Bentley 1981.

Methods	RCT, randomisation by pharmacist High quality: Delphi score 7
Participants	Chondromalacia patellae diagnosed by arthroscopy performed in patients that did not improve with 3 months treatment with isometric quadriceps exercises 30 patients, 2 bilateral, worst knee is treated 8 male, 22 female Age 15‐35 Many athletic patients
Interventions	Baseline arthroscopy for grading of cartilage damage, then randomisation (1) Aspirin (Aloxiprin) (n=16) (2) Placebo (n=13) 10 week period, during which serum levels of aspirin were monitored Repeated arthroscopy after 12 weeks
Outcomes	Subjective change in symptoms (improved, unchanged, worse) at 12 weeks Arthroscopic grading of cartilage damage at baseline and 12 weeks Arthroscopic changes (improved no change worse) at 12 weeks
Notes	4 of 16 patients did not maintain effective blood levels of between 15 and 25 mg/100 ml, due to side effects or non‐cooperation 1 drop out refused repeated arthroscopy, treatment group is not mentioned patients were not allowed aspirin during 3 month exercise period previous to aspirin treatment
Risk of bias
Bias	Authors' judgement	Support for judgement
Allocation concealment?	Low risk	A ‐ Adequate