Table 4.

Effectiveness of PRP in subacromial impingement syndrome.

Study	Study design	Patients enrolled					Outcome	Use of PRP
		Total	PRP	EG	ST	PT
Aslani et al. (61)	CR	1					60% improvement in diurnal shoulder pain. Two-fold improvement for ROM and more than 70% improvement for function	+
Nejati et al. (68)	RCT	62	31	31			L-PRP and exercise therapy were effective in reducing pain and disability, with exercise therapy proving more effective	– (L-PRP)
Say et al. (69)	RCT	60	30		30		Steroid was more effective than PRP (probably L-PRP) in terms of the Constant score and VAS at 6 weeks and 6 months	– (L-PRP)
Pasin et al. (70)	RCT	90	30		30	30	All three treatment modalities were similarly effective methods of physical therapy	0

Note. +, support the use of PRP; –, does not support the use of PRP; 0, neither support nor against PRP use.s

CR, case report; EG, exercise group; FU, follow-up; PT, physical therapy; ST, steroid.