Pronociceptive and antinociceptive neuromediators in patellar tendinopathy

Challenges and opportunities of medicines for treating tendon inflammation and fibrosis: A comprehensive and mechanistic review

BACKGROUND

Tendinopathy refers to conditions characterized by collagen degeneration within tendon tissue, accompanied by the proliferation of capillaries and arteries, resulting in reduced mechanical function, pain, and swelling. While inflammation in tendinopathy can play a role in preventing infection, uncontrolled inflammation can hinder tissue regeneration and lead to fibrosis and impaired movement.

OBJECTIVES

The inability to regulate inflammation poses a significant limitation in tendinopathy treatment. Therefore, an ideal treatment strategy should involve modulation of the inflammatory process while promoting tissue regeneration.

METHODS

The current review article was prepared by searching PubMed, Scopus, Web of Science, and Google Scholar databases. Several treatment approaches based on biomaterials have been developed.

RESULTS

This review examines various treatment methods utilizing small molecules, biological compounds, herbal medicine-inspired approaches, immunotherapy, gene therapy, cell-based therapy, tissue engineering, nanotechnology, and phototherapy.

CONCLUSION

These treatments work through mechanisms of action involving signaling pathways such as transforming growth factor-beta (TGF-β), mitogen-activated protein kinases (MAPKs), and nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB), all of which contribute to the repair of injured tendons.

Total rupture of Achilles tendon induces inflammatory response and glial activation on the spinal cord of mice

Rupture of Achilles tendon is a common accident affecting professional and recreational athletes. Acute and chronic pain are symptoms commonly observed in patients with rupture. However, few studies have investigated whether Achilles tendon rupture is able to promote disorders in the central nervous system (CNS). Therefore, the current study aimed to evaluate nociceptive alterations and inflammatory response in the L5 lumbar segment of Balb/c mice spinal cord after Achilles tendon rupture. We found increased algesia in the paw of the ruptured group on the 7th and 14th days post-tenotomy compared with the control group. This phenomenon was accompanied by overexpression of cyclooxygenase-2 (COX-2) and inducible nitric oxide synthase-2 (NOS-2) as well as hyperactivation of astrocytes and microglia in nociceptive areas of L5 spinal cord as evidenced by intense GFAP and IBA-1 immunostaining, respectively. Biochemical studies also demonstrated increased levels of nitrite in the L5 spinal cord of tenotomized animals compared with the control group. Thus, we have demonstrated for the first time that total rupture of the Achilles tendon induced inflammatory response and nitrergic and glial activation in the CNS in the L5 spinal cord region.

Endoscopic debridement for non-insertional Achilles tendinopathy with and without platelet-rich plasma

BACKGROUND

When non-operative management fails to improve symptoms in patients with non-insertional Achilles tendinopathy, surgery may be required. Various open and endoscopic techniques have been proposed, and platelet-rich plasma (PRP) injections have been proposed as an adjunct to aid tendon healing.

METHODS

Thirty-six patients with mid-portion Achilles tendinopathy were randomized to undergo endoscopic debridement alone (n = 19) or in combination with intraoperative PRP application (n = 17). Clinical outcome measures included the Visual Analogue Scale for pain, function, and satisfaction and the Victorian Institute of Sports Assessment-Achilles (VISA-A) questionnaire. Patients were followed-up at 6 weeks, 3 months, 6 months, and 12 months after surgery. An MRI examination at 3 and 12 months was used to assess signal alterations within the tendon.

RESULTS

Both groups showed significant clinical improvement (p < 0.05) after surgery, with no difference between the 2 groups. Tendon diameter increased at 3 months and decreased at 12 months. The tendinopathy area increased at 3 months and decreased at 12 months below baseline level in both groups. There was no significant difference between the groups regarding the MRI parameters. Nodular thickening and MRI-detected signal alteration persisted after surgery, with no association between imaging and clinical outcome. Five minor complications were reported: 2 in the PRP group and 3 in the control group.

CONCLUSION

Endoscopic debridement of the Achilles tendon improved clinical outcomes in patients with mid-portion tendinopathy. The addition of PRP did not improve outcomes compared to debridement alone. MRI parameters showed no association with clinical outcomes.

Is neurogenic inflammation involved in tendinopathy? A systematic review

Neurogenic pain and inflammation have been hypothesised to play an important role in tendinopathy. This systematic review aimed to present and assess the evidence on neurogenic inflammation in tendinopathy. A systematic search was conducted through multiple databases to identify human case-control studies assessing neurogenic inflammation through the upregulation of relevant cells, receptors, markers and mediators. A newly devised tool was used for the methodological quality assessment of studies. Results were pooled based on the cell/receptor/marker/mediator assessed. A total of 31 case-control studies were eligible for inclusion. The tendinopathic tissue was obtained from Achilles (n=11), patellar (n=8), extensor carpi radialis brevis (n=4), rotator cuff (n=4), distal biceps (n=3) and gluteal (n=1) tendons. Through pooling the results of included studies based on the marker of neurogenic inflammation assessed, we identified possible upregulation of protein gene product 9.5 (PGP 9.5), N-methyl-D-aspartate Receptors, glutamate, glutamate receptors (mGLUT), neuropeptide Y (NPY) and adrenoreceptors in tendinopathic tissue versus control. Calcitonin gene-related peptide (CGRP) was not found to be upregulated, and the evidence was conflicting for several other markers. These findings show the involvement of the glutaminergic and sympathetic nervous systems and the upregulation of nerve ingrowth markers supporting the concept that neurogenic inflammation plays a role in tendinopathy.

Tendon pain - what are the mechanisms behind it?

OBJECTIVES

Management of chronic tendon pain is difficult and controversial. This is due to poor knowledge of the underlying pathophysiology of chronic tendon pain, priorly known as tendinitis but now termed tendinopathy. The objective of this topical review was to synthesize evolving information of mechanisms in tendon pain, using a comprehensive search of the available literature on this topic.

CONTENT

This review found no correlations between tendon degeneration, collagen separation or neovascularization and chronic tendon pain. The synthesis demonstrated that chronic tendon pain, however, is characterized by excessive nerve sprouting with ingrowth in the tendon proper, which corresponds to alterations oberserved also in other connective tissues of chronic pain conditions. Healthy, painfree tendons are devoid of nerve fibers in the tendon proper, while innervation is confined to tendon surrounding structures, such as sheaths. Chronic painful tendons exhibit elevated amounts of pain neuromediators, such as glutamate and substance p as well as up-regulated expression and excitability of pain receptors, such as the glutamate receptor NMDAR1 and the SP receptor NK1, found on ingrown nerves and immune cells. Increasing evidence indicates that mast cells serve as an important link between the peripheral nervous system and the immune systems resulting in so called neurogenic inflammation.

SUMMARY

Chronic painful tendons exhibit (1) protracted ingrowth of sensory nerves (2) elevated pain mediator levels and (3) up-regulated expression and excitability of pain receptors, participating in (4) neuro-immune pathways involved in pain regulation. Current treatments that entail the highest scientific evidence to mitigate chronic tendon pain include eccentric exercises and extracorporeal shockwave, which both target peripheral neoinnervation aiming at nerve regeneration.

OUTLOOK

Potential mechanism-based pharmacological treatment approaches could be developed by blocking promotors of nerve ingrowth, such as NGF, and promoting inhibitors of nerve ingrowth, like semaphorins, as well as blocking glutamate-NMDA-receptor pathways, which are prominent in chronic tendon pain.

Histologic grading correlates with inflammatory biomarkers in tibialis posterior tendon dysfunction

BACKGROUND

It has been theorized that tibialis posterior tendon dysfunction (TPTD) is a degenerative process unrelated to inflammation. The purpose of this study was to determine if inflammatory cytokines, matrix metalloproteases (MMPs), and glutamate were elevated in diseased tibialis posterior tendons (TPTs).

METHODS

Matched diseased TPT, TPT insertion, and flexor digitorum longus (FDL) samples were collected from 21 patients. The samples were individually incubated in media, which was analyzed for inflammatory cytokines, MMPs, and glutamate. Histology and statistical analyses were performed.

RESULTS

Diseased TPT and TPT insertion were significantly elevated compared to transferred FDL in eight inflammatory markers (p < 0.005). Only the diseased TPT was significantly elevated compared to the transferred FDL tendons for glutamate (p < 0.01). Histologic grading correlated with inflammatory cytokine levels.

CONCLUSION

Diseased TPT and TPT insertion demonstrated significantly elevated levels of inflammatory markers compared to the transferred tendons used as controls, suggesting a role for inflammation in the disease process. The amount of inflammation correlated with increased tendon degradation.

LEVEL OF EVIDENCE

Level III.

The Influence of Different Modes of Exercise on Healthy and Injured Tendons

Tendons are essential components of the musculoskeletal system that links the skeletal muscle to the skeleton. This dense connective tissue exhibits great plasticity. Therefore, research on the influence of types of exercise, including acute and long-term training, on the structural and mechanical properties of tendons in athletic and sedentary populations is of critical importance in the design of scientific-based exercise plans and effective tendinopathy treatment. Here, we review recent studies on the relationship between exercise and tendon health and tendinopathy repair to provide a general understanding of how exercise may reshape tendons.

Biological response of extracorporeal shock wave therapy to tendinopathy in vivo (review)

Tendinopathy is a degenerative disease of the tendons caused by prolonged overstretching or overuse of the tendons. It accounts for a large proportion of musculoskeletal disorders which can occur in all age groups. The management of tendinopathy is typically conservative. In clinical practice, when other conservative treatments fail, extracorporeal shock wave therapy (ESWT) is normally used as an efficient alternative to surgical management. Several basic studies have shown that ESWT with lower energy flux densities can produce some biological responses in vivo to tendinopathy and may accelerate the initiation of the healing process in injured tendons. ESWT has a positive impact on the interactive chain of biological response, enhancing the signaling pathways of angiogenesis through mechanical conduction, and promoting cell proliferation and collagen formation. Finally, it helps tissue regeneration by controlling inflammation. The purpose of this review is to summarize the biological responses generated by ESWT in tendinopathy through a comprehensive review of the published literature. Although ESWT has been used clinically for the treatment of tendinopathies for nearly decades, less is known about the experimental studies of its biological effects on tendon tissue. Further studies on the biological response of ESWT for tendon injuries in vivo are needed in the future in order to provide better management to patients.

Nearly half of patients with chronic tendinopathy may have a neuropathic pain component, with significant differences seen between different tendon sites: a prospective cohort of more than 300 patients

Objectives

Identifying the prevalence of neuropathic pain components in patients with chronic tendinopathy conditions using the Self-Administered Leeds Assessment of Neuropathic Symptoms and Signs (S-LANSS) questionnaire.

Methods

Patients with chronic tendinopathy and ‘tendon-like’ conditions treated within a single hospital outpatient clinic specialising in tendinopathy were identified. Pain scores, plus global function patient-reported outcome measures (5-Level version of EuroQol-5 Dimension and Musculoskeletal Health Questionnaire (MSK-HQ)), were completed and compared with the S-LANSS questionnaire

Results

341 suitable patients with chronic tendinopathy and potentially similar conditions were identified. Numbers: lateral elbow tendinopathy (39), greater trochanteric pain syndrome (GTPS; 112), patellar tendinopathy (11), non-insertional Achilles tendinopathy (40), insertional Achilles tendinopathy (39), plantar fasciopathy (100). 68% were female, with a mean age of 54.0±11.3 years and a mean symptom duration of 38.1±33.7 months.

There was a mean S-LANSS score of 11.4±6.4. Overall, 47% of patients scored 12 or greater points on S-LANSS, indicating the possible presence of neuropathic pain. The highest proportion was in patients with plantar fasciopathy (61%), the lowest in those with GTPS (33%). Weak correlations were found between the S-LANSS score and MSK-HQ score, the numerical rating scale (0–10) values for ‘average pain’ and for ‘worst pain’, but not with the MSK-HQ %health value.

Conclusion

S-LANSS identified nearly half of patients with chronic tendinopathy as possibly having a neuropathic pain component. This is of unclear clinical significance but worth further study to see if/how this may relate to treatment outcomes. These results are from a single hospital clinic dealing with patients with chronic tendinopathy, without a control group or those with shorter symptom duration. However, this reinforces the probability of neuropathic pain components in at least some patients with chronic tendinopathy.

High-Volume Image-Guided Injections in Achilles and Patellar Tendinopathy in a Young Active Military Population: A Double-Blind Randomized Controlled Trial

Background:

Chronic Achilles and patellar tendinopathy are a significant burden in physically active populations. High-volume image-guided injection (HVIGI) proposes to strip away associated neovascularity, disrupt painful nerve ingrowth, and facilitate rehabilitation.

Purpose:

To investigate the efficacy of HVIGI with and without steroid relative to placebo.

Study Design:

Randomized controlled trial; Level of evidence, 1.

Methods:

A total of 62 participants were recruited between May 25, 2016, and March 5, 2020. Participants were men aged 18 to 55 years with Achilles or patellar tendinopathy of at least 6-month chronicity that had not improved with nonoperative management (including physical therapy and shockwave therapy), with ultrasound evidence of neovascularization, tendon thickening, and echogenic changes. They were assigned to the following groups: control (3 mL of subcutaneous 0.5% bupivacaine), HVIGI (10 mL of 0.5% bupivacaine and 30 mL of normal saline, ultrasound-guided between tendon and underlying fat pad), or HVIGI with steroid (HVIGIwSteroid; 0.25 mL of 100 mg/mL hydrocortisone). Clinicians and assessors were blinded. All participants were supervised through a pain-guided progressive loading program for 6 months postinjection. The main outcome measures were the Victoria Institute of Sport Assessments (VISA) for Achilles and patellar tendinopathy and the visual analog scale (VAS) for pain at 6 months postinjection.

Results:

The VISA score improved by a mean of 22.8 points (95% CI, 10.4-35.3 points; effect size [ES], 1.51) in the control group (n = 21), 18.6 points (95% CI, 9.1-28.0 points; ES, 1.31) in the HVIGI group (n = 21), and 18.5 points (95% CI, 3.4-33.6 points; ES, 0.88) in the HVIGIwSteroid group (n = 20). VAS pain improved by a mean of 15 points (interquartile range [IQR], –38.75, 8 points; ES, 0.39) in controls, 13 points (IQR,–34.0, 3.75 points; ES, 0.47) in the HVIGI group, and 27 points (IQR,–38.0, –1.0 points; ES, 0.54) in the HVIGIwSteroid group. The main effects were significant for time (P < .001) but not group (P ≥ .48), with no group × time interaction (P = .71). One participant was lost to follow-up from each group, multiple imputation was used for missing data points. No adverse events occurred.

Conclusion:

Study findings did not demonstrate superiority of HVIGI over control injection.

Registration:

EU Clinical Trials Register (EudraCT: 2015-003587-36).

Radiofrequency Microtenotomy or Physical Therapy for Achilles Tendinopathy: Results of a Randomized Clinical Trial

Background:

Achilles tendinopathy is a painful disorder, and various treatment options are available. Bipolar radiofrequency microtenotomy (RFM) has shown promising results in treating tendinosis.

Purpose/Hypothesis:

The purpose was to compare the results between treatment with bipolar RFM and physical therapy (PT) for patients with midportion Achilles tendinopathy. It was hypothesized that RFM would be equivalent or superior to PT.

Study Design:

Randomized controlled trial; Level of evidence, 1.

Methods:

A total of 38 patients with midportion Achilles tendinopathy were evaluated for 2 years. The patients were randomized to receive either RFM or PT. There were 20 patients in the RFM group and 18 patients in the PT group. Clinical outcomes were assessed using the visual analog scale (VAS) for pain and the Foot and Ankle Outcome Score (FAOS). The degree of tendinosis was evaluated with magnetic resonance imaging (MRI) of the affected ankle performed before intervention and 2 years after intervention.

Results:

In both groups, the VAS scores at the 2-year follow-up were significantly improved compared with preintervention: from 7.2 ± 1.5 to 1.0 ± 1.4 for the RFM group and from 5.9 ± 1.3 to 3.1 ± 1.8 for the PT group (P < .01 for both). Compared with the PT group, the RFM group had significantly better VAS scores at both the 1- and 2-year follow-ups (P < .01 for both) and better scores on 4 of the 5 FAOS subscales at the 2-year follow-up (P < .01 for all). MRI revealed an improvement in the tendinosis score in both groups, without any significant difference between the groups.

Conclusion:

In this randomized study, the clinical assessments revealed significant improvements in the VAS, FAOS, and tendinosis score as seen on MRI 2 years after intervention with either RFM or PT in patients with midportion Achilles tendinopathy. The improvement was significantly better in the RFM group with regard to VAS and FAOS, but not in the MRI appearance.

Registration:

NCT03274557 (ClinicalTrials.gov identifier).

Hierarchical ultrastructure: An overview of what is known about tendons and future perspective for tendon engineering

Abnormal tendons are rarely ever repaired to the natural structure and morphology of normal tendons. To better guide the repair and regeneration of injured tendons through a tissue engineering method, it is necessary to have insights into the internal morphology, organization, and composition of natural tendons. This review summarized recent researches on the structure and function of the extracellular matrix (ECM) components of tendons and highlight the application of multiple detection methodologies concerning the structure of ECMs. In addition, we look forward to the future of multi-dimensional biomaterial design methods and the potential of structural repair for tendon ECM components. In addition, focus is placed on the macro to micro detection methods for tendons, and current techniques for evaluating the extracellular matrix of tendons at the micro level are introduced in detail. Finally, emphasis is given to future extracellular matrix detection methods, as well as to how future efforts could concentrate on fabricating the biomimetic tendons.

•

Summarize recent research on the structure and function of the extracellular matrix (ECM) components of tendons.

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Comments on current research methods concerning the structure of ECMs.

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Perspective on the future of multi-dimensional detection techniques and structural repair of tendon ECM components.

Expression of Substance P and Nerve Growth Factor in Degenerative Long Head of Biceps Tendon in Patients with Painful Rotator Cuff Tear

Purpose

Degenerative long head of biceps tendon (LHBT) has been recognized as a notable pain source in patients with rotator cuff tear (RCT). Tenotomy or tenodesis of LHBT is frequently indicated together with arthroscopic rotator cuff repair (ARCR) aiming for complete pain relief; however, it has not been fully investigated whether resected LHBT is really a source of pain. The purpose of this study was to investigate expression levels of pain-associated mediators in LHBT and its association with preoperative pain profiles.

Methods

Twenty-seven RCT patients who underwent ARCR with LHBT resection were included. Each LHBT was resected due to its abnormal arthroscopic findings including tenosynovitis, hypertrophy, and partial tear. Worst macroscopic lesion of the LHBT was obtained, and expression levels of substance P (SP) and nerve growth factor (NGF) were evaluated using enzyme-linked immunosorbent assay (ELISA). Ten healthy knee flexor tendons were analyzed as non-degenerative samples. Preoperatively, subjective shoulder pain VAS and pain duration were investigated. Conventional LHBT pain provocation tests (Speed, Yergason, O’Brien) were performed. Pressure pain threshold (PPT) of bilateral LHBT on the groove was recorded.

Results

Levels of SP and NGF expression were significantly higher compared with non-degenerative tendons (P<0.01). Shoulder pain VAS and pain duration were not directly associated with SP and NGF expression level. Patients with positive O’Brien test expressed greater SP than negative patients (P=0.001). Significant negative correlation between the PPT ratio (ipsilateral/contralateral) and SP expression level was observed (r=−0.453, P=0.034).

Conclusion

Greater expression of SP and NGF in degenerative LHBT supported our hypothesis that it would be a pain source in RCT patients. SP was likely to be expressed highly in patients with localized pressure pain hypersensitivity and positive O’Brien test (ie, altered mechanistic pain profile of LHBT), which may help when considering simultaneous LHBT resection during ARCR.

Clinical Registration

UMIN000023943.

Extracorporeal shockwave treatment in knee osteoarthritis: therapeutic effects and possible mechanism

Osteoarthritis (OA), the most common degenerative joint disease, is characterized by the cardinal symptoms of chronic pain and restricted joint activity. The complicated pathological changes associated with OA and unclear mechanistic etiology have rendered existing non-surgical OA management options unsatisfactory. Increasing clinical and experimental evidence suggests that extracorporeal shockwave therapy (ESWT) is beneficial in OA treatment. ESWT is found to have modifying effects on cartilage and subchondral bone alterations in OA progression, as well as the clinical complaints of patients, including chronic pain and limited joint activities. However, the specific treatment strategy regarding the dosage and frequency of ESWT is still underdetermined. This review discusses the existing evidence regarding the therapeutic indications and possible mechanism of ESWT for OA treatment.

Correlation between smoking and neovascularization in biceps tendinopathy: a functional preoperative and immunohistochemical study

Aims

The purpose of this study was to investigate whether smoking is associated with neovascularization in the tendinopathy of the long head of the biceps tendon (LHBT).

Methods

The study included 40 consecutive patients who underwent arthroscopic biceps tenotomy/tenodesis due to chronic biceps tendinopathy and divided into three groups: (1) non-smokers, (2) former smokers, (3) smokers. LHBT tissue samples were stained with H&E, Alcian blue and Trichrome staining. Immunohistochemical examination was performed using anti-CD31 and anti-CD34. The neovessel density score (NDS) was scored by Bonar criteria.

Results

The mean period of smoking was 15.50 years with an average number of 24 cigarettes/day in the former smokers and 21.69 years with an average number of 15 cigarettes/day in the active smokers. The mean NDS was 2.23/3 in non-smokers, whereas it was 1.60/3 in former smokers and 1.31/3 in active smokers. The mean American Shoulder and Elbow Surgeons score equaled 46 in never smoked patients, 43.60 in former smokers, and 41.46 in active smokers. In the patients with smoking history, the disorganized tendinous tissue islands were avascular and composed of compact acidic polysaccharides and mucopolysaccharides. We observed negative correlation between the NDS and the smoking indexes, including cigarettes per day (p = 0.0150), smoking years (p = 0.0140), pack-years (p = 0.0088).

Conclusion

In conclusion, the present study revealed that smoking impairs the vascularization of the biceps tendon in chronic tendinopathy. Clinically, we observed a negative correlation between smoking and neovascularization. Furthermore, there was no correlation between neovascularization and functional preoperative status.

Do Mast Cells Have a Role in Tendon Healing and Inflammation?

Understanding the links between the tendon healing process, inflammatory mechanisms, and tendon homeostasis/pain after tissue damage is crucial in developing novel therapeutics for human tendon disorders. The inflammatory mechanisms that are operative in response to tendon injury are not fully understood, but it has been suggested that inflammation occurring in response to nerve signaling, i.e., neurogenic inflammation, has a pathogenic role. The mechanisms driving such neurogenic inflammation are presently not clear. However, it has recently been demonstrated that mast cells present within the injured tendon can express glutamate receptors, raising the possibility that mast cells may be sensitive to glutamate signaling and thereby modulate neurogenic inflammation following tissue injury. In this review, we discuss the role of mast cells in the communication with peripheral nerves, and their emerging role in tendon healing and inflammation after injury.

Study protocol for a randomised controlled trial with clinical, neurophysiological, laboratory and radiological outcome for surgical versus non-surgical treatment for lumbar spinal stenosis: the Uppsala Spinal Stenosis Trial (UppSten)

INTRODUCTION

Symptomatic lumbar spinal stenosis is the most common indication for spinal surgery. However, more than one-third of the patients undergoing surgery for lumbar stenosis report dissatisfaction with the results. On the other hand, conservative treatment has shown positive results in some cases. This trial will compare the outcomes of surgical versus non-surgical treatment for lumbar stenosis. The study includes a multidimensional follow-up, aiming to study the association between outcome and other studied parameters, mainly electromyography and nerve conduction. Moreover, it may contribute to a better understanding of the pathophysiology of lumbar stenosis and to the development of future pharmacological treatments.

METHODS AND ANALYSIS

UppSten is a single-centre randomised controlled trial in which 150 patients with symptomatic lumbar spinal stenosis will be randomised into one of two treatment arms. The patients in the surgical arm will undergo laminectomy; the patients in the non-surgical arm will be given a structured physical training programme. The primary outcome of the study will be the Oswestry Disability Index. Secondary outcomes will include motor amplitude and degree of denervation activity obtained by means of nerve conduction studies and electromyography. Patient-reported outcome measures will be also used as secondary outcomes. Blood sample analysis and the investigation of potential inflammation markers are the additional secondary outcome parameters. Laboratory evaluation will include blood sample collection before the treatment initiation and after 6 months. Flavum ligament biopsies will be performed in the surgical group. Finally, tertiary outcomes will include neurophysiological measures, the objective walking ability and radiological evaluation.

ETHICS AND DISSEMINATION

The study is approved by the Local Ethics Committee (Dnr 2017-506), the Hospital's Clinical Trials Committee (2018-0001) and the National Biobank Council and Uppsala Biobank (BbA-827-2018-025). The results will be presented in peer-reviewed journals and at international conferences.

TRIAL REGISTRATION NUMBER

NCT03495661.

The Effectiveness of Shockwave Therapy in Patients with Lateral Epicondylitis

Shockwave therapy is based on generating a very intense energy in a very short period of time. It creates a mechanical pressure over the affected tissues that leads to an increased cellular permeability, thus increasing the microcirculation and the cellular metabolism. Therefore, the healing process is accelerated. Lateral epicondylitis represents a common arm injure, which usually affects early to late middle-aged patients, more common and with a longer evolution period in women, characterized by inflammation of the arm muscles’ tendon insertion and manifests with pain on elbow extension and forearm rotation. Our study aims to investigate the efficacity of the shockwave therapy in comparison with a classical treatment of local and systemic drugs. The 50 patients were evenly split into two groups. The diagnosis of lateral epicondylitis was based on exhaustive physical examination. Enthesis evaluation was performed through power Doppler ultrasound. The pain was quantified using the visual analogue scale for pain intensity. All parameters were evaluated at diagnosis and after 30 days, following treatment. One group received shockwave therapy, while the other group received nonsteroidal anti-inflammatory drugs and local topics associated with laser and ultrasound application. The results of our study report that both groups experienced significant improvement after treatment. The shockwave therapy recorded a higher improvement rate in all the parameters. Consequently, this new non-invasive, effective and safe technique can be successfully used in the treatment of abarticular pathology of the elbow.

Neurodynamic tests for patellofemoral pain syndrome: a pilot study

Background

Patellofemoral pain syndrome (PFPS) is a common musculoskeletal disorder. There is little consensus on the etiology, but one explanatory model suggests that PFPS can be caused by referred pain. Neurodynamic tests are used to explore the mechanosensitivity of peripheral nerves, and previous studies have shown a relationship between increased mechanosensitivity and anterior knee pain by using the femoral slump test (FST). Previously the prone knee bend test (PKB) does not appear to have been included. The main purpose of this pilot study was to examine whether there was an identifiable difference in mechanosensitivity between left and right sides that could be identified using both the PKB and FST tests for the femoral nerve in patients with unilateral PFPS.

Methods

This cross-sectional pilot study tested 12 patients with unilateral PFPS for altered mechanosensitivity using both PKB and FST. The pain-free knee was used as a control. The selected test procedures were similar to those clinicians use in everyday practice.

Results

8 and 4 of the 12 patients were found to have increased levels of mechanosensitivity in the PFPS leg using the PKB and FST, respectively. Both tests provoked stronger pain in the leg with PFPS compared with the asymptomatic leg (p < 0.05 Wilcoxon Signed Rank Test). The symptoms were more often located in the anterior knee, with structural differentiation by neck flexion appearing to increase the symptoms more when testing the leg with PFPS.

Conclusions

Although the reliability of the tests is unknown and the study sample size was small, the PKB and FST test procedures used in clinical practice appear capable of revealing altered mechanosensitivity in unilateral PFPS patients. The PKB test appears to detect mechanosensitivity in more patients than the FST. We recommend including both tests in future larger blinded controlled studies which should also assess reliability of the tests.

Trial registration

ISRCTN 12473526. Registered 20 May 2015, retrospectively registered.

Lateral epicondylalgia: A primary nervous system disorder

Lateral epicondylalgia (LE) is the most common chronic painful condition affecting the elbow in the general population. Although major advances have been accomplished in recent years in the understanding of LE, the underlying physiopathology is still a reason for debate. Differences in clinical presentation and evolution of the symptoms among patients, suggest the need for revisiting the current knowledge about subjacent mechanisms that attempt to explain pain and functional loss. Previous models have suggested that the condition is mainly a degenerative tendinopathy, associated with changes in pain pathways and the motor system. The hypothesis of this work is that LE is the clinical manifestation of a primary nervous system disorder, characterized by an abnormal increase in neuronal activity and a subsequent loss of homeostasis, which secondarily affects the musculoskeletal tissues of the elbow-forearm-hand complex. A new model for LE is presented, supported by an in-deep analysis of basic sciences, epidemiological and clinical studies.

Crosstalk between substance P and calcitonin gene-related peptide during heterotopic ossification in murine Achilles tendon

Heterotopic ossification (HO) is abnormal bone formation within soft tissue, usually predisposed by neurogenic or musculoskeletal trauma. Inflammation resulting from trauma is considered to be the main trigger for HO by eliciting changes within the injury site, including elevation of bone morphogenetic proteins (BMPs). Recent research, however, has also associated changes in sensory neuropeptide expression with HO. Substance P (SP) and calcitonin gene-related peptide (CGRP) are two of those neuropeptides that have been implicated with various aspects of HO, including regulation of inflammation and BMP signaling. Despite discoveries associating SP and CGRP with soft tissue HO, it remains unclear whether SP and CGRP have a direct role in the induction of HO. Here, we investigated the effect of SP and CGRP in vivo with the aid of inkjet-based biopatterning technology to controllably deliver these neuropeptides onto a murine Achilles tendon. While we did not observe any significant effect with CGRP, SP alone promoted HO in vivo with increased expression of BMP2. Remarkably, when SP and CGRP were delivered together, CGRP counteracted the effect of SP and essentially blocked SP-induced HO. This report contributes to the understanding of the complex problem of HO pathophysiology and warrants more study to better elucidate the interplay between SP and CGRP in the induction of HO. © 2017 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 36:1444-1455, 2018.

Sport and exercise medicine consultants are reliable in assessing tendon neovascularity using ultrasound Doppler

OBJECTIVE

Several lower limb tendinopathy treatment modalities involve identification of pathological paratendinous or intratendinous neovascularisation to target proposed co-location of painful neoneuralisation. The ability to reliably locate and assess the degree of neovascularity is therefore clinically important. The Modified Ohberg Score (MOS) is frequently used to determine degree of neovascularity, but reliability has yet to be established among Sport and Exercise Medicine (SEM) consultants. This study aims to determine inter-rater and intra-rater reliability of an SEM consultant cohort when assessing neovascularity using the 5-point MOS.

METHOD

Eleven participants (7 male and 4 female) provided 16 symptomatic Achilles and patella tendons. These were sequentially examined using power Doppler (PD) enabled ultrasound (US) imaging by 6 SEM consultants who rated neovascular changes seen using the MOS. Representative digital scan images were saved for rescoring 3 weeks later. Inter-rater and intra-rater reliability of the MOS was examined using intraclass correlation coefficient (ICC) and Kappa Agreement scores.

RESULTS

Neovascular changes were reported in 65.6% of 96 scans undertaken. ICC for inter-rater reliability was 0.86 and Fleiss Kappa 0.52. ICC for intra-rater reliability was 0.95 and Weighted Kappa 0.91.

CONCLUSIONS

Neovascular changes were present in two-thirds of symptomatic tendons. Excellent SEM consultant inter-rater and intra-rater reliability was demonstrated. These findings support the use of PD-enabled US to assess neovascularity by appropriately experienced SEM consultants. Furthermore, future interventional research using a similarly experienced SEM consultant cohort can be undertaken with assurance that assessment of neovascularity will be reliable.

The Implication of Substance P in the Development of Tendinopathy: A Case Control Study

It was reported that substance P had beneficial effects in the healing of acute tendon injury. However, the relationship between substance P and degenerative tendinopathy development remains unclear. The purpose of this study was to determine the role of substance P in the pathogenesis of tendinopathy. Healthy and tendinopathy tendon were harvested from human and tenocytes were cultured individually. The expression levels of genes associated with tendinopathy were compared. Next, substance P was exogenously administered to the healthy tenocyte and the effect was evaluated. The results showed that tendinopathy tenocytes had higher levels of COL3A1, MMP1, COX2, SCX, ACTA2, and substance P gene expression compared to healthy tenocytes. Next, substance P treatment on the healthy tenocyte displayed similar changes to that of the tendinopathy tenocytes. These differences between the two groups were also determined by Western blot. Additionally, cells with substance P had the tendinopathy change morphologically although cellular proliferation was significantly higher compared to that of the control group. In conclusion, substance P enhanced cellular proliferation, but concomitantly increased immature collagen (type 3 collagen). Substance P plays a crucial role in tendinopathy development and could be a future therapeutic target for treatment.

Study protocol: a double blind randomised control trial of high volume image guided injections in Achilles and patellar tendinopathy in a young active population

Background

Chronic tendinopathy is a significant problem particularly in active populations limiting sporting and occupational performance. The prevalence of patellar tendinopathy in some sports is near 50% and the incidence of lower limb tendinopathy is 1.4% p.a. in the UK Military. Management includes isometric, eccentric, heavy slow resistance exercises and extracorporeal shockwave therapy (ESWT). Often these treatments are inadequate yet there is no good evidence for injection therapies and success rates from surgery can be as low as 50%.

High Volume Image Guided Injection (HVIGI) proposes to strip away the neovascularity and disrupt the nerve ingrowth seen in chronic cases and has shown promising results in case series. This study aims to investigate the efficacy of HVIGI in a randomised controlled trial (RCT).

Methods

RCT comparing 40ml HVIGI, with or without corticosteroid, with a 3ml local anaesthetic sham-control injection. Ninety-six participants will be recruited. Inclusion criteria: male, 18–55 years old, chronic Achilles or patellar tendinopathy of at least 6 months, failed conservative management including ESWT, and Ultrasound (US) evidence of neovascularisation, tendon thickening and echogenic changes. Outcome measures will be recorded at baseline, 6 weeks, 3, 6 and 12 months. Primary outcome measures include The Victoria Institute of Sport Assessments for Achilles and patellar tendinopathy (VISA-A and VISA-P) and VAS pain. Secondary outcome measures include Modified Ohberg score, maximum tendon diameter and assessment of hypoechoic appearance on US, and Functional Activity Assessment.

Discussion

Despite previous interventional trials and reviews there is still insufficient evidence to guide injectable therapy for chronic tendinopathy that has failed conservative treatment. The scant evidence available suggests HVIGI has the greatest potential however there is no level one RCT evidence to support this. Investigating the efficacy of HVIGI against control in a RCT and separating the effect of HVIGI and corticosteroid will add high level evidence to the management of chronic tendinopathy resistant to conservative treatment.

Trial Registration

EudraCT: 2015-003587-36 3 Dec 2015

Midsubstance Tendinopathy, Surgical Management

Noninsertional Achilles tendinopathy often responds to nonoperative treatment. When nonoperative treatment fails, the clinician must distinguish between paratendinopathy and noninsertional tendinopathy. In paratendinopathy, myofibroblasts synthesize collagen, causing adhesions, and the paratenon may be released or excised. If a core area of tendinopathy is identified on MRI, the area is excised longitudinally and repaired with a side-to-side suture. If greater than 50% of the tendon diameter is excised, the authors recommend a short flexor hallucis longus tendon transfer with an interference screw. A turndown flap of the gastrocnemius aponeurosis is also described with good results.

The effects of substance P and acetylcholine on human tenocyte proliferation converge mechanistically via TGF-β1

Previous in vitro studies on human tendon cells (tenocytes) have demonstrated that the exogenous administration of substance P (SP) and acetylcholine (ACh) independently result in tenocyte proliferation, which is a prominent feature of tendinosis. Interestingly, the possible link between SP and ACh has not yet been explored in human tenocytes. Recent studies in other cell types demonstrate that both SP and ACh independently upregulate TGF-β1 expression via their respective receptors, the neurokinin 1 receptor (NK-1R) and muscarinic ACh receptors (mAChRs). Furthermore, TGF-β1 has been shown to downregulate NK-1R expression in human keratocytes. The aim of this study was to examine if TGF-β1 is the intermediary player involved in mediating the proliferative pathway shared by SP and ACh in human tenocytes. The results showed that exogenous administration of SP and ACh both caused significant upregulation of TGF-β1 at the mRNA and protein levels. Exposing cells to TGF-β1 resulted in increased cell viability of tenocytes, which was blocked in the presence of the TGFβRI/II kinase inhibitor. In addition, the proliferative effects of SP and ACh on tenocytes were reduced by the TGFβRI/II kinase inhibitor; this supports the hypothesis that the proliferative effects of these signal substances are mediated via the TGF-β axis. Furthermore, exogenous TGF-β1 downregulated NK-1R and mAChRs expression at both the mRNA and protein levels, and these effects were negated by simultaneous exposure to the TGFβRI/II kinase inhibitor, suggesting a negative feedback loop. In conclusion, the results indicate that TGF-β1 is the intermediary player through which the proliferative actions of both SP and ACh converge mechanistically.

Tendinopathy in diabetes mellitus patients-Epidemiology, pathogenesis, and management

Chronic tendinopathy is a frequent and disabling musculo-skeletal problem affecting the athletic and general populations. The affected tendon is presented with local tenderness, swelling, and pain which restrict the activity of the individual. Tendon degeneration reduces the mechanical strength and predisposes it to rupture. The pathogenic mechanisms of chronic tendinopathy are not fully understood and several major non-mutually exclusive hypotheses including activation of the hypoxia-apoptosis-pro-inflammatory cytokines cascade, neurovascular ingrowth, increased production of neuromediators, and erroneous stem cell differentiation have been proposed. Many intrinsic and extrinsic risk/causative factors can predispose to the development of tendinopathy. Among them, diabetes mellitus is an important risk/causative factor. This review aims to appraise the current literature on the epidemiology and pathology of tendinopathy in diabetic patients. Systematic reviews were done to summarize the literature on (a) the association between diabetes mellitus and tendinopathy/tendon tears, (b) the pathological changes in tendon under diabetic or hyperglycemic conditions, and (c) the effects of diabetes mellitus or hyperglycemia on the outcomes of tendon healing. The potential mechanisms of diabetes mellitus in causing and exacerbating tendinopathy with reference to the major non-mutually exclusive hypotheses of the pathogenic mechanisms of chronic tendinopathy as reported in the literature are also discussed. Potential strategies for the management of tendinopathy in diabetic patients are presented.

Role of VEGF, Nitric Oxide, and Sympathetic Neurotransmitters in the Pathogenesis of Tendinopathy: A Review of the Current Evidences

Chronic tendinopathy is a painful common condition affecting athletes as well as the general population undergoing to tendon overuse. Although its huge prevalence, little is known about tendinopathy pathogenesis, and even cloudier is its treatment. Traditionally, tendinopathy has been defined as a lack of tendon ability to overcome stressing stimuli with appropriate adaptive changes. Histologic studies have demonstrated the absence of inflammatory infiltrates, as a consequence conventional antinflammatory drugs have shown little or no effectiveness in treating tendinopathies. New strategies should be therefore identified to address chronic tendon disorders. Angiofibroblastic changes have been highlighted as the main feature of tendinopathy, and vascular endothelial growth factor (VEGF) has been demonstrated as one of the key molecules involved in vascular hyperplasia. More recently, attention has been focused on new peptides such as Substance P, nitric oxide, and calcitonin gene-related peptide (CGRP). Those new findings support the idea of a nerve-mediated disregulation of tendon metabolism. Each of those molecules could be a target for new treatment options. This study aimed to systematically review the current available clinical and basic science in order to summarize the latest evidences on the pathophysiology and its effect on treatment of chronic tendinopathy, and to spread suggestions for future research on its treatment.

Manipulation Therapy Relieved Pain More Rapidly Than Acupuncture among Lateral Epicondylalgia (Tennis Elbow) Patients: A Randomized Controlled Trial with 8-Week Follow-Up

Radial bone adjustment manipulation treatment may be effective to reduce pain rapidly in lateral epicondylalgia patients and the pathological tension in the biceps brachii muscle is highly concerned. To prove this hypothesis, we conducted a randomized controlled trial and included 35 patients with lateral epicondylalgia for more than 2 months. Either manipulation treatment (n = 16) or acupuncture (n = 19) was given to these patients for 2 weeks and all patients' symptoms were followed up for 8 weeks after treatment. Both groups demonstrated changes in pain VAS score, grip strength, and DASH questionnaire. Lateral epicondylalgia patients who received manipulation treatment felt pain relief sooner than those who had acupuncture treatments during the first few treatments. However, both acupuncture and manipulation are effective, while the difference has no significance at the 8-week follow-up. The trial was registered with Current Controlled Trials ISRCTN81308551 on 5 February 2016.

Ultrasonic Percutaneous Tenotomy for Recalcitrant Lateral Elbow Tendinopathy: Sustainability and Sonographic Progression at 3 Years

BACKGROUND

A previously published study found positive outcomes for a novel technique for ultrasound-guided percutaneous ultrasonic tenotomy, showing good tolerability, safety, and early efficacy within an office setting.

PURPOSE

In this follow-up study, all 20 members of the original cohort were contacted after 3 years to explore the sustainability of symptomatic relief, functional improvement, and sonographic soft tissue response for percutaneous ultrasonic tenotomy.

STUDY DESIGN

Case series; Level of evidence, 4.

METHODS

All 20 subjects of the clinical trial that was performed from June to November 2011 were further assessed at 36 months after the procedure in terms of visual analog scale for pain, Disabilities of the Arm, Shoulder and Hand (DASH)-Compulsory/Work scores, need for adjunct procedures, and overall satisfaction. Importantly, all 20 were reassessed with ultrasound imaging at 36 months, and evidence of the common extensor tendon response was assessed in terms of tendon hypervascularity, tendon thickness, and the progress of the hypoechoic scar tissue.

RESULTS

A 100% clinical follow-up was achieved, inclusive of ultrasonographic assessment. None of the subjects required further treatment procedures, and 100% expressed satisfaction. Previous improvements in visual analog scale (current median ± SD, 0 ± 0.9; range, 0-3) and DASH-Work scores (current median, 0 ± 0) were sustained with conformity to a linear pattern on polynomial measures. There was further reduction in DASH-Compulsory scores to a median of 0 ± 0.644 (range, 0-2) with a significant decrease on repeated measures (P = .008). Tendon hypervascularity was resolved in 94% of patients, and 100% had reduction in tendon thickness. Overall reduction in the hypoechoic scar tissue was observed in all subjects, with a 90% response achieved by 6 months. Between 6 and 36 months, further reduction in the scar was observed in around 60% of patients, with 20% of patients having complete resolution of the hypoechoic scar.

CONCLUSION

Minimally invasive percutaneous ultrasonic tenotomy provided sustained pain relief and functional improvement for recalcitrant tennis elbow at 3-year follow-up. It is one of the few procedures to demonstrate positive sonographic evidence of tissue-healing response and is an attractive alternative to surgical intervention for definitive treatment of recalcitrant elbow tendinopathy.

The sympathetic nervous system and tendinopathy: a systematic review

BACKGROUND

Tendinopathy is a clinical diagnosis of localised tendon pain often confirmed by imaging findings. The pathophysiological cause of the pain is unknown and the sympathetic nervous system (SNS) may be implicated.

OBJECTIVE

To review what is known regarding the role of the SNS in human tendinopathy.

STUDY SELECTION

Published data describing sympathetic innervation or an index of sympathetic activity in human tendons were eligible for inclusion.

DATA SOURCES

Bibliographical databases (AMED, Biological Abstracts, CINAHL Plus, EMBASE, MEDLINE, Scopus, SPORTDiscus and Web of Science) were searched for relevant articles. Reference lists from included articles were screened for additional articles.

STUDY APPRAISAL

Studies were scored with a quality assessment tool to identify potential sources of bias. Each question had an explicit decision rule to guide assessment.

RESULTS

Nine case-control and four cross-sectional studies examined sympathetic innervation of tendons. There was evidence suggesting a lack of difference in sympathetic innervation of tendon proper between tendinopathy biopsies and healthy controls. In contrast, the paratendinous tissue showed evidence of increased sympathetic innervation in painful tendons. The most notable increase in SNS markers was seen in abnormal tenocytes from painful tendons. Data from two studies were suitable for meta-analysis. These heterogeneous studies revealed no difference in sympathetic innervation between painful and pain-free tendons. No studies recorded SNS activity in vivo.

CONCLUSION

Sympathetic innervation in painful tendons depends on tissue type. Abnormal tenocytes may have increased capacity for self-production of sympathetic neurotransmitters. Future insight may be gained by measuring global in vivo sympathetic drive in tendinopathy.

Interventional articular and para-articular knee procedures

The knee is a common area of the body to undergo interventional procedures. This article discusses image-guided interventional issues specific to the knee area. The soft tissues in and around the knee are frequently affected by sport-related injuries and often need image-guided intervention. This article details the specific technical issues related to intervention in these soft tissues, including the iliotibial tract, fat pads, patellar tendon and other tendons, bursae and the meniscus. Most often, simple procedures such as injection and aspiration are performed without image guidance. Rarely image-guided diagnostic arthrography and therapeutic joint injections are necessary. The technique, indications and diagnostic considerations for arthrography are discussed in this article. Primary bone and soft-tissue tumours may involve the knee and adjacent soft tissues. Image-guided biopsies are frequently necessary for these lesions; this article details the technical issues related to image-guided biopsy around the knee. A number of newer ablation treatments are now available, including cryoablation, high-frequency ultrasound and microwave ablation. Radiofrequency ablation, however, still remains the most commonly employed ablation technique. The indications, technical and therapeutic considerations related to the application of this technique around the knee are discussed here. Finally, we briefly discuss some newer, but as of yet, unproven image-guided interventions for osteochondral lesions and Brodie's abscess.

Effect of highly purified capsaicin on articular cartilage and rotator cuff tendon healing: An in vivo rabbit study

Highly purified capsaicin has emerged as a promising injectable compound capable of providing sustained pain relief following a single localized treatment during orthopedic surgical procedures. To further assess its reliability for clinical use, the potential effect of highly purified capsaicin on articular cartilage metabolism as well as tendon structure and function warrants clarification. In the current study, rabbits received unilateral supraspinatus transection and repair with a single 1 ml injection of capsaicin (R+C), PEG-only placebo (R+P), or saline (R+S) into the glenohumeral joint (GHJ). An additional group received 1 ml capsaicin onto an intact rotator cuff (I+C). At 18 weeks post-op, cartilage proteoglycan (PG) synthesis and content as well as cell viability were similar (p>0.05) across treatment groups. Biomechanical testing revealed no differences (p>0.05) among tendon repair treatment groups. Similarly, histologic features of both cartilage and repaired tendons showed minimal differences across groups. Hence, in this rabbit model, a single injection of highly purified capsaicin into the GHJ does not induce a deleterious response with regard to cartilage matrix metabolism and cell viability, or rotator cuff healing. These data provide further evidence supporting the use of injectable, highly purified capsaicin as a safe alternative for management of postoperative pain following GHJ surgery.

Effectiveness of extracorporeal shockwave therapy in three major tendon diseases

BACKGROUND

Extracorporeal shockwave therapy is a conservative treatment for several painful musculoskeletal disorders. The aim of the study was the assessment of the relief from pain by the shockwave therapy in a population of consecutive patients affected by specific pathologies.

MATERIALS AND METHODS

A group of consecutive patients were studied and treated. They were affected by calcific tendonitis of the shoulder (129 patients), chronic Achilles tendinopathy (102 patients), and lateral epicondylitis of the elbow (80 subjects). Each patient had 3 applications with a monthly interval, and was followed up at 1, 6, and 12 months after treatment. Results were evaluated by the numeric rating scale (NRS) in all cases, the Constant Murley Score for the assessment of the shoulder function, the American Orthopaedic Foot and Ankle Society Score for subjects affected by chronic Achilles tendinopathy, and the Oxford Elbow Score for those affected by a lateral epicondylitis of the elbow.

RESULTS

One year after treatment, the results were considered satisfactory with an almost complete resolution of symptoms. There were statistically significant results at the 12-month follow-ups regarding the mean NRS score (from 6.25 to 0.2), the Constant Murley Score (from 66.7 to 79.4), the Oxford Elbow Score (from 28 to 46), and the AOFAS (from 71 to 86).

CONCLUSIONS

Extracorporeal shockwave therapy may be considered a safe, economic, and effective treatment for several chronic musculoskeletal disorders, allowing satisfactory pain relief and improvement of function ability.

LEVEL OF EVIDENCE

Level IV.

Increased CCN2, substance P and tissue fibrosis are associated with sensorimotor declines in a rat model of repetitive overuse injury

Key clinical features of cumulative trauma disorders include pain, muscle weakness, and tissue fibrosis, although the etiology is still under investigation. Here, we characterized the temporal pattern of altered sensorimotor behaviors and inflammatory and fibrogenic processes occurring in forearm muscles and serum of young adult, female rats performing an operant, high repetition high force (HRHF) reaching and grasping task for 6, 12, or 18 weeks. Palmar mechanical sensitivity, cold temperature avoidance and spontaneous behavioral changes increased, while grip strength declined, in 18-week HRHF rats, compared to controls. Flexor digitorum muscles had increased MCP-1 levels after training and increased TNFalpha in 6-week HRHF rats. Serum had increased IL-1beta, IL-10 and IP-10 after training. Yet both muscle and serum inflammation resolved by week 18. In contrast, IFNγ increased at week 18 in both muscle and serum. Given the anti-fibrotic role of IFNγ, and to identify a mechanism for the continued grip strength losses and behavioral sensitivities, we evaluated the fibrogenic proteins CCN2, collagen type I and TGFB1, as well as the nociceptive/fibrogenic peptide substance P. Each increased in and around flexor digitorum muscles and extracellular matrix in the mid-forearm, and in nerves of the forepaw at 18 weeks. CCN2 was also increased in serum at week 18. At a time when inflammation had subsided, increases in fibrogenic proteins correlated with sensorimotor declines. Thus, muscle and nerve fibrosis may be critical components of chronic work-related musculoskeletal disorders. CCN2 and substance P may serve as potential targets for therapeutic intervention, and CCN2 as a serum biomarker of fibrosis progression.

Histopathological, biomechanical, and behavioral pain findings of Achilles tendinopathy using an animal model of overuse injury

Animal models of forced running are used to study overuse tendinopathy, a common health problem for which clear evidence for effective and accessible treatments is still lacking. In these models, pain evaluation is necessary to better understand the disease, help design and evaluate therapies, and ensure humane treatment of the animals. Therefore, the main objective of this study was to evaluate pain and pathologic findings in an animal model of moderate Achilles tendinopathy induced by treadmill running. Air puffs, instead of electrical shocks, were used to stimulate running so that pain associated with stimulation would be avoided. Pressure pain sensitivity was evaluated in vivo using a new instrumented plier, whereas spinal cord peptides were analyzed ex vivo with high‐performance liquid chromatography tandem mass spectrometry. Tendon histologic slides were semiquantitatively evaluated, using the Bonar score technique and biomechanical properties, using the traction test. After 8 weeks of treadmill running (2 weeks for adaptation and 6 weeks for the lesion protocol), the protocol was stopped because the air puffs became ineffective to stimulate running. We, nevertheless, observed some histologic changes characteristic of overuse tendinopathy as well as decreased mechanical properties, increased Substance P and dynorphin A peptides but without pressure pain sensitivity. These results suggest that air‐puffs stimulation is sufficient to induce an early stage tendinopathy to study new therapeutic drugs without inducing unnecessary pain. They also indicate that pain‐associated peptides could be related with movement evoked pain and with the sharp breakdown of the running performance.

The main objective of this study was to correlate pain and pathologic findings in an animal model of moderate Achilles tendinopathy induced by treadmill running. We observed some histologic changes characteristic of overuse tendinopathy as well as decreased mechanical properties, increased Substance P and dynorphin A peptides but without pressure pain sensitivity.

Rehabilitation protocol for patellar tendinopathy applied among 16- to 19-year old volleyball players

The aim of the study was to investigate the efficacy of rehabilitation protocol applied during competitive period for the treatment of patellar tendinopathy. A total of 28 male volleyball players were divided into two groups. Fifteen from experimental group (E) and 13 from control group (C) fulfilled the same tests 3 times: before the training program started (first measurement), after 12 weeks (second measurement) and after 24 weeks (third measurement). The above-mentioned protocol included the following: USG imagining with color Doppler function, clinical testing, pain intensity evaluation with VISA-P questionnaire, leg muscle strength and power and jumping ability measurements. The key element of the rehabilitation program was eccentric squat on decline board with additional unstable surface. The essential factor of the protocol was a set of preventive functional exercises, with focus on eccentric exercises of hamstrings. Patellar tendinopathy was observed in 18% of the tested young volleyball players. Implementation of the presented rehabilitation protocol with eccentric squat on decline board applied during sports season lowered the pain level of the young volleyball players. Presented rehabilitation protocol applied without interrupting the competitive period among young volleyball players together with functional exercises could be an effective method for the treatment of patellar tendinopathy.

Effect of radiofrequency microtenotomy on degeneration of tendons: an experimental study on rabbits

INTRODUCTION

Radiofrequency microtenotomy is used to enhance healing by increasing vascularity in the degenerated tendon. In the present study, the effect of radiofrequency microtenotomy (Rf-mt) treatment on tendon degeneration was investigated.

MATERIALS AND METHODS

A total of 32 New Zealand rabbits were enrolled in the current study. Experimental degeneration was performed by injecting prostaglandin E1 (PGE1) into the bilateral Achilles tendons of rabbits. After excluding 4 rabbits with an infection on the injection site, 4 other rabbits were sacrificed to define the histopathologic changes in the tendons. The remaining 24 rabbits were divided into 2 groups: the control group and the Rf-mt group. In the control group, the Rf-mt device was only applied to the Achilles tendon without running the device. In the Rf-mt group, the Rf-mt device was applied bilaterally at the fourth energy level for 500ms to an area within 2cm proximal to the insertion site at 0.5cm intervals in order to form a grid. Six rabbits from each group were sacrificed at 6 and 12 weeks. The Achilles tendons were evaluated histopathologically by a modified Movin scale and by immunohistopathologic staining for vascular endothelial growth factor and type 4 collagen.

RESULTS

After the PGE1 injection, findings similar to chronic degenerative tendinopathy were observed. The Rf-mt group showed significant improvement in vascularity in the histopathological and immunohistochemical examination (P<0.05). However, there was no significant difference in healing between the control and Rf-mt groups (P>0.05).

CONCLUSIONS

Rf-mt treatment increases vascularity in degenerated tendons but does not create difference to facilitate the healing process comparing control group.

Current concepts in examination and treatment of elbow tendon injury

Context:

Injuries to the tendons of the elbow occur frequently in the overhead athlete, creating a significant loss of function and dilemma to sports medicine professionals. A detailed review of the anatomy, etiology, and pathophysiology of tendon injury coupled with comprehensive evaluation and treatment information is needed for clinicians to optimally design treatment programs for rehabilitation and prevention.

Evidence Acquisitions:

The PubMed database was searched in January 2012 for English-language articles pertaining to elbow tendon injury.

Results:

Detailed information on tendon pathophysiology was found along with incidence of elbow injury in overhead athletes. Several evidence-based reviews were identified, providing a thorough review of the recommended rehabilitation for elbow tendon injury.

Conclusions:

Humeral epicondylitis is an extra-articular tendon injury that is common in athletes subjected to repetitive upper extremity loading. Research is limited on the identification of treatment modalities that can reduce pain and restore function to the elbow. Eccentric exercise has been studied in several investigations and, when coupled with a complete upper extremity strengthening program, can produce positive results in patients with elbow tendon injury. Further research is needed in high-level study to delineate optimal treatment methods.

Clinical characteristics of pain originating from intra-articular structures of the knee joint in patients with medial knee osteoarthritis

Purpose

Although disease progression of osteoarthritis has been well documented, pain pathophysiology is largely unknown. This study was designed with two purposes: 1) to characterize patients with knee pain predominantly originating from intra-articular structures and 2) to describe the location and pattern of their pain.

Materials and methods

103 patients with medial knee osteoarthritis underwent an intra-articular injection of local anesthetics (joint block). At least 70% pain relief was defined as positive for the joint block, while less than 50% as negative. Pain characteristics in patients positive for joint block were evaluated in detail using a knee pain map.

Results

Sixty three knees (61%) were positive and 33 knees (32%) were negative. Patients negative for the joint block were significantly higher age, suffered for longer time, and complained more diffuse pain. Although pain at anterior medial area during walk was the most common finding, pain characteristics differed among different knee areas.

Conclusion

The characteristics of joint pain are widely variable even in patients with similar radiological features. Extra-articular sources are not negligible especially in older patients with a long history of diffuse pain. Differences in pain characteristics among knee areas should be taken into account when examining the pain source.

Influence of Comorbidities: Neuropathy, Vasculopathy, and Diabetes on Healing Response Quality

SIGNIFICANCE

Prolonged and nonhealing connective tissue injuries are often seen associated with common diseases, such as metabolic disorders, obesity, hypertension, arteriosclerosis, neuropathy, and diabetes mellitus and these influences result in considerable burden on society via the health care system, the economy, and quality of life for patients.

RECENT ADVANCES

Emerging findings have established important new links in our understanding of effective connective tissue healing. Thereby, the function of the nervous system, vascular supply, and metabolic state of the patient can be directly linked to the quality of the connective tissue healing process.

CRITICAL ISSUES

As some of these conditions are also more common in individuals as they age, and aging can also impact healing effectiveness, such complications will have an emerging significant impact as the demographics of many societies change with expanding percentages of the populations >60-65 years of age.

FUTURE DIRECTIONS

Comorbidities have to be early identified in patients with acute wounds or planned surgery. Necessary interactions between physicians with different subspecialties have to be initiated to optimize wound healing potentials.