Correlation of pain sensitization with muscle strength and angular kinematics in women with patellofemoral pain.

BACKGROUND: Patellofemoral pain has a poor long-term prognosis, which can be explained by a pain sensitization process. The pain sensitization process may be related to the increase of stress in the patellofemoral joint that is already associated with kinematic alterations and weakness in the musculature of the hip and knee. METHODS: Were compared the pressure pain threshold, temporal summation, conditioned pain modulation, angular kinematics, and muscle strength between 26 patellofemoral pain and 24 asymptomatic women and then correlated pain sensitization variables with biomechanical variables in pain group. The pressure pain threshold was determined on seven points of the knee, tibialis anterior muscle, and elbow. Ten consecutive stimuli were performed for temporal summation, and cold water was used as the conditioning stimulus for conditioned pain modulation. The strength of hip and knee muscles was determined using a manual dynamometer. Three-dimensional kinematics were evaluated during the lateral step down, considering peak and excursion values of the movement and the Movement Deviation Profile. FINDINGS: The pressure pain threshold of the elbow (2.13 [1.84-2.41] vs. 1.63 [1.25-2] kg/cm2), all sites of the knee were lower, as well as the Movement Deviation Profile was higher (9.33 [9.20-9.46] vs. 12.43 [12.1-12.75]) in the pain group. No difference in temporal summation, conditioned pain modulation, muscle strength and discrete kinematic values were found. No significant correlation was found between the Movement Deviation Profile and pressure pain threshold. INTERPRETATION: Biomechanical factors, pain processing, and modulation in women with patellofemoral pain, when different from asymptomatic individuals, are not necessarily associated.

High-energy dose of therapeutic ultrasound in the treatment of patellar tendinopathy: protocol of a randomized placebo-controlled clinical trial.

BACKGROUND: Patellar tendinopathy is an extremely debilitating condition and its treatment usually requires a combination of clinical approaches. Therapeutic ultrasound (TUS) is one of the most available electrophysical agent in rehabilitation settings; however, there is also a lack of high-quality studies that test different dosimetric aspects of TUS. Thus, the purpose of this study is to evaluate the short-, medium-, and long-term effects of the combination of high-energy TUS with a rehabilitation program for patellar tendinopathy. METHODS: This will be a randomized, placebo-controlled trial with blinding of patients, assessors, and therapist. The setting is an outpatient physical therapy clinic. We will recruit 66 participants (male and female) aged between 18 and 40 years and presenting with patellar tendinopathy. A treatment combining high-energy dose TUS and a rehabilitation program for patellar tendinopathy will be delivered twice a week for 8 weeks. The control group will receive the same treatment, but with a placebo TUS. The effectiveness of the intervention will be measured at the beginning (baseline), midpoint (4 weeks), and end of treatment (8 weeks), as well as at 3- and 6-months post-treatment. Primary outcomes will be pain intensity (visual analogue scale, VAS), and VISA-P questionnaire and primary time points will be baseline (T0) and the end of the program (T2). Also, IPAQ-short form questionnaire, muscle strength (manual dynamometry), 2D kinematics, pain pressure threshold (PPT) algometry, thermography, and magnetic resonance imaging (MRI) will be collected. DISCUSSION: TUS will be applied in an attempt to enhance the results obtained with the rehabilitation program proposed in this study, as well as stimulate some repair responses in individuals undergoing treatment for patellar tendinopathy, which in turn may optimize and improve treatment programs for patellar tendinopathy as well as to establish new guidelines for the application of TUS. TRIAL REGISTRATION: This study was prospectively registered at April-3rd-2018 and updated at September-1st-2019 in the Brazilian Registry of Clinical Trials (REBEC) under the registration number: RBR-658n6w.