Reporting rotator cuff tears on magnetic resonance arthrography using the Snyder’s arthroscopic classification

Table 1 Snyder’s classification of rotator cuff tears

Location
A	Articular side
B	Bursal side
C	Full-thickness tears, connecting A and B sides
Severity of partial tears (A and B side)
0	Normal cuff, with smooth coverings of synovium and bursa
1	Minimal, superficial bursal or synovial irritation or slight capsular fraying in a small, localized area; usually < 1 cm
2	Actually fraying and failure of some rotator cuff fibres in addition to synovial, bursal, or capsular injury; usually < 2 cm
3	More severe rotator cuff injury, including fraying and fragmentation of tendons fibers, often involving the whole surface of a cuff tendon; usually < 3 cm
4	Very severe partial rotator cuff tear that usually contains, in addition to fraying and fragmentation of tendon tissue, a sizable flap tear and often encompasses more than a single tendon
Severity of complete tears (C)
1	Small, complete tear, such as a puncture wound
2	Moderate tear, (usually < 2 cm) that still encompasses only one of the rotator cuff tendons with no retraction of the torn ends
3	Large, complete tear involving an entire tendon with minimal retraction of the torn edge; usually 3 to 4 cm
4	Massive rotator cuff tear involving two or more rotator cuff tendons, frequently with associated retraction and scarring of the remaining tendon

Modified from Millstein and Snyder[16].

Table 2 Adaptation to magnetic resonance arthrography of arthroscopic Snyder’s classification of rotator cuff partial tears

Lesion's grade	Severity of partial tears (A or B lesion)
1	Subtle irregularities of the tendon surface with preserved thickness
2	Major irregularities of the tendon surface with preserved thickness
3	Lesions involve less than 50% of tendon diameter and lesion extension is less than 3 cm
4	Lesions involve more than 50% of tendon's diameter with an extension of more than 3 cm or the lesion involves two tendons

A: Articular side; B: Bursal side.

Table 3 Distribution of lesion severity degree on articular and bursal sides of 55 patients with a partial rotator cuff tear at the arthroscopic assessment

		Articular side tear
		A0	A1	A2	A3	A4
Bursal side tear	B0	-	1	1	2	1
	B1	3	8	0	0	0
	B2	4	5	5	3	1
	B3	0	0	1	5	2
	B4	0	0	0	1	12

A: Articular side; B: Bursal side.

Table 4 Data regarding the 5 patients with a complete tear at the reference standard assigned with a partial score at the magnetic resonance arthrography by the most experienced reader (reader 1)

Reader 1		Reference standard
Articular side	Bursal side	Complete tear
A 2	B 1	C 1
A 3	B 4	C 1
A 2	B 3	C 1
A 4	B 4	C 1
A 4	B 4	C 1

A: Articular side; B: Bursal side.

Table 5 Data on agreement of the severity degree assigned on the articular side for partial tear between magnetic resonance arthrography (according to the most experienced reader) and arthroscopy

		Reader 1
		A0	A1	A2	A3	A4
Arthroscopy	A0	7	0	0	0	0
	A1	8	6	0	0	0
	A2	2	2	3	0	0
	A3	0	0	4	7	0
	A4	0	0	0	8	8

Quadratically weighted Cohen kappa = 0.878. A: Articular side.

Table 6 Data on agreement of the severity degree assigned on the bursal side for partial lesions between magnetic resonance arthrography and arthroscopic assessment

		Reader 1
		B0	B1	B2	B3	B4
Arthroscopy	B0	5	0	0	0	0
	B1	7	4	0	0	0
	B2	4	7	7	0	0
	B3	0	0	3	5	0
	B4	0	0	0	3	10

Quadratically weighted Cohen kappa = 0.837. B: Bursal side.