Discoid Lateral Meniscus.

PURPOSE OF REVIEW: Discoid lateral meniscus (DLM) is a well-known meniscus variant, and comprises excess and thickened meniscal tissue, altered collagen ultrastructure, and peripheral instability. This article presents a comprehensive review on current knowledge of DLM, focusing on pathology in parallel with surgical techniques and outcomes. RECENT FINDINGS: A paradigm shift in surgical management of DLM is taking place as knee surgeons are seeing more patients with long-term sequelae of partial lateral meniscectomy, the standard treatment for DLM for many years. Surgical treatment has evolved alongside the understanding of DLM pathology. A new classification system has been proposed and optimal surgical techniques described in recent years. This article highlights up-to-date evidence and techniques in management of both acute DLM tears and joint restoration following subtotal meniscectomy for DLM. Surgical management of DLM must be tailored to individual pathology, which is variable within the diagnosis of DLM. We present an algorithm for management of DLM and discuss future directions for the understanding and treatment of this debilitating condition.

Frozen shoulder.

Frozen shoulder is a common debilitating disorder characterized by shoulder pain and progressive loss of shoulder movement. Frozen shoulder is frequently associated with other systemic conditions or occurs following periods of immobilization, and has a protracted clinical course, which can be frustrating for patients as well as health-care professionals. Frozen shoulder is characterized by fibroproliferative tissue fibrosis, whereby fibroblasts, producing predominantly type I and type III collagen, transform into myofibroblasts (a smooth muscle phenotype), which is accompanied by inflammation, neoangiogenesis and neoinnervation, resulting in shoulder capsular fibrotic contractures and the associated clinical stiffness. Diagnosis is heavily based on physical examination and can be difficult depending on the stage of disease or if concomitant shoulder pathology is present. Management consists of physiotherapy, therapeutic modalities such as steroid injections, anti-inflammatory medications, hydrodilation and surgical interventions; however, their effectiveness remains unclear. Facilitating translational science should aid in development of novel therapies to improve outcomes among individuals with this debilitating condition.

Quality assurance for the NHS abdominal aortic aneurysm screening programme in England.

INTRODUCTION: The National Health Service Abdominal Aortic Aneurysm Screening Programme (NAAASP) was introduced in England in 2009 to offer ultrasound screening to men over 65 years, in order to reduce aneurysm-related deaths. This study describes the development of a quality assurance (QA) process and conducts an analysis of the first round of QA visit reports. The aim was to identify themes where local providers can target their efforts for improvement. METHODS: Forty-one providers were assessed over 4 years using a process of QA visits adapted from previously established screening programmes. A mixture of qualitative and quantitative methods was used to analyse the 41 QA reports, which identified a range of recommendations for providers. The data were coded for key words and assigned to themes. The number of recommendations per visit report was compared with experience of the providers and performance against national screening standards. RESULTS: A total of 773 recommendations were made, with an average of 19 per QA visit. Around one third of the recommendations were based on governance and leadership standards, with 43.0 per cent of those based around commissioning and accountability. A significant relationship was seen between number of infrastructure recommendations and performance against standards. CONCLUSION: This review of a QA cycle found that sound infrastructure is key to the success of a local provider.

Stay Ipsilateral: An Analysis of Tibial Tunnel Distance Between Cruciate Ligament Reconstruction and Posterior Meniscal Root Repair.

PURPOSE: To establish mean distance or identify intersection between tibial tunnels for posterior meniscal root repair in the setting of anterior cruciate ligament (ACL) or posterior cruciate ligament (PCL) reconstruction. METHODS: Twelve cadaver knees and 12 solid foam synthetic tibiae were used. ACL and PCL tunnels were drilled for single-bundle reconstruction, and both medial and lateral posterior root repair tunnels were drilled. Specimens underwent computed tomography scanning and shortest distances between tunnels in all planes were measured by 2 readers. Distances were compared between groups using a t-test. RESULTS: In ACL reconstruction, the medial meniscal root tunnel was not significantly closer to the cruciate tunnel when drilled from either medial or lateral side (P = .333). The lateral meniscal root tunnel was significantly closer when drilled from medial compared to lateral side (P < .001). In PCL reconstruction, both medial (P = .037) and lateral (P = .028) meniscal root tunnels were significantly closer to the PCL tunnel when drilled from the contralateral side of the tibia. CONCLUSION: This study demonstrates that posterior meniscal root repair tunnels are often placed within a few millimeters and can even intersect cruciate ligament reconstruction tunnels in the proximal tibia. CLINICAL RELEVANCE: The information in this study may assist surgeons in planning for cruciate ligament reconstruction with concomitant posterior meniscal root repair.

Effect of Patient Height and Sex on the Patellar Tendon and Anterior Cruciate Ligament.

BACKGROUND: Graft-tunnel mismatch is an avoidable complication in anterior cruciate ligament (ACL) reconstruction. Patient height and sex may be predictors of patellar tendon length (PTL) and intra-articular ACL length (IAL). Understanding these relationships may assist in reducing graft-tunnel mismatch during ACL reconstruction with bone-patellar tendon-bone (BTB) autograft. PURPOSE: To determine the association of patient height and sex with PTL and IAL. STUDY DESIGN: Cross-sectional study; Level of evidence, 3. METHODS: Magnetic resonance imaging (MRI) studies were obtained on the healthy knees of 100 male and 100 female patients. Patients with prior surgery, open physes, significant degenerative changes, ACL rupture, or extensor mechanism injury were excluded. Three independent readers measured PTL, IAL, and Caton-Deschamps Index (CDI) on MRI. Bivariate and linear regression analysis was performed to detect the association of anthropometric data with anatomic parameters measured on MRI studies. RESULTS: The mean age and body mass index were not significantly different between the male and female patients; however, male patients were significantly taller than female patients (1.75 vs 1.72 m, respectively; P < .001). There was a substantial agreement between the 3 readers for all parameters (κ > 0.75). Overall, female patients had significantly longer PTL (47.38 vs 43.92 mm), higher CDI (1.146 vs 1.071), and shorter IAL (33.05 vs 34.39 mm) (P < .001 for all). Results of the linear regression analysis demonstrated that both height and female sex were predictive of longer PTL. Further, height was independently predictive of IAL but sex was not. CONCLUSION: PTL was correlated more with patient sex than height. IAL was also correlated with patient sex. Longer BTB grafts are expected to be harvested in female patients compared with male patients of the same height despite shorter IAL. These associations should be considered during BTB ACL reconstruction to minimize graft-tunnel mismatch.

The incidence and pattern of iliopsoas tendinitis following hip arthroscopy.

BACKGROUND: Iliopsoas tendinitis is a known source of extra-articular hip pain and it has been shown to be a common cause of continued hip pain following total hip arthroplasty. While iliopsoas tendinitis after hip arthroscopy is a well-known phenomenon amongst hip arthroscopists, its presentation, course, and treatment has yet to be elucidated. METHODS: An IRB-approved chart review was performed of patients undergoing hip arthroscopy for femoroacetabular impingement (FAI) between March 2015 and July 2017. No cases of dysplasia were included. All patients had combined cam/pincer impingement as well as labral pathology. Tendinitis patients were identified. Patient demographics, surgical data, time to onset/diagnosis of iliopsoas tendinitis, treatment (oral anti-inflammatories, corticosteroid injection, physical therapy), and resolution of symptoms were recorded. These cases were age- and sex-matched to a control group that did not develop postoperative iliopsoas tendinitis for comparison. Patient outcomes were measured with the modified Harris Hip Score (mHHS) and Nonarthritic Hip Score (NAHS) recorded from the preoperative and 1-year postoperative visits. RESULTS: Of 258 hip arthroscopy cases, 18 cases (7.0%) of postoperative iliopsoas tendinitis were diagnosed under high resolution ultrasound. On average, iliopsoas tendinitis was diagnosed 2.8 ± 1.8 months after surgery. There were no significant differences in age, sex, and BMI between patients that developed IP tendinitis compared to those that did not. No specific procedures were found to be significantly associated with incidence of postoperative IP tendinitis, including capsular closure.18 patients were treated with corticosteroid injection, which provided mild to moderate improvement for 5 (27.8%) patients and completely resolved symptoms for 13 patients (72.2%). Of all 18 patients with postoperative iliopsoas tendinitis confirmed by response to a diagnostic injection, 10 (55.6%) had symptoms improve within 3 months of diagnosis, 2 (11.1%) between 3 and 6 months, 4 (22.2%) between 6 and 12 months, and 2 (11.1%) after 1 year. No patients went on to have surgery for this problem. Patients with iliopsoas tendinitis had lower MHHS (p = 0.04) and NAHS (p = 0.09) scores at their 1-year postoperative visits. CONCLUSIONS: Iliopsoas tendinitis is a common source of pain following arthroscopic hip surgery and can be effectively diagnosed and treated with ultrasound-guided injection. Therefore, surgeons performing arthroscopic procedures of the hip must remain aware of and include it in their differential when encountering patients with hip flexion pain after surgery. Research should be continued to further evaluate the long-term outcomes and return to sport rates of these patients.

MRI of superior capsular reconstruction graft and associated short-term clinical outcomes in patients with massive irreparable rotator cuff tears.

OBJECTIVE: To assess MRI appearance of the dermal allograft and its correlation with clinical outcome following superior capsular reconstruction (SCR). MATERIALS AND METHODS: This is a retrospective study of patients who underwent SCR between 2015 and 2018. Patients with postoperative MRI and clinical follow-up were included. Exclusion criteria were preoperative shoulder instability, advanced glenohumeral arthritis, and lack of postoperative MRI or clinical follow-up. Radiographs and MRIs were evaluated for graft integrity and position, acromiohumeral interval, superior subluxation distance (SSD), and glenohumeral cartilage loss. Correlation between imaging and clinical outcome measures were assessed. RESULTS: 24 shoulders (23 patients) met the inclusion criteria at a mean clinical and MRI follow-up of 9.1 months. There were 12 intact grafts (50%) and 12 torn grafts (50%), most commonly at the glenoid attachment (8/12). Patients with graft tear had greater SSD (mean 10.5 ± 6.1 mm) than those without tear (mean 6.1 ± 3.8 mm) (p = 0.028). SSD > 7.9 mm had a 79% sensitivity and 91% specificity for graft tear. The intact grafts were more commonly covering the superior humeral head (91.7%) compared with the torn grafts (41.7%) (p = 0.027). There was improvement of clinical outcome measures including American Shoulder and Elbow Surgeons score (p = 0.005) and forward elevation (p = 0.021) although there was no correlation between clinical outcome and integrity of the graft. CONCLUSION: SCR results in significant short-term clinical improvement even in the presence of graft tear on postoperative MRIs on current study. Gap between graft and the anchors, non-superior position of the graft, and humeral head superior subluxation can be associated with tear.

Characterizing cam-type hip impingement in professional women's ice hockey players.

OBJECTIVE: There is a high prevalence of femoroacetabular impingement (FAI) amongst elite men's ice hockey players, yet little is known about the hips of players in the National Women's Hockey League (NWHL). The primary purpose of this study was to determine the prevalence of radiographic cam-type FAI in women's professional ice hockey players. The secondary purpose was to analyze the relationship between the cam deformity and both menarchal age and hip range-of-motion (ROM). METHODS: Data were collected for NWHL players during pre-participation physicals. Alpha angles were measured on 45° Dunn radiographs, with alpha angles >55° defined as cam-positive. Pearson correlation coefficients (ρ) were performed to analyze the relationship between alpha angle and both ROM measurements and menarchal age, with statistical significance set at p < 0.05. RESULTS: Twenty-six athletes were included. Twenty-four (92%) had alpha angles >55°; 20 players (77%) had bilateral cam deformity. Average menarchal age was 13.8 ± 1.7 years. There was a significant association between age of menarche and alpha angle (ρ = 0.36, p < 0.02). There was no significant association between alpha angle and hip ROM (p > 0.05). CONCLUSION: Elite women's ice hockey players have a higher prevalence of cam-type morphology than the general population. The positive association between alpha angle and menarchal age lends additional support to the etiological hypothesis of the cam lesion resulting from activity-related stress at the proximal femoral physis during skeletal development. Professional women's ice hockey players have a high risk of developing cam-type morphology, although each player's menarchal age may mediate her individual risk for cam development.

Collagen-Based Bioinductive Implant for Treatment of Partial Thickness Rotator Cuff Tears.

INTRODUCTION: Partial thicknessrotator cuff tears(PTRCT) have low healing potential and tend to progress over time if not addressed surgically. There is a relative paucity of literature discussing optimal treatment for symptomatic PTRCT as compared to full thicknessrotator cuff tears. The available data supports a treatment course of debridement with or without acromioplasty for symptomatic patients with tears less than 50% in thickness combined with the use of repair (conversion to full thickness or transtendinous) for symptomatic patients with tears greater than 50% in thickness. The aim of this study was to evaluate functional and radiographic outcomes following surgical implantation of a collagen-based bioinductive implant for PTRCT. METHODS: Patients with PTRCT who underwent implantation of a collagen-based bioinductive implant over the bursal surface of the rotator cuff were identified. Patients who had an implant placed to augment a standard full thickness repair were excluded from analysis. We administered questionnaires to patients with a minimum of 6 months since surgery and collected patient data including demographics, preoperative and postoperative American Shoulder and Elbow Society (ASES) scores, preoperative and postoperative visual analog scale (VAS) pain scores, complications, and satisfaction level. Magnetic resonance imaging (MRI) was obtained as needed, at 6 months, or at 12 months postoperatively, and tendon thickness was measured on coronal views. RESULTS: Thirty patients were identified who met the inclusion and exclusion criteria. Twenty-four patients (80% response rate) were available for follow-up; 19 were male and five were female. Mean age and body mass index were 54.5 ± 11.6 years and 28.6 ± 5.9 kg/m2 , respectively. Mean tear thickness as measured intraoperatively was 56.6%. There were 16 (66.7%) articular-sided, five (20.8%) bursal-sided, and three (12.5%) intrasubstance tears. Mean survey follow-up time was 19.1 months. Mean ASES scores increased significantly from 45.6 preoperatively to 68.1 postoperatively (p = 0.001). Mean VAS pain scores decreased significantly from 8.3 preoperatively to 3.8 postoperatively (p < 0.001). Mean patient satisfaction level was 7.5. Ten patients had both a preoperative and postoperative MRI available for comparison. Tendon thickness at the tear site increased significantly from 5.7 mm preoperatively to 6.5 mm at mean 9.9 months follow-up (p = 0.007). There were no implant-related complications. One patient suffered a traumatic re-tear 4 months postoperatively. CONCLUSION: Highly porous collagen-based bioinductive implants are safe and effective forreducing pain and improving shoulderfunction in patientswith PTRCT of approximately 50%, with radiographic evidence of new tissue formation. Randomized controlled trials are needed to assess efficacy relative to debridement and standard repair techniques.

Outcomes of Preoperative Opioid Usage in Hip Arthroscopy: A Comparison With Opioid-Naïve Patients.

PURPOSE: To compare postoperative outcomes between opioid-naïve patients and patients with a history of preoperative opioid usage undergoing hip arthroscopy. The secondary purpose is to determine whether preoperative opioid users consumed more oral morphine milligram equivalents than opioid-naïve patients following surgery. METHODS: This is a single-center, retrospective analysis comparing outcomes and postoperative opioid usage between patients with and without a history of preoperative opioid use. Inclusion criteria included patients ≥18 years, Tönnis grade 0 or 1, imaging consistent with FAI or labral pathology, and a diagnosis of symptomatic FAI requiring hip arthroscopy. Patient outcomes were compared throughout a 2-year follow-up using the modified Harris Hip Score, Nonarthritic Hip Score, and visual analog scale (VAS). RESULTS: In total, 17 patients were evaluated in each cohort. The mean age of the study cohort and control cohort were 52.0 ± 9.4 years and 51.2 ± 12.2 years, respectively. Female patients were 58.8% (n = 10) of both cohorts. Non-naïve patients had a lower preoperative Nonarthritic Hip Score (P = .05) and a greater VAS at their 6-month and 1-year (P < .001) postoperative visits. Naïve patients reported greater modified Harris Hip Scores 2 years postoperatively (P < .001). The study cohort was prescribed greater levels of oral morphine equivalents at the postoperative 1-year visit (P = .05). Opioid-naïve patients were more likely to reach minimally clinically important difference and patient acceptable symptom state of VAS at a faster rate. At the 2-year follow-up, 11.8% of opioid-naïve patients continued to take opioids compared with 58.8% from the non-naïve group for persistent hip pain (P < .001). CONCLUSIONS: We determined that preoperative opioid usage in patients undergoing hip arthroscopy is associated with inferior outcomes compared with opioid-naïve patients. In addition, preoperative opioid users are likely to continue the use of opioid medications postoperatively and at greater doses than opioid-naïve patients. LEVEL OF EVIDENCE: 3, retrospective comparative study.

Expanding Indications for Meniscal Repair.

Meniscus surgery has dramatically changed over the last 20 years. This article reviews the advances and current evidence in meniscus repair.

Clinical Outcomes of Hip Arthroscopy in Patients With Systemic Inflammatory Diseases Compared With Matched Controls at a Minimum of 2-Year Follow-Up.

PURPOSE: To evaluate postoperative outcomes and preoperative risk factors for patients with underlying systemic inflammatory disorders after hip arthroscopy. METHODS: A retrospective analysis of patients who had undergone hip arthroscopy, with a history of systemic inflammatory disease, was performed. This included patients with a diagnosis of lupus, a positive antinuclear antibody test, rheumatoid arthritis, psoriatic arthritis, sarcoidosis, inflammatory bowel disease, Reiter syndrome, and mixed connective tissue disease. These cases were 1:2 matched to a control group of patients with no history of systemic inflammatory disease based on age and sex. An a priori power analysis was conducted and A 1:2 case-control ratio was selected to increase study power. Inclusion criteria included all skeletally mature patients with hip pain refractory to nonoperative management who underwent hip arthroscopy for labral tears and femoroacetabular impingement. Skeletally immature patients, those with Tönnis grades of 2 or more (less than 2 mm of joint space), hip dysplasia, patients undergoing revision hip arthroscopy, and patients whose pain failed to improve after intra-articular injection were excluded. The primary outcome was rate of revision hip arthroscopy or total hip arthroplasty 24 months after surgery. Secondary outcomes included 2 patient-reported outcome scores, the modified Harris Hip Score (mHHS) and Non-Arthritic Hip Score (NAHS). RESULTS: Twenty patients (21 hip arthroscopy procedures) and 42 controls were included. There was no significant difference in proportion of patients who met failure criteria (28.6% vs 16.7%, P = .271) or 2-year survivorship (76.2% vs 83.3%, P = .496) between the systemic inflammatory disorder and control groups, respectively. Both groups had a significant improvement in mHHS and NAHS at 24 months compared with baseline; however, there was no significant difference in mHHS (P = .28) or NAHS (P = .22) at 24 months between the 2 groups. CONCLUSIONS: Patients with underlying inflammatory conditions have similar 2-year outcomes after hip arthroscopy for intra-articular pathology compared with patients with no history of inflammatory disease. LEVEL OF EVIDENCE: III, retrospective comparative study.

Patient-Centered Care: Total Hip Arthroplasty for Displaced Femoral Neck Fracture Does Not Increase Infection Risk.

INTRODUCTION: Total hip arthroplasty (THA) is often used for displaced femoral neck fracture. In this study, institutional hip arthroplasty data were compared with the National American College of Surgeons National Surgical Quality Improvement Program (NSQIP) data for any differences in outcomes between our hospital, with an integrated hip fracture care pathway, and those of the country as a whole. METHODS: Elective THA was compared with arthroplasty performed for acute fracture. Outcomes for both groups included thromboembolic event (VTE), death, and deep prosthetic infection. RESULTS: Institutional data revealed no increased rate of infection after THA for fracture compared with elective. National Surgical Quality Improvement Program analysis revealed higher infection rates in fracture arthroplasty. There was an increased VTE rate in fracture performed for arthroplasty compared with elective in both institutional and NSQIP data. CONCLUSIONS: When performed at an academic medical center with an integrated care program, THA for fracture can have similar infection rates to elective THA. By contrast, national data showed significantly higher rates of infection and VTE for arthroplasty for fracture compared with elective. The contrast in complication rates may be related to well-functioning comprehensive interdisciplinary pathways. Patient-centered care pathways may be optimal for hip fracture patients.

The Effects of Body Mass Index on Pain Control With Liposomal Bupivacaine in Hip and Knee Arthroplasty.

BACKGROUND: There is evidence to suggest that liposomal bupivacaine (LB) is an effective component of a multimodal pain regimen for total joint arthroplasty (TJA). Obesity has been associated with chronic pain following TJA. This study assessed whether early postoperative pain is affected by body mass index (BMI), and whether the standard LB dose has similar effects on obese vs nonobese patients. METHODS: A retrospective analysis of 2629 primary TJA over a 12-month period was conducted, with LB used in half of this group. Patients were further classified as nonobese (BMI < 30) or obese (BMI ≥ 30). Pain scores and narcotic use were recorded. Independent-sample t-tests were used for continuous variables and chi-squared analyses for categorical variables. A multivariate regression analysis was performed. RESULTS: Significantly less narcotic was required on postoperative days (POD) 0 and 1 in patients receiving LB compared to those who did not in both obese and nonobese patient groups. On POD 2, obese and nonobese patients had an increase in narcotic requirement, which was significant in obese patients. A regression analysis found that on POD 0 and POD 1, lack of LB use, obesity, and younger age were independently associated with increased narcotic use. CONCLUSION: While narcotic requirement of obese and nonobese patients decreased on POD 0 and POD 1 with initiation of LB at our institution, all patients demonstrated increased narcotic requirement on POD 2 which was statistically and clinically significant in obese patients. Further studies are needed to determine the optimal pain regimen in the growing obese population undergoing TJA.

IL-17A mediates inflammatory and tissue remodelling events in early human tendinopathy.

Increasingly, inflammatory mediators are considered crucial to the onset and perpetuation of tendinopathy. We sought evidence of interleukin 17A (IL-17A) expression in early human tendinopathy and thereafter, explored mechanisms whereby IL-17A mediated inflammation and tissue remodeling in human tenocytes. Torn supraspinatus tendon (established pathology) and matched intact subscapularis tendon (representing 'early pathology') along with control biopsies were collected from patients undergoing shoulder surgery. Markers of inflammation and IL-17A were quantified by RT-PCR and immunohistochemistry. Human tendon cells were derived from hamstring tendon obtained during ACL reconstruction. In vitro effects of IL-17A upon tenocytes were measured using RT-PCR, multiplex cytokine assays, apoptotic proteomic profiling, immunohistochemistry and annexin V FACS staining. Increased expression of IL-17A was detected in 'early tendinopathy' compared to both matched samples and non-matched control samples (p < 0.01) by RT-PCR and immunostaining. Double immunofluoresence staining revealed IL-17A expression in leukocyte subsets including mast cells, macrophages and T cells. IL-17A treated tenocytes exhibited increased production of proinflammatory cytokines (p < 0.001), altered matrix regulation (p < 0.01) with increased Collagen type III and increased expression of several apoptosis related factors. We propose IL-17A as an inflammatory mediator within the early tendinopathy processes thus providing novel therapeutic approaches in the management of tendon disorders.

MicroRNA29a regulates IL-33-mediated tissue remodelling in tendon disease.

MicroRNA (miRNA) has the potential for cross-regulation and functional integration of discrete biological processes during complex physiological events. Utilizing the common human condition tendinopathy as a model system to explore the cross-regulation of immediate inflammation and matrix synthesis by miRNA we observed that elevated IL-33 expression is a characteristic of early tendinopathy. Using in vitro tenocyte cultures and in vivo models of tendon damage, we demonstrate that such IL-33 expression plays a pivotal role in the transition from type 1 to type 3 collagen (Col3) synthesis and thus early tendon remodelling. Both IL-33 effector function, via its decoy receptor sST2, and Col3 synthesis are regulated by miRNA29a. Downregulation of miRNA29a in human tenocytes is sufficient to induce an increase in Col3 expression. These data provide a molecular mechanism of miRNA-mediated integration of the early pathophysiologic events that facilitate tissue remodelling in human tendon after injury.

IL-21 receptor expression in human tendinopathy.

The pathogenetic mechanisms underlying tendinopathy remain unclear, with much debate as to whether inflammation or degradation has the prominent role. Increasing evidence points toward an early inflammatory infiltrate and associated inflammatory cytokine production in human and animal models of tendon disease. The IL-21/IL-21R axis is a proinflammatory cytokine complex that has been associated with chronic inflammatory diseases including rheumatoid arthritis and inflammatory bowel disease. This project aimed to investigate the role and expression of the cytokine/receptor pair IL-21/IL-21R in human tendinopathy. We found significantly elevated expression of IL-21 receptor message and protein in human tendon samples but found no convincing evidence of the presence of IL-21 at message or protein level. The level of expression of IL-21R message/protein in human tenocytes was significantly upregulated by proinflammatory cytokines (TNFα/IL-1ß) in vitro. These findings demonstrate that IL-21R is present in early human tendinopathy mainly expressed by tenocytes and macrophages. Despite a lack of IL-21 expression, these data again suggest that early tendinopathy has an inflammatory/cytokine phenotype, which may provide novel translational targets in the treatment of tendinopathy.

Superficial wound closure complications with barbed sutures following knee arthroplasty.

As quality measures may be increasingly used in knee surgery reimbursement, an important focus in outcome assessment will shift toward minimizing complications and increasing efficiency in knee arthroplasty reconstruction. The purpose of this study was to evaluate the efficacy of barbed, absorbable sutures in closure of the longitudinal surgical incision following knee arthroplasty, using post-operative complication occurrences. In 416 operations, primary outcomes assessed were deep infection, superficial infection, dehiscence, or stitch abscesses. Secondary outcomes included self-limiting eschar, severe effusion, arthrofibrosis, and keloid formation. Evaluation of overall primary outcomes showed a higher rate of wound complications using barbed sutures (P < 0.001). With increased rates of infection and overall closure related complications, this study shows that barbed suture use for superficial closure after knee arthroplasty should be avoided.

Hypoxia: a critical regulator of early human tendinopathy.

OBJECTIVES: To seek evidence for the role of hypoxia in early human tendinopathy, and thereafter to explore mechanisms whereby tissue hypoxia may regulate apoptosis, inflammatory mediator expression and matrix regulation in human tenocytes. METHODS: Fifteen torn supraspinatus tendon (established pathology) and matched intact subscapularis tendon (representing 'early pathology') biopsies were collected from patients undergoing arthroscopic shoulder surgery. Control samples of the subscapularis tendon were collected from 10 patients undergoing arthroscopic stabilisation surgery. Markers of hypoxia were quantified by immunohistochemical methods. Human tendon-derived primary cells were derived from hamstring tendon tissue obtained during hamstring tendon anterior cruciate ligament reconstruction. The impact of hypoxia upon tenocyte biology ex vivo was measured using quantitative real-time PCR, multiplex cytokine assays, apoptotic proteomic profiling, immunohistochemistry and annexin V fluorescence-activated cell sorter staining. RESULTS: Increased expression of hypoxia-inducible factor 1α, Bcl-2 and clusterin was detected in subscapularis tendon samples compared with both matched torn samples and non-matched control samples (p<0.01). Hypoxic tenocytes exhibited increased production of proinflammatory cytokines (p<0.001), altered matrix regulation (p<0.01) with increased production of collagen type III operating through a mitogen-activated protein kinase-dependent pathway. Finally, hypoxia increased the expression of several mediators of apoptosis and thereby promoted tenocyte apoptosis. CONCLUSION: Hypoxia promotes the expression of proinflammatory cytokines, key apoptotic mediators and drives matrix component synthesis towards a collagen type III profile by human tenocytes. The authors propose hypoxic cell injury as a critical pathophysiological mechanism in early tendinopathy offering novel therapeutic opportunities in the management of tendon disorders.

Physical-chemical aspects of protein corona: relevance to in vitro and in vivo biological impacts of nanoparticles.

It is now clearly emerging that besides size and shape, the other primary defining element of nanoscale objects in biological media is their long-lived protein ("hard") corona. This corona may be expressed as a durable, stabilizing coating of the bare surface of nanoparticle (NP) monomers, or it may be reflected in different subpopulations of particle assemblies, each presenting a durable protein coating. Using the approach and concepts of physical chemistry, we relate studies on the composition of the protein corona at different plasma concentrations with structural data on the complexes both in situ and free from excess plasma. This enables a high degree of confidence in the meaning of the hard protein corona in a biological context. Here, we present the protein adsorption for two compositionally different NPs, namely sulfonated polystyrene and silica NPs. NP-protein complexes are characterized by differential centrifugal sedimentation, dynamic light scattering, and zeta-potential both in situ and once isolated from plasma as a function of the protein/NP surface area ratio. We then introduce a semiquantitative determination of their hard corona composition using one-dimensional sodium dodecyl sulfate-polyacrylamide gel electrophoresis and electrospray liquid chromatography mass spectrometry, which allows us to follow the total binding isotherms for the particles, identifying simultaneously the nature and amount of the most relevant proteins as a function of the plasma concentration. We find that the hard corona can evolve quite significantly as one passes from protein concentrations appropriate to in vitro cell studies to those present in in vivo studies, which has deep implications for in vitro-in vivo extrapolations and will require some consideration in the future.