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.

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.

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.

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.

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.