Suter 1998.

Methods	RCT, randomisation method not defined, double blind. Low quality: Delphi score 4
Participants	42 patients, identified through patient database at the University Sports Medicine Center 29 men and 13 women Age: mean 35.6, SD 8.4 Inclusion criteria: unilateral anterior knee pain syndrome of varying duration, no history of knee surgery or knee instability, quadriceps injury, or bone, meniscus or ligament injury, no history of peptic ulceration, no concurrent disease of other organ systems.
Interventions	(1) NSAID naproxen, 550 mg twice daily for 7 days (n=20) (2) placebo, twice daily for 7 days (n=22)
Outcomes	Pain reductions of averaged VAS scores before and during testing maximal contraction of knee extensors Muscle inhibition at 30 and 60 degrees of knee flexion Knee extensor moments at 30 and 60 degrees of knee flexion All outcomes were determined for the involved and the noninvolved leg
Notes	One man and two women dropped out because of drug intolerance Three men dropped out because of time constraints Analyses were performed with remaining 36 patients (no intention to treat)
Risk of bias
Bias	Authors' judgement	Support for judgement
Allocation concealment?	Unclear risk	B ‐ Unclear

ABBREVIATIONS 
 BID: twice a day (from Latin: bis in die) 
 GAGPS: glycosaminoglycan polysulphate 
 NSAID: non‐steroidal anti‐inflammatory drug 
 PFPS: patellofemoral pain syndrome 
 QID: four times a day (from Latin: quarter in die) 
 VAS: visual analogue scale