Methods to analyse the long head of the biceps in the management of distal ruptures of the supraspinatus tendon. Part 1: the concept of the "biceps box": dynamic rotator interval approach. Incidence of lesions of the long head of the biceps tendon.

INTRODUCTION: The area encompassing the long head of the biceps (LHB) can be represented as a rectangular parallelepiped. This geometric view can be likened to a box, the "biceps box", where the sides are the extrinsic structures and the LHB is the intrinsic structure. Since these structures are mobile in relation to each other, a dynamic "biceps box" model can modify assessments of the LHB, in its healthy or pathological state, and make the therapeutic approach to treating LHB lesions less arbitrary. MATERIAL AND METHOD: In order to describe the different sides of the "biceps box", and to understand their possible physiological and pathological consequences, a literature review using PRISMA methodology was used. RESULTS: The supraspinatus (SSP) has expansions on its anterior aspect that project anteriorly and cross the coracohumeral ligament (CHL). The most functionally important expansion is the fasciculus obliquus, which extends perpendicular to the axis of the tendon fibers of the SSP, divides the CHL into a deep and a superficial layer, and terminates on the superficial aspect of the subscapularis. The humeral insertion of the SSP may be binary, making a bridge over the LHB, with a posterior branch inserting on the greater tuberosity and an anterior branch on the lesser tuberosity. The superior glenohumeral ligament (SGHL) has a twisted course, downward and forward, and ends at the proximal opening of the bicipital groove with a flap on which the LHB rests. The bicipital pulley is not an independent structure but an arciform structure resulting from the fusion of several tissues. DISCUSSION: The presence of structures linked together by common expansions in the 3 planes of space validates the relevance of a "biceps box" as a functional geometric model. The structure that acts as a crossroads through which all expansions pass is the CHL. An extrinsic SSP lesion can be compensated for by other "biceps box" structures, whereas an extrinsic SGHL lesion rarely exists without the presence of an intrinsic LHB lesion. The CHL constitutes a connective tissue crossed by a vasculonervous pedicle from the lateral pectoral nerve, which may explain some anterior shoulder pain attributed to the biceps. CONCLUSION: The LHB can be likened to an intrinsic structure contained in a box whose sides are made up of different interconnected stabilizing structures defining the extrinsic structures. The concept of a dynamic "biceps box" allows LHB lesions to be accurately classified, separating extrinsic and intrinsic lesions, and thus potentially modifying therapeutic approaches to the LHB. LEVEL OF EVIDENCE: IV; systematic review.

Musculoskeletal ultrasound assessment in pediatric knee hypermobility: a case control study.

BACKGROUND: While musculoskeletal ultrasound (MSUS) use in pediatric rheumatology is becoming more common, the majority of pediatric MSUS literature continues to focus on ultrasound findings in healthy children and juvenile idiopathic arthritis with little discussion of other musculoskeletal problems that may mimic arthritis such as joint hypermobility. Chronic joint pain related to hypermobility is a common referral to pediatric rheumatology clinics. Our aim is to describe the musculoskeletal ultrasound (MSUS) characteristics of the knee in a population with joint hypermobility and pain in comparison to control participants. METHODS: Participants were recruited into three groups for a case-control study. Case group participants had knee hypermobility and pain symptoms (H + P). Participants in one control group had knee hypermobility without pain symptoms (H-P), and participants in the other control group had no knee hypermobility or pain symptoms (NP). B-mode and Doppler MSUS images were obtained and scored for each knee. Descriptive statistics are used for demographic variables and MSUS findings. Regression analysis is used to evaluate risk of synovial effusion and higher synovial effusion/hypertrophy quantitative score. RESULTS: MSUS assessment was performed on 91 knees of 50 participants. H + P knees were more likely to have positive findings noted on MSUS (94% vs. 70% of H-P and 74% of NP knees, p = 0.043). Patellar tendon hyperemia was more common in H + P knees (52%, vs. 19% among H-P and 23% among NP, p = 0.025). Participants who reported taking scheduled non-steroidal anti-inflammatory drugs (NSAIDs) had an increased risk of synovial effusion (RR = 1.83, 95% CI = 1.07-2.30, p = 0.026) and a trend towards increased risk of a higher synovial effusion/hypertrophy quantitative score (RR = 1.77, 95% CI = 0.92-3.38, p = 0.086). CONCLUSIONS: While positive MSUS findings were frequent in all participants, patellar tendon hyperemia was more frequent in participants with knee hypermobility and pain symptoms. Additionally, reported use of NSAIDs was associated with an increased risk of synovial effusion and higher synovial effusion/hypertrophy quantitative score. Further study should assess correlation between tendon abnormalities and degree of pain symptoms as well as the effect of NSAIDs on MSUS findings.

Cell lineage tracing and functional assessment of supraspinatus tendon healing in an acute repair murine model.

Rotator cuff supraspinatus tendon injuries are common with high rates of anatomic failure after surgical repair. The purpose of the study was to define clinically relevant features of a mouse model of supraspinatus tendon injury to determine painful, functional, and structural outcomes; we further investigated two cell populations mediating healing using genetic lineage tracing after full detachment and repair of the supraspinatus tendon in mice. The pain was assessed using the mouse grimace scale and function by gait analysis and tensile testing. Histological and microCT analyses were used to determine enthesis/tendon and bone structure, respectively. Lineage tracing was carried out using inducible Cre lines for ScxCreERT2 (tendon cells) and αSMACreERT2 (myofibroblasts and mesenchymal progenitors). Mice only expressed pain transiently after surgery despite long-term impairment of functional and structural properties. Gait, tensile mechanical properties, and bone properties were significantly reduced after injury and repair. Lineage tracing showed relatively few Scx lin tendon cells while αSMA lin cells contributed strongly to scar formation. Despite surgical reattachment of healthy tendon, lineage tracing revealed poor preservation of supraspinatus tendon after acute injury and loss of tendon structure, suggesting that tendon degeneration is also a key impediment of successful rotator cuff repair. Scar formation after surgery is mediated largely by αSMA lin cells and results in permanently reduced functional and structural properties.

Advances in the Development of Anti-Adhesive Biomaterials for Tendon Repair Treatment.

BACKGROUND: Peritendinous adhesion that simultaneous with tendon healing link the healing tendon to the surrounding tissue. It results in functional disability, and has a significant adverse impact on health as well as social and economic development. METHODS: Based on a search in the PubMed and Web of Science database, the research articles were screened by their time, main idea, impact factor index, while the ones with no credibility were excluded. Afterwards, we go through the analysis of the reliability and characteristics of the results were further screened from selected articles. RESULTS: A total of 17 biomaterials used to evaluate the adhesion mechanism and the properties of the material were found. All of these biomaterials contained randomized controlled studies and detailed descriptions of surgical treatment that support the reliability of their results which indicates that biomaterials act as barriers to prevent the formation of adhesion, and most of them exhibit satisfactory biocompatibility, biodegradability or selective permeability. Moreover, a few had certain mechanical strength, anti-inflammatory, or carrier capacities. However, there still existed some defects, such as time, technology, clinical trials, material targeting and different measurement standards which also lowered the reliability of their results. CONCLUSION: In future, anti-adhesion biomaterials should focus on affordable raw materials with wide sources, and the production process should be simplified, in this way, the versatility and targeting of materials will be improved.

Impact of the T2-weighted axial oblique MRI sequence in the assessment of peroneal tendons.

AIM: To define the role of the T2-weighted axial oblique sequence for the magnetic resonance imaging (MRI) assessment of peroneal tendon pathologies. MATERIALS AND METHODS: Two radiologists interpreted 180 ankle MRI examinations using standard sequences alone and then in combination with an axial oblique sequence. The readers indicated how likely a peroneal pathology was present using a five-level confidence scale. Diagnostic confidence, interobserver agreement, and clinical correlation were compared. Changes in diagnosis were recorded. RESULTS: For both readers, the diagnostic confidence was significantly higher using the axial oblique sequence for tendinosis and inframalleolar tenosynovitis for both tendons and for peroneus brevis partial and longitudinal split tears (p<0.001). For reader 1, the diagnostic confidence was also higher using the axial oblique sequence for peroneus longus partial tears (p=0.007). Changes in diagnosis were seen for tendinosis and tenosynovitis of both tendons and for peroneus brevis partial and longitudinal split tears in 0.6-10.8% of cases. Inter-rater reliability was significantly higher with the axial oblique sequence for the diagnosis of tendinosis, inframalleolar tenosynovitis, and partial tear for both tendons, and for peroneus brevis longitudinal split tear. Amongst 105 examinations with clinical information, peroneal pathologies were most frequently diagnosed as present in cases with lateral symptoms (17% versus 14%) and absent in cases without lateral symptoms (92% versus 86%) on the axial oblique sequence. CONCLUSION: The axial oblique sequence for the assessment of peroneal tendons allows for higher diagnostic confidence, inter-rater reliability, and clinical correlation and can lead to changes in diagnosis.

Detection of Age-Related Changes in Tendon Molecular Composition by Raman Spectroscopy-Potential for Rapid, Non-Invasive Assessment of Susceptibility to Injury.

The lack of clinical detection tools at the molecular level hinders our progression in preventing age-related tendon pathologies. Raman spectroscopy can rapidly and non-invasively detect tissue molecular compositions and has great potential for in vivo applications. In biological tissues, a highly fluorescent background masks the Raman spectral features and is usually removed during data processing, but including this background could help age differentiation since fluorescence level in tendons increases with age. Therefore, we conducted a stepwise analysis of fluorescence and Raman combined spectra for better understanding of the chemical differences between young and old tendons. Spectra were collected from random locations of vacuum-dried young and old equine tendon samples (superficial digital flexor tendon (SDFT) and deep digital flexor tendon (DDFT), total n = 15) under identical instrumental settings. The fluorescence-Raman spectra showed an increase in old tendons as expected. Normalising the fluorescence-Raman spectra further indicated a potential change in intra-tendinous fluorophores as tendon ages. After fluorescence removal, the pure Raman spectra demonstrated between-group differences in CH2 bending (1450 cm-1) and various ring-structure and carbohydrate-associated bands (1000-1100 cm-1), possibly relating to a decline in cellular numbers and an accumulation of advanced glycation end products in old tendons. These results demonstrated that Raman spectroscopy can successfully detect age-related tendon molecular differences.

Quantitative Assessment of Tendon Hierarchical Structure by Combined Second Harmonic Generation and Immunofluorescence Microscopy.

Histological evaluation of healing tendons is primarily focused on monitoring restoration of longitudinal collagen alignment, although the elastic property of energy-storing flexor tendons is largely attributed to interfascicular sliding facilitated by the interfascicular matrix (IFM). The objectives of this study were to explore the utility of second harmonic generation (SHG) imaging to objectively assess cross-sectional tendon fascicle architecture, to combine SHG microscopy with elastin immunofluorescence to assess the ultrastructure of collagen and elastin in longitudinal and transverse sections, and lastly, to quantify changes in IFM elastin and fascicle collagen alignment of normal and collagenase-injured flexor tendons. Paraffin-embedded transverse and longitudinal histological sections (10-µm thickness) derived from normal and collagenase-injured (6- and 16-week time-points) equine superficial digital flexor tendons were de-paraffinized, treated with Tris EDTA at 80°C for epitope retrieval, and incubated with mouse monoclonal anti-elastin antibody (1:100 dilution) overnight. Anti-mouse IgG Alexa Flour 546 secondary antibody was applied, and sections were mounted with ProLong Gold reagent with 4',6-diamidino-2-phenylindole (DAPI). Nuclei (DAPI) and elastin (Alexa Fluor 546) signals were captured by using standard confocal imaging with 405 and 543 nm excitation wavelengths, respectively. The SHG signal was captured by using a tunable Ti:Sapphire laser tuned to 950 nm to visualize type I collagen. Quantitative measurements of fascicle cross-sectional area (CSA), IFM thickness in transverse SHG-DAPI merged z-stacks, fascicle/IFM elastin area fraction (%), and elastin-collagen alignment in longitudinal SHG-elastin merged z-stacks were conducted by using ImageJ software. Using this methodology, fascicle CSA, IFM thickness, and IFM elastin area fraction (%) at 6 weeks (∼2.25-fold; ∼2.8-fold; 60% decrease; p < 0.001) and 16 weeks (∼2-fold; ∼1.5-fold; 70% decrease; p < 0.001) after collagenase injection, respectively, were found to be significantly different from normal tendon. IFM elastin and fascicle collagen alignment characterized via fast Fourier transform (FFT) frequency plots at 16 weeks demonstrated that collagen re-alignment was more advanced than that of elastin. The integration of SHG-derived quantitative measurements in transverse and longitudinal tendon sections supports comprehensive assessment of tendon structure. Our findings demonstrate the importance of including IFM and non-collagenous proteins in tendon histological evaluations, tasks that can be effectively carried out by using SHG and immunofluorescence microscopy. Impact statement This work demonstrated that second harmonic generation microscopy in conjunction with elastin immunofluorescence provided a comprehensive assessment of multiscale structural re-organization in healing tendon than when restricted to longitudinal collagen fiber alignment alone. Utilizing this approach for tendon histomorphometry is ideal not only to improve our understanding of hierarchical structural changes that occur after tendon injury and during remodeling but also to monitor the efficacy of therapeutic approaches.

Enthesitis in psoriatic arthritis (Part 3): clinical assessment and management.

Enthesitis is a common clinical feature of PsA, which is characterized by inflammation at the site of insertion of tendons, ligaments and joint capsule fibres into bone. Enthesitis is relatively unique to the spondyloarthritides, setting this group of diseases apart from other rheumatological conditions. The pathophysiological underpinnings of this clinical domain, and the imaging assessment of it, are described in accompanying articles in this supplement. The focus of this article is on the assessment of enthesitis by physical examination, the impact of enthesitis on function and quality of life, the impact of concomitant FM on clinical assessment, and the evidence for therapy of enthesitis garnered in trials of biologic and targeted synthetic DMARDs. Several physical examination measures of enthesitis have been developed and have proved reliable in assessment of enthesitis. Enthesitis has a significant deleterious impact on function and quality of life. The presence of concomitant FM in ≤20% of patients may result in artefactual worsening of assessment of disease severity and hinder achievement of the goal of low disease activity or remission. Several targeted therapies, which, for example, target the TNF, IL-17, IL-23, phosphodiesterase 4 or Janus kinase pathways, have shown significant efficacy in the treatment of enthesitis, resulting in improvement of function and quality of life for patients with PsA.

Reliable Reference Genes for Gene Expression Assessment in Tendon-Derived Cells under Inflammatory and Pro-Fibrotic/Healing Stimuli.

Tendon cells (TCs) are important for homeostatic maintenance in the healthy tendon and to promote tissue healing after injury. Further, resident and rare populations of tendon stem/progenitor cells, located at various sites within the tendon, contribute to tendon recovery by differentiating into repairing TCs. Gene expression analysis, through quantitative reverse-transcription polymerase chain reaction (qRT-PCR), constitutes a useful tool to study cellular responses, including the transition from initial inflammation to healing processes. A critical step required for data normalization is the choice of reliable reference genes (RGs), a process highly underestimated in tendon biology. In this study, the suitability of five commonly used RGs (ACTB, B2M, GAPDH, HPRT1, and RPLP0) was evaluated using TCs samples cultured in both standard and progenitor-enriching conditions, as well as under either inflammatory (IFNγ + TNFα) or pro-fibrotic/healing (CTGF) stimulation. The stability of the candidate RGs was computationally determined using NormFinder, geNorm, BestKeeper, and DeltaCt applets. Overall, ACTB resulted as the most stable RG on the basis of the integration of each gene weight, whereas B2M and RPLP0 performed poorly. To further validate ACTB's optimal performance, we evaluated the expression of ICAM1, coding for an immune-related cell surface glycoprotein, and COL1A1, encoding collagen type I that is the main component of the tendon extracellular matrix (ECM), both known to be modulated by inflammation. The expression of both genes was heavily affected by the RGs used. Consequently, when analyzing gene expression in tendon-derived cells subjected to various stimulatory protocols, the use of a suitable RG should be considered carefully. On the basis of our results, ACTB can be reliably used when analyzing different TC types exposed to pathological conditions.

Ultrasonographic assessment of quadriceps and patellar tendon thicknesses in patients with patellofemoral pain syndrome.

OBJECTIVE: The aim of this study was to compare ultrasonographically measured quadriceps and patellar tendon thicknesses between Patellofemoral Pain Syndrome (PFPS) patients and age- and gender-matched healthy controls. METHODS: Among patients who presented to physical therapy and rehabilitation outpatient clinic in January-December 2016, 61 volunteers (28 men and 33 women; mean age: 30.79 ± 6.55 years) who were eligible considering the inclusion and exclusion criteria were enrolled. 30 were diagnosed with PFPS, and the remaining were age- and gender-matched healthy volunteers. Mean age was 30.03 ± 5.67 years in healthy subjects and 45.2% were of male gender. The patient group had mean age of 31.57 ± 7.37 years and 46.7% of the patients were male. Q angles were measured at standing, supine and sitting positions. Patellar and femoral tendon thicknesses and areas were measured ultrasonographically. Kujala questionnaire were used to evaluate the functional status of the participants. RESULTS: No significant difference was detected between groups regarding profession, educational background, and body mass indices (BMI) (p > 0.05). Q angle values were significantly higher in the patient group when compared to controls at standing (17.03 ± 3.84 vs. 13.87 ± 1.75°, p < 0.001), supine (16.20 ± 3.74 vs. 13.45 ± 1.79°, p = 0.001) and sitting (16.50 ± 3.28 vs. 13.71 ± 1.72°, p < 0.001) positions. Kujala score was significantly lower in the PFPS group when compared to controls (70.57 ± 8.37 vs. 98.58 ± 2.05, p < 0.001). Patellar (0.39 ± 0.08 vs. 0.32 ± 0.05 cm, p < 0.001) and quadriceps (0.64 ± 0.10 vs. 0.52 ± 0.09 cm, p < 0.001) tendon thicknesses were significantly higher in the PFPS group when compared to controls. There was no significant difference between groups regarding patellar tendon areas (p > 0.05). Patellar tendon thickness values of ≥0.35 cm were found to have 66.7% sensitivity and 67.7% specificity for PFPS diagnosis in the ROC curve analysis (area under curve: 0.771, 95% confidence interval: 0.655-0.887, p < 0.001). Quadriceps tendon thickness values of ≥0.54 cm were found to have 80% sensitivity and 71% specificity for PFPS diagnosis in the ROC curve analysis (area under curve: 0.824, 95% confidence interval: 0.710-0.939, p < 0.001). In PFPS patients, quadriceps tendon thickness had significant positive correlation with age (r = 0.405, p = 0.027) and BMI (r = 0.450, p = 0.013); and significant negative correlation with Kujala score (r = -0.441, p = 0.015). In the multivariate regression analysis, quadriceps tendon thickness was independently associated with the presence of PFPS (Exp (B): 3.089, 95% confidence interval: 1.344-7.100, p = 0.008). CONCLUSION: Our study demonstrates that ultrasonographically measured patellar and quadriceps tendon thicknesses are significantly higher in subjects with PFPS and particularly, quadriceps tendon thickness may be used for the diagnosis. LEVEL OF EVIDENCE: Level III, Therapeutic Study.

Ultrasound in the assessment of musculoskeletal involvement in systemic lupus erythematosus: state of the art and perspectives.

Musculoskeletal manifestations are extremely common in patients with systemic lupus erythematosus. Transient and migratory arthralgia is frequently reported even without clinical signs of joint or tendon inflammation. In less than 15% of patients, joints may be more severely affected by deforming (Jaccoud's arthropathy) and/or erosive arthropathy (Rhupus syndrome). In recent years, ultrasound has emerged as a promising imaging technique for the assessment of musculoskeletal involvement in systemic lupus erythematosus, having demonstrated the ability to detect inflammation and structural damage both at articular and periarticular level. Recent ultrasound studies have also revealed new insights into musculoskeletal involvement in patients with systemic lupus erythematosus, some of them questioning the traditional concepts of systemic lupus erythematosus arthropathy, with potential clinical, prognostic and therapeutic implications. In daily clinical practice, the use of ultrasound in the assessment of joint and tendon involvement in patients with systemic lupus erythematosus is still limited. Several methodological issues encountered in ultrasound studies evaluating musculoskeletal involvement in systemic lupus erythematosus patients need to be addressed in order to improve both the reliability and clinical usefulness of ultrasound findings. This paper reviews ultrasound studies assessing musculoskeletal involvement in patients with systemic lupus erythematosus, highlighting certainty, limits, potential applications and future perspectives of ultrasound use in systemic lupus erythematosus patients.

Histological assessment of a septum in the first dorsal compartment: a fresh cadaver study.

Resistance of de Quervain's disease to conservative treatment has been associated with an intertendinous septum in the first compartment; little is known about the histological features of such a septum. This study aimed to examine the intertendinous septum histologically and note its variations. After dissecting the first extensor compartment of 24 hands from 12 fresh frozen cadavers, the presence of any intertendinous septa was determined. The length of the extensor retinaculum and intertendinous septum was measured; histological findings of the first compartment with or without septa were studied and compared with those of the third/fourth compartment. Intertendinous septa were observed in 12 of 24 wrists. Histological assessment of the intertendinous septum revealed tissue similar in composition to the retinaculum observed between the third and fourth compartments.

Assessment of Muscle Wasting in Long-Stay ICU Patients Using a New Ultrasound Protocol.

There is currently no standardized procedure to assess sarcopenia in long-stay catabolic patients. Our aim is to analyze a novel ultrasound muscle assessment protocol in these patients versus healthy controls, by carrying out a prospective observational study. We designed a new ultrasound protocol that assesses quadriceps rectus femoris (QRF) muscle quality in real-time B-mode, color-Doppler, and M-mode ultrasound, and evaluates QRF intramuscular central tendon thickness, cross-sectional area, and muscle thickness in ultrasound B-mode. Logistic regression was performed as a multivariable analysis on 29 cases and 19 controls. The QRF muscle area and thickness were shown to significantly decrease (p ≤ 0.001), and the central tendon thickness significantly increased (p = 0.047) in cases versus controls. The QRF muscle echogenicity and angiogenic activity fasciculations, subcutaneous edema, and intramuscular fluid were also significantly different between the two groups (p < 0.001). The selected variables in the multivariate logit analysis were the muscle area (OR per cm² = 0.07; 95% confidence interval (CI) = 0.012⁻0.41) and the central tendon thickness (OR per mm 1.887; 95% CI = 2.66⁻13.38).

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.

Physical examination tests and imaging studies based on arthroscopic assessment of the long head of biceps tendon are invalid.

PURPOSE: The aim of this study was to evaluate whether glenohumeral arthroscopy is an appropriate gold standard for the diagnosis of long head of biceps (LHB) tendon pathology. The objectives were to evaluate whether the length of tendon that can be seen at arthroscopy allows visualisation of areas of predilection of pathology and also to determine the rates of missed diagnoses at arthroscopy when compared to an open approach. METHODS: A systematic review of cadaveric and clinical studies was performed. The search strategy was applied to MEDLINE, PubMed and Google Scholar databases. All relevant articles were included. Critical appraisal of clinical studies was performed using a validated quality assessment scale. RESULTS: Five articles were identified for inclusion in the review. This included both clinical and cadaveric studies. The overall population comprised 18 cadaveric specimens and 575 patients. Out of the five included studies, three reported the length of LHB tendon visualised during arthroscopy and four reported the rate of missed LHB diagnosis. Cadaveric studies showed that the use of a hook probe allowed arthroscopic visualisation of between 34 and 48 % of the overall length of the LHB. In the clinical series, the rate of missed diagnoses at arthroscopy when compared to open exploration ranged between 33 and 49 %. CONCLUSIONS: Arthroscopy allows visualisation of only a small part of the extra-articular LHB tendon. This leads to a high rate of missed pathology in the distal part of the tendon. Published figures for sensitivities and specificities of common physical examination and imaging tests for LHB pathology that are based on arthroscopy as the gold standard are therefore invalid. In clinical practice, it is important to note that a "negative" arthroscopic assessment does not exclude a lesion of the LHB tendon as this technique does not allow visualisation of common sites of distal pathology. LEVEL OF EVIDENCE: IV.

In vitro and in vivo assessment of magnetically actuated biomaterials and prospects in tendon healing.

AIM: To expand our understanding on the effect of magnetically actuated biomaterials in stem cells, inflammation and fibrous tissue growth. MATERIALS & METHODS: Magnetic biomaterials were obtained by doping iron oxide particles into starch poly-ϵ-caprolactone (SPCL) to create two formulations, magSPCL-1.8 and 3.6. Stem cell behavior was assessed in vitro and the inflammatory response, subcutaneously in Wistar rats. RESULTS: Metabolic activity and proliferation increased significantly overtime in SPCL and magSPCL-1.8. Electromagnetic fields attenuated the presence of mast cells and macrophages in tissues surrounding SPCL and magSPCL-1.8, between weeks 1 and 9. Macrophage reduction was more pronounced for magSPCL-1.8, which could explain why this material prevented growth of fibrous tissue overtime. CONCLUSION: Magnetically actuated biomaterials have potential to modulate inflammation and the growth of fibrous tissue.

Evaluating changes in tendon crimp with fatigue loading as an ex vivo structural assessment of tendon damage.

The complex structure of tendons relates to their mechanical properties. Previous research has associated the waviness of collagen fibers (crimp) during quasi-static tensile loading to tensile mechanical properties, but less is known about the role of fatigue loading on crimp properties. In this study (IACUC approved), mouse patellar tendons were fatigue loaded while an integrated plane polariscope simultaneously assessed crimp properties. We demonstrate a novel structural mechanism whereby tendon crimp amplitude and frequency are altered with fatigue loading. In particular, fatigue loading increased the crimp amplitude across the tendon width and length, and these structural alterations were shown to be both region and load dependent. The change in crimp amplitude was strongly correlated to mechanical tissue laxity (defined as the ratio of displacement and gauge length relative to the first cycle of fatigue loading assessed at constant load throughout testing), at all loads and regions evaluated. Together, this study highlights the role of fatigue loading on tendon crimp properties as a function of load applied and region evaluated, and offers an additional structural mechanism for mechanical alterations that may lead to ultimate tendon failure.

High-resolution MRI assessment of dactylitis in psoriatic arthritis shows flexor tendon pulley and sheath-related enthesitis.

OBJECTIVE: Dactylitis is a hallmark of psoriatic arthritis (PsA) where flexor tenosynovitis is common. This study explored the microanatomical basis of dactylitis using high-resolution MRI (hrMRI) to visualise the small entheses around the digits. METHODS: Twelve patients with psoriatic dactylitis (4 fingers, 8 toes), and 10 healthy volunteers (6 fingers, 4 toes) had hrMRI of the digits using a 'microscopy' coil and contrast enhancement. All structures were evaluated including the tendons and ligaments, related enthesis organs, pulleys, volar/plantar plates and tendon sheaths. RESULTS: In dactylitis, collateral ligament enthesitis was seen in nine digits (75%), extensor tendon enthesitis in six digits (50%), functional enthesitis (5 digits, 42%), abnormal enhancement at the volar plates (2/5 joints, 40%) and the plantar plate (1/5 joints, 20%). Nine cases (75%) demonstrated flexor tenosynovitis, with flexor tendon pulley/flexor sheath microenthesopathy observed in 50% of all cases. Less abnormalities which were milder was observed in the normal controls, none of whom had any signal changes in the tendon pulleys or fibrous sheaths. CONCLUSIONS: This study provides proof of concept for a link between dactylitis and 'digital polyenthesitis' including disease of the miniature enthesis pulleys of the flexor tendons, further affirming the concept of enthesitis in PsA.

Ultrasound composite scores for the assessment of inflammatory and structural pathologies in Psoriatic Arthritis (PsASon-Score).

INTRODUCTION: This study was performed to develop ultrasound composite scores for the assessment of inflammatory and structural lesions in Psoriatic Arthritis (PsA). METHODS: We performed a prospective study on 83 PsA patients undergoing two study visits scheduled 6 months apart. B-mode and Power Doppler (PD) findings were semi-quantitatively scored at 68 joints (evaluating synovia, perisynovial tissue, tendons and bone) and 14 entheses. We constructed bilateral and unilateral (focusing the dominant site) ultrasound composite scores selecting relevant sites by a hierarchical approach. We tested convergent construct validity, reliability and feasibility of inflammatory and structural elements of the scores as well as sensitivity to change for inflammatory items. RESULTS: The bilateral score (termed PsASon22) included 22 joints (6 metacarpophalangeal joints (MCPs), 4 proximal interphalangeal joints (PIPs) of hands (H-PIPs), 2 metatarsophalangeal joints (MTPs), 4 distal interphalangeal joints (DIPs) of hands (H-DIPs), 2 DIPs of feet (F-DIPs), 4 large joints) and 4 entheses (bilateral assessment of lateral epicondyle and distal patellar tendon). The unilateral score (PsASon13) compromised 13 joints (2 MCPs, 3 H-PIPs, 1 PIP of feet (F-PIP), 2 MTPs, 1 H-DIP and 2 F-DIPs and 2 large joints) and 2 entheses (unilateral lateral epicondyle and distal patellar tendon). Both composite scores revealed a moderate to high sensitivity (bilateral composite score 43% to 100%, unilateral 36% to 100%) to detect inflammatory and structural lesions compared to the 68-joint/14-entheses score. The inflammatory and structural components of the composite scores correlated weakly with clinical markers of disease activity (corrcoeffs 0 to 0.40) and the health assessment questionnaire (HAQ, corrcoeffs 0 to 0.39), respectively. Patients with active disease achieving remission at follow-up yielded greater reductions of ultrasound inflammatory scores than those with stable clinical activity (Cohen's d effect size ranging from 0 to 0.79). Inter-rater reliability of bi- and unilateral composite scores was moderate to good with ICCs ranging from 0.42 to 0.96 and from 0.36 to 0.71, respectively for inflammatory and structural sub-scores. The PsASon22 and PsASon13 required 16 to 26 and 9 to 13 minutes, respectively to be completed. CONCLUSION: Both new PsA ultrasound composite scores (PsASon22 and PsASon13) revealed sufficient convergent construct validity, sensitivity to change, reliability and feasibility.

Update on the surgical management of temporomandibular joint-centered tendon sheath giant cell tumor with intradural extension: introducing a cost-effective method in using temporal bone for skull base reconstruction in preventing brain hernia.

Tendon sheath giant cell tumor is an idiopathic proliferative and destructive disease of the synovium. It is rare and tends to arise in large joints, for example, knee and ankle, but it can also arise in temporomandibular joints (TMJs). Because of its destructive nature, immediate treatment upon diagnosis is recommended. Radical resection proved to be an excellent choice for superior local control. However, the unfavorable anatomic location of TMJ and infratemporal fossa tumor with intradural extension make such a resection impractical. Hereby, we reported a case of resection of a TMJ tendon sheath giant cell tumor with intradural extension using a transcranial approach. This involves a complex radical resection with subsequent reconstruction. Transposition of temporal bone flap is a novel state-of-the-art technique in reconstructing the middle fossa floor defect by providing a three-dimensional rigid architecture to support the brain. Temporal bone flap is a reliable plug for rigid support in preventing brain hernia and cerebrospinal fluid leak. Despite its complexity, this cost-effective technique is relatively straightforward to learn and is applicable across all socioeconomic groups.