Levator Scapulae Stiffness Measurement Reliability in Individuals with and without Chronic Neck Pain by Experienced and Novel Examiners.

The levator scapulae muscle is a key structure in the etiopathology of neck and shoulder musculoskeletal pain. Although previous studies used shear-wave elastography (SWE) for characterizing this muscle elasticity, limited evidence assessed the inter-examiner reliability of this procedure. This study aimed to analyze the inter-examiner reliability for calculating Young's modulus and shear wave speed in a cohort of participants with and without chronic neck pain. A diagnostic accuracy study was conducted, acquiring a set of SWE images at the C5 level in participants with and without neck pain (n = 34 and 33, respectively) by two examiners (one experienced and one novel). After blinding the participants' identity, examiner involved, and side, the stiffness indicators were calculated by an independent rater in a randomized order. Intra-class correlation coefficients (ICC), standard error of measurement, minimal detectable changes, and coefficient of variation were calculated. Both cohorts had comparable sociodemographic characteristics (p > 0.05). No significant levator scapulae elasticity differences were found between genders, sides, or cohorts (all, p > 0.05). Inter-examiner reliability for calculating Young's modulus and shear wave speed was moderate-to-good for assessing asymptomatic individuals (ICC = 0.714 and 0.779, respectively), while poor-to-moderate in patients with neck pain (ICC = 0.461 and 0.546, respectively). The results obtained in this study support the use of this procedure for assessing asymptomatic individuals. However, reliability estimates were unacceptable to support its use for assessing elasticity in patients with chronic neck pain. Future studies might consider that the shear wave speed is more sensitive to detect real changes in comparison with Young's modulus.

Pressure pain hypersensitivity and referred pain from muscle trigger points in elite male wheelchair basketball players.

BACKGROUND: Shoulder injuries are common in individuals who use wheelchairs. OBJECTIVES: This study investigated the presence of mechanical pain hypersensitivity and trigger points in the neck-shoulder muscles in elite wheelchair basketball players with/without shoulder pain and asymptomatic able-bodied elite basketball players. METHODS: Eighteen male wheelchair basketball players with shoulder pain, 22 players without shoulder pain, and 20 able-bodied elite male basketball players were recruited. Pressure pain thresholds were assessed over C5-C6 zygapophyseal joint, deltoid muscle, and second metacarpal. Trigger points in the upper trapezius, supraspinatus, teres minor, infraspinatus, teres major, latissimus dorsi, subscapularis, pectoralis minor, pectoralis major and deltoid muscles were also examined. RESULTS: Wheelchair basketball players with shoulder pain showed lower pressure pain thresholds over the C5-C6 joint and second metacarpal than elite wheelchair basketball players without pain (between-groups differences: 1.1, 95%CI 0.4, 1.8 and 1.8, 95%CI 0.8, 2.8, respectively) and able-bodied basketball players without pain (between-groups differences: 0.8, 95%CI 0.4, 1.2; 1.6, 95%CI 0.8, 2.4, respectively). The mean number of myofascial trigger points for wheelchair basketball players with unilateral shoulder pain was 4.8±2.7 (2±1 active, 2.9±2.2 latent). Wheelchair basketball players and able-bodied basketball players without shoulder pain exhibited a similar number of latent trigger points (2.4±2.0 and 2.4±1.8, respectively). Wheelchair basketball players with shoulder pain exhibited higher number of active myofascial trigger points than those without pain (either with or without wheelchair), but all groups had a similar number of latent trigger points (P<0.05). CONCLUSIONS: The reported mechanical pain hypersensitivity suggests that active trigger points may play a role in the development of shoulder pain in elite male wheelchair basketball players.