Therapeutic ultrasound enhances medial collateral ligament repair in rats

The therapeutic effects of low-intensity pulsed ultrasound in musculoskeletal soft tissue injuries: Focusing on the molecular mechanism

Musculoskeletal soft tissue injuries are very common and usually occur during both sporting and everyday activities. The intervention of adjuvant therapies to promote tissue regeneration is of great importance to improving people's quality of life and extending their productive lives. Though many studies have focused on the positive results and effectiveness of the LIPUS on soft tissue, the molecular mechanisms standing behind LIPUS effects are much less explored and reported, especially the intracellular signaling pathways. We incorporated all research on LIPUS in soft tissue diseases since 2005 and summarized studies that uncovered the intracellular molecular mechanism. This review will also provide the latest evidence-based research progress in this field and suggest research directions for future experiments.

System and method for applying physiotherapeutic focused ultrasound

Despite many years of clinical use of ultrasound, the results of different reviews of controlled trials on the efficacy of ultrasound physical therapy for different musculoskeletal injuries continue to question its efficacy. However, "in vitro" experiments with well-controlled cell cultures and experiments with animal models show positive results. The question is whether the commercial systems used by physiotherapists can deliver the required ultrasonic dose to the exact location on the body. The object of this work is the design, realization and testing of a new concept of ultrasound system for Physiotherapy capable of focusing the ultrasound beam to apply the required ultrasonic energy dose at the point targeted by the physiotherapist. The system is designed for non-thermal effects Physiotherapy. The system consists of conceptually new piezocomposite arrays with a metallic delay line, multi-pulser electronics for emission focusing, parallel robots for mechanical steering and positioning of the array transducers, and linear and angular encoders to allow the physiotherapist to direct the focus to the target. The multi-pulser and parallel robot angulation are controlled by the computer, using a graphical interface software.

Low-Intensity Pulsed Ultrasound Augments Tendon, Ligament, and Bone-Soft Tissue Healing in Preclinical Animal Models: A Systematic Review

PURPOSE

To appraise the available animal and human studies investigating low-intensity pulsed ultrasound stimulation (LIPUS) on tendon, ligament, and bone-soft tissue (B-ST) junction healing.

METHODS

A systematic review of PUBMED, EMBASE, and the Cochrane Library was performed for animal and human studies investigating the effects of LIPUS on tendon, ligament, and B-ST junction healing. The systematic search was performed using the key term "low intensity pulsed ultrasound" and any of the following: "tendon," "ligament," "tendon-bone," and "bone-tendon." Inclusion criteria consisted of (1) randomized controlled trials assessing the effect of LIPUS on bone, tendon, and soft tissue in animals or humans and (2) English-language articles.

RESULTS

A total of 28 animal and 2 human studies met inclusion criteria. Animal studies utilized various models, including Achilles and patellar tendon transections, medial collateral ligament transections, and surgical repair of patellar tendon, rotator cuff tendon, and anterior cruciate ligament, to evaluate the effects of LIPUS. Animal studies demonstrated significantly improved collagen content and organization, bone formation, fibrocartilage remodeling, and mechanical strength with LIPUS treatment compared with controls. In human trials, LIPUS treatment of chronic tendinopathies did not improve clinical outcomes.

CONCLUSIONS

In acute injury animal models, LIPUS augmented healing of acute tendon, ligament, and B-ST junction injuries through increased collagen content and organization; increased anti-inflammatory cellular signaling; and increased angiogenesis. However, in 2 human studies investigating chronic tendinopathy, LIPUS did not lead to superior outcomes compared with controls.

CLINICAL RELEVANCE

Animal models suggest that LIPUS may be a promising noninvasive treatment modality for accelerating patient recovery after acute tendon and ligament injuries, as well as after surgical repair of B-ST junction injuries, but this has not been demonstrated in human studies. Randomized clinical trials evaluating LIPUS for acute tendon and ligament injuries are warranted.

Comparing therapeutic ultrasound with microamperage stimulation therapy for improving the strength of Achilles tendon repair

In exploring the effects of therapeutic ultrasound (US) and microamperage stimulation (MAS) on the biomechanical performance of repairing Achilles tendon in rats, 35 Sprague-Dawley rats receiving surgically induced injury to their right medial Achilles tendon were studied. The rats were divided into four groups of low-dose US (group 1, n = 10), high-dose US (group 2, n = 11), MAS (group 3, n = 7), and control (group 4, n = 7). The treatment started on day 6 after injury. Groups 1 and 2 received 4 min of daily US treatment at 1.0 and 2.0 W/cm(2), respectively. Group 3 received 30 min of daily transcutaneous MAS treatment. Group 4 received 30 min of daily sham MAS treatment. On day 31, the Achilles tendons were mechanically tested. Data on the right side were normalized to the left side and analyzed with MANOVA with α = 0.05. Results of MANOVA was significant and post hoc tests revealed that the normalized strength of groups 1, 2, and 3 were higher than that of group 4 (p = 0.003) but no significant difference was found among the treatment groups. The ANOVA result of the normalized load relaxation and stiffness was p = 0.06 and p = 0.07, respectively. These findings suggested that both low/high doses of US and MAS therapies could improve the strength of Achilles tendon but in view of its short treatment time, US is considered to be more efficient than MAS for improving the strength of the repairing tendons.

Análise nanoestrutural da ação do ultra-som terapêutico sobre o processo de regeneração do tendão de ratos

O ultra-som terapêutico pulsado (USTP) é uma das modalidades terapêuticas utilizadas para promover a aceleração do reparo tendíneo. Este estudo avaliou a microestrutura do tendão calcâneo sob o efeito do USTP em duas intensidades diferentes. Foram utilizados 24 ratos Wistar machos, divididos em quatro grupos, submetidos à tenotomia radical transversal do tendão calcâneo direito, sem posterior tenorrafia. Os animais do grupo controle (GC) não receberam tratamento; o grupo 1 (G1) foi submetido ao USTP de 1 MHz a 20%, com área de radiação efetiva de 1,0 cm² e intensidade média instantânea de 0,3 W/cm²; o grupo 2 (G2) recebeu USTP nos mesmos parãmetros, mas com intensidade de 1,5 W/cm²; no grupo 3 (G3), placebo, foi aplicado tratamento simulado (ultra-som desligado). Nos três grupos, o tratamento consistiu em uma sessão diária de 5 minutos, por 10 dias. No 11º dia pós-operatório os tendões foram removidos para análise qualitativa e quantitativa, por meio de microscopia de luz polarizada (MLP), de luz (ML) e de força atômica (MFA). As análises qualitativas de MLP e MFA foram coincidentes, mostrando melhor organização, agregação e orientação das fibras de colágeno no grupo G1. A análise quantitativa apresentou contagens médias de 400,7 fibroblastos e 2,22 capilares sangüíneos por campo de análise, não se encontrando diferença significativa entre os grupos (p>0,05). Conclui-se que o processo de regeneração tendínea em ratos pode ser beneficiado pelo tratamento com USTP em baixa intensidade.

Effect of transosseous application of low-intensity ultrasound at the tendon graft-bone interface healing: gene expression and histological analysis in rabbits

The present study investigates the effect of transosseous low-intensity pulsed ultrasound (LiUS) on the healing at tendon graft-bone interface, in molecular and histological level. The anterior cruciate ligament (ACL) in both knees of 52 New Zealand White rabbits was excised and replaced with the long digital extensor. A custom-made ultrasound transducer was implanted onto the medial tibial condyle, adjacent to the surface of the bone tunnel at both knees of the rabbits. The LiUS-treated right knees received 200-mus bursts of 1 MHz sine waves at a pulse repetition rate of 1 kHz and with 30 mW/cm(2) spatial-average temporal-average intensity for 20 min daily (study group), while the left knee received no LiUS (control group). Thirty-six rabbits were used to perform semiquantitative reverse transcription-polymerase chain reaction (RT-PCR) analysis from both study and control groups for transforming growth factor-beta1 (TGF-beta1), biglycan and collagen I. RT-PCR products showed statistically significant upregulation of biglycan and collagen I gene expression in the study group, while TGF-beta1 gene expression exhibited a bimodal profile. Histological examination performed in 16 rabbits from both groups supported the findings of the molecular analysis, indicating a faster healing rate and a more efficient ligamentization process after ultrasound treatment. These findings suggest that transosseous application of LiUS enhances the healing rate of the tendon graft-bone interface, possibly by affecting the expression levels of genes significant for the tendon to bone healing process.

Ultrasound phonophoresis of panax notoginseng improves the strength of repairing ligament: a rat model

This study examined the phonophoretic effect of a therapeutic ultrasound coupled with a Panax notoginseng (PN) gel and compared it with a therapeutic ultrasound alone for medial collateral ligament repair in rats. Twenty mature male Sprague-Dawley rats receiving surgical transection to the left medial collateral ligament (MCL) were divided randomly into three groups: ultrasound (US, n = 7), ultrasound with PN coupling gel (PNUS, n = 7) and control (n = 6). The treatments started on day 3 after surgery for six days per week over a two-week period. The US group received 4 min of pulsed ultrasound (1 MHz) at the intensity of 0.5W/cm(2) with a normal ultrasonic coupling gel. The PNUS group received the same ultrasound treatment, but with a coupling gel that contained PN extract. The control group received a placebo ultrasound treatment similar to the other two groups. On day 17, the ligaments were mechanically tested for load-relaxation, stiffness and ultimate tensile strength (UTS). Values of the left side were normalized against that of the right side of each animal for analysis. Results revealed significantly higher normalized stiffness (p = 0.009) and UTS (p = 0.022) in the PNUS group than the other two groups, but insignificant difference in load-relaxation among all groups. This study reveals a positive ultrasonic phonophoretic effect of Panax notoginseng extract for improving the strength of ligament repair than ultrasound therapy alone.