The presence of active myofascial trigger points in the supraspinatus, sternocleidomastoid, anterior deltoid, levator scapulae, latissimus dorsi, and/or infraspinatus muscles may represent a reliable criteria for the diagnosis of myofascial pain syndrome (MPS), according to a study published in Pain Medicine.
A physical therapist with experience in diagnosing and treating MPS recruited 20 patients with MPS and 20 healthy control patients. Study participants with MPS had ≥1 active myofascial trigger point in ≥1 of the 10 muscles designated for study.
Muscles of interest included the splenius capitis, sternocleidomastoid, upper trapezius, levator scapulae, infraspinatus, supraspinatus, anterior deltoid, latissimus dorsi, teres major, and pectoralis major. Also, patients with MPS were included in the study if they had a history of regional pain. The frequency of agreements between 2 separate examiners on whether participants could be diagnosed as having MPS was the study’s primary outcome.
Very good interexaminer reliability was found for accurate MPS diagnosis (Cohen’s coefficient, κ, 1.0) and for the identification of affected muscles (κ, 0.81). The best results were found for the supraspinatus (κ, 1), anterior deltoid (κ, 0.92), sternocleidomastoid (κ, 0.96), levator scapulae (κ, 0.88), latissimus dorsi (κ, 0.77), and infraspinatus (κ, 0.77) muscles. A greater percentage of study participants with MPS vs healthy control patients reported pain referral (5.6% vs 2%, respectively; P <.0001) and experienced muscle strength limited by pain (2% vs 0.1%, respectively; P <.0001). Both sensitivity and specificity were high for the majority of tests used for the clinical examination of each muscle, confirming the validity of the clinical criteria for MPS diagnosis.
Of the 2 investigators in this study, 1 was blinded to the diagnosis group. The blinded investigator was aware of the number of participants in each group, which may have presented judgement bias during enrollment. Most of the muscles examined in this study are superficial, which could represent additional bias in this study, particularly in reliability.
The investigators suggest future trials are warranted to evaluate “the validity of the clinical diagnostic criteria of [myofascial trigger points] as compared with a gold standard such as needle electromyography, and in different body regions.”
Mayoral Del Moral O, Torres Lacomba M, Russell IJ, Sánchez Méndez Ó, Sánchez B. Validity and reliability of clinical examination in the diagnosis of myofascial pain syndrome and myofascial trigger points in upper quarter muscles [published online December 15, 2017]. Pain Med. doi: 10.1093/pm/pnx315