Optimization of screw fixation in rat bone with extracorporeal shock waves

The Effects of the Exposure of Musculoskeletal Tissue to Extracorporeal Shock Waves

Extracorporeal shock wave therapy (ESWT) is a safe and effective treatment option for various pathologies of the musculoskeletal system. Many studies address the molecular and cellular mechanisms of action of ESWT. However, to date, no uniform concept could be established on this matter. In the present study, we perform a systematic review of the effects of exposure of musculoskeletal tissue to extracorporeal shock waves (ESWs) reported in the literature. The key results are as follows: (i) compared to the effects of many other forms of therapy, the clinical benefit of ESWT does not appear to be based on a single mechanism; (ii) different tissues respond to the same mechanical stimulus in different ways; (iii) just because a mechanism of action of ESWT is described in a study does not automatically mean that this mechanism is relevant to the observed clinical effect; (iv) focused ESWs and radial ESWs seem to act in a similar way; and (v) even the most sophisticated research into the effects of exposure of musculoskeletal tissue to ESWs cannot substitute clinical research in order to determine the optimum intensity, treatment frequency and localization of ESWT.

Extracorporeal shock wave therapy: an update

Extracorporeal shock wave therapy (ESWT) is a safe therapy and there are only a few side effects known (such as pain during ESWT and minor haematomata), but no severe complications are to be expected if it is performed as recommended.

Contraindications are severe coagulopathy for high-energy ESWT, and ESWT with focus on the foetus or embryo and focus on severe infection.

The effect mechanism of ESWT is still a component of diverse studies, but as far as we can summarize today, it is a similar process to a cascade triggered by mechano-transduction: mechanical energy causes changes in the cellular skeleton, which provokes a reaction of the cell core (for example release of mRNA) to influence diverse cell structures such as mitochondria, endoplasmic reticulum, intracellular vesicles, etc., so the enzymatic response leads to the improvement of the healing process.

The usage of ESWT should be taught, to improve the outcome. Courses should be organized by national societies, since the legal framework conditions are different from one country to another.

In this update the musculoskeletal indications are addressed (mainly bone and tendons): pseudoarthrosis, delayed fracture healing, bone marrow oedema and osteonecrosis in its early stages, insertional tendinopathies such as plantar fasciitis and Achilles tendon fasciitis, calcifying tendonitis of the rotator cuff, tennis elbow, and wound healing problems.

Cite this article: EFORT Open Rev 2020;5:584-592. DOI: 10.1302/2058-5241.5.190067

Focused high-energy extracorporeal shockwaves as supplemental treatment in a rabbit model of fracture-related infection

Focused high-energy extracorporeal shockwave therapy (fhESWT) is used to improve fracture healing in cases of nonunion. In addition, it has been shown to have direct antibacterial effects. We evaluated fhESWT as an adjunct to conventional treatment in a clinically relevant rabbit model of fracture-related infection (FRI). A humeral osteotomy in 31 rabbits was fixed with a seven-hole locking compression plate. FRI was established with a clinical Staphylococcus aureus isolate. After 2 weeks, a revision surgery was performed with debridement, irrigation, and implant retention. Rabbits then received: no further treatment (controls); shockwaves (4000 impulses with 23 kV at days 2 and 6 after revision); systemic antibiotics (rifampin and nafcillin); or the combination of antibiotics and shockwaves. Treatments were applied over 1 week. Blood cultures were taken before and after shockwave sessions. After another week without treatment, rabbits were euthanized and quantitative bacteriology was performed on implants and tissues to determine infection burden. Indicator organs (brain, heart, liver, lungs, kidneys, and spleen) were cultured to assess possible bacteremia. All the rabbits were infected at revision surgery as determined by the bacteriological culture of debrided materials. fhESWT in combination with antibiotic treatment lowered the bacterial burden 100-fold compared with antibiotic treatment alone in all samples (P = .38). This effect was most prevalent for the implant sample (P = .08). No significant effect was seen for fhESWT alone compared with untreated controls. No signs of bacteremia occurred in blood cultures and organs. fhESWT appears safe and could be a helpful adjunct to conventional treatment in certain difficult-to-treat FRIs.

Coupling between Osseointegration and Mechanotransduction to Maintain Foreign Body Equilibrium in the Long-Term: A Comprehensive Overview

The permanent interaction between bone tissue and the immune system shows us the complex biology of the tissue in which we insert oral implants. At the same time, new knowledge in relation to the interaction of materials and the host, reveals to us the true nature of osseointegration. So, to achieve clinical success or perhaps most importantly, to understand why we sometimes fail, the study of oral implantology should consider the following advice equally important: a correct clinical protocol, the study of the immunomodulatory capacity of the device and the osteoimmunobiology of the host. Although osseointegration may seem adequate from the clinical point of view, a deeper vision shows us that a Foreign Body Equilibrium could be susceptible to environmental conditions. This is why maintaining this cellular balance should become our therapeutic target and, more specifically, the understanding of the main cell involved, the macrophage. The advent of new information, the development of new implant surfaces and the introduction of new therapeutic proposals such as therapeutic mechanotransduction, will allow us to maintain a healthy host-implant relationship long-term.

Effect of unfocused extracorporeal shockwave therapy on bone mineral content of twelve distal forearms of postmenopausal women: a clinical pilot study

Extracorporeal shockwave therapy showed a pronounced effect on bone mass in previous animal studies. We showed in this pilot study that a single treatment with unfocused shockwave therapy in unselected patients does not show side effects. Although our study did not show any effect of shockwave on BMD, the limited sample size does not definitively exclude this and a study with 174 subjects per group would be needed to show an effect size of 0.3 with a power of 80%.

PURPOSE

Unfocused extracorporeal shockwave therapy might stimulate bone formation to reduce the fracture risk. In this study, we assessed the safety of unfocused extracorporeal shockwave therapy and its effects on bone mass.

METHODS

A clinical pilot study with twelve female patients free of bone disease undergoing elective surgery of the lower extremity or elective spinal surgery under general anesthesia received 3.000 electrohydraulic-generated unfocused extracorporeal shockwaves (energy flux density 0.3 mJ/mm²) to one distal forearm. The contralateral forearm served as a control. We examined the effect on bone mass with the use of repeated dual energy X-ray absorptiometry measurements and we measured patient discomfort around the therapy.

RESULTS

No difference in bone mineral content and density was measured 6 and 12 weeks after therapy. shockwave therapy occasionally caused transient erythema or mild hematoma, but no discomfort in daily life or (late) adverse events.

CONCLUSIONS

Unfocused extracorporeal shockwave therapy is a safe treatment, but no increase in bone mass on the forearm was found at 0.3 mJ/mm² energy flux density. In this study, we were not able to demonstrate that a single treatment with unfocused shockwave therapy in unselected patients had any effect in terms of bone mineral density (BMD) or bone mineral content (BMC). A power analysis indicated that 174 patients per group are required to show an effect size of 0.3 with a power of 80%.