Single nucleus and spatial transcriptomic profiling of healthy human hamstring tendon.

The molecular and cellular basis of health in human tendons remains poorly understood. Among human tendons, hamstring tendon has markedly low pathology and can provide a prototypic healthy tendon reference. The aim of this study was to determine the transcriptomes and location of all cell types in healthy hamstring tendon. Using single nucleus RNA sequencing, we profiled the transcriptomes of 10 533 nuclei from four healthy donors and identified 12 distinct cell types. We confirmed the presence of two fibroblast cell types, endothelial cells, mural cells, and immune cells, and identified cell types previously unreported in tendons, including different skeletal muscle cell types, satellite cells, adipocytes, and undefined nervous system cells. The location of these cell types within tendon was defined using spatial transcriptomics and imaging, and potential transcriptional networks and cell-cell interactions were analyzed. We demonstrate that fibroblasts have the highest number of potential cell-cell interactions in our dataset, are present throughout the tendon, and play an important role in the production and organization of extracellular matrix, thus confirming their role as key regulators of hamstring tendon homeostasis. Overall, our findings underscore the complexity of the cellular networks that underpin healthy human tendon function and the central role of fibroblasts as key regulators of hamstring tendon tissue homeostasis.

Proresolving Mediators LXB4 and RvE1 Regulate Inflammation in Stromal Cells from Patients with Shoulder Tendon Tears.

Tendon stromal cells isolated from patients with chronic shoulder rotator cuff tendon tears have dysregulated resolution responses. Current therapies do not address the biological processes concerned with persistent tendon inflammation; therefore, new therapeutic approaches that target tendon stromal cells are required. We examined whether two specialized proresolving mediators (SPMs), lipoxin B4 (LXB4) and resolvin E1 (RvE1), modulate the bioactive lipid mediator profiles of IL-1ß-stimulated tendon cells derived from patients with shoulder tendon tears and healthy volunteers. We also examined whether LXB4 or RvE1 treatments moderated the proinflammatory phenotype of tendon tear stromal cells. Incubation of IL-1ß-treated patient-derived tendon cells in LXB4 or RvE1 up-regulated concentrations of SPMs. RvE1 treatment of diseased tendon stromal cells increased 15-epi-LXB4 and regulated postaglandin F2α. LXB4 or RvE1 also induced expression of the SPM biosynthetic enzymes 12-lipoxygenase and 15-lipoxygenase. RvE1 treatment up-regulated the proresolving receptor human resolvin E1 compared with vehicle-treated cells. Incubation in LXB4 or RvE1 moderated the proinflammatory phenotype of patient-derived tendon tear cells, regulating markers of tendon inflammation, including podoplanin, CD90, phosphorylated signal transducer and activator of transcription 1, and IL-6. LXB4 and RvE1 counterregulate inflammatory processes in tendon stromal cells, supporting the role of these molecules as potential therapeutics to resolve tendon inflammation.

15-Epi-LXA4 and MaR1 counter inflammation in stromal cells from patients with Achilles tendinopathy and rupture.

Resolution of inflammation is poorly understood in Achilles tendon disorders. Herein, we investigated the bioactive lipid mediator profiles of tendon-derived stromal cells isolated from patients with Achilles tendinopathy (AT) or Achilles rupture (AR) under baseline and IL-1ß-stimulated conditions. We also determined whether incubating these cells with 2 of the mediators produced by tendon-derived stromal cells, 15-epi-Lipoxin A4 (15-epi-LXA4) or maresin (MaR)-1, moderated their proinflammatory phenotype. Under baseline conditions, AT cells showed concurrent increased levels of proinflammatory eicosanoids and proresolving mediators compared with AR cells. IL-1ß treatment induced profound prostaglandin E2 release in AR compared with AT cells. Incubation of IL-1ß treated AT and AR tendon-derived stromal cells in 15-epi-LXA4 or MaR1 reduced proinflammatory eicosanoids and potentiated the release of proresolving mediators. These mediators also induced specialized proresolving mediator (SPM) biosynthetic enzymes arachidonate lipoxygenase (ALOX) 12 and ALOX15 and up-regulated the proresolving receptor ALX compared with vehicle-treated cells. Incubation in 15-epi-LXA4 or MaR1 also moderated the proinflammatory phenotype of AT and AR cells, regulating podoplanin, CD90, signal transducer and activator of transcription (STAT)-1, IL-6, IFN regulatory factor (IRF) 5, and TLR4 and suppressed c-Jun N-terminal kinase 1/2/3, Lyn, STAT-3, and STAT-6 phosphokinase signaling. In summary, we identify proresolving mediators that are active in AT and AR and propose SPMs, including 15-epi-LXA4 or MaR1, as a potential strategy to counterregulate inflammatory processes in these cells.-Dakin, S. G., Colas, R. A., Newton, J., Gwilym, S., Jones, N., Reid, H. A. B., Wood, S., Appleton, L., Wheway, K., Watkins, B., Dalli, J., Carr, A. J. 15-Epi-LXA4 and MaR1 counter inflammation in stromal cells from patients with Achilles tendinopathy and rupture.

Arthroscopic subacromial decompression for subacromial shoulder pain (CSAW): a multicentre, pragmatic, parallel group, placebo-controlled, three-group, randomised surgical trial.

BACKGROUND: Arthroscopic sub-acromial decompression (decompressing the sub-acromial space by removing bone spurs and soft tissue arthroscopically) is a common surgery for subacromial shoulder pain, but its effectiveness is uncertain. We did a study to assess its effectiveness and to investigate the mechanism for surgical decompression. METHODS: We did a multicentre, randomised, pragmatic, parallel group, placebo-controlled, three-group trial at 32 hospitals in the UK with 51 surgeons. Participants were patients who had subacromial pain for at least 3 months with intact rotator cuff tendons, were eligible for arthroscopic surgery, and had previously completed a non-operative management programme that included exercise therapy and at least one steroid injection. Exclusion criteria included a full-thickness torn rotator cuff. We randomly assigned participants (1:1:1) to arthroscopic subacromial decompression, investigational arthroscopy only, or no treatment (attendance of one reassessment appointment with a specialist shoulder clinician 3 months after study entry, but no intervention). Arthroscopy only was a placebo as the essential surgical element (bone and soft tissue removal) was omitted. We did the randomisation with a computer-generated minimisation system. In the surgical intervention groups, patients were not told which type of surgery they were receiving (to ensure masking). Patients were followed up at 6 months and 1 year after randomisation; surgeons coordinated their waiting lists to schedule surgeries as close as possible to randomisation. The primary outcome was the Oxford Shoulder Score (0 [worst] to 48 [best]) at 6 months, analysed by intention to treat. The sample size calculation was based upon a target difference of 4·5 points (SD 9·0). This trial has been registered at ClinicalTrials.gov, number NCT01623011. FINDINGS: Between Sept 14, 2012, and June 16, 2015, we randomly assigned 313 patients to treatment groups (106 to decompression surgery, 103 to arthroscopy only, and 104 to no treatment). 24 [23%], 43 [42%], and 12 [12%] of the decompression, arthroscopy only, and no treatment groups, respectively, did not receive their assigned treatment by 6 months. At 6 months, data for the Oxford Shoulder Score were available for 90 patients assigned to decompression, 94 to arthroscopy, and 90 to no treatment. Mean Oxford Shoulder Score did not differ between the two surgical groups at 6 months (decompression mean 32·7 points [SD 11·6] vs arthroscopy mean 34·2 points [9·2]; mean difference -1·3 points (95% CI -3·9 to 1·3, p=0·3141). Both surgical groups showed a small benefit over no treatment (mean 29·4 points [SD 11·9], mean difference vs decompression 2·8 points [95% CI 0·5-5·2], p=0·0186; mean difference vs arthroscopy 4·2 [1·8-6·6], p=0·0014) but these differences were not clinically important. There were six study-related complications that were all frozen shoulders (in two patients in each group). INTERPRETATION: Surgical groups had better outcomes for shoulder pain and function compared with no treatment but this difference was not clinically important. Additionally, surgical decompression appeared to offer no extra benefit over arthroscopy only. The difference between the surgical groups and no treatment might be the result of, for instance, a placebo effect or postoperative physiotherapy. The findings question the value of this operation for these indications, and this should be communicated to patients during the shared treatment decision-making process. FUNDING: Arthritis Research UK, the National Institute for Health Research Biomedical Research Centre, and the Royal College of Surgeons (England).

Construct Validity and Precision of Different Patient-reported Outcome Measures During Recovery After Upper Extremity Fractures.

BACKGROUND: Patient perceptions of their limitations after illness and injury can be quantified using patient-reported outcome measures (PROMs). Few studies have assessed construct validity (using correlations and factor analysis) and precision (floor and ceiling effects) of a range of frequently used PROMs longitudinally in a population of patients recovering from common upper extremity fractures according to area (general health, region-specific, or joint-specific measures) and mode of administration (fixed-scale or computer adaptive test). QUESTIONS/PURPOSES: (1) What is the strength of the correlation between different PROMs within 1 week, 2 to 4 weeks and 6 to 9 months after shoulder, elbow, and wrist fractures? (2) Using a factor analysis, what underlying constructs are being measured by these PROMs? (3) Are there strong floor and ceiling effects with these instruments? METHODS: Between January 2016 and August 2016, 734 patients recovering from an isolated shoulder, elbow, or wrist fracture completed physical-limitation PROMs at baseline (the initial office visit after diagnosis in the emergency department), 2 to 4 weeks after injury, and at the final assessment 6 to 9 months after injury. In all, 775 patients were originally approached; 31 patients (4%) declined to participate due to time constraints, four patients died of unrelated illness, and six patients were lost to follow-up. The PROMs included the PROMIS Physical Function (PF, a computer adaptive, general measure of physical function), the PROMIS Upper Extremity (UE, a computer adaptive measure of upper extremity physical function), the QuickDASH (a fixed-scale, region-specific measure), the Oxford Shoulder Score (OSS), the Oxford Elbow Score (OES) and the Patient-rated Wrist Evaluation (PRWE) (a fixed-scale, joint-specific measure), and the EQ-5D-3L (a fixed-scale measure of general health). PROMs were evaluated during recovery for construct validity (using correlations and factor analysis) and precision (using floor and ceiling effects). RESULTS: Physical-limitation PROMs were intercorrelated at all time points, and the correlation strengthened over time (for example, PROMIS UE and QuickDASH at 1 week, r = -0.4665; at 2 to 4 weeks, r = -0.7763; at 6 to 9 months, r = -0.8326; p < 0.001). Factor analysis generated two factors or groupings of PROMs that could be described as capability (perceived ability to perform or engage in activities), and quality of life (an overall sense of health and wellbeing) that varied by time point and fracture type, Joint-specific and general-health PROMs demonstrated high ceiling effects 6 to 9 months after injury and PROMIS PF, PROMIS UE and QuickDASH had no floor or ceiling effects at any time points. CONCLUSIONS: There is a substantial correlation between PROMs that assess physical limitations (based on anatomic region) and general health after upper extremity fractures, and these relationships strengthen during recovery. Regardless of the delivery mode or area of focus, PROMs largely appear to represent two underlying constructs: capability and quality of life. Computer adaptive tests may be favored over fixed-scale measures for their efficiency and limited censoring. LEVEL OF EVIDENCE: Level II, therapeutic study.

Psychosocial factors affecting variation in patient-reported outcomes after elbow fractures.

BACKGROUND: The purpose of this study was to identify factors associated with limitations in function measured by patient-reported outcome measures (PROMs) 6-9 months after elbow fractures in adults from a range of demographic, injury, psychological, and social variables measured within a week and 2-4 weeks after injury. METHODS: We enrolled 191 adult patients sustaining an isolated elbow fracture and invited them to complete PROMs at their initial visit to the orthopedic outpatient clinic (within a maximum of 1 week after fracture), between 2 and 4 weeks, and between 6 and 9 months after injury; 183 patients completed the final assessment. Bivariate analysis was performed, followed by multivariable regression analysis accounting for multicollinearity. This was evaluated using partial R2, correlation matrices, and variable inflation factor assessment. RESULTS: There was a correlation between multiple variables within a week of injury and 2-4 weeks after injury with PROMs 6-9 months after injury in bivariate analysis. Kinesiophobia measured within a week of injury and self-efficacy measured at 2-4 weeks were the strongest predictors of limitations 6-9 months after injury in multivariable regression. Regression models accounted for substantial variance in all PROMs at both time points. CONCLUSIONS: Developing effective coping strategies to overcome fears related to movement and reinjury and finding ways of persevering with activity despite pain within a month of injury may enhance recovery after elbow fractures. Heightened fears around movement and suboptimal coping ability are modifiable using evidence-based behavioral treatments.

What Factors Are Associated With Disability After Upper Extremity Injuries? A Systematic Review.

BACKGROUND: Psychosocial factors are key determinants of health after upper extremity injuries. However, a systematic review is needed to understand which psychosocial factors are most consistently associated with disability and how the language, conceptualization, and types of measures used to assess disability impact these associations in upper extremity injuries. QUESTIONS/PURPOSES: (1) What factors are most consistently associated with disability after upper extremity injuries in adults? (2) What are the trends in types of outcome measures and conceptualization of disability in patients' upper extremity injuries? METHODS: We searched multiple electronic databases (PubMED, OVIDSP, PsycInfo, Google Scholar, ISI Web of Science) between January 1, 1996, and December 31, 2016, using terms related to the "upper extremity", "outcome measurement", and "impairment, psychological, social or symptomatic" variables. We included all studies involving adult patients with any musculoskeletal injury and excluded those that did not use patient-reported outcome measures. We identified and screened 9339 studies. Of these, we retained 41 studies that involved conditions ranging from fractures to soft tissue injuries in various regions of the arm. We conducted quality assessment using a 10-item validated checklist and a five-tier strength of evidence assessment. We used the Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) criteria and registered the review before performing our search (PROSPERO: CRD42017054048). None of the authors received any funding to perform this work. RESULTS: Disability after upper extremity injury was most consistently associated with depression (21 cohorts), catastrophic thinking (13 cohorts), anxiety (11 cohorts), pain self-efficacy (eight cohorts), and pain interference (seven cohorts). Social and demographic factors were also associated with disability. Measures of impairment such as ROM and injury severity were least associated with disability. There has been a gradual increase in use of region or condition-specific patient-reported outcome measures and measures of psychological, social, and symptomatic factors over a period since the introduction of the World Health Organization (WHO) International Classification of Functioning, Disability and Health (ICF) around 2000. Approximately 17% of studies (n = 454 of 2628) had instances of unclear, conflicting, or inappropriate terminology and 11% of studies (n = 257 of 2628) involved misrepresentations of outcome measures related to disability. CONCLUSIONS: Psychologic and social factors are most consistently associated with disability than factors related to impairment. Further research involving the assessment of depression, anxiety, and coping strategies in cohorts with specific injuries may support decision-making regarding the provision of emotional support and psychologic therapies during recovery. Using the WHO ICF framework to conceptualize disability is key in increasing strength of evidence and allowing accurate comparisons of research in this field. LEVEL OF EVIDENCE: Level IV, therapeutic study.

Chronic inflammation is a feature of Achilles tendinopathy and rupture.

BACKGROUND: Recent investigation of human tissue and cells from positional tendons such as the rotator cuff has clarified the importance of inflammation in the development and progression of tendon disease. These mechanisms remain poorly understood in disease of energy-storing tendons such as the Achilles. Using tissue biopsies from patients, we investigated if inflammation is a feature of Achilles tendinopathy and rupture. METHODS: We studied Achilles tendon biopsies from symptomatic patients with either mid-portion tendinopathy or rupture for evidence of abnormal inflammatory signatures. Tendon-derived stromal cells from healthy hamstring and diseased Achilles were cultured to determine the effects of cytokine treatment on expression of inflammatory markers. RESULTS: Tendinopathic and ruptured Achilles highly expressed CD14+ and CD68+ cells and showed a complex inflammation signature, involving NF-κB, interferon and STAT-6 activation pathways. Interferon markers IRF1 and IRF5 were highly expressed in tendinopathic samples. Achilles ruptures showed increased PTGS2 and interleukin-8 expression. Tendinopathic and ruptured Achilles tissues expressed stromal fibroblast activation markers podoplanin and CD106. Tendon cells isolated from diseased Achilles showed increased expression of pro-inflammatory and stromal fibroblast activation markers after cytokine stimulation compared with healthy hamstring tendon cells. CONCLUSIONS: Tissue and cells derived from tendinopathic and ruptured Achilles tendons show evidence of chronic (non-resolving) inflammation. The energy-storing Achilles shares common cellular and molecular inflammatory mechanisms with functionally distinct rotator cuff positional tendons. Differences seen in the profile of ruptured Achilles are likely to be attributable to a superimposed phase of acute inflammation and neo-vascularisation. Strategies that target chronic inflammation are of potential therapeutic benefit for patients with Achilles tendon disease.

Recovery of Comfort and Capability After Upper Extremity Fracture Is Predominantly Associated With Mindset: A Longitudinal Cohort From the United Kingdom.

OBJECTIVES: To determine the relative influence of mindset and fracture severity on 9-month recovery trajectories of pain and capability after upper extremity fractures. DESIGN: Secondary use of longitudinal data. SETTING: Single Level-1 trauma center in Oxford, United Kingdom. PATIENT SELECTION: English-speaking adults with isolated proximal humerus, elbow, or distal radius fracture managed operatively or nonoperatively were included, and those with multiple fractures or cognitive deficit were excluded. OUTCOME MEASURES AND COMPARISONS: Incapability (Quick-DASH) and pain intensity (11-point rating scale) were measured at baseline, 2-4 weeks, and 6-9 months after injury. Cluster analysis was used to identify statistical groupings of mindset (PROMIS Depression and Anxiety, Pain Catastrophizing Scale, and Tampa Scale for Kinesiophobia) and fracture severity (low/moderate/high based on OTA/AO classification). The recovery trajectories of incapability and pain intensity for each mindset grouping were assessed, accounting for various fracture-related aspects. RESULTS: Among 703 included patients (age 59 ± 21 years, 66% women, 16% high-energy injury), 4 statistical groupings with escalating levels of distress and unhelpful thoughts were identified (fracture severity was omitted considering it had no differentiating effect). Groups with less healthy mindset had a worse baseline incapability (group 2: ß = 4.1, 3: ß = 7.5, and 4: ß = 17) and pain intensity (group 3: ß = 0.70 and 4: ß = 1.4) (P < 0.01). Higher fracture severity (ß = 4.5), high-energy injury (ß = 4.0), and nerve palsy (ß = 8.1) were associated with worse baseline incapability (P < 0.01), and high-energy injury (ß = 0.62) and nerve palsy (ß = 0.76) with worse baseline pain intensity (P < 0.01). Groups 3 and 4 had a prolonged rate of recovery of incapability (ß = 1.3, ß = 7.0) and pain intensity (ß = 0.19, ß = 1.1) (P < 0.02). CONCLUSIONS: Patients with higher levels of unhelpful thinking and feelings of distress regarding symptoms experienced worse recovery of pain and incapability, with a higher effect size than fracture location, fracture severity, high-energy injury, and nerve palsy. These findings underline the importance of anticipating and addressing mental health concerns during recovery from injury. LEVEL OF EVIDENCE: Prognostic Level III. See Instructions for Authors for a complete description of levels of evidence.