Differences In Pressure Pain Thresholds Research Articles

Pressure algometry in the general adult population: Age and sex differences.

Experimental pain studies have revealed inter-individual variations in pain perception that are influenced by age, sex, and country of origin. This study aimed to explore the age and sex differences in pressure pain thresholds within the Iranian general population. To assess the pressure pain thresholds, a handheld pressure algometer was applied bilaterally to the middle fingers of both hands. The participants also completed the short form of the McGill Pain Questionnaire to provide a clinical pain rating. This cross-sectional study included 1610 adult subjects (54.96% female, mean age 40.13 ± 10.18 years). The findings indicated that females generally exhibited lower pain thresholds than males when assessing pain detection and tolerance parameters (P < .001). Females also demonstrated a significant lower pressure thresholds and clinical pain ratings compared with men (P < .001). Additionally, significant differences were observed between age groups in terms of pain detection and tolerance thresholds (P = .02 and P = .03, respectively). However, the interaction between sex and age was not significant. No significant differences in pain detection thresholds were observed between the right and left hand (P = .11). This study underscores the potential utility of algometry as a valuable tool for objectifying pain in the Iranian population.

Sex-Based Differences in Pressure Pain Thresholds of Myofascial Trigger Points in Cervical and Cranial Muscles in Tension-Type Headache: A Cross-Sectional Study

Sex-Based Differences in Pressure Pain Thresholds of Myofascial Trigger Points in Cervical and Cranial Muscles in Tension-Type Headache: A Cross-Sectional Study

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

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. 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. 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. 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.

No Evidence of Short-Term Changes in Muscle Activity Elicited by Dry Needling in Chronic Unilateral Shoulder Pain Patients.

The aim of the study was to assess short-term changes in shoulder muscle activity elicited by dry needling in chronic unilateral shoulder pain patients. A double-blind, placebo-controlled clinical trial was conducted, in which 30 volunteers with unilateral shoulder pain (USP) were recruited and randomly assigned to either real or sham dry needling conditions. Pain intensity scores, pressure pain threshold (PPT), glenohumeral internal rotation angles, and electromyographic activity during isotonic shoulder tasks (shoulder flexion and extension) were assessed before, immediately and 72 h after the intervention in the infraspinatus and deltoid muscles. A single application of real dry needling resulted in lower pain intensity scores and a larger range in glenohumeral internal rotation 72 h after the intervention in comparison with sham dry needling. No differences in PPT or muscle activity were observed due to the intervention. A single application of real dry needling resulted in clinically significant changes in the short-term. No differences were detected in muscle activation in the infraspinatus or deltoid muscles. Complementary interventions and longer follow-up times may be required to observe changes in muscle activity.

Effects of multidirectional elastic tape on pain and function in individuals with lateral elbow tendinopathy: A randomised crossover trial

Objective To investigate the effects of multidirectional elastic tape on pain and function in individuals with lateral elbow tendinopathy. Study Design Randomised crossover trial. Setting Biomechanics laboratory. Subjects 27 participants (11 females, mean (SD) age: 48.6 (11.9) years) with clinically diagnosed lateral elbow tendinopathy of at least six weeks’ duration. Interventions Tensioned multidirectional elastic tape applied over the wrist, compared to control tape (untensioned), and no tape conditions. Main measures Pain-free grip strength and pressure pain threshold were recorded at three timepoints for each condition: baseline, post-application, and following an exercise circuit. Change scores were calculated as the post-application or post-exercise value minus baseline. Repeated-measure analyses of variance were used to examine differences between conditions. Results There were no statistically significant differences in pain-free grip strength between conditions (flexed position: F2,52 = 0.02, p = 0.98; extended position: F2,52 = 2.26, p = 0.12) or across timepoints (post-application vs post-exercise) (flexed position: F1,26 = 0.94, p = 0.34; extended position: F1,26 = 0.79, p = 0.38). Seven participants (26%) increased pain-free grip strength above the minimal detectable change following application of multidirectional elastic tape. There were no statistically significant differences in pressure pain threshold between conditions (affected lateral epicondyle: F1.51,39.17 = 0.54, p = 0.54) or across timepoints (affected lateral epicondyle: F1,26 = 0.94, p = 0.34). Conclusion Tensioned multidirectional elastic tape may not immediately improve pain-free grip strength or pressure pain threshold in our lateral elbow tendinopathy population; however, individual variation may exist.

Effects of Intraoperative Opioid Administration on Postoperative Pain and Pain Threshold: A Randomized Controlled Study.

Fentanyl and short-acting remifentanil are often used in combination. We evaluated the effect of intraoperative opioid administration on postoperative pain and pain thresholds when the two drugs were used. Patients who underwent gynecological laparoscopic surgery were randomly assigned into two groups (15 patients each) to receive either sufficient (group A) or minimum (group B) fentanyl (maximum estimated effect site concentration: A: 7.86 ng/mL, B: 1.5 ng/mL). The estimated effect site concentration at the end of surgery was adjusted to the same level (1 ng/mL). Patients in both groups also received continuous intravenous remifentanil during surgery. The primary outcome was the pressure pain threshold, as evaluated by a pressure algometer 3 h postoperatively. The pressure pain threshold at 3 h postoperatively was 51.1% (95% CI: [44.4–57.8]) in group A and 56.6% [49.5–63.6] in group B, assuming a preoperative value of 100% (p = 0.298). There were no significant differences in pressure pain threshold and numeric rating scale scores between the groups after surgery. The pain threshold decreased significantly in both groups at 3 h postoperatively compared to preoperative values, and recovered at 24 h. Co-administration of both opioids caused hyperalgesia regardless of fentanyl dose.

The Differing Effects of Nociception and Pain Memory on Pain Thresholds in Participants with and without a History of Injury: A Pretest-Posttest Quasi Experimental Study

Purpose: Memory has been identified as an important protective feature to prevent future injury, but its role has yet to be ascertained. The current study aimed to determine whether there was a difference in pressure pain threshold (PPT) responses between participants with a prior history of injury of lower extremity injury (PSI) and those without (NPSI) when exposed to 1) experimental mechanical pain, 2) short-term memory recall of a painful stimulus, or 3) long-term memory of the pain associated with a prior injury. Subjects and Methods: The study used a pretest-posttest quasi-experimental design. A convenience sample of 59 pain-free participants was recruited from an urban university. Twenty-nine PSI and 30 NPSI were stratified into two groups based on their injury history with PPT values measured at baseline and immediately following each of the three experimental conditions. A repeated measure ANCOVA analysis was conducted for each condition to determine whether there was a difference in PPT responses between the two groups. Results: There was a statistically significant difference in PPT values between the two groups when exposed to experimental pain, F(1,57) = 6.010, p = 0.017, partial η2 = 0.095 and with long-term pain memory, F(1,57) = 4.886, p = 0.031, partial η2 = 0.079. There was no statistically significant difference between groups with short-term pain memory, F(1,57) = 3.925, p = 0.052, partial η2 = 0.064. Conclusions: These findings suggest that pain processing may be altered by pain memory, highlighting the role of experience and memory in the rehabilitation process.

Patients with symptomatic permanent atrial fibrillation show quantitative signs of pain sensitisation

Abstract Background/Introduction Most patients with atrial fibrillation (AF) report symptoms, while around one-third are asymptomatic. We hypothesized that sensory processing, in particular pain, differs in patients with symptomatic and asymptomatic AF. Purpose To assess differences in pain sensitisation in patients with symptomatic and asymptomatic AF. Methods Thirty individuals with permanent AF (15 symptomatic, 15 asymptomatic) completed the AF6 and SF-36 questionnaires and underwent quantitative pain sensitisation testing using pressure algometry at the sternum (referred pain area) and the tibialis anterior muscle (generalized pain area). The primary objective was to assess differences in pressure pain thresholds (PPT), temporal summation of pain (TSP), and conditioned pain modulation (CPM) in the two groups. The secondary objective was to determine association of demographic and clinical parameters to quantitative measures of pain sensitisation. Results The symptomatic group had lower PPTs at both tibialis (p=0.004) and sternum (p=0.01), as well as impaired CPM (p=0.025) and facilitated TSP (p=0.008) at the tibialis but not sternum, compared to the asymptomatic group. The AF6 sum score was negatively correlated to PPT on both tibialis (r=−0.50, p=0.005) and sternum (r=−0.42, p=0.02) and positively correlated to TSP of both tibialis (r=0.57, p=0.001) and sternum (r=0.45, p=0.01), but not to CPM. The physical component summary score was positively correlated to the PPT on both tibialis (r=0.52, p=0.003) and sternum (r=0.40, p=0.03) and negatively to TSP on the tibialis (r=−0.53, p=0.003) but not sternum. Conclusions Patients with symptomatic AF exhibit lower pain tolerance than patients with asymptomatic AF, as well as impaired pain inhibitory control and facilitated summation of pain, indicating that pain sensitisation may be of importance in symptomatic AF. Funding Acknowledgement Type of funding sources: Public hospital(s). Main funding source(s): Department of Cardiology, Örebro University, Sweden PPTs tibialis anterior musclePPTs sternum

The Effects of Gender, Functional Condition, and ADL on Pressure Pain Threshold in Stroke Patients

BackgroundSomatosensory impairments and pain are common symptoms following stroke. However, the condition of perception and pain threshold for pressure stimuli and the factors that can influence this in individuals with stroke are still unclear. This study aimed to investigate the gender differences in pressure pain threshold (PPT) and positive somatosensory signs for pressure stimuli, and explore the effects of joint pain, motor function, and activities of daily living (ADL) on pain threshold in post-stroke patients.DesignA cross-sectional study.MethodsA total of 60 participants with stroke were recruited, and their pain condition, motor functions, and ADL were evaluated by the Fugl-Meyer assessment of joint pain scale, motor function scale, and Barthel index, respectively. PPTs in eight tested points at the affected and unaffected sides were assessed.ResultsSignificant differences in PPTs were found between male and female patients in all measured muscles (p < 0.05). Positive somatosensory signs for pressure stimuli, including hypoalgesia and hyperalgesia, were frequently found at the affected side, particularly in the extremity muscles, but such signs were not significantly influenced by gender (p > 0.05). More equal PPTs between both sides and relatively lower PPTs at the affected side in the trunk and medial gastrocnemius muscles (p < 0.05) were observed in patients with less pain, better motor functions, and ADL.ConclusionGender differences widely exist in post-stroke survivors either at the affected or unaffected side, which are multifactorial. Sensory loss and central and/or peripheral sensitization, such as hypoalgesia and hyperalgesia for pressure stimuli, caused by a brain lesion are common signs in male and female stroke patients. Moreover, patients who are in a better condition show a more symmetrical pain sensitivity between both sides in the trunk and in female lower extremities, indicating the bidirectional improvement of somatosensory abnormalities caused by a possible neural plasticity.

Patients with symptomatic permanent atrial fibrillation show quantitative signs of pain sensitisation

ObjectiveMost patients with atrial fibrillation (AF) report symptoms, while one-third are asymptomatic. We hypothesised that sensory processing, in particular pain, differs in patients with symptomatic and asymptomatic AF.MethodsThirty individuals with...

Pain sensitivity and shoulder function among breast cancer survivors compared to matched controls: a case-control study

ObjectivePersistent pain and loss of shoulder function are common adverse effects to breast cancer treatment, but the extent of these issues in comparison with healthy controls is unclear for survivors beyond 1.5 years after treatment. The purpose of this study was to benchmark differences in pressure pain thresholds (PPT), maximal isokinetic muscle strength (MIMS), and active range of motion (ROM) of females with persistent pain ≥1.5 years after breast cancer treatment (BCS) compared with pain-free matched controls (CON), and examine the presence of movement-evoked pain (MEP) during assessment of MIMS.MethodsThe PPTs of 18 locations were assessed using a pressure algometer and a numeric rating scale was used to assess intensity of MEP. Active ROM and MIMS were measured using a universal goniometer and an isokinetic dynamometer, respectively.ResultsA two-way analysis of variance revealed that PPTs across all locations, MIMS for horizontal shoulder extension/flexion and shoulder adduction, active ROM for shoulder flexion, horizontal shoulder extension, shoulder abduction, and external shoulder rotation were significantly lower for BCS compared with CON (P < 0.05). MEP was significantly higher for BCS and MEP intensity had a significant, negative correlation with PPTs (P < 0.01).Discussion/conclusionBCS with persistent pain ≥1.5 years after treatment demonstrates widespread reductions in PPTs and movement-specific reductions in MIMS and active ROM of the affected shoulder, along with MEP during physical performance assessment.Implications for cancer survivorsBCS with persistent pain ≥1.5 years after treatment shows signs of central sensitization and may benefit from individualized rehabilitation.

High Rate of Pain Sensitization in Musculoskeletal Shoulder Diseases: A Systematic Review and Meta-analysis.

Pain sensitization, defined as an increased responsiveness of nociceptive neurons to normal input, is detected in several musculoskeletal diseases, but there are no systematic reviews or meta-analyses about pain sensitization in shoulder pain. The aim of the study was to document pain sensitization rate and its impact in patients with shoulder pain. PubMed, Cochrane Library, and Web of Science were searched on January 8, 2020. Level I-IV studies, evaluating pain sensitization in musculoskeletal shoulder disorders through validated methods (questionnaires/algometry) were included. The primary outcome was pain sensitization rate. Secondary outcomes were the pain sensitivity level measured as pressure pain threshold, temporal summation, conditioned pain modulation, and suprathreshold heat pain response. Associated demographic and psychosocial factors were evaluated. The rate of abnormal pressure pain threshold in patients with shoulder pain varied from 29% to 77%. Questionnaires detected pain sensitization in 11% to 24% of patients. This meta-analysis showed no difference in pressure pain threshold and central pain modulation but documented a significant difference in terms of suprathreshold heat pain response, indicating a hypersensitivity state in patients with shoulder pain versus asymptomatic controls. The only factor that was constantly found to correlate with higher sensitivity was a lower postoperative outcome. Pain sensitization has a high rate among patients with musculoskeletal shoulder pain, regardless of the specific etiology, and this may lead to worse clinical outcome after treatment of the primary disease. The best way to assess pain sensitization still needs to be identified as the assessment methods results in used high variability in the documented pain sensitization rate.

Evidence of Widespread Mechanical Hyperalgesia but Not Exercise-Induced Analgesia in Athletes With Mild Patellar Tendinopathy Compared With Pain-Free Matched Controls: A Blinded Exploratory Study.

The aim of the study was to assess centrally induced pain processing with pressure pain thresholds bilaterally and remotely in active volleyball and basketball athletes with mild patellar tendinopathy compared with asymptomatic control athletes. Secondary objective was to explore the role of exercise-induced analgesia during a training session in athletes with patellar tendinopathy. In this exploratory study, pressure pain thresholds of 21 patellar tendinopathy athletes and 16 age- and sex-matched asymptomatic team members were measured by a blinded assessor bilaterally on the patellar tendon and unilaterally on the elbow extensor tendon with a pressure algometer before, during, and after a regular training session. Patellar tendinopathy athletes had a significantly higher average body mass index compared with asymptomatic athletes (mean difference 1.75 kg/m2; 95% confidence interval = 0.35-3.15, P = 0.02). At baseline, athletes with patellar tendinopathy showed lowered pressure pain thresholds in the affected knee (P = 0.001), unaffected knee (P < 0.001), and elbow (P = 0.01) compared with controls. No clear patterns were identified to explain between-group differences in pressure pain thresholds before, during, and after exercise. This exploratory study found primary and secondary mechanical hyperalgesia in athletes with patellar tendinopathy compared with asymptomatic athletes. Further research is required on the effects of an acute exercise bout on pain thresholds in this population.

The effect on clinical outcomes when targeting spinal manipulation at stiffness or pain sensitivity: a randomized trial

The mechanisms underlying pain relief following spinal manipulative therapy (SMT) are not understood fully although biomechanical and neurophysiological processes have been proposed. As such, we designed this randomized trial to elucidate the contributions of biomechanical and neurophysiological processes. A total of 132 participants with low back pain were randomly assigned to receive SMT at either the lumbar segment measured as the stiffest or the segment measured as having the lowest pain threshold. The primary outcome was patient reported low back pain intensity following treatment. Secondary outcomes were biomechanical stiffness and neurophysiological pressure pain threshold. All outcomes were measured at baseline, after the fourth and final session and at 2-weeks follow-up. Data were analyzed using linear mixed models, and demonstrated that the SMT application site did not influence patient reported low back pain intensity or stiffness. However, a large and significant difference in pressure pain threshold was observed between groups. This study provides support that SMT impacts neurophysiological parameters through a segment-dependent neurological reflex pathway, although this do not seem to be a proxy for improvement. This study was limited by the assumption that the applied treatment was sufficient to impact the primary outcome.

Pain threshold in the masticatory and cervical muscles in different types of temporomandibular disorders

Introduction: Given the intimate connection of the temporomandibular joint in the cervical region and its functions of chewing, speech and swallowing, patients with temporomandibular disorders (TMD) have most painful condition in stomathognatic muscles. Objective: Check for differences in pressure pain threshold of the masseter (MS), temporalis (TM), upper trapezius (UT) and sternocleidomastoid (SCM) muscles in different types of TMD. Method: Participated in the research 97 subjects, classified according to “The Research Diagnostic Criteria for Temporomandibular Disorders (RDC/TMD)”: myofascial pain (TMD IA), myofascial pain with limited opening (TMD IB), disc displacement with reduction (TMD IIA), disc displacement without reduction and with limited opening (TMD IIB), disc displacement without reduction and without limited opening (TMD IIC). For measurement of the pressure pain threshold (PPT) was used the pressure algometry program (Kratos) of the TM, MS, UT and SCM muscles. For statistical analysis was used the Graphpad Instat program with the Kruskal-Wallis test. Results: The sample consisted of 67 women and 30 men with an average age of 22.09 ± 5.45 years. Of these subjects, 40 were classified as “with TMD”, 57 as “without TMD”, 34 as “TMD IA”, 16 as “TMD IB”, 14 as “TMD IIA” and nobody as “TMD IIB” and “TMD IIC”. The MS, TM and UT muscles showed decreased threshold in myogenic groups of TMD with relation to the group without TMD. Only the masseter muscle showed statistical significance when compared to the myogenic groups with each other, demonstrating that the IB group has lower PPT. Individuals with TMD IB showed lower PPT of MS, TM and UT muscles when compared to TMD IIA. Conclusion: There is a significant difference comparing the PTT of MS, TM and UT muscles of myofascial pain subgroup to the subgroup without TMD. There were differences between the groups myogenic in PPT of MS. TMD IB showed lower threshold in TMD IB group than in TMD IIA group. Controversially, it was not observed when comparing the SCM muscle and disc displacement subgroup with the subgroup without TMD.

Effect of Body Mass Index on Primary Dysmenorrhea and Daily Activities in Adolescents

Abstract Background: Primary dysmenorrhea is the most prevalent menstrual problem in young females, which affects their daily activities and quality of life. Although some studies have demonstrated an association between BMI and the incidence and severity of dysmenorrhea, this relationship is still contro-versial. Aim of Study: To investigate the effect of body mass index on primary dysmenorrhea and daily activities in adolescents. Subjects and Methods: A correlational study involved 100 adolescent girls, selected from Beni-Mazar Secondary School throughout the period from March 2019 to August 2019. Their age ranged from 16 to 25 years. Subjects were classified into 4 groups equally according to body mass index. Pain intensity was measured using numeric pain scale, pressure pain threshold using pressure algometer and daily activities using daily activities questionnaire. Results: The study findings revealed that there was a significant difference in the numeric pain scale between groups (p=0.001), there was a significant difference in pressure pain thresholds between groups (p=0.0001) and there was no significant difference in the daily activities between groups (p=0.17) except for school absenteeism and social activity there was a significant difference (p=0.001), (p=0.006) re-spectively. Conclusion: The difference in body mass index had an effect on primary dysmenorrhea; both obese and underweight subjects suffer from primary dysmenorrhea more than subjects with normal weight and overweight, there was no difference on daily activities except for school absenteeism and social activity had higher percentage in obese and underweight.

Bilateral sensory and motor as well as cognitive differences between persons with and without musculoskeletal disorders of the wrist and hand.

BackgroundSensory and motor disturbances are characteristic of musculoskeletal injuries and conditions. Rehabilitation interventions aimed at remediating these disturbances are traditionally exclusively targeted to the affected area. However, there is some evidence of bilateral changes in sensory and motor function associated with unilateral injuries and conditions suggesting central changes. Deficits on specific cognitive tasks have also been documented in persons with chronic pain. PurposeThe purpose of the present study was to determine if participants with unilateral pain arising from heterogeneous wrist/hand injuries and conditions demonstrate bilateral changes in sensory and motor functions as well as cognitive deficits. Design/methodsSensory (Pressure Pain Thresholds, Two Point Orientation Discrimination), Motor (grip strength and Purdue Pegboard), and Cognitive function (Stroop test and mental rotation task) were measured in 30 participants with wrist/hand pain and 30 healthy control participants in an observational cross-sectional study. ResultsParticipants with unilateral wrist/hand pain demonstrated differences in cognitive function measured with the Stroop test (p = 0.03). They also demonstrated bilateral sensorimotor differences in pressure pain thresholds (p = 0.03), grip strength (p = 0.00) and Purdue pegboard test (p = 0.03) results compared to healthy control participants. ConclusionCognitive as well as bilateral alterations in sensory and motor function in participants with musculoskeletal injuries and conditions suggest central changes are involved in their pathophysiology. These findings in persons with heterogeneous injuries/conditions suggest that these changes are not specific to an injury/condition. Bilateral sensorimotor changes have important implications with regards to the pathophysiology of musculoskeletal disorders of the wrist/hand, for rehabilitative interventions and research.

Pressure Pain Thresholds In Adults With Patellofemoral Pain And Patellofemoral Joint Osteoarthritis: A Case-Control Study

Background/Aims Patellofemoral pain and patellofemoral joint osteoarthritis are common non-self-limiting conditions. The two conditions are on a continuum with 20–30% of patellofemoral pain patients showing radiographic and magnetic resonance imaging features of patellofemoral joint osteoarthritis. Evidence suggests reduced pressure pain thresholds, locally and remotely from the site of reported pain, are a feature of patellofemoral pain in adolescent females. However, a paucity of evidence exists for male and female adults with no studies considering pressure pain thresholds in patellofemoral joint osteoarthritis. Exploring if pain sensitisation is a dominant feature of patellofemoral pain and patellofemoral joint osteoarthritis, and if a subgroup at and increased risk can be identified, may guide future treatments for instance the need for components aimed at neurological pain. The primary aim is to measure local and remote pressure pain thresholds in patellofemoral pain and patellofemoral joint osteoarthritis patients compared to matched controls. Secondary aims will consider the relationship between pressure pain thresholds and patellofemoral pain/patellofemoral joint osteoarthritis severity and knee function. Methods A total of 13 patellofemoral pain patients, 15 patellofemoral joint osteoarthritis patients and 54 age and sex matched controls were recruited from UK male and female adults. Demographic details, Tegner activity level score, symptom duration, Kujala score (for patellofemoral pain severity), Knee injury and Osteoarthritis Outcome Score score (for patellofemoral joint osteoarthritis severity) and Whatman score rating of five single leg squats (for knee function) were recorded. Pressure pain thresholds were measured at six sites: five local around the knee, one remote on the contralateral leg. Between-group differences were tested using analysis of variance techniques. Strength of association between pressure pain thresholds and patellofemoral pain/patellofemoral joint osteoarthritis severity and knee function were tested using Spearman's rank order correlation. Results No statistically significant difference in pressure pain thresholds were identified between the patellofemoral pain patients and matched controls (F(1,31)=0.687, P=0.413, h2=0.022). Similarly, no difference in pressure pain thresholds were identified between the patellofemoral joint osteoarthritis patients and matched controls (F(1,47)=0.237, P=0.629, h2=0.005). Conclusions Contrary to the hypothesis, no difference was found between patellofemoral pain nor patellofemoral joint osteoarthritis patients and matched controls.

No difference in pressure pain threshold and temporal summation after lumbar spinal manipulation compared to sham: A randomised controlled trial in adults with low back pain

BackgroundChanges in quantitative sensory tests have been observed after spinal manipulative therapy (SMT), particularly in pressure pain thresholds (PPT) and temporal summation (TS). However, a recent systematic review comparing SMT to sham found no significant difference in PPT in patients with musculoskeletal pain. The sham-controlled studies were generally low quality, and conclusions about other quantitative sensory tests could not be made. ObjectivesWe aimed to perform a sham-controlled study with the specific objective of investigating changes in PPT and TS short-term after lumbar SMT compared to sham manipulation in people with low back pain. MethodsThis was a double-blind randomised controlled trial comparing high-velocity low-amplitude lumbar SMT against sham manipulation in participants with low back pain. Primary outcome measures were PPT at the calf, lumbar spine and shoulder, and TS at the hands and feet. These were measured at baseline, then immediately, 15 min and 30 min post-intervention. ResultsEighty participants (42 females) were included in the analyses (mean age 37 years), with 40 participants allocated to each intervention group. Significant between-group differences were only observed for calf PPT, which could be explained by a decrease in PPT (increased sensitivity) after SMT and an increase after sham. Feet TS decreased significantly over time after both SMT and sham, and any other changes over time were inconsistent. ConclusionsOur results suggest that lumbar SMT does not have a short-term hypoalgesic effect, as measured with PPT and TS, when compared to sham manipulation in people with low back pain.

Neuropathic-Like Pain Symptoms in a Community-Dwelling Sample with or at Risk for Knee Osteoarthritis.

To characterize neuropathic-like pain among individuals with or at risk for knee osteoarthritis. One hundred eighty-four individuals who self-identified as non-Hispanic black or non-Hispanic white and presented with unilateral or bilateral knee pain. Neuropathic-like pain was assessed using the painDETECT, and those with high vs low neuropathic-like pain were compared on clinical pain, psychological symptoms, physical function, and quantitative sensory testing. Analyses were unadjusted, partially and fully adjusted for relevant covariates. Thirty-two (17.4%) participants reported experiencing neuropathic-like pain features above the painDETECT clinical cut-score. The neuropathic-like pain group reported significantly greater pain severity on all measures of clinical pain and higher levels of psychological symptoms when fully adjusted for covariates, but no differences emerged for disability and lower extremity function. The neuropathic-like pain group also reported greater overall heat pain ratings during the heat pain threshold and increased temporal summation of heat pain in the fully adjusted model. Additionally, those with neuropathic-like pain symptoms reported greater painful after-sensations following heat pain temporal summation in all analyses. No significant group differences in pressure pain threshold emerged at any of the testing sites. In contrast, temporal summation of mechanical pain was significantly greater at both the index knee and the ipsilateral hand for the neuropathic-like pain group in all analyses. Participants with or at risk for knee osteoarthritis who reported high neuropathic-like pain experienced significantly greater clinical pain and increased heat and mechanical temporal summation at the index knee and other body sites tested, suggesting central sensitization.