Focused ultrasound as an alternative to dry needling for the treatment of tendinopathies: A murine model.

Tendinopathies account for 30% of 102 million annual musculoskeletal injuries occurring annually in the United States. Current treatments, like dry needling, induce microdamage to promote healing but produce mixed success rates. Previously, we showed focused ultrasound can noninvasively create microdamage while preserving mechanical properties in ex vivo murine tendons. This present study compared growth factor, histological, and mechanical effects after focused ultrasound or dry needling treatments in an in vivo murine tendon injury model. Partial Achilles tenotomy was performed in 26 rats. One-week postsurgery, tendons were treated with focused ultrasound (1.5 MHz, 1-ms pulses at 10 Hz for 106 s, p+ = 49 MPa, p- = 19 MPa) or dry needling (30 G needle, 5 fenestrations over 20 s) and survived for 1 additional week. Blood was collected immediately before and after treatment and before euthanasia; plasma was assayed for growth factors. Treated tendons and contralateral controls were harvested for histology or mechanical testing. No differences were found between treatments in release of insulin growth factor 1 and transforming growth factor beta; vascular endothelial growth factor A concentrations were too low for detection. Histologically, focused ultrasound and dry needling tendons displayed localized fibroblast infiltration without collagen proliferation with no detectable differences between treatments. Mechanically, stiffness and percent relaxation of dry needling tendons were lower than controls (p = 0.0041, p = 0.0441, respectively), whereas stiffness and percent relaxation of focused ultrasound tendons were not different from controls. These results suggest focused ultrasound should be studied further to determine how this modality can be leveraged as a therapy for tendinopathies.

Investigation of the effects of umbilical cord-derived mesenchymal stem cells and curcumin on Achilles tendon healing - can they act synergistically?

BACKGROUND: It is known that curcumin and umbilical cord-derived mesenchymal stem cells (UC-MSCs) positively affect experi-mental tendon injury healing. This study investigated individual effects and potential synergistic effects of using curcumin and UC-MSCs alone and together. METHODS: Eighty female Wistar albino rats were randomly divided into five groups: Control, curcumin, sesame oil, MSCs, and Curcumin+MSCs groups. In all rats, punch tendon defect was created in both right and left Achilles tendons. While no additional treatment was applied to the control group, curcumin, sesame oil used as a solvent for curcumin, MSCs, and MSCs and curcumin com-bination were applied locally to the injury site, respectively, in the other groups. Curcumin was solved in sesame oil before application. In each group, half of the animals were euthanized in the post-operative 2nd week while the other half were euthanized in the post-operative 4th week. The right Achilles was used for biomechanical testing, while the left Achilles was used for histological evaluation and immunohistochemical analysis of type I, Type III collagen, and tenomodulin. RESULTS: Histologically, significant improvement was observed in the curcumin, MSCs, and Curcumin+ MSCs groups compared to the control Group in the 2nd week. In the 2nd and 4th weeks, Type III collagen was significantly increased in the curcumin group com-pared to the control group. In week 4, tenomodulin increased significantly in the curcumin and MSCs groups compared to the control group. Tendon tensile strength increased significantly in MSCs and Curcumin+MSCs groups compared to the control group in the 4th week. No superiority was observed between the treatment groups regarding their positive effects on recovery. CONCLUSION: Locally used curcumin and UC-MSCs showed positive effects that were not superior to each other in the healing of injury caused by a punch in the Achilles tendons of rats. However, synergistic effects on healing were not observed when they were applied together.

Histological, Physiological and Biomechanical Effects of Low-Level Laser Therapy on Tendon Healing in Animals and Humans: A Systematic Review.

Low-level Laser Therapy (LLLT) was widely used in clinical practice for tendon disorders. However, the underlying mechanisms and effectiveness of LLLT in treating tendon injury remain unclear. Therefore, the present study was conducted aiming to summarize the evidence regarding the histological, physiological, and biomechanical effects of LLLT on tendon healing in animal and human models. Four databases were searched for relevant literature. Four independent reviewers screened abstracts and full-text articles, extracted relevant data, evaluated the risk of bias, and quantified the quality of evidence. Database searches yielded 1400 non-duplicated citations. Fifty-five studies were included (50 animal and five human studies). Animal studies revealed that LT had stimulating effects on collagen organization, collagen I and collagen II formation, matrix metalloproteinase (MMP)-8, transforming growth factor ß1, vascular endothelial growth factor, hydroxyproline, maximum load, maximum elongation before breaking, and tendon stiffness. However, LLLT had inhibitory effects on the number of inflammatory cells, histological scores, relative amount of collagen III, cyclooxygenase-2, prostaglandin E2 (PGE2), interleukin-6, tumor necrosis factor-α, MMP-1, and MMP-3. Although one human study found that LLLT reduced the concentration of PGE2 in peritendinous tissue of the Achilles tendon, other human studies revealed that the effects of LLLT on the physiology and biomechanics of human tendons remained uncertain. LLLT facilitates tendon healing through various histological, physiological, and biomechanical effects in animal models. Only post-LLLT anti-inflammatory effects were found in human studies.

A Comprehensive Evaluation of Minimally Invasive Achilles Tendon Reconstruction with Hamstring Graft Indicates Satisfactory Long-Term Outcomes.

Background and objectives: The Achilles tendon, the largest tendon in the body, is vulnerable to injury because of its limited blood supply and the combination of forces to which it is subjected. Given the relevance of the Achilles tendon in the proper function of the foot and ankle, the primary goal of the present study was to use a holistic approach for a comprehensive evaluation of Achilles tendon reconstruction results on multiple levels. Materials and Methods: The study was designed in the following way: 30 patients with partial or total Achilles tendon tears were subjected to the minimally invasive Achilles tendon reconstruction. Patients were then subjected to the clinical, functional and isokinetic tests 12 and 24 months after the treatment. The clinical evaluation included calf circumference measurements and subjective patient-reported tests: ATRS, EQ-5D-5L and VAS scales. The functional evaluation was based on three tests: the weight-bearing lunge test, the heel rise test and single leg hop. Isometric and isokinetic evaluation was performed using a Biodex 3 dynamometer. Results: The calf circumference of the operated limbs was significantly lower than the non-operated limb 12 months after the surgical procedure, however this improved at the second evaluation. All subjective outcomes improved significantly 24 months after the surgery. Significantly better results in the function of the operated limbs were also obtained 24 months after the surgery. However, most of the muscle strength parameters of the operated limbs were already comparable to non-operated ones 12 months after the surgery and were comparable between two evaluation times. Conclusions: The overall results of this extensive evaluation are highly satisfactory and patients returned to their normal physical activity. From a medical point of view, it is assumed that the healing process is completed 12 months after the surgery, however, importantly, our results indicate that we should consider the healing process and the rehabilitation process separately.

[Application of wide-awake local anesthesia no tourniquet technique in the treatment of acute Achilles tendon rupture].

Objective: To explore the value of wide-awake local anesthesia no tourniquet (WALANT) technique in the treatment of acute Achilles tendon rupture. Methods: In a prospective randomized controlled trial, 48 patients with acute Achilles tendon rupture who met the criteria between March 2020 and October 2020 were randomly divided into two groups according to 1∶1 distribution, with 24 cases in each group. The study group used WALANT technique and the control group used epidural anesthesia with tourniquet for channel-assisted minimally invasive repair (CAMIR). There was no significant difference between the two groups in gender, age, injured side, cause of injury, distance from broken end of Achilles tendon to calcaneal tubercle, and time from injury to hospitalization ( P>0.05). The operating room use time (from patients entering the operating room to leaving the operating room), intraoperative blood loss, hospital stay, and the highest pain score [using Numerical Rating Scale (NRS)] during operation and at 1 day after operation were recorded and compared between the two groups. The tourniquet adverse reactions in the control group were recorded. The functional recovery was evaluated by the scoring method of American Orthopedic Foot and Ankle Society (AOFAS) at 12 months after operation. Results: The operation was successfully completed in both groups. The operating room use time and hospital stay in the study group were significantly less than those in the control group ( P<0.05), but the difference in the intraoperative blood loss between the two groups was not significant ( t=0.429, P=0.670). There was no significant difference in the highest NRS score during operation between the two groups ( t=1.671, P=0.101); the highest NRS score in the study group at 1 day after operation was significantly lower than that in the control group ( t=-6.384, P<0.001). In the control group, 13 patients had different degrees of tourniquet adverse reactions, including tourniquet regional pain, local swelling, blisters, thigh numbness, and discomfort. The patients in both groups were followed up 12-18 months, with an average of 13.9 months. The motor function of all patients returned to normal at 12 months after operation. The difference in AOFAS scores between the two groups was not significant ( t=0.345, P=0.731). There was no complication such as sural nerve injury, local infection, and secondary rupture in both groups. Conclusion: The application of WALANT combined with CAMIR technique in the treatment of acute Achilles tendon rupture has good anesthetic and effectiveness, avoids the adverse reactions of tourniquet, and reasonably saves social medical resources.

Photobiomodulation therapy increases collagen II after tendon experimental injury.

A tendon is a mechanosensitive tissue that transmits muscle-derived forces to bones. Photobiomodulation (PBM), also known as low-level laser therapy (LLLT), has been used in therapeutic approaches in tendon lesions, but uncertainties regarding its mechanisms of action have prevented its widespread use. We investigated the response of PBM therapy in experimental lesions of the Achilles tendon in rats. Thirty adult male Wistar rats weighing 250 to 300 g were surgically submitted to bilateral partial transverse section of the Achilles tendon. The right tendon was treated with PBM, whereas the left tendon served as a control. On the third postoperative day, the rats were divided into three experimental groups consisting of ten rats each, which were treated with PBM (Konf, Aculas - HB 750), 780 nm and 80 mW for 20 seconds, three times/week for 7, 14 and 28 days. The rats were sacrificed at the end of the therapeutic time period. The Sca-1 was examined by immunohistochemistry and histomorphometry, and COLA1, COLA2 and COLA3 gene expression was examined by qRT-PCR. COLA2 gene expression was higher in PBM treated tendons than in the control group. The histomorphometric analysis coincided with increased number of mesenchymal cells, characterized by Sca-1 expression in the lesion region (p<0.001). PBM effectively interferes in tendon tissue repair after injury by stimulating mesenchymal cell proliferation and the synthesis of collagen type II, which is suggested to provide structural support to the interstitial tissues during the healing process of the Achilles tendon. Further studies are needed to confirm the role of PBM in tendon healing.

Rehabilitation regimen for non-surgical treatment of Achilles tendon rupture: A systematic review and meta-analysis of randomised controlled trials.

OBJECTIVES: To compare re-rupture rate, functional and quality-of-life outcomes, return to sports and work, complications, and resource use in patients treated non-surgically with different rehabilitation regimens for Achilles tendon rupture. DESIGN: Systematic review and meta-analysis. METHODS: We performed a systematic literature search in PubMed, Embase, Scopus and the Cochrane Library through May 2020 to identify randomized controlled trials (RCTs) that included patients treated non-surgically for Achilles tendon rupture. All analyses were stratified according to rehabilitation protocols. RESULTS: Eight RCTs with a total of 978 patients were included. There was no significant difference about re-rupture rate (P=0.38), return to sports (P=0.85) and work (P=0.33), functional outcome (P=0.34), quality of life (P=0.50), and complication rate (P=0.29) between early weight bearing with functional ankle motion and traditional ankle immobilisation with non-weight bearing. Similarly, no significant difference in re-rupture rate (P=0.88), return to sports (P=0.45) and work (P=0.20), functional outcome (P=0.26), and complication rate (P=0.49) was seen between ankle immobilisation with non-weight bearing and early weight bearing without functional ankle motion. CONCLUSIONS: Traditional ankle immobilisation with non-weight bearing was not found to be superior to early weight bearing with or without functional ankle motion for patients treated non-surgically for Achilles tendon rupture. Clinicians may consider early weight bearing in functional brace as a safe and cost-effective alternative to non-weight bearing with plaster casting.

Comparison of the Effects of Pulsed Electromagnetic Field and Extracorporeal Shockwave Therapy in a Rabbit Model of Experimentally Induced Achilles Tendon Injury.

Achilles tendon injuries are a common cause of complications including adhesions and tendon degeneration. As a result of these complications, the biomechanical properties are lost. Extracorporeal shockwave therapy (ESWT) and pulsed electromagnetic field (PEMF) recover the injured tendon structure; however, detailed studies of changes in tendon biomechanical properties are limited. We hypothesized that PEMF application would improve Achilles tendon biomechanical properties similar to ESWT. The curative effects of a PEMF 4-week application (15 Hz, 1 mT, 260 µs, 1 h/day) and ESWT (3 doses/28 days, 1st dose: 0.12 mJ/mm2 , 15 Hz, 300 impulses; 2nd dose: 0.14 mJ/mm2 , 15 Hz, 500 impulses; 3rd dose: 0.14 mJ/mm2 , 15 Hz, 500 impulses) on rabbits with Achilles tendon injury were investigated in terms of histopathological and biomechanical properties. The clinical feasibility of PEMF application was evaluated by comparing the results of both methods. Fifty New Zealand female rabbits were divided into two groups to be used in either biomechanical or immunohistochemical studies. Each of the two groups was further divided into five groups: C (Control), SH (Sham), TI (tendon injury), TI + ESWT, and TI + PEMF. Biomechanical evaluations revealed that maximum load, toughness, and maximum stress averages of the TI + PEMF group significantly increased (P < 0.05). When immunohistochemical images of the TI + PEMF group were compared with those of the TI group, the amount of fibrous tissue was less, the homogeneity of collagen fibers recovered, and collagen organization was more uniform. We conclude that both ESWT and PEMF are equally efficient for Achilles tendon recovery. PEMF application is effective and can be used in the clinic as a painless alternative treatment method. © 2020 Bioelectromagnetics Society.

Current pharmacological approaches to the treatment of tendinopathy.

INTRODUCTION: Tendinopathies are common in elite and recreational athletes: traditionally considered overuse injuries, they involve excessive tensile loading and subsequent breakdown of the loaded tendon. Many pharmacological treatments have been proposed for the management of tendinopathy, with no agreement regarding the overall best option available both for Achilles and patellar tendinopathy. AREAS COVERED: The present article reports the best scientific evidence regarding the efficacy and safety of different pharmacological treatments in different types of tendinopathy, focusing on Achilles and patellar tendinopathy, the conditions on which more studies have been published. EXPERT OPINION: No univocal evidence exists regarding the best non-operative management, which includes non-steroidal anti-inflammatory drugs, platelet-rich plasma, high volume image-guided injections, hyaluronic acid, and prolotherapy, for tendinopathy (in particular Achilles and patellar tendinopathies) as a suitable alternative to the commonly used eccentric loading rehabilitation regimen. It is unclear whether the combination of pharmacological substances with physical therapy would produce better results than physical therapy alone. There is an overall lack of published well-performed randomized controlled trials comparing the various options available for the management of tendinopathy, studying large cohorts of patients for adequately long follow-up periods and with well-validated standardized scores and scales.

Systematic Review of Photobiomodulation Therapy (PBMT) on the Experimental Calcaneal Tendon Injury in Rats.

This systematic review analyzed the light parameters and the effects of photobiomodulation therapy (PBMT) through low-level laser therapy (LLLT) and/or LED (light-emitting diode) on tendon repair of rats submitted to calcaneal injury. This study was conducted in accordance with the guidelines of the Preferred Reporting Items for Meta-Analysis, and PubMed and MEDLINE databases were accessed to search eligible studies published in English. The search terms were as follows: "Achilles tendon" or "Calcaneal tendon" or "tendon injuries" or "soft tissue injuries" and "tendinopathy" or "tendinitis" and "low-level light therapy" or "low-level laser therapy" or "low intensity power therapy" or "light-emitting diode" or photobiomodulation." The SYRCLE (SYstematic Review Center for Laboratory animal Experimentation) risks of bias was used to assess the risk of bias for selected studies. A total of 225 studies were found based on the descriptors used, and only 33 studies were eligible. Light parameters identified per point of irradiation were approximately 60 mW (continuous mode at infrared spectra), 2 W cm-2 , 2 J and 45 J cm-2 . Light parameters at red spectra, continuous versus pulsed mode, and PBMT combined or compared with other therapies such as ultrasound, and studies using unhealthy rats (ovariectomized and/or diabetic models) were also identified and grouped according to these similarities. The main effects found were decreased inflammatory markers and signs of inflammatory process. PBMT (laser/LED) has positive effects in reducing the inflammatory and time for tissue repair in animal models of tendon injury and/or tendinitis using parameters identified.

Thermal and non-thermal effects off capacitive-resistive electric transfer application on the Achilles tendon and musculotendinous junction of the gastrocnemius muscle: a cadaveric study.

BACKGROUND: Calf muscle strain and Achilles tendon injuries are common in many sports. For the treatment of muscular and tendinous injuries, one of the newer approaches in sports medicine is capacitive-resistive electric transfer therapy. Our objective was to analyze this in vitro, using invasive temperature measurements in cadaveric specimens. METHODS: A cross-sectional study designed with five fresh frozen cadavers (10 legs) were included in this study. Four interventions (capacitive and resistive modes; low- and high-power) was performed for 5 min each by a diathermy "T-Plus" device. Achilles tendon, musculotendinous junction and superficial temperatures were recorded at 1-min intervals and 5 min after treatment. RESULTS: With the low-power capacitive protocol, at 5 min, there was a 25.21% increase in superficial temperature, a 17.50% increase in Achilles tendon temperature and an 11.27% increase in musculotendinous junction temperature, with a current flow of 0.039 A ± 0.02. With the low-power resistive protocol, there was a 1.14% increase in superficial temperature, a 28.13% increase in Achilles tendon temperature and an 11.67% increase in musculotendinous junction temperature at 5 min, with a current flow of 0.063 A ± 0.02. With the high-power capacitive protocol there was an 88.52% increase in superficial temperature, a 53.35% increase in Achilles tendon temperature and a 39.30% increase in musculotendinous junction temperature at 5 min, with a current flow of 0.095 A ± 0.03. With the high-power resistive protocol, there was a 21.34% increase in superficial temperature, a 109.70% increase in Achilles tendon temperature and an 81.49% increase in musculotendinous junction temperature at 5 min, with a current flow of 0.120 A ± 0.03. CONCLUSION: The low-power protocols resulted in only a very slight thermal effect at the Achilles tendon and musculotendinous junction, but current flow was observed. The high-power protocols resulted in a greater temperature increase at the Achilles tendon and musculotendinous junction and a greater current flow than the low-power protocols. The high-power resistive protocol gave the greatest increase in Achilles tendon and musculotendinous junction temperature. Capacitive treatments (low- and high-power) achieved a greater increase in superficial temperature.

Photobiomodulation does not influence maturation and mildly improves functional healing of mouse achilles tendons.

Tendon rupture can occur at any age and is commonly treated nonoperatively, yet can result in persisting symptoms. Thus, a need exists to improve nonoperative treatments of injured tendons. Photobiomodulation (PBM) therapy has shown promise in the clinic and is hypothesized to stimulate mitochondrial-related metabolism and improve healing. However, the effect of PBM therapy on mitochondrial function during tendon maturation and healing are unknown, and its effect on tendon structure and function remain unclear. In this study, near-infrared light (980:810 nm blend, 2.5 J/cm2 ) was applied at low (30 mW/cm2 ) or high (300 mW/cm2 ) irradiance to unilateral Achilles tendons of CD-1 mice during postnatal growth (maturation) as well as adult mice with bilateral Achilles tenotomy (healing). The chronic effect of PBM therapy on tendon structure and function was determined using histology and mechanics, and the acute effect of PBM therapy on mitochondrial-related gene expression was assessed. During maturation and healing, collagen alignment, cell number, and nuclear shape were unaffected by chronic PBM therapy. We found a sex-dependent effect of PBM therapy during healing on mechanical outcomes (eg, increased stiffness and Young's modulus for PBM-treated females, and increased strain at ultimate stress for PBM-treated males). Mitochondria-related gene expression was marginally influenced by PBM therapy for both maturation and healing studies. This study was the first to implement PBM therapy during both growth and healing of the murine tendon. PBM therapy resulted in marginal and sex-dependent effects on the murine tendon. Clinical significance: PBM may be beneficial for tendon healing because functional remodeling improves without adverse effects.

Effects of Pulsed Electromagnetic Field Therapy on Rat Achilles Tendon Healing.

The Achilles tendon is frequently injured. Data to support specific treatment strategies for complete and partial tears is inconclusive. Regardless of treatment, patients risk re-rupture and typically have long-term functional deficits. We previously showed that pulsed electromagnetic field (PEMF) therapy improved tendon-to-bone healing in a rat rotator cuff model. This study investigated the effects of PEMF on rat ankle function and Achilles tendon properties after (i) complete Achilles tendon tear and repair with immobilization, (ii) partial Achilles tendon tear without repair and with immobilization, and (iii) partial Achilles tendon tear without repair and without immobilization. We hypothesized that PEMF would improve tendon properties, increase collagen organization, and improve joint function, regardless of injury type. After surgical injury, animals were assigned to a treatment group: (i) no treatment control, (ii) 1 h of PEMF per day, or (iii) 3 h of PEMF per day. Animals were euthanized at 1, 3, and 6 weeks post-injury. Joint mechanics and gait analysis were assessed over time, and fatigue testing and histology were performed at each time point. Results indicate no clear differences in Achilles healing with PEMF treatment. Some decreases in tendon mechanical properties and ankle function suggest PEMF may be detrimental after complete tear. Some early improvements were seen with PEMF after partial tear with immobilization; however, immobilization was found to be a confounding factor. This body of work emphasizes the distinct effects of PEMF on tendon-to-bone healing and supports trialing potential treatment strategies pre-clinically across tendons before applying them clinically. © 2019 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 38:70-81, 2020.

Long-Term Results With the Use of Modified Percutaneous Repair of the Ruptured Achilles Tendon Under Local Anaesthesia (15-Year Analysis With 270 Cases).

Controversy regarding the optimal treatment of fresh total Achilles tendon rupture remains. This article presents results with the use of modified percutaneous Achilles tendon repair under local anesthesia performed from January 1991 to December 2005 with a 2- to 10-year follow-up. There were 270 procedures in 247 male patients (92.51%) and 20 female patients (7.49%), mean ± SD age 38.7 ± 11.56 (range 20 to 83) years, in all consecutively treated patients within 7 days after acute total rupture; 3 patients sustained ruptures on both sides in different periods. Postoperative care consisted of wearing a cast or soft cast or functional immobilization for 6 weeks. The procedure was well tolerated in all patients. There were 3 (1.11%) complete and 5 (1.85%) partial repeat ruptures (8 [2.96%] altogether). Fourteen patients (5.18%) developed transient sural neuritis that spontaneously resolved in 2 to 10 months. One case (0.3%) of deep venous thrombosis was successfully treated. There were 25 (9.36%) major and minor complications altogether, with no cases of increased postoperative dorsiflexion, deep infection, or necrosis. Forty-four patients (16.48%) had a slightly decreased range of ankle motion, and 216 (80.89%) patients, including all high-caliber athletes, resumed all their previous activities. The mean American Orthopedic Foot and Ankle Society hindfoot-ankle score was 96.10 points. Long-term results of the analyzed modified method suggest a reasonable treatment option for acute total Achilles tendon ruptures, with a low number of complications and repeat rupture rate and return to preinjury activities comparable to those of open procedures.

Spontaneous Closed Rupture of Achilles Tendon Following Minimally Invasive Ultrasonic Energy Therapy: A Report of Two Cases.

This paper presents two patients who sustained spontaneous closed Achilles tendon ruptures following minimally invasive ultrasonic energy therapy for non-insertional Achilles tendinopathy. In both cases, the patients underwent minimally invasive ultrasonic energy therapy using a commercially available device. In addition, the current evidence, through available literature, has been reviewed and presented.

Simvastatin With PRP Promotes Chondrogenesis of Bone Marrow Stem Cells In Vitro and Wounded Rat Achilles Tendon-Bone Interface Healing In Vivo.

BACKGROUND: Tendons and ligaments are joined to bone in a specialized interface that transmits force from muscle to bone and permits body movement. Tendon/ligament injuries always occur in the interface areas, and injured tendons/ligaments have a limited healing response because the insertion site is composed of a fibrocartilaginous zone. PURPOSE: To study the effect of simvastatin with platelet-rich plasma (PRP) on chondrogenesis of rat bone marrow stem cells (BMSCs) in vitro and wounded rat Achilles tendon-bone interface healing in vivo. STUDY DESIGN: Controlled laboratory study. METHODS: The in vitro model was performed by the culture of rat BMSCs with various concentrations of simvastatin (0, 10, 50, 100 nM) for 2 weeks. The effect of simvastatin on the chondrogenic differentiation of the BMSCs was examined by histochemical analysis and real-time quantitative reverse transcription polymerase chain reaction. The in vivo model was carried out by testing the healing effect of simvastatin with PRP on 12 wounded rat Achilles tendon-bone interfaces. RESULTS: Simvastatin induced chondrogenic differentiation of rat BMSCs in a concentration-dependent manner as evidenced by histological staining and real-time quantitative reverse transcription polymerase chain reaction. The wounds treated with simvastatin alone or with simvastatin-containing PRP gel healed much faster than the wounds treated with saline alone or PRP alone. Histological analysis showed that higher percentages of healed tissues were positively stained with safranin O and fast green in wounds treated with simvastatin-containing PRP gel than in the other 3 groups. Immunohistochemical analysis further demonstrated these findings, as evidenced by more positively stained healed tissues with collagen I and II antibodies in the wound areas treated with simvastatin-containing PRP gel than the other 3 groups. CONCLUSION: The combination of simvastatin with PRP induced chondrogenesis of BMSCs in vitro and enhanced fibrocartilage formation in vivo. The simvastatin-PRP gel treatment promotes wounded tendon-bone interface healing in clinical treatment. CLINICAL RELEVANCE: The combination of simvastatin with PRP may be a good clinical treatment for wounded tendon/ligament junction healing, especially for acute sports-related tendon/ligament injuries.

Short-term Changes After Corticosteroid Injections Into the Normal Tendons of Rabbits: A Controlled Randomized Study.

BACKGROUND: Corticosteroid injections in or around tendons for the treatment of athletic injuries are a common practice among orthopaedic surgeons and are apparently efficacious in the short term, although controversies persist related to local complications. PURPOSE: This study evaluated short-term (48 hours) biomechanical, biochemical, and histological alterations after a single injection of betamethasone into the normal tendons of rabbits. STUDY DESIGN: Controlled laboratory study. METHODS: A total of 72 New Zealand White rabbits were randomly divided into 2 groups: the test group-in which 36 animals underwent 1 intratendinous injection of betamethasone (1.4 mg / 0.2 mL) in the right calcaneal tendon; the control group-in which the right calcaneal tendon of 36 animals was injected with saline (placebo control group) and the left calcaneal tendon was left untreated for normal standards (normal control). Forty-eight hours later, animals were euthanized and tendons were harvested. Metalloproteinase (MMP1 and MMP2) and interleukin (IL1 and IL6) expression levels, biomechanical resistance (load × elongation parameters), and histomorphometry (hematoxylin and eosin and picrosirius red stains for collagen fibers, tenocytes, and inflammatory cells) were analyzed in the tendons. RESULTS: The test group had a significant reduction in MMP2 expression as compared with the control groups ( P = .027). Regarding the other parameters, there were no additional significant differences between the groups. CONCLUSION: A single injection of corticosteroid into normal calcaneal tendons did not trigger acute local morphological, structural, or biomechanical injuries at 48 hours, but it did promote a significant decrease in MMP2 levels. Additional studies are needed with increased duration of follow-up, various doses, and multiple injections and in tendinopathic models. CLINICAL RELEVANCE: Some previous studies demonstrated early structural changes in tendons after a single corticosteroid injection, which was not corroborated by the present study. Metalloproteinase decrease is usually associated with a reduction in collagen degradation, which would be protective for the healing process. More studies are necessary to confirm the possible beneficial effect of these results in the long term and for tendinopathies.

The Effect of Pentoxifylline and Hyperbaric Oxygen on Achilles Osteotendinous Junction Injury: An experimental animal model study.

BACKGROUND: To investigate the effects of hyperbaric oxygen (HBO) and pentoxifylline (PTX) treatment on osteotendinous junction healing of Achilles tendon in an animal model. MATERIALS AND METHODS: Thirty-six adult female Wistar-albino rats were randomly divided into three groups as control, PTX and HBO groups with a total of 12 rats per group. Under general anesthesia, the Achilles tendons were cut at the level of the osteotendinous junction and repaired. After the surgery, no treatment was given to the control group. Fifty mg/kg intraperitoneal PTX was administered to the PTX group daily for 1 week. The HBO group was exposed to 2,5 atmospheric pressure, 100% oxygen for 2 hours daily for 1 week. All animals were sacrificed at the end of sixth week. Biomechanical tests and histological examinations were performed. RESULTS: Energy absorption was significantly higher in the PTX group than that in the control group after biomechanical tests (p=0.010). Histopathological evaluation results revealed no difference between the groups: however, hyalinization level was relatively better in the HBO group than that in the control group (p=0.026). CONCLUSIONS: 1. We concluded that PTX has a positive effect on the treatment of osteotendinous junction injuries based on our results. 2. Although HBO therapy did not provide statistically significant differences, it might have some positive effects on these injuries. 3. Further experimental studies and clinical trials should be conducted.

Platelet rich plasma compared to dry needling in the treatment of non-insertional Achilles tendinopathy.

OBJECTIVES: The efficacy of platelet rich plasma in the treatment of Achilles tendinopathy is controversial. Despite positive results observed in open studies, randomized controlled trials failed to show difference against saline or rehabilitation. Aims of this retrospective observational study were to compare the efficacy of platelet-rich plasma and dry needling and to assess possible differences age and sex-related. METHODS: Groups of 46 and 38 patients with non-insertional Achilles tendinopathy were treated with platelet-rich plasma and dry needling (once a week for 3 weeks), respectively. At baseline, 3 and 6 months, pain and function scores and the percentage of satisfactory outcomes were evaluated. Sub-group analyses were performed according to age and sex. RESULTS: At 3 and 6 months no differences in terms of pain and function between groups were observed, but the percentage of subjects reporting satisfactory results, at 6 months, was higher in platelet rich plasma group. Better results were observed in younger subjects, with a greater reduction of pain, improvement of function, and accordingly of the percentage of positive outcomes. A trend toward better results was also observed in males. CONCLUSION: Beneficial effects of platelet rich plasma and dry needling in non-insertional Achilles tendinopathy have been observed only in some subjects, but not in others; platelet rich plasma shows a slight superiority against dry needling, mainly in younger persons; finally, a gender difference in the therapeutic response can be hypothesized.

Effect of electroacupuncture stimulation on long-term recovery following Achilles tendon rupture in a rat model.

AIMS: In this study we examined the effect of electroacupuncture (EA) stimulation on the mechanical strength of the rat Achilles tendon after long-term recovery. METHODS: Using 20 rats, an Achilles tendon rupture model was created in an invasive manner. The rats were assigned to one of three groups, that received EA treatment (EA group), minimal acupuncture (MA group) or remained untreated (Control group). In the EA group, EA stimulation (5 ms, 50 Hz, 20 µA, 20 min) was applied to the rupture region over a period of 90 days (five times/week). In the MA group, needles were inserted into the same positions as in the EA group but no electrical current was applied. After 90 days the tendon was measured to calculate the cross-sectional area of the rupture region. Then, the mechanical strength of the tendon was measured by tensile testing. RESULTS: No significant differences were observed between the three groups in cross-sectional area of the injured tendon. For maximum breaking strength, the EA group showed a significantly higher threshold compared with the Control group (P<0.05) but not the MA group (P=0.24). No significant difference was seen between the MA group and the Control group (P=0.96). CONCLUSION: Given the EA group showed a significant increase in maximum breaking strength, it is likely that EA stimulation increases the mechanical strength of a repaired tendon after long-term recovery, and EA stimulation could be useful for preventing re-rupture.