Pressure pain thresholds in individuals with knee pain: a cross-sectional study

Association between obesity measurement indexes and symptomatic knee osteoarthritis among the Chinese population: analysis from a nationwide longitudinal study

BACKGROUND

The current literature lacks robust clinical data and evidence delineating the relationship between obesity measurement indexes and knee osteoarthritis (KOA). Consequently, this investigation seeks to elucidate the potential link between obesity measurement indexes and KOA among Chinese adults in a nationally representative study.

METHODS

Firstly, this research performed an observational study in the China Health and Retirement Longitudinal Study (CHARLS). The variables were extracted from interviews and compared between KOA and non-KOA participants. The relationship between obesity measurement indexes and KOA was analyzed by multivariate logistic regression. Restricted cubic spline (RCS) regression tests the nonlinearity of the relationship between obesity measurement indexes and KOA. Subgroup analyses were performed by sex to verify the robustness of the findings.

RESULTS

In this cross-sectional analysis, we found a positive association between obesity measurement indexes and KOA. These results did not change on multiple imputations(BMI: OR = 1.02, 95% CI, 1.01-1.04, P < 0.05; WHtR: OR = 2.85, 95% CI, 1.08-7.51, P < 0.05; BRI: OR = 1.07, 95% CI, 1.01-1.12, P < 0.05; BFP: OR = 1.02 95% CI, 1.00-1.03, P < 0.05). All the effects of obesity measurement indexes with KOA are present in females. None of the stratifying variables significantly affected the association between obesity measurement indexes and KOA. RCS regression test revealed the linear positive correlation between obesity measurement indexes and KOA.

CONCLUSION

In this cross-sectional study, we found a significant association between obesity measurement indexes and KOA. This relationship is not affected by stratification and confounding factors.

Differences in self-reported signs related to central sensitization and pressure pain threshold related to knee osteoarthritis and sarcopenia

PURPOSE

Neuroinflammation, which occurs in knee osteoarthritis and sarcopenia, has attracted attention as a mechanism of central sensitization, but the relationship between central sensitization and these conditions has not been widely studied. This study investigates differences in self-reported signs of central sensitization and pressure pain threshold in individuals with knee osteoarthritis and sarcopenia.

METHODS

We examined 340 patients (mean age ± standard deviation: 76 ± 5.9, women were 86.9%) with knee osteoarthritis scheduled to undergo total knee arthroplasty. For comparison, 129 community-dwelling older people (mean age ± standard deviation: 76 ± 5.5, women were 68.9%) individuals without a history of knee osteoarthritis or any other diagnosed illnesses were matched for age and sex. We assessed central sensitization inventory-9, pressure pain threshold, pain-related factors, skeletal muscle mass index, and hand grip strength. ANCOVA using 2 (patients with knee osteoarthritis and community older people without knee osteoarthritis) × 2 (sarcopenia and robust) was performed to assess outcome measurements.

RESULTS

The prevalence of sarcopenia among patients with knee osteoarthritis was 50.3%. ANCOVA revealed an interaction effect for the central sensitization inventory-9. For the main effect of knee osteoarthritis, there was a significant difference in central sensitization inventory-9, and for the main effect of sarcopenia, there was a significant difference in pressure pain threshold.

CONCLUSIONS

Discrepancies in the evaluation of central sensitization were identified between knee osteoarthritis and sarcopenia. Individuals with knee osteoarthritis had elevated score of self-reported indications of central sensitization, whereas sarcopenic patients had reduced pressure pain thresholds.

Obesity aggravates the role of C-reactive protein on knee pain: A cross-sectional analysis with NHANES data

OBJECTIVE

To examine the relationship between C-reactive protein (CRP) and knee pain, and further explore whether this association is mediated by obesity.

METHODS

The population was derived from 1999 to 2004 National Health and Nutrition Examination Survey. Logistic regression was used to analyze the relationship between CRP and knee pain in three different models, and the linear trend was analyzed. A restricted cubic spline model to assess the nonlinear dose-response relationship between CRP and knee pain. Mediation analyses were used to assess the potential mediating role of obesity. Subgroup analyses and sensitivity analyses were performed to ensure robustness.

RESULTS

Compared with adults with lower CRP (first quartile), those with higher CRP had higher risks of knee pain (odds ratio 1.39, 95% confidence interval 1.12-1.72 in third quartile; 1.56, 1.25-1.95 in fourth quartile) after adjusting for covariates (except body mass index [BMI]), and the proportion mediated by BMI was 76.10% (p < .001). BMI and CRP were linear dose-response correlated with knee pain. The odds ratio for those with obesity compared with normal to knee pain was 2.27 (1.42-3.65) in the first quartile of CRP, 1.99 (1.38-2.86) in the second, 2.15 (1.38-3.33) in the third, and 2.92 (1.72-4.97) in the fourth.

CONCLUSION

Obesity mediated the systemic inflammation results in knee pain in US adults. Moreover, higher BMI was associated with higher knee pain risk in different degree CRP subgroups, supporting an important role of weight loss in reducing knee pain caused by systemic inflammation.

Associations between chronic widespread pain, pressure pain thresholds, leptin, and metabolic factors in individuals with knee pain

OBJECTIVE

The aim was to study associations between chronic widespread pain, widespread pain sensitivity, leptin, and metabolic factors in individuals with knee pain. A secondary aim was to study these associations in a subgroup of individuals with normal BMI.

METHOD

This cross-sectional study included 265 individuals. The participants were categorised into three different pain groups: Chronic widespread pain (CWP), chronic regional pain (ChRP), or no chronic pain (NCP). The pressure pain thresholds (PPTs) were assessed using computerised pressure algometry. Low PPTs were defined as having PPTs in the lowest third of all tender points. Leptin and metabolic factors such as BMI, visceral fat area (VFA), lipids, and glucose were also assessed.

RESULT

Sixteen per cent reported CWP, 15% had low PPTs, and 4% fulfilled both criteria. Those who fulfilled the criteria for CWP were more often women, more obese, and had increased leptin levels. In logistic regression, adjusted for age and gender, leptin was associated with fulfilling criteria for CWP, OR 1.015 (95% CI 1.004-1.027, p = 0.008). In logistic regression, adjusted for age and gender, leptin was associated with low PPTs, OR 1.016 (95% CI 1.004-1.029, p = 0.012). Leptin was also associated with fulfilling both criteria, adjusted for age, sex, and visceral fat area (VFA), OR 1.030 (95% CI 1.001-1.060), p = 0.040.

CONCLUSION

Leptin was associated with fulfilling the combined criteria for chronic widespread pain and low PPTs, even after adjusting for the visceral fat area (VFA). Longitudinal studies are needed to study the causal relationships between leptin and the development of widespread pain.

TRIAL REGISTRATION

clinicalTrials.gov Identifier: NCT04928170.

Assessment of Pain in Osteoarthritis of the Knee

Knee osteoarthritis (KOA) pain is a subjective and personal experience, making it challenging to characterise patients' experiences and assess their pain. In addition, there is no global standard for the assessment of pain in KOA. Therefore, this article examines the possible methods of assessing and characterising pain in patients with KOA using clinical symptoms, pain assessment tools, and imaging. We examine the current methods of assessment of pain in KOA and their application in clinical practice and clinical trials. Furthermore, we explore the possibility of creating individualised pain management plans to focus on different pain characteristics. With better evaluation and standardisation of pain assessment in these patients, it is hoped that patients would benefit from improved quality of life. At the same time, improvement in pain assessment would enable better data collection regarding symptom response in clinical trials for the treatment of osteoarthritis.

Bone-patellar tendon-bone autograft and female sex are associated with the presence of cyclops lesions and syndrome after anterior cruciate ligament reconstruction

PURPOSE

Associated risk factors for the development of cyclops lesions have been little. Investigated, because most previous studies have limited their research to cases with symptomatic cyclops lesions (cyclops syndrome). The purpose of this study was to evaluate the presence of cyclops lesions using magnetic resonance image (MRI) at 6 and 12 months after anterior cruciate ligament reconstruction (ACL-R), and to investigate the associated risk factors of cyclops lesions and syndrome.

METHODS

A retrospective analysis of patients who underwent ACL-R using bone-patellar tendon-bone (BTPB) or hamstring tendon autograft from 2008 to 2017 was conducted. Predictor variables (age, sex, body mass index [BMI], time from injury to ACL-R, preinjury Tegner activity score, graft, meniscal and cartilage injury, and notch width index on MRI for the presence of cyclops lesions and syndrome were analyzed with multivariate logistic regression.

RESULTS

Four hundred and fifty-five patients (225 males and 230 females) were enrolled. One hundred and four patients (22.9%) had cyclops lesions, and all cyclops lesions were detected on MRI at 6 months post-operatively. In addition, 20 patients (4.4%) had cyclops syndrome which means that these were symptomatic cases. The risk factors for presence of cyclops lesions were BPTB autograft (OR = 2.85; 95% CI 1.75-4.63; P < 0.001) and female sex (OR = 2.03; 95% CI 1.27-3.25; P = 0.003). The presence of cyclops syndrome increased with graft (BPTB) (OR = 18.0; 95% CI 3.67-88.3; Powered by Editorial Manager^® and ProduXion Manager^® from Aries Systems Corporation P < 0.001), female sex (OR = 3.27; 95% CI 1.07-10.0; P = 0.038), and increased BMI (OR = 1.21; 95% CI 1.05-1.39; P = 0.008).

CONCLUSIONS

All cyclops lesions were detected 6 months after ACL-R, and the majority of them were asymptomatic. BPTB autograft and female sex were the significant risk factors for the presence of cyclops lesions and syndrome. In addition, increased BMI was associated with a higher risk of developing cyclops syndrome. When BPTB autograft is used for a female patient, full active knee extension should be encouraged in the early period after ACL-R to prevent cyclops lesion formation.

LEVEL OF EVIDENCE

Level IV, retrospective case series.

Relationship Between Knee Biomechanics and Pain in People With Knee Osteoarthritis: A Systematic Review and Meta-Analysis

OBJECTIVE

Our primary aim was to determine the cross-sectional relationship between knee biomechanics during gait and pain in people with medial knee osteoarthritis. Our secondary aim was to evaluate differences in knee biomechanics between symptomatic and asymptomatic participants with medial knee osteoarthritis.

METHODS

Four online databases were searched from inception to July 2021. Eligible studies included people with medial/nonspecific knee osteoarthritis and a reported relationship between knee biomechanics during gait and pain or biomechanics of symptomatic and asymptomatic participants. Two reviewers independently extracted data and evaluated risk of bias. Random-effects meta-analyses were performed when three or more studies reported the same biomechanical variable for pooling (knee adduction moment [KAM], KAM impulse, varus thrust, and peak knee flexion moment [KFM]).

RESULTS

Forty studies were included. Methodological quality ranged from 4 to 9/10. Forty-seven unique biomechanical variables were reported. For the KAM, there was no correlation with pain for peak values pooled (early stance and overall) (r = 0.00, 95% confidence interval [95% CI]: -0.12, 0.11, k = 16), a small negative correlation for early stance peak alone (r = -0.09, 95% CI -0.18, -0.002, k = 12), and a medium positive correlation for the overall peak during stance (r = 0.30, 95% CI 0.17, 0.42, k = 4). Metaregression identified that body mass index moderated the peak KAM-pain relationship (P < 0.001). KAM impulse had a small positive correlation with pain (r = 0.23, 95% CI 0.04, 0.40, k = 5), and people with varus thrust had 3.84 greater odds of reporting pain compared with people without (95% CI 1.72, 8.53, k = 3). Meta-analyses for the peak KFM and pain correlation and secondary aim were nonsignificant.

CONCLUSION

Some knee gait biomechanics were associated with pain in this cohort. Longitudinal studies are required to determine causality.

Cohort profile: the Halland osteoarthritis (HALLOA) cohort-from knee pain to osteoarthritis: a longitudinal observational study in Sweden

PURPOSE

The overall objective in this study is to investigate the early development of radiographic knee osteoarthritis (OA) and its association with hand or/and knee OA, metabolic diseases, biomarkers, chronic pain, physical function and daily physical activity types.

PARTICIPANTS

The Halland osteoarthritis (HALLOA) cohort is a longitudinal cohort study that includes individuals with knee pain in the southwest of Sweden. Enrolment took place from 2017 to 2019. The inclusion criteria were current knee pain, with no former known radiographic knee OA and no cruciate ligament rupture or rheumatological disorder. The participants were recruited: (1) when seeking care for knee pain in primary healthcare or (2) by advertisements in local newspapers. There are 306 individuals included in the study, mean age (SD) 51.7 (8.7) years and 69% are women. The baseline and follow-ups include clinical tests, radiographical examinations, blood samples, metabolic measures, pain pressure thresholds, tests of physical functions, daily physical activity types and patient-reported outcomes.

FINDINGS TO DATE

There were associations between metabolic factors and radiographic knee OA, even in those with normal body mass index at baseline. In addition, clinical hand OA was positively associated with fasting plasma glucose. We also found that modifiable factors as increased visceral fat and total body fat were associated with increased pain sensitivity among individuals with knee pain.

FUTURE PLANS

By studying possible pathophysiological mechanisms of OA over time, we aim to provide new insights on OA progression, identify usable preventive measures helping the clinicians in the management of the disease and improve health for the patients. It is also important to study the development of chronic pain in OA, to get tools to identify individuals at risk and to be able to offer them treatment.

TRIAL REGISTRATION NUMBER

ClinicalTrials.gov (NCT04928170).

Experiences of How Health and Lifestyle among Individuals with Knee Pain Have Been Influenced during the COVID-19 Pandemic, a HALLOA Study

The COVID-19 pandemic has affected the health and lifestyles of both the general population and of vulnerable groups. Individuals with knee pain are recommended to lead an active lifestyle to relieve pain but find it difficult to maintain health and lifestyle compared to the general population due to the cause of chronic pain, impaired physical function, and a diminished quality of life. This study aimed to explore experiences of how health and lifestyle among individuals with knee pain have been influenced during the COVID-19 pandemic. Interviews (n = 19) were conducted in 2021 and analysed with qualitative content analysis. The results showed how individuals with knee pain adjusted their behaviour and revalued their life to maintain health and lifestyle during COVID-19. Adjusted behaviours emerged, such as spending more time at home, becoming digital, and spending more time outdoors, while revaluing life emerged as having a positive outlook on life and sharing responsibility. In conclusion, behaviour was adjusted, and life revalued to manage health and lifestyle during the pandemic. However, the findings are probably similar to the general population, i.e., individuals with knee pain live similar lives as the general population despite knee pain. The results may contribute to alternative ways of maintaining health and lifestyle in various vulnerable groups and may be applied in situations other than the pandemic.

Effect of Neuromuscular Electrical Stimulation During Walking on Pain Sensitivity in Women With Obesity With Knee Pain: A Randomized Controlled Trial

OBJECTIVE

To assess the extent to which pain sensitivity is altered in women with obesity with frequent knee symptoms who walk with either a hybrid training system (HTS) that provides antagonist muscle electrical stimulation vs sensory transcutaneous electrical nerve stimulation (TENS).

DESIGN

Randomized, double-blinded, controlled trial.

SETTING

University-based fitness center.

PARTICIPANTS

Twenty-eight women (N=28) with obesity, aged 40-70 years, with daily knee symptoms.

INTERVENTIONS

Participants were randomized to 12 weeks of biweekly 30-minute walking exercise with either HTS (HTSW group) or sensory TENS (control group).

MAIN OUTCOME MEASURES

Pressure pain thresholds (PPTs) at the more symptomatic knee (local PPT) and PPT at the ipsilateral pain-free wrist (remote PPT).

RESULTS

After adjustment for preintervention values and body mass index (BMI), there was a statistically significant improvement in local PPT in the HTSW group compared with the control group (P=.039). After adjustment for pretraining value, age, and BMI, changes in remote PPT when comparing groups did not reach statistical significance, although the HTS group tended to demonstrate increased remote PPT (P=.052) compared with the control group. Moreover, after adjustment for pretraining value, knee pain, and quality of life, comparing groups did not reach statistical significance, although the HTS group tended to demonstrate decreased knee pain (P=.069) compared with the control group.

CONCLUSIONS

Augmentation of walking exercise with HTS was more effective than application of sensory TENS in improving local pain sensitivity at the knee but not at the wrist in women with obesity with frequent knee symptoms.