When compared to magnetic resonance imaging (MRI), ultrasound (US) performed by experienced users is an inexpensive tool that has good sensitivity and specificity for diagnosing rotator cuff (RC) tears. However, many practitioners are now utilizing in-office US with little to no formal training as an adjunct to clinical evaluation. The objective of our study was to determine if US without formal training is effective in managing patients with a suspected RC tear.
This was a single-centre prospective observational study. Five fellowship-trained surgeons each examined 50 participants referred for a suspected RC tear (n= 250). Patients were included if = 40 years old, had an MRI of their affected shoulder, had failed conservative treatment of at least 6 months, and had ongoing pain and disability. Patients were excluded if they had glenohumeral instability, evidence of major joint trauma, or osteonecrosis. After routine clinical exam, surgeons recorded their treatment plan (“No Surgery”, “Uncertain”, or “Surgery”). Surgeons then performed an in-office diagnostic US followed by an MRI and documented their treatment plan after each imaging study. Agreement between US and MRI was evaluated for the rotator cuff muscles and biceps..
Following clinical assessment, the treatment plan was recorded as “No Surgery” in 90 (36%), “Uncertain” in 96 (39%) of cases, “Surgery” in 61 (25%) cases, and incomplete in 3 (2%). In-office US allowed resolution of 66 (69%) of uncertain cases with 199 (81%) of patients having a definitive treatment plan. One hundred-thirteen patients were designated as not requiring surgery based on clinical assessment and US, of which MRI identified pathology warranting surgery (6% of the study sample). MRI resolved 25 of 30 of the remaining 'Uncertain' cases. The positive likelihood ratio (PLR) for supra/infraspinatus for ultrasound versus MRI was 1.27 and negative likelihood ratio (NLR) was 0.45. For subscapularis, PLR was 2.83 and NLR was 0.45. For biceps, the PLR was 3.24 and NLR was 0.41.
In-office ultrasound performed without formal training resulted in moderate capacity to detect rotator cuff and biceps pathology when compared to MRI and was an effective tool for clinical decision-making allowing a diagnosis and treatment plan to be made in over 88% of patients. A small percentage (6%) of patients with surgical pathology including full-thickness rotator cuff tears, larger than expected tears and/or alternate glenohumeral pathology (e.g., labral tear) were missed at initial evaluation using in-office ultrasound.