Effects of extracorporeal shock wave therapy and radial pressure wave therapy on elasticity and microstructure of equine cortical bone

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.

Effects of radial shock waves therapy on osteoblasts activities

Radial shock waves therapy (RSWT) differs from extracorporeal shock waves therapy (ESWT) in that it produces a non-focused wave that is dissipated radially at the skin. Few studies have yet explored the effects of RSWT on bone tissue. Osteoblasts in culture flasks were studied by polymerase chain reaction after treatment with RSW (500 impulses, 0.05 mJ/mm(2)). An inhibited osteoblastogenesis was observed, with a statistically significant reduction in type 1 collagen, osterix, bone sialoprotein and receptor activator NF kappa ligand expression at 24 and 48 h, of osteocalcin at 24, 48 and 72 h, and osteopontin at 48 and 72 h. These findings show that RSWT is not indicated for treatment of delayed fracture union, pseudoarthrosis, and complex regional pain syndrome. The observed reduction in the receptor activator of nuclear factor-kB ligand/osteoprotegerin ratio suggests that it has an inhibiting effect on osteoclastogenesis, which could make it a useful tool for applications in proliferative diseases.

Shock waves in the treatment of post-traumatic myositis ossificans

Myositis ossificans (MO) is a fairly common evolution in sports activity and can be due to direct trauma or to repeated micro-injuries. The traditional therapeutic approach relies on a variety of treatments, such as physical therapy but evidence of their proven clinical efficacy is lacking. The latest therapeutic option is surgical removal but this is a demolitive procedure and is frequently associated with a significant loss of functional integrity. There are few articles in literature about the treatment of post-traumatic MO, and none on extracorporeal shock wave therapy (ESWT). We illustrate a case series of 24 sportsmen treated with three sessions of electro-hydraulic shockwave therapy and an associated rehabilitation program. Only a partial reduction of the ossification was observed in the X-ray images but all the patients showed signs of functional improvement immediately after therapy. Two months after the therapy, a normal range of motion and no signs of weakness were observed. Three months after treatment, 87.5% of patients resumed regular sports activities.

The effects of radial shock waves on the metabolism of equine cartilage explantsin vitro

AIM

To investigate, in vitro, the effects of radial shock waves on the release of nitric oxide (NO) and synthesis of prostaglandin E2 (PGE2) and glycosaminoglycan (GAG), and liberation of GAG, from equine articular cartilage explants.

METHODS

Equine cartilage from normal metacarpophalangeal and metatarsophalangeal joints was exposed to radial shock waves at various impulse doses and then maintained as explants in culture for 48 h. Shock waves were delivered at 1,876 Torr pressure and a frequency of 10 Hz. Treatment groups consisted of a negative control group, or application of 500, 2,000, or 4,000 impulses by use of either a convex handpiece (Group A) or concave handpiece (Group B). Synthesis of GAG was measured using incorporation of 35S-labelled sodium sulphate. Additionally, the synthesis of NO and PGE2, and content of GAG of the explants and media were determined.

RESULTS

No significant effects (p>0.05) of radial shock-wave treatment were evident on the synthesis of NO or PGE2, or release of GAG by cartilage explants. However, radial shock waves decreased synthesis of GAG measured 48 h after exposure for all treatment groups other than the 500-impulse Group-A explants (p<0.05).

CONCLUSIONS

Radial shock waves impact the metabolism of GAG in chondrocytes in equine articular cartilage. Further studies will be required to fully investigate the impact of this effect on the health of joints, and to elucidate the clinical impact.

Assessment of scintigraphic and thermographic changes after focused extracorporeal shock wave therapy on the origin of the suspensory ligament and the fourth metatarsal bone in horses without lameness

OBJECTIVE

To monitor the effect of focused extra-corporeal shock wave therapy (ESWT) on bone and bone-tendon junction of horses without lameness by use of nuclear scintigraphy and thermography.

ANIMALS

6 warmblood horses without lameness.

PROCEDURE

The origin of the suspensory ligament at the metacarpus (OSL-MC) and the fourth metatarsal bone were treated at 2 time points (days 0 and 16) with 2,000 shocks applied by a focused ESWT device at an energy flux density of 0.15 mJ/mm2. One forelimb and 1 hind limb were treated, and the contralateral limbs served as controls. To document the effect of focused ESWT, nuclear scintigraphy was performed on days -1, 3, 16 (before second ESWT), and 19. Thermography was performed on days -1, 0 (1 hour after first ESWT), 1, 3, 8, 16 (twice; before and 1 hour after second ESWT), and 19. On days 3, 16 (first scans), and 19, thermography was performed before scintigraphy.

RESULTS

Scintigraphically, significant variations in radiopharmaceutical activity at the OSL-MC were detected in treatment and control limbs. No significant differences, however, in mean temperature or radiopharmaceutical activity could be detected by use of thermography or nuclear scintigraphy, respectively, between the treatment and control limbs at any time point in response to ESWT.

CONCLUSIONS AND CLINICAL RELEVANCE

After 2 treatments of focused ESWT, no physiologic effect on the studied structures could be demonstrated by use of nuclear scintigraphy or thermography. Results of this study indicate that at currently used ESWT settings, no damage to the bone or bone-tendon junction should occur.

Histomorphologic evaluation of extracorporeal shock wave therapy of the fourth metatarsal bone and the origin of the suspensory ligament in horses without lameness

OBJECTIVE

To determine via histologic examination and scintigraphy the effect of focused extracorporeal shock wave therapy (ESWT) on normal bone and the bone-ligament interface in horses.

ANIMALS

6 horses without lameness.

PROCEDURE

Origins of the suspensory ligament at the metacarpus (35-mm probe depth) and fourth metatarsal bone (5-mm probe depth) were treated twice (days 0 and 16) with 2,000 shocks (energy flux density, 0.15 mJ/mm2). One forelimb and 1 hind limb were randomly treated, and the contralateral limbs served as nontreated controls. Bone scans were performed on days -1 (before ESWT), 3, 16, and 19. Histomorphologic studies of control and treated tissues were performed on day 30.

RESULTS

ESWT significantly increased the number of osteoblasts but caused no damage to associated soft tissue structures and did not induce cortical microfractures. A significant correlation between osteoblast numbers and radiopharmaceutical uptake was noticed on lateral views of the hind limb on days 3 and 16 and on caudal views of the forelimb on day 3.

CONCLUSIONS AND CLINICAL RELEVANCE

Results suggested that ESWT has the potential to increase osteoblast numbers in horses. The correlation between increased osteoblast numbers and radio-pharmaceutical uptake 3 days and 16 days after the first ESWT suggested that stimulation of osteogenesis occurred soon after ESWT. No damage to bone or the bone-ligament interface should occur at the settings used in this study, and ESWT can therefore be administered safely in horses.

Extracorporeal Shock Wave Therapy for Treatment of Osteoarthritis in the Horse: Clinical Applications

Veterinarians have begun using extracorporeal shock wave therapy (ESWT) for treatment of osteoarthritis (OA) in horses, although relatively little information has been published about its efficacy or mechanism of action. As a clinician, it can be difficult to know if and when ESWT should be recommended. Case studies in which ESWT is used to treat advanced OA in horses are discussed. ESWTseems to be a valuable adjunct for management of equine OA. It is the purpose of this article to discuss indications and techniques as well as to share clinical experiences using ESWT in the treatment of OA in the horse.

Effects of radial shock waves on membrane permeability and viability of chondrocytes and structure of articular cartilage in equine cartilage explants

OBJECTIVE

To investigate in vitro effects of radial shock waves on membrane permeability, viability, and structure of chondrocytes and articular cartilage.

SAMPLE POPULATION

Cartilage explants obtained from the third metacarpal and metatarsal bones of 6 horses.

PROCEDURE

Equine cartilage was subjected to radial shock waves and then maintained as explants in culture for 48 hours. Treatment groups consisted of a negative control group; application of 500, 2,000, and 4,000 impulses by use of a convex handpiece (group A); and application of 500, 2,000, and 4,000 impulses by use of a concave handpiece (group B). Effects on explant structure were evaluated by use of environmental scanning electron microscopy (ESEM). Membrane permeability was determined by release of lactate dehydrogenase (LDH). Chondrocyte viability was assessed by use of vital cell staining. Comparisons of LDH activity and nonviable cell percentages were performed by ANOVA.

RESULTS

Cell membrane permeability increased significantly after application of 2,000 and 4,000 impulses in groups A and B. A significant decrease in cell viability was observed for application of 4,000 impulses in explants of group A. There was no detectable damage to integrity of cartilage explants observed in any treatment group by use of ESEM.

CONCLUSIONS AND CLINICAL RELEVANCE

Radial shock waves do not appear to structurally damage articular cartilage but do impact chondrocyte viability and membrane permeability. Caution should be exercised when extremely high periarticular pulse doses are used until additional studies can determine the long-term outcome of these effects and appropriate periarticular treatment regimens can be validated.

Evaluation of analgesia resulting from extracorporeal shock wave therapy and radial pressure wave therapy in the limbs of horses and sheep

OBJECTIVE

To identify the duration and potential mechanisms of analgesia following extracorporeal shock wave therapy (ESWT) and radial pressure wave therapy (RPWT) in limbs of horses and sheep.

ANIMALS

6 horses and 30 sheep.

PROCEDURE

An electrical stimulus was used to identify the nociceptive threshold for each horse daily for 3 days before treatment (baseline) with ESWT or RPWT, 8 hours after treatment, and at 24-hour intervals for 7 days after treatment. Testing was conducted for the treatment field (midmetacarpus or midmetatarsus) and nerve field (medial and lateral forelimb heel bulbs) distal to a treatment site that included the nerve on the abaxial surface of the proximal sesamoid bone. All 4 limbs of 30 sheep were treated with ESWT, RPWT, or a sham treatment. Two sheep were euthanatized daily and tissue harvested for histologic evaluation of nerves, and concentrations of substance P and calcitonin gene-related peptide were measured in the skin and periosteum.

RESULTS

Values did not differ significantly between baseline and after treatment for the treatment field or nerve field sensation. There was a large difference in the slope when data for horses were plotted for the first 3 days after treatment, compared with the slope for days 4 to 7 after treatment. No differences were found in neuropeptide concentrations after treatment of the sheep, but there was an inflammatory response in the treated nerves.

CONCLUSIONS AND CLINICAL RELEVANCE

A small cutaneous analgesic effect may exist at the treatment site for approximately 3 days after ESWT or RPWT in horses.