Molecular composition and pathology of entheses on the medial and lateral epicondyles of the humerus: a structural basis for epicondylitis

Prevalence and factors associated with lateral epicondylitis among hospital healthcare workers

Background

Hospital healthcare workers have been reported to have a high prevalence of musculoskeletal disorders, but their association with lateral epicondylitis (LE) is unknown. This study aimed to clarify the prevalence of LE and its associated factors among hospital healthcare workers.

Methods

The present study included all staff members of a secondary emergency hospital who provided their consent to participate. Participants with a history of elbow joint trauma were excluded from this study. The diagnostic criteria for definite LE were: (1) pain in the elbow joint within 2 weeks of the study; (2) pain in the lateral epicondyle region on resisted extension of the wrist with the elbow extended; and (3) tenderness in the lateral epicondyle. The diagnosis of LE was defined by meeting all criteria. Age, height, weight, sex, dominant hand, occupation, years of employment, smoking history, drinking history, personal computer usage history, and smartphone usage history were investigated using a questionnaire. A physical examination, in addition to evaluation of pain in the lateral epicondyle, grip strength and wrist extension strength were measured. A statistical analysis was used to assess the prevalence of LE and its associated factors. All investigations, including the diagnosis of LE, were performed by a single orthopedic specialist.

Results

We evaluated 544 individuals, corresponding to approximately 80% of all staff members. The median age was 39 years (interquartile range, 30-48). The study population included 154 males and 390 females. The occupations of the participants were as follows: nurses (n = 265), doctors (n = 47), clerks (n = 93), therapists (n = 27), certified care workers (n = 23), medical technologists (n = 22), pharmacists (n = 19), and others (n = 48). LE was diagnosed in 30 limbs/30 individuals with a prevalence of approximately 5.5%. There was no difference in the prevalence of LE among occupations (P = .85). A logistic regression analysis revealed that age (odds ratio, 1.05; 95% confidence interval 1.01-1.1; P = .01) and smoking history (odds ratio, 2.94; 95% confidence interval 1.01-8.56; P = .04) were independently associated with LE.

Conclusion

This study was conducted to evaluate the prevalence of LE among hospital healthcare workers. The prevalence of LE was 5.5%, and LE was independently associated with age and smoking history.

Treating Lateral Epicondylopathy With Dry Needling and Exercise: A Case Series

CONTEXT

Lateral epicondylopathy (LE) is a common overuse injury affecting elbow, wrist, and hand function. It is characterized by weakness and pain in the muscles and tendons of the forearm responsible for the extension of your wrist and fingers. Trigger point dry needling is a technique reported to be beneficial in managing pain and dysfunction after LE diagnosis. LE is also commonly treated with conservative treatment, such as joint and soft tissue mobilization, self-care home programs, and anti-inflammatory use. We explored a different dry needling approach consisting of in situ dry needling with electric stimulation combined with targeted therapeutic exercise to treat LE in 3 cases.

CASE PRESENTATION

Three patients were referred for dry needling once a week for 6 weeks and home-based exercise therapy for LE. They were clinically evaluated using grip strength, a visual analog scale to assess pain, and Patient-Rated Tennis Elbow Evaluation Test scores. These were measured at 4 time points (weeks 0, 2, 4, and 6).

MANAGEMENT AND OUTCOMES

The dry needling intervention incorporated 8 locations in the upper-extremity with 2 electric stimulation channels. The patients had reduced pain as measured by a visual analog scale, increased function as measured by the Patient-Rated Tennis Elbow Evaluation Test, and increased grip strength over 6 weeks.

CONCLUSIONS

This case series illustrates the use of dry needling and a home exercise program to provide a favorable outcome in a patient with LE. Patients had an 80% to 100% reduction in pain and similar improvements in function that were significantly beyond the minimum clinically important difference. This dry needling approach is a safe and effective treatment of LE in the short term.

Imaging in inflammatory arthritis: progress towards precision medicine

Imaging techniques such as ultrasonography and MRI have gained ground in the diagnosis and management of inflammatory arthritis, as these imaging modalities allow a sensitive assessment of musculoskeletal inflammation and damage. However, these techniques cannot discriminate between disease subsets and are currently unable to deliver an accurate prediction of disease progression and therapeutic response in individual patients. This major shortcoming of today's technology hinders a targeted and personalized patient management approach. Technological advances in the areas of high-resolution imaging (for example, high-resolution peripheral quantitative computed tomography and ultra-high field MRI), functional and molecular-based imaging (such as chemical exchange saturation transfer MRI, positron emission tomography, fluorescence optical imaging, optoacoustic imaging and contrast-enhanced ultrasonography) and artificial intelligence-based data analysis could help to tackle these challenges. These new imaging approaches offer detailed anatomical delineation and an in vivo and non-invasive evaluation of the immunometabolic status of inflammatory reactions, thereby facilitating an in-depth characterization of inflammation. By means of these developments, the aim of earlier diagnosis, enhanced monitoring and, ultimately, a personalized treatment strategy looms closer.

Are the Pathologic Features of Enthesopathy, Tendinopathy, and Labral and Articular Disc Disease Related to Mucoid Degeneration? A Systematic Review

BACKGROUND

Tendinopathy, enthesopathy, labral degeneration, and pathologic conditions of the articular disc (knee meniscus and ulnocarpal) are sometimes described in terms of inflammation or damage, while the histopathologic findings are often consistent with mucoid degeneration. A systematic review of the histopathology of these structures at diverse locations might reconceptualize these diseases as expected aspects of human aging. The potential benefits of this evolution might include healthier patient and clinician mindsets as well as a reduced likelihood of overdiagnosis and overtreatment resulting from greater awareness of base rates of pathology.

QUESTION/PURPOSE

In this systematic review of studies of surgical specimens, we asked: Are there are any differences in the histopathologic findings of structural soft tissue conditions (mucoid degeneration, inflammation, and vascularity) by anatomic site (foot, elbow, or knee) or structure (tendon body, muscle or tendon origin or insertion [enthesis], labrum, or articular disc)?

METHODS

Studies between 1980 and 2021 investigating the histopathologic findings of specimens from surgery for trigger digit, de Quervain tendinopathy, plantar fasciitis, lateral and medial elbow enthesopathy, rotator cuff tendinopathy, posterior tibial tendinopathy, patellar tendinopathy, Achilles tendinopathy, or disease of the hip labrum, ulnocarpal articular disc, or knee meniscus were searched for in the PubMed, EMBASE, and CINAHL databases. Inclusion criteria were the prespecified anatomic location or structure being analyzed histologically and any findings described with respect to inflammation, vascularity, or mucoid degeneration. Studies were excluded if they were nonhuman studies or review articles. Search terms included "anatomy," "pathology," and "histopathology." These terms were coupled with anatomic structures or disorders and included "trigger finger," "de Quervain," "fasciitis, plantar," "tennis elbow," "rotator cuff tendinopathy," "elbow tendinopathy," "patellar tendonitis," "posterior tibial tendon," and "triangular fibrocartilage." This resulted in 3196 studies. After applying the inclusion criteria, 559 articles were then assessed for eligibility according to our exclusion criteria, with 52 eventually included. We recorded whether the study identified the following histopathologic findings: inflammatory cells or molecular markers, greater than expected vascularity (categorized as quantitative count, with or without controls; molecular markers; or qualitative judgments), and features of mucoid degeneration (disorganized collagen, increased extracellular matrix, or chondroid metaplasia). In the absence of methods for systematically evaluating the pathophysiology of structural (collagenous) soft tissue structures and rating histopathologic study quality, all studies that interpreted histopathology results were included. The original authors' judgment regarding the presence or absence of inflammation, greater than expected vascularity, and elements of mucoid degeneration was recorded along with the type of data used to reach that conclusion.

RESULTS

Regarding differences in the histopathology of surgical specimens of structural soft tissue conditions by anatomic site, there were no differences in inflammation or mucoid degeneration, and the knee meniscus was less often described as having greater than normal vascularity. There were no differences by anatomic structure. Overall, 20% (10 of 51) of the studies that investigated for inflammation reported it (nine inflammatory cells and one inflammatory marker). Eighty-three percent (43 of 52) interpreted increased vascularity: 40% (17 of 43) using quantitative methods (14 with controls and three without) and 60% (26 of 43) using imprecise criteria. Additionally, 100% (all 52 studies) identified at least one element of mucoid degeneration: 69% (36 of 52) reported an increased extracellular matrix, 71% (37 of 52) reported disorganized collagen, and 33% (17 of 52) reported chondroid metaplasia.

CONCLUSION

Our systematic review of the histopathology of diseases of soft tissue structures (enthesopathy, tendinopathy, and labral and articular disc) identified consistent mucoid degeneration, minimal inflammation, and imprecise assessment of relative vascularity; these findings were consistent across anatomic sites and structures, supporting a reconceptualization of these diseases as related to aging (senescence or degeneration) rather than injury or activity.

CLINICAL RELEVANCE

This reconceptualization supports accommodative mindsets known to be associated with greater comfort and capability. In addition, awareness of the notable base rates of structural soft tissue changes as people age might reduce overdiagnosis and overtreatment of incidental, benign, or inconsequential signal changes and pathophysiology.

Anatomy and Sonographic Examination for Lateral Epicondylitis: EURO-MUSCULUS/USPRM Approach

OBJECTIVE

The aim of the study is to define a standardized comprehensive sonographic approach for evaluating the different histoanatomical compartments of the lateral elbow.

DESIGN

Using high-frequency ultrasound probes, we tried to match the anatomical features of the lateral elbow and its different sonographic patterns in patients with the diagnosis of lateral epicondylitis. Moreover, high-sensitive color/power Doppler assessments have also been performed to evaluate the microcirculation.

RESULTS

Modern ultrasound equipment seems to provide an extremely detailed sonographic assessment of the different anatomical layers located in the lateral compartment of the elbow. Moreover, high-sensitive color/power Doppler imaging allows for clear visualization of the perfusion patterns in pathological conditions.

CONCLUSIONS

In clinical practice, high-frequency B-mode and high-sensitive color/power Doppler imaging can be integrated with the clinical findings to better define the pain generator(s) for optimizing the management of patients with lateral epicondylitis.

Ultrasonography for Injecting (Around) the Lateral Epicondyle: EURO-MUSCULUS/USPRM Perspective

Lateral epicondylitis (LE) is a very common and painful condition seen in the daily practice of musculoskeletal physicians. Ultrasound-guided (USG) injections are commonly performed to manage the pain, promote the healing phase, and plan a tailored rehabilitation treatment. In this aspect, several techniques were described to target specific pain generators i the lateral elbow. Likewise, the aim of this manuscript was to extensively review those USG techniques together with the patients' pertinent clinical/sonographic features. The authors believe that this literature summary could also be refined as a practical, ready-to-use guide for planning the USG interventions of the lateral elbow in clinical practice.

Non-invasive metabolic profiling of inflammation in joints and entheses by multispectral optoacoustic tomography

OBJECTIVE

To explore the metabolic characteristics of arthritis and enthesitis using multispectral opto-acoustic tomography (MSOT), a technology using near-infrared multispectral laser to stimulate tissues and detect the emitted acoustic energy, enabling non-invasive quantification of tissue components in vivo based on differential absorbance at multiple wavelengths.

METHODS

We performed a cross-sectional study in patients with RA or PsA and healthy controls (HCs). Participants underwent clinical, ultrasonographic and MSOT examination of MCP and wrist joints as well as the entheses of the common extensor tendon at the lateral humeral epicondyles and of the patellar, quadriceps and Achilles tendon. MSOT-measured haemoglobin (Hb), oxygen saturation, collagen and lipid levels were quantified and scaled mean differences between affected and unaffected joints and entheses were calculated as defined by clinical examination or ultrasonography using linear mixed effects models.

RESULTS

We obtained 1535 MSOT and 982 ultrasonography scans from 87 participants (34 PsA, 17 RA, 36 HCs). Entheseal tenderness was not associated with significant metabolic changes, whereas enthesitis-related sonographic changes were associated with increased total Hb, oxygen saturation and collagen content. In contrast, the presence of arthritis-related clinical and sonographic findings showed increased Hb levels, reduced oxygen saturation and reduced collagen content. Synovial hypertrophy was associated with increased lipid content in the joints.

CONCLUSION

MSOT allows determination of distinct metabolic differences between arthritis and enthesitis in a non-invasive setting in humans in vivo.

Tendon Aging

Tendons are mechanosensitive connective tissues responsible for the connection between muscles and bones by transmitting forces that allow the movement of the body, yet, with advancing age, tendons become more prone to degeneration followed by injuries. Tendon diseases are one of the main causes of incapacity worldwide, leading to changes in tendon composition, structure, and biomechanical properties, as well as a decline in regenerative potential. There is still a great lack of knowledge regarding tendon cellular and molecular biology, interplay between biochemistry and biomechanics, and the complex pathomechanisms involved in tendon diseases. Consequently, this reflects a huge need for basic and clinical research to better elucidate the nature of healthy tendon tissue and also tendon aging process and associated diseases. This chapter concisely describes the effects that the aging process has on tendons at the tissue, cellular, and molecular levels and briefly reviews potential biological predictors of tendon aging. Recent research findings that are herein reviewed and discussed might contribute to the development of precision tendon therapies targeting the elderly population.

Lateral Elbow Pain and Muscle Function Impairments

Although often described as a self-limiting condition and likely to resolve on its own, high recurrence rates and extended sick leave frame a need for effective non-surgical treatment for people with lateral elbow tendinopathy. The interrelationship of histological and structural changes to the tendon, the associated impairments in motor control, and potential changes in pain processing may all drive symptoms. This clinical practice guideline covers the epidemiology, functional anatomy and pathophysiology, risk factors, clinical course, prognosis, differential diagnosis, tests and measures, and interventions for managing lateral elbow tendinopathy in the physical therapy clinic. J Orthop Sports Phys Ther 2022;52(12):CPG1-CPG111. doi:10.2519/jospt.2022.0302.

Tenodesis with bone marrow venting under local anesthesia for recalcitrant lateral epicondylitis: Results of 2 years of follow-up

Hypothesis

We hypothesized that the treatment of recalcitrant lateral epicondylitis requires accurate identification of the painful area to promote remodeling of the degenerated extensor insertion and to stabilize the tendon origin during tendon healing. Thus, we performed tenodesis with bone marrow venting under local anesthesia for recalcitrant lateral epicondylitis.

Methods

Twenty patients (21 elbows) were treated with bone marrow venting at the painful area of the lateral epicondyle of the elbow and tenodesis using 2 soft anchors lateral to the capitellum (immediately distal to the painful area) and were followed up for ≥2 years. Patients were assessed using the numerical rating scale for pain and the Quick Disabilities of the Arm, Shoulder, and Hand questionnaire, and objective evaluation included active range of motion.

Results

The mean preoperative and postoperative pain scores were 7.5 and 0.5, respectively, indicating significant pain relief (P < .001). The mean preoperative and postoperative Quick Disabilities of the Arm, Shoulder, and Hand questionnaire scores were 44.2 and 1.0, respectively (P < .001). Two elbows had a slightly positive Thomsen test at the final visit. No recurrence of intra-articular symptoms induced by synovial fringe impingement was observed. Patients experienced more pain at the bone-tendon junction of extensors than at the tendon parenchyma.

Conclusion

Tenodesis with bone marrow venting under local anesthesia was effective for subjective patient satisfaction and positive clinical outcomes at ≥2 years of follow-up in patients with recalcitrant lateral epicondylitis. Intra-articular symptoms can be improved by stabilization of the lateral soft tissue without treatment for intra-articular lesions.

Lateral ulnar collateral ligament (LUCL) reconstruction for the treatment of recalcitrant lateral epicondylitis of the elbow: a comparison with open débridement of the extensor origin

Background

Based on the controversy over whether the extensor tendon is the only lesion of lateral epicondylitis of the elbow and numerous reports of concomitant lateral collateral ligament involvement, potential damage to the lateral collateral ligament complex should be considered for the treatment.

Methods

About 25 elbows in 23 patients (débridement group) and 22 elbows in 20 patients (reconstruction group) who were diagnosed with lateral epicondylitis and had an average of 22 months of symptoms revealing anatomical lesion on MRI were included. The capitellum-sublime tubercle-radial head (CSR) angle was measured on both sides preoperatively, and the visual analog scale (VAS) and Mayo elbow performance score (MEPS) were measured over 12 months, postoperatively.

Results

The initial preoperative mean VAS was statistically significant with 4.6 in the débridement group and 6.5 in the reconstruction group (P < .05). Postoperative VAS was continuously decreased in both groups with no significant difference at each assessment period (P < .05) but showed more rapid improvement in the reconstruction group compared with the débridement group. For MEPS, the reconstruction group showed significant improvement during the follow-up periods, and at the final follow-up MEPS, 3 cases in the débridement group and 0 cases in the reconstruction group showed a poor result, which was considered as surgery failure. The CSR angle of the affected side (7.2 ± 1.9) was significantly larger than that of the normal side (3.6 ± 1.5) (P < .05) in the reconstruction group. Increased CSR by more than 5 degrees was identified as a significant predictive indicator for potential concomitant ligament insufficiency (area under curve = 0.875, P < .001) showing 80.9% of the sensitivity, 82.1% of the specificity.

Conclusions

In the surgical treatment of recalcitrant lateral epicondylitis, lateral ulnar collateral ligament reconstruction added to the débridement of extensor origin may provide better results for the patients with suspicious lateral ligament insufficiency or failed previous surgery.

Lateral Epicondylitis-Narrative Review on Surgical Options for Recalcitrant Cases

PURPOSE

Lateral epicondylitis or lateral elbow tendinopathy is a common condition which needs to be addressed appropriately. This condition usually responds well to non-operative treatment. However, an orthopaedic physician needs to be aware of the recalcitrant cases and equip surgical armamentarium to provide adequate care.

METHODOLOGY

The literature search was performed on PubMed, Medline and Google scholar using the keywords Tennis elbow, recalcitrant, thorntons technique, surgical options, for this narrative review.

CONCLUSION

This article focuses on the causes for recalcitrant tendinopathy and review of its surgical options.

Leopoli-Cencelle (9th-15th centuries CE), a centre of Papal foundation: bioarchaeological analysis of the skeletal remains of its inhabitants

BACKGROUND

The medieval city of Leopoli-Cencelle (9th-15th centuries CE) represents an exceptional study-model for extending our knowledge of the Italian Medieval period due not only to the large sample size available but also to the widespread presence of material data and a well preserved archaeological context.

AIM

This research aims to reconstruct the osteobiography of the inhabitants of this centre of Papal foundation.

SUBJECTS AND METHODS

The analysed sample counts 877 individuals. Scientifically established anthropological morphological methods were used for assessing their biological profile as well as for reconstructing lifestyle and health status.

RESULTS

The sample consists of 62.49% adults and 37.51% non-adults. The mortality pattern shows the highest peak prior to 1 year and between 1 and 6 years of age and a reduced longevity of female individuals as commonly observed in pre-antibiotic era populations. Metric and musculoskeletal stress markers revealed different biomechanical stress between sexes probably carrying out different working activities. The palaeopathological analysis supports a general good health status with the exception of a few specific cases.

CONCLUSIONS

The present research helps shed light on the lifestyle of the inhabitants of Leopoli-Cencelle, enhancing a better understanding of the Italian Middle Ages.

Can platelet-rich plasma therapy save patients with ulnar collateral ligament tears from surgery?

Introduction

Platelet-rich plasma (PRP) has been shown to be effective in treating partial tears of the ulnar collateral ligament (UCL) of the elbow in overhead throwing athletes, but it is still unknown whether it has a role in complete tears. The aim of this study was to assess the effectiveness of PRP in treating complete as well as partial UCL tears. We hypothesized that trephination of the injured UCL followed by injection with PRP can promote healing of both partial and complete tears.

Methods

Thirty-four baseball players with partial or complete UCL tears confirmed by magnetic resonance imaging (MRI) were included in the study. They were all recalcitrant to more than two months of rest and physical therapy. Under ultrasound guidance, trephination of the UCL was performed using an 18-gauge needle, followed by PRP injection. Visual analog scale (VAS) scores, Disabilities of the Arm, Shoulder, and Hand (DASH) sports module scores, and sonographic ulnohumeral joint space measurements with valgus stress were all obtained prior to the procedure and six months after.

Results

Twenty-six of 30 athletes were able to return to sport with pre-injury level of play within six months after the procedure, at an average time of 12.4 weeks (range: 10-18). Four subjects needed surgical treatment for persistent UCL insufficiency. The average follow-up was 54.2 weeks (range: 26-148). The average VAS and DASH scores improved from 53.5 to 17.2 (p < 0.0001) and from 81.7 to 24.2 (p < 0.0001), respectively. The average ulnohumeral joint space opening with valgus stress decreased from 3.81 mm to 3.45 mm (p = 0.018). Subgroup analysis by injury location revealed that the average VAS score improved from 48.2 to 8.6 (p < 0.0001) and from 64.0 to 34.5 (p = 0.0023) in proximal and distal tears, respectively. The average DASH score improved from 83.8 to 17.8 (p = 0.0001) and from 77.5 to 36.7 (p < 0.0001) in proximal and distal tears, respectively. The average ulnohumeral joint space opening with valgus stress decreased from 3.64 to 3.21 mm (p = 0.003) and from 4.14 to 3.92 mm (p = 0.0023) in proximal and distal tears, respectively. There was one case with a proximal tear that needed surgical management for failure of treatment, while there were three cases needing surgery in those with distal tears.

Conclusion

Ultrasound-guided PRP injection following trephination can be an effective treatment option for both partial and complete UCL tears of the elbow, especially proximal tears. The use of this technique for complete UCL tears may allow more athletes to avoid surgery and enable them to return to play faster.

Aberrant TGF-β activation in bone tendon insertion induces enthesopathy-like disease

Enthesopathy is a disorder of bone, tendon, or ligament insertion. It represents one-fourth of all tendon-ligament diseases and is one of the most difficult tendon-ligament disorders to treat. Despite its high prevalence, the exact pathogenesis of this condition remains unknown. Here, we show that TGF-β was activated in both a semi-Achilles tendon transection (SMTS) mouse model and in a dorsiflexion immobilization (DI) mouse model of enthesopathy. High concentrations of active TGF-β recruited mesenchymal stromal stem cells (MSCs) and led to excessive vessel formation, bone deterioration, and fibrocartilage calcification. Transgenic expression of active TGF-β1 in bone also induced enthesopathy with a phenotype similar to that observed in SMTS and DI mice. Systemic inhibition of TGF-β activity by injection of 1D11, a TGF-β-neutralizing antibody, but not a vehicle antibody, attenuated the excessive vessel formation and restored uncoupled bone remodeling in SMTS mice. 1D11-treated SMTS fibrocartilage had increased proteoglycan and decreased collagen X and matrix metalloproteinase 13 expression relative to control antibody treatment. Notably, inducible knockout of the TGF-β type II receptor in mouse MSCs preserved the bone microarchitecture and fibrocartilage composition after SMTS relative to the WT littermate controls. Thus, elevated levels of active TGF-β in the enthesis bone marrow induce the initial pathological changes of enthesopathy, indicating that TGF-β inhibition could be a potential therapeutic strategy.

Tendon injuries: Basic science and new repair proposals

Tendons connect muscles to bones, ensuring joint movement. With advanced age, tendons become more prone to degeneration followed by injuries. Tendon repair often requires lengthy periods of rehabilitation, especially in elderly patients. Existing medical and surgical treatments often fail to regain full tendon function.

The development of novel treatment methods has been hampered due to limited understanding of basic tendon biology. Recently, it was discovered that tendons, similar to other mesenchymal tissues, contain tendon stem/progenitor cells (TSPCs) which possess the common stem cell properties.

The current strategies for enhancing tendon repair consist mainly of applying stem cells, growth factors, natural and artificial biomaterials alone or in combination. In this review, we summarise the basic biology of tendon tissues and provide an update on the latest repair proposals for tendon tears.

Cite this article: EFORT Open Rev 2017;2:332-342. DOI: 10.1302/2058-5241.2.160075

[Tendinopathies of the shoulder and elbow]

BACKGROUND

Tendinopathies of the shoulder and elbow joint are a common problem. According to the current state of knowledge tendinopathies can be separated into acute and chronic tendinitis as well as degenerative tendinosis.

ORIGIN

The causes of tendinopathy can be intrinsic, extrinsic or a combination of both. A false straining or overuse with repetitive microtrauma is often the cause. Particularly affected are tendons of the rotator cuff, the long biceps tendons and lower arm extensors.

TREATMENT

Priority is given to conservative appproaches for these disease processes. Following appropriate diagnostics the pain can be reduced and function can be improved by specific training. When conservative treatment is unsuccessful and in the presence of certain indications, a surgical approach should be considered. In these cases a structural damage of the tendon often already exists, which could have resulted from the tendinopathy. The structural damage must be considered as a separate entity and differentiated from the tendinopathy.

Cellular and Molecular Factors Influencing Tendon Repair

Tendons are complex connective tissues that transmit tensile forces between muscles and tendons. Tendon injuries are among the most common orthopedic problems with long-term disability as a frequent consequence due to prolonged healing time. Furthermore, the repair tissue is of inferior quality, predisposing patients to high rates of recurrence following initial injury. Coordinated cellular processes and biological factors under the influence of mechanical loading are involved in tendon healing and our understanding of these events lags behind other musculoskeletal tissues. Tendons are relatively hypocellular and hypovascular, with little or no intrinsic regenerative capacity. Studies have documented fatty degeneration, chondrogenic dysplasia, and ectopic ossification within tendon repair tissue. The underlying pathogenesis for these metaplastic changes that compromise the quality of tendon repair tissue is poorly understood. The purpose of this review is to compile literature reporting molecular processes that regulate/control the phenotype of cells responsible for abnormal matrix deposition at repair site. In addition, recent studies reporting the interplay of mechanotransduction and cellular responses during tendon repair are summarized. Identifying the links between cellular, biological, and mechanical parameters involved in tendon repair is paramount to develop successful therapies for tendon healing.

Sonoelastography of the Common Flexor Tendon of the Elbow with Histologic Agreement: A Cadaveric Study

Purpose To determine the correlation of the results of conventional B-mode ultrasonography (US) and compression sonoelastography with histologic results in common flexor tendons of the elbow in human cadavers. Materials and Methods Twenty-five common flexor tendons were evaluated in 16 fresh, unembalmed cadavers of 11 women with a median age of 85 years (range, 71-101 years) and five men with a median age of 78 years (range, 70-88 years). Informed consent was provided according to the last will of the donors. B-mode US results were classified as grade 1, normal tendon with homogeneous fibrillar pattern; grade 2, tendon thickening or hypoechoic areas and/or calcifications in less than 30% of the tendon; or grade 3, hypoechoic areas and/or calcifications greater than 30% of the tendon. Sonoelastographic results were grade 1, blue (hardest) to green (hard); grade 2, yellow (soft); and grade 3, red (softest). The intraclass correlation coefficient was calculated to determine agreement with histologic findings for each B-mode US, sonoelastographic, and combined B-mode US and sonoelastographic examination. Histologic results were grade 1, normal, with parallel fibrillar pattern; grade 2, mild tendinopathy, with cellular infiltration, angiogenesis, or fatty vacuoles; or grade 3, severe tendinopathy, with loss of parallel collagen structure and necrosis. Results Histologic alterations were detected in 44% (11 of 25) of biopsy specimens. Intraclass correlation with histologic results was 0.57 for B-mode US, 0.68 for sonoelastography, and 0.84 for the combination of the two approaches. Conclusion The addition of sonoelastography to B-mode US provided statistically significant improvement in correlation with histologic results compared with the use of B-mode US alone (P < .02). ^© RSNA, 2016 Online supplemental material is available for this article.

Structural and Ultrastructural Characteristics of Bone-Tendon Junction of the Calcaneal Tendon of Adult and Elderly Wistar Rats

Tendons are transition tissues that transfer the contractile forces generated by the muscles to the bones, allowing movement. The region where the tendon attaches to the bone is called bone-tendon junction or enthesis and may be classified as fibrous or fibrocartilaginous. This study aims to analyze the collagen fibers and the cells present in the bone-tendon junction using light microscopy and ultrastructural techniques as scanning electron microscopy and transmission electron microscopy. Forty male Wistar rats were used in the experiment, being 20 adult rats at 4 months-old and 20 elderly rats at 20 months-old. The hind limbs of the rats were removed, dissected and prepared to light microscopy, transmission electron microscopy and scanning electron microscopy. The aging process showed changes in the collagen fibrils, with a predominance of type III fibers in the elderly group, in addition to a decrease in the amount of the fibrocartilage cells, fewer and shorter cytoplasmic processes and a decreased synthetic capacity due to degradation of the organelles involved in synthesis.

Management of Lateral Elbow Tendinopathy: One Size Does Not Fit All

Synopsis Clear guidelines for the clinical management of individuals with lateral elbow tendinopathy (LET) are hampered by many proposed interventions and the condition's prognosis, ranging from immediate resolution of symptoms following simple advice in some patients to long-lasting problems, regardless of treatment, in others. This is compounded by our lack of understanding of the complexity of the underlying pathophysiology of LET. In this article, we collate evidence and expert opinion on the pathophysiology, clinical presentation, and differential diagnosis of LET. Factors that might provide prognostic value or direction for physical rehabilitation, such as the presence of neck pain, tendon tears, or central sensitization, are canvassed. Clinical recommendations for physical rehabilitation are provided, including the prescription of exercise and adjunctive physical therapy and pharmacotherapy. A preliminary algorithm, including targeted interventions, for the management of subgroups of patients with LET based on identified prognostic factors is proposed. Further research is needed to evaluate whether such an approach may lead to improved outcomes and more efficient resource allocation. J Orthop Sports Phys Ther 2015;45(11):938-949. Epub 17 Sep 2015. doi:10.2519/jospt.2015.5841.

Image-guided elbow interventions: a literature review of interventional treatment options

Over the years, a wide range of image-guided interventional therapies have been used in treating different elbow pathologies, many of which are predominantly based on anecdotal and low-level study findings. This article critically assesses the existing literature and discusses the efficacy of the most commonly utilized interventional procedures for elbow pathology.

The influence of life history and sexual dimorphism on entheseal changes in modern humans and African great apes

Entheseal changes have been widely studied with regard to their correlation to biomechanical stress and their usefulness for biocultural reconstructions. However, anthropological and medical studies have demonstrated the marked influence of both age and sex on the development of these features. Studies of entheseal changes are mostly aimed in testing functional hypotheses and are mostly focused on modern humans, with few data available for non-human primates. The lack of comparative studies on the effect of age and sex on entheseal changes represent a gap in our understanding of the evolutionary basis of both development and degeneration of the human musculoskeletal system. The aim of the present work is to compare age trajectories and patterns of sexual dimorphism in entheseal changes between modern humans and African great apes. To this end we analyzed 23 postcranial entheses in a human contemporary identified skeletal collection (N = 484) and compared the results with those obtained from the analysis of Pan (N = 50) and Gorilla (N = 47) skeletal specimens. Results highlight taxon-specific age trajectories possibly linked to differences in life history schedules and phyletic relationships. Robusticity trajectories separate Pan and modern humans from Gorilla, whereas enthesopathic patterns are unique in modern humans and possibly linked to their extended potential lifespan. Comparisons between sexes evidence a decreasing dimorphism in robusticity from Gorilla, to modern humans to Pan, which is likely linked to the role played by size, lifespan and physical activity on robusticity development. The present study confirms previous hypotheses on the possible relevance of EC in the study of life history, pointing moreover to their usefulness in evolutionary studies.

Prevalence and risk factors of lateral epicondylitis in a mountain village in Japan

PURPOSE

To determine the prevalence and risk factors of lateral epicondylitis in a mountain village in Japan.

METHODS

176 men and 246 women aged 24 to 86 (mean, 61) years from a mountain village in Japan underwent regular medical examination and completed a self-administered questionnaire with items related to gender, weight, height, dominant hand, heaviness of labour (no job, light, intermediate, and heavy), presence of elbow pain 2 weeks before examination, and smoking and drinking experience. The diagnosis of lateral epicondylitis was based on self-reported symptoms and clinical signs.

RESULTS

The prevalence of lateral epicondylitis in a mountain village in Japan was 3.8% (95% confidence interval [CI], 2.2%-6.1%). Of the 422 subjects, 47 had elbow pain and 16 of them were diagnosed to have definite lateral epicondylitis. 15 of them were right-handed and had involvement of the left (n=8) and right (n=7) sides; the remaining one was left-handed and had involvement of the left side. The dominant hand was not associated with the affected side (p=1.00). Heaviness of labour was not associated with the elbow pain scores. The prevalence was highest in subjects aged 50 to 59 years (9% [95% CI, 3.8%-17.1%]) and those with no job (14% [95% CI, 1.1%-44.1%]).

CONCLUSION

Lateral epicondylitis was not associated with gender, age, body mass index, dominant hand, heaviness of labour, smoking, or drinking.

The short-term effect after a single injection of high-molecular-weight hyaluronic acid in patients with enthesopathies (lateral epicondylitis, patellar tendinopathy, insertional Achilles tendinopathy, and plantar fasciitis): a preliminary study

BACKGROUND

Hyaluronic acid (HA) with a high molecular weight of 2700 kDa is approved in Japan to treat osteoarthritis of the knee, periarthritis scapulohumeralis, and knee pain associated with rheumatoid arthritis. The purpose of this preliminary study was to investigate the short-term efficacy, safety, and injectable volume of HA in the treatment of enthesopathies.

METHODS

A total of 61 patients (16 with lateral epicondylitis, 14 with patellar tendinopathy, 15 with insertional Achilles tendinopathy, and 16 with plantar fasciitis) were each administered a single injection of HA (up to 2.5 ml). Efficacy and safety were assessed by comparing the visual analog scale (VAS) for pain and local symptoms before injection (baseline) and at 1 week after injection. We also investigated the injectable volume by means of the difference in syringe weight before and after injection and by the judgment of the administering investigator.

RESULTS

The injection of HA resulted in a change in VAS (mean ± SD) of -2.20 ± 2.26 cm for the four sites overall and -2.55 ± 2.43 cm for lateral epicondylitis, -2.01 ± 2.16 cm for patellar tendinopathy, -1.80 ± 1.91 cm for insertional Achilles tendinopathy, and -2.38 ± 2.61 cm for plantar fasciitis. The injection of HA also improved local symptoms in each site. It was also determined that 2.5 ml of HA can be injected in each of the four sites.

CONCLUSION

A single injection of HA resulted in similar improvements of pain in each of the four enthesopathies (lateral epicondylitis, patellar tendinopathy, insertional Achilles tendinopathy, and plantar fasciitis). These results suggest that HA could be clinically effective in the treatment of enthesopathies.

Joint capsule attachment to the extensor carpi radialis brevis origin: an anatomical study with possible implications regarding the etiology of lateral epicondylitis

PURPOSE

To identify the unique anatomical characteristic of the extensor carpi radialis brevis (ECRB) origin and points of differentiation from other extensors and to clarify the specific relationship of the ECRB to the underlying structures.

METHODS

We studied the origin of each extensor macroscopically for its muscular and tendinous parts; to identify the relationship between the ECRB origin and the deeper structures, we also examined the attachment of the joint capsule under the ECRB origin.

RESULTS

The ECRB simply originated as a tendon without any muscle, whereas other extensors originated as a mixture of tendon and muscle. At the anterior part of the ECRB origin, the thin attachment of the joint capsule (average width, 3.3 mm) lay deep to the ECRB and was distinct. However, at the posterodistal portion, the joint capsule, annular ligament, and supinator were intermingled and originated as a single wide sheet from the humerus (average width, 10.7 mm).

CONCLUSIONS

The anterior part of the ECRB origin was delicate, because the ECRB origin was purely tendinous, and the attachment of the articular capsule was thin compared with that of the posterodistal attachment. This thin attachment could be an initial factor leading to the development of lateral epicondylitis.

CLINICAL RELEVANCE

The results of the current study may enhance magnetic resonance imaging understanding and may help clarify the etiology of the lateral epicondylitis.

Innervation pattern at the undersurface of the extensor carpi radialis brevis tendon in recalcitrant tennis elbow

PURPOSE

We investigated the general, sensory, and sympathetic innervation patterns at the undersurface of the extensor carpi radialis brevis (ECRB) origin in patients with recalcitrant tennis elbow.

METHODS

Eight elbows in eight consecutive patients (6 females and 2 males) with tennis elbow who underwent arthroscopic surgery were included in this study. The mean age was 45 years (38-66 years), and the mean duration of symptoms before surgery was 23 months (13-52 months). Operative treatment consisted of an arthroscopic inspection and debridement of the ECRB origin. Control tissues were obtained from biopsy of the ECRB capsule in two patients with osteochondritis dissecance of the capitellum who underwent arthroscopic resection of loose bodies. The tissue specimens were investigated immunohistochemically with antibodies delineating general (PGP9.5), sensory (SP/CGRP), and sympathetic (NPY) nerve patterns.

RESULTS

In the non-tendinosis control tissue, SP/CGRP and NPY immunoreactions were heterogeneously distributed in association with blood vessels. Pathologic evaluation of the biopsy tissue showed atypical fibrous granulation containing numerous vessels and nerve structures in all eight patients. Marked reactions to PGP 9.5 took the form of nerve fibers associated with arteries and arterioles in the atypical granulation. Most of the perivascular innervation was found to express NPY. The immunoreactions for SP and CGRP were invariably weak.

CONCLUSION

Increased perivascular sympathetic innervation accompanied with loss of sensory innervation at the undersurface of the ECRB tendon may play a role in chronic pain generation in recalcitrant tennis elbow.

LEVEL OF EVIDENCE

Diagnostic, Level IV.

Chronological changes in the collagen-type composition at tendon-bone interface in rabbits

Objectives

The purpose of this study was to evaluate chronological changes in the collagen-type composition at tendon–bone interface during tendon–bone healing and to clarify the continuity between Sharpey-like fibres and inner fibres of the tendon.

Methods

Male white rabbits were used to create an extra-articular bone–tendon graft model by grafting the extensor digitorum longus into a bone tunnel. Three rabbits were killed at two, four, eight, 12 and 26 weeks post-operatively. Elastica van Gieson staining was used to colour 5 µm coronal sections, which were examined under optical and polarised light microscopy. Immunostaining for type I, II and III collagen was also performed.

Results

Sharpey-like fibres comprised of type III collagen in the early phase were gradually replaced by type I collagen from 12 weeks onwards, until continuity between the Sharpey-like fibres and inner fibres of the tendon was achieved by 26 weeks.

Conclusions

Even in rabbits, which heal faster than humans, an observation period of at least 12 to 26 weeks is required, because the collagen-type composition of the Sharpey-like fibre bone–tendon connection may have insufficient pullout strength during this period. These results suggest that caution is necessary when permitting post-operative activity in humans who have undergone intra-bone tunnel grafts.

The aging athlete: part 2, "boomeritis" of the upper extremity

OBJECTIVE

The purpose of this review is to describe the upper extremity injuries that frequently accompany aging, the typical clinical presentations, and the differential diagnoses with an emphasis on the injury most likely encountered with each presentation.

CONCLUSION

Expectation of continued participation in exercise and sports activities by the baby boomer population has presented new challenges to the medical field. The concepts behind factors that predispose older athletes to certain pathologic conditions that affect the muscles, tendons, and bones of the upper extremity must be understood.

Fibrocartilage in various regions of the human glenoid labrum. An immunohistochemical study on human cadavers

PURPOSE

The nature and the distribution of fibrocartilage at the human glenoid labrum are unclear, and a better understanding may help to restore its function in open and arthroscopic Bankart repair. Aim of this study was to describe the fibrocartilage extent within the labrum at clinically relevant sites of the glenoid in order to relate the molecular composition of the labrum to its mechanical environment.

METHODS

Twelve fresh frozen human cadaveric shoulders (mean age 38 years) were obtained, and sections perpendicular to the glenoid rim at the 12, 2, 3, 4, 6 and 9 o' clock position were labelled with antibodies against collagen I and II, aggrecan and link protein.

RESULTS

A fibrocartilaginous transition zone with a characteristic collagen fibre orientation was found in 81% of cases, evenly distributed (83-92%) around the glenoid rim. The percentage of labrum cross-sectional area comprised of fibrocartilage averaged 28% and ranged from 26% at 12 o'clock on the glenoid clock face to 30% at 3 o'clock. The highest amount of fibrocartilage (82%) was found in the region neighbouring the hyaline articular cartilage. In the region beyond the bony edge of the glenoid, fibrocartilage cross-sectional area did not exceed 12-17%.

CONCLUSION

Fibrocartilage is present at all examined positions around the glenoid rim and constitutes up to 1/3 of the cross-sectional area of the labrum. In turn, the percentage of fibrocartilage in different regions of its cross-section varies considerably. The findings suggest that the penetration of fibrocartilaginous tissue may be reduced by avoiding the highly fibrocartilage transition zone during restoration of labral detachment.

The effect of age, sex, and physical activity on entheseal morphology in a contemporary Italian skeletal collection

Entheseal changes are traditionally included in a large array of skeletal features commonly referred to as "skeletal markers of activity." However, medical studies and recent anthropological analyses of identified skeletal series suggest a complex combination of physiological and biomechanical factors underlying the variability of such "markers." The aim of this study is to examine the relationship between age, sex, physical activity, and entheseal variability. To this end, 23 postcranial entheses are examined in a large (N = 484) Italian contemporary skeletal series using standardized scoring methods. The sample comprises subjects of known age, sex and, mostly, occupation. Results show a strong relationship between age and entheseal changes. Differences between sexes are also highlighted, while the effects of physical activity appear moderate. Altogether, our study indicates that entheseal morphology primarily reflects the age of an individual, while correlation with lifetime activity remains ambiguous.

Enthesopathies as occupational stress markers: evidence from the upper limb

Enthesopathies--that is, "musculo-skeletal stress markers"--are frequently used to reconstruct past lifestyles and activity patterns. Relatively little attention has been paid in physical anthropology to methodological gaps implicit in this approach: almost all methods previously employed neglect current medical insights into enthesopathies and the distinction between healthy and pathological aspects has been arbitrary. This study presents a new visual method of studying fibrocartilaginous enthesopathies of the upper limb (modified from Villotte: Bull Mém Soc Anthropol Paris n.s. 18 (2006) 65-85), and application of this method to 367 males who died between the 18th and 20th centuries, from four European identified skeletal collections: the Christ Church Spitalfields Collection, the identified skeletal collection of the anthropological museum of the University of Coimbra, and the Sassari and Bologna collections of the museum of Anthropology, University of Bologna. The analysis, using generalized estimating equations to model repeated binary outcome variables, has established a strong link between enthesopathies and physical activity: men with occupations involving heavy manual tasks have significantly (P-value < 0.001) more lesions of the upper limbs than nonmanual and light manual workers. Probability of the presence of an enthesopathy also increases with age and is higher for the right side compared with the left. Our study failed to distinguish significant differences between the collections when adjusted for the other effects. It appears that enthesopathies can be used to reconstruct past lifestyles of populations if physical anthropologists: 1) pay attention to the choice of entheses in their studies and 2) use appropriate methods.

Subsistence activities and the sexual division of labor in the European Upper Paleolithic and Mesolithic: evidence from upper limb enthesopathies

Studies of cultural artifacts and faunal remains from European Upper Paleolithic and Mesolithic sites indicate a shift in hunter gatherer subsistence strategies, involving an intensification and diversification of resource exploitation relative to earlier foragers during the Tardiglacial and Postglacial periods. This trend has been recognized as well through the analysis of non-pathological skeletal adaptations of the upper limbs of European Upper Paleolithic human fossils. These paleoanthropological studies of adaptive bone modeling also raise the question of female use of throwing-based weapon technology in the Upper Paleolithic. Here, we studied another type of osteological marker of activity, enthesopathies, of the upper limb remains of 37 European Upper Paleolithic and Mesolithic human fossils, with the goal of testing two hypotheses: 1) that activity levels were heightened at the end of Upper Paleolithic and into the Mesolithic relative to earlier foragers of the Gravettian, and 2) that there was an absence of a marked sexual division of labor in European hunter-gatherers during this time span. Our results are consistent with the first hypothesis; upper limb enthesopathies are significantly less frequent in the Gravettian group, but raise doubts about the second hypothesis. Four males exhibit lesions that can be confidently associated with throwing activities, while no females exhibit such lesions.

Can osseous landmarks in the distal medial humerus be used to identify the attachment sites of ligaments and tendons: paleopathologic-anatomic imaging study in cadavers

OBJECTIVE

To describe osseous landmarks that allow identification of the attachments of the ligaments and tendons in the distal medial aspect of the humerus.

MATERIALS AND METHODS

Reliable osseous landmarks in the distal medial aspect of the humerus were identified in 34 well-preserved specimens from a paleopathologic collection. These osseous landmarks were then sought in magnetic resonance (MR) images of ten cadaveric elbow specimens so that the ease of their visualization and optimal imaging plane could be assessed. To assign these osseous landmarks to specific attachments of the tendons and ligaments in the distal medial humerus, we cut the specimens in slices and photographed and examined them. Subsequently, the prevalence of these osseous landmarks as well as the attachment sites of the tendons and ligaments in this location was determined.

RESULTS

We determined ten reliable osseous landmarks in the distal medial aspect of the humerus, their prevalence and ease of identification, and their relationship to the attachments of the tendons and ligaments at the medial distal humerus.

CONCLUSION

It is possible to use osseous landmarks at the distal medial humerus to facilitate identification of the different attachments of tendons and ligaments when MR images of the elbow are assessed.

Magnetic resonance imaging of entheses. Part 1

Entheses are the sites of attachment of a tendon, ligament, or joint capsule to bone. Many features of entheses are adapted to disperse stress and accommodate compressive and shear forces at, or near, boundaries between tendons or ligaments and bone. Of particular interest is calcified and uncalcified fibrocartilage, which has mechanical properties that differ from those of tensile regions of tendons or ligaments, and from bone. Ultrashort echo time (UTE) pulse sequences can identify the specific tissue components of entheses and differentiate cortical bone, calcified fibrocartilage, uncalcified fibrocartilage, and fibrous connective tissue. Magic angle imaging can also differentiate tissues, such as fibrocartilage and tendon, which have different fibre orientations. Understanding the magnetic resonance (MR) appearance of entheses involves consideration of tissue properties, fibre-to-field angle, magic angle effects, pulse sequences, and geometrical factors including fibre-to-section orientation and partial volume effects. New approaches using MR imaging, allow entheses to be visualised with much greater detail than previously possible, and this may help in biomechanical studies, diagnosis of disease including overuse syndromes and spondyloarthropathies, as well as monitoring tissue repair and healing.

Arthroscopic, macroscopic, and microscopic anatomy of the synovial fold of the elbow joint in correlation with the common extensor origin

PURPOSE

The objective of our study was to clarify the arthroscopic, macroscopic, and microscopic anatomy of the radiocapitellar synovial fold of the elbow joint in correlation with the common extensor origin.

METHODS

We performed arthroscopy in 14 fresh-frozen cadaveric elbows and found the synovial fold covering the radial head or interposing in the radiocapitellar joint in 6. The fold was tagged with loop suture under arthroscopy to identify its exact location in gross anatomy. The radiocapitellar joint capsule was then resected without disturbing the continuity of the common extensor and lateral epicondyle. Macroscopic and histologic evaluation was performed for the lateral elbow capsular complex.

RESULTS

The synovial fold was found to be a triangular-shaped thickening of the capsule located on the proximal edge of the annular ligament. The mean distance between the lateral epicondyle and the base of the fold at the anterior edge, middle part, and posterior edge was 23 mm, 8 mm, and 13 mm, respectively. This structure was distinct from the annular ligament but was continuous with the radiocapitellar joint capsule. The joint capsule and the common extensor tendon blended with each other imperceptibly and formed a single enthesis at the lateral epicondyle.

CONCLUSIONS

The synovial fold identified by arthroscopy is a physiologic capsular tissue located on the proximal edge of the annular ligament. It is distinct from the annular ligament but has a close correlation with the common extensor tendon enthesis at the lateral epicondyle.

CLINICAL RELEVANCE

The synovial fold belongs to the lateral epicondyle enthesis, which is a composite of the common extensor tendon, undersurface capsule, and bone. Therefore, lateral epicondylitis with degenerative lesions in the area of the common extensor origin may involve the synovial fold and induce hypertrophic changes.

Tenocyte responses to mechanical loading in vivo: a role for local insulin-like growth factor 1 signaling in early tendinosis in rats

OBJECTIVE

To investigate tenocyte regulatory events during the development of overuse supraspinatus tendinosis in rats.

METHODS

Supraspinatus tendinosis was induced by running rats downhill at 1 km/hour for 1 hour a day. Tendons were harvested at 4, 8, 12, and 16 weeks and processed for brightfield, polarized light, or transmission electron microscopy. The development of tendinosis was assessed semiquantitatively using a modified Bonar histopathologic scale. Apoptosis and proliferation were examined using antibodies against fragmented DNA or proliferating cell nuclear antigen, respectively. Insulin-like growth factor 1 (IGF-1) expression was determined by computer-assisted quantification of immunohistochemical reaction. Local IGF-1 signaling was probed using antibodies to phosphorylated insulin receptor substrate 1 (IRS-1) and ERK-1/2.

RESULTS

Tendinosis was present after 12 weeks of downhill running and was characterized by tenocyte rounding and proliferation as well as by glycosaminoglycan accumulation and collagen fragmentation. The proliferation index was elevated in CD90+ tenocytes in association with tendinosis and correlated with increased local IGF-1 expression by tenocytes and phosphorylation of IRS-1 and ERK-1/2. Both apoptosis and cellular inflammation were absent at all time points.

CONCLUSION

In this animal model, early tendinosis was associated with local stimulation of tenocytes rather than with extrinsic inflammation or apoptosis. Our data suggest a role for IGF-1 in the load-induced tenocyte responses during the pathogenesis of overuse tendon disorders.

Inhibition of IL-1, IL-6, and TNF-alpha in immune-mediated inflammatory diseases

Blockade of cytokines, particularly of tumour necrosis factor alpha (TNF-alpha), in immuno-inflammatory diseases, has led to the greatest advances in medicine of recent years. We did a thorough review of the literature with a focus on inflammation models in rodents on modified gene expression or bioactivity for IL-1, IL-6, and TNF-alpha, and we summarized the results of randomized controlled clinical trials in human disease. What we have learned herewith is that important information can be achieved by the use of animal models in complex, immune-mediated diseases. However, a clear ranking for putative therapeutic targets appears difficult to obtain from an experimental approach alone. This is primarily due to the fact that none of the disease models has proven to cover more than one crucial pathogenetic aspect of the complex cascade of events leading to characteristic clinical disease signs and symptoms. This supports the notion that the addressed human immune-mediated diseases are polygenic and the summation of genetic, perhaps epigenetic, and environmental factors. Nevertheless, it has become apparent, so far, that TNF-alpha is of crucial importance in the development of antigen-dependent and antigen-independent models of inflammation, and that these results correlate well with clinical success. With some delay, clinical trials in conditions having some relationship with rheumatoid arthritis (RA) indicate new opportunities for blocking IL-1 or IL-6 therapeutically. It appears, therefore, that a translational approach with critical, mutual reflection of simultaneously performed experiments and clinical trials is important for rapid identification of new targets and development of novel treatment options in complex, immune-mediated, inflammatory diseases.

Where tendons and ligaments meet bone: attachment sites ('entheses') in relation to exercise and/or mechanical load

Entheses (insertion sites, osteotendinous junctions, osteoligamentous junctions) are sites of stress concentration at the region where tendons and ligaments attach to bone. Consequently, they are commonly subject to overuse injuries (enthesopathies) that are well documented in a number of sports. In this review, we focus on the structure-function correlations of entheses on both the hard and the soft tissue sides of the junction. Particular attention is paid to mechanical factors that influence form and function and thus to exploring the relationship between entheses and exercise. The molecular parameters indicative of adaptation to mechanical stress are evaluated, and the basis on which entheses are classified is explained. The application of the 'enthesis organ' concept (a collection of tissues adjacent to the enthesis itself, which jointly serve the common function of stress dissipation) to understanding enthesopathies is considered and novel roles of adipose tissue at entheses are reviewed. A distinction is made between different locations of fat at entheses, and possible functions include space-filling and proprioception. The basic anchorage role of entheses is considered in detail and comparisons are explored between entheses and other biological 'anchorage' sites. The ability of entheses for self-repair is emphasized and a range of enthesopathies common in sport are reviewed (e.g. tennis elbow, golfer's elbow, jumper's knee, plantar fasciitis and Achilles insertional tendinopathies). Attention is drawn to the degenerative, rather than inflammatory, nature of most enthesopathies in sport. The biomechanical factors contributing to the development of enthesopathies are reviewed and the importance of considering the muscle-tendon-bone unit as a whole is recognized. Bony spur formation is assessed in relation to other changes at entheses which parallel those in osteoarthritic synovial joints.

Biomechanische Eigenschaften von Gelenkknorpel nach hydrostatischer Hochdruckbehandlung Biomechanical properties of articular cartilage after high hydrostatic pressure treatment

AIM

Reconstruction of bone defects due to malignant tumors can be realized by several methods. Up to now, two methods, irradiation and autoclaving, are available for extracorporeally devitalizing resected tumor-bearing osteochondral segments. Previous investigations have shown that human normal and tumor cells in culture were irreversibly impaired when subjected to extracorporeal high hydrostatic pressure (HHP) of 350 MPa. The aim of this study was to examine the biomechanical and immunohistochemical properties of cartilage after exposure to HHP MATERIALS AND METHODS: Osteochondral segments of bovine femoral condyles were exposed to pressure of 300 and 600 MPa (n=20 each). Biomechanical and biological properties of untreated and treated segments were evaluated by repetitive ball indention testing and immunohistochemical labelling aggrecan, link protein and collagen II. The contralateral segments served as untreated control.

RESULTS

No significant alterations concerning stiffness and relaxation of osteochondral segments even after 600 MPa were observed. Immunohistochemically, staining was positive in all cases and no differences in the labeling pattern of proteoglycanes were observed between untreated and HHP-treated specimens.

CONCLUSION

These findings give hope that HHP eventually will be used as a new gentle way of treating resected cartilage and bone without alteration of biomechanical properties to inactivate tumor cells in order to allow autologous reimplantation.