Quantitative sensory testing as an assessment tool to predict the response to standard pain treatment in knee osteoarthritis: a systematic review and meta-analysis

Pain profiles and variability in temporal summation of pain and conditioned pain modulation in pain-free individuals and patients with low back pain, osteoarthritis, and fibromyalgia

BACKGROUND

Pain profiles (e.g. pro- and anti-nociceptive) can be developed using quantitative sensory testing (QST) but substantial variability exists. This study describes the variability in temporal summation of pain (TSP) and conditioned pain modulation (CPM) in chronic musculoskeletal pain patients, proposes cut-off values, and explores the association with clinical pain intensity.

METHODS

This is a secondary analysis in which TSP and CPM were assessed using cuff algometry in pain-free subjects (n = 69), and patients with chronic low back pain (cLBP, n = 267), osteoarthritis (n = 134), and fibromyalgia (n = 101). Using TSP and CPM from the pain-free subjects as a reference, four distinct pain profiles TSP (low/high) and CPM (low/high) were created, and differences in clinical pain between pain profiles were explored.

RESULTS

Individual data revealed large inter-person variability. High TSP and low CPM were found in fibromyalgia (p < 0.01) and osteoarthritis (p < 0.01) but not cLBP when compared to pain-free subjects. The proportion of patients classified into the distinct pain profiles was significantly different (p < 0.001) with the largest proportion in the high TSP and low CPM group in fibromyalgia (52.5%) and osteoarthritis (41.4%). Clinical pain was not significantly different comparing the pain profiles, and no significant correlations were observed between clinical pain and TSP or CPM.

CONCLUSION

These results demonstrated substantial inter-person variability in TSP and CPM in patients with different chronic pain conditions and pain-free subjects. The proportion of patients with a pro-nociceptive profile appears larger in fibromyalgia and osteoarthritis, but we found no association to clinical pain.

SIGNIFICANT STATEMENT

This analysis shows that there is variability when assessing TSP and CPM in both pain-free subjects and patients with chronic pain. A cut-off for determining when a person is pain-sensitive is proposed, and data based on this cut-off approach suggest that significantly more patients with osteoarthritis and fibromyalgia are pain-sensitive (i.e. higher TSP and lower CPM) compared to pain-free subjects. This analysis does not find an association between pain sensitivity and clinical pain.

Early CRPS Is a Heterogeneous Condition: Results From a Latent Class Analysis

BACKGROUND

Complex regional pain syndrome (CRPS) is a debilitating condition characterised by significant heterogeneity. Early diagnosis is critical, but limited data exists on the condition's early stages. This study aimed to characterise (very) early CRPS patients and explore potential subgroups to enhance understanding of its mechanisms.

METHODS

A total of 113 early CRPS patients were recruited, with 89 undergoing physical assessments. Data included demographic information, work-related factors, CRPS history and clinical features, body perception disturbances, quantitative sensory testing (QST), and a visuospatial attention task.

RESULTS

QST identified deficits in detecting thermal and mechanical stimuli, alongside increased sensitivity to thermal and blunt pressure painful stimuli. Participants reported body perception disturbances similar to those of persistent CRPS. Visuospatial biases were observed in two subgroups of patients. Latent class analysis (LCA) of 85 participants, based on five clinical parameters, identified four profiles: Mild, Moderate, Body Representation Disturbance (BRD), and Pressure Allodynia CRPS. The Mild and Moderate profiles were associated with higher-intensity trauma, with the latter showing worse outcomes. BRD and Pressure Allodynia CRPS followed mild trauma but exhibited the poorest outcomes. BRD CRPS displayed significant body perception disturbances, while Pressure Allodynia CRPS presented the highest sensitivity to pressure and psychosocial risk of chronification. Neither condition duration nor skin temperature effectively distinguished subgroups.

CONCLUSIONS

These findings emphasise the heterogeneity within (very) early CRPS patients and support the absence of a minimum required duration prior to the CRPS diagnosis. Central/systemic mechanisms may play critical roles in severe cases.

SIGNIFICANCE

This study identifies distinct (very) early CRPS profiles, suggesting different pathophysiological mechanisms and challenging traditional classifications. It paves the way for improved diagnosis and tailored treatments.

Association of autoimmune diseases with the occurrence of osteoarthritis: a gene expression and Mendelian randomization study

Background

Observational studies have indicated a potential association between autoimmune diseases and the occurrence of Osteoarthritis (OA), with an increased risk of mortality among affected patients. However, whether a causal relationship exists between the two remains unknown.

Methods

In the Mendelian randomization (MR) study, we accessed exposure Genome-wide association study (GWAS) data from both the MRC Integrative Epidemiology Unit (MRC-IEU) and the FinnGen consortium. GWAS data for OA were obtained from MRC-IEU. We employed univariable, multivariable, and reverse MR analyses to explore potential associations between autoimmune disorders and OA. Additionally, a two-step mediation MR analysis was performed to investigate indirect factors possibly influencing the relationship between autoimmune disorders and OA. Afterward, we conducted an observational analysis to further explore the relationship between autoimmune disease and occurrence as well as of OA using a real-world database (the MIMIC-IV database). Based on public gene expression sequencing data, we further explored the potential shared pathogenesis between autoimmune diseases and OA.

Results

In our univariable MR study, we identified five autoimmune diseases that are associated with OA. These include Celiac disease (OR = 1.061, 95% CI = 1.018-1.105, p = 0.005), Crohn's disease (OR = 1.235, 95% CI = 1.149-1.327, p = 9.44E-09), Ankylosing spondylitis (OR = 2.63, 95% CI = 1.21-5.717, p = 0.015), RA (OR = 1.082, 95% CI = 1.034-1.133, p = 0.001), and Ulcerative colitis (OR = 1.175, 95% CI = 1.068-1.294, p = 0.001). In the mediation effect analysis, it was found that there is no correlation between cytokines and autoimmune diseases and OA. Based on transcriptome data analysis, it was found that metabolism-related pathways play a key role in the co-morbidity of autoimmune diseases and OA.

Conclusion

Our findings revealed that genes associated with Celiac disease, Crohn's disease, Ankylosing spondylitis, RA, and Ulcerative colitis were independently linked to the development of OA. Furthermore, we conducted an analysis of potential pathogenic genes between these diseases and OA, offering a novel approach for the simultaneous treatment of multiple conditions.

Quantitative sensory testing, psychological factors, and quality of life as predictors of current and future pain in patients with knee osteoarthritis

ABSTRACT

Substantial interindividual variability characterizes osteoarthritis (OA) pain. Previous findings identify quantitative sensory testing (QST), psychological factors, and health-related quality of life as contributors to OA pain and predictors of treatment outcomes. This exploratory study aimed to explain baseline OA pain intensity and predict OA pain after administration of a nonsteroidal anti-inflammatory drug in combination with paracetamol for 3 weeks. The Knee Injury and Osteoarthritis Outcome Score (KOOS) pain score was used to estimate OA pain presentation. One hundred one patients were assessed at baseline and follow-up using QST (pressure pain thresholds and temporal summation of pain [TSP]), symptoms of depression and anxiety, pain catastrophizing scales (PCSs), and health-related quality of life. Linear regression with backward selection identified that PCS significantly explained 34.2% of the variability in baseline KOOS pain, with nonsignificant contributions from TSP. Pain catastrophizing score and TSP predicted 29.3% of follow-up KOOS pain, with nonsignificant contributions from symptoms of anxiety. When assessed separately, PCS was the strongest predictor (32.2% of baseline and 24.1% of follow-up pain), but QST, symptoms of anxiety and depression, PCS, and quality of life also explained some variability in baseline and follow-up knee OA pain. Further analyses revealed that only TSP and PCS were not mediated by any other included variables, highlighting their role as unique contributors to OA pain presentation. This study emphasizes the importance of embracing a multimodal approach to OA pain and highlights PCS and TSP as major contributors to the baseline OA pain experience and the OA pain experience after OA treatment.

Prognostic value of preoperative mechanical hyperalgesia and neuropathic pain qualities for postoperative pain after total knee replacement

BACKGROUND

Total knee replacement (TKR) is the gold standard treatment for end-stage chronic osteoarthritis pain, yet many patients report chronic postoperative pain after TKR. The search for preoperative predictors for chronic postoperative pain following TKR has been studied with inconsistent findings.

METHODS

This study investigates the predictive value of quantitative sensory testing (QST) and PainDETECT for postoperative pain 3, 6 and 12 months post-TKR. We assessed preoperative and postoperative (3 and 6 months) QST measures in 77 patients with knee OA (KOA) and 41 healthy controls, along with neuropathic pain scores in patients (PainDETECT). QST parameters included pressure pain pressure threshold (PPT), pain tolerance threshold (PTT), conditioned pain modulation (CPM) and temporal summation (TS) using cuff algometry, alongside mechanical hyperalgesia and temporal summation to repeated pinprick stimulation.

RESULTS

Compared to healthy controls, KOA patients at baseline demonstrated hyperalgesia to pinprick stimulation at the medial knee undergoing TKR, and cuff pressure at the calf. Lower cuff algometry PTT and mechanical pinprick hyperalgesia were associated with preoperative KOA pain intensity. Moreover, preoperative pinprick pain hyperalgesia explained 25% of variance in pain intensity 12 months post-TKR and preoperative neuropathic pain scores also captured 30% and 20% of the variance in postoperative pain at 6 and 12 months respectively. A decrease in mechanical pinprick hyperalgesia from before surgery to 3 months after TKR was associated with lower postoperative pain at the 12 months post-TKR follow-up.

CONCLUSION

Our findings suggest that preoperative pinprick hyperalgesia and neuropathic-like pain symptoms show predictive value for the development of chronic post-TKR pain.

SIGNIFICANCE STATEMENT

This study's findings hold significant implications for chronic pain management in knee osteoarthritis patients, particularly those undergoing total knee replacement surgery (TKR). Mechanical hyperalgesia and neuropathic pain-like characteristics predict postoperative pain 1 year after TKR, emphasizing the importance of understanding pain phenotypes in OA for selecting appropriate pain management strategies. The normalization of hyperalgesia after surgery correlates with better long-term outcomes, further highlighting the therapeutic potential of addressing abnormal pain processing mechanisms pre- and post-TKR.

Mechanical hyperalgesia and neuropathic pain qualities impart risk for chronic postoperative pain after total knee replacement

Total knee replacement (TKR) is the gold-standard treatment for end-stage chronic osteoarthritis pain, yet many patients report chronic postoperative pain after TKR. The search for preoperative predictors for chronic postoperative pain following TKR has been studied with inconsistent findings. This study investigates the predictive value of quantitative sensory testing (QST) and PainDETECT for postoperative pain 3, 6, and 12 months post-TKR. We assessed baseline and postoperative (3- and 6-months) QST measures in 77 patients with knee OA (KOA) and 41 healthy controls, along with neuropathic pain scores in patients (PainDETECT). QST parameters included pressure pain pressure threshold (PPT), pain tolerance threshold (PTT), conditioned pain modulation (CPM), and temporal summation (TS) using cuff algometry, alongside mechanical hyperalgesia, and mechanical temporal summation to repeated pinprick stimulation. Compared to healthy controls, KOA patients at baseline demonstrated hyperalgesia to pinprick stimulation at the medial OA-affected knee and cuff pressure on the ipsilateral calf. Lower cuff algometry PTT and mechanical pinprick hyperalgesia were associated with baseline KOA pain intensity. Moreover, baseline pinprick pain hyperalgesia explained 25% of variance in pain intensity 12 months post-TKR and preoperative neuropathic pain scores also captured 30% and 20% of the variance in postoperative pain at 6- and 12-months, respectively. A decrease in mechanical pinprick hyperalgesia from before surgery to 3 months after TKR was associated with lower postoperative pain at the 12 months post-TKR follow-up, and vice-versa. Our findings suggest that preoperative pinprick hyperalgesia and PainDETECT neuropathic-like pain symptoms show predictive value for the development of chronic post-TKR pain.