Prosthetic design of reverse shoulder arthroplasty contributes to scapular notching and instability

Table 2 Scapular notching and instability by prosthesis design in 65 cases of reverse total shoulder arthroplasty with minimum 2-year follow-up, 2004-2011¹

Parameter	Grammont group (n = 18), n (%)	Lateral-design group (n = 47), n (%)	P-value
Scapular notching	13 (72)	11 (23)	< 0.0012
Notching severity5
Grade 1	7 (39)	8 (17)	> 0.0013
Grade 2	2 (11)	1 (2.1)	NA4
Grade 3	2 (11)	2 (4.3)	NA4
Grade 4	2 (11)	0 (0)	NA4
Instability6	3 (17)	0 (0)	0.019

¹NA: Not applicable;

²P-value from two-tailed Fisher exact test;

³Adjusted for length of follow-up using general linear model;

⁴Small values prevented determination of significant differences;

⁵Notching severity was measured according to Sirveaux classification[15];

⁶Instability was determined using clinical examination and radiographic evidence of component dislocation.