Magnetic resonance arthrography assessment of the superior labrum using the BLC system: age-related changes mimicking SLAP-2 lesions.

Abstract

The purpose of the study was to describe the variation of the superior labrum with increasing age by assessing magnetic resonance (MR) arthrograms. Inclusion criteria were used to include only the MR arthrograms of patients devoid of clinical labral pathology. Two hundred thiry-six MR arthrograms were blindly assessed for biceps-labral complex (BLC) type 1-3 and sublabral recess size by a musculoskeletal radiologist. We have chosen the BLC system, which defines normal superior labral variants, since it is established in the literature and is used by reporting musculoskeletal (MSK) radiologists. The MR arthrograms demonstrated that the majority of patients <40years old were BLC type 1 and showed a steady increase in BLC types 2 and 3 with increasing age. Assessments demonstrated significantly greater (p < 0.01) mean BLC types (1.62 vs 1.29) and recess size (1.35 vs 0.66mm) in those over 40 compared with those less than 40years of age. Furthermore, significant differences (p < 0.05) were noted between mean BLC assessments between different decades of age. There appears to be a physiologic deepening of the superior labrum sulcus with age, which becomes significant after the age of 40. These findings can contribute to whether the superior labrum is considered abnormal when assessed radiographically. The differentiation of normal age-related changes in the shoulder, from those of a type 2 SLAP tear can reduce the rates of unnecessary SLAP-2 repairs. This is the first reported series to use the BLC system; we believe it provides a common nomenclature to allow clear communication between specialists.