Association between pain, radiographic severity, and centrally-mediated symptoms in women with knee osteoarthritis

IL24 Expression in Synovial Myofibroblasts: Implications for Female Osteoarthritis Pain through Propensity Score Matching Analysis

(1) Introduction: Despite documented clinical and pain discrepancies between male and female osteoarthritis (OA) patients, the underlying mechanisms remain unclear. Synovial myofibroblasts, implicated in synovial fibrosis and OA-related pain, offer a potential explanation for these sex differences. Additionally, interleukin-24 (IL24), known for its role in autoimmune disorders and potential myofibroblast production, adds complexity to understanding sex-specific variations in OA. We investigate its role in OA and its contribution to observed sex differences. (2) Methods: To assess gender-specific variations, we analyzed myofibroblast marker expression and IL24 levels in synovial tissue samples from propensity-matched male and female OA patients (each n = 34). Gene expression was quantified using quantitative polymerase chain reaction (qPCR). The association between IL24 expression levels and pain severity, measured by a visual analog scale (VAS), was examined to understand the link between IL24 and OA pain. Synovial fibroblast subsets, including CD45-CD31-CD39- (fibroblast) and CD45-CD31-CD39+ (myofibroblast), were magnetically isolated from female patients (n = 5), and IL24 expression was compared between these subsets. (3) Results: Females exhibited significantly higher expression of myofibroblast markers (MYH11, ET1, ENTPD2) and IL24 compared to males. IL24 expression positively correlated with pain severity in females, while no correlation was observed in males. Further exploration revealed that the myofibroblast fraction highly expressed IL24 compared to the fibroblast fraction in both male and female samples. There was no difference in the myofibroblast fraction between males and females. (4) Conclusions: Our study highlights the gender-specific role of myofibroblasts and IL24 in OA pathogenesis. Elevated IL24 levels in females, correlating with pain severity, suggest its involvement in OA pain experiences. The potential therapeutic implications of IL24, demonstrated in autoimmune disorders, open avenues for targeted interventions. Notwithstanding the limitations of the study, our findings contribute to understanding OA's multifaceted nature and advocate for future research exploring mechanistic underpinnings and clinical applications of IL24 in synovial myofibroblasts. Additionally, future research directions should focus on elucidating the precise mechanisms by which IL24 contributes to OA pathology and exploring its potential as a therapeutic target for personalized medicine approaches.

The Effect of Central Sensitization on Postoperative Neurocognitive Dysfunction in Hospitalized Elderly Patients: A Prospective Cohort Clinical Trial

OBJECTIVE

To investigate whether central sensitization (CS) in elderly patients was a predictive risk factor for postoperative neurocognitive dysfunction (PNCD).

METHODS

One hundred and thirty-three aged patients undergoing total knee arthroplasty (TKA) who received femoral nerve block and general anesthesia were recruited in this research and prospectively assigned into two groups according to the Central Sensitization Inventory (CSI) score: group C (n = 106, CSI score less than 40) and group CS (n = 27, CSI score higher than 40). Scores of Montreal Cognitive Assessment (MoCA), Mini-Mental State Examination (MMSE), Confusion Assessment Method (CAM), Numerical Rating Scale (NRS) and Quality of recovery-40 (QoR-40) questionnaires were assessed. Basic information and clinical records of all participants were also collected.

RESULTS

PNCD occurred in 24 (22.6%) of patients in group C and 16 (59.3%) in group CS (p < .05). Multivariate logistic regression analysis revealed that patients with CSI score ≥40 before surgery exhibited higher risk of PNCD after adjustment for other risk factors (p < .05). Compared to group C, the pre- and post-operative NRS scores, pain duration, the WOMAC score, and propofol consumptions for anesthesia induction were significantly increased in group CS (p < .05).

CONCLUSION

Hospitalized elderly patients with clinical symptoms of CS scores may have increased risk of PNCD following TKA.

TLR4 antagonism provides short-term but not long-term clinical benefit in a full-depth cartilage defect mouse model

PURPOSE/AIM

Cartilage injury and subsequent osteoarthritis (OA) are debilitating conditions affecting millions worldwide. As there are no cures for these ailments, novel therapies are needed to suppress disease pathogenesis. Given that joint injuries are known to produce damage-associated molecular patterns (DAMPs), our central premise is that the Toll-like receptor 4 (TLR4) pathway is a principal driver in the early response to cartilage damage and subsequent pathology. We postulate that TLR4 activation is initiated/perpetuated by DAMPs released following joint damage. Thus, antagonism of the TLR4 pathway immediately after injury may suppress the development of joint surface defects.

MATERIALS AND METHODS

Two groups were utilized: (1) 8-week-old, male C57BL6 mice treated systemically with a known TLR4 antagonist and (2) mice injected with vehicle control. A full-depth cartilage lesion on the midline of the patellofemoral groove was created in the right knee of each mouse. The left knee was used as a sham surgery control. Gait changes were evaluated over 4 weeks using a quantitative gait analysis system. At harvest, knee joints were processed for pathologic assessment, Nanostring® transcript expression, and immunohistochemistry (IHC).

RESULTS

Short-term treatment with a TLR4 antagonist at 14-days significantly improved relevant gait parameters; improved cartilage metrics and modified Mankin scores were also seen. Additionally, mRNA expression and IHC showed reduced expression of inflammatory mediators in animals treated with the TLR4 antagonist.

CONCLUSIONS

Collectively, this work demonstrates that systemic treatment with a TLR4 antagonist is protective to further cartilage damage 14-days post-injury in a murine model of induced disease.

Poor patient-reported mental health correlates with inferior patient-reported outcome measures following cervical disc replacement

PURPOSE

This study aims to assess the correlation between the patient-reported mental health and the self-reported outcome measures (PROMs) physical function, pain, and disability at different time points following disc replacement (CDR).

METHODS

A single-surgeon registry was searched for patients who had undergone CDR, excluding those with indication for infection, cancer, or trauma. One hundred fifty-one patients were included. PROMs were collected preoperatively as well as 6 weeks, 3 months, 6 months, and 1 year postoperatively. Mental health measures evaluated included 12-Item Short Form (SF-12), Mental Component Score (MCS), and Patient Health Questionnaire-9 (PHQ-9) which were individually assessed via Pearson's correlation tests in relation to Patient-Reported Outcome Measurement Information System Physical Function (PROMIS-PF), SF-12 Physical Component Score (PCS), visual analog scale (VAS) neck and arm pain, and Neck Disability Index (NDI).

RESULTS

SF-12 MCS positively correlated with PROMIS-PF (range: r = 0.369-0.614) and SF-12 PCS (range: r = 0.208-0.585) with significance found at two or more time points for each (p ≤ 0.009, all). SF-12 MCS negatively correlated with VAS neck (range: r = - 0.259 to - 0.464), VAS arm (range: r = - 0.281 to - 0.567), and NDI (range: r = - 0.474 to - 831) with significance found at three or more time points (p ≤ 0.028, all). PHQ-9 significantly negatively correlated with PROMIS-PF (range: r = - 0.457 to - 0.732) and SF-12 PCS (range: r = - 0.332 to - 0.629) at all time points (p ≤ 0.013, all). PHQ-9 positively correlated with VAS neck (range: r = 0.351-0.711), VAS arm (range: r = 0.239-0.572), and NDI (range: r = 0.602-0.837) at four or more periods (p ≤ 0.032, all).

CONCLUSION

Patients undergoing CDR who reported lower mental health scores via either SF-12 MCS or PHQ-9 were associated with increased perception of pain and disability. Disability level correlated with mental health at all time periods. Patients with optimized mental health may report higher outcome scores following CDR.

Treating Sleep Disorders After Total Hip and Total Knee Arthroplasty

Disorders of sleep are common after total hip and knee arthroplasty and may contribute to patient dissatisfaction and poorer outcomes in the early postoperative period. Multiple factors contribute to sleep disorders, including poorly controlled pain, opioid medication, perioperative stress, and anxiety. Both pharmacologic and nonpharmacologic methods have been used for perioperative sleep disorders, but there is no consensus on the optimal treatment.

Sleep Disturbances and Disorders in Patients with Knee Osteoarthritis and Total Knee Arthroplasty

➤

There is increasing evidence that patient-reported outcomes following total knee arthroplasty (TKA) are associated with psychosocial factors and pain catastrophizing. Sleep disturbance, pain, and mental health have a complex interaction, which, if unrecognized, can be associated with impaired patient-reported outcomes and dissatisfaction following TKA.

➤

The gold standard of objective sleep assessment is polysomnography, which is not feasible to use routinely for TKA patients. Wearable devices are a validated and less costly alternative.

➤

Subjective sleep measures, such as the Pittsburgh Sleep Quality Index, Epworth Sleepiness Scale, or Patient-Reported Outcomes Measurement Information System (PROMIS) computerized adaptive test sleep domains, are simple to administer and provide additional insight into sleep disturbance. Although objective and subjective measures do not correlate precisely, they can be informative together.

➤

Sleep disturbances in the elderly population are common and multifactorial in etiology, stemming from the interplay of sleep disorders, medication side effects, and pain. Commonly prescribed medications following TKA as well as postoperative pain can exacerbate underlying sleep disturbances.

➤

Obstructive sleep apnea (OSA) is prevalent in patients seeking TKA. In the setting of OSA, postoperative opioids can cause respiratory depression, resulting in consequences as severe as death. A standardized multimodal pain protocol including anti-inflammatories and gamma-aminobutyric acid (GABA) analogues may allow for decreased reliance on opioids for pain control.

➤

Surgeons should reassure patients that postoperative sleep disturbance is common and transient, collaborate with the patient's primary care doctor to address sleep disturbance, and avoid prescription of pharmaceutical sleep aids.

Quality of knee osteoarthritis care in the Netherlands: a survey on the perspective of people with osteoarthritis

BACKGROUND

Quality indicators (QIs) are used to monitor quality of care and adherence to osteoarthritis (OA) standards of care. Patient reported QIs can identify the most important gaps in quality of care and the most vulnerable patient groups. The aim of this study was to capture the perspective of people with knee OA (KOA) in the Netherlands on the quality of care received, and explore determinants related to lower achievement rates.

METHODS

We sent an online survey to all members of The Dutch Knee Panel (n = 622) of the Sint Maartenskliniek Nijmegen, the Netherlands between September and October 2019. The survey consisted of a slightly adapted version of the "OsteoArthritis Quality Indicator" (OA-QI) questionnaire (18 items; yes, no, N/A); a rating of quality of KOA care on a 10-point scale; a question on whether or not one wanted to see change in the care for KOA; and an open-ended question asking recommendations for improvement of OA care. Furthermore, sociodemographic and disease related characteristics were collected. Pass rates for separate QIs and pass rates on patient level were calculated by dividing the number of times the indicator was achieved by the number of eligible persons for that particular indicator.

RESULTS

A total of 434 participants (70%) completed the survey. The mean (SD) pass rate (those answering "Yes") for separate QIs was 49% (20%); ranging from 15% for receiving referral for weight reduction to 75% for patient education on how to manage knee OA. The mean (SD) pass rate on patient level was 52% (23%). Presence of OA in other joints, comorbidities, and having a knee replacement were associated with higher pass rates. On average, a score of 6.5 (1.6) was given for the quality of care received, and the majority of respondents (59%) wanted change in the care for KOA. Of 231 recommendations made, most often mentioned were the need for tailoring of care (14%), more education (13%), and more empathy and support from healthcare providers (12%).

CONCLUSION

This study found patients are only moderately satisfied with the OA care received, and showed substantial gaps between perceived quality of care for OA and internationally accepted standards. Future research should focus on the underlying reasons and provide strategies to bridge these gaps.

Association Between Dry Eye Syndrome and Osteoarthritis Severity: A Nationwide Cross-Sectional Study (KNHANES V)

OBJECTIVE

Recently, several researchers reported an association between osteoarthritis and dry eye syndrome (DES) and suggested that they may be related to central sensitization. We investigated the association between DES, osteoarthritis pain, and radiographic severity.

DESIGN

A nationwide, cross-sectional study.

SETTING

The Fifth Korean National Health and Nutrition Examination Survey.

SUBJECTS

8,664 participants in this survey.

METHODS

Osteoarthritis-associated radiographic changes were evaluated by trained radiologists. Multivariable logistic regression was performed to examine the relationship between osteoarthritis pain, radiographic severity, and DES. The odds ratios (ORs) of DES were analyzed in accordance with the presence of osteoarthritis-associated factors.

RESULTS

Radiographic knee osteoarthritis was significantly associated with lower ORs for DES (OR = 0.80, P = 0.046, for diagnosed/self-reported DES; OR = 0.84, P = 0.034, for symptoms of DES). Knee pain or stiffness was significantly associated with higher ORs for DES (OR = 1.28, P = 0.020, for diagnosed/self-reported DES; OR = 1.29, P = 0.003, for symptoms of DES). In patients with symptomatic osteoarthritis, DES was not significantly associated with radiographic severity of osteoarthritis. In patients with nonsymptomatic radiographic osteoarthritis, DES was inversely related with radiographic severity (Ptrend = 0.012 for diagnosed/self-reported DES; Ptrend < 0.001 for symptoms of DES).

CONCLUSIONS

Radiographic osteoarthritis showed a significant association with decreased DES. Patients with less pain and severe radiographic OA were more likely to have less DES. Our results suggest that the degree of pain caused by osteoarthritis and central sensitization may be closely associated with DES.

Macrophage regulator of G-protein signaling 12 contributes to inflammatory pain hypersensitivity

Background

Pain is a predominant symptom in rheumatoid arthritis (RA) patients that results from joint inflammation and is augmented by central sensitization. Regulator of G-protein signaling 12 (RGS12) is the largest protein in the RGS protein family and plays a key role in the development of inflammation. This study investigated the regulation of RGS12 in inflammatory pain and explored the underlying mechanisms and potential RA pain targets.

Methods

Macrophage-specific RGS12-deficient (LysM-Cre⁺;RGS12^fl/fl) mice were generated by mating RGS12^fl/fl mice with LysM-Cre⁺ transgenic mice. Collagen antibody-induced arthritis (CAIA) models were induced in LysM-Cre⁺;RGS12^fl/fl mice by the administration of a cocktail of five monoclonal antibodies and LPS. Mouse nociception was examined using the von Frey and heat plate tests. Primary macrophages and RAW264.7 cells were used to analyze the regulatory function and mechanism of RGS12 in vitro. The expression and function of RGS12 and COX2 (cyclooxygenase 2) were determined by real-time PCR, ELISA, and luciferase assays.

Results

Ablation of RGS12 in macrophages decreased pain-related phenotypes, such as paw swelling, the clinical score, and the inflammatory score, in the CAIA model. LysM-Cre⁺;RGS12^fl/fl mice displayed increased resistance to thermal and mechanical stimulation from day 3 to day 9 during CAIA, indicating the inhibition of inflammatory pain. Overexpression of COX2 and PGE2 in macrophages enhanced RGS12 expression, and PGE2 regulated RGS12 expression through the G-protein-coupled receptors EP2 and EP4. Furthermore, RGS12 or the RGS12 PTB domain strengthened the transcriptional regulation of COX2 by NF-κB, whereas inhibiting NF-κB suppressed RGS12-mediated regulation of COX2 in macrophages.

Conclusions

Our results demonstrate that the deletion of RGS12 in macrophages attenuates inflammatory pain, which is likely due to impaired regulation of the COX2/PGE2 signaling pathway.

The effect of physical therapy and rehabilitation modalities on sleep quality in patients with primary knee osteoarthritis: A single-blind, prospective, randomized-controlled study

Objectives

In this study, we aimed to evaluate the effect of physical therapy modalities on pain, sleep, mental status, and quality of life of patients with osteoarthritis (OA).

Patients and methods

Between January 2017 and June 2017, a total of 40 patients (9 males, 31 females; mean age 56.6±8.9 years; range, 40 to 70 years) who were diagnosed with knee OA according to the American College of Rheumatology (ACR) criteria and were in Kellgren- Lawrence Grade 2-3 were included in the study. The patients were divided into two groups equally. Both groups received 15 sessions of exercise therapy, whereas the intervention group also received 10 consecutive physical therapy sessions in the form of hot pack, therapeutic ultrasound (US), and transcutaneous electrical nerve stimulation (TENS) by a single physiotherapist. Isometric and isotonic exercises were planned as 10 reps for three times a day as a home-based program. Clinical assessments were performed using the visual analog scale (VAS), Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), Beck Depression Inventory (BDI), Pittsburg Sleep Quality Index (PSQI), Epworth Sleepiness Scale (ESS), and Short Form 36 (SF-36) before and after treatment.

Results

Pre-treatment VAS, ESS, PQSI, BDI, WOMAC, and SF-36 scores showed no significant difference between the groups, whereas post-treatment scores showed a significant difference in the intervention group (p<0.05). The difference between the pre- and post-treatment VAS, ESS, PQSI, BDI, WOMAC, and SF-36 scores were significantly higher in the intervention group, compared to the controls (p<0.05).

Conclusion

Our study results show positive effects of exercise and physical therapy modalities on pain, disease activity, sleep quality, depression, and quality of life in knee OA patients.

The Relationship of Three-Dimensional Joint Space Width on Weight Bearing CT With Pain and Physical Function

Limitations of plain radiographs may contribute to poor sensitivity in the detection of knee osteoarthritis and poor correlation with pain and physical function. 3D joint space width, measured from weight bearing CT images, may yield a more accurate correlation with patients' symptoms. We assessed the cross-sectional association between 3D joint space width and self-reported pain and physical function. 528 knees (57% women) were analyzed from Multicenter Osteoarthritis Study participants. An upright weight bearing CT scanner was used to acquire bilateral, weight-bearing fixed-flexion images of the knees. A 3D dataset was reconstructed from cone beam projections and joint space width was calculated across the joint surface. The percentages of the apposed medial tibiofemoral joint surface with joint space width <2.0mm and <2.5mm respectively were calculated. Pain and physical function were measured using Western Ontario and McMaster Universities Osteoarthritis Index. Participants who reported greater pain severity tended to have a greater joint area with joint space width <2.0mm (p=.07 for the highest vs. the lowest tertile). Participants who reported greater functional limitations had a greater joint area with joint space width <2.0mm (p=.02 for the highest vs. the lowest tertile). There appears to be an association between the medial tibiofemoral area with joint space width <2.0mm and pain and physical function. This article is protected by copyright. All rights reserved.

Preoperative sleep quality affects postoperative pain and function after total joint arthroplasty: a prospective cohort study

Background

The relationship between preoperative sleep quality and postoperative clinical outcomes after total joint arthroplasty (TJA) is unclear. We performed a prospective cohort study to determine whether preoperative sleep quality was correlated with postoperative outcomes after TJA.

Methods

In this prospective cohort study, 994 patients underwent TJA. Preoperative sleep measures included scores on the Pittsburgh Sleep Quality Index (PSQI), the Epworth Sleepiness Scale (ESS), and a ten-point sleep quality scale. The primary study outcome measured was the visual analog scale (VAS) pain score to 12 weeks postoperation. The consumption of analgesic rescue drugs (oxycodone and parecoxib) and postoperative length of stay (LOS) were recorded. We also measured functional parameters, including range of motion (ROM), Knee Society Score (KSS), and Harris hip score (HHS).

Results

The mean age for total knee and hip arthroplasties was 64.28 and 54.85 years, respectively. The PSQI scores were significantly correlated with nocturnal and active pain scores and ROM and functional scores from postoperative day 1 (POD1) to POD3. In addition, significant correlation was noted between the correlation between the active pain scores and ESS scores in the TKA group at postoperative 3 months. The consumption of analgesics after joint arthroplasty was significantly correlated with the PSQI scores. Moreover, significant correlations were noted between the sleep parameters and postoperative length of hospital stay (LOS).

Conclusion

Preoperative sleep parameters were correlated with clinical outcomes (i.e., pain, ROM, function, and LOS) after TJA. Clinicians should assess the sleep quality and improve it before TJA.

Psychological factors are more strongly associated with pain than radiographic severity in non-invasively treated first carpometacarpal osteoarthritis

BACKGROUND

The aim of this study was to investigate to what extent psychological factors are related to pain levels prior to non-invasive treatment in patients with osteoarthritis of the first carpometacarpal joint.

METHODS

We included patients (n = 255) at the start of non-invasive treatment for osteoarthritis of the first carpometacarpal joint who completed the Michigan Hand Outcome Questionnaire. Psychological distress, pain catastrophizing behavior and illness perception was measured. X-rays were scored on presence of scaphotrapeziotrapezoid osteoarthritis. We used hierarchical linear regression analysis to determine to what extent pain levels could be explained by patient characteristics, X-ray scores, and psychological factors.

RESULTS

Patient characteristics and X-ray scores accounted for only 6% of the variation in pre-treatment pain levels. After adding the psychological factors to our model, 47% of the variance could be explained.

CONCLUSIONS

Our results show that psychological factors are more strongly related to pain levels prior to non-invasive treatment in patients with osteoarthritis of the first carpometacarpal joint than patient characteristics and X-ray scores, which implies the important role of these factors in the reporting of symptoms. More research is needed to determine whether psychological factors will also affect treatment outcomes for patients treated non-invasively for osteoarthritis of the first carpometacarpal joint.IMPLICATIONS FOR REHABILITATIONPain is the most important complaint for patients with osteoarthritis of the first carpometacarpal joint.Psychological factors are strongly associated with pain levels prior to treatment.Pain catastrophizing behavior appears to be a promising target for complementary treatment in patients with osteoarthritis of the first carpometacarpal joint.

[What factors affect the effectiveness of long - term analgesic therapy for osteoarthritis? Data analysis of the multi - center 3-month PARACELSUS study]

There are factors that can affect the effectiveness of treatment of osteoarthritis (OA). Aim to identify factors affecting the effectiveness of long - term analgesic therapy in OA. Materials and methods. The study included 6448 patients (70.9% female and 29.1% male), middle age 57.8±10.2 years, with severe pain [≥40 mm on the visual analog scale]. All patients received the preparation of avocado - soybean unsaponifiables (ASU) 300 mg/day. For pain relief at the beginning and during the study, the drug Ketoprofen lysine salt (KLS) 320 mg/day was used. The efficiency criterion was pain reduction ≥50% and satisfaction with treatment ≥4 on a 5-point scale. The influence of a number of factors on the result of treatment was evaluated. Results. For 3 months of treatment, the pain decreased from 63.7±12.0 to 14.2±11.7 mm VAS. The result was evaluated as "good" or "excellent" 81.7% of patients. Adverse reactions were rare. In total, a good response to therapy was noted in 87.4% of patients. Gender, body mass index ≥30 kg/m2, type 2 diabetes mellitus, poor effect of non - steroidal anti - inflammatory drugs (NSAIDs) and Symptomatic Slow-Acting Drugs in Osteoarthritis (SYSADOA) in history did not affect the result. The effect was lower in persons >65 years [odds ratio (OR) 0.418; 95% confidence interval (CI) 0.342-0.509, p2 by Kellgren-Lawrence (OR 0.556; 95% CI 0.298-0.738, p.

Central sensitization is a risk factor for wound complications after primary total knee arthroplasty

PURPOSE

Postoperative wound complication is a significant risk factor for subsequent deep periprosthetic joint infection after total knee arthroplasty (TKA). Central sensitization is an abnormal enhancement of pain mechanism involving the central nervous system. Although psychological disorder is widely considered as a risk factor, the relationship between central sensitization and wound complication is currently unclear. Therefore, the purpose of this study was to investigate whether central sensitization was associated with high wound complication rate after primary TKA.

MATERIALS AND METHODS

Between January and June 2016, 161 patients undergoing unilateral TKA were prospectively divided into two groups based on central sensitization inventory score of 40 points after excluding cases with known risk factors such as physical comorbidities, health-related behaviors, and psychological disorders. Group 1 consisted of 112 patients (112 knees) whose central sensitization inventory score was < 40 points and group 2 consisted of 49 patients (49 knees) whose central sensitization inventory score was ≥ 40 points. Wound complications were defined as wound dehiscence, suture granuloma, prolonged wound oozing after postoperative day 5, significant hematoma formation, or surgical site infection recorded during the initial 90-day postoperative period. Demographic data, visual analog scale (VAS), central sensitization inventory score, and wound complications were compared between the two groups.

RESULTS

Wound complications developed in 3 (2.7%) knees in group 1 and 14 (28.6%) knees in group 2 (p < 0.001). Multivariate logistic regression analysis showed that the odds of postoperative wound complications were increased 15.7 times in patients with central sensitization inventory score ≥ 40 (95% CI 4.1-60.0, p < 0.001).

CONCLUSION

Central sensitization is a risk factor for the development of postoperative wound complication after primary TKA.

LEVEL OF EVIDENCE

II.

Relationship Between Knee Pain and Infrapatellar Fat Pad Morphology: A Within- and Between-Person Analysis From the Osteoarthritis Initiative

OBJECTIVE

Inflammation is known to be strongly associated with knee pain in osteoarthritis. The infrapatellar fat pad represents a potential source of proinflammatory cytokines. Yet the relationship between infrapatellar fat pad morphology and osteoarthritis symptoms is unclear.

METHODS

Here we investigate quantitative imaging parameters of infrapatellar fat pad morphology between painful versus contralateral pain-free legs of subjects with unilateral knee pain and patients with chronic knee pain versus those of matched pain-free control subjects. A total of 46 subjects with strictly unilateral frequent knee pain and bilateral radiographic osteoarthritis (Kellgren/Lawrence grade 2/3) were drawn from the Osteoarthritis Initiative. Further, 43 subjects with chronic knee pain over 4 years and 43 matched pain-free controls without pain over this period were studied. Infrapatellar fat pad morphology (volume, surface area, and depth) was determined by manual segmentation of sagittal magnetic resonance images.

RESULTS

No significant differences in infrapatellar fat pad morphology were observed between painful versus painless knees of persons with strictly unilateral knee pain (mean difference -0.7% (95% confidence interval [95% CI] -0.6, 0.9; P = 0.64) or between chronically painful knees versus matched painless controls (-2.1% [95% CI -2.2, 1.1]; P = 0.51).

CONCLUSION

Independent of the ambiguous role of the infrapatellar fat pad in knee osteoarthritis (a potential source of proinflammatory cytokines or a mechanical shock absorber), the size of the infrapatellar fat pad does not appear to be related to knee pain.

A Review of Chronic Pain and Cognitive, Mood, and Motor Dysfunction Following Mild Traumatic Brain Injury: Complex, Comorbid, and/or Overlapping Conditions?

Mild traumatic brain injury (mTBI) is commonly encountered in clinical practice. While the cognitive ramifications of mTBI are frequently described in the literature, the impact of mTBI on emotional, sensory, and motor function is not as commonly discussed. Chronic pain is a phenomenon more prevalent among patients with mTBI compared to those with moderate or severe traumatic brain injury. Chronic pain can become a primary disorder of the central nervous system (CNS) expressed as widespread pain, and cognitive, mood, and movement dysfunction. Shared mechanisms across chronic pain conditions can account for how pain is generated and maintained in the CNS, irrespective of the underlying structural pathology. Herein, we review the impact of mTBI on cognitive, emotional, sensory, and motor domains, and the role of pain as an important confounding variable in patient recovery and dysfunction following mTBI.

Serum interleukin 6 levels are associated with depressive state of the patients with knee osteoarthritis irrespective of disease severity

This cross-sectional study investigated the prevalence of depressive state and association between depressive state and serum interleukin (IL)-6 levels in knee osteoarthritis (OA) patients. A total of 115 painful knee OA patients were enrolled and divided into two groups according to the radiographic OA severity. Pain was evaluated using a visual analog scale (VAS). Depressive state was assessed by the self-rating depression scale (SDS). Serum IL-6 levels were also measured. Pearson's correlation coefficient was used to assess the correlation between the variants tested, and logistic regression analysis was used to identify factors associated with the depressive state. Fifty-two percent of the patients had an SDS score of ≥ 40, which is indicative of the depressive state. The pain VAS score (r = 0.22, p = 0.02) and serum IL-6 level (r = 0.31, p < 0.01) were independently associated with the SDS score of all early-stage knee OA patients (Kellgren-Lawrence [K/L] grade 2). However, only the serum IL-6 level was independently associated with the SDS scores of advanced-stage knee OA patients (K/L grades 3 and 4, r = 0.36, p < 0.01). A logistic regression analysis revealed that serum IL-6 level was the variable for the SDS score [odds ratio 1.41 (95% confidence interval 1.03-1.94, p < 0.03)]. Approximately half of the knee OA patients were found to be in the depressive state, and their serum IL-6 levels to be associated with the depressive state, irrespective of OA severity.

Central sensitization as a determinant of patients' benefit from total hip and knee replacement

Background

Discrepancies exist between osteoarthritic joint changes and pain severity before and after total hip (THR) and knee (TKR) replacement. This study investigated whether the interaction between pre‐operative widespread hyperalgesia and severity of radiographic osteoarthritis (OA) was associated with pain severity before and after joint replacement.

Methods

Data were analysed from 232 patients receiving THR and 241 receiving TKR. Pain was assessed pre‐operatively and at 12 months post‐operatively using the WOMAC Pain Scale. Widespread hyperalgesia was assessed through forearm pressure pain thresholds (PPTs). Radiographic OA was evaluated using the Kellgren and Lawrence scheme. Statistical analysis was conducted using multilevel models, and adjusted for confounding variables.

Results

Pre‐operative: In knee patients, there was weak evidence that the effect of PPTs on pain severity was greater in patients with more severe OA (Grade 3 OA: ß = 0.96 vs. Grade 4: ß = 4.03), indicating that in these patients higher PPTs (less widespread hyperalgesia) was associated with less severe pain. In hip patients, the effect of PPTs on pain did not differ with radiographic OA (Grade 3 OA: ß = 3.95 vs. Grade 4: ß = 3.67).

Post‐operative: There was weak evidence that knee patients with less severe OA who had greater widespread hyperalgesia benefitted less from surgery (Grade 3 OA: ß = 2.28; 95% CI −1.69 to 6.25). Conversely, there was weak evidence that hip patients with more severe OA who had greater widespread hyperalgesia benefitted more from surgery (Grade 4 OA: ß = −2.92; 95% CI −6.58 to 0.74).

Conclusions

Widespread sensitization may be a determinant of how much patients benefit from joint replacement, but the effect varies by joint and severity of structural joint changes.

Significance

Pre‐operative widespread hyperalgesia and radiographic osteoarthritis (OA) severity may influence how much patients benefit from joint replacement. Patients undergoing knee replacement with less severe OA and greater widespread hyperalgesia benefitted less from surgery than patients with less hyperalgesia. Patients undergoing hip replacement with more severe OA and greater widespread hyperalgesia benefitted more than patients with less hyperalgesia.

Discordant Dry Eye Disease (An American Ophthalmological Society Thesis)

PURPOSE

To improve understanding of dry eye disease and highlight a subgroup of patients who have a component of central sensitization and neuropathic pain contributing to their condition.

METHODS

Prospective, cross-sectional, IRB-approved study comparing isolated dry eye disease (n=48) to fibromyalgia (positive control; n=23) and healthy (negative control; n=26) individuals with ocular surface examination, corneal confocal microscopy, quantitative sensory testing, and self-reported ocular symptoms and systemic associations. A subset of patients also underwent skin biopsy and/or brain neuroimaging. Dry eye patients were split into concordant (ie, those with dry eyes on examination) and discordant (ie, those with dry eye symptoms but normal examination) subgroups for further analysis. We hypothesized that on the systemic measures included, concordant patients would resemble healthy controls, whereas discordant patients would show evidence of centralized mechanisms similar to fibromyalgia.

RESULTS

Schirmer test and Ocular Surface Disease Index (OSDI) scores indicated significant decreases in tear production (Schirmer: healthy, 18.5±8.2 mm; dry, 11.2±5.4 mm; fibromyalgia, 14.4±7.5; P<.001) and increases in self-reported dry eye symptoms (OSDI: healthy, 1.9±3.0; dry, 20.3±17.7; fibromyalgia, 20.3±17.1; P<.001) in the dry eye and fibromyalgia patients, compared to controls. The discordant subgroup had decreased corneal nerve density and decreased visual quality-of-life scores, similar to patients with fibromyalgia. Concordant patients were more similar to healthy controls on these measures.

CONCLUSIONS

Individuals with discordant dry eye may have a central pathophysiologic mechanism leading to their eye pain symptoms, which could be an important factor to consider in treatment of chronic idiopathic dry eye.

Prospective Evaluation of Sleep Disturbances After Total Knee Arthroplasty

Sleep disturbance after total knee arthroplasty (TKA) has not been studied 6 months after surgery. A prospective study was conducted on 34 primary, unilateral TKA patients preoperatively until 6 months postoperatively. Sleep quality was measured using the Pittsburgh Sleep Quality Index and Epworth Sleepiness Scale. Pain was measured on a visual analog scale. Sleep quality worsened from baseline during the first 6 weeks postoperatively (P = .03), but improved at 3 and 6 months (P = .003). Pain scores decreased from baseline over all time points, and there was no correlation between sleep quality and pain. The Epworth Sleepiness Scale did not change over time. This study can be used to counsel TKA patients to expect initial sleep disturbances that improve by 3 months.

Mechanical hyperalgesia and reduced quality of life occur in people with mild knee osteoarthritis pain

OBJECTIVES

This study determined whether individuals with mild knee pain due to osteoarthritis (OA) experience hyperalgesia and central sensitivity by comparing them with age-matched and sex-matched control participants and determined whether these levels are associated with pain intensity. This study also determined whether these individuals experience significantly poorer quality of life than age-matched and sex-matched controls and whether pain and function predict quality of life.

METHODS

Quantitative sensory tests (QSTs), including punctate pain intensity (PPI), pressure pain threshold (PPT), and heat pain threshold, tolerance, and temporal summation, were measured in 75 individuals with mild knee OA pain and 25 age-matched and sex-matched controls. Pain intensity, walking function, and quality of life were also assessed.

RESULTS

Significant differences were found for PPI at all sites, for PPT at the affected knee, and for quality of life. QST measures significantly correlated with pain intensity. Pain, but not function, predicted quality of life.

DISCUSSION

Individuals with mild knee pain due to OA experience mechanical (but not thermal) hyperalgesia that relates to pain intensity. They have a reduced quality of life that is predicted by pain intensity. More aggressive pain management for mild knee OA pain is indicated to improve the quality of life for individuals who are not yet candidates for joint replacement.

Risk factors associated with clinical insomnia in chronic low back pain: a retrospective analysis in a university hospital in Korea

Background

Insomnia is becoming increasingly recognized as a clinically important symptom in patients with chronic low back pain (CLBP). In this retrospective study, we have determined risk factors associated with clinical insomnia in CLBP patients in a university hospital in Korea.

Methods

Data from four-hundred and eighty one CLBP patients was analyzed in this study. The Insomnia Severity Index (ISI) was used to determine the presence of clinical insomnia (ISI score ≥ 15). Patients' demographics and pain-related factors were evaluated by logistic regression analysis to identify risk factors of clinical insomnia in CLBP.

Results

It was found that 43% of patients reported mild to severe insomnia after the development of back pain. In addition, 20% of patients met the criteria for clinically significant insomnia (ISI score ≥ 15). In a stepwise multivariate analysis, high pain intensity, the presence of comorbid musculoskeletal pain and neuropathic pain components, and high level of depression were strongly associated with clinical insomnia in CLBP. Among these factors, the presence of comorbid musculoskeletal pain other than back pain was the strongest determinant, with the highest odds ratio of 8.074 (95% CI 4.250 to 15.339) for predicting clinical insomnia.

Conclusions

Insomnia should be addressed as an integral part of pain management in CLBP patients with these risk factors, especially in patients suffering from CLBP with comorbid musculoskeletal pain.

Sleep disturbance in osteoarthritis: linkages with pain, disability, and depressive symptoms

OBJECTIVE

It is known that osteoarthritis (OA) increases the risk of sleep disturbance, and that both pain and sleep problems may trigger functional disability and depression. However, studies examining all 4 variables simultaneously are rare. The aim of this study was to examine cross-sectional and longitudinal associations of self-reported sleep disturbance with OA-related pain and disability and depressive symptoms.

METHODS

At baseline, 367 persons with physician-diagnosed knee OA reported sleep disturbances, pain, functional limitations, and depressive symptoms. At 1-year followup, all measures were repeated in 288 of the subjects. Baseline analyses examined the independent and interactive associations of sleep disturbance with pain, disability, and depression, net of demographics and general health. Longitudinal analyses used baseline sleep disturbance to predict the 1-year change in pain, disability, and depression.

RESULTS

At baseline, sleep was independently associated with pain and depression but not disability. The sleep-pain relationship was mediated by depressive symptoms; sleep interacted with pain to exacerbate depression among persons with high levels of pain. Baseline sleep disturbance predicted increased depression and disability, but not pain, at followup.

CONCLUSION

These data confirm known cross-sectional relationships between sleep disturbance and pain and depression and provide new insights regarding longitudinal associations among those variables. Depression appears to play a strong role in the sleep-pain linkage, particularly when pain is severe. The unique predictive role of sleep in the progression of disability requires further study but may be an important point of intervention to prevent OA-related functional decline among persons whose sleep is disrupted by OA-related pain.

The presence of meniscal lesions is a strong predictor of neuropathic pain in symptomatic knee osteoarthritis: a cross-sectional pilot study

Introduction

Pain in osteoarthritis (OA) has been classically attributed to joint structural damage. Disparity between the degree of radiographic structural damage and the severity of symptoms implies that factors other than the joint pathology itself contribute to the pain. Peripheral and central sensitization have been suggested as two of the underlying mechanisms that contribute to pain in OA. The aim of this study was to explore in symptomatic knee OA patients, the structural changes assessed by magnetic resonance imaging (MRI) that could be used as markers of neuropathic pain (NP).

Methods

This cross-sectional observational pilot study included 50 knee OA patients with moderate to severe pain (VAS ≥40) in the target knee. The presence of NP was determined based on the PainDETECT questionnaire. Among the 50 patients included, 25 had PainDETECT score ≤12 (unlikely NP), 9 had PainDETECT score between 13 and 18 (uncertain NP) and 16 had PainDETECT score ≥19 (likely NP). WOMAC, PainDETECT, and VAS pain scores as well as knee MRI were assessed.

Results

Data showed no significant difference in demographic characteristics between the three groups. However, a positive and statistically significant association was found between the WOMAC pain (P <0.001), function (P <0.001), stiffness (P = 0.007) and total (P <0.001) scores as well as higher VAS pain score (P = 0.023), and PainDETECT scores. Although no difference was found in the cartilage volume between groups, the presence of meniscal extrusion in both medial (P = 0.006) and lateral (P = 0.023) compartments, and presence of meniscal tears in the lateral compartment (P = 0.011), were significantly associated with increasing PainDETECT score. Moreover, the presence of bone marrow lesions in the lateral plateau and the extent of the synovial membrane thickness in the lateral recess were associated with increasing PainDETECT scores (P = 0.032, P = 0.027, respectively).

Conclusions

In this study, meniscal lesions, particularly extrusion, were found to be among the strongest risk factors for NP in knee OA patients.

Trial registration

ClinicalTrials.gov NCT01733277. Registered 16 November 2012.

Subjective and Objective Sleep Quality in Individuals with Osteoarthritis in Taiwan

OBJECTIVES

The negative effects of osteoarthritis (OA), such as pain and depression, interfere with an individual's sleep quality. The main objective of the present study was to investigate the prevalence of poor quality of sleep in individuals with OA in Taiwan and identify potential predictors. A secondary objective was to examine agreement between objective and subjective measures of sleep quality.

METHODS

In a cross-sectional survey, OA outpatients in Taiwan completed a self-administered questionnaire, incorporating validated measurements for assessing quality of sleep (the Pittsburgh Sleep Quality Index (PSQI)), pain and physical functioning, anxiety and depression, and health-related quality of life. In a nested feasibility study, a sub-sample of participants wore an Actigraph wrist monitor to measure sleep objectively over a three-day period.

RESULTS

Of 192 individuals with OA who completed the survey, 30 completed the Actigraph study. The mean PSQI global score was 9.0 (standard deviation 4.5); most participants (135, 70.3%) had poor quality of sleep (global PSQI >5). Key predictors of poor quality of sleep included role limitation due to poor physical functioning, poor social functioning, higher anxiety levels and higher pain levels. There were moderate correlations between subjective and objective measures of sleep quality, although participants underestimated their true sleeping time by two hours.

CONCLUSIONS

Health professionals need to discuss sleep issues with individuals with OA and include strategies for coping with these difficulties. For reduced night-time pain which may interfere with sleep, additional and appropriate advice about medication is required. Copyright © 2014 John Wiley & Sons, Ltd.

Future directions in painful knee osteoarthritis: harnessing complexity in a heterogeneous population

This perspective article proposes a conceptual model for the pain experience for individuals diagnosed with knee osteoarthritis (OA). Pain in knee OA is likely a heterogeneous, multifactorial phenomenon that involves not only the OA disease process but also elements specific to patient psychology and pain neurophysiology. The relevant contributions to the pain experience for any individual patient remain difficult, if not impossible, to definitively determine, and the rationale for many clinical treatment decisions arises primarily from a mechanistic understanding of OA pathophysiology. The Osteoarthritis Research Society International (OARSI) recently identified "phenotyping" of OA pain as a research priority to "better target pain therapies to individual patients." This perspective article proposes that contributions from 3 domains--knee pathology, psychological distress, and pain neurophysiology--should be considered equally important in future efforts to understand pain phenotypes in knee OA. Ultimately, characterization of pain phenotypes may aid in the understanding of the pain experience and the development of interventions specific to pain for individual patients.

Pain treatment for patients with osteoarthritis and central sensitization

Osteoarthritis is one of the most frequent, disabling, and costly pathologies of modern society. Among the main aims of osteoarthritis management are pain control and functional ability improvement. The exact cause of osteoarthritis pain remains unclear. In addition to the pathological changes in articular structures, changes in central pain processing or central sensitization appear to be involved in osteoarthritis pain. The latter calls for a broader approach to the management of patients with osteoarthritis. Yet, the scientific literature offers scant information addressing the treatment of central sensitization, specifically in patients with osteoarthritis. Interventions such as cognitive-behavioral therapy and neuroscience education potentially target cognitive-emotional sensitization (and descending facilitation), and centrally acting drugs and exercise therapy can improve endogenous analgesia (descending inhibition) in patients with osteoarthritis. Future studies should assess these new treatment avenues.

Effect and treatment of chronic pain in inflammatory arthritis

Pain is the most common reason patients with inflammatory arthritis see a rheumatologist. Patients consistently rate pain as one of their highest priorities, and pain is the single most important determinant of patient global assessment of disease activity. Although pain is commonly interpreted as a marker of inflammation, the correlation between pain intensity and measures of peripheral inflammation is imperfect. The prevalence of chronic, non-inflammatory pain syndromes such as fibromyalgia is higher among patients with inflammatory arthritis than in the general population. Inflammatory arthritis patients with fibromyalgia have higher measures of disease activity and lower quality of life than inflammatory patients who do not have fibromyalgia. This review article focuses on current literature involving the effects of pain on disease assessment and quality of life for patients with inflammatory arthritis. It also reviews non-pharmacologic and pharmacologic options for treatment of pain for patients with inflammatory arthritis, focusing on the implications of comorbidities and concurrent disease-modifying antirheumatic drug therapy. Although several studies have examined the effects of reducing inflammation for patients with inflammatory arthritis, very few clinical trials have examined the safety and efficacy of treatment directed specifically towards pain pathways. Most studies have been small, have focused on rheumatoid arthritis or mixed populations (e.g., rheumatoid arthritis plus osteoarthritis), and have been at high risk of bias. Larger, longitudinal studies are needed to examine the mechanisms of pain in inflammatory arthritis and to determine the safety and efficacy of analgesic medications in this specific patient population.