Pressure-pain threshold algometric measurement in patients with greater trochanteric pain after total hip arthroplasty.
ABSTRACT The evaluation of tenderness associated with greater trochanteric pain (GTP) syndrome is amenable to bias and depends on the examiner's experience. In this study, we tested whether the use of an electronic pressure algometer enhanced the reliability of this evaluation.
Pressure-pain threshold (PPT) was measured with an electronic algometer in 18 patients who developed GTP after total hip arthroplasty and in matched controls. Both groups were evaluated with visual analog scale.
The PPT measurements showed large interindividual variability across patients. The correspondence of the PPT measurements in asymptomatic patients was good. We found good validity for the algometer used. The PPT ratio of 0.8 (affected vs. unaffected side) can be used as a cut-off ratio. The PPT measurements at the greater trochanter (local pain) were significantly lower than at the ilio-tibial band (radiated pain). There was no correlation between PPT measurements and visual analog scales. Despite the acceptable sensitivity and specificity of pressure algometer, because of low positive predictive value and large interindividual variability, pressure algometer has a limited value as a screening test.
The examination of tenderness associated with GTP is facilitated by the used algometer. It is the intraindividual body-side PPT differences that yield the most sensitive measurement for the assessment of deep pain. A cut-off value of 0.8 can be used for diagnostic purposes. Interindividual differences might be considerable and could mask pathologic diagnostic findings.
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ABSTRACT: Introduction Experimental pain studies can provide unique insight into the dimensions of pain and into individual differences in pain responsiveness by controlling different aspects of pain-eliciting stimuli and pain measures. In experimental pain studies, pain responsiveness can be assessed as pain threshold, pain tolerance or pain ratings. The test-theoretical qualities of these different measures, however, have not yet been completely documented. In the current study, several of these qualities were investigated in a pain experiment applying different algometric techniques. The objective of the study was to investigate the reliability (test–retest) and the convergent validity (correspondence) of the different methods found in the literature of measuring pressure-pain threshold, and the interrelationship between pressure-pain threshold, pressure-pain tolerance, and pressure-pain ratings. Methods Sixty-six healthy female subjects were enrolled in the study. All pressure stimuli were applied by a trained investigator, using a digital algometer with a 1 cm2 rubber tip. Pressure-pain thresholds were assessed repeatedly on six different body points (i.e. left and right calf one third of total calf muscle length below the popliteal space), the lower back (5 cm left and right from the L3), and left and right forearm (thickest part of brachioradialis muscle). Next, pressure-pain tolerance was measured on the thumbnail of the non-dominant hand, followed by rating affective and sensory components (on visual analogue scales) of a stimulus at tolerance level. Last, affective and sensory ratings were obtained for two pressure intensities. Results With intraclass correlations above .75 for pain responses per body point, test–retest reliability was found to be good. However, values obtained from all first measurements were significantly higher as compared with the two succeeding ones. Convergent validity of pain thresholds across different body points was found to be high for all combinations assessed (Cronbach's alpha values >.80), but the highest for bilateral similar body parts (>.89). Finally, principal components analysis including measures of threshold, tolerance and pain ratings yielded a three-factor solution that explained 81.9% of the variance: Moderate-level stimulus appraisal & pain tolerance; Pain threshold; Tolerance-level stimulus appraisal. Conclusion and implications Findings of the current study were used to formulate recommendations for future algometric pain studies. Concerning pressure-pain threshold, it is recommended to exclude first measurements for every body point from further analyses, as these measurements were found to be consistently higher compared with the following measurements. Further, no more than two consecutive measurements (after the first measurement) are needed for a reliable mean threshold value per body point. When combining threshold values of several body points into one mean-aggregated threshold value, we suggest to combine bilateral similar points, as convergent validity values were highest for these combinations. The three-factor solution that was found with principal components analyses indicates that pressure-pain threshold, subjective ratings of moderate intensity stimuli, and subjective ratings of the maximum (tolerance) intensity are distinct aspects of pain responsiveness. It is therefore recommended to include a measure of each of these three dimensions of pain when assessing pressure pain responsiveness. Some limitations of our study are discussed.Scandinavian Journal of Pain 01/2012; 3(1):31-37.
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ABSTRACT: Various treatments are available for reducible unstable fractures of the distal radius, such as closed reduction combined with fixation by external fixator (EF), and rigid internal fixation using a locked volar plate (VP). Although there are studies comparing these methods, there is no conclusive evidence indicating which treatment is best. The hypothesis of this study is that surgical treatment with a VP is more effective than EF from the standpoint of functional outcome (patient-reported).Methods/design: The study is randomized clinical trial with parallel groups and a blinded evaluator and involves the surgical interventions EF and VP. Patients will be randomly assigned (assignment ratio 1:1) using sealed opaque envelopes. This trial will include consecutive adult patients with an acute (up to 15 days) displaced, unstable fracture of the distal end of the radius of type A2, A3, C1, C2 or C3 by the Arbeitsgemeinschaft fur Osteosynthesefragen-Association for the Study of Internal Fixation classification and type II or type III by the IDEAL32 classification, without previous surgical treatments of the wrist. The surgical intervention assigned will be performed by three surgical specialists familiar with the techniques described. Evaluations will be performed at 2, and 8 weeks, 3, 6 and 12 months, with the primary outcomes being measured by the Disabilities of the Arm, Shoulder and Hand (DASH) questionnaire and measurement of pain (Visual Analog Pain Scale and digital algometer). Secondary outcomes will include radiographic parameters, objective functional evaluation (goniometry and dynamometry), and the rate of complications and method failure according to the intention-to-treat principle. Final postoperative evaluations (6 and 12 months) will be performed by independent blinded evaluators. For the Student's t-test, a difference of 10 points in the DASH score, with a 95% confidence interval, a statistical power of 80%, and 20% sampling error results in 36 patients per group. Results from this study protocol will improve the current evidence regarding to the surgical treatment these fractures.Trial registration: ISCRTN09599740.BMC Musculoskeletal Disorders 03/2014; 15(1):65. · 1.88 Impact Factor
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ABSTRACT: On the basis of our experience in the application of the mechanical algometer and a number of pilot experiments, we speculated that 0.1- and 0.01-cm(2) probes might improve the measurement of mechanical pain sensitivity relative to the conventional 1-cm(2) probe. Here, we examined the accuracy, feasibility, and applicability of these probes in detecting the mechanical pain sensitivity. Mechanical pain threshold and tolerance tests were performed on subjects using the three probes of 1, 0.1, and 0.01 cm(2) in random order. We compared the application of these probes. The study was set at the Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China. Fifty healthy male Han Chinese subjects were recruited. We compared the qualities of stimulus-evoked pain, test stability, the measuring time, the subjects' acceptance level of the procedure, the validity of pain measurement, and the arduousness of the task for the investigator among the three different size probes. Compared with the conventional 1-cm(2) probe, the 0.01- and 0.1-cm(2) probes resulted in the subjects responding to stimulus-evoked pain more quickly, accurately, and consistently, and also made the measurement more comfortable for investigators. Up to 80% of the subjects reported the pain quality as a pricking sensation when the 0.01-cm(2) probe was used. The use of the 0.1-cm(2) probe might be more suitable as an optimized method for the detection of pressure pain sensitivity in clinical studies. In addition, the 0.01-cm(2) probe could potentially serve as an alternative to the weighted needle pinprick, providing continuous quantizing detection for pricking pain sensitivity.Pain Medicine 10/2013; · 2.46 Impact Factor