of the Rotator Cuff Tears

Fig. 1

Partial tear. Arthroscopic view from the posterior portal: articular side lesion

Bursal Side Lesions

In the early 1990s, the practice of shoulder arthroscopy was at the beginning stage; nevertheless, Ellman [1] was already able to define the prevalence of the partial lesions both in the bursal and articular side. He stated that the bursal side lesions were clearly less frequent than the articular one. This consideration, that over time was confirmed, represents the background for the modern hypothesis concerning etiopathogenesis of rotator cuff tears. Previously, the attention was focalized on the conflict between the rotator cuff and the coraco-acromial arc; nowadays, the concept that tendon degeneration represents the primum movens of a cuff tear and that the partial tear is more prevalent on the articular side is widely accepted. Codman and Akerson [2] stated that the circular lesion of the supraspinatus tendon might be due to friction phenomena. Yamanaka and Fukuda [6] observed that the prevalence of incomplete lesions in their autoptic survey was 13 % and that only 2.4 % was localized on the bursal side.

Ellman [1] suggests exploring the cuff from the posterior arthroscopic portal in order to correctly identify the lesion and to perform a complete bursectomy (Fig. 2a, b). The “thin strap” tear of the supraspinatus tendon was described by Codman as a multi-stratum lesion whose tendon laminae were parallel to the articular surface. Ellman considered the removal of the antero-inferior aspect of the acromion as the only treatment for this type of lesion.

Fig. 2

(a, b) Partial tear. Arthroscopic view from the posterior portal: bursal side lesions

Intratendinous Tears

The intratendinous tears are those identified by MRI or arthro-MRI [7] but that are not visible either in the articular or in the bursal side during arthroscopic surgery. Codman [2] firstly hypothesized this type of lesion basing his idea exclusively on his clinical and anatomo-pathological findings. If one of the two sides presents a defect, it is correct to consider it as a deep partial lesion involving the articular or the bursal side and not as an intratendinous tear. Many authors proposed suggestions on how to intraoperatively identify the presence of the intratendinous lesion. Gartsman [7] proposed to inject a saline solution or methylene blue into the area where the presence of the intratendinous lesion is suspected. If the lesion is present, tendon tissue would look swollen and eventually stained.

Even the classification of Wasilewski and Frankl [3] considers three lesion groups: lesion visible (A) from the articular side; (B) from both sides; and (C) from the bursal side. However, it is curious to note that of 50 consecutive patients who underwent arthroscopic surgery for suspected lesions of rotator cuff tear and subacromial impingement (clinical and arthrographic diagnosis), 62 % had a partial tear (A = 22 %, B = 36 %; C = 4 %) and only 38 % had a full-thickness tear.

Ellman’s classification [1] suggested classifying partial lesions into three degrees, considering the average thickness of healthy tendon to be about 10–12 mm:

I degree	Depth < 3 mm
II degree	3 < Depth < 6 mm (or involving less than a half tendon)
III degree	Depth > 6 mm (or involving more than a half tendon)

A further classification was proposed by Gartsman’s [7]:

I degree	Less than 1/4 of the tendon thickness is involved
II degree	Less than a half of the tendon thickness is involved
III degree	More than a half of the tendon thickness is involved

Of partial lesions, those belonging to I, II, and III degrees occurred, respectively, in 45, 40, and 15 % of cases.

Snyder [8] divided partial lesions into two categories, the articular (A) and the bursal (B) types; each of the two categories is further divided into five subcategories (Table 1):

Table 1

Snyder classification for partial lesions [8]

	Articular side (A) and bursal side (B) lesions
0	Normal rotator cuff with synovitis and/or bursitis
I	Slight inflammation with no lesion of the tendons
II	Slight degeneration of the tendon, without flap
III	Degeneration and fragmentation of the tendon, good quality of the tendon tissue
IV	Wide lesion with degeneration and fragmentation of the tendon or flap with two tendons involved

For greater simplicity, the five subcategories (0–IV) can be divided into two groups:

Group of minimal lesions: including subcategories 0, I, and II. According to the author, these lesions do not require specific treatment except for a slight debridement and/or acromioplasty.
Group of complex lesions: including subcategories III and IV. The repair of the lesion with the trans-tendon technique or arthroscopic tear completion and repair are the recommended treatments. Tears A3 or A4, involving the supraspinatus tendon, are identified by the author with the acronym PASTA (Partial Articular Supraspinatus Tendon Avulsion) lesion.

In 2008, Habermayer and colleagues [9] proposed a new classification of the partial articular side lesion, because, according to the authors, previous Ellman [1] and Snyder [8] classifications do not provide information on the lesion depth on the coronal (Fig. 3) and sagittal (Fig. 4) plane nor they are related to their etiology and pathomorphology.

Fig. 3

Habermeyer et al.’s classification of the partial lesions. Extension of articular-sided supraspinatus tendon tear in coronal plane. (a) Type 1 tear. Small tear within transition zone from cartilage to bone. (b) Type 2 tear. Extension of tear up to center of footprint. (c) Type 3 tear. Extension of tear up to greater tuberosity

Fig. 4

Habermeyer et al.’s classification of the partial lesions. Extension of articular-sided supraspinatus tendon tear in transverse plane. (a) Type A tear. Tear of coracohumeral ligament continuing into medial border of supraspinatus tendon. (b) Type B tear. Isolated tear within crescent zone. (c) Type C tear. Tear extending from lateral border of pulley system over medial border of supraspinatus tendon up to area of crescent zone

On the coronal plane, lesions are divided into:

Type 1	Small tear within transition zone from cartilage to bone
Type 2	Extension of tear up to center of footprint
Type 3	Extension of tear up to greater tuberosity

On the sagittal plane, the classification includes three types of lesions:

Type A	Tear of coracohumeral ligament continuing into medial border of supraspinatus tendon
Type B	Isolated tear within crescent zone
Type C	Tear extending from lateral border of pulley system over medial border of supraspinatus tendon up to area of crescent zone

Forty-three percent of partial articular lesions observed by the authors belonged to type 1C or 2C. In addition, 64 % of patients had a concomitant disease of the long head biceps tendon; 57 % had fraying of the superior labrum; 42 % had a lesion of the superior glenohumeral ligament; and 9 % had a partial tear of the middle glenohumeral ligament.

Full-Thickness Lesions

The full-thickness lesions have an extension from the articular to the bursal side of the tendon; therefore, a direct contact between the joint and the subacromial space occurs, resulting in a mutual fluid exchange between the two anatomical spaces. Over time, a huge number of classifications were proposed. They considered both size and location of the lesion.

Snyder’s Classification

Of the proposed classifications, that of Snyder [8] obtained the greatest success and spread widely. The numerical designation is from type I to IV (Table 2). Tear degree is preceded by the letter “C” that indicates that the tear is complete; furthermore, it increases with the increase of size and complexity of the lesion; therefore, the classification also provides information on the repairability of the tendon.

Table 2

Classification of full-thickness tears according to Snyder [8]

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