Irreparable rotator cuff tears: a novel classification system. 
Irreparable rotator cuff tears can be managed by several approaches.  However, current tear classifications fail to reflect the wide variety of their presentation, which has important clinical and prognostic implications.  We describe a novel classification system based on preoperative imaging findings and intraoperative observation where each cuff tendon (numbered sequentially: 1-supraspinatus, 2-infraspinatus, 3-teres minor, and 4-subscapularis) is assessed intraoperatively for reducibility to the footprint; tendons with reparable lesions are assessed for fatty degeneration (which predicts healing potential) and given a plus if degeneration is <50 % (Fuchs stage I-II/Goutallier stage 0-II) or a minus if it is ≥50 % (Fuchs stage III/Goutallier stage III-IV).  The proposed system (1) allows more consistent and reproducible classification of cuff tears where at least one tendon is irreparable; (2) results in more accurate diagnosis; (3) guides in treatment selection; and (4) ensures better outcomes and realistic patient expectations.  The novel classification system can contribute to develop increasingly exhaustive and reproducible classification models.