Evidence for Improvement in Local but Not Diffuse Pressure Pain Thresholds Following Physical Therapist Interventions for Tendinopathy: A Systematic Review

Abstract

AbstractObjectivesThe objectives of this study were to investigate whether quantitative sensory testing proxy measures for peripheral and central sensitization change following physical therapist interventions for tendinopathy and whether changes occur in parallel to changes in self-reported pain.MethodsFour databases—Ovid EMBASE, Ovid MEDLINE, CINAHL Plus, and CENTRAL—were searched from inception to October 2021. Three reviewers extracted data for the population, tendinopathy, sample size, outcome, and physical therapist intervention. Studies that reported quantitative sensory testing proxy measures and pain at baseline and another time point following a physical therapist intervention were included. Risk of bias was assessed using the Cochrane Collaboration’s tools and the Joanna Briggs Institute checklist. Levels of evidence were assessed using the Grading of Recommendations Assessment, Development and Evaluation.ResultsTwenty-one studies were included and all investigated changes in pressure pain threshold (PPT) at either local and/or diffuse sites. Change in other proxy measures of peripheral and central sensitization were not investigated among any studies. Diffuse PPT did not demonstrate significant change in all trial arms that reported this outcome. Local PPT improved for 52% of trial arms, and it was more likely to change at the medium (63%) and longer (100%) compared with the immediate (36%) and short (50%) timepoints. On average, 48% of trial arms demonstrated parallel changes in either outcome. Pain improvement was more frequent than local PPT improvement at all timepoints except for the longest.ConclusionLocal PPT may improve among people receiving physical therapist interventions for tendinopathy, but these changes appear to lag behind changes in pain. Change in diffuse PPT among people with tendinopathy has been infrequently investigated in the literature.ImpactThe findings of the review contribute to knowledge of how tendinopathy pain and PPT change with treatments.