**5. Treatment options**

subacromial arthritis (acetabulization); and Grade 4B, glenohumeral arthritis with subacromial arthritis (Grade 4 of Hamada et al.). These subtypes allowed for more specific classifica-

CT scan was the original investigation described by Goutallier in assessment of fatty atrophy, and can still be used for patients where any bony changes need to be more accurately determined and the state of muscle wasting and atrophy. Goutallier et al. classified muscle quality by the amount of fatty infiltration in the rotator cuff muscle as identified on CT in the axial plane, with a thorough analysis of the whole muscle belly [16]. They graded muscular fatty degeneration into 5 stages: Stage 0 is a normal muscle with no fatty infiltration and stage 1 is a muscle in which some fatty streaks can be seen on CT. Stage 2 is a muscle with substantial fatty atrophy but still affecting less than 50% of visible muscle. In stages 3 and 4 fatty atrophy affects 50% and over 50% of muscle respectively [16]. According to various authors fatty muscle infiltration beyond Goutallier stage 2 represents a non-functional muscle belly making

One of the most common imaging modalities for assessing the rotator cuff is magnetic resonance imaging (MRI). It can reliably identify and characterize the rotator cuff tendon tears [27]. MRI scan is easier to read in assessing the size of any rotator cuff tear and both muscle wasting and fatty atrophy, but patients with sore shoulders may struggle to stay still for the duration of the scan which may take 45 min. With the growing popularity of magnetic resonance imaging Goutallier classification was adapted to MRI. Some authors correlated it with surgical outcomes and retear rates [10] and found that like for CT the advanced degree of fatty infiltration (over 2 Goutallier) on preoperative MRI was a strong predictive factor of cuff repair failure [10].

It is worth remembering that for MRI, the Goutallier scoring uses a different plane compared to CT. It is no longer the axial plane but the most lateral parasagittal image on which the scapular spine is still in contact with the scapular body (Y view) [28]. This makes the method prone to false interpretation in cases of massive cuff tears, because severe muscle-tendon retraction can cause bunching of the muscle that may actually create an illusion of a larger muscle belly than in reality [10]. Some authors reported the use of so-called 'tangent sign' [29] as an indicator of advanced fatty infiltration [30] and as a predictor of whether a rotator cuff tear will be reparable [31]. A tangent sign is positive when atrophied supraspinatus muscle falls below a tangent line drawn between superior border of coracoid process and superior margin of scapular spine. This is assessed, just like Goutallier score, on the most lateral MRI image on which both coracoid process and scapular spine are still in contact with scapular body [32]. However a recent study by Kim et al. showed that tangent sign alone was not a good predictive indicator of outcome of massive cuff repair. According to authors the single most predictive factor of successful repair in MRCT remains infraspinatus fatty infiltration <3 according to Goutallier [32]. Another important diagnostic modality is a ultrasound scan, which has become a popular modality for evaluating rotator cuff pathology because of its low cost and reliability in identifying the presence of a tear and its size even during the postoperative period [10]. Unfortunately ultrasound cannot penetrate through bone and may not provide accurate information about large rotator cuff tears where the tendon edges have retracted medial to the lateral acromial border [33]. Its optimal use is also notoriously dependent on the technician's experience.

tion of patients and almost all patients could be classified [26].

104 Advances in Shoulder Surgery

a successful repair of its tendon virtually impossible [1, 16].
