Table 5. Mixed-effects model results.

A p-value less than 0.05 was considered significant.

CI, confidence interval; N/A, not available; SE, standard error;; SS, suprascapular; SSN, suprascapular notch

Anatomical variant	Number of studies	Estimate (%)	SE	95% CI (lower bound – upper bound)	P-value	Moderator estimate (decimal)		SE (Moderator)		Moderator p-value
						Moderator 1	Moderator 2	Moderator 1	Moderator 2	Moderator 1	Moderator 2
Absent SSN	26	10.578	0.0308	4.5 – 16.6	<0.001	-0.00109	0.0502	0.0417	0.0374	0.979	0.179
U-shaped SSN	25	31.7	0.0615	19.6 – 43.7	<0.001	0.242	0.130	0.0809	0.0726	0.003	0.072
V-shaped SSN	25	28.981	0.0612	17.0 – 41.0	<0.001	-0.00404	-0.1065	0.0804	0.0720	0.960	0.139
SS foramen	23	3.62	0.0135	1.0 – 6.3	0.007	0.0103	0.0168	0.0165	0.0153	0.531	0.273
SS foramen and notch	3	0.942	0.00397	0.2 – 1.7	0.018	N/A		N/A		N/A
Incomplete ossification	16	6.49	0.0105	4.4 – 8.5	<0.001	N/A		N/A		N/A
Small V-shaped	15	9.04	0.0173	5.6 – 12.4	<0.001	N/A		N/A		N/A
J-shaped	2	N/A	N/A	N/A	N/A	N/A		N/A		N/A
Double foramen	2	N/A	N/A	N/A	N/A	N/A		N/A		N/A
“Polguj method” classification
Type IA	4	12.1	0.0287	6.5 – 17.7	<0.001	N/A		N/A		N/A
Type IB	4	5.79	0.019	2.1 – 9.5	0.002	N/A		N/A		N/A
Type IC	3	7.42	0.00827	5.8 – 9.0	<0.001	N/A		N/A		N/A
Type II	4	2.1	0.00439	1.2 – 3.0	<0.001	N/A		N/A		N/A
Type IIIA	4	5.3	0.0171	1.9 – 8.7	0.002	N/A		N/A		N/A
Type IIIB	4	3.72	0.0167	0.5 – 7.0	0.026	N/A		N/A		N/A
Type IIIC	3	44.9	0.0538	34.3 – 55.4	<0.001	N/A		N/A		N/A
Type IV	4	4.35	0.00624	3.1 – 5.6	<0.001	N/A		N/A		N/A
Type V	4	15.8	0.0477	6.5 – 25.2	<0.001	N/A		N/A		N/A