment with laser showed irregularity and lack of Haversian system formation in bone healing of the second group. The laser and ultrasound treated group (third group) expressed a complete healing at the site of fracture with a complete layer of periosteum and a well arranged Haversian system. Conclusion: Combination of laser and ultrasound in therapy can enhance healing process of a fractured bone more than laser therapy alone, as ultrasound increases the depth of laser penetration in tissue.


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