Table 2.

Oxford shoulder score outcome analyses

	Mean (SD); n			Mean difference (95% CI); p value
	Decompression	Arthroscopy only	No treatment	Decompression vs arthroscopy only	Decompression vs no treatment	Arthroscopy only vs no treatment
Intention to treat
OSS at 6 months	32·7 (11·6); n=90	34·2 (9·2); n=94	29·4 (11·9); n=90	−1·3 (−3·9 to 1·3); 0·3141	2·8 (0·5 to 5·2); 0·0186	4·2 (1·8 to 6·6); 0·0014
OSS at 1 year	38·2 (10·3); n=88	38·4 (9·3); n=93	34·3 (11·8); n=84	0·3 (−2·9 to 3·5); 0·8571	3·9 (0·7 to 7·1); 0·0193	3·6 (0·6 to 6·6); 0·0193
Per protocol
OSS at 6 months	34·7 (10·9); n=70	35·5 (8·8); n=57	29·4 (11·8); n=80	−0·7 (−4·2 to 2·8); 0·6971	4·6 (1·7 to 7·5); 0·0030	5·3 (2·7 to 7·8); 0·0002
OSS at 1 year	39·4 (9·4); n=72	38·1 (9·6); n=65	33·8 (12·3); n=64	1·6 (−1·9 to 5·1); 0·3526	5·7 (2·9 to 8·4); 0·0003	3·9 (0·7 to 7·0); p=0·0175
Multiple imputation*
OSS at 6 months	32·5 (11·3); n=106	34·5 (8·8); n=103	29·6 (11·3); n=104	−1·3 (−3·9 to 1·3); 0·3237	3·1 (0·7 to 5·5); 0·0139	4·1 (1·8 to 6·4); 0·0013
OSS at 1 year	38·3 (9·7); n=106	38·4 (8·9); n=103	34·4 (10·8); n=104	0·5 (−2·6 to 3·7); 0·7338	4·1 (0·7 to 7·5); 0·0202	3·3 (0·3 to 6·4); 0·0338

The primary outcome was the Oxford Shoulder Score (OSS) at 6 months.

^*Means and SDs including imputed values, averaged over the 20 imputation runs using predictive mean matching.