Researchers question whether MRI findings should be considered pathologic
A study presented at the AAOS Annual Meeting found a high rate of superior glenoid labral tear diagnoses based on magnetic resonance imaging (MRI) in a cohort of middle-aged, asymptomatic people.
The growing incidence of superior labral surgery in the United States in the past decade may be linked to the increasing use of MRI for diagnosis, according to the study’s lead author, Randy Schwartzberg, MD.
“Superior labral tears are diagnosed with a high frequency in patients aged 45 years to 60 years,” noted Dr. Schwartzberg. “It is known from cadaveric studies that degenerative labral tears are seen with increasing age. Our MRI study corroborated this for superior labral tears.
“The findings of our study call into question the clinical relevance of superior labral tears diagnosed by MRI in this patient population,” asserted Dr. Schwartzberg.
Conducting the study
Superior labral injuries in younger people can occur from traumatic injuries and overhead sports, but these injury mechanisms are much less common in middle-aged people.
Dr. Schwartzberg and his fellow researchers shed light on diagnosis of this injury in middle-aged patients by assessing the rate of MRI-diagnosed labral tears in asymptomatic people and also by determining whether MRI results showed any other shoulder abnormalities.
A total of 53 individuals (26 males and 27 females) aged 45 years to 60 years, all of whom had no history of surgery or shoulder injury, participated in the study. Researchers performed physical examinations on all study participants. In addition, each person underwent high field noncontrast MRI on a randomly chosen shoulder.
Two musculoskeletal radiologists, both of whom were blinded to the study’s aims, evaluated each MRI (Table 1). The investigators then statistically analyzed the radiologists’ determinations.
One radiologist diagnosed 72 percent of the cohort with superior labral tears, while the other radiologist diagnosed this lesion in 55 percent of study participants (Fig. 1). Posterior labral tears were also diagnosed at a high rate—55 percent—by one radiologist, but were diagnosed at only 15 percent by the other radiologist.
Other injuries that were diagnosed at much lower rates—11 percent or lower—included anterior labral tears, partial-thickness articular rotator cuff tears, partial bursal rotator cuff tears, and full-thickness rotator cuff tears.
The radiologists demonstrated moderate inter-rate reliability regarding their evaluations of the superior labrum.
“Evaluation of the posterior labrum was the only area where the radiologists demonstrated poor inter-rater reliability,” noted Dr. Schwartzberg. “The reason for this was that one of the radiologists considered the posterior part of the superior labrum to also be part of the posterior labrum.”
The investigators found no differences in the radiologists’ readings for superior labral tears related to gender, shoulder dominance, study subject’s job physicality, or participation in overhead sports.
The radiologists also found abnormalities outside the scope of the five anatomic areas in the shoulder they were asked to assess. One radiologist found rotator cuff calcific tendinopathy in two study participants, while the other radiologist found rotator cuff tendinopathy in only one of those two individuals. In addition, one radiologist identified a study participant as having a paralabral cyst. The other radiologist identified the same paralabral cyst and also noted paralabral cysts in three other people.
Dr. Schwartzberg acknowledged that the study had limitations, including uncertainty regarding “whether the radiologists’ MRI interpretations of superior labral tears are actually tears of the labrum, as arthroscopy was not performed on any of the participants.”
He called for more study to determine whether the MRI findings of superior labral injuries reported in this study may actually be due to a normal aging process that is not yet fully understood.
Dr. Schwartzberg’s coauthors of “High Prevalence of Superior Labral Tears Diagnosed by MRI in Middle-Aged Asymptomatic Shoulders” are Bryan Reuss, MD; Bradd Burkhart, MD; and Matt Butterfield, MD.
One or more of the authors reported potential conflicts of interest. The most current disclosure information may be accessed electronically at www.aaos.org/disclosure
Jennie McKee is a senior science writer for AAOS Now. She can be reached at firstname.lastname@example.org