Chronic, Active Inflammation in Patients With Failed Total Knee Replacements Undergoing Revision Surgery

Markers of Tissue Deterioration and Pain on Earth and in Space

Purpose

Pain is an understudied physiological effect of spaceflight. Changes in inflammatory and tissue degradation markers are often associated with painful conditions. Our aim was to evaluate the changes in markers associated with tissue deterioration after a short-term spaceflight.

Patients and Methods

Plasma levels of markers for systemic inflammation and tissue degeneration markers were assessed in two astronauts before and within 24 h after the 17-day Axiom Space AX-1 mission.

Results

After the spaceflight, C-reactive protein (CRP) was reduced in both astronauts, while INFγ, GM-CSF, TNFα, BDNF, and all measured interleukins were consistently increased. Chemokines demonstrated variable changes, with consistent positive changes in CCL3, 4, 8, 22 and CXCL8, 9, 10, and consistent negative change in CCL8. Markers associated with tissue degradation and bone turnover demonstrated consistent increases in MMP1, MMP13, NTX and OPG, and consistent decreases in MMP3 and MMP9.

Conclusion

Spaceflight induced changes in the markers of systemic inflammation, tissue deterioration, and bone resorption in two astronauts after a short, 17-day, which were often consistent with those observed in painful conditions on Earth. However, some differences, such as a consistent decrease in CRP, were noted. All records for the effect of space travel on human health are critical for improving our understanding of the effect of this unique environment on humans.

A potential link between inflammatory profiles, clinical pain, pain catastrophizing and long-term outcomes after total knee arthroplasty surgery

BACKGROUND

Chronic postoperative pain after total knee replacement (TKR) is a major clinical problem. It is still unclear if specific inflammatory mediators are associated with long-term postoperative pain complications. The current exploratory study aimed to (1) evaluate a multiplex of inflammatory mediators 5 years after TKR surgery in patients with different degrees of postoperative pain intensities and (2) study any association of the markers with clinical pain intensity, cognitive and functional outcomes.

METHODS

Plasma samples were collected 5 years after TKR surgery from 76 knee patients (43 females; 33 males) and analysed for 44 inflammatory markers. Pain (using visual analogue scale, VAS), the pain catastrophizing scale (PCS) and the Oxford knee score (OKS) were evaluated. Patients were categorized as high or low groups based on VAS, PCS and OKS scores. Associations between inflammatory markers, VAS, PCS and OKS were analysed and the marker expressions were compared between groups.

RESULTS

Pearson's correlations found 12 biomarkers associated with VAS (p < 0.05), 4 biomarkers with PCS and 3 biomarkers with OKS (p < 0.05). Four markers were altered in patients suffering from high compared to low chronic postoperative pain, three markers were altered in high compared to low catastrophizers and three markers were altered in patients with poor functional scores (p < 0.05).

CONCLUSIONS

The present exploratory study suggests that low-grade inflammation might be present in a subset of patients with high pain, high catastrophizing and low function 5 years after TKR. These exploratory results provide insights into some of the long-term postoperative complications after TKR surgery.

SIGNIFICANCE STATEMENT

This exploratory study evaluated a subset of inflammatory markers and the association to clinical pain intensity, knee function and pain catastrophizing in patients 5 years after total knee replacement surgery. Our results provide insights into the understanding of the underlying mechanisms that may drive the long experience of pain after TKR surgery.

No Difference in Range of Motion, Components, or Complications Following Conversion of Robotic-Assisted Total Knee Arthroplasty Compared to Manual TKA After Undergoing Manual or Robotic-Assisted Unicompartmental Knee Arthroplasty

Background

Conversion surgery from unicondylar knee arthroplasty (UKA) to total knee arthroplasty (TKA) remains a challenge due to scarring, implant/cement removal, and loss of bony landmarks. Robotic-assisted (RA) TKA may assist in challenges seen in manual conversion TKA. The aim of this study is to identify if there are differences in components and functional outcomes dependent on manual/RA primary UKA and conversion TKA.

Methods

A retrospective chart review was performed on patients undergoing conversion from UKA to TKA over a 10-year period at a single institution. Data extracted included surgical technique, reason for UKA failure, range of motion at 1 year, need for augments, and utilization of revision components.

Results

Forty-nine patients (50 knees) with a UKA converted to a TKA were divided into 4 groups based on primary and conversion surgery: manual-to-manual (n = 11), manual-to-robot (n = 11), robot-to-manual (n = 11), and robot-to-robot (n = 17). There was no difference in need for augments (P = .376), size of poly (P = .23), postoperative flexion (P = .52), or extension (P = .76) at 1 year between the 4 groups. However, patients with primary manual UKA did require significantly more augments during revision (P = .032).

Conclusions

Our study did not show any statistically significant differences of primary RA or manual UKA to RA or manual TKA in terms of range of motion at 1 year, complications, or differences in components. RA conversion from UKA to TKA is a new but equivalent technique to manual conversion. Primary surgery may impact the requirement for augments during conversion surgery.

Effectiveness of Geniculate Artery Embolization for Chronic Pain after Total Knee Replacement-A Pilot Study

PURPOSE

To evaluate the efficacy and safety of embolization of hyperemic synovial tissue for the treatment of persistent pain after total knee arthroplasty (TKA).

MATERIALS AND METHODS

Twelve patients with persistent pain after TKA were enrolled in this prospective, single-center pilot study. Genicular artery embolization (GAE) was performed using 75-μm spherical particles. The patients were assessed using a 100-point Visual Analog Scale (VAS) and Knee Injury and Osteoarthritis Outcome Score (KOOS) at baseline and 3 and 6 months thereafter. Adverse events were recorded at all time points.

RESULTS

A mean of 1.8 ± 0.8 abnormal hyperemic genicular arteries were identified and embolized, with a median volume of diluted embolic material of 4.3 mL in all 12 (100%) patients. The mean VAS score on walking improved from 73 ± 16 at baseline to 38 ± 35 at the 6-month follow-up (P < .05). The mean KOOS pain score improved from 43.6 ± 15.5 at baseline to 64.6 ± 27.1 at the 6-month follow-up (P < .05). At the 6-month follow-up, 55% and 73% of the patients attained a minimal clinically important change in pain and quality of life, respectively. Self-limited skin discoloration occurred in 5 (42%) patients. The VAS score increased by more than 20 immediately after embolization in 4 (30%) patients, who required analgesic treatment for 1 week.

CONCLUSION

GAE is a safe method of treating persistent pain after TKA that demonstrates potential efficacy at 12 months.

Better post-operative outcomes at 1-year follow-up are associated with lower levels of pre-operative synovitis and higher levels of IL-6 and VEGFA in unicompartmental knee arthroplasty patients

PURPOSE

Osteoarthritis (OA) is associated with inflammation, and residual inflammation may influence outcomes following knee arthroplasty. This may be more relevant for patients undergoing unicompartmental knee arthroplasty (UKA) due to larger remaining areas of native tissue. This study aimed to: (1) characterise inflammatory profiles for medial UKA patients and (2) investigate whether inflammation markers are associated with post-operative outcomes.

METHODS

This prospective, observational study has national ethics approval. Bloods, synovial fluid, tibial plateaus and synovium were collected from medial UKA patients in between 1 January 2021 and 31 December 2021. Cytokine and chemokine concentrations in serum and synovial fluid (SF) were measured with multiplexed assays. Disease severity of cartilage and synovium was assessed using validated histological scores. Post-operative outcomes were measured with Oxford Knee Score (OKS), Forgotten Joint Score (FJS-12) and pain scores.

RESULTS

The study included 35 patients. SF VEGFA was negatively correlated with pre-operative pain at rest (r - 0.5, p = 0.007), and FJS-12 at six-week (r 0.44, p = 0.02), six-month (r 0.61, p < 0.01) and one-year follow-up (r 0.63, p = 0.03). Serum and SF IL-6 were positively correlated with OKS at early follow-up (serum 6 weeks, r 0.39, p = 0.03; 6 months, r 0.48, p < 0.01; SF 6 weeks, r 0.35, p = 0.04). At six weeks, increased synovitis was negatively correlated with improvements in pain at rest (r - 0.41, p = 0.03) and with mobilisation (r - 0.37, p = 0.047).

CONCLUSION

Lower levels of synovitis and higher levels of IL-6 and VEGFA were associated with better post-operative outcomes after UKA, which could be helpful for identifying UKA patients in clinical practice.

LEVEL OF EVIDENCE

Level IV case series.

Targeting Members of the Chemokine Family as a Novel Approach to Treating Neuropathic Pain

Neuropathic pain is a debilitating condition that affects millions of people worldwide. Numerous studies indicate that this type of pain is a chronic condition with a complex mechanism that tends to worsen over time, leading to a significant deterioration in patients' quality of life and issues like depression, disability, and disturbed sleep. Presently used analgesics are not effective enough in neuropathy treatment and may cause many side effects due to the high doses needed. In recent years, many researchers have pointed to the important role of chemokines not only in the development and maintenance of neuropathy but also in the effectiveness of analgesic drugs. Currently, approximately 50 chemokines are known to act through 20 different seven-transmembrane G-protein-coupled receptors located on the surface of neuronal, glial, and immune cells. Data from recent years clearly indicate that more chemokines than initially thought (CCL1/2/3/5/7/8/9/11, CXCL3/9/10/12/13/14/17; XCL1, CX3CL1) have pronociceptive properties; therefore, blocking their action by using neutralizing antibodies, inhibiting their synthesis, or blocking their receptors brings neuropathic pain relief. Several of them (CCL1/2/3/7/9/XCL1) have been shown to be able to reduce opioid drug effectiveness in neuropathy, and neutralizing antibodies against them can restore morphine and/or buprenorphine analgesia. The latest research provides irrefutable evidence that chemokine receptors are promising targets for pharmacotherapy; chemokine receptor antagonists can relieve pain of different etiologies, and most of them are able to enhance opioid analgesia, for example, the blockade of CCR1 (J113863), CCR2 (RS504393), CCR3 (SB328437), CCR4 (C021), CCR5 (maraviroc/AZD5672/TAK-220), CXCR2 (NVPCXCR220/SB225002), CXCR3 (NBI-74330/AMG487), CXCR4 (AMD3100/AMD3465), and XCR1 (vMIP-II). Recent research has shown that multitarget antagonists of chemokine receptors, such as CCR2/5 (cenicriviroc), CXCR1/2 (reparixin), and CCR2/CCR5/CCR8 (RAP-103), are also very effective painkillers. A multidirectional strategy based on the modulation of neuronal-glial-immune interactions by changing the activity of the chemokine family can significantly improve the quality of life of patients suffering from neuropathic pain. However, members of the chemokine family are still underestimated pharmacological targets for pain treatment. In this article, we review the literature and provide new insights into the role of chemokines and their receptors in neuropathic pain.

Targeting the chemokine ligand 2-chemokine receptor 2 axis provides the possibility of immunotherapy in chronic pain

Chronic pain affects patients' physical and psychological health and quality of life, entailing a tremendous public health challenge. Currently, drugs for chronic pain are usually associated with a large number of side effects and poor efficacy. Chemokines in the neuroimmune interface combine with their receptors to regulate inflammation or mediate neuroinflammation in the peripheral and central nervous system. Targeting chemokines and their receptor-mediated neuroinflammation is an effective means to treat chronic pain. In recent years, growing evidence has shown that the expression of chemokine ligand 2 (CCL2) and its main chemokine receptor 2 (CCR2) is involved in its occurrence, development and maintenance of chronic pain. This paper summarises the relationship between the chemokine system, CCL2/CCR2 axis, and chronic pain, and the CCL2/CCR2 axis changes under different chronic pain conditions. Targeting chemokine CCL2 and its chemokine receptor CCR2 through siRNA, blocking antibodies, or small molecule antagonists may provide new therapeutic possibilities for managing chronic pain.

Diagnostic Utility and Thresholds for Commonly Obtained Serum and Synovial Markers Prior to Reimplantation in Periprosthetic Joint Infection

BACKGROUND

Accurate diagnosis of persistent periprosthetic joint infection (PJI) during 2-stage exchange remains a challenge. This study evaluated the diagnostic performance and thresholds of several commonly obtained serum and synovial markers to better guide reimplantation timing.

METHODS

This was a retrospective review of 249 patients who underwent 2-stage exchange with antibiotic spacers for PJI. Serum and synovial markers analyzed included white blood cell (WBC) count, polymorphonuclear percentage (PMN%), neutrophil-to-lymphocyte ratio (NLR), and absolute neutrophil count (ANC). Serum markers analyzed were erythrocyte sedimentation rate (ESR), C-reactive protein (CRP), as well as percentage change in ESR and CRP from initial diagnosis to reimplantation. Area under the curve (AUC) analyses were performed to determine diagnostic accuracy of detecting PJI.

RESULTS

In TKAs, synovial ANC and WBC had the highest AUCs (0.76), with thresholds of 2,952 and 3,800 cells/μL, respectively. The next best marker was serum CRP (0.73) with a threshold of 5.2 mg/dL. In THAs, serum CRP had the highest AUC (0.84) with a threshold of 4.3 mg/dL, followed by synovial PMN% (0.80) with a threshold of 77%. Percentage change in serum ESR or CRP provided low diagnostic value overall.

CONCLUSION

Regarding serum markers, CRP consistently performed well in detecting persistent PJI in patients with antibiotic spacers. Absolute values of serum CRP and ESR had better diagnostic value than trends for guiding reimplantation timing. Diagnostic performance differed with joint type; however, synovial markers outperformed serum counterparts. No marker alone can be utilized to diagnose residual PJI in these patients, and further work is needed in this domain.

Pulsed electromagnetic fields improve pain management and clinical outcomes after medial unicompartmental knee arthroplasty: A prospective randomised controlled trial

BACKGROUND

To assess pain relief and clinical outcomes in patients undergoing unicompartmental knee arthroplasty (UKA) stimulated with pulsed electromagnetic fields (PEMFs) compared to a control group.

METHODS

A prospective randomised controlled trial (RCT) was performed in which 72 patients undergoing medial UKA were randomised into a control group or an experimental PEMFs group. The patients allocated to the experimental group were instructed to use PEMFs for 4 h per day for 60 days. They were evaluated before a surgery and then during the time points corresponding to 1 month, 2 months, 6 months, 12 months, and 36 months after the surgery. No placebo group was included in the RCT. Clinical assessment included the Visual Analogue Scale (VAS) for pain, Oxford Knee Score (OKS), the Short Form 36 (SF-36) health survey questionnaire, and joint swelling. During each follow-up visit, the consumption of Non-Steroidal Anti-Inflammatory Drugs (NSAIDs) was recorded.

RESULTS

The VAS decreased on follow-up visits in both the groups; a statistically significant difference between the groups was observed during the 6 (p = 0.0297), 12 (p = 0.0003), and 36 months (p = 0.0333) follow-ups in favour of the PEMFs group. One month after UKA, the percentages of patients using NSAIDs in the PEMFs and control group were 71% and 92%, respectively (p = 0.0320). At the 2 months point, 15% of the patients in the PEMFs group used NSAIDs compared to 39% in the control group (p = 0.0317). The objective knee girth evaluation showed a statistically significant difference at 6 (p = 0.0204), 12 (p = 0.0005), and 36 (p = 0.0005) months with improved values observed in the PEMFs group. The subjective assessment of the swelling demonstrated a statistically significant difference at 2 (p = 0.0073), 6 (p = 0.0006), 12 (p = 0.0001), and 36 (p = 0.0011) months with better values noted in the PEMFs group. Last, the OKS result was significant higher in the experimental group during all the follow-ups (1mth: p = 0.0295; 2mths: p = 0.0012; 6mths: p = 0.0001; 12mths: p < 0.0001; 36mths: p = 0.0061).

CONCLUSIONS

The use of PEMFs leads to significant pain relief, better clinical improvement, and lower NSAIDs consumption after medial UKA when compared to the control group.

LEVEL OF EVIDENCE

II.

Investigating Molecular Signatures Underlying Trapeziometacarpal Osteoarthritis Through the Evaluation of Systemic Cytokine Expression

Purpose

Non-operative management of trapeziometacarpal osteoarthritis (TMOA) demonstrates only short-term symptomatic alleviation, and no approved disease modifying drugs exist to treat this condition. A key issue in these patients is that radiographic disease severity can be discordant with patient reported pain, illustrating the need to identify molecular mediators of disease. This study characterizes the biochemical profile of TMOA patients to elucidate molecular mechanisms driving TMOA progression.

Methods

Plasma from patients with symptomatic TMOA undergoing surgical (n=39) or non-surgical management (n=44) with 1-year post-surgical follow-up were compared using a targeted panel of 27 cytokines. Radiographic (Eaton-Littler), anthropometric, longitudinal pain (VAS, TASD, quick DASH) and functional (key pinch, grip strength) data were used to evaluate relationships between structure, pain, and systemic cytokine expression. Principal Component Analysis was used to identify clusters of patients.

Results

Patients undergoing surgery had greater BMI as well as higher baseline quick DASH, TASD scores. Systemically, these patients could only be distinguished by differing levels of Interleukin-7 (IL-7), with an adjusted odds ratio of 0.22 for surgery for those with increased levels of this cytokine. Interestingly, PCA analysis of all patients (regardless of surgical status) identified a subset of patients with an “inflammatory” phenotype, as defined by a unique molecular signature consisting of thirteen cytokines.

Conclusion

Overall, this study demonstrated that circulating cytokines are capable of distinguishing TMOA disease severity, and identified IL-7 as a target capable of differentiating disease severity with higher levels associated with a decreased likelihood of TMOA needing surgical intervention. It also identified a cluster of patients who segregate based on a molecular signature of select cytokines.

Inflammatory responses to metal oxide ceramic nanopowders

Ceramic orthopaedic implants are increasingly popular due to the need for robust total joint replacement implants that have a high success rate long-term and do not induce biological responses in patients. This study was designed to investigate the biological effects of ceramic nanopowders containing aluminium oxide or zirconium oxide to activate the human macrophage THP-1 cell line. In vitro investigation of pro-inflammatory gene expression and chemokine secretion was performed studied using RT-qPCR and ELISA, respectively. TLR4 inhibition, using a small-molecule inhibitor, was used to determine whether ceramic-mediated inflammation occurs in a similar manner to that of metals such as cobalt. THP-1 macrophages were primed with ceramics or LPS and then treated with ATP or ceramics, respectively, to determine whether these nanopowders are involved in the priming or activation of the NLRP3 inflammasome through IL-1β secretion. Cells treated with ceramics significantly increased pro-inflammatory gene expression and protein secretion which was attenuated through TLR4 blockade. Addition of ATP to cells following ceramic treatment significantly increased IL-1β secretion. Therefore, we identify the ability of ceramic metal oxides to cause a pro-inflammatory phenotype in THP-1 macrophages and propose the mechanism by which this occurs is primarily via the TLR4 pathway which contributes to inflammasome signalling.

Causes of stiffness after total knee arthroplasty: a systematic review

BACKGROUND

Knee stiffness after total knee arthroplasty (TKA) often leads to pain and discomfort, failing to meet patients' expectations on the surgical procedure. Despite the growing debate on the topic, a comprehensive literature analysis of stiffness causes has never been conducted. Thus, the purpose of the present study was to systematically review the literature regarding the main causes of stiffness after TKA.

METHODS

Pubmed Central, Scopus, and EMBASE databases were systematically reviewed according to the Preferred Reporting Items for Systematic Reviews and Meta-analysis (PRISMA) guidelines for studies on stiffness and pain or discomfort after TKA through November 2020. Overall, 25 articles matched the selection criteria and were included in the study. Clinical relevance and strength of evidence of the included studies were graded using the risk of bias and the methodological index for non-randomized studies quality assessment tools.

RESULTS

The main causes of pain and discomfort due to stiffness were surgery-related issues, i.e., component malpositioning and over-voluming, implant loosening, psychological distress, and obesity, which could be considered "modifiable" factors, and expression of profibrotic markers, high material hypersensitivity-related cytokines level, male gender, previous contralateral TKA, and high pre-operative pain, which could be considered "non-modifiable" factors.

CONCLUSION

The use of alternative technologies such as surgical robots, anatomy-based devices, and more inert and less stiff component materials could help in reducing stiffness caused by both modifiable and even some non-modifiable factors. Furthermore, early diagnostic detection of stiffness onset could consistently support surgeons in patient-specific decision-making.

lncRNA SNHG16 promotes the occurrence of osteoarthritis by sponging miR‑373‑3p

Osteoarthritis (OA) is a common age‑related joint disorder, for which no effective disease‑modifying drugs are currently available. Long non‑coding RNAs (lncRNAs) are involved in the occurrence of OA. lncRNA small nucleolar RNA host gene 16 (SNHG16) has been reported to regulate inflammation; however, the exact biological function of SNHG16 in OA and its underlying mechanism of action remain unclear. In this study, gene and protein expression levels were detected using reverse transcription‑quantitative PCR and western blotting, respectively. Cell apoptosis was analyzed using flow cytometry and ELISA was performed to detect TNF‑α levels. The interactions between lncRNA SNHG16 and microRNA (miR)‑373‑3p were examined using the dual‑luciferase reporter assay. lncRNA SNHG16 was upregulated in OA tissue compared with normal joint tissue. The expression levels of collagen II were significantly reduced in OA tissue compared with normal tissue. Similarly, aggrecan expression levels were significantly reduced in IL‑1β‑treated CHON‑001 cells compared with the controls. In addition, the protein expression levels of MMP13 were significantly increased in OA tissues and IL‑1β‑treated CHON‑001 cells compared with the controls. SNHG16 knockdown significantly increased the expression levels of aggrecan, and decreased the expression levels of MMP13, cleaved caspase‑3 and p21 in IL‑1β‑treated CHON‑001 cells. In addition, IL‑1β induced CHON‑001 cell apoptosis, while SNHG16 knockdown decreased IL‑1β‑induced apoptosis. Furthermore, the luciferase activity assay suggested that SNHG16 negatively regulated miR‑373‑3p in OA. Finally, the results suggested that the proinflammatory effect of IL‑1β on CHON‑001 cells was significantly reduced by SNHG16 knockdown. In conclusion, lncRNA SNHG16 knockdown significantly limited the progression of OA by sponging miR‑373‑3p in vitro, which suggested that SNHG16 may serve as a potential therapeutic target for OA.

Quantification of intra-articular fibrosis in patients with stiff knee arthroplasties using metal-reduction MRI

AIMS

Stiffness is a common complication after total knee arthroplasty (TKA). Pathogenesis is not understood, treatment options are limited, and diagnosis is challenging. The aim of this study was to investigate if MRI can be used to visualize intra-articular scarring in patients with stiff, painful knee arthroplasties.

METHODS

Well-functioning primary TKAs (n = 11), failed non-fibrotic TKAs (n = 5), and patients with a clinical diagnosis of fibrosis1 (n = 8) underwent an MRI scan with advanced metal suppression (Slice Encoding for Metal Artefact Correction, SEMAC) with gadolinium contrast. Fibrotic tissue (low intensity on T1 and T2, low-moderate post-contrast enhancement) was quantified (presence and tissue thickness) in six compartments: supra/infrapatella, medial/lateral gutters, and posterior medial/lateral.

RESULTS

Fibrotic tissue was identified in all patients studied. However, tissue was significantly thicker in fibrotic patients (4.4 mm ± 0.2 mm) versus non-fibrotic (2.5 mm ± 0.4 mm) and normal TKAs (1.9 mm ± 0.2 mm, p = < 0.05). Significant (> 4 mm thick) tissue was seen in 26/48 (54%) of compartments examined in the fibrotic group, compared with 17/30 (57%) non-fibrotic, and 10/66 (15%) normal TKAs. Although revision surgery did improve range of movement (ROM) in all fibrotic patients, clinically significant restriction remained post-surgery.

CONCLUSION

Stiff TKAs contain intra-articular fibrotic tissue that is identifiable by MRI. Studies should evaluate whether MRI is useful for surgical planning of debridement, and as a non-invasive measurement tool following interventions for stiffness caused by fibrosis. Revision for stiffness can improve ROM, but outcomes are sub-optimal and new treatments are required. Cite this article: Bone Joint J 2020;102-B(10):1331-1340.

Everolimus reduces postoperative arthrofibrosis in rabbits by inducing autophagy-mediated fibroblast apoptosis by PI3K/Akt/mTOR signaling pathway

OBJECTIVE

To investigate the effects of everolimus (EVE) on postoperative fibrosis in the knee joint and the potentially relevant signaling pathways.

METHODS

CCK-8 and flow cytometry assays were used to detect the effect of EVE on human fibroblast viability and apoptosis induction. IF and TEM were used to assess fibroblast autophagy. 3-methyladenine (3-MA) was applied to inhibit autophagy to clarify the relationship between autophagy and apoptosis. WB was used to measure the expression of proteins related to apoptosis, autophagy and the mTOR signaling pathway. A rabbit model of knee joint fibrosis was established and topically treated with various concentrations of EVE. IF-P was applied to identify that the main components cells of the fibrotic tissue and histomorphological staining was used to detect the degree of fibrosis and the content of collagen.

RESULTS

Histomorphological staining demonstrated that EVE could reduce the degree of postoperative fibrosis and collagen deposition in the knee joint. The results of IF, TEM, flow cytometry assays and WB detection showed that EVE could activate autophagy and induce fibroblasts apoptosis. Meanwhile, the expression levels of p-PI3K, p-Akt, p-mTOR were downregulated with EVE treatment. After the inhibition of autophagy by 3-MA treatment, the increased fibroblasts apoptosis by EVE treatment was partially decreased.

CONCLUSION

Everolimus can reduce surgery-induced knee fibrosis by inducing autophagy-mediated fibroblast apoptosis, which may be involved with the regulation of the PI3K/Akt/mTOR signaling pathway.

Endovascular Occlusion of Neovascularization as a Treatment for Persistent Pain After Total Knee Arthroplasty

Approximately 20% of patients have persistent unexplained pain after total knee arthroplasty (TKA). Currently available treatments are unsatisfactory. The present report describes four patients in whom transcatheter arterial embolization had a remarkable effect on pain after TKA. Abnormal neovessels were identified in all patients. For 48 h, one patient experienced remarkable postprocedural pain at the inner side of the knee that was subsided by level 1 analgesics and another patient development of a spontaneous skin ulceration resolving within 8 days. The mean Knee injury and Osteoarthritis Outcome Score pain subtotal had increased from 39 to 82 one month after treatment. Endovascular occlusion of neovascularization, decreasing chronic inflammation and the growth of unmyelinated sensory nerves may be treatment options for persistent unexplained pain following TKA.Level of Evidence IV, Case report.

Diagnosis and management of implant debris-associated inflammation

Introduction: Total joint replacement is one of the most common, safe, and efficacious operations in all of surgery. However, one major long-standing and unresolved issue is the adverse biological reaction to byproducts of wear from the bearing surfaces and modular articulations. These inflammatory reactions are mediated by the innate and adaptive immune systems.Areas covered: We review the etiology and pathophysiology of implant debris-associated inflammation, the clinical presentation and detailed work-up of these cases, and the principles and outcomes of non-operative and operative management. Furthermore, we suggest future strategies for prevention and novel treatments of implant-related adverse biological reactions.Expert opinion: The generation of byproducts from joint replacements is inevitable, due to repetitive loading of the implants. A clear understanding of the relevant biological principles, clinical presentations, investigative measures and treatments for implant-associated inflammatory reactions and periprosthetic osteolysis will help identify and treat patients with this issue earlier and more effectively. Although progressive implant-associated osteolysis is currently a condition that is treated surgically, with further research, it is hoped that non-operative biological interventions could prolong the lifetime of joint replacements that are otherwise functional and still salvageable.